118 research outputs found

    The Importance of Mineralogical Knowledge in the Sustainability of Artisanal Gold Mining: A Mid-South Peru Case

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    Mineralogy and gold processing techniques from several mining areas of the Nazca-Ocoña gold belt, Mid-South Peru, were investigated to assess the efficiency of gold extraction methods in relation to their mineralogy. The deposits from this belt are intrusion gold related to mineralization in quartz veins. Native gold occurs as micrometric grains encapsulated in pyrite and in minor amounts in other sulfides and quartz. Electrum is found mainly in fractures of pyrite and attains up to 35 wt. % Ag. In addition to these occurrences, gold tellurides also occur and they are abundant in San Luis. Gold processing is carried out by amalgamation with mercury and/or cyanidation. The comparison of the gold grade in the mineralizations and in the residual tailings indicates that a significant amount of gold is not recovered using the mercury amalgamation process and also, in the case of the gold recovery by cyanidation, except when cement was added to the cyanide solution. This was due to an increase in the pH that favours the dissolution of the gold matrix. In the cyanidation process carried out in tailings previously treated with mercury, part of the mercury retained in them is released to the atmosphere or to the cyanidation fluid

    Mechano-Optical Analysis of Single Cells with Transparent Microcapillary Resonators

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    The study of biophysical properties of single cells is becoming increasingly relevant in cell biology and pathology. The measurement and tracking of magnitudes such as cell stiffness, morphology, and mass or refractive index have brought otherwise inaccessible knowledge about cell physiology, as well as innovative methods for high-throughput label-free cell classification. In this work, we present hollow resonator devices based on suspended glass microcapillaries for the simultaneous measurement of single-cell buoyant mass and reflectivity with a throughput of 300 cells/minute. In the experimental methodology presented here, both magnitudes are extracted from the devices' response to a single probe, a focused laser beam that enables simultaneous readout of changes in resonance frequency and reflected optical power of the devices as cells flow within them. Through its application to MCF-7 human breast adenocarcinoma cells and MCF-10A nontumorigenic cells, we demonstrate that this mechano-optical technique can successfully discriminate pathological from healthy cells of the same tissue type

    Biophysical properties of single rotavirus particles account for the functions of protein shells in a multilayered virus

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    The functions performed by the concentric shells of multilayered dsRNA viruses require specific protein interactions that can be directly explored through their mechanical properties. We studied the stiffness, breaking force, critical strain and mechanical fatigue of individual Triple, Double and Single layered rotavirus (RV) particles. Our results, in combination with Finite Element simulations, demonstrate that the mechanics of the external layer provides the resistance needed to counteract the stringent conditions of extracellular media. Our experiments, in combination with electrostatic analyses, reveal a strong interaction between the two outer layers and how it is suppressed by the removal of calcium ions, a key step for transcription initiation. The intermediate layer presents weak hydrophobic interactions with the inner layer that allow the assembly and favor the conformational dynamics needed for transcription. Our work shows how the biophysical properties of the three shells are finely tuned to produce an infective RV virio

    Correction: Russo, B., et al. Assessment of urban flood resilience in barcelona for current and future scenarios. the resccue project. (Sustainability 2020, 12, 5638)

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    The authors would like to make the following corrections about the published paper [1]. The changes are as follows: (1) Replacing Table 4. Reference 1. Russo, B.; Velasco, M.; Locatelli, L.; Sunyer, D.; Yubero, D.; Monjo, R.; Martínez-Gomariz, E.; Forero-Ortiz, E.; Sånchez-Muñoz, D.; Evans, B.; et al. Assessment of Urban Flood Resilience in Barcelona for Current and Future Scenarios. The RESCCUE Project. Sustainability 2020, 12, 5638. [CrossRef]

    Morphological evolution of pulsed laser deposited ZrO2 thin films

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    Morphological evolution of ZrO2 thin films deposited during pulsed laser deposition of Zr in O2 atmosphere has been experimentally studied at two different film deposition temperatures, 300 and 873 K. The roughness exponent, , the growth exponent, , the coarsening exponent, 1/z, and the exponent defining the evolution of the characteristic wavelength of the surface, p, for depositions at 300 K amounted to = 1.00.1, = 0.40.1, 1/z= 0.340.03, and p= 0.490.03, whereas for depositions carried out at 873 K amounted to = 0.30.3, = 0.40.2, and 1/z= 0.00.2. Experimental error becomes important due to the flat morphology of the films inherent to the deposition technique. The change in the surface topography with the film temperature has been studied with the help of a simple Monte Carlo model which indicates the existence of two different growth regimes: a shadowing dominated growth, occurring at low temperatures, characterized by calculated values = 1.000.04, = 0.500.04, p= 0.460.01, and 1/z= 0.350.02 and a diffusion dominated growth that takes place at high temperatures as well as at low deposition rates, characterized by calculated values = 0.150.08, = 0.330.04, and 1/z= 0.330.07. The good agreement obtained between the experimental and simulated parameters is discussed within the frame of the general characteristics of the deposition method.Universidad Nacional Autónoma de México-PAPIIT-IN107808Consejo Nacional de Ciencia y Tecnología de México-CONACyT-50203-FMinisterio de Ciencia, Innovación y Universidades de España-MAT 2007-65764, PIE 200960I132 y CONSOLIDER INGENIO 2010-CSD2008-00023Junta de Andalucía-TEP2275 y P07-FQM-0329

    Optomechanical devides for mechanobiological fingerprinting

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    Resumen del trabajo presentado en el Frontiers of Nanomechanical Systems (FSN2021), celebraod de forma virtual del 19 al 21 de enero de 2021Twenty years have passed since the first detection of biomolecular recognition using micromechanical systems[1]. In the last two decades, micro- nanomechanical systems have been refined to achieve amazing detection limits in force and mass that have enabled different schemes for ultrasensitive measurements of biological interactions as well as new ways of biological spectrometry. More recently, these figures of merit have been improved by coupling optical cavities to mechanical systems. In this talk, I will review the use of micro- nanomechanical systems for mechanobiological fingerprinting of biological entities, particularizing in the contributions of our group [2]. An essential core of this topic is the discussion about the mechanical coupling between a biological particle and a mechanical resonator, an issue that it is has been often oversimplified. We show that the biomechanical coupling that emerges between a bioparticle and a mechanical resonator is more complex than previously expect and it can give rise to different interaction regimes, in which the resonator response is dominated by different physical parameters of the analyte [3-4]. In particular, we will show experiments done with a variety of micro- nano- optomechanical systems using different measurement schemes where the mass, the stiffness and even the vibration modes of single biological entities can be measured with high sensitivity. It is now widely appreciated the essential role of mechanics in relevant biological processes and how disease can be revealed as changes in the mechanical properties of biological matter. I am pretty sure that future developments in optomechanical devices will contribute for major understanding of diseases as well as for new avenues in diagnosis and therapy

    Evaluation of receptor and chemical transport models for PM10 source apportionment

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    In this study, the performance of two types of source apportionment models was evaluated by assessing the results provided by 40 different groups in the framework of an intercomparison organised by FAIRMODE WG3 (Forum for air quality modelling in Europe, Working Group 3). The evaluation was based on two performance indicators: z-scores and the root mean square error weighted by the reference uncertainty (RMSEu), with pre-established acceptability criteria. By involving models based on completely different and independent input data, such as receptor models (RMs) and chemical transport models (CTMs), the intercomparison provided a unique opportunity for their cross-validation. In addition, comparing the CTM chemical profiles with those measured directly at the source contributed to corroborate the consistency of the tested model results. The most commonly used RM was the US EPA- PMF version 5. RMs showed very good performance for the overall dataset (91% of z-scores accepted) while more difficulties were observed with the source contribution time series (72% of RMSEu accepted). Industrial activities proved to be the most difficult sources to be quantified by RMs, with high variability in the estimated contributions. In the CTMs, the sum of computed source contributions was lower than the measured gravimetric PM10 mass concentrations. The performance tests pointed out the differences between the two CTM approaches used for source apportionment in this study: brute force (or emission reduction impact) and tagged species methods. The sources meeting the z-score and RMSEu acceptability criteria tests were 50% and 86%, respectively. The CTM source contributions to PM10 were in the majority of cases lower than the RM averages for the corresponding source. The CTMs and RMs source contributions for the overall dataset were more comparable (83% of the z-scores accepted) than their time series (successful RMSEu in the range 25% - 34%). The comparability between CTMs and RMs varied depending on the source: traffic/exhaust and industry were the source categories with the best results in the RMSEu tests while the most critical ones were soil dust and road dust. The differences between RMs and CTMs source reconstructions confirmed the importance of cross validating the results of these two families of models

    Design, characterization and installation of the NEXT-100 cathode and electroluminescence regions

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    NEXT-100 is currently being constructed at the Laboratorio Subterr\'aneo de Canfranc in the Spanish Pyrenees and will search for neutrinoless double beta decay using a high-pressure gaseous time projection chamber (TPC) with 100 kg of xenon. Charge amplification is carried out via electroluminescence (EL) which is the process of accelerating electrons in a high electric field region causing secondary scintillation of the medium proportional to the initial charge. The NEXT-100 EL and cathode regions are made from tensioned hexagonal meshes of 1 m diameter. This paper describes the design, characterization, and installation of these parts for NEXT-100. Simulations of the electric field are performed to model the drift and amplification of ionization electrons produced in the detector under various EL region alignments and rotations. Measurements of the electrostatic breakdown voltage in air characterize performance under high voltage conditions and identify breakdown points. The electrostatic deflection of the mesh is quantified and fit to a first-principles mechanical model. Measurements were performed with both a standalone test EL region and with the NEXT-100 EL region before its installation in the detector. Finally, we describe the parts as installed in NEXT-100, following their deployment in Summer 2023.Comment: 35 pages, 25 Figures, update includes accepted version in JINS

    Proteome from patients with metabolic syndrome is regulated by quantity and quality of dietary lipids

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    Background: Metabolic syndrome is a multi-component disorder associated to a high risk of cardiovascular disease. Its etiology is the result of a complex interaction between genetic and environmental factors, including dietary habits. We aimed to identify the target proteins modulated by the long-term consumption of four diets differing in the quality and quantity of lipids in the whole proteome of peripheral blood mononuclear cells (PBMC). Results: A randomized, controlled trial conducted within the LIPGENE study assigned 24 MetS patients for 12 weeks each to 1 of 4 diets: a) high-saturated fatty acid (HSFA), b) high-monounsaturated fatty acid (HMUFA), c) low-fat, high-complex carbohydrate diets supplemented with placebo (LFHCC) and d) low-fat, high-complex carbohydrate diets supplemented with long chain (LC) n-3 polyunsaturated fatty acids (PUFA) (LFHCC n-3). We analyzed the changes induced in the proteome of both nuclear and cytoplasmic fractions of PBMC using 2-D proteomic analysis. Sixty-seven proteins were differentially expressed after the long-term consumption of the four diets. The HSFA diet induced the expression of proteins responding to oxidative stress, degradation of ubiquitinated proteins and DNA repair. However, HMUFA, LFHCC and LFHCC n-3 diets down-regulated pro-inflammatory and oxidative stress-related proteins and DNA repairing proteins. Conclusion: The long-term consumption of HSFA, compared to HMUFA, LFHCC and LFHCC n-3, seems to increase the cardiovascular disease (CVD) risk factors associated with metabolic syndrome, such as inflammation and oxidative stress, and seem lead to DNA damage as a consequence of high oxidative stress

    XELOX (capecitabine plus oxaliplatin) as first-line treatment for elderly patients over 70 years of age with advanced colorectal cancer

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    The purpose of this phase II trial was to determine the efficacy and safety of the XELOX (capecitabine/oxaliplatin) regimen as first-line therapy in the elderly patients with metastatic colorectal cancer (MCRC). A total of 50 patients with MCRC aged â©Ÿ70 years received oxaliplatin 130 mg m−2 on day 1 followed by oral capecitabine 1000 mg m−2 twice daily on days 1–14 every 3 weeks. Patients with creatinine clearance 30–50 ml min−1 received a reduced dose of capecitabine (750 mg m−2 twice daily). By intent-to-treat analysis, the overall response rate was 36% (95% CI, 28–49%), with three (6%) complete and 15 (30%) partial responses. In total, 18 patients (36%) had stable disease and 14 (28%) progressed. The median times to disease progression and overall survival were 5.8 months (95% CI, 3.9–7.8 months) and 13.2 months (95% CI, 7.6–16.9 months), respectively. Capecitabine was well tolerated: grade 3/4 adverse events were observed in 14 (28%) patients: 11 (22%) diarrhoea, eight (16%) asthenia, seven (14%) nausea/vomiting, three (6%) neutropenia, three (6%) thrombocytopenia, and two (4%) hand–foot syndrome. There was one treatment-related death from diarrhoea and sepsis. In conclusion, XELOX is well tolerated in elderly patients, with respectable efficacy and a meaningful clinical benefit response. Given its ease of administration compared with combinations of oxaliplatin with 5-FU/LV, it represents a good therapeutic option in the elderly
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