Bio-Lubricants production from fish oil residue by transesterification with trimethylolpropane

The fatty acid ethyl esters mixture, a fish oil residue obtained after the extraction of omega-3 polyunsaturated fatty esters, has been converted into mixtures of mono-, di-, and triesters of trimethylolpropane by transesterification at 100-140¿°C under vacuum with sodium ethoxide as catalyst. This method has shown to be more efficient than the enzymatic transesterification using commercially available lipases. The crude reaction mixture (84% conversion of ethyl esters), enriched in trimethylolpropane triesters (96% selectivity) was characterized and its properties compared with those of the starting ethyl esters mixture and the trimethylolpropane esters obtained from vegetal sources

Biobased catalyst in biorefinery processes: Sulphonated hydrothermal carbon for glycerol esterification

Sulphonated hydrothermal carbon (SHTC), obtained from D-glucose by mild hydrothermal carbonisation and subsequent sulphonation with sulphuric acid, is able to catalyse the esterification of glycerol with dif- ferent carboxylic acids, namely, acetic, butyric and caprylic acids. Product selectivity can be tuned by sim- ply controlling the reaction conditions. On the one hand, SHTC provides one of the best selectivity towards 20 monoacetins described up to now without the need for an excess of glycerol. On the other hand, excellent selectivity towards triacylglycerides (TAG) can be obtained, beyond those described with other solid cata- lysts, including well-known sulphonic resins. Recovery of the catalyst showed partial deactivation of the solid. The formation of sulphonate esters on the surface, confirmed by solid state NMR, was the cause of this behaviour. Acid treatment of the used catalyst, with subsequent hydrolysis of the surface sulphonate 25 esters, allows SHTC to recover its activity. The higher selectivity towards mono- and triesters and its renewable origin makes SHTC an attractive catalyst in biorefinery processe

Severe Deoxygenation Event Caused by the 2011 Eruption of the Submarine Volcano Tagoro (El Hierro, Canary Islands)

The shallow, near-shore submarine volcano Tagoro erupted in October 2011 at the Mar de las Calmas marine reserve, south of El Hierro island. The injection of lava into the ocean had its strongest episode during November 2011 and lasted until March 2012. During this time, in situ measurements of dissolved oxygen were carried out, using a continuous oxygen sensor constantly calibrated with water samples. A severe deoxygenation was observed in the area, particularly during October-November 2011, which was one of the main causes of the high mortality observed among the local marine ecosystem. The measured O2 concentrations were as low as 7.71 µmol kg-1, which represents a -96% decrease with respect to unaffected waters. The oxygen depletion was found in the first 250 m of the water column, with peaks between 70-120 m depth. The deoxygenated plume covered an area of at least 464 km2, distributed particularly south and south-west of the volcano, with occasional patches found north of the island. The oxygen levels were also monitored through the following years, during the degassing stage of the volcano, when oxygen depletion was no longer observed. Additionally, during the eruption, an island-generated anticyclonic eddy interacted with the volcanic plume and transported it for at least 80 km, where the O2 measurements still showed a -8% decrease after mixing and dilution. This feature draws attention to the permanence and transport of volcanic plumes far away from their source and long after the emission.En prens

Emissions of Fe(II) and its kinetic of oxidation at Tagoro submarine volcano, El Hierro

The eruptive process that took place in October 2011 in the submarine volcano Tagoro off the Island of El Hierro and the subsequent degasification stage, five months later, have increased the concentration of TdFe(II) (Total dissolved iron(II)) in thewaters nearest to the volcanic edifice. In order to detect any variation in concentrations of TdFe(II) due to hydrothermal emissions, three cruiseswere carried out two years after the eruptive process in October 2013,March 2014 andMay 2015. The results fromthese cruises confirmed important positive anomalies in TdFe(II), which coincided with negatives anomalies in pHF,is (pH in free scale, at in situ conditions) located in the proximity of themain cone. Maximumvalues in TdFe(II) both at the surface, associated to chlorophyll a maximum, and at the sea bottom, were also observed, showing the important influence of organic complexation and particle re-suspension processes. Temporal variability studies were carried out over periods ranging from hours to days in the stations located over themain and two secondary cones in the volcanic edifice with positive anomalies in TdFe(II) concentrations and negative anomalies in pHF,is values. Observations showed an important variability in both pHF,is and TdFe(II) concentrations, which indicated the volcanic area was affected by a degasification process that remained in the volcano after the eruptive phase had ceased. Fe(II) oxidation kinetic studies were also undertaken in order to analyze the effects of the seawater properties in the proximities of the volcano on the oxidation rate constants and t1/2 (half-life time) of ferrous iron. The increased TdFe(II) concentrations and the low associated pHF,is values acted as an important fertilization event in the seawater around the Tagoro volcano at the Island of El Hierro providing optimal conditions for the regeneration of the area.En prens

Comparison of Maldi-Tof with gene sequencing in bacteria isolates from plants belonging to family Rhizobiaceae

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The natural ocean acidification and fertilization event caused by the submarine eruption of El Hierro

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Impact of the dosimetry approach on the resulting 90Y radioembolization planned absorbed doses based on 99mTc-MAA SPEC T-CT: is there agreement between dosimetry methods?

Background: Prior radioembolization, a simulation using 99mTc-macroaggregated albumin as 90Y-microspheres surrogate is performed. Gamma scintigraphy images (planar, SPECT, or SPECT-CT) are acquired to evaluate intrahepatic 90Y-microspheres distribution and detect possible extrahepatic and lung shunting. These images may be used for pre-treatment dosimetry evaluation to calculate the 90Y activity that would get an optimal tumor response while sparing healthy tissues. Several dosimetry methods are available, but there is still no consensus on the best methodology to calculate absorbed doses. The goal of this study was to retrospectively evaluate the impact of using different dosimetry approaches on the resulting 90Y-radioembolization pre-treatment absorbed dose evaluation based on 99mTc-MAA images. Methods: Absorbed doses within volumes of interest resulting from partition model (PM) and 3D voxel dosimetry methods (3D-VDM) (dose-point kernel convolution and local deposition method) were evaluated. Additionally, a new “Multi-tumor Partition Model” (MTPM) was developed. The differences among dosimetry approaches were evaluated in terms of mean absorbed dose and dose volume histograms within the volumes of interest. Results: Differences in mean absorbed dose among dosimetry methods are higher in tumor volumes than in non-tumoral ones. The differences between MTPM and both 3D-VDM were substantially lower than those observed between PM and any 3D-VDM. A poor correlation and concordance were found between PM and the other studied dosimetry approaches. DVH obtained from either 3D-VDM are pretty similar in both healthy liver and individual tumors. Although no relevant global differences, in terms of absorbed dose in Gy, between both 3D-VDM were found, important voxel-by-voxel differences have been observed. Conclusions: Significant differences among the studied dosimetry approaches for 90Y-radioembolization treatments exist. Differences do not yield a substantial impact in treatment planning for healthy tissue but they do for tumoral liver. An individual segmentation and evaluation of the tumors is essential. In patients with multiple tumors, the application of PM is not optimal and the 3D-VDM or the new MTPM are suggested instead. If a 3D-VDM method is not available, MTPM is the best option. Furthermore, both 3D-VDM approaches may be indistinctly used

Global diversity and biogeography of deep-sea pelagic prokaryotes

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Recent Trends in SST, Chl-a, Productivity and Wind Stress in Upwelling and Open Ocean Areas in the Upper Eastern North Atlantic Subtropical Gyre

The global upper ocean has been warming during the last decades accompanied with a chlorophyll-a (Chl-a) and productivity decrease. Whereas subtropical gyres show similar trends, Eastern Boundary Upwelling Systems are thought to increase in productivity due to increased trade winds. This study analyzes recent trends in sea surface temperature (SST), Chl-a, net primary production (NPP) and meridional wind stress in the Eastern North Atlantic subtropical gyre (NASE) in order to examine if the global trends can be detected in open ocean and upwelling areas and how the ocean biota responds. Satellite data of such variables of the last 15–40 years were analyzed to calculate mean trends in upwelling areas in the Canary upwelling system and open ocean areas around the Azores, Madeira and the Canary Islands. Our results show significant warming in the area with a maximum of 2.7°C per century for the Azores. Moreover, a general decreasing trend for Chl-a and NPP seems to be more evident in the permanent upwelling areas, which will be responsible for a loss of 0.13% of the global NPP per century. Our results also highlight a significant expansion of the oceanic desert area of 10% with an increase in unproductive days of up to 84 days in the last 20 years. The competitive relationship of stratification and wind stress in the Canary upwelling system might be a more plausible explanation for the decrease in Chl-a and NPP in upwelling areas linked to the increase in upwelling favorable wind stress and the surface warming.En prens