114 research outputs found

    Diversity and conservational status of vascular plants of "Sierra de las Quijadas" National Park (San Luis, Argentina)

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    The "Sierra de las Quijadas" National Park, located in the NW of San Luis province, covers 150,252 hectares and preserves a sample of the Chaco-Monte ecotone, with communities of the "Dry Chaco", and "Monte" ecoregions (partly "Monte of plains and plateaus" and partly "Monte of Sierras and bolsons"). It includes mixed forests, shrubby steppes, groves and galleries, rings of halophytes, "pajonales" and rushes. Our goals were to inventory and analyze the vascular flora as well as to identify the endemisms that require greater protection. We recorded 356 species distributed in 208 genera of 58 plant families. Eight taxa are new records for the native vascular flora of the province of San Luis. While 120 taxa are endemic to Argentina, four species turned out to be exclusive of the Park and surroundings: Atriplex quixadensis (Chenopodiaceae), Senecio hualtaranensis (Asteraceae), Sclerophylax difulvioi (Solanaceae) and Gomphrena colosacana var. andersonii (Amaranthaceae). These taxa suffer varying degrees of threat from population restriction, intense erosion and anthropic action: 3 are critically endangered (CR), other 3 are endangered (EN), 10 are vulnerable (VU), 25 near threatened (NT) and 79 cause minor concern (LC), requiring in many cases immediate and continued protection. Dicotyledons (74%) and Monocotyledons (25%) predominate, plus 2 Monilophyta species and 3 Gymnospermae. The six best represented families are Poaceae, Asteraceae, Fabaceae, Solanaceae, Verbenaceae and Bromeliaceae, which account for 56% of the species. Phanerophytes and Hemicryptophytes life-forms reach 24% each, followed by Chamaephytes (22%) and Therophytes (16%). This reveals a remarkable adaptation of the flora to the long dry season. Highlights A first check-list of the vascular flora of the Sierra de las Quijadas National Park is presented, in the ecotone Dry Chaco and Monte, one of the most arid places in Argentina. The Park preserves 356 species and 99 infraspecific taxa (3.6% of the Argentinean flora). Eight of them are new records for the province of San Luis. Stand out 4 species that are unique to the Park, of which 3 are critically endangered (CR) and the remaining one is vulnerable (VU). Another 116 species are endemic to Argentina, including 3 endangered (EN), 9 vulnerable (VU), and 25 almost threatened (NT) with extinction. The prevalence of chamaephytes, hemicryptophytes, cryptophytes and therophytes (70%) reveal the high degree of adaptation to the prolonged dry season.The "Sierra de las Quijadas" National Park, located in the NW of San Luis province, covers 150,252 hectares and preserves a sample of the Chaco-Monte ecotone, with communities of the "Dry Chaco", and "Monte" ecoregions (partly "Monte of plains and plateaus" and partly "Monte of Sierras and bolsons"). It includes mixed forests, shrubby steppes, groves and galleries, rings of halophytes, "pajonales" and rushes. Our goals were to inventory and analyze the vascular flora as well as to identify the endemisms that require greater protection. We recorded 356 species distributed in 208 genera of 58 plant families. Eight taxa are new records for the native vascular flora of the province of San Luis. While 120 taxa are endemic to Argentina, four species turned out to be exclusive of the Park and surroundings: Atriplex quixadensis (Chenopodiaceae), Senecio hualtaranensis (Asteraceae), Sclerophylax difulvioi (Solanaceae) and Gomphrena colosacana var. andersonii (Amaranthaceae). These taxa suffer varying degrees of threat from population restriction, intense erosion and anthropic action: 3 are critically endangered (CR), other 3 are endangered (EN), 10 are vulnerable (VU), 25 near threatened (NT) and 79 cause minor concern (LC), requiring in many cases immediate and continued protection. Dicotyledons (74%) and Monocotyledons (25%) predominate, plus 2 Monilophyta species and 3 Gymnospermae. The six best represented families are Poaceae, Asteraceae, Fabaceae, Solanaceae, Verbenaceae and Bromeliaceae, which account for 56% of the species. Phanerophytes and Hemicryptophytes life-forms reach 24% each, followed by Chamaephytes (22%) and Therophytes (16%). This reveals a remarkable adaptation of the flora to the long dry season. Highlights A first check-list of the vascular flora of the Sierra de las Quijadas National Park is presented, in the ecotone Dry Chaco and Monte, one of the most arid places in Argentina. The Park preserves 356 species and 99 infraspecific taxa (3.6% of the Argentinean flora). Eight of them are new records for the province of San Luis. Stand out 4 species that are unique to the Park, of which 3 are critically endangered (CR) and the remaining one is vulnerable (VU). Another 116 species are endemic to Argentina, including 3 endangered (EN), 9 vulnerable (VU), and 25 almost threatened (NT) with extinction. The prevalence of chamaephytes, hemicryptophytes, cryptophytes and therophytes (70%) reveal the high degree of adaptation to the prolonged dry season

    Diagnóstico de las condiciones del trabajo; de las percepciones, valoraciones y vivencias sobre dichas condiciones por parte de los trabajadores del sector agrario en Gran La Plata : Informe de investigación

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    Esta investigación ha sido realizada en el marco del convenio establecido entre la Facultad de Trabajo Social – UNLP y Registro Nacional de Trabajadores y Empleadores Agropecuarios (RENATEA) con fecha 5 de agosto de 2015. A partir de las políticas laborales aplicadas desde 2003 en Argentina, uno de los sectores que requirió una atención especial fue el del sector rural. En este marco, se ha promulgado en 2011 la Ley 26.727, que amplía los derechos de los trabajadores agrarios. El propósito de dicho estudio fue generar conocimiento sobre las condiciones y medio ambiente de trabajo que actualmente caracterizan al sector agrario en Gran La Plata, con el fin de poder aplicarlo en la definición de políticas y de estrategias de intervención que permitan mejorar dichas condiciones laborales y a la vez, de transferir este conocimiento a los mismos trabajadores y a sus organizaciones. Asimismo, en esta investigación se han estudiado a las trayectorias laborales de los trabajadores, así como las percepciones y valoraciones que los trabajadores conforman sobre sus propias condiciones de trabajo. La metodología aplicada en esta investigación es cualitativa. Se han realizado entrevistas en profundidad con base a una guía de pautas especialmente diseñada para este estudio a trabajadores que se desempeñan en la actividad rural en Abasto, Etcheverry y El Peligro, Gran La Plata, aplicando muestreo no probabilístico bajo el criterio de muestreo teórico. El trabajo de campo fue desarrollado desde 3 de noviembre hasta el 4 de diciembre de 2015.Facultad de Trabajo Socia

    High-throughput screening method for discovering CatSper inhibitors using membrane depolarization caused by external calcium chelation and fluorescent cell barcoding

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    The exclusive expression of CatSper in sperm and its critical role in sperm function makes this channel an attractive target for contraception. The strategy of blocking CatSper as a male, non-hormonal contraceptive has not been fully explored due to the lack of robust screening methods to discover novel and specific inhibitors. The reason for this lack of appropriate methodology is the structural and functional complexity of this channel. We have developed a high-throughput method to screen drugs with the capacity to block CatSper in mammalian sperm. The assay is based on removing external free divalent cations by chelation, inducing CatSper to efficiently conduct monovalent cations. Since Na+ is highly concentrated in the extracellular milieu, a sudden influx depolarizes the cell. Using CatSper1 KO sperm we demonstrated that this depolarization depends on CatSper function. A membrane potential (Em) assay was combined with fluorescent cell barcoding (FCB), enabling higher throughput flow cytometry based on unique fluorescent signatures of different sperm samples. These differentially labeled samples incubated in distinct experimental conditions can be combined into one tube for simultaneous acquisition. In this way, acquisition times are highly reduced, which is essential to perform larger screening experiments for drug discovery using live cells. Altogether, a simple strategy for assessing CatSper was validated, and this assay was used to develop a high-throughput drug screening for new CatSper blockers.Fil: Luque, Guillermina Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Schiavi Ehrenhaus, Liza Jamaica. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Jabloñski, Martina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Balestrini, Paula Ania. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Novero, Analia Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Torres, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; ArgentinaFil: Osycka Salut, Claudia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Biotecnológicas. Universidad Nacional de San Martín. Instituto de Investigaciones Biotecnológicas; ArgentinaFil: Darszon, Alberto. Universidad Autónoma del Estado de México; MéxicoFil: Krapf, Dario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Buffone, Mariano Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental. Fundación de Instituto de Biología y Medicina Experimental. Instituto de Biología y Medicina Experimental; Argentin

    Localization of anatomical changes in patients during proton therapy with in-beam PET monitoring: a voxel-based morphometry approach exploiting Monte Carlo simulations

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    Purpose: In-beam positron emission tomography (PET) is one of the modalities that can be used for in vivo noninvasive treatment monitoring in proton therapy. Although PET monitoring has been frequently applied for this purpose, there is still no straightforward method to translate the information obtained from the PET images into easy-to-interpret information for clinical personnel. The purpose of this work is to propose a statistical method for analyzing in-beam PET monitoring images that can be used to locate, quantify, and visualize regions with possible morphological changes occurring over the course of treatment. Methods: We selected a patient treated for squamous cell carcinoma (SCC) with proton therapy, to perform multiple Monte Carlo (MC) simulations of the expected PET signal at the start of treatment, and to study how the PET signal may change along the treatment course due to morphological changes. We performed voxel-wise two-tailed statistical tests of the simulated PET images, resembling the voxel-based morphometry (VBM) method commonly used in neuroimaging data analysis, to locate regions with significant morphological changes and to quantify the change. Results: The VBM resembling method has been successfully applied to the simulated in-beam PET images, despite the fact that such images suffer from image artifacts and limited statistics. Three dimensional probability maps were obtained, that allowed to identify interfractional morphological changes and to visualize them superimposed on the computed tomography (CT) scan. In particular, the characteristic color patterns resulting from the two-tailed statistical tests lend themselves to trigger alarms in case of morphological changes along the course of treatment. Conclusions: The statistical method presented in this work is a promising method to apply to PET monitoring data to reveal interfractional morphological changes in patients, occurring over the course of treatment. Based on simulated in-beam PET treatment monitoring images, we showed that with our method it was possible to correctly identify the regions that changed. Moreover we could quantify the changes, and visualize them superimposed on the CT scan. The proposed method can possibly help clinical personnel in the replanning procedure in adaptive proton therapy treatments

    Variability and reproducibility of multi-echo T2 relaxometry: Insights from multi-site, multi-session and multi-subject MRI acquisitions

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    Quantitative magnetic resonance imaging (qMRI) can increase the specificity and sensitivity of conventional weighted MRI to underlying pathology by comparing meaningful physical or chemical parameters, measured in physical units, with normative values acquired in a healthy population. This study focuses on multi-echo T2 relaxometry, a qMRI technique that probes the complex tissue microstructure by differentiating compartment-specific T2 relaxation times. However, estimation methods are still limited by their sensitivity to the underlying noise. Moreover, estimating the model's parameters is challenging because the resulting inverse problem is ill-posed, requiring advanced numerical regularization techniques. As a result, the estimates from distinct regularization strategies are different. In this work, we aimed to investigate the variability and reproducibility of different techniques for estimating the transverse relaxation time of the intra- and extra-cellular space (T2IE) in gray (GM) and white matter (WM) tissue in a clinical setting, using a multi-site, multi-session, and multi-run T2 relaxometry dataset. To this end, we evaluated three different techniques for estimating the T2 spectra (two regularized non-negative least squares methods and a machine learning approach). Two independent analyses were performed to study the effect of using raw and denoised data. For both the GM and WM regions, and the raw and denoised data, our results suggest that the principal source of variance is the inter-subject variability, showing a higher coefficient of variation (CoV) than those estimated for the inter-site, inter-session, and inter-run, respectively. For all reconstruction methods studied, the CoV ranged between 0.32 and 1.64%. Interestingly, the inter-session variability was close to the inter-scanner variability with no statistical differences, suggesting that T2IE is a robust parameter that could be employed in multi-site neuroimaging studies. Furthermore, the three tested methods showed consistent results and similar intra-class correlation (ICC), with values superior to 0.7 for most regions. Results from raw data were slightly more reproducible than those from denoised data. The regularized non-negative least squares method based on the L-curve technique produced the best results, with ICC values ranging from 0.72 to 0.92

    Monitoring Carbon Ion Beams Transverse Position Detecting Charged Secondary Fragments: Results From Patient Treatment Performed at CNAO

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    Particle therapy in which deep seated tumours are treated using 12C ions (Carbon Ions RadioTherapy or CIRT) exploits the high conformity in the dose release, the high relative biological effectiveness and low oxygen enhancement ratio of such projectiles. The advantages of CIRT are driving a rapid increase in the number of centres that are trying to implement such technique. To fully profit from the ballistic precision achievable in delivering the dose to the target volume an online range verification system would be needed, but currently missing. The 12C ions beams range could only be monitored by looking at the secondary radiation emitted by the primary beam interaction with the patient tissues and no technical solution capable of the needed precision has been adopted in the clinical centres yet. The detection of charged secondary fragments, mainly protons, emitted by the patient is a promising approach, and is currently being explored in clinical trials at CNAO. Charged particles are easy to detect and can be back-tracked to the emission point with high efficiency in an almost background-free environment. These fragments are the product of projectiles fragmentation, and are hence mainly produced along the beam path inside the patient. This experimental signature can be used to monitor the beam position in the plane orthogonal to its flight direction, providing an online feedback to the beam transverse position monitor chambers used in the clinical centres. This information could be used to cross-check, validate and calibrate, whenever needed, the information provided by the ion chambers already implemented in most clinical centres as beam control detectors. In this paper we study the feasibility of such strategy in the clinical routine, analysing the data collected during the clinical trial performed at the CNAO facility on patients treated using 12C ions and monitored using the Dose Profiler (DP) detector developed within the INSIDE project. On the basis of the data collected monitoring three patients, the technique potential and limitations will be discussed

    Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

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    Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

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    BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years
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