La geometría de visualización afecta el dicromatismo sexual y la conspicuidad de la coloración del plumaje no iridiscente de Tersina viridis

Some types of plumage color are difficult to characterize spectrophotometrically because the properties of the reflected light change with viewing geometry (i.e. the relative positions of the light source and the observer, and the orientation of the feather). This is the case for the noniridescent plumage coloration of the Swallow Tanager (Tersina viridis), which seems to change from a human perspective as the angle between the light source and the observer varies. In this study, we measured plumage reflectance with different angles of illumination and/or observation, and used avian visual models to evaluate the change in sexual dichromatism and conspicuousness with viewing geometry from a bird’s perspective. We also calculated different color parameters to assess how these changed with viewing conditions. Sexual dichromatism showed large changes, with its maximum coinciding with the angle combination between illuminant and observer that produced both the highest conspicuousness for males and the highest crypsis for females. The conspicuousness of males also varied with viewing geometry, and was consistently less when viewed by the visual system of a potential avian predator (VS) than by that of a conspecific (UVS). The change in perceived coloration was mainly related to large variation in hue and chroma in the plumage of males as the relative angle between the illumination and observation probes changed. Our results show that viewing geometry can alter color perception, even for noniridescent plumage coloration. Therefore, the relative position of the light source and the observer should be considered in studies of avian visual communication, particularly for species with plumage coloration similar to that of Swallow Tanagers.Algunos tipos de colores del plumaje son difíciles de caracterizar espectrofotometricamente debido a que las propiedades de la luz que reflejada varían con la geometría de visualización (es decir, la posición relativa de la fuente lumínica, el observador y la pluma). Este es el caso de la coloración no-iridiscente de la Tersina viridis, que parece cambiar desde la perspectiva humana al modificarse el ángulo conformado entre el observador y la fuente de luz. En este trabajo medimos la reflectancia del plumaje con diferentes ángulos de iluminación y/o observación y empleamos modelos visuales avianos para evaluar el cambio en dicromatismo sexual y conspicuidad. Tambien calculamos parámetros descriptores de la coloración para determinar cómo cambian estos en función de la geometría de visualización. El dicromatismo sexual mostró una amplia variación, siendo máximo con la combinación de ángulos entre iluminante y observador que también produjo el máximo de conspicuidad en los machos y el máximo de cripsis en las hembras. La conspicuidad de los machos tambien varió con la geometría de visualización y además fue consistentemente menor para sistemas visuales avianos menos sensibles al UV (como los de los máximos potenciales predadores de esta especie) que para sus conspecíficos, que serían más sensibles a longitudes de onda del UV. El cambio percibido en la coloración estuvo principalmente relacionado a una gran variación en el tono y la saturación en el plumaje de los machos al cambiar el ángulo conformado entre la fuente lumínica y el observador. Nuestros resultados muestran que la geometría de visualización puede alterar la percepción del color, a un en plumajes no-iridiscentes. Por lo tanto, es importante considerar la posición relativa de la fuente de luz y el observador en estudios de comunicación visual en aves, particularmente en especies con coloración del plumaje como la de la Tersina viridis.Fil: Barreira, Ana Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: García, Natalia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lougheed, Stephen C.. Queens University, Department Of Biology; CanadáFil: Tubaro, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Hydroalkoxylation of Terminal and Internal Alkynes Catalyzed by Dinuclear Gold(I) Complexes with Bridging Di(N-Heterocyclic Carbene) Ligands

A series of six dinuclear gold(I) complexes with bridging bidentate N-heterocycic carbene ligands (NHCs) of general formula Au2Br2LX (L = diNHC, X = 1\u20136) have been studied as catalysts in the intermolecular hydroalkoxylation of terminal and internal alkynes. The best catalytic results have been obtained by using Au2Br2L4, characterized by 2,6-diisopropylphenyl wingtip substituents and a methylene bridging group between the two NHC donors. Complex Au2Br2L4 has been structurally characterized for the first time in this work, showing the presence of intramolecular aurophiclic interaction in the solid state. In the adopted reaction conditions Au2Br2L4 is able to convert challenging substrates such as diphenylacetylene. Comparative catalytic tests by using the mononuclear gold(I) complexes AuIL7 and IPrAuCl have been performed in order to determine the possible presence of cooperative effects in the catalytic process

Assessment of skin sensitization properties of few-layer graphene and graphene oxide through the Local Lymph Node Assay (OECD TG 442B)

: Skin contact is one of the most common exposure routes to graphene-based materials (GBMs) during their small-scale and industrial production or their use in technological applications. Nevertheless, toxic effects in humans by cutaneous exposure to GBMs remain largely unexplored, despite skin contact to other related materials has been associated with adverse effects. Hence, this in vivo study was carried out to evaluate the cutaneous effects of two GBMs, focusing on skin sensitization as a possible adverse outcome. Skin sensitization by few-layer graphene (FLG) and graphene oxide (GO) was evaluated following the Organization for Economic Cooperation and Development (OECD) guideline 442B (Local Lymph Node Assay; LLNA) measuring the proliferation of auricular lymph node cells during the induction phase of skin sensitization. Groups of four female CBA/JN mice (8-12 weeks) were daily exposed to FLG or GO through the dorsal skin of each ear (0.4-40 mg/mL, equal to 0.01-1.00 mg/ear) for 3 consecutive days, and proliferation of auricular lymph node cells was evaluated 3 days after the last treatment. During this period, no clinical signs of toxicity and no alterations in body weight and food or water consumptions were observed. In addition, no ear erythema or edema were recorded as signs of irritation or inflammation. Bromo-deoxyuridine (BrdU) incorporation in proliferating lymphocytes from ear lymph nodes (stimulation indexes <1.6) and the histological analysis of ear tissues excluded sensitizing or irritant properties of these materials, while myeloperoxidase activity in ear biopsies confirmed no inflammatory cells infiltrate. On the whole, this study indicates the absence of sensitization and irritant potential of FLG and GO

Cobalt Spinel Nanocubes on N-Doped Graphene: A Synergistic Hybrid Electrocatalyst for the Highly Selective Reduction of Carbon Dioxide to Formic Acid

Carbon dioxide reduction into useful chemical products is a key technology to address urgent climate and energy challenges. In this study, a nanohybrid made by Co₃O₄ and graphene is proposed as an efficient electrocatalyst for the selective reduction of CO₂ to formate at low overpotential. A comparison between samples with different metal oxide to carbon ratios and with or without doping of the graphene moiety indicates that the most active catalyst is formed by highly dispersed and crystalline nanocubes exposing {001} oriented surfaces, whereas the nitrogen doping is critical to obtain a controlled morphology and to facilitate a topotactic transformation during electrocatalytic conditions to CoO, which results in the true active phase. The nanohybrid made up by intermediate loading of Co₃O₄ supported on nitrogen-doped graphene is the most active catalyst, being able to produce 3.14 mmol of formate in 8 h at −0.95 V vs SCE with a Faradaic efficiency of 83%

Skin irritation potential of graphene-based materials using a non-animal test

Graphene related materials, if prepared with non-irritant exfoliation agents, do not induce skin irritation on a 3D model of human epidermis, following the OECD guideline 439

Psychiatric Disorders and Oxidative Injury: Antioxidant Effects of Zolpidem Therapy disclosed In Silico

Zolpidem (N,N-Dimethyl-2-[6-methyl-2-(4-methylphenyl)imidazo[1,2-a]pyridin-3-yl]acetamide) is a well-known drug for the treatment of sleeping disorders. Recent literature reports on positive effects of zolpidem therapy on improving renal damage after cisplatin and on reducing akinesia without sleep induction. This has been ascribed to the antioxidant and neuroprotective capacity of this molecule, and tentatively explained according to a generic structural similarity between zolpidem and melatonin. In this work, we investigate in silico the antioxidant potential of zolpidem as scavenger of five ROSs, acting via hydrogen atom transfer (HAT) mechanism; computational methodologies based on density functional theory are employed. For completeness, the analysis is extended to six metabolites. Thermodynamic and kinetic results disclose that indeed zolpidem is an efficient radical scavenger, similarly to melatonin and Trolox, supporting the biomedical evidence that the antioxidant potential of zolpidem therapy may have a beneficial effect against oxidative injury, which is emerging as an important etiopathogenesis in numerous severe diseases, including psychiatric disorders

Keratinocytes are capable of selectively sensing low amounts of graphene-based materials: Implications for cutaneous applications

Abstract Skin provides the first interface between body and environment, representing one of the most feasible exposure routes to graphene-based materials (GBMs). However, interactions of GBMs with the skin are poorly understood. In particular, low-concentration effects have not been investigated. Here we explored the ability of endotoxin-free, few-layer graphene (FLG) and dehydrated graphene oxide (d-GO) to initiate an inflammatory response at the cutaneous level by using human HaCaT keratinocytes. HaCaT cell exposure to low concentrations (0.01–1.0 μg/mL) of FLG or d-GO did not affect cell viability. FLG triggered the secretion of pro-inflammatory tumor necrosis factor-α (TNF-α), interleukin (IL)-1α, and IL-6, while d-GO, and to a lesser extent FLG, prompted IL-8 (CXCL8) production. However, conditioned medium from HaCaT cells exposed to FLG or d-GO had no effect on THP-1 monocyte activation. Moreover, co-culture experiments did not show any effect of FLG- or d-GO-treated HaCaT cells on THP-1 cell migration. These results suggest that while GBMs are able to initiate an inflammatory response in keratinocytes, this does not necessarily lead to activation of monocytes. The present findings are relevant for potential dermal exposures to GBMs in occupational settings as well as the use of GBMs for cutaneous applications such as in wearable sensors

Hazard characterization of graphene-based nanomaterials in energy production and storage (GrapHazard)

This publication is the final report of the research project “Hazard characterization of graphene-based nanomaterials in energy production and storage (GrapHazard)”, funded by the Finnish Work Environmental Fund, the Italian National Institute for Insurance against Accidents at Work (INAIL), the Finnish Institute of Occupational Health, and the University of Trieste in the frame of the SAF€RA 2020 program. The report summarizes the findings of the toxicological assessment of different types of graphene-based materials by using an in vitro lung system to investigate the involved mechanisms of action and how different key physicochemical properties of the materials can modulate the toxic response. In addition, recommendations for a safe use of graphene-based materials in occupational settings are provided

Laparoscopic simple prostatectomy vs bipolar plasma enucleation of the prostate in large benign prostatic hyperplasia. a two-center 3-year comparison

Purpose: To compare surgery outcomes and safety of button bipolar enucleation of the prostate vs laparoscopic simple prostatectomy in patients with large prostates (&gt; 80&nbsp;g) in a two-center cohort study. Methods: All patients with lower urinary tract symptoms due to benign prostatic enlargement (Prostate volume &gt; 80&nbsp;cc) undergoing button bipolar enucleation of the prostate (BTUEP) or laparoscopic simple prostatectomy (LSP) in two centers were enrolled. Data on clinical history, physical examination, urinary symptoms, uroflowmetry and prostate volume were collected at 0, 1, 3 6, 12, 24 and 36&nbsp;months. Early and long-term complications were recorded. Results: Overall, 296 patients were enrolled. Out of them, 167/296 (56%) performed a LSP and 129/296 (44%) performed a BTUEP. In terms of efficacy both procedures showed durable results at three years with a reintervention rate of 8% in the LSP group and of 5% in the BTUEP group. In terms of safety, BTUEP and LSP presented similar safety profiles with a 9% of transfusion rate and no major complications. Conclusion: LSP and BTUEP are safe and effective in treating large-volume adenomas with durable results at three years when performed in experienced centers

Graphene and graphene oxide induce ROS production in human HaCaT skin keratinocytes: The role of xanthine oxidase and NADH dehydrogenase

The extraordinary physicochemical properties of graphene-based nanomaterials (GBNs) make them promising tools in nanotechnology and biomedicine. Considering the skin contact as one of the most feasible exposure routes to GBNs, the mechanism of toxicity of two GBNs (few-layer-graphene, FLG, and graphene oxide, GO) towards human HaCaT skin keratinocytes was investigated. Both materials induced a significant mitochondrial membrane depolarization: 72 h cell exposure to 100 \u3bcg mL 12 1 FLG or GO increased mitochondrial depolarization by 44% and 56%, respectively, while the positive control valinomycin (0.1 \u3bcg mL 121) increased mitochondrial depolarization by 48%. Since the effect was not prevented by cyclosporine-A, it appears to be unrelated to mitochondrial transition pore opening. By contrast, it seems to be mediated by reactive oxygen species (ROS) production: FLG and GO induced time- and concentration- dependent cellular ROS production, significant already at the concentration of 0.4 \u3bcg mL 121 after 24 h exposure. Among a panel of specific inhibitors of the major ROS-producing enzymes, diphenyliodonium, rotenone and allopurinol significantly reverted or even abolished FLG- or GO-induced ROS production. Intriguingly, the same inhibitors also significantly reduced FLG- or GO-induced mitochondrial depolarization and cytotoxicity. This study shows that FLG and GO induce a cytotoxic effect due to a sustained mitochondrial depolarization. This seems to be mediated by a significant cellular ROS production, caused by the activation of flavoprotein-based oxidative enzymes, such as NADH dehydrogenase and xanthine oxidase