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Sample records for depolarization loss analysis

  1. Depolarization ratio, SNR estimation, and polarization sensitivity analysis for a commercial Raman depolarization lidar system

    NASA Astrophysics Data System (ADS)

    Avdikos, George; Georgoussis, George

    2016-05-01

    In this paper we focus on the estimation of the Signal-to-Noise (SNR) ratio of a 3-channel commercial (Raymetics) volcanic ash detection system, (LR111-D300), already operating in UK, and also, we perform a basic lidar polarization sensitivity analysis. The results show that SNR values are higher than 10 for ranges up to 13 km for daytime conditions. This is a quite good result compared with other values presented in bibliography and prove that such system is able to detect volcanic ash detection over a range of 20 km. We also assess the lidar polarization sensitivity and then, we estimate the linear depolarization ratio. By careful choice of the optical components (emitting and receiving optics), it has been shown that uncertainties of polarization states at receiver (and thus too depolarization ratio estimation) can be much reduced.

  2. Diode-double-face-pumped Nd:YAG ceramic slab laser amplifier with low depolarization loss

    NASA Astrophysics Data System (ADS)

    Chen, Yanzhong; Fan, Zhongwei; Guo, Guangyan; Jia, Dan; He, Jianguo; Lang, Ye; Qiu, Jisi; Kang, Zhijun; Zhao, Tianzhuo; Lin, Weiran; Wang, Jiang; Xie, Tengfei; Li, Jiang; Kou, Huamin; Pan, Yubai

    2017-09-01

    A diode-double-face-pumped Nd:YAG ceramic slab laser amplifier with uniform gain distribution and low depolarization loss was presented. Energy storage of 2.6 J was achieved at 1064 nm with a repetition rate of 200 Hz and a pulse width of 200 us from a 140 mm × 40 mm × 7 mm ceramic slab at a total pump power of 1215 W, corresponding to an optical-to-optical efficiency of 42.8%. An average small signal gain of 5.45 was achieved with a standard deviation of only 0.09 in the cross section, which shown good concentration uniformity. An average depolarization loss of 2.6% at different positions of the slab was obtained due to small thermal gradient of the zigzag configuration.

  3. Thermal Stress-Induced Depolarization Loss in Conventional and Panda-Shaped Photonic Crystal Fiber Lasers

    NASA Astrophysics Data System (ADS)

    Mousavi, Seyedeh Laleh; Sabaeian, Mohammad

    2016-10-01

    We report on the modeling of the depolarization loss in the conventional and panda-shaped photonic crystal fiber lasers (PCFLs) due to the self-heating of the fiber, which we call it thermal stress-induced depolarization loss (TSIDL). We first calculated the temperature distribution over the fiber cross sections and then calculated the thermal stresses/strains as a function of heat load per meter. Thermal stress-induced birefringence (TSIB), which is defined as | n x - n y |, in the core and cladding regions was calculated. Finally, TSIDL was calculated for the conventional and panda-shaped PCFLs as a function of fiber length and, respectively, saturated values of 22 and 25 % were obtained which were independent of heat load per meter. For panda-shaped PCFLs, prior to being saturated, an oscillating and damping behavior against the fiber length was seen where in some lengths reached 35 %. The results are close to an experimental value of 30 % reported for a pulsed PCFL (Limpert et al., Opt Express 12:1313-1319, 2004) where the authors reported a degree of polarization of 70 % (i.e., a depolarization of 30 %). The most important result of this work is a saturation behavior of TSIDL at long-enough lengths of the fiber laser which is independent of heat load per meter. To our knowledge, this the first report of TSIBL for PCFLs.

  4. Losses and depolarization of ultracold neutrons on neutron guide and storage materials

    NASA Astrophysics Data System (ADS)

    Bondar, V.; Chesnevskaya, S.; Daum, M.; Franke, B.; Geltenbort, P.; Göltl, L.; Gutsmiedl, E.; Karch, J.; Kasprzak, M.; Kessler, G.; Kirch, K.; Koch, H.-C.; Kraft, A.; Lauer, T.; Lauss, B.; Pierre, E.; Pignol, G.; Reggiani, D.; Schmidt-Wellenburg, P.; Sobolev, Yu.; Zechlau, T.; Zsigmond, G.

    2017-09-01

    At Institut Laue-Langevin (ILL) and Paul Scherrer Institute (PSI), we have measured the losses and depolarization probabilities of ultracold neutrons on various materials: (i) nickel-molybdenum alloys with weight percentages of 82/18, 85/15, 88/12, 91/9, and 94/6 and natural nickel Ni100, (ii) nickel-vanadium NiV93/7, (iii) copper, and (iv) deuterated polystyrene (dPS). For the different samples, storage-time constants up to ˜460 s were obtained at room temperature. The corresponding loss parameters for ultracold neutrons, η , varied between 1.0 ×10-4 and 2.2 ×10-4 . All η values are in agreement with theory except for dPS, where anomalous losses at room temperature were established with four standard deviations. The depolarization probabilities per wall collision β measured with unprecedented sensitivity varied between 0.7 ×10-6 and 9.0 ×10-6 . Our depolarization result for copper differs from other experiments by 4.4 and 15.8 standard deviations. The β values of the paramagnetic NiMo alloys over molybdenum content show an increase of β with increasing Mo content. This is in disagreement with expectations from literature. Finally, ferromagnetic behavior of NiMo alloys at room temperature was found for molybdenum contents of 6.5 at.% or less and paramagnetic behavior for more than 8.7 at.%. This may contribute to solving an ambiguity in literature.

  5. Transitory endolymph leakage induced hearing loss and tinnitus: depolarization, biphasic shortening and loss of electromotility of outer hair cells

    NASA Technical Reports Server (NTRS)

    Zenner, H. P.; Reuter, G.; Zimmermann, U.; Gitter, A. H.; Fermin, C.; LePage, E. L.

    1994-01-01

    There are types of deafness and tinnitus in which ruptures or massive changes in the ionic permeability of the membranes lining the endolymphatic space [e.g., of the reticular lamina (RL)] are believed to allow potassium-rich endolymph to deluge the low [K+] perilymphatic fluid (e.g., in the small spaces of Nuel). This would result in a K+ intoxication of sensory and neural structures. Acute attacks of Meniere's disease have been suggested to be an important example for this event. The present study investigated the effects of transiently elevated [K+] due to the addition of artificial endolymph to the basolateral cell surface of outer hair cells (OHC) in replicating endolymph-induced K+ intoxication of the perilymph in the small spaces of Nuel. The influence of K+ intoxication of the basolateral OHC cell surface on the transduction was then examined. Intoxication resulted in an inhibition of the physiological repolarizing K+ efflux from hair cells. This induced unwanted depolarizations of the hair cells, interfering with mechanoelectrical transduction. A pathological longitudinal OHC shortening was also found, with subsequent compression of the organ of Corti possibly influencing the micromechanics of the mechanically active OHC. Both micromechanical and electrophysiological alterations are proposed to contribute to endolymph leakage induced attacks of deafness and possibly also to tinnitus. Moreover, repeated or long-lasting K+ intoxications of OHC resulted in a chronic and complete loss of OHC motility. This is suggested to be a pathophysiological basis in some patients with chronic hearing loss resulting from Meniere's syndrome.

  6. Intrinsic reduction the depolarization loss in electro-optical Q-switched laser using a rectangular KD*P crystal

    NASA Astrophysics Data System (ADS)

    Yin, Xingliang; Jiang, Menghua; Sun, Zhe; Hui, Yongling; Lei, Hong; Li, Qiang

    2017-09-01

    We presented the first demonstration of a new structure KD*P crystal as electro-optic switch, in which the thermal depolarization loss was intrinsically reduced. The thermally induced birefringence and depolarization of both cylindrical and rectangular crystalline structure were simulated. The higher pulse energy or average power output was achieved in the diode pumped E-O Q-switched laser using a rectangular KD*P crystal. At the repetition rate of 100 Hz, the maximum average output power was 27.2 W at 145 A pump current, corresponding to the pulse energy was 272 mJ with pulse width of 65 ns and the beam quality of M2=20.4. Comparing the highest average power or corresponding single pulse energy, the laser with the rectangular KD*P crystal was two times of the laser with the traditional cylindrical KD*P crystal.

  7. Design and analysis of a depolarizer for the NASA moderate resolution imaging spectrometer-tilt (MODIS-T)

    NASA Technical Reports Server (NTRS)

    Mcclain, Stephen C.; Maymon, Peter W.; Chipman, Russell A.

    1992-01-01

    The design and analysis of a depolarizer for the NASA MODIS-T spectrometer is presented. The theory of spatial pseudodepolarizer operation and its effect on linear polarization sensitivity is described. Details of the HV depolarizer design and issues of depolarizer location and material are discussed. The image doubling and aberrations induced by the depolarizer and the trade-offs between increased polarization performance and decreased image quality are also addressed. The issues considered apply directly to depolarizer design for other remote sensing instruments.

  8. Electromagnetic scattering and depolarization across rough surfaces: Full wave analysis

    NASA Astrophysics Data System (ADS)

    Bahar, Ezekiel; Huang, Guorong; Lee, Bom Son

    1995-05-01

    Full wave solutions are derived for vertically and horizontally polarized waves diffusely scattered across an interface that is two-dimensionally rough separating two different propagating media. Since the normal to the rough surface is not restricted to the reference plane of incidence, the waves are depolarized upon scattering; and the single scattered radiation fields are expressed as integrals of a surface element transmission scattering matrix that also accounts for coupling between the vertically and horizontally polarized waves. The integrations are over the rough surface area as well as the complete two-dimensional wave spectra of the radiation fields. The full wave solutions satisfy the duality and reciprocity relationships in electromagnetic theory, and the surface element scattering matrix is invariant to coordinate transformations. It is shown that in the high-frequency limit the full wave solutions reduce to the physical optics solutions, while in the low-frequency limit (for small mean square heights and slopes) the full wave solutions reduce to Rice's (1951) small perturbation solutions. Thus, the full wave solution accounts for specular point scattering as well as diffuse, Bragg-type scattering in a unified, self-consistent manner. It is therefore not necessary to use hybrid, perturbation and physical optics approaches (based on two-scale models of composite surfaces with large and small roughness scales) to determine the like- and cross-polarized fields scattered across the rough surface.

  9. Essential roles of mitochondrial depolarization in neuron loss through microglial activation and attraction toward neurons.

    PubMed

    Nam, Min-Kyung; Shin, Hyun-Ah; Han, Ji-Hye; Park, Dae-Wook; Rhim, Hyangshuk

    2013-04-10

    As life spans increased, neurodegenerative disorders that affect aging populations have also increased. Progressive neuronal loss in specific brain regions is the most common cause of neurodegenerative disease; however, key determinants mediating neuron loss are not fully understood. Using a model of mitochondrial membrane potential (ΔΨm) loss, we found only 25% cell loss in SH-SY5Y (SH) neuronal mono-cultures, but interestingly, 85% neuronal loss occurred when neurons were co-cultured with BV2 microglia. SH neurons overexpressing uncoupling protein 2 exhibited an increase in neuron-microglia interactions, which represent an early step in microglial phagocytosis of neurons. This result indicates that ΔΨm loss in SH neurons is an important contributor to recruitment of BV2 microglia. Notably, we show that ΔΨm loss in BV2 microglia plays a crucial role in microglial activation and phagocytosis of damaged SH neurons. Thus, our study demonstrates that ΔΨm loss in both neurons and microglia is a critical determinant of neuron loss. These findings also offer new insights into neuroimmunological and bioenergetical aspects of neurodegenerative disease.

  10. Spectralon spatial depolarization: towards an intrinsic characterization using a novel phase shift distribution analysis.

    PubMed

    Dupont, Jan; Orlik, Xavier; Ceolato, Romain; Dartigalongue, Thibault

    2017-05-01

    Spectralons are reference radiometric samples which exhibit a calibrated reflectance. However, in case of low reflectance samples, the degree of polarization (DOP) of scattered light is hard to characterize. Here, an accurate determination of spectralon spatial depolarization is proposed. Based on a spatially resolved polarimetric imaging system, the polarization state of the scattered light is characterized for every pixel. A statistic distribution analysis is carried out over the entire image. The relative phase shift distribution between two orthogonal components of the scattered electric field clearly exhibits a high sensitivity to the reflectance, the phase statistics following a circular Voigt profile. The intrinsic part of the spatial depolarization is demonstrated to be linked to the circular Cauchy contribution of that phase dispersion. An analytic equation is proposed to estimate the monochromatic spatially integrated DOP, as a function of the reflectance.

  11. Analysis of depolarization ratios of ClNO{sub 2} dissolved in methanol

    SciTech Connect

    Trimithioti, Marilena; Hayes, Sophia C.; Akimov, Alexey V.; Prezhdo, Oleg V.

    2014-01-07

    A detailed analysis of the resonance Raman depolarization ratio dispersion curve for the N–O symmetric stretch of nitryl chloride in methanol at excitation wavelengths spanning the D absorption band is presented. The depolarization ratios are modeled using the time-dependent formalism for Raman scattering with contributions from two excited states (2{sup 1}A{sub 1} and 3{sup 1}B{sub 1}), which are taken as linearly dissociative along the Cl–N coordinate. The analysis focuses on the interplay between different types of broadening revealing the importance of inhomogenous broadening in determining the relative contributions of the two electronic transitions. We find that the transition dipole moment (M) for 2{sup 1}A{sub 1} is greater than for 3{sup 1}B{sub 1}, in agreement with gas phase calculations in the literature [A. Lesar, M. Hdoscek, M. Muhlhauser, and S. D. Peyerimhoff, Chem. Phys. Lett. 383, 84 (2004)]. However, we find that the polarity of the solvent influences the excited state energetics, leading to a reversal in the ordering of these two states with 3{sup 1}B{sub 1} shifting to lower energies. Molecular dynamics simulations along with linear response and ab initio calculations support the evidence extracted from resonance Raman intensity analysis, providing insights on ClNO{sub 2} electronic structure, solvation effects in methanol, and the source of broadening, emphasizing the importance of a contribution from inhomogeneous linewidth.

  12. CHARACTERIZATION TESTING AND ANALYSIS OF SINGLE CELL SO2 DEPOLARIZED ELECTROLYZER

    SciTech Connect

    Steimke, J; Timothy Steeper, T

    2006-09-15

    This document reports work performed at the Savannah River National Laboratory (SRNL) that further develops the use of a proton exchange membrane or PEM-type electrochemical cell to produce hydrogen via SO{sub 2}-depolarized water electrolysis. This work was begun at SRNL in 2005. This research is valuable in achieving the ultimate goal of an economical hydrogen production process based on the Hybrid Sulfur (HyS) Cycle. The HyS Process is a hybrid thermochemical cycle that may be used in conjunction with advanced nuclear reactors or centralized solar receivers to produce hydrogen by water-splitting. Like all other sulfur-based cycles, HyS utilizes the high temperature thermal decomposition of sulfuric acid to produce oxygen. The unique aspect of HyS is the generation of hydrogen in a water electrolyzer that is operated under conditions where dissolved sulfur dioxide depolarizes the anodic reaction, resulting in substantial voltage reduction. Sulfur dioxide is oxidized at the anode, producing sulfuric acid that is sent to the acid decomposition portion of the cycle. The focus of this work was to conduct single cell electrolyzer tests in order to prove the concept of SO{sub 2}-depolarization and to determine how the results can be used to evaluate the performance of key components of the HyS Process. A test facility for conducting SO{sub 2}-depolarized electrolyzer (SDE) testing was designed, constructed and commissioned. The maximum cell current is 50 amperes, which is equivalent to a hydrogen production rate of approximately 20 liters per hour. Feed to the anode of the electrolyzer is sulfuric acid solutions containing dissolved sulfur dioxide. The partial pressure of sulfur dioxide may be varied in the range of 1 to 6 atm (15 to 90 psia). Temperatures may be controlled in the range from ambient to 80 C. Hydrogen generated at the cathode of the cell is collected for the purpose of flow measurement and composition analysis. The test facility proved to be easy to

  13. Comparison between thermal sampling and numerical analysis of thermally stimulated depolarization current peaks

    NASA Astrophysics Data System (ADS)

    Laredo, E.; Bello, A.; Hernández, M. C.; Grimau, M.

    2001-12-01

    Thermal sampling peaks recorded after windowing polarization are studied for the segmental mode in poly(ɛ-caprolactone). Also, numerical decompositions of the global thermally stimulated depolarization current peak into pure Debye contributions are performed with direct signal analysis (DSA) and simulated annealing direct signal analysis procedures for Arrhenius and Vogel-Tammann-Fulcher (VTF) temperature dependences, respectively. It is found that the results between the experimental and the numerical procedures agree very well and the approximations made in the analysis of the experimental curves are thus validated, despite the unphysical values for the relaxation parameters found by both methods when using Arrhenius relaxation times. On the contrary, when VTF relaxation times are used for the numerical decomposition, agreement is found with the results of isothermal dielectric absorption as a function of frequency, together with reasonable values for reorientation energies, pre-exponential factors and VTF temperature. Thermal sampling and DSA also compare well when studying the departure from the zero-entropy line which indicates the onset of a cooperative character in the dynamics of molecular motion. Compensation is found whenever the primary relaxation is analyzed with Arrhenius or Eyring relaxation times and does not appear when VTF relaxation times are used in the numerical decomposition.

  14. Theoretical analysis of shock induced depolarization and current generation in ferroelectrics

    NASA Astrophysics Data System (ADS)

    Agrawal, Vinamra; Bhattacharya, Kaushik

    Ferroelectric generators are used to generate large magnitude current pulse by impacting a polarized ferroelectric material. The impact causes depolarization of the material and at high impact speeds, dielectric breakdown. Depending on the loading conditions and the electromechanical boundary conditions, the current or voltage profiles obtained vary. In this study, we explore the large deformation dynamic response of a ferroelectric material. Using the Maxwell's equations, conservation laws and the second law of thermodynamics, we derive the governing equations for the phase boundary propagation as well as the driving force acting on it. We allow for the phase boundary to contain surface charges which introduces the contribution of curvature of phase boundary in the governing equations and the driving force. This type of analysis accounts for the dielectric breakdown and resulting conduction in the material. Next, we implement the equations derived to solve a one dimensional impact problem on a ferroelectric material under different electrical boundary conditions. The constitutive law is chosen to be piecewise quadratic in polarization and quadratic in the strain. We solve for the current profile generated in short circuit case and for voltage profile in open circuited case. This work was made possible by the financial support of the US Air Force Office of Scientific Research through the Center of Excellence in High Rate Deformation Physics of Heterogeneous Materials (Grant: FA 9550-12-1-0091).

  15. Analysis of shock induced depolarization and current generation in ferroelectric ceramics

    NASA Astrophysics Data System (ADS)

    Agrawal, Vinamra; Bhattacharya, Kaushik

    2015-06-01

    Ferroelectric generators are used to generate large magnitude current pulse by impacting a polarized ferroelectric material. The impact causes depolarization of the material and at high impact speeds, dielectric breakdown. The current or voltage profiles obtained vary depending on the loading conditions. In this study, we explore the large deformation dynamic response of a ferroelectric material. Using the Maxwell's equations, conservation laws and the second law of thermodynamics, we derive the governing equations for the phase boundary propagation as well as the driving force acting on it. We allow for the phase boundary to contain surface charges which introduces the contribution of curvature of phase boundary in the governing equations and the driving force. This type of analysis accounts for the dielectric breakdown and resulting conduction in the material. Next, we implement the equations derived to solve a one dimensional impact problem on a ferroelectric material under different electrical boundary conditions. The constitutive law is chosen to be piecewise quadratic in polarization and quadratic in the strain. We solve for the current profile generated in short circuit case and for voltage profile in open circuited case. This work was made possible by the financial support of the US Air Force Office of Scientific Research through the Center of Excellence in High Rate Deformation Physics of Heterogeneous Materials (Grant: FA 9550-12-1-0091).

  16. Automated detection and analysis of depolarization events in human cardiomyocytes using MaDEC.

    PubMed

    Szymanska, Agnieszka F; Heylman, Christopher; Datta, Rupsa; Gratton, Enrico; Nenadic, Zoran

    2016-08-01

    Optical imaging-based methods for assessing the membrane electrophysiology of in vitro human cardiac cells allow for non-invasive temporal assessment of the effect of drugs and other stimuli. Automated methods for detecting and analyzing the depolarization events (DEs) in image-based data allow quantitative assessment of these different treatments. In this study, we use 2-photon microscopy of fluorescent voltage-sensitive dyes (VSDs) to capture the membrane voltage of actively beating human induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs). We built a custom and freely available Matlab software, called MaDEC, to detect, quantify, and compare DEs of hiPS-CMs treated with the β-adrenergic drugs, propranolol and isoproterenol. The efficacy of our software is quantified by comparing detection results against manual DE detection by expert analysts, and comparing DE analysis results to known drug-induced electrophysiological effects. The software accurately detected DEs with true positive rates of 98-100% and false positive rates of 1-2%, at signal-to-noise ratios (SNRs) of 5 and above. The MaDEC software was also able to distinguish control DEs from drug-treated DEs both immediately as well as 10min after drug administration.

  17. Analysis of ice water by the thermally stimulated depolarized current (TSDC) method.

    PubMed

    Sato, Kazuishi; Koizumi, Toshinori; Okajima, Kunihiko

    2005-03-01

    The thermally stimulated depolarized current and temperature profiles (TSDC analysis) on iced water was proved to be an effective tool for the qualitative evaluation of various water samples, each having an independent relaxation process, brought about by a pure dipolar orientation. The method proved to be applicable to different kinds of water samples used in the experiment and tap-water samples from different suppliers. Five main peaks (A to E, in the order of increasing temperature) were observed, of which two peaks (B and D) were found for the first time. The appearance of multiple peaks suggested the existence of multi-states of the hydrogen bond, cleaved by the TSDC process. The TSDC profiles were quite reproducible when the water samples contained practically no cations. A separate addition of each cation at a low concentration level revealed that a cation with a smaller ionic radius shifted peak A to a higher temperature. For ice of tap water, which contained relatively higher amount of cations, the TSDC profiles were quite different in shape compared with the standard ice-water samples (shift of peaks A - D to higher temperature, and a strong increase in the current strength of peaks B - E). However, it was still possible to tell from which districts the water samples were supplied.

  18. Mitochondrial aquaporin-8 knockdown in human hepatoma HepG2 cells causes ROS-induced mitochondrial depolarization and loss of viability

    SciTech Connect

    Marchissio, Maria Julia; Francés, Daniel Eleazar Antonio; Carnovale, Cristina Ester; Marinelli, Raúl Alberto

    2012-10-15

    Human aquaporin-8 (AQP8) channels facilitate the diffusional transport of H{sub 2}O{sub 2} across membranes. Since AQP8 is expressed in hepatic inner mitochondrial membranes, we studied whether mitochondrial AQP8 (mtAQP8) knockdown in human hepatoma HepG2 cells impairs mitochondrial H{sub 2}O{sub 2} release, which may lead to organelle dysfunction and cell death. We confirmed AQP8 expression in HepG2 inner mitochondrial membranes and found that 72 h after cell transfection with siRNAs targeting two different regions of the human AQP8 molecule, mtAQP8 protein specifically decreased by around 60% (p < 0.05). Studies in isolated mtAQP8-knockdown mitochondria showed that H{sub 2}O{sub 2} release, assessed by Amplex Red, was reduced by about 45% (p < 0.05), an effect not observed in digitonin-permeabilized mitochondria. mtAQP8-knockdown cells showed an increase in mitochondrial ROS, assessed by dichlorodihydrofluorescein diacetate (+ 120%, p < 0.05) and loss of mitochondrial membrane potential (− 80%, p < 0.05), assessed by tetramethylrhodamine-coupled quantitative fluorescence microscopy. The mitochondria-targeted antioxidant MitoTempol prevented ROS accumulation and dissipation of mitochondrial membrane potential. Cyclosporin A, a mitochondrial permeability transition pore blocker, also abolished the mtAQP8 knockdown-induced mitochondrial depolarization. Besides, the loss of viability in mtAQP8 knockdown cells verified by MTT assay, LDH leakage, and trypan blue exclusion test could be prevented by cyclosporin A. Our data on human hepatoma HepG2 cells suggest that mtAQP8 facilitates mitochondrial H{sub 2}O{sub 2} release and that its defective expression causes ROS-induced mitochondrial depolarization via the mitochondrial permeability transition mechanism, and cell death. -- Highlights: ► Aquaporin-8 is expressed in mitochondria of human hepatoma HepG2 cells. ► Aquaporin-8 knockdown impairs mitochondrial H{sub 2}O{sub 2} release and increases ROS. ► Aquaporin

  19. Quantitative Nucleotide Level Analysis of Regulation of Translation in Response to Depolarization of Cultured Neural Cells

    PubMed Central

    Dalal, Jasbir S.; Yang, Chengran; Sapkota, Darshan; Lake, Allison M.; O'Brien, David R.; Dougherty, Joseph D.

    2017-01-01

    Studies on regulation of gene expression have contributed substantially to understanding mechanisms for the long-term activity-dependent alterations in neural connectivity that are thought to mediate learning and memory. Most of these studies, however, have focused on the regulation of mRNA transcription. Here, we utilized high-throughput sequencing coupled with ribosome footprinting to globally characterize the regulation of translation in primary mixed neuronal-glial cultures in response to sustained depolarization. We identified substantial and complex regulation of translation, with many transcripts demonstrating changes in ribosomal occupancy independent of transcriptional changes. We also examined sequence-based mechanisms that might regulate changes in translation in response to depolarization. We found that these are partially mediated by features in the mRNA sequence—notably upstream open reading frames and secondary structure in the 5′ untranslated region—both of which predict downregulation in response to depolarization. Translationally regulated transcripts are also more likely to be targets of FMRP and include genes implicated in autism in humans. Our findings support the idea that control of mRNA translation plays an important role in response to neural activity across the genome. PMID:28190998

  20. Sonoporation-induced depolarization of plasma membrane potential: analysis of heterogeneous impact.

    PubMed

    Qin, Peng; Xu, Lin; Hu, Yaxin; Zhong, Wenjing; Cai, Ping; Du, Lianfang; Jin, Lifang; Yu, Alfred C H

    2014-05-01

    Disrupting plasma membrane integrity would inevitably promote anomalous ion fluxes across the membrane and thereby upset the trans-membranous potential. In this article, we report new findings on how sonoporation as a physical membrane perforation strategy would lead to different forms of plasma membrane potential disruption. Our investigation was conducted with a customized fluorescence imaging platform that enabled live monitoring of plasma membrane potential in relation to individual sonoporation events triggered on HeLa cervical cancer cells. Sonovue microbubbles were used as sonoporation agents (added at a 4:3 cell-to-bubble ratio), and they were activated by 1-MHz pulsed ultrasound with 0.35-MPa peak negative pressure, 20-cycle pulse duration, 20-Hz pulse repetition frequency and 1-s total exposure duration. Results indicate that the plasma membrane potential response was heterogeneous among sonoporated cells: (i) membrane potential of irreversibly sonoporated cells was permanently depolarized; (ii) reversibly sonoporated cells exhibited either transient or sustained membrane depolarization; (iii) intact cells adjacent to sonoporated ones underwent transitory membrane depolarization. These findings effectively serve to substantiate the causal relationship between sonoporation and plasma membrane potential. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  1. Reexamination of depolarization in lidar measurements.

    PubMed

    Gimmestad, Gary G

    2008-07-20

    Almost all of the depolarization papers in the lidar literature employ a physically inappropriate notation and they use a definition of the depolarization ratio that is not linear in the quantity of interest. This depolarization lidar legacy is misleading and confusing. In particular, subscripts meaning parallel and perpendicular do not apply to atmospheric parameters, such as the volume backscatter coefficient, because (for linear polarization) the two components of the backscattered light are polarized in the transmitted sense and completely unpolarized; the unpolarized component is not "perpendicular." An analysis of lidar depolarization measurements with a particle scattering matrix recently provided in the literature yields algorithms for retrieving the depolarization parameter from either linear or circular depolarization lidar measurements. The analysis, notation, and definitions recommended here harmonize lidar depolarization analysis with radiative transfer theory, particle scattering theory, and standard polarization measurement techniques.

  2. Analysis of Antimicrobial-Triggered Membrane Depolarization Using Voltage Sensitive Dyes

    PubMed Central

    te Winkel, J. Derk; Gray, Declan A.; Seistrup, Kenneth H.; Hamoen, Leendert W.; Strahl, Henrik

    2016-01-01

    The bacterial cytoplasmic membrane is a major inhibitory target for antimicrobial compounds. Commonly, although not exclusively, these compounds unfold their antimicrobial activity by disrupting the essential barrier function of the cell membrane. As a consequence, membrane permeability assays are central for mode of action studies analysing membrane-targeting antimicrobial compounds. The most frequently used in vivo methods detect changes in membrane permeability by following internalization of normally membrane impermeable and relatively large fluorescent dyes. Unfortunately, these assays are not sensitive to changes in membrane ion permeability which are sufficient to inhibit and kill bacteria by membrane depolarization. In this manuscript, we provide experimental advice how membrane potential, and its changes triggered by membrane-targeting antimicrobials can be accurately assessed in vivo. Optimized protocols are provided for both qualitative and quantitative kinetic measurements of membrane potential. At last, single cell analyses using voltage-sensitive dyes in combination with fluorescence microscopy are introduced and discussed. PMID:27148531

  3. Recording, analysis, and interpretation of spreading depolarizations in neurointensive care: Review and recommendations of the COSBID research group.

    PubMed

    Dreier, Jens P; Fabricius, Martin; Ayata, Cenk; Sakowitz, Oliver W; William Shuttleworth, C; Dohmen, Christian; Graf, Rudolf; Vajkoczy, Peter; Helbok, Raimund; Suzuki, Michiyasu; Schiefecker, Alois J; Major, Sebastian; Winkler, Maren Kl; Kang, Eun-Jeung; Milakara, Denny; Oliveira-Ferreira, Ana I; Reiffurth, Clemens; Revankar, Gajanan S; Sugimoto, Kazutaka; Dengler, Nora F; Hecht, Nils; Foreman, Brandon; Feyen, Bart; Kondziella, Daniel; Friberg, Christian K; Piilgaard, Henning; Rosenthal, Eric S; Westover, M Brandon; Maslarova, Anna; Santos, Edgar; Hertle, Daniel; Sánchez-Porras, Renán; Jewell, Sharon L; Balança, Baptiste; Platz, Johannes; Hinzman, Jason M; Lückl, Janos; Schoknecht, Karl; Schöll, Michael; Drenckhahn, Christoph; Feuerstein, Delphine; Eriksen, Nina; Horst, Viktor; Bretz, Julia S; Jahnke, Paul; Scheel, Michael; Bohner, Georg; Rostrup, Egill; Pakkenberg, Bente; Heinemann, Uwe; Claassen, Jan; Carlson, Andrew P; Kowoll, Christina M; Lublinsky, Svetlana; Chassidim, Yoash; Shelef, Ilan; Friedman, Alon; Brinker, Gerrit; Reiner, Michael; Kirov, Sergei A; Andrew, R David; Farkas, Eszter; Güresir, Erdem; Vatter, Hartmut; Chung, Lee S; Brennan, K C; Lieutaud, Thomas; Marinesco, Stephane; Maas, Andrew Ir; Sahuquillo, Juan; Dahlem, Markus A; Richter, Frank; Herreras, Oscar; Boutelle, Martyn G; Okonkwo, David O; Bullock, M Ross; Witte, Otto W; Martus, Peter; van den Maagdenberg, Arn Mjm; Ferrari, Michel D; Dijkhuizen, Rick M; Shutter, Lori A; Andaluz, Norberto; Schulte, André P; MacVicar, Brian; Watanabe, Tomas; Woitzik, Johannes; Lauritzen, Martin; Strong, Anthony J; Hartings, Jed A

    2017-05-01

    Spreading depolarizations (SD) are waves of abrupt, near-complete breakdown of neuronal transmembrane ion gradients, are the largest possible pathophysiologic disruption of viable cerebral gray matter, and are a crucial mechanism of lesion development. Spreading depolarizations are increasingly recorded during multimodal neuromonitoring in neurocritical care as a causal biomarker providing a diagnostic summary measure of metabolic failure and excitotoxic injury. Focal ischemia causes spreading depolarization within minutes. Further spreading depolarizations arise for hours to days due to energy supply-demand mismatch in viable tissue. Spreading depolarizations exacerbate neuronal injury through prolonged ionic breakdown and spreading depolarization-related hypoperfusion (spreading ischemia). Local duration of the depolarization indicates local tissue energy status and risk of injury. Regional electrocorticographic monitoring affords even remote detection of injury because spreading depolarizations propagate widely from ischemic or metabolically stressed zones; characteristic patterns, including temporal clusters of spreading depolarizations and persistent depression of spontaneous cortical activity, can be recognized and quantified. Here, we describe the experimental basis for interpreting these patterns and illustrate their translation to human disease. We further provide consensus recommendations for electrocorticographic methods to record, classify, and score spreading depolarizations and associated spreading depressions. These methods offer distinct advantages over other neuromonitoring modalities and allow for future refinement through less invasive and more automated approaches.

  4. Analysis of Spike Electrogenesis and Depolarizing K Inactivation in Electroplaques of Electrophorus electricus, L

    PubMed Central

    Nakamura, Yutaka; Nakajima, Shigehiro; Grundfest, Harry

    1965-01-01

    Voltage clamp analyses, combined with pharmacological tools demonstrate the independence of reactive Na and K channels in electrically excitable membrane of eel electroplaques. Spike electrogenesis is due to Na activation and is eliminated by tetrodotoxin or mussel poison, or by substituting choline, K, Cs, or Rb for Na in the medium. The K channels remain reactive, but K activation is always absent, the electroplaques responding only with K inactivation. This is indicated by an increased resistance when the membrane is depolarized by more than about 30 mv. The resting resistance (1 to 5 ohm cm2) is dependent upon the ionic conditions, but when K inactivation occurs the resistance becomes about 10 ohm cm2 in all conditions. K inactivation does not change the EMF significantly. The transition from low to high resistance may give rise to a negative-slope voltage current characteristic, and to regenerative inactivation responses under current clamp. The further demonstration that pharmacological K inactivation (by Cs or Rb) leaves Na activation and spike electrogenesis unaffected emphasizes the independence of the reactive processes and suggests different chemical compositions for the membrane structures through which they operate. PMID:19873566

  5. Mathematical analysis of depolarization block mediated by slow inactivation of fast sodium channels in midbrain dopamine neurons

    PubMed Central

    Qian, Kun; Yu, Na; Tucker, Kristal R.; Levitan, Edwin S.

    2014-01-01

    Dopamine neurons in freely moving rats often fire behaviorally relevant high-frequency bursts, but depolarization block limits the maximum steady firing rate of dopamine neurons in vitro to ∼10 Hz. Using a reduced model that faithfully reproduces the sodium current measured in these neurons, we show that adding an additional slow component of sodium channel inactivation, recently observed in these neurons, qualitatively changes in two different ways how the model enters into depolarization block. First, the slow time course of inactivation allows multiple spikes to be elicited during a strong depolarization prior to entry into depolarization block. Second, depolarization block occurs near or below the spike threshold, which ranges from −45 to −30 mV in vitro, because the additional slow component of inactivation negates the sodium window current. In the absence of the additional slow component of inactivation, this window current produces an N-shaped steady-state current-voltage (I-V) curve that prevents depolarization block in the experimentally observed voltage range near −40 mV. The time constant of recovery from slow inactivation during the interspike interval limits the maximum steady firing rate observed prior to entry into depolarization block. These qualitative features of the entry into depolarization block can be reversed experimentally by replacing the native sodium conductance with a virtual conductance lacking the slow component of inactivation. We show that the activation of NMDA and AMPA receptors can affect bursting and depolarization block in different ways, depending upon their relative contributions to depolarization versus to the total linear/nonlinear conductance. PMID:25185810

  6. Depolarization in polarizing supermirrors

    NASA Astrophysics Data System (ADS)

    Klauser, Christine; Bigault, Thierry; Böni, Peter; Courtois, Pierre; Devishvili, Anton; Rebrova, Nataliya; Schneider, Michael; Soldner, Torsten

    2016-12-01

    We present data on depolarizing effects in polarizing mirrors. At typical magnetizing field strengths used in polarizing devices, depolarizations rise up to the percent level in the specular region and are shown to be successfully suppressed to 10-4 when increasing the magnetizing field. We show evidence linking a part of this depolarization to lateral correlation of the magnetization fluctuations in the ferromagnetic layers. Effects of the supermirror factor (m), wavelength and incidence angle are studied. The findings are applied to a crossed supermirror geometry and we report a neutron beam polarization of 99.97(1)% for a beam of wavelength λ = 5.3 Å, Δλ/λ = 0.1 (FWHM).

  7. Ischemia-induced spreading depolarization in the retina

    PubMed Central

    Srienc, Anja I; Biesecker, Kyle R; Shimoda, Angela M; Kur, Joanna

    2016-01-01

    Cortical spreading depolarization is a metabolically costly phenomenon that affects the brain in both health and disease. Following severe stroke, subarachnoid hemorrhage, or traumatic brain injury, cortical spreading depolarization exacerbates tissue damage and enlarges infarct volumes. It is not known, however, whether spreading depolarization also occurs in the retina in vivo. We report now that spreading depolarization episodes are generated in the in vivo rat retina following retinal vessel occlusion produced by photothrombosis. The properties of retinal spreading depolarization are similar to those of cortical spreading depolarization. Retinal spreading depolarization waves propagate at a velocity of 3.0 ± 0.1 mm/min and are associated with a negative shift in direct current potential, a transient cessation of neuronal spiking, arteriole constriction, and a decrease in tissue O2 tension. The frequency of retinal spreading depolarization generation in vivo is reduced by administration of the NMDA antagonist MK-801 and the 5-HT(1D) agonist sumatriptan. Branch retinal vein occlusion is a leading cause of vision loss from vascular disease. Our results suggest that retinal spreading depolarization could contribute to retinal damage in acute retinal ischemia and demonstrate that pharmacological agents can reduce retinal spreading depolarization frequency after retinal vessel occlusion. Blocking retinal spreading depolarization generation may represent a therapeutic strategy for preserving vision in branch retinal vein occlusion patients. PMID:27389181

  8. Depolarizing differential Mueller matrices.

    PubMed

    Ortega-Quijano, Noé; Arce-Diego, José Luis

    2011-07-01

    The evolution of a polarized beam can be described by the differential formulation of Mueller calculus. The nondepolarizing differential Mueller matrices are well known. However, they only account for 7 out of the 16 independent parameters that are necessary to model a general anisotropic depolarizing medium. In this work we present the nine differential Mueller matrices for general depolarizing media, highlighting the physical implications of each of them. Group theory is applied to establish the relationship between the differential matrix and the set of transformation generators in the Minkowski space, of which Lorentz generators constitute a particular subgroup.

  9. Can Turbulence Dominate Depolarization of Optical Blazars?

    NASA Astrophysics Data System (ADS)

    Guo, Xiaotong; Mao, Jirong; Wang, Jiancheng

    2017-07-01

    We carefully examine the depolarization feature of blazars in the optical and near-infrared bands using the sample of Mead et al. Magnetohydrodynamics turbulence could be one possible reason for the depolarization of optical/infrared blazars when we apply the theoretical analysis of Lazarian & Pogosyan. We further identify in the sample that the depolarization results shown in most blazars roughly obey the form of the three-dimensional anisotropic Kolmogorov scaling. The effective Faraday rotation window length scale is not small enough to resolve the polarization correlation length scale in the blazar sample. The depolarization and the related turbulent features show diversities in different blazar sources. We suggest more simultaneous observations in both the optical/infrared and the high-energy bands for the study of the blazar polarization.

  10. Simultaneous monitoring of potassium, glucose and lactate during spreading depolarization in the injured human brain – Proof of principle of a novel real-time neurochemical analysis system, continuous online microdialysis

    PubMed Central

    Rogers, Michelle L; Leong, Chi Leng; Gowers, Sally AN; Samper, Isabelle C; Jewell, Sharon L; Khan, Asma; McCarthy, Leanne; Pahl, Clemens; Tolias, Christos M; Walsh, Daniel C; Strong, Anthony J

    2016-01-01

    Spreading depolarizations occur spontaneously and frequently in injured human brain. They propagate slowly through injured tissue often cycling around a local area of damage. Tissue recovery after an spreading depolarization requires greatly augmented energy utilisation to normalise ionic gradients from a virtually complete loss of membrane potential. In the injured brain, this is difficult because local blood flow is often low and unreactive. In this study, we use a new variant of microdialysis, continuous on-line microdialysis, to observe the effects of spreading depolarizations on brain metabolism. The neurochemical changes are dynamic and take place on the timescale of the passage of an spreading depolarization past the microdialysis probe. Dialysate potassium levels provide an ionic correlate of cellular depolarization and show a clear transient increase. Dialysate glucose levels reflect a balance between local tissue glucose supply and utilisation. These show a clear transient decrease of variable magnitude and duration. Dialysate lactate levels indicate non-oxidative metabolism of glucose and show a transient increase. Preliminary data suggest that the transient changes recover more slowly after the passage of a sequence of multiple spreading depolarizations giving rise to a decrease in basal dialysate glucose and an increase in basal dialysate potassium and lactate levels. PMID:27798268

  11. Is cold paresis related to axonal depolarization?

    PubMed

    Franssen, Hessel; Gebbink, Tineke A; Wokke, John H J; van den Berg, Leonard H; van Schelven, Leonard J

    2010-09-01

    Cold paresis may occur in multifocal motor neuropathy and lower motor neuron disease. It was proposed to reflect nerve lesions where axons are depolarized due to loss of Na/K-pump activity. In those circumstances, a further decrease in pump activity by cooling may induce extra depolarization, conduction block, and weakness. Evidence for this hypothesis is incomplete because it is unknown if cold induces depolarization in human motor axons and other factors may contribute to the symptoms. To solve these questions, we examined 10 normal subjects. At 37, 25, 20, and 15°C we assessed: excitability in the median nerve, decrement on 3-Hz stimulation, pulsed Doppler of a wrist artery, and thenar muscle strength. Cooling induced: (1) findings compatible with axonal depolarization on excitability testing (fanning-in of threshold electrotonus, steepened current threshold relation, increased refractory period, decreased super- and subexcitability), (2) decreased Doppler peak systolic velocity without causing ischemia, (3) decreased muscle strength and impaired muscle relaxation. Decrement tests and compound muscle action potential amplitude remained normal. The excitability findings induced by cooling were best explained by axonal depolarization due to the effect of temperature on Na/K-pump activity. The induced weakness may be explained not only by this mechanism but also by impaired muscle contraction. © 2010 Peripheral Nerve Society.

  12. Spreading depolarization monitoring in neurocritical care of acute brain injury.

    PubMed

    Hartings, Jed A

    2017-04-01

    Spreading depolarizations are unique in being discrete pathologic entities that are well characterized experimentally and also occur commonly in patients with substantial acute brain injury. Here, we review essential concepts in depolarization monitoring, highlighting its clinical significance, interpretation, and future potential. Cortical lesion development in diverse animal models is mediated by tissue waves of mass spreading depolarization that cause the toxic loss of ion homeostasis and limit energy substrate supply through associated vasoconstriction. The signatures of such deterioration are observed in electrocorticographic recordings from perilesional cortex of patients with acute stroke or brain trauma. Experimental work suggests that depolarizations are triggered by energy supply-demand mismatch in focal hotspots of the injury penumbra, and depolarizations are usually observed clinically when other monitoring variables are within recommended ranges. These results suggest that depolarizations are a sensitive measure of relative ischemia and ongoing secondary injury, and may serve as a clinical guide for personalized, mechanistically targeted therapy. Both existing and future candidate therapies offer hope to limit depolarization recurrence. Electrocorticographic monitoring of spreading depolarizations in patients with acute brain injury provides a sensitive measure of relative energy shortage in focal, vulnerable brains regions and indicates ongoing secondary damage. Depolarization monitoring holds potential for targeted clinical trial design and implementation of precision medicine approaches to acute brain injury therapy.

  13. Fuel and oxidizer turbine loss analysis

    NASA Technical Reports Server (NTRS)

    Haas, J. E.

    1985-01-01

    The turbine losses for the fuel and oxidizer turbines at the FPL condition were assessed by a quasi-3D loss analysis method. This loss analysis method uses two flow codes - MERIDL and TSONIC - to calculate the flow velocities along the blade surfaces and endwalls. The velocities are then used as input to the boundary layer code - BLAYER - to calculate the friction losses due to incidence, secondary flow, and tip clearance. The loss analysis for the fuel turbine indicated an overall two-stage efficiency of about 90%. The largest loss was due to rotor tip clearance. The loss analysis for the oxidizer turbine is nearly completed. Results for the first stage of the two-stage design indicates an efficiency of about 80%, with high losses due to rotor incidence and blade and endwall friction.

  14. Depolarization of radiation from high-power neodymium lasers and second harmonic generation of partly depolarized radiation

    SciTech Connect

    Arifzhanov, S.B.; Gulamov, A.A.; Redkorechev, V.I.; Usmanov, T.

    1985-07-01

    A theoretical analysis is made of two mechanisms (linear and nonlinear) of depolarization of radiation emitted by high-power solid-state glass lasers: these mechanisms are anisotropy-induced in the active elements and a nonlinear rotation of the polarization ellipse. In the cases of linear and circular polarization of practical interest, a qualitative and numerical analysis is made of the influence of depolarization of the radiation on second harmonic generation by the second type of interaction in KDP crystals. It is shown that in a field of partly depolarized radiation the second harmonic generation efficiency is limited mainly by depolarization of the radiation.

  15. A comparison of Zn2+- and Ca2+- triggered depolarization of liver mitochondria reveals no evidence of Zn2+-induced permeability transition

    PubMed Central

    Devinney, Michael J.; Malaiyandi, Latha M.; Vergun, Olga; DeFranco, Donald B.; Hastings, Teresa G.; Dineley, Kirk E.

    2013-01-01

    Intracellular Zn2+ toxicity is associated with mitochondrial dysfunction. Zn2+ depolarizes mitochondria in assays using isolated organelles as well as cultured cells. Some reports suggest that Zn2+-induced depolarization results from the opening of the mitochondrial permeability transition pore (mPTP). For a more detailed analysis of this relationship, we compared Zn2+-induced depolarization with the effects of Ca2+ in single isolated rat liver mitochondria monitored with the potentiometric probe Rhodamine123. Consistent with previous work, we found that relatively low levels of Ca2+ caused rapid, complete and irreversible loss of mitochondrial membrane potential, an effect that was diminished by classic inhibitors of mPT, including high Mg2+, ADP and cyclosporine A. Zn2+ also depolarized mitochondria, but only at relatively high concentrations. Furthermore Zn2+-induced depolarization was slower, partial and sometimes reversible, and was not affected by inhibitors of mPT. We also compared the effects of Ca2+ and Zn2+ in a calcein-retention assay. Consistent with the well-documented ability of Ca2+ to induce mPT, we found that it caused rapid and substantial loss of matrix calcein. In contrast, calcein remained in Zn2+-treated mitochondria. Considered together, our results suggest that Ca2+ and Zn2+ depolarize mitochondria by considerably different mechanisms, that opening of the mPTP is not a direct consequence of Zn2+-induced depolarization, and that Zn2+ is not a particularly potent mitochondrial inhibitor. PMID:19349076

  16. Aircraft Loss-of-Control Accident Analysis

    NASA Technical Reports Server (NTRS)

    Belcastro, Christine M.; Foster, John V.

    2010-01-01

    Loss of control remains one of the largest contributors to fatal aircraft accidents worldwide. Aircraft loss-of-control accidents are complex in that they can result from numerous causal and contributing factors acting alone or (more often) in combination. Hence, there is no single intervention strategy to prevent these accidents. To gain a better understanding into aircraft loss-of-control events and possible intervention strategies, this paper presents a detailed analysis of loss-of-control accident data (predominantly from Part 121), including worst case combinations of causal and contributing factors and their sequencing. Future potential risks are also considered.

  17. Characterization of porous media by means of the depolarization metrics

    NASA Astrophysics Data System (ADS)

    Savenkov, S.; Priezzhev, A.; Oberemok, Ye.; Silfsten, P.; Ervasti, T.; Ketolainen, J.; Peiponen, K.-E.

    2012-12-01

    In this paper Mueller polarimetry is applied to study the samples with different porosity compacted from microcrystalline cellulose. We measure the whole Mueller matrices of the samples as a function of the incident angle at a wavelength of 632.8 nm. To quantify separability of the different porous samples based on differences in their Mueller matrix behavior we apply depolarization and anisotropy analysis to measured Mueller matrices by calculating parameters characterizing depolarization (depolarization index, Q(M)-metric, first and second Lorenz indices, Cloude and Lorenz entropy) and anisotropy (values and azimuths of phase and amplitude anisotropy) properties of a sample. The results show that anisotropy parameters are almost completely insensitive to the range of porosity at least at 632.8 nm. Whereas, all depolarization metrics considered are sensitive to the range of porosity. Most sensitive (not worst than 5%) among depolarization metrics are the Lorenz entropy and Q(M)-metric.

  18. Extending stochastic network calculus to loss analysis.

    PubMed

    Luo, Chao; Yu, Li; Zheng, Jun

    2013-01-01

    Loss is an important parameter of Quality of Service (QoS). Though stochastic network calculus is a very useful tool for performance evaluation of computer networks, existing studies on stochastic service guarantees mainly focused on the delay and backlog. Some efforts have been made to analyse loss by deterministic network calculus, but there are few results to extend stochastic network calculus for loss analysis. In this paper, we introduce a new parameter named loss factor into stochastic network calculus and then derive the loss bound through the existing arrival curve and service curve via this parameter. We then prove that our result is suitable for the networks with multiple input flows. Simulations show the impact of buffer size, arrival traffic, and service on the loss factor.

  19. Blade loss transient dynamic analysis of turbomachinery

    NASA Technical Reports Server (NTRS)

    Stallone, M. J.; Gallardo, V.; Storace, A. F.; Bach, L. J.; Black, G.; Gaffney, E. F.

    1982-01-01

    This paper reports on work completed to develop an analytical method for predicting the transient non-linear response of a complete aircraft engine system due to the loss of a fan blade, and to validate the analysis by comparing the results against actual blade loss test data. The solution, which is based on the component element method, accounts for rotor-to-casing rubs, high damping and rapid deceleration rates associated with the blade loss event. A comparison of test results and predicted response show good agreement except for an initial overshoot spike not observed in test. The method is effective for analysis of large systems.

  20. Blade loss transient dynamic analysis of turbomachinery

    NASA Technical Reports Server (NTRS)

    Stallone, M. J.; Gallardo, V.; Storace, A. F.; Bach, L. J.; Black, G.; Gaffney, E. F.

    1982-01-01

    This paper reports on work completed to develop an analytical method for predicting the transient non-linear response of a complete aircraft engine system due to the loss of a fan blade, and to validate the analysis by comparing the results against actual blade loss test data. The solution, which is based on the component element method, accounts for rotor-to-casing rubs, high damping and rapid deceleration rates associated with the blade loss event. A comparison of test results and predicted response show good agreement except for an initial overshoot spike not observed in test. The method is effective for analysis of large systems.

  1. Identifiability analysis of rotational diffusion tensor and electronic transition moments measured in time-resolved fluorescence depolarization experiment.

    PubMed

    Szubiakowski, Jacek P

    2014-06-14

    The subject of this paper is studies of the deterministic identifiability of molecular parameters, such as rotational diffusion tensor components and orientation of electronic transition moments, resulting from the time-resolved fluorescence anisotropy experiment. In the most general case considered, a pair of perpendicularly polarized emissions enables the unique determination of all the rotational diffusion tensor's principal components. The influence of the tensor's symmetry and the associated degeneration of its eigenvalues on the identifiability of the electronic transitions moments is systematically investigated. The analysis reveals that independently of the rotational diffusion tensor's symmetry, the transition moments involved in photoselection and emission processes cannot be uniquely identified without a priori information about their mutual orientation or their orientation with respect to the principal axes of the tensor. Moreover, it is shown that increasing the symmetry of the rotational diffusion tensor deteriorates the degree of the transition moments identifiability. To obtain these results analytically, a novel approach to solve bilinear system of equations for Markov parameters is applied. The effect of the additional information, obtained from fluorescence measurements for different molecular mobilities, to improve the identifiability at various levels of analysis is shown. The effectiveness and reliability of the target analysis method for experimental determination of the molecular parameters is also discussed.

  2. Identifiability analysis of rotational diffusion tensor and electronic transition moments measured in time-resolved fluorescence depolarization experiment

    SciTech Connect

    Szubiakowski, Jacek P.

    2014-06-14

    The subject of this paper is studies of the deterministic identifiability of molecular parameters, such as rotational diffusion tensor components and orientation of electronic transition moments, resulting from the time-resolved fluorescence anisotropy experiment. In the most general case considered, a pair of perpendicularly polarized emissions enables the unique determination of all the rotational diffusion tensor's principal components. The influence of the tensor's symmetry and the associated degeneration of its eigenvalues on the identifiability of the electronic transitions moments is systematically investigated. The analysis reveals that independently of the rotational diffusion tensor's symmetry, the transition moments involved in photoselection and emission processes cannot be uniquely identified without a priori information about their mutual orientation or their orientation with respect to the principal axes of the tensor. Moreover, it is shown that increasing the symmetry of the rotational diffusion tensor deteriorates the degree of the transition moments identifiability. To obtain these results analytically, a novel approach to solve bilinear system of equations for Markov parameters is applied. The effect of the additional information, obtained from fluorescence measurements for different molecular mobilities, to improve the identifiability at various levels of analysis is shown. The effectiveness and reliability of the target analysis method for experimental determination of the molecular parameters is also discussed.

  3. Latrunculin A depolarizes starfish oocytes.

    PubMed

    Moccia, F

    2007-12-01

    Depolymerization of the actin cytoskeleton may liberate Ca2+ from InsP3-sensitive stores in some cell types, including starfish oocytes, while inhibiting Ca2+ influx in others. However, no information is available on the modulation of membrane potential (V(m)) by actin. The present study was aimed to ascertain whether the widely employed actin depolymerizing drug, latrunculin A (Lat A), affects V(m) in mature oocytes of the starfish Astropecten aranciacus. Lat A induced a membrane depolarization which was mimicked by cytochalasin D, another popular actin disruptor, and prevented by jasplakinolide, a stabilizer of the actin network. Lat A-elicited depolarization consisted in a positive shift in V(m) which reached the threshold of activation of voltage-gated Ca2+ channels (VGCC), thus triggering an action potential. Lat A-promoted depolarization lacked the action potential in Ca2+-free sea water, while it was abolished upon removal of external Na+. Moreover, membrane depolarization was prevented by pre-injection of BAPTA and heparin, but not ryanodine. These data indicate that Lat A induces a membrane depolarization by releasing Ca2+ from InsP3Rs. The Ca2+ signal in turn activates a Ca2+-dependent Na+ entry, which causes the positive shift in V(m) and stimulates the VGCC.

  4. Confined dynamics of a ribosome-bound nascent globin: Cone angle analysis of fluorescence depolarization decays in the presence of two local motions

    PubMed Central

    Ellis, Jamie P; Culviner, Peter H; Cavagnero, Silvia

    2009-01-01

    We still know very little about how proteins achieve their native three-dimensional structure in vitro and in the cell. Folding studies as proteins emerge from the mega Dalton-sized ribosome pose special challenges due to the large size and complicated nature of the ribosome-nascent chain complex. This work introduces a combination of three-component analysis of fluorescence depolarization decays (including the presence of two local motions) and in-cone analysis of diffusive local dynamics to investigate the spatial constraints experienced by a protein emerging from the ribosomal tunnel. We focus on E. coli ribosomes and an all-α-helical nascent globin in the presence and absence of the cotranslationally active chaperones DnaK and trigger factor. The data provide insights on the dynamic nature and structural plasticity of ribosome-nascent chain complexes. We find that the sub-ns motions of the N-terminal fluorophore, reporting on the globin dynamics in the vicinity of the N terminus, are highly constrained both inside and outside the ribosomal tunnel, resulting in high-order parameters (>0.85) and small cone semiangles (<30°). The shorter globin chains buried inside the tunnel are less spatially constrained than those of a reference sequence from a natively unfolded protein, suggesting either that the two nascent chain sequences have a different secondary structure and therefore sample different regions of the tunnel or that the tunnel undergoes local structural adjustments to accommodate the globin sequence. Longer globins emerging out of the ribosomal tunnel are also found to have highly spatially constrained slow (ns) motions. There are no observable spectroscopic changes in the absence of bound chaperones. PMID:19569194

  5. Depolarization in c-cut tetragonal laser crystals

    NASA Astrophysics Data System (ADS)

    Yumashev, K. V.; Loiko, P. A.

    2016-01-01

    Thermally induced birefringence and depolarization are described analytically for diode-pumped laser discs from [0 0 1]-cut tetragonal crystals. It is shown that the depolarization losses R can be minimized by an appropriate orientation of a polarizer with respect to the crystallographic axes. Calculations are performed for tetragonal scheelite-type molybdate laser crystals, Nd:PbMoO4, Nd:CaMoO4 and Nd:NaBi(MoO4)2. Nd:CaMoO4 provides the lowest depolarization losses, R  <  15% with a very weak dependence on the absorbed pump power (for optimized light polarization, E || [1 1 0]).

  6. Scattering and Depolarization of Electromagnetic Waves--Full Wave Solutions.

    DTIC Science & Technology

    1984-01-01

    Analysis," Proceedings of the International Union of Radio Science URSI Conference at Ciudad Universitaria , Madrid, August 1983, in press. . . 13...rough land and seat3 J. The full wave approach was also used to determine the scattering and depolarization of radio waves in irregular spheroidal struc...Full Wave Solutions," Radio Science, Vol. 17, No. 5, September-October 1982, pp. 1055-1066. 4. "Scattering and Depolarization by Rough Surfaces: Full

  7. Depolarizing collisions with hydrogen: Neutral and singly ionized alkaline earths

    SciTech Connect

    Manso Sainz, Rafael; Ramos, Andrés Asensio; Bueno, Javier Trujillo; Aguado, Alfredo

    2014-06-20

    Depolarizing collisions are elastic or quasielastic collisions that equalize the populations and destroy the coherence between the magnetic sublevels of atomic levels. In astrophysical plasmas, the main depolarizing collider is neutral hydrogen. We consider depolarizing rates on the lowest levels of neutral and singly ionized alkali earths Mg I, Sr I, Ba I, Mg II, Ca II, and Ba II, due to collisions with H°. We compute ab initio potential curves of the atom-H° system and solve the quantum mechanical dynamics. From the scattering amplitudes, we calculate the depolarizing rates for Maxwellian distributions of colliders at temperatures T ≤ 10,000 K. A comparative analysis of our results and previous calculations in the literature is completed. We discuss the effect of these rates on the formation of scattering polarization patterns of resonant lines of alkali earths in the solar atmosphere, and their effect on Hanle effect diagnostics of solar magnetic fields.

  8. Dynamic Blowout Risk Analysis Using Loss Functions.

    PubMed

    Abimbola, Majeed; Khan, Faisal

    2017-08-11

    Most risk analysis approaches are static; failing to capture evolving conditions. Blowout, the most feared accident during a drilling operation, is a complex and dynamic event. The traditional risk analysis methods are useful in the early design stage of drilling operation while falling short during evolving operational decision making. A new dynamic risk analysis approach is presented to capture evolving situations through dynamic probability and consequence models. The dynamic consequence models, the focus of this study, are developed in terms of loss functions. These models are subsequently integrated with the probability to estimate operational risk, providing a real-time risk analysis. The real-time evolving situation is considered dependent on the changing bottom-hole pressure as drilling progresses. The application of the methodology and models are demonstrated with a case study of an offshore drilling operation evolving to a blowout. © 2017 Society for Risk Analysis.

  9. Correlates of spreading depolarization in human scalp electroencephalography.

    PubMed

    Drenckhahn, Christoph; Winkler, Maren K L; Major, Sebastian; Scheel, Michael; Kang, Eun-Jeung; Pinczolits, Alexandra; Grozea, Cristian; Hartings, Jed A; Woitzik, Johannes; Dreier, Jens P

    2012-03-01

    It has been known for decades that suppression of spontaneous scalp electroencephalographic activity occurs during ischaemia. Trend analysis for such suppression was found useful for intraoperative monitoring during carotid endarterectomy, or as a screening tool to detect delayed cerebral ischaemia after aneurismal subarachnoid haemorrhage. Nevertheless, pathogenesis of such suppression of activity has remained unclear. In five patients with aneurismal subarachnoid haemorrhage and four patients with decompressive hemicraniectomy after malignant hemispheric stroke due to middle cerebral artery occlusion, we here performed simultaneously full-band direct and alternating current electroencephalography at the scalp and direct and alternating current electrocorticography at the cortical surface. After subarachnoid haemorrhage, 275 slow potential changes, identifying spreading depolarizations, were recorded electrocorticographically over 694 h. Visual inspection of time-compressed scalp electroencephalography identified 193 (70.2%) slow potential changes [amplitude: -272 (-174, -375) µV (median quartiles), duration: 5.4 (4.0, 7.1) min, electrocorticography-electroencephalography delay: 1.8 (0.8, 3.5) min]. Intervals between successive spreading depolarizations were significantly shorter for depolarizations with electroencephalographically identified slow potential change [33.0 (27.0, 76.5) versus 53.0 (28.0, 130.5) min, P = 0.009]. Electroencephalography was thus more likely to display slow potential changes of clustered than isolated spreading depolarizations. In contrast to electrocorticography, no spread of electroencephalographic slow potential changes was seen, presumably due to superposition of volume-conducted electroencephalographic signals from widespread cortical generators. In two of five patients with subarachnoid haemorrhage, serial magnetic resonance imaging revealed large delayed infarcts at the recording site, while electrocorticography showed clusters

  10. Depolarizing field in ultrathin electrocalorics

    NASA Astrophysics Data System (ADS)

    Glazkova, E.; Chang, C.-M.; Lisenkov, S.; Mani, B. K.; Ponomareva, I.

    2015-08-01

    Ferroelectric thin films are considered to be among the top candidates for room-temperature electrocaloric materials as they exhibit excellent electric properties and allow application of record high electric fields. At the same time, downsizing of ferroelectric electrocalorics brings about an unwanted but unavoidable depolarizing field that could critically alter or even destroy the films' electrocaloric properties. We use an atomistic first-principles-based computational approach that does not rely on the use of Maxwell relations (i) to reveal the critical role of the depolarizing field on the electrocaloric properties of ferroelectric ultrathin films, (ii) to demonstrate the contribution of nanodomains to the electrocaloric effect in such films, and (iii) to revisit the potential limitations of the indirect approach to study electrocaloric effect in nanoscale ferroelectrics.

  11. Analysis strategies for longitudinal attachment loss data.

    PubMed

    Beck, J D; Elter, J R

    2000-02-01

    The purpose of this invited review is to describe and discuss methods currently in use to quantify the progression of attachment loss in epidemiological studies of periodontal disease, and to make recommendations for specific analytic methods based upon the particular design of the study and structure of the data. The review concentrates on the definition of incident attachment loss (ALOSS) and its component parts; measurement issues including thresholds and regression to the mean; methods of accounting for longitudinal change, including changes in means, changes in proportions of affected sites, incidence density, the effect of tooth loss and reversals, and repeated events; statistical models of longitudinal change, including the incorporation of the time element, use of linear, logistic or Poisson regression or survival analysis, and statistical tests; site vs person level of analysis, including statistical adjustment for correlated data; the strengths and limitations of ALOSS data. Examples from the Piedmont 65+ Dental Study are used to illustrate specific concepts. We conclude that incidence density is the preferred methodology to use for periodontal studies with more than one period of follow-up and that the use of studies not employing methods for dealing with complex samples, correlated data, and repeated measures does not take advantage of our current understanding of the site- and person-level variables important in periodontal disease and may generate biased results.

  12. Nonlinearity in giant depolarizing potentials

    NASA Astrophysics Data System (ADS)

    Nakatani, Hironori; Khalilov, Ilgam; Gong, Pulin; van Leeuwen, Cees

    2003-12-01

    Synchronous population discharges in immature neurons, or giant depolarizing potentials (GDPs), are considered to have an important role in the development of the functional network in hippocampus and other neural tissue before or briefly after birth. Recently, theoretical models have emphasized the possible role of chaotic, nonlinear activity at circuit level in establishing functional connectivity in neural tissue. Combining these two hypotheses leads to the prediction that GDPs have chaotic characteristics. We tested nonlinearity in GDPs recorded from transverse hippocampal slices of neonatal Wistar rats. Our results provide evidence of nonlinearity in GDP activity at circuit level.

  13. Geometry of generalized depolarizing channels

    SciTech Connect

    Burrell, Christian K.

    2009-10-15

    A generalized depolarizing channel acts on an N-dimensional quantum system to compress the 'Bloch ball' in N{sup 2}-1 directions; it has a corresponding compression vector. We investigate the geometry of these compression vectors and prove a conjecture of Dixit and Sudarshan [Phys. Rev. A 78, 032308 (2008)], namely, that when N=2{sup d} (i.e., the system consists of d qubits), and we work in the Pauli basis then the set of all compression vectors forms a simplex. We extend this result by investigating the geometry in other bases; in particular we find precisely when the set of all compression vectors forms a simplex.

  14. Depolarization Laplace transform analysis of exchangeable hyperpolarized ¹²⁹Xe for detecting ordering phases and cholesterol content of biomembrane models.

    PubMed

    Schnurr, Matthias; Witte, Christopher; Schröder, Leif

    2014-03-18

    We present a highly sensitive nuclear-magnetic resonance technique to study membrane dynamics that combines the temporary encapsulation of spin-hyperpolarized xenon ((129)Xe) atoms in cryptophane-A-monoacid (CrAma) and their indirect detection through chemical exchange saturation transfer. Radiofrequency-labeled Xe@CrAma complexes exhibit characteristic differences in chemical exchange saturation transfer-driven depolarization when interacting with binary membrane models composed of different molecular ratios of DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) and POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine). The method is also applied to mixtures of cholesterol and POPC. The existence of domains that fluctuate in cluster size in DPPC/POPC models at a high (75-98%) DPPC content induces up to a fivefold increase in spin depolarization time τ at 297 K. In POPC/cholesterol model membranes, the parameter τ depends linearly on the cholesterol content at 310 K and allows us to determine the cholesterol content with an accuracy of at least 5%. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  15. Temperature dependent impedance spectroscopy and Thermally Stimulated Depolarization Current (TSDC) analysis of disperse red 1-co-poly(methyl methacrylate) copolymers

    NASA Astrophysics Data System (ADS)

    Ko, Yee Song; Cuervo-Reyes, Eduardo; Nüesch, Frank A.; Opris, Dorina M.

    2016-04-01

    The dielectric relaxation processes of polymethyl methacrylates that have been functionalized with Disperse Red 1 (DR1) in the side chain (DR1-co-MMA) were studied with temperature dependent impedance spectroscopy and thermally stimulated depolarization current (TSDC) techniques. Copolymers with dipole contents which varied between 10 mol% and 70 mol% were prepared. All samples showed dipole relaxations above the structural-glass transition temperature (Tg). The β-relaxation of the methyl methacrylate (MMA) repeating unit was most visible in DR1(10%)-co-MMA and rapidly vanishes with higher dipole contents. DSC data reveal an increase of the Tg by 20 °C to 125°C with the inclusion of the dipole into the polymethyl methacrylate (PMMA) as side chain. The impedance data of samples with several DR1 concentrations, taken at several temperatures above Tg, have been fitted with the Havriliak-Negami (HN) function. In all cases, the fits reveal a dielectric response that corresponds to power-law dipolar relaxations. TSDC measurements show that the copolymer can be poled, and that the induced polarization can be frozen by lowering the temperature well below the glass transition. Relaxation strengths ΔƐ estimated by integrating the depolarization current are similar to those obtained from the impedance data, confirming the efficient freezing of the dipoles in the structural glass state.

  16. Characterization of natural and irradiated nails by means of the depolarization metrics

    NASA Astrophysics Data System (ADS)

    Savenkov, Sergey; Priezzhev, Alexander; Oberemok, Yevgen; Sholom, Sergey; Kolomiets, Ivan; Chunikhina, Kateryna

    2016-07-01

    Mueller polarimetry is applied to study the samples of nails: natural (or reference) and irradiated to 2 Gy ionizing radiation dose. We measure the whole Mueller matrices of the samples as a function of the scattering angle at a wavelength of 632.8 nm. We apply depolarization analysis to measured Mueller matrices by calculating the depolarization metrics [depolarization index, Q(M)-metric, first and second Lorenz indices, Cloude and Lorenz entropy] to quantify separability of the different samples of nails under study based on differences in their Mueller matrix. The results show that nail samples strongly depolarize the output light in backscattering, and irradiation in all cases results in increasing of depolarization. Most sensitive among depolarization metrics are the Lorenz entropy and Q(M)-metric.

  17. Intrinsic reduction of the depolarization in Nd:YAG crystals.

    PubMed

    Puncken, Oliver; Tünnermann, Henrik; Morehead, James J; Wessels, Peter; Frede, Maik; Neumann, Jörg; Kracht, Dietmar

    2010-09-13

    The output power of linearly polarized Nd:YAG lasers is typically limited by thermally induced birefringence, which causes depolarization. However, this effect can be reduced either by use of some kind of depolarization compensation or by use of crystals which are cut in [110]- and [100]-direction, instead of the common [111]-direction. Investigations of the intrinsic reduction of the depolarization by use of these crystals are presented. To our knowledge, this is the first probe beam-experiment describing a comparison between [100]-, [110]- and [111]-cut Nd:YAG crystals in a pump power regime between 100 and 200 W. It is demonstrated that the depolarization can be reduced by a factor of 6 in [100]-cut crystals. The simulations reveal that a reduction of depolarization by use of a [110]-cut crystal in comparison with a [100]-cut crystal only becomes possible at pump powers in the kW region. Analysis also shows that the bifocusing for [100]-cut is slightly smaller and more asymmetrical than for [111]-cut.

  18. Depolarized inactivation overcomes impaired activation to produce DRG neuron hyperexcitability in a Nav1.7 mutation in a patient with distal limb pain.

    PubMed

    Huang, Jianying; Yang, Yang; Dib-Hajj, Sulayman D; van Es, Michael; Zhao, Peng; Salomon, Jody; Drenth, Joost P H; Waxman, Stephen G

    2014-09-10

    Sodium channel Nav1.7, encoded by SCN9A, is expressed in DRG neurons and regulates their excitability. Genetic and functional studies have established a critical contribution of Nav1.7 to human pain disorders. We have now characterized a novel Nav1.7 mutation (R1279P) from a female human subject with distal limb pain, in which depolarized fast inactivation overrides impaired activation to produce hyperexcitability and spontaneous firing in DRG neurons. Whole-cell voltage-clamp recordings in human embryonic kidney (HEK) 293 cells demonstrated that R1279P significantly depolarizes steady-state fast-, slow-, and closed-state inactivation. It accelerates deactivation, decelerates inactivation, and facilitates repriming. The mutation increases ramp currents in response to slow depolarizations. Our voltage-clamp analysis showed that R1279P depolarizes channel activation, a change that was supported by our multistate structural modeling. Because this mutation confers both gain-of-function and loss-of-function attributes on the Nav1.7 channel, we tested the impact of R1279P expression on DRG neuron excitability. Current-clamp studies reveal that R1279P depolarizes resting membrane potential, decreases current threshold, and increases firing frequency of evoked action potentials within small DRG neurons. The populations of spontaneously firing and repetitively firing neurons were increased by expressing R1279P. These observations indicate that the dominant proexcitatory gating changes associated with this mutation, including depolarized steady-state fast-, slow-, and closed-state inactivation, faster repriming, and larger ramp currents, override the depolarizing shift of activation, to produce hyperexcitability and spontaneous firing of nociceptive neurons that underlie pain.

  19. Depolarization on Earth-space paths

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Sources of depolarization effects on the propagation paths of orthogonally-polarized information channels are considered. The main sources of depolarization at millimeter wave frequencies are hydrometeor absorption and scattering in the troposphere. Terms are defined. Mathematical formulations for the effects of the propagation medium characteristics and antenna performance on signals in dual polarization Earth-space links are presented. Techniques for modeling rain and ice depolarization are discussed.

  20. LOHAS: loss-of-heterozygosity analysis suite.

    PubMed

    Yang, Hsin-Chou; Chang, Lun-Ching; Huggins, Richard M; Chen, Chun-Houh; Mullighan, Charles G

    2011-05-01

    Detection of loss of heterozygosity (LOH) plays an important role in genetic, genomic and cancer research. We develop computational methods to estimate the proportion of homozygous SNP calls, identify samples with structural alterations and/or unusual genotypic patterns, cluster samples with close LOH structures and map the genomic segments bearing LOH by analyzing data of genome-wide SNP arrays or customized SNP arrays. In addition to cancer genetics/genomics, we also apply the methods to study long contiguous stretches of homozygosity (LCSH) in general populations. The LCSH analysis aids in the identification of samples with complex LCSH patterns indicative of nonrandom mating and/or meiotic recombination cold spots, separation of samples with different genetic backgrounds and sex, and mapping of regions of LCSH. Affymetrix Human Mapping 500K Set SNP data from an acute lymphoblastic leukemia study containing 304 cancer patients and 50 normal controls and from the HapMap Project containing 30 African trios, 30 Caucasian trios and 90 independent Asian samples were analyzed. We identified common gene regions of LOH, e.g., ETV6 and CDKN1B, and identified frequent regions of LCSH, e.g., the region that encompasses the centromeric gene desert region of chromosome 16. Unsupervised analysis separated cancer subtypes and ethnic subpopulations by patterns of LOH/LCSH. Simulation studies considering LOH width, effect size and heterozygous interference fraction were performed, and the results show that the proposed LOH association test has good test power and controls type 1 error well. The developed algorithms are packaged into LOHAS written in R and R GUI.

  1. Depolarization Diffusion During Weak Suprathreshold Stimulation of Cardiac Tissue

    DTIC Science & Technology

    2001-10-25

    DEPOLARIZATION DIFFUSION DURING WEAK SUPRATHRESHOLD STIMULATION OF CARDIAC TISSUE Vladimir Nikolski, Aleksandre Sambelashvili, and Igor R. Efimov...the depolarized regions. Such an activation pattern appears similar to break activation. The effect of the depolarization diffusion from depolarized...Subtitle Depolarization Diffusion During Weak Suprathreshold Stimulation of Cardiac Tissue Contract Number Grant Number Program Element Number Author(s

  2. Dynamic changes in cortical NADH fluorescence in rat focal ischemia: evaluation of the effects of hypothermia on propagation of peri-infarct depolarization by temporal and spatial analysis.

    PubMed

    Sasaki, Toshihiro; Takeda, Yoshimasa; Taninishi, Hideki; Arai, Minako; Shiraishi, Kensuke; Morita, Kiyoshi

    2009-01-02

    Suppression of peri-infarct depolarizations (PIDs) is one of the major mechanisms of hypothermic protection against transient focal cerebral ischemia. Previous studies have shown the lack of hypothermic protection against permanent focal ischemia. We hypothesized the lack of hypothermic protection was due to the poor efficacy in suppression of PIDs. To examine the hypothesis, we elucidated the effects of hypothermia on the manner of propagation of PIDs with temporal and spatial resolutions using NADH (reduced nicotinamide adenine dinucleotide) fluorescence images by illuminating the parietal-temporal cortex with ultraviolet light. Spontaneously hypertensive rats (n=14) were subjected to permanent focal ischemia by occlusion of the middle cerebral and left common carotid arteries. 2-h hypothermia (30 degrees C) was initiated before ischemia. Although hypothermia delayed the appearance of PIDs, it did not suppress their appearance. Furthermore, 54% of the PIDs enlarged the high-intensity area of NADH fluorescence in the hypothermia group, similar to the normothermia group (53%). The high-intensity area of NADH fluorescence widened by each PID was larger in the hypothermia group than in the normothermia group. These findings suggest that PIDs even in hypothermia are one of the major factors causing growth of infarction, emphasizing the importance of therapy that targets suppression of PIDs even during hypothermia.

  3. Overcoming Depolarizing Resonances with Dual Helical Partial Siberian Snakes

    SciTech Connect

    Huang, H.; Ahrens, L. A.; Bai, M.; Brown, K.; Courant, E. D.; Gardner, C.; Glenn, J. W.; Luccio, A. U.; MacKay, W. W.; Okamura, M.; Ptitsyn, V.; Roser, T.; Tepikian, S.; Tsoupas, N.; Zelenski, A.; Zeno, K.; Lin, F.; Takano, J.

    2007-10-12

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is challenging. In a medium energy accelerator, the depolarizing spin resonances are strong enough to cause significant polarization loss but full Siberian snakes cause intolerably large orbit excursions and are also not feasible since straight sections usually are too short. Recently, two helical partial Siberian snakes with double pitch design have been installed in the Brookhaven Alternating Gradient Synchrotron (AGS). With a careful setup of optics at injection and along the energy ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances otherwise encountered during acceleration to maintain a high intensity polarized beam in medium energy synchrotrons. The observation of partial snake resonances of higher than second order will also be described.

  4. Overcoming Depolarizing Resonances with Dual Helical Partial Siberian Snakes

    NASA Astrophysics Data System (ADS)

    Huang, H.; Ahrens, L. A.; Bai, M.; Brown, K.; Courant, E. D.; Gardner, C.; Glenn, J. W.; Lin, F.; Luccio, A. U.; Mackay, W. W.; Okamura, M.; Ptitsyn, V.; Roser, T.; Takano, J.; Tepikian, S.; Tsoupas, N.; Zelenski, A.; Zeno, K.

    2007-10-01

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is challenging. In a medium energy accelerator, the depolarizing spin resonances are strong enough to cause significant polarization loss but full Siberian snakes cause intolerably large orbit excursions and are also not feasible since straight sections usually are too short. Recently, two helical partial Siberian snakes with double pitch design have been installed in the Brookhaven Alternating Gradient Synchrotron (AGS). With a careful setup of optics at injection and along the energy ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances otherwise encountered during acceleration to maintain a high intensity polarized beam in medium energy synchrotrons. The observation of partial snake resonances of higher than second order will also be described.

  5. Overcoming depolarizing resonances with dual helical partial Siberian snakes.

    PubMed

    Huang, H; Ahrens, L A; Bai, M; Brown, K; Courant, E D; Gardner, C; Glenn, J W; Lin, F; Luccio, A U; Mackay, W W; Okamura, M; Ptitsyn, V; Roser, T; Takano, J; Tepikian, S; Tsoupas, N; Zelenski, A; Zeno, K

    2007-10-12

    Acceleration of polarized protons in the energy range of 5 to 25 GeV is challenging. In a medium energy accelerator, the depolarizing spin resonances are strong enough to cause significant polarization loss but full Siberian snakes cause intolerably large orbit excursions and are also not feasible since straight sections usually are too short. Recently, two helical partial Siberian snakes with double pitch design have been installed in the Brookhaven Alternating Gradient Synchrotron (AGS). With a careful setup of optics at injection and along the energy ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances otherwise encountered during acceleration to maintain a high intensity polarized beam in medium energy synchrotrons. The observation of partial snake resonances of higher than second order will also be described.

  6. Correlates of spreading depolarization in human scalp electroencephalography

    PubMed Central

    Drenckhahn, Christoph; Winkler, Maren K. L.; Major, Sebastian; Scheel, Michael; Kang, Eun-Jeung; Pinczolits, Alexandra; Grozea, Cristian; Hartings, Jed A.; Woitzik, Johannes

    2012-01-01

    It has been known for decades that suppression of spontaneous scalp electroencephalographic activity occurs during ischaemia. Trend analysis for such suppression was found useful for intraoperative monitoring during carotid endarterectomy, or as a screening tool to detect delayed cerebral ischaemia after aneurismal subarachnoid haemorrhage. Nevertheless, pathogenesis of such suppression of activity has remained unclear. In five patients with aneurismal subarachnoid haemorrhage and four patients with decompressive hemicraniectomy after malignant hemispheric stroke due to middle cerebral artery occlusion, we here performed simultaneously full-band direct and alternating current electroencephalography at the scalp and direct and alternating current electrocorticography at the cortical surface. After subarachnoid haemorrhage, 275 slow potential changes, identifying spreading depolarizations, were recorded electrocorticographically over 694 h. Visual inspection of time-compressed scalp electroencephalography identified 193 (70.2%) slow potential changes [amplitude: −272 (−174, −375) µV (median quartiles), duration: 5.4 (4.0, 7.1) min, electrocorticography–electroencephalography delay: 1.8 (0.8, 3.5) min]. Intervals between successive spreading depolarizations were significantly shorter for depolarizations with electroencephalographically identified slow potential change [33.0 (27.0, 76.5) versus 53.0 (28.0, 130.5) min, P = 0.009]. Electroencephalography was thus more likely to display slow potential changes of clustered than isolated spreading depolarizations. In contrast to electrocorticography, no spread of electroencephalographic slow potential changes was seen, presumably due to superposition of volume-conducted electroencephalographic signals from widespread cortical generators. In two of five patients with subarachnoid haemorrhage, serial magnetic resonance imaging revealed large delayed infarcts at the recording site, while electrocorticography

  7. Differential matrix formalism for depolarizing anisotropic media.

    PubMed

    Ossikovski, Razvigor

    2011-06-15

    Azzam's differential matrix formalism [J. Opt. Soc. Am. 68, 1756 (1978)], originally developed for longitudinally inhomogeneous anisotropic nondepolarizing media, is extended to include depolarizing media. The generalization is physically interpreted in terms of means and uncertainties of the elementary optical properties of the medium, as well as of three anisotropy absorption parameters introduced to describe the depolarization. The formalism results in a particularly simple mathematical procedure for the retrieval of the elementary properties of a generally depolarizing anisotropic medium, assumed to be globally homogeneous, from its experimental Mueller matrix. The approach is illustrated on literature data and the conditions of its validity are identified and discussed.

  8. Loss Analysis of IPM Motors Considering Carrier Harmonics

    NASA Astrophysics Data System (ADS)

    Yamazaki, Katsumi; Abe, Atsushi

    In this paper, we investigate losses of interior permanent magnet motors driven by PWM inverters using 3-D finite element analysis, which can estimate the eddy current loss in the permanent magnet accurately. The calculated losses are compared with the measured results and the theoretical solution to verify the validity of the analysis. The method to decompose the electromagnetic field distribution into time-harmonic components is introduced in order to investigate the effects of the harmonic fields separately and to specify the main loss factors. The variation of the magnet eddy current loss due to the division of the magnet is also investigated. It is clarified that the magnet eddy current loss of the magnet depends on the voltage modulation ratio of the inverter and the magnetic saturation of the core. It can be said that the thickness of the divided magnet should be smaller than the skin depth of the eddy currents produced by the major harmonics for the loss reduction.

  9. A mechanistic investigation of an amorphous pharmaceutical and its solid dispersions, part I: a comparative analysis by thermally stimulated depolarization current and differential scanning calorimetry.

    PubMed

    Shmeis, Rama A; Wang, Zeren; Krill, Steven L

    2004-11-01

    To explore using thermally stimulated depolarization current (TSDC), in comparison to differential scanning calorimetry (DSC), for the characterization of molecular mobility of an amorphous pharmaceutical new chemical entity (LAB687), an amorphous polymer (PVPK-30), and their combination as solid dispersions at different % drug loadings. Amorphous drug was prepared by quenching from the melt. Solid dispersions containing 10-60% of drug in polymer were prepared by solvent evaporation method. Glass transition temperatures (Tg) were determined by DSC and TSDC. In comparison to a single T. obtained from DSC for the drug substance, TSDC shows two overlapping relaxations. Both peaks correspond to a-relaxations that are associated with the glass transition, with the second peak corresponding to the rigid fraction that is difficult to be detected by DSC because it is associated with only small changes in heat capacity. Two overlapping relaxations were also observed for the polymer vs. one Tg by DSC. The lower temperature relaxation is believed to be a beta-relaxation, whereas the higher temperature transition corresponds to an alpha-relaxation. For the solid dispersions, one single peak was obtained for each of the 20% and 30% dispersions in excellent agreement with the DSC results. However, at the 40% drug load, a small shoulder was observed by TSDC at the low temperature of the main peak. This shoulder becomes more pronounced and overlaps with the main peak as the drug load increases to 50% and 60%. Agreement between the Tg values calculated by the Gordon-Taylor equation and the DSC and TSDC experimental data, especially for the 20% and 30% drug loading, indicate ideal miscibility. At higher drug loads, only by TSDC was it possible to detect the saturation level of the drug in the polymer. TSDC proved to be very sensitive in detecting small reorientational motions in solids and in separating overlapping events with only slight differences in molecular motion exhibited as

  10. Fluorescence depolarization measurements under shock compression

    NASA Astrophysics Data System (ADS)

    Wang, Jue; Banishev, Alexandr; Bassett, Will P.; Dlott, Dana D.

    2017-01-01

    Measurements of the time-dependent fluorescence depolarization of emissive probe molecules enable real-time observations of molecular rotations in shocked materials. In shocked solids, molecular rotations occur as a result of shear deformations. An apparatus is described to measure time-dependent fluorescence depolarization of shocked materials using laser-driven flyer plates and either a picosecond or a nanosecond probe laser. The emission was separated into parallel and perpendicular channels and imaged onto a streak camera. Time-dependent fluorescence depolarization of rhodamine 6G (R6G) dye dissolved in poly-methyl methacrylate (PMMA) was measured with a 16 ns duration impact at 1 km s-1. A partial depolarization of the dye emission was observed to occur during a 150 ns period after the shock.

  11. Aberrations of a horizontal-vertical depolarizer

    NASA Technical Reports Server (NTRS)

    Mcclain, Stephen C.; Chipman, Russell A.; Hillman, Lloyd W.

    1992-01-01

    Ray-trace equations for uniaxial birefringent materials are used here to derive third-order estimates for aberrations that are produced in imaging through uniaxial plates and horizontal-vertical (HV) depolarizers. An HV depolarizer is a spatial pseudodepolarizer; it converts a uniform input polarization state into a continuum of spatially varying polarization states in an output beam. An HV depolarizer consists of two birefringent wedges whose crystal axes are crossed at 90 deg. The interface between the wedges is included, which leads to a spatially varying retardance that provides the spatial pseudodepolarization. In HV depolarizers, spherical aberration, astigmatism, and image doubling are the principal aberrations for on-axis objects. Only spherical aberration occurs in isotropic plates, while the presence of birefringent wedges introduces astigmatism and image doubling. It is shown that image separation is proportional to the magnitude of the retardance variation.

  12. A Depolarizing Electrogenic Pump in Frog Muscle

    DTIC Science & Technology

    1975-08-01

    mw copy AFRRI SR75-20 AUGUST 1975 AFRRI SCIENTIFIC REPORT O ■ to A DEPOLARIZING ELECTROGENIC PUMP IN FROG MUSCLE D. Geduldig D. R...Academy of Sciences - National Research Council. AFRRI SR75-20 August 1975 A DEPOLARIZING ELECTROGENIC PUMP IN FROG MUSCLE D. GEDULDIG* D. R...INTRODUCTION When Na-enriched frog muscles are bathed in Na- and K-free saline, the small amount of potassium which could accumulate outside of the membrane

  13. Developing Ocean Subsurface Data Record from CALIPSO Depolarization Ratio Measurements

    NASA Astrophysics Data System (ADS)

    Hu, Y.; Rodier, S. D.; Zhai, P.; Josset, D. B.; Omar, A. H.

    2012-12-01

    CALIOP, the dual wavelength, polarization sensitive lidar flying aboard the CALIPSO satellite, has been operating since June 2006 and is expected to continue for several more years. CALIOP's depolarization ratio is one of the best calibrated measurements made by the A-Train sensors. Over the life of the CALIPSO mission, the stability of the CALIOP depolarization ratio calibration has remained within 1%. CALIOP's depolarization ratio measurements can be used for studying changes in the backscatter of ocean subsurface particulates. The ocean surface/subsurface depolarization ratio measurements from CALIOP together with collocated A-train instruments can be used for estimating the subsurface particulate backscatter coefficient (bbp) and the cross polarization component of the column integrated ocean subsurface backscatter signal. To derive the cross component of inte¬grated ocean subsurface backscatter signal from the depolarization ratio of CALIOP integrated ocean surface/subsurface range bins, we need theoretical estimates of the ocean surface back¬scatter cross section, which can be derived accurately from CloudSat ocean surface backscatter measurements or from AMSR-E wind speeds. Using the CALIOP cross component of the integrated ocean subsurface backscatter together with diffuse attenuation coefficient derived from MODIS, bbp can be estimated. Preliminary CALIOP data analysis shows that in the Southern Oceans, ocean subsurface backscatter has increased by about 5% since the beginning of the CALIPSO mission in June 2006. This study will: (1) introduce the CALIPSO ocean subsurface backscatter data products; (2) assess the uncertainties in the data products and comparing with in situ optics measurements, radiative transfer modeling and aircraft lidar measurements; and (3) summarize the global and regional (e.g., Gulf of Mexico region) statistics and temporal variations of the ocean subsurface backscatter from CALIPSO measurements.

  14. Analysis of beam loss induced abort kicker instability

    SciTech Connect

    Zhang W.; Sandberg, J.; Ahrens, L.; Fischer, W.; Hahn, H.; Mi, J.; Pai, C.; Tan, Y.

    2012-05-20

    Through more than a decade of operation, we have noticed the phenomena of beam loss induced kicker instability in the RHIC beam abort systems. In this study, we analyze the short term beam loss before abort kicker pre-fire events and operation conditions before capacitor failures. Beam loss has caused capacitor failures and elevated radiation level concentrated at failed end of capacitor has been observed. We are interested in beam loss induced radiation and heat dissipation in large oil filled capacitors and beam triggered thyratron conduction. We hope the analysis result would lead to better protection of the abort systems and improved stability of the RHIC operation.

  15. Loss analysis of a 1 MW class HTS synchronous motor

    NASA Astrophysics Data System (ADS)

    Baik, S. K.; Kwon, Y. K.; Kim, H. M.; Lee, J. D.; Kim, Y. C.; Park, H. J.; Kwon, W. S.; Park, G. S.

    2009-03-01

    The HTS (High-Temperature Superconducting) synchronous motor has advantages over the conventional synchronous motor such as smaller size and higher efficiency. Higher efficiency is due to smaller loss than the conventional motor, so it is important to do loss analysis in order to develop a machine with higher efficiency. This paper deals with machine losses those are dissipated in each part of a HTS synchronous motor. These losses are analyzed theoretically and compared with loss data obtained from experimental results of a 1 MW class HTS synchronous motor. Each machine loss is measured based on IEEE 115 standard and the results are analyzed and considered based on the manufacturing of the test machine.

  16. Proximity to Intrinsic Depolarizing Resonances with a Partial Siberian Snake

    NASA Astrophysics Data System (ADS)

    Crandell, D. A.; Alexeeva, L. V.; Anferov, V. A.; Blinov, B. B.; Chu, C. M.; Caussyn, D. D.; Courant, E. D.; Gladycheva, S. E.; Hu, S.; Krisch, A. D.; Nurushev, T. S.; Phelps, R. A.; Ratner, L. G.; Varzar, S. M.; Wong, V. K.; Derbenev, Ya. S.; Lee, S. Y.; Rinckel, T.; Schwandt, P.; Sperisen, F.; Stephenson, E. J.; von Przewoski, B.; Baiod, R.; Russell, A. D.; Ohmori, C.; Sato, H.

    1996-05-01

    Partial Siberian snakes are effective in overcoming imperfection depolarizing resonances, but they may also change the crossing energy for intrinsic depolarizing resonances. We experimentally investigated the effect of a partial Siberian snake near intrinsic depolarizing resonances with stored 140 MeV and 160 MeV polarized proton beams. Using various partial Siberian snake strengths up to 30%, depolarization was observed; this may be due to a change in the spin precession frequency which moves the energy of nearby intrinsic depolarizing resonances.

  17. Zinc depolarized electrochemical CO2 concentration

    NASA Technical Reports Server (NTRS)

    Woods, R. R.; Marshall, R. D.; Schubert, F. H.

    1975-01-01

    Two zinc depolarized electrochemical carbon dioxide concentrator concepts were analytically and experimentally evaluated for portable life support system carbon dioxide (CO2) removal application. The first concept, referred to as the zinc hydrogen generator electrochemical depolarized CO2 concentrator, uses a ZHG to generate hydrogen for direct use in an EDC. The second concept, referred to as the zinc/electrochemical depolarized concentrator, uses a standard EDC cell construction modified for use with the Zn anode. The Zn anode is consumed and subsequently regenerated, thereby eliminating the need to supply H2 to the EDC for the CO2 removal process. The evaluation was based primarily on an analytical evaluation of the two ZnDCs at projected end item performance and hardware design levels. Both ZnDC concepts for PLSS CO2 removal application were found to be noncompetitive in both total equivalent launch weight and individual extravehicular activity mission volume when compared to other candidate regenerable PLSS CO2 scrubbers.

  18. Spin depolarization in semiconductor spin detectors

    NASA Astrophysics Data System (ADS)

    Chen, W. M.; Buyanova, I. A.; Oka, Y.; Abernathy, C. R.; Pearton, S. J.

    2006-02-01

    A brief review is given of our recent experimental results from in-depth investigations of spin depolarization and underlying physical mechanisms within semiconductor spin detectors based on II-VIs (e.g. Zn(Cd)Se quantum wells) and III-Vs (e.g. InGaN quantum wells), which are relevant to applications for spin-LEDs based on ZnMnSe/Zn(Cd)Se and GaMnN/InGaN structures. By employing cw and time-resolved magneto-optical and optical spin orientation spectroscopy in combination with tunable laser excitation, we show that spin depolarization within these spin detectors is very efficient and is an important factor limiting efficiency of spin detection. Detailed physical mechanisms leading to efficient spin depolarization will be discussed.

  19. UV light phototransduction depolarizes human melanocytes.

    PubMed

    Bellono, Nicholas W; Oancea, Elena

    2013-01-01

    Exposure of human skin to low doses of solar UV radiation (UVR) causes increased pigmentation, while chronic exposure is a powerful risk factor for skin cancers. The mechanisms mediating UVR detection in skin, however, remain poorly understood. Our recent studies revealed that UVR activates a retinal-dependent G protein-coupled signaling pathway in melanocytes. This phototransduction pathway leads to the activation of transient receptor potential A1 (TRPA1) ion channels, elevation of intracellular calcium (Ca( 2+)) and rapid increase in cellular melanin content. Here we report that physiological doses of solar-like UVR elicit a retinal-dependent membrane depolarization in human epidermal melanocytes. This transient depolarization correlates with delayed inactivation time of the UVR-evoked photocurrent and with sustained Ca( 2+) responses required for early melanin synthesis. Thus, the cellular depolarization induced by UVR phototransduction in melanocytes is likely to be a critical signaling mechanism necessary for the protective response represented by increased melanin content.

  20. Capturing Depolarization Information in GPS Reflections

    NASA Technical Reports Server (NTRS)

    Kelly, Kenneth C.

    2000-01-01

    The state of the surface of the ocean has a prominent effect on the depolarization of the circularly polarized emissions of the GPS satellites. The system designers election to capture the important information carries with it the need to implement the data extraction in a cost efficient manner. Antenna components, and associated networks for deriving depolarization information are described. For typical sea states the polarization characteristics of the reflected GPS signal vary rapidly with time so various methods for recording the changes are discussed.

  1. Analysis of winding losses in high frequency foil wound inductors

    SciTech Connect

    Kutkut, N.H.; Novotny, D.W.; Divan, D.M.; Yeow, E.

    1995-12-31

    The design of high power and high frequency foil wound inductors is not a straightforward task. At high frequencies, additional losses occur within the foil windings due to the eddy currents induced by skin, proximity, fringing and other ac effects. In addition, the winding structure greatly affects the distribution of losses within the windings. In this paper, the various loss mechanisms of a foil winding are analyzed and quantified. Both analytical and finite element analysis tools are utilized to investigate and understand the different loss mechanisms. The results show a strong correlation between the current and field distributions within the windings where the current is always attracted to the high field regions. By shaping and controlling the field distribution in a given design, the current distribution can be improved which results in an improvement in the winding losses.

  2. Loss Exposure and Risk Analysis Methodology (LERAM) Project Database Design.

    DTIC Science & Technology

    1996-06-01

    MISREPS) to more capably support system safety engineering concepts such as hazard analysis and risk management. As part of the Loss Exposure and Risk ... Analysis Methodology (LERAM) project, the research into the methods which we employ to report, track, and analyze hazards has resulted in a series of low

  3. Atomic and Molecular Depolarizing Collision Rates

    NASA Astrophysics Data System (ADS)

    Bommier, V.

    2009-06-01

    This paper is divided in three parts: after having recalled the different types of collisions with the different types of perturbers and having provided rough orders of magnitude of the collision rates, three cases are discussed. Although the most frequent type of depolarizing collision is the one of the collisions with the surrounding Hydrogen atoms, we discuss in the first part a particular case where the depolarizing collision effect is due to collisions with electrons and protons. This is the case of the Hydrogen lines observed in solar prominences. We recall how the interpretation of polarization observations in two lines has led to the joint determination of the magnetic field vector and the electron and proton density, and we show that this density determination gives results in agreement with the densities determined by interpretation of the Stark effect, provided that this last effect be evaluated in the impact approximation scheme which is indeed more valid than the quasistatic approach at these densities. In the second part, we describe a method that has been recently developed for the computation of the depolarizing rates in the case of collisions with the neutral Hydrogen atom. The case of molecular lines is less favourable, because, even if depolarizing collision rates computation may be soon expected and begin to be done inside the ground level of the molecule, calculations inside the excited states are far from the present ability. In the third part, we present an example where the excited state depolarizing rates were evaluated together with the magnetic field through the differential Hanle effect interpretation, based on the fact that the molecule provides a series of lines of different sensitivities that can be compared. This led to an experimental/observational determination of these rates, waiting for future theoretical computations for comparison.

  4. Depolarization field effect on dielectric and piezoelectric properties of particulate ferroelectric ceramic-polymer composites

    NASA Astrophysics Data System (ADS)

    Ma, Fengde D.; Wang, Yu U.

    2015-03-01

    The effects of depolarization field on the dielectric and piezoelectric properties of ferroelectric ceramic particle-filled polymer-matrix composites are investigated at the underlying domain level. Phase field modeling and simulation reveals that the macroscopic properties of the composites are dominated by depolarization field effect, which depends on the arrangement and alignment rather than the size or internal grain structure of the ferroelectric particulates. It is found that 0-3 particulate composites with random dispersion of ferroelectric particles behave essentially like linear dielectric rather than ferroelectric materials, and domain-level analysis reveals the physical mechanism for lack of domain switching or hysteresis as attributed to strong depolarization effect. Thus, without effective reduction or elimination of the depolarization field, the composites cannot benefit from the functional fillers regardless of their superior properties. In order to exhibit the desired ferroelectric behaviors, it necessitates continuous ferroelectric phase connectivity in the composites.

  5. Reliability analysis based on the losses from failures.

    PubMed

    Todinov, M T

    2006-04-01

    The conventional reliability analysis is based on the premise that increasing the reliability of a system will decrease the losses from failures. On the basis of counterexamples, it is demonstrated that this is valid only if all failures are associated with the same losses. In case of failures associated with different losses, a system with larger reliability is not necessarily characterized by smaller losses from failures. Consequently, a theoretical framework and models are proposed for a reliability analysis, linking reliability and the losses from failures. Equations related to the distributions of the potential losses from failure have been derived. It is argued that the classical risk equation only estimates the average value of the potential losses from failure and does not provide insight into the variability associated with the potential losses. Equations have also been derived for determining the potential and the expected losses from failures for nonrepairable and repairable systems with components arranged in series, with arbitrary life distributions. The equations are also valid for systems/components with multiple mutually exclusive failure modes. The expected losses given failure is a linear combination of the expected losses from failure associated with the separate failure modes scaled by the conditional probabilities with which the failure modes initiate failure. On this basis, an efficient method for simplifying complex reliability block diagrams has been developed. Branches of components arranged in series whose failures are mutually exclusive can be reduced to single components with equivalent hazard rate, downtime, and expected costs associated with intervention and repair. A model for estimating the expected losses from early-life failures has also been developed. For a specified time interval, the expected losses from early-life failures are a sum of the products of the expected number of failures in the specified time intervals covering the

  6. Analysis of Apex Seal Friction Power Loss in Rotary Engines

    NASA Technical Reports Server (NTRS)

    Handschuh, Robert F.; Owen, A. Karl

    2010-01-01

    An analysis of the frictional losses from the apex seals in a rotary engine was developed. The modeling was initiated with a kinematic analysis of the rotary engine. Next a modern internal combustion engine analysis code was altered for use in a rotary engine to allow the calculation of the internal combustion pressure as a function of rotor rotation. Finally the forces from the spring, inertial, and combustion pressure on the seal were combined to provide the frictional horsepower assessment.

  7. Aircraft Accident Prevention: Loss-of-Control Analysis

    NASA Technical Reports Server (NTRS)

    Kwatny, Harry G.; Dongmo, Jean-Etienne T.; Chang, Bor-Chin; Bajpai, Guarav; Yasar, Murat; Belcastro, Christine M.

    2009-01-01

    The majority of fatal aircraft accidents are associated with loss-of-control . Yet the notion of loss-of-control is not well-defined in terms suitable for rigorous control systems analysis. Loss-of-control is generally associated with flight outside of the normal flight envelope, with nonlinear influences, and with an inability of the pilot to control the aircraft. The two primary sources of nonlinearity are the intrinsic nonlinear dynamics of the aircraft and the state and control constraints within which the aircraft must operate. In this paper we examine how these nonlinearities affect the ability to control the aircraft and how they may contribute to loss-of-control. Examples are provided using NASA s Generic Transport Model.

  8. Depolarization canals and interstellar turbulence

    NASA Astrophysics Data System (ADS)

    Fletcher, A.; Shukurov, A.

    Recent radio polarization observations have revealed a plethora of unexpected features in the polarized Galactic radio background that arise from propagation effects in the random (turbulent) interstellar medium. The canals are especially striking among them, a random network of very dark, narrow regions clearly visible in many directions against a bright polarized Galactic synchrotron background. There are no obvious physical structures in the ISM that may have caused the canals, and so they have been called Faraday ghosts. They evidently carry information about interstellar turbulence but only now is it becoming clear how this information can be extracted. Two theories for the origin of the canals have been proposed; both attribute the canals to Faraday rotation, but one invokes strong gradients in Faraday rotation in the sky plane (specifically, in a foreground Faraday screen) and the other only relies on line-of-sight effects (differential Faraday rotation). In this review we discuss the physical nature of the canals and how they can be used to explore statistical properties of interstellar turbulence. This opens studies of magnetized interstellar turbulence to new methods of analysis, such as contour statistics and related techniques of computational geometry and topology. In particular, we can hope to measure such elusive quantities as the Taylor microscale and the effective magnetic Reynolds number of interstellar MHD turbulence.

  9. Analysis of serum zinc and copper concentrations in hair loss.

    PubMed

    Kil, Min Seong; Kim, Chul Woo; Kim, Sang Seok

    2013-11-01

    It is well known that some trace elements such as zinc and copper play a significant role in many forms of hair loss. However, the effect of zinc and copper in the pathogenesis of hair loss is still unknown. The purpose of this study is to evaluate the zinc and copper status in each of four types of hair loss. A study was carried out with 30 health controls and 312 patients who were diagnosed with alopecia areata (AA), male pattern hair loss, female pattern hair loss and telogen effluvium (TE) (2008 to 2011; Hallym University Kangdong Sacred Heart Hospital). Zinc and copper serum concentrations were evaluated between controls and each of four types of hair loss patients. In all of the hair loss patients, the mean serum zinc was 84.33±22.88, significantly lower than the control group (97.94±21.05 µg/dl) (p=0.002), whereas the serum copper was 96.44±22.62, which was not significantly different (p=0.975). The analysis of each group showed that all groups of hair loss had statistically lower zinc concentration, but not copper concentrations. However, the ratio of the patients with serum zinc concentration lower than 70 µg/dl was significantly high in only the AA group (odds ratio, OR 4.02; confidence interval, CI 1.13 to 14.31) and the TE group (OR 1.12; CI 1.12 to 17.68). The data led to the hypothesis of zinc metabolism disturbances playing a key role in hair loss, especially AA and TE, whereas the effect of copper on hair growth and shedding cycles still needs more study.

  10. A scattering model for rain depolarization

    NASA Technical Reports Server (NTRS)

    Wiley, P. H.; Stutzman, W. L.; Bostian, C. W.

    1973-01-01

    A method is presented for calculating the amount of depolarization caused by precipitation for a propagation path. In the model the effects of each scatterer and their interactions are accounted for by using a series of simplifying steps. It is necessary only to know the forward scattering properties of a single scatterer. For the case of rain the results of this model for attenuation, differential phase shift, and cross polarization agree very well with the results of the only other model available, that of differential attenuation and differential phase shift. Calculations presented here show that horizontal polarization is more sensitive to depolarization than is vertical polarization for small rain drop canting angle changes. This effect increases with increasing path length.

  11. Electron beam depolarization in a damping ring

    SciTech Connect

    Minty, M.

    1993-04-01

    Depolarization of a polarized electron beam injected into a damping ring is analyzed by extending calculations conventionally applied to proton synchrotrons. Synchrotron radiation in an electron ring gives rise to both polarizing and depolarizing effects. In a damping ring, the beam is stored for a time much less than the time for self polarization. Spin flip radiation may therefore be neglected. Synchrotron radiation without spin flips, however, must be considered as the resonance strength depends on the vertical betatron oscillation amplitude which changes as the electron beam is radiation damped. An expression for the beam polarization at extraction is derived which takes into account radiation damping. The results are applied to the electron ring at the Stanford Linear Collider and are compared with numerical matrix formalisms.

  12. Improved calibration method for depolarization lidar measurement.

    PubMed

    Liu, Bo; Wang, Zhien

    2013-06-17

    An improved calibration method for lidar depolarization measurement is described. With this method the system constants including the electronic gain ratio of the parallel and perpendicular channels, the optical reflectance and transmission parameters of the polarizing beam splitter, and the linear polarization ratio of the emitting laser beam can be determined conveniently by using lidar measurements with a half-wave plate oriented at selected angles.

  13. Hyperpolarization/depolarization on human spermatozoa.

    PubMed

    Calzada, L; Salazar, E L; Macias, H

    1991-01-01

    The accumulation of the lipophilic cation radiolabeled triphenylmethylphosphonium (TPMP+) was utilized to determine the resting membrane potential across the plasma membrane (psi) of human sperm. Washed sperm were suspended and incubated in low-K+ and high-K+ medium and allowed to take up the cation to a steady state (20 min at 37 degrees C). By using this differential, the value obtained was inserted in the Nernst equation and the value yielded a psi of -69 +/- 2 mV. When the Na+ or K+ concentration is high in the medium, the accumulation of TPMP+ in the membrane sperm cells was increased or decreased, respectively, inducing hyperpolarization and depolarization of the membrane 20% and 85%, respectively. The presence of divalent cations Zn++ and Mg++ in the incubation medium both induced a hyperpolarization of 10% and 8.6%, respectively. The addition of specific reagents such as p-chloromercuribenzenosulfonate and ethylenediaminetetraacetic acid sodium salt both decreased the psi 35% and 58%, respectively. The agents acting on the sperm cell membrane, such as dithiothreitol and progesterone, both induced hyperpolarization and depolarization of the membrane 16% and 40%, respectively. The presence of propranolol and L-alpha-lysophosphatidylcholine, which affect the ionic gradients present across the plasma membrane, both induced a depolarization from 43% and 92%, respectively. Finally the psi was glucose-dependent. The result of these studies was that, by the use of agents causing hyperpolarization or depolarization, we obtained changes in the psi of -83.4 +/- 2.2 mV, until -6 +/- 0.6 mV changes of -76.8 +/- 2 mV translated across the sperm cell membrane.

  14. An Analysis of Losses to the Southern Commercial Timberland Base

    Treesearch

    Ian A. Munn; David Cleaves

    1998-01-01

    Demographic and physical factors influencing the conversion of commercial timberland iu the south to non-forestry uses between the last two Forest Inventory Analysis (FIA) surveys were investigated. GIS techniques linked Census data and FIA plot level data. Multinomial logit regression identified factors associated with losses to the timberland base. Conversion to...

  15. Uptake and Loss of Carbon Dioxide in Volumetric Analysis.

    ERIC Educational Resources Information Center

    Macca, Carlo

    1986-01-01

    Discusses the use of ratio diagrams, which plot the calculations of equilibrium concentrations of the species of the carbonate system. Provides examples to describe how these diagrams can be used to illustrate the behavior systems of interest in volumetric analysis, where absorption or loss of carbon dioxide takes place. (TW)

  16. Unemployment and Underemployment: A Narrative Analysis about Loss

    ERIC Educational Resources Information Center

    Blustein, David L.; Kozan, Saliha; Connors-Kellgren, Alice

    2013-01-01

    In this study, we conducted a narrative analysis of interviews with unemployed and underemployed adults to better understand their experiences and to learn how they are coping with job loss. Seven men and six women from diverse backgrounds who were receiving career exploration and job search services were interviewed at a one-stop career center in…

  17. Unemployment and Underemployment: A Narrative Analysis about Loss

    ERIC Educational Resources Information Center

    Blustein, David L.; Kozan, Saliha; Connors-Kellgren, Alice

    2013-01-01

    In this study, we conducted a narrative analysis of interviews with unemployed and underemployed adults to better understand their experiences and to learn how they are coping with job loss. Seven men and six women from diverse backgrounds who were receiving career exploration and job search services were interviewed at a one-stop career center in…

  18. Compton effect thermally activated depolarization dosimeter

    DOEpatents

    Moran, Paul R.

    1978-01-01

    A dosimetry technique for high-energy gamma radiation or X-radiation employs the Compton effect in conjunction with radiation-induced thermally activated depolarization phenomena. A dielectric material is disposed between two electrodes which are electrically short circuited to produce a dosimeter which is then exposed to the gamma or X radiation. The gamma or X-radiation impinging on the dosimeter interacts with the dielectric material directly or with the metal composing the electrode to produce Compton electrons which are emitted preferentially in the direction in which the radiation was traveling. A portion of these electrons becomes trapped in the dielectric material, consequently inducing a stable electrical polarization in the dielectric material. Subsequent heating of the exposed dosimeter to the point of onset of ionic conductivity with the electrodes still shorted through an ammeter causes the dielectric material to depolarize, and the depolarization signal so emitted can be measured and is proportional to the dose of radiation received by the dosimeter.

  19. Regional Soiling Stations for PV: Soling Loss Analysis

    SciTech Connect

    TamizhMani, G.; King, B.; Venkatesan, A.; Deline, Chris; Pavgi, A.; Tatapudi, S.; Kuitche, J.; Chokor, A.; El Asmar, M.

    2016-11-21

    The soiling loss factor (SLF) of photovoltaic (PV) modules/system is an interplay between the dust frequency and intensity of the site, rain frequency and intensity of the site, tilt angle and height of the module installation, and wind speed and humidity of the site. The integrated area of the downward peaks of the SLF time series plots for a year provides the annual soiling loss for the system at each tilt angle. Sandia National Laboratories, in collaboration with Arizona State University, installed five regional soiling stations around the country and collected soiling loss data over a year. Four of these soiling stations are located at the U.S. Department of Energy Regional Test Centers (Florida, Albuquerque, Colorado and Vermont), while the fifth station is located at the Arizona State University Photovoltaic Reliability Lab (Arizona). This paper presents an analysis on the SLF for each test site at ten different tilt angles. Based on the analysis of a yearlong data obtained in 2015, it appears to indicate that the Arizona site experienced the highest annual soiling loss with a significant dependence on the tilt angle while the other four sites experienced a negligibly small annual soiling loss with practically no dependence on the tilt angle.

  20. Analysis of hydrodynamic losses for various types of aortic valves

    NASA Astrophysics Data System (ADS)

    Starobin, I. M.; Lupachev, S. P.; Dolgopolov, R. V.; Zaiko, V. M.; Kas'yanov, V. A.; Mungalov, D. D.; Morov, G. V.

    1985-05-01

    The creation of an automated computer-controlled hydraulic stand made it possible to measure the main hydrodynamic parameters of the flow through the investigated HVP and to determine the coefficients of Eq. (2) of fluid flow in the test chamber of the stand. The coefficients found can serve as a criterion of a comparative assessment of the hydrodynamics of HVPs. An analysis of the coefficients showed that the main contribution to pressure losses across ball and disc valves is made by viscous and convective effects. An analysis of inertial losses confirmed the presence of oscillations of the ball closing elements of the AKCh-3-06 valve around the props of the stroke limiters and made it possible to assess them quantitatively. For leaflet valves the contribution of inertial losses to the total pressure losses is more considerable than in the case of disc and ball valves both in the regime of an increase of power of the output and in the regime of a constant power. The mechanical properties of the material of leaflet valves have an effect on the hydrodynamic characteristics. The advantage of the investigated leaflet valves consists not only in that they have smaller total hydraulic losses compared with the other valves, but also in that they provide a high amplitude of pulsations of the blood stream in the case of insufficient contractility of the heart.

  1. Greater weight loss among men participating in a commercial weight loss program: a pooled analysis of 2 randomized controlled trials.

    PubMed

    Barraj, Leila M; Murphy, Mary M; Heshka, Stanley; Katz, David L

    2014-02-01

    Being overweight and obese are significant health concerns for men and women, yet despite comparable needs for effective weight loss and maintenance strategies, little is known about the success of commercial weight loss programs in men. This study tests the hypothesis that men participating in a commercial weight loss program (Weight Watchers) had significantly greater weight loss than men receiving limited support from health professionals for weight loss (controls). A pooled analysis of weight loss and related physiologic parameter data from 2 randomized clinical trials was conducted. After 12 months, analysis of covariance tests showed that men in the commercial program group (n = 85) lost significantly more weight (P < .01) than men in the control group (n = 84); similar significant differences were observed for body mass index and waist circumference. These results suggest that participation in a commercial weight loss program may be a more effective means to lose weight and maintain weight loss.

  2. AC Loss Analysis on the Superconducting Coupling Magnet in MICE

    SciTech Connect

    Wu, Hong; Wang, Li; Green, Michael; Li, LanKai; Xu, FengYu; Liu, XiaoKun; Jia, LinXinag

    2008-07-08

    A pair of coupling solenoids is used in MICE experiment to generate magnetic field which keeps the muons within the iris of thin RF cavity windows. The coupling solenoids have a 1.5-meter inner diameter and will produce 7.4 T peak magnetic field. Three types of AC losses in coupling solenoid are discussed. The affect of AC losses on the temperature distribution within the cold mass during charging and rapid discharging process is analyzed also. The analysis result will be further confirmed by the experiment of the prototype solenoid for coupling solenoid, which will be designed, fabricated and tested at ICST.

  3. Weight loss motivations: a latent class analysis approach.

    PubMed

    Lemon, Stephenie C; Schneider, Kristin L; Wang, Monica L; Liu, Qin; Magner, Robert; Estabrook, Barbara; Druker, Susan; Pbert, Lori

    2014-07-01

    To identify subgroups of adults with respect to weight loss motivations and assess factors associated with subgroup membership. A cross-sectional survey among 414 overweight/ obese employees in 12 Massachusetts high schools was conducted. Latent class analysis (LCA) defined distinct weight loss motivation classes. Multinomial logistic regression assessed participant characteristics with class membership. Three classes emerged: improving health; improving health and looking/feeling better; and improving health, looking/feeling, better and improving personal/social life. Compared to class 1, class 2 was more likely to be female and younger and class 3 was more likely to be female, younger, have children at home, and perceive themselves as very over-weight. Findings can inform targeted weight loss interventions.

  4. Uncertainty analysis for computer model projections of hurricane losses.

    PubMed

    Iman, Ronald L; Johnson, Mark E; Watson, Charles C

    2005-10-01

    Projecting losses associated with hurricanes is a complex and difficult undertaking that is wrought with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 to 3 billion dollars in losses late on August 12 to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm hit the resort areas of Charlotte Harbor near Punta Gorda and then went on to Orlando in the central part of the state, with early poststorm estimates converging on a damage estimate in the 28 to 31 billion dollars range. Comparable damage to central Florida had not been seen since Hurricane Donna in 1960. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has recognized the role of computer models in projecting losses from hurricanes. The FCHLPM established a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a Holland B parameter hurricane wind field model. Uncertainty analysis quantifies the expected percentage reduction in the uncertainty of wind speed and loss that is attributable to each of the input variables.

  5. Analysis of loss of time value during road maintenance project

    NASA Astrophysics Data System (ADS)

    Sudarsana, Dewa Ketut; Sanjaya, Putu Ari

    2017-06-01

    Lane closure is frequently performed in the execution of the road maintenance project. It has a negative impact on road users such as the loss of vehicle operating costs and the loss of time value. Nevertheless, analysis on loss of time value in Indonesia has not been carried out. The parameter of time value for the road users was the minimum wage city/region approach. Vehicle speed of pre-construction was obtained by observation, while the speed during the road maintenance project was predicted by the speed of the pre-construction by multiplying it with the speed adjustment factor. In the case of execution of the National road maintenance project in the two-lane two-way urban and interurban road types in the fiscal year of 2015 in Bali province, the loss of time value was at the average of IDR 12,789,000/day/link road. The relationship of traffic volume and loss of time value of the road users was obtained by a logarithm model.

  6. Multiple Tune Jumps to Overcome Horizontal Depolarizing Resonances

    NASA Astrophysics Data System (ADS)

    Huang, H.; Ahrens, L. A.; Bai, M.; Brown, K. A.; Dutheil, Y.; Gardner, C.; Glenn, J. W.; Lin, F.; Mackay, W. W.; Meot, F.; Poblaguev, A.; Ranjbar, V.; Roser, T.; Schoefer, V.; Tepikian, S.; Tsoupas, N.; Yip, K.; Zelenski, A.; Zeno, K.

    2016-02-01

    Imperfection and vertical intrinsic depolarizing resonances have been overcome by the two partial Siberian snakes in the Alternative Gradient Synchrotron(AGS). The relatively weak but numerous horizontal resonances are the main source of polarization loss in the AGS. A pair of horizontal tune jump quads have been used to overcome these weak resonances. The locations of the two quads have to be chosen such that the disturbance to the beam optics is minimum. The emittance growth has to be mitigated for this method to work. In addition, this technique needs very accurate jump timing. Using two partial Siberian snakes, with vertical tune inside the spin tune gap and 80% polarization at AGS injection, polarized proton beam had reached 1.5 × 1011 proton per bunch with 65% polarization. With the tune jump timing optimized and emittance preserved, more than 70% polarization with 2 × 1011 protons per bunch has been achieved.

  7. Depolarization of polarized light caused by high altitude clouds. 1: Depolarization of lidar induced by cirrus.

    PubMed

    Sun, Y Y; Li, Z P; Bösenberg, J

    1989-09-01

    A scattering model is described for the investigation of depolarization of polarized light caused by ice clouds. The scattering by a single particle is described by refraction, reflection, and diffraction. The ice cloud is assumed to be a random mixture of hexagonal columns and plates of random orientation and size. Multiple scattering effects are included by means of a Monte Carlo method, where single photon histories are constructed from random samples of the distributions governing the basic scattering parameters. The dependence of depolarization on cloud extinction coefficient, receiver field of view, and mixing ratio of columns to plates are studied. Lidar measurements of depolarization by a high altitude cirrus cloud are presented and discussed within the frame of the present model. Good agreement can be obtained assuming a variation of crystal shape distribution with height.

  8. Energy loss analysis of an integrated space power distribution system

    NASA Technical Reports Server (NTRS)

    Kankam, M. D.; Ribeiro, P. F.

    1992-01-01

    The results of studies related to conceptual topologies of an integrated utility-like space power system are described. The system topologies are comparatively analyzed by considering their transmission energy losses as functions of mainly distribution voltage level and load composition. The analysis is expedited by use of a Distribution System Analysis and Simulation (DSAS) software. This recently developed computer program by the Electric Power Research Institute (EPRI) uses improved load models to solve the power flow within the system. However, present shortcomings of the software with regard to space applications, and incompletely defined characteristics of a space power system make the results applicable to only the fundamental trends of energy losses of the topologies studied. Accountability, such as included, for the effects of the various parameters on the system performance can constitute part of a planning tool for a space power distribution system.

  9. Energy loss analysis of an integrated space power distribution system

    NASA Technical Reports Server (NTRS)

    Kankam, M. D.; Ribeiro, P. F.

    1992-01-01

    The results of studies related to conceptual topologies of an integrated utility-like space power system are described. The system topologies are comparatively analyzed by considering their transmission energy losses as functions of mainly distribution voltage level and load composition. The analysis is expedited by use of a Distribution System Analysis and Simulation (DSAS) software. This recently developed computer program by the Electric Power Research Institute (EPRI) uses improved load models to solve the power flow within the system. However, present shortcomings of the software with regard to space applications, and incompletely defined characteristics of a space power system make the results applicable to only the fundamental trends of energy losses of the topologies studied. Accountability, such as included, for the effects of the various parameters on the system performance can constitute part of a planning tool for a space power distribution system.

  10. Spontaneous mechanical activity in depolarized frog ventricle

    PubMed Central

    1976-01-01

    Spontaneous mechanical activity can be produced in depolarized frog ventricle by bathing the tissue in a solution with low Na, Iow Ca, and high K+. The contractions can be inhibited by depleting the tissue of Ca first, but they are relatively insensitive to changes in either extracellular [Ca++] or [Ca++]/[Na+]2. They are terminated very rapidly by raising [Na+] to 40 mM. Local anesthetics enhance the spontaneous activity in proportion to the concentration of their free base form. These contractions occur relatively rhythmically for several hours. Since the preparation is multicellular, this suggests a mechanism for intercellular communication without change in membrane potential. PMID:822122

  11. A Clinical Analysis of Sudden Sensorineural Hearing Loss Cases

    PubMed Central

    Lee, Hyun Soo; Lee, You Jae; Kang, Bo Sung; Lee, Ji Sung

    2014-01-01

    Background and Objectives High-dose systemic steroid therapy is the mainstay treatment for sudden sensorineural hearing loss (SSNHL). Recovery rates from SSNHL range are about 47-63% and are influenced by various prognostic factors. To evaluate the prognostic value of specific clinical parameters, we reviewed 289 cases by clinical and statistical analysis. Subjects and Methods This study included 289 patients with SSNHL who visited the Department of Otolaryngology at Soonchunhyang University Hospital from January 2005 to December 2012. The cases were reviewed retrospectively based on clinical charts. Hearing improvement was evaluated in relation to pure-tone audiogram results, duration between SSNHL onset and time of initial treatment, seasonal incidence, dizziness, patient age, degree of hearing loss, patterns of initial pure-tone audiogram and presence of underlying disease. Results Hearing improvement was observed in 196 of 289 (67.8%) patients; such improvement began within 7 days in most patients, followed by rapid hearing recovery. Cases that failed to show improvement within 14 days were unlikely to achieve hearing recovery. The more severe the hearing loss during the early stage, the lower the hearing recovery rates. Patients aged less than 60 years appear to have better prognosis of hearing improvement compared to those who are over 60 years. Conclusions Important prognostic factors for recovery in patients with SSNHL include the time of initiating treatment after symptom onset, the degree of early-stage hearing loss, and the age of the affected patient. PMID:25279228

  12. Strengthening the weak link: Built Environment modelling for loss analysis

    NASA Astrophysics Data System (ADS)

    Millinship, I.

    2012-04-01

    Methods to analyse insured losses from a range of natural perils, including pricing by primary insurers and catastrophe modelling by reinsurers, typically lack sufficient exposure information. Understanding the hazard intensity in terms of spatial severity and frequency is only the first step towards quantifying the risk of a catastrophic event. For any given event we need to know: Are any structures affected? What type of buildings are they? How much damaged occurred? How much will the repairs cost? To achieve this, detailed exposure information is required to assess the likely damage and to effectively calculate the resultant loss. Modelling exposures in the Built Environment therefore plays as important a role in understanding re/insurance risk as characterising the physical hazard. Across both primary insurance books and aggregated reinsurance portfolios, the location of a property (a risk) and its monetary value is typically known. Exactly what that risk is in terms of detailed property descriptors including structure type and rebuild cost - and therefore its vulnerability to loss - is often omitted. This data deficiency is a primary source of variations between modelled losses and the actual claims value. Built Environment models are therefore required at a high resolution to describe building attributes that relate vulnerability to property damage. However, national-scale household-level datasets are often not computationally practical in catastrophe models and data must be aggregated. In order to provide more accurate risk analysis, we have developed and applied a methodology for Built Environment modelling for incorporation into a range of re/insurance applications, including operational models for different international regions and different perils and covering residential, commercial and industry exposures. Illustrated examples are presented, including exposure modelling suitable for aggregated reinsurance analysis for the UK and bespoke high resolution

  13. Multifaceted roles for astrocytes in spreading depolarization

    PubMed Central

    Seidel, Jessica L.; Escartin, Carole; Ayata, Cenk; Bonvento, Gilles; Shuttleworth, C. William

    2015-01-01

    Spreading depolarizations (SD) are coordinated waves of synchronous depolarization, involving large numbers of neurons and astrocytes as they spread slowly through brain tissue. The recent identification of SDs as likely contributors to pathophysiology in human subjects has led to a significant increase in interest in SD mechanisms, and possible approaches to limit the numbers of SDs or their deleterious consequences in injured brain. Astrocytes regulate many events associated with SD. SD initiation and propagation is dependent on extracellular accumulation of K+ and glutamate, both of which involve astrocytic clearance. SDs are extremely metabolically demanding events, and signaling through astrocyte networks is likely central to the dramatic increase in regional blood flow that accompanies SD in otherwise healthy tissues. Astrocytes may provide metabolic support to neurons following SD, and may provide a source of adenosine that inhibits neuronal activity following SD. It is also possible that astrocytes contribute to the pathophysiology of SD, as a consequence of excessive glutamate release, facilitation of NMDA receptor activation, brain edema due to astrocyte swelling, or disrupted coupling to appropriate vascular responses after SD. Direct or indirect evidence has accumulated implicating astrocytes in many of these responses, but much remains unknown about their specific contributions, especially in the context of injury. Conversion of astrocytes to a reactive phenotype is a prominent feature of injured brain, and recent work suggests that the different functional properties of reactive astrocytes could be targeted to limit SDs in pathophysiological conditions. PMID:26301517

  14. Fractal texture analysis of the healing process after bone loss.

    PubMed

    Borowska, Marta; Szarmach, Janusz; Oczeretko, Edward

    2015-12-01

    Radiological assessment of treatment effectiveness of guided bone regeneration (GBR) method in postresectal and postcystal bone loss cases, observed for one year. Group of 25 patients (17 females and 8 males) who underwent root resection with cystectomy were evaluated. The following combination therapy of intraosseous deficits was used, consisting of bone augmentation with xenogenic material together with covering regenerative membranes and tight wound closure. The bone regeneration process was estimated, comparing the images taken on the day of the surgery and 12 months later, by means of Kodak RVG 6100 digital radiography set. The interpretation of the radiovisiographic image depends on the evaluation ability of the eye looking at it, which leaves a large margin of uncertainty. So, several texture analysis techniques were developed and used sequentially on the radiographic image. For each method, the results were the mean from the 25 images. These methods compute the fractal dimension (D), each one having its own theoretic basis. We used five techniques for calculating fractal dimension: power spectral density method, triangular prism surface area method, blanket method, intensity difference scaling method and variogram analysis. Our study showed a decrease of fractal dimension during the healing process after bone loss. We also found evidence that various methods of calculating fractal dimension give different results. During the healing process after bone loss, the surfaces of radiographic images became smooth. The result obtained show that our findings may be of great importance for diagnostic purpose. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Sensitivity analysis for computer model projections of hurricane losses.

    PubMed

    Iman, Ronald L; Johnson, Mark E; Watson, Charles C

    2005-10-01

    Projecting losses associated with hurricanes is a complex and difficult undertaking that is fraught with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 billion dollars to 3 billion dollars in losses late on the 12th to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm struck the resort areas of Charlotte Harbor and moved across the densely populated central part of the state, with early poststorm estimates in the 28 dollars to 31 billion dollars range, and final estimates converging at 15 billion dollars as the actual intensity at landfall became apparent. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has a great appreciation for the role of computer models in projecting losses from hurricanes. The FCHLPM contracts with a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a sophisticated computer model based on the Holland wind field. Sensitivity analyses presented in this article utilize standardized regression coefficients to quantify the contribution of the computer input variables to the magnitude of the wind speed.

  16. Elastic depolarization of OH(A) by He and Ar: a comparative study.

    PubMed

    Costen, M L; Livingstone, R; McKendrick, K G; Paterson, G; Brouard, M; Chadwick, H; Chang, Y-P; Eyles, C J; Aoiz, F J; Kłos, J

    2009-12-31

    Two color polarization spectroscopy has been employed to measure the collisional depolarization of OH(A(2)Sigma(+), v = 1) by He and Ar. Complementary experiments using Zeeman quantum beat spectroscopy have also been performed to determine separately the cross sections for rotational energy transfer (RET) out of selected rotational levels of OH(A, v = 0) + Ar, as well as those for elastic depolarization. This has been achieved by dispersing the emission, so as to observe a single fluorescence transition. Elastic depolarization of OH(A) by Ar is found to be significant with that for loss of rotational alignment exceeding that for loss of orientation. In the case of OH(A) + He, the polarization spectroscopy measurements suggest that elastic depolarization plays a relatively minor role in the loss of the polarization signal compared with RET. The experimental data for OH(A) + Ar are compared in detail with the results of quasi-classical trajectory calculations that accommodate the effects of electron spin. These classical calculations are assessed against the results obtained using full close-coupled open shell quantum mechanical scattering methods. Overall the level of agreement between the two experiments, and between experiment and theory, is very reasonable. Surprisingly, at low N the elastic depolarization cross sections for OH(A) + Ar are found to be quite similar in magnitude to those observed for OH(X) + Ar despite the fact that the well depth in the latter system is considerably smaller than that for OH(A)-Ar. However, for OH(A) + Ar the depolarization cross sections are insensitive to N in the range 1-14. It is proposed that this behavior partly reflects the relatively anisotropic nature of the potential energy surface, which exhibits deep wells of different depths at the two linear configurations OH(A)-Ar and Ar-OH(A), and partly the nature of elastic depolarizing collisions, which must occur with a velocity component perpendicular to the plane of rotation

  17. Spatial Durbin model analysis macroeconomic loss due to natural disasters

    NASA Astrophysics Data System (ADS)

    Kusrini, D. E.; Mukhtasor

    2015-03-01

    Magnitude of the damage and losses caused by natural disasters is huge for Indonesia, therefore this study aimed to analyze the effects of natural disasters for macroeconomic losses that occurred in 115 cities/districts across Java during 2012. Based on the results of previous studies it is suspected that it contains effects of spatial dependencies in this case, so that the completion of this case is performed using a regression approach to the area, namely Analysis of Spatial Durbin Model (SDM). The obtained significant predictor variable is population, and predictor variable with a significant weighting is the number of occurrences of disasters, i.e., disasters in the region which have an impact on other neighboring regions. Moran's I index value using the weighted Queen Contiguity also showed significant results, meaning that the incidence of disasters in the region will decrease the value of GDP in other.

  18. Weight-loss dieting behavior: an economic analysis.

    PubMed

    Rosin, Odelia

    2012-07-01

    In light of the widespread phenomena of diet failure and excessive dieting, this paper presents a theoretical economic analysis of the decision-making process of weight-loss dieting. The paper incorporates behavioral elements involved in the process of dieting: effort exerted in dieting, influence of social norms concerning body weight, time-inconsistent present biased preferences, and a distinction between naiveté and sophistication. The model explains cyclic dieting and provides interesting insights on the extent of weight-loss dieting. The extent of dieting is an increasing function of initial body weight and a decreasing function of the effort exerted in dieting and the strength of social norms concerning ideal weight. Income and diet strictness have an ambiguous effect. In addition, greater dieting efforts are not necessarily balanced against a slowdown in body metabolism or a higher initial body weight.

  19. Theoretical analysis of sound transmission loss through graphene sheets

    SciTech Connect

    Natsuki, Toshiaki; Ni, Qing-Qing

    2014-11-17

    We examine the potential of using graphene sheets (GSs) as sound insulating materials that can be used for nano-devices because of their small size, super electronic, and mechanical properties. In this study, a theoretical analysis is proposed to predict the sound transmission loss through multi-layered GSs, which are formed by stacks of GS and bound together by van der Waals (vdW) forces between individual layers. The result shows that the resonant frequencies of the sound transmission loss occur in the multi-layered GSs and the values are very high. Based on the present analytical solution, we predict the acoustic insulation property for various layers of sheets under both normal incident wave and acoustic field of random incidence source. The scheme could be useful in vibration absorption application of nano devices and materials.

  20. Rate-loss analysis of an efficient quantum repeater architecture

    NASA Astrophysics Data System (ADS)

    Guha, Saikat; Krovi, Hari; Fuchs, Christopher A.; Dutton, Zachary; Slater, Joshua A.; Simon, Christoph; Tittel, Wolfgang

    2015-08-01

    We analyze an entanglement-based quantum key distribution (QKD) architecture that uses a linear chain of quantum repeaters employing photon-pair sources, spectral-multiplexing, linear-optic Bell-state measurements, multimode quantum memories, and classical-only error correction. Assuming perfect sources, we find an exact expression for the secret-key rate, and an analytical description of how errors propagate through the repeater chain, as a function of various loss-and-noise parameters of the devices. We show via an explicit analytical calculation, which separately addresses the effects of the principle nonidealities, that this scheme achieves a secret-key rate that surpasses the Takeoka-Guha-Wilde bound—a recently found fundamental limit to the rate-vs-loss scaling achievable by any QKD protocol over a direct optical link—thereby providing one of the first rigorous proofs of the efficacy of a repeater protocol. We explicitly calculate the end-to-end shared noisy quantum state generated by the repeater chain, which could be useful for analyzing the performance of other non-QKD quantum protocols that require establishing long-distance entanglement. We evaluate that shared state's fidelity and the achievable entanglement-distillation rate, as a function of the number of repeater nodes, total range, and various loss-and-noise parameters of the system. We extend our theoretical analysis to encompass sources with nonzero two-pair-emission probability, using an efficient exact numerical evaluation of the quantum state propagation and measurements. We expect our results to spur formal rate-loss analysis of other repeater protocols and also to provide useful abstractions to seed analyses of quantum networks of complex topologies.

  1. Losses as Modulators of Attention: Review and Analysis of the Unique Effects of Losses over Gains

    ERIC Educational Resources Information Center

    Yechiam, Eldad; Hochman, Guy

    2013-01-01

    It has been shown that in certain situations losses exert a stronger effect on behavior than respective gains, and this has been commonly explained by the argument that losses are given more weight in people's decisions than respective gains. However, although much is understood about the effect of losses on cognitive processes and behavior, 2…

  2. Losses as Modulators of Attention: Review and Analysis of the Unique Effects of Losses over Gains

    ERIC Educational Resources Information Center

    Yechiam, Eldad; Hochman, Guy

    2013-01-01

    It has been shown that in certain situations losses exert a stronger effect on behavior than respective gains, and this has been commonly explained by the argument that losses are given more weight in people's decisions than respective gains. However, although much is understood about the effect of losses on cognitive processes and behavior, 2…

  3. Depolarization of laser beam propagating through atmosphere based on multiple Rayleigh scattering model

    NASA Astrophysics Data System (ADS)

    Zhang, Dai; Hao, Shiqi; Wang, Lei; Zhao, Qi

    2016-10-01

    An analytical formula model which is used to describe laser beam's depolarization characteristics is solved based on multiple Rayleigh scattering model. Firstly, by using Stokes vector to characterize intensity and polarization, while at the same time using Mueller matrix and rotation matrix to characterize polarization changing in scattering procedure, a single scattering model is built. Then, a multiple scattering model is built considering the effects of atmospheric absorbing and scattering attenuation. The received light's Stokes vectors through multiple scattering procedure are separately solved. At last, on the basis of multiple scattering vectors, the depolarization characteristics of laser beam propagation through atmosphere are estimated though calculating ratio of depolarization and polarized angle shifting. The numerical analysis based on analytical conclusion of this paper shows that for a horizontal polarized laser beam, its ratio of depolarization is about 1% and polarized angle shifting is about 0.3° when propagates through atmosphere and arrives into the receiver on the ground, and both the above characteristics have only a small change compared with the change of cloud's depth. The findings of these research show that Rayleigh scattering from atmosphere has a weak effect on the laser beam's polarization status. The multiple scattering model and Stokes vector analytical formulas raised in the paper could also be used to study the depolarization characteristics of ellipse polarized laser beam and partially polarized laser beam propagating through atmosphere. The research findings of this paper will have theoretical guiding significances in the domain of laser communication, laser detection and laser imaging.

  4. AGS tune jump system to cross horizontal depolarization resonances overview

    SciTech Connect

    Glenn, J.W.; Ahrens, L.; Fu, W.; Mi, J.L.; Rosas, P.; Schoefer, V.; Theisen, C.; Altinbas, Z.

    2011-03-28

    Two partial snakes overcome the vertical depolarizing resonances in the AGS. But a new type of depolarizing intrinsic resonance from horizontal motion appeared. We reduce these using horizontal tune jumps timed to these resonances. We gain a factor of six in crossing rate with a tune jump of 0.05 in 100 {micro}s. Two quadrapoles, we described in 2009, pulse 42 times, the current matching beam energy. The power supplies for these quads are described in detail elsewhere in this conference. The controls for the Jump Quad system is based on a BNL designed Quad Function Generator. Two modules are used; one for timing, and one to supply reference voltages. Synchronization is provided by a proprietary serial bus, the Event Link. The AgsTuneJump application predicts the times of the resonances during the AGS cycle and calculates the power supply trigger times from externally collected tune and energy versus time data and the Low and High PS voltage functions from a voltage to current model of the power supply. The system was commissioned during runs 09 & 10 and is operational. Many beam effects are described elsewhere. The TuneJump system has worked well and has caused little trouble save for the perturbations in the lattice having such a large effect due to our need to run with the vertical tune within a few thousandths of the integer tune. As these problems were mostly sorted out by correcting the 6th harmonic orbit distortions which caused a large 18 theta beta wave. Also running with minimal chromaticity reduces emittance growth. There are still small beta waves which are being addressed. The timing of the pulses is still being investigated, but as each crossing causes minimal polarization loss, this is a lengthy process.

  5. Gravitational depolarization of ultracold neutrons: Comparison with data

    NASA Astrophysics Data System (ADS)

    Afach, S.; Ayres, N. J.; Baker, C. A.; Ban, G.; Bison, G.; Bodek, K.; Fertl, M.; Franke, B.; Geltenbort, P.; Green, K.; Griffith, W. C.; van der Grinten, M.; Grujić, Z. D.; Harris, P. G.; Heil, W.; Hélaine, V.; Iaydjiev, P.; Ivanov, S. N.; Kasprzak, M.; Kermaidic, Y.; Kirch, K.; Koch, H.-C.; Komposch, S.; Kozela, A.; Krempel, J.; Lauss, B.; Lefort, T.; Lemière, Y.; Musgrave, M.; Naviliat-Cuncic, O.; Pendlebury, J. M.; Piegsa, F. M.; Pignol, G.; Plonka-Spehr, C.; Prashanth, P. N.; Quéméner, G.; Rawlik, M.; Rebreyend, D.; Ries, D.; Roccia, S.; Rozpedzik, D.; Schmidt-Wellenburg, P.; Severijns, N.; Shiers, D.; Thorne, J. A.; Weis, A.; Wursten, E.; Zejma, J.; Zenner, J.; Zsigmond, G.

    2015-09-01

    We compare the expected effects of so-called gravitationally enhanced depolarization of ultracold neutrons to measurements carried out in a spin-precession chamber exposed to a variety of vertical magnetic-field gradients. In particular, we have investigated the dependence upon these field gradients of spin-depolarization rates and also of shifts in the measured neutron Larmor precession frequency. We find excellent qualitative agreement, with gravitationally enhanced depolarization accounting for several previously unexplained features in the data.

  6. Analysis of Predisposing Factors for Hearing Loss in Adults.

    PubMed

    Lee, Joong Seob; Choi, Hyo Geun; Jang, Jeong Hun; Sim, Songyong; Hong, Sung Kwang; Lee, Hyo-Jeong; Park, Bumjung; Kim, Hyung-Jong

    2015-08-01

    We aimed to estimate the effects of various risk factors on hearing level in Korean adults, using data from the Korea National Health and Nutrition Examination Survey. We examined data from 13,369 participants collected between 2009 and 2011. Average hearing thresholds at low (0.5, 1, and 2 kHz) and high frequencies (3, 4, and 6 kHz), were investigated in accordance with various known risk factors via multiple regression analysis featuring complex sampling. We additionally evaluated data from 4,810 participants who completed a questionnaire concerned with different types of noise exposure. Low body mass index, absence of hyperlipidemia, history of diabetes mellitus, low incomes, low educational status, and smoking were associated with elevated low frequency hearing thresholds. In addition, male sex, low body mass index, absence of hyperlipidemia, low income, low educational status, smoking, and heavy alcohol consumption were associated with elevated high frequency hearing thresholds. Participants with a history of earphone use in noisy circumstances demonstrated hearing thresholds which were 1.024 dB (95% CI: 0.176 to 1.871; P = 0.018) higher, at low-frequencies, compared to participants without a history of earphone use. Our study suggests that low BMI, absence of hyperlipidemia, low household income, and low educational status are related with hearing loss in Korean adults. Male sex, smoking, and heavy alcohol use are related with high frequency hearing loss. A history of earphone use in noisy circumstances is also related with hearing loss.

  7. Optical and electronic loss analysis of mesoporous solar cells

    NASA Astrophysics Data System (ADS)

    Kovalsky, Anton; Burda, Clemens

    2016-07-01

    We review the art of complete optical and electronic characterization of the popular mesoporous solar cell motif. An overview is given of how the mesoporous paradigm is applied to solar cell technology, followed by a discussion on the variety of techniques available for thoroughly probing efficiency leaching mechanisms at every stage of the energy transfer pathway. Some attention is dedicated to the rising importance of computational results to augment loss analysis due to the complexity of solar cell devices, which have emergent properties that are important to account for, but difficult to measure, such as parasitic absorption.

  8. Valley depolarization in monolayer WSe2

    PubMed Central

    Yan, Tengfei; Qiao, Xiaofen; Tan, Pingheng; Zhang, Xinhui

    2015-01-01

    We have systematically examined the circular polarization of monolayer WSe2 at different temperature, excitation energy and exciton density. The valley depolarization in WSe2 is experimentally confirmed to be governed by the intervalley electron-hole exchange interaction. More importantly, a non-monotonic dependence of valley circular polarization on the excitation power density has been observed, providing the experimental evidence for the non-monotonic dependence of exciton intervalley scattering rate on the excited exciton density. The physical origination of our experimental observations has been proposed to be in analogy to the D′yakonov-Perel′ mechanism that is operative in conventional GaAs quantum well systems. Our experimental results are fundamentally important for well understanding the valley pseudospin relaxation in atomically thin transition metal dichalcogenides. PMID:26490157

  9. On Subregional Analysis of Cartilage Loss from Knee MRI.

    PubMed

    Jørgensen, Dan R; Lillholm, Martin; Genant, Harry K; Dam, Erik B

    2013-04-01

    Understanding how knee cartilage is affected by osteoarthritis (OA) is critical in the development of sensitive biomarkers that may be used as surrogate endpoints in clinical trials. The objective of this study was to analyze longitudinal changes in cartilage thickness using detailed change maps and to examine if current methods for subregional analysis are able to capture the underlying cartilage changes. MRI images of 267 knees from 135 participants were acquired at baseline and 21-month follow-up and processed using a fully automatic framework for cartilage segmentation and quantification. The framework provides an anatomical coordinate system that allows for direct comparison across cartilage thickness maps. The reproducibility of this method was evaluated on 37 scan-rescan image pairs. In OA knees, an annualized thickness loss of 3.7% was observed in the medial femoral cartilage plate (MF) whereas subregional measurements varied between -9.0% (loss) and 1.6%. The largest changes were observed in the posterior part of the MF. In the medial tibial cartilage plate (MT), a thickness increase of 0.4% was observed whereas subregional measurements varied between -0.8% (loss) and 1.6%. In addition, notable differences in the patterns of cartilage change were observed between genders. This study indicated that the spatial changes, although highly heterogeneous, showed distinct patterns of cartilage thinning and cartilage thickening in both the MF and the MT. These patterns were not accurately reflected when thickness changes were averaged over large, predefined subregions as defined in current methods for subregional analysis.

  10. On Subregional Analysis of Cartilage Loss from Knee MRI

    PubMed Central

    Lillholm, Martin; Genant, Harry K.; Dam, Erik B.

    2013-01-01

    Objective: Understanding how knee cartilage is affected by osteoarthritis (OA) is critical in the development of sensitive biomarkers that may be used as surrogate endpoints in clinical trials. The objective of this study was to analyze longitudinal changes in cartilage thickness using detailed change maps and to examine if current methods for subregional analysis are able to capture the underlying cartilage changes. Materials and Methods: MRI images of 267 knees from 135 participants were acquired at baseline and 21-month follow-up and processed using a fully automatic framework for cartilage segmentation and quantification. The framework provides an anatomical coordinate system that allows for direct comparison across cartilage thickness maps. The reproducibility of this method was evaluated on 37 scan–rescan image pairs. Results: In OA knees, an annualized thickness loss of 3.7% was observed in the medial femoral cartilage plate (MF) whereas subregional measurements varied between −9.0% (loss) and 1.6%. The largest changes were observed in the posterior part of the MF. In the medial tibial cartilage plate (MT), a thickness increase of 0.4% was observed whereas subregional measurements varied between −0.8% (loss) and 1.6%. In addition, notable differences in the patterns of cartilage change were observed between genders. Conclusions: This study indicated that the spatial changes, although highly heterogeneous, showed distinct patterns of cartilage thinning and cartilage thickening in both the MF and the MT. These patterns were not accurately reflected when thickness changes were averaged over large, predefined subregions as defined in current methods for subregional analysis. PMID:26069655

  11. Loss of coolant analysis for the tower shielding reactor 2

    SciTech Connect

    Radcliff, T.D.; Williams, P.T.

    1990-06-01

    The operational limits of the Tower Shielding Reactor-2 (TSR-2) have been revised to account for placing the reactor in a beam shield, which reduces convection cooling during a loss-of-coolant accident (LOCA). A detailed heat transfer analysis was performed to set operating time limits which preclude fuel damage during a LOCA. Since a LOCA is survivable, the pressure boundary need not be safety related, minimizing seismic and inspection requirements. Measurements of reactor component emittance for this analysis revealed that aluminum oxidized in water may have emittance much higher than accepted values, allowing higher operating limits than were originally expected. These limits could be increased further with analytical or hardware improvements. 5 refs., 7 figs.

  12. Silicone rubber based magnetorheological elastomer: magnetic structure tested by means of neutron depolarization and magnetic force microscopy methods

    NASA Astrophysics Data System (ADS)

    Balasoiu, M.; Kozhevnikov, S. V.; Nikitenko, Yu V.; Iacobescu, G. E.; Bunoiu, M.; Bica, I.

    2017-05-01

    Magnetorheological elastomer samples (MREs) prepared using silicone rubber and spherical Fe microparticles have been investigated by means of neutron depolarization (ND) and magnetic force microscopy (MFM). From MFM analysis it was found the average diameter of the microparticles in the case of the isotropic samples to be 4.85 µm, while for the anisotropic ones, 5.1 µm. It was applied and examined the neutron depolarization process in function the microparticle concentration variation and the sample anisotropy.

  13. Images of depolarization power and retardance to study stages of dysplasia in human cervical tissues

    NASA Astrophysics Data System (ADS)

    Mozumder, Meghdoot; Jagtap, Jaidip; Shukla, Prashant; Pradhan, Asima

    2011-03-01

    Optical techniques, especially the ones related to light scattering, has been seen to capture morphological changes, such as increase in size and density of nuclei in cells. Mueller imaging of the epithelium and basal layer based on polarized elastic scattering in human cervical tissue sections has been used to identify the dysplastic conditions of the human cervix. The effect of dysplasia strongly manifests in the depolarization power and retardance, which differs significantly in normal and dysplastic tissues sections. Principal Component Analysis (PCA) of the depolarization power images derived from polar decomposition of Mueller matrices of 36 patients clearly identifies the tissue region responsible for clear discrimination between the diseased and normal tissues. Significantly, the principal components are found to be sensitive in discriminating normal cervical tissue and the two different stages of dysplastic conditions grade I (GD1) and grade II (GD2) and provide cut-off depolarization values for each of these stages.Though the depolarization values of GD1 are quite random as compared to normal and GD2 states, PCA is able to effectively separate it out by capturing subtle changes in the depolarization values.It is worth noting that in the GD2 stage concentration of cells is high in the epithelial region near the basal layer than the epithelium layer near the surface though this difference between these two regions is not as significant as in GD1. Interestingly, this phenomenon is well reflected in the depolarization values, which PCA uses effectively to segment GD1 and GD2 into different clusters. Retardance values show little variation along the stroma. However, covariance matrix images of dysplastic and normal are able to capture depletion of retardance below the basal layer due to progressive disruption of collagen network in dysplasia.

  14. Light depolarization measurements in malaria: A new job for an old friend.

    PubMed

    Rebelo, Maria; Tempera, Carolina; Bispo, Claudia; Andrade, Claudia; Gardner, Rui; Shapiro, Howard M; Hänscheid, Thomas

    2015-05-01

    The use of flow cytometry in malaria research has increased over the last decade. Most approaches use nucleic acid stains to detect parasite DNA and RNA and require complex multi-color, multi-parameter analysis to reliably detect infected red blood cells (iRBCs). We recently described a novel and simpler approach to parasite detection based on flow cytometric measurement of scattered light depolarization caused by hemozoin (Hz), a pigment formed by parasite digestion of hemoglobin in iRBCs. Depolarization measurement by flow cytometry was described in 1987; however, patent issues restricted its use to a single manufacturer's hematology analyzers until 2009. Although we recently demonstrated that depolarization measurement of Hz, easily implemented on a bench top flow cytometer (Cyflow), provided useful information for malaria work, doubts regarding its application and utility remain in both the flow cytometry and malaria communities, at least in part because instrument manufacturers do not offer the option of measuring depolarized scatter. Under such circumstances, providing other researchers with guidance as to how to do this seemed to offer the most expeditious way to resolve the issue. We accordingly examined how several commercially available flow cytometers (CyFlow SL, MoFLo, Attune and Accuri C6) could be modified to detect depolarization due to the presence of free Hz on solution, or of Hz in leukocytes or erythrocytes from rodent or human blood. All were readily adapted, with substantially equivalent results obtained with lasers emitting over a wide wavelength range. Other instruments now available may also be modifiable for Hz measurement. Cytometric detection of Hz using depolarization is useful to study different aspects of malaria. Adding additional parameters, such as DNA content and base composition and RNA content, can demonstrably provide improved accuracy and sensitivity of parasite detection and characterization, allowing malaria researchers and

  15. [Cortical spreading depolarization: a new pathophysiological mechanism in neurological diseases].

    PubMed

    Sánchez-Porras, Renán; Robles-Cabrera, Adriana; Santos, Edgar

    2014-05-20

    Cortical spreading depolarization is a wave of almost complete depolarization of the neuronal and glial cells that occurs in different neurological diseases such as migraine with aura, subarachnoid hemorrhage, intracerebral hemorrhage, head trauma and stroke. These depolarization waves are characterized by a change in the negative potential with an amplitude between -10 and -30mV, duration of ∼1min and changes in the ion homeostasis between the intra- and extracellular space. This results in neuronal edema and dendritic distortion. Under pathologic states of hypoperfusion, cortical spreading depolarization can produce oxidative stress, worsen hypoxia and induce neuronal death. This is due to intense arterial vasoconstriction produced by an inverse response called spreading ischemia. Only in the last years there has been an electrophysiological confirmation of cortical spreading depolarization in human brains. Occurrence of cortical spreading depolarization has been associated with worse outcome in patients. Currently, increased knowledge regarding the pathophysiologic mechanisms supports the hypothetical correlation of cortical spreading depolarization with brain damage in humans. There are diverse therapeutic alternatives that promise inhibition of cortical spreading depolarization and subsequent better outcomes. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  16. Depolarization of diffusely reflecting man-made objects.

    PubMed

    DeBoo, Brian J; Sasian, Jose M; Chipman, Russell A

    2005-09-10

    The polarization properties of light scattered or diffusely reflected from seven different man-made samples are studied. For each diffusely reflecting sample an in-plane Mueller matrix bidirectional reflectance distribution function is measured at a fixed bistatic angle using a Mueller matrix imaging polarimeter. The measured profile of depolarization index with changing scattering geometry for most samples is well approximated by an inverted Gaussian function. Depolarization is minimum for specular reflection and increases asymptotically in a Gaussian fashion as the angles of incidence and scatter increase. Parameters of the Gaussian profiles fitted to the depolarization data are used to compare samples. The dependence of depolarization on the incident polarization state is compared for each Stokes basis vector: horizontal, vertical, 45 degrees, 135 degrees, and right- and left-circular polarized light. Linear states exhibit similar depolarization profiles that typically differ in value by less than 0.06 (where 1.0 indicates complete depolarization). Circular polarization states are depolarized more than linear states for all samples tested, with the output degree of polarization reduced from that of linear states by as much as 0.15. The depolarization difference between linear and circular states varies significantly between samples.

  17. Q(M) and the depolarization index scalar metrics.

    PubMed

    Espinosa-Luna, Rafael; Bernabeu, Eusebio; Atondo-Rubio, Gelacio

    2008-04-01

    A depolarization scalar metric for Mueller matrices, named Q(M), is derived from the degree of polarization. Q(M) has been recently reported, and it has been deduced from the nine bilinear constraints between the sixteen elements of the Mueller-Jones matrix. We discuss the relations between Q(M) and the depolarization index.

  18. Simple analytic formula for the strength of spin depolarizing resonance

    SciTech Connect

    Lee, S.Y.

    1985-01-01

    A simple analytic formula is derived to explain the periodicity of spin depolarizing resonance. The spin depolarizing resonance strengths of CPS and SPS at CERN and the lattices of meson factory at TRIUMF are used to compare with the analytic formula.

  19. Analysis of Loss-of-Coolant Accidents in the NBSR

    SciTech Connect

    Baek J. S.; Cheng L.; Diamond, D.

    2014-05-23

    This report documents calculations of the fuel cladding temperature during loss-of-coolant accidents in the NBSR. The probability of a pipe failure is small and procedures exist to minimize the loss of water and assure emergency cooling water flows into the reactor core during such an event. Analysis in the past has shown that the emergency cooling water would provide adequate cooling if the water filled the flow channels within the fuel elements. The present analysis is to determine if there is adequate cooling if the water drains from the flow channels. Based on photographs of how the emergency water flows into the fuel elements from the distribution pan, it can be assumed that this water does not distribute uniformly across the flow channels but rather results in a liquid film flowing downward on the inside of one of the side plates in each fuel element and only wets the edges of the fuel plates. An analysis of guillotine breaks shows the cladding temperature remains below the blister temperature in fuel plates in the upper section of the fuel element. In the lower section, the fuel plates are also cooled by water outside the element that is present due to the hold-up pan and temperatures are lower than in the upper section. For small breaks, the simulation results show that the fuel elements are always cooled on the outside even in the upper section and the cladding temperature cannot be higher than the blister temperature. The above results are predicated on assumptions that are examined in the study to see their influence on fuel temperature.

  20. Loss analysis of the thermodynamic cycle of magnetic heat pumps

    NASA Astrophysics Data System (ADS)

    Chen, F. C.; Murphy, R. W.; Mei, V. C.; Chen, G. L.; Lue, J. W.; Lubell, M. S.

    1991-02-01

    The needs for developing non-ozone-depleting, no-greenhouse-effect heat pump systems and for exploring the potential of new high-temperature superconducting materials have prompted a renewed interest in the study of magnetic heat pumps. The new materials can provide the high magnetic field that an effective superconducting magnetic heat pump requires, and magnetic heat pumps do not use freon for a working fluid. Traditionally, magnetic heat pump concepts have been successfully developed and used for refrigeration applications at temperatures near absolute zero degree. In these cases, a temperature lift of a few degrees in a cryogenic environment is sufficient and can be easily achieved by a simple magnetic heat pump cycle. The working media are usually the chemical compounds of gadolinium. To extend magnetic heat pumping to other temperature ranges and other types of applications in which the temperature lift is more than just a few degrees requires more involved cycle processes dependent upon the thermomagnetic properties of the working media and the availability of a high magnetic field. This report documents our efforts to study the thermophysics of magnetic heat pumps, including a survey of literature, a study of thermodynamic cycles and cycle thermal losses, and an analysis of pulse magnets. The regenerative cycle has been identified as the most efficient, with a maximum of 42 percent loss in coefficient of performance at 260 K cooling temperature and a maximum of 15 percent loss in capacity at 232 K cooling temperature for the constant field (magnetic Ericsson) cycle, between 200 and 320 K, as compared with the ideal regenerative cycle with gadolinium as the core material.

  1. Depolarization of an uncollimated laser beam in a turbulent medium

    NASA Technical Reports Server (NTRS)

    Chang, F. C.; Mott, H.; Webb, W. E.

    1973-01-01

    The depolarization of a beam wave, with Gaussian intensity distribution and arbitrary divergence, propagating in a turbulent medium is considered. The correlation function of the depolarized component of the beam is determined. The mean-square depolarization fluctuation is then determined for a medium characterized by a Kolmogorov spectrum. If the beam is assumed to be collimated, this expression reduces to that of Collett and Alferness; if the plane-wave limiting case of the Gaussian beam is taken, the results in this paper agree with those of Strohbehn. The results show that off the beam axis the depolarization can be greater than for the plane wave, and that near the beam focal point the depolarization may decrease by orders of magnitude.

  2. Role of magnesium in the reduction of ischemic depolarization and lesion volume after experimental subarachnoid hemorrhage.

    PubMed

    van den Bergh, Walter M; Zuur, J Karel; Kamerling, Niels A; van Asseldonk, Jan Thies H; Rinkel, Gabriël J E; Tulleken, Cornelis A F; Nicolay, Klaas

    2002-08-01

    Ischemia-induced tissue depolarizations probably play an important role in the pathophysiology of cerebral ischemia caused by parent vessel occlusion. Their role in ischemia caused by subarachnoid hemorrhage (SAH) remains to be investigated. The authors determined whether ischemic depolarizations (IDs) or cortical spreading depressions (CSDs) occur after SAH, and how these relate to the extent of tissue injury measured on magnetic resonance (MR) images. In addition, they assessed whether administration of MgSO4 reduces depolarization time and lesion volume. By means of the endovascular suture model, experimental SAH was induced in 52 rats, of which 37 were appropriate for analysis, including four animals that underwent sham operations. Before induction of SAH, serum Mg++ levels were measured and 90 mg/kg intravascular MgSO4 or saline was given. Extracellular direct current potentials were continuously recorded from six Ag/AgCl electrodes, before and up to 90 minutes following SAH, after which serum Mg++ levels were again measured. Next, animals were transferred to the MR imaging magnet for diffusion-weighted (DW) MR imaging. Depolarization times per electrode were averaged to determine a mean depolarization time per animal. No depolarizations occurred in sham-operated animals. Ischemic depolarizations occurred at all electrodes in all animals after SAH. Only two animals displayed a single spreading depression-like depolarization. The mean duration of the ID time was 41 +/- 25 minutes in the saline-treated controls and 31 +/- 30 minutes in the Mg++-treated animals (difference 10 minutes: p = 0.31). Apparent diffusion coefficient (ADC) maps of tissue H2O, obtained using DW images approximately 2.5 hours after SAH induction, demonstrated hypointensities in both hemispheres, but predominantly in the ipsilateral cortex. No ADC abnormalities were found in sham-operated animals. The mean lesion volume, as defined on the basis of a significant ADC reduction, was 0.32 +/- 0

  3. Analysis of frequency loss as a prognostic factor in idiopathic sensorineural hearing loss.

    PubMed

    Jun, Hyung Jin; Chang, Jiwon; Im, Gi Jung; Kwon, Soon-Young; Jung, Hakhyun; Choi, June

    2012-06-01

    The combination of systemic steroids with intratympanic dexamethasone injection (ITDI) did not result in significantly different outcomes from steroid treatment only and did not have any additional beneficial effects. To evaluate hearing recovery in idiopathic sudden sensorineural hearing loss (ISSNHL) according to frequency and to compare treatment responses between patients treated with systemic steroids and systemic steroids with ITDI. Ninety-nine patients with ISSNHL were selected to participate in the study by a retrospective medical chart review. Patients were divided into two groups, systemic steroid treatment only and systemic steroid with adjunctive ITDI. Hearing recovery was evaluated by pure tone audiometry (PTA). All patients underwent PTA examination before treatment and after 3 months. Thresholds were analyzed by frequency along with other factors. Low frequency hearing loss responded better than high frequency loss to PTA. When we analyzed pure tone audiogram patterns, all patterns except for the descending type showed better improvement in patients with lower frequency hearing loss than in patients with higher frequency hearing loss.

  4. Impacts of depolarization calibration methods on cloud phase interpretation at Eureka during 2013 and 2014 CRL lidar measurement campaigns

    NASA Astrophysics Data System (ADS)

    McCullough, E. M.; Perro, C. W.; Gamage, S. M.; Hopper, J.; Sica, R. J.; Duck, T.; Walker, K. A.; Drummond, J. R.

    2014-12-01

    The radiative behaviour of clouds is dependent on cloud particle phase. Water droplets can exist in temperatures well below 0° C for extended periods. Lidar depolarization measurements allow liquid and solid states to be differentiated in individual clouds at high spatial-temporal resolution. The 2012, 2013 and 2014 Canadian Arctic ACE Validation Campaigns in Eureka, Nunavut, Canada (80°N, 86°W) provided an opportunity to make extensive depolarization measurements using the CANDAC Rayleigh-Mie-Raman Lidar (CRL) in the troposphere.To date, most calibration methods in the literature are applicable to lidars which do not have non-ideal polarizing optics upstream of the polarizing analyzers in the receiver. We demonstrate a more complete matrix algebra calibration of the CRL to take the extra optics from six upstream lidar channels into account.Differences in depolarization parameter from 2013 and 2014 measurements show the advantage of the more extensive calibration for this lidar compared to the simpler traditional approach. The largest differences are found for depolarization parameter values around d = 0.50 (corresponding to δ = 0.33). Depolarization ratio values of δ = 0.2 to 0.3 are generally taken to be the cutoff between interpretations of ice (higher δ) or water (lower δ), and many CRL measurements lie in this particularly diagnostic range. An uncertainty analysis becomes important when extending the depolarization parameters to interpretation of the clouds in the atmosphere above Eureka.

  5. Depolarization of MNOS structures in the regime of dispersion transport

    NASA Astrophysics Data System (ADS)

    Raikerus, P. A.; Gurtov, V. A.

    1991-01-01

    A theory of isothermal depolarization of insulators based on dispersive transport through traps (exponentially distributed in energy) is developed. Equations for the dependence of flat-band voltage on time have been obtained. It is shown that the depolarization process takes place during a sufficiently long time (over about six decades of time). Equations for the "energy activation" of the depolarization process increasing with time and decreasing with temperature and electric field have been obtained. Experimental data for MNOS structures are explained on the basis of the dispersive transport theory.

  6. Spreading convulsions, spreading depolarization and epileptogenesis in human cerebral cortex

    PubMed Central

    Major, Sebastian; Pannek, Heinz-Wolfgang; Woitzik, Johannes; Scheel, Michael; Wiesenthal, Dirk; Martus, Peter; Winkler, Maren K.L.; Hartings, Jed A.; Fabricius, Martin; Speckmann, Erwin-Josef; Gorji, Ali

    2012-01-01

    Spreading depolarization of cells in cerebral grey matter is characterized by massive ion translocation, neuronal swelling and large changes in direct current-coupled voltage recording. The near-complete sustained depolarization above the inactivation threshold for action potential generating channels initiates spreading depression of brain activity. In contrast, epileptic seizures show modest ion translocation and sustained depolarization below the inactivation threshold for action potential generating channels. Such modest sustained depolarization allows synchronous, highly frequent neuronal firing; ictal epileptic field potentials being its electrocorticographic and epileptic seizure its clinical correlate. Nevertheless, Leão in 1944 and Van Harreveld and Stamm in 1953 described in animals that silencing of brain activity induced by spreading depolarization changed during minimal electrical stimulations. Eventually, epileptic field potentials were recorded during the period that had originally seen spreading depression of activity. Such spreading convulsions are characterized by epileptic field potentials on the final shoulder of the large slow potential change of spreading depolarization. We here report on such spreading convulsions in monopolar subdural recordings in 2 of 25 consecutive aneurismal subarachnoid haemorrhage patients in vivo and neocortical slices from 12 patients with intractable temporal lobe epilepsy in vitro. The in vitro results suggest that γ-aminobutyric acid-mediated inhibition protects from spreading convulsions. Moreover, we describe arterial pulse artefacts mimicking epileptic field potentials in three patients with subarachnoid haemorrhage that ride on the slow potential peak. Twenty-one of the 25 subarachnoid haemorrhage patients (84%) had 656 spreading depolarizations in contrast to only three patients (12%) with 55 ictal epileptic events isolated from spreading depolarizations. Spreading depolarization frequency and depression

  7. Realizing controllable depolarization in photonic quantum-information channels

    SciTech Connect

    Shaham, A.; Eisenberg, H. S.

    2011-02-15

    Controlling the depolarization of light is a long-standing open problem. In recent years, many demonstrations have used the polarization of single photons to encode quantum information. The depolarization of these photons is equivalent to the decoherence of the quantum information they encode. We present schemes for building various depolarizing channels with controlled properties using birefringent crystals. Three such schemes are demonstrated, and their effects on single photons are shown by quantum process tomography to be in good agreement with a theoretical model.

  8. Molecular anisotropy effects in carbon K-edge scattering: depolarized diffuse scattering and optical anisotropy

    SciTech Connect

    Stone, Kevin H.

    2014-07-14

    Some polymer properties, such as conductivity, are very sensitive to short- and intermediate-range orientational and positional ordering of anisotropic molecular functional groups, and yet means to characterize orientational order in disordered systems are very limited. We demonstrate that resonant scattering at the carbon K-edge is uniquely sensitive to short-range orientation correlations in polymers through depolarized scattering at high momentum transfers, using atactic polystyrene as a well-characterized test system. Depolarized scattering is found to coexist with unpolarized fluorescence, and to exhibit pronounced anisotropy. We also quantify the spatially averaged optical anisotropy from low-angle reflectivity measurements, finding anisotropy consistent with prior visible, x-ray absorption, and theoretical studies. The average anisotropy is much smaller than that in the depolarized scattering and the two have different character. Both measurements exhibit clear spectral signatures from the phenyl rings and the polyethylene-like backbone. Discussion focuses on analysis considerations and prospects for using this depolarized scattering for studies of disorder in soft condensed matter.

  9. Nur77 is differentially modified in PC12 cells upon membrane depolarization and growth factor treatment.

    PubMed Central

    Hazel, T G; Misra, R; Davis, I J; Greenberg, M E; Lau, L F

    1991-01-01

    The rat pheochromocytoma cell line PC12 can be induced by growth factors to undergo proliferation and neuronal differentiation. These cells also have excitable membranes that can be depolarized by neurotransmitters or elevated levels of extracellular KCl. Treatment of PC12 cells with growth factors or membrane-depolarizing agents rapidly activates the expression of specific genes whose products are thought to mediate the subsequent biological responses. One such gene, nur77, is a member of the steroid and thyroid hormone receptor gene superfamily. We have identified the Nur77 protein and shown that it is synthesized rapidly and transiently in PC12 cells following stimulation, has a short half-life of 30 to 40 min, and is located in both the nucleus and the cytoplasm. Nur77 is posttranslationally modified, primarily by phosphorylation on serine residues. Phosphopeptide analysis reveals that Nur77 is modified differently upon membrane depolarization than after treatment with growth factors. We hypothesize that the activity of Nur77 is regulated by both differential gene expression and posttranslational modification and that these modes of regulation contribute to distinct downstream responses specific to membrane depolarization and growth factor treatment. Images PMID:1645447

  10. Molecular anisotropy effects in carbon K-edge scattering: Depolarized diffuse scattering and optical anisotropy

    NASA Astrophysics Data System (ADS)

    Stone, Kevin H.; Kortright, Jeffrey B.

    2014-09-01

    Some polymer properties, such as conductivity, are very sensitive to short- and intermediate-range orientational and positional ordering of anisotropic molecular functional groups, and yet means to characterize orientational order in disordered systems are very limited. We demonstrate that resonant scattering at the carbon K edge is uniquely sensitive to short-range orientation correlations in polymers through depolarized scattering at high momentum transfers, using atactic polystyrene as a well-characterized test system. Depolarized scattering is found to coexist with unpolarized fluorescence and to exhibit pronounced anisotropy. We also quantify the spatially averaged optical anisotropy from low-angle reflectivity measurements, finding anisotropy consistent with prior visible, x-ray absorption, and theoretical studies. The average anisotropy is much smaller than that in the depolarized scattering and the two have different character. Both measurements exhibit clear spectral signatures from the phenyl rings and the polyethylenelike backbone. Discussion focuses on analysis considerations and prospects for using this depolarized scattering for studies of disorder in soft condensed matter.

  11. Collisional angular momentum depolarization of OH(A) and NO(A) by Ar: a comparison of mechanisms.

    PubMed

    Brouard, M; Chadwick, H; Chang, Y-P; Eyles, C J; Aoiz, F J; Kłos, J

    2011-08-28

    This paper discusses the contrasting mechanisms of collisional angular momentum depolarization of OH(A(2)Σ(+)) and NO(A(2)Σ(+)) by Ar. New experimental results are presented for the collisional depolarization of OH(A) + Ar under both thermal and superthermal collision conditions, including cross sections for loss of both angular momentum orientation and alignment. Previous work on the two systems is summarized. It is shown that NO(A) + Ar depolarization is dominated by impulsive events in which the projection of the angular momentum, j, along the kinematic apse, a, is nearly conserved, and in which the majority of the trajectories can be described as "nearside." By contrast, at the relatively low collision energies sampled at 300 K, OH(A) + Ar depolarization is dominated by attractive collisions, which show a preponderance of "farside" trajectories. There is also evidence for very long-lived, complex type trajectories in which OH(A) and Ar orbit each other for several rotational periods prior to separation. Nevertheless, there is still a clear preference for conservation of the projection of j along the kinematic apse for both elastic and inelastic collisions. Experimental and theoretical results reveal that, as the collision energy is raised, the depolarization of OH(A) by Ar becomes more impulsive-like in nature.

  12. Quantitative analysis of incipient mineral loss in hard tissues

    NASA Astrophysics Data System (ADS)

    Matvienko, Anna; Mandelis, Andreas; Hellen, Adam; Jeon, Raymond; Abrams, Stephen; Amaechi, Bennett

    2009-02-01

    A coupled diffuse-photon-density-wave and thermal-wave theoretical model was developed to describe the biothermophotonic phenomena in multi-layered hard tissue structures. Photothermal Radiometry was applied as a safe, non-destructive, and highly sensitive tool for the detection of early tooth enamel demineralization to test the theory. Extracted human tooth was treated sequentially with an artificial demineralization gel to simulate controlled mineral loss in the enamel. The experimental setup included a semiconductor laser (659 nm, 120 mW) as the source of the photothermal signal. Modulated laser light generated infrared blackbody radiation from teeth upon absorption and nonradiative energy conversion. The infrared flux emitted by the treated region of the tooth surface and sub-surface was monitored with an infrared detector, both before and after treatment. Frequency scans with a laser beam size of 3 mm were performed in order to guarantee one-dimensionality of the photothermal field. TMR images showed clear differences between sound and demineralized enamel, however this technique is destructive. Dental radiographs did not indicate any changes. The photothermal signal showed clear change even after 1 min of gel treatment. As a result of the fittings, thermal and optical properties of sound and demineralized enamel were obtained, which allowed for quantitative differentiation of healthy and non-healthy regions. In conclusion, the developed model was shown to be a promising tool for non-invasive quantitative analysis of early demineralization of hard tissues.

  13. Uncertainty analysis for a field-scale P loss model

    USDA-ARS?s Scientific Manuscript database

    Models are often used to predict phosphorus (P) loss from agricultural fields. While it is commonly recognized that model predictions are inherently uncertain, few studies have addressed prediction uncertainties using P loss models. In this study we assessed the effect of model input error on predic...

  14. Neuronal Depolarization Drives Increased Dopamine Synaptic Vesicle Loading via VGLUT.

    PubMed

    Aguilar, Jenny I; Dunn, Matthew; Mingote, Susana; Karam, Caline S; Farino, Zachary J; Sonders, Mark S; Choi, Se Joon; Grygoruk, Anna; Zhang, Yuchao; Cela, Carolina; Choi, Ben Jiwon; Flores, Jorge; Freyberg, Robin J; McCabe, Brian D; Mosharov, Eugene V; Krantz, David E; Javitch, Jonathan A; Sulzer, David; Sames, Dalibor; Rayport, Stephen; Freyberg, Zachary

    2017-08-30

    The ability of presynaptic dopamine terminals to tune neurotransmitter release to meet the demands of neuronal activity is critical to neurotransmission. Although vesicle content has been assumed to be static, in vitro data increasingly suggest that cell activity modulates vesicle content. Here, we use a coordinated genetic, pharmacological, and imaging approach in Drosophila to study the presynaptic machinery responsible for these vesicular processes in vivo. We show that cell depolarization increases synaptic vesicle dopamine content prior to release via vesicular hyperacidification. This depolarization-induced hyperacidification is mediated by the vesicular glutamate transporter (VGLUT). Remarkably, both depolarization-induced dopamine vesicle hyperacidification and its dependence on VGLUT2 are seen in ventral midbrain dopamine neurons in the mouse. Together, these data suggest that in response to depolarization, dopamine vesicles utilize a cascade of vesicular transporters to dynamically increase the vesicular pH gradient, thereby increasing dopamine vesicle content. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. The Pathophysiological Mechanism Underlying Brugada Syndrome. Depolarization versus Repolarization

    PubMed Central

    Wilde, Arthur A.M.; Postema, Pieter G.; Di Diego, José M.; Viskin, Sami; Morita, Hiroshi; Fish, Jeffrey M.; Antzelevitch, Charles

    2010-01-01

    This Point/Counterpoint presents a scholarly debate of the mechanisms underlying the electrocardiographic and arrhythmic manifestations of Brugada syndrome (BrS), exploring in detail the available evidence in support of the repolarization vs. depolarization hypothesis. PMID:20659475

  16. Analysis of Power Converter Losses in Vector Control System of a Self-Excited Induction Generator

    NASA Astrophysics Data System (ADS)

    Bašić, Mateo; Vukadinović, Dinko; Polić, Miljenko

    2014-03-01

    This paper provides analysis of losses in the hysteresis-driven three-phase power converter with IGBTs and free-wheeling diodes. The converter under consideration is part of the self-excited induction generator (SEIG) vector control system. For the analysis, the SEIG vector control system is used in which the induction generator iron losses are taken into account. The power converter losses are determined by using a suitable loss estimation algorithm reported in literature. The chosen algorithm allows the power converter losses to be determined both by type (switching/conduction losses) and by converter component (IGBT/diode losses). The overall power converter losses are determined over wide ranges of rotor speed, dc-link voltage and load resistance, and subsequently used for offline correction of the overall control system's losses (efficiency) obtained through control system simulations with an ideal power converter. The control system's efficiency values obtained after the correction are compared with the measured values.

  17. Two muscarinic depolarizing mechanisms in mammalian sympathetic neurons.

    PubMed

    Hashiguchi, T; Kobayashi, H; Tosaka, T; Libet, B

    1982-06-24

    A voltage-sensitive outward membrane current ('M') and a consequent change in conductance (delta G) appear with a slow time-constant, in principal neurons of rabbit superior cervical ganglion (SCG), only when membrane potentials (Vm) are depolarized to less than -60 mV. Effects of muscarine on the voltage-current curves indicate that, in this depolarized range of less than -60 mV, suppression of M-current could contribute a muscarinic depolarization accompanied by a decrease in G; but that, at all Vms tested (about -90 to -40 mV), there is an additional larger muscarinic depolarization with no delta G. Thus, the muscarinic depolarizing response and the equivalent slow excitatory postsynaptic potential in the rabbit SCG may consist of two different components: one is due to the suppression of M-current and is substantial only in the depolarized range; the other is probably mediated via an intracellular increase in cyclic GMP and can account for most or all of the response at Vms more negative than -55 mV.

  18. Depolarization of light by rough surface of scattering phantoms

    NASA Astrophysics Data System (ADS)

    Tchvialeva, Lioudmila; Markhvida, Igor; Lee, Tim K.; Doronin, Alexander; Meglinski, Igor

    2013-02-01

    The growing interest in biomedical optics to the polarimetric methods push researchers to better understand of light depolarization during scattering in and on the surface of biological tissues. Here we study the depolarization of light propagated in silicone phantoms. The phantoms with variety of surface roughness and bulk optical properties are designed to imitate human skin. Free-space speckle patterns in parallel (III) and perpendicular (I⊥) direction in respect to incident polarization are used to get the depolarization ratio of backscattered light DR = (III - I⊥)/( III + I⊥). The Monte Carlo model developed in house is also applied to compare simulated DR with experimentally measured. DR dependence on roughness, concentration and size of scattering particles is analysed. A weak depolarization and negligible response to scattering of the medium are observed for phantoms with smooth surfaces, whereas for the surface roughness in order to the mean free path the depolarization ratio decreases and reveals dependence on the bulk scattering coefficient. In is shown that the surface roughness could be a key factor triggering the ability of tissues' characterization by depolarization ratio.

  19. Physiogenomic analysis of weight loss induced by dietary carbohydrate restriction

    PubMed Central

    Ruaño, Gualberto; Windemuth, Andreas; Kocherla, Mohan; Holford, Theodore; Fernandez, Maria Luz; Forsythe, Cassandra E; Wood, Richard J; Kraemer, William J; Volek, Jeff S

    2006-01-01

    Background Diets that restrict carbohydrate (CHO) have proven to be a successful dietary treatment of obesity for many people, but the degree of weight loss varies across individuals. The extent to which genetic factors associate with the magnitude of weight loss induced by CHO restriction is unknown. We examined associations among polymorphisms in candidate genes and weight loss in order to understand the physiological factors influencing body weight responses to CHO restriction. Methods We screened for genetic associations with weight loss in 86 healthy adults who were instructed to restrict CHO to a level that induced a small level of ketosis (CHO ~10% of total energy). A total of 27 single nucleotide polymorphisms (SNPs) were selected from 15 candidate genes involved in fat digestion/metabolism, intracellular glucose metabolism, lipoprotein remodeling, and appetite regulation. Multiple linear regression was used to rank the SNPs according to probability of association, and the most significant associations were analyzed in greater detail. Results Mean weight loss was 6.4 kg. SNPs in the gastric lipase (LIPF), hepatic glycogen synthase (GYS2), cholesteryl ester transfer protein (CETP) and galanin (GAL) genes were significantly associated with weight loss. Conclusion A strong association between weight loss induced by dietary CHO restriction and variability in genes regulating fat digestion, hepatic glucose metabolism, intravascular lipoprotein remodeling, and appetite were detected. These discoveries could provide clues to important physiologic adaptations underlying the body mass response to CHO restriction. PMID:16700901

  20. Subcutaneous fat loss is greater than visceral fat loss with diet and exercise, weight-loss promoting drugs and bariatric surgery: a critical review and meta-analysis.

    PubMed

    Merlotti, C; Ceriani, V; Morabito, A; Pontiroli, A E

    2017-05-01

    Aim of this review is to compare visceral and subcutaneous fat loss with all available strategies (diet and exercise, weight-loss promoting agents and bariatric surgery). Eighty-nine studies, all full papers, were analyzed to evaluate visceral and subcutaneous fat changes, measured through ultrasound, computerized tomography, magnetic resonance imaging and expressed as thickness, weight, area and volume. Studies were included in a meta-analysis (random-effects model). Intervention effect (absolute and percent changes of visceral and subcutaneous fat) was expressed as standardized mean differences, with 95% confidence intervals. Publication bias was formally assessed. The result was that subcutaneous fat was greater than visceral fat when measured as area, volume and weight, not as thickness; decrease of subcutaneous fat was greater than visceral fat when measured as area, volume and weight, not as thickness; percent decrease of visceral fat was always greater than percent decrease of subcutaneous fat, with no differences between different strategies. No intervention preferentially targets visceral fat. Basal visceral fat depots are smaller than basal subcutaneous fat depots. Visceral fat loss is linked to subcutaneous fat loss. With all strategies, percent decrease of visceral fat prevails on subcutaneous fat loss.

  1. Analysis of beam loss mechanism in the Project X linac

    SciTech Connect

    Carneiro, J.-P.; Lebedev, V.; Nagaitsev, S.; Ostiguy, J.-F.; Solyak, N.; /Fermilab

    2011-03-01

    Minimization of the beam losses in a multi-MW H{sup -} linac such as ProjectX to a level below 1 W/m is a challenging task. The impact of different mechanism of beam stripping, including stripping in electric and magnetic fields, residual gas, blackbody radiation and intra-beam stripping, is analyzed. Other sources of beam losses are misalignements of beamline elements and errors in RF fields and phases. We present in this paper requirements for dynamic errors and correction schemes to keep beam losses under control.

  2. Analysis ob beam losses at PSR (Proton Storage Ring)

    SciTech Connect

    Macek, R.J.; Fitzgerald, D.H.; Hutson, R.L.; Plum, M.A.; Thiessen, H.A.

    1988-01-01

    Beam losses and the resulting component activation at the Los Alamos Proton Storage Ring (PSR) have limited operating currents to about 30..mu..A average at a repetition rate of 15 Hz. Loss rates were found to be approximately proportional to the circulating current and can be understood by a detailed accounting of emittance growth in the two step injection process along with Coulomb scattering of the stored beam during multiple traversals of the injection foil. Calculations and simulations of the losses are in reasonable agreement with measurements.

  3. Photographic Analysis Technique for Assessing External Tank Foam Loss Events

    NASA Technical Reports Server (NTRS)

    Rieckhoff, T. J.; Covan, M.; OFarrell, J. M.

    2001-01-01

    A video camera and recorder were placed inside the solid rocket booster forward skirt in order to view foam loss events over an area on the external tank (ET) intertank surface. In this Technical Memorandum, a method of processing video images to allow rapid detection of permanent changes indicative of foam loss events on the ET surface was defined and applied to accurately count, categorize, and locate such events.

  4. Model parameter uncertainty analysis for annual field-scale P loss model

    USDA-ARS?s Scientific Manuscript database

    Phosphorous (P) loss models are important tools for developing and evaluating conservation practices aimed at reducing P losses from agricultural fields. All P loss models, however, have an inherent amount of uncertainty associated with them. In this study, we conducted an uncertainty analysis with ...

  5. Model parameter uncertainty analysis for an annual field-scale phosphorus loss model

    USDA-ARS?s Scientific Manuscript database

    Phosphorous (P) loss models are important tools for developing and evaluating conservation practices aimed at reducing P losses from agricultural fields. All P loss models, however, have an inherent amount of uncertainty associated with them. In this study, we conducted an uncertainty analysis with ...

  6. Analysis of caloric test responses in sudden hearing loss.

    PubMed

    Shih, Cheng-Ping; Chou, Yu-Ching; Chen, Hsin-Chien; Lee, Jih-Chin; Chu, Yueng-Hsiang; Wang, Chih-Hung

    2017-02-01

    Sudden sensorineural hearing loss is characterized by a rapid-onset hearing loss that develops within 3 days. Vertigo may also be present. We conducted a retrospective study to investigate whether the severity of a loss of caloric function is associated with the initial hearing loss and with hearing recovery. Our study population was made up of 135 patients-67 men and 68 women, aged 25 to 71 years (mean: 50.9)-with sudden sensorineural hearing loss who had undergone bithermal caloric testing. We compared various patient factors according to patients' hearing level and their response to caloric testing. We also analyzed the canal paresis (CP) value in patients with an abnormal caloric response according to three factors: disease severity, vertigo, and hearing recovery, and we evaluated the correlation between the loss of caloric function and hearing outcomes. We found that an abnormal caloric response was significantly associated with a profound hearing loss at presentation, the presence of vertigo, and poor hearing recovery. Among patients with an abnormal caloric response, the CP value was significantly correlated with hearing recovery (r = 0.503, p = 0.001). Poor hearing recovery was seen in 80% of patients with a CP value of ≥40% but in only 25% of patients with a value of <40%; in addition, the degree of hearing recovery was worse in the patients with a CP value of ≥40% (p = 0.002). We conclude that a CP value of ≥40% is a significant prognostic factor for an unfavorable treatment outcome.

  7. Linear harmonic analysis for Stirling machines and second law analysis of four important losses

    SciTech Connect

    Chen, N.C.J.; Griffin, F.P.; West, C.D.

    1984-01-01

    A simple thermodynamic theory for Stirling machine performance has been developed. By representing variables in terms of harmonic oscillations and representing the nonharmonic terms in the conservation equations with truncated Fourier series, the equations can be solved in a semi-closed form, leading to a better understanding of Stirling engine behavior. The theory further includes a Second Law analysis; therefore, the efficiency and power losses resulting from effects of adiabatic cylinders, transient heat transfer, pressure drop, and seal leakage can be allocated unambiguously, and the degree of loss coupling can be assessed. 9 references.

  8. Linear harmonic analysis for Stirling machines and second law analysis of four important losses

    SciTech Connect

    Chen, N.C.J.; Griffin, F.P.; West, C.D.

    1984-08-01

    A simple thermodynamic theory for Stirling machine performance has been developed. By representing variables in terms of harmonic oscillations and representing the nonharmonic terms in the conservation equations with truncated Fourier series, the equations can be solved in a semi-closed form, leading to a better understanding of Stirling engine behavior. The theory further includes a Second Law analysis; therefore, the efficiency and power losses resulting from effects of adiabatic cylinders, transient heat transfer, pressure drop, and seal leakage can be allocated unambiguously, and the degree of loss coupling can be assessed.

  9. Short- and long-term functional plasticity of white matter induced by oligodendrocyte depolarization in the hippocampus.

    PubMed

    Yamazaki, Yoshihiko; Fujiwara, Hiroki; Kaneko, Kenya; Hozumi, Yasukazu; Xu, Ming; Ikenaka, Kazuhiro; Fujii, Satoshi; Tanaka, Kenji F

    2014-08-01

    Plastic changes in white matter have received considerable attention in relation to normal cognitive function and learning. Oligodendrocytes and myelin, which constitute the white matter in the central nervous system, can respond to neuronal activity with prolonged depolarization of membrane potential and/or an increase in the intracellular Ca(2+) concentration. Depolarization of oligodendrocytes increases the conduction velocity of an action potential along axons myelinated by the depolarized oligodendrocytes, indicating that white matter shows functional plasticity, as well as structural plasticity. However, the properties and mechanism of oligodendrocyte depolarization-induced functional plastic changes in white matter are largely unknown. Here, we investigated the functional plasticity of white matter in the hippocampus using mice with oligodendrocytes expressing channelrhodopsin-2. Using extracellular recordings of compound action potentials at the alveus of the hippocampus, we demonstrated that light-evoked depolarization of oligodendrocytes induced early- and late-onset facilitation of axonal conduction that was dependent on the magnitude of oligodendrocyte depolarization; the former lasted for approximately 10 min, whereas the latter continued for up to 3 h. Using whole-cell recordings from CA1 pyramidal cells and recordings of antidromic action potentials, we found that the early-onset short-lasting component included the synchronization of action potentials. Moreover, pharmacological analysis demonstrated that the activation of Ba(2+) -sensitive K(+) channels was involved in early- and late-onset facilitation, whereas 4-aminopyridine-sensitive K(+) channels were only involved in the early-onset component. These results demonstrate that oligodendrocyte depolarization induces short- and long-term functional plastic changes in the white matter of the hippocampus and plays active roles in brain functions. © 2014 Wiley Periodicals, Inc.

  10. Effects of climatic variables on weight loss: a global analysis

    PubMed Central

    Ustulin, Morena; Keum, Changwon; Woo, Junghoon; Woo, Jeong-taek; Rhee, Sang Youl

    2017-01-01

    Several studies have analyzed the effects of weather on factors associated with weight loss. In this study, we directly analyzed the effect of weather on intentional weight loss using global-scale data provided by smartphone applications. Through Weather Underground API and the Noom Coach application, we extracted information on weather and body weight for each user located in each of several geographic areas on all login days. We identified meteorological information (pressure, precipitation, wind speed, dew point, and temperature) and self-monitored body weight data simultaneously. A linear mixed-effects model was performed analyzing 3274 subjects. Subjects in North America had higher initial BMIs than those of subjects in Eastern Asia. During the study period, most subjects who used the smartphone application experienced weight loss in a significant way (80.39%, p-value < 0.001). Subjects who infrequently recorded information about dinner had smaller variations than those of other subjects (βfreq.users dinner*time = 0.007, p-value < 0.001). Colder temperature, lower dew point, and higher values for wind speed and precipitation were significantly associated with weight loss. In conclusion, we found a direct and independent impact of meteorological conditions on intentional weight loss efforts on a global scale (not only on a local level). PMID:28106167

  11. Seizures, refractory status epilepticus, and depolarization block as endogenous brain activities

    NASA Astrophysics Data System (ADS)

    El Houssaini, Kenza; Ivanov, Anton I.; Bernard, Christophe; Jirsa, Viktor K.

    2015-01-01

    Epilepsy, refractory status epilepticus, and depolarization block are pathological brain activities whose mechanisms are poorly understood. Using a generic mathematical model of seizure activity, we show that these activities coexist under certain conditions spanning the range of possible brain activities. We perform a detailed bifurcation analysis and predict strategies to escape from some of the pathological states. Experimental results using rodent data provide support of the model, highlighting the concept that these pathological activities belong to the endogenous repertoire of brain activities.

  12. Analysis of evaporative water loss in the Skylab astronauts

    NASA Technical Reports Server (NTRS)

    Leonard, J. I.

    1977-01-01

    Daily evaporative water losses (EWL) during the three Skylab missions were measured using the indirect mass and water balance techniques. A mean inflight EWL of 860 ml/day-m 2 was obtained for nine men who averaged one hour of daily exercise. Although it was expected the EWL would increase in the hypobaric environment of Skylab (1/3 atmosphere), an average decrease from preflight sea level conditions of 11 percent was measured. The results suggest that weightlessness may have been a factor in modifying EWL primarily by decreasing sweat losses during exercise and possibly by reducing insensible skin losses as well. The weightless environment apparently promotes the formation of a sweat film on the skin surface both directly, by reducing heat and mass convective flow and sweat drippage, and perhaps indirectly by inducing measurable biochemical changes resulting in high initial sweating rates. It is proposed that these high levels of skin wettedness favor sweat suppression by a previously described mechanism.

  13. Progress of Stirling cycle analysis and loss mechanism characterization

    NASA Technical Reports Server (NTRS)

    Tew, R. C., Jr.

    1986-01-01

    An assessment of Stirling engine thermodynamic modeling and design codes shows a general deficiency; this deficiency is due to poor understanding of the fluid flow and heat transfer phenomena that occur in the oscillating flow and pressure level environment within the engines. Stirling engine thermodynamic loss mechanisms are listed. Several experimental and computational research efforts now underway to characterize various loss mechanisms are reviewed. The need for additional experimental rigs and rig upgrades is discussed. Recent developments and current efforts in Stirling engine thermodynamic modeling are also reviewed.

  14. Progress of Stirling cycle analysis and loss mechanism characterization

    SciTech Connect

    Tew, R.C. Jr.

    1986-01-01

    An assessment of Stirling engine thermodynamic modeling and design codes shows a general deficiency; this deficiency is due to poor understanding of the fluid flow and heat transfer phenomena that occur in the oscillating flow and pressure level environment within the engines. Requirements for improving modeling and design are discussed. Stirling engine thermodynamic loss mechanisms are listed. Several experimental and computational research efforts now underway to characterize various loss mechanisms are reviewed. The need for additional experimental rigs and rig upgrades is discussed. Recent developments and current efforts in Stirling engine thermodynamic modeling are also reviewed.

  15. Depolarization ratios retrieved by AERONET sun-sky radiometer data and comparison to depolarization ratios measured with lidar

    NASA Astrophysics Data System (ADS)

    Noh, Youngmin; Müller, Detlef; Lee, Kyunghwa; Kim, Kwanchul; Lee, Kwonho; Shimizu, Atsushi; Kim, Sang-Woo; Sano, Itaru; Park, Chan Bong

    2017-05-01

    The linear particle depolarization ratios at 440, 675, 870, and 1020 nm were derived using data taken with the AERONET sun-sky radiometer at Seoul (37.45° N, 126.95° E), Kongju (36.47° N, 127.14° E), Gosan (33.29° N, 126.16° E), and Osaka (34.65° N, 135.59° E). The results are compared to the linear particle depolarization ratio measured by lidar at 532 nm. The correlation coefficient R2 between the linear particle depolarization ratio derived by AERONET data at 1020 nm and the linear particle depolarization ratio measured with lidar at 532 nm is 0.90, 0.92, 0.79, and 0.89 at Seoul, Kongju, Gosan, and Osaka, respectively. The correlation coefficients between the lidar-measured depolarization ratio at 532 nm and that retrieved by AERONET at 870 nm are 0.89, 0.92, 0.76, and 0.88 at Seoul, Kongju, Gosan, and Osaka, respectively. The correlation coefficients for the data taken at 675 nm are lower than the correlation coefficients at 870 and 1020 nm, respectively. Values are 0.81, 0.90, 0.64, and 0.81 at Seoul, Kongju, Gosan, and Osaka, respectively. The lowest correlation values are found for the AERONET-derived linear particle depolarization ratio at 440 nm, i.e., 0.38, 0.62, 0.26, and 0.28 at Seoul, Kongju, Gosan, and Osaka, respectively. We should expect a higher correlation between lidar-measured linear particle depolarization ratios at 532 nm and the ones derived from AERONET at 675 and 440 nm as the lidar wavelength is between the two AERONET wavelengths. We cannot currently explain why we find better correlation between lidar and AERONET linear particle depolarization ratios for the case that the AERONET wavelengths (675, 870, and 1020 nm) are significantly larger than the lidar measurement wavelength (532 nm). The linear particle depolarization ratio can be used as a parameter to obtain insight into the variation of optical and microphysical properties of dust when it is mixed with anthropogenic pollution particles. The single-scattering albedo

  16. Spectral analysis of hearing protector impulsive insertion loss.

    PubMed

    Fackler, Cameron J; Berger, Elliott H; Murphy, William J; Stergar, Michael E

    2017-01-01

    To characterise the performance of hearing protection devices (HPDs) in impulsive-noise conditions and to compare various protection metrics between impulsive and steady-state noise sources with different characteristics. HPDs were measured per the impulsive test methods of ANSI/ASA S12.42- 2010 . Protectors were measured with impulses generated by both an acoustic shock tube and an AR-15 rifle. The measured data were analysed for impulse peak insertion loss (IPIL) and impulsive spectral insertion loss (ISIL). These impulsive measurements were compared to insertion loss measured with steady-state noise and with real-ear attenuation at threshold (REAT). Tested HPDs included a foam earplug, a level-dependent earplug and an electronic sound-restoration earmuff. IPIL for a given protector varied between measurements with the two impulse noise sources, but ISIL agreed between the two sources. The level-dependent earplug demonstrated level-dependent effects both in IPIL and ISIL. Steady-state insertion loss and REAT measurements tended to provide a conservative estimate of the impulsively-measured attenuation. Measurements of IPIL depend strongly on the source used to measure them, especially for HPDs with less attenuation at low frequencies. ISIL provides an alternative measurement of impulse protection and appears to be a more complete description of an HPD's performance.

  17. Spectral analysis of hearing protector impulsive insertion loss

    PubMed Central

    Fackler, Cameron J.; Berger, Elliott H.; Murphy, William J.; Stergar, Michael E.

    2017-01-01

    Objective To characterize the performance of hearing protection devices in impulsive-noise conditions and to compare various protection metrics between impulsive and steady-state noise sources with different characteristics. Design Hearing protectors were measured per the impulsive test methods of ANSI/ASA S12.42-2010. Protectors were measured with impulses generated by both an acoustic shock tube and an AR-15 rifle. The measured data were analyzed for impulse peak insertion loss (IPIL) and impulsive spectral insertion loss (ISIL). These impulsive measurements were compared to insertion loss measured with steady-state noise and with real-ear attenuation at threshold (REAT). Study Sample Tested devices included a foam earplug, a level-dependent earplug, and an electronic sound-restoration earmuff. Results IPIL for a given protector varied between measurements with the two impulse noise sources, but ISIL agreed between the two sources. The level-dependent earplug demonstrated level-dependent effects both in IPIL and ISIL. Steady-state insertion loss and REAT measurements tended to provide a conservative estimate of the impulsively-measured attenuation. Conclusions Measurements of IPIL depend strongly on the source used to measure them, especially for hearing protectors with less attenuation at low frequencies. ISIL provides an alternative measurement of impulse protection and appears to be a more complete description of an HPD’s performance. PMID:27885881

  18. Psychophysical Analysis of Foveal Visual Losses in Glaucoma.

    NASA Astrophysics Data System (ADS)

    Pierce, Gilbert Eugene

    It has been suggested that glaucoma selectively damages large retinal ganglion cells. Quigley and others have shown anatomically that the larger retinal ganglion cells (M-cells) are destroyed, while the smaller retinal ganglion cells (P-cells) are relatively spared. However, others have shown, especially by measurements of color vision and color visual fields, that P-cells may also be damaged, often to a greater extent than M-cells. This study was done in an effort to determine which retinal ganglion cells are affected in glaucoma. Twenty-four glaucoma patients were tested using the color-mixture threshold technique of King-Smith. Spatial and temporal contrast sensitivity functions were also performed on each patient. It was found that red-green color vision losses were more common than achromatic visual losses (17 eyes vs. 8 eyes), suggesting that small cell losses may lead large cell losses. Correlation analyses showed that in general, eyes which had a large amount of damage to M-cells also had a large amount of damage to P-cells. We conclude that, at the fovea, P-cell damage in early glaucoma is at least as common as M-cell damage. It is hypothesized that while M-cells may be more readily destroyed than P-cells, the functional properties of P -cells at the fovea are diminished in glaucoma, possibly without their destruction.

  19. Effect of multiple scattering on depolarization measurements with spaceborne lidars.

    PubMed

    Reichardt, Susanne; Reichardt, Jens

    2003-06-20

    An analytical model based on the integration of the scattering-angle and light-path manifold has been developed to quantify the effect of multiple scattering on cirrus measurements obtained with elastic polarization lidars from space. Light scattering by molecules and by a horizontally homogeneous cloud is taken into account. Lidar parameter, including laser beam divergence, can be freely chosen. Up to 3 orders of scattering are calculated. Furthermore, an inversion technique for the retrieval of cloud extinction profiles from measurements with elastic-backscatter lidars is proposed that explicitly takes multiple scattering into account. It is found that for typical lidar system parameters such as those of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) instrument multiple scattering does not significantly affect depolarization-ratio measurements in cirrus clouds with small to moderate optical depths. For all simulated clouds, the absolute value of the difference between measured and single-scattering volume depolarization ratio is < 0.006. The particle depolarization ratio can be calculated from the measured volume depolarization ratio and the retrieved backscatter ratio without degradation of accuracy; thus characterization of the various cirrus categories in terms of the particle depolarization ratio and retrieval of cloud microphysical properties is feasible from space. The results of this study apply to polar stratospheric clouds as well.

  20. Hysteresis Loss Analysis of Soft Magnetic Materials Under Direct Current Bias Conditions (Preprint)

    DTIC Science & Technology

    2015-09-01

    correlated higher losses is not well understood. A domain imaging study under applied fields that uses the conditions reported in this study may...AFRL-RQ-WP-TP-2015-0133 Hysteresis Loss Analysis of Soft Magnetic Materials Under Direct Current Bias Conditions (Preprint) Zafer Turgut...Technical Paper 1 October 2013 to 1 September 2015 4. TITLE AND SUBTITLE Hysteresis Loss Analysis of Soft Magnetic Materials Under Direct Current Bias

  1. Evidence for the 2B1-2A1 electronic transition in chlorine dioxide from resonance Raman depolarization ratios

    NASA Astrophysics Data System (ADS)

    Reid, Philip J.; Esposito, Anthony P.; Foster, Catherine E.; Beckman, Robert A.

    1997-11-01

    The resonance Raman depolarization ratios of chlorine dioxide (OClO) dissolved in cyclohexane are measured and analyzed to establish the existence of a 2A1 excited state that is nearly degenerate with the optically stronger, 2A2 excited state. The depolarization ratio of the symmetric stretch fundamental transition is measured at several excitation wavelengths spanning the lowest-energy electronic transition centered at ˜360 nm. The depolarization ratio of this transition reaches a maximum value of 0.25±0.04 directly on resonance suggesting that scattered intensity is not derived from a single excited state. The depolarization ratios are modeled utilizing the time-dependent formalism for Raman scattering. This analysis demonstrates that the observed Raman depolarization ratios are derived from contributions of two excited states of 2A1 and 2A2 symmetry to the observed scattering. The results presented here support the emerging picture of OClO excited-state reaction dynamics in which photoexcitation to the 2A2 excited state is followed by internal conversion from this state to the 2A1 surface. Both the role of the 2A1 state in the photochemistry of OClO and the importance of this state in modeling resonance Raman intensities are discussed.

  2. Isothermal depolarization current in metal-oxide varistor ceramics under various polarizing fields

    NASA Astrophysics Data System (ADS)

    Tonkoshkur, Yu. A.; Lyashkov, A. Yu.; Tonkoshkur, A. S.

    2013-08-01

    A method of analysis of experimental kinetic dependences of isothermal depolarization currents in metal-oxide varistor ceramics composed of ZnO-Bi2O3-CoO-Sb2O3-SnO2-MnO-B2O3 has been proposed and tested. The method is based on reconstruction of dependences with the use of the Kohlrausch-Williams-Watt function. Expansion of the distribution and reduction of the average time of dielectric relaxation of the depolarization were found as the magnitude of the polarizing electric field increased. These findings have been interpreted in the framework of the notion of participation in the recharge of localized states more distant from the Fermi level in the crystallites of zinc-oxide ceramics under increased polarizing fields.

  3. Depolarization of D-T plasmas by recycling in material walls

    SciTech Connect

    Greenside, H.S.; Budny, R.V.; Post, D.E.

    1984-02-01

    The feasibility of using polarized deuterium (D) and tritium (T) plasmas in fusion reactors may be seriously affected by recycling in material walls. Theoretical and experimental results are reviewed which show how the depolarization rates of absorbed D and T depend on first wall parameters such as the temperature, the bulk and surface diffusivities, the density of electronic states at the Fermi surface, the spectral density of microscopic fluctuating electric field gradients, and the concentration of paramagnetic impurities. Nuclear magnetic resonance (NMR) spectroscopy of hydrogenated and deuterated amorphous semiconductors suggests that low-Z nonmetallic materials may provide a satisfactory first wall or limiter coating under reactor conditions with characteristic depolarization times of several seconds. Experiments are proposed to test the consequences of our analysis.

  4. Analysis of losses in supersonic mixing and reacting flows

    NASA Astrophysics Data System (ADS)

    Riggins, D. W.; McClinton, C. R.

    1991-06-01

    A method for analyzing flow losses and thrust potential in supersonic combustors is presented. This method relies on a complete and consistent one-dimensional representation of a three-dimensional flow-field. Numerical results for flush wall fuel injection into a Mach 3 flow are examined and comparisons are made with experimental measurements of fuel concentration. Mixing results for a swept injection ramp, a straight (unswept) injection ramp, and a thirty degree downstream-directed flush wall jet in the same combustor duct are analyzed. The flow loss/thrust potential of the flush wall jet and the swept ramp are investigated (based on reacting solutions) using computed combustor effectiveness. The wall jet displays slightly higher thrust potential than the swept ramp at the end of the combustor.

  5. Depolarization and attenuation effects of radomes at 20 GHz

    NASA Astrophysics Data System (ADS)

    Hendrix, Charles E.; McNally, James E.; Monzingo, Robert A.

    1989-03-01

    The problem of describing the attenuation and depolarization effects of a wet radome on a transmitted signal is considered by experiments carried out with two commonly used radome materials, ESSCOLAM-6 and ESSCOLAM-8. The results suggest that a two-component model of depolarization is required to account for the observed results. Predictions for the behavior of a complete radome are obtained, but full-scale testing with an operating radome to compare predicted and actual results remains to be done. An important conclusion is that, while highly water-repellent radome materials are desirable from the point of view of attenuation, they are not so desirable in terms of the degree of depolarization introduced between orthogonally polarized signal components in frequency-reuse systems.

  6. Susceptibility of Primary Sensory Cortex to Spreading Depolarizations

    PubMed Central

    Bogdanov, Volodymyr B.; Middleton, Natalie A.; Theriot, Jeremy J.; Parker, Patrick D.; Abdullah, Osama M.; Ju, Y. Sungtaek; Hartings, Jed A.

    2016-01-01

    Spreading depolarizations (SDs) are recognized as actors in neurological disorders as diverse as migraine and traumatic brain injury (TBI). Migraine aura involves sensory percepts, suggesting that sensory cortices might be intrinsically susceptible to SDs. We used optical imaging, MRI, and field potential and potassium electrode recordings in mice and electrocorticographic recordings in humans to determine the susceptibility of different brain regions to SDs. Optical imaging experiments in mice under isoflurane anesthesia showed that both cortical spreading depression and terminal anoxic depolarization arose preferentially in the whisker barrel region of parietal sensory cortex. MRI recordings under isoflurane, ketamine/xylazine, ketamine/isoflurane, and urethane anesthesia demonstrated that the depolarizations did not propagate from a subcortical source. Potassium concentrations showed larger increases in sensory cortex, suggesting a mechanism of susceptibility. Sensory stimulation biased the timing but not the location of depolarization onset. In humans with TBI, there was a trend toward increased incidence of SDs in parietal/temporal sensory cortex compared with other regions. In conclusion, SDs are inducible preferentially in primary sensory cortex in mice and most likely in humans. This tropism can explain the predominant sensory phenomenology of migraine aura. It also demonstrates that sensory cortices are vulnerable in brain injury. SIGNIFICANCE STATEMENT Spreading depolarizations (SDs) are involved in neurologic disorders as diverse as migraine and traumatic brain injury. In migraine, the nature of aura symptoms suggests that sensory cortex may be preferentially susceptible. In brain injury, SDs occur at a vulnerable time, during which the issue of sensory stimulation is much debated. We show, in mouse and human, that sensory cortex is more susceptible to SDs. We find that sensory stimulation biases the timing but not the location of the depolarizations

  7. Prokineticin 2 depolarizes paraventricular nucleus magnocellular and parvocellular neurons.

    PubMed

    Yuill, Erik A; Hoyda, Ted D; Ferri, Catharine C; Zhou, Qun-Yong; Ferguson, Alastair V

    2007-01-01

    Blind whole-cell patch-clamp techniques were used to examine the effects of prokineticin 2 (PK2) on the excitability of magnocellular (MNC), parvocellular preautonomic (PA), and parvocellular neuroendocrine (NE) neurons within the hypothalamic paraventricular nucleus (PVN) of the rat. The majority of MNC neurons (76%) depolarized in response to 10 nm PK2, effects that were eliminated in the presence of tetrodotoxin (TTX). PK2 also caused an increase in excitatory postsynaptic potential (EPSP) frequency, a finding that was confirmed by voltage clamp recordings demonstrating increases in excitatory postsynaptic current (EPSC) frequency. The depolarizing effects of PK2 on MNC neurons were also abolished by kynurenic acid (KA), supporting the conclusion that the effects of PK2 are mediated by the activation of glutamate interneurons within the hypothalamic slice. PA (68%) and NE (67%) parvocellular neurons also depolarized in response to 10 nm PK2. However, in contrast to MNC neurons, these effects were maintained in TTX, indicating that PK2 directly affects PA and NE neurons. PK2-induced depolarizations observed in PA and NE neurons were found to be concentration-related and receptor mediated, as experiments performed in the presence of A1MPK1 (a PK2 receptor antagonist) abolished the effects of PK2 on these subpopulations of neurons. The depolarizing effects of PK2 on PA and NE neurons were also shown to be abolished by PD 98059 (a mitogen activated protein kinase (MAPK) inhibitor) suggesting that PK2 depolarizes PVN parvocellular neurons through a MAPK signalling mechanism. In combination, these studies have identified separate cellular mechanisms through which PK2 influences the excitability of different subpopulations of PVN neurons.

  8. Spin Depolarization due to Beam-Beam Interaction in Nlc

    NASA Astrophysics Data System (ADS)

    Thompson, Kathleen A.

    2002-04-01

    Calculations of spin depolarization effects due to the beam-beam interaction are presented for several NLC designs. The depolarization comes from both classical (Bargmann-Michel-Telegdi precession) and quantum (Sokolov-Ternov spin-flip) effects. It is anticipated that some physics experiments at future colliders will require a knowledge of the polarization to better than 0.5% precision. We compare the results of CAIN simulations with the analytic estimates of Yokoya and Chen for head-on collisions.1 We also study the effects of transverse offsets and beamstrahlung-induced energy spread.

  9. Nonspherical nanoparticles characterization by partially depolarized dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Levin, Alexander D.; Shmytkova, Ekaterina A.

    2015-06-01

    The realization of improved depolarized dynamic light scattering method is presented. This technique supports measurement of non-spherical nanoparticals dimensions in liquids. The relations between translational and rotational diffusion coefficients and autocorrelation function of scattered light with polarized and depolarized components in various proportions are derived. Thus measurement of very weak cross-polarized component can be avoided. This improvement permits to reduce measurement time, to improve signal to noise ratio and results precision. The technique was applied for sizing of gold nanorods and multiwalled carbon nanotubes in liquids.

  10. Dark-field circular depolarization optical coherence microscopy

    PubMed Central

    Mehta, Kalpesh; Zhang, Pengfei; Yeo, Eugenia Li Ling; Kah, James Chen Yong; Chen, Nanguang

    2013-01-01

    Optical coherence microscopy (OCM) is a widely used structural imaging modality. To extend its application in molecular imaging, gold nanorods are widely used as contrast agents for OCM. However, they very often offer limited sensitivity as a result of poor signal to background ratio. Here we experimentally demonstrate that a novel OCM implementation based on dark-field circular depolarization detection can efficiently detect circularly depolarized signal from gold nanorods and at the same time efficiently suppress the background signals. This results into a significant improvement in signal to background ratio. PMID:24049689

  11. Observation of wide rf induced synchrotron sideband depolarizing resonances.

    NASA Astrophysics Data System (ADS)

    Bychkov, M. A.; Anferov, V. A.; Blinov, B. B.; Courant, E. D.; Crandell, D. A.; Derbenev, Ya. S.; Kaufman, W. A.; Krisch, A. D.; Lorenzon, W.; Nurushev, T. S.; Phelps, R. A.; Wong, V. K.; Caussyn, D. D.; Chu, C. M.; Ellison, T. J. P.; Lee, S. Y.; Rinckel, T.; Schwandt, P.; Sperisen, F.; Stephenson, E. J.; von Przewoski, B.; Ohmori, C.; Minty, M. G.; Russell, A. D.

    1997-04-01

    In a recent experiment with a stored 104.1 MeV vertically polarized proton beam at the IUCF Cooler Ring, we depolarized the beam using an rf solenoid with a magnetic field of about 1.3\\cdot10-3T\\cdotm. We observed the two expected rf depolarizing resonances centered around the protons' 1.5 MHz circulation frequency as in previous experiments. Near each of these resonances, we also found synchrotron sidebands which are caused by the proton's energy oscillations. The strengths and widths of the synchrotron resonances were quite different for the sidebands above and below the circulation frequency.

  12. Vanadate induces necrotic death in neonatal rat cardiomyocytes through mitochondrial membrane depolarization.

    PubMed

    Soares, Sandra Sofia; Henao, Fernando; Aureliano, Manuel; Gutiérrez-Merino, Carlos

    2008-03-01

    Besides the well-known inotropic effects of vanadium in cardiac muscle, previous studies have shown that vanadate can stimulate cell growth or induce cell death. In this work, we studied the toxicity to neonatal rat ventricular myocytes (cardiomyocytes) of two vanadate solutions containing different oligovanadates distribution, decavanadate (containing decameric vanadate, V 10) and metavanadate (containing monomeric vanadate and also di-, tetra-, and pentavanadate). Incubation for 24 h with decavanadate or metavanadate induced necrotic cell death of cardiomyocytes, without significant caspase-3 activation. Only 10 microM total vanadium of either decavanadate (1 microM V 10) or metavanadate (10 microM total vanadium) was needed to produce 50% loss of cell viability after 24 h (assessed with MTT and propidium iodide assays). Atomic absorption spectroscopy showed that vanadium accumulation in cardiomyocytes after 24 h was the same when incubation was done with decavanadate or metavanadate. A decrease of 75% of the rate of mitochondrial superoxide anion generation, monitored with dihydroethidium, and a sustained rise of cytosolic calcium (monitored with Fura-2-loaded cardiomyocytes) was observed after 24 h of incubation of cardiomyocytes with decavanadate or metavanadate concentrations close to those inducing 50% loss of cell viability produced. In addition, mitochondrial membrane depolarization within cardiomyocytes, monitored with tetramethylrhodamine ethyl esther or with 3,3',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide, were observed after only 6 h of incubation with decavanadate or metavanadate. The concentration needed for 50% mitochondrial depolarization was 6.5 +/- 1 microM total vanadium for both decavanadate (0.65 microM V 10) and metavanadate. In conclusion, mitochondrial membrane depolarization was an early event in decavanadate- and monovanadate-induced necrotic cell death of cardiomyocytes.

  13. The influence of rotational depolarization on the mechanism of energy transport in two-component systems: The nature of correlations.

    PubMed

    Bojarski, P; Kawski, A

    1993-06-01

    The correlation effect in two-component systems of different viscosities was analyzed based on a concentration depolarization experiment. The inclusion of a correlation effect was found to be fully justified only in systems for which the localization time, τl, is considerably shorter than that of the rotational relaxation, τrot. On the grounds of an approximate analysis, taking into account the competition between the concentration and the rotational depolarization, it was possible to explain the concentration changes in the emission anisotropy in the systems investigated.

  14. Analysis of axially non-uniform loss distribution in 3-phase induction motor considering skew effect

    SciTech Connect

    Kown, B.I.; Kim, B.T.; Jun, C.S.; Park, S.C. )

    1999-05-01

    This paper discusses the phenomena of the axially non-uniform distribution of magnetic flux densities and losses in a 3-phase squirrel cage induction motor of which the rotor bars are skewed. A 2-dimensional complex finite element method taking account of the effects of the skewed rotor bars is utilized for the analysis of characteristics such as copper and iron losses and the loss distributions are examined. The summing up values of non-uniform losses resulted from the finite element analysis are compared with measurement values.

  15. Emergency cooling analysis for the loss of coolant malfunction

    NASA Technical Reports Server (NTRS)

    Peoples, J. A.

    1972-01-01

    This report examines the dynamic response of a conceptual space power fast-spectrum lithium cooled reactor to the loss of coolant malfunction and several emergency cooling concepts. The results show that, following the loss of primary coolant, the peak temperatures of the center most 73 fuel elements can range from 2556 K to the region of the fuel melting point of 3122 K within 3600 seconds after the start of the accident. Two types of emergency aftercooling concepts were examined: (1) full core open loop cooling and (2) partial core closed loop cooling. The full core open loop concept is a one pass method of supplying lithium to the 247 fuel pins. This method can maintain fuel temperature below the 1611 K transient damage limit but requires a sizable 22,680-kilogram auxiliary lithium supply. The second concept utilizes a redundant internal closed loop to supply lithium to only the central area of each hexagonal fuel array. By using this method and supplying lithium to only the triflute region, fuel temperatures can be held well below the transient damage limit.

  16. Surfactant modulates calcium response of neutrophils to physiologic stimulation via cell membrane depolarization.

    PubMed

    Chacon-Cruz, E; Buescher, E S; Oelberg, D G

    2000-03-01

    Pulmonary surfactant (PS) reduces inflammation in the lung by poorly understood mechanisms. We have observed that surfactant-associated proteins (SAP) insert monovalent cation channels in artificial membranes. Neutrophils are primary mediators of acute pulmonary inflammation, and their functions are activated by increases in cytosolic ionized calcium concentration ([Ca2+]) and by changes in membrane potential. We hypothesize that PS inserts SAP-dependent cation channels in neutrophils, causing membrane depolarization, altered [Ca2+] response, and depressed activation. Human neutrophils were isolated, exposed to PS+SAP (1% Survanta), PS-SAP (1% Exosurf), or buffer, and washed before activating with selected stimulants. PS+SAP reduced phorbol ester- and formyl peptide-stimulated adherence and aggregation by 38% (p < 0.05) and 54% (p < 0.02), respectively. PS+SAP also inhibited the formyl peptide-induced [Ca2+] response of neutrophils (p < 0.01), but only in the presence of external Ca2+. Further characterization of this inhibition demonstrated that PS+SAP blocked formyl peptide-induced influx of both Ca2+ and Mn2+, and that this inhibition was present during activation by other neutrophil stimulants (IL-8, immune complexes). Prior depolarization of neutrophils with gramicidin-D similarly inhibited the [Ca2+] response of neutrophils to formyl peptide, and analysis of neutrophil membrane potential by 3,3'-dipentyloxaearbocyanine iodide (diOC5(3)) fluorescence revealed that PS+SAP induced rapid neutrophil depolarization. In contrast, PS-SAP exhibited little effect on neutrophil function, [Ca2+], or membrane potential. We conclude that PS+SAP decreases neutrophil adherence and aggregation responses, blocks Ca2+ influx after physiologic stimulation, and decreases membrane potential. We speculate that these effects are caused by membrane depolarization via SAP-dependent cation channel insertion, and that all of these effects contribute to the antiinflammatory properties of

  17. Fluorescence/depolarization lidar for mid-range stand-off detection of biological agents

    NASA Astrophysics Data System (ADS)

    Mierczyk, Z.; Kopczyński, K.; Zygmunt, M.; Wojtanowski, J.; Młynczak, J.; Gawlikowski, A.; Młodzianko, A.; Piotrowski, W.; Gietka, A.; Knysak, P.; Drozd, T.; Muzal, M.; Kaszczuk, M.; Ostrowski, R.; Jakubaszek, M.

    2011-06-01

    LIDAR system for real-time standoff detection of bio-agents is presented and preliminary experimental results are discussed. The detection approach is based on two independent physical phenomena: (1) laser induced fluorescence (LIF), (2) depolarization resulting from elastic scattering on non-spherical particles. The device includes three laser sources, two receiving telescopes, depolarization component and spectral signature analyzing spectrograph. It was designed to provide the stand-off detection capability at ranges from 200 m up to several kilometers. The system as a whole forms a mobile platform for vehicle or building installation. Additionally, it's combined with a scanning mechanics and advanced software, which enable to conduct the semi-automatic monitoring of a specified space sector. For fluorescence excitation, 3-rd (355 nm) and 4-th (266 nm) harmonics of Nd:YAG pulsed lasers are used. They emit short (~6 ns) pulses with the repetition rate of 20 Hz. Collecting optics for fluorescence echo detection and spectral content analysis includes 25 mm diameter f/4 Newton telescope, Czerny Turner spectrograph and 32-channel PMT. Depending on the grating applied, the spectral resolution from 20 nm up to 3 nm per channel can be achieved. The system is also equipped with an eye-safe (1.5 μm) Nd:YAG OPO laser for elastic backscattering/depolarization detection. The optical echo signal is collected by Cassegrain telescope with aperture diameter of 12.5 mm. Depolarization detection component based on polarizing beam-splitter serves as the stand-off particle-shape analyzer, which is very valuable in case of non-spherical bio-aerosols sensing.

  18. Boreal tree pollen sensed by polarization lidar: Depolarizing biogenic chaff

    NASA Astrophysics Data System (ADS)

    Sassen, Kenneth

    2008-09-01

    Polarization (0.694 μm) lidar measurements show that tree pollen can generate strong laser depolarization in the backscatter from the lower atmosphere. Examples are given illustrating that linear depolarization ratios up to 0.3 are measured in plumes of paper birch pollen at the onset of boreal forest green-out. These pollen are ~25 μm in diameter and near-spherical in shape, but with lobes protruding from a surface membrane, which appears to produce the depolarization. Similar lidar findings are frequently observed during the summer at Fairbanks, Alaska, indicating that various types of seasonal pollen releases may be identified by polarization lidar. This scattering behavior is likely a general attribute of pollen and other suspended biogenic debris, which has implications for benefiting human health. This source of laser depolarization should not be confused with the presence of airborne dust or certain pollution particles, but is a natural background aerosol component caused by plant reproduction, as should be recognized in current global polarization lidar aerosol research using the CALIPSO satellite.

  19. Primary afferent depolarization evoked by a painful stimulus.

    PubMed

    Vyklický, L; Rudomin, P; Zajac, F E; Burke, R E

    1969-07-11

    Pulses of intense radiant heat applied to the plantar pad of unanesthetized spinal cats produced negative dorsal root potentials, increased excitability of cutaneous A fibers, and marked activation of ipsilateral flexor motoneurons. The same effects were obtained during cold block of A fiber conduction in the appropriate peripheral nerve. We conclude that adequate noxious activation of cutaneous C fibers depolarizes cutaneous A fibers.

  20. Decavanadate induces mitochondrial membrane depolarization and inhibits oxygen consumption.

    PubMed

    Soares, S S; Gutiérrez-Merino, C; Aureliano, M

    2007-05-01

    Decavanadate induced rat liver mitochondrial depolarization at very low concentrations, half-depolarization with 39 nM decavanadate, while it was needed a 130-fold higher concentration of monomeric vanadate (5 microM) to induce the same effect. Decavanadate also inhibits mitochondrial repolarization induced by reduced glutathione in vitro, with an inhibition constant of 1 microM, whereas no effect was observed up to 100 microM of monomeric vanadate. The oxygen consumption by mitochondria is also inhibited by lower decavanadate than monomeric vanadate concentrations, i.e. 50% inhibition is attained with 99 M decavanadate and 10 microM monomeric vanadate. Thus, decavanadate is stronger as mitochondrial depolarization agent than as inhibitor of mitochondrial oxygen consumption. Up to 5 microM, decavanadate does not alter mitochondrial NADH levels nor inhibit neither F(O)F(1)-ATPase nor cytochrome c oxidase activity, but it induces changes in the redox steady-state of mitochondrial b-type cytochromes (complex III). NMR spectra showed that decameric vanadate is the predominant vanadate species in decavanadate solutions. It is concluded that decavanadate is much more potent mitochondrial depolarization agent and a more potent inhibitor of mitochondrial oxygen consumption than monomeric vanadate, pointing out the importance to take into account the contribution of higher oligomeric species of vanadium for the biological effects of vanadate solutions.

  1. Migraine prophylaxis, ischemic depolarizations and stroke outcomes in mice

    PubMed Central

    Eikermann-Haerter, Katharina; Lee, Jeong Hyun; Yalcin, Nilufer; Yu, Esther Sori; Daneshmand, Ali; Wei, Ying; Zheng, Yi; Can, Anil; Sengul, Buse; Ferrari, Michel D.; van den Maagdenberg, Arn M. J. M.; Ayata, Cenk

    2014-01-01

    Background and Purpose Migraine with aura is an established stroke risk factor, and excitatory mechanisms such as spreading depression are implicated in the pathogenesis of both migraine and stroke. Spontaneous spreading depression waves originate within the peri-infarct tissue and exacerbate the metabolic mismatch during focal cerebral ischemia. Genetically enhanced spreading depression susceptibility facilitates anoxic depolarizations and peri-infarct spreading depressions and accelerates infarct growth, suggesting that susceptibility to spreading depression is a critical determinant of vulnerability to ischemic injury. Because chronic treatment with migraine prophylactic drugs suppresses spreading depression susceptibility, we tested whether migraine prophylaxis can also suppress ischemic depolarizations and improve stroke outcome. Methods We measured the cortical susceptibility to spreading depression and ischemic depolarizations, and determined tissue and neurological outcome after middle cerebral artery occlusion in wild type and familial hemiplegic migraine type 1 knock-in mice treated with vehicle, topiramate or lamotrigine daily for 7 weeks or as a single dose shortly before testing. Results Chronic treatment with topiramate or lamotrigine reduces the susceptibility to KCl- or electrical stimulation-induced spreading depressions as well as ischemic depolarizations in both wild-type and familial hemiplegic migraine type 1 mutant mice. Consequently, both tissue and neurological outcomes are improved. Notably, treatment with a single dose of either drug is ineffective. Conclusions These data underscore the importance of hyperexcitability as a mechanism for increased stroke risk in migraineurs, and suggest that migraine prophylaxis may not only prevent migraine attacks but also protect migraineurs against ischemic injury. PMID:25424478

  2. Migraine prophylaxis, ischemic depolarizations, and stroke outcomes in mice.

    PubMed

    Eikermann-Haerter, Katharina; Lee, Jeong Hyun; Yalcin, Nilufer; Yu, Esther S; Daneshmand, Ali; Wei, Ying; Zheng, Yi; Can, Anil; Sengul, Buse; Ferrari, Michel D; van den Maagdenberg, Arn M J M; Ayata, Cenk

    2015-01-01

    Migraine with aura is an established stroke risk factor, and excitatory mechanisms such as spreading depression (SD) are implicated in the pathogenesis of both migraine and stroke. Spontaneous SD waves originate within the peri-infarct tissue and exacerbate the metabolic mismatch during focal cerebral ischemia. Genetically enhanced SD susceptibility facilitates anoxic depolarizations and peri-infarct SDs and accelerates infarct growth, suggesting that susceptibility to SD is a critical determinant of vulnerability to ischemic injury. Because chronic treatment with migraine prophylactic drugs suppresses SD susceptibility, we tested whether migraine prophylaxis can also suppress ischemic depolarizations and improve stroke outcome. We measured the cortical susceptibility to SD and ischemic depolarizations, and determined tissue and neurological outcomes after middle cerebral artery occlusion in wild-type and familial hemiplegic migraine type 1 knock-in mice treated with vehicle, topiramate or lamotrigine daily for 7 weeks or as a single dose shortly before testing. Chronic treatment with topiramate or lamotrigine reduced the susceptibility to KCl-induced or electric stimulation-induced SDs as well as ischemic depolarizations in both wild-type and familial hemiplegic migraine type 1 mutant mice. Consequently, both tissue and neurological outcomes were improved. Notably, treatment with a single dose of either drug was ineffective. These data underscore the importance of hyperexcitability as a mechanism for increased stroke risk in migraineurs, and suggest that migraine prophylaxis may not only prevent migraine attacks but also protect migraineurs against ischemic injury. © 2014 American Heart Association, Inc.

  3. Impossible Dreams, Impossible Choices, and Thoughts about Depolarizing the Debate

    ERIC Educational Resources Information Center

    Morrow, Susan L.; Beckstead, A. Lee; Hayes, Jeffrey A.; Haldeman, Douglas C.

    2004-01-01

    The titles of the reactions to this major contribution alone set the stage for further exploration of the issues regarding the hopes and dreams of same-sex attracted (SSA) clients in religious conflict and their therapists, issues of choice, and whether or not it is possible - or even appropriate - to depolarize the current debate (Gonsiorek,…

  4. Kinetic movement analysis in adults with vision loss.

    PubMed

    Ray, Christopher; Horvat, Michael; Williams, Michael; Blasch, Bruce

    2007-07-01

    The purpose of this investigation was to assess movement capabilities of adults with visual impairments in comparison to sighted peers. Thirty participants (n = 15 visually impaired; n = 15 without vision loss) were age and gender matched and assessed on three functional movement measures. A Walk Across, Forward Lunge, and Sit to Stand were completed on a long force plate and analyzed using Group MANOVAs. Individuals with visual impairment were more cautious and conservative in their movement as evident by significantly reduced performance on both the Walk Across assessment and the Forward Lunge task. Performance between groups was similar on the Sit to Stand maneuver. It was concluded that individuals with visual impairments are more cautious and have more difficulty performing tasks when their center of gravity is outside of their base of support.

  5. Lidar ratio and depolarization ratio for cirrus clouds.

    PubMed

    Chen, Wei-Nai; Chiang, Chih-Wei; Nee, Jan-Bai

    2002-10-20

    We report on studies of the lidar and the depolarization ratios for cirrus clouds. The optical depth and effective lidar ratio are derived from the transmission of clouds, which is determined by comparing the backscattering signals at the cloud base and cloud top. The lidar signals were fitted to a background atmospheric density profile outside the cloud region to warrant the linear response of the return signals with the scattering media. An average lidar ratio, 29 +/- 12 sr, has been found for all clouds measured in 1999 and 2000. The height and temperature dependences ofthe lidar ratio, the optical depth, and the depolarization ratio were investigated and compared with results of LITE and PROBE. Cirrus clouds detected near the tropopause are usually optically thin and mostly subvisual. Clouds with the largest optical depths were found near 12 km with a temperature of approximately -55 degrees C. The multiple-scattering effect is considered for clouds with high optical depths, and this effect lowers the lidar ratios compared with a single-scattering condition. Lidar ratios are in the 20-40 range for clouds at heights of 12.5-15 km and are smaller than approximately 30 in height above 15 km. Clouds are usually optically thin for temperatures below approximately -65 degrees C, and in this region the optical depth tends to decrease with height. The depolarization ratio is found to increase with a height at 11-15 km and smaller than 0.3 above 16 km. The variation in the depolarization ratio with the lidar ratio was also reported. The lidar and depolarization ratios were discussed in terms of the types of hexagonal ice crystals.

  6. Temporal Coding at the Immature Depolarizing GABAergic Synapse

    PubMed Central

    Valeeva, Guzel; Abdullin, Azat; Tyzio, Roman; Skorinkin, Andrei; Nikolski, Evgeny; Ben-Ari, Yehezkiel; Khazipov, Rustem

    2010-01-01

    In the developing hippocampus, GABA exerts depolarizing and excitatory actions and contributes to the generation of neuronal network driven giant depolarizing potentials (GDPs). Here, we studied spike time coding at immature GABAergic synapses and its impact on synchronization of the neuronal network during GDPs in the neonatal (postnatal days P2–6) rat hippocampal slices. Using extracellular recordings, we found that the delays of action potentials (APs) evoked by synaptic activation of GABA(A) receptors are long (mean, 65 ms) and variable (within a time window of 10–200 ms). During patch-clamp recordings, depolarizing GABAergic responses were mainly subthreshold and their amplification by persistent sodium conductance was required to trigger APs. AP delays at GABAergic synapses shortened and their variability reduced with an increase in intracellular chloride concentration during whole-cell recordings. Negative shift of the GABA reversal potential (EGABA) with low concentrations of bumetanide, or potentiation of GABA(A) receptors with diazepam reduced GDPs amplitude, desynchronized neuronal firing during GDPs and slowed down GDPs propagation. Partial blockade of GABA(A) receptors with bicuculline increased neuronal synchronization and accelerated GDPs propagation. We propose that spike timing at depolarizing GABA synapses is determined by intracellular chloride concentration. At physiological levels of intracellular chloride GABAergic depolarization does not reach the action potential threshold and amplification of GABAergic responses by non-inactivating sodium conductance is required for postsynaptic AP initiation. Slow and variable excitation at GABAergic synapse determines the level of neuronal synchrony and the rate of GDPs propagation in the developing hippocampus. PMID:20725525

  7. Temporal coding at the immature depolarizing GABAergic synapse.

    PubMed

    Valeeva, Guzel; Abdullin, Azat; Tyzio, Roman; Skorinkin, Andrei; Nikolski, Evgeny; Ben-Ari, Yehezkiel; Khazipov, Rustem

    2010-01-01

    In the developing hippocampus, GABA exerts depolarizing and excitatory actions and contributes to the generation of neuronal network driven giant depolarizing potentials (GDPs). Here, we studied spike time coding at immature GABAergic synapses and its impact on synchronization of the neuronal network during GDPs in the neonatal (postnatal days P2-6) rat hippocampal slices. Using extracellular recordings, we found that the delays of action potentials (APs) evoked by synaptic activation of GABA(A) receptors are long (mean, 65 ms) and variable (within a time window of 10-200 ms). During patch-clamp recordings, depolarizing GABAergic responses were mainly subthreshold and their amplification by persistent sodium conductance was required to trigger APs. AP delays at GABAergic synapses shortened and their variability reduced with an increase in intracellular chloride concentration during whole-cell recordings. Negative shift of the GABA reversal potential (E(GABA)) with low concentrations of bumetanide, or potentiation of GABA(A) receptors with diazepam reduced GDPs amplitude, desynchronized neuronal firing during GDPs and slowed down GDPs propagation. Partial blockade of GABA(A) receptors with bicuculline increased neuronal synchronization and accelerated GDPs propagation. We propose that spike timing at depolarizing GABA synapses is determined by intracellular chloride concentration. At physiological levels of intracellular chloride GABAergic depolarization does not reach the action potential threshold and amplification of GABAergic responses by non-inactivating sodium conductance is required for postsynaptic AP initiation. Slow and variable excitation at GABAergic synapse determines the level of neuronal synchrony and the rate of GDPs propagation in the developing hippocampus.

  8. The clinical analysis of bilateral successive sudden sensorineural hearing loss.

    PubMed

    Wang, Yaowen; Zhang, Litao; Zhang, Jianhua; Zhang, Xuqun; Zhang, Weimin; Chen, Xing; Tang, Shixiong

    2016-11-01

    The objective of this study is to investigate the clinical characteristics of successive bilateral sudden sensorineural hearing loss (SSNHL) with an interval of more than 1 year to aid the evaluation and management of successive bilateral SSNHL (BSSNHL). 14 successive BSSNHL patients and 118 unilateral SSNHL patients with severe and profound hearing loss were reviewed retrospectively. Information about successive BSSNHL was collected included demographics, the intervals between the attacks of bilateral ears, the past medical history, inducing factors, accompanying symptoms, pure-tone tests, blood tests, b-ultrasound examinations of vertebral artery and carotid artery, and medical interventions. And the comparison of improvement rate was made between successive BSSNHL and unilateral SSNHL. SPSS 15.0 was used to analyze the data. In successive BSSNHL, there were six males and eight females; the average aged was 49.86 ± 15.45 years (20-73 years). The interval of the two attacks was 11.43 ± 12.07 years (1-50 years) on average. The onset of treatment was 18.86 ± 12.71 days. Tinnitus was seen in 100 % of the patients, followed by vertigo in 42.85 %, and ear fullness in 21.43 %. 3 of 14 patients described obvious inducing factor: tiredness. Five patients (35.71 %) had hypertension histories, three (21.43 %) had diabetes histories, two (14.29 %) had surgery histories, one (7.14 %) was with depression history, one (7.14 %) was with coronary heart disease history. 30 % (3/10) patients were with atherosclerotic plaque in carotid artery. 4 (28.57 %) patients were with high blood sugar. 8 patients (57.14 %) were with high blood lipids. Thyroid function tests were positive in 27.27 % (3/11) patients. No abnormality was found in antinuclear antibodies titer. The percentage of profound and severe hearing loss were 71.43 and 78.57 % in the recently affected ear and contralateral ear separately. The PTAs of the recently affected ear were 77.14 ± 27.12

  9. Laser performance, thermal focusing and depolarization effects in Nd:Cr:GSGG and Nd:YAG

    NASA Technical Reports Server (NTRS)

    Williams-Byrd, Julie A.; Barnes, Norman P.

    1990-01-01

    The laser performance of Nd:Cr:GSGG and Nd:YAG was investigated and compared for laser efficiency, thermal focusing, and depolarization effects. Laser efficiency was studied for Nd:Cr:GSGG and Nd:YAG under similar conditions. Laser efficiency was measured as a function of electrical energy and output mirror reflectivity. Maximum laser efficiency was calculated by determining the losses in the laser cavity. Thermal focusing and birefringence loss of Nd:Cr:GSGG and Nd:YAG have been examined by varying the average pump power. The average pump power changed by adjusting both the energy per pulse and the pulse-repetition frequency. Substantial thermal focusing differences for Nd:Cr:GSGG are explained.

  10. Uranium trioxide behavior during electron energy loss spectroscopy analysis

    NASA Astrophysics Data System (ADS)

    Degueldre, Claude; Alekseev, Evgeny V.

    2015-03-01

    A sample of uranium trioxide (UO3) was produced by focused ion beam (~10 μm×~10 μm×<0.5 μm) for transmission electron and electron energy loss (EEL) spectroscopy examinations in a transmission electron microscope (TEM). The EEL spectra were recorded as a function of the thickness for the P and O edges in the low energy range 0-350 eV and were compared to spectra of UO3 small grains attached to a TEM grid. The EEL spectrum was studied through a range of thicknesses going from ~60 to ~260 nm. The EEL spectra recorded for UO3 are compared with those recorded for UO2. The reduction of UO3 into U4O9 and/or UO2 is readily observed apparently during the TEM investigations and as confirmed by electron diffraction (eD). This redox effect is similar to that known for other redox sensitive oxides. Recommendations are suggested to avoid sample decomposition.

  11. Time/Loss Analysis in the development and evaluation of emergency response procedures

    SciTech Connect

    Francis, A.A.

    1994-08-01

    Time/Loss Analysis (T/LA) provides a standard for conducting technically consistent and objective evaluations of emergency response planning and procedures. T/LA is also a sound tool for evaluating the performance of safeguards and procedures.

  12. Potent inhibition of anoxic depolarization by the sodium channel blocker dibucaine

    PubMed Central

    Douglas, Heather A.; Callaway, Jennifer K.; Sword, Jeremy; Kirov, Sergei A.

    2011-01-01

    Recurring waves of peri-infarct depolarizations (PIDs) propagate across gray matter in the hours and days following stroke, expanding the primary site of injury. Ischemic depolarization (termed anoxic depolarization or AD in live brain slices) is PID-like but immediately arises in the more metabolically compromised ischemic core. This causes dramatic neuronal and astrocyte swelling and dendritic beading with spine loss within minutes, resulting in acute cell death. AD is evoked in rodent neocortical slices by suppressing the Na+/K+-ATPase pump with either oxygen/glucose deprivation (OGD) or exposure to ouabain. The process driving AD and PIDs remains poorly understood. Here we show that dibucaine is a potent drug inhibiting AD because of its high binding affinity to the Na+ channel. Field recording reveals that, when superfused with ouabain (5 min), neocortical slices pretreated with 1 μM dibucaine for 45 min display either no AD or delayed AD onset compared with untreated controls. If ouabain exposure is extended to 10 min, 1 μM dibucaine is still able to delay AD onset by ∼60%. Likewise, it delays OGD-evoked AD onset by ∼54% but does not depress action potentials (APs) or evoked orthodromic field potentials. Increasing dibucaine to 10 μM inhibits AP firing, gradually putting the slice into a stasis that inhibits AD onset but also renders the slice functionally quiescent. Two-photon microscopy reveals that 10 μM dibucaine pretreatment prevents or helps reverse ouabain-induced structural neuronal damage. Although the therapeutic range of dibucaine is quite narrow, dibucaine-like drugs could prove therapeutically useful in inhibiting PIDs and their resultant neuronal damage. PMID:21273307

  13. Analysis and identification of influential phenomena on iron losses in embedded permanent magnet synchronous machine

    NASA Astrophysics Data System (ADS)

    Breznik, Mitja; Goričan, Viktor; Hamler, Anton; Čorović, Selma; Miljavec, Damijan

    2017-01-01

    This paper presents magnetic flux density behaviour in laminated electrical sheets which affects the results and precision of iron losses calculation in imbedded permanent magnet (IPM) machine. Objective of the research was to analyse all the influential phenomena that were identified through iron loss models analysis, finite element method simulations and iron loss measurements. The presence of phenomena such as harmonic content and rotational magnetic fields are confirmed with finite element method analysis of concentrated and distributed winding IPM machine. A significant magnetic flux density ripple in the rotor of concentrated winding IPM machine in comparison to distributed winding IPM machine is revealed and analysed. Behaviour that affects iron loss in the rotor of synchronous machines in the absence of first order harmonic is analysed. The DC level added to alternating magnetic flux density was used in experiment to mimic magnetic behaviour on the rotor of IPM machine and further to calculate iron losses.

  14. Entropy Generation/Availability Energy Loss Analysis Inside MIT Gas Spring and "Two Space" Test Rigs

    NASA Technical Reports Server (NTRS)

    Ebiana, Asuquo B.; Savadekar, Rupesh T.; Patel, Kaushal V.

    2006-01-01

    The results of the entropy generation and availability energy loss analysis under conditions of oscillating pressure and oscillating helium gas flow in two Massachusetts Institute of Technology (MIT) test rigs piston-cylinder and piston-cylinder-heat exchanger are presented. Two solution domains, the gas spring (single-space) in the piston-cylinder test rig and the gas spring + heat exchanger (two-space) in the piston-cylinder-heat exchanger test rig are of interest. Sage and CFD-ACE+ commercial numerical codes are used to obtain 1-D and 2-D computer models, respectively, of each of the two solution domains and to simulate the oscillating gas flow and heat transfer effects in these domains. Second law analysis is used to characterize the entropy generation and availability energy losses inside the two solution domains. Internal and external entropy generation and availability energy loss results predicted by Sage and CFD-ACE+ are compared. Thermodynamic loss analysis of simple systems such as the MIT test rigs are often useful to understand some important features of complex pattern forming processes in more complex systems like the Stirling engine. This study is aimed at improving numerical codes for the prediction of thermodynamic losses via the development of a loss post-processor. The incorporation of loss post-processors in Stirling engine numerical codes will facilitate Stirling engine performance optimization. Loss analysis using entropy-generation rates due to heat and fluid flow is a relatively new technique for assessing component performance. It offers a deep insight into the flow phenomena, allows a more exact calculation of losses than is possible with traditional means involving the application of loss correlations and provides an effective tool for improving component and overall system performance.

  15. Numerical Analysis of Permittivity with Loss in Isotropic Binary Composites

    DTIC Science & Technology

    1992-06-01

    and higher breakdown r(m’V,.(tcO,. This report describes the numerical analysis of permittivity in iso- t-rojif. Honary composite dielectrics through...are numbered sequentially from the ground electrode and in relation to (x,y,z) coordinate location. The h node number is i = x + (y-l) Xm + (z-l) Xm Ym...6 N L .4 0 2 aB .2 .3 4 .5 .6 7 a 9 1 H Uclume fraction Figure 9. Two-dimensional composite mixture, A-windowed, with constituent permittivities of E

  16. Effect of extreme data loss on heart rate signals quantified by entropy analysis

    NASA Astrophysics Data System (ADS)

    Li, Yu; Wang, Jun; Li, Jin; Liu, Dazhao

    2015-02-01

    The phenomenon of data loss always occurs in the analysis of large databases. Maintaining the stability of analysis results in the event of data loss is very important. In this paper, we used a segmentation approach to generate a synthetic signal that is randomly wiped from data according to the Gaussian distribution and the exponential distribution of the original signal. Then, the logistic map is used as verification. Finally, two methods of measuring entropy-base-scale entropy and approximate entropy-are comparatively analyzed. Our results show the following: (1) Two key parameters-the percentage and the average length of removed data segments-can change the sequence complexity according to logistic map testing. (2) The calculation results have preferable stability for base-scale entropy analysis, which is not sensitive to data loss. (3) The loss percentage of HRV signals should be controlled below the range (p = 30 %), which can provide useful information in clinical applications.

  17. Food loss rate in food supply chain using material flow analysis.

    PubMed

    Ju, Munsol; Osako, Masahiro; Harashina, Sachihiko

    2017-03-01

    The food loss rate is a factor that represents food consumption efficiency. To improve food consumption efficiency, we need to fundamentally quantify food loss at national and global levels. This study examines food and food waste flow and calculates the food loss rate in the food supply chain by targeting Japan. We analyzed inedible food waste and avoidable food losses in wholesale, manufacturing, retail, food services, and households and considered different supply chain pathways, different food categories representing whole Japanese meals, and weight changes after cooking. The results are as follows: (1) Japan has an overall rate of avoidable food losses of approximately 15% for meals (excluding agricultural losses), (2) the supply sector with the highest food loss rate is food services, and (3) the food category with the highest food loss rate is vegetables. Finally, we proposed a model for calculating food loss rates that could be used for future analysis in Japan or other countries. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. High-Precision Calibration of Electron Beam Energy from the Hefei Light Source Using Spin Resonant Depolarization

    NASA Astrophysics Data System (ADS)

    Lan, Jie-Qin; Xu, Hong-Liang

    2014-12-01

    The electron beam energy at the Hefei Light Source (HLS) in the National Synchrotron Radiation Laboratory is highly precisely calibrated by using the method of spin resonant depolarization for the first time. The spin tune and the beam energy are determined by sweeping the frequency of a radial rf stripline oscillating magnetic field to artificially excite a spin resonance and depolarize the beam. The resonance signal is recognized by observing the sudden change of the Touschek loss counting rate of the beam. The possible systematic errors of the experiment are presented and the accuracy of the calibrated energy is shown to be about 10-4. A series of measurements show that the energy stability of the machine is of the order of 9 × 10-3.

  19. Loss of Situation Awareness in Pilots: Analysis of Incident Reports

    NASA Technical Reports Server (NTRS)

    Villeda, Eric B.

    1996-01-01

    Introduction Approximately 75% of all aviation accidents and incidents are attributable to human failures in monitoring, managing, and operating system. Tactical decision errors were found to be a factor in 25 of 37 major US air transport accidents between 1978 and 1990. These two facts demonstrate the inability of some pilots to maintain situation awareness. Situation awareness (SA) is defined as 'the perception of elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future". Thus, when a pilot loses SA, he or she is unable to ether perceive, comprehend, or project the status of the aircraft. In pilots terms, he or she has 'fallen behind the airplane'. Our study this summer involved an analysis of 190 NASA Aviation Safety Reporting System (ASRS) reports.

  20. Depolarization block of neurons during maintenance of electrographic seizures.

    PubMed

    Bikson, Marom; Hahn, Philip J; Fox, John E; Jefferys, John G R

    2003-10-01

    Epileptic seizures are associated with neuronal hyperactivity. Here, however, we investigated whether continuous neuronal firing is necessary to maintain electrographic seizures. We studied a class of "low-Ca2+" ictal epileptiform bursts, induced in rat hippocampal slices, that are characterized by prolonged (2-15 s) interruptions in population spike generation. We found that, during these interruptions, neuronal firing was suppressed rather than desynchronized. Intracellular current injection, application of extracellular uniform electric fields, and antidromic stimulation showed that the source of action potential disruption was depolarization block. The duration of the extracellular potassium transients associated with each ictal burst was not affected by disruptions in neuronal firing. Application of phenytoin or veratridine indicated a critical role for the persistent sodium current in maintaining depolarization block. Our results show that continuous neuronal firing is not necessary for the maintenance of experimental electrographic seizures.

  1. Quantum stabilizer codes for correlated and asymmetric depolarizing errors

    SciTech Connect

    Cafaro, Carlo; Mancini, Stefano

    2010-07-15

    We study the performance of common quantum stabilizer codes in the presence of asymmetric and correlated errors. Specifically, we consider the depolarizing noisy quantum memory channel and perform quantum error correction via the five- and seven-qubit stabilizer codes. We characterize these codes by means of the entanglement fidelity as a function of the error probability and the degree of memory. We show that their performances are lowered by the presence of correlations, and we compute the error probability threshold values for code effectiveness. Furthermore, we uncover that the asymmetry in the error probabilities does not affect the performance of the five-qubit code, while it does affect the performance of the seven-qubit code, which results in being less effective when considering correlated and symmetric depolarizing errors but more effective for correlated and asymmetric errors.

  2. Unexpectedly wide rf-induced synchrotron sideband depolarizing resonances

    NASA Astrophysics Data System (ADS)

    Chu, C. M.; Ellison, T. J.; Lee, S. Y.; Rinckel, T.; Schwandt, P.; Sperisen, F.; von Przewoski, B.; Anferov, V. A.; Blinov, B. B.; Bychkov, M. A.; Caussyn, D. D.; Courant, E. D.; Crandell, D. A.; Derbenev, Ya. S.; Kaufman, W. A.; Krisch, A. D.; Lorenzon, W.; Nurushev, T. S.; Phelps, R. A.; Ratner, L. G.; Wong, V. K.; Ohmori, C.; Minty, M. G.; Martin, P. S.; Russell, A. D.; Sivers, D. W.

    1998-10-01

    Using an rf solenoid magnet, we studied the depolarization of a stored 104.1 MeV vertically polarized proton beam. The two primary rf depolarizing resonances were properly centered around the protons' circulation frequency fc, at fc(3-νs) and fc(νs-1), where νs is the spin tune; moreover, each resonance was roughly consistent with the expected width of about 720 Hz. Each primary rf resonance had two synchrotron sideband resonances at the expected frequencies. The two νs-1 sidebands were deep dips while the two 3-νs sidebands were very shallow; this was not expected. Moreover, all four sideband resonances were unexpectedly wider than the two primary resonances.

  3. Transient Contraction of Mitochondria Induces Depolarization through the Inner Membrane Dynamin OPA1 Protein*

    PubMed Central

    Lee, Hakjoo; Yoon, Yisang

    2014-01-01

    Dynamin-related membrane remodeling proteins regulate mitochondrial morphology by mediating fission and fusion. Although mitochondrial morphology is considered an important factor in maintaining mitochondrial function, a direct mechanistic link between mitochondrial morphology and function has not been defined. We report here a previously unrecognized cellular process of transient contraction of the mitochondrial matrix. Importantly, we found that this transient morphological contraction of mitochondria is accompanied by a reversible loss or decrease of inner membrane potential. Fission deficiency greatly amplified this phenomenon, which functionally exhibited an increase of inner membrane proton leak. We found that electron transport activity is necessary for the morphological contraction of mitochondria. Furthermore, we discovered that silencing the inner membrane-associated dynamin optic atrophy 1 (OPA1) in fission deficiency prevented mitochondrial depolarization and decreased proton leak without blocking mitochondrial contraction, indicating that OPA1 is a factor in coupling matrix contraction to mitochondrial depolarization. Our findings show that transient matrix contraction is a novel cellular mechanism regulating mitochondrial activity through the function of the inner membrane dynamin OPA1. PMID:24627489

  4. SARM1 and TRAF6 bind to and stabilize PINK1 on depolarized mitochondria

    PubMed Central

    Murata, Hitoshi; Sakaguchi, Masakiyo; Kataoka, Ken; Huh, Nam-ho

    2013-01-01

    Mutations in PTEN-induced putative kinase 1 (PINK1) or parkin cause autosomal recessive forms of Parkinson's disease. Recent work suggests that loss of mitochondrial membrane potential stabilizes PINK1 and that accumulated PINK1 recruits parkin from the cytoplasm to mitochondria for elimination of depolarized mitochondria, which is known as mitophagy. In this study, we find that PINK1 forms a complex with sterile α and TIR motif containing 1 (SARM1) and tumor necrosis factor receptor–associated factor 6 (TRAF6), which is important for import of PINK1 in the outer membrane and stabilization of PINK1 on depolarized mitochondria. SARM1, which is known to be an adaptor protein for Toll-like receptor, binds to PINK1 and promotes TRAF6-mediated lysine 63 chain ubiquitination of PINK1 at lysine 433. Down-regulation of SARM1 and TRAF6 abrogates accumulation of PINK1, followed by recruitment of parkin to damaged mitochondria. Some pathogenic mutations of PINK1 reduce the complex formation and ubiquitination. These results indicate that association of PINK1 with SARM1 and TRAF6 is an important step for mitophagy. PMID:23885119

  5. Overcoming an intrinsic depolarizing resonance with a partial snake at the Brookhaven AGS.

    SciTech Connect

    Huang, H.; Ahrens, L.; Bai, M.; Brown, K. A.; Glenn, W.; Luccio, A. U.; MacKay, W. W.; Montag, C.; Ptitsyn, V.; Roser, T.; Tsoupas, N.; Zeno, K.; Ranjbar, V.; Cadman, R. V.; Spinka, H.; Underwood, D.; High Energy Physics; BNL; Indiana Univ.

    2004-06-01

    An 11.4% partial Siberian snake was used to successfully accelerate polarized protons through a strong intrinsic depolarizing spin resonance in the Alternating Gradient Synchrotron (AGS). No noticeable depolarization was observed. This opens up the possibility of using a 20% to 30% partial Siberian snake in the AGS or other medium energy proton synchrotrons to overcome all weak and strong depolarizing spin resonances.

  6. Altered hypermetabolic response to cortical spreading depolarizations after traumatic brain injury in rats.

    PubMed

    Balança, Baptiste; Meiller, Anne; Bezin, Laurent; Dreier, Jens P; Marinesco, Stéphane; Lieutaud, Thomas

    2017-05-01

    Spreading depolarizations are waves of near-complete breakdown of neuronal transmembrane ion gradients, free energy starving, and mass depolarization. Spreading depolarizations in electrically inactive tissue are associated with poor outcome in patients with traumatic brain injury. Here, we studied changes in regional cerebral blood flow and brain oxygen (PbtO2), glucose ([Glc]b), and lactate ([Lac]b) concentrations in rats, using minimally invasive real-time sensors. Rats underwent either spreading depolarizations chemically triggered by KCl in naïve cortex in absence of traumatic brain injury or spontaneous spreading depolarizations in the traumatic penumbra after traumatic brain injury, or a cluster of spreading depolarizations triggered chemically by KCl in a remote window from which spreading depolarizations invaded penumbral tissue. Spreading depolarizations in noninjured cortex induced a hypermetabolic response characterized by a decline in [Glc]b and monophasic increases in regional cerebral blood flow, PbtO2, and [Lac]b, indicating transient hyperglycolysis. Following traumatic brain injury, spontaneous spreading depolarizations occurred, causing further decline in [Glc]b and reducing the increase in regional cerebral blood flow and biphasic responses of PbtO2 and [Lac]b, followed by prolonged decline. Recovery of PbtO2 and [Lac]b was significantly delayed in traumatized animals. Prespreading depolarization [Glc]b levels determined the metabolic response to clusters. The results suggest a compromised hypermetabolic response to spreading depolarizations and slower return to physiological conditions following traumatic brain injury-induced spreading depolarizations.

  7. Depolarization of rotational angular momentum in CN(A2Π, v = 4) + Ar collisions.

    PubMed

    McGurk, S J; McKendrick, K G; Costen, M L; Bennett, D I G; Kłos, J; Alexander, M H; Dagdigian, P J

    2012-04-28

    Angular momentum depolarization and population transfer in CN(A(2)Π, v = 4, j, F(1)e) + Ar collisions have been investigated both experimentally and theoretically. Ground-state CN(X(2)Σ(+)) molecules were generated by pulsed 266-nm laser photolysis of ICN in a thermal (nominally 298 K) bath of the Ar collision partner at a range of pressures. The translationally thermalized CN(X) radicals were optically pumped to selected unique CN(A(2)Π, v = 4, j = 2.5, 3.5, 6.5, 11.5, 13.5, and 18.5, F(1)e) levels on the A-X (4,0) band by a pulsed tunable dye laser. The prepared level was monitored in a collinear geometry by cw frequency-modulated (FM) spectroscopy in stimulated emission on the CN(A-X) (4,2) band. The FM lineshapes for co- and counter-rotating circular pump and probe polarizations were analyzed to extract the time dependence of the population and (to a good approximation) orientation (tensor rank K = 1 polarization). The corresponding parallel and perpendicular linear polarizations yielded population and alignment (K = 2). The combined population and polarization measurements at each Ar pressure were fitted to a 3-level kinetic model, the minimum complexity necessary to reproduce the qualitative features of the data. Rate constants were extracted for the total loss of population and of elastic depolarization of ranks K = 1 and 2. Elastic depolarization is concluded to be a relatively minor process in this system. Complementary full quantum scattering (QS) calculations were carried out on the best previous and a new set of ab initio potential energy surfaces for CN(A)-Ar. Collision-energy-dependent elastic tensor and depolarization cross sections for ranks K = 1 and 2 were computed for CN(A(2)Π, v = 4, j = 1.5-10.5, F(1)e) rotational/fine-structure levels. In addition, integral cross sections for rotationally inelastic transitions out of these levels were computed and summed to yield total population transfer cross sections. These quantities were integrated

  8. Muscarinic Depolarization of Layer II Neurons of the Parasubiculum

    PubMed Central

    Glasgow, Stephen D.; Chapman, C. Andrew

    2013-01-01

    The parasubiculum (PaS) is a component of the hippocampal formation that sends its major output to layer II of the entorhinal cortex. The PaS receives strong cholinergic innervation from the basal forebrain that is likely to modulate neuronal excitability and contribute to theta-frequency network activity. The present study used whole cell current- and voltage-clamp recordings to determine the effects of cholinergic receptor activation on layer II PaS neurons. Bath application of carbachol (CCh; 10–50 µM) resulted in a dose-dependent depolarization of morphologically-identified layer II stellate and pyramidal cells that was not prevented by blockade of excitatory and inhibitory synaptic inputs. Bath application of the M1 receptor antagonist pirenzepine (1 µM), but not the M2-preferring antagonist methoctramine (1 µM), blocked the depolarization, suggesting that it is dependent on M1 receptors. Voltage-clamp experiments using ramped voltage commands showed that CCh resulted in the gradual development of an inward current that was partially blocked by concurrent application of the selective Kv7.2/3 channel antagonist XE-991, which inhibits the muscarine-dependent K+ current IM. The remaining inward current also reversed near EK and was inhibited by the K+ channel blocker Ba2+, suggesting that M1 receptor activation attenuates both IM as well as an additional K+ current. The additional K+ current showed rectification at depolarized voltages, similar to K+ conductances mediated by Kir 2.3 channels. The cholinergic depolarization of layer II PaS neurons therefore appears to occur through M1-mediated effects on IM as well as an additional K+ conductance. PMID:23520542

  9. Elastodynamic metasurface: Depolarization of mechanical waves and time effects

    SciTech Connect

    Boutin, Claude; Schwan, Logan; Dietz, Matthew S.

    2015-02-14

    We report the concept of microstructured surfaces with inner resonance in the field of elastodynamics, so-called elastodynamic metasurfaces. Such metasurfaces allow for wavefield manipulation of mechanical waves by tuning the boundary conditions at specific frequencies. In particular, they can be used to depolarize elastic waves without introducing heterogeneities in the medium itself; the physical means to do so in homogeneous elastic media used to remain, surprisingly, an open question while depolarization is commonplace in electromagnetism. The principle relies on the anisotropic behaviour of a subwavelength array of resonators: Their subwavelength configuration confines the Bragg interferences scattered by resonators into a boundary layer. The effective behaviour of the resonating array is expressed with homogenization as an unconventional impedance, the frequency-dependence, and anisotropy of which lead to depolarization and time effects. The concept of the elastodynamic metasurface is tested experimentally and results bear testament to its efficacy and robustness. Elastodynamic metasurfaces are easily realized and analytically predictable, opening new possibilities in tomography techniques, ultrasonics, geophysics, vibration control, materials and structure design.

  10. Elastodynamic metasurface: Depolarization of mechanical waves and time effects

    NASA Astrophysics Data System (ADS)

    Boutin, Claude; Schwan, Logan; Dietz, Matthew S.

    2015-02-01

    We report the concept of microstructured surfaces with inner resonance in the field of elastodynamics, so-called elastodynamic metasurfaces. Such metasurfaces allow for wavefield manipulation of mechanical waves by tuning the boundary conditions at specific frequencies. In particular, they can be used to depolarize elastic waves without introducing heterogeneities in the medium itself; the physical means to do so in homogeneous elastic media used to remain, surprisingly, an open question while depolarization is commonplace in electromagnetism. The principle relies on the anisotropic behaviour of a subwavelength array of resonators: Their subwavelength configuration confines the Bragg interferences scattered by resonators into a boundary layer. The effective behaviour of the resonating array is expressed with homogenization as an unconventional impedance, the frequency-dependence, and anisotropy of which lead to depolarization and time effects. The concept of the elastodynamic metasurface is tested experimentally and results bear testament to its efficacy and robustness. Elastodynamic metasurfaces are easily realized and analytically predictable, opening new possibilities in tomography techniques, ultrasonics, geophysics, vibration control, materials and structure design.

  11. Cellular contraction precedes membrane depolarization in Vorticella convallaria

    PubMed

    Shiono; Naitoh

    1997-01-01

    Application of a mechanical stimulus to the cell body of the peritrich ciliate Vorticella convallaria evoked an all-or-nothing membrane depolarization, the large pulse. This was always accompanied by an all-or-nothing cellular contraction, and simultaneous recordings of the two events revealed that the large pulse was always preceded by the cellular contraction. A smaller graded membrane depolarization (the medium pulse) was sometimes produced in response to a weaker mechanical stimulus. The medium pulse was accompanied by a small, graded, localized contraction of the cell body and was occasionally followed by a large pulse. When a large pulse occurred during a medium pulse, it reached the same peak level as that of a large pulse evoked without a preceding medium pulse. When a medium pulse occurred during a medium pulse, summation of the two pulses was observed. Sustained contraction causes V. convallaria to become rounded, and in this state a mechanical stimulus stronger than that used to evoke the large pulse evoked a graded depolarizing mechanoreceptor potential in the cell. We conclude that both the large and medium pulses are caused by an inward receptor current that is activated mechanically following contraction of the cell body. A localized contraction evokes a small mechanoreceptor current, causing a medium pulse. An all-or-nothing contraction evokes a saturated, all-or-nothing mechanoreceptor current, causing a large pulse.

  12. Dual Double-Wedge Pseudo-Depolarizer with Anamorphic PSF

    NASA Technical Reports Server (NTRS)

    Hill, Peter; Thompson, Patrick

    2012-01-01

    A polarized scene, which may occur at oblique illumination angles, creates a radiometric signal that varies as a function of viewing angle. One common optical component that is used to minimize such an effect is a polarization scrambler or depolarizer. As part of the CLARREO mission, the SOLARIS instrument project at Goddard Space Flight Center has developed a new class of polarization scramblers using a dual double-wedge pseudo-depolarizer that produces an anamorphic point spread function (PSF). The SOLARIS instrument uses two Wollaston type scramblers in series, each with a distinct wedge angle, to image a pseudo-depolarized scene that is free of eigenstates. Since each wedge is distinct, the scrambler is able to produce an anamorphic PSF that maintains high spatial resolution in one dimension by sacrificing the spatial resolution in the other dimension. This scrambler geometry is ideal for 1-D imagers, such as pushbroom slit spectrometers, which require high spectral resolution, high spatial resolution, and low sensitivity to polarized light. Moreover, the geometry is applicable to a wide range of scientific instruments that require both high SNR (signal-to-noise ratio) and low sensitivity to polarized scenes

  13. Migraine Mutations Increase Stroke Vulnerability by Facilitating Ischemic Depolarizations

    PubMed Central

    Eikermann-Haerter, Katharina; Lee, Jeong Hyun; Yuzawa, Izumi; Liu, Christina H.; Zhou, Zhipeng; Shin, Hwa Kyoung; Zheng, Yi; Qin, Tao; Kurth, Tobias; Waeber, Christian; Ferrari, Michel D.; van den Maagdenberg, Arn M. J. M.; Moskowitz, Michael A.; Ayata, Cenk

    2012-01-01

    Background Migraine is an independent risk factor for stroke. Mechanisms underlying this association are unclear. Familial hemiplegic migraine (FHM), a migraine subtype that also carries an increased stroke risk, is a useful model for common migraine phenotypes because of shared aura and headache features, trigger factors, and underlying glutamatergic mechanisms. Methods and Results Here, we show that FHM type 1 (FHM1) mutations in CaV2.1 voltage-gated Ca2+ channels render the brain more vulnerable to ischemic stroke. Compared to wild-type, two FHM1 mutant mouse strains developed earlier onset of anoxic depolarization and more frequent peri-infarct depolarizations, associated with rapid expansion of infarct core on diffusion-weighted MRI and larger perfusion deficits on laser speckle flowmetry. Cerebral blood flow required for tissue survival was higher in the mutants, leading to infarction with milder ischemia. As a result, mutants developed larger infarcts and worse neurological outcomes after stroke, which were selectively attenuated by a glutamate receptor antagonist. Conclusions We propose that enhanced susceptibility to ischemic depolarizations akin to spreading depression predisposes migraineurs to infarction during mild ischemic events, thereby increasing the stroke risk. PMID:22144569

  14. Analysis and experiment of eddy current loss in Homopolar magnetic bearings with laminated rotor cores

    NASA Astrophysics Data System (ADS)

    Jinji, Sun; Dong, Chen

    2013-08-01

    This paper analyses the eddy current loss in Homopolar magnetic bearings with laminated rotor cores produced by the high speed rotation in order to reduce the power loss for the aerospace applications. The analytical model of rotational power loss is proposed in Homopolar magnetic bearings with laminated rotor cores considering the magnetic circuit difference between Homopolar and Heteropolar magnetic bearings. Therefore, the eddy current power loss can be calculated accurately using the analytical model by magnetic field solutions according to the distribution of magnetic fields around the pole surface and boundary conditions at the surface of the rotor cores. The measurement method of rotational power loss in Homopolar magnetic bearing is proposed, and the results of the theoretical analysis are verified by experiments in the prototype MSCMG. The experimental results show the correctness of calculation results.

  15. Quantifying Biodiversity Losses Due to Human Consumption: A Global-Scale Footprint Analysis.

    PubMed

    Wilting, Harry C; Schipper, Aafke M; Bakkenes, Michel; Meijer, Johan R; Huijbregts, Mark A J

    2017-03-21

    It is increasingly recognized that human consumption leads to considerable losses of biodiversity. This study is the first to systematically quantify these losses in relation to land use and greenhouse gas (GHG) emissions associated with the production and consumption of (inter)nationally traded goods and services by presenting consumption-based biodiversity losses, in short biodiversity footprint, for 45 countries and world regions globally. Our results showed that (i) the biodiversity loss per citizen shows large variations among countries, with higher values when per-capita income increases; (ii) the share of biodiversity losses due to GHG emissions in the biodiversity footprint increases with income; (iii) food consumption is the most important driver of biodiversity loss in most of the countries and regions, with a global average of 40%; (iv) more than 50% of the biodiversity loss associated with consumption in developed economies occurs outside their territorial boundaries; and (v) the biodiversity footprint per dollar consumed is lower for wealthier countries. The insights provided by our analysis might support policymakers in developing adequate responses to avert further losses of biodiversity when population and incomes increase. Both the mitigation of GHG emissions and land use related reduction options in production and consumption should be considered in strategies to protect global biodiversity.

  16. Young Stroke Mortality in Fiji Islands: An Economic Analysis of National Human Capital Resource Loss

    PubMed Central

    Maharaj, Jagdish C.; Reddy, Mahendra

    2012-01-01

    Introduction. The objective of this study was to perform an economic analysis in terms of annual national human capital resource loss from young stroke mortality in Fiji. The official retirement age is 55 years in Fiji. Method. Stroke mortality data, for working-age group 15–55 years, obtained from the Ministry of Health and per capita national income figure for the same year was utilised to calculate the total output loss for the economy. The formula of output loss from the economy was used. Results. There were 273 stroke deaths of which 53.8% were of working-age group. The annual national human capital loss from stroke mortality for Fiji for the year was calculated to be F$8.85 million (US$5.31 million). The highest percentage loss from stroke mortality was from persons in their forties; that is, they still had more then 10 years to retirement. Discussion. This loss equates to one percent of national government revenue and 9.7% of Ministry of Health budget for the same year. The annual national human capital loss from stroke mortality is an important dimension in the overall economic equation of total economic burden of stroke. Conclusion. This study demonstrates a high economic burden for Fiji from stroke mortality of young adults in terms of annual national human capital loss. PMID:22778993

  17. Polarization changes at Lyot depolarizer output for different types of input beams.

    PubMed

    de Sande, J Carlos G; Piquero, Gemma; Teijeiro, Cristina

    2012-03-01

    Lyot depolarizers are optical devices made of birefringent materials used for producing unpolarized beams from totally polarized incident light. The depolarization is produced for polychromatic input beams due to the different phase introduced by the Lyot depolarizer for each wavelength. The effect of this device on other types of incident fields is investigated. In particular two cases are analyzed: (i) monochromatic and nonuniformly polarized incident beams and (ii) incident light synthesized by superposition of two monochromatic orthogonally polarized beams with different wavelengths. In the last case, it is theoretically and experimentally shown that the Lyot depolarizer increases the degree of polarization instead of depolarizes.

  18. Interaction between gustatory depolarizing receptor potential and efferent-induced slow depolarizing synaptic potential in frog taste cell.

    PubMed

    Sato, Toshihide; Nishishita, Kazuhisa; Okada, Yukio; Toda, Kazuo

    2009-03-01

    Electrical stimulation of parasympathetic nerve (PSN) efferent fibers in the glossopharyngeal nerve induced a slow depolarizing synaptic potential (DSP) in frog taste cells under hypoxia. The objective of this study is to examine the interaction between a gustatory depolarizing receptor potential (GDRP) and a slow DSP. The amplitude of slow DSP added to a tastant-induced GDRP of 10 mV was suppressed to 60% of control slow DSPs for NaCl and acetic acid stimulations, but to 20-30% for quinine-HCl (Q-HCl) and sucrose stimulations. On the other hand, when a GDRP was induced during a prolonged slow DSP, the amplitude of GDRPs induced by 1 M NaCl and 1 M sucrose was suppressed to 50% of controls, but that by 1 mM acetic acid and 10 mM Q-HCl unchanged. It is concluded that the interaction between GDRPs and efferent-induced slow DSPs in frog taste cells under hypoxia derives from the crosstalk between a gustatory receptor current across the receptive membrane and a slow depolarizing synaptic current across the proximal subsynaptic membrane of taste cells.

  19. Association between Tooth Loss and Gastric Cancer: A Meta-Analysis of Observational Studies

    PubMed Central

    Luo, Hong; Zhao, Ke; Huang, Guang-Lei; Luo, Si-Yang; Peng, Ju-Xiang; Song, Ju-Kun

    2016-01-01

    Observational studies showed that tooth loss is associated with gastric cancer, but the findings are inconsistent. In this study, a meta-analysis was conducted to evaluate the relationship between tooth loss and gastric cancer. Relevant studies were screened in PubMed and Embase databases, and nine observational studies were considered eligible for the analysis. The combined relative risks for the highest versus the lowest categories of tooth loss were 1.86 (95% CI: 1.08–3.21) and 1.31 (95% CI: 1.12–1.53) in case control and cohort studies, respectively. However, unstable results were observed in the stratified and sensitivity analysis. The current evidence, based solely on four case-control studies and five cohort studies, suggested that tooth loss is a potential marker of gastric cancer. However, we can not concluded at this time that tooth loss may be a risk factor for gastric cancer due to significant heterogeneity among studies and mixed results between case-control studies and cohort studies. Additional large-scale and high-quality prospective studies are required to evaluate the association between tooth loss and risk of gastric cancer. PMID:26934048

  20. Weight loss, appetite loss and food intake in cancer patients with cancer cachexia: three peas in a pod? - analysis from a multicenter cross sectional study.

    PubMed

    Solheim, Tora S; Blum, David; Fayers, Peter M; Hjermstad, Marianne J; Stene, Guro B; Strasser, Florian; Kaasa, Stein

    2014-04-01

    How to assess cachexia is a barrier both in research and in clinical practice. This study examines the need for assessing both reduced food intake and loss of appetite, to see if these variables can be used interchangeably. A secondary aim is to assess the variance explained by food intake, appetite and weight loss by using tumor-related factors, symptoms and biological markers as explanatory variables. One thousand and seventy patients with incurable cancer were registered in an observational, cross sectional multicenter study. A total of 885 patients that had complete data on food intake (PG-SGA), appetite (EORTC QLQ-C30) and weight loss were included in the present analysis. The association between reduced food intake and appetite loss was assessed using Spearman's correlation. To find the explained variance of the three symptoms a multivariate analysis was performed. The mean age was 62 years with a mean survival of 247 days and a mean Karnofsky performance status of 72. Thirteen percent of the patients who reported eating less than normal had good appetite and 25% who had unchanged or increased food intake had reduced appetite. Correlation between appetite loss and food intake was 0.50. Explained variance for the regression models was 44% for appetite loss, 27% for food intake and only 13% for weight loss. Both appetite loss and food intake should be assessed in cachectic patients since conscious control of eating may sometimes overcome appetite loss. The low explained variance for weight loss is probably caused by the need for more knowledge about metabolism and inflammation, and is consistent with the cancer cachexia definition that claims that in cachexia weight loss is not caused by reduced food intake alone. The questions concerning appetite loss from EORTC-QLQ C30 and food intake from PG-SGA seem practical and informative when dealing with advanced cancer patients.

  1. Oxygen availability and spreading depolarizations provide complementary prognostic information in neuromonitoring of aneurysmal subarachnoid hemorrhage patients.

    PubMed

    Winkler, Maren Kl; Dengler, Nora; Hecht, Nils; Hartings, Jed A; Kang, Eun J; Major, Sebastian; Martus, Peter; Vajkoczy, Peter; Woitzik, Johannes; Dreier, Jens P

    2017-05-01

    Multimodal neuromonitoring in neurocritical care increasingly includes electrocorticography to measure epileptic events and spreading depolarizations. Spreading depolarization causes spreading depression of activity (=isoelectricity) in electrically active tissue. If the depression is long-lasting, further spreading depolarizations occur in still isoelectric tissue where no activity can be suppressed. Such spreading depolarizations are termed isoelectric and are assumed to indicate energy compromise. However, experimental and clinical recordings suggest that long-lasting spreading depolarization-induced depression and isoelectric spreading depolarizations are often recorded outside of the actual ischemic zones, allowing the remote diagnosis of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage. Here, we analyzed simultaneous electrocorticography and tissue partial pressure of oxygen recording in 33 aneurysmal subarachnoid hemorrhage patients. Multiple regression showed that both peak total depression duration per recording day and mean baseline tissue partial pressure of oxygen were independent predictors of outcome. Moreover, tissue partial pressure of oxygen preceding spreading depolarization was similar and differences in tissue partial pressure of oxygen responses to spreading depolarization were only subtle between isoelectric spreading depolarizations and spreading depressions. This further supports that, similar to clustering of spreading depolarizations, long spreading depolarization-induced periods of isoelectricity are useful to detect energy compromise remotely, which is valuable because the exact location of future developing pathology is unknown at the time when the neurosurgeon implants recording devices.

  2. Analysis of temperature profiles for investigating stream losses beneath ephemeral channels

    USGS Publications Warehouse

    Constantz, J.; Stewart, A.E.; Niswonger, R.; Sarma, L.

    2002-01-01

    Continuous estimates of streamflow are challenging in ephemeral channels. The extremely transient nature of ephemeral streamflows results in shifting channel geometry and degradation in the calibration of streamflow stations. Earlier work suggests that analysis of streambed temperature profiles is a promising technique for estimating streamflow patterns in ephemeral channels. The present work provides a detailed examination of the basis for using heat as a tracer of stream/groundwater exchanges, followed by a description of an appropriate heat and water transport simulation code for ephemeral channels, as well as discussion of several types of temperature analysis techniques to determine streambed percolation rates. Temperature-based percolation rates for three ephemeral stream sites are compared with available surface water estimates of channel loss for these sites. These results are combined with published results to develop conclusions regarding the accuracy of using vertical temperature profiles in estimating channel losses. Comparisons of temperature-based streambed percolation rates with surface water-based channel losses indicate that percolation rates represented 30% to 50% of the total channel loss. The difference is reasonable since channel losses include both vertical and nonvertical component of channel loss as well as potential evapotranspiration losses. The most significant advantage of the use of sediment-temperature profiles is their robust and continuous nature, leading to a long-term record of the timing and duration of channel losses and continuous estimates of streambed percolation. The primary disadvantage is that temperature profiles represent the continuous percolation rate at a single point in an ephemeral channel rather than an average seepage loss from the entire channel.

  3. Genomic gains and losses in malignant mesothelioma demonstrated by FISH analysis of paraffin-embedded tissues.

    PubMed

    Takeda, Maiko; Kasai, Takahiko; Enomoto, Yasunori; Takano, Masato; Morita, Kouhei; Kadota, Eiji; Iizuka, Norishige; Maruyama, Hiroshi; Nonomura, Akitaka

    2012-01-01

    Malignant mesothelioma (MM) results from the accumulation of a number of acquired genetic events at the onset. In MM, the most frequent changes were losses in 9p21, 1p36, 14q32 and 22q12, and gains in 5p, 7p and 8q24 by comparative genomic hybridisation analysis. Although the diagnostic utility of 9p21 homozygous deletion by fluorescence in situ hybridisation (FISH) analysis in MM has been reported recently, alterations of other genes have not been examined to any great extent. This study analysed the frequency of various genomic gains and losses in MM using FISH analysis. The authors performed a FISH analysis using paraffin-embedded tissues from 42 cases of MM. Chromosomal losses in MM were found at 9p21 (83%), 1p36 (43%), 14q32 (43%) and 22q12 (38%), whereas gains were found at 5p15 (48%), 7p12 (38%) and 8q24 (45%). There were no cases of adenomatoid tumour, benign mesothelial multicystic tumour, reactive mesothelial hyperplasia or pleuritis showing any gains or losses. At least one genomic abnormality was identified in all cases of MM. Among various histological subtypes, the chromosomal abnormality tended to be more common in cases showing sarcomatous elements (biphasic or pure sarcomatoid) than in cases showing an epithelioid histology. The authors found various genomic gains and losses in MM by FISH analysis. The frequency of each genomic gain or loss examined in MM by FISH analysis almost agreed with the comparative genomic hybridisation technique in previous studies. This study suggests that genomic evaluation by FISH analysis might be helpful in distinguishing MM from benign mesothelial proliferation.

  4. Constraining regular and turbulent magnetic field strengths in M 51 via Faraday depolarization

    NASA Astrophysics Data System (ADS)

    Shneider, C.; Haverkorn, M.; Fletcher, A.; Shukurov, A.

    2014-08-01

    We employ an analytical model that incorporates both wavelength-dependent and wavelength-independent depolarization to describe radio polarimetric observations of polarization at λλλ 3.5,6.2,20.5 cm in M 51 (NGC 5194). The aim is to constrain both the regular and turbulent magnetic field strengths in the disk and halo, modeled as a two- or three-layer magneto-ionic medium, via differential Faraday rotation and internal Faraday dispersion, along with wavelength-independent depolarization arising from turbulent magnetic fields. A reduced chi-squared analysis is used for the statistical comparison of predicted to observed polarization maps to determine the best-fit magnetic field configuration at each of four radial rings spanning 2.4 - 7.2 kpc in 1.2 kpc increments. We find that a two-layer modeling approach provides a better fit to the observations than a three-layer model, where the near and far sides of the halo are taken to be identical, although the resulting best-fit magnetic field strengths are comparable. This implies that all of the signal from the far halo is depolarized at these wavelengths. We find a total magnetic field in the disk of approximately 18 μG and a total magnetic field strength in the halo of ~4-6 μG. Both turbulent and regular magnetic field strengths in the disk exceed those in the halo by a factor of a few. About half of the turbulent magnetic field in the disk is anisotropic, but in the halo all turbulence is only isotropic.

  5. Effects of Regional Mitochondrial Depolarization on Electrical Propagation: Implications for Arrhythmogenesis

    PubMed Central

    Zhou, Lufang; Solhjoo, Soroosh; Millare, Brent; Plank, Gernot; Abraham, M. Roselle; Cortassa, Sonia; Trayanova, Natalia; O’Rourke, Brian

    2014-01-01

    Background Sudden cardiac death often involves arrhythmias triggered by metabolic stress. Loss of mitochondrial function is thought to contribute to the arrhythmogenic substrate, but how mitochondria contribute to uncoordinated electrical activity is poorly understood. It has been proposed that the formation of “metabolic current sinks”, caused by the non-uniform collapse of mitochondrial inner-membrane potential (ΔΨm), contributes to reentrant arrhythmias because ΔΨm depolarization is tightly coupled to the activation of sarcolemmal ATP-sensitive K+ (KATP) channels, hastening action potential repolarization and shortening the refractory period. Methods and Results Here we use computational and experimental methods to investigate how ΔΨm instability can induce reentrant arrhythmias. We develop the first tissue level model of cardiac electrical propagation incorporating cellular electrophysiology, excitation-contraction coupling, mitochondrial energetics and reactive oxygen species (ROS) balance. Simulations show that reentry and fibrillation can be initiated by regional ΔΨm loss, due to the disparity of refractory periods inside and outside of the metabolic sink. Computational results are compared with the effects of a metabolic sink generated experimentally by local perfusion of a mitochondrial uncoupler in a monolayer of cardiac myocytes. Conclusions The results demonstrate that regional mitochondrial depolarization triggered by oxidative stress activates sarcolemmal KATP currents to form a metabolic sink. Consequent shortening of the action potential inside, but not outside, the sink increases the propensity for reentry. ΔΨm recovery during pacing can lead to novel mechanisms of ectopic activation. The findings highlight the importance of mitochondria as potential therapeutic targets for sudden death associated with cardiovascular disease. PMID:24382411

  6. Power Loss Analysis and Comparison of Segmented and Unsegmented Energy Coupling Coils for Wireless Energy Transfer

    PubMed Central

    Tang, Sai Chun; McDannold, Nathan J.

    2015-01-01

    This paper investigated the power losses of unsegmented and segmented energy coupling coils for wireless energy transfer. Four 30-cm energy coupling coils with different winding separations, conductor cross-sectional areas, and number of turns were developed. The four coils were tested in both unsegmented and segmented configurations. The winding conduction and intrawinding dielectric losses of the coils were evaluated individually based on a well-established lumped circuit model. We found that the intrawinding dielectric loss can be as much as seven times higher than the winding conduction loss at 6.78 MHz when the unsegmented coil is tightly wound. The dielectric loss of an unsegmented coil can be reduced by increasing the winding separation or reducing the number of turns, but the power transfer capability is reduced because of the reduced magnetomotive force. Coil segmentation using resonant capacitors has recently been proposed to significantly reduce the operating voltage of a coil to a safe level in wireless energy transfer for medical implants. Here, we found that it can naturally eliminate the dielectric loss. The coil segmentation method and the power loss analysis used in this paper could be applied to the transmitting, receiving, and resonant coils in two- and four-coil energy transfer systems. PMID:26640745

  7. Power Loss Analysis and Comparison of Segmented and Unsegmented Energy Coupling Coils for Wireless Energy Transfer.

    PubMed

    Tang, Sai Chun; McDannold, Nathan J

    2015-03-01

    This paper investigated the power losses of unsegmented and segmented energy coupling coils for wireless energy transfer. Four 30-cm energy coupling coils with different winding separations, conductor cross-sectional areas, and number of turns were developed. The four coils were tested in both unsegmented and segmented configurations. The winding conduction and intrawinding dielectric losses of the coils were evaluated individually based on a well-established lumped circuit model. We found that the intrawinding dielectric loss can be as much as seven times higher than the winding conduction loss at 6.78 MHz when the unsegmented coil is tightly wound. The dielectric loss of an unsegmented coil can be reduced by increasing the winding separation or reducing the number of turns, but the power transfer capability is reduced because of the reduced magnetomotive force. Coil segmentation using resonant capacitors has recently been proposed to significantly reduce the operating voltage of a coil to a safe level in wireless energy transfer for medical implants. Here, we found that it can naturally eliminate the dielectric loss. The coil segmentation method and the power loss analysis used in this paper could be applied to the transmitting, receiving, and resonant coils in two- and four-coil energy transfer systems.

  8. [The treatment effects analysis of 164 patients with sudden sensorineural hearing loss].

    PubMed

    Zhang, Wei; Xie, Wen; Xu, Hong; Liu, Yuehui

    2015-05-01

    To explore the effective treatment of sudden sensorineural hearing loss and factors affecting its prognosis. The clinical data and follow-up results of 164 patients with sudden sensorineural hearing loss were analyzed retrospectively. All the 164 patients were given intravenous vasodilator, neurotrophic drugs treatment, oral prednisone treatment, and intratympanic dexamethasone injection. All patients were divided into low frequency hearing loss type,intermediate frequency hearing loss, high frequency hearing loss, all frequency hearing loss and total deafness group. Pure tone hearing threshold test were performed before and 3 months after treatment. All patients and different groups were compared before and after treatment damage frequency of average air conduction and various frequency air conduction hearing. Analysis of gender, age, process and hearing curve type, frequency hearing of impaired before treatment, the symptoms with or without vertigo. All the patients' hearing improved after treatment. The treatment efficiency was 46.3%, and low frequency hearing improvements were better than the high frequency hearing. Including age, process, frequency hearing of impaired before treatment, with or without vertigo isindependent factors influencing its prognosis. Based on the regular treatment,oral and intratympanic injection glucocorticoid therapy are safe and effective for sudden hearing loss,The prognosis and age, course, impaired hearing before curve type, treatment frequency hearing level is closely related, with or without vertigo.

  9. Analysis on heat loss characteristics of a 10 kV HTS power substation

    NASA Astrophysics Data System (ADS)

    Teng, Yuping; Dai, Shaotao; Song, Naihao; Zhang, Jingye; Gao, Zhiyuan; Zhu, Zhiqin; Zhou, Weiwei; Wei, Zhourong; Lin, Liangzhen; Xiao, Liye

    2014-09-01

    A 10 kV High Temperature Superconducting power substation (10 kV HTS substation), supported by Chinese State 863 projects, was developed and has been running to supply power for several factories for more than two years at an industrial park of Baiyin, Gansu province in Northwest China. The system of the 10 kV HTS substation compositions, including a HTS cable, a HTS transformer, a SFCL, and a SMES, are introduced. The SMES works at liquid helium temperature and the other three apparatus operates under liquid nitrogen condition. There are mainly four types of heat losses existing in each HTS apparatus of the 10 kV HTS substation, including AC loss, Joule heat loss, conductive heat, and leak-in heat from cryostat. A small quantity of AC loss still exists due to the harmonic component of the current when it carries DC for HTS apparatus. The principle and basis for analysis of the heat losses are introduced and the total heat loss of each apparatus are calculated or estimated, which agree well with the test result. The analysis and result presented are of importance for the design of the refrigeration system.

  10. Membrane potential depolarization causes alterations in neuron arrangement and connectivity in cocultures

    PubMed Central

    Özkucur, Nurdan; Quinn, Kyle P; Pang, Jin C; Du, Chuang; Georgakoudi, Irene; Miller, Eric; Levin, Michael; Kaplan, David L

    2015-01-01

    Background The disruption of neuron arrangement is associated with several pathologies. In contrast to action potentials, the role of resting potential (Vmem) in regulating connectivity remains unknown. Methods Neuron assemblies were quantified when their Vmem was depolarized using ivermectin (Ivm), a drug that opens chloride channels, for 24 h in cocultures with astrocytes. Cell aggregation was analyzed using automated cluster analysis methods. Neural connectivity was quantified based on the identification of isolated somas in phase-contrast images using image processing. Vmem was measured using voltage-sensitive dyes and whole-cell patch clamping. Immunocytochemistry and Western blotting were used to detect changes in the distribution and production of the proteins. Results Data show that Vmem regulates cortical tissue shape and connectivity. Automated cluster analysis methods revealed that the degree of neural aggregation was significantly increased (0.26 clustering factor vs. 0.21 in controls, P ≤ 0.01). The number of beta-tubulin III positive neural projections was also significantly increased in the neural aggregates in cocultures with Ivm. Hyperpolarized neuron cells formed fewer connections (33% at 24 h, P ≤ 0.05) compared to control cells in 1-day cultures. Glia cell densities increased (33.3%, P ≤ 0.05) under depolarizing conditions. Conclusion Vmem can be a useful tool to probe neuronal cells, disease tissues models, and cortical tissue arrangements. PMID:25722947

  11. Barbiturates induce mitochondrial depolarization and potentiate excitotoxic neuronal death.

    PubMed

    Anderson, Christopher M; Norquist, Becky A; Vesce, Sabino; Nicholls, David G; Soine, William H; Duan, Shumin; Swanson, Raymond A

    2002-11-01

    Barbiturates are widely used as anesthetics, anticonvulsants, and neuroprotective agents. However, barbiturates may also inhibit mitochondrial respiration, and mitochondrial inhibitors are known to potentiate NMDA receptor-mediated neurotoxicity. Here we used rat cortical cultures to examine the effect of barbiturates on neuronal mitochondria and responses to NMDA receptor stimulation. The barbiturates tested, secobarbital, amobarbital, and thiamylal, each potentiated NMDA-induced neuron death at barbiturate concentrations relevant to clinical and experimental use (100-300 microm). By using rhodamine-123 under quenching conditions, barbiturates in this concentration range were shown to depolarize neuronal mitochondria and greatly amplify NMDA-induced mitochondrial depolarization. Barbiturate-induced mitochondrial depolarization was increased by the ATP synthase inhibitor oligomycin, indicating that barbiturates act by inhibiting electron transport sufficiently to cause ATP synthase reversal. Barbiturates similarly amplified the effects of NMDA on cytoplasmic free calcium concentrations. The cell-impermeant barbiturate N-glucoside amobarbital did not influence mitochondrial potential or potentiate NMDA neurotoxicity or calcium responses. However, all of the barbiturates attenuated NMDA-induced calcium elevations and cell death when present at millimolar concentrations. Whole-cell patch-clamp studies showed that these effects may be attributable to actions at the cell membrane, resulting in a block of NMDA-induced current flux at millimolar barbiturate concentrations. Together, these findings reconcile previous reports of opposing effects on barbiturates on NMDA neurotoxicity and show that barbiturate effects on neuronal mitochondria can be functionally significant. Effects of barbiturates on neuronal mitochondria should be considered in experimental and clinical application of these drugs.

  12. Analysis of the environmental impact of insulin infusion sets based on loss of resources with waste.

    PubMed

    Pfützner, Andreas; Musholt, Petra B; Malmgren-Hansen, Bjoern; Nilsson, Nils H; Forst, Thomas

    2011-07-01

    Insulin pump therapy [continuous subcutaneous insulin infusion (CSII)] requires regular change of infusion sets every 2-3 days in order to minimize the risk of skin irritations or other adverse events. This has been discussed to be a potential burden to the environment. The purpose of this analysis was to perform an environmental assessment of insulin pump infusion sets based on loss of resources occurring during incineration of the discarded products and by means of a lifecycle concept used to weight a material in relation to its rareness on earth and its consumption. In addition to five infusion sets (Inset30, InsetII, Comfort, Quick-set, and Cleo), a patch pump (Omnipod) was also included in this analysis. The annual loss in waste of the so called "person reserve" of 3 days of catheter use was compared with daily consumption of a cup of coffee in a disposable paper cup and to a soft drink in an aluminum can. The weight-based loss in resources through waste for the infusion sets (except for Cleo) corresponded to 70-200% of the loss of resources for a coffee cup (Cleo, 320%; Omnipod, 1,821,600%) and to 1-3% of the loss from an aluminum soft drink can (Cleo, 5%; Omnipod, 31,200%). The loss or resources by use of infusion sets used in insulin pump therapy appears to be low and is similar to the burden induced by the uptake of one cup of coffee per day. The loss or resources with regular CSII is considerably lower than the loss or resources induced by patch pumps. © 2011 Diabetes Technology Society.

  13. Uncertainties in Earthquake Loss Analysis: A Case Study From Southern California

    NASA Astrophysics Data System (ADS)

    Mahdyiar, M.; Guin, J.

    2005-12-01

    Probabilistic earthquake hazard and loss analyses play important roles in many areas of risk management, including earthquake related public policy and insurance ratemaking. Rigorous loss estimation for portfolios of properties is difficult since there are various types of uncertainties in all aspects of modeling and analysis. It is the objective of this study to investigate the sensitivity of earthquake loss estimation to uncertainties in regional seismicity, earthquake source parameters, ground motions, and sites' spatial correlation on typical property portfolios in Southern California. Southern California is an attractive region for such a study because it has a large population concentration exposed to significant levels of seismic hazard. During the last decade, there have been several comprehensive studies of most regional faults and seismogenic sources. There have also been detailed studies on regional ground motion attenuations and regional and local site responses to ground motions. This information has been used by engineering seismologists to conduct regional seismic hazard and risk analysis on a routine basis. However, one of the more difficult tasks in such studies is the proper incorporation of uncertainties in the analysis. From the hazard side, there are uncertainties in the magnitudes, rates and mechanisms of the seismic sources and local site conditions and ground motion site amplifications. From the vulnerability side, there are considerable uncertainties in estimating the state of damage of buildings under different earthquake ground motions. From an analytical side, there are challenges in capturing the spatial correlation of ground motions and building damage, and integrating thousands of loss distribution curves with different degrees of correlation. In this paper we propose to address some of these issues by conducting loss analyses of a typical small portfolio in southern California, taking into consideration various source and ground

  14. Kernel component analysis using an epsilon-insensitive robust loss function.

    PubMed

    Alzate, Carlos; Suykens, Johan A K

    2008-09-01

    Kernel principal component analysis (PCA) is a technique to perform feature extraction in a high-dimensional feature space, which is nonlinearly related to the original input space. The kernel PCA formulation corresponds to an eigendecomposition of the kernel matrix: eigenvectors with large eigenvalues correspond to the principal components in the feature space. Starting from the least squares support vector machine (LS-SVM) formulation to kernel PCA, we extend it to a generalized form of kernel component analysis (KCA) with a general underlying loss function made explicit. For classical kernel PCA, the underlying loss function is L(2) . In this generalized form, one can plug in also other loss functions. In the context of robust statistics, it is known that the L(2) loss function is not robust because its influence function is not bounded. Therefore, outliers can skew the solution from the desired one. Another issue with kernel PCA is the lack of sparseness: the principal components are dense expansions in terms of kernel functions. In this paper, we introduce robustness and sparseness into kernel component analysis by using an epsilon-insensitive robust loss function. We propose two different algorithms. The first method solves a set of nonlinear equations with kernel PCA as starting points. The second method uses a simplified iterative weighting procedure that leads to solving a sequence of generalized eigenvalue problems. Simulations with toy and real-life data show improvements in terms of robustness together with a sparse representation.

  15. Coupling-of-modes analysis of STW resonators including loss mechanism.

    PubMed

    Yantchev, Ventsislav M; Strashilov, Vesseline L

    2002-03-01

    Surface transverse wave (STW) resonators exhibit substantial advantages over conventional surface acoustic wave (SAW) resonators. However, their analysis is more involved because of the complicated nature of STW. Many parameters have been studied, but the one that has been difficult to analyze accurately is the quality factor Q, which is of great importance for characterizing the devices. At present, none of the available analytical models is concerned with quantitative loss consideration, and the establishment of reliable design rules is difficult. We present a theoretical study that allows one to conduct coupling-of-modes (COM) STW loss analysis and estimate the resonator Q from material and layout parameters. The COM transmission coefficient chi11 is derived by Floquet analysis. Its imaginary part is obtained by numerically fitting available experimental data for the Q-factor of particular resonators. It is a measure of STW propagation loss that adds to the electrode reflection loss. As the overall loss is extremely sensitive to the choice of parameter values, the full numerical search for optimum design presently discussed can save considerable experimental effort.

  16. Experimental Test of New Technique to Overcome Spin Depolarizing Resonances

    SciTech Connect

    Raymond, R. S.; Chao, A. W.; Krisch, A. D.; Leonova, M. A.; Morozov, V. S.; Sivers, D. W.; Wong, V. K.; Ganshvili, A.; Gebel, R.; Lehrach, A.; Lorentz, B.; Maier, R.; Prasuhn, D.; Stockhorst, H.; Welsch, D.; Hinterberger, F.; Kondratenko, A. M.

    2009-08-04

    We recently tested a new spin resonance crossing technique, Kondratenko Crossing (KC) by sweeping an rf solenoid's frequency through an rf-induced spin resonance with both the KC an traditional Fast Crossing (FC) patterns. Using both rf bunched and unbunched 1.85 GeV/c polarized deuterons stored in COSY, we varied the parameters of both crossing patterns. Compared to FC with the same crossing speed, KC reduced the depolarization by measured factors of 4.7+-0.3 and 19+-{sub 5}{sup 12} for unbunched and bunched beams, respectively. This clearly showed the large potential benefit of Kondratenko Crossing over Fast Crossing.

  17. Neutron depolarization effects in a high-Tc superconductor (abstract)

    NASA Astrophysics Data System (ADS)

    Nunes, A. C.; Pickart, S. J.; Crow, L.; Goyette, R.; McGuire, T. R.; Shinde, S.; Shaw, T. M.

    1988-11-01

    Using the polarized beam small-angle neutron scattering spectrometer at the Rhode Island Nuclear Science Center Reactor, we have observed significant depolarization of a neutron beam by passage through polycrystalline high-Tc superconductors, specifically 123 Y-Ba-Cu-O prepared and characterized at the IBM Watson Research Center. We believe that this technique will prove useful in studying aspects of these materials, such as the penetration depth of shielding currents, the presence and structure of trapped flux vortices, and grain size effects on the supercurrent distribution in polycrystalline samples. The two samples showed sharp transitions at 87 and 89 K, and have been studied at temperatures of 77 K; the second sample has also been studied at 4 K. The transition to the superconducting state was monitored by the shift in resonant frequency of a coil surrounding the sample. No measurable depolarization was observed in either sample at 77 K in both the field-cooled and zero-field-cooled states, using applied fields of 0 (nominal), 54, and 1400 Oe. This negative result may be connected with the fact that the material is still in the reversible region as indicated by susceptibility measurements, but it allows an estimate of the upper bound of possible inhomogeneous internal fields, assuming a distance scale for the superconducting regions. For the 10-μm grain size suggested by photomicrographs, this upper bound for the field turns out to be 1.2 kOe, which seems reasonable. At 4 K a significant depolarization was observed when the sample was cooled in low fields and a field of 1400 Oe was subsequently applied. This result suggests that flux lines are penetrating the sample. Further investigations are being carried out to determine the field and temperature dependence of the depolarization, and attempts will be made to model it quantitatively in terms of possible internal field distributions. We are also searching for possible diffraction effects from ordered vortex

  18. Amphetamine activates calcium channels through dopamine transporter-mediated depolarization.

    PubMed

    Cameron, Krasnodara N; Solis, Ernesto; Ruchala, Iwona; De Felice, Louis J; Eltit, Jose M

    2015-11-01

    Amphetamine (AMPH) and its more potent enantiomer S(+)AMPH are psychostimulants used therapeutically to treat attention deficit hyperactivity disorder and have significant abuse liability. AMPH is a dopamine transporter (DAT) substrate that inhibits dopamine (DA) uptake and is implicated in DA release. Furthermore, AMPH activates ionic currents through DAT that modify cell excitability presumably by modulating voltage-gated channel activity. Indeed, several studies suggest that monoamine transporter-induced depolarization opens voltage-gated Ca(2+) channels (CaV), which would constitute an additional AMPH mechanism of action. In this study we co-express human DAT (hDAT) with Ca(2+) channels that have decreasing sensitivity to membrane depolarization (CaV1.3, CaV1.2 or CaV2.2). Although S(+)AMPH is more potent than DA in transport-competition assays and inward-current generation, at saturating concentrations both substrates indirectly activate voltage-gated L-type Ca(2+) channels (CaV1.3 and CaV1.2) but not the N-type Ca(2+) channel (CaV2.2). Furthermore, the potency to achieve hDAT-CaV electrical coupling is dominated by the substrate affinity on hDAT, with negligible influence of L-type channel voltage sensitivity. In contrast, the maximal coupling-strength (defined as Ca(2+) signal change per unit hDAT current) is influenced by CaV voltage sensitivity, which is greater in CaV1.3- than in CaV1.2-expressing cells. Moreover, relative to DA, S(+)AMPH showed greater coupling-strength at concentrations that induced relatively small hDAT-mediated currents. Therefore S(+)AMPH is not only more potent than DA at inducing hDAT-mediated L-type Ca(2+) channel currents but is a better depolarizing agent since it produces tighter electrical coupling between hDAT-mediated depolarization and L-type Ca(2+) channel activation.

  19. Integral decomposition and polarization properties of depolarizing Mueller matrices.

    PubMed

    Ossikovski, Razvigor; Arteaga, Oriol

    2015-03-15

    We show that, by suitably defining the integral decomposition of a depolarizing Mueller matrix, it becomes possible to fully interpret the polarization response of the medium or structure under study in terms of mean values and variances-covariances of a set of six integral polarization properties. The latter appear as natural counterparts of the elementary (differential) polarization properties stemming from the differential decomposition of the Mueller matrix. However, unlike the differential decomposition, the integral one is always mathematically and physically realizable and is furthermore unambiguously defined inasmuch as a nondepolarizing estimate of the initial Mueller matrix is secured. The theoretical results are illustrated on an experimental example.

  20. GABA actions in hippocampal area CA3 during postnatal development: differential shift from depolarizing to hyperpolarizing in somatic and dendritic compartments.

    PubMed

    Romo-Parra, Héctor; Treviño, Mario; Heinemann, Uwe; Gutiérrez, Rafael

    2008-03-01

    Gamma-aminobutyric acid type A receptor (GABA(A)-R) activation leads to depolarization of pyramidal cells during the first postnatal week and produces hyperpolarization from the second week. However, immunohistochemical evidence has suggested that during the second and third postnatal weeks the NKCC1 cotransporter relocates from the soma to the dendrites of CA3 pyramidal cells. We hypothesized that this leads to depolarizing responses in apical dendrites. Here we show that the activation of GABA(A)-R in the distal dendrites of CA3 pyramidal cells at P15 by restricted application of muscimol or synaptic activation by stimulation of interneurons in stratum radiatum (SR) causes depolarizing postsynaptic potentials (PSPs), which are blocked by NKCC1 cotransporter antagonists. By contrast, activation of proximal GABA(A)-R by muscimol application or by stimulation of interneurons in s. oriens (SO) leads to hyperpolarizing PSPs. Activation of the dentate gyrus (DG) in the presence of glutamatergic blockers evokes hyperpolarizing responses during the second postnatal week; however, the reversal potential of the DG-evoked inhibitory (I)PSPs is more depolarized than that of IPSPs evoked by activation of SO interneurons. Despite the shift of GABA action from depolarizing to hyperpolarizing, DG-evoked field potentials (f-PSPs) recorded in s. lucidum/radiatum (SL/R) do not change in polarity until the third week. Current source density analysis yielded results consistent with depolarizing actions of GABA in the dendritic compartment. Our data suggest that GABAergic input to apical dendrites of pyramidal cells of CA3 evokes depolarizing PSPs long after synaptic inhibition has become hyperpolarizing in the somata, in the axon initial segments and in basal dendrites.

  1. Distinct characteristics of Ca(2+)-induced depolarization of isolated brain and liver mitochondria.

    PubMed

    Vergun, Olga; Reynolds, Ian J

    2005-09-05

    Ca(2+)-induced mitochondrial depolarization was studied in single isolated rat brain and liver mitochondria. Digital imaging techniques and rhodamine 123 were used for mitochondrial membrane potential measurements. Low Ca(2+) concentrations (about 30--100 nM) initiated oscillations of the membrane potential followed by complete depolarization in brain mitochondria. In contrast, liver mitochondria were less sensitive to Ca(2+); 20 microm Ca(2+) was required to depolarize liver mitochondria. Ca(2+) did not initiate oscillatory depolarizations in liver mitochondria, where each individual mitochondrion depolarized abruptly and irreversibly. Adenine nucleotides dramatically reduced the oscillatory depolarization in brain mitochondria and delayed the onset of the depolarization in liver mitochondria. In both type of mitochondria, the stabilizing effect of adenine nucleotides completely abolished by an inhibition of adenine nucleotide translocator function with carboxyatractyloside, but was not sensitive to bongkrekic acid. Inhibitors of mitochondrial permeability transition cyclosporine A and bongkrekic acid also delayed Ca(2+)-depolarization. We hypothesize that the oscillatory depolarization in brain mitochondria is associated with the transient conformational change of the adenine nucleotide translocator from a specific transporter to a non-specific pore, whereas the non-oscillatory depolarization in liver mitochondria is caused by the irreversible opening of the pore.

  2. Forward-angle elastic p-->p spin-depolarization and -rotation parameters at 0.8 GeV

    NASA Astrophysics Data System (ADS)

    Barlett, M. L.; Hoffmann, G. W.; McGill, J. A.; Fergerson, R. W.; Milner, E. C.; Marshall, J. A.; Amann, J. F.; Bonner, B. E.; McClelland, J. B.

    1984-07-01

    800 MeV elastic p-->+p spin-depolarization and -rotation parameters DNN, DSS, DLL, DSL, and DLS have been measured for the center-of-momentum angular range 4.8°-23.8° (0.26 fm-1<=q<=1.28 fm-1). Statistical uncertainties are ~=+/-0.01-0.02 and total systematic uncertainty is <=+/-0.035. The data are in overall agreement with predictions from global phase shift analysis.

  3. Low reproductive rate predicts species sensitivity to habitat loss: a meta-analysis of wetland vertebrates.

    PubMed

    Quesnelle, Pauline E; Lindsay, Kathryn E; Fahrig, Lenore

    2014-01-01

    We tested the hypotheses that species with greater mobility and/or higher reproductive rates are less sensitive to habitat loss than species with lower mobility and/or reproductive rates by conducting a meta-analysis of wetland vertebrate responses to wetland habitat loss. We combined data from 90 studies conducted worldwide that quantified the relationship between wetland amount in a landscape and population abundance of at least one wetland species to determine if mobility (indexed as home range size and body length) and annual reproductive rate influence species responses to wetland loss. When analyzed across all taxa, animals with higher reproductive rates were less sensitive to wetland loss. Surprisingly, we did not find an effect of mobility on response to wetland loss. Overall, wetland mammals and birds were more sensitive to wetland loss than were reptiles and amphibians. Our results suggest that dispersal between habitat patches is less important than species' reproductive rates for population persistence in fragmented landscapes. This implies that immigration and colonization rate is most strongly related to reproduction, which determines the total number of potential colonists.

  4. Low Reproductive Rate Predicts Species Sensitivity to Habitat Loss: A Meta-Analysis of Wetland Vertebrates

    PubMed Central

    Quesnelle, Pauline E.; Lindsay, Kathryn E.; Fahrig, Lenore

    2014-01-01

    We tested the hypotheses that species with greater mobility and/or higher reproductive rates are less sensitive to habitat loss than species with lower mobility and/or reproductive rates by conducting a meta-analysis of wetland vertebrate responses to wetland habitat loss. We combined data from 90 studies conducted worldwide that quantified the relationship between wetland amount in a landscape and population abundance of at least one wetland species to determine if mobility (indexed as home range size and body length) and annual reproductive rate influence species responses to wetland loss. When analyzed across all taxa, animals with higher reproductive rates were less sensitive to wetland loss. Surprisingly, we did not find an effect of mobility on response to wetland loss. Overall, wetland mammals and birds were more sensitive to wetland loss than were reptiles and amphibians. Our results suggest that dispersal between habitat patches is less important than species’ reproductive rates for population persistence in fragmented landscapes. This implies that immigration and colonization rate is most strongly related to reproduction, which determines the total number of potential colonists. PMID:24651675

  5. A meta-analysis of risk of pregnancy loss and caffeine and coffee consumption during pregnancy.

    PubMed

    Li, Ji; Zhao, Hong; Song, Ju-Min; Zhang, Jing; Tang, Yin-Lan; Xin, Chang-Mao

    2015-08-01

    Previous reports of the relationship between pregnancy loss and caffeine/coffee consumption have been inconsistent. To evaluate the association between pregnancy loss and caffeine and coffee consumption. PubMed was searched for reports published before September 2014, with the keywords "caffeine," "coffee," "beverage," "miscarriage," "spontaneous abortion," and "fetal loss." Case-control and cohort studies were included when they had been reported in English, the exposure of interest was caffeine/coffee consumption during pregnancy, the outcome of interest was spontaneous abortion or fetal death, and multivariate-adjusted odds ratios (ORs) or risk ratios were provided or could be calculated. Data were extracted and combined ORs calculated. Overall, 26 studies were included (20 of caffeine and eight of coffee). After adjustment for heterogeneity, caffeine consumption was associated with an increased risk of pregnancy loss (OR 1.32, 95% confidence interval [CI] 1.24-1.40), as was coffee consumption (OR 1.11, 95% CI 1.02-1.21). A dose-response analysis suggested that risk of pregnancy loss rose by 19% for every increase in caffeine intake of 150 mg/day and by 8% for every increase in coffee intake of two cups per day. Consumption of caffeine and coffee during pregnancy seems to increase the risk of pregnancy loss. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  6. Analysis of several factors of variation of gestation loss in breeding mares.

    PubMed

    Langlois, B; Blouin, C; Chaffaux, S

    2012-12-01

    The files for ultrasound diagnosis of gestating mares belonging to the French equine herd recorded for 3 consecutive years were joined with the files for foal birth of these same mares, allowing the statistical analysis of factors of pregnancy loss. For 28 872 positive diagnoses of gestation, 2898 losses were recorded, that is, a global rate of gestation interruption of 9.12%. The etiology of these interruptions is mainly extrinsic: the year and month of insemination, as well as region for climatic reasons. The intrinsic causes that are implicated are breed of the father (heavy breeds except the hypermetric ones lose fewer pregnancies than warm-blooded breeds), age of the mother (losses are lower in mares of 7 to 10 years of age) and status (mares with foals have fewer pregnancy losses than mares not having foaled the previous year), as well as fetuses with consanguinity (when this increases, the pregnancy losses increase as well). However, the additive genetic effect is extremely low; it corresponds to heritability below 5% and few effects of the environment, common to the offspring of the same mare, were identified. This therefore gives little hope of being able to select against the 'gestation loss' trait.

  7. Statistical Analysis of the Human Strangulation Experiments: Comparison to +GZ-Induced Loss of Consciousness.

    DTIC Science & Technology

    1992-02-18

    CONSCIOUSNESS Estrella M. Forster UJ.S. and James E. Whinnery Ph.D., M.D. Air Vehicle and Crew Systems Technology Department (Code 6023) NAVAL AIR WARFARE CENTER...STATISTICAL ANALYSIS OF THE HUMAN STRANGULATION EXPERIMENTS: COMPARISON TO +Gz-INDUCED LOSS OF CONSCIOUSNESS 6. AUTHOR(S) Estrella M. Forster B.S

  8. A Comparative Analysis of USAF Fixed-Wing Aircraft Losses in Southeast Asia Combat

    DTIC Science & Technology

    1977-12-01

    corporation , or conveying any rights or permission to manufacture, use, or sell any patented invention that may in any way be related thereto. This...unclassltoieo) REFERENCES I P. C. Hewett, et al, Analysis f USAF Fixed-Wing Aircraft Losses, Aircrew Casualties and F-105 Da.1)es in SEASIA Comnat (U), AFFDL-R

  9. Intensity distribution analysis of cathodoluminescence using the energy loss distribution of electrons.

    PubMed

    Fukuta, Masahiro; Inami, Wataru; Ono, Atsushi; Kawata, Yoshimasa

    2016-01-01

    We present an intensity distribution analysis of cathodoluminescence (CL) excited with a focused electron beam in a luminescent thin film. The energy loss distribution is applied to the developed analysis method in order to determine the arrangement of the dipole locations along the path of the electron traveling in the film. Propagating light emitted from each dipole is analyzed with the finite-difference time-domain (FDTD) method. CL distribution near the film surface is evaluated as a nanometric light source. It is found that a light source with 30 nm widths is generated in the film by the focused electron beam. We also discuss the accuracy of the developed analysis method by comparison with experimental results. The analysis results are brought into good agreement with the experimental results by introducing the energy loss distribution.

  10. Spreading Depression, Spreading Depolarizations, and the Cerebral Vasculature

    PubMed Central

    Ayata, Cenk; Lauritzen, Martin

    2015-01-01

    Spreading depression (SD) is a transient wave of near-complete neuronal and glial depolarization associated with massive transmembrane ionic and water shifts. It is evolutionarily conserved in the central nervous systems of a wide variety of species from locust to human. The depolarization spreads slowly at a rate of only millimeters per minute by way of grey matter contiguity, irrespective of functional or vascular divisions, and lasts up to a minute in otherwise normal tissue. As such, SD is a radically different breed of electrophysiological activity compared with everyday neural activity, such as action potentials and synaptic transmission. Seventy years after its discovery by Leão, the mechanisms of SD and its profound metabolic and hemodynamic effects are still debated. What we did learn of consequence, however, is that SD plays a central role in the pathophysiology of a number of diseases including migraine, ischemic stroke, intracranial hemorrhage, and traumatic brain injury. An intriguing overlap among them is that they are all neurovascular disorders. Therefore, the interplay between neurons and vascular elements is critical for our understanding of the impact of this homeostatic breakdown in patients. The challenges of translating experimental data into human pathophysiology notwithstanding, this review provides a detailed account of bidirectional interactions between brain parenchyma and the cerebral vasculature during SD and puts this in the context of neurovascular diseases. PMID:26133935

  11. Spreading Depression, Spreading Depolarizations, and the Cerebral Vasculature.

    PubMed

    Ayata, Cenk; Lauritzen, Martin

    2015-07-01

    Spreading depression (SD) is a transient wave of near-complete neuronal and glial depolarization associated with massive transmembrane ionic and water shifts. It is evolutionarily conserved in the central nervous systems of a wide variety of species from locust to human. The depolarization spreads slowly at a rate of only millimeters per minute by way of grey matter contiguity, irrespective of functional or vascular divisions, and lasts up to a minute in otherwise normal tissue. As such, SD is a radically different breed of electrophysiological activity compared with everyday neural activity, such as action potentials and synaptic transmission. Seventy years after its discovery by Leão, the mechanisms of SD and its profound metabolic and hemodynamic effects are still debated. What we did learn of consequence, however, is that SD plays a central role in the pathophysiology of a number of diseases including migraine, ischemic stroke, intracranial hemorrhage, and traumatic brain injury. An intriguing overlap among them is that they are all neurovascular disorders. Therefore, the interplay between neurons and vascular elements is critical for our understanding of the impact of this homeostatic breakdown in patients. The challenges of translating experimental data into human pathophysiology notwithstanding, this review provides a detailed account of bidirectional interactions between brain parenchyma and the cerebral vasculature during SD and puts this in the context of neurovascular diseases.

  12. Depolarizing Actions of Hydrogen Sulfide on Hypothalamic Paraventricular Nucleus Neurons

    PubMed Central

    Khademullah, C. Sahara; Ferguson, Alastair V.

    2013-01-01

    Hydrogen sulfide (H2S) is a novel neurotransmitter that has been shown to influence cardiovascular functions as well and corticotrophin hormone (CRH) secretion. Since the paraventricular nucleus of the hypothalamus (PVN) is a central relay center for autonomic and endocrine functions, we sought to investigate the effects of H2S on the neuronal population of the PVN. Whole cell current clamp recordings were acquired from the PVN neurons and sodium hydrosulfide hydrate (NaHS) was bath applied at various concentrations (0.1, 1, 10, and 50 mM). NaHS (1, 10, and 50 mM) elicited a concentration-response relationship from the majority of recorded neurons, with almost exclusively depolarizing effects following administration. Cells responded and recovered from NaHS administration quickly and the effects were repeatable. Input differences from baseline and during the NaHS-induced depolarization uncovered a biphasic response, implicating both a potassium and non-selective cation conductance. The results from the neuronal population of the PVN shed light on the possible physiological role that H2S has in autonomic and endocrine function. PMID:23691233

  13. Depolarization Lidar Determination Of Cloud-Base Microphysical Properties

    NASA Astrophysics Data System (ADS)

    Donovan, D. P.; Klein Baltink, H.; Henzing, J. S.; de Roode, S.; Siebesma, A. P.

    2016-06-01

    The links between multiple-scattering induced depolarization and cloud microphysical properties (e.g. cloud particle number density, effective radius, water content) have long been recognised. Previous efforts to use depolarization information in a quantitative manner to retrieve cloud microphysical cloud properties have also been undertaken but with limited scope and, arguably, success. In this work we present a retrieval procedure applicable to liquid stratus clouds with (quasi-)linear LWC profiles and (quasi-)constant number density profiles in the cloud-base region. This set of assumptions allows us to employ a fast and robust inversion procedure based on a lookup-table approach applied to extensive lidar Monte-Carlo multiple-scattering calculations. An example validation case is presented where the results of the inversion procedure are compared with simultaneous cloud radar observations. In non-drizzling conditions it was found, in general, that the lidar- only inversion results can be used to predict the radar reflectivity within the radar calibration uncertainty (2-3 dBZ). Results of a comparison between ground-based aerosol number concentration and lidar-derived cloud base number considerations are also presented. The observed relationship between the two quantities is seen to be consistent with the results of previous studies based on aircraft-based in situ measurements.

  14. Subarachnoid Hemorrhage, Spreading Depolarizations and Impaired Neurovascular Coupling

    PubMed Central

    Koide, Masayo; Sukhotinsky, Inna; Ayata, Cenk; Wellman, George C.

    2013-01-01

    Aneurysmal subarachnoid hemorrhage (SAH) has devastating consequences on brain function including profound effects on communication between neurons and the vasculature leading to cerebral ischemia. Physiologically, neurovascular coupling represents a focal increase in cerebral blood flow to meet increased metabolic demand of neurons within active regions of the brain. Neurovascular coupling is an ongoing process involving coordinated activity of the neurovascular unit—neurons, astrocytes, and parenchymal arterioles. Neuronal activity can also influence cerebral blood flow on a larger scale. Spreading depolarizations (SD) are self-propagating waves of neuronal depolarization and are observed during migraine, traumatic brain injury, and stroke. Typically, SD is associated with increased cerebral blood flow. Emerging evidence indicates that SAH causes inversion of neurovascular communication on both the local and global level. In contrast to other events causing SD, SAH-induced SD decreases rather than increases cerebral blood flow. Further, at the level of the neurovascular unit, SAH causes an inversion of neurovascular coupling from vasodilation to vasoconstriction. Global ischemia can also adversely affect the neurovascular response. Here, we summarize current knowledge regarding the impact of SAH and global ischemia on neurovascular communication. A mechanistic understanding of these events should provide novel strategies to treat these neurovascular disorders. PMID:23577279

  15. Clinical analysis of implant losses in oral tumor and defect patients.

    PubMed

    Kovács, A F

    2000-10-01

    In the period between 1990 and 1996, 279 endosteal dental Bone-Lock implants were placed in 79 patients. Of them 63 have been treated with ablative tumor and reconstructive surgery in the oral cavity, the rest presented with maxillo-mandibular defects of different origin. The circumstances of implant loss were noted down for descriptive analysis concerning age, sex, topography, implant dimensions, loading, time in place and type of superstructure. Failure analysis was done concerning the implants and the patients. Five causes for implant loss could be detected: lacking primary osseointegration, acute inflammation, bone loss, biomechanical overloading and tumor recurrence. No predictive factors for implant loss and no age influence on implant loss could be detected, no specific local implant site and no specific superstructure had an identifiable higher risk. Survival rate of all placed implants in oral tumor and defect patients was 83.5% after 6 years observation. Male tumor patients were found to have a higher risk to lose implants than females. Free iliac bone grafts impaired osseointegration of implants. The mandible offered a better prognosis for the implants than the maxilla. Shorter and thinner implants had a higher risk of being lost. A quarter of all patients (26.3%) had to face implant loss. Clustering of implant loss in several patients was caused by free iliac bone grafting and by prosthetic faults. Chemotherapy had no negative influence on implant survival. Most implants were lost early (76%) before fabrication of the prosthesis. After restoration there was a nearly 100% probability of function. It is concluded that implant treatment can be equally effective for tumor and defect patients as it is known for healthy subjects.

  16. ANALYSIS OF DISTRIBUTION FEEDER LOSSES DUE TO ADDITION OF DISTRIBUTED PHOTOVOLTAIC GENERATORS

    SciTech Connect

    Tuffner, Francis K.; Singh, Ruchi

    2011-08-09

    Distributed generators (DG) are small scale power supplying sources owned by customers or utilities and scattered throughout the power system distribution network. Distributed generation can be both renewable and non-renewable. Addition of distributed generation is primarily to increase feeder capacity and to provide peak load reduction. However, this addition comes with several impacts on the distribution feeder. Several studies have shown that addition of DG leads to reduction of feeder loss. However, most of these studies have considered lumped load and distributed load models to analyze the effects on system losses, where the dynamic variation of load due to seasonal changes is ignored. It is very important for utilities to minimize the losses under all scenarios to decrease revenue losses, promote efficient asset utilization, and therefore, increase feeder capacity. This paper will investigate an IEEE 13-node feeder populated with photovoltaic generators on detailed residential houses with water heater, Heating Ventilation and Air conditioning (HVAC) units, lights, and other plug and convenience loads. An analysis of losses for different power system components, such as transformers, underground and overhead lines, and triplex lines, will be performed. The analysis will utilize different seasons and different solar penetration levels (15%, 30%).

  17. What Is the Hidden Depolarization Mechanism in Low-luminosity AGNs?

    NASA Astrophysics Data System (ADS)

    Bower, Geoffrey C.; Dexter, Jason; Markoff, Sera; Rao, Ramprasad; Plambeck, R. L.

    2017-07-01

    Millimeter-wavelength polarimetry of accreting black hole systems can provide a tomographic probe of the accretion flow on a wide range of linear scales. We searched for linear polarization in two low-luminosity active galactic nuclei (LLAGNs), M81 and M84, using the Combined Array for Millimeter Astronomy and the Submillimeter Array. We find upper limits of ˜1%-2% averaging over the full bandwidth and with a rotation measure (RM) synthesis technique. These low polarization fractions, along with similarly low values for LLAGNs M87 and 3C 84, suggest that LLAGNs have qualitatively different polarization properties than radio-loud sources and Sgr A*. If the sources are intrinsically polarized and then depolarized by Faraday rotation, then we place lower limits on the RM of a few times {10}7 {rad} {{{m}}}-2 for the full bandwidth case and ˜ {10}9 {rad} {{{m}}}-2 for the RM synthesis analysis. These limits are inconsistent with or marginally consistent with expected accretion flow properties. Alternatively, the sources may be depolarized by cold electrons within a few Schwarzschild radii from the black hole, as suggested by numerical models.

  18. Exogenously Applied 24-Epibrassinolide (EBL) Ameliorates Detrimental Effects of Salinity by Reducing K+ Efflux via Depolarization-Activated K+ Channels.

    PubMed

    Azhar, Nazila; Su, Nana; Shabala, Lana; Shabala, Sergey

    2017-03-02

    This study has investigated mechanisms conferring beneficial effects of exogenous application of 24-epibrassinolides (EBL) on plant growth and performance under saline conditions. Barley seedlings treated with 0.25 mg l-1 EBL showed significant improvements in root hair length, shoot length, shoot fresh weight and relative water content when grown in the presence of 150 mM NaCl in the growth medium. In addition, EBL treatment significantly decreased the Na+ content in both shoots (by approximately 50%) and roots. Electrophysiological experiments revealed that pre-treatment with EBL for 1 and 24 h suppressed or completely prevented the NaCl-induced K+ leak in the elongation zone of barley roots, but did not affect root sensitivity to oxidative stress. Further experiments using Arabidopsis loss-of-function gork1-1 (lacking functional depolarization-activated outward-rectifying K+ channels in the root epidermal cells) and akt1 (lacking inward-rectifying K+ uptake channel) mutants showed that NaCl-induced K+ loss in the elongation zone of roots was reduced by EBL pre-treatment 50- to 100-fold in wild-type Col-0 and akt1, but only 10-fold in the gork1-1 mutant. At the same time, EBL treatment shifted vanadate-sensitive H+ flux towards net efflux. Taken together, these data indicate that exogenous application of EBL effectively improves plant salinity tolerance by prevention of K+ loss via regulating depolarization-activated K+ channels.

  19. The Development of Loss of Flow Analysis Method for OPR1000 Using RETRAN

    SciTech Connect

    Dong Hyuk Lee; Yo-Han Kim; Chang-Kyung Sung

    2006-07-01

    A new loss of flow transient analysis method for OPR1000 (Optimized Power Reactor 1000, previously called KSNP: Korean Standard Nuclear Power Plant) based on RETRAN code were developed. The reference plant for the analysis is Ulchin Unit 3 and the transient analyzed is 4 pump coast-down. The current analysis for loss of RCS flow transient of OPR1000 uses COAST and CESEC codes. The new method uses RETRAN code to replace COAST and CESEC codes. Since the ability of RETRAN to replace CESEC has been studied in other non-LOCA transients, this paper will focus on COAST code and RCP coast-down flow rates. The results from simplified RETRAN nodalization corresponding to COAST show good agreement with RCS flow results from COAST code. The results are also compared with RETRAN base-deck for safety analysis which is more complex and show similar trends. Therefore, previous analysis method for loss of flow of OPR1000 using COAST code can be replaced with the new analysis method based on RETRAN. (authors)

  20. Cluster analysis of the national weight control registry to identify distinct subgroups maintaining successful weight loss.

    PubMed

    Ogden, Lorraine G; Stroebele, Nanette; Wyatt, Holly R; Catenacci, Victoria A; Peters, John C; Stuht, Jennifer; Wing, Rena R; Hill, James O

    2012-10-01

    The National Weight Control Registry (NWCR) is the largest ongoing study of individuals successful at maintaining weight loss; the registry enrolls individuals maintaining a weight loss of at least 13.6 kg (30 lb) for a minimum of 1 year. The current report uses multivariate latent class cluster analysis to identify unique clusters of individuals within the NWCR that have distinct experiences, strategies, and attitudes with respect to weight loss and weight loss maintenance. The cluster analysis considers weight and health history, weight control behaviors and strategies, effort and satisfaction with maintaining weight, and psychological and demographic characteristics. The analysis includes 2,228 participants enrolled between 1998 and 2002. Cluster 1 (50.5%) represents a weight-stable, healthy, exercise conscious group who are very satisfied with their current weight. Cluster 2 (26.9%) has continuously struggled with weight since childhood; they rely on the greatest number of resources and strategies to lose and maintain weight, and report higher levels of stress and depression. Cluster 3 (12.7%) represents a group successful at weight reduction on the first attempt; they were least likely to be overweight as children, are maintaining the longest duration of weight loss, and report the least difficulty maintaining weight. Cluster 4 (9.9%) represents a group less likely to use exercise to control weight; they tend to be older, eat fewer meals, and report more health problems. Further exploration of the unique characteristics of these clusters could be useful for tailoring future weight loss and weight maintenance programs to the specific characteristics of an individual.

  1. Model parameter uncertainty analysis for an annual field-scale P loss model

    NASA Astrophysics Data System (ADS)

    Bolster, Carl H.; Vadas, Peter A.; Boykin, Debbie

    2016-08-01

    Phosphorous (P) fate and transport models are important tools for developing and evaluating conservation practices aimed at reducing P losses from agricultural fields. Because all models are simplifications of complex systems, there will exist an inherent amount of uncertainty associated with their predictions. It is therefore important that efforts be directed at identifying, quantifying, and communicating the different sources of model uncertainties. In this study, we conducted an uncertainty analysis with the Annual P Loss Estimator (APLE) model. Our analysis included calculating parameter uncertainties and confidence and prediction intervals for five internal regression equations in APLE. We also estimated uncertainties of the model input variables based on values reported in the literature. We then predicted P loss for a suite of fields under different management and climatic conditions while accounting for uncertainties in the model parameters and inputs and compared the relative contributions of these two sources of uncertainty to the overall uncertainty associated with predictions of P loss. Both the overall magnitude of the prediction uncertainties and the relative contributions of the two sources of uncertainty varied depending on management practices and field characteristics. This was due to differences in the number of model input variables and the uncertainties in the regression equations associated with each P loss pathway. Inspection of the uncertainties in the five regression equations brought attention to a previously unrecognized limitation with the equation used to partition surface-applied fertilizer P between leaching and runoff losses. As a result, an alternate equation was identified that provided similar predictions with much less uncertainty. Our results demonstrate how a thorough uncertainty and model residual analysis can be used to identify limitations with a model. Such insight can then be used to guide future data collection and model

  2. Body weight loss reverts obesity-associated hypogonadotropic hypogonadism: a systematic review and meta-analysis.

    PubMed

    Corona, Giovanni; Rastrelli, Giulia; Monami, Matteo; Saad, Farid; Luconi, Michaela; Lucchese, Marcello; Facchiano, Enrico; Sforza, Alessandra; Forti, Gianni; Mannucci, Edoardo; Maggi, Mario

    2013-06-01

    Few randomized clinical studies have evaluated the impact of diet and physical activity on testosterone levels in obese men with conflicting results. Conversely, studies on bariatric surgery in men generally have shown an increase in testosterone levels. The aim of this study is to perform a systematic review and meta-analysis of available trials on the effect of body weight loss on sex hormones levels. Meta-analysis. An extensive Medline search was performed including the following words: 'testosterone', 'diet', 'weight loss', 'bariatric surgery', and 'males'. The search was restricted to data from January 1, 1969 up to August 31, 2012. Out of 266 retrieved articles, 24 were included in the study. Of the latter, 22 evaluated the effect of diet or bariatric surgery, whereas two compared diet and bariatric surgery. Overall, both a low-calorie diet and bariatric surgery are associated with a significant (P<0.0001) increase in plasma sex hormone-binding globulin-bound and -unbound testosterone levels (total testosterone (TT)), with bariatric surgery being more effective in comparison with the low-calorie diet (TT increase: 8.73 (6.51-10.95) vs 2.87 (1.68-4.07) for bariatric surgery and the low-calorie diet, respectively; both P<0.0001 vs baseline). Androgen rise is greater in those patients who lose more weight as well as in younger, non-diabetic subjects with a greater degree of obesity. Body weight loss is also associated with a decrease in estradiol and an increase in gonadotropins levels. Multiple regression analysis shows that the degree of body weight loss is the best determinant of TT rise (B=2.50±0.98, P=0.029). These data show that weight loss is associated with an increase in both bound and unbound testosterone levels. The normalization of sex hormones induced by body weight loss is a possible mechanism contributing to the beneficial effects of surgery in morbid obesity.

  3. The impact of perinatal loss in maternity units: A psycholinguistic analysis of health professionals' reactions.

    PubMed

    Gandino, Gabriella; Di Fini, Giulia; Bernaudo, Antonella; Paltrinieri, Marcello; Castiglioni, Marco; Veglia, Fabio

    2017-08-01

    Perinatal loss has a strong emotional impact on health professionals working in maternity units. We aimed to study the impact of this experience on health professionals' language. We analyzed the answers of 162 health professionals (physicians and non-medical staff) who described their reactions to perinatal loss. A linguistic analysis was performed using the Linguistic Inquiry and Word Count software. Associations between language and burnout were studied. Words typical of a psychological shock reaction were used more by non-medical staff than by physicians. Participants who used pronouns, optimistic words, future tense verbs, and cognitive words registered lower levels of burnout. Clinical implications of the results are discussed.

  4. Analysis of intrinsic coupling loss in multi-step index optical fibres.

    PubMed

    Aldabaldetreku, Gotzon; Durana, Gaizka; Zubia, Joseba; Arrue, Jon; Jiménez, Felipe; Mateo, Javier

    2005-05-02

    The main goal of the present paper is to provide a comprehensive analysis of the intrinsic coupling loss for multi-step index (MSI) fibres and compare it with those obtained for step- and graded-index fibres. We investigate the effects of tolerances to each waveguide parameter typical in standard manufacturing processes by carrying out several simulations using the ray-tracing method. The results obtained will serve us to identify the most critical waveguide variations to which fibre manufactures will have to pay closer attention to achieve lower coupling losses.

  5. Meta-analysis to obtain a scale of psychological reaction after perinatal loss: focus on miscarriage.

    PubMed

    Adolfsson, Annsofie

    2011-01-01

    Pregnancy has different meanings to different women depending upon their circumstances. A number of qualitative studies have described the experience of miscarriage by women who had desired to carry their pregnancy to full term. The aim of this meta-analysis was to identify a scale of psychological reaction to miscarriage. Meta-analysis is a quantitative approach for reviewing articles from scientific journals through statistical analysis of findings from individual studies. In this review, a meta-analytic method was used to identify and analyze psychological reactions in women who have suffered a miscarriage. Different reactions to stress associated with the period following miscarriage were identified. The depression reaction had the highest average, weighted, unbiased estimate of effect (d(+) = 0.99) and was frequently associated with the experience of perinatal loss. Psychiatric morbidity was found after miscarriage in 27% of cases by a diagnostic interview ten days after miscarriage. The grief reaction had a medium d(+) of 0.56 in the studies included. However, grief after miscarriage differed from other types of grief after perinatal loss because the parents had no focus for their grief. The guilt is greater after miscarriage than after other types of perinatal loss. Measurement of the stress reaction and anxiety reaction seems to be difficult in the included studies, as evidenced by a low d(+) (0.17 and 0.16, respectively). It has been recommended that grief after perinatal loss be measured by an adapted instrument called the Perinatal Grief Scale Short Version.

  6. A depolarization and attenuation experiment using the CTS satellite. Volume 1: Experiment description

    NASA Technical Reports Server (NTRS)

    Bostian, C. W.; Holt, S. B., Jr.; Kauffman, S. R.; Manus, E. A.; Marshall, R. E.; Stutzman, W. L.; Wiley, P. H.

    1976-01-01

    An experiment for measuring precipitation attenuation and depolarization on the Communications Technology Satellite (CTS) 11.7 GHz downlink is described. Attenuation and depolarization of the signal received from the spacecraft is monitored on a 24 hour basis. Data is correlated with ground weather conditions. Theoretical models for millimeter wave propagation through rain are refined for maximum agreement with observed data. Techniques are developed for predicting and mimimizing the effects of rain scatter and depolarization on future satellite communication systems.

  7. Results of the VPI&SU Comstar experiment. [depolarization and attenuation due to rain

    NASA Technical Reports Server (NTRS)

    Andrews, J. H.; Ozbay, C.; Pratt, T.; Bostian, C. W.; Manus, E. A.; Gaines, J. M.; Marshall, R. E.; Stutzman, W. L.; Wiley, P. H.

    1982-01-01

    This paper summarizes annual and cumulative attenuation data, depolarization data, and associated local rain rate distributions obtained with the Comstar family of 19.04- and 28.56-GHz satellite beacons during the years 1977-1981. It discusses the relationships between attenuation and rain rate and between attenuation and depolarization, compares measured data on the joint distribution of attenuation and depolarization, and examines the limitations that propagation effects will impose on future 20/30-GHz satellite communications systems.

  8. Precision measurement system and analysis of low core signal loss in DCF couplers

    NASA Astrophysics Data System (ADS)

    Yan, P.; Wang, X. J.; Fu, Ch; Li, D.; Sun, J. Y.; Gong, M. L.; Xiao, Q. R.

    2016-07-01

    In order to achieve higher output power of double cladding fiber lasers, low signal loss has become a focus in researches on optical technology, especially double-clad fiber (DCF) couplers. According to the analysis, DCF couplers with low core signal loss (less than 1%) are produced. To obtain higher precision, we use the first-proposed method for core signal transfer efficiency measurement based on the fiber propagation field image processing. To the best of our knowledge, we report, for the first time, the results of the core signal loss less than 1% in DCF coupler measured by our measurement with high stability and relative precision. The measurement values can assess the quality of DCF couplers and be used as a signal to suggest the improvement on the processing technology of our self-made DCF couplers.

  9. The familial influence of loss and trauma on refugee mental health: a multilevel path analysis.

    PubMed

    Nickerson, Angela; Bryant, Richard A; Brooks, Robert; Steel, Zachary; Silove, Derrick; Chen, Jack

    2011-02-01

    Although the impact of human rights violations on the mental health of refugees has been well documented, little is known about these effects at a family level. In this study the authors examined the relationships among loss, trauma, and mental health at the individual and family levels in resettled Mandaean refugees (N = 315). Trauma, loss, posttraumatic stress disorder, depression, complicated grief, and mental health-related quality of life were assessed. A multilevel path analysis revealed that loss and trauma significantly impacted on psychological outcomes at both the individual and family levels. Effect sizes ranged from .21 to .68 at the individual level, and .38 to .99 at the family level, highlighting the importance of the family when considering the psychological impact of refugee-related trauma. Copyright © 2011 International Society for Traumatic Stress Studies.

  10. Loss Analysis of Induction Motors Considering Carrier Harmonics of PWM Inverters

    NASA Astrophysics Data System (ADS)

    Yamazaki, Katsumi; Abe, Yoshihiro

    The losses of induction motors driven by PWM inverters are analyzed using the finite element method considering the carrier harmonics. The calculated results are compared with the experimental ones. To consider the effect of the carrier, the theoretical voltage waveform due to the switching pattern of the inverter is given to the analysis by coupling the primary voltage equation and the finite element formulation. The method to decompose the electromagnetic field distribution into time-harmonic components is introduced in order to investigate the effects of the harmonic fields separately and to specify the main loss factors. It is clarified that the rotor surface loss especially increases due to the carrier and that the accuracy of the calculated characteristics of the motor is improved by considering the carrier.

  11. A pressure-sensitive fiber optic connector for loss analysis of physical contact

    NASA Astrophysics Data System (ADS)

    Gong, Zhenfeng; Chen, Ke; Wang, Wei; Yang, Yang; Peng, Wei; Yu, Qingxu; Zhou, Xinlei

    2017-07-01

    We design and fabricate a physical contact (PC) type pressure-sensitive fiber optic connector (FOC), which can be used to measure the contact force and analyze the contact loss caused by the contact force between two PC type FOCs. A fiber Bragg grating (FBG) is wrote on the fiber tip of the connector. The relationship between the Bragg wavelength of the FBG and the contact force exerted on the connector head is got by experiment with a stress sensitivity of 5.4 pm/N. We use this pressure-sensitive FOC for loss analysis of PC type FOCs. The relationships between contact force and insertion loss (IL) of three PC type FOCs have been got experimentally. Finally, finite element simulation results demonstrate the effectiveness of the system.

  12. Depolarized light scattering from prolate anisotropic particles: The influence of the particle shape on the field autocorrelation function.

    PubMed

    Passow, Christopher; ten Hagen, Borge; Löwen, Hartmut; Wagner, Joachim

    2015-07-28

    We provide a theoretical analysis for the intermediate scattering function typically measured in depolarized dynamic light scattering experiments. We calculate the field autocorrelation function g1(VH)(Q,t) in dependence on the wave vector Q and the time t explicitly in a vertical-horizontal scattering geometry for differently shaped solids of revolution. The shape of prolate cylinders, spherocylinders, spindles, and double cones with variable aspect ratio is expanded in rotational invariants flm(r). By Fourier transform of these expansion coefficients, a formal multipole expansion of the scattering function is obtained, which is used to calculate the weighting coefficients appearing in the depolarized scattering function. In addition to translational and rotational diffusion, especially the translational-rotational coupling of shape-anisotropic objects is considered. From the short-time behavior of the intermediate scattering function, the first cumulants Γ(Q) are calculated. In a depolarized scattering experiment, they deviate from the simple proportionality to Q(2). The coefficients flm(Q) strongly depend on the geometry and aspect ratio of the particles. The time dependence, in addition, is governed by the translational and rotational diffusion tensors, which are calculated by means of bead models for differently shaped particles in dependence on their aspect ratio. Therefore, our analysis shows how details of the particle shape--beyond their aspect ratio--can be determined by a precise scattering experiment. This is of high relevance in understanding smart materials which involve suspensions of anisotropic colloidal particles.

  13. Real-time evaluation of an image analysis system for monitoring surgical hemoglobin loss.

    PubMed

    Konig, Gerhardt; Waters, Jonathan H; Javidroozi, Mazyar; Philip, Bridget; Ting, Vicki; Abbi, Gaurav; Hsieh, Eric; Tully, Griffeth; Adams, Gregg

    2017-04-07

    Monitoring blood loss is important for management of surgical patients. This study reviews a device (Triton) that uses computer analysis of a photograph to estimate hemoglobin (Hb) mass present on surgical sponges. The device essentially does what a clinician does when trying to make a visual estimation of blood loss by looking at a sponge, albeit with less subjective variation. The performance of the Triton system is reported upon in during real-time use in surgical procedures. The cumulative Hb losses estimated using the Triton system for 50 enrolled patients were compared with reference Hb measurements during the first quarter, half, three-quarters and full duration of the surgery. Additionally, the estimated blood loss (EBL) was calculated using the Triton measured Hb loss and compared with values obtained from both visual estimation and gravimetric measurements. Hb loss measured by Triton correlated with the reference method across the four measurement intervals. Bias remained low and increased from 0.1 g in the first quarter to 3.7 g at case completion. The limits of agreement remained narrow and increased proportionally from the beginning to the end of the cases, reaching a maximum range of -15.3 to 22.7 g. The median (IQR) difference of EBL derived from the Triton system, gravimetric method and visual estimation versus the reference value were 13 (74), 389 (287), and 4 (230) mL, respectively. Use of the Triton system to measure Hb loss in real-time during surgery is feasible and accurate.

  14. Can no-tillage reduce nitrate and phosphorus loss? A meta-analysis

    NASA Astrophysics Data System (ADS)

    Daryanto, S.; Wang, L.; Jacinthe, P. A.

    2016-12-01

    Alternative land management practices, particularly no-tillage (NT), have been promoted to improve yield and to reduce nitrate (NO3-) and phosphorus (P) to the environment. The outcomes, however, have been variable. To address the uncertainty, we conducted a meta-analysis to obtain robust results of NT on reducing NO3- and P loss in comparison with conventional tillage (CT) using hydrological condition, transport pathway, soil texture, tillage duration, crop species, and their interactions as the co-varying factors. Overall, NT was more efficient than CT in reducing NO3- leaching via groundwater (-16%) and in deep soil water (-26%), and from coarse- (-20%) and medium-textured soils (-18%). NT management, however, could not reduce NO3- loss from runoff and fine-textured soils, likely due to crust and macropores development. While we expected that greater NO3- reduction would proportionally correspond with the duration of NT application, results might vary depending on transport pathway. The effect of NT on NO3- loss was more pronounced during wet years and interacted with transport pathway and soil texture. The effect of crop species was less significant in determining NO3- loss, particularly when sub-surface artificial drainage was applied. In contrast to NO3-, NT management increased dissolved P loss regardless of all the co-varying factors and even at greater extent when the fields were planted with soybean. This study provides the first comprehensive assessment of NT on nutrient loss from agricultural fields and suggests that complementary land management practices in combination with NT are necessary to minimize nutrient loss.

  15. A Systematic Review and Meta-Analysis of Mobile Devices and Weight Loss with an Intervention Content Analysis

    PubMed Central

    Lyzwinski, Lynnette Nathalie

    2014-01-01

    Introduction: Overweight and obesity constitute leading global public health challenges. Tackling overweight and obesity by influencing human behaviour is a complex task, requiring novel emerging health psychology interventions. The aims of this review will be to determine whether mobile devices induce weight loss and improvements in diet and physical activity levels when compared with standard controls without a weight loss intervention or controls allocated to non-mobile device weight loss interventions. Methods: A systematic review on mobile devices and weight loss was conducted. The inclusion criteria were all randomized controlled trials with baseline and post-intervention weight measures in adult subjects >18 years of age without pre-specified co-morbidities. Mobile device specifications included modern, portable devices in the form of smartphones, PDAs, iPods, and Mp3 players. Cohen’s d for standardized differences in mean weight loss was calculated. A random effects meta-analysis was generated using Comprehensive meta-analysis software. Theories and intervention content were coded and analysed. Results: A total of 17 studies were identified, of which 12 were primary trials and 5 were secondary analyses. The meta-analysis generated a medium significant effect size of 0.430 (95% CI 0.252–0.609) (p-value ≤ 0.01), favouring mobile interventions. Throughout the systematic review, mobile devices were found to induce weight loss relative to baseline weight. When comparing them with standard no intervention controls as well as controls receiving non-mobile weight loss interventions, results favoured mobile devices for weight loss. Reductions in Body mass index, waist circumference, and percentage body fat were also found in the review. Improvements in the determinants of weight loss in the form of improved dietary intake and physical activity levels were also found. Theory appears to largely inform intervention design, with the most common theories being

  16. A systematic review and meta-analysis of mobile devices and weight loss with an intervention content analysis.

    PubMed

    Lyzwinski, Lynnette Nathalie

    2014-06-30

    Overweight and obesity constitute leading global public health challenges. Tackling overweight and obesity by influencing human behaviour is a complex task, requiring novel emerging health psychology interventions. The aims of this review will be to determine whether mobile devices induce weight loss and improvements in diet and physical activity levels when compared with standard controls without a weight loss intervention or controls allocated to non-mobile device weight loss interventions. A systematic review on mobile devices and weight loss was conducted. The inclusion criteria were all randomized controlled trials with baseline and post-intervention weight measures in adult subjects >18 years of age without pre-specified co-morbidities. Mobile device specifications included modern, portable devices in the form of smartphones, PDAs, iPods, and Mp3 players. Cohen's d for standardized differences in mean weight loss was calculated. A random effects meta-analysis was generated using Comprehensive meta-analysis software. Theories and intervention content were coded and analysed. A total of 17 studies were identified, of which 12 were primary trials and 5 were secondary analyses. The meta-analysis generated a medium significant effect size of 0.430 (95% CI 0.252-0.609) (p-value ≤ 0.01), favouring mobile interventions. Throughout the systematic review, mobile devices were found to induce weight loss relative to baseline weight. When comparing them with standard no intervention controls as well as controls receiving non-mobile weight loss interventions, results favoured mobile devices for weight loss. Reductions in Body mass index, waist circumference, and percentage body fat were also found in the review. Improvements in the determinants of weight loss in the form of improved dietary intake and physical activity levels were also found. Theory appears to largely inform intervention design, with the most common theories being Social Cognitive Theory, Elaboration

  17. Network Analysis Implicates Alpha-Synuclein (Snca) in the Regulation of Ovariectomy-Induced Bone Loss

    PubMed Central

    Calabrese, Gina; Mesner, Larry D.; Foley, Patricia L.; Rosen, Clifford J.; Farber, Charles R.

    2016-01-01

    The postmenopausal period in women is associated with decreased circulating estrogen levels, which accelerate bone loss and increase the risk of fracture. Here, we gained novel insight into the molecular mechanisms mediating bone loss in ovariectomized (OVX) mice, a model of human menopause, using co-expression network analysis. Specifically, we generated a co-expression network consisting of 53 gene modules using expression profiles from intact and OVX mice from a panel of inbred strains. The expression of four modules was altered by OVX, including module 23 whose expression was decreased by OVX across all strains. Module 23 was enriched for genes involved in the response to oxidative stress, a process known to be involved in OVX-induced bone loss. Additionally, module 23 homologs were co-expressed in human bone marrow. Alpha synuclein (Snca) was one of the most highly connected “hub” genes in module 23. We characterized mice deficient in Snca and observed a 40% reduction in OVX-induced bone loss. Furthermore, protection was associated with the altered expression of specific network modules, including module 23. In summary, the results of this study suggest that Snca regulates bone network homeostasis and ovariectomy-induced bone loss. PMID:27378017

  18. Rapid and Reliable Detection of Nonsyndromic Hearing Loss Mutations by Multicolor Melting Curve Analysis

    PubMed Central

    Wang, Xudong; Hong, Yongjun; Cai, Peihong; Tang, Ning; Chen, Ying; Yan, Tizhen; Liu, Yinghua; Huang, Qiuying; Li, Qingge

    2017-01-01

    Hearing loss is a common birth defect worldwide. The GJB2, SLC26A4, MT-RNR1 and MT-TS1 genes have been reported as major pathogenic genes in nonsyndromic hearing loss. Early genetic screening is recommended to minimize the incidence of hearing loss. We hereby described a multicolor melting curve analysis (MMCA)-based assay for simultaneous detection of 12 prevalent nonsyndromic hearing loss-related mutations. The three-reaction assay could process 30 samples within 2.5 h in a single run on a 96-well thermocycler. Allelic types of each mutation could be reproducibly obtained from 10 pg ~100 ng genomic DNA per reaction. For the mitochondrial mutations, 10% ~ 20% heteroplasmic mutations could be detected. A comparison study using 501 clinical samples showed that the MMCA assay had 100% concordance with both SNaPshot minisequencing and Sanger sequencing. We concluded that the MMCA assay is a rapid, convenient and cost-effective method for detecting the common mutations, and can be expectedly a reliable tool in preliminary screening of nonsyndromic hearing loss in the Chinese Han population. PMID:28225033

  19. A comparative study of the phenyl ring motion in styrene oligomers and polystyrene using FIR absorption and depolarized Rayleigh wing spectra

    NASA Astrophysics Data System (ADS)

    Zoidis, E.; Borsdorf, Ch.; Strehle, F.; Dorfmüller, Th.

    1992-12-01

    FIR absorption and depolarized Rayleigh wing spectra of styrene oligomer model compounds and polystyrene standards with a narrow molecular weight distribution were recorded at various temperatures below and above the glass transition point. For a comparative discussion of the spectral properties we have used the reduced depolarized Rayleigh spectrum RVH( overlineν). In the case of cumene, 2,4-diphenylpentane and 2,4,6-triphenylheptane we were able to fit the well-known Mori function, which is often used to describe FIR absorption spectra of dipolar simple liquids, on the experimental data points. The analysis of the theoretical and band shape parameters obtained from the spectra measured as a function of chain length and temperature allows us to assume that the phenyl ring librational motion may be considered as the main dynamical process shaping the low-frequency part in the FIR absorption spectrum as well as in the depolarized Rayleigh wing of polystyrene.

  20. Linear depolarization of lidar returns by aged smoke particles.

    PubMed

    Mishchenko, Michael I; Dlugach, Janna M; Liu, Li

    2016-12-10

    We use the numerically exact (superposition) T-matrix method to analyze recent measurements of the backscattering linear depolarization ratio (LDR) for a plume of aged smoke at lidar wavelengths ranging from 355 to 1064 nm. We show that the unique spectral dependence of the measured LDRs can be modeled, but only by assuming expressly nonspherical morphologies of smoke particles containing substantial amounts of nonabsorbing (or weakly absorbing) refractory materials such as sulfates. Our results demonstrate that spectral backscattering LDR measurements can be indicative of the presence of morphologically complex smoke particles, but additional (e.g., passive polarimetric or bistatic lidar) measurements may be required for a definitive characterization of the particle morphology and composition.

  1. Matrix Formalism for Spin Dynamics Near a Single Depolarization Resonance

    SciTech Connect

    Chao, Alexander W.; /SLAC

    2005-10-26

    A matrix formalism is developed to describe the spin dynamics in a synchrotron near a single depolarization resonance as the particle energy (and therefore its spin precession frequency) is varied in a prescribed pattern as a function of time such as during acceleration. This formalism is first applied to the case of crossing the resonance with a constant crossing speed and a finite total step size, and then applied also to other more involved cases when the single resonance is crossed repeatedly in a prescribed manner consisting of linear ramping segments or sudden jumps. How repeated crossings produce an interference behavior is discussed using the results obtained. For a polarized beam with finite energy spread, a spin echo experiment is suggested to explore this interference effect.

  2. Depolarization of light backscattered by randomly oriented nonspherical particles.

    PubMed

    Mishchenko, M I; Hovenier, J W

    1995-06-15

    We derive theoretically and validate numerically general relationships for the elements of the backscattering matrix and for the linear, delta(L), and circular, delta(C), backscattering depolarization ratios for nonspherical particles in random orientation. For the practically important case of randomly oriented particles with a plane of symmetry or particles and their mirror particles occurring in equal numbers and in random orientation, delta(C) = 2delta(L)/(1 - delta(L)). Extensive T-matrix computations for randomly oriented spheroids demonstrate that, although both delta(L) and delta(C) are indicators of particle nonsphericity, they cannot be considered a universal measure of the departure of particle shape from that of a sphere and have no simple dependence on particle size and refractive index.

  3. Physiological cytosolic Ca2+ transients evoke concurrent mitochondrial depolarizations.

    PubMed

    Loew, L M; Carrington, W; Tuft, R A; Fay, F S

    1994-12-20

    Calcium, a ubiquitous second messenger, stimulates the activity of several mitochondrial dehydrogenases. This has led to the suggestion that the same messenger that signals cell activation could also activate mitochondrial electron/proton transport, thereby meeting demands for increased cellular energy. To test this in live cells, quantitative three-dimensional microscopy and ratio imaging were used to measure membrane potential of individual mitochondria and cytosolic calcium distribution. Mitochondria reversibly depolarized as cytosolic calcium rose and then fell following physiological stimulation. Thus, the dominant response of the mitochondrion to a rise in cytosolic [Ca2+] is to draw on the electrochemical potential, possibly to accelerate processes directly involved in ATP synthesis and calcium homeostasis.

  4. Special Effects: Antenna Wetting, Short Distance Diversity and Depolarization

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.

    2000-01-01

    The Advanced Communication Technology Satellite (ACTS) communications system operates in the Ka frequency band. ACTS uses multiple, hopping, narrow beams and very small aperture terminal (VSAT) technology to establish a system availability of 99.5% for bit-error-rates of 5 x 10(exp -7) Or better over the continental United States. In order maintain this minimum system availability in all US rain zones, ACTS uses an adaptive rain fade compensation protocol to reduce the impact of signal attenuation resulting from propagation effects. The purpose of this paper is to present the results of system and sub-system characterizations considering the statistical effects of system variances due to antenna wetting and depolarization effects. In addition the availability enhancements using short distance diversity in a sub-tropical rain zone are investigated.

  5. Neutron depolarization measurements of magnetite in chiton teeth

    NASA Astrophysics Data System (ADS)

    Seifert, M.; Schulz, M.; Benka, G.; Pfleiderer, C.; Gilder, S.

    2017-06-01

    Magnetite constitutes one of the most abundant magnetic minerals in the Earth's crust. In the single domain state, magnetite often carries the magnetic remanence in rocks due to its stable and strong magnetic remanence. Hence it is of keen interest to paleomagnetists who study the ancient magnetic field preserved in the rock record. The extremely small size range and vulnerability to oxidation of single domain magnetite makes synthetization and preservation virtually impossible. Consequently, most experimental work on magnetite under pressure is carried out on multidomain magnetite. The radula of the marine mollusc chiton (Polyplacophora) is one of the few natural sources of single domain magnetite. We have performed a comparative study on samples of chiton radula in a vibrating sample magnetometer (VSM) and with the newly evolving neutron depolarization imaging (NDI) technique. Despite a constant offset between the VSM and NDI data in the coercivity we find a good agreement between the two techniques.

  6. Inflections in threshold electrotonus to depolarizing currents in sensory axons.

    PubMed

    Burke, David; Howells, James; Trevillion, Louise; Kiernan, Matthew C; Bostock, Hugh

    2007-12-01

    Threshold electrotonus involves tracking the changes in axonal excitability produced by subthreshold polarizing currents and is the only technique that allows insight into the function of internodal conductances in human subjects in vivo. There is often an abrupt transient reversal of the threshold change as excitability increases in response to conditioning depolarizing currents (S1 phase). In recordings from motor axons, it has been recently demonstrated that this notch or inflection is due to activation of low-threshold axons. We report that a notch is frequently seen in sensory recordings (in 33 of 50 healthy subjects) using the standard threshold electrotonus protocol. When large, the notch can distort subsequent phases of threshold electrotonus and could complicate quantitative measurements and modeling studies.

  7. Compensating Faraday Depolarization by Magnetic Helicity in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Brandenburg, Axel; Ashurova, Mohira B.; Jabbari, Sarah

    2017-08-01

    A turbulent dynamo in spherical geometry with an outer corona is simulated to study the sign of magnetic helicity in the outer parts. In agreement with earlier studies, the sign in the outer corona is found to be opposite to that inside the dynamo. Line-of-sight observations of polarized emission are synthesized to explore the feasibility of using the local reduction of Faraday depolarization to infer the sign of helicity of magnetic fields in the solar corona. This approach was previously identified as an observational diagnostic in the context of galactic magnetic fields. Based on our simulations, we show that this method can be successful in the solar context if sufficient statistics are gathered by using averages over ring segments in the corona separately for the regions north and south of the solar equator.

  8. Physical model of differential Mueller matrix for depolarizing uniform media.

    PubMed

    Devlaminck, Vincent

    2013-11-01

    In this article, we address the question of significance of the parameters of differential Mueller matrix formalism. We show how the concept of mean value and uncertainty of the optical properties recently introduced to depict this differential matrix can be related to the random fluctuations of these optical properties. From the layered-medium interpretation introduced by Jones [J. Opt. Soc. Am. 38, 671 (1948)] and extended to Mueller-Jones matrix by Azzam [J. Opt. Soc. Am. 68, 1756 (1978)], a generalization to depolarizing Mueller matrices is proposed. Based on the random Mueller-Jones matrix approach, the obtained parameterization perfectly fits the previous results from the literature. Necessary conditions of positivity on specific coefficients imposed in order to have physical Mueller matrix are introduced in a natural way and not inferred a posteriori. Interpretations of the underlying physical processes are also presented. An illustrative experimental example is provided from literature data.

  9. Thermal analysis and evolution of shape loss phenomena during polymer burnout in powder metal processing

    NASA Astrophysics Data System (ADS)

    Enneti, Ravi Kumar

    2005-07-01

    Powder metallurgy technology involves manufacturing of net shape or near net shape components starting from metal powders. Polymers are used to provide lubrication during shaping and handling strength to the shaped component. After shaping, the polymers are removed from the shaped components by providing thermal energy to burnout the polymers. Polymer burnout is one of the most critical step in powder metal processing. Improper design of the polymer burnout cycle will result in formation of defects, shape loss, or carbon contamination of the components. The effect of metal particles on polymer burnout and shape loss were addressed in the present research. The study addressing the effect of metal powders on polymer burnout was based on the hypothesis that metal powders act to catalyze polymer burnout. Thermogravimetric analysis (TGA) on pure polymer, ethylene vinyl acetate (EVA), and on admixed powders of 316L stainless steel and 1 wt. % EVA were carried out to verify the hypothesis. The effect of metal powders additions was studied by monitoring the onset temperature for polymer degradation and the temperature at which maximum rate of weight loss occurred from the TGA data. The catalytic behavior of the powders was verified by varying the particle size and shape of the 316L stainless powder. The addition of metal particles lowered the polymer burnout temperatures. The onset temperature for burnout was found to be sensitive to the surface area of the metal particle as well as the polymer distribution. Powders with low surface area and uniform distribution of polymer showed a lower burnout temperature. The evolution of shape loss during polymer burnout was based on the hypothesis that shape loss occurs during the softening of the polymer and depends on the sequence of chemical bonding in the polymer during burnout. In situ observation of shape loss was carried out on thin beams compacted from admixed powders of 316L stainless steel and 1 wt. % ethylene vinyl acetate

  10. Correlation between postoperative weight loss and diabetes mellitus remission: a meta-analysis.

    PubMed

    Yan, Yon-xin; Wang, Guo-feng; Xu, Ning; Wang, Feng-li

    2014-11-01

    This meta-analysis was conducted to determine the effect of percent excess weight loss (%EWL) after bariatric surgery on diabetes remission. The Cochrane Library, PubMed, MEDLINE, Embase, and CINAHL were searched. All reports on %EWL involving humans and published in English between 1 January 1992 and 1 September 2013 were included in the analysis. Eight studies involving 1,247 patients who underwent bariatric surgery were selected. %EWL was positively associated with remission rate (WMD = 11.15, 95 % CI: 6.73-15.56, p < 0.01) in the Caucasian population. Patients with extensive weight loss were more likely to achieve T2DM remission after bariatric surgery. Further randomized controlled trials (RCTs) with uniform remission criterion should be performed to provide more reliable evidence.

  11. Analysis of loss of decay-heat-removal sequences at Browns Ferry Unit One

    SciTech Connect

    Harrington, R.M.

    1983-01-01

    This paper summarizes the Oak Ridge National Laboratory (ORNL) report Loss of DHR Sequences at Browns Ferry Unit One - Accident Sequence Analysis (NUREG/CR-2973). The Loss of DHR investigation is the third in a series of accident studies concerning the BWR 4 - MK I containment plant design. These studies, sponsored by the Nuclear Regulatory Commission Severe Accident Sequence Analysis (SASA) program, have been conducted at ORNL with the full cooperation of the Tennessee Valley Authority (TVA). The purpose of the SASA studies is to predetermine the probable course of postulated severe accidents so as to establish the timing and the sequence of events. The SASA studies also produce recommendations concerning the implementation of better system design and better emergency operating instructions and operator training. The ORNL studies also include a detailed, best-estimate calculation of the release and transport of radioactive fission products following postulated severe accidents.

  12. An estimation method of the fault wind turbine power generation loss based on correlation analysis

    NASA Astrophysics Data System (ADS)

    Zhang, Tao; Zhu, Shourang; Wang, Wei

    2017-01-01

    A method for estimating the power generation loss of a fault wind turbine is proposed in this paper. In this method, the wind speed is estimated and the estimated value of the loss of power generation is given by combining the actual output power characteristic curve of the wind turbine. In the wind speed estimation, the correlation analysis is used, and the normal operation of the wind speed of the fault wind turbine is selected, and the regression analysis method is used to obtain the estimated value of the wind speed. Based on the estimation method, this paper presents an implementation of the method in the monitoring system of the wind turbine, and verifies the effectiveness of the proposed method.

  13. Comparative genomic analysis of tumors: detection of DNA losses and amplification.

    PubMed Central

    Lisitsyn, N A; Lisitsina, N M; Dalbagni, G; Barker, P; Sanchez, C A; Gnarra, J; Linehan, W M; Reid, B J; Wigler, M H

    1995-01-01

    We demonstrate the use of representational difference analysis for cloning probes that detect DNA loss and amplification in tumors. Using DNA isolated from human tumor cell lines to drive hybridization against matched normal DNA, we were able to identify six genomic regions that are homozygously deleted in cultured cancer cells. When this method was applied in the reverse way, using normal DNA to drive hybridization against tumor cell DNA, we readily isolated probes detecting amplification. Representational difference analysis was also performed on DNAs derived from tumor biopsies, and we thereby discovered a probe detecting very frequent homozygous loss in colon cancer cell lines and located on chromosome 3p. Images Fig. 1 Fig. 2 PMID:7816807

  14. Acute Ethanol Causes Hepatic Mitochondrial Depolarization in Mice: Role of Ethanol Metabolism

    PubMed Central

    Zhong, Zhi; Ramshesh, Venkat K.; Rehman, Hasibur; Liu, Qinlong; Theruvath, Tom P.; Krishnasamy, Yasodha; Lemasters, John J.

    2014-01-01

    Background/Aims An increase of ethanol metabolism and hepatic mitochondrial respiration occurs in vivo after a single binge of alcohol. Here, our aim was to determine how ethanol intake affects hepatic mitochondrial polarization status in vivo in relation to ethanol metabolism and steatosis. Methods Hepatic mitochondrial polarization, permeability transition (MPT), and reduce pyridine nucleotides, and steatosis in mice were monitored by intravital confocal/multiphoton microscopy of the fluorescence of rhodamine 123 (Rh123), calcein, NAD(P)H, and BODIPY493/503, respectively, after gavage with ethanol (1–6 g/kg). Results Mitochondria depolarized in an all-or-nothing fashion in individual hepatocytes as early as 1 h after alcohol. Depolarization was dose- and time-dependent, peaked after 6 to 12 h and maximally affected 94% of hepatocytes. This mitochondrial depolarization was not due to onset of the MPT. After 24 h, mitochondria of most hepatocytes recovered normal polarization and were indistinguishable from untreated after 7 days. Cell death monitored by propidium iodide staining, histology and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) was low throughout. After alcohol, mitochondrial NAD(P)H autofluorescence increased and decreased, respectively, in hepatocytes with polarized and depolarized mitochondria. Ethanol also caused steatosis mainly in hepatocytes with depolarized mitochondria. Depolarization was linked to ethanol metabolism, since deficiency of alcohol dehydrogenase and cytochrome-P450 2E1 (CYP2E1), the major ethanol-metabolizing enzymes, decreased mitochondrial depolarization by ∼70% and ∼20%, respectively. Activation of aldehyde dehydrogenase decreased depolarization, whereas inhibition of aldehyde dehydrogenase enhanced depolarization. Activation of aldehyde dehydrogenase also markedly decreased steatosis. Conclusions Acute ethanol causes reversible hepatic mitochondrial depolarization in vivo that may contribute to

  15. Are asymmetric stretch Raman spectra by centrosymmetric molecules depolarized?: The 2ν3 overtone of CO2

    NASA Astrophysics Data System (ADS)

    Chrysos, M.; Verzhbitskiy, I. A.; Rachet, F.; Kouzov, A. P.

    2011-01-01

    Molecular vibrations that are not totally symmetrical give rise to depolarized lines [P. Atkins and J. de Paula, Atkins' Physical Chemistry (Oxford University Press, UK, 2006), p. 464]. But in the case of stretching vibrations in centrosymmetric molecules, the statement has so far not been conclusively verified. It is the purpose of this article to report a rigorous experimental and theoretical analysis of the 2ν _3 band of CO2—the first overtone of the asymmetrical stretch vibration. The anisotropic spectrum was extracted and its spectral moment calculated from light-scattering measurements, taken at room temperature and for a wide range of CO2-gas densities. Evidence for a near-entirely depolarized Raman band is provided, with integrated depolarization ratio η _{int}= 6/7.16, closely approaching the upper bound η _{max}=6/7. Agreement with theoretical predictions is found, on the basis of quality ab initio data for polarizability properties, provided that electro-optical and mechanical anharmonicity and intermode coupling effects between symmetric ν _1 and antisymmetric ν _3 stretching vibrations are incorporated.

  16. Children with unilateral hearing loss may have lower intelligence quotient scores: A meta-analysis.

    PubMed

    Purcell, Patricia L; Shinn, Justin R; Davis, Greg E; Sie, Kathleen C Y

    2016-03-01

    In this meta-analysis, we reviewed observational studies investigating differences in intelligence quotient (IQ) scores of children with unilateral hearing loss compared to children with normal hearing. PubMed Medline, Cumulative Index to Nursing and Allied Health Literature, Embase, PsycINFO. A query identified all English-language studies related to pediatric unilateral hearing loss published between January 1980 and December 2014. Titles, abstracts, and articles were reviewed to identify observational studies reporting IQ scores. There were 261 unique titles, with 29 articles undergoing full review. Four articles were identified, which included 173 children with unilateral hearing loss and 202 children with normal hearing. Ages ranged from 6 to 18 years. Three studies were conducted in the United States and one in Mexico. All were of high quality. All studies reported full-scale IQ results; three reported verbal IQ results; and two reported performance IQ results. Children with unilateral hearing loss scored 6.3 points lower on full-scale IQ, 95% confidence interval (CI) [-9.1, -3.5], P value < 0.001; and 3.8 points lower on performance IQ, 95% CI [-7.3, -0.2], P value 0.04. When investigating verbal IQ, we detected substantial heterogeneity among studies; exclusion of the outlying study resulted in significant difference in verbal IQ of 4 points, 95% CI [-7.5, -0.4], P value 0.028. This meta-analysis suggests children with unilateral hearing loss have lower full-scale and performance IQ scores than children with normal hearing. There also may be disparity in verbal IQ scores. Laryngoscope, 126:746-754, 2016. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

  17. Weight loss intervention adherence and factors promoting adherence: a meta-analysis

    PubMed Central

    Lemstra, Mark; Bird, Yelena; Nwankwo, Chijioke; Rogers, Marla; Moraros, John

    2016-01-01

    Background Adhering to weight loss interventions is difficult for many people. The majority of those who are overweight or obese and attempt to lose weight are simply not successful. The objectives of this study were 1) to quantify overall adherence rates for various weight loss interventions and 2) to provide pooled estimates for factors associated with improved adherence to weight loss interventions. Methods We performed a systematic literature review and meta-analysis of all studies published between January 2004 and August 2015 that reviewed weight loss intervention adherence. Results After applying inclusion and exclusion criteria and checking the methodological quality, 27 studies were included in the meta-analysis. The overall adherence rate was 60.5% (95% confidence interval [CI] 53.6–67.2). The following three main variables were found to impact adherence: 1) supervised attendance programs had higher adherence rates than those with no supervision (rate ratio [RR] 1.65; 95% CI 1.54–1.77); 2) interventions that offered social support had higher adherence than those without social support (RR 1.29; 95% CI 1.24–1.34); and 3) dietary intervention alone had higher adherence than exercise programs alone (RR 1.27; 95% CI 1.19–1.35). Conclusion A substantial proportion of people do not adhere to weight loss interventions. Programs supervising attendance, offering social support, and focusing on dietary modification have better adherence than interventions not supervising attendance, not offering social support, and focusing exclusively on exercise. PMID:27574404

  18. Periodontitis, implant loss and peri-implantitis. A meta-analysis.

    PubMed

    Sgolastra, F; Petrucci, A; Severino, M; Gatto, R; Monaco, A

    2015-04-01

    The aim of the present systematic review and meta-analysis was to assess the role of periodontal disease as a risk factor for implant loss, peri-implantitis and implant-bone loss. Six electronic database and a manual search resulted in 7391 unique publications; after selection only 16 studies were included in systematic review. Dichotomous data were expressed as risk ratio (RR) and 95% confidence interval (CI), while continuous data were expressed as standardized mean difference (SMD). Due to the expected inter-study heterogeneity, a random effect model was used for both type of data. The pooled effect was considered significant for a P < 0.05. Meta-analysis revealed that an higher and significant risk for implant loss was present in patients affected by PD (RR: 1.69, 95% CI: 1.31-2.17, P < 0.0001). A higher and significant IBL was present in patients with periodontal disease, when compared with patients periodontally healthy (SMD: 0.38, 95% CI: 0.18-0.58, P = 0.0002). Patients periodontally compromised showed an increased risk of PI, when compared with patients without periodontitis (RR: 2.17, 95% CI: 1.51-3.12, P < 0.0001) No evidence of significant heterogeneity was detected for the three outcomes. Strong evidence suggests that periodontitis is a risk factor for implant loss; moderate evidence revealed that periodontitis is a risk factor for peri-implantitis and that patients with periodontitis have higher implant-bone loss. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Intentional Weight Loss and Changes in Symptoms of Depression: A Systematic Review and Meta-Analysis

    PubMed Central

    Fabricatore, Anthony N.; Wadden, Thomas A.; Higginbotham, Allison J.; Faulconbridge, Lucy F.; Nguyen, Allison M.; Heymsfield, Steven B.; Faith, Myles S.

    2011-01-01

    Objective Obesity is related to increased risk of several health complications, including depression. Many studies have reported improvements in mood with weight loss, but results have been equivocal. The present meta-analysis examined changes in symptoms of depression that were reported in trials of weight loss interventions. Between-groups comparisons of different weight loss methods (e.g., lifestyle modification, diet alone, pharmacotherapy) were examined, as were within-group changes for each treatment type. Method MEDLINE was searched for articles published between 1950 and January 2009. Several obesity-related terms were intersected with terms related to depression. Results were filtered to return only studies of human subjects, published in English. Of 5971 articles, 394 were randomized controlled trials. Articles were excluded if they did not report mean changes in weight or symptoms of depression, included children or persons with psychiatric disorders (other than depression), or provided insufficient data for analysis. Thirty-one studies (n = 7937) were included. Two authors independently extracted a description of each study treatment, sample characteristics, assessment methods, and changes in weight and symptoms of depression. Treatments were categorized as: lifestyle modification, non-dieting, dietary counseling, diet-alone, exercise-alone, pharmacotherapy, placebo, or control interventions. Results Random effects models found that lifestyle modification was superior to control and non-dieting interventions for reducing symptoms of depression, and marginally better than dietary counseling and exercise-alone programs. Exercise-alone programs were superior to controls. No differences were found for comparisons of pharmacologic agents and placebos. Within-group analyses found significant reductions in symptoms of depression for nearly all active interventions. A meta-regression found no relationship between changes in weight and changes in symptoms of

  20. Influence of platform switching on periimplant bone loss: a systematic review and meta-analysis.

    PubMed

    Herekar, Manisha; Sethi, Megha; Mulani, Shahnawaz; Fernandes, Aquaviva; Kulkarni, Harish

    2014-08-01

    This meta-analysis aims to systematically review and draw a comparison between conventional implant designs and "platform-switched" implants in terms of crestal bone loss. Electronic (PubMed) and hand searches were conducted. Literature, clinical studies, and case reports pertaining to reduction of crestal bone loss and obtaining better esthetic outcome by platform switching were reviewed till October 2011. Controlled trials comparing marginal bone-level changes around platform-switched and platform-matched implants were selected. For the assessment of accuracy, meta-analysis was performed. The marginal bone loss around platform-switched implants was significantly lesser than platform-matched implants (mean difference [MD]: -0.34; 95% confidence interval [CI]: -0.37 to -0.30; P < 0.00001). According to this review and meta-analysis, platform switching seems to preserve periimplant bone and soft tissue levels. However, long-term clinical studies on the proper diameter of abutment without deformation and the effective degree of platform switching in terms of the bone resorption are still awaited.

  1. Automated Vocal Analysis of Children with Hearing Loss and Their Typical and Atypical Peers

    PubMed Central

    VanDam, Mark; Oller, D. Kimbrough; Ambrose, Sophie E.; Gray, Sharmistha; Richards, Jeffrey A.; Xu, Dongxin; Gilkerson, Jill; Silbert, Noah H.; Moeller, Mary Pat

    2014-01-01

    Objectives This study investigated automatic assessment of vocal development in children with hearing loss as compared with children who are typically developing, have language delays, and autism spectrum disorder. Statistical models are examined for performance in a classification model and to predict age within the four groups of children. Design The vocal analysis system analyzed over 1900 whole-day, naturalistic acoustic recordings from 273 toddlers and preschoolers comprising children who were typically developing, hard of hearing, language delayed, or autistic. Results Samples from children who were hard-of-hearing patterned more similarly to those of typically-developing children than to the language-delayed or autistic samples. The statistical models were able to classify children from the four groups examined and estimate developmental age based on automated vocal analysis. Conclusions This work shows a broad similarity between children with hearing loss and typically developing children, although children with hearing loss show some delay in their production of speech. Automatic acoustic analysis can now be used to quantitatively compare vocal development in children with and without speech-related disorders. The work may serve to better distinguish among various developmental disorders and ultimately contribute to improved intervention. PMID:25587667

  2. Depolarizing stimuli cause persistent and selective loss of orexin in rat hypothalamic slice culture.

    PubMed

    Katsuki, Hiroshi; Kurosu, Shinsuke; Michinaga, Shotaro; Hisatsune, Akinori; Isohama, Yoichiro; Izumi, Yasuhiko; Kume, Toshiaki; Akaike, Akinori

    2010-06-01

    A hypothalamic neuropeptide orexin (hypocretin) is a critical regulator of physiological processes including sleep/wakefulness and feeding. Using organotypic slice culture of rat hypothalamus, we found that exposure to elevated extracellular concentration of K(+) (+10-30 mM) for 24-72h led to a substantial decrease in the number of neurons immunoreactive for orexin and a co-existing neuropeptide dynorphin-A. In contrast, the same treatment affected neither the number of melanin-concentrating hormone-immunoreactive neurons nor the number of total neurons. A substantial decrease of orexin-immunoreactive neurons was also induced by 72h treatment with 1-10 microM veratridine, a Na(+) channel activator. The effect of elevated K(+) was only partially reversible, and that of veratridine was virtually irreversible, although the decrease in orexin immunoreactivity was not associated with signs of cell damage assessed by propidium iodide uptake and Hoechst 33342 nuclear staining. In addition, the level of preproorexin mRNA did not decrease during treatment with elevated K(+) or veratridine. After treatment with elevated K(+) and veratridine, c-Fos immunoreactivity appeared in orexin-immunoreactive neurons but not in melanin-concentrating hormone-immunoreactive neurons, suggesting selective excitation of orexin neurons. However, the amount of orexin released extracellularly was paradoxically decreased by treatment with elevated K(+) and veratridine. Overall, these characteristics of orexin neurons may be taken into consideration to understand the behaviors of these neurons under physiological and pathophysiological conditions.

  3. How Acute Total Sleep Loss Affects the Attending Brain: A Meta-Analysis of Neuroimaging Studies

    PubMed Central

    Ma, Ning; Dinges, David F.; Basner, Mathias; Rao, Hengyi

    2015-01-01

    Study Objectives: Attention is a cognitive domain that can be severely affected by sleep deprivation. Previous neuroimaging studies have used different attention paradigms and reported both increased and reduced brain activation after sleep deprivation. However, due to large variability in sleep deprivation protocols, task paradigms, experimental designs, characteristics of subject populations, and imaging techniques, there is no consensus regarding the effects of sleep loss on the attending brain. The aim of this meta-analysis was to identify brain activations that are commonly altered by acute total sleep deprivation across different attention tasks. Design: Coordinate-based meta-analysis of neuroimaging studies of performance on attention tasks during experimental sleep deprivation. Methods: The current version of the activation likelihood estimation (ALE) approach was used for meta-analysis. The authors searched published articles and identified 11 sleep deprivation neuroimaging studies using different attention tasks with a total of 185 participants, equaling 81 foci for ALE analysis. Results: The meta-analysis revealed significantly reduced brain activation in multiple regions following sleep deprivation compared to rested wakefulness, including bilateral intraparietal sulcus, bilateral insula, right prefrontal cortex, medial frontal cortex, and right parahippocampal gyrus. Increased activation was found only in bilateral thalamus after sleep deprivation compared to rested wakefulness. Conclusion: Acute total sleep deprivation decreases brain activation in the fronto-parietal attention network (prefrontal cortex and intraparietal sulcus) and in the salience network (insula and medial frontal cortex). Increased thalamic activation after sleep deprivation may reflect a complex interaction between the de-arousing effects of sleep loss and the arousing effects of task performance on thalamic activity. Citation: Ma N, Dinges DF, Basner M, Rao H. How acute total

  4. An economic analysis of traditional and technology-based approaches to weight loss.

    PubMed

    Archer, Edward; Groessl, Erik J; Sui, Xuemei; McClain, Amanda C; Wilcox, Sara; Hand, Gregory A; Meriwether, Rebecca A; Blair, Steven N

    2012-08-01

    The financial burden and human losses associated with noncommunicable diseases necessitate cost-effective and efficacious interventions. An economic analysis of the Lifestyle Education for Activity and Nutrition (LEAN) Study; an RCT that examined the efficacy of traditional and technology-based approaches to weight loss. Economic analyses from an organizational perspective were conducted for four approaches: standard care control (SC); group weight-loss education (GWL); a multisensor armband (SWA); and the armband in combination with group weight-loss education (GWL+SWA). Data were collected in 2008-2009. Weight loss was the primary outcome. Total costs, costs per participant, costs per kilogram lost, and incremental cost-effectiveness ratios (ICERs) were calculated in 2010-2011. All costs are the actual expenses (i.e., staff time and materials) incurred by the LEAN study (except where noted) and reported in 2010 U.S. dollars. In the sample population of 197 sedentary, overweight, and obese adults (mean [±SD] age=46.9 ± 0.8 years, BMI=33.3 ± 5.2, weight=92.8 ± 18.4 kg), the GWL+SWA was the most expensive intervention in costs/participant ($365/partic) while yielding the greatest weight loss/partic (6.59 kg). The GWL was next in cost/partic ($240), but the SWA was less expensive in cost/partic ($183) and more efficacious (3.55 vs 1.86 kg/partic). The SC did not achieve significant weight loss. The SWA was the most cost effective ($51/partic/kg lost), followed by the GWL+SWA ($55) and GWL alone ($129). The ICER suggests that for each additional kilogram lost, the GWL+SWA cost $60 more than the SWA alone. The SWA was the most cost-effective intervention ($51/partic/kg lost). The addition of the GWL increased the efficacy of the SWA intervention but increased costs by $60/partic for each additional kilogram lost. The technology-based approaches were more cost effective and efficacious than traditional approaches in promoting weight loss via lifestyle changes in

  5. Evaluation of Implant Collar Surfaces for Marginal Bone Loss: A Systematic Review and Meta-Analysis

    PubMed Central

    2016-01-01

    Background. It is important to understand the influence of different collar designs on peri-implant marginal bone loss, especially in the critical area. Objectives. The purpose of the present systematic review and meta-analysis was to compare dental implants with different collar surfaces, evaluating marginal bone loss and survival rates of implants. Methods. Eligibility criteria included clinical human studies, randomized controlled trials, and prospective and retrospective studies, which evaluated dental implants with different collar surface in the same study. Results. Twelve articles were included, with a total of 492 machined, 319 rough-surfaced, and 352 rough-surfaced microthreaded neck implants. There was less marginal bone loss at implants with rough-surfaced and rough-surfaced microthreaded neck than at machined-neck implants (difference in means: 0.321, 95% CI: 0.149 to 0.493; p < 0.01). Conclusion. Rough and rough-surfaced microthreaded implants are considered a predictable treatment for preserving early marginal bone loss. PMID:27493957

  6. Modelling and loss analysis of meso-structured perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Xue, Hansong; Fu, Kunwu; Wong, Lydia Helena; Birgersson, Erik; Stangl, Rolf

    2017-08-01

    A mathematical model for meso-structured perovskite solar cells is derived and calibrated towards measured intensity dependent current-voltage characteristics. This steady-state device model describes the transport of free carriers, carrier recombination and optical generation. The optical part considers internal transmission, reflection, and absorption of light, using a transfer matrix approach. The carrier recombination in the form of radiative, Auger and Shockley-Read-Hall mechanisms is accounted for inside the perovskite capping layer, as well as interfacial recombination between the perovskite and electron/hole-transporting layers. After calibration by best-fitting the unknown parameters towards intensity dependent current-voltage measurements of an in-house fabricated meso-structured perovskite solar cell, we identify the dominant recombination mechanisms and their locations inside the cell. A subsequent loss analysis indicates that, in our fabricated solar cell, the interfacial recombination between the perovskite/mesoporous titanium dioxide within the mesoporous absorber layer constitutes the main loss channel. This interfacial recombination accounts for up to 46% of all recombination losses at maximum power, thereby exceeding the recombination inside the perovskite capping layer with 31% loss. Furthermore, the thickness of the perovskite capping layer and the mesoporous layer is varied by means of simulation between 50 and 500 nm, in order to predict the optimum device geometry for the calibrated recombination parameters.

  7. Blade loss transient dynamics analysis, volume 1. Task 1: Survey and perspective. [aircraft gas turbine engines

    NASA Technical Reports Server (NTRS)

    Gallardo, V. C.; Gaffney, E. F.; Bach, L. J.; Stallone, M. J.

    1981-01-01

    An analytical technique was developed to predict the behavior of a rotor system subjected to sudden unbalance. The technique is implemented in the Turbine Engine Transient Rotor Analysis (TETRA) computer program using the component element method. The analysis was particularly aimed toward blade-loss phenomena in gas turbine engines. A dual-rotor, casing, and pylon structure can be modeled by the computer program. Blade tip rubs, Coriolis forces, and mechanical clearances are included. The analytical system was verified by modeling and simulating actual test conditions for a rig test as well as a full-engine, blade-release demonstration.

  8. Infrared Thermography of Buildings: Qualitative Analysis of Window Infiltration Loss, Federal Office Building, Burlington, Vermont.

    DTIC Science & Technology

    1977-09-01

    Aa—AON4 942 COI.D REGIONS RESEARCH MC ENGINEERING LAB HANOVER N H F/s t3i s - IPFRARED TICRMOIRAPHY OF BUILDINGS : QUALITATIVE ANALYSIS OF WIN—ETC(U...RECIPIEHT~S CATALOG NUMBER ~~~~~Specia1 ~~~~~J7_2 9 ~ 4. E ~~~~ ~~~~~~~~ 5. TYP E OF REPORT & PERIOD COVERED -ì .,INFRARED ,~HERMOGRAPHY OF~ BUILDINGS ...ua 1itative Analysis of Window Infiltration Loss~ __________________________ J Federal Office Building , ~ urlin~~ on , Vermont

  9. Cortical spreading depolarization increases adult neurogenesis, and alters behavior and hippocampus-dependent memory in mice.

    PubMed

    Urbach, Anja; Baum, Eileen; Braun, Falko; Witte, Otto W

    2017-05-01

    Cortical spreading depolarizations are an epiphenomenon of human brain pathologies and associated with extensive but transient changes in ion homeostasis, metabolism, and blood flow. Previously, we have shown that cortical spreading depolarization have long-lasting consequences on the brains transcriptome and structure. In particular, we found that cortical spreading depolarization stimulate hippocampal cell proliferation resulting in a sustained increase in adult neurogenesis. Since the hippocampus is responsible for explicit memory and adult-born dentate granule neurons contribute to this function, cortical spreading depolarization might influence hippocampus-dependent cognition. To address this question, we induced cortical spreading depolarization in C57Bl/6 J mice by epidural application of 1.5 mol/L KCl and evaluated neurogenesis and behavior at two, four, or six weeks thereafter. Congruent with our previous findings in rats, we found that cortical spreading depolarization increases numbers of newborn dentate granule neurons. Moreover, exploratory behavior and object location memory were consistently enhanced. Reference memory in the water maze was virtually unaffected, whereas memory formation in the Barnes maze was impaired with a delay of two weeks and facilitated after four weeks. These data show that cortical spreading depolarization produces lasting changes in psychomotor behavior and complex, delay- and task-dependent changes in spatial memory, and suggest that cortical spreading depolarization-like events affect the emotional and cognitive outcomes of associated brain pathologies.

  10. A New Technique for Quantitative Analysis of Hair Loss in Mice Using Grayscale Analysis

    PubMed Central

    Ponnapakkam, Tulasi; Katikaneni, Ranjitha; Gulati, Rohan; Gensure, Robert

    2015-01-01

    Alopecia is a common form of hair loss which can occur in many different conditions, including male-pattern hair loss, polycystic ovarian syndrome, and alopecia areata. Alopecia can also occur as a side effect of chemotherapy in cancer patients. In this study, our goal was to develop a consistent and reliable method to quantify hair loss in mice, which will allow investigators to accurately assess and compare new therapeutic approaches for these various forms of alopecia. The method utilizes a standard gel imager to obtain and process images of mice, measuring the light absorption, which occurs in rough proportion to the amount of black (or gray) hair on the mouse. Data that has been quantified in this fashion can then be analyzed using standard statistical techniques (i.e., ANOVA, T-test). This methodology was tested in mouse models of chemotherapy-induced alopecia, alopecia areata and alopecia from waxing. In this report, the detailed protocol is presented for performing these measurements, including validation data from C57BL/6 and C3H/HeJ strains of mice. This new technique offers a number of advantages, including relative simplicity of application, reliance on equipment which is readily available in most research laboratories, and applying an objective, quantitative assessment which is more robust than subjective evaluations. Improvements in quantification of hair growth in mice will improve study of alopecia models and facilitate evaluation of promising new therapies in preclinical studies. PMID:25867252

  11. A new technique for quantitative analysis of hair loss in mice using grayscale analysis.

    PubMed

    Ponnapakkam, Tulasi; Katikaneni, Ranjitha; Gulati, Rohan; Gensure, Robert

    2015-03-09

    Alopecia is a common form of hair loss which can occur in many different conditions, including male-pattern hair loss, polycystic ovarian syndrome, and alopecia areata. Alopecia can also occur as a side effect of chemotherapy in cancer patients. In this study, our goal was to develop a consistent and reliable method to quantify hair loss in mice, which will allow investigators to accurately assess and compare new therapeutic approaches for these various forms of alopecia. The method utilizes a standard gel imager to obtain and process images of mice, measuring the light absorption, which occurs in rough proportion to the amount of black (or gray) hair on the mouse. Data that has been quantified in this fashion can then be analyzed using standard statistical techniques (i.e., ANOVA, T-test). This methodology was tested in mouse models of chemotherapy-induced alopecia, alopecia areata and alopecia from waxing. In this report, the detailed protocol is presented for performing these measurements, including validation data from C57BL/6 and C3H/HeJ strains of mice. This new technique offers a number of advantages, including relative simplicity of application, reliance on equipment which is readily available in most research laboratories, and applying an objective, quantitative assessment which is more robust than subjective evaluations. Improvements in quantification of hair growth in mice will improve study of alopecia models and facilitate evaluation of promising new therapies in preclinical studies.

  12. Physically Realizable Space for the Purity-Depolarization Plane for Polarized Light Scattering Media

    NASA Astrophysics Data System (ADS)

    Tariq, Aziz; Li, Pengcheng; Chen, Dongsheng; Lv, Donghong; Ma, Hui

    2017-07-01

    We propose a physically realizable space for the polarized light scattering measurement using the Stokes-Mueller formalism by a purity-index-depolarization-index (PI -PΔ ) plane. The parameter PI is defined from indices of polarimetric purity (IPP), which exhibits the overall magnitude of the polarimetric randomness of a medium, while the depolarization index (PΔ ) delineates a proper global degree of polarimetric purity and may also refer to the average measure of depolarization power of the scattering medium. Subregions and curves connecting the edge points in the plane are obtained by imposing certain constraints on the IPP; consequently any point on the subregion indicates the information related to a decomposition of the Mueller matrix into its components as a convex sum. From the same set of constraints, complete information about the depolarization index versus the entropy [S (M ) -PΔ ] diagram is recovered. This work provides a simple geometric representation and a deeper perceptivity of the light scattering media comprising depolarization.

  13. Effects of extracellular calcium and sodium on depolarization-induced automaticity in guinea pig papillary muscle.

    PubMed

    Katzung, B G

    1975-07-01

    Regenerative discharge of action potentials is induced in mammalian papillary muscles by passage of small depolarizing currents. In this paper, the effects of various extracellular calcium and sodium concentrations and of tetrodotoxin on this phenomenon were studied in guinea pig papillary muscles in a sucrose gap chamber. Phase 4 diastolic depolarization was found to be associated with an increase in membrane resistance. The slope of phase 4 depolarization was decreased by reductions in extracellular calcium or sodium concentration. The range of maximum diastolic potentials and the thresholds from which regenerative potentials arose were reduced, especially at the positive limit of potentials, by a reduction in either ion. It was concluded that both calcium and sodium influence diastolic depolarization and participate in the regenerative action potentials of depolarization-induced ventricular automaticity.

  14. Analysis and Optimization of Loss Functions for Multiclass, Top-k, and Multilabel Classification.

    PubMed

    Lapin, Maksim; Hein, Matthias; Schiele, Bernt

    2017-09-13

    Top-k error is currently a popular performance measure on large scale image classification benchmarks such as ImageNet and Places. Despite its wide acceptance, our understanding of this metric is limited as most of the previous research is focused on its special case, the top-1 error. In this work, we explore two directions that shed light on the top-k error. First, we provide an in-depth analysis of established and recently proposed single-label multiclass methods along with a detailed account of efficient optimization algorithms for them. Our results indicate that the softmax loss and the smooth multiclass SVM are competitive in top-k error uniformly across all k, which can be explained by our analysis of multiclass top-k calibration. Further improvements are possible with a number of proposed top-k loss functions. Second, we use the top-k methods to explore the transition from multiclass to multilabel learning. In particular, we find that it is possible to obtain effective multilabel classifiers on Pascal VOC using a single label per image for training, while the gap between multiclass and multilabel methods on MS COCO is more significant. Finally, our contribution of efficient algorithms for training with the top-k and multilabel loss functions is of independent interest.

  15. Multivariate analysis of prognostic factors for idiopathic sudden sensorineural hearing loss in children.

    PubMed

    Chung, Jae Ho; Cho, Seok Hyun; Jeong, Jin Hyeok; Park, Chul Won; Lee, Seung Hwan

    2015-09-01

    To evaluate clinical characteristics and possible associated factors of idiopathic sudden sensorineural hearing loss (ISSNHL) in children using univariate and multivariate analyses. A retrospective case series with comparisons. From January 2007 to December 2013, medical records of 37 pediatric ISSNHL patients were reviewed to assess hearing recovery rate and examine factors associated with prognosis (gender; side of hearing loss; opposite side hearing loss; treatment onset; presence of vertigo, tinnitus, and ear fullness; initial hearing threshold), using univariate and multivariate analysis, and compare them with 276 adult ISSNHL patients. Pediatric patients comprised only 6.6% of pediatric/adult cases of ISSNHL, and those below 10 years old were only 0.7%. The overall recovery rates (complete and partial) of the pediatric and adult patients were 57.4% and 47.2%, respectively. The complete recovery rate of the pediatric group (46.6%) was higher than that of the adult group (30.8%, P = .040). According to multivariate analysis, absence of tinnitus, later onset of treatment, and higher hearing threshold at initial presentation were associated with a poor prognosis in pediatric ISSNHL. The recovery rate of ISSNHL in pediatric patients is higher than in adults, and the presence of tinnitus and earlier treatment onset is associated with favorable outcomes. 4. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

  16. Heat loss analysis-based design of a 12 MW wind power generator module having an HTS flux pump exciter

    NASA Astrophysics Data System (ADS)

    Sung, Hae-Jin; Go, Byeong-Soo; Jiang, Zhenan; Park, Minwon; Yu, In-Keun

    2016-11-01

    The development of an effective high-temperature superconducting (HTS) generator is currently a research focus; however, the reduction of heat loss of a large-scale HTS generator is a challenge. This study deals with a heat loss analysis-based design of a 12 MW wind power generator module having an HTS flux pump exciter. The generator module consists of an HTS rotor of the generator and an HTS flux pump exciter. The specifications of the module were described, and the detailed configuration of the module was illustrated. For the heat loss analysis of the module, the excitation loss of the flux pump exciter, eddy current loss of all of the structures in the module, radiation loss, and conduction loss of an HTS coil supporter were assessed using a 3D finite elements method program. In the case of the conduction loss, different types of the supporters were compared to find out the supporter of the lowest conduction loss in the module. The heat loss analysis results of the module were reflected in the design of the generator module and discussed in detail. The results will be applied to the design of large-scale superconducting generators for wind turbines including a cooling system.

  17. Genetic analysis of TMPRSS3 gene in the Korean population with autosomal recessive nonsyndromic hearing loss.

    PubMed

    Lee, Jinwook; Baek, Jeong-In; Choi, Jae Young; Kim, Un-Kyung; Lee, Sang-Heun; Lee, Kyu-Yup

    2013-12-15

    The TMPRSS3 gene (DFNB8/10), which encodes a transmembrane serine protease, is a common hearing loss gene in several populations. Accurate functions of TMPRSS3 in the hearing pathway are still unknown, but TMPRSS3 has been reported to play a crucial role in inner ear development or maintenance. To date, 16 pathogenic mutations have been identified in many countries, but no mutational studies of the TMPRSS3 gene have been conducted in the Korean hearing loss population. In this study, we performed genetic analysis of TMPRSS3 in 40 unrelated Korean patients with autosomal recessive hearing loss to identify the aspect and frequency of TMPRSS3 gene mutations in the Korean population. A total of 22 variations were detected, including a novel variant (p.V291L) and a previously reported pathogenic mutation (p.A306T). The p.A306T mutation which has been detected in only compound heterozygous state in previous studies was identified in homozygous state for the first time in this study. Moreover, the clinical evaluation identified bilateral dilated vestibules in the patient with p.A306T mutation, and it suggested that p.A306T mutation of the TMPRSS3 gene might be associated with vestibular anomalies. In conclusion, this study investigated that only 2.5% of patients with autosomal recessive hearing loss were related to TMPRSS3 mutations suggesting low prevalence of TMPRSS3 gene in Korean hearing loss population. Also, it will provide the information of genotype-phenotype correlation to understand definite role of TMPRSS3 in the auditory system.

  18. Genetic Analysis through OtoSeq of Pakistani Families Segregating Prelingual Hearing Loss

    PubMed Central

    Shahzad, Mohsin; Sivakumaran, Theru A; Qaiser, Tanveer A.; Schultz, Julie M.; Hussain, Zawar; Flanagan, Megan; Bhinder, Munir A.; Kissell, Diane; Greinwald, John H; Khan, Shaheen N.; Friedman, Thomas B.; Zhang, Kejian; Riazuddin, Saima; Riazuddin, Sheikh; Ahmed, Zubair M.

    2014-01-01

    Objective To identify the genetic cause of prelingual sensorineural hearing loss in Pakistani families using a next-generation sequencing (NGS)-based mutation screening test named OtoSeq. Study Design Prospective Study Setting Research laboratory Subjects and Methods We used three fluorescently labeled short tandem repeat (STR) markers for each of the known autosomal recessive nonsyndromic (DFNB) and Usher syndrome (USH) locus to perform a linkage analysis of 243 multi-generational Pakistani families segregating prelingual hearing loss. After genotyping, we focused on 34 families with potential linkage to MYO7A, CDH23 and SLC26A4. We screened affected individuals from a subset of these families using the OtoSeq platform to identify underlying genetic variants. Sanger sequencing was performed to confirm and study the segregation of mutations in other family members. For novel mutations, normal hearing individuals from ethnically matched backgrounds were also tested. Results Hearing loss was found to co-segregate with locus-specific STR markers for MYO7A in 32 families, CDH23 in one family and SLC26A4 in one family. Using the OtoSeq platform, a microdroplet PCR-based enrichment followed by NGS, we identified mutations in 28 of the 34 families including 11 novel mutations. Sanger sequencing of these mutations showed 100% concordance with NGS data and co-segregation of the mutant alleles with the hearing loss phenotype in the respective families. Conclusion Using NGS based platforms like OtoSeq in families segregating hearing loss, will contribute to the identification of common and population specific mutations, early diagnosis, genetic counseling and molecular epidemiology. PMID:23770805

  19. Mediation analysis to estimate direct and indirect milk losses due to clinical mastitis in dairy cattle.

    PubMed

    Detilleux, J; Kastelic, J P; Barkema, H W

    2015-03-01

    Milk losses associated with mastitis can be attributed to either effects of pathogens per se (i.e., direct losses) or effects of the immune response triggered by intramammary infection (indirect losses). The distinction is important in terms of mastitis prevention and treatment. Regardless, the number of pathogens is often unknown (particularly in field studies), making it difficult to estimate direct losses, whereas indirect losses can be approximated by measuring the association between increased somatic cell count (SCC) and milk production. An alternative is to perform a mediation analysis in which changes in milk yield are allocated into their direct and indirect components. We applied this method on data for clinical mastitis, milk and SCC test-day recordings, results of bacteriological cultures (Escherichia coli, Staphylococcus aureus, Streptococcus uberis, coagulase-negative staphylococci, Streptococcus dysgalactiae, and streptococci other than Strep. dysgalactiae and Strep. uberis), and cow characteristics. Following a diagnosis of clinical mastitis, the cow was treated and changes (increase or decrease) in milk production before and after a diagnosis were interpreted counterfactually. On a daily basis, indirect changes, mediated by SCC increase, were significantly different from zero for all bacterial species, with a milk yield decrease (ranging among species from 4 to 33g and mediated by an increase of 1000 SCC/mL/day) before and a daily milk increase (ranging among species from 2 to 12g and mediated by a decrease of 1000 SCC/mL/day) after detection. Direct changes, not mediated by SCC, were only different from zero for coagulase-negative staphylococci before diagnosis (72g per day). We concluded that mixed structural equation models were useful to estimate direct and indirect effects of the presence of clinical mastitis on milk yield. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. [Analysis of the clinical salience for sudden hearing loss in acoustic neuroma].

    PubMed

    Lü, M; Liu, H; Wang, J

    2001-02-01

    To avoid misdiagnosis and misapplied therapy of acoustic neuroma. 92 cases of acoustic neuroma treated between 1983 and 1997 were retrospectively reviewed. Among them, 20 patients (21 ears, 21.7%) presented with sudden hearing loss as the starting symptoms. The diagnosis was based on audiological and radiologic examinations. The clinical and audiological analysis demonstrated that 57.1% of the ears showed hearing loss over 71 dBHL, and all ears had deteriorated ABRs. Acoustic reflex was nonreactive in all 10 ears tested. Positive findings in CT scan were 88.89%. CT pneumoencephalography or MRI provided useful information of diagnosis in those with negative findings of place CT scan. ABR should be used as a routine test for patients with sudden deafness. When ABR was abnormal, CT scan around the internal auditory meatus was needed.

  1. Analysis of performance losses of direct ethanol fuel cells with the aid of a reference electrode

    NASA Astrophysics Data System (ADS)

    Li, Guangchun; Pickup, Peter G.

    The performances of direct ethanol fuel cells with different anode catalysts, different ethanol concentrations, and at different operating temperatures have been studied. The performance losses of the cell have been separated into individual electrode performance losses with the aid of a reference electrode, ethanol crossover has been quantified, and CO 2 and acetic acid production have been measured by titration. It has been shown that the cell performance strongly depends on the anode catalyst, ethanol concentration, and operating temperature. It was found that the cathode and anode exhibit different dependences on ethanol concentration and operating temperature. The performance of the cathode is very sensitive to the rate of ethanol crossover. Product analysis provides insights into the mechanisms of electro-oxidation of ethanol.

  2. Delayed ischaemic neurological deficits after subarachnoid haemorrhage are associated with clusters of spreading depolarizations.

    PubMed

    Dreier, Jens P; Woitzik, Johannes; Fabricius, Martin; Bhatia, Robin; Major, Sebastian; Drenckhahn, Chistoph; Lehmann, Thomas-Nicolas; Sarrafzadeh, Asita; Willumsen, Lisette; Hartings, Jed A; Sakowitz, Oliver W; Seemann, Jörg H; Thieme, Anja; Lauritzen, Martin; Strong, Anthony J

    2006-12-01

    Progressive ischaemic damage in animals is associated with spreading mass depolarizations of neurons and astrocytes, detected as spreading negative slow voltage variations. Speculation on whether spreading depolarizations occur in human ischaemic stroke has continued for the past 60 years. Therefore, we performed a prospective multicentre study assessing incidence and timing of spreading depolarizations and delayed ischaemic neurological deficit (DIND) in patients with major subarachnoid haemorrhage (SAH) requiring aneurysm surgery. Spreading depolarizations were recorded by electrocorticography with a subdural electrode strip placed on cerebral cortex for up to 10 days. A total of 2110 h recording time was analysed. The clinical state was monitored every 6 h. Delayed infarcts after SAH were verified by serial CT scans and/or MRI. Electrocorticography revealed 298 spreading depolarizations in 13 of the 18 patients (72%). A clinical DIND was observed in seven patients 7.8 days (7.3, 8.2) after SAH. DIND was time-locked to a sequence of recurrent spreading depolarizations in every single case (positive and negative predictive values: 86 and 100%, respectively). In four patients delayed infarcts developed in the recording area. As in the ischaemic penumbra of animals, delayed infarction was preceded by progressive prolongation of the electrocorticographic depression periods associated with spreading depolarizations to >60 min in each case. This study demonstrates that spreading depolarizations have a high incidence in major SAH and occur in ischaemic stroke. Repeated spreading depolarizations with prolonged depression periods are an early indicator of delayed ischaemic brain damage after SAH. In view of experimental evidence and the present clinical results, we suggest that spreading depolarizations with prolonged depressions are a promising target for treatment development in SAH and ischaemic stroke.

  3. Long-lasting synaptic potentiation induced by depolarization under conditions that eliminate detectable Ca2+ signals.

    PubMed

    Reyes, Fredy D; Walters, Edgar T

    2010-03-01

    Activity-dependent alterations of synaptic transmission important for learning and memory are often induced by Ca(2+) signals generated by depolarization. While it is widely assumed that Ca(2+) is the essential transducer of depolarization into cellular plasticity, little effort has been made to test whether Ca(2+)-independent responses to depolarization might also induce memory-like alterations. It was recently discovered that peripheral axons of nociceptive sensory neurons in Aplysia display long-lasting hyperexcitability triggered by conditioning depolarization in the absence of Ca(2+) entry (using nominally Ca(2+)-free solutions containing EGTA, "0Ca/EGTA") or the absence of detectable Ca(2+) transients (adding BAPTA-AM, "0Ca/EGTA/BAPTA-AM"). The current study reports that depolarization of central ganglia to approximately 0 mV for 2 min in these same solutions induced hyperexcitability lasting >1 h in sensory neuron processes near their synapses onto motor neurons. Furthermore, conditioning depolarization in these solutions produced a 2.5-fold increase in excitatory postsynaptic potential (EPSP) amplitude 1-3 h afterward despite a drop in motor neuron input resistance. Depolarization in 0 Ca/EGTA produced long-term potentiation (LTP) of the EPSP lasting > or = 1 days without changing postsynaptic input resistance. When re-exposed to extracellular Ca(2+) during synaptic tests, prior exposure to 0Ca/EGTA or to 0Ca/EGTA/BAPTA-AM decreased sensory neuron survival. However, differential effects on neuronal health are unlikely to explain the observed potentiation because conditioning depolarization in these solutions did not alter survival rates. These findings suggest that unrecognized Ca(2+)-independent signals can transduce depolarization into long-lasting synaptic potentiation, perhaps contributing to persistent synaptic alterations following large, sustained depolarizations that occur during learning, neural injury, or seizures.

  4. Status epilepticus enhances tonic GABA currents and depolarizes GABA reversal potential in dentate fast-spiking basket cells

    PubMed Central

    Yu, Jiandong; Proddutur, Archana; Elgammal, Fatima S.; Ito, Takahiro

    2013-01-01

    Temporal lobe epilepsy is associated with loss of interneurons and inhibitory dysfunction in the dentate gyrus. While status epilepticus (SE) leads to changes in granule cell inhibition, whether dentate basket cells critical for regulating granule cell feedforward and feedback inhibition express tonic GABA currents (IGABA) and undergo changes in inhibition after SE is not known. We find that interneurons immunoreactive for parvalbumin in the hilar-subgranular region express GABAA receptor (GABAAR) δ-subunits, which are known to underlie tonic IGABA. Dentate fast-spiking basket cells (FS-BCs) demonstrate baseline tonic IGABA blocked by GABAAR antagonists. In morphologically and physiologically identified FS-BCs, tonic IGABA is enhanced 1 wk after pilocarpine-induced SE, despite simultaneous reduction in spontaneous inhibitory postsynaptic current (sIPSC) frequency. Amplitude of tonic IGABA in control and post-SE FS-BCs is enhanced by 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP), demonstrating the contribution of GABAAR δ-subunits. Whereas FS-BC resting membrane potential is unchanged after SE, perforated-patch recordings from FS-BCs show that the reversal potential for GABA currents (EGABA) is depolarized after SE. In model FS-BCs, increasing tonic GABA conductance decreased excitability when EGABA was shunting and increased excitability when EGABA was depolarizing. Although simulated focal afferent activation evoked seizurelike activity in model dentate networks with FS-BC tonic GABA conductance and shunting EGABA, excitability of identical networks with depolarizing FS-BC EGABA showed lower activity levels. Thus, together, post-SE changes in tonic IGABA and EGABA maintain homeostasis of FS-BC activity and limit increases in dentate excitability. These findings have implications for normal FS-BC function and can inform studies examining comorbidities and therapeutics following SE. PMID:23324316

  5. Guinea Pig Kisspeptin Neurons Are Depolarized by Leptin via Activation of TRPC Channels

    PubMed Central

    Qiu, Jian; Fang, Yuan; Bosch, Martha A.

    2011-01-01

    Hypothalamic kisspeptin neurons are critical for driving reproductive function, but virtually nothing is known about their endogenous electrophysiological properties and the effects of leptin on their excitability. Therefore, we used the slice preparation from female guinea pigs to study the endogenous conductances and the effects of leptin on kisspeptin neurons. We targeted the arcuate kisspeptin neurons using visualized-patch whole-cell recording and identified kisspeptin neurons using immuocytochemical staining for kisspeptin or single cell RT-PCR. We also harvested dispersed arcuate neurons for analysis of expression of channel transcripts. Kisspeptin neurons exhibited a relatively negative resting membrane potential, and eighty percent of the neurons expressed a pacemaker current (h-current) and a T-type Ca2+ current. Furthermore, the glutamate receptor agonist N-methyl D-aspartic acid depolarized and induced burst firing in kisspeptin neurons. Leptin activated an inward current that depolarized kisspeptin neurons and increased (burst) firing, but leptin hyperpolarized NPY neurons. Lanthanum, a TRPC-4,-5 channel activator, potentiated the leptin-induced inward current by 170%. The leptin-activated current reversed near −15 mV and was abrogated by the relatively selective TRPC channel blocker 2-APB. The leptin effects were also blocked by a Janus kinase inhibitor, a phosphatidylinositol 3 kinase inhibitor, and a phospholipase Cγ inhibitor. In addition, the majority of these neurons expressed TRPC1 and -5 and phospholipase Cγ1 based on single cell RT-PCR. Therefore, guinea pig kisspeptin neurons express endogenous pacemaker currents, and leptin excites these neurons via activation of TRPC channels. The leptin excitatory effects on kisspeptin neurons may be critical for governing the excitatory drive to GnRH neurons during different nutritional states. PMID:21285322

  6. Depolarizing Effects of Daikenchuto on Interstitial Cells of Cajal from Mouse Small Intestine

    PubMed Central

    Kim, Hyungwoo; Kim, Hyun Jung; Yang, Dongki; Jung, Myeong Ho; Kim, Byung Joo

    2017-01-01

    Background: Daikenchuto (DKT; TJ-100, TU-100), a traditional herbal medicineis used in modern medicine to treat gastrointestinal (GI) functional disorders. Interstitial cells of Cajal (ICCs) are the pacemaker cells of the GI tract and play important roles in the regulation of GI motility. Objective: The objective of this study was to investigate the effects of DKT on the pacemaker potentials (PPs) of cultured ICCs from murine small intestine. Materials and Methods: Enzymatic digestions were used to dissociate ICCs from mouse small intestine tissues. All experiments on ICCs were performed after 12 h of culture. The whole-cell patch-clamp configuration was used to record ICC PPs (current clamp mode). All experiments were performed at 30-32°C. Results: In current-clamp modeDKT depolarized and concentration-dependently decreased the amplitudes of PPs. Y25130 (a 5-HT3 receptor antagonist) or SB269970 (a 5-HT7 receptor antagonist) did not block DKT-induced PP depolarization, but RS39604 (a 5-HT4 receptor antagonist) did. Methoctramine (a muscarinic M2 receptor antagonist) failed to block DKT-induced PP depolarization, but pretreating 4-diphenylacetoxy-N-methylpiperidine methiodide (a muscarinic M3 receptor antagonist) facilitated blockade of DKT-induced PP depolarization. Pretreatment with an external Ca2+-free solution or thapsigargin abolished PPsand under these conditions, DKT did not induce PP depolarization. Furthermore Ginseng radix and Zingiberis rhizomes depolarized PPs, whereas Zanthoxyli fructus fruit (the third component of DKT) hyperpolarized PPs. Conclusion: These results suggest that DKT depolarizes ICC PPs in an internal or external Ca2+-dependent manner by stimulating 5-HT4 and M3 receptors. Furthermore, the authors suspect that the component in DKT largely responsible for depolarization is probably also a component of Ginseng radix and Zingiberis rhizomes. SUMMARY Daikenchuto (DKT) depolarized and concentration-dependently decreased the amplitudes of

  7. [Rebound depolarization of substantia gelatinosa neurons and its modulatory mechanisms in rat spinal dorsal horn].

    PubMed

    Li, Ling-Chao; Zhang, Da-Ying; Peng, Si-Cong; Wu, Jing; Jiang, Chang-Yu; Liu, Tao

    2016-02-20

    To investigate the rebound depolarization of substantia gelatinosa (SG) neurons in rat spinal dorsal horn and explore its modulatory mechanisms to provide better insights into rebound depolarization-related diseases. Parasagittal slices of the spinal cord were prepared from 3- to 5-week-old Sprague-Dawley rats. The electrophysiologic characteristics and responses to hyperpolarization stimulation were recorded using whole-cell patch-clamp technique. The effects of hyperpolarization-activated cyclic nucleotide gated cation (HCN) channel blockers and T-type calcium channel blockers on rebound depolarization of the neurons were studied. A total of 63 SG neurons were recorded. Among them, 23 neurons showed no rebound depolarization, 19 neurons showed rebound depolarization without spikes, and 21 neurons showed rebound depolarization with spikes. The action potential thresholds of the neurons without rebound depolarization were significantly higher than those of the neurons with rebound depolarization and spikes (-28.7∓1.6 mV vs -36.0∓2.0 mV, P<0.05). The two HCN channel blockers CsCl and ZD7288 significantly delayed the latency of rebound depolarization with spike from 45.9∓11.6 ms to 121.6∓51.3 ms (P<0.05) and from 36.2∓10.3 ms to 73.6∓13.6 ms (P<0.05), respectively. ZD7288 also significantly prolonged the latency of rebound depolarization without spike from 71.9∓35.1 ms to 267.0∓68.8 ms (P<0.05). The T-type calcium channel blockers NiCl2 and mibefradil strongly decreased the amplitude of rebound depolarization with spike from 19.9∓6.3 mV to 9.5∓4.5 mV (P<0.05) and from 26.1∓9.4 mV to 15.5∓5.0 mV (P<0.05), respectively. Mibefradil also significantly decreased the amplitude of rebound depolarization without spike from 14.3∓3.0 mV to 7.9∓2.0 mV (P<0.05). Nearly two-thirds of the SG neurons have rebound depolarizations modulated by HCN channel and T-type calcium channel.

  8. Faraday signature of magnetic helicity from reduced depolarization

    SciTech Connect

    Brandenburg, Axel; Stepanov, Rodion

    2014-05-10

    Using one-dimensional models, we show that a helical magnetic field with an appropriate sign of helicity can compensate the Faraday depolarization resulting from the superposition of Faraday-rotated polarization planes from a spatially extended source. For radio emission from a helical magnetic field, the polarization as a function of the square of the wavelength becomes asymmetric with respect to zero. Mathematically speaking, the resulting emission occurs then either at observable or at unobservable (imaginary) wavelengths. We demonstrate that rotation measure (RM) synthesis allows for the reconstruction of the underlying Faraday dispersion function in the former case, but not in the latter. The presence of positive magnetic helicity can thus be detected by observing positive RM in highly polarized regions in the sky and negative RM in weakly polarized regions. Conversely, negative magnetic helicity can be detected by observing negative RM in highly polarized regions and positive RM in weakly polarized regions. The simultaneous presence of two magnetic constituents with opposite signs of helicity is shown to possess signatures that can be quantified through polarization peaks at specific wavelengths and the gradient of the phase of the Faraday dispersion function. Similar polarization peaks can tentatively also be identified for the bi-helical magnetic fields that are generated self-consistently by a dynamo from helically forced turbulence, even though the magnetic energy spectrum is then continuous. Finally, we discuss the possibility of detecting magnetic fields with helical and non-helical properties in external galaxies using the Square Kilometre Array.

  9. Pulsing Depolarization: New Method of In-Vivo Blood Glucometry

    NASA Astrophysics Data System (ADS)

    Romanov, Dmitri; Shvartsman, Leonid; Fine, Ilya

    2002-03-01

    We propose a new system of non-invasive measurements enabling one to monitor in-vivo the glucose content of the blood. The proposed method is based on the transmission oximetry technique [1] and on the model of red blood cell aggregation [2]. We utilize the known birefregence of glucose solutions (in this case, the blood plasma) and the absence of this optical activity on the part of the red cells. Thus, we model the blood as a birefrigent host medium filled with optically non-active inclusions of spheroidal shape, arbitrarily oriented and having one semiaxis growing with time during the cell aggregation. We trace the evolution of initially linearly polarized laser beam in this system, and calculate the ellipticity and the azimuthal angle of the resulting partially depolarized light. The azimuthal angle is obtained as time-independent quantity being a function of the hematocrit, glucose content and thickness of the host medium layer, while the ellipticity depends also on the red cell aggregation, and thus oscillates with the heartbeats. Measurements of both the azimuthal angle and the ellipticity provide us with sufficient data to determine the glucose content of the blood. [1] I. Fine, A. Weinreb, Med. and Biol. Eng. and Comput., 31, 516 (1993). [2] L.D. Shvartsman, I. Fine, SPIE Proc., 4162, 120 (2000).

  10. Mitochondrial activity and brain functions during cortical depolarization

    NASA Astrophysics Data System (ADS)

    Mayevsky, Avraham; Sonn, Judith

    2008-12-01

    Cortical depolarization (CD) of the cerebral cortex could be developed under various pathophysiological conditions. In animal models, CD was recorded under partial or complete ischemia as well as when cortical spreading depression (SD) was induced externally or by internal stimulus. The development of CD in patients and the changes in various metabolic parameters, during CD, was rarely reported. Brain metabolic, hemodynamic, ionic and electrical responses to the CD event are dependent upon the O2 balance in the tissue. When the O2 balance is negative (i.e. ischemia), the CD process will be developed due to mitochondrial dysfunction, lack of energy and the inhibition of Na+-K+-ATPase. In contradiction, when oxygen is available (i.e. normoxia) the development of CD after induction of SD will accelerate mitochondrial respiration for retaining ionic homeostasis and normal brain functions. We used the multiparametric monitoring approach that enable real time monitoring of mitochondrial NADH redox state, microcirculatory blood flow and oxygenation, extracellular K+, Ca2+, H+ levels, DC steady potential and electrocorticogram (ECoG). This monitoring approach, provide a unique tool that has a significant value in analyzing the pathophysiology of the brain when SD developed under normoxia, ischemia, or hypoxia. We applied the same monitoring approach to patients suffered from severe head injury or exposed to neurosurgical procedures.

  11. Numerical determination of lateral loss coefficients for subchannel analysis in nuclear fuel bundles

    SciTech Connect

    Sin Kim; Goon-Cherl Park

    1995-09-01

    An accurate prediction of cross-flow based on detailed knowledge of the velocity field in subchannels of a nuclear fuel assembly is of importance in nuclear fuel performance analysis. In this study, the low-Reynolds number {kappa}-{epsilon} turbulence model has been adopted in two adjacent subchannels with cross-flow. The secondary flow is estimated accurately by the anisotropic algebraic Reynolds stress model. This model was numerically calculated by the finite element method and has been verified successfully through comparison with existing experimental data. Finally, with the numerical analysis of the velocity field in such subchannel domain, an analytical correlation of the lateral loss coefficient is obtained to predict the cross-flow rate in subchannel analysis codes. The correlation is expressed as a function of the ratio of the lateral flow velocity to the donor subchannel axial velocity, recipient channel Reynolds number and pitch-to-diameter.

  12. Numerical power balance and free energy loss analysis for solar cells including optical, thermodynamic, and electrical aspects

    SciTech Connect

    Greulich, Johannes Höffler, Hannes; Würfel, Uli; Rein, Stefan

    2013-11-28

    A method for analyzing the power losses of solar cells is presented, supplying a complete balance of the incident power, the optical, thermodynamic, and electrical power losses and the electrical output power. The involved quantities have the dimension of a power density (units: W/m{sup 2}), which permits their direct comparison. In order to avoid the over-representation of losses arising from the ultraviolet part of the solar spectrum, a method for the analysis of the electrical free energy losses is extended to include optical losses. This extended analysis does not focus on the incident solar power of, e.g., 1000 W/m{sup 2} and does not explicitly include the thermalization losses and losses due to the generation of entropy. Instead, the usable power, i.e., the free energy or electro-chemical potential of the electron-hole pairs is set as reference value, thereby, overcoming the ambiguities of the power balance. Both methods, the power balance and the free energy loss analysis, are carried out exemplarily for a monocrystalline p-type silicon metal wrap through solar cell with passivated emitter and rear (MWT-PERC) based on optical and electrical measurements and numerical modeling. The methods give interesting insights in photovoltaic (PV) energy conversion, provide quantitative analyses of all loss mechanisms, and supply the basis for the systematic technological improvement of the device.

  13. [The correlation analysis of coagulation detection and blood routine parameters of sudden hearing loss].

    PubMed

    Bao, Fengxiang; Zhang, Shujia; Zhang, Yanping; Zhu, Xuetao; Liu, Weiwei

    2015-01-01

    Through the analysis of coagulation convention and blood routine parameters of sudden hearing loss (SHL) patients, further prove the correlation of sudden deafness and the the inner ear microcirculation, to guide clinical diagnosis and treatment. Select 424 patients (448 ears) with sudden deafness in our department to SHL group. According to hearing curve is classified into low intermediate frequency descent group, high frequency drop and full frequency group, and drawing 244 cases in the same period of hospitalization deviated septum, vocal cord polyp patients as control group. All patients' coagulation detection, D-dimer, blood leukocytes, neutrophils and platelet count percentages were analyzed. Then a meaningful factor multivariate Logistic regression analysis was made. There was a statistically significant difference between the two groups' prothrombin time, international normalized ratio, activated partial thromboplastin time, thrombin time measurement, fibrinogen, D-dimer, platelet count, white blood cell, neutrophil ratio(P<0.05); Logistic regression analysis showed that the prothrombin, thrombin time measurement, fibrinogen, D-dimer, neutrophil incidence of sudden hearing loss associated risk factors. SHL in patients with coagulation dysfunction may be involved in the occurrence of SHL development mechanism, and there is a correlation of the SHL and the dysfunction of inner ear microcirculation.

  14. Tranexamic acid decreases blood loss in shoulder arthroplasty: A meta-analysis.

    PubMed

    Yu, Bin-Feng; Yang, Guo-Jing; Li, Qi; Liu, Liang-le

    2017-08-01

    The objective of this meta-analysis was to evaluate the efficacy and safety of tranexamic acid (TXA) in shoulder arthroplasty (SA). Academic articles were identified from the Cochrane Library, Medline (1966-2017.2), PubMed (1966-2017.2), Embase (1980-2017.2), and ScienceDirect (1966-2017.2). Randomized controlled trials (RCTs) and non-RCTs studying TXA in SA were included. Two independent reviewers conducted independent data abstraction. The I statistic was used to assess heterogeneity. Fixed- or random-effects models were used for meta-analysis. Two RCTs and 2 non-RCTs met the inclusion criteria. This meta-analysis found significant differences in postoperative hemoglobin reduction (MD = -0.71 g/dL), drainage volume (MD = -133.21 mL), and total blood loss (MD = -226.82 mL) between TXA groups and controls. There were no significant differences in blood transfusion requirements, operation time, or length of hospital stay. The use of TXA in SA decreases postoperative hemoglobin reduction, drainage volume, and total blood loss and does not increase the risk of complications. Because of the limited high-quality evidence currently available, additional randomized controlled trials are required.

  15. Efficacy and safety of topiramate on weight loss: a meta-analysis of randomized controlled trials.

    PubMed

    Kramer, C K; Leitão, C B; Pinto, L C; Canani, L H; Azevedo, M J; Gross, J L

    2011-05-01

    Topiramate was associated with weight loss in clinical trials. We summarize the evidence on the efficacy and safety of topiramate in the treatment of overweight/obesity. The databases Medline, Embase, and Cochrane were searched. Randomized controlled studies with at least 16 weeks of duration that report the effect of topiramate on weight loss and adverse events were eligible for inclusion. Ten studies were included (3320 individuals). Patients treated with topiramate lost an average of 5.34 kg (95% confidence interval [95%CI]-6.12 to -4.56) of additional weight as compared with placebo. According to meta-regression analysis, treatment duration and dosage were associated with the efficacy of topiramate treatment. Evaluating trials using topiramate 96-200 mg day(-1) , the weight loss was higher in trials with >28 weeks of duration (-6.58 kg [95%CI -7.48 to -5.68]) than in trials with ≤28 weeks (-4.11 kg [95%CI -4.92 to -3.30]). Data of 6620 individuals were available for adverse events evaluation and those more frequently observed were paraesthesia, taste impairment and psychomotor disturbances. The odds ratio for adverse events leading to topiramate withdrawal was 1.94 (95%CI 1.64-2.29) compared with the control group. In conclusion, topiramate might be a useful adjunctive therapeutic tool in the treatment of obesity as long as proper warnings about side effects are considered.

  16. Characterization of impulse noise and hazard analysis of impulse noise induced hearing loss using AHAAH modeling

    NASA Astrophysics Data System (ADS)

    Wu, Qing

    Millions of people across the world are suffering from noise induced hearing loss (NIHL), especially under working conditions of either continuous Gaussian or non-Gaussian noise that might affect human's hearing function. Impulse noise is a typical non-Gaussian noise exposure in military and industry, and generates severe hearing loss problem. This study mainly focuses on characterization of impulse noise using digital signal analysis method and prediction of the auditory hazard of impulse noise induced hearing loss by the Auditory Hazard Assessment Algorithm for Humans (AHAAH) modeling. A digital noise exposure system has been developed to produce impulse noises with peak sound pressure level (SPL) up to 160 dB. The characterization of impulse noise generated by the system has been investigated and analyzed in both time and frequency domains. Furthermore, the effects of key parameters of impulse noise on auditory risk unit (ARU) are investigated using both simulated and experimental measured impulse noise signals in the AHAAH model. The results showed that the ARUs increased monotonically with the peak pressure (both P+ and P-) increasing. With increasing of the time duration, the ARUs increased first and then decreased, and the peak of ARUs appeared at about t = 0.2 ms (for both t+ and t-). In addition, the auditory hazard of experimental measured impulse noises signals demonstrated a monotonically increasing relationship between ARUs and system voltages.

  17. Proteomic analysis of pRb loss highlights a signature of decreased mitochondrial oxidative phosphorylation

    PubMed Central

    Nicolay, Brandon N.; Danielian, Paul S.; Kottakis, Filippos; Lapek, John D.; Sanidas, Ioannis; Miles, Wayne O.; Dehnad, Mantre; Tschöp, Katrin; Gierut, Jessica J.; Manning, Amity L.; Morris, Robert; Haigis, Kevin; Bardeesy, Nabeel; Lees, Jacqueline A.; Haas, Wilhelm; Dyson, Nicholas J.

    2015-01-01

    The retinoblastoma tumor suppressor (pRb) protein associates with chromatin and regulates gene expression. Numerous studies have identified Rb-dependent RNA signatures, but the proteomic effects of Rb loss are largely unexplored. We acutely ablated Rb in adult mice and conducted a quantitative analysis of RNA and proteomic changes in the colon and lungs, where RbKO was sufficient or insufficient to induce ectopic proliferation, respectively. As expected, RbKO caused similar increases in classic pRb/E2F-regulated transcripts in both tissues, but, unexpectedly, their protein products increased only in the colon, consistent with its increased proliferative index. Thus, these protein changes induced by Rb loss are coupled with proliferation but uncoupled from transcription. The proteomic changes in common between RbKO tissues showed a striking decrease in proteins with mitochondrial functions. Accordingly, RB1 inactivation in human cells decreased both mitochondrial mass and oxidative phosphorylation (OXPHOS) function. RBKO cells showed decreased mitochondrial respiratory capacity and the accumulation of hypopolarized mitochondria. Additionally, RB/Rb loss altered mitochondrial pyruvate oxidation from 13C-glucose through the TCA cycle in mouse tissues and cultured cells. Consequently, RBKO cells have an enhanced sensitivity to mitochondrial stress conditions. In summary, proteomic analyses provide a new perspective on Rb/RB1 mutation, highlighting the importance of pRb for mitochondrial function and suggesting vulnerabilities for treatment. PMID:26314710

  18. Analysis of the relationship between cognitive skills and unilateral sensory hearing loss.

    PubMed

    Calderón-Leyva, I; Díaz-Leines, S; Arch-Tirado, E; Lino-González, A L

    2016-07-21

    To analyse cognitive skills in patients with severe unilateral hearing loss versus those in subjects with normal hearing. 40 adults participated: 20 patients (10 women and 10 men) with severe unilateral hearing loss and 20 healthy subjects matched to the study group. Cognitive abilities were measured with the Spanish version of the Woodcock Johnson Battery-Revised; central auditory processing was assessed with monaural psychoacoustic tests. Box plots were drawn and t tests were performed for samples with a significance of P≤.05. A comparison of performances on the filtered word testing and time-compressed disyllabic word tests between patients and controls revealed a statistically significant difference (P≤.05) with greater variability among responses by hearing impaired subjects. This same group also showed a better cognitive performance on the numbers reversed, visual auditory learning, analysis synthesis, concept formation, and incomplete words tests. Patients with hearing loss performed more poorly than controls on the filtered word and time-compressed disyllabic word tests, but more competently on memory, reasoning, and auditory processing tasks. Complementary tests, such as those assessing central auditory processes and cognitive ability tests, are important and helpful for designing habilitation/rehabilitation and therapeutic strategies intended to optimise and stimulate cognitive skills in subjects with unilateral hearing impairment. Copyright © 2016 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  19. Optoelectronic Evaluation and Loss Analysis of PEDOT:PSS/Si Hybrid Heterojunction Solar Cells.

    PubMed

    Yang, Zhenhai; Fang, Zebo; Sheng, Jiang; Ling, Zhaoheng; Liu, Zhaolang; Zhu, Juye; Gao, Pingqi; Ye, Jichun

    2017-12-01

    The organic/silicon (Si) hybrid heterojunction solar cells (HHSCs) have attracted considerable attention due to their potential advantages in high efficiency and low cost. However, as a newly arisen photovoltaic device, its current efficiency is still much worse than commercially available Si solar cells. Therefore, a comprehensive and systematical optoelectronic evaluation and loss analysis on this HHSC is therefore highly necessary to fully explore its efficiency potential. Here, a thoroughly optoelectronic simulation is provided on a typical planar polymer poly (3,4-ethylenedioxy thiophene):polystyrenesulfonate (PEDOT:PSS)/Si HHSC. The calculated spectra of reflection and external quantum efficiency (EQE) match well with the experimental results in a full-wavelength range. The losses in current density, which are contributed by both optical losses (i.e., reflection, electrode shield, and parasitic absorption) and electrical recombination (i.e., the bulk and surface recombination), are predicted via carefully addressing the electromagnetic and carrier-transport processes. In addition, the effects of Si doping concentrations and rear surface recombination velocities on the device performance are fully investigated. The results drawn in this study are beneficial to the guidance of designing high-performance PEDOT:PSS/Si HHSCs.

  20. Optoelectronic Evaluation and Loss Analysis of PEDOT:PSS/Si Hybrid Heterojunction Solar Cells

    NASA Astrophysics Data System (ADS)

    Yang, Zhenhai; Fang, Zebo; Sheng, Jiang; Ling, Zhaoheng; Liu, Zhaolang; Zhu, Juye; Gao, Pingqi; Ye, Jichun

    2017-01-01

    The organic/silicon (Si) hybrid heterojunction solar cells (HHSCs) have attracted considerable attention due to their potential advantages in high efficiency and low cost. However, as a newly arisen photovoltaic device, its current efficiency is still much worse than commercially available Si solar cells. Therefore, a comprehensive and systematical optoelectronic evaluation and loss analysis on this HHSC is therefore highly necessary to fully explore its efficiency potential. Here, a thoroughly optoelectronic simulation is provided on a typical planar polymer poly (3,4-ethylenedioxy thiophene):polystyrenesulfonate (PEDOT:PSS)/Si HHSC. The calculated spectra of reflection and external quantum efficiency (EQE) match well with the experimental results in a full-wavelength range. The losses in current density, which are contributed by both optical losses (i.e., reflection, electrode shield, and parasitic absorption) and electrical recombination (i.e., the bulk and surface recombination), are predicted via carefully addressing the electromagnetic and carrier-transport processes. In addition, the effects of Si doping concentrations and rear surface recombination velocities on the device performance are fully investigated. The results drawn in this study are beneficial to the guidance of designing high-performance PEDOT:PSS/Si HHSCs.

  1. Analysis of ECLSS performance during reentry after loss of one ammonia tank

    NASA Technical Reports Server (NTRS)

    Steines, G. J.

    1976-01-01

    An analysis was performed to determine whether, in case of a loss of one of the ammonia tanks, the Ammonia Boiler System can provide adequate heat rejection for the orbiter ECLSS during reentry. Results indicate that temperatures can be maintained as long as NH3 is available, but that one tank does not contain sufficient NH3 to complete all missions. A recommendation is made to investigate incorporation of onboard NH3 quantity calculations, and/or addition of a third NH3 tank.

  2. Considerations to prevent the breakdown and loss of fruit carotenoids during extraction and analysis in Musa.

    PubMed

    Davey, Mark W; Mellidou, Ifigeneia; Keulemans, Wannes

    2009-07-24

    The impact of treatments aimed at improving the robustness of protocols for the analysis of carotenoids in fruit of banana and plantain were examined. Neither the inclusion of polyvinylpolypyrrolidine in the extraction buffer, nor vigorous homogenisation with glass beads influenced recoveries or chromatographic profiles. By contrast, heating lead to losses of up to 53% and to the formation of degradation products that are no longer detectable on our RP-HPLC system. Carotenoid extracts are unstable and most sensitive to exposure to light. However, even in the dark at -20 degrees C and in the presence of antioxidants breakdown rates of around 5% per day were observed.

  3. Popular Mobile Phone Apps for Diet and Weight Loss: A Content Analysis

    PubMed Central

    Roehrer, Erin

    2016-01-01

    Background A review of the literature has revealed that the rates of overweight and obesity have been increasing in Australia over the last two decades and that wellness mobile phone apps play a significant role in monitoring and managing individuals’ weight. Although mobile phone app markets (iTunes and Google Play) list thousands of mobile phone health apps, it is not always clear whether those apps are supported by credible sources. Likewise, despite the prevailing use of mobile phone apps to aid with weight management, the usability features of these apps are not well characterized. Objective The research explored how usability taxonomy could inform the popularity of downloaded, socially focused wellness mobile phone apps, in particular weight loss and diet apps. The aim of the study was to investigate the Australian mobile phone app stores (iTunes and Google Play) in order to examine the usability features of the most popular (ie, most downloaded) wellness apps. Methods The design of this study comprises 3 main stages: stage 1, identifying apps; stage 2, development of weight loss and diet evaluation framework; and stage 3, application of the evaluation framework. Each stage includes specific data collection, analysis tools, and techniques. Results The study has resulted in the development of a justified evaluation framework for weight loss and diet mobile phone apps. Applying the evaluation framework to the identified apps has shown that the most downloaded iTunes and Google Play apps are not necessarily the most usable or effective. In addition, the research found that search algorithms for iTunes and Google Play are biased toward apps’ titles and keywords that do not accurately define the real functionality of the app. Moreover, the study has also analyzed the apps’ user reviews, which served as justification for the developed evaluation framework. Conclusions The analysis has shown that ease of use, reminder, bar code scanning, motivation, usable for

  4. Popular Mobile Phone Apps for Diet and Weight Loss: A Content Analysis.

    PubMed

    Zaidan, Sarah; Roehrer, Erin

    2016-07-11

    A review of the literature has revealed that the rates of overweight and obesity have been increasing in Australia over the last two decades and that wellness mobile phone apps play a significant role in monitoring and managing individuals' weight. Although mobile phone app markets (iTunes and Google Play) list thousands of mobile phone health apps, it is not always clear whether those apps are supported by credible sources. Likewise, despite the prevailing use of mobile phone apps to aid with weight management, the usability features of these apps are not well characterized. The research explored how usability taxonomy could inform the popularity of downloaded, socially focused wellness mobile phone apps, in particular weight loss and diet apps. The aim of the study was to investigate the Australian mobile phone app stores (iTunes and Google Play) in order to examine the usability features of the most popular (ie, most downloaded) wellness apps. The design of this study comprises 3 main stages: stage 1, identifying apps; stage 2, development of weight loss and diet evaluation framework; and stage 3, application of the evaluation framework. Each stage includes specific data collection, analysis tools, and techniques. The study has resulted in the development of a justified evaluation framework for weight loss and diet mobile phone apps. Applying the evaluation framework to the identified apps has shown that the most downloaded iTunes and Google Play apps are not necessarily the most usable or effective. In addition, the research found that search algorithms for iTunes and Google Play are biased toward apps' titles and keywords that do not accurately define the real functionality of the app. Moreover, the study has also analyzed the apps' user reviews, which served as justification for the developed evaluation framework. The analysis has shown that ease of use, reminder, bar code scanning, motivation, usable for all, and synchronization are significant attributes

  5. Arrests, Recent Life Circumstances, and Recurrent Job Loss for At-Risk Young Men: An Event-History Analysis

    ERIC Educational Resources Information Center

    Wiesner, Margit; Capaldi, Deborah M.; Kim, Hyoun K.

    2010-01-01

    This study used longitudinal data from 202 at-risk young men to examine effects of arrests, prior risk factors, and recent life circumstances on job loss across a 7-year period in early adulthood. Repeated failure-time continuous event-history analysis indicated that occurrence of job loss was primarily related to prior mental health problems,…

  6. Solar power generation by use of Stirling engine and heat loss analysis of its cavity receiver

    NASA Astrophysics Data System (ADS)

    Hussain, Tassawar

    position (AP=H/D) were used to characterize the different configurations of Cavity Receiver and it was found that the Cavity Receiver with AR=0.5 and AP=0.53 has the maximum capability to utilize the solar heat to attain the maximum temperature of the heat pipe receiver. Experimental heat loss analysis at low temperature for different configurations of the cavity receiver was performed and air film temperature profiles along the wall height (H) of the cavity receiver were determined. Since sodium heat pipes operate at high temperature (973K), there are huge possibilities of radiation and convection heat losses for direct solar heating of the heater head. Therefore mathematical modeling of heat loss analysis and its numerical solution at high temperature was also included in the research objectives. 2-D axisymmetric model with weakly compressible Navier Stokes equation and general heat conduction and convection equations were simultaneously solved using the finite element method approach. Computational fluid dynamics package COMSOL 3.5a was used as a numerical tool. The temperature, and flow field pattern inside the cavity receiver were also visualized by means of surface contours. Heat loss analysis were performed for different configurations of Cavity Receiver and the numerical solution of different configuration showed that the aperture ratio (AR) plays a significant role for convection and radiation heat losses whereas the aperture position (AP) effects are negligible.

  7. The continuum of spreading depolarizations in acute cortical lesion development: Examining Leão's legacy.

    PubMed

    Hartings, Jed A; Shuttleworth, C William; Kirov, Sergei A; Ayata, Cenk; Hinzman, Jason M; Foreman, Brandon; Andrew, R David; Boutelle, Martyn G; Brennan, K C; Carlson, Andrew P; Dahlem, Markus A; Drenckhahn, Christoph; Dohmen, Christian; Fabricius, Martin; Farkas, Eszter; Feuerstein, Delphine; Graf, Rudolf; Helbok, Raimund; Lauritzen, Martin; Major, Sebastian; Oliveira-Ferreira, Ana I; Richter, Frank; Rosenthal, Eric S; Sakowitz, Oliver W; Sánchez-Porras, Renán; Santos, Edgar; Schöll, Michael; Strong, Anthony J; Urbach, Anja; Westover, M Brandon; Winkler, Maren Kl; Witte, Otto W; Woitzik, Johannes; Dreier, Jens P

    2016-01-01

    A modern understanding of how cerebral cortical lesions develop after acute brain injury is based on Aristides Leão's historic discoveries of spreading depression and asphyxial/anoxic depolarization. Treated as separate entities for decades, we now appreciate that these events define a continuum of spreading mass depolarizations, a concept that is central to understanding their pathologic effects. Within minutes of acute severe ischemia, the onset of persistent depolarization triggers the breakdown of ion homeostasis and development of cytotoxic edema. These persistent changes are diagnosed as diffusion restriction in magnetic resonance imaging and define the ischemic core. In delayed lesion growth, transient spreading depolarizations arise spontaneously in the ischemic penumbra and induce further persistent depolarization and excitotoxic damage, progressively expanding the ischemic core. The causal role of these waves in lesion development has been proven by real-time monitoring of electrophysiology, blood flow, and cytotoxic edema. The spreading depolarization continuum further applies to other models of acute cortical lesions, suggesting that it is a universal principle of cortical lesion development. These pathophysiologic concepts establish a working hypothesis for translation to human disease, where complex patterns of depolarizations are observed in acute brain injury and appear to mediate and signal ongoing secondary damage.

  8. Octopus cells of the mammalian ventral cochlear nucleus sense the rate of depolarization.

    PubMed

    Ferragamo, Michael J; Oertel, Donata

    2002-05-01

    Whole cell patch recordings in slices show that the probability of firing of action potentials in octopus cells of the ventral cochlear nucleus depends on the dynamic properties of depolarization. Octopus cells fired only when the rate of rise of a depolarization exceeded a threshold value that varied between 5 and 15 mV/ms among cells. The threshold rate of rise was independent of whether depolarizations were evoked synaptically or by the intracellular injection of current. Previous work showed that octopus cells are contacted by many auditory nerve fibers, each providing less than 1-mV depolarization. Summation of synaptic input from multiple fibers is required for an octopus cell to reach threshold. In firing only when synaptic depolarization exceeds a threshold rate, octopus cells fire selectively when synaptic input is sufficiently large and synchronized for the small, brief unitary excitatory postsynaptic potentials (EPSPs) to sum to produce a rapidly rising depolarization. The sensitivity to rate of depolarization is governed by a low-threshold, alpha-dendrotoxin-sensitive potassium conductance (g(KL)). This conductance also shapes the peaks of action potentials, contributing to the precision in their timing. Firing in neighboring T stellate cells depends much less strongly on the rate of rise. They lack strong alpha-dendrotoxin-sensitive conductances. Octopus cells appear to be specialized to detect synchronization in the activation of groups of auditory nerve fibers, a common pattern in responses to natural sounds, and convey its occurrence with temporal precision.

  9. Repetitive Transient Depolarizations of the Inner Mitochondrial Membrane Induced by Proton Pumping

    PubMed Central

    Hattori, Tomohiro; Watanabe, Koichi; Uechi, Yukiko; Yoshioka, Hisashi; Ohta, Yoshihiro

    2005-01-01

    Single mitochondria show the spontaneous fluctuations of ΔΨm. In this study, to examine the mechanism of the fluctuations, we observed ΔΨm in single isolated heart mitochondria using time-resolved fluorescence microscopy. Addition of malate, succinate, or ascorbate plus TMPD to mitochondria induced polarization of the inner membrane followed by repeated cycles of rapid depolarizations and immediate repolarizations. ADP significantly decreased the frequency of the rapid depolarizations, but the ADP effect was counteracted by oligomycin. On the other hand, the rapid depolarizations did not occur when mitochondria were polarized by the efflux of K+ from the matrix. The rapid depolarizations became frequent with the increase in the substrate concentration or pH of the buffer. These results suggest that the rapid depolarizations depend on the net translocation of protons from the matrix. The frequency of the rapid depolarizations was not affected by ROS scavengers, Ca2+, CsA, or BA. In addition, the obvious increase in the permeability of the inner membrane to calcein (MW 623) that was entrapped in the matrix was not observed upon the transient depolarization. The mechanisms of the spontaneous oscillations of ΔΨm are discussed in relation to the matrix pH and the permeability transitions. PMID:15653749

  10. Depolarization of Cellular Resting Membrane Potential Promotes Neonatal Cardiomyocyte Proliferation In Vitro

    PubMed Central

    Lan, Jen-Yu; Williams, Corin; Levin, Michael; Black, Lauren Deems

    2014-01-01

    Cardiomyocytes (CMs) undergo a rapid transition from hyperplastic to hypertrophic growth soon after birth, which is a major challenge to the development of engineered cardiac tissue for pediatric patients. Resting membrane potential (Vmem) has been shown to play an important role in cell differentiation and proliferation during development. We hypothesized that depolarization of neonatal CMs would stimulate or maintain CM proliferation in vitro. To test our hypothesis, we isolated postnatal day 3 neonatal rat CMs and subjected them to sustained depolarization via the addition of potassium gluconate or Ouabain to the culture medium. Cell density and CM percentage measurements demonstrated an increase in mitotic CMs along with a ~2 fold increase in CM numbers with depolarization. In addition, depolarization led to an increase in cells in G2 and S phase, indicating increased proliferation, as measured by flow cytometry. Surprisingly depolarization of Vmem with either treatment led to inhibition of proliferation in cardiac fibroblasts. This effect is abrogated when the study was carried out on postnatal day 7 neonatal CMs, which are less proliferative, indicating that the likely mechanism of depolarization is the maintenance of the proliferating CM population. In summary, our findings suggest that depolarization maintains postnatal CM proliferation and may be a novel approach to encourage growth of engineered tissue and cardiac regeneration in pediatric patients. PMID:25295125

  11. Redox-active nanoceria depolarize mitochondrial membrane of human colon cancer cells

    NASA Astrophysics Data System (ADS)

    Jana, Saikat Kumar; Banerjee, Priyanka; Das, Soumen; Seal, Sudipta; Chaudhury, Koel

    2014-06-01

    Nanotherapeutics is emerging as a promising option to the various limitations and side effects associated with conventional chemotherapy. The present study investigates the cytotoxic effect of redox-active cerium oxide nanoparticles (nanoceria) on human colorectal adenocarcinoma-derived cell line (HCT 15). Exposure of these cells to nanoceria for 24 h with concentration ranging between 10 and 100 μM resulted in a significant reduction of cell viability in a dose-dependent manner. Further, at a concentration of 10 µM, nanoceria exhibited time-dependent cytotoxic effect when exposed to the cells for 24, 48, and 72 h. Upon treatment of the cells with nanoceria, reactive oxygen species (ROS) and lipid peroxidation which are indicators of oxidative stress and cytotoxicity increased significantly, in a dose-dependent manner. Nanoceria was also found to depolarize the mitochondrial membrane, thereby collapsing the membrane potential and leading to initiation of apoptosis. Scanning electron microscopic study of nanoceria-treated HCT 15 cells showed morphological changes and loss of filopodia and lamellipodia, indicating arrest of metastatic spread. Summarizing, when cultured HCT 15 cells are exposed to nanoceria, a dose-dependent cytotoxic effect mediated by ROS generation is observed.

  12. Photo-elastic effect, thermal lensing and depolarization in a-cut tetragonal laser crystals

    NASA Astrophysics Data System (ADS)

    Yumashev, K. V.; Zakharova, A. N.; Loiko, P. A.

    2016-06-01

    We report on analytical description of thermal lensing effect in tetragonal crystals cut along the [1 0 0] crystallographic axis, for the two principal light polarizations, E ┴ c and E || c, under diode-pumping (plane stress approximation). Within this approach, we take into account anisotropy of elastic, photo-elastic, thermal and optical properties of the material. Expressions for the ‘generalized’ thermo-optic coefficient χ are presented. It is shown that astigmatism of thermal lens is determined both by the photo-elastic and end-bulging effects. The sign of the photo-elastic term χ″ can be either positive or negative affecting significantly the sign of the thermal lens. Depolarization loss in a-cut tetragonal crystals is few orders of magnitude lower than that in cubic crystals. Calculations are performed for a-cut tetragonal molybdates, Nd:CaMoO4, Nd:PbMoO4 and Nd:NaBi(MoO4)2.

  13. Aircraft Loss-of-Control: Analysis and Requirements for Future Safety-Critical Systems and Their Validation

    NASA Technical Reports Server (NTRS)

    Belcastro, Christine M.

    2011-01-01

    Loss of control remains one of the largest contributors to fatal aircraft accidents worldwide. Aircraft loss-of-control accidents are complex, resulting from numerous causal and contributing factors acting alone or more often in combination. Hence, there is no single intervention strategy to prevent these accidents. This paper summarizes recent analysis results in identifying worst-case combinations of loss-of-control accident precursors and their time sequences, a holistic approach to preventing loss-of-control accidents in the future, and key requirements for validating the associated technologies.

  14. Depolarization due to beam-beam interaction in electron-positron linear colliders

    SciTech Connect

    Yokoya, K. ); Chen, P. )

    1989-05-05

    We investigate two major mechanisms which induce depolarization of electron beams during beam-beam interaction in linear colliders. These are the classical spin precession under the collective field of the oncoming beam, and the spin-flip effect from beamstrahlung. Analytic formulas are derived for estimating these depolarization effects. As examples, we estimate the depolarization in the Stanford Linear Collider (SLC) and a possible future TeV linear collider (TLC). The effects are found to be negligibly small for SLC and not very large for TLC.

  15. Depolarization due to beam-beam interaction in electron-positron linear colliders

    SciTech Connect

    Yokoya, Kaoru; Chen, Pisin

    1988-09-01

    We investigate two major mechanisms which induce depolarization of electron beams during beam-beam interaction in linear colliders. These are the classical spin precession under the collective field of the oncoming beam, and the spin-flip effect from beamstrahlung. Analytic formulas are derived for estimating these depolarization effects. As examples, we estimate the depolarization in the Stanford Linear Collider (SLC) and a possible future TeV linear collider (TLC). The effects are found to be negligibly small for SLC and not very large for TLC. 7 refs., 1 fig.

  16. Longitudinal polarization periodicity of unpolarized light passing through a double wedge depolarizer.

    PubMed

    de Sande, Juan Carlos G; Santarsiero, Massimo; Piquero, Gemma; Gori, Franco

    2012-12-03

    The polarization characteristics of unpolarized light passing through a double wedge depolarizer are studied. It is found that the degree of polarization of the radiation propagating after the depolarizer is uniform across transverse planes after the depolarizer, but it changes from one plane to another in a periodic way giving, at different distances, unpolarized, partially polarized, or even perfectly polarized light. An experiment is performed to confirm this result. Measured values of the Stokes parameters and of the degree of polarization are in complete agreement with the theoretical predictions.

  17. Statistical meaning of the differential Mueller matrix of depolarizing homogeneous media.

    PubMed

    Ossikovski, Razvigor; Arteaga, Oriol

    2014-08-01

    By applying the statistical definition of a depolarizing Mueller matrix we formally derive and physically interpret the differential matrix of a depolarizing homogeneous medium. The depolarization phenomenon being a direct consequence of the fluctuations of the six elementary polarization properties of the medium, the differential matrix contains the mean values and the variances of the properties, thus fully describing those from a statistical viewpoint. Similarly, the reduced coherency matrix associated with the G-symmetric component of the differential matrix has an immediate physical interpretation as being the covariance matrix of the three basic groups of polarization properties. The formal developments are illustrated on experimental examples.

  18. Characterization of homogenous depolarizing media based on Mueller matrix differential decomposition.

    PubMed

    Arteaga, Oriol; Kahr, Bart

    2013-04-01

    In a depolarizing medium in which the optical properties are uniformly distributed, the logarithm of the Mueller matrix can be used to calculate the differential Mueller matrix. From the differential Mueller matrix, the 10 optical properties of a homogeneous depolarizing medium are recovered. A modified calculation is introduced for media showing small time-irreversal depolarization events. The benefits of this method are illustrated in the determination of circular dichroism and circular birefringence of a nickel sulfate hexahydrate crystal from spectroscopic Mueller matrix measurements.

  19. Modulation of electromagnetic fields by a depolarizer of random polarizer array.

    PubMed

    Ma, Ning; Hanson, Steen G; Wang, Wei

    2016-05-01

    The statistical properties of the electric fields with random changes of the polarization state in space generated by a depolarizer are investigated on the basis of the coherence matrix. The depolarizer is a polarizer array composed of a multitude of contiguous square cells of polarizers with randomly distributed polarization angles, where the incident fields experience a random polarization modulation after passing through the depolarizer. The propagation of the modulated electric fields through any quadratic optical system is examined within the framework of the complex ABCD matrix to show how the degree of coherence and the degree of polarization change on propagation.

  20. Analysis of Loss-of-Offsite-Power Events 1998–2013

    SciTech Connect

    Schroeder, John Alton

    2015-02-01

    Loss of offsite power (LOOP) can have a major negative impact on a power plant’s ability to achieve and maintain safe shutdown conditions. Risk analyses suggest that loss of all alternating current power contributes over 70% of the overall risk at some U.S. nuclear plants. LOOP event and subsequent restoration of offsite power are important inputs to plant probabilistic risk assessments. This report presents a statistical and engineering analysis of LOOP frequencies and durations at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience during calendar years 1997 through 2013. Frequencies and durations were determined for four event categories: plant-centered, switchyard-centered, grid-related, and weather-related. The emergency diesel generator failure modes considered are failure to start, failure to load and run, and failure to run more than 1 hour. The component reliability estimates and the reliability data are trended for the most recent 10-year period while yearly estimates for reliability are provided for the entire active period. No statistically significant trends in LOOP frequencies over the 1997–2013 period are identified. There is a possibility that a significant trend in grid-related LOOP frequency exists that is not easily detected by a simple analysis. Statistically significant increases in recovery times after grid- and switchyard-related LOOPs are identified.

  1. Analysis of a compartmental model of amyloid beta production, irreversible loss and exchange in humans.

    PubMed

    Elbert, Donald L; Patterson, Bruce W; Bateman, Randall J

    2015-03-01

    Amyloid beta (Aβ) peptides, and in particular Aβ42, are found in senile plaques associated with Alzheimer's disease. A compartmental model of Aβ production, exchange and irreversible loss was recently developed to explain the kinetics of isotope-labeling of Aβ peptides collected in cerebrospinal fluid (CSF) following infusion of stable isotope-labeled leucine in humans. The compartmental model allowed calculation of the rates of production, irreversible loss (or turnover) and short-term exchange of Aβ peptides. Exchange of Aβ42 was particularly pronounced in amyloid plaque-bearing participants. In the current work, we describe in much greater detail the characteristics of the compartmental model to two distinct audiences: physician-scientists and biokineticists. For physician-scientists, we describe through examples the types of questions the model can and cannot answer, as well as correct some misunderstandings of previous kinetic analyses applied to this type of isotope labeling data. For biokineticists, we perform a system identifiability analysis and a sensitivity analysis of the kinetic model to explore the global and local properties of the model. Combined, these analyses motivate simplifications from a more comprehensive physiological model to the final model that was previously presented. The analyses clearly demonstrate that the current dataset and compartmental model allow determination with confidence a single 'turnover' parameter, a single 'exchange' parameter and a single 'delay' parameter. When combined with CSF concentration data for the Aβ peptides, production rates may also be obtained.

  2. Comprehensive Genetic Analysis of Japanese Autosomal Dominant Sensorineural Hearing Loss Patients

    PubMed Central

    Iwasa, Yoh-ichiro; Nishio, Shin-ya; Usami, Shin-ichi

    2016-01-01

    Background In general, autosomal dominant inherited hearing loss does not have a founder mutation, with the causative mutation different in each family. For this reason, there has been a strong need for efficient diagnosis methods for autosomal dominant sensorineural hearing loss (ADSNHL) patients. This study sought to verify the effectiveness of our analysis algorithm for the screening of ADSNHL patients as well as the usefulness of the massively parallel DNA sequencing (MPS). Subjects and Methods Seventy-five Japanese ADSNHL patients from 53 ENT departments nationwide participated in this study. We conducted genetic analysis of 75 ADSNHL patients using the Invader assay, TaqMan genotyping assay and MPS-based genetic screening. Results A total of 46 (61.3%) ADSNHL patients were found to have at least one candidate gene variant. Conclusion We were able to achieve a high mutation detection rate through the combination of the Invader assay, TaqMan genotyping assay and MPS. MPS could be used to successfully identify mutations in rare deafness genes. PMID:27911912

  3. Carboxylic acid functional group analysis using constant neutral loss scanning-mass spectrometry.

    PubMed

    Dron, Julien; Eyglunent, Gregory; Temime-Roussel, Brice; Marchand, Nicolas; Wortham, Henri

    2007-12-12

    The present study describes the development of a new analytical technique for the functional group determination of the carboxylic moiety using atmospheric pressure chemical ionization-mass spectrometry (APCI-MS/MS) operated in the constant neutral loss scanning (CNLS) mode. Carboxylic groups were first derivatized into their corresponding methyl esters by reacting with BF3/methanol mix and the reaction mixture was then directly injected into the APCI chamber. The loss of methanol (m/z = 32 amu) resulting from the fragmentation of the protonated methyl esters was then monitored. Applying this method together with a statistical approach to reference mixtures containing 31 different carboxylic acids at randomly calculated concentrations demonstrated its suitability for quantitative functional group measurements with relative standard deviations below 15% and a detection limit of 0.005 mmol L(-1). Its applicability to environmental matrices was also shown through the determination of carboxylic acid concentrations inside atmospheric aerosol samples. To the best of our knowledge, it is the first time that the tandem mass spectrometry was successfully applied to functional group analysis, offering great perspectives in the characterization of complex mixtures which are prevailing in the field of environmental analysis as well as in the understanding of the chemical processes occurring in these matrices.

  4. Socioeconomic status as a factor in Indigenous and non-Indigenous children with hearing loss: analysis of national survey data.

    PubMed

    Simpson, Andrea; Enticott, Joanne C; Douglas, Jacinta

    2016-09-23

    In this paper, the association between socioeconomic status and speech, language and communication outcomes for primary-school-going children with hearing loss using population survey data was analysed. The dataset used for analysis consisted of 289973 children in total, of which 3174 children had hearing loss. For all children, higher socioeconomic status was positively correlated with better speech, language and communication outcomes. A hearing loss was indicated for 1% of non-Indigenous children and 4.3% of Indigenous children. Non-Indigenous children with hearing loss were found to be fairly evenly distributed by socioeconomic status, whereas Indigenous children with hearing loss were found to be statistically significantly more likely to be living in the most disadvantaged socioeconomic areas. Socioeconomic status was found to affect developmental outcomes for all children, regardless of Indigenous and hearing loss status.

  5. Speed of disentanglement in multiqubit systems under a depolarizing channel

    SciTech Connect

    Zhang, Fu-Lin Jiang, Yue; Liang, Mai-Lin

    2013-06-15

    We investigate the speed of disentanglement in the multiqubit systems under the local depolarizing channel, in which each qubit is independently coupled to the environment. We focus on the bipartition entanglement between one qubit and the remaining qubits constituting the system, which is measured by the negativity. For the two-qubit system, the speed for the pure state completely depends on its entanglement. The upper and lower bounds of the speed for arbitrary two-qubit states, and the necessary conditions for a state achieving them, are obtained. For the three-qubit system, we study the speed for pure states, whose entanglement properties can be completely described by five local-unitary-transformation invariants. An analytical expression of the relation between the speed and the invariants is derived. The speed is enhanced by the three-tangle which is the entanglement among the three qubits, but reduced by the two-qubit correlations outside the concurrence. The decay of the negativity can be restrained by the other two negativity with the coequal sense. The unbalance between two qubits can reduce the speed of disentanglement of the remaining qubit in the system, and even can retrieve the entanglement partially. For the k-qubit systems in an arbitrary superposition of Greenberger–Horne–Zeilinger state and W state, the speed depends almost entirely on the amount of the negativity when k increases to five or six. An alternative quantitative definition for the robustness of entanglement is presented based on the speed of disentanglement, with comparison to the widely studied robustness measured by the critical amount of noise parameter where the entanglement vanishes. In the limit of large number of particles, the alternative robustness of the Greenberger–Horne–Zeilinger-type states is inversely proportional to k, and the one of the W states approaches 1/√(k)

  6. Speed of disentanglement in multiqubit systems under a depolarizing channel

    NASA Astrophysics Data System (ADS)

    Zhang, Fu-Lin; Jiang, Yue; Liang, Mai-Lin

    2013-06-01

    We investigate the speed of disentanglement in the multiqubit systems under the local depolarizing channel, in which each qubit is independently coupled to the environment. We focus on the bipartition entanglement between one qubit and the remaining qubits constituting the system, which is measured by the negativity. For the two-qubit system, the speed for the pure state completely depends on its entanglement. The upper and lower bounds of the speed for arbitrary two-qubit states, and the necessary conditions for a state achieving them, are obtained. For the three-qubit system, we study the speed for pure states, whose entanglement properties can be completely described by five local-unitary-transformation invariants. An analytical expression of the relation between the speed and the invariants is derived. The speed is enhanced by the three-tangle which is the entanglement among the three qubits, but reduced by the two-qubit correlations outside the concurrence. The decay of the negativity can be restrained by the other two negativity with the coequal sense. The unbalance between two qubits can reduce the speed of disentanglement of the remaining qubit in the system, and even can retrieve the entanglement partially. For the k-qubit systems in an arbitrary superposition of Greenberger-Horne-Zeilinger state and W state, the speed depends almost entirely on the amount of the negativity when k increases to five or six. An alternative quantitative definition for the robustness of entanglement is presented based on the speed of disentanglement, with comparison to the widely studied robustness measured by the critical amount of noise parameter where the entanglement vanishes. In the limit of large number of particles, the alternative robustness of the Greenberger-Horne-Zeilinger-type states is inversely proportional to k, and the one of the W states approaches 1/√{k}.

  7. Study Case of Air-Mass Modification over Poland and Romania Observed by the Means of Multiwavelength Raman Depolarization Lidars

    NASA Astrophysics Data System (ADS)

    Costa-Surós, Montserrat; Janicka, Lucja; Stachlewska, Iwona S.; Nemuc, Anca; Talianu, Camelia; Heese, Birgit; Engelmann, Ronny

    2016-06-01

    An air-mass modification, on its way from Poland to Romania, observed between 19-21 July 2014 is discussed. The air-mass was investigated using data of two multi-wavelength lidars capable of performing regular elastic, depolarization and Raman measurements in Warsaw, Poland, and in Magurele, Romania. The analysis was focused on evaluating optical properties of aerosol in order to search for similarities and differences in the vertical profiles describing the atmospheric layers above the two stations within given period.

  8. Intratumoral heterogeneity analysis reveals hidden associations between protein expression losses and patient survival in clear cell renal cell carcinoma

    PubMed Central

    Devarajan, Karthik; Parsons, Theodore; Wang, Qiong; O'Neill, Raymond; Solomides, Charalambos; Peiper, Stephen C.; Testa, Joseph R.; Uzzo, Robert; Yang, Haifeng

    2017-01-01

    Intratumoral heterogeneity (ITH) is a prominent feature of kidney cancer. It is not known whether it has utility in finding associations between protein expression and clinical parameters. We used ITH that is detected by immunohistochemistry (IHC) to aid the association analysis between the loss of SWI/SNF components and clinical parameters.160 ccRCC tumors (40 per tumor stage) were used to generate tissue microarray (TMA). Four foci from different regions of each tumor were selected. IHC was performed against PBRM1, ARID1A, SETD2, SMARCA4, and SMARCA2. Statistical analyses were performed to correlate biomarker losses with patho-clinical parameters. Categorical variables were compared between groups using Fisher's exact tests. Univariate and multivariable analyses were used to correlate biomarker changes and patient survivals. Multivariable analyses were performed by constructing decision trees using the classification and regression trees (CART) methodology. IHC detected widespread ITH in ccRCC tumors. The statistical analysis of the “Truncal loss” (root loss) found additional correlations between biomarker losses and tumor stages than the traditional “Loss in tumor (total)”. Losses of SMARCA4 or SMARCA2 significantly improved prognosis for overall survival (OS). Losses of PBRM1, ARID1A or SETD2 had the opposite effect. Thus “Truncal Loss” analysis revealed hidden links between protein losses and patient survival in ccRCC. PMID:28445125

  9. Quantitative Analysis of Land Loss in Coastal Louisiana Using Remote Sensing

    NASA Astrophysics Data System (ADS)

    Wales, P. M.; Kuszmaul, J.; Roberts, C.

    2005-12-01

    For the past thirty-five years the land loss along the Louisiana Coast has been recognized as a growing problem. One of the clearest indicators of this land loss is that in 2000 smooth cord grass (spartina alterniflora) was turning brown well before its normal hibernation period. Over 100,000 acres of marsh were affected by the 2000 browning. In 2001 data were collected using low altitude helicopter based transects of the coast, with 7,400 data points being collected by researchers at the USGS, National Wetlands Research Center, and Louisiana Department of Natural Resources. The surveys contained data describing the characteristics of the marsh, including latitude, longitude, marsh condition, marsh color, percent vegetated, and marsh die-back. Creating a model that combines remote sensing images, field data, and statistical analysis to develop a methodology for estimating the margin of error in measurements of coastal land loss (erosion) is the ultimate goal of the study. A model was successfully created using a series of band combinations (used as predictive variables). The most successful band combinations or predictive variables were the braud value [(Sum Visible TM Bands - Sum Infrared TM Bands)/(Sum Visible TM Bands + Sum Infrared TM Bands)], TM band 7/ TM band 2, brightness, NDVI, wetness, vegetation index, and a 7x7 autocovariate nearest neighbor floating window. The model values were used to generate the logistic regression model. A new image was created based on the logistic regression probability equation where each pixel represents the probability of finding water or non-water at that location in each image. Pixels within each image that have a high probability of representing water have a value close to 1 and pixels with a low probability of representing water have a value close to 0. A logistic regression model is proposed that uses seven independent variables. This model yields an accurate classification in 86.5% of the locations considered in the

  10. Extraterrestrial material analysis: loss of amino acids during liquid-phase acid hydrolysis

    NASA Astrophysics Data System (ADS)

    Buch, Arnaud; Brault, Amaury; Szopa, Cyril; Freissinet, Caroline

    2015-04-01

    Searching for building blocks of life in extraterrestrial material is a way to learn more about how life could have appeared on Earth. With this aim, liquid-phase acid hydrolysis has been used, since at least 1970 , in order to extract amino acids and other organic molecules from extraterrestrial materials (e.g. meteorites, lunar fines) or Earth analogues (e.g. Atacama desert soil). This procedure involves drastic conditions such as heating samples in 6N HCl for 24 h, either under inert atmosphere/vacuum, or air. Analysis of the hydrolyzed part of the sample should give its total (free plus bound) amino acid content. The present work deals with the influence of the 6N HCl hydrolysis on amino acid degradation. Our experiments have been performed on a standard solution of 17 amino acids. After liquid-phase acid hydrolysis (6N HCl) under argon atmosphere (24 h at 100°C), the liquid phase was evaporated and the dry residue was derivatized with N-Methyl-N-(t-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and dimethylformamide (DMF), followed by gas chromatography-mass spectrometry analysis. After comparison with derivatized amino acids from the standard solution, a significant reduction of the chromatographic peak areas was observed for most of the amino acids after liquid-phase acid hydrolysis. Furthermore, the same loss pattern was observed when the amino acids were exposed to cold 6N HCl for a short amount of time. The least affected amino acid, i.e. glycine, was found to be 73,93% percent less abundant compared to the non-hydrolyzed standard, while the most affected, i.e. histidine, was not found in the chromatograms after hydrolysis. Our experiments thereby indicate that liquid-phase acid hydrolysis, even under inert atmosphere, leads to a partial or total loss of all of the 17 amino acids present in the standard solution, and that a quick cold contact with 6N HCl is sufficient to lead to a loss of amino acids. Therefore, in the literature, the reported increase

  11. Does Diet-Induced Weight Loss Lead to Bone Loss in Overweight or Obese Adults? A Systematic Review and Meta-Analysis of Clinical Trials.

    PubMed

    Zibellini, Jessica; Seimon, Radhika V; Lee, Crystal M Y; Gibson, Alice A; Hsu, Michelle S H; Shapses, Sue A; Nguyen, Tuan V; Sainsbury, Amanda

    2015-12-01

    Diet-induced weight loss has been suggested to be harmful to bone health. We conducted a systematic review and meta-analysis (using a random-effects model) to quantify the effect of diet-induced weight loss on bone. We included 41 publications involving overweight or obese but otherwise healthy adults who followed a dietary weight-loss intervention. The primary outcomes examined were changes from baseline in total hip, lumbar spine, and total body bone mineral density (BMD), as assessed by dual-energy X-ray absorptiometry (DXA). Secondary outcomes were markers of bone turnover. Diet-induced weight loss was associated with significant decreases of 0.010 to 0.015 g/cm(2) in total hip BMD for interventions of 6, 12, or 24 (but not 3) months' duration (95% confidence intervals [CIs], -0.014 to -0.005, -0.021 to -0.008, and -0.024 to -0.000 g/cm(2), at 6, 12, and 24 months, respectively). There was, however, no statistically significant effect of diet-induced weight loss on lumbar spine or whole-body BMD for interventions of 3 to 24 months' duration, except for a significant decrease in total body BMD (-0.011 g/cm(2); 95% CI, -0.018 to -0.003 g/cm(2)) after 6 months. Although no statistically significant changes occurred in serum concentrations of N-terminal propeptide of type I procollagen (P1NP), interventions of 2 or 3 months in duration (but not of 6, 12, or 24 months' duration) induced significant increases in serum concentrations of osteocalcin (0.26 nmol/L; 95% CI, 0.13 to 0.39 nmol/L), C-terminal telopeptide of type I collagen (CTX) (4.72 nmol/L; 95% CI, 2.12 to 7.30 nmol/L) or N-terminal telopeptide of type I collagen (NTX) (3.70 nmol/L; 95% CI, 0.90 to 6.50 nmol/L bone collagen equivalents [BCEs]), indicating an early effect of diet-induced weight loss to promote bone breakdown. These data show that in overweight and obese individuals, a single diet-induced weight-loss intervention induces a small decrease in total hip BMD, but not lumbar spine

  12. Vitamin D status and weight loss: a systematic review and meta-analysis of randomized and nonrandomized controlled weight-loss trials.

    PubMed

    Mallard, Simonette R; Howe, Anna S; Houghton, Lisa A

    2016-10-01

    Obesity is associated with lower concentrations of serum 25-hydroxyvitamin D; however, uncertainty exists as to the direction of causation. To date, meta-analyses of randomized controlled vitamin D-supplementation trials have shown no effect of raising circulating vitamin D on body weight, although several weight-loss-intervention trials have reported an increase in circulating vitamin D after weight reduction. We undertook a systematic review and meta-analysis of randomized and nonrandomized controlled trials to determine whether weight loss compared with weight maintenance leads to an increase in serum 25-hydroxyvitamin D. A systematic search for controlled weight-loss-intervention studies published up to 31 March 2016 was performed. Studies that included participants of any age with changes in adiposity and serum 25-hydroxyvitamin D as primary or secondary outcomes were considered eligible. We identified 4 randomized controlled trials (n = 2554) and 11 nonrandomized controlled trials (n = 917) for inclusion in the meta-analysis. Random assignment to weight loss compared with weight maintenance resulted in a greater increase in serum 25-hydroxyvitamin D with a mean difference of 3.11 nmol/L (95% CI: 1.38, 4.84 nmol/L) between groups, whereas a mean difference of 4.85 nmol/L (95% CI: 2.59, 7.12 nmol/L) was observed in nonrandomized trials. No evidence for a dose-response effect of weight loss on the change in serum 25-hydroxyvitamin D was shown overall. Our results indicate that vitamin D status may be marginally improved with weight loss in comparison with weight maintenance under similar conditions of supplemental vitamin D intake. Although additional studies in unsupplemented individuals are needed to confirm these findings, our results support the view that the association between obesity and lower serum 25-hydroxyvitamin D may be due to reversed causation with increased adiposity leading to suboptimal concentrations of circulating vitamin D. This trial was

  13. Probiotics for weight loss: a systematic review and meta-analysis.

    PubMed

    Park, Sunmin; Bae, Ji-Hyun

    2015-07-01

    The intestinal microbiota has been reported to be one of the potential determinants of obesity in recent human and animal studies. Probiotics may affect the gut microbiota to modulate obesity. This systematic review aims to summarize and critically evaluate the evidence from clinical trials that have tested the effectiveness of probiotics or foods containing probiotics as a treatment for weight loss. Literature searches of electronic databases such as PubMed, Cochrane Library, and EMBASE were conducted. Methodological quality was assessed using body weight and body mass index (BMI). Initial searches yielded 368 articles. Of these, only 9 met the selection criteria. Because of insufficient data, only 4 of the studies were randomized controlled trials (RCTs) that compared the therapeutic efficacy of probiotics with placebo. The meta-analysis of these data showed no significant effect of probiotics on body weight and BMI (body weight, n = 196; mean difference, -1.77; 95% confidence interval, -4.84 to 1.29; P = .26; BMI, n = 154; mean difference, 0.77; 95% confidence interval, -0.24 to 1.78; P = .14). However, the total number of RCTs included in the analysis, the total sample size, and the methodological quality of the primary studies were too low to draw definitive conclusions. Thus, more rigorously designed RCTs are necessary to examine the effect of probiotics on body weight in greater detail. Collectively, the RCTs examined in this meta-analysis indicated that probiotics have limited efficacy in terms of decreasing body weight and BMI and were not effective for weight loss.

  14. De-polarization of a CdZnTe radiation detector by pulsed infrared light

    SciTech Connect

    Dědič, V. Franc, J.; Rejhon, M.; Grill, R.; Zázvorka, J.; Sellin, P. J.

    2015-07-20

    This work is focused on a detailed study of pulsed mode infrared light induced depolarization of CdZnTe detectors operating at high photon fluxes. This depolarizing effect is a result of the decrease of positive space charge that is caused by the trapping of photogenerated holes at a deep level. The reduction in positive space charge is due to the optical transition of electrons from a valence band to the deep level due to additional infrared illumination. In this paper, we present the results of pulse mode infrared depolarization, by which it is possible to keep the detector in the depolarized state during its operation. The demonstrated mechanism represents a promising way to increase the charge collection efficiency of CdZnTe X-ray detectors operating at high photon fluxes.

  15. A depolarization and attenuation experiment using the CTS satellite. [meteorological radar

    NASA Technical Reports Server (NTRS)

    Bostian, C. W.; Holt, S. B., Jr.; Kauffman, S. R.; Manus, E. A.; Marshall, R. E.; Stutzman, W. L.; Wiley, P. H.

    1977-01-01

    Rain attenuation and depolarization data collected on the communications technology satellite 11.7 GHz downlink, and changes made in equipment following rain leak damage to the parametric amplifier are discussed. A 15 GHz radar system is described.

  16. Depolarized light scattering studies of the collision induced polarizability anisotropy of atoms and spherical top molecules

    NASA Astrophysics Data System (ADS)

    Dunmur, D. A.; Manterfield, M. R.; Robinson, D. J.

    New measurements are reported of the density dependent depolarization ratio for argon, krypton, xenon, methane and sulphur hexafluoride, and the results are analysed to provide values for the second and third depolarization virial coefficients. The relationships between the second depolarization virial coefficient, the zeroth moment of the two-body Rayleigh spectrum and the second Kerr virial coefficient are considered, and it is shown that they now provide consistent results for the collision-induced pair polarizability anisotropy. Former inconsistencies are attributed to insufficient allowance for the effects of three-body interactions. Calculations of the second and third depolarization virial coefficients based on the DID model and using the Maitland-Smith potential are in excellent agreement with the experimental results for argon, krypton and xenon.

  17. Aerosol Properties over Southeastern China from Multi-Wavelength Raman and Depolarization Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Heese, Birgit; Althausen, Dietrich; Baars, Holger; Bohlmann, Stephanie; Deng, Ruru

    2016-06-01

    A dataset of particle optical properties of highly polluted urban aerosol over the Pearl River Delta, Guangzhou, China is presented. The data were derived from multi-wavelengths Raman and depolarization lidar PollyXT and AERONET sun photometer measurements. The measurement campaign was conducted from Nov 2011 to June 2012. High aerosol optical depth was observed in the polluted atmosphere over this megacity, with a mean value of 0.54 ± 0.33 and a peak value of even 1.9. For the particle characterization the lidar ratio and the linear particle depolarization ratio, both at 532 nm, were used. The mean values of these properties are 48.0 sr ± 10.7 sr for the lidar ratio and 4%+-4% for the particle depolarization ratio, which means most depolarization measurements stayed below 10%. So far, most of these results indicate urban pollution particles mixed with particles arisen from biomass and industrial burning.

  18. Depolarization in the diffraction of polarized neutrons by a tungsten-186 single crystal

    SciTech Connect

    Aleksandrov, Y.A.; Vavra, J.; Vrana, M.; Goralik, L.; Kulda, I.; Lukash, P.; Mikula, P.; Chalupa, B.

    1985-09-10

    An observation of a depolarization of neutrons upon diffraction confirms that the paramagnetic phase of tungsten containing a microscopic cobalt impurity has regions in which the magnetic moments are ordered (magnetic clusters).

  19. Early depolarizing GABA controls critical period plasticity in the rat visual cortex

    PubMed Central

    Deidda, Gabriele; Allegra, Manuela; Cerri, Chiara; Naskar, Shovan; Bony, Guillaume; Zunino, Giulia; Bozzi, Yuri; Caleo, Matteo; Cancedda, Laura

    2014-01-01

    SUMMARY Hyperpolarizing and inhibitory GABA regulates “critical periods” for plasticity in sensory cortices. Here, we examine the role of early, depolarizing GABA in controlling plasticity mechanisms. We report that brief interference with depolarizing GABA during early development prolonged critical period plasticity in visual cortical circuits, without affecting overall development of the visual system. The effects on plasticity were accompanied by dampened inhibitory neurotransmission, down-regulation of BDNF expression, and reduced density of extracellular matrix-perineuronal nets. Early interference with depolarizing GABA decreased perinatal BDNF signaling, and pharmacological increase of BDNF signaling during GABA interference rescued the effects on plasticity and its regulators later in life. We conclude that depolarizing GABA exerts a long-lasting, selective modulation of plasticity of cortical circuits by a strong crosstalk with BDNF. PMID:25485756

  20. Development of multiple scattering polarization lidar to observe depolarization ratio of optically thick low level clouds

    NASA Astrophysics Data System (ADS)

    Okamoto, Hajime; Sato, Kaori; Nishizawa, Tomoaki; Sugimoto, Nobuo; Jin, Yoshitaka

    2017-02-01

    We have examined the characteristic of backscattering coefficient and depolarization ratio that are affected by multiple scattering in optically thick water clouds. We used observations obtained by the Multiple Field of view Multiple Scattering Polarization Lidar (MFMSPL) system. The MFMSPL was the first ground-based lidar that can detect depolarization ratio of optically thick clouds and it has 8 channels, i.e., 4 for parallel channels and another 4 for perpendicular ones and achieved total FOV of 70mrad. The MFMSPL offers a unique opportunity to simulate and study space-borne lidar signals including depolarization ratio such as from Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) lidar. It was shown that the attenuated backscattering coefficient and depolarization ratio constructed by using 8 channel observations by MFMSPL were comparable to the values obtained by CALIPSO lidar.

  1. Acetylcholine Facilitates a Depolarization-Induced Enhancement of Inhibition in Rat CA1 Pyramidal Neurons.

    PubMed

    Domínguez, Soledad; Fernández de Sevilla, David; Buño, Washington

    2017-01-01

    Cholinergic mechanisms in the hippocampus regulate forms of synaptic plasticity linked with cognition and spatial navigation, but the underlying mechanisms remain largely unknown. Here, in rat hippocampal CA1 pyramidal cells under blockade of ionotropic glutamate receptors, we report that a single acetylcholine pulse and repeated depolarization activated a robust and enduring postsynaptic depolarization-induced enhancement of inhibition (DEI) that masked a presynaptic depolarization-induced suppression of inhibition (DSI). Increased cytosolic Ca2+ and M1-muscarinic receptor activation caused the rise in voltage-sensitive α5βγ2-containing γ-aminobutyric acid type-A receptors that generated DEI. In summary, this muscarinic-mediated activity-dependent plasticity rapidly transfers depolarization effects on inhibition from presynaptic suppression or DSI to postsynaptic enhancement or DEI, a change potentially relevant in behavior.

  2. Methods and apparatus for using gas and liquid phase cathodic depolarizers

    NASA Technical Reports Server (NTRS)

    Murphy, Oliver J. (Inventor); Hitchens, G. Duncan (Inventor)

    1998-01-01

    The invention provides methods for using gas and liquid phase cathodic depolarizers in an electrochemical cell having a cation exchange membrane in intimate contact with the anode and cathode. The electrochemical conversion of cathodic depolarizers at the cathode lowers the cell potential necessary to achieve a desired electrochemical conversion, such as ozone evolution, at the anode. When gaseous cathodic depolarizers, such as oxygen, are used, a gas diffusion cathode having the cation exchange membrane bonded thereto is preferred. When liquid phase cathodic depolarizers are used, the cathode may be a flow-by electrode, flow-through electrode, packed-bed electrode or a fluidized-bed electrode in intimate contact with the cation exchange membrane.

  3. Identification and analysis of unitary pseudogenes: historic and contemporary gene losses in humans and other primates

    PubMed Central

    2010-01-01

    Background Unitary pseudogenes are a class of unprocessed pseudogenes without functioning counterparts in the genome. They constitute only a small fraction of annotated pseudogenes in the human genome. However, as they represent distinct functional losses over time, they shed light on the unique features of humans in primate evolution. Results We have developed a pipeline to detect human unitary pseudogenes through analyzing the global inventory of orthologs between the human genome and its mammalian relatives. We focus on gene losses along the human lineage after the divergence from rodents about 75 million years ago. In total, we identify 76 unitary pseudogenes, including previously annotated ones, and many novel ones. By comparing each of these to its functioning ortholog in other mammals, we can approximately date the creation of each unitary pseudogene (that is, the gene 'death date') and show that for our group of 76, the functional genes appear to be disabled at a fairly uniform rate throughout primate evolution - not all at once, correlated, for instance, with the 'Alu burst'. Furthermore, we identify 11 unitary pseudogenes that are polymorphic - that is, they have both nonfunctional and functional alleles currently segregating in the human population. Comparing them with their orthologs in other primates, we find that two of them are in fact pseudogenes in non-human primates, suggesting that they represent cases of a gene being resurrected in the human lineage. Conclusions This analysis of unitary pseudogenes provides insights into the evolutionary constraints faced by different organisms and the timescales of functional gene loss in humans. PMID:20210993

  4. [Multiple time scales analysis of spatial differentiation characteristics of non-point source nitrogen loss within watershed].

    PubMed

    Liu, Mei-bing; Chen, Xing-wei; Chen, Ying

    2015-07-01

    Identification of the critical source areas of non-point source pollution is an important means to control the non-point source pollution within the watershed. In order to further reveal the impact of multiple time scales on the spatial differentiation characteristics of non-point source nitrogen loss, a SWAT model of Shanmei Reservoir watershed was developed. Based on the simulation of total nitrogen (TN) loss intensity of all 38 subbasins, spatial distribution characteristics of nitrogen loss and critical source areas were analyzed at three time scales of yearly average, monthly average and rainstorms flood process, respectively. Furthermore, multiple linear correlation analysis was conducted to analyze the contribution of natural environment and anthropogenic disturbance on nitrogen loss. The results showed that there were significant spatial differences of TN loss in Shanmei Reservoir watershed at different time scales, and the spatial differentiation degree of nitrogen loss was in the order of monthly average > yearly average > rainstorms flood process. TN loss load mainly came from upland Taoxi subbasin, which was identified as the critical source area. At different time scales, land use types (such as farmland and forest) were always the dominant factor affecting the spatial distribution of nitrogen loss, while the effect of precipitation and runoff on the nitrogen loss was only taken in no fertilization month and several processes of storm flood at no fertilization date. This was mainly due to the significant spatial variation of land use and fertilization, as well as the low spatial variability of precipitation and runoff.

  5. Three-Signal Method for Accurate Measurements of Depolarization Ratio with Lidar

    NASA Technical Reports Server (NTRS)

    Reichardt, Jens; Baumgart, Rudolf; McGee, Thomsa J.

    2003-01-01

    A method is presented that permits the determination of atmospheric depolarization-ratio profiles from three elastic-backscatter lidar signals with different sensitivity to the state of polarization of the backscattered light. The three-signal method is insensitive to experimental errors and does not require calibration of the measurement, which could cause large systematic uncertainties of the results, as is the case in the lidar technique conventionally used for the observation of depolarization ratios.

  6. A review of depolarization modeling for earth-space radio paths at frequencies above 10 GHz

    NASA Technical Reports Server (NTRS)

    Bostian, C. W.; Stutzman, W. L.; Gaines, J. M.

    1982-01-01

    A review is presented of models for the depolarization, caused by scattering from raindrops and ice crystals, that limits the performance of dual-polarized satellite communication systems at frequencies above 10 GHz. The physical mechanisms of depolarization as well as theoretical formulations and empirical data are examined. Three theoretical models, the transmission, attenuation-derived, and scaling models, are described and their relative merits are considered.

  7. On the Use of Radar Depolarization Ratios for Estimating Shapes of Ice Hydrometeors in Winter Clouds.

    NASA Astrophysics Data System (ADS)

    Matrosov, Sergey Y.; Reinking, Roger F.; Kropfli, Robert A.; Martner, Brooks E.; Bartram, B. W.

    2001-03-01

    An approach is suggested to relate measurements of radar depolarization ratios and aspect ratios of predominant hydrometeors in nonprecipitating and weakly precipitating layers of winter clouds. The trends of elevation angle dependencies of depolarization ratios are first used to distinguish between columnar-type and plate-type particles. For the established particle type, values of depolarization ratios observed at certain elevation angles, for which the influence of particle orientation is minimal, are then used to estimate aspect ratios when information on particle effective bulk density is assumed or inferred from other measurements. The use of different polarizations, including circular, slant-45° linear, and two elliptical polarizations, is discussed. These two elliptical polarizations are quasi-circular and quasi-linear slant-45° linear, and both are currently achievable with the National Oceanic and Atmospheric Administration Environmental Technology Laboratory's Ka-band radar. In comparison with the true circular and slant-45° linear polarizations, the discussed elliptical polarizations provide a stronger signal in the `weak' radar receiver channel; however, it is at the expense of diminished dynamic range of depolarization ratio variations. For depolarization measurements at the radar elevation angles that do not show much sensitivity to particle orientations, the available quasi-circular polarization provides a better depolarization contrast between nonspherical and spherical particles than does the available quasi-linear slant-45°polarization. The use of the proposed approach is illustrated with the experimental data collected during a recent field experiment. It is shown that it allows successful differentiation among pristine planar crystals, rimed planar crystals, long columns, blocky columns, and graupel. When a reasonable assumption about particle bulk density is made, quantitative estimates of particle aspect ratios from radar depolarization

  8. Muscle cell depolarization induces a gain in surface GLUT4 via reduced endocytosis independently of AMPK.

    PubMed

    Wijesekara, Nadeeja; Tung, Amanda; Thong, Farah; Klip, Amira

    2006-06-01

    Contracting skeletal muscle increases glucose uptake to sustain energy demand. This is achieved through a gain in GLUT4 at the membrane, but the traffic mechanisms and regulatory signals involved are unknown. Muscle contraction is elicited by membrane depolarization followed by a rise in cytosolic Ca2+ and actomyosin activation, drawing on ATP stores. It is unknown whether one or more of these events triggers the rise in surface GLUT4. Here, we investigate the effect of membrane depolarization on GLUT4 cycling using GLUT4myc-expressing L6 myotubes devoid of sarcomeres and thus unable to contract. K+-induced membrane depolarization elevated surface GLUT4myc, and this effect was additive to that of insulin, was not prevented by inhibiting phosphatidylinositol 3-kinase (PI3K) or actin polymerization, and did not involve Akt activation. Instead, depolarization elevated cytosolic Ca2+, and the surface GLUT4myc elevation was prevented by dantrolene (an inhibitor of Ca2+ release from sarcoplasmic reticulum) and by extracellular Ca2+ chelation. Ca2+-calmodulin-dependent protein kinase-II (CaMKII) was not phosphorylated after 10 min of K+ depolarization, and the CaMK inhibitor KN62 did not prevent the gain in surface GLUT4myc. Interestingly, although 5'-AMP-activated protein kinase (AMPK) was phosphorylated upon depolarization, lowering AMPKalpha via siRNA did not alter the surface GLUT4myc gain. Conversely, the latter response was abolished by the PKC inhibitors bisindolylmaleimide I and calphostin C. Unlike insulin, K+ depolarization caused only a small increase in GLUT4myc exocytosis and a major reduction in its endocytosis. We propose that K+ depolarization reduces GLUT4 internalization through signals and mechanisms distinct from those engaged by insulin. Such a pathway(s) is largely independent of PI3K, Akt, AMPK, and CaMKII but may involve PKC.

  9. Analysis of Loss-of-Offsite-Power Events 1998–2012

    SciTech Connect

    T. E. Wierman

    2013-10-01

    Loss of offsite power (LOOP) can have a major negative impact on a power plant’s ability to achieve and maintain safe shutdown conditions. Risk analyses performed loss of all alternating current power contributes over 70% of the overall risk at some U.S. nuclear plants. LOOP event and subsequent restoration of offsite power are important inputs to plant probabilistic risk assessments. This report presents a statistical and engineering analysis of LOOP frequencies and durations at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience from fiscal year 1998 through 2012. Frequencies and durations were determined for four event categories: plant-centered, switchyard-centered, grid-related, and weather-related. The EDG failure modes considered are failure to start, failure to load and run, and failure to run more than 1 hour. The component reliability estimates and the reliability data are trended for the most recent 10-year period while yearly estimates for reliability are provided for the entire active period. A statistically significant increase in industry performance was identified for plant-centered and switchyard-centered LOOP frequencies. There is no statistically significant trend in LOOP durations.

  10. Neutron activation analysis of aerosols in conjunction with a loss-free counter

    SciTech Connect

    Biegalski, S.R.; Heydorn, K.; Landsberger, S.

    1994-12-31

    As part of an ongoing Arctic environmental research program, aerosol samples were collected on cellulose acetate filters at Station Nord in Greenland by the National Environmental Research Institute of Denmark. These samples were then given to the Riso National Laboratory in Denmark for evaluation by neutron activation analysis (NAA). Even though loss-free counters have been available for some with good results, little information has appeared in the literature in its use for actual samples. At Riso National Laboratory the samples were irradiated in the DR3 reactor and then counted on a GAMMA-X high-purity germanium (HPGe) counter with a Nuclear Data ND 599 loss-free counting (LFC) module. The aerosol filters were quite varied in their elemental depositions, and LFC was especially utilized to accommodate for the wide range of dead times encountered with the counting of short-lived isotopes. In some cases the fast decay of isotopes over the count along with pulse pileup problems would have made the use of other dead-time correction methods unreliable.

  11. Depolarization of synchrotron radiation in a multilayer magneto-ionic medium

    NASA Astrophysics Data System (ADS)

    Shneider, C.; Haverkorn, M.; Fletcher, A.; Shukurov, A.

    2014-07-01

    Depolarization of diffuse radio synchrotron emission is classified in terms of wavelength-independent and wavelength-dependent depolarization in the context of regular magnetic fields and of both isotropic and anisotropic turbulent magnetic fields. Previous analytical formulas for depolarization due to differential Faraday rotation are extended to include internal Faraday dispersion concomitantly, for a multilayer synchrotron emitting and Faraday rotating magneto-ionic medium. In particular, depolarization equations for a two- and three-layer system (disk-halo, halo-disk-halo) are explicitly derived. To both serve as a "user's guide" to the theoretical machinery and as an approach for disentangling line-of-sight depolarization contributions in face-on galaxies, the analytical framework is applied to data from a small region in the face-on grand-design spiral galaxy M 51. The effectiveness of the multiwavelength observations in constraining the pool of physical depolarization scenarios is illustrated for a two- and three-layer model along with a Faraday screen system for an observationally motivated magnetic field configuration.

  12. Time-loss injuries versus non-time-loss injuries in the first team rugby league football: a pooled data analysis.

    PubMed

    Gissane, Conor; Hodgson, Lisa; Jennings, De

    2012-09-01

    To describe the injury rates in first team rugby league in terms of those injuries that require missed playing time and those that do not. A pooled data analysis from 2 independent databases. Rugby league match and training environment over several seasons from 1990 to 2003. Injuries were reported as rates per 1000 hours of participation and as percentages with their associated 95% confidence intervals (CIs). A total of 1707 match injuries were recorded. Of these injuries, 257 required players to miss the subsequent match. The remaining 1450 injuries did not require players to miss the next game. They represented 85% (95% CI, 83-87) of all injuries received and recorded. The ratio of non-time-loss (NTL) to time-loss (TL) injuries was 5.64 (95% CI, 4.96-6.42). There were 450 training injuries, of which 81 were TL injuries and 369 NTL injuries. The NTL training injury rate was 4.56 (95% CI, 3.58-5.79) times higher than TL injury rate. Non-time-loss injuries represent the largest proportion of injuries in rugby league. If NTL injuries are not recorded, the workload of practitioners is likely to be severely underestimated.

  13. Electron beam loss assumptions for ELI-NPMEGa-ray radioprotection analysis

    SciTech Connect

    Deis, G A

    2011-10-06

    normal operation, the locations of other beam losses and the estimated current and energy of the lost beam are listed in table 3. In addition to these 'normal' beam losses, it is assumed that the beam may be accidentally mis-steered by up to 1 degree at every steering magnet, so that it hits the surrounding beam tube and other structures. This loss can be modeled as occurring at the locations listed in table 2, numbers 1-7 and 16-21. Similarly, it is assumed that any of the dipole magnets, in chicanes or at the beam dump, may fail, resulting in total beam loss straight ahead. These locations can be assumed to be the same as listed in table 2, numbers 8-10, 12-14, 22-24, 26, and 27. The data provided above are estimates of the beam loss, for the purpose of calculating radiation source terms. Dark current estimates are conservative, until we acquire actual operational data. Neither the estimated currents nor the estimated energies listed above contain any intentional margin. when they have performed similar calculations for their own purposes, they have typitally added approximately 10% to the beam energy to provide some overall margin in the analysis.

  14. Associating ecosystem service losses with indicators of toxicity in habitat equivalency analysis.

    PubMed

    Cacela, Dave; Lipton, Joshua; Beltman, Douglas; Hansen, James; Wolotira, Robert

    2005-03-01

    Habitat equivalency analysis (HEA) was developed as a tool to scale mitigation or restoration when habitat is contaminated by hazardous substances or has been otherwise harmed by anthropogenic activities. Applying HEA involves balancing reductions in habitat quality against gains from restoration actions, and quantifying changes in habitat quality in terms of ecological services. We propose a framework for developing ecological service definitions and measures that incorporate knowledge about the impacts of chemical contaminants on biota. We describe a general model for integrating multiple lines of evidence about the toxicity of hazardous substances to allow mapping of toxicological inputs to ecological service losses. We provide an example of how this framework might be used in a HEA that quantifies ecological services provided by estuarine sediments contaminated with polycyclic aromatic hydrocarbons.

  15. A simplified analysis of propulsion installation losses for computerized aircraft design

    NASA Technical Reports Server (NTRS)

    Morris, S. J., Jr.; Nelms, W. P., Jr.; Bailey, R. O.

    1976-01-01

    A simplified method is presented for computing the installation losses of aircraft gas turbine propulsion systems. The method has been programmed for use in computer aided conceptual aircraft design studies that cover a broad range of Mach numbers and altitudes. The items computed are: inlet size, pressure recovery, additive drag, subsonic spillage drag, bleed and bypass drags, auxiliary air systems drag, boundary-layer diverter drag, nozzle boattail drag, and the interference drag on the region adjacent to multiple nozzle installations. The methods for computing each of these installation effects are described and computer codes for the calculation of these effects are furnished. The results of these methods are compared with selected data for the F-5A and other aircraft. The computer program can be used with uninstalled engine performance information which is currently supplied by a cycle analysis program. The program, including comments, is about 600 FORTRAN statements long, and uses both theoretical and empirical techniques.

  16. Uncertainty Analysis for a De-pressurised Loss of Forced Cooling Event of the PBMR Reactor

    SciTech Connect

    Jansen van Rensburg, Pieter A.; Sage, Martin G.

    2006-07-01

    This paper presents an uncertainty analysis for a De-pressurised Loss of Forced Cooling (DLOFC) event that was performed with the systems CFD (Computational Fluid Dynamics) code Flownex for the PBMR reactor. An uncertainty analysis was performed to determine the variation in maximum fuel, core barrel and reactor pressure vessel (RPV) temperature due to variations in model input parameters. Some of the input parameters that were varied are: thermo-physical properties of helium and the various solid materials, decay heat, neutron and gamma heating, pebble bed pressure loss, pebble bed Nusselt number and pebble bed bypass flows. The Flownex model of the PBMR reactor is a 2-dimensional axisymmetrical model. It is simplified in terms of geometry and some other input values. However, it is believed that the model adequately indicates the effect of changes in certain input parameters on the fuel temperature and other components during a DLOFC event. Firstly, a sensitivity study was performed where input variables were varied individually according to predefined uncertainty ranges and the results were sorted according to the effect on maximum fuel temperature. In the sensitivity study, only seven variables had a significant effect on the maximum fuel temperature (greater that 5 deg. C). The most significant are power distribution profile, decay heat, reflector properties and effective pebble bed conductivity. Secondly, Monte Carlo analyses were performed in which twenty variables were varied simultaneously within predefined uncertainty ranges. For a one-tailed 95% confidence level, the conservatism that should be added to the best estimate calculation of the maximum fuel temperature for a DLOFC was determined as 53 deg. C. This value will probably increase after some model refinements in the future. Flownex was found to be a valuable tool for uncertainly analyses, facilitating both sensitivity studies and Monte Carlo analyses. (authors)

  17. Analysis of neutral active particle loss in afterglow in krypton at 2.6 mbar pressure

    SciTech Connect

    Pejovic, Momcilo M.; Karamarkovic, Jugoslav P.; Ristic, Goran S.; Pejovic, Milic M.

    2008-01-15

    This paper presents the analysis of the surface recombination and/or de-excitation of neutral active particles in two different volume krypton-filled tubes at pressure of 2.6 mbar with 1 ppm oxygen impurities. The analysis was performed on the basis of secondary electron emission from the cathode induced by positive ions and neutral active particles using the experimental data of electrical breakdown time delay mean value t{sub d} as a function of afterglow period {tau} ('memory curve'). It was shown that the main channel of neutral active particles' loss in afterglow is their recombination and/or de-excitation on the bulb walls. The loss rate increases with the increase of available wall surface per unit of gas volume. It was also shown that in early afterglow (15 ms for the tube with smaller bulb volume and 30 ms for the tube with bigger bulb volume) positive ions are formed in the mutual collisions of neutral active particles, and these ions dominantly influence the secondary electron emission from the cathode. In late afterglow (to 30 s for the tube with smaller bulb volume and to 150 s for the tube with bigger bulb volume) neutral active particles have dominant role in secondary electron emission from the cathode. The probability for this process decreases with the increase of afterglow period as a consequence of the decrease of the concentration of neutral active particles in gas, and this probability is smaller for the tube with smaller bulb volume. The influence of additional electron yield in the electrode gap caused by gamma radiation on breakdown initiation is also analyzed. It is shown that the influence of the neutral active particles in the process of secondary electron emission in the case of gamma radiation is also significant in both early and late afterglow.

  18. Dibucaine Mitigates Spreading Depolarization in Human Neocortical Slices and Prevents Acute Dendritic Injury in the Ischemic Rodent Neocortex

    PubMed Central

    Risher, W. Christopher; Lee, Mark R.; Fomitcheva, Ioulia V.; Hess, David C.; Kirov, Sergei A.

    2011-01-01

    Background Spreading depolarizations that occur in patients with malignant stroke, subarachnoid/intracranial hemorrhage, and traumatic brain injury are known to facilitate neuronal damage in metabolically compromised brain tissue. The dramatic failure of brain ion homeostasis caused by propagating spreading depolarizations results in neuronal and astroglial swelling. In essence, swelling is the initial response and a sign of the acute neuronal injury that follows if energy deprivation is maintained. Choosing spreading depolarizations as a target for therapeutic intervention, we have used human brain slices and in vivo real-time two-photon laser scanning microscopy in the mouse neocortex to study potentially useful therapeutics against spreading depolarization-induced injury. Methodology/Principal Findings We have shown that anoxic or terminal depolarization, a spreading depolarization wave ignited in the ischemic core where neurons cannot repolarize, can be evoked in human slices from pediatric brains during simulated ischemia induced by oxygen/glucose deprivation or by exposure to ouabain. Changes in light transmittance (LT) tracked terminal depolarization in time and space. Though spreading depolarizations are notoriously difficult to block, terminal depolarization onset was delayed by dibucaine, a local amide anesthetic and sodium channel blocker. Remarkably, the occurrence of ouabain-induced terminal depolarization was delayed at a concentration of 1 µM that preserves synaptic function. Moreover, in vivo two-photon imaging in the penumbra revealed that, though spreading depolarizations did still occur, spreading depolarization-induced dendritic injury was inhibited by dibucaine administered intravenously at 2.5 mg/kg in a mouse stroke model. Conclusions/Significance Dibucaine mitigated the effects of spreading depolarization at a concentration that could be well-tolerated therapeutically. Hence, dibucaine is a promising candidate to protect the brain from

  19. Loss model for off-design performance analysis of radial turbines with pivoting-vane, variable-area stators

    NASA Technical Reports Server (NTRS)

    Meitner, P. L.; Glassman, A. J.

    1980-01-01

    An off-design performance loss model for a radial turbine with pivoting, variable-area stators is developed through a combination of analytical modeling and experimental data analysis. A viscous loss model is used for the variation in stator loss with setting angle, and stator vane end-clearance leakage effects are predicted by a clearance flow model. The variation of rotor loss coefficient with stator setting angle is obtained by means of an analytical matching of experimental data for a rotor that was tested with six stators, having throat areas from 20 to 144% of the design area. An incidence loss model is selected to obtain best agreement with experimental data. The stator vane end-clearance leakage model predicts increasing mass flow and decreasing efficiency as a result of end-clearances, with changes becoming significantly larger with decreasing stator area.

  20. Numerical analysis of an engineering structure effect on a heat loss of channel-free heat pipeline

    NASA Astrophysics Data System (ADS)

    Polovnikov, V. Yu.; Glazyrin, E. S.

    2015-01-01

    The results of mathematical modeling of thermal modes of channel-free heating network laid in the areas of influence of engineering structures, as well as numerical analysis of the heat loss of the objects submitted. The regularities of heat transfer in the system and the factors that influence the intensification of heat losses are revealed. Revealed that thermal losses heating pipes laid in the channel-free zones of influence engineering structures decreases in the range from 1.53 to 10.79%, depending on the temperature inside the engineering structures and geometric characteristics of the system. It is shown that the standard method of calculation of heat loss channel-free heating pipes gives overestimated values of heat loss.

  1. Analysis of the Loss of Forced Reactor Coolant Flow Accident in SMART using RETRAN-03/INT

    SciTech Connect

    Kim, Tae-Wan; Suh, Kune-Yull; Lee, Un-Chul; Park, Goon-Cherl; Kim, Jae-Hak

    2002-07-01

    Small and medium integral type nuclear reactors are getting much attention for the peaceful use of nuclear energy in non-electric area such as district heating, seawater desalination and ship propulsion. An integral type nuclear co-generation reactor, SMART(System-integrated Modular Advanced ReacTor, 330 MWt), has been developed by KAERI (Korea Atomic Energy Research Institute) since 1996. In this study, the safety analysis for SMART using modified RETRAN-03 code whose name is RETRAN-03/INT is performed to examine the applicability of RETRAN-03/INT code. For the safety analysis of integral reactor with helical-coiled steam generators, RETRAN-03 code has been modified and verified using experimental results. New heat transfer coefficients are added for helical-coiled steam generator. And, the heat transfer model for steam generator is modified due to the different primary and secondary side heat flow from U-tube type steam generator. The loss of forced reactor coolant flow accident is selected for safety analysis in this study. Also it is considered as a single failure that one of three trains of passive residual heat removal system is failed. The results from MARS/SMR code and RETRAN-03/INT code are compared. (authors)

  2. Cochlear neuropathy in human presbycusis: Confocal analysis of hidden hearing loss in post-mortem tissue.

    PubMed

    Viana, Lucas M; O'Malley, Jennifer T; Burgess, Barbara J; Jones, Dianne D; Oliveira, Carlos A C P; Santos, Felipe; Merchant, Saumil N; Liberman, Leslie D; Liberman, M Charles

    2015-09-01

    Recent animal work has suggested that cochlear synapses are more vulnerable than hair cells in both noise-induced and age-related hearing loss. This synaptopathy is invisible in conventional histopathological analysis, because cochlear nerve cell bodies in the spiral ganglion survive for years, and synaptic analysis requires special immunostaining or serial-section electron microscopy. Here, we show that the same quadruple-immunostaining protocols that allow synaptic counts, hair cell counts, neuronal counts and differentiation of afferent and efferent fibers in mouse can be applied to human temporal bones, when harvested within 9 h post-mortem and prepared as dissected whole mounts of the sensory epithelium and osseous spiral lamina. Quantitative analysis of five "normal" ears, aged 54-89 yrs, without any history of otologic disease, suggests that cochlear synaptopathy and the degeneration of cochlear nerve peripheral axons, despite a near-normal hair cell population, may be an important component of human presbycusis. Although primary cochlear nerve degeneration is not expected to affect audiometric thresholds, it may be key to problems with hearing in noise that are characteristic of declining hearing abilities in the aging ear. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. A spatio-temporal analysis of forest loss related to cocaine trafficking in Central America

    NASA Astrophysics Data System (ADS)

    Sesnie, Steven E.; Tellman, Beth; Wrathall, David; McSweeney, Kendra; Nielsen, Erik; Benessaiah, Karina; Wang, Ophelia; Rey, Luis

    2017-05-01

    A growing body of evidence suggests that criminal activities associated with drug trafficking networks are a progressively important driver of forest loss in Central America. However, the scale at which drug trafficking represents a driver of forest loss is not presently known. We estimated the degree to which narcotics trafficking may contribute to forest loss using an unsupervised spatial clustering of 15 spatial and temporal forest loss patch metrics developed from global forest change data. We distinguished anomalous forest loss from background loss patches for each country exhibiting potential ‘narco-capitalized’ signatures which showed a statistically significant dissimilarity from other patches in terms of size, timing, and rate of forest loss. We also compared annual anomalous forest loss with the number of cocaine shipments and volume of cocaine seized, lost, or delivered at country- and department-level. For Honduras, results from linear mixed effects models showed a highly significant relationship between anomalous forest loss and the timing of increased drug trafficking (F = 9.90, p = 0.009) that also differed significantly from temporal patterns of background forest loss (t-ratio = 2.98, p = 0.004). Other locations of high forest loss in Central America showed mixed results. The timing of increased trafficking was not significantly related to anomalous forest loss in Guatemala and Nicaragua, but significantly differed in patch size compared to background losses. We estimated that cocaine trafficking could account for between 15% and 30% of annual national forest loss in these three countries over the past decade, and 30% to 60% of loss occurred within nationally and internationally designated protected areas. Cocaine trafficking is likely to have severe and lasting consequences in terms of maintaining moist tropical forest cover in Central America. Addressing forest loss in these and other tropical locations will require a stronger

  4. Design and analysis of a toroidal tester for the measurement of core losses under axial compressive stress

    NASA Astrophysics Data System (ADS)

    Alatawneh, Natheer; Rahman, Tanvir; Lowther, David A.; Chromik, Richard

    2017-06-01

    Electric machine cores are subjected to mechanical stresses due to manufacturing processes. These stresses include radial, circumferential and axial components that may have significant influences on the magnetic properties of the electrical steel and hence, on the output and efficiencies of electrical machines. Previously, most studies of iron losses due to mechanical stress have considered only radial and circumferential components. In this work, an improved toroidal tester has been designed and developed to measure the core losses and the magnetic properties of electrical steel under a compressive axial stress. The shape of the toroidal ring has been verified using 3D stress analysis. Also, 3D electromagnetic simulations show a uniform flux density distribution in the specimen with a variation of 0.03 T and a maximum average induction level of 1.5 T. The developed design has been prototyped, and measurements were carried out using a steel sample of grade 35WW300. Measurements show that applying small mechanical stresses normal to the sample thickness rises the delivered core losses, then the losses decrease continuously as the stress increases. However, the drop in core losses at high stresses does not go lower than the free-stress condition. Physical explanations for the observed trend of core losses as a function of stress are provided based on core loss separation to the hysteresis and eddy current loss components. The experimental results show that the effect of axial compressive stress on magnetic properties of electrical steel at high level of inductions becomes less pronounced.

  5. Statistical analysis of intrinsic and extrinsic coupling losses for step-index polymer optical fibers.

    PubMed

    Werzinger, Stefan; Bunge, Christian-Alexander

    2015-08-24

    The intrinsic and extrinsic coupling losses of step-index polymer optical fibers are statistically examined by Monte Carlo simulations. In contrast to most existing models that linearly scale individual losses, a comprehensive analytic coupling loss model is used that also considers the interdependencies between mismatches in numerical aperture and core diameter, as well as radial and longitudinal offsets. As a typical example, the coupling losses of A4a.2 step-index multimode fibers are analyzed for an equilibrium mode distribution. The results show considerably less conservative coupling loss estimations than with traditional models, improving link power budgeting.

  6. Analysis of jet-propulsion-engine combustion-chamber pressure losses

    NASA Technical Reports Server (NTRS)

    Pinkel, I Irving; Shames, Harold

    1947-01-01

    The development and the use of a chart for estimating the pressure losses in jet-engine combustion chambers are described. By means of the chart, the pressure losses due to fluid friction and to momentum changes in the air flow accompanying combustion can be separately evaluated. The pressure-loss chart is based on the assumption that the pressure losses in the actual combustion chamber can be matched by those of an equivalent combustion chamber of constant cross-sectional area. The concept of the equivalent combustion chamber serves as a convenient basis for comparing the pressure-loss characteristics of combustion chambers of a variety of designs. The over-all pressure losses computed from the pressure-loss chart are within 7 percent of the experimental values for the three types of combustion chambers considered herein.

  7. Analysis of Loss-of-Offsite-Power Events 1997-2015

    SciTech Connect

    Johnson, Nancy Ellen; Schroeder, John Alton

    2016-07-01

    Loss of offsite power (LOOP) can have a major negative impact on a power plant’s ability to achieve and maintain safe shutdown conditions. LOOP event frequencies and times required for subsequent restoration of offsite power are important inputs to plant probabilistic risk assessments. This report presents a statistical and engineering analysis of LOOP frequencies and durations at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience during calendar years 1997 through 2015. LOOP events during critical operation that do not result in a reactor trip, are not included. Frequencies and durations were determined for four event categories: plant-centered, switchyard-centered, grid-related, and weather-related. Emergency diesel generator reliability is also considered (failure to start, failure to load and run, and failure to run more than 1 hour). There is an adverse trend in LOOP durations. The previously reported adverse trend in LOOP frequency was not statistically significant for 2006-2015. Grid-related LOOPs happen predominantly in the summer. Switchyard-centered LOOPs happen predominantly in winter and spring. Plant-centered and weather-related LOOPs do not show statistically significant seasonality. The engineering analysis of LOOP data shows that human errors have been much less frequent since 1997 than in the 1986 -1996 time period.

  8. Prediction of hearing outcomes by multiple regression analysis in patients with idiopathic sudden sensorineural hearing loss.

    PubMed

    Suzuki, Hideaki; Tabata, Takahisa; Koizumi, Hiroki; Hohchi, Nobusuke; Takeuchi, Shoko; Kitamura, Takuro; Fujino, Yoshihisa; Ohbuchi, Toyoaki

    2014-12-01

    This study aimed to create a multiple regression model for predicting hearing outcomes of idiopathic sudden sensorineural hearing loss (ISSNHL). The participants were 205 consecutive patients (205 ears) with ISSNHL (hearing level ≥ 40 dB, interval between onset and treatment ≤ 30 days). They received systemic steroid administration combined with intratympanic steroid injection. Data were examined by simple and multiple regression analyses. Three hearing indices (percentage hearing improvement, hearing gain, and posttreatment hearing level [HLpost]) and 7 prognostic factors (age, days from onset to treatment, initial hearing level, initial hearing level at low frequencies, initial hearing level at high frequencies, presence of vertigo, and contralateral hearing level) were included in the multiple regression analysis as dependent and explanatory variables, respectively. In the simple regression analysis, the percentage hearing improvement, hearing gain, and HLpost showed significant correlation with 2, 5, and 6 of the 7 prognostic factors, respectively. The multiple correlation coefficients were 0.396, 0.503, and 0.714 for the percentage hearing improvement, hearing gain, and HLpost, respectively. Predicted values of HLpost calculated by the multiple regression equation were reliable with 70% probability with a 40-dB-width prediction interval. Prediction of HLpost by the multiple regression model may be useful to estimate the hearing prognosis of ISSNHL. © The Author(s) 2014.

  9. Purkinje cell loss in essential tremor: Random sampling quantification and nearest neighbor analysis.

    PubMed

    Choe, Matthew; Cortés, Etty; Vonsattel, Jean-Paul G; Kuo, Sheng-Han; Faust, Phyllis L; Louis, Elan D

    2016-03-01

    Purkinje cell loss has been documented in some, although not all, postmortem studies of essential tremor. Hence, there is considerable controversy concerning the presence of Purkinje cell loss in this disease. To date, few studies have been performed. Over the past 8 years, we have assembled 50 prospectively studied cases and 25 age-matched controls; none were reported in our previous large series of 33 essential tremor and 21 controls. In addition to methods used in previous studies, the current study used a random sampling approach to quantify Purkinje cells along the Purkinje cell layer with a mean of 217 sites examined in each specimen, allowing for extensive sampling of the Purkinje cell layer within the section. For the first time, we also quantified the distance between Purkinje cell bodies-a nearest neighbor analysis. In the Purkinje cell count data collected from fifteen 100 × fields, cases had lower counts than controls in all three counting criteria (cell bodies, nuclei, and nucleoli; all P < 0.001). Purkinje cell linear density was also lower in cases than controls (all P < 0.001). Purkinje cell linear density obtained by random sampling was similarly lower in cases than controls in all three counting criteria (cell bodies, nuclei, and nucleoli, all P ≤ 0.005). In agreement with the quantitative Purkinje cell counts, the mean distance from one Purkinje cell body to another Purkinje cell body along the Purkinje cell layer was greater in cases than controls (P = 0.002). These data provide support for the neurodegeneration of cerebellar Purkinje cells in essential tremor. © 2016 International Parkinson and Movement Disorder Society.

  10. Estimating Loss-of-Coolant Accident Frequencies for the Standardized Plant Analysis Risk Models

    SciTech Connect

    S. A. Eide; D. M. Rasmuson; C. L. Atwood

    2008-09-01

    The U.S. Nuclear Regulatory Commission maintains a set of risk models covering the U.S. commercial nuclear power plants. These standardized plant analysis risk (SPAR) models include several loss-of-coolant accident (LOCA) initiating events such as small (SLOCA), medium (MLOCA), and large (LLOCA). All of these events involve a loss of coolant inventory from the reactor coolant system. In order to maintain a level of consistency across these models, initiating event frequencies generally are based on plant-type average performance, where the plant types are boiling water reactors and pressurized water reactors. For certain risk analyses, these plant-type initiating event frequencies may be replaced by plant-specific estimates. Frequencies for SPAR LOCA initiating events previously were based on results presented in NUREG/CR-5750, but the newest models use results documented in NUREG/CR-6928. The estimates in NUREG/CR-6928 are based on historical data from the initiating events database for pressurized water reactor SLOCA or an interpretation of results presented in the draft version of NUREG-1829. The information in NUREG-1829 can be used several ways, resulting in different estimates for the various LOCA frequencies. Various ways NUREG-1829 information can be used to estimate LOCA frequencies were investigated and this paper presents two methods for the SPAR model standard inputs, which differ from the method used in NUREG/CR-6928. In addition, results obtained from NUREG-1829 are compared with actual operating experience as contained in the initiating events database.

  11. Purkinje Cell Loss in Essential Tremor: Random Sampling Quantification and Nearest Neighbor Analysis

    PubMed Central

    Choe, Matthew; Cortés, Etty; Vonsattel, Jean-Paul G.; Kuo, Sheng-Han; Faust, Phyllis L.; Louis, Elan D.

    2015-01-01

    Objective Purkinje cell loss has been documented in some although not all postmortem studies of essential tremor. Hence, there is considerable controversy concerning the presence of Purkinje cell loss in this disease. To date, few studies have been performed. Methods Over the past eight years, we have assembled 50 prospectively-studied cases and 25 age-matched controls; none were reported in our prior large series of 33 essential tremor and 21 controls. In addition to methods used in prior studies, the current study used a random sampling approach to quantify Purkinje cells along the Purkinje cell layer with a mean of 217 sites examined in each specimen, allowing for extensive sampling of the Purkinje cell layer within the section. For the first time, we also quantified the distance between Purkinje cell bodies - a nearest neighbor analysis. Results In the Purkinje cell count data collected from fifteen 100x-fields, cases had lower counts than controls in all three counting criteria (cell bodies, nuclei, nucleoli, all p<0.001). Purkinje cell linear density was also lower in cases than controls (all p<0.001). Purkinje cell linear density obtained by random sampling was similarly lower in cases than controls in all three counting criteria (cell bodies, nuclei, nucleoli, all p≤0.005). In agreement with the quantitative Purkinje cell counts, the mean distance from one Purkinje cell body to another Purkinje cell body along the Purkinje cell layer was greater in cases than controls (p=0.002). Conclusions These data provide support for the neurodegeneration of cerebellar Purkinje cells in essential tremor. PMID:26861543

  12. Loss of HITS (FAM107B) expression in cancers of multiple organs: tissue microarray analysis.

    PubMed

    Nakajima, Hideo; Koizumi, Keita; Tanaka, Takuji; Ishigaki, Yasuhito; Yoshitake, Yoshino; Yonekura, Hideto; Sakuma, Tsutomu; Fukushima, Toshihiro; Umehara, Hisanori; Ueno, Soichiro; Minamoto, Toshinari; Motoo, Yoshiharu

    2012-10-01

    Family with sequence similarity 107 (FAM107) proteins consist of two subtypes, FAM107A and FAM107B in mammals, possessing a conserved N-terminal domain of unknown function. Recently we found that FAM107B, an 18 kDa nuclear protein, is expressed in a broad range of tissues and is downregulated in gastrointestinal cancer. Because FAM107B expression is amplified by heat-shock stimulation, we designated it heat shock-inducible tumor small protein (HITS). Although data related to FAM107A as a candidate tumor suppressor have been accumulated, little biological information is available for HITS. In the present study, we examined HITS expression using immunohistochemistry with tissue microarrays and performed detailed statistical analyses. By screening a high-density multiple organ tumor and normal tissue microarray, HITS expression was decreased in tumor tissues of the breast, thyroid, testis and uterine cervix as well as the stomach and colon. Further analysis of tissue microarrays of individual organs showed that loss of HITS expression in cancer tissues was statistically significant and commonly observed in distinct organs in a histological type-specific manner. The HITS expression intensity was inversely correlated with the primary tumor size in breast and thyroid cancers. In addition, effects of tetracycline-inducible HITS expression on tumor growth were investigated in vivo. Forced expression of HITS inhibited tumor xenograft proliferation, compared with the mock-treated tumor xenograft model. These results show that loss of HITS expression is a common phenomenon observed in cancers of distinct organs and involved in tumor development and proliferation.

  13. Two Distinct Mechanisms Mediate Potentiating Effects of Depolarization on Synaptic Transmission

    PubMed Central

    Ludwar, Bjoern Ch.; Evans, Colin G.; Jing, Jian; Cropper, Elizabeth C.

    2009-01-01

    Two distinct mechanisms mediate potentiating effects of depolarization on synaptic transmission. Recently there has been renewed interest in a type of plasticity in which a neuron's somatic membrane potential influences synaptic transmission. We study mechanisms that mediate this type of control at a synapse between a mechanoafferent, B21, and B8, a motor neuron that receives chemical synaptic input. Previously we demonstrated that the somatic membrane potential determines spike propagation within B21. Namely, B21 must be centrally depolarized if spikes are to propagate to an output process. We now demonstrate that this will occur with central depolarizations that are only a few millivolts. Depolarizations of this magnitude are not, however, sufficient to induce synaptic transmission to B8. B21-induced postsynaptic potentials (PSPs) are only observed if B21 is centrally depolarized by ≥10 mV. Larger depolarizations have a second impact on B21. They induce graded changes in the baseline intracellular calcium concentration that are virtually essential for the induction of chemical synaptic transmission. During motor programs, subthreshold depolarizations that increase calcium concentrations are observed during one of the two antagonistic phases of rhythmic activity. Chemical synaptic transmission from B21 to B8 is, therefore, likely to occur in a phase-dependent manner. Other neurons that receive mechanoafferent input are electrically coupled to B21. Differential control of spike propagation and chemical synaptic transmission may, therefore, represent a mechanism that permits selective control of afferent transmission to different types of neurons contacted by B21. Afferent transmission to neurons receiving chemical synaptic input will be phase specific, whereas transmission to electrically coupled followers will be phase independent. PMID:19605611

  14. Role of adenosine in the depolarization of hypoxic hamster diaphragm membrane in vitro.

    PubMed

    Esau, S A

    1994-04-01

    The resting membrane potential of in vitro hamster diaphragm muscle fibers is depolarized on exposure to hypoxia. It was hypothesized that this depolarization was mediated by adenosine. It was predicted that the treatment of well-oxygenated hamster diaphragm muscle strips in vitro with adenosine or adenosine agonists would depolarize the diaphragm fiber membrane. Furthermore, resting membrane potential of hypoxic diaphragm fibers would be repolarized by (1) the removal of adenosine by the enzyme adenosine deaminase (ADA), or (2) the addition of an adenosine antagonist, BW A1433. Adenosine (10(-4) M) depolarized the membrane by 8 +/- 1 mV (p < 0.001). The adenosine agonist cyclopentyladenosine, which has predominantly A1 receptor affinity, depolarized the membrane from -75.4 +/- 5.6 mV to -68.9 +/- 5.7 mV (p < 0.001). The A2 adenosine receptor agonist 5'-N-ethylcarboxamide adenosine did not cause a significant depolarization. The addition of ADA (2 unit/ml) to hypoxic muscle returned the resting membrane potential to that of well-oxygenated fibers, p < 0.001 versus hypoxia. BW A1433 (3 x 10(-7)) also restored the membrane potential of hypoxic muscle fibers from -72 +/- 1 mV to -79 +/- 1 mV (p < 0.001). These observations suggest that adenosine via the A1 adenosine receptor mediates the hypoxic depolarization of in vitro hamster diaphragm muscle. A direct effect of adenosine on muscle membrane has not been described previously.

  15. Mechanisms of GABA and glycine depolarization-induced calcium transients in rat dorsal horn neurons.

    PubMed Central

    Reichling, D B; Kyrozis, A; Wang, J; MacDermott, A B

    1994-01-01

    1. The mechanisms and effects of GABA- and glycine-evoked depolarization were studied in cultured rat dorsal horn neurons using indo-1 recordings of [Ca2+]i and patch clamp recordings in conventional whole-cell or perforated-patch mode. 2. Application of GABA to unclamped neurons caused [Ca2+]i increases that were dose dependent and exhibited GABAA receptor pharmacology. Calcium entered the neurons via high-threshold voltage-gated calcium channels (conotoxin and nimodipine sensitive). 3. In perforated-patch recordings employing cation-selective ionophores, GABAA receptor activation depolarized 123 of 132 cells to membrane potentials as depolarized as -33 mV (mean -50 mV in all 132 cells, +12 mV above resting potential). The ionic basis of the depolarization was determined by extracellular ion substitution; increased anionic conductance could account fully for the results. 4. Glycine, acting at a strychnine-sensitive receptor, also caused Ca2+ entry into these neurons through voltage-gated Ca2+ channels. Glycine and GABA both evoked [Ca2+]i responses in the same cells and the responses were highly correlated in amplitude. Glycine also depolarized all five cells tested with perforated recording. Each of the five cells was also depolarized by muscimol to a value similar to that obtained for glycine. 5. Both the depolarization and the increases in [Ca2+]i caused by GABA and glycine could potentially play a role in processes of development and differentiation and sensory transmission in the spinal cord dorsal horn. PMID:8057250

  16. Forest Loss in Protected Areas and Intact Forest Landscapes: A Global Analysis

    PubMed Central

    Heino, Matias; Kummu, Matti; Makkonen, Marika; Mulligan, Mark; Verburg, Peter H.; Jalava, Mika; Räsänen, Timo A.

    2015-01-01

    In spite of the high importance of forests, global forest loss has remained alarmingly high during the last decades. Forest loss at a global scale has been unveiled with increasingly finer spatial resolution, but the forest extent and loss in protected areas (PAs) and in large intact forest landscapes (IFLs) have not so far been systematically assessed. Moreover, the impact of protection on preserving the IFLs is not well understood. In this study we conducted a consistent assessment of the global forest loss in PAs and IFLs over the period 2000–2012. We used recently published global remote sensing based spatial forest cover change data, being a uniform and consistent dataset over space and time, together with global datasets on PAs’ and IFLs’ locations. Our analyses revealed that on a global scale 3% of the protected forest, 2.5% of the intact forest, and 1.5% of the protected intact forest were lost during the study period. These forest loss rates are relatively high compared to global total forest loss of 5% for the same time period. The variation in forest losses and in protection effect was large among geographical regions and countries. In some regions the loss in protected forests exceeded 5% (e.g. in Australia and Oceania, and North America) and the relative forest loss was higher inside protected areas than outside those areas (e.g. in Mongolia and parts of Africa, Central Asia, and Europe). At the same time, protection was found to prevent forest loss in several countries (e.g. in South America and Southeast Asia). Globally, high area-weighted forest loss rates of protected and intact forests were associated with high gross domestic product and in the case of protected forests also with high proportions of agricultural land. Our findings reinforce the need for improved understanding of the reasons for the high forest losses in PAs and IFLs and strategies to prevent further losses. PMID:26466348

  17. Forest Loss in Protected Areas and Intact Forest Landscapes: A Global Analysis.

    PubMed

    Heino, Matias; Kummu, Matti; Makkonen, Marika; Mulligan, Mark; Verburg, Peter H; Jalava, Mika; Räsänen, Timo A

    2015-01-01

    In spite of the high importance of forests, global forest loss has remained alarmingly high during the last decades. Forest loss at a global scale has been unveiled with increasingly finer spatial resolution, but the forest extent and loss in protected areas (PAs) and in large intact forest landscapes (IFLs) have not so far been systematically assessed. Moreover, the impact of protection on preserving the IFLs is not well understood. In this study we conducted a consistent assessment of the global forest loss in PAs and IFLs over the period 2000-2012. We used recently published global remote sensing based spatial forest cover change data, being a uniform and consistent dataset over space and time, together with global datasets on PAs' and IFLs' locations. Our analyses revealed that on a global scale 3% of the protected forest, 2.5% of the intact forest, and 1.5% of the protected intact forest were lost during the study period. These forest loss rates are relatively high compared to global total forest loss of 5% for the same time period. The variation in forest losses and in protection effect was large among geographical regions and countries. In some regions the loss in protected forests exceeded 5% (e.g. in Australia and Oceania, and North America) and the relative forest loss was higher inside protected areas than outside those areas (e.g. in Mongolia and parts of Africa, Central Asia, and Europe). At the same time, protection was found to prevent forest loss in several countries (e.g. in South America and Southeast Asia). Globally, high area-weighted forest loss rates of protected and intact forests were associated with high gross domestic product and in the case of protected forests also with high proportions of agricultural land. Our findings reinforce the need for improved understanding of the reasons for the high forest losses in PAs and IFLs and strategies to prevent further losses.

  18. Quantifying the polarization properties of non-depolarizing optical elements with virtual distorting elements.

    PubMed

    Wang, Xiao; Yang, Feng; Yin, Jianhua

    2017-04-01

    It is well known that polarization can be potentially distorted by optical elements in optical paths, which intensively influences researches and techniques related to polarization analysis. For this, we proposed to exactly quantify the polarization properties of non-depolarizing optical elements with virtual distorting elements characterized by three parameters: orientation Θ, diattenuation Γ, and retardation Δ. Utilizing the least-squares fitting method, these three parameters can be determined by fitting the measured output polarization states from the optical element with the polarization responses of VDEs. The principle of this method is detailed, and a corresponding experimental setup is further presented. The feasibility of this method has been verified in reflective mirrors and a dichroic mirror. Based on the quantification results with our setup, we have successfully compensated the polarization distortion induced by a dichroic mirror. The precision of this method has been investigated in detail with Monte Carlo simulations. The investigation results show that this method has high precision at certain measurement conditions, and the precision can be further improved.

  19. α-Synuclein expression is induced by depolarization and cyclic AMP in enteric neurons.

    PubMed

    Paillusson, Sébastien; Tasselli, Maddalena; Lebouvier, Thibaud; Mahé, Maxime Michaël; Chevalier, Julien; Biraud, Mandy; Cario-Toumaniantz, Chystelle; Neunlist, Michel; Derkinderen, Pascal

    2010-11-01

    Accumulated evidence emphasizes the importance of α-synuclein expression levels in Parkinson's disease (PD) pathogenesis. PD is a multicentric disorder that affects the enteric nervous system (ENS), whose involvement may herald the degenerative process in the CNS. We therefore undertook the present study to investigate the mechanisms involved in the regulation of expression of α-synuclein in the ENS. The regulation of α-synuclein expression was assessed by qPCR and western blot analysis in rat primary culture of ENS treated with KCl and forskolin. A pharmacological approach was used to decipher the signaling pathways involved. Intraperitoneal injections of Bay K-8644 and forskolin were performed in mice, whose proximal colons were further analyzed for α-synuclein expression. Depolarization and forskolin increased α-synuclein mRNA and protein expression in primary cultures of ENS, although L-type calcium channel and protein kinase A, respectively. Both stimuli increased α-synuclein expression through a Ras/extracellular signal-regulated kinases pathway. An increase in α-synuclein expression was also observed in vivo in the ENS of mice injected with Bay K-8644 or forskolin. In conclusion, we have identified stimuli leading to α-synuclein over-expression in the ENS, which could be critical in the initiation of the pathological process in PD.

  20. Apricot Melanoidins Prevent Oxidative Endothelial Cell Death by Counteracting Mitochondrial Oxidation and Membrane Depolarization

    PubMed Central

    Giordo, Roberta; Emanueli, Costanza; Sanguinetti, Anna Maria; Piscopo, Amalia; Poiana, Marco; Capobianco, Giampiero; Piga, Antonio; Pintus, Gianfranco

    2012-01-01

    The cardiovascular benefits associated with diets rich in fruit and vegetables are thought to be due to phytochemicals contained in fresh plant material. However, whether processed plant foods provide the same benefits as unprocessed ones is an open question. Melanoidins from heat-processed apricots were isolated and their presence confirmed by colorimetric analysis and browning index. Oxidative injury of endothelial cells (ECs) is the key step for the onset and progression of cardiovascular diseases (CVD), therefore the potential protective effect of apricot melanoidins on hydrogen peroxide-induced oxidative mitochondrial damage and cell death was explored in human ECs. The redox state of cytoplasmic and mitochondrial compartments was detected by using the redox-sensitive, fluorescent protein (roGFP), while the mitochondrial membrane potential (MMP) was assessed with the fluorescent dye, JC-1. ECs exposure to hydrogen peroxide, dose-dependently induced mitochondrial and cytoplasmic oxidation. Additionally detected hydrogen peroxide-induced phenomena were MMP dissipation and ECs death. Pretreatment of ECs with apricot melanoidins, significantly counteracted and ultimately abolished hydrogen peroxide-induced intracellular oxidation, mitochondrial depolarization and cell death. In this regard, our current results clearly indicate that melanoidins derived from heat-processed apricots, protect human ECs against oxidative stress. PMID:23144984

  1. Distinct spatiotemporal patterns of spreading depolarizations during early infarct evolution: evidence from real-time imaging

    PubMed Central

    Kumagai, Tetsuya; Walberer, Maureen; Nakamura, Hajime; Endepols, Heike; Sué, Michael; Vollmar, Stefan; Adib, Sasan; Mies, Günter; Yoshimine, Toshiki; Schroeter, Michael; Graf, Rudolf

    2011-01-01

    Experimental and clinical studies indicate that waves of cortical spreading depolarization (CSD) appearing in the ischemic penumbra contribute to secondary lesion growth. We used an embolic stroke model that enabled us to investigate inverse coupling of blood flow by laser speckle imaging (CBFLSF) to CSD as a contributing factor to lesion growth already in the early phase after arterial occlusion. Embolization by macrospheres injected into the left carotid artery of anesthetized rats reduced CBFLSF in the territories of the middle cerebral artery (MCA) (8/14 animals), the posterior cerebral artery (PCA) (2/14) or in less clearly defined regions (4/14). Analysis of MCA occlusions (MCAOs) revealed a first CSD wave starting off during ischemic decline at the emerging core region, propagating concentrically over large portions of left cortex. Subsequent recurrent waves of CSD did not propagate concentrically but preferentially circled around the ischemic core. In the vicinity of the core region, CSDs were coupled to waves of predominantly vasoconstrictive CBFLSF responses, resulting in further decline of CBF in the entire inner penumbra and in expansion of the ischemic core. We conclude that CSDs and corresponding CBF responses follow a defined spatiotemporal order, and contribute to early evolution of ischemic territories. PMID:20700132

  2. Depolarizing differential Mueller matrix of homogeneous media under Gaussian fluctuation hypothesis.

    PubMed

    Devlaminck, Vincent

    2015-10-01

    In this paper, we address the issue of the existence of a solution of depolarizing differential Mueller matrix for a homogeneous medium. Such a medium is characterized by linear changes of its differential optical properties with z the thickness of the medium. We show that, under a short correlation distance assumption, it is possible to derive such linear solution, and we clarify this solution in the particular case where the random fluctuation processes associated to the optical properties are Gaussian white noise-like. A solution to the problem of noncommutativity of a previously proposed model [J. Opt. Soc. Am.30, 2196 (2013)JOSAAH0030-394110.1364/JOSAA.30.002196] is given by assuming a random permutation of the order of the layers and by averaging all the differential matrices resulting from these permutations. It is shown that the underlying assumption in this case is exactly the Gaussian white noise assumption. Finally, a recently proposed approach [Opt. Lett.39, 4470 (2014)OPLEDP0146-959210.1364/OL.39.004470] for analysis of the statistical properties related to changes in optical properties is revisited, and the experimental conditions of application of these results are specified.

  3. Low temperature dielectric relaxation of poly (L-lactic acid) (PLLA) by Thermally Stimulated Depolarization Current

    NASA Astrophysics Data System (ADS)

    Mishra Patidar, Manju; Jain, Deepti; Nath, R.; Ganesan, V.

    2016-10-01

    Poly (L-lactic acid) (PLLA) is a biodegradable and biocompatible polyester that can be produced by renewable resources, like corn. Being non-toxic to human body, PLLA is used in biomedical applications, like surgical sutures, bone fixation devices, or controlled drug delivery. Besides its application studies, very few experiments have been done to study its dielectric relaxation in the low temperature region. Keeping this in mind we have performed a low temperature thermally stimulated depolarization current (TSDC) studies over the temperature range of 80K-400K to understand the relaxation phenomena of PLLA. We could observe a multi modal broad relaxation of small but significant intensity at low temperatures while a sharp and high intense peak around glass transition temperature, Tg∼ 333K, of PLLA has appeared. The fine structure of the low temperature TSDC peak may be attributed to the spherulites formation of crystallite regions inter twinned with the polymer as seen in AFM and appear to be produced due to an isothermal crystallization process. XRD analysis also confirms the semicrystalline nature of the PLLA film.

  4. Analysis of turbomachine viscous losses affected by changes in blade geometry

    NASA Technical Reports Server (NTRS)

    Miser, James W; Stewart, Warner L; Whitney, Warren J

    1956-01-01

    The effect of changes in blade geometry on the viscous losses in turbomachines is analyzed. The viscous losses can be expressed as a function of three variables: the blade height-to spacing ratio, the solidity, and a blade-height Reynolds number. A method of optimizing the number of blades and the solidity is given. The effect of trailing-edge blockage on blade loss and its effect on the choice of blade number for a particular design are also discussed.

  5. Losing Weight on Reality TV: A Content Analysis of the Weight Loss Behaviors and Practices Portrayed on The Biggest Loser.

    PubMed

    Klos, Lori A; Greenleaf, Christy; Paly, Natalie; Kessler, Molly M; Shoemaker, Colby G; Suchla, Erika A

    2015-01-01

    A number of weight loss-related reality television programs chronicle the weight loss experience of obese individuals in a competitive context. Although highly popular, such shows may misrepresent the behavior change necessary to achieve substantial weight loss. A systematic, quantitative content analysis of Seasons 10-13 (n = 66 episodes) of The Biggest Loser was conducted to determine the amount of time and number of instances that diet, physical activity, or other weight management strategies were presented. The average episode was 78.8 ± 15.7 min in length. Approximately 33.3% of an episode, representing 1,121 segments, portrayed behavioral weight management-related content. Within the episode time devoted to weight management content, 85.2% was related to physical activity, 13.5% to diet, and 1.2% to other. Recent seasons of The Biggest Loser suggest that substantial weight loss is achieved primarily through physical activity, with little emphasis on modifying diet and eating behavior. Although physical activity can impart substantial metabolic health benefits, it may be difficult to create enough of an energy deficit to induce significant weight loss in the real world. Future studies should examine the weight loss attitudes and behaviors of obese individuals and health professionals after exposure to reality television shows focused on weight loss.

  6. Elements loss analysis based on spectral diagnosis in laser-arc hybrid welding of aluminum alloy

    NASA Astrophysics Data System (ADS)

    Chen, Yong; Chen, Hui; Zhu, Minhao; Yang, Tao; Shen, Lin

    2017-07-01

    Aluminum alloy has been widely used in automobiles, high-speed trains, aerospace and many other fields. The loss of elements during welding process causes welding defects and affects the microstructure and properties of the joints. This paper discusses the correlation between welding process, spectral intensity and loss of elements in laser-arc hybrid welding of Al alloys. The results show that laser power and arc current have a significant impact on the spectral intensity and loss of elements. Compared with the base metal, the contents of alloying elements in the weld area are lower. The burning losses of alloy elements increase with the welding heat input.

  7. Motivation for Participating in a Weight Loss Program and Financial Incentives: An Analysis from a Randomized Trial

    PubMed Central

    Crane, Melissa M.; Tate, Deborah F.; Finkelstein, Eric A.; Linnan, Laura A.

    2012-01-01

    This analysis investigated if changes in autonomous or controlled motivation for participation in a weight loss program differed between individuals offered a financial incentive for weight loss compared to individuals not offered an incentive. Additionally, the same relationships were tested among those who lost weight and either received or did not receive an incentive. This analysis used data from a year-long randomized worksite weight loss program that randomly assigned employees in each worksite to either a low-intensity weight loss program or the same program plus small financial incentives for weight loss ($5.00 per percentage of initial weight lost). There were no differences in changes between groups on motivation during the study, however, increases in autonomous motivation were consistently associated with greater weight losses. This suggests that the small incentives used in this program did not lead to increases in controlled motivation nor did they undermine autonomous motivation. Future studies are needed to evaluate the magnitude and timing of incentives to more fully understand the relationship between incentives and motivation. PMID:22577524

  8. Motivation for participating in a weight loss program and financial incentives: an analysis from a randomized trial.

    PubMed

    Crane, Melissa M; Tate, Deborah F; Finkelstein, Eric A; Linnan, Laura A

    2012-01-01

    This analysis investigated if changes in autonomous or controlled motivation for participation in a weight loss program differed between individuals offered a financial incentive for weight loss compared to individuals not offered an incentive. Additionally, the same relationships were tested among those who lost weight and either received or did not receive an incentive. This analysis used data from a year-long randomized worksite weight loss program that randomly assigned employees in each worksite to either a low-intensity weight loss program or the same program plus small financial incentives for weight loss ($5.00 per percentage of initial weight lost). There were no differences in changes between groups on motivation during the study, however, increases in autonomous motivation were consistently associated with greater weight losses. This suggests that the small incentives used in this program did not lead to increases in controlled motivation nor did they undermine autonomous motivation. Future studies are needed to evaluate the magnitude and timing of incentives to more fully understand the relationship between incentives and motivation.

  9. Tunable depolarized light scattering from gold and gold/silver nanorods.

    PubMed

    Khlebtsov, Boris; Khanadeev, Vitaly; Khlebtsov, Nikolai

    2010-04-07

    We combine the fabrication of Au and Au/Ag core/shell nanorods (NRs), as well as experimental measurements of vis-NIR extinction, unpolarized, and cross-polarized light scattering spectra, with T-matrix and separation-of-variables simulations, to gain insight into the relation between the morphology/composition of nanoparticles and their isotropic and anisotropic optical responses. Using several Au and Au/Ag core/shell NR samples, we present unambiguous experimental evidence of a tunable correlation between the longitudinal plasmon resonances of NRs and their spectral depolarization maxima. For gold NRs, the depolarization maxima follow the extinction plasmon resonances blue-shifted from 80 to 270 nm. In contrast, the depolarization maximum of Au/Ag NRs is located just near the longitudinal resonance, and the spectral shift of the depolarization maximum is about 10 to 20 nm. The experimental extinction and depolarization spectra of gold NRs are in good agreement with T-matrix simulations based on TEM-fitted models that account for the aspect ratio polydispersity and byproduct contributions. For composite Au/Ag NRs, the separation-of-variables simulations provide a calibration curve that correlates the relative spectral shift of the extinction resonance with the silver shell thicknesses and generates experimental data that are in good agreement with estimations based on the Ag/Au mass ratio.

  10. Quantitative correlation between light depolarization and transport albedo of various porcine tissues.

    PubMed

    Alali, Sanaz; Ahmad, Manzoor; Kim, Anthony; Vurgun, Nasit; Wood, Michael F G; Vitkin, I Alex

    2012-04-01

    We present a quantitative study of depolarization in biological tissues and correlate it with measured optical properties (reduced scattering and absorption coefficients). Polarized light imaging was used to examine optically thick samples of both isotropic (liver, kidney cortex, and brain) and anisotropic (cardiac muscle, loin muscle, and tendon) pig tissues in transmission and reflection geometries. Depolarization (total, linear, and circular), as derived from polar decomposition of the measured tissue Mueller matrix, was shown to be related to the measured optical properties. We observed that depolarization increases with the transport albedo for isotropic and anisotropic tissues, independent of measurement geometry. For anisotropic tissues, depolarization was higher compared to isotropic tissues of similar transport albedo, indicating birefringence-caused depolarization effects. For tissues with large transport albedos (greater than ~0.97), backscattering geometry was preferred over transmission due to its greater retention of light polarization; this was not the case for tissues with lower transport albedo. Preferential preservation of linearly polarized light over circularly polarized light was seen in all tissue types and all measurement geometries, implying the dominance of Rayleigh-like scattering. The tabulated polarization properties of different tissue types and their links to bulk optical properties should prove useful in future polarimetric tissue characterization and imaging studies.

  11. Mechanism of blue-light-induced plasma-membrane depolarization in etiolated cucumber hypocotyls

    NASA Technical Reports Server (NTRS)

    Spalding, E. P.; Cosgrove, D. J.

    1992-01-01

    A large, transient depolarization of the plasma membrane precedes the rapid blue-light (BL)-induced growth suppression in etiolated seedlings of Cucumis sativus L. The mechanism of this voltage transient was investigated by applying inhibitors of ion channels and the plasma-membrane H(+)-ATPase, by manipulating extracellular ion concentrations, and by measuring cell input resistance and ATP levels. The depolarizing phase was not affected by Ca(2+)-channel blockers (verapamil, La3+) or by reducing extracellular free Ca2+ by treatment with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). However, these treatments did reduce the rate of repolarization, indicating an inward movement of Ca2+ is involved. No effects of the K(+)-channel blocker tetraethylammonium (TEA+) were detected. Vanadate and KCN, used to inhibit the H(+)-ATPase, reduced or completely inhibited the BL-induced depolarization. Levels of ATP increased by 11-26% after 1-2 min of BL. Input resistance of trichrome cells, measured with double-barreled microelectrodes, remained constant during the onset of the depolarization but decreased as the membrane voltage became more positive than -90 mV. The results indicate that the depolarization mechanism initially involves inactivation of the H(+)-ATPase with subsequent transient activation of one or more types of ion channels.

  12. Dopamine modulates an intrinsic mGluR5-mediated depolarization underlying prefrontal persistent activity

    PubMed Central

    Sidiropoulou, Kyriaki; Lu, Fang-Min; Fowler, Melissa A.; Xiao, Rui; Phillips, Christopher; Ozkan, Emin D.; Zhu, Michael X.; White, Francis J.; Cooper, Donald C.

    2009-01-01

    Intrinsic properties of neurons that enable them to maintain depolarized, persistently activated states in the absence of sustained input are poorly understood. In short-term memory tasks, individual prefrontal cortical (PFC) neurons are capable of maintaining persistent action potential output during delay periods between informative cues and behavioral responses. Dopamine and drugs of abuse alter PFC function and working memory possibly by modulating intrinsic neuronal properties. Here we use patch-clamp recording of layer 5 PFC pyramidal neurons to identify an action potential burst-evoked intrinsic mGluR5-mediated postsynaptic depolarization that initiates an activated state. Depolarization occurs in the absence of recurrent synaptic activity and is reduced by a postsynaptic dopamine D1/5 receptor pathway. The depolarization is substantially diminished following behavioral sensitization to cocaine; moreover the D1/5 receptor modulation is lost. We propose the burst-evoked intrinsic depolarization to be a novel form of short-term cellular memory that is modulated by dopamine and cocaine experience. PMID:19169252

  13. Developmental roles of the spontaneous depolarization wave in synaptic network formation in the embryonic brainstem.

    PubMed

    Momose-Sato, Yoko; Sato, Katsushige

    2017-09-23

    One of the earliest activities expressed within the developing central nervous system is a widely propagating wave-like activity, which we referred to as the depolarization wave. Despite considerable consensus concerning the global features of the activity, its physiological role is yet to be clarified. The depolarization wave is expressed during a specific period of functional synaptogenesis, and this developmental profile has led to the hypothesis that the wave plays some roles in synaptic network organization. In the present study, we tested this hypothesis by inhibiting the depolarization wave in ovo and examining its effects on the development of functional synapses in vagus nerve-related brainstem nuclei of the chick embryo. Chronic inhibition of the depolarization wave had no significant effect on the developmental time course, amplitude, and spatial distribution of monosynaptic excitatory postsynaptic potentials in the first-order nuclei of the vagal sensory pathway (the nucleus of the tractus solitarius (NTS) and the contralateral non-NTS region), but reduced polysynaptic responses in the higher order nucleus (the parabrachial nucleus). These results suggest that the depolarization wave plays an important role in the initial process of functional synaptic expression in the brainstem, especially in the higher order nucleus of the cranial sensory pathway. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  14. Mechanism of blue-light-induced plasma-membrane depolarization in etiolated cucumber hypocotyls

    NASA Technical Reports Server (NTRS)

    Spalding, E. P.; Cosgrove, D. J.

    1992-01-01

    A large, transient depolarization of the plasma membrane precedes the rapid blue-light (BL)-induced growth suppression in etiolated seedlings of Cucumis sativus L. The mechanism of this voltage transient was investigated by applying inhibitors of ion channels and the plasma-membrane H(+)-ATPase, by manipulating extracellular ion concentrations, and by measuring cell input resistance and ATP levels. The depolarizing phase was not affected by Ca(2+)-channel blockers (verapamil, La3+) or by reducing extracellular free Ca2+ by treatment with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA). However, these treatments did reduce the rate of repolarization, indicating an inward movement of Ca2+ is involved. No effects of the K(+)-channel blocker tetraethylammonium (TEA+) were detected. Vanadate and KCN, used to inhibit the H(+)-ATPase, reduced or completely inhibited the BL-induced depolarization. Levels of ATP increased by 11-26% after 1-2 min of BL. Input resistance of trichrome cells, measured with double-barreled microelectrodes, remained constant during the onset of the depolarization but decreased as the membrane voltage became more positive than -90 mV. The results indicate that the depolarization mechanism initially involves inactivation of the H(+)-ATPase with subsequent transient activation of one or more types of ion channels.

  15. Dicarbocyanine dyes in methanol solution probed by depolarized Rayleigh and hyper-Rayleigh light scattering

    NASA Astrophysics Data System (ADS)

    Song, Ok-Keun; Wang, C. H.

    1996-06-01

    The hyper-Rayleigh scattering (HRS) intensity of two symmetric carbocyanine dyes (1122 DEDC and 1144 DEDC, full names given in the text) in methanol is measured as a function of dye concentration. These dye molecules at equilibrium show a negligible permanent dipole moment. The low concentration data showing that the HRS intensity is proportional to the dye concentration are used to determine the first hyperpolarizability for each of these dyes. However, above a concentration ρb=0.1×10-3 M, the HRS intensity shows an anomalous concentration dependence. Above ρb, the HRS intensity shows a saturation behavior and it even decreases with increasing concentration at high dye concentration. The depolarization ratio of the HRS intensity is also measured as a function of dye concentration. At lowest concentration, the depolarization ratio is 0.18. As the dye concentration increases, the depolarization ratio also rapidly increases but the increase quickly saturates as the concentration exceeds ρb. The concentration dependence of the HRS intensity and depolarization ratio are interpreted as due to formation of molecular aggregates. The depolarized Rayleigh scattering (DRS) intensity is also measured as a function of dye concentration. The result of DRS corroborates well with that found in HRS.

  16. Mechanisms underlying short-term modulation of transmitter release by presynaptic depolarization

    PubMed Central

    Hori, Tetsuya; Takahashi, Tomoyuki

    2009-01-01

    Presynaptic terminal depolarization modulates the efficacy of transmitter release. Residual Ca2+ remaining after presynaptic depolarization is thought to play a critical role in facilitation of transmitter release, but its downstream mechanism remains unclear. By making simultaneous pre- and postsynaptic recordings at the rodent calyx of Held synapse, we have investigated mechanisms involved in the facilitation and depression of postsynaptic currents induced by presynaptic depolarization. In voltage-clamp experiments, cancellation of the Ca2+-dependent presynaptic Ca2+ current (IpCa) facilitation revealed that this mechanism can account for 50% of postsynaptic current facilitation, irrespective of intraterminal EGTA concentrations. Intraterminal EGTA, loaded at 10 mm, failed to block postsynaptic current facilitation, but additional BAPTA at 1 mm abolished it. Potassium-induced sustained depolarization of non-dialysed presynaptic terminals caused a facilitation of postsynaptic currents, superimposed on a depression, with the latter resulting from reductions in presynaptic action potential amplitude and number of releasable vesicles. We conclude that presynaptic depolarization bidirectionally modulates transmitter release, and that the residual Ca2+ mechanism for synaptic facilitation operates in the immediate vicinity of voltage-gated Ca2+ channels in the nerve terminal. PMID:19403620

  17. Influence of ambient temperature variations on the performance of Lyot depolarizers

    NASA Astrophysics Data System (ADS)

    Redek, M.; Makowski, P. L.; Domanski, A. W.

    2013-10-01

    The influence of temperature on the efficiency of Lyot depolarizers is analysed. It is a commonly used idealization that if the birefringent sections forming the depolarizer are made long enough with respect to the coherence time of the lightwave then strictly complete depolarization is always assured. This can lead to a false conclusion that in a real-world system the residual degree of polarization (DoP) will reach a certain value, slightly higher than zero, and remain independent of the initial polarization state (SoP) and insensitive for small variations of material parameters. We point out that Lyot depolarizers are always inhomogeneous in general and, thus, a precise estimation of the maximum possible DoP of an emerging lighwave is not trivial. Using a system made of two sections of lithium niobate we examine and explain how environmental temperature variations within the range of 1 ° C can significantly affect the depolarization efficiency. The numerical predictions of the effect have been verified qualitatively in experiments.

  18. [Cardiac electric field at the period of depolarization and repolarization of the frog heart ventricle].

    PubMed

    Vaĭkshnoraĭte, M A; Belogolova, A S; Vitiazev, V A; Azarov, Ia E; Shmakov, D N

    2008-01-01

    Multichannel mapping of electrical field on heart ventricle epicardium and the body surface in frogs Rana esculenta and Rana temporaria was performed at periods of the ventricular myocardium depolarization and repolarization. The zone of the epicardium early depolarization is located on epicardium of the ventricle base posterior wall, while the late depolarization zone--on its apex and on the base anterior wall. The total vector of sequence of the ventricle epicardium depolarization is directed from the base to the apex. The zone of the early repolarization is located in the apical area, while that of the late one--in the area of the base. On the frog body surface the cardioelectric field with the cranial zone of negative and the caudal zone of positive potentials is formed before the appearance of the QRS complex on ECG. At the period of the heart ventricle repolarization the zone of the cardioelectric field negative potentials is located in the cranial, while that of the positive ones--in the body surface caudal parts. The cardioelectric field on the frog body surface at the periods of depolarization and repolarization of the ventricle myocardium reflects adequately the projection of sequence of involvement with excitation and of distribution of potentials on epicardium.

  19. Energy transfer and depolarization in the photoluminescence of a plasmonic molecule.

    PubMed

    Yin, Tingting; Jiang, Liyong; Dong, Zhaogang; Yang, Joel K W; Shen, Ze Xiang

    2017-02-02

    We report a comprehensive experimental study of the polarization dependence between excitation and photoluminescence (PL) emission from single dolmen-like metallic nanostructures that exhibit both Fano-like and Lorentz-like plasmon resonances. Though the PL spectra of this plasmonic "molecule" also exhibit the Fano and Lorentz signature, the emitted photons do not maintain the same polarization as the excitation. Surprisingly, the degree of depolarization correlates closely to the resonant excitation of the constituent atoms (single nanorod). More specifically, the excitation of a transverse plasmon mode results in a depolarized emission through the longitudinal plasmon modes of the constituent nanorods. In view of the recent evidence of on-resonant plasmon induced excitations in generating hot electrons, our results suggest that depolarized PL emissions could be enhanced through hot-electron decay. Both macroscopic and microscopic mechanisms are proposed to well-understand the excitation wavelength dependent depolarized photoluminescence behaviors in the plasmonic molecule. Our results lay a foundation for applying the depolarized photoluminescence of complex plasmonic nanostructures in polarization engineering.

  20. Visualization analysis of research frontiers and trends in nerve regeneration and osseoperception in the repair of tooth loss.

    PubMed

    Zhang, Xiaoge; Tang, Tian; Zhao, Zhihe; Zheng, Leilei; Ding, Yin

    2014-11-15

    This study analyzed 85 articles indexed by the Web of Science concerning nerve regeneration and osseoperception during tooth loss repair. Using the Web of Science database and Citespace III software, a document co-citation network map was drawn by document co-citation analysis and word frequency analysis methods. Combined with emergent node secondary literature retrieval, subject headings with apparent changing word frequency trends were retrieved so as to identify research frontiers and development trends. Research frontiers and hotspots for neuronal calcium sensor protein were quantitatively explored to forecast future research developments in nerve regeneration and osseoperception during repair of tooth loss.

  1. Mapping and uncertainty analysis of energy and pitch angle phase space in the DIII-D fast ion loss detector

    SciTech Connect

    Pace, D. C. Fisher, R. K.; Van Zeeland, M. A.; Pipes, R.

    2014-11-15

    New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signature spanning across 50-140 keV. These calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.

  2. Mapping and uncertainty analysis of energy and pitch angle phase space in the DIII-D fast ion loss detector

    DOE PAGES

    Pace, D. C.; Pipes, R.; Fisher, R. K.; ...

    2014-08-05

    New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signaturemore » spanning across 50-140 keV. As a result, these calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.« less

  3. Mapping and uncertainty analysis of energy and pitch angle phase space in the DIII-D fast ion loss detector

    SciTech Connect

    Pace, D. C.; Pipes, R.; Fisher, R. K.; Van Zeeland, M. A.

    2014-08-05

    New phase space mapping and uncertainty analysis of energetic ion loss data in the DIII-D tokamak provides experimental results that serve as valuable constraints in first-principles simulations of energetic ion transport. Beam ion losses are measured by the fast ion loss detector (FILD) diagnostic system consisting of two magnetic spectrometers placed independently along the outer wall. Monte Carlo simulations of mono-energetic and single-pitch ions reaching the FILDs are used to determine the expected uncertainty in the measurements. Modeling shows that the variation in gyrophase of 80 keV beam ions at the FILD aperture can produce an apparent measured energy signature spanning across 50-140 keV. As a result, these calculations compare favorably with experiments in which neutral beam prompt loss provides a well known energy and pitch distribution.

  4. Single-Nucleotide Polymorphism-Microarray Ploidy Analysis of Paraffin-Embedded Products of Conception in Recurrent Pregnancy Loss Evaluations.

    PubMed

    Maslow, Bat-Sheva L; Budinetz, Tara; Sueldo, Carolina; Anspach, Erica; Engmann, Lawrence; Benadiva, Claudio; Nulsen, John C

    2015-07-01

    To compare the analysis of chromosome number from paraffin-embedded products of conception using single-nucleotide polymorphism (SNP) microarray with the recommended screening for the evaluation of couples presenting with recurrent pregnancy loss who do not have previous fetal cytogenetic data. We performed a retrospective cohort study including all women who presented for a new evaluation of recurrent pregnancy loss over a 2-year period (January 1, 2012, to December 31, 2013). All participants had at least two documented first-trimester losses and both the recommended screening tests and SNP microarray performed on at least one paraffin-embedded products of conception sample. Single-nucleotide polymorphism microarray identifies all 24 chromosomes (22 autosomes, X, and Y). Forty-two women with a total of 178 losses were included in the study. Paraffin-embedded products of conception from 62 losses were sent for SNP microarray. Single-nucleotide polymorphism microarray successfully diagnosed fetal chromosome number in 71% (44/62) of samples, of which 43% (19/44) were euploid and 57% (25/44) were noneuploid. Seven of 42 (17%) participants had abnormalities on recurrent pregnancy loss screening. The per-person detection rate for a cause of pregnancy loss was significantly higher in the SNP microarray (0.50; 95% confidence interval [CI] 0.36-0.64) compared with recurrent pregnancy loss evaluation (0.17; 95% CI 0.08-0.31) (P=.002). Participants with one or more euploid loss identified on paraffin-embedded products of conception were significantly more likely to have an abnormality on recurrent pregnancy loss screening than those with only noneuploid results (P=.028). The significance remained when controlling for age, number of losses, number of samples, and total pregnancies. These results suggest that SNP microarray testing of paraffin-embedded products of conception is a valuable tool for the evaluation of recurrent pregnancy loss in patients without prior fetal

  5. Global analysis of plasticity in turgor loss point, a key drought tolerance trait.

    PubMed

    Bartlett, Megan K; Zhang, Ya; Kreidler, Nissa; Sun, Shanwen; Ardy, Rico; Cao, Kunfang; Sack, Lawren

    2014-12-01

    Many species face increasing drought under climate change. Plasticity has been predicted to strongly influence species' drought responses, but broad patterns in plasticity have not been examined for key drought tolerance traits, including turgor loss or 'wilting' point (πtlp ). As soil dries, plants shift πtlp by accumulating solutes (i.e. 'osmotic adjustment'). We conducted the first global analysis of plasticity in Δπtlp and related traits for 283 wild and crop species in ecosystems worldwide. Δπtlp was widely prevalent but moderate (-0.44 MPa), accounting for 16% of post-drought πtlp. Thus, pre-drought πtlp was a considerably stronger predictor of post-drought πtlp across species of wild plants. For cultivars of certain crops Δπtlp accounted for major differences in post-drought πtlp. Climate was correlated with pre- and post-drought πtlp, but not Δπtlp. Thus, despite the wide prevalence of plasticity, πtlp measured in one season can reliably characterise most species' constitutive drought tolerances and distributions relative to water supply. © 2014 John Wiley & Sons Ltd/CNRS.

  6. Aircraft Loss of Control: Problem Analysis for the Development and Validation of Technology Solutions

    NASA Technical Reports Server (NTRS)

    Belcastro, Christine M.; Newman, Richard L.; Crider, Dennis A.; Klyde, David H.; Foster, John V.; Groff, Loren

    2016-01-01

    Aircraft loss of control (LOC) is a leading cause of fatal accidents across all transport airplane and operational classes. LOC can result from a wide spectrum of precursors (or hazards), often occurring in combination. Technologies developed for LOC prevention and recovery must therefore be effective under a wide variety of conditions and uncertainties, including multiple hazards, and the validation process must provide a means of assessing system effectiveness and coverage of these hazards. This paper provides a detailed description of a methodology for analyzing LOC as a dynamics and control problem for the purpose of developing effective technology solutions. The paper includes a definition of LOC based on several recent publications, a detailed description of a refined LOC accident analysis process that is illustrated via selected example cases, and a description of planned follow-on activities for identifying future potential LOC risks and the development of LOC test scenarios. Some preliminary considerations for LOC of Unmanned Aircraft Systems (UAS) and for their safe integration into the National Airspace System (NAS) are also discussed.

  7. Uplink Scheduling and Adjacent-Channel Coupling Loss Analysis for TD-LTE Deployment

    PubMed Central

    Yeo, Woon-Young; Moon, Sung Ho

    2014-01-01

    TD-LTE, one of the two duplexing modes in LTE, operates in unpaired spectrum and has the advantages of TDD-based technologies. It is expected that TD-LTE will be more rapidly deployed in near future and most of WiMax operators will upgrade their networks to TD-LTE gradually. Before completely upgrading to TD-LTE, WiMax may coexist with TD-LTE in an adjacent frequency band. In addition, multiple TD-LTE operators may deploy their networks in adjacent bands. When more than one TDD network operates in adjacent frequency bands, severe interference may happen due to adjacent channel interference (ACI) and unsynchronized operations. In this paper, coexistence issues between TD-LTE and other systems are analyzed and coexistence requirements are provided. This paper has three research objectives. First, frame synchronization between TD-LTE and WiMax is discussed by investigating possible combinations of TD-LTE and WiMax configurations. Second, an uplink scheduling algorithm is proposed to utilize a leakage pattern of ACI in synchronized operations. Third, minimum requirements for coexistence in unsynchronized operations are analyzed by introducing a concept of adjacent-channel coupling loss. From the analysis and simulation results, we can see that coexistence of TD-LTE with other TDD systems is feasible if the two networks are synchronized. For the unsynchronized case, some special cell-site engineering techniques may be required to reduce the ACI. PMID:24707214

  8. Ares I-X First Flight Loss of Vehicle Probability Analysis

    NASA Technical Reports Server (NTRS)

    Bigler, Mark A.; Cross, Robert B.; Osborn, John H.; Li, Yunnhon

    2011-01-01

    As part of the Constellation (Cx) Program development effort, several test flights were planned to prove concepts and operational capabilities of the new vehicles being developed. The first test, involving the Eastern Test Range, is the Ares I-X launched in 2009. As part of this test, the risk to the general public was addressed to ensure it is within Air Force requirements. This paper describes the methodology used to develop first flight estimates of overall loss of vehicle (LOV) failure probability, specifically for the Ares I-X. The method described in this report starts with the Air Force s generic failure probability estimate for first flight and adjusts the value based on the complexity of the vehicle as compared to the complexity of a generic vehicle. The results estimate a 1 in 9 probability of failure. The paper also describes traditional PRA methods used in this assessment, which were then combined with the updated first flight risk methodology to generate inputs required by the malfunction turn analysis to support estimate of casualty (Ec) calculations as part of the Final Flight Data Package (FFDP) delivered to the Eastern Range for Final Flight Plan Approval.

  9. Regulatory analysis for the resolution of Generic Issue 153: Loss of essential service water in LWRs

    SciTech Connect

    Su, T.M.

    1993-08-01

    In this report, the staff of the US Nuclear Regulatory Commission provides a regulatory analysis for the proposed resolution of Generic Issue 153 (GI-153), ``Loss of Essential Service Water in LWRS.`` GI-153 deals with the concerns pertaining to the reliability of essential service water (ESW) system and related problems for all light water reactors except the seven multi-unit sites addressed by GI-130. ``Essential Service Water Pump failures at Multi-Unit Sites.`` On the basis of the technical findings of a scoping study for GI-153, the staff recommends that the insights gained from the study serve as a complement to the on-going ESW performance inspection program. The staff also concludes that ESW system reliability is being addressed by various on-going regulatory programs. Therefore, the staff recommends that GI-153 should be considered ``RESOLVED.`` The need for future action(s) on ESW reliability is expected to be determined from these on-going programs.

  10. Age and reemployment success after job loss: An integrative model and meta-analysis.

    PubMed

    Wanberg, Connie R; Kanfer, Ruth; Hamann, Darla J; Zhang, Zhen

    2016-04-01

    Despite widespread popular concern about what it means to be over 40 and unemployed, little attention has been paid in the literature to clarifying the role of age within the job seeking experience. Extending theory, we propose mechanisms by which chronological age affects job search and reemployment outcomes after job loss. Through a meta-analysis and examination of 2 supplemental datasets, we examine 5 questions: (a) How strong is the relationship between age and reemployment speed? (b) Does age disadvantage individuals with respect to other reemployment outcomes? (c) Is the relationship between age and reemployment outcomes mediated by job search activities? (d) Are these relationships generalizable? and (e) Are these relationships linear or curvilinear? Our findings provide evidence for a negative relationship between age and reemployment status and speed across job search decade, world region, and unemployment rate, with the strength of the negative relationship becoming stronger over age 50. Job search self-efficacy and job search intensity partially mediate the relationship between age and both reemployment status and speed. (PsycINFO Database Record

  11. Qualitative content analysis of online news media coverage of weight loss surgery and related reader comments.

    PubMed

    Glenn, N M; Champion, C C; Spence, J C

    2012-10-01

    The media has the ability to affect public opinion and policy direction. Prevalence of morbid obesity in Canada is increasing; as is the only effective long-term treatment, weight loss surgery (WLS). Limited research has explored media re/presentations of WLS. The purpose of this study was to examine national online news coverage (and reader comments) of WLS using content analysis. We sought to understand the dominant messages being conveyed within the news texts and reader comments, specifically whose voice was represented, who was the intended audience and what was the overall tone. Articles and comments were retrieved from the Canadian Broadcasting Corporation news web site and analysed using line-by-line techniques. Articles were predominantly 'positive/supportive' (63%) in tone and frequently presented the voices and opinions of 'experts' conveying a biomedical perspective. Comments were overwhelmingly 'negative' (56%) and often derogatory including such language as 'piggy' and 'fatty'. Comments were almost exclusively anonymous (99%) and were frequently directed at other commenters (33%) and 'fat' people (6%). The potentially problematic nature of media framing and reader comments, particularly as they could relate to weight-based stigmatization and discrimination is discussed.

  12. Uplink scheduling and adjacent-channel coupling loss analysis for TD-LTE deployment.

    PubMed

    Yeo, Woon-Young; Moon, Sung Ho; Kim, Jae-Hoon

    2014-01-01

    TD-LTE, one of the two duplexing modes in LTE, operates in unpaired spectrum and has the advantages of TDD-based technologies. It is expected that TD-LTE will be more rapidly deployed in near future and most of WiMax operators will upgrade their networks to TD-LTE gradually. Before completely upgrading to TD-LTE, WiMax may coexist with TD-LTE in an adjacent frequency band. In addition, multiple TD-LTE operators may deploy their networks in adjacent bands. When more than one TDD network operates in adjacent frequency bands, severe interference may happen due to adjacent channel interference (ACI) and unsynchronized operations. In this paper, coexistence issues between TD-LTE and other systems are analyzed and coexistence requirements are provided. This paper has three research objectives. First, frame synchronization between TD-LTE and WiMax is discussed by investigating possible combinations of TD-LTE and WiMax configurations. Second, an uplink scheduling algorithm is proposed to utilize a leakage pattern of ACI in synchronized operations. Third, minimum requirements for coexistence in unsynchronized operations are analyzed by introducing a concept of adjacent-channel coupling loss. From the analysis and simulation results, we can see that coexistence of TD-LTE with other TDD systems is feasible if the two networks are synchronized. For the unsynchronized case, some special cell-site engineering techniques may be required to reduce the ACI.

  13. Kinematic analysis of step ascent among patients with central visual field loss.

    PubMed

    Timmis, Matthew A; Scarfe, Amy C; Tabrett, Daryl R; Pardhan, Shahina

    2014-01-01

    Vision is of paramount importance in regulating adaptive gait. Using three-dimensional motion analysis, the current study investigated how central visual field loss (CFL) affects step ascent. Ten patients with chronic CFL (77 ± 10 years) and 13 visual normal participants (72 ± 6 years) walked up to and ascended a single step (of varying height). Movement kinematics assessed the period immediately prior to and during step ascent. Compared to visual normal participants, patients with CFL exhibited a lower lead foot horizontal crossing velocity, increased lead limb swing time and increased head flexion (looking down at more immediate areas of the ground/step). They also took longer to initiate the step up, transfer weight to the lead foot upon landing on the upper level and increased trail limb swing time when negotiating the medium and high step height. Increased variability was also shown in a number of dependent measures. Data indicate that during step ascent, patients with CFL exhibit a cautious stepping strategy when compared to visual normal participants. This cautious strategy becomes increasingly evident when negotiating higher step heights, as shown by an increased planning time prior to entering the relatively unstable period of single support during the step up. The increased variability among CFL patients increases their likelihood of experiencing dynamic instability and falling during step ascent.

  14. Association of interleukin-10 gene promoter polymorphisms with recurrent pregnancy loss: a meta-analysis.

    PubMed

    Gu, Chongjuan; Gong, Hongxia; Zhang, Zheng; Yang, Zhao; Ma, Yongxin

    2016-07-01

    It has been reported single-nucleotide polymorphisms (SNPs) of the IL-10 promoter might be associated with the susceptibility to recurrent pregnancy loss (RPL). Owing to the inconclusive results, we conducted a meta-analysis to systematically summarize and clarify the association between the IL-10 promoter SNPs and RPL risk. A systematic search of studies on the association of the three SNPs with RPL was conducted in PubMed and Embase. Odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were used to pool the effect size. Eleven case-control studies on rs1800896, seven studies on rs1800871, and eight studies on rs1800872 were included. A significant association was identified between IL-10 rs1800896 with RPL risk (G versus A: OR = 1.21, 95 % CI 1.09-1.35). No evidence of association was found between rs1800871 and RPL when restricted to those studies in Hardy-Weinberg equilibrium in controls (T versus C: OR = 1.25, 95 % CI 0.76-2.06). No statistical association was demonstrated between rs1800872 and RPL (C versus A: OR = 1.08, 95 % CI 0.83-1.42). IL-10 rs1800896 significantly increases the risk of RPL, while rs1800872 is not correlated with RPL risk. No significant association is demonstrated between rs1800871 and RPL risk but this requires further investigation.

  15. Histomorphometrical analysis of the effects of the bisphosphonate alendronate on bone loss caused by experimental periodontitis in monkeys.

    PubMed

    Weinreb, M; Quartuccio, H; Seedor, J G; Aufdemorte, T B; Brunsvold, M; Chaves, E; Kornman, K S; Rodan, G A

    1994-01-01

    This study tested the efficacy of alendronate, a bisphosphate, in reducing alveolar bone loss caused by experimental periodontitis in cynomolgus monkeys. Periodontitis was initiated in adult monkeys by ligating mandibular molar teeth at the cementoenamel junction (CEJ) and subsequently inoculating the ligature with Porphyromonas (Bacteroides) gingivalis. Contralateral, homologous non-ligated teeth served as controls. Animals received, intravenously, either saline (placebo) or alendronate at 0.05 or 0.25 mg/kg every 2 weeks for 16 weeks. After the animals were sacrificed, coronal sections through mandibular molars were subjected to histomorphometrical analysis. No overt side-effects were observed in any of the animals participating in this study. In placebo-treated animals, ligation and inoculation resulted in significant bone loss both at the CEJ and at the furcation. Alendronate at 0.05 mg/kg significantly reduced bone loss associated with the experimental periodontitis at both sites. In contrast, the dose of 0.25 mg/kg was ineffective in attenuating alveolar bone loss in the furcation area and only slightly effective in preventing it at the CEJ area. The results of the histomorphometric analysis correlate closely with those of the radiographic analysis of the same experiment. These data indicate that alendronate could reduce the loss of alveolar support associated with periodontitis and suggest that bisphosphonates, by virtue of their significant inhibitory action on osteoclasts, may become a treatment modality in the battle against alveolar bone destruction during periodontal disease.

  16. Intratympanic steroids as a salvage treatment for sudden sensorineural hearing loss? A meta-analysis.

    PubMed

    Ng, Jia Hui; Ho, Roger Chun Man; Cheong, Crystal Shuk Jin; Ng, Adele; Yuen, Heng Wai; Ngo, Raymond Yeow Seng

    2015-10-01

    Sudden sensorineural hearing loss is typically treated with systemic steroids. The aim of this meta-analysis was to evaluate the efficacy of salvage intratympanic steroid treatment in patients who have initial treatment failure with systemic steroids. A MEDLINE literature search was performed, supported by searches of Web of Science, Biosis, and Science Direct. Articles of all languages were included. Selection of relevant publications was conducted independently by three authors. Only randomized controlled trials were considered. In one arm of the studies, the patients received salvage intratympanic steroids. In the other arm, patients did not receive further treatment. The standard difference in mean (SDM) amount of improvement in hearing threshold between patients who did and did not receive salvage intratympanic steroids was calculated. From an initial 184 studies found via the search strategy, 5 studies met inclusion criteria and were included. There was a statistically significant greater reduction in hearing threshold on pure-tone audiometry in patients who received salvage intratympanic steroids than in those who did not (SDM = -0.401, p = 0.005). Subgroup analysis showed that administration by intratympanic injection (SDM = -0.375, p = 0.013) rather than a round window catheter (SDM = -0.629, p = 0.160) yielded significant improvement in outcome. The usage of dexamethasone yielded better outcomes (SDM = -0.379, p = 0.039) than the use of methylprednisolone (SDM = -0.459, p = 0.187). No serious side effect of treatment was reported. In patients who have failed initial treatment with systemic steroids, additional treatment with salvage intratympanic dexamethasone injections demonstrate a statistically significant reduction in the hearing thresholds as compared to controls.

  17. The effects of green tea on weight loss and weight maintenance: a meta-analysis.

    PubMed

    Hursel, R; Viechtbauer, W; Westerterp-Plantenga, M S

    2009-09-01

    Different outcomes of the effect of green tea on weight loss (WL) and weight maintenance (WM) have been reported in studies with subjects differing in ethnicity and habitual caffeine intake. To elucidate by meta-analysis whether green tea indeed has a function in body weight regulation. English-language studies about WL and WM after green tea supplementation were identified through PubMed and based on the references from retrieved articles. Out of the 49 studies initially identified, a total of 11 articles fitted the inclusion criteria and provided useful information for the meta-analysis. Effect sizes (mean weight change in treatment versus control group) were computed and aggregated based on a random-effects model. The influence of several moderators on the effect sizes was examined. Catechins significantly decreased body weight and significantly maintained body weight after a period of WL (microcirc=-1.31 kg; P<0.001). Inhibition of this effect by high habitual caffeine intake (>300 mg per day) failed to reach significance (microcirc=-0.27 kg for high and microcirc=-1.60 kg for low habitual caffeine intake; P=0.09). Also, the seemingly smaller effect of catechins in Caucasian (microcirc=-0.82 kg) subjects compared with Asians (microcirc=-1.51 kg; P=0.37) did not reach significance. Interaction of ethnicity and caffeine intake was a significant moderator (P=0.04). Catechins or an epigallocatechin gallate (EGCG)-caffeine mixture have a small positive effect on WL and WM. The results suggest that habitual caffeine intake and ethnicity may be moderators, as they may influence the effect of catechins.

  18. Intratympanic dexamethasone in sudden sensorineural hearing loss: A systematic review and meta-analysis.

    PubMed

    El Sabbagh, Nagi G; Sewitch, Maida J; Bezdjian, Aren; Daniel, Sam J

    2017-08-01

    Systemic dexamethasone has demonstrated conclusive benefits in reversing sudden sensorineural hearing loss (SSNHL) despite considerable number of potential side effects. In contrast, the intratympanic route of steroid administration averts several possible complications. This study aims to examine the literature to delineate the efficacy and side effect of intratympanic dexamethasone (ITD) injection for the treatment of SSNHL. Cochrane, Embase, and MEDLINE electronic databases from January 1950 to August 2014, with an update performed on November 10, 2014. Systematic review and meta-analysis of randomized controlled clinical trials (RCCTs), using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow diagram and guidelines. Quality assessment was performed using The Cochrane Collaboration Tool for Assessing Risk of Bias. Eight RCCTs on SSNHL were included Three of the eight studies had high risk of bias. Substantial heterogeneity was found. The meta-analysis failed to detect statistically significant difference between ITD and alternative treatment (odds ratio = 0.39, 95% credible intervals = 0.11-1.27). The side-effects profile was favorable for ITD. No serious adverse events were recorded. There is no sufficient scientific evidence to support a difference between ITD and alternative therapy for SSNHL. We recommend larger RCCTs to determine the effectiveness of ITD compared to oral steroid therapy. We encourage a shift in study design selection toward noninferiority or superiority studies. Avoiding systemic corticotherapy, especially in vulnerable populations, should be the rationale for future research in the field. Laryngoscope, 127:1897-1908, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  19. Preliminary Analysis of Aircraft Loss of Control Accidents: Worst Case Precursor Combinations and Temporal Sequencing

    NASA Technical Reports Server (NTRS)

    Belcastro, Christine M.; Groff, Loren; Newman, Richard L.; Foster, John V.; Crider, Dennis H.; Klyde, David H.; Huston, A. McCall

    2014-01-01

    Aircraft loss of control (LOC) is a leading cause of fatal accidents across all transport airplane and operational classes, and can result from a wide spectrum of hazards, often occurring in combination. Technologies developed for LOC prevention and recovery must therefore be effective under a wide variety of conditions and uncertainties, including multiple hazards, and their validation must provide a means of assessing system effectiveness and coverage of these hazards. This requires the definition of a comprehensive set of LOC test scenarios based on accident and incident data as well as future risks. This paper defines a comprehensive set of accidents and incidents over a recent 15 year period, and presents preliminary analysis results to identify worst-case combinations of causal and contributing factors (i.e., accident precursors) and how they sequence in time. Such analyses can provide insight in developing effective solutions for LOC, and form the basis for developing test scenarios that can be used in evaluating them. Preliminary findings based on the results of this paper indicate that system failures or malfunctions, crew actions or inactions, vehicle impairment conditions, and vehicle upsets contributed the most to accidents and fatalities, followed by inclement weather or atmospheric disturbances and poor visibility. Follow-on research will include finalizing the analysis through a team consensus process, defining future risks, and developing a comprehensive set of test scenarios with correlation to the accidents, incidents, and future risks. Since enhanced engineering simulations are required for batch and piloted evaluations under realistic LOC precursor conditions, these test scenarios can also serve as a high-level requirement for defining the engineering simulation enhancements needed for generating them.

  20. Analysis of Effects of Inlet Pressure Losses on Performance of Axial-Flow Type Turbojet Engine

    NASA Technical Reports Server (NTRS)

    Sanders, Newell D; Palasics, John

    1948-01-01

    The experimentally determined performance characteristics of an axial-flow turbojet engine have been used to estimate the effects of inlet total-pressure losses on net thrust and specific fuel consumption at a constant engine speed. At low altitudes and flight Mach numbers, inlet pressure losses cause an increase in engine discharge temperature and it is possible that the maximum allowable turbine temperature maybe exceeded. An inlet absolute total-pressure loss of 10 percent will result in a thrust loss of 14 percent and a 15-percent increase in specific fuel consumption based on net thrust. At high altitudes and flight Mach numbers, choking conditions exist in the exhaust nozzle and the inlet pressure losses do not affect the discharge temperatures. Under these conditions, a 10-percent loss in inlet absolute total pressure produces a 22-percent loss in net thrust and a 16-percent increase in specific fuel consumption. If the exhaust-nozzle-outlet area is adjusted to compensate for the effect of inlet losses on discharge temperature in the nonchoking cases (low altitude and Mach numbers), the thrust and fuel consumption will be changed in a manner similar to the results obtained in the choking cases.

  1. Parameter uncertainty analysis for the annual phosphorus loss estimator (APLE) model

    USDA-ARS?s Scientific Manuscript database

    Technical abstract: Models are often used to predict phosphorus (P) loss from agricultural fields. While it is commonly recognized that model predictions are inherently uncertain, few studies have addressed prediction uncertainties using P loss models. In this study, we conduct an uncertainty analys...

  2. Incorporating Mythic and Interpretive Analysis in the Investigation of Hearing Loss on the Family Farm

    ERIC Educational Resources Information Center

    Meister, Mark; Hest, Theresa; Burnett, Ann

    2010-01-01

    Despite knowing about the dangers of hearing loss, farmers typically choose not to protect their hearing. Examining the myth of farm life, this study aims to discern whether rhetorical myths influence farmers' decisions to wear hearing protection. Researchers conducted 40 interviews with farmers regarding farm life and hearing loss. Results…

  3. Multiple trajectory analysis of MLS observed stratospheric chemical ozone loss in Arctic winter 1995/96

    NASA Astrophysics Data System (ADS)

    Lemmen, C.; Riese, R.; Grooss, J.-U.; Mueller, R.

    2003-04-01

    Daily ozone loss rates and total chemical ozone depletion during Arctic winter 1995/96 were evaluated based on ozone measurements by the Microwave Limb Sounder (MLS) instrument onboard the Upper Atmosphere Research Satellite (UARS). Employing the 3-dimensional transport scheme of the Chemical Lagrangian Model of the Stratosphere (CLaMS), trajectories from successive satellite measurements were compared with each other using a variation of the Match technique, such that ozone concentration differences between double sounded (``matched'') air parcels represent chemical ozone loss. The ensemble average of many (typically 30--150) matches yields an average ozone depletion rate for the area covered by the trajectories. Total ozone loss from late December to early March was 1.4 ppmv at the 475 K isentropic level within the vortex core (PV > 45 PVU at 475 K). Ozone loss decreased towards the edge of the vortex, no significant ozone loss could be observed in the outer vortex edge (between ≈ 27 and ≈ 35 PVU). Daily ozone loss was found to average 10 ppbv/day throughout January and throughout the extended vortex area. For the month of February daily ozone loss rates were highly variable and peaked at 40 ppbv/day in the vortex (≈ 35 PVU). In this study, no chemical ozone loss could be observed in the outer vortex edge region during February, which suggests that the dynamically defined vortex boundary separated two different chemical regimes during February, but not in January.

  4. Inhibition of Kv channel expression by NSAIDs depolarizes membrane potential and inhibits cell migration by disrupting calpain signaling

    PubMed Central

    Silver, Kristopher; Littlejohn, Alaina; Thomas, Laurel; Marsh, Elizabeth; Lillich, James D.

    2015-01-01

    Clinical use of non-steroidal anti-inflammatory drugs (NSAIDs) is well known to cause gastrointestinal ulcer formation via several mechanisms that include inhibiting epithelial cell migration and mucosal restitution. The drug-affected signaling pathways that contribute to inhibition of migration by NSAIDs are poorly understood, though previous studies have shown that NSAIDs depolarize membrane potential and suppress expression of calpain proteases and voltage-gated potassium (Kv) channel subunits. Kv channels play significant roles in cell migration and are targets of NSAID activity in white blood cells, but the specific functional effects of NSAID-induced changes in Kv channel expression, particularly on cell migration, are unknown in intestinal epithelial cells. Accordingly, we investigated the effects of NSAIDs on expression of Kv1.3, 1.4, and 1.6 in vitro and/or in vivo and evaluated the functional significance of loss of Kv subunit expression. Indomethacin or NS-398 reduced total and plasma membrane protein expression of Kv1.3 in cultured intestinal epithelial cells (IEC-6). Additionally, depolarization of membrane potential with margatoxin (MgTx), 40 mM K+, or silencing of Kv channel expression with siRNA significantly reduced IEC-6 cell migration and disrupted calpain activity. Furthermore, in rat small intestinal epithelia, indomethacin and NS-398 had significant, yet distinct, effects on gene and protein expression of Kv1.3, 1.4, or 1.6, suggesting that these may be clinically relevant targets. Our results show that inhibition of epithelial cell migration by NSAIDs is associated with decreased expression of Kv channel subunits, and provide a mechanism through which NSAIDs inhibit cell migration and may contribute to NSAID-induced gastrointestinal (GI) toxicity. PMID:26549367

  5. Inhibition of Kv channel expression by NSAIDs depolarizes membrane potential and inhibits cell migration by disrupting calpain signaling.

    PubMed

    Silver, Kristopher; Littlejohn, Alaina; Thomas, Laurel; Marsh, Elizabeth; Lillich, James D

    2015-12-15

    Clinical use of non-steroidal anti-inflammatory drugs (NSAIDs) is well known to cause gastrointestinal ulcer formation via several mechanisms that include inhibiting epithelial cell migration and mucosal restitution. The drug-affected signaling pathways that contribute to inhibition of migration by NSAIDs are poorly understood, though previous studies have shown that NSAIDs depolarize membrane potential and suppress expression of calpain proteases and voltage-gated potassium (Kv) channel subunits. Kv channels play significant roles in cell migration and are targets of NSAID activity in white blood cells, but the specific functional effects of NSAID-induced changes in Kv channel expression, particularly on cell migration, are unknown in intestinal epithelial cells. Accordingly, we investigated the effects of NSAIDs on expression of Kv1.3, 1.4, and 1.6 in vitro and/or in vivo and evaluated the functional significance of loss of Kv subunit expression. Indomethacin or NS-398 reduced total and plasma membrane protein expression of Kv1.3 in cultured intestinal epithelial cells (IEC-6). Additionally, depolarization of membrane potential with margatoxin (MgTx), 40mM K(+), or silencing of Kv channel expression with siRNA significantly reduced IEC-6 cell migration and disrupted calpain activity. Furthermore, in rat small intestinal epithelia, indomethacin and NS-398 had significant, yet distinct, effects on gene and protein expression of Kv1.3, 1.4, or 1.6, suggesting that these may be clinically relevant targets. Our results show that inhibition of epithelial cell migration by NSAIDs is associated with decreased expression of Kv channel subunits, and provide a mechanism through which NSAIDs inhibit cell migration and may contribute to NSAID-induced gastrointestinal (GI) toxicity.

  6. Extended frequency analysis of magnetic losses under rotating induction in soft magnetic composites

    NASA Astrophysics Data System (ADS)

    de la Barrière, O.; Appino, C.; Fiorillo, F.; Ragusa, C.; Lecrivain, M.; Rocchino, L.; Ben Ahmed, H.; Gabsi, M.; Mazaleyrat, F.; LoBue, M.

    2012-04-01

    We present novel results on magnetic losses in soft magnetic composites (SMCs) excited with rotating field. Soft composites are very promising in electrical engineering applications, where new topologies of electrical machines with two- and three-dimensional induction loci are increasingly found. An experimental characterization of industrial SMC products has, therefore, been carried out, up to the kilohertz range, under alternating and circular flux loci, making use of a specifically designed and optimized loss measuring setup. The obtained results have been analyzed for all kinds of excitation, according to the loss separation concept, with the emphasis being placed on the relationship between the rotational and the alternating loss components. In particular, it is found that the ratio between the rotational and the alternating losses is, for any given peak induction, independent of frequency.

  7. Direct depolarization and antidromic action potentials transiently suppress dendritic IPSPs in hippocampal CA1 pyramidal cells.

    PubMed

    Morishita, W; Alger, B E

    2001-01-01

    Whole-cell current-clamp recordings were made from distal dendrites of rat hippocampal CA1 pyramidal cells. Following depolarization of the dendritic membrane by direct injection of current pulses or by back-propagating action potentials elicited by antidromic stimulation, evoked gamma-aminobutyric acid-A (GABA(A)) receptor-mediated inhibitory postsynaptic potentials (IPSPs) were transiently suppressed. This suppression had properties similar to depolarization-induced suppression of inhibition (DSI): it was enhanced by carbachol, blocked by dendritic hyperpolarization sufficient to prevent action potential invasion, and reduced by 4-aminopyridine (4-AP) application. Thus DSI or a DSI-like process can be recorded in CA1 distal dendrites. Moreover, localized application of TTX to stratum pyramidale blocked somatic action potentials and somatic IPSPs, but not dendritic IPSPs or DSI induced by direct dendritic depolarization, suggesting DSI is expressed in part in the dendrites. These data extend the potential physiological roles of DSI.

  8. GABA depolarizes immature neurons and inhibits network activity in the neonatal neocortex in vivo.

    PubMed

    Kirmse, Knut; Kummer, Michael; Kovalchuk, Yury; Witte, Otto W; Garaschuk, Olga; Holthoff, Knut

    2015-07-16

    A large body of evidence from in vitro studies suggests that GABA is depolarizing during early postnatal development. However, the mode of GABA action in the intact developing brain is unknown. Here we examine the in vivo effects of GABA in cells of the upper cortical plate using a combination of electrophysiological and Ca(2+)-imaging techniques. We report that at postnatal days (P) 3-4, GABA depolarizes the majority of immature neurons in the occipital cortex of anaesthetized mice. At the same time, GABA does not efficiently activate voltage-gated Ca(2+) channels and fails to induce action potential firing. Blocking GABA(A) receptors disinhibits spontaneous network activity, whereas allosteric activation of GABA(A) receptors has the opposite effect. In summary, our data provide evidence that in vivo GABA acts as a depolarizing neurotransmitter imposing an inhibitory control on network activity in the neonatal (P3-4) neocortex.

  9. Retrievals of Aerosol and Cloud Particle Microphysics Using Polarization and Depolarization Techniques

    NASA Technical Reports Server (NTRS)

    Mishchenko, Michael; Hansen, James E. (Technical Monitor)

    2001-01-01

    The recent availability of theoretical techniques for computing single and multiple scattering of light by realistic polydispersions of spherical and nonspherical particles and the strong dependence of the Stokes scattering matrix on particle size, shape, and refractive index make polarization and depolarization measurements a powerful particle characterization tool. In this presentation I will describe recent applications of photopolarimetric and lidar depolarization measurements to remote sensing characterization of tropospheric aerosols, polar stratospheric clouds (PSCs), and contrails. The talk will include (1) a short theoretical overview of the effects of particle microphysics on particle single-scattering characteristics; (2) the use of multi-angle multi-spectral photopolarimetry to retrieve the optical thickness, size distribution, refractive index, and number concentration of tropospheric aerosols over the ocean surface; and (3) the application of the T-matrix method to constraining the PSC and contrail particle microphysics using multi-spectral measurements of lidar backscatter and depolarization.

  10. Relation between circular and linear depolarization ratios under multiple-scattering conditions.

    PubMed

    Roy, Gilles; Roy, Nathalie

    2008-12-10

    A simple relationship is established between the linear and the circular depolarization ratios averaged over the azimuth angle of clouds made of spherical particles. The relationship is validated theoretically using double-scattering calculations; in the framework, the measurements are performed with a multiple-field-of-view lidar (MFOV) lidar. The relationship is also validated using data obtained with MFOV lidar equipped with linear and circular polarization measurement capabilities. The experimental data support theoretical results for small optical depths. At higher optical depths and large fields of view, the contribution of multiple scatterings is important; experimental data suggest that the relationship established between the linear and circular depolarization stays valid as long as the main depolarization mechanism comes from one scattering (most likely a backscattering a few degrees away from 180 degrees ).

  11. Stability theorem of depolarizing channels for the minimal output quantum Rényi entropies

    NASA Astrophysics Data System (ADS)

    Bae, Eunok; Gour, Gilad; Lee, Soojoon; Park, Jeonghoon; Sanders, Barry C.

    2016-03-01

    The stability theorem of the depolarizing channel states that if a state is close to achieving the minimal/maximal output value of a certain quantity through the channel, then it must be close to an input state giving the minimal/maximal value. We show that the stability theorem of the depolarizing channel holds for the output quantum p-Rényi entropy for p≥slant 2 or p = 1, which is an extension of the known case p = 2. As an application, we present a protocol in which Bob determines whether Alice prepares a pure quantum state close to a product state. In the protocol, Alice transmits to Bob multiple copies of a pure state through a depolarizing channel, and Bob estimates its output quantum p-Rényi entropy. By using our stability theorem, we show that Bob can determine whether her preparation is appropriate.

  12. Retrievals of Aerosol and Cloud Particle Microphysics Using Polarization and Depolarization Techniques

    NASA Technical Reports Server (NTRS)

    Mishchenko, Michael; Hansen, James E. (Technical Monitor)

    2001-01-01

    The recent availability of theoretical techniques for computing single and multiple scattering of light by realistic polydispersions of spherical and nonspherical particles and the strong dependence of the Stokes scattering matrix on particle size, shape, and refractive index make polarization and depolarization measurements a powerful particle characterization tool. In this presentation I will describe recent applications of photopolarimetric and lidar depolarization measurements to remote sensing characterization of tropospheric aerosols, polar stratospheric clouds (PSCs), and contrails. The talk will include (1) a short theoretical overview of the effects of particle microphysics on particle single-scattering characteristics; (2) the use of multi-angle multi-spectral photopolarimetry to retrieve the optical thickness, size distribution, refractive index, and number concentration of tropospheric aerosols over the ocean surface; and (3) the application of the T-matrix method to constraining the PSC and contrail particle microphysics using multi-spectral measurements of lidar backscatter and depolarization.