DSpace Angular :: Browsing by Author "Agosin, Eduardo"

Browsing by Author "Agosin, Eduardo"

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A multipurpose portable instrument for determining ripeness in wine grapes using NIR spectroscopy
(IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2008) Larrain, Manuel; Guesalaga, Andres R.; Agosin, Eduardo
This paper describes the development of a noninvasive instrument that is designed to measure three parameters of ripeness in wine grapes, i.e., sugar (Brix), pH, and anthocyanin concentration. The instrument is based on near-infrared spectroscopy, and it comes in contact with the berry in the cluster without altering its ripening process. A thorough description of the calibration process for the instrument is done for the different grape varieties, e.g., Cabernet Sauvignon, Carmenere, Merlot, Pinot Noir, and Chardonnay. Samples from vineyards located in the Maipo Valley (Chile) taken during the 2003 season were processed to develop calibration models using partial least squares techniques. The models were validated in terms of root mean square error of validation and R-2 indices. The results show the great potential of this technique regarding Brix and pH measurements. For the anthocyanin concentration measurements, the results are promising but require an accurate procedure to obtain reference values for model calibration. The instrument can be useful for sampling strategies that look for optimum harvest schedules according to grape maturity in terms of not only sugar content but also pH and anthocyanin concentration.
A portable non-destructive volume meter for wine grape clusters
(2006) Iraguen, Vicente; Guesalaga, Andres; Agosin, Eduardo
A portable non-destructive instrument has been developed for the measurement of grape cluster volume using air displacement techniques. The design satisfies the producer's need to determine cluster growth curves in order to estimate the optimum time to start the harvest. Several ways of processing data were evaluated, including different models and parameters related to thermodynamic, mechanical and electronic aspects. Using an empirical calibration technique, the device performs with an acceptable accuracy for field measurements, with errors below 20 cm(3) and R-2 higher than 0.92. It is intended for sample volumes between 80 cm(3) and 500 cm(3). The instrument was intensively tested in three vineyards and for different atmospheric pressures, achieving good results and validating its use for harvest volume estimation. The instrument can be adapted so that it can be used for other types of fruit and vegetables.
Characterization of Vitis vinifera L. cv. Carmenere grape and wine proanthocyanidins
(AMER CHEMICAL SOC, 2007) Fernandez, Katherina; Kennedy, James A.; Agosin, Eduardo
A formal compositional study of the proanthocyanidins of Vitis vinifera L. cv. Carmenere was conducted in this work. We first characterized the polymeric proanthocyanidins of Carmenere skins, seeds, and wines. In addition, the wine astringency was analyzed and compared with Cabernet Sauvignon. Although Carmenere wines had a higher proanthocyanidin concentration and mean degree of polymerization than Cabernet Sauvignon wines, the former wines were perceived as less astringent. The low seed/skin proportion in Carmenere wines as compared to other varieties, as evidenced by the reduced number of seeds per berry and the higher amount of epigallocatechin subunits of Carmenere wine proanthocyanidins, could explain this apparent paradox.
Comparative study of wine tannin classification using Fourier transform mid-infrared spectrometry and sensory analysis
(SOC APPLIED SPECTROSCOPY, 2007) Fernandez, Katherina; Labarca, Ximena; Bordeu, Edmundo; Guesalaga, Andres; Agosin, Eduardo
Wine tannins are fundamental to the determination of wine quality. However, the chemical and sensorial analysis of these compounds is not straightforward and a simple and rapid technique is necessary. We analyzed the mid-infrared spectra of white, red, and model wines spiked with known amounts of skin or seed tannins, collected using Fourier transform mid-infrared (FT-MIR) transmission spectroscopy (400-4000 cm(-1)). The spectral data were classified according to their tannin source, skin or seed, and tannin concentration by means of discriminant analysis (DA) and soft independent modeling of class analogy (SIMCA) to obtain a probabilistic classification. Wines were also classified sensorially by a trained panel and compared with FT-MIR. SIMCA models gave the most accurate classification (over 97%) and prediction (over 60%) among the wine samples. The prediction was increased (over 73%) using the leave-one-out cross-validation technique. Sensory classification of the wines was less accurate than that obtained with FT-MIR and SINICA. Overall, these results show the potential of FT-MIR spectroscopy, in combination with adequate statistical tools, to discriminate wines with different tannin levels.
Coupling kinetic expressions and metabolic networks for predicting wine Fermentations
(WILEY, 2007) Pizarro, Francisco; Varela, Cristian; Martabit, Cecilia; Bruno, Claudio; Prez Correa, J. Ricardo; Agosin, Eduardo
Problematic fermentations are commonplace and cause wine industry producers substantial economic losses through wasted tank capacity and low value final products. Being able to predict such fermentations would enable enologists to take preventive actions. In this study we modeled sugar uptake kinetics and coupled them to a previously developed stoichiometric model, which describes the anaerobic metabolism of Saccharomyces cerevisiae. The resulting model was used to predict normal and slow fermentations under winemaking conditions. The effects of fermentation temperature and initial nitrogen concentration were modeled through an efficiency factor incorporated into the sugar uptake expressions. The model required few initial parameters to successfully reproduce glucose, fructose, and ethanol profiles of laboratory and industrial fermentations. Glycerol and biomass profiles were successfully predicted in nitrogen rich cultures. The time normal or slow wine fermentations needed to complete the process was predicted accurately, at different temperatures. Simulations with a model representing a genetically modified yeast fermentation, reproduced qualitatively well literature results regarding the formation of minor compounds involved in wine complexity and aroma. Therefore, the model also proves useful to explore the effects of genetic modifications on fermentation profiles.
Differential synthesis of fermentative aroma compounds of two related commercial wine yeast strains
(ELSEVIER SCI LTD, 2009) Molina, Ana M.; Guadalupe, Victor; Varela, Cristian; Swiegers, Jan H.; Pretorius, Isak S.; Agosin, Eduardo
The specific impact of the yeast strain on the wine flavour and aroma has not been well characterised yet because this effect is usually combined with other variables during the winemaking. In this study, the contribution to wine flavour of two Saccharomyces cerevisiae strains widely used in wine production, VIN13 and EC1118, was evaluated after fermentation at 15 degrees C. Chemical defined grape juice media fermented with the EC1118 strain showed higher solvent, fatty and pineapple aroma attributes, while that fermented with the VIN13 strain exhibited higher banana, fruity, yeasty and green attributes. Sensorial and chemical analyses evidenced that the production of flavour-active compounds is significantly affected by the yeast strain, as well as by the temperature of fermentation, as shown by comparing the former data with those from fermentations carried out at 28 degrees C under identical culture conditions. (C) 2009 Elsevier Ltd. All rights reserved.
Effects of Temperature and Time on Polyphenolic Content and Antioxidant Activity in the Pressurized Hot Water Extraction of Deodorized Thyme (Thymus vulgaris)
(AMER CHEMICAL SOC, 2012) Vergara Salinas, Jose R.; Perez Jimenez, Jara; Lluis Torres, Josep; Agosin, Eduardo; Perez Correa, Jose R.
The effects of temperature (50-200 degrees C) and contact time (5-30 min) on the pressurized hot water extraction of deodorized thyme were explored for antioxidant activity, polyphenol profiles, and total antioxidants. Six not previously reported polyphenolic compounds were identified in thyme. An inverse correlation was found between the antioxidant activity and total antioxidants with the amount and diversity of polyphenols. The highest total extract yield and antioxidant activity were obtained at 200 degrees C, although maximum polyphenol extraction yields of hydroxycinnamic acids, flavones, flavonols/flavanones, and total polyphenols were detected at 100 degrees C and 5 min. Higher temperatures and longer exposure times reduced extract polyphenol diversity. Dihydroxyphenyllactic acid was the only phenolic compound for which extraction yield increased with temperature, probably as a product of the thermal degradation of rosmarinic acid. Consequently, for extracting phenolics from thyme, 100 degrees C and 5 min would be appropriate operating conditions, whereas antioxidant active nonphenolic compounds were favored at higher temperatures and exposure times.
Exploring the applicability of MIR spectroscopy to detect early indications of wine fermentation problems
(ELSEVIER SCI LTD, 2008) Urtubia, Alejandra; Perez correa, J. Ricardo; Pizarro, Francisco; Agosin, Eduardo
In this study we explore the applicability of MIR technology to detect early indications of wine fermentation problems. An oenologist could improve the chances of a vinification process finishing optimally if anomalies are detected early. A comparative analysis of three fermentations with artificial musts was performed; one of normal behaviour, one subject to a temperature gradient, and the third deficient in assimilable nitrogen. We tracked each fermentation through changes in spectra in addition to changes in must composition. It was easier to detect anomalous behaviour by monitoring wine metabolite concentrations than through direct spectra analysis, nevertheless, calibrations needed to be derived from fermenting must samples and so cost more. All measured compounds (glucose, fructose, ethanol, glycerol, succinic and acetic acids) exhibited behavioural changes at 30 h of fermentation in nitrogen deficient musts. Temperature deviations were reflected in the anomalous behaviour of ethanol, glycerol, succinic acid and acetic acid. (c) 2007 Elsevier Ltd. All rights reserved.
Furan Occurrence in Starchy Food Model Systems Processed at High Temperatures: Effect of Ascorbic Acid and Heating Conditions
(AMER CHEMICAL SOC, 2012) Mariotti, Maria; Granby, Kit; Fromberg, Arvid; Risum, Jorgen; Agosin, Eduardo; Pedreschi, Franco
Furan, a potential carcinogen, has been detected in highly consumed starchy foods, such as bread and snacks; however, research on furan generation in these food matrixes has not been undertaken, thus far. The present study explored the effect of ascorbic acid addition and cooking methods (frying and baking) over furan occurrence and its relation with the non-enzymatic browning in a wheat flour starchy food model system. Results showed that furan generation significantly increased in the presence of ascorbic acid after 7 mm of heating (p < 0.05). The strongest effect was observed for baked products. Additionally, the furan content in fried products increased with the increase of the oil uptake levels. As for Mallard reactions, in general, the furan level in all samples linearly correlated with their degree of non-enzymatic browning, represented by L* and a* color parameters (e.g., wheat flour baked samples showed a R-2 of 0.88 and 0.87 for L* and a*, respectively), when the sample moisture content decreased during heating.
GAS CHROMATOGRAPHY COUPLED WITH MASS SPECTROMETRY DETECTION FOR THE VOLATILE PROFILING OF VITIS VINIFERA CV. CARMENERE WINES
(2010) Maria Dominguez, Ana; Agosin, Eduardo
The volatile metabolome of Vitis vinifera C.V. Carmenere wines, a unique Chilean winegrape variety, was characterized in this work. After solvent extraction with dichloromethane (LLE) or head space solid phase microextraction (HS-SPME), the resulting volatile compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). Specific methods were carried out too for the determination of methoxypyrazines and thiols. Almost 150 compounds corresponding to aliphatic and aromatic alcohols, organic acids, acetate and ethyl esters, lactones, terpenes, norisoprenoids, pyrazines, thiols and phenolic compounds were found in these wines. Both extraction techniques were complementary; HS-SPME allowed to identify several important compounds that were not detected by liquid-liquid solvent extraction, in particular b-damascenone, nerol idol, citronellol, linalool, ethyl 2-methyl-butyrate and geranyl acetone. Several varietal volatile compounds with significant odorant properties were also identified: 3-mercaptohexyl acetate (3MHA), 3-mercaptohexan-1-ol (3MH), benzenemethanethiol (BM), 2-furanmethanethiol (2FM); and 2-isobutyl-3-methoxypyrazine (IBMP) while 2-isopropyl-3-methoxypyrazine (IPMP) and 4-mercapto-4-methylpentan-2-one (4MMP) were not detected. Twenty two of these compounds, including b-damascenone, several thiols, ethyl octanoate, 2-phenylethanol, and 2-isobutyl-3-methoxypyrazine, showed significant odor activities values (OAV), and were clearly related with the cooked fruits, berries-like and herbaceous notes characteristic of Carmenere wines. Olfactometric techniques are underway to validate the sensory impact of these compounds.
Growth temperature exerts differential physiological and transcriptional responses in laboratory and wine strains of Saccharomyces cerevisiae
(AMER SOC MICROBIOLOGY, 2008) Pizarro, Francisco J.; Jewett, Michael C.; Nielsen, Jens; Agosin, Eduardo
Laboratory strains of Saccharomyces cerevisiae have been widely used as a model for studying eukaryotic cells and mapping the molecular mechanisms of many different human diseases. Industrial wine yeasts, on the other hand, have been selected on the basis of their adaptation to stringent environmental conditions and the organoleptic properties that they confer to wine. Here, we used a two-factor design to study the responses of a standard laboratory strain, CEN.PK113-7D, and an industrial wine yeast strain, EC1118, to growth temperatures of 15 degrees C and 30 degrees C in nitrogen-limited, anaerobic, steady-state chemostat cultures. Physiological characterization revealed that the growth temperature strongly impacted the biomass yield of both strains. Moreover, we found that the wine yeast was better adapted to mobilizing resources for biomass production and that the laboratory yeast exhibited higher fermentation rates. To elucidate mechanistic differences controlling the growth temperature response and underlying adaptive mechanisms between the strains, DNA microarrays and targeted metabolome analysis were used. We identified 1,007 temperature-dependent genes and 473 strain-dependent genes. The transcriptional response was used to identify highly correlated gene expression subnetworks within yeast metabolism. We showed that temperature differences most strongly affect nitrogen metabolism and the heat shock response. A lack of stress response element-mediated gene induction, coupled with reduced trehalose levels, indicated that there was a decreased general stress response at 15 degrees C compared to that at 30 degrees C. Differential responses among strains were centered on sugar uptake, nitrogen metabolism, and expression of genes related to organoleptic properties. Our study provides global insight into how growth temperature affects differential physiological and transcriptional responses in laboratory and wine strains of S. cerevisiae.
Heterologous production of the epoxycarotenoid violaxanthin in Saccharomyces cerevisiae
(2020) Cataldo, Vicente F.; Arenas, Natalia; Salgado, Valeria; Camilo, Conrado; Ibanez, Francisco; Agosin, Eduardo
Microbial production of carotenoids has mainly focused towards a few products, such as beta-carotene, lycopene and astaxanthin. However, other less explored carotenoids, like violaxanthin, have also shown unique properties and promissory applications. Violaxanthin is a plant-derived epoxidated carotenoid with strong antioxidant activity and a key precursor of valuable compounds, such as fucoxanthin and beta-damascenone. In this study, we report for the first time the heterologous production of epoxycarotenoids in yeast. We engineered the yeast Saccharomyces cerevisiae following multi-level strategies for the efficient accumulation of violaxanthin. Starting from a beta-carotenogenic yeast strain, we first evaluated the performance of several beta-carotene hydroxylases (CrtZ), and zeaxanthin epoxidases (ZEP) from different species, together with their respective N-terminal truncated variants. The combined expression of CrtZ from Pantoea ananatis and truncated ZEP of Haematococcus lacustris showed the best performance and led to a yield of 1.6 mg/g(DCW) of violaxanthin. Further improvement of the epoxidase activity was achieved by promoting the transfer of reducing equivalents to ZEP by expressing several redox partner systems. The co-expression of the plant truncated ferredoxin-3, and truncated root ferredoxin oxidoreductase-1 resulted in a 2.2-fold increase in violaxanthin yield (3.2 mg/g(DCW)). Finally, increasing gene copy number of carotenogenic genes enabled reaching a final production of 7.3 mg/g(DCW) in shake flask cultures and batch bioreactors, which is the highest yield of microbially produced violaxanthin reported to date.
Influence of wine fermentation temperature on the synthesis of yeast-derived volatile aroma compounds
(2007) Molina, Ana M.; Swiegers, Jan H.; Varela, Cristian; Pretorius, Isak S.; Agosin, Eduardo
The yeast Saccharomyces cerevisiae synthesises a variety of volatile aroma compounds during wine fermentation. In this study, the influence of fermentation temperature on (1) the production of yeast-derived aroma compounds and ( 2) the expression of genes involved in aroma compounds' metabolism (ADH1, PDC1, BAT1, BAT2, LEU2, ILV2, ATF1, ATF2, EHT1 and IAH1) was assessed, during the fermentation of a defined must at 15 and 28 C. Higher concentrations of compounds related to fresh and fruity aromas were found at 15 C, while higher concentrations of flowery related aroma compounds were found at 28 C. The formation rates of volatile aroma compounds varied according to growth stage. In addition, linear correlations between the increases in concentration of higher alcohol and their corresponding acetates were obtained. Genes presented different expression profiles at both temperatures, except ILV2, and those involved in common pathways were co-expressed (ADH1, PDC1 and BAT2; and ATF1, EHT1 and IAH1). These results demonstrate that the fermentation temperature plays an important role in the wine final aroma profile, and is therefore an important control parameter to fine-tune wine quality during winemaking.
Metabolic behavior for a mutant Oenococcus oeni strain with high resistance to ethanol to survive under oenological multi-stress conditions
(2023) Contreras, Angela; Diaz, Gabriela; Mendoza, Sebastian N.; Canto, Mauricio; Agosin, Eduardo
Malolactic fermentation (MLF) positively influences the quality of the wine, and it occurs as a result of a lactic acid bacteria's metabolism, mainly of the Oenococcus oeni species. However, delays and halting of MLF are frequent problems in the wine industry. This is mainly because O. oeni's development is inhibited by different kinds of stress. Even though the sequencing of the genome of the PSU-1 strain of O. oeni, as well as other strains, has made it possible to identify genes involved in the resistance to some types of stress, all of the factors that could be involved are still unknown. With the aim of contributing to this knowledge, the random mutagenesis technique was used in this study as a strategy for genetic improvement of strains of the O. oeni species. The technique proved to be capable of generating a different and improved strain when compared to the PSU-1 strain (the parent from which it descends). Then, we evaluated the metabolic behavior of both strains in three different wines. We used synthetic MaxOeno wine (pH 3.5; 15% v/v ethanol), red wine (Cabernet Sauvignon), and white wine (Chardonnay). Furthermore, we compared the transcriptome of both strains, grown in MaxOeno synthetic wine. The specific growth rate of the E1 strain was on average 39% higher in comparison to the PSU-1 strain. Interestingly, E1 strain showed an overexpression of the OEOE_1794 gene, which encodes a UspA-like protein, which has been described as promoting growth. We observed that the E1 strain was able to convert, on average, 34% more malic acid into lactate than the PSU-1 strain, regardless of the wine being used. On the other hand, the E1 strain showed a flux rate of fructose-6-phosphate production that was 86% higher than the mannitol production rate, and the internal flux rates increase in the direction of pyruvate production. This coincides with the higher number of OEOE_1708 gene transcripts observed in the E1 strain grown in MaxOeno. This gene encodes for an enzyme fructokinase (EC 2.7.1.4) involved in the transformation of fructose to fructose-6-phosphate.
Methoxypyrazines in grapes and wines of Vitis vinifera cv. Carmenere
(2007) Belancic, Andrea; Agosin, Eduardo
Vitis vinifera cv. Carmenere, a member of the Cabernet family, was recently rediscovered in Chile where it had been misidentified as Merlot. The Carmenere variety produces complex wines, marked with herbaceous and '' green '' aromas. Results indicate that methoxypyrazines are present in high concentrations in this variety, probably responsible for the strong vegetative character found in Carmenere wines. Wines from Carmenere grapes had high 3-isobutyl-2-methoxypyrazine (IBMP) concentrations (5.0 to 44.4 ng/L), much higher than most Cabernet Sauvignon wines. The genotype dramatically affected the methoxypyrazine content of Carmenere wines, with some clones containing three-fold more than others. Climatic conditions, rather than maturity or terroir, had a critical effect upon IBMP concentration in grapes. 3-Isopropyl-2-methoxypyrazine evolved differently during grape maturation and was less influenced by harvesting year.
Modeling temperature gradients in wine fermentation tanks
(ELSEVIER SCI LTD, 2010) Zenteno, M. Isabel; Perez Correa, J. Ricardo; Gelmi, Claudio A.; Agosin, Eduardo
Extreme temperatures are common in large wine fermentation tanks. If not controlled properly, they can lead to problematic fermentations. Thus, efficient cooling and automatic control systems must be designed. However, it is rather difficult to design and implement effective cooling and control systems without adequate models able to reproduce the complex dynamic behavior observed in large fermentors. Therefore, we developed a compartmental dynamic mass-and-energy-balance model able to simulate temperature and concentration gradients in large wine fermentation tanks. This paper presents the model, along with all its parameters. It discusses simulations of temperature, alcohol content, density, biomass, and sugar concentrations. Finally, it presents a sensitivity analysis of the must temperature dynamics. The model reproduced reasonably well the values of the observed variables, including the most critical one: must temperature (with an absolute mean error of 1.4 degrees C). After proper calibration, it can be used to design control strategies for cooling in large wine fermentation tanks. Our research efforts will be directed in designing such control strategies. (C) 2010 Elsevier Ltd. All rights reserved.
Parameter estimation in metabolic flux balance models for batch fermentation - formulation & solution using Differential Variational Inequalities (DVIs)
(SPRINGER, 2006) Raghunathan, Arvind U.; Ricardo Perez Correa, J.; Agosin, Eduardo; Biegler, Lorenz T.
Recent years have witnessed a surge in research in cellular biology. There has been particular interest in the interaction between cellular metabolism and its environment. In this work we present a framework for fitting fermentation models that include this interaction. Differential equations describe the evolution of extracellular metabolites, while a Linear Program (LP) models cell metabolism, and piecewise smooth functions model the links between cell metabolism and its environment. We show that the fermentation dynamics can be described using Differential Variational Inequalities (DVIs). Discretization of the system and reformulation of the VIs using optimality conditions converts the DVI to a Mathematical Program with Complementarity Constraints (MPCC). We briefly describe an interior point algorithm for solving MPCCs. Encouraging numerical results are presented in estimating model parameters to fit model prediction and data obtained from fermentation, using cultures of Saccharomyces cerevisiae reported in the literature.
Quantitative analysis of red wine tannins using Fourier-transform mid-infrared spectrometry
(AMER CHEMICAL SOC, 2007) Fernandez, Katherina; Agosin, Eduardo
Tannin content and composition are critical quality components of red wines. No spectroscopic method assessing these phenols in wine has been described so far. We report here a new method using Fourier transform mid-infrared (FT-MIR) spectroscopy and chemometric techniques for the quantitative analysis of red wine tannins. Calibration models were developed using protein precipitation and phloroglucinolysis as analytical reference methods. After spectra preprocessing, six different predictive partial least-squares (PLS) models were evaluated, including the use of interval selection procedures such as iPLS and CSMWPLS. PLS regression with full-range (650-4000 cm(-1)), second derivative of the spectra and phloroglucinolysis as the reference method gave the most accurate determination for tannin concentration (RMSEC = 2.6%, RMSEP = 9.4%, r = 0.995). The prediction of the mean degree of polymerization (mDP) of the tannins also gave a reasonable prediction (RMSEC = 6.7%, RMSEP = 10.3%, r = 0.958). These results represent the first step in the development of a spectroscopic methodology for the quantification of several phenolic compounds that are critical for wine quality.
Robust control of fed-batch high-cell density cultures: a simulation-based assessment
(2021) Ibanez, Francisco; Saa, Pedro A.; Barzaga, Lisbel; Duarte-Mermoud, Manuel A.; Fernandez-Fernandez, Mario; Agosin, Eduardo; Perez Correa, Jose Ricardo
Screening of COVID-19 cases through a Bayesian network symptoms model and psychophysical olfactory test
(CELL PRESS, 2021) Eyheramendy, Susana; Saa, Pedro A.; Undurraga, Eduardo A.; Valencia, Carlos; Lopez, Carolina; Mendez, Luis; Pizarro Berdichevsky, Javier; Finkelstein Kulka, Andres; Solari, Sandra; Salas, Nicolas; Bahamondes, Pedro; Ugarte, Martin; Barcelo, Pablo; Arenas, Marcelo; Agosin, Eduardo
The sudden loss of smell is among the earliest and most prevalent symptoms of COVID-19 when measured with a clinical psychophysical test. Research has shown the potential impact of frequent screening for olfactory dysfunction, but existing tests are expensive and time consuming. We developed a low-cost ($0.50/test) rapid psychophysical olfactory test (KOR) for frequent testing and a model-based COVID-19 screening framework using a Bayes Network symptoms model. We trained and validated the model on two samples: suspected COVID-19 cases in five healthcare centers (n = 926; 33% prevalence, 309 RT-PCR confirmed) and healthy miners (n = 1,365; 1.1% prevalence, 15 RT-PCR confirmed). The model predicted COVID-19 status with 76% and 96% accuracy in the healthcare and miners samples, respectively (healthcare: AUC = 0.79 [0.75-0.82], sensitivity: 59%, specificity: 87%; miners: AUC = 0.71 [0.63-0.79], sensitivity: 40%, specificity: 97%, at 0.50 infection probability threshold). Our results highlight the potential for low-cost, frequent, accessible, routine COVID-19 testing to support society's reopening.

Browsing by Author "Agosin, Eduardo"

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