Photogenerated Electrical Fields for Biomedical Applications

The application of electrical engineering principles to biology represents the main issue of bioelectronics, focusing on interfacing of electronics with biological systems. In particular, it includes many applications that take advantage of the peculiar optoelectronic and mechanical properties of organic or inorganic semiconductors, from sensing of biomolecules to functional substrates for cellular growth. Among these, technologies for interacting with bioelectrical signals in living systems exploiting the electrical field of biomedical devices have attracted considerable attention. In this review, we present an overview of principal applications of phototransduction for the stimulation of electrogenic and non-electrogenic cells focusing on photovoltaic-based platforms

Echinoderms from the Museum of Zoology from the Universidad de Costa Rica

El Museo de Zoología de la Universidad de Costa Rica (MZUCR) se funda en 1966 y alberga la colección de organismos vertebrados e invertebrados más completa de Costa Rica. El MZUCR cuenta actualmente con 24 colec-ciones que contienen más de cinco millones de especíme-nes, y más de 13 000 especies identificadas. Las primeras colecciones datan 1960 e incluyen peces, reptiles, anfibios, poliquetos, crustáceos y equinodermos. Para este último grupo, el MZUCR posee un total de 157 especies, en 1 173 lotes y 4 316 ejemplares. Estas 157 especies representan el 54% del total de especies de equinodermos que posee Costa Rica (293 especies). El resto de especies están repar-tidas en las siguientes instituciones: Academia de la Cien-cias de California (CAS) (4.8%), Instituto Oceanográfico Scripps (SIO) (5.2%), en la Colección Nacional de equino-dermos “Dra. Ma. Elena Caso” de la Universidad Nacional Autónoma de México (ICML-UNAM) (12.7%), Museo de Zoología Comparada de Harvard (MZC) (19.2%), y en el Museo Nacional de Historia Natural del Instituto Smithso-niano (USNM) (35.1%). Es posible que haya material de Costa Rica en el Museo de Historia Natural de Dinamarca (NCD) y en el Museo de Historia Natural de los Ángeles (LACM), sin embargo, no hubo acceso a dichas coleccio-nes. A su vez hay 9.6% de especies que no aparecen en ningún museo, pero están reportadas en la literatura. Con base en esta revisión de colecciones se actualizó el listado taxonómico de equinodermos para Costa Rica que consta de 293 especies, 152 géneros, 75 familias, 30 órdenes y cinco clases. La costa Pacífica de Costa Rica posee 153 especies, seguida por la isla del Coco con 134 y la costa Caribe con 65. Holothuria resultó ser el género más rico con 25 especies.The Museum of Zoology, Universidad de Costa Rica (MZUCR) was founded in 1966 and houses the most complete collection of vertebrates and invertebrates in Costa Rica. The MZUCR currently has 24 collections containing more than five million specimens, and more than 13 000 species. The earliest collections date back to 1960 and include fishes, reptiles, amphibians, polychaetes, crustaceans and echinoderms. For the latter group, the MZUCR has a total of 157 species, in 1 173 lots and 4 316 specimens. These 157 species represent 54% of the total species of echino-derms from Costa Rica. The remaining species are distributed in the following institutions: California Academy of Sciences (CAS) (4.8%), Scripps Oceanographic Institute (SIO) (5.2%), National Echinoderm Collection “Dr. Ma. Elena Caso” from the National Autonomous University of Mexico (ICML-UNAM) (12.7%), the National Museum of Natural History, Smithsonian Institute (USNM) (35.1%), and the Harvard Museum of Comparative Zoology (19.2%). There may be material from Costa Rica in the Natural History Museum of Denmark (NCD) and the Natural History Museum of Los Angeles (LACM), however, there was no access to such collections. There are 9.6% that do not appear in museums, but are reported in the literature. Based on this revision, the taxonomic list of echinoderms for Costa Rica is updated to 293 species, 152 genera, 75 families, 30 orders and 5 classes. The Pacific coast of Costa Rica has 153 species, followed by the Isla del Coco with 134 and the Caribbean coast with 65. Holothuria is the most diverse genus with 25 species.UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de BiologíaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Artes y Letras::Museo de la Universidad de Costa Ric

Il trattamento chirurgico laparoscopico delle cisti idatidee epatiche: tecnica personale

Il trattamento delle cisti idatidee epatiche è ancor oggi ampiamente dibattuto. Alle modalità di trattamento tradizionali, quali le terapie mediche antiparassitarie, le procedure radiologiche e gli interventi chirurgici a cielo aperto, si è di recente affiancata la procedura laparoscopica. Molti aspetti riguardanti il trattamento laparoscopico delle cisti idatidee rimangono a tutt’oggi controversi. L’utilizzo dell’approccio mini-invasivo proposto in letteratura da alcuni autori è gravato da un’incidenza di recidive dallo 0 al 9%, in follow-up da 3 a 49 mesi. Inconvenienti della tecnica laparoscopica sono le difficoltà di controllo dello “spillage” e la disseminazione peritoneale, nonché l’incompleta aspirazione delle cisti a contenuto denso. Gli Autori hanno rivisto i dati della letteratura e descrivono una tecnica personale al fine di evitare gli inconvenienti descritti e di ridurre l’incidenza delle recidive postchirurgiche

Graphene with Ni-Grid as Semitransparent Electrode for Bulk Heterojunction Solar Cells (BHJ-SCs)

In this work, we present the fabrication and characterization of bulk-heterojunction solar cells on monolayer graphene (MLG) with nickel-grids (Ni-grid) as semitransparent conductive electrode. The electrodes showed a maximum transmittance of 90% (calculated in 300–800 nm range) and a sheet resistance down to 35 Ω/□. On these new anodes, we fabricated TCO free BHJ-SCs using PTB7 blended with PC70BM fullerene derivative as active layer. The best device exhibited a power conversion efficiency (PCE) of 4.2% in direct configuration and 3.6% in inverted configuration. The reference solar cell, realized on the ITO glass substrate, achieved a PCE of 6.1% and 6.7% in direct and inverted configuration respectively; for comparison we also tested OSCs only with simple Ni-grid as semitransparent and conductive electrode, obtaining a low PCE of 0.7%. The proposed approach to realize graphene-based electrodes could be a possible route to reduce the overall impact of the sheet resistance of this type of electrodes allowing their use in several optoelectronic devices

ITO based fully‐spray coated inverted solar cells with non‐toxic solvents: The role of buffer layers interface on low band gap photoactive layer performance

In bulk heterojunction solar cells, the morphology of the interfaces between photoactive layer and transporting/collecting electrodes during the deposition process play a key role for achieving high efficiency devices. In this work, we present a fully spray coated solar cell realized in inverted architecture on ITO glass substrate and the influence of spray coated transporting layer is evaluated. In particular, we report the realization of a spray coated double electron transporting layer (ETL) using zinc oxide nanoparticles coated with polyethylenimine ethoxylated (PEIE) which allows improving the morphology of the spray coated active layer on top of the spray coated cathode. The approach used in our experiments to realize the hole transporting layer (HTL) and the anode was firstly, a sprayble solution prepared using a blend of two commercial poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). We compared the devices realized using PEDOT:PSS blend with devices prepared using a high conductive anhydrous PEDOT:PSS (A-PEDOT) formulation developed in our laboratory. Optimizing the spray deposition of all the organic layers, we demonstrated the possibility to realize a fully spray scalable process to realize polymer solar cells on ITO with the structure ITO/ZnO/PEIE/PTB7:PCBM/CPP:A-PEDOT that reached a power conversion efficiency of 3.6%. This value was a great result with respect to not fully scalable processes based on spray coated structure with evaporated anode (MoO3-Ag), making. In this case (ITO/ZnO/PEIE/PTB7:PCBM/MoO3Ag) a power conversion efficiency of 5.5% was achieved

Scaling-Up of Solution-Processable Tungsten Trioxide (WO₃) Nanoparticles as a Hole Transport Layer in Inverted Organic Photovoltaics

We reported the comparative studies of the optimization of solution-processable tungsten trioxide (WO3) as a hole transporting layer (HTL) in inverted organic photovoltaics (OPVs) using spin coating, slot-die coating, and spray coating technologies for scaling-up applications. To facilitate the technology’s transition into commercial manufacturing, it is necessary to explore the role of scalable technologies for low-cost and efficient device fabrication. We investigated the role of diluting WO3 with isopropanol as an HTL in inverted OPVs to solve the issue of poor wettability of the hydrophobic surface of the PBDB-T: ITIC bulk heterojunction layer. The optimal dilution ratios of WO3 with isopropanol were 1:4, 1:4 and 1:8 with spin coating, slot-die coating and spray coating techniques, respectively. We evaluated the device performance by conducting a current density–voltage (J-V) analysis, incident photon-to-current conversion efficiency (IPCE) measurements, and ultraviolet–visible (UV-Vis) absorbance spectra for various WO3 concentrations. The J-V characteristics revealed that slot-die coating resulted in the highest performance, followed by the spray coating technology. We further investigated the impact of the annealing temperature on device performance for both slot-die- and spray-coated diluted WO3. The highest device performance was achieved at an annealing temperature of 120 °C for both coating technologies. This research offers valuable insights into the scalable fabrication of inverted OPV devices, paving the way for cost-effective and efficient large-scale production

Photonic Flash Sintering of Ink-Jet-Printed Back Electrodes for Organic Photovoltaic Applications

A study of the photonic flash sintering of a silver nanoparticle ink printed as the back electrode for organic solar cells is presented. A number of sintering settings with different intensities and pulse durations have been tested on both full-area and grid-based silver electrodes, using the complete emission spectrum of the flash lamps from UV-A to NIR. However, none of these settings was able to produce functional devices with performances comparable to those of reference cells prepared using thermally sintered ink. Different degradation mechanisms were detected in the devices with a flash-sintered back electrode. The P3HT:PCBM photoactive layer appears to be highly heat-sensitive and turned out to be severely damaged by the high temperatures generated in the silver layer during the sintering. In addition, UV-induced photochemical degradation of the functional materials was identified as another possible source of performance deterioration in the devices with grid-based electrodes. Reducing the light intensity does not provide a proper solution because in this case the Ag electrode is not sintered sufficiently. For both types of devices, with full-area and grid-based electrodes, these problems could be solved by excluding the short wavelength contribution from the flash light spectrum using a filter. Optimized sintering parameters allowed manufacture of OPV devices with performance equal to those of the reference devices. Photonic flash sintering of the top electrode in organic solar cells was demonstrated for the first time. It reveals the great potential of this sintering method for the future roll-to-roll manufacturing of organic solar cells from solution

On the role of PTB7-Th:[70]PCBM blend concentration in ortho-xylene on polymer solar cells performance

Low-band gap polymers as donors are the new approach to realize high efficiency polymer solar cells. Among them, PTB7-Th is one of the most promising candidates, thanks to the possibility of exploiting deposition protocols (technique, solvent, concentration) from the most-known PTB7, and demonstrating a power conversion efficiency exceeding 10%. In this paper, we focus on the role of the ink concentration for the film deposition and formation of the active layer. The effect of the solid content (PTB7-Th:[70]PCBM) in an ortho-xylene based solution on the polymer solar cell performance are investigated. Farther, a correlation between solid content and DIO additive in the ink formulation with respect to device performance is discussed. A remarkable PCE of 8.2% has been demonstrated