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Sample records for hyalophora cecropia stimulation

  1. Vegetative propagation of Cecropia obtusifolia (Cecropiaceae

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    Louis M. LaPierre

    2001-12-01

    Full Text Available Cecropia is a relatively well-known and well-studied genus in the Neotropics. Methods for the successful propagation of C. obtusifolia Bertoloni. 1840 from cuttings and air layering are described, and the results of an experiment to test the effect of two auxins, naphthalene acetic acid (NAA and indole butyric acid (IBA, on adventitious root production in cuttings are presented. In general. C. obtusifolia cuttings respond well to adventitious root production (58.3 % of cuttings survived to root, but air layering was the better method (93 % of cuttings survived to root. The concentration of auxins used resulted in an overall significantly lower quality of roots produced compared with cuttings without auxin treatment. Future experiments using Cecropia could benefit from the use of isogenic plants produced by vegetative propagationCecropia es un género bien conocido y bien estudiado en los Neotrópicos. Se discuten métodos exitosos para la propagación de C. obtusifolia Bertoloni, 1840 de fragmentos de troncos y acodos aéreos. A continuación se presentan los resultados de un experimento para examinar los efectos de dos tipos de hormonas (NAA e IBA en la producción de raíces adventicias en fragmentos de troncos. En general, los fragmentos de C. abtusifalia responden bien en la producción de raíces adventicias (y sobreviven al azar 58.3% de los cortes, pero el método de acodos aéreos funcionó mejor (sobreviven al azar 93 %. El uso de hormonas resultó en raíces de baja calidad en comparación con cortes sin hormonas. Experimentos en el futuro que usan Cecropia pueden beneficiar al usar plantas isogénicas producidas por propagación vegetativa

  2. Distributional patterns of cecropia (Cecropiaceae: a panbiogeographic analysis

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    Franco Rosselli Pilar

    1997-06-01

    Full Text Available A panbiogeographic analysis of the distributional patterns of 60 species of Cecropia was carried out. Based on the distributional ranges of 36 species, we found eight generalized tracks for Cecropia species. whereas distributional patterns of 24 species were uninformative for the analysis. The major concentration of species of Cecropia is in the Neotropical Andean region. where there are three generalized tracks and two nodes. The northern Andes in Colombia and Ecuador are richer than the Central Andes in Perú. they contain two generalized tracks; one to the west and another to the east, formed by individual tracks of eight species each. There are four generalized tracks outside the Andean region: two in the Amazonian region in Guayana-Pará and in Manaus. one in Roraima. one in Serra do Mar in the Atlantic forest of Brazil and one in Central America. Speciation in Cecropia may be related to the Andean first uplift.Con base en la distribución de 60 especies del género Cecropia, se hizo un análisis panbiogeográfico. Se construyeron 8 trazos generalizados con base en el patrón de distribución de 36 especies; la distribución de las demás especies no aportaba información para la definición de los trazos. La región andina tiene la mayor concentración de especies de Cecropia representada por la presencia de tres trazos generalizados y dos nodos; los dos trazos con mayor número de especies se localizan en su parte norte, en Colombia y Ecuador y el otro en los Andes centrales en Perú. Se encontraron además, cuatro trazos extrandinos: dos en la región amazónica, en Pará-Guayana y en Manaus, uno en Roraima, uno en Serra do Mar en la Selva Atlánfíca del Brasil y uno en Centro América. La especiación en Cecropia parece estar relacionada con el primer levantamiento de los Andes.

  3. The status of Cecropia (Urticaceae) introductions in Malesia: addressing the confusion

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    Conn, B.J.; Hadiah, J.T.; Webber, B.L.

    2012-01-01

    As part of the great global movement of plants in the 18th and 19th centuries, many valuable and commercial plants were sent from the Neotropics to Europe as seeds or as live specimens. Cecropia (Urticaceae) was in cultivation in England in 1789, yet species delimitation was not well-understood unti

  4. SOME STRENGTH AND RELATED PROPERTIES OF YAGRUMO HEMBRA (CECROPIA PELTATA) FROM PUERTO RICO.

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    Evaluations of several mechanical and physical properties were conducted on specimens from five yagrumo hembra (Cecropia peltata) trees from Puerto...Dense yagrumo hembra resembles North American black cottonwood in both specific gravity and mechanical properties. Total shrinkage from green to the

  5. Life history and environment of Cecropia latiloba in Amazonian floodplains

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    Pia Parolin

    2002-06-01

    Full Text Available Cecropia latiloba can be considered to be one of the most efficient colonizers of open areas in the nutrient-rich whitewater floodplains of the Amazon river. Its main strategy to be successful is the high tolerance towards waterlogging and submergence, and the fast vertical growth and reiteration capacity. This, and the tolerance of high irradiation and sediment deposition allow C. latiloba to form large monospecific stands on open sites, and thus the first closed canopy which represents the initial phase of a successional sequence which leads to highly diverse forests. This tree is extremely well adapted to the adverse growth conditions in Amazonian floodplains with prolongued periods of flooding and seedling submergence. The species occurs on the lowest levels in the flooding gradient. Although it belongs to the most often cited species under aspects of taxonomy, species distribution and general descriptions of the ecosystem, little has been published about its ecology. In the present paper the ecological, physiological and phenological characteristics of C. latiloba are described. It is an evergreen species which constantly produces new leaves. With flooding, leaf production is reduced but new leaves are flushed also with prolongued flooding. The peak of flowering and fruiting are in the flooded period. When mature, the fruits are dispersed mainly by water and fish. Seed germination occurs, without dormancy, within 5-13 days after water retreat. In the 7 months before the first flooded period seedlings reach 1 m of height, and height growth increases until a height of 15-20 m is achieved. Photosynthetic assimilation is high, with values of up to 21 mmol CO2m-2s-1 . C. latiloba is a very flood tolerant species, and waterlogged seedlings continuously produce new leaves and adventitiuos rootsCecropia latiloba puede ser considerada una de las especies colonizadoras más eficientes de áreas abiertas en las llanuras inundadas de agua dulce, rica

  6. The Effect of Symbiotic Ant Colonies on Plant Growth: A Test Using an Azteca-Cecropia System: e0120351

    National Research Council Canada - National Science Library

    Oliveira, Karla N; Coley, Phyllis D; Kursar, Thomas A; Kaminski, Lucas A; Moreira, Marcelo Z; Campos, Ricardo I

    2015-01-01

    .... In the field, we measured the growth of Cecropia glaziovii saplings and compared individuals that were naturally colonized by Azteca muelleri ants with uncolonized plants in different seasons (wet and dry...

  7. Seasonal variations in the amount of isoorientin and isovitexin in cecropia glaziovii sneth. leaves over a two-year period

    OpenAIRE

    Costa, Geison; Caroline F. Ortmann; Eloir P. Schenkel; Reginatto,Flávio H.

    2014-01-01

    Cecropia glaziovii Sneth (Urticaceae) is a common tree from Southeast and South of Brazil, being widely used in traditional medicine to treat heart and respiratory conditions. C-glycosylflavonoids have being described as the major compounds for this genus, however, no seasonality studies of individual flavonoids was conducted for any Cecropia specie. In this work, the content of isoorientin and isovitexin in aqueous extract from the leaves of C glaziovii during a two-year period was determine...

  8. An HPLC-DAD method to quantification of main phenolic compounds from leaves of Cecropia Species

    OpenAIRE

    Geison M. Costa; Caroline F. Ortmann; Eloir P. Schenkel; Reginatto,Flávio H.

    2011-01-01

    An efficient and reproducible HPLC-DAD method was developed and validated for the simultaneous quantification of major compounds (chlorogenic acid, isoorientin, orientin and isovitexin) present in the leaves of two Cecropia species, C. glaziovii and C. pachystachya. From the leaves of C. glaziovii and C. pachystachya were isolated the C-glycosylflavones isoorientin and isovitexin and identified on both species chlorogenic acid (3-O-caffeoylquinic acid) and the O-glycosylflavonol isoquercitrin...

  9. Remote Sensing observations of Cecropia communities along Amazonian rivers: Mapping and monitoring habitat dynamics with time series datasets

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    Quinteros Casaverde, N. L.; McDonald, K.

    2016-12-01

    Riverine habitats host more than 14% of non-aquatic birds in the Amazon basin, some of them considered vulnerable by the UICN due to habitat destruction. Plant species of the genus Cecropia are known for being a late pioneer species in these riverine habitats creating monospecific stands along the Amazonian rivers. Cecropia biomes are thought to have significant impacts on the avifauna communities and their diversity. Nowadays, these habitats are threatened by the on-going development in the Amazonian countries. There are plans to build hydroelectric facilities, damming important tributaries of the Amazon river. Such large scale land cover change threatens Cecropia communities and the habitats they support and associated biodiversity. Thus, it is imperative to understand the fragility of these ecosystems, their extent and spatial distribution, and seasonal influences to their environments. We employ multiple sources of remote sensing data to assess the ability to use high resolution imagery to map Cecropia communities and multi-temporal observations to assess their seasonal dynamics. This research aims to facilitate the understanding of these communities through time series analyses using remote sensing products such as high resolution images from Synthetic Aperture Radar (SAR) and Landsat to identify the Cecropia stands along the rivers and lower resolution products such as satellite-borne radiometers and scatterometers to assess seasonality. Our goal is to employ combined remote sensing data sources at map and monitor these important habitats.

  10. Myxomycetes occurring on Cecropia adenopus (Cecropiaceae in fragments of Atlantic Rainforest Myxomycetes ocorrentes em Cecropia adenopus (Cecropiaceae em fragmentos de Floresta Atlântica

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    Andrea Carla Caldas Bezerra

    2011-03-01

    Full Text Available Cecropia adenopus (Ambay pumpwood is a frequent native species on the edges of woods and clearings and is considered a pioneer species in re-colonized areas. Despite its distribution from Mexico to Argentina, this substrate has never been examined in detail regarding the presence of Myxomycetes. In the present study, the myxobiota associated with leaf debris of C. adenopus was investigated in two Atlantic Rainforest conservation units located in the Brazilian state of Rio Grande do Norte. Five specimens and one plasmodium were obtained directly from the field and 87 were developed in 43.7% of 200 moist-chamber cultures set up separately with blades and petioles. Fifteen species were identified and illustrated. The two predominant groups were representatives of Trichiales and Physarales. Didymium columella-cavum was recorded for the second time in Brazil and in the world.Cecropia adenopus (embaúba é uma espécie nativa, frequente em bordas de matas e clareiras e tida como espécie pioneira em áreas recolonizadas. Apesar de ocorrer desde o México até a Argentina este substrato nunca tinha sido examinado com detalhe quanto à presença de Myxomycetes. No presente estudo, a mixobiota associada a folhas mortas de C. adenopus foi investigada em duas Unidades de Conservação da Floresta Atlântica, situadas no estado do Rio Grande do Norte. Cinco espécimes e um plasmódio foram obtidos diretamente no campo e 87 desenvolveram-se em 43,7% de 200 câmaras-úmidas, montadas com lâminas foliares e pecíolos separadamente. Quinze espécies de Myxomycetes foram identificadas e ilustradas. Os dois grupos predominantes pertencem às ordens Trichiales e Physarales. Didymium columella-cavum foi encontrado pela segunda vez no Brasil e no mundo.

  11. Effects of light and temperature on seed germination in Cecropia hololeuca Miq. (Cecropiaceae

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    Godoi Simone

    2004-01-01

    Full Text Available Seeds of Cecropia hololeuca were submitted to regimes of constant and alternating temperatures, associated with photoperiods of white light, "shade light" and continuous darkness under controlled conditions in laboratory. Seeds did not germinate at constant temperatures of 10°C to 20°C and above 35°C. Seeds only germinated in the darkness when the temperature was alternated. "Shade light" inhibited germination. We concluded that the regime of alternating temperatures suppressed the light effects on seed germination of this species.

  12. Continental-scale patterns of Cecropia reproductive phenology: evidence from herbarium specimens.

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    Zalamea, Paul-Camilo; Munoz, François; Stevenson, Pablo R; Paine, C E Timothy; Sarmiento, Carolina; Sabatier, Daniel; Heuret, Patrick

    2011-08-22

    Plant phenology is concerned with the timing of recurring biological events. Though phenology has traditionally been studied using intensive surveys of a local flora, results from such surveys are difficult to generalize to broader spatial scales. In this study, contrastingly, we assembled a continental-scale dataset of herbarium specimens for the emblematic genus of Neotropical pioneer trees, Cecropia, and applied Fourier spectral and cospectral analyses to investigate the reproductive phenology of 35 species. We detected significant annual, sub-annual and continuous patterns, and discuss the variation in patterns within and among climatic regions. Although previous studies have suggested that pioneer species generally produce flowers continually throughout the year, we found that at least one third of Cecropia species are characterized by clear annual flowering behaviour. We further investigated the relationships between phenology and climate seasonality, showing strong associations between phenology and seasonal variations in precipitation and temperature. We also verified our results against field survey data gathered from the literature. Our findings indicate that herbarium material is a reliable resource for use in the investigation of large-scale patterns in plant phenology, offering a promising complement to local intensive field studies.

  13. High-speed countercurrent chromatography as a valuable tool to isolate C-glycosylflavones from Cecropia lyratiloba Miquel.

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    Oliveira, R R; Moraes, M C C; Castilho, R O; Valente, A P; Carauta, J P P; Lopes, D; Kaplan, M A C

    2003-01-01

    A new apigeninglycoside, apigenin 6-C-galactosyl-6"-O-beta-galactopyranoside (1), isoorientin, and a mixture of orientin and isovitexin were isolated from leaves of Cecropia lyratiloba by high-speed countercurrent chromatography using a solvent system containing ethyl acetate, butanol, methanol and water. The structural elucidation of 1 was based on NMR spectroscopy.

  14. The genus Cecropia: a biological clock to estimate the age of recently disturbed areas in the Neotropics.

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    Paul-Camilo Zalamea

    Full Text Available Forest successional processes following disturbance take decades to play out, even in tropical forests. Nonetheless, records of vegetation change in this ecosystem are scarce, increasing the importance of the chronosequence approach to study forest recovery. However, this approach requires accurate dating of secondary forests, which until now was a difficult and/or expensive task. Cecropia is a widespread and abundant pioneer tree genus of the Neotropics. Here we propose and validate a rapid and straightforward method to estimate the age of secondary forest patches based on morphological observations of Cecropia trees. We found that Cecropia-inferred ages were highly correlated with known ages of the forest. We also demonstrate that Cecropia can be used to accurately date disturbances and propose twenty-one species distributed all over the geographical range of the genus as potential secondary forest chronometer species. Our method is limited in applicability by the maximal longevity of Cecropia individuals. Although the oldest chronosequence used in this study was 20 years old, we argue that at least for the first four decades after disturbance, the method described in this study provides very accurate estimations of secondary forest ages. The age of pioneer trees provides not only information needed to calculate the recovery of carbon stocks that would help to improve forest management, but also provides information needed to characterize the initial floristic composition and the rates of species remigration into secondary forest. Our contribution shows how successional studies can be reliably and inexpensively extended without the need to obtain forest ages based on expensive or potentially inaccurate data across the Neotropics.

  15. Estudo comparativo das madeiras de cecropia palmata (imbaúba) e eucalyptus grandis para produção de celulose e papel

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    Pupo, Camyla Heckler [UNESP

    2015-01-01

    Much remains to be studied on the Amazonian species, among many varieties can be species with excellent characteristics for the production of pulp and paper that have not yet had their technological potential revealed. The Cecropia palmata is native to the Amazon, which initially presents excellent characteristics for pulp production. Therefore, this study aimed to study the quality of the native wood Cecropia palmata Amazon for the production of pulp and paper, through a comparative study wi...

  16. An HPLC-DAD method to quantification of main phenolic compounds from leaves of Cecropia species

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Geison M.; Ortmann, Caroline F.; Schenkel, Eloir P.; Reginatto, Flavio H., E-mail: freginatto@hotmail.co [Universidade Federal de Santa Catarina (UFSC), Florianopolis (Brazil). Centro de Ciencias da Saude. Dept. de Ciencias Farmaceuticas

    2011-07-01

    An efficient and reproducible HPLC-DAD method was developed and validated for the simultaneous quantification of major compounds (chlorogenic acid, isoorientin, orientin and isovitexin) present in the leaves of two Cecropia species, C. glaziovii and C. pachystachya. From the leaves of C. glaziovii and C. pachystachya were isolated the C-glycosylflavones isoorientin and isovitexin and identified on both species chlorogenic acid (3-O-caffeoylquinic acid) and the O-glycosylflavonol isoquercitrin. The C-glycosylflavone orientin was isolated only from C. pachystachya. Chlorogenic acid was the major compound in both species (11.1 mg g{sup -1} of extract of C. glaziovii and 27.2 mg g{sup -1} of extract of C. pachystachya) and for the flavonoids quantified, isovitexin was the main C-glycosylflavonoid for C. glaziovii (4.6 mg g{sup -1} of extract) and isoorientin the main one for C. pachystachya (17.3 mg g{sup -1} of extract). (author)

  17. In vivo potential hypoglycemic and in vitro vasorelaxant effects of Cecropia glazioviistandardized extracts

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    Daniela Paula Arend

    2015-10-01

    Full Text Available ABSTRACTThe aim of this study is to investigate the effect of Cecropia glaziovii Snethl, Urticaceae, extracts on the oral glucose tolerance curve, on glycemia in alloxan-induced diabetic rats and vasorelaxant effect after the extraction process, and to standardize the extractive solutions. The effects of the process variables and their interactions were calculated in relation to dry residue, pH, total phenolic results and chemical marker content. Furthermore, the effect of the extracts (400 mg/kg, chlorogenic (2 or 15 mg/kg and caffeic acids (2 mg/kg were investigated on the oral glucose tolerance curve and on glycemia in alloxan-induced diabetic rats. Oral administration of ethanol extracts 4d20 and 8d20 significantly improved glucose tolerance in the hyperglycemic rats. Chlorogenic and caffeic acids, as well as the association of the compounds were able to significantly reduce glycemia after oral gavage treatments. On the other hand, the aqueous extracts did not alter the glycemia. The aqueous extracts (8020 and 9030 and only the higher dose of chlorogenic acid presented a significant effect on serum glucose lowering in diabetic rats. Additionally, the IC50 reveals that the ethanol extracts presented more potent vasodilator effects than the aqueous extracts in aortic rings. This study shows that C. glazioviistandardized extracts exhibits antihyperglycemic action, is able to improve glucose tolerance and has a potent vascular relaxing effect. These results are probably linked to concentrations of the main phenolic compounds of the extracts.

  18. Differences on post-fire regeneration of the pioneer trees Cecropia glazioui and Trema micrantha in a lowland Brazilian Atlantic Forest

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    Dalva M Silva-Matos

    2005-06-01

    Full Text Available A study of natural post-fire succession was carried out in a disturbed vegetation around fragments of the Atlantic Rain Forest (National Biological Reserve of Poço das Antas (22 °30 ’-22 °33 ’S,42 °15 ’-42 °19 ’W, Rio de Janeiro State.All the pre-fire individuals of Cecropia and Trema in the area were numbered with plastic labels.In order to check for the presence of new sprouts and mortality,two other censuses were carried out,at 3 and 12 months after the fire.The dominant species were:Pteridium aquilinum,Panicum maximum,Trema micrantha and Cecropia glazioui. Few days after the passage of fire, grasses and ferns spread their area,while the stands of Trema and Cecropia were completely burned. Most of individuals of Cecropia produced some sprouts while most of individuals of Trema died.However,a great number of seedlings of Trema were recruited while only one single seedling of Cecropia were observed during a period of one year.Most of these seedlings died through the year while the sprouts were already reproducing.The uses of Cecropia in places where fire is recurrent could be more appropriate because of its higher chance of survival and faster recovering ability after fire.Rev.Biol.Trop.53(1-2:1-4.Epub 2005 Jun 24Se realizó un estudio sobre la sucesión natural después del fuego en una vegetación alrededor de fragmentos de la selva lluviosa atlántica (Reserva Biológica Nacional de Poço das Antas (22° 30 ’-22° 33 ’ S, 42° 15’- 42° 19’ W, Estado de Río de Janeiro.Todos los individuos de Cecropia y Trema previos del fuego en el área fueron numerados con marcas plásticas. Se realizaron otros dos censos, 3 y 12 meses después del fuego con el objetivo de detectar mortalidad y buscar la presencia de nuevos brotes. Las especies dominantes fueron: Pteridium aquilinum, Panicum maximum, Trema micrantha y Cecropia glazioui. Pocos días después del paso del fuego,los pastos y helechos se dispersaron por el área, mientras

  19. Does exogenic food benefit both partners in an ant-plant mutualism? The case of Cecropia obtusa and its guest Azteca plant-ants.

    Science.gov (United States)

    Dejean, Alain; Petitclerc, Frédéric; Roux, Olivier; Orivel, Jérôme; Leroy, Céline

    2012-03-01

    In the mutualisms involving the myrmecophyte Cecropia obtusa and Azteca ovaticeps or A. alfari, both predatory, the ants defend their host trees from enemies and provide them with nutrients (myrmecotrophy). A. ovaticeps provisioned with prey and then (15)N-enriched food produced more individuals than did control colonies (not artificially provisioned). This was not true for A. alfari colonies, possibly due to differences in the degree of maturity of the colonies for the chosen range of host tree sizes (less than 3m in height). Myrmecotrophy was demonstrated for both Azteca species as provisioning the ants with (15)N-enriched food translated into higher δ(15)N values in host plant tissues, indicating that nitrogen passed from the food to the plant. Thus, the predatory activity of their guest ants benefits the Cecropia trees not only because the ants protect them from defoliators since most prey are phytophagous insects but also because the plant absorbs nutrients.

  20. MALDI-TOF MS Analysis of Proanthocyanidins in Two Lowland Tropical Forest Species of Cecropia: A First Look at Their Chemical Structures

    OpenAIRE

    Alex Van Huynh; John M. Bevington

    2014-01-01

    The structural chemistry of proanthocyanidin molecules has been investigated in temperate zone plants, but few studies have been done with plants of the Amazonian lowland tropical wet forests where herbivore pressure is more extensive and diverse. Using MALDI-TOF mass spectrometry, we report unique properties of the proanthocyanidin structural chemistry in two neotropical Cecropia species, C. polystachya, a myrmecophyte with mutualistic ants, and C. sciadophylla, a non-myrmecophyte lacking mu...

  1. Interação planta-inseto: Aspectos biológicos e ecológicos do mutualismo Cecropia-Azteca

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    2015-08-01

    Abstract. A well-known association is the mutualism between plants is between plant species of the genus Cecropia and ants, mostly belonging to the genus Azteca. In this association, the ants nest in domatia present in the hollow trunk of this myrmecophytes and feed on food bodies provided by the plant, known as mullerian bodies. In return, the ants protect the host plant against herbivore attacks and invasion by vines, and nourish it through waste laid in the trunk. However, the effectiveness of this association may vary with several factors, such as the associated ant species and the habitat type of the myrmecophyte. About 10% of Cecropia species lost their attractive characteristics, such as species living in high altitude and inhabit islands. Aspects like associated ant richness and molecular studies show that the colonization of these plants by ants occurred several times and independently by different genera. The selection pressure exerted by some species of ants may have been one of the decisive factors for the development of attractive traits for ants in Cecropia. With the evolution of these features ants might become an effective partner of the plant, facilitating the co-evolution of specific interactions.

  2. MALDI-TOF MS Analysis of Proanthocyanidins in Two Lowland Tropical Forest Species of Cecropia: A First Look at Their Chemical Structures

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    Alex Van Huynh

    2014-09-01

    Full Text Available The structural chemistry of proanthocyanidin molecules has been investigated in temperate zone plants, but few studies have been done with plants of the Amazonian lowland tropical wet forests where herbivore pressure is more extensive and diverse. Using MALDI-TOF mass spectrometry, we report unique properties of the proanthocyanidin structural chemistry in two neotropical Cecropia species, C. polystachya, a myrmecophyte with mutualistic ants, and C. sciadophylla, a non-myrmecophyte lacking mutualistic ants. Our preliminary data suggests the presence of reportedly uncommon propelargonidin subunits in a majority of proanthocyanidin oligomers. The presence of 3-O-gallate proanthocyanidin monomers was also detected in the mass spectra of both species. Unlike other studies that have examined species growing at higher latitudes, oligomers composed of procyanidin, propelargonidin, and their 3-O-gallates were present in both Cecropia species while the presence of oligomers containing prodelphinidin units were absent or at lower levels. These distinctive features may suggest that proanthocyanidins in some tropical plant species may be an untapped source of proanthocyanidin structural complexity that warrants further investigation. Several differences between spectra of the two Cecropia species could also point to the presence of anti-herbivore defense tradeoffs between chemical defense quality and biotic defense between the two species.

  3. Herança e desequilíbrio de ligação em sete locos isoenzimáticos de Cecropia pachystachya. Inheritance and linkage disequilibrium in sevem isozymes loci of Cecropia pachystachya.

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    Luciano Arruda RIBAS

    2004-12-01

    Full Text Available Seis sistemas enzimáticos (ACP,G6PDH, IDH, PGI, PGM e SKDH, codificandosete locos polimórficos (Acp-3, G6pdh-1, Idh-1,Pgi-2, Pgm-1, Pgm-2 e Skdh-1, foram investigadospara a herança e desequilíbrio de ligação emCecropia pachystachya Trec. A herança mendelianafoi confirmada para todos os locos avaliados.Desvios significativos da razão de segregaçãoesperada 1:1 foram detectados apenas em umaprogênies de árvore heterozigótica. O desequilíbriode ligação foi examinado para 21 pares de locosisoenzimáticos, não sendo detectados desequilíbriosentre nenhum deles e, assim, estes podem serutilizados em subseqüentes estudos do sistemade reprodução, diversidade e estrutura genética deC. pachystachya.

  4. Clinical trial of Cecropia obtusifolia and Marrubium vulgare leaf extracts on blood glucose and serum lipids in type 2 diabetics.

    Science.gov (United States)

    Herrera-Arellano, A; Aguilar-Santamaría, L; García-Hernández, B; Nicasio-Torres, P; Tortoriello, J

    2004-11-01

    Cecropia obtusifolia and Marrubium vulgare have been widely used in Mexican traditional medicine for the control of type 2 diabetes. In order to evaluate the clinical effect produced by the aqueous extract from these species on type 2 non-controlled diabetes mellitus, a total of 43 outpatients were included. Based on the European NIDDM (policy group) criteria, only patients with poor response to the conventional treatment were selected. All patients maintained their medical treatment and also received a prepared infusion of the dry leaves of the plant treatment for 21 days. In a double-blind manner, the patients were randomly grouped as follows: 22 patients were treated with C. obtusifolia and 21 with M. vulgare. The fasting blood glucose values were reduced by 15.25% on patients treated with C. obtusifolia, while cholesterol and triglycerides were decreased by 14.62% and 42.0%, respectively (ANOVA pvulgare, the plasma glucose level was reduced by 0.64% and cholesterol and triglycerides by 4.16% and 5.78%, respectively. When the results were compared between groups, significant differences in glucose and cholesterol diminution were found. The obtained results showed that the infusion prepared with the leaves of C. obtusifolia (containing 2.99+/-0.14mg of chlorogenic acid/g of dried plant) produced beneficial effects on carbohydrate and lipid metabolisms when it was administered as an adjunct on patients with type 2 diabetes with poor response to conventional medical treatment.

  5. Cecropia pachystachya: A Species with Expressive In Vivo Topical Anti-Inflammatory and In Vitro Antioxidant Effects

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    Natália Ramos Pacheco

    2014-01-01

    Full Text Available Cecropia pachystachya is a species traditionally used in Brazil to treat inflammation. This work aims to evaluate the topical anti-inflammatory and antioxidant activities of the methanolic extract of C. pachystachya (CPM and to perform its chemical fingerprint by HPLC-DAD. The topical anti-inflammatory activity was evaluated using the mouse models of acute ear inflammation induced by croton oil, arachidonic acid, capsaicin, EPP, phenol, and chronic inflammation induced by multiple application of croton oil. The in vitro antioxidant effect of CPM was investigated using DPPH, reducing power, β-carotene bleaching, and TBARS assays. HPLC analysis was performed to quantify the antioxidant phenolics orientin, isoorientin, and chlorogenic acid previously identified in CPM. CPM exhibited significant anti-inflammatory effect in the acute models, in some cases comparable to the reference drugs. Histopathological analysis showed a moderate chronic skin anti-inflammatory effect with decrease in vasodilation, edema, cell infiltration, and epidermal hyperproliferation. It also showed strong in vitro antioxidant activity. The contents of orientin, isoorientin, and chlorogenic acid were 66.5 ± 1.8, 118.8 ± 0.7, and 5.4 ± 0.2 µg/mg extract, respectively. The topical anti-inflammatory activity of CPM could be based on its antioxidant properties, although other effects are probably involved, including COX inhibition and other mechanisms.

  6. Cecropia pachystachya: a species with expressive in vivo topical anti-inflammatory and in vitro antioxidant effects.

    Science.gov (United States)

    Pacheco, Natália Ramos; Pinto, Nícolas de Castro Campos; da Silva, Josiane Mello; Mendes, Renata de Freitas; da Costa, Juliana de Carvalho; Aragão, Danielle Maria de Oliveira; Castañon, Maria Christina Marques Nogueira; Scio, Elita

    2014-01-01

    Cecropia pachystachya is a species traditionally used in Brazil to treat inflammation. This work aims to evaluate the topical anti-inflammatory and antioxidant activities of the methanolic extract of C. pachystachya (CPM) and to perform its chemical fingerprint by HPLC-DAD. The topical anti-inflammatory activity was evaluated using the mouse models of acute ear inflammation induced by croton oil, arachidonic acid, capsaicin, EPP, phenol, and chronic inflammation induced by multiple application of croton oil. The in vitro antioxidant effect of CPM was investigated using DPPH, reducing power, β -carotene bleaching, and TBARS assays. HPLC analysis was performed to quantify the antioxidant phenolics orientin, isoorientin, and chlorogenic acid previously identified in CPM. CPM exhibited significant anti-inflammatory effect in the acute models, in some cases comparable to the reference drugs. Histopathological analysis showed a moderate chronic skin anti-inflammatory effect with decrease in vasodilation, edema, cell infiltration, and epidermal hyperproliferation. It also showed strong in vitro antioxidant activity. The contents of orientin, isoorientin, and chlorogenic acid were 66.5 ± 1.8, 118.8 ± 0.7, and 5.4 ± 0.2 µg/mg extract, respectively. The topical anti-inflammatory activity of CPM could be based on its antioxidant properties, although other effects are probably involved, including COX inhibition and other mechanisms.

  7. MORFOLOGÍA DE LOS FRUTIOLOS DE CECROPIA (CECROPIACEAE DEL PACÍFICO COLOMBIANO Y SU VALOR TAXONÓMICO EN EL ESTUDIO DE DIETAS DE MURCIÉLAGOS

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    Linares Edgar

    2010-12-01

    Full Text Available La textura, junto con la forma y el color (no siempre de fácil interpretación por el ojohumano de los frutiolos son caracteres importantes en la delimitación de las especiesde Cecropia del Pacífi co Colombiano estudiadas en esta investigación. La textura dela superfi cie es el carácter más importante, ya que permite separar dos conjuntos deespecies: textura lisa característica de Cecropia bullata, C. membranacea, C. longipes,C. obtusifolia y textura ampollosa o tuberculada de C. angustifolia, C. hispidissima,C. insignis, C. peltata, C. reticulata, C. virgusa. En este grupo se pueden segregartres subgrupos:débilmente ampollosa (C. reticulata, C. virgusa, ampollosa (C.hispidissima, C. insignis, C. peltata y tuberculada (C. angustifolia. La forma y elcolor son caracteres de menor peso que la textura. A partir de la forma se pudieronorganizar los frutiolos en: ovoides (Cecropia insignis, C. reticulata; ovoideo lanceolados(C. angustifolia, C. bullata, C. virgusa; anchamente ovoides (C. longipes, C.obtusifolia; elipsoides (C. peltata, anchamente elipsoides (C. membranacea yglobosos (C. hispidissima. El color de los frutiolos es más bien constante de acuerdocon la similitud encontrada en los frutiolos de especímenes depositados en lascolecciones del Herbario Nacional Colombiano (COL y en los que se encontraronen los contenidos estomacales de los murciélagos. Los tonos pardos (pardo claros,pardo rojizos, pardo oscuros predominaron, y en un solo caso el negro con un tonorojo central (C. obtusifolia. Las especies de Cecropia y sus respectivos consumidoresfueron: Cecropia angustifolia (consumida por Artibeus jamaicensis, Cecropia peltata(encontrada en los contenidos estomacales y heces de Artibeus jamaicensis, Carolliacastanea y Carollia perspicillata, Cecropia membranacea (consumida por Artibeuslituratus, Platyrrhinus helleri, Carollia castanea y Artibeus jamaicensis y Cecropiaobtusifolia (presente en los contenidos estomacales y heces de

  8. The effect of symbiotic ant colonies on plant growth: a test using an Azteca-Cecropia system.

    Science.gov (United States)

    Oliveira, Karla N; Coley, Phyllis D; Kursar, Thomas A; Kaminski, Lucas A; Moreira, Marcelo Z; Campos, Ricardo I

    2015-01-01

    In studies of ant-plant mutualisms, the role that ants play in increasing the growth rates of their plant partners is potentially a key beneficial service. In the field, we measured the growth of Cecropia glaziovii saplings and compared individuals that were naturally colonized by Azteca muelleri ants with uncolonized plants in different seasons (wet and dry). We also measured light availability as well as attributes that could be influenced by the presence of Azteca colonies, such as herbivory, leaf nutrients (total nitrogen and δ(15)N), and investments in defense (total phenolics and leaf mass per area). We found that colonized plants grew faster than uncolonized plants and experienced a lower level of herbivory in both the wet and dry seasons. Colonized plants had higher nitrogen content than uncolonized plants, although the δ(15)N, light environment, total phenolics and leaf mass per area, did not differ between colonized and uncolonized plants. Since colonized and uncolonized plants did not differ in the direct defenses that we evaluated, yet herbivory was lower in colonized plants, we conclude that biotic defenses were the most effective protection against herbivores in our system. This result supports the hypothesis that protection provided by ants is an important factor promoting plant growth. Since C. glaziovii is widely distributed among a variety of forests and ecotones, and since we demonstrated a strong relationship with their ant partners, this system can be useful for comparative studies of ant-plant interactions in different habitats. Also, given this study was carried out near the transition to the subtropics, these results help generalize the geographic distribution of this mutualism and may shed light on the persistence of the interactions in the face of climate change.

  9. The effect of symbiotic ant colonies on plant growth: a test using an Azteca-Cecropia system.

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    Karla N Oliveira

    Full Text Available In studies of ant-plant mutualisms, the role that ants play in increasing the growth rates of their plant partners is potentially a key beneficial service. In the field, we measured the growth of Cecropia glaziovii saplings and compared individuals that were naturally colonized by Azteca muelleri ants with uncolonized plants in different seasons (wet and dry. We also measured light availability as well as attributes that could be influenced by the presence of Azteca colonies, such as herbivory, leaf nutrients (total nitrogen and δ(15N, and investments in defense (total phenolics and leaf mass per area. We found that colonized plants grew faster than uncolonized plants and experienced a lower level of herbivory in both the wet and dry seasons. Colonized plants had higher nitrogen content than uncolonized plants, although the δ(15N, light environment, total phenolics and leaf mass per area, did not differ between colonized and uncolonized plants. Since colonized and uncolonized plants did not differ in the direct defenses that we evaluated, yet herbivory was lower in colonized plants, we conclude that biotic defenses were the most effective protection against herbivores in our system. This result supports the hypothesis that protection provided by ants is an important factor promoting plant growth. Since C. glaziovii is widely distributed among a variety of forests and ecotones, and since we demonstrated a strong relationship with their ant partners, this system can be useful for comparative studies of ant-plant interactions in different habitats. Also, given this study was carried out near the transition to the subtropics, these results help generalize the geographic distribution of this mutualism and may shed light on the persistence of the interactions in the face of climate change.

  10. The Effect of Symbiotic Ant Colonies on Plant Growth: A Test Using an Azteca-Cecropia System

    Science.gov (United States)

    Oliveira, Karla N.; Coley, Phyllis D.; Kursar, Thomas A.; Kaminski, Lucas A.; Moreira, Marcelo Z.; Campos, Ricardo I.

    2015-01-01

    In studies of ant-plant mutualisms, the role that ants play in increasing the growth rates of their plant partners is potentially a key beneficial service. In the field, we measured the growth of Cecropia glaziovii saplings and compared individuals that were naturally colonized by Azteca muelleri ants with uncolonized plants in different seasons (wet and dry). We also measured light availability as well as attributes that could be influenced by the presence of Azteca colonies, such as herbivory, leaf nutrients (total nitrogen and δ15N), and investments in defense (total phenolics and leaf mass per area). We found that colonized plants grew faster than uncolonized plants and experienced a lower level of herbivory in both the wet and dry seasons. Colonized plants had higher nitrogen content than uncolonized plants, although the δ15N, light environment, total phenolics and leaf mass per area, did not differ between colonized and uncolonized plants. Since colonized and uncolonized plants did not differ in the direct defenses that we evaluated, yet herbivory was lower in colonized plants, we conclude that biotic defenses were the most effective protection against herbivores in our system. This result supports the hypothesis that protection provided by ants is an important factor promoting plant growth. Since C. glaziovii is widely distributed among a variety of forests and ecotones, and since we demonstrated a strong relationship with their ant partners, this system can be useful for comparative studies of ant-plant interactions in different habitats. Also, given this study was carried out near the transition to the subtropics, these results help generalize the geographic distribution of this mutualism and may shed light on the persistence of the interactions in the face of climate change. PMID:25811369

  11. Storage hexamer utilization in two lepidopterans: differences correlated with the timing of egg formation

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    M.L. Pan

    2001-04-01

    Full Text Available Most insects produce two or more storage hexamers whose constituents and developmental profiles are sufficiently different to suggest specialization in the ways that they support metamorphosis and reproduction. Hexamerin specializations are compared here in the Cecropia moth (Hyalophora cecropia, which produces eggs during the pupal-adult molt, and the Monarch butterfly (Danaus plexippus, which produces eggs under long-day conditions after adult eclosion. In both sexes of both species, reserves of arylphorin (ArH were exhausted by the end of metamorphosis. In Cecropia, the same was true for the high-methionine hexamerins, V-MtH and M-MtH. But in short day Monarch females 20-30% of the pupal reserves of V-MtH and M-MtH survived metamorphosis, persisting until long-day conditions were imposed to stimulate egg formation. Differences in storage sites have been documented in other lepidopterans, with MtH reserves being found primarily in fat body protein granules and the ArH reserve being found primarily in the hemolymph. Similar differences could explain how a fraction of the MtH's, but not of ArH, escapes utilization during metamorphosis in a species with post-eclosion egg formation. No differences in utilization schedules were detected between V- and M-MtH, despite divergent compositions and antigenic reactivity.

  12. Evaluation of potentical use of the wood of Schizolobium amazonicum “Paricá” and Cecropia hololeuca “Embaúba” for wood cement board manufacture

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    Vinicius Yurk da Rocha

    2012-06-01

    Full Text Available This research was developed to evaluate the potential use of Schizolobium amazonicum “Paricá” and Cecropia hololeuca “Embaúba” wood for wood cement board manufacture. Panels with the density of 1.200 kg/m³ were made, using cement CP V ARI as mineral bonding and wood particles without treatment and treated with immersion in cold water, hot water and sodium hydroxide. The panels were pressed at the pressure of 40 kgf/cm², room temperature and press / clipping time of 24 hours and maturation time of 28 days. The evaluation of the properties of water absorption, thickness swelling, internal bond, modulus of elasticity and modulus of rupture, showed that Schizolobium amazonicum “Paricá” and Cecropia hololeuca “Embaúba” wood are technically feasible for wood-cement board manufacture. It was also found that the panels of embaúba exhibit some properties superior to those of the paricá, and the particles do not necessarily need treatment.

  13. PHOSPHATE AND INOCULATION WITH ARBUSCULAR MYCORRHIZAL FUNGI ON THE GROWTH OF Cecropia pachystachya (Trec SEEDLINGS FÓSFORO E INOCULAÇÃO COM FUNGOS MICORRÍZICOS ARBUSCULARES NO ESTABELECIMENTO DE MUDAS DE EMBAÚBA (Cecropia pachystachya Trec

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    Marco Aurélio Carbone Carneiro

    2007-09-01

    Full Text Available

    The objective of this study was to evaluate the effect of the inoculation with arbuscular mycorrhizal fungi (FMA in different levels of P2O5 on the growth of Cecropia pachystachya seedlings in the field. The study consisted of a 5x2 factorial with five levels of P2O5 (zero, 85, 170, 255 and 340 mg.kg-1, with and ithout inoculation with a mixture of FMA. It was used four replications, each one with twelve seedlings. The seeds were sowed in plastic tubes with capacity of 50 cm3 of substratum and stored for 120 days. After this period the seedlings were transplanted to the field, where they remained for another 150 days. Seedling diameter and height were measured at 60 and 120 days, aerial part and root dry matter, and arbuscular mycorrhizal colonization. Diameter, height, leaf area, aerial part dry matter and the number of surviving seedlings were determined after 150 days. None of the factors tested had any effect on seedling growth with one exception; inoculated plants with FMA had more root dry matter. Plants inoculated with smaller doses of P2O5 showed a larger percentage of surviving individuals and more vigorous seedlings. Results suggest that in low fertility soils of and subject to the hydric stress the C. pachystachya seedlings should be inoculated with FMA.

    KEY-WORDS: Native vegetation; mycorrhiza fungi; native species; seedling production; inoculation.

    O objetivo deste estudo foi avaliar o efeito da inoculação com fungos micorrízicos arbusculares (FMA em diferentes doses de P2O5 na formação de mudas de embaúba (Cecropia pachystachya e no seu estabelecimento em campo. O estudo constou de um experimento fatorial 5x2, sendo cinco doses de P2O5

  14. Tissue culture of Cecropia glaziovii Sneth (urticaceae: vegetative micropropagation and plant regeneration from callus Cultura de tecidos de Cecropia glaziovii Sneth (Urticaceae: micropropagação vegetativa e regeneração de plantas via calos

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    Marcos Nopper Alves

    2010-10-01

    Full Text Available Cecropia glaziovii is a tree with used in Brazilian popular medicine. Methods allowing the clonal propagation of this species are of great interest for superior genotype multiplication and perpetuation. For this reason, we examined the effect of different culture media and different types of explants on adventitious shoot regeneration from callus and buds of C. glaziovii. Leaves, petioles and stipules obtained from aseptically grown seedlings or from pre-sterilized plants were used to initiate cultures. Adventitious shoot regeneration was achieved when apical and axillary buds were inoculated on gelled Murashige & Skoog (MS medium supplemented with 6-benzylaminopurine alone (BAP (1.0, 5.0 or 10.0 mg L-1 or combined with -naphthalene acetic acid (NAA (1.0 or 2.0 mg L-1, after 40 days of culture. Best callus production was obtained after 30 days of petioles' culture on gelled MS medium with 2,4 dichlorophenoxyacetic acid (2,4-D (5.0 mg L-1 combined with BAP (1.0 mg L-1. Successful shoot regeneration from callus was achieved when MS medium supplemented with zeatin (ZEA (0.1 mg L-1 alone or combined with 2,4-D (1.0 or 5.0 mg L-1 was inoculated with friable callus obtained from petioles. All shoots were rooted by inoculation on MS medium supplemented with indole-3-acetic acid (IAA (1.0 mg L-1. Rooted plants transferred to potting soil were successfully established. All in vitro regenerated plantlets showed to be normal, without morphological variations, being also identical to the source plant. Our study has shown that C. glaziovii can be propagated by tissue culture methods, allowing large scale multiplication of superior plants for pharmacological purposes.Cecropia glaziovii é uma planta lenhosa, popularmente usada no Brasil como medicinal. Métodos que visem a sua propagação clonal podem ser de grande utilidade na preservação de seus genótipos de elite. Foram examinados efeitos de diferentes reguladores de crescimento e explantes na forma

  15. Frugivoria de morcegos (Mammalia, Chiroptera em Cecropia pachystachya (Urticaceae e seus efeitos na germinação das sementes

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    Therys Midori Sato

    2008-01-01

    Full Text Available Os morcegos frugívoros são componentes fundamentais na manutenção e regeneração de florestas tropicais, pois ao se alimentarem, promovem a mobilidade das sementes dos frutos em que se alimentaram. Muito se discute sobre os efeitos da passagem das sementes no trato digestivo dos morcegos sobre a taxa e velocidade de germinação. O objetivo deste trabalho foi examinar a dieta das espécies de morcegos frugívoros na Estação Experimental de Itirapina para descobrir quais utilizam significativamente os frutos de Cecropia pachystachya. Foi testada a importância dos quirópteros na dispersão e germinação desta espécie de planta. Para isso, os morcegos foram capturados no período de agosto de 2005 a julho de 2006, suas fezes foram recolhidas e as sementes de C. pachystachya separadas. Os testes de germinação foram feitos para duas espécies de morcegos, Artibeus liuratus e Platyrrhinus lineatus, e suas taxas de germinação comparadas com amostras de sementes coletadas da planta (controle. Foram feitos cinco repetições com 30 sementes em cada gerbox para cada teste. Os testes foram realizados em câmaras germinadoras " Mangelsdorf" , com temperatura de 25°C, luminosidade e umidade constante por 40 dias. Houve uma alta porcentagem de germinação das sementes encontradas em A. lituratus (79,3% e não diferiu estatisticamente das sementes controle (76%. Esses resultados foram superiores a P. lineatus (52%. Em relação ao Índice de Velocidade de Germinação (IVG, esse resultado foi semelhante, sendo 2,73 para A. lituratus, 2,66 para o controle e 1,80 para P. lineatus. Com esse resultado, tem-se que a passagem das sementes de C. pachystachya pelos morcegos não aumentou a porcentagem, nem a velocidade de germinação delas, quando comparado com o controle, sendo até menor para P. lineatus. Com os resultados obtidos, conclui-se que, o efeito da passagem do trato digestivo dos morcegos na germinação pode sofrer influências que

  16. Avaliação do potencial de utilização da madeira de Schizolobium amazonicum "Paricá" e Cecropia hololeuca "Embaúba" para produção de painéis aglomerados Evaluation of potential use of the wood of Schizolobium amazonicum "Paricá" and Cecropia hololeuca "Embaúba" to particleboard manufacture

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    Setsuo Iwakiri

    2010-01-01

    Full Text Available Esta pesquisa teve por objetivo avaliar o potencial de utilização de madeira de Schizolobium amazonicum (Paricá e Cecropia hololeuca (Embaúba para produção de painéis aglomerados. Foram produzidos painéis experimentais com densidade nominal de 0,70 g/cm³, utilizando a resina uréia-formaldeído e partículas de madeira de Paricá e Embaúba, e mistura destas, em proporções de 75, 50 e 25%. A madeira de Pinus taeda foi utilizada como testemunha. Os painéis foram prensados com pressão específica de 40 kgf/cm², temperatura de 160ºC e tempo de prensagem de 8 minutos. Os resultados das avaliações de propriedades de absorção de água, inchamento em espessura, ligação interna, módulo de elasticidade e módulo de ruptura, indicaram que as madeiras de Schizolobium amazonicum (Paricá e Cecropia hololeuca (Embaúba são tecnicamente viáveis para produção de painéis aglomerados.This research was developed to evaluate the potential use of the woods Schizolobium amazonicum (Paricá and Cecropia hololeuca (Embaúba for manufacturing particleboard. Were made panels with the densities of 0.70 g/cm³, using mixtures of urea-formaldehyde resin and wood particles of Paricá and Embaúba, in proportions of 75, 50 and 25%. The Pinus taeda wood was used as the reference. The panels were pressed at the temperature of 160ºC, pressure of 40 kgf/cm², for 8 minutes. The evaluations of the properties of water absorption, thickness swelling, internal bond, modulus of elasticity and modulus of ruptures, showed that the woods of Schizolobium amazonicum (Paricá e Cecropia hololeuca (Embaúba are technically feasible for particleboard manufacture.

  17. Nest structure and occurrence of three species of Azteca (Hymenoptera, Formicidae in Cecropia pachystachya (Urticaceae in non-floodable and floodable pantanal areas Arquitetura de ninho e ocorrência de três espécies de Azteca (Hymenoptera, Formicidae em Cecropia pachystachya (Urticaceae em ambiente alagável e não alagável no Pantanal

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    Alexsandro S. Vieira

    2010-01-01

    Full Text Available Thirty Cecropia pachystachya trees were examined in non-floodable and floodable areas to investigate the association between C. pachystachya and Azteca ants in the Pantanal of Mato Grosso do Sul, Brazil. The species Azteca ovaticeps, Azteca isthmica, and Azteca alfari were found nesting inside domatia of C. pachystachya. A. ovaticeps was the most frequent species in the trees in the floodable area, while A. isthmica and A. alfari, in the non-floodable area. A. ovaticeps and A. isthmica maintained more entrance/exit holes in comparison to A. alfari. All Azteca species maintained entrance/exit holes in the closest domatia to the apical area of the branch, due to proximity to Müllerian and pearl bodies, suggesting that these species of Azteca were influenced by their environment during evolution and became specialized. All internodal septa of each examined branch were perforated by ants, indicating the branches were inhabited by a single colony.Foram analisadas 30 plantas de Cecropia pachystachya em cada ambiente alagável e não alagável no Pantanal sul-mato-grossense, Brasil, com o objetivo de investigar a associação entre formigas Azteca e C. pachystachya. Foram encontradas as espécies Azteca ovaticeps, Azteca isthmica e Azteca alfari nidificando nas domáceas da planta. A. ovaticeps foi mais frequente em plantas de área alagável, enquanto A. isthmica e A. alfari em plantas em área não alagável. A. ovaticeps e A. isthmica apresentaram maior quantidade de orifícios de entrada/saída em relação à A. alfari e todas as espécies mantêm próximo da região apical do ramo, orifícios de entrada/saída nas domáceas, devido à proximidade com os corpúsculos müellerianos e pérola. Isto é, essas espécies de Azteca especializaram-se ao longo da evolução influenciadas pelo ambientes. Todos os septos internodais de cada ramo analisados apresentaram-se perfurados pelas formigas, sugerindo que os mesmos são habitados por uma única colônia.

  18. Taxa e velocidade de germinação de sementes de Cecropia pachystachya Trécul (Cecropiaceae ingeridas por Artibeus lituratus (Olfers, 1818 (Chiroptera: Phyllostomidae = Germination rate and velocity of seeds of Cecropia pachystachya Trécul (Cecropiaceae eaten by Artibeus lituratus (Olfers, 1818 (Chiroptera: Phyllostomidae

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    Ricardo Anghinoni Bocchese

    2007-10-01

    Full Text Available O objetivo deste trabalho foi verificar se o morcego frugívoro Artibeus lituratus pode ser considerado indutor na germinação de sementes de Cecropia pachystachya, sendo avaliadas a taxa e a velocidade de germinação das sementes em diferentes condições. Osmorcegos e os frutos foram coletados na região central de Campo Grande, Estado do Mato Grosso do Sul; o experimento foi dividido em cinco tratamentos. O primeiro contou com sementes retiradas dos frutos; o segundo, com sementes retiradas das fezes, e o terceirodividido em três tratamentos ácidos, com concentrações de pH 1, 2 e 3. As sementes que passaram pelo sistema digestório dos animais germinaram com maior velocidade (p 0,05 quandocomparada às sementes sem tratamento. O tratamento com pH igual a 3 foi estatisticamente igual ao grupo sem tratamento e ao grupo experimental, com sementes retiradas das fezes, indicando o valor aproximado da concentração dos ácidos estomacais desta espéciefrugívora. Conclui-se que Artibeus lituratus pode ser considerado indutor do aumento da velocidade de germinação nas sementes desta espécie vegetal, refletindo na importância desta espécie frugívora na manutenção ecológica dos ecossistemas tropicais, principalmenteem áreas de Cerrado.The objective with this study was to verify whether frugivorous bat Artibeus lituratus can be considered an efficient germination inducer for Cecropia pachystachya seeds. Bats and fruits were collected in Campo Grande (Mato Grosso do Sul State, Brazil, with the experimentbeing divided in five treatments: one composed by seeds taken from natural fresh fruits, another with seeds taken from the bats’ excrements, and the last one sub-divided in three sub-groups with different acid treatments that corresponded to pH 1, 2 and 3. The seeds that passed through the digestive tract of the animals presented a higher germination velocity index (p 0.05 when compared with the seeds without any treatment. The

  19. Chlorinated tyrosine derivatives in insect cuticle

    DEFF Research Database (Denmark)

    Andersen, Svend Olav

    2004-01-01

    during sample hydrolysis. Mono- and dichlorotyrosine are also present in cuticular samples from other insect species, such as the beetle, Tenebrio molitor, the moth Hyalophora cecropia, the cockroach Blaberus craniifer, and the bug Rhodnius prolixus, but not in the sclerotized puparial cuticle...... of the blowfly, Calliphora vicina, or in sclerotized ootheca from the cockroach, Periplaneta americana. Cuticular sclerotization and formation of chlorotyrosines occur simultaneously in locust legs; sclerotized cuticles tend to have a higher content of chlorotyrosines than unsclerotized cuticles...

  20. Taxa e velocidade de germinação de sementes de Cecropia pachystachya Trécul (Cecropiaceae ingeridas por Artibeus lituratus (Olfers, 1818 (Chiroptera: Phyllostomidae - DOI: 10.4025/actascibiolsci.v29i4.879 Germination rate and velocity of seeds of Cecropia pachystachya Trécul (Cecropiaceae eaten by Artibeus lituratus (Olfers, 1818 (Chiroptera: Phyllostomidae - DOI: 10.4025/actascibiolsci.v29i4.879

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    Eliane Cristine Vicente

    2008-02-01

    Full Text Available O objetivo deste trabalho foi verificar se o morcego frugívoro Artibeus lituratus pode ser considerado indutor na germinação de sementes de Cecropia pachystachya, sendo avaliadas a taxa e a velocidade de germinação das sementes em diferentes condições. Os morcegos e os frutos foram coletados na região central de Campo Grande, Estado do Mato Grosso do Sul; o experimento foi dividido em cinco tratamentos. O primeiro contou com sementes retiradas dos frutos; o segundo, com sementes retiradas das fezes, e o terceiro dividido em três tratamentos ácidos, com concentrações de pH 1, 2 e 3. As sementes que passaram pelo sistema digestório dos animais germinaram com maior velocidade (p 0,05 quando comparada às sementes sem tratamento. O tratamento com pH igual a 3 foi estatisticamente igual ao grupo sem tratamento e ao grupo experimental, com sementes retiradas das fezes, indicando o valor aproximado da concentração dos ácidos estomacais desta espécie frugívora. Conclui-se que Artibeus lituratus pode ser considerado indutor do aumento da velocidade de germinação nas sementes desta espécie vegetal, refletindo na importância desta espécie frugívora na manutenção ecológica dos ecossistemas tropicais, principalmente em áreas de Cerrado.The objective with this study was to verify whether frugivorous bat Artibeus lituratus can be considered an efficient germination inducer for Cecropia pachystachya seeds. Bats and fruits were collected in Campo Grande (Mato Grosso do Sul State, Brazil, with the experiment being divided in five treatments: one composed by seeds taken from natural fresh fruits, another with seeds taken from the bats’ excrements, and the last one sub-divided in three sub-groups with different acid treatments that corresponded to pH 1, 2 and 3. The seeds that passed through the digestive tract of the animals presented a higher germination velocity index (p 0.05 when compared with the seeds without any treatment. The

  1. Avaliação do efeito mutagênico do extrato hidroalcoólico bruto, por meio de bioensaios in vivo e prospecção fitoquímica de Cecropia glaziovii Sneth (embaúba, Cecropiaceae Evaluation of mutagenic effect of crude hydroalchoolic extract, using in vivo alive bioassays and phytochemical screening of Cecropia glaziovii Sneth (embaúba, Cecropiaceae

    Directory of Open Access Journals (Sweden)

    Victor S. Stange

    2009-06-01

    Full Text Available O gênero Cecropia é conhecido popularmente por "embaúba" e apresenta várias espécies medicinais, sendo que estudos com a espécie C. glaziovii Sneth indicam que o extrato aquoso apresenta efeitos broncodilatador, anti-hipertensivo e antidepressivo, provavelmente, atribuídos às catequinas, procianidinas e flavonóides. O presente estudo objetivou avaliar os potenciais efeitos tóxico, citotóxicos, clastogênicos e aneugênicos do extrato bruto hidroalcoólico de folhas de C. glaziovii, por meio da dose letal média (DL50, da análise de micronúcleo em células de medula óssea de roedores e do teste com Allium cepa e realizar a prospecção fitoquímica. Os resultados demonstraram que as concentrações testadas não causaram toxicidade aguda, nem apresentaram atividade clastogênica e aneugênica, sugerindo que o extrato de C. glaziovii não interferem na divisão celular. A prospecção fitoquímica indicou a presença de taninos, flavonóides, fenóis, antraquinonas, cumarinas, catequinas, proteínas, açúcares redutores, depsídeos/depsidonas e triterpenos. Mesmo assim, esses resultados não prescrevem o consumo terapêutico da espécie, sem continuidade da sua avaliação e do cumprimento de todas as etapas pré-clínicas e clínicas.The genus Cecropia is as known popularly "embaúba" and presents several medical species. Studies with the species C. glaziovii Sneth indicates that the hydroalchoolic extracts presents bronchodilator, anti-hypertensive and antidepressive effects, probably due its contests catechins, procyanidins and flavonoids. The aim of this study was to assess the potential toxic, cytotoxic, clastogenic and aneugenic effects of the crude hydroalchoolic extract of leaves of C. glaziovii, by means of the determination of the median lethal dose (LD50, the analysis of micronucleus in cells from bone marrow of rodents and through the Allium cepa assay, and also to performe the phytochemical screening. The results showed

  2. Growth Stimulants

    OpenAIRE

    Matthews, Nyle J.

    1989-01-01

    A tiny pellet inserted under the skin of a calf's ear may increase weight gains as much as 15 to 20 percent. This same result would take years to accomplish through breeding and selection. These tiny pellets are growth stimulants. They are made of hormones that are constructed to slowly release minute amounts into the blood stream that stimulate the animal to produce natural body hormones. One of these hormones is a growth hormone. It regulates the rate of growth of the animal. Increasing the...

  3. Vagus Nerve Stimulation

    Science.gov (United States)

    Vagus nerve stimulation Overview By Mayo Clinic Staff Vagus nerve stimulation is a procedure that involves implantation of a device that stimulates the vagus nerve with electrical impulses. There's one vagus nerve on ...

  4. Brain Stimulation Therapies

    Science.gov (United States)

    ... is preferred by many doctors, patients and families. Vagus Nerve Stimulation Vagus nerve stimulation (VNS) works through a device implanted under ... skin that sends electrical pulses through the left vagus nerve, half of a prominent pair of nerves that ...

  5. Feldspar, Infrared Stimulated Luminescence

    DEFF Research Database (Denmark)

    Jain, Mayank

    2014-01-01

    This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars.......This entry primarily concerns the characteristics and the origins of infrared-stimulated luminescence in feldspars....

  6. An Overview of Stimulators

    OpenAIRE

    Mohd. Suhaib Kidwai; Mohd Maroof Siddiqui; Ahmad Nafees; Qazi saeed Ahmad

    2012-01-01

    This paper aims to bring forth the significance of stimulators , recent advancements in the field of stimulators and how electrical signals can be utilized for pain relief and to cure other diseases of human body ,by using stimulators. This paper aims to create awareness about stimulators and also focuses on their advantages as compared to theconventional medicine .Moreover,it also bring forth that how an electrical signal can be utilized for treating various human disorders and diseases.

  7. Triagem fitoquímica e avaliação das atividades trombolítica e citotóxica de Cecropia hololeuca Miq. (Urticaceae, Lippia alba (Mill. N.E.Br. ex P. Wilson (Verbenaceae e Zanthoxylum rhoifolium Lam (Rutaceae

    Directory of Open Access Journals (Sweden)

    João Victor Dutra GOMES1 ; Rafael Destefani FAITANIN

    2016-03-01

    Full Text Available Cecropia hololeuca, Lippia alba, e Zanthoxylum rhoifolium são espécies vegetais de ocorrência natural no Brasil, características de regiões de Mata Atlântica e, dentro de suas finalidades medicinais, estão incluídas ação anti-hipertensiva, digestiva e no tratamento de malária. Neste estudo, foram avaliados o perfil fitoquímico e as atividades citotóxica e trombolítica do extrato etanólico das folhas destas espécies vegetais. O perfil químico dos extratos foi obtido por meio de ensaios fitoquímicos clássicos, a fim de identificar as classes químicas presentes. A toxicidade preliminar foi avaliada frente Artemia salina e a atividade trombolítica foi determinada in vitro a partir da lise de coágulo de sangue humano. Os testes fitoquímicos indicaram a presença de alcaloides e flavonoides nos três extratos investigados. Saponinas, triterpenos e naftoquinonas foram detectados apenas em C. hololeuca. Essa não demonstrou toxicidade frente Artemia salina (DL50 >1000 ppm, enquanto Z. rhoifolium apresentou DL50 igual a 719,44 ppm e L. alba <250 ppm, o que indica atenção quanto à segurança no uso desta planta medicinal. A atividade trombolítica de L. alba e C. hololeuca foi de 6,43 ±2,08 e 9,64 ±1,83 %, respectivamente, mostrando baixa atividade. Por sua vez, Z. rhoifolium alcançou lise de 24,71 ±10,52 %, indicando promissora atividade (p <0,001. A atividade trombolítica de Z. rhoifolium justifica novos estudos, a fim de investigar os componentes responsáveis pela atividade. Perante a literatura, este é o primeiro relato da avaliação da atividade trombolítica destas espécies vegetais. Os resultados encontrados neste trabalho contribuem para o conhecimento químico-biológico das respectivas espécies.

  8. Stimulate your creativity

    Energy Technology Data Exchange (ETDEWEB)

    Raudsepp, E.

    1983-02-01

    Aids in idea stimulation and problem solving are presented. The forced relation technique forces random words together to stimulate thought. This can be done by the catalog method or by listing characteristics and alternatives until a novel idea occurs. A checklist designed for mathematical problem solving is given. The forms of questioning it provides include understanding the unknown and finding a connection between the data and the unknown. A vice-versa checklist, where consideration of the opposite encourages new ideas, is suggested. A self-questioning attitude is necessary for problem-solving. A word stimulation by checklist is also suggested.

  9. Deep brain stimulation

    Science.gov (United States)

    ... a device called a neurostimulator to deliver electrical signals to the areas of the brain that control ... neurostimulator, which puts out the electric current. The stimulator is similar to a heart ...

  10. Geothermal Well Stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, D. A.; Morris, C. W.; Sinclair, A. R.; Hanold, R. J.; Vetter, O. J.

    1981-03-01

    The stimulation of geothermal wells presents some new and challenging problems. Formation temperatures in the 300-600 F range can be expected. The behavior of stimulation fluids, frac proppants, and equipment at these temperatures in a hostile brine environment must be carefully evaluated before performance expectations can be determined. In order to avoid possible damage to the producing horizon of the formation, high temperature chemical compatibility between the in situ materials and the stimulation materials must be verified. Perhaps most significant of all, in geothermal wells the required techniques must be capable of bringing about the production of very large amounts of fluid. This necessity for high flow rates represents a significant departure from conventional petroleum well stimulation and demands the creation of very high near-wellbore permeability and/or fractures with very high flow conductivity.

  11. New York Canyon Stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Raemy, Bernard

    2012-06-21

    The New York Canyon Stimulation Project was to demonstrate the commercial application of Enhanced Geothermal System techniques in Buena Vista Valley area of Pershing County, Nevada. From October 2009 to early 2012, TGP Development Company aggressively implemented Phase I of Pre-Stimulation and Site/Wellbore readiness. This included: geological studies; water studies and analyses and procurement of initial permits for drilling. Oversubscription of water rights and lack of water needed for implementation of EGS were identified and remained primary obstacles. Despite extended efforts to find alternative solutions, the water supply circumstances could not be overcome and led TGP to determine a "No Go" decision and initiate project termination in April 2012.

  12. Magnetic Stimulation and Epilepsy

    Science.gov (United States)

    2013-10-14

    investigated using behavioral recording and electroencephalographic (EEG) recording. The results (Figures 1~7) obtained have been submitted to Epilepsia ...Magnetic Stimulation on Penicillin-Induced Seizures in Rats. Epilepsia (submitted). * corresponding author. IV. OTHER CHANGES N/A V. FUTURE PLANS

  13. Cognitive stimulation in brainstorming.

    Science.gov (United States)

    Dugosh, K L; Paulus, P B; Roland, E J; Yang, H C

    2000-11-01

    Research on group brainstorming has demonstrated that it is less effective for generating large numbers of ideas than individual brainstorming, yet various scholars have presumed that group idea sharing should enhance cognitive stimulation and idea production. Three experiments examined the potential of cognitive stimulation in brainstorming. Experiments 1 and 2 used a paradigm in which individuals were exposed to ideas on audiotape as they were brainstorming, and Experiment 3 used the electronic brainstorming paradigm. Evidence was obtained for enhanced idea generation both during and after idea exposure. The attentional set of the participant and the content of the exposure manipulation (number of ideas, presence of irrelevant information) influenced this effect. These results are consistent with a cognitive perspective on group brainstorming.

  14. Sacral nerve stimulation.

    Science.gov (United States)

    Matzel, K E; Stadelmaier, U; Besendörfer, M

    2004-01-01

    The current concept of recruiting residual function of an inadequate pelvic organ by electrostimulation involves stimulation of the sacral spinal nerves at the level of the sacral canal. The rationale for applying SNS to fecal incontinence was based on clinical observations of its effect on bowel habits and anorectal continence function in urologic patients (increased anorectal angulation and anal canal closure pressure) and on anatomic considerations: dissection demonstrated a dual peripheral nerve supply of the striated pelvic floor muscles that govern these functions. Because the sacral spinal nerve site is the most distal common location of this dual nerve supply, stimulating here can elicit both functions. Since the first application of SNS in fecal incontinence in 1994, this technique has been improved, the patient selection process modified, and the spectrum of indications expanded. At present SNS has been applied in more than 1300 patients with fecal incontinence limited.

  15. Raft River well stimulation experiments: geothermal reservoir well stimulation program

    Energy Technology Data Exchange (ETDEWEB)

    1980-08-01

    The Geothermal Reservoir Well Stimulation Program (GRWSP) performed two field experiments at the Raft River KGRA in 1979. Wells RRGP-4 and RRGP-5 were selected for the hydraulic fracture stimulation treatments. The well selection process, fracture treatment design, field execution, stimulation results, and pre- and post-job evaluations are presented.

  16. Human Tissue Stimulator

    Science.gov (United States)

    1982-01-01

    Neurodyne Corporation Human Tissue Stimulator (HTS) is a totally implantable system used for treatment of chronic pain and involuntary motion disorders by electrical stimulation. It was developed by Pacesetter Systems, Inc. in cooperation with the Applied Physics Laboratory. HTS incorporates a nickel cadmium battery, telemetry and command systems technologies of the same type as those used in NASA's Small Astronomy Satellite-3 in microminiature proportions so that the implantable element is the size of a deck of cards. The stimulator includes a rechargeable battery, an antenna and electronics to receive and process commands and to report on its own condition via telemetry, a wireless process wherein instrument data is converted to electrical signals and sent to a receiver where signals are presented as usable information. The HTS is targeted to nerve centers or to particular areas of the brain to provide relief from intractable pain or arrest involuntary motion. The nickel cadmium battery can be recharged through the skin. The first two HTS units were implanted last year and have been successful. Extensive testing is required before HTS can be made available for general use.

  17. Self-Stimulated Undulator Klystron

    OpenAIRE

    Bessonov, E. G.; Osipov, A. L.; Mikhailichenko, A. A.

    2011-01-01

    The Self Stimulated Undulator Klystron (SSUK) and its possible applications in the Particle Accelerator Physics, incoherent Self-Stimulated Undulator Radiation Sources (SSUR) and Free-Electron Lasers (FEL) are discussed.

  18. Spinal Cord Stimulation

    DEFF Research Database (Denmark)

    Meier, Kaare

    2014-01-01

    pain after failed back surgery syndrome (FBSS)(4), pain due to peripheral nerve injury, stump pain(5), peripheral vascular disease(6) and diabetic neuropathy(7,8); whereas phantom pain(9), postherpetic neuralgia(10), chronic visceral pain(11), and pain after partial spinal cord injury(12) remain more......Spinal cord stimulation (SCS) is a surgical treatment for chronic neuropathic pain that is refractory to other treatment. Originally described by Shealy et al. in 1967(1), it is used to treat a range of conditions such as complex regional pain syndrome (CRPS I)(2), angina pectoris(3), radicular...

  19. Central nervous system stimulants.

    Science.gov (United States)

    George, A J

    2000-03-01

    Three major types of CNS stimulant are currently abused in sport: amphetamine, cocaine and caffeine. Each drug type has its own characteristic mechanism of action on CNS neurones and their associated receptors and nerve terminals. Amphetamine is widely abused in sports requiring intense anaerobic exercise where it prolongs the tolerance to anaerobic metabolism. It is addictive, and chronic abuse causes marked behavioural change and sometimes psychosis. Major sports abusing amphetamine are cycling, American football, ice-hockey and baseball. Cocaine increases tolerance to intense exercise, yet most of its chronic effects on energy metabolism are negative. Its greatest effects seem to be as a central stimulant and the enhancement of short-term anaerobic exercise. It is highly addictive and can cause cerebral and cardiovascular fatalities. Caffeine enhances fatty acid metabolism leading to glucose conservation, which appears to benefit long-distance endurance events such as skiing. Caffeine is also addictive, and chronic abuse can lead to cardiac damage. Social abuse of each of the three drugs is often difficult to distinguish from their abuse in sport.

  20. Transcranial brain stimulation: closing the loop between brain and stimulation

    DEFF Research Database (Denmark)

    Karabanov, Anke; Thielscher, Axel; Siebner, Hartwig Roman

    2016-01-01

    PURPOSE OF REVIEW: To discuss recent strategies for boosting the efficacy of noninvasive transcranial brain stimulation to improve human brain function. RECENT FINDINGS: Recent research exposed substantial intra- and inter-individual variability in response to plasticity-inducing transcranial brain...... transcranial brain stimulation. Priming interventions or paired associative stimulation can be used to ‘standardize’ the brain-state and hereby, homogenize the group response to stimulation. Neuroanatomical and neurochemical profiling based on magnetic resonance imaging and spectroscopy can capture trait......-related and state-related variability. Fluctuations in brain-states can be traced online with functional brain imaging and inform the timing or other settings of transcranial brain stimulation. State-informed open-loop stimulation is aligned to the expression of a predefined brain state, according to prespecified...

  1. Brain stimulation for intractable epilepsy: Anterior thalamus and responsive stimulation

    Directory of Open Access Journals (Sweden)

    Vibhor Krishna

    2014-01-01

    Full Text Available Despite medications, resective surgery, and vagal nerve stimulation, some patients with epilepsy continue to have seizures. In these patients, other approaches are urgently needed. The biological basis of stimulation of anterior thalamic nucleus and epileptogenic focus is presented. Results from two large randomized controlled trials Stimulation of Anterior Nucleus of Thalamus for Epilepsy (SANTE and Neuropace pivotal trial are discussed. Neuromodulation provides effective treatment for a select group of refractory epilepsy patients. Future investigations into the mechanism underlying ′response′ to brain stimulation are desired.

  2. Collective stimulated Brillouin scatter

    CERN Document Server

    Korotkevich, Alexander O; Rose, Harvey A

    2011-01-01

    We develop a statistical theory of stimulated Brillouin backscatter (BSBS) of a spatially and temporally partially incoherent laser beam for laser fusion relevant plasma. We find a new collective regime of BSBS which has a much larger threshold than the classical threshold of a coherent beam in long-scale-length laser fusion plasma. We identify two contributions to BSBS convective instability increment. The first is collective with intensity threshold independent of the laser correlation time and controlled by diffraction. The second is independent of diffraction, it grows with increase of the correlation time and does not have an intensity threshold. The instability threshold is inside the typical parameter region of National Ignition Facility (NIF). We also find that the bandwidth of KrF-laser-based fusion systems would be large enough to allow additional suppression of BSBS.

  3. Collective stimulated Brillouin backscatter

    CERN Document Server

    Lushnikov, Pavel M

    2007-01-01

    We develop the statistical theory of the stimulated Brillouin backscatter (BSBS) instability of a spatially and temporally partially incoherent laser beam for laser fusion relevant plasma. We find a new regime of BSBS which has a much larger threshold than the classical threshold of a coherent beam in long-scale-length laser fusion plasma. Instability is collective because it does not depend on the dynamics of isolated speckles of laser intensity, but rather depends on averaged beam intensity. We identify convective and absolute instability regimes. Well above the incoherent threshold the coherent instability growth rate is recovered. The threshold of convective instability is inside the typical parameter region of National Ignition Facility (NIF) designs although current NIF bandwidth is not large enough to insure dominance of collective instability and suggests lower instability threshold due to speckle contribution. In contrast, we estimate that the bandwidth of KrF-laser-based fusion systems would be larg...

  4. Myeloperoxidase Stimulates Neutrophil Degranulation.

    Science.gov (United States)

    Grigorieva, D V; Gorudko, I V; Sokolov, A V; Kostevich, V A; Vasilyev, V B; Cherenkevich, S N; Panasenko, O M

    2016-08-01

    Myeloperoxidase, heme enzyme of azurophilic granules in neutrophils, is released into the extracellular space in the inflammation foci. In neutrophils, it stimulates a dose-dependent release of lactoferrin (a protein of specific granules), lysozyme (a protein of specific and azurophilic granules), and elastase (a protein of azurophilic granules). 4-Aminobenzoic acid hydrazide, a potent inhibitor of peroxidase activity of myeloperoxidase, produced no effect on neutrophil degranulation. Using signal transduction inhibitors (genistein, methoxyverapamil, wortmannin, and NiCl2), we demonstrated that myeloperoxidase-induced degranulation of neutrophils resulted from enzyme interaction with the plasma membrane and depends on activation of tyrosine kinases, phosphatidylinositol 3-kinases (PI3K), and calcium signaling. Myeloperoxidase modified by oxidative/halogenation stress (chlorinated and monomeric forms of the enzyme) lost the potency to activate neutrophil degranulation.

  5. Stimulated Cavity-Optomechanics

    CERN Document Server

    Bahl, Gaurav; Tomes, Matthew; Carmon, Tal

    2011-01-01

    Stimulated Brillouin interaction between sound and light, known to be the strongest optical nonlinearity common to all amorphous and crystalline dielectrics, has been widely studied in fibers and bulk materials but rarely in optical microresonators. The possibility of experimentally extending this principle to excite mechanical resonances in photonic microsystems, for sensing and frequency reference applications, has remained largely unexplored. The challenge lies in the fact that microresonators inherently have large free spectral range, while the phase matching considerations for the Brillouin process require optical modes of nearby frequencies but with different wavevectors. We rely on high-order transverse optical modes to relax this limitation. Here we report on the experimental excitation of mechanical resonances ranging from 49 to 1400 MHz by using forward Brillouin scattering. These natural mechanical resonances are excited in ~100 um silica microspheres, and are of a surface-acoustic whispering-galle...

  6. Stimulated coherent transition radiation

    Energy Technology Data Exchange (ETDEWEB)

    Hung-chi Lihn

    1996-03-01

    Coherent radiation emitted from a relativistic electron bunch consists of wavelengths longer than or comparable to the bunch length. The intensity of this radiation out-numbers that of its incoherent counterpart, which extends to wavelengths shorter than the bunch length, by a factor equal to the number of electrons in the bunch. In typical accelerators, this factor is about 8 to 11 orders of magnitude. The spectrum of the coherent radiation is determined by the Fourier transform of the electron bunch distribution and, therefore, contains information of the bunch distribution. Coherent transition radiation emitted from subpicosecond electron bunches at the Stanford SUNSHINE facility is observed in the far-infrared regime through a room-temperature pyroelectric bolometer and characterized through the electron bunch-length study. To measure the bunch length, a new frequency-resolved subpicosecond bunch-length measuring system is developed. This system uses a far-infrared Michelson interferometer to measure the spectrum of coherent transition radiation through optical autocorrelation with resolution far better than existing time-resolved methods. Hence, the radiation spectrum and the bunch length are deduced from the autocorrelation measurement. To study the stimulation of coherent transition radiation, a special cavity named BRAICER is invented. Far-infrared light pulses of coherent transition radiation emitted from electron bunches are delayed and circulated in the cavity to coincide with subsequent incoming electron bunches. This coincidence of light pulses with electron bunches enables the light to do work on electrons, and thus stimulates more radiated energy. The possibilities of extending the bunch-length measuring system to measure the three-dimensional bunch distribution and making the BRAICER cavity a broadband, high-intensity, coherent, far-infrared light source are also discussed.

  7. Optically stimulated differential impedance spectroscopy

    Science.gov (United States)

    Maxey, Lonnie C; Parks, II, James E; Lewis, Sr., Samuel A; Partridge, Jr., William P

    2014-02-18

    Methods and apparatuses for evaluating a material are described. Embodiments typically involve use of an impedance measurement sensor to measure the impedance of a sample of the material under at least two different states of illumination. The states of illumination may include (a) substantially no optical stimulation, (b) substantial optical stimulation, (c) optical stimulation at a first wavelength of light, (d) optical stimulation at a second wavelength of light, (e) a first level of light intensity, and (f) a second level of light intensity. Typically a difference in impedance between the impedance of the sample at the two states of illumination is measured to determine a characteristic of the material.

  8. Electrical stimulation and muscle strengthening

    National Research Council Canada - National Science Library

    Dehail, P; Duclos, C; Barat, M

    2008-01-01

    ...: muscular or neuromuscular, electromyostimulation, electrical stimulation, strengthening, strength training, immobilization, muscle dystrophy, bed-rest, bed-bound, knee or hip surgery, postoperative...

  9. EOR by stimulated microflora

    Energy Technology Data Exchange (ETDEWEB)

    Svarovskaya, L.I.; Altunina, L.K.; Rozhenkova, Z.A.; Bulavin, V.D. [Institute of Petroleum Chemistry, Tomsk (Russian Federation)

    1995-12-31

    A combined microbiological and physico-chemical method for EOR has been developed for flooded West Siberia oil fields with formation temperature of 45{degrees}-95{degrees}C (318-365K). Formation water includes rich and various biocenoses numbering up to 2 x 10{sup 7} cells per ml. Representatives of genera, i.e, Pseudomonas, Bacillus, Actinomyces, Micrococcus, Mycobacterium, Sarcina, etc. were found to be the most widely distributed microorganisms. The method is based on injection of systems exhibiting high oil displacing capacity and at the same time being an additional nitrous nutrient for endemic populations of microorganisms. Their injection into formation water favors biomass growth by 4-6 orders and promotes syntheses of biosurfactants, biopolymers, acids, etc., and gaseous products. The features of residual oil displacement have been studied on laboratory models using a combined microbiological and physico-chemical method. A curve for the yield of residual oil is presented by two peaks. The first peak is stipulated by the washing action of oil displacement system, and the second one by the effect of metabolites produced at stimulation of biogenic processes. Oil displacement index increases by 15%-30%.

  10. Stimulating Language: Insights from TMS

    Science.gov (United States)

    Devlin, Joseph T.; Watkins, Kate E.

    2007-01-01

    Fifteen years ago, Pascual-Leone and colleagues used transcranial magnetic stimulation (TMS) to investigate speech production in pre-surgical epilepsy patients and in doing so, introduced a novel tool into language research. TMS can be used to non-invasively stimulate a specific cortical region and transiently disrupt information processing. These…

  11. Low intensity transcranial electric stimulation

    DEFF Research Database (Denmark)

    Antal, Andrea; Alekseichuk, I; Bikson, M

    2017-01-01

    Low intensity transcranial electrical stimulation (TES) in humans, encompassing transcranial direct current (tDCS), transcutaneous spinal Direct Current Stimulation (tsDCS), transcranial alternating current (tACS), and transcranial random noise (tRNS) stimulation or their combinations, appears...... following stimulation as well as prickling and burning sensations occurring during tDCS at peak-to-baseline intensities of 1-2mA and during tACS at higher peak-to-peak intensities above 2mA. The prevalence of published AEs is different in studies specifically assessing AEs vs. those not assessing them......, being higher in the former. AEs are frequently reported by individuals receiving placebo stimulation. The profile of AEs in terms of frequency, magnitude and type is comparable in healthy and clinical populations, and this is also the case for more vulnerable populations, such as children, elderly...

  12. Nanomaterial-enabled neural stimulation

    Directory of Open Access Journals (Sweden)

    Yongchen eWang

    2016-03-01

    Full Text Available Neural stimulation is a critical technique in treating neurological diseases and investigating brain functions. Traditional electrical stimulation uses electrodes to directly create intervening electric fields in the immediate vicinity of neural tissues. Second-generation stimulation techniques directly use light, magnetic fields or ultrasound in a non-contact manner. An emerging generation of non- or minimally invasive neural stimulation techniques is enabled by nanotechnology to achieve a high spatial resolution and cell-type specificity. In these techniques, a nanomaterial converts a remotely transmitted primary stimulus such as a light, magnetic or ultrasonic signal to a localized secondary stimulus such as an electric field or heat to stimulate neurons. The ease of surface modification and bio-conjugation of nanomaterials facilitates cell-type-specific targeting, designated placement and highly localized membrane activation. This review focuses on nanomaterial-enabled neural stimulation techniques primarily involving opto-electric, opto-thermal, magneto-electric, magneto-thermal and acousto-electric transduction mechanisms. Stimulation techniques based on other possible transduction schemes and general consideration for these emerging neurotechnologies are also discussed.

  13. Nanomaterial-Enabled Neural Stimulation.

    Science.gov (United States)

    Wang, Yongchen; Guo, Liang

    2016-01-01

    Neural stimulation is a critical technique in treating neurological diseases and investigating brain functions. Traditional electrical stimulation uses electrodes to directly create intervening electric fields in the immediate vicinity of neural tissues. Second-generation stimulation techniques directly use light, magnetic fields or ultrasound in a non-contact manner. An emerging generation of non- or minimally invasive neural stimulation techniques is enabled by nanotechnology to achieve a high spatial resolution and cell-type specificity. In these techniques, a nanomaterial converts a remotely transmitted primary stimulus such as a light, magnetic or ultrasonic signal to a localized secondary stimulus such as an electric field or heat to stimulate neurons. The ease of surface modification and bio-conjugation of nanomaterials facilitates cell-type-specific targeting, designated placement and highly localized membrane activation. This review focuses on nanomaterial-enabled neural stimulation techniques primarily involving opto-electric, opto-thermal, magneto-electric, magneto-thermal and acousto-electric transduction mechanisms. Stimulation techniques based on other possible transduction schemes and general consideration for these emerging neurotechnologies are also discussed.

  14. Vagal nerve stimulation therapy: what is being stimulated?

    Directory of Open Access Journals (Sweden)

    Guy Kember

    Full Text Available Vagal nerve stimulation in cardiac therapy involves delivering electrical current to the vagal sympathetic complex in patients experiencing heart failure. The therapy has shown promise but the mechanisms by which any benefit accrues is not understood. In this paper we model the response to increased levels of stimulation of individual components of the vagal sympathetic complex as a differential activation of each component in the control of heart rate. The model provides insight beyond what is available in the animal experiment in as much as allowing the simultaneous assessment of neuronal activity throughout the cardiac neural axis. The results indicate that there is sensitivity of the neural network to low level subthreshold stimulation. This leads us to propose that the chronic effects of vagal nerve stimulation therapy lie within the indirect pathways that target intrinsic cardiac local circuit neurons because they have the capacity for plasticity.

  15. Digital electronic bone growth stimulator

    Energy Technology Data Exchange (ETDEWEB)

    Kronberg, James W. (Aiken, SC)

    1995-01-01

    A device for stimulating bone tissue by applying a low level alternating current signal directly to the patient's skin. A crystal oscillator, a binary divider chain and digital logic gates are used to generate the desired waveforms that reproduce the natural electrical characteristics found in bone tissue needed for stimulating bone growth and treating osteoporosis. The device, powered by a battery, contains a switch allowing selection of the correct waveform for bone growth stimulation or osteoporosis treatment so that, when attached to the skin of the patient using standard skin contact electrodes, the correct signal is communicated to the underlying bone structures.

  16. Digital electronic bone growth stimulator

    Energy Technology Data Exchange (ETDEWEB)

    Kronberg, J.W.

    1995-05-09

    A device is described for stimulating bone tissue by applying a low level alternating current signal directly to the patient`s skin. A crystal oscillator, a binary divider chain and digital logic gates are used to generate the desired waveforms that reproduce the natural electrical characteristics found in bone tissue needed for stimulating bone growth and treating osteoporosis. The device, powered by a battery, contains a switch allowing selection of the correct waveform for bone growth stimulation or osteoporosis treatment so that, when attached to the skin of the patient using standard skin contact electrodes, the correct signal is communicated to the underlying bone structures. 5 figs.

  17. Electrical stimulation in exercise training

    Science.gov (United States)

    Kroll, Walter

    1994-01-01

    Electrical stimulation has a long history of use in medicine dating back to 46 A.D. when the Roman physician Largus found the electrical discharge of torpedo fishes useful in the treatment of pain produced by headache and gout. A rival Greek physician, Dioscorides, discounted the value of the torpedo fish for headache relief but did recommend its use in the treatment of hemorrhoids. In 1745, the Leyden jar and various sized electrostatic generators were used to treat angina pectoris, epilepsy, hemiplegia, kidney stones, and sciatica. Benjamin Franklin used an electrical device to treat successfully a young woman suffering from convulsive fits. In the late 1800's battery powered hydroelectric baths were used to treat chronic inflammation of the uterus while electrified athletic supporters were advertised for the treatment of male problems. Fortunately, such an amusing early history of the simple beginnings of electrical stimulation did not prevent eventual development of a variety of useful therapeutic and rehabilitative applications of electrical stimulation. Over the centuries electrical stimulation has survived as a modality in the treatment of various medical disorders with its primary application being in the rehabilitation area. Recently, a surge of new interest in electrical stimulation has been kindled by the work of a Russian sport scientist who reported remarkable muscle strength and endurance improvements in elite athletes. Yakov Kots reported his research on electric stimulation and strength improvements in 1977 at a Canadian-Soviet Exchange Symposium held at Concordia University in Montreal. Since then an explosion of new studies has been seen in both sport science and in medicine. Based upon the reported works of Kots and the present surge of new investigations, one could be misled as to the origin of electrical stimulation as a technique to increase muscle strength. As a matter of fact, electric stimulation has been used as a technique to improve

  18. Neural stimulation and recording electrodes.

    Science.gov (United States)

    Cogan, Stuart F

    2008-01-01

    Electrical stimulation of nerve tissue and recording of neural electrical activity are the basis of emerging prostheses and treatments for spinal cord injury, stroke, sensory deficits, and neurological disorders. An understanding of the electrochemical mechanisms underlying the behavior of neural stimulation and recording electrodes is important for the development of chronically implanted devices, particularly those employing large numbers of microelectrodes. For stimulation, materials that support charge injection by capacitive and faradaic mechanisms are available. These include titanium nitride, platinum, and iridium oxide, each with certain advantages and limitations. The use of charge-balanced waveforms and maximum electrochemical potential excursions as criteria for reversible charge injection with these electrode materials are described and critiqued. Techniques for characterizing electrochemical properties relevant to stimulation and recording are described with examples of differences in the in vitro and in vivo response of electrodes.

  19. Transcranial Magnetic Stimulation for Schizophrenia

    National Research Council Canada - National Science Library

    Dougall, Nadine; Maayan, Nicola; Soares-Weiser, Karla; McDermott, Lisa M; McIntosh, Andrew

    2015-01-01

    .... One proposed alternative to drug treatments is transcranial magnetic stimulation (TMS). To date, many research trials to assess effectiveness of TMS for people with symptoms of schizophrenia have been conducted worldwide...

  20. Magnetic Brain Stimulation in ADHD

    OpenAIRE

    2001-01-01

    Transcranial magnetic brain stimulation was performed in 27 children and adolescents, aged 4 to 18 years, with ADHD in the Services of Pediatric Neurology and Clinical Neurophysiology, Miguel Servet Hospital, Zaragoza, Spain.

  1. Transcranial electrical stimulation: An introduction

    CERN Document Server

    Tarazona, Carlos G; Chávez, Laura; Andrade, Sebastián

    2015-01-01

    The main objective of the electrical stimulation of the brain is to generate action potentials from the application of electromagnetic fields. Among the available techniques, transcranial electrical stimulation (TES) represents a popular method of administration that has the advantage of being non-invasive and economically more affordable. This article aims to briefly introduce the reader into the understanding of TES in terms of the physics involved as well as for some of the relevant results of studies applying this technique.

  2. Deep Brain Stimulation for Parkinson's Disease

    Science.gov (United States)

    ... You are here Home » Disorders » All Disorders Deep Brain Stimulation for Parkinson's Disease Information Page Deep Brain Stimulation for Parkinson's Disease Information Page Search Disorders ...

  3. Neuroprotection trek--the next generation: neuromodulation I. Techniques--deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation

    Science.gov (United States)

    Andrews, Russell J.

    2003-01-01

    Neuromodulation denotes controlled electrical stimulation of the central or peripheral nervous system. The three forms of neuromodulation described in this paper-deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation-were chosen primarily for their demonstrated or potential clinical usefulness. Deep brain stimulation is a completely implanted technique for improving movement disorders, such as Parkinson's disease, by very focal electrical stimulation of the brain-a technique that employs well-established hardware (electrode and pulse generator/battery). Vagus nerve stimulation is similar to deep brain stimulation in being well-established (for the treatment of refractory epilepsy), completely implanted, and having hardware that can be considered standard at the present time. Vagus nerve stimulation differs from deep brain stimulation, however, in that afferent stimulation of the vagus nerve results in diffuse effects on many regions throughout the brain. Although use of deep brain stimulation for applications beyond movement disorders will no doubt involve placing the stimulating electrode(s) in regions other than the thalamus, subthalamus, or globus pallidus, the use of vagus nerve stimulation for applications beyond epilepsy-for example, depression and eating disorders-is unlikely to require altering the hardware significantly (although stimulation protocols may differ). Transcranial magnetic stimulation is an example of an external or non-implanted, intermittent (at least given the current state of the hardware) stimulation technique, the clinical value of which for neuromodulation and neuroprotection remains to be determined.

  4. Electrical stimulation and motor recovery.

    Science.gov (United States)

    Young, Wise

    2015-01-01

    In recent years, several investigators have successfully regenerated axons in animal spinal cords without locomotor recovery. One explanation is that the animals were not trained to use the regenerated connections. Intensive locomotor training improves walking recovery after spinal cord injury (SCI) in people, and >90% of people with incomplete SCI recover walking with training. Although the optimal timing, duration, intensity, and type of locomotor training are still controversial, many investigators have reported beneficial effects of training on locomotor function. The mechanisms by which training improves recovery are not clear, but an attractive theory is available. In 1949, Donald Hebb proposed a famous rule that has been paraphrased as "neurons that fire together, wire together." This rule provided a theoretical basis for a widely accepted theory that homosynaptic and heterosynaptic activity facilitate synaptic formation and consolidation. In addition, the lumbar spinal cord has a locomotor center, called the central pattern generator (CPG), which can be activated nonspecifically with electrical stimulation or neurotransmitters to produce walking. The CPG is an obvious target to reconnect after SCI. Stimulating motor cortex, spinal cord, or peripheral nerves can modulate lumbar spinal cord excitability. Motor cortex stimulation causes long-term changes in spinal reflexes and synapses, increases sprouting of the corticospinal tract, and restores skilled forelimb function in rats. Long used to treat chronic pain, motor cortex stimuli modify lumbar spinal network excitability and improve lower extremity motor scores in humans. Similarly, epidural spinal cord stimulation has long been used to treat pain and spasticity. Subthreshold epidural stimulation reduces the threshold for locomotor activity. In 2011, Harkema et al. reported lumbosacral epidural stimulation restores motor control in chronic motor complete patients. Peripheral nerve or functional electrical

  5. Perspectives on stimulated Brillouin scattering

    Science.gov (United States)

    Garmire, Elsa

    2017-01-01

    This collection of papers describes research that goes into detail on some of the more important issues in the physics of stimulated Brillouin scattering. This perspective describes the earliest years of the physics of stimulated Brillouin scattering, along with key developments that have led to this technically and physically rich field of today’s nonlinear optics. Stimulated Brillouin has a profound effect in optical fiber communications, initially discovered by its limit on the transmitted power. By controlling SBS in fibers and making use of its phase conjugation properties in both fibers and bulk media, a wide range of applications have been enabled. Today ring Brillouin lasers in fibers, whispering gallery modes and in photonic integrated circuits provide optical delay lines and switches, pulse shapers and components for increasingly complex and important optical systems.

  6. Enteral feeding without pancreatic stimulation

    DEFF Research Database (Denmark)

    Kaushik, Neeraj; Pietraszewski, Marie; Holst, Jens Juul

    2005-01-01

    OBJECTIVE: All forms of commonly practiced enteral feeding techniques stimulate pancreatic secretion, and only intravenous feeding avoids it. In this study, we explored the possibility of more distal enteral infusions of tube feeds to see whether activation of the ileal brake mechanism can result...... in enteral feeding without pancreatic stimulation, with particular reference to trypsin, because the avoidance of trypsin stimulation may optimize enteral feeding in acute pancreatitis. METHODS: The pancreatic secretory responses to feeding were studied in 36 healthy volunteers by standard double......-lumen duodenal perfusion/aspiration techniques over 6 hours. Subjects were assigned to no feeding (n = 7), duodenal feeding with a polymeric diet (n = 7) or low-fat elemental diet (n = 6), mid-distal jejunal feeding (n = 11), or intravenous feeding (n = 5). All diets provided 40 kcal/kg ideal body weight/d and 1...

  7. Deep brain stimulation: postoperative issues.

    Science.gov (United States)

    Deuschl, Günther; Herzog, Jan; Kleiner-Fisman, Galit; Kubu, Cynthia; Lozano, Andres M; Lyons, Kelly E; Rodriguez-Oroz, Maria C; Tamma, Filippo; Tröster, Alexander I; Vitek, Jerrold L; Volkmann, Jens; Voon, Valerie

    2006-06-01

    Numerous factors need to be taken into account when managing a patient with Parkinson's disease (PD) after deep brain stimulation (DBS). Questions such as when to begin programming, how to conduct a programming screen, how to assess the effects of programming, and how to titrate stimulation and medication for each of the targeted sites need to be addressed. Follow-up care should be determined, including patient adjustments of stimulation, timing of follow-up visits and telephone contact with the patient, and stimulation and medication conditions during the follow-up assessments. A management plan for problems that can arise after DBS such as weight gain, dyskinesia, axial symptoms, speech dysfunction, muscle contractions, paresthesia, eyelid, ocular and visual disturbances, and behavioral and cognitive problems should be developed. Long-term complications such as infection or erosion, loss of effect, intermittent stimulation, tolerance, and pain or discomfort can develop and need to be managed. Other factors that need consideration are social and job-related factors, development of dementia, general medical issues, and lifestyle changes. This report from the Consensus on Deep Brain Stimulation for Parkinson's Disease, a project commissioned by the Congress of Neurological Surgeons and the Movement Disorder Society, outlines answers to a series of questions developed to address all aspects of DBS postoperative management and decision-making with a systematic overview of the literature (until mid-2004) and by the expert opinion of the authors. The report has been endorsed by the Scientific Issues Committee of the Movement Disorder Society and the American Society of Stereotactic and Functional Neurosurgery.

  8. Trigeminovascular stimulation in conscious rats

    NARCIS (Netherlands)

    Kemper, RHA; Meijler, WJ; TerHorst, GJ

    1997-01-01

    INTRACISTERNAL infusion of capsaicin was used to induce intracranial trigeminovascular stimulation in conscious rats. Both behaviour and trigeminal nucleus caudalis c-fos expression were examined. Exploratory behaviour was dose-dependently reduced and different types of behaviours were induced with

  9. Activities to Stimulate Critical Thinking.

    Science.gov (United States)

    Haynes, Thomas B.; Schroeder, Connie

    1989-01-01

    Describes sample vocational activities that stimulate critical thinking: (1) setting up an accounting system (business education); (2) developing a marketing plan (marketing education); (3) developing a fertilizer application plan (agricultural education); (4) making the best purchase (home economics); (5) planning a repair/remodeling project…

  10. AUXIN STIMULATION OF ETHYLENE EVOLUTION

    Science.gov (United States)

    mechanism of auxin action on the enhancement of ethylene production is the formation of enzymes involved in ethylene biogenesis....The stimulation of ethylene production by auxin was inhibited by actinomycin D and other inhibitors of protein synthesis. It is concluded that the

  11. Orientation selective deep brain stimulation

    Science.gov (United States)

    Lehto, Lauri J.; Slopsema, Julia P.; Johnson, Matthew D.; Shatillo, Artem; Teplitzky, Benjamin A.; Utecht, Lynn; Adriany, Gregor; Mangia, Silvia; Sierra, Alejandra; Low, Walter C.; Gröhn, Olli; Michaeli, Shalom

    2017-02-01

    Objective. Target selectivity of deep brain stimulation (DBS) therapy is critical, as the precise locus and pattern of the stimulation dictates the degree to which desired treatment responses are achieved and adverse side effects are avoided. There is a clear clinical need to improve DBS technology beyond currently available stimulation steering and shaping approaches. We introduce orientation selective neural stimulation as a concept to increase the specificity of target selection in DBS. Approach. This concept, which involves orienting the electric field along an axonal pathway, was tested in the corpus callosum of the rat brain by freely controlling the direction of the electric field on a plane using a three-electrode bundle, and monitoring the response of the neurons using functional magnetic resonance imaging (fMRI). Computational models were developed to further analyze axonal excitability for varied electric field orientation. Main results. Our results demonstrated that the strongest fMRI response was observed when the electric field was oriented parallel to the axons, while almost no response was detected with the perpendicular orientation of the electric field relative to the primary fiber tract. These results were confirmed by computational models of the experimental paradigm quantifying the activation of radially distributed axons while varying the primary direction of the electric field. Significance. The described strategies identify a new course for selective neuromodulation paradigms in DBS based on axonal fiber orientation.

  12. Aversive Stimulation -- Criteria for Application.

    Science.gov (United States)

    O'Donnell, Patrick A.; Ohlson, Glenn A.

    Criteria for applying aversive stimulation with severely handicapped children are examined, and practical and ethical issues are considered. Factors seen to influence punishment outcomes include timing, intensity, and schedule of reinforcement. Suggested is the need for further research on the comparative effectiveness of positive and negative…

  13. Ovarian stimulation and embryo quality

    NARCIS (Netherlands)

    Baart, Esther; Macklon, Nick S.; Fauser, Bart J. C. M.

    2009-01-01

    To Study the effects of different ovarian stimulation approaches on oocyte and embryo quality, it is imperative to assess embryo quality with a reliable and objective method. Embryos rated as high quality by standardized morphological assessment are associated with higher implantation and pregnancy

  14. Stimulation of phagocytosis by sulforaphane

    Energy Technology Data Exchange (ETDEWEB)

    Suganuma, Hiroyuki, E-mail: hsuganu1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Fahey, Jed W., E-mail: jfahey@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Bryan, Kelley E., E-mail: kbryanm1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Healy, Zachary R., E-mail: zhealy1@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States); Talalay, Paul, E-mail: ptalalay@jhmi.edu [Lewis B. and Dorothy Cullman Cancer Chemoprotection Center, Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States)

    2011-02-04

    Research highlights: {yields} Sulforaphane stimulates the phagocytosis of RAW 264.7 macrophages under conditions of serum deprivation. {yields} This effect does not require Nrf2-dependent induction of phase 2 genes. {yields} Inactivation of macrophage migration inhibitory factor (MIF) by sulforaphane may be involved in stimulation of phagocytosis by sulforaphane. -- Abstract: Sulforaphane, a major isothiocyanate derived from cruciferous vegetables, protects living systems against electrophile toxicity, oxidative stress, inflammation, and radiation. A major protective mechanism is the induction of a network of endogenous cytoprotective (phase 2) genes that are regulated by transcription factor Nrf2. To obtain a more detailed understanding of the anti-inflammatory and immunomodulatory effects of sulforaphane, we evaluated its effect on the phagocytosis activity of RAW 264.7 murine macrophage-like cells by measuring the uptake of 2-{mu}m diameter polystyrene beads. Sulforaphane raised the phagocytosis activity of RAW 264.7 cells but only in the absence or presence of low concentrations (1%) of fetal bovine serum. Higher serum concentrations depressed phagocytosis and abolished its stimulation by sulforaphane. This stimulation did not depend on the induction of Nrf2-regulated genes since it occurred in peritoneal macrophages of nrf2{sup -/-} mice. Moreover, a potent triterpenoid inducer of Nrf2-dependent genes did not stimulate phagocytosis, whereas sulforaphane and another isothiocyanate (benzyl isothiocyanate) had comparable inducer potencies. It has been shown recently that sulforaphane is a potent and direct inactivator of macrophage migration inhibitory factor (MIF), an inflammatory cytokine. Moreover, the addition of recombinant MIF to RAW 264.7 cells attenuated phagocytosis, but sulforaphane-inactivated MIF did not affect phagocytosis. The inactivation of MIF may therefore be involved in the phagocytosis-enhancing activity of sulforaphane.

  15. Electrical stimulation of experimental nonunions

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, R.R.; Luethi, U.; Dueland, R.T.; Perren, S.M.

    Hypertrophic and oligotrophic nonunions were prepared by resection of a portion of the proximal ulna in dogs. In the hypertrophic nonunions, 20 muamps of direct current for eight weeks produced an increase in bone formation compared to the opposite control limb by radiography, photometry, point counting of new bone, and growth rate by sequential fluorochrome labeling and the dynamic uptake of 99mTc-labeled methylene disphosphonate. Oligotrophic nonunions were treated by plating and aspiration grafting in addition to direct-current stimulation. Ony the point counting of new bone showed a significant increase in bone formation with stimulation. Sequential fluorochrome labeling demonstrated that the new bone was laid down on existing bone and not primarily adjacent to the cathode within the fibrous nonunion. This finding supports the cell-mediated rather than physicochemical effect of electrostimulation.

  16. Somato stimulation and acupuncture therapy.

    Science.gov (United States)

    Zhao, Jing-Jun; Rong, Pei-Jing; Shi, Li; Ben, Hui; Zhu, Bing

    2016-05-01

    Acupuncture is an oldest somato stimulus medical technique. As the most representative peripheral nerve stimulation therapy, it has a complete system of theory and application and is applicable to a large population. This paper expounds the bionic origins of acupuncture and analyzes the physiological mechanism by which acupuncture works. For living creatures, functionally sound viscera and effective endurance of pain are essential for survival. This paper discusses the way in which acupuncture increases the pain threshold of living creatures and the underlying mechanism from the perspective of bionics. Acupuncture can also help to adjust visceral functions and works most effectively in facilitating the process of digestion and restraining visceral pain. This paper makes an in-depth overview of peripheral nerve stimulation therapy represented by acupuncture. We look forward to the revival of acupuncture, a long-standing somato stimulus medicine, in the modern medical systems.

  17. Stimulated Superconductivity at Strong Coupling

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Ning; Dong, Xi; Silverstein, Eva; Torroba, Gonzalo; /Stanford U., ITP /Stanford U., Phys. Dept. /SLAC

    2011-08-12

    Stimulating a system with time dependent sources can enhance instabilities, thus increasing the critical temperature at which the system transitions to interesting low-temperature phases such as superconductivity or superfluidity. After reviewing this phenomenon in non-equilibrium BCS theory (and its marginal fermi liquid generalization) we analyze the effect in holographic superconductors. We exhibit a simple regime in which the transition temperature increases parametrically as we increase the frequency of the time-dependent source.

  18. Tactile Stimulation and Consumer Response.

    OpenAIRE

    Hornik, Jacob

    1992-01-01

    Tactile behavior is a basic communication form as well as an expression of interpersonal involvement. This article presents three studies offering evidence for the positive role of casual interpersonal touch on consumer behavior. More specifically, it provides initial support for the view that tactile stimulation in various consumer behavior situations enhances the positive feeling for and evaluation of both the external stimuli and the touching source. Further, customers touched by a request...

  19. Movement disorders induced by deep brain stimulation.

    Science.gov (United States)

    Baizabal-Carvallo, José Fidel; Jankovic, Joseph

    2016-04-01

    Deep brain stimulation represents a major advance in the treatment of several types of movement disorders. However, during stimulation new movement disorders may emerge, thus limiting the positive effects of this therapy. These movement disorders may be induced by: 1) stimulation of the targeted nucleus, 2) stimulation of surrounding tracts and nuclei, and 3) as a result of dose adjustment of accompanying medications, such as reduction of dopaminergic drugs in patients with Parkinson's disease. Various dyskinesias, blepharospasm, and apraxia of eyelid opening have been described mainly with subthalamic nucleus stimulation, whereas hypokinesia and freezing of gait have been observed with stimulation of the globus pallidus internus. Other deep brain stimulation-related movement disorders include dyskinesias associated with stimulation of the globus pallidus externus and ataxic gait as a side effect of chronic bilateral stimulation of the ventral intermediate nucleus of thalamus. These movement disorders are generally reversible and usually resolved once the stimulation is reduced or turned off. This, however, typically leads to loss of benefit of the underlying movement disorder which can be re-gained by using different contacts, changing targets or stimulation parameters, and adjusting pharmacological therapy. New and innovative emerging technologies and stimulation techniques may help to prevent or overcome the various deep brain stimulation-induced movement disorders. In this review we aim to describe the clinical features, frequency, pathophysiology, and strategies for treatment of these iatrogenic movement disorders.

  20. Stimulating parameters and de-synchronization in vagus nerve stimulation therapy for epilepsy

    Science.gov (United States)

    Li, Y.-L.; Chen, Z.-Y.; Ma, J.; Feng, W.-J.

    2008-02-01

    The influence of the stimulation parameters on the de-synchronization of small world Hindmarsh-Rose (H-R) neural network is numerically investigated in the vagus nerve stimulation therapy for epilepsy. The simulation shows that synchronization evolves into de-synchronization when a part of neurons (about 10 percent) is stimulated with a pulse current signal. The network de-synchronization appears to be sensitive to the stimulation parameters. For the case of the same stimulation intensity, those weakly coupled networks reach de-synchronization more easily than strongly coupled networks. There exist an optimal stimulation interval and period of continuous stimulation time when other stimulation parameters remain invariable.

  1. Stimulating parameters and de-synchronization in vagus nerve stimulation therapy for epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y-L; Ma, J; Feng, W-J [Institute of Theoretical Physics, Lanzhou University of Technology, 287 Langongping Road, Lanzhou 730050 (China); Chen, Z-Y [Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720 (United States)], E-mail: hyperchaos@163.com, E-mail: liyl20031@126.com, E-mail: chen_zhao_yang@yahoo.com

    2008-02-15

    The influence of the stimulation parameters on the de-synchronization of small world Hindmarsh-Rose (H-R) neural network is numerically investigated in the vagus nerve stimulation therapy for epilepsy. The simulation shows that synchronization evolves into de-synchronization when a part of neurons (about 10 percent) is stimulated with a pulse current signal. The network de-synchronization appears to be sensitive to the stimulation parameters. For the case of the same stimulation intensity, those weakly coupled networks reach de-synchronization more easily than strongly coupled networks. There exist an optimal stimulation interval and period of continuous stimulation time when other stimulation parameters remain invariable.

  2. Gastric stimulation for weight loss

    Institute of Scientific and Technical Information of China (English)

    Meir Mizrahi; Ami Ben Ya'acov; Yaron Ilan

    2012-01-01

    The prevalence of obesity is growing to epidemic proportions,and there is clearly a need for minimally invasive therapies with few adverse effects that allow for sustained weight loss.Behavior and lifestyle therapy are safe treatments for obesity in the short term,but the durability of the weight loss is limited.Although promising obesity drugs are in development,the currently available drugs lack efficacy or have unacceptable side effects.Surgery leads to long-term weight loss,but it is associated with morbidity and mortality.Gastric electrical stimulation (GES) has received increasing attention as a potential tool for treating obesity and gastrointestinal dysmotility disorders.GES is a promising,minimally invasive,safe,and effective method for treating obesity.External gastric pacing is aimed at alteration of the motility of the gastrointestinal tract in a way that will alter absorption due to alteration of transit time.In addition,data from animal models and preliminary data from human trials suggest a role for the gut-brain axis in the mechanism of GES.This may involve alteration of secretion of hormones associated with hunger or satiety.Patient selection for gastric stimulation therapy seems to be an important determinant of the treatment's outcome.Here,we review the current status,potential mechanisms of action,and possible future applications of gastric stimulation for obesity.

  3. Stimulation of Eryptosis by Cryptotanshinone

    Directory of Open Access Journals (Sweden)

    Rosi Bissinger

    2014-07-01

    Full Text Available Background/Aims: Cryptotanshinone, a component of Salvia miltiorrhiza Bunge roots, may trigger suicidal death or apoptosis of tumor cells and has thus been recommended for the prevention and treatment of malignancy. On the other hand, Cryptotanshinone has been shown to counteract apoptosis of neurons and hepatocytes. Similar to apoptosis of nucleated cells, erythrocytes may enter eryptosis, a suicidal death characterized by cell shrinkage and phosphatidylserine translocation to the erythrocyte surface. Eryptosis may be triggered by increase of cytosolic Ca2+-activity ([Ca2+]i. The present study explored whether Cryptotanshinone stimulates eryptosis. Methods: Forward scatter was taken as measure of cell volume, annexin V binding for identification of phosphatidylserine-exposing erythrocytes and Fluo3-fluorescence for determination of [Ca2+]i. Results: A 48 h exposure of human erythrocytes to Cryptotanshinone (10 µM was followed by significant decrease of forward scatter, significant increase of the percentage annexin-V-binding cells and significant increase of [Ca2+]i. The effect of Cryptotanshinone (1 µM on annexin-V-binding was virtually abrogated by removal of extracellular Ca2+. Conclusion: Cryptotanshinone is a powerful stimulator of suicidal erythrocyte death or eryptosis, which is effective mainly, if not exclusively, by stimulation of Ca2+ entry.

  4. Gastric stimulation for weight loss

    Science.gov (United States)

    Mizrahi, Meir; Ben Ya'acov, Ami; Ilan, Yaron

    2012-01-01

    The prevalence of obesity is growing to epidemic proportions, and there is clearly a need for minimally invasive therapies with few adverse effects that allow for sustained weight loss. Behavior and lifestyle therapy are safe treatments for obesity in the short term, but the durability of the weight loss is limited. Although promising obesity drugs are in development, the currently available drugs lack efficacy or have unacceptable side effects. Surgery leads to long-term weight loss, but it is associated with morbidity and mortality. Gastric electrical stimulation (GES) has received increasing attention as a potential tool for treating obesity and gastrointestinal dysmotility disorders. GES is a promising, minimally invasive, safe, and effective method for treating obesity. External gastric pacing is aimed at alteration of the motility of the gastrointestinal tract in a way that will alter absorption due to alteration of transit time. In addition, data from animal models and preliminary data from human trials suggest a role for the gut-brain axis in the mechanism of GES. This may involve alteration of secretion of hormones associated with hunger or satiety. Patient selection for gastric stimulation therapy seems to be an important determinant of the treatment’s outcome. Here, we review the current status, potential mechanisms of action, and possible future applications of gastric stimulation for obesity. PMID:22654422

  5. Neuromuscular electrical stimulation for skeletal muscle function.

    Science.gov (United States)

    Doucet, Barbara M; Lam, Amy; Griffin, Lisa

    2012-06-01

    Lack of neural innervation due to neurological damage renders muscle unable to produce force. Use of electrical stimulation is a medium in which investigators have tried to find a way to restore movement and the ability to perform activities of daily living. Different methods of applying electrical current to modify neuromuscular activity are electrical stimulation (ES), neuromuscular electrical stimulation (NMES), transcutaneous electrical nerve stimulation (TENS), and functional electrical stimulation (FES). This review covers the aspects of electrical stimulation used for rehabilitation and functional purposes. Discussed are the various parameters of electrical stimulation, including frequency, pulse width/duration, duty cycle, intensity/amplitude, ramp time, pulse pattern, program duration, program frequency, and muscle group activated, and how they affect fatigue in the stimulated muscle.

  6. Vagus Nerve Stimulation for Treating Epilepsy

    Science.gov (United States)

    ... Evidence-based Guideline for PATIENTS and their FAMILIES VAGUS NERVE STIMULATION FOR TREATING EPILEPSY This information sheet is provided to help you understand how vagus nerve stimulation (VNS) may help treat epilepsy. The American ...

  7. Electrical stimulation for epilepsy: stimulation of hippocampal foci.

    Science.gov (United States)

    Velasco, F; Velasco, M; Velasco, A L; Menez, D; Rocha, L

    2001-01-01

    Subacute and chronic continuous electrical stimulation at the epileptic focus in the hippocampus or parahippocampal cortex at 130 Hz, 0.21-1.0 ms, 2.5-3.5 V (about 200-300 microA) induces a decrease in focal EEG epileptic interictal activity and also in the occurrence of clinical seizures. This may represent an alternative for the treatment of temporal lobe seizures originated in bilateral independent temporal lobe foci or occurring in patients where one is uncertain whether memory deficit might result from ablative procedures.

  8. A Chip for an Implantable Neural Stimulator

    DEFF Research Database (Denmark)

    Gudnason, Gunnar; Bruun, Erik; Haugland, Morten

    2000-01-01

    transmission to the stimulator passes through a 5 MHz inductive link. From the signals transmitted to the stimulator, the chip is able to generate charge-balanced current pulses with a controllable length up to 256 µs and an amplitude up to 2 mA, for stimulation of nerve fibers. The quiescent current...

  9. Geothermal Reservoir Well Stimulation Program: technology transfer

    Energy Technology Data Exchange (ETDEWEB)

    1980-05-01

    Each of the following types of well stimulation techniques are summarized and explained: hydraulic fracturing; thermal; mechanical, jetting, and drainhole drilling; explosive and implosive; and injection methods. Current stimulation techniques, stimulation techniques for geothermal wells, areas of needed investigation, and engineering calculations for various techniques. (MHR)

  10. Vomiting Center reanalyzed: An electrical stimulation study

    Science.gov (United States)

    Miller, A. D.; Wilson, V. J.

    1982-01-01

    Electrical stimulation of the brainstem of 15 decerebrate cats produced stimulus-bound vomiting in only 4 animals. Vomiting was reproducible in only one cat. Effective stimulating sites were located in the solitary tract and reticular formation. Restricted localization of a vomiting center, stimulation of which evoked readily reproducible results, could not be obtained.

  11. Noninvasive cortical stimulation with transcranial direct current stimulation in Parkinson's disease.

    Science.gov (United States)

    Fregni, Felipe; Boggio, Paulo S; Santos, Marcelo C; Lima, Moises; Vieira, Adriana L; Rigonatti, Sergio P; Silva, M Teresa A; Barbosa, Egberto R; Nitsche, Michael A; Pascual-Leone, Alvaro

    2006-10-01

    Electrical stimulation of deep brain structures, such as globus pallidus and subthalamic nucleus, is widely accepted as a therapeutic tool for patients with Parkinson's disease (PD). Cortical stimulation either with epidural implanted electrodes or repetitive transcranial magnetic stimulation can be associated with motor function enhancement in PD. We aimed to study the effects of another noninvasive technique of cortical brain stimulation, transcranial direct current stimulation (tDCS), on motor function and motor-evoked potential (MEP) characteristics of PD patients. We tested tDCS using different electrode montages [anodal stimulation of primary motor cortex (M1), cathodal stimulation of M1, anodal stimulation of dorsolateral prefrontal cortex (DLPFC), and sham-stimulation] and evaluated the effects on motor function--as indexed by Unified Parkinson's Disease Rating Scale (UPDRS), simple reaction time (sRT) and Purdue Pegboard test--and on corticospinal motor excitability (MEP characteristics). All experiments were performed in a double-blinded manner. Anodal stimulation of M1 was associated with a significant improvement of motor function compared to sham-stimulation in the UPDRS (P stimulation of M1 or anodal stimulation of DLPFC. Furthermore, whereas anodal stimulation of M1 significantly increased MEP amplitude and area, cathodal stimulation of M1 significantly decreased them. There was a trend toward a significant correlation between motor function improvement after M1 anodal-tDCS and MEP area increase. These results confirm and extend the notion that cortical brain stimulation might improve motor function in patients with PD.

  12. Tapering Enhanced Stimulated Superradiant Amplification

    CERN Document Server

    Duris, Joseph; Musumeci, Pietro

    2014-01-01

    High conversion efficiency between electrical and optical power is highly desirable both for high peak and high average power radiation sources. In this paper we discuss a new mechanism based on stimulated superradiant emission in a strongly tapered undulator whereby an optimal undulator tapering is calculated by dynamically matching the resonant energy variation to the ponderomotive decelerating gradient. The method has the potential to allow the extraction of a large fraction (~50%) of power from a relativistic electron beam and convert it into coherent narrow-band tunable radiation, and shows a clear path to very high average power radiation sources.

  13. Stimulated Brillouin Scattering Microscopic Imaging.

    Science.gov (United States)

    Ballmann, Charles W; Thompson, Jonathan V; Traverso, Andrew J; Meng, Zhaokai; Scully, Marlan O; Yakovlev, Vladislav V

    2015-01-01

    Two-dimensional stimulated Brillouin scattering microscopy is demonstrated for the first time using low power continuous-wave lasers tunable around 780 nm. Spontaneous Brillouin spectroscopy has much potential for probing viscoelastic properties remotely and non-invasively on a microscopic scale. Nonlinear Brillouin scattering spectroscopy and microscopy may provide a way to tremendously accelerate the data aquisition and improve spatial resolution. This general imaging setup can be easily adapted for specific applications in biology and material science. The low power and optical wavelengths in the water transparency window used in this setup provide a powerful bioimaging technique for probing the mechanical properties of hard and soft tissue.

  14. Stimulated Brillouin Scattering Microscopic Imaging

    Science.gov (United States)

    Ballmann, Charles W.; Thompson, Jonathan V.; Traverso, Andrew J.; Meng, Zhaokai; Scully, Marlan O.; Yakovlev, Vladislav V.

    2015-12-01

    Two-dimensional stimulated Brillouin scattering microscopy is demonstrated for the first time using low power continuous-wave lasers tunable around 780 nm. Spontaneous Brillouin spectroscopy has much potential for probing viscoelastic properties remotely and non-invasively on a microscopic scale. Nonlinear Brillouin scattering spectroscopy and microscopy may provide a way to tremendously accelerate the data aquisition and improve spatial resolution. This general imaging setup can be easily adapted for specific applications in biology and material science. The low power and optical wavelengths in the water transparency window used in this setup provide a powerful bioimaging technique for probing the mechanical properties of hard and soft tissue.

  15. Transverse stimulated Raman scattering in KDP

    Energy Technology Data Exchange (ETDEWEB)

    Barker, C.E.; Sacks, R.A.; Wonterghem, B.M. Van; Caird, J.A.; Murray, J.R.; Campbell, J.H.; Kyle, K.; Ehrlich, R.E.; Nielsen, N.D.

    1995-09-12

    Optical components of large-aperture, high irradiance and high fluence lasers can experience significant levels of stimulated scattering along their transverse dimensions. The authors have observed transverse stimulated Raman scattering in large aperture KDP crystals, and have measured the stimulated gain coefficient. With sufficiently high gain, transverse stimulated scattering can lead to energy loss from the main beam and, more importantly, optical damage in the components in which this scattering occurs. Thus transverse stimulated,scattering is of concern in large aperture fusion lasers such as Nova and Beamlet, which is a single-aperture, full-scale scientific prototype of the laser driver for the proposed National Ignition Facility.

  16. Field distribution of epidural electrical stimulation.

    Science.gov (United States)

    Xie, Xiaobo; Cui, Hong yan; Xu, Shengpu; Hu, Yong

    2013-11-01

    Epidural electrical stimulation has been applied in clinics for many years. However, there is still a concern about possible injury to spinal nerves. This study investigated electrical field and current density distribution during direct epidural electrical stimulation. Field distribution models were theoretically deduced, while the distribution of potentials and current were analyzed. The current density presented an increase of 70-80%, with one peak value ranging from -85° to 85° between the two stimulated poles. The effect of direct epidural electrical stimulation is mainly on local tissue surrounding the electrodes, concentrated around the two stimulated positions. © 2013 Elsevier Ltd. All rights reserved.

  17. Bubble stimulation efficiency of dinoflagellate bioluminescence.

    Science.gov (United States)

    Deane, Grant B; Stokes, M Dale; Latz, Michael I

    2016-02-01

    Dinoflagellate bioluminescence, a common source of bioluminescence in coastal waters, is stimulated by flow agitation. Although bubbles are anecdotally known to be stimulatory, the process has never been experimentally investigated. This study quantified the flash response of the bioluminescent dinoflagellate Lingulodinium polyedrum to stimulation by bubbles rising through still seawater. Cells were stimulated by isolated bubbles of 0.3-3 mm radii rising at their terminal velocity, and also by bubble clouds containing bubbles of 0.06-10 mm radii for different air flow rates. Stimulation efficiency, the proportion of cells producing a flash within the volume of water swept out by a rising bubble, decreased with decreasing bubble radius for radii less than approximately 1 mm. Bubbles smaller than a critical radius in the range 0.275-0.325 mm did not stimulate a flash response. The fraction of cells stimulated by bubble clouds was proportional to the volume of air in the bubble cloud, with lower stimulation levels observed for clouds with smaller bubbles. An empirical model for bubble cloud stimulation based on the isolated bubble observations successfully reproduced the observed stimulation by bubble clouds for low air flow rates. High air flow rates stimulated more light emission than expected, presumably because of additional fluid shear stress associated with collective buoyancy effects generated by the high air fraction bubble cloud. These results are relevant to bioluminescence stimulation by bubbles in two-phase flows, such as in ship wakes, breaking waves, and sparged bioreactors.

  18. High-frequency and brief-pulse stimulation pulses terminate cortical electrical stimulation-induced afterdischarges.

    Science.gov (United States)

    Ren, Zhi-Wei; Li, Yong-Jie; Yu, Tao; Ni, Duan-Yu; Zhang, Guo-Jun; Du, Wei; Piao, Yuan-Yuan; Zhou, Xiao-Xia

    2017-06-01

    Brief-pulse stimulation at 50 Hz has been shown to terminate afterdischarges observed in epilepsy patients. However, the optimal pulse stimulation parameters for terminating cortical electrical stimulation-induced afterdischarges remain unclear. In the present study, we examined the effects of different brief-pulse stimulation frequencies (5, 50 and 100 Hz) on cortical electrical stimulation-induced afterdischarges in 10 patients with refractory epilepsy. Results demonstrated that brief-pulse stimulation could terminate cortical electrical stimulation-induced afterdischarges in refractory epilepsy patients. In conclusion, (1) a brief-pulse stimulation was more effective when the afterdischarge did not extend to the surrounding brain area. (2) A higher brief-pulse stimulation frequency (especially 100 Hz) was more likely to terminate an afterdischarge. (3) A low current intensity of brief-pulse stimulation was more likely to terminate an afterdischarge.

  19. Optical stimulator for vision-based sensors

    DEFF Research Database (Denmark)

    Rössler, Dirk; Pedersen, David Arge Klevang; Benn, Mathias

    2014-01-01

    We have developed an optical stimulator system for vision-based sensors. The stimulator is an efficient tool for stimulating a camera during on-ground testing with scenes representative of spacecraft flights. Such scenes include starry sky, planetary objects, and other spacecraft. The optical...... precision and long-term stability. The system can be continuously used over several days. By facilitating a full camera including optics in the loop, the stimulator enables the more realistic simulation of flight maneuvers based on navigation cameras than pure computer simulations or camera stimulations...... stimulator is used as a test bench to simulate high-precision navigation by different types of camera systems that are used onboard spacecraft, planetary rovers, and for spacecraft rendezvous and proximity maneuvers. Careful hardware design and preoperational calibration of the stimulator result in high...

  20. Stimulated emission from NV centres in diamond

    CERN Document Server

    Jeske, Jan; McGuinness, Liam P; Reineck, Philip; Johnson, Brett C; McCallum, Jeffrey C; Jelezko, Fedor; Volz, Thomas; Cole, Jared H; Gibson, Brant C; Greentree, Andrew D

    2016-01-01

    Stimulated emission is the process fundamental to laser operation, thereby producing coherent photon output. Despite negatively-charged nitrogen-vacancy (NV$^-$) centres being discussed as a potential laser medium since the 1980's, there have been no definitive observations of stimulated emission from ensembles of NV$^-$ to date. Reasons for this lack of demonstration include the short excited state lifetime and the occurrence of photo-ionisation to the neutral charge state by light around the zero-phonon line. Here we show both theoretical and experimental evidence for stimulated emission from NV$^-$ states using light in the phonon-sidebands. Our system uses a continuous wave pump laser at 532 nm and a pulsed stimulating laser that is swept across the phononic sidebands of the NV$^-$. Optimal stimulated emission is demonstrated in the vicinity of the three-phonon line at 700 nm. Furthermore, we show the transition from stimulated emission to photoionisation as the stimulating laser wavelength is reduced fro...

  1. Braille line using electrical stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Puertas, A; Pures, P; Echenique, A M; Ensinck, J P Graffigna y G [Gabinete de TecnologIa Medica. Universidad N. de San Juan (Argentina)

    2007-11-15

    Conceived within the field of Rehabilitation Technologies for visually impaired persons, the present work aims at enabling the blind user to read written material by means of a tactile display. Once he is familiarized to operate this system, the user will be able to achieve greater performance in study, academic and job activities, thus achieving a rapid and easier social inclusion. The devise accepts any kind of text that is computer-loadable (documents, books, Internet information, and the like) which, through digital means, can be read as Braille text on the pad. This tactile display is composed of an electrodes platform that simulate, through stimulation the writing/reading Braille characters. In order to perceive said characters in similar way to the tactile feeling from paper material, the skin receptor of fingers are stimulated electrically so as to simulate the same pressure and depressions as those of the paper-based counterpart information. Once designed and developed, the display was tested with blind subjects, with relatively satisfactory results. As a continuing project, this prototype is currently being improved as regards.

  2. Braille line using electrical stimulation

    Science.gov (United States)

    Puertas, A.; Purés, P.; Echenique, A. M.; Ensinck, J. P. Graffigna y. G.

    2007-11-01

    Conceived within the field of Rehabilitation Technologies for visually impaired persons, the present work aims at enabling the blind user to read written material by means of a tactile display. Once he is familiarized to operate this system, the user will be able to achieve greater performance in study, academic and job activities, thus achieving a rapid and easier social inclusion. The devise accepts any kind of text that is computer-loadable (documents, books, Internet information, and the like) which, through digital means, can be read as Braille text on the pad. This tactile display is composed of an electrodes platform that simulate, through stimulation the writing/reading Braille characters. In order to perceive said characters in similar way to the tactile feeling from paper material, the skin receptor of fingers are stimulated electrically so as to simulate the same pressure and depressions as those of the paper-based counterpart information. Once designed and developed, the display was tested with blind subjects, with relatively satisfactory results. As a continuing project, this prototype is currently being improved as regards.

  3. Vagus nerve stimulation regulates hemostasis in swine.

    Science.gov (United States)

    Czura, Christopher J; Schultz, Arthur; Kaipel, Martin; Khadem, Anna; Huston, Jared M; Pavlov, Valentin A; Redl, Heinz; Tracey, Kevin J

    2010-06-01

    The central nervous system regulates peripheral immune responses via the vagus nerve, the primary neural component of the cholinergic anti-inflammatory pathway. Electrical stimulation of the vagus nerve suppresses proinflammatory cytokine release in response to endotoxin, I/R injury, and hypovolemic shock and protects against lethal hypotension. To determine the effect of vagus nerve stimulation on coagulation pathways, anesthetized pigs were subjected to partial ear resection before and after electrical vagus nerve stimulation. We observed that electrical vagus nerve stimulation significantly decreased bleeding time (pre-electrical vagus nerve stimulation = 1033 +/- 210 s versus post-electrical vagus nerve stimulation = 585 +/- 111 s; P vagus nerve stimulation = 48.4 +/- 6.8 mL versus post-electrical vagus nerve stimulation = 26.3 +/- 6.7 mL; P vagus nerve stimulation was independent of changes in heart rate or blood pressure and correlated with increased thrombin/antithrombin III complex generation in shed blood. These data indicate that electrical stimulation of the vagus nerve attenuates peripheral hemorrhage in a porcine model of soft tissue injury and that this protective effect is associated with increased coagulation factor activity.

  4. Multisensory stimulation in stroke rehabilitation

    Directory of Open Access Journals (Sweden)

    Barbro Birgitta Johansson

    2012-04-01

    Full Text Available The brain has a large capacity for automatic simultaneous processing and integration of sensory information. Combining information from different sensory modalities facilitates our ability to detect, discriminate, and recognize sensory stimuli, and learning is often optimal in a multisensory environment. Currently used multisensory stimulation methods in stroke rehabilitation include motor imagery, action observation, training with a mirror or in a virtual environment, or various kinds of music therapy. Several studies have shown positive effects been reported but to give general recommendation more studies are needed. Patient heterogeneity and the interactions of age, gender, genes and environment are discussed. Randomized controlled longitudinal trials starting earlier post stroke are needed. The advance in brain network science and neuroimaging enabling longitudinal studies of structural and functional networks are likely to have an important impact on patient selection for specific interventions in future stroke rehabilitation.

  5. Vestibular stimulation by magnetic fields

    Science.gov (United States)

    Ward, Bryan K.; Roberts, Dale C.; Della Santina, Charles C.; Carey, John P.; Zee, David S.

    2015-01-01

    Individuals working next to strong static magnetic fields occasionally report disorientation and vertigo. With the increasing strength of magnetic fields used for magnetic resonance imaging (MRI) studies, these reports have become more common. It was recently learned that humans, mice and zebrafish all demonstrate behaviors consistent with constant peripheral vestibular stimulation while inside a strong, static magnetic field. The proposed mechanism for this effect involves a Lorentz force resulting from the interaction of a strong static magnetic field with naturally occurring ionic currents flowing through the inner ear endolymph into vestibular hair cells. The resulting force within the endolymph is strong enough to displace the lateral semicircular canal cupula, inducing vertigo and the horizontal nystagmus seen in normal mice and in humans. This review explores the evidence for interactions of magnetic fields with the vestibular system. PMID:25735662

  6. Non-invasive neural stimulation

    Science.gov (United States)

    Tyler, William J.; Sanguinetti, Joseph L.; Fini, Maria; Hool, Nicholas

    2017-05-01

    Neurotechnologies for non-invasively interfacing with neural circuits have been evolving from those capable of sensing neural activity to those capable of restoring and enhancing human brain function. Generally referred to as non-invasive neural stimulation (NINS) methods, these neuromodulation approaches rely on electrical, magnetic, photonic, and acoustic or ultrasonic energy to influence nervous system activity, brain function, and behavior. Evidence that has been surmounting for decades shows that advanced neural engineering of NINS technologies will indeed transform the way humans treat diseases, interact with information, communicate, and learn. The physics underlying the ability of various NINS methods to modulate nervous system activity can be quite different from one another depending on the energy modality used as we briefly discuss. For members of commercial and defense industry sectors that have not traditionally engaged in neuroscience research and development, the science, engineering and technology required to advance NINS methods beyond the state-of-the-art presents tremendous opportunities. Within the past few years alone there have been large increases in global investments made by federal agencies, foundations, private investors and multinational corporations to develop advanced applications of NINS technologies. Driven by these efforts NINS methods and devices have recently been introduced to mass markets via the consumer electronics industry. Further, NINS continues to be explored in a growing number of defense applications focused on enhancing human dimensions. The present paper provides a brief introduction to the field of non-invasive neural stimulation by highlighting some of the more common methods in use or under current development today.

  7. Transcranial electrical stimulation accelerates human sleep homeostasis.

    Directory of Open Access Journals (Sweden)

    Davide Reato

    Full Text Available The sleeping brain exhibits characteristic slow-wave activity which decays over the course of the night. This decay is thought to result from homeostatic synaptic downscaling. Transcranial electrical stimulation can entrain slow-wave oscillations (SWO in the human electro-encephalogram (EEG. A computational model of the underlying mechanism predicts that firing rates are predominantly increased during stimulation. Assuming that synaptic homeostasis is driven by average firing rates, we expected an acceleration of synaptic downscaling during stimulation, which is compensated by a reduced drive after stimulation. We show that 25 minutes of transcranial electrical stimulation, as predicted, reduced the decay of SWO in the remainder of the night. Anatomically accurate simulations of the field intensities on human cortex precisely matched the effect size in different EEG electrodes. Together these results suggest a mechanistic link between electrical stimulation and accelerated synaptic homeostasis in human sleep.

  8. Consensus paper: combining transcranial stimulation with neuroimaging

    DEFF Research Database (Denmark)

    Siebner, Hartwig R; Bergmann, Til O; Bestmann, Sven

    2009-01-01

    In the last decade, combined transcranial magnetic stimulation (TMS)-neuroimaging studies have greatly stimulated research in the field of TMS and neuroimaging. Here, we review how TMS can be combined with various neuroimaging techniques to investigate human brain function. When applied during...... neuroimaging (online approach), TMS can be used to test how focal cortex stimulation acutely modifies the activity and connectivity in the stimulated neuronal circuits. TMS and neuroimaging can also be separated in time (offline approach). A conditioning session of repetitive TMS (rTMS) may be used to induce...... information obtained by neuroimaging can be used to define the optimal site and time point of stimulation in a subsequent experiment in which TMS is used to probe the functional contribution of the stimulated area to a specific task. In this review, we first address some general methodologic issues that need...

  9. Bursting behaviours in cascaded stimulated Brillouin scattering

    Institute of Scientific and Technical Information of China (English)

    Liu Zhan-Jun; He Xian-Tu; Zheng Chun-Yang; Wang Yu-Gang

    2012-01-01

    Stimulated Brillouin scattering is studied by numerically solving the Vlasov-Maxwell system.A cascade of stimulated Brillouin scattering can occur when a linearly polarized laser pulse propagates in a plasma.It is found that a stimulated Brillouin scattering cascade can reduce the scattering and increase the transmission of light,as well as introduce a bursting behaviour in the evolution of the laser-plasma interaction.The bursting time in the reflectivity is found to be less than half the ion acoustic period.The ion temperature can affect the stimulated Brillouin scattering cascade,which can repeat several times at low ion temperatures and can be completely eliminated at high ion temperatures.For stimulated Brillouin scattering saturation,higher-harmonic generation and wave-wave interaction of the excited ion acoustic waves can restrict the amplitude of the latter.In addition,stimulated Brillouin scattering cascade can restrict the amplitude of the scattered light.

  10. Mimicking muscle activity with electrical stimulation

    Science.gov (United States)

    Johnson, Lise A.; Fuglevand, Andrew J.

    2011-02-01

    Functional electrical stimulation is a rehabilitation technology that can restore some degree of motor function in individuals who have sustained a spinal cord injury or stroke. One way to identify the spatio-temporal patterns of muscle stimulation needed to elicit complex upper limb movements is to use electromyographic (EMG) activity recorded from able-bodied subjects as a template for electrical stimulation. However, this requires a transfer function to convert the recorded (or predicted) EMG signals into an appropriate pattern of electrical stimulation. Here we develop a generalized transfer function that maps EMG activity into a stimulation pattern that modulates muscle output by varying both the pulse frequency and the pulse amplitude. We show that the stimulation patterns produced by this transfer function mimic the active state measured by EMG insofar as they reproduce with good fidelity the complex patterns of joint torque and joint displacement.

  11. ``Bloch wave'' modification of stimulated Raman by stimulated Brillouin scattering

    Science.gov (United States)

    Dodd, E. S.; Vu, H. X.; DuBois, D. F.; Bezzerides, B.

    2013-03-01

    Using the reduced-description particle-in-cell (RPIC) method, we study the coupling of backward stimulated Raman scattering (BSRS) and backward stimulated Brillouin scattering (BSBS) in regimes where the reflectivity involves the nonlinear behavior of particles trapped in the daughter plasma waves. The temporal envelope of a Langmuir wave (LW) obeys a Schrödinger equation where the potential is the periodic electron density fluctuation resulting from an ion-acoustic wave (IAW). The BSRS-driven LWs in this case have a Bloch wave structure and a modified dispersion due to the BSBS-driven spatially periodic IAW, which includes frequency band gaps at kLW˜kIAW/2˜k0 (kLW, kIAW, and k0 are the wave number of the LW, IAW, and incident pump electromagnetic wave, respectively). This band structure and the associated Bloch wave harmonic components are distinctly observed in RPIC calculations of the electron density fluctuation spectra and this structure may be observable in Thomson scatter. Bloch wave components grow up in the LW spectrum, and are not the result of isolated BSRS. Self-Thomson scattered light from these Bloch wave components can have forward scattering components. The distortion of the LW dispersion curve implies that the usual relationship connecting the frequency shift of the BSRS-scattered light and the density of origin of this light may become inaccurate. The modified LW frequency results in a time-dependent frequency shift that increases as the IAW grows, detunes the BSRS frequency matching condition, and reduces BSRS growth. A dependence of the BSRS reflectivity on the IAW Landau damping results because this damping determines the levels of IAWs. The time-dependent reflectivity in our simulations is characterized by bursts of sub-picosecond pulses of BSRS alternating with multi-ps pulses of BSBS, and BSRS is observed to decline precipitously as soon as SBS begins to grow from low levels. In strong BSBS regimes, the Bloch wave effects in BSRS are

  12. Communication between osteoblasts stimulated by electromagnetic fields

    Institute of Scientific and Technical Information of China (English)

    ZHANG JianBao; ZHANG XiaoJun

    2007-01-01

    Pulsed electromagnetic field can affect the proliferation of osteoblasts, but the mechanism is obscure yet. The communication between osteoblasts, isolated from calvaria bone of newborn SD rats and stimulated with the rectangular electromagnetic field of 15 Hz and 4 mT, was studied. Our results showed that the osteoblasts radiated a kind of light after they were stimulated with the electromagnetic field and it is the light that promotes the proliferation of un-stimulated osteoblasts.

  13. Motivation-stimulating Strategies in English Classes

    Institute of Scientific and Technical Information of China (English)

    李宁

    2015-01-01

    Motivation plays a very important role in foreign language learning. So it becomes worthwhile to study the teachers’ motivation-stimulating strategies. This article mainly discusses two strategies of stimulating the students’motivation in English classes:environment-providing strategies and goal-oriented strategies. They are hoped to provide some references for English teachers to stimulate the students’learning motivation in their classes.

  14. Transcranial Direct Current Stimulation in Stroke Recovery

    OpenAIRE

    Schlaug, Gottfried; Renga, Vijay; Nair, Dinesh

    2008-01-01

    TDCS - Transcranial Direct Current Stimulation - is an emerging technique of non-invasive brain stimulation that has been found useful in examining cortical function in normal subjects and in facilitating treatments of various neurological disorders. A better understanding of adaptive as well as maladaptive post-stroke neuroplasticity and its modulation through non-invasive brain stimulation has opened up experimental treatment options using TDCS for patients recovering from stroke. We will r...

  15. Optimal quantum cloning via stimulated emission

    CERN Document Server

    Simon, C; Zeilinger, Anton; Simon, Christoph; Weihs, Gregor; Zeilinger, Anton

    2000-01-01

    We show that optimal universal quantum cloning can be realized via stimulated emission. Universality of the cloning procedure is achieved by choosing systems that have appropriate symmetries. We first discuss a scheme based on stimulated emission in certain three-level-systems, e.g. atoms in a cavity. Then we present a way of realizing optimal universal cloning based on stimulated parametric down-conversion. This scheme also implements the optimal universal NOT operation.

  16. Electrical stimulation counteracts muscle decline in seniors

    National Research Council Canada - National Science Library

    Kern, Helmut; Barberi, Laura; Löfler, Stefan; Sbardella, Simona; Burggraf, Samantha; Fruhmann, Hannah; Carraro, Ugo; Mosole, Simone; Sarabon, Nejc; Vogelauer, Michael; Mayr, Winfried; Krenn, Matthias; Cvecka, Jan; Romanello, Vanina; Pietrangelo, Laura; Protasi, Feliciano; Sandri, Marco; Zampieri, Sandra; Musaro, Antonio

    2014-01-01

    .... We addressed whether electrical stimulation (ES) is an alternative intervention to improve muscle recovery and defined the molecular mechanism associated with improvement in muscle structure and function...

  17. Artifacts of Functional Electrical Stimulation on Electromyograph

    Institute of Scientific and Technical Information of China (English)

    DUAN Ren-quan; ZHANG Ding-guo

    2014-01-01

    The purpose of this study is to investigate different factors of the artifact in surface electromyography (EMG) signal caused by functional electrical stimulation (FES). The factors investigated include the size of stimulation electrode pads, the amplitude, frequency, and pulse width of the stimulation waveform and the detecting electrode points. We calculate the root mean square (RMS) of EMG signal to analyze the effect of these factors on the M-wave properties. The results indicate that the M-wave mainly depends on the stimulation amplitude and the distribution of detecting electrodes, but not on the other factors. This study can assist the reduction of artifact and the selection of detecting electrode points.

  18. Vagus nerve stimulation inhibits cortical spreading depression.

    Science.gov (United States)

    Chen, Shih-Pin; Ay, Ilknur; de Morais, Andreia Lopes; Qin, Tao; Zheng, Yi; Sadeghian, Homa; Oka, Fumiaki; Simon, Bruce; Eikermann-Haerter, Katharina; Ayata, Cenk

    2016-04-01

    Vagus nerve stimulation has recently been reported to improve symptoms of migraine. Cortical spreading depression is the electrophysiological event underlying migraine aura and is a trigger for headache. We tested whether vagus nerve stimulation inhibits cortical spreading depression to explain its antimigraine effect. Unilateral vagus nerve stimulation was delivered either noninvasively through the skin or directly by electrodes placed around the nerve. Systemic physiology was monitored throughout the study. Both noninvasive transcutaneous and invasive direct vagus nerve stimulations significantly suppressed spreading depression susceptibility in the occipital cortex in rats. The electrical stimulation threshold to evoke a spreading depression was elevated by more than 2-fold, the frequency of spreading depressions during continuous topical 1 M KCl was reduced by ∼40%, and propagation speed of spreading depression was reduced by ∼15%. This effect developed within 30 minutes after vagus nerve stimulation and persisted for more than 3 hours. Noninvasive transcutaneous vagus nerve stimulation was as efficacious as direct invasive vagus nerve stimulation, and the efficacy did not differ between the ipsilateral and contralateral hemispheres. Our findings provide a potential mechanism by which vagus nerve stimulation may be efficacious in migraine and suggest that susceptibility to spreading depression is a suitable platform to optimize its efficacy.

  19. Ovarian stimulation in patients with breast cancer.

    Science.gov (United States)

    Muñoz, Elkin; González, Naira; Muñoz, Luis; Aguilar, Jesús; Velasco, Juan A García

    2015-01-01

    Breast cancer is the most prevalent malignancy among women under 50. Improvements in diagnosis and treatment have yielded an important decrease in mortality in the last 20 years. In many cases, chemotherapy and radiotherapy develop side effects on the reproductive function. Therefore, before the anti-cancer treatment impairs fertility, clinicians should offer some techniques for fertility preservation for women planning motherhood in the future. In order to obtain more available oocytes for IVF, the ovary must be stimulated. New protocols which prevent exposure to increased estrogen during gonadotropin stimulation, measurements to avoid the delay in starting anti-cancer treatment or the outcome of ovarian stimulation have been addressed in this review. There is no evidence of association between ovarian stimulation and breast cancer. It seems that there are more relevant other confluent factors than ovarian stimulation. Factors that can modify the risk of breast cancer include: parity, age at full-term birth, age of menarche, and family history. There is an association between breast cancer and exogenous estrogen. Therefore, specific protocols to stimulate patients with breast cancer include anti-estrogen agents such as letrozole. By using letrozole plus recombinant follicular stimulating hormone, patients develop a multifollicular growth with only a mild increase in estradiol serum levels. Controlled ovarian stimulation (COS) takes around 10 days, and we discuss new strategies to start COS as soon as possible. Protocols starting during the luteal phase or after inducing the menses currently prevent a delay in starting ovarian stimulation. Patients with breast cancer have a poorer response to COS compared with patients without cancer who are stimulated with conventional protocols of gonadotropins. Although many centres offer fertility preservation and many patients undergo ovarian stimulation, there are not enough studies to evaluate the recurrence, breast cancer

  20. Hyperthermia stimulates HIV-1 replication.

    Directory of Open Access Journals (Sweden)

    Ferdinand Roesch

    Full Text Available HIV-infected individuals may experience fever episodes. Fever is an elevation of the body temperature accompanied by inflammation. It is usually beneficial for the host through enhancement of immunological defenses. In cultures, transient non-physiological heat shock (42-45°C and Heat Shock Proteins (HSPs modulate HIV-1 replication, through poorly defined mechanisms. The effect of physiological hyperthermia (38-40°C on HIV-1 infection has not been extensively investigated. Here, we show that culturing primary CD4+ T lymphocytes and cell lines at a fever-like temperature (39.5°C increased the efficiency of HIV-1 replication by 2 to 7 fold. Hyperthermia did not facilitate viral entry nor reverse transcription, but increased Tat transactivation of the LTR viral promoter. Hyperthermia also boosted HIV-1 reactivation in a model of latently-infected cells. By imaging HIV-1 transcription, we further show that Hsp90 co-localized with actively transcribing provirus, and this phenomenon was enhanced at 39.5°C. The Hsp90 inhibitor 17-AAG abrogated the increase of HIV-1 replication in hyperthermic cells. Altogether, our results indicate that fever may directly stimulate HIV-1 replication, in a process involving Hsp90 and facilitation of Tat-mediated LTR activity.

  1. Hyperthermia stimulates HIV-1 replication.

    Science.gov (United States)

    Roesch, Ferdinand; Meziane, Oussama; Kula, Anna; Nisole, Sébastien; Porrot, Françoise; Anderson, Ian; Mammano, Fabrizio; Fassati, Ariberto; Marcello, Alessandro; Benkirane, Monsef; Schwartz, Olivier

    2012-01-01

    HIV-infected individuals may experience fever episodes. Fever is an elevation of the body temperature accompanied by inflammation. It is usually beneficial for the host through enhancement of immunological defenses. In cultures, transient non-physiological heat shock (42-45°C) and Heat Shock Proteins (HSPs) modulate HIV-1 replication, through poorly defined mechanisms. The effect of physiological hyperthermia (38-40°C) on HIV-1 infection has not been extensively investigated. Here, we show that culturing primary CD4+ T lymphocytes and cell lines at a fever-like temperature (39.5°C) increased the efficiency of HIV-1 replication by 2 to 7 fold. Hyperthermia did not facilitate viral entry nor reverse transcription, but increased Tat transactivation of the LTR viral promoter. Hyperthermia also boosted HIV-1 reactivation in a model of latently-infected cells. By imaging HIV-1 transcription, we further show that Hsp90 co-localized with actively transcribing provirus, and this phenomenon was enhanced at 39.5°C. The Hsp90 inhibitor 17-AAG abrogated the increase of HIV-1 replication in hyperthermic cells. Altogether, our results indicate that fever may directly stimulate HIV-1 replication, in a process involving Hsp90 and facilitation of Tat-mediated LTR activity.

  2. Digital electronic bone growth stimulator

    Energy Technology Data Exchange (ETDEWEB)

    Kronberg, J.W.

    1993-01-01

    The present invention relates to the electrical treatment of biological tissue. In particular, the present invention discloses a device that produces discrete electrical pulse trains for treating osteoporosis and accelerating bone growth. According to its major aspects and broadly stated, the present invention consists of an electrical circuit configuration capable of generating Bassett-type waveforms shown with alternative signals provide for the treatment of either fractured bones or osteoporosis. The signal generator comprises a quartz clock, an oscillator circuit, a binary divider chain, and a plurality of simple, digital logic gates. Signals are delivered efficiently, with little or no distortion, and uniformly distributed throughout the area of injury. Perferably, power is furnished by widely available and inexpensive radio batteries, needing replacement only once in several days. The present invention can be affixed to a medical cast without a great increase in either weight or bulk. Also, the disclosed stimulator can be used to treat osteoporosis or to strengthen a healing bone after the cast has been removed by attaching the device to the patient`s skin or clothing.

  3. Electrical stimulation and muscle strengthening.

    Science.gov (United States)

    Dehail, P; Duclos, C; Barat, M

    2008-07-01

    To identify the effects of application methods and indications of direct muscle electrostimulation on strength gain. Literature review and analysis of articles from Medline database with the following entries: muscular or neuromuscular, electromyostimulation, electrical stimulation, strengthening, strength training, immobilization, muscle dystrophy, bed-rest, bed-bound, knee or hip surgery, postoperative phase, cachexia, sarcopenia, and their French equivalent. Because of its specific muscle recruitment order, different from that of voluntary contraction, direct muscle electrostimulation is theoretically a complementary tool for muscle strengthening. It can be used in healthy subjects and in several affections associated with muscle function loss. Its interest seems well-established for post-traumatic or postsurgery lower-limb immobilizations but too few controlled studies have clearly shown the overall benefits of its application in other indications. Whatever the indication, superimposed or combined electrostimulation techniques are generally more efficient than electrostimulation alone. Even though widely used, the level of evidence for the efficiency of electromyostimulation is still low. For strength gains, it yielded no higher benefits than traditional strengthening methods. Its interest should be tested in medical affections leading to major muscle deconditioning or in sarcopenia.

  4. [Deep brain stimulation and neuroethics].

    Science.gov (United States)

    Katayama, Yoichi; Fukaya, Chikashi

    2009-01-01

    The use of deep brain stimulation (DBS) for mental disorders has been discussed in Japan from the viewpoint of ethical problems. Trials of experimental therapies require a basis of sound scientific rationale. New standard therapy emerges from such trials through detailed analysis of the outcome and side effects. Long-suffering patients with intractable symptoms may desperately seek an experimental therapy even though it has not yet been accepted as standard therapy. The ethical committee of each institution evaluates the level of scientific rationale and the expected level of benefits on the bias of the reported data, and decides whether the patients can receive the experimental therapy. However, the use of DBS for mental disorders is not based on sound scientific rational, since the disease mechanisms involved are far from understood. The data reported from the previous trials are insufficient for assuring the satisfactory results for mental disoder patients. Most institutions in Japan do not accept such levels of scientific rationale and expected benefits. Furthermore, from the cultural perspective, strong skepticism exists in Japan with regard to surgical interventions for mental disorders. Such an attitude is unexpectedly in harmony with many of the subjects currently discussed in the field of neuroethics. For example, who has the right to control DBS? How does someone decide the level of control of mental function by DBS? These questions are related to the discussion on how human society is formed and how the ethics are decided by considering both scientific rationale and human society.

  5. Stimulating antitumor immunity with nanoparticles.

    Science.gov (United States)

    Sheen, Mee Rie; Lizotte, Patrick H; Toraya-Brown, Seiko; Fiering, Steven

    2014-01-01

    A variety of strategies, have been applied to cancer treatment and the most recent one to become prominent is immunotherapy. This interest has been fostered by the demonstration that the immune system does recognize and often eliminate small tumors but tumors that become clinical problems block antitumor immune responses with immunosuppression orchestrated by the tumor cells. Methods to reverse this tumor-mediated immunosuppression will improve cancer immunotherapy outcomes. The immunostimulatory potential of nanoparticles (NPs), holds promise for cancer treatment. Phagocytes of various types are an important component of both immunosuppression and immunostimulation and phagocytes actively take up NPs of various sorts, so NPs are a natural system to manipulate these key immune regulatory cells. NPs can be engineered with multiple useful therapeutic features, such as various payloads such as antigens and/or immunomodulatory agents including cytokines, ligands for immunostimulatory receptors or antagonists for immunosuppressive receptors. As more is learned about how tumors suppress antitumor immune responses the payload options expand further. Here we review multiple approaches of NP-based cancer therapies to modify the tumor microenvironment and stimulate innate and adaptive immune systems to obtain effective antitumor immune responses.

  6. Violet stimulated luminescence: geo- or thermochronometer?

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Guralnik, Benny; Porat, N.

    2015-01-01

    The method of quartz optically stimulated luminescence (OSL) dating is widely used, but generally limited to the past ~0.1 million years (Ma) due to early saturation of the desired signal. Violet stimulated luminescence (VSL) of quartz has previously been shown as a promising alternative...

  7. Electrocutaneous stimulation system for Braille reading.

    Science.gov (United States)

    Echenique, Ana Maria; Graffigna, Juan Pablo; Mut, Vicente

    2010-01-01

    This work is an assistive technology for people with visual disabilities and aims to facilitate access to written information in order to achieve better social inclusion and integration into work and educational activities. Two methods of electrical stimulation (by current and voltage) of the mechanoreceptors was tested to obtain tactile sensations on the fingertip. Current and voltage stimulation were tested in a Braille cell and line prototype, respectively. These prototypes are evaluated in 33 blind and visually impaired subjects. The result of experimentation with both methods showed that electrical stimulation causes sensations of touch defined in the fingertip. Better results in the Braille characters reading were obtained with current stimulation (85% accuracy). However this form of stimulation causes uncomfortable sensations. The latter feeling was minimized with the method of voltage stimulation, but with low efficiency (50% accuracy) in terms of identification of the characters. We concluded that electrical stimulation is a promising method for the development of a simple and unexpensive Braille reading system for blind people. We observed that voltage stimulation is preferred by the users. However, more experimental tests must be carry out in order to find the optimum values of the stimulus parameters and increase the accuracy the Braille characters reading.

  8. Oligofructose stimulates calcium absorption in adolescents

    NARCIS (Netherlands)

    Heuvel, E.G.H.M. van den; Muys, T.; Dokkum, W. van; Schaafsma, G.

    1999-01-01

    Background: In rats, nondigestible oligosaccharides stimulate calcium absorption. Recently, this effect was also found in human subjects. Objective: The objective of the study was to investigate whether consumption of 15 g oligofructose/d stimulates calcium absorption in male adolescents. Design: Tw

  9. Violet stimulated luminescence: geo- or thermochronometer?

    DEFF Research Database (Denmark)

    Ankjærgaard, Christina; Guralnik, Benny; Porat, N.;

    2015-01-01

    The method of quartz optically stimulated luminescence (OSL) dating is widely used, but generally limited to the past ~0.1 million years (Ma) due to early saturation of the desired signal. Violet stimulated luminescence (VSL) of quartz has previously been shown as a promising alternative...

  10. Effects of Vibrotactile Stimulation During Virtual Sandboarding

    DEFF Research Database (Denmark)

    Lind, Stine; Thomsen, Lui; Egebjerg, Mie

    2016-01-01

    This poster details a within-subjects study (n=17) investigating the effects of vibrotactile stimulation on illusory self-motion, presence and perceived realism during an interactive sandboarding simulation. Vibrotactile feedback was delivered using a low frequency audio transducer mounted undern...... of vibrotactile feedback. No significant differences were found between the two conditions involving vibrotactile stimulation....

  11. Vagus nerve stimulation in clinical practice.

    Science.gov (United States)

    Farmer, Adam D; Albu-Soda, Ahmed; Aziz, Qasim

    2016-11-02

    The diverse array of end organ innervations of the vagus nerve, coupled with increased basic science evidence, has led to vagus nerve stimulation becoming a management option in a number of clinical disorders. This review discusses methods of electrically stimulating the vagus nerve and its current and potential clinical uses.

  12. Passive auditory stimulation improves vision in hemianopia.

    Directory of Open Access Journals (Sweden)

    Jörg Lewald

    Full Text Available UNLABELLED: Techniques employed in rehabilitation of visual field disorders such as hemianopia are usually based on either visual or audio-visual stimulation and patients have to perform a training task. Here we present results from a completely different, novel approach that was based on passive unimodal auditory stimulation. Ten patients with either left or right-sided pure hemianopia (without neglect received one hour of unilateral passive auditory stimulation on either their anopic or their intact side by application of repetitive trains of sound pulses emitted simultaneously via two loudspeakers. Immediately before and after passive auditory stimulation as well as after a period of recovery, patients completed a simple visual task requiring detection of light flashes presented along the horizontal plane in total darkness. The results showed that one-time passive auditory stimulation on the side of the blind, but not of the intact, hemifield of patients with hemianopia induced an improvement in visual detections by almost 100% within 30 min after passive auditory stimulation. This enhancement in performance was reversible and was reduced to baseline 1.5 h later. A non-significant trend of a shift of the visual field border toward the blind hemifield was obtained after passive auditory stimulation. These results are compatible with the view that passive auditory stimulation elicited some activation of the residual visual pathways, which are known to be multisensory and may also be sensitive to unimodal auditory stimuli as were used here. TRIAL REGISTRATION: DRKS00003577.

  13. Deep Stimulation at Newberry Volcano EGS Demonstration

    Science.gov (United States)

    Grasso, K.; Cladouhos, T. T.; Petty, S.; Garrison, G. H.; Nordin, Y.; Uddenberg, M.; Swyer, M.

    2014-12-01

    The Newberry Volcano EGS Demonstration is a 5 year field project designed to demonstrate recent technological advances for engineered geothermal systems (EGS) development. Advances in reservoir stimulation, diverter, and monitoring are being tested in a hot (>300 C), dry well (NWG 55-29) drilled in 2008. These technologies could reduce the cost of electrical power generation. The project began in 2010 with two years of permitting, technical planning, and development of a project-specific Induced Seismicity Mitigation Plan (ISMP), and is funded in part by the Department of Energy. In 2012, the well was hydraulically stimulated with water at pressures below the principle stress for 7 weeks, resulting in hydroshearing. The depth of stimulation was successfully shifted by injection of two pills of Thermally-degradable Zonal Isolation Materials (TZIMs). Injectivity changes, thermal profiles and seismicity indicate that fracture permeability in well NWG 55-29 was enhanced during stimulation. This work successfully demonstrated the viability of large-volume (40,000 m3), low-pressure stimulation coupled with non-mechanical diverter technology, and microseismic monitoring for reservoir mapping. Further analysis and field testing in 2013 indicates further stimulation will be required in order to develop an economically viable reservoir, and is scheduled in 2014. The 2014 stimulation will use improved stimulation and monitoring equipment, better knowledge based on 2012 outcomes, and create a deep EGS reservoir in the hottest part of the wellbore.

  14. Modeling bipolar stimulation of cardiac tissue

    Science.gov (United States)

    Galappaththige, Suran K.; Gray, Richard A.; Roth, Bradley J.

    2017-09-01

    Unipolar stimulation of cardiac tissue is often used in the design of cardiac pacemakers because of the low current required to depolarize the surrounding tissue at rest. However, the advantages of unipolar over bipolar stimulation are not obvious at shorter coupling intervals when the tissue near the pacing electrode is relatively refractory. Therefore, this paper analyzes bipolar stimulation of cardiac tissue. The strength-interval relationship for bipolar stimulation is calculated using the bidomain model and a recently developed parsimonious ionic current model. The strength-interval curves obtained using different electrode separations and arrangements (electrodes placed parallel to the fibers versus perpendicular to the fibers) indicate that bipolar stimulation results in more complex activation patterns compared to unipolar stimulation. An unusually low threshold stimulus current is observed when the electrodes are close to each other (a separation of 1 mm) because of break excitation. Unlike for unipolar stimulation, anode make excitation is not present during bipolar stimulation, and an abrupt switch from anode break to cathode make excitation can cause dramatic changes in threshold with very small changes in the interval. These results could impact the design of implantable pacemakers and defibrillators.

  15. [MRI compatibility of deep brain stimulator].

    Science.gov (United States)

    Zhang, Yujing

    2013-07-01

    Deep brain stimulation (DBS) therapy develops rapidly in clinical application. The structures of deep brain stimulator and magnetic resonance imaging (MRI) equipment are introduced, the interactions are analyzed, and the two compatible problems of radio frequency (RF) heating and imaging artifact are summarized in this paper.

  16. Kinetics of infrared stimulated luminescence from feldspars

    DEFF Research Database (Denmark)

    Jain, Mayank; Sohbati, Reza; Guralnik, Benny;

    2015-01-01

    thermal and optical, of the infrared stimulated luminescence signal from feldspar. Based on the application of this model, it is concluded that different infra-red stimulated luminescence emissions (UV, blue, yellow and far-red) follow the same kinetics, and, therefore, involve participation of the same...

  17. Electronic stimulators for surface neural prosthesis

    Directory of Open Access Journals (Sweden)

    Broderick Barry J.

    2008-01-01

    Full Text Available This paper presents the technological advancements in neural prosthesis devices using Functional Electrical Stimulation (FES. FES refers to the restoration of motor functions lost due to spinal cord injury (SCI, stroke, head injury, or diseases such as Cerebral Palsy or Multiple Sclerosis by eliciting muscular contractions through the use of a neuromuscular electrical stimulator device. The field has developed considerably since its inception, with the miniaturisation of circuity, the development of programmable and adaptable stimulators and the enhancement of sensors used to trigger the application of stimulation to suit a variety of FES applications. This paper discusses general FES system design requirements in the context of existing commercial and research FES devices, focusing on surface stimulators for the upper and lower limbs. These devices have demonstrated feasible standing and stepping in a clinical setting with paraplegic patients, improvements in dropped foot syndrome with hemiplegic patients and aided in the restoration of grasping function in patients with upper limb motor dysfunction.

  18. Point Electric Stimulation and Children's Amblyopia

    Institute of Scientific and Technical Information of China (English)

    YAN Xing-ke; CHU Hui-ju; WANG Fu-chun; YANG Bo; GAO Yang; HAN Chou-ping

    2007-01-01

    To observe the therapeutic efficacy of electric stimulation on points for children's amblyopia.Method:Ninety children amblyopia cases with ametropia upon correction were randomized into three groups:point electric stimulation,comprehensive conventional therapy and integrative therapy of the above two.And then visual function changes of kids in the three groups were observed.Results:Among the above three therapies,the recovery rates of point electric stimulation,comprehensive conventional therapy and integrative therapy of the two were 83.9%,82.6%and 94.25 respectively,showing no significant difierence(P>0.05) among the three groups.Conclusion:Point electric stimulation has similar action with comprehensive conventional therapy in the treatment of children's amblyopia,and the combination of the two therapies has better effect,indicating point electric stimulation can speed up recovery of visual function of kids with amblyopia.

  19. Microscopic magnetic stimulation of neural tissue.

    Science.gov (United States)

    Bonmassar, Giorgio; Lee, Seung Woo; Freeman, Daniel K; Polasek, Miloslav; Fried, Shelley I; Gale, John T

    2012-06-26

    Electrical stimulation is currently used to treat a wide range of cardiovascular, sensory and neurological diseases. Despite its success, there are significant limitations to its application, including incompatibility with magnetic resonance imaging, limited control of electric fields and decreased performance associated with tissue inflammation. Magnetic stimulation overcomes these limitations but existing devices (that is, transcranial magnetic stimulation) are large, reducing their translation to chronic applications. In addition, existing devices are not effective for deeper, sub-cortical targets. Here we demonstrate that sub-millimeter coils can activate neuronal tissue. Interestingly, the results of both modelling and physiological experiments suggest that different spatial orientations of the coils relative to the neuronal tissue can be used to generate specific neural responses. These results raise the possibility that micro-magnetic stimulation coils, small enough to be implanted within the brain parenchyma, may prove to be an effective alternative to existing stimulation devices.

  20. Brain stimulation in posttraumatic stress disorder.

    Science.gov (United States)

    Novakovic, Vladan; Sher, Leo; Lapidus, Kyle A B; Mindes, Janet; A Golier, Julia; Yehuda, Rachel

    2011-01-01

    Posttraumatic stress disorder (PTSD) is a complex, heterogeneous disorder that develops following trauma and often includes perceptual, cognitive, affective, physiological, and psychological features. PTSD is characterized by hyperarousal, intrusive thoughts, exaggerated startle response, flashbacks, nightmares, sleep disturbances, emotional numbness, and persistent avoidance of trauma-associated stimuli. The efficacy of available treatments for PTSD may result in part from relief of associated depressive and anxiety-related symptoms in addition to treatment of core symptoms that derive from reexperiencing, numbing, and hyperarousal. Diverse, heterogeneous mechanisms of action and the ability to act broadly or very locally may enable brain stimulation devices to address PTSD core symptoms in more targeted ways. To achieve this goal, specific theoretical bases derived from novel, well-designed research protocols will be necessary. Brain stimulation devices include both long-used and new electrical and magnetic devices. Electroconvulsive therapy (ECT) and Cranial electrotherapy stimulation (CES) have both been in use for decades; transcranial magnetic stimulation (TMS), magnetic seizure therapy (MST), deep brain stimulation (DBS), transcranial Direct Current Stimulation (tDCS), and vagus nerve stimulation (VNS) have been developed recently, over approximately the past twenty years. The efficacy of brain stimulation has been demonstrated as a treatment for psychiatric and neurological disorders such as anxiety (CES), depression (ECT, CES, rTMS, VNS, DBS), obsessive-compulsive disorder (OCD) (DBS), essential tremor, dystonia (DBS), epilepsy (DBS, VNS), Parkinson Disease (DBS), pain (CES), and insomnia (CES). To date, limited data on brain stimulation for PTSD offer only modest guidance. ECT has shown some efficacy in reducing comorbid depression in PTSD patients but has not been demonstrated to improve most core PTSD symptoms. CES and VNS have shown some efficacy in

  1. Cranial electrotherapy stimulation and fibromyalgia.

    Science.gov (United States)

    Gilula, Marshall F

    2007-07-01

    Cranial electrotherapy stimulation (CES) is a well-documented neuroelectrical modality that has been proven effective in some good studies of fibromyalgia (FM) patients. CES is no panacea but, for some FM patients, the modality can be valuable. This article discusses aspects of both CES and FM and how they relate to the individual with the condition. FM frequently has many comorbidities such as anxiety, depression, insomnia and a great variety of different rheumatologic and neurological symptoms that often resemble multiple sclerosis, dysautonomias, chronic fatigue syndrome and others. However, despite long-standing criteria from the American College of Rheumatology for FM, some physicians believe there is probably no single homogeneous condition that can be labeled as FM. Whether it is a disease, a syndrome or something else, sufferers feel like they are living one disaster after another. Active self-involvement in care usually enhances the therapeutic results of various treatments and also improves the patient's sense of being in control of the condition. D-ribose supplementation may prove to significantly enhance energy, sleep, mental clarity, pain control and well-being in FM patients. A form of evoked potential biofeedback, the EPFX, is a powerful stress reduction technique which assesses the chief stressors and risk factors for illness that can impede the FM patient's built-in healing abilities. Future healthcare will likely expand the diagnostic criteria of FM and/or illuminate a group of related conditions and the ways in which the conditions relate to each other. Future medicine for FM and related conditions may increasingly involve multimodality treatment that features CES as one significant part of the therapeutic regimen. Future medicine may also include CES as an invaluable, cost-effective add-on to many facets of clinical pharmacology and medical therapeutics.

  2. Stimulating the Comfort of Textile Electrodes in Wearable Neuromuscular Electrical Stimulation

    Directory of Open Access Journals (Sweden)

    Hui Zhou

    2015-07-01

    Full Text Available Textile electrodes are becoming an attractive means in the facilitation of surface electrical stimulation. However, the stimulation comfort of textile electrodes and the mechanism behind stimulation discomfort is still unknown. In this study, a textile stimulation electrode was developed using conductive fabrics and then its impedance spectroscopy, stimulation thresholds, and stimulation comfort were quantitatively assessed and compared with those of a wet textile electrode and a hydrogel electrode on healthy subjects. The equivalent circuit models and the finite element models of different types of electrode were built based on the measured impedance data of the electrodes to reveal the possible mechanism of electrical stimulation pain. Our results showed that the wet textile electrode could achieve similar stimulation performance as the hydrogel electrode in motor threshold and stimulation comfort. However, the dry textile electrode was found to have very low pain threshold and induced obvious cutaneous painful sensations during stimulation, in comparison to the wet and hydrogel electrodes. Indeed, the finite element modeling results showed that the activation function along the z direction at the depth of dermis epidermis junction of the dry textile electrode was significantly larger than that of the wet and hydrogel electrodes, thus resulting in stronger activation of pain sensing fibers. Future work will be done to make textile electrodes have similar stimulation performance and comfort as hydrogel electrodes.

  3. Numerical dosimetry of transcranial magnetic stimulation coils

    Science.gov (United States)

    Crowther, Lawrence; Hadimani, Ravi; Jiles, David

    2014-03-01

    Transcranial magnetic stimulation (TMS) is a non-invasive neuromodulation technique capable of stimulating neurons by means of electromagnetic induction. TMS can be used to map brain function and shows promise for the diagnosis and treatment of neurological and psychiatric disorders. Calculation of fields induced in the brain are necessary to accurately identify stimulated neural tissue during TMS. This allows the development of novel TMS coil designs capable of stimulating deeper brain regions and increasing the localization of stimulation that can be achieved. We have performed numerical calculations of magnetic and electric field with high-resolution anatomically realistic human head models to find these stimulated brain regions for a variety of proposed TMS coil designs. The realistic head models contain heterogeneous tissue structures and electrical conductivities, yielding superior results to those obtained from the simplified homogeneous head models that are commonly employed. The attenuation of electric field as a function of depth in the brain and the localization of stimulating field have been methodically investigated. In addition to providing a quantitative comparison of different TMS coil designs the variation of induced field between subjects has been investigated. We also show the differences in induced fields between adult, adolescent and child head models to preemptively identify potential safety issues in the application of pediatric TMS.

  4. Transcranial magnetic stimulation intensities in cognitive paradigms.

    Directory of Open Access Journals (Sweden)

    Jakob A Kaminski

    Full Text Available BACKGROUND: Transcranial magnetic stimulation (TMS has become an important experimental tool for exploring the brain's functional anatomy. As TMS interferes with neural activity, the hypothetical function of the stimulated area can thus be tested. One unresolved methodological issue in TMS experiments is the question of how to adequately calibrate stimulation intensities. The motor threshold (MT is often taken as a reference for individually adapted stimulation intensities in TMS experiments, even if they do not involve the motor system. The aim of the present study was to evaluate whether it is reasonable to adjust stimulation intensities in each subject to the individual MT if prefrontal regions are stimulated prior to the performance of a cognitive paradigm. METHODS AND FINDINGS: Repetitive TMS (rTMS was applied prior to a working memory task, either at the 'fixed' intensity of 40% maximum stimulator output (MSO, or individually adapted at 90% of the subject's MT. Stimulation was applied to a target region in the left posterior middle frontal gyrus (pMFG, as indicated by a functional magnetic resonance imaging (fMRI localizer acquired beforehand, or to a control site (vertex. Results show that MT predicted the effect size after stimulating subjects with the fixed intensity (i.e., subjects with a low MT showed a greater behavioral effect. Nevertheless, the individual adaptation of intensities did not lead to stable effects. CONCLUSION: Therefore, we suggest assessing MT and account for it as a measure for general cortical TMS susceptibility, even if TMS is applied outside the motor domain.

  5. Remediación de suelos contaminados con mercurio utilizando guarumo (Cecropia peltata

    Directory of Open Access Journals (Sweden)

    Jhon Víctor Vidal Durango

    2010-01-01

    Full Text Available La contaminación de suelos por el mercurio resultante de la explotación aurífera puede ser remediada mediante la utilización de plantas que lo acumulan en sus tejidos, disminuyendo su impacto sobre los ecosistemas y la salud humana. En este trabajo se determinó la influencia del grado de contaminación, la aplicación de ácido cítrico y tiempo de crecimiento del guarumo, sobre la tasa de remoción de mercurio en suelo. Después de 4 meses de crecimiento, los porcentajes de remoción estuvieron entre 15.7% y 33.7% debido a la capacidad del guarumo para acumular grandes cantidades del metal sin presentar efectos tóxicos considerables, así como al alto contenido de mercurio biodisponible en los suelos contaminados, lo que conllevó también a que el ácido cítrico no tuviera una influencia significativa sobre la recuperación de Hg; por lo cual se concluyó, que el guarumo es una especie con capacidad fitorremediadora.

  6. In vitro phytochemical characteristics and antioxidant capacity of Aloe vera, Plukenetia volubilis, Caiophora carduifolia, Cecropia membranacea

    OpenAIRE

    Franco Quino, César; Unidad de Posgrado, Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos, Lima, Perú; Laboratorio de Fisiología y Farmacología, Facultad de Odontología, UNMSM, Lima, Perú; Muñoz Espinoza, Danny; Unidad de Posgrado, Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos, Lima, Perú; Facultad de Ciencias Químicas, Universidad de Guayaquil, Ecuador; Gómez Herreros, César; Unidad de Posgrado, Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos, Lima, Perú; Chau Miranda, Gina; Unidad de Posgrado, Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos, Lima, Perú; Cueva Piña, Liliana; Unidad de Posgrado, Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos, Lima, Perú; Guardia Ortiz, Eliza; Unidad de Posgrado, Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos, Lima, Perú; Saavedra Yucra, Santos; Unidad de Posgrado, Facultad de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos, Lima, Perú; Arroyo Acevedo, Jorge; Laboratorio de Farmacología Experimental, Facultad de Medicina Humana, UNMSM, Lima, Perú; Instituto de Investigaciones Clínicas, UNMSM, Lima, Perú; Herrera Calderón, Oscar; Facultad de Fisiología y Fisiopatología, Facultad de Farmacia y Bioquímica, Universidad Nacional San Luis Gonzaga, Ica, Perú

    2016-01-01

    Introduction. Antioxidants have shown chemopreventive potential in degenerative, inflammatory, autoimmune, oncology and respiratory distress associated pathologies. Objective. To assess the phytochemical and antioxidant properties in vitro by DPPH and ABTS method. Design. Observational analytical. Location. Laboratory of Experimental Pharmacology, Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru. Biological/Chemical Material. Aloe vera leaves, Plukenetia volubilis see...

  7. Stimulation Technologies for Deep Well Completions

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Wolhart

    2005-06-30

    The Department of Energy (DOE) is sponsoring the Deep Trek Program targeted at improving the economics of drilling and completing deep gas wells. Under the DOE program, Pinnacle Technologies conducted a study to evaluate the stimulation of deep wells. The objective of the project was to review U.S. deep well drilling and stimulation activity, review rock mechanics and fracture growth in deep, high-pressure/temperature wells and evaluate stimulation technology in several key deep plays. This report documents results from this project.

  8. Electrical Cerebral Stimulation Modifies Inhibitory Systems

    Science.gov (United States)

    Cuéllar-Herrera, M.; Rocha, L.

    2003-09-01

    Electrical stimulation of the nervous tissue has been proposed as a method to treat some neurological disorders, such as epilepsy. Epileptic seizures result from excessive, synchronous, abnormal firing patterns of neurons that are located predominantly in the cerebral cortex. Many people with epilepsy continue presenting seizures even though they are under regimens of antiepileptic medications. An alternative therapy for treatment resistant epilepsy is cerebral electrical stimulation. The present study is focused to review the effects of different types of electrical stimulation and specifically changes in amino acids.

  9. Elevated progesterone during ovarian stimulation for IVF

    DEFF Research Database (Denmark)

    Al-Azemi, M; Kyrou, D; Kolibianakis, E M

    2012-01-01

    of Medline and PubMed were searched to identify relevant publications. Good-quality evidence supports the negative impact on endometrial receptivity of elevated progesterone concentrations at the end of the follicular phase in ovarian stimulation. Future trials should document the cause and origin...... phase in ovarian stimulation. The databases of Medline and PubMed were searched to identify relevant publications. Good-quality evidence supports the negative impact on endometrial receptivity of elevated progesterone concentrations at the end of follicular phase in ovarian stimulation. Future trials...

  10. Free software for vision stimulation services

    Directory of Open Access Journals (Sweden)

    Priscila Batista Martins

    2012-10-01

    Full Text Available PURPOSE: To develop free software (SAEVI to improve the vision stimulation services. METHODS: The software of visual stimulation service (SAEVI was developed in microsoft Acess®, version 2003. Results: This database management system allows an efficient patients control and specific patient's appointments, such as: ophthalmological diagnostic and year of the appointment, and also other options, providing reports of each item. CONCLUSION: Professionals who work with visual stimulation or in related areas may be benefited from using the software to organize their work routines.

  11. Computational analysis of transcranial magnetic stimulation in the presence of deep brain stimulation probes

    Science.gov (United States)

    Syeda, F.; Holloway, K.; El-Gendy, A. A.; Hadimani, R. L.

    2017-05-01

    Transcranial Magnetic Stimulation is an emerging non-invasive treatment for depression, Parkinson's disease, and a variety of other neurological disorders. Many Parkinson's patients receive the treatment known as Deep Brain Stimulation, but often require additional therapy for speech and swallowing impairment. Transcranial Magnetic Stimulation has been explored as a possible treatment by stimulating the mouth motor area of the brain. We have calculated induced electric field, magnetic field, and temperature distributions in the brain using finite element analysis and anatomically realistic heterogeneous head models fitted with Deep Brain Stimulation leads. A Figure of 8 coil, current of 5000 A, and frequency of 2.5 kHz are used as simulation parameters. Results suggest that Deep Brain Stimulation leads cause surrounding tissues to experience slightly increased E-field (Δ Emax =30 V/m), but not exceeding the nominal values induced in brain tissue by Transcranial Magnetic Stimulation without leads (215 V/m). The maximum temperature in the brain tissues surrounding leads did not change significantly from the normal human body temperature of 37 °C. Therefore, we ascertain that Transcranial Magnetic Stimulation in the mouth motor area may stimulate brain tissue surrounding Deep Brain Stimulation leads, but will not cause tissue damage.

  12. Stimulation dependent induction of fear and depression in deep brain stimulation: a case report

    Directory of Open Access Journals (Sweden)

    Sabolek Michael

    2009-09-01

    Full Text Available Abstract Introduction Psychiatric side effects of deep brain stimulation are not uncommon. It is often limited to transient mood alterations. We report for the first time a case of acute stimulation-dependent fear during intraoperative test stimulation. Case presentation During test stimulation for electrode placement to the left subthalamic nucleus, a 58-year-old caucasian man with Parkinson's disease developed a severe reproducible feeling of fear together with elevated heart rate and sweating. Postoperatively, the patient developed a therapy refractory major depression in spite of excellent motor-control. Reprogramming the stimulator using a more rostral contact resulted in an abrupt and complete disappearance of the depressive syndrome. Conclusion Postoperative re-evaluation of the stimulation site of the patient inducing acute fear by analyzing his intraoperative microrecordings and Talairach coordinates revealed stimulation within his right substantia nigra. The contrast analysis of the postoperative stimulation site suggests induction of depression in the patient by stimulation of the caudal part of his subthalamic nucleus. Acute psychiatric side effects of deep brain stimulation are relatively rare but must not be overlooked while concentrating on the improvement of motor deficit.

  13. Temporal pattern of stimulation modulates reflex bladder activation by pudendal nerve stimulation.

    Science.gov (United States)

    McGee, Meredith J; Grill, Warren M

    2016-11-01

    Reflex bladder activation and inhibition by electrical stimulation of pudendal nerve (PN) afferents is a promising approach to restore control of bladder function in persons with lower urinary tract dysfunction caused by disease or injury. The objective of this work was to determine whether bladder activation evoked by pudendal afferent stimulation was dependent on the temporal pattern of stimulation, and whether specific temporal patterns of stimulation produced larger bladder contractions than constant frequency stimulation. The mean and maximum contraction pressures evoked by different temporal patterns of stimulation of the dorsal genital branch of the pudendal nerve were measured under isovolumetric conditions in α-chloralose anesthetized cats. A computational model of the spinal neural network mediating the pudendo-vesical reflex was used to understand the mechanisms of different bladder responses to patterned stimulation. The pattern of stimulation significantly affected the magnitude of evoked bladder contractions; several temporal patterns were as effective as regular stimulation, but no pattern evoked larger bladder contractions. Random patterns and patterns with pauses, burst-like activity, or high frequency components evoked significantly smaller bladder contractions, supporting the use of regular frequency stimulation in the development of neural prosthetic approaches for bladder control. These results reveal that the bladder response to pudendal afferent stimulation is dependent on the pattern, as well as the frequency, of stimulation. The computational model revealed that the effects of patterned pudendal afferent stimulation were determined by the dynamic properties of excitatory and inhibitory interneurons in the lumbosacral spinal cord. Neurourol. Urodynam. 35:882-887, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  14. Stimulation Technologies for Deep Well Completions

    Energy Technology Data Exchange (ETDEWEB)

    None

    2003-09-30

    The Department of Energy (DOE) is sponsoring the Deep Trek Program targeted at improving the economics of drilling and completing deep gas wells. Under the DOE program, Pinnacle Technologies is conducting a study to evaluate the stimulation of deep wells. The objective of the project is to assess U.S. deep well drilling & stimulation activity, review rock mechanics & fracture growth in deep, high pressure/temperature wells and evaluate stimulation technology in several key deep plays. An assessment of historical deep gas well drilling activity and forecast of future trends was completed during the first six months of the project; this segment of the project was covered in Technical Project Report No. 1. The second progress report covers the next six months of the project during which efforts were primarily split between summarizing rock mechanics and fracture growth in deep reservoirs and contacting operators about case studies of deep gas well stimulation.

  15. Growth hormone stimulation test - series (image)

    Science.gov (United States)

    The growth hormone (GH) is a protein hormone released from the anterior pituitary gland under the control of the hypothalamus. In children, GH has growth-promoting effects on the body. It stimulates the ...

  16. Stimulating Personal Development and Knowledge Sharing

    NARCIS (Netherlands)

    Koper, Rob; Stefanov, Krassen; Dicheva, Darina

    2009-01-01

    Koper, R., Stefanov, K., & Dicheva, D. (Eds.) (2009). Proceedings of the 5th International TENCompetence Open Workshop "Stimulating Personal Development and Knowledge Sharing". October, 30-31, 2008, Sofia, Bulgaria: TENCompetence Workshop.

  17. Stimulating Personal Development and Knowledge Sharing

    NARCIS (Netherlands)

    Koper, Rob; Stefanov, Krassen; Dicheva, Darina

    2009-01-01

    Koper, R., Stefanov, K., & Dicheva, D. (Eds.) (2009). Proceedings of the 5th International TENCompetence Open Workshop "Stimulating Personal Development and Knowledge Sharing". October, 30-31, 2008, Sofia, Bulgaria: TENCompetence Workshop.

  18. Effect of Stimulant Medication on Growth

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2005-08-01

    Full Text Available Twenty-nine studies of growth in height of children (22 and late adolescents (7 with attention deficit hyperactivity disorder (ADHD treated with stimulant medication were reviewed at the University of Sydney, Australia.

  19. Neural adaptations to electrical stimulation strength training

    NARCIS (Netherlands)

    Hortobagyi, Tibor; Maffiuletti, Nicola A.

    2011-01-01

    This review provides evidence for the hypothesis that electrostimulation strength training (EST) increases the force of a maximal voluntary contraction (MVC) through neural adaptations in healthy skeletal muscle. Although electrical stimulation and voluntary effort activate muscle differently, there

  20. Ethical issues in deep brain stimulation

    NARCIS (Netherlands)

    M.H.N. Schermer (Maartje)

    2011-01-01

    textabstractDeep brain stimulation (DBS) is currently used to treat neurological disorders like Parkinson's disease, essential tremor, and dystonia, and is explored as an experimental treatment for psychiatric disorders like major depression and obsessive compulsive disorder. This mini review

  1. [Functional electric stimulation (FES) in cerebral palsy].

    Science.gov (United States)

    Miyazaki, M H; Lourenção, M I; Ribeiro Sobrinho, J B; Battistella, L R

    1992-01-01

    Our study concerns a patient with cerebral palsy, submitted to conventional occupational therapy and functional electrical stimulation. The results as to manual ability, spasticity, sensibility and synkinesis were satisfactory.

  2. NQR Stimulation Technique for Explosives Detection System

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A method of customization stimulation signal based on direct digital frequency synthesis (DDS) for Nuclear Quadrapole Resonance Explosives Detection System is presented. DDS has many advantages, such as high frequency resolution, high convert speed,

  3. Transcranial alternating current stimulation (tACS

    Directory of Open Access Journals (Sweden)

    Andrea eAntal

    2013-06-01

    Full Text Available Transcranial alternating current stimulation (tACS seems likely to open a new era of the field of noninvasive electrical stimulation of the human brain by directly interfering with cortical rhythms. It is expected to synchronize (by one single resonance frequency or desynchronize (e.g. by the application of several frequencies cortical oscillations. If applied long enough it may cause neuroplastic effects. In the theta range it may improve cognition when applied in phase. Alpha rhythms could improve motor performance, whereas beta intrusion may deteriorate them. TACS with both alpha and beta frequencies has a high likelihood to induce retinal phosphenes. Gamma intrusion can possibly interfere with attention. Stimulation in the ripple range induces intensity dependent inhibition or excitation in the motor cortex most likely by entrainment of neuronal networks, whereas stimulation in the low kHz range induces excitation by neuronal membrane interference. TACS in the 200 kHz range may have a potential in oncology.

  4. Optogenetic stimulation of myelination (Conference Presentation)

    Science.gov (United States)

    Yang, In Hong; Lee, Hae Ung; Thakor, Nitish V.

    2016-03-01

    Myelination is governed by axon-glia interaction which is modulated by neural activity. Currently, the effects of subcellular activation of neurons which induce neural activity upon myelination are not well understood. To identify if subcellular neuronal stimulation can enhance myelination, we developed a novel system for focal stimulation of neural activity with optogenetic in a compartmentalized microfluidic platform. In our systems, stimulation for neurons in restricted subcellular parts, such as cell bodies and axons promoted oligodendrocyte differentiation and the myelination of axons the just as much as whole cell activation of neurons did. The number of premature O4 positive oligodendrocytes was reduced and the numbers of mature and myelin basic protein-positive oligodendrocytes was increased both by subcellular optogenetic stimulation.

  5. Research progress of diagnostic transcranial magnetic stimulation

    Directory of Open Access Journals (Sweden)

    Bei HUANG

    2017-07-01

    Full Text Available Transcranial magnetic stimulation (TMS is a non-invasive and painless neuroelectrophysiological examination technology. TMS-motor evoked potential (TMS-MEP is widely used to assess motor cortex excitability and conduction of descending corticobulbar tract and corticospinal tract. Recently, deeper understanding on principles of magnetic stimulation and diversification of stimulation coil and pattern has greatly expanded the application of TMS in clinical diagnosis. Moreover, MEP operation procedures are becoming more scientific and standardized. This paper reviews the progress of conventional diagnostic TMS pattern, several special stimulation patterns and the combined application of TMS, electroencephalograpy (EEG and fMRI. DOI: 10.3969/j.issn.1672-6731.2017.04.011

  6. Treatment Pulse Application for Magnetic Stimulation

    Directory of Open Access Journals (Sweden)

    Sun-Seob Choi

    2011-01-01

    Full Text Available Treatment and diagnosis can be made in difficult areas simply by changing the output pulse form of the magnetic stimulation device. However, there is a limitation in the range of treatments and diagnoses of a conventional sinusoidal stimulation treatment pulse because the intensity, width, and form of the pulse must be changed according to the lesion type. This paper reports a multidischarge method, where the stimulation coils were driven in sequence via multiple switching control. The limitation of the existing simple sinusoidal pulse form could be overcome by changing the intensity, width, and form of the pulse. In this study, a new sequential discharge method was proposed to freely alter the pulse width. The output characteristics of the stimulation treatment pulse were examined according to the trigger signal delay applied to the switch at each stage by applying a range of superposition pulses to the magnetic simulation device, which is widely used in industry and medicine.

  7. Rewiring neural interactions by micro-stimulation

    Directory of Open Access Journals (Sweden)

    James M Rebesco

    2010-08-01

    Full Text Available Plasticity is a crucial component of normal brain function and a critical mechanism for recovery from injury. In vitro, associative pairing of presynaptic spiking and stimulus-induced postsynaptic depolarization causes changes in the synaptic efficacy of the presynaptic neuron, when activated by extrinsic stimulation. In vivo, such paradigms can alter the responses of whole groups of neurons to stimulation. Here, we used in vivo spike-triggered stimulation to drive plastic changes in rat forelimb sensorimotor cortex, which we monitored using a statistical measure of functional connectivity inferred from the spiking statistics of the neurons during normal, spontaneous behavior. These induced plastic changes in inferred functional connectivity depended on the latency between trigger spike and stimulation, and appear to reflect a robust reorganization of the network. Such targeted connectivity changes might provide a tool for rerouting the flow of information through a network, with implications for both rehabilitation and brain-machine interface applications.

  8. Medicinal Marijuana: A Legitimate Appetite Stimulant?

    OpenAIRE

    Aquino, Glen

    2005-01-01

    Medicinal marijuana has been at the center of controversy for the treatment of cancer cachexia and AIDS related weight loss. Dronabinol, the oral form of marijuana, was approved for appetite stimulation, but its variability in absorption has led researchers to believe that smoked marijuana may be more effective. The discovery of endocannabinoids and their receptors has drawn attention from the research community, and as a result, marijuana’s role in appetite stimulation is clearer. Marijua...

  9. Transcranial laser stimulation improves human cerebral oxygenation

    OpenAIRE

    2016-01-01

    Background and Objective Transcranial laser stimulation of the brain with near‐infrared light is a novel form of non‐invasive photobiomodulation or low‐level laser therapy (LLLT) that has shown therapeutic potential in a variety of neurological and psychological conditions. Understanding of its neurophysiological effects is essential for mechanistic study and treatment evaluation. This study investigated how transcranial laser stimulation influences cerebral hemodynamics and oxygenation in th...

  10. Tongue Liminary Threshold Identification to Electrotactile Stimulation

    CERN Document Server

    Robineau, Fabien; Orliaguet, Jean-Pierre; Payan, Yohan

    2007-01-01

    Many applications use electrostimulation of the human skin to provide tactile sensation. The effect of electrotactile stimulations were studied on a 6x6 matrix of tactile electrodes placed on the anterior part of the tongue. The liminary threshold with continuous or discontinuous waveform and patterns with 2 or 4 electrodes was investigated. The result suggest that for energy saving and to improve the yield, it would probably be better to use discontinuous stimulation with two electrode patterns.

  11. Transcranial magnetic stimulation and the human brain

    Science.gov (United States)

    Hallett, Mark

    2000-07-01

    Transcranial magnetic stimulation (TMS) is rapidly developing as a powerful, non-invasive tool for studying the human brain. A pulsed magnetic field creates current flow in the brain and can temporarily excite or inhibit specific areas. TMS of motor cortex can produce a muscle twitch or block movement; TMS of occipital cortex can produce visual phosphenes or scotomas. TMS can also alter the functioning of the brain beyond the time of stimulation, offering potential for therapy.

  12. VAGUS NERVE STIMULATION REGULATES HEMOSTASIS IN SWINE

    OpenAIRE

    Czura, Christopher J.; Schultz, Arthur; Kaipel, Martin; Khadem, Anna; Huston, Jared M.; Pavlov, Valentin A; Redl, Heinz; Tracey, Kevin J.

    2010-01-01

    The central nervous system regulates peripheral immune responses via the vagus nerve, the primary neural component of the cholinergic anti-inflammatory pathway. Electrical stimulation of the vagus nerve suppresses pro-inflammatory cytokine release in response to endotoxin, I/R injury, and hypovolemic shock and protects against lethal hypotension. To determine the effect of vagus nerve stimulation on coagulation pathways, anesthetized pigs were subjected to partial ear resection before and aft...

  13. Motor Cortex Stimulation in Parkinson's Disease

    OpenAIRE

    Marisa De Rose; Giusy Guzzi; Domenico Bosco; Mary Romano; Serena Marianna Lavano; Massimiliano Plastino; Giorgio Volpentesta; Rosa Marotta; Angelo Lavano

    2012-01-01

    Motor Cortex Stimulation (MCS) is less efficacious than Deep Brain Stimulation (DBS) in Parkinson's disease. However, it might be proposed to patients excluded from DBS or unresponsive to DBS. Ten patients with advanced PD underwent unilateral MCS contralaterally to the worst clinical side. A plate electrode was positioned over the motor cortex in the epidural space through single burr hole after identification of the area with neuronavigation and neurophysiological tests. Clinical assessment...

  14. Deep brain stimulation for cluster headache

    DEFF Research Database (Denmark)

    Grover, Patrick J; Pereira, Erlick A C; Green, Alexander L

    2009-01-01

    Cluster headache is a severely debilitating disorder that can remain unrelieved by current pharmacotherapy. Alongside ablative neurosurgical procedures, neuromodulatory treatments of deep brain stimulation (DBS) and occipital nerve simulation have emerged in the last few years as effective...... circumstances to intervene. Here we review current data on neurosurgical interventions for chronic cluster headache focusing upon DBS and occipital nerve stimulation, and discuss the indications for and putative mechanisms of DBS including translational insights from functional neuroimaging, diffusion weighted...

  15. Brain stimulation for treatment of refractory epilepsy

    Institute of Scientific and Technical Information of China (English)

    GE Yan; HU Wei; LIU Chong; ZHANG Jian-guo; MENG Fan-gang

    2013-01-01

    Objective We review the targets of the deep brain and the responsive neurostimulation system (RNS) to identify the best optimal stimulation parameters and the best mode of stimulation,whether cyclical,continuous,or smarter.Data sources This review is based on data obtained from published articles from 1950 to 2013.To perform the PubMed literature search,the following keywords were input:deep brain stimulation (DBS),RNS,and refractory epilepsy.Study selection Articles containing information related to brain stimulation or RNS for the treatment of refractory epilepsy were selected.Results The currently available treatment options for those patients who resist multiple antiepileptic medications and surgical procedures include electric stimulation,both direct and indirect,of brain nuclei thought to be involved in epileptogenesis.The number of potential targets has increased over the years to include the anterior nucleus of the thalamus,the centromedian nucleus of the thalamus,the hippocampus,the subthalamic nucleus,the caudate nucleus,and the cerebellum,among others.The results of a randomized controlled trial and the RNS trial were published to reveal the effectiveness.Conclusions Although statistically significant reductions in seizures have been observed using several different stimulation techniques,including vagus nerve stimulation,DBS,and RNS,these effects are currently only palliative and do not approach the efficacy comparable with that seen in resection in appropriately selected patients.More research is needed to determine optimal stimulation targets and techniques as well as to determine which epilepsy patients will benefit most from this technology.

  16. Effect of neurovestibular stimulation on autonomic regulation

    Science.gov (United States)

    Costa, F.; Lavin, P.; Robertson, D.; Biaggioni, I.

    1995-01-01

    Conditions associated with nausea and vomiting, such as motion sickness or side effects of medications, are commonly associated with a clinical picture consistent with parasympathetic activation and sympathetic withdrawal. It can be postulated, therefore, that vestibular stimulation contributes to sympathetic withdrawal. To test this hypothesis five normal volunteers, 24-33 years old, were studied during caloric vestibular stimulation while monitoring muscle sympathetic nerve activity directly through a needle electrode placed in a peroneal nerve. The ear was irrigated with water at a flow rate of 450 ml/min and 37 degrees C. The water temperature was sequentially lowered by 7 degree C intervals until intolerable side effects developed or a temperature of 16 degrees C was reached. Nystagmus was induced in all subjects, but heart rate, blood pressure, muscle sympathetic nerve activity and plasma norepinephrine levels did not change significantly during or after caloric stimulation, even when the subjects felt dizzy and nauseated. No evidence of sympathetic withdrawal was observed in any subject either by muscle sympathetic nerve activity or plasma norepinephrine measurements. In conclusion, we have found that selective vestibular stimulation is not accompanied by significant changes in the sympathetic nervous system function. In particular, no sympathetic withdrawal was observed. It could be argued that lack of sympathetic stimulation is an inadequate response to the symptoms associated with caloric stimulation.

  17. Effect of neurovestibular stimulation on autonomic regulation

    Science.gov (United States)

    Costa, F.; Lavin, P.; Robertson, D.; Biaggioni, I.

    1995-01-01

    Conditions associated with nausea and vomiting, such as motion sickness or side effects of medications, are commonly associated with a clinical picture consistent with parasympathetic activation and sympathetic withdrawal. It can be postulated, therefore, that vestibular stimulation contributes to sympathetic withdrawal. To test this hypothesis five normal volunteers, 24-33 years old, were studied during caloric vestibular stimulation while monitoring muscle sympathetic nerve activity directly through a needle electrode placed in a peroneal nerve. The ear was irrigated with water at a flow rate of 450 ml/min and 37 degrees C. The water temperature was sequentially lowered by 7 degree C intervals until intolerable side effects developed or a temperature of 16 degrees C was reached. Nystagmus was induced in all subjects, but heart rate, blood pressure, muscle sympathetic nerve activity and plasma norepinephrine levels did not change significantly during or after caloric stimulation, even when the subjects felt dizzy and nauseated. No evidence of sympathetic withdrawal was observed in any subject either by muscle sympathetic nerve activity or plasma norepinephrine measurements. In conclusion, we have found that selective vestibular stimulation is not accompanied by significant changes in the sympathetic nervous system function. In particular, no sympathetic withdrawal was observed. It could be argued that lack of sympathetic stimulation is an inadequate response to the symptoms associated with caloric stimulation.

  18. A microprocessor-based multichannel subsensory stochastic resonance electrical stimulator.

    Science.gov (United States)

    Chang, Gwo-Ching

    2013-01-01

    Stochastic resonance electrical stimulation is a novel intervention which provides potential benefits for improving postural control ability in the elderly, those with diabetic neuropathy, and stroke patients. In this paper, a microprocessor-based subsensory white noise electrical stimulator for the applications of stochastic resonance stimulation is developed. The proposed stimulator provides four independent programmable stimulation channels with constant-current output, possesses linear voltage-to-current relationship, and has two types of stimulation modes, pulse amplitude and width modulation.

  19. Differential stimulation of the retina with subretinally injected exogenous neurotransmitter: A biomimetic alternative to electrical stimulation

    Science.gov (United States)

    Rountree, Corey M.; Inayat, Samsoon; Troy, John B.; Saggere, Laxman

    2016-12-01

    Subretinal stimulation of the retina with neurotransmitters, the normal means of conveying visual information, is a potentially better alternative to electrical stimulation widely used in current retinal prostheses for treating blindness from photoreceptor degenerative diseases. Yet, no subretinal electrical or chemical stimulation study has stimulated the OFF and ON pathways differentially through inner retinal activation. Here, we demonstrate the feasibility of differentially stimulating retinal ganglion cells (RGCs) through the inner nuclear layer of the retina with glutamate, a primary neurotransmitter chemical, in a biomimetic way. We show that controlled pulsatile delivery of glutamate into the subsurface of explanted wild-type rat retinas elicits highly localized simultaneous inhibitory and excitatory spike rate responses in OFF and ON RGCs. We also present the spatiotemporal characteristics of RGC responses to subretinally injected glutamate and the therapeutic stimulation parameters. Our findings could pave the way for future development of a neurotransmitter-based subretinal prosthesis offering more naturalistic vision and better visual acuity than electrical prostheses.

  20. Vagus nerve stimulation for partial seizures.

    Science.gov (United States)

    Panebianco, Mariangela; Rigby, Alexandra; Weston, Jennifer; Marson, Anthony G

    2015-04-03

    Vagus nerve stimulation (VNS) is a neuromodulatory treatment that is used as an adjunctive therapy for treating people with medically refractory epilepsy. VNS consists of chronic intermittent electrical stimulation of the vagus nerve, delivered by a programmable pulse generator. The majority of people given a diagnosis of epilepsy have a good prognosis, and their seizures will be controlled by treatment with a single antiepileptic drug (AED), but up to 20%-30% of patients will develop drug-resistant epilepsy, often requiring treatment with combinations of AEDs. The aim of this systematic review was to overview the current evidence for the efficacy and tolerability of vagus nerve stimulation when used as an adjunctive treatment for people with drug-resistant partial epilepsy. This is an updated version of a Cochrane review published in Issue 7, 2010. To determine:(1) The effects on seizures of VNS compared to controls e.g. high-level stimulation compared to low-level stimulation (presumed sub-therapeutic dose); and(2) The adverse effect profile of VNS compared to controls e.g. high-level stimulation compared to low-level stimulation. We searched the Cochrane Epilepsy Group's Specialised Register (23 February 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 23 February 2015), MEDLINE (1946 to 23 February 2015), SCOPUS (1823 to 23 February 2015), ClinicalTrials.gov (23 February 2015) and ICTRP (23 February 2015). No language restrictions were imposed. The following study designs were eligible for inclusion: randomised, double-blind, parallel or crossover studies, controlled trials of VNS as add-on treatment comparing high and low stimulation paradigms (including three different stimulation paradigms - duty cycle: rapid, mid and slow) and VNS stimulation versus no stimulation or a different intervention. Eligible participants were adults or children with drug-resistant partial seizures not eligible for surgery or who failed

  1. The Codacs™ direct acoustic cochlear implant actuator: exploring alternative stimulation sites and their stimulation efficiency.

    Directory of Open Access Journals (Sweden)

    Martin Grossöhmichen

    Full Text Available This work assesses the efficiency of the Codacs system actuator (Cochlear Ltd., Sydney Australia in different inner ear stimulation modalities. Originally the actuator was intended for direct perilymph stimulation after stapedotomy using a piston prosthesis. A possible alternative application is the stimulation of middle ear structures or the round window (RW. Here the perilymph stimulation with a K-piston through a stapes footplate (SFP fenestration (N = 10 as well as stimulation of the stapes head (SH with a Bell prosthesis (N = 9, SFP stimulation with an Omega/Aerial prosthesis (N = 8 and reverse RW stimulation (N = 10 were performed in cadaveric human temporal bones (TBs. Codacs actuator output is expressed as equivalent sound pressure level (eq. SPL using RW and SFP displacement responses, measured by Laser Doppler velocimetry as reference. The axial actuator coupling force in stimulation of stapes and RW was adjusted to ~5 mN. The Bell prosthesis and Omega/Aerial prosthesis stimulation generated similar mean eq. SPLs (Bell: 127.5-141.8 eq. dB SPL; Omega/Aerial: 123.6-143.9 eq. dB SPL, being significantly more efficient than K-piston perilymph stimulation (108.6-131.6 eq. dB SPL and RW stimulation (108.3-128.2 eq. dB SPL. Our results demonstrate that SH, SFP and RW are adequate alternative stimulation sites for the Codacs actuator using coupling prostheses and an axial coupling force of ~5 mN. Based on the eq. SPLs, all investigated methods were adequate for in vivo hearing aid applications, provided that experimental conditions including constant coupling force will be implemented.

  2. Neuroethics of deep brain stimulation for mental disorders: brain stimulation reward in humans.

    Science.gov (United States)

    Oshima, Hideki; Katayama, Yoichi

    2010-01-01

    The theoretical basis of some deep brain stimulation (DBS) trials undertaken in the early years was the phenomenon of "brain stimulation reward (BSR)," which was first identified in rats. The animals appeared to be rewarded by pleasure caused by the stimulation of certain brain regions (reward system), such as the septal area. "Self-stimulation" experiments, in which rats were allowed to stimulate their own brain by pressing a freely accessible lever, they quickly learned lever pressing and sometimes continued to stimulate until they exhausted themselves. BSR was also observed with DBS of the septal area in humans. DBS trials in later years were undertaken on other theoretical bases, but unexpected BSR was sometimes induced by stimulation of some areas, such as the locus coeruleus complex. When BSR was induced, the subjects experienced feelings that were described as "cheerful," "alert," "good," "well-being," "comfort," "relaxation," "joy," or "satisfaction." Since the DBS procedure is equivalent to a "self-stimulation" experiment, they could become "addicted to the stimulation itself" or "compulsive about the stimulation," and stimulate themselves "for the entire day," "at maximum amplitude" and, in some instances, "into convulsions." DBS of the reward system has recently been applied to alleviate anhedonia in patients with refractory major depression. Although this approach appears promising, there remains a difficult problem: who can adjust their feelings and reward-oriented behavior within the normal range? With a self-stimulation procedure, the BSR may become uncontrollable. To develop DBS to the level of a standard therapy for mental disorders, we need to discuss "Who has the right to control the mental condition?" and "Who makes decisions" on "How much control is appropriate?" in daily life.

  3. The Codacs™ direct acoustic cochlear implant actuator: exploring alternative stimulation sites and their stimulation efficiency.

    Science.gov (United States)

    Grossöhmichen, Martin; Salcher, Rolf; Kreipe, Hans-Heinrich; Lenarz, Thomas; Maier, Hannes

    2015-01-01

    This work assesses the efficiency of the Codacs system actuator (Cochlear Ltd., Sydney Australia) in different inner ear stimulation modalities. Originally the actuator was intended for direct perilymph stimulation after stapedotomy using a piston prosthesis. A possible alternative application is the stimulation of middle ear structures or the round window (RW). Here the perilymph stimulation with a K-piston through a stapes footplate (SFP) fenestration (N = 10) as well as stimulation of the stapes head (SH) with a Bell prosthesis (N = 9), SFP stimulation with an Omega/Aerial prosthesis (N = 8) and reverse RW stimulation (N = 10) were performed in cadaveric human temporal bones (TBs). Codacs actuator output is expressed as equivalent sound pressure level (eq. SPL) using RW and SFP displacement responses, measured by Laser Doppler velocimetry as reference. The axial actuator coupling force in stimulation of stapes and RW was adjusted to ~5 mN. The Bell prosthesis and Omega/Aerial prosthesis stimulation generated similar mean eq. SPLs (Bell: 127.5-141.8 eq. dB SPL; Omega/Aerial: 123.6-143.9 eq. dB SPL), being significantly more efficient than K-piston perilymph stimulation (108.6-131.6 eq. dB SPL) and RW stimulation (108.3-128.2 eq. dB SPL). Our results demonstrate that SH, SFP and RW are adequate alternative stimulation sites for the Codacs actuator using coupling prostheses and an axial coupling force of ~5 mN. Based on the eq. SPLs, all investigated methods were adequate for in vivo hearing aid applications, provided that experimental conditions including constant coupling force will be implemented.

  4. Brain stimulation in posttraumatic stress disorder

    Directory of Open Access Journals (Sweden)

    Vladan Novakovic

    2011-10-01

    Full Text Available Posttraumatic stress disorder (PTSD is a complex, heterogeneous disorder that develops following trauma and often includes perceptual, cognitive, affective, physiological, and psychological features. PTSD is characterized by hyperarousal, intrusive thoughts, exaggerated startle response, flashbacks, nightmares, sleep disturbances, emotional numbness, and persistent avoidance of trauma-associated stimuli. The efficacy of available treatments for PTSD may result in part from relief of associated depressive and anxiety-related symptoms in addition to treatment of core symptoms that derive from reexperiencing, numbing, and hyperarousal. Diverse, heterogeneous mechanisms of action and the ability to act broadly or very locally may enable brain stimulation devices to address PTSD core symptoms in more targeted ways. To achieve this goal, specific theoretical bases derived from novel, well-designed research protocols will be necessary. Brain stimulation devices include both long-used and new electrical and magnetic devices. Electroconvulsive therapy (ECT and Cranial electrotherapy stimulation (CES have both been in use for decades; transcranial magnetic stimulation (TMS, magnetic seizure therapy (MST, deep brain stimulation (DBS, transcranial Direct Current Stimulation (tDCS, and vagus nerve stimulation (VNS have been developed recently, over approximately the past twenty years. The efficacy of brain stimulation has been demonstrated as a treatment for psychiatric and neurological disorders such as anxiety (CES, depression (ECT, CES, rTMS, VNS, DBS, obsessive-compulsive disorder (OCD (DBS, essential tremor, dystonia (DBS, epilepsy (DBS, VNS, Parkinson Disease (DBS, pain (CES, and insomnia (CES. To date, limited data on brain stimulation for PTSD offer only modest guidance. ECT has shown some efficacy in reducing comorbid depression in PTSD patients but has not been demonstrated to improve most core PTSD symptoms. CES and VNS have shown some efficacy in

  5. Stimulating at the right time: phase-specific deep brain stimulation

    Science.gov (United States)

    Pedrosa, David; Little, Simon; Pogosyan, Alek; Cheeran, Binith; Aziz, Tipu; Green, Alexander; Fitzgerald, James; Foltynie, Thomas; Limousin, Patricia; Zrinzo, Ludvic; Hariz, Marwan; Friston, Karl J.; Denison, Timothy; Brown, Peter

    2017-01-01

    See Moll and Engel (doi:10.1093/aww308) for a scientific commentary on this article. Brain regions dynamically engage and disengage with one another to execute everyday actions from movement to decision making. Pathologies such as Parkinson’s disease and tremor emerge when brain regions controlling movement cannot readily decouple, compromising motor function. Here, we propose a novel stimulation strategy that selectively regulates neural synchrony through phase-specific stimulation. We demonstrate for the first time the therapeutic potential of such a stimulation strategy for the treatment of patients with pathological tremor. Symptom suppression is achieved by delivering stimulation to the ventrolateral thalamus, timed according to the patient’s tremor rhythm. Sustained locking of deep brain stimulation to a particular phase of tremor afforded clinically significant tremor relief (up to 87% tremor suppression) in selected patients with essential tremor despite delivering less than half the energy of conventional high frequency stimulation. Phase-specific stimulation efficacy depended on the resonant characteristics of the underlying tremor network. Selective regulation of neural synchrony through phase-locked stimulation has the potential to both increase the efficiency of therapy and to minimize stimulation-induced side effects. PMID:28007997

  6. Mechanism of adrenergic stimulation of hepatic ketogenesis.

    Science.gov (United States)

    Kosugi, K; Harano, Y; Nakano, T; Suzuki, M; Kashiwagi, A; Shigeta, Y

    1983-11-01

    The effects of alpha- and beta-adrenergic stimulation on ketogenesis were examined in freshly isolated rat hepatocytes in order to determine which alpha- or beta-adrenergic stimulation is involved in the enhancement of ketogenesis. In the presence of 0.3 mmol/L (U-14C)-palmitate, epinephrine, norepinephrine, and phenylephrine at 500 ng/mL increased ketogenesis by 25% (16.0 +/- 0.17 v 12.8 +/- 0.13 nmol/mg protein per hour), 20% (15.3 +/- 0.28) and 20% (15.4 +/- 0.36), respectively. However, isoproterenol even at 1 microgram/mL did not stimulate ketogenesis. Phentolamine (5 micrograms/mL) almost completely abolished the effect of epinephrine on ketogenesis (13.7 +/- 0.30 v 16.0 +/- 0.17) but propranolol did not inhibit the stimulation by epinephrine (15.6 +/- 0.38 v 16.0 +/- 0.17). Trifluoperazine (10 mumol/L), presumably an inhibitor of calcium-dependent protein kinase, abolished the effect of epinephrine (13.6 +/- 0.22 v 16.0 +/- 0.17). These results indicate that catecholamines increase ketogenesis predominantly through the alpha-adrenergic system independent of cyclic AMP, and calcium-dependent protein kinase is thought to be involved in the activation of ketogenesis. On the other hand, glucagon stimulated ketogenesis with an increase of cyclic AMP, which was not inhibited by alpha- and beta-adrenergic antagonists. Alpha-adrenergic stimulation increased hepatic glycogenolysis much more at much lower concentrations when compared with ketogenesis. Stimulation of ketogenesis by catecholamines seemed to be less sensitive and responsive compared with hepatic glycogenolysis.

  7. In vitro magnetic stimulation: a simple stimulation device to deliver defined low intensity electromagnetic fields

    Directory of Open Access Journals (Sweden)

    Stephanie Grehl

    2016-11-01

    Full Text Available Non-invasive electromagnetic field brain stimulation (NIBS appears to benefit human neurological and psychiatric conditions, although the optimal stimulation parameters and underlying mechanisms remain unclear. Although in vitro studies have begun to elucidate cellular mechanisms, stimulation is delivered by a range of coils (from commercially available human stimulation coils to laboratory-built circuits so that the electromagnetic fields induced within the tissue to produce the reported effects are ill-defined.Here we develop a simple in vitro stimulation device with plug-and-play features that allow delivery of a range of stimulation parameters. We chose to test low intensity repetitive magnetic stimulation (LI-rMS delivered at 3 frequencies to hindbrain explant cultures containing the olivocerebellar pathway. We used computational modelling to define the parameters of a stimulation circuit and coil that deliver a unidirectional homogeneous magnetic field of known intensity and direction, and therefore a predictable electric field, to the target. We built the coil to be compatible with culture requirements: stimulation within an incubator; a flat surface allowing consistent position and magnetic field direction; location outside the culture plate to maintain sterility and no heating or vibration. Measurements at the explant confirmed the induced magnetic field was homogenous and matched the simulation results. To validate our system we investigated biological effects following LI-rMS at 1 Hz, 10 Hz and biomimetic high frequency (BHFS, which we have previously shown induces neural circuit reorganisation. We found that gene expression was modified by LI-rMS in a frequency-related manner. Four hours after a single 10-minute stimulation session, the number of c-fos positive cells increased, indicating that our stimulation activated the tissue. Also, after 14 days of LI-rMS, the expression of genes normally present in the tissue was differentially

  8. In vitro Magnetic Stimulation: A Simple Stimulation Device to Deliver Defined Low Intensity Electromagnetic Fields

    Science.gov (United States)

    Grehl, Stephanie; Martina, David; Goyenvalle, Catherine; Deng, Zhi-De; Rodger, Jennifer; Sherrard, Rachel M.

    2016-01-01

    Non-invasive brain stimulation (NIBS) by electromagnetic fields appears to benefit human neurological and psychiatric conditions, although the optimal stimulation parameters and underlying mechanisms remain unclear. Although, in vitro studies have begun to elucidate cellular mechanisms, stimulation is delivered by a range of coils (from commercially available human stimulation coils to laboratory-built circuits) so that the electromagnetic fields induced within the tissue to produce the reported effects are ill-defined. Here, we develop a simple in vitro stimulation device with plug-and-play features that allow delivery of a range of stimulation parameters. We chose to test low intensity repetitive magnetic stimulation (LI-rMS) delivered at three frequencies to hindbrain explant cultures containing the olivocerebellar pathway. We used computational modeling to define the parameters of a stimulation circuit and coil that deliver a unidirectional homogeneous magnetic field of known intensity and direction, and therefore a predictable electric field, to the target. We built the coil to be compatible with culture requirements: stimulation within an incubator; a flat surface allowing consistent position and magnetic field direction; location outside the culture plate to maintain sterility and no heating or vibration. Measurements at the explant confirmed the induced magnetic field was homogenous and matched the simulation results. To validate our system we investigated biological effects following LI-rMS at 1 Hz, 10 Hz and biomimetic high frequency, which we have previously shown induces neural circuit reorganization. We found that gene expression was modified by LI-rMS in a frequency-related manner. Four hours after a single 10-min stimulation session, the number of c-fos positive cells increased, indicating that our stimulation activated the tissue. Also, after 14 days of LI-rMS, the expression of genes normally present in the tissue was differentially modified

  9. Technological Advances in Deep Brain Stimulation.

    Science.gov (United States)

    Ughratdar, Ismail; Samuel, Michael; Ashkan, Keyoumars

    2015-01-01

    Functional and stereotactic neurosurgery has always been regarded as a subspecialty based on and driven by technological advances. However until recently, the fundamentals of deep brain stimulation (DBS) hardware and software design had largely remained stagnant since its inception almost three decades ago. Recent improved understanding of disease processes in movement disorders as well clinician and patient demands has resulted in new avenues of development for DBS technology. This review describes new advances both related to hardware and software for neuromodulation. New electrode designs with segmented contacts now enable sophisticated shaping and sculpting of the field of stimulation, potentially allowing multi-target stimulation and avoidance of side effects. To avoid lengthy programming sessions utilising multiple lead contacts, new user-friendly software allows for computational modelling and individualised directed programming. Therapy delivery is being improved with the next generation of smaller profile, longer-lasting, re-chargeable implantable pulse generators (IPGs). These include IPGs capable of delivering constant current stimulation or personalised closed-loop adaptive stimulation. Post-implantation Magnetic Resonance Imaging (MRI) has long been an issue which has been partially overcome with 'MRI conditional devices' and has enabled verification of DBS lead location. Surgical technique is considering a shift from frame-based to frameless stereotaxy or greater role for robot assisted implantation. The challenge for these contemporary techniques however, will be in demonstrating equivalent safety and accuracy to conventional methods. We also discuss potential future direction utilising wireless technology allowing for miniaturisation of hardware.

  10. Transcranial magnetic stimulation of the cerebellum.

    Science.gov (United States)

    Minks, Eduard; Kopickova, Marie; Marecek, Radek; Streitova, Hana; Bares, Martin

    2010-06-01

    The cerebellum is a very complex structure with many motor/non-motor functions and direct and indirect connections with almost the entire central nervous system. Transcranial magnetic stimulation (TMS) is a non-invasive electrophysiological method for studying, diagnosing, and treating disorders of the nervous system. The aim of the present review is to summarise the research and potential clinical uses of cerebellar TMS. PubMed literature search using the key words "cerebellum TMS". TMS of the cerebellum is used in two types of protocols. The first type involves the separate stimulation of the cerebellum while tracking its clinical or electrophysiological influence on motor and non-motor functions. The second involves stimulation of the cerebellum as a conditioning stimulus before stimulating the motor cortex, to monitor the electrophysiological impact of cerebellar stimulation on the motor cortex. Most studies are performed on small groups of healthy volunteers; isolated studies are performed on patients with neurological disorders (spinocerebellar ataxia, migraine, dystonia, Miller Fisher syndrome). It has been shown that cerebellar TMS is able to influence motor systems, memory, and perception of time, and there is evidence of its electrophysiological effects in the frontal cortex. Published studies suggest that cerebellar TMS is currently only important in research. There is not yet any clear or reliable evidence of the therapeutic effects of cerebellar TMS. However, its use as a treatment method can be anticipated.

  11. Noninvasive brain stimulation improves language learning.

    Science.gov (United States)

    Flöel, Agnes; Rösser, Nina; Michka, Olesya; Knecht, Stefan; Breitenstein, Caterina

    2008-08-01

    Anodal transcranial direct current stimulation (tDCS) is a reliable technique to improve motor learning. We here wanted to test its potential to enhance associative verbal learning, a skill crucial for both acquiring new languages in healthy individuals and for language reacquisition after stroke-induced aphasia. We applied tDCS (20 min, 1 mA) over the posterior part of the left peri-sylvian area of 19 young right-handed individuals while subjects acquired a miniature lexicon of 30 novel object names. Every subject participated in one session of anodal tDCS, one session of cathodal tDCS, and one sham session in a randomized and double-blinded design with three parallel versions of the miniature lexicon. Outcome measures were learning speed and learning success at the end of each session, and the transfer to the subjects' native language after the respective stimulation. With anodal stimulation, subjects showed faster and better associative learning as compared to sham stimulation. Mood ratings, reaction times, and response styles were comparable between stimulation conditions. Our results demonstrate that anodal tDCS is a promising technique to enhance language learning in healthy adults and may also have the potential to improve language reacquisition after stroke.

  12. Vestibular stimulation for management of premenstrual syndrome

    Science.gov (United States)

    Johny, Minu; Kumar, Sai Sailesh; Rajagopalan, Archana; Mukkadan, Joseph Kurien

    2017-01-01

    Objectives: The present study was undertaken to observe the effectiveness of vestibular stimulation in the management of premenstrual syndrome (PMS). Materials and Methods: The present study was an experimental study; twenty female participants of age group 18–30 years were recruited in the present study. Conventional swing was used to administer vestibular stimulation. Variables were recorded before and after vestibular stimulation and compared. Results: Depression and stress scores are significantly decreased after 2 months of intervention. Anxiety scores decreased followed by vestibular stimulation. However, it is no statistically significant. Serum cortisol levels significantly decreased after 2 months of intervention. WHOQOL-BREF-transformed scores were not significantly changed followed by the intervention. However, psychological domain score (T2) and social relationships domain score (T3) were increased followed by intervention. Systolic blood pressure was significantly decreased after 2 months of intervention. No significant change was observed in diastolic pressure and pulse rate. Pain score was significantly decreased after 2 months of intervention. Mini mental status examination scores and spatial and verbal memory score were significantly improved followed by intervention. Conclusion: The present study provides preliminary evidence for implementing vestibular stimulation for management of PMS as a nonpharmacological therapy. Hence, we recommend further well-controlled, detailed studies in this area with higher sample size. PMID:28250680

  13. Stimulation of suicidal erythrocyte death by sulforaphane.

    Science.gov (United States)

    Alzoubi, Kousi; Calabrò, Salvatrice; Faggio, Caterina; Lang, Florian

    2015-03-01

    Sulforaphane, an isothiocyanate from cruciferous vegetable, counteracts malignancy. The effect is at least in part due to the stimulation of suicidal death or apoptosis of tumour cells. Mechanisms invoked in sulforaphane-induced apoptosis include mitochondrial depolarization and altered gene expression. Despite the lack of mitochondria and nuclei, erythrocytes may, similar to apoptosis of nucleated cells, enter eryptosis, a suicidal cell death characterized by cell shrinkage and phosphatidylserine translocation to the erythrocyte surface. Stimulators of eryptosis include increase of cytosolic Ca(2+)-activity ([Ca(2+)]i). This study explored whether sulforaphane stimulates eryptosis. Cell volume was estimated from forward scatter, phosphatidylserine exposure at the cell surface from annexin V binding and [Ca(2+)]i from Fluo-3 fluorescence. A 48-hr treatment of human erythrocytes with sulforaphane (50-100 μM) significantly decreased forward scatter, significantly increased the percentage of annexin V binding cells and significantly increased [Ca(2+)]i. The effect of sulforaphane (100 μM) on annexin V binding was significantly blunted but not abrogated by the removal of extracellular Ca(2+). Sulforaphane (100 μM) significantly increased ceramide formation. In conclusion, sulforaphane stimulates suicidal erythrocyte death or eryptosis, an effect at least partially, but not exclusively, due to the stimulation of Ca(2+) entry and ceramide formation. © 2014 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  14. Development of Receiver Stimulator for Auditory Prosthesis

    Directory of Open Access Journals (Sweden)

    K. Raja Kumar

    2010-05-01

    Full Text Available The Auditory Prosthesis (AP is an electronic device that can provide hearing sensations to people who are profoundly deaf by stimulating the auditory nerve via an array of electrodes with an electric current allowing them to understand the speech. The AP system consists of two hardware functional units such as Body Worn Speech Processor (BWSP and Receiver Stimulator. The prototype model of Receiver Stimulator for Auditory Prosthesis (RSAP consists of Speech Data Decoder, DAC, ADC, constant current generator, electrode selection logic, switch matrix and simulated electrode resistance array. The laboratory model of speech processor is designed to implement the Continuous Interleaved Sampling (CIS speech processing algorithm which generates the information required for electrode stimulation based on the speech / audio data. Speech Data Decoder receives the encoded speech data via an inductive RF transcutaneous link from speech processor. Twelve channels of auditory Prosthesis with selectable eight electrodes for stimulation of simulated electrode resistance array are used for testing. The RSAP is validated by using the test data generated by the laboratory prototype of speech processor. The experimental results are obtained from specific speech/sound tests using a high-speed data acquisition system and found satisfactory.

  15. Electrical Stimulation to Promote Peripheral Nerve Regeneration.

    Science.gov (United States)

    Willand, Michael P; Nguyen, May-Anh; Borschel, Gregory H; Gordon, Tessa

    2016-06-01

    Peripheral nerve injury afflicts individuals from all walks of life. Despite the peripheral nervous system's intrinsic ability to regenerate, many patients experience incomplete functional recovery. Surgical repair aims to expedite this recovery process in the most thorough manner possible. However, full recovery is still rarely seen especially when nerve injury is compounded with polytrauma where surgical repair is delayed. Pharmaceutical strategies supplementary to nerve microsurgery have been investigated but surgery remains the only viable option. Brief low-frequency electrical stimulation of the proximal nerve stump after primary repair has been widely investigated. This article aims to review the currently known biological basis for the regenerative effects of acute brief low-frequency electrical stimulation on axonal regeneration and outline the recent clinical applications of the electrical stimulation protocol to demonstrate the significant translational potential of this modality for repairing peripheral nerve injuries. The review concludes with a discussion of emerging new advancements in this exciting area of research. The current literature indicates the imminent clinical applicability of acute brief low-frequency electrical stimulation after surgical repair to effectively promote axonal regeneration as the stimulation has yielded promising evidence to maximize functional recovery in diverse types of peripheral nerve injuries. © The Author(s) 2015.

  16. Stimulants for the control of hedonic appetite

    Directory of Open Access Journals (Sweden)

    Alison Sally Poulton

    2016-04-01

    Full Text Available The focus of this paper is treatment of obesity in relation to the management of hedonic appetite. Obesity is a complex condition which may be potentiated by excessive reward seeking in combination with executive functioning deficits that impair cognitive control of behaviour. Stimulant medications address both reward deficiency and enhance motivation, as well as suppressing appetite. They have long been recognised to be effective for treating obesity. However, stimulants can be abused for their euphoric effect. They induce euphoria via the same neural pathway that underlies their therapeutic effect in obesity. For this reason they have generally not been endorsed for use in obesity. Among the stimulants, only phentermine (either alone or in combination with topiramate and bupropion (which has stimulant-like properties and is used in combination with naltrexone, are approved by the United States Food and Drug Administration (FDA for obesity, although dexamphetamine and methylpenidate are approved and widely used for treating attention deficit hyperactivity disorder (ADHD in adults and children. Experience gained over many years in the treatment of ADHD demonstrates that with careful dose titration, stimulants can be used safely. In obesity, improvement in mood and executive functioning could assist with the lifestyle changes necessary for weight control, acting synergistically with appetite suppression. The obesity crisis has reached the stage that strong consideration should be given to adequate utilisation of this effective and inexpensive class of drug.

  17. Single vs. dual mode stimulation in spinal cord stimulation - what is the difference?

    NARCIS (Netherlands)

    Manola, L.; Holsheimer, J.

    2006-01-01

    Objectives. Stimulation with dual percutaneous leads is often used in SCS. Either a single generator gives pulses to both leads simultaneously (single mode), or two generators give pulses to each lead alternately (dual mode) [1]. The aim was to compare theoretically the performance of these stimul

  18. Paired associative stimulation targeting the tibialis anterior muscle using either mono or biphasic transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Mrachacz-Kersting, Natalie; Stevenson, Andrew James Thomas

    2017-01-01

    Paired associative stimulation (PAS) protocols induce plastic changes within the motor cortex. The objectives of this study were to investigate PAS effects targeting the tibialis anterior (TA) muscle using a biphasic transcranial magnetic stimulation (TMS) pulse form and, to determine whether...

  19. Gender and injuries predict stimulant medication

    DEFF Research Database (Denmark)

    Dalsgaard, Søren; Leckman, James F.; Nielsen, Helena Skyt

    2014-01-01

    Objective: The purpose of this article was to examine whether injuries in early childhood and gender predict prescriptions of stimulant medication in three groups of children: With attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and other psychiatric disorders (OPD...... follow-up of all cases. We found that the number of injuries prior to diagnosis was associated with initiation of stimulant treatment in all three groups of patients. In addition, male gender predicted treatment with ADHD medications. Our results suggest that the number of injuries early in life prior......). Methods: This was a population-based study with prospective and complete follow-up of children with ADHD (n=11,553), ASD (n=9698), and OPD (n=48,468), of whom 61%, 16%, and 3%, respectively, were treated with stimulants. For all 69,719 individual children data on psychiatric diagnoses, injuries, and drug...

  20. Evaluation of Galvanic Vestibular Stimulation System

    Science.gov (United States)

    Kofman, I. S.; Warren, E.; DeSoto, R.; Moroney, G.; Chastain, J.; De Dios, Y. E.; Gadd, N.; Taylor, L.; Peters, B. T.; Allen, E.; hide

    2017-01-01

    Microgravity exposure results in an adaptive central reinterpretation of information from multiple sensory sources to produce a sensorimotor state appropriate for motor actions in this unique environment, but this new adaptive state is no longer appropriate for the 1-g gravitational environment on Earth. During these gravitational transitions, astronauts experience deficits in both perceptual and motor functions including impaired postural control, disruption in spatial orientation, impaired control of locomotion that include alterations in muscle activation variability, modified lower limb kinematics, alterations in head-trunk coordination as well as reduced dynamic visual acuity. Post-flight changes in postural and locomotor control might have adverse consequences if a rapid egress was required following a long-duration mission, where support personnel may not be available to aid crewmembers. The act of emergency egress includes, but is not limited to standing, walking, climbing a ladder, jumping down, monitoring displays, actuating discrete controls, operating auxiliary equipment, and communicating with Mission Control and recovery teams while maintaining spatial orientation, mobility and postural stability in order to escape safely. The average time to recover impaired postural control and functional mobility to preflight levels of performance has been shown to be approximately two weeks after long-duration spaceflight. The postflight alterations are due in part to central reinterpretation of vestibular information caused by exposure to microgravity. In this study we will use a commonly used technique of transcutaneous electrical stimulation applied across the vestibular end organs (galvanic vestibular stimulation, GVS) to disrupt vestibular function as a simulation of post-flight disturbances. The goal of this project is an engineering human-in-the-loop evaluation of a device that can degrade performance of functional tasks (e.g. to maintain upright balance

  1. [Transcranial direct current stimulation for depressive disorders].

    Science.gov (United States)

    Aust, S; Palm, U; Padberg, F; Bajbouj, M

    2015-12-01

    Major depressive disorders are one of the most prevalent psychiatric disorders worldwide but approximately 20-30 % of patients do not respond to standard guideline conform treatment. Recent neuroimaging studies in depressive patients revealed altered activation patterns in prefrontal brain areas and that successful cognitive behavioral therapy and psychopharmacological interventions are associated with a reversal of these neural alterations. Therefore, a direct modulation of prefrontal brain activation by non-invasive brain stimulation techniques, such as transcranial direct current stimulation (tDCS) seems to be a promising and innovative approach for the treatment of depressive disorders. In addition, recent neuropsychological findings indicated an augmentation of positive tDCS effects by simultaneous external activation of the stimulated brain area, for example by cognitive training tasks. Based on these findings, the possibility to augment cognitive-emotional learning processes during cognitive behavioral therapy by simultaneous tDCS to increase antidepressive therapeutic effects is discussed in this article.

  2. Conception of Electro-Stimulation System

    Directory of Open Access Journals (Sweden)

    Adil Salbi

    2014-10-01

    Full Text Available The aim of this work is to suggest a reliable solution of electro-stimulation making it possible to restore defective functions of the nervous systems among certain patients. This solution consists in creating a signal similar to that arriving of the central nervous system. Thus, work presented aims to design an electronic circuit of stimulation allowing the contraction of the muscle to restore its function by a biphasic train of electric impulse. This stimulator system is composed of a clock, an inverter and a logical sequencer which shifts the clock signal. The stage of power makes it possible to adapt the signals newcomers on a transformer booster coupled to a stage of order to regulate the amplitude of the impulse.

  3. Early experiences with tachycardia-triggered vagus nerve stimulation using the AspireSR stimulator.

    Science.gov (United States)

    El Tahry, Riëm; Hirsch, Martin; Van Rijckevorsel, Kenou; Santos, Susana Ferrao; de Tourtchaninoff, Marianne; Rooijakkers, Herbert; Coenen, Volker; Schulze-Bonhage, Andreas

    2016-06-01

    Many epilepsy patients treated with vagus nerve stimulation additionally use an "on-demand" function, triggering an extra stimulation to terminate a seizure or diminish its severity. Nevertheless, a substantial number of patients are not able to actively trigger stimulations by use of a magnet, due to the absence of an aura or inability for voluntary actions in the early phase of a seizure. To address this need, a novel implantable pulse generator, the AspireSR VNS system, was developed to provide automated ictal stimulation triggered by a seizure-detecting algorithm. We report our experience with three patients in assessing the functionality of ictal stimulation, illustrating the detection system in practice. Detection of ictal tachycardia and variable additional detections of physiological tachycardia depended on the individual seizure-detecting algorithm settings.

  4. Lubiprostone stimulates small intestinal mucin release

    Directory of Open Access Journals (Sweden)

    De Lisle Robert C

    2012-11-01

    Full Text Available Abstract Background Lubiprostone is a synthetic bicyclic fatty acid derivative of prostaglandin E1 (PGE1 used for chronic constipation. The best known action of lubiprostone is simulation of Cl- dependent fluid secretion. In a mouse model of the genetic disease cystic fibrosis, we previously showed that in vivo administration of lubiprostone resulted in greater mucus accumulation in the small intestine. The aim of this study was to directly test whether lubiprostone stimulates intestinal mucin release. Methods Mucin release was measured by mounting segments (4-5 cm of mouse proximal-mid small intestine in an organ bath, allowing access to the perfusate (luminal and the bath (serosal solutions. Nifedipine (10-6 M and indomethacin (10-5 M were included in all solutions to inhibit smooth muscle activity and endogenous prostaglandin production, respectively. The tissue was equilibrated under flow for 30 min, using the perfusate collected during the final 10 min of the equilibration period to measure unstimulated release rate. Stimulus was then added to either the perfusate or the bath and the perfusate was collected for another 30 min to measure the stimulated mucin release rate. Mucin in perfusates was quantified by periodic acid-Schiff's base dot-blot assay, using purified pig gastric mucin as a standard. Results When applied luminally at 1 μM lubiprostone was ineffective at stimulating mucin release. When added to the serosal solution, 1 μM lubiprostone stimulated mucin release to ~300% of the unstimulated rate. As a positive control, serosal 1 μM prostaglandin E2 increased mucin release to ~400% of the unstimulated rate. Conclusions These results support the idea that lubiprostone has prostaglandin-like actions on the intestine, which includes stimulation of mucin release. Stimulation of mucin release by lubiprostone may be protective in gastrointestinal conditions where loss of mucus is believed to contribute to pathogenesis. Thus, in

  5. Manual evaluation of residual curarization using double burst stimulation

    DEFF Research Database (Denmark)

    Drenck, N E; Ueda, N; Olsen, Niels Vidiendal;

    1989-01-01

    Double burst stimulation (DBS) is a new mode of stimulation developed to reveal residual neuromuscular blockade under clinical conditions. The stimulus consists of two short bursts of 50 Hz tetanic stimulation, separated by 750 ms, and the response to the stimulation is two short muscle contracti...

  6. Stimulated emission of surface plasmon polaritons

    CERN Document Server

    Noginov, M A; Mayy, M F; Ritzo, B A; Noginova, N; Podolskiy, V A

    2008-01-01

    We have observed laser-like emission of surface plasmon polaritons (SPPs) decoupled to the glass prism in an attenuated total reflection setup. SPPs were excited by optically pumped molecules in a polymeric film deposited on the top of the silver film. Stimulated emission was characterized by a distinct threshold in the input-output dependence and narrowing of the emission spectrum. The observed stimulated emission and corresponding to it compensation of the metallic absorption loss by gain enables many applications of metamaterials and nanoplasmonic devices.

  7. Effects of Vibrotactile Stimulation During Virtual Sandboarding

    DEFF Research Database (Denmark)

    Lind, Stine; Thomsen, Lui; Egebjerg, Mie;

    underneath the board. The study compared three conditions: no vibration, constant vibration and dynamic vibration. The results suggest that constant vibrotactile feedback led to significantly more compelling self-motion illusions and a higher degree of perceived realism, than the condition devoid......This poster details a within-subjects study (n=17) investigating the effects of vibrotactile stimulation on illusory self-motion, presence and perceived realism during an interactive sandboarding simulation. Vibrotactile feedback was delivered using a low frequency audio transducer mounted...... of vibrotactile feedback. No significant differences were found between the two conditions involving vibrotactile stimulation....

  8. Neural dynamics during repetitive visual stimulation

    Science.gov (United States)

    Tsoneva, Tsvetomira; Garcia-Molina, Gary; Desain, Peter

    2015-12-01

    Objective. Steady-state visual evoked potentials (SSVEPs), the brain responses to repetitive visual stimulation (RVS), are widely utilized in neuroscience. Their high signal-to-noise ratio and ability to entrain oscillatory brain activity are beneficial for their applications in brain-computer interfaces, investigation of neural processes underlying brain rhythmic activity (steady-state topography) and probing the causal role of brain rhythms in cognition and emotion. This paper aims at analyzing the space and time EEG dynamics in response to RVS at the frequency of stimulation and ongoing rhythms in the delta, theta, alpha, beta, and gamma bands. Approach.We used electroencephalography (EEG) to study the oscillatory brain dynamics during RVS at 10 frequencies in the gamma band (40-60 Hz). We collected an extensive EEG data set from 32 participants and analyzed the RVS evoked and induced responses in the time-frequency domain. Main results. Stable SSVEP over parieto-occipital sites was observed at each of the fundamental frequencies and their harmonics and sub-harmonics. Both the strength and the spatial propagation of the SSVEP response seem sensitive to stimulus frequency. The SSVEP was more localized around the parieto-occipital sites for higher frequencies (>54 Hz) and spread to fronto-central locations for lower frequencies. We observed a strong negative correlation between stimulation frequency and relative power change at that frequency, the first harmonic and the sub-harmonic components over occipital sites. Interestingly, over parietal sites for sub-harmonics a positive correlation of relative power change and stimulation frequency was found. A number of distinct patterns in delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz) and beta (15-30 Hz) bands were also observed. The transient response, from 0 to about 300 ms after stimulation onset, was accompanied by increase in delta and theta power over fronto-central and occipital sites, which returned to baseline

  9. Optically stimulated luminescence in retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Murray, A.S.

    2002-01-01

    Since the beginning of the 1990s the exploration of optically stimulated luminescence (OSL) in retrospective accident dosimetry has driven an intensive investigation and development programme at Riso into measurement facilities and techniques. This paper reviews some of the outcomes of this progr......Since the beginning of the 1990s the exploration of optically stimulated luminescence (OSL) in retrospective accident dosimetry has driven an intensive investigation and development programme at Riso into measurement facilities and techniques. This paper reviews some of the outcomes...

  10. Tinnitus treatment with sound stimulation during sleep.

    Science.gov (United States)

    M, Pedemonte; D, Drexler; S, Rodio; D, Geisinger; A, Bianco; D, Pol-Fernandes; V, Bernhardt

    2010-01-01

    A new strategy for idiopathic subjective tinnitus treatment - sound stimulation during sleep - has been applied. It was based on the acknowledgement that the auditory system also works during sleep, processing the incoming information. Eleven patients were stimulated every night during 6 months. The stimulus was a sound that mimetized the tinnitus and was fixed at the same tinnitus intensity, applied through an iPod. All patients decreased their tinnitus intensity in the first month of treatment (statistically significant), most of them in the first week. Tinnitus intensity continued decreasing in the following weeks; three patients presented periods of total silence.

  11. Functional electrical stimulation with surface electrodes

    Directory of Open Access Journals (Sweden)

    Bajd Tadej

    2008-01-01

    Full Text Available The review investigates the objective evidences of benefits derived from surface functional electrical stimulation (FES of lower and upper extremities for people after incomplete spinal cord injury (SCI and stroke. FES can offer noticeable benefits in walking ability. It can be efficiently combined with treadmill and body weight support. Voluntary muscle strength and endurance gain can be achieved through FES assisted gait training together with increased gait velocity in absence of electrical stimulator. Cyclic FES, FES augmented by biofeedback, and FES used in various daily activities can result in substantial improvements of the voluntary control of upper extremities.

  12. Field modeling for transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Thielscher, Axel; Antunes, Andre; Saturnino, Guilherme B

    2015-01-01

    Electric field calculations based on numerical methods and increasingly realistic head models are more and more used in research on Transcranial Magnetic Stimulation (TMS). However, they are still far from being established as standard tools for the planning and analysis in practical applications...... of TMS. Here, we start by delineating three main challenges that need to be addressed to unravel their full potential. This comprises (i) identifying and dealing with the model uncertainties, (ii) establishing a clear link between the induced fields and the physiological stimulation effects, and (iii...

  13. Clinical application of repetitive transcranial magnetic stimulation in stroke rehabilitation☆

    Science.gov (United States)

    Shin, Joonho; Yang, EunJoo; Cho, KyeHee; Barcenas, Carmelo L; Kim, Woo Jin; Min, Yusun; Paik, Nam-Jong

    2012-01-01

    Proper stimulation to affected cerebral hemisphere would promote the functional recovery of patients with stroke. Effects of repetitive transcranial magnetic stimulation on cortical excitability can be can be altered by the stimulation frequency, intensity and duration. There has been no consistent recognition regarding the best stimulation frequency and intensity. This study reviews the intervention effects of repetitive transcranial stimulation on motor impairment, dysphagia, visuospatial neglect and aphasia, and summarizes the stimulation frequency, intensity and area for repetitive transcranial magnetic stimulation to yield the best therapeutic effects. PMID:25745455

  14. Clinical application of repetitive transcranial magnetic stimulation in stroke rehabilitation

    Institute of Scientific and Technical Information of China (English)

    Joonho Shin; EunJoo Yang; KyeHee Cho; Carmelo L Barcenas; Woo Jin Kim; Yusun Min; Nam-Jong Paik

    2012-01-01

    Proper stimulation to affected cerebral hemisphere would promote the functional recovery of patients with stroke. Effects of repetitive transcranial magnetic stimulation on cortical excitability can be can be altered by the stimulation frequency, intensity and duration. There has been no consistent recognition regarding the best stimulation frequency and intensity. This study reviews the intervention effects of repetitive transcranial stimulation on motor impairment, dysphagia, visuospatial neglect and aphasia, and summarizes the stimulation frequency, intensity and area for repetitive transcranial magnetic stimulation to yield the best therapeutic effects.

  15. State of the Art: Novel Applications for Cortical Stimulation.

    Science.gov (United States)

    De Ridder, Dirk; Perera, Sanjaya; Vanneste, Sven

    2017-04-01

    Electrical stimulation via implanted electrodes that overlie the cortex of the brain is an upcoming neurosurgical technique that was hindered for a long time by insufficient knowledge of how the brain functions in a dynamic, physiological, and pathological way, as well as by technological limitations of the implantable stimulation devices. This paper provides an overview of cortex stimulation via implantable devices and introduces future possibilities to improve cortex stimulation. Cortex stimulation was initially used preoperatively as a technique to localize functions in the brain and only later evolved into a treatment technique. It was first used for pain, but more recently a multitude of pathologies are being targeted by cortex stimulation. These disorders are being treated by stimulating different cortical areas of the brain. Risks and complications are essentially similar to those related to deep brain stimulation and predominantly include haemorrhage, seizures, infection, and hardware failures. For cortex stimulation to fully mature, further technological development is required to predict its outcomes and improve stimulation designs. This includes the development of network science-based functional connectivity approaches, genetic analyses, development of navigated high definition transcranial alternating current stimulation, and development of pseudorandom stimulation designs for preventing habituation. In conclusion, cortex stimulation is a nascent but very promising approach to treating a variety of diseases, but requires further technological development for predicting outcomes, such as network science based functional connectivity approaches, genetic analyses, development of navigated transcranial electrical stimulation, and development of pseudorandom stimulation designs for preventing habituation. © 2017 International Neuromodulation Society.

  16. Coupling BCI and cortical stimulation for brain-state-dependent stimulation: Methods for spectral estimation in the presence of stimulation after-effects

    Directory of Open Access Journals (Sweden)

    Armin eWalter

    2012-11-01

    Full Text Available Brain-state-dependent stimulation combines brain-computer interfaces (BCI and cortical stimulation into one paradigm that allows the online decoding for example of movement intention from brain signals while simultaneously applying stimulation. If the BCI decoding is performed by spectral features, stimulation after-effects such as artefacts and evoked activity present a challenge for a successful implementation of brain-state-dependent stimulation because they can impair the detection of targeted brain states. Therefore, efficient and robust methods are needed to minimize the influence of the stimulation-induced effects on spectral estimation without violating the real-time constraints of the BCI.In this work, we compared 4 methods for spectral estimation with autoregressive (AR models in the presence of pulsed cortical stimulation. Using combined EEG-TMS as well as combined ECoG and epidural electrical stimulation, 3 patients performed a motor task using a sensorimotor-rhythm BCI. Three stimulation paradigms were varied between sessions: (1 no stimulation, (2 single stimulation pulses applied independently (open-loop or (3 coupled to the BCI output (closed-loop such that stimulation was given only while an intention to move was detected using neural data.We found that removing the stimulation after-effects by linear interpolation can introduce a bias in the estimation of the spectral power of the sensorimotor rhythm, leading to an overestimation of decoding performance in the closed-loop setting. We propose the use of the Burg algorithm for segmented data to deal with stimulation after-effects. This work shows that the combination of BCIs controlled with spectral features and cortical stimulation in a closed-loop fashion is possible when the influence of stimulation after-effects on spectral estimation is minimized.

  17. Quantum theory of laser-stimulated desorption

    Science.gov (United States)

    Slutsky, M. S.; George, T. F.

    1978-01-01

    A quantum theory of laser-stimulated desorption (LSDE) is presented and critically analyzed. It is shown how LSDE depends on laser-pulse characteristics and surface-lattice dynamics. Predictions of the theory for a Debye model of the lattice dynamics are compared to recent experimental results.

  18. Neuromagnetic effects of pico-Tesla stimulation.

    Science.gov (United States)

    Troebinger, Luzia; Anninos, Photios; Barnes, Gareth

    2015-09-01

    We used a double-blind experimental design to look for an effect of pico-Tesla magnetic stimulation in healthy subjects. Pico-Tesla stimulation is thought to increase the dominant frequency of 2-7 Hz oscillations in the human brain. We used magnetoencephalography to measure resting state brain activity. Each subject had two separate recording sessions consisting of three runs in between which they were given real or sham pT stimulation. We then tried to predict the real and sham stimulation sessions based on changes in the mean peak frequency in the 2-7 Hz band. Our predictions for these individual runs were 8 out of 14 at chance level (p = 0.39). After unblinding, we found no significant effect (p = 0.11) of an increase in the frequency range (2-7 Hz) across the subject group. Finally, we performed a Bayesian model comparison between the effect size predicted from previous clinical studies and a null model. Even though this study had a sensitivity advantage of at least one order of magnitude over previous work, we found the null model to be significantly (2000 times) more likely.

  19. Aromatase inhibitors in stimulated IVF cycles

    Directory of Open Access Journals (Sweden)

    Tournaye Herman

    2011-06-01

    Full Text Available Abstract Aromatase inhibitors have been introduced as a new treatment modality that could challenge clomiphene citrate as an ovulation induction regiment in patients with PCOS. Although several randomized trials have been conducted regarding their use as ovulation induction agents, only few trials are available regarding their efficacy in IVF stimulated cycles. Current available evidence support that letrozole may have a promising role in stimulated IVF cycles, either when administered during the follicular phase for ovarian stimulation. Especially for women with poor ovarian response, letrozole appears to have the potential to increase clinical pregnancy rates when combined with gonadotropins, whereas at the same time reduces the total gonadotropin dose required for ovarian stimulation. However, given that in all of the trials letrozole has been administered in GnRH antagonist cycles, it is intriguing to test in the future how it may perform when used in GnRH agonist cycles. Finally administration of letrozole during luteal phase in IVF cycles offers another treatment modality for patients at high risk for OHSS taking into account that it drastically reduces estradiol levels

  20. Ethical issues in deep brain stimulation

    NARCIS (Netherlands)

    M.H.N. Schermer (Maartje)

    2011-01-01

    textabstractDeep brain stimulation (DBS) is currently used to treat neurological disorders like Parkinson's disease, essential tremor, and dystonia, and is explored as an experimental treatment for psychiatric disorders like major depression and obsessive compulsive disorder. This mini review discus

  1. Stimulated secondary emission from semiconductor microcavities

    DEFF Research Database (Denmark)

    Østergaard, John Erland; Mizeikis, V.; Langbein, Wolfgang Werner

    2001-01-01

    We find strong influence of final-state stimulation on the time-resolved light emission dynamics from semiconductor microcavities after pulsed excitation allowing angle-resonant polariton-polariton scattering on the lower-polariton branch. The polariton dynamics can be controlled by injection of ...

  2. Social Early Stimulation of Trisomy-21 Babies

    Science.gov (United States)

    Aparicio, Maria Teresa Sanz; Balana, Javier Menendez

    2003-01-01

    This study was initiated with twenty Down's syndrome babies to verify whether subjects undergoing social early stimulation would benefit from this type of treatment. An experimental study was designed with two training groups: visual or written instructions. The analyses of the results established statistically significant differences in the…

  3. Stimulant ADHD Medications -- Methylphenidate and Amphetamines

    Science.gov (United States)

    ... to improve ADHD symptoms along with the patient’s self-esteem, thinking ability, and social and family interactions. Do ... that stimulants prescribed to treat a child’s or adolescent’s ADHD could affect an individual’s vulnerability to developing ...

  4. Anal sphincter responses after perianal electrical stimulation

    DEFF Research Database (Denmark)

    Pedersen, Ejnar; Klemar, B; Schrøder, H D

    1982-01-01

    By perianal electrical stimulation and EMG recording from the external anal sphincter three responses were found with latencies of 2-8, 13-18 and 30-60 ms, respectively. The two first responses were recorded in most cases. They were characterised by constant latency and uniform pattern, were...

  5. STIMULATION TECHNOLOGIES FOR DEEP WELL COMPLETIONS

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Wolhart

    2003-06-01

    The Department of Energy (DOE) is sponsoring a Deep Trek Program targeted at improving the economics of drilling and completing deep gas wells. Under the DOE program, Pinnacle Technologies is conducting a project to evaluate the stimulation of deep wells. The objective of the project is to assess U.S. deep well drilling & stimulation activity, review rock mechanics & fracture growth in deep, high pressure/temperature wells and evaluate stimulation technology in several key deep plays. Phase 1 was recently completed and consisted of assessing deep gas well drilling activity (1995-2007) and an industry survey on deep gas well stimulation practices by region. Of the 29,000 oil, gas and dry holes drilled in 2002, about 300 were drilled in the deep well; 25% were dry, 50% were high temperature/high pressure completions and 25% were simply deep completions. South Texas has about 30% of these wells, Oklahoma 20%, Gulf of Mexico Shelf 15% and the Gulf Coast about 15%. The Rockies represent only 2% of deep drilling. Of the 60 operators who drill deep and HTHP wells, the top 20 drill almost 80% of the wells. Six operators drill half the U.S. deep wells. Deep drilling peaked at 425 wells in 1998 and fell to 250 in 1999. Drilling is expected to rise through 2004 after which drilling should cycle down as overall drilling declines.

  6. Strigolactones stimulate internode elongation independently of gibberellins.

    Science.gov (United States)

    de Saint Germain, Alexandre; Ligerot, Yasmine; Dun, Elizabeth A; Pillot, Jean-Paul; Ross, John J; Beveridge, Christine A; Rameau, Catherine

    2013-10-01

    Strigolactone (SL) mutants in diverse species show reduced stature in addition to their extensive branching. Here, we show that this dwarfism in pea (Pisum sativum) is not attributable to the strong branching of the mutants. The continuous supply of the synthetic SL GR24 via the root system using hydroponics can restore internode length of the SL-deficient rms1 mutant but not of the SL-response rms4 mutant, indicating that SLs stimulate internode elongation via RMS4. Cytological analysis of internode epidermal cells indicates that SLs control cell number but not cell length, suggesting that SL may affect stem elongation by stimulating cell division. Consequently, SLs can repress (in axillary buds) or promote (in the stem) cell division in a tissue-dependent manner. Because gibberellins (GAs) increase internode length by affecting both cell division and cell length, we tested if SLs stimulate internode elongation by affecting GA metabolism or signaling. Genetic analyses using SL-deficient and GA-deficient or DELLA-deficient double mutants, together with molecular and physiological approaches, suggest that SLs act independently from GAs to stimulate internode elongation.

  7. Multimodal pain stimulation of the gastrointestinal tract

    Institute of Scientific and Technical Information of China (English)

    Asbjφrn Mohr Drewes; Hans Gregersen

    2006-01-01

    Understanding and characterization of pain and other sensory symptoms are among the most important issues in the diagnosis and assessment of patient with gastrointestinal disorders. Methods to evoke and assess experimental pain have recently developed into a new area with the possibility for multimodal stimulation (e.g.,electrical, mechanical, thermal and chemical stimulation)of different nerves and pain pathways in the human gut. Such methods mimic to a high degree the pain experienced in the clinic. Multimodal pain methods have increased our basic understanding of different peripheral receptors in the gut in health and disease. Together with advanced muscle analysis, the methods have increased our understanding of receptors sensitive to mechanical,chemical and temperature stimuli in diseases, such as systemic sclerosis and diabetes. The methods can also be used to unravel central pain mechanisms, such as those involved in allodynia, hyperalgesia and referred pain. Abnormalities in central pain mechanisms are often seen in patients with chronic gut pain and hence methods relying on multimodal pain stimulation may help to understand the symptoms in these patients.Sex differences have been observed in several diseases of the gut, and differences in central pain processing between males and females have been hypothesized using multimodal pain stimulations. Finally, multimodal methods have recently been used to gain more insight into the effect of drugs against pain in the GI tract.Hence, the multimodal methods undoubtedly represents a major step forward in the future characterization and treatment of patients with various diseases of the gut.

  8. Optically stimulated luminescence techniques in retrospective dosimetry

    DEFF Research Database (Denmark)

    Bøtter-Jensen, L.; Murray, A.S.

    2001-01-01

    Optically stimulated luminescence signals from natural quartz and feldspar are now used routinely in dating geological and archaeological materials. More recently they have also been employed in accident dosimetry, i.e. the retrospective assessment of doses received as a result of a nuclear...

  9. Ovarian hyper stimulation syndrome: a case report

    Directory of Open Access Journals (Sweden)

    Arti Patidar

    2016-07-01

    Full Text Available We present here a rare case ovarian hyper stimulation syndrome. In the case patient came with complain of abdominal pain, distension, nausea, vomiting with known case of secondary infertility. [Int J Reprod Contracept Obstet Gynecol 2016; 5(7.000: 2418-2420

  10. Spinal cord stimulation in chronic pain syndromes

    NARCIS (Netherlands)

    ten Vaarwerk, IAM; Staal, MJ

    1998-01-01

    Spinal cord stimulation (SCS) has been used for more than 30 years now, and although it has shown to be effective under certain well-described conditions of chronic pain, conclusive evidence on its effectiveness is still sparse. There is a need for more prospective and methodological good studies, i

  11. Computer Games Functioning as Motivation Stimulants

    Science.gov (United States)

    Lin, Grace Hui Chin; Tsai, Tony Kung Wan; Chien, Paul Shih Chieh

    2011-01-01

    Numerous scholars have recommended computer games can function as influential motivation stimulants of English learning, showing benefits as learning tools (Clarke and Dede, 2007; Dede, 2009; Klopfer and Squire, 2009; Liu and Chu, 2010; Mitchell, Dede & Dunleavy, 2009). This study aimed to further test and verify the above suggestion,…

  12. Stimulating reflection through engagement in social relationships

    NARCIS (Netherlands)

    Rajagopal, Kamakshi; Verjans, Steven; Van Bruggen, Jan; Sloep, Peter

    2011-01-01

    Rajagopal, K., Verjans, S., Van Bruggen, J., & Sloep, P. B. (2011). Stimulating reflection through engagement in social relationships. In W. Reinhardt, T. D. Ullmann, P. Scott, V. Pammer, O. Conlan, & A. J. Berlanga (Eds.), Proceedings of the 1st European Workshop on Awareness and Reflection in

  13. Heart rate control via vagus nerve stimulation

    NARCIS (Netherlands)

    Buschman, Hendrik P.; Storm, Corstiaan J.; Duncker, Dirk J.; Verdouw, Pieter D.; Aa, van der Hans E.; Kemp, van der Peter

    2006-01-01

    Objectives: There is ample and well-established evidence that direct electrical stimulation of the vagus nerve can change heart rate in animals and humans. Since tachyarrhythmias cannot always be controlled through medication, we sought, in this pilot study, to elucidate whether a clinical implantab

  14. Fidget Blankets: A Sensory Stimulation Outreach Program.

    Science.gov (United States)

    Kroustos, Kelly Reilly; Trautwein, Heidi; Kerns, Rachel; Sobota, Kristen Finley

    2016-01-01

    Behavioral and Psychological Symptoms of Dementia (BPSD) include behaviors such as aberrant motor behavior, agitation, anxiety, apathy, delusions, depression, disinhibition, elation, hallucinations, irritability, and sleep or appetite changes. A student-led project to provide sensory stimulation in the form of "fidget blankets" developed into a community outreach program. The goal was to decrease the use of antipsychotics used for BPSD.

  15. Peripheral neural activity recording and stimulation system.

    Science.gov (United States)

    Loi, D; Carboni, C; Angius, G; Angotzi, G N; Barbaro, M; Raffo, L; Raspopovic, S; Navarro, X

    2011-08-01

    This paper presents a portable, embedded, microcontroller-based system for bidirectional communication (recording and stimulation) between an electrode, implanted in the peripheral nervous system, and a host computer. The device is able to record and digitize spontaneous and/or evoked neural activities and store them in data files on a PC. In addition, the system has the capability of providing electrical stimulation of peripheral nerves, injecting biphasic current pulses with programmable duration, intensity, and frequency. The recording system provides a highly selective band-pass filter from 800 Hz to 3 kHz, with a gain of 56 dB. The amplification range can be further extended to 96 dB with a variable gain amplifier. The proposed acquisition/stimulation circuitry has been successfully tested through in vivo measurements, implanting a tf-LIFE electrode in the sciatic nerve of a rat. Once implanted, the device showed an input referred noise of 0.83 μVrms, was capable of recording signals below 10 μ V, and generated muscle responses to injected stimuli. The results demonstrate the capability of processing and transmitting neural signals with very low distortion and with a power consumption lower than 1 W. A graphic, user-friendly interface has been developed to facilitate the configuration of the entire system, providing the possibility to activate stimulation and monitor recordings in real time.

  16. Investigating Tactile Stimulation in Symbiotic Systems

    DEFF Research Database (Denmark)

    Orso, Valeria; Mazza, Renato; Gamberini, Luciano

    2017-01-01

    The core characteristics of tactile stimuli, i.e., recognition reliability and tolerance to ambient interference, make them an ideal candidate to be integrated into a symbiotic system. The selection of the appropriate stimulation is indeed important in order not to hinder the interaction from the...

  17. Stimulating Strategically Aligned Behaviour among Employees

    NARCIS (Netherlands)

    C.B.M. van Riel (Cees); G.A.J.M. Berens (Guido); M. Dijkstra (Majorie)

    2008-01-01

    textabstractStrategically aligned behaviour (SAB), i.e., employee action that is consistent with the company’s strategy, is of vital importance to companies. This study provides insights into the way managers can promote such behaviour among employees by stimulating employee motivation and by inform

  18. Stimulating Strategically Aligned Behaviour Among Employees

    NARCIS (Netherlands)

    C.B.M. van Riel (Cees); G.A.J.M. Berens (Guido); M. Dijkstra (Majorie)

    2007-01-01

    textabstractIn recent years it has become increasingly important for companies to ensure strategically aligned behaviour, i.e., employee actions that are consistent with the company’s strategy. This study provides insights into the way companies can stimulate such behaviour through motivating and in

  19. Motor-Cognitive Stimulation of the Elderly

    Science.gov (United States)

    Cao, Ana Rey; Lacruz, Inmaculada Canales; Pais, Maria Ines Taboas

    2011-01-01

    This article shows the cognitive and motor-perceptive effects of the application of a cognitive stimulating program through motor function on 234 elderly people. The assessment was carried out prior to and after the program. Significant improvements in the experimental group were observed (p [less than or equal to] 0.05) in six of the eight…

  20. Social Early Stimulation of Trisomy-21 Babies

    Science.gov (United States)

    Aparicio, Maria Teresa Sanz; Balana, Javier Menendez

    2003-01-01

    This study was initiated with twenty Down's syndrome babies to verify whether subjects undergoing social early stimulation would benefit from this type of treatment. An experimental study was designed with two training groups: visual or written instructions. The analyses of the results established statistically significant differences in the…

  1. Stimulating reflection through engagement in social relationships

    NARCIS (Netherlands)

    Rajagopal, Kamakshi; Verjans, Steven; Van Bruggen, Jan; Sloep, Peter

    2011-01-01

    Rajagopal, K., Verjans, S., Van Bruggen, J., & Sloep, P. B. (2011). Stimulating reflection through engagement in social relationships. In W. Reinhardt, T. D. Ullmann, P. Scott, V. Pammer, O. Conlan, & A. J. Berlanga (Eds.), Proceedings of the 1st European Workshop on Awareness and Reflection in Lear

  2. Optically stimulated luminescence dating of young sediments

    DEFF Research Database (Denmark)

    Madsen, A.T.; Murray, A.S.

    2009-01-01

    Optically stimulated luminescence (OSL) dating of young (< 1000 years) sediments is used increasingly in a wide variety of late-Holocene studies as a mean of establishing contemporary sedimentation rates or the timing of sediment deposition. This paper provides a summary of the basic principles o...

  3. Motor cortex stimulation in Parkinson's disease.

    Science.gov (United States)

    De Rose, Marisa; Guzzi, Giusy; Bosco, Domenico; Romano, Mary; Lavano, Serena Marianna; Plastino, Massimiliano; Volpentesta, Giorgio; Marotta, Rosa; Lavano, Angelo

    2012-01-01

    Motor Cortex Stimulation (MCS) is less efficacious than Deep Brain Stimulation (DBS) in Parkinson's disease. However, it might be proposed to patients excluded from DBS or unresponsive to DBS. Ten patients with advanced PD underwent unilateral MCS contralaterally to the worst clinical side. A plate electrode was positioned over the motor cortex in the epidural space through single burr hole after identification of the area with neuronavigation and neurophysiological tests. Clinical assessment was performed by total UPDRS, UPDRS III total, UPDRS III-items 27-31, UPDRS IV, and UPDRS II before implantation in off-medication and on-medication states and after surgery at 1, 3, 6, 12, 18, 24, and 36 months in on-medication/on-stimulation and off-medication/on-stimulation states. We assessed changes of quality of life, throughout the Parkinson's disease quality of life scale (PDQoL-39), and the dose of anti-Parkinson's disease medications, throughout the Ldopa equivalent daily dose (LEDD). During off-medication state, we observed moderate and transitory reduction of total UPDRS and UPDRS total scores and significant and long-lasting improvement in UPDRS III items 27-31 score for axial symptoms. There was marked reduction of UPDRS IV score and LEDD. PDQL-39 improvement was also significant. No important complications and adverse events occurred.

  4. Motor Cortex Stimulation in Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Marisa De Rose

    2012-01-01

    Full Text Available Motor Cortex Stimulation (MCS is less efficacious than Deep Brain Stimulation (DBS in Parkinson's disease. However, it might be proposed to patients excluded from DBS or unresponsive to DBS. Ten patients with advanced PD underwent unilateral MCS contralaterally to the worst clinical side. A plate electrode was positioned over the motor cortex in the epidural space through single burr hole after identification of the area with neuronavigation and neurophysiological tests. Clinical assessment was performed by total UPDRS, UPDRS III total, UPDRS III-items 27–31, UPDRS IV, and UPDRS II before implantation in off-medication and on-medication states and after surgery at 1, 3, 6, 12, 18, 24, and 36 months in on-medication/on-stimulation and off-medication/on-stimulation states. We assessed changes of quality of life, throughout the Parkinson's disease quality of life scale (PDQoL-39, and the dose of anti-Parkinson's disease medications, throughout the Ldopa equivalent daily dose (LEDD. During off-medication state, we observed moderate and transitory reduction of total UPDRS and UPDRS total scores and significant and long-lasting improvement in UPDRS III items 27–31 score for axial symptoms. There was marked reduction of UPDRS IV score and LEDD. PDQL-39 improvement was also significant. No important complications and adverse events occurred.

  5. Ultrasound stimulation of mandibular bone defect healing

    NARCIS (Netherlands)

    Schortinghuis, Jurjen

    2004-01-01

    The conclusions of the experimental work presented in this thesis are: 1. Low intensity pulsed ultrasound is not effective in stimulating bone growth into a rat mandibular defect, either with or without the use of osteoconductive membranes. 2. Low intensity pulsed ultrasound does not seem to have an

  6. Extra Stimulation in Intermediate Grade Reading.

    Science.gov (United States)

    Mason, George E.

    Three types of extra stimulation in reading are discussed: extra teacher time devoted to teaching reading, extra student time devoted to practice in reading, and extra motivation and reinforcement leading to greater amounts of student reading outside the school. Problems are created (1) when teaching time spent on reading is increased in the…

  7. Gastric applications of electrical field stimulation.

    LENUS (Irish Health Repository)

    Hogan, Aisling M

    2012-02-01

    Advances in clinical applications of electricity have been vast since the launch of Hayman\\'s first cardiac pacemaker more than 70 years ago. Gastric electrical stimulation devices have been recently licensed for treatment of gastroparesis and preliminary studies examining their potential for use in refractory obesity yield promising results.

  8. Deep Brain Stimulation - the challenges ahead

    NARCIS (Netherlands)

    Heida, T.; Holsheimer, J.; Geelen, J.A.G.; Veltink, P.H.

    2005-01-01

    Parkinson’s disease (PD) is characterized by progressive loss of dopamine neurons in the pars compacta of the substantia nigra, which results in reduced activity in the thalamus. Clinically effective deep brain stimulation (DBS) has been achieved with electrode contacts in the anterior- dorsal subth

  9. Growth stimulation of Brevibacterium sp. by siderophores

    NARCIS (Netherlands)

    Noordman, W.H.; Reissbrodt, R.; Bongers, R.S.; Rademaker, J.L.W.; Bockelmann, W.; Smit, G.

    2006-01-01

    To assess which types of siderophores are typically produced by Brevibacterium and how siderophore production and utilization traits are distributed within this genus. Methods and Results: During co-cultivation experiments it was found that growth of B. linens Br5 was stimulated by B. linens NIZO B1

  10. Evaluation of intradural stimulation efficiency and selectivity in a computational model of spinal cord stimulation.

    Directory of Open Access Journals (Sweden)

    Bryan Howell

    Full Text Available Spinal cord stimulation (SCS is an alternative or adjunct therapy to treat chronic pain, a prevalent and clinically challenging condition. Although SCS has substantial clinical success, the therapy is still prone to failures, including lead breakage, lead migration, and poor pain relief. The goal of this study was to develop a computational model of SCS and use the model to compare activation of neural elements during intradural and extradural electrode placement. We constructed five patient-specific models of SCS. Stimulation thresholds predicted by the model were compared to stimulation thresholds measured intraoperatively, and we used these models to quantify the efficiency and selectivity of intradural and extradural SCS. Intradural placement dramatically increased stimulation efficiency and reduced the power required to stimulate the dorsal columns by more than 90%. Intradural placement also increased selectivity, allowing activation of a greater proportion of dorsal column fibers before spread of activation to dorsal root fibers, as well as more selective activation of individual dermatomes at different lateral deviations from the midline. Further, the results suggest that current electrode designs used for extradural SCS are not optimal for intradural SCS, and a novel azimuthal tripolar design increased stimulation selectivity, even beyond that achieved with an intradural paddle array. Increased stimulation efficiency is expected to increase the battery life of implantable pulse generators, increase the recharge interval of rechargeable implantable pulse generators, and potentially reduce stimulator volume. The greater selectivity of intradural stimulation may improve the success rate of SCS by mitigating the sensitivity of pain relief to malpositioning of the electrode. The outcome of this effort is a better quantitative understanding of how intradural electrode placement can potentially increase the selectivity and efficiency of SCS

  11. Mechanism of orientation of stimulating currents in magnetic brain stimulation (abstract)

    Science.gov (United States)

    Ueno, S.; Matsuda, T.

    1991-04-01

    We made a functional map of the human motor cortex related to the hand and foot areas by stimulating the human brain with a focused magnetic pulse. We observed that each functional area in the cortex has an optimum direction for which stimulating currents can produce neural excitation. The present report focuses on the mechanism which is responsible for producing this anisotropic response to brain stimulation. We first obtained a functional map of the brain related to the left ADM (abductor digiti minimi muscles). When the stimulating currents were aligned in the direction from the left to the right hemisphere, clear EMG (electromyographic) responses were obtained only from the left ADM to magnetic stimulation of both hemisphere. When the stimulating currents were aligned in the direction from the right to the left hemisphere, clear EMG signals were obtained only from the right ADM to magnetic stimulation of both hemisphere. The functional maps of the brain were sensitive to changes in the direction of the stimulating currents. To explain the phenomena obtained in the experiments, we developed a model of neural excitation elicited by magnetic stimulation. When eddy currents which are induced by pulsed magnetic fields flow in the direction from soma to the distal part of neural fiber, depolarized area in the distal part are excited, and the membrane excitation propagates along the nerve fiber. In contrast, when the induced currents flow in the direction from the distal part to soma, hyperpolarized parts block or inhibit neural excitation even if the depolarized parts near the soma can be excited. The model explains our observation that the orientation of the induced current vectors reflect both the functional and anatomical organization of the neural fibers in the brain.

  12. Simultaneous application of slow-oscillation transcranial direct current stimulation and theta burst stimulation prolongs continuous theta burst stimulation-induced suppression of corticomotor excitability in humans.

    Science.gov (United States)

    Doeltgen, Sebastian H; McAllister, Suzanne M; Ridding, Michael C

    2012-09-01

    The objective of this study was to assess whether the simultaneous application of slow-oscillation transcranial direct current stimulation enhances the neuroplastic response to transcranial magnetic theta burst stimulation. Motor evoked potential amplitude was assessed at baseline and at regular intervals up to 60 min following continuous theta burst stimulation, slow-oscillation transcranial direct current stimulation, and the simultaneous application of these paradigms. In addition, the electroencephalographic power spectra of slow and fast delta, and theta frequency bands recorded over the motor cortex were analyzed prior to and up to 5 min following each intervention. There was longer-lasting motor evoked potential suppression following the simultaneous application of continuous theta burst stimulation and slow-oscillation transcranial direct current stimulation compared with when continuous theta burst stimulation was applied alone. Slow-oscillation transcranial direct current stimulation applied alone did not modulate the motor evoked potential amplitude. No significant changes in spectral power were observed following slow-oscillation transcranial direct current stimulation. Simultaneous application of continuous theta burst stimulation and slow-oscillation transcranial direct current stimulation may provide an approach to prolong the induction of neuroplastic changes in motor cortical circuits by repetitive transcranial magnetic brain stimulation.

  13. Rabbits immunized with thyroid-stimulating hormone produce autoantiidiotypic thyroid-stimulating antibodies.

    OpenAIRE

    Beall, G N; Rapoport, B; Chopra, I J; Kruger, S R

    1985-01-01

    We immunized rabbits with thyroid-stimulating hormone (TSH) to investigate the hypothesis that such immunization could result in production of thyroid-stimulating autoantiidiotypic antibodies to anti-TSH. Thyroid-stimulating immunoglobulin (TSI) appeared in the serum of several rabbits after immunization. At 160 d, TSI equivalent to 6-18 microU TSH/1.5 mg IgG was present in two of six human (h)TSH-, two of six hTSH beta chain-, and two of the four surviving bovine (b)TSH-immunized animals. Co...

  14. Geothermal reservoir categorization and stimulation study

    Energy Technology Data Exchange (ETDEWEB)

    Overton, H.L.; Hanold, R.J.

    1977-07-01

    Analyses of the fraction of geothermal wells that are dry (dry-hole fraction) indicate that geothermal reservoirs can be fitted into four basic categories: (i) Quaternary to late Tertiary sediments (almost no dry holes); (ii) Quaternary to late Tertiary extrusives (approximately 20 percent dry holes); (iii) Mesozoic or older metamorphic rocks (approximately 25-30 percent dry holes); and (iv) Precambrian or younger rocks (data limited to Roosevelt Springs where 33 percent of the wells were dry). Failure of geothermal wells to flow economically is due mainly to low-permeability formations in unfractured regions. Generally the permeability correlates inversely with the temperature-age product and directly with the original rock porosity and pore size. However, this correlation fails whenever high-stress fields provide vertical fracturing or faulting, and it is the high-stress/low-permeability category that is most amenable to artificial stimulation by hydraulic fracturing, propellant fracturing, or chemical explosive fracturing. Category (i) geothermal fields (e.g., Cerro Prieto, Mexico; Niland, CA; East Mesa, CA) are not recommended for artificial stimulation because these younger sediments almost always produce warm or hot water. Most geothermal fields fit into category (ii) (e.g., Wairakei, New Zealand; Matsukawa, Japan; Ahuachapan, El Salvador) and in the case of Mt. Home, ID, and Chandler, AZ, possess some potential for stimulation. The Geysers is a category (iii) field, and its highly stressed brittle rocks should make this site amenable to stimulation by explosive fracturing techniques. Roosevelt Springs, UT, well 9-1 is in category (iv) and is a flow failure. It represents a prime candidate for stimulation by hydraulic fracturing because it has a measured temperature of 227/sup 0/C, is cased and available for experimentation, and is within 900 m of an excellent geothermal producing well.

  15. Tissue damage thresholds during therapeutic electrical stimulation

    Science.gov (United States)

    Cogan, Stuart F.; Ludwig, Kip A.; Welle, Cristin G.; Takmakov, Pavel

    2016-04-01

    Objective. Recent initiatives in bioelectronic modulation of the nervous system by the NIH (SPARC), DARPA (ElectRx, SUBNETS) and the GlaxoSmithKline Bioelectronic Medicines effort are ushering in a new era of therapeutic electrical stimulation. These novel therapies are prompting a re-evaluation of established electrical thresholds for stimulation-induced tissue damage. Approach. In this review, we explore what is known and unknown in published literature regarding tissue damage from electrical stimulation. Main results. For macroelectrodes, the potential for tissue damage is often assessed by comparing the intensity of stimulation, characterized by the charge density and charge per phase of a stimulus pulse, with a damage threshold identified through histological evidence from in vivo experiments as described by the Shannon equation. While the Shannon equation has proved useful in assessing the likely occurrence of tissue damage, the analysis is limited by the experimental parameters of the original studies. Tissue damage is influenced by factors not explicitly incorporated into the Shannon equation, including pulse frequency, duty cycle, current density, and electrode size. Microelectrodes in particular do not follow the charge per phase and charge density co-dependence reflected in the Shannon equation. The relevance of these factors to tissue damage is framed in the context of available reports from modeling and in vivo studies. Significance. It is apparent that emerging applications, especially with microelectrodes, will require clinical charge densities that exceed traditional damage thresholds. Experimental data show that stimulation at higher charge densities can be achieved without causing tissue damage, suggesting that safety parameters for microelectrodes might be distinct from those defined for macroelectrodes. However, these increased charge densities may need to be justified by bench, non-clinical or clinical testing to provide evidence of device

  16. Proinflammatory mediators stimulate neutrophil-directed angiogenesis.

    LENUS (Irish Health Repository)

    McCourt, M

    2012-02-03

    BACKGROUND: Vascular endothelial growth factor (VEGF; vascular permeability factor) is one of the most potent proangiogenic cytokines, and it plays a central role in mediating the process of angiogenesis or new blood vessel formation. Neutrophils (PMNs) recently have been shown to produce VEGF. HYPOTHESIS: The acute inflammatory response is a potent stimulus for PMN-directed angiogenesis. METHODS: Neutrophils were isolated from healthy volunteers and stimulated with lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), and anti-human Fas monoclonal antibody. Culture supernatants were assayed for VEGF using enzyme-linked immunosorbent assays. Culture supernatants from LPS- and TNF-alpha-stimulated PMNs were then added to human umbilical vein endothelial cells and human microvessel endothelial cells and assessed for endothelial cell proliferation using 5-bromodeoxyuridine labeling. Tubule formation was also assessed on MATRIGEL basement membrane matrix. Neutrophils were lysed to measure total VEGF release, and VEGF expression was detected using Western blot analysis. RESULTS: Lipopolysaccharide and TNF-alpha stimulation resulted in significantly increased release of PMN VEGF (532+\\/-49 and 484+\\/-80 pg\\/mL, respectively; for all, presented as mean +\\/- SEM) compared with control experiments (32+\\/-4 pg\\/mL). Interleukin 6 and Fas had no effect. Culture supernatants from LPS- and TNF-alpha-stimulated PMNs also resulted in significant increases (P<.005) in macrovascular and microvascular endothelial cell proliferation and tubule formation. Adding anti-human VEGF-neutralizing polyclonal antibody to stimulated PMN supernatant inhibited these effects. Total VEGF release following cell lysis and Western blot analysis suggests that the VEGF is released from an intracellular store. CONCLUSION: Activated human PMNs are directly angiogenic by releasing VEGF, and this has important implications for inflammation, capillary leak syndrome

  17. Interaction of transcranial magnetic stimulation and electrical transmastoid stimulation in human subjects

    DEFF Research Database (Denmark)

    Taylor, Janet L; Petersen, Nicolas Caesar; Butler, Jane E

    2002-01-01

    Transcranial magnetic stimulation activates corticospinal neurones directly and transsynaptically and hence, activates motoneurones and results in a response in the muscle. Transmastoid stimulation results in a similar muscle response through activation of axons in the spinal cord. This study...... was designed to determine whether the two stimuli activate the same descending axons. Responses to transcranial magnetic stimuli paired with electrical transmastoid stimuli were examined in biceps brachii in human subjects. Twelve interstimulus intervals (ISIs) from -6 ms (magnet before transmastoid) to 5 ms......-wave, facilitation still occurred at ISIs of -6 and -5 ms and depression of the paired response at ISIs of 0, 1, 4 and 5 ms. The interaction of the response to transmastoid stimulation with the multiple descending volleys elicited by magnetic stimulation of the cortex is complex. However, depression of the response...

  18. Mechanisms of osteocyte stimulation in osteoporosis.

    Science.gov (United States)

    Verbruggen, Stefaan W; Vaughan, Ted J; McNamara, Laoise M

    2016-09-01

    Experimental studies have shown that primary osteoporosis caused by oestrogen-deficiency results in localised alterations in bone tissue properties and mineral composition. Additionally, changes to the lacunar-canalicular architecture surrounding the mechanosensitive osteocyte have been observed in animal models of the disease. Recently, it has also been demonstrated that the mechanical stimulation sensed by osteocytes changes significantly during osteoporosis. Specifically, it was shown that osteoporotic bone cells experience higher maximum strains than healthy bone cells after short durations of oestrogen deficiency. However, in long-term oestrogen deficiency there was no significant difference between bone cells in healthy and normal bone. The mechanisms by which these changes arise are unknown. In this study, we test the hypothesis that complex changes in tissue composition and lacunar-canalicular architecture during osteoporosis alter the mechanical stimulation of the osteocyte. The objective of this research is to employ computational methods to investigate the relationship between changes in bone tissue composition and microstructure and the mechanical stimulation of osteocytes during osteoporosis. By simulating physiological loading, it was observed that an initial decrease in tissue stiffness (of 0.425GPa) and mineral content (of 0.66wt% Ca) relative to controls could explain the mechanical stimulation observed at the early stages of oestrogen deficiency (5 weeks post-OVX) during in situ bone cell loading in an oestrogen-deficient rat model of post-menopausal osteoporosis (Verbruggen et al., 2015). Moreover, it was found that a later increase in stiffness (of 1.175GPa) and mineral content (of 1.64wt% Ca) during long-term osteoporosis (34 weeks post-OVX), could explain the mechanical stimuli previously observed at a later time point due to the progression of osteoporosis. Furthermore, changes in canalicular tortuosity arising during osteoporosis were shown

  19. Monitoring changes in hemodynamics following optogenetic stimulation

    Science.gov (United States)

    Frye, Seth

    The brain is composed of billions of neurons, all of which connected through a vast network. After years of study and applications of different technologies and techniques, there are still more questions than answers when it comes to the fundamental functions of the brain. This project aims to provide a new tool which can be used to gain a better understanding of the fundamental mechanisms that govern neurological processes inside the brain. In order for neural networks to operate, blood has to be supplied through neighboring blood vessels. As such, the increase or decrease in the blood supply has been used as an indicator of neural activity. The neural activity and blood supply relationship is known as neural vasculature coupling. Monitoring the hemodynamics is used as an indicator of neurological activity, but the causal relationship is an area of current research. Gaining a better understanding of the coupling of neural activity and the surrounding vasculature provides a more accurate methodology to evaluate regional neural activity. The new optical technology applied in this project provides a set of tools to both stimulate and monitor this coupling relationship. Optogenetics provides the capability of stimulating neural activity using specific wavelengths of light. Essentially this tool allows for the direct stimulation of networks of neurons by simply shining one color of light onto the brain. Optical Coherence Tomography (OCT), another new optical technology applied in this project, can record volumetric images of blood vessels and flow using only infrared light. The combination of the two optical technologies is then capable of stimulating neural activity and monitoring the hemodynamic response inside the brain using only light. As a result of this project we have successfully demonstrated the capability of both stimulating and imaging the brain using new optical technologies. The optical stimulation of neural activity has evoked a direct hemodynamic effect

  20. Transcranial Alternating Current Stimulation (tACS) Enhances Mental Rotation Performance during and after Stimulation

    Science.gov (United States)

    Kasten, Florian H.; Herrmann, Christoph S.

    2017-01-01

    Transcranial alternating current stimulation (tACS) has been repeatedly demonstrated to modulate endogenous brain oscillations in a frequency specific manner. Thus, it is a promising tool to uncover causal relationships between brain oscillations and behavior or perception. While tACS has been shown to elicit a physiological aftereffect for up to 70 min, it remains unclear whether the effect can still be elicited if subjects perform a complex task interacting with the stimulated frequency band. In addition, it has not yet been investigated whether the aftereffect is behaviorally relevant. In the current experiment, participants performed a Shepard-like mental rotation task for 80 min. After 10 min of baseline measurement, participants received either 20 min of tACS at their individual alpha frequency (IAF) or sham stimulation (30 s tACS in the beginning of the stimulation period). Afterwards another 50 min of post-stimulation EEG were recorded. Task performance and EEG were acquired during the whole experiment. While there were no effects of tACS on reaction times or event-related-potentials (ERPs), results revealed an increase in mental rotation performance in the stimulation group as compared to sham both during and after stimulation. This was accompanied by increased ongoing alpha power and coherence as well as event-related-desynchronization (ERD) in the alpha band in the stimulation group. The current study demonstrates a behavioral and physiological aftereffect of tACS in parallel. This indicates that it is possible to elicit aftereffects of tACS during tasks interacting with the alpha band. Therefore, the tACS aftereffect is suitable to achieve an experimental manipulation. PMID:28197084

  1. Multifocal visual evoked responses to dichoptic stimulation using virtual reality goggles: Multifocal VER to dichoptic stimulation.

    Science.gov (United States)

    Arvind, Hemamalini; Klistorner, Alexander; Graham, Stuart L; Grigg, John R

    2006-05-01

    Multifocal visual evoked potentials (mfVEPs) have demonstrated good diagnostic capabilities in glaucoma and optic neuritis. This study aimed at evaluating the possibility of simultaneously recording mfVEP for both eyes with dichoptic stimulation using virtual reality goggles and also to determine the stimulus characteristics that yield maximum amplitude. ten healthy volunteers were recruited and temporally sparse pattern pulse stimuli were presented dichoptically using virtual reality goggles. Experiment 1 involved recording responses to dichoptically presented checkerboard stimuli and also confirming true topographic representation by switching off specific segments. Experiment 2 involved monocular stimulation and comparison of amplitude with Experiment 1. In Experiment 3, orthogonally oriented gratings were dichoptically presented. Experiment 4 involved dichoptic presentation of checkerboard stimuli at different levels of sparseness (5.0 times/s, 2.5 times/s, 1.66 times/s and 1.25 times/s), where stimulation of corresponding segments of two eyes were separated by 16.7, 66.7,116.7 & 166.7 ms respectively. Experiment 1 demonstrated good traces in all regions and confirmed topographic representation. However, there was suppression of amplitude of responses to dichoptic stimulation by 17.9+/-5.4% compared to monocular stimulation. Experiment 3 demonstrated similar suppression between orthogonal and checkerboard stimuli (p = 0.08). Experiment 4 demonstrated maximum amplitude and least suppression (4.8%) with stimulation at 1.25 times/s with 166.7 ms separation between eyes. It is possible to record mfVEP for both eyes during dichoptic stimulation using virtual reality goggles, which present binocular simultaneous patterns driven by independent sequences. Interocular suppression can be almost eliminated by using a temporally sparse stimulus of 1.25 times/s with a separation of 166.7 ms between stimulation of corresponding segments of the two eyes.

  2. Non-invasive brain stimulation in early rehabilitation after stroke.

    Science.gov (United States)

    Blesneag, A V; Popa, L; Stan, A D

    2015-01-01

    The new tendency in rehabilitation involves non-invasive tools that, if applied early after stroke, promote neurorecovery. Repetitive transcranial magnetic stimulation and transcranial direct current stimulation may correct the disruption of cortical excitability and effectively contribute to the restoration of movement and speech. The present paper analyses the results of non-invasive brain stimulation (NIBS) trials, highlighting different aspects related to the repetitive transcranial magnetic stimulation frequency, transcranial direct current stimulation polarity, the period and stimulation places in acute and subacute ischemic strokes. The risk of adverse events, the association with motor or language recovery specific training, and the cumulative positive effect evaluation are also discussed.

  3. On the possible role of stimulation duration for after-effects of transcranial alternating current stimulation

    Directory of Open Access Journals (Sweden)

    Daniel eStrüber

    2015-08-01

    Full Text Available Transcranial alternating current stimulation is a novel method that allows application of sinusoidal currents to modulate brain oscillations and cognitive processes. Studies in humans have demonstrated tACS after-effects following stimulation durations in the range of minutes. However, such after-effects are absent in animal studies using much shorter stimulation protocols in the range of seconds. Thus, stimulation duration might be a critical parameter for after-effects to occur. To test this hypothesis, we repeated a recent human tACS experiment with a short duration. We applied alpha tACS intermittently for one second duration while keeping other parameters identical. The results demonstrate that this very short intermittent protocol did not produce after-effects on amplitude or phase of the electroencephalogram. Since synaptic plasticity has been suggested as a possible mechanism for after-effects, our results indicate that a stimulation duration of one second is too short to induce synaptic plasticity. Future studies in animals are required that use extended stimulation durations to reveal the neuronal underpinnings. A better understanding of the mechanisms of tACS after-effects is crucial for potential clinical applications.

  4. Amplifier design for EMG recording from stimulation electrodes during functional electrical stimulation leg cycling ergometry.

    Science.gov (United States)

    Shalaby, Raafat; Schauer, Thomas; Liedecke, Wolfgang; Raisch, Jörg

    2011-02-01

    Functional electrical stimulation leg cycle ergometry (FES-LCE), which is often used as exercise for people with spinal cord injury (SCI), has recently been applied in the motor rehabilitation of stroke patients. Recently completed studies show controversial results, but with a tendency to positive training effects. Current technology is identical to that used in FES-LCE for SCI, whereas the pathology of stroke differs strongly. Most stroke patients with hemiparesis are able to drive an ergometer independently. Depending on the degree of spasticity, the paretic leg will partially support or hinder movements. Electrical stimulation increases muscle force and endurance and both are prerequisites for restoring gait. However, the effect of FES-LCE on improving impaired motor coordination is unclear. To measure motor coordination during FES-LCE, an EMG-amplifier design has been investigated which suppresses stimulation artifacts and allows detection of volitional or reflex induced muscle activity. Direct measurement of EMG from stimulation electrodes between stimulation pulses is an important asset of this amplifier. Photo-MOS switches in front of the preamplifier are utilized to achieve this. The technology presented here can be used to monitor the effects of FES-LCE to adapt the stimulation strategy or to realize EMG-biofeedback training.

  5. Post-stimulation block of frog sciatic nerve by high-frequency (kHz) biphasic stimulation.

    Science.gov (United States)

    Yang, Guangning; Xiao, Zhiying; Wang, Jicheng; Shen, Bing; Roppolo, James R; de Groat, William C; Tai, Changfeng

    2017-04-01

    This study determined if high-frequency biphasic stimulation can induce nerve conduction block that persists after the stimulation is terminated, i.e., post-stimulation block. The frog sciatic nerve-muscle preparation was used in the study. Muscle contraction force induced by low-frequency (0.5 Hz) nerve stimulation was recorded to indicate the occurrence and recovery of nerve block induced by the high-frequency (5 or 10 kHz) biphasic stimulation. Nerve block was observed during high-frequency stimulation and after termination of the stimulation. The recovery from post-stimulation block occurred in two distinct phases. During the first phase, the complete block induced during high-frequency stimulation was maintained. The average maximal duration for the first phase was 107 ± 50 s. During the second phase, the block gradually or abruptly reversed. The duration of both first and second phases was dependent on stimulation intensity and duration but not frequency. Stimulation of higher intensity (1.4-2 times block threshold) and longer duration (5 min) produced the longest period (249 ± 58 s) for a complete recovery. Post-stimulation block can be induced by high-frequency biphasic stimulation, which is important for future investigations of the blocking mechanisms and for optimizing the stimulation parameters or protocols in clinical applications.

  6. Optically stimulated luminescence dating of rock surfaces

    DEFF Research Database (Denmark)

    Sohbati, Reza

    There are many examples of rock surfaces, rock art and stone structures whose ages are of great importance to the understanding of various phenomena in geology, climatology and archaeology. Optically stimulated luminescence (OSL) dating is a well-established chronological tool that has successfully...... of rock surfaces is successfully tested by application to two different quartz-rich rock types (sandstone and quartzite). Together with the measurement of infrared stimulated luminescence (IRSL) signals as a function of depth into the surface of different granites it is clear that both OSL and IRSL can....... Based on the studies of residual luminescence as a function of depth into a rock surface discussed above, a model is developed that relates this increase in residual luminescence to the exposure time. The model is then further developed using the quartz OSL signal from buried quartzite cobbles...

  7. Stimulated recall interviews for describing pragmatic epistemology

    Science.gov (United States)

    Shubert, Christopher W.; Meredith, Dawn C.

    2015-12-01

    Students' epistemologies affect how and what they learn: do they believe physics is a list of equations, or a coherent and sensible description of the physical world? In order to study these epistemologies as part of curricular assessment, we adopt the resources framework, which posits that students have many productive epistemological resources that can be brought to bear as they learn physics. In previous studies, these epistemologies have been either inferred from behavior in learning contexts or probed through surveys or interviews outside of the learning context. We argue that stimulated recall interviews provide a contextually and interpretively valid method to access students' epistemologies that complement existing methods. We develop a stimulated recall interview methodology to assess a curricular intervention and find evidence that epistemological resources aptly describe student epistemologies.

  8. [Deep brain stimulation for hyperkinetic movement disorders].

    Science.gov (United States)

    Reich, M M; Volkmann, J

    2014-02-01

    The term hyperkinetic movement disorder encompasses dystonia, tremor, chorea, myoclon and tics. These symptoms are all caused by dysfunctional neural networks including the basal ganglia loop and can be accompanied by other neurological or psychiatric symptoms. Deep brain stimulation (DBS) is an important extension of therapeutic options for this group of patients in whom drug therapy is limited. Permanent electrodes are implanted in various subcortical brain areas in order to achieve an improvement in motor symptoms by high frequency stimulation. Already established indications include primary generalized or segmental dystonia and essential tremor but an increasingly better understanding of systemic pathophysiology has allowed DBS to be explored as a treatment for other disorders of the hyperkinetic spectrum. This article provides an overview of common hyperkinetic movement disorders from the viewpoint of recent advances in neurostimulation therapy.

  9. Optically stimulated luminescence dating of rock surfaces

    DEFF Research Database (Denmark)

    Sohbati, Reza

    There are many examples of rock surfaces, rock art and stone structures whose ages are of great importance to the understanding of various phenomena in geology, climatology and archaeology. Optically stimulated luminescence (OSL) dating is a well-established chronological tool that has successfully...... determined the depositional age of a wide variety of fine-grained sediments, from several years to several hundred thousands of years. However, there is no routine OSL dating method applicable to larger clasts such as cobbles, boulders and other rock surfaces. Here the application of quartz OSL to the dating...... of rock surfaces is successfully tested by application to two different quartz-rich rock types (sandstone and quartzite). Together with the measurement of infrared stimulated luminescence (IRSL) signals as a function of depth into the surface of different granites it is clear that both OSL and IRSL can...

  10. PRESYNAPTIC DOPAMINE MODULATION BY STIMULANT SELF ADMINISTRATION

    Science.gov (United States)

    España, Rodrigo A.; Jones, Sara R.

    2013-01-01

    The mesolimbic dopamine system is an essential participant in the initiation and modulation of various forms of goal-directed behavior, including drug reinforcement and addiction processes. Dopamine neurotransmission is increased by acute administration of all drugs of abuse, including the stimulants cocaine and amphetamine. Chronic exposure to these drugs via voluntary self-administration provides a model of stimulant abuse that is useful in evaluating potential behavioral and neurochemical adaptations that occur during addiction. This review describes commonly used methodologies to measure dopamine and baseline parameters of presynaptic dopamine regulation, including exocytotic release and reuptake through the dopamine transporter in the nucleus accumbens core, as well as dramatic adaptations in dopamine neurotransmission and drug sensitivity that occur with acute non-contingent and chronic, contingent self-administration of cocaine and amphetamine. PMID:23277050

  11. Enhancement stimulants: perceived motivational and cognitive advantages

    Directory of Open Access Journals (Sweden)

    Irena P. Ilieva

    2013-10-01

    Full Text Available Psychostimulants like Adderall and Ritalin are widely used for cognitive enhancement by people without ADHD, although the empirical literature has shown little conclusive evidence for effectiveness in this population. This paper explores one potential explanation of this discrepancy: the possibility that the benefit from enhancement stimulants is at least in part motivational, rather than purely cognitive. We review relevant laboratory, survey and interview research and present the results of a new survey of enhancement users with the goal of comparing perceived cognitive and motivational effects. These users perceived stimulant effects on motivationally-related factors, especially energy and motivation, and reported motivational effects to be at least as pronounced as cognitive effects, including effects on "attention."

  12. The transition process: Stimulating free entrepreneurship

    Directory of Open Access Journals (Sweden)

    Stojanović Božo J.

    2003-01-01

    Full Text Available The text consists of two parts. In the first we expound the thesis that transition is actually a process of creation of institutional preconditions for development of private entrepreneurship at a given moment and under the inherited circumstances. To create an environment that stimulates free entrepreneurship and enables a successful transition requires a lot of knowledge, creativity and pragmatism (there is no general model. The rest remains on the entrepreneurs. In the second part we analyse the experience of FRY before and after the change of regime. During the former regime FRY was an example of degenerative connection between politics and economy geared to prevent reforms. The task of the new government is to make a radical break with the earlier practice. If the reform is not radical and not aiming to create an institutional environment that fully stimulates competition and private entrepreneurship (which has not been the case so far, it has no good prospects to succeed.

  13. Image formation using stimulated raman scattering gain

    Science.gov (United States)

    Bespalov, V. G.; Makarov, E. A.; Stasel'ko, D. I.

    2016-07-01

    Theoretical analysis of the spatial, noise, and energy characteristics of an amplifier has been performed in the mode of spectral and time selection using subnanosecond stimulated Raman Scattering gain of weak echo signals in crystalline active media that are known for high (up to 10-1 cm/MW) gain coefficients. The possibility to reach high gain values has been demonstrated for weak signals from objects at acceptable angular sizes of the field of vision of an amplifier. To provide a signal-to-noise ratio that exceeds unity over the entire field of vision, the number of photons at the input to an amplifier that is required has to exceed the number of its resolution elements. Accurate determination of the possibilities of recording of weak echo signals and quality of images of targets that are obtained using amplifiers under stimulated Raman Scattering requires additional special experiments.

  14. Spinal cord stimulation: Background and clinical application

    DEFF Research Database (Denmark)

    Meier, Kaare

    2014-01-01

    Background Spinal cord stimulation (SCS) is a surgical treatment for chronic neuropathic pain refractory to conventional treatment. SCS treatment consists of one or more leads implanted in the epidural space of the spinal canal, connected to an implantable pulse generator (IPG). Each lead carries...... is described in detail and illustrated with a series of intraoperative pictures. Finally, indications for SCS are discussed along with some of the controversies surrounding the therapy. Implications The reader is presented with a broad overview of spinal cord stimulation, including the historical...... a number of contacts capable of delivering a weak electrical current to the spinal cord, evoking a feeling of peripheral paresthesia. With correct indication and if implanted by an experienced implanter, success rates generally are in the range of about 50–75%. Common indications include complex regional...

  15. Universal signal generator for dynamic cell stimulation.

    Science.gov (United States)

    Piehler, Andreas; Ghorashian, Navid; Zhang, Ce; Tay, Savaş

    2017-06-27

    Dynamic cell stimulation is a powerful technique for probing gene networks and for applications in stem cell differentiation, immunomodulation and signaling. We developed a robust and flexible method and associated microfluidic devices to generate a wide-range of precisely formulated dynamic chemical signals to stimulate live cells and measure their dynamic response. This signal generator is capable of digital to analog conversion (DAC) through combinatoric selection of discrete input concentrations, and outperforms existing methods by both achievable resolution, dynamic range and simplicity in design. It requires no calibration, has minimal space requirements and can be easily integrated into microfluidic cell culture devices. The signal generator hardware and software we developed allows to choose the waveform, period and amplitude of chemical input signals and features addition of well-defined chemical noise to study the role of stochasticity in cellular information processing.

  16. Plasmonic nanoprobes for stimulated emission depletion microscopy

    CERN Document Server

    Cortes, Emiliano; Sinclair, Hugo G; Guldbrand, Stina; Peveler, William J; Davies, Timothy; Parrinello, Simona; Görlitz, Frederik; Dunsby, Chris; Neil, Mark A A; Sivan, Yonatan; Parkin, Ivan P; French, Paul M; Maier, Stefan A

    2016-01-01

    Plasmonic nanoparticles influence the absorption and emission processes of nearby emitters due to local enhancements of the illuminating radiation and the photonic density of states. Here, we use the plasmon resonance of metal nanoparticles in order to enhance the stimulated depletion of excited molecules for super-resolved microscopy. We demonstrate stimulated emission depletion (STED) microscopy with gold nanorods with a long axis of only 26 nm and a width of 8 nm that provide an enhancement of the resolution compared to fluorescent-only probes without plasmonic components irradiated with the same depletion power. These novel nanoparticle-assisted STED probes represent a ~2x10^3 reduction in probe volume compared to previously used nanoparticles and we demonstrate their application to the first plasmon-assisted STED cellular imaging. We also discuss their current limitations.

  17. Where does TMS Stimulate the Motor Cortex?

    DEFF Research Database (Denmark)

    Bungert, Andreas; Antunes, André; Espenhahn, Svenja;

    2016-01-01

    Much of our knowledge on the physiological mechanisms of transcranial magnetic stimulation (TMS) stems from studies which targeted the human motor cortex. However, it is still unclear which part of the motor cortex is predominantly affected by TMS. Considering that the motor cortex consists...... of functionally and histologically distinct subareas, this also renders the hypotheses on the physiological TMS effects uncertain. We use the finite element method (FEM) and magnetic resonance image-based individual head models to get realistic estimates of the electric field induced by TMS. The field changes...... in different subparts of the motor cortex are compared with electrophysiological threshold changes of 2 hand muscles when systematically varying the coil orientation in measurements. We demonstrate that TMS stimulates the region around the gyral crown and that the maximal electric field strength in this region...

  18. Anesthesia for Pediatric Deep Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Joseph Sebeo

    2010-01-01

    Full Text Available In patients refractory to medical therapy, deep brain stimulations (DBSs have emerged as the treatment of movement disorders particularly Parkinson's disease. Their use has also been extended in pediatric and adult patients to treat epileptogenic foci. We here performed a retrospective chart review of anesthesia records from 28 pediatric cases of patients who underwent DBS implantation for dystonia using combinations of dexmedetomidine and propofol-based anesthesia. Complications with anesthetic techniques including airway and cardiovascular difficulties were analyzed.

  19. Bubble nonlinear dynamics and stimulated scattering process

    Science.gov (United States)

    Jie, Shi; De-Sen, Yang; Sheng-Guo, Shi; Bo, Hu; Hao-Yang, Zhang; Shi-Yong, Hu

    2016-02-01

    A complete understanding of the bubble dynamics is deemed necessary in order to achieve their full potential applications in industry and medicine. For this purpose it is first needed to expand our knowledge of a single bubble behavior under different possible conditions including the frequency and pressure variations of the sound field. In addition, stimulated scattering of sound on a bubble is a special effect in sound field, and its characteristics are associated with bubble oscillation mode. A bubble in liquid can be considered as a representative example of nonlinear dynamical system theory with its resonance, and its dynamics characteristics can be described by the Keller-Miksis equation. The nonlinear dynamics of an acoustically excited gas bubble in water is investigated by using theoretical and numerical analysis methods. Our results show its strongly nonlinear behavior with respect to the pressure amplitude and excitation frequency as the control parameters, and give an intuitive insight into stimulated sound scattering on a bubble. It is seen that the stimulated sound scattering is different from common dynamical behaviors, such as bifurcation and chaos, which is the result of the nonlinear resonance of a bubble under the excitation of a high amplitude acoustic sound wave essentially. The numerical analysis results show that the threshold of stimulated sound scattering is smaller than those of bifurcation and chaos in the common condition. Project supported by the Program for Changjiang Scholars and Innovative Research Team in University, China (Grant No. IRT1228) and the Young Scientists Fund of the National Natural Science Foundation of China (Grant Nos. 11204050 and 11204049).

  20. Stimulated emission from donor transitions in silicon

    Science.gov (United States)

    Pavlov; Zhukavin; Orlova; Shastin; Kirsanov; Hubers; Auen; Riemann

    2000-05-29

    The observation of far-infrared stimulated emission from shallow donor transitions in silicon is reported. Lasing with a wavelength of 59 &mgr;m due to the neutral donor intracenter 2p(0)-->1s(E) transition in Si:P pumped by CO2 laser radiation is obtained. Populations of D0 and D- center states and the balance of the radiation absorption and amplification are theoretically analyzed.

  1. Thermally stimulated luminescence of urine salts

    Science.gov (United States)

    Bordun, O.; Drobchak, O.

    2008-05-01

    The thermally stimulated luminescence (TSL) of normal and pathological urine was studied. The presence of pathological salts leads to extinguishing of TSL intensity and to the appearance of additional stripes with maxima nearly 118 and 205K, except of characteristic stripes with the maxima nearly 173 and 260K. TSL stripes depend on urine constituents. The comparison of TSL intensity of normal and pathological urine is carried out and energies of thermal activation are determined for most intensive TSL stripes.

  2. Laser-Stimulated Fluorescence in Paleontology

    OpenAIRE

    Kaye, Thomas G.; Falk, Amanda R.; Michael Pittman; Sereno, Paul C.; Martin, Larry D.; Burnham, David A.; Enpu Gong; Xing Xu; Yinan Wang

    2015-01-01

    Fluorescence using ultraviolet (UV) light has seen increased use as a tool in paleontology over the last decade. Laser-stimulated fluorescence (LSF) is a next generation technique that is emerging as a way to fluoresce paleontological specimens that remain dark under typical UV. A laser's ability to concentrate very high flux rates both at the macroscopic and microscopic levels results in specimens fluorescing in ways a standard UV bulb cannot induce. Presented here are five paleontological c...

  3. Managing Parkinson's disease with continuous dopaminergic stimulation.

    Science.gov (United States)

    Wolters, Erik; Lees, Andrew J; Volkmann, Jens; van Laar, Teus; Hovestadt, Ad

    2008-04-01

    The pathophysiology of Parkinson's disease is marked by the loss of dopaminergic neurons, which leads to striatal dopaminergic deficiency. This causes resting tremor, hypokinesia, rigidity, bradykinesia, and loss of postural reflexes. Most current treatments for Parkinson's disease aim to restore striatal dopamine signaling by increasing the supply of dopamine with oral levodopa (L-dopa), stimulating dopamine receptors directly using dopamine agonists, or inhibiting the reuptake of endogenous dopamine. L-dopa is standard therapy for patients with Parkinson's disease. However, with continued treatment and disease progression, the response to oral dopaminergic drugs becomes unstable and motor fluctuations emerge, including off periods and dyskinesia. Direct duodenal-administered infusible L-dopa/carbidopa is effective for the management of refractory motor fluctuations in some patient populations. However, enteral infusions cannot mimic the function of the normal dopaminergic brain, and around-the-clock constant-rate administration carries the risk of causing refractory off periods associated with severe immobility and hyperpyrexia. Subthalamic nucleus (STN) deep brain stimulation (DBS) is also a promising treatment. DBS passes a high-frequency electrical current into the target area, mimicking the effect of lesioning the stimulated area. However, this treatment requires invasive surgery and is appropriate for a limited segment of the patient population. This supplement provides a rationale for the use of continuous dopaminergic receptor stimulation and offers guidelines on the individualization of treatment decisions, with special focus on continuous L-dopa infusion and STN DBS. Erik Wolters, MD, PhD, offers an introduction to the impact of continuous L-dopa infusion. Andrew J. Lees, MD, FRCP, provides an overview of the physiologic response to L-dopa and reviews clinical pharmacologic studies of intravenous and intraduodenal L-dopa. Jens Volkmann, MD, discusses

  4. Tactile stimulation can suppress visual perception

    OpenAIRE

    Masakazu Ide; Souta Hidaka

    2013-01-01

    An input (e.g., airplane takeoff sound) to a sensory modality can suppress the percept of another input (e.g., talking voices of neighbors) of the same modality. This perceptual suppression effect is evidence that neural responses to different inputs closely interact with each other in the brain. While recent studies suggest that close interactions also occur across sensory modalities, crossmodal perceptual suppression effect has not yet been reported. Here, we demonstrate that tactile stimul...

  5. Single-pulse stimulated Raman scattering spectroscopy

    CERN Document Server

    Frostig, Hadas; Natan, Adi; Silberberg, Yaron

    2010-01-01

    We demonstrate the acquisition of stimulated Raman scattering spectra with the use of a single femtosecond pulse. High resolution vibrational spectra are obtained by shifting the phase of a narrow band of frequencies in the broadband input pulse spectrum, using spectral shaping. The vibrational spectrum is resolved by examining the amplitude features formed in the spectrum after interaction with the sample. Using this technique, low frequency Raman lines (<100cm^-1) are resolved in a straightforward manner.

  6. Deep Brain Stimulation og Identitet i Fremtiden

    OpenAIRE

    Andersen, Camilla; Farah, Adna; Pil, Kierkegaard; Lucas, Haasum

    2015-01-01

    The rapidly progressing technology of today is the impetus for increased interest and discussion regarding transhumanism. As a result, our group has decided to conduct research regarding deep brain stimulation, in order to focus on a single technology that is growing rapidly and seeing multiple uses in treating various neurological pathologies. The possibilities of the technology will be relevant to the future of transhuman though, as well as the immediate effects on the individuals who elec...

  7. Reducing interaction in simultaneous paired stimulation with CI

    Science.gov (United States)

    Vellinga, Dirk; Briaire, Jeroen J.; Kalkman, Randy K.; Frijns, Johan H. M.

    2017-01-01

    In this study simultaneous paired stimulation of electrodes in cochlear implants is investigated by psychophysical experiments in 8 post-lingually deaf subjects (and one extra subject who only participated in part of the experiments). Simultaneous and sequential monopolar stimulation modes are used as references and are compared to channel interaction compensation, partial tripolar stimulation and a novel sequential stimulation strategy named phased array compensation. Psychophysical experiments are performed to investigate both the loudness integration during paired stimulation at the main electrodes as well as the interaction with the electrode contact located halfway between the stimulating pair. The study shows that simultaneous monopolar stimulation has more loudness integration on the main electrodes and more interaction in between the electrodes than sequential stimulation. Channel interaction compensation works to reduce the loudness integration at the main electrodes, but does not reduce the interaction in between the electrodes caused by paired stimulation. Partial tripolar stimulation uses much more current to reach the needed loudness, but shows the same interaction in between the electrodes as sequential monopolar stimulation. In phased array compensation we have used the individual impedance matrix of each subject to calculate the current needed on each electrode to exactly match the stimulation voltage along the array to that of sequential stimulation. The results show that the interaction in between the electrodes is the same as monopolar stimulation. The strategy uses less current than partial tripolar stimulation, but more than monopolar stimulation. In conclusion, the paper shows that paired stimulation is possible if the interaction is compensated. PMID:28182685

  8. Locating a leaking crack by safe stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, C.E.; Sagat, S. (Atomic Energy of Canada Ltd., Chalk River, ON (Canada). Chalk River Nuclear Labs.); Shek, G.K.; Graham, D.B.; Durand, M.A. (Ontario Hydro, Toronto, ON (Canada))

    1990-01-01

    A few Zr-2.5 Nb alloy pressure tubes in CANDU nuclear reactors have leaked through cracks that have grown by delayed hydride cracking (DHC). In some instances, tubes contained confirmed leaks that were leaking at a rate too low for precise identification of the leaking channel. Controlled stimulation of DHC can be used to help locate these leaks by extending the crack and increasing the leak rate without approaching crack instability. In the event of a leak being detected, a plant operator can gain time for leak location by a heating and unloading manoeuvre that will arrest crack growth and increase the critical crack length. This manoeuvre increases the safety margin against tube rupture. If required, the operator can then stimulate cracking in a controlled manner to aid in leak identification. Sequences of temperature and load manoeuvres for safe crack stimulation have been found by laboratory tests on dry specimens and the efficacy of the process has been demonstrated, partly in a power reactor, and partly in a full-scale simulation of a leaking pressure tube. (author).

  9. Stimulation of ribosomal frameshifting by antisense LNA

    Science.gov (United States)

    Yu, Chien-Hung; Noteborn, Mathieu H. M.; Olsthoorn, René C. L.

    2010-01-01

    Programmed ribosomal frameshifting is a translational recoding mechanism commonly used by RNA viruses to express two or more proteins from a single mRNA at a fixed ratio. An essential element in this process is the presence of an RNA secondary structure, such as a pseudoknot or a hairpin, located downstream of the slippery sequence. Here, we have tested the efficiency of RNA oligonucleotides annealing downstream of the slippery sequence to induce frameshifting in vitro. Maximal frameshifting was observed with oligonucleotides of 12–18 nt. Antisense oligonucleotides bearing locked nucleid acid (LNA) modifications also proved to be efficient frameshift-stimulators in contrast to DNA oligonucleotides. The number, sequence and location of LNA bases in an otherwise DNA oligonucleotide have to be carefully manipulated to obtain optimal levels of frameshifting. Our data favor a model in which RNA stability at the entrance of the ribosomal tunnel is the major determinant of stimulating slippage rather than a specific three-dimensional structure of the stimulating RNA element. PMID:20693527

  10. Herbicide phosphinothricin causes direct stimulation hormesis.

    Science.gov (United States)

    Dragićević, Milan; Platiša, Jelena; Nikolić, Radomirka; Todorović, Slađana; Bogdanović, Milica; Mitić, Nevena; Simonović, Ana

    2012-01-01

    Herbicide phosphinothricin (PPT) inhibits glutamine synthetase (GS), a key enzyme in nitrogen assimilation, thus causing ammonia accumulation, glutamine depletion and eventually plant death. However, the growth response of Lotus corniculatus L. plants immersed in solutions with a broad range of PPT concentrations is biphasic, with pronounced stimulating effect on biomass production at concentrations ≤ 50 μM and growth inhibition at higher concentrations. The growth stimulation at low PPT concentrations is a result of activation of chloroplastic isoform GS2, while the growth suppression is caused by inhibition of both cytosolic GS1 and GS2 at higher PPT concentrations. Since the results are obtained in cell-free system (e.g. protein extracts), to which the principles of homeostasis are not applicable, this PPT effect is an unambiguous example of direct stimulation hormesis. A detailed molecular mechanism of concentration-dependent interaction of both PPT and a related GS inhibitor, methionine sulfoximine, with GS holoenzymes is proposed. The mechanism is in concurrence with all experimental and literature data.

  11. Therapeutic Noninvasive Brain Stimulation in Alzheimer's Disease.

    Science.gov (United States)

    Gonsalvez, Irene; Baror, Roey; Fried, Peter; Santarnecchi, Emiliano; Pascual-Leone, Alvaro

    2017-01-01

    Alzheimer's disease (AD) is a looming public health crisis that currently lacks an effective treatment. Noninvasive Brain Stimulation (NBS), particularly transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), offers a promising alternative approach to pharmacological interventions for an increasing number of neurological and psychiatric conditions. The aim of this review is summarize data from therapeutic trials of NBS in AD and other dementing illnesses. Despite the potential of NBS, there is limited theoretical framework and a lack of guidelines for its applications to AD. Several published clinical trials failed to report key parameters of the interventions thus limiting the utility of the study to assess efficacy and safety. Our review concludes with some suggestions for future studies aimed to advance research into NBS as a potential treatment for the symptoms and disabilities caused by AD and to enable comparison of results across trials. Ultimately, appropriately powered, and controlled, multi-site randomized clinical trials will be needed to evaluate the therapeutic potential of NBS in AD.

  12. Transcranial magnetic stimulation after spinal cord injury.

    Science.gov (United States)

    Awad, Basem I; Carmody, Margaret A; Zhang, Xiaoming; Lin, Vernon W; Steinmetz, Michael P

    2015-02-01

    To review the basic principles and techniques of transcranial magnetic stimulation (TMS) and provide information and evidence regarding its applications in spinal cord injury clinical rehabilitation. A review of the available current and historical literature regarding TMS was conducted, and a discussion of its potential use in spinal cord injury rehabilitation is presented. TMS provides reliable information about the functional integrity and conduction properties of the corticospinal tracts and motor control in the diagnostic and prognostic assessment of various neurological disorders. It allows one to follow the evolution of motor control and to evaluate the effects of different therapeutic procedures. Motor-evoked potentials can be useful in follow-up evaluation of motor function during treatment and rehabilitation, specifically in patients with spinal cord injury and stroke. Although studies regarding somatomotor functional recovery after spinal cord injury have shown promise, more trials are required to provide strong and substantial evidence. TMS is a promising noninvasive tool for the treatment of spasticity, neuropathic pain, and somatomotor deficit after spinal cord injury. Further investigation is needed to demonstrate whether different protocols and applications of stimulation, as well as alternative cortical sites of stimulation, may induce more pronounced and beneficial clinical effects. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Newberry Volcano EGS Demonstration Stimulation Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Trenton T. Cladouhos, Matthew Clyne, Maisie Nichols,; Susan Petty, William L. Osborn, Laura Nofziger

    2011-10-23

    As a part of Phase I of the Newberry Volcano EGS Demonstration project, several data sets were collected to characterize the rock volume around the well. Fracture, fault, stress, and seismicity data has been collected by borehole televiewer, LiDAR elevation maps, and microseismic monitoring. Well logs and cuttings from the target well (NWG 55-29) and core from a nearby core hole (USGS N-2) have been analyzed to develop geothermal, geochemical, mineralogical and strength models of the rock matrix, altered zones, and fracture fillings (see Osborn et al., this volume). These characterization data sets provide inputs to models used to plan and predict EGS reservoir creation and productivity. One model used is AltaStim, a stochastic fracture and flow software model developed by AltaRock. The software's purpose is to model and visualize EGS stimulation scenarios and provide guidance for final planning. The process of creating an AltaStim model requires synthesis of geologic observations at the well, the modeled stress conditions, and the stimulation plan. Any geomechanical model of an EGS stimulation will require many assumptions and unknowns; thus, the model developed here should not be considered a definitive prediction, but a plausible outcome given reasonable assumptions. AltaStim is a tool for understanding the effect of known constraints, assumptions, and conceptual models on plausible outcomes.

  14. Andrographolide Stimulates Neurogenesis in the Adult Hippocampus

    Directory of Open Access Journals (Sweden)

    Lorena Varela-Nallar

    2015-01-01

    Full Text Available Andrographolide (ANDRO is a labdane diterpenoid component of Andrographis paniculata widely used for its anti-inflammatory properties. We have recently determined that ANDRO is a competitive inhibitor of glycogen synthase kinase-3β (GSK-3β, a key enzyme of the Wnt/β-catenin signaling cascade. Since this signaling pathway regulates neurogenesis in the adult hippocampus, we evaluated whether ANDRO stimulates this process. Treatment with ANDRO increased neural progenitor cell proliferation and the number of immature neurons in the hippocampus of 2- and 10-month-old mice compared to age-matched control mice. Moreover, ANDRO stimulated neurogenesis increasing the number of newborn dentate granule neurons. Also, the effect of ANDRO was evaluated in the APPswe/PS1ΔE9 transgenic mouse model of Alzheimer’s disease. In these mice, ANDRO increased cell proliferation and the density of immature neurons in the dentate gyrus. Concomitantly with the increase in neurogenesis, ANDRO induced the activation of the Wnt signaling pathway in the hippocampus of wild-type and APPswe/PS1ΔE9 mice determined by increased levels of β-catenin, the inactive form of GSK-3β, and NeuroD1, a Wnt target gene involved in neurogenesis. Our findings indicate that ANDRO stimulates neurogenesis in the adult hippocampus suggesting that this drug could be used as a therapy in diseases in which neurogenesis is affected.

  15. Andrographolide Stimulates Neurogenesis in the Adult Hippocampus.

    Science.gov (United States)

    Varela-Nallar, Lorena; Arredondo, Sebastian B; Tapia-Rojas, Cheril; Hancke, Juan; Inestrosa, Nibaldo C

    2015-01-01

    Andrographolide (ANDRO) is a labdane diterpenoid component of Andrographis paniculata widely used for its anti-inflammatory properties. We have recently determined that ANDRO is a competitive inhibitor of glycogen synthase kinase-3β (GSK-3β), a key enzyme of the Wnt/β-catenin signaling cascade. Since this signaling pathway regulates neurogenesis in the adult hippocampus, we evaluated whether ANDRO stimulates this process. Treatment with ANDRO increased neural progenitor cell proliferation and the number of immature neurons in the hippocampus of 2- and 10-month-old mice compared to age-matched control mice. Moreover, ANDRO stimulated neurogenesis increasing the number of newborn dentate granule neurons. Also, the effect of ANDRO was evaluated in the APPswe/PS1ΔE9 transgenic mouse model of Alzheimer's disease. In these mice, ANDRO increased cell proliferation and the density of immature neurons in the dentate gyrus. Concomitantly with the increase in neurogenesis, ANDRO induced the activation of the Wnt signaling pathway in the hippocampus of wild-type and APPswe/PS1ΔE9 mice determined by increased levels of β-catenin, the inactive form of GSK-3β, and NeuroD1, a Wnt target gene involved in neurogenesis. Our findings indicate that ANDRO stimulates neurogenesis in the adult hippocampus suggesting that this drug could be used as a therapy in diseases in which neurogenesis is affected.

  16. Andrographolide Stimulates Neurogenesis in the Adult Hippocampus

    Science.gov (United States)

    Varela-Nallar, Lorena; Arredondo, Sebastian B.; Tapia-Rojas, Cheril; Hancke, Juan; Inestrosa, Nibaldo C.

    2015-01-01

    Andrographolide (ANDRO) is a labdane diterpenoid component of Andrographis paniculata widely used for its anti-inflammatory properties. We have recently determined that ANDRO is a competitive inhibitor of glycogen synthase kinase-3β (GSK-3β), a key enzyme of the Wnt/β-catenin signaling cascade. Since this signaling pathway regulates neurogenesis in the adult hippocampus, we evaluated whether ANDRO stimulates this process. Treatment with ANDRO increased neural progenitor cell proliferation and the number of immature neurons in the hippocampus of 2- and 10-month-old mice compared to age-matched control mice. Moreover, ANDRO stimulated neurogenesis increasing the number of newborn dentate granule neurons. Also, the effect of ANDRO was evaluated in the APPswe/PS1ΔE9 transgenic mouse model of Alzheimer's disease. In these mice, ANDRO increased cell proliferation and the density of immature neurons in the dentate gyrus. Concomitantly with the increase in neurogenesis, ANDRO induced the activation of the Wnt signaling pathway in the hippocampus of wild-type and APPswe/PS1ΔE9 mice determined by increased levels of β-catenin, the inactive form of GSK-3β, and NeuroD1, a Wnt target gene involved in neurogenesis. Our findings indicate that ANDRO stimulates neurogenesis in the adult hippocampus suggesting that this drug could be used as a therapy in diseases in which neurogenesis is affected. PMID:26798521

  17. Physical properties of stimulated and unstimulated tears.

    Science.gov (United States)

    Pandit, J C; Nagyová, B; Bron, A J; Tiffany, J M

    1999-02-01

    It has long been assumed that unstimulated tears are more thoroughly equilibrated with epithelial secretions than stimulated tears, since they are in contact with tarsal, bulbar and corneal surfaces for longer. It was also believed from results with model solutions that soluble mucin is responsible for the observed surface tension and viscosity of tears. If longer contact means more mucin is dissolved in the aqueous tears, then the surface activity (surface tension lowered by mucin) and viscosity (raised by mucin) of tears should therefore be enhanced in unstimulated over stimulated tears. Pools of stimulated and minimally-stimulated tears were collected from a group of healthy adult volunteers by glass capillary. Viscosities were measured in the Contraves Low Shear 30 rheometer over the range of shear rates 0-130 sec-1. Surface tension was measured in the collection capillaries by a micro-technique, before and after refrigerated storage. Both surface tension and viscosity were determined for a variety of tear proteins and mucins. No significant difference was found between the viscosity/shear rate plots of stimulated and unstimulated tear samples. The viscosities of solutions of individual tear proteins were low, except for the combination of lysozyme and secretory IgA. Surface tensions were also similar in both cases, and unchanged by storage at room temperature or refrigeration, indicating no significant loss of surface-active material by adsorption on the capillary walls. Results with model mucin solutions gave a variety of results indicating either little surface activity or losses due to wall adsorption. Tear proteins, individually or in combination, did not lower surface tension to the level of tears. Tear viscosity seems not to depend on the level of dissolved mucins. This suggests either that a constant level of these is picked up even by short-term contact with ocular surfaces, or that viscosity arises from currently unknown materials which vary little

  18. Consecutive Acupuncture Stimulations Lead to Significantly Decreased Neural Responses

    NARCIS (Netherlands)

    Yeo, S.; Choe, I.H.; Noort, M.W.M.L. van den; Bosch, M.P.C.; Lim, S.

    2010-01-01

    Objective: Functional magnetic resonance imaging (fMRI), in combination with block design paradigms with consecutive acupuncture stimulations, has often been used to investigate the neural responses to acupuncture. In this study, we investigated whether previous acupuncture stimulations can affect

  19. Action-blindsight in healthy subjects after transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Christensen, Mark Schram; Kristiansen, Lasse; Rowe, James B.

    2008-01-01

    Clinical cases of blindsight have shown that visually guided movements can be accomplished without conscious visual perception. Here, we show that blindsight can be induced in healthy subjects by using transcranial magnetic stimulation over the visual cortex. Transcranial magnetic stimulation...

  20. Transcranial magnetic stimulation in the treatment of substance addiction

    National Research Council Canada - National Science Library

    Gorelick, David A; Zangen, Abraham; George, Mark S

    2014-01-01

    Transcranial magnetic stimulation (TMS) is a noninvasive method of brain stimulation used to treat a variety of neuropsychiatric disorders, but is still in the early stages of study as addiction treatment...

  1. Early Brain Stimulation May Help Stroke Survivors Recover Language Function

    Science.gov (United States)

    ... survivors with several types of aphasia at the rehabilitation hospital Rehanova and the Max-Planck-Institute for neurological research in Cologne, Germany. Thirteen received transcranial magnetic stimulation (TMS) and 11 got sham stimulation. The TMS ...

  2. Bioluminescence of Pleuromamma piseki under the effect of electric stimulation

    National Research Council Canada - National Science Library

    Yevstigneyev, P.V

    1983-01-01

    .... At the present time, the bioluminescence characteristics of numerous species are studied mostly with the use of electric stimulation which makes it possible to dose the stimulation more accurately...

  3. ADHD Common Among College Students Who Misuse Stimulant Drugs

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_160405.html ADHD Common Among College Students Who Misuse Stimulant Drugs ... misuse stimulant drugs are more likely to have attention-deficit hyperactivity disorder (ADHD) or other psychiatric problems, a new study ...

  4. Bimodal stimulation: benefits for music perception and sound quality.

    Science.gov (United States)

    Sucher, Catherine M; McDermott, Hugh J

    2009-01-01

    With recent expansions in cochlear implantation candidacy criteria, increasing numbers of implantees can exploit their remaining hearing by using bimodal stimulation (combining electrical stimulation via the implant with acoustic stimulation via hearing aids). This study examined the effect of bimodal stimulation on music perception and perceived sound quality. The perception of music and sound quality by nine post-lingually deafened adult implantees was examined in three conditions: implant alone, hearing aid alone and bimodal stimulation. On average, bimodal stimulation provided the best results for music perception and perceived sound quality when compared with results obtained with electrical stimulation alone. Thus, for implantees with usable acoustic hearing, bimodal stimulation may be advantageous when listening to music and other non-speech sounds.

  5. GUIDELINE Spinal cord stimulation for the management of pain ...

    African Journals Online (AJOL)

    trial of stimulation in FBSS, CRPS, and neuropathic pain. NICE concluded .... vascular disease), and others are emerging (e.g. visceral pain, interstitial cystitis) .... The same team should carry out trial stimulation and definitive implantation. 8.7.

  6. Functional Properties of Tooth Pulp Neurons Responding to Thermal Stimulation

    OpenAIRE

    Ahn, D.K.; Doutova, E.A.; McNaughton, K.; Light, A.R.; Närhi, M.; Maixner, W.

    2012-01-01

    The response properties of tooth pulp neurons that respond to noxious thermal stimulation of the dental pulp have been not well-studied. The present study was designed to characterize the response properties of tooth pulp neurons to noxious thermal stimulation of the dental pulp. Experiments were conducted on 25 male ferrets, and heat stimulation was applied by a computer-controlled thermode. Only 15% of tooth pulp neurons (n = 39) responded to noxious thermal stimulation of the teeth. Tooth ...

  7. Cardiac Autonomic Nerve Stimulation in the Treatment of Heart Failure

    OpenAIRE

    Kobayashi, Mariko; Massiello, Alex; Karimov, Jamshid H.; Van Wagoner, David R.; Fukamachi, Kiyotaka

    2013-01-01

    Research on the therapeutic modulation of cardiac autonomic tone by electrical stimulation has yielded encouraging early clinical results. Vagus nerve stimulation has reduced the rates of morbidity and sudden death from heart failure, but therapeutic vagus nerve stimulation is limited by side effects of hypotension and bradycardia. Sympathetic nerve stimulation that has been implemented in the experiment may exacerbate the sympathetic-dominated autonomic imbalance. In contrast, concurrent sti...

  8. Cardiac Autonomic Nerve Stimulation in the Treatment of Heart Failure

    OpenAIRE

    Kobayashi, Mariko; Massiello, Alex; Karimov, Jamshid H.; Van Wagoner, David R.; Fukamachi, Kiyotaka

    2013-01-01

    Research on the therapeutic modulation of cardiac autonomic tone by electrical stimulation has yielded encouraging early clinical results. Vagus nerve stimulation has reduced the rates of morbidity and sudden death from heart failure, but therapeutic vagus nerve stimulation is limited by side effects of hypotension and bradycardia. Sympathetic nerve stimulation that has been implemented in the experiment may exacerbate the sympathetic-dominated autonomic imbalance. In contrast, concurrent sti...

  9. A figure of merit for neural electrical stimulation circuits.

    Science.gov (United States)

    Kolbl, Florian; Demosthenous, Andreas

    2015-01-01

    Electrical stimulators are widely used in neuro-prostheses. Many different implementations exist. However, no quantitative ranking criterion is available to allow meaningful comparison of the various stimulation circuits and systems to aid the designer. This paper presents a novel Figure of Merit (FOM) dedicated to stimulation circuits and systems. The proposed optimization performance metric takes into account tissue safety conditions and energy efficiency which can be evaluated by measurement. The FOM is used to rank several stimulator circuits and systems.

  10. Facial nerve stimulation after cochlear implantation: our experience

    OpenAIRE

    BERRETTINI, S.; De Vito, A.; Bruschini, L.; PASSETTI, S.; Forli, F.

    2011-01-01

    SUMMARY Post-implantation facial nerve stimulation is one of the best known and most frequent complications of the cochlear implant procedure. Some conditions, such as otosclerosis and cochlear malformations, as well as high stimulation levels that may be necessary in patients with long auditory deprivation, expose patients to a higher risk of developing post-implant facial nerve stimulation. Facial nerve stimulation can frequently be resolved with minimal changes in speech processor fitting ...

  11. Illusory sensation of movement induced by repetitive transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Christensen, Mark Schram; Lundbye-Jensen, J.; Grey, M.J.;

    2010-01-01

    Human movement sense relies on both somatosensory feedback and on knowledge of the motor commands used to produce the movement. We have induced a movement illusion using repetitive transcranial magnetic stimulation over primary motor cortex and dorsal premotor cortex in the absence of limb moveme...... premotor cortex stimulation was less affected by sensory and motor deprivation than was primary motor cortex stimulation. We propose that repetitive transcranial magnetic stimulation over dorsal premotor cortex produces a corollary discharge that is perceived as movement....

  12. 21 CFR 882.5820 - Implanted cerebellar stimulator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implanted cerebellar stimulator. 882.5820 Section... (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5820 Implanted cerebellar stimulator. (a) Identification. An implanted cerebellar stimulator is a device used to...

  13. 21 CFR 882.5860 - Implanted neuromuscular stimulator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Implanted neuromuscular stimulator. 882.5860... (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5860 Implanted neuromuscular stimulator. (a) Identification. An implanted neuromuscular stimulator is a device that...

  14. Functional Electrical Stimulation in Children and Adolescents with Cerebral Palsy

    Science.gov (United States)

    van der Linden, Marietta

    2012-01-01

    In this article, the author talks about functional electrical stimulation in children and adolescents with cerebral palsy. Functional electrical stimulation (FES) is defined as the electrical stimulation of muscles that have impaired motor control, in order to produce a contraction to obtain functionally useful movement. It was first proposed in…

  15. 21 CFR 882.5800 - Cranial electrotherapy stimulator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cranial electrotherapy stimulator. 882.5800 Section 882.5800 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... electrotherapy stimulator. (a) Identification. A cranial electrotherapy stimulator is a device that...

  16. Cranial electrotherapy stimulation for treatment of anxiety, depression, and insomnia.

    Science.gov (United States)

    Kirsch, Daniel L; Nichols, Francine

    2013-03-01

    Cranial electrotherapy stimulation is a prescriptive medical device that delivers a mild form of electrical stimulation to the brain for the treatment of anxiety, depression, and insomnia. It is supported by more than 40 years of research demonstrating its effectiveness in several mechanistic studies and greater than 100 clinical studies. Adverse effects are rare (electrotherapy stimulation may also be used as an adjunctive therapy.

  17. 21 CFR 890.5860 - Ultrasound and muscle stimulator.

    Science.gov (United States)

    2010-04-01

    ..., muscle spasms, and joint contractures, but not for the treatment of malignancies. The device also passes... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasound and muscle stimulator. 890.5860 Section... Ultrasound and muscle stimulator. (a) Ultrasound and muscle stimulator for use in applying therapeutic deep...

  18. Transcranial direct current stimulation: electrode montage in stroke.

    Science.gov (United States)

    Mahmoudi, Hooman; Borhani Haghighi, Afshin; Petramfar, Peyman; Jahanshahi, Sepehr; Salehi, Zahra; Fregni, Felipe

    2011-01-01

    Neurophysiological and computer modelling studies have shown that electrode montage is a critical parameter to determine the neuromodulatory effects of transcranial direct current stimulation (tDCS). We tested these results clinically by systematically investigating optimal tDCS electrode montage in stroke. Ten patients received in a counterbalanced and randomised order the following conditions of stimulation (i) anodal stimulation of affected M1 (primary motor cortex) and cathodal stimulation of unaffected M1 ('bilateral tDCS'); (ii) anodal stimulation of affected M1 and cathodal stimulation of contralateral supraorbital area ('anodal tDCS'); (iii) cathodal stimulation of unaffected M1 and anodal stimulation of contralateral supraorbital area ('cathodal tDCS'); (iv) anodal stimulation of affected M1 and cathodal stimulation of contralateral deltoid muscle ('extra-cephalic tDCS') and (v) sham stimulation. We used the Jebsen-Taylor Test (JTT) as a widely accepted measure of upper limb function. Bilateral tDCS, anodal tDCS and cathodal tDCS were shown to be associated with significant improvements on the JTT. Placing the reference electrode in an extracephalic position and use of sham stimulation did not induce any significant effects. This small sham controlled cross-over clinical trial is important to provide additional data on the clinical effects of tDCS in stroke and for planning and designing future large tDCS trials in patients with stroke.

  19. Functional Electrical Stimulation in Children and Adolescents with Cerebral Palsy

    Science.gov (United States)

    van der Linden, Marietta

    2012-01-01

    In this article, the author talks about functional electrical stimulation in children and adolescents with cerebral palsy. Functional electrical stimulation (FES) is defined as the electrical stimulation of muscles that have impaired motor control, in order to produce a contraction to obtain functionally useful movement. It was first proposed in…

  20. 21 CFR 868.2775 - Electrical peripheral nerve stimulator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Electrical peripheral nerve stimulator. 868.2775... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2775 Electrical peripheral nerve stimulator. (a) Identification. An electrical peripheral nerve stimulator (neuromuscular blockade monitor)...

  1. 21 CFR 882.1870 - Evoked response electrical stimulator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Evoked response electrical stimulator. 882.1870... electrical stimulator. (a) Identification. An evoked response electrical stimulator is a device used to apply an electrical stimulus to a patient by means of skin electrodes for the purpose of measuring...

  2. FUNCTIONAL ELECTRICAL STIMULATION FOR CONTROL OF EPILEPTIC SEIZURES

    DEFF Research Database (Denmark)

    Jiao, Jianhang

    parameters regarding their ability to inhibit seizures. The present thesis hypothesized that the antiepileptic effects of vagus nerve stimulation and spinal cord stimulation could be improved by using higher stimulation frequencies than those that are currently used in clinic or proposed in the literature....

  3. Maturation of Human Fetal Responses to Vibroacoustic Stimulation.

    Science.gov (United States)

    Kisilevsky, Barbara S.; And Others

    1992-01-01

    Fetuses received vibroacoustic stimulation while movement and heart rate were monitored. From 29 weeks, at least 83 percent of fetuses responded to stimulation with heart rate acceleration. Between 26 and 36 weeks, the percentage of fetuses responding to stimulation with movement increased from 58 to 100 percent. (BC)

  4. Design of efficient and safe neural stimulators: a multidisciplinary approach

    NARCIS (Netherlands)

    Van Dongen, M.N.

    2015-01-01

    Neural stimulation is an established treatment methodology for an increasing number of diseases. Electrical Stimulation injects a stimulation signal through electrodes that are implanted in the target area of the central or peripheral nervous system in order to evoke a specific neuronal response tha

  5. Laboratory investigation of microelectronics-based stimulators for large-scale suprachoroidal transretinal stimulation (STS).

    Science.gov (United States)

    Ohta, J; Tokuda, T; Kagawa, K; Sugitani, S; Taniyama, M; Uehara, A; Terasawa, Y; Nakauchi, K; Fujikado, T; Tano, Y

    2007-03-01

    This paper describes the technological developments underlying the realization of a reliable and reproducible microchip-based stimulator with a large number of stimulus electrodes. A microchip-based stimulator with over 500 electrodes for suprachoroidal transretinal stimulation (STS) is proposed in this paper, and an example is presented. To enhance reliability and reproducibility for such a large array, we introduce a flip-chip bonding technique and place microchips on the reverse side of a substrate. A square microchip of size 600 microm was fabricated using 0.35 microm standard CMOS process technology. Twelve microchips were flip-chip bonded on a polyimide substrate through Au bumps. To evaluate the feasibility of the proposed device, we successfully fabricated a stimulator with 12 microchips and 118 electrodes made of Pt/Au bumps, and demonstrated their operation in a saline solution for 2 weeks. Also, to evaluate the device operation in vivo, a stimulator with one active IrO(x) electrode was implanted into the scleral pocket of a rabbit and electrical evoked potential (EEP) signals with a threshold of 100 microA were obtained. We also fabricated a simulator with 64 microchips that has 576 electrodes (9 electrodes in a microchip times 64 microchips).

  6. Why intra-epidermal electrical stimulation achieves stimulation of small fibres selectively: a simulation study

    Science.gov (United States)

    Motogi, Jun; Sugiyama, Yukiya; Laakso, Ilkka; Hirata, Akimasa; Inui, Koji; Tamura, Manabu; Muragaki, Yoshihiro

    2016-06-01

    The in situ electric field in the peripheral nerve of the skin is investigated to discuss the selective stimulation of nerve fibres. Coaxial planar electrodes with and without intra-epidermal needle tip were considered as electrodes of a stimulator. From electromagnetic analysis, the tip depth of the intra-epidermal electrode should be larger than the thickness of the stratum corneum, the electrical conductivity of which is much lower than the remaining tissue. The effect of different radii of the outer ring electrode on the in situ electric field is marginal. The minimum threshold in situ electric field (rheobase) for free nerve endings is estimated to be 6.3 kV m-1. The possible volume for electrostimulation, which can be obtained from the in situ electric field distribution, becomes deeper and narrower with increasing needle depth, suggesting that possible stimulation sites may be controlled by changing the needle depth. The injection current amplitude should be adjusted when changing the needle depth because the peak field strength also changes. This study shows that intra-epidermal electrical stimulation can achieve stimulation of small fibres selectively, because Aβ-, Aδ-, and C-fibre terminals are located at different depths in the skin.

  7. Carbon Nanofiber Nanoelectrodes for Neural Stimulation and Chemical Detection: The Era of Smart Deep Brain Stimulation

    Science.gov (United States)

    Koehne, Jessica E.

    2016-01-01

    A sensor platform based on vertically aligned carbon nanofibers (CNFs) has been developed. Their inherent nanometer scale, high conductivity, wide potential window, good biocompatibility and well-defined surface chemistry make them ideal candidates as biosensor electrodes. Here, we report two studies using vertically aligned CNF nanoelectrodes for biomedical applications. CNF arrays are investigated as neural stimulation and neurotransmitter recording electrodes for application in deep brain stimulation (DBS). Polypyrrole coated CNF nanoelectrodes have shown great promise as stimulating electrodes due to their large surface area, low impedance, biocompatibility and capacity for highly localized stimulation. CNFs embedded in SiO2 have been used as sensing electrodes for neurotransmitter detection. Our approach combines a multiplexed CNF electrode chip, developed at NASA Ames Research Center, with the Wireless Instantaneous Neurotransmitter Concentration Sensor (WINCS) system, developed at the Mayo Clinic. Preliminary results indicate that the CNF nanoelectrode arrays are easily integrated with WINCS for neurotransmitter detection in a multiplexed array format. In the future, combining CNF based stimulating and recording electrodes with WINCS may lay the foundation for an implantable "smart" therapeutic system that utilizes neurochemical feedback control while likely resulting in increased DBS application in various neuropsychiatric disorders. In total, our goal is to take advantage of the nanostructure of CNF arrays for biosensing studies requiring ultrahigh sensitivity, high-degree of miniaturization, and selective biofunctionalization.

  8. Carbon Nanofiber Nanoelectrodes for Neural Stimulation and Chemical Detection: The Era of "Smart" Deep Brain Stimulation

    Science.gov (United States)

    Koehne, Jessica E.

    2016-01-01

    A sensor platform based on vertically aligned carbon nanofibers (CNFs) has been developed. Their inherent nanometer scale, high conductivity, wide potential window, good biocompatibility and well-defined surface chemistry make them ideal candidates as biosensor electrodes. Here, we report two studies using vertically aligned CNF nanoelectrodes for biomedical applications. CNF arrays are investigated as neural stimulation and neurotransmitter recording electrodes for application in deep brain stimulation (DBS). Polypyrrole coated CNF nanoelectrodes have shown great promise as stimulating electrodes due to their large surface area, low impedance, biocompatibility and capacity for highly localized stimulation. CNFs embedded in SiO2 have been used as sensing electrodes for neurotransmitter detection. Our approach combines a multiplexed CNF electrode chip, developed at NASA Ames Research Center, with the Wireless Instantaneous Neurotransmitter Concentration Sensor (WINCS) system, developed at the Mayo Clinic. Preliminary results indicate that the CNF nanoelectrode arrays are easily integrated with WINCS for neurotransmitter detection in a multiplexed array format. In the future, combining CNF based stimulating and recording electrodes with WINCS may lay the foundation for an implantable smart therapeutic system that utilizes neurochemical feedback control while likely resulting in increased DBS application in various neuropsychiatric disorders. In total, our goal is to take advantage of the nanostructure of CNF arrays for biosensing studies requiring ultrahigh sensitivity, high-degree of miniaturization, and selective biofunctionalization.

  9. Approximating transcranial magnetic stimulation with electric stimulation in mouse: a simulation study.

    Science.gov (United States)

    Barnes, Walter L; Lee, Won Hee; Peterchev, Angel V

    2014-01-01

    Rodent models are valuable for preclinical examination of novel therapeutic techniques, including transcranial magnetic stimulation (TMS). However, comparison of TMS effects in rodents and humans is confounded by inaccurate scaling of the spatial extent of the induced electric field in rodents. The electric field is substantially less focal in rodent models of TMS due to the technical restrictions of making very small coils that can handle the currents required for TMS. We examine the electric field distributions generated by various electrode configurations of electric stimulation in an inhomogeneous high-resolution finite element mouse model, and show that the electric field distributions produced by human TMS can be approximated by electric stimulation in mouse. Based on these results and the limits of magnetic stimulation in mice, we argue that the most practical and accurate way to model focal TMS in mice is electric stimulation through either cortical surface electrodes or electrodes implanted halfway through the mouse cranium. This approach could allow much more accurate approximation of the human TMS electric field focality and strength than that offered by TMS in mouse, enabling, for example, focal targeting of specific cortical regions, which is common in human TMS paradigms.

  10. Improving Sensorimotor Function Using Stochastic Vestibular Stimulation

    Science.gov (United States)

    Galvan, R. C.; Clark, T. K.; Merfeld, D. M.; Bloomberg, J. J.; Mulavara, A. P.; Oman, C. M.

    2014-01-01

    Astronauts experience sensorimotor changes during spaceflight, particularly during G-transition phases. Post flight sensorimotor changes may include postural and gait instability, spatial disorientation, and visual performance decrements, all of which can degrade operational capabilities of the astronauts and endanger the crew. Crewmember safety would be improved if these detrimental effects of spaceflight could be mitigated by a sensorimotor countermeasure and even further if adaptation to baseline could be facilitated. The goal of this research is to investigate the potential use of stochastic vestibular stimulation (SVS) as a technology to improve sensorimotor function. We hypothesize that low levels of SVS will improve sensorimotor performance through stochastic resonance (SR). The SR phenomenon occurs when the response of a nonlinear system to a weak input signal is optimized by the application of a particular nonzero level of noise. Two studies have been initiated to investigate the beneficial effects and potential practical usage of SVS. In both studies, electrical vestibular stimulation is applied via electrodes on the mastoid processes using a constant current stimulator. The first study aims to determine the repeatability of the effect of vestibular stimulation on sensorimotor performance and perception in order to better understand the practical use of SVS. The beneficial effect of low levels of SVS on balance performance has been shown in the past. This research uses the same balance task repeated multiple times within a day and across days to study the repeatability of the stimulation effects. The balance test consists of 50 sec trials in which the subject stands with his or her feet together, arms crossed, and eyes closed on compliant foam. Varying levels of SVS, ranging from 0-700 micro A, are applied across different trials. The subject-specific optimal SVS level is that which results in the best balance performance as measured by inertial

  11. Stimulated Brillouin scatter and stimulated ion Bernstein scatter during electron gyroharmonic heating experiments

    Science.gov (United States)

    Fu, H.; Scales, W. A.; Bernhardt, P. A.; Samimi, A.; Mahmoudian, A.; Briczinski, S. J.; McCarrick, M. J.

    2013-09-01

    Results of secondary radiation, Stimulated Electromagnetic Emission (SEE), produced during ionospheric modification experiments using ground-based high-power radio waves are reported. These results obtained at the High Frequency Active Auroral Research Program (HAARP) facility specifically considered the generation of Magnetized Stimulated Brillouin Scatter (MSBS) and Stimulated Ion Bernstein Scatter (SIBS) lines in the SEE spectrum when the transmitter frequency is near harmonics of the electron gyrofrequency. The heater antenna beam angle effect was investigated on MSBS in detail and shows a new spectral line postulated to be generated near the upper hybrid resonance region due to ion acoustic wave interaction. Frequency sweeping experiments near the electron gyroharmonics show for the first time the transition from MSBS to SIBS lines as the heater pump frequency approaches the gyroharmonic. Significantly far from the gyroharmonic, MSBS lines dominate, while close to the gyroharmonic, SIBS lines strengthen while MSBS lines weaken. New possibilities for diagnostic information are discussed in light of these new observations.

  12. [Repetitive transcranial magnetic stimulation in depression; stimulation of the brain in order to cure the psyche].

    Science.gov (United States)

    Helmich, R C; Snijders, A H; Verkes, R J; Bloem, B R

    2004-02-28

    Transcranial magnetic stimulation (TMS) is a non-invasive approach to briefly stimulate or inhibit cortical brain areas. A novel approach entails the delivery of repetitive TMS pulses (rTMS) at a fixed frequency. In rTMS cortical activity is altered beyond the period of actual stimulation. The changes occur locally as well as at a distance in functionally connected brain areas. These features render rTMS a suitable tool to study normal brain functions and the pathophysiology of brain diseases. Furthermore, it is expected that rTMS could be used as a novel therapy for neurological or psychiatric diseases characterised by abnormal cortical activation. This possibility has been studied mostly in patients suffering from depression, where rTMS has been used to restore normal activity in the hypoactive prefrontal cortex. Despite statistically significant therapeutic effects in small sized trials, the clinical implications are still limited.

  13. Repetitive transcranial magnetic stimulation in psychiatry

    Directory of Open Access Journals (Sweden)

    Biswa Ranjan Mishra

    2011-01-01

    Full Text Available Repetitive transcranial magnetic stimulation (rTMS is a non-invasive and relatively painless tool that has been used to study various cognitive functions as well as to understand the brain-behavior relationship in normal individuals as well as in those with various neuropsychiatric disorders. It has also been used as a therapeutic tool in various neuropsychiatric disorders because of its ability to specifically modulate distinct brain areas. Studies have shown that repeated stimulation at low frequency produces long-lasting inhibition, which is called as long-term depression, whereas repeated high-frequency stimulation can produce excitation through long-term potentiation. This paper reviews the current status of rTMS as an investigative and therapeutic modality in various neuropsychiatric disorders. It has been used to study the cortical and subcortical functions, neural plasticity and brain mapping in normal individuals and in various neuropsychiatric disorders. rTMS has been most promising in the treatment of depression, with an overall milder adverse effect profile compared with electroconvulsive therapy. In other neuropsychiatric disorders such as schizophrenia, mania, epilepsy and substance abuse, it has been found to be useful, although further studies are required to establish therapeutic efficacy. It appears to be ineffective in the treatment of obsessive compulsive disorder. There is a paucity of studies of efficacy and safety of rTMS in pediatric and geriatric population. Although it appears safe, further research is required to optimize its efficacy and reduce the side-effects. Magnetic seizure therapy, which involves producing seizures akin to electroconvulsive therapy, appears to be of comparable efficacy in the treatment of depression with less cognitive adverse effects.

  14. Hydraulic-fracture stimulation treatments at East Mesa, Well 58-30. Geothermal-reservoir well-stimulation program

    Energy Technology Data Exchange (ETDEWEB)

    1981-02-01

    East Mesa Well 58-30 was selected for two stimulation treatments: a conventional hydraulic fracture in a deep, low permeability interval, and a dendritic fracture in a shallow, high permeability interval of completion. The well selection, pre-stimulation evaluation, fracture treatment design, and post-stimulation evaluation are presented.

  15. A systematic review investigating the relationship between efficacy and stimulation parameters when using transcutaneous electrical nerve stimulation after knee arthroplasty

    Directory of Open Access Journals (Sweden)

    David Beckwée

    2014-06-01

    Full Text Available Objective: To evaluate the clinical efficacy of transcutaneous electric nerve stimulation in the treatment of postoperative knee arthroplasty pain and to relate these results to the stimulation parameters used. Data Sources: PubMed, Pedro and Web of Knowledge were systematically screened for studies investigating effects of transcutaneous electric nerve stimulation on postoperative knee arthroplasty pain. Review Methods: Studies were screened for their methodological and therapeutical quality. We appraised the influence of the stimulation settings used and indicated whether or not a neurophysiological and/or mechanistic rationale was given for these stimulation settings. Results: A total of 5 articles met the inclusion criteria. In total, 347 patients were investigated. The number of patients who received some form of transcutaneous electric nerve stimulation was 117, and 54 patients received sham transcutaneous electric nerve stimulation. Pain was the primary outcome in all studies. The stimulation settings used in the studies (n = 2 that reported significant effects differed from the others as they implemented a submaximal stimulation intensity. Stimulation parameters were heterogeneous, and only one study provided a rationale for them. Conclusion: This review reveals that an effect of transcutaneous electric nerve stimulation might have been missed due to low methodological and therapeutical quality. Justifying the choice of transcutaneous electric nerve stimulation parameters may improve therapeutical quality.

  16. Cranial electrotherapy stimulation and transcranial pulsed current stimulation: a computer based high-resolution modeling study.

    Science.gov (United States)

    Datta, Abhishek; Dmochowski, Jacek P; Guleyupoglu, Berkan; Bikson, Marom; Fregni, Felipe

    2013-01-15

    The field of non-invasive brain stimulation has developed significantly over the last two decades. Though two techniques of noninvasive brain stimulation--transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS)--are becoming established tools for research in neuroscience and for some clinical applications, related techniques that also show some promising clinical results have not been developed at the same pace. One of these related techniques is cranial electrotherapy stimulation (CES), a class of transcranial pulsed current stimulation (tPCS). In order to understand further the mechanisms of CES, we aimed to model CES using a magnetic resonance imaging (MRI)-derived finite element head model including cortical and also subcortical structures. Cortical electric field (current density) peak intensities and distributions were analyzed. We evaluated different electrode configurations of CES including in-ear and over-ear montages. Our results confirm that significant amounts of current pass the skull and reach cortical and subcortical structures. In addition, depending on the montage, induced currents at subcortical areas, such as midbrain, pons, thalamus and hypothalamus are of similar magnitude than that of cortical areas. Incremental variations of electrode position on the head surface also influence which cortical regions are modulated. The high-resolution modeling predictions suggest that details of electrode montage influence current flow through superficial and deep structures. Finally we present laptop based methods for tPCS dose design using dominant frequency and spherical models. These modeling predictions and tools are the first step to advance rational and optimized use of tPCS and CES.

  17. Combined transcranial alternating current stimulation and continuous theta burst stimulation: a novel approach for neuroplasticity induction.

    Science.gov (United States)

    Goldsworthy, Mitchell R; Vallence, Ann-Maree; Yang, Ruiting; Pitcher, Julia B; Ridding, Michael C

    2016-02-01

    Non-invasive brain stimulation can induce functionally relevant plasticity in the human cortex, making it potentially useful as a therapeutic tool. However, the induced changes are highly variable between individuals, potentially limiting research and clinical utility. One factor that might contribute to this variability is the level of cortical inhibition at the time of stimulation. The alpha rhythm (~ 8-13 Hz) recorded with electroencephalography (EEG) is thought to reflect pulsatile cortical inhibition; therefore, targeting non-invasive brain stimulation to particular phases of the alpha rhythm may provide an approach to enhance plasticity induction. Transcranial alternating current stimulation (tACS) has been shown to entrain cortical oscillations in a frequency-specific manner. We investigated whether the neuroplastic response to continuous theta burst stimulation (cTBS) was enhanced by timing bursts of stimuli to the peak or the trough of a tACS-imposed alpha rhythm. While motor evoked potentials (MEPs) were unaffected when cTBS was applied in-phase with the peak of the tACS-imposed oscillation, MEP depression was enhanced when cTBS was applied in-phase with the trough. This enhanced MEP depression was dependent on the individual peak frequency of the endogenous alpha rhythm recorded with EEG prior to stimulation, and was strongest in those participants classified as non-responders to standard cTBS. These findings suggest that tACS may be used in combination with cTBS to enhance the plasticity response. Furthermore, the peak frequency of endogenous alpha, as measured with EEG, may be used as a simple marker to pre-select those individuals likely to benefit from this approach.

  18. Improving the luteal phase after ovarian stimulation

    DEFF Research Database (Denmark)

    Andersen, Claus Yding; Vilbour Andersen, K

    2014-01-01

    The human chorionic gonadotrophin (HCG) trigger used for final follicular maturation in connection with assisted reproduction treatment combines ovulation induction and early luteal-phase stimulation of the corpora lutea. The use of a gonadotrophin-releasing hormone agonist (GnRHa) for final...... follicular maturation has, however, for the first time allowed a separation of the ovulatory signal from the early luteal-phase support. This has generated new information that may improve the currently employed luteal-phase support. Thus, combined results from a number of randomized controlled trials using...

  19. The Stimulated Raman Spectrum of Cyanogen

    Science.gov (United States)

    Bermejo; Escribano; Santos

    1997-11-01

    The Raman spectrum of cyanogen 12C214N2 has been investigated at nearly Doppler resolution by means of the Stimulated Raman technique. The regions around the Q branches of the nu1 (2330 cm-1) and nu2 (845 cm-1) vibrations have been recorded. Besides the fundamentals, hot bands arising from v5 = 1, v5 = 2, and v4 = 1 have been observed. The spectra have been analyzed, and rotational constants for the excited states have been obtained. Computer simulations of the Raman contours have been carried out as a test of the assignments. Copyright 1997 Academic Press. Copyright 1997Academic Press

  20. The analysis of thermally stimulated processes

    CERN Document Server

    Chen, R; Pamplin, Brian

    1981-01-01

    Thermally stimulated processes include a number of phenomena - either physical or chemical in nature - in which a certain property of a substance is measured during controlled heating from a 'low' temperature. Workers and graduate students in a wide spectrum of fields require an introduction to methods of extracting information from such measurements. This book gives an interdisciplinary approach to various methods which may be applied to analytical chemistry including radiation dosimetry and determination of archaeological and geological ages. In addition, recent advances are included, such

  1. On cavity modification of stimulated Raman scattering

    CERN Document Server

    Matsko, A B; Letargat, R J; Ilchenko, V S; Maleki, L

    2003-01-01

    We study theoretically stimulated Raman scattering (SRS) in a nonlinear dielectric microcavity and compare SRS thresholds for the cavity and the bulk material it is made of. We show that cavity SRS enhancement results solely from the intensity build up in the cavity and from the differences of the SRS dynamics in free and confined space. There is no significant modification of the Raman gain due to cavity QED effects. We show that the SRS threshold depends significantly on the nature of the dominating cavity decay as well as on the coupling technique with the cavity used for SRS measurements.

  2. Stimulation and recording electrodes for neural prostheses

    CERN Document Server

    Pour Aryan, Naser; Rothermel, Albrecht

    2015-01-01

    This book provides readers with basic principles of the electrochemistry of the electrodes used in modern, implantable neural prostheses. The authors discuss the boundaries and conditions in which the electrodes continue to function properly for long time spans, which are required when designing neural stimulator devices for long-term in vivo applications. Two kinds of electrode materials, titanium nitride and iridium are discussed extensively, both qualitatively and quantitatively. The influence of the counter electrode on the safety margins and electrode lifetime in a two electrode system is explained. Electrode modeling is handled in a final chapter.

  3. Deep Brain Stimulation for Movement Disorders.

    Science.gov (United States)

    Revell, Maria A

    2015-12-01

    Disruption in the interaction between the central nervous system, nerves, and muscles cause movement disorders. These disorders can negatively affect quality of life. Deep brain stimulation (DBS) has been identified as a therapy for Parkinson disease and essential tremor that has significant advantages compared with medicinal therapies. Surgical intervention for these disorders before DBS included ablative therapies such as thalamotomy and pallidotomy. These procedures were not reversible and did not allow for treatment adjustments. The advent of DBS progressed therapies for significant movement disorders into the realm of being reversible and adjustable based on patient symptoms.

  4. Optically Stimulated Luminescence Fundamentals and Applications

    CERN Document Server

    McKeever, Stephen

    2011-01-01

    The book discusses advanced modern applications of optically stimulated luminescence including the appropriate fundamentals of the process. It features major chapters on the use of OSL in space radiation dosimetry, medical physics, personnel dosimetry, security, solid-state physics and other related applications. In each case, the underlying theory is discussed on an as-needed basis for a complete understanding of the phenomena, but with an emphasis of the practical applications of the technique. After an introductory chapter, Chapters 2 to 6 cover basic theory and practical aspects, personal

  5. Isoconversional kinetics of thermally stimulated processes

    CERN Document Server

    Vyazovkin, Sergey

    2015-01-01

    The use of isoconversional kinetic methods for analysis of thermogravimetric and calorimetric data on thermally stimulated processes is quickly growing in popularity. The purpose of this book is to create the first comprehensive resource on the theory and applications of isoconversional methodology. The book introduces the reader to the kinetics of physical and chemical condensed phase processes that occur as a result of changing temperature and discusses how isoconversional analysis can provide important kinetic insights into them. The book will help the readers to develop a better understanding of the methodology, and promote its efficient usage and successful development.

  6. Asystole Following Profound Vagal Stimulation During Hepatectomy

    Directory of Open Access Journals (Sweden)

    Preeta John

    2008-01-01

    Full Text Available Asystole in a non laparoscopic upper abdominal surgery following intense vagal stimulation is a rare event. This case report highlights the need for awareness of such a complication when a thoracic epidural anaesthetic has been given in addition to a general anaesthetic for an upper abdominal procedure. A combined thoracic epidural and general anaesthetic was given. The anterior abdominal wall was retracted forty minutes after administration of the epidural bolus. This maneuver resulted in a profound vagal response with bradycardia and asystole. The patient was resuscitated successfully with a cardiac massage, atropine and adrenaline and the surgery was resumed. Surgery lasted eleven hours and was uneventful.

  7. Optogenetics and deep brain stimulation neurotechnologies.

    Science.gov (United States)

    Kondabolu, Krishnakanth; Kowalski, Marek Mateusz; Roberts, Erik Andrew; Han, Xue

    2015-01-01

    Brain neural network is composed of densely packed, intricately wired neurons whose activity patterns ultimately give rise to every behavior, thought, or emotion that we experience. Over the past decade, a novel neurotechnique, optogenetics that combines light and genetic methods to control or monitor neural activity patterns, has proven to be revolutionary in understanding the functional role of specific neural circuits. We here briefly describe recent advance in optogenetics and compare optogenetics with deep brain stimulation technology that holds the promise for treating many neurological and psychiatric disorders.

  8. Functional electrical stimulation bicycle ergometry: patient perceptions.

    Science.gov (United States)

    Sipski, M L; Delisa, J A; Schweer, S

    1989-06-01

    Forty-seven patients who had participated in a clinical electrical stimulation ergometry program were administered a questionnaire to determine their perceptions of the therapy. Improved endurance was reported by 62% of paraplegics and 65% of quadriplegics. Sixty-two percent of paraplegics and 56% of quadriplegics reported improved self-image, while 54% of paraplegics and 77% of quadriplegics perceived their appearance was better. Thirty-nine percent of paraplegics and 24% of quadriplegics noted decreased lower extremity edema with training. Six out of nine patients with a previous history of neurogenic pain noted an increase in pain, which caused them to leave the program.

  9. Closed-loop transcranial alternating current stimulation of slow oscillations

    Directory of Open Access Journals (Sweden)

    Wilde Christian

    2015-09-01

    Full Text Available Transcranial alternating current stimulation (tACS is an emerging non-invasive tool for modulating brain oscillations. There is evidence that weak oscillatory electrical stimulation during sleep can entrain cortical slow oscillations to improve the memory consolidation in rodents and humans. Using a novel method and a custom built stimulation device, automatic stimulation of slow oscillations in-phase with the endogenous activity in a real-time closed-loop setup is possible. Preliminary data from neuroplasticity experiments show a high detection performance of the proposed method, electrical measurements demonstrate the outstanding quality of the presented stimulation device.

  10. Hypersexuality following subthalamic nucleus stimulation for Parkinson's disease.

    Science.gov (United States)

    Doshi, Paresh; Bhargava, Pranshu

    2008-01-01

    Subthalamic nucleus (STN) stimulation is an established surgical treatment for Parkinson's disease (PD). Though the motor benefits of STN stimulation are well understood, its cognitive and behavioral effects are still not fully understood. Manic psychosis, hypersexuality, pathological gambling and mood swings are associated with advanced PD. There have been reports to suggest improvement or worsening in these symptoms following STN deep brain stimulation (DBS). We report two cases as the sole behavioral side-effects of STN stimulation despite good clinical improvement on long-term follow-up. These patients and literature review suggests the complex role of STN stimulation in motor and behavioral control.

  11. Hypersexuality following subthalamic nucleus stimulation for Parkinson′s disease

    Directory of Open Access Journals (Sweden)

    Doshi Paresh

    2008-01-01

    Full Text Available Subthalamic nucleus (STN stimulation is an established surgical treatment for Parkinson′s disease (PD. Though the motor benefits of STN stimulation are well understood, its cognitive and behavioral effects are still not fully understood. Manic psychosis, hypersexuality, pathological gambling and mood swings are associated with advanced PD. There have been reports to suggest improvement or worsening in these symptoms following STN deep brain stimulation (DBS. We report two cases as the sole behavioral side-effects of STN stimulation despite good clinical improvement on long-term follow-up. These patients and literature review suggests the complex role of STN stimulation in motor and behavioral control.

  12. Nanoscale Mechanical Stimulation of Human Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    H Nikukar

    2014-05-01

    We observed significant responses after 1 and 2-week stimulations in cell number, cell shapes and phenotypical markers. Microarray was performed for all groups. Cell count showed normal cell growth with stimulation. However, cell surface area, cell perimeter, and arboration after 1-week stimulation showed significant increases. Immunofluorescent studies have showed significant increase in osteocalcin production after stimulation. Conclusions: Nanoscale mechanical vibration showed significant changes in human mesenchymal stem cell behaviours. Cell morphology changed to become more polygonal and increased expression of the osteoblast markers were noted. These findings with gene regulation changes suggesting nanoscale mechanostimulation has stimulated osteoblastogenesis.  Keywords:  Mesenchymal, Nanoscale, Stem Cells.

  13. Paired associative stimulation targeting the tibialis anterior muscle using either mono or biphasic transcranial magnetic stimulation

    DEFF Research Database (Denmark)

    Mrachacz-Kersting, Natalie; Stevenson, Andrew James Thomas

    2017-01-01

    a reduced intensity of this pulse would lead to significant changes as has been reported for hand muscles using a monophasic TMS pulse. Three interventions were investigated: (1) suprathreshold PAbi-PAS (n = 11); (2) suprathreshold PAmono-PAS (n = 11) where PAS was applied using a biphasic or monophasic......Paired associative stimulation (PAS) protocols induce plastic changes within the motor cortex. The objectives of this study were to investigate PAS effects targeting the tibialis anterior (TA) muscle using a biphasic transcranial magnetic stimulation (TMS) pulse form and, to determine whether...

  14. Optimal number of stimulation contacts for coordinated reset neuromodulation

    Directory of Open Access Journals (Sweden)

    Borys eLysyansky

    2013-07-01

    Full Text Available In this computational study we investigatecoordinated reset (CR neuromodulation designed for an effective controlof synchronization by multi-site stimulation of neuronal target populations. This method was suggested to effectively counteract pathological neuronal synchronycharacteristic for several neurological disorders. We studyhow many stimulation sites are required for optimal CR-induced desynchronization. We found that a moderate increase of the number of stimulation sitesmay significantly prolong the post-stimulation desynchronized transientafter the stimulation is completely switched off. This can, in turn,reduce the amount of the administered stimulation current for theintermittent ON-OFF CR stimulation protocol, where time intervalswith stimulation ON are recurrently followed by time intervals withstimulation OFF. In addition, we found that the optimal number ofstimulation sites essentially depends on how strongly the administeredcurrent decays within the neuronal tissue with increasing distancefrom the stimulation site. In particular, for a broad spatial stimulationprofile, i.e., for a weak spatial decay rate of the stimulation current,CR stimulation can optimally be delivered via a small number of stimulationsites. Our findings may contribute to an optimization of therapeutic applications of CR neuromodulation.

  15. A model of auditory nerve responses to electrical stimulation

    DEFF Research Database (Denmark)

    Joshi, Suyash Narendra; Dau, Torsten; Epp, Bastian

    to neutralize the charge induced during the cathodic phase. Single-neuron recordings in cat auditory nerve using monophasic electrical stimulation show, however, that both phases in isolation can generate an AP. The site of AP generation differs for both phases, being more central for the anodic phase and more...... perception of CI listeners, a model needs to incorporate the correct responsiveness of the AN to anodic and cathodic polarity. Previous models of electrical stimulation have been developed based on AN responses to symmetric biphasic stimulation or to monophasic cathodic stimulation. These models, however......, fail to correctly predict responses to anodic stimulation. This study presents a model that simulates AN responses to anodic and cathodic stimulation. The main goal was to account for the data obtained with monophasic electrical stimulation in cat AN. The model is based on an exponential integrate...

  16. Design of efficient and safe neural stimulators a multidisciplinary approach

    CERN Document Server

    van Dongen, Marijn

    2016-01-01

    This book discusses the design of neural stimulator systems which are used for the treatment of a wide variety of brain disorders such as Parkinson’s, depression and tinnitus. Whereas many existing books treating neural stimulation focus on one particular design aspect, such as the electrical design of the stimulator, this book uses a multidisciplinary approach: by combining the fields of neuroscience, electrophysiology and electrical engineering a thorough understanding of the complete neural stimulation chain is created (from the stimulation IC down to the neural cell). This multidisciplinary approach enables readers to gain new insights into stimulator design, while context is provided by presenting innovative design examples. Provides a single-source, multidisciplinary reference to the field of neural stimulation, bridging an important knowledge gap among the fields of bioelectricity, neuroscience, neuroengineering and microelectronics;Uses a top-down approach to understanding the neural activation proc...

  17. Clinical Applications of Transcranial Magnetic Stimulation in Pediatric Neurology.

    Science.gov (United States)

    Narayana, Shalini; Papanicolaou, Andrew C; McGregor, Amy; Boop, Frederick A; Wheless, James W

    2015-08-01

    Noninvasive brain stimulation is now an accepted technique that is used as a diagnostic aid and in the treatment of neuropsychiatric disorders in adults, and is being increasingly used in children. In this review, we will discuss the basic principles and safety of one noninvasive brain stimulation method, transcranial magnetic stimulation. Improvements in the spatial accuracy of transcranial magnetic stimulation are described in the context of image-guided transcranial magnetic stimulation. The article describes and provides examples of the current clinical applications of transcranial magnetic stimulation in children as an aid in the diagnosis and treatment of neuropsychiatric disorders and discusses future potential applications. Transcranial magnetic stimulation is a noninvasive tool that is safe for use in children and adolescents for functional mapping and treatment, and for many children it aids in the preoperative evaluation and the risk-benefit decision making.

  18. Subthalamic nucleus stimulation and somatosensory temporal discrimination in Parkinson's disease.

    Science.gov (United States)

    Conte, Antonella; Modugno, Nicola; Lena, Francesco; Dispenza, Sabrina; Gandolfi, Barbara; Iezzi, Ennio; Fabbrini, Giovanni; Berardelli, Alfredo

    2010-09-01

    Whereas numerous studies document the effects of dopamine medication and deep brain stimulation on motor function in patients with Parkinson's disease, few have investigated deep brain stimulation-induced changes in sensory functions. In this study of 13 patients with Parkinson's disease, we tested the effects of deep brain stimulation on the somatosensory temporal discrimination threshold. To investigate whether deep brain stimulation and dopaminergic medication induce similar changes in somatosensory discrimination, somatosensory temporal discrimination threshold values were acquired under four experimental conditions: (i) medication ON/deep brain stimulation on; (ii) medication ON/deep brain stimulation off; (iii) medication OFF/deep brain stimulation on; and (iv) medication OFF/deep brain stimulation off. Patients also underwent clinical and neuropsychological evaluations during each experimental session. Somatosensory temporal discrimination threshold values obtained in patients were compared with 13 age-matched healthy subjects. Somatosensory temporal discrimination threshold values were significantly higher in patients than in healthy subjects. In patients, somatosensory temporal discrimination threshold values were significantly lower when patients were studied in medication ON than in medication OFF conditions. Somatosensory temporal discrimination threshold values differed significantly between deep brain stimulation on and deep brain stimulation off conditions only when the patients were studied in the medication ON condition and were higher in the deep brain stimulation on/medication ON than in the deep brain stimulation off/medication ON condition. Dopamine but not subthalamic nucleus deep brain stimulation restores the altered somatosensory temporal discrimination in patients with Parkinson's disease. Deep brain stimulation degrades somatosensory temporal discrimination by modifying central somatosensory processing whereas dopamine restores the

  19. Contraction stress test by intermittent nipple stimulation.

    Science.gov (United States)

    Huddleston, J F; Sutliff, G; Robinson, D

    1984-05-01

    Although the nonstress test has generally supplanted the contraction stress test as the primary test for assessment of fetal well-being, the contraction stress test continues to be useful. Objectionable factors of the contraction stress test have included the time required to complete the test and the frequent necessity for intravenous oxytocin. The authors developed a contraction stress test protocol using contractions produced by intermittent nipple stimulation and used the method for 345 tests on 193 high-risk pregnancies during a 15-month period. The women were instructed to stimulate one breast, through their clothes, for two minutes and then to rest for five minutes. This cycle was repeated as necessary, but was interrupted whenever contractions began. Using this protocol, the authors were successful in achieving an adequate contraction frequency with every attempt, and hyperstimulation was not more frequent than previously reported with the standard contraction stress test. The average time requirement was 45 minutes. No unexplained stillbirths occurred after a negative test.

  20. Deep Brain Electrical Stimulation in Epilepsy

    Science.gov (United States)

    Rocha, Luisa L.

    2008-11-01

    The deep brain electrical stimulation has been used for the treatment of neurological disorders such as Parkinson's disease, chronic pain, depression and epilepsy. Studies carried out in human brain indicate that the application of high frequency electrical stimulation (HFS) at 130 Hz in limbic structures of patients with intractable temporal lobe epilepsy abolished clinical seizures and significantly decreased the number of interictal spikes at focus. The anticonvulsant effects of HFS seem to be more effective in patients with less severe epilepsy, an effect associated with a high GABA tissue content and a low rate of cell loss. In addition, experiments using models of epilepsy indicate that HFS (pulses of 60 μs width at 130 Hz at subthreshold current intensity) of specific brain areas avoids the acquisition of generalized seizures and enhances the postictal seizure suppression. HFS is also able to modify the status epilepticus. It is concluded that the effects of HFS may be a good strategy to reduce or avoid the epileptic activity.

  1. [Effect of cognitive stimulation in elderly community].

    Science.gov (United States)

    Apóstolo, João Luís Alves; Cardoso, Daniela Filipa Batista; Paúl, Constança; Rodrigues, Manuel Alves; Macedo, Marinha Sofia

    2016-01-01

    To demonstrate that the implementation of the Cognitive Stimulation (CS) program 'Making a Difference' (MD) improves cognition and depressive symptoms in retired community elders. This was a multicenter quasi-experimental study of 45 community dwelling elders (38 women and 7 men), with a mean age of 75.29, from 3 day-care centers in rural, semi-rural and urban environments in the central region of Portugal. Participants attended 14 sessions twice a week over seven weeks. The Montreal Cognitive Assessment (MoCA) and the Geriatric Depression Scale (GDS-15) were administered at the following three time points: baseline, post-test, and follow-up. From baseline to post-test, there is a statistically significant difference in depressive symptoms (F=7.494; P=.010) explaining 21% of the variance (partial eta squared [ηp(2)]=.21), power=.75, but there is no statistically significant difference in cognition. From post-test to follow-up, there is no difference in both cognition and depression outcomes. Our results showed improvement in elders' depressive symptoms after a seven weeks intervention program but it did not have a protective effect after the three months follow-up. No evidence was found for its efficacy in improving cognition. Cognitive stimulation may be a useful in preventing elder's depressive symptoms when included in their health promotion care plan. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

  2. Repetitive transcranial magnetic stimulation and drug addiction.

    Science.gov (United States)

    Barr, Mera S; Farzan, Faranak; Wing, Victoria C; George, Tony P; Fitzgerald, Paul B; Daskalakis, Zafiris J

    2011-10-01

    Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive brain stimulation technique that is now being tested for its ability to treat addiction. This review discusses current research approaches and results of studies which measured the therapeutic use of rTMS to treat tobacco, alcohol and illicit drug addiction. The research in this area is limited and therefore all studies evaluating the therapeutic use of rTMS in tobacco, alcohol or illicit drug addiction were retained including case studies through NCBI PubMed ( http://www.ncbi.nlm.nih.gov ) and manual searches. A total of eight studies were identified that examined the ability of rTMS to treat tobacco, alcohol and cocaine addiction. The results of this review indicate that rTMS is effective in reducing the level of cravings for smoking, alcohol, and cocaine when applied at high frequencies to the dorsolateral prefrontal cortex (DLPFC). Furthermore, these studies suggest that repeated sessions of high frequency rTMS over the DLPFC may be most effective in reducing the level of smoking and alcohol consumption. Although work in this area is limited, this review indicates that rTMS is a promising modality for treating drug addiction.

  3. Immune system stimulation by probiotic microorganisms.

    Science.gov (United States)

    Ashraf, Rabia; Shah, Nagendra P

    2014-01-01

    Probiotic organisms are claimed to offer several functional properties including stimulation of immune system. This review is presented to provide detailed informations about how probiotics stimulate our immune system. Lactobacillus rhamnosus GG, Lactobacillus casei Shirota, Bifidobacterium animalis Bb-12, Lactobacillus johnsonii La1, Bifidobacterium lactis DR10, and Saccharomyces cerevisiae boulardii are the most investigated probiotic cultures for their immunomodulation properties. Probiotics can enhance nonspecific cellular immune response characterized by activation of macrophages, natural killer (NK) cells, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in strain-specific and dose-dependent manner. Mixture and type (gram-positive and gram-negative) of probiotic organisms may induce different cytokine responses. Supplementation of probiotic organisms in infancy could help prevent immune-mediated diseases in childhood, whereas their intervention in pregnancy could affect fetal immune parameters, such as cord blood interferon (IFN)-γ levels, transforming growth factor (TGF)-β1 levels, and breast milk immunoglobulin (Ig)A. Probiotics that can be delivered via fermented milk or yogurt could improve the gut mucosal immune system by increasing the number of IgA(+) cells and cytokine-producing cells in the effector site of the intestine.

  4. Electroacoustic Stimulation: Now and into the Future

    Directory of Open Access Journals (Sweden)

    S. Irving

    2014-01-01

    Full Text Available Cochlear implants have provided hearing to hundreds of thousands of profoundly deaf people around the world. Recently, the eligibility criteria for cochlear implantation have been relaxed to include individuals who have some useful residual hearing. These recipients receive inputs from both electric and acoustic stimulation (EAS. Implant recipients who can combine these hearing modalities demonstrate pronounced benefit in speech perception, listening in background noise, and music appreciation over implant recipients that rely on electrical stimulation alone. The mechanisms bestowing this benefit are unknown, but it is likely that interaction of the electric and acoustic signals in the auditory pathway plays a role. Protection of residual hearing both during and following cochlear implantation is critical for EAS. A number of surgical refinements have been implemented to protect residual hearing, and the development of hearing-protective drug and gene therapies is promising for EAS recipients. This review outlines the current field of EAS, with a focus on interactions that are observed between these modalities in animal models. It also outlines current trends in EAS surgery and gives an overview of the drug and gene therapies that are clinically translatable and may one day provide protection of residual hearing for cochlear implant recipients.

  5. Origin and evolution of deep brain stimulation

    Directory of Open Access Journals (Sweden)

    Vittorio Alessandro eSironi

    2011-08-01

    Full Text Available This paper briefly describes how the electrical stimulation, used since antiquity to modulate the nervous system, has been a fundamental tool of neurophysiologic investigation in the second half of the 18th century and was subsequently used by the early 20th century, even for therapeutic purposes. In mid-20th century the advent of stereotactic procedures has allowed the drift from lesional to stimulating technique of deep nuclei of the brain for therapeutic purposes. In this way, DBS was born, that, over the last two decades, has led to positive results for the treatment of medically refractory Parkinson's disease, essential tremor and dystonia. In recent years, the indications for therapeutic use of DBS have been extended to epilepsy, Tourette's syndrome, psychiatric diseases (depression, obsessive-compulsive disorder, some kinds of headache, eating disorders and the minimally conscious state. The potentials of the DBS for therapeutic use are fascinating, but there are still many unresolved technical and ethical problems, concerning the identification of the targets for each disease, the selection of the patients and the evaluation of the results.

  6. Multi-site stimulation (Conference Presentation)

    Science.gov (United States)

    Chen, Rex Chin-Hao; Atry, Farid; Brodnick, Sarah K.; Novello, Joseph; Suminski, Aaron; Pisaniello, Jane; Williams, Justin; Pashaie, Ramin

    2017-02-01

    The combination of optogenetics and optical imaging modalities has become a popular tool for the investigation of neurovascular coupling. Developing a closed-loop hemodynamic control system capable of dynamically following various blood flow patterns could be beneficial to the causal investigation of neurovascular coupling. To develop this closed-loop hemodynamic control system, we have added a compensator to create a loop consisting of optogenetic stimulation, neural activities, neurovascular coupling, the evoked hemodynamic response, and a blood flow monitoring device to continuously minimize the difference between the recorded blood flow values and desired blood flow patterns. A Real-time Doppler Optical Coherence Tomography (D-OCT) is employed in this study to monitor the cross-sectional velocity profile of a vessel at a frame rate of 71 frames per second. At the same time, a proportional-derivative compensator is used to continuously adjust the pulse width of a 450nm pulsed laser that delivers 15 Hz photostimulation to the cerebral cortex of Thy1-Channelrhodopsin-2 mice. For each vessel, time-varying desired patterns and stimulation parameters were chosen according to the effect of pulse width modulation on its hemodynamic response, then proportional and derivative gains were tuned to produce a near-critically damped response. After parameter optimization, the closed-loop hemodynamic compensator successfully controlled the blood flow in middle cerebral artery branches.

  7. PROMOTION OF ACTIVE MEASURES AND EMPLOYMENT STIMULATION

    Directory of Open Access Journals (Sweden)

    LAVINIA ELISABETA POPP

    2012-01-01

    Full Text Available Researches in the field of the labour market has allowed the identification of certain specific mechanisms for employment promotion; at present, on the Romanian labour market we find passive policies, concretised in financial aids paid to the unemployed, along with active policies, constituting the most efficient social protection activity addressed to the unemployed (they aim at counterbalancing the inefficiencies determined by the granting of financial allowances, help population to find a job by actions of information, professional training and contributing to the encouragement of the labour force mobility. The paper refers to some theoretical considerations related to the influence factors of employment stimulation, as well as to the unemployment – correlated adequate measures synapse. The applied research comprises the analysis of statistic documents; the method used is the case study, i.e. the activity of employment stimulation carried on by the County Agency for Employment Caraş-Severin, in the period 2004-2012. The conclusions highlight the impact of the activity of the institutions involved in the system of social protection and security within the labour market.

  8. Optical switching by stimulated thermal Rayleigh scattering

    Science.gov (United States)

    Peterson, Lauren M.

    1986-06-01

    Preliminary experiments were conducted whose ultimate goal is to develop all-optical control functions useful in an all-optical or optical-electronic hybrid digital computer or for optical interconnects. Stimulated thermal Rayleigh scattering (STRS) based upon generator experiments was pursued for scattering angles of 90 deg and 180 deg (backscattering). A pulsed nitrogen laser pumped dye laser served as the radiation source and the interaction medium was a liquid to which an absorbing dye was added. STRS amplifier experiments were successful and gain was observed and studied parametrically using eosine dye in ethanol. The gain was found to increase (although the gain coefficient decreased) with increasing pump power and the gain was found to be a maximum at an absorption coefficient of about 2.6 per cm. The generator experiments did not lead to stimulated scattering due to the limited output power of the laser and its multi-longitudinal spectral mode content. These studies will be continued along with analytical modeling in order to characterize the interaction and to enable the optimization of the scattering process.

  9. Suppression and facilitation of auditory neurons through coordinated acoustic and midbrain stimulation: investigating a deep brain stimulator for tinnitus

    Science.gov (United States)

    Offutt, Sarah J.; Ryan, Kellie J.; Konop, Alexander E.; Lim, Hubert H.

    2014-12-01

    Objective. The inferior colliculus (IC) is the primary processing center of auditory information in the midbrain and is one site of tinnitus-related activity. One potential option for suppressing the tinnitus percept is through deep brain stimulation via the auditory midbrain implant (AMI), which is designed for hearing restoration and is already being implanted in deaf patients who also have tinnitus. However, to assess the feasibility of AMI stimulation for tinnitus treatment we first need to characterize the functional connectivity within the IC. Previous studies have suggested modulatory projections from the dorsal cortex of the IC (ICD) to the central nucleus of the IC (ICC), though the functional properties of these projections need to be determined. Approach. In this study, we investigated the effects of electrical stimulation of the ICD on acoustic-driven activity within the ICC in ketamine-anesthetized guinea pigs. Main Results. We observed ICD stimulation induces both suppressive and facilitatory changes across ICC that can occur immediately during stimulation and remain after stimulation. Additionally, ICD stimulation paired with broadband noise stimulation at a specific delay can induce greater suppressive than facilitatory effects, especially when stimulating in more rostral and medial ICD locations. Significance. These findings demonstrate that ICD stimulation can induce specific types of plastic changes in ICC activity, which may be relevant for treating tinnitus. By using the AMI with electrode sites positioned with the ICD and the ICC, the modulatory effects of ICD stimulation can be tested directly in tinnitus patients.

  10. Cardiac responses of vagus nerve stimulation: Intraoperative bradycardia and subsequent chronic stimulation

    NARCIS (Netherlands)

    Ardesch, J.J.; Buschman, H.P.J.; Burgh, van der P.H.; Wagener-Schimmel, L.J.; Aa, van der H.E.; Hageman, G.

    2007-01-01

    OBJECTIVES: Few adverse events on heart rate have been reported with vagus nerve stimulation (VNS) for refractory epilepsy. We describe three cases with intraoperative bradycardia during device testing. PATIENTS AND METHODS: At our hospital 111 patients have received a VNS system. Intraoperative dev

  11. Physical principles of artificial stimulation of the heart : Stimulation of the canine heart in situ

    NARCIS (Netherlands)

    Schneider, H.

    1964-01-01

    1. 1. In artificial heart stimulation, the essential quantity is the density of current, , in the intramyocardial wall. Dosage of the pulse amplitude in volts can have serious consequences for the patient. Curve indications in volts on pacemakers and in publications and records must, therefore, be r

  12. Concerning infrared-stimulated luminescence from K-feldspars: evidence from heating before stimulating

    CERN Document Server

    Galloway, R B

    1999-01-01

    Repeated heating and stimulation by infrared of feldspar samples causes a reduction in the luminescence signal. Two feldspars were investigated, one microcline and one orthoclase. Empirically the fraction of luminescence signal f(n) remaining after the nth cycle of heating and stimulation is given by f(n)=1-a ln(n) for laboratory dosed samples of both microcline and orthoclase feldspars, for heating temperatures of 150 deg. C, 180 deg. C and 220 deg. C, for heating durations per cycle ranging from 20 s to 2400 s and with the study covering 10 cycles of heating and stimulation. Logarithmic decay of luminescence with time has been explained previously, in other contexts, as due either to quantum tunnelling or to a continuous distribution of states being involved but it is shown that these explanations do not fit the present data. The measured data on f(n) were corrected for the loss of luminescence due to infrared stimulation to ensure that this did not account for the differences between the data and the expec...

  13. Electrical stimulation of the upper extremity in stroke: cyclic versus EMG-triggered stimulation

    NARCIS (Netherlands)

    Kroon, de Joke R.; IJzerman, Maarten J.

    2008-01-01

    Objective: To compare the effect of cyclic and electromyography (EMG)-triggered electrical stimulation on motor impairment and function of the affected upper extremity in chronic stroke. Design: Randomized controlled trial. Setting: Outpatient clinic of a rehabilitation centre. Subjects and inte

  14. Determination of stimulation focality in heterogeneous head models during transcranial magnetic stimulation (TMS)

    Science.gov (United States)

    Lee, Erik; Hadimani, Ravi; Jiles, David

    2015-03-01

    Transcranial Magnetic Stimulation (TMS) is an increasingly popular tool used by both the scientific and medical community to understand and treat the brain. TMS has the potential to help people with a wide range of diseases such as Parkinson's, Alzheimer's, and PTSD, while currently being used to treat people with chronic, drug-resistant depression. Through computer simulations, we are able to see the electric field that TMS induces in anatomical human models, but there is no measure to quantify this electric field in a way that relates to a specific patient undergoing TMS therapy. We propose a way to quantify the focality of the induced electric field in a heterogeneous head model during TMS by relating the surface area of the brain being stimulated to the total volume of the brain being stimulated. This figure would be obtained by conducting finite element analysis (FEA) simulations of TMS therapy on a patient specific head model. Using this figure to assist in TMS therapy will allow clinicians and researchers to more accurately stimulate the desired region of a patient's brain and be more equipped to do comparative studies on the effects of TMS across different patients. This work was funded by the Carver Charitable Trust.

  15. A new brain stimulation method: Noninvasive transcranial magneto-acoustical stimulation

    Science.gov (United States)

    Yuan, Yi; Chen, Yu-Dong; Li, Xiao-Li

    2016-08-01

    We investigate transcranial magneto-acoustical stimulation (TMAS) for noninvasive brain neuromodulation in vivo. TMAS as a novel technique uses an ultrasound wave to induce an electric current in the brain tissue in the static magnetic field. It has the advantage of high spatial resolution and penetration depth. The mechanism of TMAS onto a neuron is analyzed by combining the TMAS principle and Hodgkin-Huxley neuron model. The anesthetized rats are stimulated by TMAS, resulting in the local field potentials which are recorded and analyzed. The simulation results show that TMAS can induce neuronal action potential. The experimental results indicate that TMAS can not only increase the amplitude of local field potentials but also enhance the effect of focused ultrasound stimulation on the neuromodulation. In summary, TMAS can accomplish brain neuromodulation, suggesting a potentially powerful noninvasive stimulation method to interfere with brain rhythms for diagnostic and therapeutic purposes. Project supported by the National Natural Science Foundation of China (Grant Nos. 61503321 and 61273063) and the Natural Science Foundation of Hebei Province, China (Grant No. F2014203161).

  16. Cardiac responses of vagus nerve stimulation: Intraoperative bradycardia and subsequent chronic stimulation

    NARCIS (Netherlands)

    Ardesch, J.J.; Buschman, H.P.J.; van der Burgh, P.H.; Wagener-Schimmel, L.J.; van der Aa, H.E.; Hageman, G.

    OBJECTIVES: Few adverse events on heart rate have been reported with vagus nerve stimulation (VNS) for refractory epilepsy. We describe three cases with intraoperative bradycardia during device testing. PATIENTS AND METHODS: At our hospital 111 patients have received a VNS system. Intraoperative

  17. Rabbits immunized with thyroid-stimulating hormone produce autoantiidiotypic thyroid-stimulating antibodies.

    Science.gov (United States)

    Beall, G N; Rapoport, B; Chopra, I J; Kruger, S R

    1985-05-01

    We immunized rabbits with thyroid-stimulating hormone (TSH) to investigate the hypothesis that such immunization could result in production of thyroid-stimulating autoantiidiotypic antibodies to anti-TSH. Thyroid-stimulating immunoglobulin (TSI) appeared in the serum of several rabbits after immunization. At 160 d, TSI equivalent to 6-18 microU TSH/1.5 mg IgG was present in two of six human (h)TSH-, two of six hTSH beta chain-, and two of the four surviving bovine (b)TSH-immunized animals. Control (human serum albumin-immunized rabbits) serum TSI was 4.3 +/- 0.4 (mean +/- SD) at this time. Antiidiotypic antibodies that could bind to monoclonal anti-hTSH were found in the sera of the bTSH-immunized rabbits. The peak TSI activity occurred 3 mo after a TSH booster immunization and declined gradually during subsequent weeks. Evidence that antiidiotypic antibodies to anti-TSH can cause thyroid stimulation strengthens the notion that such antibodies may be the cause of Graves' hyperthyroidism.

  18. 3D-printed wearable backpack stimulator for chronic in vivo aquatic stimulation.

    Science.gov (United States)

    Unguez, Graciela; Duran, Craig; Valles-Rosales, Delia; Harris, Michael; Salazar, Evan; McDowell, Michael; Tang, Wei

    2015-08-01

    The neural mechanisms underlying changes in gene expression in the interconversion between skeletal muscle and the non-contractile electrogenic cells of the electric organ in electric fishes require several days to be manifested. It is extremely challenging to study these non-immediate forms of plasticity in reduced preparations in cell culture due to the time requirements. To address this experimental obstacle we developed a 3D-printed wearable backpack that allows chronic electrical stimulation of aquatic teleost fish. The backpack holds a biphasic simulator using a full H-bridge driver structure. Stimulation amplitude is adjusted with a current source controlled by a micro potentiometer whereas the stimulation waveform is reconfigurable through a micro-controller. A 3.7 V Lithium Ion Polymer battery powers the entire circuit. This backpack system will allow underwater chronic stimulation experiments aimed to study the role that neuronal input exerts on cell phenotypes in a vertebrate species with high tissue regeneration and cell trans-differentiation capabilities.

  19. Discrimination Threshold of Tactile Sense to Point Stimulation and Vector Stimulation in Modulated Vibration by ERP

    Science.gov (United States)

    Mizuno, Tota; Nozawa, Akio; Uchida, Masafumi; Ide, Hideto

    In this paper, we research what kind of influence with the discrimination threshold in frequency area Ts-1 vs. Tl-1 by using segment which had an aim as simple line drawing figure in other words, vector stimulation. As a result, it has been suggested that the modulated vibration discrimination doesn't depend variation of vibration frequency.

  20. The inhibitory effects of pudendal nerve stimulation on bladder overactivity in spinal cord injury dogs: is early stimulation necessary?

    Science.gov (United States)

    Chen, Guoqing; Liao, Limin; Dong, Qian; Ju, Yanhe

    2012-01-01

    To determine the inhibitory effects of pudendal nerve stimulation (5 Hz) on bladder overactivity at early and late stages of spinal cord injury in dogs. The study was performed in eight dogs with chronic spinal cord transection at the T9-T10 level. Group 1 (four dogs) underwent electrical stimulation of pudendal nerve one month after spinal cord transection. Group 2 (four dogs) underwent stimulation six months after spinal cord transection. The bladders were removed for histological examination of fibrosis after the stimulation. The bladder capacity and the compliance were significantly increased (p stimulation in group 1, but not in group 2. The nonvoiding contractions were inhibited in both groups by electrical stimulation. Collagen fiber was increased, while elastic fiber was significantly decreased (p stimulation can increase the bladder capacity and compliance only during the early period before the bladder wall becomes fibrosit and can inhibit the nonvoiding contraction during two stages. © 2012 International Neuromodulation Society.

  1. Repetitive transcranial magnetic stimulation and transcranial direct current stimulation in motor rehabilitation after stroke: an update.

    Science.gov (United States)

    Klomjai, W; Lackmy-Vallée, A; Roche, N; Pradat-Diehl, P; Marchand-Pauvert, V; Katz, R

    2015-09-01

    Stroke is a leading cause of adult motor disability. The number of stroke survivors is increasing in industrialized countries, and despite available treatments used in rehabilitation, the recovery of motor functions after stroke is often incomplete. Studies in the 1980s showed that non-invasive brain stimulation (mainly repetitive transcranial magnetic stimulation [rTMS] and transcranial direct current stimulation [tDCS]) could modulate cortical excitability and induce plasticity in healthy humans. These findings have opened the way to the therapeutic use of the 2 techniques for stroke. The mechanisms underlying the cortical effect of rTMS and tDCS differ. This paper summarizes data obtained in healthy subjects and gives a general review of the use of rTMS and tDCS in stroke patients with altered motor functions. From 1988 to 2012, approximately 1400 publications were devoted to the study of non-invasive brain stimulation in humans. However, for stroke patients with limb motor deficit, only 141 publications have been devoted to the effects of rTMS and 132 to those of tDCS. The Cochrane review devoted to the effects of rTMS found 19 randomized controlled trials involving 588 patients, and that devoted to tDCS found 18 randomized controlled trials involving 450 patients. Without doubt, rTMS and tDCS contribute to physiological and pathophysiological studies in motor control. However, despite the increasing number of studies devoted to the possible therapeutic use of non-invasive brain stimulation to improve motor recovery after stroke, further studies will be necessary to specify their use in rehabilitation.

  2. Priming theta-burst repetitive transcranial magnetic stimulation with low- and high-frequency stimulation.

    Science.gov (United States)

    Todd, Gabrielle; Flavel, Stanley C; Ridding, Michael C

    2009-05-01

    Repetitive transcranial magnetic stimulation (rTMS) can be used to study metaplasticity in human motor cortex. The term metaplasticity describes a phenomenon where the prior synaptic history of a pathway can affect the subsequent induction of long-term potentiation or depression. In the current study, we investigated metaplasticity in human motor cortex with the use of inhibitory continuous theta-burst stimulation (cTBS). cTBS involves short bursts of high frequency (50 Hz) rTMS applied every 200 ms for 40 s. In the first series of experiments, cTBS was primed with 10 min of intermittent 2 or 6 Hz rTMS. Subjects (n = 20) received priming stimulation at 70% of active motor threshold or 90% of resting motor threshold. In another series of experiments, cTBS was primed with excitatory intermittent theta-burst stimulation (iTBS). iTBS involves a 2 s train of theta-burst stimulation delivered every 10 s for 190 s. Stimuli were delivered over the first dorsal interosseus motor area.. The effect of cTBS alone and primed cTBS on motor cortical excitability was investigated by recording motor-evoked potentials (MEP) in the first dorsal interosseus following single-pulse TMS. MEP area in the cTBS alone condition was not significantly different from cTBS primed with 2 or 6 Hz rTMS. However, priming cTBS with iTBS suppressed MEP area to a greater extent than in cTBS alone. Our results provide further evidence of metaplasticity in human motor cortex when appropriate priming protocols are employed.

  3. Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording

    Directory of Open Access Journals (Sweden)

    James eDowsett

    2016-03-01

    Full Text Available Transcranial alternating current stimulation (tACS has until now mostly been administered as an alternating sinusoidal wave. Despite modern tACS stimulators being able to deliver alternating current with any arbitrary shape there has been no systematic exploration into the relative benefits of different waveforms. As tACS is a relatively new technique there is a huge parameter space of unexplored possibilities which may prove superior or complimentary to the traditional sinusoidal waveform. Here we begin to address this with an investigation into the effects of sawtooth wave tACS on individual alpha power. Evidence from animal models suggests that the gradient and direction of an electric current should be important factors for the subsequent neural firing rate; we compared positive and negative ramp sawtooth waves to test this. An additional advantage of sawtooth waves is that the resulting artefact in the electroencephalogram (EEG recording is significantly simpler to remove than a sine wave; accordingly we were able to observe alpha oscillations both during and after stimulation.We found that positive ramp sawtooth, but not negative ramp sawtooth, significantly enhanced alpha power during stimulation relative to sham (p<0.01. In addition we tested for an after-effect of both sawtooth and sinusoidal stimulation on alpha power but in this case did not find any significant effect. This preliminary study paves the way for further investigations into the effect of the gradient and direction of the current in tACS which could significantly improve the usefulness of this technique.

  4. Evaluation of various somatosensory stimulations for functional MRI

    Energy Technology Data Exchange (ETDEWEB)

    Hara, Kazushi; Nakasato, Nobukazu; Mizoi, Kazuo; Yoshimoto, Takashi [Tohoku Univ., Sendai (Japan). School of Medicine; Shimizu, Hiroaki

    1997-01-01

    The aim of this functional magnetic resonance imaging (fMRI) study was to test detectability of activated area using various somatosensory stimulations. The following stimulations were performed in normal volunteers: regular or irregular electrical median nerve stimulation (n=5, each), tactile stimulation to the palm and fingers (n=8), pain stimulation to the index finger (n=5) or to the palm and fingers (n=5). fMRI was acquired with a spoiled gradient echo sequence at 1.5 T. Detectability of activated area was the highest when the pain stimulation was applied to the palm and fingers (80%). A successful rate for the tactile stimulation was 25%, and the other stimulations failed to demonstrate any activation. When successful, the highest signal activation on fMRI was seen on a sulcus, which presumably arose from a vein. The sulcus was defined as the central sulcus by somatosensory evoked field using a median nerve stimulation. Our study indicates that the pain stimulation to the palm and fingers may be a choice for the sensory fMRI. (author)

  5. Bladder emptying by intermittent electrical stimulation of the pudendal nerve

    Science.gov (United States)

    Boggs, Joseph W.; Wenzel, Brian J.; Gustafson, Kenneth J.; Grill, Warren M.

    2006-03-01

    Persons with a suprasacral spinal cord injury cannot empty their bladder voluntarily. Bladder emptying can be restored by intermittent electrical stimulation of the sacral nerve roots (SR) to cause bladder contraction. However, this therapy requires sensory nerve transection to prevent dyssynergic contraction of the external urethral sphincter (EUS). Stimulation of the compound pudendal nerve trunk (PN) activates spinal micturition circuitry, leading to a reflex bladder contraction without a reflex EUS contraction. The present study determined if PN stimulation could produce bladder emptying without nerve transection in cats anesthetized with α-chloralose. With all nerves intact, intermittent PN stimulation emptied the bladder (64 ± 14% of initial volume, n = 37 across six cats) more effectively than either distention-evoked micturition (40 ± 19%, p stimulation (25 ± 23%, p nerves innervating the urethral sphincter, intermittent SR stimulation voided 79 ± 17% (n = 12 across three cats), comparable to clinical results obtained with SR stimulation. Voiding via intermittent PN stimulation did not increase after neurotomy (p > 0.10), indicating that PN stimulation was not limited by bladder-sphincter dyssynergia. Intermittent PN stimulation holds promise for restoring bladder emptying following spinal injury without requiring nerve transection.

  6. Safe neuromuscular electrical stimulator designed for the elderly.

    Science.gov (United States)

    Krenn, Matthias; Haller, Michael; Bijak, Manfred; Unger, Ewald; Hofer, Christian; Kern, Helmut; Mayr, Winfried

    2011-03-01

    A stimulator for neuromuscular electrical stimulation (NMES) was designed, especially suiting the requirements of elderly people with reduced cognitive abilities and diminished fine motor skills. The aging of skeletal muscle is characterized by a progressive decline in muscle mass, force, and condition. Muscle training with NMES reduces the degradation process. The discussed system is intended for evoked muscle training of the anterior and posterior thigh. The core of the stimulator is based on a microcontroller with two modular output stages. The system has two charge-balanced biphasic voltage-controlled stimulation channels. Additionally, the evoked myoelectric signal (M-wave) and the myokinematic signal (surface acceleration) are measured. A central controller unit allows using the stimulator as a stand-alone device. To set up the training sequences and to evaluate the compliance data, a personal computer is connected to the stimulator via a universal serial bus. To help elderly people handle the stimulator by themselves, the user interface is kept very simple. For safety reasons, the electrode impedance is monitored during stimulation. A comprehensive compliance management with included measurements of muscle activity and stimulation intensity enables a scientific use of the stimulator in clinical trials.

  7. Beryllium-stimulated apoptosis in macrophage cell lines.

    Science.gov (United States)

    Sawyer, R T; Fadok, V A; Kittle, L A; Maier, L A; Newman, L S

    2000-08-21

    In vitro stimulation of bronchoalveolar lavage cells from patients with chronic beryllium disease (CBD) induces the production of TNF-alpha. We tested the hypothesis that beryllium (Be)-stimulated TNF-alpha might induce apoptosis in mouse and human macrophage cell lines. These cell lines were selected because they produce a range of Be-stimulated TNF-alpha. The mouse macrophage cell line H36.12j produces high levels of Be-stimulated TNF-alpha. The mouse macrophage cell line P388D.1 produces low, constitutive, levels of TNF-alpha and does not up-regulate Be-stimulated TNF-alpha production. The DEOHS-1 human CBD macrophage cell line does not produce constitutive or Be-stimulated TNF-alpha. Apoptosis was determined by microscopic observation of propidium iodide stained fragmented nuclei in unstimulated and BeSO(4)-stimulated macrophage cell lines. BeSO(4) induced apoptosis in all macrophage cell lines tested. Beryllium-stimulated apoptosis was dose-responsive and maximal after 24 h of exposure to 100 microM BeSO(4). In contrast, unstimulated and Al(2)(SO(4))(3)-stimulated macrophage cell lines did not undergo apoptosis. The general caspase inhibitor BD-fmk inhibited Be-stimulated macrophage cell line apoptosis at concentrations above 50 microM. Our data show that Be-stimulated macrophage cell line apoptosis was caspase-dependent and not solely dependent on Be-stimulated TNF-alpha levels. We speculate that the release of Be-antigen from apoptotic macrophages may serve to re-introduce Be material back into the lung microenvironment, make it available for uptake by new macrophages, and thereby amplify Be-stimulated cytokine production, promoting ongoing inflammation and granuloma maintenance in CBD.

  8. Stimulated photon emission from the vacuum

    CERN Document Server

    Karbstein, Felix

    2014-01-01

    We study the effect of stimulated photon emission from the vacuum subjected to strong space-time dependent electromagnetic fields as generated in the focal spot of two counter-propagating, linearly polarized high-intensity laser pulses. The superposition of the two counter-propagating electromagnetic waves results in a standing electromagnetic wave which - in contrast to a single plane wave - is characterized by at least one nonzero electromagnetic field invariant. Focusing on a comparably simple electromagnetic field profile, which should nevertheless capture the essential features of the electromagnetic fields generated in the focal spots of real high-intensity laser beams, we provide estimates for the numbers of emitted photons attainable with present and near future high-intensity laser facilities.

  9. Improved electrode material for deep brain stimulation.

    Science.gov (United States)

    Petrossians, A; Whalen, J J; Weiland, J D

    2016-08-01

    Deep brain stimulation (DBS) devices have been implanted for treatment of basic tremor, Parkinson's disease and dystonia. These devices use electrodes in contact with tissue to deliver electrical pulses to targeted cells, to elicit specific therapeutic responses. In general, the neuromodulation industry has been evolving towards smaller, less invasive electrodes. However, current electrode materials do not support small sizes without severely restricting the stimulus output. Hence, an improved electrode material will benefit present and future DBS systems. In this study, five DBS leads were modified using a cost-effective and materials-efficient process for applying an ultra-low impedance platinum-iridium alloy coating. One DBS lead was used for insertion test and four DBS leads were chronically pulsed for 12 weeks. The platinum-iridium alloy significantly improved the electrical properties of the DBS electrodes and was robust to insertion into brain and to 12 weeks of chronic pulsing.

  10. [Intestinal stimulation in patients with colostomy].

    Science.gov (United States)

    Quesada, Ramón Ruiz

    2011-12-01

    We presented/displayed our experience in the recovery of the evacuator function of the intestine in patients entered in our service with direction diagnoses of Ileo Paralitico or Adinámico (Functional), that by some cause has been taken part surgically and is carrying of a temporary or permanent colostomia. Our experience is based on more than 10 patients, but we have only gathered the data of ten clinical histories. This stimulation we have obtained it, introducing a sounding Foley type through estoma, trying not to produce to the patient the minimum annoyance to him. We have looked for justification, as much physiological as anatomical, that it entails this answer of recovery of the intestinal peristaltismo, using body solid and not liquid, with idea that thus we respected better the normal intestinal operation in these patients, that already has it altered, to the being carrying of a colostomia.

  11. Pressure Stimulated Currents (PSCin marble samples

    Directory of Open Access Journals (Sweden)

    F. Vallianatos

    2004-06-01

    Full Text Available The electrical behaviour of marble samples from Penteli Mountain was studied while they were subjected to uniaxial stress. The application of consecutive impulsive variations of uniaxial stress to thirty connatural samples produced Pressure Stimulated Currents (PSC. The linear relationship between the recorded PSC and the applied variation rate was investigated. The main results are the following: as far as the samples were under pressure corresponding to their elastic region, the maximum PSC value obeyed a linear law with respect to pressure variation. In the plastic region deviations were observed which were due to variations of Young s modulus. Furthermore, a special burst form of PSC recordings during failure is presented. The latter is emitted when irregular longitudinal splitting is observed during failure.

  12. [Muscular strength development by electromagnetic stimulation].

    Science.gov (United States)

    Gorodnichev, R M; Beliaev, A G; Pivovarova, E A; Shliakhtov, V N

    2014-01-01

    A new tool for muscular strength development by electromagnetic stimulation (MS) of muscular during voluntary contraction has been described. 18 healthy subjects (men) took part in the research. They were devided into two groups--control (CG) and experimental (EG). Subjects of CG and EG have equal muscular strength parameters. M. gastrocnemius of subjects in EG was exposed to MS (1.8 T, 5 Hz) during training exercises (plantar foot flection). The subjects of CG did not receive MS. The torque of plantar foot flection of EG subjects increased significantly (24%) during 10 days training. The torque of plantar foot flection of CG subjects did not change significantly. We hypothesize increasing of muscular strength of EG subjects was result of high-threshold motor units activation under MS.

  13. Electrical stimulation systems for cardiac tissue engineering.

    Science.gov (United States)

    Tandon, Nina; Cannizzaro, Christopher; Chao, Pen-Hsiu Grace; Maidhof, Robert; Marsano, Anna; Au, Hoi Ting Heidi; Radisic, Milica; Vunjak-Novakovic, Gordana

    2009-01-01

    We describe a protocol for tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cells with the application of pulsatile electrical fields designed to mimic those present in the native heart. Tissue culture is conducted in a customized chamber built to allow for cultivation of (i) engineered three-dimensional (3D) cardiac tissue constructs, (ii) cell monolayers on flat substrates or (iii) cells on patterned substrates. This also allows for analysis of the individual and interactive effects of pulsatile electrical field stimulation and substrate topography on cell differentiation and assembly. The protocol is designed to allow for delivery of predictable electrical field stimuli to cells, monitoring environmental parameters, and assessment of cell and tissue responses. The duration of the protocol is 5 d for two-dimensional cultures and 10 d for 3D cultures.

  14. Chemical Stimulation of Engineered Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Peter, E.

    2008-08-08

    The objective of this project is to design, develop and demonstrate methods for the chemical stimulation of candidate EGS reservoirs as well as the chemical treatment of mineral-scaled wellbores. First, a set of candidate chemical compounds capable of dissolving calcite was identified. A series of tests was then performed on each candidate in order to screen it for thermal stability and reactivity towards calcite. A detailed analysis was then performed on each compound that emerged from the screening tests in order to characterize its decay kinetics and reaction kinetics as functions of temperature and chemical composition. From among the compounds emerging from the laboratory studies, one compounds was chosen for a field experiment in order to verify the laboratory predictions.

  15. Acupuncture stimulation induces neurogenesis in adult brain.

    Science.gov (United States)

    Nam, Min-Ho; Ahn, Kwang Seok; Choi, Seung-Hoon

    2013-01-01

    The discovery of adult neurogenesis was a turning point in the field of neuroscience. Adult neurogenesis offers an enormous possibility to open a new therapeutic paradigm of neurodegenerative diseases and stroke. Recently, several studies suggested that acupuncture may enhance adult neurogenesis. Acupuncture has long been an important treatment for brain diseases in the East Asia. The scientific mechanisms of acupuncture treatment for the diseases, such as Alzheimer's disease, Parkinson's disease, and stroke, have not been clarified yet; however, the neurogenic effect of acupuncture can be a possible reason. Here, we have reviewed the studies on the effect of stimulation at various acupoints for neurogenesis, such as ST36 and GV20. The suggested mechanisms are also discussed including upregulation of brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor, basic fibroblast growth factor and neuropeptide Y, and activation of the function of primo vascular system.

  16. Deep brain stimulation: from neurology to psychiatry?

    Science.gov (United States)

    Krack, Paul; Hariz, Marwan I; Baunez, Christelle; Guridi, Jorge; Obeso, Jose A

    2010-10-01

    Functional stereotaxy was introduced in the late 1940s to reduce the morbidity of lobotomy in psychiatric disease by using more focal lesions. The advent of neuroleptics led to a drastic decline in psychosurgery for several decades. Functional stereotactic neurosurgery has recently been revitalized, starting with treatment of Parkinson's disease, in which deep brain stimulation (DBS) facilitates reversible focal neuromodulation of altered basal ganglia circuits. DBS is now being extended to treatment of neuropsychiatric conditions such as Gilles de la Tourette syndrome, obsessive-compulsive disorder, depression and addiction. In this review, we discuss the concept that dysfunction of motor, limbic and associative cortico-basal ganglia-thalamocortical loops underlies these various disorders, which might now be amenable to DBS treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Temperature gradient driven lasing and stimulated cooling

    CERN Document Server

    Sandner, K

    2012-01-01

    A laser can be understood as thermodynamic engine converting heat to a coherent single mode field close to Carnot efficiency. From this perspective spectral shaping of the excitation light generates a higher effective temperature on the pump than on the gain transition. Here, using a toy model of a quantum well structure with two suitably designed tunnel-coupled wells kept at different temperature, we study a laser operated on an actual spatial temperature gradient between pump and gain region. We predict gain and narrow band laser emission for a sufficient temperature gradient and resonator quality. Lasing appears concurrent with amplified heat flow and points to a new form of stimulated solid state cooling. Such a mechanism could raise the operating temperature limit of quantum cascade lasers by substituting phonon emission driven injection, which generates intrinsic heat, by an extended model with phonon absorption steps.

  18. Tactile stimulation can suppress visual perception.

    Science.gov (United States)

    Ide, Masakazu; Hidaka, Souta

    2013-12-13

    An input (e.g., airplane takeoff sound) to a sensory modality can suppress the percept of another input (e.g., talking voices of neighbors) of the same modality. This perceptual suppression effect is evidence that neural responses to different inputs closely interact with each other in the brain. While recent studies suggest that close interactions also occur across sensory modalities, crossmodal perceptual suppression effect has not yet been reported. Here, we demonstrate that tactile stimulation can suppress the percept of visual stimuli: Visual orientation discrimination performance was degraded when a tactile vibration was applied to the observer's index finger of hands. We also demonstrated that this tactile suppression effect on visual perception occurred primarily when the tactile and visual information were spatially and temporally consistent. The current findings would indicate that neural signals could closely and directly interact with each other, sufficient to induce the perceptual suppression effect, even across sensory modalities.

  19. Performance Validity in Deep Brain Stimulation Candidates.

    Science.gov (United States)

    Rossetti, Maria A; Collins, Robert L; York, Michele K

    2017-09-18

    Effort and motivation are important factors that influence performance on neuropsychological tests. Performance validity tests (PVT) have not been investigated in a sample of individuals who are at risk for cognitive decline and are presumably highly motivated to do well. The aim of the current study is to investigate performance validity in individuals with Parkinson's disease and essential tremor who are being considered for deep brain stimulation (DBS) surgery. Thirty DBS surgical candidates underwent neuropsychological evaluation including completion of the Word Memory Test (WMT) as well as embedded PVTs. Sixteen DBS candidates (53.3%) obtained a passing WMT score, 11 patients (36.6%) obtained scores in the "caution" range, and three patients (10%) produced failing scores. None of the patients scored below an 82.5% on the first three WMT subtests. This pilot study is the first to describe PVT in DBS candidates and in a presumed highly motivated, older, and cognitively at-risk sample.

  20. Emdogain stimulates matrix degradation by osteoblasts.

    Science.gov (United States)

    Goda, S; Inoue, H; Kaneshita, Y; Nagano, Y; Ikeo, T; Ikeo, Y T; Iida, J; Domae, N

    2008-08-01

    Emdogain has been used clinically for periodontal regeneration, although the underlying molecular mechanisms are not clear at present. In this study, we hypothesized that Emdogain stimulated degradation of type I collagen via osteoblasts. We showed that Emdogain enhanced cell-mediated degradation of type I collagen in an MMP-dependent manner. Although MG-63 cells spontaneously produced a zymogen form of MMP-1, treatment with Emdogain significantly induced the generation of the active form of this enzyme. We demonstrated that MMP-3 was produced from MG63 cells in response to Emdogain in a MEK1/2-dependent manner. Concomitantly, blocking of MEK1/2 activation by U0126 significantly inhibited the generation of the active form of MMP-1 without affecting the total production of this collagenase. These results suggest that Emdogain facilitates tissue regeneration through the activation of the collagenase, MMP-1, that degrades matrix proteins in bone tissue microenvironments.

  1. Orbital surveys of solar stimulated luminescence

    Science.gov (United States)

    Hemphill, W. R.; Theisen, A. F.; Tyson, R. M.; Granata, J. S.

    The Fraunhofer line discriminator (FLD) is an electro-optical device for imaging natural and manmade materials which have been stimulated to luminesce by the sun. An airborne FLD has been used to detect geochemically stressed vegetation, drought-stressed agricultural crops, industrial and residential pollution effluents, marine oil seeps, phosphate rock, uranium-bearing sandstone, and bioluminescent ocean plankton. Three-dimensional perspective plots of excitation and emission spectra, measured with a laboratory spectrometer, graphically depict similarities and differences in luminescence properties between sample materials. The laboratory data also include luminescence intensities at six Fraunhofer lines in the visible and near-infrared regions of the electromagnetic spectrum. Both the airborne and laboratory data suggest the feasibility of delineating and monitoring at least some of these luminescing materials from orbital altitude, such as a test flight aboard the Space Shuttle using an improved third-generation FLD.

  2. Studying barrier-discharge-stimulated plasmachemical reactions

    Science.gov (United States)

    Malanichev, V. E.; Malashin, M. V.; Moshkunov, S. I.; Nebogatkin, S. V.; Khomich, V. Yu.; Shmelev, V. M.

    2017-05-01

    Barrier-discharge stimulation of chemical reactions has been studied in the case of methane oxidation by atmospheric oxygen with the formation of carbon monoxide and hydrogen. Experiments in a plasmachemical reactor demonstrated the possibility of increasing the yield of synthesis gas (syngas) by means of plasma pretreatment of the initial mixture of air and methane in a 7: 1 ratio at atmospheric pressure. The output-gas composition was determined by gas chromatography. It is established that the plasma-discharge treatment of the initial gas mixture leads to a 15% increase in the amount of syngas at the reactor output and increases the reaction selectivity with respect to hydrogen and carbon monoxide by 3.2 and 6.5%, respectively.

  3. Ozone as a stimulant for fungus sporulation

    Energy Technology Data Exchange (ETDEWEB)

    Richards, M.C.

    1949-01-01

    Ozone is generally considered to be a fungicide and is used in meat storage plants to retard the development of fungi. It has been used experimentally in apple storages for similar reasons. Certain fungi which produced few or no spores in culture when exposed to ozone produced spores abundantly. Sporulation was increased with Alternaria solani and Alternaria oleraccae with no impairment of germination. A third species of Alternaria, which did not produce spores normally in culture, produced numerous spores when growing cultures were exposed to ozone. Ninety-six per cent of the spores germinated. The squash black rot pathogen, Mycospherella citrullina, produces few or no pyenidia nor spores on potato-dextrose agar. When cultures are exposed to ozone, masses of spores are produced none of which will germinate. Ozone will stimulate fungi to sporulate. With certain fungi, however, ozone appears to be toxic to the spores.

  4. Nanoparticles: a challenging vehicle for neural stimulation

    Directory of Open Access Journals (Sweden)

    Elisabetta eColombo

    2016-03-01

    Full Text Available Neurostimulation represents a powerful and well-established tool for the treatment of several diseases affecting the central nervous system. Although effective in reducing the symptoms or the progression of brain disorders, the poor accessibility of the deepest areas of the brain currently hampers the possibility of a more specific and controlled therapeutic stimulation, depending on invasive surgical approaches and long-term stability and biocompatibility issues. The massive research of the last decades on nanomaterials and nanoscale devices favored the development of new tools to address the limitations of the available neurostimulation approaches. This mini-review focuses on the employment of nanoparticles for the modulation of the electrophysiological activity of neuronal networks and the related transduction mechanisms underlying the nanostructure-neuron interfaces.

  5. Stimulated Raman backscattering at high laser intensities

    Energy Technology Data Exchange (ETDEWEB)

    Skoric, M.M. [Vinca Inst. of Nuclear Sciences, Belgrade (Yugoslavia); Tajima, Toshiki; Sasaki, Akira; Maluckov, A.; Jovanovic, M.

    1998-03-01

    Signatures of Stimulated Raman backscattering of a short-pulse high-intensity laser interacting with an underdense plasma are discussed. We introduce a nonlinear three-wave interaction model that accounts for laser pump depletion and relativistic detuning. A mechanism is revealed based on a generic route to chaos, that predicts a progressive increase of the backscatter complexity with a growing laser intensity. Importance of kinetic effects is outlined and demonstrated in fluid-hybrid and particle simulations. As an application, we show that spectral anomalies of the backscatter, predicted by the above model, are consistent with recent sub-picosecond, high-intensity laser gas-target measurements at Livermore and elsewhere. Finally, a recently proposed scheme for generation of ultra-short, low-prepulse laser pulses by Raman backscattering in a thin foil target, is shown. (author)

  6. Employees' Stimulation for the Perception of Innovations

    Directory of Open Access Journals (Sweden)

    Tаtiana V. Peregudova

    2013-01-01

    Full Text Available The article justifies the approach to the encouragement of employees of the organization to the perception of innovative activity products. At the core of this process there is an estimation of their activity regarding contribution to this process by group examination with point scoring of each employee on the selected criteria.The principles of formation and distribution of the bonus fund, which it is proposed to establish on the basis of proportion of the sum of average scores which the employee received in total, are given. 20% of employees with the low rates are not paid the bonus.Such approach to the stimulation of innovation implementation in the organization will create a positive institutional environment and reduce implementation time.

  7. Transcranial magnetic stimulation (TMS) inhibits cortical dendrites.

    Science.gov (United States)

    Murphy, Sean C; Palmer, Lucy M; Nyffeler, Thomas; Müri, René M; Larkum, Matthew E

    2016-03-18

    One of the leading approaches to non-invasively treat a variety of brain disorders is transcranial magnetic stimulation (TMS). However, despite its clinical prevalence, very little is known about the action of TMS at the cellular level let alone what effect it might have at the subcellular level (e.g. dendrites). Here, we examine the effect of single-pulse TMS on dendritic activity in layer 5 pyramidal neurons of the somatosensory cortex using an optical fiber imaging approach. We find that TMS causes GABAB-mediated inhibition of sensory-evoked dendritic Ca(2+) activity. We conclude that TMS directly activates fibers within the upper cortical layers that leads to the activation of dendrite-targeting inhibitory neurons which in turn suppress dendritic Ca(2+) activity. This result implies a specificity of TMS at the dendritic level that could in principle be exploited for investigating these structures non-invasively.

  8. Caloric vestibular stimulation in aphasic syndrome

    Directory of Open Access Journals (Sweden)

    David eWilkinson

    2013-12-01

    Full Text Available Caloric vestibular stimulation (CVS is commonly used to diagnose brainstem disorder but its therapeutic application is much less established. Based on the finding that CVS increases blood flow to brain structures associated with language and communication, we assessed whether the procedure has potential to relieve symptoms of post-stroke aphasia. Three participants, each presenting with chronic, unilateral lesions to the left hemisphere, were administered daily CVS for 4 consecutive weeks. Relative to their pre-treatment baseline scores, two of the three participants showed significant improvement on both picture and responsive naming at immediate and one-week follow-up. One of these participants also showed improved sentence repetition, and another showed improved auditory word discrimination. No adverse reactions were reported. These data provide the first, albeit tentative, evidence that CVS may relieve expressive and receptive symptoms of aphasia. A larger, sham-controlled study is now needed to further assess efficacy.

  9. Luminescent solar concentrator improvement by stimulated emission

    Science.gov (United States)

    Kaysir, Md Rejvi; Fleming, Simon; MacQueen, Rowan W.; Schmidt, Timothy W.; Argyros, Alexander

    2015-12-01

    Luminescent solar concentrators (LSCs) offer the prospect of reducing the cost of solar energy, and are a promising candidate for building integrated photovoltaic (PV) structures. However, the realization of commercially viable efficiency of LSCs is currently hindered by reabsorption losses. In this work, a method is introduced for reducing reabsorption as well as improving directional emission in LSCs by using stimulated emission. Light from a seed laser (potentially an inexpensive laser diode) passes through the entire length of the LSC panel, modifying the emission spectrum of excited dye molecules such that it is spectrally narrower, at wavelengths that minimize reabsorption, and directed by the seed laser towards a small target PV cell. A mathematical model of such a system is presented which identifies different physical parameters responsible for the power conversion efficiency and gives the net effective output power.

  10. Luminescent solar concentrators utilizing stimulated emission.

    Science.gov (United States)

    Kaysir, Md Rejvi; Fleming, Simon; MacQueen, Rowan W; Schmidt, Timothy W; Argyros, Alexander

    2016-03-21

    Luminescent solar concentrators (LSCs) are an emerging technology that aims primarily to reduce the cost of solar energy, with great potential for building integrated photovoltaic (PV) structures. However, realizing LSCs with commercially viable efficiency is currently hindered by reabsorption losses. Here, we introduce an approach to reducing reabsorption as well as improving directional emission in LSCs by using stimulated emission. Light from a seed laser (potentially an inexpensive laser diode) passes through the entire area of the LSC panel, modifying the emission spectrum of excited dye molecules such that it is spectrally narrower, at wavelengths that minimize reabsorption to allow net gain in the system, and directed towards a small PV cell. A mathematical model, taking into account thermodynamic considerations, of such a system is presented which identifies key parameters and allows evaluation in terms of net effective output power.

  11. Wireless distributed functional electrical stimulation system

    Directory of Open Access Journals (Sweden)

    Jovičić Nenad S

    2012-08-01

    Full Text Available Abstract Background The control of movement in humans is hierarchical and distributed and uses feedback. An assistive system could be best integrated into the therapy of a human with a central nervous system lesion if the system is controlled in a similar manner. Here, we present a novel wireless architecture and routing protocol for a distributed functional electrical stimulation system that enables control of movement. Methods The new system comprises a set of miniature battery-powered devices with stimulating and sensing functionality mounted on the body of the subject. The devices communicate wirelessly with one coordinator device, which is connected to a host computer. The control algorithm runs on the computer in open- or closed-loop form. A prototype of the system was designed using commercial, off-the-shelf components. The propagation characteristics of electromagnetic waves and the distributed nature of the system were considered during the development of a two-hop routing protocol, which was implemented in the prototype’s software. Results The outcomes of this research include a novel system architecture and routing protocol and a functional prototype based on commercial, off-the-shelf components. A proof-of-concept study was performed on a hemiplegic subject with paresis of the right arm. The subject was tasked with generating a fully functional palmar grasp (closing of the fingers. One node was used to provide this movement, while a second node controlled the activation of extensor muscles to eliminate undesired wrist flexion. The system was tested with the open- and closed-loop control algorithms. Conclusions The system fulfilled technical and application requirements. The novel communication protocol enabled reliable real-time use of the system in both closed- and open-loop forms. The testing on a patient showed that the multi-node system could operate effectively to generate functional movement.

  12. Dendritic Cells Stimulated by Cationic Liposomes.

    Science.gov (United States)

    Vitor, Micaela Tamara; Bergami-Santos, Patrícia Cruz; Cruz, Karen Steponavicius Piedade; Pinho, Mariana Pereira; Barbuto, José Alexandre Marzagão; De La Torre, Lucimara Gaziola

    2016-01-01

    Immunotherapy of cancer aims to harness the immune system to detect and destroy cancer cells. To induce an immune response against cancer, activated dendritic cells (DCs) must present tumor antigens to T lymphocytes of patients. However, cancer patients' DCs are frequently defective, therefore, they are prone to induce rather tolerance than immune responses. In this context, loading tumor antigens into DCs and, at the same time, activating these cells, is a tempting goal within the field. Thus, we investigated the effects of cationic liposomes on the DCs differentiation/maturation, evaluating their surface phenotype and ability to stimulate T lymphocytes proliferation in vitro. The cationic liposomes composed by egg phosphatidylcholine, 1,2-dioleoyl-3-trimethylammonium propane and 1,2-dioleoylphosphatidylethanolamine (50/25/25% molar) were prepared by the thin film method followed by extrusion (65 nm, polydispersity of 0.13) and by the dehydration-rehydration method (95% of the population 107 nm, polydispersity of 0.52). The phenotypic analysis of dendritic cells and the analysis of T lymphocyte proliferation were performed by flow cytometry and showed that both cationic liposomes were incorporated and activated dendritic cells. Extruded liposomes were better incorporated and induced higher CD86 expression for dendritic cells than dehydrated-rehydrated vesicles. Furthermore, dendritic cells which internalized extruded liposomes also provided stronger T lymphocyte stimulation. Thus, cationic liposomes with a smaller size and polydispersity seem to be better incorporated by dendritic cells. Hence, these cationic liposomes could be used as a potential tool in further cancer immunotherapy strategies and contribute to new strategies in immunotherapy.

  13. Using fetal acoustic stimulation to shorten the biophysical profile.

    Science.gov (United States)

    Pinette, Michael G; Blackstone, Jacquelyn; Wax, Joseph R; Cartin, Angelina

    2005-06-01

    To determine whether fetal acoustic stimulation can decrease the time required to achieve a reassuring biophysical profile. Patients scheduled for a biophysical profile were prospectively assigned to study and control groups. The study group received 3 seconds of acoustic stimulation if fetal breathing, tone, or movement were not present during the first 5 minutes of the study. The biophysical profile was completed in the standard fashion, for both groups. A total of 870 patients were enrolled (458 control, 412 with stimulation). The fetal acoustic stimulation group had decreased testing time (3 minutes) and fewer non-reassuring tests (5%). The fetal acoustic stimulation group had fewer studies without breathing, potentially reducing the need for further testing or intervention. Fetal acoustic stimulation can be used to decrease the biophysical profile testing time and to reduce the number of non-reassuring tests. (c) 2005 Wiley Periodicals, Inc. J Clin Ultrasound 33:223-225, 2005.

  14. [Pituitary hormone secretion induced by optokinetic stimulation (author's transl)].

    Science.gov (United States)

    Mang, W L; Scherer, H; Eversmann, T; Gottsmann, M

    1978-08-01

    A slight optokinetic stimulation induces a significant increase of serum levels of antidiuretic hormone 1,1 +/- 0.8 pg/ml (mean +/- SD) to 3,3 +/- 1,9 pg/ml (mean +/- SD). Serum levels of gGH and cortisol remain unchanged, whereas serum prolactin levels decrease slightly. The ADH secretion seems to be the most sensitive hormonal parameter of the stimulation of the vestibular nuclei induced either by the optokinetic stimulation or by the Coriolis effect.

  15. Improved Discrimination of Visual Stimuli Following Repetitive Transcranial Magnetic Stimulation

    OpenAIRE

    Waterston, Michael L.; Pack, Christopher C.

    2010-01-01

    BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) at certain frequencies increases thresholds for motor-evoked potentials and phosphenes following stimulation of cortex. Consequently rTMS is often assumed to introduce a "virtual lesion" in stimulated brain regions, with correspondingly diminished behavioral performance. METHODOLOGY/PRINCIPAL FINDINGS: Here we investigated the effects of rTMS to visual cortex on subjects' ability to perform visual psychophysical tasks. Contrary t...

  16. Modulating Hippocampal Plasticity with In Vivo Brain Stimulation

    Science.gov (United States)

    2015-09-16

    anodal transcranial direct current stimulation in healthy adults of younger and older age. Front Aging Neurosci 6:146. CrossRef Medline Hoy KE...on cognition and performance. 15. SUBJECT TERMS brain stimulation; extracellular recording; hippocampus; long term potentiation; rat; tDCS 16...Prescribed by ANSI Std. Z39.18 Development /Plasticity/Repair Modulating Hippocampal Plasticity with In Vivo Brain Stimulation X Joyce G. Rohan,1,3

  17. Neuroprotective effects of vagus nerve stimulation on traumatic brain injury

    OpenAIRE

    Zhou, Long; Lin, Jinhuang; Lin, Junming; Kui, Guoju; Zhang, Jianhua; Yu, Yigang

    2014-01-01

    Previous studies have shown that vagus nerve stimulation can improve the prognosis of traumatic brain injury. The aim of this study was to elucidate the mechanism of the neuroprotective effects of vagus nerve stimulation in rabbits with brain explosive injury. Rabbits with brain explosive injury received continuous stimulation (10 V, 5 Hz, 5 ms, 20 minutes) of the right cervical vagus nerve. Tumor necrosis factor-α, interleukin-1β and interleukin-10 concentrations were detected in serum and b...

  18. Bio-electromagnetic model of deep brain stimulation

    OpenAIRE

    Walckiers, Grégoire

    2009-01-01

    Functional stimulation is one of the most fascinating applications of bioelectromagnetism. It deals with the stimulation of excitable biological tissues by electromagnetic fields. One of its most impressive medical applications is the subthalamic nucleus deep brain stimulation (DBS). It consists in the insertion of an electrode into the deep brain, delivering electric pulses to treat Parkinson's disease and other movement disorders. But despite its wide use throughout the world for almost twe...

  19. New modalities of brain stimulation for stroke rehabilitation

    OpenAIRE

    Edwardson, M. A.; Lucas, T. H.; Carey, J. R.; Fetz, E. E.

    2012-01-01

    Stroke is a leading cause of disability, and the number of stroke survivors continues to rise. Traditional neurorehabilitation strategies aimed at restoring function to weakened limbs provide only modest benefit. New brain stimulation techniques designed to augment traditional neurorehabilitation hold promise for reducing the burden of stroke-related disability. Investigators discovered that repetitive transcranial magnetic stimulation (rTMS), trans-cranial direct current stimulation (tDCS), ...

  20. Shock Wave-Stimulated Periosteum for Cartilage Repair

    Science.gov (United States)

    2015-03-01

    AD_________________ Award Number: W81XWH-10-1-0914 TITLE: Shock Wave-Stimulated Periosteum for Cartilage Repair PRINCIPAL INVESTIGATOR...30Sep2010 – 1Dec2014 4. TITLE AND SUBTITLE Shock Wave-Stimulated Periosteum for Cartilage Repair 5a. CONTRACT NUMBER W81XWH-10-1-0914 5b. GRANT NUMBER... shock wave (ESW)-stimulated periosteum improves cartilage repair when it is used as an autograft to fill a defect in the articular surface of goats. A

  1. Spatially Patterned Electrical Stimulation to Enhance Resolution of Retinal Prostheses

    OpenAIRE

    2014-01-01

    Retinal prostheses electrically stimulate neurons to produce artificial vision in people blinded by photoreceptor degenerative diseases. The limited spatial resolution of current devices results in indiscriminate stimulation of interleaved cells of different types, precluding veridical reproduction of natural activity patterns in the retinal output. Here we investigate the use of spatial patterns of current injection to increase the spatial resolution of stimulation, using high-density multie...

  2. [Programmable multichannel electrophysiological stimulator based on MCU and CPLD platform].

    Science.gov (United States)

    Zheng, Yi; Wu, Xiao-Mei; Fang, Zu-Xiang

    2008-01-01

    According to the instruction of the operator, the designed programmable multichannel stimulator will deliver stimuli with an assigned amplitude and a proper width to the electrode-array in various modes. Each stimulation time is controlled by the internal timer of the MCU, while the stimulated electrodes' spatial parameter is controlled by the CPLD. Having abandoned conventional isolation using the transformer, we have adapted optical coupling and stable float ground connection to achieve the safety standard required by physiological measurements.

  3. Rhythmic light stimulation modifies brain oscillations via entrainment

    Directory of Open Access Journals (Sweden)

    Annika eNotbohm

    2016-02-01

    Full Text Available The functional relevance of brain oscillations in the alpha frequency range (8-13Hz has been repeatedly investigated through the use of rhythmic visual stimulation. The underlying mechanism of the steady-state visual evoked potential (SSVEP measured in EEG during rhythmic stimulation, however, is not known. There are two hypotheses on the origin of the SSVEPs: entrainment of brain oscillations and superposition of event-related responses (ERPs. The entrainment but not the superposition hypothesis justifies rhythmic visual stimulation as a means to manipulate brain oscillations, because superposition assumes a linear summation of single responses, independent from ongoing brain oscillations. Here, we stimulated participants with a rhythmic flickering light of different frequencies and intensities.. We measured entrainment by comparing the phase coupling of brain oscillations stimulated by rhythmic visual flicker with the oscillations induced by arrhythmic jittered stimulation, varying the time, stimulation frequency, and intensity conditions. In line with a theoretical concept of entrainment (the so called Arnold tongue, we found the phase coupling to be more pronounced with increasing stimulation intensity as well as at stimulation frequencies closer to each participant’s intrinsic frequency. Only inside the Arnold tongue did the conditions significantly differ from the jittered stimulation. Furthermore, even in a single sequence of an SSVEP, we found non-linear features (intermittency of phase locking that contradict the linear summation of single responses, as assumed by the superposition hypothesis. Our findings provide unequivocal evidence that visual rhythmic stimulation entrains brain oscillations, thus validating the approach of rhythmic stimulation as a manipulation of brain oscillations.

  4. Growth hormone does not stimulate early healing in rat tendons

    OpenAIRE

    2012-01-01

    Growth Hormone stimulates bone growth and fracture repair. It acts mainly by increasing the systemic levels of IGF-1. Local treatment with IGF-1 appears to stimulate tendon healing. We therefore hypothesized that systemic treatment with Growth Hormone would also stimulate tendon healing. Rat Achilles tendons were transected and left to heal. 4 groups were studied. Intramuscular injections of botulinum toxin A (Botox) were used to reduce loading in 2 groups. The animals were randomized to twic...

  5. Luminescence from potassium feldspars stimulated by infrared and green light

    DEFF Research Database (Denmark)

    Duller, G.A.T.; Bøtter-Jensen, L.

    1993-01-01

    A series of experiments are reported which investigate stimulated luminescence from potassium feldspar. The aim is to provide a basic phenomenological description of the response of the material to stimulation by heat, infrared radiation (875 DELTA 80 nm) and a green light wavelength band from 5 15...... to 560 nm. Two conclusions are drawn: firstly it is suggested that the majority of the trapped charge responsible for the infrared stimulated luminescence signal does not give rise to a thermoluminescence signal, and secondly that a large traction of the two optically stimulated luminescence signals...

  6. Stimulant use among secondary school students in Osogbo, Nigeria.

    Science.gov (United States)

    Eegunranti, B A; Fatoye, F O; Morakinyo, O

    2009-09-01

    The objectives of this study were to determine the prevalence and pattern of stimulant use and its association with 'brain fag syndrome' among secondary school students in Osogbo, Osun State. The study also aimed to determine the association of socio-demographic variables (of the students and their parents) with stimulant use. A questionnaire consisting of sociodemographic variables, the stimulant use section of the WHO Student Drug Use Questionnaire and the Brain Fag Syndrome Scale (BFSS) was administered on randomly selected students of the two Local Government Areas of Osogbo. The prevalence rates of stimulant use were calculated and the association of stimulant use with Brain Fag Syndrome (BFS) and socio-demographic variables was determined. The 30-day prevalence rate of stimulant use was 20.3%. Users engaged more in the use of common and cheap stimulants (coffee and kola nut). Majority of users started at age 13 years or below. There was a very high relationship between stimulant use and the symptoms of the BFS (pattendance, polygamous background, low education of mother, high education of father and the description of mother as being too permissive. The findings suggest the need to increase the awareness of the dangers of stimulant use among students. Control programmes are urgently needed to prevent student wastage.

  7. A Microfabricated Transduction Coil for Inductive Deep Brain Stimulation

    Directory of Open Access Journals (Sweden)

    Jie (Jayne WU

    2006-07-01

    Full Text Available "Inductively Coupled Deep Brain Stimulator" describes a chip/system design to inductively couple arbitrary waveforms to electrodes embedded in the brain for deep brain stimulation or other neurostimulation. This approach moves the conventionally implanted signal generator outside the body and provides flexibility in adjusting waveforms to investigate optimum stimulation waveforms. An "inlaid electroplating" process with through-wafer plating is used to reduce microcoil resistance and integrate microstructures and electronics. Utilizing inductive link resonance specific to microcoils, waveforms are selectively transmitted to microcoils, which further produces biphasic waveforms that are suitable for deep brain stimulation.

  8. Calibration of clinical cerebellar and deep brain stimulation systems.

    Science.gov (United States)

    McLellan, D L; Wright, G D; Renouf, F

    1981-01-01

    The increasing use of electrical stimulation of the brain for relief of pain, spasticity and epilepsy has introduced unfamiliar techniques into clinical neurological and neurosurgical practice. In view of the evidence that excessive levels of stimulation can damage brain tissue, it is of great importance to monitor the dose of stimulation. A review of recent clinical papers suggests that many centres do not measure the dose accurately, relying on arbitrary dial settings on external transmitters. This paper reviews that factors that affect the dose received by the patient and suggests methods of measuring them, at operation and subsequently, which should routinely be employed by clinicians implanting stimulators. Images PMID:6973614

  9. Design of electrical stimulation bioreactors for cardiac tissue engineering.

    Science.gov (United States)

    Tandon, N; Marsano, A; Cannizzaro, C; Voldman, J; Vunjak-Novakovic, G

    2008-01-01

    Electrical stimulation has been shown to improve functional assembly of cardiomyocytes in vitro for cardiac tissue engineering. Carbon electrodes were found in past studies to have the best current injection characteristics. The goal of this study was to develop rational experimental design principles for the electrodes and stimulation regime, in particular electrode configuration, electrode ageing, and stimulation amplitude. Carbon rod electrodes were compared via electrochemical impedance spectroscopy (EIS) and we identified a safety range of 0 to 8 V/cm by comparing excitation thresholds and maximum capture rates for neonatal rat cardiomyocytes cultured with electrical stimulation. We conclude with recommendations for studies involving carbon electrodes for cardiac tissue engineering.

  10. Stimulation of the retina with a multielectrode extraocular visual prosthesis.

    Science.gov (United States)

    Chowdhury, Vivek; Morley, John W; Coroneo, Minas T

    2005-08-01

    An extraocular approach to developing a retinal prosthesis for blind patients using electrodes placed on the outer surface of the eye is suggested. Experiments were carried out to determine the feasibility of this approach, and evaluate electrode configurations and parameters for stimulation. In anaesthetized cats, a 21-electrode extraocular retinal prosthesis (ERP) array was sutured to the sclera over the lateral surface of the eye. Electrically evoked potentials (EEP) were recorded at the visual cortex bilaterally in response to retinal stimulation with the electrode array. Bipolar stimulation of the ERP array electrodes in horizontal and vertical configurations and at different interelectrode separations was investigated with biphasic constant-current pulses. Electrical stimulation of the lateral retina with an ERP elicited EEP that were higher in the ipsilateral visual cortex. The threshold for bipolar retinal stimulation was 500 microA. EEP amplitude increased with increases in stimulus pulse duration and current intensity. Retinal stimulation was slightly more effective with electrodes in a vertical as opposed to horizontal orientation. A larger interelectrode separation resulted in a higher EEP amplitude. Retinal stimulation with a prototype ERP array is demonstrated. The thresholds for retinal excitation are below safe charge-density limits for chronic neural stimulation. Ipsilateral localization of the EEP suggests that localized retinal stimulation is occurring. An ERP is a new approach to retinal prosthesis research, and might lead to the development of a low-resolution visual prosthesis for blind patients.

  11. Is deep brain stimulation a form of psychosurgery?

    Science.gov (United States)

    Sachdev, Perminder

    2007-04-01

    To examine the potential for the experimental treatment of deep brain stimulation for neuropsychiatric disorders, and to debate the argument that it should be considered another form of psychosurgery. Psychosurgery is an old term with considerable pejorative connotations. It should be replaced with the more descriptive and accurate 'neurosurgery for psychiatric disorders'. Moreover, neurosurgery should reflect ablative neurosurgery, and surgery for brain stimulation should be categorised as brain stimulation rather than neurosurgery, or indeed psychosurgery. This will prevent legislative restrictions on the development of brain stimulation techniques and not tar them with the lobotomy brush.

  12. Direct current electrical stimulation chamber for treating cells in vitro.

    Science.gov (United States)

    Mobini, Sahba; Leppik, Liudmila; Barker, John H

    2016-02-01

    Electrical stimulation has been shown to promote healing and regeneration in skin, bone, muscle, and nerve tissues in clinical studies. Recently, studies applying electrical stimulation to influence cell behavior associated with proliferation, differentiation, and migration have provided a better understanding of the underlying mechanisms of electrical stimulation-based clinical treatments and improved tissue-engineered products through electro-bioreactor technologies. Here, we present a novel device for delivering direct current (DC) electrical stimulation (ES) to cultivated cells in vitro. Our simplified electro-bioreactor is customized for applying DC electrical current simultaneously in six individual tissue culture wells. The design overcomes previous experimental replicate limitations, thus reducing experimental time and cost.

  13. A Systematic Review of Electric-Acoustic Stimulation

    Science.gov (United States)

    Ching, Teresa Y. C.; Cowan, Robert

    2013-01-01

    Cochlear implant systems that combine electric and acoustic stimulation in the same ear are now commercially available and the number of patients using these devices is steadily increasing. In particular, electric-acoustic stimulation is an option for patients with severe, high frequency sensorineural hearing impairment. There have been a range of approaches to combining electric stimulation and acoustic hearing in the same ear. To develop a better understanding of fitting practices for devices that combine electric and acoustic stimulation, we conducted a systematic review addressing three clinical questions: what is the range of acoustic hearing in the implanted ear that can be effectively preserved for an electric-acoustic fitting?; what benefits are provided by combining acoustic stimulation with electric stimulation?; and what clinical fitting practices have been developed for devices that combine electric and acoustic stimulation? A search of the literature was conducted and 27 articles that met the strict evaluation criteria adopted for the review were identified for detailed analysis. The range of auditory thresholds in the implanted ear that can be successfully used for an electric-acoustic application is quite broad. The effectiveness of combined electric and acoustic stimulation as compared with electric stimulation alone was consistently demonstrated, highlighting the potential value of preservation and utilization of low frequency hearing in the implanted ear. However, clinical procedures for best fitting of electric-acoustic devices were varied. This clearly identified a need for further investigation of fitting procedures aimed at maximizing outcomes for recipients of electric-acoustic devices. PMID:23539259

  14. Modulation of auditory percepts by transcutaneous electrical stimulation.

    Science.gov (United States)

    Ueberfuhr, Margarete Anna; Braun, Amalia; Wiegrebe, Lutz; Grothe, Benedikt; Drexl, Markus

    2017-07-01

    Transcutaneous, electrical stimulation with electrodes placed on the mastoid processes represents a specific way to elicit vestibular reflexes in humans without active or passive subject movements, for which the term galvanic vestibular stimulation was coined. It has been suggested that galvanic vestibular stimulation mainly affects the vestibular periphery, but whether vestibular hair cells, vestibular afferents, or a combination of both are excited, is still a matter of debate. Galvanic vestibular stimulation has been in use since the late 18th century, but despite the long-known and well-documented effects on the vestibular system, reports of the effect of electrical stimulation on the adjacent cochlea or the ascending auditory pathway are surprisingly sparse. The present study examines the effect of transcutaneous, electrical stimulation of the human auditory periphery employing evoked and spontaneous otoacoustic emissions and several psychoacoustic measures. In particular, level growth functions of distortion product otoacoustic emissions were recorded during electrical stimulation with alternating currents (2 Hz, 1-4 mA in 1 mA-steps). In addition, the level and frequency of spontaneous otoacoustic emissions were followed before, during, and after electrical stimulation (2 Hz, 1-4 mA). To explore the effect of electrical stimulation on the retrocochlear level (i.e. on the ascending auditory pathway beyond the cochlea), psychoacoustic experiments were carried out. Specifically, participants indicated whether electrical stimulation (4 Hz, 2 and 3 mA) induced amplitude modulations of the perception of a pure tone, and of auditory illusions after presentation of either an intense, low-frequency sound (Bounce tinnitus) or a faint band-stop noise (Zwicker tone). These three psychoacoustic measures revealed significant perceived amplitude modulations during electrical stimulation in the majority of participants. However, no significant changes of evoked and

  15. HGF is released from buccal fibroblasts after smokeless tobacco stimulation

    DEFF Research Database (Denmark)

    Dabelsteen, S; Christensen, S; Gron, B

    2005-01-01

    To investigate the effect of smokeless tobacco (ST) on (1) HGF, KGF and GM-CSF expression by buccal fibroblasts and (2) on keratinocyte and fibroblast proliferation. Buccal fibroblasts were stimulated with different concentrations of ST extracts in a double dilution from 0.50% w/v to 0.03% w...... on exposure time and on concentration of the tobacco extract. High concentration increased production of HGF 4-fold. KGF production was doubled when high concentration of tobacco was used, low concentration did not stimulate cells. GM-CSF production was low in both stimulated and non-stimulated cells...

  16. Long-term motor cortex stimulation for phantom limb pain.

    Science.gov (United States)

    Pereira, Erlick A C; Moore, Tom; Moir, Liz; Aziz, Tipu Z

    2015-04-01

    We present the long-term course of motor cortex stimulation to relieve a case of severe burning phantom arm pain after brachial plexus injury and amputation. During 16-year follow-up the device continued to provide efficacious analgesia. However, several adjustments of stimulation parameters were required, as were multiple pulse generator changes, antibiotics for infection and one electrode revision due to lead migration. Steady increases in stimulation parameters over time were required. One of the longest follow-ups of motor cortex stimulation is described; the case illustrates challenges and pitfalls in neuromodulation for chronic pain, demonstrating strategies for maintaining analgesia and overcoming tolerance.

  17. Stimulation of two step degradation of sodium ascorbate by lignins.

    Science.gov (United States)

    Sakagami, H; Satoh, K

    1996-01-01

    Alkali-lignin stimulated the degradation of sodium ascorbate in phosphate-buffered saline, fetal bovine serum and culture medium, but not in distilled water. ESR spectroscopy revealed that alkali-lignin stimulated ascorbyl radical production even in distilled water. Similar stimulation activity was found in several other plant extracts, commercial and natural lignified materials. These data suggest that the lignin-stimulated degradation process of ascorbate might be separated into two processes, the first being the ascorbyl radical production process and the second the degradation process.

  18. Broadband stimulated Raman spectroscopy in the deep ultraviolet region

    Science.gov (United States)

    Kuramochi, Hikaru; Fujisawa, Tomotsumi; Takeuchi, Satoshi; Tahara, Tahei

    2017-09-01

    We report broadband stimulated Raman measurements in the deep ultraviolet (DUV) region, which enables selective probing of the aromatic amino acid residues inside proteins through the resonance enhancement. We combine the narrowband DUV Raman pump pulse (1000 cm-1) to realize stimulated Raman measurements covering a >1500 cm-1 spectral window. The stimulated Raman measurements for neat solvents, tryptophan, tyrosine, and glucose oxidase are performed using 240- and 290-nm Raman pump, highlighting the high potential of the DUV stimulated Raman probe for femtosecond time-resolved study of proteins.

  19. Double electrodes simultaneous stimulation and implantation technique in deep brain stimulation

    Institute of Scientific and Technical Information of China (English)

    BIAN Liu-guan; W Tirakotai; DK Schulte; H Bertalanffy; D Hellwig

    2005-01-01

    @@ Posttraumatic tremor is often one of the causes of disability in head injury patients. Usually, pharmacotherapy for this type of tremor is not effective. Since early 1970s, surgical ablation of the ventral thalamus has been used to treat various types of tremor.1 Nowadays, deep brain stimulation (DBS) confirms its efficacy in alleviating different forms of tremor, including posttraumatic tremor.2,3 Such therapy has been reported achieving around 80% success rate in the treatment of posttraumatic tremor.

  20. Expectation of sensory stimulation modulates brain activation during visual motion stimulation.

    Science.gov (United States)

    Brandt, Thomas; Deutschländer, Angela; Glasauer, Stefan; Nolte, Annina; Brückmann, Hartmut; Dieterich, Marianne; Stephan, Thomas

    2005-04-01

    The differential effects of visual hemifield motion stimulation during fixation of a stationary target were compared under two conditions: fixation straight ahead without any further instructions and fixation straight ahead with attention shifted to the "dark hemifield." Data from nine right-handed volunteers revealed that striate and extrastriate right hemispheric visual areas exhibited larger activations during left hemifield motion stimulation when attention was shifted to the right dark hemifield. Montreal Neurological Institute (MNI) coordinates (26, -98, -4) of the additional clusters activated in the latter condition corresponded best to the kinetic occipital region, which is known to process both shape and motion information, and to parts of area V3 posterior to V3A, which has been shown repeatedly to mediate motion perception. A simple computational model of transhemispheric visuovisual interaction is proposed. The basic mechanism of this model is a central predictor formed by a feedback loop that detects a mismatch between input to the two hemispheres. Predicted stimulation is then compared with the actual input. If the sensed motion of a visual hemifield is larger than the predicted net motion in the model, activation of the respective neural population is increased; conversely, a smaller actual motion causes less activation.

  1. Effect of transcutaneous electrical nerve stimulation induced parotid stimulation on salivary flow

    Directory of Open Access Journals (Sweden)

    Sreenivasulu Pattipati

    2013-01-01

    Full Text Available Aims and Objectives: The main objective of this study was to evaluate the duration of stimulation over the parotid salivary flow following the use of transcutaneous electric nerve stimulation (TENS in different age groups. Materials and Methods: The study was carried out in three different age groups. Under group A individuals from 21 to 35 years of age, group B 36-50 years and group C above 51 years were considered. In each group 30 subjects were taken of whom 15 were males and 15 were females. The placement of pads was approximated bilaterally over the parotid glands. The working parameters of TENS unit were fixed at 50 Hz and the unit was in normal mode. Results: Subjects belonging to group B were showing statistically significant increases in the duration of stimulated parotid salivary flow following the use of TENS. Conclusion: TENS can be considered as a non-pharmacological alternative to improve salivation for longer period in xerostomia patients.

  2. Moving Forward by Stimulating the Brain: Transcranial Direct Current Stimulation in Post-Stroke Hemiparesis.

    Science.gov (United States)

    Peters, Heather T; Edwards, Dylan J; Wortman-Jutt, Susan; Page, Stephen J

    2016-01-01

    Stroke remains a leading cause of disability worldwide, with a majority of survivors experiencing long term decrements in motor function that severely undermine quality of life. While many treatment approaches and adjunctive strategies exist to remediate motor impairment, many are only efficacious or feasible for survivors with active hand and wrist function, a population who constitute only a minority of stroke survivors. Transcranial direct current stimulation (tDCS), a type of non-invasive brain stimulation, has been increasingly utilized to increase motor function following stroke as it is able to be used with stroke survivors of varying impairment levels, is portable, is relatively inexpensive and has few side effects and contraindications. Accordingly, in recent years the number of studies investigating its efficacy when utilized as an adjunct to motor rehabilitation regimens has drastically increased. While many of these trials have reported positive and promising efficacy, methodologies vary greatly between studies, including differences in stimulation parameters, outcome measures and the nature of physical practice. As such, an urgent need remains, centering on the need to investigate these methodological differences and synthesize the most current evidence surrounding the application of tDCS for post-stroke motor rehabilitation. Accordingly, the purpose of this paper is to provide a detailed overview of the most recent tDCS literature (published 2014-2015), while highlighting these variations in methodological approach, as well to elucidate the mechanisms associated with tDCS and post-stroke motor re-learning and neuroplasticity.

  3. Reducing muscle fatigue due to functional electrical stimulation using random modulation of stimulation parameters.

    Science.gov (United States)

    Thrasher, Adam; Graham, Geoffrey M; Popovic, Milos R

    2005-06-01

    A major limitation of many functional electrical stimulation (FES) applications is that muscles tend to fatigue very rapidly. It was hypothesized that FES-induced muscle fatigue could be reduced by randomly modulating the pulse frequency, amplitude, and pulse width in a range of +/-15%. Seven subjects with spinal-cord injuries participated in this study. FES was applied to quadriceps and tibialis anterior muscles using surface electrodes. Isometric force was measured, and the time for the force to drop by 3 dB (fatigue time) was compared between trials. Four different modes of FES were applied in random order: constant stimulation, randomized frequency, randomized amplitude, and randomized pulse width. There was no significant difference between the fatigue-time measurements for the four modes of stimulation (P=0.329). Therefore, random modulation appeared to have no effect. Based on an observed correlation between maximum force measurements and trial order, we concluded that having 10-min rest periods between trials was insufficient.

  4. High permeability cores to optimize the stimulation of deeply located brain regions using transcranial magnetic stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Salvador, R; Miranda, P C [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences, University of Lisbon, 1749-016 Lisbon (Portugal); Roth, Y [Advanced Technology Center, Sheba Medical Center, Tel-Hashomer (Israel); Zangen, A [Neurobiology Department, Weizmann Institute of Science, Rehovot 76100 (Israel)], E-mail: rnsalvador@fc.ul.pt

    2009-05-21

    Efficient stimulation of deeply located brain regions with transcranial magnetic stimulation (TMS) poses many challenges, arising from the fact that the induced field decays rapidly and becomes less focal with depth. We propose a new method to improve the efficiency of TMS of deep brain regions that combines high permeability cores, to increase focality and field intensity, with a coil specifically designed to induce a field that decays slowly with increasing depth. The performance of the proposed design was investigated using the finite element method to determine the total electric field induced by this coil/core arrangement on a realistically shaped homogeneous head model. The calculations show that the inclusion of the cores increases the field's magnitude by as much as 25% while also decreasing the field's decay with depth along specific directions. The focality, as measured by the area where the field's norm is greater than 1/{radical}2 of its maximum value, is also improved by as much as 15% with some core arrangements. The coil's inductance is not significantly increased by the cores. These results show that the presence of the cores might make this specially designed coil even more suited for the effective stimulation of deep brain regions.

  5. Molecular characterization and expression of prothoracicotropic hormone during development and pupal diapause in the cotton bollworm, Helicoverpa armigera.

    Science.gov (United States)

    Wei, Zhao-Jun; Zhang, Qi-Rui; Kang, Le; Xu, Wei-Hua; Denlinger, David L

    2005-06-01

    Using a strategy of rapid amplification of cDNA ends, the cDNA encoding prothoracicotropic hormone (PTTH) was cloned from the brain of Helicoverpa armigera (Hearm). The Hearm-PTTH cDNA contains an open reading frame encoding a 226-amino acid preprohormone, which shows high identity with the closely related noctuid moths, Helicoverpa zea (98%) and Heliothis virescens (94%), and low identity with five species of Bombycoidea: Bombyx mori (57%), Manduca sexta (55%), Hyalophora cecropia (52%), Samia cynthia ricini (49%) and Antheraea peryni (48%). Hearm-PTTH cDNA shares important structural characterization known from other PTTHs, such as seven cysteine residues, proteolytic cleavage site, glycosylation site, and hydrophobic regions within the mature peptides. Northern blot analysis indicated a 0.9kb transcript present only in the brain. Using the more sensitive technique of RT-PCR, PTTH mRNA was also detected in the subesophageal ganglion, thoracic ganglion, abdominal ganglion, midgut and fat body. During the pupal stage, PTTH mRNA in the brain remained at a constant high level in nondiapausing individuals, was low in diapausing pupae, but increased again at diapause termination. The PTTH protein was detected only in the brain by Western blot analysis. Immunocytochemical results revealed that Hearm-PTTH is localized in two pairs of dorsolateral neurosecretory cells within the brain. Recombinant Hearm-PTTH was successfully expressed in E. coli, and purified recombinant-PTTH was effective in breaking pupal diapause. The results are consistent with a role for PTTH in the regulation of diapause in this species.

  6. Electrical stimulation vs. pulsed and continuous-wave optical stimulation of the rat prostate cavernous nerves, in vivo

    Science.gov (United States)

    Perkins, William C.; Lagoda, Gwen A.; Burnett, Arthur; Fried, Nathaniel M.

    2015-07-01

    Identification and preservation of the cavernous nerves (CNs) during prostate cancer surgery is critical for post-operative sexual function. Electrical nerve stimulation (ENS) mapping has previously been tested as an intraoperative tool for CN identification, but was found to be unreliable. ENS is limited by the need for electrode-tissue contact, poor spatial precision from electrical current spreading, and stimulation artifacts interfering with detection. Alternatively, optical nerve stimulation (ONS) provides noncontact stimulation, improved spatial selectivity, and elimination of stimulation artifacts. This study compares ENS to pulsed/CW ONS to explore the ONS mechanism. A total of eighty stimulations were performed in 5 rats, in vivo. ENS (4 V, 5 ms, 10 Hz) was compared to ONS using a pulsed diode laser nerve stimulator (1873 nm, 5 ms, 10 Hz) or CW diode laser nerve stimulator (1455 nm). Intracavernous pressure (ICP) response and nerve compound action potentials (nCAPs) were measured. All three stimulation modes (ENS, ONS-CW, ONS-P) produced comparable ICP magnitudes. However, ENS demonstrated more rapid ICP response times and well defined nCAPs compared to unmeasurable nCAPs for ONS. Further experiments measuring single action potentials during ENS and ONS are warranted to further understand differences in the ENS and ONS mechanisms.

  7. Facilitating access to emotions: neural signature of EMDR stimulation.

    Directory of Open Access Journals (Sweden)

    Deborah Herkt

    Full Text Available Eye Movement Desensitisation and Reprocessing (EMDR is a method in psychotherapy effective in treating symptoms of posttraumatic stress disorder. The client attends to alternating bilateral visual, auditory or sensory stimulation while confronted with emotionally disturbing material. It is thought that the bilateral stimulation as a specific element of EMDR facilitates accessing and processing of negative material while presumably creating new associative links. We hypothesized that the putatively facilitated access should be reflected in increased activation of the amygdala upon bilateral EMDR stimulation even in healthy subjects.We investigated 22 healthy female university students (mean 23.5 years with fMRI. Subjects were scanned while confronted with blocks of disgusting and neutral picture stimuli. One third of the blocks was presented without any additional stimulation, one third with bilateral simultaneous auditory stimulation, and one third with bilateral alternating auditory stimulation as used in EMDR.Contrasting disgusting vs. neutral picture stimuli confirmed the expected robust effect of amygdala activation for all auditory stimulation conditions. The interaction analysis with the type of auditory stimulation revealed a specific increase in activation of the right amygdala for the bilateral alternating auditory stimulation. Activation of the left dorsolateral prefrontal cortex showed the opposite effect with decreased activation.We demonstrate first time evidence for a putative neurobiological basis of the bilateral alternating stimulation as used in the EMDR method. The increase in limbic processing along with decreased frontal activation is in line with theoretical models of how bilateral alternating stimulation could help with therapeutic reintegration of information, and present findings may pave the way for future research on EMDR in the context of posttraumatic stress disorder.

  8. Tractography patterns of subthalamic nucleus deep brain stimulation.

    Science.gov (United States)

    Vanegas-Arroyave, Nora; Lauro, Peter M; Huang, Ling; Hallett, Mark; Horovitz, Silvina G; Zaghloul, Kareem A; Lungu, Codrin

    2016-04-01

    Deep brain stimulation therapy is an effective symptomatic treatment for Parkinson's disease, yet the precise mechanisms responsible for its therapeutic effects remain unclear. Although the targets of deep brain stimulation are grey matter structures, axonal modulation is known to play an important role in deep brain stimulation's therapeutic mechanism. Several white matter structures in proximity to the subthalamic nucleus have been implicated in the clinical benefits of deep brain stimulation for Parkinson's disease. We assessed the connectivity patterns that characterize clinically beneficial electrodes in Parkinson's disease patients, after deep brain stimulation of the subthalamic nucleus. We evaluated 22 patients with Parkinson's disease (11 females, age 57 ± 9.1 years, disease duration 13.3 ± 6.3 years) who received bilateral deep brain stimulation of the subthalamic nucleus at the National Institutes of Health. During an initial electrode screening session, one month after deep brain stimulation implantation, the clinical benefits of each contact were determined. The electrode was localized by coregistering preoperative magnetic resonance imaging and postoperative computer tomography images and the volume of tissue activated was estimated from stimulation voltage and impedance. Brain connectivity for the volume of tissue activated of deep brain stimulation contacts was assessed using probabilistic tractography with diffusion-tensor data. Areas most frequently connected to clinically effective contacts included the thalamus, substantia nigra, brainstem and superior frontal gyrus. A series of discriminant analyses demonstrated that the strength of connectivity to the superior frontal gyrus and the thalamus were positively associated with clinical effectiveness. The connectivity patterns observed in our study suggest that the modulation of white matter tracts directed to the superior frontal gyrus and the thalamus is associated with favourable clinical

  9. Focal Hemodynamic Responses in the Stimulated Hemisphere During High-Definition Transcranial Direct Current Stimulation.

    Science.gov (United States)

    Muthalib, Makii; Besson, Pierre; Rothwell, John; Perrey, Stéphane

    2017-07-17

    High-definition transcranial direct current stimulation (HD-tDCS) using a 4 × 1 electrode montage has been previously shown using modeling and physiological studies to constrain the electric field within the spatial extent of the electrodes. The aim of this proof-of-concept study was to determine if functional near-infrared spectroscopy (fNIRS) neuroimaging can be used to determine a hemodynamic correlate of this 4 × 1 HD-tDCS electric field on the brain. In a three session cross-over study design, 13 healthy males received one sham (2 mA, 30 sec) and two real (HD-tDCS-1 and HD-tDCS-2, 2 mA, 10 min) anodal HD-tDCS targeting the left M1 via a 4 × 1 electrode montage (anode on C3 and 4 return electrodes 3.5 cm from anode). The two real HD-tDCS sessions afforded a within-subject replication of the findings. fNIRS was used to measure changes in brain hemodynamics (oxygenated hemoglobin integral-O2 Hbint ) during each 10 min session from two regions of interest (ROIs) in the stimulated left hemisphere that corresponded to "within" (Lin ) and "outside" (Lout ) the spatial extent of the 4 × 1 electrode montage, and two corresponding ROIs (Rin and Rout ) in the right hemisphere. The ANOVA showed that both real anodal HD-tDCS compared to sham induced a significantly greater O2 Hbint in the Lin than Lout ROIs of the stimulated left hemisphere; while there were no significant differences between the real and sham sessions for the right hemisphere ROIs. Intra-class correlation coefficients showed "fair-to-good" reproducibility for the left stimulated hemisphere ROIs. The greater O2 Hbint "within" than "outside" the spatial extent of the 4 × 1 electrode montage represents a hemodynamic correlate of the electrical field distribution, and thus provides a prospective reliable method to determine the dose of stimulation that is necessary to optimize HD-tDCS parameters in various applications. © 2017 International Neuromodulation Society.

  10. Noradrenergic Stimulation Impairs Memory Generalization in Women.

    Science.gov (United States)

    Kluen, Lisa Marieke; Agorastos, Agorastos; Wiedemann, Klaus; Schwabe, Lars

    2017-03-02

    Memory generalization is essential for adaptive decision-making and action. Our ability to generalize across past experiences relies on medial-temporal lobe structures, known to be highly sensitive to stress. Recent evidence suggests that stressful events may indeed interfere with memory generalization. Yet, the mechanisms involved in this generalization impairment are unknown. We tested here whether a pharmacological elevation of major stress mediators, noradrenaline, and glucocorticoids is sufficient to disrupt memory generalization. In a double-blind, placebo-controlled design, healthy men and women received orally a placebo, hydrocortisone, the α2-adrenoceptor antagonist yohimbine that leads to increased noradrenergic stimulation, or both drugs, before they completed an associative learning task probing memory generalization. Drugs left learning performance intact. Yohimbine, however, led to a striking generalization impairment in women, but not in men. Hydrocortisone, in turn, had no effect on memory generalization, neither in men nor in women. The present findings indicate that increased noradrenergic activity, but not cortisol, is sufficient to disrupt memory generalization in a sex-specific manner, with relevant implications for stress-related mental disorders characterized by generalization deficits.

  11. New Incentives to Stimulate Data Publication

    Science.gov (United States)

    Urban, E. R.; Lowry, R.; Pissierssens, P.

    2008-12-01

    Data from ocean observations and experiments often are not submitted to appropriate data centers, or if they are submitted, may not be easily retrievable. These problems arise for a variety of reasons. Data are not always submitted, even when required by the agency funding the research, because the rewards for submitting data are not strong enough. Once data are submitted, the typical data center disaggregates the data into its component parameters, so it is difficult to get all the data related to a particular experiment back out of the system. With the advent of persistent identifiers, like digital object identifiers , the rapid evolution of the high-speed Internet, and the availability of large digital storage capacities that enable the transfer and storage of comprehensive data sets, it is now possible to restructure data management in a way that will create new incentives for ocean scientists to submit their data, for others to use it, and for the originating scientists to get credit for their effort and creativity in collecting the data. This presentation will report on a new activity of the Scientific Committee on Oceanic Research and the International Ocean Data and Information Exchange of UNESCO's Intergovernmental Oceanographic Commission that is mapping out new ways to (1) submit the data underlying the figures and tables in traditionally published papers to a recognized repository and link it to the publication, and (2) stimulate the submission of data publications that can be cited on originating scientists' CVs.

  12. Body weight gain and deep brain stimulation.

    Science.gov (United States)

    Rieu, Isabelle; Derost, Philippe; Ulla, Miguel; Marques, Ana; Debilly, Bérangère; De Chazeron, Ingrid; Chéreau, Isabelle; Lemaire, Jean Jacques; Boirie, Yves; Llorca, Pierre Michel; Durif, Franck

    2011-11-15

    Deep brain stimulation (DBS) is a neurosurgical technique that has now been available for some 25 years. It is used in the treatment of various motor disorders, e.g. Parkinson's disease (PD), essential tremor and dystonia, and neuropsychiatric illnesses, e.g. obsessive-compulsive disorder and Tourette syndrome. The surgical targets of DBS include the thalamic ventralis intermedius nucleus (Vim), the globus pallidus internus (GPi) and more recently the subthalamic nucleus (STN), currently considered as the reference target in the treatment of PD. In the last ten years, most studies in PD patients have described a rapid and marked weight gain in the months following DBS of the STN. This weight gain sometimes induces obesity and can have metabolic repercussions. The physiopathological mechanisms responsible for the weight gain are multifactorial (changes in energy metabolism and eating behaviour, reduction of motor complications, etc.). This review reports current knowledge concerning weight changes in patients treated by DBS with different surgical targets. It also describes the mechanisms responsible for weight gain and the health outcome for the patients.

  13. [Rehabilitation Using Repetitive Transcranial Magnetic Stimulation].

    Science.gov (United States)

    Takeuchi, Naoyuki; Izumi, Shin-Ichi

    2017-03-01

    Various novel stroke rehabilitative methods have been developed based on findings in basic science and clinical research. Recently, many reports have shown that repetitive transcranial magnetic stimulation (rTMS) improves function in stroke patients by altering the excitability of the human cortex. The interhemispheric competition model proposes that deficits in stroke patients are due to reduced output from the affected hemisphere and excessive interhemispheric inhibition from the unaffected hemisphere to the affected hemisphere. The interhemispheric competition model indicates that improvement in deficits can be achieved either by increasing the excitability of the affected hemisphere using excitatory rTMS or by decreasing the excitability of the unaffected hemisphere using inhibitory rTMS. Recovery after stroke is related to neural plasticity, which involves developing new neural connections, acquiring new functions, and compensating for impairments. Artificially modulating the neural network by rTMS may induce a more suitable environment for use-dependent plasticity and also may interfere with maladaptive neural activation, which weakens function and limits recovery. There is potential, therefore, for rTMS to be used as an adjuvant therapy for developed neurorehabilitation techniques in stroke patients.

  14. Bibliometric profile of deep brain stimulation.

    Science.gov (United States)

    Hu, Kejia; Moses, Ziev B; Xu, Wendong; Williams, Ziv

    2017-05-08

    We aimed to identify and analyze the characteristics of the 100 most highly-cited papers in the research field of deep brain stimulation (DBS). The Web of Science was searched for highly-cited papers related to DBS research. The number of citations, countries, institutions of origin, year of publication, and research area were noted and analyzed. The 100 most highly-cited articles had a mean of 304.15 citations. These accrued an average of 25.39 citations a year. The most represented target by far was the subthalamic nucleus (STN). These articles were published in 46 high-impact journals, with Brain (n = 10) topping the list. These articles came from 11 countries, with the USA contributing the most highly-cited articles (n = 29); however, it was the University of Toronto (n = 13) in Canada that was the institution with the most highly-cited studies. This study identified the 100 most highly-cited studies and highlighted a historical perspective on the progress in the field of DBS. These findings allow for the recognition of the most influential reports and provide useful information that can indicate areas requiring further investigation.

  15. [New stimulants of corneal reparative regeneration].

    Science.gov (United States)

    Egorov, E A; Kalinin, N I; Kiiasov, A P

    1999-01-01

    The efficacy of corneregel, a drug containing pantothenic acid, a component of coenzyme A, in healing of corneal wounds has been evaluated. The study was carried out on 19 rabbits (38 eyes) with standard corneal defect made with a 5-mm trephine for lamellar transplantation of the cornea, divided into 2 groups: 1) instillations of corneregel (10 eyes) and 0.25% levomycetin solution (10 eyes) and 2) 20% solcoseryl gel (9 eyes) and 0.25% levomycetin (9 eyes). Time course of changes were evaluated by biomicroscopy (fluorescent test), histologically (hematoxylin-eosin staining), and immunohistochemically after 1, 2, 4, 7, 30, and 90 days. Proliferative activity was studied by expression of the proliferating cell nuclear antigen and the migration capacity of cells by expression of alpha-smooth muscle actin. The terms of epithelialization were as follows: corneregel 10 +/- 7 h, 20% solcoseryl gel 108 +/- 10 h, levomycetin 124 +/- 6.93 h. Earlier epithelialization in the corneregel group was apparently due to increased expression of alpha-smooth muscle actin and increase in the cell migration capacity. Hence, corneregel is recommended for practical use as a stimulant of reparative regeneration of the cornea.

  16. Laser-stimulated fluorescence in paleontology.

    Science.gov (United States)

    Kaye, Thomas G; Falk, Amanda R; Pittman, Michael; Sereno, Paul C; Martin, Larry D; Burnham, David A; Gong, Enpu; Xu, Xing; Wang, Yinan

    2015-01-01

    Fluorescence using ultraviolet (UV) light has seen increased use as a tool in paleontology over the last decade. Laser-stimulated fluorescence (LSF) is a next generation technique that is emerging as a way to fluoresce paleontological specimens that remain dark under typical UV. A laser's ability to concentrate very high flux rates both at the macroscopic and microscopic levels results in specimens fluorescing in ways a standard UV bulb cannot induce. Presented here are five paleontological case histories that illustrate the technique across a broad range of specimens and scales. Novel uses such as back-lighting opaque specimens to reveal detail and detection of specimens completely obscured by matrix are highlighted in these examples. The recent cost reductions in medium-power short wavelength lasers and use of standard photographic filters has now made this technique widely accessible to researchers. This technology has the potential to automate multiple aspects of paleontology, including preparation and sorting of microfossils. This represents a highly cost-effective way to address paleontology's preparatory bottleneck.

  17. Stimulating nitrate removal processes of restored wetlands.

    Science.gov (United States)

    Ballantine, Kate A; Groffman, Peter M; Lehmann, Johannes; Schneider, Rebecca L

    2014-07-01

    The environmental and health effects caused by nitrate contamination of aquatic systems are a serious problem throughout the world. A strategy proposed to address nitrate pollution is the restoration of wetlands. However, although natural wetlands often remove nitrate via high rates of denitrification, wetlands restored for water quality functions often fall below expectations. This may be in part because key drivers for denitrification, in particular soil carbon, are slow to develop in restored wetlands. We added organic soil amendments that range along a gradient of carbon lability to four newly restored wetlands in western New York to investigate the effect of carbon additions on denitrification and other processes of the nitrogen cycle. Soil carbon increased by 12.67-63.30% with the use of soil amendments (p ≤ 0.0001). Soil nitrate, the carbon to nitrogen ratio, and microbial biomass nitrogen were the most significant predictors of denitrification potential. Denitrification potential, potential net nitrogen nitrification and mineralization, and soil nitrate and ammonium, were highest in topsoil-amended plots, with increases in denitrification potential of 161.27% over control plots. While amendment with topsoil more than doubled several key nitrogen cycling processes, more research is required to determine what type and level of amendment application are most effective for stimulating removal of exogenous nitrate and meeting functional goals within an acceptable time frame.

  18. Trans-dentinal stimulation of tertiary dentinogenesis.

    Science.gov (United States)

    Smith, A J; Murray, P E; Sloan, A J; Matthews, J B; Zhao, S

    2001-08-01

    Trans-dentinal stimulation of tertiary dentinogenesis has long been recognized, and has traditionally been ascribed to diffusion of irritant substances arising during injury and restorative treatment. Identification of bio-active components, especially growth factors including TGF-beta s, sequestered within dentin matrix provides a new explanation for cellular signaling during tertiary dentinogenesis. Both isolated dentin matrix components and pure growth factors (TGF-beta s) have been shown to signal cellular events leading to reactionary and reparative tertiary dentinogenesis. Release of these bio-active components from dentin matrix may arise during carious attack and other injury to the tissue, and also during subsequent surgical intervention and restoration of the tooth. Both cavity-conditioning agents and leaching from restorative materials may contribute to release of these components. Distance of diffusion, as determined by cavity residual dentin thickness, and other restorative parameters may influence the signaling process after release of these components. Careful consideration of the interplay between tissue injury and surgical and restorative material factors is required for optimum exploitation of the exquisite regenerative capacity of dentin-pulp for more biological approaches to clinical treatment of dental disease.

  19. Does simvastatin stimulate bone formation in vivo?

    Directory of Open Access Journals (Sweden)

    Chorev Michael

    2003-04-01

    Full Text Available Abstract Background Statins, potent compounds that inhibit cholesterol synthesis in the liver have been reported to induce bone formation, both in tissue culture and in rats and mice. To re-examine potential anabolic effects of statins on bone formation, we compared the activity of simvastatin (SVS to the known anabolic effects of PTH in an established model of ovariectomized (OVX Swiss-Webster mice. Methods Mice were ovariectomized at 12 weeks of age (T0, remained untreated for 5 weeks to allow development of osteopenia (T5, followed by treatment for 8 weeks (T13. Whole, trabecular and cortical femoral bone was analyzed by micro-computed tomography (micro CT. Liquid chromatography/mass spectrometry (LC/MS was used to detect the presence of SVS and its active metabolite, simvastatin β-hydroxy acid (SVS-OH in the mouse serum. Results Trabecular BV/TV at T13 was 4.2 fold higher in animals treated with PTH (80 micro-g/kg/day compared to the OVX-vehicle treated group (p in vivo study. Conclusions While PTH demonstrated the expected anabolic effect on bone, SVS failed to stimulate bone formation, despite our verification by LC/MS of the active SVS-OH metabolite in mouse serum. While statins have clear effects on bone formation in vitro, the formulation of existing 'liver-targeted' statins requires further refinement for efficacy in vivo.

  20. Increased biogas production using microbial stimulants.

    Science.gov (United States)

    Singh, S; Kumar, S; Jain, M C; Kumar, D

    2001-07-01

    Laboratory studies were undertaken to evaluate the effect of microbial stimulants Aquasan and Teresan, on biogas yields from cattle dung and combined residues of cattle dung and kitchen waste, respectively. The addition of single dose of Aquasan at the rate of 10, 15 and 20 ppm to cattle dung on the first day of incubation resulted in increased gas yields ranging between 45.1 and 62.1 l/kg dry matter. Subsequent addition of Aquasan at 15 and 20 ppm dosage after a period of 15 days increased the gas yields by 15-16%. The gas production was found to be optimum at a dosage level of 15 ppm and was 39% and 55% higher with single and dual additions, respectively, than untreated cattle dung. In another bench scale study (1:1 dry matter) the addition of Teresan at 10 ppm concentration to the mixed residues of cattle dung and kitchen wastes at different solids concentration, produced 34.8% more gas (272.4 l/kg d.m.) than the uninoculated mixture at 15% TS concentration (202.4 l/kg d.m.).

  1. Mechanical Stimulation by Postnasal Drip Evokes Cough.

    Directory of Open Access Journals (Sweden)

    Toshiyuki Iwata

    Full Text Available Cough affects all individuals at different times, and its economic burden is substantial. Despite these widespread adverse effects, cough research relies on animal models, which hampers our understanding of the fundamental cause of cough. Postnasal drip is speculated to be one of the most frequent causes of chronic cough; however, this is a matter of debate. Here we show that mechanical stimuli by postnasal drip cause chronic cough. We distinguished human cough from sneezes and expiration reflexes by airflow patterns. Cough and sneeze exhibited one-peak and two-peak patterns, respectively, in expiratory airflow, which were also confirmed by animal models of cough and sneeze. Transgenic mice with ciliary dyskinesia coughed substantially and showed postnasal drip in the pharynx; furthermore, their cough was completely inhibited by nasal airway blockade of postnasal drip. We successfully reproduced cough observed in these mice by injecting artificial postnasal drip in wild-type mice. These results demonstrated that mechanical stimulation by postnasal drip evoked cough. The findings of our study can therefore be used to develop new antitussive drugs that prevent the root cause of cough.

  2. Mechanical Stimulation by Postnasal Drip Evokes Cough.

    Science.gov (United States)

    Iwata, Toshiyuki; Ito, Isao; Niimi, Akio; Ikegami, Koji; Marumo, Satoshi; Tanabe, Naoya; Nakaji, Hitoshi; Kanemitsu, Yoshihiro; Matsumoto, Hisako; Kamei, Junzo; Setou, Mitsutoshi; Mishima, Michiaki

    2015-01-01

    Cough affects all individuals at different times, and its economic burden is substantial. Despite these widespread adverse effects, cough research relies on animal models, which hampers our understanding of the fundamental cause of cough. Postnasal drip is speculated to be one of the most frequent causes of chronic cough; however, this is a matter of debate. Here we show that mechanical stimuli by postnasal drip cause chronic cough. We distinguished human cough from sneezes and expiration reflexes by airflow patterns. Cough and sneeze exhibited one-peak and two-peak patterns, respectively, in expiratory airflow, which were also confirmed by animal models of cough and sneeze. Transgenic mice with ciliary dyskinesia coughed substantially and showed postnasal drip in the pharynx; furthermore, their cough was completely inhibited by nasal airway blockade of postnasal drip. We successfully reproduced cough observed in these mice by injecting artificial postnasal drip in wild-type mice. These results demonstrated that mechanical stimulation by postnasal drip evoked cough. The findings of our study can therefore be used to develop new antitussive drugs that prevent the root cause of cough.

  3. Ethical issues in deep brain stimulation

    Directory of Open Access Journals (Sweden)

    Maartje eSchermer

    2011-05-01

    Full Text Available Deep brain stimulation (DBS is currently used to treat neurological disorders like Parkinson’s disease (PD, essential tremor and dystonia, and is explored as an experimental treatment for psychiatric disorders like Major Depression (MD and Obsessive Compulsive Disorder (OCD. This mini review discusses ethical issues in DBS treatment and research, as they have been discussed in the medical and ethical literature.With regard to DBS treatment, the most important issues are balancing risks and benefits and ensuring respect for the autonomous wish of the patient. This implies special attention to patient selection, psycho-social impact of treatment, effects on personal identity, and treatment of children. Moreover, it implies a careful informed consent process in which unrealistic expectations of patients and their families are addressed and in which special attention is given to competence. In the context of research, the fundamental ethical challenge is to promote high-quality scientific research in the interest of future patients, while at the same time safeguarding the rights and interests of vulnerable research subjects. Several guidelines have been proposed to ensure this. One of the preconditions to further development of responsible and transparent research practices is the establishment of a comprehensive registry.

  4. Deep Brain Stimulation, Authenticity and Value.

    Science.gov (United States)

    Nyholm, Sven; O'Neill, Elizabeth

    2017-10-01

    In this article, we engage in dialogue with Jonathan Pugh, Hannah Maslen, and Julian Savulescu about how to best interpret the potential impacts of deep brain stimulation on the self. We consider whether ordinary peoples' convictions about the true self should be interpreted in essentialist or existentialist ways. Like Pugh, Maslen, and Savulescu, we argue that it is useful to understand the notion of the true self as having both essentialist and existentialist components. We also consider two ideas from existentialist philosophy-Jean-Paul Sartre and Simone de Beauvoir's ideas about "bad faith" and "ambiguity"-to argue that there can be value to patients in regarding themselves as having a certain amount of freedom to choose what aspects of themselves should be considered representative of their true selves. Lastly, we consider the case of an anorexia nervosa patient who shifts between conflicting mind-sets. We argue that mind-sets in which it is easier for the patient and his or her family to share values can plausibly be considered to be more representative of the patient's true self, if this promotes a well-functioning relationship between the patient and the family. However, we also argue that families are well advised to give patients room to determine what such shared values mean to them, as it can be alienating for patients if they feel that others try to impose values on them from the outside.

  5. Electrical stimulation counteracts muscle decline in seniors.

    Science.gov (United States)

    Kern, Helmut; Barberi, Laura; Löfler, Stefan; Sbardella, Simona; Burggraf, Samantha; Fruhmann, Hannah; Carraro, Ugo; Mosole, Simone; Sarabon, Nejc; Vogelauer, Michael; Mayr, Winfried; Krenn, Matthias; Cvecka, Jan; Romanello, Vanina; Pietrangelo, Laura; Protasi, Feliciano; Sandri, Marco; Zampieri, Sandra; Musaro, Antonio

    2014-01-01

    The loss in muscle mass coupled with a decrease in specific force and shift in fiber composition are hallmarks of aging. Training and regular exercise attenuate the signs of sarcopenia. However, pathologic conditions limit the ability to perform physical exercise. We addressed whether electrical stimulation (ES) is an alternative intervention to improve muscle recovery and defined the molecular mechanism associated with improvement in muscle structure and function. We analyzed, at functional, structural, and molecular level, the effects of ES training on healthy seniors with normal life style, without routine sport activity. ES was able to improve muscle torque and functional performances of seniors and increased the size of fast muscle fibers. At molecular level, ES induced up-regulation of IGF-1 and modulation of MuRF-1, a muscle-specific atrophy-related gene. ES also induced up-regulation of relevant markers of differentiating satellite cells and of extracellular matrix remodeling, which might guarantee shape and mechanical forces of trained skeletal muscle as well as maintenance of satellite cell function, reducing fibrosis. Our data provide evidence that ES is a safe method to counteract muscle decline associated with aging.

  6. Vaccines against stimulants: cocaine and MA.

    Science.gov (United States)

    Kosten, Thomas; Domingo, Coreen; Orson, Frank; Kinsey, Berma

    2014-02-01

    While the worldwide prevalence of cocaine use remains significant, medications, or small molecule approaches, to treat drug addictions have met with limited success. Anti-addiction vaccines, on the other hand, have demonstrated great potential for treating drug abuse using a distinctly different mechanism of eliciting an antibody response that blocks the pharmacological effects of drugs. We provide a review of vaccine-based approaches to treating stimulant addictions; specifically and cocaine addictions. This selective review article focuses on the one cocaine vaccine that has been into clinical trials and presents new data related to pre-clinical development of a methamphetamine (MA) vaccine. We also review the mechanism of action for vaccine induced antibodies to abused drugs, which involves kinetic slowing of brain entry as well as simple blocking properties. We present pre-clinical innovations for MA vaccines including hapten design, linkage to carrier proteins and new adjuvants beyond alum. We provide some new information on hapten structures and linkers and variations in protein carriers. We consider a carrier, outer membrance polysaccharide coat protein (OMPC), that provides some self-adjuvant through lipopolysaccharide components and provide new results with a monophosopholipid adjuvant for the more standard carrier proteins with cocaine and MA. The review then covers the clinical trials with the cocaine vaccine TA-CD. The clinical prospects for advances in this field over the next few years include a multi-site cocaine vaccine clinical trial to be reported in 2013 and phase 1 clinical trials of a MA vaccine in 2014.

  7. Laser-stimulated fluorescence in paleontology.

    Directory of Open Access Journals (Sweden)

    Thomas G Kaye

    Full Text Available Fluorescence using ultraviolet (UV light has seen increased use as a tool in paleontology over the last decade. Laser-stimulated fluorescence (LSF is a next generation technique that is emerging as a way to fluoresce paleontological specimens that remain dark under typical UV. A laser's ability to concentrate very high flux rates both at the macroscopic and microscopic levels results in specimens fluorescing in ways a standard UV bulb cannot induce. Presented here are five paleontological case histories that illustrate the technique across a broad range of specimens and scales. Novel uses such as back-lighting opaque specimens to reveal detail and detection of specimens completely obscured by matrix are highlighted in these examples. The recent cost reductions in medium-power short wavelength lasers and use of standard photographic filters has now made this technique widely accessible to researchers. This technology has the potential to automate multiple aspects of paleontology, including preparation and sorting of microfossils. This represents a highly cost-effective way to address paleontology's preparatory bottleneck.

  8. Nonacid Reactive Solution for deep well stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Pendergrass, J.; Bell, D.; Bishop, D.; Campbell, P.; Copeland, J.

    1984-04-01

    Certain formations in the Anardarko Basin have not responded well to acid-base cleanup or breakdown treatments. The use of a Nonacid Reactive Solution (NARS) for deep wells where both formation sensitivity and excessive corrosion of tubular goods present problems can produce improved well response. Laboratory analyses of the Morrow, Red Fork and Springer formations in the Anadarko Basin justify the use of NARS for stimulation treatments in these formations. Laboratory data and production results demonstrate that NARS can be used as an economical and effective method of mud removal in wells which are drilled with oil-base mud. Further studies investigate the effect of NARS on downhole tubular goods. Well histories in the three formations support the effectiveness of the fluid, and the variety of treatment designs dictated by the diverse formation characteristics demonstrates the versatility of NARS. By concentrating the study of rock lithologies, core and laboratory analyses, and production results, NARS can be used in breakdown and cleanup treatments more effectively than acid-base fluids in sensitive formations.

  9. Heavy Metals Stimulate Human LINE-1 Retrotransposition

    Directory of Open Access Journals (Sweden)

    Astrid M. Roy-Engel

    2005-04-01

    Full Text Available L1 and Alu elements are among the most active retroposons (mobile elements in the human genome. Several human diseases, including certain forms of breast cancer and leukemia, are associated with L1 and Alu insertions in functionally important areas of the genome. We present data demonstrating that environmental pollutants, such as heavy metals, can stimulate L1 retrotransposition in a tissue culture system using two different types of assays. The response to these agents was equivalent when using a cell line with a stably integrated L1 vector (genomic or a by introducing the L1 vector by transient transfection (episomal of the cell. Reproducible results showed that mercury (HgS, cadmium (CdS, and nickel (NiO increase the activity of L1 by an average of three (3 fold p<0.001. This observation is the first to link several carcinogenic agents with the increased retrotransposition activity of L1 as an alternate mechanism of generating genomic instability contributing to the process of carcinogenesis. Our results demonstrate that mobile element activation must be considered as one of the mechanisms when evaluating genomic damage/instability in response to environmental agents.

  10. Deep-brain stimulation for anorexia nervosa.

    Science.gov (United States)

    Wu, Hemmings; Van Dyck-Lippens, Pieter Jan; Santegoeds, Remco; van Kuyck, Kris; Gabriëls, Loes; Lin, Guozhen; Pan, Guihua; Li, Yongchao; Li, Dianyou; Zhan, Shikun; Sun, Bomin; Nuttin, Bart

    2013-01-01

    Anorexia nervosa (AN) is a complex and severe, sometimes life-threatening, psychiatric disorder with high relapse rates under standard treatment. After decades of brain-lesioning procedures offered as a last resort, deep-brain stimulation (DBS) has come under investigation in the last few years as a treatment option for severe and refractory AN. In this jointly written article, Sun et al. (the Shanghai group) report an average of 65% increase in body weight in four severe and refractory patients with AN after they underwent the DBS procedure (average follow-up: 38 months). All patients weighed greater than 85% of expected body weight and thus no longer met the diagnostic criteria of AN at last follow-up. Nuttin et al. (the Leuven group) describe other clinical studies that provide evidence for the use of DBS for AN and further discuss patient selection criteria, target selection, and adverse event of this evolving therapy. Preliminary results from the Shanghai group and other clinical centers showed that the use of DBS to treat AN may be a valuable option for weight restoration in otherwise-refractory and life-threatening cases. The nature of this procedure, however, remains investigational and should not be viewed as a standard clinical treatment option. Further scientific investigation is essential to warrant the long-term efficacy and safety of DBS for AN. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. Intracellular Biopotentials During Static Extracellular Stimulation

    Science.gov (United States)

    Klee, Maurice

    1973-01-01

    Two properties of the intracellular potentials and electric fields resulting from static extracellular stimulation are obtained for arbitrarily shaped cells. First, the values of intracellular potential are shown to be bounded by the maximum and minimum values of extracellular potential on the surface of the cell. Second, the volume average of the magnitude of intracellular electric field is shown to have an upper bound given by the ratio of the magnitude of the largest extracellular potential difference on the surface of the cell to a generalized length constant λ = [σintraVcell/(σmemb Acell)]1/2, where Vcell and Acell are the volume and surface area of the cell, σintra is the intracellular conductivity (reciprocal ohms per centimeter), and σmemb is the membrane conductivity (reciprocal ohms per square centimeter). The use of the upper bound on the volume average of the magnitude of intracellular electric field as an estimate for intracellular isopotentiality is discussed and the use of the generalized length constant for electrically describing arbitrary cells is illustrated for cylindrical- and spheroidal-shaped cells. PMID:4726882

  12. CREATIVITY AND ENTREPRENEURSHIP. METHODS OF STIMULATING CREATIVITY

    Directory of Open Access Journals (Sweden)

    Maria Irina Dromereschi

    2017-01-01

    Full Text Available Creativity as producing new information system, you can put in what seems unconnected connection, after so many forms of the unfold plan and in content. An entrepreneur will think and do new things or old things in a new form trying to transform ideas into tangible things, products and services. Entrepreneurship is the process through which all functions, activities and actions are shared to identify business opportunities and creating organizations through which they will be used in order to obtain profit and meeting social interests. Boosting creativity is justified in that creative activity is educated, even if some native elements have their own importance in the creative process. If we start from the idea that most barriers to creative thinking are all human creations, tributaries of the left hemisphere, will have to find alternative responses to stimulation, shaping and maintaining the creative process and even create organizational culture conducive to the creative process. Ideas are our tenement dwellers and often are near us in the simplest and quickest form. Just educate us the activation process and instituting the ideas process which involves methods fall under three broad categories: imaginative, heuristics and logical approach. Subject to the risk taken, the combination of these methods can provide as many alternatives to a reality whose details they ultimately determines who assumes the risk of their own decisions.

  13. Transcranial Magnetic Stimulation Studies in Alzheimer's Disease

    Directory of Open Access Journals (Sweden)

    Andrea Guerra

    2011-01-01

    Full Text Available Although motor deficits affect patients with Alzheimer's disease (AD only at later stages, recent studies demonstrated that primary motor cortex is precociously affected by neuronal degeneration. It is conceivable that neuronal loss is compensated by reorganization of the neural circuitries, thereby maintaining motor performances in daily living. Effectively several transcranial magnetic stimulation (TMS studies have demonstrated that cortical excitability is enhanced in AD and primary motor cortex presents functional reorganization. Although the best hypothesis for the pathogenesis of AD remains the degeneration of cholinergic neurons in specific regions of the basal forebrain, the application of specific TMS protocols pointed out a role of other neurotransmitters. The present paper provides a perspective of the TMS techniques used to study neurophysiological aspects of AD showing also that, based on different patterns of cortical excitability, TMS may be useful in discriminating between physiological and pathological brain aging at least at the group level. Moreover repetitive TMS might become useful in the rehabilitation of AD patients. Finally integrated approaches utilizing TMS together with others neuro-physiological techniques, such as high-density EEG, and structural and functional imaging as well as biological markers are proposed as promising tool for large-scale, low-cost, and noninvasive evaluation of at-risk populations.

  14. Statistical properties of ionospheric stimulated electromagnetic emissions

    Directory of Open Access Journals (Sweden)

    R. L. Karlsson

    2006-08-01

    Full Text Available We have analysed the statistical properties of the stimulated electromagnetic emissions (SEE spectral features in the steady state, reached after a long period of continuous HF pumping of the ionosphere in experiments performed at the Sura ionospheric radio research facility in Russia. Using a digital filter bank method, we have been able to analyse complex valued signals within narrow frequency bands. Each of the SEE spectral features are thereby separated into a number of narrow spectral components. Statistical tests were performed for all these spectral components and the distributions of the spectral amplitudes and phases were evaluated. Also, a test for sinusoidal components was performed. These tests showed that all observed SEE features were indistinguishable from coloured Gaussian noise. The test results exclude that the SEE features can be the result of a single isolated coherent process, but does not rule out that there could be many statistically independent parametric wave-wave processes taking place simultaneously at various parts of the HF-pumped ionosphere, as long as the superposition from all these is incoherent. Furthermore, from the test results, we cannot exclude the possibility that the waveforms of some, or all, of the SEE features may be chaotic.

  15. Harmine stimulates proliferation of human neural progenitors

    Science.gov (United States)

    Dakic, Vanja; Maciel, Renata de Moraes; Drummond, Hannah; Nascimento, Juliana M.; Trindade, Pablo

    2016-01-01

    Harmine is the β-carboline alkaloid with the highest concentration in the psychotropic plant decoction Ayahuasca. In rodents, classical antidepressants reverse the symptoms of depression by stimulating neuronal proliferation. It has been shown that Ayahuasca presents antidepressant effects in patients with depressive disorder. In the present study, we investigated the effects of harmine in cell cultures containing human neural progenitor cells (hNPCs, 97% nestin-positive) derived from pluripotent stem cells. After 4 days of treatment, the pool of proliferating hNPCs increased by 71.5%. Harmine has been reported as a potent inhibitor of the dual specificity tyrosine-phosphorylation-regulated kinase (DYRK1A), which regulates cell proliferation and brain development. We tested the effect of analogs of harmine, an inhibitor of DYRK1A (INDY), and an irreversible selective inhibitor of monoamine oxidase (MAO) but not DYRK1A (pargyline). INDY but not pargyline induced proliferation of hNPCs similarly to harmine, suggesting that inhibition of DYRK1A is a possible mechanism to explain harmine effects upon the proliferation of hNPCs. Our findings show that harmine enhances proliferation of hNPCs and suggest that inhibition of DYRK1A may explain its effects upon proliferation in vitro and antidepressant effects in vivo. PMID:27957390

  16. Harmine stimulates proliferation of human neural progenitors

    Directory of Open Access Journals (Sweden)

    Vanja Dakic

    2016-12-01

    Full Text Available Harmine is the β-carboline alkaloid with the highest concentration in the psychotropic plant decoction Ayahuasca. In rodents, classical antidepressants reverse the symptoms of depression by stimulating neuronal proliferation. It has been shown that Ayahuasca presents antidepressant effects in patients with depressive disorder. In the present study, we investigated the effects of harmine in cell cultures containing human neural progenitor cells (hNPCs, 97% nestin-positive derived from pluripotent stem cells. After 4 days of treatment, the pool of proliferating hNPCs increased by 71.5%. Harmine has been reported as a potent inhibitor of the dual specificity tyrosine-phosphorylation-regulated kinase (DYRK1A, which regulates cell proliferation and brain development. We tested the effect of analogs of harmine, an inhibitor of DYRK1A (INDY, and an irreversible selective inhibitor of monoamine oxidase (MAO but not DYRK1A (pargyline. INDY but not pargyline induced proliferation of hNPCs similarly to harmine, suggesting that inhibition of DYRK1A is a possible mechanism to explain harmine effects upon the proliferation of hNPCs. Our findings show that harmine enhances proliferation of hNPCs and suggest that inhibition of DYRK1A may explain its effects upon proliferation in vitro and antidepressant effects in vivo.

  17. Plasmon-enhanced optically stimulated luminescence

    Energy Technology Data Exchange (ETDEWEB)

    Guidelli, E. J.; Baffa, O. [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Fisica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Ramos, A. P., E-mail: ederguidelli@gmail.com [Universidade de Sao Paulo, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Departamento de Quimica, Av. Bandeirantes 3900, 14040-901 Ribeirao Preto, Sao Paulo (Brazil)

    2015-10-15

    Full text: Optically Stimulated Luminescence dosimeters (OSLD) have been largely used for personal, medical, and industrial radiation dosimetry. Developing highly sensitive and small-sized radiation detectors and dosimeters is essential for improving spatial resolution and consequently diagnosis quality and treatment efficacy in the case of applications in radiodiagnosis and radiation therapy, for instance. Conventional methods to improve the OSLD sensitivity consist of doping and co-doping the host materials with atoms of other elements, thereby increasing the amount of trapping and/or luminescent centers. Our group is researching on the use of the plasmon properties of noble metal nanoparticles to increase OSL intensity. Upon incidence of a light beam with appropriate resonant wavelengths, the oscillation of the free electrons at the nanoparticle surface originates the Localized Surface Plasmons (LSP) and the consequent plasmon resonance band. The interaction between the LSP and the surrounding luminescent material leads to new optical properties largely employed for enhancing several luminescent processes. Here we will show our results regarding the use of LSP to increase OSLD sensitivity. The interaction between the traps/luminescent centers and the plasmons depends on the distance between them, on the plasmon resonance band intensity and position, as well as on the surrounding medium. Therefore, the plasmon-enhanced luminescence is a promising tool to develop more sensitive and miniaturized OSLD. (Author)

  18. Pressure changes under the ischial tuberosities during gluteal neuromuscular stimulation in spinal cord injury: a comparison of sacral nerve root stimulation with surface functional electrical stimulation.

    Science.gov (United States)

    Liu, Liang Qin; Ferguson-Pell, Martin

    2015-04-01

    To compare the magnitude of interface pressure changes during gluteal maximus contraction by stimulating sacral nerve roots with surface electrical stimulations in patients with spinal cord injuries (SCIs). Pilot interventional study. Spinal injury research laboratory. Adults (N=18) with suprasacral complete SCI. Sacral nerve root stimulation (SNRS) via a functional magnetic stimulator (FMS) or a sacral anterior root stimulator (SARS) implant; and surface functional electrical stimulation (FES). Interface pressure under the ischial tuberosity (IT) defined as peak pressure, gradient at peak pressure, and average pressure. With optimal FMS, a 29% average reduction of IT peak pressure was achieved during FMS (mean ± SD: 160.1±24.3mmHg at rest vs 114.7±18.0mmHg during FMS, t5=6.3, P=.002). A 30% average reduction of peak pressure during stimulation via an SARS implant (143.2±31.7mmHg at rest vs 98.5±21.5mmHg during SARS, t5=4.4, P=.007) and a 22% average decrease of IT peak pressure during FES stimulation (153.7±34.8mmHg at rest vs 120.5±26.1mmHg during FES, t5=5.3, P=.003) were obtained. In 4 participants who completed both the FMS and FES studies, the percentage of peak pressure reduction with FMS was slightly greater than with FES (mean difference, 7.8%; 95% confidence interval, 1.6%-14.0; P=.04). SNRS or surface FES can induce sufficient gluteus maximus contraction and significantly reduce ischial pressure. SNRS via an SARS implant may be more convenient and efficient for frequently activating the gluteus maximus. Copyright © 2015 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  19. Handedness, repetitive transcranial magnetic stimulation and bulimic disorders.

    Science.gov (United States)

    Van den Eynde, F; Broadbent, H; Guillaume, S; Claudino, A; Campbell, I C; Schmidt, U

    2012-05-01

    Repetitive Transcranial Magnetic Stimulation (rTMS) research in psychiatry mostly excludes left-handed participants. We recruited left-handed people with a bulimic disorder and found that stimulation of the left prefrontal cortex may result in different effects in left- and right-handed people. This highlights the importance of handedness and cortex lateralisation for rTMS.

  20. Infrared laser stimulation of retinal and vestibular neurons

    Science.gov (United States)

    Bardin, Fabrice; Bec, Jean-Michel; Albert, Emmanuelle S.; Hamel, Christian; Dupeyron, Gérard; Chabbert, Christian; Marc, Isabelle; Dumas, Michel

    2011-03-01

    The study of laser-neuron interaction has gained interest over the last few years not only for understanding of fundamental mechanisms but also for medical applications such as prosthesis because of the non-invasive characteristic of the laser stimulation. Several authors have shown that near infrared lasers are able to stimulate neurons. It is suggested that a thermal gradient induced by the absorption of the laser radiation on cells is the primary effect but the exact mechanism remains unclear. We show in this work that infrared laser radiations provide a possible way for stimulating retinal and vestibular ganglion cells. We describe relevant physical characteristics allowing safe and reproducible neuron stimulations by single infrared pulses. Calcium fluorescence imaging and electrophysiological recordings have been used to measure ionic exchanges at the neuron membrane. The stimulation system is based on a pulsed laser diode beam of a few mW. Effects of three different wavelengths (from 1470 to 1875 nm) and stimulation durations have been investigated. Variations of the stimulation energy thresholds suggest that the main physical parameter is the water optical absorption. Measurements of the temperature at the cell membrane show that a constant temperature rise is required to stimulate neurons, suggesting a photothermal process.