Plasmonic nanoparticle enhanced photocurrent in GaN/InGaN/GaN quantum well solar cells

We demonstrate enhanced external quantum efficiency and current-voltage characteristics due to scattering by 100 nm silver nanoparticles in a single 2.5 nm thick InGaN quantum well photovoltaic device. Nanoparticle arrays were fabricated on the surface of the device using an anodic alumina template masking process. The Ag nanoparticles increase light scattering, light trapping, and carrier collection in the III-N semiconductor layers leading to enhancement of the external quantum efficiency by up to 54%. Additionally, the short-circuit current in cells with 200 nm p-GaN emitter regions is increased by 6% under AM 1.5 illumination. AFORS-Het simulation software results were used to predict cell performance and optimize emitter layer thickness

The Abl and Arg non-receptor tyrosine kinases regulate different zones of stress fiber, focal adhesion, and contractile network localization in spreading fibroblasts

Directed cell migration requires precise spatial control of F-actin-based leading edge protrusion, focal adhesion (FA) dynamics, and actomyosin contractility. In spreading fibroblasts, the Abl family kinases, Abl and Arg, primarily localize to the nucleus and cell periphery, respectively. Here we provide evidence that Abl and Arg exert different spatial regulation on cellular contractile and adhesive structures. Loss of Abl function reduces FA, F-actin, and phosphorylated myosin light chain (pMLC) staining at the cell periphery, shifting the distribution of these elements more to the center of the cell than in wild-type (WT) and arg—/— cells. Conversely, loss of Arg function shifts the distribution of these contractile and adhesion elements more to the cell periphery relative to WT and abl—/— cells. Abl/Arg-dependent phosphorylation of p190RhoGAP (p190) promotes its binding to p120RasGAP (p120) to form a functional RhoA GTPase inhibitory complex, which attenuates RhoA activity and downstream pMLC and FA formation. p120 and p190 colocalize both in the central region and at the cell periphery in WT cells. This p120:p190 colocalization redistributes to a more peripheral distribution in abl—/— cells and to a more centralized distribution in arg—/— cells, and these altered distributions can be restored to WT patterns via re-expression of Abl or Arg, respectively. Thus, the altered p120:p190 distribution in the mutant cells correlates inversely with the redistribution in adhesions, actin, and pMLC staining in these cells. Our studies suggest that Abl and Arg exert different spatial regulation on actomyosin contractility and focal adhesions within cells

The Abl and Arg non-receptor tyrosine kinases regulate different zones of stress fiber, focal adhesion, and contractile network localization in spreading fibroblasts

Directed cell migration requires precise spatial control of F-actin-based leading edge protrusion, focal adhesion (FA) dynamics, and actomyosin contractility. In spreading fibroblasts, the Abl family kinases, Abl and Arg, primarily localize to the nucleus and cell periphery, respectively. Here we provide evidence that Abl and Arg exert different spatial regulation on cellular contractile and adhesive structures. Loss of Abl function reduces FA, F-actin, and phosphorylated myosin light chain (pMLC) staining at the cell periphery, shifting the distribution of these elements more to the center of the cell than in wild-type (WT) and arg—/— cells. Conversely, loss of Arg function shifts the distribution of these contractile and adhesion elements more to the cell periphery relative to WT and abl—/— cells. Abl/Arg-dependent phosphorylation of p190RhoGAP (p190) promotes its binding to p120RasGAP (p120) to form a functional RhoA GTPase inhibitory complex, which attenuates RhoA activity and downstream pMLC and FA formation. p120 and p190 colocalize both in the central region and at the cell periphery in WT cells. This p120:p190 colocalization redistributes to a more peripheral distribution in abl—/— cells and to a more centralized distribution in arg—/— cells, and these altered distributions can be restored to WT patterns via re-expression of Abl or Arg, respectively. Thus, the altered p120:p190 distribution in the mutant cells correlates inversely with the redistribution in adhesions, actin, and pMLC staining in these cells. Our studies suggest that Abl and Arg exert different spatial regulation on actomyosin contractility and focal adhesions within cells

A peptide photoaffinity probe specific for the active conformation of the Abl tyrosine kinase

The design of sensors to monitor the activity state of specific protein kinases is challenging due to the complexity of eukaryotic kinomes. Here we describe a peptide-based photaffinity probe that specifically labels the active conformation of the Abl tyrosine kinase

Disrupting Mediator with a Short Peptide Ligand

No AbstractPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56157/1/1233_ftp.pd

Increased Dendrite Branching in AβPP/PS1 Mice and Elongation of Dendrite Arbors by Fasudil Administration

Amyloid-β (Aβ) overproduction and dendrite arbor atrophy are hallmarks of Alzheimer’s disease. The RhoA GTPase (Rho) signals through Rho kinase (ROCK) to control cytoskeletal dynamics and regulate neuron structure. Hyperactive Rho signaling destabilizes neurons leading to dendritic regression that can be rescued by genetic or pharmacological reduction of ROCK signaling. To understand what effect reduced ROCK signaling has on the dendrite arbors of mice that overproduce Aβ, we administered the ROCK inhibitor fasudil to AβPP/PS1 transgenic mice. We report that increased dendrite branching occurs in AβPP/PS1 mice and that fasudil promotes lengthening of the dendrite arbors of CA1 pyramidal neurons

The Abl-related gene (Arg) requires its F-actin–microtubule cross-linking activity to regulate lamellipodial dynamics during fibroblast adhesion

Microtubules (MTs) help establish and maintain cell polarity by promoting actin-dependent membrane protrusion at the leading edge of the cell, but the molecular mechanisms that mediate cross-talk between actin and MTs during this process are unclear. We demonstrate that the Abl-related gene (Arg) nonreceptor tyrosine kinase is required for dynamic lamellipodial protrusions after adhesion to fibronectin. arg−/− fibroblasts exhibit reduced lamellipodial dynamics as compared with wild-type fibroblasts, and this defect can be rescued by reexpression of an Arg-yellow fluorescent protein fusion. We show that Arg can bind MTs with high affinity and cross-link filamentous actin (F-actin) bundles and MTs in vitro. MTs concentrate and insert into Arg-induced F-actin–rich cell protrusions. Arg requires both its F-actin–binding domains and its MT-binding domain to rescue the defects in lamellipodial dynamics of arg−/− fibroblasts. These findings demonstrate that Arg can mediate physical contact between F-actin and MTs at the cell periphery and that this cross-linking activity is required for Arg to regulate lamellipodial dynamics in fibroblasts

A Portable Dynamic Laser Speckle System for Sensing Long-Term Changes Caused by Treatments in Painting Conservation

[EN] Dynamic laser speckle (DLS) is used as a reliable sensor of activity for all types of materials. Traditional applications are based on high-rate captures (usually greater than 10 frames-per-second, fps). Even for drying processes in conservation treatments, where there is a high level of activity in the first moments after the application and slower activity after some minutes or hours, the process is based on the acquisition of images at a time rate that is the same in moments of high and low activity. In this work, we present an alternative approach to track the drying process of protective layers and other painting conservation processes that take a long time to reduce their levels of activity. We illuminate, using three different wavelength lasers, a temporary protector (cyclododecane) and a varnish, and monitor them using a low fps rate during long-term drying. The results are compared to the traditional method. This work also presents a monitoring method that uses portable equipment. The results present the feasibility of using the portable device and show the improved sensitivity of the dynamic laser speckle when sensing the long-term process for drying cyclododecane and varnish in conservation.This work was partially funded by Generalitat Valenciana project AICO/2016/058 and by the Plan Nacional de I+D, Comision Interministerial de Ciencia y Tecnologia (FEDER-CICYT) under the project HAR2013-47895-C2-1-P and project HAR2017-85557-PPérez Jiménez, AJ.; Gonzalez-Peña, RJ.; Braga, RJ.; Perles Ivars, A.; Pérez Marín, E.; García Diego, FJ. (2018). A Portable Dynamic Laser Speckle System for Sensing Long-Term Changes Caused by Treatments in Painting Conservation. Sensors. 18(1):1-13. https://doi.org/10.3390/s18010190S113181Kim, M. K. (2010). Principles and techniques of digital holographic microscopy. Journal of Photonics for Energy, 018005. doi:10.1117/6.0000006Yokota, M., Kawakami, T., Kimoto, Y., & Yamaguchi, I. (2011). Drying process in a solvent-based paint analyzed by phase-shifting digital holography and an estimation of time for tack free. Applied Optics, 50(30), 5834. doi:10.1364/ao.50.005834Yamaguchi, I., Ida, T., Yokota, M., & Kobayashi, K. (2007). Monitoring of Paint Drying Process by Phase-shifting Digital Holography. Adaptive Optics: Analysis and Methods/Computational Optical Sensing and Imaging/Information Photonics/Signal Recovery and Synthesis Topical Meetings on CD-ROM. doi:10.1364/dh.2007.dwc2Krzemień, L., Łukomski, M., Kijowska, A., & Mierzejewska, B. (2015). Combining digital speckle pattern interferometry with shearography in a new instrument to characterize surface delamination in museum artefacts. Journal of Cultural Heritage, 16(4), 544-550. doi:10.1016/j.culher.2014.10.006Trumpy, G., Conover, D., Simonot, L., Thoury, M., Picollo, M., & Delaney, J. K. (2015). Experimental study on merits of virtual cleaning of paintings with aged varnish. Optics Express, 23(26), 33836. doi:10.1364/oe.23.033836Reifsnyder, J. M. (1996). A note on a traditional technique of varnish application for paintings on panel. Studies in Conservation, 41(2), 120-122. doi:10.1179/sic.1996.41.2.120Caley, T. (1990). ASPECTS OF VARNISHES AND THE CLEANING OF OIL PAINTINGS BEFORE 1700. Studies in Conservation, 35(sup1), 70-72. doi:10.1179/sic.1990.35.s1.016Bruckle, I., Thornton, J., Nichols, K., & Strickler, G. (1999). Cyclododecane: Technical Note on Some Uses in Paper and Objects Conservation. Journal of the American Institute for Conservation, 38(2), 162. doi:10.2307/3180044Rowe, S., & Rozeik, C. (2008). The uses of cyclododecane in conservation. Studies in Conservation, 53(sup2), 17-31. doi:10.1179/sic.2008.53.supplement-2.17Maish, J. P., & Risser, E. (2002). A Case Study in the Use of Cyclododecane and Latex Rubber in the Molding of Marble. Journal of the American Institute for Conservation, 41(2), 127. doi:10.2307/3179789Lenk, R. S., Fellers, J. F., & White, J. L. (1977). Comparative Study of Polyamides from Bisacid A2. Polymer Journal, 9(1), 9-17. doi:10.1295/polymj.9.9Carvalho, P. H. A., Barreto, J. B., Braga, R. A., & Rabelo, G. F. (2009). Motility parameters assessment of bovine frozen semen by biospeckle laser (BSL) system. Biosystems Engineering, 102(1), 31-35. doi:10.1016/j.biosystemseng.2008.09.025Richards, L. M., Kazmi, S. M. S., Davis, J. L., Olin, K. E., & Dunn, A. K. (2013). Low-cost laser speckle contrast imaging of blood flow using a webcam. Biomedical Optics Express, 4(10), 2269. doi:10.1364/boe.4.002269Ganilova, Y. A., & Ulyanov, S. S. (2006). A study of blood flow in microvessels using biospeckle dynamics. Biophysics, 51(2), 299-304. doi:10.1134/s0006350906020230Murialdo, S. E., Sendra, G. H., Passoni, L. I., Arizaga, R., Gonzalez, J. F., Rabal, H., & Trivi, M. (2009). Analysis of bacterial chemotactic response using dynamic laser speckle. Journal of Biomedical Optics, 14(6), 064015. doi:10.1117/1.3262608González-Peña, R. J., Braga, R. A., Cibrián, R. M., Salvador-Palmer, R., Gil-Benso, R., & Miguel, T. S. (2014). Monitoring of the action of drugs in melanoma cells by dynamic laser speckle. Journal of Biomedical Optics, 19(5), 057008. doi:10.1117/1.jbo.19.5.057008Arizaga, R., Grumel, E. E., Cap, N., Trivi, M., Amalvy, J. I., Yepes, B., & Ricaurte, G. (2006). Following the drying of spray paints using space and time contrast of dynamic speckle. Journal of Coatings Technology and Research, 3(4), 295-299. doi:10.1007/s11998-006-0025-2Faccia, P. A., Pardini, O. R., Amalvy, J. I., Cap, N., Grumel, E. E., Arizaga, R., & Trivi, M. (2009). Differentiation of the drying time of paints by dynamic speckle interferometry. Progress in Organic Coatings, 64(4), 350-355. doi:10.1016/j.porgcoat.2008.07.016Mavilio, A., Fernández, M., Trivi, M., Rabal, H., & Arizaga, R. (2010). Characterization of a paint drying process through granulometric analysis of speckle dynamic patterns. Signal Processing, 90(5), 1623-1630. doi:10.1016/j.sigpro.2009.11.010Budini, N., Mulone, C., Balducci, N., Vincitorio, F. M., López, A. J., & Ramil, A. (2016). Characterization of drying paint coatings by dynamic speckle and holographic interferometry measurements. Applied Optics, 55(17), 4706. doi:10.1364/ao.55.004706Brunel, L., Brun, A., & Snabre, P. (2006). Microstructure movements study by dynamic speckle analysis. Speckle06: Speckles, From Grains to Flowers. doi:10.1117/12.695493Braga, R. A., & González-Peña, R. J. (2016). Accuracy in dynamic laser speckle: optimum size of speckles for temporal and frequency analyses. Optical Engineering, 55(12), 121702. doi:10.1117/1.oe.55.12.121702Moreira, J., Cardoso, R. R., & Braga, R. A. (2014). Quality test protocol to dynamic laser speckle analysis. Optics and Lasers in Engineering, 61, 8-13. doi:10.1016/j.optlaseng.2014.04.005Ansari, M. Z., & Nirala, A. K. (2016). Biospeckle numerical assessment followed by speckle quality tests. Optik, 127(15), 5825-5833. doi:10.1016/j.ijleo.2016.04.010Oulamara, A., Tribillon, G., & Duvernoy, J. (1989). Biological Activity Measurement on Botanical Specimen Surfaces Using a Temporal Decorrelation Effect of Laser Speckle. Journal of Modern Optics, 36(2), 165-179. doi:10.1080/09500348914550221Braga, R. A., Nobre, C. M. B., Costa, A. G., Sáfadi, T., & da Costa, F. M. (2011). Evaluation of activity through dynamic laser speckle using the absolute value of the differences. Optics Communications, 284(2), 646-650. doi:10.1016/j.optcom.2010.09.064Narita, T., Beauvais, C., Hébraud, P., & Lequeux, F. (2004). Dynamics of concentrated colloidal suspensions during drying --aging, rejuvenation and overaging. The European Physical Journal E, 14(3), 287-292. doi:10.1140/epje/i2004-10018-0Puspasari, I., Talib, M. Z. M., Daud, W. R. W., & Tasirin, S. M. (2014). Characteristic Drying Curve of Oil Palm Fibers. International Journal on Advanced Science, Engineering and Information Technology, 4(1), 20. doi:10.18517/ijaseit.4.1.361Bellagha, S., Amami, E., Farhat, A., & Kechaou, N. (2002). DRYING KINETICS AND CHARACTERISTIC DRYING CURVE OF LIGHTLY SALTED SARDINE (SARDINELLA AURITA). Drying Technology, 20(7), 1527-1538. doi:10.1081/drt-120005866Van der Kooij, H. M., Fokkink, R., van der Gucht, J., & Sprakel, J. (2016). Quantitative imaging of heterogeneous dynamics in drying and aging paints. Scientific Reports, 6(1). doi:10.1038/srep34383Vaz, P., Pereira, T., Figueiras, E., Correia, C., Humeau-Heurtier, A., & Cardoso, J. (2016). Which wavelength is the best for arterial pulse waveform extraction using laser speckle imaging? Biomedical Signal Processing and Control, 25, 188-195. doi:10.1016/j.bspc.2015.11.01