20 research outputs found
Sorption of platinum on immobilized microorganisms for its on-line preconcentration and chemiluminescent determination in water samples
Fungi of the type Aspergillus sp. were immobilized on a cellulosic resin and used as a biosorbent for the on-line preconcentration and separation of Pt(IV) ions prior to their chemiluminescent determination via flow injection analysis. Biosorption and elution conditions were optimized, and the results compared to biosorbents based on the use of Chlorella vulgaris algae and Saccharomyces cerevisiae yeast in terms of preconcentration and selective retention of Pt(IV). The immobilized fungi presented here have a high potential for use in platinum biosorption. The procedure exhibits the currently lowest limit of detection (0.02 ng mL−1 of Pt) and very high selectivity. The procedure was applied to the determination of Pt(IV) in river water, road run-off, and wastewater samples
Magnetic Resonance Imaging in Huntington's Disease.
Magnetic resonance imaging (MRI) is a noninvasive technique used routinely to image the body in both clinical and research settings. Through the manipulation of radio waves and static field gradients, MRI uses the principle of nuclear magnetic resonance to produce images with high spatial resolution, appropriate for the investigation of brain structure and function
Nanosilver : uses, migration and methods of determination
The rapid growth in the commercial application of silver nanoparticles (AgNPs)
will certainly increase the exposure to these metals among humans and in the environment.
Nano-size silver particles have a broad spectrum of antimicrobial activity
and therefore are incorporated into various materials, including medical textiles,
which claim to prevent infection, as well as more common textiles, like anti-odour
sportswear, underwear, socks and gloves. On the market there is also a variety of
home consumer products claiming to contain nanosilver, for example disinfecting
sprays (to disinfect hard surfaces, towels, sheets, and clothing), kitchen cutting
boards, washing machines, refrigerators, dishwashers, pillows and mattresses,
toothbrushes, toilet seats, water filters, and cosmetics. Nanosilver is added to food
contact materials to preserve the packaged food for a particularly long period of
time by inhibiting the growth of microbes. There is a number of in vitro studies showing
cytotoxic effects and genotoxic DNA damaging capacity of AgNPs to a variety
of mammalian cell types [24]. However, there are only a few in vivo studies on their
genotoxicity. Likely routes of human exposure to released nanoparticles include
inhalation, ingestion and dermal penetration. Evaluation of the health impact of
AgNPs requires information on how readily and in what forms this substance can
be released from the material. At present, the availability of such data is limited
(Tab. 1).
Size of metal-based nanoparticles is an important factor determining their
physical and chemical properties as well as their bioavailability and toxicity. The
methods used for the size characterisation of AgNPs in different matrices (consumer
products, biological and environmental samples) (Tab. 2), as well as for speciation
analysis of various forms of silver, namely AgNPs and silver ions, are reviewed
in this paper.
Off-line methods such as centrifugal ultrafiltration, (ultra)centrifugation, dialysis,
and cloud point extraction are used in order to distinguish between nanoparticles
and dissolved forms of silver. Field-flow fractionation (FFF) in different
modes is used for nanoparticle size dependent separation [50]. Size-resolved AgNPs
fractions are further characterised by on-line detectors, such as UV-Vis, ICP OES or
ICP MS. ICP MS in single-particle detection mode is used for simultaneous determination
of nanosilver and silver ions [38]. The application of capillary electrophoresis
[40] and liquid chromatography [41, 42] for the separation of nano and ionic
forms of silver is also discussed in this work
Neurobiological features and response to eye movement desensitization and reprocessing treatment of posttraumatic stress disorder in patients with breast cancer
Appraisal of Biosorption for Recovery, Separation and Determination of Platinum, Palladium and Rhodium in Environmental Samples
Operationalizing compensation over time in neurodegenerative disease
In pre-clinical Huntington's disease, normal behaviour is maintained despite neurodegeneration, suggesting a mechanism of compensation. Gregory, Long et al. present two mathematical models of compensation over time and their operationalisation for neuroimaging