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Search Results: 1 - 10 of 325496 matches for " S. Appel "
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The Effects of Zinc and Other Divalent Cations on M-Current in Ventral Tegmental Area Dopamine Neurons  [PDF]
Susumu Koyama, Munechika Enjoji, Mark S. Brodie, Sarah B. Appel
Journal of Biomedical Science and Engineering (JBiSE) , 2014, DOI: 10.4236/jbise.2014.714105
Abstract: Ventral tegmental area dopamine (DA VTA) neurons are important for the reinforcing effects of drugs of abuse such as ethanol and nicotine. We have previously shown that M-current (IM) regulates the excitability of DA VTA neurons. Zinc (Zn2+) contributes to the regulation of neuronal excitation as a neuromodulator. In the present study, we investigated zinc effect on the properties of IM and the spontaneous firing frequency of DA VTA neurons. The standard deactivation protocol was used to measure IM during voltage-clamp recording with a hyperpolarizing voltage step to ﹣40 mV from a holding potential (VH) of ﹣25 mV. Zn2+ (100 μM) inhibited IM amplitude and IM recovered completely from the inhibition after the washout of Zn2+. Zn2+ inhibited IM in a concentration-dependent manner (IC50: 5.8 μM). When hyperpolarizing voltage steps were given to ﹣65 mV (in 10 mV increments) from a VH of ﹣25 mV, Zn2+ (100 μM) reduced IM amplitude at each voltage and zinc inhibition of IM was not voltage-dependent. Zn2+ increased the spontaneous firing frequency of DA VTA neurons in a concentration-dependent manner, suggesting that Zn2+ causes excitation of DA VTA neurons through an action on IM. IM of DA VTA neurons was inhibited by 100 μM divalent cations in increasing order of potency: Ba2+ (16%) < Co2+ (25%) < Ni2+ (40%) < Cd2+ (59%) < Zn2+ (67%). These results suggest that Zn2+ may exert physiologically significant regulation of neuronal excitability in DA VTA neurons.
A Persistent Na+ Current and Its Contribution to Burst-Like Firing in Ventral Tegmental Area Dopamine Neurons  [PDF]
Susumu Koyama, Munechika Enjoji, Mark S. Brodie, Sarah B. Appel
Journal of Biomedical Science and Engineering (JBiSE) , 2015, DOI: 10.4236/jbise.2015.87040
Abstract: The ventral tegmental area dopamine (DA VTA) neurons have the spontaneous tonic activity and an alteration of firing pattern from tonic to burst accelerates dopamine transmission more effectively in the mesoaccumbal dopaminergic system, leading to the reinforcing process of drugs of abuse such as alcohol and nicotine. In the present study, we examined whether a persistent Na+ current would contribute to burst firing in DA VTA neuronsusing nystatin-perforated recording. Tetrodotoxin (TTX) (1 μM) or riluzole (10 μM) hyperpolarized the membrane potential and stopped spontaneous firing of DA VTA neurons. In voltage-clamp analysis, a TTX and riluzole-sensitive and persistent Na+ current was activated at ?60 mV and reached maximal amplitude at ?40 mV. This persistent Na+ current was potentiated by a negative shift of the voltage of activation by eliminating Ca2+ from the extracellular solution. The Ca2+-free extracellular solution depolarized the membrane potential and increased the firing frequency of DA VTA neurons. When a continuous hyperpolarizing current was injected, the firing pattern of the DA VTA neurons transformed into burst-like firing; with average spike number of 4.9, average inter-spike interval of 221 ms, and an average plateau potential, on which the train of spikes generated, was 11 mV. The burst-like firing of DA VTA neurons was abolished by 10 μM riluzole. The concurrent blockade of both T-type Ca2+ current and small conductance Ca2+-activated K+(SK) currents by 100 μM nickel did not induce burst-like firing with or without continuous hyperpolarizing current injection in DA VTA neurons. In conclusion, increases in a persistent Na+ current that mediates a depolarizing driving force by removing extracellular Ca2+ contributes to burst-like firing in DA VTA neurons.
ROLE OF MICRO-FINANCIAL INSTITUTIONS AND WOMAN WORK PARTICIPATION IN RURALAREA: A CASE STUDY DOMKAL BLOCK, MURSIDABAD, W.B
S.M. APPEL MEHAMMUD,ANURADHA SENGUPTA
Indian Streams Research Journal , 2013,
Abstract: Since 1900 or earlier urbanization encroaching on rural land along with agromechanization has reduced the number of workers needed to work in land when alternative employment is easier in cities than rural sectors, lacking educational specialization. The rural areas are sub-divided by their proximity to urbanized area into fringes, distant or remote. Our study area, DUMKALBLOCK (lat.24.16'N long.88.27'E) situated in the south-eastern part of MURSHIDABAD, WB, is a remote area consisting of 311679 population within which 88.58% is Muslim, 40% belonging to BPL and only 56% is literate where women participation is only 43.5%.
The Multipath Approach to Personality: Towards a Unified Model of Self  [PDF]
Jonathan Appel, Dohee Kim-Appel
Psychology (PSYCH) , 2010, DOI: 10.4236/psych.2010.14036
Abstract: Human beings exist in multiple substrates or dimensions. But we still need more comprehensive and integrative theories of self-identity and personality. Most personality and developmental theories fail to adequately address the interaction among the psychological, interpersonal, environmental, and biological aspects of self and personality development. This paper presents a larger framework in which to examine prior models of personality as well as future integrative models. A Multipath Approach to Personality (MAP) is proposed and consists of the following dimensions or levels of analysis of self: 1) the Neuropersonal; 2) the Intrapersonal; 3) the Interpersonal; 4) the Exopersonal; 5) the Ecopersonal; and 6) the Transpersonal. The MAP approach to personality also suggests a multi-modal practice in assessment and research.
Heater self-calibration technique for shape prediction of fiber tapers
Heidi L. S?rensen,Eugene S. Polzik,Jürgen Appel
Physics , 2013, DOI: 10.1109/JLT.2014.2314319
Abstract: In the production of tapered optical fibers, it is important to control the fiber shape according to application-dependent requirements and to ensure adiabatic tapers. Especially in the transition regions, the fiber shape depends on the heater properties. The axial viscosity profile of the fiber within the heater can, however, be hard to access and is therefore often approximated by assuming a uniform temperature distribution. We present a method for easy experimental calibration of the viscosity profile within the heater. This allows the determination of the resultant fiber shape for arbitrary pulling procedures, using only an additional camera and the fiber drawing setup itself. We find very good agreement between the modeled and measured fiber shape.
Delta-Notch signaling and lateral inhibition in zebrafish spinal cord development: Correction
Bruce Appel, Lee Anne Givan, Judith S Eisen
BMC Developmental Biology , 2002, DOI: 10.1186/1471-213x-2-3
Abstract:
Delta-Notch signaling and lateral inhibition in zebrafish spinal cord development
Bruce Appel, Lee Anne Givan, Judith S Eisen
BMC Developmental Biology , 2001, DOI: 10.1186/1471-213x-1-13
Abstract: Zebrafish embryos express multiple delta and notch genes throughout the developing nervous system. All or most proliferative precursors appeared to express notch genes whereas subsets of precursors and post-mitotic neurons expressed delta genes. When we ablated identified primary motor neurons soon after they were born, they were replaced, indicating that specified neurons laterally inhibit neighboring precursors. Mutation of a delta gene caused precursor cells of the trunk neural tube to cease dividing prematurely and develop as neurons. Additionally, mutant embryos had excess early specified neurons, with fates appropriate for their normal positions within the neural tube, and a concomitant deficit of late specified cells.Our results are consistent with the idea that zebrafish Delta proteins, expressed by newly specified neurons, promote Notch activity in neighboring precursors. This signaling is required to maintain a proliferative precursor population and generate late-born neurons and glia. Thus, Delta-Notch signaling may diversify vertebrate neural cell fates by coordinating cell cycle control and cell specification.Specification of cells at different times and places is critical for generation of cellular diversity in the vertebrate nervous system. Distinct types of neurons and glia develop at characteristic times and places [1] and molecular signals that promote formation of different cell types are regulated spatially and temporally [2]. Thus, neural pattern formation requires coordination of signals that provide spatial and temporal information.Lateral inhibition, or lateral specification, is one process by which fine patterns of distinct cell types are generated [3, 4]. Among cells that have the potential to adopt the same fate, lateral inhibition specifies some cells for a primary or preferred fate and others for a secondary or alternative fate. Cell ablation experiments are used to identify lateral inhibition: when cells that would normally adopt a prim
Dendritic cell populations in patients with self-reported food hypersensitivity
Lied GA, Vogelsang P, Berstad A, Appel S
International Journal of General Medicine , 2011, DOI: http://dx.doi.org/10.2147/IJGM.S17655
Abstract: dritic cell populations in patients with self-reported food hypersensitivity Original Research (2936) Total Article Views Authors: Lied GA, Vogelsang P, Berstad A, Appel S Published Date May 2011 Volume 2011:4 Pages 389 - 396 DOI: http://dx.doi.org/10.2147/IJGM.S17655 Gülen A Lied1,3,4,*, Petra Vogelsang2,*, Arnold Berstad1,4, Silke Appel2 1Institute of Medicine, 2Broegelmann Research Laboratory, The Gade Institute, University of Bergen, Norway; 3Division of Gastroenterology, Department of Medicine; 4Section of Clinical Allergology, Department of Occupational Medicine, Haukeland University Hospital, Bergen, Norway *These authors contributed equally to this work Abstract: Self-reported hypersensitivity to food is a common condition and many of these patients have indications of intestinal immune activation. Dendritic cells (DCs) are recognized as the most potent antigen-presenting cells involved in both initiating immune responses and maintaining tolerance. The aims of this study were to evaluate the DC populations with their phenotype and T cell stimulatory capacity in patients with food hypersensitivity and to study its relationship with atopic disease. Blood samples from 10 patients with self-reported food hypersensitivity, divided into atopic and nonatopic subgroups, and 10 gender- and age-matched healthy controls were analyzed by flow cytometry using the Miltenyi Blood Dendritic cells kit. Monocyte-derived DCs (moDCs) were evaluated concerning their phenotype and T cell stimulatory capacity. DC populations and cell surface markers were not significantly different between patients and healthy controls, but moDCs from atopic patients expressed significantly more CD38 compared to moDCs from nonatopic patients. Moreover, lipopolysaccharide stimulated moDCs from atopic patients produced significantly more interleukin-10 compared to nonatopic patients. CD38 expression was correlated to total serum immunoglobulin E levels. These findings support the notion of immune activation in some patients with self-reported food hypersensitivity. They need to be confirmed in a larger cohort.
Dendritic cell populations in patients with self-reported food hypersensitivity
Lied GA,Vogelsang P,Berstad A,Appel S
International Journal of General Medicine , 2011,
Abstract: Gülen A Lied1,3,4,*, Petra Vogelsang2,*, Arnold Berstad1,4, Silke Appel2 1Institute of Medicine, 2Broegelmann Research Laboratory, The Gade Institute, University of Bergen, Norway; 3Division of Gastroenterology, Department of Medicine; 4Section of Clinical Allergology, Department of Occupational Medicine, Haukeland University Hospital, Bergen, Norway *These authors contributed equally to this workAbstract: Self-reported hypersensitivity to food is a common condition and many of these patients have indications of intestinal immune activation. Dendritic cells (DCs) are recognized as the most potent antigen-presenting cells involved in both initiating immune responses and maintaining tolerance. The aims of this study were to evaluate the DC populations with their phenotype and T cell stimulatory capacity in patients with food hypersensitivity and to study its relationship with atopic disease. Blood samples from 10 patients with self-reported food hypersensitivity, divided into atopic and nonatopic subgroups, and 10 gender- and age-matched healthy controls were analyzed by flow cytometry using the Miltenyi Blood Dendritic cells kit. Monocyte-derived DCs (moDCs) were evaluated concerning their phenotype and T cell stimulatory capacity. DC populations and cell surface markers were not significantly different between patients and healthy controls, but moDCs from atopic patients expressed significantly more CD38 compared to moDCs from nonatopic patients. Moreover, lipopolysaccharide stimulated moDCs from atopic patients produced significantly more interleukin-10 compared to nonatopic patients. CD38 expression was correlated to total serum immunoglobulin E levels. These findings support the notion of immune activation in some patients with self-reported food hypersensitivity. They need to be confirmed in a larger cohort.Keywords: food hypersensitivity, atopy, dendritic cells, CD38
Spin squeezing of atomic ensembles by multi-colour quantum non-demolition measurements
M. Saffman,D. Oblak,J. Appel,E. S. Polzik
Physics , 2008, DOI: 10.1103/PhysRevA.79.023831
Abstract: We analyze the creation of spin squeezed atomic ensembles by simultaneous dispersive interactions with several optical frequencies. A judicious choice of optical parameters enables optimization of an interferometric detection scheme that suppresses inhomogeneous light shifts and keeps the interferometer operating in a balanced mode that minimizes technical noise. We show that when the atoms interact with two-frequency light tuned to cycling transitions the degree of spin squeezing $\xi^2$ scales as $\xi^2\sim 1/d$ where $d$ is the resonant optical depth of the ensemble. In real alkali atoms there are loss channels and the scaling may be closer to $\xi^2\sim 1/\sqrt d.$ Nevertheless the use of two-frequencies provides a significant improvement in the degree of squeezing attainable as we show by quantitative analysis of non-resonant probing on the Cs D1 line. Two alternative configurations are analyzed: a Mach-Zehnder interferometer that uses spatial interference, and an interaction with multi-frequency amplitude modulated light that does not require a spatial interferometer.
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