51 research outputs found
Demonstration of near infrared gas sensing using gold nanodisks on functionalized silicon
No full textThis paper was published in OPTICS EXPRESS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.19.007664. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law[EN] In this work, we demonstrate experimentally the use of an array of gold nanodisks on functionalized silicon for chemosensing purposes. The metallic nanostructures are designed to display a very strong plasmonic resonance in the infrared regime, which results in highly sensitive sensing. Unlike usual experiments which are based on the functionalization of the metal surface, we functionalized here the silicon substrate. This silicon surface was modified chemically by buildup of an organosilane self-assembled monolayer (SAM) containing isocyanate as functional group. These groups allow for an easy surface regeneration by simple heating, thanks to the thermally reversible interaction isocyanate-analyte, which allows the cyclic use of the sensor. The technique showed a high sensitivity to surface binding events in gas and allowed the surface regeneration by heating of the sensor at 150°C. A relative wavelength shift ¿¿max/¿0 = 0.027 was obtained when the saturation level was reached. © 2011 Optical Society of America.Financial support by the Spanish MICINN under contracts CONSOLIDER EMET (CSD2008-00066) and TEC2008-06871-C02-02 and European Commission FP7 under the FET-Open project TAILPHOX 233833 is gratefully acknowledged.Rodríguez Cantó, PJ.; Martínez Marco, ML.; Rodríguez Fortuño, FJ.; Tomás Navarro, B.; Ortuño Molinero, R.; Peransi Llopis, SM.; Martínez Abietar, AJ. (2011). Demonstration of near infrared gas sensing using gold nanodisks on functionalized silicon. Optics Express. 19(8):7664-7672. https://doi.org/10.1364/OE.19.007664S76647672198Barnes, W. L., Dereux, A., & Ebbesen, T. W. (2003). Surface plasmon subwavelength optics. Nature, 424(6950), 824-830. doi:10.1038/nature01937Maier, S. A., Brongersma, M. L., Kik, P. G., Meltzer, S., Requicha, A. A. G., & Atwater, H. A. (2001). Plasmonics-A Route to Nanoscale Optical Devices. Advanced Materials, 13(19), 1501-1505. doi:10.1002/1521-4095(200110)13:193.0.co;2-zLink, S., & El-Sayed, M. A. (2003). OPTICALPROPERTIES ANDULTRAFASTDYNAMICS OFMETALLICNANOCRYSTALS. Annual Review of Physical Chemistry, 54(1), 331-366. doi:10.1146/annurev.physchem.54.011002.103759Willets, K. A., & Van Duyne, R. P. (2007). Localized Surface Plasmon Resonance Spectroscopy and Sensing. Annual Review of Physical Chemistry, 58(1), 267-297. doi:10.1146/annurev.physchem.58.032806.104607Anker, J. N., Hall, W. P., Lyandres, O., Shah, N. C., Zhao, J., & Van Duyne, R. P. (2008). Biosensing with plasmonic nanosensors. Nature Materials, 7(6), 442-453. doi:10.1038/nmat2162Zhao, J., Zhang, X., Yonzon, C. R., Haes, A. J., & Van Duyne, R. P. (2006). Localized surface plasmon resonance biosensors. Nanomedicine, 1(2), 219-228. doi:10.2217/17435889.1.2.219SHANKARAN, D., GOBI, K., & MIURA, N. (2007). Recent advancements in surface plasmon resonance immunosensors for detection of small molecules of biomedical, food and environmental interest. Sensors and Actuators B: Chemical, 121(1), 158-177. doi:10.1016/j.snb.2006.09.014Miura, N., Ogata, K., Sakai, G., Uda, T., & Yamazoe, N. (1997). Detection of Morphine in ppb Range by Using SPR (Surface- Plasmon-Resonance) Immunosensor. Chemistry Letters, 26(8), 713-714. doi:10.1246/cl.1997.713Shankaran, D. R., Matsumoto, K., Toko, K., & Miura, N. (2006). Development and comparison of two immunoassays for the detection of 2,4,6-trinitrotoluene (TNT) based on surface plasmon resonance. Sensors and Actuators B: Chemical, 114(1), 71-79. doi:10.1016/j.snb.2005.04.013Cosnier, S. (1999). Biomolecule immobilization on electrode surfaces by entrapment or attachment to electrochemically polymerized films. A review. Biosensors and Bioelectronics, 14(5), 443-456. doi:10.1016/s0956-5663(99)00024-xLee, J. W., Sim, S. J., Cho, S. M., & Lee, J. (2005). Characterization of a self-assembled monolayer of thiol on a gold surface and the fabrication of a biosensor chip based on surface plasmon resonance for detecting anti-GAD antibody. Biosensors and Bioelectronics, 20(7), 1422-1427. doi:10.1016/j.bios.2004.04.017Mark, S. S., Sandhyarani, N., Zhu, C., Campagnolo, C., & Batt, C. A. (2004). Dendrimer-Functionalized Self-Assembled Monolayers as a Surface Plasmon Resonance Sensor Surface. Langmuir, 20(16), 6808-6817. doi:10.1021/la0495276Kato, K., Dooling, C. M., Shinbo, K., Richardson, T. H., Kaneko, F., Tregonning, R., … Hunter, C. A. (2002). Surface plasmon resonance properties and gas response in porphyrin Langmuir–Blodgett films. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 198-200, 811-816. doi:10.1016/s0927-7757(01)01006-8Senaratne, W., Andruzzi, L., & Ober, C. K. (2005). Self-Assembled Monolayers and Polymer Brushes in Biotechnology: Current Applications and Future Perspectives. Biomacromolecules, 6(5), 2427-2448. doi:10.1021/bm050180aStewart, M. E., Anderton, C. R., Thompson, L. B., Maria, J., Gray, S. K., Rogers, J. A., & Nuzzo, R. G. (2008). Nanostructured Plasmonic Sensors. Chemical Reviews, 108(2), 494-521. doi:10.1021/cr068126nYin, L., Liu, Y., Ke, Z., & Yin, J. (2009). Preparation of a blocked isocyanate compound and its grafting onto styrene-b-(ethylene-co-1-butene)-b-styrene triblock copolymer. European Polymer Journal, 45(1), 191-198. doi:10.1016/j.eurpolymj.2008.10.016Suyama, K., Iriyama, H., Shirai, M., & Tsunooka, M. (2001). Curing Systems Using Photolysis of Carbomoyloxyimino Groups and Themally Regenerated Isocyanate Groups. Journal of Photopolymer Science and Technology, 14(2), 155-158. doi:10.2494/photopolymer.14.155Patskovsky, S., Kabashin, A. V., Meunier, M., & Luong, J. H. T. (2004). Near-infrared surface plasmon resonance sensing on a silicon platform. Sensors and Actuators B: Chemical, 97(2-3), 409-414. doi:10.1016/j.snb.2003.09.023Shelton, D. J., Peters, D. W., Sinclair, M. B., Brener, I., Warne, L. K., Basilio, L. I., … Boreman, G. D. (2010). Effect of thin silicon dioxide layers on resonant frequency in infrared metamaterials. Optics Express, 18(2), 1085. doi:10.1364/oe.18.001085Bhalla, V., Carrara, S., Stagni, C., & Samorì, B. (2010). Chip cleaning and regeneration for electrochemical sensor arrays. Thin Solid Films, 518(12), 3360-3366. doi:10.1016/j.tsf.2009.10.022Malinsky, M. D., Kelly, K. L., Schatz, G. C., & Van Duyne, R. P. (2001). Chain Length Dependence and Sensing Capabilities of the Localized Surface Plasmon Resonance of Silver Nanoparticles Chemically Modified with Alkanethiol Self-Assembled Monolayers. Journal of the American Chemical Society, 123(7), 1471-1482. doi:10.1021/ja003312aSpencer, M. J. S., & Nyberg, G. L. (2004). Adsorption of silane and methylsilane on gold surfaces. Surface Science, 573(2), 151-168. doi:10.1016/j.susc.2004.08.043Gradess, R., Abargues, R., Habbou, A., Canet-Ferrer, J., Pedrueza, E., Russell, A., … Martínez-Pastor, J. P. (2009). Localized surface plasmon resonance sensor based on Ag-PVA nanocomposite thin films. Journal of Materials Chemistry, 19(48), 9233. doi:10.1039/b910020bBrolo, A. G., Gordon, R., Leathem, B., & Kavanagh, K. L. (2004). Surface Plasmon Sensor Based on the Enhanced Light Transmission through Arrays of Nanoholes in Gold Films. Langmuir, 20(12), 4813-4815. doi:10.1021/la0493621MAURIZ, E., CALLE, A., MONTOYA, A., & LECHUGA, L. (2006). Determination of environmental organic pollutants with a portable optical immunosensor. Talanta, 69(2), 359-364. doi:10.1016/j.talanta.2005.09.049Yu, Q., Chen, S., Taylor, A. D., Homola, J., Hock, B., & Jiang, S. (2005). Detection of low-molecular-weight domoic acid using surface plasmon resonance sensor. Sensors and Actuators B: Chemical, 107(1), 193-201. doi:10.1016/j.snb.2004.10.064Cui, X. (2003). Real-time immunoassay of ferritin using surface plasmon resonance biosensor. Talanta, 60(1), 53-61. doi:10.1016/s0039-9140(03)00043-
Widespread Expression of BORIS/CTCFL in Normal and Cancer Cells
No full textThis is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
The Effect of a Scanning Nanosecond Laser Pulse Beam on the Microtopography of Ceramic Al2O3 Coatings
No full textAnalysis of endocytosis at eisosomes
No full textThe yeast plasma membrane contains at least three microdomains – membrane compartment containing Pma1 (MCP), membrane compartment containing TORC2 (MCT) and membrane compartment containing Can1 (MCC). Eisosomes underlie the MCC domain defined by the marker protein arginine permease (Can1). Eisosomes are large protein assemblies composed of Pil1 and Lsp1 proteins, of which Pil1 is essential for plasma membrane organization. We found that the uncharacterized AAA-ATPase protein Yta6 dynamically colocalizes with eisosomes. Yta6 physically interacts with eisosome components, specifically with Pil1. In PIL1 deletion cells, Yta6 is unable to localize normally to the plasma membrane. Yta6 foci colocalize with the intermediates of FM4-64 on the plasma membrane. The number of these intermediates is increased upon overexpression of Yta6. Overexpressed Yta6 is also able to rescue the defects of endocytosis in cells devoid of amphiphysins. Together rescue experiments and colocalization of a protein cargo Hxt3 with eisosomes suggest that Yta6 likely plays a role in endocytosis at eisosomes. To identify genes whose products function together with eisosome components, we independently carried out a genetic interaction study (epistatic mini array profile) which revealed the protein Emp70. EMP70 showed the strongest correlation in genetic profile with PIL1. Emp70 localizes to a subset of eisosomes in addition to its localization in endosomes and vacuoles. We found eisosomes are required for normal numbers of Emp70 plasma membrane foci. Deletion of Emp70 misdirected endosomal protein Kex2 to vacuole, implicating its essential role in maintaining the architecture of the endosomal compartment. In summary, Yta6 likely plays a role in initiation of endocytosis at eisosomes and Emp70 during intracellular trafficking from plasma membrane to vacuole
Avaliação do papel dos receptores B1 e B2 para as cininas na modulação da encefalomielite autoimune experimental
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas. Programa de Pós-Graduação em FarmacologiaA Esclerose Múltipla (EM) é uma doença inflamatória crônica e progressiva, a qual desencadeia desmielinização no sistema nervoso central (SNC). Apesar dos grandes avanços observados nas últimas décadas quanto aos mecanismos envolvidos no desenvolvimento e controle da EM, nenhum tratamento completamente seguro e eficaz surgiu até o presente momento. Estudos prévios demonstraram que os níveis de cininas, assim como a expressão dos seus respectivos receptores B1 e B2 encontram-se aumentados em pacientes com EM. No entanto, os mecanismos pelos quais os receptores de cininas regulam o desenvolvimento da EM não foram totalmente elucidados. Neste sentido, o presente estudo tem como objetivo investigar o papel desempenhado pelos receptores de cininas na modulação da encefalomielite autoimune experimental (EAE), o modelo clássico de EM. A EAE foi induzida em camundongos C57BL/6 fêmeas com inoculação de glicoproteína de mielina do oligodendrócitos (MOG35-55), associado com adjuvante incompleto de Freund (CFA), suplementado com Mycobacterium tuberculosis (Mt) H37Ra. Além disso, cada animal recebeu toxina pertussis por via intraperitoneal no dia 0 e dia 2. Neste modelo experimental, até o sétimo dia após a imunização, os linfócitos T reativos à MOG acumulam-se nos linfonodos inguinais. Entre os dias 10-12 surgem os primeiros sinais clínicos relacionados à doença, os quais atingem escore máximo entre os dias 15-18 após a imunização. Por esta razão durante o desenvolvimento deste trabalho definimos os dias 0-7 como a fase de indução da EAE, os dias 7-15 como fase aguda e por fim os dias 15-25 como a fase crônica da doença. O presente estudo demonstrou que o bloqueio dos receptores B1, tanto pelo tratamento farmacológico com o antagonista seletivo para o B1R - des-arg9-[leu8]-bradicinina (DALBK, 50 nmol/kg, i.p.) como em animais nocautes (B1R-/-), na fase de indução da EAE inibiu o desenvolvimento da doença por interferir com o surgimento da resposta imunológica periférica. De maneira significativa, o bloqueio do B1R inibiu a hiperalgesia mecânica induzida pela EAE durante os 14 dias após a imunização. Além disso, a administração do antagonista seletivo para o receptor B1 (DALBK) durante a fase de indução inibiu a produção e a expressão de citocinas e de fatores de transcrição relacionados com os linfócitos Th1 e Th17, tanto em órgãos periféricos como no SNC. Durante a fase crônica da EAE, o tratamento com o antagonista seletivo para o B1R (DALBK, 50 nmol/kg, i.p.) foi capaz de reduzir significantemente a progressão da doença. O tratamento com o antagonista seletivo para o B1R (DALBK), assim como o antagonista seletivo para o B2R (HOE-140) inibiu de maneira significativa a produção e a expressão de mediadores pró-inflamatórios em cultura primária de astrócitos estimulados com IFN-?. De maneira interessante, a administração do agonista seletivo para o receptor B1 (des-arg9- bradicinina, DABK, 300 nmol/kg, i.p.), durante a fase aguda da EAE bloqueou a instalação da doença e inibiu o aumento da permeabilidade da barreira hemato-encefálica (BHE) e conseqüentemente a neuroinflamação. Já o bloqueio do receptor B2 (antagonista HOE-140, 150 nmol/kg, i.p. e animal nocaute B2R-/-) durante todos os períodos de análises causou inibição parcial no desenvolvimento da EAE. Em resumo, nossos resultados sugerem que os receptores de cininas, principalmente o subtipo B1R apresenta um papel dual na progressão da EAE, dependendo da fase de tratamento, através da inibição dos linfócitos T auto-reativos e das células gliais
Arquitetura da paisagem da cidade: uma leitura da vegetação urbana inserida no sistema viário
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção.Estudar os espaços livres urbanos é a principal temática desta pesquisa. Os estudos são desenvolvidos dentro de um recorte, o qual recai sobre os espaços livres urbanos do sistema viário, centrando as preocupações para a configuração destes espaços livres pela inserção da vegetação. Desta maneira, tem-se como objetivo geral da pesquisa verificar como a vegetação inserida nos espaços livres urbanos do sistema viário constitui um elemento de desenho urbano apresentando uma etapa inicial de uma metodologia projetual em arquitetura paisagística que enfoque a fase de sistematização da análise do problema de projeto. A pesquisa foi conduzida com a abordagem da Arquitetura Paisagística e foram adotadas duas etapas bem distintas: revisão de literatura e pesquisa de campo. Na revisão de literatura pretendeu-se levantar os conceitos próprios da atividade da Arquitetura Paisagística encarando-a como disciplina projetual e associando-a ao Design Ambiental, necessitando, assim, de linhas metodológicas específicas para apresentação de soluções coerentes aos problemas paisagísticos. Sob esta ótica, reflexões sobre o uso da vegetação no projeto dos espaços exteriores são apresentadas através de croquis e imagens. Ao final da revisão de literatura apontou-se uma etapa de sistematização da análise do problema de projeto, dentro da abordagem da concepção de uma metodologia projetual em arquitetura paisagística. Na pesquisa de campo foram analisadas oito vias de circulação da área central de Florianópolis, Santa Catarina, Brasil, com o objetivo de caracterizar a vegetação inserida no sistema viário da área central de Florianópolis, analisando a inserção da vegetação nos espaços livres urbanos de um sistema viário. A pesquisa de campo também exemplificou a etapa de sistematização da análise do problema de projeto. Através de estudos sobre tipologias de espaços exteriores, formas de plantio da vegetação urbana, e fechamento proporcionado por esta vegetação, verificou-se a criação e definição de espaços exteriores distintos no desenho urbano
Renewable sustainable biocatalyzed electricity production in a photosynthetic algal microbial fuel cell (PAMFC)
No full textElectricity production via solar energy capturing by living higher plants and microalgae in combination with microbial fuel cells are attractive because these systems promise to generate useful energy in a renewable, sustainable, and efficient manner. This study describes the proof of principle of a photosynthetic algal microbial fuel cell (PAMFC) based on naturally selected algae and electrochemically active microorganisms in an open system and without addition of instable or toxic mediators. The developed solarpowered PAMFC produced continuously over 100 days renewable biocatalyzed electricity. The sustainable performance of the PAMFC resulted in a maximum current density of 539 mA/m2 projected anode surface area and a maximum power production of 110 mW/m2 surface area photobioreactor. The energy recovery of the PAMFC can be increased by optimization of the photobioreactor, by reducing the competition from non-electrochemically active microorganisms, by increasing the electrode surface and establishment of a further-enriched biofilm. Since the objective is to produce net renewable energy with algae, future research should also focus on the development of low energy input PAMFCs. This is because current algae production systems have energy inputs similar to the energy present in the outcoming valuable products
Insights into grand unified theories from current experimental data
No full textIn this thesis, we investigate several ways how the structure of a high energy particle physics model constituting a grand unification theory (GUT) in supersymmetry (SUSY) can be inferred from multiple types of information obtained at low energy.
First, we calculate the values and 1 sigma ranges of the running quark and lepton Yukawa couplings as well as of the quark mixing parameters at various energy scales to provide useful input for flavour model building in GUTs and other scenarios while including tan beta enhanced SUSY threshold corrections in a simple way.
Next, we analyse the naturalness of the Minimal Supersymmetric Standard Model (MSSM) in the light of the discovery of the Higgs boson at the Large Hadron Collider (LHC). In particular, we find that among possible departures from the constrained MSSM (cMSSM) non-universal gaugino masses represent the most promising way to find parameter regions with a fine-tuning of only O(10) even for a Higgs mass of about 126 GeV, compared to O(100) for the cMSSM. In this context, we also discuss the preference for certain GUT-scale Yukawa coupling ratios over others based on fine-tuning.
Following that, we study how also the recent determination of the leptonic mixing angle theta^pmns_13 can be accommodated in a simple scenario for GUT models of flavour via charged lepton corrections. This leads us to four conditions that can easily be implemented. In addition, the interplay of the value of theta^pmns_13 with future determinations of the Dirac CP phase delta^pmns is discussed using lepton mixing sum rules.
Finally, we study how the double missing partner mechanism as a solution to the doublet-triplet splitting problem can be incorporated into SU(5) GUT models of flavour to comply with the bounds on proton decay. In this context, we argue that the introduction of two adjoints of SU(5) is a compelling idea and calculate its constraints on the GUT scale and dimension five proton decay suppression scale at two loops. We close with general comments on the calculation of the proton lifetime in the considered scenario for flavour models.
Multiple appendices are included detailing non-obvious aspects of the calculation and other kinds of valuable information for GUT model building
Towards label-free biosensors based on localized surface plasmon resonance
No full textMedical diagnostics is in constant search of new tools and devices able to provide in short
time, accurate and versatile tests performed on patients. Nanotechnology has contributed
largely in developing biosensors of smaller size at a lower cost by using a minimal amount of
sample. Biosensors aim to monitor and diagnosticate “in situ” the patient status and the
diseases caused by alteration of the body metabolism by, for example, the detection of gene
mutations, alteration of gene expression or alteration of proteins.
The aim of this work is the development of biosensors that satisfy the requirements which are
critical for applications. A biosensor must be i) easy to use, ii) economically convenient, and
therefore preferentially label free, iii) highly sensitive, iv) reversible, v) and suitable for Point
of Care Testing, that is to be used ”in situ” on the patient.
We have focused on biosensors based on the optical properties of nanostructured metals as Au
or Ag, in particular by using on Localized Surface Plasmon Resonance (LSPR) spectroscopy.
Nanostructured metals under irradiation of electromagnetic wave (as light) exhibit intense
absorption bands as results of the localized electronic charges of the metal surface coming into
resonance with the incident energy. According to the Mie’s theory, the LSPR absorption band
feature changes when the refractive index of the media surrounding the metal nanostructures is
varied.
Of particular interest for our purpose are the possible changes of the LSPR band features taking
place under molecular interactions occurring at the nanostructures surfaces: the shift of LSPR
bands is the “transducer” of molecular interactions. These changes can be easily detected by
conventional UV-Vis spectroscopy, in transmittance mode.
While a large number of studies have been carried out on monodisperse nanoparticles
suspended in solution, gold nanoparticles (NPs) deposited on a transparent surface open the
possibility to fabricate biosensor based on multiplex array platforms. Nonetheless, one of the
major problems in using these plasmonic materials for biosensing purpose is related to the
stability of the metal NPs in different solvents and in particular in aqueous solutions.
In this study we demonstrate i) the possibility to achieve highly stable NPs by simple thermal
evaporation of Au on a substrate commercially available, the Fluorine Tin Oxide (FTO) (Chapter 2); ii) a reproducible variation of the LSPR bands under formation of organic selfassembled
monolayers (SAMs), iii) reversible changes in the features of the LSPR bands,
(Chapter 3), iv) a specific and reproducible LSPR band changes under molecular interactions
occurring at NPs surfaces, as DNA hybridization (Chapter 4).
This work demonstrates that the plasmonic material based on Au NPs deposited on FTO
surfaces represents a convenient platform for biosensors because of i) inexpensive fabrication,
ii) stability of this material in various solvent, including water, of, iii) the easy way to detect
the molecular interaction, and iv) the good sensitivity to molecular interactions
- …
