Dewetting-mediated pattern formation inside the coffee ring

NASA Astrophysics Data System (ADS)

Li, Weibin; Lan, Ding; Wang, Yuren

2017-04-01

The rearrangement of particles in the final stage of droplet evaporation has been investigated by utilizing differential interference contrast microscopy and the formation mechanism of a network pattern inside a coffee ring has been revealed. A tailored substrate with a circular hydrophilic domain is prepared to obtain thin liquid film containing monolayer particles. Real-time bottom-view images show that the evolution of a dry patch could be divided into three stages: rupture initiation, dry patch expansion, and drying of the residual liquid. A growing number of dry patches will repeat these stages to form the network patterns inside the ringlike stain. It can be shown that the suction effect promotes the rupture of the liquid film and the formation of the dry patch. The particle-assembling process is totally controlled by the liquid film dewetting and dominated by the surface tension of the liquid film, which eventually determine the ultimate deposition patterns.

The hSK4 (KCNN4) isoform is the Ca2+-activated K+ channel (Gardos channel) in human red blood cells.

PubMed

Hoffman, Joseph F; Joiner, William; Nehrke, Keith; Potapova, Olga; Foye, Kristen; Wickrema, Amittha

2003-06-10

The question is, does the isoform hSK4, also designated KCNN4, represent the small conductance, Ca2+-activated K+ channel (Gardos channel) in human red blood cells? We have analyzed human reticulocyte RNA by RT-PCR, and, of the four isoforms of SK channels known, only SK4 was found. Northern blot analysis of purified and synchronously growing human erythroid progenitor cells, differentiating from erythroblasts to reticulocytes, again showed only the presence of SK4. Western blot analysis, with an anti-SK4 antibody, showed that human erythroid progenitor cells and, importantly, mature human red blood cell ghost membranes, both expressed the SK4 protein. The Gardos channel is known to turn on, given inside Ca2+, in the presence but not the absence of external Ko+ and remains refractory to Ko+ added after exposure to inside Ca2+. Heterologously expressed SK4, but not SK3, also shows this behavior. In inside-out patches of red cell membranes, the open probability (Po) of the Gardos channel is markedly reduced when the temperature is raised from 27 to 37 degrees C. Net K+ efflux of intact red cells is also reduced by increasing temperature, as are the Po values of inside-out patches of Chinese hamster ovary cells expressing SK4 (but not SK3). Thus the envelope of evidence indicates that SK4 is the gene that codes for the Gardos channel in human red blood cells. This channel is important pathophysiologically, because it represents the major pathway for cell shrinkage via KCl and water loss that occurs in sickle cell disease.

Flip the tip: an automated, high quality, cost-effective patch clamp screen.

PubMed

Lepple-Wienhues, Albrecht; Ferlinz, Klaus; Seeger, Achim; Schäfer, Arvid

2003-01-01

The race for creating an automated patch clamp has begun. Here, we present a novel technology to produce true gigaseals and whole cell preparations at a high rate. Suspended cells are flushed toward the tip of glass micropipettes. Seal, whole-cell break-in, and pipette/liquid handling are fully automated. Extremely stable seals and access resistance guarantee high recording quality. Data obtained from different cell types sealed inside pipettes show long-term stability, voltage clamp and seal quality, as well as block by compounds in the pM range. A flexible array of independent electrode positions minimizes consumables consumption at maximal throughput. Pulled micropipettes guarantee a proven gigaseal substrate with ultra clean and smooth surface at low cost.

Photo-patch and patch tests in patients with dermatitis over the photo-exposed areas: A study of 101 cases from a tertiary care centre in India.

PubMed

Sharma, Vinod Kumar; Bhari, Neetu; Wadhwani, Ashok Roopchand; Bhatia, Riti

2018-02-01

Many patients with dermatitis over photo-exposed body areas are positive to many contact allergens and have a pre-existing allergic contact dermatitis. This study included patients who presented to a tertiary centre in India with dermatitis on photo-exposed body areas suspected of chronic actinic dermatitis. Their detailed histories were recorded and cutaneous and systemic examinations were performed. Patch testing was done in all the patients and photo-patch testing was carried out in 86 patients. Altogether 101 patients were included (69 males, 32 females). The most common presentation was lichenified hyperpigmented plaques on the photo-exposed sites. Photosensitivity was recorded in 64 (63%) patients and summer exacerbation in 52 (52%). Exposure to the Parthenium hysterophorus weed was recorded in 70 (69%) patients, 27 (26.7%) had a history of hair dye application and 20 (20%) had a history of atopy. Photo-patch test was positive in 11 (12.8%) patients and patch testing was positive in 71 (70%). Parthenium hysterophorus was the most common allergen implicated and was positive in three (4%) photo-patch and 52 (52%) patch tests. Other positive photo-patch test allergens were perfume mix, balsam of Peru, thiuram mix, Compositae mix and promethazine hydrochloride. Other common patch test allergens were parthenolide, colophony, fragrance mix and p-phenylenediamine (PPD) base. In the Indian population parthenium and perfume mix are the most common photoallergens in patients with dermatitis over photo-exposed areas, while parthenium, colophony, fragrance mix and PPD are the common positive allergens. © 2016 The Australasian College of Dermatologists.

Diffusion-convection effects on drug distribution at the cell membrane level in a patch-clamp setup.

PubMed

Baran, Irina; Iftime, Adrian; Popescu, Anca

2010-01-01

We present a model-based method for estimating the effective concentration of the active drug applied by a pressure pulse to an individual cell in a patch-clamp setup, which could be of practical use in the analysis of ligand-induced whole-cell currents recorded in patch-clamp experiments. Our modelling results outline several important factors which may be involved in the high variability of the electric response of the cells, and indicate that with a pressure pulse duration of 1s and diameter of the perfusion tip of 600 μm, elevated amounts of drug can accumulate locally between the pipette tip and the cell. Hence, the effective agonist concentration at the cell membrane level can be consistently higher than the initial concentration inside the perfusion tubes. We performed finite-difference and finite-element simulations to investigate the diffusion/convection effects on the agonist distribution on the cell membrane. Our model can explain the delay between the commencement of acetylcholine application and the onset of the whole-cell current that we recorded on human rhabdomyosarcoma TE671 cells, and reproduce quantitatively the decrease of signal latency with the concentration of agonist in the pipette. Results also show that not only the geometry of the bath chamber and pipette tip, but also the transport parameters of the diffusive and convective phenomena in the bath solution are determinant for the amplitude and kinetics of the recorded currents and have to be accounted for when analyzing patch-clamp data. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Neurophysiological Organization of the Middle Face Patch in Macaque Inferior Temporal Cortex

PubMed Central

Aparicio, Paul L.; Issa, Elias B.

2016-01-01

While early cortical visual areas contain fine scale spatial organization of neuronal properties, such as orientation preference, the spatial organization of higher-level visual areas is less well understood. The fMRI demonstration of face-preferring regions in human ventral cortex and monkey inferior temporal cortex (“face patches”) raises the question of how neural selectivity for faces is organized. Here, we targeted hundreds of spatially registered neural recordings to the largest fMRI-identified face-preferring region in monkeys, the middle face patch (MFP), and show that the MFP contains a graded enrichment of face-preferring neurons. At its center, as much as 93% of the sites we sampled responded twice as strongly to faces than to nonface objects. We estimate the maximum neurophysiological size of the MFP to be ∼6 mm in diameter, consistent with its previously reported size under fMRI. Importantly, face selectivity in the MFP varied strongly even between neighboring sites. Additionally, extremely face-selective sites were ∼40 times more likely to be present inside the MFP than outside. These results provide the first direct quantification of the size and neural composition of the MFP by showing that the cortical tissue localized to the fMRI defined region consists of a very high fraction of face-preferring sites near its center, and a monotonic decrease in that fraction along any radial spatial axis. SIGNIFICANCE STATEMENT The underlying organization of neurons that give rise to the large spatial regions of activity observed with fMRI is not well understood. Neurophysiological studies that have targeted the fMRI identified face patches in monkeys have provided evidence for both large-scale clustering and a heterogeneous spatial organization. Here we used a novel x-ray imaging system to spatially map the responses of hundreds of sites in and around the middle face patch. We observed that face-selective signal localized to the middle face patch was characterized by a gradual spatial enrichment. Furthermore, strongly face-selective sites were ∼40 times more likely to be found inside the patch than outside of the patch. PMID:27810930

Thick-shelled, grazer-protected diatoms decouple ocean carbon and silicon cycles in the iron-limited Antarctic Circumpolar Current

PubMed Central

Assmy, Philipp; Smetacek, Victor; Montresor, Marina; Klaas, Christine; Henjes, Joachim; Strass, Volker H.; Arrieta, Jesús M.; Bathmann, Ulrich; Berg, Gry M.; Breitbarth, Eike; Cisewski, Boris; Friedrichs, Lars; Fuchs, Nike; Herndl, Gerhard J.; Jansen, Sandra; Krägefsky, Sören; Latasa, Mikel; Peeken, Ilka; Röttgers, Rüdiger; Scharek, Renate; Schüller, Susanne E.; Steigenberger, Sebastian; Webb, Adrian; Wolf-Gladrow, Dieter

2013-01-01

Diatoms of the iron-replete continental margins and North Atlantic are key exporters of organic carbon. In contrast, diatoms of the iron-limited Antarctic Circumpolar Current sequester silicon, but comparatively little carbon, in the underlying deep ocean and sediments. Because the Southern Ocean is the major hub of oceanic nutrient distribution, selective silicon sequestration there limits diatom blooms elsewhere and consequently the biotic carbon sequestration potential of the entire ocean. We investigated this paradox in an in situ iron fertilization experiment by comparing accumulation and sinking of diatom populations inside and outside the iron-fertilized patch over 5 wk. A bloom comprising various thin- and thick-shelled diatom species developed inside the patch despite the presence of large grazer populations. After the third week, most of the thinner-shelled diatom species underwent mass mortality, formed large, mucous aggregates, and sank out en masse (carbon sinkers). In contrast, thicker-shelled species, in particular Fragilariopsis kerguelensis, persisted in the surface layers, sank mainly empty shells continuously, and reduced silicate concentrations to similar levels both inside and outside the patch (silica sinkers). These patterns imply that thick-shelled, hence grazer-protected, diatom species evolved in response to heavy copepod grazing pressure in the presence of an abundant silicate supply. The ecology of these silica-sinking species decouples silicon and carbon cycles in the iron-limited Southern Ocean, whereas carbon-sinking species, when stimulated by iron fertilization, export more carbon per silicon. Our results suggest that large-scale iron fertilization of the silicate-rich Southern Ocean will not change silicon sequestration but will add carbon to the sinking silica flux. PMID:24248337

Melatonin mediates vasodilation through both direct and indirect activation of BKCa channels.

PubMed

Zhao, T; Zhang, H; Jin, C; Qiu, F; Wu, Y; Shi, L

2017-10-01

Melatonin, synthesized primarily by the pineal gland, is a neuroendocrine hormone with high membrane permeability. The vascular effects of melatonin, including vasoconstriction and vasodilation, have been demonstrated in numerous studies. However, the mechanisms underlying these effects are not fully understood. Large-conductance Ca 2+ -activated K + (BK Ca ) channels are expressed broadly on smooth muscle cells and play an important role in vascular tone regulation. This study explored the mechanisms of myocyte BK Ca channels and endothelial factors underlying the action of melatonin on the mesenteric arteries (MAs). Vascular contractility and patch-clamp studies were performed on myocytes of MAs from Wistar rats. Melatonin induced significant vasodilation on MAs. In the presence of N ω -nitro-l-arginine methyl ester (l-NAME), a potent endothelial oxide synthase (eNOS) inhibitor, melatonin elicited concentration-dependent relaxation, with lowered pIC 50 The effect of melatonin was significantly attenuated in the presence of BK Ca channel blocker iberiotoxin or MT1/MT2 receptor antagonist luzindole in both (+) l-NAME and (-) l-NAME groups. In the (+) l-NAME group, iberiotoxin caused a parallel rightward shift of the melatonin concentration-relaxation curve, with pIC 50 lower than that of luzindole. Both inside-out and cell-attached patch-clamp recordings showed that melatonin significantly increased the open probability, mean open time and voltage sensitivity of BK Ca channels. In a cell-attached patch-clamp configuration, the melatonin-induced enhancement of BK Ca channel activity was significantly suppressed by luzindole. These findings indicate that in addition to the activation of eNOS, melatonin-induced vasorelaxation of MAs is partially attributable to its direct (passing through the cell membrane) and indirect (via MT1/MT2 receptors) activation of the BK Ca channels on mesenteric arterial myocytes. © 2017 Society for Endocrinology.

Glutamate receptor-channel gating. Maximum likelihood analysis of gigaohm seal recordings from locust muscle.

PubMed Central

Bates, S E; Sansom, M S; Ball, F G; Ramsey, R L; Usherwood, P N

1990-01-01

Gigaohm recordings have been made from glutamate receptor channels in excised, outside-out patches of collagenase-treated locust muscle membrane. The channels in the excised patches exhibit the kinetic state switching first seen in megaohm recordings from intact muscle fibers. Analysis of channel dwell time distributions reveals that the gating mechanism contains at least four open states and at least four closed states. Dwell time autocorrelation function analysis shows that there are at least three gateways linking the open states of the channel with the closed states. A maximum likelihood procedure has been used to fit six different gating models to the single channel data. Of these models, a cooperative model yields the best fit, and accurately predicts most features of the observed channel gating kinetics. PMID:1696510

Obtaining spheroplasts of armored dinoflagellates and first single-channel recordings of their ion channels using patch-clamping.

PubMed

Pozdnyakov, Ilya; Matantseva, Olga; Negulyaev, Yuri; Skarlato, Sergei

2014-09-05

Ion channels are tightly involved in various aspects of cell physiology, including cell signaling, proliferation, motility, endo- and exo-cytosis. They may be involved in toxin production and release by marine dinoflagellates, as well as harmful algal bloom proliferation. So far, the patch-clamp technique, which is the most powerful method to study the activity of ion channels, has not been applied to dinoflagellate cells, due to their complex cellulose-containing cell coverings. In this paper, we describe a new approach to overcome this problem, based on the preparation of spheroplasts from armored bloom-forming dinoflagellate Prorocentrum minimum. We treated the cells of P. minimum with a cellulose synthesis inhibitor, 2,6-dichlorobenzonitrile (DCB), and found out that it could also induce ecdysis and arrest cell shape maintenance in these microalgae. Treatment with 100-250 µM DCB led to an acceptable 10% yield of P. minimum spheroplasts and was independent of the incubation time in the range of 1-5 days. We show that such spheroplasts are suitable for patch-clamping in the cell-attached mode and can form 1-10 GOhm patch contact with a glass micropipette, allowing recording of ion channel activity. The first single-channel recordings of dinoflagellate ion channels are presented.

Obtaining Spheroplasts of Armored Dinoflagellates and First Single-Channel Recordings of Their Ion Channels Using Patch-Clamping

PubMed Central

Pozdnyakov, Ilya; Matantseva, Olga; Negulyaev, Yuri; Skarlato, Sergei

2014-01-01

Ion channels are tightly involved in various aspects of cell physiology, including cell signaling, proliferation, motility, endo- and exo-cytosis. They may be involved in toxin production and release by marine dinoflagellates, as well as harmful algal bloom proliferation. So far, the patch-clamp technique, which is the most powerful method to study the activity of ion channels, has not been applied to dinoflagellate cells, due to their complex cellulose-containing cell coverings. In this paper, we describe a new approach to overcome this problem, based on the preparation of spheroplasts from armored bloom-forming dinoflagellate Prorocentrum minimum. We treated the cells of P. minimum with a cellulose synthesis inhibitor, 2,6-dichlorobenzonitrile (DCB), and found out that it could also induce ecdysis and arrest cell shape maintenance in these microalgae. Treatment with 100–250 µM DCB led to an acceptable 10% yield of P. minimum spheroplasts and was independent of the incubation time in the range of 1–5 days. We show that such spheroplasts are suitable for patch-clamping in the cell-attached mode and can form 1–10 GOhm patch contact with a glass micropipette, allowing recording of ion channel activity. The first single-channel recordings of dinoflagellate ion channels are presented. PMID:25199048

Seasonality and edge effect determine herbivory risk according to different plant association models.

PubMed

Miranda, M; Díaz, L; Sicilia, M; Cristóbal, I; Cassinello, J

2011-01-01

We report evidence of hierarchical resource selection by large herbivores and plant neighbouring effects in a Mediterranean ecosystem. Plant palatability was assessed according to herbivore foraging decisions. We hypothesize that under natural conditions large herbivores follow a hierarchical foraging pattern, starting at the landscape scale, and then selecting patches and individual plants. A between- and within-patch selection study was carried out in an area formed by scrubland and pasture patches, connected by habitat edges. With regard to between-patch selection, quality-dependent resource selection is reported: herbivores mainly consume pasture in spring and woody plants in winter. Within-patch selection was also observed in scrub habitats, influenced by season, relative patch palatability and edge effect. We defined a Proximity Index (PI) between palatable and unpalatable plants, which allowed verification of neighbouring effects. In spring, when the preferred food resource (i.e. herbs) is abundant, we observed that in habitat edges large herbivores basically select the relatively scarce palatable shrubs, whereas inside scrubland, unpalatable shrub consumption was related to increasing PI. In winter, a very different picture was observed; there was low consumption of palatable species surrounded by unpalatable species in habitat edges, where the latter were more abundant. These outcomes could be explained though different plant associations described in the literature. We conclude that optimal foraging theory provides a conceptual framework behind the observed interactions between plants and large herbivores in Mediterranean ecosystems. © 2010 German Botanical Society and The Royal Botanical Society of the Netherlands.

Patching the Exchange-Correlation Potential in Density Functional Theory.

PubMed

Huang, Chen

2016-05-10

A method for directly patching exchange-correlation (XC) potentials in materials is derived. The electron density of a system is partitioned into subsystem densities by dividing its Kohn-Sham (KS) potential among the subsystems. Inside each subsystem, its projected KS potential is required to become the total system's KS potential. This requirement, together with the nearsightedness principle of electronic matters, ensures that the electronic structures inside subsystems can be good approximations to the total system's electronic structure. The nearsightedness principle also ensures that subsystem densities could be well localized in their regions, making it possible to use high-level methods to invert the XC potentials for subsystem densities. Two XC patching methods are developed. In the local XC patching method, the total system's XC potential is improved in the cluster region. We show that the coupling between a cluster and its environment is important for achieving a fast convergence of the electronic structure in the cluster region. In the global XC patching method, we discuss how to patch the subsystem XC potentials to construct the XC potential in the total system, aiming to scale up high-level quantum mechanics simulations of materials. Proof-of-principle examples are given.

Modulation of inward rectifier potassium channel by toosendanin, a presynaptic blocker.

PubMed

Wang, Z F; Shi, Y L

2001-07-01

The effect of toosendanin, a presynaptic blocker, on the inward rectifier potassium channel (K(Kir)) of hippocampal CA1 pyramidal neurons of rats was studied by the single-channel patch-clamp technique. The results showed that toosendanin had an inhibitory effect on K(Kir) in an excised inside-out patch of the neuron under a symmetrical 150 mM K(+) condition. By decreasing the slower open time constant and increasing the slower close time constant, toosendanin (1x10(-6)-1x10(-4) g/ml) significantly reduced the open probability of the channel in a concentration-dependent manner. Meanwhile, a dose-dependent reduction in unitary conductance of the channel was also detected after toosendanin application. These data offer an explanation for toosendanin-induced facilitation of neurotransmitter release and antibotulismic effect of the drug.

Rigging dark haloes: why is hierarchical galaxy formation consistent with the inside-out build-up of thin discs?

NASA Astrophysics Data System (ADS)

Pichon, C.; Pogosyan, D.; Kimm, T.; Slyz, A.; Devriendt, J.; Dubois, Y.

2011-12-01

State-of-the-art hydrodynamical simulations show that gas inflow through the virial sphere of dark matter haloes is focused (i.e. has a preferred inflow direction), consistent (i.e. its orientation is steady in time) and amplified (i.e. the amplitude of its advected specific angular momentum increases with time). We explain this to be a consequence of the dynamics of the cosmic web within the neighbourhood of the halo, which produces steady, angular momentum rich, filamentary inflow of cold gas. On large scales, the dynamics within neighbouring patches drives matter out of the surrounding voids, into walls and filaments before it finally gets accreted on to virialized dark matter haloes. As these walls/filaments constitute the boundaries of asymmetric voids, they acquire a net transverse motion, which explains the angular momentum rich nature of the later infall which comes from further away. We conjecture that this large-scale driven consistency explains why cold flows are so efficient at building up high-redshift thin discs inside out.

Ion channel recordings on an injection-molded polymer chip.

PubMed

Tanzi, Simone; Matteucci, Marco; Christiansen, Thomas Lehrmann; Friis, Søren; Christensen, Mette Thylstrup; Garnaes, Joergen; Wilson, Sandra; Kutchinsky, Jonatan; Taboryski, Rafael

2013-12-21

In this paper, we demonstrate recordings of the ion channel activity across the cell membrane in a biological cell by employing the so-called patch clamping technique on an injection-molded polymer microfluidic device. The findings will allow direct recordings of ion channel activity to be made using the cheapest materials and production platform to date and with the potential for very high throughput. The employment of cornered apertures for cell capture allowed the fabrication of devices without through holes and via a scheme comprising master origination by dry etching in a silicon substrate, electroplating in nickel and injection molding of the final part. The most critical device parameters were identified as the length of the patching capillary and the very low surface roughness on the inside of the capillary. The cross-sectional shape of the orifice was found to be less critical, as both rectangular and semicircular profiles seemed to have almost the same ability to form tight seals with cells with negligible leak currents. The devices were functionally tested using human embryonic kidney cells expressing voltage-gated sodium channels (Nav1.7) and benchmarked against a commercial state-of-the-art system for automated ion channel recordings. These experiments considered current-voltage (IV) relationships for activation and inactivation of the Nav1.7 channels and their sensitivity to a local anesthetic, lidocaine. Both IVs and lidocaine dose-response curves obtained from the injection-molded polymer device were in good agreement with data obtained from the commercial system.

Mutations in Nature Conferred a High Affinity Phosphatidylinositol 4,5-Bisphosphate-binding Site in Vertebrate Inwardly Rectifying Potassium Channels*

PubMed Central

Tang, Qiong-Yao; Larry, Trevor; Hendra, Kalen; Yamamoto, Erica; Bell, Jessica; Cui, Meng; Logothetis, Diomedes E.; Boland, Linda M.

2015-01-01

All vertebrate inwardly rectifying potassium (Kir) channels are activated by phosphatidylinositol 4,5-bisphosphate (PIP2) (Logothetis, D. E., Petrou, V. I., Zhang, M., Mahajan, R., Meng, X. Y., Adney, S. K., Cui, M., and Baki, L. (2015) Annu. Rev. Physiol. 77, 81–104; Fürst, O., Mondou, B., and D'Avanzo, N. (2014) Front. Physiol. 4, 404–404). Structural components of a PIP2-binding site are conserved in vertebrate Kir channels but not in distantly related animals such as sponges and sea anemones. To expand our understanding of the structure-function relationships of PIP2 regulation of Kir channels, we studied AqKir, which was cloned from the marine sponge Amphimedon queenslandica, an animal that represents the phylogenetically oldest metazoans. A requirement for PIP2 in the maintenance of AqKir activity was examined in intact oocytes by activation of a co-expressed voltage-sensing phosphatase, application of wortmannin (at micromolar concentrations), and activation of a co-expressed muscarinic acetylcholine receptor. All three mechanisms to reduce the availability of PIP2 resulted in inhibition of AqKir current. However, time-dependent rundown of AqKir currents in inside-out patches could not be re-activated by direct application to the inside membrane surface of water-soluble dioctanoyl PIP2, and the current was incompletely re-activated by the more hydrophobic arachidonyl stearyl PIP2. When we introduced mutations to AqKir to restore two positive charges within the vertebrate PIP2-binding site, both forms of PIP2 strongly re-activated the mutant sponge channels in inside-out patches. Molecular dynamics simulations validate the additional hydrogen bonding potential of the sponge channel mutants. Thus, nature's mutations conferred a high affinity activation of vertebrate Kir channels by PIP2, and this is a more recent evolutionary development than the structures that explain ion channel selectivity and inward rectification. PMID:25957411

Phorbol ester impairs electrical excitation of rat pancreatic beta-cells through PKC-independent activation of KATP channels.

PubMed

Suga, S; Wu, J; Ogawa, Y; Takeo, T; Kanno, T; Wakui, M

2001-01-01

Phorbol 12-myristate 13-acetate (PMA) is often used as an activating phorbol ester of protein kinase C (PKC) to investigate the roles of the kinase in cellular functions. Accumulating lines of evidence indicate that in addition to activating PKC, PMA also produces some regulatory effects in a PKC-independent manner. In this study, we investigated the non-PKC effects of PMA on electrical excitability of rat pancreatic beta-cells by using patch-clamp techniques. In current-clamp recording, PMA (80 nM) reversibly inhibited 15 mM glucose-induced action potential spikes superimposed on a slow membrane depolarization and this inhibition can not be prevented by pre-treatment of the cell with a specific PKC inhibitor, bisindolylmaleimide (BIM, 1 microM). In the presence of a subthreshold concentration (5.5 mM) of glucose, PMA hyperpolarized beta-cells in a concentration-dependent manner (0.8-240 nM), even in the presence of BIM. Based on cell-attached single channel recordings, PMA increased ATP-sensitive K+ channel (KATP) activity. Based on inside-out patch-clamp recordings, PMA had little effect on KATP activity if no ATP was in the bath, while PMA restored KATP activity that was suppressed by 10 microM ATP in the bath. In voltage-clamp recording, PMA enhanced tolbutamide-sensitive membrane currents elicited by repetitive ramp pulses from -90 to -50 mV in a concentration-dependent manner, and this potentiation could not be prevented by pre-treatment of cell with BIM. 4alpha-phorbol 12,13-didecanoate (4alpha-PDD), a non-PKC-activating phorbol ester, mimicked the effect of PMA on both current-clamp and voltage-clamp recording configurations. With either 5.5 or 16.6 mM glucose in the extracellular solution, PMA (80 nM) increased insulin secretion from rat islets. However, in islets pretreated with BIM (1 microM), PMA did not increase, but rather reduced insulin secretion. In rat pancreatic beta-cells, PMA modulates insulin secretion through a mixed mechanism: increases insulin secretion by activation of PKC, and meanwhile decrease insulin secretion by impairing beta-cell excitability in a PKC-independent manner. The enhancement of KATP activity by reducing sensitivity of KATP to ATP seems to underlie the PMA-induced impairment of beta-cells electrical excitation in response to glucose stimulation.

EBG Based Microstrip Patch Antenna for Brain Tumor Detection via Scattering Parameters in Microwave Imaging System.

PubMed

Inum, Reefat; Rana, Md Masud; Shushama, Kamrun Nahar; Quader, Md Anwarul

2018-01-01

A microwave brain imaging system model is envisaged to detect and visualize tumor inside the human brain. A compact and efficient microstrip patch antenna is used in the imaging technique to transmit equivalent signal and receive backscattering signal from the stratified human head model. Electromagnetic band gap (EBG) structure is incorporated on the antenna ground plane to enhance the performance. Rectangular and circular EBG structures are proposed to investigate the antenna performance. Incorporation of circular EBG on the antenna ground plane provides an improvement of 22.77% in return loss, 5.84% in impedance bandwidth, and 16.53% in antenna gain with respect to the patch antenna with rectangular EBG. The simulation results obtained from CST are compared to those obtained from HFSS to validate the design. Specific absorption rate (SAR) of the modeled head tissue for the proposed antenna is determined. Different SAR values are compared with the established standard SAR limit to provide a safety regulation of the imaging system. A monostatic radar-based confocal microwave imaging algorithm is applied to generate the image of tumor inside a six-layer human head phantom model. S -parameter signals obtained from circular EBG loaded patch antenna in different scanning modes are utilized in the imaging algorithm to effectively produce a high-resolution image which reliably indicates the presence of tumor inside human brain.

EBG Based Microstrip Patch Antenna for Brain Tumor Detection via Scattering Parameters in Microwave Imaging System

PubMed Central

Rana, Md. Masud; Shushama, Kamrun Nahar; Quader, Md. Anwarul

2018-01-01

A microwave brain imaging system model is envisaged to detect and visualize tumor inside the human brain. A compact and efficient microstrip patch antenna is used in the imaging technique to transmit equivalent signal and receive backscattering signal from the stratified human head model. Electromagnetic band gap (EBG) structure is incorporated on the antenna ground plane to enhance the performance. Rectangular and circular EBG structures are proposed to investigate the antenna performance. Incorporation of circular EBG on the antenna ground plane provides an improvement of 22.77% in return loss, 5.84% in impedance bandwidth, and 16.53% in antenna gain with respect to the patch antenna with rectangular EBG. The simulation results obtained from CST are compared to those obtained from HFSS to validate the design. Specific absorption rate (SAR) of the modeled head tissue for the proposed antenna is determined. Different SAR values are compared with the established standard SAR limit to provide a safety regulation of the imaging system. A monostatic radar-based confocal microwave imaging algorithm is applied to generate the image of tumor inside a six-layer human head phantom model. S-parameter signals obtained from circular EBG loaded patch antenna in different scanning modes are utilized in the imaging algorithm to effectively produce a high-resolution image which reliably indicates the presence of tumor inside human brain. PMID:29623087

Stimulation of the BKCa channel in cultured smooth muscle cells of human trachea by magnolol

PubMed Central

Wu, S; Chen, C; Li, H; Lo, Y; Chen, S; Chiang, H

2002-01-01

Background: Magnolol, a compound isolated from the cortex of Magnolia officinalis, has been found to possess anti-allergic and anti-asthmatic activity. Methods: The effect of magnolol on ionic currents was studied in cultured smooth muscle cells of human trachea with the aid of the patch clamp technique. Results: In whole cell current recordings magnolol reversibly increased the amplitude of K+ outward currents. The increase in outward current caused by magnolol was sensitive to inhibition by iberiotoxin (200 nM) or paxilline (1 µM) but not by glibenclamide (10 µM). In inside out patches, magnolol added to the bath did not modify single channel conductance but effectively enhanced the activity of large conductance Ca2+ activated K+ (BKCa) channels. Magnolol increased the probability of these channel openings in a concentration dependent manner with an EC50 value of 1.5 µM. The magnolol stimulated increase in the probability of channels opening was independent of internal Ca2+. The application of magnolol also shifted the activation curve of BKCa channels to less positive membrane potentials. The change in the kinetic behaviour of BKCa channels caused by magnolol in these cells is the result of an increase in dissociation and gating constants. Conclusions: These results provide evidence that, in addition to the presence of antioxidative activity, magnolol is potent in stimulating BKCa channel activity in tracheal smooth muscle cells. The direct stimulation of these BKCa channels by magnolol may contribute to the underlying mechanism by which it acts as an anti-asthmatic compound. PMID:11809993

Novel mechanism of hydrogen sulfide-induced guinea pig urinary bladder smooth muscle contraction: role of BK channels and cholinergic neurotransmission

PubMed Central

Fernandes, Vítor S.; Xin, Wenkuan

2015-01-01

Hydrogen sulfide (H2S) is a key signaling molecule regulating important physiological processes, including smooth muscle function. However, the mechanisms underlying H2S-induced detrusor smooth muscle (DSM) contractions are not well understood. This study investigates the cellular and tissue mechanisms by which H2S regulates DSM contractility, excitatory neurotransmission, and large-conductance voltage- and Ca2+-activated K+ (BK) channels in freshly isolated guinea pig DSM. We used a multidisciplinary experimental approach including isometric DSM tension recordings, colorimetric ACh measurement, Ca2+ imaging, and patch-clamp electrophysiology. In isolated DSM strips, the novel slow release H2S donor, P-(4-methoxyphenyl)-p-4-morpholinylphosphinodithioic acid morpholine salt (GYY4137), significantly increased the spontaneous phasic and nerve-evoked DSM contractions. The blockade of neuronal voltage-gated Na+ channels or muscarinic ACh receptors with tetrodotoxin or atropine, respectively, reduced the stimulatory effect of GYY4137 on DSM contractility. GYY4137 increased ACh release from bladder nerves, which was inhibited upon blockade of L-type voltage-gated Ca2+ channels with nifedipine. Furthermore, GYY4137 increased the amplitude of the Ca2+ transients and basal Ca2+ levels in isolated DSM strips. GYY4137 reduced the DSM relaxation induced by the BK channel opener, NS11021. In freshly isolated DSM cells, GYY4137 decreased the amplitude and frequency of transient BK currents recorded in a perforated whole cell configuration and reduced the single BK channel open probability measured in excised inside-out patches. GYY4137 inhibited spontaneous transient hyperpolarizations and depolarized the DSM cell membrane potential. Our results reveal the novel findings that H2S increases spontaneous phasic and nerve-evoked DSM contractions by activating ACh release from bladder nerves in combination with a direct inhibition of DSM BK channels. PMID:25948731

TRPM4 non-selective cation channels influence action potentials in rabbit Purkinje fibres.

PubMed

Hof, Thomas; Sallé, Laurent; Coulbault, Laurent; Richer, Romain; Alexandre, Joachim; Rouet, René; Manrique, Alain; Guinamard, Romain

2016-01-15

The transient receptor potential melastatin 4 (TRPM4) inhibitor 9-phenanthrol reduces action potential duration in rabbit Purkinje fibres but not in ventricle. TRPM4-like single channel activity is observed in isolated rabbit Purkinje cells but not in ventricular cells. The TRPM4-like current develops during the notch and early repolarization phases of the action potential in Purkinje cells. Transient receptor potential melastatin 4 (TRPM4) Ca(2+)-activated non-selective cation channel activity has been recorded in cardiomyocytes and sinus node cells from mammals. In addition, TRPM4 gene mutations are associated with human diseases of cardiac conduction, suggesting that TRPM4 plays a role in this aspect of cardiac function. Here we evaluate the TRPM4 contribution to cardiac electrophysiology of Purkinje fibres. Ventricular strips with Purkinje fibres were isolated from rabbit hearts. Intracellular microelectrodes recorded Purkinje fibre activity and the TRPM4 inhibitor 9-phenanthrol was applied to unmask potential TRPM4 contributions to the action potential. 9-Phenanthrol reduced action potential duration measured at the point of 50 and 90% repolarization with an EC50 of 32.8 and 36.1×10(-6) mol l(-1), respectively, but did not modulate ventricular action potentials. Inside-out patch-clamp recordings were used to monitor TRPM4 activity in isolated Purkinje cells. TRPM4-like single channel activity (conductance = 23.8 pS; equal permeability for Na(+) and K(+); sensitivity to voltage, Ca(2+) and 9-phenanthrol) was observed in 43% of patches from Purkinje cells but not from ventricular cells (0/16). Action potential clamp experiments performed in the whole-cell configuration revealed a transient inward 9-phenanthrol-sensitive current (peak density = -0.65 ± 0.15 pA pF(-1); n = 5) during the plateau phases of the Purkinje fibre action potential. These results show that TRPM4 influences action potential characteristics in rabbit Purkinje fibres and thus could modulate cardiac conduction and be involved in triggering arrhythmias. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

Catch and Patch: A Pipette-Based Approach for Automating Patch Clamp That Enables Cell Selection and Fast Compound Application.

PubMed

Danker, Timm; Braun, Franziska; Silbernagl, Nikole; Guenther, Elke

2016-03-01

Manual patch clamp, the gold standard of electrophysiology, represents a powerful and versatile toolbox to stimulate, modulate, and record ion channel activity from membrane fragments and whole cells. The electrophysiological readout can be combined with fluorescent or optogenetic methods and allows for ultrafast solution exchanges using specialized microfluidic tools. A hallmark of manual patch clamp is the intentional selection of individual cells for recording, often an essential prerequisite to generate meaningful data. So far, available automation solutions rely on random cell usage in the closed environment of a chip and thus sacrifice much of this versatility by design. To parallelize and automate the traditional patch clamp technique while perpetuating the full versatility of the method, we developed an approach to automation, which is based on active cell handling and targeted electrode placement rather than on random processes. This is achieved through an automated pipette positioning system, which guides the tips of recording pipettes with micrometer precision to a microfluidic cell handling device. Using a patch pipette array mounted on a conventional micromanipulator, our automated patch clamp process mimics the original manual patch clamp as closely as possible, yet achieving a configuration where recordings are obtained from many patch electrodes in parallel. In addition, our implementation is extensible by design to allow the easy integration of specialized equipment such as ultrafast compound application tools. The resulting system offers fully automated patch clamp on purposely selected cells and combines high-quality gigaseal recordings with solution switching in the millisecond timescale.

Micromolded PDMS planar electrode allows patch clamp electrical recordings from cells.

PubMed

Klemic, Kathryn G; Klemic, James F; Reed, Mark A; Sigworth, Fred J

2002-06-01

The patch clamp method measures membrane currents at very high resolution when a high-resistance 'gigaseal' is established between the glass microelectrode and the cell membrane (Pflugers Arch. 391 (1981) 85; Neuron 8 (1992) 605). Here we describe the first use of the silicone elastomer, poly(dimethylsiloxane) (PDMS), for patch clamp electrodes. PDMS is an attractive material for patch clamp recordings. It has low dielectric loss and can be micromolded (Annu. Rev. Mat. Sci. 28 (1998) 153) into a shape that mimics the tip of the glass micropipette. Also, the surface chemistry of PDMS may be altered to mimic the hydrophilic nature of glass (J. Appl. Polym. Sci. 14 (1970) 2499; Annu. Rev. Mat. Sci. 28 (1998) 153), thereby allowing a high-resistance seal to a cell membrane. We present a planar electrode geometry consisting of a PDMS partition with a small aperture sealed between electrode and bath chambers. We demonstrate that a planar PDMS patch electrode, after oxidation of the elastomeric surface, permits patch clamp recording on Xenopus oocytes. Our results indicate the potential for high-throughput patch clamp recording with a planar array of PDMS electrodes.

Dissipative dark matter and the Andromeda plane of satellites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Randall, Lisa; Scholtz, Jakub, E-mail: randall@physics.harvard.edu, E-mail: jscholtz@physics.harvard.edu

We show that dissipative dark matter can potentially explain the large observed mass to light ratio of the dwarf satellite galaxies that have been observed in the recently identified planar structure around Andromeda, which are thought to result from tidal forces during a galaxy merger. Whereas dwarf galaxies created from ordinary disks would be dark matter poor, dark matter inside the galactic plane not only provides a source of dark matter, but one that is more readily bound due to the dark matter's lower velocity. This initial N-body study shows that with a thin disk of dark matter inside themore » baryonic disk, mass-to-light ratios as high as O(90) can be generated when tidal forces pull out patches of sizes similar to the scales of Toomre instabilities of the dark disk. A full simulation will be needed to confirm this result.« less

Mechanosensitive Ca²⁺-permeable channels in human leukemic cells: pharmacological and molecular evidence for TRPV2.

PubMed

Pottosin, Igor; Delgado-Enciso, Iván; Bonales-Alatorre, Edgar; Nieto-Pescador, María G; Moreno-Galindo, Eloy G; Dobrovinskaya, Oxana

2015-01-01

Mechanosensitive channels are present in almost every living cell, yet the evidence for their functional presence in T lymphocytes is absent. In this study, by means of the patch-clamp technique in attached and inside-out modes, we have characterized cationic channels, rapidly activated by membrane stretch in Jurkat T lymphoblasts. The half-activation was achieved at a negative pressure of ~50mm Hg. In attached mode, single channel currents displayed an inward rectification and the unitary conductance of ~40 pS at zero command voltage. In excised inside-out patches the rectification was transformed to an outward one. Mechanosensitive channels weakly discriminated between mono- and divalent cations (PCa/PNa~1) and were equally permeable for Ca²⁺ and Mg²⁺. Pharmacological analysis showed that the mechanosensitive channels were potently blocked by amiloride (1mM) and Gd³⁺ (10 μM) in a voltage-dependent manner. They were also almost completely blocked by ruthenium red (1 μM) and SKF 96365 (250 μM), inhibitors of transient receptor potential vanilloid 2 (TRPV2) channels. At the same time, the channels were insensitive to 2-aminoethoxydiphenyl borate (2-APB, 100 μM) or N-(p-amylcinnamoyl)anthranilic acid (ACA, 50 μM), antagonists of transient receptor potential canonical (TRPC) or transient receptor potential melastatin (TRPM) channels, respectively. Human TRPV2 siRNA virtually abolished the stretch-activated current. TRPV2 are channels with multifaceted functions and regulatory mechanisms, with potentially important roles in the lymphocyte Ca²⁺ signaling. Implications of their regulation by mechanical stress are discussed in the context of lymphoid cells functions. Copyright © 2014 Elsevier B.V. All rights reserved.

Preparation of Drosophila central neurons for in situ patch clamping.

PubMed

Ryglewski, Stefanie; Duch, Carsten

2012-10-15

Short generation times and facile genetic techniques make the fruit fly Drosophila melanogaster an excellent genetic model in fundamental neuroscience research. Ion channels are the basis of all behavior since they mediate neuronal excitability. The first voltage gated ion channel cloned was the Drosophila voltage gated potassium channel Shaker(1,2). Toward understanding the role of ion channels and membrane excitability for nervous system function it is useful to combine powerful genetic tools available in Drosophila with in situ patch clamp recordings. For many years such recordings have been hampered by the small size of the Drosophila CNS. Furthermore, a robust sheath made of glia and collagen constituted obstacles for patch pipette access to central neurons. Removal of this sheath is a necessary precondition for patch clamp recordings from any neuron in the adult Drosophila CNS. In recent years scientists have been able to conduct in situ patch clamp recordings from neurons in the adult brain(3,4) and ventral nerve cord of embryonic(5,6), larval(7,8,9,10), and adult Drosophila(11,12,13,14). A stable giga-seal is the main precondition for a good patch and depends on clean contact of the patch pipette with the cell membrane to avoid leak currents. Therefore, for whole cell in situ patch clamp recordings from adult Drosophila neurons must be cleaned thoroughly. In the first step, the ganglionic sheath has to be treated enzymatically and mechanically removed to make the target cells accessible. In the second step, the cell membrane has to be polished so that no layer of glia, collagen or other material may disturb giga-seal formation. This article describes how to prepare an identified central neuron in the Drosophila ventral nerve cord, the flight motoneuron 5 (MN5(15)), for somatic whole cell patch clamp recordings. Identification and visibility of the neuron is achieved by targeted expression of GFP in MN5. We do not aim to explain the patch clamp technique itself.

Regulation of lysosomal ion homeostasis by channels and transporters.

PubMed

Xiong, Jian; Zhu, Michael X

2016-08-01

Lysosomes are the major organelles that carry out degradation functions. They integrate and digest materials compartmentalized by endocytosis, phagocytosis or autophagy. In addition to more than 60 hydrolases residing in the lysosomes, there are also ion channels and transporters that mediate the flux or transport of H(+), Ca(2+), Na(+), K(+), and Cl(-) across the lysosomal membranes. Defects in ionic exchange can lead to abnormal lysosome morphology, defective vesicle trafficking, impaired autophagy, and diseases such as neurodegeneration and lysosomal storage disorders. The latter are characterized by incomplete lysosomal digestion and accumulation of toxic materials inside enlarged intracellular vacuoles. In addition to degradation, recent studies have revealed the roles of lysosomes in metabolic pathways through kinases such as mechanistic target of rapamycin (mTOR) and transcriptional regulation through calcium signaling molecules such as transcription factor EB (TFEB) and calcineurin. Owing to the development of new approaches including genetically encoded fluorescence probes and whole endolysosomal patch clamp recording techniques, studies on lysosomal ion channels have made remarkable progress in recent years. In this review, we will focus on the current knowledge of lysosome-resident ion channels and transporters, discuss their roles in maintaining lysosomal function, and evaluate how their dysfunction can result in disease.

[Face protective patches do not reduce facial pressure ulcers in a simulated model of non-invasive ventilation].

PubMed

Riquelme M, Hugo; Wood V, David; Martínez F, Santiago; Carmona M, Fernando; Peña V, Axel; Wegner A, Adriana

2017-06-01

Noninvasive ventilation (NIV) frequently involves the development of facial pressure ulcers (FPU). Its prevention considers the empirical use of protective patches between skin and mask, in order to reduce the pressure exerted by it. To evaluate the effect of protective patches on the pressure exerted by the facial mask, and its impact on the programmed ventilatory parameters. Bilevel NIV simulated model using full face mask in phantom with a physiological airway (ALS PRO +) in supine position. Forehead, chin and cheekbones pressure were measured using 3 types of standard protective patches versus a control group using pressure sensors (Interlinks Electronics®). The values obtained with the protective patches-mask model were evaluated in the programmed variables maximum inspiratory flow (MIF)), expired tidal volume (Vte) and positive inspiratory pressure (IPAP), with Trilogy 100 ventilator, Respironics®. The programming and recording of the variables was carried out in 8 opportunities in each group by independent operators. There was no decrease in facial pressure with any of the protective patches compared to the control group. Moltopren increased facial pressure at all support points (p < 0.001), increased leakage, it decreased MIF, Vte and IPAP (p < 0.001). Hydrocolloid patches increased facial pressure only in the left cheekbone, increased leakage and decreased MIF. Polyurethane patches did not produce changes in facial pressure or ventilatory variables. The use of protective patches of moltopren, hydrocolloid and polyurethane transparent did not contribute to the decrease of the facial pressure. A deleterious effect of the moltopren and hydrocolloid patches was observed on the administration of ventilatory variables, concluding that the non-use of the protective patches allowed a better administration of the programmed parameters.

Giga-seal formation alters properties of sodium channels of human myoballs.

PubMed

Fahlke, C; Rüdel, R

1992-03-01

The influence of giga-seal formation on the properties of the Na+ channels within the covered membrane patch was investigated with a whole-cell pipette and a patch pipette applied to the same cell. Current kinetics, current/voltage relation and channel densities were determined in three combinations: (i) voltage-clamping and current recording with the whole-cell pipette, (ii) voltage-clamping with the whole-cell pipette and current recording with the patch pipette and, (iii) voltage-clamping and current recording with the patch pipette. The Hodgkin-Huxley (1952) parameters tau m and tau h were smaller for the patch currents than for the whole cell, and the h infinity curve was shifted in the negative direction. The channel density was of the order of 10 times smaller. All effects were independent of the extracellular Ca2+ concentration. The capacitive current generated in the patch by the whole-cell Na+ current and its effect on the transmembrane voltage of the patch were evaluated. The kinetic parameters of the Na+ channels in the patch did not depend on whether the voltage was clamped with the whole-cell pipette or the patch pipette. Thus, the results are not due to spurious voltage.

The pore properties of human nociceptor channel TRPA1 evaluated in single channel recordings

PubMed Central

Bobkov, Y.V.; Corey, E.A.; Ache, B.W.

2011-01-01

TRPA channels detect stimuli of different sensory modalities, including a broad spectrum of chemosensory stimuli, noxious stimuli associated with tissue damage and inflammation, mechanical stimuli, and thermal stimuli. Despite a growing understanding of potential modulators, agonists, and antagonists for these channels, the exact mechanisms of channel regulation and activation remain mostly unknown or controversial and widely debated. Relatively little is also known about the basic biophysical parameters of both native and heterologously expressed TRPA channels. Here we use conventional single channel inside-out and outside-out patch recording from the human TRPA1 channel transiently expressed in human embryonic kidney 293T cells to characterize the selectivity of the channel for inorganic mono-/divalent and organic monovalent cations in the presence of Allylisothiocyanate (AITC). We show the relative permeability of the hTRPA1 channel to inorganic cations to be: Ca2+(5.1)>Ba2+(3.5)>Mg2+(2.8)>NH4+(1.5)>Li+(1.2)>Na+(1.0)≥K+(0.98)≥Rb+(0.98)>Cs+(0.95); and to organic cations: Na+(1.0)≥Dimethylamine(0.99)>Trimethylamine(0.7)>Tetramethylammonium(0.4)>N-methyl-d-glucamine(0.1). Activation of the hTRPA1 channels by AITC appears to recruit the channels to a conformational state with an increased permeability to large organic cations. The pore of the channels in this state can be characterized as dilated by approximately 1–2.5A. These findings provide important insight into the basic fundamental properties and function of TRPA1 channels in general and human TRPA1 channel in particular. PMID:21195050

Diadenosine tetraphosphate-gating of cardiac K(ATP) channels requires intact actin cytoskeleton.

PubMed

Jovanović, S; Jovanović, A

2001-09-01

Diadenosine polyphosphates (ApnA) have been recently discovered in the heart, and their levels found to be regulated by ischemia. These signaling molecules are believed to regulate cellular processes that alarm a cell to metabolic stress. In particular, changes in cardiac diadenosine polyphosphates (ApnA) levels may contribute to the regulation of ATP-sensitive K+ (K(ATP)) channel activity, an ion channel that couples the cellular metabolic state with membrane excitability. A feature of myocardial ischemia is the disruption of the actin cytoskeleton which critically regulates the behavior of K(ATP) channels. Whether the integrity of actin microfilaments regulates the interaction of ApnA with K(ATP) channels is not known. The inside-out configuration of the patch-clamp technique was applied to cardiomyocytes isolated from guinea-pig heart. Following patch excision, the prototype dinucleotide, diadenosine tetraphosphate (Ap4A), inhibited K(ATP) channel opening. Treatment of the internal side of membrane patches with either cytochalasin B or DNase I, disrupters of the actin cytoskeleton, prevented Ap4A-induced inhibition of K(ATP) channel opening. Application of purified actin to DNase-treated membrane patches restored the ability of Ap4A to close K(ATP) channels. This study shows that inhibition of cardiac K(ATP) channel by Ap4A, a putative alarmone, requires intact subsarcolemmal actin network. Such interaction between K(ATP) channels, the cardiomyocyte cytoskeleton and intracellular Ap4A could affect different channel-dependent functions.

Noble Gas Xenon Is a Novel Adenosine Triphosphate-sensitive Potassium Channel Opener

PubMed Central

Bantel, Carsten; Maze, Mervyn; Trapp, Stefan

2010-01-01

Background Adenosine triphosphate-sensitive potassium (KATP) channels in brain are involved in neuroprotective mechanisms. Pharmacologic activation of these channels is seen as beneficial, but clinical exploitation by using classic K+ channel openers is hampered by their inability to cross the blood–brain barrier. This is different with the inhalational anesthetic xenon, which recently has been suggested to activate KATP channels; it partitions freely into the brain. Methods To evaluate the type and mechanism of interaction of xenon with neuronal-type KATP channels, these channels, consisting of Kir6.2 pore-forming subunits and sulfonylurea receptor-1 regulatory subunits, were expressed in HEK293 cells and whole cell, and excised patch-clamp recordings were performed. Results Xenon, in contrast to classic KATP channel openers, acted directly on the Kir6.2 subunit of the channel. It had no effect on the closely related, adenosine triphosphate (ATP)-regulated Kir1.1 channel and failed to activate an ATP-insensitive mutant version of Kir6.2. Furthermore, concentration–inhibition curves for ATP obtained from inside-out patches in the absence or presence of 80% xenon revealed that xenon reduced the sensitivity of the KATP channel to ATP. This was reflected in an approximately fourfold shift of the concentration causing half-maximal inhibition (IC50) from 26 ± 4 to 96 ± 6 μm. Conclusions Xenon represents a novel KATP channel opener that increases KATP currents independently of the sulfonylurea receptor-1 subunit by reducing ATP inhibition of the channel. Through this action and by its ability to readily partition across the blood–brain barrier, xenon has considerable potential in clinical settings of neuronal injury, including stroke. PMID:20179498

PA-6 inhibits inward rectifier currents carried by V93I and D172N gain-of-function KIR2.1 channels, but increases channel protein expression.

PubMed

Ji, Yuan; Veldhuis, Marlieke G; Zandvoort, Jantien; Romunde, Fee L; Houtman, Marien J C; Duran, Karen; van Haaften, Gijs; Zangerl-Plessl, Eva-Maria; Takanari, Hiroki; Stary-Weinzinger, Anna; van der Heyden, Marcel A G

2017-07-15

The inward rectifier potassium current I K1 contributes to a stable resting membrane potential and phase 3 repolarization of the cardiac action potential. KCNJ2 gain-of-function mutations V93I and D172N associate with increased I K1 , short QT syndrome type 3 and congenital atrial fibrillation. Pentamidine-Analogue 6 (PA-6) is an efficient (IC 50  = 14 nM with inside-out patch clamp methodology) and specific I K1 inhibitor that interacts with the cytoplasmic pore region of the K IR 2.1 ion channel, encoded by KCNJ2. At 10 μM, PA-6 increases wild-type (WT) K IR 2.1 expression in HEK293T cells upon chronic treatment. We hypothesized that PA-6 will interact with and inhibit V93I and D172N K IR 2.1 channels, whereas impact on channel expression at the plasma membrane requires higher concentrations. Molecular modelling was performed with the human K IR 2.1 closed state homology model using FlexX. WT and mutant K IR 2.1 channels were expressed in HEK293 cells. Patch-clamp single cell electrophysiology measurements were performed in the whole cell and inside-out mode of the patch clamp method. K IR 2.1 expression level and localization were determined by western blot analysis and immunofluorescence microscopy, respectively. PA-6 docking in the V93I/D172N double mutant homology model of K IR 2.1 demonstrated that mutations and drug-binding site are >30 Å apart. PA-6 inhibited WT and V93I outward currents with similar potency (IC 50  = 35.5 and 43.6 nM at +50 mV for WT and V93I), whereas D172N currents were less sensitive (IC 50  = 128.9 nM at +50 mV) using inside-out patch-clamp electrophysiology. In whole cell mode, 1 μM of PA-6 inhibited outward I K1 at -50 mV by 28 ± 36%, 18 ± 20% and 10 ± 6%, for WT, V93I and D172N channels respectively. Western blot analysis demonstrated that PA-6 (5 μM, 24 h) increased K IR 2.1 expression levels of WT (6.3 ± 1.5 fold), and V93I (3.9 ± 0.9) and D172N (4.8 ± 2.0) mutants. Immunofluorescent microscopy demonstrated dose-dependent intracellular K IR 2.1 accumulation following chronic PA-6 application (24 h, 1 and 5 μM). 1) KCNJ2 gain-of-function mutations V93I and D172N in the K IR 2.1 ion channel do not impair PA-6 mediated inhibition of I K1 , 2) PA-6 elevates K IR 2.1 protein expression and induces intracellular K IR 2.1 accumulation, 3) PA-6 is a strong candidate for further preclinical evaluation in treatment of congenital SQT3 and AF.

Flow characterization and patch clamp dose responses using jet microfluidics in a tubeless microfluidic device.

PubMed

Resto, Pedro J; Bhat, Abhishek; Stava, Eric; Lor, Chong; Merriam, Elliot; Diaz-Rivera, Ruben E; Pearce, Robert; Blick, Robert; Williams, Justin C

2017-11-01

Surface tension passive pumping is a way to actuate flow without the need for pumps, tubing or valves by using the pressure inside small drop to move liquid via a microfluidic channel. These types of tubeless devices have typically been used in cell biology. Herein we present the use of tubeless devices as a fluid exchange platform for patch clamp electrophysiology. Inertia from high-speed droplets and jets is used to create flow and perform on-the-fly mixing of solutions. These are then flowed over GABA transfected HEK cells under patch in order to perform a dose response analysis. TIRF imaging and electrical recordings are used to study the fluid exchange properties of the microfluidic device, resulting in 0-90% fluid exchange times of hundreds of milliseconds. COMSOL is used to model flow and fluid exchange within the device. Patch-clamping experiments show the ability to use high-speed passive pumping and its derivatives for studying peak dose responses, but not for studying ion channel kinetics. Our system results in fluid exchange times slower than when using a standard 12-barrel application system and is not as stable as traditional methods, but it offers a new platform with added functionality. Surface tension passive pumping and tubeless devices can be used in a limited fashion for electrophysiology. Users may obtain peak dose responses but the system, in its current form, is not capable of fluid exchange fast enough to study the kinetics of most ion channels. Copyright © 2017 Elsevier B.V. All rights reserved.

Robotic Automation of In Vivo Two-Photon Targeted Whole-Cell Patch-Clamp Electrophysiology.

PubMed

Annecchino, Luca A; Morris, Alexander R; Copeland, Caroline S; Agabi, Oshiorenoya E; Chadderton, Paul; Schultz, Simon R

2017-08-30

Whole-cell patch-clamp electrophysiological recording is a powerful technique for studying cellular function. While in vivo patch-clamp recording has recently benefited from automation, it is normally performed "blind," meaning that throughput for sampling some genetically or morphologically defined cell types is unacceptably low. One solution to this problem is to use two-photon microscopy to target fluorescently labeled neurons. Combining this with robotic automation is difficult, however, as micropipette penetration induces tissue deformation, moving target cells from their initial location. Here we describe a platform for automated two-photon targeted patch-clamp recording, which solves this problem by making use of a closed loop visual servo algorithm. Our system keeps the target cell in focus while iteratively adjusting the pipette approach trajectory to compensate for tissue motion. We demonstrate platform validation with patch-clamp recordings from a variety of cells in the mouse neocortex and cerebellum. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Playback Station #2 for Cal Net and 5-day-recorder tapes

USGS Publications Warehouse

Eaton, Jerry P.

1978-01-01

A second system (Playback Station #2) has been set up to play back Cal Net 1" tapes and 5-day-recorder 1/2" tapes. As with the first playback system (Playback Station #1) the tapes are played back on a Bell and Howell VR3700B tape deck and the records are written out on a 16-channel direct-writing Siemens "0scillomink." Separate reproduce heads, tape guides, and tape tension sensor rollers are required for playing back 111 tapes and 1/2" tapes, but changing these tape deck components is a simple task that requires only a few minutes. The discriminators, patch panels, selector switches, filters, time code translators, and signal conditioning circuits for the time code translators and for the tape-speed-compensation signal are all mounted in an equipment rack that stands beside the playback tape deck. Changing playback speeds (15/16 ips or 3 3/4 ips) or changing from Cal Net tapes to 5-day-recorder tapes requires only flipping a few switches and/or changing a few patch cables on the patch panel (in addition to changing the reproduce heads, etc., to change from 1" tape to 1/2" tape). For the Cal Net tapes, the system provides for playback of 9 data channels (680 Hz thru 3060 Hz plus 400 Hz) and 3 time signals (IRIG-E, IRIG-C, and WWVB) at both 15/16 ips (x1 speed) and 3 3/4 ips (x4 speed). Available modes of compensation (using either a 4688 Hz reference or a 3125 Hz reference) are subtractive, capstan, capstan plus subtractive, or no compensation.

Whole-Cell Electrical Activity Under Direct Mechanical Stimulus by AFM Cantilever Using Planar Patch Clamp Chip Approach

PubMed Central

Upadhye, Kalpesh V.; Candiello, Joseph E.; Davidson, Lance A.; Lin, Hai

2011-01-01

Patch clamp is a powerful tool for studying the properties of ion-channels and cellular membrane. In recent years, planar patch clamp chips have been fabricated from various materials including glass, quartz, silicon, silicon nitride, polydimethyl-siloxane (PDMS), and silicon dioxide. Planar patch clamps have made automation of patch clamp recordings possible. However, most planar patch clamp chips have limitations when used in combination with other techniques. Furthermore, the fabrication methods used are often expensive and require specialized equipments. An improved design as well as fabrication and characterization of a silicon-based planar patch clamp chip are described in this report. Fabrication involves true batch fabrication processes that can be performed in most common microfabrication facilities using well established MEMS techniques. Our planar patch clamp chips can form giga-ohm seals with the cell plasma membrane with success rate comparable to existing patch clamp techniques. The chip permits whole-cell voltage clamp recordings on variety of cell types including Chinese Hamster Ovary (CHO) cells and pheochromocytoma (PC12) cells, for times longer than most available patch clamp chips. When combined with a custom microfluidics chamber, we demonstrate that it is possible to perfuse the extra-cellular as well as intra-cellular buffers. The chamber design allows integration of planar patch clamp with atomic force microscope (AFM). Using our planar patch clamp chip and microfluidics chamber, we have recorded whole-cell mechanosensitive (MS) currents produced by directly stimulating human keratinocyte (HaCaT) cells using an AFM cantilever. Our results reveal the spatial distribution of MS ion channels and temporal details of the responses from MS channels. The results show that planar patch clamp chips have great potential for multi-parametric high throughput studies of ion channel proteins. PMID:22174731

Dopamine alters glutamate receptor desensitization in retinal horizontal cells of the perch (Perca fluviatilis).

PubMed Central

Schmidt, K F; Kruse, M; Hatt, H

1994-01-01

The patch-clamp technique in combination with a fast liquid filament application system was used to study the effect of dopamine on the glutamate receptor desensitization in horizontal cells of the perch (Perca fluviatilis). Kinetics of ligand-gated ion channels in fish horizontal cells are modulated by dopamine. This modulation is presumably mediated by a cAMP-dependent protein phosphorylation. Before incubation with dopamine, the glutamate receptors of horizontal cells activate and desensitize with fast time constants. In the whole-cell recording mode, fast application of the agonists L-glutamate, quisqualate, or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid prior to the dopamine incubation gives rise to fast transient currents with peak values of about 200 pA that desensitize within 100 ms. Kainate as agonist produced higher steady-state currents but no transient currents. After incubation of the cells with dopamine for 3 min, the desensitization was significantly reduced and the agonists L-glutamate, quisqualate, or alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid induced steady-state currents with amplitudes that were similar to the previously observed transient currents. Kainate-induced currents were only slightly affected. Fast desensitizing currents upon fast application of L-glutamate were also recorded from outside-out patches that were excised from horizontal cells before incubation with dopamine. The currents from excised patches desensitized to a steady-state level of about 0.2 of the peak amplitude with time constants of less than 2 ms. When the outside-out patches were excised from cells after dopamine incubation, steady-state currents were enhanced and no transient currents were observed. The results may indicate that the dopamine-dependent modulation of glutamate-induced currents, which is presumably mediated by a protein phosphorylation, is due to an alteration of the desensitization of the glutamate receptors. PMID:7520178

Response of the larger protozooplankton to an iron-induced phytoplankton bloom in the Polar Frontal Zone of the Southern Ocean (EisenEx)

NASA Astrophysics Data System (ADS)

Henjes, Joachim; Assmy, Philipp; Klaas, Christine; Smetacek, Victor

2007-05-01

The responses of larger (>50 μm in diameter) protozooplankton groups to a phytoplankton bloom induced by in situ iron fertilization (EisenEx) in the Polar Frontal Zone (PFZ) of the Southern Ocean in austral spring are presented. During the 21 days of the experiment, samples were collected from seven discrete depths in the upper 150 m inside and outside the fertilized patch for the enumeration of acantharia, foraminifera, radiolaria, heliozoa, tintinnid ciliates and aplastidic thecate dinoflagellates. Inside the patch, acantharian numbers increased twofold, but only negligibly in surrounding waters. This finding is of major interest, since acantharia are suggested to be involved in the formation of barite (BaSO 4), a palaeoindicator of both ancient and modern high-productivity regimes. Foraminifera increased significantly in abundance inside and outside the fertilized patch. However, the marked increase of juveniles after a full-moon event suggests a lunar periodicity in the reproduction cycle of some foraminiferan species rather than a reproductive response to enhanced food availability. In contrast, adult radiolaria showed no clear trend during the experiment, but juveniles increased threefold, indicating elevated reproduction. Aplastidic thecate dinoflagellates almost doubled in numbers and biomass but also increased outside the patch. Tintinnid numbers decreased twofold, although biomass remained constant because of a shift in the size spectrum. Empty tintinnid loricae, however, increased by a factor of two, indicating that grazing pressure on this group mainly by copepods, intensified during EisenEx. The results show that iron-fertilization experiments can shed light on the biology and the role of these larger protists in pelagic ecosystem, which will improve their use as proxies in paleoceanography.

The neurophysiology of figure-ground segregation in primary visual cortex.

PubMed

Lamme, V A

1995-02-01

The activity of neurons in the primary visual cortex of the awake macaque monkey was recorded while the animals were viewing full screen arrays of either oriented line segments or moving random dots. A square patch of the screen was made to perceptually pop out as a circumscribed figure by virtue of differences between the orientation or the direction of motion of the texture elements within that patch and the surround. The animals were trained to identify the figure patches by making saccadic eye movements towards their positions. Almost every cell gave a significantly larger response to elements belonging to the figure than to similar elements belonging to the background. The figure-ground response enhancement was present along the entire extent of the patch and was absent as soon as the receptive field was outside the patch. The strength of the effect had no relation with classical receptive field properties like orientation or direction selectivity or receptive field size. The response enhancement had a latency of 30-40 msec relative to the onset of the neuronal response itself. The results show that context modulation within primary visual cortex has a highly sophisticated nature, putting the image features the cells are responding to into their fully evaluated perceptual context.

Updated WORF patch

NASA Image and Video Library

2012-08-16

This patch represents the essential elements associated with pressurized Earth science research aboard the International Space Station. At the top of the patch Klingon script spells out the acronym WORF making reference to the famed Star Trek character of the same name. In doing so it attests to the foresight, honor, integrity, and persistence of all those who made the WORF possible. To the right of the Klingon script is a single four pointed star in the form of a cross to honor the late Dr. Jack Estes and Dr. Dave Amsbury, the individuals most responsible for seeing to it that an optical quality, Earth science research window was added to the United States laboratory module, Destiny. The "flying eyeball" represents the ability of the ISS to allow scientists and astronauts to make and record continuous observations of natural and manmade processes on the surface of the Earth. The Destiny laboratory is depicted on the right of the patch above the Flag of the United States of America and highlights the position of the nadir looking, optical quality, science window in the module. The light emanating from the window from the lighted interior of the module appropriately illuminates the National Ensign for display during both day and night time. In the center of the patch, below the flying eyeball is a graphic representation of the WORF rack. A science instrument is mounted on the WORF payload shelf and is recording data of the Earth's surface through the nadir looking, science window over which the WORF rack is mounted. An astronaut represented by Mario Runco Jr., a designer, developer, and manager of the WORF and depicted as Star Trek's Mr. Spock, is to the left of the WORF rack and is shown in his flight suit with his STS-44 mission patch operating an imaging instrument, emphasizing the importance of astronaut participation to achieve the maximum scientific return from orbital research.

The pure anti-oestrogen ICI 182,780 (Faslodex™) activates large conductance Ca2+-activated K+ channels in smooth muscle

PubMed Central

Dick, Gregory M

2002-01-01

Oestrogen and tamoxifen activate large conductance Ca2+-activated K+ (BKCa) channels in smooth muscle through a non-genomic mechanism that depends on the regulatory β1 subunit and an extracellular binding site. It is unknown whether a ‘pure' anti-oestrogen such as ICI 182,780 (Faslodex™), that has no known oestrogenic properties, would have any effect on BKCa channels. Using single channel patch clamp techniques on canine colonic myocytes, the hypothesis that ICI 182,780 would activate BKCa channels was tested. ICI 182,780 increased the open probability of BKCa channels in inside-out patches with an EC50 of 1 μM. These data suggest that molecules with the ability to bind nuclear oestrogen receptors, regardless of oestrogenic or anti-oestrogenic nature, activate BKCa channels through this nongenomic, membrane-delimited mechanism. The identity and characteristics of this putative binding site remain unclear; however, it has pharmacological similarity to oestrogen receptors α and β, as ICI 182,780 interacts with it. PMID:12145095

Two Types of Magnetic Flux Cancellation in the Solar Eruption of 2007 May 20

NASA Technical Reports Server (NTRS)

Sterlin, Alphonse C.; Moore, Ronald L.; Mason, Helen

2010-01-01

We study a solar eruption of 2007 May 20, in an effort to understand the cause of the eruption's onset. The event produced a GOES class B6.7 flare peaking at 05:56 UT, while ejecting a surge/filament and producing a coronal mass ejection (CME). We examine several data sets, including H-alpha images from the Solar Optical Telescope (SOT) on Hinode, EUV images from TRACE, and line-of-sight magnetograms from SOHO/MDI. Flux cancelation occurs among two different sets of flux elements inside of the erupting active region: First, for several days prior to eruption, opposite-polarity sunspot groups inside the region move toward each other, leading to the cancelation of approximately 10^{21} Mx of flux over three days. Second, within hours prior to the eruption, positive-polarity moving magnetic features (MMFs) flowing out of the positive-flux spots at approximately 1 kilometer per second repeatedly cancel with field inside a patch of negative-polarity flux located north of the sunspots. The filament erupts as a surge whose base is rooted in the location where the MMF cancelation occurs, while during the eruption that filament flows out along the polarity inversion line between the converging spot groups. We conclude that a plausible scenario is that the converging spot fields brought the magnetic region to the brink of instability, and the MMF cancelation pushed the system "over the edge." triggering the eruption.

Aniracetam reduces glutamate receptor desensitization and slows the decay of fast excitatory synaptic currents in the hippocampus.

PubMed Central

Isaacson, J S; Nicoll, R A

1991-01-01

Aniracetam is a nootropic drug that has been shown to selectively enhance quisqualate receptor-mediated responses in Xenopus oocytes injected with brain mRNA and in hippocampal pyramidal cells [Ito, I., Tanabe, S., Kohda, A. & Sugiyama, H. (1990) J. Physiol. (London) 424, 533-544]. We have used patch clamp recording techniques in hippocampal slices to elucidate the mechanism for this selective action. We find that aniracetam enhances glutamate-evoked currents in whole-cell recordings and, in outside-out patches, strongly reduces glutamate receptor desensitization. In addition, aniracetam selectively prolongs the time course and increases the peak amplitude of fast synaptic currents. These findings indicate that aniracetam slows the kinetics of fast synaptic transmission and are consistent with the proposal [Trussell, L. O. & Fischbach, G. D. (1989) Neuron 3, 209-218; Tang, C.-M., Dichter, M. & Morad, M. (1989) Science 243, 1474-1477] that receptor desensitization governs the strength of fast excitatory synaptic transmission in the brain. PMID:1660156

Aniracetam reduces glutamate receptor desensitization and slows the decay of fast excitatory synaptic currents in the hippocampus.

PubMed

Isaacson, J S; Nicoll, R A

1991-12-01

Aniracetam is a nootropic drug that has been shown to selectively enhance quisqualate receptor-mediated responses in Xenopus oocytes injected with brain mRNA and in hippocampal pyramidal cells [Ito, I., Tanabe, S., Kohda, A. & Sugiyama, H. (1990) J. Physiol. (London) 424, 533-544]. We have used patch clamp recording techniques in hippocampal slices to elucidate the mechanism for this selective action. We find that aniracetam enhances glutamate-evoked currents in whole-cell recordings and, in outside-out patches, strongly reduces glutamate receptor desensitization. In addition, aniracetam selectively prolongs the time course and increases the peak amplitude of fast synaptic currents. These findings indicate that aniracetam slows the kinetics of fast synaptic transmission and are consistent with the proposal [Trussell, L. O. & Fischbach, G. D. (1989) Neuron 3, 209-218; Tang, C.-M., Dichter, M. & Morad, M. (1989) Science 243, 1474-1477] that receptor desensitization governs the strength of fast excitatory synaptic transmission in the brain.

Structural basis of drugs that increase cardiac inward rectifier Kir2.1 currents.

PubMed

Gómez, Ricardo; Caballero, Ricardo; Barana, Adriana; Amorós, Irene; De Palm, Sue-Haida; Matamoros, Marcos; Núñez, Mercedes; Pérez-Hernández, Marta; Iriepa, Isabel; Tamargo, Juan; Delpón, Eva

2014-11-01

We hypothesize that some drugs, besides flecainide, increase the inward rectifier current (IK1) generated by Kir2.1 homotetramers (IKir2.1) and thus, exhibit pro- and/or antiarrhythmic effects particularly at the ventricular level. To test this hypothesis, we analysed the effects of propafenone, atenolol, dronedarone, and timolol on Kir2.x channels. Currents were recorded with the patch-clamp technique using whole-cell, inside-out, and cell-attached configurations. Propafenone (0.1 nM-1 µM) did not modify either IK1 recorded in human right atrial myocytes or the current generated by homo- or heterotetramers of Kir2.2 and 2.3 channels recorded in transiently transfected Chinese hamster ovary cells. On the other hand, propafenone increased IKir2.1 (EC50 = 12.0 ± 3.0 nM) as a consequence of its interaction with Cys311, an effect which decreased inward rectification of the current. Propafenone significantly increased mean open time and opening frequency at all the voltages tested, resulting in a significant increase of the mean open probability of the channel. Timolol, which interacted with Cys311, was also able to increase IKir2.1. On the contrary, neither atenolol nor dronedarone modified IKir2.1. Molecular modelling of the Kir2.1-drugs interaction allowed identification of the pharmacophore of drugs that increase IKir2.1. Kir2.1 channels exhibit a binding site determined by Cys311 that is responsible for drug-induced IKir2.1 increase. Drug binding decreases channel affinity for polyamines and current rectification, and can be a mechanism of drug-induced pro- and antiarrhythmic effects not considered until now. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

Fast, Capacious Disk Memory Device

NASA Technical Reports Server (NTRS)

Muller, Ronald M.

1990-01-01

Device for recording digital data on, and playing back data from, memory disks has high recording or playback rate and utilizes available recording area more fully. Two disks, each with own reading/writing head, used to record data at same time. Head on disk A operates on one of tracks numbered from outside in; head on disk B operates on track of same number in sequence from inside out. Underlying concept of device applicable to magnetic or optical disks.

Patch test reactions to mite antigens: a GERDA multicentre study. Groupe d'Etudes et de Recherches en Dermato-Allergie.

PubMed

Castelain, M; Birnbaum, J; Castelain, P Y; Ducombs, G; Grosshans, E; Jelen, G; Lacroix, M; Meynadier, J; Mougeolle, J M; Lachapelle, J M

1993-11-01

We performed patch tests with Dermatophagoides pteronyssinus (Dp) antigens from 2 different sources in 355 non-randomly selected patients with atopic dermatitis (AD) and 398 subjects of a control group. The study demonstrated that contact sensitization to mites occurred in an appreciable % of AD cases (20.8%), using commonly available assay products. The differences recorded between the 2 materials tested were related to the concentration of P1 antigen. Non-atopic patients rarely showed positive reactions to Dp (0.75%), when strict criteria for readings were applied and if 2 readings were performed. Patients with positive patch tests did not necessarily show positive immediate skin tests. It would be useful to carry out tests systematically in atopic patients, even if it is not yet known what modern treatment would be best for the patient. Laboratories still do not provide standardized house dust mite preparations--measuring and codifying their biological activity--for use in patch tests. It is to be hoped that the extension of this type of test will lead to the production of better test materials, in syringes with homogeneous dispersion and concentration.

A patch-based pseudo-CT approach for MRI-only radiotherapy in the pelvis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andreasen, Daniel, E-mail: dana@dtu.dk

Purpose: In radiotherapy based only on magnetic resonance imaging (MRI), knowledge about tissue electron densities must be derived from the MRI. This can be achieved by converting the MRI scan to the so-called pseudo-computed tomography (pCT). An obstacle is that the voxel intensities in conventional MRI scans are not uniquely related to electron density. The authors previously demonstrated that a patch-based method could produce accurate pCTs of the brain using conventional T{sub 1}-weighted MRI scans. The method was driven mainly by local patch similarities and relied on simple affine registrations between an atlas database of the co-registered MRI/CT scan pairsmore » and the MRI scan to be converted. In this study, the authors investigate the applicability of the patch-based approach in the pelvis. This region is challenging for a method based on local similarities due to the greater inter-patient variation. The authors benchmark the method against a baseline pCT strategy where all voxels inside the body contour are assigned a water-equivalent bulk density. Furthermore, the authors implement a parallelized approximate patch search strategy to speed up the pCT generation time to a more clinically relevant level. Methods: The data consisted of CT and T{sub 1}-weighted MRI scans of 10 prostate patients. pCTs were generated using an approximate patch search algorithm in a leave-one-out fashion and compared with the CT using frequently described metrics such as the voxel-wise mean absolute error (MAE{sub vox}) and the deviation in water-equivalent path lengths. Furthermore, the dosimetric accuracy was tested for a volumetric modulated arc therapy plan using dose–volume histogram (DVH) point deviations and γ-index analysis. Results: The patch-based approach had an average MAE{sub vox} of 54 HU; median deviations of less than 0.4% in relevant DVH points and a γ-index pass rate of 0.97 using a 1%/1 mm criterion. The patch-based approach showed a significantly better performance than the baseline water pCT in almost all metrics. The approximate patch search strategy was 70x faster than a brute-force search, with an average prediction time of 20.8 min. Conclusions: The authors showed that a patch-based method based on affine registrations and T{sub 1}-weighted MRI could generate accurate pCTs of the pelvis. The main source of differences between pCT and CT was positional changes of air pockets and body outline.« less

Comparison of diagnostic value using a small, single channel, P-wave centric sternal ECG monitoring patch with a standard 3-lead Holter system over 24 hours.

PubMed

Smith, Warren M; Riddell, Fiona; Madon, Morag; Gleva, Marye J

2017-03-01

To compare simultaneous recordings from an external patch system specifically designed to ensure better P-wave recordings and standard Holter monitor to determine diagnostic efficacy. Holter monitors are a mainstay of clinical practice, but are cumbersome to access and wear and P-wave signal quality is frequently inadequate. This study compared the diagnostic efficacy of the P-wave centric electrocardiogram (ECG) patch (Carnation Ambulatory Monitor) to standard 3-channel (leads V1, II, and V5) Holter monitor (Northeast Monitoring, Maynard, MA). Patients were referred to a hospital Holter clinic for standard clinical indications. Each patient wore both devices simultaneously and served as their own control. Holter and Patch reports were read in a blinded fashion by experienced electrophysiologists unaware of the findings in the other corresponding ECG recording. All patients, technicians, and physicians completed a questionnaire on comfort and ease of use, and potential complications. In all 50 patients, the P-wave centric patch recording system identified rhythms in 23 patients (46%) that altered management, compared to 6 Holter patients (12%), P<.001. The patch ECG intervals PR, QRS and QT correlated well with the Holter ECG intervals having correlation coefficients of 0.93, 0.86, and 0.94, respectively. Finally, 48 patients (96%) preferred wearing the patch monitor. A single-channel ambulatory patch ECG monitor, designed specifically to ensure that the P-wave component of the ECG be visible, resulted in a significantly improved rhythm diagnosis and avoided inaccurate diagnoses made by the standard 3-channel Holter monitor. Copyright © 2016 Elsevier Inc. All rights reserved.

Scalable electrophysiology in intact small animals with nanoscale suspended electrode arrays

NASA Astrophysics Data System (ADS)

Gonzales, Daniel L.; Badhiwala, Krishna N.; Vercosa, Daniel G.; Avants, Benjamin W.; Liu, Zheng; Zhong, Weiwei; Robinson, Jacob T.

2017-07-01

Electrical measurements from large populations of animals would help reveal fundamental properties of the nervous system and neurological diseases. Small invertebrates are ideal for these large-scale studies; however, patch-clamp electrophysiology in microscopic animals typically requires invasive dissections and is low-throughput. To overcome these limitations, we present nano-SPEARs: suspended electrodes integrated into a scalable microfluidic device. Using this technology, we have made the first extracellular recordings of body-wall muscle electrophysiology inside an intact roundworm, Caenorhabditis elegans. We can also use nano-SPEARs to record from multiple animals in parallel and even from other species, such as Hydra littoralis. Furthermore, we use nano-SPEARs to establish the first electrophysiological phenotypes for C. elegans models for amyotrophic lateral sclerosis and Parkinson's disease, and show a partial rescue of the Parkinson's phenotype through drug treatment. These results demonstrate that nano-SPEARs provide the core technology for microchips that enable scalable, in vivo studies of neurobiology and neurological diseases.

Patch-clamp amplifiers on a chip

PubMed Central

Weerakoon, Pujitha; Culurciello, Eugenio; Yang, Youshan; Santos-Sacchi, Joseph; Kindlmann, Peter J.; Sigworth, Fred J.

2010-01-01

We present the first, fully-integrated, two-channel implementation of a patch-clamp measurement system. With this “PatchChip” two simultaneous whole-cell recordings can be obtained with rms noise of 8 pA in a 10 kHz bandwidth. The capacitance and series-resistance of the electrode can be compensated up to 10 pF and 100 MΩ respectively under computer control. Recordings of hERG and Nav 1.7 currents demonstrate the system's capabilities, which are on par with large, commercial patch-clamp instrumentation. By reducing patch-clamp amplifiers to a millimeter size micro-chip, this work paves the way to the realization of massively-parallel, high-throughput patch-clamp systems for drug screening and ion-channel research. The PatchChip is implemented in a 0.5 μm silicon-on-sapphire process; its size is 3 × 3 mm2 and the power consumption is 5 mW per channel with a 3.3 V power supply. PMID:20637803

MATLAB-based automated patch-clamp system for awake behaving mice

PubMed Central

Siegel, Jennifer J.; Taylor, William; Chitwood, Raymond A.; Johnston, Daniel

2015-01-01

Automation has been an important part of biomedical research for decades, and the use of automated and robotic systems is now standard for such tasks as DNA sequencing, microfluidics, and high-throughput screening. Recently, Kodandaramaiah and colleagues (Nat Methods 9: 585–587, 2012) demonstrated, using anesthetized animals, the feasibility of automating blind patch-clamp recordings in vivo. Blind patch is a good target for automation because it is a complex yet highly stereotyped process that revolves around analysis of a single signal (electrode impedance) and movement along a single axis. Here, we introduce an automated system for blind patch-clamp recordings from awake, head-fixed mice running on a wheel. In its design, we were guided by 3 requirements: easy-to-use and easy-to-modify software; seamless integration of behavioral equipment; and efficient use of time. The resulting system employs equipment that is standard for patch recording rigs, moderately priced, or simple to make. It is written entirely in MATLAB, a programming environment that has an enormous user base in the neuroscience community and many available resources for analysis and instrument control. Using this system, we obtained 19 whole cell patch recordings from neurons in the prefrontal cortex of awake mice, aged 8–9 wk. Successful recordings had series resistances that averaged 52 ± 4 MΩ and required 5.7 ± 0.6 attempts to obtain. These numbers are comparable with those of experienced electrophysiologists working manually, and this system, written in a simple and familiar language, will be useful to many cellular electrophysiologists who wish to study awake behaving mice. PMID:26084901

Wearable Inset-Fed FR4 Microstrip Patch Antenna Design

NASA Astrophysics Data System (ADS)

Zaini, S. R. Mohd; Rani, K. N. Abdul

2018-03-01

This project proposes the design of a wireless body area network (WBAN) microstrip patch antenna covered by the jeans fabric as the outer layer operating at the center frequency, fc of 2.40 GHz. Precisely, the microstrip patch antenna with the inset-fed edge technique is designed and simulated systematically by using the Keysight Advanced Design System (ADS) software where the FR4 board with the dielectric constant, ɛr of 4.70, dissipation factor or loss tangent, tan δ of 0.02 and height, h of 1.60 mm is the chosen dielectric substrate. The wearable microstrip patch antenna design is then fabricated using the FR4 printed circuit board (PCB) material, hidden inside the jeans fabric, and attached to clothing, such as a jacket accordingly. Simulation and fabrication measurement results show that the designed microstrip patch antenna characteristics can be applied significantly within the industrial, scientific, and medical (ISM) radio band, which is at fc = 2.40 GHz.

Emergent Properties of Patch Shapes Affect Edge Permeability to Animals

PubMed Central

Nams, Vilis O.

2011-01-01

Animal travel between habitat patches affects populations, communities and ecosystems. There are three levels of organization of edge properties, and each of these can affect animals. At the lowest level are the different habitats on each side of an edge, then there is the edge itself, and finally, at the highest level of organization, is the geometry or structure of the edge. This study used computer simulations to (1) find out whether effects of edge shapes on animal behavior can arise as emergent properties solely due to reactions to edges in general, without the animals reacting to the shapes of the edges, and to (2) generate predictions to allow field and experimental studies to test mechanisms of edge shape response. Individual animals were modeled traveling inside a habitat patch that had different kinds of edge shapes (convex, concave and straight). When animals responded edges of patches, this created an emergent property of responding to the shape of the edge. The response was mostly to absolute width of the shapes, and not the narrowness of them. When animals were attracted to edges, then they tended to collect in convexities and disperse from concavities, and the opposite happened when animals avoided edges. Most of the responses occurred within a distance of 40% of the perceptual range from the tip of the shapes. Predictions were produced for directionality at various locations and combinations of treatments, to be used for testing edge behavior mechanisms. These results suggest that edge shapes tend to either concentrate or disperse animals, simply because the animals are either attracted to or avoid edges, with an effect as great as 3 times the normal density. Thus edge shape could affect processes like pollination, seed predation and dispersal and predator abundance. PMID:21747965

[Dynamic evaluation on landscape connectivity of ecological land: a case study of Shenzhen, Guangdong Province of South China].

PubMed

Wu, Jian-Sheng; Liu, Hong-Meng; Huang, Xiu-Lan; Feng, Zhe

2012-09-01

Ecological land is the most crucial and sensitive land use type in rapidly urbanizing areas. Landscape connectivity can help us to better understand the interactions between landscape structure and landscape function. By using the land use data of Shenzhen from 1996 to 2008 and the graph theory- based integral index of connectivity (IIC), probability index of connectivity (PC), and importance value of patches (dPC), a dynamic evaluation on the landscape connectivity of ecological land in the City was conducted, and a spatial assessment was made to identify the most important patches for maintaining overall landscape connectivity. In combining with the basic ecological controlling line in Shenzhen, the variations of the landscape connectivity of the ecological land inside and outside the basic ecological controlling line were evaluated. From 1996 to 2008, the overall landscape connectivity of the ecological land in Shenzhen displayed a downward trend, the importance and the spatial distribution of the important patches for maintaining the overall landscape connectivity changed, and the basic ecological controlling line played definite roles in maintaining the landscape connectivity of ecological land inside the line.

Preparation of Acute Brain Slices Using an Optimized N-Methyl-D-glucamine Protective Recovery Method.

PubMed

Ting, Jonathan T; Lee, Brian R; Chong, Peter; Soler-Llavina, Gilberto; Cobbs, Charles; Koch, Christof; Zeng, Hongkui; Lein, Ed

2018-02-26

This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology. With this updated approach, a substantial improvement is observed in the speed and reliability of gigaohm seal formation during targeted patch clamp recording experiments while maintaining excellent neuronal preservation, thereby facilitating challenging experimental applications. Representative results are provided from multi-neuron patch clamp recording experiments to assay synaptic connectivity in neocortical brain slices prepared from young adult transgenic mice and mature adult human neurosurgical specimens. Furthermore, the optimized NMDG protective recovery method of brain slicing is compatible with both juvenile and adult animals, thus resolving a limitation of the original methodology. In summary, a single media formulation and brain slicing procedure can be implemented across various species and ages to achieve excellent viability and tissue preservation.

Preparation of Acute Brain Slices Using an Optimized N-Methyl-D-glucamine Protective Recovery Method

PubMed Central

Chong, Peter; Soler-Llavina, Gilberto; Cobbs, Charles; Koch, Christof; Zeng, Hongkui; Lein, Ed

2018-01-01

This protocol is a practical guide to the N-methyl-D-glucamine (NMDG) protective recovery method of brain slice preparation. Numerous recent studies have validated the utility of this method for enhancing neuronal preservation and overall brain slice viability. The implementation of this technique by early adopters has facilitated detailed investigations into brain function using diverse experimental applications and spanning a wide range of animal ages, brain regions, and cell types. Steps are outlined for carrying out the protective recovery brain slice technique using an optimized NMDG artificial cerebrospinal fluid (aCSF) media formulation and enhanced procedure to reliably obtain healthy brain slices for patch clamp electrophysiology. With this updated approach, a substantial improvement is observed in the speed and reliability of gigaohm seal formation during targeted patch clamp recording experiments while maintaining excellent neuronal preservation, thereby facilitating challenging experimental applications. Representative results are provided from multi-neuron patch clamp recording experiments to assay synaptic connectivity in neocortical brain slices prepared from young adult transgenic mice and mature adult human neurosurgical specimens. Furthermore, the optimized NMDG protective recovery method of brain slicing is compatible with both juvenile and adult animals, thus resolving a limitation of the original methodology. In summary, a single media formulation and brain slicing procedure can be implemented across various species and ages to achieve excellent viability and tissue preservation. PMID:29553547

Removing ballistocardiogram (BCG) artifact from full-scalp EEG acquired inside the MR scanner with Orthogonal Matching Pursuit (OMP)

PubMed Central

Xia, Hongjing; Ruan, Dan; Cohen, Mark S.

2014-01-01

Ballistocardiogram (BCG) artifact remains a major challenge that renders electroencephalographic (EEG) signals hard to interpret in simultaneous EEG and functional MRI (fMRI) data acquisition. Here, we propose an integrated learning and inference approach that takes advantage of a commercial high-density EEG cap, to estimate the BCG contribution in noisy EEG recordings from inside the MR scanner. To estimate reliably the full-scalp BCG artifacts, a near-optimal subset (20 out of 256) of channels first was identified using a modified recording setup. In subsequent recordings inside the MR scanner, BCG-only signal from this subset of channels was used to generate continuous estimates of the full-scalp BCG artifacts via inference, from which the intended EEG signal was recovered. The reconstruction of the EEG was performed with both a direct subtraction and an optimization scheme. We evaluated the performance on both synthetic and real contaminated recordings, and compared it to the benchmark Optimal Basis Set (OBS) method. In the challenging non-event-related-potential (non-ERP) EEG studies, our reconstruction can yield more than fourteen-fold improvement in reducing the normalized RMS error of EEG signals, compared to OBS. PMID:25120421

Tyre-road friction coefficient estimation based on tyre sensors and lateral tyre deflection: modelling, simulations and experiments

NASA Astrophysics Data System (ADS)

Hong, Sanghyun; Erdogan, Gurkan; Hedrick, Karl; Borrelli, Francesco

2013-05-01

The estimation of the tyre-road friction coefficient is fundamental for vehicle control systems. Tyre sensors enable the friction coefficient estimation based on signals extracted directly from tyres. This paper presents a tyre-road friction coefficient estimation algorithm based on tyre lateral deflection obtained from lateral acceleration. The lateral acceleration is measured by wireless three-dimensional accelerometers embedded inside the tyres. The proposed algorithm first determines the contact patch using a radial acceleration profile. Then, the portion of the lateral acceleration profile, only inside the tyre-road contact patch, is used to estimate the friction coefficient through a tyre brush model and a simple tyre model. The proposed strategy accounts for orientation-variation of accelerometer body frame during tyre rotation. The effectiveness and performance of the algorithm are demonstrated through finite element model simulations and experimental tests with small tyre slip angles on different road surface conditions.

Establishment of the Dual Whole Cell Recording Patch Clamp Configuration for the Measurement of Gap Junction Conductance.

PubMed

Veenstra, Richard D

2016-01-01

The development of the patch clamp technique has enabled investigators to directly measure gap junction conductance between isolated pairs of small cells with resolution to the single channel level. The dual patch clamp recording technique requires specialized equipment and the acquired skill to reliably establish gigaohm seals and the whole cell recording configuration with high efficiency. This chapter describes the equipment needed and methods required to achieve accurate measurement of macroscopic and single gap junction channel conductances. Inherent limitations with the dual whole cell recording technique and methods to correct for series access resistance errors are defined as well as basic procedures to determine the essential electrical parameters necessary to evaluate the accuracy of gap junction conductance measurements using this approach.

Automatic polyp detection in colonoscopy videos

NASA Astrophysics Data System (ADS)

Yuan, Zijie; IzadyYazdanabadi, Mohammadhassan; Mokkapati, Divya; Panvalkar, Rujuta; Shin, Jae Y.; Tajbakhsh, Nima; Gurudu, Suryakanth; Liang, Jianming

2017-02-01

Colon cancer is the second cancer killer in the US [1]. Colonoscopy is the primary method for screening and prevention of colon cancer, but during colonoscopy, a significant number (25% [2]) of polyps (precancerous abnormal growths inside of the colon) are missed; therefore, the goal of our research is to reduce the polyp miss-rate of colonoscopy. This paper presents a method to detect polyp automatically in a colonoscopy video. Our system has two stages: Candidate generation and candidate classification. In candidate generation (stage 1), we chose 3,463 frames (including 1,718 with-polyp frames) from real-time colonoscopy video database. We first applied processing procedures, namely intensity adjustment, edge detection and morphology operations, as pre-preparation. We extracted each connected component (edge contour) as one candidate patch from the pre-processed image. With the help of ground truth (GT) images, 2 constraints were implemented on each candidate patch, dividing and saving them into polyp group and non-polyp group. In candidate classification (stage 2), we trained and tested convolutional neural networks (CNNs) with AlexNet architecture [3] to classify each candidate into with-polyp or non-polyp class. Each with-polyp patch was processed by rotation, translation and scaling for invariant to get a much robust CNNs system. We applied leave-2-patients-out cross-validation on this model (4 of 6 cases were chosen as training set and the rest 2 were as testing set). The system accuracy and sensitivity are 91.47% and 91.76%, respectively.

Large Volume In-Situ Filtration During Sofex: an Overview of Preliminary Results

NASA Astrophysics Data System (ADS)

Lam, P. J.; Wood, T. J.; Bishop, J. K.

2002-12-01

We deployed the Multiple Unit Large Volume in-situ Filtration System (MULVFS) during the Southern Ocean Iron Experiment (SOFeX) in Jan/Feb 2002 from the R/V Revelle. The MULVFS collected samples over 4 hours of pumping at depths between the surface and 1000m from 3 flow channels: size-fractionated particles (>51μm, 1-51μm, and nominally <1μm) using a 51μm polyester mesh and a pair of microquartz fiber filters (1μm) in sequence from up to 12,000L of seawater; Th samples through absorber cartridges from up to 3500L; and >0.4μm and >0.7μm particles from up to 25L. Samples were shared with several groups in SOFeX. Profiles from the North Patch (55S 172W; hereafter "55S") were collected on Julian Day 12 before the first Fe infusion, and "in the patch" on JD 19 and 40. Five profiles were collected in the South Patch (66S, 172W; hereafter "66S"): two "out of the patch" profiles on JD 24 and 34, and three "in the patch" profiles on JD 28, 31, and 35. We observed the following in the (>51μm) size fraction: 55S was initially characterized by a predominance of small particles in the mixed layer, with very little captured on the >51μm filters. Four weeks after the first Fe addition, the >51μm samples from 35m were heavily loaded. There was a clear increase in large sized organic matter in the mixed layer, but there was no visible evidence of enhanced deep particle export at this point in the experiment. Samples collected over a shorter (12 day) period at 66S showed a concurrent natural bloom outside of the patch, obscuring detection of biomass differences inside the patch. We have calculated POC in our samples using gravimetric techniques in the >51μm fraction (polyester filter) and measured directly in the 1-51 μm and "<1μm" fractions (quartz fiber filters). We will also present preliminary results of bulk chemical analyses for CaCO3, Si, and acid leacheable bioactive trace metals, with an emphasis on iron.

Dry patches in a flowing film : Predicting rewetting and the effects of inertia

NASA Astrophysics Data System (ADS)

Lebon, Luc; Sebilleau, Julien; Limat, Laurent

2016-11-01

We study the effects of inertia on the shape and stability of dry patches using liquids of decreasing viscosities. These dry patches are formed when a liquid film flows down along a substrate under partial wetting conditions. They become stationary and exhibit an "arch" shape well described by a simple viscous model developed long ago by Podgorski. Surprisingly, this "arch" shape appears to be robust when one decreases the fluid viscosity which increases inertial effects, but the evolution of the apex curvature upon flow rate is strongly affected. We here proposed an improved description of the dry patch evolution taking into account several physical effects as the hydrostatic pressure in the liquid film, the curvature of the contact line, and these inertial effects. These ones affect both the mechanical equilibrium of the rim surrounding the dry patch and the flow inside the rim. This model allows us to show that the dry patch shape remains extremely close to the viscous -Podgorski- prediction but with a rescaling of the apex curvature. It also allows us to get a better prediction of the apex curvature dependence upon flow rate and a prediction of the rewetting threshold above which dry patches are swept away by the film flow.

Ability of Impedance-Based Health Monitoring To Detect Structural Damage of Propulsion System Components Assessed

NASA Technical Reports Server (NTRS)

Martin, Richard E.; Gyekenyesi, Andrew L.; Sawicki, Jerzy T.; Baaklini, George Y.

2005-01-01

Impedance-based structural-health-monitoring uses piezoelectric (PZT) patches that are bonded onto or embedded in a structure. Each individual patch behaves as both an actuator of the surrounding structural area as well as a sensor of the structural response. The size of the excited area varies with the geometry and material composition of the structure, and an active patch is driven by a sinusoidal voltage sweep. When a PZT patch is subjected to an electric field, it produces a mechanical strain; and when it is stressed, it produces an electric charge. Since the patch is bonded to the structure, driving a patch deforms and vibrates the structure. The structure then produces a localized dynamic response. This structural system response is transferred back to the PZT patch, which in turn produces an electrical response. The electromechanical impedance method is based on the principle of electromechanical coupling between the active sensor and the structure, which allows researchers to assess local structural dynamics directly by interrogating a distributed sensor array. Because of mechanical coupling between the sensor and the host structure, this mechanical effect is picked up by the sensor and, through electromechanical coupling inside the active element, is reflected in electrical impedance measured at the sensor s terminals.

Optimizing Nanoelectrode Arrays for Scalable Intracellular Electrophysiology.

PubMed

Abbott, Jeffrey; Ye, Tianyang; Ham, Donhee; Park, Hongkun

2018-03-20

Electrode technology for electrophysiology has a long history of innovation, with some decisive steps including the development of the voltage-clamp measurement technique by Hodgkin and Huxley in the 1940s and the invention of the patch clamp electrode by Neher and Sakmann in the 1970s. The high-precision intracellular recording enabled by the patch clamp electrode has since been a gold standard in studying the fundamental cellular processes underlying the electrical activities of neurons and other excitable cells. One logical next step would then be to parallelize these intracellular electrodes, since simultaneous intracellular recording from a large number of cells will benefit the study of complex neuronal networks and will increase the throughput of electrophysiological screening from basic neurobiology laboratories to the pharmaceutical industry. Patch clamp electrodes, however, are not built for parallelization; as for now, only ∼10 patch measurements in parallel are possible. It has long been envisioned that nanoscale electrodes may help meet this challenge. First, nanoscale electrodes were shown to enable intracellular access. Second, because their size scale is within the normal reach of the standard top-down fabrication, the nanoelectrodes can be scaled into a large array for parallelization. Third, such a nanoelectrode array can be monolithically integrated with complementary metal-oxide semiconductor (CMOS) electronics to facilitate the large array operation and the recording of the signals from a massive number of cells. These are some of the central ideas that have motivated the research activity into nanoelectrode electrophysiology, and these past years have seen fruitful developments. This Account aims to synthesize these findings so as to provide a useful reference. Summing up from the recent studies, we will first elucidate the morphology and associated electrical properties of the interface between a nanoelectrode and a cellular membrane, clarifying how the nanoelectrode attains intracellular access. This understanding will be translated into a circuit model for the nanobio interface, which we will then use to lay out the strategies for improving the interface. The intracellular interface of the nanoelectrode is currently inferior to that of the patch clamp electrode; reaching this benchmark will be an exciting challenge that involves optimization of electrode geometries, materials, chemical modifications, electroporation protocols, and recording/stimulation electronics, as we describe in the Account. Another important theme of this Account, beyond the optimization of the individual nanoelectrode-cell interface, is the scalability of the nanoscale electrodes. We will discuss this theme using a recent development from our groups as an example, where an array of ca. 1000 nanoelectrode pixels fabricated on a CMOS integrated circuit chip performs parallel intracellular recording from a few hundreds of cardiomyocytes, which marks a new milestone in electrophysiology.

WMSA for wireless communication applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vats, Monika; Agarwal, Alok, E-mail: alokagarwal26@yahoo.com; Kumar, Ravindra

2016-03-09

Modified rectangular compact microstrip patch antenna having finite ground plane is proposed in this paper. Wideband Microstrip Antenna (WMSA) is achieved by corner cut and inserting air gaps inside the edges of the radiating patch having finite ground plane. The obtained impedance bandwidth for 10 dB return loss for the operating frequency f{sub 0} = 2.09 GHz is 28.7 % (600 MHz), which is very high as compared to the bandwidth obtained for the conventional microstrip antenna. Compactness with wide bandwidth of this antenna is practically useful for the wireless communication systems.

PKCɛ mediates substance P inhibition of GABAA receptors-mediated current in rat dorsal root ganglion.

PubMed

Li, Li; Zhao, Lei; Wang, Yang; Ma, Ke-tao; Shi, Wen-yan; Wang, Ying-zi; Si, Jun-qiang

2015-02-01

The mechanism underlying the modulatory effect of substance P (SP) on GABA-activated response in rat dorsal root ganglion (DRG) neurons was investigated. In freshly dissociated rat DRG neurons, whole-cell patch-clamp technique was used to record GABA-activated current and sharp electrode intracellular recording technique was used to record GABA-induced membrane depolarization. Application of GABA (1-1000 μmol/L) induced an inward current in a concentration-dependent manner in 114 out of 127 DRG neurons (89.8 %) examined with whole-cell patch-clamp recordings. Bath application of GABA (1-1000 μmol/L) evoked a depolarizing response in 236 out of 257 (91.8%) DRG neurons examined with intracellular recordings. Application of SP (0.001-1 μmol/L) suppressed the GABA-activated inward current and membrane depolarization. The inhibitory effects were concentration-dependent and could be blocked by the selective neurokinin 1 (NK1) receptors antagonist spantide but not by L659187 and SR142801 (1 μmol/L, n=7), selective antagonists of NK2 and NK3. The inhibitory effect of SP was significantly reduced by the calcium chelator BAPTA-AM, phospholipase C (PLC) inhibitor U73122, and PKC inhibitor chelerythrine, respectively. The PKA inhibitor H-89 did not affect the SP effect. Remarkably, the inhibitory effect of SP on GABA-activated current was nearly completely removed by a selective PKCε inhibitor epilon-V1-2 but not by safingol and LY333531, selective inhibitors of PKCα and PKCβ. Our results suggest that NK1 receptor mediates SP-induced inhibition of GABA-activated current and membrane depolarization by activating intracellular PLC-Ca²⁺-PKCε cascade. SP might regulate the excitability of peripheral nociceptors through inhibition of the "pre-synaptic inhibition" evoked by GABA, which may explain its role in pain and neurogenic inflammation.

Daytime VHF amplitude scintillations recorded at an Indian low-latitude station, Waltair (17.7°N, 83.3°E) during 1997-2003

NASA Astrophysics Data System (ADS)

Uma, G.; Brahmanandam, P. S.; Srinivasu, V. K. D.; Prasad, D. S. V. V. D.; Rama Rao, P. V. S.

2018-04-01

In this research, it is presented the daytime amplitude scintillations recorded at VHF frequency (244 MHz) at an Indian low-latitude station, Waltair (17.7°N, 83.3°E) during seven continuous years (1997-2003). Contrary to the nighttime scintillation seasonal trends, the occurrence of daytime scintillations maximizes during summer followed by winter and the equinox seasons. The fade depths, scintillation indices and the patch durations of daytime scintillations are meager when compared with their nighttime counterparts. A co-located digital high frequency (HF) ionosonde radar confirms the presence of sporadic (Es) layers when daytime scintillations are observed. The presence of daytime scintillations is evident when the critical frequency of the Es-layer (foEs) is ≥4 MHz and Es-layers are characterized by a highly diffuse range spread Es echoes as can be seen on ionograms. It is surmised that the gradient drift instability (GDI) seems to be the possible mechanism for the generation of these daytime scintillations. It is quite likely that the spread Es-F-layer coupling is done through polarization electric fields (Ep) that develop inside the destabilized patches of sporadic E layers, which are mapped up to the F region along the field lines as to initiate the daytime scintillations through the GDI mechanism. Further, the presence of additional stratification of ionosphere F-layer, popularly known as the F3-layer, is observed on ionograms once the Es-layers and daytime scintillations are ceased.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Min; Yu, Yun; Hu, Keke

Investigating the collisions of individual metal nanoparticles (NPs) with electrodes can provide new insights into their electrocatalytic behavior, mass transport, and interactions with surfaces. Here we report a new experimental setup for studying NP collisions based on the use of carbon nanopipettes to enable monitoring multiple collision events involving the same NP captured inside the pipet cavity. A patch clamp amplifier capable of measuring pA-range currents on the microsecond time scale with a very low noise and stable background was used to record the collision transients. The analysis of current transients produced by oxidation of hydrogen peroxide at one IrOxmore » NP provided information about the origins of deactivation of catalytic NPs and the effects of various experimental conditions on the collision dynamics. Lastly, high-resolution TEM of carbon pipettes was used to attain better understanding of the NP capture and collisions.« less

Hybrid graphene-copper UWB array sensor for brain tumor detection via scattering parameters in microwave detection system

NASA Astrophysics Data System (ADS)

Jamlos, Mohd Aminudin; Ismail, Abdul Hafiizh; Jamlos, Mohd Faizal; Narbudowicz, Adam

2017-01-01

Hybrid graphene-copper ultra-wideband array sensor applied to microwave imaging technique is successfully used in detecting and visualizing tumor inside human brain. The sensor made of graphene coated film for the patch while copper for both the transmission line and parasitic element. The hybrid sensor performance is better than fully copper sensor. Hybrid sensor recorded wider bandwidth of 2.0-10.1 GHz compared with fully copper sensor operated from 2.5 to 10.1 GHz. Higher gain of 3.8-8.5 dB is presented by hybrid sensor, while fully copper sensor stated lower gain ranging from 2.6 to 6.7 dB. Both sensors recorded excellent total efficiency averaged at 97 and 94%, respectively. The sensor used for both transmits equivalent signal and receives backscattering signal from stratified human head model in detecting tumor. Difference in the data of the scattering parameters recorded from the head model with presence and absence of tumor is used as the main data to be further processed in confocal microwave imaging algorithm in generating image. MATLAB software is utilized to analyze S-parameter signals obtained from measurement. Tumor presence is indicated by lower S-parameter values compared to higher values recorded by tumor absence.

The Global and Radial Stellar Mass Assembly of Milky Way-sized Galaxies

NASA Astrophysics Data System (ADS)

Avila-Reese, Vladimir; González-Samaniego, Alejandro; Colín, Pedro; Ibarra-Medel, Héctor; Rodríguez-Puebla, Aldo

2018-02-01

We study the global and radial stellar mass assembly of eight zoomed-in Milky Way (MW)-sized galaxies produced in hydrodynamics cosmological simulations. The disk-dominated galaxies (four) show a fast initial stellar mass growth in the innermost parts, driven mostly by in situ star formation (SF), but since z ∼ 2‑1, the SF has entered a long-term quenching phase. The outer regions follow this trend but more gently, as they are more external. As a result, the radial stellar mass growth is highly inside-out due to both inside-out structural growth and inside-out SF quenching. The half-mass radius evolves fast; for instance, {R}0.5(z = 1) < 0.5 {R}0.5 (z = 0). Two other runs resemble lenticular galaxies. One also shows a pronounced inside-out growth, and the other one presents a nearly uniform radial mass assembly. The other two galaxies suffered late major mergers. Their normalized radial mass growth histories (MGHs) are very close, but with periods of outside-in assembly during or after the mergers. For all of the simulations, the archaeological radial MGHs calculated from the z = 0 stellar particle age distribution are similar to current MGHs, which shows that the mass assembly by ex situ stars and the radial mass transport do not significantly change their radial mass distributions. Our results agree qualitatively with observational inferences from the fossil record method applied to a survey of local galaxies and from look-back observations of progenitors of MW-sized galaxies. However, the inside-out growth mode is more pronounced, and the {R}0.5 growth is faster in simulations than in observational inferences.

Patch nearfield acoustic holography combined with sound field separation technique applied to a non-free field

NASA Astrophysics Data System (ADS)

Bi, ChuanXing; Jing, WenQian; Zhang, YongBin; Xu, Liang

2015-02-01

The conventional nearfield acoustic holography (NAH) is usually based on the assumption of free-field conditions, and it also requires that the measurement aperture should be larger than the actual source. This paper is to focus on the problem that neither of the above-mentioned requirements can be met, and to examine the feasibility of reconstructing the sound field radiated by partial source, based on double-layer pressure measurements made in a non-free field by using patch NAH combined with sound field separation technique. And also, the sensitivity of the reconstructed result to the measurement error is analyzed in detail. Two experiments involving two speakers in an exterior space and one speaker inside a car cabin are presented. The experimental results demonstrate that the patch NAH based on single-layer pressure measurement cannot obtain a satisfied result due to the influences of disturbing sources and reflections, while the patch NAH based on double-layer pressure measurements can successfully remove these influences and reconstruct the patch sound field effectively.

Cargo-cult training

NASA Astrophysics Data System (ADS)

Magueijo, João

2009-12-01

Richard Feynman, in one of his famous rants, evoked as a metaphor what he called "cargo-cult science". During the Second World War, the indigenous people of the South Pacific became accustomed to US Air Force planes landing on their islands, invariably bringing a profusion of desirable goods and tasty foods. When the war ended, they were distressed by the discontinuation of this popular service. So, they decided to take action. They cleared elongated patches of land to make them look like runways. They lit wood fires where they had seen electric floodlights guiding in the planes. They built a wooden shack and made a man sit inside with two halves of a coconut on each ear and bamboo bars sticking out like antennas: he was the "air controller". And they waited for the planes to return.

An optogenetics- and imaging-assisted simultaneous multiple patch-clamp recording system for decoding complex neural circuits

PubMed Central

Wang, Guangfu; Wyskiel, Daniel R; Yang, Weiguo; Wang, Yiqing; Milbern, Lana C; Lalanne, Txomin; Jiang, Xiaolong; Shen, Ying; Sun, Qian-Quan; Zhu, J Julius

2015-01-01

Deciphering neuronal circuitry is central to understanding brain function and dysfunction, yet it remains a daunting task. To facilitate the dissection of neuronal circuits, a process requiring functional analysis of synaptic connections and morphological identification of interconnected neurons, we present here a method for stable simultaneous octuple patch-clamp recordings. This method allows physiological analysis of synaptic interconnections among 4–8 simultaneously recorded neurons and/or 10–30 sequentially recorded neurons, and it allows anatomical identification of >85% of recorded interneurons and >99% of recorded principal neurons. We describe how to apply the method to rodent tissue slices; however, it can be used on other model organisms. We also describe the latest refinements and optimizations of mechanics, electronics, optics and software programs that are central to the realization of a combined single- and two-photon microscopy–based, optogenetics- and imaging-assisted, stable, simultaneous quadruple–viguple patch-clamp recording system. Setting up the system, from the beginning of instrument assembly and software installation to full operation, can be completed in 3–4 d. PMID:25654757

Force-controlled patch clamp of beating cardiac cells.

PubMed

Ossola, Dario; Amarouch, Mohamed-Yassine; Behr, Pascal; Vörös, János; Abriel, Hugues; Zambelli, Tomaso

2015-03-11

From its invention in the 1970s, the patch clamp technique is the gold standard in electrophysiology research and drug screening because it is the only tool enabling accurate investigation of voltage-gated ion channels, which are responsible for action potentials. Because of its key role in drug screening, innovation efforts are being made to reduce its complexity toward more automated systems. While some of these new approaches are being adopted in pharmaceutical companies, conventional patch-clamp remains unmatched in fundamental research due to its versatility. Here, we merged the patch clamp and atomic force microscope (AFM) techniques, thus equipping the patch-clamp with the sensitive AFM force control. This was possible using the FluidFM, a force-controlled nanopipette based on microchanneled AFM cantilevers. First, the compatibility of the system with patch-clamp electronics and its ability to record the activity of voltage-gated ion channels in whole-cell configuration was demonstrated with sodium (NaV1.5) channels. Second, we showed the feasibility of simultaneous recording of membrane current and force development during contraction of isolated cardiomyocytes. Force feedback allowed for a gentle and stable contact between AFM tip and cell membrane enabling serial patch clamping and injection without apparent cell damage.

The Touch and Zap method for in vivo whole-cell patch recording of intrinsic and visual responses of cortical neurons and glial cells.

PubMed

Schramm, Adrien E; Marinazzo, Daniele; Gener, Thomas; Graham, Lyle J

2014-01-01

Whole-cell patch recording is an essential tool for quantitatively establishing the biophysics of brain function, particularly in vivo. This method is of particular interest for studying the functional roles of cortical glial cells in the intact brain, which cannot be assessed with extracellular recordings. Nevertheless, a reasonable success rate remains a challenge because of stability, recording duration and electrical quality constraints, particularly for voltage clamp, dynamic clamp or conductance measurements. To address this, we describe "Touch and Zap", an alternative method for whole-cell patch clamp recordings, with the goal of being simpler, quicker and more gentle to brain tissue than previous approaches. Under current clamp mode with a continuous train of hyperpolarizing current pulses, seal formation is initiated immediately upon cell contact, thus the "Touch". By maintaining the current injection, whole-cell access is spontaneously achieved within seconds from the cell-attached configuration by a self-limited membrane electroporation, or "Zap", as seal resistance increases. We present examples of intrinsic and visual responses of neurons and putative glial cells obtained with the revised method from cat and rat cortices in vivo. Recording parameters and biophysical properties obtained with the Touch and Zap method compare favourably with those obtained with the traditional blind patch approach, demonstrating that the revised approach does not compromise the recorded cell. We find that the method is particularly well-suited for whole-cell patch recordings of cortical glial cells in vivo, targeting a wider population of this cell type than the standard method, with better access resistance. Overall, the gentler Touch and Zap method is promising for studying quantitative functional properties in the intact brain with minimal perturbation of the cell's intrinsic properties and local network. Because the Touch and Zap method is performed semi-automatically, this approach is more reproducible and less dependent on experimenter technique.

The Touch and Zap Method for In Vivo Whole-Cell Patch Recording of Intrinsic and Visual Responses of Cortical Neurons and Glial Cells

PubMed Central

Schramm, Adrien E.; Marinazzo, Daniele; Gener, Thomas; Graham, Lyle J.

2014-01-01

Whole-cell patch recording is an essential tool for quantitatively establishing the biophysics of brain function, particularly in vivo. This method is of particular interest for studying the functional roles of cortical glial cells in the intact brain, which cannot be assessed with extracellular recordings. Nevertheless, a reasonable success rate remains a challenge because of stability, recording duration and electrical quality constraints, particularly for voltage clamp, dynamic clamp or conductance measurements. To address this, we describe “Touch and Zap”, an alternative method for whole-cell patch clamp recordings, with the goal of being simpler, quicker and more gentle to brain tissue than previous approaches. Under current clamp mode with a continuous train of hyperpolarizing current pulses, seal formation is initiated immediately upon cell contact, thus the “Touch”. By maintaining the current injection, whole-cell access is spontaneously achieved within seconds from the cell-attached configuration by a self-limited membrane electroporation, or “Zap”, as seal resistance increases. We present examples of intrinsic and visual responses of neurons and putative glial cells obtained with the revised method from cat and rat cortices in vivo. Recording parameters and biophysical properties obtained with the Touch and Zap method compare favourably with those obtained with the traditional blind patch approach, demonstrating that the revised approach does not compromise the recorded cell. We find that the method is particularly well-suited for whole-cell patch recordings of cortical glial cells in vivo, targeting a wider population of this cell type than the standard method, with better access resistance. Overall, the gentler Touch and Zap method is promising for studying quantitative functional properties in the intact brain with minimal perturbation of the cell's intrinsic properties and local network. Because the Touch and Zap method is performed semi-automatically, this approach is more reproducible and less dependent on experimenter technique. PMID:24875855

New head exposure system for use in human provocation studies with EEG recording during GSM900- and UMTS-like exposure.

PubMed

Schmid, Gernot; Cecil, Stefan; Goger, Christoph; Trimmel, Michael; Kuster, Niels; Molla-Djafari, Hamid

2007-12-01

A new head exposure system for double blinded human provocation studies, which requires EEG recording during exposure with GSM900- and UMTS-like signals has been developed and dosimetrically evaluated. The system uses planar patch antennas fixed at 65 mm distance from the subject's head by a special headset, which provides minimum impairment of the test subjects and ensures an almost constant position of the antennas with respect to the head, even in case of head movements. Compared to exposure concepts operating small antennas in close proximity to the head, the concept of planar antennas at a certain distance from the head produces a much more homogeneous SAR distribution in the temporal and parietal lobe of the brain. At the same time the resulting uncertainty of exposure due to variations in head size, variations of the dielectric properties of tissues and unavoidable small changes of the antenna's position with respect to the head, is reduced to the order of approximately 3 dB, which is a significant improvement to comparable head exposure systems reported in literature in the past. To avoid electromagnetic interference on the EEG recording caused by the incident RF-field an appropriate double-shielded filter circuit has been developed. Furthermore, the effect of the presence of the sintered Ag/AgCl EEG electrodes and electrode wires on the SAR distribution inside the head has been investigated and was found to be minimal if the electrode wires are arranged orthogonal to the incident electric field vector. EEG electrode arrangement parallel to the incident field vector, however, might cause drastic changes in the SAR distribution inside the head. (c) 2007 Wiley-Liss, Inc.

Intracellular recordings of action potentials by an extracellular nanoscale field-effect transistor.

PubMed

Duan, Xiaojie; Gao, Ruixuan; Xie, Ping; Cohen-Karni, Tzahi; Qing, Quan; Choe, Hwan Sung; Tian, Bozhi; Jiang, Xiaocheng; Lieber, Charles M

2011-12-18

The ability to make electrical measurements inside cells has led to many important advances in electrophysiology. The patch clamp technique, in which a glass micropipette filled with electrolyte is inserted into a cell, offers both high signal-to-noise ratio and temporal resolution. Ideally, the micropipette should be as small as possible to increase the spatial resolution and reduce the invasiveness of the measurement, but the overall performance of the technique depends on the impedance of the interface between the micropipette and the cell interior, which limits how small the micropipette can be. Techniques that involve inserting metal or carbon microelectrodes into cells are subject to similar constraints. Field-effect transistors (FETs) can also record electric potentials inside cells, and because their performance does not depend on impedance, they can be made much smaller than micropipettes and microelectrodes. Moreover, FET arrays are better suited for multiplexed measurements. Previously, we have demonstrated FET-based intracellular recording with kinked nanowire structures, but the kink configuration and device design places limits on the probe size and the potential for multiplexing. Here, we report a new approach in which a SiO2 nanotube is synthetically integrated on top of a nanoscale FET. This nanotube penetrates the cell membrane, bringing the cell cytosol into contact with the FET, which is then able to record the intracellular transmembrane potential. Simulations show that the bandwidth of this branched intracellular nanotube FET (BIT-FET) is high enough for it to record fast action potentials even when the nanotube diameter is decreased to 3 nm, a length scale well below that accessible with other methods. Studies of cardiomyocyte cells demonstrate that when phospholipid-modified BIT-FETs are brought close to cells, the nanotubes can spontaneously penetrate the cell membrane to allow the full-amplitude intracellular action potential to be recorded, thus showing that a stable and tight seal forms between the nanotube and cell membrane. We also show that multiple BIT-FETs can record multiplexed intracellular signals from both single cells and networks of cells.

Intracellular recordings of action potentials by an extracellular nanoscale field-effect transistor

NASA Astrophysics Data System (ADS)

Duan, Xiaojie; Gao, Ruixuan; Xie, Ping; Cohen-Karni, Tzahi; Qing, Quan; Choe, Hwan Sung; Tian, Bozhi; Jiang, Xiaocheng; Lieber, Charles M.

2012-03-01

The ability to make electrical measurements inside cells has led to many important advances in electrophysiology. The patch clamp technique, in which a glass micropipette filled with electrolyte is inserted into a cell, offers both high signal-to-noise ratio and temporal resolution. Ideally, the micropipette should be as small as possible to increase the spatial resolution and reduce the invasiveness of the measurement, but the overall performance of the technique depends on the impedance of the interface between the micropipette and the cell interior, which limits how small the micropipette can be. Techniques that involve inserting metal or carbon microelectrodes into cells are subject to similar constraints. Field-effect transistors (FETs) can also record electric potentials inside cells, and because their performance does not depend on impedance, they can be made much smaller than micropipettes and microelectrodes. Moreover, FET arrays are better suited for multiplexed measurements. Previously, we have demonstrated FET-based intracellular recording with kinked nanowire structures, but the kink configuration and device design places limits on the probe size and the potential for multiplexing. Here, we report a new approach in which a SiO2 nanotube is synthetically integrated on top of a nanoscale FET. This nanotube penetrates the cell membrane, bringing the cell cytosol into contact with the FET, which is then able to record the intracellular transmembrane potential. Simulations show that the bandwidth of this branched intracellular nanotube FET (BIT-FET) is high enough for it to record fast action potentials even when the nanotube diameter is decreased to 3 nm, a length scale well below that accessible with other methods. Studies of cardiomyocyte cells demonstrate that when phospholipid-modified BIT-FETs are brought close to cells, the nanotubes can spontaneously penetrate the cell membrane to allow the full-amplitude intracellular action potential to be recorded, thus showing that a stable and tight seal forms between the nanotube and cell membrane. We also show that multiple BIT-FETs can record multiplexed intracellular signals from both single cells and networks of cells.

Tonantzitlolone is a Nanomolar Potency Activator of TRPC1/4/5 Channels.

PubMed

Rubaiy, Hussein N; Ludlow, Melanie J; Siems, Karsten; Norman, Katherine; Foster, Richard; Wolf, Dietmar; Beutler, John A; Beech, David J

2018-06-02

The diterpene ester tonantzitlonone (TZL) is a natural product which displays cytotoxicity towards certain types of cancer cell such as renal cell carcinoma cells. The effect is similar to that of (-)-Englerin A (EA) and so, although it is chemically distinct, we investigated whether TZL also targets transient receptor potential canonical (TRPC) channels of the TRPC1, TRPC4 and TRPC5 type (TRPC1/4/5 channels). Renal cell carcinoma A498 cells natively expressing TRPC1 and TRPC4, modified HEK 293 cells over expressing TRPC4, TRPC5, TRPC4-TRPC1 or TRPC5-TRPC1 concatemer, TRPC3 or TRPM2 or CHO cells over expressing TRPV4 were studied by intracellular Ca 2+ measurement or whole-cell or excised membrane patch-clamp electrophysiology. TZL evoked intracellular Ca 2+ elevation in A498 cells, similar to that evoked by EA. TZL activated overexpressed channels with concentration for 50% activation (EC 50 ) at 123 nM (TRPC4), 83 nM (TRPC5), 140 nM (TRPC4-TRPC1) and 61 nM (TRPC5-TRPC1). Effects of TZL were reversible on wash-out and potently inhibited by the TRPC1/4/5 inhibitor Pico145. TZL activated TRPC5 channels when bath-applied to excised outside-out but not inside-out patches. TZL failed to activate endogenous store-operated Ca 2+ entry in HEK 293 cells or overexpressed TRPC3, TRPV4 or TRPM2 channels. TZL is a novel potent agonist for TRPC1/4/5 channels which should be useful for testing the functionality of this type of ion channel and understanding how TRPC1/4/5 agonists achieve selective cytotoxicity against certain types of cancer cell. This article is protected by copyright. All rights reserved.

Sperm Patch-Clamp

PubMed Central

Lishko, Polina; Clapham, David E.; Navarro, Betsy; Kirichok, Yuriy

2014-01-01

Sperm intracellular pH and calcium concentration ([Ca2+]i) are two central factors that control sperm activity within the female reproductive tract. As such, the ion channels of the sperm plasma membrane that alter intracellular sperm [Ca2+] and pH play important roles in sperm physiology and the process of fertilization. Indeed, sperm ion channels regulate sperm motility, control sperm chemotaxis toward the egg in some species, and may trigger the acrosome reaction. Until recently, our understanding of these important molecules was rudimentary due to the inability to patch-clamp spermatozoa and directly record the activity of these ion channels under voltage clamp. Recently, we overcame this technical barrier and developed a method for reproducible application of the patch-clamp technique to mouse and human spermatozoa. This chapter covers important aspects of application of the patch-clamp technique to spermatozoa, such as selection of the electrophysiological equipment, isolation of spermatozoa for patch-clamp experiments, formation of the gigaohm seal with spermatozoa, and transition into the whole-cell mode of recording. We also discuss potential pitfalls in application of the patch-clamp technique to flagellar ion channels. PMID:23522465

LabPatch, an acquisition and analysis program for patch-clamp electrophysiology.

PubMed

Robinson, T; Thomsen, L; Huizinga, J D

2000-05-01

An acquisition and analysis program, "LabPatch," has been developed for use in patch-clamp research. LabPatch controls any patch-clamp amplifier, acquires and records data, runs voltage protocols, plots and analyzes data, and connects to spreadsheet and database programs. Controls within LabPatch are grouped by function on one screen, much like an oscilloscope front panel. The software is mouse driven, so that the user need only point and click. Finally, the ability to copy data to other programs running in Windows 95/98, and the ability to keep track of experiments using a database, make LabPatch extremely versatile. The system requirements include Windows 95/98, at least a 100-MHz processor and 16 MB RAM, a data acquisition card, digital-to-analog converter, and a patch-clamp amplifier. LabPatch is available free of charge at http://www.fhs.mcmaster.ca/huizinga/.

Inside Victoria Crater for Extended Exploration

NASA Technical Reports Server (NTRS)

2007-01-01

After a finishing an in-and-out maneuver to check wheel slippage near the rim of Victoria Crater, NASA's Mars Exploration Rover Opportunity re-entered the crater during the rover's 1,293rd Martian day, or sol, (Sept. 13, 2007) to begin a weeks-long exploration of the inner slope.

Opportunity's front hazard-identification camera recorded this wide-angle view looking down into and across the crater at the end of the day's drive. The rover's position was about six meters (20 feet) inside the rim, in the 'Duck Bay' alcove of the crater.

Outside-out "sniffer-patch" clamp technique for in situ measures of neurotransmitter release.

PubMed

Muller-Chrétien, Emilie

2014-01-01

The mechanism underlying neurotransmitter release is a critical research domain for the understanding of neuronal network function; however, few techniques are available for the direct detection and measurement of neurotransmitter release. To date, the sniffer-patch clamp technique is mainly used to investigate these mechanisms from individual cultured cells. In this study, we propose to adapt the sniffer-patch clamp technique to in situ detection of neurosecretion. Using outside-out patches from donor cells as specific biosensors plunged in acute cerebral slices, this technique allows for proper detection and quantification of neurotransmitter release at the level of the neuronal network.

Patching. Restitching business portfolios in dynamic markets.

PubMed

Eisenhardt, K M; Brown, S L

1999-01-01

In turbulent markets, businesses and opportunities are constantly falling out of alignment. New technologies and emerging markets create fresh opportunities. Converging markets produce more. And of course, some markets fade. In this landscape of continuous flux, it's more important to build corporate-level strategic processes that enable dynamic repositioning than it is to build any particular defensible position. That's why smart corporate strategists use patching, a process of mapping and remapping business units to create a shifting mix of highly focused, tightly aligned businesses that can respond to changing market opportunities. Patching is not just another name for reorganizing; patchers have a distinctive mindset. Traditional managers see structure as stable; patching managers believe structure is inherently temporary. Traditional managers set corporate strategy first, but patching managers keep the organization focused on the right set of business opportunities and let strategy emerge from individual businesses. Although the focus of patching is flexibility, the process itself follows a pattern. Patching changes are usually small in scale and made frequently. Patching should be done quickly; the emphasis is on getting the patch about right and fixing problems later. Patches should have a test drive before they're formalized but then be tightly scripted after they've been announced. And patching won't work without the right infrastructure: modular business units, fine-grained and complete unit-level metrics, and companywide compensation parity. The authors illustrate how patching works and point out some common stumbling blocks.

The hSK4 (KCNN4) isoform is the Ca2+-activated K+ channel (Gardos channel) in human red blood cells

PubMed Central

Hoffman, Joseph F.; Joiner, William; Nehrke, Keith; Potapova, Olga; Foye, Kristen; Wickrema, Amittha

2003-01-01

The question is, does the isoform hSK4, also designated KCNN4, represent the small conductance, Ca2+-activated K+ channel (Gardos channel) in human red blood cells? We have analyzed human reticulocyte RNA by RT-PCR, and, of the four isoforms of SK channels known, only SK4 was found. Northern blot analysis of purified and synchronously growing human erythroid progenitor cells, differentiating from erythroblasts to reticulocytes, again showed only the presence of SK4. Western blot analysis, with an anti-SK4 antibody, showed that human erythroid progenitor cells and, importantly, mature human red blood cell ghost membranes, both expressed the SK4 protein. The Gardos channel is known to turn on, given inside Ca2+, in the presence but not the absence of external \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}{\\mathrm{K}}_{{\\mathrm{o}}}^{+}\\end{equation*}\\end{document} and remains refractory to \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} \\begin{equation*}{\\mathrm{K}}_{{\\mathrm{o}}}^{+}\\end{equation*}\\end{document} added after exposure to inside Ca2+. Heterologously expressed SK4, but not SK3, also shows this behavior. In inside–out patches of red cell membranes, the open probability (Po) of the Gardos channel is markedly reduced when the temperature is raised from 27 to 37°C. Net K+ efflux of intact red cells is also reduced by increasing temperature, as are the Po values of inside–out patches of Chinese hamster ovary cells expressing SK4 (but not SK3). Thus the envelope of evidence indicates that SK4 is the gene that codes for the Gardos channel in human red blood cells. This channel is important pathophysiologically, because it represents the major pathway for cell shrinkage via KCl and water loss that occurs in sickle cell disease. PMID:12773623

Modulation of K(Ca)3.1 channels by eicosanoids, omega-3 fatty acids, and molecular determinants.

PubMed

Kacik, Michael; Oliván-Viguera, Aida; Köhler, Ralf

2014-01-01

Cytochrome P450- and ω-hydrolase products (epoxyeicosatrienoic acids (EETs), hydroxyeicosatetraeonic acid (20-HETE)), natural omega-3 fatty acids (ω3), and pentacyclic triterpenes have been proposed to contribute to a wide range of vaso-protective and anti-fibrotic/anti-cancer signaling pathways including the modulation of membrane ion channels. Here we studied the modulation of intermediate-conductance Ca(2+)/calmodulin-regulated K(+) channels (K(Ca)3.1) by EETs, 20-HETE, ω3, and pentacyclic triterpenes and the structural requirements of these fatty acids to exert channel blockade. We studied modulation of cloned human hK(Ca)3.1 and the mutant hK(Ca)3.1(V275A) in HEK-293 cells, of rK(Ca)3.1 in aortic endothelial cells, and of mK(Ca)3.1 in 3T3-fibroblasts by inside-out and whole-cell patch-clamp experiments, respectively. In inside-out patches, Ca(2+)-activated hK(Ca)3.1 were inhibited by the ω3, DHA and α-LA, and the ω6, AA, in the lower µmolar range and with similar potencies. 5,6-EET, 8,9-EET, 5,6-DiHETE, and saturated arachidic acid, had no appreciable effects. In contrast, 14,15-EET, its stable derivative, 14,15-EEZE, and 20-HETE produced channel inhibition. 11,12-EET displayed less inhibitory activity. The K(Ca)3.1(V275A) mutant channel was insensitive to any of the blocking EETs. Non-blocking 5,6-EET antagonized the inhibition caused by AA and augmented cloned hK(Ca)3.1 and rK(Ca)3.1 whole-cell currents. Pentacyclic triterpenes did not modulate K(Ca)3.1 currents. Inhibition of K(Ca)3.1 by EETs (14,15-EET), 20-HETE, and ω3 critically depended on the presence of electron double bonds and hydrophobicity within the 10 carbons preceding the carboxyl-head of the molecules. From the physiological perspective, metabolism of AA to non-blocking 5,6,- and 8,9-EET may cause AA-de-blockade and contribute to cellular signal transduction processes influenced by these fatty acids.

Reconstruction dynamics of recorded holograms in photochromic glass.

PubMed

Mihailescu, Mona; Pavel, Eugen; Nicolae, Vasile B

2011-06-20

We have investigated the dynamics of the record-erase process of holograms in photochromic glass using continuum Nd:YVO₄ laser radiation (λ=532 nm). A bidimensional microgrid pattern was formed and visualized in photochromic glass, and its diffraction efficiency decay versus time (during reconstruction step) gave us information (D, Δn) about the diffusion process inside the material. The recording and reconstruction processes were carried out in an off-axis setup, and the images of the reconstructed object were recorded by a CCD camera. Measurements realized on reconstructed object images using holograms recorded at a different incident power laser have shown a two-stage process involved in silver atom kinetics.

Electric field distribution on surface of the artificial magnetic conductor: miniaturization process

NASA Astrophysics Data System (ADS)

Ramos, Welyson T. S.; Mesquita, Renato C.; Silva, Elson J.

2017-08-01

This paper presents a study of the influence of the geometric shape on the resonance frequency of the artificial magnetic conductor (AMC) by analysis of the electric field distributions on top of the surface metallic patch inside the unit cell. It is known that various parameters such as geometry, dielectric substrate thickness, gap between patches, length and width of patch, size of unit cell, permittivity and permeability strongly affect the resonance frequency. In attempts to elucidate the miniaturization process, as reference, a metallic square patch with a unit cell of size 10 mm × 10 mm was simulated and a resonance frequency of 5.75 GHz was obtained. The device has illuminated by a plane wave with polarization in the y direction. Additionally, different geometries were performed such as triangle, hexagon, circle and cross of Jerusalem. We realized that the field distribution can be used as an physical insight to understand the AMC miniaturization process. In particular, bow-tie geometry provided considerable electrical miniaturization compared with square patch, about 1.5 GHz. The results are supported by finite element method. Our findings suggest that shift at resonant frequency may be interpreted as a variation in the net induced electric polarizability on the surface of the metallic patches.

The Role of Small Woodland Remnants on Ground Dwelling Insect Conservation in Chaco Serrano, Central Argentina

PubMed Central

Moreno, María Laura; Fernández, María Guadalupe; Molina, Silvia Itati; Valladares, Graciela

2013-01-01

Many terrestrial ecosystems are changing due to extensive land use and habitat fragmentation, posing a major threat to biodiversity. In this study, the effects of patch size, isolation, and edge/interior localization on the ground dwelling insect communities in the Chaco Serrano woodland remnants in central Argentina were examined. Sampling was carried out in December 2003 and March 2004 in nine remnants (0.57 to 1000 hectares) using pitfall traps. In total, 7071 individuals representing 12 orders and 79 families were recorded. The taxonomic composition of these communities was linked to remnant size. Insect abundance increased (as did their richness, albeit marginally) as remnant area decreased, with no significant effects of isolation or edge/interior localization on abundance, richness, or diversity. No differential area effects were observed when abundance and richness of predators, scavengers, and herbivores were compared. Thus, ground insect communities in fragmented Chaco Serrano seem to respond mainly to patch level, rather than to within-patch (edge effects) or landscape (isolation) level variables. These results suggest that small Chaco Serrano remnants, by supporting larger ground-dwelling insect assemblages, may play an important role from a conservation viewpoint. PMID:23902409

The role of small woodland remnants on ground dwelling insect conservation in Chaco Serrano, Central Argentina.

PubMed

Moreno, María Laura; Fernández, María Guadalupe; Molina, Silvia Itati; Valladares, Graciela

2013-01-01

Many terrestrial ecosystems are changing due to extensive land use and habitat fragmentation, posing a major threat to biodiversity. In this study, the effects of patch size, isolation, and edge/interior localization on the ground dwelling insect communities in the Chaco Serrano woodland remnants in central Argentina were examined. Sampling was carried out in December 2003 and March 2004 in nine remnants (0.57 to 1000 hectares) using pitfall traps. In total, 7071 individuals representing 12 orders and 79 families were recorded. The taxonomic composition of these communities was linked to remnant size. Insect abundance increased (as did their richness, albeit marginally) as remnant area decreased, with no significant effects of isolation or edge/interior localization on abundance, richness, or diversity. No differential area effects were observed when abundance and richness of predators, scavengers, and herbivores were compared. Thus, ground insect communities in fragmented Chaco Serrano seem to respond mainly to patch level, rather than to within-patch (edge effects) or landscape (isolation) level variables. These results suggest that small Chaco Serrano remnants, by supporting larger ground-dwelling insect assemblages, may play an important role from a conservation viewpoint.

The Nano-Patch-Clamp Array: Microfabricated Glass Chips for High-Throughput Electrophysiology

NASA Astrophysics Data System (ADS)

Fertig, Niels

2003-03-01

Electrophysiology (i.e. patch clamping) remains the gold standard for pharmacological testing of putative ion channel active drugs (ICADs), but suffers from low throughput. A new ion channel screening technology based on microfabricated glass chip devices will be presented. The glass chips contain very fine apertures, which are used for whole-cell voltage clamp recordings as well as single channel recordings from mammalian cell lines. Chips containing multiple patch clamp wells will be used in a first bench-top device, which will allow perfusion and electrical readout of each well. This scalable technology will allow for automated, rapid and parallel screening on ion channel drug targets.

Collisions of Ir Oxide Nanoparticles with Carbon Nanopipettes: Experiments with One Nanoparticle.

PubMed

Zhou, Min; Yu, Yun; Hu, Keke; Xin, Huolin L; Mirkin, Michael V

2017-03-07

Investigating the collisions of individual metal nanoparticles (NPs) with electrodes can provide new insights into their electrocatalytic behavior, mass transport, and interactions with surfaces. Here we report a new experimental setup for studying NP collisions based on the use of carbon nanopipettes to enable monitoring multiple collision events involving the same NP captured inside the pipet cavity. A patch clamp amplifier capable of measuring pA-range currents on the microsecond time scale with a very low noise and stable background was used to record the collision transients. The analysis of current transients produced by oxidation of hydrogen peroxide at one IrO x NP provided information about the origins of deactivation of catalytic NPs and the effects of various experimental conditions on the collision dynamics. High-resolution TEM of carbon pipettes was used to attain better understanding of the NP capture and collisions.

Collisions of Ir oxide nanoparticles with carbon nanopipettes: Experiments with one nanoparticle

DOE PAGES

Zhou, Min; Yu, Yun; Hu, Keke; ...

2017-02-03

Investigating the collisions of individual metal nanoparticles (NPs) with electrodes can provide new insights into their electrocatalytic behavior, mass transport, and interactions with surfaces. Here we report a new experimental setup for studying NP collisions based on the use of carbon nanopipettes to enable monitoring multiple collision events involving the same NP captured inside the pipet cavity. A patch clamp amplifier capable of measuring pA-range currents on the microsecond time scale with a very low noise and stable background was used to record the collision transients. The analysis of current transients produced by oxidation of hydrogen peroxide at one IrOxmore » NP provided information about the origins of deactivation of catalytic NPs and the effects of various experimental conditions on the collision dynamics. Lastly, high-resolution TEM of carbon pipettes was used to attain better understanding of the NP capture and collisions.« less

Using hyperspectral plant signatures for CO2 leak detection during the 2008 ZERT CO2 sequestration field experiment in Bozeman, Montana

DOE Office of Scientific and Technical Information (OSTI.GOV)

Male, E.J.; Pickles, W.L.; Silver, E.A.

2009-11-01

Hyperspectral plant signatures can be used as a short-term, as well as long-term (100-yr timescale) monitoring technique to verify that CO2 sequestration fields have not been compromised. An influx of CO2 gas into the soil can stress vegetation, which causes changes in the visible to nearinfrared reflectance spectral signature of the vegetation. For 29 days, beginning on July 9th, 2008, pure carbon dioxide gas was released through a 100-meter long horizontal injection well, at a flow rate of 300 kg/day. Spectral signatures were recorded almost daily from an unmown patch of plants over the injection with a ''FieldSpec Pro'' spectrometermore » by Analytical Spectral Devices, Inc. Measurements were taken both inside and outside of the CO2 leak zone to normalize observations for other environmental factors affecting the plants.« less

Dynamics of T-Junction Solution Switching Aimed at Patch Clamp Experiments

PubMed Central

Auzmendi, Jerónimo A.; Smoler, Mariano; Moffatt, Luciano

2015-01-01

Solutions exchange systems are responsible for the timing of drug application on patch clamp experiments. There are two basic strategies for generating a solution exchange. When slow exchanges are bearable, it is easier to perform the exchange inside the tubing system upstream of the exit port. On the other hand, fast, reproducible, exchanges are usually performed downstream of the exit port. As both strategies are combinable, increasing the performance of upstream exchanges is desirable. We designed a simple method for manufacturing T-junctions (300 μm I.D.) and we measured the time profile of exchange of two saline solutions using a patch pipette with an open tip. Three factors were found to determine the timing of the solution switching: pressure, travelled distance and off-center distance. A linear relationship between the time delay and the travelled distance was found for each tested pressure, showing its dependence to the fluid velocity, which increased with pressure. The exchange time was found to increase quadratically with the delay, although a sizeable variability remains unexplained by this relationship. The delay and exchange times increased as the recording pipette moved away from the center of the stream. Those increases became dramatic as the pipette was moved close to the stream borders. Mass transport along the travelled distance between the slow fluid at the border and the fast fluid at the center seems to contribute to the time course of the solution exchange. This effect would be present in all tubing based devices. Present results might be of fundamental importance for the adequate design of serial compound exchangers which would be instrumental in the discovery of drugs that modulate the action of the physiological agonists of ion channels with the purpose of fine tuning their physiology. PMID:26177538

Carbon Explorer Assessment of Carbon Biomass Variability and Carbon Flux Systematics in the Upper Ocean During SOFEX

NASA Astrophysics Data System (ADS)

Bishop, J. K.; Wood, T. J.; Sherman, J. T.

2002-12-01

Three autonomous Carbon Explorers built on SIO's Orbcomm/GPS enhanced Sounding Oceanographic Lagrangian Observer were launched near 55S 172W in the "North" SOFEX experiment area in early January 2002. All Explorers at 55S were programmed to perform profiles from 1000, 300, and 300 m with surfacings, GPS position, and telemetry of profile data initiating at local 0600, 1200, and 1800 hours. The floats were programmed to 'sleep' at 100 m depth between profiles to maximize tracking of the surface layer. Each Explorer carried SeaBird T and S sensors and was additionally fitted with a WETLabs transmissometer based "POC" sensor and a Seapoint scattering meter to assess particulate matter variability. A carbon flux "index" obtained during the 100 m sleep periods was also derived from the POC sensor readings. Explorer 1177 was deployed as a control outside of Fe treated waters on Jan 11 2002 (UTC) and drifted initially to the North East at 10 cm/sec. Explorer 2104, deployed on Jan 19 2002 after the 3rd Fe infusion, advected with the patch to the NE on a course that closely paralleled that of the "control". By Feb 8 2002, the two floats had drifted with the circumpolar current nearly 200 km; Explorer 2104 had recorded a 4-fold build-up of of particles in the upper 60 m whereas records from the nearby control Explorer 1177 showed little change. Ship survey data (Revelle) indicated that Explorer 2104 was near but "in" the trailing edge of the patch. Beginning Feb 14 (several days after the 4th infusion of Fe) and ending on Feb 24 2002, Explorer 2104 data showed isolines of POC concentration beginning to deepen in waters below 60 m and a coincident loss of POC from above; the POC flux index also began to show clearly different and enhanced 'spikes' compared to that recorded by the control. The spikes either reflected temporal variability of particle export from the patch or the intermingled sampling of the "in patch" settling plume of particles and "out-of-patch" background flux. Preliminary analysis of POC flux index integrated over time since the initial Fe amendment indicated a >2 fold enhancement of export from the iron treated waters. If the Explorer was indeed sampling the plume of sinking material intermittently, then the true export enhancement from the patch would be considerably greater. The last 'trace' of Fe treated waters was seen in early March 2002. Explorers 1177 and 2104 continue operations in the howling 50's of the Southern Ocean 8+ months after their deployment.

Digital PCR to determine the number of transcripts from single neurons after patch-clamp recording.

PubMed

Faragó, Nóra; Kocsis, Ágnes K; Lovas, Sándor; Molnár, Gábor; Boldog, Eszter; Rózsa, Márton; Szemenyei, Viktor; Vámos, Enikő; Nagy, Lajos I; Tamás, Gábor; Puskás, László G

2013-06-01

Whole-cell patch-clamp recording enables detection of electrophysiological signals from single neurons as well as harvesting of perisomatic RNA through the patch pipette for subsequent gene expression analysis. Amplification and profiling of RNA with traditional quantitative real-time PCR (qRT-PCR) do not provide exact quantitation due to experimental variation caused by the limited amount of nucleic acid in a single cell. Here we describe a protocol for quantifying mRNA or miRNA expression in individual neurons after patch-clamp recording using high-density nanocapillary digital PCR (dPCR). Expression of a known cell-type dependent marker gene (gabrd), as well as oxidative-stress related induction of hspb1 and hmox1 expression, was quantified in individual neurogliaform and pyramidal cells, respectively. The miRNA mir-132, which plays a role in neurodevelopment, was found to be equally expressed in three different types of neurons. The accuracy and sensitivity of this method were further validated using synthetic spike-in templates and by detecting genes with very low levels of expression.

Dynamic Source Inversion of a M6.5 Intraslab Earthquake in Mexico: Application of a New Parallel Genetic Algorithm

NASA Astrophysics Data System (ADS)

Díaz-Mojica, J. J.; Cruz-Atienza, V. M.; Madariaga, R.; Singh, S. K.; Iglesias, A.

2013-05-01

We introduce a novel approach for imaging the earthquakes dynamics from ground motion records based on a parallel genetic algorithm (GA). The method follows the elliptical dynamic-rupture-patch approach introduced by Di Carli et al. (2010) and has been carefully verified through different numerical tests (Díaz-Mojica et al., 2012). Apart from the five model parameters defining the patch geometry, our dynamic source description has four more parameters: the stress drop inside the nucleation and the elliptical patches; and two friction parameters, the slip weakening distance and the change of the friction coefficient. These parameters are constant within the rupture surface. The forward dynamic source problem, involved in the GA inverse method, uses a highly accurate computational solver for the problem, namely the staggered-grid split-node. The synthetic inversion presented here shows that the source model parameterization is suitable for the GA, and that short-scale source dynamic features are well resolved in spite of low-pass filtering of the data for periods comparable to the source duration. Since there is always uncertainty in the propagation medium as well as in the source location and the focal mechanisms, we have introduced a statistical approach to generate a set of solution models so that the envelope of the corresponding synthetic waveforms explains as much as possible the observed data. We applied the method to the 2012 Mw6.5 intraslab Zumpango, Mexico earthquake and determined several fundamental source parameters that are in accordance with different and completely independent estimates for Mexican and worldwide earthquakes. Our weighted-average final model satisfactorily explains eastward rupture directivity observed in the recorded data. Some parameters found for the Zumpango earthquake are: Δτ = 30.2+/-6.2 MPa, Er = 0.68+/-0.36x10^15 J, G = 1.74+/-0.44x10^15 J, η = 0.27+/-0.11, Vr/Vs = 0.52+/-0.09 and Mw = 6.64+/-0.07; for the stress drop, radiated energy, fracture energy, radiation efficiency, rupture velocity and moment magnitude, respectively. Mw6.5 intraslab Zumpango earthquake location, stations location and tectonic setting in central Mexico

Cross-talk between ATP-regulated K+ channels and Na+ transport via cellular metabolism in frog skin principal cells.

PubMed Central

Urbach, V; Van Kerkhove, E; Maguire, D; Harvey, B J

1996-01-01

Isolated frog skin epithelium, mounted in an Ussing chamber and bathed in standard NaCl Ringer solution, recycles K+ across the basolateral membrane of principal cells through an inward-rectifier K+ channel (Kir) operating in parallel with a Na+-K+-ATPase pump. Here we report on the metabolic control of the Kir channel using patch clamping, short-circuit current measurement and enzymatic determination of cellular (ATP (ATPi). 2. The constitutively active Kir channel in the basolateral membrane has the characteristics of an ATP-regulated K+ channel and is now classed as a KATP channel. In excised inside-out patches the open probability (Po) of KATP channels was reduced by ATPi with half-maximum inhibition at an ATPi concentration of 50 microM. 3. ATPi measured (under normal Na+ transport conditions) with luciferin-luciferase was 1.50 +/- 0.23 mM (mean +/- S.E.M.; range, 0.4-3.3 mM n = 11). Thus the KATP channel would be expected to be inactive in intact cells if ATPi was the sole regulator of channel activity. KATP channels which were inactivated by 1 mM ATPi in excised patches could be reactivated by addition of 100 microM ADP on the cytosolic side. When added alone, ADP blocks this channel with half-maximal inhibition at [ADPi] > 5 mM. 4. Sulphonylureas inhibit single KATP channels in cell-attached patches as well as the total basolateral K+ current measured in frog skin epithelia perforated with nystatin on the apical side. 5. Na+-K+-ATPase activity is a major determinant of cytosolic ATP. Blocking the pump activity with ouabain produced a time-dependent increase in ATPi and reduced the open probability of KATP channels in cell-attached membranes. 6. We conclude that the ratio of ATP/ADP is an important metabolic coupling factor between the rate of Na+-K+ pumping and K+ recycling. Images Figure 9 PMID:9011625

Activation of the Ano1 (TMEM16A) chloride channel by calcium is not mediated by calmodulin

PubMed Central

Zhu, Jinqiu; Qu, Zhiqiang; Cui, Yuan-Yuan; Hartzell, H. Criss

2014-01-01

The Ca2+-activated Cl channel anoctamin-1 (Ano1; Tmem16A) plays a variety of physiological roles, including epithelial fluid secretion. Ano1 is activated by increases in intracellular Ca2+, but there is uncertainty whether Ca2+ binds directly to Ano1 or whether phosphorylation or additional Ca2+-binding subunits like calmodulin (CaM) are required. Here we show that CaM is not necessary for activation of Ano1 by Ca2+ for the following reasons. (a) Exogenous CaM has no effect on Ano1 currents in inside-out excised patches. (b) Overexpression of Ca2+-insensitive mutants of CaM have no effect on Ano1 currents, whereas they eliminate the current mediated by the small-conductance Ca2+-activated K+ (SK2) channel. (c) Ano1 does not coimmunoprecipitate with CaM, whereas SK2 does. Furthermore, Ano1 binds very weakly to CaM in pull-down assays. (d) Ano1 is activated in excised patches by low concentrations of Ba2+, which does not activate CaM. In addition, we conclude that reversible phosphorylation/dephosphorylation is not required for current activation by Ca2+ because the current can be repeatedly activated in excised patches in the absence of ATP or other high-energy compounds. Although Ano1 is blocked by the CaM inhibitor trifluoperazine (TFP), we propose that TFP inhibits the channel in a CaM-independent manner because TFP does not inhibit Ano1 when applied to the cytoplasmic side of excised patches. These experiments lead us to conclude that CaM is not required for activation of Ano1 by Ca2+. Although CaM is not required for channel opening by Ca2+, work of other investigators suggests that CaM may have effects in modulating the biophysical properties of the channel. PMID:24420770

Volume-dependent ATP-conductive large-conductance anion channel as a pathway for swelling-induced ATP release.

PubMed

Sabirov, R Z; Dutta, A K; Okada, Y

2001-09-01

In mouse mammary C127i cells, during whole-cell clamp, osmotic cell swelling activated an anion channel current, when the phloretin-sensitive, volume-activated outwardly rectifying Cl(-) channel was eliminated. This current exhibited time-dependent inactivation at positive and negative voltages greater than around +/-25 mV. The whole-cell current was selective for anions and sensitive to Gd(3)+. In on-cell patches, single-channel events appeared with a lag period of approximately 15 min after a hypotonic challenge. Under isotonic conditions, cell-attached patches were silent, but patch excision led to activation of currents that consisted of multiple large-conductance unitary steps. The current displayed voltage- and time-dependent inactivation similar to that of whole-cell current. Voltage-dependent activation profile was bell-shaped with the maximum open probability at -20 to 0 mV. The channel in inside-out patches had the unitary conductance of approximately 400 pS, a linear current-voltage relationship, and anion selectivity. The outward (but not inward) single-channel conductance was suppressed by extracellular ATP with an IC(50) of 12.3 mM and an electric distance (delta) of 0.47, whereas the inward (but not outward) conductance was inhibited by intracellular ATP with an IC(50) of 12.9 mM and delta of 0.40. Despite the open channel block by ATP, the channel was ATP-conductive with P(ATP)/P(Cl) of 0.09. The single-channel activity was sensitive to Gd(3)+, SITS, and NPPB, but insensitive to phloretin, niflumic acid, and glibenclamide. The same pharmacological pattern was found in swelling-induced ATP release. Thus, it is concluded that the volume- and voltage-dependent ATP-conductive large-conductance anion channel serves as a conductive pathway for the swelling-induced ATP release in C127i cells.

Mating success of males with and without wing patch in Drosophila biarmipes.

PubMed

Hegde, S N; Chethan, B K; Krishna, M S

2005-10-01

Some males of D. biarmipes--synonym of D. rajasekari and D. raychaudhuri have a black patch on the wing. The patch extends from the apical margin of wing to the third longitudinal vein. Field and laboratory studies have been carried out in D. biarmipes to study role of male's wing patch in mating success. The field study shows that nature favors D. biarmipes males with patch. Although males without patch mated, males with patch have higher mating success suggesting the role of wing patch during courtship. Further, among mating males, males with patch had longer wings than males without patch. During courtship, males with patch oriented and mated faster; performed courtship acts such as tapping, scissoring, vibration, licking and twist dance more times than males without patch in both competitive and non-competitive situations. The results indicate that there is a casual relationship between the presence of wing patch, mating speed and success. Also there is a correlation between presence of wing patch, size of the flies and mating success.

Automated navigation of a glass micropipette on a high-density microelectrode array.

PubMed

Jing Lin; Obien, Marie Engelene J; Hierlemann, Andreas; Frey, Urs

2015-08-01

High-density microelectrode arrays (HDMEAs) provide the capability to monitor the extracellular electric potential of multiple neurons at subcellular resolution over extended periods of time. In contrast, patch clamp allows for intracellular, sub-threshold recordings from a single patched neuron for very limited time on the order of an hour. Therefore, it will be beneficial to combine HDMEA and patch clamp for simultaneous intra- and extracellular recording of neuronal activity. Previously, it has been shown that the HDMEA can be used to localize and steer a glass micropipette towards a target location without using an optical microscope [1]. Here, we present an automated system, implemented in LabVIEW, which automatically locates and moves the glass micropipette towards a user-defined target. The presented system constitutes a first step towards developing an automated system to navigate a pipette to patch a neuron in vitro.

Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function

PubMed Central

Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

2016-01-01

In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, free-standing electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on-demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function. PMID:26974408

Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function.

PubMed

Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

2016-06-01

In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, freestanding electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function.

Landscape connectivity promotes plant biodiversity spillover into non-target habitats.

PubMed

Brudvig, Lars A; Damschen, Ellen I; Tewksbury, Joshua J; Haddad, Nick M; Levey, Douglas J

2009-06-09

Conservation efforts typically focus on maximizing biodiversity in protected areas. The space available for reserves is limited, however, and conservation efforts must increasingly consider how management of protected areas can promote biodiversity beyond reserve borders. Habitat corridors are considered an important feature of reserves because they facilitate movement of organisms between patches, thereby increasing species richness in those patches. Here we demonstrate that by increasing species richness inside target patches, corridors additionally benefit biodiversity in surrounding non-target habitat, a biodiversity "spillover" effect. Working in the world's largest corridor experiment, we show that increased richness extends for approximately 30% of the width of the 1-ha connected patches, resulting in 10-18% more vascular plant species around patches of target habitat connected by corridors than around unconnected but otherwise equivalent patches of habitat. Furthermore, corridor-enhanced spillover into non-target habitat can be predicted by a simple plant life-history trait: seed dispersal mode. Species richness of animal-dispersed plants in non-target habitat increased in response to connectivity provided by corridors, whereas species richness of wind-dispersed plants was unaffected by connectivity and increased in response to changes in patch shape--higher edge-to-interior ratio--created by corridors. Corridors promoted biodiversity spillover for native species of the threatened longleaf pine ecosystem being restored in our experiment, but not for exotic species. By extending economically driven spillover concepts from marine fisheries and crop pollination systems, we show how reconnecting landscapes amplifies biodiversity conservation both within and beyond reserve borders.

FOOT ECZEMA: THE ROLE OF PATCH TEST IN DETERMINING THE CAUSATIVE AGENT USING STANDARD SERIES

PubMed Central

Priya, K S; Kamath, Ganesh; Martis, Jacintha; D, Sukumar; Shetty, Narendra J; Bhat, Ramesh M; Kishore, B Nanda

2008-01-01

Foot dermatitis refers to the predominant involvement of feet in the eczematous process. This study is undertaken to determine the clinical pattern and causative agent in foot eczema and to evaluate the role of patch testing in determining the causative agent of foot eczema. Data was collected from 50 patients with foot eczema, who attended the out-patient department. The patch test was performed using Indian standard series. Patch test was positive in 88% of the patients. The most common site affected was the dorsal aspect of the foot (48%) and scaly plaque was the predominant morphological pattern. The highest number of patients (24%) showed positive reactions to mercaptobenzothiazole (MBT) and the lowest (4%) to neomycin sulfate. Rubber and rubber chemicals have been reported worldwide to be the most common sensitizer causing foot eczema. Thus, patch test has a major role in finding out the cause of foot eczema. PMID:19881990

Round-Horizon Version of Curiosity Low-Angle Selfie at Buckskin

NASA Image and Video Library

2015-08-19

This version of a self-portrait of NASA's Curiosity Mars rover at a drilling site called "Buckskin" on lower Mount Sharp is presented as a stereographic projection, which shows the horizon as a circle. It is a mosaic assembled from the same set of 92 component raw images used for the flatter-horizon version at PIA19807. The component images were taken by Curiosity's Mars Hand Lens Imager (MAHLI) on Aug. 5, 2015, during the 1,065th Martian day, or sol, of the rover's work on Mars. Curiosity drilled the hole at Buckskin during Sol 1060 (July 30, 2015). Two patches of pale, powdered rock material pulled from inside Buckskin are visible in this scene, in front of the rover. The patch closer to the rover is where the sample-handling mechanism on Curiosity's robotic arm dumped collected material that did not pass through a sieve in the mechanism. Sieved sample material was delivered to laboratory instruments inside the rover. The patch farther in front of the rover, roughly triangular in shape, shows where fresh tailings spread downhill from the drilling process. The drilled hole, 0.63 inch (1.6 centimeters) in diameter, is at the upper point of the tailings. The rover is facing northeast, looking out over the plains from the crest of a 20-foot (6-meter) hill that it climbed to reach the "Marias Pass" area. The upper levels of Mount Sharp are visible behind the rover, while Gale Crater's northern rim dominates most of the rest of the horizon.the horizon on the left and right of the mosaic. MAHLI is mounted at the end of the rover's robotic arm. For this self-portrait, the rover team positioned the camera lower in relation to the rover body than for any previous full self-portrait of Curiosity. The assembled mosaic does not include the rover's arm beyond a portion of the upper arm held nearly vertical from the shoulder joint. Shadows from the rest of the arm and the turret of tools at the end of the arm are visible on the ground. With the wrist motions and turret rotations used in pointing the camera for the component images, the arm was positioned out of the shot in the frames or portions of frames used in this mosaic. MAHLI was built by Malin Space Science Systems, San Diego. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Science Laboratory Project for the NASA Science Mission Directorate, Washington. JPL designed and built the project's Curiosity rover. http://photojournal.jpl.nasa.gov/catalog/PIA19806

Transdermal patches: history, development and pharmacology

PubMed Central

Pastore, Michael N; Kalia, Yogeshvar N; Horstmann, Michael; Roberts, Michael S

2015-01-01

Transdermal patches are now widely used as cosmetic, topical and transdermal delivery systems. These patches represent a key outcome from the growth in skin science, technology and expertise developed through trial and error, clinical observation and evidence-based studies that date back to the first existing human records. This review begins with the earliest topical therapies and traces topical delivery to the present-day transdermal patches, describing along the way the initial trials, devices and drug delivery systems that underpin current transdermal patches and their actives. This is followed by consideration of the evolution in the various patch designs and their limitations as well as requirements for actives to be used for transdermal delivery. The properties of and issues associated with the use of currently marketed products, such as variability, safety and regulatory aspects, are then described. The review concludes by examining future prospects for transdermal patches and drug delivery systems, such as the combination of active delivery systems with patches, minimally invasive microneedle patches and cutaneous solutions, including metered-dose systems. PMID:25560046

The permeability of the cGMP-activated channel to organic cations in retinal rods of the tiger salamander.

PubMed Central

Picco, C; Menini, A

1993-01-01

1. The permeability of the channel activated by guanosine 3',5'-cyclic monophosphate (cGMP) to many organic monovalent cations was determined by recording macroscopic currents in excised inside-out patches of plasma membrane from isolated retinal rod outer segments of the tiger salamander. 2. Current-voltage relations were measured when the NaCl of the bathing medium was replaced by salts of organic cations. Permeability ratios relative to Na+ ions were calculated with the Goldman-Hodgkin-Katz potential equation from the measured changes of reversal potentials. 3. Hydroxylammonium+, hydrazinium+ and methylammonium+, which are molecules of very similar shape and size, permeate the channel with very different permeability ratios: 5.92, 1.99 and 0.60 respectively. 4. Methylated and ethylated ammonium+ compounds were investigated. It was found that, not only methylammonium+, but also dimethylammonium+ and ethylammonium+ were permeant with permeability ratios of 0.6, 0.14 and 0.16 respectively. Trimethylammonium+, tetramethylammonium+, diethylammonium+, triethylammonium+, and tetraethylammonium+ were not permeant. 5. Guanidinium+ and its derivatives formamidinium+, aminoguanidinium+, acetamidinium+ and methylguanidinium+ were all permeant with permeability ratios 1.12, 1.00, 0.63, 0.36 and 0.33 respectively. 6. The cGMP-activated channel was found to be permeable to at least thirteen organic cations. Molecular models of the permeant cations indicate that the cross-section of the narrowest part of the pore must be at least as large as a rectangle of 0.38 x 0.5 nm dimensions. PMID:7683718

Presence of Ca2+-dependent K+ channels in chemosensory cilia support a role in odor transduction.

PubMed

Delgado, Ricardo; Saavedra, M Veronica; Schmachtenberg, Oliver; Sierralta, Jimena; Bacigalupo, Juan

2003-09-01

Olfactory receptor neurons (ORNs) respond to odorants with changes in the action potential firing rate. Excitatory responses, consisting of firing increases, are mediated by a cyclic AMP cascade that leads to the activation of cationic nonselective cyclic nucleotide-gated (CNG) channels and Ca2+-dependent Cl- (ClCa) channels. This process takes place in the olfactory cilia, where all protein components of this cascade are confined. ORNs from various vertebrate species have also been shown to generate inhibitory odor responses, expressed as decreases in action potential discharges. Odor inhibition appears to rely on Ca2+-dependent K+ (KCa) channels, but the underlying transduction mechanism remains unknown. If these channels are involved in odor transduction, they are expected to be present in the olfactory cilia. We found that a specific antibody against a large conductance KCa recognized a protein of approximately 116 kDa in Western blots of purified rat olfactory ciliary membranes. Moreover, the antibody labeled ORN cilia in isolated ORNs from rat and toad (Caudiverbera caudiverbera). In addition, single-channel recordings from inside-out membrane patches excised from toad chemosensory cilia showed the presence of 4 different types of KCa channels, with unitary conductances of 210, 60, 12, and 29 and 60 pS, high K+-selectivity, and Ca2+ sensitivities in the low micromolar range. Our work demonstrates the presence of K+ channels in the ORN cilia and supports their participation in odor transduction.

An EP2 Agonist Facilitates NMDA-Induced Outward Currents and Inhibits Dendritic Beading through Activation of BK Channels in Mouse Cortical Neurons

PubMed Central

Hayashi, Yoshinori; Morinaga, Saori; Liu, Xia; Zhang, Jing; Wu, Zhou; Yokoyama, Takeshi; Nakanishi, Hiroshi

2016-01-01

Prostaglandin E2 (PGE2), a major metabolite of arachidonic acid produced by cyclooxygenase pathways, exerts its bioactive responses by activating four E-prostanoid receptor subtypes, EP1, EP2, EP3, and EP4. PGE2 enables modulating N-methyl-D-aspartate (NMDA) receptor-mediated responses. However, the effect of E-prostanoid receptor agonists on large-conductance Ca2+-activated K+ (BK) channels, which are functionally coupled with NMDA receptors, remains unclear. Here, we showed that EP2 receptor-mediated signaling pathways increased NMDA-induced outward currents (I NMDA-OUT), which are associated with the BK channel activation. Patch-clamp recordings from the acutely dissociated mouse cortical neurons revealed that an EP2 receptor agonist activated I NMDA-OUT, whereas an EP3 receptor agonist reduced it. Agonists of EP1 or EP4 receptors showed no significant effects on I NMDA-OUT. A direct perfusion of 3,5′-cyclic adenosine monophosphate (cAMP) through the patch pipette facilitated I NMDA-OUT, which was abolished by the presence of protein kinase A (PKA) inhibitor. Furthermore, facilitation of I NMDA-OUT caused by an EP2 receptor agonist was significantly suppressed by PKA inhibitor. Finally, the activation of BK channels through EP2 receptors facilitated the recovery phase of NMDA-induced dendritic beading in the primary cultured cortical neurons. These results suggest that a direct activation of BK channels by EP2 receptor-mediated signaling pathways plays neuroprotective roles in cortical neurons. PMID:27298516

The luminal K+ channel of the thick ascending limb of Henle's loop.

PubMed

Bleich, M; Schlatter, E; Greger, R

1990-01-01

In vitro perfused rat thick ascending limbs of Henle's loop (TAL) were used (n = 260) to analyse the conductance properties of the luminal membrane applying the patch-clamp technique. Medullary (mTAL) and cortical (cTAL) tubule segments were dissected and perfused in vitro. The free end of the tubule was held and immobilized at one edge by a holding pipette kept under continuous suction. A micropositioner was used to insert a patch pipette into the lumen, and a gigaohm seal with the luminal membrane was achieved in 455 instances out of considerably more trials. In approximately 20% of all gigaohm seals recordings of single ionic channels were obtained. We have identified only one single type of K+ channel in these cell-attached and cell-excised recordings. In the cell-attached configuration with KCl or NaCl in the pipette, the channel had a conductance of 60 +/- 6 pS (n = 24) and 31 +/- 7 pS (n = 4) respectively. In cell-free patches with KCl either in the patch pipette or in the bath and with a Ringer-type solution (NaCl) on the opposite side the conductance was 72 +/- 4 pS (n = 37) at a clamp voltage of 0 mV. The permeability was 0.33 +/- 0.02 . 10(-12) cm3/s. The selectivity sequence of this channel was: K+ = Rb+ = NH4+ = Cs+ greater than Li+ much greater than Na+ = 0; the conductance sequence was K+ much greater than Li+ much greater than Rb+ = Cs+ = NH4+ = Na+ = 0. In excised patches Rb+, Cs+ and NH4+ when present in the bath at 145 mmol/l all inhibited K+ currents out of the pipette. The channel kinetics were described by one open (9.5 +/- 1.5 ms, n = 18) and by two closed (1.4 +/- 0.1 and 14 +/- 2 ms) time constants. The open probability of this channel was increased by depolarization. The channel open probability was reduced voltage dependently by Ba2+ (half maximal inhibition at 0 mV: 0.07 mmol/l) from the cytosolic side. Verapamil, diltiazem, quinine and quinidine inhibited at approximately 1 mumol/l -0.1 mmol/l from either side. Similarly, the amino cations lidocaine, tetraethylammonium and choline inhibited at 10-100 mmol/l. The channel was downregulated in its open probability by cytosolic Ca2+ activities greater than 10(-7) mol/l and by adenosine triphosphate greater than or equal to 10(-4) mol/l. The open probability was downregulated by decreasing cytosolic pH (2-fold by a decrease in pH by less than or equal to 0.2 units).(ABSTRACT TRUNCATED AT 400 WORDS)

Changes in body temperature in king penguins at sea: the result of fine adjustments in peripheral heat loss?

PubMed

Schmidt, Alexander; Alard, Frank; Handrich, Yves

2006-09-01

To investigate thermoregulatory adjustments at sea, body temperatures (the pectoral muscle and the brood patch) and diving behavior were monitored during a foraging trip of several days at sea in six breeding king penguins Aptenodytes patagonicus. During inactive phases at sea (water temperature: 4-7 degrees C), all tissues measured were maintained at normothermic temperatures. The brood patch temperature was maintained at the same values as those measured when brooding on shore (38 degrees C). This high temperature difference causes a significant loss of heat. We hypothesize that high-energy expenditure associated with elevated peripheral temperature when resting at sea is the thermoregulatory cost that a postabsorptive penguin has to face for the restoration of its subcutaneous body fat. During diving, mean pectoral temperature was 37.6 +/- 1.6 degrees C. While being almost normothermic on average, the temperature of the pectoral muscle was still significantly lower than during inactivity in five out of the six birds and underwent temperature drops of up to 5.5 degrees C. Mean brood patch temperature was 29.6 +/- 2.5 degrees C during diving, and temperature decreases of up to 21.6 degrees C were recorded. Interestingly, we observed episodes of brood patch warming during the descent to depth, suggesting that, in some cases, king penguins may perform active thermolysis using the brood patch. It is hypothesized that functional pectoral temperature may be regulated through peripheral adjustments in blood perfusion. These two paradoxical features, i.e., lower temperature of deep tissues during activity and normothermic peripheral tissues while inactive, may highlight the key to the energetics of this diving endotherm while foraging at sea.

Structure-Based Low-Rank Model With Graph Nuclear Norm Regularization for Noise Removal.

PubMed

Ge, Qi; Jing, Xiao-Yuan; Wu, Fei; Wei, Zhi-Hui; Xiao, Liang; Shao, Wen-Ze; Yue, Dong; Li, Hai-Bo

2017-07-01

Nonlocal image representation methods, including group-based sparse coding and block-matching 3-D filtering, have shown their great performance in application to low-level tasks. The nonlocal prior is extracted from each group consisting of patches with similar intensities. Grouping patches based on intensity similarity, however, gives rise to disturbance and inaccuracy in estimation of the true images. To address this problem, we propose a structure-based low-rank model with graph nuclear norm regularization. We exploit the local manifold structure inside a patch and group the patches by the distance metric of manifold structure. With the manifold structure information, a graph nuclear norm regularization is established and incorporated into a low-rank approximation model. We then prove that the graph-based regularization is equivalent to a weighted nuclear norm and the proposed model can be solved by a weighted singular-value thresholding algorithm. Extensive experiments on additive white Gaussian noise removal and mixed noise removal demonstrate that the proposed method achieves a better performance than several state-of-the-art algorithms.

The Effect of Silver Chloride Formation on the Kinetics of Silver Dissolution in Chloride Solution

PubMed Central

Ha, Hung; Payer, Joe

2011-01-01

The precipitation and growth of AgCl on silver in physiological NaCl solution were investigated. AgCl was found to form at bottom of scratches on the surface which may be the less effective sites for diffusion or the favorable sites for heterogeneous nucleation. Patches of silver chloride expanded laterally on the substrate until a continuous film formed. The ionic transport path through this newly formed continuous film was via spaces between AgCl patches. As the film grew, the spaces between AgCl patches closed and ion transport was primarily via micro-channels running through AgCl patches. The decrease of AgCl layer conductivity during film growth were attributed to the clogging of micro-channels or decrease in charge carrier concentration inside the micro-channels. Under thin AgCl layer, i.e. on the order of a micrometer, the dissolution of silver substrate was under mixed activation-Ohmic control. Under thick AgCl layer, i.e. on the order of tens of micrometers, the dissolution of silver substrate was mediated by the Ohmic resistance of AgCl layer. PMID:21516171

Multimedia Content Production inside the Classroom--A Teaching Proposal for Journalism and Audiovisual Communication Students

ERIC Educational Resources Information Center

Curiel, Eva Herrero; Serrano, Nieves Limón

2014-01-01

The main objective of this article is to present and describe two multimedia experiences carried out during two practice groups in the Journalism and Audiovisual Communications program. Thirty students participated in Experience A during 14 teaching sessions, and the experience required each student to record a 3-minute interview of someone…

Novel KCNQ2 channel activators discovered using fluorescence-based and automated patch-clamp-based high-throughput screening techniques

PubMed Central

Yue, Jin-feng; Qiao, Guan-hua; Liu, Ni; Nan, Fa-jun; Gao, Zhao-bing

2016-01-01

Aim: To establish an improved, high-throughput screening techniques for identifying novel KCNQ2 channel activators. Methods: KCNQ2 channels were stably expressed in CHO cells (KCNQ2 cells). Thallium flux assay was used for primary screening, and 384-well automated patch-clamp IonWorks Barracuda was used for hit validation. Two validated activators were characterized using a conventional patch-clamp recording technique. Results: From a collection of 80 000 compounds, the primary screening revealed a total of 565 compounds that potentiated the fluorescence signals in thallium flux assay by more than 150%. When the 565 hits were examined in IonWorks Barracuda, 38 compounds significantly enhanced the outward currents recorded in KCNQ2 cells, and were confirmed as KCNQ2 activators. In the conventional patch-clamp recordings, two validated activators ZG1732 and ZG2083 enhanced KCNQ2 currents with EC50 values of 1.04±0.18 μmol/L and 1.37±0.06 μmol/L, respectively. Conclusion: The combination of thallium flux assay and IonWorks Barracuda assay is an efficient high-throughput screening (HTS) route for discovering KCNQ2 activators. PMID:26725738

Temporal and Spatial Dispersal of Cladobotryum Conidia in the Controlled Environment of a Mushroom Growing Room▿

PubMed Central

Adie, Bruce; Grogan, Helen; Archer, Simon; Mills, Peter

2006-01-01

Cladobotryum spp. are responsible for cobweb disease of mushrooms. In two commercial and one experimental mushroom-growing room, Cladobotryum conidia were released into the air in direct response to physical disturbance of disease colonies during either crop watering or treatment by covering with salt to 10 mm. Conidia were detected using a Burkard spore trap or agar-based trap plates. A maximum concentration of ∼25,000 conidia m−3 was recorded in a small (75-m3) experimental growing room in the hour following the salting of 16 cobweb patches (0.55 m2). Concentrations of 100 and 40 conidia m−3 were recorded in the two larger commercial growing rooms in the hour following the salting of 18 and 11 patches of cobweb (diameter, approximately 50 to 200 mm), respectively. In controlled experiments, disturbed conidia were dispersed rapidly throughout a small growing room, with 91 to 97% of conidia settling out within 15 min. Eighty-five percent of conidia settled out within a 0.5-m radius when air-conditioning fans were switched off, consistent with airborne spore dispersal. Alternative methods for treating diseased areas to minimize conidial release and distribution were investigated and included covering disease colonies with damp paper tissue prior to salt application (tissue salting) and holding a dust extractor above disease colonies during salt application. Both methods resulted in no detectable airborne conidia, but the tissue paper salting technique was more convenient. Prevention of airborne conidial release and distribution is essential to avoid mushroom spotting symptoms, secondary colonies, and early crop termination. PMID:16980426

Vegetation-induced spatial variability of soil redox properties in wetlands

NASA Astrophysics Data System (ADS)

Szalai, Zoltán; Jakab, Gergely; Kiss, Klaudia; Ringer, Marianna; Balázs, Réka; Zacháry, Dóra; Horváth Szabó, Kata; Perényi, Katalin

2016-04-01

Vegetation induced land patches may result spatial pattern of on soil Eh and pH. These spatial pattern are mainly emerged by differences of aeration and exudation of assimilates. Present paper focuses on vertical extent and temporal dynamics of these patterns in wetlands. Two study sites were selected: 1. a plain wetland on calcareous sandy parent material (Ceglédbercel, Danube-Tisza Interfluve, Hungary); 2. headwater wetland with calcareous loamy parent material (Bátaapáti, Hungary). Two vegetation patches were studied in site 1: sedgy (dominated by Carex riparia) and reedy (dominated by Phragmites australis). Three patches were studied in site2: sedgy1 (dominated by C vulpina), sedgy 2 (C. riparia); nettle-horsetail (Urtica dioica and Equisetum arvense). Boundaries between patches were studied separately. Soil redox, pH and temperature studied by automated remote controlled instruments. Three digital sensors (Ponsell) were installed in each locations: 20cm and 40cm sensors represent the solum and 100 cm sensor monitors the subsoil). Groundwater wells were installed near to triplets for soil water sampling. Soil Eh, pH and temperature values were recorded in each 10 minutes. Soil water sampling for iron and DOC were carried out during saturated periods. Spatial pattern of soil Eh is clearly caused by vegetation. We measured significant differences between Eh values of the studied patches in the solum. We did not find this kinds horizontal differences in the subsoil. Boundaries of the patches usually had more reductive soil environment than the core areas. We have found temporal dynamics of the spatial redox pattern. Differences were not so well expressed during wintertime. These spatial patterns had influence on the DOC and iron content of porewater, as well. Highest temporal dynamics of soil redox properties and porewater iron could be found in the boundaries. These observations refer to importance patchiness of vegetation on soil chemical properties in wetlands. Authors are grateful to Hungarian Scientific research Fund (K100180)

Recommendation to test limonene hydroperoxides 0·3% and linalool hydroperoxides 1·0% in the British baseline patch test series.

PubMed

Wlodek, C; Penfold, C M; Bourke, J F; Chowdhury, M M U; Cooper, S M; Ghaffar, S; Green, C; Holden, C R; Johnston, G A; Mughal, A A; Reckling, C; Sabroe, R A; Stone, N M; Thompson, D; Wilkinson, S M; Buckley, D A

2017-12-01

There is a significant rate of sensitization worldwide to the oxidized fragrance terpenes limonene and linalool. Patch testing to oxidized terpenes is not routinely carried out; the ideal patch test concentration is unknown. To determine the best test concentrations for limonene and linalool hydroperoxides, added to the British baseline patch test series, to optimize detection of true allergy and to minimize irritant reactions. During 2013-2014, 4563 consecutive patients in 12 U.K. centres were tested to hydroperoxides of limonene in petrolatum (pet.) 0·3%, 0·2% and 0·1%, and hydroperoxides of linalool 1·0%, 0·5% and 0·25% pet. Irritant reactions were recorded separately from doubtful reactions. Concomitant reactions to other fragrance markers and clinical relevance were documented. Limonene hydroperoxide 0·3% gave positive reactions in 241 (5·3%) patients, irritant reactions in 93 (2·0%) and doubtful reactions in 110 (2·4%). Linalool hydroperoxide 1·0% gave positive reactions in 352 (7·7%), irritant reactions in 178 (3·9%) and doubtful reactions in 132 (2·9%). A total of 119 patients with crescendo reactions to 0·3% limonene would have been missed if only tested with 0·1% and 131 patients with crescendo reactions to 1·0% linalool would have been missed if only tested with 0·25%. In almost two-thirds of patients with positive patch tests to limonene and linalool the reaction was clinically relevant. The majority of patients did not react to any fragrance marker in the baseline series. We recommend that limonene hydroperoxides be tested at 0·3% and linalool hydroperoxides at 1·0% in the British baseline patch test series. © 2017 British Association of Dermatologists.

Microchip amplifier for in vitro, in vivo, and automated whole cell patch-clamp recording

PubMed Central

Kolb, Ilya; Kodandaramaiah, Suhasa B.; Chubykin, Alexander A.; Yang, Aimei; Bear, Mark F.; Boyden, Edward S.; Forest, Craig R.

2014-01-01

Patch clamping is a gold-standard electrophysiology technique that has the temporal resolution and signal-to-noise ratio capable of reporting single ion channel currents, as well as electrical activity of excitable single cells. Despite its usefulness and decades of development, the amplifiers required for patch clamping are expensive and bulky. This has limited the scalability and throughput of patch clamping for single-ion channel and single-cell analyses. In this work, we have developed a custom patch-clamp amplifier microchip that can be fabricated using standard commercial silicon processes capable of performing both voltage- and current-clamp measurements. A key innovation is the use of nonlinear feedback elements in the voltage-clamp amplifier circuit to convert measured currents into logarithmically encoded voltages, thereby eliminating the need for large high-valued resistors, a factor that has limited previous attempts at integration. Benchtop characterization of the chip shows low levels of current noise [1.1 pA root mean square (rms) over 5 kHz] during voltage-clamp measurements and low levels of voltage noise (8.2 μV rms over 10 kHz) during current-clamp measurements. We demonstrate the ability of the chip to perform both current- and voltage-clamp measurement in vitro in HEK293FT cells and cultured neurons. We also demonstrate its ability to perform in vivo recordings as part of a robotic patch-clamping system. The performance of the patch-clamp amplifier microchip compares favorably with much larger commercial instrumentation, enabling benchtop commoditization, miniaturization, and scalable patch-clamp instrumentation. PMID:25429119

46 CFR 59.10-20 - Patches in shells and tube sheets.

Code of Federal Regulations, 2010 CFR

2010-10-01

... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service... inside the drum or shell and sealed against leakage by welding. Such plates shall have a diameter of at... wasted portion with a new section. The ligaments between the tube holes may be joined by means of welding...

46 CFR 59.10-20 - Patches in shells and tube sheets.

Code of Federal Regulations, 2012 CFR

2012-10-01

... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service... inside the drum or shell and sealed against leakage by welding. Such plates shall have a diameter of at... wasted portion with a new section. The ligaments between the tube holes may be joined by means of welding...

46 CFR 59.10-20 - Patches in shells and tube sheets.

Code of Federal Regulations, 2011 CFR

2011-10-01

... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service... inside the drum or shell and sealed against leakage by welding. Such plates shall have a diameter of at... wasted portion with a new section. The ligaments between the tube holes may be joined by means of welding...

46 CFR 59.10-20 - Patches in shells and tube sheets.

Code of Federal Regulations, 2014 CFR

2014-10-01

... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service... inside the drum or shell and sealed against leakage by welding. Such plates shall have a diameter of at... wasted portion with a new section. The ligaments between the tube holes may be joined by means of welding...

46 CFR 59.10-20 - Patches in shells and tube sheets.

Code of Federal Regulations, 2013 CFR

2013-10-01

... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Boilers and Pressure Vessels in -Service... inside the drum or shell and sealed against leakage by welding. Such plates shall have a diameter of at... wasted portion with a new section. The ligaments between the tube holes may be joined by means of welding...

Comprehensive study of the intestinal stage of listeriosis in a rat ligated ileal loop system.

PubMed

Pron, B; Boumaila, C; Jaubert, F; Sarnacki, S; Monnet, J P; Berche, P; Gaillard, J L

1998-02-01

The intestinal stage of listeriosis was studied in a rat ligated ileal loop system. Listeria monocytogenes translocated to deep organs with similar efficiencies after inoculation of loops with or without Peyer's patches. Bacterial seeding of deep organs was demonstrated as early as 15 min after inoculation. It was dose dependent and nonspecific, as the delta inlAB, the delta hly, and the delta actA L. monocytogenes mutants and the nonpathogenic species, Listeria innocua, translocated similarly to wild-type L. monocytogenes strains. The levels of uptake of listeriae by Peyer's patches and villous intestine were similar and low, 50 to 250 CFU per cm2 of tissue. No listeria cells crossing the epithelial sheet of Peyer's patches and villous intestine were observed by transmission electron microscopy. The lack of significant interaction of listeriae and the follicle-associated epithelium of Peyer's patches was confirmed by scanning electron microscopy. The follicular tissue of Peyer's patches was a preferential site of Listeria replication. With all doses tested, the rate of bacterial growth was 10 to 20 times higher in Peyer's patches than in villous intestine. At early stages of Peyer's patch infection, listeriae were observed inside mononuclear cells of the dome area. Listeriae then disseminated throughout the follicular tissue except for the germinal center. The virulence determinants hly and, to a lesser extent, actA, but not inlAB, were required for the completion of this process. This study suggests that Peyer's patches are preferential sites for replication rather than for entry of L. monocytogenes, due to the presence of highly permissive mononuclear cells whose nature remains to be defined.

Comprehensive Study of the Intestinal Stage of Listeriosis in a Rat Ligated Ileal Loop System

PubMed Central

Pron, Benedicte; Boumaila, Claire; Jaubert, Francis; Sarnacki, Sabine; Monnet, Jean-Paul; Berche, Patrick; Gaillard, Jean-Louis

1998-01-01

The intestinal stage of listeriosis was studied in a rat ligated ileal loop system. Listeria monocytogenes translocated to deep organs with similar efficiencies after inoculation of loops with or without Peyer’s patches. Bacterial seeding of deep organs was demonstrated as early as 15 min after inoculation. It was dose dependent and nonspecific, as the ΔinlAB, the Δhly, and the ΔactA L. monocytogenes mutants and the nonpathogenic species, Listeria innocua, translocated similarly to wild-type L. monocytogenes strains. The levels of uptake of listeriae by Peyer’s patches and villous intestine were similar and low, 50 to 250 CFU per cm2 of tissue. No listeria cells crossing the epithelial sheet of Peyer’s patches and villous intestine were observed by transmission electron microscopy. The lack of significant interaction of listeriae and the follicle-associated epithelium of Peyer’s patches was confirmed by scanning electron microscopy. The follicular tissue of Peyer’s patches was a preferential site of Listeria replication. With all doses tested, the rate of bacterial growth was 10 to 20 times higher in Peyer’s patches than in villous intestine. At early stages of Peyer’s patch infection, listeriae were observed inside mononuclear cells of the dome area. Listeriae then disseminated throughout the follicular tissue except for the germinal center. The virulence determinants hly and, to a lesser extent, actA, but not inlAB, were required for the completion of this process. This study suggests that Peyer’s patches are preferential sites for replication rather than for entry of L. monocytogenes, due to the presence of highly permissive mononuclear cells whose nature remains to be defined. PMID:9453636

Non-Intrusive, Distributed Gas Sensing Technology for Advanced Spacesuits

NASA Technical Reports Server (NTRS)

Delgado, Jesus; Phillips, Straun; Rubtsov, Vladimir; Chullen, Cinda

2015-01-01

Chemical sensors for monitoring gas composition, including oxygen, humidity, carbon dioxide, and trace contaminants are needed to characterize and validate spacesuit design and operating parameters. This paper reports on the first prototypes of a non-intrusive gas sensing technology based on flexible sensitive patches positioned inside spacesuit prototypes and interrogated by optical fibers routed outside the suit, taking advantage of the transparent materials of the suit prototypes. The sensitive patches are based on luminescent materials whose emission parameters vary with the partial pressure of a specific gas. Patches sensitive to carbon dioxide, humidity, oxygen, and ammonia have been developed, and their preliminary characterization in the laboratory using Mark III-like helmet parts is described. The first prototype system consists of a four-channel fiber optic luminescent detector that can be used to monitor any of the selected target gases at four locations. To switch from one gas to another we replace the (disposable) sensor patches and adjust the system settings. Repeatability among sensitive patches and of sensor performance from location to location has been confirmed, assuring that suit engineers will have flexibility in selecting multiple sensing points, fitting the sensor elements into the spacesuit, and easily repositioning the sensor elements as desired. The evaluation of the first prototype for monitoring carbon dioxide during washout studies in a space suit prototype is presented.

Non-Intrusive, Distributed Gas Sensing Technology for Advanced Spacesuits

NASA Technical Reports Server (NTRS)

Delgado, Jesus; Phillips, Straun; Rubtsov, Vladimir; Chullen, Cinda

2015-01-01

Chemical sensors for monitoring gas composition, including oxygen, humidity, carbon dioxide, and trace contaminants, are needed to characterize and validate spacesuit design and operating parameters. This paper reports on the first prototypes of a non-intrusive gas sensing technology based on flexible sensitive patches positioned inside spacesuit prototypes and interrogated via optical fibers routed outside the suit, taking advantage of the transparent materials of the suit prototypes. The sensitive patches are based on luminescent materials whose emission parameters vary with the partial pressure of a specific gas. Patches sensitive to carbon dioxide, humidity, and temperature have been developed, and their preliminary laboratory characterization in Mark III-like helmet parts is described. The first prototype system consists of a four-channel fiber optic luminescent detector that can be used to monitor any of the selected target gases at four locations. To switch from one gas to another we replace the (disposable) sensor patches and adjust the system settings. Repeatability among sensitive patches and of sensor performance from location to location has been confirmed, assuring that suit engineers will have flexibility in selecting multiple sensing points, fitting the sensor elements into the spacesuit, and easily repositioning the sensor elements as desired. The evaluation of the first prototype for monitoring carbon dioxide during washout studies in a spacesuit prototype is presented.

New contraceptive patch wearability assessed by investigators and participants in a randomized phase 3 study.

PubMed

Kaunitz, Andrew M; Portman, David; Westhoff, Carolyn L; Mishell, Daniel R; Archer, David F; Foegh, Marie

2015-03-01

To evaluate skin irritation and patch adhesiveness of a new weekly low-dose levonorgestrel (LNG) and ethinyl estradiol (EE) contraceptive patch (LNG/EE patch). This analysis was part of an open-label, parallel-group, multicenter, phase 3 study that randomized healthy women to the LNG/EE patch (one patch weekly for three consecutive weeks, followed by a patch-free week for 13 cycles) or to an oral contraceptive for six cycles followed by seven LNG/EE patch cycles. Participants selected patch application sites of abdomen, buttock or upper torso. Investigators rated patch adhesiveness and skin irritation using standardized scales. Participants rated skin irritation and itching daily using standardized scales and recorded patch fall-off on daily diary cards. A total of 32,508 patches were applied (n=1273). At the five clinic visits in which investigators rated the patches, they rated adhesiveness=0 (no lift) for ≥84% of participants and skin irritation=absent/mild for 97% of patches. Participants reported that 2-3.7% of patches fell off and rated skin irritation as absent or mild for 92- 95% of patches, according to site. Investigator- and participant-rated assessments of LNG/EE patch adhesiveness and irritation demonstrated a low incidence of patch detachment, skin irritation and pruritus. This secondary analysis of a phase 3 clinical trial of a new weekly low-dose LNG and EE contraceptive patch, which used assessment by both investigators and participants, observed a low incidence of skin irritation, pruritus and patch detachment. Copyright © 2015 Elsevier Inc. All rights reserved.

SDSS IV MaNGA: the global and local stellar mass assemby histories of galaxies

NASA Astrophysics Data System (ADS)

Ibarra-Medel, Héctor J.; Sánchez, Sebastián F.; Avila-Reese, Vladimir; Hernández-Toledo, Héctor M.; González, J. Jesús; Drory, Niv; Bundy, Kevin; Bizyaev, Dmitry; Cano-Díaz, Mariana; Malanushenko, Elena; Pan, Kaike; Roman-Lopes, Alexandre; Thomas, Daniel

2016-12-01

Using the fossil record method implemented through Pipe3D, we reconstruct the global and radial stellar mass growth histories (MGHs) of a large sample of galaxies, ranging from dwarf to giant objects, from the Mapping Nearby Galaxies at the Apache Point Observatory (MaNGA) survey. We confirm that the main driver of the global MGHs is mass, with more massive galaxies assembling earlier (downsizing), though for a given mass, the global MGHs segregate by colour, specific star formation rate and morphological type. From the inferred radial mean MGHs, we find that at fractions of assembled mass larger than ˜80 per cent, the innermost regions formed stars, on average, in the inside-out mode. At earlier epochs, when the age estimation of the method becomes poor, the MGHs seem to be spatially homogeneous or even in the outside-in mode, especially for the red/quiescent/early-type galaxies. The innermost MGHs are, in general, less scattered around the mean than the outermost MGHs. For dwarf and low-mass galaxies, we do not find evidence of an outside-in formation mode; instead, their radial MGHs are very diverse most of the time, with periods of outside-in and inside-out modes (or strong radial migration), suggesting this is an episodic star formation history. Blue/star-forming/late-type galaxies present, on average, a significantly more pronounced inside-out formation mode than red/quiescent/early-type galaxies, independently of mass. We discuss our results in the light of the processes of galaxy formation, quenching and radial migration. We also discuss the uncertainties and biases of the fossil record method and how these could affect our results.

Diadenosine tetraphosphate-gating of recombinant pancreatic ATP-sensitive K(+) channels.

PubMed

Jovanovic, S; Jovanovic, A

2001-02-01

Diadenosine tetraphosphate (Ap4A) has been recently discovered in the pancreatic beta cells where targets ATP-sensitive K(+) (K(ATP)) channels, depolarizes the cell membrane and induces insulin secretion. However, whether Ap4A inhibit pancreatic K(ATP) channels by targeting protein channel complex itself was unknown. Therefore, we coexpressed pancreatic K(ATP) channel subunits, Kir6.2 and SUR1, in COS-7 cells and examined the effect of Ap4A on the single channel behavior using the inside-out configuration of the patch-clamp technique. Ap4A inhibited channel opening in a concentration-dependent manner. Analysis of single channels demonstrated that Ap4A did not change intraburst kinetic behavior of K(ATP) channels, but rather decreased burst duration and increased between-burst duration. It is concluded that Ap4A antagonizes K(ATP) channel opening by targeting channel subunits themselves and by keeping channels longer in closed interburst states.

A miniaturized micro strip antenna based on sinusoidal patch geometry for implantable biomedical applications

NASA Astrophysics Data System (ADS)

Ibrahim, Omar A.; Elwi, Taha A.; Islam, Naz E.

2012-11-01

A miniaturized microstrip antenna is analyzed for implantable biomedical applications. The antenna is designed using two different commercial software packages, CST Microwave Studio and HFSS, to validate the results. The proposed design operates in the WMTS frequency band. The antenna performance is tested inside the human body, Hugo model. The antenna design is readjusted to get the desired resonant frequency. The resonant frequency, bandwidth, gain, and radiation pattern of the proposed antenna are provided in this paper. Furthermore, the effect of losses inside human body due to the fat layer is recognized.

Comparison of Cell Expression Formats for the Characterization of GABAA Channels Using a Microfluidic Patch Clamp System

PubMed Central

Chen, Qin; Yim, Peter D.; Yuan, Nina; Johnson, Juliette; Cook, James M.; Smith, Steve; Ionescu-Zanetti, Cristian; Wang, Zhi-Jian; Arnold, Leggy A.

2012-01-01

Abstract Ensemble recording and microfluidic perfusion are recently introduced techniques aimed at removing the laborious nature and low recording success rates of manual patch clamp. Here, we present assay characteristics for these features integrated into one automated electrophysiology platform as applied to the study of GABAA channels. A variety of cell types and methods of GABAA channel expression were successfully studied (defined as IGABA>500 pA), including stably transfected human embryonic kidney (HEK) cells expressing α1β3γ2 GABAA channels, frozen ready-to-assay (RTA) HEK cells expressing α1β3γ2 or α3β3γ2 GABAA channels, transiently transfected HEK293T cells expressing α1β3γ2 GABAA channels, and immortalized cultures of human airway smooth muscle cells endogenously expressing GABAA channels. Current measurements were successfully studied in multiple cell types with multiple modes of channel expression in response to several classic GABAA channel agonists, antagonists, and allosteric modulators. We obtained success rates above 95% for transiently or stably transfected HEK cells and frozen RTA HEK cells expressing GABAA channels. Tissue-derived immortalized cultures of airway smooth muscle cells exhibited a slightly lower recording success rate of 75% using automated patch, which was much higher than the 5% success rate using manual patch clamp technique by the same research group. Responses to agonists, antagonists, and allosteric modulators compared well to previously reported manual patch results. The data demonstrate that both the biophysics and pharmacologic characterization of GABAA channels in a wide variety of cell formats can be performed using this automated patch clamp system. PMID:22574655

Industrializing electrophysiology: HT automated patch clamp on SyncroPatch® 96 using instant frozen cells.

PubMed

Polonchuk, Liudmila

2014-01-01

Patch-clamping is a powerful technique for investigating the ion channel function and regulation. However, its low throughput hampered profiling of large compound series in early drug development. Fortunately, automation has revolutionized the area of experimental electrophysiology over the past decade. Whereas the first automated patch-clamp instruments using the planar patch-clamp technology demonstrated rather a moderate throughput, few second-generation automated platforms recently launched by various companies have significantly increased ability to form a high number of high-resistance seals. Among them is SyncroPatch(®) 96 (Nanion Technologies GmbH, Munich, Germany), a fully automated giga-seal patch-clamp system with the highest throughput on the market. By recording from up to 96 cells simultaneously, the SyncroPatch(®) 96 allows to substantially increase throughput without compromising data quality. This chapter describes features of the innovative automated electrophysiology system and protocols used for a successful transfer of the established hERG assay to this high-throughput automated platform.

Human versus lightning ignition of presettlement surface fires in costal pine forests of the upper Great Lakes

USGS Publications Warehouse

Loope, Walter L.; Anderton, John B.

1998-01-01

To recover direct evidence of surface fires before European settlement, we sectioned fire-scarred logging-era stumps and trees in 39 small, physically isolated sand patches along the Great Lakes coast of northern Michigan and northern Wisconsin. While much information was lost to postharvest fire and stump deterioration, 147 fire-free intervals revealed in cross-sections from 29 coastal sand patches document numerous close interval surface fires before 1910; only one post-1910 fire was documented. Cross-sections from the 10 sections with records spanning >150 yr suggest local fire occurrence rates before 1910 ca. 10 times the present rate of lightning-caused fire. Since fire spread between or into coastal sand patches is rare, and seasonal use of the patches by Native people before 1910 is well documented, both historically and ethnographically, ignition by humans probably accounts for more than half of the pre-1910 fires recorded in cross-sections.

Transdermal patches: history, development and pharmacology.

PubMed

Pastore, Michael N; Kalia, Yogeshvar N; Horstmann, Michael; Roberts, Michael S

2015-05-01

Transdermal patches are now widely used as cosmetic, topical and transdermal delivery systems. These patches represent a key outcome from the growth in skin science, technology and expertise developed through trial and error, clinical observation and evidence-based studies that date back to the first existing human records. This review begins with the earliest topical therapies and traces topical delivery to the present-day transdermal patches, describing along the way the initial trials, devices and drug delivery systems that underpin current transdermal patches and their actives. This is followed by consideration of the evolution in the various patch designs and their limitations as well as requirements for actives to be used for transdermal delivery. The properties of and issues associated with the use of currently marketed products, such as variability, safety and regulatory aspects, are then described. The review concludes by examining future prospects for transdermal patches and drug delivery systems, such as the combination of active delivery systems with patches, minimally invasive microneedle patches and cutaneous solutions, including metered-dose systems. © 2015 The British Pharmacological Society.

The slow inward calcium current is responsible for a part of the contraction of patch-clamped rat myoballs.

PubMed

Rivet, M; Cognard, C; Raymond, G

1989-01-01

The slow inward calcium current and the contractile response were simultaneously recorded in voltage clamped (whole cell patch clamp recording) rat myoballs in primary culture. The shape of the contraction(T)/potential(V) relationship and the application of the inorganic calcium channel blocker cadmium (1.5 mM), which suppresses a part of the contractile activity, demonstrate the existence of two components of contraction. One of them is related to the slow calcium current.

Comparison of the efficacies of patching and penalization therapies for the treatment of amblyopia patients

PubMed Central

Cabi, Cemalettin; Sayman Muslubas, Isil Bahar; Aydin Oral, Ayse Yesim; Dastan, Metin

2014-01-01

AIM To compare the efficacies of patching and penalization therapies for the treatment of amblyopia patients. METHODS The records of 64 eyes of 50 patients 7 to 16y of age who had presented to our clinics with a diagnosis of amblyopia, were evaluated retrospectively. Forty eyes of 26 patients who had received patching therapy and 24 eyes of 24 patients who had received penalization therapy included in this study. The latencies and amplitudes of visual evoked potential (VEP) records and best corrected visual acuities (BCVA) of these two groups were compared before and six months after the treatment. RESULTS In both patching and the penalization groups, the visual acuities increased significantly following the treatments (P<0.05). The latency measurements of the P100 wave obtained at 1.0°, 15 arc min. Patterns of both groups significantly decreased following the 6-months-treatment. However, the amplitude measurements increased (P<0.05). CONCLUSION The patching and the penalization methods, which are the main methods used in the treatment of amblyopia, were also effective over the age of 7y, which has been accepted as the critical age for the treatment of amblyopia. PMID:24967195

Designing and testing a wearable, wireless fNIRS patch.

PubMed

Abtahi, Mohammadreza; Cay, Gozde; Saikia, Manob Jyoti; Mankodiya, Kunal

2016-08-01

Optical brain monitoring using near infrared (NIR) light has got a lot of attention in order to study the complexity of the brain due to several advantages as oppose to other methods such as EEG, fMRI and PET. There are a few commercially available functional NIR spectroscopy (fNIRS) brain monitoring systems, but they are still non-wearable and pose difficulties in scanning the brain while the participants are in motion. In this work, we present our endeavors to design and test a low-cost, wireless fNIRS patch using NIR light sources at wavelengths of 770 and 830nm, photodetectors and a microcontroller to trigger the light sources, read photodetector's output and transfer data wirelessly (via Bluetooth) to a smart-phone. The patch is essentially a 3-D printed wearable system, recording and displaying the brain hemodynamic responses on smartphone, also eliminates the need for complicated wiring of the electrodes. We have performed rigorous lab experiments on the presented system for its functionality. In a proof of concept experiment, the patch detected the NIR absorption on the arm. Another experiment revealed that the patch's battery could last up to several hours with continuous fNIRS recording with and without wireless data transfer.

Deep feature classification of angiomyolipoma without visible fat and renal cell carcinoma in abdominal contrast-enhanced CT images with texture image patches and hand-crafted feature concatenation.

PubMed

Lee, Hansang; Hong, Helen; Kim, Junmo; Jung, Dae Chul

2018-04-01

To develop an automatic deep feature classification (DFC) method for distinguishing benign angiomyolipoma without visible fat (AMLwvf) from malignant clear cell renal cell carcinoma (ccRCC) from abdominal contrast-enhanced computer tomography (CE CT) images. A dataset including 80 abdominal CT images of 39 AMLwvf and 41 ccRCC patients was used. We proposed a DFC method for differentiating the small renal masses (SRM) into AMLwvf and ccRCC using the combination of hand-crafted and deep features, and machine learning classifiers. First, 71-dimensional hand-crafted features (HCF) of texture and shape were extracted from the SRM contours. Second, 1000-4000-dimensional deep features (DF) were extracted from the ImageNet pretrained deep learning model with the SRM image patches. In DF extraction, we proposed the texture image patches (TIP) to emphasize the texture information inside the mass in DFs and reduce the mass size variability. Finally, the two features were concatenated and the random forest (RF) classifier was trained on these concatenated features to classify the types of SRMs. The proposed method was tested on our dataset using leave-one-out cross-validation and evaluated using accuracy, sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV), and area under receiver operating characteristics curve (AUC). In experiments, the combinations of four deep learning models, AlexNet, VGGNet, GoogleNet, and ResNet, and four input image patches, including original, masked, mass-size, and texture image patches, were compared and analyzed. In qualitative evaluation, we observed the change in feature distributions between the proposed and comparative methods using tSNE method. In quantitative evaluation, we evaluated and compared the classification results, and observed that (a) the proposed HCF + DF outperformed HCF-only and DF-only, (b) AlexNet showed generally the best performances among the CNN models, and (c) the proposed TIPs not only achieved the competitive performances among the input patches, but also steady performance regardless of CNN models. As a result, the proposed method achieved the accuracy of 76.6 ± 1.4% for the proposed HCF + DF with AlexNet and TIPs, which improved the accuracy by 6.6%p and 8.3%p compared to HCF-only and DF-only, respectively. The proposed shape features and TIPs improved the HCFs and DFs, respectively, and the feature concatenation further enhanced the quality of features for differentiating AMLwvf from ccRCC in abdominal CE CT images. © 2018 American Association of Physicists in Medicine.

Synthesis and characterization of modified starch/polybutadiene as novel transdermal drug delivery system.

PubMed

Saboktakin, Mohammad Reza; Akhyari, Shahab; Nasirov, Fizuli A

2014-08-01

Transdermal drug delivery systems are topically administered medicaments in the form of patches that deliver drugs for systemic effects at a predetermined and controlled rate. It works very simply in which drug is applied inside the patch and it is worn on skin for long period of time. Polymer matrix, drug, permeation enhancers are the main components of transdermal drug delivery systems. The objective of the present study was to develop the modified starch and 1,4-cis polybutadiene nanoparticles as novel polymer matrix system. We have been studied the properties of a novel transdermal drug delivery system with clonidine as drug model. Copyright © 2014 Elsevier B.V. All rights reserved.

On the effects of nonlinear boundary conditions in diffusive logistic equations on bounded domains

NASA Astrophysics Data System (ADS)

Cantrell, Robert Stephen; Cosner, Chris

We study a diffusive logistic equation with nonlinear boundary conditions. The equation arises as a model for a population that grows logistically inside a patch and crosses the patch boundary at a rate that depends on the population density. Specifically, the rate at which the population crosses the boundary is assumed to decrease as the density of the population increases. The model is motivated by empirical work on the Glanville fritillary butterfly. We derive local and global bifurcation results which show that the model can have multiple equilibria and in some parameter ranges can support Allee effects. The analysis leads to eigenvalue problems with nonstandard boundary conditions.

Activation of TRPV1 channels inhibits mechanosensitive Piezo channel activity by depleting membrane phosphoinositides

PubMed Central

Borbiro, Istvan; Badheka, Doreen; Rohacs, Tibor

2015-01-01

Capsaicin is an activator of the heat-sensitive TRPV1 (transient receptor potential vanilloid 1) ion channels and has been used as a local analgesic. We found that activation of TRPV1 channels with capsaicin either in dorsal root ganglion neurons or in a heterologous expression system inhibited the mechanosensitive Piezo1 and Piezo2 channels by depleting phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and its precursor PI(4)P from the plasma membrane through Ca2+-induced phospholipase Cδ (PLCδ) activation. Experiments with chemically inducible phosphoinositide phosphatases and receptor-induced activation of PLCβ indicated that inhibition of Piezo channels required depletion of both PI(4)P and PI(4,5)P2. The mechanically activated current amplitudes decreased substantially in the excised inside-out configuration, where the membrane patch containing Piezo1 channels is removed from the cell. PI(4,5)P2 and PI(4)P applied to these excised patches inhibited this decrease. Thus, we concluded that Piezo channel activity requires the presence of phosphoinositides, and the combined depletion of PI(4,5)P2 or PI(4)P reduces channel activity. In addition to revealing a role for distinct membrane lipids in mechanosensitive ion channel regulation, these data suggest that inhibition of Piezo2 channels may contribute to the analgesic effect of capsaicin. PMID:25670203

On the use of electrical and optical strain gauges paired to magnetostrictive patch actuators

NASA Astrophysics Data System (ADS)

Braghin, Francesco; Cinquemani, Simone; Cazzulani, Gabriele; Comolli, Lorenzo

2014-04-01

Giant Magnetostrictive Actuators (GMA) can be profitably used in application of vibration control on smart structures. In this field, the use of inertial actuators based on magnetostrictive materials has been consolidate. Such devices turn out to be very effective in applications of vibration control, since they can be easily paired with sensors able to ensure the feedback signal necessary to perform the control action. Unlike most widespread applications, this paper studies the use of patch magnetostrictive actuators. They are made of a sheet of magnetostrictive material, rigidly constrained to the structure, and wrapped in a solenoid whose purpose is to change the intensity of the magnetic field within the material itself. The challenge in the use of such devices resides in the impossibility of having co-located sensors. This limit may be exceeded by using strain gauge sensors to measure the deformation of the structure at the actuator. This work analyzes experimentally the opportunity of introducing, inside a composite material structure, both the conventional electric strain gauges and the less conventional optical sensors based on Bragg's gratings. The performance of both solutions are analyzed with particular reference to the signal to noise ratio, the resolution of the sensors, the sensitivity to variations of the electric and magnetic fields and the temperature change associated with the operation of the actuator.

Design of Miniaturized Dual-Band Microstrip Antenna for WLAN Application

PubMed Central

Yang, Jiachen; Wang, Huanling; Lv, Zhihan; Wang, Huihui

2016-01-01

Wireless local area network (WLAN) is a technology that combines computer network with wireless communication technology. The 2.4 GHz and 5 GHz frequency bands in the Industrial Scientific Medical (ISM) band can be used in the WLAN environment. Because of the development of wireless communication technology and the use of the frequency bands without the need for authorization, the application of WLAN is becoming more and more extensive. As the key part of the WLAN system, the antenna must also be adapted to the development of WLAN communication technology. This paper designs two new dual-frequency microstrip antennas with the use of electromagnetic simulation software—High Frequency Structure Simulator (HFSS). The two antennas adopt ordinary FR4 material as a dielectric substrate, with the advantages of low cost and small size. The first antenna adopts microstrip line feeding, and the antenna radiation patch is composed of a folded T-shaped radiating dipole which reduces the antenna size, and two symmetrical rectangular patches located on both sides of the T-shaped radiating patch. The second antenna is a microstrip patch antenna fed by coaxial line, and the size of the antenna is diminished by opening a stepped groove on the two edges of the patch and a folded slot inside the patch. Simulation experiments prove that the two designed antennas have a higher gain and a favourable transmission characteristic in the working frequency range, which is in accordance with the requirements of WLAN communication. PMID:27355954

Design of Miniaturized Dual-Band Microstrip Antenna for WLAN Application.

PubMed

Yang, Jiachen; Wang, Huanling; Lv, Zhihan; Wang, Huihui

2016-06-27

Wireless local area network (WLAN) is a technology that combines computer network with wireless communication technology. The 2.4 GHz and 5 GHz frequency bands in the Industrial Scientific Medical (ISM) band can be used in the WLAN environment. Because of the development of wireless communication technology and the use of the frequency bands without the need for authorization, the application of WLAN is becoming more and more extensive. As the key part of the WLAN system, the antenna must also be adapted to the development of WLAN communication technology. This paper designs two new dual-frequency microstrip antennas with the use of electromagnetic simulation software-High Frequency Structure Simulator (HFSS). The two antennas adopt ordinary FR4 material as a dielectric substrate, with the advantages of low cost and small size. The first antenna adopts microstrip line feeding, and the antenna radiation patch is composed of a folded T-shaped radiating dipole which reduces the antenna size, and two symmetrical rectangular patches located on both sides of the T-shaped radiating patch. The second antenna is a microstrip patch antenna fed by coaxial line, and the size of the antenna is diminished by opening a stepped groove on the two edges of the patch and a folded slot inside the patch. Simulation experiments prove that the two designed antennas have a higher gain and a favourable transmission characteristic in the working frequency range, which is in accordance with the requirements of WLAN communication.

Conserving Tropical Tree Diversity and Forest Structure: The Value of Small Rainforest Patches in Moderately-Managed Landscapes

PubMed Central

Hernández-Ruedas, Manuel A.; Arroyo-Rodríguez, Víctor; Meave, Jorge A.; Martínez-Ramos, Miguel; Ibarra-Manríquez, Guillermo; Martínez, Esteban; Jamangapé, Gilberto; Melo, Felipe P. L.; Santos, Bráulio A.

2014-01-01

Rainforests are undergoing severe deforestation and fragmentation worldwide. A huge amount of small forest patches are being created, but their value in conserving biodiversity and forest structure is still controversial. Here, we demonstrate that in a species-rich and moderately-managed Mexican tropical landscape small rainforest patches (<100 ha) can be highly valuable for the conservation of tree diversity and forest structure. These patches showed diverse communities of native plants, including endangered species, and a new record for the country. Although the number of logged trees increased in smaller patches, patch size was a poor indicator of basal area, stem density, number of species, genera and families, and community evenness. Cumulative species-area curves indicated that all patches had a similar contribution to the regional species diversity. This idea also was supported by the fact that patches strongly differed in floristic composition (high β-diversity), independently of patch size. Thus, in agreement with the land-sharing approach, our findings support that small forest patches in moderately-managed landscapes should be included in conservation initiatives to maintain landscape heterogeneity, species diversity, and ecosystem services. PMID:24901954

Conserving tropical tree diversity and forest structure: the value of small rainforest patches in moderately-managed landscapes.

PubMed

Hernández-Ruedas, Manuel A; Arroyo-Rodríguez, Víctor; Meave, Jorge A; Martínez-Ramos, Miguel; Ibarra-Manríquez, Guillermo; Martínez, Esteban; Jamangapé, Gilberto; Melo, Felipe P L; Santos, Bráulio A

2014-01-01

Rainforests are undergoing severe deforestation and fragmentation worldwide. A huge amount of small forest patches are being created, but their value in conserving biodiversity and forest structure is still controversial. Here, we demonstrate that in a species-rich and moderately-managed Mexican tropical landscape small rainforest patches (<100 ha) can be highly valuable for the conservation of tree diversity and forest structure. These patches showed diverse communities of native plants, including endangered species, and a new record for the country. Although the number of logged trees increased in smaller patches, patch size was a poor indicator of basal area, stem density, number of species, genera and families, and community evenness. Cumulative species-area curves indicated that all patches had a similar contribution to the regional species diversity. This idea also was supported by the fact that patches strongly differed in floristic composition (high β-diversity), independently of patch size. Thus, in agreement with the land-sharing approach, our findings support that small forest patches in moderately-managed landscapes should be included in conservation initiatives to maintain landscape heterogeneity, species diversity, and ecosystem services.

Permeation Mechanisms in the TMEM16B Calcium-Activated Chloride Channels

PubMed Central

2017-01-01

TMEM16A and TMEM16B encode for Ca2+-activated Cl− channels (CaCC) and are expressed in many cell types and play a relevant role in many physiological processes. Here, I performed a site-directed mutagenesis study to understand the molecular mechanisms of ion permeation of TMEM16B. I mutated two positive charged residues R573 and K540, respectively located at the entrance and inside the putative channel pore and I measured the properties of wild-type and mutant TMEM16B channels expressed in HEK-293 cells using whole-cell and excised inside-out patch clamp experiments. I found evidence that R573 and K540 control the ion permeability of TMEM16B depending both on which side of the membrane the ion substitution occurs and on the level of channel activation. Moreover, these residues contribute to control blockage or activation by permeant anions. Finally, R573 mutation abolishes the anomalous mole fraction effect observed in the presence of a permeable anion and it alters the apparent Ca2+-sensitivity of the channel. These findings indicate that residues facing the putative channel pore are responsible both for controlling the ion selectivity and the gating of the channel, providing an initial understanding of molecular mechanism of ion permeation in TMEM16B. PMID:28046119

Dual patch voltage clamp study of low membrane resistance astrocytes in situ.

PubMed

Ma, Baofeng; Xu, Guangjin; Wang, Wei; Enyeart, John J; Zhou, Min

2014-03-17

Whole-cell patch clamp recording has been successfully used in identifying the voltage-dependent gating and conductance properties of ion channels in a variety of cells. However, this powerful technique is of limited value in studying low membrane resistance cells, such as astrocytes in situ, because of the inability to control or accurately measure the real amplitude of command voltages. To facilitate the study of ionic conductances of astrocytes, we have developed a dual patch recording method which permits membrane current and membrane potential to be simultaneously recorded from astrocytes in spite of their extraordinarily low membrane resistance. The utility of this technique is demonstrated by measuring the voltage-dependent activation of the inwardly rectifying K+ current abundantly expressed in astrocytes and multiple ionic events associated with astrocytic GABAA receptor activation. This protocol can be performed routinely in the study of astrocytes. This method will be valuable for identifying and characterizing the individual ion channels that orchestrate the electrical activity of low membrane resistance cells.

A practical method of determining water current velocities and diffusion coefficients in coastal waters by remote sensing techniques

NASA Technical Reports Server (NTRS)

James, W. P.

1971-01-01

A simplified procedure is presented for determining water current velocities and diffusion coefficients. Dye drops which form dye patches in the receiving water are made from an aircraft. The changes in position and size of the patches are recorded from two flights over the area. The simplified data processing procedure requires only that the ground coordinates about the dye patches be determined at the time of each flight. With an automatic recording coordinatograph for measuring coordinates and a computer for processing the data, this technique provides a practical method of determining circulation patterns and mixing characteristics of large aquatic systems. This information is useful in assessing the environmental impact of waste water discharges and for industrial plant siting.

The impact of orientation filtering on face-selective neurons in monkey inferior temporal cortex.

PubMed

Taubert, Jessica; Goffaux, Valerie; Van Belle, Goedele; Vanduffel, Wim; Vogels, Rufin

2016-02-16

Faces convey complex social signals to primates. These signals are tolerant of some image transformations (e.g. changes in size) but not others (e.g. picture-plane rotation). By filtering face stimuli for orientation content, studies of human behavior and brain responses have shown that face processing is tuned to selective orientation ranges. In the present study, for the first time, we recorded the responses of face-selective neurons in monkey inferior temporal (IT) cortex to intact and scrambled faces that were filtered to selectively preserve horizontal or vertical information. Guided by functional maps, we recorded neurons in the lateral middle patch (ML), the lateral anterior patch (AL), and an additional region located outside of the functionally defined face-patches (CONTROL). We found that neurons in ML preferred horizontal-passed faces over their vertical-passed counterparts. Neurons in AL, however, had a preference for vertical-passed faces, while neurons in CONTROL had no systematic preference. Importantly, orientation filtering did not modulate the firing rate of neurons to phase-scrambled face stimuli in any recording region. Together these results suggest that face-selective neurons found in the face-selective patches are differentially tuned to orientation content, with horizontal tuning in area ML and vertical tuning in area AL.

Direct laboratory observation of fluid distribution and its influence on acoustic properties of patchy saturated rocks

NASA Astrophysics Data System (ADS)

Lebedev, M.; Clennell, B.; Pervukhina, M.; Shulakova, V.; Mueller, T.; Gurevich, B.

2009-04-01

Porous rocks in hydrocarbon reservoirs are often saturated with a mixture of two or more fluids. Interpretation of exploration seismograms requires understanding of the relationship between distribution of the fluids patches and acoustic properties of rocks. The sizes of patches as well as their distribution affect significantly the seismic response. If the size of the fluid patch is smaller than the diffusion wavelength then pressure equilibration is achieved and the bulk modulus of the rock saturated with a mixture is defined by the Gassmann equations (Gassmann, 1951) with the saturation-weighted average of the fluid bulk modulus given by Wood's law (Wood, 1955, Mavko et al., 1998). If the fluid patch size is much larger than the diffusion wavelength then there is no pressure communication between different patches. In this case, fluid-flow effects can be neglected and the overall rock may be considered equivalent to an elastic composite material consisting of homogeneous parts whose properties are given by Gassmann theory with Hill's equation for the bulk modulus (Hill, 1963, Mavko et al., 1998). At intermediate values of fluid saturation the velocity-saturation relationship is significantly affected by the fluid patch distribution. In order to get an improved understanding of factors influencing the patch distribution and the resulting seismic wave response we performed simultaneous measurements of P-wave velocities and rock sample CT imaging. The CT imaging allows us to map the fluid distribution inside rock sample during saturation (water imbibition). We compare the experimental results with theoretical predictions. In this paper we will present results of simultaneous measurements of longitudinal wave velocities and imaging mapping of fluid distribution inside rock sample during sample saturation. We will report results of two kinds of experiments: "dynamic" and "quasi static" saturation. In both experiments Casino Cores Otway Basin sandstone, Australia core samples (38 mm in diameter, approximately 60 mm long) were dried in oven under reduced pressure. In dynamic saturation experiments, samples were jacketed in the experimental cell, made from transparent for X-radiation material (PMMA). Distillate water was injected into the sample from the one side. Fluid distribution in such "dynamic" experiment: both spatial and time dependant was measured using X-ray Computer Tomograph (CT) with resolution 0.2 x 0.2 x 1 mm3. Velocities (Vp, and Vs) at ultrasonic frequency of 1 MHz, were measured in the direction perpendicular to initial direction of the fluid flow injection. Sample saturation was estimated from the CT results. In "quasi static" experiments samples were saturated during long period of time (over 2 weeks) to achieve uniform distribution of liquid inside the sample. Saturation was determined by measurement of the weight of water fraction. All experiments were performed at laboratory environments at temperature 25 C. Ultrasonic velocities and fluid saturations were measured simultaneously during water injection into sandstone core samples. The experimental results obtained on low-permeability samples show that at low saturation values the velocity-saturation dependence can be described by the Gassmann-Wood relationship. However, with increasing saturation a sharp increase of P-wave velocity is observed, eventually approaching the Gassmann-Hill relationship. We connect the characteristics of the transition behavior of the velocity-saturation relationships to the increasing size of the patches inside the rock sample. In particular, we show that for relatively large fluid injection rate this transition occurs at smaller degrees of saturation as compared with high injection rate. We model the experimental data using the so-called White model (Toms 2007) that assumes fluid patch distribution as a periodic assemblage of concentric spheres. We can observe reasonable agreement between experimental results and theoretical predictions of White's model. The results illustrate the non-unique relationships between saturation and velocity in sandstones dependent on texture and fluid displacement history: fuller understanding of these phenomena is needed for accurate assessment of time lapse seismic measurements, be they for oil and gas recovery or for CO2 disposal purposes. Gassmann, F., 1951, Elastic waves through a packing of spheres. Geophysics 16, 673-685; Mavko, G., T. Mukerji, and J. Dvorkin, 1998, The Rock Physics Handbook: Tools for seismic analysis in porous media: Cambridge University Press. Wood, A. W., 1955, A Textbook of Sound, The MacMillan Co., New York, 360 pp. Hill, R., 1963, Elastic properties of reinforced solids: some theoretical principles. J. Mech. Phys. Solids, 11, 357-372. Hill, R., 1952, The elastic behavior of crystalline aggregates. Proc. Physical Soc., London, A65, 349-354. J. Toms, T.M. Mueller, B. Gurevich, 2007 Seismic attenuation in porous rocks with random patchy saturation. Geophysical Prospecting, 55, 671-678.

Smoking cessation during alcohol treatment: a randomized trial of combination nicotine patch plus nicotine gum.

PubMed

Cooney, Ned L; Cooney, Judith L; Perry, Bridget L; Carbone, Michael; Cohen, Emily H; Steinberg, Howard R; Pilkey, David T; Sevarino, Kevin; Oncken, Cheryl A; Litt, Mark D

2009-09-01

The primary aim was to compare the efficacy of smoking cessation treatment using a combination of active nicotine patch plus active nicotine gum versus therapy consisting of active nicotine patch plus placebo gum in a sample of alcohol-dependent tobacco smokers in an early phase of out-patient alcohol treatment. A secondary aim was to determine whether or not there were any carry-over effects of combination nicotine replacement on drinking outcomes. Small-scale randomized double-blind placebo-controlled clinical trial with 1-year smoking and drinking outcome assessment. Two out-patient substance abuse clinics provided a treatment platform of behavioral alcohol and smoking treatment delivered in 3 months of weekly sessions followed by three monthly booster sessions. Participants were 96 men and women with a diagnosis of alcohol abuse or dependence and smoking 15 or more cigarettes per day. All participants received open-label transdermal nicotine patches and were randomized to receive either 2 mg nicotine gum or placebo gum under double-blind conditions. Analysis of 1-year follow-up data revealed that patients receiving nicotine patch plus active gum had better smoking outcomes than those receiving patch plus placebo gum on measures of time to smoking relapse and prolonged abstinence at 12 months. Alcohol outcomes were not significantly different across medication conditions. Results of this study were consistent with results of larger trials of smokers without alcohol problems, showing that combination therapy (nicotine patch plus gum) is more effective than monotherapy (nicotine patch) for smoking cessation.

High-throughput electrophysiological assays for voltage gated ion channels using SyncroPatch 768PE.

PubMed

Li, Tianbo; Lu, Gang; Chiang, Eugene Y; Chernov-Rogan, Tania; Grogan, Jane L; Chen, Jun

2017-01-01

Ion channels regulate a variety of physiological processes and represent an important class of drug target. Among the many methods of studying ion channel function, patch clamp electrophysiology is considered the gold standard by providing the ultimate precision and flexibility. However, its utility in ion channel drug discovery is impeded by low throughput. Additionally, characterization of endogenous ion channels in primary cells remains technical challenging. In recent years, many automated patch clamp (APC) platforms have been developed to overcome these challenges, albeit with varying throughput, data quality and success rate. In this study, we utilized SyncroPatch 768PE, one of the latest generation APC platforms which conducts parallel recording from two-384 modules with giga-seal data quality, to push these 2 boundaries. By optimizing various cell patching parameters and a two-step voltage protocol, we developed a high throughput APC assay for the voltage-gated sodium channel Nav1.7. By testing a group of Nav1.7 reference compounds' IC50, this assay was proved to be highly consistent with manual patch clamp (R > 0.9). In a pilot screening of 10,000 compounds, the success rate, defined by > 500 MΩ seal resistance and >500 pA peak current, was 79%. The assay was robust with daily throughput ~ 6,000 data points and Z' factor 0.72. Using the same platform, we also successfully recorded endogenous voltage-gated potassium channel Kv1.3 in primary T cells. Together, our data suggest that SyncroPatch 768PE provides a powerful platform for ion channel research and drug discovery.

Single K ATP channel opening in response to action potential firing in mouse dentate granule neurons.

PubMed

Tanner, Geoffrey R; Lutas, Andrew; Martínez-François, Juan Ramón; Yellen, Gary

2011-06-08

ATP-sensitive potassium channels (K(ATP) channels) are important sensors of cellular metabolic state that link metabolism and excitability in neuroendocrine cells, but their role in nonglucosensing central neurons is less well understood. To examine a possible role for K(ATP) channels in modulating excitability in hippocampal circuits, we recorded the activity of single K(ATP) channels in cell-attached patches of granule cells in the mouse dentate gyrus during bursts of action potentials generated by antidromic stimulation of the mossy fibers. Ensemble averages of the open probability (p(open)) of single K(ATP) channels over repeated trials of stimulated spike activity showed a transient increase in p(open) in response to action potential firing. Channel currents were identified as K(ATP) channels through blockade with glibenclamide and by comparison with recordings from Kir6.2 knock-out mice. The transient elevation in K(ATP) p(open) may arise from submembrane ATP depletion by the Na(+)-K(+) ATPase, as the pump blocker strophanthidin reduced the magnitude of the elevation. Both the steady-state and stimulus-elevated p(open) of the recorded channels were higher in the presence of the ketone body R-β-hydroxybutyrate, consistent with earlier findings that ketone bodies can affect K(ATP) activity. Using perforated-patch recording, we also found that K(ATP) channels contribute to the slow afterhyperpolarization following an evoked burst of action potentials. We propose that activity-dependent opening of K(ATP) channels may help granule cells act as a seizure gate in the hippocampus and that ketone-body-mediated augmentation of the activity-dependent opening could in part explain the effect of the ketogenic diet in reducing epileptic seizures.

Can optical recordings of membrane potential be used to screen for drug-induced action potential prolongation in single cardiac myocytes?

PubMed

Hardy, M E L; Lawrence, C L; Standen, N B; Rodrigo, G C

2006-01-01

Potential-sensitive dyes have primarily been used to optically record action potentials (APs) in whole heart tissue. Using these dyes to record drug-induced changes in AP morphology of isolated cardiac myocytes could provide an opportunity to develop medium throughout assays for the pharmaceutical industry. Ideally, this requires that the dye has a consistent and rapid response to membrane potential, is insensitive to movement, and does not itself affect AP morphology. We recorded the AP from isolated adult guinea-pig ventricular myocytes optically using di-8-ANEPPS in a single-excitation dual-emission ratiometric system, either separately in electrically field stimulated myocytes, or simultaneously with an electrical AP recorded with a patch electrode in the whole-cell bridge mode. The ratio of di-8-ANEPPS fluorescence signal was calibrated against membrane potential using a switch-clamp to voltage clamp the myocyte. Our data show that the ratio of the optical signals emitted at 560/620 nm is linearly related to voltage over the voltage range of an AP, producing a change in ratio of 7.5% per 100 mV, is unaffected by cell movement and is identical to the AP recorded simultaneously with a patch electrode. However, the APD90 recorded optically in myocytes loaded with di-8-ANEPPS was significantly longer than in unloaded myocytes recorded with a patch electrode (355.6+/-13.5 vs. 296.2+/-16.2 ms; p<0.01). Despite this effect, the apparent IC50 for cisapride, which prolongs the AP by blocking IKr, was not significantly different whether determined optically or with a patch electrode (91+/-46 vs. 81+/-20 nM). These data show that the optical AP recorded ratiometrically using di-8-ANEPPS from a single ventricular myocyte accurately follows the action potential morphology. This technique can be used to estimate the AP prolonging effects of a compound, although di-8-ANEPPS itself prolongs APD90. Optical dyes require less technical skills and are less invasive than conventional electrophysiological techniques and, when coupled to ventricular myocytes, decreases animal usage and facilitates higher throughput assays.

Determination of apparent quantum yield spectra of DMS photo-degradation in an in situ iron-induced Northeast Pacific Ocean bloom

NASA Astrophysics Data System (ADS)

Bouillon, René-Christian; Miller, William L.

2004-03-01

The wavelength dependence of the photochemical removal efficiency for DMS was studied for samples from an iron-induced bloom in the Northeastern Pacific Ocean. In July 2002, a 64 km2 patch of ocean was iron-fertilized near Ocean Station Papa (50°12'N 144°45'W). Only small changes in pseudo-first-order apparent quantum yield (AQY*DMS(λ)) were observed outside the iron-patch. However, inside the patch, AQY*DMS(λ) decreased considerably over the two weeks following the initial iron injection. A positive strong correlation was found between pseudo-first-order apparent quantum yield determined at 330 nm (AQY*DMS(330 nm)) and NO3- concentrations. We propose that NO3--photolysis has a substantial influence on DMS photo-degradation rates in oceanic waters. This finding demonstrates that in addition to control DMS production, marine phytoplankton could indirectly influence the DMS photochemical loss rate via its control on NO3- distribution.

Visualisation of flow patterns in straight and C-shape thermosyphons

NASA Astrophysics Data System (ADS)

Ong, K. S.; Tshai, K. H.; Firwana, A.

2017-04-01

A heat pipe is a passive heat transfer device capable of transferring a large quantity of heat effectively and efficiently over a long distance and with a small temperature difference between the heat source and heat sink. A heat pipe consists of a metal pipe initially vacuumed and then filled with a small quantity of fluid inside. The pipe is separated into a heating (evaporator) section and a cooling (condenser) section by an adiabatic section. In a run-around-coil heating, ventilation and air conditioning system, a wrap-around heat pipe heat exchanger could be employed to increase dehumidification and to reduce cooling costs. The thermal performance of a thermosyphon is dependent upon type of fill liquid, fill ratio, power input, pipe inclination and pipe dimensions. The boiling and condensation processes that occur inside a thermosyphon are quite complex. During operation, dry-out, burn-out or boiling limit, entrainment or flooding limit and geysering occur. These phenomena would lead to non-uniform axial wall temperature distribution in the pipe, or worse still, ineffective operation. In order to have a better understanding of the internal heat transfer phenomena, a visual study using transparent glass tubes and high speed camera recording of the internal flow patterns would be most helpful. This paper reports on an experimental investigation conducted to visualise the flow patterns in straight and C-shape thermosyphons. The pictures recorded enabled the internal flow boiling and condensation pattern occurring inside a straight and a C-shape thermosyphon to be observed. The thermosyphons were fabricated from 10 mm O/D × 8 mm I/D × 300 mm long glass tubes and filled with water with fill ratios from 0.5 - 1.5. The evaporator sections of the thermosyphons were immersed into a hot water tank that was electrically heated from cold at ambient temperature till boiling. Cooling of the condenser section was achieved using a fan. Preliminary results showed that dry-out occurred earlier at lower evaporator temperatures with small fill ratios. Further investigations to determine saturation and thermosyphon wall temperatures with various fill liquids and at different fill ratios, inclinations and pipe sizes are necessary with a more sophisticated video recording system.

Testing optimal foraging theory in a penguin-krill system.

PubMed

Watanabe, Yuuki Y; Ito, Motohiro; Takahashi, Akinori

2014-03-22

Food is heterogeneously distributed in nature, and understanding how animals search for and exploit food patches is a fundamental challenge in ecology. The classic marginal value theorem (MVT) formulates optimal patch residence time in response to patch quality. The MVT was generally proved in controlled animal experiments; however, owing to the technical difficulties in recording foraging behaviour in the wild, it has been inadequately examined in natural predator-prey systems, especially those in the three-dimensional marine environment. Using animal-borne accelerometers and video cameras, we collected a rare dataset in which the behaviour of a marine predator (penguin) was recorded simultaneously with the capture timings of mobile, patchily distributed prey (krill). We provide qualitative support for the MVT by showing that (i) krill capture rate diminished with time in each dive, as assumed in the MVT, and (ii) dive duration (or patch residence time, controlled for dive depth) increased with short-term, dive-scale krill capture rate, but decreased with long-term, bout-scale krill capture rate, as predicted from the MVT. Our results demonstrate that a single environmental factor (i.e. patch quality) can have opposite effects on animal behaviour depending on the time scale, emphasizing the importance of multi-scale approaches in understanding complex foraging strategies.

Maintaining social cohesion is a more important determinant of patch residence time than maximizing food intake rate in a group-living primate, Japanese macaque (Macaca fuscata).

PubMed

Kazahari, Nobuko

2014-04-01

Animals have been assumed to employ an optimal foraging strategy (e.g., rate-maximizing strategy). In patchy food environments, intake rate within patches is positively correlated with patch quality, and declines as patches are depleted through consumption. This causes patch-leaving and determines patch residence time. In group-foraging situations, patch residence times are also affected by patch sharing. Optimal patch models for groups predict that patch residence times decrease as the number of co-feeding animals increases because of accelerated patch depletion. However, group members often depart patches without patch depletion, and their patch residence time deviates from patch models. It has been pointed out that patch residence time is also influenced by maintaining social proximity with others among group-living animals. In this study, the effects of maintaining social cohesion and that of rate-maximizing strategy on patch residence time were examined in Japanese macaques (Macaca fuscata). I hypothesized that foragers give up patches to remain in the proximity of their troop members. On the other hand, foragers may stay for a relatively long period when they do not have to abandon patches to follow the troop. In this study, intake rate and foraging effort (i.e., movement) did not change during patch residency. Macaques maintained their intake rate with only a little foraging effort. Therefore, the patches were assumed to be undepleted during patch residency. Further, patch residence time was affected by patch-leaving to maintain social proximity, but not by the intake rate. Macaques tended to stay in patches for short periods when they needed to give up patches for social proximity, and remained for long periods when they did not need to leave to keep social proximity. Patch-leaving and patch residence time that prioritize the maintenance of social cohesion may be a behavioral pattern in group-living primates.

Acetylcholine-evoked currents in cultured neurones dissociated from rat parasympathetic cardiac ganglia.

PubMed Central

Fieber, L A; Adams, D J

1991-01-01

1. The properties of acetylcholine (ACh)-activated ion channels of parasympathetic neurones from neonatal rat cardiac ganglia grown in tissue culture were examined using patch clamp recording techniques. Membrane currents evoked by ACh were mimicked by nicotine, attenuated by neuronal bungarotoxin, and unaffected by atropine, suggesting that the ACh-induced currents are mediated by nicotinic receptor activation. 2. The current-voltage (I-V) relationship for whole-cell ACh-evoked currents exhibited strong inward rectification and a reversal (zero current) potential of -3 mV (NaCl outside, CsCl inside). The rectification was not alleviated by changing the main permeant cation or by removal of divalent cations from the intracellular or extracellular solutions. Unitary ACh-activated currents exhibited a linear I-V relationship with slope conductances of 32 pS in cell-attached membrane patches and 38 pS in excised membrane patches with symmetrical CsCl solutions. 3. Acetylcholine-induced currents were reversibly inhibited in a dose-dependent manner by the ganglionic antagonists, mecamylamine (Kd = 37 nM) and hexamethonium (IC50 approximately 1 microM), as well as by the neuromuscular relaxant, d-tubocurarine (Kd = 3 microM). Inhibition of ACh-evoked currents by hexamethonium could not be described by a simple blocking model for drug-receptor interaction. 4. The amplitude of the ionic current through the open channel was dependent on the extracellular Na+ concentration. The direction of the shift in reversal potential upon replacement of NaCl by mannitol indicates that the neuronal nicotinic receptor channel is cation selective and the magnitude suggests a high cation to anion permeability ratio. The cation permeability (PX/PNa) followed the ionic selectivity sequence Cs+ (1.06) greater than Na+ (1.0) greater than Ca2+ (0.93). Anion substitution experiments showed a relative anion permeability, PCl/PNa less than or equal to 0.05. 5. The nicotinic ACh-activated channels described mediate the responses of postganglionic parasympathetic neurones of the mammalian heart to vagal stimulation. PMID:1708819

Action growth of charged black holes with a single horizon

NASA Astrophysics Data System (ADS)

Cai, Rong-Gen; Sasaki, Misao; Wang, Shao-Jiang

2017-06-01

According to the conjecture "complexity equals action," the complexity of a holographic state is equal to the action of a Wheeler-DeWitt (WDW) patch of black holes in anti-de Sitter space. In this paper we calculate the action growth of charged black holes with a single horizon, paying attention to the contribution from a spacelike singularity inside the horizon. We consider two kinds of such charged black holes: one is a charged dilaton black hole, and the other is a Born-Infeld black hole with β2Q2<1 /4 . In both cases, although an electric charge appears in the black hole solutions, the inner horizon is absent; instead a spacelike singularity appears inside the horizon. We find that the action growth of the WDW patch of the charged black hole is finite and satisfies the Lloyd bound. As a check, we also calculate the action growth of a charged black hole with a phantom Maxwell field. In this case, although the contributions from the bulk integral and the spacelike singularity are individually divergent, these two divergences just cancel each other and a finite action growth is obtained. But in this case, the Lloyd bound is violated as expected.

Susceptibility of ATP-sensitive K+ channels to cell stress through mediation of phosphoinositides as examined by photoirradiation

PubMed Central

Fan, Zheng; Neff, Robert A

2000-01-01

Cell stress is implicated in a number of pathological states of metabolism, such as ischaemia, reperfusion and apoptosis in heart, neurons and other tissues. While it is known that the ATP-sensitive K+ (KATP) channel plays a role during metabolic abnormality, little information is available about the direct response of this channel to cell stress. Using photoirradiation stimulation, we studied the effects of cell stress on both native and cloned KATP channels. Single KATP channel currents were recorded from cell-attached and inside-out patches of rat ventricular myocytes and COS-1 cells coexpressing SUR2 and Kir6.2. KATP channel activity increased within < 1 min upon irradiation. The activity resulted from increased maximal open probability and decreased ATP inhibition. The effects remained after the irradiation was stopped. Irradiation also affected the channels formed only by Kir6.2ΔC35. The irradiation-induced activation was comparable to that induced by phosphoinositides. Analysis of phosphatidylinositol composition revealed an elevated phosphatidylinositol bisphosphate level with irradiation. Wortmannin, an inhibitor of phosphatidylinositol kinases, decreased both the irradiation-induced channel activity and the production of phosphatidylinositol bisphosphates. Radical scavengers also reduced the irradiation-induced activation, suggesting a role for free radicals, an immediate product of photoirradiation. We conclude that photoirradiation can modify the single-channel properties of KATP, which appears to be mediated by phosphoinositides. Our study suggests that cellular stress may be linked with KATP channels, and we offer a putative mechanism for such a linkage. PMID:11118500

Regulation of murine cystic fibrosis transmembrane conductance regulator Cl− channels expressed in Chinese hamster ovary cells

PubMed Central

Lansdell, K A; Kidd, J F; Delaney, S J; Wainwright, B J; Sheppard, D N

1998-01-01

We investigated the effect of protein kinases and phosphatases on murine cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channels, expressed in Chinese hamster ovary (CHO) cells, using iodide efflux and the excised inside-out configuration of the patch-clamp technique.The protein kinase C (PKC) activator, phorbol dibutyrate, enhanced cAMP-stimulated iodide efflux. However, PKC did not augment the single-channel activity of either human or murine CFTR Cl− channels that had previously been activated by protein kinase A.Fluoride, a non-specific inhibitor of protein phosphatases, stimulated both human and murine CFTR Cl− channels. However, calyculin A, a potent inhibitor of protein phosphatases 1 and 2A, did not enhance cAMP-stimulated iodide efflux.The alkaline phosphatase inhibitor, (−)-bromotetramisole augmented cAMP-stimulated iodide efflux and, by itself, stimulated a larger efflux than that evoked by cAMP agonists. However, (+)-bromotetramisole, the inactive enantiomer, had the same effect. For murine CFTR, neither enantiomer enhanced single-channel activity. In contrast, both enantiomers increased the open probability (Po) of human CFTR, suggesting that bromotetramisole may promote the opening of human CFTR.As murine CFTR had a low Po and was refractory to stimulation by activators of human CFTR, we investigated whether murine CFTR may open to a subconductance state. When single-channel records were filtered at 50 Hz, a very small subconductance state of murine CFTR was observed that had a Po greater than that of human CFTR. The occupancy of this subconductance state may explain the differences in channel regulation observed between human and murine CFTR. PMID:9769419

Regulation of neuronal excitability by interaction of fragile X mental retardation protein with slack potassium channels.

PubMed

Zhang, Yalan; Brown, Maile R; Hyland, Callen; Chen, Yi; Kronengold, Jack; Fleming, Matthew R; Kohn, Andrea B; Moroz, Leonid L; Kaczmarek, Leonard K

2012-10-31

Loss of the RNA-binding protein fragile X mental retardation protein (FMRP) represents the most common form of inherited intellectual disability. Studies with heterologous expression systems indicate that FMRP interacts directly with Slack Na(+)-activated K(+) channels (K(Na)), producing an enhancement of channel activity. We have now used Aplysia bag cell (BC) neurons, which regulate reproductive behaviors, to examine the effects of Slack and FMRP on excitability. FMRP and Slack immunoreactivity were colocalized at the periphery of isolated BC neurons, and the two proteins could be reciprocally coimmunoprecipitated. Intracellular injection of FMRP lacking its mRNA binding domain rapidly induced a biphasic outward current, with an early transient tetrodotoxin-sensitive component followed by a slowly activating sustained component. The properties of this current matched that of the native Slack potassium current, which was identified using an siRNA approach. Addition of FMRP to inside-out patches containing native Aplysia Slack channels increased channel opening and, in current-clamp recordings, produced narrowing of action potentials. Suppression of Slack expression did not alter the ability of BC neurons to undergo a characteristic prolonged discharge in response to synaptic stimulation, but prevented recovery from a prolonged inhibitory period that normally follows the discharge. Recovery from the inhibited period was also inhibited by the protein synthesis inhibitor anisomycin. Our studies indicate that, in BC neurons, Slack channels are required for prolonged changes in neuronal excitability that require new protein synthesis, and raise the possibility that channel-FMRP interactions may link changes in neuronal firing to changes in protein translation.

MS lesion segmentation using a multi-channel patch-based approach with spatial consistency

NASA Astrophysics Data System (ADS)

Mechrez, Roey; Goldberger, Jacob; Greenspan, Hayit

2015-03-01

This paper presents an automatic method for segmentation of Multiple Sclerosis (MS) in Magnetic Resonance Images (MRI) of the brain. The approach is based on similarities between multi-channel patches (T1, T2 and FLAIR). An MS lesion patch database is built using training images for which the label maps are known. For each patch in the testing image, k similar patches are retrieved from the database. The matching labels for these k patches are then combined to produce an initial segmentation map for the test case. Finally a novel iterative patch-based label refinement process based on the initial segmentation map is performed to ensure spatial consistency of the detected lesions. A leave-one-out evaluation is done for each testing image in the MS lesion segmentation challenge of MICCAI 2008. Results are shown to compete with the state-of-the-art methods on the MICCAI 2008 challenge.

Blood patch rates after lumbar puncture with Whitacre versus Quincke 22- and 20-gauge spinal needles.

PubMed

Hatfield, Malcolm K; Handrich, Stephen J; Willis, Jeffrey A; Beres, Robert A; Zaleski, George X

2008-06-01

The objective of our study was to compare the incidence of blood patch as the best objective indicator of postdural puncture headache after elective fluoroscopic lumbar puncture with the use of a 22-gauge Whitacre (pencil point) needle versus standard 22- and 20-gauge Quincke (bevel-tip) needles and to determine the best level of puncture. The records of 724 consecutive patients who were referred to St. Mary's Medical Center department of radiology for fluoroscopic lumbar puncture from January 2003 through April 2007 were retrospectively reviewed. Emergency requests (191) were discarded along with those for patients with clinical signs of pseudotumor cerebri (21), normal pressure hydrocephalus (3), and failed attempts (4). The collective total was 505 elective lumbar punctures. The blood patch rate for the 22-gauge Whitacre needle was 4.2%. The result for the 22-gauge Quincke point needle was 15.1% whereas that for the 20-gauge Quincke point needle was 29.6%. In addition, the level of puncture showed a blood patch rate that increased as the level of lumbar puncture lowered. The highest level of lumbar puncture was L1-L2 with the lowest recorded level being L5-S1. The Whitacre needle is associated with a significantly lower incidence of blood patch rate after lumbar puncture. The highest level of puncture (L1-L2) also provides the lowest level of blood patch rate.

Remote fluorescence lifetime inspection of hermeticity of packaged food containers

NASA Astrophysics Data System (ADS)

Mendoza, Edgar A.; Kempen, Cornelia; Sun, Sunjian; Esterkin, Yan

2014-09-01

This paper describes recent progress towards the development of a remote "frequency-domain" fluorescence lifetime (SeePhase™) monitor used for the real time hermetic seal leak inspection of packaged food containers. A multitude of food goods, meets, vegetables, and beverages are typically packaged within an inert environment to reduce the risk of bacteria growth and increase the storage life of the food product. The SeePhase™ system uses a multi-parameter oxygen, carbon dioxide, and moisture sensitive patch that is placed within the hermetic sealed food package. Upon the presence of gases oxygen, carbon dioxide, or moisture inside the hermetic sealed food package, the sensor patch produces a fluorescence lifetime signature characteristic of a hermetic seal leak damage of the package.

Fabrication of tissue engineered tympanic membrane patches using computer-aided design and injection molding.

PubMed

Hott, Morgan E; Megerian, Cliff A; Beane, Rich; Bonassar, Lawrence J

2004-07-01

The goal of the current study was to use computer-aided design and injection molding technologies to tissue engineer precisely shaped cartilage in the shape of butterfly tympanic membrane patches out of chondrocyte-seeded calcium alginate gels. Molds were designed on SolidWorks 2000 and built out of acrylonitrile butadiene styrene (ABS) using fused deposition modeling (FDM). Tympanic membrane patches were fabricated using bovine articular chondrocytes seeded at 50 x 10 cells/mL in 2% calcium alginate gels. Molded patches were cultured in vitro for up to 10 weeks and assessed biochemically, morphologically, and histologically. Unmolded patches demonstrated outstanding dimensional fidelity, with a volumetric precision of at least 3 microL, and maintained their shape well for up to 10 weeks of in vitro culture. Glycosaminoglycan and collagen content increased steadily over 10 weeks in culture, demonstrating continual deposition of new extracellular matrix consistent with new tissue development. The use of computer-aided design and injection molding technologies allows for the fabrication of very small, precisely shaped chondrocyte-seeded calcium alginate structures that faithfully maintain their shape during in vitro culture. In vitro fabrication of tympanic membrane patches with a precisely controlled geometry may have the potential to provide a minimally invasive alternative to traditional methods for the repair of chronic tympanic membrane perforations.

Age-related changes in the anatomical characteristics of Peyer's patches in small intestine of Bactrian camels (Camelus bactrianus).

PubMed

Qi, Shan-Shan; Wang, Wen-Hui; Gao, Qiang; Xu, Xiao-Hong; He, Wan-Hong; Zhaxi, Ying-Pai; Tai, Li-Feng

2011-08-01

The distribution, size, and appearance of Peyer's patches vary according to species. In order to determine the anatomical characteristics of Peyer's patches in small intestine of Bactrian camel, and age-related changes in the number of Peyer's patches, 40 Bactrian camels of the following four age groups were studied: young (0.5-2 years), pubertal (3-5 years), middle-aged (6-16 years), and old (17-20 years). The exact number of Peyer's patches was recorded, and the appearance of Peyer's patches was described in detail. The results indicated that Peyer's patches of Bactrian camels not only have a particular anatomical location and distinct appearance but also change with age. They were distributed in the whole small intestine and there were four distinct types of Peyer's patches: nodular, faviform, cup-shaped, and cystic form Peyer's patches. However, the nodular and cystic form Peyer's patches are specific to Bactrian camel, which have not been found in other animals including Dromedary camel. In addition, the distribution density of Peyer's patches in ileum was the maximum, then was jejunum and duodenum. Further statistical analysis showed that the number of Peyer's patches was altered with age. The number peaked in 5-year-old camels and declined subsequently with age. However, there was little change in the size of Peyer's patches in different age groups; no age-related macroscopic variations in the shape or size of the Peyer's patches were found. Results obtained from this study provide the basic information to further study on the gastrointestinal mucosal immunity of Bactrian camel.

Distribution and Function of HCN Channels in the Apical Dendritic Tuft of Neocortical Pyramidal Neurons

PubMed Central

Harnett, Mark T.; Magee, Jeffrey C.

2015-01-01

The apical tuft is the most remote area of the dendritic tree of neocortical pyramidal neurons. Despite its distal location, the apical dendritic tuft of layer 5 pyramidal neurons receives substantial excitatory synaptic drive and actively processes corticocortical input during behavior. The properties of the voltage-activated ion channels that regulate synaptic integration in tuft dendrites have, however, not been thoroughly investigated. Here, we use electrophysiological and optical approaches to examine the subcellular distribution and function of hyperpolarization-activated cyclic nucleotide-gated nonselective cation (HCN) channels in rat layer 5B pyramidal neurons. Outside-out patch recordings demonstrated that the amplitude and properties of ensemble HCN channel activity were uniform in patches excised from distal apical dendritic trunk and tuft sites. Simultaneous apical dendritic tuft and trunk whole-cell current-clamp recordings revealed that the pharmacological blockade of HCN channels decreased voltage compartmentalization and enhanced the generation and spread of apical dendritic tuft and trunk regenerative activity. Furthermore, multisite two-photon glutamate uncaging demonstrated that HCN channels control the amplitude and duration of synaptically evoked regenerative activity in the distal apical dendritic tuft. In contrast, at proximal apical dendritic trunk and somatic recording sites, the blockade of HCN channels decreased excitability. Dynamic-clamp experiments revealed that these compartment-specific actions of HCN channels were heavily influenced by the local and distributed impact of the high density of HCN channels in the distal apical dendritic arbor. The properties and subcellular distribution pattern of HCN channels are therefore tuned to regulate the interaction between integration compartments in layer 5B pyramidal neurons. PMID:25609619

Distributions-per-level: a means of testing level detectors and models of patch-clamp data.

PubMed

Schröder, I; Huth, T; Suitchmezian, V; Jarosik, J; Schnell, S; Hansen, U P

2004-01-01

Level or jump detectors generate the reconstructed time series from a noisy record of patch-clamp current. The reconstructed time series is used to create dwell-time histograms for the kinetic analysis of the Markov model of the investigated ion channel. It is shown here that some additional lines in the software of such a detector can provide a powerful new means of patch-clamp analysis. For each current level that can be recognized by the detector, an array is declared. The new software assigns every data point of the original time series to the array that belongs to the actual state of the detector. From the data sets in these arrays distributions-per-level are generated. Simulated and experimental time series analyzed by Hinkley detectors are used to demonstrate the benefits of these distributions-per-level. First, they can serve as a test of the reliability of jump and level detectors. Second, they can reveal beta distributions as resulting from fast gating that would usually be hidden in the overall amplitude histogram. Probably the most valuable feature is that the malfunctions of the Hinkley detectors turn out to depend on the Markov model of the ion channel. Thus, the errors revealed by the distributions-per-level can be used to distinguish between different putative Markov models of the measured time series.

Multi-neuron intracellular recording in vivo via interacting autopatching robots

PubMed Central

Holst, Gregory L; Singer, Annabelle C; Han, Xue; Brown, Emery N

2018-01-01

The activities of groups of neurons in a circuit or brain region are important for neuronal computations that contribute to behaviors and disease states. Traditional extracellular recordings have been powerful and scalable, but much less is known about the intracellular processes that lead to spiking activity. We present a robotic system, the multipatcher, capable of automatically obtaining blind whole-cell patch clamp recordings from multiple neurons simultaneously. The multipatcher significantly extends automated patch clamping, or 'autopatching’, to guide four interacting electrodes in a coordinated fashion, avoiding mechanical coupling in the brain. We demonstrate its performance in the cortex of anesthetized and awake mice. A multipatcher with four electrodes took an average of 10 min to obtain dual or triple recordings in 29% of trials in anesthetized mice, and in 18% of the trials in awake mice, thus illustrating practical yield and throughput to obtain multiple, simultaneous whole-cell recordings in vivo. PMID:29297466

Tibiofemoral contact pressures in radial tears of the meniscus treated with all-inside repair, inside-out repair and partial meniscectomy.

PubMed

Zhang, Alan L; Miller, Stephanie L; Coughlin, Dezba G; Lotz, Jeffrey C; Feeley, Brian T

2015-10-01

To test contact pressures in the knee after treatment of a radial meniscus tear with an all-inside meniscal repair technique and compare the results with inside-out repair and partial meniscectomy. Six non-paired cadaveric knees were analyzed with intra-compartment pressures measured at loads of 250 N, 500 N and 1000 N at 0°, eight degrees, 15°, and 30° of knee flexion. Compartmental contact pressures were measured for the intact medial meniscus, radial tear in the posterior horn, all-inside repair using the NovoStitch suture passer device (Ceterix Orthopaedics Inc., Menlo Park, CA), inside-out repair method, and partial meniscectomy. One-way ANOVA was used for statistical analysis. The greatest differences in peak pressures between treatments were observed under 1000 N load at 30° flexion (0.8± (SD) 0.1 MPa (intact meniscus), 0.8± (SD) 0.1 MPa (all-inside), 0.9± (SD) 0.1 MPa (inside-out) and 1.6± (SD) 0.2 MPa (partial meniscectomy)). Treatment with partial meniscectomy resulted in the highest peak pressures compared to all other states (p<0.0001 at each angle). Repair of the radial tear using the all-inside technique as well as the inside-out technique resulted in significantly decreased compartment pressures compared to partial meniscectomies (p<0.0001 at each angle). There were no significant differences between peak pressures in the intact state and after repair with the all-inside or inside-out techniques. An all-inside repair technique using the NovoStitch suture passer can decrease contact pressures for a radial meniscus tear similarly to the inside-out repair technique when compared to partial meniscectomy. This novel arthroscopic suture passer warrants further analysis in the clinical setting as it may be a reliable method for repair of radial meniscal tears through an arthroscopic all-inside technique. Copyright © 2015 Elsevier B.V. All rights reserved.

Departure Mechanisms for Host Search on High-Density Patches by the Meteorus pulchricornis

PubMed Central

Sheng, Sheng; Feng, Sufang; Meng, Ling; Li, Baoping

2014-01-01

Abstract Less attention has been paid to the parasitoid–host system in which the host occurs in considerably high density with a hierarchical patch structure in studies on time allocation strategies of parasitoids. This study used the parasitoid Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae) and the Oriental leafworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) as the parasitoids–host model system to investigate patch-leaving mechanisms as affected by the high-host density, hierarchical patch structure, and foraging behaviors on both former and current patches. The results showed that three out of eight covariates tested had significant effects on the patch-leaving tendency, including the host density, ovipositor insertion, and host rejection on the current patch. The parasitoid paid more visits to the patch with high-density hosts. While the patch with higher host densities decreased the leaving tendency, the spatial distribution of hosts examined had no effect on the leaving tendency. Both oviposition and host rejection decreased the patch-leaving tendency. The variables associated with the former patch, such as the host density and number of ovipositor insertions, however, did not have an effect on the leaving tendency. Our study suggested that M. pulchricornis females may use an incremental mechanism to exploit high-density patches to the fullest. PMID:25502040

Comparison of arthroscopic medial meniscal suture repair techniques: inside-out versus all-inside repair.

PubMed

Choi, Nam-Hong; Kim, Tae-Hyung; Victoroff, Brian N

2009-11-01

There are no reports comparing meniscal healing between inside-out and all-inside repairs using sutures. No difference in healing rate exists between meniscal repairs with inside-out and all-inside suture repair in conjunction with anterior cruciate ligament reconstruction with hamstring tendon. Cohort study; Level of evidence, 2. Forty-eight consecutive patients underwent meniscal repairs of longitudinal tears of the posterior horn of the medial meniscus combined with anterior cruciate ligament reconstructions. All-inside repair was attempted when the tears were located in the red-red zone or the ramp area of the meniscus. If a tear that was in the ramp area or red-red zone extended to the midbody of the meniscus, or if there was a tear in red-white zone, the inside-out repair technique was used. Fourteen patients had all-inside meniscal repairs, and 34 patients had inside-out meniscal repairs with absorbable sutures. Identical postoperative rehabilitation protocols were used. Postoperative evaluations included Lysholm knee scoring scale, Tegner activity levels, Lachman and pivot-shift tests, and KT-1000 arthrometer. Assessment of meniscal status was performed using joint line tenderness, McMurray test, and range of motion. Follow-up magnetic resonance imaging scans were obtained on all patients. Mean follow-up was 35.7 months. No patient had joint line tenderness or reported pain or clicking on McMurray test. There was no significant difference in range of motion between groups. Follow-up magnetic resonance imaging scans demonstrated that 10 (71.4%) menisci were healed and 4 (28.6%) partially healed in the all-inside group; 24 (70.6%) menisci were healed and 10 (29.4%) partially healed in the inside-out group. There was no significant difference in meniscal healing between groups. There were no differences in Lachman test, KT-1000 arthrometer side-to-side differences measurements, Lysholm scores, and Tegner activity scales. There was a significant difference in pivot-shift test between groups (P = .023). There were 2 complications associated with surgery. In the inside-out group, 1 patient required manipulation, and 2 patients had limited motion at final follow-up. Two patients in the inside-out group experienced transient saphenous nerve injury. There was no significant difference in meniscal healing between inside-out and all-inside repair techniques in combination with anterior cruciate ligament reconstructions.

Evaluating the capability of Landsat 8 OLI and SPOT 6 for discriminating invasive alien species in the African Savanna landscape

NASA Astrophysics Data System (ADS)

Kganyago, Mahlatse; Odindi, John; Adjorlolo, Clement; Mhangara, Paidamoyo

2018-05-01

Globally, there is paucity of accurate information on the spatial distribution and patch sizes of Invasive Alien Plants (IAPs) species. Such information is needed to aid optimisation of control mechanisms to prevent further spread of IAPs and minimize their impacts. Recent studies have shown the capability of very high spatial (<1 m) and spectral resolution (<10 nm) data for discriminating vegetation species. However, very high spatial resolution may introduce significant intra-species spectral variability and result in reduced mapping accuracy, while higher spectral resolution data are commonly limited to smaller areas, are costly and computationally expensive. Alternatively, medium and high spatial resolution data are available at low or no cost and have limitedly been evaluated for their potential in determining invasion patterns relevant for invasion ecology and aiding effective IAPs management. In this study medium and high resolution datasets from Landsat Operational Land Imager (OLI) and SPOT 6 sensors respectively, were evaluated for mapping the distribution and patch sizes of IAP, Parthenium hysterophorus in the savannah landscapes of KwaZulu-Natal, South Africa. Support Vector Machines (SVM) classifier was used for classification of both datasets. Results indicated that SPOT 6 had a higher overall accuracy (86%) than OLI (83%) in mapping P. hysterophorus. The study found larger distributions and patch sizes in OLI than in SPOT 6 as a result of possible P. hysterophorus expansion due to temporal differences between images and coarser pixels were insufficient to delineate gaps inside larger patches. On the other hand, SPOT 6 showed better capabilities of delineating gaps and boundaries of patches, hence had better estimates of distribution and patch sizes. Overall, the study showed that OLI may be suitable for mapping well-established patches for the purpose of large scale monitoring, while SPOT 6 can be used for mapping small patches and prioritising them for eradication to prevent further spread at a landscape scale.

Can robots patch-clamp as well as humans? Characterization of a novel sodium channel mutation

PubMed Central

Estacion, M; Choi, J S; Eastman, E M; Lin, Z; Li, Y; Tyrrell, L; Yang, Y; Dib-Hajj, S D; Waxman, S G

2010-01-01

Ion channel missense mutations cause disorders of excitability by changing channel biophysical properties. As an increasing number of new naturally occurring mutations have been identified, and the number of other mutations produced by molecular approaches such as in situ mutagenesis has increased, the need for functional analysis by patch-clamp has become rate limiting. Here we compare a patch-clamp robot using planar-chip technology with human patch-clamp in a functional assessment of a previously undescribed Nav1.7 sodium channel mutation, S211P, which causes erythromelalgia. This robotic patch-clamp device can increase throughput (the number of cells analysed per day) by 3- to 10-fold. Both modes of analysis show that the mutation hyperpolarizes activation voltage dependence (−8 mV by manual profiling, −11 mV by robotic profiling), alters steady-state fast inactivation so that it requires an additional Boltzmann function for a second fraction of total current (∼20% manual, ∼40% robotic), and enhances slow inactivation (hyperpolarizing shift −15 mV by human, −13 mV robotic). Manual patch-clamping demonstrated slower deactivation and enhanced (∼2-fold) ramp response for the mutant channel while robotic recording did not, possibly due to increased temperature and reduced signal-to-noise ratio on the robotic platform. If robotic profiling is used to screen ion channel mutations, we recommend that each measurement or protocol be validated by initial comparison to manual recording. With this caveat, we suggest that, if results are interpreted cautiously, robotic patch-clamp can be used with supervision and subsequent confirmation from human physiologists to facilitate the initial profiling of a variety of electrophysiological parameters of ion channel mutations. PMID:20123784

Robotic multi-well planar patch-clamp for native and primary mammalian cells

PubMed Central

Milligan, Carol J; Li, Jing; Sukumar, Piruthivi; Majeed, Yasser; Dallas, Mark L; English, Anne; Emery, Paul; Porter, Karen E; Smith, Andrew M; McFadzean, Ian; Beccano-Kelly, Dayne; Bahnasi, Yahya; Cheong, Alex; Naylor, Jacqueline; Zeng, Fanning; Liu, Xing; Gamper, Nikita; Jiang, Lin-Hua; Pearson, Hugh A; Peers, Chris; Robertson, Brian; Beech, David J

2009-01-01

Multi-well robotic planar patch-clamp has become common in drug development and safety programmes because it enables efficient and systematic testing of compounds against ion channels during voltage-clamp. It has not, however, been adopted significantly in other important areas of ion channel research, where conventional patch-clamp remains the favoured method. Here we show the wider potential of the multi-well approach with the capability for efficient intracellular solution exchange, describing protocols and success rates for recording from a range of native and primary mammalian cells derived from blood vessels, arthritic joints, and the immune and central nervous systems. The protocol involves preparing a suspension of single cells to be dispensed robotically into 4-8 microfluidic chambers each containing a glass chip with a small aperture. Under automated control, giga-seals and whole-cell access are achieved followed by pre-programmed routines of voltage paradigms and fast extracellular or intracellular solution exchange. Recording from 48 chambers usually takes 1-6 hr depending on the experimental design and yields 16-33 cell recordings. PMID:19197268

Assessing interventions to increase compliance to patching treatment in children with amblyopia: a systematic review and meta-analysis.

PubMed

Dean, Sarah Elizabeth; Povey, Rachel Clare; Reeves, Jessica

2016-02-01

Amblyopia is the most common condition affecting visual acuity in childhood. Left untreated it will not resolve itself, leading to increased risk of blindness. Occluding the good eye with a patch is a highly effective treatment if carried out before age 7 years but compliance is a major problem. This systematic review addresses the question: How effective are existing interventions at increasing compliance to patching treatment in children with amblyopia? Electronic searches were carried out in June 2014 and updated in April 2015 to identify studies reporting primary data on interventions to increase patching compliance. Data screening, extraction and quality ratings were performed independently by two researchers. Nine papers were included. Interventions including an educational element (5 studies) significantly increased patching compliance and had higher quality ratings than interventions that changed aspects of the patching regime (3 studies) or involved supervised occlusion (1 study). Meta-analysis was conducted on four studies and indicated that overall interventions involving an educational element have a significant small effect r=0.249, p<0.001. Interventions to increase patching compliance should include educational elements. High quality research is needed to further assess the effectiveness of specific elements of educational interventions and additional behaviour change techniques. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Design and Fabrication of Graphene Reinforced Polymer Conductive Patch-Based Inset Fed Microstrip Antenna

NASA Astrophysics Data System (ADS)

Deepak, A.; Kannan, P. Muthu; Shankar, P.

This work explores the design and fabrication of graphene reinforced polyvinylidene fluoride (PVDF) patch-based microstrip antenna. Primarily, antenna was designed at 6GHz frequency and simulation results were obtained using Ansoft HFSS tool. Later fabrication of antenna was carried out with graphene-PVDF films as conducting patch deposited on bakelite substrate and copper as ground plane. Graphene-PVDF films were prepared using solvent casting process. The radiation efficiency of fabricated microstrip patch antenna was 48% entailing it to be adapted as a practically functional antenna. Both simulated and the practical results were compared and analyzed.

Building Instructional Quality: "Inside-Out" and "Outside-In" Perspectives on San Diego's School Reform. A Research Report

ERIC Educational Resources Information Center

Darling-Hammond, Linda; Hightower, Amy M.; Husbands, Jennifer L.; LaFors, Jeannette R.; Young, Viki M.; Christopher, Carl

2003-01-01

During the 1990s, a new policy hypothesis focusing on the quality of teaching to provide a high-leverage means for improving student achievement began to gain currency. Based on interview, observation, survey, and record data collected at the state, district, and school levels over a five-year time period, the study offers a look at how the San…

By the Numbers: Expedition 52

NASA Image and Video Library

2017-09-08

Expedition 52, as simple as 1-2-3: the first International Space Station science officer who was also the second woman to serve as a station crewmember has now finished her third long-duration mission…and that’s just for starters. Last week’s crew return to Earth puts Expedition 52 in the record books; we peeked inside and pulled out some of the best numbers to sum up the flight.

Efficiency of electronically monitored amblyopia treatment between 5 and 16 years of age: new insight into declining susceptibility of the visual system.

PubMed

Fronius, Maria; Cirina, Licia; Ackermann, Hanns; Kohnen, Thomas; Diehl, Corinna M

2014-10-01

The notion of a limited, early period of plasticity of the visual system has been challenged by more recent research demonstrating functional enhancement even into adulthood. In amblyopia ("lazy eye") it is still unclear to what extent the reduced effect of treatment after early childhood is due to declining plasticity or lower compliance with prescribed patching. The aim of this study was to determine the dose-response relationship and treatment efficiency from acuity gain and electronically recorded patching dose rates, and to infer from these parameters on a facet of age dependence of functional plasticity related to occlusion for amblyopia. The Occlusion Dose Monitor was used to record occlusion in 27 participants with previously untreated strabismic and/or anisometropic amblyopia aged between 5.4 and 15.8 (mean 9.2) years during 4months of conventional treatment. Group data showed improvement of acuity throughout the age span, but significantly more in patients younger than 7years despite comparable patching dosages. Treatment efficiency declined with age, with the most pronounced effects before the age of 7years. Thus, electronic recording allowed this first quantitative insight into occlusion treatment spanning the age range from within to beyond the conventional age for patching. Though demonstrating improvement in over 7year old patients, it confirmed the importance of early detection and treatment of amblyopia. Treatment efficiency is presented as a tool extending insight into age-dependent functional plasticity of the visual system, and providing a basis for comparisons of effects of patching vs. emerging alternative treatment approaches for amblyopia. Copyright © 2014 Elsevier Ltd. All rights reserved.

Two-dimensional simulation of holographic data storage medium for multiplexed recording.

PubMed

Toishi, Mitsuru; Takeda, Takahiro; Tanaka, Kenji; Tanaka, Tomiji; Fukumoto, Atsushi; Watanabe, Kenjiro

2008-02-18

In this paper, we propose a new analysis model for photopolymer recording processes that calculate the two-dimensional refractive index distribution of multiplexed holograms. For the simulation of the photopolymer medium, time evolution of monomer diffusion and polymerization need to be calculated simultaneously. The distribution of the refractive index inside the medium is induced by these processes. By evaluating the refractive index pattern on each layer, the diffraction beams from the multiplexed hologram can be read out by beam propagation method (BPM). This is the first paper to determine the diffraction beam from a multiplexed hologram in a simulated photopolymer medium process. We analyze the time response of the multiplexed hologram recording processes in the photopolymer, and estimate the degradation of diffraction efficiency with multiplexed recording. This work can greatly contribute to understanding the process of hologram recording.

Results of patch testing in 10 patients with peristomal dermatitis.

PubMed

Landis, Megan N; Keeling, James H; Yiannias, James A; Richardson, Donna M; Nordberg Linehan, Diane L; Davis, Mark D P

2012-09-01

Peristomal dermatitis is a common problem in patients with ostomies that is a source of considerable morbidity. Irritant contact dermatitis is most common, but allergic contact dermatitis can also occur. Because of the lack of published reports on patch testing for this indication, we undertook a retrospective study of patch testing results in patients with suspected peristomal allergic contact dermatitis. We sought to describe our patch testing experience with patients referred with peristomal dermatitis. This was a retrospective review of medical records of patients with ostomies and peristomal dermatitis who underwent patch testing in the Mayo Clinic Departments of Dermatology in Jacksonville, FL; Rochester, MN; and Scottsdale, AZ, during a 10-year period (2000-2010). Ten patients with peristomal dermatitis were referred for patch testing (6 in Minnesota, 2 in Florida, and 2 in Arizona). Patients were patch tested to the materials used in their stoma devices, to the standard series, and in some cases to supplemental series. All 10 had at least one allergic patch test reaction, most commonly to stoma paste (3 of 10 patients). Retrospective nature of study via chart review is a limitation. Patch testing is a useful tool for identification of allergens in patients with peristomal dermatitis. Copyright © 2011 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.

[Record of epidemiologically important Culicidae in the rural area of Manaus, Amazonas].

PubMed

Barbosa, Maria das Graças Vale; Fé, Nelson Ferreira; Marcião, Alexandre Herculano Ribera; Silva, Ana Paula Thomé da; Monteiro, Wuelton Marcelo; Guerra, Marcus Vinitius de Farias; Guerra, Jorge Augusto de Oliveira

2008-01-01

The biodiversity of the Amazon region includes many species of arthropod vectors in different ecotopes, thus enabling occurrences of diseases like malaria, filariasis and arbovirosis. From August 2001 to July 2002, we gathered culicids from inside homes, from areas surrounding these homes and from forested areas of the São João Community, in the rural zone of Manaus, State of Amazonas. 1240 specimens were collected, belonging to the Culicinae (99%) and Anophelinae (1%) subfamilies, with 50 species. The Culicini tribe clearly predominated, with 904 specimens (72.9%), and the species Culex usquatus (22.6%) and Culex quinquefasciatus (17.7%) were prominent. Out of the total number of culicids, 1,077 (86.9%) were caught in the forests, 101 (8.1%) in the areas surrounding homes and 62 (5%) inside homes. Forests were the ecotope that presented the highest species diversity. The presence of Anopheles darlingi, Anopheles triannulatus, Aedes aegypti, Haemagogus janthinomys and other proven or potential vectors was recorded.

Microfabricated Patch Clamp Electrodes for Improved Ion Channel Protein Measurements

NASA Astrophysics Data System (ADS)

Klemic, James; Klemic, Kathryn; Reed, Mark; Sigworth, Frederick

2002-03-01

Ion channels are trans-membrane proteins that underlie many cell functions including hormone and neurotransmitter release, muscle contraction and cell signaling cascades. Ion channel proteins are commonly characterized via the patch clamp method in which an extruded glass tube containing ionic solution, manipulated by an expert technician, is brought into contact with a living cell to record ionic current through the cell membrane. Microfabricated planar patch electrodes, micromolded in the silicone elastomer poly-dimethylsiloxane (PDMS) from microlithographically patterned structures, have been developed that improve on this method. Microfabrication techniques allow arrays of patch electrodes to be fabricated, increasing the throughput of the measurement technique. Planar patch electrodes readily allow the automation of cell sealing, further increasing throughput. Microfabricated electrode arrays may be readily integrated with microfluidic structures to allow fast, in situ solution exchange. Miniaturization of the electrode geometry should increase both the signal to noise and the bandwidth of the measurement. Microfabricated patch electrode arrays have been fabricated and measurements have been taken.

Space Odyssey Gift Shop

NASA Technical Reports Server (NTRS)

2000-01-01

The Space Odyssey Gift Shop located in StenniSphere at the John C. Stennis Space Center in Hancock County, Miss., offers every visitor the opportunity to go home with 'the right stuff' from his or her StenniSphere visit. The gift shop is located just inside the front doors to StenniSphere and offers a wide range of space-related apparel, memorabilia, toys, books, mission patches and more.

Comparing reliabilities of strip and conventional patch testing.

PubMed

Dickel, Heinrich; Geier, Johannes; Kreft, Burkhard; Pfützner, Wolfgang; Kuss, Oliver

2017-06-01

The standardized protocol for performing the strip patch test has proven to be valid, but evidence on its reliability is still missing. To estimate the parallel-test reliability of the strip patch test as compared with the conventional patch test. In this multicentre, prospective, randomized, investigator-blinded reliability study, 132 subjects were enrolled. Simultaneous duplicate strip and conventional patch tests were performed with the Finn Chambers ® on Scanpor ® tape test system and the patch test preparations nickel sulfate 5% pet., potassium dichromate 0.5% pet., and lanolin alcohol 30% pet. Reliability was estimated by the use of Cohen's kappa coefficient. Parallel-test reliability values of the three standard patch test preparations turned out to be acceptable, with slight advantages for the strip patch test. The differences in reliability were 9% (95%CI: -8% to 26%) for nickel sulfate and 23% (95%CI: -16% to 63%) for potassium dichromate, both favouring the strip patch test. The standardized strip patch test method for the detection of allergic contact sensitization in patients with suspected allergic contact dermatitis is reliable. Its application in routine clinical practice can be recommended, especially if the conventional patch test result is presumably false negative. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

CFTR Cl- channel and CFTR-associated ATP channel: distinct pores regulated by common gates.

PubMed Central

Sugita, M; Yue, Y; Foskett, J K

1998-01-01

The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel that is regulated by phosphorylation of the R domain and ATP hydrolysis at two nucleotide-binding domains (NBDs). It is controversial whether CFTR conducts ATP or whether CFTR might be closely associated with a separate ATP conductance. To characterize ATP channels associated with CFTR, we analyzed Cl- and ATP single channel-currents in excised inside-out membrane patches from MDCK epithelial cells transiently expressing CFTR. With 100 mM ATP in the pipette and 140 mM Cl- in the bath, ATP channels were associated with CFTR Cl- channels in two-thirds of patches that included CFTR. CFTR Cl- channels and CFTR-associated ATP channels had slope conductances of 7.4 pS and 5.2 pS, respectively, and had distinct reversal potentials and sensitivities to channel blockers. CFTR-associated ATP channels exhibited slow gating kinetics that depended on the presence of protein kinase A and cytoplasmic ATP, similar to CFTR Cl- channels. Gating kinetics of the ATP channels as well as the CFTR Cl- channels were similarly affected by non-hydrolyzable ATP analogues and mutations in the CFTR R domain and NBDs. Our results indicate that phosphorylation- and nucleotide-hydrolysis-dependent gating of CFTR is directly involved in gating of an associated ATP channel. However, the permeation pathways for Cl- and ATP are distinct and the ATP conduction pathway is not obligatorily associated with the expression of CFTR. PMID:9463368

Air temperature recordings in infant incubators.

PubMed Central

Aynsley-Green, A; Roberton, N R; Rolfe, P

1975-01-01

Air temperatures were continuously recorded inside four incubators with proportional heating control and six incubators with on/off heating cycles, during routine use. The air temperatures in the former were constant throughout, with a gradient between the roof and above-mattress air temperature not exceeding 1 degree C. In contrast, the recordings from the latter models showed a regular cyclical oscillation, the duration of the cycle varying from 14 to 44 minutes. Each incubator had a characteristic profile. The roof air temperature could vary by as much as 7-1 degrees C and the above-mattress air temperature by as much as 2-6 degrees C during the cycle. The oscillation persisted in the air temperatures recorded inside an open-ended hemicylindrical heat shield when used inside these incubators, but was markedly reduced inside a closed-ended heat shield, Carbon dioxide concentration did not increase significantly inside the latter. Images FIG. 1 FIG. 2 PMID:1147654

Towards a Hybrid Agent-based Model for Mosquito Borne Disease.

PubMed

Mniszewski, S M; Manore, C A; Bryan, C; Del Valle, S Y; Roberts, D

2014-07-01

Agent-based models (ABM) are used to simulate the spread of infectious disease through a population. Detailed human movement, demography, realistic business location networks, and in-host disease progression are available in existing ABMs, such as the Epidemic Simulation System (EpiSimS). These capabilities make possible the exploration of pharmaceutical and non-pharmaceutical mitigation strategies used to inform the public health community. There is a similar need for the spread of mosquito borne pathogens due to the re-emergence of diseases such as chikungunya and dengue fever. A network-patch model for mosquito dynamics has been coupled with EpiSimS. Mosquitoes are represented as a "patch" or "cloud" associated with a location. Each patch has an ordinary differential equation (ODE) mosquito dynamics model and mosquito related parameters relevant to the location characteristics. Activities at each location can have different levels of potential exposure to mosquitoes based on whether they are inside, outside, or somewhere in-between. As a proof of concept, the hybrid network-patch model is used to simulate the spread of chikungunya through Washington, DC. Results are shown for a base case, followed by varying the probability of transmission, mosquito count, and activity exposure. We use visualization to understand the pattern of disease spread.

Stripline feed for a microstrip array of patch elements with teardrop shaped probes

NASA Technical Reports Server (NTRS)

Huang, John (Inventor)

1990-01-01

A circularly polarized microstrip array antenna utilizing a honeycomb substrate made of dielectric material to support on one side the microstrip patch elements in an array, and on the other side a stripline circuit for feeding the patch elements in subarray groups of four with angular orientation and phase for producing circularly polarized radiation, preferably at a 0.degree., 90.degree., 180.degree. and 270.degree. relationship. The probe used for coupling each feed point in the stripline circuit to a microstrip patch element is teardrop shaped in order to introduce capacitance between the coupling probe and the metal sheet of the stripline circuit that serves as an antenna ground plane. The capacitance thus introduced tunes out inductance of the probe. The shape of the teardrop probe is not critical. The probe capacitance required is controlled by the maximum diameter for the teardrop shaped probe, which can be empirically determined for the operating frequency. An aluminum baffle around each subarray blocks out surface waves between subarrays.

Ionic requirements for membrane-glass adhesion and giga seal formation in patch-clamp recording.

PubMed

Priel, Avi; Gil, Ziv; Moy, Vincent T; Magleby, Karl L; Silberberg, Shai D

2007-06-01

Patch-clamp recording has revolutionized the study of ion channels, transporters, and the electrical activity of small cells. Vital to this method is formation of a tight seal between glass recording pipette and cell membrane. To better understand seal formation and improve practical application of this technique, we examine the effects of divalent ions, protons, ionic strength, and membrane proteins on adhesion of membrane to glass and on seal resistance using both patch-clamp recording and atomic force microscopy. We find that H(+), Ca(2+), and Mg(2+) increase adhesion force between glass and membrane (lipid and cellular), decrease the time required to form a tight seal, and increase seal resistance. In the absence of H(+) (10(-10) M) and divalent cations (<10(-8) M), adhesion forces are greatly reduced and tight seals are not formed. H(+) (10(-7) M) promotes seal formation in the absence of divalent cations. A positive correlation between adhesion force and seal formation indicates that high resistance seals are associated with increased adhesion between membrane and glass. A similar ionic dependence of the adhesion of lipid membranes and cell membranes to glass indicates that lipid membranes without proteins are sufficient for the action of ions on adhesion.

The analgesic effect of benzocaine mucoadhesive patches on orthodontic pain caused by elastomeric separators, a preliminary study.

PubMed

Eslamian, Ladan; Borzabadi-Farahani, Ali; Edini, Hosniye Zia; Badiee, Mohammad R; Lynch, Edward; Mortazavi, Alireza

2013-09-01

To study the effect of benzocaine mucoadhesive patches (20%) on orthodontic pain caused by elastomeric separators. A split-mouth design was used in 30 patients (12 female, 18 male, aged 23 ± 3.75 years). They were instructed to apply benzocaine and placebo patches randomly for right or left first permanent molars of maxillary/mandibular arches for 20 min and repeat this procedure every 6 h with a similar type patch. A 10 cm Visual Analogue Scale (VAS) was used for pain perception assessment in patients who were given benzocaine (benzocaine group) or placebo (placebo group) patches. Pain perception (VAS) was recorded immediately after separator placement and after 2, 6, 12, 18, 24, 48 and 72 h. The mean VAS (SD) for the placebo and benzocaine groups were 2.28 (1.08) and 1.63 (0.67), respectively. The pain peaked at 24 h. Significant pain perception differences were observed between groups at 2, 18, 24, 48 and 72 h. Pain perception was not different between genders or jaws investigated (p > 0.05). The Friedman test revealed significant differences in pain perception among various time intervals for benzocaine (χ (2) = 99.84, p = 0.000) and placebo (χ (2) = 102.361, p = 0.000) groups. Significant negative correlations (ρ) were found only between pain perception scores and patient's ages in the placebo group at 18 (-0.438), 24 (-0.526), 48 (-0.565) and 72 h (-0.458). The recorded mean VAS values were relatively low; however, the benzocaine 20% patches significantly reduced the post-separation orthodontic pain.

A study of human recognition rates for foveola-sized image patches selected from initial and final fixations on calibrated natural images

NASA Astrophysics Data System (ADS)

van der Linde, Ian; Rajashekar, Umesh; Cormack, Lawrence K.; Bovik, Alan C.

2005-03-01

Recent years have seen a resurgent interest in eye movements during natural scene viewing. Aspects of eye movements that are driven by low-level image properties are of particular interest due to their applicability to biologically motivated artificial vision and surveillance systems. In this paper, we report an experiment in which we recorded observers" eye movements while they viewed calibrated greyscale images of natural scenes. Immediately after viewing each image, observers were shown a test patch and asked to indicate if they thought it was part of the image they had just seen. The test patch was either randomly selected from a different image from the same database or, unbeknownst to the observer, selected from either the first or last location fixated on the image just viewed. We find that several low-level image properties differed significantly relative to the observers" ability to successfully designate each patch. We also find that the differences between patch statistics for first and last fixations are small compared to the differences between hit and miss responses. The goal of the paper was to, in a non-cognitive natural setting, measure the image properties that facilitate visual memory, additionally observing the role that temporal location (first or last fixation) of the test patch played. We propose that a memorability map of a complex natural scene may be constructed to represent the low-level memorability of local regions in a similar fashion to the familiar saliency map, which records bottom-up fixation attractors.

Departure mechanisms for host search on high-density patches by the Meteorus pulchricornis.

PubMed

Sheng, Sheng; Feng, Sufang; Meng, Ling; Li, Baoping

2014-01-01

Less attention has been paid to the parasitoid-host system in which the host occurs in considerably high density with a hierarchical patch structure in studies on time allocation strategies of parasitoids. This study used the parasitoid Meteorus pulchricornis (Wesmael) (Hymenoptera: Braconidae) and the Oriental leafworm, Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) as the parasitoids-host model system to investigate patch-leaving mechanisms as affected by the high-host density, hierarchical patch structure, and foraging behaviors on both former and current patches. The results showed that three out of eight covariates tested had significant effects on the patch-leaving tendency, including the host density, ovipositor insertion, and host rejection on the current patch. The parasitoid paid more visits to the patch with high-density hosts. While the patch with higher host densities decreased the leaving tendency, the spatial distribution of hosts examined had no effect on the leaving tendency. Both oviposition and host rejection decreased the patch-leaving tendency. The variables associated with the former patch, such as the host density and number of ovipositor insertions, however, did not have an effect on the leaving tendency. Our study suggested that M. pulchricornis females may use an incremental mechanism to exploit high-density patches to the fullest. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

Results of patch testing with lavender oil in Japan.

PubMed

Sugiura, M; Hayakawa, R; Kato, Y; Sugiura, K; Hashimoto, R

2000-09-01

We report the annual results of patch testing with lavender oil for a 9-year period from 1990 to 1998 in Japan. Using Finn Chambers and Scanpor tape, we performed 2-day closed patch testing with lavender oil 20% pet. on the upper back of each patient suspected of having cosmetic contact dermatitis. We compared the frequency of positive patch tests to lavender oil each year with those to other fragrances. We diagnosed contact allergy when patch test reactions were + or <+ at 1 day after removal. The positivity rate of lavender oil was 3.7% (0-13.9%) during the 9-year period from 1990 to 1998. The positivity rate of lavender oil increased suddenly in 1997. Recently, in Japan, there has been a trend for aromatherapy using lavender oil. With this trend, placing dried lavender flowers in pillows, drawers, cabinets, or rooms has become a new fashion. We asked patients who showed a positive reaction to lavender oil about their use of dried lavender flowers. We confirmed the use of dried lavender flowers in 5 cases out of 11 positive cases in 1997 and 8 out of 15 positive cases in 1998. We concluded that the increase in patch test positivity rates to lavender oil in 1997 and 1998 was due to the above fashion, rather than due to fragrances in cosmetic products.

Taking the Bite Out of Vector-Borne Diseases

MedlinePlus

... the 'Bite' Out of Vector-Borne Diseases Inside Life Science View All Articles | Inside Life Science Home Page Taking the 'Bite' Out of Vector- ... Science Solving the Sleeping Sickness 'Mystery' This Inside Life Science article also appears on LiveScience . Learn about related ...

A unique noninvasive approach to monitoring dissolved O2 and CO2 in cell culture.

PubMed

Chatterjee, Madhubanti; Ge, Xudong; Uplekar, Shaunak; Kostov, Yordan; Croucher, Leah; Pilli, Manohar; Rao, Govind

2015-01-01

Although online monitoring of dissolved oxygen (DO) and carbon dioxide (DCO2 ) is highly desirable in bioprocesses, small-scale bioreactors are usually not monitored due to the lack of suitable sensors. Traditional electrochemical sensors are usually not used because they are bulky and invasive. Disposable optical sensors are small and only partially invasive, but there are concerns regarding the toxicity of the patch and the phototoxicity of the illuminating light. Here we present a novel, noninvasive, rate-based technique for monitoring DO and DCO2 in cell cultures. A silicone sampling loop which allowed the diffusion of O2 and CO2 through its wall was inserted inside a bioreactor, and then flushed with N2 until the CO2 and O2 inside the loop were completely removed. The gas inside the loop was then allowed to recirculate through gas impermeable tubing to the O2 and CO2 sensors. We have shown that by measuring the initial diffusion rate we were able to determine the partial pressures of the two gases in the culture. The technique could be readily automated and measurements could be made in minutes. It was tested in demonstration experiments by growing murine hybridoma cells in a T-flask and a spinner-flask at 37°C. The results were comparable to those measured with commercially available fluorescence-based patch sensors. These results show that the rate-based method is an effective way to monitor small-scale cell cultures. This measurement mechanism can be easily built into disposable cell culture vessels for facile use. © 2014 Wiley Periodicals, Inc.

Direct activation of Ca2+ and voltage-gated potassium channels of large conductance by anandamide in endothelial cells does not support the presence of endothelial atypical cannabinoid receptor.

PubMed

Bondarenko, Alexander I; Panasiuk, Olga; Okhai, Iryna; Montecucco, Fabrizio; Brandt, Karim J; Mach, Francois

2017-06-15

Endocannabinoid anandamide induces endothelium-dependent relaxation commonly attributed to stimulation of the G-protein coupled endothelial anandamide receptor. The study addressed the receptor-independent effect of anandamide on large conductance Ca 2+ -dependent K + channels expressed in endothelial cell line EA.hy926. Under resting conditions, 10µM anandamide did not significantly influence the resting membrane potential. In a Ca 2+ -free solution the cells were depolarized by ~10mV. Further administration of 10µM anandamide hyperpolarized the cells by ~8mV. In voltage-clamp mode, anandamide elicited the outwardly rectifying whole-cell current sensitive to paxilline but insensitive to GDPβS, a G-protein inhibitor. Administration of 70µM Mn 2+ , an agent used to promote integrin clustering, reversibly stimulated whole-cell current, but failed to further facilitate the anandamide-stimulated current. In an inside-out configuration, anandamide (0.1-30µM) facilitated single BK Ca channel activity in a concentration-dependent manner within a physiological Ca 2+ range and a wide range of voltages, mainly by reducing mean closed time. The effect is essentially eliminated following chelation of Ca 2+ from the cytosolic face and pre-exposure to cholesterol-reducing agent methyl-β-cyclodextrin. O-1918 (3µM), a cannabidiol analog used as a selective antagonist of endothelial anandamide receptor, reduced BK Ca channel activity in inside-out patches. These results do not support the existence of endothelial cannabinoid receptor and indicate that anandamide acts as a direct BK Ca opener. The action does not require cell integrity or integrins and is caused by direct modification of BK Ca channel activity. Copyright © 2017 Elsevier B.V. All rights reserved.

Facilitated giga-seal formation with a just originated glass surface.

PubMed

Böhle, T; Benndorf, K

1994-07-01

A simple technique of tip preparation in patch pipettes is described, which facilitates giga-seal formation. The pipettes were fabricated from thick-walled borosilicate glass tubing (external diameter 2.0 mm, internal diameter 0.5 mm) and the tips could be repeatedly broken in the bath. The pipette resistance correspondingly fell in steps of 3-20 M omega from about 80 M omega to about 2 M omega (double concentrated Tyrode). Scanning electron microscopy showed that the tip obtained after breaking was fairly plain. These broken tips were especially appropriate for patch-clamping. In cardiac myocytes in 11 out of 26 patches with Na+ channel activity, giga-seals developed spontaneously, i.e. without suction. In these patches the amplitude of the mean current with depolarizing pulses to -40 mV was significantly higher in comparison with patches formed under negative pressure. It is concluded that spontaneously sealed patches are most likely of planar configuration and the Na+ channel activity exceeds that in suction-induced patches.

Computer-assisted liver graft steatosis assessment via learning-based texture analysis.

PubMed

Moccia, Sara; Mattos, Leonardo S; Patrini, Ilaria; Ruperti, Michela; Poté, Nicolas; Dondero, Federica; Cauchy, François; Sepulveda, Ailton; Soubrane, Olivier; De Momi, Elena; Diaspro, Alberto; Cesaretti, Manuela

2018-05-23

Fast and accurate graft hepatic steatosis (HS) assessment is of primary importance for lowering liver dysfunction risks after transplantation. Histopathological analysis of biopsied liver is the gold standard for assessing HS, despite being invasive and time consuming. Due to the short time availability between liver procurement and transplantation, surgeons perform HS assessment through clinical evaluation (medical history, blood tests) and liver texture visual analysis. Despite visual analysis being recognized as challenging in the clinical literature, few efforts have been invested to develop computer-assisted solutions for HS assessment. The objective of this paper is to investigate the automatic analysis of liver texture with machine learning algorithms to automate the HS assessment process and offer support for the surgeon decision process. Forty RGB images of forty different donors were analyzed. The images were captured with an RGB smartphone camera in the operating room (OR). Twenty images refer to livers that were accepted and 20 to discarded livers. Fifteen randomly selected liver patches were extracted from each image. Patch size was [Formula: see text]. This way, a balanced dataset of 600 patches was obtained. Intensity-based features (INT), histogram of local binary pattern ([Formula: see text]), and gray-level co-occurrence matrix ([Formula: see text]) were investigated. Blood-sample features (Blo) were included in the analysis, too. Supervised and semisupervised learning approaches were investigated for feature classification. The leave-one-patient-out cross-validation was performed to estimate the classification performance. With the best-performing feature set ([Formula: see text]) and semisupervised learning, the achieved classification sensitivity, specificity, and accuracy were 95, 81, and 88%, respectively. This research represents the first attempt to use machine learning and automatic texture analysis of RGB images from ubiquitous smartphone cameras for the task of graft HS assessment. The results suggest that is a promising strategy to develop a fully automatic solution to assist surgeons in HS assessment inside the OR.

Open-access microfluidic patch-clamp array with raised lateral cell trapping sites.

PubMed

Lau, Adrian Y; Hung, Paul J; Wu, Angela R; Lee, Luke P

2006-12-01

A novel open-access microfluidic patch-clamp array chip with lateral cell trapping sites raised above the bottom plane of the chip was developed by combining both a microscale soft-lithography and a macroscale polymer fabrication method. This paper demonstrates the capability of using such an open-access fluidic system for patch-clamp measurements. The surface of the open-access patch-clamp sites prepared by the macroscale hole patterning method of soft-state elastic polydimethylsiloxane (PDMS) is examined; the seal resistances are characterized and correlated with the aperture dimensions. Whole cell patch-clamp measurements are carried out with CHO cells expressing Kv2.1 ion channels. Kv2.1 ion channel blocker (TEA) dosage response is characterized and the binding activity is examined. The results demonstrate that the system is capable of performing whole cell measurements and drug profiling in a more efficient manner than the traditional patch-clamp set-up.

DoD Application Store: Enabling C2 Agility?

DTIC Science & Technology

2014-06-01

Framework, will include automated delivery of software patches, web applications, widgets and mobile application packages. The envisioned DoD...Marketplace within the Ozone Widget Framework, will include automated delivery of software patches, web applications, widgets and mobile application...current needs. DoD has started to make inroads within this environment with several Programs of Record (PoR) embracing widgets and other mobile

Fine-scale multi-species aggregations of oceanic zooplankton

NASA Astrophysics Data System (ADS)

Haury, L. R.; Wiebe, P. H.

1982-07-01

Sixteen Longhurst-Hardy Plankton Recorder tows were taken at different depths in the northwest Atlantic for analysis of fine-scale horizontal patchiness. Abundant species were non-randomly distributed in patches with scales of tens to hundreds of meters. Positive correlations between species abundances dominated, indicating that the patches were multi-species associations. Most horizontal pattern appeared to be of biological origin.

Spatial distribution of Madeira Island Laurisilva endemic spiders (Arachnida: Araneae)

PubMed Central

2014-01-01

Abstract Madeira island presents a unique spider diversity with a high number of endemic species, many of which are still poorly known. A recent biodiversity survey on the terrestrial arthropods of the native forest, Laurisilva, provided a large set of standardized samples from various patches throughout the island. Out of the fifty two species recorded, approximately 33.3% are Madeiran endemics, many of which had not been collected since their original description. Two new species to science are reported – Ceratinopsis n. sp. and Theridion n. sp. – and the first records of Poeciloneta variegata (Blackwall, 1841) and Tetragnatha intermedia Kulczynski, 1891 are reported for the first time for Madeira island. Considerations on species richness and abundance from different Laurisilva locations are presented, together with distribution maps for endemic species. These results contribute to a better understanding of spider diversity patterns and endemic species distribution in the native forest of Madeira island. PMID:24855443

Closure technique after carotid endarterectomy influences local hemodynamics.

PubMed

Harrison, Gareth J; How, Thien V; Poole, Robert J; Brennan, John A; Naik, Jagjeeth B; Vallabhaneni, S Rao; Fisher, Robert K

2014-08-01

Meta-analysis supports patch angioplasty after carotid endarterectomy (CEA); however, studies indicate considerable variation in practice. The hemodynamic effect of a patch is unclear and this study attempted to elucidate this and guide patch width selection. Four groups were selected: healthy volunteers and patients undergoing CEA with primary closure, trimmed patch (5 mm), or 8-mm patch angioplasty. Computer-generated three-dimensional models of carotid bifurcations were produced from transverse ultrasound images recorded at 1-mm intervals. Rapid prototyping generated models for flow visualization studies. Computational fluid dynamic studies were performed for each model and validated by flow visualization. Mean wall shear stress (WSS) and oscillatory shear index (OSI) maps were created for each model using pulsatile inflow at 300 mL/min. WSS of <0.4 Pa and OSI >0.3 were considered pathological, predisposing to accretion of intimal hyperplasia. The resultant WSS and OSI maps were compared. The four groups comprised 8 normal carotid arteries, 6 primary closures, 6 trimmed patches, and seven 8-mm patches. Flow visualization identified flow separation and recirculation at the bifurcation increased with a patch and was related to the patch width. Computational fluid dynamic identified that primary closure had the fewest areas of low WSS or elevated OSI but did have mild common carotid artery stenoses at the proximal arteriotomy that caused turbulence. Trimmed patches had more regions of abnormal WSS and OSI at the bifurcation, but 8-mm patches had the largest areas of deleteriously low WSS and high OSI. Qualitative comparison among the four groups confirmed that incorporation of a patch increased areas of low WSS and high OSI at the bifurcation and that this was related to patch width. Closure technique after CEA influences the hemodynamic profile. Patching does not appear to generate favorable flow dynamics. However, a trimmed 5-mm patch may offer hemodynamic benefits over an 8-mm patch and may be the preferred option. Copyright © 2014 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

A compact microwave patch applicator for hyperthermia treatment of cancer.

PubMed

Chakaravarthi, Geetha; Arunachalam, Kavitha

2014-01-01

Design and development of a compact microstrip C-type patch applicator for hyperthermia treatment of cancer is presented. The patch antenna is optimized for resonance at 434 MHz, return loss (S11) better than -15dB and co-polarized electric field in tissue. Effect of water bolus thickness on power delivery is studied for improved power coupling. Numerical simulations for antenna design optimization carried out using EM simulation software, Ansys HFSS(®), USA were experimentally verified. The effective field coverage for the optimized patch antenna and experimental results indicate that the compact antenna resonates at ISM frequency 434 MHz with better than -15 dB power coupling.

An experimental approach to free vibration analysis of smart composite beam

NASA Astrophysics Data System (ADS)

Yashavantha Kumar, G. A.; Sathish Kumar, K. M.

2018-02-01

Experimental vibration analysis is a main concern of this study. In designing any structural component the important parameter that has to be considered is vibration. The present work involves the experimental investigation of free vibration analysis of a smart beam. Smart beam consists of glass/epoxy composite as a main substrate and two PZT patches. The PZT patches are glued above and below the main beam. By experimentation the natural frequencies and mode shapes are obtained for both with and without PZT patches of a beam. Finally through experimentation the response of the smart beam is recorded.

Computer generated holographic microtags

DOEpatents

Sweatt, William C.

1998-01-01

A microlithographic tag comprising an array of individual computer generated holographic patches having feature sizes between 250 and 75 nanometers. The tag is a composite hologram made up of the individual holographic patches and contains identifying information when read out with a laser of the proper wavelength and at the proper angles of probing and reading. The patches are fabricated in a steep angle Littrow readout geometry to maximize returns in the -1 diffracted order. The tags are useful as anti-counterfeiting markers because of the extreme difficulty in reproducing them.

IET. Coupling station (TAN620) and service room section and details. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

IET. Coupling station (TAN-620) and service room section and details. Interior electrical features inside coupling station. Cable terminal assembly for patch panel for plug. Ralph M. Parsons 902-4-ANP-620-E 401. Date: February 1954. Approved by INEEL Classification Office for public release. INEEL index code no. 035-0620-10-693-106958 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

Integration of autopatching with automated pipette and cell detection in vitro

PubMed Central

Wu (吴秋雨), Qiuyu; Kolb, Ilya; Callahan, Brendan M.; Su, Zhaolun; Stoy, William; Kodandaramaiah, Suhasa B.; Neve, Rachael; Zeng, Hongkui; Boyden, Edward S.; Forest, Craig R.

2016-01-01

Patch clamp is the main technique for measuring electrical properties of individual cells. Since its discovery in 1976 by Neher and Sakmann, patch clamp has been instrumental in broadening our understanding of the fundamental properties of ion channels and synapses in neurons. The conventional patch-clamp method requires manual, precise positioning of a glass micropipette against the cell membrane of a visually identified target neuron. Subsequently, a tight “gigaseal” connection between the pipette and the cell membrane is established, and suction is applied to establish the whole cell patch configuration to perform electrophysiological recordings. This procedure is repeated manually for each individual cell, making it labor intensive and time consuming. In this article we describe the development of a new automatic patch-clamp system for brain slices, which integrates all steps of the patch-clamp process: image acquisition through a microscope, computer vision-based identification of a patch pipette and fluorescently labeled neurons, micromanipulator control, and automated patching. We validated our system in brain slices from wild-type and transgenic mice expressing channelrhodopsin 2 under the Thy1 promoter (line 18) or injected with a herpes simplex virus-expressing archaerhodopsin, ArchT. Our computer vision-based algorithm makes the fluorescent cell detection and targeting user independent. Compared with manual patching, our system is superior in both success rate and average trial duration. It provides more reliable trial-to-trial control of the patching process and improves reproducibility of experiments. PMID:27385800

Fast detection of extrasynaptic GABA with a whole-cell sniffer.

PubMed

Christensen, Rasmus K; Petersen, Anders V; Schmitt, Nicole; Perrier, Jean-François

2014-01-01

Gamma-amino-butyric acid (GABA) is the main inhibitory transmitter of the brain. It operates by binding to specific receptors located both inside and outside synapses. The extrasynaptic receptors are activated by spillover from GABAergic synapses and by ambient GABA in the extracellular space. Ambient GABA is essential for adjusting the excitability of neurons. However, due to the lack of suitable methods, little is known about its dynamics. Here we describe a new technique that allows detection of GABA transients and measurement of the steady state GABA concentration with high spatial and temporal resolution. We used a human embryonic kidney (HEK) cell line that stably expresses GABAA receptors composed of α1, β2, and γ2 subunits. We recorded from such a HEK cell with the whole-cell patch-clamp technique. The presence of GABA near the HEK cell generated a measurable electric current whose magnitude increased with concentration. A fraction of the current did not inactivate during prolonged exposition to GABA. This technique, which we refer to as a "sniffer" allows the measurement of ambient GABA concentration inside nervous tissue with a resolution of few tens of nanomolars. In addition, the sniffer detects variations in the extrasynaptic GABA concentration with millisecond time resolution. Pilot experiments demonstrate that the sniffer is able to report spillover of GABA induced by synaptic activation in real time. This is the first report on a GABA sensor that combines the ability to detect fast transients and to measure steady concentrations.

Fast detection of extrasynaptic GABA with a whole-cell sniffer

PubMed Central

Christensen, Rasmus K.; Petersen, Anders V.; Schmitt, Nicole; Perrier, Jean-François

2014-01-01

Gamma-amino-butyric acid (GABA) is the main inhibitory transmitter of the brain. It operates by binding to specific receptors located both inside and outside synapses. The extrasynaptic receptors are activated by spillover from GABAergic synapses and by ambient GABA in the extracellular space. Ambient GABA is essential for adjusting the excitability of neurons. However, due to the lack of suitable methods, little is known about its dynamics. Here we describe a new technique that allows detection of GABA transients and measurement of the steady state GABA concentration with high spatial and temporal resolution. We used a human embryonic kidney (HEK) cell line that stably expresses GABAA receptors composed of α1, β2, and γ2 subunits. We recorded from such a HEK cell with the whole-cell patch-clamp technique. The presence of GABA near the HEK cell generated a measurable electric current whose magnitude increased with concentration. A fraction of the current did not inactivate during prolonged exposition to GABA. This technique, which we refer to as a “sniffer” allows the measurement of ambient GABA concentration inside nervous tissue with a resolution of few tens of nanomolars. In addition, the sniffer detects variations in the extrasynaptic GABA concentration with millisecond time resolution. Pilot experiments demonstrate that the sniffer is able to report spillover of GABA induced by synaptic activation in real time. This is the first report on a GABA sensor that combines the ability to detect fast transients and to measure steady concentrations. PMID:24860433

Planar patch clamp for neuronal networks--considerations and future perspectives.

PubMed

Bosca, Alessandro; Martina, Marzia; Py, Christophe

2014-01-01

The patch-clamp technique is generally accepted as the gold standard for studying ion channel activity allowing investigators to either "clamp" membrane voltage and directly measure transmembrane currents through ion channels, or to passively monitor spontaneously occurring intracellular voltage oscillations. However, this resulting high information content comes at a price. The technique is labor-intensive and requires highly trained personnel and expensive equipment. This seriously limits its application as an interrogation tool for drug development. Patch-clamp chips have been developed in the last decade to overcome the tedious manipulations associated with the use of glass pipettes in conventional patch-clamp experiments. In this chapter, we describe some of the main materials and fabrication protocols that have been developed to date for the production of patch-clamp chips. We also present the concept of a patch-clamp chip array providing high resolution patch-clamp recordings from individual cells at multiple sites in a network of communicating neurons. On this chip, the neurons are aligned with the aperture-probes using chemical patterning. In the discussion we review the potential use of this technology for pharmaceutical assays, neuronal physiology and synaptic plasticity studies.

Functional role of hCngb3 in regulation of human cone cng channel: effect of rod monochromacy-associated mutations in hCNGB3 on channel function.

PubMed

Okada, Akira; Ueyama, Hisao; Toyoda, Futoshi; Oda, Sanae; Ding, Wei-Guang; Tanabe, Shoko; Yamade, Shinichi; Matsuura, Hiroshi; Ohkubo, Iwao; Kani, Kazutaka

2004-07-01

The human cone photoreceptor cyclic nucleotide-gated (CNG) channel comprises alpha- and beta-subunits, which are respectively encoded by hCNGA3 and hCNGB3. The purpose was to examine the functional role of hCNGB3 in modulation of human cone CNG channels and to characterize functional consequences of rod monochromacy-associated mutations in hCNGB3 (S435F and D633G). Macroscopic patch currents were recorded from human embryonic kidney (HEK) 293 cells expressing homomeric (hCNGA3 and hCNGB3) and heteromeric (hCNGA3/hCNGB3, hCNGA3/hCNGB3-S435F, and hCNGA3/hCNGB3-D633G) channels using inside-out patch-clamp technique. Both hCNGA3 homomeric and hCNGA3/hCNGB3 heteromeric channels were activated by cGMP, with half-maximally activating concentration (K(1/2)) of 11.1 +/- 1.0 and 26.2 +/- 1.9 micro M, respectively. The hCNGA3 channels appeared to be more sensitive to inhibition by extracellular Ca(2+) compared with hCNGA3/hCNGB3 channels, when assessed by the degree of outward rectification. Coexpression of either of rod monochromacy-associated mutants of hCNGB3 with hCNGA3 significantly reduced K(1/2) value for cGMP but little affected the sensitivity to extracellular Ca(2+), compared with wild-type heteromeric channels. The selectivity of hCNGA3, hCNGA3/hCNGB3, hCNGA3/hCNGB3-S435F, and hCNGA3/hCNGB3-D633G channels for monovalent cations were largely similar. Immunoprecipitation experiments showed association of hCNGA3 subunit with both of wild-type and mutant hCNGB3 subunits. The hCNGB3 plays an important modulatory role in the function of human cone CNG channels with respect to cGMP and extracellular Ca(2+) sensitivities. The rod monochromacy-associated S435F and D633G mutations in hCNGB3 evokes a significant increase in the apparent affinity for cGMP, which should alter cone function and thereby contribute at least partly to pathogenesis of the disease.

Distribution and function of HCN channels in the apical dendritic tuft of neocortical pyramidal neurons.

PubMed

Harnett, Mark T; Magee, Jeffrey C; Williams, Stephen R

2015-01-21

The apical tuft is the most remote area of the dendritic tree of neocortical pyramidal neurons. Despite its distal location, the apical dendritic tuft of layer 5 pyramidal neurons receives substantial excitatory synaptic drive and actively processes corticocortical input during behavior. The properties of the voltage-activated ion channels that regulate synaptic integration in tuft dendrites have, however, not been thoroughly investigated. Here, we use electrophysiological and optical approaches to examine the subcellular distribution and function of hyperpolarization-activated cyclic nucleotide-gated nonselective cation (HCN) channels in rat layer 5B pyramidal neurons. Outside-out patch recordings demonstrated that the amplitude and properties of ensemble HCN channel activity were uniform in patches excised from distal apical dendritic trunk and tuft sites. Simultaneous apical dendritic tuft and trunk whole-cell current-clamp recordings revealed that the pharmacological blockade of HCN channels decreased voltage compartmentalization and enhanced the generation and spread of apical dendritic tuft and trunk regenerative activity. Furthermore, multisite two-photon glutamate uncaging demonstrated that HCN channels control the amplitude and duration of synaptically evoked regenerative activity in the distal apical dendritic tuft. In contrast, at proximal apical dendritic trunk and somatic recording sites, the blockade of HCN channels decreased excitability. Dynamic-clamp experiments revealed that these compartment-specific actions of HCN channels were heavily influenced by the local and distributed impact of the high density of HCN channels in the distal apical dendritic arbor. The properties and subcellular distribution pattern of HCN channels are therefore tuned to regulate the interaction between integration compartments in layer 5B pyramidal neurons. Copyright © 2015 the authors 0270-6474/15/351024-14$15.00/0.

Glycogen synthase kinase 3 beta alters anxiety-, depression-, and addiction-related behaviors and neuronal activity in the nucleus accumbens shell

PubMed Central

Crofton, Elizabeth J.; Nenov, Miroslav N.; Zhang, Yafang; Scala, Federico; Page, Sean A.; McCue, David L.; Li, Dingge; Hommel, Jonathan D.; Laezza, Fernanda; Green, Thomas A.

2017-01-01

Psychiatric disorders such as anxiety, depression and addiction are often comorbid brain pathologies thought to share common mechanistic biology. As part of the cortico-limbic circuit, the nucleus accumbens shell (NAcSh) plays a fundamental role in integrating information in the circuit, such that modulation of NAcSh circuitry alters anxiety, depression, and addiction-related behaviors. Intracellular kinase cascades in the NAcSh have proven important mediators of behavior. To investigate glycogen-synthase kinase 3 (GSK3) beta signaling in the NAcSh in vivo we knocked down GSK3beta expression with a novel adeno-associated viral vector (AAV2) and assessed changes in anxiety- and depression-like behavior and cocaine self-administration in GSK3beta knockdown rats. GSK3beta knockdown reduced anxiety-like behavior while increasing depression-like behavior and cocaine self-administration. Correlative electrophysiological recordings in acute brain slices were used to assess the effect of AAV-shGSK3beta on spontaneous firing and intrinsic excitability of tonically active interneurons (TANs), cells required for input and output signal integration in the NAcSh and for processing reward-related behaviors. Loose-patch recordings showed that TANs transduced by AAV-shGSK3beta exhibited reduction in tonic firing and increased spike half width. When assessed by whole-cell patch clamp recordings these changes were mirrored by reduction in action potential firing and accompanied by decreased hyperpolarization-induced depolarizing sag potentials, increased action potential current threshold, and decreased maximum rise time. These results suggest that silencing of GSK3beta in the NAcSh increases depression- and addiction-related behavior, possibly by decreasing intrinsic excitability of TANs. However, this study does not rule out contributions from other neuronal sub-types. PMID:28126496

Simultaneous recording of fluorescence and electrical signals by photometric patch electrode in deep brain regions in vivo

PubMed Central

Hirai, Yasuharu; Nishino, Eri

2015-01-01

Despite its widespread use, high-resolution imaging with multiphoton microscopy to record neuronal signals in vivo is limited to the surface of brain tissue because of limited light penetration. Moreover, most imaging studies do not simultaneously record electrical neural activity, which is, however, crucial to understanding brain function. Accordingly, we developed a photometric patch electrode (PME) to overcome the depth limitation of optical measurements and also enable the simultaneous recording of neural electrical responses in deep brain regions. The PME recoding system uses a patch electrode to excite a fluorescent dye and to measure the fluorescence signal as a light guide, to record electrical signal, and to apply chemicals to the recorded cells locally. The optical signal was analyzed by either a spectrometer of high light sensitivity or a photomultiplier tube depending on the kinetics of the responses. We used the PME in Oregon Green BAPTA-1 AM-loaded avian auditory nuclei in vivo to monitor calcium signals and electrical responses. We demonstrated distinct response patterns in three different nuclei of the ascending auditory pathway. On acoustic stimulation, a robust calcium fluorescence response occurred in auditory cortex (field L) neurons that outlasted the electrical response. In the auditory midbrain (inferior colliculus), both responses were transient. In the brain-stem cochlear nucleus magnocellularis, calcium response seemed to be effectively suppressed by the activity of metabotropic glutamate receptors. In conclusion, the PME provides a powerful tool to study brain function in vivo at a tissue depth inaccessible to conventional imaging devices. PMID:25761950

Simultaneous recording of fluorescence and electrical signals by photometric patch electrode in deep brain regions in vivo.

PubMed

Hirai, Yasuharu; Nishino, Eri; Ohmori, Harunori

2015-06-01

Despite its widespread use, high-resolution imaging with multiphoton microscopy to record neuronal signals in vivo is limited to the surface of brain tissue because of limited light penetration. Moreover, most imaging studies do not simultaneously record electrical neural activity, which is, however, crucial to understanding brain function. Accordingly, we developed a photometric patch electrode (PME) to overcome the depth limitation of optical measurements and also enable the simultaneous recording of neural electrical responses in deep brain regions. The PME recoding system uses a patch electrode to excite a fluorescent dye and to measure the fluorescence signal as a light guide, to record electrical signal, and to apply chemicals to the recorded cells locally. The optical signal was analyzed by either a spectrometer of high light sensitivity or a photomultiplier tube depending on the kinetics of the responses. We used the PME in Oregon Green BAPTA-1 AM-loaded avian auditory nuclei in vivo to monitor calcium signals and electrical responses. We demonstrated distinct response patterns in three different nuclei of the ascending auditory pathway. On acoustic stimulation, a robust calcium fluorescence response occurred in auditory cortex (field L) neurons that outlasted the electrical response. In the auditory midbrain (inferior colliculus), both responses were transient. In the brain-stem cochlear nucleus magnocellularis, calcium response seemed to be effectively suppressed by the activity of metabotropic glutamate receptors. In conclusion, the PME provides a powerful tool to study brain function in vivo at a tissue depth inaccessible to conventional imaging devices. Copyright © 2015 the American Physiological Society.

The activation of calcium and calcium-activated potassium channels in mammalian colonic smooth muscle by substance P.

PubMed Central

Mayer, E A; Loo, D D; Snape, W J; Sachs, G

1990-01-01

1. The regulation of Ca2(+)-activated K+ channels by the agonist substance P in freshly dissociated smooth muscle cells from the rabbit longitudinal colonic muscle was characterized using the patch clamp technique. 2. In the cell-attached recording mode, when pipette and bath solutions contained equal [K+] (126 mM), the Ca2(+)-activated K+ channels showed a linear current-voltage relationship (between -50 mV and 50 mV) with a slope conductance of 210 +/- 35 pS (n = 12). Reversal potential measurements indicated that the channel was highly selective for K+ over Na+ (PK/PNa = 110). 3. Channels were activated by depolarizing membrane voltages and cytosolic Ca2+, and in inside-out patches channel activation depended sigmoidally on voltage and [Ca2+]. The potential for half-activation at a cytosolic [Ca2+] of 5 x 10(-6) M was 0 mV. A tenfold increase in cytosolic Ca2+ resulted in a 60 mV shift of the sigmoidal voltage activation curve to more negative potentials. 4. Threshold concentrations of substance P (10(-12) M), which did not result in cell contraction, caused a prolonged activation of K+ channels. The K+ channels were observed to open in clusters: simultaneous opening of multiple channels was interrupted by complete, prolonged channel closure. 5. Lowering bath [Ca2+] to submicromolar concentrations abolished the effect of substance P. The activation of K+ channels by substance P (10(-12) M) was also inhibited by the dihydropyridine nifedipine (10(-6) M), a blocker of L-type Ca2+ channels. 6. In the whole-cell recording mode, with the pipette solution containing 126 mM-KCl, 0.77 mM-EGTA and 1 mM-ATP, depolarization from a holding potential of -70 mV elicited outward currents which increased to steady-state values. These were K+ currents as they were blocked by TEA (tetraethylammonium, 30 mM) and Ba2+ (1 mM) and were abolished when pipette K+ was replaced by Cs+. 7. The depolarization-activated outward current was not affected by lowering extracellular [Ca2+] or by the Ca2+ channel antagonists Cd2+ (200 microM), nifedipine (10(-6)-10(-5) M) or verapamil (10(-6) M). The current was greatly reduced when the EGTA concentration in the pipette solution was increased from 0.77 to 10 mM. 8. When the pipette solution contained CsCl, membrane depolarization activated inward currents. The peak inward current was identified as current through L-type Ca2+ channels based on its voltage- and time-dependent kinetics, and its modulation by dihydropyridines.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1691293

Optimal Location of Piezoelectric Patch on Composite Structure using Viewing Method

NASA Astrophysics Data System (ADS)

Samyal, Rahul; Bagha, Ashok K.

2017-08-01

A useful material which is manufactured by mixing of two or three different materials in homogeneous level is termed as composite material. In now day’s composite materials are used in wide area such as aerospace, automobiles, satellite, bullet proof jackets, rotor blades etc. In this paper modal analysis of composite material, mixture of polyester as matrix and glass as fiber, is carried out by using ABAQUS software. The modal analysis of composite material for fiber orientation 450 is carried out. In this paper by viewing the different mode shapes of the composite material, the optimal location of piezoelectric patch is carried out.

De Sitter Space Without Dynamical Quantum Fluctuations

NASA Astrophysics Data System (ADS)

Boddy, Kimberly K.; Carroll, Sean M.; Pollack, Jason

2016-06-01

We argue that, under certain plausible assumptions, de Sitter space settles into a quiescent vacuum in which there are no dynamical quantum fluctuations. Such fluctuations require either an evolving microstate, or time-dependent histories of out-of-equilibrium recording devices, which we argue are absent in stationary states. For a massive scalar field in a fixed de Sitter background, the cosmic no-hair theorem implies that the state of the patch approaches the vacuum, where there are no fluctuations. We argue that an analogous conclusion holds whenever a patch of de Sitter is embedded in a larger theory with an infinite-dimensional Hilbert space, including semiclassical quantum gravity with false vacua or complementarity in theories with at least one Minkowski vacuum. This reasoning provides an escape from the Boltzmann brain problem in such theories. It also implies that vacuum states do not uptunnel to higher-energy vacua and that perturbations do not decohere while slow-roll inflation occurs, suggesting that eternal inflation is much less common than often supposed. On the other hand, if a de Sitter patch is a closed system with a finite-dimensional Hilbert space, there will be Poincaré recurrences and dynamical Boltzmann fluctuations into lower-entropy states. Our analysis does not alter the conventional understanding of the origin of density fluctuations from primordial inflation, since reheating naturally generates a high-entropy environment and leads to decoherence, nor does it affect the existence of non-dynamical vacuum fluctuations such as those that give rise to the Casimir effect.

Application of a buprenorphine transdermal patch for the perioperative analgesia in patients who underwent simple lumbar discectomy

PubMed Central

Tang, Jian; Fan, Jin; Yao, Yilun; Cai, Weihua; Yin, Guoyong; Zhou, Wei

2017-01-01

Abstract This study aimed to investigate the perioperative analgesic effect of a buprenorphine transdermal patch in patients who underwent simple lumbar discectomy. In total, 96 patients were randomly divided into parecoxib intravenous injection (Group A), oral celecoxib (Group B), and buprenorphine transdermal patch groups (Group C). The pain status, degree of satisfaction, adverse effects, and condition in which the patient received tramadol hydrochloride for uncontrolled pain were recorded on the night before surgery, postoperative day 1, postoperative day 3, and postoperative day 5. The degree of patient satisfaction in Group C was higher than that in Groups A and B, with minimal adverse effects. The buprenorphine transdermal patch had a better perioperative analgesic effect in patients who underwent simple lumbar discectomy. PMID:28514299

Effects of nanotechnologies-based devices on postural control in healthy subjects.

PubMed

Malchiodi Albedi, Giovanna; Corna, Stefano; Aspesi, Valentina; Clerici, Daniela; Parisio, Cinzia; Seitanidis, Jonathan; Cau, Nicola; Brugliera, Luigia; Capodaglio, Paolo

2017-09-05

The aim of the present preliminary randomized controlled study was to ascertain whether the use of newly developed nanotechnologies-based patches can influence posture control of healthy subjects. Thirty healthy female subjects (age 39.4 years, BMI 22.74 kg/m2) were randomly assigned to two groups: one with active patches and a control group with sham patches. Two patches were applied with a tape: one on the subject's sternum and the other on the C7 apophysis. Body sway during quiet upright stance was recorded with a dynamometric platform. Each subject was tested under two visual conditions, eyes open and closed. We used a blocked stratified randomization procedure conducted by a third party. Subjects wearing the sham patches showed a significant increase of the centre of pressure sway area after 4 hours when they performed the habitual moderate-intensity work activities. In the active patch group, a decrease of the sway path was evident, providing evidence of an enhanced balance control. Our preliminary findings on healthy subjects indicate that nanotechnological devices generating ultra-low electromagnetic fields can improve posture control.

Cosmonaut Krikalev with IMAX camera prior to hatch opening

NASA Image and Video Library

2001-02-11

STS98-E-5124 (11 February 2001) --- Cosmonaut Sergei K. Krikalev, Expedition One flight engineer representing the Russian Aviation and Space Agency, films activity in the Unity node, just outside the newly attached Destiny laboratory. The crews of Atlantis and the International Space Station on February 11 opened the Destiny laboratory and spent the first full day of what are planned to be years of work ahead inside the orbiting science and command center. Astronaut William M. (Bill) Shepherd (just out of frame here) opened the Destiny hatch, and he and Shuttle commander Kenneth D. Cockrell ventured inside at 8:38 a.m. (CST). Members of both crews went to work quickly inside the new module, activating air systems, fire extinguishers, alarm systems, computers and internal communications. The crew also continued equipment transfers from the shuttle to the station and filmed several scenes onboard the station using the IMAX camera. This scene was recorded with a digital still camera.

Primary alcohols activate human TRPA1 channel in a carbon chain length-dependent manner.

PubMed

Komatsu, Tomoko; Uchida, Kunitoshi; Fujita, Fumitaka; Zhou, Yiming; Tominaga, Makoto

2012-04-01

Transient receptor potential ankyrin 1 (TRPA1) is a calcium-permeable non-selective cation channel that is mainly expressed in primary nociceptive neurons. TRPA1 is activated by a variety of noxious stimuli, including cold temperatures, pungent compounds such as mustard oil and cinnamaldehyde, and intracellular alkalization. Here, we show that primary alcohols, which have been reported to cause skin, eye or nasal irritation, activate human TRPA1 (hTRPA1). We measured intracellular Ca(2+) changes in HEK293 cells expressing hTRPA1 induced by 1 mM primary alcohols. Higher alcohols (1-butanol to 1-octanol) showed Ca(2+) increases proportional to the carbon chain length. In whole-cell patch-clamp recordings, higher alcohols (1-hexanol to 1-octanol) activated hTRPA1 and the potency increased with the carbon chain length. Higher alcohols evoked single-channel opening of hTRPA1 in an inside-out configuration. In addition, cysteine at 665 in the N terminus and histidine at 983 in the C terminus were important for hTRPA1 activation by primary alcohols. Furthermore, straight-chain secondary alcohols increased intracellular Ca(2+) concentrations in HEK293 cells expressing hTRPA1, and both primary and secondary alcohols showed hTRPA1 activation activities that correlated highly with their octanol/water partition coefficients. On the other hand, mouse TRPA1 did not show a strong response to 1-hexanol or 1-octanol, nor did these alcohols evoke significant pain in mice. We conclude that primary and secondary alcohols activate hTRPA1 in a carbon chain length-dependent manner. TRPA1 could be a sensor of alcohols inducing skin, eye and nasal irritation in human.

Pre-Steady-State Kinetics of Ba-Ca Exchange Reveals a Second Electrogenic Step Involved in Ca2+ Translocation by the Na-Ca Exchanger

PubMed Central

Haase, Andreas; Hartung, Klaus

2009-01-01

Kinetic properties of the Na-Ca exchanger (guinea pig NCX1) expressed in Xenopus oocytes were investigated with excised membrane patches in the inside-out configuration and photolytic Ca2+ concentration jumps with either 5 mM extracellular Sr2+ or Ba2+. After a Ca2+ concentration jump on the cytoplasmic side, the exchanger performed Sr-Ca or Ba-Ca exchange. In the Sr-Ca mode, currents are transient and decay in a monoexponential manner similar to that of currents in the Ca-Ca exchange mode described before. Currents recorded in the Ba-Ca mode are also transient, but the decay is biphasic. In the Sr-Ca mode the amount of charge translocated increases at negative potentials in agreement with experiments performed in the Ca-Ca mode. In the Ba-Ca mode the total amount of charge translocated after a Ca2+ concentration jump is ∼4 to 5 times that in Ca-Ca or Sr-Ca mode. In the Ba-Ca mode the voltage dependence of charge translocation depends on the Ca2+ concentration on the cytosolic side before the Ca2+ concentration jump. At low initial Ca2+ levels (∼0.5 μM), charge translocation is voltage independent. At a higher initial concentration (1 μM Ca2+), the amount of charge translocated increases at positive potentials. Biphasic relaxation of the current was also observed in the Ca-Ca mode if the external Ca2+ concentration was reduced to ≤0.5 mM. The results reported here and in previous publications can be described by using a 6-state model with two voltage-dependent conformational transitions. PMID:19486679

Clinical Concentrations of Local Anesthetics Bupivacaine and Lidocaine Differentially Inhibit Human Kir2.x Inward Rectifier K+ Channels.

PubMed

Nakahira, Kei; Oshita, Kensuke; Itoh, Masayuki; Takano, Makoto; Sakaguchi, Yoshiro; Ishihara, Keiko

2016-04-01

Inward rectifier K channels of the Kir2.x subfamily are widely expressed in neuronal tissues, controlling neuronal excitability. Previous studies reported that local anesthetics (LAs) do not affect Kir2 channels. However, the effects have not been studied at large concentrations used in regional anesthesia. This study used the patch-clamp technique to examine the effects of bupivacaine and lidocaine on Kir2.1, Kir2.2, and Kir2.3 channels expressed in human embryonic kidney 293 cells. When applied extracellularly in whole-cell recordings, both LAs inhibited Kir2.x currents in a voltage-independent manner. Inhibition with bupivacaine was slow and irreversible, whereas that with lidocaine was fast and reversible. Kir2.3 displayed a greater sensitivity to bupivacaine than Kir2.1 and Kir2.2 (50% inhibitory concentrations at approximately 5 minutes, 0.6 vs 8-10 mM), whereas their sensitivities to lidocaine were similar (50% inhibitory concentrations, 1.5-2.7 mM). Increases in the charged/neutral ratio of the LAs at an acidic extracellular pH attenuated their inhibitory effects, and a permanently charged lidocaine derivative QX-314 exhibited no effects when applied extracellularly. Inside-out experiments demonstrated that inhibition of Kir2.1 with cytoplasmic lidocaine and QX-314 was rapid and reversible, whereas that induced by bupivacaine was slow and irreversible. Furthermore, dose-inhibition relations for the charged form of bupivacaine and lidocaine obtained at different cytoplasmic pHs could be approximated by a single relation for each LA. The results indicate that both LAs at clinical concentrations equilibrated rapidly with the intracellular milieu, differentially inhibiting Kir2.x channel function from the cytoplasmic side.

Phosphoinositides Regulate P2X4 ATP-Gated Channels through Direct Interactions

PubMed Central

Bernier, Louis-Philippe; Ase, Ariel R.; Chevallier, Stéphanie; Blais, Dominique; Zhao, Qi; Boué-Grabot, Éric; Logothetis, Diomedes; Séguéla, Philippe

2008-01-01

P2X receptors are ATP-gated nonselective cation channels highly permeable to calcium that contribute to nociception and inflammatory responses. The P2X4 subtype, upregulated in activated microglia, is thought to play a critical role in the development of tactile allodynia following peripheral nerve injury. Posttranslational regulation of P2X4 function is crucial to the cellular mechanisms of neuropathic pain, however it remains poorly understood. Here, we show that the phosphoinositides PI(4,5)P2 (PIP2) and PI(3,4,5)P3 (PIP3), products of phosphorylation by wortmannin-sensitive phosphatidylinositol 4-kinases and phosphatidylinositol 3-kinases, can modulate the function of native and recombinant P2X4 receptor channels. In BV-2 microglial cells, depleting the intracellular levels of PIP2 and PIP3 with wortmannin significantly decreased P2X4 current amplitude and P2X4-mediated calcium entry measured in patch clamp recordings and ratiometric ion imaging, respectively. Wortmannin-induced depletion of phosphoinositides in Xenopus oocytes decreased the current amplitude of P2X4 responses by converting ATP into a partial agonist. It also decreased their recovery from desensitization and affected their kinetics. Injection of phosphoinositides in wortmannin-treated oocytes reversed these effects and application of PIP2 on excised inside-out macropatches rescued P2X4 currents from rundown. Moreover, we report the direct interaction of phospholipids with the proximal C-terminal domain of P2X4 subunit (Cys360-Val375) using an in vitro binding assay. These results demonstrate novel regulatory roles of the major signaling phosphoinositides PIP2 and PIP3 on P2X4 function through direct channel-lipid interactions. PMID:19036987

Background and tandem-pore potassium channels in magnocellular neurosecretory cells of the rat supraoptic nucleus

PubMed Central

Han, Jaehee; Gnatenco, Carmen; Sladek, Celia D; Kim, Donghee

2003-01-01

Magnocellular neurosecretory cells (MNCs) were isolated from the supraoptic nucleus of rat hypothalamus, and properties of K+ channels that may regulate the resting membrane potential and the excitability of MNCs were studied. MNCs showed large transient outward currents, typical of vasopressin- and oxytocin-releasing neurons. K+ channels in MNCs were identified by recording K+ channels that were open at rest in cell-attached and inside-out patches in symmetrical 150 mm KCl. Eight different K+ channels were identified and could be distinguished unambiguously by their single-channel kinetics and voltage-dependent rectification. Two K+ channels could be considered functional correlates of TASK-1 and TASK-3, as judged by their single-channel kinetics and high sensitivity to pHo. Three K+ channels showed properties similar to TREK-type tandem-pore K+ channels (TREK-1, TREK-2 and a novel TREK), as judged by their activation by membrane stretch, intracellular acidosis and arachidonic acid. One K+ channel was activated by application of pressure, arachidonic acid and alkaline pHi, and showed single-channel kinetics indistinguishable from those of TRAAK. One K+ channel showed strong inward rectification and single-channel conductance similar to those of a classical inward rectifier, IRK3. Finally, a K+ channel whose cloned counterpart has not yet been identified was highly sensitive to extracellular pH near the physiological range similar to those of TASK channels, and was the most active among all K+ channels. Our results show that in MNCs at rest, eight different types of K+ channels can be found and six of them belong to the tandem-pore K+ channel family. Various physiological and pathophysiological conditions may modulate these K+ channels and regulate the excitability of MNCs. PMID:12562991

Riluzole activates TRPC5 channels independently of PLC activity

PubMed Central

Richter, Julia M; Schaefer, Michael; Hill, Kerstin

2014-01-01

BACKGROUND AND PURPOSE The transient receptor potential channel C5 (TRPC5) is a Ca2+-permeable cation channel, which is predominantly expressed in the brain. TRPC5 is activated in a PLC-dependent manner by, as yet, unidentified endogenous messengers. Recently, modulators of TRPC5, like Ca2+, pH and phospholipids, have been identified. However, the role of TRPC5 in vivo is only poorly understood. Novel specific modulators of TRPC5 might help to elucidate its function. EXPERIMENTAL APPROACH Novel modulators of TRPC5 were identified in a compound screening of approved drugs and natural compounds. The potency and selectivity of TRPC5-activating compounds were determined by fluorometric calcium imaging. The biophysical properties of channel activation by these compounds were analysed using electrophysiological measurements. KEY RESULTS Riluzole was identified as a novel activator of TRPC5 (EC50 9.2 ± 0.5 μM) and its mechanism of action was shown to be independent of G protein signalling and PLC activity. Riluzole-induced TRPC5 currents were potentiated by La3+ and, utilizing TRPC5 mutants that lack La3+ binding sites, it was confirmed that riluzole and La3+ activate TRPC5 by different mechanisms. Recordings of excised inside-out patches revealed a relatively direct effect of riluzole on TRPC5. CONCLUSIONS AND IMPLICATIONS Riluzole can activate TRPC5 heterologously expressed in HEK293 cells as well as those endogenously expressed in the U-87 glioblastoma cell line. Riluzole does not activate any other member of the TRPC family and could, therefore, despite its action on other ion channels, be a useful pharmacological tool for identifying TRPC5-specific currents in immortalized cell lines or in acutely isolated primary cells. PMID:24117252

Development of a self-stressing NiTiNb shape memory alloy (SMA)/fiber reinforced polymer (FRP) patch

NASA Astrophysics Data System (ADS)

El-Tahan, M.; Dawood, M.; Song, G.

2015-06-01

The objective of this research is to develop a self-stressing patch using a combination of shape memory alloys (SMAs) and fiber reinforced polymer (FRP) composites. Prestressed carbon FRP patches are emerging as a promising alternative to traditional methods to repair cracked steel structures and civil infrastructure. However, prestressing these patches typically requires heavy and complex fixtures, which is impractical in many applications. This paper presents a new approach in which the prestressing force is applied by restraining the shape memory effect of NiTiNb SMA wires. The wires are subsequently embedded in an FRP overlay patch. This method overcomes the practical challenges associated with conventional prestressing. This paper presents the conceptual development of the self-stressing patch with the support of experimental observations. The bond between the SMA wires and the FRP is evaluated using pull-out tests. The paper concludes with an experimental study that evaluates the patch response during activation subsequent monotonic tensile loading. The results demonstrate that the self-stressing patch with NiTiNb SMA is capable of generating a significant prestressing force with minimal tool and labor requirements.

A fast solution switching system with temperature control for single cell measurements

PubMed Central

Koh, Duk-Su; Chen, Liangyi; Ufret-Vincenty, Carmen A.; Jung, Seung-Ryoung

2011-01-01

This article describes a perfusion system for biophysical single cell experiments at the physiological temperature. Our system regulates temperature of test solutions using a small heat exchanger that includes several capillaries. Water circulating inside the heat exchanger warms or cools test solutions flowing inside the capillaries. Temperature-controlled solutions are delivered directly to a single cell(s) through a multibarreled manifold that switches solutions bathing a cell in less than 1 s. This solution exchange is optimal for patch clamp, single-cell microamperometry, and microfluorometry experiments. Using this system, we demonstrate that exocytosis from pancreatic β cells and activation of TRPV1 channels are temperature sensitive. We also discuss how to measure local temperature near a single cell under investigation. PMID:21536068

Assessment of optimal strategies in a two-patch dengue transmission model with seasonality.

PubMed

Kim, Jung Eun; Lee, Hyojung; Lee, Chang Hyeong; Lee, Sunmi

2017-01-01

Emerging and re-emerging dengue fever has posed serious problems to public health officials in many tropical and subtropical countries. Continuous traveling in seasonally varying areas makes it more difficult to control the spread of dengue fever. In this work, we consider a two-patch dengue model that can capture the movement of host individuals between and within patches using a residence-time matrix. A previous two-patch dengue model without seasonality is extended by adding host demographics and seasonal forcing in the transmission rates. We investigate the effects of human movement and seasonality on the two-patch dengue transmission dynamics. Motivated by the recent Peruvian dengue data in jungle/rural areas and coast/urban areas, our model mimics the seasonal patterns of dengue outbreaks in two patches. The roles of seasonality and residence-time configurations are highlighted in terms of the seasonal reproduction number and cumulative incidence. Moreover, optimal control theory is employed to identify and evaluate patch-specific control measures aimed at reducing dengue prevalence in the presence of seasonality. Our findings demonstrate that optimal patch-specific control strategies are sensitive to seasonality and residence-time scenarios. Targeting only the jungle (or endemic) is as effective as controlling both patches under weak coupling or symmetric mobility. However, focusing on intervention for the city (or high density areas) turns out to be optimal when two patches are strongly coupled with asymmetric mobility.

A Contact Pressure Analysis Comparing an All-Inside and Inside-Out Surgical Repair Technique for Bucket-Handle Medial Meniscus Tears.

PubMed

Marchetti, Daniel Cole; Phelps, Brian M; Dahl, Kimi D; Slette, Erik L; Mikula, Jacob D; Dornan, Grant J; Bucci, Gabriella; Turnbull, Travis Lee; Singleton, Steven B

2017-10-01

To directly compare effectiveness of the inside-out and all-inside medial meniscal repair techniques in restoring native contact area and contact pressure across the medial tibial plateau at multiple knee flexion angles. Twelve male, nonpaired (n = 12), fresh-frozen human cadaveric knees underwent a series of 5 consecutive states: (1) intact medial meniscus, (2) MCL tear and repair, (3) simulated bucket-handle longitudinal tear of the medial meniscus, (4) inside-out meniscal repair, and (5) all-inside meniscal repair. Knees were loaded with a 1,000-N axial compressive force at 5 knee flexion angles (0°, 30°, 45°, 60°, 90°), and contact area, mean contact pressure, and peak contact pressure were calculated using thin film pressure sensors. No significant differences were observed between the inside-out and all-inside repair techniques at any flexion angle for contact area, mean contact pressure, and peak contact pressure (all P > .791). Compared with the torn meniscus state, inside-out and all-inside repair techniques resulted in increased contact area at all flexion angles (all P < .005 and all P < .037, respectively), decreased mean contact pressure at all flexion angles (all P < .007 and all P < .001, respectively) except for 0° (P = .097 and P = .39, respectively), and decreased peak contact pressure at all flexion angles (all P < .001, all P < .001, respectively) except for 0° (P = .080 and P = .544, respectively). However, there were significant differences in contact area and peak contact pressure between the intact state and inside-out technique at angles ≥45° (all P < .014 and all P < .032, respectively). Additionally, there were significant differences between the intact state and all-inside technique in contact area at 60° and 90° and peak contact pressure at 90° (both P < .005 and P = .004, respectively). Median values of intact contact area, mean contact pressure, and peak contact pressure over the tested flexion angles ranged from 498 to 561 mm 2 , 786 to 997 N/mm 2 , and 1,990 to 2,215 N/mm 2 , respectively. Contact area, mean contact pressure, and peak contact pressure were not significantly different between the all-inside and inside-out repair techniques at any tested flexion angle. Both techniques adequately restored native meniscus biomechanics near an intact level. An all-inside repair technique provided similar, native-state-restoring contact mechanics compared with an inside-out repair technique for the treatment of displaced bucket-handle tears of the medial meniscus. Thus, both techniques may adequately decrease the likelihood of cartilage degeneration. Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Human motion energy harvesting using a piezoelectric MFC patch.

PubMed

Bassani, Giulia; Filippeschi, Alessandro; Ruffaldi, Emanuele

2015-01-01

The improvements in efficiency of electronic components and miniaturization is quickly pushing wearable devices. Kinetic human energy harvesting is a way to power these components reducing the need of batteries replacement since walking or running is how humans already expend much of their daily energy. This work explores the case of kinetic energy from bending of a piezoelectric patch. For assessing the quality of the system, a testing setup has been designed and controlled by means of knee joint recordings obtained from a large motion dataset. The promising result of the chosen patch is an output power of 2.6μW associated to a run activity.

Patch Testing in Patients with Suspected Footwear Dermatitis: A Retrospective Study.

PubMed

Garg, Taru; Agarwal, Soumya; Rana, Shiwangi; Chander, Ram

2017-01-01

Footwear dermatitis represents a common but often undiagnosed or misdiagnosed condition. Patch testing aids in its confirmation and identification of the offending allergen. This study aimed to find the frequency of positive patch test reactions in cases with suspected allergic contact dermatitis (ACD) to footwear, as well as the common responsible allergens. This is a retrospective record based study of 37 patients, with suspected ACD to footwear, who underwent patch testing with Indian standard series and Indian footwear series from July 2012 to July 2015. The majority of patients (45.94%) belonged to the age group of 20-40 years. Dorsal aspects of feet (81.08%) and soles (18.92%) were the common sites involved. Patch test was positive in 18.92% patients. The most common causative allergens were hydroquinone monobenzylether (8.11%) and 4-aminoazobenzene (5.41%). Common chemicals implicated in ACD were rubber, rubber additives, and dyes. The principal culprit allergens were hydroquinone monobenzylether and 4-aminoazobenzene.

Operationalizing Cyberspace for Today’s Combat Air Force

DTIC Science & Technology

2010-04-01

rootkit techniques to run inside common Windows services (sometimes bundled with fake antivirus software ) or in Windows safe mode, and it can hide...has shifted to downloading other malware, with its main focus on fake alerts and rogue antivirus software . 5. TR/Dldr.Agent.JKH - Compromised U.S...patch, software update, or security breech away from failure. In short, what works AU/ACSC/SIMMONS/AY10 5 today, may not work tomorrow; this fact

Robust Airborne Networking Extensions (RANGE)

DTIC Science & Technology

2008-02-01

IMUNES [13] project, which provides an entire network stack virtualization and topology control inside a single FreeBSD machine . The emulated topology...Multicast versus broadcast in a manet.” in ADHOC-NOW, 2004, pp. 14–27. [9] J. Mukherjee, R. Atwood , “ Rendezvous point relocation in protocol independent...computer with an Ethernet connection, or a Linux virtual machine on some other (e.g., Windows) operating system, should work. 2.1 Patching the source code

A Comparison of the Performance and Application Differences Between Manual and Automated Patch-Clamp Techniques

PubMed Central

Yajuan, Xiao; Xin, Liang; Zhiyuan, Li

2012-01-01

The patch clamp technique is commonly used in electrophysiological experiments and offers direct insight into ion channel properties through the characterization of ion channel activity. This technique can be used to elucidate the interaction between a drug and a specific ion channel at different conformational states to understand the ion channel modulators’ mechanisms. The patch clamp technique is regarded as a gold standard for ion channel research; however, it suffers from low throughput and high personnel costs. In the last decade, the development of several automated electrophysiology platforms has greatly increased the screen throughput of whole cell electrophysiological recordings. New advancements in the automated patch clamp systems have aimed to provide high data quality, high content, and high throughput. However, due to the limitations noted above, automated patch clamp systems are not capable of replacing manual patch clamp systems in ion channel research. While automated patch clamp systems are useful for screening large amounts of compounds in cell lines that stably express high levels of ion channels, the manual patch clamp technique is still necessary for studying ion channel properties in some research areas and for specific cell types, including primary cells that have mixed cell types and differentiated cells that derive from induced pluripotent stem cells (iPSCs) or embryonic stem cells (ESCs). Therefore, further improvements in flexibility with regard to cell types and data quality will broaden the applications of the automated patch clamp systems in both academia and industry. PMID:23346269

Is in-stream macrophyte growth predictable and what are its impacts on channel-averaged flow characteristics?

NASA Astrophysics Data System (ADS)

Jordan, David N.; Thomas, Robert E.; Keevil, Gareth M.; Parsons, Daniel R.; Hardy, Richard J.

2016-04-01

Understanding how the growth of aquatic vegetation impacts stage-discharge coupling is vital for river management planning. This study presents an annual record of monthly spatial distribution surveys of the in-stream macrophyte Ranunculus penicillatus coupled with channel form and flow velocity measurements, within a 50 m-long reach of a gravel-bed river. Whereas stage has varied by up to 0.4 m, there has been little change in channel form over the monitoring period (ongoing since 23/07/2014). Macrophyte growth continued from the start of the monitoring period until October 2014 when mean patch area was 6.74 m2, and then decreased throughout a decay phase until January 2015 when mean patch area was 1.12 m2. There was a 75.2% loss of macrophyte surface area between October 2014 and January 2015. The largest patches that remained in January 2015 continued to decay until February. Conversely, new macrophyte patches also began to recolonize the channel during this time. To our knowledge, this is the first evidence of a transition period during which aquatic vegetation is in both decay and recolonization phases simultaneously. In total 69% of patches present in January exhibited regrowth without further decay to form a base for recolonization. Therefore, the spatial distribution of macrophyte patches could be determined to be somewhat persistent. Despite this, due to several different growth factors, there are recognisable differences in both macrophyte patch shape and distribution when comparing data from July 2014 and July 2015, emphasising the unpredictability of macrophyte growth. The decay period of the Ranunculus p. coincided with seasonal high discharges in this catchment. Discharge remained high from January until March 2015, but then began to decrease, reflecting annual peaks in historical records for the study area. Large discharge variations were not matched by a large stage range. Displacement of water by vegetation growth maintained the stage height when discharge rates fell. Greater understanding of the relationship between discharge and growth is therefore necessary for determining appropriate reference conditions for river management planning. Results from this multi-season study will provide the base for future work in quantifying temporal changes to patch shape in addition to quantifying the organisation of patches within the channel.

Inventing a co-axial atomic resolution patch clamp to study a single resonating protein complex and ultra-low power communication deep inside a living neuron cell.

PubMed

Ghosh, Subrata; Sahu, Satyajit; Agrawal, Lokesh; Shiga, Takashi; Bandyopadhyay, Anirban

2016-12-01

To read the signals of single molecules in vitro on a surface, or inside a living cell or organ, we introduce a coaxial atom tip (coat) and a coaxial atomic patch clamp (COAPAP). The metal-insulator-metal cavity of these probes extends to the atomic scale (0.1[Formula: see text]nm), it eliminates the cellular or environmental noise with a S/N ratio 10 5 . Five ac signals are simultaneously applied during a measurement by COAT and COAPAP to shield a true signal under environmental noise in five unique ways. The electromagnetic drive in the triaxial atomic tips is specifically designed to sense anharmonic vibrational and transmission signals for any system between 0.1[Formula: see text]nm and 50[Formula: see text]nm where the smallest nanopatch clamp cannot reach. COAT and COAPAP reliably pick up the atomic scale vibrations under the extreme noise of a living cell. Each protein's distinct electromagnetic, mechanical, electrical and ionic vibrational signature studied in vitro in a protected environment is found to match with the ones studied inside a live neuron. Thus, we could confirm that by using our probe blindly we could hold on to a single molecule or its complex in the invisible domain of a living cell. Our decade long investigations on perfecting the tools to measure bio-resonance of all forms and simultaneously in all frequency domains are summarized. It shows that the ratio of emission to absorption resonance frequencies of a biomaterial is around [Formula: see text], only a few in the entire em spectrum are active that regulates all other resonances, like mechanical, ionic, etc.

Direct demonstration of persistent Na+ channel activity in dendritic processes of mammalian cortical neurones

PubMed Central

Magistretti, Jacopo; Ragsdale, David S; Alonso, Angel

1999-01-01

Single Na+ channel activity was recorded in patch-clamp, cell-attached experiments performed on dendritic processes of acutely isolated principal neurones from rat entorhinal-cortex layer II. The distances of the recording sites from the soma ranged from ≈20 to ≈100 μm.Step depolarisations from holding potentials of −120 to −100 mV to test potentials of −60 to +10 mV elicited Na+ channel openings in all of the recorded patches (n= 16).In 10 patches, besides transient Na+ channel openings clustered within the first few milliseconds of the depolarising pulses, prolonged and/or late Na+ channel openings were also regularly observed. This ‘persistent’ Na+ channel activity produced net inward, persistent currents in ensemble-average traces, and remained stable over the entire duration of the experiments (≈9 to 30 min).Two of these patches contained <= 3 channels. In these cases, persistent Na+ channel openings could be attributed to the activity of one single channel.The voltage dependence of persistent-current amplitude in ensemble-average traces closely resembled that of whole-cell, persistent Na+ current expressed by the same neurones, and displayed the same characteristic low threshold of activation.Dendritic, persistent Na+ channel openings had relatively high single-channel conductance (≈20 pS), similar to what is observed for somatic, persistent Na+ channels.We conclude that a stable, persistent Na+ channel activity is expressed by proximal dendrites of entorhinal-cortex layer II principal neurones, and can contribute a significant low-threshold, persistent Na+ current to the dendritic processing of excitatory synaptic inputs. PMID:10601494

Low-dose levonorgestrel and ethinyl estradiol patch and pill: a randomized controlled trial.

PubMed

Kaunitz, Andrew M; Portman, David; Westhoff, Carolyn L; Archer, David F; Mishell, Daniel R; Rubin, Arkady; Foegh, Marie

2014-02-01

To compare a new low-dose levonorgestrel and ethinyl estradiol contraceptive patch (Patch) with a combination oral contraceptive (Pill; 100 micrograms levonorgestrel, 20 micrograms ethinyl estradiol) regarding efficacy, safety, compliance, and unscheduled uterine bleeding. Women (17-40 years; body mass index 16-60) were randomized in a 3:1 ratio to one of two groups: Patch only (13 cycles) or Pill (six cycles) followed by Patch (seven cycles). Investigators evaluated adverse events during cycles 2, 4, 6, 9, and 13. Participants recorded drug administration and uterine bleeding on daily diary cards. Compliance was assessed by measuring levonorgestrel and ethinyl estradiol plasma levels. Pearl Index (pregnancies per 100 woman-years) was calculated to evaluate efficacy. Participants (N=1,504) were randomized to Patch (n=1,129) or Pill (n=375). Approximately 30% were obese, more than 40% were racial or ethnic minorities, and more than 55% were new users of hormonal contraceptives. Laboratory-verified noncompliance (undetectable plasma drug levels) was 11% of Patch and 12.6% of Pill users at cycle 6. Pearl Indices (95% confidence intervals) for the intention-to-treat population (cycles 1-6) were 4.45 (2.34-6.57) for Patch and 4.02 (0.50-7.53) for Pill; excluding laboratory-verified noncompliant participants, Pearl Indices were 2.82 (0.98-4.67) for Patch and 3.80 (0.08-7.52) for Pill (differences not statistically significant). Incidence of unscheduled bleeding and incidence and severity of adverse events were similar for both contraceptives (no statistically significant difference). Efficacy and safety of the new contraceptive Patch are comparable to those of a Pill. Laboratory-verified noncompliance and bleeding profile are similar between the two treatments. The Patch was well tolerated. ClinicalTrials.gov, www.clinicaltrials.gov, NCT01181479. I.

Randomized, double-blind, placebo-controlled trial using lidocaine patch 5% in traumatic rib fractures.

PubMed

Ingalls, Nichole K; Horton, Zachary A; Bettendorf, Matthew; Frye, Ira; Rodriguez, Carlos

2010-02-01

The lidocaine patch 5% was developed to treat postherpetic neuralgia. Anecdotal experience at our institution suggests the lidocaine patch 5% decreases narcotic usage in patients with traumatic rib fractures. This trial was developed to define the patch's efficacy. Patients with rib fractures admitted to the trauma service at our Level I trauma center were enrolled and randomized in a 1 to 1 double-blind manner to receive a lidocaine patch 5% or placebo patch. Fifty-eight patients who met the inclusion criteria were enrolled from January 2007 to August 2008. Demographic and clinical information were recorded. The primary outcomes variable was total narcotic use, analyzed using the 1-tailed Mann-Whitney test. The secondary outcomes variables included non-narcotic pain medication, average pain score, pulmonary complications, and length of stay. Significance was defined based on a 1-sided test for the primary outcome and 2-sided tests for other comparisons, at p < 0.05. Thirty-three patients received the lidocaine patch 5% and 25 received the placebo patch. There were no significant differences in age, number of rib fractures, gender, trauma mechanism, preinjury lung disease, smoking history, percent of current smokers, and need for placement of chest tube between the lidocaine patch 5% and placebo groups. There was no difference between the lidocaine patch 5% and placebo groups, respectively, with regard to total IV narcotic usage: median, 0.23 units versus 0.26 units; total oral narcotics: median, 4 units versus 7 units; pain score: 5.6 +/- 0.4 versus 6.0 +/- 0.3 (mean +/- SEM); length of stay: 7.8 +/- 1.1 versus 6.2 +/- 0.7; or percentage of patients with pulmonary complications: 72.7% versus 72.0%. The lidocaine patch 5% does not significantly improve pain control in polytrauma patients with traumatic rib fractures.

Methylisothiazolinone testing at 2000 ppm: a prevalent sensitizer for allergic contact dermatitis.

PubMed

Ham, Kaiya; Posso-De Los Rios, Claudia J; Gooderham, Melinda

2015-01-01

Methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) have been identified as potent allergens. The optimal MI concentration for patch testing for reaction to these agents has not yet been identified, but it has been suggested that testing MI at 2000 ppm may reduce false-negative reactions. The aim of this study was to report allergic reactions to MI and MCI/MI detected in a community dermatology practice setting in Ontario, Canada. The patch test records of patients with suspected allergic contact dermatitis seen between October 2007 and June 2014 were reviewed. We compared positive patch testing before and after December 2011 when a higher MI concentration was used (2000 ppm aqueous) in addition to the baseline series MCI/MI at 100 ppm. A total of 794 patient records were reviewed. There were 38 true-positive reactions to MI or MCI/MI. Of these 38 patients, 26 (68%) were female. We detected an overall increase in the rate of positive patch testing to MCI/MI, MI alone, or both from 3.13% to 7.45% when MI concentration was introduced at 2000 ppm aqueous. Occupational differences existed between sexes. The addition of MI at 2000 ppm to our screening series effectively increased the detection of MI-induced allergic contact dermatitis.

Smart ECG Monitoring Patch with Built-in R-Peak Detection for Long-Term HRV Analysis.

PubMed

Lee, W K; Yoon, H; Park, K S

2016-07-01

Since heart rate variability (HRV) analysis is widely used to evaluate the physiological status of the human body, devices specifically designed for such applications are needed. To this end, we developed a smart electrocardiography (ECG) patch. The smart patch measures ECG using three electrodes integrated into the patch, filters the measured signals to minimize noise, performs analog-to-digital conversion, and detects R-peaks. The measured raw ECG data and the interval between the detected R-peaks can be recorded to enable long-term HRV analysis. Experiments were performed to evaluate the performance of the built-in R-wave detection, robustness of the device under motion, and applicability to the evaluation of mental stress. The R-peak detection results obtained with the device exhibited a sensitivity of 99.29%, a positive predictive value of 100.00%, and an error of 0.71%. The device also exhibited less motional noise than conventional ECG recording, being stable up to a walking speed of 5 km/h. When applied to mental stress analysis, the device evaluated the variation in HRV parameters in the same way as a normal ECG, with very little difference. This device can help users better understand their state of health and provide physicians with more reliable data for objective diagnosis.

Automated patch clamp on mESC-derived cardiomyocytes for cardiotoxicity prediction.

PubMed

Stoelzle, Sonja; Haythornthwaite, Alison; Kettenhofen, Ralf; Kolossov, Eugen; Bohlen, Heribert; George, Michael; Brüggemann, Andrea; Fertig, Niels

2011-09-01

Cardiovascular side effects are critical in drug development and have frequently led to late-stage project terminations or even drug withdrawal from the market. Physiologically relevant and predictive assays for cardiotoxicity are hence strongly demanded by the pharmaceutical industry. To identify a potential impact of test compounds on ventricular repolarization, typically a variety of ion channels in diverse heterologously expressing cells have to be investigated. Similar to primary cells, in vitro-generated stem cell-derived cardiomyocytes simultaneously express cardiac ion channels. Thus, they more accurately represent the native situation compared with cell lines overexpressing only a single type of ion channel. The aim of this study was to determine if stem cell-derived cardiomyocytes are suited for use in an automated patch clamp system. The authors show recordings of cardiac ion currents as well as action potential recordings in readily available stem cell-derived cardiomyocytes. Besides monitoring inhibitory effects of reference compounds on typical cardiac ion currents, the authors revealed for the first time drug-induced modulation of cardiac action potentials in an automated patch clamp system. The combination of an in vitro cardiac cell model with higher throughput patch clamp screening technology allows for a cost-effective cardiotoxicity prediction in a physiologically relevant cell system.

Buccal patches of atenolol formulated using fenugreek (Trigonella foenum-graecum L.) seed mucilage.

PubMed

Adhikari, Surya Narayan Ratha; Panda, Satyabrata

2017-01-01

The use of mucoadhesive natural polymers in designing mucoadhesive patch systems has received much attention. The study involved the development and evaluation of buccal patches of atenolol using fenugreek (Trigonella foenum-graecum L.) seed mucilage with hydroxylpropyl methyl cellulose (HPMC K4M) and a backing membrane (ethyl cellulose 5% w/v). These atenolol-releasing buccal patches were prepared using a solvent casting technique. The buccal patches prepared were evaluated for average weight, thickness, drug content, folding endurance and moisture content. Ex vivo mucoadhesive strength, force of adhesion and bonding strength were determined using porcine buccal mucosa. The mucosal permeation of atenolol through the porcine buccal mucosa was carried out using a Franz diffusion cell in phosphate buffer saline, pH 6.8. These buccal patches were also characterized by SEM and FTIR spectroscopy. The average weight, thickness, drug content, folding endurance and moisture content of these atenolol-releasing buccal patches were found satisfactory for all the patches. Amongst all, the F-4 buccal patch showed maximum mucoadhesive strength (31.12 ±1.86 g), force of adhesion (30.53 × 10-2 N) and bond strength (1748.89 N/m2). Ex vivo atenolol permeation from the buccal patches showed drug permeation across the excised porcine buccal mucosa over 12 h. The F-4 buccal patch showed maximum permeation flux (29.12 μg/cm2/h). The developed atenolol-releasing buccal patches can be beneficial over the conventional drug delivery systems to decrease the dosing frequency and enhance patient compliance.

Computer generated holographic microtags

DOEpatents

Sweatt, W.C.

1998-03-17

A microlithographic tag comprising an array of individual computer generated holographic patches having feature sizes between 250 and 75 nanometers is disclosed. The tag is a composite hologram made up of the individual holographic patches and contains identifying information when read out with a laser of the proper wavelength and at the proper angles of probing and reading. The patches are fabricated in a steep angle Littrow readout geometry to maximize returns in the -1 diffracted order. The tags are useful as anti-counterfeiting markers because of the extreme difficulty in reproducing them. 5 figs.

Bamboo thickets alter the demographic structure of Euterpe edulis population: A keystone, threatened palm species of the Atlantic forest

NASA Astrophysics Data System (ADS)

Rother, Débora Cristina; Rodrigues, Ricardo Ribeiro; Pizo, Marco Aurélio

2016-01-01

The rapid spread of bamboos can strongly affect forest structure by interfering plant regeneration and reducing local biodiversity. Considering that bamboos exert a negative influence on the plant community, our main goal was to investigate how this influence manifests at the population level. We compared the demographic structure of the threatened palm Euterpe edulis between bamboo and non-bamboo dominated patches within the Atlantic forest. In the study site, the native bamboo Guadua tagoara has created a marked patchiness and heterogeneity in the vegetation. Plots were set up randomly in bamboo and non-bamboo patches and the heights of all E. edulis individuals were measured. Data from canopy openness and litter depth were collected for both patches. Greater number of E. edulis was recorded in bamboo patches. However, frequency distribution of the height classes differed between patches revealing a predominance of seedling and sapling I classes in bamboo patches, in comparison to a more evenly distribution of height classes in non-bamboo patches. The canopy in bamboo patches was more open and the litter depth was thicker. Our analyses evidenced G. tagoara is functioning as a demographic bottleneck of natural population of E. edulis by arresting its later stages of regeneration and in high densities that bamboos may limit recruitment of this palm species.

Femoral graft-tunnel angles in posterior cruciate ligament reconstruction: analysis with 3-dimensional models and cadaveric experiments.

PubMed

Kim, Sung-Jae; Chun, Yong-Min; Kim, Sung-Hwan; Moon, Hong-Kyo; Jang, Jae-Won

2013-07-01

The purpose of this study was to compare four graft-tunnel angles (GTA), the femoral GTA formed by three different femoral tunneling techniques (the outside-in, a modified inside-out technique in the posterior sag position with knee hyperflexion, and the conventional inside-out technique) and the tibia GTA in 3-dimensional (3D) knee flexion models, as well as to examine the influence of femoral tunneling techniques on the contact pressure between the intra-articular aperture of the femoral tunnel and the graft. Twelve cadaveric knees were tested. Computed tomography scans were performed at different knee flexion angles (0°, 45°, 90°, and 120°). Femoral and tibial GTAs were measured at different knee flexion angles on the 3D knee models. Using pressure sensitive films, stress on the graft of the angulation of the femoral tunnel aperture was measured in posterior cruciate ligament reconstructed cadaveric knees. Between 45° and 120° of knee flexion, there were no significant differences between the outside-in and modified inside-out techniques. However, the femoral GTA for the conventional inside-out technique was significantly less than that for the other two techniques (p<0.001). In cadaveric experiments using pressure-sensitive film, the maximum contact pressure for the modified inside-out and outside-in technique was significantly lower than that for the conventional inside-out technique (p=0.024 and p=0.017). The conventional inside-out technique results in a significantly lesser GTA and higher stress at the intra-articular aperture of the femoral tunnel than the outside-in technique. However, the results for the modified inside-out technique are similar to those for the outside-in technique.

[Continued Use of Rotigotine Transdermal Patches for Parkinson Disease].

PubMed

Yasutaka, Yuki; Fujioka, Shinsuke; Shibaguchi, Hirotomo; Imakyure, Osamu; Washiyama, Atsushi; Tsuboi, Yoshio; Futagami, Koujiro

2016-06-01

Transdermal patches containing rotigotine, a dopamine agonist (DA) for treatment of Parkinson disease, continuously exert stable effects when applied once daily. Therefore, they are expected to reduce the patient burdens due to complications such as wearing-off and dysphagia. However, dosing is occasionally reduced or discontinued after application because of several reasons such as skin reactions or unsatisfactory efficacy. To identify the risk factors involved in the reduced or discontinued use of rotigotine patches, a retrospective study was conducted with reference to the medical records of patients with Parkinson disease who received rotigotine patches in our hospital. 85 patients were involved in this study. Dosing of rotigotine was reduced or discontinued in 53 patients during the study period. The factors associated with charges in treatment included combination therapy with clonazepam and oral administration of another DA before the application of rotigotine. The reduction or discontinuation rate of rotigotine patches in patients who reduced the equivalent dose of DA on the introduction of rotigotine patches was 94.7%, showing a significantly higher rate compared with 61.3% in the increased dose group. To improve adherence to rotigotine patch therapy, physicians need to carefully consider concomitant drugs and total dose of DAs. (Received December 7, 2015; Accepted February 22, 2016; Published June 1, 2016).

Adenosine triphosphate regulates the activity of guinea pig Cav1.2 channel by direct binding to the channel in a dose-dependent manner.

PubMed

Feng, Rui; Xu, Jianjun; Minobe, Etsuko; Kameyama, Asako; Yang, Lei; Yu, Lifeng; Hao, Liying; Kameyama, Masaki

2014-05-01

The present study is to investigate the mechanism by which ATP regulates Cav1.2 channel activity. Ventricular tissue was obtained from adult guinea pig hearts using collagenase. Ca(2+) channel activity was monitored using the patch-clamp technique. Proteins were purified using wheat germ agglutinin-Sepharose, and the concentration was determined using the Coomassie brilliant blue technique. ATP binding to the Cav1.2 channel was examined using the photoaffinity method. EDA-ATP-biotin maintains Ca(2+) channel activity in inside-out membrane patches. ATP directly bound to the Cav1.2 channel in a dose-dependent manner, and at least two molecules of ATP bound to one molecule of the Cav1.2 channel. Low levels of calmodulin (CaM) increased ATP binding to the Cav1.2 channel, but higher levels of CaM decreased ATP binding to the Cav1.2 channel. In addition, Ca(2+) was another regulator for ATP binding to the Cav1.2 channel. Furthermore, ATP bound to GST-fusion peptides of NH2-terminal region (amino acids 6-140) and proximal COOH-terminal region (amino acids 1,509-1,789) of the main subunit (α1C) of the Cav1.2 channel. Our data suggest that ATP might regulate Cav1.2 channel activity by directly binding to the Cav1.2 channel in a dose-dependent manner. In addition, the ATP-binding effect to the Cav1.2 channel was both CaM- and Ca(2+) dependent.

Phloem-localized, proton-coupled sucrose carrier ZmSUT1 mediates sucrose efflux under the control of the sucrose gradient and the proton motive force.

PubMed

Carpaneto, Armando; Geiger, Dietmar; Bamberg, Ernst; Sauer, Norbert; Fromm, Jörg; Hedrich, Rainer

2005-06-03

The phloem network is as essential for plants as the vascular system is for humans. This network, assembled by nucleus- and vacuole-free interconnected living cells, represents a long distance transport pathway for nutrients and information. According to the Münch hypothesis, osmolytes such as sucrose generate the hydrostatic pressure that drives nutrient and water flow between the source and the sink phloem (Münch, E. (1930) Die Stoffbewegungen in der Pflanze, Gustav Fischer, Jena, Germany). Although proton-coupled sucrose carriers have been localized to the sieve tube and the companion cell plasma membrane of both source and sink tissues, knowledge of the molecular representatives and the mechanism of the sucrose phloem efflux is still scant. We expressed ZmSUT1, a maize sucrose/proton symporter, in Xenopus oocytes and studied the transport characteristics of the carrier by electrophysiological methods. Using the patch clamp techniques in the giant inside-out patch mode, we altered the chemical and electrochemical gradient across the sucrose carrier and analyzed the currents generated by the proton flux. Thereby we could show that ZmSUT1 is capable of mediating both the sucrose uptake into the phloem in mature leaves (source) as well as the desorption of sugar from the phloem vessels into heterotrophic tissues (sink). As predicted from a perfect molecular machine, the ZmSUT1-mediated sucrose-coupled proton current was reversible and depended on the direction of the sucrose and pH gradient as well as the membrane potential across the transporter.

A comparison of serotonin neuromodulation of mouse spinal V2a interneurons using perforated patch and whole cell recording techniques

PubMed Central

Dietz, Shelby; Husch, Andreas; Harris-Warrick, Ronald M.

2012-01-01

Whole cell recordings (WCRs) are frequently used to study neuronal properties, but may be problematic when studying neuromodulatory responses, due to dialysis of the cell's cytoplasm. Perforated patch recordings (PPR) avoid cellular dialysis and might reveal additional modulatory effects that are lost during WCR. We have previously used WCR to characterize the responses of the V2a class of Chx10-expressing neurons to serotonin (5-HT) in the neonatal mouse spinal cord (Zhong et al., 2010). Here we directly compare multiple aspects of the responses to 5-HT using WCR and PPR in Chx10-eCFP neurons in spinal cord slices from 2 to 4 day old mice. Cellular properties recorded in PPR and WCR were similar, but high-quality PP recordings could be maintained for significantly longer. Both WCR and PPR cells could respond to 5-HT, and although neurons recorded by PPR showed a significantly greater response to 5-HT in some parameters, the absolute differences between PPR and WCR were small. We conclude that WCR is an acceptable recording method for short-term recordings of neuromodulatory effects, but the less invasive PPR is preferable for detailed analyses and is necessary for stable recordings lasting an hour or more. PMID:23060747

A Stretchable Radio-Frequency Strain Sensor Using Screen Printing Technology

PubMed Central

Jeong, Heijun; Lim, Sungjoon

2016-01-01

In this paper, we propose a stretchable radio-frequency (RF) strain sensor fabricated with screen printing technology. The RF sensor is designed using a half-wavelength patch that resonates at 3.7 GHz. The resonant frequency is determined by the length of the patch, and it therefore changes when the patch is stretched. Polydimethylsiloxane (PDMS) is used to create the substrate, because of its stretchable and screen-printable surface. In addition, Dupont PE872 (Dupont, NC, American) silver conductive ink is used to create the stretchable conductive patterns. The sensor performance is demonstrated both with full-wave simulations and with measurements carried out on a fabricated sample. When the length of the patch sensor is increased by a 7.8% stretch, the resonant frequency decreases from 3.7 GHz to 3.43 GHz, evidencing a sensitivity of 3.43 × 107 Hz/%. Stretching the patch along its width does not change the resonant frequency. PMID:27827833

Patch test standard series recommended by the Brazilian Contact Dermatitis Study Group during the 2006-2011 period.

PubMed

Duarte, Ida Alzira Gomes; Tanaka, Greta Merie; Suzuki, Nathalie Mie; Lazzarini, Rosana; Lopes, Andressa Sato de Aquino; Volpini, Beatrice Mussio Fornazier; Castro, Paulo Carrara de

2013-01-01

A retrospective study was carried out between 2006-2011. Six hundred and eighteen patients with suspected allergic contact dermatitis underwent the standard patch test series recommended by the Brazilian Contact Dermatitis Research Group. The aim of our study was to evaluate the variation of positive patch-test results from standard series year by year. The most frequently positive allergens were: nickel sulfate, thimerosal and potassium bichromate. Decrease of positive patch-test results over the years was statistically significant for: lanolin (p=0.01), neomycin (p=0.01) and anthraquinone (p=0.04). A follow-up study should be useful in determining which allergens could be excluded from standard series, as they may represent low sensitization risk.

Combination of High-density Microelectrode Array and Patch Clamp Recordings to Enable Studies of Multisynaptic Integration.

PubMed

Jäckel, David; Bakkum, Douglas J; Russell, Thomas L; Müller, Jan; Radivojevic, Milos; Frey, Urs; Franke, Felix; Hierlemann, Andreas

2017-04-20

We present a novel, all-electric approach to record and to precisely control the activity of tens of individual presynaptic neurons. The method allows for parallel mapping of the efficacy of multiple synapses and of the resulting dynamics of postsynaptic neurons in a cortical culture. For the measurements, we combine an extracellular high-density microelectrode array, featuring 11'000 electrodes for extracellular recording and stimulation, with intracellular patch-clamp recording. We are able to identify the contributions of individual presynaptic neurons - including inhibitory and excitatory synaptic inputs - to postsynaptic potentials, which enables us to study dendritic integration. Since the electrical stimuli can be controlled at microsecond resolution, our method enables to evoke action potentials at tens of presynaptic cells in precisely orchestrated sequences of high reliability and minimum jitter. We demonstrate the potential of this method by evoking short- and long-term synaptic plasticity through manipulation of multiple synaptic inputs to a specific neuron.

Perforated Patch-clamp Recording of Mouse Olfactory Sensory Neurons in Intact Neuroepithelium: Functional Analysis of Neurons Expressing an Identified Odorant Receptor

PubMed Central

Jarriault, David; Grosmaitre, Xavier

2015-01-01

Analyzing the physiological responses of olfactory sensory neurons (OSN) when stimulated with specific ligands is critical to understand the basis of olfactory-driven behaviors and their modulation. These coding properties depend heavily on the initial interaction between odor molecules and the olfactory receptor (OR) expressed in the OSNs. The identity, specificity and ligand spectrum of the expressed OR are critical. The probability to find the ligand of the OR expressed in an OSN chosen randomly within the epithelium is very low. To address this challenge, this protocol uses genetically tagged mice expressing the fluorescent protein GFP under the control of the promoter of defined ORs. OSNs are located in a tight and organized epithelium lining the nasal cavity, with neighboring cells influencing their maturation and function. Here we describe a method to isolate an intact olfactory epithelium and record through patch-clamp recordings the properties of OSNs expressing defined odorant receptors. The protocol allows one to characterize OSN membrane properties while keeping the influence of the neighboring tissue. Analysis of patch-clamp results yields a precise quantification of ligand/OR interactions, transduction pathways and pharmacology, OSNs' coding properties and their modulation at the membrane level.  PMID:26275097

Assessment of optimal strategies in a two-patch dengue transmission model with seasonality

PubMed Central

Lee, Chang Hyeong; Lee, Sunmi

2017-01-01

Emerging and re-emerging dengue fever has posed serious problems to public health officials in many tropical and subtropical countries. Continuous traveling in seasonally varying areas makes it more difficult to control the spread of dengue fever. In this work, we consider a two-patch dengue model that can capture the movement of host individuals between and within patches using a residence-time matrix. A previous two-patch dengue model without seasonality is extended by adding host demographics and seasonal forcing in the transmission rates. We investigate the effects of human movement and seasonality on the two-patch dengue transmission dynamics. Motivated by the recent Peruvian dengue data in jungle/rural areas and coast/urban areas, our model mimics the seasonal patterns of dengue outbreaks in two patches. The roles of seasonality and residence-time configurations are highlighted in terms of the seasonal reproduction number and cumulative incidence. Moreover, optimal control theory is employed to identify and evaluate patch-specific control measures aimed at reducing dengue prevalence in the presence of seasonality. Our findings demonstrate that optimal patch-specific control strategies are sensitive to seasonality and residence-time scenarios. Targeting only the jungle (or endemic) is as effective as controlling both patches under weak coupling or symmetric mobility. However, focusing on intervention for the city (or high density areas) turns out to be optimal when two patches are strongly coupled with asymmetric mobility. PMID:28301523

Cancer Seeding Risk from an Epidural Blood Patch in Patients with Leukemia or Lymphoma.

PubMed

Demaree, Christopher J; Soliz, Jose M; Gebhardt, Rodolfo

2017-04-01

Lumber punctures are a common procedure in patients with cancer. However, a potential complication of a lumbar puncture is a postdural puncture headache. The risk of neoplastic seeding to the central nervous system has led to concern over performing epidural blood patches (EBPs) for the treatment of postdural puncture headaches in patients with cancer. The goal of this retrospective study was to evaluate cancer seeding in the central nervous system in patients diagnosed with leukemia or lymphoma. Institutional electronic records were queried over a 13-year period from 2000 to 2013 for patients with leukemia and/or lymphoma and who received at least one EBP. Demographic and procedural data, cancer treatments, and mortality were all examined. Patient records were reviewed for evidence of new-onset neoplastic central nervous system seeding after an epidural blood patch. A total of 80 patients were identified for review. Eighteen patients had a diagnosis of leukemia, and 62 had lymphoma. Following an EBP, none of the patients experienced new cancer or cancer seeding in the central nervous system following an epidural blood patch at a median follow-up of 3.74 years. Though the risks of EBP in the cancer patient population have been hypothesized, no previous studies have assessed the risk of seeding cancer to the central nervous system. Based on our results, an epidural blood patch bears low risk of cancer seeding when used to treat postdural puncture headache that is unresponsive to conservative treatments. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Enhanced Monitoring of Nanosecond Electric Pulse-Evoked Membrane Conductance Changes in Whole-Cell Patch Clamp Experiments.

PubMed

Yoon, Jihwan; Leblanc, Normand; Zaklit, Josette; Vernier, P Thomas; Chatterjee, Indira; Craviso, Gale L

2016-10-01

Patch clamp electrophysiology serves as a powerful method for studying changes in plasma membrane ion conductance induced by externally applied high-intensity nanosecond electric pulses (NEPs). This paper describes an enhanced monitoring technique that minimizes the length of time between pulse exposure and data recording in a patch-clamped excitable cell. Whole-cell membrane currents were continuously recorded up to 11 ms before and resumed 8 ms after delivery of a 5-ns, 6 MV/m pulse by a pair of tungsten rod electrodes to a patched adrenal chromaffin cell maintained at a holding potential of -70 mV. This timing was achieved by two sets of relay switches. One set was used to disconnect the patch pipette electrode from the pre-amplifier and connect it to a battery to maintain membrane potential at -70 mV, and also to disconnect the reference electrode from the amplifier. The other set was used to disconnect the electrodes from the pulse generator until the time of NEP/sham exposure. The sequence and timing of both sets of relays were computer-controlled. Using this procedure, we observed that a 5-ns pulse induced an instantaneous inward current that decayed exponentially over the course of several minutes, that a second pulse induced a similar response, and that the current was carried, at least in part, by Na + . This approach for characterizing ion conductance changes in an excitable cell in response to NEPs will yield information essential for assessing the potential use of NEP stimulation for therapeutic applications.

Heterogeneous neuronal firing patterns during interictal epileptiform discharges in the human cortex

PubMed Central

Keller, Corey J.; Truccolo, Wilson; Gale, John T.; Eskandar, Emad; Thesen, Thomas; Carlson, Chad; Devinsky, Orrin; Kuzniecky, Ruben; Doyle, Werner K.; Madsen, Joseph R.; Schomer, Donald L.; Mehta, Ashesh D.; Brown, Emery N.; Hochberg, Leigh R.; Ulbert, István; Halgren, Eric

2010-01-01

Epileptic cortex is characterized by paroxysmal electrical discharges. Analysis of these interictal discharges typically manifests as spike–wave complexes on electroencephalography, and plays a critical role in diagnosing and treating epilepsy. Despite their fundamental importance, little is known about the neurophysiological mechanisms generating these events in human focal epilepsy. Using three different systems of microelectrodes, we recorded local field potentials and single-unit action potentials during interictal discharges in patients with medically intractable focal epilepsy undergoing diagnostic workup for localization of seizure foci. We studied 336 single units in 20 patients. Ten different cortical areas and the hippocampus, including regions both inside and outside the seizure focus, were sampled. In three of these patients, high density microelectrode arrays simultaneously recorded between 43 and 166 single units from a small (4 mm × 4 mm) patch of cortex. We examined how the firing rates of individual neurons changed during interictal discharges by determining whether the firing rate during the event was the same, above or below a median baseline firing rate estimated from interictal discharge-free periods (Kruskal–Wallis one-way analysis, P<0.05). Only 48% of the recorded units showed such a modulation in firing rate within 500 ms of the discharge. Units modulated during the discharge exhibited significantly higher baseline firing and bursting rates than unmodulated units. As expected, many units (27% of the modulated population) showed an increase in firing rate during the fast segment of the discharge (±35 ms from the peak of the discharge), while 50% showed a decrease during the slow wave. Notably, in direct contrast to predictions based on models of a pure paroxysmal depolarizing shift, 7.7% of modulated units recorded in or near the seizure focus showed a decrease in activity well ahead (0–300 ms) of the discharge onset, while 12.2% of units increased in activity in this period. No such pre-discharge changes were seen in regions well outside the seizure focus. In many recordings there was also a decrease in broadband field potential activity during this same pre-discharge period. The different patterns of interictal discharge-modulated firing were classified into more than 15 different categories. This heterogeneity in single unit activity was present within small cortical regions as well as inside and outside the seizure onset zone, suggesting that interictal epileptiform activity in patients with epilepsy is not a simple paroxysm of hypersynchronous excitatory activity, but rather represents an interplay of multiple distinct neuronal types within complex neuronal networks. PMID:20511283

Economic feasibility of producing inside-out beams from small-diameter logs

Treesearch

David W. Patterson; Richard A. Kluender; James E. Granskog

2002-01-01

Previous work has shown that it is technically feasible to produce inside-out (ISO) beams by taking small-diameter (5 to 7 in.) logs, slabbing four sides, quartering the cant, and turning the quarters inside out and gluing them together. After drying, the beams were found to be straight, with no cracks, and of equal or better mechanical properties than solid sawn...

Is Decellularized Porcine Small Intestine Sub-mucosa Patch Suitable for Aortic Arch Repair?

PubMed Central

Corno, Antonio F.; Smith, Paul; Bezuska, Laurynas; Mimic, Branko

2018-01-01

Introduction: We reviewed our experience with decellularized porcine small intestine sub-mucosa (DPSIS) patch, recently introduced for congenital heart defects. Materials and Methods: Between 10/2011 and 04/2016 a DPSIS patch was used in 51 patients, median age 1.1 months (5 days to 14.5 years), for aortic arch reconstruction (45/51 = 88.2%) or aortic coarctation repair (6/51 = 11.8%). All medical records were retrospectively reviewed, with primary endpoints interventional procedure (balloon dilatation) or surgery (DPSIS patch replacement) due to patch-related complications. Results: In a median follow-up time of 1.5 ± 1.1 years (0.6–2.3years) in 13/51 patients (25.5%) a re-intervention, percutaneous interventional procedure (5/51 = 9.8%) or re-operation (8/51 = 15.7%) was required because of obstruction in the correspondence of the DPSIS patch used to enlarge the aortic arch/isthmus, with median max velocity flow at Doppler interrogation of 4.0 ± 0.51 m/s. Two patients required surgery after failed interventional cardiology. The mean interval between DPSIS patch implantation and re-intervention (percutaneous procedure or re-operation) was 6 months (1–17 months). While there were 3 hospital deaths (3/51 = 5.9%) not related to the patch implantation, no early or late mortality occurred for the subsequent procedure required for DPSIS patch interventional cardiology or surgery. The median max velocity flow at Doppler interrogation through the aortic arch/isthmus for the patients who did not require interventional procedure or surgery was 1.7 ± 0.57 m/s. Conclusions: High incidence of re-interventions with DPSIS patch for aortic arch and/or coarctation forced us to use alternative materials (homografts and decellularized gluteraldehyde preserved bovine pericardial matrix). PMID:29900163

Simultaneous multi-patch-clamp and extracellular-array recordings: Single neuron reflects network activity

NASA Astrophysics Data System (ADS)

Vardi, Roni; Goldental, Amir; Sardi, Shira; Sheinin, Anton; Kanter, Ido

2016-11-01

The increasing number of recording electrodes enhances the capability of capturing the network’s cooperative activity, however, using too many monitors might alter the properties of the measured neural network and induce noise. Using a technique that merges simultaneous multi-patch-clamp and multi-electrode array recordings of neural networks in-vitro, we show that the membrane potential of a single neuron is a reliable and super-sensitive probe for monitoring such cooperative activities and their detailed rhythms. Specifically, the membrane potential and the spiking activity of a single neuron are either highly correlated or highly anti-correlated with the time-dependent macroscopic activity of the entire network. This surprising observation also sheds light on the cooperative origin of neuronal burst in cultured networks. Our findings present an alternative flexible approach to the technique based on a massive tiling of networks by large-scale arrays of electrodes to monitor their activity.

Simultaneous multi-patch-clamp and extracellular-array recordings: Single neuron reflects network activity.

PubMed

Vardi, Roni; Goldental, Amir; Sardi, Shira; Sheinin, Anton; Kanter, Ido

2016-11-08

The increasing number of recording electrodes enhances the capability of capturing the network's cooperative activity, however, using too many monitors might alter the properties of the measured neural network and induce noise. Using a technique that merges simultaneous multi-patch-clamp and multi-electrode array recordings of neural networks in-vitro, we show that the membrane potential of a single neuron is a reliable and super-sensitive probe for monitoring such cooperative activities and their detailed rhythms. Specifically, the membrane potential and the spiking activity of a single neuron are either highly correlated or highly anti-correlated with the time-dependent macroscopic activity of the entire network. This surprising observation also sheds light on the cooperative origin of neuronal burst in cultured networks. Our findings present an alternative flexible approach to the technique based on a massive tiling of networks by large-scale arrays of electrodes to monitor their activity.

Simultaneous multi-patch-clamp and extracellular-array recordings: Single neuron reflects network activity

PubMed Central

Vardi, Roni; Goldental, Amir; Sardi, Shira; Sheinin, Anton; Kanter, Ido

2016-01-01

The increasing number of recording electrodes enhances the capability of capturing the network’s cooperative activity, however, using too many monitors might alter the properties of the measured neural network and induce noise. Using a technique that merges simultaneous multi-patch-clamp and multi-electrode array recordings of neural networks in-vitro, we show that the membrane potential of a single neuron is a reliable and super-sensitive probe for monitoring such cooperative activities and their detailed rhythms. Specifically, the membrane potential and the spiking activity of a single neuron are either highly correlated or highly anti-correlated with the time-dependent macroscopic activity of the entire network. This surprising observation also sheds light on the cooperative origin of neuronal burst in cultured networks. Our findings present an alternative flexible approach to the technique based on a massive tiling of networks by large-scale arrays of electrodes to monitor their activity. PMID:27824075

Organic iron (III) complexing ligands during an iron enrichment experiment in the western subarctic North Pacific

NASA Astrophysics Data System (ADS)

Kondo, Yoshiko; Takeda, Shigenobu; Nishioka, Jun; Obata, Hajime; Furuya, Ken; Johnson, William Keith; Wong, C. S.

2008-06-01

Complexation of iron (III) with natural organic ligands was investigated during a mesoscale iron enrichment experiment in the western subarctic North Pacific (SEEDS II). After the iron infusions, ligand concentrations increased rapidly with subsequent decreases. While the increases of ligands might have been partly influenced by amorphous iron colloids formation (12-29%), most in-situ increases were attributable to the <200 kDa fraction. Dilution of the fertilized patch may have contributed to the rapid decreases of the ligands. During the bloom decline, ligand concentration increased again, and the high concentrations persisted for 10 days. The conditional stability constant was not different between inside and outside of the fertilized patch. These results suggest that the chemical speciation of the released iron was strongly affected by formation of the ligands; the production of ligands observed during the bloom decline will strongly impact the iron cycle and bioavailability in the surface water.

Habitat corridors function as both drift fences and movement conduits for dispersing flies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fried, Joanna H.; Levey Douglas J.; Hogsette, Jerome A.

2005-03-30

Abstract Corridors connect otherwise isolated habitat patches and can direct movement of animals among such patches. In eight experimental landscapes, we tested two hypotheses of how corridors might affect dispersal behavior. The Traditional Corridor hypothesis posits that animals preferentially leave patches via corridors, following them into adjacent patches. The Drift Fence hypothesis posits that animals dispersing through matrix habitat are diverted into patches with corridors because they follow corridors when encountered. House flies (Musca domestica L.), a species that prefers the habitat of our patches and corridors, were released in a central patch (100•100 m) and recaptured in peripheral patchesmore » that were or were not connected by a corridor. Flies were captured more frequently in connected than unconnected patches, thereby supporting the Traditional Corridor hypothesis. The Drift Fence hypothesis was also supported, as flies were captured more frequently in unconnected patches with blind (dead end) corridors than in unconnected patches of equal area without blind corridors. A second experiment tested whether these results might be dependent on the type of patch-matrix boundary encountered by dispersing flies and whether edge-following behavior might be the mechanism underlying the observed corridor effect in the first experiment. We recorded dispersal patterns of flies released along forest edges with dense undergrowth in the forest (‘‘closed’’ edges) and along edges with little forest understory (‘‘open’’ edges). Flies were less likely to cross and more likely to follow closed edges than open edges, indicating that when patch and corridor edges are pronounced, edge-following behavior of flies may direct them along corridors into connected patches. Because edges in the first experiment were open, these results also suggest that corridor effects for flies in that experiment would have been even stronger if the edges around the source patches and corridors had been more closed. Taken together, our results suggest that corridors can affect dispersal of organisms in unappreciated ways (i.e., as drift fences) and that edge type can alter dispersal behavior.« less

LABONFOIL: investigations regarding microfluidic skin patches for drug detection using flexible OLEDs

NASA Astrophysics Data System (ADS)

Scholles, M.; Kroker, L.; Vogel, U.; Krüger, J.; Walczak, R.; Ruano-Lopez, J.

2010-02-01

This contribution describes first results concerning the overall and especially optical system design of microfluidic skin patches for drug detection based on fluorescence analysis of sweat samples. This work has been carried out within the European project LABONFOIL which aims to develop low-cost lab-on-chip systems for four different applications, one of them for the detection of cocaine abuse by professional drivers. To date work has focused on the integrated design of the skin patch itself including methods for sweat collection as well as studies concerning the feasibility of OLEDs for optical excitation of the fluorescence signal.

Strategies for mapping synaptic inputs on dendrites in vivo by combining two-photon microscopy, sharp intracellular recording, and pharmacology

PubMed Central

Levy, Manuel; Schramm, Adrien E.; Kara, Prakash

2012-01-01

Uncovering the functional properties of individual synaptic inputs on single neurons is critical for understanding the computational role of synapses and dendrites. Previous studies combined whole-cell patch recording to load neurons with a fluorescent calcium indicator and two-photon imaging to map subcellular changes in fluorescence upon sensory stimulation. By hyperpolarizing the neuron below spike threshold, the patch electrode ensured that changes in fluorescence associated with synaptic events were isolated from those caused by back-propagating action potentials. This technique holds promise for determining whether the existence of unique cortical feature maps across different species may be associated with distinct wiring diagrams. However, the use of whole-cell patch for mapping inputs on dendrites is challenging in large mammals, due to brain pulsations and the accumulation of fluorescent dye in the extracellular milieu. Alternatively, sharp intracellular electrodes have been used to label neurons with fluorescent dyes, but the current passing capabilities of these high impedance electrodes may be insufficient to prevent spiking. In this study, we tested whether sharp electrode recording is suitable for mapping functional inputs on dendrites in the cat visual cortex. We compared three different strategies for suppressing visually evoked spikes: (1) hyperpolarization by intracellular current injection, (2) pharmacological blockade of voltage-gated sodium channels by intracellular QX-314, and (3) GABA iontophoresis from a perisomatic electrode glued to the intracellular electrode. We found that functional inputs on dendrites could be successfully imaged using all three strategies. However, the best method for preventing spikes was GABA iontophoresis with low currents (5–10 nA), which minimally affected the local circuit. Our methods advance the possibility of determining functional connectivity in preparations where whole-cell patch may be impractical. PMID:23248588

Identification of critical amino acids in the proximal C-terminal of TREK-2 K+ channel for activation by acidic pHi and ATP-dependent inhibition.

PubMed

Woo, Joohan; Jun, Young Keul; Zhang, Yin-Hua; Nam, Joo Hyun; Shin, Dong Hoon; Kim, Sung Joon

2018-02-01

TWIK-related two-pore domain K + channels (TREKs) are regulated by intracellular pH (pH i ) and Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P 2 ). Previously, Glu 306 in proximal C-terminal (pCt) of mouse TREK-1 was identified as the pH i -sensing residue. The direction of PI(4,5)P 2 sensitivity is controversial, and we have recently shown that TREKs are inhibited by intracellular ATP via endogenous PI(4,5)P 2 formation. Here we investigate the anionic and cationic residues of pCt for the pH i and ATP-sensitivity in human TREK-2 (hTREK-2). In inside-out patch clamp recordings (I TREK-2,i-o ), acidic pH i -induced activation was absent in E332A and was partly attenuated in E335A. Neutralization of cationic Lys (K330A) also eliminated the acidic pH i sensitivity of I TREK-2,i-o . Unlike the inhibition of wild-type (WT) I TREK-2,i-o by intracellular ATP, neither E332A nor K330A was sensitive to ATP. Nevertheless, exogenous PI(4,5)P 2 (10 μM) abolished I TREK-2 i-o in all the above mutants as well as in WT, indicating unspecific inhibition by exogenous PI(4,5)P 2 . In whole-cell recordings of TREK-2 (I TREK-2,w-c ), K330A and E332A showed higher or fully active basal activity, showing attenuated or insignificant activation by 2-APB, arachidonic acid, or acidic pH e 6.9. I TREK-1,w-c of WT is largely suppressed by pH e 6.9, and the inhibition is slightly attenuated in K312A and E315A. The results show concerted roles of the oppositely charged Lys and Glu in pCt for the ATP-dependent low basal activity and pH i sensitivity.

Modeling Flue Pipes: Subsonic Flow, Lattice Boltzmann, and Parallel Distributed Computers.

DTIC Science & Technology

1995-01-01

Abstract The problem of simulating the hydrodynamics and the acoustic waves inside wind musical instruments such as the recorder, the organ, and the ute...inside wind musical instruments such as the recorder, the organ, and the ute is considered. The problem is attacked by developing suitable local...applications such as the simulation of uid dynamics inside wind musical instruments. In the past, he has also worked on numerical methods for ordinary di

Portable Holographic Interferometry Testing System: Application to crack patching quality control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heslehurst, R.B.; Baird, J.P.; Williamson, H.M.

Over recent years the repair of metallic structures has been improved through the use of patches fabricated from composite materials and adhesively bonded to the damaged area. This technology is termed crack patching, and has been successfully and extensively used by the RAAF and the USAF. However, application of the technology to civilian registered aircraft has had limited success due to the apparent lack of suitable quality assurance testing methods and the airworthiness regulators concern overpatch adhesion integrity. Holographic interferometry has previously shown the advantages of detecting out-of-plane deformations of the order of the wavelength of light (1{mu}). Evidence willmore » be presented that holography is able to detect changes in load path due to debonds and weakened adhesion in an adhesively bonded patch. A Portable Holographic Interferometry Testing System (PHITS) which overcomes the vibration isolation problem associated with conventional holography techniques has been developed. The application of PHITS to crack patching technology now provides a suitable method to verify the integrity of bonded patches in-situ.« less

Management of nontraumatic corneal perforation with tectonic drape patch and cyanoacrylate glue.

PubMed

Khalifa, Yousuf M; Bailony, M Rami; Bloomer, Michele M; Killingsworth, Daniel; Jeng, Bennie H

2010-10-01

To report a case of nontraumatic corneal perforation managed with a tectonic drape patch. Interventional case report. A 60-year-old patient with a corneal scar in his left eye likely secondary to herpes simplex virus interstitial keratitis underwent laser peripheral iridotomy for narrow angles. He developed progressive thinning of the cornea overlying the scar that led to a descemetocele and then ultimately a 1.2- × 1.7-mm perforation. Intraoperatively, several attempts were made to seal the perforation with cyanoacrylate glue, but the wound continued to leak. Sterile plastic drape that was on the surgical field was fashioned into a 2-mm-diameter patch, and the peripheral edge of the tectonic drape patch was glued over the perforation, successfully sealing the cornea. One week later, the drape patch was intact without leak, and a penetrating keratoplasty was carried out without complication. Tectonic drape patch technique for nontraumatic corneal perforations in which there is tissue loss is a viable temporizing option when cyanoacrylate glue alone fails and when there is no corneal tissue or amniotic membrane available to close the wound.

An integrated platform for simultaneous multi-well field potential recording and Fura-2-based calcium transient ratiometry in human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes.

PubMed

Rast, Georg; Weber, Jürgen; Disch, Christoph; Schuck, Elmar; Ittrich, Carina; Guth, Brian D

2015-01-01

Human induced pluripotent stem cell-derived cardiomyocytes are available from various sources and they are being evaluated for safety testing. Several platforms are available offering different assay principles and read-out parameters: patch-clamp and field potential recording, imaging or photometry, impedance measurement, and recording of contractile force. Routine use will establish which assay principle and which parameters best serve the intended purpose. We introduce a combination of field potential recording and calcium ratiometry from spontaneously beating cardiomyocytes as a novel assay providing a complementary read-out parameter set. Field potential recording is performed using a commercial multi-well multi-electrode array platform. Calcium ratiometry is performed using a fiber optic illumination and silicon avalanche photodetectors. Data condensation and statistical analysis are designed to enable statistical inference of differences and equivalence with regard to a solvent control. Simultaneous recording of field potentials and calcium transients from spontaneously beating monolayers was done in a nine-well format. Calcium channel blockers (e.g. nifedipine) and a blocker of calcium store release (ryanodine) can be recognized and discriminated based on the calcium transient signal. An agonist of L-type calcium channels, FPL 64176, increased and prolonged the calcium transient, whereas BAY K 8644, another L-type calcium channel agonist, had no effect. Both FPL 64176 and various calcium channel antagonists have chronotropic effects, which can be discriminated from typical "chronotropic" compounds, like (±)isoprenaline (positive) and arecaidine propargyl ester (negative), based on their effects on the calcium transient. Despite technical limitations in temporal resolution and exact matching of composite calcium transient with the field potential of a subset of cells, the combined recording platform enables a refined interpretation of the field potential recording and a more reliable identification of drug effects on calcium handling. Copyright © 2015 Elsevier Inc. All rights reserved.

Investigations of Au-198 as radiotracer in laboratory porous media using gamma camera: a preliminary study

NASA Astrophysics Data System (ADS)

Othman, N.; Kamal, W. H. B. Wan; Yusof, N. H.; Engku Chik, E. M. F.; Yunos, M. A. S.; Adnan, M. A. K.; Shari, M. R.

2018-01-01

Preliminary experiment has been carried out using irradiated Au-198 as radiotracer inside the laboratory porous media. The objectives are to check the compatibility of Au-198 as the radiotracer inside the porous media as well as to provide insights of fluid hydrodynamics inside the media using gamma camera.198Au is gamma emitter isotope with half-life of 2.7 days and energy of 0.41 MeV (99%). The porous media consists of fine sandstone with grain size 850μm, lubricant as the mimic of original oil in plant (OOIP) or trapped oil and a layer of cement on top of the rig as the bed rock. Gamma camera is arranged next to the porous media in order to capture the movement of radiotracer which has been set to 1minute per frame. Initially, the gold wire which has isotope of 197Au was irradiated inside the rotary rack of Reactor Triga PUSPATI (RTP) to produce 198Au. RTP is located in Nuclear Malaysia, Bangi has energy of 750kW and neutron flux of 5 × 102 n/cm2/s. 198Au, which is in liquid form, is injected inside the porous media and monitored and recorded by gamma camera. The gamma camera gives a quantitative determination of local fluid saturations over the area of observation.

Src homology 2-domain containing leukocyte-specific phosphoprotein of 76 kDa is mandatory for TCR-mediated inside-out signaling, but dispensable for CXCR4-mediated LFA-1 activation, adhesion, and migration of T cells.

PubMed

Horn, Jessica; Wang, Xiaoqian; Reichardt, Peter; Stradal, Theresia E; Warnecke, Nicole; Simeoni, Luca; Gunzer, Matthias; Yablonski, Deborah; Schraven, Burkhart; Kliche, Stefanie

2009-11-01

Engagement of the TCR or of chemokine receptors such as CXCR4 induces adhesion and migration of T cells via so-called inside-out signaling pathways. The molecular processes underlying inside-out signaling events are as yet not completely understood. In this study, we show that TCR- and CXCR4-mediated activation of integrins critically depends on the membrane recruitment of the adhesion- and degranulation-promoting adapter protein (ADAP)/Src kinase-associated phosphoprotein of 55 kDa (SKAP55)/Rap1-interacting adapter protein (RIAM)/Rap1 module. We further demonstrate that the Src homology 2 domain containing leukocyte-specific phosphoprotein of 76 kDa (SLP76) is crucial for TCR-mediated inside-out signaling and T cell/APC interaction. Besides facilitating membrane recruitment of ADAP, SKAP55, and RIAM, SLP76 regulates TCR-mediated inside-out signaling by controlling the activation of Rap1 as well as Rac-mediated actin polymerization. Surprisingly, however, SLP76 is not mandatory for CXCR4-mediated inside-out signaling. Indeed, both CXCR4-induced T cell adhesion and migration are not affected by loss of SLP76. Moreover, after CXCR4 stimulation, the ADAP/SKAP55/RIAM/Rap1 module is recruited to the plasma membrane independently of SLP76. Collectively, our data indicate a differential requirement for SLP76 in TCR- vs CXCR4-mediated inside-out signaling pathways regulating T cell adhesion and migration.

Three New Species of Shoot Fly, Atherigona spp., from Northern Thailand

PubMed Central

Moophayak, Kittikhun; Kurahashi, Hiromu; Sukontason, Kabkaew L.

2011-01-01

Three new species of shoot fly, Atherigona Rondani (subgenus Acritochaeta Grimshaw) (Diptera: Muscidae), are described from northern Thailand, based on morphological characteristics of males. Unique features of A. komi sp. n. include a distinct spiral groove on the dorsal aspect of the fore femur and two dark apical wing spots, whereas A. chiangmaiensis sp. n. is recognized by the presence of one large patch on the apical wing spot, appearing as a large and smaller wave-shaped patch, and no distinct pattern on tergites. A. thailandica sp. n. displays a remarkable dark boomerang-shaped patch along the wing margin and fore femur, with two rows of long hairs on the dorsal surface. Male terminalia are also different in the new species, showing distinctive characteristics. This paper also presents five newly recorded species in Thailand; Atherigona maculigera Stein, Atherigona ovatipennis vietnamensis Shinonaga et Thinh, Atherigona pallidipalpis Malloch, Atherigona seticauda Malloch, and Atherigona setitarsus Shinonaga et Thinh. A key is provided for the adult males of Atherigona recorded in Thailand, all belonging to the subgenus Acritochaeta, except for A. soccata Rondani. PMID:22233520

Old models explain new observations of butterfly movement at patch edges.

PubMed

Crone, Elizabeth E; Schultz, Cheryl B

2008-07-01

Understanding movement in heterogeneous environments is central to predicting how landscape changes affect animal populations. Several recent studies point out an intriguing and distinctive looping behavior by butterflies at habitat patch edges and hypothesize that this behavior requires a new framework for analyzing animal movement. We show that this looping behavior could be caused by a longstanding movement model, biased correlated random walk, with bias toward habitat patches. The ability of this longstanding model to explain recent observations reinforces the point that butterflies respond to habitat heterogeneity and do not move randomly through heterogeneous environments. We discuss the implications of different movement models for predicting butterfly responses to landscape change, and our rationale for retaining longstanding movement models, rather than developing new modeling frameworks for looping behavior at patch edges.

Organic Nitrogen-Driven Stimulation of Arbuscular Mycorrhizal Fungal Hyphae Correlates with Abundance of Ammonia Oxidizers

PubMed Central

Bukovská, Petra; Gryndler, Milan; Gryndlerová, Hana; Püschel, David; Jansa, Jan

2016-01-01

Large fraction of mineral nutrients in natural soil environments is recycled from complex and heterogeneously distributed organic sources. These sources are explored by both roots and associated mycorrhizal fungi. However, the mechanisms behind the responses of arbuscular mycorrhizal (AM) hyphal networks to soil organic patches of different qualities remain little understood. Therefore, we conducted a multiple-choice experiment examining hyphal responses to different soil patches within the root-free zone by two AM fungal species (Rhizophagus irregularis and Claroideoglomus claroideum) associated with Medicago truncatula, a legume forming nitrogen-fixing root nodules. Hyphal colonization of the patches was assessed microscopically and by quantitative real-time PCR (qPCR) using AM taxon-specific markers, and the prokaryotic and fungal communities in the patches (pooled per organic amendment treatment) were profiled by 454-amplicon sequencing. Specific qPCR markers were then designed and used to quantify the abundance of prokaryotic taxa showing the strongest correlation with the pattern of AM hyphal proliferation in the organic patches as per the 454-sequencing. The hyphal density of both AM fungi increased due to nitrogen (N)-containing organic amendments (i.e., chitin, DNA, albumin, and clover biomass), while no responses as compared to the non-amended soil patch were recorded for cellulose, phytate, or inorganic phosphate amendments. Abundances of several prokaryotes, including Nitrosospira sp. (an ammonium oxidizer) and an unknown prokaryote with affiliation to Acanthamoeba endosymbiont, which were frequently recorded in the 454-sequencing profiles, correlated positively with the hyphal responses of R. irregularis to the soil amendments. Strong correlation between abundance of these two prokaryotes and the hyphal responses to organic soil amendments by both AM fungi was then confirmed by qPCR analyses using all individual replicate patch samples. Further research is warranted to ascertain the causality of these correlations and particularly which direct roles (if any) do these prokaryotes play in the observed AM hyphal responses to organic N amendment, organic N utilization by the AM fungus and its (N-unlimited) host plant. Further, possible trophic dependencies between the different players in the AM hyphosphere needs to be elucidated upon decomposing the organic N sources. PMID:27242732

Organic Nitrogen-Driven Stimulation of Arbuscular Mycorrhizal Fungal Hyphae Correlates with Abundance of Ammonia Oxidizers.

PubMed

Bukovská, Petra; Gryndler, Milan; Gryndlerová, Hana; Püschel, David; Jansa, Jan

2016-01-01

Large fraction of mineral nutrients in natural soil environments is recycled from complex and heterogeneously distributed organic sources. These sources are explored by both roots and associated mycorrhizal fungi. However, the mechanisms behind the responses of arbuscular mycorrhizal (AM) hyphal networks to soil organic patches of different qualities remain little understood. Therefore, we conducted a multiple-choice experiment examining hyphal responses to different soil patches within the root-free zone by two AM fungal species (Rhizophagus irregularis and Claroideoglomus claroideum) associated with Medicago truncatula, a legume forming nitrogen-fixing root nodules. Hyphal colonization of the patches was assessed microscopically and by quantitative real-time PCR (qPCR) using AM taxon-specific markers, and the prokaryotic and fungal communities in the patches (pooled per organic amendment treatment) were profiled by 454-amplicon sequencing. Specific qPCR markers were then designed and used to quantify the abundance of prokaryotic taxa showing the strongest correlation with the pattern of AM hyphal proliferation in the organic patches as per the 454-sequencing. The hyphal density of both AM fungi increased due to nitrogen (N)-containing organic amendments (i.e., chitin, DNA, albumin, and clover biomass), while no responses as compared to the non-amended soil patch were recorded for cellulose, phytate, or inorganic phosphate amendments. Abundances of several prokaryotes, including Nitrosospira sp. (an ammonium oxidizer) and an unknown prokaryote with affiliation to Acanthamoeba endosymbiont, which were frequently recorded in the 454-sequencing profiles, correlated positively with the hyphal responses of R. irregularis to the soil amendments. Strong correlation between abundance of these two prokaryotes and the hyphal responses to organic soil amendments by both AM fungi was then confirmed by qPCR analyses using all individual replicate patch samples. Further research is warranted to ascertain the causality of these correlations and particularly which direct roles (if any) do these prokaryotes play in the observed AM hyphal responses to organic N amendment, organic N utilization by the AM fungus and its (N-unlimited) host plant. Further, possible trophic dependencies between the different players in the AM hyphosphere needs to be elucidated upon decomposing the organic N sources.

Localized Patch Clamping of Plasma Membrane of a Polarized Plant Cell 1

PubMed Central

Taylor, Alison R.; Brownlee, Colin

1992-01-01

We used an ultraviolet laser to rupture a small region of cell wall of a polarized Fucus spiralis rhizoid cell and gained localized access to the plasma membrane at the growing apex. Careful control of cell turgor enabled a small portion of plasma membrane-bound cytoplasm to be exposed. Gigaohm seals allowing single-channel recordings were obtained with a high success rate using this method with conventional patch clamp techniques. ImagesFigure 1 PMID:16669092

The human red cell voltage-regulated cation channel. The interplay with the chloride conductance, the Ca(2+)-activated K(+) channel and the Ca(2+) pump.

PubMed

Bennekou, P; Kristensen, B I; Christophersen, P

2003-09-01

The activation/deactivation kinetics of the human erythrocyte voltage-dependent cation channel was characterized at the single-channel level using inside-out patches. It was found that the time dependence for voltage activation after steps to positive membrane potentials was slow ( t(1/2) about 30 s), whereas the deactivation was fast ( t(1/2) about 15 ms). Both activation and deactivation of this channel were also demonstrated in intact red cells in suspension. At very positive membrane potentials generated by suspension in extracellular low Cl(-) concentrations, the cation conductance switched on with a time constant of about 2 min. Deactivation of the cation channel was clearly demonstrated during transient activation of the Gárdos channel elicited by Ca(2+) influx via the cation channel and ensuing efflux via the Ca(2+) pump. Thus, the voltage-dependent cation channel, the Gárdos channel and the Ca(2+) pump constitute a coupled feedback-regulated system that may become operative under physiological conditions.

Modulation of the olfactory CNG channel by Ptdlns(3,4,5)P3.

PubMed

Zhainazarov, A B; Spehr, M; Wetzel, C H; Hatt, H; Ache, B W

2004-09-01

Recent data suggest that the 3-phosphoinositides can modulate cyclic nucleotide signaling in rat olfactory receptor neurons (ORNs). Given the ability of diverse lipids to modulate ion channels, we asked whether phosphatidylinositol 3,4,5-trisphosphate (PIP3) can regulate the olfactory cyclic nucleotide-gated (CNG) channel as a possible mechanism for this modulation. We show that applying PIP3 to the intracellular side of inside-out patches from rat ORNs inhibits activation of the olfactory CNG channel by cAMP. The effect of PIP3 is immediate and partially reversible, and reflects an increase in the EC50 of cAMP, not a reduction in the single-channel current amplitude. The effect of PIP3 is significantly stronger than that of PIP2; other phospholipids tested have no appreciable effect on channel activity. PIP3 similarly inhibits the recombinant heteromeric (A2/A4) and homomeric (A2) olfactory CNG channel expressed in HEK293 cells, suggesting that PIP3 acts directly on the channel. These findings indicate that 3-phosphoinositides can be functionally important regulators of CNG channels.

A miniaturized planar patch-clamp system for transportable use.

PubMed

Boussaoud, Adrien; Fonteille, Isabelle; Collier, Guilhem; Kermarrec, Frédérique; Vermont, Fabien; Tresallet, Eric; De Waard, Michel; Arnoult, Christophe; Picollet-D'hahan, Nathalie

2012-02-15

In the last decade, planar patch-clamp (PPC) has emerged as an innovative technology allowing parallel recordings of cellular electrophysiological activity on planar substrates. If PPC is widely adopted by the pharmaceutical sector, it remains poorly extended to other areas (i.e. environment and safety organizations) probably because of the large, expensive and non-easily transportable format of those commercial equipments. The present work describes for the first time a new compact and transportable planar patch-clamp system (named Toxint'patch or TIP, for Toxin detection with integrated patch-clamp) focusing on environmental matters and meant to be used in coastal laboratories, for direct on-site monitoring of the seawater and shellfish quality. The TIP system incorporates silicon chips tailored to monitor cellular ionic currents from cultured cells stably expressing a phycotoxin molecular target. The functionality of this novel briefcase-sized PPC system is described in terms of fluidic control, electronic performances with amplifying and filtering boards and of user interface for data acquisition and control implemented on a computer. Copyright © 2011 Elsevier B.V. All rights reserved.

Analysis of the hologram recording on the novel chloride photo-thermo-refractive glass

NASA Astrophysics Data System (ADS)

Ivanov, S. A.; Nikonorov, N. V.; Dubrovin, V. D.; Krykova, V. A.

2017-05-01

In this research, we present new holographic material based on fluoride photo-thermo-refractive glass(PTR) - chloride PTR glass. One of the benefit of this type of PTR glass is positive refractive index change. During this work, for the first-time volume Bragg gratings were recorded in this kind of material. The first experiments revealed that such gratings are mixed i.e. possess both absorption and phase components. Complex analysis shows that both refractive index and absorption coefficient are modulated inside the grating structure. We found out that at first there is no strict dependence of the refractive index change from dosage, but as we continue the process of thermal treatment - dependence is appear. Exposure influence on the refractive index change for this glass differs from fluoride one and shows some sort of saturation after the exposure of 4-6 J/cm2 . We distinguished refractive index change and absorption coefficient change and observed both behavior with increasing thermal treatment time. We found out that the increase of thermal treatment time results in the significant refractive index change. At the same time the absorption does `not practically change. It was found that maximum modulation of refractive index is comparable with fluoride PTR glass and achieves value of 1600 ppm. The modulation of absorption is equal to induced absorption caused by silver nanoparticles and depends from reading wavelength. Our study shows that almost all absorption is modulated inside the grating.

Microbial communities in sediment from Zostera marina patches, but not the Z. marina leaf or root microbiomes, vary in relation to distance from patch edge

PubMed Central

Ettinger, Cassandra L.; Voerman, Sofie E.; Lang, Jenna M.; Stachowicz, John J.

2017-01-01

Background Zostera marina (also known as eelgrass) is a foundation species in coastal and marine ecosystems worldwide and is a model for studies of seagrasses (a paraphyletic group in the order Alismatales) that include all the known fully submerged marine angiosperms. In recent years, there has been a growing appreciation of the potential importance of the microbial communities (i.e., microbiomes) associated with various plant species. Here we report a study of variation in Z. marina microbiomes from a field site in Bodega Bay, CA. Methods We characterized and then compared the microbial communities of root, leaf and sediment samples (using 16S ribosomal RNA gene PCR and sequencing) and associated environmental parameters from the inside, edge and outside of a single subtidal Z. marina patch. Multiple comparative approaches were used to examine associations between microbiome features (e.g., diversity, taxonomic composition) and environmental parameters and to compare sample types and sites. Results Microbial communities differed significantly between sample types (root, leaf and sediment) and in sediments from different sites (inside, edge, outside). Carbon:Nitrogen ratio and eelgrass density were both significantly correlated to sediment community composition. Enrichment of certain taxonomic groups in each sample type was detected and analyzed in regard to possible functional implications (especially regarding sulfur metabolism). Discussion Our results are mostly consistent with prior work on seagrass associated microbiomes with a few differences and additional findings. From a functional point of view, the most significant finding is that many of the taxa that differ significantly between sample types and sites are closely related to ones commonly associated with various aspects of sulfur and nitrogen metabolism. Though not a traditional model organism, we believe that Z. marina can become a model for studies of marine plant-microbiome interactions. PMID:28462046

Simultaneous recording of electrical activity and the underlying ionic currents in NG108-15 cells cultured on gold substrate.

PubMed

Acosta-García, Ma Cristina; Morales-Reyes, Israel; Jiménez-Anguiano, Anabel; Batina, Nikola; Castellanos, N P; Godínez-Fernández, R

2018-02-01

This paper shows the simultaneous recording of electrical activity and the underlying ionic currents by using a gold substrate to culture NG108-15 cells. Cells grown on two different substrates (plastic Petri dishes and gold substrates) were characterized quantitatively through scanning electron microscopy (SEM) as well as qualitatively by optical and atomic force microscopy (AFM). No significant differences were observed between the surface area of cells cultured on gold substrates and Petri dishes, as indicated by measurements performed on SEM images. We also evaluated the electrophysiological compatibility of the cells through standard patch-clamp experiments by analyzing features such as the resting potential, membrane resistance, ionic currents, etc. Cells grown on both substrates showed no significant differences in their dependency on voltage, as well as in the magnitude of the Na+ and K+ current density; however, cells cultured on the gold substrate showed a lower membrane capacitance when compared to those grown on Petri dishes. By using two separate patch-clamp amplifiers, we were able to record the membrane current with the conventional patch-clamp technique and through the gold substrate simultaneously. Furthermore, the proposed technique allowed us to obtain simultaneous recordings of the electrical activity (such as action potentials firing) and the underlying membrane ionic currents. The excellent conductivity of gold makes it possible to overcome important difficulties found in conventional electrophysiological experiments such as those presented by the resistance of the electrolytic bath solution. We conclude that the technique here presented constitutes a solution to the problem of the simultaneous recording of electrical activity and the underlying ionic currents, which for decades, had been solved only partially.

The effect of altitude, patch size and disturbance on species richness and density of lianas in montane forest patches

NASA Astrophysics Data System (ADS)

Mohandass, Dharmalingam; Campbell, Mason J.; Hughes, Alice C.; Mammides, Christos; Davidar, Priya

2017-08-01

The species richness and density of lianas (woody vines) in tropical forests is determined by various abiotic and biotic factors. Factors such as altitude, forest patch size and the degree of forest disturbance are known to exert strong influences on liana species richness and density. We investigated how liana species richness and density were concurrently influenced by altitude (1700-2360 m), forest patch size, forest patch location (edge or interior) and disturbance intensity in the tropical montane evergreen forests, of the Nilgiri and Palni hills, Western Ghats, southern India. All woody lianas (≥1 cm dbh) were enumerated in plots of 30 × 30 m in small, medium and large forest patches, which were located along an altitudinal gradient ranging from 1700 to 2360 m. A total of 1980 individual lianas were recorded, belonging to 45 species, 32 genera and 21 families, from a total sampling area of 13.86 ha (across 154 plots). Liana species richness and density decreased significantly with increasing altitude and increased with increasing forest patch size. Within forest patches, the proportion of forest edge or interior habitat influenced liana distribution and succession especially when compared across the patch size categories. Liana species richness and density also varied along the altitudinal gradient when examined using eco-physiological guilds (i.e. shade tolerance, dispersal mode and climbing mechanism). The species richness and density of lianas within these ecological guilds responded negatively to increasing altitude and positively to increasing patch size and additionally displayed differing sensitivities to forest disturbance. Importantly, the degree of forest disturbance significantly altered the relationship between liana species richness and density to increasing altitude and patches size, and as such is likely the primary influence on liana response to montane forest succession. Our findings suggest that managing forest disturbance in the examined montane forests would assist in conserving local liana diversity across the examined altitudinal range.

The Pixel Paradox and Transition-Metal Spectroscopy: One of Many Uses of the Handheld Digital Microscope in Chemical Demonstrations

ERIC Educational Resources Information Center

Vitz, Ed

2010-01-01

A handheld digital microscope (HDM) interfaced to a computer with a presentation projector is used to project an out-of-focus yellow patch on the screen, then the patch is brought into focus to show that, paradoxically, there are red and green but no yellow pixels. Chromaticity diagrams are used to discuss this observation and spectroscopic…

Slash disposal burns in pine patch-cuttings...a dialogue

Treesearch

Dale O. Hall

1967-01-01

Since 1963, there have been 17 slash disposal burns carried out successfully in pine patch-cuttings on the Challenge Experimental Forest, Yuba County, California. The burned units ranged from 2 to 46 acres. Costs per acre ranged from $8.42 to $60.97. Answers to questions most asked by foresters about broadcast burning pine slash are given in the form of a dialogue....

Vice President Mike Pence Visits Kennedy Space Center

NASA Image and Video Library

2017-07-06

Kennedy Space Center Bob Cabana, left, and NASA's Acting Administrator Robert Lightfoot, right present Vice President Mike Pence with a framed plaque. On the back of the plaque are patches from each of Cabana's four space shuttle mission, STS-88, STS-53, STS-65, STS-41, and an inscription thanking the Vice President for his support of NASA. During his visit to Kennedy, the Vice President spoke inside the iconic Vehicle Assembly Building, where he thanked employees for advancing American leadership in space.

Phenomenological Studies of the Response of Granular and Geological Media to High-Speed (Mach 1-5) Projectiles

DTIC Science & Technology

2011-10-06

applied, the microcapsules are broken and the color-forming material reacts with the color-developing material. Red patches appear on the film and the...used inorganic silicate-sealing agent and succeeded to l:i"eeze the trajectory of sphere’s motion. Penetration velocity inside sand layer was...with aqueous colored inks. After firing. test chamber was retri eved and the whole specimens was dipped into a s ilicone-based inorganic po lymer

HTS techniques for patch clamp-based ion channel screening - advances and economy.

PubMed

Farre, Cecilia; Fertig, Niels

2012-06-01

Ten years ago, the first publication appeared showing patch clamp recordings performed on a planar glass chip instead of using a conventional patch clamp pipette. "Going planar" proved to revolutionize ion channel drug screening as we know it, by allowing high quality measurements of ion channels and their effectors at a higher throughput and at the same time de-skilling the highly laborious technique. Over the years, platforms evolved in response to user requirements regarding experimental features, data handling plus storage, and suitable target diversity. This article gives a snapshot image of patch clamp-based ion channel screening with focus on platforms developed to meet requirements of high-throughput screening environments. The commercially available platforms are described, along with their benefits and drawbacks in ion channel drug screening. Automated patch clamp (APC) platforms allow faster investigation of a larger number of ion channel active compounds or cell clones than previously possible. Since patch clamp is the only method allowing direct, real-time measurements of ion channel activity, APC holds the promise of picking up high quality leads, where they otherwise would have been overseen using indirect methods. In addition, drug candidate safety profiling can be performed earlier in the drug discovery process, avoiding late-phase compound withdrawal due to safety liability issues, which is highly costly and inefficient.

Hot section viewing system

NASA Technical Reports Server (NTRS)

Morey, W. W.

1984-01-01

This report covers the development and testing of a prototype combustor viewing system. The system allows one to see and record images from the inside of an operating gas turbine combustor. The program proceeded through planned phases of conceptual design, preliminary testing to resolve problem areas, prototype design and fabrication, and rig testing. Successful tests were completed with the viewing system in the laboratory, in a high pressure combustor rig, and on a Pratt and Whitney PW20307 jet engine. Both film and video recordings were made during the tests. Digital image analysis techniques were used to enhance images and bring out special effects. The use of pulsed laser illumination was also demonstrated as a means for observing liner surfaces in the presence of luminous flame.

Systems Issues Pertaining to Holographic Optical Data Storage in Thick Bacteriorhodopsin Films

NASA Technical Reports Server (NTRS)

Downie, John D.; Timucin, Dogan A.; Gary, Charles K.; Oezcan, Meric; Smithey, Daniel T.; Crew, Marshall; Lau, Sonie (Technical Monitor)

1998-01-01

The optical data storage capacity and raw bit-error-rate achievable with thick photochromic bacteriorhodopsin (BR) films are investigated for sequential recording and read- out of angularly- and shift-multiplexed digital holograms inside a thick blue-membrane D85N BR film. We address the determination of an exposure schedule that produces equal diffraction efficiencies among each of the multiplexed holograms. This exposure schedule is determined by numerical simulations of the holographic recording process within the BR material, and maximizes the total grating strength. We also experimentally measure the shift selectivity and compare the results to theoretical predictions. Finally, we evaluate the bit-error-rate of a single hologram, and of multiple holograms stored within the film.

Inhibition of the KCa3.1 channels by AMP-activated protein kinase in human airway epithelial cells

PubMed Central

Klein, Hélène; Garneau, Line; Trinh, Nguyen Thu Ngan; Privé, Anik; Dionne, François; Goupil, Eugénie; Thuringer, Dominique; Parent, Lucie; Brochiero, Emmanuelle; Sauvé, Rémy

2009-01-01

The vectorial transport of ions and water across epithelial cells depends to a large extent on the coordination of the apical and basolateral ion fluxes with energy supply. In this work we provide the first evidence for a regulation by the 5′-AMP-activated protein kinase (AMPK) of the calcium-activated potassium channel KCa3.1 expressed at the basolateral membrane of a large variety of epithelial cells. Inside-out patch-clamp experiments performed on human embryonic kidney (HEK) cells stably transfected with KCa3.1 first revealed a decrease in KCa3.1 activity following the internal addition of AMP at a fixed ATP concentration. This effect was dose dependent with half inhibition at 140 μM AMP in 1 mM ATP. Evidence for an interaction between the COOH-terminal region of KCa3.1 and the γ1-subunit of AMPK was next obtained by two-hybrid screening and pull-down experiments. Our two-hybrid analysis confirmed in addition that the amino acids extending from Asp380 to Ala400 in COOH-terminal were essential for the interaction AMPK-γ1/KCa3.1. Inside-out experiments on cells coexpressing KCa3.1 with the dominant negative AMPK-γ1-R299G mutant showed a reduced sensitivity of KCa3.1 to AMP, arguing for a functional link between KCa3.1 and the γ1-subunit of AMPK. More importantly, coimmunoprecipitation experiments carried out on bronchial epithelial NuLi cells provided direct evidence for the formation of a KCa3.1/AMPK-γ1 complex at endogenous AMPK and KCa3.1 expression levels. Finally, treating NuLi monolayers with the membrane permeant AMPK activator 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) caused a significant decrease of the KCa3.1-mediated short-circuit currents, an effect reversible by coincubation with the AMPK inhibitor Compound C. These observations argue for a regulation of KCa3.1 by AMPK in a functional epithelium through protein/protein interactions involving the γ1-subunit of AMPK. PMID:19052260

Analysis of earthquake clustering and source spectra in the Salton Sea Geothermal Field

NASA Astrophysics Data System (ADS)

Cheng, Y.; Chen, X.

2015-12-01

The Salton Sea Geothermal field is located within the tectonic step-over between San Andreas Fault and Imperial Fault. Since the 1980s, geothermal energy exploration has resulted with step-like increase of microearthquake activities, which mirror the expansion of geothermal field. Distinguishing naturally occurred and induced seismicity, and their corresponding characteristics (e.g., energy release) is important for hazard assessment. Between 2008 and 2014, seismic data recorded by a local borehole array were provided public access from CalEnergy through SCEC data center; and the high quality local recording of over 7000 microearthquakes provides unique opportunity to sort out characteristics of induced versus natural activities. We obtain high-resolution earthquake location using improved S-wave picks, waveform cross-correlation and a new 3D velocity model. We then develop method to identify spatial-temporally isolated earthquake clusters. These clusters are classified into aftershock-type, swarm-type, and mixed-type (aftershock-like, with low skew, low magnitude and shorter duration), based on the relative timing of largest earthquakes and moment-release. The mixed-type clusters are mostly located at 3 - 4 km depth near injection well; while aftershock-type clusters and swarm-type clusters also occur further from injection well. By counting number of aftershocks within 1day following mainshock in each cluster, we find that the mixed-type clusters have much higher aftershock productivity compared with other types and historic M4 earthquakes. We analyze detailed spatial variation of 'b-value'. We find that the mixed-type clusters are mostly located within high b-value patches, while large (M>3) earthquakes and other types of clusters are located within low b-value patches. We are currently processing P and S-wave spectra to analyze the spatial-temporal correlation of earthquake stress parameter and seismicity characteristics. Preliminary results suggest that the mixed-type clusters and high b-value patches are spatially correlated with low stress drop earthquakes, indicating high-productivity microearthquakes within low differential stress region, potentially due to deeper injection activities.

The influence of tyre contact patch and on the stopping distance of automotive vehicles

NASA Astrophysics Data System (ADS)

Selig, M.; Ball, A.; Ash, J.; Schmidt, K.

2012-05-01

This contribution presents the experimental tests results about the influence of the tyre contact patch on the stopping distance of automotive vehicles. The objective of the performed tests is the evaluation of the effect of tyre inflation pressure, hence the resulting tyre contact patch on the braking system and the brake distance. The conditions of the experiment are a dry and level road surface without steering inputs. To record scientific results, a brake robot system is used. The benefit of a robotic system is the elimination of the interfering variable driver, who is not able to apply the brake system at the same time with the same force. State-of-the-art data acquisition tools are used to log the data.

Vision inspection system and method

NASA Technical Reports Server (NTRS)

Huber, Edward D. (Inventor); Williams, Rick A. (Inventor)

1997-01-01

An optical vision inspection system (4) and method for multiplexed illuminating, viewing, analyzing and recording a range of characteristically different kinds of defects, depressions, and ridges in a selected material surface (7) with first and second alternating optical subsystems (20, 21) illuminating and sensing successive frames of the same material surface patch. To detect the different kinds of surface features including abrupt as well as gradual surface variations, correspondingly different kinds of lighting are applied in time-multiplexed fashion to the common surface area patches under observation.

Analysis of thermal radiation in coal-fired furnaces

NASA Astrophysics Data System (ADS)

Miles, Jonathan J.; Hammaker, Robert G.; Madding, Robert P.; Sunderland, J. E.

1997-04-01

Many utilities throughout the United States have added infrared scanning to their arsenal of techniques for inspection and predictive maintenance programs. Commercial infrared scanners are not designed, however, to withstand the searing interiors of boilers, which can exceed 2500 degrees Fahrenheit. Two high-temperature lenses designed to withstand the hostile environment inside a boiler for extended periods of time were developed by the EPRI M&D Center, thus permitting real-time measurement of steam tube temperatures and subsequent analysis of tube condition, inspection of burners, and identification of hot spots. A study was conducted by Sunderland Engineering, Inc. and EPRI M&D in order to characterize the radiative interactions that affect infrared measurements made inside a commercial, coal- fired, water-tube boiler. A comprehensive literature search exploring the existing record of results pertaining to analytical and experimental determination of radiative properties of coal-combustion byproducts was performed. An experimental component intended to provide data for characterization of the optical properties of hot combustion byproducts inside a coal-fired furnace was carried out. The results of the study indicate that hot gases, carbon particles, and fly ash, which together compose the medium inside a boiler, affect to varying degrees the transport of infrared radiation across a furnace. Techniques for improved infrared measurement across a coal-fired furnace are under development.

Contrasts between whole-plant and local nutrient levels determine root growth and death in Ailanthus altissima (Simaroubaceae).

PubMed

Hu, Fengqin; Mou, Paul P; Weiner, Jacob; Li, Shuo

2014-05-01

• There is an ongoing debate about the importance of whole-plant control vs. local modular mechanisms for root growth. We conducted a split-root experiment with different patch/background levels of nitrogen to examine whether local root growth and death are controlled by local resource levels or at the whole-plant level.• Three microrhizotrons with 0, 10, and 100 µg N/g growth medium levels (74 g growth medium each) were attached to pots of high or low soil N in which one Ailanthus altissima individual was growing. One fine root was guided into each of the microrhizotrons and photographed every 4 d. Plants were harvested after 28 d; root growth and mortality in the microrhizotrons were recorded. Changes in root length, number of laterals, and interlateral length were determined from the photos and analyzed.• While overall plant growth was influenced by background N level, both patch and background N levels influenced root growth and mortality in patches. Local roots proliferated most when the patch N level was high and background level low, and they proliferated least and showed highest mortality when patch N was low and the background level high.• The fate of roots growing in a patch is influenced by the resource environment of the plant's other roots as well as the resource levels in the patch itself. Thus, the growth and death of roots in patches is determined by both modular and whole-plant mechanisms. © 2014 Botanical Society of America, Inc.

Electrophysiological Recordings from Lobula Plate Tangential Cells in Drosophila.

PubMed

Mauss, Alex S; Borst, Alexander

2016-01-01

Drosophila has emerged as an important model organism for the study of the neural basis of behavior. Its main asset is the experimental accessibility of identified neurons by genetic manipulation and physiological recordings. Drosophila therefore offers the opportunity to reach an integrative understanding of the development and neural underpinnings of behavior at all processing stages, from sensing to motor control, in a single species. Here, we will provide an account of the procedures involved in recording the electrical potential of individual neurons in the visual system of adult Drosophila using the whole-cell patch-clamp method. To this end, animals are fixed to a holder and mounted below a recording chamber. The head capsule is cut open and the glial sheath covering the brain is ruptured by a combination of shearing and enzymatic digest. Neuronal somata are thus exposed and targeted by low-resistance patch electrodes. After formation of a high resistance seal, electrical access to the cell is gained by small current pulses and suction. Stable recordings of large neurons are feasible for >1 h and can be combined with controlled visual stimulation as well as genetic and pharmacological manipulation of upstream circuit elements to infer circuit function in great detail.

Instrument for Analysis of Greenland's Glacier Mills

NASA Technical Reports Server (NTRS)

Behar, Alberto E.; Matthews, Jaret B.; Tran, Hung B.; Steffen, Konrad; McGrath, Dan; Phillips, Thomas; Elliot, Andrew; OHern, Sean; Lutz, Colin; Martin, Sujita;

Increase in cytosolic Ca2+ produced by hypoxia and other depolarizing stimuli activates a non-selective cation channel in chemoreceptor cells of rat carotid body

PubMed Central

Kang, Dawon; Wang, Jiaju; Hogan, James O; Vennekens, Rudi; Freichel, Marc; White, Carl; Kim, Donghee

2014-01-01

The current model of O2 sensing by carotid body chemoreceptor (glomus) cells is that hypoxia inhibits the outward K+ current and causes cell depolarization, Ca2+ influx via voltage-dependent Ca2+ channels and a rise in intracellular [Ca2+] ([Ca2+]i). Here we show that hypoxia (<5% O2), in addition to inhibiting the two-pore domain K+ channels TASK-1/3 (TASK), indirectly activates an ∼20 pS channel in isolated glomus cells. The 20 pS channel was permeable to K+, Na+ and Cs+ but not to Cl− or Ca2+. The 20 pS channel was not sensitive to voltage. Inhibition of TASK by external acid, depolarization of glomus cells with high external KCl (20 mm) or opening of the Ca2+ channel with FPL64176 activated the 20 pS channel when 1 mm Ca2+ was present in the external solution. Ca2+ (10 μm) applied to the cytosolic side of inside-out patches activated the 20 pS channel. The threshold [Ca2+]i for activation of the 20 pS channel in cell-attached patches was ∼200 nm. The reversal potential of the 20 pS channel was estimated to be −28 mV. Our results reveal a sequential mechanism in which hypoxia (<5% O2) first inhibits the K+ conductance and then activates a Na+-permeable, non-selective cation channel via depolarization-induced rise in [Ca2+]i. Our results suggest that inhibition of K+ efflux and stimulation of Na+ influx both contribute to the depolarization of glomus cells during moderate to severe hypoxia. PMID:24591572

Phenformin has a direct inhibitory effect on the ATP-sensitive potassium channel.

PubMed

Aziz, Qadeer; Thomas, Alison; Khambra, Tapsi; Tinker, Andrew

2010-05-25

The biguanides, phenformin and metformin, are used in the treatment of type II diabetes mellitus, as well as being routinely used in studies investigating AMPK activity. We used the patch-clamp technique and rubidium flux assays to determine the role of these drugs in ATP-sensitive K+ channel (K(ATP)) regulation in cell lines expressing the cloned components of K(ATP) and the current natively expressed in vascular smooth muscle cells (VSMCs). Phenformin but not metformin inhibits a number of variants of K(ATP) including the cloned equivalents of currents present in vascular and non-vascular smooth muscle (Kir6.1/SUR2B and Kir6.2/SUR2B) and pancreatic beta-cells (Kir6.2/SUR1). However it does not inhibit the current potentially present in cardiac myocytes (Kir6.2/SUR2A). The highest affinity interaction is seen with Kir6.1/SUR2B (IC50=0.55 mM) and it also inhibits the current in native vascular smooth muscle cells. The extent and rate of inhibition are similar to that seen with the known K(ATP) blocker PNU 37883A. Additionally, phenformin inhibited the current elicited through the Kir6.2DeltaC26 (functional without SUR) channel with an IC50 of 1.78 mM. Phenformin reduced the open probability of Kir6.1/SUR2B channels by approximately 90% in inside-out patches. These findings suggest that phenformin interacts directly with the pore-forming Kir6.0 subunit however the sulphonylurea receptor is able to significantly modulate the affinity. It is likely to block from the intracellular side of the channel in a manner analogous to that of PNU 37883A. Copyright 2010 Elsevier B.V. All rights reserved.

Mechanosensitive cation channels in human leukaemia cells: calcium permeation and blocking effect

PubMed Central

Staruschenko, Alexandr V; Vedernikova, Elena A

2002-01-01

Cell-attached and inside-out patch-clamp methods were employed to identify and characterize mechanosensitive (MS) ionic channels in the plasma membrane of human myeloid leukaemia K562 cells. A reversible activation of gadolinium-blockable mechanogated currents in response to negative pressure application was found in 58 % of stable patches (n = 317). I-V relationships measured with a sodium-containing pipette solution showed slight inward rectification. Data analysis revealed the presence of two different populations of channels that were distinguishable by their conductance properties (17.2 ± 0.3 pS and 24.5 ± 0.5 pS), but were indistinguishable with regard to their selective and pharmacological properties. Ion-substitution experiments indicated that MS channels in leukaemia cells were permeable to cations but not to anions and do not discriminate between Na+ and K+. The channels were fully impermeable to large organic cations such as Tris+ and N-methyl-d-glucamine ions (NMDG+). Ca2+ permeation and blockade of MS channels were examined using pipettes containing different concentrations of Ca2+. In the presence of 2 mm CaCl2, when other cations were impermeant, both outward and inward single-channel currents were observed; the I-V relationship showed a unitary conductance of 7.7 ± 1.0 pS. The relative permeability value, PCa/PK, was equal to 0.75, as estimated at physiological Ca2+ concentrations. Partial or full inhibition of inward Ca2+ currents through MS channels was observed at higher concentrations of external Ca2+ (10 or 20 mm). No MS channels were activated when using a pipette containing 90 mm CaCl2. Monovalent mechanogated currents were not significantly affected by extracellular Ca2+ at concentrations within the physiological range (0-2 mm), and at some higher Ca2+ concentrations. PMID:12015421

Amiodarone inhibits sarcolemmal but not mitochondrial KATP channels in Guinea pig ventricular cells.

PubMed

Sato, Toshiaki; Takizawa, Taichi; Saito, Tomoaki; Kobayashi, Satoru; Hara, Yukio; Nakaya, Haruaki

2003-12-01

ATP-sensitive K(+) (KATP) channels are present on the sarcolemma (sarcKATP channels) and mitochondria (mitoKATP channels) of cardiac myocytes. Amiodarone, a class III antiarrhythmic drug, reduces sudden cardiac death in patients with organic heart disease. The objective of the present study was to investigate the effects of amiodarone on sarcKATP and mitoKATP channels. Single sarcKATP channel current and flavoprotein fluorescence were measured in guinea pig ventricular myocytes to assay sarcKATP and mitoKATP channel activity, respectively. Amiodarone inhibited the sarcKATP channel currents in a concentration-dependent manner without affecting its unitary amplitude. The IC50 values were 0.35 microM in the inside-out patch exposed to an ATP-free solution and 2.8 microM in the cell-attached patch under metabolic inhibition, respectively. Amiodarone (10 microM) alone did not oxidize the flavoprotein. In addition, the oxidative effect of the mitoKATP channel opener diazoxide (100 microM) was unaffected by amiodarone. Exposure to ouabain (1 mM) for 30 min produced mitochondrial Ca(2+) overload, and the intensity of rhod-2 fluorescence increased to 246 +/- 16% of baseline (n = 9). Amiodarone did not alter the ouabain-induced mitochondrial Ca(2+) overload (236 +/- 10% of baseline, n = 7). Treatment with diazoxide significantly reduced the ouabain-induced mitochondrial Ca(2+) overload (158 +/- 15% of baseline, n = 8, p < 0.05 versus ouabain); this effect was not abolished by amiodarone (154 +/- 10% of baseline, n = 8, p < 0.05 versus ouabain). These results suggest that amiodarone inhibits sarcKATP but not mitoKATP channels in cardiac myocytes. Such an action of amiodarone may effectively prevent ischemic arrhythmias without causing ischemic damage.

Capsule Endoscopy

MedlinePlus

... attached to your abdomen. Each patch contains an antenna with wires that connect to a recorder. Some ... your waist. The camera sends images to an antenna on your abdomen, which feeds the data to ...

An experimental test of the habitat-amount hypothesis for saproxylic beetles in a forested region.

PubMed

Seibold, Sebastian; Bässler, Claus; Brandl, Roland; Fahrig, Lenore; Förster, Bernhard; Heurich, Marco; Hothorn, Torsten; Scheipl, Fabian; Thorn, Simon; Müller, Jörg

2017-06-01

The habitat-amount hypothesis challenges traditional concepts that explain species richness within habitats, such as the habitat-patch hypothesis, where species number is a function of patch size and patch isolation. It posits that effects of patch size and patch isolation are driven by effects of sample area, and thus that the number of species at a site is basically a function of the total habitat amount surrounding this site. We tested the habitat-amount hypothesis for saproxylic beetles and their habitat of dead wood by using an experiment comprising 190 plots with manipulated patch sizes situated in a forested region with a high variation in habitat amount (i.e., density of dead trees in the surrounding landscape). Although dead wood is a spatio-temporally dynamic habitat, saproxylic insects have life cycles shorter than the time needed for habitat turnover and they closely track their resource. Patch size was manipulated by adding various amounts of downed dead wood to the plots (~800 m³ in total); dead trees in the surrounding landscape (~240 km 2 ) were identified using airborne laser scanning (light detection and ranging). Over 3 yr, 477 saproxylic species (101,416 individuals) were recorded. Considering 20-1,000 m radii around the patches, local landscapes were identified as having a radius of 40-120 m. Both patch size and habitat amount in the local landscapes independently affected species numbers without a significant interaction effect, hence refuting the island effect. Species accumulation curves relative to cumulative patch size were not consistent with either the habitat-patch hypothesis or the habitat-amount hypothesis: several small dead-wood patches held more species than a single large patch with an amount of dead wood equal to the sum of that of the small patches. Our results indicate that conservation of saproxylic beetles in forested regions should primarily focus on increasing the overall amount of dead wood without considering its spatial arrangement. This means dead wood should be added wherever possible including in local landscapes with low or high dead-wood amounts. For species that have disappeared from most forests owing to anthropogenic habitat degradation, this should, however, be complemented by specific conservation measures pursued within their extant distributional ranges. © 2017 by the Ecological Society of America.

Application of COMPONT Medical Adhesive Glue for Tension-Reduced Duraplasty in Decompressive Craniotomy

PubMed Central

Zhou, Yujia; Wang, Gesheng; Liu, Jialin; Du, Yong; Wang, Lei; Wang, Xiaoyong

2016-01-01

Background The aim of this study was to evaluate the application of medical adhesive glue for tension-reduced duraplasty in decompressive craniotomy. Material/Methods A total of 56 cases were enrolled for this study from Jan 2013 to May 2015. All patients underwent decompressive craniotomy and the dura was repaired in all of them with tension-reduced duraplasty using the COMPONT medical adhesive to glue artificial dura together. The postoperative complications and the healing of dura mater were observed and recorded. Results No wound infection, epidural or subdural hematoma, cerebrospinal fluid leakage, or other complications associated with the procedure occurred, and there were no allergic reactions to the COMPONT medical adhesive glue. The second-phase surgery of cranioplasty was performed at 3 to 6 months after the decompressive craniotomy in 32 out of the 56 cases. During the cranioplasty we observed no adherence of the artificial dura mater patch to the skin flap, no residual COMPONT glue, or hydropic or contracture change of tissue at the surgical sites. Additionally, no defect or weakening of the adherence between the artificial dura mater patch and the self dura matter occurred. Conclusions COMPONT medical adhesive glue is a safe and reliable tool for tension-reduced duraplasty in decompressive craniotomy. PMID:27752035

EFFECT OF HYDROPHILIC AND HYDROPHOBIC POLYMER ON IN VITRO DISSOLUTION AND PERMEATION OF BISOPROLOL FUMARATE THROUGH TRANSDERMAL PATCH.

PubMed

Shabbir, Maryam; Ali, Sajid; Raza, Moosa; Sharif, Ali; Akhtar, Furoan Muhammad; Manan, Abdul; Fazli, Ali Raza; Younas, Neelofar; Manzoor, Iqra

2017-01-01

A matrix transdermal patch of bisoprolol fumarate was formulated with different concentrations of Eudragit RS 100 and Methocel E5 with PEG 400 as plasticizer by solvent evaporation technique. Tween 80 was added to the optimized patch to evaluate the effect of permeation enhancer at different concentration through the excised rabbit's skin. The patches were analyzed for weight variation, drug content, swelling index, erosion studies, moisture content, moisture uptake, water vapor transmission rate (WVTR) and water vapor permeability (WVP). In vitro dissolution test was carried out in USP dissolution apparatus V to select the optimized formulation. In vitr skin permeation studies were done in Franz diffusion cell using rabbit skin as a model membrane. The cumulative drug release and flux were determined to compare the result of test patches with a control patch. The greatest enhancement ratio (ER) was obtained in F03-PE with 30% Tween 80. F03-PE seemed to follow zero order kinetics with super case II mechanism of drug release. Statistical ANOVA suggested that there was a significant difference in formulations, steady flux and cumulative permeation rate at different Tween 80 concentrations.

Reconstruction and simplification of urban scene models based on oblique images

NASA Astrophysics Data System (ADS)

Liu, J.; Guo, B.

2014-08-01

We describe a multi-view stereo reconstruction and simplification algorithms for urban scene models based on oblique images. The complexity, diversity, and density within the urban scene, it increases the difficulty to build the city models using the oblique images. But there are a lot of flat surfaces existing in the urban scene. One of our key contributions is that a dense matching algorithm based on Self-Adaptive Patch in view of the urban scene is proposed. The basic idea of matching propagating based on Self-Adaptive Patch is to build patches centred by seed points which are already matched. The extent and shape of the patches can adapt to the objects of urban scene automatically: when the surface is flat, the extent of the patch would become bigger; while the surface is very rough, the extent of the patch would become smaller. The other contribution is that the mesh generated by Graph Cuts is 2-manifold surface satisfied the half edge data structure. It is solved by clustering and re-marking tetrahedrons in s-t graph. The purpose of getting 2- manifold surface is to simply the mesh by edge collapse algorithm which can preserve and stand out the features of buildings.

A specialized face-processing model inspired by the organization of monkey face patches explains several face-specific phenomena observed in humans.

PubMed

Farzmahdi, Amirhossein; Rajaei, Karim; Ghodrati, Masoud; Ebrahimpour, Reza; Khaligh-Razavi, Seyed-Mahdi

2016-04-26

Converging reports indicate that face images are processed through specialized neural networks in the brain -i.e. face patches in monkeys and the fusiform face area (FFA) in humans. These studies were designed to find out how faces are processed in visual system compared to other objects. Yet, the underlying mechanism of face processing is not completely revealed. Here, we show that a hierarchical computational model, inspired by electrophysiological evidence on face processing in primates, is able to generate representational properties similar to those observed in monkey face patches (posterior, middle and anterior patches). Since the most important goal of sensory neuroscience is linking the neural responses with behavioral outputs, we test whether the proposed model, which is designed to account for neural responses in monkey face patches, is also able to predict well-documented behavioral face phenomena observed in humans. We show that the proposed model satisfies several cognitive face effects such as: composite face effect and the idea of canonical face views. Our model provides insights about the underlying computations that transfer visual information from posterior to anterior face patches.

A specialized face-processing model inspired by the organization of monkey face patches explains several face-specific phenomena observed in humans

PubMed Central

Farzmahdi, Amirhossein; Rajaei, Karim; Ghodrati, Masoud; Ebrahimpour, Reza; Khaligh-Razavi, Seyed-Mahdi

2016-01-01

Converging reports indicate that face images are processed through specialized neural networks in the brain –i.e. face patches in monkeys and the fusiform face area (FFA) in humans. These studies were designed to find out how faces are processed in visual system compared to other objects. Yet, the underlying mechanism of face processing is not completely revealed. Here, we show that a hierarchical computational model, inspired by electrophysiological evidence on face processing in primates, is able to generate representational properties similar to those observed in monkey face patches (posterior, middle and anterior patches). Since the most important goal of sensory neuroscience is linking the neural responses with behavioral outputs, we test whether the proposed model, which is designed to account for neural responses in monkey face patches, is also able to predict well-documented behavioral face phenomena observed in humans. We show that the proposed model satisfies several cognitive face effects such as: composite face effect and the idea of canonical face views. Our model provides insights about the underlying computations that transfer visual information from posterior to anterior face patches. PMID:27113635

Results of tests of K5NA and a revised formulation of EPDM/cork patch material in MSFC Hot Gas Facility

NASA Technical Reports Server (NTRS)

Dean, W. G.

1982-01-01

During prelaunch procedures at Kennedy Space Center some of the EPDM Thermal Protection System material was damaged on the Solid Rocket Booster stiffener stubs. The preferred solution was to patch the damaged areas with a cork-filled epoxy patching compound. Before this was done, however, it was requested that this patching technique be checked out by testing it in the MSFC Hot Gas Facility. Two tests were run in the HFG in 1980. The results showed the patch material to be adequate. Since that time, the formulation of the cork-filled epoxy material has been changed. It became necessary to retest this concept to be sure that the new material is as good as or better than the original material. In addition to the revised formulation material, tests were also made using K5NA as the patch material. The objectives of the tests reported herein were to: (1) compare the thermal performance of the original and the new cork-filled epoxy formulations, and (2) compare the K5NA closeout material to these epoxy materials. Material specifications are also discussed.

Inside-Out Meniscus Repair

PubMed Central

Nelson, Clay G.; Bonner, Kevin F.

2013-01-01

Meniscus repair over resection, when feasible, should be strongly considered in an effort to preserve meniscus integrity and function, especially in younger patients. Currently, a number of techniques and implants may be used to achieve a successful result. Although all-inside meniscus repair devices have evolved significantly since their introduction and have become the repair technique of choice for many surgeons, the classic inside-out repair technique is still very useful to have in one's armamentarium. Though less popular because of the ease of current-generation fixators, the inside-out technique can still offer advantages for those surgeons who are proficient. With the versatility to address most tear patterns, the ability to deliver sutures with smaller needle diameters, and proven long-term results, it has been considered the gold standard in meniscus repair. We review the inside-out repair technique for both a medial and lateral meniscus tear with some helpful tips when performing the technique, and we present a video demonstration of the lateral meniscus repair technique. PMID:24400199

Inherited Biotic Protection in a Neotropical Pioneer Plant

PubMed Central

Dejean, Alain; Corbara, Bruno; Leroy, Céline; Delabie, Jacques H. C.; Rossi, Vivien; Céréghino, Régis

2011-01-01

Chelonanthus alatus is a bat-pollinated, pioneer Gentianaceae that clusters in patches where still-standing, dried-out stems are interspersed among live individuals. Flowers bear circum-floral nectaries (CFNs) that are attractive to ants, and seed dispersal is both barochorous and anemochorous. Although, in this study, live individuals never sheltered ant colonies, dried-out hollow stems - that can remain standing for 2 years - did. Workers from species nesting in dried-out stems as well as from ground-nesting species exploited the CFNs of live C. alatus individuals in the same patches during the daytime, but were absent at night (when bat pollination occurs) on 60.5% of the plants. By visiting the CFNs, the ants indirectly protect the flowers - but not the plant foliage - from herbivorous insects. We show that this protection is provided mostly by species nesting in dried-out stems, predominantly Pseudomyrmex gracilis. That dried-out stems remain standing for years and are regularly replaced results in an opportunistic, but stable association where colonies are sheltered by one generation of dead C. alatus while the live individuals nearby, belonging to the next generation, provide them with nectar; in turn, the ants protect their flowers from herbivores. We suggest that the investment in wood by C. alatus individuals permitting still-standing, dried-out stems to shelter ant colonies constitutes an extended phenotype because foraging workers protect the flowers of live individuals in the same patch. Also, through this process these dried-out stems indirectly favor the reproduction (and so the fitness) of the next generation including both their own offspring and that of their siblings, all adding up to a potential case of inclusive fitness in plants. PMID:21483861

Atopy patch test reactions to house dust mites in patients with scabies.

PubMed

Taşkapan, Oktay; Harmanyeri, Yavuz

2005-01-01

It is well known that the house dust and the scabies mites are related phylogenetically. We therefore performed atopy patch tests with house dust mite antigens (Dermatophagoides pteronyssinus (Dp) and/or Dermatophagoides farinae (Df)) in scabies patients without atopy and healthy controls. We studied 25 men with active scabies and 25 healthy controls. Skin prick tests with standardized house dust mite extract were performed for all patients and controls. An intradermal test procedure was carried out in skin prick test-negative patients, and for controls showing positive atopy patch test to Dp and/or Df. While atopy patch tests were performed directly in all healthy controls, patients with scabies were first treated and on the next day, atopy patch tests were performed. Twenty-two of 25 patients with scabies (88%) had skin prick test and/or intradermal test positivity against house dust mites, whereas 17/25 patients (68%) had atopy patch test positivity against house dust mites (Dp and/or Df). There was no statistically significant difference between skin prick test and/or intradermal test positivity and atopy patch test positivity in a regression analysis (p=0.222). The only statistically significant correlation was between atopy patch test positivity and the extent of scabies involvement (p<0.05). Only few of the healthy controls had positive tests. In this study, we have shown that a positive atopy patch test to house dust mite antigens is not specific for patients with atopic dermatitis, but also occurs in scabies patients without a history of atopic dermatitis.

Patch-test reaction patterns in patients with a predisposition to atopic dermatitis.

PubMed

Brasch, Jochen; Schnuch, Axel; Uter, Wolfgang

2003-10-01

Patients with a predisposition to atopic dermatitis often need to be patch tested in order to detect possible contact sensitization. However, it is unknown whether immunologic or other peculiarities of atopic skin are related to altered patch-test reaction patterns. Our study was aimed at answering this question, because patch-test reaction patterns are of considerable practical importance in the reading and interpretation of patch tests. Therefore, we compared patterns of patch-test reactions in patients with a predisposition to atopic dermatitis and in control patients matched for sex, age, reason for testing and test centre. Patch-test results from 9 centres (2322 patients with a disposition to atopic dermatitis and 2126 matched controls) were evaluated retrospectively. All patients were tested with nickel sulfate, fragrance mix, potassium dichromate, lanolin alcohol, formaldehyde and mercury ammonium chloride. Patch tests applied for 1 day with readings on days 1, 2 and 3 were evaluated in order to cover the early phase of the reactions. Not unexpectedly, we found that, compared to the matched controls, patients with a predisposition to atopic dermatitis tended to have more doubtful and irritant reactions on day 1. As a new observation, it turned out that they had less reactions of crescendo pattern and more strong reactions on day 3. All these differences were slight/insignificant. A higher skin irritability in patients with a predisposition to atopic dermatitis is a likely explanation. In conclusion, standard methods for patch testing can be applied in patients with a predisposition to atopic dermatitis, but minor differences in reaction patterns should be considered.

Nlgn4 knockout induces network hypo-excitability in juvenile mouse somatosensory cortex in vitro.

PubMed

Delattre, V; La Mendola, D; Meystre, J; Markram, H; Markram, K

2013-10-09

Neuroligins (Nlgns) are postsynaptic cell adhesion molecules that form transynaptic complexes with presynaptic neurexins and regulate synapse maturation and plasticity. We studied the impact of the loss of Nlgn4 on the excitatory and inhibitory circuits in somatosensory cortical slices of juvenile mice by electrically stimulating these circuits using a multi-electrode array and recording the synaptic input to single neurons using the patch-clamp technique. We detected a decreased network response to stimulation in both excitatory and inhibitory circuits of Nlgn4 knock-out animals as compared to wild-type controls, and a decreased excitation-inhibition ratio. These data indicate that Nlgn4 is involved in the regulation of excitatory and inhibitory circuits and contributes to a balanced circuit response to stimulation.

hERG K+ channel-associated cardiac effects of the antidepressant drug desipramine.

PubMed

Staudacher, Ingo; Wang, Lu; Wan, Xiaoping; Obers, Sabrina; Wenzel, Wolfgang; Tristram, Frank; Koschny, Ronald; Staudacher, Kathrin; Kisselbach, Jana; Koelsch, Patrick; Schweizer, Patrick A; Katus, Hugo A; Ficker, Eckhard; Thomas, Dierk

2011-02-01

Cardiac side effects of antidepressant drugs are well recognized. Adverse effects precipitated by the tricyclic drug desipramine include prolonged QT intervals, torsade de pointes tachycardia, heart failure, and sudden cardiac death. QT prolongation has been primarily attributed to acute blockade of hERG/I(Kr) currents. This study was designed to provide a more complete picture of cellular effects associated with desipramine. hERG channels were expressed in Xenopus laevis oocytes and human embryonic kidney (HEK 293) cells, and potassium currents were recorded using patch clamp and two-electrode voltage clamp electrophysiology. Ventricular action potentials were recorded from guinea pig cardiomyocytes. Protein trafficking and cell viability were evaluated in HEK 293 cells and in HL-1 mouse cardiomyocytes by immunocytochemistry, Western blot analysis, or colorimetric MTT assay, respectively. We found that desipramine reduced hERG currents by binding to a receptor site inside the channel pore. hERG protein surface expression was reduced after short-term treatment, revealing a previously unrecognized mechanism. When long-term effects were studied, forward trafficking was impaired and hERG currents were decreased. Action potential duration was prolonged upon acute and chronic desipramine exposure. Finally, desipramine triggered apoptosis in cells expressing hERG channels. Desipramine exerts at least four different cellular effects: (1) direct hERG channel block, (2) acute reduction of hERG surface expression, (3) chronic disruption of hERG trafficking, and (4) induction of apoptosis. These data highlight the complexity of hERG-associated drug effects.

Use of ecoacoustics to determine biodiversity patterns across ecological gradients.

PubMed

Grant, Paul B C; Samways, Michael J

2016-12-01

The variety of local animal sounds characterizes a landscape. We used ecoacoustics to noninvasively assess the species richness of various biotopes typical of an ecofriendly forest plantation with diverse ecological gradients and both nonnative and indigenous vegetation. The reference area was an adjacent large World Heritage Site protected area (PA). All sites were in a global biodiversity hotspot. Our results showed how taxa segregated into various biotopes. We identified 65 singing species, including birds, frogs, crickets, and katydids. Large, natural, protected grassland sites in the PA had the highest mean acoustic diversity (14.1 species/site). Areas covered in nonnative timber or grass species were devoid of acoustic species. Sites grazed by native and domestic megaherbivores were fairly rich (5.1) in acoustic species but none were unique to this habitat type, where acoustic diversity was greater than in intensively managed grassland sites (0.04). Natural vegetation patches inside the plantation mosaic supported high mean acoustic diversity (indigenous forests 7.6, grasslands 8.0, wetlands 9.1), which increased as plant heterogeneity and patch size increased. Indigenous forest patches within the plantation mosaic contained a highly characteristic acoustic species assemblage, emphasizing their complementary contribution to local biodiversity. Overall, acoustic signals determined spatial biodiversity patterns and can be a useful tool for guiding conservation. © 2016 Society for Conservation Biology.

Design, Development, and Optimization of Dexibuprofen Microemulsion Based Transdermal Reservoir Patches for Controlled Drug Delivery

PubMed Central

Ali, Fatima Ramzan; Yousuf, Rabia Ismail; Ali, Syed Abid; Imtiaz, Muhammad Suleman; Bashir, Lubna; Naz, Shazia

2017-01-01

The aim of the study was to develop a reservoir-type transdermal patch for a controlled delivery of dexibuprofen and to evaluate its in vivo anti-inflammatory activity in Albino Wistar rats. In order to develop these patches, six formulations of dexibuprofen microemulsion comprising ethyl oleate, Tween 80: PG (2 : 1), and water were prepared by simplex lattice design and characterized. The reservoir compartment was filled with these microemulsions and in vitro release and skin permeation were assessed. The optimized patch was obtained on the basis of the responses: Q24 and flux. The impact of drug loading, surface area, membrane thickness, adhesive, and agitation speed on drug release and permeation was also studied. The skin sensitivity reaction and in vivo anti-inflammatory activity of optimized patch were evaluated. Stability study at three different temperatures for three months was carried out. The result suggests that a membrane based patch with zero-order release rate, Q24 of 79.13 ± 3.08%, and maximum flux of 331.17 µg/cm2h can be obtained exhibiting suitable anti-inflammatory activity with no visible skin sensitivity reaction. The outcomes of stability study recommend storage of patches at 4°C having shelf-life of 6.14 months. The study demonstrates that the reservoir-type transdermal patch of dexibuprofen microemulsion has a potential of delivering drug across skin in controlled manner with required anti-inflammatory activity. PMID:29090219

Modeling the Geographic Spread of Rabies in China

PubMed Central

Chen, Jing; Zou, Lan; Jin, Zhen; Ruan, Shigui

2015-01-01

In order to investigate how the movement of dogs affects the geographically inter-provincial spread of rabies in Mainland China, we propose a multi-patch model to describe the transmission dynamics of rabies between dogs and humans, in which each province is regarded as a patch. In each patch the submodel consists of susceptible, exposed, infectious, and vaccinated subpopulations of both dogs and humans and describes the spread of rabies among dogs and from infectious dogs to humans. The existence of the disease-free equilibrium is discussed, the basic reproduction number is calculated, and the effect of moving rates of dogs between patches on the basic reproduction number is studied. To investigate the rabies virus clades lineages, the two-patch submodel is used to simulate the human rabies data from Guizhou and Guangxi, Hebei and Fujian, and Sichuan and Shaanxi, respectively. It is found that the basic reproduction number of the two-patch model could be larger than one even if the isolated basic reproduction number of each patch is less than one. This indicates that the immigration of dogs may make the disease endemic even if the disease dies out in each isolated patch when there is no immigration. In order to reduce and prevent geographical spread of rabies in China, our results suggest that the management of dog markets and trades needs to be regulated, and transportation of dogs has to be better monitored and under constant surveillance. PMID:26020234

Astrocytes potentiate GABAergic transmission in the thalamic reticular nucleus via endozepine signaling.

PubMed

Christian, Catherine A; Huguenard, John R

2013-12-10

Emerging evidence indicates that diazepam-binding inhibitor (DBI) mediates an endogenous benzodiazepine-mimicking (endozepine) effect on synaptic inhibition in the thalamic reticular nucleus (nRT). Here we demonstrate that DBI peptide colocalizes with both astrocytic and neuronal markers in mouse nRT, and investigate the role of astrocytic function in endozepine modulation in this nucleus by testing the effects of the gliotoxin fluorocitrate (FC) on synaptic inhibition and endozepine signaling in the nRT using patch-clamp recordings. FC treatment reduced the effective inhibitory charge of GABAA receptor (GABAAR)-mediated spontaneous inhibitory postsynaptic currents in WT mice, indicating that astrocytes enhance GABAAR responses in the nRT. This effect was abolished by both a point mutation that inhibits classical benzodiazepine binding to GABAARs containing the α3 subunit (predominant in the nRT) and a chromosomal deletion that removes the Dbi gene. Thus, astrocytes are required for positive allosteric modulation via the α3 subunit benzodiazepine-binding site by DBI peptide family endozepines. Outside-out sniffer patches pulled from neurons in the adjacent ventrobasal nucleus, which does not contain endozepines, show a potentiated response to laser photostimulation of caged GABA when placed in the nRT. FC treatment blocked the nRT-dependent potentiation of this response, as did the benzodiazepine site antagonist flumazenil. When sniffer patches were placed in the ventrobasal nucleus, however, subsequent treatment with FC led to potentiation of the uncaged GABA response, suggesting nucleus-specific roles for thalamic astrocytes in regulating inhibition. Taken together, these results suggest that astrocytes are required for endozepine actions in the nRT, and as such can be positive modulators of synaptic inhibition.

Astrocytes potentiate GABAergic transmission in the thalamic reticular nucleus via endozepine signaling

PubMed Central

Christian, Catherine A.; Huguenard, John R.

2013-01-01

Emerging evidence indicates that diazepam-binding inhibitor (DBI) mediates an endogenous benzodiazepine-mimicking (endozepine) effect on synaptic inhibition in the thalamic reticular nucleus (nRT). Here we demonstrate that DBI peptide colocalizes with both astrocytic and neuronal markers in mouse nRT, and investigate the role of astrocytic function in endozepine modulation in this nucleus by testing the effects of the gliotoxin fluorocitrate (FC) on synaptic inhibition and endozepine signaling in the nRT using patch-clamp recordings. FC treatment reduced the effective inhibitory charge of GABAA receptor (GABAAR)-mediated spontaneous inhibitory postsynaptic currents in WT mice, indicating that astrocytes enhance GABAAR responses in the nRT. This effect was abolished by both a point mutation that inhibits classical benzodiazepine binding to GABAARs containing the α3 subunit (predominant in the nRT) and a chromosomal deletion that removes the Dbi gene. Thus, astrocytes are required for positive allosteric modulation via the α3 subunit benzodiazepine-binding site by DBI peptide family endozepines. Outside-out sniffer patches pulled from neurons in the adjacent ventrobasal nucleus, which does not contain endozepines, show a potentiated response to laser photostimulation of caged GABA when placed in the nRT. FC treatment blocked the nRT-dependent potentiation of this response, as did the benzodiazepine site antagonist flumazenil. When sniffer patches were placed in the ventrobasal nucleus, however, subsequent treatment with FC led to potentiation of the uncaged GABA response, suggesting nucleus-specific roles for thalamic astrocytes in regulating inhibition. Taken together, these results suggest that astrocytes are required for endozepine actions in the nRT, and as such can be positive modulators of synaptic inhibition. PMID:24262146

A hydrophilic polymer based microfluidic system with planar patch clamp electrode array for electrophysiological measurement from cells.

PubMed

Xu, Baojian; Ye, WeiWei; Zhang, Yu; Shi, JingYu; Chan, ChunYu; Yao, XiaoQiang; Yang, Mo

2014-03-15

This paper presents a microfluidic planar patch clamp system based on a hydrophilic polymer poly(ethylene glycol) diacrylate (PEGDA) for whole cell current recording. The whole chip is fabricated by UV-assisted molding method for both microfluidic channel structure and planar electrode partition. This hydrophilic patch clamp chip has demonstrated a relatively high gigaseal success rate of 44% without surface modification compared with PDMS based patch clamp devices. This chip also shows a capability of rapid intracellular and extracellular solution exchange with high stability of gigaseals. The capillary flow kinetic experiments demonstrate that the flow rates of PEGDA microfluidic channels are around two orders of magnitude greater than those for PDMS-glass channels with the same channel dimensions. This hydrophilic polymer based patch clamp chips have significant advantages over current PDMS elastomer based systems such as no need for surface modification, much higher success rate of cell gigaseals and rapid solution exchange with stable cell gigaseals. Our results indicate the potential of these devices to serve as useful tools for pharmaceutical screening and biosensing tasks. © 2013 Elsevier B.V. All rights reserved.

Odorant responses of olfactory sensory neurons expressing the odorant receptor MOR23: A patch clamp analysis in gene-targeted mice

PubMed Central

Grosmaitre, Xavier; Vassalli, Anne; Mombaerts, Peter; Shepherd, Gordon M.; Ma, Minghong

2006-01-01

A glomerulus in the mammalian olfactory bulb receives axonal inputs from olfactory sensory neurons (OSNs) that express the same odorant receptor (OR). Glomeruli are generally thought to represent functional units of olfactory coding, but there are no data on the electrophysiological properties of OSNs that express the same endogenous OR. Here, using patch clamp recordings in an intact epithelial preparation, we directly measured the transduction currents and receptor potentials from the dendritic knobs of mouse OSNs that express the odorant receptor MOR23 along with the green fluorescent protein. All of the 53 cells examined responded to lyral, a known ligand for MOR23. There were profound differences in response kinetics, particularly in the deactivation phase. The cells were very sensitive to lyral, with some cells responding to as little as 10 nM. The dynamic range was unexpectedly broad, with threshold and saturation in individual cells often covering three log units of lyral concentration. The potential causes and biological significance of this cellular heterogeneity are discussed. Patch clamp recording from OSNs that express a defined OR provides a powerful approach to investigate the sensory inputs to individual glomeruli. PMID:16446455

Odorant responses of olfactory sensory neurons expressing the odorant receptor MOR23: a patch clamp analysis in gene-targeted mice.

PubMed

Grosmaitre, Xavier; Vassalli, Anne; Mombaerts, Peter; Shepherd, Gordon M; Ma, Minghong

2006-02-07

A glomerulus in the mammalian olfactory bulb receives axonal inputs from olfactory sensory neurons (OSNs) that express the same odorant receptor (OR). Glomeruli are generally thought to represent functional units of olfactory coding, but there are no data on the electrophysiological properties of OSNs that express the same endogenous OR. Here, using patch clamp recordings in an intact epithelial preparation, we directly measured the transduction currents and receptor potentials from the dendritic knobs of mouse OSNs that express the odorant receptor MOR23 along with the green fluorescent protein. All of the 53 cells examined responded to lyral, a known ligand for MOR23. There were profound differences in response kinetics, particularly in the deactivation phase. The cells were very sensitive to lyral, with some cells responding to as little as 10 nM. The dynamic range was unexpectedly broad, with threshold and saturation in individual cells often covering three log units of lyral concentration. The potential causes and biological significance of this cellular heterogeneity are discussed. Patch clamp recording from OSNs that express a defined OR provides a powerful approach to investigate the sensory inputs to individual glomeruli.

Low-cost grass restoration using erosion barriers in a degraded African rangeland

USGS Publications Warehouse

Kimiti, David W; Riginos, Corinna; Belnap, Jayne

2017-01-01

Rangeland degradation, typified by extensive bare ground and soil erosion, is a serious problem around the world. In sub-Saharan Africa, rangeland degradation threatens the food security of millions of people who depend on livestock and the region's large mammalian wildlife diversity. We tested the ability of five simple, low-cost erosion barriers to promote grass and forb establishment in a bare ground-dominated rangeland in Kenya. These treatments were: (1) trenches with small berms; (2) bundles of branches; and bundles of branches with (3) elephant dung balls, (4) burlap sacking, or (5) nylon mesh sacking inside them. We also tested whether barrier performance depended on (1) supplemental seeding with the grass Cenchrus ciliaris and (2) whether a barrier was located next to existing vegetation patches versus in the open. Within months, the trench and nylon mesh barriers had accumulated 20–50% more sediment than other treatments and had greater grass and forb seedling establishment. Seeding with Cenchrusresulted in higher herbaceous cover but was not necessary for other grasses to establish. After 3 years, the trench and nylon mesh barriers had created patches of new vegetation averaging 18–63% larger than patches created by the other treatments. Barriers that were initially adjacent to existing vegetation had created new vegetation patches averaging 65% larger than those created by solitary barriers. Results suggest that all barrier types increase grass cover but that trenches—especially if placed next to existing vegetation patches—are a particularly cost-effective way to reduce bare ground and erosion in degraded rangelands.

[Epidemiology of contact hypersensitivity to rubber components in manufacturers of automobile tires at the Stomil plant].

PubMed

Rubisz-Brzezińska, J; Bogdanowski, T; Brzezińska-Wcisło, L; Mozdzanowska, K; Bajcar, S

1990-01-01

Dermatological examination and patch tests with 34 rubber components were carried out in 114 tire manufacturers, 78 women and 36 men aged 29 years on average, with a mean duration of work in the plant 7 years. For correct interpretation of the obtained results patch tests with the same components were done in two control groups that is in 120 healthy subjects and 120 patients with contact dermatitis. Patch tests with proper concentrations of the studied components were evaluated after 48, 72 and 96 hours. Positive patch tests were found most frequently with antioxidants--16.6% (including IPPD--8.6%), followed by vulcanization accelerators--10.6%, and other rubber components--11.4% in all. During about 3 years of follow-up in 4 manufacturers contact allergic eczema was noted and polyvalent hypersensitivity to antioxidants and vulcanization accelerators without clinical manifestations of this hypersensitivity was diagnosed in 3 other subjects.

Patch-test reactions to plastic and glue allergens.

PubMed

Kanerva, L; Jolanki, R; Alanko, K; Estlander, T

1999-07-01

Plastics and glues are common causes of occupational dermatoses, but only few reports have dealt with patch-test reactions caused by plastic and glue allergens. Patients exposed to plastics and remitted to an occupational dermatology clinic, were patch-tested with 50-53 plastic and glue allergens during a 6-year period. Conventional patch-test techniques were used. The most common causes of allergic patch-test reactions in 360 patients were novolac epoxy resin (5.1%), phenol formaldehyde resin (3.1%), 4-tert-butylcatechol (2.6%), phenyl glycidyl ether (2.6%), diaminodiphenyl methane (2.2%), benzoyl peroxide (2.2%), hexamethylene tetramine (2.0%) and o-cresyl glycidyl ether (1.6%). The allergens that most often elicited irritant patch-test reactions were: benzoyl peroxide (9.5%), abitol alcohol (3.6%), hydroquinone (3.1%), acid-catalyzed phenol formaldehyde resin (2.5%) and toluene diisocyanate (1.9%). Twenty-six out of 53 chemicals caused no allergic reaction during the 6-year period. Plastic allergens in the standard series provoked allergic reactions with formaldehyde (5.8%), diglycidyl ether of bisphenol A (3.2%), 4-tert-butylphenol-formaldehyde-resin (1.1%), toluene sulphonamide formaldehyde-resin (1.1%) and triethylenglycol diacrylate (0.4%). Although half of the plastic chemicals gave no allergic patch-test reactions during a 6-year period, with unusual allergens this low yield needs to be accepted, because otherwise rare allergies will not be detected. Also a negative reaction has diagnostic value.

Common Allergens Identified Based on Patch Test Results in Patients with Suspected Contact Dermatitis of the Scalp

PubMed Central

Aleid, Nouf M.; Fertig, Raymond; Maddy, Austin; Tosti, Antonella

2017-01-01

Background Contact dermatitis of the scalp is common and might be caused by many chemicals including metals, ingredients of shampoos and conditioners, dyes, or other hair treatments. Eliciting a careful history and patch tests are necessary to identify the responsible allergen and prevent relapses. Objectives To identify allergens that may cause contact dermatitis of the scalp by reviewing patch test results. Methods We reviewed the records of 1,015 patients referred for patch testing at the Dermatology Department of the University of Miami. A total of 226 patients (205 females and 21 males) with suspected scalp contact dermatitis were identified, and the patch test results and clinical data for those patients were analyzed. Most patients were referred for patch testing from a specialized hair clinic at our institution. Results The most common allergens in our study population were nickel (23.8%), cobalt (21.0%), balsam of Peru (18.2%), fragrance mix (14.4%), carba mix (11.6%), and propylene glycol (PG) (8.8%). The majority of patients were females aged 40–59 years, and scalp itching or burning were reported as the most common symptom. Conclusion Frequent sources of allergens for metals include hair clasps, pins, and brushes, while frequent sources of allergens for preservatives, fragrance mix, and balsam of Peru include shampoos, conditioners, and hair gels. Frequent sources of allergens for PG include topical medications. PMID:28611994

Galaxies Grow from Inside Out

NASA Image and Video Library

2013-10-31

Evidence from NASA Wide-field Infrared Survey Explorer and Galaxy Evolution Explorer missions provide support for the inside-out theory of galaxy evolution, which holds that star formation starts at the core of the galaxy and spreads outward.

Insect Optic Glomeruli-Exploration of a Universal Circuit for Sensorimotor Processing

DTIC Science & Technology

2011-01-25

09 to 2-28-10. We have successfully achieved the first recordings from any laboratory of the small palisade output neurons from the lobula of...glomeruli. Using infrared illumination and optics, the cell bodies of such clones are directly observed. A patch clamp recording electrode, filled...neuron and electrolyte of the electrode has been established, the cell is recorded during the presentation of a sequence of visual stimuli: stripes

Hydrodynamic Mediation of Killifish Predation on Infaunal Polychaetes

NASA Astrophysics Data System (ADS)

Hentschel, B. T.; Hayman, N. T.; Anderson, T. W.

2016-02-01

To explore predator-prey interactions between California killifish (Fundulus parvipinnis) and spionid polychaetes (Polydora cornuta and Streblospio benedicti) in tidal creeks, we conducted a laboratory flume experiment to quantify whether killifish prey-patch selectivity varies with flow speed. The flume included a 300-cm2 area of defaunated sediment within which we centrally positioned 24 P. cornuta, 24 S. benedicti, or no worms as a prey-free control. We videotaped groups of three killifish for 50 min at one of six unidirectional flow speeds (3, 6, 9, 12, 15, or 18 cm/s measured 1.5 cm above bottom) and recorded their bite rate anywhere in the sediment area vs. bites directed at the central prey patch (98 cm2). Each flow speed and prey treatment was replicated by four independent flume runs (i.e., 72 total flume runs). The percentage of bites directed at the central patch varied significantly with flow speed and worm presence. With defaunated sediment only, 33% of bites were directed at the central patch at all flow speeds, consistent with a null model of non-selective foraging. When either worm species inhabited the central patch, 65% of bites were directed at the central patch at 3 and 6 cm/s, and patch selectivity declined linearly as flow increased. Despite differences in morphology and behavior, the two prey species elicited similar foraging activity by killifish. We pooled the P. cornuta and S. benedicti treatments to determine the flow speed at which prey-patch selectivity by killifish became statistically indistinguishable from non-selective biting in the absence of prey. At flow speeds of 3, 6, and 9 cm/s, the percentage of bites located in the 98-cm2 patch was significantly greater when live worms were present compared to the prey-free controls. At 12, 15, and 18 cm/s, there was not a significant difference between the control patches and those containing live worms, indicating 12 cm/s is a flow threshold above which killifish cannot selectively forage on dense patches of infauna.

Stiffness and strength of fiber reinforced polymer composite bridge deck systems

NASA Astrophysics Data System (ADS)

Zhou, Aixi

This research investigates two principal characteristics that are of primary importance in Fiber Reinforced Polymer (FRP) bridge deck applications: STIFFNESS and STRENGTH. The research was undertaken by investigating the stiffness and strength characteristics of the multi-cellular FRP bridge deck systems consisting of pultruded FRP shapes. A systematic analysis procedure was developed for the stiffness analysis of multi-cellular FRP deck systems. This procedure uses the Method of Elastic Equivalence to model the cellular deck as an equivalent orthotropic plate. The procedure provides a practical method to predict the equivalent orthotropic plate properties of cellular FRP decks. Analytical solutions for the bending analysis of single span decks were developed using classical laminated plate theory. The analysis procedures can be extended to analyze continuous FRP decks. It can also be further developed using higher order plate theories. Several failure modes of the cellular FRP deck systems were recorded and analyzed through laboratory and field tests and Finite Element Analysis (FEA). Two schemes of loading patches were used in the laboratory test: a steel patch made according to the ASSHTO's bridge testing specifications; and a tire patch made from a real truck tire reinforced with silicon rubber. The tire patch was specially designed to simulate service loading conditions by modifying real contact loading from a tire. Our research shows that the effects of the stiffness and contact conditions of loading patches are significant in the stiffness and strength testing of FRP decks. Due to the localization of load, a simulated tire patch yields larger deflection than the steel patch under the same loading level. The tire patch produces significantly different failure compared to the steel patch: a local bending mode with less damage for the tire patch; and a local punching-shear mode for the steel patch. A deck failure function method is proposed for predicting the failure of FRP decks. Using developed laminated composite theories and FEA techniques, a strength analysis procedure containing ply-level information was proposed and detailed for FRP deck systems. The behavior of the deck's unsupported (free) edges was also investigated using ply-level FEA.

Regulation of ATP sensitive potassium channel of isolated guinea pig ventricular myocytes by sarcolemmal monocarboxylate transport.

PubMed

Coetzee, W A

1992-11-01

The aim was to describe the effects of extracellular application of monocarboxylates (pyruvate, lactate, or acetate) on current through KATP channels (iK,ATP) in isolated guinea pig ventricular myocytes. The iK,ATP was elicited during whole cell voltage clamping by application of metabolic poisons, 2,4-dinitrophenol (150 microM) or glucose free cyanide (1 mM) and could be blocked by glibenclamide (3 microM). Extracellular application of monocarboxylates, pyruvate (0.1-10 mM), L-lactate (0.1-10 mM), and acetate (10 mM) led to a rapid inhibition of iK,ATP--an effect which was fully reversible upon washout. Substances without any effect on iK,ATP were (10 mM each) gluconate, citrate, glutamate, creatine, succinate, and glycine. The mechanism underlying the effects of monocarboxylates on iK,ATP was unlikely to be related to an increased ATP production, since D-lactate (10 mM) essentially had the same effect on iK,ATP as the L-isomer of lactate. Furthermore, with intracellular dialysis of alpha-cyano-4-hydroxycinnamate (0.1-0.5 mM), which inhibits pyruvate uptake into mitochondria, extracellular pyruvate exerted the same inhibitory effect on iK,ATP. High concentrations of extracellular alpha-cyano-4-hydroxycinnamate (4 mM), which blocks the sarcolemmal monocarboxylate carrier, prevented the effects on iK,ATP by pyruvate, L-lactate, D-lactate, and acetate. Furthermore, intracellular dialysis with D-lactate (10 mM) led to a more rapid onset of iK,ATP when activated by ATP free dialysis. Activity of isolated KATP channels, measured in isolated membrane patches in the inside out or outside out configuration, typically had a single channel conductance of around 80 pS and was blocked by glibenclamide (3-9 microM). No significant effect of pyruvate was observed in either patch configuration. In cardiac tissue there may be some modulatory role involving monocarboxylate transport on KATP channel activity, the nature of which is unclear at present but which may involve cytosolic pH changes. Physiological and pathophysiological implications of these findings are discussed.

Magnetophoresis for enhancing transdermal drug delivery: Mechanistic studies and patch design

PubMed Central

Murthy, S. Narasimha; Sammeta, Srinivasa M.; Bower, C.

2017-01-01

Magnetophoresis is a method of enhancement of drug permeation across the biological barriers by application of magnetic field. The present study investigated the mechanistic aspects of magnetophoretic transdermal drug delivery and also assessed the feasibility of designing a magnetophoretic transdermal patch system for the delivery of lidocaine. In vitro drug permeation studies were carried out across the porcine epidermis at different magnetic field strengths. The magnetophoretic drug permeation “flux enhancement factor” was found to increase with the applied magnetic field strength. The mechanistic studies revealed that the magnetic field applied in this study did not modulate permeability of the stratum corneum barrier. The predominant mechanism responsible for magnetically mediated drug permeation enhancement was found to be “magnetokinesis”. The octanol/water partition coefficient of drugs was also found to increase when exposed to the magnetic field. A reservoir type transdermal patch system with a magnetic backing was designed for in vivo studies. The dermal bioavailability (AUC0–6 h) from the magnetophoretic patch system in vivo, in rats was significantly higher than the similarly designed nonmagnetic control patch. PMID:20728484

Marine mammal tracks from two-hydrophone acoustic recordings made with a glider

NASA Astrophysics Data System (ADS)

Küsel, Elizabeth T.; Munoz, Tessa; Siderius, Martin; Mellinger, David K.; Heimlich, Sara

2017-04-01

A multinational oceanographic and acoustic sea experiment was carried out in the summer of 2014 off the western coast of the island of Sardinia, Mediterranean Sea. During this experiment, an underwater glider fitted with two hydrophones was evaluated as a potential tool for marine mammal population density estimation studies. An acoustic recording system was also tested, comprising an inexpensive, off-the-shelf digital recorder installed inside the glider. Detection and classification of sounds produced by whales and dolphins, and sometimes tracking and localization, are inherent components of population density estimation from passive acoustics recordings. In this work we discuss the equipment used as well as analysis of the data obtained, including detection and estimation of bearing angles. A human analyst identified the presence of sperm whale (Physeter macrocephalus) regular clicks as well as dolphin clicks and whistles. Cross-correlating clicks recorded on both data channels allowed for the estimation of the direction (bearing) of clicks, and realization of animal tracks. Insights from this bearing tracking analysis can aid in population density estimation studies by providing further information (bearings), which can improve estimates.

Design and characterisation of miniaturised cavity-backed patch antenna for microwave hyperthermia.

PubMed

Chakaravarthi, Geetha; Arunachalam, Kavitha

2015-01-01

The aim of this study was to describe the design and characterisation of a miniaturised 434 MHz patch antenna enclosed in a metal cavity for microwave hyperthermia treatment of cancer. Electromagnetic (EM) field distribution in the near field of a microstrip patch irradiating body tissue was studied using finite element method (FEM) simulations. Antenna miniaturisation was achieved through dielectric loading with very high permittivity, metal enclosure, patch folding and shorting post. Frequency dependent electrical properties of materials were incorporated wherever appropriate using dispersion model and measurements. Antenna return loss and specific absorption rate (SAR) at 434 MHz were measured on muscle phantoms for characterisation. The design was progressively optimised to yield a compact 434 MHz patch (22 mm × 8.8 mm × 10 mm) inside a metal cavity (40 mm × 12 mm) with integrated coupling water bolus (35 mm). The fabricated antenna with integrated water bolus was self resonant at 434 MHz without load, and has better than -10 dB return loss (S11) with 13-20 MHz bandwidth on two different phantoms. SAR at 434 MHz measured using an infrared (IR) thermal camera on split phantoms indicated penetration depth for -3 dB SAR as 8.25 mm compared to 8.87 mm for simulation. The simulated and measured SAR coverage along phantom depth was 3.09 cm(2) and 3.21 cm(2) respectively at -3 dB, and 6.42 cm(2) and 9.07 cm(2) respectively at -6 dB. SAR full width at half maximum (FWHM) at 5 mm and 20 mm depths were 54.68 mm and 51.18 mm respectively in simulation, and 49.47 mm and 43.75 mm respectively in experiments. Performance comparison of the cavity-backed patch indicates more than 89% co-polarisation and higher directivity which resulted in deeper penetration compared to the patch applicators of similar or larger size proposed for hyperthermia treatment of cancer. The fabricated cavity-backed applicator is self-resonant at 434 MHz with a negligible shift in resonance when coupled to different phantoms, Δf/f0 less than 1.16%. IR thermography-based SAR measurements indicated that the -3 dB SAR of the cavity-backed aperture antenna covered the radiating aperture surface at 5 mm and 20 mm depths. It can be concluded that the compact cavity-backed patch antenna has stable resonance, higher directivity and low cross polarisation, and is suitable for design of microwave hyperthermia array applicators with adjustable heating pattern for superficial and/or deep tissue heating.

Enhancement of transdermal protein delivery by photothermal effect of gold nanorods coated on polysaccharide-based hydrogel.

PubMed

Haine, Aung Thu; Koga, Yuki; Hashimoto, Yuta; Higashi, Taishi; Motoyama, Keiichi; Arima, Hidetoshi; Niidome, Takuro

2017-10-01

Transdermal protein delivery is a useful and attractive method for protein therapy and dermal vaccination. However, this delivery method is restricted by the low permeability of the stratum corneum. The purpose of this study was to develop a transdermal delivery system for enhancement of protein permeability into the skin. First, we prepared a transparent gel patch made of polysaccharides with gold nanorods on the gel surface and fluorescein isothiocyanate-modified ovalbumin (FITC-OVA) inside. Next, the gel patch was placed on mouse skin to allow contact with the coated gold nanorods, and irradiated by a continuous-wave laser. The laser irradiation heated the gold nanorods and the skin temperature increased to 43°C, resulting in enhanced translocation of FITC-OVA into the skin. These results confirmed the capability of the transdermal protein delivery system to perforate the stratum corneum and thus facilitate the passage of proteins across the skin. Copyright © 2017 Elsevier B.V. All rights reserved.

Dimethyl fumarate contact dermatitis of the foot: an increasingly widespread disease.

PubMed

D'Erme, Angelo Massimiliano; Bassi, Andrea; Lotti, Torello; Gola, Massimo

2012-01-01

Dimethyl fumarate (DMF) has been recognized as an extremely potent irritant and sensitizer found in sachets inside furniture. The first skin manifestations were correlated to contact with sofas, chairs, and other furniture. In these last years, some papers have reported a development of allergic contact dermatitis on the foot caused by DMF present in high concentration in shoes made in China. We report the case of a 37-year-old woman who presented with severe eczema on the foot shortly after having bought a new pair of shoes. The diagnosis was performed by patch tests with DMF in several dilutions, with pieces of internal and external parts of the shoes, and by chemical analysis of the shoes. In the last three years, goods containing DMF increased diffusely despite the augmentation on global preventive measures by Europe. Therefore, new cases of contact dermatitis could be dependent on DMF, and it is of note that this allergen is not included in most series for patch testing. © 2011 The International Society of Dermatology.

Earth observations taken during the STS-71 mission

NASA Image and Video Library

1995-07-06

STS071-708-040 (27 June-7 July 1995) --- This view shows Cape Cod in some detail in the center right of the view. Provincetown lies on the inside of the hook of Cape Cod. Other larger cities are unusually easy to see on this frame. The Boston metropolitan area is the large gray area at the top (north), with a smaller gray patch immediately south indicating Brockton, Massachusetts. Other smaller patches in southern Massachusetts (bottom left) indicate Fall River (far left) and New Bedford in the coast on the north side of Buzzard's Bay. The outskirts of Providence, Rhode Island appear half way up the left edge of the frame. The islands at the bottom of the frame are Martha's Vineyard (bottom left) and Nantucket Island (partial view). Shoals (near-surface sand bars) appear as light-blue swirls on the shallow sea bottom between Cape Cod and these islands. The distance from Boston to Nantucket is almost 100 miles.

Towards causal patch physics in dS/CFT

NASA Astrophysics Data System (ADS)

Neiman, Yasha

2018-01-01

This contribution is a status report on a research program aimed at obtaining quantum-gravitational physics inside a cosmological horizon through dS/CFT, i.e. through a holographic description at past/future infinity of de Sitter space. The program aims to bring together two main elements. The first is the observation by Anninos, Hartman and Strominger that Vasiliev's higher-spin gravity provides a working model for dS/CFT in 3+1 dimensions. The second is the proposal by Parikh, Savonije and Verlinde that dS/CFT may prove more tractable if one works in so-called "elliptic" de Sitter space - a folded-in-half version of global de Sitter where antipodal points have been identified. We review some relevant progress concerning quantum field theory on elliptic de Sitter space, higher-spin gravity and its holographic duality with a free vector model. We present our reasons for optimism that the approach outlined here will lead to a full holographic description of quantum (higher-spin) gravity in the causal patch of a de Sitter observer.

An optimization based study of equivalent circuit models for representing recordings at the neuron-electrode interface

PubMed Central

Thakore, Vaibhav; Molnar, Peter; Hickman, James J.

2014-01-01

Extracellular neuroelectronic interfacing is an emerging field with important applications in the fields of neural prosthetics, biological computation and biosensors. Traditionally, neuron-electrode interfaces have been modeled as linear point or area contact equivalent circuits but it is now being increasingly realized that such models cannot explain the shapes and magnitudes of the observed extracellular signals. Here, results were compared and contrasted from an unprecedented optimization based study of the point contact models for an extracellular ‘on-cell’ neuron-patch electrode and a planar neuron-microelectrode interface. Concurrent electrophysiological recordings from a single neuron simultaneously interfaced to three distinct electrodes (intracellular, ‘on-cell’ patch and planar microelectrode) allowed novel insights into the mechanism of signal transduction at the neuron-electrode interface. After a systematic isolation of the nonlinear neuronal contribution to the extracellular signal, a consistent underestimation of the simulated supra-threshold extracellular signals compared to the experimentally recorded signals was observed. This conclusively demonstrated that the dynamics of the interfacial medium contribute nonlinearly to the process of signal transduction at the neuron-electrode interface. Further, an examination of the optimized model parameters for the experimental extracellular recordings from sub- and supra-threshold stimulations of the neuron-electrode junctions revealed that ionic transport at the ‘on-cell’ neuron-patch electrode is dominated by diffusion whereas at the neuron-microelectrode interface the electric double layer (EDL) effects dominate. Based on this study, the limitations of the equivalent circuit models in their failure to account for the nonlinear EDL and ionic electrodiffusion effects occurring during signal transduction at the neuron-electrode interfaces are discussed. PMID:22695342

Experiments on selection of feeding site and food size in oystercatchers, Haematopus ostralegus, of different social status

NASA Astrophysics Data System (ADS)

Leopold, M. F.; Swennen, C.; De Bruijn, L. L. M.

Oystercatchers, Haematopus ostralegus, were tested for size selection in two prey species, cockles ( Cerastoderma edule) and mussels ( Mytilus edulis), under semi-natural, but strictly experimental, conditions that allowed recovery of all shells of prey items eaten. Within any patch of cockles offered, size was not an important selection criterion for the birds. The mean length of cockles consumed always differed less than 1 mm (the measuring accuracy) from the mean length of the cockles presented. When given a choice between patches of different prey quality, the birds tended to select patches according to their relative dominance status, with the most dominant bird feeding mainly in the patch where the prey items had the largest flesh contents. Less dominant birds were forced out of the preferred patch and obtained most of theif food from a patch of presumedly lower quality. One of these birds adapted its prey-handling method and its bill shape for efficient feeding in such a low quality pathc, and it continued feeding in that patch, even after the dominant conspecifics had been removed. In experiments with mussels as prey, the test bird did not select primarily on the basis of size but tended to eat those mussels that were easiest to open. It is concluded that size selection in oystercatchers that eat either cockles or mussels ends with the choice of a certain foraging patch. Within a patch of cockles of one year-class, which is the field condition for the majority of oystercatchers in the Wadden Sea, no selection for size occurs, because this would take too much extra searching time to be profitable.

Analytical study of inside-out Gimbal dynamics. Volume 2: Appendix

NASA Technical Reports Server (NTRS)

Rybak, S. C.

1976-01-01

Stability data, eigenvalue data, and instrument pointing system earth point tracking time histories at various orbital altitudes are presented. These data apply to the inside-out Gimbal system configuration and the coincident Gimbal system configuration.

Offshore Membrane Enclosure for Growing Algai (Omega) System for Biofuel Production, Wastewater Treatment, and CO2 Sequestration

NASA Technical Reports Server (NTRS)

Trent, Jonathan; Embaye, Tsegereda; Buckwalter, Patrick; Richardson, Tra-My; Kagawa, Hiromi; Reinsch, Sigrid

2010-01-01

We are developing Offshore Membrane Enclosures for Growing Algae (OMEGA). OMEGAs are closed photo-bioreactors constructed of flexible, inexpensive, and durable plastic with small sections of semi-permeable membranes for gas exchange and forward osmosis (FO). Each OMEGA modules is filled with municipal wastewater and provided with CO2 from coastal CO2 sources. The OMEGA modules float just below the surface, and the surrounding seawater provides structural support, temperature control, and mixing for the freshwater algae cultures inside. The salinity gradient from inside to outside drives forward osmosis through the patches of FO membranes. This concentrates nutrients in the wastewater, which enhances algal growth, and slowly dewaters the algae, which facilitates harvesting. The concentrated algal biomass is harvested for producing biofuels and fertilizer. OMEGA system cleans the wastewater released into the surrounding coastal waters and functions as a carbon sequestration system.

Offshore Membrane Enclosures for Growing Algae (OMEGA: A System for Biofuel Production, Wastewater Treatment, and CO2 Sequestration

NASA Technical Reports Server (NTRS)

Trent, Jonathan; Embaye, Tsegereda; Buckwalter, Patrick; Richardson, Tra-My; Kagawa, Hiromi; Reinsch, Sigrid; Martis, Mary

2010-01-01

We are developing Offshore Membrane Enclosures for Growing Algae (OMEGA). OMEGAs are closed photo-bioreactors constructed of flexible, inexpensive, and durable plastic with small sections of semi-permeable membranes for gas exchange and forward osmosis (FO). Each OMEGA modules is filled with municipal wastewater and provided with CO2 from coastal CO2 sources. The OMEGA modules float just below the surface, and the surrounding seawater provides structural support, temperature control, and mixing for the freshwater algae cultures inside. The salinit7 gradient from inside to outside drives forward osmosis through the patches of FO membranes. This concentrates nutrients in the wastewater, which enhances algal growth, and slowly dewaters the algae, which facilitates harvesting. Thy concentrated algal biomass is harvested for producing biofuels and fertilizer. OMEGA system cleans the wastewater released into the surrounding coastal waters and functions as a carbon sequestration system.

Tubular growth and bead formation in the lyotropic lamellar phase of a lipid.

PubMed

Bhatia, Tripta; Hatwalne, Yashodhan; Madhusudana, N V

2015-07-28

We use fluorescence confocal polarised microscopy (FCPM) to study tubular growth upon hydration of dry DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine) in water and water-glycerol mixtures. We have developed a model to relate the FCPM intensity profiles to the multilamellar structures of the tubules. Insertion of an additional patch inside a tubule produces a beaded structure, while a straight configuration is retained if the growth is on the outside. We use a simple model to suggest that reduction in overall curvature energy drives bead formation.

Pharmacokinetic overview of ethinyl estradiol dose and bioavailability using two transdermal contraceptive systems and a standard combined oral contraceptive

PubMed Central

Hofmann, Birte; Reinecke, Isabel; Schuett, Barbara; Merz, Martin; Zurth, Christian

2014-01-01

Objective: To determine the relative bioavailability of ethinyl estradiol (EE) and gestodene (GSD) after application of a novel transdermal contraceptive patch vs. a standard combined oral contraceptive (COC) pill (study 1), and to evaluate the pharmacokinetics (PK) of EE after application of the EE/GSD patch compared with an EE/norelgestromin (NGMN) patch (study 2). Materials: Participants were healthy, non-obese women aged 18 – 45 years (study 1) or 18 – 35 years (study 2). Compositions of study treatments were as follows: 0.55 mg EE/2.1 mg GSD (EE/GSD patch); 0.02 mg EE/0.075 mg GSD (standard COC); 0.6 mg EE/6 mg NGMN (EE/NGMN patch). Methods: In study 1, which consisted of 3 treatment periods (each followed by 7 patch- or pill-free days), treatments were administered in one of two randomized orders: either P–M–E (EE/GSD patch (P) every 7 days for 28 days → COC (M) once-daily for 21 days → two 7-day patch-wearing periods followed by one 10-day patch-wearing phase (E)), or the same treatments administered in sequence M–P–E. For study 2, participants received either the EE/GSD patch or EE/NGMN patch for seven treatment cycles (one patch per week for 3 weeks followed by a 7-day patch-free interval). Results: In study 1, average daily exposure to EE was similar for treatments P and M; the mean daily area under the concentration-time curve (AUC) ratio of treatment P vs. treatment M for EE was 1.06 (90% confidence interval (CI): 0.964 – 1.16), indicating average daily delivery similar to oral administration of 0.019 – 0.023 mg EE. For unbound GSD, average daily exposure was lower for treatment P vs. treatment M. The mean AUC ratio of treatment P vs. treatment M for unbound GSD was 0.820 (90% CI: 0.760 – 0.885), indicating average daily delivery from the patch of 0.057 – 0.066 mg GSD. Prolonged patch wearing did not result in a distinct decline in GSD and EE serum concentrations. In study 2, AUC at steady state (AUC0–168,ss), average steady-state serum concentration, and maximum steady-state serum concentration for EE was 2.0 – 2.7-fold higher for the EE/NGMN patch vs. the EE/GSD patch. The EE/GSD patch was well tolerated in both studies. Conclusions: Based on the 90% CI of the AUC ratio of oral treatment vs. patch application for unbound GSD and EE, the daily doses of GSD and EE released from the EE/GSD patch over the 7-day application period provided the same systemic exposure as those recorded after daily oral administration of a COC containing 0.02 mg EE and 0.06 mg GSD. The EE/GSD patch showed reduced EE exposure compared with the EE/NGMN patch. Together with its good tolerability, these properties support the EE/GSD patch as an effective and well-tolerated alternative to available transdermal and oral contraceptives. PMID:25295716

Optimal foraging on the roof of the world: Himalayan langurs and the classical prey model

PubMed Central

Sayers, Ken; Norconk, Marilyn A.; Conklin-Brittain, Nancy L.

2009-01-01

Optimal foraging theory has only been sporadically applied to nonhuman primates. The classical prey model, modified for patch choice, predicts a sliding “profitability threshold” for dropping patch types from the diet, preference for profitable foods, dietary niche breadth reduction as encounter rates increase, and that exploitation of a patch type is unrelated to its own abundance. We present results from a one-year study testing these predictions with Himalayan langurs (Semnopithecus entellus) at Langtang National Park, Nepal. Behavioral data included continuous recording of feeding bouts and between-patch travel times. Encounter rates were estimated for 55 food types, which were analyzed for crude protein, lipid, free simple sugar, and fibers. Patch types were entered into the prey model algorithm for eight seasonal time periods and differing age-sex classes and nutritional currencies. Although the model consistently underestimated diet breadth, the majority of non-predicted patch types represented rare foods. Profitability was positively related to annual/seasonal dietary contribution by organic matter estimates, while time estimates provided weaker relationships. Patch types utilized did not decrease with increasing encounter rates involving profitable foods, although low-ranking foods available year-round were taken predominantly when high-ranking foods were scarce. High-ranking foods were taken in close relation to encounter rates, while low-ranking foods were not. The utilization of an energetic currency generally resulted in closest conformation to model predictions, and it performed best when assumptions were most closely approximated. These results suggest that even simple models from foraging theory can provide a useful framework for the study of primate feeding behavior. PMID:19844998

Ex-vivoand in-vitro assessment of mucoadhesive patches containing the gel-forming polysaccharide psyllium for buccal delivery of chlorhexidine base.

PubMed

Cavallari, Cristina; Brigidi, Patrizia; Fini, Adamo

2015-12-30

The aim of the present study was to evaluate the gel-forming polysaccharide psyllium in the preparation of mucoadhesive patches for the controlled release of chlorhexidine (CHX) to treat pathologies in the oral cavity, using the casting-solvent evaporation technique. A number of different film-forming semi-synthetic polymers, such as sodium carboxymethyl cellulose (SCMC) and hydroxypropylmethyl cellulose (HPMC) were evaluated for comparison. The patch formulations were characterized in terms of drug content, morphology surface, swelling and mucoadhesive properties, microbiology inhibition assay and in vitro release tests. Three ex-vivo testswere carried out using porcine mucosa: an alternative dissolution test using artificial saliva that allows contemporary measurement of dissolution and mucoadhesion, a permeation test through the mucosa and the measurement of mucoadhesion using a Nouy tensile tester, as the maximum force required for the separation of the patch from the mucosa surface. The patches were also examined for determination of the minimum inhibitory concentration in cultures of Escherichia coli and Staphylococcus aureus. All the patches incorporating psyllium were found suitable in terms of external morphology, mucoadhesion and controlled release of the drug: in the presence of psyllium the drug displays prolonged zero-order release related to slower swelling rate of the system. Copyright © 2015. Published by Elsevier B.V.

Formulation and optimization of mucoadhesive buccal patches of losartan potassium by using response surface methodology

PubMed Central

Ikram, Md.; Gilhotra, Neeraj; Gilhotra, Ritu Mehra

2015-01-01

Background: This study was undertaken with an aim to systematically design a model of factors that would yield an optimized sustained release dosage form of an anti-hypertensive agent, losartan potassium, using response surface methodology (RSM) by employing 32 full factorial design. Materials and Methods: Mucoadhesive buccal patches were prepared using different grades of hydroxypropyl methylcellulose (HPMC) (K4M and K100M) and polyvinylpyrrolidone-K30 by solvent casting method. The amount of the release retardant polymers – HPMC K4M (X1) and HPMC K100M (X2) was taken as an independent variable. The dependent variables were the burst release in 30 min (Y1), cumulative percentage release of drug after 8 h (Y2) and swelling index (Y3) of the patches. In vitro release and swelling studies were carried out and the data were fitted to kinetic equations. Results: The physicochemical, bioadhesive, and swelling properties of patches were found to vary significantly depending on the viscosity of the polymers and their combination. Patches showed an initial burst release preceding a more gradual sustained release phase following a nonfickian diffusion process. Discussion: The results indicate that suitable bioadhesive buccal patches with desired permeability could be prepared, facilitated with the RSM. PMID:26682205

The Structure Design of Piezoelectric Poly(vinylidene Fluoride) (PVDF) Polymer-Based Sensor Patch for the Respiration Monitoring under Dynamic Walking Conditions.

PubMed

Lei, Kin-Fong; Hsieh, Yi-Zheng; Chiu, Yi-Yuan; Wu, Min-Hsien

2015-07-31

This study reports a piezoelectric poly(vinylidene fluoride) (PVDF) polymer-based sensor patch for respiration detections in dynamic walking condition. The working mechanism of respiration signal generation is based on the periodical deformations on a human chest wall during the respiratory movements, which in turn mechanically stretch the piezoelectric PVDF film to generate the corresponding electrical signals. In this study, the PVDF sensing film was completely encapsulated within the sensor patch forming a mass-spring-damper mechanical system to prevent the noises generated in a dynamic condition. To verify the design of sensor patch to prevent dynamic noises, experimental investigations were carried out. Results demonstrated the respiration signals generated and the respiratory rates measured by the proposed sensor patch were in line with the same measurements based on a commercial respiratory effort transducer both in a static (e.g., sitting) or dynamic (e.g., walking) condition. As a whole, this study has developed a PVDF-based sensor patch which is capable of monitoring respirations in a dynamic walking condition with high fidelity. Other distinctive features include its small size, light weight, ease of use, low cost, and portability. All these make it a promising sensing device to monitor respirations particularly in home care units.

Generic patches containing fentanyl: In vitro equivalence and abuse deterrent evaluation according to EMA and FDA guidelines.

PubMed

Padula, Cristina; Pescina, Silvia; Nicoli, Sara; Santi, Patrizia

2018-02-15

The aim of this work was to characterize in vitro and ex vivo the performances of Durogesic and of two bioequivalent generic products, by evaluating: (a) fentanyl release; (b) fentanyl permeation across porcine skin and (c) fentanyl ease of extraction. Additional characteristics studied are the effect of temperature and skin integrity, applied individually or combined, to check a possible synergism. The two generic patches resulted equivalent to the originator according to the new Guideline. Nevertheless, the same data reported in a different way, i.e. considering the total amount of drug permeated from the whole patch over the application time, highlight differences among the patches. The additional tests performed showed that skin integrity does not represent a barrier for fentanyl permeation across the skin, regardless of the type and complexity of the patch. The effect of temperature resulted critical for two out of three patches, probably due to the different composition and to the different structure. The combination of skin damage and elevated temperature did not produce a synergistic effect. Fentanyl extraction was different for the different products and variable according to the conditions used. The results reported in the present work underline the influence of patch composition and complexity on fentanyl extraction, release and skin permeation, in particular in conditions that can be critical, such as elevated temperature. In particular, the effect of critical variables, such as skin integrity and temperature, should be addressed to in the development of a new or new generic patch and new discriminant tests should be developed. Copyright © 2017 Elsevier B.V. All rights reserved.

Dermal exposure to monoterpenes during wood work.

PubMed

Eriksson, Kare; Wiklund, Leif

2004-06-01

The dermal exposure to the suspected allergenic monoterpenes [small alpha]-pinene, [small beta]-pinene and [capital Delta](3)-carene was assessed with a patch sampling technique. The patch used was made of activated charcoal sandwiched between two layers of cotton cloth. Patches were fastened at 12 different spots on a sampling overall and at the front of a cap to estimate the potential exposure of the body. Fastening two patches on a cotton glove, one patch representing the dorsal side and one patch representing the palm of the hand respectively, assessed the exposure on the hands. Sampling was carried out during collecting of pine and spruce boards in sawmills and during sawing of pine wood pieces in joinery shops respectively. The potential dermal exposure of the total body was 29.0-1 890 mg h(-1) with a geometric mean (GM) of 238 mg h(-1) during sawing. During collecting the GM was estimated to 100 mg h(-1) with a range of 12.2-959 mg h(-1). The hands had a mean exposure of 9.24 mg h(-1) during sawing and 3.25 mg h(-1) during collecting respectively. The good correlation between the mass of contamination on the individual body parts and the potential body exposure indicates that sampling can be performed on one body part to give a good estimation of the potential body exposure. Monoterpenes were detected at patches fastened underneath the protective clothing indicating a contamination of the skin of the worker. The patch used may overestimate the dermal exposure.

Study on cross-reactivity to the para group.

PubMed

Picardo, M; Cannistraci, C; Cristaudo, A; De Luca, C; Santucci, B

1990-01-01

In 80 patients, positive to at least one hapten of the para group (para-phenylenediamine, diaminodiphenylmethane, benzocaine, PPD mix), patch tests were carried out with freshly prepared solutions of para-phenylenediamine (PPD) and of 3 selected aromatic compounds related structurally to PPD (para-aminophenol, ortho-aminophenol, hydroquinone). The number of positive reactions correlated with the rate of decomposition of the substances as evaluated by high-pressure liquid chromatography. PPD, which was almost decomposed after 24 h, gave the highest number of positive reactions, followed by ortho-aminophenol and by para-aminophenol, while hydroquinone, which was oxidized to the extent of 35%, did not give any reactions. To evaluate if a different rate of oxidation can modify the patch test response, in the same patients and in 10 normal volunteers, tests were carried out with PPD solutions containing the oxidizing agent silver oxide (0.1%). By this procedure a significant increase in the number of positive responses was observed. The results suggest that the rate of decomposition and therefore the amount of quinone(s) generated, might be the key to eliciting patch test responses to oxidizable aromatic haptens.

Enhancing Ultimate Compressive Strength of Notch Embedded Steel Cylinders Using Overwrap CFRP Patch

NASA Astrophysics Data System (ADS)

Kabir, Mohammad Z.; Nazari, Alireza

2012-06-01

In this study, the application of Fiber Reinforced Polymer (FRP) patch for strengthening of the damaged area in thin walled steel cylinders under compression loading was investigated. In this direction, some experimental tests were carried out on the selected notch induced specimens with unique diameter-to-thickness ratio (D/t). The obtained results were compared to the intact cylinder in order to find out the reduction effect of notch on the buckling load of cylinders. Following that, the notched specimens were treated using externally FRP by wrapping around the notched area and the stability strength of the retrofitted specimens was measured experimentally. The investigation was also carried out in numerical analysis using FEM in order to develop the proposed technique for determination of optimum FRP configurations and also better understanding of the experimental observations considering the nonlinear behavior and failure modes for composite member.

A setup for combined multiphoton laser scanning microscopic and multi-electrode patch clamp experiments on brain slices

NASA Astrophysics Data System (ADS)

Helm, P. Johannes; Reppen, Trond; Heggelund, Paul

2009-02-01

Multi Photon Laser Scanning Microscopy (MPLSM) appears today as one of the most powerful experimental tools in cellular neurophysiology, notably in studies of the functional dynamics of signal processing in single neurons. Simultaneous recording of fluorescence signals at high spatial and temporal resolution and electric signals by means of multi electrode patch clamp techniques have provided new paths for the systematic investigation of neuronal mechanisms. In particular, this approach has opened for direct studies of dendritic signal processing in neurons. We report about a setup optimized for simultaneous electrophysiological multi electrode patch clamp and multi photon laser scanning fluorescence microscopic experiments on brain slices. The microscopic system is based on a modified commercially available confocal scanning laser microscope (CLSM). From a technical and operational point of view, two developments are important: Firstly, in order to reduce the workload for the experimentalist, who in general is forced to concentrate on controlling the electrophysiological parameters during the recordings, a system of shutters has been installed together with dedicated electronic modules protecting the photo detectors against destructive light levels caused by erroneous opening or closing of microscopic light paths by the experimentalist. Secondly, the standard detection unit has been improved by installing the photomultiplier tubes (PMT) in a Peltier cooled thermal box shielding the detector from both room temperature and distortions caused by external electromagnetic fields. The electrophysiological system is based on an industrial standard multi patch clamp unit ergonomically arranged around the microscope stage. The electrophysiological and scanning processes can be time coordinated by standard trigger electronics.

Alpine glacial relict species losing out to climate change: The case of the fragmented mountain hare population (Lepus timidus) in the Alps.

PubMed

Rehnus, Maik; Bollmann, Kurt; Schmatz, Dirk R; Hackländer, Klaus; Braunisch, Veronika

2018-03-13

Alpine and Arctic species are considered to be particularly vulnerable to climate change, which is expected to cause habitat loss, fragmentation and-ultimately-extinction of cold-adapted species. However, the impact of climate change on glacial relict populations is not well understood, and specific recommendations for adaptive conservation management are lacking. We focused on the mountain hare (Lepus timidus) as a model species and modelled species distribution in combination with patch and landscape-based connectivity metrics. They were derived from graph-theory models to quantify changes in species distribution and to estimate the current and future importance of habitat patches for overall population connectivity. Models were calibrated based on 1,046 locations of species presence distributed across three biogeographic regions in the Swiss Alps and extrapolated according to two IPCC scenarios of climate change (RCP 4.5 & 8.5), each represented by three downscaled global climate models. The models predicted an average habitat loss of 35% (22%-55%) by 2100, mainly due to an increase in temperature during the reproductive season. An increase in habitat fragmentation was reflected in a 43% decrease in patch size, a 17% increase in the number of habitat patches and a 34% increase in inter-patch distance. However, the predicted changes in habitat availability and connectivity varied considerably between biogeographic regions: Whereas the greatest habitat losses with an increase in inter-patch distance were predicted at the southern and northern edges of the species' Alpine distribution, the greatest increase in patch number and decrease in patch size is expected in the central Swiss Alps. Finally, both the number of isolated habitat patches and the number of patches crucial for maintaining the habitat network increased under the different variants of climate change. Focusing conservation action on the central Swiss Alps may help mitigate the predicted effects of climate change on population connectivity. © 2018 John Wiley & Sons Ltd.

Geoacoustic Characterization of the Mud Drape at the New England Mud Patch

NASA Astrophysics Data System (ADS)

Reed, A. H.

2016-02-01

The New England Mud Patch is an extensive deposit of fine-grained sediments that extends from an area south of Cape Cod, MA to south of Montauk Point Long Island, NY out on the continental shelf in water depths of 60 to 90 meters. The mud patch has a remarkable accumulation of up to a 13 meter thick sequence of mud that overlays a transgressive surface of Pleistocene Age and then thins out on the periphery where surficial sediments convert from mud to sand and sand/gravel. The deposit likely accumulated in this region due to the coalescing of shelf currents that had oppositional flow. This work focuses on a section of the mud patch that is centered over the thickest portion of mud and extends east-west for 30 km and north south for 10 km. Gravity cores were collected throughout this region and the cores penetrated the upper 2-4 m of mud at 28 different sites with multiple cores collected in several locations. The mud thickness in these regions exceeded the core barrel length, therefore the cores did not penetrate into the basal sand sediment layer, a relict transgressional horizon, which displays prominently in the acoustic data for this selected region. These cores were evaluated for compressional sound speed (averaging 1480 m/s) and density (1580 kg/m3) and found to be largely homogeneous and similar throughout the study area. The largest source of inhomogeneity was due to dispersed shell hash and disarticulated bivalves, but these inclusions represent minor components in the total sediment volume. The overlying sediment that characterizes the New England Mud Patch can be readily classified as mud, silty mud, or sandy-silty mud. This fine-grained sediment deposit reflects upon the low-energy nature of the hydrodynamics within this region.

Formulation and evaluation of buccal patches for delivery of atenolol.

PubMed

Adhikari, Surya N Ratha; Nayak, Bhabani S; Nayak, Amit K; Mohanty, Biswaranjan

2010-09-01

Buccal patches for the delivery of atenolol using sodium alginate with various hydrophilic polymers like carbopol 934 P, sodium carboxymethyl cellulose, and hydroxypropyl methylcellulose in various proportions and combinations were fabricated by solvent casting technique. Various physicomechanical parameters like weight variation, thickness, folding endurance, drug content, moisture content, moisture absorption, and various ex vivo mucoadhesion parameters like mucoadhesive strength, force of adhesion, and bond strength were evaluated. An in vitro drug release study was designed, and it was carried out using commercial semipermeable membrane. All these fabricated patches were sustained for 24 h and obeyed first-order release kinetics. Ex vivo drug permeation study was also performed using porcine buccal mucosa, and various drug permeation parameters like flux and lag time were determined.

Inhibitory action of ICI-182,780, an estrogen receptor antagonist, on BK(Ca) channel activity in cultured endothelial cells of human coronary artery.

PubMed

Liu, Yen-Chin; Lo, Yi-Ching; Huang, Chin-Wei; Wu, Sheng-Nan

2003-11-15

ICI-182,780 is known to be a selective inhibitor of the intracellular estrogen receptors. The effect of ICI-182,780 on ion currents was studied in cultured endothelial cells of human coronary artery. In whole-cell current recordings, ICI-182,780 reversibly decreased the amplitude of K(+) outward currents. The decrease in outward current caused by ICI-182,780 could be counteracted by further application of magnolol or nordihydroguaiaretic acid, yet not by 17beta-estradiol. Under current-clamp condition, ICI-182,780 (3microM) depolarized the membrane potentials of the cells, and magnolol (10 microM) or nordihydroguaiaretic acid (10 microM) reversed ICI-182,780-induced depolarization. In inside-out patches, ICI-182,780 added to the bath did not alter single-channel conductance of large-conductance Ca(2+)-activated K(+) channels (BK(Ca) channels), but decreased their open probability. ICI-182,780 reduced channel activity in a concentration-dependent manner with an IC(50) value of 3 microM. After BK(Ca) channel activity was suppressed by 2-methoxyestradiol (3 microM), subsequent application of ICI-182,780 (3 microM) did not further reduce the channel activity. The application of ICI-182,780 shifted the activation curve of BK(Ca) channels to positive potentials. Its decrease in the open probability primarily involved a reduction in channel open duration. ICI-182,780 also suppressed the proliferation of these endothelial cells with an IC(50) value of 2 microM. However, in coronary smooth muscle cells, a bell-shaped concentration-response curve for the ICI-182,780 effect on BK(Ca) channel activity was observed. This study provides evidence that ICI-182,780 can inhibit BK(Ca) channels in vascular endothelial cells in a mechanism unlikely to be linked to its anti-estrogen activity. The inhibitory effects on these channels may partly contribute to the underlying mechanisms by which ICI-182,780 affects endothelial function.

Inherited macular degeneration-associated mutations in CNGB3 increase the ligand sensitivity and spontaneous open probability of cone cyclic nucleotide-gated channels

PubMed Central

Meighan, Peter C.; Peng, Changhong; Varnum, Michael D.

2015-01-01

Cyclic nucleotide gated (CNG) channels are a critical component of the visual transduction cascade in the vertebrate retina. Mutations in the genes encoding these channels have been associated with a spectrum of inherited retinal disorders. To gain insight into their pathophysiological mechanisms, we have investigated the functional consequences of several CNGB3 mutations, previously associated with macular degeneration (Y469D and L595F) or complete achromatopsia (S156F, P309L, and G558C), by expressing these subunits in combination with wild-type CNGA3 in Xenopus oocytes and characterizing them using patch-clamp recordings in the inside-out configuration. These mutations did not prevent the formation of functional heteromeric channels, as indicated by sensitivity to block by L-cis-diltiazem. With the exception of S156F, each of the mutant channels displayed electrophysiological properties reflecting enhanced channel activity at physiological concentrations of cGMP (i.e., a gain-of-function phenotype). The increased channel activity produced by these mutations resulted from either increased functional expression levels, or increased sensitivity to cyclic nucleotides. Furthermore, L595F increased the spontaneous open probability in the absence of activating ligand, signifying a ligand independent gain-of-function change. In addition to the CNGB3 disease-associate mutations, we characterized the effects of several common CNGB3 and CNGA3 single-nucleotide polymorphisms (SNPs) on heteromeric CNGA3+CNGB3 channel function. Two of the SNPs examined (A3-T153M, and B3-W234C) produced decreased ligand sensitivity for heteromeric CNG channels. These changes may contribute to background disease susceptibility when combined with other genetic or non-genetic factors. Together, these studies help to define the underlying molecular phenotype for mutations relating to CNG channel disease pathogenesis. PMID:26106334

Modafinil inhibits K(Ca)3.1 currents and muscle contraction via a cAMP-dependent mechanism.

PubMed

Choi, Shinkyu; Kim, Moon Young; Joo, Ka Young; Park, Seonghee; Kim, Ji Aee; Jung, Jae-Chul; Oh, Seikwan; Suh, Suk Hyo

2012-07-01

Modafinil has been used as a psychostimulant for the treatment of narcolepsy. However, its primary mechanism of action remains elusive. Therefore, we examined the effects of modafinil on K(Ca)3.1 channels and vascular smooth muscle contraction. K(Ca)3.1 currents and channel activity were measured using a voltage-clamp technique and inside-out patches in mouse embryonic fibroblast cell line, NIH-3T3 fibroblasts. Intracellular adenosine 3',5'-cyclic monophosphate (cAMP) concentration was measured, and the phosphorylation of K(Ca)3.1 channel protein was examined using western blotting in NIH-3T3 fibroblasts and/or primary cultured mouse aortic smooth muscle cells (SMCs). Muscle contractions were recorded from mouse aorta and rat pulmonary artery by using a myograph developed in-house. Modafinil was found to inhibit K(Ca)3.1 currents in a concentration-dependent manner, and the half-maximal inhibition (IC(50)) of modafinil for the current inhibition was 6.8 ± 0.7 nM. The protein kinase A (PKA) activator forskolin also inhibited K(Ca)3.1 currents. The inhibitory effects of modafinil and forskolin on K(Ca)3.1 currents were blocked by the PKA inhibitors PKI(14-22) or H-89. In addition, modafinil relaxed blood vessels (mouse aorta and rat pulmonary artery) in a concentration-dependent manner. Modafinil increased cAMP concentrations in NIH-3T3 fibroblasts or primary cultured mouse aortic SMCs and phosphorylated K(Ca)3.1 channel protein in NIH-3T3 fibroblasts. However, open probability and single-channel current amplitudes of K(Ca)3.1 channels were not changed by modafinil. From these results, we conclude that modafinil inhibits K(Ca)3.1 channels and vascular smooth muscle contraction by cAMP-dependent phosphorylation, suggesting that modafinil can be used as a cAMP-dependent K(Ca)3.1 channel blocker and vasodilator. Copyright © 2012 Elsevier Ltd. All rights reserved.

The sodium-activated potassium channel Slack is modulated by hypercapnia and acidosis.

PubMed

Ruffin, V A; Gu, X Q; Zhou, D; Douglas, R M; Sun, X; Trouth, C O; Haddad, G G

2008-01-24

Slack (Slo 2.2), a member of the Slo potassium channel family, is activated by both voltage and cytosolic factors, such as Na(+) ([Na(+)](i)) and Cl(-) ([Cl(-)](i)). Since the Slo family is known to play a role in hypoxia, and since hypoxia/ischemia is associated with an increase in H(+) and CO(2) intracellularly, we hypothesized that the Slack channel may be affected by changes in intracellular concentrations of CO(2) and H(+). To examine this, we expressed the Slack channel in Xenopus oocytes and the Slo 2.2 protein was allowed to be inserted into the plasma membrane. Inside-out patch recordings were performed to examine the response of Slack to different CO(2) concentrations (0.038%, 5%, 12%) and to different pH levels (6.3, 6.8, 7.3, 7.8, 8.3). In the presence of low [Na(+)](i) (5 mM), the Slack channel open probability decreased when exposed to decreased pH or increased CO(2) in a dose-dependent fashion (from 0.28+/-0.03, n=3, at pH 7.3 to 0.006+/-0.005, n=3, P=0.0004, at pH 6.8; and from 0.65+/-0.17, n=3, at 0.038% CO(2) to 0.22+/-0.07, n=3, P=0.04 at 12% CO(2)). In the presence of high [Na(+)](i) (45 mM), Slack open probability increased (from 0.03+/-0.01 at 5 mM [Na(+)](i), n=3, to 0.11+/-0.01, n=3, P=0.01) even in the presence of decreased pH (6.3). Since Slack activity increases significantly when exposed to increased [Na(+)](i), even in presence of increased H(+), we propose that Slack may play an important role in pathological conditions during which there is an increase in the intracellular concentrations of both acid and Na(+), such as in ischemia/hypoxia.

QPatch: the past, present and future of automated patch clamp.

PubMed

Mathes, Chris

2006-04-01

The QPatch 16 significantly increases throughput for gigaseal patch clamp experiments, making direct measurements in ion channel drug discovery and safety testing feasible. Released to the market in the Autumn of 2004 by Sophion Bioscience, the QPatch originated from work done at NeuroSearch (Denmark) in the early days of automated patch clamp. Today, the QPatch provides many unique features. For example, only the QPatch includes an automated cell preparation station making several hours of unattended operation possible. The 16-channel electrode array, called the QPlate, includes glass-coated microfluidic channels for less compound absorption and, hence, more accurate IC(50) values. The microfluidic pathways also allow for very small amounts of compound used for each experiment ( approximately 5 microl per addition). Only the QPatch has four independent pipetting heads for more efficient liquid handling (especially for ligand-gated ion channel experiments). Patch clamp recordings with the QPatch match the high quality of conventional patch clamp and in some cases the results are even better. For example, only the QPatch includes 100% series resistance compensation for the elimination of false positives due to voltage errors. Finally, the modular QPatch 16 was designed with more channels in mind. The upgrade pathway to 48-channels (the QPatch HT) will be discussed.

Combined effects of VX-770 and VX-809 on several functional abnormalities of F508del-CFTR channels.

PubMed

Kopeikin, Z; Yuksek, Z; Yang, H-Y; Bompadre, S G

2014-09-01

The most common cystic fibrosis-associated mutation, the deletion of phenylalanine 508 (F508del), results in channels with poor membrane expression and impaired function. VX-770, a clinically approved drug for treatment of CF patients carrying the G551D mutation, and VX-809, a corrector shown in vitro to increase membrane expression of mutant channels, are currently undergoing clinical trials, but functional data at the molecular level is still lacking. The effect of VX-770 and VX-809 on the multiple functional defects of F508del-CFTR was assessed via excised inside-out patch-clamp experiments. VX-770 completely restores the low opening-rate of F508del-CFTR, with smaller open-time increase, in temperature-corrected and VX-809-treated channels. The shorter locked-open time of hydrolysis-deficient F508del-CFTR is also prolonged by VX-770. VX-809 does not improve channel function by itself as previously reported. The results from these studies can be interpreted as an equilibrium shift toward the open-channel conformation of F508del-CFTR channels. Copyright © 2014 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

Structural determinants of PIP(2) regulation of inward rectifier K(ATP) channels.

PubMed

Shyng, S L; Cukras, C A; Harwood, J; Nichols, C G

2000-11-01

Phosphatidylinositol 4,5-bisphosphate (PIP(2)) activates K(ATP) and other inward rectifier (Kir) channels. To determine residues important for PIP(2) regulation, we have systematically mutated each positive charge in the COOH terminus of Kir6.2 to alanine. The effects of these mutations on channel function were examined using (86)Rb efflux assays on intact cells and inside-out patch-clamp methods. Both methods identify essentially the same basic residues in two narrow regions (176-222 and 301-314) in the COOH terminus that are important for the maintenance of channel function and interaction with PIP(2). Only one residue (R201A) simultaneously affected ATP and PIP(2) sensitivity, which is consistent with the notion that these ligands, while functionally competitive, are unlikely to bind to identical sites. Strikingly, none of 13 basic residues in the terminal portion (residues 315-390) of the COOH terminus affected channel function when neutralized. The data help to define the structural requirements for PIP(2) sensitivity of K(ATP) channels. Moreover, the regions and residues defined in this study parallel those uncovered in recent studies of PIP(2) sensitivity in other inward rectifier channels, indicating a common structural basis for PIP(2) regulation.

Cryptanalysis and security improvements of 'two-factor user authentication in wireless sensor networks'.

PubMed

Khan, Muhammad Khurram; Alghathbar, Khaled

2010-01-01

User authentication in wireless sensor networks (WSN) is a critical security issue due to their unattended and hostile deployment in the field. Since sensor nodes are equipped with limited computing power, storage, and communication modules; authenticating remote users in such resource-constrained environments is a paramount security concern. Recently, M.L. Das proposed a two-factor user authentication scheme in WSNs and claimed that his scheme is secure against different kinds of attack. However, in this paper, we show that the M.L. Das-scheme has some critical security pitfalls and cannot be recommended for real applications. We point out that in his scheme: users cannot change/update their passwords, it does not provide mutual authentication between gateway node and sensor node, and is vulnerable to gateway node bypassing attack and privileged-insider attack. To overcome the inherent security weaknesses of the M.L. Das-scheme, we propose improvements and security patches that attempt to fix the susceptibilities of his scheme. The proposed security improvements can be incorporated in the M.L. Das-scheme for achieving a more secure and robust two-factor user authentication in WSNs.

Concentrations and stability of methyl methacrylate, glutaraldehyde, formaldehyde and nickel sulfate in commercial patch test allergen preparations.

PubMed

Siegel, Paul D; Fowler, Joseph F; Law, Brandon F; Warshaw, Erin M; Taylor, James S

2014-05-01

Epicutaneous patch tests are used to reproduce allergy and diagnose allergic contact dermatitis. Reliable allergen test preparations are required. The purpose of the present study was to measure the actual concentrations of nickel(II) sulfate hexahydrate (NiSO4 ), methyl methacrylate, formaldehyde, and glutaraldehyde, and to compare them with the labelled concentrations, in commercial patch test allergen preparations found in dermatology clinics where patch testing is routinely performed. The commercial in-date and out-of-date patch test allergen preparations concentrations of NiSO4 , methyl methacrylate, formaldehyde and glutaraldehyde from one to three participating clinics were analysed with chromatographic or wet chemical techniques. NiSO4 and formaldehyde concentrations were at or above the labelled concentrations; however, formaldehyde loss occurred with storage. NiSO4 particulate was uniformly distributed throughout the petrolatum. 'In-use' methyl methacrylate reagent syringes all contained ≤ 56% of the 2% label concentration, with no observable relationship with expiration date. Lower methyl methacrylate cocentrations were consistently measured at the syringe tip end, suggesting loss resulting from methyl methacrylate's volatility. The concentrations of glutaraldehyde patch test allergen preparations ranged from 27% to 45% of the labelled (1% in pet.) concentration, independently of expiration date. Some false-negative methyl methacrylate, formaldehyde or glutaraldehyde patch test results may be attributable to instability of the test preparations. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Perforator-based island flap with a peripheral muscle patch for coverage of sacral sores.

PubMed

Chang, Jung Woo; Lee, Jang Hyun; Choi, Matthew Seung Suk

2016-06-01

Despite numerous therapeutic advances, the treatment of pressure sores remains a challenge. The increased use of perforator flaps enables surgeons to minimize donor-site morbidity by sparing the underlying muscle. In the presence of focal deep spaces, however, the inclusion of muscle would be beneficial. The goal of this study was to introduce a method for including a muscle patch at the periphery of a perforator-based island flap for coverage of sacral pressure sores. Between March 2010 and February 2015, 26 patients with stage IV sacral sores underwent perforator-based island flap reconstruction with a peripheral muscle patch. Patient characteristics, including sex, age, defect size, and postoperative complications, were recorded. All flaps survived without major complications. No flap necrosis was noted. The present study shows that a muscle patch incorporated into the periphery of a perforator-based flap can be transferred safely. This can be a good surgical option in cases where infection control or more volume is needed. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Speeding up 3D speckle tracking using PatchMatch

NASA Astrophysics Data System (ADS)

Zontak, Maria; O'Donnell, Matthew

2016-03-01

Echocardiography provides valuable information to diagnose heart dysfunction. A typical exam records several minutes of real-time cardiac images. To enable complete analysis of 3D cardiac strains, 4-D (3-D+t) echocardiography is used. This results in a huge dataset and requires effective automated analysis. Ultrasound speckle tracking is an effective method for tissue motion analysis. It involves correlation of a 3D kernel (block) around a voxel with kernels in later frames. The search region is usually confined to a local neighborhood, due to biomechanical and computational constraints. For high strains and moderate frame-rates, however, this search region will remain large, leading to a considerable computational burden. Moreover, speckle decorrelation (due to high strains) leads to errors in tracking. To solve this, spatial motion coherency between adjacent voxels should be imposed, e.g., by averaging their correlation functions.1 This requires storing correlation functions for neighboring voxels, thus increasing memory demands. In this work, we propose an efficient search using PatchMatch, 2 a powerful method to find correspondences between images. Here we adopt PatchMatch for 3D volumes and radio-frequency signals. As opposed to an exact search, PatchMatch performs random sampling of the search region and propagates successive matches among neighboring voxels. We show that: 1) Inherently smooth offset propagation in PatchMatch contributes to spatial motion coherence without any additional processing or memory demand. 2) For typical scenarios, PatchMatch is at least 20 times faster than the exact search, while maintaining comparable tracking accuracy.

Risk factors and common contact allergens in facial allergic contact dermatitis patients.

PubMed

Kasemsarn, Pranee; Iamphonrat, Thanawan; Boonchai, Waranya

2016-04-01

Facial dermatitis is commonly encountered in dermatologic practice. It is sometimes difficult to manage because its causative factors may be multiple and difficult to diagnose. This study was designed to identify the characteristics, patch test results, and final diagnoses of facial dermatitis patients who were referred to a contact dermatitis clinic and to identify factors associated with facial allergic contact dermatitis (ACD). We retrospectively reviewed case records of facial dermatitis patients who underwent patch testing at the clinic during the period from July 2006 to June 2011. Of the 891 patients patch-tested, 244 (27.4%) had facial dermatitis. Female patients were 9.1 times more predominant than male patients. The mean ± standard deviation age of patients was 37.3 ± 14.8 years. A total of 199 (81.6%) patients demonstrated at least one positive reaction to a patch test, 66.7% of which were clinically relevant. Allergic contact dermatitis was diagnosed in 45.5% of patients. Independent factors predisposing towards facial dermatitis were female sex, having a previous history of cosmetic allergy, a positive patch test reaction to hairdressing product-related allergens, and a positive allergic reaction to preservative allergens. The prevalence of facial dermatitis was 27.4%. Almost half of all patients with facial dermatitis demonstrated ACD. Factors associated with facial ACD were female gender, a history of cosmetic allergy, and positive patch test reactions to hairdressing product-related allergens and preservatives. © 2015 The International Society of Dermatology.

Comparison of estrus synchronization by controlled internal drug release device (CIDR) and adhesive transdermal progestin patch in postpartum beef cows.

PubMed

Kajaysri, Jatuporn; Chumchoung, Chaiwat; Wutthiwitthayaphong, Supphathat; Suthikrai, Wanvipa; Sangkamanee, Praphai

2017-09-15

Estrous synchronization with progesterone based protocols has been essentially used in cattle industry. Although intravaginal devices have been commonly used, this technique may induce vaginitis. This study aimed at examining the efficiency of novel transdermal progestin patch on follicle development and comparing the progestin patch versus CIDR device on estrous synchronization, complication at treated site and pregnancy in beef cattle. In experiment 1, seven beef cows were treated with an adhesive transdermal progestin patch on the ventral surface of the proximal part of the tail for 7 days. The cows were daily examined the follicular development using ultrasonography starting on Day 0 till 3 days after hormone removal. Experiment 2, forty beef cows were divided into two equal groups (20 cows per group). The cows randomly allocated to received either vaginal insertion of CIDR (n = 20) or treated with an adhesive transdermal progestin patch (n = 20). The levels of plasma progesterone during the experiment and the numbers of standing estrous cows were recorded. Timed artificial inseminated (TAI) was performed at 60 h after CIDR or patch termination. Pregnancy rates were determined at 60 days after TAI. Experiment 1 revealed that the novel transdermal progestin patch could efficiently control follicular growth. All the seven treated cows had dominant follicle upon dermal patch removal indicating the effectiveness of the progestin patch. In experiment 2, the percentages of cows exhibited standing estrus were similar between transdermal patch (72.22%) and CIDR (70.00%). The levels of plasma progesterone during CIDR treatment were significantly higher (4.06 ± 1.65 ng/mL on Day 1 and 3.62 ± 1.60 ng/mL on Day 7) compared with transdermal patch (2.60 ± 1.43 ng/mL on Day 1 and 1.81 ± 1.57 ng/mL on Day 7). Three cows treated with CIDR (15%) developed vaginitis while none of cows had physically dermal reaction at adhesive site. Cows synchronized with these two protocols had similar pregnancy rates (50.00%) following fixed time artificial insemination. It is concluded that transdermal progestin patch was equally effective in estrus synchronization as compared with traditional CIDR. However, the transdermal patch demonstrated less complication. This device should therefore be considered as an alternative method for estrus synchronization in postpartum beef cattle. Copyright © 2017 Elsevier Inc. All rights reserved.

Holter monitor (24h)

MedlinePlus

... please enable JavaScript. A Holter monitor is a machine that continuously records the heart’s rhythms. The monitor is worn for 24 to 48 hours during normal activity. How the Test is Performed Electrodes (small conducting patches) are stuck ...

Temporal changes in community composition of heterotrophic bacteria during in situ iron enrichment in the western subarctic Pacific (SEEDS-II)

NASA Astrophysics Data System (ADS)

Kataoka, Takafumi; Suzuki, Koji; Hayakawa, Maki; Kudo, Isao; Higashi, Seigo; Tsuda, Atsushi

2009-12-01

Little is known about the effects of iron enrichment in high-nitrate low-chlorophyll (HNLC) waters on the community composition of heterotrophic bacteria, which are crucial to nutrient recycling and microbial food webs. Using denaturing gradient gel electrophoresis (DGGE) of 16S rDNA fragments, we investigated the heterotrophic eubacterial community composition in surface waters during an in situ iron-enrichment experiment (SEEDS-II) in the western subarctic Pacific in the summer of 2004. DGGE fingerprints representing the community composition of eubacteria differed inside and outside the iron-enriched patch. Sequencing of DGGE bands revealed that at least five phylotypes of α-proteobacteria including Roseobacter, Cytophaga-Flavobacteria- Bacteroides (CFB), γ-proteobacteria, and Actinobacteria occurred in almost all samples from the iron-enriched patch. Diatoms did not bloom during SEEDS-II, but the eubacterial composition in the iron-enriched patch was similar to that in diatom blooms observed previously. Although dissolved organic carbon (DOC) accumulation was not detected in surface waters during SEEDS-II, growth of the Roseobacter clade might have been particularly stimulated after iron additions. Two identified phylotypes of CFB were closely related to the genus Saprospira, whose algicidal activity might degrade the phytoplankton assemblages increased by iron enrichment. These results suggest that the responses of heterotrophic bacteria to iron enrichment could differ among phylotypes during SEEDS-II.

An exotic invasive plant selects for increased competitive tolerance, but not competitive suppression, in a native grass.

PubMed

Fletcher, Rebecca A; Callaway, Ragan M; Atwater, Daniel Z

2016-06-01

Exotic invasive plants can exert strong selective pressure for increased competitive ability in native plants. There are two fundamental components of competitive ability: suppression and tolerance, and the current paradigm that these components have equal influences on a species' overall competitive ability has been recently questioned. If these components do not have equal influences on overall ability, then selection on competitive tolerance and suppression may be disproportionate. We used naturally invaded communities to study the effects of selection caused by an invasive forb, Centaurea stoebe, on a native grass, Pseudoroegneria spicata. P. spicata plants were harvested from within dense C. stoebe patches and from nearby uninvaded areas, divided clonally into replicates, then transplanted into a common garden where they grew alone or competed with C. stoebe. We found that P. spicata plants collected from within C. stoebe patches were significantly more tolerant of competition with C. stoebe than P. spicata plants collected from uninvaded areas, but plants from inside invaded patches were not superior at suppressing C. stoebe. These results are consistent with the hypothesis that strong competitors may select for tolerance to competition more than for the ability to suppress neighbors. This has important implications for how native plant communities may respond to invasion over time, and how invasive and native species may ultimately coexist.

The inside-out trans-obturator sling: a novel surgical technique for the treatment of male urinary incontinence.

PubMed

de Leval, Jean; Waltregny, David

2008-11-01

To describe a new sling procedure for treating stress urinary incontinence (SUI) after radical prostatectomy (RP) and prospectively evaluate its short-term safety and efficacy. The sling technique uses specific instruments and a polypropylene mesh with two arms that are passed inside to outside through the obturator foramens, pulled for compressing the bulbar urethra upward, and tied to each other across the midline. Patients with detrusor overactivity were excluded. Baseline and follow-up evaluations included uroflowmetry and continence and quality of life (QoL) questionnaires. Cure was defined by no pad use and improvement by a number of pads/d 5pads/d, respectively. The procedure was preceded by an endoscopic urethrotomy in four patients. No perioperative complication was noted; three patients required suprapubic catheterization. At 6 mo, nine (45%) patients were cured and eight others (40%) were improved (1pad/d). QoL was significantly enhanced and 80% of patients were moderately to completely satisfied with the procedure. Preoperative and postoperative maximum flow rate and postvoid residual values were not statistically different. No sling infection, urethra erosion, persistent pain, or neurologic complications were observed. The inside-out trans-obturator sling procedure appears to be safe and efficient at short term. Further studies are warranted to determine long-term outcome.

Patch-clamp recordings of rat neurons from acute brain slices of the somatosensory cortex during magnetic stimulation

PubMed Central

Pashut, Tamar; Magidov, Dafna; Ben-Porat, Hana; Wolfus, Shuki; Friedman, Alex; Perel, Eli; Lavidor, Michal; Bar-Gad, Izhar; Yeshurun, Yosef; Korngreen, Alon

2014-01-01

Although transcranial magnetic stimulation (TMS) is a popular tool for both basic research and clinical applications, its actions on nerve cells are only partially understood. We have previously predicted, using compartmental modeling, that magnetic stimulation of central nervous system neurons depolarized the soma followed by initiation of an action potential in the initial segment of the axon. The simulations also predict that neurons with low current threshold are more susceptible to magnetic stimulation. Here we tested these theoretical predictions by combining in vitro patch-clamp recordings from rat brain slices with magnetic stimulation and compartmental modeling. In agreement with the modeling, our recordings demonstrate the dependence of magnetic stimulation-triggered action potentials on the type and state of the neuron and its orientation within the magnetic field. Our results suggest that the observed effects of TMS are deeply rooted in the biophysical properties of single neurons in the central nervous system and provide a framework both for interpreting existing TMS data and developing new simulation-based tools and therapies. PMID:24917788

Comparison between various patch wise strategies for reconstruction of ultra-spectral cubes captured with a compressive sensing system

NASA Astrophysics Data System (ADS)

Oiknine, Yaniv; August, Isaac Y.; Revah, Liat; Stern, Adrian

2016-05-01

Recently we introduced a Compressive Sensing Miniature Ultra-Spectral Imaging (CS-MUSI) system. The system is based on a single Liquid Crystal (LC) cell and a parallel sensor array where the liquid crystal cell performs spectral encoding. Within the framework of compressive sensing, the CS-MUSI system is able to reconstruct ultra-spectral cubes captured with only an amount of ~10% samples compared to a conventional system. Despite the compression, the technique is extremely complex computationally, because reconstruction of ultra-spectral images requires processing huge data cubes of Gigavoxel size. Fortunately, the computational effort can be alleviated by using separable operation. An additional way to reduce the reconstruction effort is to perform the reconstructions on patches. In this work, we consider processing on various patch shapes. We present an experimental comparison between various patch shapes chosen to process the ultra-spectral data captured with CS-MUSI system. The patches may be one dimensional (1D) for which the reconstruction is carried out spatially pixel-wise, or two dimensional (2D) - working on spatial rows/columns of the ultra-spectral cube, as well as three dimensional (3D).

Classification of breast cancer cytological specimen using convolutional neural network

NASA Astrophysics Data System (ADS)

Żejmo, Michał; Kowal, Marek; Korbicz, Józef; Monczak, Roman

2017-01-01

The paper presents a deep learning approach for automatic classification of breast tumors based on fine needle cytology. The main aim of the system is to distinguish benign from malignant cases based on microscopic images. Experiment was carried out on cytological samples derived from 50 patients (25 benign cases + 25 malignant cases) diagnosed in Regional Hospital in Zielona Góra. To classify microscopic images, we used convolutional neural networks (CNN) of two types: GoogLeNet and AlexNet. Due to the very large size of images of cytological specimen (on average 200000 × 100000 pixels), they were divided into smaller patches of size 256 × 256 pixels. Breast cancer classification usually is based on morphometric features of nuclei. Therefore, training and validation patches were selected using Support Vector Machine (SVM) so that suitable amount of cell material was depicted. Neural classifiers were tuned using GPU accelerated implementation of gradient descent algorithm. Training error was defined as a cross-entropy classification loss. Classification accuracy was defined as the percentage ratio of successfully classified validation patches to the total number of validation patches. The best accuracy rate of 83% was obtained by GoogLeNet model. We observed that more misclassified patches belong to malignant cases.

Investigation of TM Band-to-band Registration Using the JSC Registration Processor

NASA Technical Reports Server (NTRS)

Yao, S. S.; Amis, M. L.

1984-01-01

The JSC registration processor performs scene-to-scene (or band-to-band) correlation based on edge images. The edge images are derived from a percentage of the edge pixels calculated from the raw scene data, excluding clouds and other extraneous data in the scene. Correlations are performed on patches (blocks) of the edge images, and the correlation peak location in each patch is estimated iteratively to fractional pixel location accuracy. Peak offset locations from all patches over the scene are then considered together, and a variety of tests are made to weed out outliers and other inconsistencies before a distortion model is assumed. Thus, the correlation peak offset locations in each patch indicate quantitatively how well the two TM bands register to each other over that patch of scene data. The average of these offsets indicate the overall accuracies of the band-to-band registration. The registration processor was also used to register one acquisition to another acquisition of multitemporal TM data acquired over the same ground track. Band 4 images from both acquisitions were correlated and an rms error of a fraction of a pixel was routinely obtained.

DeepIED: An epileptic discharge detector for EEG-fMRI based on deep learning.

PubMed

Hao, Yongfu; Khoo, Hui Ming; von Ellenrieder, Nicolas; Zazubovits, Natalja; Gotman, Jean

2018-01-01

Presurgical evaluation that can precisely delineate the epileptogenic zone (EZ) is one important step for successful surgical resection treatment of refractory epilepsy patients. The noninvasive EEG-fMRI recording technique combined with general linear model (GLM) analysis is considered an important tool for estimating the EZ. However, the manual marking of interictal epileptic discharges (IEDs) needed in this analysis is challenging and time-consuming because the quality of the EEG recorded inside the scanner is greatly deteriorated compared to the usual EEG obtained outside the scanner. This is one of main impediments to the widespread use of EEG-fMRI in epilepsy. We propose a deep learning based semi-automatic IED detector that can find the candidate IEDs in the EEG recorded inside the scanner which resemble sample IEDs marked in the EEG recorded outside the scanner. The manual marking burden is greatly reduced as the expert need only edit candidate IEDs. The model is trained on data from 30 patients. Validation of IEDs detection accuracy on another 37 consecutive patients shows our method can improve the median sensitivity from 50.0% for the previously proposed template-based method to 84.2%, with false positive rate as 5 events/min. Reproducibility validation on 15 patients is applied to evaluate if our method can produce similar hemodynamic response maps compared with the manual marking ground truth results. We explore the concordance between the maximum hemodynamic response and the intracerebral EEG defined EZ and find that both methods produce similar percentage of concordance (76.9%, 10 out of 13 patients, electrode was absent in the maximum hemodynamic response in two patients). This tool will make EEG-fMRI analysis more practical for clinical usage.

[Occlusion treatment for amblyopia. Age dependence and dose-response relationship].

PubMed

Fronius, M

2016-04-01

Based on clinical experience and studies on animal models the age of 6-7 years was regarded as the limit for treatment of amblyopia, although functional improvement was also occasionally reported in older patients. New technical developments as well as insights from clinical studies and the neurosciences have attracted considerable attention to this topic. Various aspects of the age dependence of amblyopia treatment are discussed in this article, e. g. prescription, electronic monitoring of occlusion dosage, calculation of indicators for age-dependent plasticity of the visual system, and novel, alternative treatment approaches. Besides a discussion of the recent literature, results of studies by our "Child Vision Research Unit" in Frankfurt are presented: results of a questionnaire about prescription habits concerning age limits of patching, electronic recording of occlusion in patients beyond the conventional treatment age, calculation of dose-response function and efficiency of patching and their age dependence. The results of the questionnaire illustrate the uncertainty about age limits of prescription with significant deviations from the guideline of the German Ophthalmological Society (DOG). Electronic recording of occlusion allowed the quantification of declining dose-response function and treatment efficiency between 5 and 16 years of age. Reports about successful treatment with conventional and novel methods in adults are at variance with the notion of a rigid adult visual system lacking plasticity. Electronic recording of patching allowed new insights into the age-dependent susceptibility of the visual system and contributes to a more evidence-based treatment of amblyopia. Alternative approaches for adults challenge established notions about age limits of amblyopia therapy. Further studies comparing different treatment options are urgently needed.

Expanding neurochemical investigations with multi-modal recording: simultaneous fast-scan cyclic voltammetry, iontophoresis, and patch clamp measurements.

PubMed

Kirkpatrick, D C; McKinney, C J; Manis, P B; Wightman, R M

2016-08-02

Multi-modal recording describes the simultaneous collection of information across distinct domains. Compared to isolated measurements, such studies can more easily determine relationships between varieties of phenomena. This is useful for neurochemical investigations which examine cellular activity in response to changes in the local chemical environment. In this study, we demonstrate a method to perform simultaneous patch clamp measurements with fast-scan cyclic voltammetry (FSCV) using optically isolated instrumentation. A model circuit simulating concurrent measurements was used to predict the electrical interference between instruments. No significant impact was anticipated between methods, and predictions were largely confirmed experimentally. One exception was due to capacitive coupling of the FSCV potential waveform into the patch clamp amplifier. However, capacitive transients measured in whole-cell current clamp recordings were well below the level of biological signals, which allowed the activity of cells to be easily determined. Next, the activity of medium spiny neurons (MSNs) was examined in the presence of an FSCV electrode to determine how the exogenous potential impacted nearby cells. The activities of both resting and active MSNs were unaffected by the FSCV waveform. Additionally, application of an iontophoretic current, used to locally deliver drugs and other neurochemicals, did not affect neighboring cells. Finally, MSN activity was monitored during iontophoretic delivery of glutamate, an excitatory neurotransmitter. Membrane depolarization and cell firing were observed concurrently with chemical changes around the cell resulting from delivery. In all, we show how combined electrophysiological and electrochemical measurements can relate information between domains and increase the power of neurochemical investigations.

Assessment of phytoplankton and environmental variables for water quality and trophic state classification in the Gemlik Gulf, Marmara Sea (Turkey).

PubMed

Balci, Muharrem; Balkis, Neslihan

2017-02-15

Phytoplankton assemblages related to environmental factors and ecological status of the Gemlik Gulf were investigated between June 2010 and May 2011. A total 155 phytoplankton species were detected and 6 taxa (Amphisolenia laticincta, Archaeperidinium minutum, Cochlodinium sp., Gynogonadinium aequatoriale, Heterocapsa rotundata and Metaphalacroma sp.) were new records for the Turkish Seas. The lowest and highest total phytoplankton abundance among the sampling units (depths) was recorded in April 2011 (7.4×10 3 cellsL -1 ) and July 2010 (251.8×10 3 cellsL -1 ). Local small patches of visible red tide events were detected especially in the gulf, although a phytoplankton bloom was not observed. The water column was well stratified in the early autumn and well mixed in the early spring according to stratification index values. Surface nutrient concentrations increased especially at stations located inside of the gulf. The limiting effect of silicate was observed in early, mid-summer and early winter periods while the nitrogen was the limiting nutrient in the gulf during the whole sampling period. In the Gulf, low water quality-high mesotrophic and bad water quality-eutrophic status, high quality and low trophic level were generally detected according to Chl a, dissolved oxygen and trophic index. However, indices developed to determine the trophic level and water quality of the Mediterranean Sea can give unexpected results about the current environmental quality status when it is applied to the Marmara Sea which has limited photic zone by the halocline-pycnocline and thermocline. Copyright © 2016 Elsevier Ltd. All rights reserved.

Visual saliency detection based on modeling the spatial Gaussianity

NASA Astrophysics Data System (ADS)

Ju, Hongbin

2015-04-01

In this paper, a novel salient object detection method based on modeling the spatial anomalies is presented. The proposed framework is inspired by the biological mechanism that human eyes are sensitive to the unusual and anomalous objects among complex background. It is supposed that a natural image can be seen as a combination of some similar or dissimilar basic patches, and there is a direct relationship between its saliency and anomaly. Some patches share high degree of similarity and have a vast number of quantity. They usually make up the background of an image. On the other hand, some patches present strong rarity and specificity. We name these patches "anomalies". Generally, anomalous patch is a reflection of the edge or some special colors and textures in an image, and these pattern cannot be well "explained" by their surroundings. Human eyes show great interests in these anomalous patterns, and will automatically pick out the anomalous parts of an image as the salient regions. To better evaluate the anomaly degree of the basic patches and exploit their nonlinear statistical characteristics, a multivariate Gaussian distribution saliency evaluation model is proposed. In this way, objects with anomalous patterns usually appear as the outliers in the Gaussian distribution, and we identify these anomalous objects as salient ones. Experiments are conducted on the well-known MSRA saliency detection dataset. Compared with other recent developed visual saliency detection methods, our method suggests significant advantages.

Giga-ohm seals on intracellular membranes: a technique for studying intracellular ion channels in intact cells.

PubMed

Jonas, E A; Knox, R J; Kaczmarek, L K

1997-07-01

A method is outlined for obtaining giga-ohm seals on intracellular membranes in intact cells. The technique employs a variant of the patch-clamp technique: a concentric electrode arrangement protects an inner patch pipette during penetration of the plasma membrane, after which a seal can be formed on an internal organelle membrane. Using this technique, successful recordings can be obtained with the same frequency as with conventional patch clamping. To localize the position of the pipette within cells, lipophilic fluorescent dyes are included in the pipette solution. These dyes stain the membrane of internal organelles during seal formation and can then be visualized by video-enhanced or confocal imaging. The method can detect channels activated by inositol trisphosphate, as well as other types of intracellular membrane ion channel activity, and should facilitate studies of internal membranes in intact neurons and other cell types.

Correlated full-field and pointwise temporally resolved measurements of thermomechanical stress inside an operating power transistor

NASA Astrophysics Data System (ADS)

Borza, Dan N.; Gautrelet, Christophe

2015-01-01

The paper describes a measurement system based on time-resolved speckle interferometry, able to record long series of thermally induced full-field deformation maps of die and wire bonds inside an operating power transistor. The origin of the deformation is the transistor heating during its normal operation. The full-field results consist in completely unwrapped deformation maps for out-of-plane displacements greater than 14 μm, with nanometer resolution, in presence of discontinuities due to structural and material inhomogeneity. These measurements are synchronized with the measurement of heatsink temperature and of base-emitter junction temperature, so as to provide data related to several interacting physical parameters. The temporal histories of the displacement are also accessible for any point. They are correlated with the thermal and electrical time series. Mechanical full-field curvatures may also be estimated, making these measurements useful for inspecting physical origins of thermomechanical stresses and for interacting with numerical models used in reliability-related studies.

Indirect facilitation becomes stronger with seedling age in a degraded seasonally dry forest

NASA Astrophysics Data System (ADS)

Torres, Romina C.; Renison, Daniel

2016-01-01

In seasonally dry forests direct facilitation by woody species due to amelioration of harsh abiotic conditions could be important during germination and early establishment of tree seedlings, and under some species but not others. Recent research suggests that at later stages facilitation by woody species may be indirect due to protection of saplings from herbivores, implying that under absence of herbivores reforestation programs may plant saplings in unprotected open sites. We used the native tree Lithraea molleoides from central Argentina as a model species to test this hypothesis. We performed a seeding and planting experiment simulating early and late establishment respectively, which included 234 study plots situated in herbaceous, shrub and tree patches of differing species composition and under two herbivore treatments (grazed and ungrazed) and replicated at three sites. Seedling counts averaged 0.82% of the sown seeds after 6 months, were highest under shrubs and lowest in open patches, and were influenced by woody species composition only in tree patches (all P values < 0.05). At seedling stages we detected no influence of herbivory (P = 0.4) nor of indirect facilitation due to herbivory (herbivory × patch type P = 0.7). Survival of planted saplings was 53% after 3 years and over winter dieback affected 76% of the saplings. At sapling stages we found an increasing importance of indirect facilitation through protection from herbivores, as we recorded the highest sapling survival and growth at tree and shrub patches and the lowest in open patches (all P values < 0.001), and a negative effect of livestock (P < 0.001) mainly on the open patches (herbivory × patch type P = 0.07 and P = 0.001 for survival and growth, respectively). We found no significant influence of woody species composition on sapling survival and growth (all P values > 0.05). We conclude that direct facilitation is involved at all studied stages while indirect facilitation becomes increasingly important at the sapling stage.

P-glycoprotein substrate transport assessed by comparing cellular and vesicular ATPase activity.

PubMed

Nervi, Pierluigi; Li-Blatter, Xiaochun; Aänismaa, Päivi; Seelig, Anna

2010-03-01

We compared the P-glycoprotein ATPase activity in inside-out plasma membrane vesicles and living NIH-MDR1-G185 cells with the aim to detect substrate transport. To this purpose we used six substrates which differ significantly in their passive influx through the plasma membrane. In cells, the cytosolic membrane leaflet harboring the substrate binding site of P-glycoprotein has to be approached by passive diffusion through the lipid membrane, whereas in inside-out plasma membrane vesicles, it is accessible directly from the aqueous phase. Compounds exhibiting fast passive influx compared to active efflux by P-glycoprotein induced similar ATPase activity profiles in cells and inside-out plasma membrane vesicles, because their concentrations in the cytosolic leaflets were similar. Compounds exhibiting similar influx as efflux induced in contrast different ATPase activity profiles in cells and inside-out vesicles. Their concentration was significantly lower in the cytosolic leaflet of cells than in the cytosolic leaflet of inside-out membrane vesicles, indicating that P-glycoprotein could cope with passive influx. P-glycoprotein thus transported all compounds at a rate proportional to ATP hydrolysis (i.e. all compounds were substrates). However, it prevented substrate entry into the cytosol only if passive influx of substrates across the lipid bilayer was in a similar range as active efflux. Copyright 2009 Elsevier B.V. All rights reserved.

The role of colonization in the dynamics of patchy populations of a cyclic vole species.

PubMed

Glorvigen, Petter; Gundersen, Gry; Andreassen, Harry P; Ims, Rolf A

2013-09-01

The crash phase of vole populations with cyclic dynamics regularly leads to vast areas of uninhabited habitats. Yet although the capacity for cyclic voles to re-colonize such empty space is likely to be large and predicted to have become evolved as a distinct life history trait, the processes of colonization and its effect on the spatio-temporal dynamics have been little studied. Here we report from an experiment with root voles (Microtus oeconomus) specifically targeted at quantifying the process of colonization of empty patches from distant source patches and its resultant effect on local vole deme size variation in a patchy landscape. Three experimental factors: habitat quality, predation risk and inter-patch distance were employed among 24 habitat patches in a 100 × 300-m experimental area. The first-born cohort in the spring efficiently colonized almost all empty patches irrespective of the degree of patch isolation and predation risk, but this was dependent on habitat quality. Just after the initial colonization wave the deme sizes in patches of the same quality were underdispersed relative to Poisson variance, indicating regulated (density-dependent) settlement. Towards the end of the breeding season local demographic processes acted to smooth out the initial post-colonization differences among source and colonization patches, and among patches of initially different quality. However, at this time demographic stochasticity had also given rise to a large (overdispersed) variation in deme sizes that may have contributed to an overshadowing of the effect of other factors. The results of this experiment confirmed our expectation that the space-filling capacity of voles is large. The costs associated with transience appeared to be so low, at least at the spatial scale considered in this experiment, that such costs are not likely to substantially constrain habitat selection and colonization in the increase phase of cyclic patchy populations.

Effects of patch size and type of coffee matrix on ithomiine butterfly diversity and dispersal in cloud-forest fragments.

PubMed

Muriel, Sandra B; Kattan, Gustavo H

2009-08-01

Determining the permeability of different types of landscape matrices to animal movement is essential for conserving populations in fragmented landscapes. We evaluated the effects of habitat patch size and matrix type on diversity, isolation, and dispersal of ithomiine butterflies in forest fragments surrounded by coffee agroecosystems in the Colombian Andes. Because ithomiines prefer a shaded understory, we expected the highest diversity and abundance in large fragments surrounded by shade coffee and the lowest in small fragments surrounded by sun coffee. We also thought shade coffee would favor butterfly dispersal and immigration into forest patches. We marked 9675 butterflies of 39 species in 12 forest patches over a year. Microclimate conditions were more similar to the forest interior in the shade-coffee matrix than in the sun-coffee matrix, but patch size and matrix type did not affect species richness and abundance in forest fragments. Furthermore, age structure and temporal recruitment patterns of the butterfly community were similar in all fragments, independent of patch size or matrix type. There were no differences in the numbers of butterflies flying in the matrices at two distances from the forest patch, but their behavior differed. Flight in the sun-coffee matrix was rapid and directional, whereas butterflies in shade-coffee matrix flew slowly. Seven out of 130 recaptured butterflies immigrated into patches in the shade-coffee matrix, and one immigrated into a patch surrounded by sun coffee. Although the shade-coffee matrix facilitated movement in the landscape, sun-coffee matrix was not impermeable to butterflies. Ithomiines exhibited behavioral plasticity in habitat use and high mobility. These traits favor their persistence in heterogeneous landscapes, opening opportunities for their conservation. Understanding the dynamics and resource requirements of different organisms in rural landscapes is critical for identifying management options that address both animals' and farmers' needs.

Biotic interactions affect the colonization behavior of aquatic detritivorous macroinvertebrates in a heterogeneous environment

NASA Astrophysics Data System (ADS)

Verschut, Thomas A.; Meineri, Eric; Basset, Alberto

2015-05-01

It has previously been suggested that macroinvertebrates actively search for suitable patches to colonize. However, it is not well understood how the spatial arrangement of patches can affect colonization rates. In this study, we determined the importance of the environmental factors (distance, connectivity and resource availability) for patch colonization in an experimental system using Gammarus aequicauda (Amphipoda), Lekanesphaera hookeri (Isopoda) and Ecrobia ventrosa (Gastropoda). Furthermore, we also assessed how the relative importance of each of these environmental factors differed in interactions between the three species. The single species experiments showed that distance was the most important factor for G. aequicauda and E. ventrosa. However, while E. ventrosa preferred patches close to the release point, G. aequicauda strongly preferred patches further from the release point. High resource availability was a strong determinant for the patch colonization of G. aequicauda and L. hookeri. Connectivity was only of moderate importance in the study system for L. hookeri and E. ventrosa. The effects of the environmental factors were strongly affected by interspecific interactions in the multispecies experiments. For G. aequicauda, the distance preference was lowered in the presence of E. ventrosa. Moreover, while for L. hookeri the effect of resource availability was ruled out by the species interactions, resource availability gained importance for E. ventrosa in the presence of any of the other species. Our results suggest a strong link between environmental factors and biotic interactions in the colonization of habitat patches and indicate that the effect of biotic interactions is especially important for species sharing similar traits.

Boolean Operations with Prism Algebraic Patches

PubMed Central

Bajaj, Chandrajit; Paoluzzi, Alberto; Portuesi, Simone; Lei, Na; Zhao, Wenqi

2009-01-01

In this paper we discuss a symbolic-numeric algorithm for Boolean operations, closed in the algebra of curved polyhedra whose boundary is triangulated with algebraic patches (A-patches). This approach uses a linear polyhedron as a first approximation of both the arguments and the result. On each triangle of a boundary representation of such linear approximation, a piecewise cubic algebraic interpolant is built, using a C1-continuous prism algebraic patch (prism A-patch) that interpolates the three triangle vertices, with given normal vectors. The boundary representation only stores the vertices of the initial triangulation and their external vertex normals. In order to represent also flat and/or sharp local features, the corresponding normal-per-face and/or normal-per-edge may be also given, respectively. The topology is described by storing, for each curved triangle, the two triples of pointers to incident vertices and to adjacent triangles. For each triangle, a scaffolding prism is built, produced by its extreme vertices and normals, which provides a containment volume for the curved interpolating A-patch. When looking for the result of a regularized Boolean operation, the 0-set of a tri-variate polynomial within each such prism is generated, and intersected with the analogous 0-sets of the other curved polyhedron, when two prisms have non-empty intersection. The intersection curves of the boundaries are traced and used to decompose each boundary into the 3 standard classes of subpatches, denoted in, out and on. While tracing the intersection curves, the locally refined triangulation of intersecting patches is produced, and added to the boundary representation. PMID:21516262

Investigation of contact allergy to dental materials by patch testing.

PubMed

Rai, Reena; Dinakar, Devina; Kurian, Swetha S; Bindoo, Y A

2014-07-01

Dental products are widely used by patients and dental personnel alike and may cause problems for both. Dental materials could cause contact allergy with varying manifestations such as burning, pain, stomatitis, cheilitis, ulcers, lichenoid reactions localized to the oral mucosa in patients, and hand dermatitis in dental personnel. Patch testing with the dental series comprising commonly used materials can be used to detect contact allergies to dental materials. This study aimed to identify contact allergy among patients who have oral mucosal lesions after dental treatment and among dental personnel who came in contact with these materials. Twenty patients who had undergone dental procedures with symptoms of oral lichen planus, oral stomatitis, burning mouth, and recurrent aphthosis, were included in the study. Dental personnel with history of hand dermatitis were also included in the study. Patch testing was performed using Chemotechnique Dental Series and results interpreted as recommended by the International Contact Dermatitis Research Group (ICDRG). Out of 13 patients who had undergone dental treatment/with oral symptoms, six patients with stomatitis, lichenoid lesions, and oral ulcers showed positive patch tests to a variety of dental materials, seven patients with ulcers had negative patch tests, seven dental personnel with hand dermatitis showed multiple allergies to various dental materials, and most had multiple positivities. The patch test is a useful, simple, noninvasive method to detect contact allergies among patients and among dental personnel dealing with these products. Long term studies are necessary to establish the relevance of these positive patch tests by eliminating the allergic substances, identifying clinical improvement, and substituting with nonallergenic materials.

Unusual case of choking due to assassin bug ( Cydnocoris gilvus).

PubMed

Sonar, Vaibhav; Patil, Sachin

2018-01-01

Choking is a form of asphyxia which is caused by an obstruction within the air passages. Here, we report a case of obstruction of the upper respiratory tract due to assassin bug ( Cydnocoris gilvus) where allegations of medical negligence were made by relatives of the deceased. Autopsy findings demonstrated that an insect was present inside the larynx, lodged at the epiglottis. Multiple haemorrhagic patches were present at the base of the tongue, larynx, epiglottis, vocal cords and tracheal bifurcation. As Reduviidae can be successfully used as a biological pest-control agents, they should be used with due precaution.

Positive relationship-intensity of response to p-phenylenediamine on patch testing and cross-reactions with related allergens.

PubMed

Thomas, Bjorn R; White, Ian R; McFadden, John P; Banerjee, Piu

2014-08-01

Hair dye exposure is the most common cause of sensitization to p-phenylenediamine (PPD). Cross-reactions with structurally related allergens occur. It is suggested that a stronger patch test reaction (3+ rather than 1+) to PPD (usually tested as 1% petrolatum) is associated with an increased propensity for cross-reactions. In this article we will demonstrate this association. Of 230 patients with allergic reactions to PPD on patch testing identified during 2007-2012 from clinical records, notes for 221 were available for review. Data were collected regarding age, sex, and grade of reaction [International Contact Dermatitis Research Group (ICDRG) criteria] to PPD. Cross-reactions with the following allergens, found in our baseline series, were recorded: Disperse Yellow 3, N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and caine mix. Having excluded 23 doubtful reactions, the reactions from 198 patients were further considered. Of the patients, 75.3% (n = 149) were female, and the mean age was 48.6 years (12-82 years). Of the patients allergic to PPD, 16.6% (n = 33) showed cross-reactions with one or more related allergens. Cross-reactions were seen in 16% with a grade of 1+, 14.5% with a grade of 2+, 28.6% with a grade of 3+ when PPD was tested 1% pet., and 50.0% when PPD was tested at 0.1-0.001%, arbitrarily considered to be 4+ (p = 0.02; Cramér's V = 0.23). An increasing likelihood of reactions to Disperse Yellow 3, IPPD or caine mix was seen with increasing strength of patch test reaction to PPD. The clinical relevance of these cross-reactions is unclear. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Using Deep Slow Slip in New Zealand to Constrain Slip Partitioning

NASA Astrophysics Data System (ADS)

Bartlow, N. M.; Wallace, L. M.

2016-12-01

Underneath New Zealand's North Island, the Pacific plate subducts obliquely beneath the Australian plate. Just to the south, subduction ceases and the plate boundary transitions to the mainly strike-slip, steeply dipping Alpine fault that runs along the South Island. In the region of the southern North Island, the relative plate motion has significant components of both convergence and along strike motion, and slip is partitioned between the main Hikurangi subduction interface and a series of shallower strike-slip faults running thurough the North Island (Wallace and Beavan, GRL, 2010). This region also hosts deep ( 50 km), long duration ( 1 year) slow slip events (SSEs). From early 2013 to early 2016, continuous GPS stations maintained by GeoNet in this region recorded two such deep SSEs on the Hikurangi megathrust. The first SSE occurred on the Kapiti patch, just southwest of the North Island coast. SSEs previous occurred here in 2003 and 2008 (Wallace and Beavan, JGR, 2010). The 2014 Kapiti SSE is unique because it was rapidly decelerated following increased normal stress (clamping) caused by a nearby M 6.3 earthquake (Wallace et al., GRL, 2014). However, GPS data indicates that slip did not stop entirely, and soon after the Manawatu slow slip patch just to the northeast ruptured in another SSE. This patch previously had large SSEs in 2004/2005 and 2010/2011. Given the previous repeat interval of 5.5 years, the 2014/2015 Manawatu SSE is early; however, the record is very short. Here we show Network Inversion Filter derived models of slow slip for the various phases of the Kapiti and Manawatu SSEs, which indicate a possible continuous migration of slip from the Kapiti SSE patch to the Manawatu SSE patch, and we quantify the shear stress increase on the Manawatu patch after the Kapiti SSE. Additionally, we explore allowing the Network Inversion Filter to vary the direction of slip on the plate interface to better fit the data. We estimate how much of the strike-slip and dip-slip components of the relative plate motion are being accommodated by the main thrust interface, and infer how much slip is being accommodated by the strike-slip faults and forearc rotation. We compare our results to those from prior block models of inter-SSE data (Wallace et al., G3, 2009) and explore the implications for seismic hazard assessment in this region.

Comparison of transdermal diclofenac patch with oral diclofenac as an analgesic modality following multiple premolar extractions in orthodontic patients: A cross over efficacy trial

PubMed Central

Bhaskar, Hemant; Kapoor, Pranav; Ragini

2010-01-01

Aims: This study was performed to compare the degree of post operative analgesia, patient compliance, and frequency of adverse events with the use of oral diclofenac tablets and transdermal diclofenac patch following multiple premolar extractions in patients undergoing orthodontic treatment. Materials and Methods: Twenty young pre-orthodontic patients requiring bilateral maxillary and mandibular first premolar extractions were selected for the study. The right maxillary and mandibular first premolars were extracted first and 50 mg oral diclofenac sodium tablets were prescribed to be taken thrice a day for three days. In the next appointment, the contralateral first premolars were extracted and a 100 mg transdermal diclofenac patch was applied once a day for three days. Pain relief and pain intensity with both the diclofenac formulations was recorded for each of the three postoperative days using 5-point Verbal Pain Intensity and Pain Relief Score Charts. Results and Conclusions: Statistical analyses revealed that there was a gradual increase in pain relief scores and a gradual decrease in pain intensity scores with the use of oral diclofenac tablets as well as with the transdermal patch. However, subjects reported that they were more comfortable using the transdermal patch particularly due to the once-a-day application and lesser frequency of systemic adverse effects. Results of this study indicate that the transdermal diclofenac patch provides as potent analgesia as the oral diclofenac tablets with the added advantage of better patient compliance and may be used for routine post extraction analgesia. PMID:22114407

[Selection of distance thresholds of urban forest landscape connectivity in Shenyang City].

PubMed

Liu, Chang-fu; Zhou, Bin; He, Xing-yuan; Chen, Wei

2010-10-01

By using the QuickBird remote sensing image interpretation data of urban forests in Shenyang City in 2006, and with the help of geographical information system, this paper analyzed the landscape patches of the urban forests in the area inside the third ring-road of Shenyang. Based on the habitat availability and the dispersal potential of animal and plant species, 8 distance thresholds (50, 100, 200, 400, 600, 800, 1000, and 1200 m) were selected to compute the integral index of connectivity, probability of connectivity, and important value of the landscape patches, and the computed values were used for analyzing and screening the distance thresholds of urban forest landscape connectivity in the City. The results showed that the appropriate distance thresholds of the urban forest landscape connectivity in Shenyang City in 2006 ranged from 100 to 400 m, with 200 m being most appropriate. It was suggested that the distance thresholds should be increased or decreased according to the performability of urban forest landscape connectivity and the different demands for landscape levels.

EVA 5 activity on Flight Day 8 to service the Hubble Space Telescope

NASA Image and Video Library

1997-02-18

S82-E-5718 (18 Feb. 1997) --- Making use of the Remote Manipulator System (RMS) astronauts Mark C. Lee (left), STS-82 payload commander, and Steven L. Smith, mission specialist, perform the final phases of Extravehicular Activity (EVA) duty. Lee holds a patch piece for Bay #10, out of view, toward which the two were headed. A sample of the patch work can be seen on Bay #9 in the upper left quadrant of the picture. This view was taken with an Electronic Still Camera (ESC).

STS-109 MS Newman replace Reaction Wheel assembly during EVA 2

NASA Image and Video Library

2002-03-05

STS109-E-5399 (5 March 2002) --- Astronaut James H. Newman, mission specialist, moves about in the Space Shuttle Columbia's cargo bay while working in tandem with astronaut Michael J. Massimino (out of frame), mission specialist, during the STS-109 mission's second day of extravehicular activity (EVA). Inside Columbia's cabin, astronaut Nancy J. Currie, mission specialist, controlled the Remote Manipulator System (RMS) to assist the two in their work on the Hubble Space Telescope (HST). Part of the giant telescope's base, latched down in the payload bay, can be seen just above Newman. The image was recorded with a digital still camera.

Photorefractive detection of tagged photons in ultrasound modulated optical tomography of thick biological tissues.

PubMed

Ramaz, F; Forget, B; Atlan, M; Boccara, A C; Gross, M; Delaye, P; Roosen, G

2004-11-01

We present a new and simple method to obtain ultrasound modulated optical tomography images in thick biological tissues with the use of a photorefractive crystal. The technique offers the advantage of spatially adapting the output speckle wavefront by analysing the signal diffracted by the interference pattern between this output field and a reference beam, recorded inside the photorefractive crystal. Averaging out due to random phases of the speckle grains vanishes, and we can use a fast single photodetector to measure the ultrasound modulated optical contrast. This technique offers a promising way to make direct measurements within the decorrelation time scale of living tissues.

Automated Patch-Clamp Methods for the hERG Cardiac Potassium Channel.

PubMed

Houtmann, Sylvie; Schombert, Brigitte; Sanson, Camille; Partiseti, Michel; Bohme, G Andrees

2017-01-01

The human Ether-a-go-go Related Gene (hERG) product has been identified as a central ion channel underlying both familial forms of elongated QT interval on the electrocardiogram and drug-induced elongation of the same QT segment. Indeed, reduced function of this potassium channel involved in the repolarization of the cardiac action potential can produce a type of life-threatening cardiac ventricular arrhythmias called Torsades de Pointes (TdP). Therefore, hERG inhibitory activity of newly synthetized molecules is a relevant structure-activity metric for compound prioritization and optimization in medicinal chemistry phases of drug discovery. Electrophysiology remains the gold standard for the functional assessment of ion channel pharmacology. The recent years have witnessed automatization and parallelization of the manual patch-clamp technique, allowing higher throughput screening on recombinant hERG channels. However, the multi-well plate format of automatized patch-clamp does not allow visual detection of potential micro-precipitation of poorly soluble compounds. In this chapter we describe bench procedures for the culture and preparation of hERG-expressing CHO cells for recording on an automated patch-clamp workstation. We also show that the sensitivity of the assay can be improved by adding a surfactant to the extracellular medium.

Nanoplasmonic lenses for bacteria sorting (Presentation Recording)

NASA Astrophysics Data System (ADS)

Zhu, Xiangchao; Yanik, Ahmet A.

2015-08-01

We demonstrate that patches of two dimensional arrays of circular plasmonic nanoholes patterned on gold-titanium thin film enables subwavelength focusing of visible light in far field region. Efficient coupling of the light with the excited surface plasmon at metal dielectric interface results in strong light transmission. As a result, surface plasmon plays an important role in the far field focusing behavior of the nanohole-aperture patches device. Furthermore, the focal length of the focused beam was found to be predominantly dependent on the overall size of the patch, which is in good agreement with that calculated by Rayleigh-Sommerfield integral formula. The focused light beam can be utilized to separate bio-particles in the dynamic range from 0.1 μm to 1 μm through mainly overcoming the drag force induced by fluid flow. In our proposed model, focused light generated by our plasmonic lenses will push the larger bio-particles in size back to the source of fluid flow and allow the smaller particles to move towards the central aperture of the patch. Such a new kind of plasmonic lenses open up possibility of sorting bacterium-like particles with plasmonic nanolenses, and also represent a promising tool in the field of virology.

Efficacy and Safety of Oral Diclofenac Sustained release Versus Transdermal Diclofenac Patch in Chronic Musculoskeletal Pain: A Randomized, Open Label Trial.

PubMed

Shinde, Viraj Ashok; Kalikar, Mrunalini; Jagtap, Satyajeet; Dakhale, Ganesh N; Bankar, Mangesh; Bajait, Chaitali S; Motghare, Vijay M; Pashilkar, Ashlesha A; Raghute, Latesh B; Khamkar, Ajita D

2017-01-01

To compare the efficacy, safety, and tolerability of transdermal patches of diclofenac sodium with oral diclofenac sustained release (SR) in patients of chronic musculoskeletal MSK pain conditions. The eligible patients were given either transdermal diclofenac patch or tablet diclofenac SR. Pain was assessed at 2 and 4 weeks using a visual analog scale. Adverse events were recorded. Patients with 18-65 years old of either gender with score of ≥4 on a 11-item numeric rating scale-numeric version of visual analog scale for pain with diagnosis of primary osteoarthritis (OA) of the knee or hand of at least 3 months duration, with independent radiological confirmation of OA or having pain associated with other MSK conditions such as soft-tissue rheumatism, cervical and lumbar back pain, and fibromyalgia, of at least 3 months duration were included in this study. Transdermal diclofenac diethylamine patch and tablet diclofenac sodium sustained release (SR) do not significantly differ in the reduction of numerical rating scores at the end of 4 weeks (P = 0.8393). Transdermal diclofenac was equi-efficacious as tablet diclofenac sodium SR in reducing pain due to chronic MSK pain conditions.

Electroactive polyurethane/siloxane derived from castor oil as a versatile cardiac patch, part I: Synthesis, characterization, and myoblast proliferation and differentiation.

PubMed

Baheiraei, Nafiseh; Gharibi, Reza; Yeganeh, Hamid; Miragoli, Michele; Salvarani, Nicolò; Di Pasquale, Elisa; Condorelli, Gianluigi

2016-03-01

Tissue-engineered cardiac patch aims at regenerating an infarcted heart by improving cardiac function and providing mechanical support to the diseased myocardium. In order to take advantages of electroactivity, a new synthetic method was developed for the introduction of an electroactive oligoaniline into the backbone of prepared patches. For this purpose, a series of electroactive polyurethane/siloxane films containing aniline tetramer (AT) was prepared through sol-gel reaction of trimethoxysilane functional intermediate polyurethane prepolymers made from castor oil and poly(ethylene glycol). Physicochemical, mechanical, and electrical conductivity of samples were evaluated and the recorded results were correlated to their structural characteristics. The optimized films were proved to be biodegradable and have tensile properties suitable for cardiac patch application. The embedded AT moieties in the backbone of the prepared samples preserved their electroactivity with the electrical conductivity in the range of 10 -4 S/cm. The prepared films were compatible with proliferation of C2C12 and had potential for enhancing myotube formation even without external electrical stimulation. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 775-787, 2016. © 2015 Wiley Periodicals, Inc.

Protein kinase C enhances the swelling-induced chloride current in human atrial myocytes.

PubMed

Li, Ye-Tao; Du, Xin-Ling

2016-06-01

Swelling-activated chloride currents (ICl.swell) are thought to play a role in several physiologic and pathophysiologic processes and thus represent a target for therapeutic approaches. However, the mechanism of ICl.swell regulation remains unclear. In this study, we used the whole-cell patch-clamp technique to examine the role of protein kinase C (PKC) in the regulation of ICl.swell in human atrial myocytes. Atrial myocytes were isolated from the right atrial appendages of patients undergoing coronary artery bypass and enzymatically dissociated. ICl.swell was evoked in hypotonic solution and recorded using the whole-cell patch-clamp technique. The PKC agonist phorbol dibutyrate (PDBu) enhanced ICl.swell in a concentration-dependent manner, which was reversed in isotonic solution and by a chloride current inhibitor, 9-anthracenecarboxylicacid. Furthermore, the PKC inhibitor bis-indolylmaleimide attenuated the effect and 4α-PDBu, an inactive PDBu analog, had no effect on ICl.swell. These results, obtained using the whole-cell patch-clamp technique, demonstrate the ability of PKC to activate ICl,swell in human atrial myocytes. This observation was consistent with a previous study using a single-channel patch-clamp technique, but differed from some findings in other species.

Natural orifice transluminal endoscopic surgery for patients with perforated peptic ulcer.

PubMed

Bonin, Eduardo A; Moran, Erica; Gostout, Christopher J; McConico, Andrea L; Zielinski, Martin; Bingener, Juliane

2012-06-01

Perforation accounts for 70% of deaths attributed to peptic ulcers. Laparoscopic repair is effective but infrequently used. Our aim was to assess how many patients with perforated peptic ulcer could be candidates for a transluminal endoscopic omental patch closure. This retrospective study reviewed patients with perforated peptic ulcer from 2005 to 2010. Demographics, ulcer characteristics, operative procedure, and outcomes were recorded. Candidates for endoscopic transluminal repair were defined as those having undergone omental patch closure of an ulcer of appropriate size and no contraindications to laparoscopy or endoscopy. In the retrospective review, a total of 104 patients were identified; 62% female, mean age = 68 years, mean ASA of 3, and 63% medication-related ulcers. Fifty-nine (63%) had an omental patch (80% open), and 35 (37%) had other procedures. Ten patients had nonoperative management. Thirty-day mortality was 14% and 1 year mortality was 35%. Forty-nine patients (52%) were considered potential candidates for transluminal repair. Sixty-three percent of our patients sustained a medication-related perforation with 1 year mortality of 35%. The majority of patients were treated using open omental patch repair. Transluminal endoscopic repair may provide an additional situation for a minimally invasive approach for a number of these patients.

Does soil fauna like truffles just as humans do? One-year study of biodiversity in natural brûlés of Tuber aestivum Vittad.

PubMed

Pinto, Stefania; Gatti, Fabio; García-Montero, Luis G; Menta, Cristina

2017-04-15

There are numerous aspects related to Tuber species, which have not been explored to date. Tuber aestivum Vitt. is an ectomycorrhizal fungus, that produces an area (called brûlé) around the host plant trunk, where the germination of other plants is inhibited. What happens inside this particular environment is still not sufficiently understood, especially in terms of soil fauna. A previous work showed that there were higher microarthropod abundances outside during the period of maximum activity of the mycelium. The genus Folsomia (Isotomidae Family; Order Collembola) showed higher abundance inside. The aim of this paper is to investigate the effects of brûlé, on soil parameters and soil fauna, during the annual biological cycle of T. aestivum. This study was carried out in nine spontaneous brûlés situated in Northern Italy (Emilia Romagna Region - Piacenza Province). Soil cores were collected in order to perform soil chemical and biological analysis. Moisture content, pH, organic matter content, total organic carbon were analyzed. Biodiversity and soil quality indices were applied. We found higher pH, lower carbon and organic matter content within the brûlé. Soil fauna community also showed some differences, seasonal and inside vs outside the brûlé. Some groups seem to be negatively affected by Tuber while Folsomia genus recorded almost always higher values inside. These results suggest that some organisms, such as some Collembola, might find a favorable environment inside the brûlé, while others - a negative one. However, these results should be compared by other analysis either on other Tuber species and on other soil organisms, such as nematodes and earthworms. Copyright © 2017 Elsevier B.V. All rights reserved.

Reinforcement of integrin-mediated T-Lymphocyte adhesion by TNF-induced Inside-out Signaling

NASA Astrophysics Data System (ADS)

Li, Qian; Huth, Steven; Adam, Dieter; Selhuber-Unkel, Christine

2016-07-01

Integrin-mediated leukocyte adhesion to endothelial cells is a crucial step in immunity against pathogens. Whereas the outside-in signaling pathway in response to the pro-inflammatory cytokine tumour necrosis factor (TNF) has already been studied in detail, little knowledge exists about a supposed TNF-mediated inside-out signaling pathway. In contrast to the outside-in signaling pathway, which relies on the TNF-induced upregulation of surface molecules on endothelium, inside-out signaling should also be present in an endothelium-free environment. Using single-cell force spectroscopy, we show here that stimulating Jurkat cells with TNF significantly reinforces their adhesion to fibronectin in a biomimetic in vitro assay for cell-surface contact times of about 1.5 seconds, whereas for larger contact times the effect disappears. Analysis of single-molecule ruptures further demonstrates that TNF strengthens sub-cellular single rupture events at short cell-surface contact times. Hence, our results provide quantitative evidence for the significant impact of TNF-induced inside-out signaling in the T-lymphocyte initial adhesion machinery.

Variation in aluminium patch test reactivity over time.

PubMed

Siemund, Ingrid; Mowitz, Martin; Zimerson, Erik; Bruze, Magnus; Hindsén, Monica

2017-11-01

Contact allergy to aluminium has been reported more frequently in recent years. It has been pointed out that positive patch test reactions to aluminium may not be reproducible on retesting. To investigate possible variations in patch test reactivity to aluminium over time. Twenty-one adults, who had previously reacted positively to aluminium, were patch tested with equimolar dilution series in pet. of aluminium chloride hexahydrate and aluminium lactate, four times over a period of 8 months. Thirty-six of 84 (43%) serial dilution tests with aluminium chloride hexahydrate and 49 of 84 (58%) serial dilution tests with aluminium lactate gave negative results. The range of reactivity varied between a negative reaction to aluminium chloride hexahydrate at 10% and/or to aluminium lactate at 12%, and a positive reaction to aluminium chloride hexahydrate at 0.1% and/or to aluminium lactate at 0.12%. The highest individual difference in test reactivity noticed was 320-fold when the two most divergent minimal eliciting concentrations were compared. The patch test reactivity to aluminium varies over time. Aluminium-allergic individuals may have false-negative reactions. Therefore, retesting with aluminium should be considered when there is a strong suspicion of aluminium contact allergy. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Image segregation in strabismic amblyopia.

PubMed

Levi, Dennis M

2007-06-01

Humans with naturally occurring amblyopia show deficits thought to involve mechanisms downstream of V1. These include excessive crowding, abnormal global image processing, spatial sampling and symmetry detection and undercounting. Several recent studies suggest that humans with naturally occurring amblyopia show deficits in global image segregation. The current experiments were designed to study figure-ground segregation in amblyopic observers with documented deficits in crowding, symmetry detection, spatial sampling and counting, using similar stimuli. Observers had to discriminate the orientation of a figure (an "E"-like pattern made up of 17 horizontal Gabor patches), embedded in a 7x7 array of Gabor patches. When the 32 "background" patches are vertical, the "E" pops-out, due to segregation by orientation and performance is perfect; however, if the background patches are all, or mostly horizontal, the "E" is camouflaged, and performance is random. Using a method of constant stimuli, we varied the number of "background" patches that were vertical and measured the probability of correct discrimination of the global orientation of the E (up/down/left/right). Surprisingly, amblyopes who showed strong crowding and deficits in symmetry detection and counting, perform normally or very nearly so in this segregation task. I therefore conclude that these deficits are not a consequence of abnormal segregation of figure from background.

Magnetostrictive patch sensor system for battery-less real-time measurement of torsional vibrations of rotating shafts

NASA Astrophysics Data System (ADS)

Lee, Jun Kyu; Seung, Hong Min; Park, Chung Il; Lee, Joo Kyung; Lim, Do Hyeong; Kim, Yoon Young

2018-02-01

Real-time uninterrupted measurement for torsional vibrations of rotating shafts is crucial for permanent health monitoring. So far, strain gauge systems with telemetry units have been used for real-time monitoring. However, they have a critical disadvantage in that shaft operations must be stopped intermittently to replace telemetry unit batteries. To find an alternative method to carry out battery-less real-time measurement for torsional vibrations of rotating shafts, a magnetostrictive patch sensor system was proposed in the present study. Since the proposed sensor does not use any powered telemetry system, no battery is needed and thus there is no need to stop rotating shafts for battery replacement. The proposed sensor consists of magnetostrictive patches and small magnets tightly bonded onto a shaft. A solenoid coil is placed around the shaft to convert magnetostrictive patch deformation by shaft torsional vibration into electric voltage output. For sensor design and characterization, investigations were performed in a laboratory on relatively small-sized stationary solid shaft. A magnetostrictive patch sensor system was then designed and installed on a large rotating propulsion shaft of an LPG carrier ship in operation. Vibration signals were measured using the proposed sensor system and compared to those measured with a telemetry unit-equipped strain gauge system.

Identification of active sources inside cavities using the equivalent source method-based free-field recovery technique

NASA Astrophysics Data System (ADS)

Bi, Chuan-Xing; Hu, Ding-Yu; Zhang, Yong-Bin; Jing, Wen-Qian

2015-06-01

In previous studies, an equivalent source method (ESM)-based technique for recovering the free sound field in a noisy environment has been successfully applied to exterior problems. In order to evaluate its performance when applied to a more general noisy environment, that technique is used to identify active sources inside cavities where the sound field is composed of the field radiated by active sources and that reflected by walls. A patch approach with two semi-closed surfaces covering the target active sources is presented to perform the measurements, and the field that would be radiated by these target active sources into free space is extracted from the mixed field by using the proposed technique, which will be further used as the input of nearfield acoustic holography for source identification. Simulation and experimental results validate the effectiveness of the proposed technique for source identification in cavities, and show the feasibility of performing the measurements with a double layer planar array.

Series resistance compensation for whole-cell patch-clamp studies using a membrane state estimator

PubMed Central

Sherman, AJ; Shrier, A; Cooper, E

1999-01-01

Whole-cell patch-clamp techniques are widely used to measure membrane currents from isolated cells. While suitable for a broad range of ionic currents, the series resistance (R(s)) of the recording pipette limits the bandwidth of the whole-cell configuration, making it difficult to measure rapid ionic currents. To increase bandwidth, it is necessary to compensate for R(s). Most methods of R(s) compensation become unstable at high bandwidth, making them hard to use. We describe a novel method of R(s) compensation that overcomes the stability limitations of standard designs. This method uses a state estimator, implemented with analog computation, to compute the membrane potential, V(m), which is then used in a feedback loop to implement a voltage clamp; we refer to this as state estimator R(s) compensation. To demonstrate the utility of this approach, we built an amplifier incorporating state estimator R(s) compensation. In benchtop tests, our amplifier showed significantly higher bandwidths and improved stability when compared with a commercially available amplifier. We demonstrated that state estimator R(s) compensation works well in practice by recording voltage-gated Na(+) currents under voltage-clamp conditions from dissociated neonatal rat sympathetic neurons. We conclude that state estimator R(s) compensation should make it easier to measure large rapid ionic currents with whole-cell patch-clamp techniques. PMID:10545359

Rock Outcrops Redistribute Organic Carbon and Nutrients to Nearby Soil Patches in Three Karst Ecosystems in SW China

PubMed Central

Wang, Dianjie; Shen, Youxin; Li, Yuhui; Huang, Jin

2016-01-01

Emergent rock outcrops are common in terrestrial ecosystems. However, little research has been conducted regarding their surface function in redistributing organic carbon and nutrient fluxes to soils nearby. Water that fell on and ran off 10 individual rock outcrops was collected in three 100 × 100 m plots within a rock desertification ecosystem, an anthropogenic forest ecosystem, and a secondary forest ecosystem between June 2013 and June 2014 in Shilin, SW China. The concentrations of total organic carbon (TOC), total nitrogen (N), total phosphorus (P), and potassium (K) in the water samples were determined during three seasons, and the total amounts received by and flowing out from the outcrops were calculated. In all three ecosystems, TOC and N, P, and K were found throughout the year in both the water received by and delivered to nearby soil patches. Their concentrations and amounts were generally greater in forested ecosystems than in the rock desertification ecosystem. When rock outcrops constituted a high percentage (≥ 30%) of the ground surface, the annual export of rock outcrop runoff contributed a large amount of organic carbon and N, P, and K nutrients to soil patches nearby by comparison to the amount soil patches received via atmospheric deposition. These contributions may increase the spatial heterogeneity of soil fertility within patches, as rock outcrops of different sizes, morphologies, and emergence ratios may surround each soil patch. PMID:27509199

Transmucosal delivery of domperidone from bilayered buccal patches: in vitro, ex vivo and in vivo characterization.

PubMed

Palem, Chinna Reddy; Gannu, Ramesh; Doodipala, Narender; Yamsani, Vamshi Vishnu; Yamsani, Madhusudan Rao

2011-10-01

Bilayered mucoadhesive buccal patches for systemic administration of domperidone (DOM), a dopamine-receptor (D(2)) antagonist, were developed using hydroxy propyl methyl cellulose and PVPK30 as a primary layer and Eudragit RLPO and PEO as a secondary layer. Ex vivo drug permeation through porcine buccal membrane was performed. Bilayered buccal patches were developed by solvent casting technique and evaluated for in vitro drug release, moisture absorption, mechanical properties, surface pH, in vitro bioadhesion, in vivo residence time and ex vivo permeation of DOM through porcine buccal membrane from a bilayered buccal patch. Formulation DB4 was associated with 99.5% drug release with a higuchi model release profile and 53.9% of the drug had permeated in 6 h, with a flux of 0.492 mg/h/cm(2) through porcine buccal membrane. DB4 showed 5.58 N and 3.28 mJ peak detachment force and work of adhesion, respectively. The physicochemical interactions between DOM and the polymer were investigated by differential scanning calorimetry (DSC) and fourier transform infrared (FTIR) Spectroscopy. DSC and FTIR studies revealed no interaction between drug and polymer. Stability studies for optimized patch DB4 was carried out at 40°C/75% relative humidity. The formulations were found to be stable over a period of 3 months with respect to drug content, in vitro release and ex vivo permeation through porcine buccal membrane. The results indicate that suitable bilayered mucoadhesive buccal patches with desired permeability could be prepared.

Can exposure limitations for well-known contact allergens be simplified? An analysis of dose-response patch test data.

PubMed

Fischer, Louise Arup; Menné, Torkil; Voelund, Aage; Johansen, Jeanne Duus

2011-06-01

Allergic contact dermatitis is triggered by chemicals in the environment. Primary prevention is aimed at minimizing the risk of induction, whereas secondary and tertiary prevention are aimed at reducing elicitation. To identify the elicitation doses that will elicit an allergic reaction in 10% of allergic individuals under patch test conditions (ED(10) patch test) for different allergens, and to compare the results with those for different allergens and with animal data indicating sensitizing potency from the literature. The literature was searched for patch test elicitation studies that fulfilled six selected criteria. The elicitation doses were calculated, and fitted dose-response curves were drawn. Sixteen studies with eight different allergens-methylchloroisothiazolinone/ methylisothiazolinone, formaldehyde, nickel, cobalt, chromium, isoeugenol, hydroxyiso hexyl 3-cyclohexene carboxaldehyde, and methyldibromo glutaronitrile-were selected. The median ED(10) value was 0.835 µg/cm(2). The ED(10) patch test values were all within a factor of 7 from the lowest to the highest value, leaving out three outliers. No obvious patterns between the sensitization and elicitation doses for the allergens were found. We found a rather small variation in the ED(10) patch test between the allergens, and no clear relationship between induction potency and elicitation threshold of a range of allergens. This knowledge may stimulate thoughts on introducing a generic approach for limitations in exposure to well-known allergens. © 2011 John Wiley & Sons A/S.

Outcomes of 3 hours part-time occlusion treatment combined with near activities among children with unilateral amblyopia.

PubMed

Alotaibi, Abdullah G; Fawazi, Samah M; Alenazy, Badriah R; Abu-Amero, Khaled K

2012-04-01

To evaluate the outcome of part-time occlusion therapy with or without near activities in monocular amblyopic patients. One hundred and thirty patients who prescribed daily occlusion therapy (part-time occlusion) were followed-up for a 12-week period. The study was carried out in the Pediatric Ophthalmology and Orthoptics Clinics of King Abdul-Aziz University Hospital, Riyadh, Saudi Arabia for the period from January to November 2010. Sixty-five patients were recommended to undertake the 3 hours of near visual activities (such as reading a book during patching) while the other 65 patients were not advised to do any near activity. Main outcome measures were best corrected visual acuity (VA) for both groups and line improvement. The total line of VA improved from baseline by an average of 6.7+/-2.37 line log MAR (logarithm of the minimum angle of resolution) units in the group of patching with near activities and by an average of 5.3+/- 2.04 line log MAR units in the group of patching without near activities. All type of amblyopia (strabismic, anisometropic, and mixed types of amblyopia) improved significantly after patching with near activities. Both moderate and severe amblyopia improved significantly in the group of near activities compared with the group without near activities. Performing near activities while patching in the treatment of anisometropic, stabismic, or combined amblyopia improves the VA outcome more than patching alone.

Performance analysis of smart laminated composite plate integrated with distributed AFC material undergoing geometrically nonlinear transient vibrations

NASA Astrophysics Data System (ADS)

Shivakumar, J.; Ashok, M. H.; Khadakbhavi, Vishwanath; Pujari, Sanjay; Nandurkar, Santosh

2018-02-01

The present work focuses on geometrically nonlinear transient analysis of laminated smart composite plates integrated with the patches of Active fiber composites (AFC) using Active constrained layer damping (ACLD) as the distributed actuators. The analysis has been carried out using generalised energy based finite element model. The coupled electromechanical finite element model is derived using Von Karman type nonlinear strain displacement relations and a first-order shear deformation theory (FSDT). Eight-node iso-parametric serendipity elements are used for discretization of the overall plate integrated with AFC patch material. The viscoelastic constrained layer is modelled using GHM method. The numerical results shows the improvement in the active damping characteristics of the laminated composite plates over the passive damping for suppressing the geometrically nonlinear transient vibrations of laminated composite plates with AFC as patch material.

Green infrastructure development at European Union's eastern border: Effects of road infrastructure and forest habitat loss.

PubMed

Angelstam, Per; Khaulyak, Olha; Yamelynets, Taras; Mozgeris, Gintautas; Naumov, Vladimir; Chmielewski, Tadeusz J; Elbakidze, Marine; Manton, Michael; Prots, Bohdan; Valasiuk, Sviataslau

2017-05-15

The functionality of forest patches and networks as green infrastructure may be affected negatively both by expanding road networks and forestry intensification. We assessed the effects of (1) the current and planned road infrastructure, and (2) forest loss and gain, on the remaining large forest landscape massifs as green infrastructure at the EU's eastern border region in post-socialistic transition. First, habitat patch and network functionality in 1996-98 was assessed using habitat suitability index modelling. Second, we made expert interviews about road development with planners in 10 administrative regions in Poland, Belarus and Ukraine. Third, forest loss and gain inside the forest massifs, and gain outside them during the period 2001-14 were measured. This EU cross-border region hosts four remaining forest massifs as regional green infrastructure hotspots. While Poland's road network is developing fast in terms of new freeways, city bypasses and upgrades of road quality, in Belarus and Ukraine the focus is on maintenance of existing roads, and no new corridors. We conclude that economic support from the EU, and thus rapid development of roads in Poland, is likely to reduce the permeability for wildlife of the urban and agricultural matrix around existing forest massifs. However, the four identified forest massifs themselves, forming the forest landscape green infrastructure at the EU's east border, were little affected by road development plans. In contrast, forest loss inside massifs was high, especially in Ukraine. Only in Poland forest loss was balanced by gain. Forest gain outside forest massifs was low. To conclude, pro-active and collaborative spatial planning across different sectors and countries is needed to secure functional forest green infrastructure as base for biodiversity conservation and human well-being. Copyright © 2017. Published by Elsevier Ltd.

Solar Polar Jets Driven by Magnetic Reconnection, Gravity, and Wind

NASA Astrophysics Data System (ADS)

DeVore, C. Richard; Karpen, Judith T.; Antiochos, Spiro K.

2014-06-01

Polar jets are dynamic, narrow, radially extended structures observed in solar EUV emission near the limb. They originate within the open field of coronal holes in “anemone” regions, which are intrusions of opposite magnetic polarity. The key topological feature is a magnetic null point atop a dome-shaped fan surface of field lines. Applied stresses readily distort the null into a current patch, eventually inducing interchange reconnection between the closed and open fields inside and outside the fan surface (Antiochos 1996). Previously, we demonstrated that magnetic free energy stored on twisted closed field lines inside the fan surface is released explosively by the onset of fast reconnection across the current patch (Pariat et al. 2009, 2010). A dense jet comprised of a nonlinear, torsional Alfvén wave is ejected into the outer corona along the newly reconnected open field lines. Now we are extending those exploratory simulations by including the effects of solar gravity, solar wind, and expanding spherical geometry. We find that the model remains robust in the resulting more complex setting, with explosive energy release and dense jet formation occurring in the low corona due to the onset of a kink-like instability, as found in the earlier Cartesian, gravity-free, static-atmosphere cases. The spherical-geometry jet including gravity and wind propagates far more rapidly into the outer corona and inner heliosphere than a comparison jet simulation that excludes those effects. We report detailed analyses of our new results, compare them with previous work, and discuss the implications for understanding remote and in-situ observations of solar polar jets.This work was supported by NASA’s LWS TR&T program.

Releases of Psyttalia fletcheri (Hymenoptera: Braconidae) and sterile flies to suppress melon fly (Diptera: Tephritidae) in Hawaii.

PubMed

Vargas, Roger I; Long, Jay; Miller, Neil W; Delate, Kathleen; Jackson, Charles G; Uchida, Grant K; Bautista, Renato C; Harris, Ernie J

2004-10-01

Ivy gourd, Coccinia grandis (L.) Voigt, patches throughout Kailua-Kona, Hawaii Island, HI, were identified as persistent sources of melon fly, Bactrocera cucurbitae (Coquillett). These patches had a low incidence of Psyttalia fletcheri (Silvestri), its major braconid parasitoid natural enemy in Hawaii, and were used to evaluate augmentative releases of P. fletcheri against melon fly. In field cage studies of releases, numbers of melon flies emerging from ivy gourd fruit placed inside treatment cages were reduced up to 21-fold, and numbers of parasitoids were increased 11-fold. In open field releases of P. fletcheri into ivy gourd patches, parasitization rates were increased 4.7 times in release plots compared with those in control plots. However, there was no significant reduction in emergence of melon flies from fruit. In subsequent cage tests with sterile melon flies and P. fletcheri, combinations of sterile flies and P. fletcheri produced the greatest reduction (9-fold) in melon fly emergence from zucchini, Cucurbita pepo L. Reductions obtained with sterile flies alone or in combination with parasitoids were significantly greater than those in the control, whereas those for parasitoids alone were not. Although these results suggest that the effects of sterile flies were greater than those for parasitoids, from a multitactic melon fly management strategy, sterile flies would complement the effects of P. fletcheri. Cost and sustainability of these nonchemical approaches will be examined further in an ongoing areawide pest management program for melon fly in Hawaii.

Using free patches to improve reach of the Oregon Quit Line.

PubMed

Deprey, Mona; McAfee, Tim; Bush, Terry; McClure, Jennifer B; Zbikowski, Susan; Mahoney, Lisa

2009-01-01

For 2 1/2 months, the Oregon Tobacco Quit Line (ORQL) offered a free 2-week starter kit of nicotine patches to all callers. The promotional plan, utilizing Roger's Diffusion of Innovation theory, targeted health plans, local policy makers, media sources, and referral sources, such as healthcare providers. Word-of-mouth advertising was also encouraged using a free patch card, which could be handed out to tobacco users. Six weeks prior to the public launch, information about the initiative was disseminated by e-mailing and sending letters to public and private sector partners. Call volume to the ORQL was monitored 6 months prior to the Free Patch Initiative and immediately following the launch. Demographic characteristics of callers pre- and postinitiative were compared using ORQL data. A media firm tracked earned media generated by the initiative. The Initiative generated free "earned" media attention, increased calls to the ORQL by 12-fold, and reached 1.3% of the smoking population within a 3-month period. Offering a short course of free NRT is an effective way to promote the use of quitlines.

One-pot fabrication of graphene oxide-patched hollow-structured microgel particles in a microcapillary device

NASA Astrophysics Data System (ADS)

Byun, Aram; Jeong, Eun Seon; Kim, Jin Woong

2014-03-01

Microgels are colloidal gel particles that consist of chemically cross-linked three-dimensional polymer networks. They play an essential role in delivery and release of active ingredients in medicine, cosmetics, food, and even autonomic self-healing applications. Despite their wide applicability, permeability control through the hydrogel phase is limited due to its intrinsic loose network nature. Herein, we introduce generation of hollow-structured microgel particles whose interfaces were patched with graphene oxide (GO) sheets. The whole fabrication procedure was carried out in a microcapillary device in a single step. GO sheets have an ability to adhere to both O/W and W/O interfaces. Taking advantages of this behavior, we generated monodisperse O/W/O double emulsion whose interfaces were patched with GO sheets. Solidification of the aqueous middle phase to the hydrogel phase gave rise to uniform GO-patched microgel shell particles. Furthermore, we demonstrated that the permeation of molecules through the shell could be controlled even to small molecular length scales due to the adsorption of GO.

Mechanosensitive activation of K+ channel via phospholipase C-induced depletion of phosphatidylinositol 4,5-bisphosphate in B lymphocytes.

PubMed

Nam, Joo Hyun; Lee, Hoo-Se; Nguyen, Yen Hoang; Kang, Tong Mook; Lee, Sung Won; Kim, Hye-Young; Kim, Sang Jeong; Earm, Yung E; Kim, Sung Joon

2007-08-01

In various types of cells mechanical stimulation of the plasma membrane activates phospholipase C (PLC). However, the regulation of ion channels via mechanosensitive degradation of phosphatidylinositol 4,5-bisphosphate (PIP(2)) is not known yet. The mouse B cells express large conductance background K(+) channels (LK(bg)) that are inhibited by PIP(2). In inside-out patch clamp studies, the application of MgATP (1 mm) also inhibited LK(bg) due to the generation of PIP(2) by phosphoinositide (PI)-kinases. In the presence of MgATP, membrane stretch induced by negative pipette pressure activated LK(bg), which was antagonized by PIP(2) (> 1 microm) or higher concentration of MgATP (5 mm). The inhibition by PIP(2) was partially reversible. However, the application of methyl-beta-cyclodextrin, a cholesterol scavenger disrupting lipid rafts, induced the full recovery of LK(bg) activity and facilitated the activation by stretch. In cell-attached patches, LK(bg) were activated by hypotonic swelling of B cells as well as by negative pressure. The mechano-activation of LK(bg) was blocked by U73122, a PLC inhibitor. Neither actin depolymerization nor the inhibition of lipid phosphatase blocked the mechanical effects. Direct stimulation of PLC by m-3M3FBS or by cross-linking IgM-type B cell receptors activated LK(bg). Western blot analysis and confocal microscopy showed that the hypotonic swelling of WEHI-231 induces tyrosine phosphorylation of PLCgamma2 and PIP(2) hydrolysis of plasma membrane. The time dependence of PIP(2) hydrolysis and LK(bg) activation were similar. The presence of LK(bg) and their stretch sensitivity were also proven in fresh isolated mice splenic B cells. From the above results, we propose a novel mechanism of stretch-dependent ion channel activation, namely, that the degradation of PIP(2) caused by stretch-activated PLC releases LK(bg) from the tonic inhibition by PIP(2).

Phosphatidylinositol 4,5-bisphosphate, cholesterol, and fatty acids modulate the calcium-activated chloride channel TMEM16A (ANO1).

PubMed

De Jesús-Pérez, José J; Cruz-Rangel, Silvia; Espino-Saldaña, Ángeles E; Martínez-Torres, Ataúlfo; Qu, Zhiqiang; Hartzell, H Criss; Corral-Fernandez, Nancy E; Pérez-Cornejo, Patricia; Arreola, Jorge

2018-03-01

The TMEM16A-mediated Ca 2+ -activated Cl - current drives several important physiological functions. Membrane lipids regulate ion channels and transporters but their influence on members of the TMEM16 family is poorly understood. Here we have studied the regulation of TMEM16A by phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), cholesterol, and fatty acids using patch clamp, biochemistry and fluorescence microscopy. We found that depletion of membrane PI(4,5)P2 causes a decline in TMEM16A current that is independent of cytoskeleton, but is partially prevented by removing intracellular Ca 2+ . On the other hand, supplying PI(4,5)P2 to inside-out patches attenuated channel rundown and/or partially rescued activity after channel rundown. Also, depletion (with methyl-β-cyclodextrin M-βCD) or restoration (with M-βCD+cholesterol) of membrane cholesterol slows down the current decay observed after reduction of PI(4,5)P2. Neither depletion nor restoration of cholesterol change PI(4,5)P2 content. However, M-βCD alone transiently increases TMEM16A activity and dampens rundown whereas M-βCD+cholesterol increases channel rundown. Thus, PI(4,5)P2 is required for TMEM16A function while cholesterol directly and indirectly via a PI(4,5)P2-independent mechanism regulate channel function. Stearic, arachidonic, oleic, docosahexaenoic, and eicosapentaenoic fatty acids as well as methyl stearate inhibit TMEM16A in a dose- and voltage-dependent manner. Phosphatidylserine, a phospholipid whose hydrocarbon tails contain stearic and oleic acids also inhibits TMEM16A. Finally, we show that TMEM16A remains in the plasma membrane after treatment with M-βCD, M-βCD+cholesterol, oleic, or docosahexaenoic acids. Thus, we propose that lipids and fatty acids regulate TMEM16A channels through a membrane-delimited protein-lipid interaction. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation of contact allergy to dental materials by patch testing

PubMed Central

Rai, Reena; Dinakar, Devina; Kurian, Swetha S.; Bindoo, Y. A.

2014-01-01

Background: Dental products are widely used by patients and dental personnel alike and may cause problems for both. Dental materials could cause contact allergy with varying manifestations such as burning, pain, stomatitis, cheilitis, ulcers, lichenoid reactions localized to the oral mucosa in patients, and hand dermatitis in dental personnel. Patch testing with the dental series comprising commonly used materials can be used to detect contact allergies to dental materials. Aim: This study aimed to identify contact allergy among patients who have oral mucosal lesions after dental treatment and among dental personnel who came in contact with these materials. Materials and Methods: Twenty patients who had undergone dental procedures with symptoms of oral lichen planus, oral stomatitis, burning mouth, and recurrent aphthosis, were included in the study. Dental personnel with history of hand dermatitis were also included in the study. Patch testing was performed using Chemotechnique Dental Series and results interpreted as recommended by the International Contact Dermatitis Research Group (ICDRG). Results: Out of 13 patients who had undergone dental treatment/with oral symptoms, six patients with stomatitis, lichenoid lesions, and oral ulcers showed positive patch tests to a variety of dental materials, seven patients with ulcers had negative patch tests, seven dental personnel with hand dermatitis showed multiple allergies to various dental materials, and most had multiple positivities. Conclusion: The patch test is a useful, simple, noninvasive method to detect contact allergies among patients and among dental personnel dealing with these products. Long term studies are necessary to establish the relevance of these positive patch tests by eliminating the allergic substances, identifying clinical improvement, and substituting with nonallergenic materials. PMID:25165644

Volume measuring system

NASA Technical Reports Server (NTRS)

Oele, J. S.

1975-01-01

Chamber is designed to be airtight; it includes face mask for person to breathe outside air so that he does not disturb chamber environment. Chamber includes piston to vary air volume inside. Also included are two microphone transducers which record pressure information inside chamber.

Modification of the random forest algorithm to avoid statistical dependence problems when classifying remote sensing imagery

NASA Astrophysics Data System (ADS)

Cánovas-García, Fulgencio; Alonso-Sarría, Francisco; Gomariz-Castillo, Francisco; Oñate-Valdivieso, Fernando

2017-06-01

Random forest is a classification technique widely used in remote sensing. One of its advantages is that it produces an estimation of classification accuracy based on the so called out-of-bag cross-validation method. It is usually assumed that such estimation is not biased and may be used instead of validation based on an external data-set or a cross-validation external to the algorithm. In this paper we show that this is not necessarily the case when classifying remote sensing imagery using training areas with several pixels or objects. According to our results, out-of-bag cross-validation clearly overestimates accuracy, both overall and per class. The reason is that, in a training patch, pixels or objects are not independent (from a statistical point of view) of each other; however, they are split by bootstrapping into in-bag and out-of-bag as if they were really independent. We believe that putting whole patch, rather than pixels/objects, in one or the other set would produce a less biased out-of-bag cross-validation. To deal with the problem, we propose a modification of the random forest algorithm to split training patches instead of the pixels (or objects) that compose them. This modified algorithm does not overestimate accuracy and has no lower predictive capability than the original. When its results are validated with an external data-set, the accuracy is not different from that obtained with the original algorithm. We analysed three remote sensing images with different classification approaches (pixel and object based); in the three cases reported, the modification we propose produces a less biased accuracy estimation.

One-channel Cell-attached Patch-clamp Recording

PubMed Central

Maki, Bruce A.; Cummings, Kirstie A.; Paganelli, Meaghan A.; Murthy, Swetha E.; Popescu, Gabriela K.

2014-01-01

Ion channel proteins are universal devices for fast communication across biological membranes. The temporal signature of the ionic flux they generate depends on properties intrinsic to each channel protein as well as the mechanism by which it is generated and controlled and represents an important area of current research. Information about the operational dynamics of ion channel proteins can be obtained by observing long stretches of current produced by a single molecule. Described here is a protocol for obtaining one-channel cell-attached patch-clamp current recordings for a ligand gated ion channel, the NMDA receptor, expressed heterologously in HEK293 cells or natively in cortical neurons. Also provided are instructions on how to adapt the method to other ion channels of interest by presenting the example of the mechano-sensitive channel PIEZO1. This method can provide data regarding the channel’s conductance properties and the temporal sequence of open-closed conformations that make up the channel’s activation mechanism, thus helping to understand their functions in health and disease. PMID:24961614

Curiosity Low-Angle Self-Portrait at Buckskin Drilling Site on Mount Sharp

NASA Image and Video Library

2015-08-19

This low-angle self-portrait of NASA's Curiosity Mars rover shows the vehicle above the "Buckskin" rock target, where the mission collected its seventh drilled sample. The site is in the "Marias Pass" area of lower Mount Sharp. The scene combines dozens of images taken by Curiosity's Mars Hand Lens Imager (MAHLI) on Aug. 5, 2015, during the 1,065th Martian day, or sol, of the rover's work on Mars. The 92 component images are among MAHLI Sol 1065 raw images at http://mars.nasa.gov/msl/multimedia/raw/?s=1065&camera=MAHLI. For scale, the rover's wheels are 20 inches (50 centimeters) in diameter and about 16 inches (40 centimeters) wide. Curiosity drilled the hole at Buckskin during Sol 1060 (July 30, 2015). Two patches of pale, powdered rock material pulled from Buckskin are visible in this scene, in front of the rover. The patch closer to the rover is where the sample-handling mechanism on Curiosity's robotic arm dumped collected material that did not pass through a sieve in the mechanism. Sieved sample material was delivered to laboratory instruments inside the rover. The patch farther in front of the rover, roughly triangular in shape, shows where fresh tailings spread downhill from the drilling process. The drilled hole, 0.63 inch (1.6 centimeters) in diameter, is at the upper point of the tailings. The rover is facing northeast, looking out over the plains from the crest of a 20-foot (6-meter) hill that it climbed to reach the Marias Pass area. The upper levels of Mount Sharp are visible behind the rover, while Gale Crater's northern rim dominates the horizon on the left and right of the mosaic. A portion of this selfie cropped tighter around the rover is at PIA19808. Another version of the wide view, presented in a projection that shows the horizon as a circle, is at PIA19806. MAHLI is mounted at the end of the rover's robotic arm. For this self-portrait, the rover team positioned the camera lower in relation to the rover body than for any previous full self-portrait of Curiosity. This yielded a view that includes the rover's "belly," as in a partial self-portrait (PIA16137) taken about five weeks after Curiosity's August 2012 landing inside Mars' Gale Crater. Before sending Curiosity the arm-positioning commands for this Buckskin belly panorama, the team previewed the low-angle sequence of camera pointings on a test rover in California. A mosaic from that test is at PIA19810. This selfie at Buckskin does not include the rover's robotic arm beyond a portion of the upper arm held nearly vertical from the shoulder joint. Shadows from the rest of the arm and the turret of tools at the end of the arm are visible on the ground. With the wrist motions and turret rotations used in pointing the camera for the component images, the arm was positioned out of the shot in the frames or portions of frames used in this mosaic. This process was used previously in acquiring and assembling Curiosity self-portraits taken at sample-collection sites "Rocknest" (PIA16468), "John Klein" (PIA16937), "Windjana" (PIA18390) and "Mojave" (PIA19142). MAHLI was built by Malin Space Science Systems, San Diego. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Science Laboratory Project for the NASA Science Mission Directorate, Washington. JPL designed and built the project's Curiosity rover. http://photojournal.jpl.nasa.gov/catalog/PIA19807

Creating Community from the Inside Out: A Concentric Perspective on Collective Artmaking

ERIC Educational Resources Information Center

Blatt-Gross, Carolina

2017-01-01

As the original antidote to social alienation (and its tragic repercussions), community art through its large-scale, public, and collaborative nature has the potential to rebuild a sense of community from the inside out. This concentric notion of community art is addressed at both the individual and classroom level, exploring the origins of…

From the inside Out: Group Work with Women of Color

ERIC Educational Resources Information Center

Short, Ellen L.; Williams, Wendi S.

2014-01-01

This article will present two models for conducting group work with Women of Color (WOC): the SisterCircle Approach and the Group Relations Model. The authors contend that the models, when used together, combine an internal and external focus ("inside out") of group work that can assist group workers to conduct individual and group-level…

A semiarid fruit agroecosystem as a conservation-friendly option for small mammals in an anthropized landscape in Mexico.

PubMed

Riojas-López, Mónica E; Mellink, Eric; Luévano, Jaime

2018-03-01

Many studies have addressed the potential of low-input agroecosystems for biological conservation. However, most have been carried out on annual agroecosystems in temperate, developed countries. As agricultural surface will increase and natural protected areas alone will not warrant the conservation of biodiversity, it is crucial to include different types of agroecosystems in research and conservation efforts. In Mexico, perennial, low-input, fruit-oriented nopal orchards (Opuntia spp.), one of the few crops suitable for semiarid areas, are the 10th out of 61 most important fruit crops grown in the country. We assessed their value for conservation in an anthropized landscape by comparing their rodent assemblages with those in adjacent habitats and determined the influence of the latter on the rodent communities inside them. We live-trapped rodents in 12 orchards and adjacent natural xeric shrubland, grassland, and cropland. We captured 19 different species, of which 17 used the orchards. Four are Mexican endemics. Orchards have higher α diversity, species richness, and abundance than cropland and grassland and are not different from shrubland. The dominant rodent species are the same in orchards and shrubland, and where these two meet they integrate into one habitat. Within-habitat quality is a critical driver of the composition and diversity of rodent communities in the orchards studied, and the neighboring habitats do not modify them substantially. Increasing within-patch heterogeneity beyond a certain level is at the expense of habitat integrity and produces small-scale fragmentation reducing habitat quality. At a landscape scale, orchards contribute importantly to regional rodent diversity compared with other land use types, and appear to increase habitat connectivity between patches of shrubland. Orchards' higher α diversity would give them higher ecological resilience and make them better suited than grassland and cropland to contribute to the conservation of local biota. Nopal orchards should be considered conservation allies and incorporated in regional conservation plans. Regrettably, their future is unwarranted as producers face low revenues and lack of governmental support. Our confirmation that orchards have an important, positive impact on biodiversity can be used as a strong argument to lobby for incentives to safeguard this environmental friendly, low-input agroecosystem. © 2017 by the Ecological Society of America.

Modified automatic R-peak detection algorithm for patients with epilepsy using a portable electrocardiogram recorder.

PubMed

Jeppesen, J; Beniczky, S; Fuglsang Frederiksen, A; Sidenius, P; Johansen, P

2017-07-01

Earlier studies have shown that short term heart rate variability (HRV) analysis of ECG seems promising for detection of epileptic seizures. A precise and accurate automatic R-peak detection algorithm is a necessity in a real-time, continuous measurement of HRV, in a portable ECG device. We used the portable CE marked ePatch® heart monitor to record the ECG of 14 patients, who were enrolled in the videoEEG long term monitoring unit for clinical workup of epilepsy. Recordings of the first 7 patients were used as training set of data for the R-peak detection algorithm and the recordings of the last 7 patients (467.6 recording hours) were used to test the performance of the algorithm. We aimed to modify an existing QRS-detection algorithm to a more precise R-peak detection algorithm to avoid the possible jitter Qand S-peaks can create in the tachogram, which causes error in short-term HRVanalysis. The proposed R-peak detection algorithm showed a high sensitivity (Se = 99.979%) and positive predictive value (P+ = 99.976%), which was comparable with a previously published QRS-detection algorithm for the ePatch® ECG device, when testing the same dataset. The novel R-peak detection algorithm designed to avoid jitter has very high sensitivity and specificity and thus is a suitable tool for a robust, fast, real-time HRV-analysis in patients with epilepsy, creating the possibility for real-time seizure detection for these patients.

Training a cell-level classifier for detecting basal-cell carcinoma by combining human visual attention maps with low-level handcrafted features

PubMed Central

Corredor, Germán; Whitney, Jon; Arias, Viviana; Madabhushi, Anant; Romero, Eduardo

2017-01-01

Abstract. Computational histomorphometric approaches typically use low-level image features for building machine learning classifiers. However, these approaches usually ignore high-level expert knowledge. A computational model (M_im) combines low-, mid-, and high-level image information to predict the likelihood of cancer in whole slide images. Handcrafted low- and mid-level features are computed from area, color, and spatial nuclei distributions. High-level information is implicitly captured from the recorded navigations of pathologists while exploring whole slide images during diagnostic tasks. This model was validated by predicting the presence of cancer in a set of unseen fields of view. The available database was composed of 24 cases of basal-cell carcinoma, from which 17 served to estimate the model parameters and the remaining 7 comprised the evaluation set. A total of 274 fields of view of size 1024×1024  pixels were extracted from the evaluation set. Then 176 patches from this set were used to train a support vector machine classifier to predict the presence of cancer on a patch-by-patch basis while the remaining 98 image patches were used for independent testing, ensuring that the training and test sets do not comprise patches from the same patient. A baseline model (M_ex) estimated the cancer likelihood for each of the image patches. M_ex uses the same visual features as M_im, but its weights are estimated from nuclei manually labeled as cancerous or noncancerous by a pathologist. M_im achieved an accuracy of 74.49% and an F-measure of 80.31%, while M_ex yielded corresponding accuracy and F-measures of 73.47% and 77.97%, respectively. PMID:28382314

Lipid bilayer mechanics in a pipette with glass-bilayer adhesion.

PubMed

Ursell, Tristan; Agrawal, Ashutosh; Phillips, Rob

2011-10-19

Electrophysiology is a central tool for measuring how different driving forces (e.g., ligand concentration, transmembrane voltage, or lateral tension) cause a channel protein to gate. Upon formation of the high resistance seal between a lipid bilayer and a glass pipette, the so-called "giga-seal", channel activity can be recorded electrically. In this article, we explore the implications of giga-seal formation on the mechanical state of a lipid bilayer patch. We use a mechanical model for the free energy of bilayer geometry in the presence of glass-bilayer adhesion to draw three potentially important conclusions. First, we use our adhesion model to derive an explicit relationship between applied pressure and patch shape that is consistent with the Laplace-Young Law, giving an alternative method of calculating patch tension under pressure. With knowledge of the adhesion constant, which we find to be in the range ∼0.4-4 mN/m, and the pipette size, one can precisely calculate the patch tension as a function of pressure, without the difficultly of obtaining an optical measurement of the bilayer radius of curvature. Second, we use data from previous electrophysiological experiments to show that over a wide range of lipids, the resting tension on a electrophysiological patch is highly variable and can be 10-100 times higher than estimates of the tension in a typical cell membrane. This suggests that electrophysiological experiments may be systematically altering channel-gating characteristics and querying the channels under conditions that are not the same as their physiological counterparts. Third, we show that reversible adhesion leads to a predictable change in the population response of gating channels in a bilayer patch. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Hydrodynamic Environment and Ecosystem Diversity at two Deep-Sea Marine Protected Areas in Southern Biscay

NASA Astrophysics Data System (ADS)

González-Pola, C.; Ivey, G. N.; Jones, N. L.; Sanchez, F.; Kelly, S. M.; Bluteau, C.; Somavilla, R.

2016-02-01

Two nearby offshore deep sea areas in Southern Bay of Biscay (northern Spain), hosting valuable ecosystems, have been recently declared marine protected areas. The first one is Le Danois Bank, a seamount-like feature connected to the continental shelf by a saddle. The second one is the Aviles Canyon System (ACS) that breaks the continuity of the northern Spanish continental shelf. A number of observational multidisciplinary programs carried out within the last decade allowed a detailed identification of habitats and biological communities. As a long-term goal these programs aimed to understand the ecosystem functioning as a whole with the implicit focus in associated circulation and dynamics. The observational record includes deep sea photogrametry as well as standard hydrography and long-term mooring lines. A lander system provided high-frequency currents and thermal structure tens meters above bottom together with time lapse photographs at selected sites. Different characteristic habitats from sedimentary to rocky, associated with different fisheries, were described both in Le Danois Bank and the ACS. These include sponge aggregations and deep water corals. Noteworthy structured coral reefs only appeared in a relatively small area in one of the tributaries of the ACS (La Gaviera Canyon), where local near-bottom currents were stronger than anywhere else in the region. The development and violent breaking of an internal tidal bore was the main feature of such hotspot. Analytic estimates confirmed that La Gaviera is the only canyon were large patches of the seafloor are critical or near-critical to the semidiurnal internal tide and nearby upper flanks show also large patches of critical seafloor and large body forcing. A year-long near-bottom current record captured the development of three benthic storms, events lasting several days in which currents increases up to 3-fold the tidal max speeds and direction swings rapidly, losing the uniformity of tidal regime.

Multisclae heterogeneity of the 2011 Tohoku-oki earthquake by inversion

NASA Astrophysics Data System (ADS)

Aochi, H.; Ulrich, T.; Cornier, G.

2012-12-01

Earthquake fault heterogeneity is often studied on a set of subfaults in kinematic inversion, while it is sometimes described with spatially localized geometry. Aochi and Ide (EPS, 2011) and Ide and Aochi (submitted to Pageoph and AGU, 2012) apply a concept of multi-scale heterogeneity to simulate the dynamic rupture process of the 2011 Tohoku-oki earthquake, introducing circular patches of different dimension in fault fracture energy distribution. Previously the patches are given by the past moderate earthquakes in this region, and this seems to be consistent with the evolution process of this mega earthquake, although a few patches, in particular, the largest patch, had not been known previously. In this study, we try to identify patches by inversion. As demonstrated in several earthquakes including the 2010 Maule (M8.8) earthquake, it is possible to indentify two asperities of ellipse kinematically or dynamically (e.g. Ruiz and Madariaga, 2011, and so on). In the successful examples, different asperities are rather visible, separated in space. However the Tohoku-oki earthquake has hierarchical structure of heterogeneity. We apply the Genetic Algorithm to inverse the model parameters from the ground motions (K-net and Kik-net from NIED) and the high sampling GPS (GSI). Starting from low frequency ranges (> 50 seconds), we obtain an ellipse corresponding to M9 event located around the hypocenter, coherent with the previous result by Madariaga et al. (pers. comm.). However it is difficult to identify the second smaller with few constraints. This is mainly because the largest covers the entire rupture area and any smaller patch improves the fitting only for the closer stations. Again, this needs to introduce the multi-scale concept in inversion procedure. Instead of finding the largest one at first, we have to start to extract rather smaller moderate patches from the beginning of the record, following the rupture process.

Endovascular Patch Embolization for Blood Blister-Like Aneurysms in Dorsal Segment of Internal Carotid Artery.

PubMed

Hao, Xudong; Li, Guilin; Ren, Jian; Li, Jingwei; He, Chuan; Zhang, Hong-Qi

2018-05-01

Blood blister-like aneurysms (BBAs) in the dorsal segment of the internal carotid artery are fragile and difficult to treat, and the optimal treatment for BBAs is still controversial. We report clinical and angiographic results with procedural details for the treatment of BBA by using the endovascular patch embolization method. We retrospectively reviewed patients who presented with subarachnoid hemorrhage caused by internal carotid artery-BBAs and were treated with the endovascular patch embolization method in our center from October 2011 to March 2015. Clinical records, angiographic findings, procedural details, and follow-up results are reported in this study. Eight patients were enrolled in this study. All patients were treated with the endovascular patch embolization method. The key points of this method are step-by-step stent deployment and swaying of the microcatheter to coil the aneurysm sac and the wedge-shaped space between the stent and parent artery and, thereby, in the aneurysm sac and parent artery around the aneurysm neck. When the stent is completely deployed, an endovascular patch is formed and anchored around the neck of the BBA. The procedure was successful in all cases. No acute complications developed in any case. No rerupture or recurrence of the BBA occurred during follow-up. One patient with Hunt-Hess V subarachnoid hemorrhage died of multiple organ failure 4 months post treatment. Another patient died of intracranial infection related to the ventricle-peritoneal shunt. The remaining 6 patients had good clinical outcomes (modified Rankin Scale score of zero). Endovascular patch embolization is an improvement on stent-assisted coil embolization, which could be successfully performed only with extensive skill and patience. Endovascular patch embolization could be an effective method in BBA treatment. However, its efficacy and safety should be verified in a larger patient cohort and long-term follow-up study. Copyright © 2018. Published by Elsevier Inc.

ARC-2002-ACD02-0015-070

NASA Image and Video Library

2002-02-01

NASA Administrator Sean O'Keefe comes to Ames for employee briefing and tour. Here he welcomes JASON kids to NASA while handing out patches and pins. Tom Clausen and Donald James, Ames Education Office in background.

Experimental Evidence Shows the Importance of Behavioural Plasticity and Body Size under Competition in Waterfowl

PubMed Central

Zhang, Yong; Prins, Herbert H. T.; Versluijs, Martijn; Wessels, Rick; Cao, Lei; de Boer, Willem Frederik

2016-01-01

When differently sized species feed on the same resources, interference competition may occur, which may negatively affect their food intake rate. It is expected that competition between species also alters behaviour and feeding patch selection. To assess these changes in behaviour and patch selection, we applied an experimental approach using captive birds of three differently sized Anatidae species: wigeon (Anas penelope) (~600 g), swan goose (Anser cygnoides) (~2700 g) and bean goose (Anser fabalis) (~3200 g). We quantified the functional response for each species and then recorded their behaviour and patch selection with and without potential competitors, using different species combinations. Our results showed that all three species acquired the highest nitrogen intake at relatively tall swards (6, 9 cm) when foraging in single species flocks in the functional response experiment. Goose species were offered foraging patches differing in sward height with and without competitors, and we tested for the effect of competition on foraging behaviour. The mean percentage of time spent feeding and being vigilant did not change under competition for all species. However, all species utilized strategies that increased their peck rate on patches across different sward heights, resulting in the same instantaneous and nitrogen intake rate. Our results suggest that variation in peck rate over different swards height permits Anatidae herbivores to compensate for the loss of intake under competition, illustrating the importance of behavioural plasticity in heterogeneous environments when competing with other species for resources. PMID:27727315

Morphological and physiological responses of seagrasses (Alismatales) to grazers (Testudines: Cheloniidae) and the role of these responses as grazing patch abandonment cues.

PubMed

Lacey, Elizabeth A; Collado-Vides, Ligia; Fourqurean, James W

2014-12-01

Green sea turtles, Chelonia mydas, are grazers influencing the distribution of seagrass within shallow coastal ecosystems, yet the drivers behind C. mydas patch use within seagrass beds are largely unknown. Current theories center on food quality (nutrient content) as the plant responds to grazing disturbances; however, no study has monitored these parameters in a natural setting without grazer manipulation. To determine the morphological and physiological responses potentially influencing seagrass recovery from grazing disturbances, seagrasses were monitored for one year under three different grazing scenarios (turtle grazed, fish grazed and ungrazed) in a tropical ecosystem in Akumal Bay, Quintana Roo, Mexico. Significantly less soluble carbohydrates and increased nitrogen and phosphorus content in Thalassia testudinum were indicative of the stresses placed on seagrasses during herbivory. To determine if these physiological responses were the drivers of the heterogeneous grazing behavior by C. mydas recorded in Akumal Bay, patches were mapped and monitored over a six-month interval. The abandoned patches had the lowest standing crop rather than leaf nutrient or rhi- zome soluble carbohydrate content. This suggests a modified Giving Up Density (GUD) behavior: the critical threshold where cost of continued grazing does not provide minimum nutrients, therefore, new patches must be utilized, explains resource abandonment and mechanism behind C. mydas grazing. This study is the first to apply GUD theory, often applied in terrestrial literature, to explain marine herbivore grazing behavior.

Looking for trouble: revenge-planning and preattentive vigilance for angry facial expressions.

PubMed

Crowe, Sarah E; Wilkowski, Benjamin M

2013-08-01

Revenge-planning refers to individual differences in the tendency to actively seek out hostile confrontations with others. Building on past theory, we hypothesized that revenge-planning would be related to preattentive vigilance for angry facial expressions. By being vigilant for such expressions, individuals could more readily notice and prepare to confront social challenges. We conducted 2 studies to test this prediction. Across studies, results indicated that participants high in revenge-planning had significantly longer color-naming latencies for masked angry expressions presented in a subliminal Stroop task, regardless of whether the expression was presented inside or outside participants' attentional focus. This phenomenon was specific to revenge-planning and did not extend to the related construct of angry rumination. Such results suggest that preattentive vigilance for angry expressions supports a confrontational social style in which a person actively seeks out hostile social encounters. PsycINFO Database Record (c) 2013 APA, all rights reserved.

White clouds on Io?

NASA Astrophysics Data System (ADS)

Rogers, J. H.

1998-10-01

This paper reports rapid changes in the distribution of bright white patches in one region of Io, close to the subjovian point and the caldera Karei Patera. A stable pattern of white patches in this region was recorded by Voyager in 1979. A strikingly different pattern was shown in the first Galileo-G1 image (1996 June). However, the patterns in another Galileo-G1 and several Galileo-G2 images (1996 September) were similar although not identical to that seen by Voyager. Hubble Space Telescope images in 1994 and 1995 also resembled the Voyager pattern. The changes in the first Galileo image are not easily attributable to differences in lighting and viewing angles, and appear to be real physical changes, which occurred over a matter of days during the Galileo-G1 encounter. They also do not have the characteristics expected of surface deposits. I suggest that some of these white patches may be drifting opaque white clouds. They may be emitted from volcanic sources which have recently been reported in this area.

The Inner Disk of M31 is Full of Cold Molecular Gas

NASA Astrophysics Data System (ADS)

Allen, R. J.; Lequeux, J.; Loinard, L.

1994-12-01

The Andromeda galaxy is conspicuously devoid of the classical tracers of star formation inside a radius of about 8 kpc. This ``hole'' shows up in the distribution of HI, of HII regions, and of CO. The IRAS infrared and radio continuum also show similar ``donut''-shaped distributions, although they have additional nuclear sources. The conclusion that the inner disk of M31 contains little or no interstellar gas is, however, quite incorrect. We have carried out a sensitive CO survey with the 30m IRAM millimeter radio telescope at more than two dozen randomly-chosen points in the ``hole'' of M31, and find faint CO emission characteristic of giant molecular clouds at more than half of them, often (but not always) coincident with known dust patches. The CO is more than a factor of 10 under-luminous when compared to Galactic GMC's, a consequence of its very low excitation temperature. Estimates of the mass surface density of molecular gas can be made using the virial theorem, leading to values of about 10 solar masses per square parsec averaged over the inner disk. We conclude that THE ``HOLE'' IN M31 IS FULL OF COLD MOLECULAR GAS. The implications of this for our current views of the distribution of the ISM in galaxies will be discussed.

Low-Dose Ethanol Preconditioning Protects Against Oxygen-Glucose Deprivation/Reoxygenation-Induced Neuronal Injury By Activating Large Conductance, Ca2+-Activated K+ Channels In Vitro.

PubMed

Su, Fang; Guo, An-Chen; Li, Wei-Wei; Zhao, Yi-Long; Qu, Zheng-Yi; Wang, Yong-Jun; Wang, Qun; Zhu, Yu-Lan

2017-02-01

Increasing evidence suggests that low to moderate ethanol ingestion protects against the deleterious effects of subsequent ischemia/reperfusion; however, the underlying mechanism has not been elucidated. In the present study, we showed that expression of the neuronal large-conductance, Ca 2+ -activated K + channel (BK Ca ) α-subunit was upregulated in cultured neurons exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) compared with controls. Preconditioning with low-dose ethanol (10 mmol/L) increased cell survival rate in neurons subjected to OGD/R, attenuated the OGD/R-induced elevation of cytosolic Ca 2+ levels, and reduced the number of apoptotic neurons. Western blots revealed that ethanol preconditioning upregulated expression of the anti-apoptotic protein Bcl-2 and downregulated the pro-apoptotic protein Bax. The protective effect of ethanol preconditioning was antagonized by a BK Ca channel inhibitor, paxilline. Inside-out patches in primary neurons also demonstrated the direct activation of the BK Ca channel by 10 mmol/L ethanol. The above results indicated that low-dose ethanol preconditioning exerts its neuroprotective effects by attenuating the elevation of cytosolic Ca 2+ and preventing neuronal apoptosis, and this is mediated by BK Ca channel activation.

Experiments on vibration control of a piezoelectric laminated paraboloidal shell

NASA Astrophysics Data System (ADS)

Yue, Honghao; Lu, Yifan; Deng, Zongquan; Tzou, Hornsen

2017-01-01

A paraboloidal shell plays a key role in aerospace and optical structural systems applied to large optical reflector, communications antenna, rocket fairing, missile radome, etc. Due to the complexity of analytical procedures, an experimental study of active vibration control of a piezoelectric laminated paraboloidal shell by positive position feedback is carried out. Sixteen PVDF patches are laminated inside and outside of the shell, in which eight of them are used as sensors and eight as actuators to control the vibration of the first two natural modes. Lower natural frequencies and vibration modes of the paraboloidal shell are obtained via the frequency response function analysis by Modal VIEW software. A mathematical model of the control system is formulated by means of parameter identification. The first shell mode is controlled as well as coupled the first and second modes based on the positive position feedback (PPF) algorithm. To minimize the control energy consumption in orbit, an adaptive modal control method is developed in this study by using the PPF in laboratory experiments. The control system collects vibration signals from the piezoelectric sensors to identify location(s) of the largest vibration amplitudes and then select the best two from eight PVDF actuators to apply control forces so that the modal vibration suppression could be accomplished adaptively and effectively.

High Intracellular Chloride Slows the Decay of Glycinergic Currents

PubMed Central

Pitt, Samantha J.; Sivilotti, Lucia G.; Beato, Marco

2009-01-01

The time course of currents mediated by native and recombinant glycine receptors was examined with a combination of rapid agonist applications to outside-out patches and single-channel recording. The deactivation time constant of currents evoked by brief, saturating pulses of glycine is profoundly affected by the chloride concentration on the intracellular side of the cell membrane. Deactivation was threefold slower when intracellular chloride was increased from a low level (10 mm), similar to that observed in living mature neurons, to 131 mm (“symmetrical” chloride, often used in pipette internal solutions). Single-channel analysis revealed that high chloride has its greatest effect on the channel closing rate, slowing it by a factor of 2 compared with the value we estimated in the cell-attached mode (in which the channels are at physiological intracellular chloride concentrations). The same effect of chloride was observed when glycinergic evoked synaptic currents were recorded from juvenile rat spinal motoneurons in vitro, because the decay time constant was reduced from ∼7ms to ∼3 ms when cells were dialyzed with 10 mm chloride intracellular recording solution. Our results indicate that the time course of glycinergic synaptic inhibition in intact neurons is much faster than is estimated by measurements in symmetrical chloride and can be modulated by changes in intracellular chloride concentration in the range that can occur in physiological or pathological conditions. PMID:18987182

Chronic cranial window with access port for repeated cellular manipulations, drug application, and electrophysiology

PubMed Central

Roome, Christopher J.; Kuhn, Bernd

2014-01-01

Chronic cranial windows have been instrumental in advancing optical studies in vivo, permitting long-term, high-resolution imaging in various brain regions. However, once a window is attached it is difficult to regain access to the brain under the window for cellular manipulations. Here we describe a simple device that combines long term in vivo optical imaging with direct brain access via glass or quartz pipettes and metal, glass, or quartz electrodes for cellular manipulations like dye or drug injections and electrophysiological stimulations or recordings while keeping the craniotomy sterile. Our device comprises a regular cranial window glass coverslip with a drilled access hole later sealed with biocompatible silicone. This chronic cranial window with access port is cheap, easy to manufacture, can be mounted just as the regular chronic cranial window, and is self-sealing after retraction of the pipette or electrode. We demonstrate that multiple injections can be performed through the silicone port by repetitively bolus loading calcium sensitive dye into mouse barrel cortex and recording spontaneous cellular activity over a period of weeks. As an example to the extent of its utility for electrophysiological recording, we describe how simple removal of the silicone seal can permit patch pipette access for whole-cell patch clamp recordings in vivo. During these chronic experiments we do not observe any infections under the window or impairment of animal health. PMID:25426027

Holographic shell model: Stack data structure inside black holes?

NASA Astrophysics Data System (ADS)

Davidson, Aharon

2014-03-01

Rather than tiling the black hole horizon by Planck area patches, we suggest that bits of information inhabit, universally and holographically, the entire black core interior, a bit per a light sheet unit interval of order Planck area difference. The number of distinguishable (tagged by a binary code) configurations, counted within the context of a discrete holographic shell model, is given by the Catalan series. The area entropy formula is recovered, including Cardy's universal logarithmic correction, and the equipartition of mass per degree of freedom is proven. The black hole information storage resembles, in the count procedure, the so-called stack data structure.

Design, simulation and analysis a microstrip antenna using PU-EFB substrate

NASA Astrophysics Data System (ADS)

Mahmud, S. N. S.; Jusoh, M. A.; Jasim, S. E.; Zamani, A. H.; Abdullah, M. H.

2018-04-01

A low cost, light weight and easy to fabricate are the most important factor for future antennas. Microstrip patch antennas offer these advantages and suitable for communication and sensor application. This paper presents a design of simple microstrip patch antenna working on operating frequency of 2.4 GHz. The designed process has been carried out using MATLAB and HFSS software by entering 2.3 for the dielectric constant of PU-EFB. The results showed that high return loss, low bandwidth and good antenna radiation efficiency of which are -21.98 dB, 0.28 dB and 97.33%, respectively.

Does fragmentation of Urtica habitats affect phytophagous and predatory insects differentially?

PubMed

Zabel, Jörg; Tscharntke, Teja

1998-09-01

Effects of habitat fragmentation on the insect community of stinging nettle (Urtica dioica L.) were studied, using 32 natural nettle patches of different area and degree of isolation in an agricultural landscape. Habitat fragmentation reduced the species richness of Heteroptera, Auchenorrhyncha, and Coleoptera, and the abundance of populations. Habitat isolation and area reduction did not affect all insect species equally. Monophagous herbivores had a higher probability of absence from small patches than all (monophagous and polyphagous) herbivore species, and the percentage of monophagous herbivores increased with habitat area. Abundance and population variability of species were negatively correlated and could both be used as a predictor of the percentage of occupied habitats. Species richness of herbivores correlated (positively) with habitat area, while species richness of predators correlated (negatively) with habitat isolation. In logistic regressions, the probability of absence of monophagous herbivores from habitat patches could only be explained by habitat area (in 4 out of 10 species) and predator absence probability only by habitat isolation (in 3 out of 14 species). Presumably because of the instability of higher-trophic-level populations and dispersal limitation, predators were more affected by habitat isolation than herbivores, while they did not differ from herbivore populations with respect to abundance or variability. Thus increasing habitat connectivity in the agricultural landscape should primarily promote predator populations.

Lidocaine self-sacrificially improves the skin permeation of the acidic and poorly water-soluble drug etodolac via its transformation into an ionic liquid.

PubMed

Miwa, Yasushi; Hamamoto, Hidetoshi; Ishida, Tatsuhiro

2016-05-01

Poor transdermal penetration of active pharmaceutical ingredients (APIs) impairs both bioavailability and therapeutic benefits and is a major challenge in the development of transdermal drug delivery systems. Here, we transformed a poorly water-soluble drug, etodolac, into an ionic liquid in order to improve its hydrophobicity, hydrophilicity and skin permeability. The ionic liquid was prepared by mixing etodolac with lidocaine (1:1, mol/mol). Both the free drug and the transformed ionic liquid were characterized by differential scanning colorimetry (DSC), infrared spectroscopy (IR), and saturation concentration measurements. In addition, in vitro skin-permeation testing was carried out via an ionic liquid-containing patch (Etoreat patch). The lidocaine and etodolac in ionic liquid form led to a relatively lower melting point than either lidocaine or etodolac alone, and this improved the lipophilicity/hydrophilicity of etodolac. In vitro skin-permeation testing demonstrated that the Etoreat patch significantly increased the skin permeation of etodolac (9.3-fold) compared with an etodolac alone patch, although an Etoreat patch did not increase the skin permeation of lidocaine, which was consistent with the results when using a lidocaine alone patch. Lidocaine appeared to self-sacrificially improve the skin permeation of etodolac via its transformation into an ionic liquid. The data suggest that ionic liquids composed of approved drugs may substantially expand the formulation preparation method to meet the challenges of drugs which are characterized by poor rates of transdermal absorption. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Identifying preferred habitats of samango monkeys (Cercopithecus (nictitans) mitis erythrarchus) through patch use.

PubMed

Emerson, Sara E; Brown, Joel S

2013-11-01

To examine habitat preferences of two groups of samango monkeys (Cercopithecus (nictitans) mitis erythrarchus) in the Soutpansberg, South Africa, we used experimental food patches in fragments of tall forest and in bordering secondary growth short forest. Additionally, to test for the impacts of group cohesion and movement on habitat use, we tested for the interaction of space and time in our analyses of foraging intensity in the experimental food patches placed throughout the home ranges of the two groups. We expected the monkeys to harvest the most from patches in tall forest habitats and the least from patches in short forest. Further, because the monkeys move through their habitats in groups, we expected to see group cohesion effects illustrated by daily spatial variation in the monkeys’ use of widespread foraging grids. In the forest height experiments, the two groups differed in their foraging responses, with 8% greater foraging overall for one group. However, forest height did not significantly impact foraging in either group, meaning that, given feeding opportunities, samango monkeys are able to utilise secondary growth forest. For one group, missed opportunity costs of staying with the group appeared through the statistical interaction of day with foraging location (the monkeys did not always spread out to take advantage of all available food patches). In several subsequent experiments in widespread grids, significant daily spatial variation in foraging occurred, pointing to spatial cohesion during group movement as likely being an important predictor of habitat use. For an individual social forager, staying with the group may be more important than habitat type in driving habitat selection.

METAPOPULATION DYNAMICS AND AMPHIBIAN CONSERVATION

EPA Science Inventory

In many respects, amphibian spatial dynamics resemble classical metapopulation models, where subpopulations in breeding ponds blink in and out of existance and where extinction and colonization rates are functions of pond spatial arrangement. This "ponds-as-patches" view of amphi...

Matching Patterns of Light

NASA Image and Video Library

2014-11-06

These images from the Cosmic Infrared Background Experiment, or CIBER, show large patches of the sky at two different infrared wavelengths 1.1 microns and 1.6 microns after all known galaxies have been subtracted out and the images smoothed.

In Vivo Evaluation of Wearable Head Impact Sensors.

PubMed

Wu, Lyndia C; Nangia, Vaibhav; Bui, Kevin; Hammoor, Bradley; Kurt, Mehmet; Hernandez, Fidel; Kuo, Calvin; Camarillo, David B

2016-04-01

Inertial sensors are commonly used to measure human head motion. Some sensors have been tested with dummy or cadaver experiments with mixed results, and methods to evaluate sensors in vivo are lacking. Here we present an in vivo method using high speed video to test teeth-mounted (mouthguard), soft tissue-mounted (skin patch), and headgear-mounted (skull cap) sensors during 6-13 g sagittal soccer head impacts. Sensor coupling to the skull was quantified by displacement from an ear-canal reference. Mouthguard displacements were within video measurement error (<1 mm), while the skin patch and skull cap displaced up to 4 and 13 mm from the ear-canal reference, respectively. We used the mouthguard, which had the least displacement from skull, as the reference to assess 6-degree-of-freedom skin patch and skull cap measurements. Linear and rotational acceleration magnitudes were over-predicted by both the skin patch (with 120% NRMS error for a(mag), 290% for α(mag)) and the skull cap (320% NRMS error for a(mag), 500% for α(mag)). Such over-predictions were largely due to out-of-plane motion. To model sensor error, we found that in-plane skin patch linear acceleration in the anterior-posterior direction could be modeled by an underdamped viscoelastic system. In summary, the mouthguard showed tighter skull coupling than the other sensor mounting approaches. Furthermore, the in vivo methods presented are valuable for investigating skull acceleration sensor technologies.