Electromagnetic freezing: Effects of weak oscillating magnetic fields on crab sticks

Since the earlier 2000s, electromagnetic freezers have been sold all over the world. According to the manufacturers, the oscillating magnetic fields (OMFs) applied by these devices are capable of avoiding ice damage in frozen foods. To assess the effectiveness of OMFs in preserving food quality, we froze crab sticks in a commercial electromagnetic freezer, both with (<2 mT, 6-59 Hz) and without OMF application. Crab sticks were also frozen in a conventional freezer, both with static- and forced-air conditions, to compare electromagnetic freezing with conventional methods. After 24 h and 1, 3, 6, 9, and 12 months of storage, we did not find any effect of the OMFs on the drip loss, water-holding capacity, toughness, and whiteness of the crab sticks frozen in the electromagnetic device. Moreover, no advantage of electromagnetic freezing over air-blast freezing was detected at the conditions tested. More experiments at larger magnetic field strength and wider frequency ranges are needed to have a complete view of the potential effects of OMFs on food freezing.This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project AGL2012-39756-C02-01. Antonio C. Rodríguez acknowledges the predoctoral contract BES-2013-065942 from MINECO, jointly financed by the European Social Fund, in the framework of the National Program for the Promotion of Talent and its Employability (National Sub-Program for Doctors Training).Peer reviewe

Effects of magnetic fields on freezing: Application to biological products

Magnetic freezing is nowadays established as a commercial reality mainly oriented towards the food market. According to advertisements, magnetic freezing is able to generate tiny ice crystals throughout the frozen product, prevent cell destruction, and preserve the quality of fresh food intact after thawing. If all these advantages were true, magnetic freezing would represent a significant advance in freezing technology, not only for food preservation but also for cryopreservation of biological specimens, such as cells, tissues, and organs. Magnetic fields (MFs) are supposed to act directly on water by orientating, vibrating and/or spinning molecules to prevent them from clustering and, thus, promote supercooling. However, many doubts exist about the real effects of MFs on freezing and the science behind the potential mechanisms involved. To provide a basis for extending the understanding of magnetic freezing, this paper presents a critical review of the materials published in the literature up to now, including both patents and experimental results. After examining the information available, it was not possible to discern whether MFs have an appreciable effect on supercooling, freezing kinetics, ice crystals, quality, and/or viability of the frozen products. Experiments in the literature frequently fail to identify and/or control all the factors that can play a role in magnetic freezing. Moreover, many of the comparisons between magnetic and conventional freezing are not correctly designed to draw valid conclusions and wide ranges of MF intensities and frequencies are unexplored. Therefore, more rigorous experimentation and further evidence are needed to confirm or reject the efficacy of MFs in improving the quality of frozen products.This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project AGL2012-39756-C02-01. A. C. Rodríguez acknowledges a predoctoral contract from MINECO, jointly financed by the European Social Fund, in the framework of the National Program for the Promotion of Talent and its Employability (National Sub-Program for Doctors Training).Peer reviewe

Methanogenesis at high temperature, high ionic strength and low pH in the volcanic area of Dallol, Ethiopia

The Dallol geothermal area originated as a result of seismic activity and the presence of a shallow underground volcano, both due to the divergence of two tectonic plates. In its ascent, hot water dissolves and drags away the subsurface salts. The temperature of the water that comes out of the chimneys is higher than 100C, with a pH close to zero and high mineral concentration. These factors make Dallol a polyextreme environment. So far, nanohaloarchaeas, present in the salts that form the walls of the chimneys, have been the only living beings reported in this extreme environment. Through the use of complementary techniques: culture in microcosms, methane stable isotope signature and hybridization with specific probes, the methanogenic activity in the Dallol area has been assessed. Methane production in microcosms, positive hybridization with the Methanosarcinales probe and the δC-values measured, show the existence of extensive methanogenic activity in the hydrogeothermic Dallol system. A methylotrophic pathway, carried out by Methanohalobium and Methanosarcina-like genera, could be the dominant pathway for methane production in this environment.Agencia Estatal de Investigación (AEI), grant MDM-2017-0737 (Unidad de Excelencia “María de Maeztu”-Centro de Astrobiología INTA-CSIC) and the Spanish Ministerio de Ciencia e Innovación (MICINN

Quantification of african monsoon runoff during last interglacial sapropel S5

Organic‐rich sapropel layers punctuate the eastern Mediterranean sedimentary sequence, recording deep‐sea anoxic events. The timing of sapropel deposition coincides with precession minima, which are associated with the northward migration of the monsoon rain belt over North Africa. The resultant increase in monsoon precipitation over the Sahara caused an increase in low‐δ 18 O freshwater runoff into eastern Mediterranean surface waters, which is reflected by negative δ 18 O anomalies in the records of planktic foraminiferal calcite. However, despite extensive research on sapropels, the magnitude of monsoon intensification and freshwater runoff, along with its influence on δ 18 O, remains elusive. Here, we present a quantification of African monsoon freshwater runoff into the eastern Mediterranean for the period of deposition of last interglacial sapropel S5 (~128.3–121.5 ka). Our method uses a box model of the Mediterranean Sea, which represents different water masses, and has been calibrated using δ 18 O from planktic foraminiferal species of different depth and seasonal habitats. The model was constrained with existing records of sea level and sea surface temperature then inverted to deconvolve the δ 18 O signal of the surface‐dwelling foraminiferal species Globigerinoides ruber (w) and calculate the freshwater runoff volume. Our calculated African monsoon runoff suggests large increases in freshwater discharge to the eastern Mediterranean (up to ~8.8 times the modern pre‐Aswan Nile discharge). Rapid onset of S5 deposition following the estimated increase in runoff strongly suggests a preconditioning of the eastern Mediterranean for sapropel deposition. Our study also provides insight into the stratification and warming of eastern Mediterranean surface waters during the S5 interval.Australian Research Council | Ref. FL120100050Australian Research Council | Ref. DE190100042Australia-New Zealand IODP Consortium | Ref. LE140100047Australia-New Zealand IODP Consortium | Ref. LE16010006

Anomalous high-pressure Jahn-Teller behavior in CuWO4

High-pressure optical-absorption measurements performed in CuWO4 up to 20 GPa provide experimental evidence of the persistence of the Jahn-Teller (JT) distortion in the whole pressure range both in the low-pressure triclinic and in the high-pressure monoclinic phase. The electron-lattice couplings associated with the eg(E⊗e) and t2g(T⊗e) orbitals of Cu2+ in CuWO4 are obtained from correlations between the JT distortion of the CuO6 octahedron and the associated structure of Cu2+ d-electronic levels. This distortion and its associated JT energy (EJT) decrease upon compression in both phases. However, both the distortion and associated EJT increase sharply at the phase-transition pressure (PPT=9.9  GPa), and we estimate that the JT distortion persists for a wide pressure range not being suppressed up to 37 GPa. These results shed light on the transition mechanism of multiferroic CuWO4, suggesting that the pressure-induced structural phase transition is a way to minimize the distortive effects associated with the toughness of the JT distortion.C.-Y. Tu is acknowledged for providing us the crystals used to perform the experiments. J. R.-F. is indebted to the FPI research grant (BES-2008-002043) and thanks C. Renero-Lecuna for fruitful discussions on the spectroscopic data. The authors thank the financial support from the MICINN of Spain under Grants No. MAT2010- 21270-C04-01, No. MAT2008-06873-C02-01/02, and No. CSD2007-00045

Effect of two days treatment with orlistat on plasma leptin in obese patients without weight loss

Objective: Little is known about the impact of orlistat on the leptin system. We studied the plasma leptin and satiety sensation response for two days of orlistat treatment without hypocaloric diet and weight loss. Material and methods: Twenty obese female subjects were recruited from our medical outpatient clinics. All of these subjects had previously received advice on dietary restriction and lifestyle modification, but remained obese with a stable body weight for at least six months before recruitment for the study. Results: Subjects were given 120 mg orlistat 3 times daily and were asked to maintain their usual diet. At baseline and two days after the treatment with orlistat, physical examination, hunger and blood analysis were repeated. There were no significant differences observed regarding energy dietary intake, body weight and waist-hip ratio, or in plasma glucose, insulin c-peptide concentrations. Only plasma leptin and triglycerides concentrations decreased (p: 0.0001 and 0.01 respectively). Decrease in plasma leptin concentration was positively correlated with changes observed in plasma triglycerides concentration (p: 0.01, r2: 0.45). Pre-dinner hunger increased and was negatively correlated with decrease in leptin (p: 0.0001, r2: 0.74) and triglycerides (p: 0.02, r2: 0.59). Conclusion: These data suggest that the partial fat malabsorption induced by the treatment with orlistat quickly reduces plasma triglycerides and leptin. This decrease is associated with increased appetite before intake following the main meal of the day

Accurate long-term air temperature prediction with Machine Learning models and data reduction techniques

In this paper, three customised Artificial Intelligence (AI) frameworks, considering Deep Learning, Machine Learning (ML) algorithms and data reduction techniques, are proposed for a problem of long-term summer air temperature prediction. Specifically, the prediction of the average air temperature in the first and second August fortnights, using input data from previous months, at two different locations (Paris, France) and (Córdoba, Spain), is considered. The target variable, mainly in the first August fortnight, can contain signals of extreme events such as heatwaves, like the heatwave of 2003, which affected France and the Iberian Peninsula. Three different computational frameworks for air temperature prediction are proposed: a Convolutional Neural Network (CNN), with video-to-image translation, several ML approaches including Lasso regression, Decision Trees and Random Forest, and finally a CNN with pre-processing step using Recurrence Plots, which convert time series into images. Using these frameworks, a very good prediction skill has been obtained in both Paris and Córdoba regions, showing that the proposed approaches can be an excellent option for seasonal climate prediction problems.This research has been partially supported by the European Union, through H2020 Project “CLIMATE INTELLIGENCE Extreme events detection, attribution and adaptation design using machine learning (CLINT)”, Ref: 101003876-CLINT. This research has also been partially supported by the project PID2020-115454GB-C21 of the Spanish Ministry of Science and Innovation (MICINN)