Articoli di riviste: "Spectron"

1

Chekhova, M. V. "Two-photon spectron". Journal of Experimental and Theoretical Physics Letters 75, n. 5 (marzo 2002): 225–26. http://dx.doi.org/10.1134/1.1478518.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

2

Meigh-Andrews, Chris. "Peter Donebauer, Richard Monkhouse and the Development of the EMS Spectron and the Videokalos Image Processor". Leonardo 40, n. 5 (ottobre 2007): 463–67. http://dx.doi.org/10.1162/leon.2007.40.5.463.

Testo completo

Abstract (sommario):

The author details the development of two early color video synthesizers, the EMS Spectron and the Videokalos Image Processor, and examines their influence on video-based art. The Spectron, developed by Richard Monkhouse for Electronic Music Studios, influenced both its creator and various artists in the development of video-based art and images. Artist Peter Donebauer collaborated with Monkhouse to produce the Videokalos, leading to several artworks and a series of live performances.

Gli stili APA, Harvard, Vancouver, ISO e altri

3

Gómez, Daniel. "Spectron: Graphical Model for Interacting With Timbre". TecnoLógicas, n. 22 (27 giugno 2009): 61. http://dx.doi.org/10.22430/22565337.232.

Testo completo

Abstract (sommario):

Los algoritmos para crear y manipular el sonido por medios electrónicos o digitales han crecido en cantidad y complejidad desde la creación de los primeros sintetizadores análogos. Sin embargo, las técnicas para visualizar estos modelos de síntesis no han crecido a la par de los sintetizadores hardware o software. En este artículo se muestran posibilidades para representar y controlar gráficamente el timbre, basadas en la visualización de los parámetros involucrados en su modelo de síntesis. Un grupo de datos muy simple fue extraído de un sintetizador substractivo comercial y analizado con dos aproximaciones diferentes, reducción dimensional y visualización abstracta de datos. Los resultados de estas aproximaciones diferentes fueron usados como lineamientos para crear un prototipo de sintetizador digital: el sintetizador Spectron. Este prototipo usa el gráfico de Amplitud vs. Frecuencia como su principal herramienta para informar a cerca del timbre e interactuar con el, fue desarrollado en PureData y su control plantea una simplificación en la cantidad de variables de un oscilador clásico al mismo tiempo que expande las posibilidades para generar timbres adicionales a los de estos osciladores clásicos.

Gli stili APA, Harvard, Vancouver, ISO e altri

4

Carlson, Lawrence E., Bob Radocy e Peter D. Marschall. "Spectron 12 Cable for Upper-Limb Prostheses". JPO Journal of Prosthetics and Orthotics 3, n. 3 (ottobre 1991): 130???141. http://dx.doi.org/10.1097/00008526-199106000-00010.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

5

Garellick, Göran, Henrik Malchau e Peter Herberts. "The charnley versus the spectron hip prosthesis". Journal of Arthroplasty 14, n. 4 (giugno 1999): 407–13. http://dx.doi.org/10.1016/s0883-5403(99)90095-5.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

6

Garellick, Göran, Henrik Malchau, Hans Regnér e Peter Herberts. "The charnley versus the spectron hip prosthesis". Journal of Arthroplasty 14, n. 4 (giugno 1999): 414–25. http://dx.doi.org/10.1016/s0883-5403(99)90096-7.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

7

Karapetyan, N., H. Toneyan, A. Kutuzyan, M. Sukiasyan, V. Avetisyan, D. Gulqanyan, K. Apresyan e L. Mouradian. "Numerical Study of Spectron Shaping Process: Phase Peculiarities". Journal of Contemporary Physics (Armenian Academy of Sciences) 53, n. 2 (aprile 2018): 129–35. http://dx.doi.org/10.3103/s1068337218020044.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

8

Teeter, Matthew G., Richard W. McCalden, Xunhua Yuan, Steven J. MacDonald e Douglas D. Naudie. "Predictive accuracy of RSA migration thresholds for cemented total hip arthroplasty stem designs". HIP International 28, n. 4 (20 maggio 2018): 363–68. http://dx.doi.org/10.1177/1120700018762179.

Testo completo

Abstract (sommario):

Introduction: Radiostereometric analysis (RSA) migration thresholds for cemented total hip stems have been established beyond which an unacceptably high risk of revision is likely to occur. These thresholds are subsidence >0.23 mm or >1.2 mm after 2 years. The purpose of this study was to retrospectively examine after long-term follow-up the predictive accuracy of the two thresholds. Methods: Data from two previous prospective RSA trials with 2 year follow-up for which minimum 10 year survivorship data was available were used. Thirty-six patients received a Spectron stem, 17 patients received an Exeter stem, and 17 patients received a CPCS stem. Subsidence after 2 years was compared to the migration thresholds, and long-term survivorship and clinical outcome scores were obtained. Results: At 2 years, the Spectron stem subsided 0.046 ± 0.160 mm, the Exeter stem subsided 1.218 ± 0.320 mm, and the CPCS stem subsided 0.681 ± 0.246 mm ( p < 0.0001). The Spectron stem passed both thresholds, the Exeter stem failed both thresholds, and the CPCS stem passed 1 and failed 1 threshold. At 10 years, survivorship exceeded 90% for all stems. Conclusion: All stems demonstrated strong 10 year survivorship and equivalent clinical outcome scores, but this success would not have been equally predicted across RSA migration thresholds. Although RSA is a useful predictive tool, care should be taken in applying migration thresholds only to those stem designs they are indicated for, with the threshold of 1.2 mm of subsidence at 2 years being most broadly applicable.

Gli stili APA, Harvard, Vancouver, ISO e altri

9

de Izarra, G., C. Jammes, B. Geslot, J. Di Salvo e C. Destouches. "SPECTRON, a neutron noise measurement system in frequency domain". Review of Scientific Instruments 86, n. 11 (novembre 2015): 115111. http://dx.doi.org/10.1063/1.4935250.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

10

Edwards High Vacuum International. "Modem link trouble shoots remote Spectron 3000 leak detectors". Vacuum 40, n. 3 (1990): 319–20. http://dx.doi.org/10.1016/0042-207x(90)90054-3.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

11

Kristensen, T. B., E. Dybvik, O. Furnes, L. B. Engesæter e J.-E. Gjertsen. "More reoperations for periprosthetic fracture after cemented hemiarthroplasty with polished taper-slip stems than after anatomical and straight stems in the treatment of hip fractures". Bone & Joint Journal 100-B, n. 12 (dicembre 2018): 1565–71. http://dx.doi.org/10.1302/0301-620x.100b12.bjj-2018-0262.r1.

Testo completo

Abstract (sommario):

Aims The aim of this large registry-based study was to compare mid-term survival rates of cemented femoral stems of different designs used in hemiarthroplasty for a fracture of the femoral neck. Patients and Methods From the Norwegian Hip Fracture Register (NHFR), 20 532 primary cemented bipolar hemiarthroplasties, which were undertaken in patients aged > 70 years with a femoral neck fracture between 2005 and 2016, were included. Polished tapered stems (n = 12 065) (Exeter and CPT), straight stems (n = 5545) (Charnley, Charnley Modular, and Spectron EF), and anatomical stems (n = 2922) (Lubinus SP2) were included. The survival of the implant with any reoperation as the endpoint was calculated using the Kaplan–Meier method and hazard ratios (HRs), and the different indications for reoperation were calculated using Cox regression analysis. Results The one-year survival was 96.0% (95% confidence interval (CI) 95.6 to 96.4) for the Exeter stem, 97.0% (95% CI 96.4 to 97.6) for the Lubinus SP2 stem, 97.6% (95% CI 97.0 to 98.2) for the Charnley stem, 98.1% (95% CI 97.3 to 98.9) for the Spectron EF stem, and 96.4% (95% CI 95.6 to 97.2) for the Charnley Modular stem, respectively. The hazard ratio for reoperation after one year was lower for Lubinus SP2 (HR 0.77, 95% CI 0.60 to 0.97), Charnley (HR 0.64, 95% CI 0.48 to 0.86), and Spectron EF stems (HR 0.44, 95% CI 0.29 to 0.67) compared with the Exeter stem. Reoperation for periprosthetic fracture occurred almost exclusively after the use of polished tapered stems. Conclusion We were able to confirm that implant survival after cemented hemiarthroplasty for a hip fracture is high. Differences in rates of reoperation seem to favour anatomical and straight stems compared with polished tapered stems, which had a higher risk of periprosthetic fracture.

Gli stili APA, Harvard, Vancouver, ISO e altri

12

Negrín, Miguel A., Julian Nam e Andrew H. Briggs. "Bayesian Solutions for Handling Uncertainty in Survival Extrapolation". Medical Decision Making 37, n. 4 (8 giugno 2016): 367–76. http://dx.doi.org/10.1177/0272989x16650669.

Testo completo

Abstract (sommario):

Objective. Survival extrapolation using a single, best-fit model ignores 2 sources of model uncertainty: uncertainty in the true underlying distribution and uncertainty about the stability of the model parameters over time. Bayesian model averaging (BMA) has been used to account for the former, but it can also account for the latter. We investigated BMA using a published comparison of the Charnley and Spectron hip prostheses using the original 8-year follow-up registry data. Methods. A wide variety of alternative distributions were fitted. Two additional distributions were used to address uncertainty about parameter stability: optimistic and skeptical. The optimistic (skeptical) model represented the model distribution with the highest (lowest) estimated probabilities of survival but reestimated using, as prior information, the most optimistic (skeptical) parameter estimated for intermediate follow-up periods. Distributions were then averaged assuming the same posterior probabilities for the optimistic, skeptical, and noninformative models. Cost-effectiveness was compared using both the original 8-year and extended 16-year follow-up data. Results. We found that all models obtained similar revision-free years during the observed period. In contrast, there was variability over the decision time horizon. Over the observed period, we detected considerable uncertainty in the shape parameter for Spectron. After BMA, Spectron was cost-effective at a threshold of £20,000 with 93% probability, whereas the best-fit model was 100%; by contrast, with a 16-year follow-up, it was 0%. Conclusions. This case study casts doubt on the ability of the single best-fit model selected by information criteria statistics to adequately capture model uncertainty. Under this scenario, BMA weighted by posterior probabilities better addressed model uncertainty. However, there is still value in regularly updating health economic models, even where decision uncertainty is low.

Gli stili APA, Harvard, Vancouver, ISO e altri

13

Briggs, AH, MJ Sculpher, J. Dawson e H. Malchau. "POD14: COST-EFFECTIVENESS ANALYSIS OF THE SPECTRON VERSUS CHARNLEY HIP PROSTHESES". Value in Health 4, n. 6 (settembre 2001): 471. http://dx.doi.org/10.1016/s1098-3015(11)71661-8.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

14

Issack, Paul S., Herman G. Botero, Rudi N. Hiebert, Matthew R. Bong, Steven A. Stuchin, Joseph D. Zuckerman e Paul E. Di Cesare. "Sixteen-year follow-up of the cemented spectron femoral stem for hip arthroplasty". Journal of Arthroplasty 18, n. 7 (ottobre 2003): 925–30. http://dx.doi.org/10.1016/s0883-5403(03)00336-x.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

15

Rebelo-Mochel, Flávia, e Flávio J. Ponzoni. "Spectral characterization of mangrove leaves in the Brazilian Amazonian Coast: Turiaçu Bay, Maranhão State". Anais da Academia Brasileira de Ciências 79, n. 4 (dicembre 2007): 683–92. http://dx.doi.org/10.1590/s0001-37652007000400009.

Testo completo

Abstract (sommario):

Mangrove communities are tropical systems which have fewer species than tropical forests, especially in Latin America and display a single architecture, usually lacking the various strata commonly found in other forest ecosystems. The identification of mangrove communities by orbital data is not a difficult task but the most interesting challenge is to identify themselves by the dominant species. The first step toward that floristic identification is the spectral characterization of detached leaves. Leaves from four species of mangrove trees were spectrally characterized considering the Directional Hemispherical Reflectance Factor (DHRF) determined through radiometric measurements using an integrating sphere LICOR 1800 attached to a spectroradiometer SPECTRON SE-590. In the visible bands (0.45-0.69 µm) the button-shaped mangrove Conocarpus erectus was brighter and the red mangrove Rhizophora mangle was darker than the other two species which shows very close DHRF values. Otherwise the black mangrove Avicennia germinans and the white mangrove Laguncularia racemosa can be distinguished from one another in the Near Infra Red (NIR) region (0.76-0.90 µm and in this region of the spectrum the DHRF of C. erectus and R. mangle become very close.

Gli stili APA, Harvard, Vancouver, ISO e altri

16

Valle, Alejandro González Della, Adam Rana, Bryan Nestor, Mathias Bostrom, Geoffrey Westrich e Eduardo A. Salvati. "Metallic Shedding, Surface Finish Changes, and Extensive Femoral Osteolysis in the Loose Spectron EF Stem". Clinical Orthopaedics and Related Research 442 (gennaio 2006): 165–70. http://dx.doi.org/10.1097/01.blo.0000181145.01306.f9.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

17

Burston, Ben J., Jane H. Wood, James R. Lewis, Gareth H. Prosser, Laura Firth, David J. Wood e Piers J. Yates. "High Failure Rates of the Spectron EF Stem at a Minimum of 10Year's Follow-up". Journal of Arthroplasty 29, n. 10 (ottobre 2014): 1956–60. http://dx.doi.org/10.1016/j.arth.2014.05.003.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

18

Macdonald, W., L. V. Carlsson, C. M. Jacobsson e T. Q. Lee. "A proximal femoral implant preserves physiological bone deformation: A biomechanical investigation in cadaveric bones". Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 217, n. 1 (1 gennaio 2003): 41–48. http://dx.doi.org/10.1243/095441103762597638.

Testo completo

Abstract (sommario):

The aim of this study was to compare the perturbances in bone deformation patterns of the proximal femur due to a conventional cemented femoral stem and a novel uncemented implant designed on the principles of osseointegration. Five matched pairs of fresh frozen human femora were mechanically tested. Bone deformation patterns, measured with a video digitizing system under 1.5 kN joint force, showed that the cemented Spectron femoral implant caused significant alterations to the proximal femoral deformation pattern, whereas the Gothenburg osseointegrated titanium femoral implant did not significantly alter the bone behaviour (p < 0.05). Vertical micromotions measured under 1 kN after 1000 cycles were within the threshold of movement tolerable for bone ingrowth (21 μm for the Gothenburg system and 26 μm for the cemented implant).

Gli stili APA, Harvard, Vancouver, ISO e altri

19

Moreira, Mauricio Alves, Bernardo Friedrich Theodor Rudorff, João Carlos Felício, José Guilherme de Freitas e Marcelo dos Santos Targa. "Variação espectral e eficiência de uso da radiação fotossinteticamente ativa em ensaio com genótipos de trigo". Bragantia 64, n. 3 (2005): 331–38. http://dx.doi.org/10.1590/s0006-87052005000300003.

Testo completo

Abstract (sommario):

Medidas de radiometria de campo são utilizadas para quantificar a variação espectral e a eficiência de uso da radiação solar na produção de fitomassa (épsilonF), em um experimento com 20 genótipos de trigo, cultivado na área experimental da Universidade de Taubaté, Taubaté, SP, durante o período de maio a outubro de 1999. A cultura foi irrigada em intervalos semanais, visando manter o solo próximo à capacidade de campo. Foram obtidas oito medidas do fator de refletância da cultura do trigo, entre a emergência das plântulas e a maturação fisiológica dos grãos com o radiômetro Spectron SE-590. Essas medidas foram transformadas no índice de vegetação com diferença normalizada (IVDN) e, juntamente com dados de radiação fotossinteticamente ativa (RFA), foram utilizadas no cálculo da RFA absorvida acumulada (RFAAA) ao longo do ciclo da cultura, a fim de estimar os valores de épsilonF. Pelo resultado, em eF observou-se significativa variação entre genótipos, a técnica de radiometria de campo é uma ferramenta promissora na identificação de genótipos com maior épsilonF, e ainda, para produção de fitomassa, o aproveitamento da radiação, no processo fotossintético, é bem mais relevante do que a RFAAA.

Gli stili APA, Harvard, Vancouver, ISO e altri

20

Tavares Júnior, João Batista, Daniel Rodrigues Dos Santos, Flavio Jorge Ponzoni, Quintino Dalmolin e Alzir Felippe Buffara Antunes. "DETECÇÃO DA PROPAGAÇÃO URBANA DA ERVA-DEPASSARINHO (LORANTHACEAE SP) UTILIZANDO TÉCNICAS DE SENSORIAMENTO REMOTO". Revista Brasileira de Cartografia 63, n. 4 (31 dicembre 2011): 545–53. http://dx.doi.org/10.14393/rbcv63n4-49226.

Testo completo

Abstract (sommario):

A detecção da ocorrência da erva-de-passarinho em árvores no meio urbano é relevante devido a vários fatores e atranstornos que ela pode causar. Dentre eles, destaca-se o sufocamento e a conseqüente morte da espécie arbóreahospedeira, descaracterizando o padrão de arborização urbana, além de possíveis acidentes provocados pela suaqueda. Atualmente, a detecção é realizada através de observações in-loco com anotações em planilhas ou mapas paraposteriores providências. O objetivo deste trabalho foi de avaliar se há diferenças espectrais significativas entre aresposta espectral das folhas da erva-de-passarinho em relação às folhas do seu hospedeiro, de tal forma que sejapossível a realização da detecção a partir de técnicas de sensoriamento remoto. Um espectrômetro SPECTRON SE-590(350 - 1100nm) acoplado a uma esfera integradora, foi utilizado para gerar os fatores de reflectância de 150 folhas dequatro espécies de erva-de-passarinho e de três espécies arbóreas hospedeiras. Testes estatísticos mostraram que acombinação dos fatores de reflectância nas faixas do azul, do verde, do vermelho e do infravermelho próximo geram diferenças significativas e que permitem que técnicas de Sensoriamento Remoto sejam utilizadas para detectar a ocorrênciae o monitoramento da propagação da erva-de-passarinho, tornando o trabalho de detecção nos indivíduosarbóreos mais eficiente em termos de custos e de prazos.

Gli stili APA, Harvard, Vancouver, ISO e altri

21

Kadar, Thomas, Geir Hallan, Arild Aamodt, Kari Indrekvam, Mona Badawy, Leif Ivar Havelin, Terje Stokke, Kristin Haugan, Birgitte Espehaug e Ove Furnes. "A randomized study on migration of the Spectron EF and the Charnley flanged 40 cemented femoral components using radiostereometric analysis at 2 years". Acta Orthopaedica 82, n. 5 (ottobre 2011): 538–44. http://dx.doi.org/10.3109/17453674.2011.618914.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

22

Sahabieva, Dzhamilya, Mikhail Deev, Elena D'yanonenko, Irina Poyurovskaya, Fedor Rusanov e Igor' Lebedenko. "EFFECT OF HIGH-SPEED SINTERING OF RUSSIAN PRODUCED ZICERAM T ZIRCONIA-BASED CERAMIC MATERIAL ON STRENGTH AND COLOR". Actual problems in dentistry 17, n. 4 (4 febbraio 2022): 140–44. http://dx.doi.org/10.18481/2077-7566-21-17-4-140-144.

Testo completo

Abstract (sommario):

Zirconia dentures are gradually becoming a widespread type of dental prosthetics. The production of zirconia blanks for dentistry has been launched in our country. In recent years, the possibility of high-speed sintering of zirconia dentures has been well studied, which makes it possible to reduce the manufacturing process of dental restorations by four to five times. Zirconia ceramics compositions and high-speed sintering furnaces are being improved, sintering protocols are being optimized. In this paper, we reported about the influence of high-speed firing protocols on important material`s characteristic, such as three-point bend flexural strength and color parameters at ten different heating modes, differing by heating rates, final temperature and holding time during high-speed heat treatment of ceramic material. Accord-ing to the results of bending strength tests, samples obtained with a total time of high-speed firing from 20 to 60 minutes have similar values, more than 300 MPa. In accordance with the ISO 6872 standard, such flexural strength is sufficient for fabrication of single crowns in both the anterior and posterior groups of teeth. A study on the laboratory spectrophotometer (Spectron M) in the CIELab system, showed a multidirectional change in color characteristics at different heating rates and sintering temperatures. An increase in the value of zirconia sam-ples from domestic blanks "Ziceram T" produced by St. Petersburg firm "Zircon Ceramics" was established with a sufficient confidence grade. The shortened firing time leads to an in-crease in the value of the samples, which associate with a lower translucency.

Gli stili APA, Harvard, Vancouver, ISO e altri

23

Sakhabieva, Djamilia A., Mikhail S. Deev, Elena E. Dyakonenko, Irina Ya Poyurovskaya, Fedor S. Rusanov e Igor Yu Lebedenko. "Effect of high-speed sintering modes of Russian zirconia samples made of Ziceram T on strength indicators and color". Russian Journal of Dentistry 26, n. 2 (4 settembre 2022): 95–102. http://dx.doi.org/10.17816/1728-2802-2022-26-2-95-102.

Testo completo

Abstract (sommario):

BACKGROUND: In recent years, zirconia prostheses have gradually become a mass type of orthopedic treatment. The production of zirconium dioxide blanks for dentistry has also been launched in our country. In recent years, the possibility of speed sintering of dental prostheses made of zirconia has been widely calculated, which makes it possible to reduce the process of manufacturing structures by four to five times. AIM: To investigate the effect of high-speed sintering on important properties, such as strength characteristics during three-point bending and color parameters at 10 different modes of speed sintering of ceramic materials. MATERIALS AND METHODS: The work uses samples obtained by computer-aided design and computer-aided manufacturing milling from domestic Ziceram T blanks, color A2. Depending on the firing modes, the samples were divided into 11 groups. The strength of the sintered samples was studied with three-point bending on a bursting machine. The color parameters of the samples were determined on the Spectron-M color analyzer in the CIE L*a*b system on a white and black background using acceptable norms of color difference and characteristics of color shades. RESULTS: According to the results of tests for resistance to bending, susceptibility has an approximate value of more than 300 MPa. According to ISO 6872, this flexural strength is sufficient for the fabrication чof single crowns in both anterior and posterior teeth. An increase in the lightness of ceramic samples based on zirconium dioxide from domestic factories Ziceram T of Zircon Ceramics was established. The reduced firing time led to an increase in body weight, which is associated with a decrease in their intensity. CONCLUSION: Express firing modes of ceramics based on zirconium dioxide Ziceram T guarantee the achievement of the required strength. However, none of the studied firing modes allowed achieving the color parameters of the control samples.

Gli stili APA, Harvard, Vancouver, ISO e altri

24

Machnicka, Beata, Renata Grochowalska, Dżamila M. Bogusławska e Aleksander F. Sikorski. "The role of spectrin in cell adhesion and cell–cell contact". Experimental Biology and Medicine 244, n. 15 (21 giugno 2019): 1303–12. http://dx.doi.org/10.1177/1535370219859003.

Testo completo

Abstract (sommario):

Spectrins are proteins that are responsible for many aspects of cell function and adaptation to changing environments. Primarily the spectrin-based membrane skeleton maintains cell membrane integrity and its mechanical properties, together with the cytoskeletal network a support cell shape. The occurrence of a variety of spectrin isoforms in diverse cellular environments indicates that it is a multifunctional protein involved in numerous physiological pathways. Participation of spectrin in cell–cell and cell–extracellular matrix adhesion and formation of dynamic plasma membrane protrusions and associated signaling events is a subject of interest for researchers in the fields of cell biology and molecular medicine. In this mini-review, we focus on data concerning the role of spectrins in cell surface activities such as adhesion, cell–cell contact, and invadosome formation. We discuss data on different adhesion proteins that directly or indirectly interact with spectrin repeats. New findings support the involvement of spectrin in cell adhesion and spreading, formation of lamellipodia, and also the participation in morphogenetic processes, such as eye development, oogenesis, and angiogenesis. Here, we review the role of spectrin in cell adhesion and cell–cell contact.Impact statementThis article reviews properties of spectrins as a group of proteins involved in cell surface activities such as, adhesion and cell–cell contact, and their contribution to morphogenesis. We show a new area of research and discuss the involvement of spectrin in regulation of cell–cell contact leading to immunological synapse formation and in shaping synapse architecture during myoblast fusion. Data indicate involvement of spectrins in adhesion and cell–cell or cell–extracellular matrix interactions and therefore in signaling pathways. There is evidence of spectrin’s contribution to the processes of morphogenesis which are connected to its interactions with adhesion molecules, membrane proteins (and perhaps lipids), and actin. Our aim was to highlight the essential role of spectrin in cell–cell contact and cell adhesion.

Gli stili APA, Harvard, Vancouver, ISO e altri

25

Moorthy, Suraj, Lihsia Chen e Vann Bennett. "Caenorhabditis elegans β-G Spectrin Is Dispensable for Establishment of Epithelial Polarity, but Essential for Muscular and Neuronal Function". Journal of Cell Biology 149, n. 4 (15 maggio 2000): 915–30. http://dx.doi.org/10.1083/jcb.149.4.915.

Testo completo

Abstract (sommario):

The Caenorhabditis elegans genome encodes one α spectrin subunit, a β spectrin subunit (β-G), and a β-H spectrin subunit. Our experiments show that the phenotype resulting from the loss of the C. elegans α spectrin is reproduced by tandem depletion of both β-G and β-H spectrins. We propose that α spectrin combines with the β-G and β-H subunits to form α/β-G and α/β-H heteromers that perform the entire repertoire of spectrin function in the nematode. The expression patterns of nematode β-G spectrin and vertebrate β spectrins exhibit three striking parallels including: (1) β spectrins are associated with the sites of cell–cell contact in epithelial tissues; (2) the highest levels of β-G spectrin occur in the nervous system; and (3) β spec-trin-G in striated muscle is associated with points of attachment of the myofilament apparatus to adjacent cells. Nematode β-G spectrin associates with plasma membranes at sites of cell–cell contact, beginning at the two-cell stage, and with a dramatic increase in intensity after gastrulation when most cell proliferation has been completed. Strikingly, depletion of nematode β-G spectrin by RNA-mediated interference to undetectable levels does not affect the establishment of structural and functional polarity in epidermis and intestine. Contrary to recent speculation, β-G spectrin is not associated with internal membranes and depletion of β-G spectrin was not associated with any detectable defects in secretion. Instead β-G spectrin-deficient nematodes arrest as early larvae with progressive defects in the musculature and nervous system. Therefore, C. elegans β-G spectrin is required for normal muscle and neuron function, but is dispensable for embryonic elongation and establishment of early epithelial polarity. We hypothesize that heteromeric spectrin evolved in metazoans in response to the needs of cells in the context of mechanically integrated tissues that can withstand the rigors imposed by an active organism.

Gli stili APA, Harvard, Vancouver, ISO e altri

26

Howe, C. L., L. M. Sacramone, M. S. Mooseker e J. S. Morrow. "Mechanisms of cytoskeletal regulation: modulation of membrane affinity in avian brush border and erythrocyte spectrins." Journal of Cell Biology 101, n. 4 (1 ottobre 1985): 1379–85. http://dx.doi.org/10.1083/jcb.101.4.1379.

Testo completo

Abstract (sommario):

The spectrins isolated from chicken erythrocytes and chicken intestinal brush border, TW260/240, share a common alpha subunit and a tissue-specific beta subunit. The ability of these related proteins to bind human erythrocyte inside out vesicles (IOVs) and human erythrocyte ankyrin in vitro have been quantitatively compared with human erythrocyte spectrin. Chicken erythrocyte spectrin binds human IOVs and human ankyrin with affinities nearly identical to that for human erythrocyte spectrin. TW260/240 does not significantly bind to either IOVs or ankyrin. These results demonstrate a remarkable tissue preservation of ankyrin-binding capacity, even between diverse species, and confirm the role of the avian beta-spectrins in modulating this functionality. Avian brush border spectrin may represent a unique spectrin which serves primarily as a filament cross-linker and which does not interact strongly with membrane-associated proteins.

Gli stili APA, Harvard, Vancouver, ISO e altri

27

WEI Daoquan, 蔚道权, 王慧琴 WANG Huiqin, 王可 WANG Ke, 王展 WANG Zhan e 甄刚 ZHEN Gang. "基于空谱联合特征的壁画稀疏多光谱图像颜料分类方法". ACTA PHOTONICA SINICA 51, n. 4 (2022): 0430002. http://dx.doi.org/10.3788/gzxb20225104.0430002.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

28

Leto, T. L., D. Fortugno-Erikson, D. Barton, T. L. Yang-Feng, U. Francke, A. S. Harris, J. S. Morrow, V. T. Marchesi e E. J. Benz. "Comparison of nonerythroid alpha-spectrin genes reveals strict homology among diverse species". Molecular and Cellular Biology 8, n. 1 (gennaio 1988): 1–9. http://dx.doi.org/10.1128/mcb.8.1.1-9.1988.

Testo completo

Abstract (sommario):

The spectrins are a family of widely distributed filamentous proteins. In association with actin, spectrins form a supporting and organizing scaffold for cell membranes. Using antibodies specific for human brain alpha-spectrin (alpha-fodrin), we have cloned a rat brain alpha-spectrin cDNA from an expression library. Several closely related human clones were also isolated by hybridization. Comparison of sequences of these and other overlapping nonerythroid and erythroid alpha-spectrin genes demonstrated that the nonerythroid genes are strictly conserved across species, while the mammalian erythroid genes have diverged rapidly. Peptide sequences deduced from these cDNAs revealed that the nonerythroid alpha-spectrin chain, like the erythroid spectrin, is composed of multiple 106-amino-acid repeating units, with the characteristic invariant tryptophan as well as other charged and hydrophobic residues in conserved locations. However, the carboxy-terminal sequence varies markedly from this internal repeat pattern and may represent a specialized functional site. The nonerythroid alpha-spectrin gene was mapped to human chromosome 9, in contrast to the erythroid alpha-spectrin gene, which has previously been assigned to a locus on chromosome 1.

Gli stili APA, Harvard, Vancouver, ISO e altri

29

Leto, T. L., D. Fortugno-Erikson, D. Barton, T. L. Yang-Feng, U. Francke, A. S. Harris, J. S. Morrow, V. T. Marchesi e E. J. Benz. "Comparison of nonerythroid alpha-spectrin genes reveals strict homology among diverse species." Molecular and Cellular Biology 8, n. 1 (gennaio 1988): 1–9. http://dx.doi.org/10.1128/mcb.8.1.1.

Testo completo

Abstract (sommario):

The spectrins are a family of widely distributed filamentous proteins. In association with actin, spectrins form a supporting and organizing scaffold for cell membranes. Using antibodies specific for human brain alpha-spectrin (alpha-fodrin), we have cloned a rat brain alpha-spectrin cDNA from an expression library. Several closely related human clones were also isolated by hybridization. Comparison of sequences of these and other overlapping nonerythroid and erythroid alpha-spectrin genes demonstrated that the nonerythroid genes are strictly conserved across species, while the mammalian erythroid genes have diverged rapidly. Peptide sequences deduced from these cDNAs revealed that the nonerythroid alpha-spectrin chain, like the erythroid spectrin, is composed of multiple 106-amino-acid repeating units, with the characteristic invariant tryptophan as well as other charged and hydrophobic residues in conserved locations. However, the carboxy-terminal sequence varies markedly from this internal repeat pattern and may represent a specialized functional site. The nonerythroid alpha-spectrin gene was mapped to human chromosome 9, in contrast to the erythroid alpha-spectrin gene, which has previously been assigned to a locus on chromosome 1.

Gli stili APA, Harvard, Vancouver, ISO e altri

30

Данілова, І. С. "Вплив термічної обробки на вміст неорганічних елементів у м'ясі равликів". Вісник Полтавської державної аграрної академії, n. 1 (29 marzo 2019): 200–206. http://dx.doi.org/10.31210/visnyk2019.01.23.

Testo completo

Abstract (sommario):

Мета статті. Дослідити вміст неорганічних елементів у вареному м'ясі харчових видів равликів Helix pomatia, Helix aspersa maxima та Helix aspersa muller та проаналізувати одержані результати. Методика досліджень. Вміст неорганічних елементів визначали за допомогою рентгенофлуоресцентного аналізу на приладі «Спектроскан–МАКС - G» НВО «Спектрон». Для цього було сформовано 3 середні проби вареного м'яса равликів по 20,0 ±0,5г кожного виду. М'ясо було термічно оброблене впродовж 90 хвилин, бо саме за такий час м'ясо вважається готовим до вживання. Результати дослідження. Під впливом високої температури збільшилася кількість брому, цинку, стронцію, феруму і мангану та зменьшилася кількість купруму, кобальту, тоді як плюмбуму взагалі не виявлено порівняно із сирим м'ясом. Дані щодо вмісту неорганічних елементів були оприлюднені в раніше опублікованій роботі. Елементи наукової новизни. Вперше в Україні вивчено наявність і кількість неорганічних елементів у вареному м'ясі равликів Helix pomatiа, Helix aspersa maxima, Helix aspersa muller, які є харчовими видами і використовуються як делікатес. Практична значущість. Поряд з амінокислотним та вітамінним складом нами вивчено питання складу неорганічних елементів у вареному м'ясі равликів. Одержані нові дані ввійдуть до методичних рекомендацій. The purpose of the article was to investigate the content of inorganic elements in cooked meat of food species Helix pomatia, Helix aspersa maxima and Helix aspersa muller snails and to analyze the obtained results. Methods of the research. The content of inorganic elements was determined using X-ray fluorescence analysis in three replicates on the Spectroscan-MAX-G device of the Spectron RPA. The first reflection was the main parameter of the instrument for measuring spectral indicators. The value of the device step and the exposure time was 4. For this, 3 medium samples of boiled snail meat 20.0 ± 0.5 g of each species were taken. The meat was subjected to heat treatment for 90 minutes, because during this time the meat is considered to be ready for consumption. The research results. For the first time, not only in Ukraine, but also in the world, the influence of heat treatment on the amount of inorganic elements in the meat of Helix pomatia, Helix aspersa maxima, Helix aspersa muller, which are edible species and used as a delicacy, was studied. Snail meat is a source of 11 inorganic elements: strontium, bromine, selenium, zinc, cuprum, nickel, cobalt, ferrum, manganese, chromium, and calcium. Under the influence of high temperature, the amount of bromine, zinc, strontium, ferrum and manganese increased, and the amount of cuprum, cobalt decreased, while plumbum was not detected at all as compared with raw meat. Elements of scientific novelty. For the first time not only in Ukraine, but also in the world, we have studied the presence and number of inorganic elements in boiled meat of snails Helix pomatia, Helix aspersa maxima, Helix aspersa muller, which are food types and are used as a delicacy. Practical significance. Along with amino acid and vitamin compositions, we studied the question of inorganic elements’ composition in boiled snail meat. The obtained new data will be included in the methodical recommendations.

Gli stili APA, Harvard, Vancouver, ISO e altri

31

Lawler, J., TL Coetzer, VN Mankad, RB Moore, JT Prchal e J. Palek. "Spectrin-alpha I/61: a new structural variant of alpha-spectrin in a double-heterozygous form of hereditary pyropoikilocytosis". Blood 72, n. 4 (1 ottobre 1988): 1412–15. http://dx.doi.org/10.1182/blood.v72.4.1412.1412.

Testo completo

Abstract (sommario):

Abstract Recent biochemical studies have led to the identification of abnormal spectrins in the erythrocytes of patients with hereditary pyropoikilocytosis (HPP) and hereditary elliptocytosis (HE). In this report we describe the biochemical characterization of the erythrocytes from a proband with severe HPP who is doubly heterozygous for two mutant spectrins (Sp): Sp alpha I/74 and a new, previously undetected, mutant of alpha-spectrin designated Sp alpha I/61. The proband's erythrocytes are unstable when exposed to 45 degrees C, and her membrane skeletons exhibit instability to shear stress. The content of spectrin in the proband's erythrocyte membranes is decreased to 75% of control values. The amount of spectrin dimers in crude 4 degrees C spectrin extracts is increased (58%) as compared with control values (6% +/- 4%). Limited tryptic digestion reveals a marked decrease in the normal 80,000-dalton alpha I domain, an increase in the 74,000-dalton fragment that is characteristic of Sp alpha I/74, and an increase in a series of new fragments of 61,000, 55,000, 21,000, and 16,000 daltons. Both parents are asymptomatic, but they have increased amounts of spectrin dimers (17% to 25%). Limited tryptic digestion of the father's spectrin demonstrates the presence of a previously identified abnormal spectrin (Sp alpha I/74) that is characterized by a decrease in content of the 80,000-dalton peptide and an increase in concentration of the 74,000-dalton peptide. The mother's spectrin digests show a decrease in the amount of 80,000-dalton peptide and the formation of new peptides of 61,000, 55,000, 21,000, and 16,000 daltons. The data indicate that this severe form of HPP is due to the inheritance of two distinct abnormal spectrins, Sp alpha I/74 and a new spectrin mutant, Sp alpha I/61.

Gli stili APA, Harvard, Vancouver, ISO e altri

32

Lawler, J., TL Coetzer, VN Mankad, RB Moore, JT Prchal e J. Palek. "Spectrin-alpha I/61: a new structural variant of alpha-spectrin in a double-heterozygous form of hereditary pyropoikilocytosis". Blood 72, n. 4 (1 ottobre 1988): 1412–15. http://dx.doi.org/10.1182/blood.v72.4.1412.bloodjournal7241412.

Testo completo

Abstract (sommario):

Recent biochemical studies have led to the identification of abnormal spectrins in the erythrocytes of patients with hereditary pyropoikilocytosis (HPP) and hereditary elliptocytosis (HE). In this report we describe the biochemical characterization of the erythrocytes from a proband with severe HPP who is doubly heterozygous for two mutant spectrins (Sp): Sp alpha I/74 and a new, previously undetected, mutant of alpha-spectrin designated Sp alpha I/61. The proband's erythrocytes are unstable when exposed to 45 degrees C, and her membrane skeletons exhibit instability to shear stress. The content of spectrin in the proband's erythrocyte membranes is decreased to 75% of control values. The amount of spectrin dimers in crude 4 degrees C spectrin extracts is increased (58%) as compared with control values (6% +/- 4%). Limited tryptic digestion reveals a marked decrease in the normal 80,000-dalton alpha I domain, an increase in the 74,000-dalton fragment that is characteristic of Sp alpha I/74, and an increase in a series of new fragments of 61,000, 55,000, 21,000, and 16,000 daltons. Both parents are asymptomatic, but they have increased amounts of spectrin dimers (17% to 25%). Limited tryptic digestion of the father's spectrin demonstrates the presence of a previously identified abnormal spectrin (Sp alpha I/74) that is characterized by a decrease in content of the 80,000-dalton peptide and an increase in concentration of the 74,000-dalton peptide. The mother's spectrin digests show a decrease in the amount of 80,000-dalton peptide and the formation of new peptides of 61,000, 55,000, 21,000, and 16,000 daltons. The data indicate that this severe form of HPP is due to the inheritance of two distinct abnormal spectrins, Sp alpha I/74 and a new spectrin mutant, Sp alpha I/61.

Gli stili APA, Harvard, Vancouver, ISO e altri

33

Nicolas, Gaël, Catherine M. Fournier, Colette Galand, Laurence Malbert-Colas, Odile Bournier, Yolande Kroviarski, Monique Bourgeois et al. "Tyrosine Phosphorylation Regulates Alpha II Spectrin Cleavage by Calpain". Molecular and Cellular Biology 22, n. 10 (15 maggio 2002): 3527–36. http://dx.doi.org/10.1128/mcb.22.10.3527-3536.2002.

Testo completo

Abstract (sommario):

ABSTRACT Spectrins, components of the membrane skeleton, are implicated in various cellular functions. Understanding the diversity of these functions requires better characterization of the interacting domains of spectrins, such as the SH3 domain. Yeast two-hybrid screening of a kidney cDNA library revealed that the SH3 domain of αII-spectrin binds specifically isoform A of low-molecular-weight phosphotyrosine phosphatase (LMW-PTP). The αII-spectrin SH3 domain does not interact with LMW-PTP B or C nor does LMW-PTP A interact with the αI-spectrin SH3 domain. The interaction of spectrin with LMW-PTP A led us to look for a tyrosine-phosphorylated residue in αII-spectrin. Western blotting showed that αII-spectrin is tyrosine phosphorylated in vivo. Using mutagenesis on recombinant peptides, we identified the residue Y1176 located in the calpain cleavage site of αII-spectrin, near the SH3 domain, as an in vitro substrate for Src kinase and LMW-PTP A. This Y1176 residue is also an in vivo target for kinases and phosphatases in COS cells. Phosphorylation of this residue decreases spectrin sensitivity to calpain in vitro. Similarly, the presence of phosphatase inhibitors in cell culture is associated with the absence of spectrin cleavage products. This suggests that the Y1176 phosphorylation state could modulate spectrin cleavage by calpain and may play an important role during membrane skeleton remodeling.

Gli stili APA, Harvard, Vancouver, ISO e altri

34

Higgs, Henry N. "Spectres of spectrin: molecular modeling and hemolytic disease". Trends in Biochemical Sciences 26, n. 12 (dicembre 2001): 702. http://dx.doi.org/10.1016/s0968-0004(01)02004-7.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

35

Hanspal, M., e J. Palek. "Synthesis and assembly of membrane skeletal proteins in mammalian red cell precursors." Journal of Cell Biology 105, n. 3 (1 settembre 1987): 1417–24. http://dx.doi.org/10.1083/jcb.105.3.1417.

Testo completo

Abstract (sommario):

The synthesis of membrane skeletal proteins in avian nucleated red cells has been the subject of extensive investigation, whereas little is known about skeletal protein synthesis in bone marrow erythroblasts and peripheral blood reticulocytes in mammals. To address this question, we have isolated nucleated red cell precursors and reticulocytes from spleens and from the peripheral blood, respectively, of rats with phenylhydrazine-induced hemolytic anemia and pulse-labeled them with [35S]methionine. Pulse-labeling of nucleated red cell precursors shows that the newly synthesized alpha- and beta-spectrins are present in the cytosol, with a severalfold excess of alpha-spectrin over beta-spectrin. However, in the membrane-skeletal fraction, newly synthesized alpha- and beta-spectrins are assembled in stoichiometric amounts, suggesting that the association of alpha-spectrin with the membrane skeleton may be rate-limited by the amount of beta-spectrin synthesized, as has been shown recently in avian erythroid cells (Blikstad, I., W. J. Nelson, R. T. Moon, and E. Lazarides, 1983. Cell, 32:1081-1091). Pulse-chase experiments in the rat nucleated red cell precursors show that the newly synthesized alpha- and beta-spectrin of the cytosol turn over coordinately and extremely rapidly. In contrast, in the membrane-skeletal fraction, the newly synthesized polypeptides of spectrin are stable. In contrast to nucleated erythroid cells, in reticulocytes the synthesis of alpha- and beta-spectrins is markedly diminished compared with the synthesis and assembly of proteins comigrating with bands 2.1 and 4.1 on SDS gels. Thus, in nucleated red cell precursors, the newly synthesized spectrin may be attached to the plasma membrane before proteins 2.1 and 4.1 are completely synthesized and incorporated in the membrane.

Gli stili APA, Harvard, Vancouver, ISO e altri

36

Pjotr Stoevelaar, L., Jonas Berzinš, Fabrizio Silvestri, Stefan Fasold, Khosro Zangeneh Kamali, Heiko Knopf, Falk Eilenberger et al. "Nanostructure-modulated planar high spectral resolution spectro-polarimeter". Optics Express 28, n. 14 (22 giugno 2020): 19818. http://dx.doi.org/10.1364/oe.392536.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

37

Baines, Anthony J. "Evolution of spectrin function in cytoskeletal and membrane networks". Biochemical Society Transactions 37, n. 4 (22 luglio 2009): 796–803. http://dx.doi.org/10.1042/bst0370796.

Testo completo

Abstract (sommario):

Spectrin is a cytoskeletal protein thought to have descended from an α-actinin-like ancestor. It emerged during evolution of animals to promote integration of cells into tissues by assembling signalling and cell adhesion complexes, by enhancing the mechanical stability of membranes and by promoting assembly of specialized membrane domains. Spectrin functions as an (αβ[H])2 tetramer that cross-links transmembrane proteins, membrane lipids and the actin cytoskeleton, either directly or via adaptor proteins such as ankyrin and 4.1. In the present paper, I review recent findings on the origins and adaptations in this system. (i) The genome of the choanoflagellate Monosiga brevicollis encodes α-, β- and βHeavy-spectrin, indicating that spectrins evolved in the immediate unicellular precursors of animals. (ii) Ankyrin and 4.1 are not encoded in that genome, indicating that spectrin gained function during subsequent animal evolution. (iii) Protein 4.1 gained a spectrin-binding activity in the evolution of vertebrates. (iv) Interaction of chicken or mammal β-spectrin with PtdInsP2 can be regulated by differential mRNA splicing, which can eliminate the PH (pleckstrin homology) domain in βI- or βII-spectrins; in the case of mammalian βII-spectrin, the alternative C-terminal region encodes a phosphorylation site that regulates interaction with α-spectrin. (v) In mammalian evolution, the single pre-existing α-spectrin gene was duplicated, and one of the resulting pair (αI) neo-functionalized for rapid make-and-break of tetramers. I hypothesize that the elasticity of mammalian non-nucleated erythrocytes depends on the dynamic rearrangement of spectrin dimers/tetramers under the shearing forces experienced in circulation.

Gli stili APA, Harvard, Vancouver, ISO e altri

38

Coleman, T. R., A. S. Harris, S. M. Mische, M. S. Mooseker e J. S. Morrow. "Beta spectrin bestows protein 4.1 sensitivity on spectrin-actin interactions." Journal of Cell Biology 104, n. 3 (1 marzo 1987): 519–26. http://dx.doi.org/10.1083/jcb.104.3.519.

Testo completo

Abstract (sommario):

The ability of protein 4.1 to stimulate the binding of spectrin to F-actin has been compared by cosedimentation analysis for three avian (erythrocyte, brain, and brush border) and two mammalian (erythrocyte and brain) spectrin isoforms. Human erythroid protein 4.1 stimulated actin binding of all spectrins except the brush border isoform (TW 260/240). These results suggested that the beta subunit determined the protein 4.1 sensitivity of the heterodimer, since all avian alpha subunits are encoded by a single gene. Tissue-specific posttranslational modification of the alpha subunit was excluded by examining the properties of hybrid spectrins composed of the purified alpha subunit from avian erythrocyte or brush border spectrin and the beta subunit of human erythrocyte spectrin. A hybrid composed of avian brush border alpha and human erythroid beta spectrin ran on nondenaturing gels as a discrete band, migrating near human erythroid spectrin tetramers. The actin-binding activity of this hybrid was stimulated by protein 4.1, while either chain alone was devoid of activity. Therefore, although both subunits were required for actin binding, the sensitivity of the spectrin-actin interaction to protein 4.1 is a property uniquely bestowed on the heterodimer by the beta subunit. The singular insensitivity of brush border spectrin to stimulation by erythroid protein 4.1 was also consistent with the absence of proteins in avian intestinal epithelial cells which were immunoreactive with polyclonal antisera sensitive to all of the known avian and human erythroid 4.1 isoforms.

Gli stili APA, Harvard, Vancouver, ISO e altri

39

Kennedy, S. P., S. L. Warren, B. G. Forget e J. S. Morrow. "Ankyrin binds to the 15th repetitive unit of erythroid and nonerythroid beta-spectrin." Journal of Cell Biology 115, n. 1 (1 ottobre 1991): 267–77. http://dx.doi.org/10.1083/jcb.115.1.267.

Testo completo

Abstract (sommario):

Ankyrin mediates the attachment of spectrin to transmembrane integral proteins in both erythroid and nonerythroid cells by binding to the beta-subunit of spectrin. Previous studies using enzymatic digestion, 2-nitro-5-thiocyanobenzoic acid cleavage, and rotary shadowing techniques have placed the spectrin-ankyrin binding site in the COOH-terminal third of beta-spectrin, but the precise site is not known. We have used a glutathione S-transferase prokaryotic expression system to prepare recombinant erythroid and nonerythroid beta-spectrin from cDNA encoding approximately the carboxy-terminal half of these proteins. Recombinant spectrin competed on an equimolar basis with 125I-labeled native spectrin for binding to erythrocyte membrane vesicles (IOVs), and also bound ankyrin in vitro as measured by sedimentation velocity experiments. Although full length beta-spectrin could inhibit all spectrin binding to IOVs, recombinant beta-spectrin encompassing the complete ankyrin binding domain but lacking the amino-terminal half of the molecule failed to inhibit about 25% of the binding capacity of the IOVs, suggesting that the ankyrin-independent spectrin membrane binding site must lie in the amino-terminal half of beta-spectrin. A nested set of shortened recombinants was generated by nuclease digestion of beta-spectrin cDNAs from ankyrin binding constructs. These defined the ankyrin binding domain as encompassing the 15th repeat unit in both erythroid and nonerythroid beta-spectrin, amino acid residues 1,768-1,898 in erythroid beta-spectrin. The ankyrin binding repeat unit is atypical in that it lacks the conserved tryptophan at position 45 (1,811) within the repeat and contains a nonhomologous 43 residue segment in the terminal third of the repeat. It also appears that the first 30 residues of this repeat, which are highly conserved between the erythroid and nonerythroid beta-spectrins, are critical for ankyrin binding activity. We hypothesize that ankyrin binds directly to the nonhomologous segment in the 15th repeat unit of both erythroid and nonerythroid beta-spectrin, but that this sequence must be presented in the context of a properly folded spectrin "repeat unit" structure. Future studies will identify which residues within the repeat unit are essential for activity, and which residues determine the specificity of various spectrins for different forms of ankyrin.

Gli stili APA, Harvard, Vancouver, ISO e altri

40

Wang Qian, 王倩, 赵江山 Zhao Jiangshan, 郭馨 Guo Xin, 范元媛 Fan Yuanyuan, 周翊 Zhou Yi e 江锐 Jiang Rui. "光刻用准分子激光器光谱控制中温度分布对输出光谱影响特性分析". Laser & Optoelectronics Progress 58, n. 9 (2021): 0914003. http://dx.doi.org/10.3788/lop202158.0914003.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

41

Depireux, Didier A., Jonathan Z. Simon, David J. Klein e Shihab A. Shamma. "Spectro-Temporal Response Field Characterization With Dynamic Ripples in Ferret Primary Auditory Cortex". Journal of Neurophysiology 85, n. 3 (1 marzo 2001): 1220–34. http://dx.doi.org/10.1152/jn.2001.85.3.1220.

Testo completo

Abstract (sommario):

To understand the neural representation of broadband, dynamic sounds in primary auditory cortex (AI), we characterize responses using the spectro-temporal response field (STRF). The STRF describes, predicts, and fully characterizes the linear dynamics of neurons in response to sounds with rich spectro-temporal envelopes. It is computed from the responses to elementary “ripples,” a family of sounds with drifting sinusoidal spectral envelopes. The collection of responses to all elementary ripples is the spectro-temporal transfer function. The complex spectro-temporal envelope of any broadband, dynamic sound can expressed as the linear sum of individual ripples. Previous experiments using ripples with downward drifting spectra suggested that the transfer function is separable, i.e., it is reducible into a product of purely temporal and purely spectral functions. Here we measure the responses to upward and downward drifting ripples, assuming reparability within each direction, to determine if the total bidirectional transfer function is fully separable. In general, the combined transfer function for two directions is not symmetric, and hence units in AI are not, in general, fully separable. Consequently, many AI units have complex response properties such as sensitivity to direction of motion, though most inseparable units are not strongly directionally selective. We show that for most neurons, the lack of full separability stems from differences between the upward and downward spectral cross-sections but not from the temporal cross-sections; this places strong constraints on the neural inputs of these AI units.

Gli stili APA, Harvard, Vancouver, ISO e altri

42

Zhou, Daixing, Jeanine A. Ursitti e Robert J. Bloch. "Developmental Expression of Spectrins in Rat Skeletal Muscle". Molecular Biology of the Cell 9, n. 1 (gennaio 1998): 47–61. http://dx.doi.org/10.1091/mbc.9.1.47.

Testo completo

Abstract (sommario):

Skeletal muscle contains spectrin (or spectrin I) and fodrin (or spectrin II), members of the spectrin supergene family. We used isoform-specific antibodies and cDNA probes to investigate the molecular forms, developmental expression, and subcellular localization of the spectrins in skeletal muscle of the rat. We report that β-spectrin (βI) replaces β-fodrin (βII) at the sarcolemma as skeletal muscle fibers develop. As a result, adult muscle fibers contain only α-fodrin (αII) and the muscle isoform of β-spectrin (βIΣ2). By contrast, other types of cells present in skeletal muscle tissue, including blood vessels and nerves, contain only α- and β-fodrin. During late embryogenesis and early postnatal development, skeletal muscle fibers contain a previously unknown form of spectrin complex, consisting of α-fodrin, β-fodrin, and the muscle isoform of β-spectrin. These complexes associate with the sarcolemma to form linear membrane skeletal structures that otherwise resemble the structures found in the adult. Our results suggest that the spectrin-based membrane skeleton of muscle fibers can exist in three distinct states during development.

Gli stili APA, Harvard, Vancouver, ISO e altri

43

Dubreuil, R. R., T. J. Byers, A. L. Sillman, D. Bar-Zvi, L. S. Goldstein e D. Branton. "The complete sequence of Drosophila alpha-spectrin: conservation of structural domains between alpha-spectrins and alpha-actinin." Journal of Cell Biology 109, n. 5 (1 novembre 1989): 2197–205. http://dx.doi.org/10.1083/jcb.109.5.2197.

Testo completo

Abstract (sommario):

We report the complete sequence of Drosophila alpha-spectrin and show that it is similar to vertebrate nonerythroid spectrins. As in vertebrates, the alpha subunit consists of two large domains of repetitive sequence (segments 1-9 and 11-19) separated by a short nonrepetitive sequence (segment 10). The 106-residue repetitive segments are defined by a consensus sequence of 54 residues. Chicken alpha-spectrin (Wasenius, V.-M., M. Saraste, P. Salven, M. Eramaa, L. Holm, V.-P. Lehto. 1989. J. Cell Biol. 108:79-93) shares 50 of these consensus positions. Through comparison of spectrin and alpha-actinin sequences, we describe a second lineage of spectrin segments (20 and 21) that differs from the 106-residue segments by an 8-residue insertion and by lack of many of the consensus residues. We present a model of spectrin evolution in which the repetitive lineage of spectrin segments and the nonrepetitive lineage of segments found in spectrin and alpha-actinin arose by separate multiplication events.

Gli stili APA, Harvard, Vancouver, ISO e altri

44

Narne, Vijaya Kumar, Mridula Sharma, Bram Van Dun, Shalini Bansal, Latika Prabhu e Brian C. J. Moore. "Effects of spectral smearing on performance of the spectral ripple and spectro-temporal ripple tests". Journal of the Acoustical Society of America 140, n. 6 (dicembre 2016): 4298–306. http://dx.doi.org/10.1121/1.4971419.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

45

Dubreuil, R. R., T. J. Byers, C. T. Stewart e D. P. Kiehart. "A beta-spectrin isoform from Drosophila (beta H) is similar in size to vertebrate dystrophin." Journal of Cell Biology 111, n. 5 (1 novembre 1990): 1849–58. http://dx.doi.org/10.1083/jcb.111.5.1849.

Testo completo

Abstract (sommario):

Spectrins are a major component of the membrane skeleton in many cell types where they are thought to contribute to cell form and membrane organization. Diversity among spectrin isoforms, especially their beta subunits, is associated with diversity in cell shape and membrane architecture. Here we describe a spectrin isoform from Drosophila that consists of a conventional alpha spectrin subunit complexed with a novel high molecular weight beta subunit (430 kD) that we term beta H. The native alpha beta H molecule binds actin filaments with high affinity and has a typical spectrin morphology except that it is longer than most other spectrin isoforms and includes two knoblike structures that are attributed to a unique domain of the beta H subunit. Beta H is encoded by a different gene than the previously described Drosophila beta-spectrin subunit but shows sequence similarity to beta-spectrin as well as vertebrate dystrophin, a component of the membrane skeleton in muscle. By size and sequence similarity, dystrophin is more similar to this newly described beta-spectrin isoform (beta H) than to other members of the spectrin gene family such as alpha-spectrin and alpha-actinin.

Gli stili APA, Harvard, Vancouver, ISO e altri

46

Schmidt, Burkhard C., Peer-Lennart Gehlken e Michael E. Böttcher. "Vibrational spectra of BaMn(CO3)2 and a re-analysis of the Raman spectrum of BaMg(CO3)2". European Journal of Mineralogy 25, n. 2 (12 giugno 2013): 137–44. http://dx.doi.org/10.1127/0935-1221/2013/0025-2272.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

47

Lehnert, M. E., e H. F. Lodish. "Unequal synthesis and differential degradation of alpha and beta spectrin during murine erythroid differentiation." Journal of Cell Biology 107, n. 2 (1 agosto 1988): 413–26. http://dx.doi.org/10.1083/jcb.107.2.413.

Testo completo

Abstract (sommario):

Murine erythroleukemia (MEL) cells represent a valuable system to study the biogenesis of the cytoskeleton during erythroid differentiation. When attached to fibronectin-coated dishes MEL cells induce, upon addition of DMSO, a 7-d differentiation process during which they enucleate and reach the reticulocyte stage (Patel, V. P., and H. F. Lodish. 1987. J. Cell Biol. 105:3105-3118); they accumulate band 3, spectrin, and ankyrin in amounts equivalent to those found in mature red blood cells. To follow the biosynthesis of spectrin during differentiation, membranes and cytoskeletal proteins of cells metabolically labeled with [35S]methionine were solubilized by SDS and alpha and beta spectrins were recovered by specific immunoadsorption. In both uninduced and 3-d induced cells, the relative synthesis of alpha/beta spectrin is approximately 1:3. In uninduced MEL cells newly synthesized alpha and beta spectrins are degraded with a similar half-life of approximately 10 h. In contrast, in 3-d differentiated MEL cells newly made beta spectrin is much more unstable than alpha spectrin; the half-lives of alpha and beta spectrin chains are approximately 22 and 8 h, respectively. Thus, accumulation of equal amounts of alpha and beta spectrin is caused by unequal synthesis and unequal degradation. As judged by Northern blot analyses, the level of actin mRNA is relatively constant throughout the 7-d differentiation period. alpha and beta spectrin mRNAs are barely detectable in uninduced cells, increase during the first 4 d of induction, and remain constant thereafter. In contrast, band 3 mRNA is first detectable on day 4 of differentiation. Thus, most of the spectrin that accumulates in enucleating reticulocytes is synthesized during the last few days of erythropoiesis, concomitant with the onset of band 3 synthesis. To determine whether this was occurring in normal mouse erythropoiesis, we analyzed the rate of appearance of labeled membrane proteins in mature erythrocytes after a single injection of [35S]methionine. Our results show that most of the spectrin and band 3 in mature erythrocytes is synthesized during the last days of bone marrow erythropoiesis, and that, in the marrow, band 3 and protein 4.1 are synthesized at a somewhat later stage of development than are alpha and beta spectrin, ankyrin, and actin.

Gli stili APA, Harvard, Vancouver, ISO e altri

48

Tao, Chen, Chunsheng Li, Yingchao Li, Hongxia Wang, Yaru Zhang, Zhiheng Zhou, Xuefei Mao, Zhenyu Ma e Di Tian. "Correction: A UV digital micromirror spectrometer for dispersive AFS: spectral interference in simultaneous determination of Se and Pb". Journal of Analytical Atomic Spectrometry 34, n. 2 (2019): 413–14. http://dx.doi.org/10.1039/c8ja90055h.

Testo completo

Abstract (sommario):

Correction for ‘A UV digital micromirror spectrometer for dispersive AFS: spectral interference in simultaneous determination of Se and Pb’ by Chen Tao et al., J. Anal. At. Spectrom., 2018, 33, 2098–2106.

Gli stili APA, Harvard, Vancouver, ISO e altri

49

Martin, Michael C., Charlotte Dabat-Blondeau, Miriam Unger, Julia Sedlmair, Dilworth Y. Parkinson, Hans A. Bechtel, Barbara Illman et al. "3D spectral imaging with synchrotron Fourier transform infrared spectro-microtomography". Nature Methods 10, n. 9 (4 agosto 2013): 861–64. http://dx.doi.org/10.1038/nmeth.2596.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

50

Schneider, A., H. U. Lutz, R. Marugg, P. Gehr e T. Seebeck. "Spectrin-like proteins in the paraflagellar rod structure of Trypanosoma brucei". Journal of Cell Science 90, n. 2 (1 giugno 1988): 307–15. http://dx.doi.org/10.1242/jcs.90.2.307.

Testo completo

Abstract (sommario):

A polyclonal, monospecific rabbit antibody to human erythrocyte spectrins cross-reacted with two sets of proteins (a doublet of 180/200K and a triplet of 67–66-65K; K = 10(3) Mr) in the parasitic protozoon Trypanosoma brucei brucei. Except for the 66K protein, the cross-reacting proteins are localized in the flagellum, on the basis of evidence from cell fractionation and immunofluorescence microscopy. Immunogold labelling and electron micrographs further revealed that the spectrin-like proteins are confined to the paraflagellar rod structure. The spectrin-like proteins with apparent molecular weights of 180 and 200 share homology with spectrin band 1, since V8-protease from Staphylococcus aureus generated similarly sized, antigenic peptides from these proteins. The results indicate homology between the cross-reacting proteins and human red cell spectrin.

Gli stili APA, Harvard, Vancouver, ISO e altri

Articoli di riviste sul tema "Spectron"

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili