60 research outputs found
Misused terms in analytical chemistry with emphasis on ultrasound application
A wide number of analytical terms have been applied erroneously for many years by analytical chemists, and they apply at present yet, by considering the time makes their use correct. The question is, may precedents validate the present use of incorrect scientific terms? Misused terms are found along the analytical process, starting with giving the name of the sample to the exiguous fraction of the original sample that reaches the detector or the high-resolution equipment after sample pretreatment and sample preparation. All the steps of the analytical process are considered in this article, with special emphasis on sample preparation and, within this, on the use of ultrasound, mainly for assisting extraction more unequivocally named as leaching or lixiviation. A call of attention in this respect is considered by the author to be of help to the analytical community
Flow injection determination of total catechins and procyanidins in white and red wines
An easily automatable flow-injection (FI) method for the determination of total catechins is reported. The method is based on the reaction of vanillin in acid medium to yield a coloured product with maximum absorption at 500 nm. After optimisation by the univariate and multivariate approaches as required, the linear range was established (between 10 and 90 mgL-1 and 10 and 250 mgL-1 for white and red wines, respectively). Then, the assessment of the proposed versus the reference method was studied in terms of repeatability (2.57 mgL-1), reproducibility (3.56 mgL-1) (no significant differences were found), detection and quantification limits (not far from those of the reference method and always sufficient for the determination of catechins in any type of wine), traceability (excellent correlation under all conditions) and sample throughput (23 samples h-1 for the proposed method versus 3 samples h-1 for the reference method)
Use of superheated liquids for the extraction of non-volatile compounds from wood: HPLC studies
A study of the extraction of oak wood compounds using superheated water-ethanol mixtures ranging from 10 to 60% ethanol is reported. Identification and characterization of the extracted compounds have been made by high performance liquid chromatography. The extraction has been performed using the static mode by single or repetitive cycles. The variables affecting the extraction process have been studied and their optimum values established (extraction time: 50 min; pressure: 40 atm; extraction temperature: 180Âș C). The study allows to compare the non-volatile polyphenol fractions obtained in this way with those present in commercial samples with fully agreement between them. In addition, the method allows manipulation of the extract composition by changing the working pressure, temperature and water-ethanol ratio
Method for monitoring urea and ammonia in wine and must by flow injection-pervaporation
An easy to automate flow-injection-pervaporation method for monitoring urea and ammonia in must and wine was developed. The method is based on separation of the ammonia from the sample matrix by pervaporation followed by its reaction with salicylate, hypochlorite and nitroprusside to form a diazonium salt with maximum absorption at 647 nm. Conversion of urea into ammonia catalysed by urease was mandatory before pervaporation. After optimisation by either the univariate or multivariate approaches as required, the linear range was established (between 0 and 25 mg l-1) for both analytes. Then, the assessment of the proposed method versus a reference one for urea and ammonia was studied in terms of repeatability (0.52 mg l-1 and 0.43 mg l-1, respectively), reproducibility (1.34 mg l-1 and 1.21 mg l-1, respectively), detection and quantification limits (LOD=0.9 and 0.6 mg l-1, LQ=1.02 and 0.67 mg l-1, respectively) and traceability. The sample throughput was 16 samples h-1. The method can be applied to the monitoring of the target analytes in must and young wine in order to control their contents, preventing formation of ethyl carbamate
Quantitative proteomic analysis of Pseudomonas pseudoalcaligenes CECT5344 in response to industrial cyanide-contain ing wastewaters using Liquid Chromatography- Mass Spectrometry/Mass Spectrometry (LC- MS/MS)
Biological
treatments
to degrade
cyanide
are
a powerful
technology
for
cyanide
removal
from
industrial
wastewaters.
It has
been
previously
demonstrated
that
the
alkaliphilic
bacterium
Pseudomonas
pseudoalcali
genes
CECT5344
is able
to use
free
cyanide
and
several
metal
â
cyanide
complexes
as
the
sole
nitrogen
source.
In this
work,
the
strain
CECT5344
has
been
used
for
detoxification
of the
different
chemical
forms
of cyanide
that
are
present
in alkaline
wastewaters
from
the
jewelry
industry.
This
liquid
residue
also
contains
large
concentration
s
of metals
like
iron,
copper
and
zinc,
making
this
wastewater
even
more
toxic.
To
elucidate
the
molecular
mechanisms
involved
in the
bioremediation
process,
a quantitative
proteomic
anal-
ysis
by
LC-MS/MS
has
been
carried
out
in
P
.
pseudoalcaligene
s
CECT5344
cells
grown
with
the
jewelry
residue
as
sole
nitrogen
source.
Different
proteins
related
to cyanide
and
cyanate
assimilation,
as
well
as
other
proteins
involved
in transport
and
resistance
to metals
were
induced
by
the
cyanide-cont
aining
jewelry
residue.
GntR-like
regulatory
proteins
were
also
induced
by
this
industrial
residue
and
mutational
analysis
revealed
that
GntR-like
regulatory
proteins
may
play
a role
in the
regulation
of cyanide
assimilation
in
P
.
pseudoalcaligene
s
CECT5344.
The
strain
CECT5344
has
been
used
in a batch
reactor
to remove
at pH
9 the
dif-
ferent
forms
of cyanide
present
in industrial
wastewaters
from
the
jewelry
industry
(0.3
g/L,
ca
.
12
mM
total
cyanide,
including
both
free
cyanide
and
metal
â
cyanide
complexes).
This
is
the
first
report
describing
the
biological
removal
at alkaline
pH
of such
as
elevated
concentra-
tion
of cyanide
present
in a heterogeneou
s mixture
from
an
industrial
source
Biological and Health-promoting Activity of Vinification Byproducts Produced in Spanish Vineyards
Several by-products are produced in the Spanish agricultural system. Among them, fresh and vinifiedgrape skins represent an abundant source of phenols with a potential nutraceutical value. Fresh grape skinextracts (FGSE) and vinification of grape skin extracts (VGSE) obtained by a microwave-assisted methodhave been chemically and biologically characterised. Their role in the maintenance of genetic stabilitywas stated by in vivo genotoxic and antigenotoxic evaluations (Drosophilla melanogaster wing spot test), aswell as by their potential chemopreventive effect (in an HL60 in vitro model). Total phenolic, anthocyaninand resveratrol contents were chemically characterised in the two extracts, showing some qualitativedifferences. Both extracts and resveratrol were not mutagenic in the Drosophila somatic mutation andrecombination tests, and exerted antigenotoxic activities against hydrogen peroxide. They also showedcytotoxic activity to HL60 leukaemia cells, with an IC50 of 4.5ÎŒL/mL, 4.6ÎŒL/mL and 98ÎŒM respectively andinduced apoptotic internucleosomic fragmentation in the HL60 cell line
Evolution of the use of corticosteroids for the treatment of hospitalised COVID-19 patients in Spain between March and November 2020: SEMI-COVID national registry
Objectives: Since the results of the RECOVERY trial, WHO recommendations about the use of corticosteroids (CTs) in COVID-19 have changed. The aim of the study is to analyse the evolutive use of CTs in Spain during the pandemic to assess the potential influence of new recommendations. Material and methods: A retrospective, descriptive, and observational study was conducted on adults hospitalised due to COVID-19 in Spain who were included in the SEMI-COVID- 19 Registry from March to November 2020. Results: CTs were used in 6053 (36.21%) of the included patients. The patients were older (mean (SD)) (69.6 (14.6) vs. 66.0 (16.8) years; p < 0.001), with hypertension (57.0% vs. 47.7%; p < 0.001), obesity (26.4% vs. 19.3%; p < 0.0001), and multimorbidity prevalence (20.6% vs. 16.1%; p < 0.001). These patients had higher values (mean (95% CI)) of C-reactive protein (CRP) (86 (32.7-160) vs. 49.3 (16-109) mg/dL; p < 0.001), ferritin (791 (393-1534) vs. 470 (236- 996) ”g/dL; p < 0.001), D dimer (750 (430-1400) vs. 617 (345-1180) ”g/dL; p < 0.001), and lower Sp02/Fi02 (266 (91.1) vs. 301 (101); p < 0.001). Since June 2020, there was an increment in the use of CTs (March vs. September; p < 0.001). Overall, 20% did not receive steroids, and 40% received less than 200 mg accumulated prednisone equivalent dose (APED). Severe patients are treated with higher doses. The mortality benefit was observed in patients with oxygen saturation </=90%. Conclusions: Patients with greater comorbidity, severity, and inflammatory markers were those treated with CTs. In severe patients, there is a trend towards the use of higher doses. The mortality benefit was observed in patients with oxygen saturation </=90%
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