Determination of Cu in blood: Via direct analysis of dried blood spots using high-resolution continuum source graphite furnace atomic absorption spectrometry

The performance of state-of-the-art high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS) instrumentation and four novel devices to produce dried blood spots of perfectly defined volumes is evaluated with the aim of developing a simple, direct method for the determination of Cu in blood samples. In all cases, it is feasible to obtain accurate quantitative information using any of the four devices tested (Mitra, HemaXis DB10, Capitainer qDBS and HemaPEN) via simple external calibration with aqueous standards. One of the main differences in the performance of such devices is related to the blanks obtained, such that HemaXis DB10 and HemaPEN are preferred when abnormally low Cu levels (500 µg L-1 or lower), associated with some diseases, need to be determined. The results prove that accurate values with RSD values below 10% can be achieved for these devices even for such Cu levels, while for Capitainer qDBS and, to a higher extent, for Mitra, blank variations will ultimately increase the uncertainty. It is important to stress that analysis of four real samples using both venipuncture and all the DBS specimens showed a very good agreement. Thus, the approach proposed could be readily applied, such that patients with disorders requiring Cu control can prepare their own samples and submit them via postal mail to labs for HR CS GFAAS direct and fast analysis. © The Royal Society of Chemistry

Diagnostic ability of multifocal electroretinogram in early multiple sclerosis using a new signal analysis method

Purpose To determine if a novel analysis method will increase the diagnostic value of the multifocal electroretinogram (mfERG) in diagnosing early-stage multiple sclerosis (MS). Methods We studied the mfERG signals of OD (Oculus Dexter) eyes of fifteen patients diagnosed with early-stage MS (in all cases < 12 months) and without a history of optic neuritis (ON) (F: M = 11:4), and those of six controls (F:M = 3:3). We obtained values of amplitude and latency of N1 and P1 waves, and a method to assess normalized root-mean-square error (FNRMSE) between model signals and mfERG recordings was used. Responses of each eye were analysed at a global level, and by rings, quadrants and hemispheres. AUC (area under the ROC curve) is used as discriminant factor. Results The standard method of analysis obtains further discrimination between controls and MS in ring R3 (AUC = 0.82), analysing N1 waves amplitudes. In all of the retina analysis regions, FNRMSE value shows a greater discriminating power than the standard method. The highest AUC value (AUC = 0.91) was in the superior temporal quadrant. Conclusion By analysing mfERG recordings and contrasting them with those of healthy controls it is possible to detect early-stage MS in patients without a previous history of ON

Mortars Modified with Geothermal Nanosilica Waste: Effect on the Electrochemical Properties of Embedded Steel Rods

Nowadays, it is a common practice the incorporation of industrial wastes as alternative materials to replace ordinary Portland cement in the concrete manufacture. This technological implementation has as main objectives, the enhancement of concretes properties as well as mitigation of durability problem related to the corrosion phenomena; in order to increase the service life of reinforced concrete structures. Therefore, in this research was studied the electrochemical properties of black steel embedded in mortars. Mortars were fabricated using as a partial substitute of cement (0, 10, 20 and 30 wt. %) a geothermal nanosilica waste composed of amorphous nanosilica of ~20ηm and chlorides (0 and 0.4 wt. %). Mortars were subjected to a cure at 20°C (80% of relative humidity) and 60ºC (100% of relative humidity). The corrosion behaviour was periodically monitorized up to 65 days using electrochemical techniques of corrosion potential (Ecorr) and corrosion current density (icorr). Values of current density (icorr) were obtained by linear polarization resistance (LPR) technique applying Stern-Geary relation to Rp values. Electrochemical results were validated by comparing with gravimetric losses. The porosity, pH and loss of the evaporated water were also evaluated in mortars. Results obtained showed that the integrity of reinforcement rods was affected with the increase of GNW at high temperatures as well as the total chlorides content in mortars

Performance of grid-tied PV facilities based on real data in Spain: Central inverter versus string system

Two complete years of operation of two grid-tied PV facilities is presented. Energetic and economic performance of both installations has been compared. Located in the same place, the installation of these facilities followed the same construction criteria – PV panels, panel support system and wiring – and the facilities are exposed to the same atmospheric temperature and solar radiation. They differ with regard to their inverter topology used: one facility uses a central inverter and the other a string inverter configuration. The performance of the facilities has been determined using a procedure based on a small number of easily obtained parameters and the knowledge of the analyzed system and its operation mode. Electrical losses have been calculated for both systems and a complete comparison between them has been carried out. The results have shown better performance for distributed system in economic and energetic terms.Spanish Government (Grant ENE2011-27511) and the Department of Culture and Education of the Regional Government of Castilla y León, Spain (Grant BU358A12-2)

A new diffuse luminous efficacy model for daylight availability in Burgos, Spain

The determination of optimal illumination conditions in buildings is of great interest both for reducing energy consumption and for exploiting solar resources with greater efficiency and sustainability. The most commonplace method of estimating daylight is the luminous efficacy approach, using the more widely measured solar irradiance. In this present study, a new model of diffuse luminous efficacy over a horizontal surface is proposed. A comparative study of twenty-two classic models is presented, to obtain diffuse illuminance, using both, the original mathematical models and the adapted models with local coefficients, in order to determine the most suitable models for Burgos, a city located in north-western Spain. With this purpose in mind, twelve models are selected for all sky conditions, five models for modelling clear sky, two for partly cloudy sky, and three for overcast sky. These twenty-two models are then compared with the new model both for all sky conditions and for particular sky conditions (clear, partly cloudy, and overcast). The behaviour of the new model showed greater accuracy than most of the classic models under analysis. Hence, the advantage of the diffuse luminous efficacy model that can be applied both to all sky and to particular sky conditions.Spanish Government (Ministerio de Economía y Competitividad) (ENE2014-54601-R). David González Peña would also like to thank the Junta de Castilla-León for economic support (PIRTU Program, ORDEN EDU/310/2015)

Performance analysis of PV plants: Optimization for improving profitability

A study is conducted of real PV production from two 100 kWp grid-connected installations located in the same area, both of which experience the same fluctuations in temperature and radiation. Data sets on production were collected over an entire year and both installations were compared under various levels of radiation. The installations were assembled with mono-Si panels, mounted on the same support system, and the power supply was equal for the inverter and the measurement system; the same parameters were also employed for the wiring, and electrical losses were calculated in both cases. The results, in economic terms, highlight the importance of properly selecting the system components and the design parameters for maximum profitabilit

Understanding the complex geomorphology of a deep sea area affected by continental tectonic indentation: the case of the Gulf of Vera (Western Mediterranean)

We present a multidisciplinary study of morphology, stratigraphy, sedimentology, tectonic structure, and physical oceanography to report that the complex geomorphology of the Palomares continental margin and adjacent Algerian abyssal plain (i.e., Gulf of Vera, Western Mediterranean), is the result of the sedimentary response to the Aguilas Arc continental tectonic indentation in the Eurasian–Africa plate collision. The inden tation is imprinted on the basement of the margin with elongated metamorphic antiforms that are pierced by igneous bodies, and synforms that accommodate the deformation and create a complex physiography. The basement is partially covered by Upper Miocene deposits sealed by the regional Messinian Erosive Surface characterized by palaeocanyons that carve the modern margin. These deposits and outcropping basement highs are then covered and shaped by Plio-Quaternary contourites formed under the action of the Light Intermediate and Dense Deep Mediterranean bottom currents. Even though bottom currents are responsible for the primary sedimentation that shapes the margin, 97% of this region's seafloor is affected by mass-movements that modified contourite sediments by eroding, deforming, faulting, sliding, and depositing sediments. Mass-movement processes have resulted in the formation of recurrent mass-flow deposits, an enlargement of the submarine canyons and gully incisions, and basin-scale gravitational slides spreading above the Messinian Salinity Crisis salt layer. The Polopo, Aguilas and Gata slides are characterized by an extensional upslope domain that shapes the continental margin, and by a downslope contractional domain that shapes the abyssal plain with diapirs piercing (hemi)pelagites/sheet-like turbidites creating a seafloor dotted by numerous crests. The mass movements were mostly triggered by the interplay of the continental tectonic indentation of the Aguilas Arc with sedimentological factors over time. The indentation, which involves the progressively southeastward tectonic tilting of the whole land-sea region, likely generated a quasi-continuous oversteepening of the entire margin, thus reducing the stability of the contourites. In addition, tectonic tilting and subsidence of the abyssal plain favoured the flow of the underlying Messinian Salinity Crisis salt layer, contributing to the gravitational instability of the overlying sediments over large areas of the margin and abyssal plain