1,391 research outputs found
Environmentally friendly analysis of emerging contaminants by pressurized hot water extraction-stir bar sorptive extraction-derivatization and gas chromatography-mass spectrometry
This work describes the development, optimiza-
tion, and validation of a new method for the simultaneous
determination of a wide range of pharmaceuticals (beta-
blockers, lipid regulators
...
) and personal care products
(fragrances, UV filters, phthalates
...
) in both aqueous and
solid environmental matrices. Target compounds were
extracted from sediments using pressurized hot water ex-
traction followed by stir bar sorptive extraction. The first
stage was performed at 1,500 psi during three static extrac-
tion cycles of 5 min each after optimizing the extraction
temperature (50
–
150 °C) and addition of organic modifiers
(% methanol) to water, the extraction solvent. Next, aqueous
extracts and water samples were processed using polydime-
thylsiloxane bars. Several parameters were optimized for
this technique, including extraction and desorption time,
ionic strength, presence of organic modifiers, and pH. Fi-
nally, analytes were extracted from the bars by ultrasonic
irradiation using a reduced amount of solvent (0.2 mL) prior
to derivatization and gas chromatography
–
mass spectrome-
try analysis. The optimized protocol uses minimal amounts
of organic solvents (<10 mL/sample) and time (
≈
8 h/sam-
ple) compared to previous ex
isting methodologies. Low
standard deviation (usually below 10 %) and limits of de-
tection (sub-ppb) vouch for the applicability of the method-
ology for the analysis of target compounds at trace levels.
Once developed, the method was applied to determin
Microencapsulation techniques: a proposal for microencapsulated probiotics.
A la hora de utilizar probióticos, el principal problema que se presenta, es la escasa resistencia de estos a diferentes condiciones ambientales y tecnológicas. Las técnicas de microencapsulación son un buen método para proteger a estos microorganismos, sin embargo no todas las técnicas son apropiadas para los probióticos. En este artículo proponemos la técnica de gelificación interna, que por sus características permite la obtención de un tamaño de partícula adecuado y la supervivencia de los microorganismos.The main problem when probiotics are used is the low resistance of these to different environmental and technological conditions. The microencapsulation techniques are a good method in order to protect the probiotics, Nevertheless not all techniques of microencapsulation are suitable for probiotics. In this paper, we propose the internal gelification which allows us to obtain a suitable particle size and the survival of the microorganisms
The rate of X-ray-induced DNA double-strand break repair in the embryonic mouse brain is unaff ected by exposure to 50 Hz magnetic fi elds
Following in utero exposure to low dose radiation
(10 – 200 mGy), we recently observed a linear induction of DNA
double-strand breaks (DSB) and activation of apoptosis in the
embryonic neuronal stem/progenitor cell compartment. No
signifi cant induction of DSB or apoptosis was observed following
exposure to magnetic fi elds (MF). In the present study, we
exploited this in vivo system to examine whether exposure to MF
before and after exposure to 100 mGy X-rays impacts upon DSB
repair rates.
Materials and methods : 53BP1 foci were quantifi ed following
combined exposure to radiation and MF in the embryonic neuronal
stem/progenitor cell compartment. Embryos were exposed
in utero to 50 Hz MF at 300 m T for 3 h before and up to 9 h after
exposure to 100 mGy X-rays. Controls included embryos exposed
to MF or X-rays alone plus sham exposures.
Results : Exposure to MF before and after 100 mGy X-rays did not
impact upon the rate of DSB repair in the embryonic neuronal
stem cell compartment compared to repair rates following radiation
exposure alone.
Conclusions : We conclude that in this sensitive system MF do not
exert any signifi cant level of DNA damage and do not impede
the repair of X-ray induced damage
Dynamical Patterns of Cattle Trade Movements
Despite their importance for the spread of zoonotic diseases, our
understanding of the dynamical aspects characterizing the movements of farmed
animal populations remains limited as these systems are traditionally studied
as static objects and through simplified approximations. By leveraging on the
network science approach, here we are able for the first time to fully analyze
the longitudinal dataset of Italian cattle movements that reports the mobility
of individual animals among farms on a daily basis. The complexity and
inter-relations between topology, function and dynamical nature of the system
are characterized at different spatial and time resolutions, in order to
uncover patterns and vulnerabilities fundamental for the definition of targeted
prevention and control measures for zoonotic diseases. Results show how the
stationarity of statistical distributions coexists with a strong and
non-trivial evolutionary dynamics at the node and link levels, on all
timescales. Traditional static views of the displacement network hide important
patterns of structural changes affecting nodes' centrality and farms' spreading
potential, thus limiting the efficiency of interventions based on partial
longitudinal information. By fully taking into account the longitudinal
dimension, we propose a novel definition of dynamical motifs that is able to
uncover the presence of a temporal arrow describing the evolution of the system
and the causality patterns of its displacements, shedding light on mechanisms
that may play a crucial role in the definition of preventive actions
Dynamical Patterns of Cattle Trade Movements
Despite their importance for the spread of zoonotic diseases, our
understanding of the dynamical aspects characterizing the movements of farmed
animal populations remains limited as these systems are traditionally studied
as static objects and through simplified approximations. By leveraging on the
network science approach, here we are able for the first time to fully analyze
the longitudinal dataset of Italian cattle movements that reports the mobility
of individual animals among farms on a daily basis. The complexity and
inter-relations between topology, function and dynamical nature of the system
are characterized at different spatial and time resolutions, in order to
uncover patterns and vulnerabilities fundamental for the definition of targeted
prevention and control measures for zoonotic diseases. Results show how the
stationarity of statistical distributions coexists with a strong and
non-trivial evolutionary dynamics at the node and link levels, on all
timescales. Traditional static views of the displacement network hide important
patterns of structural changes affecting nodes' centrality and farms' spreading
potential, thus limiting the efficiency of interventions based on partial
longitudinal information. By fully taking into account the longitudinal
dimension, we propose a novel definition of dynamical motifs that is able to
uncover the presence of a temporal arrow describing the evolution of the system
and the causality patterns of its displacements, shedding light on mechanisms
that may play a crucial role in the definition of preventive actions
Assessing coastal artificial light and potential exposure of wildlife at a national scale: the case of marine turtles in Brazil
This is the final version. Available from Springer via the DOI in this record. Coastal areas provide critical nesting habitat for marine turtles. Understanding how artificial light might impact populations is key to guide management strategies. Here we assess the extent to which nesting populations of four marine turtle species—leatherback (Dermochelys coriacea), olive ridley (Lepidochelys olivacea), hawksbill (Eretmochelys imbricata) and two subpopulations of loggerhead (Caretta caretta) turtles—are exposed to light pollution across 604 km of the Brazilian coast. We used yearly night-time satellite images from two 5-year periods (1992–1996 and 2008–2012) from the US Air Force Defense Meteorological Satellite Programme (DMSP) to determine the proportion of nesting areas that are exposed to detectable levels of artificial light and identify how this has changed over time. Over the monitored time-frame, 63.7% of the nesting beaches experienced an increase in night light levels. Based on nest densities, we identified 54 reproductive hotspots: 62.9% were located in areas potentially exposed to light pollution. Light levels appeared to have a significant effect on nest densities of hawksbills and the northern loggerhead turtle stock, however high nest densities were also seen in lit areas. The status of all species/subpopulations has improved across the time period despite increased light levels. These findings suggest that (1) nest site selection is likely primarily determined by variables other than light and (2) conservation strategies in Brazil appear to have been successful in contributing to reducing impacts on nesting beaches. There is, however, the possibility that light also affects hatchlings in coastal waters, and impacts on population recruitment may take longer to fully manifest in nesting numbers. Recommendations are made to further this work to provide deeper insights into the impacts of anthropogenic light on marine turtles.National Council for Scientific and Technological Development (CNPq)University of ExeterU.S. Fish and Wildlife ServiceNatural Environment Research Counci
Characterisation of feline renal cortical fibroblast cultures and their transcriptional response to transforming growth factor beta 1
Chronic kidney disease (CKD) is common in geriatric cats, and the most prevalent pathology is chronic tubulointerstitial inflammation and fibrosis. The cell type predominantly responsible for the production of extra-cellular matrix in renal fibrosis is the myofibroblast, and fibroblast to myofibroblast differentiation is probably a crucial event. The cytokine TGF-β1 is reportedly the most important regulator of myofibroblastic differentiation in other species. The aim of this study was to isolate and characterise renal fibroblasts from cadaverous kidney tissue of cats with and without CKD, and to investigate the transcriptional response to TGF-β1
The central region of the msp gene of Treponema denticola has sequence heterogeneity among clinical samples, obtained from patients with periodontitis
<p>Abstract</p> <p>Background</p> <p><it>Treponema denticola </it>is an oral spirochete involved in the pathogenesis and progression of periodontal disease. Of its virulence factors, the major surface protein (MSP) plays a role in the interaction between the treponeme and host. To understand the possible evolution of this protein, we analyzed the sequence of the <it>msp </it>gene in 17 <it>T. denticola </it>positive clinical samples.</p> <p>Methods</p> <p>Nucleotide and amino acid sequence of MSP have been determined by PCR amplification and sequencing in seventeen <it>T. denticola </it>clinical specimens to evaluate the genetic variability and the philogenetic relationship of the <it>T. denticola msp </it>gene among the different amplified sequence of positive samples. In silico antigenic analysis was performed on each MSP sequences to determined possible antigenic variation.</p> <p>Results</p> <p>The <it>msp </it>sequences showed two highly conserved 5' and 3' ends and a central region that varies substantially. Phylogenetic analysis categorized the 17 specimens into 2 principal groups, suggesting a low rate of evolutionary variability and an elevated degree of conservation of <it>msp </it>in clinically derived genetic material. Analysis of the predicted antigenic variability between isolates, demonstrated that the major differences lay between amino acids 200 and 300.</p> <p>Conclusion</p> <p>These findings showed for the first time, the nucleotide and amino acids variation of the <it>msp </it>gene in infecting <it>T. denticola</it>, <it>in vivo</it>. This data suggested that the antigenic variability found in to the MSP molecule, may be an important factor involved in immune evasion by <it>T. denticola</it>.</p
Parasitosis intestinales en escolares de la ciudad de Valencia. Encuesta de prevalencia.
Fundamento: La importancia de la lucha contra las infecciones intestinales entre las que se incluyen las parasitarias radica en su alta prevalencia y su distribución mundial. El objeto del estudio es conocer la prevalencia de parásitos en heces en la población escolar de la ciudad de Valencia y se justifica en el desconocimiento de la endemia parasitaria, combinada con los importantes cambios demográficos y sociales por el fenómeno inmigratorio.Material y método: Se realiza un estudio descriptivo, de corte transversal con distribución de características y atributos de los sujetos. Muestra asignada por conglomerados entre la población (64.200 alumnos) asistente a centros de Educación Infantil (3-5 años) y Primaria (6-11 años) segmentada por estacionalidad. Tamaño muestral 1.031 niños, prevalencia esperada 21,8% y error de muestreo 2,5%. Se aplicó encuesta auto-cumplimentada y toma de muestra única de heces: bote de recogida con fijador y cinta de Graham para detección de entero-parásitos. Resultados: En el segmento estacional primavera-otoño se recuperaron 523 sujetos, (29,8% son población inmigrante). La prevalencia general de infección fue 27,4%. (IC95%: 23,58-31,22), que alcanza el 40,52% (IC95%: 32,5-47,8) en inmigrantes, RP: 2,45 (IC95%: 1,64-3,67, p<0,0001). Se detectan 11 especies entero-parasitarias, la más frecuente Blastocystis hominis: 14,9%, de los que 57,33% corresponden a escolares inmigrantes RP: 3,16 (IC95%: 2,08-4,79, p<0,0001). Al comparar el origen de los infectados por ciclos escolares se observan diferencias en E.Primaria que se acentúan con la edad, OR1ºciclo: 2,6 (IC95%: 1,2-5,4), OR2ºciclo: 3,15 (IC95%: 1,3-7,3), OR3ªciclo: 6,44 (IC95%: 2,05-20,18). No se observan diferencias por género ni globalmente ni entre los inmigrantes.Conclusiones: La prevalencia general de parasitación observada resulta relevante. En general los datos conocidos coinciden con nuestra encuesta en que el 89% de las parasitosis son por protozoos. Los nematodos suponen un 9% y, de ellos, el más frecuente es E vermicularis. Con otros trabajos consultados, realizados en los años 90 se comprueba un cambio del patrón entero-parasitario y responde al cambio sociodemográfico producido por la inmigración. La fuerza de asociación y la relación infectados/edad en niños inmigrantes pone de manifiesto la necesidad de una especial vigilancia
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