Construcción del primer prototipo de radiómetro fotovoltaico sumergible de bajo costo

El Departamento Energía Solar de la Comisión Nacional de Energía Atómica viene realizando desarrollos en equipos de medición de radiación solar fotovoltaicos para uso terrestre y espacial desde 1999. En este contexto y con el fin de completar el espectro de los equipos desarrollados, se diseñó y fabricó un prototipo de radiómetro fotovoltaico sumergible apto para uso en distintos medios acuáticos. El desarrollo de este instrumento tiene aplicaciones en distintas áreas, por ejemplo, para la apicultura y la producción de algas. Se presentan los cálculos para el diseño, elaboración y caracterización del sensor de silicio así como el diseño del soporte con las características necesarias para ser sumergido en distintos ecosistemas. El prototipo desarrollado fue contrastado (dentro y fuera del agua) con un piranómetro Kipp & Zonen. Los resultados muestran un buen comportamiento del instrumento.The Solar Energy Department of the National Atomic Energy Commission has been making developments in photovoltaic equipment for solar radiation measurement for terrestrial and space uses since 1999. In this context and in order to complete the spectrum of developed equipment, a photovoltaic solar sensor of monocristaline silicon and the support for a submersible photovoltaic solarimeter suitable for use in different aquatic environments were designed and manufactured. This development is important, for example, for beekeeping and algae production. The manufacturing process of photovoltaic silicon sensors used at the instrument, its design according to the sensor signal due to attenuation when immersed and its size adaptation are presented. The prototype developed was contrasted (in and out of the water) with a Kipp & Zonen pyranometer. The results show that it complied with the specifications originally raised.Tema 4: Energía solar, conversión fotovoltaica.Facultad de Arquitectura y Urbanism

Construcción del primer prototipo de radiómetro fotovoltaico sumergible de bajo costo

El Departamento Energía Solar de la Comisión Nacional de Energía Atómica viene realizando desarrollos en equipos de medición de radiación solar fotovoltaicos para uso terrestre y espacial desde 1999. En este contexto y con el fin de completar el espectro de los equipos desarrollados, se diseñó y fabricó un prototipo de radiómetro fotovoltaico sumergible apto para uso en distintos medios acuáticos. El desarrollo de este instrumento tiene aplicaciones en distintas áreas, por ejemplo, para la apicultura y la producción de algas. Se presentan los cálculos para el diseño, elaboración y caracterización del sensor de silicio así como el diseño del soporte con las características necesarias para ser sumergido en distintos ecosistemas. El prototipo desarrollado fue contrastado (dentro y fuera del agua) con un piranómetro Kipp & Zonen. Los resultados muestran un buen comportamiento del instrumento.The Solar Energy Department of the National Atomic Energy Commission has been making developments in photovoltaic equipment for solar radiation measurement for terrestrial and space uses since 1999. In this context and in order to complete the spectrum of developed equipment, a photovoltaic solar sensor of monocristaline silicon and the support for a submersible photovoltaic solarimeter suitable for use in different aquatic environments were designed and manufactured. This development is important, for example, for beekeeping and algae production. The manufacturing process of photovoltaic silicon sensors used at the instrument, its design according to the sensor signal due to attenuation when immersed and its size adaptation are presented. The prototype developed was contrasted (in and out of the water) with a Kipp & Zonen pyranometer. The results show that it complied with the specifications originally raised.Tema 4: Energía solar, conversión fotovoltaica.Facultad de Arquitectura y Urbanism

Discovery and quantification of anaerobic nitrogen metabolisms among oxygenated tropical Cuban stony corals

© The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Babbin, A. R., Tamasi, T., Dumit, D., Weber, L., Rodríguez, M. V. I., Schwartz, S. L., Armenteros, M., Wankel, S. D., & Apprill, A. Discovery and quantification of anaerobic nitrogen metabolisms among oxygenated tropical Cuban stony corals. ISME Journal, (2020), doi:10.1038/s41396-020-00845-2.Coral reef health depends on an intricate relationship among the coral animal, photosynthetic algae, and a complex microbial community. The holobiont can impact the nutrient balance of their hosts amid an otherwise oligotrophic environment, including by cycling physiologically important nitrogen compounds. Here we use 15N-tracer experiments to produce the first simultaneous measurements of ammonium oxidation, nitrate reduction, and nitrous oxide (N2O) production among five iconic species of reef-building corals (Acropora palmata, Diploria labyrinthiformis, Orbicella faveolata, Porites astreoides, and Porites porites) in the highly protected Jardines de la Reina reefs of Cuba. Nitrate reduction is present in most species, but ammonium oxidation is low potentially due to photoinhibition and assimilatory competition. Coral-associated rates of N2O production indicate a widespread potential for denitrification, especially among D. labyrinthiformis, at rates of ~1 nmol cm−2 d−1. In contrast, A. palmata displays minimal active nitrogen metabolism. Enhanced rates of nitrate reduction and N2O production are observed coincident with dark net respiration periods. Genomes of bacterial cultures isolated from multiple coral species confirm that microorganisms with the ability to respire nitrate anaerobically to either dinitrogen gas or ammonium exist within the holobiont. This confirmation of anaerobic nitrogen metabolisms by coral-associated microorganisms sheds new light on coral and reef productivity.Research was conducted in the Gardens of the Queen, Cuba in accordance with the requirements of the Republic of Cuba, conducted under permit NV2370 and NV2568 issued by the Ministerio de Relaciones Exteriores. We gratefully acknowledge funding for this research by MIT Sea Grant award #2018-DOH-49-LEV, Simons Foundation award #622065, and MIT ESI seed funding to ARB, the MIT Montrym, Ferry, and mTerra Seed Grant Funds, and the generous contributions by Dr Bruce L. Heflinger

Intraoperative Quantification of MDS-UPDRS Tremor Measurements Using 3D Accelerometry:A Pilot Study

The most frequently used method for evaluating tremor in Parkinson’s disease (PD) is currently the internationally standardized Movement Disorder Society—Unified PD Rating Scale (MDS-UPDRS). However, the MDS-UPDRS is associated with limitations, such as its inherent subjectivity and reliance on experienced raters. Objective motor measurements using accelerometry may overcome the shortcomings of visually scored scales. Therefore, the current study focuses on translating the MDS-UPDRS tremor tests into an objective scoring method using 3D accelerometry. An algorithm to measure and classify tremor according to MDS-UPDRS criteria is proposed. For this study, 28 PD patients undergoing neurosurgical treatment and 26 healthy control subjects were included. Both groups underwent MDS-UPDRS tests to rate tremor severity, while accelerometric measurements were performed at the index fingers. All measurements were performed in an off-medication state. Quantitative measures were calculated from the 3D acceleration data, such as tremor amplitude and area-under-the-curve of power in the 4–6 Hz range. Agreement between MDS-UPDRS tremor scores and objective accelerometric scores was investigated. The trends were consistent with the logarithmic relationship between tremor amplitude and MDS-UPDRS score reported in previous studies. The accelerometric scores showed a substantial concordance (>69.6%) with the MDS-UPDRS ratings. However, accelerometric kinetic tremor measures poorly associated with the given MDS-UPDRS scores (R2 < 0.3), mainly due to the noise between 4 and 6 Hz found in the healthy controls. This study shows that MDS-UDPRS tremor tests can be translated to objective accelerometric measurements. However, discrepancies were found between accelerometric kinetic tremor measures and MDS-UDPRS ratings. This technology has the potential to reduce rater dependency of MDS-UPDRS measurements and allow more objective intraoperative monitoring of tremor

The Relevance of Intraoperative Clinical and Accelerometric Measurements for Thalamotomy Outcome

Thalamotomy alleviates medication-refractory tremors in patients with movement disorders such as Parkinson's Disease (PD), Essential tremor (ET), and Holmes tremor (HT). However, limited data are available on tremor intensity during different thalamotomy stages. Also, the predictive value of the intraoperative tremor status for treatment outcomes remains unclear. Therefore, we aimed to quantify tremor status during thalamotomy and postoperatively. Data were gathered between January 2020 and June 2023 during consecutive unilateral thalamotomy procedures in patients with PD ( n = 13), ET ( n = 8), and HT ( n = 3). MDS-UPDRS scores and tri-axial accelerometry data were obtained during rest, postural, and intention tremor tests. Measurements were performed intraoperatively (1) before lesioning-probe insertion, (2) directly after lesioning-probe insertion, (3) during coagulation, (4) directly after coagulation, and (5) 4-6 months post-surgery. Accelerometric data were recorded continuously during the coagulation process. Outcome measures included MDS-UPDRS tremor scores and accelerometric parameters (peak frequency, tremor amplitude, and area under the curve of power (AUCP)). Tremor intensity was assessed for the insertion effect (1-2), during coagulation (3), post-coagulation effect (1-4), and postoperative effect (1-5). Following insertion and coagulation, tremor intensity improved significantly compared to baseline ( p &lt; 0.001). The insertion effect clearly correlated with the postoperative effect ( ρ = 0.863, p &lt; 0.001). Both tremor amplitude and AUCP declined gradually during coagulation. Peak frequency did not change significantly intraoperatively. In conclusion, the study data show that both the intraoperative insertion effect and the post-coagulation effect are good predictors for thalamotomy outcomes. </p

Fabricación de solarímetros de bajo costo en la Argentina: algunas propuestas teóricas y primeras experiencias

Se iniciaron actividades de diseño teórico y desarrollo experimental de sensores de radiación solar de bajo costo basados en celdas fotovoltaicas de silicio cristalino. En particular, se analizaron las principales limitaciones, asociadas a la respuesta espectral de las celdas, que atentan contra la precisión de la medición en este tipo de sensores. Se estudiaron y optimizaron multicapas dieléctricas sencillas para ser depositadas sobre el fotodiodo, en reemplazo del tratamiento antirreflectante convencional, de manera de lograr una respuesta espectral lo más plana posible en el rango de longitudes de onda de 350nm a 1000nm. Se realizaron las primeras experiencias de fabricación de piranómetros con celdas solares elaboradas en la CNEA cubiertas con un vidrio esmerilado como difusor frontal.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES

Assessment of intracranial vessels in association with carotid atherosclerosis and brain vascular lesions in rheumatoid arthritis

BACKGROUND: Stroke has been associated with rheumatoid arthritis (RA). We assessed patients with RA and healthy control subjects by transcranial Doppler (TCD), carotid ultrasonography and brain magnetic resonance imaging (MRI). METHODS: Altogether, 41 female patients with RA undergoing methotrexate (MTX) or biologic treatment and 60 age-matched control subjects underwent TCD assessment of the middle cerebral artery (MCA) and basilar artery. Pulsatility index (PI), resistivity (resistance) index (RI) and circulatory reserve capacity (CRC) were determined at rest (r) and after apnoea (a) and hyperventilation (h). The presence of carotid plaques and carotid intima-media thickness (cIMT) were also determined. Intracerebral vascular lesions were investigated by brain MRI. RESULTS: MCA PI and RI values at rest and after apnoea were significantly increased in the total and MTX-treated RA populations vs control subjects. MCA CRC was also impaired, and basilar artery PI was higher in RA. More patients with RA had carotid plaques and increased cIMT. Linear regression analysis revealed that left PI(r) and RI(r) correlated with disease duration and that left PI(r), RI(r), PI(a), PI(h) and basilar PI correlated with disease activity. Right CRC inversely correlated with 28-joint Disease Activity Score. Disease activity was an independent determinant of left PI(a) and right CRC. Compared with long-term MTX treatment alone, the use of biologics in combination with MTX was associated with less impaired cerebral circulation. Impaired cerebral circulation was also associated with measures of carotid atherosclerosis. CONCLUSIONS: To our knowledge, this is the first study to show increased distal MCA and basilar artery occlusion in RA as determined by TCD. Patients with RA also had CRC defects. We also confirmed increased carotid plaque formation and increased cIMT. Biologics may beneficially influence some parameters in the intracranial vessels

Elaboración y caracterización de celdas y paneles solares de silicio cristalino para su ensayo en el satélite SAC-A

Se describen los procesos utilizados para la elaboración de un conjunto de celdas y paneles fotovoltaicos que serán incluidos en el satélite argentino SAC-A, para su ensayo en ambiente espacial. Seis de las celdas serán utilizadas como sensores para la determinación de la posición angular del satélite. Los procesos mencionados incluyen la elaboración de celdas, su interconexión y el armado de los paneles. Las celdas solares fueron caracterizadas eléctricamente antes y después de su integración en los paneles. Se presentan las primeras experiencias de daño producido por bombardeo con protones y neutrones en laboratorio.Tema: Conversión Fotovoltaica.Asociación Argentina de Energía Sola

Ligand substitution reactions of a phenolic quinolyl hydrazone; oxidovanadium (IV) complexes

<p>Abstract</p> <p>Background</p> <p>Quinoline ring has therapeutic and biological activities. Quinolyl hydrazones constitute a class of excellent chelating agents. Recently, the physiological and biological activities of quinolyl hydrazones arise from their tendency to form metal chelates with transition metal ions. In this context, we have aimed to study the competency effect of a phenolic quinolyl hydrazone (H₂L; primary ligand) with some auxiliary ligands (Tmen, Phen or Oxine; secondary ligands) towards oxidovanadium (IV) ions.</p> <p>Results</p> <p>Mono- and binuclear oxidovanadium (IV) - complexes were obtained from the reaction of a phenolic quinolyl hydrazone with oxidovanadium (IV)- ion in absence and presence of N,N,N',N'- tetramethylethylenediamine (Tmen), 1,10-phenanthroline (Phen) or 8-hydroxyquinoline (Oxine). The phenolic quinolyl hydrazone ligand behaves as monobasic bidentate (NO- donor with O- bridging). All the obtained complexes have the preferable octahedral geometry except the oxinato complex (<b>2</b>) which has a square pyramid geometry with no axial interaction; the only homoleptic complex in this study.</p> <p>Conclusion</p> <p>The ligand exchange (substitution/replacement) reactions reflect the strong competency power of the auxiliary aromatic ligands (Phen/Oxine) compared to the phenolic quinolyl hydrazone (H₂L) towards oxidovanadium (IV) ion; (complexes <b>2 </b>and <b>3</b>). By contrast, in case of the more flexible aliphatic competitor (Tmen), an adduct was obtained (<b>4</b>). The obtained complexes reflect the strength of the ligand field towards the oxidovanadium (IV)- ion; Oxine or Phen >> phenolic hydrazone (H₂L) > Tmen.</p