Science.gov

Sample records for depolarization loss analysis

  1. Malaria: the value of the automated depolarization analysis.

    PubMed

    Josephine, F P; Nissapatorn, V

    2005-01-01

    This retrospective and descriptive study was carried out in the University of Malaya Medical Center (UMMC) from January to September, 2004. This study aimed to evaluate the diagnostic utility of the Cell-Dyn 4000 hematology analyzer's depolarization analysis and to determine the sensitivity and specificity of this technique in the context of malaria diagnosis. A total of 889 cases presenting with pyrexia of unknown origin or clinically suspected of malaria were examined. Sixteen of these blood samples were found to be positive; 12 for P. vivax, 3 for P. malariae, and 1 for P. falciparum by peripheral blood smear as the standard technique for parasite detection and species identification. Demographic characteristics showed that the majority of patients were in the age range of 20-57 with a mean of 35.9 (+/- SD) 11.4 years, and male foreign workers. Of these, 16 positive blood samples were also processed by Cell-Dyne 4000 analyzer in the normal complete blood count (CBC) operational mode. Malaria parasites produce hemozoin, which depolarizes light and this allows the automated detection of malaria during routine complete blood count analysis with the Abbot Cell-Dyn CD4000 instrument. The white blood cell (WBC) differential plots of all malaria positive samples showed abnormal depolarization events in the NEU-EOS and EOS I plots. This was not seen in the negative samples. In 12 patients with P. vivax infection, a cluster pattern in the Neu-EOS and EOS I plots was observed, and appeared color-coded green or black. In 3 patients with P. malariae infection, few random depolarization events in the NEU-EOS and EOS I plots were seen, and appeared color-coded green, black or blue. While in the patient with P. falciparum infection, the sample was color-coded green with a few random purple depolarizing events in the NEU-EOS and EOS I plots. This study confirms that automated depolarization analysis is a highly sensitive and specific method to diagnose whether or not a patient

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

    NASA Astrophysics Data System (ADS)

    Mousavi, Seyedeh Laleh; Sabaeian, Mohammad

    2016-07-01

    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.

  3. Measurement of the Loss and Depolarization Probability of UCN on Beryllium and Diamond Like Carbon Films

    PubMed Central

    Brys, Tomas; Daum, Manfred; Fierlinger, Peter; Geltenbort, Peter; Gupta, Mukul; Henneck, Reinhold; Heule, Stefan; Kirch, Klaus; Lasakov, Mikhail; Mammei, Russel; Makela, Mark; Pichlmaier, Axel; Serebrov, Anatoli; Straumann, Ulrich; Vogelaar, Robert B.; Wermelinger, Cedric; Young, Albert

    2005-01-01

    Currently several institutes worldwide are working on the development of a new generation of ultracold neutron (UCN) sources. In parallel with source development, new materials for guiding and storage of UCN are developed. Currently the best results have been achieved using 58Ni, Be, solid O2 and low temperature Fomblin oil (LTF). All of these materials have their shortcomings like cost, toxicity or difficulty of use. A novel very promising material is diamond like carbon (DLC). Several techniques exist to coat surfaces, and industrial applications (e.g., for extremely hard surfaces) are already wide spread. Preliminary investigations using neutron reflectometry at PSI and Los Alamos yielded a critical velocity for DLC of about 7 m/s thus comparable to Beryllium. A low upper limit of depolarization probability for stored polarized UCN has been measured at the PF2 facility of the Institut Laue-Langevin (ILL) by North Carolina State University (NCSU), Los Alamos National Laboratory (LANL), and Petersburg Nuclear Physics Institute (PNPI), thus making it also a good material for storage and guidance of polarized UCN. Still missing is the loss probability per bounce. We will be able to extract this number and a more stringent value for the depolarization from our experiment thus proving the suitability of DLC as a wall material for a wide range of UCN applications. PMID:27308136

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. Whole-Exome Sequencing and Homozygosity Analysis Implicate Depolarization-Regulated Neuronal Genes in Autism

    PubMed Central

    Chahrour, Maria H.; Yu, Timothy W.; Lim, Elaine T.; Ataman, Bulent; Coulter, Michael E.; Hill, R. Sean; Stevens, Christine R.; Schubert, Christian R.; Greenberg, Michael E.; Gabriel, Stacey B.; Walsh, Christopher A.

    2012-01-01

    Although autism has a clear genetic component, the high genetic heterogeneity of the disorder has been a challenge for the identification of causative genes. We used homozygosity analysis to identify probands from nonconsanguineous families that showed evidence of distant shared ancestry, suggesting potentially recessive mutations. Whole-exome sequencing of 16 probands revealed validated homozygous, potentially pathogenic recessive mutations that segregated perfectly with disease in 4/16 families. The candidate genes (UBE3B, CLTCL1, NCKAP5L, ZNF18) encode proteins involved in proteolysis, GTPase-mediated signaling, cytoskeletal organization, and other pathways. Furthermore, neuronal depolarization regulated the transcription of these genes, suggesting potential activity-dependent roles in neurons. We present a multidimensional strategy for filtering whole-exome sequence data to find candidate recessive mutations in autism, which may have broader applicability to other complex, heterogeneous disorders. PMID:22511880

  9. 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).

  10. 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).

  11. 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. PMID:27281718

  12. 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

  13. Spin freezing process in a reentrant ferromagnet studied by neutron depolarization analysis

    SciTech Connect

    Sato, T.; Shinohara, T.; Ogawa, T.; Takeda, M.

    2004-10-01

    The spin freezing process and the magnetic nature of reentrant spin-glass (RSG) and the ferromagnetic (FM) phases of a typical reentrant ferromagnet Ni{sub 78}Mn{sub 22} were investigated based on neutron depolarization analysis, and the results were compared with the previous Moessbauer measurements [Phys. Rev. B 64, 184432 (2001)]. The wavelength-dependent polarization, under a field cooled (FC) condition, showed the damped oscillatory behavior in both the RSG and FM phases, except in the temperature region just above the RSG temperature T{sub RSG}{approx}60 K. At a temperature of around 80 K, however, it showed a double oscillatory behavior. The field integral I, which is proportional to the mean local magnetic induction, was deduced as a function of the temperature. Two branches of temperature-dependent field integrals were found: a low-temperature I{sub low}-branch, which has a small value of I, stopped at a temperature below the Curie temperature T{sub C}{approx}160 K, and a high temperature I{sub high}-branch, which has a large value of I, appeared just below 80 K. This means that there are two kinds of magnetic environments, and they have different values of magnetization. This is consistent with the observation of the double peak spectrum of the hyperfine field in the previous Moessbauer measurements. The present neutron data and the Moessbauer data can be interpreted along a scenario of reentrant behavior, which consists of the low-temperature spin canting state and the ''melting of frustrated spins'' mechanism introduced by Saslow and Parker [Phys. Rev. Lett. 56, 1074 (1986)], except for the absence of the observation of singularity in the temperature-dependent magnetization. Based on such considerations, we constructed a comprehensive picture of the spin freezing process and the magnetic nature of the RSG and FM phases in the reentrant ferromagnet.

  14. Ultracold neutron depolarization in magnetic bottles

    NASA Astrophysics Data System (ADS)

    Steyerl, A.; Kaufman, C.; Müller, G.; Malik, S. S.; Desai, A. M.

    2012-12-01

    We analyze the depolarization of ultracold neutrons confined in a magnetic field configuration similar to those used in existing or proposed magnetogravitational storage experiments aiming at a precise measurement of the neutron lifetime. We use an extension of the semiclassical Majorana approach as well as an approximate quantum mechanical analysis, both pioneered by Walstrom [Nucl. Instrum. Methods Phys. Res. A10.1016/j.nima.2008.11.010 599, 82 (2009)]. In contrast with this previous work we do not restrict the analysis to purely vertical modes of neutron motion. The lateral motion is shown to cause the predominant depolarization loss in a magnetic storage trap. The system studied also allowed us to estimate the depolarization loss suffered by ultracold neutrons totally reflected on a nonmagnetic mirror immersed in a magnetic field. This problem is of preeminent importance in polarized neutron decay studies such as the measurement of the asymmetry parameter A using ultracold neutrons, and it may limit the efficiency of ultracold neutron polarizers based on passage through a high magnetic field.

  15. 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

  16. Analysis of optimum conditions of depolarization imaging by polarization-sensitive optical coherence tomography in the human retina

    NASA Astrophysics Data System (ADS)

    Sugita, Mitsuro; Pircher, Michael; Zotter, Stefan; Baumann, Bernhard; Saito, Kenichi; Makihira, Tomoyuki; Tomatsu, Nobuhiro; Sato, Makoto; Hitzenberger, Christoph K.

    2015-01-01

    Measurement and imaging of depolarization by polarization-sensitive optical coherence tomography (PS-OCT) requires averaging of Stokes vector elements within two- or three-dimensional (3-D) evaluation windows to obtain the degree of polarization uniformity (DOPU). By use of a PS-OCT system with an integrated retinal tracker, we analyze optimum conditions for depolarization imaging, data processing, and segmentation of depolarizing tissue in the human retina. The trade-offs between figures of merit like DOPU imaging sensitivity, efficiency, and susceptibility are evaluated in terms of 3-D resolution. The results are used for a new, detailed interpretation of PS-OCT high-resolution images of the human retinal pigment epithelium and Bruch's membrane.

  17. Analysis of the depolarizing properties of normal and adenomatous polyps in colon mucosa for the early diagnosis of precancerous lesions

    NASA Astrophysics Data System (ADS)

    Ortega-Quijano, Noé; Fanjul-Vélez, Félix; de Cos-Pérez, Jesús; Arce-Diego, José Luis

    2011-09-01

    Optical characterization of biological tissues by means of polarimetric techniques is an area of growing interest. Polarized light can be used for malignant neoplasms detection. To our knowledge, few studies have so far focused on lesions that are prone to result in cancer. In this work we present a polarimetric study of depolarization in prepathological tissues. Specifically, we will focus on premalignant lesions in human colon due to their clinical relevance. Colonic adenoma, the potential precursor of malignant adenocarcinoma, provokes significant structural modifications in colon mucosa that affect light depolarization. The depolarizing properties of normal and adenomatous polyps mucosa are compared. The average linear degree of polarization is shown to present a strong dependence with the precancerous state of the colonic tissue. This method has the potential to enable an early diagnosis of colon cancer.

  18. Ischemia-induced spreading depolarization in the retina.

    PubMed

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

    2016-09-01

    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

  19. Differential Modulation of GABAA Receptors Underlies Postsynaptic Depolarization- and Purinoceptor-Mediated Enhancement of Cerebellar Inhibitory Transmission: A Non-Stationary Fluctuation Analysis Study.

    PubMed

    Ono, Yumie; Saitow, Fumihito; Konishi, Shiro

    2016-01-01

    Cerebellar GABAergic inhibitory transmission between interneurons and Purkinje cells (PCs) undergoes a long-lasting enhancement following different stimulations, such as brief depolarization or activation of purinergic receptors of postsynaptic PCs. The underlying mechanisms, however, are not completely understood. Using a peak-scaled non-stationary fluctuation analysis, we therefore aimed at characterizing changes in the electrophysiological properties of GABAA receptors in PCs of rat cerebellar cortex during depolarization-induced "rebound potentiation (RP)" and purinoceptor-mediated long-term potentiation (PM-LTP), because both RP and PM-LTP likely depend on postsynaptic mechanisms. Stimulation-evoked inhibitory postsynaptic currents (eIPSCs) were recorded from PCs in neonatal rat cerebellar slices. Our analysis showed that postsynaptic membrane depolarization induced RP of eIPSCs in association with significant increase in the number of synaptic GABAA receptors without changing the channel conductance. By contrast, bath application of ATP induced PM-LTP of eIPSCs with a significant increase of the channel conductance of GABAA receptors without affecting the receptor number. Pretreatment with protein kinase A (PKA) inhibitors, H-89 and cAMPS-Rp, completely abolished the PM-LTP. The CaMKII inhibitor KN-62 reported to abolish RP did not alter PM-LTP. These results suggest that the signaling mechanism underlying PM-LTP could involve ATP-induced phosphorylation of synaptic GABAA receptors, thereby resulting in upregulation of the channel conductance by stimulating adenylyl cyclase-PKA signaling cascade, possibly via activation of P2Y11 purinoceptor. Thus, our findings reveal that postsynaptic GABAA receptors at the interneuron-PC inhibitory synapses are under the control of two distinct forms of long-term potentiation linked with different second messenger cascades. PMID:26930485

  20. 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.

  1. 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.

  2. Extending Stochastic Network Calculus to Loss Analysis

    PubMed Central

    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. PMID:24228019

  3. Transmission and distribution-loss analysis

    SciTech Connect

    Not Available

    1982-05-01

    A previous study developed a methodology for determining the losses in the various elements of an electric utility transmission and distribution system using only generally published system data. In that study the losses at the system peak and the average annual losses of the Niagara Mohawk Power Corporation system were calculated to illustrate the methods. Since there was little or no system loss data available at that time, the methodology of the loss calculations was not verified. The purpose of this study was to verify the methods that were proposed in the previous study. The data, estimates, assumptions, and calculation methods of the original study were checked against the actual Niagara Mohawk system data. The losses calculated in the original study were compared to the system losses derived from actual system data. Revisions to the original methods were recommended to improve the accuracy of the results. As a result of the analysis done in this study, the methods developed in the original study were revised. The revised methods provide reasonable loss calculation results for the Niagara Mohawk system. These methods along with discussions of their application are given. Also included is a description of the procedures followed to find the system losses from the actual system data. The revised loss calculation methods using the published data based on the Niagara Mohawk system data, operation, and loadings, gave reasonable results for that system, and the method may be applicable to similar systems.

  4. 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.

  5. 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.

  6. An asymptotic analysis of mixing loss

    SciTech Connect

    Fritsch, G.; Giles, M.B.

    1995-07-01

    The objective of this paper is to establish, in a rigorous mathematical manner, a link between the dissipation of unsteadiness in a two-dimensional compressible flow and the resulting mixing loss. A novel asymptotic approach and a control-volume argument are central to the analysis. It represents the first work clearly identifying the separate contributions to the mixing loss from simultaneous linear disturbances, i.e., from unsteady entropy, vorticity, and pressure waves. The results of the analysis have important implications for numerical simulations of turbomachinery flows; the mixing loss at the stator/rotor interface in steady simulations and numerical smoothing are discussed in depth. For a transonic turbine, the entropy rise through the stage is compared for a steady and an unsteady viscous simulation. The large interface mixing loss in the steady simulation is pointed out and its physical significance is discussed. The asymptotic approach is then applied to the first detailed analysis of interface mixing loss. Contributions from different wave types and wavelengths are quantified and discussed.

  7. Inelastic spin depolarization spectroscopy in silicon

    NASA Astrophysics Data System (ADS)

    Li, Jing; Appelbaum, Ian

    2013-07-01

    In ballistic injection spin transport devices, a tunnel junction emitter bias voltage determines the energy at which spin-polarized hot electrons cross a Schottky barrier into the conduction band of a semiconductor collector. Fast energy relaxation via phonon emission restores equilibrium for subsequent transport at the band edge. Through an analysis incorporating voltage-dependent measurement of magnetocurrent polarization in silicon spin transport devices along with magnetic-tunnel- and spin-valve-transistor configurations, the contribution to total spin depolarization caused by this inelastic scattering in the presence of spin-orbit interaction is quantified. From the shape of this spectroscopy, it is found that all measured spin depolarization can be accounted for solely by considering spin relaxation during bulk transport in quasi-equilibrium near the conduction band edge; the relaxation of initial spin state is irrelevant to the spin-dependent device characteristics.

  8. Verification of Loss Reduction based on New Loss Analysis for Slotless PM Motor

    NASA Astrophysics Data System (ADS)

    Shikayama, Toru; Takaki, Mamoru; Ohto, Motomichi; Tsuji, Teruo; Kosaka, Takashi; Matsui, Nobuyuki

    This paper presents the loss analysis and reduction of Slotless Permanent Magnet Motors (SLPMM). The resistance and current at the inverter carrier frequency are introduced, by which loss generated by the high frequency current (carrier loss) can be separated from the total loss. The experimental studies using 200W, 3000min-1 SLPMM with halbach magnet array show the effective reduction of carrier loss. Finally, the experimental studies using the SLPMM with a series reactor proved the proposed loss analysis.

  9. 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.

  10. Polarization-independent electro-optic depolarizer

    NASA Astrophysics Data System (ADS)

    Heismann, F.; Tokuda, K. L.

    1995-05-01

    We demonstrate a compact electro-optic polarization scrambler that depolarizes arbitrarily polarized light with less than 2.5% residual degree of polarization and variable depolarization times in the microsecond to millisecond range. The integrated-optic depolarizer is fabricated on lithium niobate and operates with a single-mode waveguide designed for a 1.5- mu m wavelength. The scrambler introduces negligible intensity modulation of less than 1.6% in the depolarized output light.

  11. 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.

  12. 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.

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

    PubMed

    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. PMID:26927390

  14. Depolarization Alters Phenotype, Maintains Plasticity of Predifferentiated Mesenchymal Stem Cells

    PubMed Central

    Sundelacruz, Sarah; Levin, Michael

    2013-01-01

    Although adult stem cell transplantation has been implemented as a therapy for tissue repair, it is limited by the availability of functional adult stem cells. A potential approach to generate stem and progenitor cells may be to modulate the differentiated status of somatic cells. Therefore, there is a need for a better understanding of how the differentiated phenotype of mature cells is regulated. We hypothesize that bioelectric signaling plays an important role in the maintenance of the differentiated state, as it is a functional regulator of the differentiation process in various cells and tissues. In this study, we asked whether the mature phenotype of osteoblasts and adipocytes derived from human mesenchymal stem cells (hMSCs) could be altered by modulation of their membrane potential. hMSC-derived osteoblasts and adipocytes were depolarized by treatment with ouabain, a Na+/K+ ATPase inhibitor, or by treatment with high concentrations of extracellular K+. To characterize the effect of voltage modulation on the differentiated state, the depolarized cells were evaluated for (1) the loss of differentiation markers; (2) the up-regulation of stemness markers and stem properties; and (3) differences in gene expression profiles in response to voltage modulation. hMSC-derived osteoblasts and adipocytes exhibited significant down-regulation of bone and fat tissue markers in response to depolarization, despite the presence of differentiation-inducing soluble factors, suggesting that bioelectric signaling overrides biochemical signaling in the maintenance of cell state. Suppression of the osteoblast or adipocyte phenotype was not accompanied by up-regulation of genes associated with the stem state. Thus, depolarization does not activate the stem cell genetic signature and, therefore, does not induce a full reprogramming event. However, after transdifferentiating the depolarized cells to evaluate for multi-lineage potential, depolarized osteoblasts demonstrated improved

  15. Magnetic correlations in the magnetocaloric materials Mn3GaC and Mn3GaC0.85N0.15 studied by neutron polarization analysis and neutron depolarization

    NASA Astrophysics Data System (ADS)

    Çakr, Ö.; Acet, M.; Farle, M.; Wildes, A.

    2016-04-01

    Partially substituting carbon by nitrogen in the antiperovskite compound Mn3GaC increases the first order antiferromagnetic/ferromagnetic transition temperature and at the same time causes the high-temperature long-range ferromagnetism to weaken. To show that the weakening is related to the diminishing of ferromagnetic domain formation, we undertake neutron depolarization and neutron polarization analysis experiments on Mn3GaC and Mn3GaC0.85N0.15. Polarization analysis experiments show that strong ferromagnetic correlations are present at high temperatures in the paramagnetic states of both Mn3GaC and Mn3GaC0.85N0.15 and that these correlations vanish in the antiferromagnetic state. Neutron depolarization studies show that above the first order transition temperature, ferromagnetic domain formation is present in Mn3GaC but is absent in Mn3GaC0.85N0.15. The relationship between ferromagnetic domain formation and transitional hysteresis is brought forward for these two important magnetocaloric materials.

  16. Thermally stimulated depolarization current analysis for the dielectric aging of Mn and V-codoped BaTiO3 multi layer ceramic capacitor

    NASA Astrophysics Data System (ADS)

    Yoon, Seok-Hyun; Park, Jae-Sung; Kim, Sang-Hyuk; Kim, Doo-Young

    2013-07-01

    Dielectric aging of Mn and V-codoped BaTiO3 was investigated. The increase of V concentration had little influence on aging, whereas that of Mn increased it. Thermally stimulated depolarization current (TSDC) of low Mn concentration specimen showed one peak, whereas Mn-increased specimen showed two peaks. The first and second peak is supposed to be caused by the phase transition of the undoped core region and the defect dipole of Mn such as MnTi″-VO•• or MnTi'-VO••, respectively. High TSDC associated with the defect dipole of Mn and significant aging rate experimentally demonstrates that the dielectric aging is controlled by the defect dipole.

  17. Depolarized FRET (depolFRET) on the cell surface: FRET control by photoselection.

    PubMed

    Bene, László; Gogolák, Péter; Ungvári, Tamás; Bagdány, Miklós; Nagy, István; Damjanovich, László

    2016-02-01

    Sensitivity of FRET in hetero- and homo-FRET systems on the photoselected orientation distribution of donors has been proven by using polarized and depolarized light for excitation. FRET as well as donor and acceptor anisotropies have been simultaneously measured in a dual emission-polarization scheme realized in a conventional flow cytometer by using single laser excitation and applying fluorophore-conjugated mAbs against the MHCI and MHCII cell surface receptors. Depolarization of the originally polarized light have been achieved by using crystal depolarizers based on Cornu's principle, a quarter-wave plate for circular polarization, and a parallel beam splitter acting as a diagonal-polarizer for dual-polarization excitation. Simultaneous analysis of intensity-based FRET efficiency and acceptor depolarization equivocally report that depolarization of light may increase FRET in an amount depending on the acceptor-to-donor concentration ratio. Acceptor depolarization turned to be more sensitive to FRET than donor hyper-polarization and even than intensity-based FRET efficiency. It can be used as a sensitive tool for monitoring changes in the dynamics of the donor-acceptor pairs. The basic observations of FRET enhancement and increased acceptor depolarization obtained for hetero-FRET are paralleled by analog observations of homo-FRET enhancements under depolarized excitation. In terms of the orientation factor for FRET, the FRET enhancements on depolarization in the condition of the macroscopically isotropic orientation distributions such as those of the cell surface bound fluorophores report on the presence of local orientation mismatches of the donor and acceptor preventing the optimal FRET in the polarized case, which may be eliminated by the excitation depolarization. A theory of fluorescence anisotropy for depolarized excitation is also presented. PMID:26657258

  18. 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.

  19. 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.

  20. Fundus depolarization imaging with GDx VCC scanning laser polarimeter and depolarization characteristics of normal eyes

    NASA Astrophysics Data System (ADS)

    Zhou, Qienyuan; Leder, Henry A.; Lo, Barrick P.; Reed, Geradus C.; Knighton, Robert W.; Cousins, Scott W.

    2009-02-01

    GDx VCC is a confocal scanning laser polarimeter (SLP) developed to assess the retinal nerve fiber layer (RNFL) of the eye based on measurement of the phase retardation in the backscattered light from the fundus. In addition to the phase retardation measurement, a depolarization measurement is readily available from the same image series. We hypothesize that the depolarized light in the GDx signal consists of backscattering from the retinal pigment epithelium (RPE) and the RPE-Bruch's membrane junction, and further, that subRPE deposits contribute to the depolarized backscattered light in proportion to their thickness. Therefore, a quantitative macular depolarization map will provide information about both spatial distribution and heterogeneity of the RPE structure and deposit thickness. Ultimately we predict that depolarization mapping will significantly increase the positive predictive power to identify early dry AMD eyes. In this paper, depolarization measurements in normal eyes and age related changes are reported. Data collection was performed at the Duke University Eye Center. A commercial GDx VCC system was modified with a central fixation target and, instead of depolarized light intensity images, normalized depolarization images were derived and saved in the database. Macular depolarization was observed to increase with age in normal eyes at a rate of 0.27%/yr.

  1. 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.

  2. Relative entropy convergence for depolarizing channels

    NASA Astrophysics Data System (ADS)

    Müller-Hermes, Alexander; Stilck França, Daniel; Wolf, Michael M.

    2016-02-01

    We study the convergence of states under continuous-time depolarizing channels with full rank fixed points in terms of the relative entropy. The optimal exponent of an upper bound on the relative entropy in this case is given by the log-Sobolev-1 constant. Our main result is the computation of this constant. As an application, we use the log-Sobolev-1 constant of the depolarizing channels to improve the concavity inequality of the von Neumann entropy. This result is compared to similar bounds obtained recently by Kim and we show a version of Pinsker's inequality, which is optimal and tight if we fix the second argument of the relative entropy. Finally, we consider the log-Sobolev-1 constant of tensor-powers of the completely depolarizing channel and use a quantum version of Shearer's inequality to prove a uniform lower bound.

  3. 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.

  4. Localization of nerve depolarization with magnetic stimulation.

    PubMed

    Odderson, I R; Halar, E M

    1992-06-01

    The specific location on the magnetic stimulation (MS) coil that may correspond to the area of nerve depolarization has not been determined. In order to localize such an area, MS with 9-cm and 5-cm diameter coils was compared with conventional percutaneous electric stimulation (ES). On the 9-cm coil the distribution of points of nerve depolarization corresponded to that quarter of the coil which was placed over and parallel to the median nerve, whereas on the 5-cm coil, this area also extended outside the coil. The points of median nerve depolarization with MS were distributed over a distance of 7 cm on the stimulator head and was nearly identical for the 2 coil sizes at the wrist and elbow. Ulnar nerve costimulation was less frequent with the smaller coil at the wrist. A calculated reference point on the coil is suggested for more accurate NCV determinations. PMID:1508235

  5. 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.

  6. An analysis of item gains and losses in retroactive interference.

    PubMed

    Burns, D J; Gold, D E

    1999-07-01

    The repeated-testing paradigm is used to study both retroactive interference and hypermnesia (the improvement in memory across repeated tests). Considerable theoretical progress has been made by separately analyzing the 2 components of hypermnesia: the recovery of previously unrecalled items on later tests (item gains) and the forgetting of previously recalled items on later tests (item losses). Item gains increase with increases in item-specific processing, whereas item losses decrease with increases in relational processing. The authors suggest that separate analysis of item gains and losses in retroactive interference research may also prove fruitful. Three experiments showed that an interpolated list affects item gains but not losses, whereas processing similarity between the target and interpolated lists affects losses but not gains. These results are interpreted within the relational-item-specific processing framework. PMID:10439504

  7. 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

  8. 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.

  9. 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.

  10. Analysis of loss mechanisms in polycrystalline thin film solar cells

    NASA Astrophysics Data System (ADS)

    Sites, J. R.

    1990-08-01

    Our goal for thin-film polycrystalline solar cell analysis was to increase the useful information extracted from relatively straightforward electrical measurements. The strategy was to (1) systematize measurements and reporting, (2) organize results in terms of quantitative values for individual sources of current and voltage loss, and (3) evaluate possible analytical techniques to enhance precision and avoid pitfalls, and (4) insist on a viable physical explanation of each loss mechanism. Current-voltage, quantum efficiency, and capacitance measurements on CuInSe2 and CdTe solar cells from a variety of sources have been analyzed. In many cases losses were identified that may be lessened relatively easily. However, the operating voltage loss due to excessive forward recombination current throughout the depletion region remains the primary obstacle to efficiencies competitive with single crystal cells.

  11. Iron Loss Analysis of IPM Motor Considering Carrier Harmonics

    NASA Astrophysics Data System (ADS)

    Yamazaki, Katsumi; Seto, Yoshiaki; Tanida, Makoto

    In this paper, we investigate the iron loss of interior permanent magnet motors driven by PWM inverters using electromagnetic field analysis. Following 4 methods are applied: (1) Current input finite element method neglecting the carrier harmonics. (2) Voltage input finite element analysis neglecting carrier harmonics. (3) Current input finite element method with the measured armature current waveforms including the carrier harmonics. (4) Voltage input finite element method with the theoretical voltage waveforms of the PWM inverter. The calculated results are compared with the experimental ones. It is clarified that the accuracy of the calculated results are improved by considering the carrier harmonics and that the method (4) can estimate the iron loss of the IPM motor accurately before manufacturing. The variation of the iron loss components due to the driving condition is also clarified.

  12. X-RAY EMISSION ANALYSIS: SAMPLE LOSSES DURING EXCITATION

    EPA Science Inventory

    Many samples of atmospheric aerosols and biological materials containing volatile or unstable species are now being examined by X-ray emission analysis, and loss of these species by sample heating is a critical consideration. The amount of heat energy deposited in a sample by the...

  13. 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…

  14. 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.

  15. 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.

  16. 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.

  17. Ultraviolet scattering propagation modeling: analysis of path loss versus range.

    PubMed

    Drost, Robert J; Moore, Terrence J; Sadler, Brian M

    2013-11-01

    Modeling of the complex atmospheric propagation of deep-ultraviolet (UV) radiation is important for applications such as non-line-of-sight (NLOS) UV communications. Building upon prior work in which it was observed that short-range, singly scattered NLOS path loss varies linearly with range, we formalize this relationship, generalizing it to consider any order of scattering and more-general system characteristics. In particular, we derive the approximate relationship PL[proportionality]r(2-n) between path loss PL and range r for nth-order scattered radiation, and investigate the region of validity of this approximation. Insight arising from the analysis can be invaluable in the development and study of UV systems, as demonstrated by numerical results that illustrate implications of the analysis. PMID:24322923

  18. 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.

  19. Losses as modulators of attention: review and analysis of the unique effects of losses over gains.

    PubMed

    Yechiam, Eldad; Hochman, Guy

    2013-03-01

    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 major inconsistencies remain. First, recent empirical evidence fails to demonstrate that people avoid incentive structures that carry equivalent gains and losses. Second, findings in experience-based decision tasks indicate that following losses, increased arousal is observed simultaneously with no behavioral loss aversion. To account for these findings, we developed an attention-allocation model as a comprehensive framework for the effect of losses. According to this model losses increase on-task attention, thereby enhancing the sensitivity to the reinforcement structure. In the current article we examine whether this model can account for a broad range of empirical phenomena involving losses. We show that as predicted by the attentional model, asymmetric effects of losses on behavior emerge where gains and losses are presented separately but not concurrently. Yet, even in the absence of loss aversion, losses have distinct effects on performance, arousal, frontal cortical activation, and behavioral consistency. The attentional model of losses thus explains some of the main inconsistencies in previous studies of the effect of losses. PMID:22823738

  20. Dynamic depolarization in plasmonic metal nanoparticles

    NASA Astrophysics Data System (ADS)

    Apell, S. Peter; Zorić, Igor; Langhammer, Christoph

    2016-08-01

    At very low photon energies most metals have a very large and negative dielectric function. For the response of a metal nanoparticle to an external field in this limit, this means that the particular choice of metal does not matter and the localized surface plasmon energy mainly depends on the shape and size of the particle. Here, we present a theoretical framework to describe this situation and unearth the interplay between the depolarization factor of the problem at hand and the dielectric function of the particle. Available experimental results compare favorably with our theoretical framework.

  1. 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. PMID:26362075

  2. Characterization of depolarizing optical media by means of the entropy factor: application to biological tissues

    NASA Astrophysics Data System (ADS)

    Pereda Cubián, David; Arce Diego, José Luis; Rentmeesters, Raf

    2005-01-01

    Polarized light imaging is a potential tool to obtain an adequate description of the properties of depolarizing media such as biological tissues. In many biomedical applications, for instance, dermatology, ophthalmology, or urology, imaging polarimetry provides a noninvasive diagnosis of a wide range of disease states, and, likewise, it could be applied to the study of internal tissues though the use of endoscopes that use optical fibers. We introduce an algebraic method, based on the Mueller-coherence matrix, for a clearer analysis of the polarization characteristics of depolarizing media via the entropy factor. First-order errors introduced by the measurement system are corrected. Entropy defines three kinds of media according to their depolarizing behavior, and several examples corresponding to each region are shown. The calculation of this factor provides clearer information than that provided by the traditional Mueller matrix in the analysis of biological tissue properties by polarization measurement techniques.

  3. 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.

  4. 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.

  5. 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.

  6. 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…

  7. Tune space manipulations in jumping depolarizing resonances

    SciTech Connect

    Ratner, L.G.; Ahrens, L.A.

    1987-01-01

    In February 1986, the AGS polarized beam reached a momentum of 22 GeV/c with a 45% polarization and an intensity of 1 to 2 x 10/sup 10/ polarized protons per pulse at a repetition rate of 2.1 seconds. In order to achieve this, one had to overcome the effect of some 40 depolarizing resonances. In our first commissioning run in 1984, we had reached 16.5 GeV/c using, with suitable modifications, the conventional techniques first used at the Argonne ZGS. This worked well, but we found that the fast tune shifts required to cross the intrinsic depolarizing resonances were causing an increase in beam emittance which led to the need for stronger corrections later in the cycle and to diminished extraction efficiency. For the 1986 run, we were prepared to minimize this emittance growth by the application of slow quadrupole pulses to change the region in tune space in which we operated the first tune quads. In this paper we give a brief description of the conventional corrections, but our main emphasis is on the descriptions of tune space manipulations.

  8. Practical depolarization-ratio-based inversion procedure: lidar measurements of the Eyjafjallajökull ash cloud over the Netherlands.

    PubMed

    Donovan, David Patrick; Apituley, Arnoud

    2013-04-10

    In this paper we present a technique for estimating optical backscatter and extinction profiles using lidar, which exploits the difference between the observed linear volume depolarization ratio at 355 nm and the corresponding expected aerosol-only depolarization ratio. The technique is specific to situations where a single strongly depolarizing species is present and the associated linear particulate depolarization ratio may be presumed to be known to within a reasonable degree of accuracy (on the order of 10%). The basic principle of the technique is extended to deal with situations where a depolarizing fraction is mixed with nondepolarizing aerosol. In general, since the relative depolarization interchannel calibration is much more stable than the absolute system calibration, the depolarization-based technique is easier to implement than conventional techniques that require a profile-by-profile calibration or, equivalently, an identification of aerosol-free altitude intervals. This in particular allows for unattended data analysis and makes the technique well-suited to be part of a broader (volcanic ash) surveillance system. The technique is demonstrated by applying it to the analysis of aerosol layers resulting from the 2010 eruptions of the Eyjafjallajökull volcano in Iceland. The measurements were made at the Cabauw remote-sensing site in the central Netherlands. By comparing the results of the depolarization-based inversion with a more conventional manual inversion procedure as well as Raman lidar results, it is demonstrated that the technique can be successfully applied to the particular case of 355 nm depolarization lidar volcanic ash soundings, including cases in which the ash is mixed with nondepolarizing aerosol. PMID:23670771

  9. 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.

  10. 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.

  11. Mitochondrial depolarization and asystole in the globally ischemic rabbit heart: coordinated response to interventions affecting energy balance

    PubMed Central

    Venable, Paul W.; Sciuto, Katie J.; Warren, Mark; Taylor, Tyson G.; Garg, Vivek; Shibayama, Junko

    2014-01-01

    Mitochondrial membrane potential (ΔΨm) depolarization has been implicated in the loss of excitability (asystole) during global ischemia, which is relevant for the success of defibrillation and resuscitation after cardiac arrest. However, the relationship between ΔΨm depolarization and asystole during no-flow ischemia remains unknown. We applied spatial Fourier analysis to confocally recorded fluorescence emitted by ΔΨm-sensitive dye tetramethylrhodamine methyl ester. The time of ischemic ΔΨm depolarization (tmito_depol) was defined as the time of 50% decrease in the magnitude of spectral peaks reflecting ΔΨm. The time of asystole (tasys) was determined as the time when spontaneous and induced ventricular activity ceased to exist. Interventions included tachypacing (150 ms), myosin II ATPase inhibitor blebbistatin (heart immobilizer), and the combination of blebbistatin and the inhibitor of glycolysis iodoacetate. In the absence of blebbistatin, confocal images were obtained during brief perfusion with hyperkalemic solution and after the contraction failed between 7 and 15 min of ischemia. In control, tmito_depol and tasys were 24.4 ± 6.0 and 26.0 ± 5.0 min, respectively. Tachypacing did not significantly affect either parameter. Blebbistatin dramatically delayed tmito_depol and tasys (51.4 ± 8.6 and 45.7 ± 5.3 min, respectively; both P < 0.0001 vs. control). Iodoacetate combined with blebbistatin accelerated both events (tmito_depol, 12.7 ± 1.8 min; and tasys, 6.5 ± 1.1 min; both P < 0.03 vs. control). In all groups pooled together, tasys was strongly correlated with tmito_depol (R2 = 0.845; P < 0.0001). These data may indicate a causal relationship between ΔΨm depolarization and asystole or a similar dependence of the two events on energy depletion during ischemia. Our results urge caution against the use of blebbistatin in studies addressing pathophysiology of myocardial ischemia. PMID:25552307

  12. A 20 Ghz Depolarization Experiment Using the ATS-6 Satellite

    NASA Technical Reports Server (NTRS)

    Bostian, C. W.; Manus, E. A.; Marshall, R. E.; Pendrak, H. N.; Stutzman, W. L.; Wiley, P. H.; Kauffman, S. R.

    1975-01-01

    A depolarization experiment using the 20 GHz downlink from the ATS-6 satellite was described. The following subjects were covered: (1) an operational summary of the experiment, (2) a description of the equipment used with emphasis on improvements made to the signal processing receiver used with the ATS-5 satellite, (3) data on depolarization and attenuation in one snow storm and two rain storms at 45 deg elevation, (4) data on low angle propagation, (5) conclusions about depolarization on satellite paths, and (6) recommendations for the depolarization portion of the CTS experiment.

  13. Rod-like cholesterol micelles in aqueous solution studied using polarized and depolarized dynamic light scattering.

    PubMed Central

    Castanho, M A; Brown, W; Prieto, M J

    1992-01-01

    Micelles of cholesterol in aqueous solution have been investigated using polarized and depolarized dynamic light scattering. They are shown to be highly extended and characterized by a narrow size distribution. It is shown that a rod-like model is applicable with length, L = 580 nm. Determination of the rotational diffusion coefficient by analysis of the autocorrelation function gave a value of theta = 150 s-1, which is close to the calculated value for the rod with this dimension. Depolarized dynamic light scattering measurements as a function of angle gave a value of 110 s-1. PMID:1489905

  14. 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.

  15. Analysis of loss of heterozygosity in circulating DNA.

    PubMed

    Nakamura, Takeshi; Sunami, Eiji; Nguyen, Tuny; Hoon, Dave S B

    2009-01-01

    Analysis of genetic altera tion in circulating DNA can have clinical utility in predicting disease outcome. Loss of heterozygosity (LOH) of DNA microsatellites has been shown to occur commonly among all chromosomes in various cancers, such as melanoma, breast cancer, and lung cancer. In this protocol, we focused on the utility of LOH of microsatellite biomarkers for detection of analyzing circulating DNA. The protocol describes how PCR is performed on each patient's paired DNA samples (normal lymphocyte DNA and serum DNA) using specific microsatellite biomarkers followed by post-PCR product analysis using capillary array electrophoresis (CAE). The utility of CAE is due to its digitalization and accuracy of the post-PCR product results. PMID:19381958

  16. 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

  17. Valley depolarization in monolayer WSe2.

    PubMed

    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

  18. 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.

  19. Experimental verification of depolarization effects in bioelectrical impedance measurement.

    PubMed

    Chen, Xiaoyan; Lv, Xinqiang; Du, Meng

    2014-01-01

    The electrode polarization effects on bioelectrical impedance measurement at low-frequency cannot be ignored. In this paper, the bioelectrical data of mice livers are measured to specify the polarization effects on the bio-impedance measurement data. We firstly introduce the measurement system and methodology. Using the depolarization method, the corrected results are obtained. Besides, the specific effects of electrode polarization on bio-impedance measurement results are investigated using comparative analysis of the previous and posterior correction results from dielectric spectroscopy, Cole-Cole plot, conductivity and spectroscopy of dissipation tangent. Experimental results show that electrode polarization has a significant influence on the characteristic parameters of mouse liver tissues. To be specific, we see a low-frequency limit resistance R0 increase by 19.29%, a reactance peak XP increase by 8.50%, a low-frequency limit conductivity Kl decrease by 17.65% and a dissipation peak tangent decrease by 160%. PMID:25227082

  20. 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

  1. 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.

  2. [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. PMID:23928069

  3. Nuclear depolarization and absolute sensitivity in magic-angle spinning cross effect dynamic nuclear polarization.

    PubMed

    Mentink-Vigier, Frédéric; Paul, Subhradip; Lee, Daniel; Feintuch, Akiva; Hediger, Sabine; Vega, Shimon; De Paëpe, Gaël

    2015-09-14

    Over the last two decades solid state Nuclear Magnetic Resonance has witnessed a breakthrough in increasing the nuclear polarization, and thus experimental sensitivity, with the advent of Magic Angle Spinning Dynamic Nuclear Polarization (MAS-DNP). To enhance the nuclear polarization of protons, exogenous nitroxide biradicals such as TOTAPOL or AMUPOL are routinely used. Their efficiency is usually assessed as the ratio between the NMR signal intensity in the presence and the absence of microwave irradiation εon/off. While TOTAPOL delivers an enhancement εon/off of about 60 on a model sample, the more recent AMUPOL is more efficient: >200 at 100 K. Such a comparison is valid as long as the signal measured in the absence of microwaves is merely the Boltzmann polarization and is not affected by the spinning of the sample. However, recent MAS-DNP studies at 25 K by Thurber and Tycko (2014) have demonstrated that the presence of nitroxide biradicals combined with sample spinning can lead to a depolarized nuclear state, below the Boltzmann polarization. In this work we demonstrate that TOTAPOL and AMUPOL both lead to observable depolarization at ≈110 K, and that the magnitude of this depolarization is radical dependent. Compared to the static sample, TOTAPOL and AMUPOL lead, respectively, to nuclear polarization losses of up to 20% and 60% at a 10 kHz MAS frequency, while Trityl OX63 does not depolarize at all. This experimental work is analyzed using a theoretical model that explains how the depolarization process works under MAS and gives new insights into the DNP mechanism and into the spin parameters, which are relevant for the efficiency of a biradical. In light of these results, the outstanding performance of AMUPOL must be revised and we propose a new method to assess the polarization gain for future radicals. PMID:26235749

  4. Analysis of power loss in Ni-Zn ferrites

    NASA Astrophysics Data System (ADS)

    Kondo, K.; Chiba, T.; Yamada, S.; Otsuki, E.

    2000-05-01

    The power loss (Pcv) was analyzed by combining two methods. The first, Pcv, is divided into hysteresis loss (Ph) and residual loss (Pr) from the frequency dependence of the power loss according to the method of Otsuki et al., and, second, the loss factors are attributed to domain wall motion (Pw) and the rotation magnetization (Prot) by adapting the method proposed by Visser et al. It was found that Pw coincides with Ph in the lower frequency range, but the difference between them becomes significant as frequency goes up. The higher value of Pw, in comparison with Ph in the higher frequency range, can be attributed to the enhancement of loss due to the dynamic motion of the domain wall (Pwd) by raising the frequency. The hysteresis loss dominates Pcv in the frequency range below 500 kHz, while Pwd becomes predominant factor in the higher frequency range more than 500 kHz.

  5. Fluorescence depolarization measurements on oriented membranes.

    PubMed Central

    Adler, M; Tritton, T R

    1988-01-01

    We describe the theory and experimental application of fluorescence depolarization measurements on small molecules bound to oriented phospholipid bilayers. The results yield insight into both the orientation and the rotational motion of fluorophores in a membrane environment. To accomplish this the angular distribution of polarized fluorescence intensities is measured on a membrane preparation consisting of stacked phospholipid bilayers oriented in a known coordinate system. Considerably more information is available from this data than in comparable solution phase measurements. Three parameters are derived from the data: the rate of rotational diffusion and the second and fourth degree order parameters. These latter two parameters provide an assessment of the average distribution of fluorophore orientation in the membrane bilayer. The data have been carefully examined for systematic experimental artifacts and new protocols are presented which help to eliminate errors that have not been amply treated in the past. We present data for two types of fluorescent molecules: (a) conventional membrane probes like diphenylhexatriene, perylene and anthroyloxy fatty acids; and (b) the anticancer agent adriamycin and several congeneric anthracycline antibiotics. The results show that the hydrocarbon core of membranes is more rigid than previously thought, particularly above the thermal phase transition temperature. We also show that the orientation of small molecules is sensitive to both the phospholipid composition and to the interaction of specific functional groups with the lipid bilayer. The results are discussed in terms of energetic models describing the general patterns for the binding of small molecules to biological membranes. Images FIGURE 1 PMID:3165033

  6. 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.

  7. Diffusive transfer of polarized 3He gas through depolarizing magnetic gradients

    NASA Astrophysics Data System (ADS)

    Maxwell, J. D.; Epstein, C. S.; Milner, R. G.

    2015-03-01

    Transfer of polarized 3He gas across spatially varying magnetic fields will facilitate a new source of polarized 3He ions for particle accelerators. In this context, depolarization of atoms as they pass through regions of significant transverse field gradients is a major concern. To understand these depolarization effects, we have built a system consisting of a Helmholtz coil pair and a solenoid, both with central magnetic fields of order 30 gauss. The atoms are polarized via metastability exchange optical pumping in the Helmholtz coil and are in diffusive contact via a glass tube with a second test cell in the solenoid. We have carried out measurements of the spin relaxation during transfer of polarization in 3He at 1 torr by diffusion. We explore the use of measurements of the loss of polarization taken in one cell to infer the polarization in the other cell.

  8. Mitochondrial depolarization and electrophysiological changes during ischemia in the rabbit and human heart.

    PubMed

    Sulkin, Matthew S; Boukens, Bas J; Tetlow, Megan; Gutbrod, Sarah R; Ng, Fu Siong; Efimov, Igor R

    2014-10-15

    Instability of the inner mitochondrial membrane potential (ΔΨm) has been implicated in electrical dysfunction, including arrhythmogenesis during ischemia-reperfusion. Monitoring ΔΨm has led to conflicting results, where depolarization has been reported as sporadic and as a propagating wave. The present study was designed to resolve the aforementioned difference and determine the unknown relationship between ΔΨm and electrophysiology. We developed a novel imaging modality for simultaneous optical mapping of ΔΨm and transmembrane potential (Vm). Optical mapping was performed using potentiometric dyes on preparations from 4 mouse hearts, 14 rabbit hearts, and 7 human hearts. Our data showed that during ischemia, ΔΨm depolarization is sporadic and changes asynchronously with electrophysiological changes. Spatially, ΔΨm depolarization was associated with action potential duration shortening but not conduction slowing. Analysis of focal activity indicated that ΔΨm is not different within the myocardium where the focus originates compared with normal ventricular tissue. Overall, our data suggest that during ischemia, mitochondria maintain their function at the expense of sarcolemmal electrophysiology, but ΔΨm depolarization does not have a direct association to ischemia-induced arrhythmias. PMID:25128175

  9. 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.

  10. 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.

  11. Depolarization artifacts in dual rotating-compensator Mueller matrix ellipsometry

    NASA Astrophysics Data System (ADS)

    Li, Weiqi; Zhang, Chuanwei; Jiang, Hao; Chen, Xiuguo; Liu, Shiyuan

    2016-05-01

    Noticeable depolarization effects are observed in the measurement of the air using an in-house developed dual rotating-compensator Mueller matrix ellipsometer. We demonstrate that these depolarization effects are essentially artifacts and mainly induced when the compensator with wavelength-dependent optical properties is integrated with the finite bandwidth detector. We define a general formula to represent the actual Mueller matrix of the compensator by taking into account the depolarization artifacts. After incorporating this formula into the system model, a correction method is further proposed, and consequently, improved accuracy can be achieved in the Mueller matrix measurement.

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

    PubMed

    Dreier, Jens P; 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

  13. 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.

  14. 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. PMID:21895184

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  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. 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.

  18. 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.

  19. A deterministic method for studying depolarization in turbid media

    NASA Astrophysics Data System (ADS)

    Clark, Julia P.

    2016-05-01

    There are a number of interesting experimental and Monte Carlo results regarding the persistence of polarization in turbid media; however, there is not a good theoretical understanding of this phenomenon. These results include circular polarization memory in strongly scattering anisotropic media and the impact of polydisperse scatterers on the depolarization rate. In this work we use the spectrum of the discretized vector radiative transport equation to investigate to study circular depolarization in strongly scattering media.

  20. Depolarization effects in the active remote sensing of random media

    NASA Technical Reports Server (NTRS)

    Zuniga, M.; Kong, J. A.; Tsang, L.

    1980-01-01

    Backscattering cross sections for depolarization are derived for the active remote sensing of a two-layer random medium. It is shown that the depolarization effects arise as a second-order term in albedo under the Born approximation. The results of the backscattering cross sections are illustrated as functions of frequency and incident angles and used to match experimental data collected from a vegetation field.

  1. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  3. Parameter uncertainty analysis for the annual phosphorus loss estimator (APLE) model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  4. Impaired neurovascular coupling to ictal epileptic activity and spreading depolarization in a patient with subarachnoid hemorrhage: possible link to blood-brain barrier dysfunction.

    PubMed

    Winkler, Maren K L; Chassidim, Yoash; Lublinsky, Svetlana; Revankar, Gajanan S; Major, Sebastian; Kang, Eun-Jeung; Oliveira-Ferreira, Ana I; Woitzik, Johannes; Sandow, Nora; Scheel, Michael; Friedman, Alon; Dreier, Jens P

    2012-11-01

    Spreading depolarization describes a sustained neuronal and astroglial depolarization with abrupt ion translocation between intraneuronal and extracellular space leading to a cytotoxic edema and silencing of spontaneous activity. Spreading depolarizations occur abundantly in acutely injured human brain and are assumed to facilitate neuronal death through toxic effects, increased metabolic demand, and inverse neurovascular coupling. Inverse coupling describes severe hypoperfusion in response to spreading depolarization. Ictal epileptic events are less frequent than spreading depolarizations in acutely injured human brain but may also contribute to lesion progression through increased metabolic demand. Whether abnormal neurovascular coupling can occur with ictal epileptic events is unknown. Herein we describe a patient with aneurysmal subarachnoid hemorrhage in whom spreading depolarizations and ictal epileptic events were measured using subdural opto-electrodes for direct current electrocorticography and regional cerebral blood flow recordings with laser-Doppler flowmetry. Simultaneously, changes in tissue partial pressure of oxygen were recorded with an intraparenchymal oxygen sensor. Isolated spreading depolarizations and clusters of recurrent spreading depolarizations with persistent depression of spontaneous activity were recorded over several days followed by a status epilepticus. Both spreading depolarizations and ictal epileptic events where accompanied by hyperemic blood flow responses at one optode but mildly hypoemic blood flow responses at another. Of note, quantitative analysis of Gadolinium-diethylene-triamine-pentaacetic acid (DTPA)-enhanced magnetic resonance imaging detected impaired blood-brain barrier integrity in the region where the optode had recorded the mildly hypoemic flow responses. The data suggest that abnormal flow responses to spreading depolarizations and ictal epileptic events, respectively, may be associated with blood-brain barrier

  5. Glutathione Oxidation as a Trigger of Mitochondrial Depolarization and Oscillation in Intact Hearts

    PubMed Central

    Slodzinski, M.K.; Aon, A.M.; O’Rourke, B.

    2008-01-01

    Depolarization of the mitochondrial inner membrane potential (ΔΨm) associated with oxidative stress is thought to be a critical factor in cardiac dysfunction and cell injury following ischemia-reperfusion or exposure to cardiotoxic agents. In isolated cardiomyocytes, mitochondrially-generated reactive oxygen species (ROS) can readily trigger cell-wide collapse or oscillations of ΔΨm but is it not known whether these phenomena scale to the level of the whole heart. Here we utilize two-photon laser scanning fluorescence microscopy to track ΔΨm, ROS, and reduced glutathione (GSH) levels in intact perfused guinea-pig hearts subjected to ischemia-reperfusion or GSH depletion with the thiol oxidizing agent diamide. Exposure to oxidative stress by either method provoked heterogeneous ΔΨm depolarization and occasional oscillation in clusters of myocytes in the epicardium in association with increased mitochondrial ROS production. Furthermore, the whole heart oxidative stress dramatically increased the sensitivity of seemingly quiescent cells to ΔΨm depolarization induced by a localized laser flash. These effects were directly correlated with depletion of the intracellular GSH pool. Unexpectedly, hearts perfused with nominally Ca2+-free solution or those switched from 0.5 mM Ca2+ to nominally Ca2+-free solution also displayed heterogeneous ΔΨm depolarization and oscillation, in parallel with net oxidation of the GSH pool. The findings demonstrate that metabolic heterogeneity initiated by mitochondrial ROS-induced ROS release is present in the intact heart, and that the redox state of the glutathione pool is a key determinant of loss of ΔΨm. PMID:18760283

  6. Elastic depolarization and polarization transfer in CN(A2Π, v = 4)+Ar collisions

    NASA Astrophysics Data System (ADS)

    Ballingall, Iain; Rutherford, Michael F.; McKendrick, Kenneth G.; Costen, Matthew L.

    2010-04-01

    Rate constants for collisional loss and transfer of population and rotational angular momentum alignment have been determined for the CN(A2Π, v = 4)+Ar system. Aligned samples of CN(A2Π, v = 4, F 1, j = 1.5-23.5e) were prepared by optical pumping on the A-X(4,0) band. Their evolution was observed using Doppler-resolved frequency-modulated spectroscopy in stimulated emission on the A-X(4,2) band. State-resolved total population removal rate constants, and state-to-state rotational energy transfer (RET) rate constants, are found to be in excellent agreement with previous experimental measurements and theoretical predictions for the v = 3 level. Rapid elastic depolarization of rotational alignment was observed for j = 1.5-6.5, with an average rate constant of 1.1 × 10-10 cm3 s-1. This declines with increasing j, reaching zero within experimental error for j = 23.5. The polarization transfer efficiency of the initially created alignment in state-to-state RET was also determined for the selected initial state j = 6.5, F 1, e. Substantial depolarization of the alignment was observed for small Δj transitions. Alignment transfer efficiencies ranged from 0.55 ± 0.06 for Δj = -1, to 0.32 ± 0.08 for Δj = +3. These measurements are discussed with reference to recent experimental and theoretical advances on collisional depolarization of related open-shell species. We suggest that the surprisingly efficient collisional depolarization observed may be the result of the multiple potential energy surfaces involved in this system.

  7. 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.

  8. 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.

  9. 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.

  10. Laboratory investigations of mineral dust near-backscattering depolarization ratios

    NASA Astrophysics Data System (ADS)

    Järvinen, E.; Kemppinen, O.; Nousiainen, T.; Kociok, T.; Möhler, O.; Leisner, T.; Schnaiter, M.

    2016-07-01

    Recently, there has been increasing interest to derive the fractions of fine- and coarse-mode dust particles from polarization lidar measurements. For this, assumptions of the backscattering properties of the complex dust particles have to be made either by using empirical data or particle models. Laboratory measurements of dust backscattering properties are important to validate the assumptions made in the lidar retrievals and to estimate their uncertainties. Here, we present laboratory measurements of linear and circular near-backscattering (178°) depolarization ratios of over 200 dust samples measured at 488 and 552 nm wavelengths. The measured linear depolarization ratios ranged from 0.03 to 0.36 and were strongly dependent on the particle size. The strongest size-dependence was observed for fine-mode particles as their depolarization ratios increased almost linearly with particle median diameter from 0.03 to 0.3, whereas the coarse-mode particle depolarization values stayed rather constant with a mean linear depolarization ratio of 0.27. The depolarization ratios were found to be insensitive to the dust source region or thin coating of the particles or to changes in relative humidity. We compared the measurements with results of three different scattering models. With certain assumptions for model particle shape, all the models were capable of correctly describing the size-dependence of the measured dust particle, albeit the model particles significantly differed in composition, shape and degree of complexity. Our results show potential for distinguishing the dust fine- and coarse-mode distributions based on their depolarization properties and, thus, can serve the lidar community as an empirical reference.

  11. Polarization-independent optical circulator for high accuracy Faraday depolarization lidar.

    PubMed

    Shiina, Tatsuo; Noguchi, Kazuo; Fukuchi, Tetsuo

    2012-03-01

    A high precision, polarization-independent optical circulator was developed for high accuracy Faraday depolarization lidar. Glan laser prisms and other novel optics were utilized in the circulator optics, resulting in a high extinction ratio of polarization of >30 dB. High accuracy is needed to detect a small rotation angle in the polarization plane of the propagating beam. It is generated by the Faraday effect due to the lightning discharge. The developed circulator delivered high performance of insertion loss and isolation as laser transmitter and echo receiver in the inline lidar optics. PMID:22410893

  12. 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. PMID:12833968

  13. Dielectric loss analysis using linear resonators with different impedances

    NASA Astrophysics Data System (ADS)

    Sarabi, Bahman; Khalil, M. S.; Khasawneh, M. A.; Stoutimore, M. J. A.; Gladchenko, Sergiy; Wellstood, F. C.; Lobb, C. J.; Osborn, K. D.

    2012-02-01

    It is known that amorphous dielectrics are a major source of decoherence in superconducting qubits due to energy absorption by two-level systems coupled to the electric fields. Linear resonators have been applied extensively to study loss in different dielectrics used in qubit circuits due to their versatility and relative simplicity in design, fabrication and measurement. We have designed linear resonators with multi-turn inductors and parallel-plate capacitors with resonance frequencies of 4.8-6.4 GHz. We achieve substantially different L/C values and capacitor volumes by varying the number of inductance turns and the area of the capacitors. We will present results of continuous wave measurements with SiNx capacitors and show how loss tangent and phase noise are related to impedance and capacitor volume.

  14. 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.

  15. Acousto-optic deflector of depolarized laser radiation

    NASA Astrophysics Data System (ADS)

    Antonov, S. N.

    2016-01-01

    An original acousto-optic deflector is based on the anisotropic diffraction in the paratellurite crystal. The deflector is characterized by a relatively high diffraction efficiency for depolarized laser radiation. The deflector consists of two sequential acousto-optic cells. Each cell deflects one of the orthogonally polarized components of the originally depolarized radiation. The first and second cells scan the low- and highfrequency parts of the angular interval, respectively. The simultaneous and independent operation of the cells makes it possible to use the entire optical (laser) power. A frequency band of 32 MHz is almost reached for depolarized radiation with a wavelength of 1.06 µm and the absolute angular interval is 50 mrad at a total efficiency of no less than 70%.

  16. Depolarization of subalfvenic plasma jet generating field-aligned currents

    NASA Astrophysics Data System (ADS)

    Sobyanin, D. B.; Gavrilov, B. G.; Podgorny, I. M.

    2004-01-01

    The subalfvenic magnetized plasma jet propagating across the geomagnetic field generates the field-aligned currents in ionospheric plasma. The transverse polarization electric field Ep = - V × B in the jet is reduced due to a leakage of polarization charges through the field-aligned currents (plasma jet depolarization). These phenomena are investigated in the laboratory experiment. It was revealed that the depolarization is accompanied by appearing of the electric field Ea along the plasma velocity vector and creation of an additional pair of the field-aligned currents being generated at the leading and trailing edge of the moving plasma. The value of Ea is comparable with the transverse electric field Ep. The depolarization results in the plasma jet deflection. The possibility of a manifestation of these effects in the NORTH STAR Russian-American active rocket experiment is discussed.

  17. 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.

  18. Depolarizing GABA acts on intrinsically bursting pyramidal neurons to drive giant depolarizing potentials in the immature hippocampus.

    PubMed

    Sipilä, Sampsa T; Huttu, Kristiina; Soltesz, Ivan; Voipio, Juha; Kaila, Kai

    2005-06-01

    Spontaneous periodic network events are a characteristic feature of developing neuronal networks, and they are thought to play a crucial role in the maturation of neuronal circuits. In the immature hippocampus, these types of events are seen in intracellular recordings as giant depolarizing potentials (GDPs) during the stage of neuronal development when GABA(A)-mediated transmission is depolarizing. However, the precise mechanism how GABAergic transmission promotes GDP occurrence is not known. Using whole-cell, cell-attached, perforated-patch, and field-potential recordings in hippocampal slices, we demonstrate here that CA3 pyramidal neurons in the newborn rat generate intrinsic bursts when depolarized. Furthermore, the characteristic rhythmicity of GDP generation is not based on a temporally patterned output of the GABAergic interneuronal network. However, GABAergic depolarization plays a key role in promoting voltage-dependent, intrinsic pyramidal bursting activity. The present data indicate that glutamatergic CA3 neurons have an instructive, pacemaker role in the generation of GDPs, whereas both synaptic and tonic depolarizing GABAergic mechanisms exert a temporally nonpatterned, facilitatory action in the generation of these network events. PMID:15930375

  19. 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. PMID:18251508

  20. 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

  1. Possible Depolarization Mechanism due to Low Beta Squeeze

    SciTech Connect

    Ranjbar,V.; Luccio, A.; Bai, M.

    2008-04-01

    Simulations reveal a potential depolarization mechanism during low beta squeeze. This depolarization appears to be driven by a spin tune modulation caused by spin precession through the strong low beta quads due to the vertical fields. The modulation of the spin tune introduces an additional snake resonance condition at {nu}{sub s0} {+-} n{nu}{sub x} - {nu}{sub z}l = integer which while the same numerology as the well known sextupole resonance, can operate in the absence of sextupole elements.

  2. Neutron depolarization study of phase transformations in steel

    NASA Astrophysics Data System (ADS)

    van Dijk, N. H.; Te Velthuis, S. G. E.; Rekveldt, M. Th.; Sietsma, J.; van der Zwaag, S.

    1999-06-01

    Three-dimensional neutron depolarization experiments have been performed in order to study the phase transformations from austenite (γ-Fe) into ferrite (α-Fe) and cementite (Fe 3C) in two medium-carbon steel samples with different carbon concentrations. The rotation of the neutron polarization vector during transmission through the sample is a direct measure for the ferromagnetic ferrite fraction. The degree of depolarization is related to the magnetic correlation length, which gives an indication of the characteristic length scales of the microstructure.

  3. 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.

  4. Comparative sensitivity analysis of transmission loss in beaked whale environments

    NASA Astrophysics Data System (ADS)

    Wezensky, Eryn M.; Miller, James H.; Tyce, Robert C.

    2001-05-01

    Scientific literature states that anthropogenic sound, such as mid-frequency sonar, may cause a behavioral response in marine mammals. The degree of response is highly variable and dependent upon many factors, including how sound transmission is influenced by environmental features. The physical parameters of the ocean medium, such as sound speed profile and bathymetry, are important controls of underwater acoustic propagation. Determining the acoustic propagation loss of the ocean environment is an application used to identify and correlate influential environmental factors. This study investigates the sensitivity of acoustic propagation loss based on specific physical characteristics found in five different sites representing beaked whale environments. These sites were chosen with regards to existing data on beaked whale distribution, historical mass stranding records, and presence of mid-frequency sonar activity. A range-independent, ray-tracing acoustic propagation model was used to generate a two-dimensional sound field over a range of 30 km. From the results of this experiment, the acoustic importance of bathymetry and sound speed profile of the five beaked whale environments were identified. Preliminary results from the experimental study will be presented.

  5. Comparative loss analysis and efficiency performance of resonance-based PDP sustain drivers

    NASA Astrophysics Data System (ADS)

    Kwak, S.-S.; Kim, I.-G.; Lee, J.

    2016-01-01

    Sustain drivers based on the LC resonant operation have a significant influence on the entire circuit efficiency and cost of plasma display panels (PDPs). Although circuit efficiency of PDP drivers is extremely important, theoretical loss analysis and comparative studies of the sustain drivers have been missed in the literature, despite a variety of developed PDP sustain drivers. This paper presents in detail theoretical analyses and systematic comparisons of semiconductor losses in the PDP sustain drivers, including the inevitable conduction losses by the displacement currents, the undesirable extra conduction losses, the switching losses by the forced current commutations and the switching losses by the step voltage changes. Based on derived theoretical analysis and comparative features, sustain drivers are evaluated in terms of PDP operating speed as well as circuits' efficiency.

  6. Landscape of the PARKIN-dependent ubiquitylome in response to mitochondrial depolarization

    PubMed Central

    Sarraf, Shireen A.; Raman, Malavika; Guarani-Pereira, Virginia; Sowa, Mathew E.; Huttlin, Edward L.; Gygi, Steven P.; Harper, J. Wade

    2013-01-01

    The PARKIN (PARK2) ubiquitin ligase and its regulatory kinase PINK1 (PARK6), often mutated in familial early onset Parkinson’s Disease (PD), play central roles in mitochondrial homeostasis and mitophagy.1–3 While PARKIN is recruited to the mitochondrial outer membrane (MOM) upon depolarization via PINK1 action and can ubiquitylate Porin, Mitofusin, and Miro proteins on the MOM,1,4–11 the full repertoire of PARKIN substrates – the PARKIN-dependent ubiquitylome - remains poorly defined. Here we employ quantitative diGLY capture proteomics12,13 to elucidate the ubiquitylation site-specificity and topology of PARKIN-dependent target modification in response to mitochondrial depolarization. Hundreds of dynamically regulated ubiquitylation sites in dozens of proteins were identified, with strong enrichment for MOM proteins, indicating that PARKIN dramatically alters the ubiquitylation status of the mitochondrial proteome. Using complementary interaction proteomics, we found depolarization-dependent PARKIN association with numerous MOM targets, autophagy receptors, and the proteasome. Mutation of PARKIN’s active site residue C431, which has been found mutated in PD patients, largely disrupts these associations. Structural and topological analysis revealed extensive conservation of PARKIN-dependent ubiquitylation sites on cytoplasmic domains in vertebrate and D. melanogaster MOM proteins. These studies provide a resource for understanding how the PINK1-PARKIN pathway re-sculpts the proteome to support mitochondrial homeostasis. PMID:23503661

  7. Quantitative and qualitative HPLC analysis of thermogenic weight loss products.

    PubMed

    Schaneberg, B T; Khan, I A

    2004-11-01

    An HPLC qualitative and quantitative method of seven analytes (caffeine, ephedrine, forskolin, icariin, pseudoephedrine, synephrine, and yohimbine) in thermogenic weight loss preparations available on the market is described in this paper. After 45 min the seven analytes were separated and detected in the acetonitrile: water (80:20) extract. The method uses a Waters XTerra RP18 (5 microm particle size) column as the stationary phase, a gradient mobile phase of water (5.0 mM SDS) and acetonitrile, and a UV detection of 210 nm. The correlation coefficients for the calibration curves and the recovery rates ranged from 0.994 to 0.999 and from 97.45% to 101.05%, respectively. The qualitative and quantitative results are discussed. PMID:15587578

  8. A New Analysis about Efficient Drive of Synchronous Reluctance Motors with Core Losses

    NASA Astrophysics Data System (ADS)

    Shinnaka, Shinji; Mukai, Taisuke

    This paper gives a new analysis for efficient drive of synchronous reluctance motors with core loss. The optimal current trajectory that minimizes totally copper and iron losses is newly and analytically derived. And it is shown that the optimal trajectory is a straight line tilting to q-axis with the speed.

  9. 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,…

  10. Depolarization Measurements with the High Spectral Resolution Lidar

    NASA Technical Reports Server (NTRS)

    Eloranta, E. W.; Piironen, P.

    1996-01-01

    This paper describes modifications to the University of Wisconsin High Spectral Resolution Lidar (HSRL) which permit very precise depolarization measurements in addition to optical depth, backscatter cross section, and extinction cross section measurements. Because HSRL separates the lidar return into aerosol and molecular contributions, they can be measured separately.

  11. Ca2+-Dependent Enhancement of Release by Subthreshold Somatic Depolarization

    PubMed Central

    Christie, Jason M.; Chiu, Delia N.; Jahr, Craig E.

    2010-01-01

    Summary In many neurons, subthreshold somatic depolarization can spread electrotonically into the axon and modulate subsequent spike-evoked transmission. Although release probability is regulated by intracellular Ca2+, the Ca2+-dependence of this modulatory mechanism has been debated. Using paired recordings from synaptically connected molecular-layer interneurons (MLIs) of the rat cerebellum, we observed Ca2+-mediated strengthening of release following brief subthreshold depolarization of the soma. Two-photon microscopy revealed that, at the axon, somatic depolarization evoked Ca2+ influx through voltage-sensitive Ca2+ channels (VSCCs) and facilitated spike-evoked Ca2+ entry. Exogenous Ca2+ buffering diminished these Ca2+ transients and eliminated the strengthening of release. Axonal Ca2+ entry elicited by subthreshold somatic depolarization also triggered asynchronous transmission that may deplete vesicle availability and thereby temper release strengthening. In this cerebellar circuit, activity-dependent presynaptic plasticity depends on Ca2+ elevations resulting from both sub- and suprathreshold electrical activity initiated at the soma. PMID:21170054

  12. Ice depolarization on low-angle 2 GHz satellite downlinks

    NASA Technical Reports Server (NTRS)

    Stutzman, W. L.; Bostian, C. W.; Tsolakis, A.; Pratt, T.

    1984-01-01

    The impact of ice depolarization on the statistical performance of satellite downlinks were investigated. Propagation data recorded during 1979 and 1980 to see what impact of ice depolarization on link performance were analyzed. The effects on the cross polarization discrimination (XPD) statistics amounted to at most a 2 to 4 dB reduction in the XPD values which rain would have produced for a given percentage of time. Ice depolarization had no effect on the statistics of XPD values below the 0.01% level. Most of the severe ice depolarization events were associated with drops in barometric pressure and the passage of intense cold fronts through our area. Ice contents as the product of three individually undetermined quantities were defined: ice particle density, ice cloud thickness, and the average volume of the ice crystals. It is indicated that populations of ice particle with ice contents on the order of 0.002 m4/m3 are probably responsible for the lower values of measured XPD.

  13. 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.

  14. 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. PMID:12396200

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  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. Atmospheric Depolarization Lidar Experimental Receiver: A Space Shuttle Hitchhiker Payload

    NASA Technical Reports Server (NTRS)

    McGill, Matthew J.; Scott, V. Stanley; Spinhirne, James D.

    1998-01-01

    Development work is underway at the Goddard Space Flight Center to construct a depolarization measuring atmospheric lidar receiver. The Atmospheric Lidar (AL) is tentatively scheduled to fly on the Space Shuttle in a late-1999 time frame. The AL will fly in conjunction with the Shuttle Laser Altimeter (SLA) and the Infrared Spectral Imaging Radiometer (ISIR) to provide a comprehensive package of atmospheric aerosol and cloud information. The AL operates in conjunction with the SLA laser transmitter and measures profiles of atmospheric backscatter at 532 nm. The receiver system discriminates between the parallel and perpendicular polarizations of the backscattered signal, thus providing depolarization ratios for scattering from clouds. The lidar receiver also provides cloud height and thickness measurements to complement the brightness temperature measurements generated by the ISIR thermal imager. The function of the AL is twofold. The primary function is to provide range-resolved measurements of atmospheric aerosol backscatter and depolarization ratio at 532 nm with 75 m vertical resolution. The scientific purpose of these measurements is to determine composition of clouds based on the depolarization ratio (i.e cloud content is water or ice), to determine cloud height and thickness, and to gain further understanding of the global distribution of aerosols. This information, when coupled with the cloud brightness measured by the ISIR thermal imager will provide a significant amount of information on cloud composition and radiative effects, particularly for cirrus and sub-visual cirrus clouds. A secondary function of the AL is to serve as an in-space test bed for lidar technology advancements, including a fully fiber-coupled receiver and photon counting from space. In addition, the data obtained by the AL will be used to develop software for the Geoscience Laser Altimeter System (GLAS) flight mission.

  3. 3D analysis of eddy current loss in the permanent magnet coupling

    NASA Astrophysics Data System (ADS)

    Zhu, Zina; Meng, Zhuo

    2016-07-01

    This paper first presents a 3D analytical model for analyzing the radial air-gap magnetic field between the inner and outer magnetic rotors of the permanent magnet couplings by using the Amperian current model. Based on the air-gap field analysis, the eddy current loss in the isolation cover is predicted according to the Maxwell's equations. A 3D finite element analysis model is constructed to analyze the magnetic field spatial distributions and vector eddy currents, and then the simulation results obtained are analyzed and compared with the analytical method. Finally, the current losses of two types of practical magnet couplings are measured in the experiment to compare with the theoretical results. It is concluded that the 3D analytical method of eddy current loss in the magnet coupling is viable and could be used for the eddy current loss prediction of magnet couplings.

  4. 3D analysis of eddy current loss in the permanent magnet coupling.

    PubMed

    Zhu, Zina; Meng, Zhuo

    2016-07-01

    This paper first presents a 3D analytical model for analyzing the radial air-gap magnetic field between the inner and outer magnetic rotors of the permanent magnet couplings by using the Amperian current model. Based on the air-gap field analysis, the eddy current loss in the isolation cover is predicted according to the Maxwell's equations. A 3D finite element analysis model is constructed to analyze the magnetic field spatial distributions and vector eddy currents, and then the simulation results obtained are analyzed and compared with the analytical method. Finally, the current losses of two types of practical magnet couplings are measured in the experiment to compare with the theoretical results. It is concluded that the 3D analytical method of eddy current loss in the magnet coupling is viable and could be used for the eddy current loss prediction of magnet couplings. PMID:27475575

  5. 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.

  6. 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

  7. Multiple scattering depolarization in marine stratus clouds: Lidar experiments

    NASA Technical Reports Server (NTRS)

    Sassen, K.; Petrilla, R. L.

    1986-01-01

    The depolarization of ruby lidar backscattering caused by multiple scattering in marine stratus clouds was examined systematically from a field site on the southern California coast. Investigated were the effects on the linear depolarization (delta) of lidar receiver field of view (FOV), elevation angle and laser beam pointing errors. An approximately linear increase in maximum delta values was observed with increasing receiver FOV, and the importance of accurate transmitter/receiver beam alignment was demonstrated during experiments in which the laser axis was deliberately misaligned. An elevation angle dependence to the delta values was observed as a consequence of the natural vertical inhomogeneity of water cloud content above the cloud base. Time histories of the depolarization characteristics of dissipating stratus clouds revealed significant spatial and temporal variability in delta values attributed to cloud composition variations. Employing a 1 mrad transmitter FOV, maximum delta values of 0.21 nd 0.33 were observed with 1 and 3 mrad receiver FOVs, respectively, from the low stratus clouds. The fundamental causes and effects on the lidar equation of multiple scattering are also discussed.

  8. 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.

  9. Spontaneous recovery from depolarizing drugs in rat diaphragm.

    PubMed Central

    Creese, R; Mitchell, L D

    1981-01-01

    1. The end-plate region in surface fibres of rat diaphragm was located by the use of polarizing filters. 2. Carbachol (100 microM) produced depolarization at the end-plate to -55 mV, as shown by continuous recording, with some indication of spontaneous recovery in the presence of the drug. The miniature end-plate potentials disappeared and remained absent. 3. By repeated sampling it was found that the resting potential at the end-plate had largely recovered after 45 min in the presence of carbachol. Individual fibres showed much variation in the rate of recovery, and in some fibres the repolarization was rapid. 4. In the absence of K, carbachol produced depolarization at the end-plate without significant recovery, as shown by repeated sampling. 5. When muscles were exposed to ouabain (100 microM) in addition to carbachol the end-plate remained depolarized without recovery for 60 min. The effect of ouabain was reversible: withdrawal of ouabain (in the presence of carbachol) led to substantial recovery. 6. Suberyldicholine (100 microM) gave results which were similar to those produced by carbachol. 7. It was inferred that the spontaneous recovery of membrane potential in the presence of carbachol and of suberyldicholine is a process which is sensitive to K and to ouabain. Images Plate 1 PMID:7277216

  10. 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

  11. Analysis of eddy current losses during discharging period in a 600 kJ SMES

    NASA Astrophysics Data System (ADS)

    Park, M. J.; Kwak, S. Y.; Lee, S. Y.; Kim, W. S.; Lee, J. K.; Park, C.; Choi, K.; Bae, J. H.; Kim, S. H.; Sim, K. D.; Seong, K. C.; Jung, H. K.; Hahn, S.

    2008-09-01

    The operation of the SMES system can be divided into three modes such as charging, operating and discharging. During the charging and the discharging modes, a magnetic field variation due to the current increase and decrease generate eddy current losses in the SMES system. The eddy current loss in discharging mode is the major factor to be considered because the operating time in the mode is fixed, whereas the charging mode has the arbitrary operating time which is not fixed. In this paper, we present the analysis results of the eddy current losses which are generated in the 600 kJ class HTS SMES system during the discharging mode.

  12. 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

  13. 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. PMID:22472758

  14. 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.

  15. Tooth Loss and Head and Neck Cancer: A Meta-Analysis of Observational Studies

    PubMed Central

    Zeng, Xian-Tao; Luo, Wei; Huang, Wei; Wang, Quan; Guo, Yi; Leng, Wei-Dong

    2013-01-01

    Backgroud Epidemiological studies have shown that tooth loss is associated with risk of head and neck cancer (HNC); however, the results were inconsistent. Therefore, we conducted a meta-analysis to ascertain the relationship between tooth loss and HNC. Methods We searched for relevant observational studies that tested the association between tooth loss and risk of HNC from PubMed and were conducted up to January 30, 2013. Data from the eligible studies were independently extracted by two authors. The meta-analysis was performed using the Comprehensive Meta-Analysis 2.2 software. Sensitivity and subgroup analyses were conducted to evaluate the influence of various inclusions. Publication bias was also detected. Results Ten articles involving one cohort and ten case-control studies were yielded. Based on random-effects meta-analysis, an association between tooth loss and HNC risk was identified [increased risk of 29% for 1 to 6 teeth loss (OR = 1.29, 95% CI = 0.52–3.20, p = 0.59), 58% for 6 to 15 teeth loss (OR = 1.58, 95% CI = 1.08–2.32, p = 0.02), 63% for 11+ teeth loss (OR = 1.63, 95% CI = 1.23–2.14, p<0.001), 72% for 15+ teeth loss (OR = 1.72, 95% CI = 1.26–2.36, p<0.001), and 89% for 20+ teeth loss (OR = 1.89, 95% CI = 1.27–2.80, p<0.001)]. The sensitivity analysis shows that the result was robust, and publication bias was not detected. Conclusions Based on the current evidence, tooth loss is probably a significant and dependent risk factor of HNC, which may have a dose-response effect. People who lost six or more teeth should pay attention to symptoms of HNC, and losing 11 teeth or 15 teeth may be the threshold. PMID:24260154

  16. 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.

  17. Fission product transport analysis in a loss of decay heat removal accident at Browns Ferry

    SciTech Connect

    Wichner, R.P.; Weber, C.F.; Hodge, S.A.; Beahm, E.C.; Wright, A.L.

    1984-01-01

    This paper summarizes an analysis of the movement of noble gases, iodine, and cesium fission products within the Mark-I containment BWR reactor system represented by Browns Ferry Unit 1 during a postulated accident sequence initiated by a loss of decay heat removal (DHR) capability following a scram. The event analysis showed that this accident could be brought under control by various means, but the sequence with no operator action ultimately leads to containment (drywell) failure followed by loss of water from the reactor vessel, core degradation due to overheating, and reactor vessel failure with attendant movement of core debris onto the drywell floor.

  18. 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

  19. An alternative video footprint analysis to assess functional loss following injury to the rat sciatic nerve.

    PubMed

    Bervar, M

    2002-01-01

    The rat sciatic nerve is a well-established animal model for the study of recovery from peripheral nerve injuries. Footprint analysis is the most widely used non-invasive method of measuring functional recovery after injury in this model. We describe a new, alternative video analysis of standing (or static footprint video analysis) to assess functional loss following injury to the rat sciatic nerve, while the animal is standing or at periodic rest on a flat transparent surface. We found that this alternative video analysis is technically easier to perform than the corresponding footprint video analysis while walking, but still preserves all advantages of video versus conventional ink track method: i.e. few non-measurable footprints, better repeatability, high accuracy and more precise quantification of the degree of functional loss after sciatic nerve injury in the rat. PMID:12514995

  20. 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

  1. Kisspeptin depolarizes gonadotropin-releasing hormone neurons through activation of TRPC-like cationic channels.

    PubMed

    Zhang, Chunguang; Roepke, Troy A; Kelly, Martin J; Rønnekleiv, Oline K

    2008-04-23

    Kisspeptin and its cognate receptor, GPR54, are critical for reproductive development and for the regulation of gonadotropin-releasing hormone (GnRH) secretion. Although kisspeptin has been found to depolarize GnRH neurons, the underlying ionic mechanism has not been elucidated. Presently, we found that kisspeptin depolarized GnRH neurons in a concentration-dependent manner with a maximum depolarization of 22.6 +/- 0.6 mV and EC(50) of 2.8 +/- 0.2 nM. Under voltage-clamp conditions, kisspeptin induced an inward current of 18.2 +/- 1.6 pA (V(hold) = -60 mV) that reversed near -115 mV in GnRH neurons. The more negative reversal potential than E(K)(+) (-90 mV) was caused by the concurrent inhibition of barium-sensitive, inwardly rectifying (Kir) potassium channels and activation of sodium-dependent, nonselective cationic channels (NSCCs). Indeed, reducing extracellular Na(+) (to 5 mM) essentially eliminated the kisspeptin-induced inward current. The current-voltage relationships of the kisspeptin-activated NSCC currents exhibited double rectification with negative slope conductance below -40 mV in the majority of the cells. Pharmacological examination showed that the kisspeptin-induced inward currents were blocked by TRPC (canonical transient receptor potential) channel blockers 2-APB (2-aminoethyl diphenylborinate), flufenamic acid, SKF96365 (1-[beta-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenethyl]-1H-imidazole hydrochloride), and Cd(2+), but not by lanthanum (100 microM). Furthermore, single-cell reverse transcription-PCR analysis revealed that TRPC1, TRPC3, TRPC4, TRPC5, TRPC6, and TRPC7 subunits were expressed in GnRH neurons. Therefore, it appears that kisspeptin depolarizes GnRH neurons through activating TRPC-like channels and, to a lesser extent, inhibition of Kir channels. These actions of kisspeptin contribute to the pronounced excitation of GnRH neurons that is critical for mammalian reproduction. PMID:18434521

  2. Coupling loss factor of linear vibration energy harvesting systems in a framework of statistical energy analysis

    NASA Astrophysics Data System (ADS)

    Wang, Xu

    2016-02-01

    This paper establishes coupling loss factor of linear vibration energy harvesting systems in a framework of statistical energy analysis under parameter variations and random excitations. The new contributions of this paper are to define the numerical ranges of the dimensionless force factor for the weak, moderate and strong coupling and to study the connections of dimensionless force factor, coupling loss factor, coupling quotient, critical coupling strength, electro-mechanical coupling factor, damping loss factor and modal densities in linear vibration energy harvesting systems. The motivation of this paper is to enable statistical energy analysis of linear vibration energy harvesting systems for reliable performance predictions and design optimisation under parameter variations of materials and manufacturing processes and random ambient environmental excitations.

  3. 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. PMID:26162812

  4. CATALYST EVALUATION FOR A SULFUR DIOXIDE-DEPOLARIZED ELECTROLYZER

    SciTech Connect

    Hobbs, D; Hector Colon-Mercado, H

    2007-01-31

    Thermochemical processes are being developed to provide global-scale quantities of hydrogen. A variant on sulfur-based thermochemical cycles is the Hybrid Sulfur (HyS) Process which uses a sulfur dioxide depolarized electrolyzer (SDE) to produce the hydrogen. Testing examined the activity and stability of platinum and palladium as the electrocatalyst for the SDE in sulfuric acid solutions. Cyclic and linear sweep voltammetry revealed that platinum provided better catalytic activity with much lower potentials and higher currents than palladium. Testing also showed that the catalyst activity is strongly influenced by the concentration of the sulfuric acid electrolyte.

  5. Confocal zero-angle dynamic depolarized light scattering.

    PubMed

    Potenza, M A C; Sanvito, T; Alaimo, M D; Degiorgio, V; Giglio, M

    2010-01-01

    We present a novel Dynamic Depolarized Scattering method based on a tight confocal, zero scattering angle, heterodyne scheme. The method is highly immune from parasitic multiple-scattering contributions, so that it can operate with non-index-matched samples presenting large turbidity. It provides measurements of both rotational and translational diffusion coefficients, the latter via number fluctuation spectroscopy. In addition, the amplitude ratio between the two baselines for the fast rotational mode and the slow translational mode can be used to determine the particles intrinsic birefringence. PMID:20087622

  6. 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

  7. 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. PMID:26550930

  8. 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%).

  9. 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)

  10. 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

  11. Geometrical analysis of the loss of ablation efficiency at non-normal incidence.

    PubMed

    Arba-Mosquera, Samuel; de Ortueta, Diego

    2008-03-17

    A general method to analyze the loss of ablation efficiency at non-normal incidence in a geometrical way is provided. The model is comprehensive and directly considers curvature, system geometry, applied correction, and astigmatism as model parameters, and indirectly laser beam characteristics and ablative spot properties. The model replaces the direct dependency on the fluence by a direct dependence on the nominal spot volume and on considerations about the area illuminated by the beam, reducing the analysis to pure geometry of impact. Compensation of the loss of ablation efficiency at non-normal incidence can be made at relatively low cost and would directly improve the quality of results. PMID:18542485

  12. Partially coherent electromagnetic beams propagating through double-wedge depolarizers

    NASA Astrophysics Data System (ADS)

    de Sande, J. Carlos G.; Piquero, Gemma; Santarsiero, Massimo; Gori, Franco

    2014-03-01

    The irradiance and polarization characteristics of quasi-monochromatic partially coherent electromagnetic beams are analyzed when they propagate after passing through a deterministic linear optical element, i.e., an optical element that can be represented by a Jones matrix. A class of such optical elements, which includes double-wedge depolarizers and polarization gratings, is defined and studied in detail. Analytical expressions are obtained for the case of double-wedge depolarizers and examples are given for an incident Gaussian Schell-model beam. For such an input beam, the effects on the irradiance and degree of polarization of the field propagating beyond the optical element are investigated in detail. A rich variety of behaviors is obtained by varying the beam size, coherence width and polarization state of the input field. The results not only provide a mathematical extension of well-known results to the domain of partial coherence, but they also exemplify mixing between coherence and polarization, which is, of course, not possible if, for example, fully spatially coherent fields are analyzed.

  13. Widespread depolarization during expiration: a source of respiratory drive?

    PubMed

    Jerath, Ravinder; Crawford, Molly W; Barnes, Vernon A; Harden, Kyler

    2015-01-01

    Respiration influences various pacemakers and rhythms of the body during inspiration and expiration but the underlying mechanisms are relatively unknown. Understanding this phenomenon is important, as breathing disorders, breath holding, and hyperventilation can lead to significant medical conditions. We discuss the physiological modulation of heart rhythm, blood pressure, sympathetic nerve activity, EEG, and other changes observed during inspiration and expiration. We also correlate the intracellular mitochondrial respiratory metabolic processes with real-time breathing and correlate membrane potential changes with inspiration and expiration. We propose that widespread minor hyperpolarization occurs during inspiration and widespread minor depolarization occurs during expiration. This depolarization is likely a source of respiratory drive. Further knowledge of intracellular and extracellular ionic changes associated with respiration will enhance ourunderstanding of respiration and its role as a modulator of cellular membrane potential. This could expand treatment options for a wide range of health conditions, such as breathing disorders, stress-related disorders, and further our understanding of the Hering-Breuer reflex and respiratory sinus arrhythmia. PMID:25434482

  14. 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

  15. 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.

  16. Thermoreversible Changes in Aligned and Cross-Linked Block Copolymer Melts Studied by Two Color Depolarized Light Scattering

    SciTech Connect

    Wilbur, Jeffrey D.; Gomez, Enrique D.; Ellsworth, Mark W.; Garetz, Bruce A.; Balsara, Nitash P.

    2012-09-04

    A procedure for creating samples that can be repeatedly cycled between weakly aligned and strongly aligned states is described. Poly(styrene-b-isoprene) block copolymer samples were first shear-aligned and then cross-linked using a high energy electron beam. Samples with more than 1.0 cross-links per chain on average showed almost complete recovery of their initial alignment state even after 20 cycles of heating above the order–disorder transition temperature of the un-cross-linked block copolymer. Samples with 1.1 cross-links per chain, which showed over 90% loss of alignment on heating and almost 100% recovery of alignment on cooling, provided the best example of a reversible aligned-to-unaligned transition. Samples with lower cross-linking densities exhibited irreversible loss of alignment upon heating, while those with higher cross-linking densities exhibited less than 90% loss of alignment upon heating. Alignment was quantified by a technique that we call two color depolarized light scattering (TCDLS), an extension of the traditional depolarized light scattering experiment used to determine the state of order in block copolymers. Qualitative confirmation of our interpretation of TCDLS data was obtained by small-angle X-ray scattering and transmission electron microscopy.

  17. Stability analysis, non-linear pulsations and mass loss of models for 55 Cygni (HD 198478)

    NASA Astrophysics Data System (ADS)

    Yadav, Abhay Pratap; Glatzel, Wolfgang

    2016-04-01

    55 Cygni is a variable supergiant. Recent observational studies revealed that this star pulsates in pressure, gravity and strange modes. The pulsations seem to be associated with episodes of mass loss. In this paper we present a theoretical study of stellar models with parameters close to that of 55 Cygni. A linear non-adiabatic stability analysis with respect to radial perturbations is performed and the evolution of instabilities into the non-linear regime is followed by numerical simulation. Our study indicates that the mass of 55 Cygni lies below 28 M⊙. As the final consequence of the instabilities the non-linear simulations revealed finite amplitude pulsations with periods consistent with the observations. The non-linear results also indicate a connection between pulsations and mass loss and allow for an estimate of the mean mass-loss rate. It is consistent with the observed values.

  18. 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.

  19. 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

  20. 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

  1. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

    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 V H ( 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 Q2. 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.

  3. 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. PMID:26233160

  4. [Intramural chronotopography of depolarization of myocardium of heart ventricles of pig (Sus scrofa domesticus)].

    PubMed

    2014-01-01

    Sequence of depolarization of myocardium of pig heart ventricles was studied by the method of multichannel synchronous cardioelectrotopography. There is established formation of areas of early depolarization in subendocardium of interventricular septum and in the base of left ventricle papillary muscles; of multiple foci--in the depth of walls; of areas of late depolarization--in subepicardium of the left ventricle dorsolateral side. As compared with other species of ungulate animals (reindeer and sheep, in pig heart ventricles, differences are revealed in locations of early and late depolarization, a breakdown of the excitation wave into subepicardium. PMID:25508945

  5. [Intramural chronotopography of depolarization of myocardium of heart ventricles of pig (Sus scrofa domesticus)].

    PubMed

    Gulyaeva, A S; Roshchecskaya, I M; Roshchevsky, M P

    2014-01-01

    Sequence of depolarization of myocardium of pig heart ventricles was studied by the method of multichannel synchronous cardioelectrotopography. There is established formation of areas of early depolarization in subendocardium of interventricular septum and in the base of left ventricle papillary muscles; of multiple foci--in the depth of walls; of areas of late depolarization--in subepicardium of the left ventricle dorsolateral side. As compared with other species of ungulate animals (reindeer and sheep, in pig heart ventricles, differences are revealed in locations of early and late depolarization, a breakdown of the excitation wave into subepicardium. PMID:25486814

  6. 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

  7. 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.

  8. Analysis of depressurized loss-of-forced cooling transients by HERA

    SciTech Connect

    Rider, W.J.; Cappiello, M.W.

    1991-01-01

    The Modular High-Temperature Gas-Cooled Reactor (MHTGR) is one of the next generation reactors, which has passive safety features. Among these safety features is the ability to withstand a depressurized, loss-of-forced cooling of the reactor without release of fission products from the primary containment. In order to assess the capability of the MHTGR to withstand this type of accident condition, the thermal behavior of the reactor core must be well understood. To accomplish this, we have employed the HElium cooled Reactor Analysis code (HERA) to study the MHTGR under these conditions. Our analysis will demonstrate that the MHTGR is capable of withstanding a depressurized loss-of-forced cooling, even under worst case circumstances. 7 refs., 14 figs., 5 tabs.

  9. Individual loss distribution measurement in 32-branched PON using pulsed pump-probe Brillouin analysis.

    PubMed

    Takahashi, Hiroshi; Ito, Fumihiko; Kito, Chihiro; Toge, Kunihiro

    2013-03-25

    We describe loss distribution measurement in a passive optical network (PON) using pulsed pump-probe Brillouin analysis. A preliminary experiment is demonstrated using a 32-branched PON constructed in the laboratory. We analyze the signal to noise ratio of this measurement and show that the method can realize a 25 dB dynamic range in 90 seconds (10000 times averaging), with an event location resolution of 10 m, and a fiber length identification resolution of 2 m. PMID:23546056

  10. Loss Modeling with a Data-Driven Approach in Event-Based Rainfall-Runoff Analysis

    NASA Astrophysics Data System (ADS)

    Chua, L. H. C.

    2012-04-01

    is completely impervious and the losses are small. Thus, the good agreement of results between the ANN with the KW model results demonstrates the applicability of the ANN model in modeling the loss rate. Comparing the modeled runoff with the measured runoff for the Upper Bukit Timah catchment, it was found that the KW model was not able to produce the runoff from the catchment accurately due to the improper prescription of the loss rate. This is because the loss rate varies over a wide range of values in a real catchment and using the loss rate for an average event did not provide truly representative values for the catchment. Although the same dataset was used in the training of the ANN model, the ANN model was able to produce hydrographs with significantly higher Nash-Sutcliffe coefficients compared to the KW model. This analysis demonstrates that the ANN model is better able to model the highly variable loss rate during storm events, especially if the data used for calibration is limited. ACKNOWLEDGEMENT Funding received from the DHI-NTU Water & Environment Research Centre and Education Hub is gratefully acknowledged.

  11. Rayleigh scattering and depolarization ratio in linear alkylbenzene

    NASA Astrophysics Data System (ADS)

    Liu, Qian; Zhou, Xiang; Huang, Wenqian; Zhang, Yuning; Wu, Wenjie; Luo, Wentai; Yu, Miao; Zheng, Yangheng; Zhou, Li; Cao, Jun; Wang, Yifang

    2015-09-01

    It is planned to use linear alkylbenzene (LAB) as the organic solvent for the Jiangmen Underground Neutrino Observatory (JUNO) liquid scintillator detectors, due to its ultra-transparency. However, the current Rayleigh scattering length calculation for LAB disagrees with the experimental measurement. This paper reports for the first time that the Rayleigh scattering of LAB is anisotropic, with a depolarization ratio of 0.31±0.01(stat.)±0.01(sys.). We use an indirect method for Rayleigh scattering measurement with the Einstein-Smoluchowski-Cabannes formula, and the Rayleigh scattering length of LAB is determined to be 28.2±1.0 m at 430 nm.

  12. 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.

  13. Depolarization of decaying counterflow turbulence in He II.

    PubMed

    Barenghi, C F; Gordeev, A V; Skrbek, L

    2006-08-01

    We present experimental evidence backed up by numerical simulations that the steady-state vortex tangle created in He II by heat-transfer counterflow is strongly polarized. When the heater that generates the counterflow turbulence is switched off, the vortex tangle decays, the vortex lines randomize their spatial orientation and the tangle's polarization decreases. The process of depolarization slows down the recovery of the transverse second sound signal which measures the vortex line density; at some values of parameters it even leads to a net decrease of the amplitude of the transverse second sound prior to reaching the universal -32 power temporal law decay typical of classical homogeneous isotropic turbulence in a finite-sized channel. PMID:17025541

  14. Depolarization of decaying counterflow turbulence in He II

    SciTech Connect

    Barenghi, C. F.; Gordeev, A. V.; Skrbek, L.

    2006-08-15

    We present experimental evidence backed up by numerical simulations that the steady-state vortex tangle created in He II by heat-transfer counterflow is strongly polarized. When the heater that generates the counterflow turbulence is switched off, the vortex tangle decays, the vortex lines randomize their spatial orientation and the tangle's polarization decreases. The process of depolarization slows down the recovery of the transverse second sound signal which measures the vortex line density; at some values of parameters it even leads to a net decrease of the amplitude of the transverse second sound prior to reaching the universal -3/2 power temporal law decay typical of classical homogeneous isotropic turbulence in a finite-sized channel.

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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

  20. Effect of obesity and weight loss on ventricular repolarization: a systematic review and meta-analysis.

    PubMed

    Omran, J; Firwana, B; Koerber, S; Bostick, B; Alpert, M A

    2016-06-01

    We performed a systematic review and meta-analysis of the effects of obesity ± overweight and weight loss on the corrected QT interval (QTc) and QT or QTc dispersion (indices of ventricular repolarization). Mean difference for both QTc and QT or QTc dispersion with 95% confidence intervals (CIs) was calculated comparing obese ± overweight subjects and normal weight controls and QTc and QT or QTc dispersion before and after weight loss from diet ± exercise or bariatric surgery. A total of 22 studies fulfilled the selection criteria. Compared with normal weight controls, there was a significantly longer QTc in obese ± overweight subjects (mean difference of 21.74 msec, 95% CI: 18.76 to 22.32) and significantly longer QT or QTc dispersion (mean difference of 15.17 msec, 95% CI: 13.59 to 16.74). Weight loss was associated with a significant decrease in QTc (mean difference -25.77 msec, 95% CI: -28.33-23.21) and QT or QTc dispersion (mean difference of -13.46 msec, 95% CI: -15.60 to -11.32 in obese ± overweight subjects. Thus, obesity ± overweight is associated with significant prolongation of QTc and QT or QTC dispersion. Weight loss in obese ± overweight subjects produces significant decreases in these variables. © 2016 World Obesity. PMID:26956255

  1. Analysis of Loss Mechanisms in G-M Type Pulse Tube Refrigerators

    NASA Astrophysics Data System (ADS)

    Baik, J. H.; Nellis, G. F.; Pfotenhauer, J. M.

    2004-06-01

    A one dimensional, numerical analysis that considers the heat transfer between the pulse tube walls and the internal working fluid has been performed to incorporate DC flow and shuttle heat loss mechanisms in a 5-valve G-M type pulse tube refrigerator model. All of the physical dimensions and operating conditions associated with three refrigeration systems built at UW-Madison have been used to provide input information for a 1st and 2nd order numerical analysis. The 1st order numerical analysis assumes that the pulse-tube is adiabatic and predicts the pressure, temperatures and mass flow rates at any time and location during a cycle. The gas and wall temperature profiles are subsequently modified by a 2nd order analysis that considers more realistic thermal behavior in the pulse-tube by explicitly modeling the heat transfer interaction between the fluid and the wall. Three different convective heat transfer correlations have been considered. The 2nd order analysis allows the calculation of various losses including DC flow and shuttle heat transfer in order to predict actual performances of the systems. The comparisons of the numerical model with a series of experimental results display very good agreement across significantly different system geometries and operating conditions.

  2. Analysis of loss-of-coolant and loss-of-flow accidents in the first wall cooling system of NET/ITER

    NASA Astrophysics Data System (ADS)

    Komen, E. M. J.; Koning, H.

    1994-03-01

    This paper presents the thermal-hydraulic analysis of potential accidents in the first wall cooling system of the Next European Torus or the International Thermonuclear Experimental Reactor. Three ex-vessel loss-of-coolant accidents, two in-vessel loss-of-coolant accidents, and three loss-of-flow accidents have been analyzed using the thermal-hydraulic system analysis code RELAP5/MOD3. The analyses deal with the transient thermal-hydraulic behavior inside the cooling systems and the temperature development inside the nuclear components during these accidents. The analysis of the different accident scenarios has been performed without operation of emergency cooling systems. The results of the analyses indicate that a loss of forced coolant flow through the first wall rapidly causes dryout in the first wall cooling pipes. Following dryout, melting in the first wall starts within about 130 s in case of ongoing plasma burning. In case of large break LOCAs and ongoing plasma burning, melting in the first wall starts about 90 s after accident initiation.

  3. 3-D Magnetic Field Analysis of Permanent Magnet Motor Considering Magnetizing, Demagnetizing and Eddy Current Loss

    NASA Astrophysics Data System (ADS)

    Miyata, Koji; Aoyama, Yasuaki; Yokoyama, Tomonori; Ohashi, Ken; Kondo, Minoru; Matsuoka, Koichi

    Rare-earth magnets, which have high energy product, have been widely used in several industrial applications such as voice coil motors for hard disk drives, MRI for medical devices and motors for electric vehicle. In order to realize a small and high performance device, the magnetic field analysis techniques are required. In this paper, we applied the magnetic field analysis to design the permanent magnet synchronous motors into the rail traction system. In the inverter fed motor drive, the eddy current loss in the permanent magnet increased. We simulated the effect that eddy current was decreased by using a divided permanent magnet. Furthermore, the permanent magnet tends to be demagnetized due to the effect of a demagnetizing field formed at high temperatures. However, according to our analysis, demagnetization does not occur within the range of our design specifications. Also, we performed magnetic field analysis assuming a pulse-type magnetization process and designed an optimal magnetizing coil.

  4. On Depolarization Lidar-Based Method for The Determination of Liquid-Cloud Microphysical Properties

    NASA Astrophysics Data System (ADS)

    Roy, Gilles; Cao, Xiaoying; Tremblay, Grégoire; Bernier, Robert

    2016-06-01

    Under single scattering conditions, water droplets clouds do not depolarize the backscattered light. However, backscattered light from multiple scattering will be depolarized. The level of depolarization is a function of the droplets size, the cloud extinction coefficient value and profile; it has also an important dependency on the lidar field-of-view (FOV). The use of depolarization information to retrieve cloud microphysical properties, using Multiple-FOV has been the object of studies, [1], [2]. Recently the use of the depolarization, at a single FOV, has been studied for cloud with linear liquid water content profiles, [3], [4]. In this paper we present the mechanism leading to depolarization and identify the FOV values for which the information on particle size is high. Also Monte Carlo simulations for cloud with constant and ramp up profiles are presented. The degree of linear depolarization as a function of cloud penetration is significantly different for both cloud profiles. This suggests that the use of the degree of linear depolarization at a single FOV should be used with caution to determine clouds micro-physical parameters.

  5. Psychological and behavioral consequences of job loss: a covariance structure analysis using Weiner's (1985) attribution model.

    PubMed

    Prussia, G E; Kinicki, A J; Bracker, J S

    1993-06-01

    B. Weiner's (1985) attribution model of achievement motivation and emotion was used as a theoretical foundation to examine the mediating processes between involuntary job loss and employment status. Seventy-nine manufacturing employees were surveyed 1 month prior to permanent displacement, and finding another job was assessed 18 months later. Covariance structure analysis was used to evaluate goodness of fit and to compare the model to alternative measurement and structural representations. Discriminant validity analyses indicated that the causal dimensions underlying the model were not independent. Model predictions were supported in that internal and stable attributions for job loss negatively influenced finding another job through expectations for re-employment. These predictions held up even after controlling for influential unmeasured variables. Practical and theoretical implications are discussed. PMID:8331023

  6. Improved method for minimizing sulfur loss in analysis of particulate organic sulfur.

    PubMed

    Park, Ki-Tae; Lee, Kitack; Shin, Kyoungsoon; Jeong, Hae Jin; Kim, Kwang Young

    2014-02-01

    The global sulfur cycle depends primarily on the metabolism of marine microorganisms, which release sulfur gas into the atmosphere and thus affect the redistribution of sulfur globally as well as the earth's climate system. To better quantify sulfur release from the ocean, analysis of the production and distribution of organic sulfur in the ocean is necessary. This report describes a wet-based method for accurate analysis of particulate organic sulfur (POS) in the marine environment. The proposed method overcomes the considerable loss of sulfur (up to 80%) that occurs during analysis using conventional methods involving drying. Use of the wet-based POS extraction procedure in conjunction with a sensitive sulfur analyzer enabled accurate measurements of cellular POS. Data obtained using this method will enable accurate assessment of how rapidly sulfur can transfer among pools. Such information will improve understanding of the role of POS in the oceanic sulfur cycle. PMID:24428718

  7. Adenosine receptor activation is responsible for prolonged depression of synaptic transmission after spreading depolarization in brain slices.

    PubMed

    Lindquist, B E; Shuttleworth, C W

    2012-10-25

    Spreading depolarization (SD) is a slowly propagating, coordinated depolarization of brain tissue, which is followed by a transient (5-10min) depression of synaptic activity. The mechanisms for synaptic depression after SD are incompletely understood. We examined the relative contributions of action potential failure and adenosine receptor activation to the suppression of evoked synaptic activity in murine brain slices. Focal micro-injection of potassium chloride (KCl) was used to induce SD and synaptic potentials were evoked by electrical stimulation of Schaffer collateral inputs to hippocampal area Cornu Ammonis area 1 (CA1). SD was accompanied by loss of both presynaptic action potentials (as assessed from fiber volleys) and field excitatory postsynaptic potentials (fEPSPs). Fiber volleys recovered rapidly upon neutralization of the extracellular direct current (DC) potential, whereas fEPSPs underwent a secondary suppression phase lasting several minutes. Paired-pulse ratio was elevated during the secondary suppression period, consistent with a presynaptic mechanism of synaptic depression. A transient increase in extracellular adenosine concentration was detected during the period of secondary suppression. Antagonists of adenosine A1 receptors (8-cyclopentyl-1,3-dipropylxanthine [DPCPX] or 8-cyclopentyl-1,3-dimethylxanthine [8-CPT]) greatly accelerated fEPSP recovery and abolished increases in paired-pulse ratio normally observed after SD. The duration of fEPSP suppression was correlated with both the duration of the DC shift and the area of tissue depolarized, consistent with the model that adenosine accumulates in proportion to the metabolic burden of SD. These results suggest that in brain slices, the duration of the DC shift approximately defined the period of action potential failure, but the secondary depression of evoked responses was in large part due to endogenous adenosine accumulation after SD. PMID:22864185

  8. Phenome Analysis in Plant Species Using Loss-of-Function and Gain-of-Function Mutants

    PubMed Central

    Kuromori, Takashi; Takahashi, Shinya; Kondou, Youichi; Shinozaki, Kazuo; Matsui, Minami

    2009-01-01

    Analysis of genetic mutations is one of the most effective ways to investigate gene function. We now have methods that allow for mass production of mutant lines and cells in a variety of model species. Recently, large numbers of mutant lines have been generated by both ‘loss-of-function’ and ‘gain-of-function’ techniques. In parallel, phenotypic information covering various mutant resources has been acquired and released in web-based databases. As a result, significant progress in comprehensive pheno-type analysis is being made through the use of these tools. Arabidopsis and rice are two major model plant species in which genome sequencing projects have been completed. Arabidopsis is the most widely used experimental plant, with a large number of mutant resources and several examples of systematic phenotype analysis. Rice is a major crop species and is used as a model plant, with an increasing number of mutant resources. Other plant species are also being employed in functional genetics research. In this review, the present status of mutant resources for large-scale studies of gene function in plant research and the current perspective on using loss-of-function and gain-of-function mutants in phenome research will be discussed. PMID:19502383

  9. Analysis of catalytic gas products using electron energy-loss spectroscopy and residual gas analysis for operando transmission electron microscopy.

    PubMed

    Miller, Benjamin K; Crozier, Peter A

    2014-06-01

    Operando transmission electron microscopy (TEM) of catalytic reactions requires that the gas composition inside the TEM be known during the in situ reaction. Two techniques for measuring gas composition inside the environmental TEM are described and compared here. First, electron energy-loss spectroscopy, both in the low-loss and core-loss regions of the spectrum was utilized. The data were quantified using a linear combination of reference spectra from individual gasses to fit a mixture spectrum. Mass spectrometry using a residual gas analyzer was also used to quantify the gas inside the environmental cell. Both electron energy-loss spectroscopy and residual gas analysis were applied simultaneously to a known 50/50 mixture of CO and CO2, so the results from the two techniques could be compared and evaluated. An operando TEM experiment was performed using a Ru catalyst supported on silica spheres and loaded into the TEM on a specially developed porous pellet TEM sample. Both techniques were used to monitor the conversion of CO to CO2 over the catalyst, while simultaneous atomic resolution imaging of the catalyst was performed. PMID:24815065

  10. 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.

  11. Weight loss interventions for morbidly obese patients with compensated cirrhosis: a Markov decision analysis model.

    PubMed

    Bromberger, Bianca; Porrett, Paige; Choudhury, Rashikh; Dumon, Kristoffel; Murayama, Kenric M

    2014-02-01

    Many transplant centers require that patients maintain a BMI below 40 kg/m(2) in order to be eligible for listing, rendering many morbidly obese patients with end-stage liver disease unable to access liver transplantation as a method of treatment. In order to determine the safest and most efficacious weight loss regimen in this challenging population, Roux-en-Y gastric bypass (RYGB), adjustable gastric banding (AGB), and diet and exercise were modeled to assess their impact on life expectancy in morbidly obese patients with cirrhosis. A Markov state transition model was developed to assess the survival benefit of undergoing RYGB, AGB, or 1 year of diet and exercise in morbidly obese patients with compensated cirrhosis. A base case analysis of no weight loss intervention in a 45-year-old patient with compensated cirrhosis and a BMI of 45 kg/m(2) revealed an average survival of 7.93 years. The average survival for the weight loss simulations was 9.14, 8.84, and 8.16 years for RYGB, AGB, and diet and exercise, respectively. In morbidly obese patients with compensated cirrhosis, RYGB allows patients to lose more weight more rapidly than is probable with either AGB or diet and exercise, thus having the greatest impact on survival. PMID:23918085

  12. 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. PMID:19541318

  13. 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.

  14. 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

  15. 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.

  16. 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,…

  17. 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.

  18. 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.

  19. Effect of depolarization on temporal coherence within a focused supercontinuum

    SciTech Connect

    Chick, Brendan J.; Chon, James W. M.; Gu Min

    2010-08-15

    Under the conditions of vectorial diffraction, an increase in refraction at the extremities of the lens rotates the incident polarization state which transfers energy from the initial state to the orthogonal transverse field and the longitudinal field, which is known as depolarization. Since the field is a vectorial field containing three polarization components, the theory for the degree of coherence is first extended to incorporate cross-correlation effects within these vectorial components which are calculated through a coherency matrix. The use of this matrix provides an insight into interesting correlation effects between copropagating vectorial fields such as the coupled modes (linear polarized modes) of the supercontinuum generated by a photonic crystal fiber. An investigation is presented on the coherence times for the supercontinuum field generated by cross coupling into the photonic crystal fiber. The coherence times under cross-coupling conditions show that the degree of coherence of the two coupled modes from the fiber are different, which is due to the differences in phase. For a supercontinuum with a linear polarization state, the coherence times along the x, y, and z axes are different, with the most significant change occurring along the optical axis (z) where the coherence time changes by an order of magnitude when the numerical aperture is increased from 0.1 to 1.

  20. 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.

  1. Risk factors for total tooth loss in the United States; longitudinal analysis of national data.

    PubMed

    Eklund, S A; Burt, B A

    1994-01-01

    The NHANES I Epidemiologic Follow-up Study (NHEFS) of 1982-84 collected longitudinal data from 10,523 individuals initially seen during the first National Health and Nutrition Examination Survey (NHANES I) of 1971-75. Among this additional data was information on the incidence of total tooth loss during the 10 years between the surveys, which could then be added to NHANES I data to identify risk factors. In this analysis, a series of bivariate analyses were carried out, followed by logistic regression analysis to assess the simultaneous effect of major variables. Results showed that 7.4 percent of dentate Americans aged 25-74 at NHANES I became edentulous over the next 10 years. In bivariate analyses, the incidence of edentulism was correlated with baseline measures of lower income and education status, poorer oral health, self-perceptions of poor general health and oral health, absence of a regular dentist, and a lower number of remaining teeth at baseline. No correlation was found with gender and geographic region, nor with self-reported diabetes and arthritis, and age was not a factor when the number of remaining teeth at baseline were taken into account. In a logistic regression model assessing the effect of these variables simultaneously, none of the demographic variables retained significance; the only variable statistically significant in both age groups was the number of teeth remaining at baseline. Other significant variables in younger persons were higher periodontal disease scores, perceived poor dental health, perceived need for extractions, history of smoking, and low ascorbic acid intake. Some of these variables were reflections of negative health behavior and attitudes rather than direct correlates. Principal findings from this study were the importance of early tooth loss in eventual edentulism and the virtual disappearance of gender and age as determinants of total tooth loss. PMID:8164192

  2. 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

  3. Assessment of aerosol's mass concentrations from measured linear particle depolarization ratio (vertically resolved) and simulations

    NASA Astrophysics Data System (ADS)

    Nemuc, A.; Vasilescu, J.; Talianu, C.; Belegante, L.; Nicolae, D.

    2013-11-01

    Multi-wavelength depolarization Raman lidar measurements from Magurele, Romania are used in this study along with simulated mass-extinction efficiencies to calculate the mass concentration profiles of different atmospheric components, due to their different depolarization contribution to the 532 nm backscatter coefficient. Linear particle depolarization ratio (δpart) was computed using the relative amplification factor and the system-dependent molecular depolarization. The low depolarizing component was considered as urban/smoke, with a mean δpart of 3%, while for the high depolarizing component (mineral dust) a mean δpart of 35% was assumed. For this study 11 months of lidar measurements were analysed. Two study cases are presented in details: one for a typical Saharan dust aerosol intrusion, 10 June 2012 and one for 12 July 2012 when a lofted layer consisting of biomass burning smoke extended from 3 to 4.5 km height. Optical Properties of Aerosols and Clouds software package (OPAC) classification and conversion factors were used to calculate mass concentrations. We found that calibrated depolarization measurements are critical in distinguishing between smoke-reach aerosol during the winter and dust-reach aerosol during the summer, as well as between elevated aerosol layers having different origins. Good agreement was found between lidar retrievals and DREAM- Dust REgional Atmospheric Model forecasts in cases of Saharan dust. Our method was also compared against LIRIC (The Lidar/Radiometer Inversion Code) and very small differences were observed.

  4. Assessment of aerosol's mass concentrations from measured linear particle depolarization ratio (vertically resolved) and simulations

    NASA Astrophysics Data System (ADS)

    Nemuc, A.; Vasilescu, J.; Talianu, C.; Belegante, L.; Nicolae, D.

    2013-06-01

    Multiwavelength depolarization Raman lidar measurements from Magurele, Romania are used in this study along with simulated mass-extinction efficiencies to calculate the mass concentrations profiles of different atmospheric components, due to their different depolarization contribution to the 532 nm backscatter coefficient. Linear particle depolarization ratio (δpart) was computed using the relative amplification factor and the system-dependent molecular depolarization. The low depolarizing component was considered as urban/smoke, with a mean δpart of 3%, while for the high depolarizing component (mineral dust) a mean δpart of 35% was assumed. For this study 11 months of lidar measurements were analyzed. Two study cases are presented in details: one for a typical Saharan dust aerosol intrusion, 10 June 2012 and one for 12 July 2012 when a lofted layer consisting of biomass burning smoke extended from 3 to 4.5 km height. Optical Properties of Aerosols and Clouds software package (OPAC) classification and conversion factors were used to calculate mass concentrations. We found that calibrated depolarization measurements are critical to distinguish between smoke-reach aerosol during the winter and dust-reach aerosol during the summer, as well as between elevated aerosol layers having different origins. Good agreement was found between lidar retrievals and DREAM- Dust REgional Atmospheric Model forecasts in cases of Saharan dust. Our method was also compared against LIRIC (The Lidar/Radiometer Inversion Code) and very small differences were observed.

  5. Analysis of a compartmental model of amyloid beta production, irreversible loss and exchange in humans

    PubMed Central

    Elbert, Donald L.; Patterson, Bruce W.; Bateman, Randall J.

    2014-01-01

    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. PMID:25497960

  6. 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. PMID:25497960

  7. 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.

  8. An Augmented Classical Least Squares Method for Quantitative Raman Spectral Analysis against Component Information Loss

    PubMed Central

    Zhou, Yan; Cao, Hui

    2013-01-01

    We propose an augmented classical least squares (ACLS) calibration method for quantitative Raman spectral analysis against component information loss. The Raman spectral signals with low analyte concentration correlations were selected and used as the substitutes for unknown quantitative component information during the CLS calibration procedure. The number of selected signals was determined by using the leave-one-out root-mean-square error of cross-validation (RMSECV) curve. An ACLS model was built based on the augmented concentration matrix and the reference spectral signal matrix. The proposed method was compared with partial least squares (PLS) and principal component regression (PCR) using one example: a data set recorded from an experiment of analyte concentration determination using Raman spectroscopy. A 2-fold cross-validation with Venetian blinds strategy was exploited to evaluate the predictive power of the proposed method. The one-way variance analysis (ANOVA) was used to access the predictive power difference between the proposed method and existing methods. Results indicated that the proposed method is effective at increasing the robust predictive power of traditional CLS model against component information loss and its predictive power is comparable to that of PLS or PCR. PMID:23956689

  9. Analysis of loss of off-site power with a PWR at shutdown

    SciTech Connect

    Chu, T.L.; Yoon, W.H.; Fitzpatrick, R.G.

    1987-01-01

    In many probabilistic risk assessments (PRAs), loss of offsite power (LOOP) when a nuclear power plant is operating was found to be a significant contributor to core damage. The purpose of this study is to provide an analysis of a LOOP event that occurs while a pressurized water reactor (PWR) is shut down. The importance of such an analysis was recognized as part of a study to evaluate the core damage frequency due to a loss of decay heat removal (DHR) capability during an outage. When a PWR is in a shutdown condition, there are relatively few technical specification requirements on the operability of safety systems. In fact, some safety systems are intentionally disabled, i.e., the safety injection system and nonoperating charging pumps. Another problem when the reactor is shut down is that the reactor coolant system (RCS) may be partially drained and the steam generators may be unavailable. To determine the time available for operator actions, given that a LOOP occurs during shutdown and the DHR capability is lost, a simple thermal model has been developed. Similar calculations have been performed for other phases of refueling and maintenance outages. A total core damage frequency due to LOOP while the plant is in shutdown has been calculated to be 5.9 x 10/sup -6//yr. This is approximately twice the core damage frequency calculated for LOOP when the plant is at power.

  10. 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.

  11. Fear induced complexity loss in the electrocardiogram of flight phobics: a multiscale entropy analysis.

    PubMed

    Bornas, Xavier; Llabrés, Jordi; Noguera, Miquel; López, Ana M A; Gelabert, Joan Miquel; Vila, Irene

    2006-10-01

    In this study we explored the changes in the variability and complexity of the electrocardiogram (ECG) of flight phobics (N=61) and a matched non-phobic control group (N=58) when they performed a paced breathing task and were exposed to flight related stimuli. Lower complexity/entropy values were expected in phobics as compared to controls. The phobic system complexity as well as the heart rate variability (HRV) were expected to be reduced by the exposure to fearful stimuli. The multiscale entropy (MSE) analysis revealed lower entropy values in phobics during paced breathing and exposure, and a complexity loss was observed in phobics during exposure to threatening situations. The expected HRV decreases were not found in this study. The discussion is focused on the distinction between variability and complexity measures of the cardiac output, and on the usefulness of the MSE analysis in the field of anxiety disorders. PMID:16839658

  12. Chaos analysis of EEG during isoflurane-induced loss of righting in rats.

    PubMed

    MacIver, M B; Bland, Brian H

    2014-01-01

    It has long been known that electroencephalogram (EEG) signals generate chaotic strange attractors and the shape of these attractors correlate with depth of anesthesia. We applied chaos analysis to frontal cortical and hippocampal micro-EEG signals from implanted microelectrodes (layer 4 and CA1, respectively). Rats were taken to and from loss of righting reflex (LORR) with isoflurane and behavioral measures were compared to attractor shape. Resting EEG signals at LORR differed markedly from awake signals, more similar to slow wave sleep signals, and easily discerned in raw recordings (high amplitude slow waves), and in fast Fourier transform analysis (FFT; increased delta power), in good agreement with previous studies. EEG activation stimulated by turning rats on their side, to test righting, produced signals quite similar to awake resting state EEG signals. That is, the high amplitude slow wave activity changed to low amplitude fast activity that lasted for several seconds, before returning to slow wave activity. This occurred regardless of whether the rat was able to right itself, or not. Testing paw pinch and tail clamp responses produced similar EEG activations, even from deep anesthesia when burst suppression dominated the spontaneous EEG. Chaotic attractor shape was far better at discerning between these awake-like signals, at loss of responses, than was FFT analysis. Comparisons are provided between FFT and chaos analysis of EEG during awake walking, slow wave sleep, and isoflurane-induced effects at several depths of anesthesia. Attractors readily discriminated between natural sleep and isoflurane-induced "delta" activity. Chaotic attractor shapes changed gradually through the transition from awake to LORR, indicating that this was not an on/off like transition, but rather a point along a continuum of brain states. PMID:25360091

  13. 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

  14. Longitudinal polarization periodicity of unpolarized light passing through a double wedge depolarizer.

    PubMed

    de Sande, Juan Carlos G; Santarsiero, Massimo; Piquero, Gemma; Gori, Franco

    2012-12-01

    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. PMID:23262685

  15. 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. PMID:27128058

  16. 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

  17. Root-cause failure analysis of photocurrent loss in polythiophene:fullerene-based inverted solar cells.

    PubMed

    Voroshazi, Eszter; Uytterhoeven, Griet; Cnops, Kjell; Conard, Thierry; Favia, Paola; Bender, Hugo; Muller, Robert; Cheyns, David

    2015-01-14

    Metal oxide transport layers have played a crucial role in recent progress in organic photovoltaic (OPV) device stability. Here, we measure the stability of inverted and encapsulated polythiophene:fullerene cells with MoO3/Ag/Al composite anode in operational conditions combining solar radiation and 65 °C. Performance loss of over 50% in the first 100 h of the aging is dominated by a drop in the short-circuit current (Jsc). We reveal a concurrent loss in reflectance from 85% to 50% above 650 nm, which is below the optical gap of the used photoactive materials, hence, excluding any major degradation in the bulk of this layer. Correlating the responses of aged devices to a series of test structures comprised of ITO/ZnO cathode, MoO3/Ag, and MoO3/Ag/Al anodes and their combinations with the active layer allowed us to identify that the presence of Al causes the reduced reflectance in these devices, independent of the presence of the active layer. Systematic single-stress aging on the test structures further indicates that elevated heat is the cause of the reflectance loss. Cross-section transmission electron microscopy coupled with elemental analysis revealed the unsuspected role of Al; notably, it diffuses through the entire 150 nm thick Ag layer and accumulates at the MoO3/Ag interface. Moreover, XRD analysis of the aged MoO3/Ag/Al anode indicates the formation of Ag2Al alloy. Depth profiling with X-ray photoelectron spectroscopy advanced our understanding by confirming the formation of Ag-Al intermetallic alloy and the presence of oxidized Al only at the MoO3/Ag interface suggesting a concomitant reduction of MoO3 to most probably MoO2. This latter compound is less reflective than MoO3, which can explain the reduced reflectance in aged devices as proven by optical simulations. On the basis of these results, we could estimate that 20% of the loss in Jsc is ascribed to reduction of MoO3 triggered by its direct contact with Al. PMID:25536872

  18. 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.

  19. 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)

  20. Neural depolarization triggers Mg2+ influx in rat hippocampal neurons.

    PubMed

    Yamanaka, R; Shindo, Y; Karube, T; Hotta, K; Suzuki, K; Oka, K

    2015-12-01

    Homeostasis of magnesium ion (Mg(2+)) plays key roles in healthy neuronal functions, and deficiency of Mg(2+) is involved in various neuronal diseases. In neurons, we have reported that excitotoxicity induced by excitatory neurotransmitter glutamate increases intracellular Mg(2+) concentration ([Mg(2+)]i). However, it has not been revealed whether neuronal activity under physiological condition modulates [Mg(2+)]i. The aim of this study is to explore the direct relationship between neural activity and [Mg(2+)]i dynamics. In rat primary-dissociated hippocampal neurons, the [Mg(2+)]i and [Ca(2+)]i dynamics were simultaneously visualized with a highly selective fluorescent Mg(2+) probe, KMG-104, and a fluorescent Ca(2+) probe, Fura Red, respectively. [Mg(2+)]i increase concomitant with neural activity by direct current stimulation was observed in neurons plated on an indium-tin oxide (ITO) glass electrode, which enables fluorescent imaging during neural stimulation. The neural activity-dependent [Mg(2+)]i increase was also detected in neurons whose excitability was enhanced by the treatment of a voltage-gated K(+) channel blocker, tetraethylammonium (TEA) at the timings of spontaneous Ca(2+) increase. Furthermore, the [Mg(2+)]i increase was abolished in Mg(2+)-free extracellular medium, indicating [Mg(2+)]i increase is due to Mg(2+) influx induced by neural activity. The direct neuronal depolarization by veratridine, a Na(+) channel opener, induced [Mg(2+)]i increase, and this [Mg(2+)]i increase was suppressed by the pretreatment of a non-specific Mg(2+) channel inhibitor, 2-aminoethoxydiphenyl borate (2-APB). Overall, activity-dependent [Mg(2+)]i increase results from Mg(2+) influx through 2-APB-sensitive channels in rat hippocampal neurons. PMID:26455951

  1. Comparative Transcriptome Analysis of Anthurium “Albama” and Its Anthocyanin-Loss Mutant

    PubMed Central

    Zhang, Xuequan; Xu, Li

    2015-01-01

    Anthurium is one of the most important tropical ornamental plants in the world. The traded value of anthurium is second only to that of tropical orchids among the tropical flowers. The spathe is the main ornamental organ and its color variation mainly arises from anthocyanin contents. Understanding the molecular regulation of spathe color will accelerate new variety creation of anthurium. To announce gene expression differences between Anthurium andraeanum ‘Albama’ and its one unique anthocyanin-loss mutant, we collected spathes of the wild-type and the mutant from two stages in spathe development (the flower separates protrude from the sheath and the spathe is fully expanded) and extracted total RNAs for transcriptome profiling. Using short read sequencing technology (Illumina), 51,955,564, 53,822,224, 54,221,990 and 52,276,418 sequencing raw reads, respectively, for wild-type and mutant in the two stages were assembled de novo into 111,268 unique sequences (unigenes) with a mean length of 652 bp. 47,563 unigenes had significant hits to the sequences in the Nr database, and 32,768 unigenes showed significant similarity to known proteins in the Swiss-Prot database. 28,350 and 19,293 unigenes had significant similarity to existing sequences in the KEGG and COG databases, respectively. Further, analysis of differentially expressed genes in the comparison between wild-type and mutant and between the two different developmental stages was carried out, indicating that the expression of an extensive set of genes changed as the result of mutation. Taken together, these data demonstrated that the Illumina sequencing allowed de novo transcriptome assembly and could obtain differentially expressed genes between A. andraeanum wild-type and the anthocyanin-loss mutant. The expression differences of AN2 and UFGT might cause the anthocyanin-loss mutation. PMID:25781998

  2. Ranking paths in statistical energy analysis models with non-deterministic loss factors

    NASA Astrophysics Data System (ADS)

    Aragonès, Àngels; Guasch, Oriol

    2015-02-01

    Finding the contributions of transmission paths in statistical energy analysis (SEA) models has become an established valuable tool to detect and remedy vibro-acoustic problems. Paths are identified in SEA according to Craik's definition and recently, very efficient methods have been derived to rank them in the framework of graph theory. However, up to date classification schemes have only considered the mean values of loss factors for path comparison, their variance being ignored. This can result in significant errors in the final results. In this work it is proposed to address this problem by defining stochastic biparametric SEA graphs whose edges are assigned both, mean and variance values. Paths between subsystems are then compared according to a proposed cost function that accounts for the stochastic nature of loss factors. For an efficacious ranking of paths, the stochastic SEA graph is converted to an extended deterministic SEA graph where fast classification deterministic algorithms can be applied. The importance of nonneglecting the influence of the variance in path ranking is illustrated by means of some academic numerical examples.

  3. 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.

  4. Magnetic Flux Leakage and Principal Component Analysis for metal loss approximation in a pipeline

    NASA Astrophysics Data System (ADS)

    Ruiz, M.; Mujica, L. E.; Quintero, M.; Florez, J.; Quintero, S.

    2015-07-01

    Safety and reliability of hydrocarbon transportation pipelines represent a critical aspect for the Oil an Gas industry. Pipeline failures caused by corrosion, external agents, among others, can develop leaks or even rupture, which can negatively impact on population, natural environment, infrastructure and economy. It is imperative to have accurate inspection tools traveling through the pipeline to diagnose the integrity. In this way, over the last few years, different techniques under the concept of structural health monitoring (SHM) have continuously been in development. This work is based on a hybrid methodology that combines the Magnetic Flux Leakage (MFL) and Principal Components Analysis (PCA) approaches. The MFL technique induces a magnetic field in the pipeline's walls. The data are recorded by sensors measuring leakage magnetic field in segments with loss of metal, such as cracking, corrosion, among others. The data provide information of a pipeline with 15 years of operation approximately, which transports gas, has a diameter of 20 inches and a total length of 110 km (with several changes in the topography). On the other hand, PCA is a well-known technique that compresses the information and extracts the most relevant information facilitating the detection of damage in several structures. At this point, the goal of this work is to detect and localize critical loss of metal of a pipeline that are currently working.

  5. [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. PMID:26710649

  6. 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.

  7. 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.

  8. 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.

  9. Suppression of Ultracold Neutron Depolarization on Material Surfaces with Magnetic Holding Fields

    NASA Astrophysics Data System (ADS)

    Rios, Raymond

    2009-05-01

    The depolarization of Ultracold Neutrons(UCN) was measured within 1-m long, 2 3/4" diameter electropolished copper, diamondlike carbon-coated copper, and stainless steel guide tubes as a function of magnetic holding field. The UCN were trapped between a 6 Tesla solenoidal magnetic field and a 3/8" copper aperture. A series of Helmholtz coils produced a magnetic field over the length of the test guide of either 10 or 250 Gauss. The surface depolarization was observed to be suppressed at the higher holding field on the measured copper guides. These measurements will aid in the determination of the upper limit of depolarization of UCN in the UCN beta asymmetry measurement at LANL (UCNA) and in understanding the mechanisms for depolarization in non-magnetic guides.

  10. 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

  11. Thermally induced depolarization in terbium gallium garnet ceramics rod with natural convection cooling

    NASA Astrophysics Data System (ADS)

    Slezak, Ondrej; Yasuhara, Ryo; Lucianetti, Antonio; Vojna, David; Mocek, Tomas

    2015-06-01

    Thermal birefringence-induced depolarization in terbium gallium garnet (TGG) ceramic rods has been numerically evaluated for the geometry and heating conditions in a previous experiment. In this model, the spatially resolved heat transfer coefficient corresponding to natural convection cooling and the offset of the beam from the rotational axis of the rod have been incorporated and the realistic beam profile used in the experiment has been considered. A resulting beam depolarization ratio of 4.3 × 10-4 has been calculated for an input power of 117 W. The results were found to be in good agreement with the measured values. Furthermore, a parametric study of the depolarization ratio for higher input powers has been performed leading to a depolarization ratio of 3.3 × 10-2 for 1 kW input power.

  12. Depolarization of cell membrane is associated with an increase in ciliary beat frequency (CBF).

    PubMed

    Mao, H; Wong, L B

    1995-10-24

    We hypothesize that activation of muscarinic cholinergic receptors depolarizes the cell membrane of the mammalian ciliated cells which in turn causes an increase of CBF. To test this hypothesis, a di-8-ANEPPS fluorescence photon counting and nonstationary heterodyne laser light scattering system was developed to measure cell membrane potential (psi) and CBF in cultured ovine tracheal ciliated cells simultaneously. Carbachol dose dependently depolarized the cell membrane with a corresponding stimulation of CBF. The carbachol induced depolarization of cell membrane and increases of CBF were inhibited by prior application of either atropine or verapamil or amiloride. These novel data suggest that depolarization of the cell membrane and the corresponding stimulation of CBF caused by the activation of muscarinic receptors of the mammalian ciliated cells are dependent on the influx of either extracellular Ca2+ or Na+. PMID:7488025

  13. Conceptual design loss-of-coolant accident analysis for the Advanced Neutron Source reactor

    SciTech Connect

    Chen, N.C.J.; Wendel, M.W.; Yoder, G.L. Jr. )

    1994-01-01

    A RELAP5 system model for the Advanced Neutron Source Reactor has been developed for performing conceptual safety analysis report calculations. To better represent thermal-hydraulic behavior of the core, three specific changes in the RELAP5 computer code were implemented: a turbulent forced-convection heat transfer correlation, a critical heat flux (CHF) correlation, and an interfacial drag correlation. The model consists of the core region, the heat exchanger loop region, and the pressurizing/letdown system region. Results for three loss-of-coolant accident analyses are presented: (1) an instantaneous double-ended guillotine (DEG) core outlet break with a cavitating venturi installed downstream of the core, (b) a core pressure boundary tube outer wall rupture, and (c) a DEG core inlet break with a finite break-formation time. The results show that the core can survive without exceeding the flow excursion of CHF thermal limits at a 95% probability level if the proper mitigation options are provided.

  14. PAX3 gene deletion detected by microarray analysis in a girl with hearing loss.

    PubMed

    Drozniewska, Malgorzata; Haus, Olga

    2014-01-01

    Deletions of the PAX3 gene have been rarely reported in the literature. Mutations of this gene are a common cause of Waardenburg syndrome type 1 and 3. We report a 16 year old female presenting hearing loss and normal intellectual development, without major features of Waardenburg syndrome type 1, and without family history of the syndrome. Her phenotype, however, overlaps with features of craniofacial-deafness-hand syndrome. Microarray analysis showed ~862 kb de novo deletion at 2q36.1 including PAX3. The above findings suggest that the rearrangement found in our patient appeared de novo and with high probability is a cause of her phenotype. PMID:24839464

  15. Analysis of BRCA2 loss of heterozygosity in tumor tissue using droplet digital polymerase chain reaction.

    PubMed

    Cochran, Rory L; Cravero, Karen; Chu, David; Erlanger, Bracha; Toro, Patricia Valda; Beaver, Julia A; Zabransky, Daniel J; Wong, Hong Yuen; Cidado, Justin; Croessmann, Sarah; Parsons, Heather A; Kim, Minsoo; Wheelan, Sarah J; Argani, Pedram; Park, Ben Ho

    2014-07-01

    Loss-of-heterozygosity (LOH) analysis of archival tumor tissue can aid in determining the clinical significance of BRCA variants. Here we describe an approach for assessing LOH in formalin-fixed, paraffin-embedded (FFPE) tissues using variant-specific probes and droplet digital polymerase chain reaction (ddPCR). We evaluated LOH in 2 related breast cancer patients harboring a rare missense BRCA2 variant of unknown clinical significance (c.6966G>T; M2322I). Conventional PCR followed by Sanger sequencing suggested a change in allelic abundance in the FFPE specimens. However, we found no evidence of LOH as determined by the allelic ratio (wild type-variant) for BRCA2 in both patients' archival tumor specimens and adjacent normal control tissues using ddPCR. In summary, these experiments demonstrate the utility of ddPCR to quickly and accurately assess LOH in archival FFPE tumor tissue. PMID:24824029

  16. 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.

  17. 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.

  18. 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.

  19. 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)

  20. Loss of PEG chain in routine SDS-PAGE analysis of PEG-maleimide modified protein.

    PubMed

    Zhang, Chun; Liu, Yongdong; Feng, Cui; Wang, Qi; Shi, Hong; Zhao, Dawei; Yu, Rong; Su, Zhiguo

    2015-01-01

    SDS-PAGE represents a quick and simple method for qualitative and quantitative analysis of protein and protein-containing conjugates, mostly pegylated proteins. PEG-maleimide (MAL) is frequently used to site-specifically pegylate therapeutic proteins via free cysteine residue by forming a thiosuccinimide structure for pursuing homogeneous products. The C-S linkage between protein and PEG-MAL is generally thought to be relatively stable. However, loss of intact PEG chain in routine SDS-PAGE analysis of PEG-maleimide modified protein was observed. It is a thiol-independent thioether cleavage and the shedding of PEG chain exclusively happens to PEG-MAL modified conjugates although PEG-vinylsulfone conjugates to thiol-containing proteins also through a C-S linkage. Cleavage kinetics of PEG40k-MAL modified ciliary neurotrophic factor showed this kind of degradation could immediately happen even in 1 min incubation at high temperature and could be detected at physiological temperature and pH, although the rate was relatively slow. This may provide another degradation route for maleimide-thiol conjugate irrespective of reactive thiol, although the specific mechanism is still not very clear for us. It would also offer a basis for accurate characterization of PEG-MAL modified protein/peptide by SDS-PAGE analysis. PMID:25265901

  1. 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. PMID:26002688

  2. 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.

  3. Control of cyclic adenosine 3',5'-monophosphate levels by depolarizing agents in fungi.

    PubMed Central

    Trevillyan, J M; Pall, M L

    1979-01-01

    It has been reported that diverse treatments which depolarize the plasma membrane of Neurospora crassa produce rapid increases in cyclic adenosine 3',5'-monophosphate (cyclic AMP) levels. In the current study, membrane active antibiotics, which are known or putative depolarizing agents, were found to produce similar cyclic AMP increases, not only in N. crassa, but also in the distantly related fungi Saccharomyces cerevisiae and Mucor racemosus. Uncouplers of oxidative phosphorylation, which have been found to depolarize Neurospora, also produced cyclic AMP increases in all three fungi. The time course of the cyclic AMP response to these various treatments was similar in all three fungi. The fungal studies and studies on depolarized central nervous tissue suggest that cyclic AMP increases may be produced in response to plasma membrane depolarization in diverse eucaryotic cells. A model is proposed for eucaryotic microorganisms in which membrane depolarization serves as a signal of breakdown of the plasma membrane integrity. The subsequent cyclic AMP increase, in turn, may mediate cellular response to help protect the plasma membrane from chemical and mechanical threats to its integrity. PMID:220213

  4. 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.

  5. Polyamines cause plasma membrane depolarization, activate Ca2+-, and modulate H+-ATPase pump activity in pea roots.

    PubMed

    Pottosin, Igor; Velarde-Buendía, Ana María; Bose, Jayakumar; Fuglsang, Anja T; Shabala, Sergey

    2014-06-01

    Polyamines regulate a variety of cation and K(+) channels, but their potential effects on cation-transporting ATPases are underexplored. In this work, noninvasive microelectrode ion flux estimation and conventional microelectrode techniques were applied to study the effects of polyamines on Ca(2+) and H(+) transport and membrane potential in pea roots. Externally applied spermine or putrescine (1mM) equally activated eosin yellow (EY)-sensitive Ca(2+) pumping across the root epidermis and caused net H(+) influx or efflux. Proton influx induced by spermine was suppressed by EY, supporting the mechanism in which Ca(2+) pump imports 2 H(+) per each exported Ca(2+). Suppression of the Ca(2+) pump by EY diminished putrescine-induced net H(+) efflux instead of increasing it. Thus, activities of Ca(2+) and H(+) pumps were coupled, likely due to the H(+)-pump inhibition by intracellular Ca(2+). Additionally, spermine but not putrescine caused a direct inhibition of H(+) pumping in isolated plasma membrane vesicles. Spermine, spermidine, and putrescine (1mM) induced membrane depolarization by 70, 50, and 35 mV, respectively. Spermine-induced depolarization was abolished by cation transport blocker Gd(3+), was insensitive to anion channels' blocker niflumate, and was dependent on external Ca(2+). Further analysis showed that uptake of polyamines but not polyamine-induced cationic (K(+)+Ca(2+)+H(+)) fluxes were a main cause of membrane depolarization. Polyamine increase is a common component of plant stress responses. Activation of Ca(2+) efflux by polyamines and contrasting effects of polyamines on net H(+) fluxes and membrane potential can contribute to Ca(2+) signalling and modulate a variety of transport processes across the plasma membrane under stress. PMID:24723394

  6. Photogeneration of membrane potential hyperpolarization and depolarization in non-excitable cells.

    PubMed

    Ando, Jun; Smith, Nicholas I; Fujita, Katsumasa; Kawata, Satoshi

    2009-02-01

    We monitored femtosecond laser induced membrane potential changes in non-excitable cells using patchclamp analysis. Membrane potential hyperpolarization of HeLa cells was evoked by 780 nm, 80 fs laser pulses focused in the cellular cytoplasm at average powers of 30-60 mW. Simultaneous detection of intracellular Ca2+ concentration and membrane potential revealed coincident photogeneration of Ca2+ waves and membrane potential hyperpolarization. By using non-excitable cells, the cell dynamics are slow enough that we can calculate the membrane potential using the steady-state approximation for ion gradients and permeabilities, as formulated in the GHK equations. The calculations predict hyperpolarization that matches the experimental measurements and indicates that the cellular response to laser irradiation is biological, and occurs via laser triggered Ca2+ which acts on Ca2+ activated K+ channels, causing hyperpolarization. Furthermore, by irradiating the cellular plasma membrane, we observed membrane potential depolarization in combination with a drop in membrane resistance that was consistent with a transient laser-induced membrane perforation. These results entail the first quantitative analysis of location-dependent laser-induced membrane potential modification and will help to clarify cellular biological responses under exposure to high intensity ultrashort laser pulses. PMID:19137284

  7. 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. PMID:26368203

  8. Depolarization counteracts glucocorticoid inhibition of adenohypophysical corticotroph cells

    PubMed Central

    Lim, M C; Shipston, M J; Antoni, F A

    1998-01-01

    mM CPT-cAMP-induced ACTH secretion by 100 nM dexamethasone. In primary cultures of rat anterior pituitary cells, depolarization of the membrane potential with 40 mM KCl enhanced the ACTH response to CPT-cAMP and markedly reduced the maximal inhibitory effect of dexamethasone to 55±1.2% as well as that of corticosterone to 33±2.1% vs 100±2.5% and 100±1.9% inhibition respectively, when 0.1 mM CPT-cAMP was used alone. Introduction of 5 μM (−)BayK8644 with 40 mM KCl in this system had no additional effect on glucocorticoid inhibition. No glucocorticoid inhibition of ACTH release to any of the stimuli applied was observed in cells pretreated with the mRNA synthesis inhibitor, 5,6-dichloro-furanosyl-benzimidazole riboside (DRB) (0.1 mM) or the protein synthesis blocker, puromycin (0.1 mM). In summary, early glucocorticoid inhibition of stimulated ACTH release by cultured rat anterior pituitary cells was dependent on the synthesis of new mRNA and protein. Depolarization of the membrane potential potentiated CPT-cAMP-induced ACTH secretion in AtT20 cells as well as cultured rat corticotrophs and this was associated with a resistance to the early inhibitory effect of glucocorticoids. Glucocorticoid inhibition in rat anterior pituitary corticotrophs was unaltered by TEA, charybdotoxin as well as apamin, and hence it is unlikely to involve predominantly BK-or SK-type Ca2+-activated K+-channels. These results support the thesis that a prime target of glucocorticoid feedback inhibition in anterior pituitary corticotrophs is the membrane potential and indicate that glucocorticoid-induced proteins regulate the activities of several distinct plasma membrane ion channels. PMID:9756391

  9. 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.

  10. Quantitative fluorescence loss in photobleaching for analysis of protein transport and aggregation

    PubMed Central

    2012-01-01

    Background Fluorescence loss in photobleaching (FLIP) is a widely used imaging technique, which provides information about protein dynamics in various cellular regions. In FLIP, a small cellular region is repeatedly illuminated by an intense laser pulse, while images are taken with reduced laser power with a time lag between the bleaches. Despite its popularity, tools are lacking for quantitative analysis of FLIP experiments. Typically, the user defines regions of interest (ROIs) for further analysis which is subjective and does not allow for comparing different cells and experimental settings. Results We present two complementary methods to detect and quantify protein transport and aggregation in living cells from FLIP image series. In the first approach, a stretched exponential (StrExp) function is fitted to fluorescence loss (FL) inside and outside the bleached region. We show by reaction–diffusion simulations, that the StrExp function can describe both, binding/barrier–limited and diffusion-limited FL kinetics. By pixel-wise regression of that function to FL kinetics of enhanced green fluorescent protein (eGFP), we determined in a user-unbiased manner from which cellular regions eGFP can be replenished in the bleached area. Spatial variation in the parameters calculated from the StrExp function allow for detecting diffusion barriers for eGFP in the nucleus and cytoplasm of living cells. Polyglutamine (polyQ) disease proteins like mutant huntingtin (mtHtt) can form large aggregates called inclusion bodies (IB’s). The second method combines single particle tracking with multi-compartment modelling of FL kinetics in moving IB’s to determine exchange rates of eGFP-tagged mtHtt protein (eGFP-mtHtt) between aggregates and the cytoplasm. This method is self-calibrating since it relates the FL inside and outside the bleached regions. It makes it therefore possible to compare release kinetics of eGFP-mtHtt between different cells and experiments. Conclusions We

  11. Analysis of power loss data for the 200 Area Tank Farms in support of K Basin SAR work

    SciTech Connect

    Shultz, M.V. Jr.

    1994-12-01

    An analysis of power loss data for the 200 Area Tank Farms was performed in support of K Basin safety analysis report work. The purpose of the analysis was to establish a relationship between the length of a power outage and its yearly frequency. This relationship can be used to determine whether the duration of a specific power loss is a risk concern. The information was developed from data contained in unusual occurrence reports (UORs) spanning a continuous period of 19.75 years. The average frequency of power loss calculated from the UOR information is 1.22 events per year. The mean of the power loss duration is 32.5 minutes an the median duration is 2 minutes. Nine events resulted in loss of power to both 200 East and 200 West areas simultaneously. Seven events (not necessarily the same events that resulted in loss of power to both 200 areas) resulted in outage durations exceeding 5 minutes. Approximately one-half of the events were caused by human error. The other half resulted from natural phenomena or equipment failures. None of the outages were reported to have any adverse effect on the tank farms.

  12. 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.

  13. Cerenkov losses: a limit for bandgap determination and Kramers-Kronig analysis.

    PubMed

    Stöger-Pollach, M; Franco, H; Schattschneider, P; Lazar, S; Schaffer, B; Grogger, W; Zandbergen, H W

    2006-01-01

    Measuring low energy losses in semiconductors and insulators with high spatial resolution becomes attractive with the increasing availability of modern transmission electron microscopes (TEMs) equipped with monochromators, C(s) correctors and energy filters. In this paper, we demonstrate that Cerenkov losses pose a limit for the interpretation of low energy loss spectra (EELS) in terms of interband transistions and bandgap determination for many materials. If the velocity of a charged particle in a medium exceeds the velocity of light, photons are emitted leading to a corresponding energy loss of a few electronvolt. Since these losses are strong for energies below the onset of interband transitions, they change the apparent loss function of semiconductors and insulators, with the risk of erroneous interpretation of spectra. We measured low energy losses of Si and GaAs with a monochromated TEM demonstrating the effect of sample thickness on Cerenkov losses. Angle resolved EELS and energy filtered diffraction patterns (taken without a monochromator) show the extremely narrow angular distribution of Cerenkov losses. The latter experiment provides a method that allows to decide whether Cerenkov radiation masks the very low loss signal in EELS. PMID:16551502

  14. 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

  15. The physostigmine depolarization potentiating effect of salicylate in frog skeletal muscle.

    PubMed

    Varga, E; Kovács, L; Szücs, G; Illés, B

    1975-01-01

    1) The frog's sartorius muscle was depolarized depending on the degree of concentration 2--4 times more intensely by physostigmine salicylate than by physostigmine sulphate. 2) In normal Ringer's solution, 1 mM physostigmine salicylate decreased the sensitivity of the membrane to potassium depolarization by about 90%. Under similar experimental conditions, physostigmine sulphate and Na salicylate, respectively, decrease the sensitivity of the membrane to potassium depolarization by about 30%. 3) The difference manifested in the depolarizing effect of salicylate and other physostigmine salts (chloride, sulphate, phosphate, formiate, acetate, monochloracetate, benzoate and para-oxy-benzoate) is expressed already at 1 mM concentration (about 10-fold), if the muscle had been equilibrated in chloride-free glucuronate or sulphate milieu. 4) The depolarization develops slowly. It takes 30--60 minutes for the new steady state to develop even in the superficial sartorius fibres. If depolarization has reached its maximum on an average 100 mV, the membrane potential remains unchanged for hours. 5) Depolarization ensues at an unchanged degree in the presence of Na-free (choline) Ringer as well as in the presence of 2X10(-8) g/ml tetrodotoxin; therefore, it is not a Na-dependent process. 6) Under the influence of 1 mM physostigmine salicylate the membrane's resistance to the inward potassium current increased about twofold, while the increase was only 15% to the outward potassium current. It is assumed that the salicylate anion is characteristically capable of potentiating the decreasing effect of physostigmine on potassium permeability, though the role of the metabolic effect of salicylate cannot be excluded. PMID:1235230

  16. Spreading depolarizations increase delayed brain injury in a rat model of subarachnoid hemorrhage.

    PubMed

    Hamming, Arend M; Wermer, Marieke Jh; Umesh Rudrapatna, S; Lanier, Christian; van Os, Hine Ja; van den Bergh, Walter M; Ferrari, Michel D; van der Toorn, Annette; van den Maagdenberg, Arn Mjm; Stowe, Ann M; Dijkhuizen, Rick M

    2016-07-01

    Spreading depolarizations may contribute to delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage, but the effect of spreading depolarizations on brain lesion progression after subarachnoid hemorrhage has not yet been assessed directly. Therefore, we tested the hypothesis that artificially induced spreading depolarizations increase brain tissue damage in a rat model of subarachnoid hemorrhage. Subarachnoid hemorrhage was induced by endovascular puncture of the right internal carotid bifurcation. After one day, brain tissue damage was measured with T2-weighted MRI, followed by application of 1 M KCl (SD group, N = 16) or saline (no-SD group, N = 16) to the right cortex. Cortical laser-Doppler flowmetry was performed to record spreading depolarizations. MRI was repeated on day 3, after which brains were extracted for assessment of subarachnoid hemorrhage severity and histological damage. 5.0 ± 2.7 spreading depolarizations were recorded in the SD group. Subarachnoid hemorrhage severity and mortality were similar between the SD and no-SD groups. Subarachnoid hemorrhage-induced brain lesions expanded between days 1 and 3. This lesion growth was larger in the SD group (241 ± 233 mm(3)) than in the no-SD group (29 ± 54 mm(3)) (p = 0.001). We conclude that induction of spreading depolarizations significantly advances lesion growth after experimental subarachnoid hemorrhage. Our study underscores the pathophysiological consequence of spreading depolarizations in the development of delayed cerebral tissue injury after subarachnoid hemorrhage. PMID:26661246

  17. Analysis on key problems of mountain torrent disaster loss assessment system in Liaohe River Basin

    NASA Astrophysics Data System (ADS)

    Chen, Jing

    2014-01-01

    Liaohe river basin mountain torrent disaster serious, this paper tells a system of flood loss assessment which would be helpful for the decrease of the geologic disastrous loss. Firstly, it mainly analyzes four uncertainties aspects of flood loss: precision of prediction and simulation, accounting standard of asset, asset vulnerability and flood prevention ability. Secondly, EasyDHM has been selected for forecast flood, the simulation forecast time is 6h before real flood peak coming; flood inundation model is selected for flood submerged level information extracted and flood submerged map. In the end, the model of flood Lose calculation is used to calculation the loss by the extracted information from stacking social economic data and water data. The feasibility of flood loss assessment system has been proved by flood simulation in 1998, 2003 and 2005. The unified assessment criteria make the assessment result difference, but this system of flood loss assessment has some value in system integration.

  18. Engineering and computer analysis methods of determining utility system losses from published data

    SciTech Connect

    Not Available

    1981-11-01

    The purpose of this study was to verify the methodology developed in the previous study, Transmission and Distribution System Loss Study. The data, estimates, assumptions, and calculation methods of the original study were checked against the actual Niagara Mohawk system data. Losses calculated were compared to the system losses derived from actual system data. Revisions to the original methods were recommended to improve the accuracy of the results.

  19. 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. PMID:25909247

  20. 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. PMID:26479926

  1. 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

  2. Visualization analysis of research frontiers and trends in nerve regeneration and osseoperception in the repair of tooth loss

    PubMed Central

    Zhang, Xiaoge; Tang, Tian; Zhao, Zhihe; Zheng, Leilei; Ding, Yin

    2014-01-01

    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. PMID:25598785

  3. Analysis of the TREAT loss-of-flow tests L6 and L7 using SAS3D

    SciTech Connect

    Morris, E.E.; Simms, R.; Gruber, E.E.

    1985-01-01

    The TREAT loss-of-flow tests L6 and L7 have been analyzed using the SAS3D accident analysis code. The impetus for the analysis was the need for experimentally supported fuel motion modeling in whole core accident studies performed in support of licensing of the Clinch River Breeder Reactor Project. The input prescription chosen for the SAS3D/SLUMPY fuel motion model gave reasonable agreement with the test results. Tests L6 and L7, each conducted with a cluster of three fuel pins, were planned to simulate key events in the loss-of-flow accident scenario for the Clinch River homogeneous reactor.

  4. 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.

  5. 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.

  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. 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 PMID:26011790

  8. 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

  9. 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. PMID:24707214

  10. Genomic Analysis Reveals the Molecular Basis for Capsule Loss in the Group B Streptococcus Population

    PubMed Central

    Rosini, Roberto; Campisi, Edmondo; De Chiara, Matteo; Tettelin, Hervé; Rinaudo, Daniela; Toniolo, Chiara; Metruccio, Matteo; Guidotti, Silvia; Sørensen, Uffe B. Skov; Kilian, Mogens; Ramirez, Mario; Janulczyk, Robert; Donati, Claudio; Grandi, Guido; Margarit, Immaculada

    2015-01-01

    The human and bovine bacterial pathogen Streptococcus agalactiae (Group B Streptococcus, GBS) expresses a thick polysaccharide capsule that constitutes a major virulence factor and vaccine target. GBS can be classified into ten distinct serotypes differing in the chemical composition of their capsular polysaccharide. However, non-typeable strains that do not react with anti-capsular sera are frequently isolated from colonized and infected humans and cattle. To gain a comprehensive insight into the molecular basis for the loss of capsule expression in GBS, a collection of well-characterized non-typeable strains was investigated by genome sequencing. Genome based phylogenetic analysis extended to a wide population of sequenced strains confirmed the recently observed high clonality among GBS lineages mainly containing human strains, and revealed a much higher degree of diversity in the bovine population. Remarkably, non-typeable strains were equally distributed in all lineages. A number of distinct mutations in the cps operon were identified that were apparently responsible for inactivation of capsule synthesis. The most frequent genetic alterations were point mutations leading to stop codons in the cps genes, and the main target was found to be cpsE encoding the portal glycosyl trasferase of capsule biosynthesis. Complementation of strains carrying missense mutations in cpsE with a wild-type gene restored capsule expression allowing the identification of amino acid residues essential for enzyme activity. PMID:25946017

  11. Genomic analysis reveals the molecular basis for capsule loss in the group B Streptococcus population.

    PubMed

    Rosini, Roberto; Campisi, Edmondo; De Chiara, Matteo; Tettelin, Hervé; Rinaudo, Daniela; Toniolo, Chiara; Metruccio, Matteo; Guidotti, Silvia; Sørensen, Uffe B Skov; Kilian, Mogens; Ramirez, Mario; Janulczyk, Robert; Donati, Claudio; Grandi, Guido; Margarit, Immaculada

    2015-01-01

    The human and bovine bacterial pathogen Streptococcus agalactiae (Group B Streptococcus, GBS) expresses a thick polysaccharide capsule that constitutes a major virulence factor and vaccine target. GBS can be classified into ten distinct serotypes differing in the chemical composition of their capsular polysaccharide. However, non-typeable strains that do not react with anti-capsular sera are frequently isolated from colonized and infected humans and cattle. To gain a comprehensive insight into the molecular basis for the loss of capsule expression in GBS, a collection of well-characterized non-typeable strains was investigated by genome sequencing. Genome based phylogenetic analysis extended to a wide population of sequenced strains confirmed the recently observed high clonality among GBS lineages mainly containing human strains, and revealed a much higher degree of diversity in the bovine population. Remarkably, non-typeable strains were equally distributed in all lineages. A number of distinct mutations in the cps operon were identified that were apparently responsible for inactivation of capsule synthesis. The most frequent genetic alterations were point mutations leading to stop codons in the cps genes, and the main target was found to be cpsE encoding the portal glycosyl transferase of capsule biosynthesis. Complementation of strains carrying missense mutations in cpsE with a wild-type gene restored capsule expression allowing the identification of amino acid residues essential for enzyme activity. PMID:25946017

  12. 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.

  13. 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. PMID:25217083

  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. Quantitative correlation between light depolarization and transport albedo of various porcine tissues

    NASA Astrophysics Data System (ADS)

    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.

  16. Tooth loss is associated with increased risk of esophageal cancer: evidence from a meta-analysis with dose-response analysis

    PubMed Central

    Chen, Qi-Lin; Zeng, Xian-Tao; Luo, Zhi-Xiao; Duan, Xiao-Li; Qin, Jie; Leng, Wei-Dong

    2016-01-01

    Epidemiological studies have revealed the association between tooth loss and the risk of esophageal cancer (EC); however, consistent results were not obtained from different single studies. Therefore, we conducted the present meta-analysis to evaluate the association between tooth loss and EC. We conducted electronic searches of PubMed until to February 10, 2015 to identify relevant observational studies that examined the association between tooth loss and the risk of EC. Study selection and data extraction from eligible studies were independently performed by two authors. The meta-analysis was conducted using Stata 12.0 software. Finally eight eligible publications with ten studies involving 3 cohort studies, 5 case-control studies, and 1 cross-sectional study were yielded. Meta-analysis identified tooth loss increased risk of EC 1.30 times (Relative risk = 1.30, 95% confidence interval = 1.06–1.60, I2 = 13.5%). Dose-response analysis showed linear relationship between tooth loss and risk of EC (RR = 1.01, 95%CI = 1.00–1.03; P for non-linearity test was 0.45). Subgroup analysis proved similar results and publication bias was not detected. In conclusion, tooth loss could be considered to be a significant and dependent risk factor for EC based on the current evidence. PMID:26742493

  17. Parameter uncertainty analysis for the annual phosphorus loss estimator (APLE) model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  18. 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…

  19. 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.

  20. 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.

  1. Hearing Loss

    MedlinePlus

    ... version of this page please turn Javascript on. Hearing Loss What is Hearing Loss? Hearing loss is a common problem caused by ... sec Click to watch this video Types of Hearing Loss Hearing loss comes in many forms. It can ...

  2. Fault tree analysis for data-loss in long-term monitoring networks.

    PubMed

    Dirksen, J; ten Veldhuis, J A E; Schilperoort, R P S

    2009-01-01

    Prevention of data-loss is an important aspect in the design as well as the operational phase of monitoring networks since data-loss can seriously limit intended information yield. In the literature limited attention has been paid to the origin of unreliable or doubtful data from monitoring networks. Better understanding of causes of data-loss points out effective solutions to increase data yield. This paper introduces FTA as a diagnostic tool to systematically deduce causes of data-loss in long-term monitoring networks in urban drainage systems. In order to illustrate the effectiveness of FTA, a fault tree is developed for a monitoring network and FTA is applied to analyze the data yield of a UV/VIS submersible spectrophotometer. Although some of the causes of data-loss cannot be recovered because the historical database of metadata has been updated infrequently, the example points out that FTA still is a powerful tool to analyze the causes of data-loss and provides useful information on effective data-loss prevention. PMID:19700829

  3. Light-evoked depolarizations in the retina of Strombus: role of sodium and potassium ions.

    PubMed

    Chinn, K S; Gillary, H L

    1985-01-01

    Light-evoked depolarizations (LED's) in retinal cells of Strombus luhuanus can exhibit an early phase of depolarization (DE), a brief repolarizing phase (RE), and a later depolarizing phase (DL). Lowering external Na+ by substitution with choline, tetramethylammonium or sucrose, reduced the amplitude of the entire LED, but DL was reduced more than DE. Replacement of Na+ with Li+ reduced DE more than DL. Lowering pH reduced DL more than DE, while raising it increased DL but not DE. K+ channel blocking agents, tetraethylammonium and 4-aminopyridine, increased RE. During the LED, cell membrane conductance increased in two phases, corresponding to DE and DL. The results suggest LED generation by two separable conductance increases to Na+, corresponding to DE and DL, and another to K+ during RE. PMID:2579764

  4. 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.

  5. Coherence and polarization of polarization speckle generated by a rough-surfaced retardation plate depolarizer.

    PubMed

    Ma, Ning; Hanson, Steen G; Takeda, Mitsuo; Wang, Wei

    2015-12-01

    The coherence and polarization of polarization speckle, arising from a stochastic electromagnetic field with random change of polarization, modulated by a depolarizer are examined on the basis of the coherence matrix. The depolarizer is a rough-surfaced retardation plate with a random function of position introducing random phase differences between the two orthogonal components of the electric vector. Under the assumption of Gaussian statistics with zero mean, the surface model for the depolarizer of the rough-surfaced retardation plate is obtained. The propagation of the modulated fields through any quadratic optical system is examined within the framework of the complex ABCD matrix theory to show how the degree of coherence and polarization of the beam changes on propagation, including propagation in free space. PMID:26831388

  6. 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

    2015-01-01

    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. PMID:26177896

  7. Conductivity Variation Observed by Polarization and Depolarization Current Measurements of High-Voltage Equipment Insulation System

    NASA Astrophysics Data System (ADS)

    Jamail, Nor Akmal Mohd; Piah, Mohamed Afendi Mohamed; Muhamad, Nor Asiah

    2012-09-01

    Nondestructive and time domain dielectric measurement techniques such as polarization and depolarization current (PDC) measurements have recently been widely used as a potential tool for determining high-voltage insulation conditions by analyzing the insulation conductivity. The variation in the conductivity of an insulator was found to depend on several parameters: the difference between the polarization and depolarization currents, geometric capacitance, and the relative permittivity of the insulation material. In this paper the conductivities of different types of oil-paper insulation material are presented. The insulation conductivities of several types of electrical apparatus were simulated using MATLAB. Conductivity insulation was found to be high at high polarizations and at the lowest depolarization current. It was also found to increase with increasing relative permittivity as well as with decreasing geometric capacitance of the insulating material.

  8. Light-induced depolarization of neurons using a modified Shaker K(+) channel and a molecular photoswitch.

    PubMed

    Chambers, James J; Banghart, Matthew R; Trauner, Dirk; Kramer, Richard H

    2006-11-01

    To trigger action potentials in neurons, most investigators use electrical or chemical stimulation. Here we describe an optical stimulation method based on semi-synthetic light-activated ion channels. These SPARK (synthetic photoisomerizable azobenzene-regulated K(+)) channels consist of a synthetic azobenzene-containing photoswitch and a genetically modified Shaker K(+) channel protein. SPARK channels with a wild-type selectivity filter elicit hyperpolarization and suppress action potential firing when activated by 390 nm light. A mutation in the pore converts the K(+)-selective Shaker channel into a nonselective cation channel. Activation of this modified channel with the same wavelength of light elicits depolarization of the membrane potential. Expression of these depolarizing SPARK channels in neurons allows light to rapidly and reversibly trigger action potential firing. Hence, hyper- and depolarizing SPARK channels provide a means for eliciting opposite effects on neurons in response to the same light stimulus. PMID:16870840

  9. Analysis of the Prevalence of and Factors Associated with Hearing Loss in Korean Adolescents

    PubMed Central

    Hong, Seok Min; Park, Il-Seok; Kim, Yong Bok; Hong, Seok Jin; Lee, Byungho

    2016-01-01

    Background Hearing loss can lead to a number of disabilities, subsequently reducing the quality of life. In general, hearing thresholds of adolescents are better than adults and the elderly. However, occasionally, adolescents acquire hearing loss for a number of reasons. In this study, our goal was to estimate the prevalence of hearing loss in the Korean population and to investigate the factors related to hearing thresholds in adolescents. Methods A cross-sectional study was conducted using data from the Korean National Health and Nutrition Examination Survey (KNHANES) between 2010 and 2012. We enrolled a total of 1,658 participants, ages 13 to 18 years. We investigated the prevalence of hearing loss and the factors associated with hearing thresholds at various frequencies (0.5, 1, 2, 3, 4, and 6 KHz). Results Weighted prevalence of unilateral and bilateral hearing loss in Korean adolescents was 2.2% and 0.4%, respectively. Weighted prevalence of hearing thresholds ≥ 20 dB at speech and high frequencies were 3.1% and 5.0%, respectively, for unilateral hearing loss and 0.7% and 1.9%, respectively, for bilateral. Age group, tympanometric data, and household income were significantly related to unilateral or bilateral hearing thresholds ≥ 20 dB at speech frequencies. Earphone use in noisy places was associated with bilateral hearing thresholds ≥ 20 dB at high frequencies. Conclusions The prevalence of hearing loss in Korean adolescents was 2.6% using the general standard threshold associated with hearing loss. However, the prevalence of hearing thresholds ≥ 20 dB for speech and high frequencies was much higher. The results from this study provide an estimate of hearing loss in adolescents and suggest the need for early detection and hearing preservation programs among adolescents. PMID:27513659

  10. Identification of nitrate leaching loss indicators through regression methods based on a meta-analysis of lysimeter studies.

    PubMed

    Boy-Roura, M; Cameron, K C; Di, H J

    2016-02-01

    This study presents a meta-analysis of 12 experiments that quantify nitrate-N leaching losses from grazed pasture systems in alluvial sedimentary soils in Canterbury (New Zealand). Mean measured nitrate-N leached (kg N/ha × 100 mm drainage) losses were 2.7 when no urine was applied, 8.4 at the urine rate of 300 kg N/ha, 9.8 at 500 kg N/ha, 24.5 at 700 kg N/ha and 51.4 at 1000 kg N/ha. Lismore soils presented significantly higher nitrate-N losses compared to Templeton soils. Moreover, a multiple linear regression (MLR) model was developed to determine the key factors that influence nitrate-N leaching and to predict nitrate-N leaching losses. The MLR analyses was calibrated and validated using 82 average values of nitrate-N leached and 48 explanatory variables representative of nitrogen inputs and outputs, transport, attenuation of nitrogen and farm management practices. The MLR model (R (2) = 0.81) showed that nitrate-N leaching losses were greater at higher urine application rates and when there was more drainage from rainfall and irrigation. On the other hand, nitrate leaching decreased when nitrification inhibitors (e.g. dicyandiamide (DCD)) were applied. Predicted nitrate-N leaching losses at the paddock scale were calculated using the MLR equation, and they varied largely depending on the urine application rate and urine patch coverage. PMID:26498804

  11. Scattering loss analysis and structure optimization of hollow-core photonic bandgap fiber

    NASA Astrophysics Data System (ADS)

    Song, Jingming; Wu, Rong; Sun, Kang; Xu, Xiaoliang

    2016-06-01

    Effects of core structure in 7 cell hollow-core photonic bandgap fibers (HC-PBGFs) on scattering loss are analyzed by means of investigating normalized interface field intensity. Fibers with different core wall thickness, core radius and rounding corner of air hole are simulated. Results show that with thick core wall and expanded core radius, scattering loss could be greatly reduced. The scattering loss of the HC-PBGFs in the wavelength range of 1.5-1.56 μm could be decreased by about 50 % of the present level with optimized core structure design.

  12. Chronic Graft Loss and Death in Patients With Post-Transplant Malignancy in Living Kidney Transplantation: A Competing Risk Analysis

    PubMed Central

    Salesi, Mahmoud; Rostami, Zohreh; Rahimi Foroushani, Abbas; Mehrazmay, Ali Reza; Mohammadi, Jamile; Einollahi, Behzad; Asgharian, Saeed; Eshraghian, Mohammad Reza

    2014-01-01

    Background: Malignancy is a common complication after renal transplantation. Death with functioning graft and chronic graft loss are two competing outcomes in patients with post-transplant malignancies. Objectives: The purpose of our study was to evaluate the risk factors associated with cumulative incidence of these two outcomes. Patients and Methods: Fine-Gray model was used for 266 cases with post-transplant malignancy in Iran. These patients were followed-up from the diagnosis until the date of last visit, chronic graft loss, or death, subsequently. Results: At the end of the study, as competing events, chronic graft loss and death with functioning graft were seen in 27 (10.2%) and 53 cases (19.9%), respectively, while 186 cases (69.9%) were accounted as censored. The incidence rate of death was approximately two-time of the incidence rate of chronic graft loss (8.6 vs. 4.4 per 100 person-years). In multivariate analysis, significant risk factors associated with cumulative incidence of death included age (P < 0.007, subhazard ratio (SHR) = 1.03), type of cancer (P < 0.0001), and response to treatment (P < 0.0001, SHR = 0.027). The significant risk factors associated with cumulative incidence of chronic graft loss were gender (P = 0.05, SHR = 0.37), treatment modality (P < 0.0001), and response to treatment (P = 0.048, SHR = 0.47). Conclusions: Using these factors, nephrologists may predict the occurrence of graft loss or death. If the probability of graft loss was higher, physicians can decrease the immunosuppressive medications dosage to decrease the incidence of graft loss. PMID:25032129

  13. Role of membrane depolarization and extracellular calcium in increased complement receptor expression during neutrophil (PMN) activation

    SciTech Connect

    Berger, M.; Wetzler, E.; Birx, D.L.

    1986-03-05

    During PMN activation the surface expression of receptors (R) for C3b and C3bi increases rapidly. This is necessary for optimal cell adhesion, migration, and phagocytosis. Following stimulation with fMLP or LTB-4, the increased expression of C3bR depends only on the Ca/sup + +/ released from intracellular stores and is not inhibited by 5mM EDTA, while the increase in C3biR also requires extracellular Ca/sup + +/. CR expression also increases when the PMN are depolarized with 140 mM K/sup +/, but with this stimulus, EDTA inhibits C3bR by 67% and C3biR 100%, suggesting that intracellular Ca/sup + +/ stores may not be released. Pertussis toxin caused dose-dependent inhibition of both CR responses to fMLP and also inhibited the increases in both CR induced by K/sup +/. Membrane depolarization (monitored by di-O-C5 fluorescence) due to fMLP was similarly inhibited by toxin but the depolarization due to K/sup +/ was not. The dose of phorbol myristate acetate that maximally increased CR expression, 0.1 ng/ml, did not depolarize the membrane. These results suggest that membrane depolarization is neither necessary nor sufficient for increased CR expression. A Ca/sup + +/ and GTP binding protein-dependent enzyme such as phospholipase C is necessary to the amplify initial signals generated either by release of Ca/sup + +/ stores or by opening voltage dependent Ca/sup + +/ channels following membrane depolarization.

  14. CO2 decreases membrane conductance and depolarizes neurons in the nucleus tractus solitarii.

    PubMed

    Dean, J B; Lawing, W L; Millhorn, D E

    1989-01-01

    To identify central sites of potential CO2/H+-chemoreceptive neurons, and the mechanism responsible for neuronal chemosensitivity, intracellular recordings were made in rat tissue slices in two cardiopulmonary-related regions (i.e., nucleus tractus solitarii, NTS; nucleus ambiguus, AMBc) during exposure to high CO2. When the NTS was explored slices were bisected and the ventral half discarded. Utilizing such "dorsal" medullary slices removed any impinging synaptic input from putative chemoreceptors in the ventrolateral medulla. In the NTS, CO2-induced changes in firing rate were associated with membrane depolarizations ranging from 2-25 mV (n = 15). In some cases increased e.p.s.p. activity was observed during CO2 exposure. The CO2-induced depolarization occurred concomitantly with an increased input resistance ranging from 19-23 M omega (n = 5). The lower membrane conductance during hypercapnia suggests that CO2-induced depolarization is due to a decreased outward potassium conductance. Unlike neurons in the NTS, AMBc neurons were not spontaneously active and were rarely depolarized by hypercapnia. Eleven of 12 cells tested were either hyperpolarized by or insensitive to CO2. Only 1 neuron in the AMBc was depolarized and it also showed an increased input resistance during CO2 exposure. Our findings suggest that CO2/H+-related stimuli decrease potassium conductance which depolarizes the cell and increases firing rate. Although our in vitro studies cannot guarantee the specific function of these cells, we believe they may be involved with brain pH homeostasis and cardiopulmonary regulation. PMID:2507342

  15. Characterization of the anandamide induced depolarization of guinea-pig isolated vagus nerve

    PubMed Central

    Kagaya, Manabu; Lamb, Jasmine; Robbins, Jon; Page, Clive P; Spina, Domenico

    2002-01-01

    There is considerable interest in elucidating potential endogenously derived agonists of the vanilloid receptor and the role of anandamide in this regard has received considerable attention. In the present study, we have used an electrophysiological technique to investigate the mechanism of activation of vanilloid receptors in an isolated vagal preparation. Both capsaicin and anandamide depolarized de-sheathed whole vagal nerve preparations that was antagonized by the VR1 antagonist, capsazepine (P<0.05) whilst this response was unaltered by the cannabinoid (CB1) selective antagonist SR141716A or the CB2 selective antagonist, SR144528, thereby ruling out a role for cannabinoid receptors in this response. The PKC activator, phorbol-12-myristate-13-acetate (PMA) augmented depolarization to both anandamide and capsaicin and this response was significantly inhibited with the PKC inhibitor, bisindolylmaleimide (BIM) (P<0.05). The role of lipoxygenase products in the depolarization to anandamide was investigated in the presence of the lipoxygenase inhibitor, 5,8,11-Eicosatriynoic acid (ETI). Depolarization to anandamide and arachidonic acid was significantly inhibited in the presence of ET1 (P<0.05). However, in the absence of calcium depolarization to anandamide was not inhibited by ETI. Using confocal microscopy we have demonstrated the presence of vanilloid receptors on both neuropeptide containing nerves and nerves that did not stain for sensory neuropeptides. These results demonstrate that anandamide evokes depolarization of guinea-pig vagus nerve, following activation of vanilloid receptors, a component of which involves the generation of lipoxygenase products. Furthermore, these receptors are distributed in both neuropeptide and non-neuropeptide containing nerves. PMID:12183329

  16. SNP Array Analysis Reveals Novel Genomic Abnormalities Including Copy Neutral Loss of Heterozygosity in Anaplastic Oligodendrogliomas

    PubMed Central

    Idbaih, Ahmed; Ducray, François; Dehais, Caroline; Courdy, Célia; Carpentier, Catherine; de Bernard, Simon; Uro-Coste, Emmanuelle; Mokhtari, Karima; Jouvet, Anne; Honnorat, Jérôme; Chinot, Olivier; Ramirez, Carole; Beauchesne, Patrick; Benouaich-Amiel, Alexandra; Godard, Joël; Eimer, Sandrine; Parker, Fabrice; Lechapt-Zalcman, Emmanuelle; Colin, Philippe; Loussouarn, Delphine; Faillot, Thierry; Dam-Hieu, Phong; Elouadhani-Hamdi, Selma; Bauchet, Luc; Langlois, Olivier; Le Guerinel, Caroline; Fontaine, Denys; Vauleon, Elodie; Menei, Philippe; Fotso, Marie Janette Motsuo; Desenclos, Christine; Verelle, Pierre; Ghiringhelli, François; Noel, Georges; Labrousse, François; Carpentier, Antoine; Dhermain, Frédéric; Delattre, Jean-Yves; Figarella-Branger, Dominique

    2012-01-01

    Anaplastic oligodendrogliomas (AOD) are rare glial tumors in adults with relative homogeneous clinical, radiological and histological features at the time of diagnosis but dramatically various clinical courses. Studies have identified several molecular abnormalities with clinical or biological relevance to AOD (e.g. t(1;19)(q10;p10), IDH1, IDH2, CIC and FUBP1 mutations). To better characterize the clinical and biological behavior of this tumor type, the creation of a national multicentric network, named “Prise en charge des OLigodendrogliomes Anaplasiques (POLA),” has been supported by the Institut National du Cancer (InCA). Newly diagnosed and centrally validated AOD patients and their related biological material (tumor and blood samples) were prospectively included in the POLA clinical database and tissue bank, respectively. At the molecular level, we have conducted a high-resolution single nucleotide polymorphism array analysis, which included 83 patients. Despite a careful central pathological review, AOD have been found to exhibit heterogeneous genomic features. A total of 82% of the tumors exhibited a 1p/19q-co-deletion, while 18% harbor a distinct chromosome pattern. Novel focal abnormalities, including homozygously deleted, amplified and disrupted regions, have been identified. Recurring copy neutral losses of heterozygosity (CNLOH) inducing the modulation of gene expression have also been discovered. CNLOH in the CDKN2A locus was associated with protein silencing in 1/3 of the cases. In addition, FUBP1 homozygous deletion was detected in one case suggesting a putative tumor suppressor role of FUBP1 in AOD. Our study showed that the genomic and pathological analyses of AOD are synergistic in detecting relevant clinical and biological subgroups of AOD. PMID:23071531

  17. Tooth loss and oral health-related quality of life: a systematic review and meta-analysis

    PubMed Central

    2010-01-01

    Background It is increasingly recognized that the impact of disease on quality of life should be taken into account when assessing health status. It is likely that tooth loss, in most cases being a consequence of oral diseases, affects Oral Health-Related Quality of Life (OHRQoL). The aim of the present study is to systematically review the literature and to analyse the relationship between the number and location of missing teeth and oral health-related quality of life (OHRQoL). It was hypothesized that tooth loss is associated with an impairment of OHRQoL. Secondly, it was hypothesized that location and distribution of remaining teeth play an important role in this. Methods Relevant databases were searched for papers in English, published from 1990 to July 2009 following a broad search strategy. Relevant papers were selected by two independent readers using predefined exclusion criteria, firstly on the basis of abstracts, secondly by assessing full-text papers. Selected studies were grouped on the basis of OHRQoL instruments used and assessed for feasibility for quantitative synthesis. Comparable outcomes were subjected to meta-analysis; remaining outcomes were subjected to a qualitative synthesis only. Results From a total of 924 references, 35 were eligible for synthesis (inter-reader agreement abstracts κ = 0.84 ± 0.03; full-texts: κ = 0.68 ± 0.06). Meta-analysis was feasible for 10 studies reporting on 13 different samples, resulting in 6 separate analyses. All studies showed that tooth loss is associated with unfavourable OHRQoL scores, independent of study location and OHRQoL instrument used. Qualitative synthesis showed that all 9 studies investigating a possible relationship between number of occluding pairs of teeth present and OHRQoL reported significant positive correlations. Five studies presented separate data regarding OHRQoL and location of tooth loss (anterior tooth loss vs. posterior tooth loss). Four of these reported highest impact for

  18. Nitrogen and phosphorus losses from agricultural systems in China: a meta-analysis.

    PubMed

    Cao, Di; Cao, Wenzhi; Fang, Jing; Cai, Longyan

    2014-08-30

    Studies worldwide have indicated that agricultural pollution is the main source of nitrogen and phosphorus (N and P) in surface waters. A systematic understanding of N and P sources and sinks in agricultural systems is important for selecting the appropriate remedial strategies to control nutrient losses and water pollution. Based on nationwide data and a long-term monitoring program in Southeast China, the nationwide spatial and temporal patterns of N and P losses and the relationships between such losses and N and P inputs and rainfall were analyzed. The results showed that the annual nutrient losses from agricultural systems in China strongly varied, and the N/P values ranged from 0.01 to 51.0, with a majority at approximately 0-20, and an arithmetic mean of 9.73; these values mostly overlap the suitable range of N/P (6-15) for red bloom algae. PMID:24934439

  19. Correlation of the interdental and the interradicular bone loss: A radiovisuographic analysis

    PubMed Central

    Grover, Vishakha; Malhotra, Ranjan; Kapoor, Anoop; Mankotia, Chahat Singh; Bither, Rupika

    2014-01-01

    Background: Presence of furcation involvement indicates advanced periodontitis, and a potentially less-favorable prognosis, for the affected tooth and its diagnosis has always been an enigma. The present study was carried out to measure and correlate the interdental and interradicular bone loss in patients suffering from periodontitis using radiovisuography (RVG) for the purpose of early furcation diagnosis. Materials and Methods: A total of 50 patients suffering from chronic generalized periodontitis and with furcation involvement in mandibular molars were selected. Under standardized conditions, RVGs were taken and the morphologic measurements defining the furcation areas were recorded and analyzed. Result: Interradicular bone loss of about 0.8 mm or more, was observed in the study subjects only when the bone loss at the interdental area was minimal of 3.7 mm. The correlation between the interradicular and the interdental bone loss was statistically highly significant (T-test, P < 0.001). A stronger correlation was observed in subjects above 40 years of age as compared with the younger subjects. There was not much difference in the degree of correlation between the interradicular and the interdental bone loss when compared in the context of gender. Conclusion: The very first millimeter of interradicular bone loss was seen when the interdental bone loss was around 4 mm. Therefore, to detect the earliest lesions of furcations, the interdental bone loss can be kept as an approximate guide for the comprehensive diagnosis and management of such sites/patients. The current investigation paves the path for future longitudinal studies with larger samples to ascertain these findings. PMID:25210264

  20. Analysis of audio-vestibular assessment in acute low-tone hearing loss.

    PubMed

    Im, Gi Jung; Kim, Sung Kyun; Choi, June; Song, Jae Jun; Chae, Sung Won; Jung, Hak Hyun

    2016-07-01

    Conclusion This study demonstrated excellent hearing recovery following the combined treatment of diuretic and oral steroid, and electrocochleography (ECoG) was significantly higher than normal side. This study reports characteristics of acute low-tone hearing loss (ALHL) that show the greater low-tone hearing loss, the higher ECoG, and excellent recovery, even-though low-tone hearing loss is worse, which can be different compared with sudden deafness. Objective To analyze ALHL without vertigo, this study compared the ALHL group with all patients exhibiting low-tone hearing loss and ear fullness. Hearing changes and vestibular functions were analyzed. Materials and methods ALHL was defined as a mean hearing loss of ≥ 30 dB at 125, 250, and 500 Hz, and ≤ 20 dB at 2, 4, and 8 kHz. From 156 cases of low-tone hearing loss of more than 10 dB without vertigo, 31 met the ALHL criteria and were subjected to audio-vestibular assessments including PTA, ECoG, vestibular evoked myogenic potential (VEMP) testing, and caloric testing. Results In ALHL, low-tone hearing loss was 42.7 ± 9.5 dB, and 83.9% of ALHL significantly recovered by more than 10 dB. The ECoG in ALHL was 0.334 ± 0.11 (higher than 0.25 ± 0.08 on the normal side) and ECoG abnormality was 35.5% (the greater low-tone hearing loss, the higher ECoG value). PMID:26963446

  1. The utility of monetary contingency contracts for weight loss: a systematic review and meta-analysis.

    PubMed

    Sykes-Muskett, Bianca J; Prestwich, Andrew; Lawton, Rebecca J; Armitage, Christopher J

    2015-01-01

    Financial incentives to improve health have received increasing attention, but are subject to ethical concerns. Monetary Contingency Contracts (MCCs), which require individuals to deposit money that is refunded contingent on reaching a goal, are a potential alternative strategy. This review evaluates systematically the evidence for weight loss-related MCCs. Randomised controlled trials testing the effect of weight loss-related MCCs were identified in online databases. Random-effects meta-analyses were used to calculate overall effect sizes for weight loss and participant retention. The association between MCC characteristics and weight loss/participant retention effects was calculated using meta-regression. There was a significant small-to-medium effect of MCCs on weight loss during treatment when one outlier study was removed. Group refunds, deposit not paid as lump sum, participants setting their own deposit size and additional behaviour change techniques were associated with greater weight loss during treatment. Post-treatment, there was no significant effect of MCCs on weight loss. There was a significant small-to-medium effect of MCCs on participant retention during treatment. Researcher-set deposits paid as one lump sum, refunds delivered on an all-or-nothing basis and refunds contingent on attendance at classes were associated with greater retention during treatment. Post-treatment, there was no significant effect of MCCs on participant retention. The results support the use of MCCs to promote weight loss and participant retention up to the point that the incentive is removed and identifies the conditions under which MCCs work best. PMID:25933128

  2. Silent loss and the clinical encounter: Parents’ and physicians’ experiences of stillbirth–a qualitative analysis

    PubMed Central

    2012-01-01

    Background In the United States, an estimated 70 stillbirths occur each day, on average 25,000 each year. Research into the prevalence and causes of stillbirth is ongoing, but meanwhile, many parents suffer this devastating loss, largely in silence, due to persistent stigma and taboo; and many health providers report feeling ill equipped to support grieving parents. Interventions to address bereavement after neonatal death are increasingly common in U.S. hospitals, and there is growing data on the nature of parent bereavement after a stillbirth. However, further research is needed to evaluate supportive interventions and to investigate the parent-clinician encounter during hospitalization following a stillbirth. Qualitative inquiry offers opportunities to better understand the lived experience of parents against the backdrop of clinicians’ beliefs, intentions, and well-meaning efforts to support grieving parents. Methods We present a secondary qualitative analysis of transcript data from 3 semi-structured focus groups conducted with parents who had experienced a stillbirth and delivered in a hospital, and 2 focus groups with obstetrician-gynecologists. Participants were drawn from the greater Seattle region in Washington State. We examine parents’ and physicians’ experiences and beliefs surrounding stillbirth during the clinical encounter using iterative discourse analysis. Results Women reported that the cheery, bustling environment of the labor and delivery setting was a painful place for parents who had had a stillbirth, and that the well-meaning attempts of physicians to offer comfort often had the opposite effect. Parents also reported that their grief is deeply felt but not socially recognized. While physicians recognized patients’ grief, they did not grasp its depth or duration. Physicians viewed stillbirth as an unexpected clinical tragedy, though several considered stillbirth less traumatic than the death of a neonate. In the months and years

  3. The application of biosensors for drip loss analysis and glycolytic potential evaluation.

    PubMed

    Przybylski, Wiesław; Sionek, Barbara; Jaworska, Danuta; Santé-Lhoutellier, Véronique

    2016-07-01

    The aim of this study was to evaluate the relationship between glucose and lactate measured by biosensors in drip loss (strip method) with muscle glycolytic potential and their compounds. On the samples taken from Longissimus dorsi of 24 pigs (pure Neckar hybrid line) the following meat quality traits were determined: pH at 24h, meat color according to CIE L(⁎)a(⁎)b(⁎) system and drip loss. The highest correlations were found between glucose in drip loss and glycogen (r=0.84) or glycolytic potential (r=0.81) in muscle. A significant positive relationship between lactate measured in muscle by enzymatic method and by biosensor in drip loss was established (r=0.76). Glycogen, glucose, lactate and glycolytic potential with meat quality traits as ultimate pH, lightness, b(⁎) value and drip loss were significantly related. Results of multiple regression between glucose as well as lactate measured in muscle drip loss with muscle glycolytic potential showed the possibility of its prediction (r=0.87 with Pα≤0.001). PMID:26930360

  4. Of broken bonds and bondage: an analysis of loss in the Slave Narrative Collection.

    PubMed

    Laurie, Anna; Neimeyer, Robert A

    2010-03-01

    Relatively few scholars have made use of the Slave Narrative Collection, a collection of more than 2,300 autobiographical narratives detailing the lives of people who had been born into slavery. Housed at the Library of Congress, the Collection was gathered during the 1930s under the direction of the Federal Writers Project. Research derived from the Collection thus far has dealt primarily with the experience of slavery as a whole. The present study focuses on loss as it was experienced by former slaves. This qualitative study used a grounded theory approach to analyze 48 narratives. Results culminated in a core category or central theme that for former slaves loss was both a cause and a consequence of dehumanization. Findings also suggested that people experienced loss as a result of witnessing or experiencing violence and of living in deprivation and fear. Other losses included losses of hope and identity. Losses associated with the pain and suffering of family members were hardest to bear. PMID:24479182

  5. Novel magnetic core materials impact modelling and analysis for minimization of RF heating loss

    NASA Astrophysics Data System (ADS)

    Ghosh, Bablu Kumar; Mohamad, Khairul Anuar; Saad, Ismail

    2016-02-01

    The eddy current that exists in RF transformer/inductor leads to generation of noise/heat in the circuit and ultimately reduces efficiency in RF system. Eddy current is generated in the magnetic core of the inductor/transformer largely determine the power loss for power transferring process. The losses for high-frequency magnetic components are complicated due to both the eddy current variation in magnetic core and copper windings reactance variation with frequency. Core materials permeability and permittivity are also related to variation of such losses those linked to the operating frequency. This paper will discuss mainly the selection of novel magnetic core materials for minimization of eddy power loss by using the approach of empirical equation and impedance plane simulation software TEDDY V1.2. By varying the operating frequency from 100 kHz to 1GHz and magnetic flux density from 0 to 2 Tesla, the eddy power loss is evaluated in our study. The Nano crystalline core material is found to be the best core material due to its low eddy power loss at low conductivity for optimum band of frequency application.

  6. Analysis and comparison for rotor eddy current losses of permanent magnet synchronous generator according to dc and ac load conditions

    NASA Astrophysics Data System (ADS)

    Jang, Seok-Myeong; Kim, Hyun-Kyu; Choi, Jang-Young; Ko, Kyoung-Jin

    2009-04-01

    This paper presents an analytical procedure for the calculation of the eddy current losses of permanent magnet synchronous generator (PMSG). The dc and ac loading effects on the eddy current is examined through the suggested analytical procedure that considers the radial and tangential flux density waveform through a phase current harmonic analysis. The corresponding test results are also presented to quantify and compare those loading effects on the eddy current. The results verified the suggested analytical procedures and show that the rotor eddy current losses for PMSG with the dc loads turned out to be more significant than those with the ac loads.

  7. Arrests, Recent Life Circumstances, and Recurrent Job Loss for At-Risk Young Men: An Event-History Analysis

    PubMed Central

    Wiesner, Margit; Capaldi, Deborah M.; Kim, Hyoun K.

    2009-01-01

    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, recent arrests, recent drug use, and recent being married/cohabitation. It is argued that long-term effects of criminal justice contact on employment outcomes should be understood in the context of (shared) prior risk factors and recent life circumstances. PMID:20383311

  8. On the basis of delayed depolarization and its role in repetitive firing of Rohon-Beard neurones in Xenopus tadpoles.

    PubMed Central

    Spitzer, N C

    1984-01-01

    A delayed depolarization following the impulse can be recorded intracellularly from mature Rohon-Beard neurones in the spinal cord of Xenopus tadpoles, in response both to brief intracellularly injected current pulses and to antidromic stimulation. Evidence is presented suggesting that this delayed depolarization is unlikely to be due to the action of a chemical synapse, activation of a voltage-dependent conductance in the cell body, increased extracellular potassium, or electrotonic coupling. Hyperpolarization of the cell body during antidromic stimulation eliminates the action potential normally generated there, and reveals an impulse arising at some distance along a neurite. When an action potential is produced in the cell body, its repolarizing phase sculpts a delayed depolarization from this impulse in the neurite. The depolarization is enhanced by pressure applied to the neurites near the cell body, presumably by reducing the distal spread of current, and yields multiple action potentials. Although long current pulses usually produce only a single spike, small quantities of La3+ enhance the size of the depolarization and cause repetitive firing. The relation of impulse frequency to injected current shows a non-linearity consistent with the summation of the delayed depolarization and the depolarization by the injected current. The non-linearity is eliminated upon removal of delayed depolarization by hyperpolarizing current pulses injected after each impulse. The enhancement of the depolarization by La3+ is not the only cause of repetitive firing; La3+ also produces an effective reduction in conductance for outward currents. This depolarization may play a role in the normal firing behaviour of Rohon-Beard neurones; when repetitive firing results naturally in response to long current pulses the delayed depolarization is observed to be large. Images Plate 1 PMID:6512703

  9. How to deal properly with a natural catastrophe database - analysis of flood losses

    NASA Astrophysics Data System (ADS)

    Kron, W.; Steuer, M.; Löw, P.; Wirtz, A.

    2012-03-01

    Global reinsurer Munich Re has been collecting data on losses from natural disasters for almost four decades. Together with EM-Dat and sigma, Munich Re's NatCatSERVICE database is currently one of three global databases of its kind, with its more than 30 000 datasets. Although the database was originally designed for reinsurance business purposes, it contains a host of additional information on catastrophic events. Data collection poses difficulties such as not knowing the exact extent of human and material losses, biased reporting by interest groups, including governments, changes over time due to new findings, etc. Loss quantities are often not separable into different causes, e.g., windstorm and flood losses during a hurricane, or windstorm, hail and flooding during a severe storm event. These difficulties should be kept in mind when database figures are analysed statistically, and the results have to be treated with due regard for the characteristics of the underlying data. Comparing events at different locations and on different dates can only be done using normalised data. For most analyses, and in particular trend analyses, socio-economic changes such as inflation or growth in population and values must be considered. Problems encountered when analysing trends are discussed using the example of floods and flood losses.

  10. Heat loss analysis of a 10 kA warm dielectric HTS DC cable

    NASA Astrophysics Data System (ADS)

    Dai, Shaotao; Xiao, Liye; Teng, Yuping; Song, Naihao; Gao, Zhiyuan; Zhu, Zhiqing; Liang, Xueming; Cao, Zhicheng; Zhang, Dong; Ma, Tao; Zhang, Hongen; Lin, Liangzhen

    2014-09-01

    A 10 kA/360 m warm-dielectric high-temperature superconducting direct current (DC) power cable system (10 kA cable), supported jointly the Chinese government and industrial enterprise, was developed and has been operating as a branch circuit to transmit power for a 320 kA aluminum electrolyzing production line for more than 10 months at an industrial plant in central China. Both the 10 kA cable and its supporting system of the cable system are introduced. The cryogenic system for the 10 kA cable adopts closed loop and the sub-cooled liquid nitrogen is forced to flow inside by a pump. The design of corrugated cryogenic envelope pipe is modularized and every independent module has two standardized joints, which makes it easy to integrate with the other pipes and the terminations. The heat loss sources and the structure including both the termination and the cryogenic envelope pipe of the 10 kA cable are discussed. The total heat loss of the 10 kA cable excluding the loss of cryogenic pipe for liquid nitrogen backward flowing is designed to be less than 1698 W at 10 kA, and the heat loss was compared and discussed with that of the aluminum bar. The field test and commissioning of the cable show that the 10 kA cable performs steadily and its heat loss is less than the expected value.

  11. Global Earthquake Casualties due to Secondary Effects: A Quantitative Analysis for Improving PAGER Losses

    USGS Publications Warehouse

    Wald, David J.

    2010-01-01

    This study presents a quantitative and geospatial description of global losses due to earthquake-induced secondary effects, including landslide, liquefaction, tsunami, and fire for events during the past 40 years. These processes are of great importance to the US Geological Survey’s (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER) system, which is currently being developed to deliver rapid earthquake impact and loss assessments following large/significant global earthquakes. An important question is how dominant are losses due to secondary effects (and under what conditions, and in which regions)? Thus, which of these effects should receive higher priority research efforts in order to enhance PAGER’s overall assessment of earthquakes losses and alerting for the likelihood of secondary impacts? We find that while 21.5% of fatal earthquakes have deaths due to secondary (non-shaking) causes, only rarely are secondary effects the main cause of fatalities. The recent 2004 Great Sumatra–Andaman Islands earthquake is a notable exception, with extraordinary losses due to tsunami. The potential for secondary hazards varies greatly, and systematically, due to regional geologic and geomorphic conditions. Based on our findings, we have built country-specific disclaimers for PAGER that address potential for each hazard (Earle et al., Proceedings of the 14th World Conference of the Earthquake Engineering, Beijing, China, 2008). We will now focus on ways to model casualties from secondary effects based on their relative importance as well as their general predictability.

  12. Global earthquake casualties due to secondary effects: A quantitative analysis for improving rapid loss analyses

    USGS Publications Warehouse

    Marano, K.D.; Wald, D.J.; Allen, T.I.

    2010-01-01

    This study presents a quantitative and geospatial description of global losses due to earthquake-induced secondary effects, including landslide, liquefaction, tsunami, and fire for events during the past 40 years. These processes are of great importance to the US Geological Survey's (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER) system, which is currently being developed to deliver rapid earthquake impact and loss assessments following large/significant global earthquakes. An important question is how dominant are losses due to secondary effects (and under what conditions, and in which regions)? Thus, which of these effects should receive higher priority research efforts in order to enhance PAGER's overall assessment of earthquakes losses and alerting for the likelihood of secondary impacts? We find that while 21.5% of fatal earthquakes have deaths due to secondary (non-shaking) causes, only rarely are secondary effects the main cause of fatalities. The recent 2004 Great Sumatra-Andaman Islands earthquake is a notable exception, with extraordinary losses due to tsunami. The potential for secondary hazards varies greatly, and systematically, due to regional geologic and geomorphic conditions. Based on our findings, we have built country-specific disclaimers for PAGER that address potential for each hazard (Earle et al., Proceedings of the 14th World Conference of the Earthquake Engineering, Beijing, China, 2008). We will now focus on ways to model casualties from secondary effects based on their relative importance as well as their general predictability. ?? Springer Science+Business Media B.V. 2009.

  13. Implementing BosonSampling with time-bin encoding: Analysis of loss, mode mismatch, and time jitter

    NASA Astrophysics Data System (ADS)

    Motes, Keith R.; Dowling, Jonathan P.; Gilchrist, Alexei; Rohde, Peter P.

    2015-11-01

    It was recently shown by Motes, Gilchrist, Dowling, and Rohde [Phys. Rev. Lett. 113, 120501 (2014), 10.1103/PhysRevLett.113.120501] that a time-bin encoded fiber-loop architecture can implement an arbitrary passive linear optics transformation. This was shown in the case of an ideal scheme whereby the architecture has no sources of error. In any realistic implementation, however, physical errors are present, which corrupt the output of the transformation. We investigate the dominant sources of error in this architecture—loss and mode mismatch—and consider how it affects the BosonSampling protocol, a key application for passive linear optics. For our loss analysis we consider two major components that contribute to loss—fiber and switches—and calculate how this affects the success probability and fidelity of the device. Interestingly, we find that errors due to loss are not uniform (unique to time-bin encoding), which asymmetrically biases the implemented unitary. Thus loss necessarily limits the class of unitaries that may be implemented, and therefore future implementations must prioritize minimizing loss rates if arbitrary unitaries are to be implemented. Our formalism for mode mismatch is generalized to account for various phenomenon that may cause mode mismatch, but we focus on two—errors in fiber-loop lengths and time jitter of the photon source. These results provide a guideline for how well future experimental implementations might perform in light of these error mechanisms.

  14. Integrative Analysis of Metabolomic, Proteomic and Genomic Data to Reveal Functional Pathways and Candidate Genes for Drip Loss in Pigs.

    PubMed

    Welzenbach, Julia; Neuhoff, Christiane; Heidt, Hanna; Cinar, Mehmet Ulas; Looft, Christian; Schellander, Karl; Tholen, Ernst; Große-Brinkhaus, Christine

    2016-01-01

    The aim of this study was to integrate multi omics data to characterize underlying functional pathways and candidate genes for drip loss in pigs. The consideration of different omics levels allows elucidating the black box of phenotype expression. Metabolite and protein profiling was applied in Musculus longissimus dorsi samples of 97 Duroc × Pietrain pigs. In total, 126 and 35 annotated metabolites and proteins were quantified, respectively. In addition, all animals were genotyped with the porcine 60 k Illumina beadchip. An enrichment analysis resulted in 10 pathways, amongst others, sphingolipid metabolism and glycolysis/gluconeogenesis, with significant influence on drip loss. Drip loss and 22 metabolic components were analyzed as intermediate phenotypes within a genome-wide association study (GWAS). We detected significantly associated genetic markers and candidate genes for drip loss and for most of the metabolic components. On chromosome 18, a region with promising candidate genes was identified based on SNPs associated with drip loss, the protein "phosphoglycerate mutase 2" and the metabolite glycine. We hypothesize that association studies based on intermediate phenotypes are able to provide comprehensive insights in the genetic variation of genes directly involved in the metabolism of performance traits. In this way, the analyses contribute to identify reliable candidate genes. PMID:27589727

  15. Calcium measurements with electron probe X-ray and electron energy loss analysis.

    PubMed Central

    LeFurgey, A; Ingram, P

    1990-01-01

    This paper presents a broad survey of the rationale for electron probe X-ray microanalysis (EPXMA) and the various methods for obtaining qualitative and quantitative information on the distribution and amount of elements, particularly calcium, in cryopreserved cells and tissues. Essential in an introductory consideration of microanalysis in biological cryosections is the physical basis for the instrumentation, fundamentals of X-ray spectrometry, and various analytical modes such as static probing and X-ray imaging. Some common artifacts are beam damage and contamination. Inherent pitfalls of energy dispersive X-ray systems include Si escape peaks, doublets, background, and detector calibration shifts. Quantitative calcium analysis of thin cryosections is carried out in real time using a multiple least squares fitting program on filtered X-ray spectra and normalizing the calcium peak to a portion of the continuum. Recent work includes the development of an X-ray imaging system where quantitative data can be retrieved off-line. The minimum detectable concentration of calcium in biological cryosections is approximately 300 mumole kg dry weight with a spatial resolution of approximately 100 A. The application of electron energy loss (EELS) techniques to the detection of calcium offers the potential for greater sensitivity and spatial resolution in measurement and imaging. Determination of mass thickness with EELS can facilitate accurate calculation of wet weight concentrations from frozen hydrated and freeze-dried specimens. Calcium has multiple effects on cell metabolism, membrane transport and permeability and, thus, on overall cell physiology or pathophysiology. Cells can be rapidly frozen for EPXMA during basal or altered functional conditions to delineate the location and amount of calcium within cells and the changes in location and concentration of cations or anions accompanying calcium redistribution. Recent experiments in our laboratory document that EPXMA in

  16. Optimization of biomass torrefaction conditions by the gain and loss method and regression model analysis.

    PubMed

    Lee, Soo Min; Lee, Jae-Won

    2014-11-01

    In this study, the optimal conditions for biomass torrefaction were determined by comparing the gain of energy content to the weight loss of biomass from the final products. Torrefaction experiments were performed at temperatures ranging from 220 to 280°C using 20-80min reaction times. Polynomial regression models ranging from the 1st to the 3rd order were used to determine a relationship between the severity factor (SF) and calorific value or weight loss. The intersection of two regression models for calorific value and weight loss was determined and assumed to be the optimized SF. The optimized SFs on each biomass ranged from 6.056 to 6.372. Optimized torrefaction conditions were determined at various reaction times of 15, 30, and 60min. The average optimized temperature was 248.55°C in the studied biomass when torrefaction was performed for 60min. PMID:25266685

  17. Rotor Losses in a Switched Reluctance Motor - Analysis and Reduction Methods

    NASA Astrophysics Data System (ADS)

    Schweighofer, B.; Recheis, M.; Fulmek, P.; Wegleiter, H.

    2013-01-01

    Due to the increasing hybridization and electrification of vehicles, flywheel energy storage devices are an important area of research. In automotive application besides the weight criteria, some additionally constrains, such as size, efficiency and especially cost have to be fulfilled. Therefore typically a compact design, in which the rotor of the needed electrical machine simultaneously acts as storage mass is chosen. Since the machine is running in vacuum and the rotor can dissipate its heat only by means of thermal radiation or through the bearings if conventional bearings are used, the rotor losses play a vital role. In this work the rotor losses of a switched reluctance machine are analyzed in detail and a method to reduce the rotor losses is proposed.

  18. A novel loss compensation technique analysis and design for 60 GHz CMOS SPDT switch

    NASA Astrophysics Data System (ADS)

    Zonghua, Zheng; Lingling, Sun; Jun, Liu; Shengzhou, Zhang

    2016-01-01

    A novel loss compensation technique for a series-shunt single-pole double-throw (SPDT) switch is presented operating in the 60 GHz. The feed-forward compensation network which is composed of an NMOS, a couple capacitance and a shunt inductance can reduce the impact of the feed forward capacitance to reduce the insertion loss and improve the isolation of the SPDT switch. The measured insertion loss and isolation characteristics of the switch somewhat deviating from the 60 GHz are analyzed revealing that the inaccuracy of the MOS model can greatly degrade the performance of the switch. The switch is implemented in TSMC 90-nm CMOS process and exhibits an isolation of above 27 dB at transmitter mode, and the insertion loss of 1.8-3 dB at 30-65 GHz by layout simulation. The measured insertion loss is 2.45 dB at 52 GHz and keeps < 4 dB at 30-64 GHz. The measured isolation is better than 25 dB at 30-64 GHz and the measured return loss is better than 10 dB at 30-65 GHz. A measured input 1 dB gain compression point of the switch is 13 dBm at 52 GHz and 15 dBm at 60 GHz. The simulated switching speed with rise time and fall time are 720 and 520 ps, respectively. The active chip size of the proposed switch is 0.5 × 0.95 mm2. Project supported by the National Natural Science Foundation of China (Nos. 61331006, 61372021).

  19. Self-directed interventions to promote weight loss: a systematic review and meta-analysis.

    PubMed

    Tang, Jason C H; Abraham, Charles; Greaves, Colin J; Nikolaou, Vasilis

    2016-09-01

    Many self-directed weight-loss interventions have been developed using a variety of delivery formats (e.g., internet and smartphone) and change techniques. Yet, little research has examined whether self-directed interventions can exclusively promote weight loss. MEDLINE, Embase, PsycINFO, CINAHL, and the Cochrane Library were systematically reviewed for randomised controlled trials evaluating self-directed interventions in relation to weight-loss outcomes in adults. Standardised mean differences (SMD) and 95% confidence intervals (CI) were calculated using a random effects model. Twenty-seven trials incorporating 36 comparisons met our inclusion criteria. Participants using self-directed interventions lost significantly more weight (MD = -1.56 kg, CI -2.25, -0.86 ranging from 0.6 to 5.3 kg) compared to those in the minimal intervention or no-treatment groups (3.1-month follow-up median). The majority of interventions were internet based (18 evaluations) and these were effective at 3 months (MD = -1.74 kg, CI -2.65, -0.82 ranging from 0.6 to 4.8 kg) (SMD = -0.48, 95% CI -0.72, -0.24, I(2) = 82%; p < .0001; 16 evaluations) and 6 months follow-up (MD = -2.71 kg, CI -4.03, -1.39 ranging from 2.2 to 5.3 kg) (SMD = -0.59, 95% CI -0.99, -0.19, I(2) = 76%; p = .004; 4 evaluations). Self-directed weight-loss interventions can generate modest weight loss for up to 6 months but may need to be supplemented by other interventions to achieve sustained and clinically meaningful weight loss. PMID:27091296

  20. Analysis of a small break loss-of-coolant accident of pressurized water reactor by APROS

    SciTech Connect

    Al-Falahi, A.; Haennine, M.; Porkholm, K.

    1995-09-01

    The purpose of this paper is to study the capability of APROS (Advanced PROcess Simulator) code to simulate the real plant thermal-hydraulic transient of a Small Break Loss-Of-Coolant Accident (SBLOCA) of Loss-Of-Fluid Test (LOFT) facility. The LOFT is a scaled model of a Pressurized Water Reactor (PWR). This work is a part of a larger validation of the APROS thermal-hydraulic models. The results of SBLOCA transient calculated by APROS showed a reasonable agreement with the measured data.

  1. Isoliquiritigenin induces apoptosis by depolarizing mitochondrial membranes in prostate cancer cells.

    PubMed

    Jung, Jae In; Lim, Soon Sung; Choi, Hyun Ju; Cho, Han Jin; Shin, Hyun-Kyung; Kim, Eun Ji; Chung, Won-Yoon; Park, Kwang-Kyun; Park, Jung Han Yoon

    2006-10-01

    Isoliquiritigenin (ISL), a simple chalcone derivative, 4,2',4'-trihydroxychalcone, found in licorice, shallot and bean sprouts, has been reported to have chemoprotective effects. To examine the effects of ISL on the growth of prostate cancer cells, we cultured MAT-LyLu (MLL) rat and DU145 human prostate cancer cells with various concentrations (0-20 micromol/L) of ISL. Treatment of the cells with increasing concentrations of ISL led to dose-dependent decreases in the viable cell numbers in both DU145 and MLL cells (P<.05). Hoechst 33258 dye staining of condensed nuclei and annexin V binding to surface phosphatidylserine revealed increased numbers of apoptotic cells after ISL treatment. Western blot analysis revealed that ISL increased the levels of membrane-bound Fas ligand (FasL), Fas, cleaved casapse-8, truncated Bid (tBid), Bax and Bad in DU145 cells (P<.05). Isoliquiritigenin increased the percentage of cells with depolarized mitochondrial membranes, in a concentration-dependent manner (P<.05). Isoliquiritigenin induced the release of cytochrome c and Smac/Diablo from the mitochondria into the cytoplasm (P<.05). Isoliquiritigenin dose-dependently increased the levels of cleaved caspase-9, caspase-7, caspase-3 and poly(ADP-ribose) polymerase (P<.05). The present results indicate that ISL inhibits prostate cancer cell growth by the induction of apoptosis, which is mediated through mitochondrial events, which are associated with an evident disruption of the mitochondrial membrane potential, and the release of cytochrome c and Smac/Diablo, and the activation of caspase-9. PMID:16517140

  2. Depolarization-induced release of amino acids from the vestibular nuclear complex.

    PubMed

    Godfrey, Donald A; Sun, Yizhe; Frisch, Christopher; Godfrey, Matthew A; Rubin, Allan M

    2012-04-01

    There is evidence from immunohistochemistry, quantitative microchemistry, and pharmacology for several amino acids as neurotransmitters in the vestibular nuclear complex (VNC), including glutamate, γ-aminobutyrate (GABA), and glycine. However, evidence from measurements of release has been limited. The purpose of this study was to measure depolarization-stimulated calcium-dependent release of amino acids from the VNC in brain slices. Coronal slices containing predominantly the VNC were prepared from rats and perfused with artificial cerebrospinal fluid (ACSF) in an interface chamber. Fluid was collected from the chamber just downstream from the VNC using a microsiphon. Depolarization was induced by 50 mM potassium in either control calcium and magnesium concentrations or reduced calcium and elevated magnesium. Amino acid concentrations in effluent fluid were measured by high performance liquid chromatography. Glutamate release increased fivefold during depolarization in control calcium concentration and twofold in low calcium/high magnesium. These same ratios were 6 and 1.5 for GABA, 2 and 1.3 for glycine, and 2 and 1.5 for aspartate. Differences between release in control and low calcium/high magnesium ACSF were statistically significant for glutamate, GABA, and glycine. Glutamine release decreased during and after depolarization, and taurine release slowly increased. No evidence for calcium-dependent release was found for serine, glutamine, alanine, threonine, arginine, taurine, or tyrosine. Our results support glutamate and GABA as major neurotransmitters in the VNC. They also support glycine as a neurotransmitter and some function for taurine. PMID:22147284

  3. Suppression of Ultracold Neutron Depolarization on Material Surfaces with Magnetic Holding Fields

    NASA Astrophysics Data System (ADS)

    Rios, Raymond

    2009-10-01

    Experiments involving polarized Ultracold Neutrons (UCN) for high precision measurements require the use of high Fermi potential materials with a low spin flip probability per bounce. Previous studies show that the spin flip probability for materials vary on the order of 10-3 to 10-6. In this study, the depolarization of UCN was measured within 1-m long, 2 3/4" diameter bare copper, electropolished copper, diamond-like carbon-coated copper, and stainless steel guide tubes as a function of the magnetic holding field. The UCN were trapped between a 6 Tesla solenoidal magnet and a copper plate. A series of Helmholtz coils produced a magnetic holding field over the length of the test guide at 10, 100, or 250 Gauss. The surface depolarization was observed to be suppressed at higher holding fields. These measurements will aid in the determination of an upper limit on depolarization of UCN in the UCNA beta asymmetry measurement at LANL and in understanding the mechanisms for depolarization in non-magnetic guides.

  4. Tranexamic Acid Reduces Hidden Blood Loss in Patients Undergoing Total Knee Arthroplasty: A Comparative Study and Meta-Analysis

    PubMed Central

    Huang, Guang-Ping; Jia, Xu-Feng; Xiang, Zhou; Ji, Yong; Wu, Guo-Yong; Tang, Yi; Li, Jian; Zhang, Jun

    2016-01-01

    Background To explore the efficacy of tranexamic acid (TXA) on reducing hidden blood loss (HBL) in total knee arthroplasty (TKA) by conducting a comparative study and meta-analysis. Material/Methods A total of 108 patients underwent TKA was equally distributed to experimental and control groups. The only difference between two groups was the administrations of 15 mg of TXA mixed in 100 mL normal saline for experimental group and 100 mL of normal saline for control group. The volumes of blood loss, red blood loss (RBL) were recorded, calculated and analyzed. Stata 12.0 software was applied for data analysis. Results The intraoperative and postoperative blood loss volume in experimental group were remarkably reduced compared with those in control group (intraoperative: 105.1±12.1 mL vs. 185.5±20.3 mL, P<0.001; postoperative: 220.7±16.8 mL vs. 290.5±22.4 mL, P<0.001). Accordingly, the control group had significantly higher transfusion rate than experimental group (3.7% vs.25.9%, P=0.001). Our results also found that both the measured and hidden RBL were obviously reduced in experimental group compared with control group (measured RBL: 96.9±11.8 mL vs. 135.2±13.5 mL, P<0.001; hidden RBL: 170.8±37.2 mL vs. 364.2±41.5 mL, P<0.001). Furthermore, meta-analysis confirmed that TXA can notably decrease HBL (SMD=2.68, 95%CI=1.55~3.80, P<0.001). Conclusions TXA can significantly reduce the intraoperative and postoperative blood loss and HBL, therefore decreasing the transfusion need in TKA. PMID:26961597

  5. Kramers-Kronig analysis of reflection electron-energy-loss spectra measured with a cylindrical mirror analyzer

    NASA Astrophysics Data System (ADS)

    Ohno, Youichi

    1989-04-01

    We have discussed a valence-electron energy-loss spectrum measured in reflection geometry using a cylindrical mirror analyzer (CMA) and derived the angular distribution of inelastic scattering, the momentum transfer, and the differential cross section per unit energy. If a critical inelastic-scattering angle is smaller than the angular aperture of the analyzer, the differential cross section no longer depends on momentum transfer. The reflection electron-energy-loss spectroscopy (REELS) spectra of MoS2 and graphite have been measured and the Kramers-Kronig analysis has been applied. The results are compared with those of the composite energy-loss function calculated from the energy-loss functions perpendicular and parallel to the c axis. It has been shown that the Kramers-Kronig analysis is still valid for the REELS spectra at higher incident energies than 500 eV and that the derived optical constants consist approximately of 80% of the perpendicular component and 20% of the parallel component.

  6. Spike after-depolarization and burst generation in adult rat hippocampal CA1 pyramidal cells.

    PubMed Central

    Jensen, M S; Azouz, R; Yaari, Y

    1996-01-01

    1. Intracellular recordings in adult rat hippocampal slices were used to investigate the properties and origins of intrinsically generated bursts in the somata of CA1 pyramidal cells (PCs). The CA1 PCs were classified as either non-bursters or bursters according to the firing patterns evoked by intrasomatically applied long ( > or = 100 ms) depolarizing current pulses. Non-bursters generated stimulus-graded trains of independent action potentials, whereas bursters generated clusters of three or more closely spaced spikes riding on a distinct depolarizing envelope. 2. In all PCs fast spike repolarization was incomplete and ended at a potential approximately 10 mV more positive than resting potential. Solitary spikes were followed by a distinct after-depolarizing potential (ADP) lasting 20-40 ms. The ADP in most non-bursters declined monotonically to baseline ('passive' ADP), whereas in most bursters it remained steady or even re-depolarized before declining to baseline ('active' ADP). 3. Active, but not passive, ADPs were associated with an apparent increase in input conductance. They were maximal in amplitude when the spike was evoked from resting potential and were reduced by mild depolarization or hyperpolarization (+/- 2 mV). 4. Evoked and spontaneous burst firing was sensitive to small changes in membrane potential. In most cases maximal bursts were generated at resting potential and were curtailed by small depolarizations or hyperpolarizations (+/- 5 mV). 5. Bursts comprising clusters of spikelets ('d-spikes') were observed in 12% of the bursters. Some of the d-spikes attained threshold for triggering full somatic spikes. Gradually hyperpolarizing these neurones blocked somatic spikes before blocking d-spikes, suggesting that the latter are generated at more remote sites. 6. The data suggest that active ADPs and intrinsic bursts in the somata of adult CA1 PCs are generated by a slow, voltage-gated inward current. Bursts arise in neurones in which this current

  7. Sensitivity and uncertainty analysis for the annual P loss estimator (APLE) model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Models are often used to predict phosphorus (P) loss from agricultural fields. While it is commonly recognized that there are inherent uncertainties with model predictions, limited studies have addressed model prediction uncertainty. In this study we assess the effect of model input error on predict...

  8. Sensitivity and uncertainty analysis for a field-scale P loss model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Models are often used to predict phosphorus (P) loss from agricultural fields. While it is commonly recognized that there are inherent uncertainties with model predictions, limited studies have addressed model prediction uncertainty. In this study we assess the effect of model input error on predict...

  9. Modal analysis of thin cylindrical shells with cardboard liners and estimation of loss factors

    NASA Astrophysics Data System (ADS)

    Koruk, Hasan; Dreyer, Jason T.; Singh, Rajendra

    2014-04-01

    Cardboard liners are often installed within automotive drive shafts to reduce radiated noise over a certain frequency range. However, the precise mechanisms that yield noise attenuation are not well understood. To overcome this void, a thin shell (under free boundaries) with different cardboard liner thicknesses is examined using analytical, computational and experimental methods. First, an experimental procedure is introduced to determine the modal behavior of a cylindrical shell with a cardboard liner. Then, acoustic and vibration frequency response functions are measured in acoustic free field, and natural frequencies and the loss factors of structures are determined. The adverse effects caused by closely spaced modes during the identification of modal loss factors are minimized, and variations in measured natural frequencies and loss factors are explored. Material properties of a cardboard liner are also determined using an elastic plate treated with a thin liner. Finally, the natural frequencies and modal loss factors of a cylindrical shell with cardboard liners are estimated using analytical and computational methods, and the sources of damping mechanisms are identified. The proposed procedure can be effectively used to model a damped cylindrical shell (with a cardboard liner) to predict its vibro-acoustic response.

  10. Depolarization of mitochondria in neurons promotes activation of nitric oxide synthase and generation of nitric oxide.

    PubMed

    Katakam, Prasad V G; Dutta, Somhrita; Sure, Venkata N; Grovenburg, Samuel M; Gordon, Angellica O; Peterson, Nicholas R; Rutkai, Ibolya; Busija, David W

    2016-05-01

    The diverse signaling events following mitochondrial depolarization in neurons are not clear. We examined for the first time the effects of mitochondrial depolarization on mitochondrial function, intracellular calcium, neuronal nitric oxide synthase (nNOS) activation, and nitric oxide (NO) production in cultured neurons and perivascular nerves. Cultured rat primary cortical neurons were studied on 7-10 days in vitro, and endothelium-denuded cerebral arteries of adult Sprague-Dawley rats were studied ex vivo. Diazoxide and BMS-191095 (BMS), activators of mitochondrial KATP channels, depolarized mitochondria in cultured neurons and increased cytosolic calcium levels. However, the mitochondrial oxygen consumption rate was unaffected by mitochondrial depolarization. In addition, diazoxide and BMS not only increased the nNOS phosphorylation at positive regulatory serine 1417 but also decreased nNOS phosphorylation at negative regulatory serine 847. Furthermore, diazoxide and BMS increased NO production in cultured neurons measured with both fluorescence microscopy and electron spin resonance spectroscopy, which was sensitive to inhibition by the selective nNOS inhibitor 7-nitroindazole (7-NI). Diazoxide also protected cultured neurons against oxygen-glucose deprivation, which was blocked by NOS inhibition and rescued by NO donors. Finally, BMS induced vasodilation of endothelium denuded, freshly isolated cerebral arteries that was diminished by 7-NI and tetrodotoxin. Thus pharmacological depolarization of mitochondria promotes activation of nNOS leading to generation of NO in cultured neurons and endothelium-denuded arteries. Mitochondrial-induced NO production leads to increased cellular resistance to lethal stress by cultured neurons and to vasodilation of denuded cerebral arteries. PMID:26945078

  11. Dual depolarization responses generated within the same lateral septal neurons by TRPC4-containing channels

    PubMed Central

    Tian, Jinbin; Thakur, Dhananjay P.; Lu, Yungang; Zhu, Yingmin; Freichel, Marc; Flockerzi, Veit

    2013-01-01

    In the central nervous system, canonical transient receptor potential (TRPC) channels have been implicated in mediating neuronal excitation induced by stimulating metabotropic receptors, including group 1 metabotropic glutamate receptors (mGluRs). Lateral septal (LS) neurons express high levels of TRPC4 and group I mGluRs. However, to what extent native TRPC4-containing channels (TRPC4-cc) are activated as well as the impact of different levels of TRPC4-cc activation on neuronal excitability remain elusive. Here, we report that stimulating LS neurons with group I mGluR agonist, (S)-3,5-DHPG, causes either an immediate increase in firing rate or an initial burst followed by a pause of firing, which can be correlated with below-threshold-depolarization (BTD) or above-threshold-plateau-depolarization (ATPD), respectively, in whole-cell recordings. The early phase of BTD and the entire ATPD are completely absent in neurons from TRPC4−/− mice. Moreover, in the same LS neurons, BTD can be converted to ATPD at more depolarized potentials or with a brief current injection, suggesting that BTD and ATPD may represent partial and full activations of TRPC4-cc, respectively. We show that coincident mGluR stimulation and depolarization is required to evoke strong TRPC4-cc current, and Na+ and Ca2+ influx, together with dynamic changes of intracellular Ca2+, are essential for ATPD induction. Our results suggest that TRPC4-cc integrates metabotropic receptor stimulation with intracellular Ca2+ signals to generate two interconvertible depolarization responses to affect excitability of LS neurons in distinct fashions. PMID:24121765

  12. Unsuspected early neuronal loss in scrapie-infected mice revealed by morphometric analysis.

    PubMed

    Scott, J R; Jeffrey, M; Halliday, W G

    1994-06-01

    This study was undertaken to determine to what extent neuronal loss is a feature of scrapie pathology, using an experimental model in which infectivity and subsequent vacuolar lesions are well characterized but in which neuronal loss has not been previously identified. Intraocular infection with ME7 scrapie directs infection through the major projections of the optic nerve, which include the dorsal lateral geniculate nucleus (dLGN) on the contralateral side to the infected eye. Infectivity can be detected in the dLGN at 77 days post-infection and vacuolar lesions are first seen around halfway through the incubation period of 240 days. Morphometric assessment of neuron number in the dLGN was made on gallocyanin stained semi-serial sections from 5 infected and 5 normal brain-injected controls at 4 fifty-day intervals during the incubation period, and on clinically terminal mice. The number of neurons in the dLGN of the infected mice decreased steadily from around 20,000 at 50 days post-infection to under 2,000 in the terminal group. The loss was delayed in the ipsilateral dLGN, although terminal counts were the same for both sides. The onset of neuronal loss was coincident with initial vacuolar changes, and neuronal numbers were inversely proportional to the severity of vacuolation. It is concluded that scrapie infection causes a progressive neuronal loss that can be identified some 30-80 days after infectivity can be detected in the dLGN, long before the onset of clinical disease. PMID:8030955

  13. Analysis of Germline Stem Cell Differentiation Following Loss of GLP-1 Notch Activity in Caenorhabditis elegans

    PubMed Central

    Fox, Paul M.; Schedl, Tim

    2015-01-01

    Stem cells generate the differentiated progeny cells of adult tissues. Stem cells in the Caenorhabditis elegans hermaphrodite germline are maintained within a proliferative zone of ∼230 cells, ∼20 cell diameters in length, through GLP-1 Notch signaling. The distal tip cell caps the germline and supplies GLP-1-activating ligand, and the distal-most germ cells that occupy this niche are likely self-renewing stem cells with active GLP-1 signaling. As germ cells are displaced from the niche, GLP-1 activity likely decreases, yet mitotically cycling germ cells are found throughout the proliferative zone prior to overt meiotic differentiation. Following loss of GLP-1 activity, it remains unclear whether stem cells undergo transit-amplifying (TA) divisions or more directly enter meiosis. To distinguish between these possibilities we employed a temperature-sensitive (ts) glp-1 mutant to manipulate GLP-1 activity. We characterized proliferative zone dynamics in glp-1(ts) mutants at permissive temperature and then analyzed the kinetics of meiotic entry of proliferative zone cells after loss of GLP-1. We found that entry of proliferative zone cells into meiosis following loss of GLP-1 activity is largely synchronous and independent of their distal-proximal position. Furthermore, the majority of cells complete only a single mitotic division before entering meiosis, independent of their distal-proximal position. We conclude that germ cells do not undergo TA divisions following loss of GLP-1 activity. We present a model for the dynamics of the proliferative zone that utilizes cell cycle rate and proliferative zone size and output and incorporates the more direct meiotic differentiation of germ cells following loss of GLP-1 activity. PMID:26158953

  14. Modeling and analysis of the unprotected loss-of-flow accident in the Clinch River Breeder Reactor

    SciTech Connect

    Morris, E.E.; Dunn, F.E.; Simms, R.; Gruber, E.E.

    1985-01-01

    The influence of fission-gas-driven fuel compaction on the energetics resulting from a loss-of-flow accident was estimated with the aid of the SAS3D accident analysis code. The analysis was carried out as part of the Clinch River Breeder Reactor licensing process. The TREAT tests L6, L7, and R8 were analyzed to assist in the modeling of fuel motion and the effects of plenum fission-gas release on coolant and clad dynamics. Special, conservative modeling was introduced to evaluate the effect of fission-gas pressure on the motion of the upper fuel pin segment following disruption. For the nominal sodium-void worth, fission-gas-driven fuel compaction did not adversely affect the outcome of the transient. When uncertainties in the sodium-void worth were considered, however, it was found that if fuel compaction occurs, loss-of-flow driven transient overpower phenomenology could not be precluded.

  15. Electrochemical performance investigations on the hydrogen depolarized CO2 concentrator

    NASA Technical Reports Server (NTRS)

    Aylward, J. R.

    1976-01-01

    An extensive investigation of anode and cathode polarization in complete cells and half cells was conducted to determine the factors affecting HDC electrode polarization and the nature of this polarization. Matrix-electrolyte-electrode interactions and cell electrolyte composition were also investigated. The electrodes were found to have normal performance capabilities. The HDC anode polarization characteristics were correlated with a theoretical kinetic analysis; and, except for some quantitative details, a rather complete understanding of the causes for HDC electrode polarization was formulated. One of the important finding resulting from the kinetic analysis was that platinum appears to catalyze the decomposition of carbonic acid to carbon dioxide and water. It was concluded that the abnormal voltage performance of the One Man ARS HDC cells was caused by insufficient cell electrolyte volume under normal operating conditions due to deficiencies in the reservoir to cell interfacing.

  16. Tropical cyclone losses in the USA and the impact of climate change - A trend analysis based on data from a new approach to adjusting storm losses

    SciTech Connect

    Schmidt, Silvio; Hoeppe, Peter

    2009-11-15

    Economic losses caused by tropical cyclones have increased dramatically. Historical changes in losses are a result of meteorological factors (changes in the incidence of severe cyclones, whether due to natural climate variability or as a result of human activity) and socio-economic factors (increased prosperity and a greater tendency for people to settle in exposed areas). This paper aims to isolate the socio-economic effects and ascertain the potential impact of climate change on this trend. Storm losses for the period 1950-2005 have been adjusted to the value of capital stock in 2005 so that any remaining trend cannot be ascribed to socio-economic developments. For this, we introduce a new approach to adjusting losses based on the change in capital stock at risk. Storm losses are mainly determined by the intensity of the storm and the material assets, such as property and infrastructure, located in the region affected. We therefore adjust the losses to exclude increases in the capital stock of the affected region. No trend is found for the period 1950-2005 as a whole. In the period 1971-2005, since the beginning of a trend towards increased intense cyclone activity, losses excluding socio-economic effects show an annual increase of 4% per annum. This increase must therefore be at least due to the impact of natural climate variability but, more likely than not, also due to anthropogenic forcings.

  17. Preliminary Analysis on Linac Oscillation Data LI05-19 and Wake Field Energy Loss in FACET Commissioning 2012

    SciTech Connect

    Sun, Yipeng; /SLAC

    2012-07-23

    In this note, preliminary analysis on linac ocsillation data in FACET linac LI05-09 plus LI11-19 is presented. Several quadrupoles are identified to possibly have different strength, compared with their designed strength in the MAD optics model. The beam energy loss due to longitudinal wake fields in the S-band linac is also analytically calculated, also by LITRACK numerical simulations.

  18. Evidence for two mechanisms of depolarization associated with alpha 1-adrenoceptor activation in the rat anococcygeus muscle.

    PubMed

    Byrne, N G; Large, W A

    1985-11-01

    Membrane potential responses in the rat isolated anococcygeus to bath-applied noradrenaline and field stimulation have been investigated by use of intracellular microelectrode and combined extracellular electrical and mechanical (sucrose gap) recording techniques. Intracellular recordings were made usually from tissues immobilized with hypertonic Krebs solution. Bath-application of noradrenaline produced depolarizations which consisted of two components; an initial 'fast' phase which peaked within 1-2 s and which was followed by a 'slow' sustained depolarization. Both components were concentration-dependent. Noradrenaline could also evoke oscillations in membrane potential which, unlike the 'fast' component of depolarization, were prevented by conditioning hyperpolarization of the membrane and were evoked by direct membrane depolarization with externally applied current pulses. Thus, the oscillations are voltage-dependent phenomena. Replacement of the external NaCl of the Krebs solution with an equimolar amount of Na benzenesulphonate abolished the noradrenaline-evoked 'fast' depolarization while the 'slow' phase was unaffected. This suggests that two mechanisms of depolarization are activated in this muscle by the bath-application of noradrenaline. The adrenergic excitatory junction potential was also abolished in Na benzenesulphonate. Prazosin reduced both the 'fast' and 'slow' components of depolarization produced by noradrenaline indicating their mediation by alpha 1-adrenoceptors. The membrane potential (-29 mV) at the maximum amplitude of the 'fast' depolarization was similar to the equilibrium potential (-27 mV) for the depolarization evoked by ionophoretically applied noradrenaline and which was obtained by extrapolation from the relationship between amplitude of the ionophoretic response and membrane potential displacement in the partition chamber. These results suggest that the 'fast' depolarization and the ionophoretic response are due to an increased

  19. Increased fruit and vegetable intake has no discernible effect on weight loss: a systematic review and meta-analysis1234

    PubMed Central

    Kaiser, Kathryn A; Brown, Andrew W; Bohan Brown, Michelle M; Shikany, James M; Mattes, Richard D; Allison, David B

    2014-01-01

    Background: A common dietary recommendation for weight loss, especially in lay public outlets, is to eat more fruit and vegetables (F/Vs). Without a compensatory reduction in total energy intake, significant weight loss would be unlikely. Objective: We aimed to synthesize the best available evidence on the effectiveness of the general recommendation to eat more F/Vs for weight loss or the prevention of weight gain. Design: We searched multiple databases for human randomized controlled trials that evaluated the effect of increased F/V intake on body weight. Inclusion criteria were as follows: ≥15 subjects/ treatment arm, ≥8-wk intervention, a stated primary or secondary outcome of body weight, the stated goal of the intervention was weight or fat loss or the prevention of weight or fat gain, and food intake provided or prescribed was of a variety of F/Vs that remained minimally processed. Results: Two studies met all criteria; 5 other studies met all criteria but one. The primary analysis indicated an effect size of weight change (outcome of interest) from baseline [standardized mean difference (SMD) for studies that met all criteria] of −0.16 (95% CI: −0.78, 0.46) (P = 0.60). The SMD for 7 studies that met all or most criteria was 0.04 (95% CI: −0.10, 0.17) (P = 0.62). Conclusions: Studies to date do not support the proposition that recommendations to increase F/V intake or the home delivery or provision of F/Vs will cause weight loss. On the basis of the current evidence, recommending increased F/V consumption to treat or prevent obesity without explicitly combining this approach with efforts to reduce intake of other energy sources is unwarranted. This systematic review and meta-analysis was registered at http://www.crd.york.ac.uk/PROSPERO/ as CRD42013004688 PMID:24965308

  20. Analysis of Thermal Losses for a Variety of Single-Junction Photovoltaic Cells: An Interesting Means of Thermoelectric Heat Recovery

    NASA Astrophysics Data System (ADS)

    Lorenzi, Bruno; Acciarri, Maurizio; Narducci, Dario

    2015-06-01

    Exploitation of solar energy conversion has become a fundamental aspect of satisfying a growing demand for energy. Thus, improvement of the efficiency of conversion in photovoltaic (PV) devices is highly desirable to further promote this source. Because it is well known that the most relevant efficiency constraint, especially for single-junction solar cells, is unused heat within the device, hybrid thermo-photovoltaic systems seem promising . Among several hybrid solutions proposed in the literature, coupling of thermoelectric and PV devices seems one of the most interesting. Taking full advantage of this technology requires proper definition and analysis of the thermal losses occurring in PV cells. In this communication we propose a novel analysis of such losses, decoupling source-dependent and absorber-dependent losses. This analysis enables an evaluation of the actual recoverable amount of energy, depending on the absorber used in the PV cell. It shows that for incoming solar irradiation of , and depending on the choice of material, the maximum available thermal power ranges from (for single-crystal silicon) to (for amorphous silicon).

  1. Ozone Loss In The Inner Vortex During Jan-mar 2000 By Multifractal Analysis of Er-2 Data

    NASA Astrophysics Data System (ADS)

    Tuck, A. F.; Hovde, S. J.; Richard, E. C.; Fahey, D. W.; Gao, R. S.

    Multifractal analysis has been used on ozone, wind speed and temperature measurements taken during straight and level flight legs in the inner vortex (defined as having wind speed less than 30 ms -1) to obtain the scaling exponents H1, C1 and ? which respectively characterize persistence, sparseness of the mean and degree of fractality. We use the clear temporal trends in H1 and ? for ozone to relate the scaling to the temporal evolution of methane and ozone on isentropic surfaces near 437 K potential temp erature. It is then possible to seoarate the adiabatic exchange and radiative cooling contributions to the methane trends, and by comparing with a published analysis [Richard et al., GRL, 28, 2197-2200, 2001] which establishes the ozone loss at constant tracer mixing ratio, we use the time dependence of the ozone scaling exponents to derive the actual ozone loss when the tracer decreases on an isentropic surface. We conclude that the inner vortex ozone loss is being diluted by dynamical dispersion at about half the rate at which the chemistry is causing it, 46 ppbv versus 23 ppbv d-1. Structure function analysis of total and gas phase NOy data suggests that low values of H1 seen in late January are imprinted via the chemistry on to the ozone, and that the cause is small scale variability in the degree of denitrification, which by mid-Marchis counteracted by the persistence induced by the smoothly varying, large scale insolation field.

  2. Virtual water trade and time scales for loss of water sustainability: A comparative regional analysis

    NASA Astrophysics Data System (ADS)

    Goswami, Prashant; Nishad, Shiv Narayan

    2015-03-01

    Assessment and policy design for sustainability in primary resources like arable land and water need to adopt long-term perspective; even small but persistent effects like net export of water may influence sustainability through irreversible losses. With growing consumption, this virtual water trade has become an important element in the water sustainability of a nation. We estimate and contrast the virtual (embedded) water trades of two populous nations, India and China, to present certain quantitative measures and time scales. Estimates show that export of embedded water alone can lead to loss of water sustainability. With the current rate of net export of water (embedded) in the end products, India is poised to lose its entire available water in less than 1000 years; much shorter time scales are implied in terms of water for production. The two cases contrast and exemplify sustainable and non-sustainable virtual water trade in long term perspective.

  3. Virtual water trade and time scales for loss of water sustainability: a comparative regional analysis.

    PubMed

    Goswami, Prashant; Nishad, Shiv Narayan

    2015-01-01

    Assessment and policy design for sustainability in primary resources like arable land and water need to adopt long-term perspective; even small but persistent effects like net export of water may influence sustainability through irreversible losses. With growing consumption, this virtual water trade has become an important element in the water sustainability of a nation. We estimate and contrast the virtual (embedded) water trades of two populous nations, India and China, to present certain quantitative measures and time scales. Estimates show that export of embedded water alone can lead to loss of water sustainability. With the current rate of net export of water (embedded) in the end products, India is poised to lose its entire available water in less than 1000 years; much shorter time scales are implied in terms of water for production. The two cases contrast and exemplify sustainable and non-sustainable virtual water trade in long term perspective. PMID:25790964

  4. Analysis of two dimensional composite surface grating structures with applications to low loss microacoustic resonators

    NASA Astrophysics Data System (ADS)

    Yantchev, Ventsislav; Plessky, Victor

    2013-08-01

    2D composite grating building blocks with hexagonal symmetry are proposed and analyzed as efficient reflectors and transducers in the design of low loss surface acoustic wave (SAW) resonators. Eigen-frequency and frequency response finite element analyses are used to study the propagation and excitation characteristics of SAWs in the 2D composite structures. The proposed structures have the advantage of being compatible with the planar SAW technology, while introducing design principles reminiscent to the semiconductor devices. More specifically, the frequency bandgap characteristics of the various resonator building blocks can be adjusted so that losses related to the SAW diffraction, impedance mismatch, and parasitic SAW radiation from the electrical contacts can be suppressed. Three distinct types SAW resonant topologies employing 2D gratings are deduced from the analytical results.

  5. Simulation analysis for effects of bone loss on acceleration tolerance of human lumbar vertebra

    NASA Astrophysics Data System (ADS)

    Ma, Honglei; Zhang, Feng; Zhu, Yu; Xiao, Yanhua; Wazir, Abrar

    2014-02-01

    The purpose of the present study was to analyze and predict the changes in acceleration tolerance of human vertebra as a result of bone loss caused by long-term space flight. A human L3-L4 vertebra FEM model was constructed, in which the cancellous bone was separated, and surrounding ligaments were also taken into account. The simulation results demonstrated that bone loss has more of an effect on the acceleration tolerance in x-direction. The results serve to aid in the creation of new acceleration tolerance standards, ensuring astronauts return home safely after long-term space flight. This study shows that more attention should be focused on the bone degradation of crew members and to create new protective designs for space capsules in the future.

  6. Virtual water trade and time scales for loss of water sustainability: A comparative regional analysis

    PubMed Central

    Goswami, Prashant; Nishad, Shiv Narayan

    2015-01-01

    Assessment and policy design for sustainability in primary resources like arable land and water need to adopt long-term perspective; even small but persistent effects like net export of water may influence sustainability through irreversible losses. With growing consumption, this virtual water trade has become an important element in the water sustainability of a nation. We estimate and contrast the virtual (embedded) water trades of two populous nations, India and China, to present certain quantitative measures and time scales. Estimates show that export of embedded water alone can lead to loss of water sustainability. With the current rate of net export of water (embedded) in the end products, India is poised to lose its entire available water in less than 1000 years; much shorter time scales are implied in terms of water for production. The two cases contrast and exemplify sustainable and non-sustainable virtual water trade in long term perspective. PMID:25790964

  7. ANALYSIS OF HIGH FIELD NON-LINEAR LOSSES ON SRF SURFACES DUE TO SPECIFIC TOPOGRAPHIC ROUGHNESS

    SciTech Connect

    Chen Xu,Charles Reece,Michael Kelley

    2012-07-01

    The high-field performance of SRF cavities will eventually be limited by the realization of fundamental material limits, whether it is Hc1 or Hsh, or some derivative thereof, at which the superconductivity is lost. Before reaching this fundamental field limit at the macro level, it must be encountered at localized, perhaps microscopic, sites of field enhancement due to local topography. If such sites are small enough, they may produce thermally stabilized normal-conducting regions which contribute non-linear losses when viewed from the macro resonant field perspective, and thus produce degradation in Q0. We have undertaken a calculation of local surface magnetic field enhancement from specific fine topographic structure by conformal mapping method and numerically. A solution of the resulting normal conducting volume has been derived and the corresponding RF Ohmic loss simulated.

  8. Drainage investment and wetland loss: an analysis of the national resources inventory data

    USGS Publications Warehouse

    Douglas, Aaron J.; Johnson, Richard L.

    1994-01-01

    The United States Soil Conservation Service (SCS) conducts a survey for the purpose of establishing an agricultural land use database. This survey is called the National Resources Inventory (NRI) database. The complex NRI land classification system, in conjunction with the quantitative information gathered by the survey, has numerous applications. The current paper uses the wetland area data gathered by the NRI in 1982 and 1987 to examine empirically the factors that generate wetland loss in the United States. The cross-section regression models listed here use the quantity of wetlands, the stock of drainage capital, the realty value of farmland and drainage costs to explain most of the cross-state variation in wetland loss rates. Wetlands preservation efforts by federal agencies assume that pecuniary economic factors play a decisive role in wetland drainage. The empirical models tested in the present paper validate this assumption.

  9. Comparative analysis reveals loss of the appetite-regulating peptide hormone ghrelin in falcons.

    PubMed

    Seim, Inge; Jeffery, Penny L; Herington, Adrian C; Chopin, Lisa K

    2015-05-15

    Ghrelin and leptin are key peripherally secreted appetite-regulating hormones in vertebrates. Here we consider the ghrelin gene (GHRL) of birds (class Aves), where it has been reported that ghrelin inhibits rather than augments feeding. Thirty-one bird species were compared, revealing that most species harbour a functional copy of GHRL and the coding region for its derived peptides ghrelin and obestatin. We provide evidence for loss of GHRL in saker and peregrine falcons, and this is likely to result from the insertion of an ERVK retrotransposon in intron 0. We hypothesise that the loss of anorexigenic ghrelin is a predatory adaptation that results in increased food-seeking behaviour and feeding in falcons. PMID:25500363

  10. Thermoacoustic Analysis of Displacer Gap Loss in a Low Temperature Stirling Cooler

    NASA Astrophysics Data System (ADS)

    Kotsubo, Vincent; Swift, Gregory

    2006-04-01

    Thermoacoustic theory is applied to oscillating flow in a parallel-plate gap with finite and unequal heat capacities on the two bounding walls, and with relative movement of one wall with respect to the other. The motivation is to understand the behavior of displacer gap losses at low temperatures in a Stirling cooler. Equations for the oscillating temperature and enthalpy flux down the gap and down the moving solid as a function of pressure amplitude, flow, temperatures, wall velocity, and material properties are derived. General expressions, along with results illustrating the behavior of the solutions, are presented. The primary result is that losses may increase significantly below 25 K, due to vanishing wall heat capacities and reduced thermal penetration depth in the helium gas.

  11. Loss of DHR sequences at Browns Ferry Unit One - accident-sequence analysis

    SciTech Connect

    Cook, D.H.; Grene, S.R.; Harrington, R.M.; Hodge, S.A.

    1983-05-01

    This study describes the predicted response of Unit One at the Browns Ferry Nuclear Plant to a postulated loss of decay heat removal (DHR) capability following scram from full power with the power conversion system unavailable. In accident sequences without DHR capability, the residual heat removal (RHR) system functions of pressure suppression pool cooling and reactor vessel shutdown cooling are unavailable. Consequently, all decay heat energy is stored in the pressure suppression pool with a concomitant increase in pool temperature and primary containment pressure. With the assumption that DHR capability is not regained during the lengthy course of this accident sequence, the containment ultimately fails by overpressurization. Although unlikely, this catastrophic failure might lead to loss of the ability to inject cooling water into the reactor vessel, causing subsequent core uncovery and meltdown. The timing of these events and the effective mitigating actions that might be taken by the operator are discussed in this report.

  12. Vibro-acoustic response and sound transmission loss analysis of functionally graded plates

    NASA Astrophysics Data System (ADS)

    Chandra, N.; Raja, S.; Nagendra Gopal, K. V.

    2014-10-01

    This paper presents analytical studies on the vibro-acoustic and sound transmission loss characteristics of functionally graded material (FGM) plates using a simple first-order shear deformation theory. The material properties of the plate are assumed to vary according to power law distribution of the constituent materials in terms of volume fraction. The sound radiation due to sinusoidally varying point load, uniformly distributed load and obliquely incident sound wave is computed by solving the Rayleigh integral with a primitive numerical scheme. Displacement, velocity, acceleration, radiated sound power level, radiated sound pressure level and radiation efficiency of FGM plate for varying power law index are examined. The sound transmission loss of the FGM plate for several incidence angles and varying power law index is studied in detail. It has been found that, for the plate being considered, the sound power level increases monotonically with increase in power law index at lower frequency range (0-500 Hz) and a non-monotonic trend is appeared towards higher frequencies for both point and distributed force excitations. Increased vibration and acoustic response is observed for ceramic-rich FGM plate at higher frequency band; whereas a similar trend is seen for metal-rich FGM plate at lower frequency band. The dBA values are found to be decreasing with increase in power law index. The radiation efficiency of ceramic-rich FGM plate is noticed to be higher than that of metal and metal-rich FGM plates. The transmission loss below the first resonance frequency is high for ceramic-rich FGM plate and low for metal-rich FGM plate and further depends on the specific material property. The study has found that increased transmission loss can be achieved at higher frequencies with metal-rich FGM plates.

  13. Finite element analysis of current flowing patterns and AC loss in the multifilament strand

    NASA Astrophysics Data System (ADS)

    Ta, Wurui; Li, Yingxu; Gao, Yuanwen

    2013-12-01

    Intrinsic current flow and field distribution scheme under the imposed low current injection and the applied weak field is meaningful to interpret Ic degradation and AC loss in a strand that performs as a normal composite conductor. A 2D finite element (FE) transport model is built in COMSOL to identify the various transverse resistance components and reveal the interrelation among them. Then the transverse resistivity components are taken as the basic electrical components in a 3D composite strand model. The 3D model follows the realistic trajectories of twisted filaments in strand composite and experimental material properties. To address the potential/current map in the stationary transport, the FE model is thoroughly analyzed for the short-sample and long-sample strand, imposed by two in-plane steady current injections and a potential boundary condition at one strand end with the other end grounded, respectively. The results show that the short-sample longitudinal current is uniform with little resistivity loss, and flows from the positive source and converges to the negative one in the cross section with different paths and current proportions between filaments and matrix. However, for the long-sample, there is a serious reduction in electric potential along the strand axis and the currents mostly concentrate on filaments. The time-varying problem is also implemented by computing AC loss induced by a relatively far-away alternating line current. It is discussed where appropriate that the effect of the twist pitch and contact resistivity on the pattern and magnitude of the current flow and AC loss.

  14. [Analysis of the causes of loss of tolerance to standard G-loads by fighter pilots].

    PubMed

    Sinopal'nikov, V I; Donin, K M; Boltikov, A N; Pugachev, I V; Migachev, S D

    2003-01-01

    Analytical treatment has been given to causes for the loss of tolerance to radial accelerations by fighter pilots subjected to clinical tests during flight medical certification in recent years. The diagnostic necessity of implementation of additional tests by this cohort of pilots has been demonstrated and methods to improve pilots' cardiovascular adaptability to g-loads during the inpatient medical examination have been proposed. PMID:14503193

  15. Analysis of unscrammed loss of flow and heat sink for PRISM with GEM

    SciTech Connect

    Slovik, G.C.; Van Tuyle, G.J.; Kennett, R.J. )

    1991-01-01

    The US Department of Energy is sponsoring an advanced liquid-metal reactor design by General Electric Company (GE) called PRISM. The intent is to design a reactor with passively safe responses to many operational and severe accidents. PRISM is under review at the US Nuclear Regulatory Commission for licensability with Brookhaven National Laboratory providing technical assistance. Recently, the PRISM design has been modified to include three gas expansion modules (GEMs) on its core periphery. The GEMs were added to quickly reduce the power (by inserting negative reactivity) during loss-of-flow events to curtail peak fuel and clad temperatures predicted in the previous design. The GEM prototypes have been tested at the Fast Flux Test Facility. The significance of the GEMs in PRISM is discussed in this paper through the evaluation of the unprotected loss of flow (ULOF) and loss of heat sink using the SSC code. It has been demonstrated in the past that SSC predicts results similar to GE and other liquid-metal reactor codes.

  16. Loss and gain signals in broadband stimulated-Raman spectra: Theoretical analysis

    NASA Astrophysics Data System (ADS)

    Harbola, Upendra; Umapathy, Siva; Mukamel, Shaul

    2013-07-01

    Stimulated optical signals obtained by subjecting the system to a narrow band and a broadband pulse show both gain and loss Raman features at the red and blue side of the narrow beam, respectively. Recently observed temperature-dependent asymmetry in these features [Mallick , J. Raman Spectrosc.JRSPAF0377-048610.1002/jrs.2996 42, 1883 (2011); Dang , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.107.043001 107, 043001 (2011)] has been attributed to the Stokes and anti-Stokes components of the third-order susceptibility, χ(3). By treating the setup as a steady state of an open system coupled to four quantum radiation field modes, we show that Stokes and anti-Stokes processes contribute to both the loss and gain resonances. χ(3) predicts loss and gain signals with equal intensity for electronically off-resonant excitation. Some asymmetry may exist for resonant excitation. However, this is unrelated to the Stokes vs anti-Stokes processes. Any observed temperature-dependent asymmetry must thus originate from effects lying outside the χ(3) regime.

  17. Analysis of short circuit current loss in rear emitter crystalline Si solar cell

    NASA Astrophysics Data System (ADS)

    Watahiki, Tatsuro; Kobayashi, Yumiko; Morioka, Takayuki; Nishimura, Shinya; Niinobe, Daisuke; Nishimura, Kunihiko; Tokioka, Hidetada; Yamamuka, Mikio

    2016-05-01

    Short circuit current (Jsc) loss in rear emitter crystalline Si solar cell is analyzed in detail by a 2D device simulation and compared with the experimental results. There is a significant loss in Jsc for the rear emitter n-Si solar cell with an n-type doped front surface field (FSF) when the base substrate resistivity is low. It is due to an increase in recombination in the FSF region led by a less barrier height for minority carriers with a lower substrate resistivity. The barrier height less than 0.1 eV causes large loss in Jsc. To achieve higher Jsc for the cells with FSF, the control of the doping concentration in FSF, the substrate thickness, and the barrier height for the minority carriers are important. A rear emitter heterojunction Si solar cell with an amorphous Si passivation layer shows no substrate resistivity dependence on Jsc since an amorphous Si possess a higher barrier height and a long bulk lifetime of more than a few milliseconds.

  18. Analysis of the Loss in Heat and Acid Resistance during Germination of Spores of Bacillus Species

    PubMed Central

    Luu, Stephanie

    2014-01-01

    A major event in the nutrient germination of spores of Bacillus species is release of the spores' large depot of dipicolinic acid (DPA). This event is preceded by both commitment, in which spores continue through germination even if germinants are removed, and loss of spore heat resistance. The latter event is puzzling, since spore heat resistance is due largely to core water content, which does not change until DPA is released during germination. We now find that for spores of two Bacillus species, the early loss in heat resistance during germination is most likely due to release of committed spores' DPA at temperatures not lethal for dormant spores. Loss in spore acid resistance during germination also paralleled commitment and was also associated with the release of DPA from committed spores at acid concentrations not lethal for dormant spores. These observations plus previous findings that DPA release during germination is preceded by a significant release of spore core cations suggest that there is a significant change in spore inner membrane permeability at commitment. Presumably, this altered membrane cannot retain DPA during heat or acid treatments innocuous for dormant spores, resulting in DPA-less spores that are rapidly killed. PMID:24563034

  19. Energy loss process analysis for radiation degradation and immediate recovery of amorphous silicon alloy solar cells

    NASA Astrophysics Data System (ADS)

    Sato, Shin-ichiro; Beernink, Kevin; Ohshima, Takeshi

    2015-06-01

    Performance degradation of a-Si/a-SiGe/a-SiGe triple-junction solar cells due to irradiation of silicon ions, electrons, and protons are investigated using an in-situ current-voltage measurement system. The performance recovery immediately after irradiation is also investigated. Significant recovery is always observed independent of radiation species and temperature. It is shown that the characteristic time, which is obtained by analyzing the short-circuit current annealing behavior, is an important parameter for practical applications in space. In addition, the radiation degradation mechanism is discussed by analyzing the energy loss process of incident particles (ionizing energy loss: IEL, and non-ionizing energy loss: NIEL) and their relative damage factors. It is determined that ionizing dose is the primarily parameter for electron degradation whereas displacement damage dose is the primarily parameter for proton degradation. This is because the ratio of NIEL to IEL in the case of electrons is small enough to be ignored the damage due to NIEL although the defect creation ratio of NIEL is much larger than that of IEL in the cases of both protons and electrons. The impact of “radiation quality effect” has to be considered to understand the degradation due to Si ion irradiation.

  20. General analytical approach for sound transmission loss analysis through a thick metamaterial plate

    SciTech Connect

    Oudich, Mourad; Zhou, Xiaoming; Badreddine Assouar, M.

    2014-11-21

    We report theoretically and numerically on the sound transmission loss performance through a thick plate-type acoustic metamaterial made of spring-mass resonators attached to the surface of a homogeneous elastic plate. Two general analytical approaches based on plane wave expansion were developed to calculate both the sound transmission loss through the metamaterial plate (thick and thin) and its band structure. The first one can be applied to thick plate systems to study the sound transmission for any normal or oblique incident sound pressure. The second approach gives the metamaterial dispersion behavior to describe the vibrational motions of the plate, which helps to understand the physics behind sound radiation through air by the structure. Computed results show that high sound transmission loss up to 72 dB at 2 kHz is reached with a thick metamaterial plate while only 23 dB can be obtained for a simple homogeneous plate with the same thickness. Such plate-type acoustic metamaterial can be a very effective solution for high performance sound insulation and structural vibration shielding in the very low-frequency range.

  1. Factors associated with grief and depression following the loss of a child: a multivariate analysis.

    PubMed

    Harper, Mairi; O'Connor, Rory C; O'Carroll, Ronan E

    2014-01-01

    The present study aims to explore the factors which are associated with grief and depression outcomes in a group of bereaved parents in the first few years following the loss of a child. Sixty-four participants were recruited from bereavement support organisations, between two and 59 months post loss, mean 30 months (SD = 15). They completed a questionnaire packet which comprised standard instruments measuring grief, depression, coping styles, continuing bonds and optimism/pessimism, as well as a number of specific bereavement-related questions. Univariate analyses were conducted to establish which factors were associated with grief and depression. Those which were statistically significant were then entered into multivariate analyses to establish their relative importance. High levels of avoidance and depression and lower levels of cognitive restructuring (benefit finding) were associated with higher grief symptoms, whereas higher levels of avoidance and alcohol/substance use were associated with higher depression symptoms. The present study highlights the relative importance of different coping strategies adopted by this group of bereaved parents, compared to the relative unimportance of circumstances around the loss, e.g. sudden or violent death. The use of alcohol and other substances by bereaved parents requires urgent attention as a potentially life-threatening maladaptive coping strategy. The call for further research into risk factors for bereaved parents is emphasised. PMID:23802736

  2. CFD analysis on control of secondary losses in STME LOX turbines with endwall fences

    NASA Technical Reports Server (NTRS)

    Chyu, Mingking K.

    1992-01-01

    The rotor blade in the newly designed LOX turbine for the future Space Transportation Main Engine (STME) has a severe flow turning angle, nearly 160 degrees. The estimated secondary loss in the rotor alone accounts for nearly 50 percent of the total loss over the entire stage. To reduce such a loss, one of the potential methods is to use fences attached on the turbine endwall (hub). As a prelude to examining the effects of endwall fence with actual STME turbine configuration, the present study focuses on similar issues with a different, but more generic, geometry - a rectangular duct with a 160-degree bend. The duct cross-section has a 2-to-1 aspect ratio and the radii of curvature for the inner and outer wall are 0.25 and 1.25 times the duct width, respectively. The present emphasis lies in examining the effects of various fence-length extending along the streamwise direction. The flowfield is numerically simulated using the FDNS code developed earlier by Wang and Chen. The FDNS code is a pressure based, finite-difference, Navier-Stokes equations solver.

  3. Teeth loss, teeth brushing and esophageal carcinoma: a systematic review and meta-analysis

    PubMed Central

    Chen, Hui; Nie, Shuping; Zhu, Yuhui; Lu, Ming

    2015-01-01

    Esophageal carcinoma (EC) is a serious malignancy, and its epidemiologic etiology is not fully explained. We performed this review to investigate the association between teeth loss and teeth brushing and the risk of EC. A systematic search was conducted to identify all relevant studies. The Q test and I2 statistic were used to examine between-study heterogeneity. Pooled odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were considered by fixed or random effects models. Furthermore, we conducted subgroup analyses based on study design, the studies’ geographic regions and case type of origin. Modified Egger linear regression test was used to estimate publication bias. Ten articles were included. Pooled analyses indicated that teeth loss was associated with an increased risk of EC for Asians (OR, 1.52; 95% CI: 1.30, 1.78), and high frequency of teeth brushing was associated with a lower incidence of EC (OR, 0.62; 95%CI: 0.43, 0.89). Subgroup analyses showed consistent results and no publication bias existed. Teeth loss and teeth brushing play potential roles in the progressing of EC. People should take care of their oral health in daily life. And large well-designed researches are needed to fully describe the association between teeth health and EC risk. PMID:26462879

  4. Loss and spinflip probabilities for ultracold neutrons interacting with diamondlike carbon and beryllium surfaces

    NASA Astrophysics Data System (ADS)

    Atchison, F.; Bryś, T.; Daum, M.; Fierlinger, P.; Geltenbort, P.; Henneck, R.; Heule, S.; Kasprzak, M.; Kirch, K.; Pichlmaier, A.; Plonka, C.; Straumann, U.; Wermelinger, C.; Zsigmond, G.

    2007-10-01

    The storage of ultracold neutrons (UCN) in a combined magnetic, gravitational, and material trap is described. Wall materials investigated were diamondlike carbon (DLC) coatings on solid and flexible foil substrates as well as beryllium coatings on solid substrates. The loss coefficient per wall collision, η, and the depolarization probability β were measured simultaneously as a function of temperature (from 70 to 400 K) and energy (from 30 to 80 neV). The results at 70 K are η=(0.7±0.1)×10-4,β=(15.4±1.0)×10-6 for DLC on polyethyleneterephtalate (PET) foil and η=(1.7±0.1)×10-4,β=(0.7±0.3)×10-6 for DLC on aluminum foil. At room temperature the loss coefficients are larger by a factor of about 2 whereas the depolarization probabilities are found to be independent of temperature. The corresponding values for Be at room temperature are η~5×10-4,β~10×10-6. The DLC results for β and for the temperature-dependent part of the loss coefficient, ηT, are interpreted in terms of incoherent scattering by hydrogen. The hydrogen admixture was measured independently by elastic recoil detection analysis to be about 1×1016 atoms/cm2. The data do not support the hypothesis of hydrogen being chemically bound within the top layers of the DLC. Using two different models with a thin waterlike film on top of the substrate we obtain consistency between the temperature-dependent loss contribution and the measured hydrogen contamination.

  5. Analysis of Mass Loss of a Polymeric Composite under Space Radiations

    NASA Astrophysics Data System (ADS)

    Khasanshin, Rashid

    2016-07-01

    Polymeric materials find ever-widening application in space technique. This is tied with the simplicity of producing the polymeric-based composites with the predetermined set of properties. However, these materials in space become the sources of volatile products that increase density of spacecraft outer atmosphere that undermines on serviceability of the on-board equipment. Therefore, study of mass loss of spacecraft materials in service conditions is a vital task. Polymeric composites are often used as thermal control coatings (TCC), which are subjected to maximum radiation exposure in service. It is known that irradiation of a PC is accompanied by intense gas formation but evolution of volatile products (VP) through the material-vacuum surface is limited by diffusion. Well-developed surface together with little thickness of a TCC film facilitate migration of radiolysis products to free coating surface. In this case outgassing and destruction of material augment permeability of the film, accelerate migration processes and make them easier. This work is devoted to studying action of separate (electron, proton, and electromagnetic), paired, and the whole set of radiations on mass loss of a pattern material in vacuum. The primary focus was on studying and interpretation of synergistic effects appearing in the course of mass loss of the pattern materials EKOM-1 and EKOM-2 polymeric composites, the widely used spacecraft TCC. Irradiation was made by 20-50-keV electrons and 20-keV protons and electromagnetic radiation in vacuum chamber of the UV-1/2 test facility. It was found that parameters characterizing the synergistic effects of mass loss of the material for fixed conditions of electron-proton and combined radiations are the functions of irradiation time. To interpret the experimental data, a physical-mathematical model of mass loss of polymeric materials in vacuum was proposed. The obtained data can be explained by diffusion fluxes associated with the gradient of

  6. Mobile Phone Apps to Promote Weight Loss and Increase Physical Activity: A Systematic Review and Meta-Analysis

    PubMed Central

    Ferré-Grau, Carme; Montaña-Carreras, Xavier

    2015-01-01

    Background To our knowledge, no meta-analysis to date has assessed the efficacy of mobile phone apps to promote weight loss and increase physical activity. Objective To perform a systematic review and meta-analysis of studies to compare the efficacy of mobile phone apps compared with other approaches to promote weight loss and increase physical activity. Methods We conducted a systematic review and meta-analysis of relevant studies identified by a search of PubMed, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Scopus from their inception through to August 2015. Two members of the study team (EG-F, GF-M) independently screened studies for inclusion criteria and extracted data. We included all controlled studies that assessed a mobile phone app intervention with weight-related health measures (ie, body weight, body mass index, or waist circumference) or physical activity outcomes. Net change estimates comparing the intervention group with the control group were pooled across studies using random-effects models. Results We included 12 articles in this systematic review and meta-analysis. Compared with the control group, use of a mobile phone app was associated with significant changes in body weight (kg) and body mass index (kg/m2) of -1.04 kg (95% CI -1.75 to -0.34; I2 = 41%) and -0.43 kg/m2 (95% CI -0.74 to -0.13; I2 = 50%), respectively. Moreover, a nonsignificant difference in physical activity was observed between the two groups (standardized mean difference 0.40, 95% CI -0.07 to 0.87; I2 = 93%). These findings were remarkably robust in the sensitivity analysis. No publication bias was shown. Conclusions Evidence from this study shows that mobile phone app-based interventions may be useful tools for weight loss. PMID:26554314

  7. Dynamic changes of depolarizing GABA in a computational model of epileptogenic brain: Insight for Dravet syndrome.

    PubMed

    Kurbatova, P; Wendling, F; Kaminska, A; Rosati, A; Nabbout, R; Guerrini, R; Dulac, O; Pons, G; Cornu, C; Nony, P; Chiron, C; Benquet, P

    2016-09-01

    Abnormal reemergence of depolarizing GABAA current during postnatal brain maturation may play a major role in paediatric epilepsies, Dravet syndrome (DS) being among the most severe. To study the impact of depolarizing GABA onto distinct patterns of EEG activity, we extended a neural mass model as follows: one sub-population of pyramidal cells was added as well as two sub-populations of interacting interneurons, perisomatic-projecting interneurons (basket-like) with fast synaptic kinetics GABAA (fast, I1) and dendritic-projecting interneurons with slow synaptic kinetics GABAA (slow, I2). Basket-like cells were interconnected to reproduce mutual inhibition mechanisms (I1➔I1). The firing rate of interneurons was adapted to mimic the genetic alteration of voltage gated sodium channels found in DS patients, SCN1A(+/-). We implemented the "dynamic depolarizing GABAA" mediated post-synaptic potential in the model, as some studies reported that the chloride reversal potential can switch from negative to more positive value depending on interneuron activity. The "shunting inhibition" promoted by GABAA receptor activation was also implemented. We found that increasing the proportion of depolarizing GABAA mediated IPSP (I1➔I1 and I1➔P) only (i.e., other parameters left unchanged) was sufficient to sequentially switch the EEG activity from background to (1) interictal isolated polymorphic epileptic spikes, (2) fast onset activity, (3) seizure like activity and (4) seizure termination. The interictal and ictal EEG patterns observed in 4 DS patients were reproduced by the model via tuning the amount of depolarizing GABAA postsynaptic potential. Finally, we implemented the modes of action of benzodiazepines and stiripentol, two drugs recommended in DS. Both drugs blocked seizure-like activity, partially and dose-dependently when applied separately, completely and with a synergic effect when combined, as has been observed in DS patients. This computational modeling study

  8. Research in depolarization of particles in Tibetan Plateau and coastal area by lidar

    NASA Astrophysics Data System (ADS)

    Dai, Guangyao; Wu, Songhua; Song, Xiaoquan; Qin, Shengguang; Liu, Bingyi; Liu, Jintao; Zhang, Kailin; Zhang, Wei

    2014-11-01

    Vertical profiles of the linear particle depolarization ratio p δ of cloud and aerosol in the Tibet Plateau were measured during the Tibetan Plateau atmospheric expedition experiment campaign with water vapor, cloud and aerosol lidar system, which is capable of depolarization ratio measurement. The atmospheric comprehensive observations were performed during July of 2013 at Litang (30.03°N,100.28°E), which is 3949 meters above the mean sea level, Sichuan province, China. It was the first time to detect and obtain the Tibetan Plateau cloud and aerosol lidar depolarization profiles to our knowledge. After completing the plateau experiment campaign, the lidar system measured the atmosphere above coastal area in Qingdao (36.165°N,120.4956°E). In this year, we continued to participate in the plateau experiment campaign in Nagchu (31.5°N,92.05°E), which is 4600 meters above the mean sea level, The Tibet Autonomous Region from 1st, July to 1st, September. Since particle size, shape and refractive index have an impact on linear particle depolarization ratio, one can classify the aerosol types and cloud phase in turn in the Tibetan Plateau and Qingdao area using linear particle depolarization ratio data. Generally, two calibration methods were applied: comparison of the lidar measurement data and CALIPSO simultaneous data method and half-wave plate ±45°switch method. In this paper we applied the comparison calibration method. The correlation coefficient between lidar measurement data and CALIPSO data reaches up to 84.92%, which shows great linear relation. Finally, after the calculation and calibration of the linear particle depolarization ratio measured during the plateau experiment campaign and observation in coastal area, the ice-water mixed cloud (0.15< p δ <0.5), water cloud ( p δ <0.15) and dusty mix(0.2< p δ <0.35) in Tibetan Plateau were occurred and classified. Meanwhile, the cirrus clouds ( p δ <0.5), water cloud, smoke and urban pollution (0.05< p

  9. Effective strategies for weight loss in post-partum women: a systematic review and meta-analysis.

    PubMed

    Lim, S; O'Reilly, S; Behrens, H; Skinner, T; Ellis, I; Dunbar, J A

    2015-11-01

    Post-partum weight loss is critical to preventing and managing obesity in women, but the results from lifestyle interventions are variable and the components associated with successful outcomes are not yet clearly identified. This study aimed to identify lifestyle intervention strategies associated with weight loss in post-partum women. MEDLINE, EMBASE, PubMed, CINAHL and four other databases were searched for lifestyle intervention studies (diet or exercise or both) in post-partum women (within 12 months of delivery) published up to July 2014. The primary outcome was weight loss. Subgroup analyses were conducted for self-monitoring, individual or group setting, intervention duration, intervention types, the use of technology as a support, and home- or centre-based interventions. From 12,673 studies, 46 studies were included in systematic review and 32 randomized controlled trials were eligible for meta-analysis (1,892 women, age 24-36 years). Studies with self-monitoring had significantly greater weight lost than those without (-4.61 kg [-7.08, -2.15] vs. -1.34 kg [-1.66, -1.02], P = 0.01 for subgroup differences). Diet and physical activity when combined were significantly more effective on weight loss compared with physical activity alone (-3.24 kg [-4.59, -1.90] vs. -1.63 kg [-2.16, -1.10], P < 0.001 for subgroup differences). Lifestyle interventions that use self-monitoring and take a combined diet-and-exercise approach have significantly greater weight loss in post-partum women. PMID:26313354

  10. Genome-Wide Analysis Indicates Lineage-Specific Gene Loss during Papilionoideae Evolution

    PubMed Central

    Gu, Yongzhe; Xing, Shilai; He, Chaoying

    2016-01-01

    Gene loss is the driving force for changes in genome and morphology; however, this particular evolutionary event has been poorly investigated in leguminous plants. Legumes (Fabaceae) have some lineage-specific and diagnostic characteristics that are distinct from other angiosperms. To understand the potential role of gene loss in the evolution of legumes, we compared six genome-sequenced legume species of Papilionoideae, the largest representative clade of Fabaceae, such as Glycine max, with 34 nonlegume plant species, such as Arabidopsis thaliana. The results showed that the putative orthologs of the 34 Arabidopsis genes belonging to 29 gene families were absent in these legume species but these were conserved in the sequenced nonlegume angiosperm lineages. Further evolutionary analyses indicated that the orthologs of these genes were almost completely lost in the Papillionoideae ancestors, thus designated as the legume lost genes (LLGs), and these underwent purifying selection in nonlegume plants. Most LLGs were functionally unknown. In Arabidopsis, two LLGs were well-known genes that played a role in plant immunity such as HARMLESS TO OZONE LAYER 1 and HOPZ-ACTIVATED RESISTANCE 1, and 16 additional LLGs were predicted to participate in plant–pathogen interactions in in silico expression and protein–protein interaction network analyses. Most of these LLGs’ orthologs in various plants were also found to be associated with biotic stress response, indicating the conserved role of these genes in plant defense. The evolutionary implication of LLGs during the development of the ability of symbiotic nitrogen fixation involving plant and bacterial interactions, which is a well-known characteristic of most legumes, is also discussed. Our work sheds light on the evolutionary implication of gene loss events in Papilionoideae evolution, as well as provides new insights into crop design to improve nitrogen fixation capacity. PMID:26868598

  11. Numerical analysis of an osseointegrated prosthesis fixation with reduced bone failure risk and periprosthetic bone loss.

    PubMed

    Tomaszewski, P K; van Diest, M; Bulstra, S K; Verdonschot, N; Verkerke, G J

    2012-07-26

    Currently available implants for direct attachment of prosthesis to the skeletal system after transfemoral amputation (OPRA system, Integrum AB, Sweden and ISP Endo/Exo prosthesis, ESKA Implants AG, Germany) show many advantages over the conventional socket fixation. However, restraining biomechanical issues such as considerable bone loss around the stem and peri-prosthetic bone fractures are present. To overcome these limiting issues a new concept of the direct intramedullary fixation was developed. We hypothesize that the new design will reduce the peri-prosthetic bone failure risk and adverse bone remodeling by restoring the natural load transfer in the femur. Generic CT-based finite element models of an intact femur and amputated bones implanted with 3 analyzed implants were created and loaded with a normal walking and a forward fall load. The strain adaptive bone remodeling theory was used to predict long-term bone changes around the implants and the periprosthetic bone failure risk was evaluated by the von Mises stress criterion. The results show that the new design provides close to physiological distribution of stresses in the bone and lower bone failure risk for the normal walking as compared to the OPRA and the ISP implants. The bone remodeling simulations did not reveal any overall bone loss around the new design, as opposed to the OPRA and the ISP implants, which induce considerable bone loss in the distal end of the femur. This positive outcome shows that the presented concept has a potential to considerably improve safety of the rehabilitation with the direct fixation implants. PMID:22677337

  12. Genome-Wide Analysis Indicates Lineage-Specific Gene Loss during Papilionoideae Evolution.

    PubMed

    Gu, Yongzhe; Xing, Shilai; He, Chaoying

    2016-03-01

    Gene loss is the driving force for changes in genome and morphology; however, this particular evolutionary event has been poorly investigated in leguminous plants. Legumes (Fabaceae) have some lineage-specific and diagnostic characteristics that are distinct from other angiosperms. To understand the potential role of gene loss in the evolution of legumes, we compared six genome-sequenced legume species of Papilionoideae, the largest representative clade of Fabaceae, such as Glycine max, with 34 nonlegume plant species, such as Arabidopsis thaliana. The results showed that the putative orthologs of the 34 Arabidopsis genes belonging to 29 gene families were absent in these legume species but these were conserved in the sequenced nonlegume angiosperm lineages. Further evolutionary analyses indicated that the orthologs of these genes were almost completely lost in the Papillionoideae ancestors, thus designated as the legume lost genes (LLGs), and these underwent purifying selection in nonlegume plants. Most LLGs were functionally unknown. In Arabidopsis, two LLGs were well-known genes that played a role in plant immunity such as HARMLESS TO OZONE LAYER 1 and HOPZ-ACTIVATED RESISTANCE 1, and 16 additional LLGs were predicted to participate in plant-pathogen interactions in in silico expression and protein-protein interaction network analyses. Most of these LLGs' orthologs in various plants were also found to be associated with biotic stress response, indicating the conserved role of these genes in plant defense. The evolutionary implication of LLGs during the development of the ability of symbiotic nitrogen fixation involving plant and bacterial interactions, which is a well-known characteristic of most legumes, is also discussed. Our work sheds light on the evolutionary implication of gene loss events in Papilionoideae evolution, as well as provides new insights into crop design to improve nitrogen fixation capacity. PMID:26868598

  13. Computational Analysis of Artificial Gravity as a Possible Countermeasure to Spaceflight Induced Bone Loss

    NASA Technical Reports Server (NTRS)

    Mulugeta, L.; Werner, C. R.; Pennline, J. A.

    2015-01-01

    During exploration class missions, such as to asteroids and Mars, astronauts will be exposed to reduced gravity for extended periods. Data has shown that astronauts lose bone mass at a rate of 1% to 2% a month in microgravity, particularly in lower extremities such as the proximal femur. Exercise countermeasures have not completely eliminated bone loss from long duration spaceflight missions, which leaves astronauts susceptible to early onset osteoporosis and greater risk of fracture. Introduction of the Advanced Resistive Exercise Device and other large exercise devices on the International Space Station (ISS), coupled with improved nutrition, has further minimized bone loss. However, unlike the ISS, exploration vehicles will have very limited volume and power available to accommodate such capabilities. Therefore, novel concepts like artificial gravity systems are being explored as a means to provide sufficient load stimulus to the musculoskeletal system to mitigate bone changes that may lead to early onset osteoporosis and increased risk of fracture. Currently, there is minimal data available to drive further research and development efforts to appropriately explore such options. Computational modeling can be leveraged to gain insight on the level of osteoprotection that may be achieved using artificial gravity produced by a spinning spacecraft or centrifuge. With this in mind, NASA's Digital Astronaut Project (DAP) has developed a bone remodeling model that has been validated for predicting volumetric bone mineral density (vBMD) changes of trabecular and cortical bone both for gravitational unloading condition and the equivalent of 1g daily load stimulus. Using this model, it is possible to simulate vBMD changes in trabecular and cortical bone under different gravity conditions. In this presentation, we will discuss our preliminary findings regarding if and how artificial gravity may be used to mitigate spaceflight induced bone loss.

  14. Food web analysis in two permanently open temperate estuaries: consequences of saltmarsh loss?

    PubMed

    Svensson, Carl J; Hyndes, Glenn A; Lavery, Paul S

    2007-09-01

    Saltmarsh vegetation, seston and microphytobenthos are all conspicuous components of most temperate estuaries and they potentially contribute to the estuarine food chain. Yet their relative contributions are unclear, as is the significance of saltmarsh losses through natural and human-induced impacts. This study aimed to quantitatively determine the contribution of various types of primary producers to detritus in the Walpole-Nornalup Estuary and Leschenault Inlet, two permanently open estuaries in SW Australia, and, estimate the flow of different types of detritus to higher trophic levels, using carbon ((13)C) and nitrogen ((15)N) stable isotopes as tracers. Results of the mixing model indicated that seston, microphytobenthos and to some extent seagrass and fringing saltmarsh were the main contributors to the detrital pool in both estuaries. However, the relative contribution of different primary producers varied both within and between estuaries. The contribution of saltmarsh was higher at sites close to rivers and dense fringing vegetation, while seston, microphytobenthos and seagrass dominated the detrital material at other sites. Benthic harpacticoid copepods were shown to feed on detritus though they appeared to actively select for different components of the detritus depending on site and estuary. Isotopic signatures of other consumers indicated that fish and invertebrates derived nutrients from MPB and detritus, either directly as food or indirectly through feeding on invertebrates. The overall contribution of saltmarsh to detritus was lower in Leschenault Inlet than in Walpole-Nornalup Estuary, possibly as a result of increased clearing of fringing vegetation around Leschenault Inlet. This pattern was however not reflected in harpacticoid food. Therefore, although losses of fringing saltmarsh around estuaries have the potential to significantly affect estuarine food webs, the significance of such losses will be site- and estuary-dependent. PMID:17382379

  15. Impedance approach to the analysis of polarization losses in antenna arrays

    NASA Astrophysics Data System (ADS)

    Tokarskij, P. L.

    1992-08-01

    The powers of the basic and parasitic components of the radiated field are expressed through currents at the inputs of the antenna array using Hermitian forms, whose coefficients comprise two matrices of polarization impedance, while their sum matrix forms the matrix of the array radiation resistance. A method for determining the mutual polarization resistances of arbitrary radiators is developed, and calculation formulas applicable to the Hertz dipole are obtained. This approach was used to calculate the polarization-loss coefficient of a hexagonal array of tourniquet radiators.

  16. Assessing weight perception accuracy to promote weight loss among U.S. female adolescents: A secondary analysis

    PubMed Central

    2010-01-01

    Background Overweight and obesity have become a global epidemic. The prevalence of overweight and obesity among U.S. adolescents has almost tripled in the last 30 years. Results from recent systematic reviews demonstrate that no single, particular intervention or strategy successfully assists overweight or obese adolescents in losing weight. An understanding of factors that influence healthy weight-loss behaviors among overweight and obese female adolescents promotes effective, multi-component weight-loss interventions. There is limited evidence demonstrating associations between demographic variables, body-mass index, and weight perception among female adolescents trying to lose weight. There is also a lack of previous studies examining the association of the accuracy of female adolescents' weight perception with their efforts to lose weight. This study, therefore, examined the associations of body-mass index, weight perception, and weight-perception accuracy with trying to lose weight and engaging in exercise as a weight-loss method among a representative sample of U.S. female adolescents. Methods A nonexperimental, descriptive, comparative secondary analysis design was conducted using data from Wave II (1996) of the National Longitudinal Study of Adolescent Health (Add Health). Data representative of U.S. female adolescents (N = 2216) were analyzed using STATA statistical software. Descriptive statistics and survey weight logistic regression were performed to determine if demographic and independent (body-mass index, weight perception, and weight perception accuracy) variables were associated with trying to lose weight and engaging in exercise as a weight-loss method. Results Age, Black or African American race, body-mass index, weight perception, and weight perceptions accuracy were consistently associated with the likeliness of trying to lose weight among U.S. female adolescents. Age, body-mass index, weight perception, and weight-perception accuracy were

  17. Capsaicin mediates apoptosis in human nasopharyngeal carcinoma NPC-TW 039 cells through mitochondrial depolarization and endoplasmic reticulum stress.

    PubMed

    Ip, S-W; Lan, S-H; Lu, H-F; Huang, A-C; Yang, J-S; Lin, J-P; Huang, H-Y; Lien, J-C; Ho, C-C; Chiu, C-F; Wood, Wg; Chung, J-G

    2012-06-01

    Capsaicin, a pungent compound found in hot chili peppers, has been reported to have antitumor activities in many human cancer cell lines, but the induction of precise apoptosis signaling pathway in human nasopharyngeal carcinoma (NPC) cells is unclear. Here, we investigated the molecular mechanisms of capsaicin-induced apoptosis in human NPC, NPC-TW 039, cells. Effects of capsaicin involved endoplasmic reticulum (ER) stress, caspase-3 activation and mitochondrial depolarization. Capsaicin-induced cytotoxic effects (cell death) through G0/G1 phase arrest and induction of apoptosis of NPC-TW 039 cells in a dose-dependent manner. Capsaicin treatment triggered ER stress by promoting the production of reactive oxygen species (ROS), increasing levels of inositol-requiring 1 enzyme (IRE1), growth arrest and DNA-damage-inducible 153 (GADD153) and glucose-regulated protein 78 (GRP78). Other effects included an increase in cytosolic Ca(2+), loss of the mitochondrial transmembrane potential (ΔΨ(m)), releases of cytochrome c and apoptosis-inducing factor (AIF), and activation of caspase-9 and -3. Furthermore, capsaicin induced increases in the ratio of Bax/Bcl-2 and abundance of apoptosis-related protein levels. These results suggest that ER stress- and mitochondria-mediated cell death is involved in capsaicin-induced apoptosis in NPC-TW 039 cells. PMID:21859781

  18. Partial intensity approach for quantitative analysis of reflection-electron-energy-loss spectra

    NASA Astrophysics Data System (ADS)

    Calliari, L.; Filippi, M.; A. Varfolomeev

    2011-08-01

    We have considered a formalism, known as partial intensity approach (PIA), previously developed to quantitatively analyze reflection electron energy loss (REEL) spectra [1,2]. The aim of the approach is, in particular, to recover the single scattering distribution of energy losses and to separate it into bulk and surface contributions, respectively referred to as the differential inverse inelastic mean free path (DIIMFP) and the differential surface excitation parameter (DSEP). As compared to [1] and [2], we have implemented a modified approach, and we have applied it to the specific geometry of the cylindrical mirror analyzer (CMA), used to acquire the REEL spectra shown here. Silicon, a material with well-defined surface and bulk plasmons, is taken as a case study to investigate the approach as a function of electron energy over the energy range typical of REELS, i.e. from 250 eV to 2 keV. Our goal is, on the one hand, to examine possible limits for the applicability of the approach and, on the other hand, to test a basic assumption of the PIA, namely that a unique DIIMFP and a unique DSEP account for REEL spectra, whatever the acquisition conditions (i.e. electron energy or angle of surface crossing) are. We find that a minimum energy exists below which the PIA cannot be applied and that the assumption of REEL spectra accounted for by unique DIIMFP and DSEP is indeed an approximation.

  19. An analysis code for the Rapid Engineering Estimation of Momentum and Energy Losses (REMEL)

    NASA Technical Reports Server (NTRS)

    Dechant, Lawrence J.

    1994-01-01

    Nonideal behavior has traditionally been modeled by defining efficiency (a comparison between actual and isentropic processes), and subsequent specification by empirical or heuristic methods. With the increasing complexity of aeropropulsion system designs, the reliability of these more traditional methods is uncertain. Computational fluid dynamics (CFD) and experimental methods can provide this information but are expensive in terms of human resources, cost, and time. This report discusses an alternative to empirical and CFD methods by applying classical analytical techniques and a simplified flow model to provide rapid engineering estimates of these losses based on steady, quasi-one-dimensional governing equations including viscous and heat transfer terms (estimated by Reynold's analogy). A preliminary verification of REMEL has been compared with full Navier-Stokes (FNS) and CFD boundary layer computations for several high-speed inlet and forebody designs. Current methods compare quite well with more complex method results and solutions compare very well with simple degenerate and asymptotic results such as Fanno flow, isentropic variable area flow, and a newly developed, combined variable area duct with friction flow solution. These solution comparisons may offer an alternative to transitional and CFD-intense methods for the rapid estimation of viscous and heat transfer losses in aeropropulsion systems.

  20. Analysis of Triplet Exciton Loss Pathways in PTB7:PC71BM Bulk Heterojunction Solar Cells

    NASA Astrophysics Data System (ADS)

    Kraus, Hannes; Heiber, Michael C.; Väth, Stefan; Kern, Julia; Deibel, Carsten; Sperlich, Andreas; Dyakonov, Vladimir

    2016-07-01

    A strategy for increasing the conversion efficiency of organic photovoltaics has been to increase the VOC by tuning the energy levels of donor and acceptor components. However, this opens up a new loss pathway from an interfacial charge transfer state to a triplet exciton (TE) state called electron back transfer (EBT), which is detrimental to device performance. To test this hypothesis, we study triplet formation in the high performing PTB7:PC71BM blend system and determine the impact of the morphology-optimizing additive 1,8-diiodoctane (DIO). Using photoluminescence and spin-sensitive optically detected magnetic resonance (ODMR) measurements at low temperature, we find that TEs form on PC71BM via intersystem crossing from singlet excitons and on PTB7 via EBT mechanism. For DIO blends with smaller fullerene domains, an increased density of PTB7 TEs is observed. The EBT process is found to be significant only at very low temperature. At 300 K, no triplets are detected via ODMR, and electrically detected magnetic resonance on optimized solar cells indicates that TEs are only present on the fullerenes. We conclude that in PTB7:PC71BM devices, TE formation via EBT is impacted by fullerene domain size at low temperature, but at room temperature, EBT does not represent a dominant loss pathway.

  1. Comprehensive Analysis of Deafness Genes in Families with Autosomal Recessive Nonsyndromic Hearing Loss

    PubMed Central

    Atik, Tahir; Onay, Huseyin; Aykut, Ayca; Bademci, Guney; Kirazli, Tayfun; Tekin, Mustafa; Ozkinay, Ferda

    2015-01-01

    Comprehensive genetic testing has the potential to become the standard of care for individuals with hearing loss. In this study, we investigated the genetic etiology of autosomal recessive nonsyndromic hearing loss (ARNSHL) in a Turkish cohort including individuals with cochlear implant, who had a pedigree suggestive of an autosomal recessive inheritance. A workflow including prescreening of GJB2 and a targeted next generation sequencing panel (Illumına TruSightTM Exome) covering 2761 genes that we briefly called as mendelian exome sequencing was used. This panel includes 102 deafness genes and a number of genes causing Mendelian disorders. Using this approach, we identified causative variants in 21 of 29 families. Three different GJB2 variants were present in seven families. Remaining 14 families had 15 different variants in other known NSHL genes (MYO7A, MYO15A, MARVELD2, TMIE, DFNB31, LOXHD1, GPSM2, TMC1, USH1G, CDH23). Of these variants, eight are novel. Mutation detection rate of our workflow is 72.4%, confirming the usefulness of targeted sequencing approach in NSHL. PMID:26561413

  2. Analysis of Triplet Exciton Loss Pathways in PTB7:PC71BM Bulk Heterojunction Solar Cells

    PubMed Central

    Kraus, Hannes; Heiber, Michael C.; Väth, Stefan; Kern, Julia; Deibel, Carsten; Sperlich, Andreas; Dyakonov, Vladimir

    2016-01-01

    A strategy for increasing the conversion efficiency of organic photovoltaics has been to increase the VOC by tuning the energy levels of donor and acceptor components. However, this opens up a new loss pathway from an interfacial charge transfer state to a triplet exciton (TE) state called electron back transfer (EBT), which is detrimental to device performance. To test this hypothesis, we study triplet formation in the high performing PTB7:PC71BM blend system and determine the impact of the morphology-optimizing additive 1,8-diiodoctane (DIO). Using photoluminescence and spin-sensitive optically detected magnetic resonance (ODMR) measurements at low temperature, we find that TEs form on PC71BM via intersystem crossing from singlet excitons and on PTB7 via EBT mechanism. For DIO blends with smaller fullerene domains, an increased density of PTB7 TEs is observed. The EBT process is found to be significant only at very low temperature. At 300 K, no triplets are detected via ODMR, and electrically detected magnetic resonance on optimized solar cells indicates that TEs are only present on the fullerenes. We conclude that in PTB7:PC71BM devices, TE formation via EBT is impacted by fullerene domain size at low temperature, but at room temperature, EBT does not represent a dominant loss pathway. PMID:27380928

  3. Analysis of Triplet Exciton Loss Pathways in PTB7:PC71BM Bulk Heterojunction Solar Cells.

    PubMed

    Kraus, Hannes; Heiber, Michael C; Väth, Stefan; Kern, Julia; Deibel, Carsten; Sperlich, Andreas; Dyakonov, Vladimir

    2016-01-01

    A strategy for increasing the conversion efficiency of organic photovoltaics has been to increase the VOC by tuning the energy levels of donor and acceptor components. However, this opens up a new loss pathway from an interfacial charge transfer state to a triplet exciton (TE) state called electron back transfer (EBT), which is detrimental to device performance. To test this hypothesis, we study triplet formation in the high performing PTB7:PC71BM blend system and determine the impact of the morphology-optimizing additive 1,8-diiodoctane (DIO). Using photoluminescence and spin-sensitive optically detected magnetic resonance (ODMR) measurements at low temperature, we find that TEs form on PC71BM via intersystem crossing from singlet excitons and on PTB7 via EBT mechanism. For DIO blends with smaller fullerene domains, an increased density of PTB7 TEs is observed. The EBT process is found to be significant only at very low temperature. At 300 K, no triplets are detected via ODMR, and electrically detected magnetic resonance on optimized solar cells indicates that TEs are only present on the fullerenes. We conclude that in PTB7:PC71BM devices, TE formation via EBT is impacted by fullerene domain size at low temperature, but at room temperature, EBT does not represent a dominant loss pathway. PMID:27380928

  4. Depolarization-induced contractile activity of smooth muscle in calcium-free solution.

    PubMed

    Mangel, A W; Nelson, D O; Rabovsky, J L; Prosser, C L; Connor, J A

    1982-01-01

    In calcium-free solution, strips of cat intestinal muscle developed slow, rhythmic electrical potential changes that triggered contractions. Some strips failed to develop spontaneous electrical activity in calcium-free solution but responded with contractions to depolarization by direct electrical stimulation or by treatment with barium chloride, potassium chloride, or acetylcholine. Similar results were obtained with segments of cat stomach, colon, esophagus, bladder, uterus, and vena cava, as well as with rabbit vena cava. In calcium-free saline, rat small intestinal muscle showed fast electrical activity with accompanying development of a tetanuslike contraction. After 60 min in calcium-free solution, cat small intestinal muscle retained 17.7% of its original concentration of calcium. It is concluded that in some smooth muscles, depolarization-triggered release of intracellular calcium does not require an associated influx of calcium. PMID:7058877

  5. Separable phases of light-evoked depolarizations in the retina of Strombus.

    PubMed

    Quandt, F N; Gillary, H L

    1980-02-01

    The waveforms of light-evoked depolarizations in Strombus retinal neurones can exhibit two sequential peaks or phases, the relative amplitudes of which vary with changes in stimulus intensity and interstimulus interval. Experiments employing either the passage of constant intracellular current or voltage clamp techniques indicate that both phases reverse polarity at intracellular potentials less negative than the resting potential. The potential at which the first phase reverses its polarity is considerably more positive than that of the second phase. The results indicate that the light-evoked depolarizations are generated by at least two different processes; these appear to be separate conductance changes, neither of which is voltage dependent. Under certain conditions, the second phase was inhibited by high extracellular concentrations of Mg2+, indicating that it may arise as a result of chemically mediated synaptic transmission. The first phase did not show such inhibition and appears to be caused by the direct action of light on the cell. PMID:7365412

  6. Failure of feedback as a putative common mechanism of spreading depolarizations in migraine and stroke

    NASA Astrophysics Data System (ADS)

    Dahlem, Markus A.; Schneider, Felix M.; Schöll, Eckehard

    2008-06-01

    The stability of cortical function depends critically on proper regulation. Under conditions of migraine and stroke a breakdown of transmembrane chemical gradients can spread through cortical tissue. A concomitant component of this emergent spatio-temporal pattern is a depolarization of cells detected as slow voltage variations. The propagation velocity of ˜3mm/min indicates a contribution of diffusion. We propose a mechanism for spreading depolarizations (SD) that rests upon a nonlocal or noninstantaneous feedback in a reaction-diffusion system. Depending upon the characteristic space and time scales of the feedback, the propagation of cortical SD can be suppressed by shifting the bifurcation line, which separates the parameter regime of pulse propagation from the regime where a local disturbance dies out. The optimization of this feedback is elaborated for different control schemes and ranges of control parameters.

  7. Structure of polarimetric purity of a Mueller matrix and sources of depolarization

    NASA Astrophysics Data System (ADS)

    Gil, José J.

    2016-06-01

    The depolarization properties of a medium with associated Mueller matrix M are characterized through two complementary sets of parameters, namely 1) the three indices of polarimetric purity (IPP), which are directly linked to the relative weights of the spectral components of M and provide complete information on the structure of polarimetric randomness, but are insensitive to the specific polarimetric behaviors that introduce the lack of randomness, and 2) the set of three components of purity (CP), constituted by the polarizance, the diattenuation and the degree of spherical purity. The relations between these sets of physical invariant quantities are studied by means of their representation into a common purity figure. Furthermore, the polarimetric properties of a general Mueller matrix M are parameterized in terms of sixteen meaningful quantities, three of them being the IPP, which together with the CP provide complete information on the integral depolarization properties of the medium.

  8. Backscatter laser depolarization studies of simulated stratospheric aerosols - Crystallized sulfuric acid droplets

    NASA Technical Reports Server (NTRS)

    Sassen, Kenneth; Zhao, Hongjie; Yu, Bing-Kun

    1989-01-01

    The optical depolarizing properties of simulated stratospheric aerosols were studied in laboratory laser (0.633 micrometer) backscattering experiments for application to polarization lidar observations. Clouds composed of sulfuric acid solution droplets, some treated with ammonia gas, were observed during evaporation. The results indicate that the formation of minute ammonium sulfate particles from the evaporation of acid droplets produces linear depolarization ratios of beta equivalent to 0.02, but beta equivalent to 0.10 to 0.15 are generated from aged acid cloud aerosols and acid droplet crystalization effects following the introduction of ammonia gas into the chamber. It is concluded that partially crystallized sulfuric acid droplets are a likely candidate for explaining the lidar beta equivalent to 0.10 values that have been observed in the lower stratosphere in the absence of the relatively strong backscattering from homogeneous sulfuric acid droplet (beta equivalent to 0) or ice crystal (beta equivalent to 0.5) clouds.

  9. Backscatter laser depolarization studies of simulated stratospheric aerosols: Crystallized sulfuric acid droplets

    NASA Technical Reports Server (NTRS)

    Sassen, Kenneth; Zhao, Hongjie; Yu, Bing-Kun

    1988-01-01

    The optical depolarizing properties of simulated stratospheric aerosols were studied in laboratory laser (0.633 micrometer) backscattering experiments for application to polarization lidar observations. Clouds composed of sulfuric acid solution droplets, some treated with ammonia gas, were observed during evaporation. The results indicate that the formation of minute ammonium sulfate particles from the evaporation of acid droplets produces linear depolarization ratios of beta equivalent to 0.02, but beta equivalent to 0.10 to 0.15 are generated from aged acid cloud aerosols and acid droplet crystallization effects following the introduction of ammonia gas into the chamber. It is concluded that partially crystallized sulfuric acid droplets are a likely candidate for explaining the lidar beta equivalent to 0.10 values that have been observed in the lower stratosphere in the absence of the relatively strong backscattering from homogeneous sulfuric acid droplet (beta equivalent to 0) or ice crystal (beta equivalent to 0.5) clouds.

  10. Measurement of the depolarization ratio of Rayleigh scattering at absorption bands

    NASA Astrophysics Data System (ADS)

    Anglister, J.; Steinberg, I. Z.

    1981-01-01

    Measurements of the depolarization ratio ρv of light scattered by the pigments lycopene and β-carotene at the red part of their absorption bands yielded values which are very close to the theoretical value 1/3 of a fully anisotropic molecular polarizability, i.e., that due to an electric dipole moment. Measurements of ρv at the blue edge of the visible absorption band of pinacyanol chloride yielded a value of 0.75 at 472.2 nm, which is the maximum value that a depolarization ratio can assume, and is attained if the average molecular polarizability is zero. This is possible only if the diagonalized polarizability tensor has at least one negative element to counterbalance the positive ones. A negative refractive index at the blue edge of the absorption band is thus experimentally demonstrated.

  11. Research in Depolarization and Extinction Coefficient of Particles in Tibetan Plateau by Lidar

    NASA Astrophysics Data System (ADS)

    Dai, Guangyao; Song, Xiaoquan; Zhai, Xiaochun; Wu, Songhua

    2016-06-01

    Vertical profiles of the depolarization ratio and the extinction coefficient of atmospheric particles in Tibetan Plateau were measured with the OUC Water Vapor, Cloud and Aerosol Lidar during the 3rd Tibetan Plateau Atmospheric Expedition Experiment Campaign in 2013 and 2014. The cloud types and phases, the spatial temporal distribution of the aerosols and the boundary layer height in the Tibetan Plateau were obtained using polarization lidar technique. In this paper, the depolarization ratio was validated with CALIOP polarization simultaneous data, and the extinction coefficient was retrieved by the Fernald method. The result implied that the atmosphere in the Tibetan Plateau was quite clean with low aerosol load and serious pollution. The ice-water mixed cumulus, water cumulus or stratus clouds in Litang and Nagqu were occurred and classified, respectively. The boundary layer height in Nagqu at average altitude over 4600 m was obtained at around 200 m-300 m, which was commonly lower than that in other observed sites.

  12. Extracting the depolarization coefficient DNN from data measured with a full acceptance detector

    NASA Astrophysics Data System (ADS)

    Hauenstein, F.; Clement, H.; Dzhygadlo, R.; Eyrich, W.; Gillitzer, A.; Grzonka, D.; Jowzaee, S.; Ritman, J.; Roderburg, E.; Röder, M.; Wintz, P.

    2016-05-01

    The spin transfer from vertically polarized beam protons to Λ or Σ hyperons of the associated strangeness production p → p →pK+ Λ and p → p →pK0Σ+ is described with the depolarization coefficient DNN. As the polarization of the hyperons is determined by their weak decays, detectors, which have a large acceptance for the decay particles, are needed. In this paper a formula is derived, which describes the depolarization coefficient DNN by count rates of a 4π detector. It is shown that formulas, which are given in publications for detectors with restricted acceptance, are specific cases of this formula for a 4π detector.

  13. Generation of vector beams using a double-wedge depolarizer: Non-quantum entanglement

    NASA Astrophysics Data System (ADS)

    Samlan, C. T.; Viswanathan, Nirmal K.

    2016-07-01

    Propagation of horizontally polarized Gaussian beam through a double-wedge depolarizer generates vector beams with spatially varying state of polarization. Jones calculus is used to show that such beams are maximally nonseparable on the basis of even (Gaussian)-odd (Hermite-Gaussian) mode parity and horizontal-vertical polarization state. The maximum nonseparability in the two degrees of freedom of the vector beam at the double wedge depolarizer output is verified experimentally using a modified Sagnac interferometer and linear analyser projected interferograms to measure the concurrence 0.94±0.002 and violation of Clauser-Horne-Shimony-Holt form of Bell-like inequality 2.704±0.024. The investigation is carried out in the context of the use of vector beams for metrological applications.

  14. Far wing depolarization of light - Generalized absorption profiles. [in laser fluorescence spectroscopy of Sr vapor

    NASA Technical Reports Server (NTRS)

    Thomann, P.; Burnett, K.; Cooper, J.

    1981-01-01

    An absorption (and/or emission) event which takes place during a strong collision is called a 'correlated event'. It is discussed how correlated events affect the far red wing depolarization of fluorescence. Attention is given to an atomic vapor which is irradiated by linearly polarized light of a frequency on the red side of the resonance line. Two limiting cases are considered, corresponding to excitation in the impact region and in the quasi-static wing. In the quasi-static wing, absorption of a photon followed by fluorescence (rather than Rayleigh scattering), occurs mostly during a collision. Correlated events dominate the scattering process. Expressions derived for the polarization of the fluorescent light are applied to far red wing depolarization. It is found that the polarization of the fluorescent light does not go to zero in the far wing, but depends crucially on the detailed nature of the anisotropy in the long-range part of the interatomic potential.

  15. Arctic polar stratospheric cloud measurements by means of a four wavelength depolarization lidar

    NASA Technical Reports Server (NTRS)

    Stefanutti, L.; Castagnoli, F.; Delguasta, M.; Flesia, C.; Godin, S.; Kolenda, J.; Kneipp, H.; Kyro, Esko; Matthey, R.; Morandi, M.

    1994-01-01

    A four wavelength depolarization backscattering lidar has been operated during the European Arctic Stratospheric Ozone Experiment (EASOE) in Sodankyl, in the Finnish Arctic. The lidar performed measurements during the months of December 1991, January, February and March 1992. The Finnish Meteorological Institute during the same period launched regularly three Radiosondes per day, and three Ozone sondes per week. Both Mt. Pinatubo aerosols and Polar Stratospheric Clouds were measured. The use of four wavelengths, respectively at 355 nm, 532 nm , 750 nm, and 850 nm permits an inversion of the lidar data to determine aerosol particle size. The depolarization technique permits the identification of Polar Stratospheric Clouds. Frequent correlation between Ozone minima and peaks in the Mt. Pinatubo aerosol maxima were detected. Measurements were carried out both within and outside the Polar Vortex.

  16. A TRP conductance modulates repolarization after sensory-dependent depolarization in Chlamydomonas reinhardtii

    PubMed Central

    Arias-Darraz, Luis; Colenso, Charlotte K; Veliz, Luis A; Vivar, Juan P; Cardenas, Sylvana; Brauchi, Sebastian

    2015-01-01

    Sensory integration is vital for motile organisms constantly exposed to changing surroundings. Chlamydomonas reinhardtii is a single-celled green alga found swimming in freshwater. In this type of alga, sensory input is first detected by membrane receptors located in the cell body, and then transduced to the beating cilia by membrane depolarization. Many components of the machinery associated with sensory integration in C. reinhardtii, such as chemoreceptors and repolarization-associated channels, are yet uncharacterized. TRP channels are known mediators for cellular sensing in animal cells and it has been suggested that the C. reinhardtii genome encodes for a set of TRP proteins. Here, by combining behavioral studies with electrophysiological experiments conducted on both population and single alga, we test whether TRP channel blockers affect algal swimming behavior. Our results suggest that a TRP conductance is associated to the repolarization that follows a depolarizing receptor potential, highlighting a primitive function of TRP proteins. PMID:26186626

  17. Toward optimizing the detection of atrial depolarization with floating bipolar electrodes.

    PubMed

    Brownlee, R R

    1989-03-01

    Some concepts derived from modern literature on the physics of cardiac muscle conduction regarding optimization of the design of electrode systems for detection of atrial depolarization and a preliminary clinical corroboration of the concepts are presented. The concepts of most import are 1) that the mechanical dimensions of sensing electrodes in all planes have to be as small as possible relative to the dimensions of the extracellular waveform dimensions associated with depolarization action potentials, and 2) that the distance between bipolar electrodes should be tuned to be greater than the dimensions of the extracellular waveform to avoid subtractive interference patterns associated with saltatory propagation in aging cardiac muscle. Additionally, in the practical application of chronic atrial sensing from a single lead for use in an implanted VDD pacing system, it is also important to consider electrode size and its effect on impedance level. PMID:2466269

  18. Surface potential at a ferroelectric grain due to asymmetric screening of depolarization fields

    SciTech Connect

    Genenko, Yuri A. Hirsch, Ofer; Erhart, Paul

    2014-03-14

    Nonlinear screening of electric depolarization fields, generated by a stripe domain structure in a ferroelectric grain of a polycrystalline material, is studied within a semiconductor model of ferroelectrics. It is shown that the maximum strength of local depolarization fields is rather determined by the electronic band gap than by the spontaneous polarization magnitude. Furthermore, field screening due to electronic band bending and due to presence of intrinsic defects leads to asymmetric space charge regions near the grain boundary, which produce an effective dipole layer at the surface of the grain. This results in the formation of a potential difference between the grain surface and its interior of the order of 1 V, which can be of either sign depending on defect transition levels and concentrations. Exemplary acceptor doping of BaTiO{sub 3} is shown to allow tuning of the said surface potential in the region between 0.1 and 1.3 V.

  19. Neutron depolarization imaging of the hydrostatic pressure dependence of inhomogeneous ferromagnets

    NASA Astrophysics Data System (ADS)

    Schulz, M.; Neubauer, A.; Böni, P.; Pfleiderer, C.

    2016-05-01

    The investigation of fragile and potentially inhomogeneous forms of ferromagnetic order under extreme conditions, such as low temperatures and high pressures, is of central interest for areas such as geophysics, correlated electron systems, as well as the optimization of materials synthesis for applications where particular material properties are required. We report neutron depolarization imaging measurements on the weak ferromagnet Ni3Al under pressures up to 10 kbar using a Cu:Be clamp cell. Using a polychromatic neutron beam with wavelengths λ ≥ 4 Å in combination with 3He neutron spin filter cells as polarizer and analyzer, we were able to track differences of the pressure response in inhomogeneous samples by virtue of high resolution neutron depolarization imaging. This provides spatially resolved and non-destructive access to the pressure dependence of the magnetic properties of inhomogeneous ferromagnetic materials.

  20. From depolarization-dependent contractions in gastrointestinal smooth muscle to aortic pulse-synchronized contractions

    PubMed Central

    Marion, Sarah B; Mangel, Allen W

    2014-01-01

    For decades, it was believed that the diameter of gastrointestinal smooth muscle cells is sufficiently narrow, and that the diffusion of calcium across the plasma membrane is sufficient, to support contractile activity. Thus, depolarization-triggered release of intracellular calcium was not believed to be operative in gastrointestinal smooth muscle. However, after the incubation of muscle segments in solutions devoid of calcium and containing the calcium chelator ethylene glycol tetraacetic acid, an alternative electrical event occurred that was distinct from normal slow waves and spikes. Subsequently, it was demonstrated in gastrointestinal smooth muscle segments that membrane depolarization associated with this alternative electrical event triggered rhythmic contractions by release of intracellular calcium. Although this concept of depolarization-triggered calcium release was iconoclastic, it has now been demonstrated in multiple gastrointestinal smooth muscle preparations. On the basis of these observations, we investigated whether a rhythmic electrical and mechanical event would occur in aortic smooth muscle under the same calcium-free conditions. The incubation of aortic segments in a solution with no added calcium plus ethylene glycol tetraacetic acid induced a fast electrical event without corresponding tension changes. On the basis of the frequency of these fast electrical events, we pursued, contrary to what has been established dogma for more than three centuries, the question of whether the smooth muscle wall of the aorta undergoes rhythmic activation during the cardiac cycle. As with depolarization-triggered contractile activity in gastrointestinal smooth muscle, it was “well known” that rhythmic activation of the aorta does not occur in synchrony with the heartbeat. In a series of experiments, however, it was demonstrated that rhythmic contractions occur in the aortic wall in synchrony with the heartbeat and share a common pacemaker with the heart

  1. Habituation in the Single Cell: Diminished Secretion of Norepinephrine with Repetitive Depolarization of PC12 Cells

    NASA Astrophysics Data System (ADS)

    McFadden, Philip N.; Koshland, Daniel E., Jr.

    1990-03-01

    Neuronally differentiated PC12 cells secrete decreasing amounts of [^3H]norepinephrine when repetitively stimulated by depolarizing concentrations of potassium ion. The decreasing response shows attributes that have been classically ascribed to response habituation, a behavior commonly observed in nervous systems but found here in a homogeneous cell type. Alteration of the habituation pattern was caused by activators of the protein kinase C pathway and of voltage-gated calcium channels.

  2. Light depolarization in off-specular reflection on submicro rough metal surfaces with imperfectly random roughness.

    PubMed

    Liu, Linsheng; Li, Xuefeng; Nonaka, Kazuhiro

    2015-02-01

    Depolarization at a rough surface relates to its roughness and irregularity (e.g., sags and crests) besides the material property. However, there is still lack of general theory to clearly describe the relationship between depolarization ratios and surface conditions, and one important reason is that the mechanism of depolarization relates to geometric parameters such as microcosmic height/particle distributions of sub-micro to nm levels. To study the mechanism in more detail, a compact laser instrument is developed, and depolarization information of a linearly polarized incident light is used for analyzing the roughness, during which a He-Ne laser source (λ = 632.8 nm) is used. Three nickel specimens with RMS roughness (Rq) less than λ/4 are fabricated and tested. Six different areas in each specimen are characterized in detail using an AFM. Rq are in the range of 34.1-155.0 nm, and the heights are non-Gaussian distribution in the first specimen and near-Gaussian distribution in the others. Off-specular inspection is carried out exactly on these 18 characterized areas, and results show that the cross-polarization ratios match quite well with Rq values of the first sample that has Rq ≤ λ/10 (or Rt ≤ λ), while they match well with maximum height, Rt, values of the other two that have Rt > λ (the maximum derivation is 11%). In addition, since this instrument is simple, portable, stable, and low-cost, it has great potential for practical online roughness testing after a linear calibration. PMID:25725823

  3. In Vivo Cluster Formation of Nisin and Lipid II Is Correlated with Membrane Depolarization

    PubMed Central

    Tol, Menno B.; Morales Angeles, Danae

    2015-01-01

    Nisin and related lantibiotics kill bacteria by pore formation or by sequestering lipid II. Some lantibiotics sequester lipid II into clusters, which were suggested to kill cells through delocalized peptidoglycan synthesis. Here, we show that cluster formation is always concomitant with (i) membrane pore formation and (ii) membrane depolarization. Nisin variants that cluster lipid II kill L-form bacteria with similar efficiency, suggesting that delocalization of peptidoglycan synthesis is not the primary killing mechanism of these lantibiotics. PMID:25870072

  4. In vivo cluster formation of nisin and lipid II is correlated with membrane depolarization.

    PubMed

    Tol, Menno B; Morales Angeles, Danae; Scheffers, Dirk-Jan

    2015-01-01

    Nisin and related lantibiotics kill bacteria by pore formation or by sequestering lipid II. Some lantibiotics sequester lipid II into clusters, which were suggested to kill cells through delocalized peptidoglycan synthesis. Here, we show that cluster formation is always concomitant with (i) membrane pore formation and (ii) membrane depolarization. Nisin variants that cluster lipid II kill L-form bacteria with similar efficiency, suggesting that delocalization of peptidoglycan synthesis is not the primary killing mechanism of these lantibiotics. PMID:25870072

  5. The Backscattering Linear Depolarization Ratio of Ice Clouds Composed of Small Ice Crystals

    NASA Astrophysics Data System (ADS)

    Schnaiter, M.; Abdelmonem, A.; Benz, S.; Leisner, T.; Möhler, O.; Wagner, R.

    2009-04-01

    The importance of small ice crystals (< 50 µm) for cirrus cloud radiative properties is a matter of controversial debate, mainly because some measurements seemed to clearly overestimate the number concentrations of small ice particles due to particle shattering on the instrument inlets. On the other hand, there is no doubt that small micrometer-sized ice crystals dominate the particle size distributions of contrails and cirrus clouds emerging from contrails. Polarisation LIDAR is frequently used to investigate the microphysics of contrails and contrail cirrus remotely. These investigations reveal unusually high maximum linear depolarization ratios of 0.5 - 0.7. The knowledge of the link between ice crystal depolarization and their size and shape is a prerequisite for the interpretation of these LIDAR data. Since young contrails consist of relatively small ice crystals with sizes typically less than 10 µm, the scattering matrix of these non-spherical particles can be calculated by the T-matrix method. In order to investigate the relation between the linear backscattering depolarization ratio and the microphysical properties of small ice particles that closely resemble those found in contrails and young cirrus, we started to run dedicated ice crystal nucleation and growth experiments at the large cloud simulation chamber AIDA of Forschungszentrum Karlsruhe. Such studies became feasible after the installation of the new in situ laser scattering and depolarization set up SIMONE at the chamber in 2006. The light scattering measurements are analyzed in the context of the microphysical properties of the ice clouds measured by optical cloud particle spectrometers, single particle imaging, and in situ infrared extinction spectroscopy. We compare our experimental results with theoretical results generated by the T-matrix method for finite cylinders. The results give new insight into the scattering depolarisation properties of small ice crystals grown under simulated

  6. Mars radar mapping: Strong depolarized echoes from the Elysium/Amazonis outflow channel complex

    NASA Technical Reports Server (NTRS)

    Harmon, J. K.; Sulzer, M. P.; Perillat, P.

    1991-01-01

    A new technique was used to make radar maps of Mars with the Arecibo radiotelescope. The observations were made during the 1990 opposition (close approach) of Mars. Among the most interesting of the preliminary results is the discovery of strong depolarized echoes from the enormous Elysium/Amazonis outflow channel complex. These strong echoes may represent rough-surface scattering off the youngest lava flows on Mars.

  7. Charge Carrier Relaxation Study in Glass-Added Barium Titanate Ceramics Using Thermally Stimulated Depolarization Current

    NASA Astrophysics Data System (ADS)

    Zhang, Qian; Zhang, Yong; Liu, Xiaolin; Song, Xiaozhen; Zhu, Jia; Baturin, Ivan

    2016-08-01

    The depolarization process of glass-added barium titanate (BaTiO3) ceramics with two different glass concentrations was investigated using a thermally stimulated depolarization current (TSDC) technique. The TSDC spectra of the glass-added BaTiO3 ceramics show three peaks. The first sharp peak near the Curie temperature is due to pyroelectric current associated with ferroelectric-paraelectric phase transition. The middle temperature peak at about 200°C showed no dependence on the depolarization current peak position in the polarization field, and the activation energies of this peak were between 0.43 eV and 0.55 eV, which are attributed to the behavior of defect dipoles related to oxygen vacancies within the BaTiO3 grains. Moreover, the high temperature peak at around 300°C indicated that the depolarization current peak position depends on the polarization temperature and decreases with increasing polarization field. The activation energy of this high temperature peak was between 0.78 eV and 0.98 eV, which is similar to the activation energy for the motion of oxygen vacancies in perovskite oxides. The high temperature peak could be attributed to the migration of oxygen vacancies across grain boundaries. In this work we developed a model in which oxygen vacancies that originated from the defect within grains migrated from the anode to the cathode and some were trapped at the grain boundaries. It is presented here and successfully interprets the appearance and behavior of these peaks.

  8. Donepezil attenuates excitotoxic damage induced by membrane depolarization of cortical neurons exposed to veratridine.

    PubMed

    Akasofu, Shigeru; Sawada, Kohei; Kosasa, Takashi; Hihara, Hiroe; Ogura, Hiroo; Akaike, Akinori

    2008-07-01

    Long-lasting membrane depolarization in cerebral ischemia causes neurotoxicity via increases of intracellular sodium concentration ([Na+]i) and calcium concentration ([Ca2+]i). Donepezil has been shown to exert neuroprotective effects in an oxygen-glucose deprivation model. In the present study, we examined the effect of donepezil on depolarization-induced neuronal cell injury resulting from prolonged opening of Na+ channels with veratridine in rat primary-cultured cortical neurons. Veratridine (10 microM)-induced neuronal cell damage was completely prevented by 0.1 microM tetrodotoxin. Pretreatment with donepezil (0.1-10 microM) for 1 day significantly decreased cell death in a concentration-dependent manner, and a potent NMDA receptor antagonist, dizocilpine (MK801), showed a neuroprotective effect at the concentration of 10 microM. The neuroprotective effect of donepezil was not affected by nicotinic or muscarinic acetylcholine receptor antagonists. We further characterized the neuroprotective properties of donepezil by measuring the effect on [Na+]i and [Ca2+]i in cells stimulated with veratridine. At 0.1-10 microM, donepezil significantly and concentration-dependently reduced the veratridine-induced increase of [Ca2+]i, whereas MK801 had no effect. At 10 microM, donepezil significantly decreased the veratridine-induced increase of [Na+]i. We also measured the effect on veratridine-induced release of the excitatory amino acids, glutamate and glycine. While donepezil decreased the release of glutamate and glycine, MK801 did not. In conclusion, our results indicate that donepezil has neuroprotective activity against depolarization-induced toxicity in rat cortical neurons via inhibition of the rapid influx of sodium and calcium ions, and via decrease of glutamate and glycine release, and also that this depolarization-induced toxicity is mediated by glutamate receptor activation. PMID:18508044

  9. Analyzing fluorophore electronic structure and depolarization by fluorescence polarizing angle spectrum

    SciTech Connect

    Mu, Taotao; Chen, Siying Zhang, Yinchao; Chen, He; Guo, Pan

    2014-07-21

    In this Letter, a method, based on stokes parameters, is developed to observe the angular displacement between the excitation and emission moments. Experiments demonstrate that when combined with degree of polarization spectrums, we can acquire the depolarization caused by angular displacement or energy migration. The method presented in this Letter can be easily realized with the existing fluorescence measuring system and may potentially make it convenient to study the fluorophore electronic structure or the mechanism of fluorescence anisotropy.

  10. Sustained NMDA receptor activation by spreading depolarizations can initiate excitotoxic injury in metabolically compromised neurons

    PubMed Central

    Aiba, Isamu; Shuttleworth, C William

    2012-01-01

    Spreading depolarizations (SDs) are slowly propagating waves of near-complete neuronal and glial depolarization. SDs have been recorded in patients with brain injury, and the incidence of SD significantly correlates with outcome severity. Although it is well accepted that the ionic dyshomeostasis of SD presents a severe metabolic burden, there is currently limited understanding of SD-induced injury processes at a cellular level. In the current study we characterized events accompanying SD in the hippocampal CA1 region of murine brain slices, using whole-cell recordings and single-cell Ca2+ imaging. We identified an excitatory phase that persisted for approximately 2 min following SD onset, and accompanied with delayed dendritic ionic dyshomeostasis. The excitatory phase coincided with a significant increase in presynaptic glutamate release, evidenced by a transient increase in spontaneous EPSC frequency and paired-pulse depression of evoked EPSCs. Activation of NMDA receptors (NMDARs) during this late excitatory phase contributed to the duration of individual neuronal depolarizations and delayed recovery of extracellular slow potential changes. Selectively targeting the NMDAR activation following SD onset (by delayed pressure application of a competitive NMDAR antagonist) significantly decreased the duration of cellular depolarizations. Recovery of dendritic Ca2+ elevations following SD were also sensitive to delayed NMDA antagonist application. Partial inhibition of neuronal energy metabolism converted SD into an irrecoverable event with persistent Ca2+ overload and membrane compromise. Delayed NMDAR block was sufficient to prevent these acute injurious events in metabolically compromised neurons. These results identify a significant contribution of a late component of SD that could underlie neuronal injury in pathological circumstances. PMID:22907056

  11. Structural relaxation mechanisms in liquid Eugenol. A depolarized light scattering study

    NASA Astrophysics Data System (ADS)

    Bezot, P.; Hesse-Bezot, C.; Roynard, D.; Jeanneaux, F.

    1988-07-01

    A depolarized light scattering study of liquid Eugenol, over a large temperature range including the supercooled region, is proposed. Comparisons with shear mechanical impedance measurements, obtained at lower frequencies, lead to more precise information on the viscoelastic parameters in the supercooled region. The structural relaxation process measurements by means of the photon correlation technique are compared to the dielectric and mechanical measurements. Molecular mechanisms are proposed.

  12. Depolarization Controls TRAIL-Sensitization and Tumor-Selective Killing of Cancer Cells: Crosstalk with ROS

    PubMed Central

    Suzuki-Karasaki, Yoshihiro; Suzuki-Karasaki, Miki; Uchida, Mayumi; Ochiai, Toyoko

    2014-01-01

    Conventional genotoxic anti-cancer drugs target the proliferative advantage of tumor cells over normal cells. This kind of approach lacks the selectivity of treatment to cancer cells, because most of the targeted pathways are essential for the survival of normal cells. As a result, traditional cancer treatments are often limited by undesirable damage to normal cells (side-effects). Ideal anti-cancer drugs are expected to be highly effective against malignant tumor cells with minimal cytotoxicity toward normal cells. Such selective killing can be achieved by targeting pathways essential for the survival of cancer cells, but not normal cells. As cancer cells are characterized by their resistance to apoptosis, selective apoptosis induction is a promising approach for selective killing of cancer cells. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising tumor-selective anti-cancer drug. However, the congenital and acquired resistance of some cancer cell types, including malignant melanoma cells, currently impedes effective TRAIL therapy, and an innovative approach that can override TRAIL resistance is urgently required. Apoptosis is characterized by cell shrinkage caused by disruption of the maintenance of the normal physiological concentrations of K+ and Na+ and intracellular ion homeostasis. The disrupted ion homeostasis leads to depolarization and apoptosis. Recent evidence suggests that depolarization is an early and prerequisite event during TRAIL-induced apoptosis. Moreover, diverse natural products and synthetic chemicals capable of depolarizing the cell membrane exhibit tumor-selective killing and TRAIL-sensitizing effects. Here, we discuss the role of depolarization in selective killing of cancer cells in connection with the emerging concept that oxidative stress is a critical mediator of mitochondrial and endoplasmic reticulum dysfunctions and serves as a tumor-selective target in cancer treatment. PMID:24910845

  13. Spreading depolarization in the brainstem mediates sudden cardiorespiratory arrest in mouse SUDEP models.

    PubMed

    Aiba, Isamu; Noebels, Jeffrey L

    2015-04-01

    Cardiorespiratory collapse after a seizure is the leading cause of sudden unexpected death in epilepsy (SUDEP) in young persons, but why only certain individuals are at risk is unknown. To identify a mechanism for this lethal cardiorespiratory failure, we examined whether genes linked to increased SUDEP risk lower the threshold for spreading depolarization (SD), a self-propagating depolarizing wave that silences neuronal networks. Mice carrying mutations in Kv1.1 potassium channels (-/-) and Scn1a sodium ion channels (+/R1407X) phenocopy many aspects of human SUDEP. In mutant, but not wild-type mice, seizures initiated by topical application of 4-aminopyridine to the cortex led to a slow, negative DC potential shift recorded in the dorsal medulla, a brainstem region that controls cardiorespiratory pacemaking. This irreversible event slowly depolarized cells and inactivated synaptic activity, producing cardiorespiratory arrest. Local initiation of SD in this region by potassium chloride microinjection also elicited electroencephalographic suppression, apnea, bradycardia, and asystole, similar to the events seen in monitored human SUDEP. In vitro study of brainstem slices confirmed that mutant mice had a lower threshold for SD elicited by metabolic substrate depletion and that immature mice were at greater risk than adults. Deletion of the gene encoding tau, which prolongs life in these mutants, also restored the normal SD threshold in Kv1.1-mutant mouse brainstem. Thus, brainstem SD may be a critical threshold event linking seizures and SUDEP. PMID:25855492

  14. Spreading depolarization in the brainstem mediates sudden cardiorespiratory arrest in mouse SUDEP models

    PubMed Central

    Aiba, Isamu; Noebels, Jeffrey L.

    2016-01-01

    Cardiorespiratory collapse after a seizure is the leading cause of sudden unexpected death in epilepsy (SUDEP) in young persons, but why only certain individuals are at risk is unknown. To identify a mechanism for this lethal cardiorespiratory failure, we examined whether genes linked to increased SUDEP risk lower the threshold for spreading depolarization (SD), a self-propagating depolarizing wave that silences neuronal networks. Mice carrying mutations in Kv1.1 potassium channels (−/−) and Scn1a sodium ion channels (+/R1407X) phenocopy many aspects of human SUDEP. In mutant, but not wild-type mice, seizures initiated by topical application of 4-aminopyridine to the cortex led to a slow, negative DC potential shift recorded in the dorsal medulla, a brainstem region that controls cardiorespiratory pacemaking. This irreversible event slowly depolarized cells and inactivated synaptic activity, producing cardiorespiratory arrest. Local initiation of SD in this region by potassium chloride microinjection also elicited electroencephalographic suppression, apnea, bradycardia, and asystole, similar to the events seen in monitored human SUDEP. In vitro study of brainstem slices confirmed that mutant mice had a lower threshold for SD elicited by metabolic substrate depletion and that immature mice were at greater risk than adults. Deletion of the gene encoding tau, which prolongs life in these mutants, also restored the normal SD threshold in Kv1.1-mutant mouse brainstem. Thus, brainstem SD may be a critical threshold event linking seizures and SUDEP. PMID:25855492

  15. Local Maps of the Polarization and Depolarization in Organic Ferroelectric Field-Effect Transistors

    PubMed Central

    Cai, Ronggang; Jonas, Alain M.

    2016-01-01

    We study the local ferroelectric polarization and depolarization of poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) in p-type ferroelectric field-effect transistors (FeFETs). Piezoresponse force microscopy (PFM) is used to obtain local maps of the polarization on model metal-semiconductor-ferroelectric stacks, and on FeFETs stripped from their top-gate electrode; transfer curves are measured on complete FeFETs. The influence of the semiconductor layer thickness and of the polarity and amplitude of the poling voltage are investigated. In accumulation, the stable “on” state consists of a uniform upward-polarized ferroelectric layer, with compensation holes accumulating at the ferroelectric/semiconducting interface. In depletion, the stable “off” state consists of a depolarized region in the center of the transistor channel, surrounded by partially downward-polarized regions over the source and drain electrodes and neighboring regions. The partial depolarization of these regions is due to the incomplete screening of polarization charges by the charges of the remote electrodes. Therefore, thinner semiconducting layers provide higher downward polarizations, which result in a more depleted transistor channel and a higher charge injection barrier between the electrodes and the semiconductor, leading to lower threshold voltages and higher on/off current values at zero gate bias. Clues for optimization of the devices are finally provided. PMID:26905962

  16. Microglial Contact Prevents Excess Depolarization and Rescues Neurons from Excitotoxicity123

    PubMed Central

    Kato, Go; Wake, Hiroaki; Akiyoshi, Ryohei; Miyamoto, Akiko; Eto, Kei; Ishikawa, Tatsuya; Moorhouse, Andrew J.

    2016-01-01

    Abstract Microglia survey and directly contact neurons in both healthy and damaged brain, but the mechanisms and functional consequences of these contacts are not yet fully elucidated. Combining two-photon imaging and patch clamping, we have developed an acute experimental model for studying the role of microglia in CNS excitotoxicity induced by neuronal hyperactivity. Our model allows us to simultaneously examine the effects of repetitive supramaximal stimulation on axonal morphology, neuronal membrane potential, and microglial migration, using cortical brain slices from Iba-1 eGFP mice. We demonstrate that microglia exert an acute and highly localized neuroprotective action under conditions of neuronal hyperactivity. Evoking repetitive action potentials in individual layer 2/3 pyramidal neurons elicited swelling of axons, but not dendrites, which was accompanied by a large, sustained depolarization of soma membrane potential. Microglial processes migrated to these swollen axons in a mechanism involving both ATP and glutamate release via volume-activated anion channels. This migration was followed by intensive microglial wrapping of affected axons and, in some cases, the removal of axonal debris that induced a rapid soma membrane repolarization back to resting potentials. When the microglial migration was pharmacologically blocked, the activity-induced depolarization continued until cell death ensued, demonstrating that the microglia–axon contact served to prevent pathological depolarization of the soma and maintain neuronal viability. This is a novel aspect of microglia surveillance: detecting, wrapping, and rescuing neuronal soma from damage due to excessive activity. PMID:27390772

  17. Large plasma-membrane depolarization precedes rapid blue-light-induced growth inhibition in cucumber

    NASA Technical Reports Server (NTRS)

    Spalding, E. P.; Cosgrove, D. J.

    1989-01-01

    Blue-light (BL)-induced suppression of elongation of etiolated Cucumis sativus L. hypocotyls began after a 30-s lag time, which was halved by increasing the fluence rate from 10 to 100 micromoles m-2 s-1. Prior to the growth suppression, the plasma-membrane of the irradiated cells depolarized by as much as 100 mV, then returned within 2-3 min to near its initial value. The potential difference measured with surface electrodes changed with an identical time course but opposite polarity. The lag time for the change in surface potential showed an inverse dependence on fluence rate, similar to the lag for the growth inhibition. Green light and red light caused neither the electrical response nor the rapid inhibition of growth. The depolarization by BL did not propagate to nonirradiated regions and exhibited a refractory period of about 10 min following a BL pulse. Fluence-response relationships for the electrical and growth responses provide correlational evidence that the plasma-membrane depolarization reflects an event in the transduction chain of this light-growth response.

  18. Classification of particle effective shape ratios in cirrus clouds based on the lidar depolarization ratio.

    PubMed

    Noel, Vincent; Chepfer, Helene; Ledanois, Guy; Delaval, Arnaud; Flamant, Pierre H

    2002-07-20

    A shape classification technique for cirrus clouds that could be applied to future spaceborne lidars is presented. A ray-tracing code has been developed to simulate backscattered and depolarized lidar signals from cirrus clouds made of hexagonal-based crystals with various compositions and optical depth, taking into account multiple scattering. This code was used first to study the sensitivity of the linear depolarization rate to cloud optical and microphysical properties, then to classify particle shapes in cirrus clouds based on depolarization ratio measurements. As an example this technique has been applied to lidar measurements from 15 mid-latitude cirrus cloud cases taken in Palaiseau, France. Results show a majority of near-unity shape ratios as well as a strong correlation between shape ratios and temperature: The lowest temperatures lead to high shape ratios. The application of this technique to space-borne measurements would allow a large-scale classification of shape ratios in cirrus clouds, leading to better knowledge of the vertical variability of shapes, their dependence on temperature, and the formation processes of clouds. PMID:12148751

  19. Correlation of Daptomycin Bactericidal Activity and Membrane Depolarization in Staphylococcus aureus

    PubMed Central

    Silverman, Jared A.; Perlmutter, Nancy G.; Shapiro, Howard M.

    2003-01-01

    The objective of this study was to further elucidate the role of membrane potential in the mechanism of action of daptomycin, a novel lipopeptide antibiotic. Membrane depolarization was measured by both fluorimetric and flow cytometric assays. Adding daptomycin (5 μg/ml) to Staphylococcus aureus gradually dissipated membrane potential. In both assays, cell viability was reduced by >99% and membrane potential was reduced by >90% within 30 min of adding daptomycin. Cell viability decreased in parallel with changes in membrane potential, demonstrating a temporal correlation between bactericidal activity and membrane depolarization. Decreases in viability and potential also showed a dose-dependent correlation. Depolarization is indicative of ion movement across the cytoplasmic membrane. Fluorescent probes were used to demonstrate Ca2+-dependent, daptomycin-triggered potassium release from S. aureus. Potassium release was also correlated with bactericidal activity. This study demonstrates a clear correlation between dissipation of membrane potential and the bactericidal activity of daptomycin. A multistep model for daptomycin's mechanism of action is proposed. PMID:12878516

  20. Quantal currents evoked by graded intracellular depolarization of crayfish motor axon terminals.

    PubMed Central

    Atwood, H L; Parnas, H; Parnas, I; Wojtowicz, J M

    1987-01-01

    1. Quantal transmitter release was examined at nerve terminals of the excitatory motor axon of the crayfish opener muscle. The magnitude of synaptic currents, recorded with macro-patch electrodes at a nerve terminal, served as a measure of quantal size. Transmitter release was initiated by pulses of depolarizing current applied intracellularly to the axonal terminals after application of tetrodotoxin. Quantal release was altered by a variety of methods and the resulting quantal output and quantal size were measured. 2. Amplitude distributions of quantal events were obtained during experimental manipulations which altered the rate of quantal release by up to 25-fold. These manipulations consisted of: varying pulse amplitude or pulse duration; facilitating the release by prolonged depolarization; and application of a potassium channel blocker, 4-aminopyridine. 3. The amplitude of quantal events is impervious to marked changes in presynaptic depolarization and is not affected by experimental procedures which promote accumulation of calcium ions in the terminals. The vesicular mechanism of release, in which transmitter substance is prepackaged in vesicles which individually undergo exocytosis at a release zone, could account for the observed results. PMID:2888878

  1. The Role of Cell Volume in the Dynamics of Seizure, Spreading Depression, and Anoxic Depolarization.

    PubMed

    Ullah, Ghanim; Wei, Yina; Dahlem, Markus A; Wechselberger, Martin; Schiff, Steven J

    2015-08-01

    Cell volume changes are ubiquitous in normal and pathological activity of the brain. Nevertheless, we know little of how cell volume affects neuronal dynamics. We here performed the first detailed study of the effects of cell volume on neuronal dynamics. By incorporating cell swelling together with dynamic ion concentrations and oxygen supply into Hodgkin-Huxley type spiking dynamics, we demonstrate the spontaneous transition between epileptic seizure and spreading depression states as the cell swells and contracts in response to changes in osmotic pressure. Our use of volume as an order parameter further revealed a dynamical definition for the experimentally described physiological ceiling that separates seizure from spreading depression, as well as predicted a second ceiling that demarcates spreading depression from anoxic depolarization. Our model highlights the neuroprotective role of glial K buffering against seizures and spreading depression, and provides novel insights into anoxic depolarization and the relevant cell swelling during ischemia. We argue that the dynamics of seizures, spreading depression, and anoxic depolarization lie along a continuum of the repertoire of the neuron membrane that can be understood only when the dynamic ion concentrations, oxygen homeostasis,and cell swelling in response to osmotic pressure are taken into consideration. Our results demonstrate the feasibility of a unified framework for a wide range of neuronal behaviors that may be of substantial importance in the understanding of and potentially developing universal intervention strategies for these pathological states. PMID:26273829

  2. The Role of Cell Volume in the Dynamics of Seizure, Spreading Depression, and Anoxic Depolarization

    PubMed Central

    Ullah, Ghanim; Wei, Yina; Dahlem, Markus A; Wechselberger, Martin; Schiff, Steven J

    2015-01-01

    Cell volume changes are ubiquitous in normal and pathological activity of the brain. Nevertheless, we know little of how cell volume affects neuronal dynamics. We here performed the first detailed study of the effects of cell volume on neuronal dynamics. By incorporating cell swelling together with dynamic ion concentrations and oxygen supply into Hodgkin-Huxley type spiking dynamics, we demonstrate the spontaneous transition between epileptic seizure and spreading depression states as the cell swells and contracts in response to changes in osmotic pressure. Our use of volume as an order parameter further revealed a dynamical definition for the experimentally described physiological ceiling that separates seizure from spreading depression, as well as predicted a second ceiling that demarcates spreading depression from anoxic depolarization. Our model highlights the neuroprotective role of glial K buffering against seizures and spreading depression, and provides novel insights into anoxic depolarization and the relevant cell swelling during ischemia. We argue that the dynamics of seizures, spreading depression, and anoxic depolarization lie along a continuum of the repertoire of the neuron membrane that can be understood only when the dynamic ion concentrations, oxygen homeostasis,and cell swelling in response to osmotic pressure are taken into consideration. Our results demonstrate the feasibility of a unified framework for a wide range of neuronal behaviors that may be of substantial importance in the understanding of and potentially developing universal intervention strategies for these pathological states. PMID:26273829

  3. Using fuel cells or anode depolarization to reduce electrowinning energy consumption

    SciTech Connect

    Cook, G.M.

    1985-01-01

    Some existing and proposed metal electrowinning plant sites have hydrogen available to reduce the need for purchased energy. Hydrogen can reduce the energy consumption of electrowinning processes by depolarizing the anode; alternatively, it can be used in a fuel cell to generate dc electricity and heat at high efficiency. The use of H/sub 2/ to depolarize an anode in zinc electrowinning has been shown to reduce overall cell voltage by nearly 2 volts at 450 A/m/sup 2/. In a fuel cell, electricity can be produced with an efficiency of about 45 to 50% compared to about 30 to 32% for conventional generating equipment and the heat produced is available at temperatures which vary from about 150/sup 0/C for phosphoric acid fuel cells to 550 to 800/sup 0/C for advanced high temperature fuel cell systems. This paper examines the increased complexity that the depolarized anode and molten carbonate fuel cell technologies impose upon the electrowinning process, assesses the extent of energy savings that are available, and provides insight into the impact on capital and operating costs. 7 references.

  4. TRAC large-break loss-of-coolant accident analysis for the AP600 design

    SciTech Connect

    Lime, J.F.; Boyack, B.E.

    1994-02-01

    This report discusses a TRAC model of the Westinghouse AP600 advanced reactor design which has been developed for analyzing large-break loss-of-coolant accident (LBLOCA) transients. A preliminary LBLOCA calculation of a 80% cold-leg break has been performed with TRAC-PF1/MOD2. The 80% break size was calculated by Westinghouse to be the most severe large-break size. The LBLOCA transient was calculated to 92 s. Peak clad temperatures (PCT) were well below the Appendix K limit of 1478 K (2200{degrees}F). Transient event times and PCT for the TRAC calculation were in reasonable agreement with those calculated by Westinghouse using their WCOBRA/TRAC code.

  5. Phase analysis of nanocomposite magnetic materials by electron energy loss spectrometry

    NASA Astrophysics Data System (ADS)

    Hébert-Souche, C.; Bernardi, J.; Schattschneider, P.; Fidler, J.; Jouffrey, B.

    2000-02-01

    EELS (electron energy loss spectrometry) in the transmission electron microscope (TEM) was used to determine the composition of a nanocrystalline magnetic specimen. The relative amounts of the hard magnetic phase Nd2Fe{14}B and the soft magnetic phase Fe3B at the point of measurement was measured by standard EELS quantification. In order to determine the structure of Fe3B present, the fine structure of the boron K-ionisation edge was analysed. Comparison of the experimental spectra with simulations of the fine structures based on the TELNES extension of the WIEN97 program package, a full potential linearised augmented plane wave approach to the calculation of electronic structure in crystals, shows that the tetragonal form of Fe3B is predominant.

  6. Transformation Optics: A Time- and Frequency-Domain Analysis of Electron-Energy Loss Spectroscopy.

    PubMed

    Kraft, Matthias; Luo, Yu; Pendry, J B

    2016-08-10

    Electron energy loss spectroscopy (EELS) and cathodoluminescence (CL) play a pivotal role in many of the cutting edge experiments in plasmonics. EELS and CL experiments are usually supported by numerical simulations, which-though accurate-may not provide as much physical insight as analytical calculations do. Fully analytical solutions to EELS and CL systems in plasmonics are rare and difficult to obtain. This paper aims to narrow this gap by introducing a new method based on transformation optics that allows to calculate the quasistatic frequency- and time-domain response of plasmonic particles under electron beam excitation. We study a nonconcentric annulus (and ellipse in the Supporting Information ) as an example. PMID:27380143

  7. A Formal Framework for the Analysis of Algorithms That Recover From Loss of Separation

    NASA Technical Reports Server (NTRS)

    Butler, RIcky W.; Munoz, Cesar A.

    2008-01-01

    We present a mathematical framework for the specification and verification of state-based conflict resolution algorithms that recover from loss of separation. In particular, we propose rigorous definitions of horizontal and vertical maneuver correctness that yield horizontal and vertical separation, respectively, in a bounded amount of time. We also provide sufficient conditions for independent correctness, i.e., separation under the assumption that only one aircraft maneuvers, and for implicitly coordinated correctness, i.e., separation under the assumption that both aircraft maneuver. An important benefit of this approach is that different aircraft can execute different algorithms and implicit coordination will still be achieved, as long as they all meet the explicit criteria of the framework. Towards this end we have sought to make the criteria as general as possible. The framework presented in this paper has been formalized and mechanically verified in the Prototype Verification System (PVS).

  8. Loss Analysis of High Power Stirling-Type Pulse Tube Cryocooler

    NASA Astrophysics Data System (ADS)

    Nakano, K.; Hiratsuka, Y.

    2015-12-01

    For the purpose of cooling high-temperature superconductor (HTS) devices, such as superconductor motors, superconducting magnetic energy storage (SMES) and current fault limiters, cryocoolers should be compact in size, light-weight, and have high efficiency and reliability. In order to meet the demand of HTS devices world-wide, the cryocooler needs to have COP efficiency >0.1. We have developed a high power Stirling-type pulse tube cryocooler (SPTC) with an in-line expander. The experimental results were reported in June 2012[1]. The cooling capacity was 210 W at 77 K and the minimum temperature was 37 K when the compressor input power was 3.8 kW. Accordingly, the COP was about 0.055. To further improve the efficiency, the energy losses in the cryocooler were analyzed. The experimental results and the numerical calculation results are reported in this paper.

  9. Blade loss transient dynamics analysis, volume 2. Task 2: TETRA 2 user's manual

    NASA Technical Reports Server (NTRS)

    Black, Gerald; Gallardo, Vincente C.

    1986-01-01

    This is the user's manual for the TETRA 2 Computer Code, a program developed in the NASA-Lewis Blade Loss Program. TETRA 2 calculates a turbine engine's dynamic structural response from applied stimuli. The calculation options are: (1) transient response; and (2) steady state forced response. Based on the method of modal syntheses, the program allows the use of linear, as well as nonlinear connecting elements. Both transient and steady state options can include: flexible Bladed Disk Module, and Nonlinear Connecting Elements (including deadband, hardening/softening spring). The transient option has the additional capability to calculate response with a squeeze film bearing module. TETRA 2 output is summarized in a plotfile which permits post processing such as FFT or graphical animation with the proper software and computer equipment.

  10. Sensorineural Hearing Loss After Treatment of Nasopharyngeal Carcinoma: A Longitudinal Analysis

    SciTech Connect

    Chan, S.H. Ng, W.T.; Kam, K.L.; Lee, Michael C.H.; Choi, C.W.; Yau, T.K.; Lee, Anne W.M.; Chow, S.K.

    2009-04-01

    Purpose: To analyze the effects of radiotherapy (RT) and chemotherapy in relation to sensorineural hearing loss (SNHL) after contemporary treatment of nasopharyngeal carcinoma. Methods and Materials: A total of 87 nasopharyngeal carcinoma patients were treated with RT or chemoradiotherapy using either three-dimensional conformal RT or intensity-modulated RT between 2004 and 2005. Tympanometry and pure-tone audiogram assessments were performed before treatment and then serially at 6-month intervals. The dose-volume data of the cochlea were analyzed. The effects of cisplatin administered in concurrent and nonconcurrent phases was explored. Results: Of the 170 eligible ears, RT (n = 30) and chemoradiotherapy (n = 140) resulted in 40% (n = 12) and 56.4% (n = 79) persistent SNHL ({>=}15 dB loss), respectively, after a median follow-up of 2 years. SNHL at a high frequency was more frequent statistically in the chemoradiotherapy group than in the RT-alone group (55% vs. 33.3%, p < 0.01), but not at a low frequency (7.9% vs. 16.7%, p = 0.14). Within the chemoradiotherapy group, the mean cochlea dose and concurrent cisplatin dose were important determinants of high-frequency SNHL, with an odds ratio of 1.07/Gy increase (p = 0.01) and an odds ratio of 1.008/mg/m{sup 2} increase (p < 0.01), respectively. Age, gender, and nonconcurrent cisplatin dose were not statistically significant factors. A mean radiation dose to the cochlea of <47 Gy would result in <15% of patients developing severe ({>=}30 dB) high-frequency SNHL. Conclusion: The results of our study have shown that high-frequency SNHL is significantly related to the mean cochlea dose and the concurrent cisplatin dose. A mean dose constraint of 47 Gy to the cochlea is recommended to minimize SNHL after chemoradiotherapy.

  11. A Global Analysis of the Effectiveness of Marine Protected Areas in Preventing Coral Loss

    PubMed Central

    Selig, Elizabeth R.; Bruno, John F.

    2010-01-01

    Background A variety of human activities have led to the recent global decline of reef-building corals [1], [2]. The ecological, social, and economic value of coral reefs has made them an international conservation priority [2], [3]. The success of Marine Protected Areas (MPAs) in restoring fish populations [4] has led to optimism that they could also benefit corals by indirectly reducing threats like overfishing, which cause coral degradation and mortality [2], [5]. However, the general efficacy of MPAs in increasing coral reef resilience has never been tested. Methodology/Principal Findings We compiled a global database of 8534 live coral cover surveys from 1969–2006 to compare annual changes in coral cover inside 310 MPAs to unprotected areas. We found that on average, coral cover within MPAs remained constant, while coral cover on unprotected reefs declined. Although the short-term differences between unprotected and protected reefs are modest, they could be significant over the long-term if the effects are temporally consistent. Our results also suggest that older MPAs were generally more effective in preventing coral loss. Initially, coral cover continued to decrease after MPA establishment. Several years later, however, rates of coral cover decline slowed and then stabilized so that further losses stopped. Conclusions/Significance These findings suggest that MPAs can be a useful tool not only for fisheries management, but also for maintaining coral cover. Furthermore, the benefits of MPAs appear to increase with the number of years since MPA establishment. Given the time needed to maximize MPA benefits, there should be increased emphasis on implementing new MPAs and strengthening the enforcement of existing MPAs. PMID:20174644

  12. The pathological effects of connexin 26 variants related to hearing loss by in silico and in vitro analysis.

    PubMed

    Kim, Hui Ram; Oh, Se-Kyung; Lee, Eun-Shil; Choi, Soo-Young; Roh, Seung-Eon; Kim, Sang Jeong; Tsukihara, Tomitake; Lee, Kyu-Yup; Jeon, Chang-Jin; Kim, Un-Kyung

    2016-03-01

    Gap junctions (GJs) are intercellular channels associated with cell-cell communication. Connexin 26 (Cx26) encoded by the GJB2 gene forms GJs of the inner ear, and mutations of GJB2 cause congenital hearing loss that can be syndromic or non-syndromic. It is difficult to predict pathogenic effects using only genetic analysis. Using ionic and biochemical coupling tests, we evaluated the pathogenic effects of Cx26 variants using computational analyses to predict structural abnormalities. For seven out of ten variants, we predicted the variation would result in a loss of GJ function, whereas the others would completely fail to form GJs. Functional studies demonstrated that, although all variants were able to function normally as hetero-oligomeric GJ channels, six variants (p.E47K, p.E47Q, p.H100L, p.H100Y, p.R127L, and p.M195L) did not function normally as homo-oligomeric GJ channels. Interestingly, GJs composed of the Cx26 variant p.R127H were able to function normally, even as homo-oligomeric GJ channels. This study demonstrates the particular location and property of an amino acid are more important mainly than the domain where they belong in the formation and function of GJ, and will provide information that is useful for the accurate diagnosis of hearing loss. PMID:26749107

  13. Numerical investigation and quantitative loss analysis of typical wet steam spontaneous condensation based on two-fluid model

    NASA Astrophysics Data System (ADS)

    Cui, Ke; Song, Yan-Ping; Chen, Huan-Long; Chen, Fu; Ooyama, Hiroharu

    2016-07-01

    A two-fluid model with the influence of inter-phase velocity-slip taken into account is proposed and a modified realizable k- ɛ turbulence model is put forward as well to make the equation set of two-fluid model closed. Based on this two-fluid model, numerical simulations are implemented on typical wet steam flow in different cases. Good consistency between numerical result and the experimental result implies that this two-fluid model is provided with high accuracy and wide applicability. The flow field analysis also shows that there exist several particular sites along the flow direction. These particular sites could illustrate the development mechanism of nucleation and droplet growing. In addition, further discussion about the flow in cascade then indicates that the presence of condensation has strong impact on the flow while the impact of inter-phase velocity-slip is relatively weaker. The composition of total pressure loss is present here, the majority of total pressure loss brought by condensation is about 8.78 % of inlet total pressure while the inter-phase velocity-slip just results in a small part of about 0.42 % of inlet total pressure, the rest of the total pressure loss is caused by pneumatic factors and this part is about 3.95 % of inlet total pressure.

  14. Estimated crop loss due to coconut mite and financial analysis of controlling the pest using the acaricide abamectin.

    PubMed

    Rezende, Daniela; Melo, José W S; Oliveira, José E M; Gondim, Manoel G C

    2016-07-01

    Reducing the losses caused by Aceria guerreronis Keifer has been an arduous task for farmers. However, there are no detailed studies on losses that simultaneously analyse correlated parameters, and very few studies that address the economic viability of chemical control, the main strategy for managing this pest. In this study the objectives were (1) to estimate the crop loss due to coconut mite and (2) to perform a financial analysis of acaricide application to control the pest. For this, the following parameters were evaluated: number and weight of fruits, liquid albumen volume, and market destination of plants with and without monthly abamectin spraying (three harvests). The costs involved in the chemical control of A. guerreronis were also quantified. Higher A. guerreronis incidence on plants resulted in a 60 % decrease in the mean number of fruits harvested per bunch and a 28 % decrease in liquid albumen volume. Mean fruit weight remained unaffected. The market destination of the harvested fruit was also affected by higher A. guerreronis incidence. Untreated plants, with higher A. guerreronis infestation intensity, produced a lower proportion of fruit intended for fresh market and higher proportions of non-marketable fruit and fruit intended for industrial processing. Despite the costs involved in controlling A. guerreronis, the difference between the profit from the treated site and the untreated site was 18,123.50 Brazilian Real; this value represents 69.1 % higher profit at the treated site. PMID:27059867

  15. Stability analysis of a two-stage tapered gyrotron traveling-wave tube amplifier with distributed losses

    SciTech Connect

    Hung, C. L.; Lian, Y. H.; Cheng, N. H.; Yeh, Y. S.; Chang, T. H.

    2012-11-15

    The two-stage tapered gyrotron traveling-wave tube (gyro-TWT) amplifier has achieved wide bandwidth in the millimeter wave range. However, possible oscillations in each stage limit this amplifier's operating beam current and thus its output power. To further enhance the amplifier's stability, distributed losses are applied to the interaction circuit of the two-stage tapered gyro-TWT. A self-consistent particle-tracing code is used for analyzing the beam-wave interactions. The stability analysis includes the effects of the wall losses and the length of each stage on the possible oscillations. Simulation results reveal that the distributed-loss method effectively stabilizes all the oscillations in the two stages. Under stable operating conditions, the device is predicted to produce a peak power of 60 kW with an efficiency of 29% and a saturated gain of 52 dB in the Ka-band. The 3-dB bandwidth is 5.7 GHz, which is approximately 16% of the center frequency.

  16. Comparative genomic hybridization in childhood acute lymphoblastic leukemia: correlation with interphase cytogenetics and loss of heterozygosity analysis.

    PubMed

    Scholz, I; Popp, S; Granzow, M; Schoell, B; Holtgreve-Grez, H; Takeuchi, S; Schrappe, M; Harbott, J; Teigler-Schlegel, A; Zimmermann, M; Fischer, C; Koeffler, H P; Bartram, C R; Jauch, A

    2001-01-15

    We used comparative genomic hybridization (CGH) to study DNA copy number changes in 71 children with acute lymphoblastic leukemia (ALL) including 50 B-lineage and 21 T-ALLs. Forty-two patients (59%) showed genomic imbalances whereby gains were more frequently observed than losses (127 vs. 29). Gains most commonly affected the entire chromosomes 21 and 10 (19.7% each), 6, 14, 18, X (15.5% each), 17 (14.1%) and 4 (11.3%). Highly hyperdiploid karyotypes (chromosome number >50) occurred more frequently in B-lineage than in T-lineage ALL (24% vs. 4.8%). In both cell lineages deletions were mainly detected on 9p (14.1%) and 12p (8.4%), and on 6q in T-lineage ALL (4.2%). These findings were compared with loss of heterozygosity (LOH) of 6q, 9p, 11q, and 12p previously performed in 56 of the 71 patients. Among 54 sites of LOH, CGH revealed losses of the respective chromosome arms in 17 LOH-positive regions (31.5%). G-banding analysis and interphase cytogenetics with subregional probes for 14 loci confirmed the presence of genomic imbalances as detected by CGH. We, therefore, conclude that, in the absence of cytogenetic data, CGH represents a suitable method for identifying hyperdiploid karyotypes as well as prognostically relevant deletions in ALL patients. PMID:11172898

  17. Absolute determination of inelastic mean-free paths and surface excitation parameters by absolute reflection electron energy loss spectrum analysis

    NASA Astrophysics Data System (ADS)

    Nagatomi, T.; Goto, K.

    2005-11-01

    An analytical approach was proposed for simultaneously determining an inelastic mean-free path (IMFP) and a surface excitation parameter (SEP) with absolute units by the analysis of an absolute experimental reflection electron energy loss spectrum. The IMFPs and SEPs in Ni were deduced for electrons of 300 to 3000 eV. The obtained IMFPs were in good agreement with those calculated using the TPP-2M equation. The Chen-type empirical formula was proposed for determining the SEP. The results confirmed the applicability of the present approach for determining the IMFP and SEP for medium-energy electrons.

  18. Excimer fluorescence compared to depolarization in the flow cytometric characterization of lateral membrane mobility in platelets

    NASA Astrophysics Data System (ADS)

    Rothe, Gregor; Schaefer, Buerk; Wimmer, Martin S.; Schmitz, Gerd

    1998-04-01

    An altered cellular membrane fluidity secondary to changes of cholesterol metabolism is a potentially important mechanism in the pathogenesis of atherosclerosis. Especially in blood platelets an increased sensitivity for stimulation dependent aggregation which is a risk factor for thrombosis has been experimentally linked to disorders of lipid and lipoprotein metabolism. The goal of this study was the development of a flow cytometric assay for the direct analysis of cellular membrane microviscosity in correlation to activation associated phenotypic changes of platelets in vitro. The analysis of fluorescence polarization following the staining of hydrophobic lipid regions of cell membranes with the fluorescent dye 1,6-diphenyl-1,3,5-hexatriene (DPH) is a well established method for the analysis of membrane fluidity. The extent of fluorescence anisotropy dependent on the rotational mobility of this fluorochrome is indirectly proportional to the microviscosity of the stained membrane subcompartment. In this study, an alternative and more simple method based on the diffusion dependent excimer formation of pyrenedecanoic acid (PDA) (J. Immunol. Methods 96:225-31, 1987) was characterized in comparison to the DPH method as a reference. Human platelets showed a rapid uptake of both DPH and PDA resulting in the staining primarily of the plasma membrane after up to 30 min of incubation. Staining analyzed at 351 nm excitation resulted in a saturation of the depolarization coefficient of DPH at 20 (mu) M but an increase of the excimer to monomer ratio of PDA with increasing dye concentration. A 'membrane fluidity coefficient' which saturated at 5 (mu) M PDA was calculated as the excimer fluorescence divided through the square of monomer fluorescence thereby correcting for the influence of dye concentration on excimer formation. The temperature dependent changes of membrane viscosity were further used as a model for the comparison of both methods. Cells analyzed at temperatures

  19. Fractal analysis as a means for the quantification of intramandibular trabecular bone loss from dental radiographs

    NASA Astrophysics Data System (ADS)

    Doyle, Michael D.; Rabin, Harold; Suri, Jasjit S.

    1991-04-01

    Atechnique is proposed which uses fractal analysis for the non- traumatic and non-invasive quantification of trabecular bone density in the mandible using standard dental radiographs. Binary images of trabecular bone patterns are derived from digitized radiographic images. Fractal analysis is then used to calculate the Hausdorif dimension (D) of the binary image patterns. Variations in D calculated with this method can be correlated with known cases of systemic osteoporosis to establish normal and abnormal ranges for the value of D.

  20. First field demonstration of end-reflection assisted Brillouin analysis for in-service loss monitoring of branched fibers in PONs

    NASA Astrophysics Data System (ADS)

    Kito, Chihiro; Takahashi, Hiroshi; Toge, Kunihiro; Manabe, Tetsuya

    2015-09-01

    The in-service loss monitoring of branched fibers in passive optical networks (PONs) is demonstrated in the field for the first time. End-reflection assisted Brillouin analysis employing a frequency shift averaging technique compensated for the variation in the Brillouin gain profile of installed optical cables. Complete loss monitoring for individual branched fibers in deployed PONs was successfully achieved.

  1. Analysis of an AP600 intermediate-size loss-of-coolant accident

    SciTech Connect

    Boyack, B.E.; Lime, J.F.

    1995-04-01

    A postulated double-ended guillotine break of an AP600 direct-vessel-injection line has been analyzed. This event is characterized as an intermediate-break loss-of-coolant accident. Most of the insights regarding the response of the AP600 safety systems to the postulated accident are derived from calculations performed with the TRAC-PF1/MOD2 code. However, complementary insights derived from a scaled experiment conducted in the ROSA facility, as well as insights based upon calculations by other codes, are also presented. Based upon the calculated and experimental results, the AP600 will not experience a core heat up and will reach a safe shutdown state using only safety-class equipment. Only the early part of the long-term cooling period initiated by In-containment Refueling Water Storage Tank injection was evaluated. Thus, the observation that the core is continuously cooled should be verified for the later phase of the long-term cooling period when sump injection and containment cooling processes are important.

  2. Electron energy loss spectroscopy analysis of the interaction of Cr and V with MWCNTs.

    PubMed

    Ilari, Gabriele M; Chawla, Vipin; Matam, Santhosh; Zhang, Yucheng; Michler, Johann; Erni, Rolf

    2016-05-01

    The presented scanning transmission electron microscopy (STEM) and electron energy-loss spectroscopy (EELS) results show the strong reaction of Cr and V with the graphitic walls of MWCNTs. For Vanadium, an interfacial VC layer could be observed at the interface between VN and MWCNTs, when the samples were heated in situ to 750°C. Knowledge about this interfacial VC layer is important for the formation of VN-MWCNT hybrid materials, used in supercapacitor electrodes, often synthesized at high temperatures. Chromium reacts at 500°C with the MWCNTs to form Cr3C2 and in some cases, dissolved the MWCNT completely. Together with the previously published results about the interaction of MWCNTs with Cu (no interaction) and Ni (a slight rehybridisation trend for the outermost MWCNT-wall observed with EELS) (Ilari et al., 2015) the influence of the valence d-orbital occupancy of 3d transition metals on the interaction strength with CNTs is shown experimentally. For a transition metal to form chemical bonds towards CNT-walls, unoccupied states in its valence d-orbitals are needed. While Ni (2 unoccupied states) interacts only slightly, Cr (5 unoccupied states) and V (7 unoccupied states) react much stronger and can dissolve the MWCNTs, at least partially. PMID:26925830

  3. Mitochondrial DNA analysis of an immigrant Basque population: loss of diversity due to founder effects.

    PubMed

    Davis, Michael C; Novak, Stephen J; Hampikian, Greg

    2011-04-01

    The Basques have a well-documented history of migration and settlement in the Americas, and they often retain cultural identity across generations. Numerous genetic studies have been carried out on European Basques; thus, immigrant Basques are an ideal population for investigating the genetic consequences of a recent human migration event. We have sampled 53 unrelated individuals with Basque ancestry in Boise, Idaho and determined the mitochondrial DNA (mtDNA) sequence variation of the first and second hypervariable regions. Thirty-six mtDNA haplotypes were detected in our sample. We found evidence of genetic changes consistent with founder effects, which is compatible with the known history of migration. Compared with the European Basque population, the immigrant Basques are significantly different in terms of haplogroup frequency distribution and diversity. They have a lower measure of weighted intralineage mean pairwise diversity (WIMP) and greater genetic distance from other European populations. These data indicate that this immigrant Basque population has experienced a reduction in genetic diversity compared with the putative source population. However, this loss of diversity is not detectable using indices of demographic history such as Tajima's D and Fu's F. This study represents the first description of mtDNA diversity in an immigrant Basque population, and our findings indicate that founder effects accompanying this relatively recent migration event have shaped the genetic diversity of this population. PMID:21404229

  4. Analysis of an AP600 intermediate-size loss-of-coolant accident

    SciTech Connect

    Boyack, B.E.; Lime, J.F.

    1995-09-01

    A postulated double-ended guillotine break of an AP600 direct-vessel-injection line has been analyzed. This event is characterized as an intermediate-break loss-of-coolant accident. Most of the insights regarding the response of the AP600 safety systems to the postulated accident are derived from calculations preformed with the TRAC-PF1/MOD2 code. However, complementary insights derived from a scaled experiment conducted in the ROSA facility, as well as insights based upon calculations by other codes, are also presented. Based upon the calculated and experimental results, the AP600 will not experience a core heat up and will reach a safe shutdown state using only safety-class equipment. Only the early part of the long-term cooling period initiated by In-containment Refueling Water Storage Tank injection was evaluated. Thus, the observation that the core is continuously cooled should be verified for the later phase of the long-term cooling period when sump injection and containment cooling processes are important.

  5. [Environmental benefit-loss analysis of agro-ecosystem in Haihe River Basin, China].

    PubMed

    Bai, Yang; Ouyang, Zhi-yun; Zheng, Hua; Xu, Wei-hua; Jiang, Bo; Fang, Yu

    2010-11-01

    According to the connotation of ecosystem services, an evaluation index system for the agro-ecosystem services in the Haihe River basin of China was established, and the economic value of the agro-ecosystem services and environmental costs were evaluated by the methods of market valuation, shadow price, and opportunity cost. In 2005, the total environmental benefit value of the agro-ecosystem services in the basin was 180. 264 billion RMB, with the regulation value of 79.416 billion RMB (44.06%) and the supporting value of 100.848 billion RMB (55.94%). Provision and cultural services were not considered in this research. From the viewpoint of functional type, the ecosystem services value from high to low was in the order of oxygen release > water conservation > nutrient cycling > soil conservation > waste purification > environmental purification > carbon sequestration > straw returning. The environmental costs of the agro-ecosystem were quite high (42. 293 billion RMB), among which, fertilizer loss was 427.42 x 10(4) t, equivalent to 15.191 billion RMB, and greenhouse gases production was calculated as 3599.65 x 10(4) t CO2, equivalent to 27. 102 billion RMB. PMID:21361021

  6. Heat loss and blood flow during hyperthermia in normal canine brain. I: Empirical study and analysis.

    PubMed

    Lyons, B E; Samulski, T V; Cox, R S; Fessenden, P

    1989-01-01

    The effects of blood flow and thermal conduction during microwave hyperthermia were investigated in normal canine brain. Heating was accomplished with an external microstrip spiral antenna and temperature measurements were made using a multichannel fluoroptic thermometry system. In order to determine cooling rates, temperature measurements made during cooling were fitted with a model consisting of a constant value and an exponential term. Data from experiments in both perfused and non-perfused brains could be fitted with this simple model. The resulting cooling rates indicated that heat loss by conduction is comparable to that by blood flow. In another series of experiments, temperature measurements were made during several 1 min cooling intervals in which the power was shut off intermittently during a 35 min heating episode. Results were consistent with a 2-3-fold increase in blood flow rate which occurred gradually throughout the course of heating. Parameters that affect the determination of cooling rates are discussed in terms of the bioheat transfer equation. These investigations demonstrate that a simple heat sink model provides a good representation of the cooling data for the thermal distributions obtained. PMID:2926187

  7. LIQHYSMES—size, loss and cost considerations for the SMES—a conceptual analysis

    NASA Astrophysics Data System (ADS)

    Sander, Michael; Neumann, Holger

    2011-10-01

    A new energy storage concept for variable renewable energy, LIQHYSMES, has been proposed which combines the use of liquid hydrogen (LH2) with superconducting magnetic energy storage (SMES). LH2 with its high volumetric energy density and, compared with compressed hydrogen, increased operational safety is the prime energy carrier for large scale stationary energy storage. But balancing load or supply fluctuations with hydrogen alone is unrealistic due to the response times of the flow control. To operate the hydrogen part more steadily, additional short-term electrical energy storage is needed. For this purpose a SMES based on coated conductors or magnesium diboride MgB2 operated in the LH2 bath, is proposed. Different solenoidal and toroidal SMES designs for the 10 GJ range are compared in terms of size and ramping losses. Cost targets for different power levels and supply periods are addressed, taking into account current developments in competing short-term storage devices like super-capacitors, batteries and flywheels.

  8. The Heat Loss Analysis and Commissioning of a Commercial Helium Dewar (SULI paper)

    SciTech Connect

    Bellamy, Marcus; /New Mexico U. /SLAC

    2006-01-04

    A low temperature cryostat suitable for many different experiments will be commissioned at the cryogenic test facility at SLAC. The scope of the project is to make commission a commercial Helium dewar. The building of the top flange will be followed from its design phase through to its finished assembly. In addition, diagnostic tools such as thermometry, level detector, pressure gauge, transfer lines for He and N2, vent lines with relief valves for He and N2 will be incorporated. Instrumentation to read and plot this data will also be included. Once the cryostat is assembled, we will cool down the cryostat to measure its performance. A typical consumption rate of Helium will be measured and from this, the overall heat leak to the dewar will be calculated. A processing instrumentation diagram (PID) of the dewar system was created with SolidEdge and was later approved and published as an official SLAC document. The plots comparing the liquid level changes of the 36 inch probe with the time and the heat loss as a function of time proved to be a valid indication that the data was interpreted and recorded correctly and that the dewar was put together successfully.

  9. Computational analysis of the curvature distribution and power losses of metal strip in tension levellers

    NASA Astrophysics Data System (ADS)

    Steinwender, L.; Kainz, A.; Krimpelstätter, K.; Zeman, K.

    2010-06-01

    Tension levelling is employed in strip processing lines to minimise residual stresses resp. to improve the strip flatness by inducing small elasto-plastic deformations. To improve the design of such machines, precise calculation models are essential to reliably predict tension losses due to plastic dissipation, power requirements of the driven bridle rolls (located upstream and downstream), reaction forces on levelling rolls as well as strains and stresses in the strip. FEM (Finite Element Method) simulations of the tension levelling process (based on Updated Lagrangian concepts) yield high computational costs due to the necessity of very fine meshes as well as due to the severely non-linear characteristics of contact, material and geometry. In an evaluation process of hierarchical models (models with different modeling levels), the reliability of both 3D and 2D modelling concepts (based on continuum and structural elements) was proved by extensive analyses as well as consistency checks against measurement data from an industrial tension leveller. To exploit the potential of computational cost savings, a customised modelling approach based on the principle of virtual work has been elaborated, which yields a drastic reduction of degrees of freedom compared to simulations by utilising commercial FEM-packages.

  10. Analysis of the juice and water losses in salted and unsalted pork samples heated in water bath. Consequences for the prediction of weight loss by transfer models.

    PubMed

    Bombrun, Laure; Gatellier, Philippe; Portanguen, Stéphane; Kondjoyan, Alain

    2015-01-01

    This study has analyzed the effect of different factors on variation of meat weight due to juice loss, and variation of water content of pork samples heated in a water bath. The weight loss (WL) was influenced by initial water content of raw meat which can be connected to meat pH, muscle type, and by pre-salting. WL was also influenced by sample thickness and by nature of the surrounding fluid. These effects were significant at 50°C and in thinner samples but decreased as meat temperature and sample thickness increased. WL showed no significant difference in response to prior freezing, applying a surface constraint during heating or varying meat salt content from 0.8 to 2.0%. The results were interpreted from literature knowledge on protein denaturation, contraction and, transport phenomena. Reliably predicting WL from water content variation during heating hinges on taking into account the loss of dry matter and the possible effects of meat pH, sample size or surrounding fluid. PMID:25443971

  11. Cost-Effectiveness of Surgically Induced Weight Loss for the Management of Type 2 Diabetes: Modeled Lifetime Analysis

    PubMed Central

    Keating, Catherine L.; Dixon, John B.; Moodie, Marjory L.; Peeters, Anna; Bulfone, Liliana; Maglianno, Dianna J.; O'Brien, Paul E.

    2009-01-01

    OBJECTIVE To estimate the cost-effectiveness of surgically induced weight loss relative to conventional therapy for the management of recently diagnosed type 2 diabetes in class I/II obese patients. RESEARCH DESIGN AND METHODS This study builds on a within-trial cost-efficacy analysis. The analysis compares the lifetime costs and quality-adjusted life-years (QALYs) between the two intervention groups. Intervention costs were extrapolated based on observed resource utilization during the trial. The proportion of patients in each intervention group with remission of diabetes at 2 years was the same as that observed in the trial. Health care costs for patients with type 2 diabetes and outcome variables required to derive estimates of QALYs were sourced from published literature. A health care system perspective was adopted. Costs and outcomes were discounted annually at 3%. Costs are presented in 2006 Australian dollars (AUD) (currency exchange: 1 AUD = 0.74 USD). RESULTS The mean number of years in diabetes remission over a lifetime was 11.4 for surgical therapy patients and 2.1 for conventional therapy patients. Over the remainder of their lifetime, surgical and conventional therapy patients lived 15.7 and 14.5 discounted QALYs, respectively. The mean discounted lifetime costs were 98,900 AUD per surgical therapy patient and 101,400 AUD per conventional therapy patient. Relative to conventional therapy, surgically induced weight loss was associated with a mean health care saving of 2,400 AUD and 1.2 additional QALYs per patient. CONCLUSIONS Surgically induced weight loss is a dominant intervention (it both saves health care costs and generates health benefits) for managing recently diagnosed type 2 diabetes in class I/II obese patients in Australia. PMID:19171720

  12. Blade loss transient dynamics analysis, volume 1. Task 2: TETRA 2 theoretical development

    NASA Technical Reports Server (NTRS)

    Gallardo, Vincente C.; Black, Gerald

    1986-01-01

    The theoretical development of the forced steady state analysis of the structural dynamic response of a turbine engine having nonlinear connecting elements is discussed. Based on modal synthesis, and the principle of harmonic balance, the governing relations are the compatibility of displacements at the nonlinear connecting elements. There are four displacement compatibility equations at each nonlinear connection, which are solved by iteration for the principle harmonic of the excitation frequency. The resulting computer program, TETRA 2, combines the original TETRA transient analysis (with flexible bladed disk) with the steady state capability. A more versatile nonlinear rub or bearing element which contains a hardening (or softening) spring, with or without deadband, is also incorporated.

  13. Thermal analysis of a planetary transmission with spherical roller bearings operating after complete loss of oil

    NASA Technical Reports Server (NTRS)

    Coe, H. H.

    1984-01-01

    Planetsys and Spherbean, two computer programs developed for the analysis of rolling element bearings, were used to simulate the thermal performance of an OH-58 helicopter main rotor transmission. A steady state and a transient thermal analysis were made and temperatures thus calculated were compared with experimental data obtained from a transmission that was operated to destruction, which occurred about 30 min after all the oil was drained from the transmission. Temperatures predicted by Spherbean were within 3% of the corresponding measured values at 15 min elapsed time and within 9% at 25 min. Spherbean also indicates a potential for high bearing cage temperatures with misalignment and outer ring rotation.

  14. Extracellular signal regulated kinase and GEF-H1 mediate depolarization-induced Rho activation and paracellular permeability increase

    PubMed Central

    Waheed, Faiza; Speight, Pam; Kawai, Glenn; Dan, Qinghong; Kapus, András; Szászi, Katalin

    2011-01-01

    Plasma membrane depolarization activates the Rho/Rho kinase (ROK) pathway and thereby enhances myosin light chain (MLC) phosphorylation, which in turn is thought to be a key regulator of paracellular permeability. However, the upstream mechanisms that couple depolarization to Rho activation and permeability changes are unknown. Here we show that three different depolarizing stimuli (high extracellular [K+], the lipophilic cation tetraphenylphosphonium or L-alanine, which is taken up by electrogenic Na+-cotransport) all provoke robust phosphorylation of Extracellular Signal Regulated Kinase (ERK) in LLC-PK1 and MDCK cells. Importantly, inhibition of ERK prevented the depolarization-induced activation of Rho. Searching for the underlying mechanism, we have identified GEF-H1 as the ERK-regulated critical exchange factor, responsible for the depolarization-induced Rho activation. This conclusion is based on our findings that a) depolarization activated GEF-H1, but not p115RhoGEF; b) siRNA-mediated GEF-H1 silencing eliminated the activation of the Rho pathway; c) ERK inhibition prevented the activation of GEF-H1. Moreover, we found that the Na+/K+ pump inhibitor ouabain also caused ERK, GEF-H1 and Rho activation, partially due to its depolarizing effect. Regarding functional consequences of this newly identified pathway, we found that depolarization increased paracellular permeability in LLC-PK1 and MDCK cells, and this effect was mitigated by inhibiting myosin using blebbistatin or a dominant negative (phosphorylation-incompetent) MLC. Taken together, we propose, that the ERK/GEF-H1/Rho/ROK/pMLC pathway could be a central mechanism whereby electrogenic transmembrane transport processes control myosin phosphorylation and regulate paracellular transport in the tubular epithelium. PMID:20237148

  15. Faraday isolator based on a TSAG single crystal with compensation of thermally induced depolarization inside magnetic field

    NASA Astrophysics Data System (ADS)

    Snetkov, Ilya; Palashov, Oleg

    2015-04-01

    A Faraday isolator based on a terbium scandium aluminum garnet (TSAG) single crystal with compensation of thermally induced depolarization inside magnetic field was demonstrated. An isolation ratio of 32 dB at 350 W cw laser radiation power was achieved. Thermally induced depolarization and thermal lens were studied and compared with similar thermal effects arising in the widely used terbium gallium garnet crystal (TGG) for the first time.

  16. Quantitative determination of optical and recombination losses in thin-film photovoltaic devices based on external quantum efficiency analysis

    NASA Astrophysics Data System (ADS)

    Nakane, Akihiro; Tampo, Hitoshi; Tamakoshi, Masato; Fujimoto, Shohei; Kim, Kang Min; Kim, Shinho; Shibata, Hajime; Niki, Shigeru; Fujiwara, Hiroyuki

    2016-08-01

    In developing photovoltaic devices with high efficiencies, quantitative determination of the carrier loss is crucial. In conventional solar-cell characterization techniques, however, photocurrent reduction originating from parasitic light absorption and carrier recombination within the light absorber cannot be assessed easily. Here, we develop a general analysis scheme in which the optical and recombination losses in submicron-textured solar cells are evaluated systematically from external quantum efficiency (EQE) spectra. In this method, the optical absorption in solar cells is first deduced by imposing the anti-reflection condition in the calculation of the absorptance spectrum, and the carrier extraction from the light absorber layer is then modeled by considering a carrier collection length from the absorber interface. Our analysis method is appropriate for a wide variety of photovoltaic devices, including kesterite solar cells [Cu2ZnSnSe4, Cu2ZnSnS4, and Cu2ZnSn(S,Se)4], zincblende CdTe solar cells, and hybrid perovskite (CH3NH3PbI3) solar cells, and provides excellent fitting to numerous EQE spectra reported earlier. Based on the results obtained from our EQE analyses, we discuss the effects of parasitic absorption and carrier recombination in different types of solar cells.

  17. Blade loss transient dynamics analysis, volume 2. Task 2: Theoretical and analytical development. Task 3: Experimental verification

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    The component element method was used to develop a transient dynamic analysis computer program which is essentially based on modal synthesis combined with a central, finite difference, numerical integration scheme. The methodology leads to a modular or building-block technique that is amenable to computer programming. To verify the analytical method, turbine engine transient response analysis (TETRA), was applied to two blade-out test vehicles that had been previously instrumented and tested. Comparison of the time dependent test data with those predicted by TETRA led to recommendations for refinement or extension of the analytical method to improve its accuracy and overcome its shortcomings. The development of working equations, their discretization, numerical solution scheme, the modular concept of engine modelling, the program logical structure and some illustrated results are discussed. The blade-loss test vehicles (rig full engine), the type of measured data, and the engine structural model are described.

  18. Using Discrete Loss Functions and Weighted Kappa for Classification: An Illustration Based on Bayesian Network Analysis

    ERIC Educational Resources Information Center

    Zwick, Rebecca; Lenaburg, Lubella

    2009-01-01

    In certain data analyses (e.g., multiple discriminant analysis and multinomial log-linear modeling), classification decisions are made based on the estimated posterior probabilities that individuals belong to each of several distinct categories. In the Bayesian network literature, this type of classification is often accomplished by assigning…

  19. Analysis of bypass activation of C3 by endotoxic LPS and loss of this potency

    PubMed Central

    Dierich, M. P.; Bitter-Suermann, D.; König, W.; Hadding, U.; Galanos, C.; Rietschel, E. T.

    1973-01-01

    Endotoxic lipopolysaccharides prepared from Salmonella minnesota smooth form (LPS-S) and rough form, R 595 (LPS-R) activate C3 in guinea-pig serum as is demonstrated by C3 kinetics and generation of anaphylatoxic activity. The activation depends on the presence of certain serum factors, one of which is the protein (SF) interacting with the cobra venom factor, on the presence of Mg++, the temperature and on dose of LPS applied. This turnover of C3 is terminated at 37° within 2 minutes (LPS-R) to 12 minutes (LPS-S) and then reaches a plateau. The amount of C3 consumption, i.e. the level of the plateau, is typical for given concentrations of LPS-S and LPS-R (intermediate plateau). Above a certain LPS-concentration additional LPS does not induce further C3 turnover (maximal plateau). While the `maximal plateau' may be explained by a limitation of the factors needed for the LPS dependent consumption of C3, the `intermediate plateau' and the termination of the action on C3 are not well understood. It is hypothesized that coating of the LPS molecule by serum protein, e.g. albumin, inactivates LPS-S and LPS-R with regard to their action on C3. C3 and C5 in normal serum concentrations appear not to be involved. It is suggested that an additional mechanism for termination of LPS action is a rapid loss of activity of LPS-induced intermediates. ImagesFIG. 8 PMID:4122408

  20. Preliminary analysis of loss-of-coolant accident in Fukushima nuclear accident

    SciTech Connect

    Su'ud, Zaki; Anshari, Rio

    2012-06-06

    Loss-of-Coolant Accident (LOCA) in Boiling Water Reactor (BWR) especially on Fukushima Nuclear Accident will be discussed in this paper. The Tohoku earthquake triggered the shutdown of nuclear power reactors at Fukushima Nuclear Power station. Though shutdown process has been completely performed, cooling process, at much smaller level than in normal operation, is needed to remove decay heat from the reactor core until the reactor reach cold-shutdown condition. If LOCA happen at this condition, it will cause the increase of reactor fuel and other core temperatures and can lead to reactor core meltdown and exposure of radioactive material to the environment such as in the Fukushima Dai Ichi nuclear accident case. In this study numerical simulation has been performed to calculate pressure composition, water level and temperature distribution on reactor during this accident. There are two coolant regulating system that operational on reactor unit 1 at this accident, Isolation Condensers (IC) system and Safety Relief Valves (SRV) system. Average mass flow of steam to the IC system in this event is 10 kg/s and could keep reactor core from uncovered about 3,2 hours and fully uncovered in 4,7 hours later. There are two coolant regulating system at operational on reactor unit 2, Reactor Core Isolation Condenser (RCIC) System and Safety Relief Valves (SRV). Average mass flow of coolant that correspond this event is 20 kg/s and could keep reactor core from uncovered about 73 hours and fully uncovered in 75 hours later. There are three coolant regulating system at operational on reactor unit 3, Reactor Core Isolation Condenser (RCIC) system, High Pressure Coolant Injection (HPCI) system and Safety Relief Valves (SRV). Average mass flow of water that correspond this event is 15 kg/s and could keep reactor core from uncovered about 37 hours and fully uncovered in 40 hours later.

  1. Layered Nickel Oxide-Based Cathodes for Lithium Cells: Analysis ofPerformance Loss Mechanisms

    SciTech Connect

    Kerlau, Marie; Reimer, Jeffrey A.; Cairns, Elton J.

    2004-10-01

    Spectroscopic and electrochemical diagnostic measurements are reported for the cell components of a Generation 2 (Gen 2) Li-Ion cell from the US Department of Energy's Advanced Technology Development (ATD) project. The cells are composed of LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2} positive electrodes (cathode), carbon graphite anodes and electrolyte consisting of 1.2 M LiPF{sub 6} in EC:EMC 3:7. Fluorophosphates were observed by {sup 19}F and {sup 31}P NMR in the electrolyte obtained from a Gen 2 cell aged 72 weeks at 45 C and presenting 50% power fade. These electrolyte decomposition products were also observed by {sup 31}P solid-state NMR on the surface of the cathode of the same cell. Samples were cut from the aged cathode from the original cell, subjected to different treatments (ultrasonic washing in anhydrous DMC, pressing, ultrasonic washing and pressing), and subsequently reassembled into small lab cells for electrochemical characterization. These treatments recovered the capacity of the electrodes to within a few percent of the original value, with the most improvement being obtained with the washed and pressed cathode. The impedance of the cathodes was also lowered after the ultrasonic washing and pressing treatments. Electron microscopy revealed that the ultrasonic washing of the aged Gen 2 cathode material resulted in the removal of small particles covering the surface of the active cathode. These findings are interpreted in terms of a model whereby capacity loss, and thus power capability, is restored by removing the fluorophosphate deposit and restoring electronic contact to the active cathode material.

  2. Preliminary analysis of loss-of-coolant accident in Fukushima nuclear accident

    NASA Astrophysics Data System (ADS)

    Su'ud, Zaki; Anshari, Rio

    2012-06-01

    Loss-of-Coolant Accident (LOCA) in Boiling Water Reactor (BWR) especially on Fukushima Nuclear Accident will be discussed in this paper. The Tohoku earthquake triggered the shutdown of nuclear power reactors at Fukushima Nuclear Power station. Though shutdown process has been completely performed, cooling process, at much smaller level than in normal operation, is needed to remove decay heat from the reactor core until the reactor reach cold-shutdown condition. If LOCA happen at this condition, it will cause the increase of reactor fuel and other core temperatures and can lead to reactor core meltdown and exposure of radioactive material to the environment such as in the Fukushima Dai Ichi nuclear accident case. In this study numerical simulation has been performed to calculate pressure composition, water level and temperature distribution on reactor during this accident. There are two coolant regulating system that operational on reactor unit 1 at this accident, Isolation Condensers (IC) system and Safety Relief Valves (SRV) system. Average mass flow of steam to the IC system in this event is 10 kg/s and could keep reactor core from uncovered about 3,2 hours and fully uncovered in 4,7 hours later. There are two coolant regulating system at operational on reactor unit 2, Reactor Core Isolation Condenser (RCIC) System and Safety Relief Valves (SRV). Average mass flow of coolant that correspond this event is 20 kg/s and could keep reactor core from uncovered about 73 hours and fully uncovered in 75 hours later. There are three coolant regulating system at operational on reactor unit 3, Reactor Core Isolation Condenser (RCIC) system, High Pressure Coolant Injection (HPCI) system and Safety Relief Valves (SRV). Average mass flow of water that correspond this event is 15 kg/s and could keep reactor core from uncovered about 37 hours and fully uncovered in 40 hours later.

  3. Mass loss

    NASA Technical Reports Server (NTRS)

    Goldberg, Leo

    1987-01-01

    Observational evidence for mass loss from cool stars is reviewed. Spectra line profiles are used for the derivation of mass-loss rates with the aid of the equation of continuity. This equation implies steady mass loss with spherical symmetry. Data from binary stars, Mira variables, and red giants in globular clusters are examined. Silicate emission is discussed as a useful indicator of mass loss in the middle infrared spectra. The use of thermal millimeter-wave radiation, Very Large Array (VLA) measurement of radio emission, and OH/IR masers are discussed as a tool for mass loss measurement. Evidence for nonsteady mass loss is also reviewed.

  4. Biophysical Insights into How Spike Threshold Depends on the Rate of Membrane Potential Depolarization in Type I and Type II Neurons

    PubMed Central

    Yi, Guo-Sheng; Wang, Jiang; Tsang, Kai-Ming; Wei, Xi-Le; Deng, Bin

    2015-01-01

    Dynamic spike threshold plays a critical role in neuronal input-output relations. In many neurons, the threshold potential depends on the rate of membrane potential depolarization (dV/dt) preceding a spike. There are two basic classes of neural excitability, i.e., Type I and Type II, according to input-output properties. Although the dynamical and biophysical basis of their spike initiation has been established, the spike threshold dynamic for each cell type has not been well described. Here, we use a biophysical model to investigate how spike threshold depends on dV/dt in two types of neuron. It is observed that Type II spike threshold is more depolarized and more sensitive to dV/dt than Type I. With phase plane analysis, we show that each threshold dynamic arises from the different separatrix and K+ current kinetics. By analyzing subthreshold properties of membrane currents, we find the activation of hyperpolarizing current prior to spike initiation is a major factor that regulates the threshold dynamics. The outward K+ current in Type I neuron does not activate at the perithresholds, which makes its spike threshold insensitive to dV/dt. The Type II K+ current activates prior to spike initiation and there is a large net hyperpolarizing current at the perithresholds, which results in a depolarized threshold as well as a pronounced threshold dynamic. These predictions are further attested in several other functionally equivalent cases of neural excitability. Our study provides a fundamental description about how intrinsic biophysical properties contribute to the threshold dynamics in Type I and Type II neurons, which could decipher their significant functions in neural coding. PMID:26083350

  5. Crescendo in Depolarization and Repolarization Heterogeneity Heralds Development of Ventricular Tachycardia in Hospitalized Patients with Decompensated Heart Failure

    PubMed Central

    Nearing, Bruce D.; Wellenius, Gregory A.; Mittleman, Murray A.; Josephson, Mark E.; Burger, Andrew J.; Verrier, Richard L.

    2012-01-01

    Background A critical need exists for reliable warning markers of in-hospital life-threatening arrhythmias. We employed a new quantitative method to track interlead heterogeneity of depolarization and repolarization to detect premonitory changes prior to ventricular tachycardia (VT) in hospitalized patients with acute decompensated heart failure. Methods and Results Ambulatory ECGs (leads V1, V5, and aVF) recorded before initiation of drug therapy from patients enrolled in the Prospective Randomized Evaluation of Cardiac Ectopy with Dobutamine or Nesiritide Therapy (PRECEDENT) trial were analyzed. R-wave and T-wave heterogeneity (RWH, TWH) were assessed by second central moment analysis and T-wave alternans (TWA) by Modified Moving Average analysis. Patients (N=44) studied included those (N = 22) with episodes of VT (≥4 beats at heart rates >100 beats/min) following ≥120 minutes of stable sinus rhythm and age- and sex-matched patients (N=22) without VT. TWA increased from 18.6±2.1μV (baseline, mean ± SEM) to 27.9±4.6μV in lead V5 at 15–30 minutes prior to VT (p<0.05) and remained elevated until the arrhythmia occurred. TWA results in V1 and aVF were similar. RWH and TWH were elevated from 164.1±33.1μV and 134.5±20.6μV (baseline) to 299.8±54.5μV and 239.2±37.0μV at 30–45 minutes prior to VT (p<0.05), respectively, preceding the crescendo in TWA by 15 minutes. Matched patients without VT did not display elevated RWH (185.5±29.4μV) or TWH (157.1±27.2μV) during the 24–hour period. Conclusions This is the first clinical demonstration of the potential utility of tracking depolarization and repolarization heterogeneity to detect crescendos in electrical instability that could forewarn of impending nonsustained ventricular tachycardia. Clinical Trial Registration http://clinicaltrials.gov; NCT00270400. PMID:22157521

  6. Electron energy-loss spectroscopy analysis of HfO2 dielectric films on strained and relaxed SiGe /Si substrates

    NASA Astrophysics Data System (ADS)

    Jang, Jiyoung; Park, Tae Joo; Kwon, Ji-Hwan; Jang, Jae Hyuck; Hwang, Cheol Seong; Kim, Miyoung

    2008-06-01

    In this investigation, HfO2 thin films were deposited on strained and strain-relaxed epitaxial-SiGe /Si substrates, and subsequently subjected to annealing. Electron energy-loss spectroscopy analysis was used to investigate the electronic structure and composition of the film as well as the interfacial layer (IL). While the energy-loss function of the dielectric films revealed predominant Si diffusion in the strained substrates, post deposition annealing (PDA) significantly influenced the diffusion and altered the local composition of the IL in strain-relaxed substrates. Analysis of electronic structures revealed the origin of significant loss of Ge atoms at the IL during PDA.

  7. Hair Loss

    MedlinePlus

    ... may cause hair loss in women. If your hair loss has occurred gradually with advancing age, FOLLICULAR DEGENERATION may be the cause. Post-pregnancy hormone changes usually reverse themselves without any treatment. While follicular degeneration cannot ...

  8. Postsynaptic Depolarization Enhances GABA Drive to Dorsomedial Hypothalamic Neurons through Somatodendritic Cholecystokinin Release.

    PubMed

    Crosby, Karen M; Baimoukhametova, Dinara V; Bains, Jaideep S; Pittman, Quentin J

    2015-09-23

    Somatodendritically released peptides alter synaptic function through a variety of mechanisms, including autocrine actions that liberate retrograde transmitters. Cholecystokinin (CCK) is a neuropeptide expressed in neurons in the dorsomedial hypothalamic nucleus (DMH), a region implicated in satiety and stress. There are clear demonstrations that exogenous CCK modulates food intake and neuropeptide expression in the DMH, but there is no information on how endogenous CCK alters synaptic properties. Here, we provide the first report of somatodendritic release of CCK in the brain in male Sprague Dawley rats. CCK is released from DMH neurons in response to repeated postsynaptic depolarizations, and acts in an autocrine fashion on CCK2 receptors to enhance postsynaptic NMDA receptor function and liberate the retrograde transmitter, nitric oxide (NO). NO subsequently acts presynaptically to enhance GABA release through a soluble guanylate cyclase-mediated pathway. These data provide the first demonstration of synaptic actions of somatodendritically released CCK in the hypothalamus and reveal a new form of retrograde plasticity, depolarization-induced potentiation of inhibition. Significance statement: Somatodendritic signaling using endocannabinoids or nitric oxide to alter the efficacy of afferent transmission is well established. Despite early convincing evidence for somatodendritic release of neurohypophysial peptides in the hypothalamus, there is only limited evidence for this mode of release for other peptides. Here, we provide the first evidence for somatodendritic release of the satiety peptide cholecystokinin (CCK) in the brain. We also reveal a new form of synaptic plasticity in which postsynaptic depolarization results in enhancement of inhibition through the somatodendritic release of CCK. PMID:26400945

  9. Utilization of Mueller matrix formalism to obtain optical targets depolarization and polarization properties

    NASA Astrophysics Data System (ADS)

    Le Roy-Brehonnet, F.; Le Jeune, B.

    Polarization is an important property of several physical phenomena such as Rayleigh and Raman ( High intensity Raman Interactions: A. Penzkofer, A. Lauberteau, and W. Kaiser, Progress in Quantum Electronics, 6) (1982) scattering ( Multi-photon Scattering Molecular Spectroscopy, S. Kielich, Progress in Optics, E. Wolf(ed.) North-Holland, Amsterdam) (1983) or fluorescence ( Principles of Fluorescence Spectroscopy, J.R. Lakowicz, Plenum Press) (1986) for example, but also for laser spectral lines ( Laser Lines in Atomic Species, C. S. Willett, Progress in Quantum Electronics, 1) (1969). So, the polarimetric aspect for the propagation in media, such as fibres (Recent progress in fibre optics, G. Cancellieri, F. Chiaraluce, Progress in Quantum Electronics, 18) (1994), the atmosphere and the sea ( Light Scattering by Small Particles (Dover, New York, 1981), must be considered. Following general considerations on the different polarimetric formalisms(Chapter I), this paper first presents a review of present theoretical works on the exploitation of the Mueller matrix (Chapter II). This is followed by original studies of our own, concerning the possibility of extracting polarizing and depolarizing properties of a target characterized by a Mueller matrix (Chapter III). We then study the depolarization effects induced by targets in the Poincare´space (Chapter IV). This depolarization is induced by multiple reflections on rough surfaces or due to partial volume scattering. We have developed an algorithm, based on the knowledge of experimental noise, to classify experimental Mueller matrices according to their polarimetric characteristics. The laser imaging set-up used is described and the method (such as dichroic and birefringent ferrofluid samples) and surfaces (such as sand and other natural targets, dielectric or metallic rough targets).

  10. Launch Vehicle Abort Analysis for Failures Leading to Loss of Control

    NASA Technical Reports Server (NTRS)

    Hanson, John M.; Hill, Ashley D.; Beard, Bernard B.

    2013-01-01

    Launch vehicle ascent is a time of high risk for an onboard crew. There is a large fraction of possible failures for which time is of the essence and a successful abort is possible if the detection and action happens quickly enough. This paper focuses on abort determination based on data already available from the Guidance, Navigation, and Control system. This work is the result of failure analysis efforts performed during the Ares I launch vehicle development program. The two primary areas of focus are the derivation of abort triggers to ensure that abort occurs as quickly as possible when needed, but that false aborts are avoided, and evaluation of success in aborting off the failing launch vehicle.

  11. Soil Phosphorus Gains and Losses with Afforestation: A Meta-analysis

    NASA Astrophysics Data System (ADS)

    McMahon, D.; Deng, Q.; Xiang, Y.; Yu, C. L.; Hui, D.; Jackson, R. B.

    2015-12-01

    Afforestation, the planting of trees on previously non-forested land, is commonly practiced around the world to provide wood, reduce erosion, and restore degraded agricultural land. Although afforestation has the potential to meet these objectives while increasing carbon uptake, its net impact on the soil depends on environmental conditions and land-use history. Availability of vital plant nutrients, such as phosphorus (P), may be altered by afforestation, but prior work has largely focused on soil carbon, and changes in soil P had not been quantitatively reviewed. We conducted a literature meta-analysis of changes in total and plant-available soil P with afforestation, compiling 49 studies representing 186 independent forest stands on five continents. Over the full dataset, mean concentration of plant-available phosphorus (mg kg-1 soil) increased by 22.7% with afforestation (bootstrapped 95% confidence interval = [15.1%, 30.7%]), while mean concentration of total phosphorus decreased by 13.5% (95% CI = [-18.4%, -8.6%]). These data reflect trends in upper mineral soil horizons, with sampling depths clustered around 20 cm and few studies reporting data below 50 cm. Differences in prior land use partially explain the substantial variation in effect size, with larger increases in available P and smaller decreases in total P when trees were planted on degraded soils. Trends in both available and total P were also enhanced with increasing time since afforestation, suggesting that changes in soil P concentrations are driven by cumulative processes rather than site preparation and planting. Our meta-analysis suggests that 1. afforestation can transform phosphorus into more plant-accessible forms, while potentially depleting total soil stocks of P, and 2. land-use history, more than climate or species planted, determines the effects of afforestation on soils' ability to meet the nutrient needs of vegetation.

  12. Identifying the Potential Loss of Monitoring Wells Using an Uncertainty Analysis

    SciTech Connect

    Freedman, Vicky L.; Waichler, Scott R.; Cole, Charles R.; Vermeul, Vince R.; Bergeron, Marcel P.

    2005-11-01

    From the mid-1940s through the 1980s, large volumes of wastewater were discharged at the Hanford Site in southeastern Washington State, causing a large-scale rise (in excess of 20 m) in the water table. When wastewater discharges ceased in 1988, groundwater mounds began to dissipate. This caused a large number of wells to go dry and has made it difficult to monitor contaminant plume migration. To identify the wells that could potentially go dry, a first order uncertainty analysis was performed using a three-dimensional, finite element code (CFEST) coupled with UCODE, a nonlinear parameter estimation code. The analysis was conducted in four steps. First, key parameter values were identified by calibrating to historical hydraulic head data. Second, the model was tested for linearity, a strict requirement for representing output uncertainty. Third, results from the calibration period were used to verify model predictions by comparing monitoring wells? wet/dry status with field data. In the final step, predictions on the number and locations of dry wells were made through the year 2048. A non-physically based model that extrapolated trends at each individual well was also tested as a predictor of a well?s wet/dry status. Results demonstrated that when uncertainty in both parameter estimates and measurement error was considered, the CFEST-based model successfully predicted the majority of dry wells, outperforming the trend model. Predictions made through the year 2048 identified approximately 50% of the wells in the monitoring well network are likely to go dry, which can aid in decisions for their replacement.

  13. High-resolution Whole-Genome Analysis of Skull Base Chordomas Implicates FHIT Loss in Chordoma Pathogenesis12

    PubMed Central

    Diaz, Roberto Jose; Guduk, Mustafa; Romagnuolo, Rocco; Smith, Christian A; Northcott, Paul; Shih, David; Berisha, Fitim; Flanagan, Adrienne; Munoz, David G; Cusimano, Michael D; Pamir, M Necmettin; Rutka, James T

    2012-01-01

    Chordoma is a rare tumor arising in the sacrum, clivus, or vertebrae. It is often not completely resectable and shows a high incidence of recurrence and progression with shortened patient survival and impaired quality of life. Chemotherapeutic options are limited to investigational therapies at present. Therefore, adjuvant therapy for control of tumor recurrence and progression is of great interest, especially in skull base lesions where complete tumor resection is often not possible because of the proximity of cranial nerves. To understand the extent of genetic instability and associated chromosomal and gene losses or gains in skull base chordoma, we undertook whole-genome single-nucleotide polymorphism microarray analysis of flash frozen surgical chordoma specimens, 21 from the clivus and 1 from C1 to C2 vertebrae. We confirm the presence of a deletion at 9p involving CDKN2A, CDKN2B, and MTAP but at a much lower rate (22%) than previously reported for sacral chordoma. At a similar frequency (21%), we found aneuploidy of chromosome 3. Tissue microarray immunohistochemistry demonstrated absent or reduced fragile histidine triad (FHIT) protein expression in 98% of sacral chordomas and 67%of skull base chordomas. Our data suggest that chromosome 3 aneuploidy and epigenetic regulation of FHIT contribute to loss of the FHIT tumor suppressor in chordoma. The finding that FHIT is lost in a majority of chordomas provides new insight into chordoma pathogenesis and points to a potential new therapeutic target for this challenging neoplasm. PMID:23019410

  14. High-resolution whole-genome analysis of skull base chordomas implicates FHIT loss in chordoma pathogenesis.

    PubMed

    Diaz, Roberto Jose; Guduk, Mustafa; Romagnuolo, Rocco; Smith, Christian A; Northcott, Paul; Shih, David; Berisha, Fitim; Flanagan, Adrienne; Munoz, David G; Cusimano, Michael D; Pamir, M Necmettin; Rutka, James T

    2012-09-01

    Chordoma is a rare tumor arising in the sacrum, clivus, or vertebrae. It is often not completely resectable and shows a high incidence of recurrence and progression with shortened patient survival and impaired quality of life. Chemotherapeutic options are limited to investigational therapies at present. Therefore, adjuvant therapy for control of tumor recurrence and progression is of great interest, especially in skull base lesions where complete tumor resection is often not possible because of the proximity of cranial nerves. To understand the extent of genetic instability and associated chromosomal and gene losses or gains in skull base chordoma, we undertook whole-genome single-nucleotide polymorphism microarray analysis of flash frozen surgical chordoma specimens, 21 from the clivus and 1 from C1 to C2 vertebrae. We confirm the presence of a deletion at 9p involving CDKN2A, CDKN2B, and MTAP but at a much lower rate (22%) than previously reported for sacral chordoma. At a similar frequency (21%), we found aneuploidy of chromosome 3. Tissue microarray immunohistochemistry demonstrated absent or reduced fragile histidine triad (FHIT) protein expression in 98% of sacral chordomas and 67%of skull base chordomas. Our data suggest that chromosome 3 aneuploidy and epigenetic regulation of FHIT contribute to loss of the FHIT tumor suppressor in chordoma. The finding that FHIT is lost in a majority of chordomas provides new insight into chordoma pathogenesis and points to a potential new therapeutic target for this challenging neoplasm. PMID:23019410

  15. Insight into the energy loss in organic solar cells based on benzotrithiophene copolymers: A dark current analysis at low temperature

    NASA Astrophysics Data System (ADS)

    Al-Naamani, Eman; Ide, Marina; Gopal, Anesh; Saeki, Akinori

    2016-02-01

    Owing to the formation of the charge transfer (CT) state, the open-circuit voltage (Voc) of organic photovoltaic (OPV) devices commonly suffers an energy loss of 0.8-1.3 eV from the effective bandgap. Benzotrithiophene (BTT)-based low-bandgap polymers that we have recently reported showed deep HOMO levels (-5.4 to -5.6 eV) and moderate optical bandgaps of 1.7-1.8 eV, which resulted in high Voc’s of 0.78-0.98 V and relatively low energy losses when blended with methano[60]fullerene (PCBM). Here, we report the temperature-dependent dark current analysis of organic solar cells of BTT copolymers:PCBM blends. Shockley diode analyses revealed the dominant contribution of CT energy and concomitant pre-exponential factor of dark saturation current density associated with charge recombination. The findings could establish a fundamental aspect to draw a design rule in BTT-based polymers towards their evolutions in OPV devices.

  16. Analysis of arable land loss and its impact on rural sustainability in Southern Jiangsu Province of China.

    PubMed

    Liu, Y S; Wang, J Y; Long, H L

    2010-01-01

    Rapid urbanization and industrialization in southern Jiangsu Province have consumed a huge amount of arable land. Through comparative analysis of land cover maps derived from TM images in 1990, 2000 and 2006, we identified the trend of arable land loss. It is found that most arable land is lost to urbanization and rural settlements development. Urban settlements, rural settlements, and industrial park-mine-transport land increased, respectively, by 87 997 ha (174.65%), 81 041 ha (104.52%), and 12 692 ha (397.99%) from 1990 to 2006. Most of the source (e.g., change from) land covers are rice paddy fields and dryland. These two covers contributed to newly urbanized areas by 37.12% and 73.52% during 1990-2000, and 46.39% and 38.86% during 2000-2006. However, the loss of arable land is weakly correlated with ecological service value, per capita net income of farmers, but positively with grain yield for some counties. Most areas in the study site have a low arable land depletion rate and a high potential for sustainable development. More attention should be directed at those counties that have a high depletion rate but a low potential for sustainable development. Rural settlements should be controlled and rationalized through legislative measures to achieve harmonious development between urban and rural areas, and sustainable development for rural areas with a minimal impact on the ecoenvironment. PMID:19853366

  17. Capacity of multiple-input multiple-output quantum depolarizing channels

    NASA Astrophysics Data System (ADS)

    Xiao, Hailin; Ouyang, Shan

    2012-08-01

    Decoherence-free subspaces (DFS) are to utilize the symmetric properties of the interaction between the system and environment so that they can be tolerant against the effect of decoherence. In this paper, we propose multiple-input multiple-output (MIMO) scheme to drive a finite-dimensional quantum system into DFS. For quantum system, the scheme is not only immune to dephasing but also feasible with currently available technology. Motivated by Shannon mutual information, we derive the capacity of MIMO quantum depolarizing channels.

  18. Fluorescence depolarization studies of sol-gel-derived glasses using a rigidochromic probe

    NASA Astrophysics Data System (ADS)

    McKiernan, John; Zink, Jeffrey I.; Dunn, Bruce S.

    1992-12-01

    The rigidochromic molecule rhenium(I)chlorotricarbonyl-2,2'-bipyridine was used in fluorescence depolarization experiments to probe the gelation, aging, and drying of silica and aluminosilicate sol-gel derived materials. These studies indicate that the local environment of the probe is fluid until well after gelation has occurred. Aluminosilicate gels show an increase in local viscosity after gelation while silica gels show no increase until the drying stage is begun. These results are compared to previous studies in which the shift of the emission band was used to indicate the rigidity in the local environment of the probe.

  19. Vertically resolved separation of dust and other aerosol types by a new lidar depolarization method.

    PubMed

    Luo, Tao; Wang, Zhien; Ferrare, Richard A; Hostetler, Chris A; Yuan, Renmin; Zhang, Damao

    2015-06-01

    This paper developed a new retrieval framework of external mixing of the dust and non-dust aerosol to predict the lidar ratio of the external mixing aerosols and to separate the contributions of non-spherical aerosols by using different depolarization ratios among dust, sea salt, smoke, and polluted aerosols. The detailed sensitivity tests and case study with the new method showed that reliable dust information could be retrieved even without prior information about the non-dust aerosol types. This new method is suitable for global dust retrievals with satellite observations, which is critical for better understanding global dust transportation and for model improvements. PMID:26072778

  20. Pinostrobin from Cajanus cajan (L.) Millsp. inhibits sodium channel-activated depolarization of mouse brain synaptoneurosomes.

    PubMed

    Nicholson, Russell A; David, Laurence S; Pan, Rui Le; Liu, Xin Min

    2010-10-01

    This investigation focuses on the in vitro neuroactive properties of pinostrobin, a substituted flavanone from Cajanus cajan (L.) Millsp. of the Fabaceae family. We demonstrate that pinostrobin inhibits voltage-gated sodium channels of mammalian brain (IC(50)=23 µM) based on the ability of this substance to suppress the depolarizing effects of the sodium channel-selective activator veratridine in a synaptoneurosomal preparation from mouse brain. The resting membrane potential of synaptoneurosomes was unaffected by pinostrobin. The pharmacological profile of pinostrobin resembles that of depressant drugs that block sodium channels. PMID:20472040