105 research outputs found

    Broadband telecom transparency of semiconductor-coated metal nanowires: more transparent than glass

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    Metallic nanowires (NW) coated with a high permittivity dielectric are proposed as means to strongly reduce the light scattering of the conducting NW, rendering them transparent at infrared wavelengths of interest in telecommunications. Based on a simple, universal law derived from electrostatics arguments, we find appropriate parameters to reduce the scattering efficiency of hybrid metal-dielectric NW by up to three orders of magnitude as compared with the scattering efficiency of the homogeneous metallic NW. We show that metal@dielectric structures are much more robust against fabrication imperfections than analogous dielectric@metal ones. The bandwidth of the transparent region entirely covers the near IR telecommunications range. Although this effect is optimum at normal incidence and for a given polarization, rigorous theoretical and numerical calculations reveal that transparency is robust against changes in polarization and angle of incidence, and also holds for relatively dense periodic or random arrangements. A wealth of applications based on metal-NWs may benefit from such invisibility

    Testing postcombustion CO2 capture with CaO in a 1.7 MWt pilot facility

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    AbstractCalcium looping, CaL, is a new and rapidly developing technology that makes use of CaO as a high temperature regenerable sorbent of CO2. Previous theoretical and lab scale studies have shown that this technology could lead to a substantial reduction in the cost of CO2 capture and energy penalties because heat can be effectively recovered from this high temperature solid looping system. We report in this paper on the first results from a pilot plant designed to demonstrate the viability of postcombustion capture of CO2 using CaL under conditions comparable to those expected in a large scale plant. The pilot includes two interconnected circulating fluidized bed reactors of 15 m height: a CO2 absorber (carbonator) able to treat up to 2400kg/h (equivalent to about 1.7 MWth), and an oxy-fired CFB calciner with a firing power between 1-3 MWth. CO2 capture efficiencies over 90% have been experimentally observed, including continuous operation with highly cycled solids in the system (i.e. with modest CO2 carrying capacities). SO2 capture is shown to be extremely high, with concentrations of SO2 well below 10 ppmv at the exit of the carbonator. Closure of carbon and sulfur balances is satisfactory. These results should be valuable base for model validation and scaling up purposes in future stages of the EU FP7 “CaOling” project, under which this investigation has been carried out

    Development of sandwich ELISA and lateral flow immunoassay to detect almond in processed food

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    Almond (Prunus dulcis) represents a potential allergenic hazard that should be included in Allergen Control Plans. In this study, sandwich ELISA and lateral flow immunoassay (LFIA), using amandin (Pru du 6) as the target protein, were developed to detect almond in processed food and validated according to international guides. ELISA could detect 2 ng/mL and LFIA 30 ng/mL of pure amandin. No cross-reactivity was found on a panel of 50 food commodities with the exception of Pecan nut, Brazil nut and chestnut for which the cross-reactivity was lower than 0.02%. Furthermore, ELISA and LFIA were able to detect 0.12 and 0.70 ppm of almond protein in foods spiked with almond extract whereas 0.20 and 2.0 ppm could be detected in baked cookies incurred with almond, respectively. Both techniques could be applied for food manufacturers and control agencies for monitoring the presence of almond traces in food and working surfaces. © 2021 The Author(s

    Strategies for penicillin V dendronization with cationic carbosilane dendrons and study of antibacterial properties.

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    Strategies to synthesize a cationic carbosilane dendron containing the antibiotic penicillin V potassium salt (PenVK) at the focal point are discussed. The preparation of such a compound requires the use of systems with no donor atoms such as N or S in their framework, because their presence favours the rupture of the penicillin beta-lactam ring. The antibacterial activity of the new dendron containing ammonium groups, at the periphery, and the PenV moiety, at the focal point, against gram-positive Staphylococcus aureus strains was evaluated. These results were compared with those obtained for free PenVK, a related cationic dendron without a penicillin moiety at the focal point, and also compared with an equimolar mixture of this last dendron with free PenV. The data obtained indicate that, on one hand, the conjugation or interaction of PenV with cationic dendrons reduces its activity in comparison with free PenVK. On the other hand, the penicillin dendron is able to release the antibiotic in the presence of esterease, due to the breaking of the ester bond in this derivative.Ministerio de Economía y Empres

    Clinical Characteristics and Long-term outcomes of patients undergoing combined heart-kidney transplantation: a single-center experience

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    [Abstract] Background. The purpose of the study was to describe clinical characteristics and long-term survival of patients undergoing combined heart-kidney transplant in a single center. Methods. We conducted a retrospective analysis of 22 consecutive patients who underwent combined heart-kidney transplant at our institution between 1995 and 2013. Long-term outcomes were analyzed by means of the Kaplan-Meier method. Results. Four patients underwent re-do transplant (2 cardiac re-transplants, 1 kidney re-transplant, and 1 combined heart-kidney re-transplant). Most frequent underlying cardiac conditions were coronary artery disease (54%), dilated cardiomyopathy (23%), and chronic rejection of a previous heart graft (18%). Known causes of chronic renal dysfunction were nephroangioesclerosis (23%), drug-related toxicity (14%), and Wegener granulomatosis (5%). Non-specified chronic renal dysfunction was present in 50% patients. In-hospital postoperative mortality rate was 5 of 22 (23%). Causes of early death were directly related to kidney transplant surgery in 4 of 5 (80%) patients. Among the remaining 17 patients who surmounted the postoperative period, long-term survival rates 1 year, 5 years, and 10 years after HKT were 88%, 82%, and 65%, respectively. Over a mean follow-up of 6.7 ± 6.4 years, cumulative incidences of cytomegalovirus infection, coronary allograft vasculopathy, malignancy, and acute cardiac graft rejection were 41%, 6%, 24%, and 41%, respectively. There was no episode of acute renal graft rejection. At the end of follow-up, all survivors (n = 11) were in functional New York Heart Association class I. Mean creatinine serum level was 1.68 mg/dL. Conclusions. In our experience, combined heart-kidney transplant is a feasible therapeutic option that yielded favorable long-term outcomes, with a low cumulative incidence of cardiac graft dysfunction. These results were obtained at the expense of a significant risk of early postoperative mortality, which was mainly related to complications of kidney transplant surgery

    Structure-activity relationship study of cationic carbosilane dendritic systems as antibacterial agents

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    This work focuses on the antibacterial activity against Gram-positive Staphylococcus aureus and Gramnegative Escherichia coli and the hemolytic properties of two types of ammonium cationic carbosilane systems: dendrimers and dendrons. The effects of: i) the generation, ii) the type of peripheral groups near the cationic charges (a SiMe2 moiety or a S atom depending on the synthetic procedure, hydrosilylation or thiol-ene addition, respectively), iii) the core of dendrimers (polyphenoxo vs. Si atom) and iv) the focal point of dendrons (-N3, -NH2, -OH) have been assessed. The structure-activity relationship analysis indicates the importance of an adequate balance between the hydrophilic and lipophilic fragments of these molecules to reach the best antibacterial activity. Regarding hemolysis, lowest toxicity values were registered for dendritic systems with a sulfur atom close to the surface and, in the particular case of dendrons, for those with a hydroxyl focal point. One dendrimer and one dendron, both bearing a sulfur atom close to the surface, scored best in the activity-toxicity relationship analysis and were chosen for resistance assays. No changes in the inhibitory and bactericidal capacity in the case of the dendron and only a slight increase of these values for the dendrimer were observed after 15 subculture cycles. Furthermore, these two compounds stayed active towards different strains of resistant bacteria and avoid formation of biofilm at concentrations over the minimum inhibitory concentration (MIC).Ministerio de Economía y Empres

    Twitter as a Tool for Teaching and Communicating Microbiology: The #microMOOCSEM Initiative

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    Online social networks are increasingly used by the population on a daily basis. They are considered a powerful tool for science communication and their potential as educational tools is emerging. However, their usefulness in academic practice is still a matter of debate. Here, we present the results of our pioneering experience teaching a full Basic Microbiology course via Twitter (#microMOOCSEM), consisting of 28 lessons of 40-45 minutes duration each, at a tweet per minute rate during 10 weeks. Lessons were prepared by 30 different lecturers, covering most basic areas in Microbiology and some monographic topics of general interest (malaria, HIV, tuberculosis, etc.). Data analysis on the impact and acceptance of the course were largely affirmative, promoting a 330% enhancement in the followers and a >350-fold increase of the number of visits per month to the Twitter account of the host institution, the Spanish Society for Microbiology. Almost one third of the course followers were located overseas. Our study indicates that Massive Online Open Courses (MOOC) via Twitter are highly dynamic, interactive, and accessible to great audiences, providing a valuable tool for social learning and communicating science. This strategy attracts the interest of students towards particular topics in the field, efficiently complementing customary academic activities, especially in multidisciplinary areas like Microbiology.Versión del edito

    2013. Documento Sevilla de Consenso sobre Alternativas a la Transfusión de Sangre Alogénica. Actualización del Documento Sevilla

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    La transfusión de sangre alogénica (TSA) no es inocua, y como consecuencia han surgido múltiples alternativas a la misma (ATSA). Existe variabilidad respecto a las indicaciones y buen uso de las ATSA. Dependiendo de la especialidad de los médicos que tratan a los pacientes, el grado de anemia, la política transfusional, la disponibilidad de las ATSA y el criterio personal, estas se usan de forma variable. Puesto que las ATSA tampoco son inocuas y pueden no cumplir criterios de coste-efectividad, la variabilidad en su uso es inaceptable. Las sociedades españolas de Anestesiología y Reanimación (SEDAR), Hematología y Hemoterapia (SEHH), Farmacia Hospitalaria (SEFH), Medicina Intensiva y Unidades Coronarias (SEMICYUC), Trombosis y Hemostasia (SETH) y Transfusiones Sanguíneas (SETS) han elaborado un documento de consenso para el buen uso de la ATSA. Un panel de expertos de las 6 sociedades ha llevado a cabo una revisión sistemática de la literatura médica y elaborado el 2013. Documento Sevilla de Consenso sobre Alternativas a la Transfusión de Sangre Alogénica. Solo se contempla las ATSA dirigidas a disminuir la transfusión de concentrado de hematíes. Se definen las ATSA como toda medida farmacológica y no farmacológica encaminada a disminuir la transfusión de concentrado de hematíes, preservando siempre la seguridad del paciente. La cuestión principal que se plantea en cada ítem se formula, en forma positiva o negativa, como: «La ATSA en cuestión reduce/no reduce la tasa transfusional». Para formular el grado de recomendación se ha usado la metodología Grades of Recommendation Assessment, Development and Evaluation (GRADE)

    SARS-CoV-2 viral load in nasopharyngeal swabs is not an independent predictor of unfavorable outcome

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    The aim was to assess the ability of nasopharyngeal SARS-CoV-2 viral load at first patient’s hospital evaluation to predict unfavorable outcomes. We conducted a prospective cohort study including 321 adult patients with confirmed COVID-19 through RT-PCR in nasopharyngeal swabs. Quantitative Synthetic SARS-CoV-2 RNA cycle threshold values were used to calculate the viral load in log10 copies/mL. Disease severity at the end of follow up was categorized into mild, moderate, and severe. Primary endpoint was a composite of intensive care unit (ICU) admission and/or death (n = 85, 26.4%). Univariable and multivariable logistic regression analyses were performed. Nasopharyngeal SARS-CoV-2 viral load over the second quartile (≥ 7.35 log10 copies/mL, p = 0.003) and second tertile (≥ 8.27 log10 copies/mL, p = 0.01) were associated to unfavorable outcome in the unadjusted logistic regression analysis. However, in the final multivariable analysis, viral load was not independently associated with an unfavorable outcome. Five predictors were independently associated with increased odds of ICU admission and/or death: age ≥ 70 years, SpO2, neutrophils > 7.5 × 103/µL, lactate dehydrogenase ≥ 300 U/L, and C-reactive protein ≥ 100 mg/L. In summary, nasopharyngeal SARS-CoV-2 viral load on admission is generally high in patients with COVID-19, regardless of illness severity, but it cannot be used as an independent predictor of unfavorable clinical outcome

    Dendritic cell deficiencies persist seven months after SARS-CoV-2 infection

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    Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV)-2 infection induces an exacerbated inflammation driven by innate immunity components. Dendritic cells (DCs) play a key role in the defense against viral infections, for instance plasmacytoid DCs (pDCs), have the capacity to produce vast amounts of interferon-alpha (IFN-α). In COVID-19 there is a deficit in DC numbers and IFN-α production, which has been associated with disease severity. In this work, we described that in addition to the DC deficiency, several DC activation and homing markers were altered in acute COVID-19 patients, which were associated with multiple inflammatory markers. Remarkably, previously hospitalized and nonhospitalized patients remained with decreased numbers of CD1c+ myeloid DCs and pDCs seven months after SARS-CoV-2 infection. Moreover, the expression of DC markers such as CD86 and CD4 were only restored in previously nonhospitalized patients, while no restoration of integrin β7 and indoleamine 2,3-dyoxigenase (IDO) levels were observed. These findings contribute to a better understanding of the immunological sequelae of COVID-19
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