Geometry-induced enhancement factor improvement in covered-gold-nanorod-dimer antennas

Illuminated gapped-gold-nanorod dimers hold surface plasmon polaritons (SPPs) that can be engineered, by an appropriate choice of geometrical parameters, to enhance the electromagnetic field at the gap, allowing applications in molecular detection via surface-enhanced Raman spectroscopy (SERS). Envisioning hybrid devices in which the SERS spectroscopy of molecules in the gap is complemented by electrical measurements, it arises the question of designing efficient geometries to contact the nanorods without decreasing the enhancement factor (EF) of the nanoantenna, i.e., the figure of merit for SERS spectroscopy. Within this framework we theoretically study the feasibility to fabricate designs based on covering with gold the far-from-the-gap areas of the dimer. We show that by tuning the geometrical parameters of the designs these systems can reach enhancement factors larger than the best achieved in the uncovered dimer: this supremacy survives even in the presence of dimer asymmetries and vacancies at the interfaces between the nanorods and the covering layers. Our results show that geometrical modifications away from the gap can improve the optical response at the gap, thus enabling the use of these devices both for hybrid and optical applications.Comment: 10 pages, 8 figure

Effect of the excitation setup in the improved enhancement factor of covered-gold-nanorod-dimer antennas

Devices possessing the ability to sense both electrically and optically molecular targets are of fundamental and technological interest. Towards this end, it has been shown that covering the ends of gapped gold-nanorod-dimer nanoantennas can improve the enhancement factor (EF) that quantifies the nanoantenna efficiency for surface-enhancement Raman spectroscopy (SERS) for an incident wave coming from the top of the sample. Here, as the covering breaks the top-bottom symmetry, we investigate the behaviour of the EF for excitation coming from the bottom of the sample. This is relevant in presence of a reflecting substrate or due to the placement of the device in a cavity field. We also study the case of a superposition of waves coming from both directions in the limit cases in which a node or an antinode of the total incident field lies at the center of the gold nanorods. In all these situations we find that the EF of the covered device can continue to be higher than for the uncovered case when the geometrical parameters are tuned to the peak values of the calculated enhancement factor

Actividad repelente del aceite esencial de Laurelia sempervirens (Ruiz & Pav.) Tul. (Monimiaceae) en Triatoma infestans (Klug) (Reduviidae)

Triatoma infestans (Klug) is the principal vector of Chagas disease in Bolivia and neighboring countries. The objective of this study was to determine the chemical composition of the EO of the Chilean laurel, Laurelia sempervirens (Ruiz & Pav.) Tul. (Monimiaceae) and to evaluate its repellent effect on fifth-instar nymphs of T. infestans. The EO from L. sempervirens was obtained by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). Their main components were cis-isosafrole (89.8%), β-terpinene (3.9%), trans-ocimene (2.7%) and methyleugenol (2.2%). Repellency was evaluated on a circle of filter paper divided into two equal zones which were impregnated with test substances [EO or N,N-diethyl-3-methylbenzamide (DEET) as positive control] and acetone as blank control, respectively. Several concentrations of test substances between 4.125 and 132 μg/cm2 were tested. The EO from L. sempervirens produced significant repellency at concentrations equal or above 66.0 μg/cm2, while DEET repelled starting at 16.5 μg/cm2. Future works will be oriented to the study of repellent properties of cis-isosafrole alone and mixed with β-terpinene, trans-ocimene and methyleugenol on T. infestans.Triatoma infestans (Klug) es el vector principal de la enfermedad de Chagas en Bolivia y los países vecinos. El objetivo de este estudio fue determinar la composición química del AE del laurel chileno, Laurelia sempervirens (Ruiz & Pav.) Tul. (Monimiaceae) y evaluar su efecto repelente en ninfas del quinto estadio de T. infestans. La AE de L. sempervirens se obtuvo por hidrodestilación y se analizó por cromatografía de gases acoplada a espectrometría de masas (CG-EM). Sus componentes principales fueron cis-isosafrol (89.8%), βterpineno (3.9%), trans-ocimeno (2.7%) y metileugenol (2.2%). La repelencia se evaluó en un círculo de papel de filtro dividido en dos zonas iguales que se impregnaron con sustancias de prueba [AE o N,N-dietil-3-metilbenzamida (DEET) como control positivo] y acetona como control en blanco, respectivamente. Se analizaron varias concentraciones de sustancias de prueba entre 4.125 y 132 μg/cm2. El AE de L. sempervirens produjo una repelencia significativa a concentraciones iguales o superiores a 66.0 μg/cm2, mientras que DEET repelió a partir de 16.5 μg/cm2. Futuros trabajos serán orientados al estudio de las propiedades repelentes de cis-isosafrol solo y mezclado con βterpineno, trans-ocimeno y metileugenol en T. infestans.Fil: Mojica, Marycruz. Universidad Mayor Real y Pontificia de San Francisco Xavier de Chuquisaca; BoliviaFil: Alzogaray, Raúl Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; ArgentinaFil: Mengoni, Sofia Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; ArgentinaFil: Reynoso, Mercedes María Noel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; ArgentinaFil: Pinto, Carlos Fernando. Universidad Mayor Real y Pontificia de San Francisco Xavier de Chuquisaca; BoliviaFil: Niemeyer, Hermann M.. Universidad de Chile; ChileFil: Echeverría, Javier. Universidad de Santiago de Chile; Chil

Proximal chemical analysis and secondary metabolites in Washingtonia robusta fruit (Arecaceae): relevance for the feeding of wildlife and human

Background: Washingtonia robusta fruits are a staple for birds, small and medium-size mammals, and humans. However, quantitative data of their nutritional contribution has remained unknown. This is the first report on the phytochemical components found in fruit pulp and seeds. Questions: Does pulp compounds favor its consumption and contribute with nutrients for wildlife and humans? Do seed contents favor ecological interactions for germination and plantlet development? Species study: Washingtonia robusta H. Wendl. Study site and dates: Sierra El Aguaje, Sonora, Mexico, February - April 2016 Methods: Chemical and secondary metabolite analyses were carried out from extracts via phytochemical coloring tests and ultra-resolution liquid chromatography. Antioxidant activity was analyzed by DPPH. Results: Washingtonia robusta seeds contain 73 % sugars, 7.4 % protein, 8.4 % humidity, 4.3 % ashes, 8.7 % fat and 0.2 % calcium, while cyanogenic glycosides content was 0.8 mu g/g. Pulp has 71 % sugars, 10.8 % protein, 1.6 % humidity, 5.5 % ashes, 9.4 % fat and 1.5 % calcium, and cyanogenic glycosides reached 0.2 mu g/g. Alkaloids, tannins, saponins, phenols, and flavonoids were more abundant in seeds than in pulp. The DPPH assay expressed in Trolox equivalents indicated antioxidant capacity. Conclusions: Washingtonia robusta pulp is an important source of sugars and natural antioxidants for wildlife and human consumption. Occurrence of secondary metabolites prevents pathogens in seeds, also they could be beneficial for germination and initial plantlet development.Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Modos de crecimiento y organización institucional. El caso de la Facultad de Ciencias de la Educación de la UNER

Esta reseña da cuenta de una investigación evaluativa que se propuso describir y explicar las formas de crecimiento de la Facultad de Ciencias de la Educación a través de la organización de algunos espacios institucionales y comprender cómo es percibida la institución por algunos actores vinculados a ella desde sus respectivos lugares de inserción institucional. Motivó esta investigación la advertencia de tensiones en el funcionamiento de la organización institucional que podrían explicarse por la amplitud y variedad de propuestas e intervenciones académicas, administrativas y presupuestarias en tanto formas que toma el crecimiento institucional. Para el abordaje metodológico se trabajó desde una perspectiva cualitativa e interpretativa, desde la cual se tomó a la Facultad de Ciencias de la Educación de la uner como caso. Para ello, se analizaron documentos y se realizaron entrevistas a informantes en función de su rol en los respectivos espacios institucionales. Cabe mencionar que el equipo de esta investigación evaluativa se conformó, principalmente, por los responsables de la gestión 2010-2014 de la Facultad. Se considera que los resultados de esta investigación podrán contribuir a la reflexión sobre cuestiones de gobierno en una institución que no se rige por una forma de planeamiento centralizado y a la ulterior toma de decisiones

Pathogenic vibrios in the oyster Crassostrea virginica in the lagoon system of Mandinga, Veracruz, Mexico

Oyster consumption has been associated to the transmission of pathogenic bacteria, including those from the genus Vibrio. The objective of this investigation was to determine the concentrations of Vibrio parahaemolyticus and V. alginolyticus in Crassostrea virginica from the lagoon system of Mandinga, Veracruz, and their relationships with salinity and water temperature. Only the periods of greater production and consumption of oysters were examined: the dry and rainy seasons during 2008. Four sampling sites were selected, from which three samples were collected per site per season, resulting in a total of 24 samples. Each sample consisted of 30 oysters of commercial size that were subsequently analyzed using serial dilution. Biochemical analysis of the resulting bacterial colonies revealed concentrations of V. parahaemolyticus and V. alginolyticus ranged from < 3 to 150 MPN/g. A positive correlation was observed between temperature and the concentration of V. parahaemolyticus (r = 0.69, p < 0.05), while the correlation with salinity was negative (r = -0.68, p < 0.05). No significant correlations between the concentration of V. alginolyticus and water temperature and salinity were observed for the rainy season. The main contribution of this paper is to establish safe areas and periods for oyster extraction

Antitumor activity against murine lymphoma L5178Y model of proteins from cacao (Theobroma cacao L.) seeds in relation with in vitro antioxidant activity

<p>Abstract</p> <p>Background</p> <p>Recently, proteins and peptides have become an added value to foodstuffs due to new knowledge about its structural analyses as related to antioxidant and anticancer activity. Our goal was to evaluate if protein fractions from cacao seeds show antitumor activity on lymphoma murine L5178Y model. The antioxidant activity of these fractions was also evaluated with the aim of finding a correlation with the antitumor activity.</p> <p>Methods</p> <p>Differential extraction of proteins from unfermented and semi-fermented-dry cacao seeds was performed and characterized by SDS-PAGE and FPLC size-exclusion chromatography. Antitumor activity was evaluated against murine lymphoma L5178Y in BALB/c mice (6 × 10⁴cells i.p.), with a treatment oral dose of 25 mg/kg/day of each protein fraction, over a period of 15 days. Antioxidant activity was evaluated by the ABTS⁺and ORAC-FL assays.</p> <p>Results</p> <p>Albumin, globulin and glutelin fractions from both cacao seed type were obtained by differential solubility extraction. Glutelins were the predominant fraction. In the albumin fraction, polypeptides of 42.3 and 8.5 kDa were found in native conditions, presumably in the form of two peptide chains of 21.5 kDa each one. The globulin fraction presented polypeptides of 86 and 57 kDa in unfermented cacao seed that produced the specific-cacao aroma precursors, and after fermentation the polypeptides were of 45 and 39 kDa. The glutelin fraction presented proteins >200 kDa and globulins components <100 KDa in lesser proportion. Regarding the semifermented-dry cacao seed, it was observed that the albumin fraction showed antitumoral activity, since it caused significant decreases (p < 0.05) in the ascetic fluid volume and packed cell volume, inhibiting cell growth in 59.98 ± 13.6% at 60% of the population; while the greatest antioxidant capacity due to free radical scavenging capacity was showed by the albumin and glutelin fraction in both methods assayed.</p> <p>Conclusion</p> <p>This study is the first report on the biological activity of semifermented-dry cacao protein fractions with their identification, supporting the traditional use of the plant. The albumin fraction showed antitumor and free radical scavenging capacity, however both activities were not correlated. The protein fractions could be considered as source of potential antitumor peptides.</p

Stress and worry in the 2020 coronavirus pandemic : relationships to trust and compliance with preventive measures across 48 countries in the COVIDiSTRESS global survey

The COVIDiSTRESS global survey collects data on early human responses to the 2020 COVID-19 pandemic from 173 429 respondents in 48 countries. The open science study was co-designed by an international consortium of researchers to investigate how psychological responses differ across countries and cultures, and how this has impacted behaviour, coping and trust in government efforts to slow the spread of the virus. Starting in March 2020, COVIDiSTRESS leveraged the convenience of unpaid online recruitment to generate public data. The objective of the present analysis is to understand relationships between psychological responses in the early months of global coronavirus restrictions and help understand how different government measures succeed or fail in changing public behaviour. There were variations between and within countries. Although Western Europeans registered as more concerned over COVID-19, more stressed, and having slightly more trust in the governments' efforts, there was no clear geographical pattern in compliance with behavioural measures. Detailed plots illustrating between-countries differences are provided. Using both traditional and Bayesian analyses, we found that individuals who worried about getting sick worked harder to protect themselves and others. However, concern about the coronavirus itself did not account for all of the variances in experienced stress during the early months of COVID-19 restrictions. More alarmingly, such stress was associated with less compliance. Further, those most concerned over the coronavirus trusted in government measures primarily where policies were strict. While concern over a disease is a source of mental distress, other factors including strictness of protective measures, social support and personal lockdown conditions must also be taken into consideration to fully appreciate the psychological impact of COVID-19 and to understand why some people fail to follow behavioural guidelines intended to protect themselves and others from infection. The Stage 1 manuscript associated with this submission received in-principle acceptance (IPA) on 18 May 2020. Following IPA, the accepted Stage 1 version of the manuscript was preregistered on the Open Science Framework at https://osf.io/g2t3b. This preregistration was performed prior to data analysis.Peer reviewe

COVIDiSTRESS Global Survey dataset on psychological and behavioural consequences of the COVID-19 outbreak

This N = 173,426 social science dataset was collected through the collaborative COVIDiSTRESS Global Survey - an open science effort to improve understanding of the human experiences of the 2020 COVID-19 pandemic between 30th March and 30th May, 2020. The dataset allows a cross-cultural study of psychological and behavioural responses to the Coronavirus pandemic and associated government measures like cancellation of public functions and stay at home orders implemented in many countries. The dataset contains demographic background variables as well as measures of Asian Disease Problem, perceived stress (PSS-10), availability of social provisions (SPS-10), trust in various authorities, trust in governmental measures to contain the virus (OECD trust), personality traits (BFF-15), information behaviours, agreement with the level of government intervention, and compliance with preventive measures, along with a rich pool of exploratory variables and written experiences. A global consortium from 39 countries and regions worked together to build and translate a survey with variables of shared interests, and recruited participants in 47 languages and dialects. Raw plus cleaned data and dynamic visualizations are available.Measurement(s) psychological measurement center dot anxiety-related behavior trait center dot Stress center dot response to center dot Isolation center dot loneliness measurement center dot Emotional Distress Technology Type(s) Survey Factor Type(s) geographic location center dot language center dot age of participant center dot responses to the Coronavirus pandemic Sample Characteristic - Organism Homo sapiens Sample Characteristic - Location global Machine-accessible metadata file describing the reported data:Peer reviewe

Impact of water potential on growth and germination of Fusarium solani soilborne pathogen of peanut

Studies were conducted to determine the effect of osmotic and matric stress on germination and growth of two Fusarium solani strains, the etiological agent responsible of peanut brown root rot. Both strains had similar osmotic and matric potential ranges that allowed growth, being the latter one narrower. F. solani showed the ability to grow down to -14 MPa at 25 °C in non-ionic modified osmotic medium, while under matric stress this was limited to -8.4 MPa at 25 °C. However, both strains were seen to respond differently to decreasing osmotic and matric potentials, during early stages of germination. One strain (RC 338) showed to be more sensitive to matric than osmotic (non ionic) and the other one (RC 386) showed to be more sensitive to osmotic than matric imposed water stress. After 24 h of incubation, both isolates behaved similarly. The minimum water potential for germination was -8.4 MPa on glycerol amended media and -5.6 MPa for NaCl and PEG amended media, respectively. The knowledge of the water potential range which allow mycelia growth and spore germination of F. solani provides an inside to the likely behaviour of this devastating soilborne plant pathogen in nature and has important practical implications