Sample records for depolarizing bipolar cells

  1. A missense mutation in Grm6 reduces but does not eliminate mGluR6 expression or rod depolarizing bipolar cell function. (United States)

    Peachey, Neal S; Hasan, Nazarul; FitzMaurice, Bernard; Burrill, Samantha; Pangeni, Gobinda; Karst, Son Yong; Reinholdt, Laura; Berry, Melissa L; Strobel, Marge; Gregg, Ronald G; McCall, Maureen A; Chang, Bo


    GRM6 encodes the metabotropic glutamate receptor 6 (mGluR6) used by retinal depolarizing bipolar cells (DBCs). Mutations in GRM6 lead to DBC dysfunction and underlie the human condition autosomal recessive complete congenital stationary night blindness. Mouse mutants for Grm6 are important models for this condition. Here we report a new Grm6 mutant, identified in an electroretinogram (ERG) screen of mice maintained at The Jackson Laboratory. The Grm6 nob8 mouse has a reduced-amplitude b-wave component of the ERG, which reflects light-evoked DBC activity. Sequencing identified a missense mutation that converts a highly conserved methionine within the ligand binding domain to leucine (p.Met66Leu). Consistent with prior studies of Grm6 mutant mice, the laminar size and structure in the Grm6 nob8 retina were comparable to control. The Grm6 nob8 phenotype is distinguished from other Grm6 mutants that carry a null allele by a reduced but not absent ERG b-wave, decreased but present expression of mGluR6 at DBC dendritic tips, and mislocalization of mGluR6 to DBC somas. Consistent with a reduced but not absent b-wave, there were a subset of retinal ganglion cells whose responses to light onset have times to peak within the range of those in control retinas. These data indicate that the p.Met66Leu mutant mGluR6 is trafficked less than control. However, the mGluR6 that is localized to the DBC dendritic tips is able to initiate DBC signal transduction. The Grm6 nob8 mouse extends the Grm6 allelic series and will be useful for elucidating the role of mGluR6 in DBC signal transduction and in human disease. NEW & NOTEWORTHY This article describes a mouse model of the human disease complete congenital stationary night blindness in which the mutation reduces but does not eliminate GRM6 expression and bipolar cell function, a distinct phenotype from that seen in other Grm6 mouse models.

  2. Depolarizing Effects of Daikenchuto on Interstitial Cells of Cajal from Mouse Small Intestine. (United States)

    Kim, Hyungwoo; Kim, Hyun Jung; Yang, Dongki; Jung, Myeong Ho; Kim, Byung Joo


    Daikenchuto (DKT; TJ-100, TU-100), a traditional herbal medicineis used in modern medicine to treat gastrointestinal (GI) functional disorders. Interstitial cells of Cajal (ICCs) are the pacemaker cells of the GI tract and play important roles in the regulation of GI motility. The objective of this study was to investigate the effects of DKT on the pacemaker potentials (PPs) of cultured ICCs from murine small intestine. Enzymatic digestions were used to dissociate ICCs from mouse small intestine tissues. All experiments on ICCs were performed after 12 h of culture. The whole-cell patch-clamp configuration was used to record ICC PPs (current clamp mode). All experiments were performed at 30-32°C. In current-clamp modeDKT depolarized and concentration-dependently decreased the amplitudes of PPs. Y25130 (a 5-HT 3 receptor antagonist) or SB269970 (a 5-HT 7 receptor antagonist) did not block DKT-induced PP depolarization, but RS39604 (a 5-HT 4 receptor antagonist) did. Methoctramine (a muscarinic M 2 receptor antagonist) failed to block DKT-induced PP depolarization, but pretreating 4-diphenylacetoxy-N-methylpiperidine methiodide (a muscarinic M 3 receptor antagonist) facilitated blockade of DKT-induced PP depolarization. Pretreatment with an external Ca 2+ -free solution or thapsigargin abolished PPsand under these conditions, DKT did not induce PP depolarization. Furthermore Ginseng radix and Zingiberis rhizomes depolarized PPs, whereas Zanthoxyli fructus fruit (the third component of DKT) hyperpolarized PPs. These results suggest that DKT depolarizes ICC PPs in an internal or external Ca 2+ -dependent manner by stimulating 5-HT 4 and M 3 receptors. Furthermore, the authors suspect that the component in DKT largely responsible for depolarization is probably also a component of Ginseng radix and Zingiberis rhizomes. Daikenchuto (DKT) depolarized and concentration-dependently decreased the amplitudes of pacemaker potentials (PPs)Y25130 (a 5-HT 3 receptor antagonist) or

  3. Bipolar plates for PEM fuel cells (United States)

    Middelman, E.; Kout, W.; Vogelaar, B.; Lenssen, J.; de Waal, E.

    The bipolar plates are in weight and volume the major part of the PEM fuel cell stack, and are also a significant contributor to the stack costs. The bipolar plate is therefore a key component if power density has to increase and costs must come down. Three cell plate technologies are expected to reach targeted cost price levels, all having specific advantages and drawbacks. NedStack has developed a conductive composite materials and a production process for fuel cell plates (bipolar and mono-polar). The material has a high electric and thermal conductivity, and can be processed into bipolar plates by a proprietary molding process. Process cycle time has been reduced to less than 10 s, making the material and process suitable for economical mass production. Other development work to increase material efficiency resulted in thin bipolar plates with integrated cooling channels, and integrated seals, and in two-component bipolar plates. Total thickness of the bipolar plates is now less than 3 mm, and will be reduced to 2 mm in the near future. With these thin integrated plates it is possible to increase power density up to 2 kW/l and 2 kW/kg, while at the same time reducing cost by integrating other functions and less material use.

  4. Normal chemotaxis in Dictyostelium discoideum cells with a depolarized plasma membrane potential

    NARCIS (Netherlands)

    Duijn, Bert van; Vogelzang, Sake A.; Ypey, Dirk L.; Molen, Loek G. van der; Haastert, Peter J.M. van


    We examined a possible role for the plasma membrane potential in signal transduction during cyclic AMP-induced chemotaxis in the cellular slime mold Dictyostelium discoideum. Chemotaxis, cyclic GMP and cyclic AMP responses in cells with a depolarized membrane potential were measured. Cells can be

  5. Weaver mutant mouse cerebellar granule cells respond normally to chronic depolarization

    DEFF Research Database (Denmark)

    Bjerregaard, Annette; Mogensen, Helle Smidt; Hack, N


    We studied the effects of chronic K(+)-induced membrane depolarization and treatment with N-methyl-D-aspartate (NMDA) on cerebellar granule cells (CGCs) from weaver mutant mice and non-weaver litter-mates. The weaver mutation is a Gly-to-Ser substitution in a conserved region of the Girk2 G prote...

  6. Electrical coupling between A17 cells enhances reciprocal inhibitory feedback to rod bipolar cells. (United States)

    Elgueta, Claudio; Leroy, Felix; Vielma, Alex H; Schmachtenberg, Oliver; Palacios, Adrian G


    A17 amacrine cells are an important part of the scotopic pathway. Their synaptic varicosities receive glutamatergic inputs from rod bipolar cells (RBC) and release GABA onto the same RBC terminal, forming a reciprocal feedback that shapes RBC depolarization. Here, using patch-clamp recordings, we characterized electrical coupling between A17 cells of the rat retina and report the presence of strongly interconnected and non-coupled A17 cells. In coupled A17 cells, evoked currents preferentially flow out of the cell through GJs and cross-synchronization of presynaptic signals in a pair of A17 cells is correlated to their coupling degree. Moreover, we demonstrate that stimulation of one A17 cell can induce electrical and calcium transients in neighboring A17 cells, thus confirming a functional flow of information through electrical synapses in the A17 coupled network. Finally, blocking GJs caused a strong decrease in the amplitude of the inhibitory feedback onto RBCs. We therefore propose that electrical coupling between A17 cells enhances feedback onto RBCs by synchronizing and facilitating GABA release from inhibitory varicosities surrounding each RBC axon terminal. GJs between A17 cells are therefore critical in shaping the visual flow through the scotopic pathway.

  7. Permissive effect of dexamethasone on the increase of proenkephalin mRNA induced by depolarization of chromaffin cells

    International Nuclear Information System (INIS)

    Naranjo, J.R.; Mocchetti, I.; Schwartz, J.P.; Costa, E.


    In cultured bovine chromaffin cells, changes in the dynamic state of enkephalin stores elicited experimentally were studied by measuring cellular proenkephalin mRNA, as well as enkephalin precursors and authentic enkephalin content of cells and culture media. In parallel, tyrosine hydroxylase mRNA and catecholamine cell content were also determined. Low concentrations (0.5-100 pM) of dexamethasone increased the cell contents of proenkephalin mRNA and enkephalin-containing peptides. High concentrations of the hormone(1 μM) were required to increase the cell contents of tyrosine hydroxylase mRNA and catecholamines. Depolarization of the cells with 10 μM veratridine resulted in a depletion of enkephalin and catecholamine stores after 24 hr. The enkephalin, but not the catecholamine, content was restored by 48 hr. An increase in proenkephalin mRNA content might account for the recovery; this increase was curtailed by tetrodotoxin and enhanced by 10 pM dexamethasone. Tyrosine hydroxylase mRNA content was not significantly modified by depolarization, even in the presence of 1 μM dexamethasone. Aldosterone, progesterone, testosterone, or estradiol (1 μM) failed to change proenkephalin mRNA. Hence, dexamethasone appears to exert a specific permissive action on the stimulation of the proenkephalin gene elicited by depolarization. Though the catecholamines and enkephalins are localized in the same chromaffin granules and are coreleased by depolarization, the genes coding for the processes that are rate limiting in the production of these neuromodulators can be differentially regulated

  8. Retinal ganglion cells: mechanisms underlying depolarization block and differential responses to high frequency electrical stimulation of ON and OFF cells (United States)

    Kameneva, T.; Maturana, M. I.; Hadjinicolaou, A. E.; Cloherty, S. L.; Ibbotson, M. R.; Grayden, D. B.; Burkitt, A. N.; Meffin, H.


    Objective. ON and OFF retinal ganglion cells (RGCs) are known to have non-monotonic responses to increasing amplitudes of high frequency (2 kHz) biphasic electrical stimulation. That is, an increase in stimulation amplitude causes an increase in the cell’s spike rate up to a peak value above which further increases in stimulation amplitude cause the cell to decrease its activity. The peak response for ON and OFF cells occurs at different stimulation amplitudes, which allows differential stimulation of these functional cell types. In this study, we investigate the mechanisms underlying the non-monotonic responses of ON and OFF brisk-transient RGCs and the mechanisms underlying their differential responses. Approach. Using in vitro patch-clamp recordings from rat RGCs, together with simulations of single and multiple compartment Hodgkin-Huxley models, we show that the non-monotonic response to increasing amplitudes of stimulation is due to depolarization block, a change in the membrane potential that prevents the cell from generating action potentials. Main results. We show that the onset for depolarization block depends on the amplitude and frequency of stimulation and reveal the biophysical mechanisms that lead to depolarization block during high frequency stimulation. Our results indicate that differences in transmembrane potassium conductance lead to shifts of the stimulus currents that generate peak spike rates, suggesting that the differential responses of ON and OFF cells may be due to differences in the expression of this current type. We also show that the length of the axon’s high sodium channel band (SOCB) affects non-monotonic responses and the stimulation amplitude that leads to the peak spike rate, suggesting that the length of the SOCB is shorter in ON cells. Significance. This may have important implications for stimulation strategies in visual prostheses.

  9. Retinal bipolar cells: elementary building blocks of vision. (United States)

    Euler, Thomas; Haverkamp, Silke; Schubert, Timm; Baden, Tom


    Retinal bipolar cells are the first ‘projection neurons’ of the vertebrate visual system—all of the information needed for vision is relayed by this intraretinal connection. Each of the at least 13 distinct types of bipolar cells systematically transforms the photoreceptor input in a different way, thereby generating specific channels that encode stimulus properties, such as polarity, contrast, temporal profile and chromatic composition. As a result, bipolar cell output signals represent elementary ‘building blocks’ from which the microcircuits of the inner retina derive a feature-oriented description of the visual world.

  10. Apricot melanoidins prevent oxidative endothelial cell death by counteracting mitochondrial oxidation and membrane depolarization.

    Directory of Open Access Journals (Sweden)

    Annalisa Cossu

    Full Text Available The cardiovascular benefits associated with diets rich in fruit and vegetables are thought to be due to phytochemicals contained in fresh plant material. However, whether processed plant foods provide the same benefits as unprocessed ones is an open question. Melanoidins from heat-processed apricots were isolated and their presence confirmed by colorimetric analysis and browning index. Oxidative injury of endothelial cells (ECs is the key step for the onset and progression of cardiovascular diseases (CVD, therefore the potential protective effect of apricot melanoidins on hydrogen peroxide-induced oxidative mitochondrial damage and cell death was explored in human ECs. The redox state of cytoplasmic and mitochondrial compartments was detected by using the redox-sensitive, fluorescent protein (roGFP, while the mitochondrial membrane potential (MMP was assessed with the fluorescent dye, JC-1. ECs exposure to hydrogen peroxide, dose-dependently induced mitochondrial and cytoplasmic oxidation. Additionally detected hydrogen peroxide-induced phenomena were MMP dissipation and ECs death. Pretreatment of ECs with apricot melanoidins, significantly counteracted and ultimately abolished hydrogen peroxide-induced intracellular oxidation, mitochondrial depolarization and cell death. In this regard, our current results clearly indicate that melanoidins derived from heat-processed apricots, protect human ECs against oxidative stress.

  11. Intercellular K⁺ accumulation depolarizes Type I vestibular hair cells and their associated afferent nerve calyx. (United States)

    Contini, D; Zampini, V; Tavazzani, E; Magistretti, J; Russo, G; Prigioni, I; Masetto, S


    Mammalian vestibular organs contain two types of sensory receptors, named Type I and Type II hair cells. While Type II hair cells are contacted by several small afferent nerve terminals, the basolateral surface of Type I hair cells is almost entirely enveloped by a single large afferent nerve terminal, called calyx. Moreover Type I, but not Type II hair cells, express a low-voltage-activated outward K(+) current, I(K,L), which is responsible for their much lower input resistance (Rm) at rest as compared to Type II hair cells. The functional meaning of I(K,L) and associated calyx is still enigmatic. By combining the patch-clamp whole-cell technique with the mouse whole crista preparation, we have recorded the current- and voltage responses of in situ hair cells. Outward K(+) current activation resulted in K(+) accumulation around Type I hair cells, since it induced a rightward shift of the K(+) reversal potential the magnitude of which depended on the amplitude and duration of K(+) current flow. Since this phenomenon was never observed for Type II hair cells, we ascribed it to the presence of a residual calyx limiting K(+) efflux from the synaptic cleft. Intercellular K(+) accumulation added a slow (τ>100ms) depolarizing component to the cell voltage response. In a few cases we were able to record from the calyx and found evidence for intercellular K(+) accumulation as well. The resulting depolarization could trigger a discharge of action potentials in the afferent nerve fiber. Present results support a model where pre- and postsynaptic depolarization produced by intercellular K(+) accumulation cooperates with neurotransmitter exocytosis in sustaining afferent transmission arising from Type I hair cells. While vesicular transmission together with the low Rm of Type I hair cells appears best suited for signaling fast head movements, depolarization produced by intercellular K(+) accumulation could enhance signal transmission during slow head movements. Copyright

  12. Nicotine-evoked cytosolic Ca2+ increase and cell depolarization in capillary endothelial cells of the bovine adrenal medulla

    Directory of Open Access Journals (Sweden)



    Full Text Available Endothelial cells are directly involved in many functions of the cardiovascular system by regulating blood flow and blood pressure through Ca2+ dependent exocitosis of vasoactive compounds. Using the Ca2+ indicator Fluo-3 and the patch-clamp technique, we show that bovine adrenal medulla capillary endothelial cells (B AMCECs respond to acetylcholine (ACh with a cytosolic Ca2+ increase and depolarization of the membrane potential (20.3±0.9 mV; n=23. The increase in cytosolic Ca2+ induced by 10µM ACh was mimicked by the same concentration of nicotine but not by muscarine and was blocked by 100 µM of hexamethonium. On the other hand, the increase in cytosolic Ca2+ could be depressed by nifedipine (0.01 -100 µM or withdrawal of extracellular Ca2+. Taken together, these results give evidence for functional nicotinic receptors (nAChRs in capillary endothelial cells of the adrenal medulla. It suggests that nAChRs in B AMCECs may be involved in the regulation of the adrenal gland's microcirculation by depolarizing the membrane potential, leading to the opening of voltage-activated Ca2+ channels, influx of external Ca2+ and liberation of vasoactive compounds.

  13. Composite Bipolar Plate for Unitized Fuel Cell/Electrolyzer Systems (United States)

    Mittelsteadt, Cortney K.; Braff, William


    In a substantial improvement over present alkaline systems, an advanced hybrid bipolar plate for a unitized fuel cell/electrolyzer has been developed. This design, which operates on pure feed streams (H2/O2 and water, respectively) consists of a porous metallic foil filled with a polymer that has very high water transport properties. Combined with a second metallic plate, the pore-filled metallic plates form a bipolar plate with an empty cavity in the center.

  14. PEM fuel cell bipolar plate material requirements for transportation applications

    Energy Technology Data Exchange (ETDEWEB)

    Borup, R.L.; Stroh, K.R.; Vanderborgh, N.E. [Los Alamos National Lab., NM (United States)] [and others


    Cost effective bipolar plates are currently under development to help make proton exchange membrane (PEM) fuel cells commercially viable. Bipolar plates separate individual cells of the fuel cell stack, and thus must supply strength, be electrically conductive, provide for thermal control of the fuel stack, be a non-porous materials separating hydrogen and oxygen feed streams, be corrosion resistant, provide gas distribution for the feed streams and meet fuel stack cost targets. Candidate materials include conductive polymers and metal plates with corrosion resistant coatings. Possible metals include aluminium, titanium, iron/stainless steel and nickel.

  15. Design of metallic bipolar plates for PEM fuel cells. (United States)


    This project focused on the design and production of metallic bipolar plates for use in PEM fuel cells. Different metals were explored : and stainless steel was found out to be best suited to our purpose. Following the selection of metal, it was calc...

  16. Rising Intracellular Zinc by Membrane Depolarization and Glucose in Insulin-Secreting Clonal HIT-T15 Beta Cells

    Directory of Open Access Journals (Sweden)

    Kira G. Slepchenko


    Full Text Available Zinc (Zn2+ appears to be intimately involved in insulin metabolism since insulin secretion is correlated with zinc secretion in response to glucose stimulation, but little is known about the regulation of zinc homeostasis in pancreatic beta-cells. This study set out to identify the intracellular zinc transient by imaging free cytosolic zinc in HIT-T15 beta-cells with fluorescent zinc indicators. We observed that membrane depolarization by KCl (30–60 mM was able to induce a rapid increase in cytosolic concentration of zinc. Multiple zinc transients of similar magnitude were elicited during repeated stimulations. The amplitude of zinc responses was not affected by the removal of extracellular calcium or zinc. However, the half-time of the rising slope was significantly slower after removing extracellular zinc with zinc chelator CaEDTA, suggesting that extracellular zinc affect the initial rising phase of zinc response. Glucose (10 mM induced substantial and progressive increases in intracellular zinc concentration in a similar way as KCl, with variation in the onset and the duration of zinc mobilization. It is known that the depolarization of beta-cell membrane is coupled with the secretion of insulin. Rising intracellular zinc concentration may act as a critical signaling factor in insulin metabolism of pancreatic beta-cells.

  17. Rising intracellular zinc by membrane depolarization and glucose in insulin-secreting clonal HIT-T15 beta cells. (United States)

    Slepchenko, Kira G; Li, Yang V


    Zinc (Zn(2+)) appears to be intimately involved in insulin metabolism since insulin secretion is correlated with zinc secretion in response to glucose stimulation, but little is known about the regulation of zinc homeostasis in pancreatic beta-cells. This study set out to identify the intracellular zinc transient by imaging free cytosolic zinc in HIT-T15 beta-cells with fluorescent zinc indicators. We observed that membrane depolarization by KCl (30-60 mM) was able to induce a rapid increase in cytosolic concentration of zinc. Multiple zinc transients of similar magnitude were elicited during repeated stimulations. The amplitude of zinc responses was not affected by the removal of extracellular calcium or zinc. However, the half-time of the rising slope was significantly slower after removing extracellular zinc with zinc chelator CaEDTA, suggesting that extracellular zinc affect the initial rising phase of zinc response. Glucose (10 mM) induced substantial and progressive increases in intracellular zinc concentration in a similar way as KCl, with variation in the onset and the duration of zinc mobilization. It is known that the depolarization of beta-cell membrane is coupled with the secretion of insulin. Rising intracellular zinc concentration may act as a critical signaling factor in insulin metabolism of pancreatic beta-cells.

  18. Bipolar membranes in forward bias region for fuel cell reactors

    International Nuclear Information System (INIS)

    Lobyntseva, Elena; Kallio, Tanja; Kontturi, Kyoesti


    Three bipolar membranes, two home-made composed of commercial cation (DuPont) and anion (FuMA-Tech) exchange membranes (called Nafion/FT-FAA and Nafion/FT-FAS) and a commercial one, BP-1 from FuMA-Tech, were investigated in order to characterize their suitability to use in a H 2 /O 2 fuel cell intended to produce hydrogen peroxide on the cathode instead of water. The Nafion/FT-FAA and Nafion/FT-FAS membranes were prepared using a hot-pressing method. The optimal hot-pressing conditions were determined by measuring the ionic conductivity of the membranes. The latter was observed to depend on the relative humidity of the bipolar membrane. Of the studied bipolar membranes, Nafion/FT-FAA showed the best performance. The transport number of protons measured in a concentration cell was observed to depend on the direction of the proton diffusion flux through these membranes so that transport numbers of ca. unity were obtained when the cation exchange side faced the solution with higher proton concentration. In the opposite case, when the higher concentration faced anion exchange side, the transport number of proton was clearly lower, indicating the usefulness of the bipolar membranes for hydrogen peroxide production in the fuel cell

  19. Alternative bipolar plates design and manufacturing for PEM fuel cell

    International Nuclear Information System (INIS)

    Lee Chang Chuan; Norhamidi Muhamad; Jaafar Sahari


    Bipolar plates is one of the important components in fuel cell stack, it comprise up to 80% of the stack volume. Traditionally, these plates have been fabricated from graphite, owing to its chemical nobility, and high electrical and thermal conductivity; but these plates are brittle and relatively thick. Therefore increasing the stack volume and size. Alternatives to graphite are carbon-carbon composite, carbon-polymer composite and metal (aluminum, stainless steel, titanium and nickel based alloy). The use of coated and uncoated metal bipolar plates has received attention recently due to the simplicity of plate manufacturing. The thin nature of the metal substrate allows for smaller stack design with reduced weight. Lightweight coated metals as alternative to graphite plate is being developed. Beside the traditional method of machining and slurry molding, metal foam for bipolar plates fabrication seems to be a good alternative. The plates will be produced with titanium powder by Powder Metallurgy method using space holders technique to produce the meal foam flow-field. This work intends to facilitate the materials and manufacturing process requirements to produce cost effective foamed bipolar plates for fuel cell

  20. Acetylcholine induces GABA release onto rod bipolar cells through heteromeric nicotinic receptors expressed in A17 amacrine cells. (United States)

    Elgueta, Claudio; Vielma, Alex H; Palacios, Adrian G; Schmachtenberg, Oliver


    Acetylcholine (ACh) is a major retinal neurotransmitter that modulates visual processing through a large repertoire of cholinergic receptors expressed on different retinal cell types. ACh is released from starburst amacrine cells (SACs) under scotopic conditions, but its effects on cells of the rod pathway have not been investigated. Using whole-cell patch clamp recordings in slices of rat retina, we found that ACh application triggers GABA release onto rod bipolar (RB) cells. GABA was released from A17 amacrine cells and activated postsynaptic GABAA and GABAC receptors in RB cells. The sensitivity of ACh-induced currents to nicotinic ACh receptor (nAChR) antagonists (TMPH ~ mecamylamine > erysodine > DhβE > MLA) together with the differential potency of specific agonists to mimic ACh responses (cytisine > RJR2403 ~ choline), suggest that A17 cells express heteromeric nAChRs containing the β4 subunit. Activation of nAChRs induced GABA release after Ca(2+) accumulation in A17 cell dendrites and varicosities mediated by L-type voltage-gated calcium channels (VGCCs) and intracellular Ca(2+) stores. Inhibition of acetylcholinesterase depolarized A17 cells and increased spontaneous inhibitory postsynaptic currents in RB cells, indicating that endogenous ACh enhances GABAergic inhibition of RB cells. Moreover, injection of neostigmine or cytisine reduced the b-wave of the scotopic flash electroretinogram (ERG), suggesting that cholinergic modulation of GABA release controls RB cell activity in vivo. These results describe a novel regulatory mechanism of RB cell inhibition and complement our understanding of the neuromodulatory control of retinal signal processing.

  1. ON Cone Bipolar Cell Axonal Synapses in the OFF Inner Plexiform Layer of the Rabbit Retina (United States)

    Lauritzen, J. Scott; Anderson, James R.; Jones, Bryan W.; Watt, Carl B.; Mohammed, Shoeb; Hoang, John V.; Marc, Robert E.


    Analysis of the rabbit retinal connectome RC1 reveals that the division between the ON and OFF inner plexiform layer (IPL) is not structurally absolute. ON cone bipolar cells make non-canonical axonal synapses onto specific targets and receive amacrine cell synapses in the nominal OFF layer, creating novel motifs, including inhibitory crossover networks. Automated transmission electron microscope (ATEM) imaging, molecular tagging, tracing, and rendering of ≈ 400 bipolar cells reveals axonal ribbons in 36% of ON cone bipolar cells, throughout the OFF IPL. The targets include GABA-positive amacrine cells (γACs), glycine-positive amacrine cells (GACs) and ganglion cells. Most ON cone bipolar cell axonal contacts target GACs driven by OFF cone bipolar cells, forming new architectures for generating ON-OFF amacrine cells. Many of these ON-OFF GACs target ON cone bipolar cell axons, ON γACs and/or ON-OFF ganglion cells, representing widespread mechanisms for OFF to ON crossover inhibition. Other targets include OFF γACs presynaptic to OFF bipolar cells, forming γAC-mediated crossover motifs. ON cone bipolar cell axonal ribbons drive bistratified ON-OFF ganglion cells in the OFF layer and provide ON drive to polarity-appropriate targets such as bistratified diving ganglion cells (bsdGCs). The targeting precision of ON cone bipolar cell axonal synapses shows that this drive incidence is necessarily a joint distribution of cone bipolar cell axonal frequency and target cell trajectories through a given volume of the OFF layer. Such joint distribution sampling is likely common when targets are sparser than sources and when sources are coupled, as are ON cone bipolar cells. PMID:23042441

  2. Does bipolar pacemaker current activate blood platelets?

    DEFF Research Database (Denmark)

    Gjesdal, Grunde; Hansen, Annebirthe Bo; Brandes, Axel


    OBJECTIVE: The aim of this study was to investigate whether bipolar pacemaker current lead can activate blood platelets. The null hypothesis was that 1 minute of electrical stimulation of platelets would not influence their subsequent reactivity to adenosine diphosphate (ADP). BACKGROUND: Both...... platelets and muscle cells contain actin and myosin filaments, and both cells are activated following calcium influx. Muscle cells open their calcium channels and contract when exposed to an electric current. Current through a bipolar pacemaker lead will expose a small volume of blood, including platelets......, to the depolarizing current. Platelet activation may ensue, resulting in aggregation, release reaction, and contraction. In contrast, a unipolar pacemaker system will not depolarize blood, but transmit current directly into the myocardium, and the current afterward passes through other tissues before returning...

  3. Oxytocin Depolarizes Fast-Spiking Hilar Interneurons and Induces GABA Release onto Mossy Cells of the Rat Dentate Gyrus (United States)

    Harden, Scott W.; Frazier, Charles J.


    Delivery of exogenous oxytocin (OXT) to central oxytocin receptors (OXT-Rs) is currently being investigated as a potential treatment for conditions such as post-traumatic stress disorder (PTSD), depression, social anxiety, and autism spectrum disorder (ASD). Despite significant research implicating central OXT signaling in modulation of mood, affect, social behavior, and stress response, relatively little is known about the cellular and synaptic mechanisms underlying these complex actions, particularly in brain regions which express the OXT-R but lie outside of the hypothalamus (where OXT-synthesizing neurons reside). We report that bath application of low concentrations of the selective OXT-R agonist Thr4,Gly7-OXT (TGOT) reliably and robustly drives GABA release in the dentate gyrus in an action potential dependent manner. Additional experiments led to identification of a small subset of small hilar interneurons that are directly depolarized by acute application of TGOT. From a physiological perspective, TGOT-responsive hilar interneurons have high input resistance, rapid repolarization velocity during an action potential, and a robust afterhyperpolarization. Further, they fire irregularly (or stutter) in response to moderate depolarization, and fire quickly with minimal spike frequency accommodation in response to large current injections. From an anatomical perspective, TGOT responsive hilar interneurons have dense axonal arborizations in the hilus that were found close proximity with mossy cell somata and/or proximal dendrites, and also invade the granule cell layer. Further, they have primary dendrites that always extend into the granule cell layer, and sometimes have clear arborizations in the molecular layer. Overall, these data reveal a novel site of action for OXT in an important limbic circuit, and represent a significant step towards better understanding how endogenous OXT may modulate flow of information in hippocampal networks. PMID:27068005

  4. Achiral Mannich-Base Curcumin Analogs Induce Unfolded Protein Response and Mitochondrial Membrane Depolarization in PANC-1 Cells

    Directory of Open Access Journals (Sweden)

    Gábor J. Szebeni


    Full Text Available Achiral Mannich-type curcumin analogs have been synthetized and assayed for their cytotoxic activity. The anti-proliferative and cytotoxic activity of curcuminoids has been tested on human non-small-cell lung carcinoma (A549, hepatocellular carcinoma (HepG2 and pancreatic cancer cell line (PANC-1. Based on the highest anti-proliferative activity nine drug candidates were further tested and proved to cause phosphatidylserine exposure as an early sign of apoptosis. Curcumin analogs with the highest apoptotic activity were selected for mechanistic studies in the most sensitive PANC-1 cells. Cytotoxic activity was accompanied by cytostatic effect since curcumin and analogs treatment led to G0/G1 cell cycle arrest. Moreover, cytotoxic effect could be also detected via the accumulation of curcuminoids in the endoplasmic reticulum (ER and the up-regulation of ER stress-related unfolded protein response (UPR genes: HSPA5, ATF4, XBP1, and DDIT3. The activated UPR induced mitochondrial membrane depolarization, caspase-3 activation and subsequent DNA breakdown in PANC-1 cells. Achiral curcumin analogs, C509, C521 and C524 possessed superior, 40-times more potent cytotoxic activity compared to natural dihydroxy-dimetoxycurcumin in PANC-1 cells.

  5. Achiral Mannich-Base Curcumin Analogs Induce Unfolded Protein Response and Mitochondrial Membrane Depolarization in PANC-1 Cells. (United States)

    Szebeni, Gábor J; Balázs, Árpád; Madarász, Ildikó; Pócz, Gábor; Ayaydin, Ferhan; Kanizsai, Iván; Fajka-Boja, Roberta; Alföldi, Róbert; Hackler, László; Puskás, László G


    Achiral Mannich-type curcumin analogs have been synthetized and assayed for their cytotoxic activity. The anti-proliferative and cytotoxic activity of curcuminoids has been tested on human non-small-cell lung carcinoma (A549), hepatocellular carcinoma (HepG2) and pancreatic cancer cell line (PANC-1). Based on the highest anti-proliferative activity nine drug candidates were further tested and proved to cause phosphatidylserine exposure as an early sign of apoptosis. Curcumin analogs with the highest apoptotic activity were selected for mechanistic studies in the most sensitive PANC-1 cells. Cytotoxic activity was accompanied by cytostatic effect since curcumin and analogs treatment led to G₀/G₁ cell cycle arrest. Moreover, cytotoxic effect could be also detected via the accumulation of curcuminoids in the endoplasmic reticulum (ER) and the up-regulation of ER stress-related unfolded protein response (UPR) genes: HSPA5 , ATF4, XBP1 , and DDIT3 . The activated UPR induced mitochondrial membrane depolarization, caspase-3 activation and subsequent DNA breakdown in PANC-1 cells. Achiral curcumin analogs, C509, C521 and C524 possessed superior, 40-times more potent cytotoxic activity compared to natural dihydroxy-dimetoxycurcumin in PANC-1 cells.

  6. Transitory endolymph leakage induced hearing loss and tinnitus: depolarization, biphasic shortening and loss of electromotility of outer hair cells (United States)

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


    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.

  7. Elevated hydrostatic pressures induce apoptosis and oxidative stress through mitochondrial membrane depolarization in PC12 neuronal cells: A cell culture model of glaucoma. (United States)

    Tök, Levent; Nazıroğlu, Mustafa; Uğuz, Abdülhadi Cihangir; Tök, Ozlem


    Despite the importance of oxidative stress and apoptosis through mitochondrial depolarization in neurodegenerative diseases, their roles in etiology of glaucoma are poorly understood. We aimed to investigate whether oxidative stress and apoptosis formation are altered in rat pheochromocytoma-derived cell line-12 (PC12) neuronal cell cultures exposed to elevated different hydrostatic pressures as a cell culture model of glaucoma. Cultured PC12 cells were subjected to 0, 15 and 70 mmHg hydrostatic pressure for 1 and 24 h. Then, the following values were analyzed: (a) cell viability; (b) lipid peroxidation and intracellular reactive oxygen species production; (c) mitochondrial membrane depolarization; (d) cell apoptosis; (e) caspase-3 and caspase-9 activities; (f) reduced glutathione (GSH) and glutathione peroxidase (GSH-Px). The hydrostatic pressures (15 and 70 mmHg) increased oxidative cell damage through a decrease of GSH and GSH-Px values, and increasing mitochondrial membrane potential. Additionally, 70 mmHg hydrostatic pressure for 24 h indicated highest apoptotic effects, as demonstrated by plate reader analyses of apoptosis, caspase-3 and -9 values. The present data indicated oxidative stress, apoptosis and mitochondrial changes in PC12 cell line during different hydrostatic pressure as a cell culture model of glaucoma. This findings support the view that mitochondrial oxidative injury contributes early to glaucomatous optic neuropathy.

  8. Bipolar Cell-Photoreceptor Connectivity in the Zebrafish (Danio rerio) Retina (United States)

    Li, Yong N.; Tsujimura, Taro; Kawamura, Shoji; Dowling, John E.


    Bipolar cells convey luminance, spatial and color information from photoreceptors to amacrine and ganglion cells. We studied the photoreceptor connectivity of 321 bipolar cells in the adult zebrafish retina. 1,1'-Dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) was inserted into whole-mounted transgenic zebrafish retinas to label bipolar cells. The photoreceptors that connect to these DiI-labeled cells were identified by transgenic fluorescence or their positions relative to the fluorescent cones, as cones are arranged in a highly-ordered mosaic: rows of alternating blue- (B) and ultraviolet-sensitive (UV) single cones alternate with rows of red- (R) and green-sensitive (G) double cones. Rod terminals intersperse among cone terminals. As many as 18 connectivity subtypes were observed, 9 of which – G, GBUV, RG, RGB, RGBUV, RGRod, RGBRod, RGBUVRod and RRod bipolar cells – accounted for 96% of the population. Based on their axon terminal stratification, these bipolar cells could be further sub-divided into ON, OFF, and ON-OFF cells. The dendritic spread size, soma depth and size, and photoreceptor connections of the 308 bipolar cells within the 9 common connectivity subtypes were determined, and their dendritic tree morphologies and axonal stratification patterns compared. We found that bipolar cells with the same axonal stratification patterns could have heterogeneous photoreceptor connectivity whereas bipolar cells with the same dendritic tree morphology usually had the same photoreceptor connectivity, although their axons might stratify on different levels. PMID:22907678

  9. Quinuclidine compounds differently act as agonists of Kenyon cell nicotinic acetylcholine receptors and induced distinct effect on insect ganglionic depolarizations. (United States)

    Mathé-Allainmat, Monique; Swale, Daniel; Leray, Xavier; Benzidane, Yassine; Lebreton, Jacques; Bloomquist, Jeffrey R; Thany, Steeve H


    We have recently demonstrated that a new quinuclidine benzamide compound named LMA10203 acted as an agonist of insect nicotinic acetylcholine receptors. Its specific pharmacological profile on cockroach dorsal unpaired median neurons (DUM) helped to identify alpha-bungarotoxin-insensitive nAChR2 receptors. In the present study, we tested its effect on cockroach Kenyon cells. We found that it induced an inward current demonstrating that it bounds to nicotinic acetylcholine receptors expressed on Kenyon cells. Interestingly, LMA10203-induced currents were completely blocked by the nicotinic antagonist α-bungarotoxin. We suggested that LMA10203 effect occurred through the activation of α-bungarotoxin-sensitive receptors and did not involve α-bungarotoxin-insensitive nAChR2, previously identified in DUM neurons. In addition, we have synthesized two new compounds, LMA10210 and LMA10211, and compared their effects on Kenyon cells. These compounds were members of the 3-quinuclidinyl benzamide or benzoate families. Interestingly, 1 mM LMA10210 was not able to induce an inward current on Kenyon cells compared to LMA10211. Similarly, we did not find any significant effect of LMA10210 on cockroach ganglionic depolarization, whereas these three compounds were able to induce an effect on the central nervous system of the third instar M. domestica larvae. Our data suggested that these three compounds could bind to distinct cockroach nicotinic acetylcholine receptors.

  10. Low cost bipolar current collector-separator for electrochemical cells

    International Nuclear Information System (INIS)

    Lawrence, R.


    A bipolar current collecting, cell separating element for electrochemical cells for conducting current from the anode electrode of one cell unit to cathode electrode of the adjacent cell unit comprises: (A) a pressure mold aggregate of electrically conductive carbon/graphite particles and thermoplastic fluorocarbon polymer resin particles in a weight ratio of 2.5:1 to 16:1 whereby said molded aggregated has a bulk resistivity which is less than 4x10 -3 ohm/inch, (B) said molded aggregate having a fluid imprevious main body, at least one recessed chamber on one side of said main body and a plurality of spaced, conductive projections extending from the base of said chamber for contacting and permitting current flow between the electrode of adjacent cell unit, and (C) means communicating with said recessed chambers to permit introduction and removal of fluids

  11. Photovoltaic Cells Improvised With Used Bipolar Junction Transistors

    International Nuclear Information System (INIS)

    Akintayo, J. A


    The understanding of the underlying principle that the solar cell consists of a p-n junction is exploited to adapt the basic NPN or PNP Bipolar Junction Transistors (BJT) to serve as solar cells. In this mode the in improvised solar cell have employed just the emitter and the base sections with an intact emitter/base junction as the active PN area. The improvised devices tested screened and sorted are wired up in strings, blocks and modules. The photovoltaic modules realised tested as close replica of solar cells with output voltage following insolation level. Further work need be done on the modules to make them generate usable levels of output voltage and current

  12. CarbonNanoTubes (CNT) in bipolar plates for PEM fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Grundler, M.; Derieth, T.; Beckhaus, P.; Heinzel, A. [centre for fuel cell technology ZBT GmbH (Germany)


    Using standard mass production techniques for the fabrication of fuel cell components, such as bipolar plates, is a main issue for the commercialisation of PEM fuel cell systems. Bipolar plates contribute significantly to the cost structure of PEM stacks. In an upcoming fuel cell market a large number of bipolar plates with specific high-quality standards will be needed. At the Centre for Fuel Cell Technology (ZBT) together with the University of Duisburg-Essen fuel cell stacks based on injection moulded bipolar plates have been developed and demonstrated successfully [1]. This paper focuses on the interactions between carbon filling materials (graphite, carbon black and carbon nanotubes (CNT)) in compound based bipolar plates and especially the potential of CNTs, which were used in bipolar plates for the first time. The entire value added chain based on the feedstock, the compounding and injection moulding process, the component bipolar plate, up to the operation of a PEM single fuel cell stack with CNT-based bipolar plates is disclosed. (orig.)

  13. Bacterial Membrane Depolarization-Linked Fuel Cell Potential Burst as Signal for Selective Detection of Alcohol. (United States)

    Kaushik, Sharbani; Goswami, Pranab


    The biosensing application of microbial fuel cell (MFC) is hampered by its long response time, poor selectivity, and technical difficulty in developing portable devices. Herein, a novel signal form for rapid detection of ethanol was generated in a photosynthetic MFC (PMFC). First, a dual chambered (100 mL each) PMFC was fabricated by using cyanobacteria-based anode and abiotic cathode, and its performance was examined for detection of alcohols. A graphene-based nanobiocomposite matrix was layered over graphite anode to support cyanobacterial biofilm growth and to facilitate electron transfer. Injection of alcohols into the anodic chamber caused a transient potential burst of the PMFC within 60 s (load 1000 Ω), and the magnitude of potential could be correlated to the ethanol concentrations in the range 0.001-20% with a limit of detection (LOD) of 0.13% ( R 2 = 0.96). The device exhibited higher selectivity toward ethanol than methanol as discerned from the corresponding cell-alcohol interaction constant ( K i ) of 780 and 1250 mM. The concept was then translated to a paper-based PMFC (p-PMFC) (size ∼20 cm 2 ) wherein, the cells were merely immobilized over the anode. The device with a shelf life of ∼3 months detected ethanol within 10 s with a dynamic range of 0.005-10% and LOD of 0.02% ( R 2 = 0.99). The fast response time was attributed to the higher wettability of ethanol on the immobilized cell surface as validated by the contact angle data. Alcohols degraded the cell membrane on the order of ethanol > methanol, enhanced the redox current of the membrane-bound electron carrier proteins, and pushed the anodic band gap toward more negative value. The consequence was the potential burst, the magnitude of which was correlated to the ethanol concentrations. This novel approach has a great application potential for selective, sensitive, rapid, and portable detection of ethanol.

  14. Membrane depolarization increases ryanodine sensitivity to Ca2+ release to the cytosol in L6 skeletal muscle cells: Implications for excitation-contraction coupling. (United States)

    Pitake, Saumitra; Ochs, Raymond S


    The dihydropyridine receptor in the plasma membrane and the ryanodine receptor in the sarcoplasmic reticulum are known to physically interact in the process of excitation-contraction coupling. However, the mechanism for subsequent Ca(2+) release through the ryanodine receptor is unknown. Our lab has previously presented evidence that the dihydropyridine receptor and ryanodine receptor combine as a channel for the entry of Ca(2+) under resting conditions, known as store operated calcium entry. Here, we provide evidence that depolarization during excitation-contraction coupling causes the dihydropyridine receptor to disengage from the ryanodine receptor. The newly freed ryanodine receptor can then transport Ca(2+) from the sarcoplasmic reticulum to the cytosol. Experimentally, this should more greatly expose the ryanodine receptor to exogenous ryanodine. To examine this hypothesis, we titrated L6 skeletal muscle cells with ryanodine in resting and excited (depolarized) states. When L6 muscle cells were depolarized with high potassium or exposed to the dihydropyridine receptor agonist BAYK-8644, known to induce dihydropyridine receptor movement within the membrane, ryanodine sensitivity was enhanced. However, ryanodine sensitivity was unaffected when Ca(2+) was elevated without depolarization by the ryanodine receptor agonist chloromethylcresol, or by increasing Ca(2+) concentration in the media. Ca(2+) entry currents (from the extracellular space) during excitation were strongly inhibited by ryanodine, but Ca(2+) entry currents in the resting state were not. We conclude that excitation releases the ryanodine receptor from occlusion by the dihydropyridine receptor, enabling Ca(2+) release from the ryanodine receptor to the cytosol. © 2015 by the Society for Experimental Biology and Medicine.

  15. Pivotal roles of Fezf2 in differentiation of cone OFF bipolar cells and functional maturation of cone ON bipolar cells in retina. (United States)

    Suzuki-Kerr, Haruna; Iwagawa, Toshiro; Sagara, Hiroshi; Mizota, Atsushi; Suzuki, Yutaka; Watanabe, Sumiko


    During development of the retina, common retinal progenitor cells give rise to six classes of neurons that subsequently further diversify into more than 55 subtypes of neuronal subtypes. Here, we have investigated the expression and function of Fezf2, Fez zinc finger family of protein, in the developing mouse retina. Expression of Fezf2 transcripts was strongly observed in the embryonic retinal progenitors at E14.5 and declined quickly in subsequent development of retina. Then, in postnatal stage at around day 8, Fezf2 was transiently expressed then declined again. Loss-of-function analysis using retinas from mice in which Fezf2 coding region was substituted with β-galactosidase showed that Fezf2 is expressed in a subset of cone OFF bipolar cells and required for their differentiation. Using electroretinogram, we found that Fezf2 knockout retina exhibited significantly reduced photopic b-wave, suggesting functional abnormality of cone ON bipolar cells. Furthermore, reduced expression of synaptic protein Trpm1 and structural alteration of ON bipolar cell invagination, both of which affected cone photoreceptor terminal synaptic activity, was identified by transmission electron microscopy and immunohistochemistry, respectively. Taken together, our results show that Fezf2 is indispensable in differentiation of bipolar precursors into cone OFF bipolar cells and in functional maturation of cone ON bipolar cells during development of mouse retina. These results contribute to our understanding of how diversity of neuronal subtypes and hence specificity of neuronal connections are established in the retina by intrinsic cues. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Flow channel shape optimum design for hydroformed metal bipolar plate in PEM fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Linfa; Lai, Xinmin; Liu, Dong' an; Hu, Peng [State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240 (China); Ni, Jun [Department of Mechanical Engineering and Applied Mechanics, University of Michigan, Ann Arbor, MI 48109 (United States)


    Bipolar plate is one of the most important and costliest components of polymer electrolyte membrane (PEM) fuel cells. Micro-hydroforming is a promising process to reduce the manufacturing cost of PEM fuel cell bipolar plates made of metal sheets. As for hydroformed bipolar plates, the main defect is the rupture because of the thinning of metal sheet during the forming process. The flow channel section decides whether high quality hydroformed bipolar plates can be successively achieved or not. Meanwhile, it is also the key factor that is related with the reaction efficiency of the fuel cell stacks. In order to obtain the optimum flow channel section design prior the experimental campaign, some key geometric dimensions (channel depth, channel width, rib width and transition radius) of flow channel section, which are related with both reaction efficiency and formability, are extracted and parameterized as the design variables. By design of experiments (DOE) methods and an adoptive simulated annealing (ASA) optimization method, an optimization model of flow channel section design for hydroformed metal bipolar plate is proposed. Optimization results show that the optimum dimension values for channel depth, channel width, rib width and transition radius are 0.5, 1.0, 1. 6 and 0.5 mm, respectively with the highest reaction efficiency (79%) and the acceptable formability (1.0). Consequently, their use would lead to improved fuel cell efficiency for low cost hydroformed metal bipolar plates. (author)

  17. Neutron Depolarization in Superconductors (United States)

    Zhuchenko, N. K.


    The dependences of neutron depolarization on applied magnetic field are deduced along the magnetization hysteresis loop in terms of the Bean model of the critical state. The depolarization in uniaxial superconductors with the reversible magnetization, including uniaxial magnetic superconductors, is also considered. A strong depolarization is expected if the neutrons travel along the vortex lines. On calcule la dépendance en champ magnétique de la dépolarisation des neutrons le long du cycle d'hystérésis en termes du modèle critique de Bean. On considère aussi la dépolarisation dans les supraconducteurs uniaxiaux en fonction de l'aimantation réversible, y compris pour les supraconducteurs magnétiques. On attend une forte dépolarisation si les neutrons se propagent le long des vortex.

  18. Corrosion resistance characteristics of stamped and hydroformed proton exchange membrane fuel cell metallic bipolar plates

    Energy Technology Data Exchange (ETDEWEB)

    Dundar, F. [NSF I/UCRC Center for Precision Forming (CPF), Virginia Commonwealth University, Richmond, VA (United States); Department of Materials Science and Engineering, Gebze Institute of Technology (Turkey); Dur, Ender; Koc, M. [NSF I/UCRC Center for Precision Forming (CPF), Virginia Commonwealth University, Richmond, VA (United States); Mahabunphachai, S. [NSF I/UCRC Center for Precision Forming (CPF), Virginia Commonwealth University, Richmond, VA (United States); National Metal and Materials Technology Center (MTEC), Pathumthani (Thailand)


    Metallic bipolar plates have several advantages over bipolar plates made from graphite and composites due to their high conductivity, low material and production costs. Moreover, thin bipolar plates are possible with metallic alloys, and hence low fuel cell stack volume and mass are. Among existing fabrication methods for metallic bipolar plates, stamping and hydroforming are seen as prominent approaches for mass production scales. In this study, the effects of important process parameters of these manufacturing processes on the corrosion resistance of metallic bipolar plates made of SS304 were investigated. Specifically, the effects of punch speed, pressure rate, stamping force and hydroforming pressure were studied as they were considered to inevitably affect the bipolar plate micro-channel dimensions, surface topography, and hence the corrosion resistance. Corrosion resistance under real fuel cell conditions was examined using both potentiodynamic and potentiostatic experiments. The majority of the results exhibited a reduction in the corrosion resistance for both stamped and hydroformed plates when compared with non-deformed blank plates of SS304. In addition, it was observed that there exist an optimal process window for punch speed in stamping and the pressure rate in hydroforming to achieve improved corrosion resistance at a faster production rate. (author)

  19. Induction of necrosis and apoptosis to KB cancer cells by sanguinarine is associated with reactive oxygen species production and mitochondrial membrane depolarization

    International Nuclear Information System (INIS)

    Chang, M.-C.; Chan, C.-P.; Wang, Y.-J.; Lee, P.-H.; Chen, L.-I; Tsai, Y.-L.; Lin, B.-R.; Wang, Y.-L.; Jeng, J.-H.


    Sanguinarine is a benzopheanthridine alkaloid present in the root of Sanguinaria canadensis L. and Chellidonium majus L. In this study, sanguinarine (2 and 3 μM) exhibited cytotoxicity to KB cancer cells by decreasing MTT reduction to 83% and 52% of control after 24-h of exposure. Sanguinarine also inhibited the colony forming capacity (> 52-58%) and growth of KB cancer cells at concentrations higher than 0.5-1 μM. Short-term exposure to sanguinarine (> 0.5 μM) effectively suppressed the adhesion of KB cells to collagen and fibronectin (FN). Sanguinarine (2 and 3 μM) induced evident apoptosis as indicated by an increase in sub-G0/G1 populations, which was detected after 6-h of exposure. Only a slight increase in cells arresting in S-phase and G2/M was noted. Induction of KB cell apoptosis and necrosis by sanguinarine (2 and 3 μM) was further confirmed by Annexin V-PI dual staining flow cytometry and the presence of DNA fragmentation. The cytotoxicity by sanguinarine was accompanied by an increase in production of reactive oxygen species (ROS) and depolarization of mitochondrial membrane potential as indicated by single cell flow cytometric analysis of DCF and rhodamine fluorescence. NAC (1 and 3 mM) and catalase (2000 U/ml) prevented the sanguinarine-induced ROS production and cytotoxicity, whereas dimethylthiourea (DMT) showed no marked preventive effect. These results suggest that sanguinarine has anticarcinogenic properties with induction of ROS production and mitochondrial membrane depolarization, which mediate cancer cell death

  20. Age-related decrease in rod bipolar cell density of the human retina ...

    Indian Academy of Sciences (India)


    Retinal bipolar cells situated in the inner nuclear layer are predominantly involved in mediating the transfer of signals from the photoreceptors to the ganglion cells. Their synapses are located both at the level of the outer and inner plexiform layers. In the former, their dendritic processes synapse with photoreceptors in the ...

  1. Corrosion of metal bipolar plates for PEM fuel cells: A review

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, Renato A. [Engenharia de Materiais, Universidade Federal do ABC (UFABC), 09210-170 Santo Andre, SP (Brazil); Oliveira, Mara Cristina L.; Ett, Gerhard; Ett, Volkmar [Electrocell Ind. Com. Equip. Elet. LTDA, Centro de Inovacao, Empreendedorismo e Tecnologia (CIETEC), 05508-000 Sao Paulo, SP (Brazil)


    PEM fuel cells are of prime interest in transportation applications due to their relatively high efficiency and low pollutant emissions. Bipolar plates are the key components of these devices as they account for significant fractions of their weight and cost. Metallic materials have advantages over graphite-based ones because of their higher mechanical strength and better electrical conductivity. However, corrosion resistance is a major concern that remains to be solved as metals may develop oxide layers that increase electrical resistivity, thus lowering the fuel cell efficiency. This paper aims to present the main results found in recent literature about the corrosion performance of metallic bipolar plates. (author)

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

    DEFF Research Database (Denmark)

    Dreier, Jens P; Major, Sebastian; Pannek, Heinz-Wolfgang


    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...... 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...

  3. Highly conductive composites for fuel cell flow field plates and bipolar plates (United States)

    Jang, Bor Z; Zhamu, Aruna; Song, Lulu


    This invention provides a fuel cell flow field plate or bipolar plate having flow channels on faces of the plate, comprising an electrically conductive polymer composite. The composite is composed of (A) at least 50% by weight of a conductive filler, comprising at least 5% by weight reinforcement fibers, expanded graphite platelets, graphitic nano-fibers, and/or carbon nano-tubes; (B) polymer matrix material at 1 to 49.9% by weight; and (C) a polymer binder at 0.1 to 10% by weight; wherein the sum of the conductive filler weight %, polymer matrix weight % and polymer binder weight % equals 100% and the bulk electrical conductivity of the flow field or bipolar plate is at least 100 S/cm. The invention also provides a continuous process for cost-effective mass production of the conductive composite-based flow field or bipolar plate.

  4. Charge separation in excitonic and bipolar solar cells - A detailed balance approach

    International Nuclear Information System (INIS)

    Kirchartz, Thomas; Rau, Uwe


    A generalized solar cell model for excitonic and classical, bipolar solar cells is developed that describes the combined transport and interaction of electrons, holes and excitons. Both, conventional inorganic solar cells as well as organic solar cells, where excitons play a dominant role for energy transport, turn out to be special cases of this model. Due to the inclusion of photon recycling effects, the approach is compatible with the principle of detailed balance and the Shockley-Queisser limit. We show how varying the interaction between excitons and charge carriers as well as varying the respective mobilities of the different species changes the operation mode of the solar cell path between excitonic and bipolar

  5. SEU-hardened silicon bipolar and GaAs MESFET SRAM cells using local redundancy techniques

    International Nuclear Information System (INIS)

    Hauser, J.R.


    Silicon bipolar and GaAs FET SRAM's have proven to be more difficult to harden with respect to single-event upset mechanisms than have silicon CMOS SRAM's. This is a fundamental property of bipolar and JFET or MESFET device technologies which do not have a high-impedance, nonactive isolation between the control electrode and the current or voltage being controlled. All SEU circuit level hardening techniques applied at the local level must use some type of information storage redundancy so that information loss on one node due to an SEU event can be recovered from information stored elsewhere in the cell. In CMOS technologies, this can be achieved by the use of simple cross-coupling resistors, whereas in bipolar and FET technologies, no such simple approach is possible. Several approaches to the use of local redundancy in bipolar and FET technologies are discussed in this paper. At the expense of increased cell complexity and increased power consumption and write time, several approaches are capable of providing complete SEU hardness at the local cell level

  6. Nanosecond pulsed electric fields depolarize transmembrane potential via voltage-gated K+, Ca2+ and TRPM8 channels in U87 glioblastoma cells. (United States)

    Burke, Ryan C; Bardet, Sylvia M; Carr, Lynn; Romanenko, Sergii; Arnaud-Cormos, Delia; Leveque, Philippe; O'Connor, Rodney P


    Nanosecond pulsed electric fields (nsPEFs) have a variety of applications in the biomedical and biotechnology industries. Cancer treatment has been at the forefront of investigations thus far as nsPEFs permeabilize cellular and intracellular membranes leading to apoptosis and necrosis. nsPEFs may also influence ion channel gating and have the potential to modulate cell physiology without poration of the membrane. This phenomenon was explored using live cell imaging and a sensitive fluorescent probe of transmembrane voltage in the human glioblastoma cell line, U87 MG, known to express a number of voltage-gated ion channels. The specific ion channels involved in the nsPEF response were screened using a membrane potential imaging approach and a combination of pharmacological antagonists and ion substitutions. It was found that a single 10ns pulsed electric field of 34kV/cm depolarizes the transmembrane potential of cells by acting on specific voltage-sensitive ion channels; namely the voltage and Ca2 + gated BK potassium channel, L- and T-type calcium channels, and the TRPM8 transient receptor potential channel. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Tenuifolide B from Cinnamomum tenuifolium Stem Selectively Inhibits Proliferation of Oral Cancer Cells via Apoptosis, ROS Generation, Mitochondrial Depolarization, and DNA Damage. (United States)

    Chen, Chung-Yi; Yen, Ching-Yu; Wang, Hui-Ru; Yang, Hui-Ping; Tang, Jen-Yang; Huang, Hurng-Wern; Hsu, Shih-Hsien; Chang, Hsueh-Wei


    oral cancer cells through apoptosis, ROS generation, mitochondrial membrane depolarization, and DNA damage.

  8. Process for production of electrical energy from the neutralization of acid and base in a bipolar membrane cell

    International Nuclear Information System (INIS)

    Walther, J.F.


    Electrical energy is generated from acid-base neutralization reactions in electrodialytic cells. Permselective bipolar membranes in these cells are contacted on their cation selective faces by aqueous acid streams and on their anion-selective faces by aqueous base streams. Spontaneous neutralization reactions between the basic anions and acidic cations through the bipolar membranes produce electrical potential differences between the acid and base streams. These potential differences are transmitted to electrodes to produce electrical energy which is withdrawn from the cell

  9. ON Bipolar Cells in Macaque Retina: Type-Specific Synaptic Connectivity with Special Reference to OFF Counterparts (United States)

    Tsukamoto, Yoshihiko; Omi, Naoko


    To date, 12 macaque bipolar cell types have been described. This list includes all morphology types first outlined by Polyak (1941) using the Golgi method in the primate retina and subsequently identified by other researchers using electron microscopy (EM) combined with the Golgi method, serial section transmission EM (SSTEM), and immunohistochemical imaging. We used SSTEM for the rod-dense perifoveal area of macaque retina, reconfirmed ON (cone) bipolar cells to be classified as invaginating midget bipolar (IMB), diffuse bipolar (DB)4, DB5, DB6, giant bipolar (GB), and blue bipolar (BB) types, and clarified their type-specific connectivity. DB4 cells made reciprocal synapses with a kind of ON-OFF lateral amacrine cell, similar to OFF DB2 cells. GB cells contacted rods and cones, similar to OFF DB3b cells. Retinal circuits formed by GB and DB3b cells are thought to substantiate the psychophysical finding of fast rod signals in mesopic vision. DB6 cell output synapses were directed to ON midget ganglion (MG) cells at 70% of ribbon contacts, similar to OFF DB1 cells that directed 60% of ribbon contacts to OFF MG cells. IMB cells contacted medium- or long-wavelength sensitive (M/L-) cones but not short-wavelength sensitive (S-) cones, while BB cells contacted S-cones but not M/L-cones. However, IMB and BB dendrites had similar morphological architectures, and a BB cell contacting a single S-cone resembled an IMB cell. Thus, both IMB and BB may be the ON bipolar counterparts of the OFF flat midget bipolar (FMB) type, likewise DB4 of DB2, DB5 of DB3a, DB6 of DB1, and GB of DB3b OFF bipolar type. The ON DB plus GB, and OFF DB cells predominantly contacted M/L-cones and their outputs were directed mainly to parasol ganglion (PG) cells but also moderately to MG cells. BB cells directed S-cone-driven outputs almost exclusively to small bistratified ganglion (SBG) cells. Some FMB cells predominantly contacted S-cones and their outputs were directed to OFF MG cells. Thus, two

  10. Nicotinic receptors and functional regulation of GABA cell microcircuitry in bipolar disorder and schizophrenia. (United States)

    Benes, Francine M


    Studies of the hippocampus in postmortem brains from patients with schizophrenia and bipolar disorder have provided evidence for a defect of GABAergic interneurons. Significant decreases in the expression of GAD67, a marker for GABA cell function, have been found repeatedly in several different brain regions that include the hippocampus. In this region, nicotinic receptors are thought to play an important role in modulating the activity of GABAergic interneurons by influences of excitatory cholinergic afferents on their activity. In bipolar disorder, this influence appears to be particularly prominent in the stratum oriens of sectors CA3/2 and CA1, two sites where these cells constitute the exclusive neuronal cell type. In sector CA3/2, this layer receives a robust excitatory projection from the basolateral amygdala (BLA) and this is thought to play a central role in regulating GABA cells at this locus. Using laser microdissection, recent studies have focused selectively on these two layers and their associated GABA cells using microarray technology. The results have provided support for the idea that nicotinic cholinergic receptors play a particularly important role in regulating the activity of GABA neurons at these loci by regulating the progression of cell cycle and the repair of damaged DNA. In bipolar disorder, there is a prominent reduction in the expression of mRNAs for several different nicotinic subunit isoforms. These decreases could reflect a diminished influence of this receptor system on these GABA cells, particularly in sector CA3/2 where a preponderance of abnormalities have been observed in postmortem studies. In patients with bipolar disorder, excitatory nicotinic cholinergic fibers from the medial septum may converge with glutamatergic fibers from the BLA on GABAergic interneurons in the stratum oriens of CA3/2 and result in disturbances of their genomic and functional integrity, ones that may induce disruptions of the integration of

  11. Potentiating action of propofol at GABAA receptors of retinal bipolar cells

    DEFF Research Database (Denmark)

    Yue, Lan; Xie, An; Bruzik, Karol S


    Purpose. Propofol (2,6-diisopropyl phenol), a widely used systemic anesthetic, is known to potentiate GABA(A) receptor activity in a number of CNS neurons and to produce changes in electroretinographically recorded responses of the retina. However, little is known about propofol's effects...... on specific retinal neurons. The authors investigated the action of propofol on GABA-elicited membrane current responses of retinal bipolar cells, which have both GABA(A) and GABA(C) receptors. Methods. Single, enzymatically dissociated bipolar cells obtained from rat retina were treated with propofol...... + propofol) led to a progressive increase in peak response amplitude and, at higher propofol concentrations, additional changes that included a prolonged time course of response recovery. Pre-exposure of the cell to perfusing propofol typically enhanced the rate of development of potentiation produced...

  12. Ni-based amorphous alloy-coating for bipolar plate of PEM fuel cell by electrochemical plating

    International Nuclear Information System (INIS)

    Yamaura, S; Kim, S C; Inoue, A


    In this study, the Ni-Cr-P amorphous alloy-coated bipolar plates were produced by electro-plating on the Cu base plates with a flow field. The power generation tests of a single fuel cell with those Ni-Cr-P bipolar plates were conducted at 353 K. It was found that the single fuel cell with those Ni-Cr-P bipolar plates showed excellent I-V performance as well as that with the carbon graphite bipolar plates. It was also found that the single cell with those Ni-Cr-P bipolar plates showed better I-V performance than that with the Ni-P amorphous alloy-coated bipolar plates. Furthermore, the long-time operation test was conducted for 440 h with those Ni-Cr-P bipolar plates at the constant current density of 200 mA·cm −2 . As a result, it was found that the cell voltage gradually decreased at the beginning of the measurement before 300 h and then the voltage was kept constant after 300 h.

  13. Mef2d is essential for the maturation and integrity of retinal photoreceptor and bipolar cells. (United States)

    Omori, Yoshihiro; Kitamura, Tamiki; Yoshida, Satoyo; Kuwahara, Ryusuke; Chaya, Taro; Irie, Shoichi; Furukawa, Takahisa


    Mef2 transcription factors play a crucial role in cardiac and skeletal muscle differentiation. We found that Mef2d is highly expressed in the mouse retina and its loss causes photoreceptor degeneration similar to that observed in human retinitis pigmentosa patients. Electroretinograms (ERGs) were severely impaired in Mef2d-/- mice. Immunohistochemistry showed that photoreceptor and bipolar cell synapse protein levels severely decreased in the Mef2d-/- retina. Expression profiling by microarray analysis showed that Mef2d is required for the expression of various genes in photoreceptor and bipolar cells, including cone arrestin, Guca1b, Pde6h and Cacna1s, which encode outer segment and synapse proteins. We also observed that Mef2d synergistically activates the cone arrestin (Arr3) promoter with Crx, suggesting that functional cooperation between Mef2d and Crx is important for photoreceptor cell gene regulation. Taken together, our results show that Mef2d is essential for photoreceptor and bipolar cell gene expression, either independently or cooperatively with Crx. © 2015 Institution for Protein Research. Genes to Cells published by Wiley Publishing Asia Pty Ltd and the Molecular Biology Society of Japan.

  14. Development and degeneration of cone bipolar cells are independent of cone photoreceptors in a mouse model of retinitis pigmentosa.

    Directory of Open Access Journals (Sweden)

    Miao Chen

    Full Text Available Retinal photoreceptors die during retinal synaptogenesis in a portion of retinal degeneration. Whether cone bipolar cells establish regular retinal mosaics and mature morphologies, and resist degeneration are not completely understood. To explore these issues, we backcrossed a transgenic mouse expressing enhanced green fluorescent protein (EGFP in one subset of cone bipolar cells (type 7 into rd1 mice, a classic mouse model of retinal degeneration, to examine the development and survival of cone bipolar cells in a background of retinal degeneration. Our data revealed that both the development and degeneration of cone bipolar cells are independent of the normal activity of cone photoreceptors. We found that type 7 cone bipolar cells achieved a uniform tiling of the retinal surface and developed normal dendritic and axonal arbors without the influence of cone photoreceptor innervation. On the other hand, degeneration of type 7 cone bipolar cells, contrary to our belief of central-to-peripheral progression, was spatially uniform across the retina independent of the spatiotemporal pattern of cone degeneration. The results have important implications for the design of more effective therapies to restore vision in retinal degeneration.

  15. Cost and performance prospects for composite bipolar plates in fuel cells and redox flow batteries (United States)

    Minke, Christine; Hickmann, Thorsten; dos Santos, Antonio R.; Kunz, Ulrich; Turek, Thomas


    Carbon-polymer-composite bipolar plates (BPP) are suitable for fuel cell and flow battery applications. The advantages of both components are combined in a product with high electrical conductivity and good processability in convenient polymer forming processes. In a comprehensive techno-economic analysis of materials and production processes cost factors are quantified. For the first time a technical cost model for BPP is set up with tight integration of material characterization measurements.

  16. Surface roughness effect on the metallic bipolar plates of a proton exchange membrane fuel cell

    International Nuclear Information System (INIS)

    Lin, Chien-Hung


    Highlights: ► Various degrees of roughness are caused by the sandblasting method. ► An improper surface modification depletes the PEMFC performance severely. ► The AC impedance are used to assess the fuel gas transfer effect. ► The Warburg resistance form in the coarse flow channel surface. - Abstract: Proton exchange membrane fuel cells (PEMFCs) is a promising candidate as energy systems. However, the stability and lifetime of cells are still important issues. The effect of surface roughness on metallic bipolar plate is discussed in this paper. Various roughness on the bulk surface are obtained by the sandblasting method. The grain sizes of sand are selected as 50, 100 and 200 μm. The Ac impedance experiment results show that the bipolar plate roughness and carbon paper porosity are well matched when the surface roughness is within 1–2 μm. Superior condition decreases the contact resistance loss in the fuel cell. The high frequency resistance of the coarse surface was larger than that of the substrate by around 5 mΩ. Furthermore, a new arc was formed at the low frequency region. Hence, the unmatch roughness condition of the bipolar plate significantly increases the contact resistance and mass transfer resistance. This paper develops a sequential approach to study an optimum surface roughness by combining the whole performance (I–V) curve and AC impedance result. It benefits us to quantify the contact and mass transfer resistance exists in the PEMFC. The proposed surface treatment improves the surface effect and promotes the implement of potential metallic bipolar plate in near future

  17. Test Results of a Ten Cell Bipolar Nickel-hydrogen Battery (United States)

    Cataldo, R. L.


    A study was initiated to design and evaluate a new design concept for nickel-hydrogen cells. This concept involved constructing a battery in a bipolar stack with cells consisting of a one plate for each nickel and hydrogen electrode. Preliminary designs at the system level of this concept promised improvements in both volumetric and gravimetric energy densities, thermal management, life extension, costs, and peak power capability over more conventional designs. Test results were most encouraging. This preprototype battery, built with less than ideal components and hardware, exceeded expectations. A total of 2000 LEO cycles at 80 percent depth of discharge were accrued. A cycle life goal of 30,000 cycles appears achievable with minor design changes. These improvements include advanced technology nickel electrodes, insulated bipolar plates and specifically designed frames to minimize shunt currents. The discharge rate capability of this design exceeds 25C. At the 10C discharge rate, 80% of the battery capacity can be withdrawn in six minutes. This data shows that the bipolar design is well suited for those applications requiring high peak power pulses.

  18. Fabrication of carbon-polymer composite bipolar plates for polymer electrolyte membrane fuel cells by compression moulding

    International Nuclear Information System (INIS)

    Raza, M.A.; Ahmed, R.; Saleem, A.; Din, R.U.


    Fuel cells are considered as one of the most important technologies to address the future energy and environmental pollution problems. These are the most promising power sources for road transportation and portable devices. A fuel cell is an electrochemical device that converts chemical energy into electrical energy. A fuel cell stack consists of bipolar plates and membrane electrode assemblies (MEA). The bipolar plate is by weight, volume and cost one of the most significant components of a fuel cell stack. Major functions of bipolar plates are to separate oxidant and fuel gas, provide flow channels, conduct electricity and provide heat transfer. Bipolar plates can be made from various materials including graphite, metals, carbon / carbon and carbon/ polymer composites. Materials for carbon-polymer composites are relatively inexpensive, less corrosive, strong and channels can be formed by means of a moulding process. Carbon-polymer composites are of two type i.e; thermosetting and thermoplastic. For thermosetting composite a bulk molding compound (BMC) was prepared by adding graphite, vinyl ester resin, methyl ethyl ketone peroxide and cobalt naphthalate. The BMC was thoroughly mixed, poured into a die mould of a bipolar plate with channels and hot pressed at a specific temperature and pressure. A bipolar plate was formed according to the die mould. Design of the mould is also discussed. Conducting polymers were also added to BMC to increase the conductivity of bipolar plates. Particle size of the graphite has also a significant effect on the conductivity of the bipolar plates. Thermoplastic composites were also prepared using polypropylene and graphite.

  19. Collisional redistribution of the Na-D lines in a Ne, Xe filled vapour cell and depolarization in a flame

    International Nuclear Information System (INIS)

    Nieuwesteeg, K.J.B.M.


    1. Measurements of collisionally perturbed, 'complete' spectral profiles, i.e. core plus line wings of the Na-D lines, at the highest possible temperature in a fluorescence cell are reported. Both the shape of the profiles obtained in these experiments and the temperature dependence give information about the internuclear forces. Neon and xenon are chosen as perturbing atoms in order to extend and test potential shapes that have emerged from earlier beam experiments. 2. Possible ways are discussed of accurately calculating the cross sections of all elastic and inelastic processes in a Na- noble-gas system for any likely shape of the potentials involved. The main purpose of this discussion is to test these potentials by comparing the calculated cross sections with experimental data. Also a detailed comparison is made of the measured far-wing profile and the quasi-static profile calculated using these potentials. 3. In order to assess the validity of the approximations made in the theoretical model that was used for calculating the fluorescence-excitation profiles, the predictions of this model are compared with measurements of the polarization and the intensity ratio of the collision-induced Na-D fluorescence and Rayleigh scattering in an N 2 -diluted flame at 1 atm pressure. Using the Utrecht High-resolution Fourier Interferometer in the visible range, the Rayleigh peak and the collision-induced fluorescence were separated for the first time at laser detunings within the absorption line width. (Auth.)

  20. Development of a bipolar cell for lithium production

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, J.F.; Ebbinghaus, B.B.; Peterman, K.; Weinland, S. [Lawrence Livermore National Lab., CA (United States); McKenzie, P. [Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)


    The authors report development and bench-scale testing of an electrolytic process for reduction of LiOH to lithium metal through an amalgam intermediate. The amalgam is formed in an aqueous-electrolyte cell and stripped in a molten salt cell using a LiI-CsI eutectic at 225 C. Total energy efficiency is >70%. The process obviates high temperature materials problems, chlorine evolution and anhydrous feedstocks. While the principle is proven, sustained operation of the cell is now needed to obtain statistical data on reliability and maintainability.

  1. Efficient treatment of aniline containing wastewater in bipolar membrane microbial electrolysis cell-Fenton system. (United States)

    Li, Xiaohu; Jin, Xiangdan; Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng


    Aniline-containing wastewater can cause significant environmental problems and threaten the humans's life. However, rapid degradation of aniline with cost-efficient methods remains a challenge. In this work, a novel microbial electrolysis cell with bipolar membrane was integrated with Fenton reaction (MEC-Fenton) for efficient treatment of real wastewater containing a high concentration (4460 ± 52 mg L -1 ) of aniline. In this system, H 2 O 2 was in situ electro-synthesized from O 2 reduction on the graphite cathode and was simultaneously used as source of OH for the oxidation of aniline wastewater under an acidic condition maintained by the bipolar membrane. The aniline was effectively degraded following first-order kinetics at a rate constant of 0.0166 h -1 under an applied voltage of 0.5 V. Meanwhile, a total organic carbon (TOC) removal efficiency of 93.1 ± 1.2% was obtained, revealing efficient mineralization of aniline. The applicability of bipolar membrane MEC-Fenton system was successfully demonstrated with actual aniline wastewater. Moreover, energy balance showed that the system could be a promising technology for removal of biorefractory organic pollutants from wastewaters. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Konduktifitas Listrik Komposit Polimer Polipropilena/Karbon Untuk Aplikasi Pelat Bipolar Fuel Cell

    Directory of Open Access Journals (Sweden)

    Agus Pramono


    Full Text Available Proton exchange membrane fuel cell (PEMFC merupakan salah satu sumber energi alternatif yang saat ini sedang dikembangkan untuk mengatasi permasahan krisis energi dan lingkungan. Salah satu komponen yang mempunyai peran  signifikan dalam efisiensi biaya dan proses PEMFC adalah pelat bipolar. Untuk itu diperlukan pelat bipolar yang ringan, murah, dan mudah diproduksi secara masal. Dalam penelitian ini dikembangkan komposit pelat bipolar menggunakan matriks polipropilena (PP, penguat karbon hitam dan grafit elektroda dengan variasi komposisi wt% PP/grafit/CB sebesar 85:10:5; 75:20:5; 65:30:5;dan 55:40:5, sehingga mendapatkan sifat daya hantar listrik yang baik. Sifat-sifat dari komposit yang dihasilkan diuji dengan pengujian konduktivitas, Dari keempat formula, didapatkan bahwa sifat listrik yang paling baik terdapat pada formula empat dengan penambahan grafit sebesar 40 wt%. Formulasi empat memiliki konduktivitas listrik sebesar 2,523E-03 S/cm. sifat listrik juga belum optimal dikarenakan masih terdapatnya banyak rongga atau pori dalam komposit PP/grafit/CB yang disebabkan oleh udara yang terjebak selama proses penekanan.

  3. Nanosized TiN-SBR hybrid coating of stainless steel as bipolar plates for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Kumagai, Masanobu; Myung, Seung-Taek; Asaishi, Ryo; Sun, Yang-Kook; Yashiro, Hitoshi


    In attempt to improve interfacial electrical conductivity of stainless steel for bipolar plates of polymer electrolyte membrane fuel cells, TiN nanoparticles were electrophoretically deposited on the surface of stainless steel with elastic styrene butadiene rubber (SBR) particles. From transmission electron microscopic observation, it was found that the TiN nanoparticles (ca. 50 nm) surrounded the spherical SBR particles (ca. 300-600 nm), forming agglomerates. They were well adhered on the surface of the type 310S stainless steel. With help of elasticity of SBR, the agglomerates were well fitted into the interfacial gap between gas diffusion layer (GDL) and stainless steel bipolar plate, and the interfacial contact resistance (ICR), simultaneously, was successfully reduced. A single cell using the TiN nanoparticles-coated bipolar plates, consequently, showed comparable cell performance with the graphite employing cell at a current density of 0.5 A cm -2 (12.5 A). Inexpensive TiN nanoparticle-coated type 310S stainless steel bipolar plates would become a possible alternate for the expensive graphite bipolar plates as use in fuel cell applications

  4. Bipolar polaron pair recombination in polymer/fullerene solar cells

    DEFF Research Database (Denmark)

    Kupijai, Alexander J.; Behringer, Konstantin M.; Schaeble, Florian G.


    We present a study of the rate-limiting spin-dependent charge-transfer processes in different polymer/fullerene bulk-heterojunction solar cells at 10 K. Observing central spin-locking signals in pulsed electrically detected magnetic resonance and an inversion of Rabi oscillations in multifrequency...

  5. Neuronal Depolarization Drives Increased Dopamine Synaptic Vesicle Loading via VGLUT. (United States)

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


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

  6. Assessing the utility of bipolar membranes for use in photoelectrochemical water-splitting cells. (United States)

    Vargas-Barbosa, Nella M; Geise, Geoffrey M; Hickner, Michael A; Mallouk, Thomas E


    Membranes are important in water-splitting solar cells because they prevent crossover of hydrogen and oxygen. Here, bipolar membranes (BPMs) were tested as separators in water electrolysis cells. Steady-state membrane and solution resistances, electrode overpotentials, and pH gradients were measured at current densities relevant to solar photoelectrolysis. Under forward bias conditions, electrodialysis of phosphate buffer ions creates a pH gradient across a BPM. Under reverse bias, the BPM can maintain a constant buffer pH on both sides of the cell, but a large membrane potential develops. Thus, the BPM does not present a viable solution for electrolysis in buffered electrolytes. However, the membrane potential is minimized when the anode and cathode compartments of the cell contain strongly basic and acidic electrolytes, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Evaluation of materials for bipolar plates in simulated PEM fuel-cell cathodic environments

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, S.V.; Belmonte, M.R.; Moron, L.E.; Torres, J.; Orozco, G. [Centro de Investigacion y Desarrollo Technologico en Electroquimica S.C. Parcque Sanfandila, Queretaro (Mexico); Perez-Quiroz, J.T. [Mexican Transport Inst., Queretaro (Mexico); Cortes, M. A. [Mexican Petroleum Inst., Mexico City (Mexico)


    The bipolar plates in proton exchange membrane fuel cells (PEMFC) are exposed to an oxidizing environment on the cathodic side, and therefore are susceptible to corrosion. Corrosion resistant materials are needed for the bipolar plates in order to improve the lifespan of fuel cells. This article described a study in which a molybdenum (Mo) coating was deposited over austenitic stainless steel 316 and carbon steel as substrates in order to evaluate the resulting surfaces with respect to their corrosion resistance in simulated anodic and cathodic PEMFC environments. The molybdenum oxide films were characterized by scanning electron microscopy (SEM) and Raman spectroscopy. The article presented the experiment and discussed the results of the corrosion behaviour of coated stainless steel. In general, the electrochemical characterization of bare materials and coated steel consisted of slow potentiodynamic polarization curves followed by a constant potential polarization test. The test medium was 0.5M sulfuric acid with additional introduction of oxygen to simulate the cathodic environment. All tests were performed at ambient temperature and at 50 degrees Celsius. The potentiostat used was a Gamry instrument. It was concluded that it is possible to deposit Mo-oxides on steel without using another alloying metal. The preferred substrate for corrosion prevention was found to be an alloy with high chromium content. 24 refs., 4 figs.

  8. Theoretical design strategies of bipolar membrane fuel cell with enhanced self-humidification behavior (United States)

    Li, Qiushi; Gong, Jian; Peng, Sikan; Lu, Shanfu; Sui, Pang-Chieh; Djilali, Ned; Xiang, Yan


    The bipolar membrane fuel cells (BPMFCs), which have a unique acid-alkaline jointed membrane electrode assembly (MEA) structure, have demonstrated their great potential for self-humidification during operation. Although the self-humidification ability of such bipolar membranes (BPMs) has recently been validated by a one-dimensional BPM model, the transport mechanism and the formation of self-humidification in the MEAs are not well understood. In the present study, a two-dimensional cross-channel MEA model is developed to elucidate the mechanisms and enhancement of water transport on self-humidification with comprehensive consideration of the three electrochemical reaction zones. The water-formation interface model has been successfully investigated by theoretical and experimental interface reaction kinetics, streamlines of water flux present the formation process and mechanism of self-humidification. A critical current (voltage) value, beyond which self-humidification is initiated, is identified. It is also found that such critical current (voltage) can be adjusted by changing the membrane thickness and the water uptake property of the ionomer. It is concluded that fabricating BPMs with proper membrane thickness and water uptake property are effective strategies to enhance the water management and cell performance in BPMFCs.

  9. Glia and immune cell signaling in bipolar disorder: insights from neuropharmacology and molecular imaging to clinical application. (United States)

    Watkins, C C; Sawa, A; Pomper, M G


    Bipolar disorder (BD) is a debilitating mental illness characterized by severe fluctuations in mood, sleep, energy and executive functioning. Pharmacological studies of selective serotonin reuptake inhibitors and the monoamine system have helped us to clinically understand bipolar depression. Mood stabilizers such as lithium and valproic acid, the first-line treatments for bipolar mania and depression, inhibit glycogen synthase kinase-3 beta (GSK-3β) and regulate the Wnt pathway. Recent investigations suggest that microglia, the resident immune cells of the brain, provide a physiological link between the serotonin system and the GSK-3β/Wnt pathway through neuroinflammation. We review the pharmacological, translational and brain imaging studies that support a role for microglia in regulating neurotransmitter synthesis and immune cell activation. These investigations provide a model for microglia involvement in the pathophysiology and phenotype of BD that may translate into improved therapies.

  10. Requirements and testing methods for surfaces of metallic bipolar plates for low-temperature PEM fuel cells (United States)

    Jendras, P.; Lötsch, K.; von Unwerth, T.


    To reduce emissions and to substitute combustion engines automotive manufacturers, legislature and first users aspire hydrogen fuel cell vehicles. Up to now the focus of research was set on ensuring functionality and increasing durability of fuel cell components. Therefore, expensive materials were used. Contemporary research and development try to substitute these substances by more cost-effective material combinations. The bipolar plate is a key component with the greatest influence on volume and mass of a fuel cell stack and they have to meet complex requirements. They support bending sensitive components of stack, spread reactants over active cell area and form the electrical contact to another cell. Furthermore, bipolar plates dissipate heat of reaction and separate one cell gastight from the other. Consequently, they need a low interfacial contact resistance (ICR) to the gas diffusion layer, high flexural strength, good thermal conductivity and a high durability. To reduce costs stainless steel is a favoured material for bipolar plates in automotive applications. Steel is characterized by good electrical and thermal conductivity but the acid environment requires a high chemical durability against corrosion as well. On the one hand formation of a passivating oxide layer increasing ICR should be inhibited. On the other hand pitting corrosion leading to increased permeation rate may not occur. Therefore, a suitable substrate lamination combination is wanted. In this study material testing methods for bipolar plates are considered.

  11. Multilayer graphene for long-term corrosion protection of stainless steel bipolar plates for polymer electrolyte membrane fuel cell

    DEFF Research Database (Denmark)

    Stoot, Adam Carsten; Camilli, Luca; Spiegelhauer, Susie Ann


    Abstract Motivated by similar investigations recently published (Pu et al., 2015), we report a comparative corrosion study of three sets of samples relevant as bipolar plates for polymer electrolyte fuel cells: stainless steel, stainless steel with a nickel seed layer (Ni/SS) and stainless steel...

  12. The TRPM1 Channel Is Required for Development of the Rod ON Bipolar Cell-AII Amacrine Cell Pathway in the Retinal Circuit. (United States)

    Kozuka, Takashi; Chaya, Taro; Tamalu, Fuminobu; Shimada, Mariko; Fujimaki-Aoba, Kayo; Kuwahara, Ryusuke; Watanabe, Shu-Ichi; Furukawa, Takahisa


    Neurotransmission plays an essential role in neural circuit formation in the central nervous system (CNS). Although neurotransmission has been recently clarified as a key modulator of retinal circuit development, the roles of individual synaptic transmissions are not yet fully understood. In the current study, we investigated the role of neurotransmission from photoreceptor cells to ON bipolar cells in development using mutant mouse lines of both sexes in which this transmission is abrogated. We found that deletion of the ON bipolar cation channel TRPM1 results in the abnormal contraction of rod bipolar terminals and a decreased number of their synaptic connections with amacrine cells. In contrast, these histological alterations were not caused by a disruption of total glutamate transmission due to loss of the ON bipolar glutamate receptor mGluR6 or the photoreceptor glutamate transporter VGluT1. In addition, TRPM1 deficiency led to the reduction of total dendritic length, branch numbers, and cell body size in AII amacrine cells. Activated Goα, known to close the TRPM1 channel, interacted with TRPM1 and induced the contraction of rod bipolar terminals. Furthermore, overexpression of Channelrhodopsin-2 partially rescued rod bipolar cell development in the TRPM1 -/- retina, whereas the rescue effect by a constitutively closed form of TRPM1 was lower than that by the native form. Our results suggest that TRPM1 channel opening is essential for rod bipolar pathway establishment in development. SIGNIFICANCE STATEMENT Neurotransmission has been recognized recently as a key modulator of retinal circuit development in the CNS. However, the roles of individual synaptic transmissions are not yet fully understood. In the current study, we focused on neurotransmission between rod photoreceptor cells and rod bipolar cells in the retina. We used genetically modified mouse models which abrogate each step of neurotransmission: presynaptic glutamate release, postsynaptic glutamate

  13. Glucose stimulates neurotensin secretion from the rat small intestine by mechanisms involving SGLT1 and GLUT2 leading to cell depolarization and calcium influx

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Bechmann, Louise Ellegaard; Hartmann, Bolette


    of secretion. Luminal glucose (20% wt/vol) stimulated secretion but vascular glucose (5, 10, or 15 mmol/l) was without effect. The underlying mechanisms depend on membrane depolarization and calcium influx, since the voltage-gated calcium channel inhibitor nifedipine and the KATP channel opener diazoxide......, suggesting that glucose stimulates secretion by initial uptake by this transporter. However, secretion was also sensitive to GLUT2 inhibition (by phloretin) and blockage of oxidative phosphorylation (2-4-dinitrophenol). Direct KATP channel closure by sulfonylureas stimulated secretion. Therefore, glucose...

  14. Bipolar Plates for PEM Systems


    Lædre, Sigrid


    Summary of thesis: The Bipolar Plate (BPP) is an important component in both Proton Exchange Membrane Fuel Cells (PEMFCs) and Proton Exchange Membrane Water Electrolyzers (PEMWEs). Bipolar plate material and processing constitutes for a large fraction of the cost and weight of a PEM cell stack. The main tasks for the bipolar plates in both systems are to separate single cell in a stack, conduct current between single cells and remove heat from active areas. In addition, the BPPs distribu...

  15. High-pass filtering of input signals by the Ih current in a non-spiking neuron, the retinal rod bipolar cell.

    Directory of Open Access Journals (Sweden)

    Lorenzo Cangiano

    Full Text Available Hyperpolarization-activated cyclic nucleotide-sensitive (HCN channels mediate the I(f current in heart and I(h throughout the nervous system. In spiking neurons I(h participates primarily in different forms of rhythmic activity. Little is known, however, about its role in neurons operating with graded potentials as in the retina, where all four channel isoforms are expressed. Intriguing evidence for an involvement of I(h in early visual processing are the side effects reported, in dim light or darkness, by cardiac patients treated with HCN inhibitors. Moreover, electroretinographic recordings indicate that these drugs affect temporal processing in the outer retina. Here we analyzed the functional role of HCN channels in rod bipolar cells (RBCs of the mouse. Perforated-patch recordings in the dark-adapted slice found that RBCs exhibit I(h, and that this is sensitive to the specific blocker ZD7288. RBC input impedance, explored by sinusoidal frequency-modulated current stimuli (0.1-30 Hz, displays band-pass behavior in the range of I(h activation. Theoretical modeling and pharmacological blockade demonstrate that high-pass filtering of input signals by I(h, in combination with low-pass filtering by passive properties, fully accounts for this frequency-tuning. Correcting for the depolarization introduced by shunting through the pipette-membrane seal, leads to predict that in darkness I(h is tonically active in RBCs and quickens their responses to dim light stimuli. Immunohistochemistry targeting candidate subunit isoforms HCN1-2, in combination with markers of RBCs (PKC and rod-RBC synaptic contacts (bassoon, mGluR6, Kv1.3, suggests that RBCs express HCN2 on the tip of their dendrites. The functional properties conferred by I(h onto RBCs may contribute to shape the retina's light response and explain the visual side effects of HCN inhibitors.

  16. Iron-based alloy and nitridation treatment for PEM fuel cell bipolar plates (United States)

    Brady, Michael P [Oak Ridge, TN; Yang, Bing [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN


    A corrosion resistant electrically conductive component that can be used as a bipolar plate in a PEM fuel cell application is composed of an alloy substrate which has 10-30 wt. % Cr, 0.5 to 7 wt. % V, and base metal being Fe, and a continuous surface layer of chromium nitride and vanadium nitride essentially free of base metal. A oxide layer of chromium vanadium oxide can be disposed between the alloy substrate and the continuous surface nitride layer. A method to prepare the corrosion resistant electrically conductive component involves a two-step nitridization sequence by exposing the alloy to a oxygen containing gas at an elevated temperature, and subsequently exposing the alloy to an oxygen free nitrogen containing gas at an elevated temperature to yield a component where a continuous chromium nitride layer free of iron has formed at the surface.

  17. Flow field bipolar plates in a proton exchange membrane fuel cell: Analysis & modeling

    International Nuclear Information System (INIS)

    Kahraman, Huseyin; Orhan, Mehmet F.


    Highlights: • Covers a comprehensive review of available flow field channel configurations. • Examines the main design considerations and limitations for a flow field network. • Explores the common materials and material properties used for flow field plates. • Presents a case study of step-by-step modeling for an optimum flow field design. - Abstract: This study investigates flow fields and flow field plates (bipolar plates) in proton exchange membrane fuel cells. In this regard, the main design considerations and limitations for a flow field network have been examined, along with a comprehensive review of currently available flow field channel configurations. Also, the common materials and material properties used for flow field plates have been explored. Furthermore, a case study of step-by-step modeling for an optimum flow field design has been presented in-details. Finally, a parametric study has been conducted with respect to many design and performance parameters in a flow field plate.

  18. Bipolar plate materials in molten carbonate fuel cells. Final CRADA report.

    Energy Technology Data Exchange (ETDEWEB)

    Krumpelt, M.


    Advantages of implementation of power plants based on electrochemical reactions are successfully demonstrated in the USA and Japan. One of the msot promising types of fuel cells (FC) is a type of high temperature fuel cells. At present, thanks to the efforts of the leading countries that develop fuel cell technologies power plants on the basis of molten carbonate fuel cells (MCFC) and solid oxide fuel cells (SOFC) are really close to commercialization. One of the problems that are to be solved for practical implementation of MCFC and SOFC is a problem of corrosion of metal components of stacks that are assembled of a number of fuel cells. One of the major components of MCFC and SOFC stacks is a bipolar separator plate (BSP) that performs several functions - it is separation of reactant gas flows sealing of the joints between fuel cells, and current collection from the surface of electrodes. The goal of Task 1 of the project is to develop new cost-effective nickel coatings for the Russian 20X23H18 steel for an MCFC bipolar separator plate using technological processes usually implemented to apply corrosion stable coatings onto the metal parts for products in the defense. There was planned the research on production of nickel coatings using different methods, first of all the galvanic one and the explosion cladding one. As a result of the works, 0.4 x 712 x 1296 mm plates coated with nickel on one side were to be made and passed to ANL. A line of 4 galvanic baths 600 liters was to be built for the galvanic coating applications. The goal of Task 2 of the project is the development of a new material of an MCFC bipolar separator plate with an upgraded corrosion stability, and development of a technology to produce cold roll sheets of this material the sizes of which will be 0.8 x 712x 1296 mm. As a result of these works, a pilot batch of the rolled material in sheets 0.8 x 712 x 1296 mm in size is to be made (in accordance with the norms and standards of the Russian

  19. Electroplating of Ni-Mo Coating on Stainless Steel for Application in Proton Exchange Membrane Fuel Cell Bipolar Plate

    Directory of Open Access Journals (Sweden)

    H. Rashtchi


    Full Text Available Stainless steel bipolar plates are preferred choice for use in Proton Exchange Membrane Fuel Cells (PEMFCs. However, regarding the working temperature of 80 °C and corrosive and acidic environment of PEMFC, it is necessary to apply conductive protective coatings resistant to corrosion on metallic bipolar plate surfaces to enhance its chemical stability and performance. In the present study, by applying Ni-Mo and Ni-Mo-P alloy coatings via electroplating technique, corrosion resistance was improved, oxid layers formation on substrates which led to increased electrical conductivity of the surface was reduced and consequently bipolar plates fuction was enhanced. Evaluation tests included microstructural and phase characterizations for evaluating coating components; cyclic voltammetry test for electrochemical behavior investigations; wettability test for measuring hydrophobicity characterizations of the coatings surfaces; interfacial contact resistance measurements of the coatings for evaluating the composition of applied coatings; and polarization tests of fuel cells for evaluating bipolar plates function in working conditions. Finally, the results showed that the above-mentioned coatings considerably decreased the corrosion and electrical resistance of the stainless steel.

  20. Characterization of Thermal and Mechanical Properties of Polypropylene-Based Composites for Fuel Cell Bipolar Plates and Development of Educational Tools in Hydrogen and Fuel Cell Technologies (United States)

    Lopez Gaxiola, Daniel


    In this project we developed conductive thermoplastic resins by adding varying amounts of three different carbon fillers: carbon black (CB), synthetic graphite (SG) and multi-walled carbon nanotubes (CNT) to a polypropylene matrix for application as fuel cell bipolar plates. This component of fuel cells provides mechanical support to the stack,…

  1. Polyalthia longifolia Methanolic Leaf Extracts (PLME) induce apoptosis, cell cycle arrest and mitochondrial potential depolarization by possibly modulating the redox status in hela cells. (United States)

    Vijayarathna, Soundararajan; Oon, Chern Ein; Chen, Yeng; Kanwar, Jagat R; Sasidharan, Sreenivasan


    Medicinal plants have been accepted as a gold mine, with respect to the diversity of their phytochemicals. Many medicinal plants extracts are potential anticancer agents. Polyalthia longifolia var. angustifolia Thw. (Annonaceae) is one of the most significant native medicinal plants and is found throughout Malaysia. Hence, the present study was intended to assess the anticancer properties of P. longifolia leaf methanolic extract (PLME) and its underlying mechanisms. The Annexin V/PI flow cytometry analysis showed that PLME induces apoptosis in HeLa cells in dose-dependent manner whereas the PI flow cytometric analysis for cell cycle demonstrated the accumulation of cells at sub G0/G1, G0/G1 and G2/M phases. Investigation with JC-1 flow cytometry analysis indicated increase in mitochondria membrane potential depolarisation corresponding to increase in PLME concentrations. PLME was also shown to influence intracellular reactive oxygen species (ROS) by exerting anti-oxidant (half IC 50 ) and pro-oxidant (IC 50 and double IC 50 ) affect against HeLa cells. PLME treatment also displayed DNA damage in HeLa cells in concentration depended fashion. The proteomic profiling array exposed the expression of pro-apoptotic and anti-apoptotic proteins upon PLME treatment at IC 50 concentration in HeLa cells. Pro-apoptotic proteins; BAX, BAD, cytochrome c, caspase-3, p21, p27 and p53 were found to be significantly up-regulated while anti-apoptotic proteins; BCL-2 and BCL-w were found to be significantly down-regulated. This investigation postulated the role of p53 into mediating apoptosis, cell cycle arrest and mitochondrial potential depolarisation by modulating the redox status of HeLa cells. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. LW6, a hypoxia-inducible factor 1 inhibitor, selectively induces apoptosis in hypoxic cells through depolarization of mitochondria in A549 human lung cancer cells. (United States)

    Sato, Mariko; Hirose, Katsumi; Kashiwakura, Ikuo; Aoki, Masahiko; Kawaguchi, Hideo; Hatayama, Yoshiomi; Akimoto, Hiroyoshi; Narita, Yuichiro; Takai, Yoshihiro


    Hypoxia‑inducible factor 1 (HIF‑1) activates the transcription of genes that act upon the adaptation of cancer cells to hypoxia. LW6, an HIF‑1 inhibitor, was hypothesized to improve resistance to cancer therapy in hypoxic tumors by inhibiting the accumulation of HIF‑1α. A clear anti‑tumor effect under low oxygen conditions would indicate that LW6 may be an improved treatment strategy for cancer in hypoxia. In the present study, the HIF‑1 inhibition potential of LW6 on the growth and apoptosis of A549 lung cancer cells in association with oxygen availability was evaluated. LW6 was observed to inhibit the expression of HIF‑1α induced by hypoxia in A549 cells at 20 mM, independently of the von Hippel‑Lindau protein. In addition, at this concentration, LW6 induced hypoxia‑selective apoptosis together with a reduction in the mitochondrial membrane potential. The intracellular reactive oxygen species levels increased in LW6‑treated hypoxic A549 cells and LW6 induced a hypoxia‑selective increase of mitochondrial O2•‑. In conclusion, LW6 inhibited the growth of hypoxic A549 cells by affecting the mitochondria. The inhibition of the mitochondrial respiratory chain is suggested as a potentially effective strategy to target apoptosis in cancer cells.

  3. Localization of Rod Bipolar Cells in the Mammalian Retina Using an Antibody Against the α1c L-type Ca2+ Channel

    International Nuclear Information System (INIS)

    Huh, Yu-Jin; Choi, Jae-Sik; Jeon, Chang-Jin


    Bipolar cells transmit stimuli via graded changes in membrane potential and neurotransmitter release is modulated by Ca 2+ influx through L-type Ca 2+ channels. The purpose of this study was to determine whether the α 1 c subunit of L-type voltage-gated Ca 2+ channel (α 1 c L-type Ca 2+ channel) colocalizes with protein kinase C alpha (PKC-α), which labels rod bipolar cells. Retinal whole mounts and vertical sections from mouse, hamster, rabbit, and dog were immunolabeled with antibodies against PKC-α and α 1 c L-type Ca 2+ channel, using fluorescein isothiocyanate (FITC) and Cy5 as visualizing agents. PKC-α-immunoreactive cells were morphologically identical to rod bipolar cells as previously reported. Their cell bodies were located within the inner nuclear layer, dendritic processes branched into the outer plexiform layer, and axons extended into the inner plexiform layer. Immunostaining showed that α 1 c L-type Ca 2+ channel colocalized with PKC-α in rod bipolar cells. The identical expression of PKC-α and α 1 c L-type Ca 2+ channel indicates that the α 1 c L-type Ca 2+ channel has a specific role in rod bipolar cells, and the antibody against the α 1 c L-type Ca 2+ channel may be a useful marker for studying the distribution of rod bipolar cells in mouse, hamster, rabbit, and dog retinas

  4. Cyanidin-3-glucoside inhibits glutamate-induced Zn2+ signaling and neuronal cell death in cultured rat hippocampal neurons by inhibiting Ca2+-induced mitochondrial depolarization and formation of reactive oxygen species. (United States)

    Yang, Ji Seon; Perveen, Shazia; Ha, Tae Joung; Kim, Seong Yun; Yoon, Shin Hee


    Cyanidin-3-glucoside (C3G), a member of the anthocyanin family, is a potent natural antioxidant. However, effects of C3G on glutamate-induced [Zn(2+)]i increase and neuronal cell death remain unknown. We studied the effects of C3G on glutamate-induced [Zn(2+)]i increase and cell death in cultured rat hippocampal neurons from embryonic day 17 maternal Sprague-Dawley rats using digital imaging methods for Zn(2+), Ca(2+), reactive oxygen species (ROS), mitochondrial membrane potential and a MTT assay for cell survival. Treatment with glutamate (100 µM) for 7 min induces reproducible [Zn(2+)]i increase at 35 min interval in cultured rat hippocampal neurons. The intracellular Zn(2+)-chelator TPEN markedly blocked glutamate-induced [Zn(2+)]i increase, but the extracellular Zn(2+) chelator CaEDTA did not affect glutamate-induced [Zn(2+)]i increase. C3G inhibited the glutamate-induced [Zn(2+)]i response in a concentration-dependent manner (IC50 of 14.1 ± 1.1 µg/ml). C3G also significantly inhibited glutamate-induced [Ca(2+)]i increase. Two antioxidants such as Trolox and DTT significantly inhibited the glutamate-induced [Zn(2+)]i response, but they did not affect the [Ca(2+)]i responses. C3G blocked glutamate-induced formation of ROS. Trolox and DTT also inhibited the formation of ROS. C3G significantly inhibited glutamate-induced mitochondrial depolarization. However, TPEN, Trolox and DTT did not affect the mitochondrial depolarization. C3G, Trolox and DTT attenuated glutamate-induced neuronal cell death in cultured rat hippocampal neurons, respectively. Taken together, all these results suggest that cyanidin-3-glucoside inhibits glutamate-induced [Zn(2+)]i increase through a release of Zn(2+) from intracellular sources in cultured rat hippocampal neurons by inhibiting Ca(2+)-induced mitochondrial depolarization and formation of ROS, which is involved in neuroprotection against glutamate-induced cell death. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Bipolar cell gap junctions serve major signaling pathways in the human retina. (United States)

    Kántor, Orsolya; Varga, Alexandra; Nitschke, Roland; Naumann, Angela; Énzsöly, Anna; Lukáts, Ákos; Szabó, Arnold; Németh, János; Völgyi, Béla


    Connexin36 (Cx36) constituent gap junctions (GJ) throughout the brain connect neurons into functional syncytia. In the retina they underlie the transmission, averaging and correlation of signals prior conveying visual information to the brain. This is the first study that describes retinal bipolar cell (BC) GJs in the human inner retina, whose function is enigmatic even in the examined animal models. Furthermore, a number of unique features (e.g. fovea, trichromacy, midget system) necessitate a reexamination of the animal model results in the human retina. Well-preserved postmortem human samples of this study are allowed to identify Cx36 expressing BCs neurochemically. Results reveal that both rod and cone pathway interneurons display strong Cx36 expression. Rod BC inputs to AII amacrine cells (AC) appear in juxtaposition to AII GJs, thus suggesting a strategic AII cell targeting by rod BCs. Cone BCs serving midget, parasol or koniocellular signaling pathways display a wealth of Cx36 expression to form homologously coupled arrays. In addition, they also establish heterologous GJ contacts to serve an exchange of information between parallel signaling streams. Interestingly, a prominent Cx36 expression was exhibited by midget system BCs that appear to maintain intimate contacts with bistratified BCs serving other pathways. These findings suggest that BC GJs in parallel signaling streams serve both an intra- and inter-pathway exchange of signals in the human retina.

  6. Porous Composite for Bipolar Plate in Low Emission Hydrogen Fuel Cells

    Directory of Open Access Journals (Sweden)

    Renata Katarzyna Włodarczyk


    Full Text Available The paper presents the results of graphite-stainless steel composites for the bipolar plates in low-temperature fuel cells. The sinters were performed by powder metallurgy technology. The influenceof technological parameters, especially molding pressure were examined. Following the requirements formulated by the DOE concerning the parameters of the materials, it indicated by the value of the parameters. The density, flowabilit, particle size of graphite and stainless steel powders have been evaluated. Composites have been tested by microstructure and phase analysis, properties of strength, functional properties: wettability, porosity, roughness. The special attention was paid to the analysis of corrosion resistance obtained sinters and influenceof technological parameters on the corrosion. Corrosion tests were carried out under conditions simulating the environment of the fuel cell under anode and cathode conditions. The effectof pH solution during working of the cell on corrosion resistance of composites have been evaluated. Contact resistance depends on roughness of sinters. Low ICR determined high contact area GDL-BP and high electrical conductivity on the contact surface. The ICR in anode conditions after corrosion tests are not change significantly; composite materials can be used for materials for B in terms of H 2 .

  7. Bipolar Disorder (United States)

    Bipolar disorder is a serious mental illness. People who have it go through unusual mood changes. They go ... The down feeling is depression. The causes of bipolar disorder aren't always clear. It runs in families. ...

  8. Ag-polytetrafluoroethylene composite coating on stainless steel as bipolar plate of proton exchange membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yu. [Laboratory of Fuel Cells, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Hou, Ming; Shao, Zhigang; Yi, Baolian [Laboratory of Fuel Cells, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Xu, Hongfeng; Hou, Zhongjun; Ming, Pingwen [Sunrise Power Co., Ltd., Dalian 116025 (China)


    Forming a coating on metals by surface treatment is a good way to get high performance bipolar plate of proton exchange membrane fuel cell (PEMFC). In our research, Ag-polytetrafluoroethylene (PTFE) composite film was electrodeposited with silver-gilt solution of nicotinic acid by a bi-pulse electroplating power supply on 316 L stainless steel bipolar plate of PEMFC. Surface topography, contact angle, interfacial conductivity and corrosion resistance of the bipolar plate samples were investigated. Results showed that the defects on the Ag-PTFE composite coating are greatly reduced compared with those on the pure Ag coating fabricated under the same condition; and the contact angle of the Ag-PTFE composite coating with water is 114 , which is much bigger than that of the pure Ag coating (73 ). In addition, the interfacial contact resistance of the composite coating stays as low as the pure Ag coating; and the bipolar plate sample with composite coating shows a close corrosion resistance to the pure Ag coating sample in potentiodynamic and potentiostatic tests. Coated 316 L stainless steel plate with Ag-PTFE composite coating exhibits well hydrophobic characteristic, less defects, high interfacial conductivity and good corrosion resistance, which shows a great potential of the application in PEMFC. (author)

  9. Serum TRPM1 autoantibodies from melanoma associated retinopathy patients enter retinal on-bipolar cells and attenuate the electroretinogram in mice.

    Directory of Open Access Journals (Sweden)

    Wei-Hong Xiong

    Full Text Available Melanoma-associated retinopathy (MAR is a paraneoplastic syndrome associated with cutaneous malignant melanoma and the presence of autoantibodies that label neurons in the inner retina. The visual symptoms and electroretinogram (ERG phenotype characteristic of MAR resemble the congenital visual disease caused by mutations in TRPM1, a cation channel expressed by both melanocytes and retinal bipolar cells. Four serum samples from MAR patients were identified as TRPM1 immunoreactive by 1. Labeling of ON-bipolar cells in TRPM1+/+ but not TRPM1-/- mouse retina, 2. Labeling of TRPM1-transfected CHO cells; and 3. Attenuation of the ERG b-wave following intravitreal injection of TRPM1-positive MAR IgG into wild-type mouse eyes, and the appearance of the IgG in the retinal bipolar cells at the conclusion of the experiment. Furthermore, the epitope targeted by the MAR autoantibodies was localized within the amino-terminal cytoplasmic domain of TRPM1. Incubation of live retinal neurons with TRPM1-positive MAR serum resulted in the selective accumulation of IgG in ON-bipolar cells from TRPM1+/+ mice, but not TRPM1-/- mice, suggesting that the visual deficits in MAR are caused by the uptake of TRPM1 autoantibodies into ON-bipolar cells, where they bind to an intracellular epitope of the channel and reduce the ON-bipolar cell response to light.

  10. PEM fuel cells with injection moulded bipolar plates of highly filled graphite compounds; PEM-Brennstoffzellen mit spritzgegossenen Bipolarplatten aus hochgefuelltem Graphit-Compound

    Energy Technology Data Exchange (ETDEWEB)

    Kreuz, Can


    This work concerns with the injection moulding of highly filled graphite compounds to bipolar plates for PEM fuel cells in a power output range between 100 - 500 Watts. A particular focus is laid on the combination of the three multidisciplinary scopes like material development, production technology and component development / design. The results of the work are specified by the process-oriented characterisation of the developed and manufactured bipolar plates as well as their application in a functioning fuel cell. (orig.)

  11. Influences of bipolar plate channel blockages on PEM fuel cell performances

    International Nuclear Information System (INIS)

    Heidary, Hadi; Kermani, Mohammad J.; Dabir, Bahram


    Highlights: • Effect of partial- or full-blockage of PEMFC flow channels is numerically studied. • The anode blockage does not show any positive effects on cell performance. • Full blockages, despite higher pressure drop, better enhance net electrical power. • Additions of blocks more than five do not improve the cell performance. • Full blockage of cathode channels with five blocks enhances the net power by 30%. - Abstract: In this paper, the effect of partial- or full-block placement along the flow channels of PEM fuel cells is numerically studied. Blockage in the channel of flow-field diverts the flow into the gas diffusion layer (GDL) and enhances the mass transport from the channel core part to the catalyst layer, which in turn improves the cell performance. By partial blockage, only a part of the channel flow is shut off. While in full blockage, in which the flow channel cross sections are fully blocked, the only avenue left for the continuation of the gas is to travel over the blocks via the porous zone (GDL). In this study, a 3D numerical model consisting of a 9-layer PEM fuel cell is performed. A wide spectrum of numerical studies is performed to study the influences of the number of blocks, blocks height, and anode/cathode-side flow channel blockage. The results show that the case of full blockage enhances the net electrical power more than that of the partial blockage, in spite of higher pressure drop. Performed studies show that full blockage of the cathode-side flow channels with five blocks along the 5 cm channel enhances the net power by 30%. The present work provides helpful guidelines to bipolar plate manufacturers.

  12. Depolarization on Earth-space paths (United States)


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

  13. Modulation of electromagnetic fields by a depolarizer of random polarizer array

    DEFF Research Database (Denmark)

    Ma, Ning; Hanson, Steen Grüner; Wang, Wei


    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 ran......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...

  14. Bipolar Electrode Array Embedded in a Polymer Light-Emitting Electrochemical Cell. (United States)

    Gao, Jun; Chen, Shulun; AlTal, Faleh; Hu, Shiyu; Bouffier, Laurent; Wantz, Guillaume


    A linear array of aluminum discs is deposited between the driving electrodes of an extremely large planar polymer light-emitting electrochemical cell (PLEC). The planar PLEC is then operated at a constant bias voltage of 100 V. This promotes in situ electrochemical doping of the luminescent polymer from both the driving electrodes and the aluminum discs. These aluminum discs function as discrete bipolar electrodes (BPEs) that can drive redox reactions at their extremities. Time-lapse fluorescence imaging reveals that p- and n-doping that originated from neighboring BPEs can interact to form multiple light-emitting p-n junctions in series. This provides direct evidence of the working principle of bulk homojunction PLECs. The propagation of p-doping is faster from the BPEs than from the positive driving electrode due to electric field enhancement at the extremities of BPEs. The effect of field enhancement and the fact that the doping fronts only need to travel the distance between the neighboring BPEs to form a light-emitting junction greatly reduce the response time for electroluminescence in the region containing the BPE array. The near simultaneous formation of multiple light-emitting p-n junctions in series causes a measurable increase in cell current. This indicates that the region containing a BPE is much more conductive than the rest of the planar cell despite the latter's greater width. The p- and n-doping originating from the BPEs is initially highly confined. Significant expansion and divergence of doping occurred when the region containing the BPE array became more conductive. The shape and direction of expanded doping strongly suggest that the multiple light-emitting p-n junctions, formed between and connected by the array of metal BPEs, have functioned as a single rod-shaped BPE. This represents a new type of BPE that is formed in situ and as a combination of metal, doped polymers, and forward-biased p-n junctions connected in series.

  15. Distinct lithium-induced gene expression effects in lymphoblastoid cell lines from patients with bipolar disorder. (United States)

    Fries, Gabriel R; Colpo, Gabriela D; Monroy-Jaramillo, Nancy; Zhao, Junfei; Zhao, Zhongming; Arnold, Jodi G; Bowden, Charles L; Walss-Bass, Consuelo


    Lithium is the most commonly prescribed medication for the treatment of bipolar disorder (BD), yet the mechanisms underlying its beneficial effects are still unclear. We aimed to compare the effects of lithium treatment in lymphoblastoid cell lines (LCLs) from BD patients and controls. LCLs were generated from sixty-two BD patients (based on DSM-IV) and seventeen healthy controls matched for age, sex, and ethnicity. Patients were recruited from outpatient clinics from February 2012 to October 2014. LCLs were treated with 1mM lithium for 7 days followed by microarray gene expression assay and validation by real-time quantitative PCR. Baseline differences between groups, as well as differences between vehicle- and lithium-treated cells within each group were analyzed. The biological significance of differentially expressed genes was examined by pathway enrichment analysis. No significant differences in baseline gene expression (adjusted p-value < 0.05) were detected between groups. Lithium treatment of LCLs from controls did not lead to any significant differences. However, lithium altered the expression of 236 genes in LCLs from patients; those genes were enriched for signaling pathways related to apoptosis. Among those genes, the alterations in the expression of PIK3CG, SERP1 and UPP1 were validated by real-time PCR. A significant correlation was also found between circadian functioning and CEBPG and FGF2 expression levels. In summary, our results suggest that lithium treatment induces expression changes in genes associated with the apoptosis pathway in BD LCLs. The more pronounced effects of lithium in patients compared to controls suggest a disease-specific effect of this drug. Copyright © 2017 Elsevier B.V. and ECNP. All rights reserved.

  16. Presynaptic dystroglycan-pikachurin complex regulates the proper synaptic connection between retinal photoreceptor and bipolar cells. (United States)

    Omori, Yoshihiro; Araki, Fumiyuki; Chaya, Taro; Kajimura, Naoko; Irie, Shoichi; Terada, Koji; Muranishi, Yuki; Tsujii, Toshinori; Ueno, Shinji; Koyasu, Toshiyuki; Tamaki, Yasuhiro; Kondo, Mineo; Amano, Shiro; Furukawa, Takahisa


    Dystroglycan (DG) is a key component of the dystrophin-glycoprotein complex (DGC) at the neuromuscular junction postsynapse. In the mouse retina, the DGC is localized at the presynapse of photoreceptor cells, however, the function of presynaptic DGC is poorly understood. Here, we developed and analyzed retinal photoreceptor-specific DG conditional knock-out (DG CKO) mice. We found that the DG CKO retina showed a reduced amplitude and a prolonged implicit time of the ERG b-wave. Electron microscopic analysis revealed that bipolar dendrite invagination into the photoreceptor terminus is perturbed in the DG CKO retina. In the DG CKO retina, pikachurin, a DG ligand in the retina, is markedly decreased at photoreceptor synapses. Interestingly, in the Pikachurin(-/-) retina, the DG signal at the ribbon synaptic terminus was severely reduced, suggesting that pikachurin is required for the presynaptic accumulation of DG at the photoreceptor synaptic terminus, and conversely DG is required for pikachurin accumulation. Furthermore, we found that overexpression of pikachurin induces formation and clustering of a DG-pikachurin complex on the cell surface. The Laminin G repeats of pikachurin, which are critical for its oligomerization and interaction with DG, were essential for the clustering of the DG-pikachurin complex as well. These results suggest that oligomerization of pikachurin and its interaction with DG causes DG assembly on the synapse surface of the photoreceptor synaptic terminals. Our results reveal that the presynaptic interaction of pikachurin with DG at photoreceptor terminals is essential for both the formation of proper photoreceptor ribbon synaptic structures and normal retinal electrophysiology.

  17. Heterogeneous incidence and propagation of spreading depolarizations (United States)

    Kaufmann, Dan; Theriot, Jeremy J; Zyuzin, Jekaterina; Service, C Austin; Chang, Joshua C; Tang, Y Tanye; Bogdanov, Vladimir B; Multon, Sylvie; Schoenen, Jean; Ju, Y Sungtaek


    Spreading depolarizations are implicated in a diverse set of neurologic diseases. They are unusual forms of nervous system activity in that they propagate very slowly and approximately concentrically, apparently not respecting the anatomic, synaptic, functional, or vascular architecture of the brain. However, there is evidence that spreading depolarizations are not truly concentric, isotropic, or homogeneous, either in space or in time. Here we present evidence from KCl-induced spreading depolarizations, in mouse and rat, in vivo and in vitro, showing the great variability that these depolarizations can exhibit. This variability can help inform the mechanistic understanding of spreading depolarizations, and it has implications for their phenomenology in neurologic disease. PMID:27562866

  18. Bipolar disorders

    DEFF Research Database (Denmark)

    Vieta, Eduard; Berk, Michael; Schulze, Thomas G


    Bipolar disorders are chronic and recurrent disorders that affect >1% of the global population. Bipolar disorders are leading causes of disability in young people as they can lead to cognitive and functional impairment and increased mortality, particularly from suicide and cardiovascular disease...... and accurate diagnosis is difficult in clinical practice as the onset of bipolar disorder is commonly characterized by nonspecific symptoms, mood lability or a depressive episode, which can be similar in presentation to unipolar depression. Moreover, patients and their families do not always understand...... a bipolar disorder from other conditions. Optimal early treatment of patients with evidence-based medication (typically mood stabilizers and antipsychotics) and psychosocial strategies is necessary....

  19. Current density and catalyst-coated membrane resistance distribution of hydro-formed metallic bipolar plate fuel cell short stack with 250 cm2 active area (United States)

    Haase, S.; Moser, M.; Hirschfeld, J. A.; Jozwiak, K.


    An automotive fuel cell with an active area of 250 cm2 is investigated in a 4-cell short stack with a current and temperature distribution device next to the bipolar plate with 560 current and 140 temperature segments. The electrical conductivities of the bipolar plate and gas diffusion layer assembly are determined ex-situ with this current scan shunt module. The applied fuel cell consists of bipolar plates constructed of 75-μm-thick, welded stainless-steel foils and a graphitic coating. The electrical conductivities of the bipolar plate and gas diffusion layer assembly are determined ex-situ with this module with a 6% deviation in in-plane conductivity. The current density distribution is evaluated up to 2.4 A cm-2. The entire cell's investigated volumetric power density is 4.7 kW l-1, and its gravimetric power density is 4.3 kW kg-1 at an average cell voltage of 0.5 V. The current density distribution is determined without influencing the operating cell. In addition, the current density distribution in the catalyst-coated membrane and its effective resistivity distribution with a finite volume discretisation of Ohm's law are evaluated. The deviation between the current density distributions in the catalyst-coated membrane and the bipolar plate is determined.

  20. Reviewing metallic PEMFC bipolar plates

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Turner, J.A. [National Renewable Energy Laboratory, Golden, CO (United States)


    A bipolar plate is one of the most important components in a polymer exchange membrane fuel cell (PEMFC) stack and has multiple functions. Metallic bipolar plate candidates have advantages over composite rivals in excellent electrical and thermal conductivity, good mechanical strength, high chemical stability, very wide alloy choices, low cost and, most importantly, existing pathways for high-volume, high-speed mass production. The challenges with metallic bipolar plates are the higher contact resistance and possible corrosion products, which may contaminate the membrane electrode assembly. This review evaluates the candidate metallic and coating materials for bipolar plates and gives the perspective of the research trends. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  1. Bipolar Disorder. (United States)

    Spearing, Melissa

    Bipolar disorder, a brain disorder that causes unusual shifts in a person's mood, affects approximately one percent of the population. It commonly occurs in late adolescence and is often unrecognized. The diagnosis of bipolar disorder is made on the basis of symptoms, course of illness, and when possible, family history. Thoughts of suicide are…

  2. Molecular pathways involved in neuronal cell adhesion and membrane scaffolding contribute to schizophrenia and bipolar disorder susceptibility.

    LENUS (Irish Health Repository)

    O'Dushlaine, C


    Susceptibility to schizophrenia and bipolar disorder may involve a substantial, shared contribution from thousands of common genetic variants, each of small effect. Identifying whether risk variants map to specific molecular pathways is potentially biologically informative. We report a molecular pathway analysis using the single-nucleotide polymorphism (SNP) ratio test, which compares the ratio of nominally significant (P<0.05) to nonsignificant SNPs in a given pathway to identify the \\'enrichment\\' for association signals. We applied this approach to the discovery (the International Schizophrenia Consortium (n=6909)) and validation (Genetic Association Information Network (n=2729)) of schizophrenia genome-wide association study (GWAS) data sets. We investigated each of the 212 experimentally validated pathways described in the Kyoto Encyclopaedia of Genes and Genomes in the discovery sample. Nominally significant pathways were tested in the validation sample, and five pathways were found to be significant (P=0.03-0.001); only the cell adhesion molecule (CAM) pathway withstood conservative correction for multiple testing. Interestingly, this pathway was also significantly associated with bipolar disorder (Wellcome Trust Case Control Consortium (n=4847)) (P=0.01). At a gene level, CAM genes associated in all three samples (NRXN1 and CNTNAP2), which were previously implicated in specific language disorder, autism and schizophrenia. The CAM pathway functions in neuronal cell adhesion, which is critical for synaptic formation and normal cell signaling. Similar pathways have also emerged from a pathway analysis of autism, suggesting that mechanisms involved in neuronal cell adhesion may contribute broadly to neurodevelopmental psychiatric phenotypes.

  3. Quantum Stackelberg Duopoly Game in Depolarizing Channel

    International Nuclear Information System (INIS)

    Zhu Xia; Kuang Leman


    In this paper, we investigate the quantum Stackelberg duopoly (QSD) game in the noise environment with the depolarizing channel expressed by the Kraus-operator representation. It is found that the presence of the damping in the depolarizing channel always leads to the decrease of the quantities of the moves and payoffs of the two players in the QSD game. It is indicated that under certain conditions the first-mover advantage in the QSD game can be weakened due to the presence of the damping in the depolarizing channel.

  4. The nature of surround-induced depolarizing responses in goldfish cones

    NARCIS (Netherlands)

    Kraaij, D. A.; Spekreijse, H.; Kamermans, M.


    Cones in the vertebrate retina project to horizontal and bipolar cells and the horizontal cells feedback negatively to cones. This organization forms the basis for the center/surround organization of the bipolar cells, a fundamental step in the visual signal processing. Although the surround

  5. CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results

    International Nuclear Information System (INIS)

    Sommer, C. M.; Lemm, G.; Hohenstein, E.; Bellemann, N.; Stampfl, U.; Goezen, A. S.; Rassweiler, J.; Kauczor, H. U.; Radeleff, B. A.; Pereira, P. L.


    Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 ± 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 ± 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 ± 13.6 min and 43.7 ± 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 ± 8.8 months, local recurrence-free survival was 14.4 ± 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 ± 16.6 ml/min/1.73 m 2 before RF ablation vs. 47.2 ± 11.9 ml/min/1.73 m 2 after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

  6. CT-guided Bipolar and Multipolar Radiofrequency Ablation (RF Ablation) of Renal Cell Carcinoma: Specific Technical Aspects and Clinical Results

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, C. M., E-mail: [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Lemm, G.; Hohenstein, E. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany); Bellemann, N.; Stampfl, U. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Goezen, A. S.; Rassweiler, J. [Clinic for Urology, SLK Kliniken Heilbronn GmbH (Germany); Kauczor, H. U.; Radeleff, B. A. [University Hospital Heidelberg, INF 110, Department of Diagnostic and Interventional Radiology (Germany); Pereira, P. L. [Minimally Invasive Therapies and Nuclear Medicine, SLK Kliniken Heilbronn GmbH, Clinic for Radiology (Germany)


    Purpose. This study was designed to evaluate the clinical efficacy of CT-guided bipolar and multipolar radiofrequency ablation (RF ablation) of renal cell carcinoma (RCC) and to analyze specific technical aspects between both technologies. Methods. We included 22 consecutive patients (3 women; age 74.2 {+-} 8.6 years) after 28 CT-guided bipolar or multipolar RF ablations of 28 RCCs (diameter 2.5 {+-} 0.8 cm). Procedures were performed with a commercially available RF system (Celon AG Olympus, Berlin, Germany). Technical aspects of RF ablation procedures (ablation mode [bipolar or multipolar], number of applicators and ablation cycles, overall ablation time and deployed energy, and technical success rate) were analyzed. Clinical results (local recurrence-free survival and local tumor control rate, renal function [glomerular filtration rate (GFR)]) and complication rates were evaluated. Results. Bipolar RF ablation was performed in 12 procedures and multipolar RF ablation in 16 procedures (2 applicators in 14 procedures and 3 applicators in 2 procedures). One ablation cycle was performed in 15 procedures and two ablation cycles in 13 procedures. Overall ablation time and deployed energy were 35.0 {+-} 13.6 min and 43.7 {+-} 17.9 kJ. Technical success rate was 100 %. Major and minor complication rates were 4 and 14 %. At an imaging follow-up of 15.2 {+-} 8.8 months, local recurrence-free survival was 14.4 {+-} 8.8 months and local tumor control rate was 93 %. GFR did not deteriorate after RF ablation (50.8 {+-} 16.6 ml/min/1.73 m{sup 2} before RF ablation vs. 47.2 {+-} 11.9 ml/min/1.73 m{sup 2} after RF ablation; not significant). Conclusions. CT-guided bipolar and multipolar RF ablation of RCC has a high rate of clinical success and low complication rates. At short-term follow-up, clinical efficacy is high without deterioration of the renal function.

  7. Efficient treatment of aniline containing wastewater in bipolar membrane microbial electrolysis cell-Fenton system

    DEFF Research Database (Denmark)

    Li, Xiaohu; Jin, Xiangdan; Zhao, Nannan


    wastewater under an acidic condition maintained by the bipolar membrane. The aniline was effectively degraded following first-order kinetics at a rate constant of 0.0166 h−1 under an applied voltage of 0.5 V. Meanwhile, a total organic carbon (TOC) removal efficiency of 93.1 ± 1.2% was obtained, revealing...

  8. Spontaneous complement activation on human B cells results in localized membrane depolarization and the clustering of complement receptor type 2 and C3 fragments

    DEFF Research Database (Denmark)

    Løbner, Morten; Leslie, Robert G Q; Prodinger, Wolfgang M


    While our previous studies have demonstrated that complement activation induced by complement receptors type 2 (CR2/CD21) and 1 (CR1/CD35) results in C3-fragment deposition and membrane attack complex (MAC) formation in human B cells, the consequences of these events for B-cell functions remain u...

  9. Anticorrosion Coating of Carbon Nanotube/Polytetrafluoroethylene Composite Film on the Stainless Steel Bipolar Plate for Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Show


    Full Text Available Composite film of carbon nanotube (CNT and polytetrafluoroethylene (PTFE was formed from dispersion fluids of CNT and PTFE. The composite film showed high electrical conductivity in the range of 0.1–13 S/cm and hydrophobic nature. This composite film was applied to stainless steel (SS bipolar plates of the proton exchange membrane fuel cell (PEMFC as anticorrosion film. This coating decreased the contact resistance between the surface of the bipolar plate and the membrane electrode assembly (MEA of the PEMFC. The output power of the fuel cell is increased by 1.6 times because the decrease in the contact resistance decreases the series resistance of the PEMFC. Moreover, the coating of this composite film protects the bipolar plate from the surface corrosion.

  10. Losses of immunoreactive parvalbumin amacrine and immunoreactive alphaprotein kinase C bipolar cells caused by methylmercury chloride intoxication in the retina of the tropical fish Hoplias malabaricus

    Directory of Open Access Journals (Sweden)

    D.M.O. Bonci


    Full Text Available To quantify the effects of methylmercury (MeHg on amacrine and on ON-bipolar cells in the retina, experiments were performed in MeHg-exposed groups of adult trahiras (Hoplias malabaricus at two dose levels (2 and 6 µg/g, ip. The retinas of test and control groups were processed by mouse anti-parvalbumin and rabbit anti-alphaprotein kinase C (alphaPKC immunocytochemistry. Morphology and soma location in the inner nuclear layer were used to identify immunoreactive parvalbumin (PV-IR and alphaPKC (alphaPKC-IR in wholemount preparations. Cell density, topography and isodensity maps were estimated using confocal images. PV-IR was detected in amacrine cells in the inner nuclear layer and in displaced amacrine cells from the ganglion cell layer, and alphaPKC-IR was detected in ON-bipolar cells. The MeHg-treated group (6 µg/g showed significant reduction of the ON-bipolar alphaPKC-IR cell density (mean density = 1306 ± 393 cells/mm² compared to control (1886 ± 892 cells/mm²; P < 0.001. The mean densities found for amacrine PV-IR cells in MeHg-treated retinas were 1040 ± 56 cells/mm² (2 µg/g and 845 ± 82 cells/mm² (6 µg/g, also lower than control (1312 ± 31 cells/mm²; P < 0.05, differently from the data observed in displaced PV-IR amacrine cells. These results show that MeHg changed the PV-IR amacrine cell density in a dose-dependent way, and reduced the density of alphaKC-IR bipolar cells at the dose of 6 µg/g. Further studies are needed to identify the physiological impact of these findings on visual function.

  11. Sensitive electrochemiluminescence biosensor based on Au-ITO hybrid bipolar electrode amplification system for cell surface protein detection. (United States)

    Wu, Mei-Sheng; Yuan, Da-Jing; Xu, Jing-Juan; Chen, Hong-Yuan


    Here we developed a novel hybrid bipolar electrode (BPE)-electrochemiluminescence (ECL) biosensor based on hybrid bipolar electrode (BPE) for the measurement of cancer cell surface protein using ferrocence (Fc) labeled aptamer as signal recognition and amplification probe. According to the electric neutrality of BPE, the cathode of U-shaped ITO BPE was electrochemically deposited by Au nanoparticles (NPs) to enhance its conductivity and surface area, decrease the overpotential of O2 reduction, which would correspondingly increase the oxidation current of Ru(bpy)3(2+)/tripropylamine (TPA) on the anode of BPE and resulting a ∼4-fold enhancement of ECL intensity. Then a signal amplification strategy was designed by introducing Fc modified aptamer on the anode surface of BPE through hybridization for detecting the amount of mucin-1 on MCF-7 cells. The presence of Fc could not only inhibit the oxidation of Ru(bpy)3(2+) because of its lower oxidation potential, its oxidation product Fc(+) could also quench the ECL of Ru(bpy)3(2+)/TPA by efficient energy-transfer from the excited-state Ru(bpy)3(2+)* to Fc(+), making the ECL intensity greatly quenched. On the basis of the cathodic Au NPs induced ECL enhancing coupled with anodic Fc induced signal quenching amplification, the approach allowed detection of mucin-1 aptamer at a concentration down to 0.5 fM and was capable of detecting a minimum of 20 MCF-7 cells. Besides, the amount of mucin-1 on MCF-7 cells was calculated to be 9041 ± 388 molecules/cell. This approach therefore shows great promise in bioanalysis.

  12. Bipolar Disorder and Cancer

    Directory of Open Access Journals (Sweden)

    Sermin Kesebir


    Full Text Available Prevalence studies and studies on causation relations have shown that the relation between psychiatric disorders and chronic physical diseases is neglected. For heterogeneous diseases an increasing number of susceptibility variants are being defined. Alzheimer disease, bipolar disorder, breast and prostate cancer, coronary artery disease, Chron's disease, systemic lupus eritematosus, type 1 and type 2 diabetes mellitus are mentioned together with epigenetic concept. In acrocentric zone of chromosome 13, breast cancer, retinoblastoma, chronic Iymphocytic leukemia genes with B cells, dopamin loci of bipolar disorder are found together. Among bipolar and healthy individuals, an increase risk of breast cancer in female cases has been resported. On the other hand, psychosocial factors that affect stress and response to stress itself may be important variables in prognosis and progression of different cancer types. During the course of many cancer types –especially brain tumors- and during treatment of chemotherapeutic agents, bipolar symptomatology may appear. In this article, it is reviewed with relevant literature that whether an etiological relation between bipolar disorder and cancer exist and how both diseases affect each other's course and treatment.

  13. Fabrication of CNT Dispersion Fluid by Wet-Jet Milling Method for Coating on Bipolar Plate of Fuel Cell

    Directory of Open Access Journals (Sweden)

    Anas Almowarai


    Full Text Available Water based carbon nanotube (CNT dispersion was produced by wet-jet milling method. Commercial CNT was originally agglomerated at the particle size of less than 1 mm. The wet-jet milling process exfoliated CNTs from the agglomerates and dispersed them into water. Sedimentation of the CNTs in the dispersion fluid was not observed for more than a month. The produced CNT dispersion was characterized by the SEM and the viscometer. CNT/PTFE composite film was formed with the CNT dispersion in this study. The electrical conductivity of the composite film increased to 10 times when the CNT dispersion, which was produced by the wet-jet milling method, was used as a constituent of the film. Moreover, the composite film was applied to bipolar plate of fuel cell and increased the output power of the fuel cell to 1.3 times.

  14. Laminated exfoliated graphite composite-metal compositions for fuel cell flow field plate or bipolar plate applications (United States)

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z


    An electrically conductive laminate composition for fuel cell flow field plate or bipolar plate applications. The laminate composition comprises at least a thin metal sheet having two opposed exterior surfaces and a first exfoliated graphite composite sheet bonded to the first of the two exterior surfaces of the metal sheet wherein the exfoliated graphite composite sheet comprises: (a) expanded or exfoliated graphite and (b) a binder or matrix material to bond the expanded graphite for forming a cohered sheet, wherein the binder or matrix material is between 3% and 60% by weight based on the total weight of the first exfoliated graphite composite sheet. Preferably, the first exfoliated graphite composite sheet further comprises particles of non-expandable graphite or carbon in the amount of between 3% and 60% by weight based on the total weight of the non-expandable particles and the expanded graphite. Further preferably, the laminate comprises a second exfoliated graphite composite sheet bonded to the second surface of the metal sheet to form a three-layer laminate. Surface flow channels and other desired geometric features can be built onto the exterior surfaces of the laminate to form a flow field plate or bipolar plate. The resulting laminate has an exceptionally high thickness-direction conductivity and excellent resistance to gas permeation.

  15. Increased proliferation of late-born retinal progenitor cells by gestational lead exposure delays rod and bipolar cell differentiation. (United States)

    Chaney, Shawnta Y; Mukherjee, Shradha; Giddabasappa, Anand; Rueda, Elda M; Hamilton, W Ryan; Johnson, Jerry E; Fox, Donald A


    Studies of neuronal development in the retina often examine the stages of proliferation, differentiation, and synaptic development, albeit independently. Our goal was to determine if a known neurotoxicant insult to a population of retinal progenitor cells (RPCs) would affect their eventual differentiation and synaptic development. To that end, we used our previously published human equivalent murine model of low-level gestational lead exposure (GLE). Children and animals with GLE exhibit increased scotopic electroretinogram a- and b-waves. Adult mice with GLE exhibit an increased number of late-born RPCs, a prolonged period of RPC proliferation, and an increased number of late-born rod photoreceptors and rod and cone bipolar cells (BCs), with no change in the number of late-born Müller glial cells or early-born neurons. The specific aims of this study were to determine whether increased and prolonged RPC proliferation alters the spatiotemporal differentiation and synaptic development of rods and BCs in early postnatal GLE retinas compared to control retinas. C57BL/6N mouse pups were exposed to lead acetate via drinking water throughout gestation and until postnatal day 10, which is equivalent to the human gestation period for retinal neurogenesis. RT-qPCR, immunohistochemical analysis, and western blots of well-characterized, cell-specific genes and proteins were performed at embryonic and early postnatal ages to assess rod and cone photoreceptor differentiation, rod and BC differentiation and synaptic development, and Müller glial cell differentiation. Real-time quantitative PCR (RT-qPCR) with the rod-specific transcription factors Nrl , Nr2e3 , and Crx and the rod-specific functional gene Rho , along with central retinal confocal studies with anti-recoverin and anti-rhodopsin antibodies, revealed a two-day delay in the differentiation of rod photoreceptors in GLE retinas. Rhodopsin immunoblots supported this conclusion. No changes in glutamine synthetase gene

  16. First Observation of a Snake Depolarizing Resonance

    International Nuclear Information System (INIS)

    Phelps, R.; Anferov, V.; Blinov, B.; Crandell, D.; Koutin, S.; Krisch, A.; Liu, T.; Ratner, L.; Wong, V.; Chu, C.; Lee, S.; Rinckel, T.; Schwandt, P.; Sperisen, F.; Stephenson, E.; von Przewoski, B.; Sato, H.


    Using a 104MeV stored polarized proton beam and a full Siberian snake, we recently found evidence for a so-called open-quotes snakeclose quotes depolarizing resonance. A full Siberian snake forces the spin tune ν s to be a half integer. Thus, if the vertical betatron tune ν y is set near a quarter integer, then the ν s =n±2ν y second-order snake resonance can depolarize the beam. Indeed, with a full Siberian snake, we found a deep depolarization dip when ν y was equal to 4.756; moreover, when ν y was changed to 4.781, the deep dip disappeared and the polarization was preserved. copyright 1997 The American Physical Society

  17. Weak Depolarizing Resonances in the 3-TeV VLHC Booster

    International Nuclear Information System (INIS)

    Anferov, V.A.


    The possibility of polarized-proton-beam acceleration in the proposed low-field 3-TeV VLHC booster is considered. We find that the low-field combined function magnets in the booster's long FODO cells cause an inadvertent cancellation of most depolarizing fields due to a mechanism suggested earlier by Chao and Derbenev [Part.Accel.36, 25 (1991)]. The strongest spin-depolarizing resonances in the 3-TeV booster seem to be similar in strength to those in the 250-GeV RHIC. Moreover, the strength of the 3-TeV booster's strongest intrinsic depolarizing resonances decreases with energy, in contrast with the energy growth of the depolarizing resonance's strength in most proton synchrotrons. copyright 1999 The American Physical Society

  18. Teardown analysis of a ten cell bipolar nickel-hydrogen battery (United States)

    Manzo, M. A.; Gonzalez-Sanabria, O. D.; Herzau, J. S.; Scaglione, L. J.


    Design studies have identified bipolar nickel-hydrogen batteries as an attractive storage option for high power, high voltage applications. A pre-prototype Ni-H2 battery was designed, assembled and tested in the early phases of a concept verification program. The initial stack was built with available hardware and components from past programs. The stack performed well. After 2000 low-earth-orbit cycles the stack was dismantled in order to allow evaluation and analysis of the design and components. The results of the teardown analysis and recommended modifications are discussed.

  19. Characterization and processing of bipolar semiconductor electrodes in a dual electrolyte cell

    Energy Technology Data Exchange (ETDEWEB)

    Cattarin, S.; Musiani, M.M. [Istituto di Polarografia ed Elettrochimica Preparativa del C.N.R., Padova (Italy)


    Photoelectrochemical (PEC) processes may be induced at both faces of a bipolar semiconductor electrode without application of metal contacts by using the dual electrolyte arrangement -- metal/electrolyte 1/semiconductor/electrolyte 2/metal -- and by applying a voltage to the end metal electrodes. The possibilities of semiconductor characterization (determination of action spectra and doping level) and processing (photoetching and metal electrodeposition) are discussed on the basis of model experiments, performed with n-InP wafers. The advantages of this approach over traditional PEC and electroless techniques are discussed with particular emphasis on etching.

  20. Depolarization of diffusing spins by paramagnetic impurities

    International Nuclear Information System (INIS)

    Schillaci, M.E.; Hutson, R.L.; Heffner, R.H.; Leon, M.; Dodds, S.A.; Estle, T.L.


    We study the depolarization of diffusing spins (muons) interacting with dilute paramagnetic impurities in a solid using a simple computational model which properly treats the muon motion and preserves correct muon-impurity distances. Long-range (dipolar) and nearest-neighbor (contact) interactions are treated together. Diffusion parameters are deduced and model comparisons made for AuGd (300 ppm). (orig.)

  1. Neutron Depolarization in Submicron Ferromagnetic Materials

    NARCIS (Netherlands)

    Rekveldt, M.Th.


    The neutron depolarization technique is based on the loss of polarization of a polarized neutron beam after transmission through ferromagnetic substances. This loss, caused by Larmor precession in individual domains, determines the mean domain size, the mean square direction cosines of the domains

  2. Characterization of depolarization-coupled release of glutamate from cultured mouse cerebellar granule cells using DL-threo-beta-benzyloxyaspartate (DL-TBOA) to distinguish between the vesicular and cytoplasmic pools

    DEFF Research Database (Denmark)

    Bak, Lasse K; Schousboe, Arne; Waagepetersen, Helle S


    Release of preloaded [3H]D-aspartate in response to depolarization induced by N-methyl-D-aspartate (NMDA) or the endogenous agonist glutamate was characterized using cultured glutamatergic cerebellar granule neurons. Release from the vesicular and the cytoplasmic glutamate pools, respectively, wa...

  3. Bipolar Disorder (United States)

    ... one or other traumatic event Drug or alcohol abuse Complications Left untreated, bipolar disorder can result in serious problems that affect every area of your life, such as: Problems related to drug and alcohol use Suicide or suicide attempts Legal or financial problems Damaged ...

  4. Chlorovirus-mediated membrane depolarization of Chlorella alters secondary active transport of solutes. (United States)

    Agarkova, Irina; Dunigan, David; Gurnon, James; Greiner, Timo; Barres, Julia; Thiel, Gerhard; Van Etten, James L


    Paramecium bursaria chlorella virus 1 (PBCV-1) is the prototype of a family of large, double-stranded DNA, plaque-forming viruses that infect certain eukaryotic chlorella-like green algae from the genus Chlorovirus. PBCV-1 infection results in rapid host membrane depolarization and potassium ion release. One interesting feature of certain chloroviruses is that they code for functional potassium ion-selective channel proteins (Kcv) that are considered responsible for the host membrane depolarization and, as a consequence, the efflux of potassium ions. This report examines the relationship between cellular depolarization and solute uptake. Annotation of the virus host Chlorella strain NC64A genome revealed 482 putative transporter-encoding genes; 224 are secondary active transporters. Solute uptake experiments using seven radioactive compounds revealed that virus infection alters the transport of all the solutes. However, the degree of inhibition varied depending on the solute. Experiments with nystatin, a drug known to depolarize cell membranes, produced changes in solute uptake that are similar but not identical to those that occurred during virus infection. Therefore, these studies indicate that chlorovirus infection causes a rapid and sustained depolarization of the host plasma membrane and that this depolarization leads to the inhibition of secondary active transporters that changes solute uptake.

  5. Effect of surface treatment on the interfacial contact resistance and corrosion resistance of Fe–Ni–Cr alloy as a bipolar plate for polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Yang, Meijun; Zhang, Dongming


    The bipolar plate is an important component of the PEMFC (polymer electrolyte membrane fuel cell) because it supplies the pathway of electron flow between each unit cell. Fe–Ni–Cr alloy is considered as a good candidate material for bipolar plate, but it is limited to use as a bipolar plate due to its high ICR (interfacial contact resistance) and corrosion problem. In order to explore a cost-effective method on surface modification, various chemical and electrochemical treatments are performed on Fe–Ni–Cr alloy to acquire the effect of the surface modification on the ICR and corrosion behavior. The ICR and corrosion resistance of Fe–Ni–Cr alloy can be effectively controlled by the chemical treatment of immersion in the mixed acid solution with 10 vol% HNO 3 , 2 vol% HCl and 1 vol% HF for 10 min at 65 °C and then was placed in 30 vol% HNO 3 solution for 5 min. The chemical treatment is more effective on reducing ICR and improving corrosion resistance than that of electrochemical methods (be carried out in the 2 mol/L H 2 SO 4 solution with the electrical potential from −0.4 V to 0.6 V) for Fe–Ni–Cr alloy as a bipolar plate for polymer electrolyte membrane fuel cells. - Highlights: • The procedure of the surface treatments on Fe–Ni–Cr alloy as bipolar plate was described in detail. • Effects of various surface treatments on the interfacial contact resistivity and corrosion behavior were discussed. • The mechanism of the surface modification was particularly analyzed

  6. A micro-scale model for predicting contact resistance between bipolar plate and gas diffusion layer in PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.; Lin, G.; Shih, A.J.; Hu, S.J. [Department of Mechanical Engineering, The University of Michigan, Ann Arbor, MI 48109-2125 (United States)


    Contact resistance between the bipolar plate (BPP) and the gas diffusion layer (GDL) in a proton exchange membrane (PEM) fuel cell constitutes a significant portion of the overall fuel cell electrical resistance under the normal operation conditions. Most current methods for contact resistance estimation are experimental and there is a lack of well developed theoretical methods. A micro-scale numerical model is developed to predict the electrical contact resistance between BPP and GDL by simulating the BPP surface topology and GDL structure and numerically determining the status for each contact spot. The total resistance and pressure are obtained by considering all contact spots as resistances in parallel and summing the results together. This model shows good agreements with experimental results. Influences of BPP surface roughness parameters on contact resistance are also studied. This model is beneficial in understanding the contact behavior between BPP and GDL and can be integrated with other fuel cell simulations to predict the overall performance of PEM fuel cells. (author)

  7. Development and characterisation of electrically conductive polymeric-based blends for proton exchange membrane fuel cell bipolar plates

    Energy Technology Data Exchange (ETDEWEB)

    Bouatia, S.; Mighri, F. [Center for Applied Research on Polymers and Composites, CREPEC, Department of Chemical Engineering, Laval University, Quebec (Canada); Bousmina, M. [Center for Applied Research on Polymers and Composites, CREPEC, Department of Chemical Engineering, Laval University, Quebec (Canada); Canada Research Chair on Polymer Physics and Nanomaterials, Department of Chemical Engineering, Laval University, Quebec (Canada); Hassan II Academy of Science and Technology, Rabat (Morocco)


    The main objective of this work was to develop films with controlled dimensions for proton exchange membrane fuel cell (PEMFC) bipolar plates (BPPs) using the twin-screw extrusion process. These films consisted of a low-viscosity polyethylene terephthalate (PET) in which a mixture of high specific surface area carbon black (CB) and synthetic flake graphite (GR) were dispersed. A third conductive additive, consisting of silver-coated glass particles (SCG) or multi-walled carbon nanotubes (MWCNT), was also added at a low concentration (5 wt.-%) in order to study its synergistic effect on the PET-based blend electrical conductivity. As the developed blends had to meet properties suitable for PEMFC bipolar plate applications, they were characterised for their electrical through-plane resistivity, mechanical properties and oxygen permeability. Through-plane electrical resistivity of about 0.3 {omega}.cm and oxygen permeation rate of 3.5 x 10{sup -8} cc cm{sup -2} s{sup -1} were obtained for only 30 wt.-% of a 60:40 mixture of CB/GR conductive additives. Although the substitution of 5 wt.-% of CB/GR by the same amount of MWCNT had no significant effect on BPPs' electrical resistivity, it helped to improve their mechanical properties and especially their oxygen permeation, which was decreased from 3.5 x 10{sup -8} cc cm{sup -2} s{sup -1} to around 0.6 x 10{sup -8} cc cm{sup -2}s{sup -1}. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  8. Neutrality in bipolar structures

    DEFF Research Database (Denmark)

    Montero, Javier; Rodríguez, J. Tinguaro; Franco, Camilo


    In this paper, we want to stress that bipolar knowledge representation naturally allows a family of middle states which define as a consequence different kinds of bipolar structures. These bipolar structures are deeply related to the three types of bipolarity introduced by Dubois and Prade, but our...... approach offers a systematic explanation of how such bipolar structures appear and can be identified....

  9. Recording, analysis, and interpretation of spreading depolarizations in neurointensive care

    DEFF Research Database (Denmark)

    Dreier, Jens P; Fabricius, Martin; Ayata, Cenk


    Spreading depolarizations (SD) are waves of abrupt, near-complete breakdown of neuronal transmembrane ion gradients, are the largest possible pathophysiologic disruption of viable cerebral gray matter, and are a crucial mechanism of lesion development. Spreading depolarizations are increasingly r...

  10. A Simulation Tool for Geometrical Analysis and Optimization of Fuel Cell Bipolar Plates: Development, Validation and Results

    Directory of Open Access Journals (Sweden)

    Javier Pino


    Full Text Available Bipolar plates (BPs are one of the most important components in Proton Exchange Membrane Fuel Cells (PEMFC due to the numerous functions they perform. The objective of the research work described in this paper was to develop a simplified and validated method based on Computational Fluid Dynamics (CFD, aimed at the analysis and study of the influence of geometrical parameters of BPs on the operation of a cell. A complete sensibility analysis of the influence of dimensions and shape of the BP can be obtained through a simplified CFD model without including the complexity of other components of the PEMFC. This model is compared with the PEM Fuel Cell Module of the FLUENT software, which includes the physical and chemical phenomena relevant in PEMFCs. Results with both models regarding the flow field inside the channels and local current densities are obtained and compared. The results show that it is possible to use the simple model as a standard tool for geometrical analysis of BPs, and results of a sensitivity analysis using the simplified model are presented and discussed.

  11. Effect of graphite addition into mill scale waste as a potential bipolar plates material of proton exchange membrane fuel cells (United States)

    Khaerudini, D. S.; Prakoso, G. B.; Insiyanda, D. R.; Widodo, H.; Destyorini, F.; Indayaningsih, N.


    Bipolar plates (BPP) is a vital component of proton exchange membrane fuel cells (PEMFC), which supplies fuel and oxidant to reactive sites, remove reaction products, collects produced current and provide mechanical support for the cells in the stack. This work concerns the utilization of mill scale, a by-product of iron and steel formed during the hot rolling of steel, as a potential material for use as BPP in PEMFC. On the other hand, mill scale is considered a very rich in iron source having characteristic required such as for current collector in BPP and would significantly contribute to lower the overall cost of PEMFC based fuel cell systems. In this study, the iron reach source of mill scale powder, after sieving of 150 mesh, was mechanically alloyed with the carbon source containing 5, 10, and 15 wt.% graphite using a shaker mill for 3 h. The mixed powders were then pressed at 300 MPa and sintered at 900 °C for 1 h under inert gas atmosphere. The structural changes of powder particles during mechanical alloying and after sintering were studied by X-ray diffractometry, optical microscopy, scanning electron microscopy, and microhardness measurement. The details of the presence of iron, carbon, and iron carbide (Fe-C) as the products of reactions as well as sufficient mechanical strength of the sintered materials were presented in this report.

  12. Bipolar Treatment: Are Bipolar I and Bipolar II Treated Differently? (United States)

    ... The diagnosis and management of bipolar I and bipolar II disorders: Clinical practice update. Mayo Clinic Proceedings. 2017;92:1532. Haynes PL, et al. Social rhythm therapies for mood disorders: An update. Current Psychiatry Reports. ...

  13. Resonant depolarization in electron storage rings equipped with ''siberia snakes''

    International Nuclear Information System (INIS)

    Buon, J.


    Resonant depolarization induced by field errors and quantum emissions in an electron ring equipped with two ''siberian snakes'' is investigated with a first order perturbation calculation. It is shown that this depolarization is not reduced by the snakes when the operating energy is set out of the depolarization resonances [fr

  14. A scattering model for rain depolarization (United States)

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


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

  15. Entanglement degradation in depolarizing light scattering

    International Nuclear Information System (INIS)

    Aiello, A.; Woerdman, J.P.


    Full text: In the classical regime, when a beam of light is scattered by a medium, it may emerge partially or completely depolarized depending on the optical properties of the medium. Correspondingly, in the quantum regime, when an entangled two-photon pair is scattered, the classical depolarization may result in an entanglement degradation. Here, relations between photon scattering, entanglement and multi-mode detection are investigated. We establish a general framework in which one- and two-photon elastic scattering processes can be discussed, and we focus on the study of the intrinsic entanglement degradation caused by a multi-mode detection. We show that any multi-mode scattered state cannot maximally violate the Bell-CHSH inequality because of the momentum spread. The results presented here have general validity and can be applied to both deterministic and random scattering processes. (author)

  16. Correction of Depolarizing Resonances in ELSA (United States)

    Steier, C.; Husmann, D.


    The 3.5 GeV electron stretcherring ELSA (ELectron Stretcher Accelerator) at Bonn University is operational since 1987, both as a continuous beam facility for external fixed target experiments and as a partially dedicated synchrotron light source. For the external experiments an upgrade to polarized electrons is under way. One source of polarized electrons (GaAs crystal, photoeffect using circular polarized laser light) is operational. The studies of minimizing the losses in polarization degree due to crossing of depolarizing resonances that necessarily exist in circular accelerators (storagerings) just started recently. Calculations concerning different correction schemes for the depolarizing resonances in ELSA are presented, and first results of measurements are shown (done by means of a Møller polarimeter in one of the external beamlines).

  17. Electron beam depolarization in a damping ring

    International Nuclear Information System (INIS)

    Minty, M.


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

  18. Bipolar electrochemistry. (United States)

    Fosdick, Stephen E; Knust, Kyle N; Scida, Karen; Crooks, Richard M


    A bipolar electrode (BPE) is an electrically conductive material that promotes electrochemical reactions at its extremities (poles) even in the absence of a direct ohmic contact. More specifically, when sufficient voltage is applied to an electrolyte solution in which a BPE is immersed, the potential difference between the BPE and the solution drives oxidation and reduction reactions. Because no direct electrical connection is required to activate redox reactions, large arrays of electrodes can be controlled with just a single DC power supply or even a battery. The wireless aspect of BPEs also makes it possible to electrosynthesize and screen novel materials for a wide variety of applications. Finally, bipolar electrochemistry enables mobile electrodes, dubbed microswimmers, that are able to move freely in solution. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. μ+ depolarization in AlGd alloys

    International Nuclear Information System (INIS)

    Kohn, S.; Brown, J.A.; Heffner, R.H.; Huang, C.Y.; Kitchens, T.A. Jr.; Leon, M.; Olsen, C.E.; Schillaci, M.E.


    The μ + depolarization rate in dilute AlGd alloys containing 50 and 450 atomic ppm Gd was measured in a transverse field of 80 Oe over the temperature range 6-300 K. For both alloys, Λ increased dramatically above 200 K, reaching values of 0.69 and 0.93 μs -1 , respectively, near room temperature. The results are interpreted as providing evidence for a thermally-activated trapping mechanism. (Auth.)

  20. Transtorno bipolar

    Directory of Open Access Journals (Sweden)

    Alda Martin


    Full Text Available Os resultados de estudos de famílias sugerem que o transtorno bipolar tenha uma base genética. Essa hipótese foi reforçada em estudos de adoção e de gêmeos. A herança do transtorno bipolar é complexa, envolve vários genes, além de apresentar heterogeneidade e interação entre fatores genéticos e não-genéticos. Achados, que já foram replicados, já implicaram os cromossomos 4, 12, 18 e 21, entre outros, na busca por genes de suscetibilidade. Os resultados mais promissores foram obtidos através de estudos de ligação. Por outro lado, os estudos de associação geraram dados interessantes, mas ainda vagos. Os estudos de populações de pacientes homogêneos e a melhor definição do fenótipo deverão contribuir para avanços futuros. A identificação dos genes relacionados ao transtorno bipolar irá permitir o melhor entendimento e tratamento dessa doença.

  1. Neutron depolarization in compressed ferrite powders

    International Nuclear Information System (INIS)

    Rekveldt, M.Th.; Kraan, W.H.


    The polarization change of a polarized neutron beam after transmission through a partly magnetized ferromagnetic material can be described by a (3x3) depolarization matrix. This matrix can be expressed in terms of domain quantities such as the reduced mean magnetization M, the mean domain size delta and the mean square direction cosinus γsub(y) of the inner magnetization within the domain, and can be used for measuring magnetic properties of ferromagnetic materials. In the underlying depolarization theory it is assumed that no correlations exist between the direction of the spontaneous magnetization Bs in neighbouring domains, and between the direction of Bs and the individual domain sizes. In order to extend the measuring method for ferromagnetic materials, measurements have been made with different compressed ferrite powders assuming that the mean domain size is equal to the mean particle size. The neutron depolarization matrix is measured as a function of an alternative external magnetic field and interpreted in terms of m, γsub(y), and delta. The possibilities and limitations of the measuring method are discussed

  2. Compton effect thermally activated depolarization dosimeter (United States)

    Moran, Paul R.


    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.

  3. Cell therapy in the treatment of bipolar mania in an animal model: a proof of concept study

    Directory of Open Access Journals (Sweden)

    Bruna M. Ascoli


    Full Text Available Abstract Introduction The rationale of mesenchymal stem cells (MSCs as a novel therapeutic approach in certain neurodegenerative diseases is based on their ability to promote neurogenesis. Hippocampal atrophy has been related to bipolar disorder (BD in preclinical, imaging and postmortem studies. Therefore, the development of new strategies to stimulate the neurogenesis process in BD is crucial. Objectives To investigate the behavioral and neurochemical changes induced by transplantation of MSCs in a model of mania-like behavior induced by lisdexamfetamine dimesylate (LDX. Methods Wistar rats (n=65 received one oral daily dose of LDX (10 mg/kg or saline for 14 days. On the 8th day of treatment, the animals additionally received intrahippocampal saline or MSC (1 µL containing 25,000 cells or lithium (47.5 mg/kg as an internal experimental control. Two hours after the last administration, behavioral and neurochemical analyses were performed. Results LDX-treated rats had increased locomotor activity compared to saline-saline rats (p=0.004, and lithium reversed LDX-related hyperactive behavior (p0.05 in the hippocampus of rats. Conclusion Even though these results suggest that a single intrahippocampal injection of MSCs was not helpful to treat hyperactivity induced by LDX and neither influenced BDNF secretion, we cannot rule out the possible therapeutic effects of MSCs. Further research is required to determine direct effects of LDX on brain structures as well as in other pathophysiological targets related to BD.

  4. Optimization of electrical conduction and passivity properties of stainless steels used for PEM fuel cell bipolar plates

    International Nuclear Information System (INIS)

    Andre, J.


    Among the new technologies for energy for sustainable development, PEMFC (proton exchange membrane fuel cells) offer seducing aspects. However, in order to make this technology fit large scale application requirements, it has to comply with stringent cost, performance, and durability criteria. In such a frame, the goal of this work was to optimize electrical conduction properties and passivity of stainless steels for the conception of PEMFC bipolar plates, used instead of graphite, the reference material. This work presents the possible ways of performance loss when using stainless steels and some methods to solve this problem. Passive film properties were studied, as well as their modifications by low cost industrial surface treatments, without deposition. Ex situ characterizations of corrosion resistance and electrical conduction were performed. Electrochemical impedance spectroscopy, water analysis, surface analysis by microscopy and photoelectron spectroscopy allowed to study the impact of ageing on two alloys in different states, and several conditions representative of an exposure to PEMFC media. Correlations between semi-conductivity properties, composition, and structure of passive layers were considered, but not leading to clear identification of all parameters responsible for electrical conduction and passivity. The plate industrial state is not convenient for direct use in fuel cell to comply with durability and performance requirements. A surface modification studied improves widely electrical conduction at initial state. The performance is degraded with ageing, but maintaining a level higher than the initial industrial state. This treatment increases also corrosion resistance, particularly on the anode side. (author)

  5. The retina of the shovel-nosed ray, Rhinobatos batillum (Rhinobatidae): morphology and quantitative analysis of the ganglion, amacrine and bipolar cell populations. (United States)

    Collin, S P


    A light microscopy study of the retina of the shovel-nosed ray, Rhinobatos batillum (Rhinobatidae) has revealed a duplex retina with a rod to cone ratio between 4:1 and 6:1. The inner nuclear layer consists of three layers of large horizontal cells, tightly packed, stellate bipolar cells, and up to three substrata of amacrine cells. The collaterals of the many supporting Müller cells project from the inner to the outer limiting membrane and divide the retina into many subunits. The cells of the ganglion cell layer are distributed into two layers, although a large proportion of ganglion cells are also displaced into the inner plexiform and inner nuclear layers. Topographic analysis of the cells in the ganglion cell layer, inner plexiform and inner nuclear layers reveals a number of regional specializations or "areae centrales". Ganglion cells were retrogradely-labelled with cobalt-lysine from the optic nerve, and three sub-populations of neurons characterized on their soma size and position. Small (20-50 microns2), large (80-300 microns2) and giant (greater than 300 microns2) sub-populations of ganglion cells each revealed distinct retinal specializations with peak densities of 3 x 10(3), 1.25 x 10(3) and 1.57 x 10(3) cells per mm2, respectively. Topographical comparison between Nissl-stained and retrogradely-labelled ganglion cell populations have established that a maximum of 20% in the "area centralis", and 75% in unspecialized, peripheral regions of the retina are non-ganglion cells. Out of a total of 210,566 cells in the ganglion cell layer, 49% were found to be non-ganglion cells. Iso-density contour maps of amacrine and bipolar cell distributions also reveal some specializations. These cell concentrations lie in corresponding regions to areas of increased density in the large and giant ganglion cell populations, suggesting some functional association.

  6. Mechanism of blue-light-induced plasma-membrane depolarization in etiolated cucumber hypocotyls (United States)

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


    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.

  7. Estimating Depolarization with the Jones Matrix Quality Factor (United States)

    Hilfiker, James N.; Hale, Jeffrey S.; Herzinger, Craig M.; Tiwald, Tom; Hong, Nina; Schöche, Stefan; Arwin, Hans


    Mueller matrix (MM) measurements offer the ability to quantify the depolarization capability of a sample. Depolarization can be estimated using terms such as the depolarization index or the average degree of polarization. However, these calculations require measurement of the complete MM. We propose an alternate depolarization metric, termed the Jones matrix quality factor, QJM, which does not require the complete MM. This metric provides a measure of how close, in a least-squares sense, a Jones matrix can be found to the measured Mueller matrix. We demonstrate and compare the use of QJM to other traditional calculations of depolarization for both isotropic and anisotropic depolarizing samples; including non-uniform coatings, anisotropic crystal substrates, and beetle cuticles that exhibit both depolarization and circular diattenuation.

  8. Unidirectional threshold switching in Ag/Si-based electrochemical metallization cells for high-density bipolar RRAM applications (United States)

    Wang, Chao; Song, Bing; Li, Qingjiang; Zeng, Zhongming


    We herein present a novel unidirectional threshold selector for cross-point bipolar RRAM array. The proposed Ag/amorphous Si based threshold selector showed excellent threshold characteristics in positive field, such as high selectivity ( 105), steep slope (type RRAM. By integrating a bipolar RRAM device with the selector, experiments showed that the undesired sneak was significantly suppressed, indicating its potentiality for high-density integrated nonvolatile memory applications.

  9. Transcriptomic Analysis of Induced Pluripotent Stem Cells Derived from Patients with Bipolar Disorder from an Old Order Amish Pedigree.

    Directory of Open Access Journals (Sweden)

    Kwi Hye Kim

    Full Text Available Fibroblasts from patients with Type I bipolar disorder (BPD and their unaffected siblings were obtained from an Old Order Amish pedigree with a high incidence of BPD and reprogrammed to induced pluripotent stem cells (iPSCs. Established iPSCs were subsequently differentiated into neuroprogenitors (NPs and then to neurons. Transcriptomic microarray analysis was conducted on RNA samples from iPSCs, NPs and neurons matured in culture for either 2 weeks (termed early neurons, E or 4 weeks (termed late neurons, L. Global RNA profiling indicated that BPD and control iPSCs differentiated into NPs and neurons at a similar rate, enabling studies of differentially expressed genes in neurons from controls and BPD cases. Significant disease-associated differences in gene expression were observed only in L neurons. Specifically, 328 genes were differentially expressed between BPD and control L neurons including GAD1, glutamate decarboxylase 1 (2.5 fold and SCN4B, the voltage gated type IV sodium channel beta subunit (-14.6 fold. Quantitative RT-PCR confirmed the up-regulation of GAD1 in BPD compared to control L neurons. Gene Ontology, GeneGo and Ingenuity Pathway Analysis of differentially regulated genes in L neurons suggest that alterations in RNA biosynthesis and metabolism, protein trafficking as well as receptor signaling pathways may play an important role in the pathophysiology of BPD.

  10. Development of a brazing process for the production of water- cooled bipolar plates made of chromium-coated metal foils for PEM fuel cells

    International Nuclear Information System (INIS)

    Mueller, M; Hoehlich, D; Scharf, I; Lampke, T; Hollaender, U; Maier, H J


    Beside lithium batteries, PEM fuel cells are the most promising strategy as a power source to achieve the targets for introducing and increasing the usage of electric vehicles. Due to limited space and weight problems, water cooled, metallic bipolar plates in a fuel cell metal stack are preferred in motor vehicles. These plates are stamped metal sheets with a complex structure, interconnected media-tight. To meet the multiple tasks and requirements in use, complex and expensive combinations of materials are currently in use (carbon fiber composites, graphite, gold-plated nickel, stainless and acid resistant steel). The production of such plates is expensive as it is connected with considerable effort or the usage of precious metals. As an alternative, metalloid nitrides (CrN, VN, W 2 N, etc.) show a high chemical resistance, hardness and a good conductivity. So this material category meets the basic requirements of a top layer. However, the standard methods for their production (PVD, CVD) are expensive and have a slow deposition rate and a lower layer thicknesses. Because of these limitations, a full functionality over the life cycle of a bipolar plate is not guaranteed. The contribution shows the development and quantification of an alternative production process for bipolar plates. The expectation is to get significant advantages from the combination of chromium electrodeposition and thermochemical treatment to form chromium nitrides. Both processes are well researched and suitable for series production. The thermochemical treatment of the chromium layer also enables a process-integrated brazing. (paper)

  11. C-reactive protein and white blood cell levels in schizophrenia, bipolar disorders and depression - associations with mortality and psychiatric outcomes

    DEFF Research Database (Denmark)

    Horsdal, H T; Köhler-Forsberg, O; Benros, Michael E


    BACKGROUND: Mental disorders have been associated with increased levels of inflammatory markers, which can affect disease trajectories. We aimed to assess levels of C-reactive protein (CRP) and white blood cells (WBC) across individuals with schizophrenia, bipolar disorder, and depression......, and to investigate associations with subsequent psychiatric admission and mortality. METHODS: We identified all adults in the Central Denmark Region during 2000-2012 with a first diagnosis of schizophrenia, bipolar disorder, or depression and a baseline measurement of CRP and/or WBC count. We followed.......5mg/L) (particularly during manic states, 3.9mg/L), followed by schizophrenia (3.1mg/L), and depression (2.8mg/L), while baseline WBC count did not differ (median 7.1×10(9)/L). Elevated CRP levels were associated with increased all-cause mortality by adjusted HRs of 1.56 (95% CI: 1.02-2.38) for levels...

  12. Three-terminal heterojunction bipolar transistor solar cell for high-efficiency photovoltaic conversion. (United States)

    Martí, A; Luque, A


    Here we propose, for the first time, a solar cell characterized by a semiconductor transistor structure (n/p/n or p/n/p) where the base-emitter junction is made of a high-bandgap semiconductor and the collector is made of a low-bandgap semiconductor. We calculate its detailed-balance efficiency limit and prove that it is the same one than that of a double-junction solar cell. The practical importance of this result relies on the simplicity of the structure that reduces the number of layers that are required to match the limiting efficiency of dual-junction solar cells without using tunnel junctions. The device naturally emerges as a three-terminal solar cell and can also be used as building block of multijunction solar cells with an increased number of junctions.

  13. Pharmacological analysis of the activation and receptor properties of the tonic GABA(CR current in retinal bipolar cell terminals.

    Directory of Open Access Journals (Sweden)

    Stefanie M Jones

    Full Text Available GABAergic inhibition in the central nervous system (CNS can occur via rapid, transient postsynaptic currents and via a tonic increase in membrane conductance, mediated by synaptic and extrasynaptic GABA(A receptors (GABA(ARs respectively. Retinal bipolar cells (BCs exhibit a tonic current mediated by GABA(CRs in their axon terminal, in addition to synaptic GABA(AR and GABA(CR currents, which strongly regulate BC output. The tonic GABA(CR current in BC terminals (BCTs is not dependent on vesicular GABA release, but properties such as the alternative source of GABA and the identity of the GABA(CRs remain unknown. Following a recent report that tonic GABA release from cerebellar glial cells is mediated by Bestrophin 1 anion channels, we have investigated their role in non-vesicular GABA release in the retina. Using patch-clamp recordings from BCTs in goldfish retinal slices, we find that the tonic GABA(CR current is not reduced by the anion channel inhibitors NPPB or flufenamic acid but is reduced by DIDS, which decreases the tonic current without directly affecting GABA(CRs. All three drugs also exhibit non-specific effects including inhibition of GABA transporters. GABA(CR ρ subunits can form homomeric and heteromeric receptors that differ in their properties, but BC GABA(CRs are thought to be ρ1-ρ2 heteromers. To investigate whether GABA(CRs mediating tonic and synaptic currents may differ in their subunit composition, as is the case for GABA(ARs, we have examined the effects of two antagonists that show partial ρ subunit selectivity: picrotoxin and cyclothiazide. Tonic and synaptic GABA(CR currents were differentially affected by both drugs, suggesting that a population of homomeric ρ1 receptors contributes to the tonic current. These results extend our understanding of the multiple forms of GABAergic inhibition that exist in the CNS and contribute to visual signal processing in the retina.

  14. Tune space manipulations in jumping depolarizing resonances

    International Nuclear Information System (INIS)

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


    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 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

  15. Spreading depolarizations and late secondary insults after traumatic brain injury

    DEFF Research Database (Denmark)

    Hartings, Jed A; Strong, Anthony J; Fabricius, Martin


    Here we investigated the incidence of cortical spreading depolarizations (spreading depression and peri-infarct depolarization) after traumatic brain injury (TBI) and their relationship to systemic physiologic values during neurointensive care. Subdural electrode strips were placed on peri......-contusional cortex in 32 patients who underwent surgical treatment for TBI. Prospective electrocorticography was performed during neurointensive care with retrospective analysis of hourly nursing chart data. Recordings were 84 hr (median) per patient and 2,503 hr in total. In 17 patients (53%), 280 spreading...... depolarizations (spreading depressions and peri-infarct depolarizations) were observed. Depolarizations occurred in a bimodal pattern with peak incidence on days 1 and 7. The probability of a depolarization occurring increased significantly as a function of declining mean arterial pressure (MAP; R(2) = 0.78; p...

  16. Miniaturized polymer electrolyte fuel cell (PEFC) stack using micro structured bipolar plate

    Energy Technology Data Exchange (ETDEWEB)

    Veziridis, Z; Scherer, G G; Marmy, Ch; Glaus, F [Paul Scherrer Inst. (PSI), Villigen (Switzerland)


    In Polymer Electrolyte Fuel Cell (PEFC) technology the reducing of volume and mass of the fuel cell stack and the improvement of catalyst utilization are of great interest. These parameters affect applicability and system cost. In this work we present an alternative way for reducing the stack volume by combining gas distribution and catalytic active area in one plate. Micro machined glassy carbon electrodes serve as support material for the platinum catalyst, as well as gas distributor at the same time. A comparison of these electrodes with conventional platinum-black gas diffusion electrodes under fuel cell conditions shows that the new system is a promising electrode type for enhanced power density and catalyst utilization. (author) 3 figs., 5 refs.

  17. Bipolar polaron pair recombination in P3HT/PCBM solar cells

    DEFF Research Database (Denmark)

    Kupijai, Alexander J.; Behringer, Konstantin M.; Corazza, Michael


    . However, in organic devices the nature of the dominant spin-dependent processes is still subject to considerable debate. Using multi-frequency pulsed electrically detected magnetic resonance (pEDMR), we show that the spin-dependent response of P3HT/PCBM solar cells at low temperatures is governed...... of the electron spin on charge transport which can be exploited in spintronic devices or to improve solar cell eciencies. Magnetic resonance techniques are particularly helpful to elucidate the microscopic structure of paramagnetic states in semiconductors as well as the transport processes they are involved in...

  18. Surface composition effect of nitriding Ni-free stainless steel as bipolar plate of polymer electrolyte fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yang; Shironita, Sayoko [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Nakatsuyama, Kunio [Nakatsuyama Heat Treatment Co., Ltd., 1-1089-10, Nanyou, Nagaoka, Niigata 940-1164 (Japan); Souma, Kenichi [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Hitachi Industrial Equipment Systems Co., Ltd., 3 Kanda Neribei, Chiyoda, Tokyo 101-0022 (Japan); Umeda, Minoru, E-mail: [Nagaoka University of Technology, 1603-1, Kamitomioka, Nagaoka, Niigata 940-2188 (Japan)


    Graphical abstract: The anodic current densities in the passive region of nitrided SUS445-N stainless steel are lower than those of a non heat-treated SUS445 stainless steel and heat-treated SUS445-Ar stainless steel under an Ar atmosphere. It shows a better corrosion resistance for the SUS445 stainless steel after the nitriding heat treatment. - Highlights: • The nitriding heat treatment was carried out using Ni-free SUS445 stainless steel. • The corrosion resistance of the nitrided SUS445-N stainless steel was improved. • The structure of the nitrided SUS445-N stainless steel changed from α-Fe to γ-Fe. • The surface elemental components present in the steels affect the corrosion resistance. - Abstract: In order to increase the corrosion resistance of low cost Ni-free SUS445 stainless steel as the bipolar plate of a polymer electrolyte fuel cell, a nitriding surface treatment experiment was carried out in a nitrogen atmosphere under vacuum conditions, while an Ar atmosphere was used for comparison. The electrochemical performance, microstructure, surface chemical composition and morphology of the sample before and after the electrochemical measurements were investigated using linear sweep voltammetry (LSV), X-ray diffraction (XRD), glow discharge optical emission spectroscopy (GDS) and laser scanning microscopy (LSM) measurements. The results confirmed that the nitriding heat treatment not only increased the corrosion resistance, but also improved the surface conductivity of the Ni-free SUS445 stainless steel. In contrast, the corrosion resistance of the SUS445 stainless steel decreased after heat treatment in an Ar atmosphere. These results could be explained by the different surface compositions between these samples.

  19. Bipolar Role for Myelo-Monocytic Cells in Autoimmune Diseases and Psychiatric Disorders

    NARCIS (Netherlands)

    W. Beumer (Wouter)


    markdownabstract__Abstract__ The immune system is a complex system of tissue with cells and messenger molecules interacting to protect an organism against pathogens. Autoimmunity is the failure of the immune system to recognize its own constituent parts as harmless self and therefore it leads to

  20. Strong Resilience of Topological Codes to Depolarization

    Directory of Open Access Journals (Sweden)

    H. Bombin


    Full Text Available The inevitable presence of decoherence effects in systems suitable for quantum computation necessitates effective error-correction schemes to protect information from noise. We compute the stability of the toric code to depolarization by mapping the quantum problem onto a classical disordered eight-vertex Ising model. By studying the stability of the related ferromagnetic phase via both large-scale Monte Carlo simulations and the duality method, we are able to demonstrate an increased error threshold of 18.9(3% when noise correlations are taken into account. Remarkably, this result agrees within error bars with the result for a different class of codes—topological color codes—where the mapping yields interesting new types of interacting eight-vertex models.

  1. Bipolar disorder in adolescence. (United States)

    DeFilippis, Melissa; Wagner, Karen Dineen


    Bipolar disorder is a serious psychiatric condition that may have onset in childhood. It is important for physicians to recognize the symptoms of bipolar disorder in children and adolescents in order to accurately diagnose this illness early in its course. Evidence regarding the efficacy of various treatments is necessary to guide the management of bipolar disorder in youth. For example, several medications commonly used for adults with bipolar disorder have not shown efficacy for children and adolescents with bipolar disorder. This article reviews the prevalence, diagnosis, course, and treatment of bipolar disorder in children and adolescents and provides physicians with information that will aid in diagnosis and treatment.

  2. Electronic monitoring in bipolar disorder

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria


    generated data (e.g. the number of text messages sent/day; the number of incoming and outgoing calls/day; the number of changes in cell tower IDs/day; and voice features) seem to reflect clinically assessed depressive and manic symptoms in bipolar disorder; 3) smartphone-based electronic self-monitoring had...

  3. High rate lithium/thionyl chloride bipolar battery development (United States)

    Russell, P. G.; Goebel, F.

    The lithium/thionyl chloride ( {Li}/{SOCl2}) electrochemistry is capable of providing high power and high specific power, especially under pulse discharge conditions, when cells containing thin components are arranged in a bipolar configuration. This paper describes recent work concerned with bipolar cell design, cathode evaluation, component manufacturing methods, and the assembly and testing of bipolar modules containing up to 150 cells for Sonobuoy application.

  4. High rate lithium-thionyl chloride bipolar battery development

    Energy Technology Data Exchange (ETDEWEB)

    Russell, P.G.; Goebel, F. [Yardney Technical Products, Inc., Pawcatuck, CT (United States)


    The lithium/thionyl chloride system is capable of providing both high power and high energy density when cells containing thin components are arranged in a bipolar configuration. Electrode current densities in excess of 300mA/cm{sup 2} are achieved during pulse discharge. The present work is concerned with bipolar cell design, cathode evaluation, component manufacturing methods, and the assembly and testing of bipolar modules containing up to 150 cells.

  5. High rate lithium/thionyl chloride bipolar battery development

    Energy Technology Data Exchange (ETDEWEB)

    Russell, P.G. [Yardney Technical Products, Inc., Pawcatuck, CT (United States); Goebel, F. [Yardney Technical Products, Inc., Pawcatuck, CT (United States)


    The lithium/thionyl chloride (Li/SOCl{sub 2}) electrochemistry is capable of providing high power and high specific power, especially under pulse discharge conditions, when cells containing thin components are arranged in a bipolar configuration. This paper describes recent work concerned with bipolar cell design, cathode evaluation, component manufacturing methods, and the assembly and testing of bipolar modules containing up to 150 cells for Sonobuoy application. (orig.)

  6. 2017 Bipolar Plate Workshop Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Kopasz, John P. [Argonne National Lab. (ANL), Argonne, IL (United States); Benjamin, Thomas G. [Argonne National Lab. (ANL), Argonne, IL (United States); Schenck, Deanna [Argonne National Lab. (ANL), Argonne, IL (United States)


    The Bipolar Plate (BP) Workshop was held at USCAR1 in Southfield, Michigan on February 14, 2017 and included 63 participants from industry, government agencies, universities, and national laboratories with expertise in the relevant fields. The objective of the workshop was to identify research and development (R&D) needs, in particular early-stage R&D, for bipolar plates for polymer electrolyte membrane (PEM) fuel cells for transportation applications. The focus of the workshop was on materials, manufacturing, and design aspects of bipolar plates with the goal of meeting DOE’s 2020 bipolar plate targets. Of special interest was the cost target of ≤$3/kW for the bipolar plate.

  7. Neutron depolarization studies on magnetization process using pulsed polarized neutrons

    International Nuclear Information System (INIS)

    Mitsuda, Setsuo; Endoh, Yasuo


    Neutron depolarization experiments investigating the magnetization processes have been performed by using pulsed polarized neutrons for the first time. Results on both quenched and annealed ferromagnets of Fe 85 Cr 15 alloy indicate the significant difference in the wavelength dependence of depolarization between them. It also constitutes the experimental demonstration of the theoretical prediction of Halpern and Holstein. (author)

  8. Single neuron dynamics during experimentally induced anoxic depolarization

    NARCIS (Netherlands)

    Zandt, B.; Stigen, Tyler; ten Haken, Bernard; Netoff, Theoden; van Putten, Michel Johannes Antonius Maria


    We studied single neuron dynamics during anoxic depolarizations, which are often observed in cases of neuronal energy depletion. Anoxic and similar depolarizations play an important role in several pathologies, notably stroke, migraine, and epilepsy. One of the effects of energy depletion was

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

    DEFF Research Database (Denmark)

    Ayata, Cenk; Lauritzen, Martin


    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...

  10. Depolarization Lidar Determination of Cloud-Base Microphysical Properties

    NARCIS (Netherlands)

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


    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

  11. Depolarization of ultracold neutrons during their storage in material bottles

    International Nuclear Information System (INIS)

    Serebrov, A.P.; Lasakov, M.S.; Vassiljev, A.V.; Krasnoschekova, I.A.; Rudnev, Yu.P.; Fomin, A.K.; Varlamov, V.E.; Geltenbort, P.; Butterworth, J.; Young, A.R.; Pesavento, U.


    The depolarization of ultracold neutrons (UCN) during their storage in traps has been investigated. The neutron spin-flip probability for the materials studied amounts to ∼(1-2)x10 -5 per collision and does not depend on the temperature. The possible connection between the phenomenon of UCN depolarization and that of anomalous losses is discussed

  12. Depolarization of ultracold neutrons during their storage in material bottles

    Energy Technology Data Exchange (ETDEWEB)

    Serebrov, A.P.; Lasakov, M.S.; Vassiljev, A.V.; Krasnoschekova, I.A.; Rudnev, Yu.P.; Fomin, A.K.; Varlamov, V.E.; Geltenbort, P.; Butterworth, J.; Young, A.R.; Pesavento, U


    The depolarization of ultracold neutrons (UCN) during their storage in traps has been investigated. The neutron spin-flip probability for the materials studied amounts to {approx}(1-2)x10{sup -5} per collision and does not depend on the temperature. The possible connection between the phenomenon of UCN depolarization and that of anomalous losses is discussed.

  13. Single residue AAV capsid mutation improves transduction of photoreceptors in the Abca4-/- mouse and bipolar cells in the rd1 mouse and human retina ex vivo. (United States)

    De Silva, Samantha R; Charbel Issa, Peter; Singh, Mandeep S; Lipinski, Daniel M; Barnea-Cramer, Alona O; Walker, Nathan J; Barnard, Alun R; Hankins, Mark W; MacLaren, Robert E


    Gene therapy using adeno-associated viral (AAV) vectors for the treatment of retinal degenerations has shown safety and efficacy in clinical trials. However, very high levels of vector expression may be necessary for the treatment of conditions such as Stargardt disease where a dual vector approach is potentially needed, or in optogenetic strategies for end-stage degeneration in order to achieve maximal light sensitivity. In this study, we assessed two vectors with single capsid mutations, rAAV2/2(Y444F) and rAAV2/8(Y733F) in their ability to transduce retina in the Abca4 -/- and rd1 mouse models of retinal degeneration. We noted significantly increased photoreceptor transduction using rAAV2/8(Y733F) in the Abca4 -/- mouse, in contrast to previous work where vectors tested in this model have shown low levels of photoreceptor transduction. Bipolar cell transduction was achieved following subretinal delivery of both vectors in the rd1 mouse, and via intravitreal delivery of rAAV2/2(Y444F). The successful use of rAAV2/8(Y733F) to target bipolar cells was further validated on human tissue using an ex vivo culture system of retinal explants. Capsid mutant AAV vectors transduce human retinal cells and may be particularly suited to treat retinal degenerations in which high levels of transgene expression are required.

  14. Protective effect of the poly(ADP-ribose polymerase inhibitor PJ34 on mitochondrial depolarization-mediated cell death in hepatocellular carcinoma cells involves attenuation of c-Jun N-terminal kinase-2 and protein kinase B/Akt activation

    Directory of Open Access Journals (Sweden)

    Radnai Balazs


    Full Text Available Abstract Background 2,4-Dimethoxyphenyl-E-4-arylidene-3-isochromanone (IK11 was previously described to induce apoptotic death of A431 tumor cells. In this report, we investigated the molecular action of IK11 in the HepG2 human hepatocellular carcinoma cell line to increase our knowledge of the role of poly (ADP-ribose-polymerase (PARP, protein kinase B/Akt and mitogen activated protein kinase (MAPK activation in the survival and death of tumor cells and to highlight the possible role of PARP-inhibitors in co-treatments with different cytotoxic agents in cancer therapy. Results We found that sublethal concentrations of IK11 prevented proliferation, migration and entry of the cells into their G2 phase. At higher concentrations, IK11 induced reactive oxygen species (ROS production, mitochondrial membrane depolarization, activation of c-Jun N-terminal kinase 2 (JNK2, and substantial loss of HepG2 cells. ROS production appeared marginal in mediating the cytotoxicity of IK11 since N-acetyl cysteine was unable to prevent it. However, the PARP inhibitor PJ34, although not a ROS scavenger, strongly inhibited both IK11-induced ROS production and cell death. JNK2 activation seemed to be a major mediator of the effect of IK11 since inhibition of JNK resulted in a substantial cytoprotection while inhibitors of the other kinases failed to do so. Inhibition of Akt slightly diminished the effect of IK11, while the JNK and Akt inhibitor and ROS scavenger trans-resveratrol completely protected against it. Conclusions These results indicate significant involvement of PARP, a marginal role of ROS and a pro-apoptotic role of Akt in this system, and raise attention to a novel mechanism that should be considered when cancer therapy is augmented with PARP-inhibition, namely the cytoprotection by inhibition of JNK2.

  15. Cytokines in bipolar disorder

    DEFF Research Database (Denmark)

    Munkholm, Klaus; Vinberg, Maj; Vedel Kessing, Lars


    BACKGROUND: Current research and hypothesis regarding the pathophysiology of bipolar disorder suggests the involvement of immune system dysfunction that is possibly related to disease activity. Our objective was to systematically review evidence of cytokine alterations in bipolar disorder according...... to affective state. METHODS: We conducted a systemtic review of studies measuring endogenous cytokine concentrations in patients with bipolar disorder and a meta-analysis, reporting results according to the PRISMA statement. RESULTS: Thirteen studies were included, comprising 556 bipolar disorder patients...

  16. Two regulatory RNA elements affect TisB-dependent depolarization and persister formation. (United States)

    Berghoff, Bork A; Hoekzema, Mirthe; Aulbach, Lena; Wagner, E Gerhart H


    Bacterial survival strategies involve phenotypic diversity which is generated by regulatory factors and noisy expression of effector proteins. The question of how bacteria exploit regulatory RNAs to make decisions between phenotypes is central to a general understanding of these universal regulators. We investigated the TisB/IstR-1 toxin-antitoxin system of Escherichia coli to appreciate the role of the RNA antitoxin IstR-1 in TisB-dependent depolarization of the inner membrane and persister formation. Persisters are phenotypic variants that have become transiently drug-tolerant by arresting growth. The RNA antitoxin IstR-1 sets a threshold for TisB-dependent depolarization under DNA-damaging conditions, resulting in two sub-populations: polarized and depolarized cells. Furthermore, our data indicate that an inhibitory 5' UTR structure in the tisB mRNA serves as a regulatory RNA element that delays TisB translation to avoid inappropriate depolarization when DNA damage is low. Investigation of the persister sub-population further revealed that both regulatory RNA elements affect persister levels as well as persistence time. This work provides an intriguing example of how bacteria exploit regulatory RNAs to control phenotypic heterogeneity. © 2016 John Wiley & Sons Ltd.

  17. Highly conductive, multi-layer composite precursor composition to fuel cell flow field plate or bipolar plate (United States)

    Jang, Bor Z [Centerville, OH; Zhamu, Aruna [Centerville, OH; Guo, Jiusheng [Centerville, OH


    This invention provides a moldable, multiple-layer composite composition, which is a precursor to an electrically conductive composite flow field plate or bipolar plate. In one preferred embodiment, the composition comprises a plurality of conductive sheets and a plurality of mixture layers of a curable resin and conductive fillers, wherein (A) each conductive sheet is attached to at least one resin-filler mixture layer; (B) at least one of the conductive sheets comprises flexible graphite; and (C) at least one resin-filler mixture layer comprises a thermosetting resin and conductive fillers with the fillers being present in a sufficient quantity to render the resulting flow field plate or bipolar plate electrically conductive with a conductivity no less than 100 S/cm and thickness-direction areal conductivity no less than 200 S/cm.sup.2.

  18. Nutrition and Bipolar Depression. (United States)

    Beyer, John L; Payne, Martha E


    As with physical conditions, bipolar disorder is likely to be impacted by diet and nutrition. Patients with bipolar disorder have been noted to have relatively unhealthy diets, which may in part be the reason they also have an elevated risk of metabolic syndrome and obesity. An improvement in the quality of the diet should improve a bipolar patient's overall health risk profile, but it may also improve their psychiatric outcomes. New insights into biological dysfunctions that may be present in bipolar disorder have presented new theoretic frameworks for understanding the relationship between diet and bipolar disorder. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Alterations in BDNF (brain derived neurotrophic factor) and GDNF (glial cell line-derived neurotrophic factor) serum levels in bipolar disorder: The role of lithium. (United States)

    Tunca, Zeliha; Ozerdem, Aysegul; Ceylan, Deniz; Yalçın, Yaprak; Can, Güneş; Resmi, Halil; Akan, Pınar; Ergör, Gül; Aydemir, Omer; Cengisiz, Cengiz; Kerim, Doyuran


    Brain-derived neurotrophic factor (BDNF) has been consistently reported to be decreased in mania or depression in bipolar disorders. Evidence suggests that Glial cell line-derived neurotrophic factor (GDNF) has a role in the pathogenesis of mood disorders. Whether GDNF and BDNF act in the same way across different episodes in bipolar disorders is unclear. BDNF and GDNF serum levels were measured simultaneously by enzyme-linked immunosorbent assay (ELISA) method in 96 patients diagnosed with bipolar disorder according to DSM-IV (37 euthymic, 33 manic, 26 depressed) in comparison to 61 healthy volunteers. SCID- I and SCID-non patient version were used for clinical evaluation of the patients and healthy volunteers respectively. Correlations between the two trophic factor levels, and medication dose, duration and serum levels of lithium or valproate were studied across different episodes of illness. Patients had significantly lower BDNF levels during mania and depression compared to euthymic patients and healthy controls. GDNF levels were not distinctive. However GDNF/BDNF ratio was higher in manic state compared to euthymia and healthy controls. Significant negative correlation was observed between BDNF and GDNF levels in euthymic patients. While BDNF levels correlated positively, GDNF levels correlated negatively with lithium levels. Regression analysis confirmed that lithium levels predicted only GDNF levels positively in mania, and negatively in euthymia. Small sample size in different episodes and drug-free patients was the limitation of thestudy. Current data suggests that lithium exerts its therapeutic action by an inverse effect on BDNF and GDNF levels, possibly by up-regulating BDNF and down-regulating GDNF to achieve euthymia. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Stitching Type Large Aperture Depolarizer for Gas Monitoring Imaging Spectrometer (United States)

    Liu, X.; Li, M.; An, N.; Zhang, T.; Cao, G.; Cheng, S.


    To increase the accuracy of radiation measurement for gas monitoring imaging spectrometer, it is necessary to achieve high levels of depolarization of the incoming beam. The preferred method in space instrument is to introduce the depolarizer into the optical system. It is a combination device of birefringence crystal wedges. Limited to the actual diameter of the crystal, the traditional depolarizer cannot be used in the large aperture imaging spectrometer (greater than 100 mm). In this paper, a stitching type depolarizer is presented. The design theory and numerical calculation model for dual babinet depolarizer were built. As required radiometric accuracies of the imaging spectrometer with 250 mm × 46 mm aperture, a stitching type dual babinet depolarizer was design in detail. Based on designing the optimum structural parmeters the tolerance of wedge angle refractive index, and central thickness were given. The analysis results show that the maximum residual polarization degree of output light from depolarizer is less than 2 %. The design requirements of polarization sensitivity is satisfied.


    Directory of Open Access Journals (Sweden)

    X. Liu


    Full Text Available To increase the accuracy of radiation measurement for gas monitoring imaging spectrometer, it is necessary to achieve high levels of depolarization of the incoming beam. The preferred method in space instrument is to introduce the depolarizer into the optical system. It is a combination device of birefringence crystal wedges. Limited to the actual diameter of the crystal, the traditional depolarizer cannot be used in the large aperture imaging spectrometer (greater than 100 mm. In this paper, a stitching type depolarizer is presented. The design theory and numerical calculation model for dual babinet depolarizer were built. As required radiometric accuracies of the imaging spectrometer with 250 mm × 46 mm aperture, a stitching type dual babinet depolarizer was design in detail. Based on designing the optimum structural parmeters,the tolerance of wedge angle,refractive index, and central thickness were given. The analysis results show that the maximum residual polarization degree of output light from depolarizer is less than 2 %. The design requirements of polarization sensitivity is satisfied.

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

    International Nuclear Information System (INIS)

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


    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. (paper)

  3. Electronic monitoring in bipolar disorder. (United States)

    Faurholt-Jepsen, Maria


    Major reasons for the insufficient effects of current treatment options in bipolar disorder include delayed intervention for prodromal depressive and manic symptoms and decreased adherence to psychopharmacological treatment. The reliance on subjective information and clinical evaluations when diagnosing and assessing the severity of depressive and manic symptoms calls for less biased and more objective markers. By using electronic devices, fine-grained data on complex psychopathological aspects of bipolar disorder can be evaluated unobtrusively over the long term. Moreover, electronic data could possibly represent candidate markers of diagnosis and illness activity in bipolar disorder and allow for early and individualized intervention for prodromal symptoms outside clinical settings. 
The present dissertation concerns the use of electronic monitoring as a marker and treatment intervention in bipolar disorder and investigated the scientific literature and body of evidence within the area, which includes ten original study reports and two systematic reviews, one of which included a meta-analysis, conducted by the author of the dissertation. 
Taken together, the literature presented in this dissertation illustrates that 1) smartphone-based electronic self-monitoring of mood seems to reflect clinically assessed depressive and manic symptoms and enables the long-term characterization of mood

instability in bipolar disorder; 2) preliminary results suggest that smartphone-based automatically generated data (e.g. the number of text messages sent/day; the number of incoming and outgoing calls/day; the number of changes in cell tower IDs/day; and voice features) seem to reflect clinically assessed depressive and manic symptoms in bipolar disorder; 3) smartphone-based electronic self-monitoring had no effects on the severity of depressive and manic symptoms in bipolar disorder, according to a randomized controlled trial; and 4) electronic monitoring of psychomotor

  4. Bipolar soft connected, bipolar soft disconnected and bipolar soft compact spaces

    Directory of Open Access Journals (Sweden)

    Muhammad Shabir


    Full Text Available Bipolar soft topological spaces are mathematical expressions to estimate interpretation of data frameworks. Bipolar soft theory considers the core features of data granules. Bipolarity is important to distinguish between positive information which is guaranteed to be possible and negative information which is forbidden or surely false. Connectedness and compactness are the most important fundamental topological properties. These properties highlight the main features of topological spaces and distinguish one topology from another. Taking this into account, we explore the bipolar soft connectedness, bipolar soft disconnectedness and bipolar soft compactness properties for bipolar soft topological spaces. Moreover, we introduce the notion of bipolar soft disjoint sets, bipolar soft separation, and bipolar soft hereditary property and study on bipolar soft connected and disconnected spaces. By giving the detailed picture of bipolar soft connected and disconnected spaces we investigate bipolar soft compact spaces and derive some results related to this concept.

  5. Possible Depolarization Mechanism due to Low Beta Squeeze

    International Nuclear Information System (INIS)

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


    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 ν s0 ± nν x - ν z l = integer which while the same numerology as the well known sextupole resonance, can operate in the absence of sextupole elements

  6. Coupling between electroosmotically driven flow and bipolar faradaic depolarization processes in electron-conducting microchannels

    NARCIS (Netherlands)

    Qian, S.Z.; Duval, J.F.L.


    A quantitative theory is proposed for the analysis of steady electroosmotically driven flows within conducting cylindrical microchannels. Beyond a threshold value of the electric field applied in the electrolyte Solution and parallel to the conducting surface, electrochemical oxidation and reduction

  7. Genetics Home Reference: bipolar disorder (United States)

    ... Email Facebook Twitter Home Health Conditions Bipolar disorder Bipolar disorder Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Bipolar disorder is a mental health condition that causes extreme ...



    Pathan Dilnawaz N; Ziyaurrahaman A.R; Bhise K.S.


    Bipolar disorder (BD) is a severe psychiatric disorder that results in poor global functioning, reduced quality of life and high relapse rates. Research finds that many adults with bipolar disorder identify the onset of symptoms in childhood and adolescence, indicating the importance of early accurate diagnosis and treatment. Accurate diagnosis of mood disorders is critical for treatment to be effective. Distinguishing between major depression and bipolar disorders, especially the depressed p...

  9. Bipolar Disorder in Women

    Directory of Open Access Journals (Sweden)

    Sermin Kesebir


    Full Text Available The research on gender's role in bipolar disorders has drawn significant interest recently. The presentation and course of bipolar disorder differs between women and men. Women experience depressive episodes, dysphoric mood, mixed states, rapid cycling and seasonal patterns more often than men. Comorbidity, particularly thyroid disease, migraine, obesity, and anxiety disorders laso occur more frequently in women than men. On the other hand men with bipolar disorder are also more likely than women to have problems with drug or alcohol abuse. The pregnancy and postpartum period is a time of high risk for onset and recurrence of bipolar disorder in women.

  10. Orphan receptor GPR179 forms macromolecular complexes with components of metabotropic signaling cascade in retina ON-bipolar neurons. (United States)

    Orlandi, Cesare; Cao, Yan; Martemyanov, Kirill A


    In the mammalian retina, synaptic transmission between light-excited rod photoreceptors and downstream ON-bipolar neurons is indispensable for dim vision, and disruption of this process leads to congenital stationary night blindness in human patients. The ON-bipolar neurons use the metabotropic signaling cascade, initiated by the mGluR6 receptor, to generate depolarizing responses to light-induced changes in neurotransmitter glutamate release from the photoreceptor axonal terminals. Evidence for the identity of the components involved in transducing these signals is growing rapidly. Recently, the orphan receptor, GPR179, a member of the G protein-coupled receptor (GPCR) superfamily, has been shown to be indispensable for the synaptic responses of ON-bipolar cells. In our study, we investigated the interaction of GPR179 with principle components of the signal transduction cascade. We used immunoprecipitation and proximity ligation assays in transfected cells and native retinas to characterize the protein-protein interactions involving GPR179. The influence of cascade components on GPR179 localization was examined through immunohistochemical staining of the retinas from genetic mouse models. We demonstrated that, in mouse retinas, GPR179 forms physical complexes with the main components of the metabotropic cascade, recruiting mGluR6, TRPM1, and the RGS proteins. Elimination of mGluR6 or RGS proteins, but not TRPM1, detrimentally affects postsynaptic targeting or GPR179 expression. These observations suggest that the mGluR6 signaling cascade is scaffolded as a macromolecular complex in which the interactions between the components ensure the optimal spatiotemporal characteristics of signal transduction.

  11. Effect of microstructure of TiN film on properties as bipolar plate coatings in polymer electrolyte membrane fuel cell prepared by inductively coupled plasma assisted magnetron sputtering

    International Nuclear Information System (INIS)

    Feng, Kai; Li, Zhuguo


    As potential application in bipolar plate of polymer electrolyte membrane fuel cell, the microstructure, corrosion resistance and the electrical conductivity of titanium nitride (TiN) and Si doped titanium nitride (Ti 0.9 Si 0.1 N) films deposited by magnetron sputtering with different bias voltages are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscope (AFM), electrochemical test and four-point probe method, respectively. XRD, SEM and AFM results reveal that the texture and topography of TiN film depend on the bias voltage and incorporation of Si. When the bias voltage is − 20 V and − 30 V, the TiN and Ti 0.9 Si 0.1 N films exhibit a dense (111) plane preferred growth, denser structure and smoother surface topography. The potentiodynamic test results indicate that the TiN and Ti 0.9 Si 0.1 N films have higher chemical inertness and better corrosion resistance. The films can satisfy the requirement of current density for bipolar plate materials. Incorporation of Si element into TiN film makes the passive current density more stable. Four-point probe measurement results show that the resistivity of both TiN and Ti 0.9 Si 0.1 N films reaches minimum when the deposition bias voltage is − 20 V. - Highlights: • Dense TiN and Ti 0.9 Si 0.1 N films are deposited by magnetron sputtering. • Preferred growth orientation of TiN depends on the bias voltage and Si doping. • TiN and Ti 0.9 Si 0.1 N films have excellent corrosion resistance. • Surface conductivity of TiN and Ti 0.9 Si 0.1 N films evolves with bias voltage

  12. The study of electroplating trivalent CrC alloy coatings with different current densities on stainless steel 304 as bipolar plate of proton exchange membrane fuel cells

    International Nuclear Information System (INIS)

    Wang, Hsiang-Cheng; Hou, Kung-Hsu; Lu, Chen-En; Ger, Ming-Der


    In this study, the trivalent Cr–C coatings were electroplated on stainless steel 304 (SS304) substrates for an application in bipolar plates (BPPs) that was because of coating's excellent electric conductivity and corrosion resistance. The images of scanning electron microscope showed that the thickness of the coatings was between 1.4 and 11.4 μm, which increased with increase of coating current density. The surface morphology of Cr–C plated at coating current density of 10 A/dm 2 was smooth, crack- and pinhole-free, while cracks and pinholes appearing in networks were observed apparently in the deposits plated at a higher coating current density. Additionally, the C content in the coating decreased with increasing the coating current density. Moreover, the polarization curve with different coating current densities (10, 30, 50 A/dm 2 ) exhibited the coating prepared at 10 A/dm 2 and 10 min possessing the best corrosion resistance (I corr = 9.360 × 10 −8 A/cm 2 ). The contact resistance of Cr–C plated at coating current density of 10 A/dm 2 was the lowest (16.54 mΩ cm 2 at 150 N cm −2 ), which showed great potential of application. The single cell test with Cr–C coated SS304 prepared at coating current density of 10 A/dm 2 as BPPs showed the highest current density (about 791.532 mA/cm 2 ) and power density (about 270.150 mW/cm 2 ). - Highlights: • The Cr–C coatings on steel are electroplated for utilization as bipolar plate. • The electrical conductivity and corrosion resistance increase with carbon content. • The power density of Cr–C coated steel is superior to the bare steel

  13. Cerebrospinal fluid neural cell adhesion molecule levels and their correlation with clinical variables in patients with schizophrenia, bipolar disorder, and major depressive disorder. (United States)

    Hidese, Shinsuke; Hattori, Kotaro; Sasayama, Daimei; Miyakawa, Tomoko; Matsumura, Ryo; Yokota, Yuuki; Ishida, Ikki; Matsuo, Junko; Noda, Takamasa; Yoshida, Sumiko; Teraishi, Toshiya; Hori, Hiroaki; Ota, Miho; Kunugi, Hiroshi


    Neural cell adhesion molecule (NCAM) plays an important role in neural plasticity, and its altered function has been implicated in psychiatric disorders. However, previous studies have yielded inconsistent results on cerebrospinal fluid (CSF) NCAM levels in psychiatric disorders. The aim of our study was to examine CSF NCAM levels in patients with schizophrenia, bipolar disorder (BD), and major depressive disorder (MDD), and their possible relationship with clinical variables. The participants comprised 85 patients with schizophrenia, 57 patients with BD, 83 patients with MDD and 111 healthy controls, all matched for age, sex, and Japanese ethnicity. The CSF samples were drawn using a lumbar puncture and NCAM levels were quantified by an enzyme-linked immunosorbent assay. Analysis of covariance controlling for age and sex revealed that CSF NCAM levels were lower in all patients (p=0.033), and in those with BD (p=0.039), than in the controls. NCAM levels positively correlated with age in patients with BD (pdepressive symptom scores in patients with BD (p=0.040). In patients with schizophrenia, NCAM levels correlated negatively with negative symptom scores (p=0.029), and correlated positively with scores for cognitive functions such as category fluency (p=0.011) and letter fluency (p=0.023) scores. We showed that CSF NCAM levels were lower in psychiatric patients, particularly bipolar patients than in the controls. Furthermore, we found correlations of NCAM levels with clinical symptoms in patients with BD and in those with schizophrenia, suggesting the involvement of central NCAM in the symptom formation of severe psychiatric disorders. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. The study of electroplating trivalent CrC alloy coatings with different current densities on stainless steel 304 as bipolar plate of proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hsiang-Cheng [Graduate School of Defense Science, Chung Cheng Institute of Technology, National Defense University, Taoyuan, Taiwan (China); Hou, Kung-Hsu, E-mail: [Department of Power Vehicle and Systems Engineering, Chung Cheng Institute of Technology, National Defense University, Taoyuan, Taiwan (China); Lu, Chen-En [Graduate School of Defense Science, Chung Cheng Institute of Technology, National Defense University, Taoyuan, Taiwan (China); Ger, Ming-Der [Department of Applied Chemistry and Materials Engineering, Chung Cheng Institute of Technology, National Defense University, Taoyuan, Taiwan (China)


    In this study, the trivalent Cr–C coatings were electroplated on stainless steel 304 (SS304) substrates for an application in bipolar plates (BPPs) that was because of coating's excellent electric conductivity and corrosion resistance. The images of scanning electron microscope showed that the thickness of the coatings was between 1.4 and 11.4 μm, which increased with increase of coating current density. The surface morphology of Cr–C plated at coating current density of 10 A/dm{sup 2} was smooth, crack- and pinhole-free, while cracks and pinholes appearing in networks were observed apparently in the deposits plated at a higher coating current density. Additionally, the C content in the coating decreased with increasing the coating current density. Moreover, the polarization curve with different coating current densities (10, 30, 50 A/dm{sup 2}) exhibited the coating prepared at 10 A/dm{sup 2} and 10 min possessing the best corrosion resistance (I{sub corr} = 9.360 × 10{sup −8} A/cm{sup 2}). The contact resistance of Cr–C plated at coating current density of 10 A/dm{sup 2} was the lowest (16.54 mΩ cm{sup 2} at 150 N cm{sup −2}), which showed great potential of application. The single cell test with Cr–C coated SS304 prepared at coating current density of 10 A/dm{sup 2} as BPPs showed the highest current density (about 791.532 mA/cm{sup 2}) and power density (about 270.150 mW/cm{sup 2}). - Highlights: • The Cr–C coatings on steel are electroplated for utilization as bipolar plate. • The electrical conductivity and corrosion resistance increase with carbon content. • The power density of Cr–C coated steel is superior to the bare steel.

  15. Comparative familial aggregation of bipolar disorder in patients with bipolar I and bipolar II disorders. (United States)

    Parker, Gordon B; Romano, Mia; Graham, Rebecca K; Ricciardi, Tahlia


    We sought to quantify the prevalence and differential prevalence of a bipolar disorder among family members of patients with a bipolar I or II disorder. The sample comprised 1165 bipolar and 1041 unipolar patients, with the former then sub-typed as having either a bipolar I or II condition. Family history data was obtained via an online self-report tool. Prevalence of a family member having a bipolar disorder (of either sub-type) was distinctive (36.8%). Patients with a bipolar I disorder reported a slightly higher family history (41.2%) compared to patients with a bipolar II disorder (36.3%), and with both significantly higher than the rate of bipolar disorder in family members of unipolar depressed patients (18.5%). Findings support the view that bipolar disorder is heritable. The comparable rates in the two bipolar sub-types support the positioning of bipolar II disorder as a valid condition with strong genetic underpinnings.

  16. Condurango (Gonolobus condurango Extract Activates Fas Receptor and Depolarizes Mitochondrial Membrane Potential to Induce ROS-dependent Apoptosis in Cancer Cells in vitro CE-treatment on HeLa: a ROS-dependent mechanism

    Directory of Open Access Journals (Sweden)

    Kausik Bishayee


    Full Text Available Objectives: Condurango (Gonolobus condurango extract is used by complementary and alternative medicine (CAM practitioners as a traditional medicine, including homeopathy, mainly for the treatment of syphilis. Condurango bark extract is also known to reduce tumor volume, but the underlying molecular mechanisms still remain unclear. Methods: Using a cervical cancer cell line (HeLa as our model, the molecular events behind condurango extract’s (CE’s anticancer effect were investigated by using flow cytometry, immunoblotting and reverse transcriptase-polymerase chain reaction (RT-PCR. Other included cell types were prostate cancer cells (PC3, transformed liver cells (WRL-68, and peripheral blood mononuclear cells (PBMCs. Results: Condurango extract (CE was found to be cytotoxic against target cells, and this was significantly deactivated in the presence of N-acetyl cysteine (NAC, a scavenger of reactive oxygen species (ROS, suggesting that its action could be mediated through ROS generation. CE caused an increase in the HeLa cell population containing deoxyribonucleic acid (DNA damage at the G zero/Growth 1 (G0/G1 stage. Further, CE increased the tumor necrosis factor alpha (TNF-α and the fas receptor (FasR levels both at the ribonucleic acid (RNA and the protein levels, indicating that CE might have a cytotoxic mechanism of action. CE also triggered a sharp decrease in the expression of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB both at the RNA and the protein levels, a possible route to attenuation of B-cell lymphoma 2 (Bcl-2, and caused an opening of the mitochondrial membrane’s permeability transition (MPT pores, thus enhancing caspase activities. Conclusion: Overall, our results suggest possible pathways for CE mediated cytotoxicity in model cancer cells.

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

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


    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. Isoflurane depolarizes bronchopulmonary C neurons by inhibiting transient A-type and delayed rectifier potassium channels. (United States)

    Zhang, Zhenxiong; Zhuang, Jianguo; Zhang, Cancan; Xu, Fadi


    Inhalation of isoflurane (ISO), a widely used volatile anesthetic, can produce clinical tachypnea. In dogs, this response is reportedly mediated by bronchopulmonary C-fibers (PCFs), but the relevant mechanisms remain unclear. Activation of transient A-type potassium current (IA) channels and delayed rectifier potassium current (IK) channels hyperpolarizes neurons, and inhibition of both channels by ISO increases neural firing. Due to the presence of these channels in the cell bodies of rat PCFs, we determined whether ISO could stimulate PCFs to produce tachypnea in anesthetized rats, and, if so, whether this response resulted from ISO-induced depolarization of the pulmonary C neurons via the inhibition of IA and IK. We recorded ventilatory responses to 5% ISO exposure in anesthetized rats before and after blocking PCF conduction and the responses of pulmonary C neurons (extracellularly recorded) to ISO exposure. ISO-induced (1mM) changes in pulmonary C neuron membrane potential and IA/IK were tested using the perforated patch clamp technique. We found that: (1) ISO inhalation evoked a brief tachypnea (∼7s) and that this response disappeared after blocking PCF conduction; (2) the ISO significantly elevated (by 138%) the firing rate of most pulmonary C neurons (17 out of 21) in the nodose ganglion; and (3) ISO perfusion depolarized the pulmonary C neurons in the vitro and inhibited both IA and IK, and this evoked-depolarization was largely diminished after blocking both IA and IK. Our results suggest that ISO is able to stimulate PCFs to elicit tachypnea in rats, at least partly, via inhibiting IA and IK, thereby depolarizing the pulmonary C neurons. Copyright © 2013. Published by Elsevier B.V.

  19. Properties of Bipolar Fuzzy Hypergraphs


    Akram, M.; Dudek, W. A.; Sarwar, S.


    In this article, we apply the concept of bipolar fuzzy sets to hypergraphs and investigate some properties of bipolar fuzzy hypergraphs. We introduce the notion of $A-$ tempered bipolar fuzzy hypergraphs and present some of their properties. We also present application examples of bipolar fuzzy hypergraphs.

  20. Effect of assembly error of bipolar plate on the contact pressure distribution and stress failure of membrane electrode assembly in proton exchange membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dong' an; Peng, Linfa; Lai, Xinmin [State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240 (China)


    In practice, the assembly error of the bipolar plate (BPP) in a PEM fuel cell stack is unavoidable based on the current assembly process. However its effect on the performance of the PEM fuel cell stack is not reported yet. In this study, a methodology based on FEA model, ''least squares-support vector machine (LS-SVM)'' simulation and statistical analysis is developed to investigate the effect of the assembly error of the BPP on the pressure distribution and stress failure of membrane electrode assembly (MEA). At first, a parameterized FEA model of a metallic BPP/MEA assembly is established. Then, the LS-SVM simulation process is conducted based on the FEA model, and datasets for the pressure distribution and Von Mises stress of MEA are obtained, respectively for each assembly error. At last, the effect of the assembly error is obtained by applying the statistical analysis to the LS-SVM results. A regression equation between the stress failure and the assembly error is also built, and the allowed maximum assembly error is calculated based on the equation. The methodology in this study is beneficial to understand the mechanism of the assembly error and can be applied to guide the assembly process for the PEM fuel cell stack. (author)

  1. An improved model for predicting electrical contact resistance between bipolar plate and gas diffusion layer in proton exchange membrane fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zhiliang; Wang, Shuxin [School of Mechanical Engineering, Tianjin University, Tianjin 300072 (China); Zhou, Yuanyuan; Lin, Guosong; Hu, S. Jack [Department of Mechanical Engineering, The University of Michigan, Ann Arbor, MI 48109-2125 (United States)


    Electrical contact resistance between bipolar plates (BPPs) and gas diffusion layers (GDLs) in PEM fuel cells has attracted much attention since it is one significant part of the total contact resistance which plays an important role in fuel cell performance. This paper extends a previous model by Zhou et al. [Y. Zhou, G. Lin, A.J. Shih, S.J. Hu, J. Power Sources 163 (2007) 777-783] on the prediction of electrical contact resistance within PEM fuel cells. The original microscale numerical model was based on the Hertz solution for individual elastic contacts, assuming that contact bodies, GDL carbon fibers and BPP asperities are isotropic elastic half-spaces. The new model features a more practical contact by taking into account the bending behavior of carbon fibers as well as their anisotropic properties. The microscale single contact process is solved numerically using the finite element method (FEM). The relationship between the contact pressure and the electrical resistance at the GDL/BPP interface is derived by multiple regression models. Comparisons of the original model by Zhou et al. and the new model with experimental data show that the original model slightly overestimates the electrical contact resistance, whereas a better agreement with experimental data is observed using the new model. (author)

  2. Spin Depolarization due to Beam-Beam Interaction in NLC

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Kathleen A


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

  3. The continuum of spreading depolarizations in acute cortical lesion development

    DEFF Research Database (Denmark)

    Hartings, Jed A; Shuttleworth, C William; Kirov, Sergei A


    A modern understanding of how cerebral cortical lesions develop after acute brain injury is based on Aristides Leão's historic discoveries of spreading depression and asphyxial/anoxic depolarization. Treated as separate entities for decades, we now appreciate that these events define a continuum....... The causal role of these waves in lesion development has been proven by real-time monitoring of electrophysiology, blood flow, and cytotoxic edema. The spreading depolarization continuum further applies to other models of acute cortical lesions, suggesting that it is a universal principle of cortical lesion...

  4. Regulation of glycogen synthase kinase-3 during bipolar mania treatment. (United States)

    Li, Xiaohong; Liu, Min; Cai, Zhuoji; Wang, Gang; Li, Xiaohua


    Bipolar disorder is a debilitating psychiatric illness presenting with recurrent mania and depression. The pathophysiology of bipolar disorder is poorly understood, and molecular targets in the treatment of bipolar disorder remain to be identified. Preclinical studies have suggested that glycogen synthase kinase-3 (GSK3) is a potential therapeutic target in bipolar disorder, but evidence of abnormal GSK3 in human bipolar disorder and its response to treatment is still lacking. This study was conducted in acutely ill type I bipolar disorder subjects who were hospitalized for a manic episode. The protein level and the inhibitory serine phosphorylation of GSK3 in peripheral blood mononuclear cells of bipolar manic and healthy control subjects were compared, and the response of GSK3 to antimanic treatment was evaluated. The levels of GSK3α and GSK3β in this group of bipolar manic subjects were higher than healthy controls. Symptom improvement during an eight-week antimanic treatment with lithium, valproate, and atypical antipsychotics was accompanied by a significant increase in the inhibitory serine phosphorylation of GSK3, but not the total level of GSK3, whereas concomitant electroconvulsive therapy treatment during a manic episode appeared to dampen the response of GSK3 to pharmacological treatment. Results of this study suggest that GSK3 can be modified during the treatment of bipolar mania. This finding in human bipolar disorder is in agreement with preclinical data suggesting that inhibition of GSK3 by increasing serine phosphorylation is a response of GSK3 to psychotropics used in bipolar disorder, supporting the notion that GSK3 is a promising molecular target in the pharmacological treatment of bipolar disorder. © 2010 John Wiley and Sons A/S.

  5. Bipolar Disorder in Children (United States)


    Although bipolar disorder historically was thought to only occur rarely in children and adolescents, there has been a significant increase in children and adolescents who are receiving this diagnosis more recently (Carlson, 2005). Nonetheless, the applicability of the current bipolar disorder diagnostic criteria for children, particularly preschool children, remains unclear, even though much work has been focused on this area. As a result, more work needs to be done to further the understanding of bipolar symptoms in children. It is hoped that this paper can assist psychologists and other health service providers in gleaning a snapshot of the literature in this area so that they can gain an understanding of the diagnostic criteria and other behaviors that may be relevant and be informed about potential approaches for assessment and treatment with children who meet bipolar disorder criteria. First, the history of bipolar symptoms and current diagnostic criteria will be discussed. Next, assessment strategies that may prove helpful for identifying bipolar disorder will be discussed. Then, treatments that may have relevance to children and their families will be discussed. Finally, conclusions regarding work with children who may have a bipolar disorder diagnosis will be offered. PMID:24800202

  6. Investigations on the corrosion resistance of metallic bipolar plates (BPP) in proton exchange membrane fuel cells (PEMFC) - understanding the effects of material, coating and manufacturing (United States)

    Dur, Ender

    Polymer Electrolyte Membrane Fuel Cell (PEMFC) systems are promising technology for contributing to meet the deficiency of world`s clean and sustainable energy requirements in the near future. Metallic bipolar plate (BPP) as one of the most significant components of PEMFC device accounts for the largest part of the fuel cell`s stack. Corrosion for metallic bipolar plates is a critical issue, which influences the performance and durability of PEMFC. Corrosion causes adverse impacts on the PEMFC`s performance jeopardizing commercialization. This research is aimed at determining the corrosion resistance of metallic BPPs, particularly stainless steels, used in PEMFC from different aspects. Material selection, coating selection, manufacturing process development and cost considerations need to be addressed in terms of the corrosion behavior to justify the use of stainless steels as a BPP material in PEMFC and to make them commercially feasible in industrial applications. In this study, Ti, Ni, SS304, SS316L, and SS 430 blanks, and BPPs comprised of SS304 and SS316L were examined in terms of the corrosion behavior. SS316L plates were coated to investigate the effect of coatings on the corrosion resistance performance. Stamping and hydroforming as manufacturing processes, and three different coatings (TiN, CrN, ZrN) applied via the Physical Vapor Deposition (PVD) method in three different thicknesses were selected to observe the effects of manufacturing processes, coating types and coating thicknesses on the corrosion resistance of BPP, respectively. Uncoated-coated blank and formed BPP were subjected to two different corrosion tests: potentiostatic and potentiodynamic. Some of the substantial results: 1- Manufacturing processes have an adverse impact on the corrosion resistance. 2- Hydroformed plates have slightly higher corrosion resistance than stamped samples. 3- BPPs with higher channel size showed better corrosion resistance. 4- Since none of the uncoated samples

  7. Development of a portable PEM fuel cell system with bipolar plates consisting an electronically conductive thermoplastic Compound material; Entwicklung eines portablen PEM-Brennstoffzellensystems mit Bipolarplatten aus einem elektronisch leitfaehigen thermoplastischen Compound-Material

    Energy Technology Data Exchange (ETDEWEB)

    Niemzig, O.C.


    In order to meet the cost targets of PEM fuel cells for commercialization significant cost reductions of cell stack components like membrane/electrode assemblies and bipolar plates have become key aspects of research and development. Central topics of his work are the bipolar plates and humidification for portable applications. Best results concerning conductivity of an extensive screening of a variety of carbon polymer compounds with polypropylene as matrix could be achieved with the carbon black/graphite/polypropylene-base system. Successful tests of this material in a fuel cell stack could be performed as well as the proof of suitability concerning material- and manufacturing costs. Dependent on application a decrease of material cost to 2 Euro/kg to 1,8 Euro/kW seems to be possible. Finally bipolar plates consisting of a selected carbon polymer compound were successfully integrated and tested in a 20-cell stack which was implemented in a portable PEFC-demonstrator unit with a power output between 50 and 150 W. (orig.)

  8. Effect of dimensional error of metallic bipolar plate on the GDL pressure distribution in the PEM fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dong' an; Peng, Linfa; Lai, Xinmin [State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Dongchuan Road 800, Shanghai 200240 (China)


    Recently, the metallic bipolar plate (BPP) has received considerable attention because of its advantageous electrical and mechanical properties. In this study, a methodology based on FEA model and Monte Carlo simulation is developed to investigate the effect of dimensional error of the metallic BPP on the pressure distribution of gas diffusion layer (GDL). At first, a parameterized FEA model of metallic BPP/GDL assembly is established, and heights of the channel and rib are considered to be randomly varying parameters of normal distribution due to the dimensional error. Then, GDL pressure distributions with different dimensional errors are obtained respectively based on the Monte Carlo simulation, and the desirability function method is employed to evaluate them. At last, a regression equation between the GDL pressure distribution and the dimensional error is modeled. With the regression equation, the allowed maximum dimensional error for the metallic BPP is calculated. The methodology in this study can be applied to guide the design and manufacturing of the metallic BPP. (author)

  9. Bipolar nickel-hydrogen battery development - A program review (United States)

    Manzo, Michelle; Lenhart, Stephen; Hall, Arnold


    An overview of spacecraft power system design trends, focusing on higher power bus voltages and improved energy storage systems, is followed by a discussion of bipolar Ni/H2 battery development efforts. Several 10-cell batteries and one 50-cell battery are described, and performance results are presented. A comparison of individual-pressure-vessel and bipolar Ni/H2 technologies is used to suggest a new direction for bipolar Ni/H2 battery development efforts, toward a large number of passively cooled cells in parallel.

  10. The herpes virus Fc receptor gE-gI mediates antibody bipolar bridging to clear viral antigens from the cell surface.

    Directory of Open Access Journals (Sweden)

    Blaise Ndjamen


    Full Text Available The Herpes Simplex Virus 1 (HSV-1 glycoprotein gE-gI is a transmembrane Fc receptor found on the surface of infected cells and virions that binds human immunoglobulin G (hIgG. gE-gI can also participate in antibody bipolar bridging (ABB, a process by which the antigen-binding fragments (Fabs of the IgG bind a viral antigen while the Fc binds to gE-gI. IgG Fc binds gE-gI at basic, but not acidic, pH, suggesting that IgG bound at extracellular pH by cell surface gE-gI would dissociate and be degraded in acidic endosomes/lysosomes if endocytosed. The fate of viral antigens associated with gE-gI-bound IgG had been unknown: they could remain at the cell surface or be endocytosed with IgG. Here, we developed an in vitro model system for ABB and investigated the trafficking of ABB complexes using 4-D confocal fluorescence imaging of ABB complexes with transferrin or epidermal growth factor, well-characterized intracellular trafficking markers. Our data showed that cells expressing gE-gI and the viral antigen HSV-1 gD endocytosed anti-gD IgG and gD in a gE-gI-dependent process, resulting in lysosomal localization. These results suggest that gE-gI can mediate clearance of infected cell surfaces of anti-viral host IgG and viral antigens to evade IgG-mediated responses, representing a general mechanism for viral Fc receptors in immune evasion and viral pathogenesis.

  11. The problem of radiative depolarization in the 'Siberian Snake'

    International Nuclear Information System (INIS)

    Schwitters, R.


    As pointed out by Derbenev and Kondratenko and by the LEP Study Group, a 'Siberian Snake' may be a convenient method for providing longitudinally polarized beams at LEP. The author shows that at the highest LEP energies (approximately>60 GeV) synchrotron radiation with spin-flip may depolarize the beams. (Auth.)

  12. Depolarization temperature and piezoelectric properties of Na1/2 ...

    Indian Academy of Sciences (India)

    1/2Bi1/2(Zn1/3Nb2/3)O3, was synthesized using the two-stage calcination method and depolarization temperatures and piezoelectric properties were also investigated. The XRD analysis showed that the ceramics system had a morphotropic ...

  13. Depolarization temperature and piezoelectric properties of TiO3 ...

    Indian Academy of Sciences (India)


    2TiO3–Na1/2Bi1/2(Zn1/3Nb2/3)O3, was synthesized using the two-stage calcination method and depolarization temperatures and piezoelectric properties were also investigated. The XRD analysis showed that the ceramics system had a ...

  14. Twomey effect in subtropical stratocumulus clouds from UV depolarization lidar

    NARCIS (Netherlands)

    de Graaf, M.; Brown, Jessica; Donovan, D.P.; Nicolae, D.; Makoto, A.; Vassilis, A.; Balis, D.; Behrendt, A.; Comeron, A.; Gibert, F.; Landulfo, E.; McCormick, M.P.; Senff, C.; Veselovskii, I.; Wandinger, U.


    Marine stratocumulus clouds are important climate regulators, reflecting sunlight over a dark ocean background. A UV-depolarization lidar on Ascension, a small remote island in the south Atlantic, measured cloud droplet sizes and number concentration using an inversion method based on Monte Carlo

  15. A 37.5-kW point design comparison of the nickel-cadmium battery, bipolar nickel-hydrogen battery, and regenerative hydrogen-oxygen fuel cell energy storage subsystems for low earth orbit

    International Nuclear Information System (INIS)

    Manzo, M.A.; Hoberecht, M.A.


    Nickel-cadmium batteries, bipolar nickel-hydrogen batteries, and regenerative fuel cell storage subsystems were evaluated for use as the storage subsystem in a 37.5 kW power system for space station. Design requirements were set in order to establish a common baseline for comparison purposes. The storage subsystems were compared on the basis of effective energy density, round trip electrical efficiency, total subsystem weight and volume, and life

  16. A 37.5-kW point design comparison of the nickel-cadmium battery, bipolar nickel-hydrogen battery, and regenerative hydrogen-oxygen fuel cell energy storage subsystems for low earth orbit (United States)

    Manzo, M. A.; Hoberecht, M. A.


    Nickel-cadmium batteries, bipolar nickel-hydrogen batteries, and regenerative fuel cell storage subsystems were evaluated for use as the storage subsystem in a 37.5 kW power system for Space Station. Design requirements were set in order to establish a common baseline for comparison purposes. The storage subsystems were compared on the basis of effective energy density, round trip electrical efficiency, total subsystem weight and volume, and life.

  17. What is Bipolar Disorder? (United States)

    ... down” Have trouble sleeping Think about death or suicide Can someone have bipolar disorder along with other problems? Yes. Sometimes people having very strong mood episodes may have psychotic symptoms. Psychosis affects thoughts ...

  18. Activation of cathepsin L contributes to the irreversible depolarization induced by oxygen and glucose deprivation in rat hippocampal CA1 neurons. (United States)

    Kikuta, Shogo; Murai, Yoshinaka; Tanaka, Eiichiro


    Oxygen and glucose deprivation (OGD) elicits a rapid and irreversible depolarization with a latency of ∼5min in intracellular recordings of hippocampal CA1 neurons in rat slice preparations. In the present study, we examined the role of cathepsin L in the OGD-induced depolarization. OGD-induced depolarizations were irreversible as no recovery of membrane potential was observed. The membrane potential reached 0mV when oxygen and glucose were reintroduced immediately after the onset of the OGD-induced rapid depolarization. The OGD-induced depolarizations became reversible when the slice preparations were pre-incubated with cathepsin L inhibitors (types I and IV at 0.3-2nM and 0.3-30nM, respectively). Moreover, pre-incubation with these cathepsin inhibitors prevented the morphological changes, including swelling of the cell soma and fragmentation of dendrites, observed in control neurons after OGD. These findings suggest that the activation of cathepsin L contributes to the irreversible depolarization produced by OGD. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Mitochondrial depolarization in yeast zygotes inhibits clonal expansion of selfish mtDNA. (United States)

    Karavaeva, Iuliia E; Golyshev, Sergey A; Smirnova, Ekaterina A; Sokolov, Svyatoslav S; Severin, Fedor F; Knorre, Dmitry A


    Non-identical copies of mitochondrial DNA (mtDNA) compete with each other within a cell and the ultimate variant of mtDNA present depends on their relative replication rates. Using yeast Saccharomyces cerevisiae cells as a model, we studied the effects of mitochondrial inhibitors on the competition between wild-type mtDNA and mutant selfish mtDNA in heteroplasmic zygotes. We found that decreasing mitochondrial transmembrane potential by adding uncouplers or valinomycin changes the competition outcomes in favor of the wild-type mtDNA. This effect was significantly lower in cells with disrupted mitochondria fission or repression of the autophagy-related genes ATG8 , ATG32 or ATG33 , implying that heteroplasmic zygotes activate mitochondrial degradation in response to the depolarization. Moreover, the rate of mitochondrially targeted GFP turnover was higher in zygotes treated with uncoupler than in haploid cells or untreated zygotes. Finally, we showed that vacuoles of zygotes with uncoupler-activated autophagy contained DNA. Taken together, our data demonstrate that mitochondrial depolarization inhibits clonal expansion of selfish mtDNA and this effect depends on mitochondrial fission and autophagy. These observations suggest an activation of mitochondria quality control mechanisms in heteroplasmic yeast zygotes. © 2017. Published by The Company of Biologists Ltd.

  20. Slow Bursting Neurons of Mouse Cortical Layer 6b Are Depolarized by Hypocretin/Orexin and Major Transmitters of Arousal. (United States)

    Wenger Combremont, Anne-Laure; Bayer, Laurence; Dupré, Anouk; Mühlethaler, Michel; Serafin, Mauro


    Neurons firing spontaneously in bursts in the absence of synaptic transmission have been previously recorded in different layers of cortical brain slices. It has been suggested that such neurons could contribute to the generation of alternating UP and DOWN states, a pattern of activity seen during slow-wave sleep. Here, we show that in layer 6b (L6b), known from our previous studies to contain neurons highly responsive to the wake-promoting transmitter hypocretin/orexin (hcrt/orx), there is a set of neurons, endowed with distinct intrinsic properties, which displayed a strong propensity to fire spontaneously in rhythmic bursts. In response to small depolarizing steps, they responded with a delayed firing of action potentials which, upon higher depolarizing steps, invariably inactivated and were followed by a depolarized plateau potential and a depolarizing afterpotential. These cells also displayed a strong hyperpolarization-activated rectification compatible with the presence of an I h current. Most L6b neurons with such properties were able to fire spontaneously in bursts. Their bursting activity was of intrinsic origin as it persisted not only in presence of blockers of ionotropic glutamatergic and GABAergic receptors but also in a condition of complete synaptic blockade. However, a small number of these neurons displayed a mix of intrinsic bursting and synaptically driven recurrent UP and DOWN states. Most of the bursting L6b neurons were depolarized and excited by hcrt/orx through a direct postsynaptic mechanism that led to tonic firing and eventually inactivation. Similarly, they were directly excited by noradrenaline, histamine, dopamine, and neurotensin. Finally, the intracellular injection of these cells with dye and their subsequent Neurolucida reconstruction indicated that they were spiny non-pyramidal neurons. These results lead us to suggest that the propensity for slow rhythmic bursting of this set of L6b neurons could be directly impeded by hcrt

  1. Nickel hydrogen bipolar battery electrode design (United States)

    Puglisi, V. J.; Russell, P.; Verrier, D.; Hall, A.


    The preferred approach of the NASA development effort in nickel hydrogen battery design utilizes a bipolar plate stacking arrangement to obtain the required voltage-capacity configuration. In a bipolar stack, component designs must take into account not only the typical design considerations such as voltage, capacity and gas management, but also conductivity to the bipolar (i.e., intercell) plate. The nickel and hydrogen electrode development specifically relevant to bipolar cell operation is discussed. Nickel oxide electrodes, having variable type grids and in thicknesses up to .085 inch are being fabricated and characterized to provide a data base. A selection will be made based upon a system level tradeoff. Negative (hydrpogen) electrodes are being screened to select a high performance electrode which can function as a bipolar electrode. Present nickel hydrogen negative electrodes are not capable of conducting current through their cross-section. An electrode was tested which exhibits low charge and discharge polarization voltages and at the same time is conductive. Test data is presented.

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

    NARCIS (Netherlands)

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

    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

  3. Surface characteristic of chemically converted graphene coated low carbon steel by electro spray coating method for polymer electrolyte membrane fuel cell bipolar plate. (United States)

    Kim, Jungsoo; Kim, Yang Do; Nam, Dae Geun


    Graphene was coated on low carbon steel (SS400) by electro spray coating method to improve its properties of corrosion resistance and contact resistance. Exfoliated graphite was made of the graphite by chemical treatment (Chemically Converted Graphene, CCG). CCG is distributed using dispersing agent, and low carbon steel was coated with diffuse graphene solution by electro spray coating method. The structure of the CCG was analyzed using XRD and the coating layer of surface was analyzed using SEM. Analysis showed that multi-layered graphite structure was destroyed and it was transformed in to fine layers graphene structure. And the result of SEM analysis on the surface and the cross section, graphene layer was uniformly formed with 3-5 microm thickness on the surface of substrate. Corrosion resistance test was applied in the corrosive solution which is similar to the polymer electrolyte membrane fuel cell (PEMFC) stack inside. And interfacial contact resistance (ICR) test was measured to simulate the internal operating conditions of PEMFC stack. As a result of measuring corrosion resistance and contact resistance, it could be confirmed that low carbon steel coated with CCG was revealed to be more effective in terms of its applicability as PEMFC bipolar plate.

  4. Investigation of the effects of process sequence on the contact resistance characteristics of coated metallic bipolar plates for polymer electrolyte membrane fuel cells (United States)

    Turan, Cabir; Cora, Ömer Necati; Koç, Muammer


    In this study, results of an investigation on the effects of manufacturing and coating process sequence on the contact resistance (ICR) of metallic bipolar plates (BPP) for polymer electrolyte membrane fuel cells (PEMFCs) are presented. Firstly, uncoated stainless steel 316L blanks were formed into BPP through hydroforming and stamping processes. Then, these formed BPP samples were coated with three different PVD coatings (CrN, TiN and ZrN) at three different thicknesses (0.1, 0.5 and 1 μm). Secondly, blanks of the same alloy were coated first with the same coatings, thickness and technique; then, they were formed into BPPs of the same shape and dimensions using the manufacturing methods as in the first group. Finally, these two groups of BPP samples were tested for their ICR to reveal the effect of process sequence. ICR tests were also conducted on the BPP plates both before and after exposure to corrosion to disclose the effect of corrosion on ICR. Coated-then-formed BPP samples exhibited similar or even better ICR performance than formed-then-coated BPP samples. Thus, manufacturing of coated blanks can be concluded to be more favorable and worth further investigation in quest of making cost effective BPPs for mass production of PEMFC.

  5. Conductive materials for proton exchange membrane fuel cell bipolar plates made from PVDF, PET and co-continuous PVDF/PET filled with carbon additives

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, L.; Mighri, F.; Deyrail, Y. [CREPEC, Center for Applied Research on Polymers and Composites, QC (Canada); Department of Chemical Engineering, Laval University, QC (Canada); Elkoun, S. [CREPEC, Center for Applied Research on Polymers and Composites, QC (Canada); Department of Mechanical Engineering, Sherbrooke University, QC (Canada)


    The aim of this work was to develop and characterise electrically conductive materials for proton exchange membrane fuel cells and bipolar plates (BPPs). These BPPs were made from highly conductive blends of polyethylene terephthalate (PET) and polyvinylidene fluoride (PVDF), as matrix phase. The conductive materials were developed from carefully formulated blends composed of conductive carbon black (CB) powder and, in some cases, graphite synthetic flakes mixed with pure PET, PVDF or with PVDF/PET systems. They were first developed by twin-screw extrusion process then compression-molded to give BPP final shape. As the developed blends have to meet properties suitable for BPP applications, they were characterised for their rheological properties, electrical through-plane resistivity (the inverse of conductivity), oxygen permeability, flexural and impact properties. Results showed that lower resistivity was obtained with PVDF/CB blends due to the higher interfacial energy between the PVDF matrix and CB and also the higher density and crystallinity of PVDF, compared to those of PET. It was also observed that the lowest resistivity values were obtained with mixing PVDF and PET at controlled compositions to ensure PVDF/PET co-continuous morphology. Also, slow cooling rates helped to attain the lowest values of through-plane resistivity for all studied blends. This behaviour was related to the higher crystallinity obtained with low cooling rates leading to smaller amorphous regions in which carbon particles are much more concentrated. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Depolarization-mediated regulation of alternative splicing

    Directory of Open Access Journals (Sweden)

    Alok eSharma


    Full Text Available Alternative splicing in eukaryotes plays an important role in regulating gene expression by selectively including alternative exons. A wealth of information has been accumulated that explains how alternative exons are selected in a developmental stage- or tissue-specific fashion. However, our knowledge of how cells respond to environmental changes to alter alternative splicing is very limited. For example, although a number of alternative exons have been shown to be regulated by calcium level alterations, the underlying mechanisms are not well understood. As calcium signaling in neurons plays a crucial role in essential neuronal functions such as learning and memory formation, it is important to understand how this process is regulated at every level in gene expression. The significance of the dynamic control of alternative splicing in response to changes of calcium levels has been largely unappreciated. In this communication, we will summarize the recent advances in calcium signaling-mediated alternative splicing that have provided some insights into the important regulatory mechanisms. In addition to describing the cis-acting RNA elements on the pre-mRNA molecules that respond to changes of intracellular calcium levels, we will summarize how splicing regulators change and affect alternative splicing in this process. We will also discuss a novel mode of calcium-mediated splicing regulation at the level of chromatin structure and transcription.

  7. Nanosecond bipolar pulse generators for bioelectrics. (United States)

    Xiao, Shu; Zhou, Chunrong; Yang, Enbo; Rajulapati, Sambasiva R


    Biological effects caused by a nanosecond pulse, such as cell membrane permeabilization, peripheral nerve excitation and cell blebbing, can be reduced or cancelled by applying another pulse of reversed polarity. Depending on the degree of cancellation, the pulse interval of these two pulses can be as long as dozens of microseconds. The cancellation effect diminishes as the pulse duration increases. To study the cancellation effect and potentially utilize it in electrotherapy, nanosecond bipolar pulse generators must be made available. An overview of the generators is given in this paper. A pulse forming line (PFL) that is matched at one end and shorted at the other end allows a bipolar pulse to be produced, but no delay can be inserted between the phases. Another generator employs a combination of a resistor, an inductor and a capacitor to form an RLC resonant circuit so that a bipolar pulse with a decaying magnitude can be generated. A third generator is a converter, which converts an existing unipolar pulse to a bipolar pulse. This is done by inserting an inductor in a transmission line. The first phase of the bipolar pulse is provided by the unipolar pulse's rising phase. The second phase is formed during the fall time of the unipolar pulse, when the inductor, which was previously charged during the flat part of the unipolar pulse, discharges its current to the load. The fourth type of generator uses multiple MOSFET switches stacked to turn on a pre-charged, bipolar RC network. This approach is the most flexible in that it can generate multiphasic pulses that have different amplitudes, delays, and durations. However, it may not be suitable for producing short nanosecond pulses (<100 ns), whereas the PFL approach and the RLC approach with gas switches are used for this range. Thus, each generator has its own advantages and applicable range. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Depolarized inactivation overcomes impaired activation to produce DRG neuron hyperexcitability in a Nav1.7 mutation in a patient with distal limb pain. (United States)

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


    Sodium channel Nav1.7, encoded by SCN9A, is expressed in DRG neurons and regulates their excitability. Genetic and functional studies have established a critical contribution of Nav1.7 to human pain disorders. We have now characterized a novel Nav1.7 mutation (R1279P) from a female human subject with distal limb pain, in which depolarized fast inactivation overrides impaired activation to produce hyperexcitability and spontaneous firing in DRG neurons. Whole-cell voltage-clamp recordings in human embryonic kidney (HEK) 293 cells demonstrated that R1279P significantly depolarizes steady-state fast-, slow-, and closed-state inactivation. It accelerates deactivation, decelerates inactivation, and facilitates repriming. The mutation increases ramp currents in response to slow depolarizations. Our voltage-clamp analysis showed that R1279P depolarizes channel activation, a change that was supported by our multistate structural modeling. Because this mutation confers both gain-of-function and loss-of-function attributes on the Nav1.7 channel, we tested the impact of R1279P expression on DRG neuron excitability. Current-clamp studies reveal that R1279P depolarizes resting membrane potential, decreases current threshold, and increases firing frequency of evoked action potentials within small DRG neurons. The populations of spontaneously firing and repetitively firing neurons were increased by expressing R1279P. These observations indicate that the dominant proexcitatory gating changes associated with this mutation, including depolarized steady-state fast-, slow-, and closed-state inactivation, faster repriming, and larger ramp currents, override the depolarizing shift of activation, to produce hyperexcitability and spontaneous firing of nociceptive neurons that underlie pain. Copyright © 2014 the authors 0270-6474/14/3412328-13$15.00/0.

  9. Bipolar Affective Disorder and Migraine

    Directory of Open Access Journals (Sweden)

    Birk Engmann


    Full Text Available This paper consists of a case history and an overview of the relationship, aetiology, and treatment of comorbid bipolar disorder migraine patients. A MEDLINE literature search was used. Terms for the search were bipolar disorder bipolar depression, mania, migraine, mood stabilizer. Bipolar disorder and migraine cooccur at a relatively high rate. Bipolar II patients seem to have a higher risk of comorbid migraine than bipolar I patients have. The literature on the common roots of migraine and bipolar disorder, including both genetic and neuropathological approaches, is broadly discussed. Moreover, bipolar disorder and migraine are often combined with a variety of other affective disorders, and, furthermore, behavioural factors also play a role in the origin and course of the diseases. Approach to treatment options is also difficult. Several papers point out possible remedies, for example, valproate, topiramate, which acts on both diseases, but no first-choice treatments have been agreed upon yet.

  10. Depression and Bipolar Support Alliance (United States)

    Depression and Bipolar Support Alliance Crisis Hotline Information Coping with a Crisis Suicide Prevention Information Psychiatric Hospitalization ... sign-up Education info, training, events Mood Disorders Depression Bipolar Disorder Anxiety Screening Center Co-occurring Illnesses/ ...

  11. Spreading depolarizations occur in human ischemic stroke with high incidence

    DEFF Research Database (Denmark)

    Dohmen, C.; Sakowitz, O.W.; Fabricius, M.


    Objective: Cortical spreading depression (CSD) and periinfarct depolarization (PID) have been shown in various experimental models of stroke to cause secondary neuronal damage and infarct expansion. For decades it has been questioned whether CSD or PID occur in human ischemic stroke. Here, we...... potential change spreading between adjacent channels was accompanied by transient depression of ECoG activity. In PID, a slow potential change spread between neighboring channels despite already established suppression of ECoG activity. Most CSDs and PIDs appeared repetitively in clusters. CSD or PID...... was observed in all but two patients. In these two patients, the electrode strip had been placed over infarcted tissue, and accordingly, no local ECoG or recurrent transient depolarization activity occurred throughout the observation period. Interpretation: CSD and PID occurred spontaneously with high...

  12. Linear theory of beam depolarization due to vertical betatron motion

    International Nuclear Information System (INIS)

    Chao, A.W.; Schwitters, R.F.


    It is well known that vertical betatron motion in the presence of quantum fluctuations leads to some degree of depolarization of a transversely polarized beam in electron-positron storage rings even for energies away from spin resonances. Analytic formulations of this problem, which require the use of simplifying assumptions, generally have shown that there exist operating energies where typical storage rings should exhibit significant beam polarization. Due to the importance of beam polarization in many experiments, we present here a complete calculation of the depolarization rate to lowest order in the perturbing fields, which are taken to be linear functions of the betatron motion about the equilibrium orbit. The results are applicable to most high energy storage rings. Explicit calculations are given for SPEAR and PEP. 7 refs., 8 figs

  13. Bipolar Plasma Membrane Distribution of Phosphoinositides and Their Requirement for Auxin-Mediated Cell Polarity and Patterning in Arabidopsis

    NARCIS (Netherlands)

    Tejos, R.; Sauer, M.; Vanneste, S.; Palacios-Gomez, M.; Li, H.; Heilmann, M.; van Wijk, R.; Vermeer, J.E.M.; Heilmann, I.; Munnik, T.; Friml, J.


    Cell polarity manifested by asymmetric distribution of cargoes, such as receptors and transporters, within the plasma membrane (PM) is crucial for essential functions in multicellular organisms. In plants, cell polarity (re)establishment is intimately linked to patterning processes. Despite the

  14. Piezoelectric effect in polarized and electrically depolarized ferrotextures

    International Nuclear Information System (INIS)

    Luchaninov, A.G.; Shil'nikov, A.V.; Shuvalov, L.A.


    Piezoelectric moduli were calculated for ferroelectric textures in the states with the greatest possible (in terms of symmetry) polarization and the zero polarization (obtained from the former by electrical depolarization). The calculations were performed for the textures of crystals of the classes 2, 3, 4, 6, mm2, 3m, 4mm,and 6mm. The experimental results for lead zirconate-titanate- and barium-titanate-based piezoelectric ceramic are reported

  15. Beam-beam depolarization in SPEAR and PEP

    International Nuclear Information System (INIS)

    Montague, B.W.


    In this note some approximate estimates are made of depolarization due to beam-beam forces in SPEAR and PEP, using the results of a calculation by Kondratenko. The model assumes head-on collisions between bunches of Gaussian distribution in the transverse directions; the force on the weak-beam particle is taken to be a δ-function at the interaction point. 1 ref

  16. Scattering and depolarization of polarized neutrons in ferrofluids

    International Nuclear Information System (INIS)

    Balasoiu, M.; Dokukin, E.B.; Kozhevnikov, S.V.; Nikitenko, Y.V.


    On the SPN - 1 polarized neutron spectrometer at IBR -2 high - flux pulsed rector there were carried out preliminary measurements on transmission and polarization of a neutron beam passing through a magnetic colloidal system of Fe 3 O 4 particles in transformer oil and dodecane carriers. It was found that in the ferrofluids with magnetite particles exist, dependent on the particle volume concentration and the magnitude of the external magnetic field, effects of depolarization and nuclear - magnetic small angle scattering. (author)

  17. On the polarization and depolarization of the electromagnetic waves

    International Nuclear Information System (INIS)

    Borghese, Ferdinando; Denti, Paolo; Saija, Rosalba; Cecchi-Pestellini, Cesare


    We discuss a general description of the polarization of monochromatic electromagnetic waves that proves useful when the customary description in terms of Stokes parameters does not apply. We also show how this description can be exploited to study the depolarization of linearly polarized waves in the interior of porous model cosmic dust grains. The results that we discuss may affect our understanding of several problems that are relevant for astrobiology

  18. Atrioventricular depolarization differences identify coronary artery anomalies in Kawasaki disease. (United States)

    Cortez, Daniel; Sharma, Nandita; Jone, Pei-Ni


    Kawasaki disease (KD) is the leading cause of acquired heart disease in children. Signal average electrocardiogram changes in patients during the acute phase of KD with coronary artery anomalies (CAA) include depolarization changes. We set out to determine if 12-lead-derived atrioventricular depolarization differences can identify CAA in patients with KD. A blinded, retrospective case-control study of patients with KD was performed. Deep Q waves, corrected QT-intervals (QTc), spatial QRS-T angles, T-wave vector magnitudes (RMS-T), and a novel parameter for assessment of atrioventricular depolarization difference (the spatial PR angle) and a two dimensional PR angle were assessed. Comparisons between groups were performed to test for significant differences. One hundred one patients with KD were evaluated, with 68 having CAA (67.3%, mean age 3.6 ± 3.0 years, 82.6% male), and 32 without CAA (31.7%, mean age 2.7 ± 3.2 years, 70.4% male). The spatial PR angle significantly discriminated KD patients with CAA from those without, 59.7° ± 31.1° versus 41.6° ± 11.5° (p differences, measured by the spatial or two dimensional PR angle differentiate KD patients with CAA versus those without. © 2016 Wiley Periodicals, Inc.

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

    Energy Technology Data Exchange (ETDEWEB)

    Boutin, Claude, E-mail: [Ecole Nationale des Travaux Publics de l' Etat, Université de Lyon, LGCB, UMR CNRS 5513, Vaulx-en-Velin (France); Schwan, Logan [Acoustics Research Center, University of Salford, Newton Building, Salford M5 4WT (United Kingdom); Dietz, Matthew S. [Department of Civil Engineering, University of Bristol, Queen' s Building, Bristol BS8 1TR (United Kingdom)


    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.

  20. Depolarization-stimulated 42K+ efflux in rat aorta is calcium- and cellular volume-dependent

    International Nuclear Information System (INIS)

    Magliola, L.; Jones, A.W.


    The purpose of this study was to investigate the factors controlling membrane permeability to potassium of smooth muscle cells from rat aorta stimulated by depolarization. The increase 42 K+ efflux (change in the rate constant) induced by depolarization (application of high concentrations of potassium chloride) was inhibited significantly by the calcium antagonists diltiazem and nisoldipine. Parallel inhibitory effects on contraction were observed. Diltiazem also inhibited potassium-stimulated 36 Cl- efflux. The addition of 25-150 mM KCl to normal physiologic solution stimulated 42 K+ efflux in a concentration-dependent manner. Diltiazem suppressed potassium-stimulated 42 K+ efflux approximately 90% at 25 mM KCl and approximately 40% at 150 mM KCl. The ability of nisoldipine to inhibit 42 K+ efflux also diminished as the potassium chloride concentration was elevated. The component of efflux that was resistant to calcium antagonists probably resulted from a decrease in the electrochemical gradient for potassium. Cellular water did not change during potassium addition. Substitution of 80 and 150 mM KCl for sodium chloride produced cellular swelling and enhanced potassium-stimulated 42 K+ efflux compared with potassium chloride addition. The addition of sucrose to prevent cellular swelling reduced efflux response to potassium substitution toward that of potassium addition. A hypoosmolar physiologic solution produced an increase in the 42 K+ efflux and a contracture that were both prevented by the addition of sucrose. We concluded that the depolarization-mediated 42 K+ efflux has three components: one is calcium dependent; a second is dependent on cellular volume; and a third is resistant to inhibition by calcium antagonists

  1. Influence of thermal reduced depolarization on a repetition-frequency laser amplifier and compensation

    Institute of Scientific and Technical Information of China (English)

    Xin-ying Jiang; Xiong-wei Yan; Zhen-guo Wang; Jian-gang Zheng; Ming-zhong Li; Jing-qin Su


    Thermal stress can induce birefringence in a laser medium, which can cause depolarization of the laser. The depolarization effect will be very severe in a high-average-power laser. Because the depolarization will make the frequency doubling efficiency decline, it should be compensated. In this paper, the thermal characteristics of two kinds of materials are analyzed in respect of temperature, thermal deformation and thermal stress. The depolarization result from thermal stress was simulated. Depolarization on non-uniform pumping was also simulated, and the compensation method is discussed.

  2. Energy and Beam-Offset dependence of the Luminosity weighted depolarization for CLIC

    CERN Document Server

    Esberg, Jakob; Uggerhoj, Ulrik; Dalena, Barbara


    We report on simulations of e+e- depolarization due to beam-beam effects. These effects are studied for CLIC at 3 TeV, using GUINEA PIG++. We find a strong energy dependence of the luminosity weighted depolarization. In the luminosity peak at CLIC the total luminosity weighted depolarization remains below the one per-mil level. The effect of a vertical offset on the energy dependent depolarization is investigated. The depolarization in the luminosity peak remains below per-cent level even for 5sy offsets.

  3. Bipolar zinc/oxygen battery development

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, S [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Schlatter, C [Swiss Federal Inst. of Technology, Lausanne (Switzerland)


    A bipolar electrically rechargeable Zn/O{sub 2} battery has been developed. Reticulated copper foam served as substrate for the zinc deposit on the anodic side, and La{sub 0.6}Ca{sub 0.4}CoO{sub 3}-catalyzed bifunctional oxygen electrodes were used on the cathodic side of the cells. The 100 cm{sup 2} unit cell had an open circuit voltage of 1,4 V(O{sub 2}) in moderately alkaline electrolyte. The open circuit voltage and the peak power measured for a stack containing seven cells were ca. 10V and 90W, respectively. The current-potential behaviour was determined as a function of the number of bipolar cells, and the maximum discharge capacity was determined at different discharge rates. (author) 4 figs., 1 ref.

  4. An investigation of coated aluminium bipolar plates for PEMFC

    International Nuclear Information System (INIS)

    Lin, Chien-Hung; Tsai, Sung-Ying


    Highlights: ► Coated aluminium bipolar plates demonstrate the hydrophobic property than the raw material. ► The corrosion behaviour of bipolar plate decreases the PEMFC performance severely. ► These PEMFCs are measured by current–voltage (I–V) curve test. ► The oxide film increases the interfacial contact resistance. -- Abstract: The performance of Al-alloy bipolar plates for the PEMFC (proton exchange membrane fuel cell) system is investigated in this paper. The metallic bipolar plates are modified with a Ni–P coating. The performance of the Al-alloy bipolar plates is evaluated by the coating structure, corrosion resistance, contact angle and single cell performance. The results indicate that the coated aluminium bipolar plates demonstrate hydrophobic and anti-corrosive properties. The hydrophobic property increases the contact angle on the surface from 46.08° to 80.51°. Meanwhile, the corrosion rate of the Ni–P coating can be over 1 order of magnitude lower than that of the substrate. Hence, the substrate with the coating maintains superior performance under the long term test. The present study proves that both the hydrophobicity and corrosion resistance significantly affect the metallic bipolar plate.

  5. Rat hypocretin/orexin neurons are maintained in a depolarized state by TRPC channels.

    Directory of Open Access Journals (Sweden)

    Vesna Cvetkovic-Lopes

    Full Text Available In a previous study we proposed that the depolarized state of the wake-promoting hypocretin/orexin (hcrt/orx neurons was independent of synaptic inputs as it persisted in tetrodotoxin and low calcium/high magnesium solutions. Here we show first that these cells are hyperpolarized when external sodium is lowered, suggesting that non-selective cation channels (NSCCs could be involved. As canonical transient receptor channels (TRPCs are known to form NSCCs, we looked for TRPCs subunits using single-cell RT-PCR and found that TRPC6 mRNA was detectable in a small minority, TRPC1, TRPC3 and TRPC7 in a majority and TRPC4 and 5 in the vast majority (∼90% of hcrt/orx neurons. Using intracellular applications of TRPC antibodies against subunits known to form NSCCs, we then found that only TRPC5 antibodies elicited an outward current, together with hyperpolarization and inhibition of the cells. These effects were blocked by co-application of a TRPC5 antigen peptide. Voltage-clamp ramps in the presence or absence of TRPC5 antibodies indicated the presence of a current with a reversal potential close to -15 mV. Application of the non-selective TRPC channel blocker, flufenamic acid, had a similar effect, which could be occluded in cells pre-loaded with TRPC5 antibodies. Finally, using the same TRPC5 antibodies we found that most hcrt/orx cells show immunostaining for the TRPC5 subunit. These results suggest that hcrt/orx neurons are endowed with a constitutively active non-selective cation current which depends on TRPC channels containing the TRPC5 subunit and which is responsible for the depolarized and active state of these cells.

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

    Directory of Open Access Journals (Sweden)

    Marion SB


    Full Text Available Sarah B Marion, Allen W MangelRTI Health Solutions, Research Triangle Park, NC, USAAbstract: 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

  7. Defective neuronal migration and inhibition of bipolar to multipolar transition of migrating neural cells by Mesoderm-Specific Transcript, Mest, in the developing mouse neocortex. (United States)

    Ji, Liting; Bishayee, Kausik; Sadra, Ali; Choi, Seunghyuk; Choi, Wooyul; Moon, Sungho; Jho, Eek-Hoon; Huh, Sung-Oh


    Brain developmental disorders such as lissencephaly can result from faulty neuronal migration and differentiation during the formation of the mammalian neocortex. The cerebral cortex is a modular structure, where developmentally, newborn neurons are generated as a neuro-epithelial sheet and subsequently differentiate, migrate and organize into their final positions in the cerebral cortical plate via a process involving both tangential and radial migration. The specific role of Mest, an imprinted gene, in neuronal migration has not been previously studied. In this work, we reduced expression of Mest with in utero electroporation of neuronal progenitors in the developing embryonic mouse neocortex. Reduction of Mest levels by shRNA significantly reduced the number of neurons migrating to the cortical plate. Also, Mest-knockdown disrupted the transition of bipolar neurons into multipolar neurons migrating out of the sub-ventricular zone region. The migrating neurons also adopted a more tangential migration pattern upon knockdown of the Mest message, losing their potential to attach to radial glia cells, required for radial migration. The differentiation and migration properties of neurons via Wnt-Akt signaling were affected by Mest changes. In addition, miR-335, encoded in a Mest gene intron, was identified as being responsible for blocking the default tangential migration of the neurons. Our results suggest that Mest and its intron product, miR-335, play important roles in neuronal migration with Mest regulating the morphological transition of primary neurons required in the formation of the mammalian neocortex. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  8. A mechanical-electrical finite element method model for predicting contact resistance between bipolar plate and gas diffusion layer in PEM fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Xinmin; Liu, Dong' an; Peng, Linfa [State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Ni, Jun [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109-2125 (United States)


    Contact resistance between the bipolar plate (BPP) and the gas diffusion layer (GDL) plays a significant role on the power loss in a proton exchange membrane (PEM) fuel cell. There are two types of contact behavior at the interface of the BPP and GDL, which are the mechanical one and the electrical one. Furthermore, the electrical contact behavior is dependent on the mechanical one. Thus, prediction of the contact resistance is a coupled mechanical-electrical problem. The current FEM models for contact resistance estimation can only simulate the mechanical contact behavior and moreover they are based on the assumption that the contact surface is equipotential, which is not the case in a real BPP/GDL assembly due to the round corner and margin of the BPP. In this study, a mechanical-electrical FEM model was developed to predict the contact resistance between the BPP and GDL based on the experimental interfacial contact resistivity. At first, the interfacial contact resistivity was obtained by experimentally measuring the contact resistance between the GDL and a flat graphite plate of the same material and processing conditions as the BPP. Then, with the interfacial contact resistivity, the mechanical and electrical contact behaviors were defined and the potential distribution of the BPP/GDL assembly was analyzed using the mechanical-electrical FEM model. At last, the contact resistance was calculated according to the potential drop and the current of the contact surface. The numerical results were validated by comparing with those of the model reported previously. The influence of the round corner of the BPP on the contact resistance was also studied and it is found that there exists an optimal round corner that can minimize the contact resistance. This model is beneficial in understanding the mechanical and electrical contact behaviors between the BPP and GDL, and can be used to predict the contact resistance in a new BPP/GDL assembly. (author)

  9. Investigations on the micro-scale surface interactions at the tool and workpiece interface in micro-manufacturing of bipolar plates for proton exchange membrane fuel cells (United States)

    Peker, Mevlut Fatih

    Micro-forming studies have been more attractive in recent years because of miniaturization trend. One of the promising metal forming processes, micro-stamping, provides durability, strength, surface finish, and low cost for metal products. Hence, it is considered a prominent method for fabricating bipolar plates (BPP) with micro-channel arrays on large metallic surfaces to be used in Proton Exchange Membrane Fuel Cells (PEMFC). Major concerns in micro-stamping of high volume BPPs are surface interactions between micro-stamping dies and blank metal plates, and tribological changes. These concerns play a critical role in determining the surface quality, channel formation, and dimensional precision of bipolar plates. The surface quality of BPP is highly dependent on the micro-stamping die surface, and process conditions due to large ratios of surface area to volume (size effect) that cause an increased level of friction and wear issues at the contact interface. Due to the high volume and fast production rates, BPP surface characteristics such as surface roughness, hardness, and stiffness may change because of repeated interactions between tool (micro-forming die) and workpiece (sheet blank of interest). Since the surface characteristics of BPPs have a strong effect on corrosion and contact resistance of bipolar plates, and consequently overall fuel cell performance, evolution of surface characteristics at the tool and workpiece should be monitored, controlled, and kept in acceptable ranges throughout the long production cycles to maintain the surface quality. Compared to macro-forming operations, tribological changes in micro-forming process are bigger challenges due to their dominance and criticality. Therefore, tribological size effect should be considered for better understanding of tribological changes in micro-scale. The integrity of process simulation to the experiments, on the other hand, is essential. This study describes an approach that aims to investigate

  10. Reduced mRNA expression of PTGDS in peripheral blood mononuclear cells of rapid-cycling bipolar disorder patients compared with healthy control subjects

    DEFF Research Database (Denmark)

    Munkholm, Klaus; Peijs, Lone; Kessing, Lars Vedel


    was measured in 37 rapid-cycling bipolar disorder patients and 40 age- and gender-matched healthy control subjects using reverse transcription quantitative real-time polymerase chain reaction. Repeated measurements of PTGDS and AKR1C3 mRNA expression were obtained in various affective states during 6-12 months...... and compared with repeated measurements in healthy control subjects. RESULTS: Adjusted for age and gender, PTGDS mRNA expression was down-regulated in rapid-cycling bipolar disorder patients in a euthymic, depressive, and manic/hypomanic state compared with healthy control subjects. No difference in PTGDS m...

  11. Types of Bipolar Disorder (United States)

    ... Events Home Science News Meetings and Events Multimedia Social Media Press Resources Newsletters NIMH News Feeds About Us ... has a lot of money, or has special powers. Someone having psychotic symptoms ... Substance Abuse: People with bipolar disorder may also misuse alcohol ...

  12. Discrete bipolar universal integrals

    Czech Academy of Sciences Publication Activity Database

    Greco, S.; Mesiar, Radko; Rindone, F.


    Roč. 252, č. 1 (2014), s. 55-65 ISSN 0165-0114 R&D Projects: GA ČR GAP402/11/0378 Institutional support: RVO:67985556 Keywords : bipolar integral * universal integral * Choquet integral Subject RIV: BA - General Mathematics Impact factor: 1.986, year: 2014

  13. El trastorno bipolar


    Freaza Rodríguez, Paula


    Se exponen los aspectos más relevantes del trastorno bipolar, entender qué significa este concepto, conocer los tipos que existen, qué otros trastornos suelen aparecer al mismo tiempo y qué tratamientos son los que dan mejores resultados

  14. Overcoming weak intrinsic depolarizing resonances with energy-jump

    International Nuclear Information System (INIS)

    Huang, H.; Ahrens, L.; Alessi, J.G.


    In the recent polarized proton runs in the AGS, a 5% partial snake was used successfully to overcome the imperfection depolarizing resonances. Polarized proton beam was accelerated up to the required RHIC injection energy of 25 GeV. However, significant amount of polarization was lost at 0+ν y , 12+ν y and 36+ν y , which is believed to be partially due to the coupling resonances. To overcome the coupling resonance, an energy-jump was generated by rapidly changing the beam circumference using the powerful AGS rf system. It clearly demonstrates that the novel energy-jump method can successfully overcome coupling resonances and weak intrinsic resonances

  15. Thermally stimulated depolarization currents in ThO2

    International Nuclear Information System (INIS)

    Campos, L.L.


    Thermally Stimulated Depolarization Currents (TSDC) have been detected in polycrystalline samples of ThO 2 in the temperature range 100K - 350K. The induced polarization is found to be due to migration of charge carriers over microscopic distances with trapping at grain boundaries. Moreover the density of charges carriers released from trapping sites, upon heating the cooled previously dc biased specimen, decreases for increasing sintering temperature, suggesting the use of the technique to the study of grain growth in the bulk of ceramic nuclear oxides [pt

  16. Concentration depolarization of luminescence of Eu3+-doped glasses

    International Nuclear Information System (INIS)

    Bodunov, E.N.; Lebedev, V.P.; Malyshev, V.A.; Przheuskij, A.K.


    Experimental study of concentrational depolarization luminescence (CDL) of phosphate and germanate glasses, containing Eu 3+ ions, has been carried out. On the basis of three-body self-consistent approximation the theory of CDL is conceived, which takes into account Eu-Eu interaction of higher multipolarities. By comparing the theory with the experiment energy transfer radii for Eu-Eu dipole-dipole, dipole-quadrupole and quadrupole-quadrupole interactions are determined. The attempt to discriminate Eu-Eu interaction types in the studied range of Eu 3+ ion concentration change has failed owing to law accuracy of luminescence emittance anisotropy measurement

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

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


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

  18. Depolarization of fluorescence of polyatomic molecules in noble gas solvents (United States)

    Blokhin, A. P.; Gelin, M. F.; Kalosha, I. I.; Matylitsky, V. V.; Erohin, N. P.; Barashkov, M. V.; Tolkachev, V. A.


    The collisional depolarization of fluorescence is studied for p-quarterphenyl (PQP) in He, Ar, Xe solvents, under pressures ranging from zero to nearly atmospheric. The results are interpreted within the Keilson-Storer model of the orientational relaxation and smooth rigid body collision dynamics. This allows us to estimate the rate of the angular momentum scrambling due to encounters of PQP with its partners. The collisions are shown to be neither strong nor weak, so that the averaged number of encounters giving rise to the PQP angular momentum randomization equals to 33 (PQP-He), 4.5 (PQP-Ar), and 2.1 (PQP-Xe).



    Said Broumi; Mohamed Talea; Assia Bakali; Florentin Smarandache


    In this article, we combine the concept of bipolar neutrosophic set and graph theory. We introduce the notions of bipolar single valued neutrosophic graphs, strong bipolar single valued neutrosophic graphs, complete bipolar single valued neutrosophic graphs, regular bipolar single valued neutrosophic graphs and investigate some of their related properties.

  20. Oxide bipolar electronics: materials, devices and circuits

    International Nuclear Information System (INIS)

    Grundmann, Marius; Klüpfel, Fabian; Karsthof, Robert; Schlupp, Peter; Schein, Friedrich-Leonhard; Splith, Daniel; Yang, Chang; Bitter, Sofie; Von Wenckstern, Holger


    We present the history of, and the latest progress in, the field of bipolar oxide thin film devices. As such we consider primarily pn-junctions in which at least one of the materials is a metal oxide semiconductor. A wide range of n-type and p-type oxides has been explored for the formation of such bipolar diodes. Since most oxide semiconductors are unipolar, challenges and opportunities exist with regard to the formation of heterojunction diodes and band lineups. Recently, various approaches have led to devices with high rectification, namely p-type ZnCo 2 O 4 and NiO on n-type ZnO and amorphous zinc-tin-oxide. Subsequent bipolar devices and applications such as photodetectors, solar cells, junction field-effect transistors and integrated circuits like inverters and ring oscillators are discussed. The tremendous progress shows that bipolar oxide electronics has evolved from the exploration of various materials and heterostructures to the demonstration of functioning integrated circuits. Therefore a viable, facile and high performance technology is ready for further exploitation and performance optimization. (topical review)

  1. Analysis of spin depolarizing effects in electron storage rings

    International Nuclear Information System (INIS)

    Boege, M.


    In this thesis spin depolarizing effects in electron storage rings are analyzed and the depolarizing effects in the HERA electron storage ring are studied in detail. At high beam energies the equilibrium polarization is limited by nonlinear effects. This will be particularly true in the case of HERA, when the socalled ''spin rotators'' are inserted which are designed to provide longitudinal electron polarization for the HERMES experiment in 1994 and later for the H1 and ZEUS experiment. It is very important to quantify the influence of these effects theoretically by a proper modelling of HERA, so that ways can be found to get a high degree of polarization in the real machine. In this thesis HERA is modelled by the Monte-Carlo tracking program SITROS which was originally written by J. Kewisch in 1982 to study the polarization in PETRA. The first part of the thesis is devoted to a detailed description of the fundamental theoretical concepts on which the program is based. Then the approximations which are needed to overcome computing time limitations are explained and their influence on the simulation result is discussed. The systematic and statistical errors are studied in detail. Extensions of the program which allow a comparison of SITROS with the results given by ''linear'' theory are explained. (orig.)

  2. Storage ring lattice calibration using resonant spin depolarization

    Directory of Open Access Journals (Sweden)

    K. P. Wootton


    Full Text Available This paper presents measurements of the GeV-scale electron beam energy for the storage rings at the synchrotron light source facilities Australian Synchrotron (AS and SPEAR3 at SLAC. Resonant spin depolarization was employed in the beam energy measurement, since it is presently the highest precision technique and an uncertainty of order 10^{-6} was achieved at SPEAR3 and AS. Using the resonant depolarization technique, the beam energy was measured at various rf frequencies to measure the linear momentum compaction factor. This measured linear momentum compaction factor was used to evaluate models of the beam trajectory through combined-function bending magnets. The main bending magnets of both lattices are rectangular, horizontally defocusing gradient bending magnets. Four modeling approaches are compared for the beam trajectory through the bending magnet: a circular trajectory, linear and nonlinear hyperbolic cosine trajectories, and numerical evaluation of the trajectory through the measured magnetic field map. Within the uncertainty of the measurement the momentum compaction factor is shown to agree with the numerical model of the trajectory within the bending magnet, and disagree with the hyperbolic cosine approximation.

  3. Calibration procedure and wavelength correction for neutron depolarization experiments

    International Nuclear Information System (INIS)

    Roest, W.; Rekveldt, M.T.


    The neutron polarimeter, for which an extended calibration procedure is described here, enables one to investigate magnetic properties of materials. Such an investigation is carried out by offering a polarized neutron beam in the x-, y- and z-direction successively and, after transmission through the sample, by analysing the polarization in all three directions. The result is a 3x3 depolarization matrix. After the polarizer, the neutron beam has a polarization along the z-direction. Two coil systems creating a magnetic field in the yz-plane perpendicular to the beam direction provide the possibility to direct the polarization in the x-, y- and z-direction by means of Larmor precession of the polarization in these fields. New research areas, where small depolarization effects together with considerable polarization rotation are measured, have caused a need for more accuracy in, and better knowledge of the calibration of the polarimeter. The calibration procedure use up to now and the improvements made on it are described. (orig.)

  4. Life expectancy in bipolar disorder

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Vradi, Eleni; Andersen, Per Kragh


    OBJECTIVE: Life expectancy in patients with bipolar disorder has been reported to be decreased by 11 to 20 years. These calculations are based on data for individuals at the age of 15 years. However, this may be misleading for patients with bipolar disorder in general as most patients have a later...... onset of illness. The aim of the present study was to calculate the remaining life expectancy for patients of different ages with a diagnosis of bipolar disorder. METHODS: Using nationwide registers of all inpatient and outpatient contacts to all psychiatric hospitals in Denmark from 1970 to 2012 we...... remaining life expectancy in bipolar disorder and that of the general population decreased with age, indicating that patients with bipolar disorder start losing life-years during early and mid-adulthood. CONCLUSIONS: Life expectancy in bipolar disorder is decreased substantially, but less so than previously...

  5. Bipolar nickel-hydrogen battery development (United States)

    Koehler, C. W.; Applewhite, A. Z.; Hall, A. M.; Russell, P. G.


    A comparison of the bipolar Ni-H2 battery with other energy systems to be used in future high-power space systems is presented. The initial design for the battery under the NASA-sponsored program is described and the candidate stack components are evaluated, including electrodes, separator, electrolyte reservoir plate, and recombination sites. The compressibility of the cell elements, electrolyte activation, and thermal design are discussed. Manufacturing and prototype test results are summarized.

  6. [Bipolar disorder in adolescence]. (United States)

    Brunelle, Julie; Milhet, Vanessa; Consoli, Angèle; Cohen, David


    Juvenile mania is a concept widely developed but also highly debated since the 1990s. In the heart of this debate, Severe Mood Dysregulation (SMD) and "Temper Dysregulation disorder with Dysphoria" (recently integrated in DSM-5) showed their interest. Actually, the objective is to distinguish two clinical phenotypes in order to avoid confusion between (1) what would raise more of mood dysregulation with chronic manic like symptoms, and (2) bipolar disorder type I with episodic and acute manic episodes. Therapeutic stakes are major. In adolescents, even if DSM adult diagnostic criteria can be used and bipolar disorder type I clearly established, differential diagnostic at onset between acute manic episode and schizophrenia onset remain sometimes difficult to assess. Furthermore, it is crucial to better assess outcome of these adolescents, in terms of morbidity and potential prognosis factors, knowing that a younger age at onset is associated with a poorer outcome according to several adult studies. Therapeutic implications could then be drawn.

  7. Depressive and bipolar disorders

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Hansen, Hanne Vibe; Demyttenaere, Koen


    of the patients (40-80%) had erroneous views as to the effect of antidepressants. Older patients (over 40 years of age) consistently had a more negative view of the doctor-patient relationship, more erroneous ideas concerning the effect of antidepressants and a more negative view of antidepressants in general....... Moreover, their partners agreed on these negative views. Women had a more negative view of the doctor-patient relationship than men, and patients with a depressive disorder had a more negative view of antidepressants than patients with bipolar disorder. The number of psychiatric hospitalizations......BACKGROUND: There is increasing evidence that attitudes and beliefs are important in predicting adherence to treatment and medication in depressive and bipolar disorders. However, these attitudes have received little study in patients whose disorders were sufficiently severe to require...

  8. [Creativity and bipolar disorder]. (United States)

    Maçkalı, Zeynep; Gülöksüz, Sinan; Oral, Timuçin


    The relationship between creativity and bipolar disorder has been an intriguing topic since ancient times. Early studies focused on describing characteristics of creative people. From the last quarter of the twentieth century, researchers began to focus on the relationship between mood disorders and creativity. Initially, the studies were based on biographical texts and the obtained results indicated a relationship between these two concepts. The limitations of the retrospective studies led the researchers to develop systematic investigations into this area. The systematic studies that have focused on artistic creativity have examined both the prevalence of mood disorders and the creative process. In addition, a group of researchers addressed the relationship in terms of affective temperaments. Through the end of the 90's, the scope of creativity was widened and the notion of everyday creativity was proposed. The emergence of this notion led researchers to investigate the associations of the creative process in ordinary (non-artist) individuals. In this review, the descriptions of creativity and creative process are mentioned. Also, the creative process is addressed with regards to bipolar disorder. Then, the relationship between creativity and bipolar disorder are evaluated in terms of aforementioned studies (biographical, systematic, psychobiographical, affective temperaments). In addition, a new model, the "Shared Vulnerability Model" which was developed to explain the relationship between creativity and psychopathology is introduced. Finally, the methodological limitations and the suggestions for resolving these limitations are included.

  9. Contribution of α-adrenoceptors to depolarization and contraction evoked by continuous asynchronous sympathetic nerve activity in rat tail artery (United States)

    Brock, J A; McLachlan, E M; Rayner, S E


    The effects of continuous but asynchronous nerve activity induced by ciguatoxin (CTX-1) on the membrane potential and contraction of smooth muscle cells have been investigated in rat proximal tail arteries isolated in vitro. These effects have been compared with those produced by the continuous application of phenylephrine (PE).CTX-1 (0.4 nM) and PE (10 μM) produced a maintained depolarization of the arterial smooth muscle that was almost completely blocked by α-adrenoceptor blockade. In both cases, the depolarization was more sensitive to the selective α2-adrenoceptor antagonist, idazoxan (0.1 μM), than to the selective α1-adrenoceptor antagonist, prazosin (0.01 μM).In contrast, the maintained contraction of the tail artery induced by CTX-1 (0.2 nM) and PE (2 and 10 μM) was more sensitive to prazosin (0.01) μM, than to idazoxan (0.01 μM). In combination, these antagonists almost completely inhibited contraction to both agents.Application of the calcium channel antagonist, nifedipine (1 μM), had no effect on the depolarization induced by either CTX-1 or PE but maximally reduced the force of the maintained contraction to both agents by about 50%.We conclude that the constriction of the tail artery induced by CTX-1, which mimics the natural discharge of postganglionic perivascular axons, is due almost entirely to α-adrenoceptor activation. The results indicate that neuronally released noradrenaline activates more than one α-adrenoceptor subtype. The depolarization is dependent primarily on α2-adrenoceptor activation whereas the contraction is dependent primarily on α1-adrenoceptor activation. The links between α-adrenoceptor activation and the voltage-dependent and voltage-independent mechanisms that deliver Ca2+ to the contractile apparatus appear to be complex. PMID:9113373

  10. The bipolar plate of AISI 1045 steel with chromized coatings prepared by low-temperature pack cementation for proton exchange membrane fuel cell (United States)

    Bai, Ching-Yuan; Wen, Tse-Min; Hou, Kung-Hsu; Ger, Ming-Der

    The low-temperature pack chromization, a reforming pack cementation process, is employed to modify AISI 1045 steel for the application of bipolar plates in PEMFC. The process is conducted to yield a coating, containing major Cr-carbides and minor Cr-nitrides, on the substrate in view of enhancing the steel's corrosion resistance and lowering interfacial contact resistance between the bipolar plate and gas diffusion layer. Electrical discharge machining and rolling approach are used as the pretreatment to produce an activated surface on the steel before pack chromization process to reduce operating temperatures and increase deposition rates. The rolled-chromized steel shows the lowest corrosion current density, 3 × 10 -8 A cm -2, and the smallest interfacial contact resistance, 5.9 mΩ cm 2, at 140 N cm -2 among all tested steels. This study clearly states the performance of 1045 carbon steel modified by activated and low-temperature pack chromization processes, which possess the potential to be bipolar plates in the application of PEMFC.

  11. The bipolar plate of AISI 1045 steel with chromized coatings prepared by low-temperature pack cementation for proton exchange membrane fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Ching-Yuan; Ger, Ming-Der [Department of Chemistry and Materials Science and Engineering, Chung Cheng Institute of Technology, National Defense University, Tau-Yuan 335 (China); Wen, Tse-Min [School of Defense Science, Chung Cheng Institute of Technology, National Defense University, Tao-Yuan 335 (China); Hou, Kung-Hsu [Department of Power Vehicles and System Engineering, Chung Cheng Institute of Technology, National Defense University, Tao-Yuan 335 (China)


    The low-temperature pack chromization, a reforming pack cementation process, is employed to modify AISI 1045 steel for the application of bipolar plates in PEMFC. The process is conducted to yield a coating, containing major Cr-carbides and minor Cr-nitrides, on the substrate in view of enhancing the steel's corrosion resistance and lowering interfacial contact resistance between the bipolar plate and gas diffusion layer. Electrical discharge machining and rolling approach are used as the pretreatment to produce an activated surface on the steel before pack chromization process to reduce operating temperatures and increase deposition rates. The rolled-chromized steel shows the lowest corrosion current density, 3 x 10{sup -8} A cm{sup -2}, and the smallest interfacial contact resistance, 5.9 m{omega} cm{sup 2}, at 140 N cm{sup -2} among all tested steels. This study clearly states the performance of 1045 carbon steel modified by activated and low-temperature pack chromization processes, which possess the potential to be bipolar plates in the application of PEMFC. (author)

  12. Rayleigh scattering and depolarization ratio in linear alkylbenzene

    International Nuclear Information System (INIS)

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


    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

  13. Linear Depolarization of Lidar Returns by Aged Smoke Particles (United States)

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


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

  14. Chloride regulates afferent arteriolar contraction in response to depolarization

    DEFF Research Database (Denmark)

    Hansen, P B; Jensen, B L; Skott, O


    -Renal vascular reactivity is influenced by the level of dietary salt intake. Recent in vitro data suggest that afferent arteriolar contractility is modulated by extracellular chloride. In the present study, we assessed the influence of chloride on K+-induced contraction in isolated perfused rabbit...... afferent arterioles. In 70% of vessels examined, K+-induced contraction was abolished by acute substitution of bath chloride. Consecutive addition of Cl- (30, 60, 80, 100, 110, and 117 mmol/L) restored the sensitivity to K+, and half-maximal response was observed at 82 mmol/L chloride. The calcium channel...... antagonist diltiazem (10(-6) mol/L) abolished K+-induced contractions. Bicarbonate did not modify the sensitivity to chloride. Norepinephrine (10(-6) mol/L) induced full contraction in depolarized vessels even in the absence of chloride. Iodide and nitrate were substituted for chloride with no inhibitory...

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

    Energy Technology Data Exchange (ETDEWEB)

    Brandenburg, Axel; Ashurova, Mohira B. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States); Jabbari, Sarah, E-mail: [School of Mathematical Sciences and Monash Centre for Astrophysics, Monash University, Clayton, VIC 3800 (Australia)


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

  16. Scientific attitudes towards bipolar disorders

    Directory of Open Access Journals (Sweden)

    Mohammad-Hossein Biglu


    Full Text Available Introduction: Bipolar disorder is a psychiatric condition that is also called manic-depressive disease. It causes unusual changes in mood, energy, activity levels, and the ability to carry out day-to-day tasks. In the present study, 3 sets of data were considered and analyzed: first, all papers categorized under Bipolar Disorders in Science Citation Index Expanded (SCI-E database through 2001-2011; second, papers published by the international journal of Bipolar Disorders indexed in SCI-E during a period of 11 years; and third, all papers distributed by the international journal of Bipolar Disorders indexed in MEDLINE during the period of study. Methods: The SCI-E database was used to extract all papers indexed with the topic of Bipolar Disorders as well as all papers published by The International Journal of Bipolar Disorders. Extraction of data from MEDLINE was restricted to the journals name from setting menu. The Science of Science Tool was used to map the co-authorship network of papers published by The International Journal of Bipolar Disorders through 2009-2011. Results: Analysis of data showed that the majority of publications in the subject area of bipolar disorders indexed in SCI-E were published by The International Journal of Bipolar Disorders. Although journal articles consisted of 59% of the total publication type in SCI-E, 65% of publications distributed by The Journal of Bipolar Disorders were in the form of meetingabstracts. Journal articles consisted of only 23% of the total publications. USA was the leading country regarding sharing data in the field of bipolar disorders followed by England, Canada, and Germany. Conclusion: The editorial policy of The International Journal of Bipolar Disorders has been focused on new themes and new ways of researching in the subject area of bipolar disorder. Regarding the selection of papers for indexing, the SCI-E database selects data more comprehensively than MEDLINE. The number of papers

  17. Epidemiology in Pediatric Bipolar Disorder

    Directory of Open Access Journals (Sweden)

    Caner Mutlu


    Full Text Available Childhood and adolescent bipolar disorder diagnosis has been increasing recently. Since studies evaluating attempted suicide rates in children and adolescents have shown bipolarity to be a significant risk factor, diagnosis and treatment of bipolarity has become a very important issue. Since there is a lack of specific diagnostic criteria for especially preadolescent samples and evaluations are made mostly symptomatically, suspicions about false true diagnosis and increased prevalence rates have emerged. This situation leads to controversial data about the prevalence rates of bipolar disorder in children and adolescents. The aim of this article is to review the prevalence of childhood and adolescent bipolar disorder in community, inpatient and outpatient based samples in literature.

  18. Depolarization due to the resonance tail during a fast resonance jump

    International Nuclear Information System (INIS)

    Ruth, R.D.


    The mechanism of depolarization due to a fast resonance jump is studied. The dominant effect for cases of interest is not dependent on the rate of passage through resonance, but rather on the size of the resonance jump as compared to the width, epsilon, of the resonance. The results are applied to a calculation of depolarization in the AGS at Brookhaven National Laboratory

  19. Dependence of negative muon depolarization on molecular weight and temperature in organic compounds

    International Nuclear Information System (INIS)

    Djuraev, A.A.; Evseev, V.S.; Obukhov, Yu.V.; Roganov, V.S.


    An atomic capture of negative muons in the aliphatic spirit series, the dependence of muon rest polarization on the molecular weight of spirit have been studied. The temperature dependence of depolarization in benzole and styrene has been obtained. The results on depolarization are being interpreted basing on notions about chemical interactions of mesic atoms in organic compounds. (author)

  20. Simple non-Markovian microscopic models for the depolarizing channel of a single qubit

    International Nuclear Information System (INIS)

    Fonseca Romero, K M; Lo Franco, R


    The archetypal one-qubit noisy channels - depolarizing, phase-damping and amplitude-damping channels - describe both Markovian and non-Markovian evolution. Simple microscopic models for the depolarizing channel, both classical and quantum, are considered. Microscopic models that describe phase-damping and amplitude-damping channels are briefly reviewed.

  1. A rotational diffusion coefficient of the 70s ribosome determined by depolarized laser light scattering

    NARCIS (Netherlands)

    Bruining, J.; Fijnaut, H.M.

    We have obtained a rotational diffusion coefficient of the 70S ribosome isolated from Escherichia-coli (MRE-600), from the depolarized light scattering spectrum measured by photon correlation spectroscopy. The intensity correlation function of depolarized scattered light contains contributions due

  2. Genetics of bipolar disorder

    Directory of Open Access Journals (Sweden)

    Kerner B


    Full Text Available Berit Kerner Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, Los Angeles, CA, USA Abstract: Bipolar disorder is a common, complex genetic disorder, but the mode of transmission remains to be discovered. Many researchers assume that common genomic variants carry some risk for manifesting the disease. The research community has celebrated the first genome-wide significant associations between common single nucleotide polymorphisms (SNPs and bipolar disorder. Currently, attempts are under way to translate these findings into clinical practice, genetic counseling, and predictive testing. However, some experts remain cautious. After all, common variants explain only a very small percentage of the genetic risk, and functional consequences of the discovered SNPs are inconclusive. Furthermore, the associated SNPs are not disease specific, and the majority of individuals with a “risk” allele are healthy. On the other hand, population-based genome-wide studies in psychiatric disorders have rediscovered rare structural variants and mutations in genes, which were previously known to cause genetic syndromes and monogenic Mendelian disorders. In many Mendelian syndromes, psychiatric symptoms are prevalent. Although these conditions do not fit the classic description of any specific psychiatric disorder, they often show nonspecific psychiatric symptoms that cross diagnostic boundaries, including intellectual disability, behavioral abnormalities, mood disorders, anxiety disorders, attention deficit, impulse control deficit, and psychosis. Although testing for chromosomal disorders and monogenic Mendelian disorders is well established, testing for common variants is still controversial. The standard concept of genetic testing includes at least three broad criteria that need to be fulfilled before new genetic tests should be introduced: analytical validity, clinical validity, and clinical utility. These criteria are

  3. Early Intervention in Bipolar Disorder. (United States)

    Vieta, Eduard; Salagre, Estela; Grande, Iria; Carvalho, André F; Fernandes, Brisa S; Berk, Michael; Birmaher, Boris; Tohen, Mauricio; Suppes, Trisha


    Bipolar disorder is a recurrent disorder that affects more than 1% of the world population and usually has its onset during youth. Its chronic course is associated with high rates of morbidity and mortality, making bipolar disorder one of the main causes of disability among young and working-age people. The implementation of early intervention strategies may help to change the outcome of the illness and avert potentially irreversible harm to patients with bipolar disorder, as early phases may be more responsive to treatment and may need less aggressive therapies. Early intervention in bipolar disorder is gaining momentum. Current evidence emerging from longitudinal studies indicates that parental early-onset bipolar disorder is the most consistent risk factor for bipolar disorder. Longitudinal studies also indicate that a full-blown manic episode is often preceded by a variety of prodromal symptoms, particularly subsyndromal manic symptoms, therefore supporting the existence of an at-risk state in bipolar disorder that could be targeted through early intervention. There are also identifiable risk factors that influence the course of bipolar disorder, some of them potentially modifiable. Valid biomarkers or diagnosis tools to help clinicians identify individuals at high risk of conversion to bipolar disorder are still lacking, although there are some promising early results. Pending more solid evidence on the best treatment strategy in early phases of bipolar disorder, physicians should carefully weigh the risks and benefits of each intervention. Further studies will provide the evidence needed to finish shaping the concept of early intervention. AJP AT 175 Remembering Our Past As We Envision Our Future April 1925: Interpretations of Manic-Depressive Phases Earl Bond and G.E. Partridge reviewed a number of patients with manic-depressive illness in search of a unifying endo-psychic conflict. They concluded that understanding either phase of illness was "elusive" and

  4. Novel multiple criteria decision making methods based on bipolar neutrosophic sets and bipolar neutrosophic graphs


    Muhammad, Akram; Musavarah, Sarwar


    In this research study, we introduce the concept of bipolar neutrosophic graphs. We present the dominating and independent sets of bipolar neutrosophic graphs. We describe novel multiple criteria decision making methods based on bipolar neutrosophic sets and bipolar neutrosophic graphs. We also develop an algorithm for computing domination in bipolar neutrosophic graphs.

  5. Spreading depolarizations have prolonged direct current shifts and are associated with poor outcome in brain trauma

    DEFF Research Database (Denmark)

    Hartings, Jed A; Watanabe, Tomas; Bullock, M Ross


    , although prolonged events have not been observed in animal models. To determine whether detrimental penumbral-type depolarizations occur in human brain trauma, we analysed electrocorticographic recordings obtained by subdural electrode-strip monitoring during intensive care. Of 53 patients studied, 10......Cortical spreading depolarizations occur spontaneously after ischaemic, haemorrhagic and traumatic brain injury. Their effects vary spatially and temporally as graded phenomena, from infarction to complete recovery, and are reflected in the duration of depolarization measured by the negative direct...... current shift of electrocorticographic recordings. In the focal ischaemic penumbra, peri-infarct depolarizations have prolonged direct current shifts and cause progressive recruitment of the penumbra into the core infarct. In traumatic brain injury, the effects of spreading depolarizations are unknown...

  6. Feasibility investigations on a novel micro-manufacturing process for fabrication of fuel cell bipolar plates: Internal pressure-assisted embossing of micro-channels with in-die mechanical bonding

    Energy Technology Data Exchange (ETDEWEB)

    Koc, Muammer [NSF I/UCR Center for Precision Forming (CPF), Department of Mechanical Engineering, Virginia Commonwealth University (VCU), Richmond, VA (United States); Mahabunphachai, Sasawat [NSF I/UCR Center for Precision Forming (CPF), Department of Mechanical Engineering, Virginia Commonwealth University (VCU), Richmond, VA (United States); Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI (United States)


    In this paper, we present the results of our studies on conceptual design and feasibility experiments towards development of a novel hybrid manufacturing process to fabricate fuel cell bipolar plates that consists of multi-array micro-channels on a large surface area. The premises of this hybrid micro-manufacturing process stem from the use of an internal pressure-assisted embossing process (cold or warm) combined with mechanical bonding of double bipolar plates in a single-die and single-step operation. Such combined use of hydraulic and mechanical forming forces and in-process bonding will (a) enable integrated forming of micro-channels on both surfaces (as anode and cathode flow fields) and at the middle (as cooling channels), (b) reduce the process steps, (c) reduce variation in dimensional tolerances and surface finish, (d) increase the product quality, (e) increase the performance of fuel cell by optimizing flow-field designs and ensuring consistent contact resistance, and (f) reduce the overall stack cost. This paper explains two experimental investigations that were performed to characterize and evaluate the feasibility of the conceptualized manufacturing process. The first investigation involved hydroforming of micro-channels using thin sheet metals of SS304 with a thickness of 51 {mu}m. The width of the channels ranged from 0.46 to 1.33 mm and the height range was between 0.15 and 0.98 mm. Our feasibility experiments resulted in that different aspect ratios of micro-channels could be fabricated using internal pressure in a controllable manner although there is a limit to very sharp channel shapes (i.e., high aspect ratios with narrow channels). The second investigation was on the feasibility of mechanical bonding of thin sheet metal blanks. The effects of different process and material variables on the bond quality were studied. Successful bonding of various metal blanks (Ni201, Al3003, and SS304) was obtained. The experimental results from both

  7. Bipolar pulse forming line (United States)

    Rhodes, Mark A.


    A bipolar pulse forming transmission line module for linear induction accelerators having first, second, third, fourth, and fifth planar conductors which form an interleaved stack with dielectric layers between the conductors. Each conductor has a first end, and a second end adjacent an acceleration axis. The first and second planar conductors are connected to each other at the second ends, the fourth and fifth planar conductors are connected to each other at the second ends, and the first and fifth planar conductors are connected to each other at the first ends via a shorting plate adjacent the first ends. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short a high voltage from the first end of the third planar conductor to the first end of the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  8. Bipolar and monopolar radiofrequency treatment of osteoarthritic knee articular cartilage: acute and temporal effects on cartilage compressive stiffness, permeability, cell synthesis, and extracellular matrix composition. (United States)

    Cook, James L; Kuroki, Keiichi; Kenter, Keith; Marberry, Kevin; Brawner, Travis; Geiger, Timothy; Jayabalan, Prakash; Bal, B Sonny


    The cellular, biochemical, biomechanical, and histologic effects of radiofrequency-generated heat on osteoarthritic cartilage were assessed. Articular cartilage explants (n=240) from 26 patients undergoing total knee arthroplasty were divided based on Outerbridge grade (I or II/III) and randomly assigned to receive no treatment (controls) or monopolar or bipolar radiofrequency at 15 or 30 W. Both potentially beneficial and harmful effects of radiofrequency treatment of articular cartilage were noted. It will be vital to correlate data from in vitro and in vivo study of radiofrequency thermal chondroplasty to determine the clinical usefulness of this technique.

  9. Bipolar nickel-hydrogen battery design (United States)

    Koehler, C. W.; Applewhite, A. Z.; Kuo, Y.


    The initial design for the NASA-Lewis advanced nickel-hydrogen battery is discussed. Fabrication of two 10-cell boilerplate battery stacks will soon begin. The test batteries will undergo characterization testing and low Earth orbit life cycling. The design effectively deals with waste heat generated in the cell stack. Stack temperatures and temperature gradients are maintained to acceptable limits by utilizing the bipolar conduction plate as a heat path to the active cooling fluid panel external to the edge of the cell stack. The thermal design and mechanical design of the battery stack together maintain a materials balance within the cell. An electrolyte seal on each cell frame prohibits electrolyte bridging. An oxygen recombination site and electrolyte reservoir/separator design does not allow oxygen to leave the cell in which it was generated.

  10. Tritium separation from light and heavy water by bipolar electrolysis

    International Nuclear Information System (INIS)

    Petek, M.; Ramey, D.W.; Taylor, R.D.


    Using multiple bipolar electrolytic separation of hydrogen isotopes with Pd-25%Ag electrodes, the mathematical feasibility of this method for tritium separation was shown and experimentally verified. Separation factors were measured on single bipolar electrodes and were found to be approximately equivalent to those associated with individual ordinary electrolytic systems. Multibipolar separations were experimentally achieved in single cascaded cells in which each bipolar electrode was of equal area to others in a series arrangement. Factors measured for multibipolar H-D separation were close to the values measured in single-stage cell measurements; for H-T separation, interstage leakage reduced the measured separation factor. However, in both cases separation of sufficient magnitude was achieved to show feasibility for real application to the extraction of tritium from large-volume systems at high current density. (author)

  11. Thermal conductivity of a graphite bipolar plate (BPP) and its thermal contact resistance with fuel cell gas diffusion layers: Effect of compression, PTFE, micro porous layer (MPL), BPP out-of-flatness and cyclic load (United States)

    Sadeghifar, Hamidreza; Djilali, Ned; Bahrami, Majid


    This paper reports on measurements of thermal conductivity of a graphite bipolar plate (BPP) as a function of temperature and its thermal contact resistance (TCR) with treated and untreated gas diffusion layers (GDLs). The thermal conductivity of the BPP decreases with temperature and its thermal contact resistance with GDLs, which has been overlooked in the literature, is found to be dominant over a relatively wide range of compression. The effects of PTFE loading, micro porous layer (MPL), compression, and BPP out-of-flatness are also investigated experimentally. It is found that high PTFE loadings, MPL and even small BPP out-of-flatness increase the BPP-GDL thermal contact resistance dramatically. The paper also presents the effect of cyclic load on the total resistance of a GDL-BPP assembly, which sheds light on the behavior of these materials under operating conditions in polymer electrolyte membrane fuel cells.

  12. Asenapine for bipolar disorder

    Directory of Open Access Journals (Sweden)

    Scheidemantel T


    Full Text Available Thomas Scheidemantel,1 Irina Korobkova,2 Soham Rej,3,4 Martha Sajatovic1,2 1University Hospitals Case Medical Center, 2Case Western Reserve University School of Medicine, Cleveland, OH, USA; 3Department of Psychiatry, University of Toronto, Toronto, ON, 4Geri PARTy Research Group, Jewish General Hospital, Montreal, QC, Canada Abstract: Asenapine (Saphris® is an atypical antipsychotic drug which has been approved by the US Food and Drug Administration for the treatment of schizophrenia in adults, as well as the treatment of acute manic or mixed episodes of bipolar I in both adult and pediatric populations. Asenapine is a tetracyclic drug with antidopaminergic and antiserotonergic activity with a unique sublingual route of administration. In this review, we examine and summarize the available literature on the safety, efficacy, and tolerability of asenapine in the treatment of bipolar disorder (BD. Data from randomized, double-blind trials comparing asenapine to placebo or olanzapine in the treatment of acute manic or mixed episodes showed asenapine to be an effective monotherapy treatment in clinical settings; asenapine outperformed placebo and showed noninferior performance to olanzapine based on improvement in the Young Mania Rating Scale scores. There are limited data available on the use of asenapine in the treatment of depressive symptoms of BD, or in the maintenance phase of BD. The available data are inconclusive, suggesting the need for more robust data from prospective trials in these clinical domains. The most commonly reported adverse effect associated with use of asenapine is somnolence. However, the somnolence associated with asenapine use did not cause significant rates of discontinuation. While asenapine was associated with weight gain when compared to placebo, it appeared to be modest when compared to other atypical antipsychotics, and its propensity to cause increases in hemoglobin A1c or serum lipid levels appeared to be

  13. The anomalous depolarization anisotropy in the central backscattering area for turbid medium with Mie scatterers (United States)

    Wang, Xuezhen; Lai, Jiancheng; Song, Yang; Li, Zhenhua


    It is generally recognized that circularly polarized light is preferentially maintained over linearly polarized light in turbid medium with Mie scatterers. However, in this work, the anomalous depolarization anisotropy is reported in the backscattering area near the point of illumination. Both experimental and Monte Carlo simulations show preferential retention of linear polarization states compared to circular polarization states in a specific backscattering area. Further analysis indicates that the anomalous depolarization behavior in the specific area is induced by lateral scattering events, which own low circular polarization memory. In addition, it is also found that the size of the anomalous depolarization area is related to the transport mean free path of the turbid medium.

  14. Interaction between depolarization effects, interface layer, and fatigue behavior in PZT thin film capacitors (United States)

    Böttger, U.; Waser, R.


    The existence of non-ferroelectric regions in ferroelectric thin films evokes depolarization effects leading to a tilt of the P(E) hysteresis loop. The analysis of measured hysteresis of lead zirconate titanate (PZT) thin films is used to determine a depolarization factor which contains quantitative information about interfacial layers as well as ferroelectrically passive zones in the bulk. The derived interfacial capacitance is smaller than that estimated from conventional extrapolation techniques. In addition, the concept of depolarization is used for the investigation of fatigue behavior of PZT thin films indicating that the mechanism of seed inhibition, which is responsible for the effect, occurs in the entire film.

  15. Stacks with TiN/titanium as the bipolar plate for PEMFCs

    International Nuclear Information System (INIS)

    Ren, Zhijun; Zhang, Dongming; Wang, Zaiyi


    Proton exchange membrane fuel cell (PEMFC) is a potential alternative for the internal combustion engine. But many problems, such as metallic bipolar plate instead of graphite bipolar plate to decrease the cost, should be solved before its application. Based on the previous results that single cell with TiN/Ti as bipolar plates shows high performance and enough long-time durability, the progress on the stacks with TiN/Ti as bipolar plates is reported in this manuscript. Till now seldom report is focused on stacks because of the complicated processing technique, especially for that with TiN/Ti as bipolar plate. The flow field in the plate is punched from titanium deformation, and two plates are welded by laser welding to form one piece of bipolar plate. The adopted processing techniques for stacks with TiN/Ti as bipolar plate exhibit advantage and feasibility in industry. The power density by weight for the stack is as high as 1353 W kg −1 , although it still has space to be improved. Next work should be focused on the design of flow channel parameters and flow field type based on plastic deformation of metal materials. -- Highlights: ► The progress on the stacks with TiN/Ti as bipolar plates is reported. ► The adopted processing techniques exhibit feasibility in industry. ► The power density by weight for the stack is as high as 1353 W kg −1 .

  16. Bipolar plates for polymer electrolyte membrane fuel cells made of thermal and electrical high conductivity thermoplastics. Formulation, production, characterization and application; Bipolarplatten fuer Polymerelektrolytmembran-Brennstoffzellen aus thermisch und elektrisch hochleitfaehigen thermoplastischen Kunststoffen. Rezeptierung, Herstellung, Charakterisierung und Anwendung

    Energy Technology Data Exchange (ETDEWEB)

    Kaiser, Ralf Leonhard


    The upcoming lack of primary energy sources and the need of reducing the anthropogenic climate change led to increased research activities in the field of Fuel Cells (FC) technology within the last ten years in Europe, the USA and Japan. Especially the automotive industry is highly interested in developing zero emission cars as a replacement of nowadays cars within the next twenty years. Not only for mobile applications the Polymer Electrolyte Membrane Fuel Cell systems (PEM-FC systems) is the focus of research and development. Also stationary (PEM-) FC applications seem to be more and more interesting for a decentralized energy supply, producing electricity and heat (Vaillant FC-Systems, Bosch/Junkers). For this purpose, system miniaturizing and weight reduction (70-90 wt-% of the stack itself is due to bipolar- and endplate) is not that essential as it is for mobile appliance, resulting in earlier commercial market introduction of these systems within the next few years. Not only the weight reduction of the FC-stack itself, but also the cost cutting of its components is vital for the economic success of this technology. The three most expensive components of the stack are the perfluorsulfonated ion conducting Membranen (PEM: Nafion, Ashai, Ashai glass), the noble metal catalyst (Platinum and/or Ruthenium) and the Bipolar Plate (BPP). The moulding processes (injection and/or compression moulding) of polymer materials allow highly integrated, tool reduced mass production of tailored stack components like the BP, the endplate, cell frame and peripheral components. The objective of this thesis is to describe the development of an conductive functionalised material suitable for moulding BPP, to investigate compounding optimisation methods (DOE) and evaluate the best fit parameters, to analyse the rheological behaviour of these highly filled compounds, to discuss suitable polymer related manufacturing processes like hot pressing, injection moulding and profile

  17. Modeling suicide in bipolar disorders. (United States)

    Malhi, Gin S; Outhred, Tim; Das, Pritha; Morris, Grace; Hamilton, Amber; Mannie, Zola


    Suicide is a multicausal human behavior, with devastating and immensely distressing consequences. Its prevalence is estimated to be 20-30 times greater in patients with bipolar disorders than in the general population. The burden of suicide and its high prevalence in bipolar disorders make it imperative that our current understanding be improved to facilitate prediction of suicide and its prevention. In this review, we provide a new perspective on the process of suicide in bipolar disorder, in the form of a novel integrated model that is derived from extant knowledge and recent evidence. A literature search of articles on suicide in bipolar disorder was conducted in recognized databases such as Scopus, PubMed, and PsycINFO using the keywords "suicide", "suicide in bipolar disorders", "suicide process", "suicide risk", "neurobiology of suicide" and "suicide models". Bibliographies of identified articles were further scrutinized for papers and book chapters of relevance. Risk factors for suicide in bipolar disorders are well described, and provide a basis for a framework of epigenetic mechanisms, moderated by neurobiological substrates, neurocognitive functioning, and social inferences within the environment. Relevant models and theories include the diathesis-stress model, the bipolar model of suicide and the ideation-to-action models, the interpersonal theory of suicide, the integrated motivational-volitional model, and the three-step theory. Together, these models provide a basis for the generation of an integrated model that illuminates the suicidal process, from ideation to action. Suicide is complex, and it is evident that a multidimensional and integrated approach is required to reduce its prevalence. The proposed model exposes and provides access to components of the suicide process that are potentially measurable and may serve as novel and specific therapeutic targets for interventions in the context of bipolar disorder. Thus, this model is useful not only

  18. Bipolar explosion models for hypernovae

    International Nuclear Information System (INIS)

    Maeda, Keiichi; Nomoto, Ken'ichi


    Bipolar explosion models for hypernovae (very energetic supernovae) are presented. These models provide a favorable situation to explain some unexpected features in observations of hypernovae, e.g., high velocity matter dominated by Fe and low velocity matter dominated by O. The overall abundance of these models gives a good fit, at least qualitatively, to abundances in extremely metal-poor stars. We suggest hypernovae be driven by bipolar jets and contribute significantly to the early Galactic chemical evolution

  19. Functional remediation for bipolar disorder


    Martínez-Arán, Anabel, 1971-; Torrent, C.; Solé, B.; Bonnín, C.M.; Rosa, A.R.; Sánchez-Moreno, J.; Vieta i Pascual, Eduard, 1963-


    Neurocognitive impairment constitutes a core feature of bipolar illness. The main domains affected are verbal memory, attention, and executive functions. Deficits in these areas as well as difficulties to get functional remission seem to be increased associated with illness progression. Several studies have found a strong relationship between neurocognitive impairment and low functioning in bipolar disorder, as previously reported in other illnesses such as schizophrenia. Cognitive remediatio...

  20. Thermally stimulated depolarization currents in the natural fluorite

    International Nuclear Information System (INIS)

    Valerio, Mario Ernesto Giroldo


    The present work deals with natural calcium fluoride from Criciuma, Santa Catarina. Thermally Stimulated Depolarization Currents (TSDC) can be used to determine the properties of dipole defects present in this crystal. The TSDC spectrum of this material shows three bands in the temperature range of 80 to 450 K. The first one, at 130 K, is due the dipoles formed by a trivalent impurity and an interstitial fluorine ion in the next nearest position of an impurity ion (nn R s 3+ -F i - ). The second one, at 102 k, is due to the presence of small aggregates of dipoles (like a dimer). The last band, at 360 k is due to the formation of Large Clusters. The continuous distribution model gave the best fit for these bands with mean activation energies of 0.41 eV, 0.595 eV and 1.02 eV for the first, second and third band respectively. Thermal treatments can modify the number of dipoles, dimers and clusters present in the crystal. The variation in the areas under each band can be used to measure this effect. In this work we used thermal treatments between 15 minutes and 10 hours and temperatures between 200 deg C and 500 deg C. For thermal treatments at 300 deg C, the dipoles and dimers are created and the clusters are destroyed as the time of thermal treatment increases. At 400 deg C the clusters are created and the dipoles and dimers and 350 deg C for the clusters. (author)

  1. Speed of disentanglement in multiqubit systems under a depolarizing channel

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fu-Lin, E-mail:; Jiang, Yue; Liang, Mai-Lin, E-mail:


    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)

  2. Study of the cathodic depolarization theory with hydrogen permeation and the bacteria Desulfovibrio desulfuricans

    International Nuclear Information System (INIS)

    Romero, M. F. de; Duque, Z.; Rinco, O. T. de; Perez, O.; Araujo, I.


    A Desulfovibrio desulfuricans ssp. desulfuricans (SRB) was used to study the permeation of hydrogen, using a Devanatan and Stachurski cell and a palladium sheet. The aim was to evaluate cathodic depolarization as a Sulfate-Reducing Bacteria action mechanisms in Microbiologically Induced Corrosion. The permeation tests were run with and without cathodic polarization, using a sterile deaerated culture medium inoculated with 10% SRB concentrated at 10''8 cell/ml. the results indicate bacterial growth in the order of 10''9-10''10 cel/ml after 18 h both in the polarized and non-polarized, tests, indicating that SRB developed regardless of the surface polarized as a source of H''0, generating H 2 S as a product of the anaerobic respiration. It was also determined that, without cathodic polarization, the conditions are not enough to reduce the H* generated by the H 2 S dissociation (pd is not susceptible to corrosion at this condition). On the other hand, cathodic polarization increased the permeation current, which was associated with the maximum enzymatic activity phase of the bacteria. (Author) 8 refs

  3. Multikilowatt Bipolar Nickel/Hydrogen Battery (United States)


    High energy densities appear feasible. Nickel/hydrogen battery utilizing bipolar construction in common pressure vessel, addressing needs for multikilowatt storage for low-Earth-orbit applications, designed and 10-cell prototype model tested. Modular-concept-design 35-kW battery projected energy densities of 20 to 24 Wh/b (160 to 190 kj/kg) and 700 to 900 Wh/ft3 (90 to 110 MJ/m3) and incorporated significant improvements over state-of-the-art storage systems.

  4. Study on in-situ electrochemical impedance spectroscopy measurement of anodic reaction in SO_2 depolarized electrolysis process

    International Nuclear Information System (INIS)

    Xue Lulu; Zhang Ping; Chen Songzhe; Wang Laijun


    SO_2 depolarized electrolysis (SDE) is the pivotal reaction in hybrid sulfur process, one of the most promising approaches for mass hydrogen production without CO_2 emission. The net result of hybrid sulfur process is to split water into hydrogen and oxygen at a relatively low voltage, which will dramatically decrease the energy consumption for the production of hydrogen. The potential loss of SDE process could be separated into four components, i.e. reversible cell potential, anode overpotential, cathode overpotential and ohmic loss. So far, it has been identified that the total cell potential for the SO_2 depolarized electrolyzer is dominantly controlled by sulfuric acid concentration of the anolyte and electrolysis temperature of the electrolysis process. In this work, an in-situ Electrochemical Impedance Spectroscopy (EIS) measurement of the anodic SDE reaction was conducted. Results show that anodic overpotential is mainly resulted from the SO_2 oxidation reaction other than ohmic resistance or mass transfer limitation. This study extends the understanding to SDE process and gives suggestions for the further improvement of the SDE performance. (author)

  5. Light depolarization induced by metallic tips in apertureless near-field optical microscopy and tip-enhanced Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gucciardi, P G [CNR-Istituto per i Processi Chimico-Fisici, sezione Messina, Salita Sperone, Contrada Papardo, I-98158 Faro Superiore, Messina (Italy); Lopes, M; Deturche, R; Julien, C; Barchiesi, D; Chapelle, M Lamy de la [Institut Charles Delaunay-CNRS FRE 2848, Laboratoire de Nanotechnologie et d' Instrumentation Optique, Universite de Technologie de Troyes, 12 rue Marie Curie, BP2060, 10010 Troyes (France)


    We have investigated the depolarization effects of light scattered by sharp tips used for apertureless near-field optical microscopy. Dielectric and metal coated tips have been investigated and depolarization factors between 5 and 30% have been measured, changing as a function of the incident light polarization and of the tip shape. The experimental results are in good agreement with theoretical calculations performed by the finite element method, giving a near-field depolarization factor close to 10%. The effect of depolarization has been investigated in polarized tip-enhanced Raman spectroscopy (TERS) experiments; the depolarization gives rise to forbidden Raman modes in Si crystals.

  6. Mechanisms underlying the benefits of anticonvulsants over lithium in the treatment of bipolar disorder. (United States)

    Corrado, Alisa C; Walsh, John P


    Close to 3% of the world's population suffers from bipolar disease (I and II). Of this 3%, bipolar disease affects largely women (∼ 3 : 2 compared with men). The median age of diagnosis is 25 in women and even lower in men. A diagnosis of bipolar disease is an expensive psychiatric diagnosis, costing patients more than twice as much money as a diagnosis of unipolar depression. Bipolar I is characterized by one or more manic or mixed episodes, with both mania and depression occurring each day for at least 1 week, whereas bipolar II is characterized by one or more major depressive episode and at least one episode of hypomania. Bipolar I is the more severe diagnosis. A wide range of medications are available to help patients maintain a healthy lifestyle, including lithium, antidepressants, and anticonvulsants. Improved methods for identifying bipolar disease, including a more structured approach and a more complete use of medical records, have increased the rate of diagnosis, especially in children, which underscores the need for innovation in development and in practice of new treatment options for treating bipolar disease. Although lithium has been the 'gold standard' for treating bipolar disorder for decades, new research into other forms of treatment has shown anticonvulsants to be a particularly useful therapy for treating bipolar disease. Anticonvulsants have remarkable mood-stabilization abilities and they do not lead to serious side effects, which increases the tolerability, and consequently, patient adherence to this form of treatment. Recent studies have shown that anticonvulsants improve behavior in bipolar disease by modulating the balance of excitatory and inhibitory synapses through a number of complementary molecular cascades that affect gene expression and cell survival.

  7. Preliminary evidence that ketamine inhibits spreading depolarizations in acute human brain injury

    DEFF Research Database (Denmark)

    Sakowitz, Oliver W; Kiening, Karl L; Krajewski, Kara L


    by the noncompetitive N-methyl-d-aspartate receptor antagonist ketamine. This restored electrocorticographic activity. CONCLUSIONS: These anecdotal electrocorticographic findings suggest that ketamine has an inhibitory effect on spreading depolarizations in humans. This is of potential interest for future...

  8. Depolarization Rayleigh scattering as a means of molecular concentration determination in plasmas

    NARCIS (Netherlands)

    Meulenbroeks, R.F.G.; Schram, D.C.; Jaegers, L.J.M.; Sanden, van de M.C.M.


    The difference in polarization for Rayleigh scattered radiation on spherically and nonspherically symmetric scattering objects has been used to obtain molecular species concentrations in plasmas of simple composition. Using a Rayleigh scattering diagnostic, the depolarized component of the scattered

  9. Quetiapine monotherapy for bipolar depression

    Directory of Open Access Journals (Sweden)

    Michael E Thase


    Full Text Available Michael E ThaseDepartments of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, PA, USA; the Philadelphia Veterans Affairs Medical Center, Philadelphia, PA, USA; and the University of Pittsburgh Medical Center, Pittsburgh, PA, USAAbstract: Bipolar depression is more common, disabling, and difficult-to-treat than the manic and hypomanic phases that define bipolar disorder. Unlike the treatment of so-called “unipolar” depressions, antidepressants generally are not indicated as monotherapies for bipolar depressions and recent studies suggest that - even when used in combination with traditional mood stabilizers – antidepressants may have questionable value for bipolar depression. The current practice is that mood stabilizers are initiated first as monotherapies; however, the antidepressant efficacy of lithium and valproate is modest at best. Within this context the role of atypical antipsychotics is being evaluated. The combination of olanzapine and the antidepressant fluoxetine was the first treatment to receive regulatory approval in the US specifically for bipolar I depression. Quetiapine was the second medication to be approved for this indication, largely as the result of two pivotal trials known by the acronyms of BOLDER (BipOLar DEpRession I and II. Both studies demonstrated that two doses of quetiapine (300 mg and 600 mg given once daily at bedtime were significantly more effective than placebo, with no increased risk of patients switching into mania. Pooling the two studies, quetiapine was effective for both bipolar I and bipolar II depressions and for patients with (and without a history of rapid cycling. The two doses were comparably effective in both studies. Although the efficacy of quetiapine monotherapy has been established, much additional research is necessary. Further studies are needed to more fully investigate dose-response relationships and comparing quetiapine monotherapy to other mood stabilizers

  10. A review of depolarization modeling for earth-space radio paths at frequencies above 10 GHz (United States)

    Bostian, C. W.; Stutzman, W. L.; Gaines, J. M.


    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.

  11. Dibucaine mitigates spreading depolarization in human neocortical slices and prevents acute dendritic injury in the ischemic rodent neocortex.

    Directory of Open Access Journals (Sweden)

    W Christopher Risher

    Full Text Available Spreading depolarizations that occur in patients with malignant stroke, subarachnoid/intracranial hemorrhage, and traumatic brain injury are known to facilitate neuronal damage in metabolically compromised brain tissue. The dramatic failure of brain ion homeostasis caused by propagating spreading depolarizations results in neuronal and astroglial swelling. In essence, swelling is the initial response and a sign of the acute neuronal injury that follows if energy deprivation is maintained. Choosing spreading depolarizations as a target for therapeutic intervention, we have used human brain slices and in vivo real-time two-photon laser scanning microscopy in the mouse neocortex to study potentially useful therapeutics against spreading depolarization-induced injury.We have shown that anoxic or terminal depolarization, a spreading depolarization wave ignited in the ischemic core where neurons cannot repolarize, can be evoked in human slices from pediatric brains during simulated ischemia induced by oxygen/glucose deprivation or by exposure to ouabain. Changes in light transmittance (LT tracked terminal depolarization in time and space. Though spreading depolarizations are notoriously difficult to block, terminal depolarization onset was delayed by dibucaine, a local amide anesthetic and sodium channel blocker. Remarkably, the occurrence of ouabain-induced terminal depolarization was delayed at a concentration of 1 µM that preserves synaptic function. Moreover, in vivo two-photon imaging in the penumbra revealed that, though spreading depolarizations did still occur, spreading depolarization-induced dendritic injury was inhibited by dibucaine administered intravenously at 2.5 mg/kg in a mouse stroke model.Dibucaine mitigated the effects of spreading depolarization at a concentration that could be well-tolerated therapeutically. Hence, dibucaine is a promising candidate to protect the brain from ischemic injury with an approach that does not rely on

  12. Integrated neurobiology of bipolar disorder

    Directory of Open Access Journals (Sweden)

    Vladimir eMaletic


    Full Text Available From a neurobiological perspective there is no such thing as bipolar disorder. Rather, it is almost certainly the case that many somewhat similar, but subtly different, pathological conditions produce a disease state that we currently diagnose as bipolarity. This heterogeneity—reflected in the lack of synergy between our current diagnostic schema and our rapidly advancing scientific understanding of the condition—limits attempts to articulate an integrated perspective on bipolar disorder. However, despite these challenges, scientific findings in recent years are beginning to offer a provisional unified field theory of the disease. This theory sees bipolar disorder as a suite of related neurodevelopmental conditions with interconnected functional abnormalities that often appear early in life and worsen over time. In addition to accelerated loss of volume in brain areas known to be essential for mood regulation and cognitive function, consistent findings have emerged at a cellular level, providing evidence that bipolar disorder is reliably associated with dysregulation of glial-neuronal interactions. Among these glial elements are microglia—the brain’s primary immune elements, which appear to be overactive in the context of bipolarity. Multiple studies now indicate that inflammation is also increased in the periphery of the body in both the depressive and manic phases of the illness, with at least some return to normality in the euthymic state. These findings are consistent with changes in the HPA axis, which are known to drive inflammatory activation. In summary, the very fact that no single gene, pathway or brain abnormality is likely to ever account for the condition is itself an extremely important first step in better articulating an integrated perspective on both its ontological status and pathogenesis. Whether this perspective will translate into the discovery of innumerable more homogeneous forms of bipolarity is one of the great

  13. Bipolar Disorder and Alcoholism: Are They Related? (United States)

    ... Are they related? Is there a connection between bipolar disorder and alcoholism? Answers from Daniel K. Hall-Flavin, M.D. Bipolar disorder and alcoholism often occur together. Although the association ...

  14. Bipolar outflow in B335

    International Nuclear Information System (INIS)

    Hirano, N.; Kameya, O.; Nakayama, M.; Takakubo, K.


    The high-velocity (C-12)O (J = 1-0) emission in B335 with a high angular resolution of 16 arcsec has been mapped. The high-velocity emission shows distinct bipolar pattern centered at IRAS 19345+0727, toward which a strong high-velocity (C-12)O emission has been detected. The bipolar lobes delineate remarkable collimation toward the IRAS source, indicating that the flow is focused within 0.02 pc of the driving source. Each lobe is accompanied by significant wing emission with the opposite velocity shift, which clearly shows the association with IRAS 19345+0727. This feature is well explained as a bipolar flow the axis of which is nearly perpendicular to the line of sight. There is no evidence of another evolved bipolar flow which does not associate with any dense core as previously suggested. This suggests that B335 is a site of very recent star formation, containing a single bipolar flow with an age of about 30,000 yr. 15 references

  15. Exercising control over bipolar disorder. (United States)

    Malhi, Gin S; Byrow, Yulisha


    Following extensive research exercise has emerged as an effective treatment for major depressive disorder, and it is now a recognised therapy alongside other interventions. In contrast, there is a paucity of research examining the therapeutic effects of exercise for those with bipolar disorder. Given that dysfunctional reward processing is central to bipolar disorder, research suggests that exercise can perhaps be framed as a reward-related event that may have the potential to precipitate a manic episode. The behavioural activation system (BAS) is a neurobehavioural system that is associated with responding to reward and provides an appropriate framework to theoretically examine and better understand the effects of exercise treatment on bipolar disorder. This article discusses recent research findings and provides an overview of the extant literature related to the neurobiological underpinnings of BAS and exercise as they relate to bipolar disorder. This is important clinically because depending on mood state in bipolar disorder, we postulate that exercise could be either beneficial or deleterious with positive or negative effects on the illness. Clearly, this complicates the evaluation of exercise as a potential treatment in terms of identifying its optimal characteristics in this population. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to

  16. The depolarizing action of GABA in cultured hippocampal neurons is not due to the absence of ketone bodies. (United States)

    Waddell, Jaylyn; Kim, Jimok; Alger, Bradley E; McCarthy, Margaret M


    Two recent reports propose that the depolarizing action of GABA in the immature brain is an artifact of in vitro preparations in which glucose is the only energy source. The authors argue that this does not mimic the physiological environment because the suckling rats use ketone bodies and pyruvate as major sources of metabolic energy. Here, we show that availability of physiologically relevant levels of ketone bodies has no impact on the excitatory action of GABA in immature cultured hippocampal neurons. Addition of β-hydroxybutyrate (BHB), the primary ketone body in the neonate rat, affected neither intracellular calcium elevation nor membrane depolarizations induced by the GABA-A receptor agonist muscimol, when assessed with calcium imaging or perforated patch-clamp recording, respectively. These results confirm that the addition of ketone bodies to the extracellular environment to mimic conditions in the neonatal brain does not reverse the chloride gradient and therefore render GABA hyperpolarizing. Our data are consistent with the existence of a genuine "developmental switch" mechanism in which GABA goes from having a predominantly excitatory role in immature cells to a predominantly inhibitory one in adults.

  17. Late Onset Bipolar Disorder: Case Report


    Filipa Araújo; Adriana Horta


    Background: Bipolar disorder affects approximately 1% of the population, with diagnosis often being made during late adolescence and early adulthood, and only rarely (0.1%) in the elderly. Late onset bipolar disorder in the elderly has a impact on the nature and course of bipolar disorder. Aims: The authors report a case of bipolar disorder emerging in late life  (76years old) with no cleary identified organic cause. Conclusion: This case highlights the importance of a broad different...

  18. Imunologia do transtorno bipolar Immunology of bipolar disorder

    Directory of Open Access Journals (Sweden)

    Izabela Guimarães Barbosa


    Full Text Available OBJETIVO: Pesquisas recentes têm implicado fatores imunes na patogênese de diversos transtornos neuropsiquiátricos. O objetivo do presente trabalho é revisar os trabalhos que investigaram a associação entre transtorno bipolar e alterações em parâmetros imunes. MÉTODOS: Artigos que incluíam as palavras-chave: "bipolar disorder", "mania", "immunology", "cytokines", "chemokines", "interleukins", "interferon" e "tumor necrosis factor" foram selecionados em uma revisão sistemática da literatura. As bases de dados avaliadas foram MedLine e Scopus, entre os anos de 1980 e 2008. RESULTADOS: Foram identificados 28 trabalhos que estudaram alterações imunes em pacientes com transtorno bipolar. Seis artigos investigaram genes relacionados à resposta imune; cinco, autoanticorpos; quatro, populações leucocitárias; 13, citocinas e/ou moléculas relacionadas à resposta imune e seis, leucócitos de pacientes in vitro. CONCLUSÕES: Embora haja evidências na literatura correlacionando o transtorno bipolar a alterações imunes, os dados não são conclusivos. O transtorno bipolar parece estar associado a níveis mais elevados de autoanticorpos circulantes, assim como à tendência à ativação imune com produção de citocinas pró-inflamatórias e redução de parâmetros anti-inflamatórios.OBJECTIVE: Emerging research has implicated immune factors in the pathogenesis of a variety of neuropsychiatric disorders. The objective of the present paper is to review the studies that investigated the association between bipolar disorder and immune parameters. METHODS: Papers that included the keywords "bipolar to disorder", "mania", "immunology", "cytokines", "chemokines", "interleukins", "interferon" and "tumor necrosis factor" were selected in a systematic review of the literature. The evaluated databases were MedLine and Scopus in the period between 1980 and 2008. RESULTS: Twenty eight works were found. Six studies investigated immune response

  19. Tritium isotope separation from light and heavy water by bipolar electrolysis

    International Nuclear Information System (INIS)

    Petek, M.; Ramey, D.W.; Taylor, R.D.; Kobisk, E.H.


    A process for separating tritium from light and heavy water is described. Hydrogen is transferred at and through bipolar electrodes at rates H > D > T. In a cell containing several bipolar electrodes placed in series between two terminal electrodes, a flow of hydrogen is established from the terminal anode compartment toward the terminal cathode. An electrolyte feed containing tritium is continuously added to the system and is subsequently transported countercurrent to the hydrogen mass transfer. A cascaded system is established, in which effluent streams enriched and depleted in tritium can be withdrawn. The voltage drop is smaller at any bipolar electrode as compared to the voltage for normal electrolysis. Cell design is compact because isotope separation occurs at bipolar electrodes without evolution of gas. Isotope separation was demonstrated in laboratory cells where a steady-state tritium concentration gradient was attained. This gradient was in agreement with concentrations calculated from a derived mathematical model

  20. The role of glutamate in neuronal ion homeostasis: A case study of spreading depolarization.

    Directory of Open Access Journals (Sweden)

    Niklas Hübel


    Full Text Available Simultaneous changes in ion concentrations, glutamate, and cell volume together with exchange of matter between cell network and vasculature are ubiquitous in numerous brain pathologies. A complete understanding of pathological conditions as well as normal brain function, therefore, hinges on elucidating the molecular and cellular pathways involved in these mostly interdependent variations. In this paper, we develop the first computational framework that combines the Hodgkin-Huxley type spiking dynamics, dynamic ion concentrations and glutamate homeostasis, neuronal and astroglial volume changes, and ion exchange with vasculature into a comprehensive model to elucidate the role of glutamate uptake in the dynamics of spreading depolarization (SD-the electrophysiological event underlying numerous pathologies including migraine, ischemic stroke, aneurysmal subarachnoid hemorrhage, intracerebral hematoma, and trauma. We are particularly interested in investigating the role of glutamate in the duration and termination of SD caused by K+ perfusion and oxygen-glucose deprivation. Our results demonstrate that glutamate signaling plays a key role in the dynamics of SD, and that impaired glutamate uptake leads to recovery failure of neurons from SD. We confirm predictions from our model experimentally by showing that inhibiting astrocytic glutamate uptake using TFB-TBOA nearly quadruples the duration of SD in layers 2-3 of visual cortical slices from juvenile rats. The model equations are either derived purely from first physical principles of electroneutrality, osmosis, and conservation of particles or a combination of these principles and known physiological facts. Accordingly, we claim that our approach can be used as a future guide to investigate the role of glutamate, ion concentrations, and dynamics cell volume in other brain pathologies and normal brain function.

  1. The role of glutamate in neuronal ion homeostasis: A case study of spreading depolarization. (United States)

    Hübel, Niklas; Hosseini-Zare, Mahshid S; Žiburkus, Jokūbas; Ullah, Ghanim


    Simultaneous changes in ion concentrations, glutamate, and cell volume together with exchange of matter between cell network and vasculature are ubiquitous in numerous brain pathologies. A complete understanding of pathological conditions as well as normal brain function, therefore, hinges on elucidating the molecular and cellular pathways involved in these mostly interdependent variations. In this paper, we develop the first computational framework that combines the Hodgkin-Huxley type spiking dynamics, dynamic ion concentrations and glutamate homeostasis, neuronal and astroglial volume changes, and ion exchange with vasculature into a comprehensive model to elucidate the role of glutamate uptake in the dynamics of spreading depolarization (SD)-the electrophysiological event underlying numerous pathologies including migraine, ischemic stroke, aneurysmal subarachnoid hemorrhage, intracerebral hematoma, and trauma. We are particularly interested in investigating the role of glutamate in the duration and termination of SD caused by K+ perfusion and oxygen-glucose deprivation. Our results demonstrate that glutamate signaling plays a key role in the dynamics of SD, and that impaired glutamate uptake leads to recovery failure of neurons from SD. We confirm predictions from our model experimentally by showing that inhibiting astrocytic glutamate uptake using TFB-TBOA nearly quadruples the duration of SD in layers 2-3 of visual cortical slices from juvenile rats. The model equations are either derived purely from first physical principles of electroneutrality, osmosis, and conservation of particles or a combination of these principles and known physiological facts. Accordingly, we claim that our approach can be used as a future guide to investigate the role of glutamate, ion concentrations, and dynamics cell volume in other brain pathologies and normal brain function.

  2. Mathematical models of bipolar disorder (United States)

    Daugherty, Darryl; Roque-Urrea, Tairi; Urrea-Roque, John; Troyer, Jessica; Wirkus, Stephen; Porter, Mason A.


    We use limit cycle oscillators to model bipolar II disorder, which is characterized by alternating hypomanic and depressive episodes and afflicts about 1% of the United States adult population. We consider two non-linear oscillator models of a single bipolar patient. In both frameworks, we begin with an untreated individual and examine the mathematical effects and resulting biological consequences of treatment. We also briefly consider the dynamics of interacting bipolar II individuals using weakly-coupled, weakly-damped harmonic oscillators. We discuss how the proposed models can be used as a framework for refined models that incorporate additional biological data. We conclude with a discussion of possible generalizations of our work, as there are several biologically-motivated extensions that can be readily incorporated into the series of models presented here.

  3. Is bipolar always bipolar? Understanding the controversy on bipolar disorder in children (United States)

    Grimmer, Yvonne; Hohmann, Sarah


    Dramatically increasing prevalence rates of bipolar disorder in children and adolescents in the United States have provoked controversy regarding the boundaries of manic symptoms in child and adolescent psychiatry. The serious impact of this ongoing debate on the treatment of affected children is reflected in the concomitant increase in prescription rates for antipsychotic medication. A key question in the debate is whether this increase in bipolar disorder in children and adolescents is based on a better detection of early-onset bipolar disorder—which can present differently in children and adolescents—or whether it is caused by an incorrect assignment of symptoms which overlap with other widely known disorders. So far, most findings suggest that the suspected symptoms, in particular chronic, non-episodic irritability (a mood symptom presenting with easy annoyance, temper tantrums and anger) do not constitute a developmental presentation of childhood bipolar disorder. Additional research based on prospective, longitudinal studies is needed to further clarify the developmental trajectories of bipolar disorder and the diagnostic status of chronic, non-episodic irritability. PMID:25580265

  4. The second phase of bipolar, nanosecond-range electric pulses determines the electroporation efficiency. (United States)

    Pakhomov, Andrei G; Grigoryev, Sergey; Semenov, Iurii; Casciola, Maura; Jiang, Chunqi; Xiao, Shu


    Bipolar cancellation refers to a phenomenon when applying a second electric pulse reduces ("cancels") cell membrane damage by a preceding electric pulse of the opposite polarity. Bipolar cancellation is a reason why bipolar nanosecond electric pulses (nsEP) cause weaker electroporation than just a single unipolar phase of the same pulse. This study was undertaken to explore the dependence of bipolar cancellation on nsEP parameters, with emphasis on the amplitude ratio of two opposite polarity phases of a bipolar pulse. Individual cells (CHO, U937, or adult mouse ventricular cardiomyocytes (VCM)) were exposed to either uni- or bipolar trapezoidal nsEP, or to nanosecond electric field oscillations (NEFO). The membrane injury was evaluated by time-lapse confocal imaging of the uptake of propidium (Pr) or YO-PRO-1 (YP) dyes and by phosphatidylserine (PS) externalization. Within studied limits, bipolar cancellation showed little or no dependence on the electric field intensity, pulse repetition rate, chosen endpoint, or cell type. However, cancellation could increase for larger pulse numbers and/or for longer pulses. The sole most critical parameter which determines bipolar cancellation was the phase ratio: maximum cancellation was observed with the 2nd phase of about 50% of the first one, whereas a larger 2nd phase could add a damaging effect of its own. "Swapping" the two phases, i.e., delivering the smaller phase before the larger one, reduced or eliminated cancellation. These findings are discussed in the context of hypothetical mechanisms of bipolar cancellation and electroporation by nsEP. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Application of bipolar electrodialysis to E.coli fermentation for simultaneous acetate removal and pH control

    DEFF Research Database (Denmark)

    Wong, M.; Woodley, John; Lye, G.J.


    The application of bipolar electrodialysis (BPED) for the simultaneous removal of inhibitory acetate and pH control during E. coli fermentation was investigated. A two cell pair electrodialysis module, consisting of cation exchange, anion exchange and bipolar membranes with working area of 100 cm2...

  6. Bipolar dislocation of the clavicle

    Directory of Open Access Journals (Sweden)

    Wei Jiang


    Full Text Available Bipolar dislocation of the clavicle at acromioclavicular and sternoclavicular joint is an uncommon traumatic injury. The conservative treatments adopted in the past is associated with redislocation dysfunction and deformity. A 41 years old lady with bipolar dislocation of right shoulder is treated surgically by open reduction and internal fixation by oblique T-plate at sternoclavicular joint and Kirschner wire stabilization at acromioclavicular joint. The patient showed satisfactory recovery with full range of motion of the right shoulder and normal muscular strength. The case reported in view of rarity and at 2 years followup.

  7. Transcultural aspects of bipolar disorder


    Sanches, Marsal; Jorge, Miguel Roberto


    Considerando-se que existem diferenças importantes na maneira como as emoções são vivenciadas e expressas em diferentes culturas, a apresentação e o manejo do transtorno afetivo bipolar sofrem influência de fatores culturais. O presente artigo realiza uma breve revisão da evidência referente aos aspectos transculturais do transtorno bipolar.Cultural variations in the expression of emotions have been described. Consequently, there are cross-cultural influences on the diagnosis and management o...

  8. A composite peripheral blood gene expression measure as a potential diagnostic biomarker in bipolar disorder

    DEFF Research Database (Denmark)

    Munkholm, Klaus; Peijs, L; Vinberg, M


    as a diagnostic and state biomarker in bipolar disorder. First, messenger RNA levels of 19 candidate genes were assessed in peripheral blood mononuclear cells of 37 rapid cycling bipolar disorder patients in different affective states (depression, mania and euthymia) during a 6-12-month period and in 40 age...... subjects. In patients with bipolar disorder, upregulation of NDUFV2 was observed in a depressed state compared with a euthymic state. The composite gene expression measure for discrimination between patients and healthy control subjects on the basis of 19 genes generated an area under the receiver...

  9. Characterization of ventricular depolarization and repolarization changes in a porcine model of myocardial infarction. (United States)

    Romero, Daniel; Ringborn, Michael; Demidova, Marina; Koul, Sasha; Laguna, Pablo; Platonov, Pyotr G; Pueyo, Esther


    In this study, several electrocardiogram (ECG)-derived indices corresponding to both ventricular depolarization and repolarization were evaluated during acute myocardial ischemia in an experimental model of myocardial infarction produced by 40 min coronary balloon inflation in 13 pigs. Significant changes were rapidly observed from minute 4 after the start of coronary occlusion, achieving their maximum values between 11 and 22 min for depolarization and between 9 and 12 min for repolarization indices, respectively. Subsequently, these maximum changes started to decrease during the latter part of the occlusion. Depolarization changes associated with the second half of the QRS complex showed a significant but inverse correlation with the myocardium at risk (MaR) estimated by scintigraphic images. The correlation between MaR and changes of the downward slope of the QRS complex, [Formula: see text], evaluated at the two more relevant peaks observed during the occlusion, was r = -0.75, p evolution, respectively. Repolarization changes, analyzed by evaluation of ST segment elevation at the main observed positive peak, also showed negative, however non-significant correlation with MaR: r = -0.34, p = 0.28. Our results suggest that changes evaluated in the latter part of the depolarization, such as those described by [Formula: see text], which are influenced by R-wave amplitude, QRS width and ST level variations simultaneously, correlate better with the amount of ischemia than other indices evaluated in the earlier part of depolarization or during the ST segment.

  10. Development of materials and processes for low-cost production of high-temperature bipolar plates for use in polymer electrolyte membrane fuel cells (PEMFC). Final report; Material- und Verfahrensentwicklung fuer eine kostenguenstige Herstellung von Hochtemperatur-Bipolarplatten zum Einsatz in Polymer-Elektrolyt-Membran Brennstoffzellen (PEM-BZ). Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)



    In the context of the project 'Verfahren zur spritzgiesstechnischen Herstellung von HT-BPP' (processes for injection moulding of high-temperature fuel cells), bipolar plates for high-temperature proton exchange membrane fuel cells (HT-PEM-FC) were produced by an injection moulding process suited for mass production. This implied extensive material analyses of fillers and matrix materials. A specific compound for application in fuel cells and suited for mass production was produced on this basis. (orig./AKB)

  11. Social support and bipolar disorder

    Directory of Open Access Journals (Sweden)

    Paula Mendonça Studart


    Full Text Available Background Bipolar disorder is a chronic condition that affects the functioning of its carriers in many different ways, even when treated properly. Therefore, it’s also important to identify the psychosocial aspects that could contribute to an improvement of this population’s quality of life.Objective Carry out a literature review on the role of social support in cases of bipolar disorder.Method A research on the following online databases PubMed, Lilacs and SciELO was conducted by using the keywords “social support” or “social networks” and “mood disorders” or “bipolar disorder” or “affective disorder,” with no defined timeline.Results Only 13 studies concerning the topic of social support and BD were found in the search for related articles. Generally speaking, the results show low rates of social support for BD patients.Discussion Despite the growing interest in the overall functioning of patients with bipolar disorder, studies on social support are still rare. Besides, the existing studies on the subject use different methodologies, making it difficult to establish data comparisons.

  12. Integrated Neurobiology of Bipolar Disorder (United States)

    Maletic, Vladimir; Raison, Charles


    From a neurobiological perspective there is no such thing as bipolar disorder. Rather, it is almost certainly the case that many somewhat similar, but subtly different, pathological conditions produce a disease state that we currently diagnose as bipolarity. This heterogeneity – reflected in the lack of synergy between our current diagnostic schema and our rapidly advancing scientific understanding of the condition – limits attempts to articulate an integrated perspective on bipolar disorder. However, despite these challenges, scientific findings in recent years are beginning to offer a provisional “unified field theory” of the disease. This theory sees bipolar disorder as a suite of related neurodevelopmental conditions with interconnected functional abnormalities that often appear early in life and worsen over time. In addition to accelerated loss of volume in brain areas known to be essential for mood regulation and cognitive function, consistent findings have emerged at a cellular level, providing evidence that bipolar disorder is reliably associated with dysregulation of glial–neuronal interactions. Among these glial elements are microglia – the brain’s primary immune elements, which appear to be overactive in the context of bipolarity. Multiple studies now indicate that inflammation is also increased in the periphery of the body in both the depressive and manic phases of the illness, with at least some return to normality in the euthymic state. These findings are consistent with changes in the hypothalamic–pituitary–adrenal axis, which are known to drive inflammatory activation. In summary, the very fact that no single gene, pathway, or brain abnormality is likely to ever account for the condition is itself an extremely important first step in better articulating an integrated perspective on both its ontological status and pathogenesis. Whether this perspective will translate into the discovery of innumerable more homogeneous forms of

  13. Electropermeabilization by uni- or bipolar nanosecond electric pulses: The impact of extracellular conductivity. (United States)

    Gianulis, Elena C; Casciola, Maura; Xiao, Shu; Pakhomova, Olga N; Pakhomov, Andrei G


    Cellular effects caused by nanosecond electric pulses (nsEP) can be reduced by an electric field reversal, a phenomenon known as bipolar cancellation. The reason for this cancellation effect remains unknown. We hypothesized that assisted membrane discharge is the mechanism for bipolar cancellation. CHO-K1 cells bathed in high (16.1mS/cm; HCS) or low (1.8mS/cm; LCS) conductivity solutions were exposed to either one unipolar (300-ns) or two opposite polarity (300+300-ns; bipolar) nsEP (4-40kV/cm) with increasing interpulse intervals (0.1-50μs). Time-lapse YO-PRO-1 (YP) uptake revealed enhanced membrane permeabilization in LCS compared to HCS at all tested voltages. The time-dependence of bipolar cancellation was similar in both solutions, using either identical (22kV/cm) or isoeffective nsEP treatments (12 and 32kV/cm for LCS and HCS, respectively). However, cancellation was significantly stronger in LCS when the bipolar nsEP had no, or very short (bipolar cancellation was still present with interpulse intervals as long as 50μs, beyond the time expected for membrane discharge. Our findings do not support assisted membrane discharge as the mechanism for bipolar cancellation. Instead they exemplify the sustained action of nsEP that can be reversed long after the initial stimulus. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Currents of thermally stimulated depolarization in CaIn2S4 single crystals

    International Nuclear Information System (INIS)

    Tagiev, B.G.; Tagiev, O.B.; Dzhabbarov, R.B.; Musaeva, N.N.


    The results of investigation into currents of thermally stimulated depolarization in CaIn 2 S 4 monocrystals are presented for the first time. Spectra of thermally stimulated depolarization for In-CaIn S4 -In structures are measured under T=99 K at various rates of heat, times of polarization and times of expectation following switching off of electrical field up to beginning of measurements of shorting. The main parameters of capture cross section, partial factor, concentration of traps, are determined. It is determined that one may observed a biomolecular mechanism with a strong secondary capture in CaIn 2 S 4 monocrystals. 9 refs.; 4 figs

  15. A stochastic model of depolarization enhancement due to large energy spread in electron storage rings

    International Nuclear Information System (INIS)

    Buon, J.


    A new semiclassical and stochastic model of spin diffusion is used to obtain numerical predictions for depolarization enhancement due to beam energy spread. It confirms the results of previous models for the synchrotron sidebands of isolated spin resonances. A satisfactory agreement is obtained with the width of a synchrotron satellite observed at SPEAR. For HERA and LEP, at Z 0 energy, the depolarization enhancement is of the order of a few units and increases very rapidly with the energy spread. Large reduction of polarization degree is expected in these rings

  16. Analytic calculation of depolarization due to large energy spread in high-energy electron storage rings

    International Nuclear Information System (INIS)

    Buon, J.


    A new semiclassical and stochastic model of spin diffusion is used to obtain numerical predictions for depolarization enhancement due to beam energy spread. It confirms the results of previous models for the synchrotron sidebands of spin resonances. A satisfactory agreement is obtained with the width of a synchrotron satellite observed at SPEAR. For HERA, TRISTAN, and LEP at Z 0 energy, the depolarization enhancement is of the order of a few units and increases very rapidly with the energy spread. Large reduction of polarization degree is expected in these rings

  17. Beam depolarization and gain saturation in neodymium rods with a diameter of 85 mm

    Energy Technology Data Exchange (ETDEWEB)

    Sukhanov, V N; Ugodenko, A A


    Depolarization and gain saturation were investigated in rod amplifiers using phosphate and silicate Nd glasses 85 mm in diameter and 300 mm in length at a pulse duration of 35 ns. Total depolarization losses over the rod cross section were measured for various radial distributions of the small-signal gain. For the phosphate glass the losses amounted to 3-6 percent; for the silicate glass, they amounted to 4-7 percent. Saturation energy densities of 4.5 + or - 0.4 and 8.0 + or - 0.7 J/sq cm were obtained for the phosphate and silicate glass, respectively. 8 refs.

  18. Detection of spreading depolarization with intraparenchymal electrodes in the injured human brain

    DEFF Research Database (Denmark)

    Jeffcote, Toby; Hinzman, Jason M; Jewell, Sharon L


    be detected using intra-cortical electrodes, opening the way for electrode insertion via burr hole. METHODS: Animal work was carried out on adult Sprague-Dawley rats in a laboratory setting to investigate the feasibility of recording depolarization events. Subsequently, 8 human patients requiring craniotomy...... for craniotomy. The method provides a new investigative tool for the evaluation of the contribution of these events to secondary brain injury in human patients.......BACKGROUND: Spreading depolarization events following ischemic and traumatic brain injury are associated with poor patient outcome. Currently, monitoring these events is limited to patients in whom subdural electrodes can be placed at open craniotomy. This study examined whether these events can...

  19. Measurement of the depolarization rate of positive muons in copper and aluminium

    International Nuclear Information System (INIS)

    Gauster, W.B.; Heffner, R.H.; Huang, C.Y.; Hutson, R.L.; Leon, M.; Parkin, D.M.; Schillaci, M.E.; Triftshaeuser, W.; Wampler, W.R.


    Positive muon spin rotation experiments for polycrystalline Cu and Al from 19 K to temperatures near the melting points are reported. At low temperatures, the depolarization associated with localization of the muons at octahedral interstitial sites is seen in Cu, while in Al only slight depolarization is observed below 250 K. At high temperatures, no evidence for trapping of positive muons at vacancies in thermal equilibrium is found for either metal. It is concluded that the muons either diffuse too slowly to find vacancies or, if they do find vacancies, are bound too weakly to remain trapped. (author)

  20. Depolarization and electrical stimulation enhance in vitro and in vivo sensory axon growth after spinal cord injury. (United States)

    Goganau, Ioana; Sandner, Beatrice; Weidner, Norbert; Fouad, Karim; Blesch, Armin


    Activity dependent plasticity is a key mechanism for the central nervous system (CNS) to adapt to its environment. Whether neuronal activity also influences axonal regeneration in the injured CNS, and whether electrical stimulation (ES) can activate regenerative programs in the injured CNS remains incompletely understood. Using KCl-induced depolarization, in vivo ES followed by ex-vivo neurite growth assays and ES after spinal cord lesions and cell grafting, we aimed to identify parameters important for ES-enhanced neurite growth and axonal regeneration. Using cultures of sensory neurons, neurite growth was analyzed after KCl-induced depolarization for 1-72h. Increased neurite growth was detected after short-term stimulation and after longer stimulation if a sufficient delay between stimulation and growth measurements was provided. After in vivo ES (20Hz, 2× motor threshold, 0.2ms, 1h) of the intact sciatic nerve in adult Fischer344 rats, sensory neurons showed a 2-fold increase in in vitro neurite length one week later compared to sham animals, an effect not observed one day after ES. Longer ES (7h) and repeated ES (7days, 1h each) also increased growth by 56-67% one week later, but provided no additional benefit. In vivo growth of dorsal column sensory axons into a graft of bone marrow stromal cells 4weeks after a cervical spinal cord lesion was also enhanced with a single post-injury 1h ES of the intact sciatic nerve and was also observed after repeated ES without inducing pain-like behavior. While ES did not result in sensory functional recovery, our data indicate that ES has time-dependent influences on the regenerative capacity of sensory neurons and might further enhance axonal regeneration in combinatorial approaches after SCI. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Evaluation of the impact of two flow field designs with bipolar plate flow on the performance of a PEM fuel cell; Evaluacion del impacto de dos disenos de campo de flujo de placa bipolar en el desempeno de una celda de combustible tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Loyola-Morales, F.; Cano-Castillo, U. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail:


    The flow field (FF) designs of bipolar plates play a fundamental role in the performance of a set of PEM fuel cells. The FF is directly related with diverse processes that occur inside the cells, such as: feeding and uniform distribution of reactant gases and the handling of water produced by the overall electrochemical reaction. Therefore, a FF design that promotes each one of those processes in an optimal manner is of utmost importance to attain the best performance of a set of fuel cells. The present work evaluated the impact of two different FF on the performance of a fuel cell. The FF designs evaluated were 4 serpentine and parallels (4SP) and 2 serpentine counter flow (SC). The stability tests for the operation of the cell applied to each of the flow fields were: flood tolerance, dehydration tolerance conditions and stoichiometry performance of 1.1, 1.3, 1.5 and 2.5. The 4SP design showed high performance stability during operation with a gradual process of flooding the system and operating at different stoichiometries. Only for the test with dehydration conditions was there a gradual decrease in its performance, of up to 27%. Compared to these results, the SC design showed a rapid fall of 45% in its performance when operating under gradual flooding of the system, a constant fall in its performance (also around 45%) with stoichiometries of 1.1, 1.3 and 1.5 due to accumulation of water, and only with a stoichiometry of 2.5 did it have highly stable performance as a result of good water handling. In the test of operations under dehydration conditions, the performance of the SC design dropped to 40% and remained at this value during the rest of the test. According to these results, the performance of the 4SP design was more stable than the SC design for all of the tests implemented. [Spanish] Los disenos de campo de flujo (CF) de las placas bipolares tienen un papel fundamental en el desempeno de un conjunto de celdas de combustible tipo PEM. Los CF tienen una

  2. CRY2 is associated with rapid cycling in bipolar disorder patients.

    Directory of Open Access Journals (Sweden)

    Louise K Sjöholm


    Full Text Available Bipolar disorder patients often display abnormalities in circadian rhythm, and they are sensitive to irregular diurnal rhythms. CRY2 participates in the core clock that generates circadian rhythms. CRY2 mRNA expression in blood mononuclear cells was recently shown to display a marked diurnal variation and to respond to total sleep deprivation in healthy human volunteers. It was also shown that bipolar patients in a depressive state had lower CRY2 mRNA levels, nonresponsive to total sleep deprivation, compared to healthy controls, and that CRY2 gene variation was associated with winter depression in both Swedish and Finnish cohorts.Four CRY2 SNPs spanning from intron 2 to downstream 3'UTR were analyzed for association to bipolar disorder type 1 (n = 497, bipolar disorder type 2 (n = 60 and bipolar disorder with the feature rapid cycling (n = 155 versus blood donors (n = 1044 in Sweden. Also, the rapid cycling cases were compared with bipolar disorder cases without rapid cycling (n = 422. The haplotype GGAC was underrepresented among rapid cycling cases versus controls and versus bipolar disorder cases without rapid cycling (OR = 0.7, P = 0.006-0.02, whereas overrepresentation among rapid cycling cases was seen for AAAC (OR = 1.3-1.4, P = 0.03-0.04 and AGGA (OR = 1.5, P = 0.05. The risk and protective CRY2 haplotypes and their effect sizes were similar to those recently suggested to be associated with winter depression in Swedes.We propose that the circadian gene CRY2 is associated with rapid cycling in bipolar disorder. This is the first time a clock gene is implicated in rapid cycling, and one of few findings showing a molecular discrimination between rapid cycling and other forms of bipolar disorder.

  3. Bipolar polygenic loading and bipolar spectrum features in major depressive disorder

    NARCIS (Netherlands)

    Wiste, Anna; Robinson, Elise B.; Milaneschi, Yuri; Meier, Sandra; Ripke, Stephan; Clements, Caitlin C.; Fitzmaurice, Garrett M.; Rietschel, Marcella; Penninx, Brenda W.; Smoller, Jordan W.; Perlis, Roy H.

    Objectives Family and genetic studies indicate overlapping liability for major depressive disorder and bipolar disorder. The purpose of the present study was to determine whether this shared genetic liability influences clinical presentation. Methods A polygenic risk score for bipolar disorder,

  4. Depolarization affects lateral microdomain structure of yeast plasma membrane

    Czech Academy of Sciences Publication Activity Database

    Herman, P.; Večeř, J.; Opekarová, Miroslava; Veselá, Petra; Jančíková, I.; Zahumenský, J.; Malínský, Jan


    Roč. 282, č. 3 (2015), s. 419-434 ISSN 1742-464X R&D Projects: GA ČR GAP205/12/0720 Institutional support: RVO:68378041 Keywords : gel microdomains * lipid order * transmembrane potential Subject RIV: EA - Cell Biology Impact factor: 4.237, year: 2015

  5. Neutron depolarization measurements of HoCo2 near the magnetic phase transition

    International Nuclear Information System (INIS)

    Kraan, W.


    The magnetic phase transition in HoCo 2 at zero applied field is investigated. The Landau theory of magnetic phase transition is discussed. The experimental technique for neutron depolarization measurements in the temperature range 65-90 K is described

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

    Energy Technology Data Exchange (ETDEWEB)

    Stone, Kevin H.


    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.

  7. Charge movement and depolarization-contraction coupling in arthropod vs. vertebrate skeletal muscle.


    Scheuer, T; Gilly, W F


    Voltage-dependent charge movement has been characterized in arthropod skeletal muscle. Charge movement in scorpion (Centuroides sculpturatus) muscle is distinguishable from that in vertebrate skeletal muscle by criteria of kinetics, voltage dependence, and pharmacology. The function of scorpion charge movement is gating of calcium channels in the sarcolemma, and depolarization-contraction coupling relies on calcium influx through these channels.

  8. Neutron depolarization study of static and dynamic magnetic properties of ferromagnets

    International Nuclear Information System (INIS)

    Stuesser, N.


    In this thesis neutron depolarization experiments are performed on amorphous and crystalline ferromagnetic materials. The subjects studied are concerned with 'domain structure in magnetically weak uniaxial amorphous ferromagnetic ribbons', 'static critical behaviour at the ferromagnetic-paramagnetic phase transition', 'small magnetic anisotropy in nickel near T c ', and 'magnetization reversal in conducting ferromagnets'. 87 refs.; 37 figs.; 3 tabs

  9. Depolarization-induced release of amino acids from the vestibular nuclear complex. (United States)

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


    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.

  10. Role of astrocytes in depolarization-coupled release of glutamate in cerebellar cultures

    DEFF Research Database (Denmark)

    Bak, Lasse K; Waagepetersen, Helle S; Schousboe, Arne


    Release of preloaded D-[3H]aspartate in response to depolarization induced by high potassium, N-methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) or the endogenous agonist glutamate was studied using cultured glutamatergic cerebellar granule neurons, cerebell...

  11. A new bipolar RRAM selector based on anti-parallel connected diodes for crossbar applications

    International Nuclear Information System (INIS)

    Li, Yingtao; Gong, Qingchun; Li, Rongrong; Jiang, Xinyu


    Crossbar arrays are the most promising application of a resistive random access memory (RRAM) device for achieving high density memory. However, cross-talk interference in the crossbar array limits the increase in the integration density. In this paper, the combination of two anti-parallel connected diodes and a bipolar RRAM cell is proposed to suppress the sneak current in a crossbar array with anti-parallel connected diodes as the selector for the bipolar RRAM. By using the anti-parallel connected diodes as a selector, the sneak current can be effectively suppressed and the high density crossbar array of more than 1 Mb can be realized as estimated by the 1/2V read voltage scheme. These results indicate that anti-parallel connected diodes can be used as a bipolar selector and have great potential for high density bipolar RRAM crossbar array applications. (papers)

  12. Bipolar one diode-one resistor integration for high-density resistive memory applications. (United States)

    Li, Yingtao; Lv, Hangbing; Liu, Qi; Long, Shibing; Wang, Ming; Xie, Hongwei; Zhang, Kangwei; Huo, Zongliang; Liu, Ming


    Different from conventional unipolar-type 1D-1R RRAM devices, a bipolar-type 1D-1R memory device concept is proposed and successfully demonstrated by the integration of Ni/TiOx/Ti diode and Pt/HfO2/Cu bipolar RRAM cell to suppress the undesired sneak current in a cross-point array. The bipolar 1D-1R memory device not only achieves self-compliance resistive switching characteristics by the reverse bias current of the Ni/TiOx/Ti diode, but also exhibits excellent bipolar resistive switching characteristics such as uniform switching, satisfactory data retention, and excellent scalability, which give it high potentiality for high-density integrated nonvolatile memory applications.

  13. Unsplit bipolar pulse forming line (United States)

    Rhodes, Mark A [Pleasanton, CA


    A bipolar pulse forming transmission line module and system for linear induction accelerators having first, second, third, and fourth planar conductors which form a sequentially arranged interleaved stack having opposing first and second ends, with dielectric layers between the conductors. The first and second planar conductors are connected to each other at the first end, and the first and fourth planar conductors are connected to each other at the second end via a shorting plate. The third planar conductor is electrically connectable to a high voltage source, and an internal switch functions to short at the first end a high voltage from the third planar conductor to the fourth planar conductor to produce a bipolar pulse at the acceleration axis with a zero net time integral. Improved access to the switch is enabled by an aperture through the shorting plate and the proximity of the aperture to the switch.

  14. Course of Subthreshold Bipolar Disorder in Youth: Diagnostic Progression from Bipolar Disorder Not Otherwise Specified (United States)

    Axelson, David A.; Birmaher, Boris; Strober, Michael A.; Goldstein, Benjamin I.; Ha, Wonho; Gill, Mary Kay; Goldstein, Tina R.; Yen, Shirley; Hower, Heather; Hunt, Jeffrey I.; Liao, Fangzi; Iyengar, Satish; Dickstein, Daniel; Kim, Eunice; Ryan, Neal D.; Frankel, Erica; Keller, Martin B.


    Objective: To determine the rate of diagnostic conversion from an operationalized diagnosis of bipolar disorder not otherwise specified (BP-NOS) to bipolar I disorder (BP-I) or bipolar II disorder (BP-II) in youth over prospective follow-up and to identify factors associated with conversion. Method: Subjects were 140 children and adolescents…

  15. Bipolar (spectrum) disorder and mood stabilization: standing at the crossroads?


    De Fruyt, Jurgen; Demyttenaere, Koen


    Diagnosis and treatment of bipolar disorder has long been a neglected discipline. Recent years have shown an upsurge in bipolar research. When compared to major depressive disorder, bipolar research still remains limited and more expert based than evidence based. In bipolar diagnosis the focus is shifting from classic mania to bipolar depression and hypomania. There is a search for bipolar signatures in symptoms and course of major depressive episodes. The criteria for hypomania are softened,...

  16. GABA sensitivity of spectrally classified horizontal cells in goldfish retina

    NARCIS (Netherlands)

    Verweij, J.; Kamermans, M.; Negishi, K.; Spekreijse, H.


    We studied the GABA sensitivity of horizontal cells in the isolated goldfish retina. After the glutamatergic input to the horizontal cells was blocked with DNQX, GABA depolarized the monophasic and biphasic horizontal cells. The pharmacology of these GABA-induced depolarizations was tested with the

  17. [Bipolar disorders in DSM-5]. (United States)

    Severus, E; Bauer, M


    In spring 2013 the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) edited by the American Psychiatric Association was published. The DSM-5 has also brought some important changes regarding bipolar disorders. The goal of this manuscript is to review the novelties in DSM-5 and to evaluate the implications of these changes. The diagnostic criteria as well as the additional remarks provided in the running text of DSM-5 were carefully appraised. For the first time diagnostic criteria are provided for disorders which up to now have been considered as subthreshold bipolar disorders. Furthermore, mixed episodes were eliminated and instead a mixed specifier was introduced. An increase in goal-directed activity/energy is now one of the obligatory symptoms for a (hypo)manic episode. Diagnostic guidance is provided as to when a (hypo)manic episode that has developed during treatment with an antidepressant has to be judged to be causally related to antidepressants and when this episode has only occurred coincidentally with antidepressant use. While some of the novelties are clearly useful, e.g. addition of increased goal-directed activity/energy as obligatory symptom for (hypo)manic episodes, this remains to be demonstrated for others, such as the definition of various subthreshold bipolar disorders.

  18. Virginia Woolf, neuroprogression, and bipolar disorder

    Directory of Open Access Journals (Sweden)

    Manuela V. Boeira


    Full Text Available Family history and traumatic experiences are factors linked to bipolar disorder. It is known that the lifetime risk of bipolar disorder in relatives of a bipolar proband are 5-10% for first degree relatives and 40-70% for monozygotic co-twins. It is also known that patients with early childhood trauma present earlier onset of bipolar disorder, increased number of manic episodes, and more suicide attempts. We have recently reported that childhood trauma partly mediates the effect of family history on bipolar disorder diagnosis. In light of these findings from the scientific literature, we reviewed the work of British writer Virginia Woolf, who allegedly suffered from bipolar disorder. Her disorder was strongly related to her family background. Moreover, Virginia Woolf was sexually molested by her half siblings for nine years. Her bipolar disorder symptoms presented a pernicious course, associated with hospitalizations, suicidal behavioral, and functional impairment. The concept of neuroprogression has been used to explain the clinical deterioration that takes places in a subgroup of bipolar disorder patients. The examination of Virgina Woolf’s biography and art can provide clinicians with important insights about the course of bipolar disorder.

  19. Bipolar Disorder and Obsessive Compulsive Disorder Comorbidity

    Directory of Open Access Journals (Sweden)

    Necla Keskin


    Full Text Available The comorbidity of bipolar disorder and anxiety disorders is a well known concept. Obsessive-compulsive disorder is the most commonly seen comorbid anxiety disorder in bipolar patients. Some genetic variants, neurotransmitters especially serotonergic systems and second-messenger systems are thought to be responsible for its etiology. Bipolar disorder alters the clinical aspects of obsessive compulsive disorder and is associated with poorer outcome. The determination of comorbidity between bipolar disorder and obsessive compulsive disorder is quite important for appropriate clinical management and treatment. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2014; 6(4.000: 429-437

  20. [Lithium and anticonvulsants in bipolar depression]. (United States)

    Samalin, L; Nourry, A; Llorca, P-M


    For decades, lithium and anticonvulsants have been widely used in the treatment of bipolar disorder. Their efficacy in the treatment of mania is recognized. These drugs have been initially evaluated in old and methodologically heterogeneous studies. Their efficacy in bipolar depression has not always been confirmed in more recent and methodologically more reliable studies. Thus, lithium's efficacy as monotherapy was challenged by the study of Young (2008) that showed a lack of efficacy compared with placebo in the treatment of bipolar depression. In two recent meta-analyses, valproate has shown a modest efficacy in the treatment of bipolar depression. As for lithium, valproate appeared to have a larger antimanic effect for acute phase and prophylaxis of bipolar disorder. In contrast, lamotrigine is more effective on the depressive pole of bipolar disorder with better evidence for the prevention of depressive recurrences. The guidelines include these recent studies and recommend lamotrigine as a first-line treatment of bipolar depression and for maintenance treatment. Because of more discordant data concerning lithium and valproate, these two drugs are placed either as first or as second line treatment of bipolar depression. The different safety/efficacy ratios of mood stabilizers underlie the complementarity and the importance of combination between them, or with some second-generation antipsychotics, in the treatment of patients with bipolar disorder. Copyright © 2011 L’Encéphale. Published by Elsevier Masson SAS.. All rights reserved.

  1. Late Onset Bipolar Disorder: Case Report

    Directory of Open Access Journals (Sweden)

    Filipa Araújo


    Full Text Available Background: Bipolar disorder affects approximately 1% of the population, with diagnosis often being made during late adolescence and early adulthood, and only rarely (0.1% in the elderly. Late onset bipolar disorder in the elderly has a impact on the nature and course of bipolar disorder. Aims: The authors report a case of bipolar disorder emerging in late life  (76years old with no cleary identified organic cause. Conclusion: This case highlights the importance of a broad differential diagnosis and pharmacologic management when approaching new-onset manic/depressive symptoms among geriatric patients.

  2. Dysfunctional gaze processing in bipolar disorder

    Directory of Open Access Journals (Sweden)

    Cristina Berchio


    The present study provides neurophysiological evidence for abnormal gaze processing in BP and suggests dysfunctional processing of direct eye contact as a prominent characteristic of bipolar disorder.

  3. Homer1a protein expression in schizophrenia, bipolar disorder, and major depression. (United States)

    Leber, Stefan L; Llenos, Ida C; Miller, Christine L; Dulay, Jeannette R; Haybaeck, Johannes; Weis, Serge


    In recent years, there was growing interest in postsynaptic density proteins in the central nervous system. Of the most important candidates of this specialized region are proteins belonging to the Homer protein family. This family of scaffolding proteins is suspected to participate in the pathogenesis of a variety of diseases. The present study aims to compare Homer1a expression in the hippocampus and cingulate gyrus of patients with major psychiatric disorders including schizophrenia, bipolar disorder and major depression. Immunohistochemistry was used to analyze changes of Homer1a protein expression in the hippocampal formation and the cingulate gyrus from the respective disease groups. Glial cells of the cingulate gyrus gray matter showed decreased Homer1a levels in bipolar disorder when compared to controls. The same results were seen when comparing cingulate gyrus gray matter glial cells in bipolar disorder with major depression. Stratum oriens glial cells of the hippocampus showed decreased Homer1a levels in bipolar disorder when compared to controls and major depression. Stratum lacunosum glial cells showed decreased Homer1a levels in bipolar disorder when compared to major depression. In stratum oriens interneurons Homer1a levels were increased in all disease groups when compared to controls. Stratum lucidum axons showed decreased Homer1a levels in bipolar disorder when compared to controls. Our data demonstrate altered Homer1a levels in specific brain regions and cell types of patients suffering from schizophrenia, bipolar disorder and major depression. These findings support the role of Homer proteins as interesting candidates in neuropsychiatric pathophysiology and treatment.

  4. Bipolar mixed features - Results from the comparative effectiveness for bipolar disorder (Bipolar CHOICE) study. (United States)

    Tohen, Mauricio; Gold, Alexandra K; Sylvia, Louisa G; Montana, Rebecca E; McElroy, Susan L; Thase, Michael E; Rabideau, Dustin J; Nierenberg, Andrew A; Reilly-Harrington, Noreen A; Friedman, Edward S; Shelton, Richard C; Bowden, Charles L; Singh, Vivek; Deckersbach, Thilo; Ketter, Terence A; Calabrese, Joseph R; Bobo, William V; McInnis, Melvin G


    DSM-5 changed the criteria from DSM-IV for mixed features in mood disorder episodes to include non-overlapping symptoms of depression and hypomania/mania. It is unknown if, by changing these criteria, the same group would qualify for mixed features. We assessed how those meeting DSM-5 criteria for mixed features compare to those meeting DSM-IV criteria. We analyzed data from 482 adult bipolar patients in Bipolar CHOICE, a randomized comparative effectiveness trial. Bipolar diagnoses were confirmed through the MINI International Neuropsychiatric Interview (MINI). Presence and severity of mood symptoms were collected with the Bipolar Inventory of Symptoms Scale (BISS) and linked to DSM-5 and DSM-IV mixed features criteria. Baseline demographics and clinical variables were compared between mood episode groups using ANOVA for continuous variables and chi-square tests for categorical variables. At baseline, the frequency of DSM-IV mixed episodes diagnoses obtained with the MINI was 17% and with the BISS was 20%. Using DSM-5 criteria, 9% of participants met criteria for hypomania/mania with mixed features and 12% met criteria for a depressive episode with mixed features. Symptom severity was also associated with increased mixed features with a high rate of mixed features in patients with mania/hypomania (63.8%) relative to those with depression (8.0%). Data on mixed features were collected at baseline only and thus do not reflect potential patterns in mixed features within this sample across the study duration. The DSM-5 narrower, non-overlapping definition of mixed episodes resulted in fewer patients who met mixed criteria compared to DSM-IV. Copyright © 2017. Published by Elsevier B.V.

  5. Recent Advances in the Study of Bipolar/Rod-Shaped Microglia and their Roles in Neurodegeneration

    Directory of Open Access Journals (Sweden)

    Ngan Pan Bennett Au


    Full Text Available Microglia are the resident immune cells of the central nervous system (CNS and they contribute to primary inflammatory responses following CNS injuries. The morphology of microglia is closely associated with their functional activities. Most previous research efforts have attempted to delineate the role of ramified and amoeboid microglia in the pathogenesis of neurodegenerative diseases. In addition to ramified and amoeboid microglia, bipolar/rod-shaped microglia were first described by Franz Nissl in 1899 and their presence in the brain was closely associated with the pathology of infectious diseases and sleeping disorders. However, studies relating to bipolar/rod-shaped microglia are very limited, largely due to the lack of appropriate in vitro and in vivo experimental models. Recent studies have reported the formation of bipolar/rod-shaped microglia trains in in vivo models of CNS injury, including diffuse brain injury, focal transient ischemia, optic nerve transection and laser-induced ocular hypertension (OHT. These bipolar/rod-shaped microglia formed end-to-end alignments in close proximity to the adjacent injured axons, but they showed no interactions with blood vessels or other types of glial cell. Recent studies have also reported on a highly reproducible in vitro culture model system to enrich bipolar/rod-shaped microglia that acts as a powerful tool with which to characterize this form of microglia. The molecular aspects of bipolar/rod-shaped microglia are of great interest in the field of CNS repair. This review article focuses on studies relating to the morphology and transformation of microglia into the bipolar/rod-shaped form, along with the differential gene expression and spatial distribution of bipolar/rod-shaped microglia in normal and pathological CNSs. The spatial arrangement of bipolar/rod-shaped microglia is crucial in the reorganization and remodeling of neuronal and synaptic circuitry following CNS injuries. Finally, we

  6. Transient Stuttering in Catatonic Bipolar Patients

    Directory of Open Access Journals (Sweden)

    Anthony B. Joseph


    Full Text Available Two cases of transient stuttering occurring in association with catatonia and bipolar disorder are described. Affective decompensation has been associated with lateralized cerebral dysfunction, and it is hypothesized that in some bipolar catatonic patients a concomitant disorder of the lateralization of language function may lead to a variety of clinical presentations including aphasia, mutism, and stuttering.

  7. Swimming in Deep Water: Childhood Bipolar Disorder (United States)

    Senokossoff, Gwyn W.; Stoddard, Kim


    The authors focused on one parent's struggles in finding a diagnosis and intervention for a child who had bipolar disorder. The authors explain the process of identification, diagnosis, and intervention of a child who had bipolar disorder. In addition to the personal story, the authors provide information on the disorder and outline strategies…

  8. Bipolar disorder diagnosis: challenges and future directions (United States)

    Phillips, Mary L; Kupfer, David J


    Bipolar disorder refers to a group of affective disorders, which together are characterised by depressive and manic or hypomanic episodes. These disorders include: bipolar disorder type I (depressive and manic episodes: this disorder can be diagnosed on the basis of one manic episode); bipolar disorder type II (depressive and hypomanic episodes); cyclothymic disorder (hypomanic and depressive symptoms that do not meet criteria for depressive episodes); and bipolar disorder not otherwise specified (depressive and hypomanic-like symptoms that do not meet the diagnostic criteria for any of the aforementioned disorders). Bipolar disorder type II is especially difficult to diagnose accurately because of the difficulty in differentiation of this disorder from recurrent unipolar depression (recurrent depressive episodes) in depressed patients. The identification of objective biomarkers that represent pathophysiologic processes that differ between bipolar disorder and unipolar depression can both inform bipolar disorder diagnosis and provide biological targets for the development of new and personalised treatments. Neuroimaging studies could help the identification of biomarkers that differentiate bipolar disorder from unipolar depression, but the problem in detection of a clear boundary between these disorders suggests that they might be better represented as a continuum of affective disorders. Innovative combinations of neuroimaging and pattern recognition approaches can identify individual patterns of neural structure and function that accurately ascertain where a patient might lie on a behavioural scale. Ultimately, an integrative approach, with several biological measurements using different scales, could yield patterns of biomarkers (biosignatures) to help identify biological targets for personalised and new treatments for all affective disorders. PMID:23663952

  9. Bipolar Disorder and Cognitive Therapy: A Commentary (United States)

    Riskind, John H.


    This article comments on the three articles (Leahy, 2005; Newman, 2005; and Reilly-Harrington & Knauz, 2005) that deal with the applications of cognitive therapy to treatment of bipolar disorder. They focus on the uses of cognitive therapy in treating three important facets of the special problems of bipolar patients: rapid cycling, severe…

  10. Perceived parental rearing of bipolar offspring

    NARCIS (Netherlands)

    Reichart, C. G.; van der Ende, J.; Hillegers, M. H. J.; Wals, M.; Bongers, I. L.; Nolen, W. A.; Ormel, J.; Verhulst, F. C.

    Objective: To explore the impact of growing up with a parent with a bipolar disorder. First, we compared parental rearing behavior perceived by young adult offspring of bipolar parents with parental rearing behavior perceived by same aged young adults from the general population. Secondly, we

  11. Cognitive behavioral therapy for bipolar disorders


    Lotufo Neto, Francisco


    Descrição dos objetivos e principais técnicas da terapia comportamental cognitiva usadas para a psicoterapia das pessoas com transtorno bipolar.Objectives and main techniques of cognitive behavior therapy for the treatment of bipolar disorder patients are described.

  12. Scale-up of Carbon/Carbon Bipolar Plates

    Energy Technology Data Exchange (ETDEWEB)

    David P. Haack


    This project was focused upon developing a unique material technology for use in PEM fuel cell bipolar plates. The carbon/carbon composite material developed in this program is uniquely suited for use in fuel cell systems, as it is lightweight, highly conductive and corrosion resistant. The project further focused upon developing the manufacturing methodology to cost-effectively produce this material for use in commercial fuel cell systems. United Technology Fuel Cells Corp., a leading fuel cell developer was a subcontractor to the project was interested in the performance and low-cost potential of the material. The accomplishments of the program included the development and testing of a low-cost, fully molded, net-shape carbon-carbon bipolar plate. The process to cost-effectively manufacture these carbon-carbon bipolar plates was focused on extensively in this program. Key areas for cost-reduction that received attention in this program was net-shape molding of the detailed flow structures according to end-user design. Correlations between feature detail and process parameters were formed so that mold tooling could be accurately designed to meet a variety of flow field dimensions. A cost model was developed that predicted the cost of manufacture for the product in near-term volumes and long-term volumes (10+ million units per year). Because the roduct uses lowcost raw materials in quantities that are less than competitive tech, it was found that the cost of the product in high volume can be less than with other plate echnologies, and can meet the DOE goal of $4/kW for transportation applications. The excellent performance of the all-carbon plate in net shape was verified in fuel cell testing. Performance equivalent to much higher cost, fully machined graphite plates was found.

  13. On the nature of the fast depolarization of muons in condensed nitrogen

    International Nuclear Information System (INIS)

    Duginov, V.N.; Grebinnik, V.G.; Kirillov, B.F.


    Temperature dependences of the depolarization rate, the muon precession initial amplitude and phase in liquid and crystalline nitrogen with the oxygen content of 10 -6 have been measured. It has been shown that muon spin relaxation parameters in nitrogen do not change at the reduction of the oxygen impurity content from 0.7x10 -4 to 10 -6 . The fast depolarization of muons in condensed nitrogen is apparently due to the formation of muonium atoms. The muon precession initial phase has been measured as a function of the perpendicular magnetic field to determine the state of short-lived muonium in nitrogen. It has been determined that muonium in nitrogen is in an excited state. 14 refs.; 3 figs

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

    Energy Technology Data Exchange (ETDEWEB)

    Genenko, Yuri A., E-mail:; Hirsch, Ofer [Technische Universität Darmstadt, Darmstadt (Germany); Erhart, Paul [Chalmers University of Technology, Gothenburg (Sweden)


    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.

  15. Lactate per se improves the excitability of depolarized rat skeletal muscle by reducing the Cl- conductance

    DEFF Research Database (Denmark)

    de Paoli, Frank Vincenzo; Ørtenblad, Niels; Pedersen, Thomas Holm


    Studies on rats have shown that lactic acid can improve excitability and function of depolarized muscles. The effect has been related to the ensuing reduction in intracellular pH causing inhibition of muscle fibre Cl- channels. Since, however, several carboxylic acids with structural similarities...... to lactate can inhibit muscle Cl- channels it is possible that lactate per se can increase muscle excitability by exerting a direct effect on these channels. We therefore examined effects of lactate on the function of intact muscles and skinned fibres together with effects on pH and Cl- conductance....... In muscles where extracellular compound action potentials (M-waves) and tetanic force response to excitation were reduced by 82±4 and 83±2 %, respectively, by depolarization with 11 mM extracellular K+, both M-waves and force exhibited an up to 4-fold increase when 20 mM lactate was added. This effect...

  16. Neutron depolarization study of internal stresses in amorphous Fe40Ni40B20

    International Nuclear Information System (INIS)

    de Jong, M.; Sietsma, J.; Rekveldt, M.T.; van den Beukel, A.


    The magnetic domain structure of amorphous ferromagnets with nonzero magnetostriction is mainly determined by the internal stress state because of the magneto-elastic coupling. The stress and field dependence of the domain structure contains important information on the internal stresses in the material. The three-dimensional neutron depolarization technique has been used to study the stress- and field-dependence of the bulk domain structures in both as-quenched and annealed ribbons of the metallic glass Fe 40 Ni 40 B 20 . A three-layer domain structure model corresponding to compressive and tensile internal stresses is presented to explain the measured data. The influence of surface roughness on the interpretation of neutron depolarization measurements in amorphous ribbons is discussed. Finally, the internal stress relaxation due to the annealing is explained in terms of the viscous behaviour of the glass. copyright 1997 American Institute of Physics

  17. Quantum key distribution with several intercept-resend attacks via a depolarizing channel

    International Nuclear Information System (INIS)

    Dehmani, Mustapha; Errahmani, Mohamed; Ez-Zahraouy, Hamid; Benyoussef, Abdelilah


    The disturbance effect of a depolarizing channel on the security of the quantum key distribution of the four-state BB84 protocol, with multiple sequential intercept-resend attacks of many eavesdroppers, has been studied. The quantum bit error rate and the mutual information are computed for an arbitrary number N of eavesdroppers. It is found that the quantum error rate decreases with increasing the depolarizing parameter p characterizing the noise of the channel. For p tr of p below which the information is secure and otherwise the information is not secure. The value of p tr decreases with increasing the number of attacks. In contrast, for p ⩾ 0.165, the information is not secure independently of the number of eavesdroppers. Phase diagrams corresponding to the secure—unsecure information are also established. (paper)

  18. Generation of vector beams using a double-wedge depolarizer: Non-quantum entanglement (United States)

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


    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.

  19. Effect of the depolarization field on coherent optical properties in semiconductor quantum dots (United States)

    Mitsumori, Yasuyoshi; Watanabe, Shunta; Asakura, Kenta; Seki, Keisuke; Edamatsu, Keiichi; Akahane, Kouichi; Yamamoto, Naokatsu


    We study the photon echo spectrum of self-assembled semiconductor quantum dots using femtosecond light pulses. The spectrum shape changes from a single-peaked to a double-peaked structure as the time delay between the two excitation pulses is increased. The spectrum change is reproduced by numerical calculations, which include the depolarization field induced by the biexciton-exciton transition as well as the conventional local-field effect for the exciton-ground-state transition in a quantum dot. Our findings suggest that various optical transitions in tightly localized systems generate a depolarization field, which renormalizes the resonant frequency with a change in the polarization itself, leading to unique optical properties.

  20. Coherence and Polarization of Polarization Speckle Generated by Depolarizers and Their Changes through Complex ABCD Matrix

    DEFF Research Database (Denmark)

    Ma, Ning; Hanson, Steen Grüner; Lee, Tim K.


    Recent research work on speckle patterns indicates a variation of the polarization state during propagation and its nonuniformly spatial distribution. The preliminary step for the investigation of this polarization speckle is the generation of the corresponding field. In this paper, a kind...... of special depolarizer: the random roughness birefringent screen (RRBS) is introduced to meet this requirement. The statistical properties of the field generated by the depolarizer is investigated and illustrated in terms of the 2x2 beam coherence and polarization matrix (BCPM) with the corresponding degree...... of coherence (DoC). and degree of polarization (DoP) P. The changes of the coherence and polarization when the speckle field propagates through any optical system are analysed within the framework of the complex ABCD-matrix theory....

  1. PEMFC Performance with Metal Bipolar Plates Depending on the Channel Dimension

    Directory of Open Access Journals (Sweden)

    Kwon Kuikam


    Full Text Available Bipolar plates of a proton exchange membrane fuel cell (PEMFC play an important role in removing liquid phase water as a by-product in order to facilitate the reaction between fuel and oxygen. A great amount of effort has been made to improve the performance of a fuel cell such as maximum current density or maximum power, by improving water removability of a bipolar plate. Most of the studies, however, are conducted numerically because of the complexity of analysing gas and liquid and the poor manufacturability of graphite bipolar plates. In this proceeding, we demonstrate that the performance of a PEMFC with metal bipolar plates can be enhanced by reducing the dimension of the channel. Bipolar plates were machined with stainless steel (type 316L to have three different channel size (1000 μm, 500 μm and 300 μm and the performance of each assembled cells were tested. As a result, the maximum power density and the maximum current density increased by 25%.

  2. Fluorescence/depolarization lidar for mid-range stand-off detection of biological agents (United States)

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


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

  3. Collisional broadening of depolarized spectral lines of hydrogen gases at low temperatures

    International Nuclear Information System (INIS)

    Hout, K.D. van den.


    Experimental results are presented for the collisional broadening and shift of H 2 , D 2 and HD rotational Raman and depolarized Rayleigh lines at various temperatures between 25 K and 300 K. These are then discussed within the context of current theoretical concepts. For a few temperatures the line broadening cross sections are also reported as a function of the ortho-para composition for H 2 and D 2 . (C.F.)

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

    DEFF Research Database (Denmark)

    Ma, Ning; Hanson, Steen Grüner; Takeda, Mitsuo


    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...

  5. Seizures, refractory status epilepticus, and depolarization block as endogenous brain activities (United States)

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


    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.

  6. DeepBipolar: Identifying genomic mutations for bipolar disorder via deep learning. (United States)

    Laksshman, Sundaram; Bhat, Rajendra Rana; Viswanath, Vivek; Li, Xiaolin


    Bipolar disorder, also known as manic depression, is a brain disorder that affects the brain structure of a patient. It results in extreme mood swings, severe states of depression, and overexcitement simultaneously. It is estimated that roughly 3% of the population of the United States (about 5.3 million adults) suffers from bipolar disorder. Recent research efforts like the Twin studies have demonstrated a high heritability factor for the disorder, making genomics a viable alternative for detecting and treating bipolar disorder, in addition to the conventional lengthy and costly postsymptom clinical diagnosis. Motivated by this study, leveraging several emerging deep learning algorithms, we design an end-to-end deep learning architecture (called DeepBipolar) to predict bipolar disorder based on limited genomic data. DeepBipolar adopts the Deep Convolutional Neural Network (DCNN) architecture that automatically extracts features from genotype information to predict the bipolar phenotype. We participated in the Critical Assessment of Genome Interpretation (CAGI) bipolar disorder challenge and DeepBipolar was considered the most successful by the independent assessor. In this work, we thoroughly evaluate the performance of DeepBipolar and analyze the type of signals we believe could have affected the classifier in distinguishing the case samples from the control set. © 2017 Wiley Periodicals, Inc.

  7. A YinYang bipolar fuzzy cognitive TOPSIS method to bipolar disorder diagnosis. (United States)

    Han, Ying; Lu, Zhenyu; Du, Zhenguang; Luo, Qi; Chen, Sheng


    Bipolar disorder is often mis-diagnosed as unipolar depression in the clinical diagnosis. The main reason is that, different from other diseases, bipolarity is the norm rather than exception in bipolar disorder diagnosis. YinYang bipolar fuzzy set captures bipolarity and has been successfully used to construct a unified inference mathematical modeling method to bipolar disorder clinical diagnosis. Nevertheless, symptoms and their interrelationships are not considered in the existing method, circumventing its ability to describe complexity of bipolar disorder. Thus, in this paper, a YinYang bipolar fuzzy multi-criteria group decision making method to bipolar disorder clinical diagnosis is developed. Comparing with the existing method, the new one is more comprehensive. The merits of the new method are listed as follows: First of all, multi-criteria group decision making method is introduced into bipolar disorder diagnosis for considering different symptoms and multiple doctors' opinions. Secondly, the discreet diagnosis principle is adopted by the revised TOPSIS method. Last but not the least, YinYang bipolar fuzzy cognitive map is provided for the understanding of interrelations among symptoms. The illustrated case demonstrates the feasibility, validity, and necessity of the theoretical results obtained. Moreover, the comparison analysis demonstrates that the diagnosis result is more accurate, when interrelations about symptoms are considered in the proposed method. In a conclusion, the main contribution of this paper is to provide a comprehensive mathematical approach to improve the accuracy of bipolar disorder clinical diagnosis, in which both bipolarity and complexity are considered. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Homogenization via the strong-permittivity-fluctuation theory with nonzero depolarization volume (United States)

    Mackay, Tom G.


    The depolarization dyadic provides the scattering response of a single inclusion particle embedded within a homogenous background medium. These dyadics play a central role in formalisms used to estimate the effective constitutive parameters of homogenized composite mediums (HCMs). Conventionally, the inclusion particle is taken to be vanishingly small; this allows the pointwise singularity of the dyadic Green function associated with the background medium to be employed as the depolarization dyadic. A more accurate approach is pursued in this communication by taking into account the nonzero spatial extent of inclusion particles. Depolarization dyadics corresponding to inclusion particles of nonzero volume are incorporated within the strong-permittivity-fluctuation theory (SPFT). The linear dimensions of inclusion particles are assumed to be small relative to the electromagnetic wavelength(s) and the SPFT correlation length. The influence of the size of inclusion particles upon SPFT estimates of the HCM constitutive parameters is investigated for anisotropic dielectric HCMs.In particular, the interplay between correlation length and inclusion size is explored.

  9. Effects of in vitro hypoxia on depolarization-stimulated accumulation of inositol phosphates in synaptosomes

    International Nuclear Information System (INIS)

    Huang, H.M.; Gibson, G.E.


    The effects of potassium and in vitro histotoxic hypoxia on phosphatidylinositol turnover in rat cortical synaptosomes were determined. [2- 3 H] Inositol prelabelled rat synaptosomes were prepared from cerebral cortex slices that had been incubated with [2- 3 H] inositol. Depolarization with 60 mM KCl increased [2- 3 H] inositol phosphates in a time dependent manner. Depolarization with 60 mM KCl increased [2- 3 H]inositol trisphosphate transiently at 5 s. K + induced rapid formation of [2- 3 H] inositol monophosphate with time. One minute of hypoxia enhance sium-stimulate [2 3 H]inositol bisphosphate and maintained an elevated level for at least 5 min. K + stimulated gradual formation of [2- 3 H] inositol monophosphate with time. One minute of hypoxia enhanced potassium-stimulated [2- 3 H] inositol bisphosphate formation. However, 30 min of hypoxia impaired potassium-stimulated accumulation of [2- 3 H]inositol phosphates. The effects of histotoxic hypoxia were all dependent upon calcium in the medium and on K + -depolarization. Thus, hypoxia altered the K + induced accumulation of inositol phosphates in prelabelled synaptosomes in a time dependent, biphasic manner that was calcium dependent

  10. Thermal Stress-Induced Depolarization Loss in Conventional and Panda-Shaped Photonic Crystal Fiber Lasers (United States)

    Mousavi, Seyedeh Laleh; Sabaeian, Mohammad


    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.

  11. First observation of the depolarization of Thomson scattering radiation by a fusion plasma (United States)

    Giudicotti, L.; Kempenaars, M.; McCormack, O.; Flanagan, J.; Pasqualotto, R.; contributors, JET


    We report the first experimental observation of the depolarization of the Thomson scattering (TS) radiation, a relativistic effect expected to occur in very high {{T}e} plasmas and never observed so far in a fusion machine. A set of unused optical fibers in the collection optics of the high resolution Thomson scattering system of JET has been used to detect the depolarized TS radiation during a JET campaign with {{T}e}≤slant 8 keV . A linear polarizer with the axis perpendicular to the direction of the incident E-field was placed in front of a fiber optic pair observing a region close to the plasma core, while another fiber pair with no polariser simultaneously observed an adjacent plasma region. The measured intensity ratio was found to be consistent with the theory, taking into account sensitivity coefficients of the two measurement channels determined with post-experiment calibrations and Raman scattering. This depolarization effect is at the basis of polarimetric TS, a different and complementary method for the analysis of TS spectra that can provide significant advantages for {{T}e} measurements in very hot plasmas such as in ITER ≤ft({{T}e}≤slant 40 keV \\right) .

  12. Ferroelectric behavior of a lead titanate nanosphere due to depolarization fields and mechanical stresses

    Energy Technology Data Exchange (ETDEWEB)

    Andrade Landeta, J.; Lascano, I.


    A theorical model has been developed based on the theory of Ginzburg-Landau-Devonshire to study and predict the effects the decreasing of size particle in a nanosphere of PbTiO3 subjected to the action of depolarization fields and mechanical stress. It was considered that the nanosphere is surrounded by a layer of space charges on its surface, and containing 180° domains generated by minimizing free energy of depolarization. Energy density of depolarization, wall domain and electro-elastic energy have been incorporated into the free energy of the theory Ginzburg-Landau-Devonshire. Free energy minimization was performed to determine the spontaneous polarization and transition temperature system. These results show that the transition temperature for nanosphere is substantially smaller than the corresponding bulk material. Also, it has been obtained that the stability of the ferroelectric phase of nanosphere is favored for configurations with a large number of 180° domains, with the decreasing of thickness space charge layer, and the application of tensile stress and decreases with compressive stress. (Author)

  13. The schizophrenia-associated Kv11.1-3.1 isoform results in reduced current accumulation during repetitive brief depolarizations.

    Directory of Open Access Journals (Sweden)

    Juliane Heide

    Full Text Available Recent genome wide association studies identified a brain and primate specific isoform of a voltage-gated potassium channel, referred to as Kv11.1-3.1, which is significantly associated with schizophrenia. The 3.1 isoform replaces the first 102 amino acids of the most abundant isoform (referred to as Kv11.1-1A with six unique amino acids. Here we show that the Kv11.1-3.1 isoform has faster rates of channel deactivation but a slowing of the rates of inactivation compared to the Kv11.1-1A isoform. The Kv11.1-3.1 isoform also has a significant depolarizing shift in the voltage-dependence of steady-state inactivation. The consequence of the altered gating kinetics is that there is lower current accumulation for Kv11.1-3.1 expressing cells during repetitive action potential firing compared to Kv11.1-1A expressing cells, which in turn will result in longer lasting trains of action potentials. Increased expression of Kv11.1-3.1 channels in the brain of schizophrenia patients might therefore contribute to disorganized neuronal firing.

  14. Biophysical Insights into How Spike Threshold Depends on the Rate of Membrane Potential Depolarization in Type I and Type II Neurons.

    Directory of Open Access Journals (Sweden)

    Guo-Sheng Yi

    Full Text Available 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.

  15. Lower switch rate in depressed patients with bipolar II than bipolar I disorder treated adjunctively with second-generation antidepressants

    NARCIS (Netherlands)

    Altshuler, LL; Suppes, T; Nolen, WA; Leverich, G; Keck, PE; Frye, MA; Kupka, R; McElroy, SL; Grunze, H; Kitchen, CMR; Post, R; Black, D.O.

    Objectives: The authors compared the switch rate into hypomania/mania in depressed patients treated with second-generation antidepressants who had either bipolar I or bipolar II disorder. Method: In a 10-week trial, 184 outpatients with bipolar depression (134 with bipolar I disorder, 48 with

  16. Brief Report: A Family Risk Study Exploring Bipolar Spectrum Problems and Cognitive Biases in Adolescent Children of Bipolar Parents (United States)

    Espie, Jonathan; Jones, Steven H.; Vance, Yvonne H.; Tai, Sara J.


    Children of parents with bipolar disorder are at increased risk of bipolar spectrum diagnoses. This cross-sectional study explores cognitive factors in the prediction of vulnerability to bipolar disorder. Adolescents at high-risk (with a parent with bipolar disorder; n = 23) and age and gender matched adolescents (n = 24) were recruited. Parent…


    Okanović, Milana; Zivanović, Olga


    Polycystic ovarian syndrome is a syndrome of ovarian dysfunction with the principal features of hyperandrogenism and polycystic ovary morphology. A large number of studies conducted on this topic have suggested a possible role of anticonvulsants, particularly valproate, in the pathogenesis or risk factors associated with polycystic ovarian syndrome. Bipolar treatment guidelines from Canada and the United States of America recommend valproate as the first line strategy in the acute treatment of bipolar disorder. Most persons with bipolar disorder require maintenance treatment. Long-term administration of valproate in women with bipolar disorder or epilepsy is believed to result in the increased risk of hyperandrogenism, menstrual abnormalities and polycystic ovaries. Valproate may also increase the risk of infertility and other associated symptoms of polycystic ovarian syndrome. Therefore, particular caution is indicated in the use of valproate in women of reproductive age. The treatment of the female patients with bipolar disorder presents various challenges for the clinician. Every woman of reproductive age needs to know the risk and benefits of her pharmacologic treatment options. Bipolar disorder should be considered chronic disorder, whose development is largely affected by hormonal changes and reproductive cycle in women. These issues should be researched more thoroughly in order to opt for the most appropriate treatment in women with bipolar disorder.

  18. Distinctions of bipolar disorder symptoms in adolescence. (United States)

    Gudiene, Devika; Leskauskas, Darius; Markeviciūte, Aurelija; Klimavicius, Dalius; Adomaitiene, Virginija


    Bipolar disorder in adolescents is a serious mental illness with problematic diagnosis that adversely affects social, academic, emotional, and family functioning. The objective of this study was to analyze features of premorbid and clinical symptoms, comorbidity, and course of bipolar disorder in adolescence. Data for analysis were collected from all case histories (N=6) of 14-18-year-old patients, hospitalized with diagnosis of bipolar disorder in the Unit of Children's and Adolescents' Psychiatry, Department of Psychiatry, Hospital of Kaunas University of Medicine, during the period from 2000 to 2005. Analysis of bipolar disorder course showed that five patients previously had been diagnosed with an episode of depression. The most frequent symptoms typical to bipolar disorder were disobedience and impulsive behavior, rapid changes of mood. The most common premorbid features were frequent changes of mood, being active in communication, hyperactive behavior. Adolescence-onset bipolar disorder was frequently comorbid with emotionally instable personality disorder, borderline type. Findings of the study confirm the notion that oppositional or impulsive behavior, rapid changes of mood without any reason, dysphoric mood and euphoric mood episodes with increased energy were cardinal symptoms of bipolar disorder with mania in adolescents. Most frequent premorbid features of these patients were quite similar to attention-deficit/hyperactivity disorder making differential diagnosis problematic.

  19. Daily electronic self-monitoring of subjective and objective symptoms in bipolar disorder—the MONARCA trial protocol (MONitoring, treAtment and pRediCtion of bipolAr disorder episodes)

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria; Vinberg, Maj; Christensen, Ellen Margrethe


    Electronic self-monitoring of affective symptoms using cell phones is suggested as a practical and inexpensive way to monitor illness activity and identify early signs of affective symptoms. It has never been tested in a randomised clinical trial whether electronic self-monitoring improves outcomes...... in bipolar disorder. We are conducting a trial testing the effect of using a Smartphone for self-monitoring in bipolar disorder....

  20. Therapeutic Targeting of the Mitochondria Initiates Excessive Superoxide Production and Mitochondrial Depolarization Causing Decreased mtDNA Integrity. (United States)

    Pokrzywinski, Kaytee L; Biel, Thomas G; Kryndushkin, Dmitry; Rao, V Ashutosh


    Mitochondrial dysregulation is closely associated with excessive reactive oxygen species (ROS) production. Altered redox homeostasis has been implicated in the onset of several diseases including cancer. Mitochondrial DNA (mtDNA) and proteins are particularly sensitive to ROS as they are in close proximity to the respiratory chain (RC). Mitoquinone (MitoQ), a mitochondria-targeted redox agent, selectively damages breast cancer cells possibly through damage induced via enhanced ROS production. However, the effects of MitoQ and other triphenylphosphonium (TPP+) conjugated agents on cancer mitochondrial homeostasis remain unknown. The primary objective of this study was to determine the impact of mitochondria-targeted agent [(MTAs) conjugated to TPP+: mitoTEMPOL, mitoquinone and mitochromanol-acetate] on mitochondrial physiology and mtDNA integrity in breast (MDA-MB-231) and lung (H23) cancer cells. The integrity of the mtDNA was assessed by quantifying the degree of mtDNA fragmentation and copy number, as well as by measuring mitochondrial proteins essential to mtDNA stability and maintenance (TFAM, SSBP1, TWINKLE, POLG and POLRMT). Mitochondrial status was evaluated by measuring superoxide production, mitochondrial membrane depolarization, oxygen consumption, extracellular acidification and mRNA or protein levels of the RC complexes along with TCA cycle activity. In this study, we demonstrated that all investigated MTAs impair mitochondrial health and decrease mtDNA integrity in MDA-MB-231 and H23 cells. However, differences in the degree of mitochondrial damage and mtDNA degradation suggest unique properties among each MTA that may be cell line, dose and time dependent. Collectively, our study indicates the potential for TPP+ conjugated molecules to impair breast and lung cancer cells by targeting mitochondrial homeostasis.

  1. Paired structures and bipolar knowledge representation

    DEFF Research Database (Denmark)

    Montero, Javier; Bustince, Humberto; Franco, Camilo

    In this strictly positional paper we propose a general approach to bipolar knowledge representation, where the meaning of concepts can be modelled by examining their decomposition into opposite and neutral categories. In particular, it is the semantic relationship between the opposite categories...... and at the same time the type of neutrality rising in between opposites. Based on this first level of bipolar knowledge representation, paired structures in fact offer the means to characterize a specific bipolar valuation scale depending on the meaning of the concept that has to be verified. In this sense...

  2. Bipolar Disorder and Early Affective Trauma. (United States)

    de Codt, Aloise; Monhonval, Pauline; Bongaerts, Xavier; Belkacemi, Ikram; Tecco, Juan Martin


    Bipolar disorder is a chronic psychiatric disease with a high prevalence and is a major psychosocial and medical burden. The exact etiological pathways of bipolar disorder are not fully understood. Genetic factors are known to play an important role in the etiology of bipolar disorder. However, high rates of discordance among identical twins and a growing body of evidence that environmental factors such as early stress can influence the onset and course of psychiatric diseases underline the importance of additional etiological mechanisms of bipolar disorders. There has been little investigation about early trauma in bipolar disorder. The aim of this study was to review the literature on the association between early traumatic interactions like child neglect, mistreatment, abuse or early parental separation and the occurrence of bipolar disorder in adulthood or impact on the course of the disease. Studies investigating associations between child neglect, mistreatment, abuse or early parental separation and occurrence of bipolar disorder in adulthood or impact on the course of the disease were searched in the Pubmed database. More than 700 articles were sorted independently by two of the authors using predefined criteria. Only research articles, reviews and meta-analyses were selected for this review. 53 articles met the inclusion criteria. To date, four systematic reviews partially addressed our research question. Early trauma is more frequently found in the past of bipolar patients than in the general population. Studies support a harmful effect of childhood trauma on the course of bipolar disease, with more anxious, depressive or psychotic symptoms, an early age of onset and a worse prognosis. Early trauma is more often found in the past of bipolar adult patients than the general population and studies support a harmful effect of childhood trauma on the course of bipolar disease, with more anxious, depressive or psychotic symptoms, an early age of onset and a

  3. Ionizing radiations simulation on bipolar components

    International Nuclear Information System (INIS)

    Montagner, X.


    This thesis presents the ionizing radiation effects on bipolar components and more specially their behavior facing the total dose. The first part is devoted to the radiation environments with a special attention to the spatial environments and new emergent environments. The specificities of bipolar components are then presented and their behavior facing the interactions. The physical mechanisms bound to the dose rate are also discussed. The second part presents a physical analysis of degradations induced by the cumulated dosimetry on bipolar components and simulation with the ATLAS code. The third part exposes an electric empirical simulation induced by the cumulated dose in static conditions. (A.L.B.)

  4. Development of new bi-polar plates based on electrically conductive filled polymers for PEMFC

    Energy Technology Data Exchange (ETDEWEB)

    Jousse, F.; Salas, J.F.; Giroud, F. [C.E.A., Le Ripault, Monts (France); Icard, B.; Laurent, J.Y.; Serre Combe, P.


    In polymer electrolyte membrane fuel cell technology, the bi-polar plates are dedicated to: the current collection, the separation and distribution of gas (hydrogen and oxygen) at the cathode and the anode. To achieve these functions, bi-polar plate materials must satisfy the following properties: high conductivity (higher than 10 S/cm), high chemical resistance to acid and water, very low permeability to hydrogen (permeability < Pe{sup H2}{sub Nafion} (20 C) = 7.10{sup -17} m{sup 2}/Pa/s). Traditionally bi-polar plates have been designed with stainless steel or graphite. However, the cost of these plates are incompatible to transport applications, principally because of the gas channel machining step. Recently, we have noticed the work of T.M. Besmann [1] on the manufacturing of bi-polar plates based on carbon fibres and phenolic resin, processed by pyrolisis and densification on surface by a chemical vapour infiltration process. However, this kind of process seems too expensive and complex for the needs of the road electric transportation industry. Organic composites based on conductive chemical resistant fillers and processed by molding could be an alternative solution. Bi-polar plates requirements can be achieved by controlling and optimising experimental parameters such as the nature and morphology of fillers, the resin characteristics, and the process conditions. To avoid corrosion of the composite material, and then, the contamination of the cell, we have selected non metallic fillers, based on graphite or carbon black. (orig.)

  5. Progression along the Bipolar Spectrum: A Longitudinal Study of Predictors of Conversion from Bipolar Spectrum Conditions to Bipolar I and II Disorders (United States)

    Alloy, Lauren B.; Urošević, Snežana; Abramson, Lyn Y.; Jager-Hyman, Shari; Nusslock, Robin; Whitehouse, Wayne G.; Hogan, Michael


    Little longitudinal research has examined progression to more severe bipolar disorders in individuals with “soft” bipolar spectrum conditions. We examine rates and predictors of progression to bipolar I and II diagnoses in a non-patient sample of college-age participants (n = 201) with high General Behavior Inventory scores and childhood or adolescent onset of “soft” bipolar spectrum disorders followed longitudinally for 4.5 years from the Longitudinal Investigation of Bipolar Spectrum (LIBS) project. Of 57 individuals with initial cyclothymia or bipolar disorder not otherwise specified (BiNOS) diagnoses, 42.1% progressed to a bipolar II diagnosis and 10.5% progressed to a bipolar I diagnosis. Of 144 individuals with initial bipolar II diagnoses, 17.4% progressed to a bipolar I diagnosis. Consistent with hypotheses derived from the clinical literature and the Behavioral Approach System (BAS) model of bipolar disorder, and controlling for relevant variables (length of follow-up, initial depressive and hypomanic symptoms, treatment-seeking, and family history), high BAS sensitivity (especially BAS Fun Seeking) predicted a greater likelihood of progression to bipolar II disorder, whereas early age of onset and high impulsivity predicted a greater likelihood of progression to bipolar I (high BAS sensitivity and Fun-Seeking also predicted progression to bipolar I when family history was not controlled). The interaction of high BAS and high Behavioral Inhibition System (BIS) sensitivities also predicted greater likelihood of progression to bipolar I. We discuss implications of the findings for the bipolar spectrum concept, the BAS model of bipolar disorder, and early intervention efforts. PMID:21668080

  6. The thermodynamics of bipolarity: a bifurcation model of bipolar illness and bipolar character and its psychotherapeutic applications. (United States)

    Sabelli, H C; Carlson-Sabelli, L; Javaid, J I


    Two models dominate current formulations of bipolar illness: the homeostatic model implicit in Freud's psychodynamics and most neuroamine deficit/excess theories; and the oscillatory model of exaggerated biological rhythms. The homeostatic model is based on the closed systems approach of classic thermodynamics, while the oscillatory model requires the open systems approach of modern thermodynamics. Here we present a thermodynamic model of bipolarity that includes both homeostatic and oscillatory features and adds the most important feature of open systems thermodynamics: the creation of novel structures in bifurcation processes. According to the proposed model, bipolarity is the result of exaggerated biological energy that augments homeostatic, oscillatory and creative psychological processes. Only low-energy closed systems tend to rest ("point attractor") and entropic disorder. Open processes containing and exchanging energy fluctuate between opposite states ("periodic attractors"); they are characteristic of most physiological rhythms and are exaggerated in bipolar subjects. At higher energies, their strong fluctuations destroy pre-existing patterns and structures, produce turbulence ("chaotic attractors"), which sudden switches between opposite states, and create new and more complex structures. Likewise, high-energy bipolars develop high spontaneity, great fluctuations between opposite moods, internal and interpersonal chaos, and enhanced creativity (personal, artistic, professional) as well as psychopathology (personality deviations, psychotic delusions). Offered here is a theoretical explanation of the dual--creative and destructive--nature of bipolarity in terms of the new enantiodromic concept of entropy generalized by process theory. Clinically, this article offers an integrative model of bipolarity that accounts for many clinical features and contributes to a definition of the bipolar personality.

  7. Unraveling the biology of bipolar disorder using induced pluripotent stem-derived neurons. (United States)

    Miller, Nathaniel D; Kelsoe, John R


    Bipolar disorder has been studied from numerous angles, from pathological studies to large-scale genomic studies, overall making moderate gains toward an understanding of the disorder. With the advancement of induced pluripotent stem (iPS) cell technology, in vitro models based on patient samples are now available that inherently incorporate the complex genetic variants that largely are the basis for this disorder. A number of groups are starting to apply iPS technology to the study of bipolar disorder. We selectively reviewed the literature related to understanding bipolar disorder based on using neurons derived from iPS cells. So far, most work has used the prototypical iPS cells. However, others have been able to transdifferentiate fibroblasts directly to neurons. Others still have utilized olfactory epithelium tissue as a source of neural-like cells that do not need reprogramming. In general, iPS and related cells can be used for studies of disease pathology, drug discovery, or stem cell therapy. Published studies have primarily focused on understanding bipolar disorder pathology, but initial work is also being done to use iPS technology for drug discovery. In terms of disease pathology, some evidence is pointing toward a differentiation defect with more ventral cell types being prominent. Additionally, there is evidence for a calcium signaling defect, a finding that builds on the genome-wide association study results. Continued work with iPS cells will certainly help us understand bipolar disorder and provide a way forward for improved treatments. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Bipolar Electrode Sample Preparation Devices (United States)

    Wang, Yi (Inventor); Song, Hongjun (Inventor); Pant, Kapil (Inventor)


    An analyte selection device can include: a body defining a fluid channel having a channel inlet and channel outlet; a bipolar electrode (BPE) between the inlet and outlet; one of an anode or cathode electrically coupled with the BPE on a channel inlet side of the BPE and the other of the anode or cathode electrically coupled with the BPE on a channel outlet side of the BPE; and an electronic system operably coupled with the anode and cathode so as to polarize the BPE. The fluid channel can have any shape or dimension. The channel inlet and channel outlet can be longitudinal or lateral with respect to the longitudinal axis of the channel. The BPE can be any metallic member, such as a flat plate on a wall or mesh as a barrier BPE. The anode and cathode can be located at a position that polarizes the BPE.

  9. Climatic factors and bipolar affective disorder

    DEFF Research Database (Denmark)

    Christensen, Ellen Margrethe; Larsen, Jens Knud; Gjerris, Annette


    In bipolar disorder, the factors provoking a new episode are unknown. As a seasonal variation has been noticed, it has been suggested that weather conditions may play a role. The aim of the study was to elucidate whether meteorological parameters influence the development of new bipolar phases....... A group of patients with at least three previous hospitalizations for bipolar disorder was examined every 3 months for up to 3 years. At each examination an evaluation of the affective phase was made according to the Hamilton Depression Scale (HAM-D(17)), and the Bech-Rafaelsen Mania Rating Scale (MAS......). In the same period, daily recordings from the Danish Meteorological Institute were received. We found no correlations between onset of bipolar episodes [defined as MAS score of 11 or more (mania) and as HAM-D(17) score of 12 or more (depression)] and any meteorological parameters. We found a statistical...

  10. Bipolar or unipolar? : A brain teasing question

    NARCIS (Netherlands)

    Rive, M.M.


    During the depressed or remitted states, major depressive disorder (MDD) and bipolar disorder (BD) are difficult to distinguish clinically. Treatments for both disorders differ, and inadequate treatment may lead to chronicity, poor psychosocial functioning, or even suicide. Although early

  11. Internet use by patients with bipolar disorder

    DEFF Research Database (Denmark)

    Bauer, Rita; Conell, Jörn; Glenn, Tasha


    There is considerable international interest in online education of patients with bipolar disorder, yet little understanding of how patients use the Internet and other sources to seek information. 1171 patients with a diagnosis of bipolar disorder in 17 countries completed a paper-based, anonymous...... survey. 81% of the patients used the Internet, a percentage similar to the general public. Older age, less education, and challenges in country telecommunications infrastructure and demographics decreased the odds of using the Internet. About 78% of the Internet users looked online for information...... on bipolar disorder or 63% of the total sample. More years of education in relation to the country mean, and feeling very confident about managing life decreased the odds of seeking information on bipolar disorder online, while having attended support groups increased the odds. Patients who looked online...

  12. Are rates of pediatric bipolar disorder increasing?

    DEFF Research Database (Denmark)

    Kessing, Lars Vedel; Vradi, Eleni; Andersen, Per Kragh


    Studies from the USA suggest that rates of pediatric bipolar disorder have increased since the mid-90s, but no study outside the USA has been published on the rates of pediatric bipolar disorder. Further, it is unclear whether an increase in rates reflects a true increase in the illness or more...... diagnostic attention. Using nationwide registers of all inpatients and outpatients contacts to all psychiatric hospitals in Denmark, we investigated (1) gender-specific rates of incident pediatric mania/bipolar disorder during a period from 1995 to 2012, (2) whether age and other characteristics...... for pediatric mania/bipolar disorder changed during the calendar period (1995 to 2003 versus 2004 to 2012), and (3) whether the diagnosis is more often made at first psychiatric contact in recent time compared to earlier according to gender. Totally, 346 patients got a main diagnosis of a manic episode (F30...

  13. Life cycle test results of a bipolar nickel hydrogen battery (United States)

    Cataldo, R. L.


    A history is given of low Earth orbit (LEO) laboratory test data on a 6.5 ampere-hour bipolar nickel hydrogen battery designed and built at the NASA Lewis Research Center. The bipolar concept is a means of achieving the goal of producing an acceptable battery, of higher energy density, able to withstand the demands of low-Earth-orbit regimes. Over 4100 LEO cycles were established on a ten cell battery. It seems that any perturbation on normal cycling effects the cells performance. Explanations and theories of the battery's behavior are varied and widespread among those closely associated with it. Deep discharging does provide a reconditioning effect and further experimentation is planned in this area. The battery watt-hour efficiency is about 75 percent and the time averaged, discharge voltage is about 1.26 volts for all cells at both the C/4 and LEO rate. Since a significant portion of the electrode capacity has degraded, the LEO cycle discharges are approaching depths of 90 to 100 percent of the high rate capacity. Therefore, the low end-of-discharge voltages occur precipitously after the knee of the discharge curve and is more an indication of electrode capacity and is a lesser indicator of overall cell performance.

  14. Oxygen and Glucose Deprivation Induces Bergmann Glia Membrane Depolarization and Ca2+ Rises Mainly Mediated by K+ and ATP Increases in the Extracellular Space

    Directory of Open Access Journals (Sweden)

    Romain Helleringer


    Full Text Available During brain ischemia, intense energy deficiency induces a complex succession of events including pump failure, acidosis and exacerbated glutamate release. In the cerebellum, glutamate is the principal mediator of Purkinje neuron anoxic depolarization during episodes of oxygen and glucose deprivation (OGD. Here, the impact of OGD is studied in Bergmann glia, specialized astrocytes closely associated to Purkinje neurons. Patch clamp experiments reveal that during OGD Bergmann glial cells develop a large depolarizing current that is not mediated by glutamate and purinergic receptors but is mainly due to the accumulation of K+ in the extracellular space. Furthermore, we also found that increases in the intracellular Ca2+ concentration appear in Bergmann glia processes several minutes following OGD. These elevations require, in an early phase, Ca2+ mobilization from internal stores via P2Y receptor activation, and, over longer periods, Ca2+ entry through store-operated calcium channels. Our results suggest that increases of K+ and ATP concentrations in the extracellular space are primordial mediators of the OGD effects on Bergmann glia. In the cerebellum, glial responses to energy deprivation-triggering events are therefore highly likely to follow largely distinct rules from those of their neuronal counterparts.

  15. Biological dysrhythm in remitted bipolar I disorder. (United States)

    Iyer, Aishwarya; Palaniappan, Pradeep


    Recent treatment guidelines support treatment of biological rhythm abnormalities as a part of treatment of bipolar disorder, but still, literature examining various domains (Sleep, Activity, Social, and Eating) of biological rhythm and its clinical predictors are less. The main aim of our study is to compare various domains of biological rhythm among remitted bipolar I subjects and healthy controls. We also explored for any association between clinical variables and biological rhythm among bipolar subjects. 40 subjects with Bipolar I disorder and 40 healthy controls who met inclusion and exclusion criteria were recruited for the study. Diagnoses were ascertained by a qualified psychiatrist using MINI 5.0. Sociodemographic details, biological rhythm (BRIAN-Biological Rhythm Interview of assessment in Neuropsychiatry) and Sleep functioning (PSQI- Pittsburgh Sleep Quality Index) were assessed in all subjects. Mean age of the Bipolar subjects and controls were 41.25±11.84years and 38.25±11.25 years respectively. Bipolar subjects experienced more biological rhythm disturbance when compared to healthy controls (total BRIAN score being 34.25±9.36 vs 28.2±6.53) (p=0.002). Subsyndromal depressive symptoms (HDRS) had significant positive correlation with BRIAN global scores(r=0.368, p=0.02). Linear regression analysis showed that number of episodes which required hospitalization (β=0.601, t=3.106, P=0.004), PSQI (β=0.394, t=2.609, p=0.014), HDRS (β=0.376, t=2.34, t=0.036) explained 31% of variance in BRIAN scores in remitted bipolar subjects. Biological rhythm disturbances seem to persist even after clinical remission of bipolar illness. More studies to look into the impact of subsyndromal depressive symptoms on biological rhythm are needed. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Suicide in bipolar disorder: a review. (United States)

    Latalova, Klara; Kamaradova, Dana; Prasko, Jan


    Suicide is a leading cause of death in patients with bipolar disorder. Risk factors and prevention of suicide in this illness are the focus of considerable current research. MEDLINE data base was searched for the key words "bipolar disorder" with "suicide", "lithium" with "suicide", "anticonvulsants" with "bipolar disorder", and "anticonvulsants" with "bipolar disorder" and with "suicide". No language or time constraints were applied. The lists of references were searched manually to find additional articles. It is estimated that 25% to 50% of patients with bipolar disorder will attempt suicide at least once over their lifetime, and that 8% to 19% will complete suicide. Mortality rates from cardiovascular diseases are elevated in bipolar disorder. Risk factors for suicide include younger age of onset of the illness, history of past suicidal behavior, family history of suicide acts, comorbid borderline personality disorder and substance use disorders, and hopelessness. The warning signs calling for immediate action include the patients threatening to harm themselves, or looking for ways to kill themselves (seeking access to pills or weapons), or the patient talking or writing about death. Robust evidence supports the effects of lithium treatment in reducing suicidal attempts and completions in bipolar disorder. The evidence for antisuicidal effects of anticonvulsants is weaker. Nevertheless, valproate and other anticonvulsants are frequently prescribed as mood stabilizers. There have been controversial suggestions that this treatment may elevate the risk of suicide, but the data supporting this are not convincing. Psychoeducation can reduce the number of suicide attempts and completions. Suicide in bipolar disorder is a major public health problem. Recent research has expanded our knowledge of risk factors and warning signs. Nevertheless, it appears that the introduction of lithium treatment in the 1970s was the most recent important breakthrough in the prevention

  17. Preparation of bipolar membranes by electrospinning

    International Nuclear Information System (INIS)

    Pan, Jiefeng; Hou, Linxiao; Wang, Qiuyue; He, Yubin; Wu, Liang; Mondal, Abhishek N.; Xu, Tongwen


    A new preparative pathway for the bipolar membranes was initiated via the electrospinning and hot-press process. The prepared bipolar membrane was consisting of sulfonated poly (phenylene oxide), polyethylene glycol, and quaternized poly (phenylene oxide). The above mentioned membrane was fabricated by the continuous electrospinning of the respective layer, followed by the solvent atmosphere treatment and hot-pressing, to obtain a transparent and dense structure. The thickness of each layer can be easily tuned by controlling the electrospinning parameters. The clear interfacial structure was observed and confirmed by the scanning electron microscope. The bipolar performance is evaluated by the current–voltage curves and production yield of acid and base. The final optimized bipolar membrane had similar yield of acid and base as the casting membrane. However, extremely lower potential drop value was observed when they are applied for the production of acid and base. The experimental results showed that, electrospinning is an effective and well controlled way to fabricate bipolar membranes, in which anion or cation exchange layer as well as interfacial layer can be easily changed or added as requested. - Highlights: • Bipolar membranes were prepared through electrospinning followed by post-treatment. • As-prepared membranes were successfully applied in electrodialysis for production of acid and base. • Electrospun membranes exhibit better performance than the casting ones.

  18. Preparation of bipolar membranes by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Jiefeng; Hou, Linxiao; Wang, Qiuyue; He, Yubin; Wu, Liang; Mondal, Abhishek N.; Xu, Tongwen, E-mail:


    A new preparative pathway for the bipolar membranes was initiated via the electrospinning and hot-press process. The prepared bipolar membrane was consisting of sulfonated poly (phenylene oxide), polyethylene glycol, and quaternized poly (phenylene oxide). The above mentioned membrane was fabricated by the continuous electrospinning of the respective layer, followed by the solvent atmosphere treatment and hot-pressing, to obtain a transparent and dense structure. The thickness of each layer can be easily tuned by controlling the electrospinning parameters. The clear interfacial structure was observed and confirmed by the scanning electron microscope. The bipolar performance is evaluated by the current–voltage curves and production yield of acid and base. The final optimized bipolar membrane had similar yield of acid and base as the casting membrane. However, extremely lower potential drop value was observed when they are applied for the production of acid and base. The experimental results showed that, electrospinning is an effective and well controlled way to fabricate bipolar membranes, in which anion or cation exchange layer as well as interfacial layer can be easily changed or added as requested. - Highlights: • Bipolar membranes were prepared through electrospinning followed by post-treatment. • As-prepared membranes were successfully applied in electrodialysis for production of acid and base. • Electrospun membranes exhibit better performance than the casting ones.

  19. Comorbidity bipolar disorder and personality disorders. (United States)

    Latalova, Klara; Prasko, Jan; Kamaradova, Dana; Sedlackova, Jana; Ociskova, Marie


    Outcome in bipolar patients can be affected by comorbidity of other psychiatric disorders. Comorbid personality disorders are frequent and may complicate the course of bipolar illness. We have much information about treating patients with uncomplicated bipolar disorder (BD) but much less knowledge about possibilities for patients with the comorbidity of BD and personality disorder. We conducted a series of literature searches using, as key words or as items in indexed fields, bipolar disorder and personality disorder or personality traits. Articles were obtained by searching MEDLINE from 1970 to 2012. In addition, we used other papers cited in articles from these searches, or cited in articles used in our own work. Tests of personality traits indicated that euthymic bipolar patients have higher scores on harm avoidance, reward dependence, and novelty seeking than controls. Elevation of novelty seeking in bipolar patients is associated with substance abuse comorbidity. Comorbidity with personality disorders in BD patients is associated with a more difficult course of illness (such as longer episodes, shorter time euthymic, and earlier age at onset) and an increase in comorbid substance abuse, suicidality and aggression. These problems are particularly pronounced in comorbidity with borderline personality disorder. Comorbidity with antisocial personality disorder elicits a similar spectrum of difficulties; some of the antisocial behavior exhibited by patients with this comorbidity is mediated by increased impulsivity.

  20. The role of sleep in bipolar disorder

    Directory of Open Access Journals (Sweden)

    Gold AK


    Full Text Available Alexandra K Gold,1 Louisa G Sylvia,1,2 1Department of Psychiatry, Massachusetts General Hospital, 2Harvard Medical School, Boston, MA, USA Abstract: Bipolar disorder is a serious mental illness characterized by alternating periods of elevated and depressed mood. Sleep disturbances in bipolar disorder are present during all stages of the condition and exert a negative impact on overall course, quality of life, and treatment outcomes. We examine the partnership between circadian system (process C functioning and sleep–wake homeostasis (process S on optimal sleep functioning and explore the role of disruptions in both systems on sleep disturbances in bipolar disorder. A convergence of evidence suggests that sleep problems in bipolar disorder result from dysregulation across both process C and process S systems. Biomarkers of depressive episodes include heightened fragmentation of rapid eye movement (REM sleep, reduced REM latency, increased REM density, and a greater percentage of awakenings, while biomarkers of manic episodes include reduced REM latency, greater percentage of stage I sleep, increased REM density, discontinuous sleep patterns, shortened total sleep time, and a greater time awake in bed. These findings highlight the importance of targeting novel treatments for sleep disturbance in bipolar disorder. Keywords: bipolar disorder, circadian rhythms, sleep–wake homeostasis

  1. Classification of cognitive performance in bipolar disorder. (United States)

    Sparding, Timea; Silander, Katja; Pålsson, Erik; Östlind, Josefin; Ekman, Carl Johan; Sellgren, Carl M; Joas, Erik; Hansen, Stefan; Landén, Mikael


    To understand the etiology of cognitive impairment associated with bipolar disorder, we need to clarify potential heterogeneity in cognitive functioning. To this end, we used multivariate techniques to study if the correlation structure of cognitive abilities differs between persons with bipolar disorder and controls. Clinically stable patients with bipolar disorder (type I: n = 64; type II: n = 44) and healthy controls (n = 86) were assessed with a wide range of cognitive tests measuring executive function, speed, memory, and verbal skills. Data were analysed with multivariate techniques. A distinct subgroup (∼30%) could be identified that performed significantly poorer on tests concerning memory function. This cognitive phenotype subgroup did not differ from the majority of bipolar disorder patients with respect to other demographic or clinical characteristics. Whereas the majority of patients performed similar to controls, a subgroup of patients with bipolar disorder differed substantially from healthy controls in the correlation pattern of low-level cognitive abilities. This suggests that cognitive impairment is not a general trait in bipolar disorder but characteristic of a cognitive subgroup. This has important clinical implications for cognitive rehabilitation and remediation.

  2. O transtorno bipolar na mulher Bipolar disorder in women

    Directory of Open Access Journals (Sweden)

    Alexandro de Borja Gonçalves Guerra


    Full Text Available Diferenças sexuais, descritas em vários transtornos psiquiátricos, também parecem estar presentes no transtorno afetivo bipolar (TAB. A prevalência do TAB tipo I se distribui igualmente entre mulheres e homens. Mulheres parecem estar sujeitas a um risco maior de ciclagem rápida e mania mista, condições que fariam do TAB um transtorno com curso mais prejudicial no sexo feminino. Uma diátese depressiva mais marcante, uso excessivo de antidepressivos e diferenças hormonais surgem como hipóteses para explicar essas diferenças fenomenológicas, apesar das quais, mulheres e homens parecem responder igualmente ao tratamento medicamentoso. A indicação de anticonvulsivantes como primeira escolha em mulheres é controversa, a não ser para o tratamento da mania mista e, talvez, da ciclagem rápida. O tratamento do TAB na gravidez deve levar em conta tanto os riscos de exposição aos medicamentos quanto à doença materna. A profilaxia do TAB no puerpério está fortemente indicada em decorrência do grande risco de recorrência da doença nesse período. Embora, de modo geral, as medicações psicotrópicas estejam contra-indicadas durante a amamentação, entre os estabilizadores do humor, a carbamazepina e o valproato são mais seguros do que o lítio. Mais estudos são necessários para a confirmação das diferenças de curso do TAB entre mulheres e homens e a investigação de possíveis diferenças na efetividade dos tratamentos.Gender differences, described in several psychiatric disorders, seem to be also present in bipolar disorder (BD. The prevalence of bipolar I disorder is equally distributed between women and men. Women seem to be at higher risk for rapid cycling and mixed mania, conditions that could make BD a disorder with a more severe course in the female sex. A marked depressive diathesis among women, greatest use of antidepressants and hormonal differences have been mentioned as hypotheses to explain these

  3. Postsynaptic Depolarization Enhances GABA Drive to Dorsomedial Hypothalamic Neurons through Somatodendritic Cholecystokinin Release. (United States)

    Crosby, Karen M; Baimoukhametova, Dinara V; Bains, Jaideep S; Pittman, Quentin J


    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. Copyright © 2015 the authors 0270-6474/15/3513160-11$15.00/0.

  4. Using Smartphones to Monitor Bipolar Disorder Symptoms: A Pilot Study. (United States)

    Beiwinkel, Till; Kindermann, Sally; Maier, Andreas; Kerl, Christopher; Moock, Jörn; Barbian, Guido; Rössler, Wulf


    Relapse prevention in bipolar disorder can be improved by monitoring symptoms in patients' daily life. Smartphone apps are easy-to-use, low-cost tools that can be used to assess this information. To date, few studies have examined the usefulness of smartphone data for monitoring symptoms in bipolar disorder. We present results from a pilot test of a smartphone-based monitoring system, Social Information Monitoring for Patients with Bipolar Affective Disorder (SIMBA), that tracked daily mood, physical activity, and social communication in 13 patients. The objective of this study was to investigate whether smartphone measurements predicted clinical symptoms levels and clinical symptom change. The hypotheses that smartphone measurements are (1) negatively related to clinical depressive symptoms and (2) positively related to clinical manic symptoms were tested. Clinical rating scales were administered to assess clinical depressive and manic symptoms. Patients used a smartphone with the monitoring app for up to 12 months. Random-coefficient multilevel models were computed to analyze the relationship between smartphone data and externally rated manic and depressive symptoms. Overall clinical symptom levels and clinical symptom changes were predicted by separating between-patient and within-patient effects. Using established clinical thresholds from the literature, marginal effect plots displayed clinical relevance of smartphone data. Overall symptom levels and change in clinical symptoms were related to smartphone measures. Higher overall levels of clinical depressive symptoms were predicted by lower self-reported mood measured by the smartphone (beta=-.56, Psmartphone (ie, cell tower movements: beta=-.11, P=.03). Higher overall levels of clinical manic symptoms were predicted by lower physical activity on the smartphone (ie, distance travelled: beta=-.37, Psmartphone (beta=-.17, Psmartphone measurements, but not all smartphone measures predicted the occurrence of

  5. Development of a pressurized bipolar alkaline water electrolyzer

    Energy Technology Data Exchange (ETDEWEB)

    Neves Junior, Newton Pimenta; Pinto, Edgar A. de Godoi Rodrigues; Silva, Ennio Peres da; Rapelli, Rubia; Pinto, Cristiano da Silva [Universidade Estadual de Campinas (DFA/ IFGW/UNICAMP), SP (Brazil). Inst. de Fisica Gleb Wataghin. Dept. de Fisica Aplicada], Email:; Marin Neto, Antonio Jose; Lopes, Daniel Gabriel; Camargo, Joao Carlos; Ferreira, Paulo F.P. [Hydrogen Technology (HyTron), Campinas, SP (Brazil); Furlan, Andre Luis [Universidade Estadual de Campinas (DE/FEC/UNICAMP), SP (Brazil). Fac. de Engenharia Mecanica


    This paper reports the actual development status of a bipolar alkaline water electrolyzer with maximum production capacity of 1 m3/h of hydrogen and controlled by a PLC (Programmable Logic Controller), which also interfaces the electrolytic system with operators and other equipment, such as gas storage tanks, fuel cells and photovoltaic panels. The project also includes the construction of an electrolysis test bench to record electrical parameters (cathode, anode, separator and electrolyte potentials), the amount of produced gases and gas quality determined by gas chromatography. (author)

  6. Accuracy of depolarization and delay spread predictions using advanced ray-based modeling in indoor scenarios

    Directory of Open Access Journals (Sweden)

    Mani Francesco


    Full Text Available Abstract This article investigates the prediction accuracy of an advanced deterministic propagation model in terms of channel depolarization and frequency selectivity for indoor wireless propagation. In addition to specular reflection and diffraction, the developed ray tracing tool considers penetration through dielectric blocks and/or diffuse scattering mechanisms. The sensitivity and prediction accuracy analysis is based on two measurement campaigns carried out in a warehouse and an office building. It is shown that the implementation of diffuse scattering into RT significantly increases the accuracy of the cross-polar discrimination prediction, whereas the delay-spread prediction is only marginally improved.

  7. Depolarization corrections to the coercive field in thin-film ferroelectrics

    International Nuclear Information System (INIS)

    Dawber, M; Chandra, P; Littlewood, P B; Scott, J F


    Empirically, the coercive field needed to reverse the polarization in a ferroelectric increases with decreasing film thickness. For ferroelectric films of 100 μm to 100 nm in thickness the coercive field has been successfully described by a semi-empirical scaling law. Accounting for depolarization corrections, we show that this scaling behaviour is consistent with field measurements of ultrathin ferroelectric capacitors down to one nanometre in film thickness. Our results also indicate that the minimum film thickness, determined by a polarization instability, can be tuned by the choice of electrodes, and recommendations for next-generation ferroelectric devices are discussed. (letter to the editor)

  8. Depolarization corrections to the coercive field in thin-film ferroelectrics

    CERN Document Server

    Dawber, M; Littlewood, P B; Scott, J F


    Empirically, the coercive field needed to reverse the polarization in a ferroelectric increases with decreasing film thickness. For ferroelectric films of 100 mu m to 100 nm in thickness the coercive field has been successfully described by a semi-empirical scaling law. Accounting for depolarization corrections, we show that this scaling behaviour is consistent with field measurements of ultrathin ferroelectric capacitors down to one nanometre in film thickness. Our results also indicate that the minimum film thickness, determined by a polarization instability, can be tuned by the choice of electrodes, and recommendations for next-generation ferroelectric devices are discussed. (letter to the editor)

  9. A neutron depolarization study of magnetic inhomogeneities in weak-link superconductors

    International Nuclear Information System (INIS)

    Zhuchenko, N.K.; Yagud, R.Z.


    Neutron depolarization measurements in the mixed state of both high-T c and low-T c weak-link superconductors have been carried out. Samples of YBCO, BSCCO, SnMo 6 S 8 and 0.5 Nb-0.5 Ti of different magnetic prehistory were analyzed at temperatures T 4.2 K under applied magnetic fields II <= 16.5 kOe. We ascribe the appearance of magnetic inhomogeneities and their hysteresis behaviour to the interaction between dipole magnetic fields (diamagnetic and paramagnetic ones) and applied magnetic fields

  10. The use of thermally stimulated depolarization currents to study grain growth in ceramic thorium dioxide

    International Nuclear Information System (INIS)

    Muccillo, R.; Campos, L.L.


    Depolarization Current Spectra resulting from the destruction of the thermoelectret state in polycrystalline ThO 2 samples have been detected in the temperature range 100K-350K. The induced polarization is found to be due to migration of charge carriers over microscopic distances in the bulk of the specimens with trapping at grain boundaries. Moreover the density of charge carriers released from trapping sites, upon heating the cooled previously dc biased specimen decreases for increasing sintering temperature, suggesting the use of the technique to the study of grain growth in the bulk of ceramic oxides. (Author) [pt

  11. Magnetic-field dependence of impurity-induced muon depolarization in noble metals

    International Nuclear Information System (INIS)

    Schillaci, M.E.; Heffner, R.H.; Hutson, R.L.; Leon, M.; Cooke, D.W.; Dodds, S.A.; Richards, P.M.; MacLaughlin, D.E.; Boekema, C.


    We have measured the magnetic-field dependence of the muon depolarization rate up to 5 kOe in AuGd (350 ppM), AgGd (340 ppM) and AgEr (300 ppM). A simple model which includes both dipolar and nearest-neighbor contact interactions between the muon and the magnetic impurity does not fit the data. An axial crystal-field interaction, arising from the electric-field gradient induced by the muon at the site of the impurity, is found to dominate the Hamiltonian, and may have a large effect on the field dependence

  12. Magnetic field dependence of impurity-induced muon depolarization in noble metals

    Energy Technology Data Exchange (ETDEWEB)

    Schillaci, M.E.; Heffner, R.H.; Hutson, R.L.; Leon, M.; Cooke, D.W.; Yaouanc, A. (Los Alamos National Lab., NM (USA)); Dodds, S.A. (Rice Univ., Houston, TX (USA). Dept. of Physics); Richards, P.M. (Sandia National Labs., Albuquerque, NM (USA)); MacLaughlin, D.E. (California Univ., Riverside (USA)); Boekema, C. (Texas Tech Univ., Lubbock (USA))


    The authors have measured the magnetic field dependence of the muon depolarization rate up to 5 kOe in AuGd (350 ppm), AgGd (340 ppm) and AgEr (300 ppm). A simple model which includes both dipolar and nearest-neighbor contact interactions between the muon and the magnetic impurity does not fit the data. An axial crystal-field interaction, arising from the electric field gradient induced by the muon at the site of the impurity, is found to dominate the Hamiltonian, and may have a large effect on the field dependence.

  13. Electrogenic glutamate uptake is a major current carrier in the membrane of axolotl retinal glial cells (United States)

    Brew, Helen; Attwell, David


    Glutamate is taken up avidly by glial cells in the central nervous system1. Glutamate uptake may terminate the transmitter action of glutamate released from neurons1, and keep extracellular glutamate at concentrations below those which are neurotoxic. We report here that glutamate evokes a large inward current in retinal glial cells which have their membrane potential and intracellular ion concentrations controlled by the whole-cell patch-clamp technique2. This current seems to be due to an electrogenic glutamate uptake carrier, which transports at least two sodium ions with every glutamate anion carried into the cell. Glutamate uptake is strongly voltage-dependent, decreasing at depolarized potentials: when fully activated, it contributes almost half of the conductance in the part of the glial cell membrane facing the retinal neurons. The spatial localization, glutamate affinity and magnitude of the uptake are appropriate for terminating the synaptic action of glutamate released from photoreceptors and bipolar cells. These data challenge present explanations of how the b-wave of the electroretinogram is generated, and suggest a mechanism for non-vesicular voltage-dependent release of glutamate from neurons.

  14. Description of bipolar charge transport in polyethylene using a fluid model with a constant mobility: model prediction

    International Nuclear Information System (INIS)

    Le Roy, S; Segur, P; Teyssedre, G; Laurent, C


    We present a conduction model aimed at describing bipolar transport and space charge phenomena in low density polyethylene under dc stress. In the first part we recall the basic requirements for the description of charge transport and charge storage in disordered media with emphasis on the case of polyethylene. A quick review of available conduction models is presented and our approach is compared with these models. Then, the bases of the model are described and related assumptions are discussed. Finally, results on external current, trapped and free space charge distributions, field distribution and recombination rate are presented and discussed, considering a constant dc voltage, a step-increase of the voltage, and a polarization-depolarization protocol for the applied voltage. It is shown that the model is able to describe the general features reported for external current, electroluminescence and charge distribution in polyethylene

  15. Electric field with bipolar structure during magnetic reconnection without a guide field (United States)

    Guo, Jun


    We present a study on the polarized electric field during the collisionless magnetic reconnection of antiparallel fields using two dimensional particle-in-cell simulations. The simulations demonstrate clearly that electron holes and electric field with bipolar structure are produced during magnetic reconnection without a guide field. The electric field with bipolar structure can be found near the X-line and on the separatrix and the plasma sheet boundary layer, which is consistent with the observations. These structures will elongate electron's time staying in the diffusion region. In addition, the electric fields with tripolar structures are also found in our simulation.

  16. Parametric and cycle tests of a 40-AH bipolar nickel-hydrogen battery (United States)

    Cataldo, R. L.


    The performance of a 12 V, 40 ampere-hour bipolar battery during various charge current, discharge current, temperature, and pressure operating conditions is investigated. The cell voltages, temperatures, ampere-hours, and watt-hours derived from the charge/discharge cycle tests are studied. Consideration is given to battery voltage and discharge capacity as a function of discharge current, the correlation between energy delivered on a discharge and battery temperature, battery voltage response to pulse discharges, and the voltage-temperature relationship. The data reveal that the bipolar Ni-H battery is applicable to high power systems.

  17. Clinical, Demographic, and Familial Correlates of Bipolar Spectrum Disorders among Offspring of Parents with Bipolar Disorder (United States)

    Goldstein, Benjamin I.; Shamseddeen, Wael; Axelson, David A.; Kalas, Cathy; Monk, Kelly; Brent, David A.; Kupfer, David J.; Birmaher, Boris


    Objective: Despite increased risk, most offspring of parents with bipolar disorder (BP) do not manifest BP. The identification of risk factors for BP among offspring could improve preventive and treatment strategies. We examined this topic in the Pittsburgh Bipolar Offspring Study (BIOS). Method: Subjects included 388 offspring, ages 7-17 years,…

  18. Design of a 1-kWh bipolar nickel hydrogen battery (United States)

    Cataldo, R. L.


    The design of a nickel hydrogen battery utilizing bipolar construction in a common pressure vessel is discussed. Design features are as follows: 40 ampere-hour capacity, 1 kWh stored energy as a 24 cell battery, 1.8 kW delivered in a LEO Cycle and maximum pulse power of 18.0 kW.

  19. Neuroinflammation in bipolar disorder : A [C-11]-(R)-PK11195 positron emission tomography study

    NARCIS (Netherlands)

    Haarman, Bartholomeus C.M.; Riemersma -van der Lek, Rixt; de Groot, Jan Cees; Ruhe, Eric; Klein, Hans C; Zandstra, Tjitske E; Burger, Huibert; Schoevers, Robert A.; de Vries, Erik F.J.; Drexhage, Hemmo A; Nolen, Willem A.; Doorduin, Janine

    Background: The "monocyte-T-cell theory of mood disorders" regards neuroinflammation, i.e. marked activation of microglia, as a driving force in bipolar disorder. Microglia activation can be visualized in vivo using [C-11]-(R)-PK11195 PET. Indirect evidence suggests the hippocampus as a potential

  20. [Circadian markers and genes in bipolar disorder]. (United States)

    Yeim, S; Boudebesse, C; Etain, B; Belliviera, F


    Bipolar disorder is a severe and complex multifactorial disease, characterized by alternance of acute episodes of depression and mania/hypomania, interspaced by euthymic periods. The etiological determinants of bipolar disorder yet, are still poorly understood. For the last 30 years, chronobiology is an important field of investigation to better understand the pathophysiology of bipolar disorder. We conducted a review using Medline, ISI Database, EMBase, PsyInfo up to January 2015, using the following keywords combinations: "mood disorder", "bipolar disorder", "depression", "unipolar disorder", "major depressive disorder", "affective disorder", for psychiatric conditions; and "circadian rhythms", "circadian markers", "circadian gene", "clock gene", "melatonin" for circadian rhythms. The search critera was presence of word in any field of the article. Quantitative and qualitative circadian abnormalities are associated with bipolar disorders both during acute episodes and euthymic periods, suggesting that these altered circadian rhythms may represent biological trait markers of the disorder. These circadian dysfunctions were assessed by various validated tools including polysomnography, actigraphy, sleep diaries, chronotype assessments and blood melatonin/cortisol measures. Other altered endogenous circadian activities have also been reported in bipolar patients, such as hormones secretion, core body temperature or fibroblasts activity. Moreover, these markers were also altered in healthy relatives of bipolar patients, suggesting a degree of heritability. Several genetic association studies have also showed associations between multiple circadian genes and bipolar disorder, such as CLOCK, ARTNL1, GSK3β, PER3, NPAS2, NR1D1, TIMELESS, RORA, RORB, and CSNK1ε. Thus, these circadian gene variants may contribute to the genetic susceptibility of the disease. Furthermore, the study of the clock system may help to better understand some phenotypic aspects like the

  1. Bipolarly stacked electrolyser for energy and space efficient fabrication of supercapacitor electrodes (United States)

    Liu, Xiaojuan; Wu, Tao; Dai, Zengxin; Tao, Keran; Shi, Yong; Peng, Chuang; Zhou, Xiaohang; Chen, George Z.


    Stacked electrolysers with titanium bipolar plates are constructed for electrodeposition of polypyrrole electrodes for supercapacitors. The cathode side of the bipolar Ti plates are pre-coated with activated carbon. In this new design, half electrolysis occurs which significantly lowers the deposition voltage. The deposited electrodes are tested in a symmetrical unit cell supercapacitor and an asymmetrical supercapacitor stack. Both devices show excellent energy storage performances and the capacitance values are very close to the design value, suggesting a very high current efficiency during the electrodeposition. The electrolyser stack offers multi-fold benefits for preparation of conducting polymer electrodes, i.e. low energy consumption, facile control of the electrode capacitance and simultaneous preparation of a number of identical electrodes. Therefore, the stacked bipolar electrolyser is a technology advance that offers an engineering solution for mass production of electrodeposited conducting polymer electrodes for supercapacitors.

  2. Decision making in euthymic bipolar I and bipolar II disorders. (United States)

    Martino, D J; Strejilevich, S A; Torralva, T; Manes, F


    The main aim of this study was to compare a large population of patients with bipolar disorder (BD) types I and II strictly defined as euthymic with healthy controls on measures of decision making. An additional aim was to compare performance on a decision-making task between patients with and without a history of suicide attempt. Eighty-five euthymic patients with BD-I or BD-II and 34 healthy controls were included. All subjects completed tests to assess verbal memory, attention and executive functions, and a decision-making paradigm (the Iowa Gambling Task, IGT). Both groups of patients had worse performance than healthy controls on measures of verbal memory, attention and executive function. No significant differences were found between BD-I, BD-II and healthy controls on measures of decision making. By contrast, patients with a history of suicide attempt had lower performance in the IGT than patients without a history of suicide attempt. Patients with euthymic BD-I and BD-II had intact decision-making abilities, suggesting that this does not represent a reliable trait marker of the disorder. In addition, our results provide further evidence of an association between impairments in decision making and vulnerability to suicidal behavior.

  3. The International Society for Bipolar Disorders (ISBD) Task Force Report on Antidepressant Use in Bipolar Disorders (United States)

    Pacchiarotti, Isabella; Bond, David J.; Baldessarini, Ross J.; Nolen, Willem A.; Grunze, Heinz; Licht, Rasmus W.; Post, Robert M.; Berk, Michael; Goodwin, Guy M.; Sachs, Gary S.; Tondo, Leonardo; Findling, Robert L.; Youngstrom, Eric A.; Tohen, Mauricio; Undurraga, Juan; González-Pinto, Ana; Goldberg, Joseph F.; Yildiz, Ayşegül; Altshuler, Lori L.; Calabrese, Joseph R.; Mitchell, Philip B.; Thase, Michael E.; Koukopoulos, Athanasios; Colom, Francesc; Frye, Mark A.; Malhi, Gin S.; Fountoulakis, Konstantinos N.; Vázquez, Gustavo; Perlis, Roy H.; Ketter, Terence A.; Cassidy, Frederick; Akiskal, Hagop; Azorin, Jean-Michel; Valentí, Marc; Mazzei, Diego Hidalgo; Lafer, Beny; Kato, Tadafumi; Mazzarini, Lorenzo; Martínez-Aran, Anabel; Parker, Gordon; Souery, Daniel; Özerdem, Ayşegül; McElroy, Susan L.; Girardi, Paolo; Bauer, Michael; Yatham, Lakshmi N.; Zarate, Carlos A.; Nierenberg, Andrew A.; Birmaher, Boris; Kanba, Shigenobu; El-Mallakh, Rif S.; Serretti, Alessandro; Rihmer, Zoltan; Young, Allan H.; Kotzalidis, Georgios D.; MacQueen, Glenda M.; Bowden, Charles L.; Ghaemi, S. Nassir; Lopez-Jaramillo, Carlos; Rybakowski, Janusz; Ha, Kyooseob; Perugi, Giulio; Kasper, Siegfried; Amsterdam, Jay D.; Hirschfeld, Robert M.; Kapczinski, Flávio; Vieta, Eduard


    Objective The risk-benefit profile of antidepressant medications in bipolar disorder is controversial. When conclusive evidence is lacking, expert consensus can guide treatment decisions. The International Society for Bipolar Disorders (ISBD) convened a task force to seek consensus recommendations on the use of antidepressants in bipolar disorders. Method An expert task force iteratively developed consensus through serial consensus-based revisions using the Delphi method. Initial survey items were based on systematic review of the literature. Subsequent surveys included new or reworded items and items that needed to be rerated. This process resulted in the final ISBD Task Force clinical recommendations on antidepressant use in bipolar disorder. Results There is striking incongruity between the wide use of and the weak evidence base for the efficacy and safety of antidepressant drugs in bipolar disorder. Few well-designed, long-term trials of prophylactic benefits have been conducted, and there is insufficient evidence for treatment benefits with antidepressants combined with mood stabilizers. A major concern is the risk for mood switch to hypomania, mania, and mixed states. Integrating the evidence and the experience of the task force members, a consensus was reached on 12 statements on the use of antidepressants in bipolar disorder. Conclusions Because of limited data, the task force could not make broad statements endorsing antidepressant use but acknowledged that individual bipolar patients may benefit from antidepressants. Regarding safety, serotonin reuptake inhibitors and bupropion may have lower rates of manic switch than tricyclic and tetracyclic antidepressants and norepinephrine-serotonin reuptake inhibitors. The frequency and severity of antidepressant-associated mood elevations appear to be greater in bipolar I than bipolar II disorder. Hence, in bipolar I patients antidepressants should be prescribed only as an adjunct to mood-stabilizing medications

  4. Depolarization Ratio Profiles Calibration and Observations of Aerosol and Cloud in the Tibetan Plateau Based on Polarization Raman Lidar

    Directory of Open Access Journals (Sweden)

    Guangyao Dai


    Full Text Available A brief description of the Water vapor, Cloud and Aerosol Lidar (WACAL system is provided. To calibrate the volume linear depolarization ratio, the concept of “ Δ 90 ° -calibration” is applied in this study. This effective and accurate calibration method is adjusted according to the design of WACAL. Error calculations and analysis of the gain ratio, calibrated volume linear depolarization ratio and particle linear depolarization ratio are provided as well. In this method, the influences of the gain ratio, the rotation angle of the plane of polarization and the polarizing beam splitter are discussed in depth. Two groups of measurements with half wave plate (HWP at angles of (0 ° , 45 ° and (22.5 ° , −22.5 ° are operated to calibrate the volume linear depolarization ratio. Then, the particle linear depolarization ratios measured by WACAL and CALIOP (the Cloud-Aerosol Lidar with Orthogonal Polarization during the simultaneous observations were compared. Good agreements are found. The calibration method was applied in the third Tibetan Plateau Experiment of Atmospheric Sciences (TIPEX III in 2013 and 2014 in China. Vertical profiles of the particle depolarization ratio of clouds and aerosol in the Tibetan Plateau were measured with WACAL in Litang (30.03° N, 100.28° E, 3949 m above sea level (a.s.l. in 2013 and Naqu (31.48° N, 92.06° E, 4508 m a.s.l. in 2014. Then an analysis on the polarizing properties of the aerosol, clouds and cirrus over the Tibetan Plateau is provided. The particle depolarization ratio of cirrus clouds varies from 0.36 to 0.52, with a mean value of 0.44 ± 0.04. Cirrus clouds occurred between 5.2 and 12 km above ground level (a.g.l.. The cloud thickness ranges from 0.12 to 2.55 km with a mean thickness of 1.22 ± 0.70 km. It is found that the particle depolarization ratio of cirrus clouds become larger as the height increases. However, the increase rate of the particle depolarization ratio becomes smaller as

  5. Dielectric relaxation of 2-ethyl-1-hexanol around the glass transition by thermally stimulated depolarization currents. (United States)

    Arrese-Igor, S; Alegría, A; Colmenero, J


    We explore new routes for characterizing the Debye-like and α relaxation in 2-ethyl-1-hexanol (2E1H) monoalcohol by using low frequency dielectric techniques including thermally stimulated depolarization current (TSDC) techniques and isothermal depolarization current methods. In this way, we have improved the resolution of the overlapped processes making it possible the analysis of the data in terms of a mode composition as expected for a chain-like response. Furthermore the explored ultralow frequencies enabled to study dynamics at relatively low temperatures close to the glass transition (Tg). Results show, on the one hand, that Debye-like and α relaxation timescales dramatically approach to each other upon decreasing temperature to Tg. On the other hand, the analysis of partial polarization TSDC data confirms the single exponential character of the Debye-like relaxation in 2E1H and rules out the presence of Rouse type modes in the scenario of a chain-like response. Finally, on crossing the glass transition, the Debye-like relaxation shows non-equilibrium effects which are further emphasized by aging treatment and would presumably emerge as a result of the arrest of the structural relaxation below Tg.

  6. Stability and morphology of Ag nanoplatelets probed by depolarized dynamic light scattering (United States)

    Zimbone, M.; Contino, A.; Maccarrone, G.; Musumeci, P.; Lo Faro, M. J.; Calcagno, L.


    The stability of silver nanoplatelet (NP) suspensions prepared with different concentrations of trisodium citrate (TSC) was studied by depolarized dynamic light scattering (DDLS) and UV–vis spectrometry. The morphology of the nanoparticles, as well as the color and stability of the sols, are tuned by the concentration of the capping agent. The nanoparticles prepared with high TSC concentration (>10‑4 M) are blue triangular NPs showing a slight truncation of the tips with aging. When low TSC concentrations are used, the color of the sols changes from blue to yellow with aging time and a strong modification of the morphology occurs: the nanoparticle shape changes from triangular to spherical. Remarkably, they show a high degree of anisotropy. The aging process was followed by the UV–vis spectra and by measuring the rotational diffusion coefficient by DDLS, providing information on the nanoparticle size and shape evolution. The high intensity of depolarized signal and the high value of rotational diffusion coefficient suggest that the aging process increases the thickness and the roughness of the nanoparticles

  7. T-matrix modeling of linear depolarization by morphologically complex soot and soot-containing aerosols

    International Nuclear Information System (INIS)

    Mishchenko, Michael I.; Liu, Li; Mackowski, Daniel W.


    We use state-of-the-art public-domain Fortran codes based on the T-matrix method to calculate orientation and ensemble averaged scattering matrix elements for a variety of morphologically complex black carbon (BC) and BC-containing aerosol particles, with a special emphasis on the linear depolarization ratio (LDR). We explain theoretically the quasi-Rayleigh LDR peak at side-scattering angles typical of low-density soot fractals and conclude that the measurement of this feature enables one to evaluate the compactness state of BC clusters and trace the evolution of low-density fluffy fractals into densely packed aggregates. We show that small backscattering LDRs measured with ground-based, airborne, and spaceborne lidars for fresh smoke generally agree with the values predicted theoretically for fluffy BC fractals and densely packed near-spheroidal BC aggregates. To reproduce higher lidar LDRs observed for aged smoke, one needs alternative particle models such as shape mixtures of BC spheroids or cylinders. -- Highlights: ► New superposition T-matrix code is applied to soot aerosols. ► Quasi-Rayleigh side-scattering peak in linear depolarization (LD) is explained. ► LD measurements can be used for morphological characterization of soot aerosols

  8. Bipolar postpartum depression: An update and recommendations. (United States)

    Sharma, Verinder; Doobay, Minakshi; Baczynski, Christine


    Over the past few years there has been a surge of interest in the study of bipolar postpartum depression (PPD); however, questions remain about its prevalence, screening, clinical features, and treatment. Three electronic databases, MEDLINE/PubMed (1966-2016), PsycINFO (1806-2016), and the Cochrane Database of Systematic Reviews, were searched using a combination of the keywords bipolar, depression, postpartum, peripartum, prevalence, screening, diagnosis, treatment, drugs, and psychotherapy. The reference lists of articles identified were also searched. All relevant articles published in English were included. Depending on the population studied, 21.4-54% of women with PPD have a diagnosis of bipolar disorder (BD). Characteristic clinical features include younger age at illness onset, first onset of depression after childbirth, onset immediately after delivery, atypical depressive symptoms, psychotic features, mixed features, and history of BD in first-degree family members. Treatment should be guided by symptom acuity, safety concerns, the patient's response to past treatments, drug tolerability, and breastfeeding preference. In the absence of controlled treatment data, preference should be given to drugs normally indicated for bipolar depression including lithium, quetiapine and lamotrigine. Although antidepressants have been studied in combination with mood stabilizers in bipolar depression, these drugs should be avoided due to likelihood of elevated risk of induction of manic symptoms in the postpartum period. In the postpartum period, bipolar PPD is common, can be differentiated from unipolar PPD, and needs to be identified promptly in order to expedite appropriate treatment. Future studies on pharmacotherapy and psychotherapy should focus on the acute and preventative treatment of bipolar PPD. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Anxiety, stress and perfectionism in bipolar disorder. (United States)

    Corry, Justine; Green, Melissa; Roberts, Gloria; Frankland, Andrew; Wright, Adam; Lau, Phoebe; Loo, Colleen; Breakspear, Michael; Mitchell, Philip B


    Previous reports have highlighted perfectionism and related cognitive styles as a psychological risk factor for stress and anxiety symptoms as well as for the development of bipolar disorder symptoms. The anxiety disorders are highly comorbid with bipolar disorder but the mechanisms that underpin this comorbidity are yet to be determined. Measures of depressive, (hypo)manic, anxiety and stress symptoms and perfectionistic cognitive style were completed by a sample of 142 patients with bipolar disorder. Mediation models were used to explore the hypotheses that anxiety and stress symptoms would mediate relationships between perfectionistic cognitive styles, and bipolar disorder symptoms. Stress and anxiety both significantly mediated the relationship between both self-critical perfectionism and goal attainment values and bipolar depressive symptoms. Goal attainment values were not significantly related to hypomanic symptoms. Stress and anxiety symptoms did not significantly mediate the relationship between self-critical perfectionism and (hypo)manic symptoms. 1. These data are cross-sectional; hence the causality implied in the mediation models can only be inferred. 2. The clinic patients were less likely to present with (hypo)manic symptoms and therefore the reduced variability in the data may have contributed to the null findings for the mediation models with (hypo) manic symptoms. 3. Those patients who were experiencing current (hypo)manic symptoms may have answered the cognitive styles questionnaires differently than when euthymic. These findings highlight a plausible mechanism to understand the relationship between bipolar disorder and the anxiety disorders. Targeting self-critical perfectionism in the psychological treatment of bipolar disorder when there is anxiety comorbidity may result in more parsimonious treatments. © 2013 Published by Elsevier B.V.

  10. Big data for bipolar disorder. (United States)

    Monteith, Scott; Glenn, Tasha; Geddes, John; Whybrow, Peter C; Bauer, Michael


    The delivery of psychiatric care is changing with a new emphasis on integrated care, preventative measures, population health, and the biological basis of disease. Fundamental to this transformation are big data and advances in the ability to analyze these data. The impact of big data on the routine treatment of bipolar disorder today and in the near future is discussed, with examples that relate to health policy, the discovery of new associations, and the study of rare events. The primary sources of big data today are electronic medical records (EMR), claims, and registry data from providers and payers. In the near future, data created by patients from active monitoring, passive monitoring of Internet and smartphone activities, and from sensors may be integrated with the EMR. Diverse data sources from outside of medicine, such as government financial data, will be linked for research. Over the long term, genetic and imaging data will be integrated with the EMR, and there will be more emphasis on predictive models. Many technical challenges remain when analyzing big data that relates to size, heterogeneity, complexity, and unstructured text data in the EMR. Human judgement and subject matter expertise are critical parts of big data analysis, and the active participation of psychiatrists is needed throughout the analytical process.

  11. Bipolar pulse generator for intense pulsed ion beam accelerator

    International Nuclear Information System (INIS)

    Ito, H.; Igawa, K.; Kitamura, I.; Masugata, K.


    A new type of pulsed ion beam accelerator named ''bipolar pulse accelerator'' (BPA) has been proposed in order to improve the purity of intense pulsed ion beams. To confirm the principle of the BPA, we developed a bipolar pulse generator for the bipolar pulse experiment, which consists of a Marx generator and a pulse forming line (PFL) with a rail gap switch on its end. In this article, we report the first experimental result of the bipolar pulse and evaluate the electrical characteristics of the bipolar pulse generator. When the bipolar pulse generator was operated at 70% of the full charge condition of the PFL, the bipolar pulse with the first (-138 kV, 72 ns) and the second pulse (+130 kV, 70 ns) was successfully obtained. The evaluation of the electrical characteristics indicates that the developed generator can produce the bipolar pulse with fast rise time and sharp reversing time

  12. Application of Bipolar Fuzzy Sets in Graph Structures

    Directory of Open Access Journals (Sweden)

    Muhammad Akram


    Full Text Available A graph structure is a useful tool in solving the combinatorial problems in different areas of computer science and computational intelligence systems. In this paper, we apply the concept of bipolar fuzzy sets to graph structures. We introduce certain notions, including bipolar fuzzy graph structure (BFGS, strong bipolar fuzzy graph structure, bipolar fuzzy Ni-cycle, bipolar fuzzy Ni-tree, bipolar fuzzy Ni-cut vertex, and bipolar fuzzy Ni-bridge, and illustrate these notions by several examples. We study ϕ-complement, self-complement, strong self-complement, and totally strong self-complement in bipolar fuzzy graph structures, and we investigate some of their interesting properties.

  13. Cardiovascular risk factors in outpatients with bipolar disorder

    NARCIS (Netherlands)

    Klumpers, U.M.H.; Boom, K.; Janssen, F.M.G.; Tulen, J.H.M.; Loonen, Anton J. M.


    Background: The mortality due to cardiovascular diseases in bipolar patients is much higher than in the general population. It is unclear whether lithium treatment contributes to this cardiovascular morbidity. Methods: The cardiovascular risk factors in outpatients with bipolar disorder on

  14. Cytokines in bipolar disorder vs. healthy control subjects

    DEFF Research Database (Denmark)

    Munkholm, Klaus; Braüner, Julie Vestergaard; Kessing, Lars Vedel


    Bipolar disorder may be associated with peripheral immune system dysfunction; however, results in individual studies are conflicting. Our aim was to systematically review evidence of peripheral cytokine alterations in bipolar disorder integrating findings from various affective states....

  15. Assessment of subjective and objective cognitive function in bipolar disorder

    DEFF Research Database (Denmark)

    Demant, Kirsa M; Vinberg, Maj; Kessing, Lars V


    Cognitive dysfunction is prevalent in bipolar disorder (BD). However, the evidence regarding the association between subjective cognitive complaints, objective cognitive performance and psychosocial function is sparse and inconsistent. Seventy seven patients with bipolar disorder who presented...

  16. Smartphone-based objective monitoring in bipolar disorder

    DEFF Research Database (Denmark)

    Faurholt-Jepsen, Maria; Bauer, Michael; Kessing, Lars Vedel


    , anxiety, substance abuse, eating disorder, schizophrenia and bipolar disorder have been developed and used. The present paper presents the status and findings from studies using automatically generated objective smartphone data in the monitoring of bipolar disorder, and addresses considerations...

  17. Immune activation by casein dietary antigens in bipolar disorder

    NARCIS (Netherlands)

    Severance, E.G.; Dupont, D.; Dickerson, F.B.; Stallings, C.R.; Origoni, A.E.; Krivogorsky, B.; Yang, S.; Haasnoot, W.; Yolken, R.H.


    Objectives: Inflammation and other immune processes are increasingly linked to psychiatric diseases. Antigenic triggers specific to bipolar disorder are not yet defined. We tested whether antibodies to bovine milk caseins were associated with bipolar disorder, and whether patients recognized

  18. Bipolar disorder: an update | Outhoff | South African Family Practice

    African Journals Online (AJOL)

    Bipolar disorder, characterised by alternating discrete episodes of (hypo)mania and depression, provides unique diagnostic and treatment challenges. Updated diagnostic (DSM-5) and current pharmacological treatment recommendations are briefly reviewed here. Keywords: bipolar disorder; diagnosis; evidence-based ...

  19. Parametric and cycle tests of a 40-A-hr bipolar nickel-hydrogen battery (United States)

    Cataldo, R. L.


    A series of tests was performed to characterize battery performance relating to certain operating parameters which included charge current, discharge current, temperature and pressure. The parameters were varied to confirm battery design concepts and to determine optimal operating conditions. Spacecraft power requirements are constantly increasing. Special spacecraft such as the Space Station and platforms will require energy storage systems of 130 and 25 kWh, respectively. The complexity of these high power systems will demand high reliability, and reduced mass and volume. A system that uses batteries for storage will require a cell count in excess of 400 units. These cell units must then be assembled into several batteries with over 100 cells in a series connected string. In an attempt to simplify the construction of conventional cells and batteries, the NASA Lewis Research Center battery systems group initiated work on a nickel-hydrogen battery in a bipolar configuration in early 1981. Features of the battery with this bipolar construction show promise in improving both volumetric and gravimetric energy densities as well as thermal management. Bipolar construction allows cooling in closer proximity to the cell components, thus heat removal can be accomplished at a higher rejection temperature than conventional cell designs. Also, higher current densities are achievable because of low cell impedance. Lower cell impedance is achieved via current flow perpendicular to the electrode face, thus reducing voltage drops in the electrode grid and electrode terminals tabs.

  20. Comorbid medical illness in bipolar disorder. (United States)

    Forty, Liz; Ulanova, Anna; Jones, Lisa; Jones, Ian; Gordon-Smith, Katherine; Fraser, Christine; Farmer, Anne; McGuffin, Peter; Lewis, Cathryn M; Hosang, Georgina M; Rivera, Margarita; Craddock, Nick


    Individuals with a mental health disorder appear to be at increased risk of medical illness. To examine rates of medical illnesses in patients with bipolar disorder (n = 1720) and to examine the clinical course of the bipolar illness according to lifetime medical illness burden. Participants recruited within the UK were asked about the lifetime occurrence of 20 medical illnesses, interviewed using the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and diagnosed according to DSM-IV criteria. We found significantly increased rates of several medical illnesses in our bipolar sample. A high medical illness burden was associated with a history of anxiety disorder, rapid cycling mood episodes, suicide attempts and mood episodes with a typically acute onset. Bipolar disorder is associated with high rates of medical illness. This comorbidity needs to be taken into account by services in order to improve outcomes for patients with bipolar disorder and also in research investigating the aetiology of affective disorder where shared biological pathways may play a role. Royal College of Psychiatrists.

  1. Bipolar magnetic semiconductor in silicene nanoribbons

    International Nuclear Information System (INIS)

    Farghadan, Rouhollah


    Highlights: • A new electronic phase for silicene nanoribbon in the presence of electric and magnetic fields. • Bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps in silicene. • Robust bipolar magnetic semiconductor features in a rough silicene. • Perfect and reversible spin polarization in silicene nanoribbon junctions. - Abstract: A theoretical study was presented on generation of spin polarization in silicene nanoribbons using the single-band tight-binding approximation and the non-equilibrium Green’s function formalism. We focused on the effect of electric and exchange magnetic fields on the spin-filter capabilities of zigzag-edge silicene nanoribbons in the presence of the intrinsic spin-orbit interaction. The results show that a robust bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps can be obtained when exchange magnetic and electric field strengths are both larger than the intrinsic spin-orbit interaction. Therefore, zigzag silicene nanoribbons could act as bipolar and perfect spin filter devices with a large spin-polarized current and a reversible spin polarization in the vicinity of the Fermi energy. We also investigated the effect of edge roughness and found that the bipolar magnetic semiconductor features are robust against edge disorder in silicene nanoribbon junctions. These results may be useful in multifunctional spin devices based on silicene nanoribbons.

  2. [Drug Abuse Comorbidity in Bipolar Disorder]. (United States)

    Ortiz, Óscar Medina


    Drug use among patients with bipolar disorder is greater than the one observed in the general population; psychotic episodes are likely to occur after consumption. This has implications in the prevention, etiology, management, and treatment of the disease. Bipolar disorder pathology is likely to have positive response to pharmacological treatment. Therefore, identifying the strategies with better results to be applied in these patients is fundamental for psychiatrists and primary care physicians. Review literature in order to determine the prevalence and characteristics of drug abuse in patients with bipolar disorder and establish the pharmacological strategies that have produced better results. Literature review. A great variety of studies demonstrate the relationship between bipolar disorder and drug use disorder. These patients are hospitalized more frequently, have an earlier onset of the disease, and present a larger number of depressive episodes and suicide attempts which affect the course of the disease. The drug with better results in the treatment of these patients is Divalproate. Satisfactory results have been also obtained with other mood stabilizers such as carbamazepine, lamotrigine, and the antipsychotic aripiprazole. Substance abuse is present in a large number of patients with bipolar disorder. The Divalproate is the drug that has shown better results in the studies. Copyright © 2012 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

  3. Family History in Patients with Bipolar Disorder. (United States)

    Özdemir, Osman; Coşkun, Salih; Aktan Mutlu, Elif; Özdemir, Pınar Güzel; Atli, Abdullah; Yilmaz, Ekrem; Keskin, Sıddık


    In this study, we aimed to better understand the genetic transmission of bipolar disorder by examining the family history of patients. Sixty-three patients with bipolar disorder and their families were included. The final sample comprised 156 bipolar patients and their family members. An inclusion criterion was the presence of bipolar disorder history in the family. The diagnosis of other family members was confirmed by analyzing their files, hospital records, and by calling them to the hospital. Sixty-five patients were women (41.6%) and 91 were men (58.3%) (ratio of men/women: 1.40). When analyzing the results in terms of the transition of disease from the mother's or father's side, similar results were obtained: 25 patients were from the mother's side and 25 patients were from the father's side in 63 cases. The results of our study support the fact that a significant relationship exists between the degree of kinship and the heritability of bipolar disorder and, furthermore, that the effect of the maternal and paternal sides is similar on the transmission of genetic susceptibility.

  4. Bipolar magnetic semiconductor in silicene nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Farghadan, Rouhollah, E-mail:


    Highlights: • A new electronic phase for silicene nanoribbon in the presence of electric and magnetic fields. • Bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps in silicene. • Robust bipolar magnetic semiconductor features in a rough silicene. • Perfect and reversible spin polarization in silicene nanoribbon junctions. - Abstract: A theoretical study was presented on generation of spin polarization in silicene nanoribbons using the single-band tight-binding approximation and the non-equilibrium Green’s function formalism. We focused on the effect of electric and exchange magnetic fields on the spin-filter capabilities of zigzag-edge silicene nanoribbons in the presence of the intrinsic spin-orbit interaction. The results show that a robust bipolar magnetic semiconductor with controllable spin-flip and spin-conserved gaps can be obtained when exchange magnetic and electric field strengths are both larger than the intrinsic spin-orbit interaction. Therefore, zigzag silicene nanoribbons could act as bipolar and perfect spin filter devices with a large spin-polarized current and a reversible spin polarization in the vicinity of the Fermi energy. We also investigated the effect of edge roughness and found that the bipolar magnetic semiconductor features are robust against edge disorder in silicene nanoribbon junctions. These results may be useful in multifunctional spin devices based on silicene nanoribbons.

  5. The Dutch Bipolar Offspring Study: 12-Year Follow-Up


    Mesman, Esther; Nolen, Willem A.; Reichart, Catrien G.; Wals, Marjolein; Hillegers, Manon N. J.


    Objective: Offspring of bipolar parents have a genetically increased risk of developing mood disorders. In a longitudinal study, the authors followed a bipolar offspring cohort from adolescence into adulthood to determine the onset, prevalence, and early course of mood disorders and other psychopathology. Method: The Dutch bipolar offspring cohort is a fixed cohort initiated in 1997 (N=140; age range at baseline, 12-21 years). Bipolar offspring were psychiatrically evaluated at baseline and a...

  6. Rumination in bipolar disorder: evidence for an unquiet mind


    Ghaznavi, Sharmin; Deckersbach, Thilo


    Abstract Depression in bipolar disorder has long been thought to be a state characterized by mental inactivity. However, recent research demonstrates that patients with bipolar disorder engage in rumination, a form of self-focused repetitive cognitive activity, in depressed as well as in manic states. While rumination has long been associated with depressed states in major depressive disorder, the finding that patients with bipolar disorder ruminate in manic states is unique to bipolar disord...

  7. LAP-ND: a new instrument for vector polarization analysis and neutron depolarization measurements at FRJ-2

    International Nuclear Information System (INIS)

    Ioffe, Alexander; Bussmann, Klaus; Dohmen, Ludwig; Axelrod, Leonid; Gordeev, Gennadi; Brueckel, Thomas


    The method of vector analysis of the neutron polarization allows for the determination of both the magnitude and the direction of the magnetization vector in the sample. A directional distribution of the magnetization in a sample results in a spread of the direction of the polarization vector in space and thus in the depolarization of the incident beam. A new neutron depolarization set up is installed at the research reactor FRJ-2 of the Forschungszentrum Juelich. The main feature of the set up is the use of rather long wavelength, λ=(4-6.5) A, neutrons thus allowing for a significant increase in the sensitivity of depolarization measurements. The set up uses a non-cryogenic zero-field sample chamber with the residual magnetic field of about 1 mG. It will be used for the determination of the sample magnetization at mesoscopic and macroscopic levels and for the study of magnetic phase transitions, magnetic nanostructures, magnetic glasses, etc

  8. Contribution of corner reflections from oriented ice crystals to backscattering and depolarization characteristics for off-zenith lidar profiling (United States)

    Borovoi, Anatoli G.; Konoshonkin, Alexander V.; Kustova, Natalia V.; Veselovskii, Igor A.


    Backscattering Mueller matrix and the depolarization and color ratios for quasi-horizontally oriented hexagonal ice plates have been calculated within the framework of the physical optics approximation. In the case of a tilted lidar, the dependence of the color and depolarization ratios on polarization of the incident light has been analyzed. It is shown that the corner reflection effect inherent to the pristine hexagonal ice crystals results in sharp peaks of both the backscattering cross section and depolarization ratio at the lidar tilts of about 30° off zenith. The experimental results obtained recently by Veselovskii et al. [13] at the lidar tilt of 43° have been interpreted as a partial manifestation of the corner reflection effect. The retrieval of the vertical profile of the ice crystal fraction consisting of quasi-horizontally oriented hexagonal plates has been demonstrated.

  9. LAP-ND: a new instrument for vector polarization analysis and neutron depolarization measurements at FRJ-2

    Energy Technology Data Exchange (ETDEWEB)

    Ioffe, Alexander; Bussmann, Klaus; Dohmen, Ludwig; Axelrod, Leonid; Gordeev, Gennadi; Brueckel, Thomas


    The method of vector analysis of the neutron polarization allows for the determination of both the magnitude and the direction of the magnetization vector in the sample. A directional distribution of the magnetization in a sample results in a spread of the direction of the polarization vector in space and thus in the depolarization of the incident beam. A new neutron depolarization set up is installed at the research reactor FRJ-2 of the Forschungszentrum Juelich. The main feature of the set up is the use of rather long wavelength, {lambda}=(4-6.5) A, neutrons thus allowing for a significant increase in the sensitivity of depolarization measurements. The set up uses a non-cryogenic zero-field sample chamber with the residual magnetic field of about 1 mG. It will be used for the determination of the sample magnetization at mesoscopic and macroscopic levels and for the study of magnetic phase transitions, magnetic nanostructures, magnetic glasses, etc.

  10. Risk factors for suicide among children and youths with bipolar spectrum and early bipolar disorder. (United States)

    Rajewska-Rager, Aleksandra; Sibilski, Piotr; Lepczyńska, Natalia


    In recent years much attention has been given to determine risk factors for suicide among adults with bipolar disorder. Such studies concerning children and youths, which would also take into account the specificity of the developmental age, are still too few. The ability to identify risk factors for children and youths with mood disorders, as well as the possibility to monitor them, is an essential element in preventing suicidal behaviours. Previous studies have clearly indicated that in the group of patients with an early onset of the bipolar disorder the occurrence of suicidal thoughts and intentions were significantly increased. Identifying the risk of suicide is hindered further by the complexity of the phenomenon, which is a compound interaction of various factors: biological, environmental, sociological, psychological and clinical. This is especially true with young adults suffering from mental illness and presenting a number of other psychopathological symptoms. The following paper introduces and reviews the results of current studies, which analysed the risk factors for suicide among children and youths with bipolar spectrum or already diagnosed with bipolar disorder. For this purpose we conducted the overview of recent years literature available in PubMed/MEDLINE database, including the following search criteria: early onset bipolar disorder, bipolar disorder in children and young people, the spectrum of bipolar disorder, and suicidal ideation, suicidal intent, suicide.

  11. On Bipolar Valued Fuzzy k-Ideals in Hermirings

    International Nuclear Information System (INIS)

    Mahmood, T.; Ejaz, A.


    In this paper we discuss some results associated with bipolar valued fuzzy k -ideals of hermirings. We also define bipolar valued fuzzy k-intrinsic product and characterize k-hemiregular hermirings by using their bipolar valued fuzzy k -ideals. (author)

  12. Dose enhancement effects of X ray radiation in bipolar transistors

    International Nuclear Information System (INIS)

    Chen Panxun


    The author has presented behaviour degradation and dose enhancement effects of bipolar transistors in X ray irradiation environment. The relative dose enhancement factors of X ray radiation were measured in bipolar transistors by the experiment methods. The mechanism of bipolar device dose enhancement was investigated

  13. Family Functioning and the Course of Adolescent Bipolar Disorder (United States)

    Sullivan, Aimee E.; Judd, Charles M.; Axelson, David A.; Miklowitz, David J.


    The symptoms of bipolar disorder affect and are affected by the functioning of family environments. Little is known, however, about the stability of family functioning among youth with bipolar disorder as they cycle in and out of mood episodes. This study examined family functioning and its relationship to symptoms of adolescent bipolar disorder,…

  14. Depolarization changes during acute myocardial ischemia by evaluation of QRS slopes: standard lead and vectorial approach. (United States)

    Romero, Daniel; Ringborn, Michael; Laguna, Pablo; Pahlm, Olle; Pueyo, Esther


    Diagnosis and risk stratification of patients with acute coronary syndromes can be improved by adding information from the depolarization phase (QRS complex) to the conventionally used ST-T segment changes. In this study, ischemia-induced changes in the main three slopes of the QRS complex, upward ( ℑ(US)) and downward ( ℑ(DS) ) slopes of the R wave as well as the upward ( ℑ(TS)) slope of the terminal S wave, were evaluated as to represent a robust measure of pathological changes within the depolarization phase. From ECG recordings both in a resting state (control recordings) and during percutaneous coronary intervention (PCI)-induced transmural ischemia, we developed a method for quantification of ℑ(US), ℑ(DS), and ℑ(TS) that incorporates dynamic ECG normalization so as to improve the sensitivity in the detection of ischemia-induced changes. The same method was also applied on leads obtained by projection of QRS loops onto their dominant directions. We show that ℑ(US), ℑ(DS), and ℑ(TS) present high stability in the resting state, thus providing a stable reference for ischemia characterization. Maximum relative factors of change ( ℜ(ℑ)) during PCI were found in leads derived from the QRS loop, reaching 10.5 and 13.7 times their normal variations in the control for ℑ(US) and ℑ(DS), respectively. For standard leads, the relative factors of change were 6.01 and 9.31. The ℑ(TS) index presented a similar behavior to that of ℑ(DS). The timing for the occurrence of significant changes in ℑ(US) and ℑ(DS) varied with lead, ranging from 30 s to 2 min after initiation of coronary occlusion. In the present ischemia model, relative ℑ(DS) changes were smaller than ST changes in most leads, however with only modest correlation between the two indices, suggesting they present different information about the ischemic process. We conclude that QRS slopes offer a robust tool for evaluating depolarization changes during myocardial ischemia.

  15. Characterization testing of a 40 Ahr bipolar nickel hydrogen battery (United States)

    Brewer, Jeffrey C.; Manzo, Michelle A.; Gahn, Randall F.


    In a continuing effort to develop NiH2 bipolar technology to a point where it can be used efficiently in space flight, testing of a second 40 Ahr, 10-cell bipolar battery has begun. This battery has undergone extensive characterization testing to determine the effects of such operating parameters as charge and discharge rates, temperature, and pressure. The fundamental design of this actively cooled bipolar battery is the same as the first battery. Most of the individual components, however, are from different manufacturers. Different testing procedures as well as certain unique battery characteristics make it difficult to directly compare the two sets of results. In general, the performance of this battery throughout characterization produced expected results. The main differences seen between the first and second batteries occurred during the high-rate discharge portion of the test matrix. The first battery also had poor high-rate discharge results, although better than those of the second battery. Minor changes were made to the battery frame design used for the first battery in an attempt to allow better gas access to the reaction sites for the second build and hopefully improve performance. The changes, however, did not improve the performance of the second battery and could have possibly contributed to the poorer performance that was observed. There are other component differences that could have contributed to the poorer performance of the second battery. The H2 electrode in the second battery was constructed with a Goretex backing which could have limited the high-rate current flow. The gas screen in the second battery had a larger mesh which again could have limited the high-rate current flow. Small scale 2 x 2 batteries are being tested to evaluate the effects of the component variations.

  16. Experimental observation of spontaneous depolarized guided acoustic-wave Brillouin scattering in side cores of a multicore fiber (United States)

    Hayashi, Neisei; Mizuno, Yosuke; Nakamura, Kentaro; Set, Sze Yun; Yamashita, Shinji


    Spontaneous depolarized guided acoustic-wave Brillouin scattering (GAWBS) was experimentally observed in one of the side cores of an uncoated multicore fiber (MCF). The frequency bandwidth in the side core was up to ∼400 MHz, which is 0.5 times that in the central core. The GAWBS spectrum of the side core of the MCF included intrinsic peaks, which had different acoustic resonance frequencies from those of the central core. In addition, the spontaneous depolarized GAWBS in the central/side core was unaffected by that in the other core. These results will lead to the development of polarization/phase modulators using an MCF.

  17. Recovery of slow potentials in AC-coupled electrocorticography: application to spreading depolarizations in rat and human cerebral cortex

    DEFF Research Database (Denmark)

    Hartings, Jed A; Watanabe, Tomas; Dreier, Jens P


    Cortical spreading depolarizations (spreading depressions and peri-infarct depolarizations) are a pathology intrinsic to acute brain injury, generating large negative extracellular slow potential changes (SPCs) that, lasting on the order of minutes, are studied with DC-coupled recordings in animals...... of the inverse filter was validated by its ability to recover both simulated and real low-frequency input test signals. The inverse filter was then applied to AC-coupled ECoG recordings from five patients who underwent invasive monitoring after aneurysmal subarachnoid hemorrhage. For 117 SPCs, the inverse filter...

  18. Ion transport Modeling in a Bipolar Membrane

    International Nuclear Information System (INIS)

    Kim, Jung Soo; Park, Kwang Heon; Kim, Kwang Wook


    The COL(Carbonate-based Oxidative Leaching) process is an environmentally-friendly technique for collecting only uranium from spent fuel with oxidation leaching/ precipitation of carbonate solution. The bipolar membrane used for the electrolyte circulation of the salt used in the COL process is a special form of ion exchange membrane which combines CEM(cation exchange membrane) and AEM(anion exchange membrane). After arranging positive ion exchange layer toward negative terminal and positive ion exchange layer toward positive terminal, then supply electricity, water molecules are decomposed into protons and hydroxyl ions by a strong electric field in the transition region inside bipolar membrane.1) In this study, a theoretical approach to increase the efficiency of Na + and NO3 - ion collecting device using bipolar membrane was taken and simulating using the COMSOL program was tried. The details of results are also discussed

  19. Neuronal migration, apoptosis and bipolar disorder. (United States)

    Uribe, Ezequiel; Wix, Richard


    Bipolar disorder, like the majority of psychiatric disorders, is considered a neurodevelopment disease of neurodevelopment. There is an increased rate of neuronal birth and death during this development period. In the particular case of the processes that determine neuronal death, it is known that those neurons that establish connections have to be removed from the central nervous system. There is a deficit of GABAergic interneurons in the cerebral cortex in bipolar disorder, accompanied by overexpression of proapoptic genes. There is also an alteration in the expression of molecules that mediate in the migration of these neurons and their inclusion in functional synapsis during the foetal stage. The role of these molecules in the neuronal death pathways by apoptosis will be reviewed here in an attempt to establish biological hypotheses of the genesis of bipolar disorder. Copyright © 2011 SEP y SEPB. Published by Elsevier Espana. All rights reserved.

  20. Concurrent hypokalemic periodic paralysis and bipolar disorder

    Directory of Open Access Journals (Sweden)

    Chia-Lin Lin


    Full Text Available Primary periodic paralysis is a rare autosomal dominant disorder of ion-channel dysfunction, manifested by episodic flaccid paresis secondary to abnormal sarcolemma excitability. Membrane destabilization involving Na, K-ATPase has been hypothesized to be a biological etiology of the bipolar disorder (BD and the mechanisms underlying lithium therapy have been linked to it. To date, there has been only one reported case of BD comorbid with periodic paralysis. Herein, we reported another case of concurrent bipolar mania and hypokalemic periodic paralysis (HPP, one special form of periodic paralysis. Consistent with the previous case, our patient responded well to lithium treatment for both bipolar mania and HPP. This might provide some support to the hypothesis that the therapeutic effects of lithium in both BD and HPP could be due to the correction of the underlying common pathophysiology.

  1. Fenomenologia do tempo vivido no transtorno bipolar

    Directory of Open Access Journals (Sweden)

    Virginia Moreira

    Full Text Available Com base na tradição da psicopatologia fenomenológica, este artigo se propõe a contribuir para a compreensão do mundo vivido do paciente bipolar, marcado por uma forte alteração do tempo vivido. Realizamos uma descrição deste tempo vivido significado de forma diferente nas oscilações de humor chamadas de fase maníaca e fase melancólica. Pensado a partir da temporalidade, na fase melancólica, o bipolar parece parar no tempo, não se lança em um devir. Na fase maníaca, o sujeito vive demasiadamente um agora como se tivesse explodido sua biografia. Concluímos que estas fases, ou dois pólos opostos no funcionamento temporal patológico do sofrimento bipolar, constituem fundamentalmente um mesmo mundo vivido.

  2. Genetic structure of personality factors and bipolar disorder in families segregating bipolar disorder. (United States)

    Hare, Elizabeth; Contreras, Javier; Raventos, Henriette; Flores, Deborah; Jerez, Alvaro; Nicolini, Humberto; Ontiveros, Alfonso; Almasy, Laura; Escamilla, Michael


    Bipolar disorder (BPD) has been associated with variations in personality dimensions, but the nature of this relationship has been unclear. In this study, the heritabilities of BPD and the Big Five personality factors and the genetic correlations between BPD and personality factors are reported. The participants in this study were 1073 individuals from 172 families of Mexican or Central American ancestry. Heritabilities and genetic correlations were calculated under a polygenic model using the maximum-likelihood method of obtaining variance components implemented in the SOLAR software package. Heritabilities of 0.49, 0.43, and 0.43 were found for the narrowest phenotype (schizoaffective bipolar and bipolar I), the intermediate phenotype (schizoaffective bipolar, bipolar I, and bipolar II), and the broadest phenotype (schizoaffective bipolar, bipolar I, bipolar II, and recurrent depression), respectively. For the Big Five personality factors, heritabilities were 0.25 for agreeableness, 0.24 for conscientiousness, 0.24 for extraversion, 0.23 for neuroticism, and 0.32 for openness to experience. For the narrowest phenotype, a significant negative correlation (-0.32) with extraversion was found. For the broadest phenotype, negative correlations were found for agreeableness (-0.35), conscientiousness (-0.39), and extraversion (-0.44). A positive correlation (0.37) was found with neuroticism. It is not possible to determine whether aspects of personality are factors in the development of bipolar disorder or vice versa. The short form of the NEO does not provide the ability to examine in detail which facets of extraversion are most closely related to bipolar disorder or to compare our results with studies that have used the long version of the scale. This study establishes a partial genetic basis for the Big Five personality factors in this set of families, while the environmental variances demonstrate that non-genetic factors are also important in their influence on

  3. The miRNome of bipolar disorder. (United States)

    Fries, Gabriel R; Carvalho, Andre F; Quevedo, Joao


    Epigenetic mechanisms have been suggested to play a key role in the pathophysiology of bipolar disorder (BD), among which microRNAs (miRNAs) may be of particular significance according to recent studies. We aimed to summarize miRNA studies in BD to identify consistent findings, limitations, and future directions of this emerging field. We performed a comprehensive search on PUBMED and Medline for studies investigating an association between BD and miRNAs. The included studies report miRNA alterations in postmortem brain tissues and in the periphery, cell culture and preclinical findings, genetic associations, and the effects of medications. Several studies report changes in miRNA expression levels in postmortem brain and in the periphery of patients, although most of the results so far have not been replicated and are not concordant between different populations. Genetic studies also suggest that miRNA genes are located within susceptibility loci of BD, and also a putative role of miRNAs in modulating genes previously shown to confer risk of BD. We did not perform a systematic review of the literature, and miRNAs represent only one facet of the plethora of epigenetic mechanisms that might be involved in BD's pathophysiology. miRNA findings in BD significantly vary between studies, but are consistent to suggest a key role for these molecules in BD's pathophysiology and treatment, particularly miR-34a and miR-137. Accordingly, miRNA might represent important biomarkers of illness to be used in the clinical settings, and potentially also for the development of novel therapeutics for BD in the near future. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. A combined analysis of genome-wide expression profiling of bipolar disorder in human prefrontal cortex. (United States)

    Wang, Jinglu; Qu, Susu; Wang, Weixiao; Guo, Liyuan; Zhang, Kunlin; Chang, Suhua; Wang, Jing


    Numbers of gene expression profiling studies of bipolar disorder have been published. Besides different array chips and tissues, variety of the data processes in different cohorts aggravated the inconsistency of results of these genome-wide gene expression profiling studies. By searching the gene expression databases, we obtained six data sets for prefrontal cortex (PFC) of bipolar disorder with raw data and combinable platforms. We used standardized pre-processing and quality control procedures to analyze each data set separately and then combined them into a large gene expression matrix with 101 bipolar disorder subjects and 106 controls. A standard linear mixed-effects model was used to calculate the differentially expressed genes (DEGs). Multiple levels of sensitivity analyses and cross validation with genetic data were conducted. Functional and network analyses were carried out on basis of the DEGs. In the result, we identified 198 unique differentially expressed genes in the PFC of bipolar disorder and control. Among them, 115 DEGs were robust to at least three leave-one-out tests or different pre-processing methods; 51 DEGs were validated with genetic association signals. Pathway enrichment analysis showed these DEGs were related with regulation of neurological system, cell death and apoptosis, and several basic binding processes. Protein-protein interaction network further identified one key hub gene. We have contributed the most comprehensive integrated analysis of bipolar disorder expression profiling studies in PFC to date. The DEGs, especially those with multiple validations, may denote a common signature of bipolar disorder and contribute to the pathogenesis of disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Three times more days depressed than manic or hypomanic in both bipolar I and bipolar II disorder

    NARCIS (Netherlands)

    Kupka, Ralph W.; Altshuler, Lori L.; Nolen, Willem A.; Suppes, Trisha; Luckenbaugh, David A.; Leverich, Gabriele S.; Frye, Mark A.; Keck, Paul E.; McElroy, Susan L.; Grunze, Heinz; Post, Robert M.

    Objectives: To assess the proportion of time spent in mania, depression and euthymia in a large cohort of bipolar subjects studied longitudinally, and to investigate depression/mania ratios in patients with bipolar I versus bipolar II disorder. Methods: Clinician-adjusted self-ratings of mood were

  6. Alcoholism and anxiety in bipolar illness : Differential lifetime anxiety comorbidity in bipolar I women with and without alcoholism

    NARCIS (Netherlands)

    Levander, Eric; Frye, Mark A.; McElroy, Susan; Suppes, Trisha; Grunze, Heinz; Nolen, Willem A.; Kupka, Ralph; Keck, Paul E.; Leverich, Gabriele S.; Altshuler, Lori L.; Hwang, Sun; Mintz, Jim; Post, Robert M.

    Introduction: This study was undertaken to evaluate the prevalence rate of anxiety comorbidity in bipolar subjects with and without alcohol use disorders (AUD). Methods: Bipolar men and women who entered the Stanley Foundation Bipolar Network (SFBN) underwent a Structured Clinical Interview for

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

    Czech Academy of Sciences Publication Activity Database

    Slezák, Ondřej; Yasuhara, R.; Lucianetti, Antonio; Vojna, David; Mocek, Tomáš


    Roč. 17, č. 6 (2015), s. 1-8, č. článku 065610. ISSN 2040-8978 R&D Projects: GA MŠk ED2.1.00/01.0027; GA MŠk EE2.3.20.0143; GA MŠk EE2.3.30.0057 Grant - others:HILASE(XE) CZ.1.05/2.1.00/01.0027; OP VK 6(XE) CZ.1.07/2.3.00/20.0143; OP VK 4 POSTDOK(XE) CZ.1.07/2.3.00/30.0057 Institutional support: RVO:68378271 Keywords : stress-induced birefringence * thermal depolarization * high-power lasers Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.847, year: 2015

  8. Measurement of the broadening and depolarization of a Gaussian beam to transmit in fog water

    International Nuclear Information System (INIS)

    Serrano, G.; Reynoso, E; Davila, J. A.


    In this paper, we develop a controlled experimental environment in the laboratory, a waterproof camera where it will introduce artificial fog and become a beam of linearly polarized Gaussian laser light, creating sprawl, broadening and depolarization is studied with a system capable of measuring such phenomena. Most studies on dispersion have focused on the lobes of backscattering, however the correct conditions with the incident light beam a substantial fraction of light is scattered in the forward direction forming a widened light lobe. With this light lobe formed could be studied with extreme precision many factors such as the existence of single or multiple scattering and the amount by which this is carried out. This is of great importance in the estimation of lidar returns because these foundations can learn important information such as extinction and backscatter coefficients, particulate pollutants in the atmosphere and thus understand the operation model of nature. (Author)

  9. Study of depolarization of deuteron and proton beams in the Nuclotron ring

    CERN Document Server

    Golubeva, N Y; Kondratenko, A M; Kondratenko, A M; Mikhajlov, V A; Strokovsky, E A


    The scheme for acceleration of polarized deuterons at the Nuclotron accelerator facility includes a cryogenic polarized deuteron source 'Polaris', a 5 MeV/nucl. linac, a superconducting heavy ion synchrotron of a 6 GeV/nucl. energy with 10 s spill slow extraction, thin internal targets and wide net of external beam lines. This scheme also allows one to generate high energy polarized proton and neutron beams with well determined characteristics. There are two principal problems of polarized particle acceleration: to keep spin orientation during beam acceleration and to produce the high ion intensity sufficient for data taking in physics experiments. The first problem is discussed in this paper. The reasons of depolarization effects in the mentioned parts of the Nuclotron have been analysed and four methods of the polarization conserving have been suggested. They are the spin resonance strength compensation increasing of the resonance strength, the betatron tune jump and the spin tune jump. Among their number, ...

  10. Adiabatic Siberian snake turn-on and acceleration through depolarizing resonances

    International Nuclear Information System (INIS)

    Koulsha, A.V.; Anferov, V.A.; Baiod, R.


    The authors plan to install in the IUCF Cooler Ring a rampable partial (30%) Siberian snake to test if the spin polarization is preserved during adiabatic turn-on. They also plan to use this ramped snake to accelerate polarized protons to 370 MeV while passing through two depolarizing resonances. The Siberian snake will consist of two small rampable warm solenoids placed symmetrically on either side of the exciting cold 2 T·m solenoid which would run dc at about 0.5 T·m. Ramping each warm magnet from about -0.25T·m to + 0.25 T·m. Recent experiments showed that turning on the snake in 100 msec at 370 MeV causes no serious beam loss

  11. LEO life tests on a 75 Ah bipolar nickel-hydrogen battery (United States)

    Lenhart, S.; Koehler, C.; Applewhite, A.


    The design, building, and testing of an actively cooled 10-cell 75-Ah bipolar nickel/hydrogen battery are discussed. During the last 1000 cycles, the battery has shown some evidence of elecrical performance degradation. In particular, EOC and EOD voltages have increased and decreased by several millivolts, respectively, and deep discharge capacities to a 1.0 V/cell average cutoff voltage have decreased.

  12. Depolarization in the elastic scattering of 17 MeV polarized protons from 9Be

    International Nuclear Information System (INIS)

    Baker, M.P.


    The Wolfenstein depolarization parameter D(theta) was measured for the elastic scattering of 17-MeV protons from 9 Be at laboratory scattering angles between 70 0 and 120 0 in 10 0 steps with uncertainties ranging from 0.05 to 0.07. The reaction was initiated by polarized protons and the polarization of those protons elastically scattered by the 9 Be analyzed using a high-resolution, silicon polarimeter. Several of the measured values of D(theta) differed significantly from unity, indicating non-zero probability for proton spin-flip in the elastic scattering process. Theoretical estimates of the depolarization-parameter angular distribution have been made using a multipole expansion of the elastic-scattering amplitude in terms of the amount of angular momentum transferred to the target nucleus during the scattering process. Here the J = 0, 1 and 2 contributions to the scattering amplitude have been explicitly treated for the scattering from 9 Be(I = 3 / 2 ). The J = 0 terms are calculated using the standard, spherical optical-model. The J = 1 and 2 terms can be calculated using DWBA. Both spherical and tensor forms are considered for the J = 1 interaction. The spin-flip probabilities predicted assuming reasonable strengths for the J = 1 potentials are much smaller than those observed experimentally. The J = 2 contribution to the spin-flip probability is calculated assuming a rotational model for 9 Be. Predictions of the J = 2, elastic spin-flip probability are substantially larger than the predictions for the J = 1 contribution and are in rough agreement with the present data. The results of recent coupled-channels calculations also support the conclusion that large elastic spin-flip probabilities can be produced by the J = 2 term in the elastic scattering amplitude

  13. Depolarization of the electron spin in storage rings by nonlinear spin-orbit coupling

    International Nuclear Information System (INIS)

    Kewisch, J.


    Electrons and positrons which circulate in the storage ring are polarized at the emission of synchrotron radiation by the so called Sokolov-Ternov effect. This polarization is on the one hand of large interest for the study of the weak interaction, on the other hand it can be used for the accurate measurement of the beam energy and by this of the mass of elementary particles. The transverse and longitudinal particle vibrations simultaneously excited by the synchrotron radiation however can effect that this polarization is destroyed. This effect is called spin-orbit coupling. For the calculation of the spin-orbit coupling the computer program SITROS was written. This program is a tracking program: The motion of some sample particles and their spin vectors are calculated for some thousand circulations. From this the mean depolarization and by extrapolation the degree of polarization of the equilibrium state is determined. Contrarily to the known program SLIM which is based on perturbational calculations in SITROS the nonlinear forces in the storage ring can be regarded. By this the calculation of depolarizing higher order resonances is made possible. In this thesis the equations of motion for the orbital and spin motion of the electrons are derived which form the base for the program SITROS. The functions of the program and the approximations necessary for the saving of calculational time are explained. The comparison of the SITROS results with the measurement results obtained at the PETRA storage ring shows that the SITROS program is a useful means for the planning and calculation of storage rings with polarized electron beams. (orig.) [de

  14. Prediction of transition from common adolescent bipolar experiences to bipolar disorder: 10-year study. (United States)

    Tijssen, Marijn J A; van Os, Jim; Wittchen, Hans-Ulrich; Lieb, Roselind; Beesdo, Katja; Mengelers, Ron; Wichers, Marieke


    Although (hypo)manic symptoms are common in adolescence, transition to adult bipolar disorder is infrequent. To examine whether the risk of transition to bipolar disorder is conditional on the extent of persistence of subthreshold affective phenotypes. In a 10-year prospective community cohort study of 3021 adolescents and young adults, the association between persistence of affective symptoms over 3 years and the 10-year clinical outcomes of incident DSM-IV (hypo)manic episodes and incident use of mental healthcare was assessed. Transition to clinical outcome was associated with persistence of symptoms in a dose-dependent manner. Around 30-40% of clinical outcomes could be traced to prior persistence of affective symptoms. In a substantial proportion of individuals, onset of clinical bipolar disorder may be seen as the poor outcome of a developmentally common and usually transitory non-clinical bipolar phenotype.



    Babić, Dragan; Maslov, Boris; Nikolić, Katica; Martinac, Marko; Uzun, Suzana; Kozumplik, Oliver


    Objective: There is evidence that people with mental disorders are more likely to suffer from metabolic syndrome. In the last decades there has been an increase in interest for researching metabolic syndrome in psychiatric patients and plenty of evidence about their association. However, investigations on the prevalence of metabolic syndrome in patients with bipolar disorder are still surprisingly rare. The aim of this paper is to analyze comorbidity of bipolar disorder and metabolic syndrome...

  16. Depolarization of sperm membrane potential is a common feature of men with subfertility and is associated with low fertilization rate at IVF. (United States)

    Brown, Sean G; Publicover, Stephen J; Mansell, Steven A; Lishko, Polina V; Williams, Hannah L; Ramalingam, Mythili; Wilson, Stuart M; Barratt, Christopher L R; Sutton, Keith A; Da Silva, Sarah Martins


    Are significant abnormalities in outward (K(+)) conductance and resting membrane potential (Vm) present in the spermatozoa of patients undertaking IVF and ICSI and if so, what is their functional effect on fertilization success? Negligible outward conductance (≈5% of patients) or an enhanced inward conductance (≈4% of patients), both of which caused depolarization of Vm, were associated with a low rate of fertilization following IVF. Sperm-specific potassium channel knockout mice are infertile with defects in sperm function, suggesting that these channels are essential for fertility. These observations suggest that malfunction of K(+) channels in human spermatozoa might contribute significantly to the occurrence of subfertility in men. However, remarkably little is known of the nature of K(+) channels in human spermatozoa or the incidence and functional consequences of K(+) channel defects. Spermatozoa were obtained from healthy volunteer research donors and subfertile IVF and ICSI patients attending a hospital assisted reproductive techniques clinic between May 2013 and December 2015. In total, 40 IVF patients, 41 ICSI patients and 26 normozoospermic donors took part in the study. Samples were examined using electrophysiology (whole-cell patch clamping). Where abnormal electrophysiological characteristics were identified, spermatozoa were further examined for Ca(2+) influx induced by progesterone and penetration into viscous media if sufficient sample was available. Full exome sequencing was performed to specifically evaluate potassium calcium-activated channel subfamily M α 1 (KCNMA1), potassium calcium-activated channel subfamily U member 1 (KCNU1) and leucine-rich repeat containing 52 (LRRC52) genes and others associated with K(+) signalling. In IVF patients, comparison with fertilization rates was done to assess the functional significance of the electrophysiological abnormalities. Patch clamp electrophysiology was used to assess outward (K

  17. Implementation of depolarization due to beam-beam effects in the beam-beam interaction simulation tool GUINEA-PIG++ (United States)

    Rimbault, C.; Le Meur, G.; Blampuy, F.; Bambade, P.; Schulte, D.


    Depolarization is a new feature in the beam-beam simulation tool GUINEA-PIG++ (GP++). The results of this simulation are studied and compared with another beam-beam simulation tool, CAIN, considering different beam parameters for the International Linear Collider (ILC) with a centre-of-mass energy of 500 GeV.

  18. Spreading depolarization-modulating drugs and delayed cerebral ischemia after subarachnoid hemorrhage : A hypothesis-generating retrospective clinical study

    NARCIS (Netherlands)

    Hamming, Arend M.; Mulder, Inge A.; Gathier, Celine S.; van den Bergh, Walter M.; Dankbaar, Jan Willem; Hoff, Reinier G.; Vandertop, W. Peter; Verbaan, Dagmar; Ferrari, Michel D.; Rinkel, Gabriel J. E.; Algra, Ale; Wermer, Marieke J. H.


    Background: Delayed cerebral ischemia (DCI) occurs in approximately one-third of patients with aneurysmal subarachnoid hemorrhage (aSAH). A proposed underlying mechanism for DCI is spreading depolarization (SD). Our aim was to, retrospectively, investigate the influence of the use of SD-modulating

  19. Bipolar Disorder in Children and Teens (United States)

    ... separation anxiety. Sometimes behavior problems go along with mood episodes. Young people may take a lot of risks, such as driving too fast or spending too much money. Some young people with bipolar disorder think about suicide. Watch for any signs of suicidal thinking. Take ...

  20. Social dysfunction in bipolar disorder: pilot study. (United States)

    de Almeida Rocca, Cristiana Castanho; de Macedo-Soares, Marcia Britto; Gorenstein, Clarice; Tamada, Renata Sayuri; Issler, Cilly Kluger; Dias, Rodrigo Silva; Schwartzmann, Angela Maria; Lafer, Beny


    The purpose of the present study was to assess the social skills of euthymic patients with bipolar disorder. A group of 25 outpatients with bipolar disorder type I were evaluated in comparison with a group of 31 healthy volunteers who were matched in terms of level of education, age, sex and intelligence. Both groups were assessed using a self-report questionnaire, the Brazilian Inventario de Habilidades Sociais (IHS, Social Skills Inventory). Two Wechsler Adult Intelligence Scale subtests (Picture Arrangement and Comprehension) were also used in order to assess subject ability to analyse social situations and to make judgements, respectively. Patients with bipolar disorder had lower IHS scores for the domains that assessed conversational skills/social self-confidence and social openness to new people/situations. Patients with anxiety disorders had high scores for the domain that assessed self-confidence in the expression of positive emotions. No differences were found between patients and controls in performance on the Wechsler Adult Intelligence Scale Picture Arrangement and Comprehension subtests. Euthymic patients with bipolar disorder present inhibited and overattentive behaviour in relation to other people and their environment. This behaviour might have a negative impact on their level of social functioning and quality of life.