156 research outputs found

    Relación entre gestantes con anemia en edad materna de riesgo y bajo peso al nacer en un hospital de la seguridad social del Perú: Relationship between pregnant women with anemia at risk maternal age and low birth weight in a social security hospital in Peru

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    Objective: To determine the association between anemia in pregnant women with risk maternal age and low birth weight in the Obstetrics-Gynecology service of the Guillermo Almenara Irigoyen Hospital, in the period from October to December of the year 2018. Methods: A study of non-experimental, retrospective, cross-sectional, analytical, case-control type. In the period from October to December 2018, a total of 312 pregnant women with maternal age at risk (teenage and elderly pregnant women) were registered, of which 72 were anemic (Hb <11 g / dl), being the number of cases, and in order to improve statistical power, the relationship between cases and controls of 1: 2 was established, with the number of controls or non-anemic pregnant women with risk maternal age 142. The general characteristics are analyzed by group of anemic pregnant women and non-anemic, and its association with risk maternal age. The association of anemia in separately pregnant adolescents and elderly women with low birth weight is determined by Chi-square test and Odds ratio. Results: Among the variables studied anemic pregnant women, the highest frequency of nulliparity and vaginal delivery, and the lowest frequency of a history of abortion and adequate prenatal control. Teenage pregnant women with anemia were not associated with an increased risk of low birth weight (p = 0.056). Pregnant women who were anemic were associated with a 6-fold increased risk of low birth weight (95% CI: 2,219 to 18,026; p = 0.000). Conclusions: Elderly pregnant women have a higher risk of presenting products with low birth weight.Objetivo: Determinar la asociación entre anemia en gestantes con edad materna de riesgo y bajo peso al nacer. Métodos: Se realizó un estudio de tipo no experimental, retrospectivo, transversal, analítico, de casos y controles. En el periodo de octubre a diciembre del 2019, se registraron un total de 312 gestantes con edad materna de riesgo (gestantes adolescentes y añosas), de los cuales 72 eran anémicas (Hb < 11 g/dl), siendo este el número de casos, y con el fin de mejorar la potencia estadística se estableció la relación entre casos y controles de 1:2, siendo el número de controles o gestantes no anémicas con edad materna de riesgo 142. Se analizaron características generales por grupo de gestantes anémicas y no anémicas, y su asociación con edad materna de riesgo. Se determinó mediante prueba de Chi-cuadrado y Odds ratio la asociación de anemia en gestantes adolescentes y añosas por separado con bajo peso al nacer. Resultados: Entre las variables estudiadas las gestantes anémicas presentaron mayor frecuencia de nuliparidad y parto vaginal, y en menor frecuencia antecedente de aborto y control prenatal adecuado. Las gestantes adolescentes que cursaron con anemia no se asociaron a mayor riesgo de bajo peso al nacer (p=0.056). Las gestantes añosas que cursaron con anemia se asociaron a 6 veces mayor riesgo de bajo peso al nacer (IC:95%: 2,219 a 18,026; p=0,000). Conclusiones: Las gestantes añosas tienen mayor riesgo de presentar productos con bajo peso al nacer

    New method for analytical photovoltaic parameters identification: meeting manufacturer’s datasheet for different ambient conditions

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    At present, photovoltaic energy is one of the most important renewable energy sources. The demand for solar panels has been continuously growing, both in the industrial electric sector and in the private sector. In both cases the analysis of the solar panel efficiency is extremely important in order to maximize the energy production. In order to have a more efficient photovoltaic system, the most accurate understanding of this system is required. However, in most of the cases the only information available in this matter is reduced, the experimental testing of the photovoltaic device being out of consideration, normally for budget reasons. Several methods, normally based on an equivalent circuit model, have been developed to extract the I-V curve of a photovoltaic device from the small amount of data provided by the manufacturer. The aim of this paper is to present a fast, easy, and accurate analytical method, developed to calculate the equivalent circuit parameters of a solar panel from the only data that manufacturers usually provide. The calculated circuit accurately reproduces the solar panel behavior, that is, the I-V curve. This fact being extremely important for practical reasons such as selecting the best solar panel in the market for a particular purpose, or maximize the energy extraction with MPPT (Maximum Peak Power Tracking) methods

    Under and over the surface: a comparison of the use of leaked account credentials in the Dark and Surface Web

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    The world has seen a dramatic increase in cybercrime, in both the Surface Web, which is the portion of content on the World Wide Web that may be indexed by popular engines, and lately in the Dark Web, a portion that is not indexed by conventional search engines and is accessed through network overlays such as the Tor network. For instance, theft of online service credentials is an emerging problem, especially in the Dark Web, where the average price for someone\u2019s online identity is \ua3820. Previous research studied the modus operandi of criminals that obtain stolen account credentials through Surface Web outlets. As part of an effort to understand how the same crime unfolds in the Surface Web and the Dark Web, this study seeks to compare the modus operandi of criminals acting on both by leaking Gmail honey accounts in Dark Web outlets. The results are compared to a previous similar experiment performed in the Surface Web. Simulating operating activity of criminals, we posted 100 Gmail account credentials on hidden services on the Dark Web and monitored the activity that they attracted using a honeypot infrastructure. More specifically, we analysed the data generated by the two experiments to find differences in the activity observed with the aim of understanding how leaked credentials are used in both Web environments. We observed that different types of malicious activity happen on honey accounts depending on the Web environment they are released on. Our results can provide the research community with insights into how stolen accounts are being manipulated in the wild for different Web environments

    A Nonionic Alcohol Soluble Polymer Cathode Interlayer Enables Efficient Organic and Perovskite Solar Cells

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    The choice of interfacial materials and their properties play a critical role in determining solar cell performance and stability. For compatibility with roll-to-roll printing, it is desirable to develop stable cathode interface layers (CILs) that can be processed over the photoactive layer using orthogonal solvents. In this study, an n-type naphthalene diimide core and oligo (ethylene glycol) side-chain-based conjugated polymer is reported as a universal, efficient CIL for organic and perovskite photovoltaics. Besides good thermal stability and easy processing in alcohol/water, the new CIL is found to possess electron transport properties with an electrical conductivity of 2.3 × 10^{–6} S cm^{–1}, enabling its use as a CIL with a film thickness of up to ∼35(±2) nm. Utilizing the new CIL, 16% power conversion efficiency (PCE) is achieved for organic solar cells (OSCs) based on the PM6-Y6 photoactive layer (8.9% PCE for no CIL and 15.1% with state-of-the-art CIL, PDINO), and perovskite solar cells from methylammonium lead iodide yielded a PCE of 17.6%. Compared to the reference devices, the new CIL reduced trap-assisted carrier recombination and increased the built-in potential by 80 mV, simultaneously enhancing all photovoltaic parameters. Moreover, new CIL based devices had better photostability with no burn-in losses

    Graphene catalyzes the reversible formation of a C–C bond between two molecules

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    Carbon deposits are well-known inhibitors of transition metal catalysts. In contrast to this undesirable behavior, here we show that epitaxial graphene grown on Ru(0001) promotes the reversible formation of a C–C bond between −CH2CN and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ). The catalytic role of graphene is multifaceted: First, it allows for an efficient charge transfer between the surface and the reactants, thus favoring changes in carbon hybridization; second, it holds the reactants in place and makes them reactive. The reaction is fully reversible by injecting electrons with an STM tip on the empty molecular orbitals of the product. The making and breaking of the C–C bond is accompanied by the switching off and on of a Kondo resonance, so that the system can be viewed as a reversible magnetic switch controlled by a chemical reactionJ.J.N., F.C., R.M., and A.L.V.d.P. acknowledge the Ministerio de Economía y Competitividad (MINECO) project FIS2015-67367-C2-1-P and Comunidad de Madrid projects MAD2D P2013/MIT-3007 and Nanofrontmag S2013/MIT-2850. M.P., C.D., and F.M. acknowledge the MINECO project FIS2016-77889-R and computer time from the CCC-UAM and the Red Española de Supercomputación. C.D. acknowledges a Ramón y Cajal contract from MINECO (Spain). E.M.P., J.V., and B.N.-O. acknowledge the European Research Council project MINT, ERC-StG-2012-307609. IMDEA Nanoscience acknowledges support from the “Severo Ochoa” Programme for Centres of Excellence in R&D (MINECO, grant SEV-2016-0686). IFIMAC acknowledges support from the “María de Maeztu” Programme for Units of Excellence in R&D (MDM-2014-0377

    Backbone-driven host-dopant miscibility modulates molecular doping in NDI conjugated polymers

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    Molecular doping is the key to enabling organic electronic devices, however, the design strategies to maximize doping efficiency demands further clarity and comprehension. Previous reports focus on the effect of the side chains, but the role of the backbone is still not well understood. In this study, we synthesize a series of NDI-based copolymers with bithiophene, vinylene, and acetylenic moieties (P1G, P2G, and P3G, respectively), all containing branched triethylene glycol side chains. Using computational and experimental methods, we explore the impact of the conjugated backbone using three key parameters for doping in organic semiconductors: energy levels, microstructure, and miscibility. Our experimental results show that P1G undergoes the most efficient n-type doping owed primarily to its higher dipole moment, and better host–dopant miscibility with N-DMBI. In contrast, P2G and P3G possess more planar backbones than P1G, but the lack of long-range order, and poor host–dopant miscibility limit their doping efficiency. Our data suggest that backbone planarity alone is not enough to maximize the electrical conductivity (σ) of n-type doped organic semiconductors, and that backbone polarity also plays an important role in enhancing σ via host–dopant miscibility. Finally, the thermoelectric properties of doped P1G exhibit a power factor of 0.077 μW m−1 K−2, and ultra-low in-plane thermal conductivity of 0.13 W m−1K−1 at 5 mol% of N-DMBI, which is among the lowest thermal conductivity values reported for n-type doped conjugated polymers

    Antioxidant activity and characterization of whey protein-based beverages: Effect of shelf life and gastrointestinal transit on bioactivity

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    Whey proteins can exhibit antioxidant activity. The objectives of this study were to formulate model whey based beverages with well-established antioxidants (plant polyphenols, vitamins and astaxanthin) to investigate (1) the antioxidant shelf life over a 24-week period and (2) the antioxidant activity after upper gastrointestinal transit. Pilot scale processing (pasteurization, ultra-high temperature or spray drying) was used to prepare beverages which were representative of current product formats. In vitro gastrointestinal digestion of test samples was performed using the standardised INFOGEST method and antioxidant activity of samples was determined using ABTS, FRAP and ORAC. Results from the antioxidant shelf life study provided evidence that powder products functionality was preserved. Whey beverages (pasteurised or spray dried) increased or maintained antioxidant activity during gastrointestinal transit. Combination of whey with additional antioxidant ingredients increased the bioactivity of formulated products; however, this greater bioactivity was altered after gastrointestinal transit, depending on processing type and antioxidant methodology. Industrial relevance: Whey protein-based antioxidant beverages could benefit the elderly consumer to meet their increased protein requirements and boost their antioxidant status. Consumer's acceptance for whey protein-based beverages often improves with clear formulations. This work generated whey protein-based UHT beverages with greater stability and clarity than pasteurised formulations. A novel combination of plant and marine antioxidants increased antioxidant activity of whey protein-based formulations. Furthermore, to suit export markets this work generated spray dried whey protein formulations that did not alter antioxidant potentialThis work was funded by the Irish Department of Agriculture, Food and the Marine, FIRM 13F354-WheyGSH and 15F604-TOMI). A. R. Corrochano was in receipt of a Teagasc Walsh Fellowship. E. Arranz also received funding from Enterprise Ireland (MF2018-0151) and the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 71365

    Affordable laparoscopic simulator to acquire basic skills in undergraduate surgery students

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    Background: The simulation emerges as an option that allows students to practice in a safe environment, all this in a scenario that resembles the real situation.Methods: We developed a prototype of a low-cost simulator that mimics the dimensions of the abdominal cavity and allows the undergraduate students to acquire the basic skills in minimally invasive surgery.Results: In the 10 competencies evaluated, statistically significant improvement was found in both groups being higher in the students who were trained by our simulator of laparoscopic surgery compared with students who attended surgeries and participated as seconds assistants, taking as reference a value of p ≤0.05.Conclusions: The simulation as new teaching strategy generates a real environment and scenarios that can be recreated in multiple occasions, being able to change depending on the objectives for the acquisition of skills. This simulator gives the user skills for more types of simulation as it progresses in its surgical training
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