724 research outputs found
Evaluation of the adsorption capacity of a new cellulose-based polymer
A novel cellulose-based polymer, dicarboxymethyl cellulose (DCMC), was synthesized from cellulose and sodium 2-bromomalonate. Inductively coupled plasma atomic emission spectrometry (ICP-AES) and Fourier-transform infrared spectroscopy (FTIR) were employed to characterize the polymer. The size of the particles ranged between 10 and 100 µm.
Equilibrium and kinetic adsorption studies were performed to evaluate its suitability for methylene blue removal at different pH. Equilibrium adsorption data was analyzed using Langmuir and Freundlich isotherms. At pH = 3, adsorption isotherms followed the Langmuir model with a maximum adsorption capacity of 887.6 mg/g. At pH = 6.4, the adsorption isotherms produced an S-shape and were fitted with the Sips model, giving
a maximum uptake of 1354.6 mg/g. Pseudo second-order kinetic model provided the best fit of the experimental data. The reusability of DCMC was evaluated. After the first cycle, adsorption decreased 30%. Adsorption coupled with membrane filtration allowed complete removal.
The adsorption of cytochrome C was evaluated. The adsorption process followed the Langmuir adsorption isotherm, giving a maximum uptake of 1279.6 mg/g. Pseudo second-order kinetic model adjusted well the experimental data. DCMC was successfully regenerated and reused without compromising performance. After three cycles, adsorption efficiency was above 90%
The effect of dicarboxymethyl cellulose on the prevention of protein haze formation on white wine
Funding Information: This research was funded by the Associate Laboratory for Green Chemistry-LAQV, which is financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020) and by Funda??o para a Ci?ncia e a Tecnologia (FCT) under the PhD grant DFA/BD/5529/2020. FCT/MCTES is also acknowledged for the National NMR Facility (RECI/BBB-BQB/0230/2012 and RECI/BBB-BEP/0124/2012). We acknowledge the NMR laboratory and the analysis laboratory at LAQV REQUIMTE, Chemistry Department, NOVA School of Science and Technology, Portugal for the NMR, ICP-AES and XRD data obtained. We thank Enartis for sharing their knowledge, insight, and experience. Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Wine clarity is a critical aspect in the commercialization of white wines. The formation of wine haze can be attributed to the aggregation and precipitation of heat-unstable wine proteins. Bentonite fining is the commonly used method in winemaking for protein removal, but it is responsible for loss of wine volume and quality. Dicarboxymethyl cellulose (DCMC) was developed as a potential alternative to bentonite. Water-insoluble DCMC was prepared via catalyzed heterogeneous etherification using sodium chloromalonate and potassium iodide. White wine fining trials were benchmarked with different dosages of DCMC against a bentonite. A high-performance liquid chromatography method was optimized for protein quantification. The samples underwent heat stability tests to evaluate wine turbidity before and after fining. Results show that DCMC successfully reduced the wine protein content and turbidity. DCMC produced heat-stable wines with dosages higher than 0.25 g/L. The innovative application of DCMC in the wine sector shows potential due to its ability to stabilize white wines while overcoming problems associated with bentonite, such as lees production and loss of wine, contributing to a more sustainable process.publishersversionpublishe
A novel cellulose-based polymer for efficient removal of methylene blue
UID/QUI/50006/2019A novel cellulose-based cross-linked polymer, dicarboxymethyl cellulose (DCMC), has been synthesized and used for methylene blue (MB) removal. Inductively coupled plasma atomic emission spectrometry (ICP-AES), Fourier-transform infrared spectroscopy (FTIR), nitrogen porosimetry, and optical microscopy were employed to characterize the structure of the cellulose-based adsorbent. The number of carboxylate groups per gram of polymer (CG) was calculated with sodium content determined by ICP-AES. Systematic equilibrium and kinetic adsorption studies were performed to assess the polymer suitability for dye removal. The effect of pH on its adsorption capacity was also studied and the equilibrium adsorption data was analyzed using Langmuir, Freundlich, and Sips isotherms. At pH = 3, the adsorption isotherms followed the Langmuir model with a maximum adsorption capacity of 887.6 mg/g. At pH = 6.4, the adsorption isotherms produced S-shape curves and were best fitted with the Sips model. The maximum MB uptake increased to 1354.6 mg/g. Pseudo first-order and second-order models were used to fit the kinetic data. A pseudo second-order kinetic model provided the best correlation for the adsorption of MB onto DCMC. Adsorption coupled with membrane filtration achieved 95% methylene blue removal and DCMC can be successfully regenerated and reused in consecutive experiments.publishersversionpublishe
Yellowtail flounder, redfish (Sebastes spp.) and witch flounder indices from the Spanish Survey conducted in Divisions 3NO of the NAFO Regulatory Area
Since 1995, Spain carries out a spring stratified random bottom trawl survey in Div. 3NO of the NAFO
Regulatory Area. Total mean catches, biomass and mean numbers for yellowtail flounder (Limanda ferruginea)
are presented for the period 1995-8 for redfish (Sebastes spp.) for the period 1997-2018 and for witch flounder
(Glyptocephalus cynoglossus) for the period 2002-2018. Detailed indices are presented from 2013.
Yellowtail flounder indices do not show a clear trend. Biomass increased from 1997 to 1999 has maintained
almost constant values until 2013 and then decreased in 2014-2018. Redfish indices oscillate greatly over time,
probably because the gear does not sample adequately aggregating pelagic species. There was a sharp increase
in 2009 and since then until 2015, biomass fluctuated maintaining higher values than before 2009. In 2016
biomass dropped and increase again in 2017-2018 to the 2012 level. The 3N division comprises around the
90% of the total biomass in the last years. Good year classes have not been registered recently. Length
distribution in thousands (abundance) by Division and year since 2002 is presented. Following the trend of the
biomass, most of the abundance corresponds to Division 3N. Witch flounder is very scarce and its indices
fluctuated throughout the series reaching the minimum value in 2014 and 2018, with an increasing trend in
the middle time. Recruitment was quite good at the beginning of the series but poor in recent years
Biomass and length distribution for roughhead grenadier, thorny skate, white hake, squid and capelin from the surveys conducted by Spain in NAFO 3NO
Data for roughhead grenadier (Macrourus berglax), thorny skate (Amblyraja radiata) and white hake
(Urophycis tenuis) from the Spanish Spring survey are presented. Abundance and biomass were estimated for
roughhead grenadier and thorny skate for the period 1997-2019 and for white hake for the period 2001-2019.
The length distribution is presented as numbers per haul stratified mean catches for the last five years (2015-
2019). The roughhead grenadier indices showed no discernible trend during the whole series, reaching a
maximum in 2004 and a minimum in 2019. In 2017 and 2018, a quite good presence of small and medium
lengths (1.5-19.5 cm) can be seen. Thorny skate indices follow a large oscillating trend, dropping in 2007 and
has been since then more or less stables at a low level, reaching the minimum of the series by far in 2019. In
2017 there is a discrete presence of length between 12 and 18 cm. White hake indices were highest in 2001
and then showed an overall decreasing trend until 2008 with low values, generally increasing since then with
some fluctuations. The 2019 biomass is the second lowest of the period studied. Small recruitment events were
detected in 2004, 2012 and 2013, with individuals between 16-26 cm. In 2017 the highest numbers are at small
lengths, between 20 and 24 cm, being around 34 cm in 2018. In 2019, the mode is around 8 cm. The estimated
biomass of squid is inconstant and very low in general. There were no catches of squid during the 2002 and
2013-2015 surveys. In 2018 and 2019, a step increase in biomass was observed during the survey, being 5.5
and 7 times, respectively, the third value of the series in 2011. Length samples were taken in 2011, 2017 and
2019. The lengths range between 3.5 and 19 cm. Capelin biomass reached a maximum in 2012, decreasing
sharply since then until 2017. In 2018 the index increased to a level similar to that in the early 2000s,
decreasing slightly in 201
Biomass and length distribution for roughhead grenadier, thorny skate and white hake from the surveys conducted by Spain in NAFO 3NO
Data for roughhead grenadier (Macrourus berglax), thorny skate (Amblyraja radiata) and white hake (Urophycis tenuis) from the Spanish Spring survey are presented. Abundance and biomass were estimated for roughhead grenadier and thorny skate for the period 1997-2015 and for white hake for the period 2001-2015. The length distribution is presented as numbers per haul stratified mean catches for the last five years (2011-2015). The roughhead grenadier indices showed no discernible trend until 2012, reaching a maximum in 2004 - 2006 and afterwards stabilised at levels slightly higher than in the early years. In the last two years a decline was appreciated in the indices, reaching in 2014 one of the lowest values of the entire time-series, increasing again in 2015. Thorny skate indices follow a large oscillating trend, dropping in 2007 and being since then more or less stables at a low level, reaching the minimum of the series in 2014. White hake indices were highest in 2001 and then showed an overall decreasing trend until 2008 with low values. Indices increased since then until 2013 but declined again in 2014, increasing sligthly in 2015. A small recruitment event was detected in 2005 and in 2013, with individuals between 16 - 26 cm.Postprint0,000
Yellowtail flounder, redfish (Sebastes spp.) and witch flounder indices from the Spanish Survey conducted in Divisions 3NO of the NAFO Regulatory Area
Since 1995, Spain carries out a spring stratified random bottom trawl survey in Div. 3NO of the NAFO
Regulatory Area. Total mean catches, biomass and mean numbers for yellowtail flounder (Limanda ferruginea)
are presented for the period 1995-2019, for redfish (Sebastes spp.) for the period 1997-2019 and for witch
flounder (Glyptocephalus cynoglossus) for the period 2002-2019. Detailed indices are presented from 2015.
Yellowtail flounder indices do not show a clear trend between 1999 and 2016. The 2017-2019 values were
lower than the 1998 one. There has not been good recruitment in recent years. Redfish indices oscillate greatly
over time, probably because the gear does not sample adequately aggregating pelagic species. There was a
sharp increase in 2009 and since then until 2015, biomass fluctuated maintaining higher values than before
2009. In 2016 biomass dropped and increase again in 2017-2019 to or below the 2012 level. The 3N division
comprises around the 90% of the total biomass in the last years. Good year classes have not been registered
recently. Abundance by Division shows since 2002 shows the same trend of the biomass; most of the abundance
corresponds to Division 3N. Witch flounder is very scarce and its indices fluctuated throughout the series
reaching a low level in 2014 and 2018, with an increasing trend in the middle time. The 2019 value is the lowest
of the series, being less than 50% of 2014 value. Recruitment was quite good at the beginning of the series but
poor in recent years
Yellowtail flounder, redfish (Sebastes spp.) and witch flounder indices from the Spanish Survey conducted in Divisions 3NO of the NAFO Regulatory Area
Since 1995, Spain carries out a spring stratified random bottom trawl survey in Div. 3NO of the NAFO Regulatory Area. Total mean catches, biomass and mean numbers for yellowtail flounder (Limanda ferruginea) are presented for the period 1995-2015, for redfish (Sebastes spp.) for the period 1997-2015 and for witch flounder (Glyptocephalus cynoglossus) for the period 2002-2015. Detailed indices are presented from 2011. Yellowtail flounder indices do not show a clear trend. Biomass increased from 1997 to 1999 and then remained almost constant throughout all the period, decreasing slightly in 2014 and 2015. Redfish indices oscillate greatly over time, probably because the gear does not sample adequately aggregating pelagic species. There was a sharp increase in 2009 and since then has maintained higher values than before 2009, comprising the 3N around the 90% of the total biomass in the last years. In 2014 all indices decreased, increased again in 2015 in both Divisions. Good year classes have not been registered recently. Witch flounder is very scarce and its indices show a general decreasing trend throughout the period (2002-2015) remaining at very low levels. Recruitment was quite good at the beginning of the series but very poor in recent years.Postprint0,000
Yellowtail flounder, redfish (Sebastes spp.) and witch flounder indices from the Spanish Survey conducted in Divisions 3NO of the NAFO Regulatory Area
Since 1995, Spain carries out a spring stratified random bottom trawl survey in Div. 3NO of the
NAFO Regulatory Area. Total mean catches, biomass and mean numbers for yellowtail flounder
(Limanda ferruginea) are presented for the period 1995-2017, for redfish (Sebastes spp.) for the
period 1997-2017 and for witch flounder (Glyptocephalus cynoglossus) for the period 2002-2017.
Detailed indices are presented from 2013. Yellowtail flounder indices do not show a clear trend.
Biomass increased from 1997 to 1999 and then remained almost constant throughout all the
period, decreasing slightly in 2014-2017. The 2017 value is the lowest since 1998. Redfish indices
oscillate greatly over time, probably because the gear does not sample adequately aggregating
pelagic species. There was a sharp increase in 2009 and since then until 2015, biomass fluctuated
maintaining higher values than before 2009. In 2016 biomass dropped and increase again in 2017
to the 2012 level. The 3N division comprises around the 90% of the total biomass in the last years.
Good year classes have not been registered recently. Witch flounder is very scarce and its indices
fluctuated throughout the series reaching the minimum value in 2014 and increasing since 2015.
2017 value is among the highest in the series. Recruitment was quite good at the beginning of the
series but poor in recent year
Dopamine D4 receptor activation counteracts nigrostriatal pathway activation by morphine: relevance in drug addiction.
Morphine induces dopamine release in the caudate putamen (CPu), which promotes stereotyped behavior and habit learning for drug-seeking and –taking. Nigrostriatal pathway stimulation by morphine is due to a removal of tonic inhibition arising from SNr GABA interneurons on SNc dopaminergic neurons through the mu opioid receptor (MOR). Long-term morphine exposure produces a series of adaptations in SNc dopamine neurons, which affect neuron excitability and dopamine output to CPu. We have previously shown that dopamine D4 receptor (D4R) stimulation counteracts acute and chronic morphine-induced accumulation of several transcription factors in the CPu (Gago et al., 2011 Brain Res.). Since D4R is expressed in the SNr (Rivera et al., Brain Res. 2003), we postulate that a functional D4R-MOR interaction at the midbrain level could exists.
We have investigated the role of D4R in the morphine-induced nigroestriatal dopamine metabolism in the rat brain using biochemical and immunohistochemical techniques. We also have studied the influence of D4R on morphine-induced morphological changes in SNc dopamine neurons using both immunohistochemical and image analysis techniques. Finally, we examined a possible underlying mechanism of the D4R-MOR interaction at the SN level using in vitro quantitative receptor autoradiography.
We have found that D4R activation restores dopamine metabolism in the nigroestriatal pathway after acute morphine treatment and prevents morphine-induced rise of tyroxine hydroxylase and dopamine transporter. Rats receiving a continuous treatment of morphine (6 days) showed SNc dopamine neurons with smaller size and higher circularity index compared with the controls animals. These morphine-induced morphological adaptatives changes were prevented when a D4R agonist (PD168,077) was administered at the same time with morphine. Autoradiographic studies demonstrated that the D4R agonist reduce the affinity of MOR. The present study provides evidence for the existence of a fully blocking effect of the D4R on the activation of dopaminergic nigroestriatal pathway by morphine.Financiación: P09-CVI- 4702 (Proyecto de Excelencia de la Junta de Andalucía
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