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Plasma Atomic Emission Spectroscopy (plasma + atomic_emission_spectroscopy)
Selected AbstractsVariable-field relaxometry of iron-containing human tissues: a preliminary studyCONTRAST MEDIA & MOLECULAR IMAGING, Issue 4 2009Aline Hocq Abstract Excess iron is found in brain nuclei from neurodegenerative patients (with Parkinson's, Alzheimer's and Huntington's diseases) and also in the liver and spleen of cirrhosis, hemochromatosis and thalassaemia patients. Ferritin, the iron-storing protein of mammals, is known to darken T2 -weighted MR images. Understanding NMR tissue behavior may make it possible to detect those diseases, to follow their evolution and finally to establish a protocol for non-invasive measurement of an organ's iron content using MRI methods. In this preliminary work, the MR relaxation properties of embalmed iron-containing tissues were studied as well as their potential correlation with the iron content of these tissues. Relaxometric measurements (T1 and T2) of embalmed samples of brain nuclei (caudate nucleus, dentate nucleus, globus pallidus, putamen, red nucleus and substantia nigra), liver and spleen from six donors were made at different magnetic fields (0.00023,14 T). The influence of the inter-echo time on transverse relaxation was also studied. Moreover, iron content of tissues was determined by inductively coupled plasma atomic emission spectroscopy. In brain nuclei, 1/T2 increases quadratically with the field and depends on the inter-echo time in CPMG sequences at high fields, both features compatible with an outer sphere relaxation theory. In liver and spleen, 1/T2 increases linearly with the field and depends on the inter-echo time at all fields. In our study, a correlation between 1/T2 and iron concentration is observed. Explaining the relaxation mechanism for these tissues is likely to require a combination of several models. The value of 1/T2 at high field could be used to evaluate iron accumulation in vivo. In the future, confirmation of those features is expected to be achieved from measurements of fresh (not embalmed) human tissues. Copyright © 2009 John Wiley & Sons, Ltd. [source] Genetically Engineered Phage Fibers and Coatings for Antibacterial ApplicationsADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Joan Y. Mao Abstract Multifunctionality can be imparted to protein-based fibers and coatings via either synthetic or biological approaches. Here, potent antimicrobial functionality of genetically engineered, phage-based fibers and fiber coatings, processed at room temperature, is demonstrated. Facile genetic engineering of the M13 virus (bacteriophage) genome leverages the well-known antibacterial properties of silver ions to kill bacteria. Predominant expression of negatively charged glutamic acid (E3) peptides on the pVIII major coat proteins of M13 bacteriophage enables solution-based, electrostatic binding of silver ions and subsequent reduction to metallic silver along the virus length. Antibacterial fibers of micrometer-scale diameters are constructed from such an E3-modified phage via wet-spinning and glutaraldehyde-crosslinking of the E3-modified viruses. Silverization of the free-standing fibers is confirmed via energy dispersive spectroscopy and inductively coupled plasma atomic emission spectroscopy, showing ,0.61,µg cm,1 of silver on E3,Ag fibers. This degree of silverization is threefold greater than that attainable for the unmodified M13,Ag fibers. Conferred bactericidal functionality is determined via live,dead staining and a modified disk-diffusion (Kirby,Bauer) measure of zone of inhibition (ZoI) against Staphylococcus epidermidis and Escherichia coli bacterial strains. Live,dead staining and ZoI distance measurements indicate increased bactericidal activity in the genetically engineered, silverized phage fibers. Coating of Kevlar fibers with silverized E3 phage exhibits antibacterial effects as well, with relatively smaller ZoIs attributable to the lower degree of silver loading attainable in these coatings. Such antimicrobial functionality is amenable to rapid incorporation within fiber-based textiles to reduce risks of infection, biofilm formation, or odor-based detection, with the potential to exploit the additional electronic and thermal conductivity of fully silverized phage fibers and coatings. [source] Low-Temperature Atomic Layer-Deposited TiO2 Films with Low PhotoactivityJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2009Xinhua Liang Atomic layer deposition (ALD) has been successfully utilized for the conformal and uniform deposition of ultrathin titanium dioxide (TiO2) films on high-density polyethylene (HDPE) particles. The deposition was carried out by alternating reactions of titanium tetraisopropoxide and H2O2 (50 wt% in H2O) at 77°C in a fluidized bed reactor. X-ray photoelectron spectroscopy confirmed the deposition of TiO2 and scanning transmission electron microscopy showed the conformal TiO2 films deposited on polymer particle surfaces. The TiO2 ALD process yielded a growth rate of 0.15 nm/cycle at 77°C. The results of inductively coupled plasma atomic emission spectroscopy suggested that there was a nucleation period, which showed the reaction mechanism of TiO2 ALD on HDPE particles without chemical functional groups. TiO2 ALD films deposited at such a low temperature had an amorphous structure and showed a much weaker photoactivity intensity than common pigment-grade anatase TiO2 particles. [source] Deferasirox removes cardiac iron and attenuates oxidative stress in the iron-overloaded gerbil,AMERICAN JOURNAL OF HEMATOLOGY, Issue 9 2009Rabaa M. Al-Rousan Iron-induced cardiovascular disease is the leading cause of death in iron-overloaded patients. Deferasirox is a novel, once daily oral iron chelator that was recently approved for the treatment of transfusional iron overload. Here, we investigate whether deferasirox is capable of removing cardiac iron and improving iron-induced pathogenesis of the heart using the iron overload gerbil model. Animals were randomly divided into three groups: control, iron overload, and iron overload + deferasirox treatment. Iron-dextran was given 100 mg/kg per 5 days i.p for 10 weeks. Deferasirox treatment was taken post iron loading and was given at 100 mg/kg/day p.o for 1 or 3 months. Cardiac iron concentration was determined by inductively coupled plasma atomic emission spectroscopy. Compared with the untreated group, deferasirox treatment for 1 and 3 months decreased cardiac iron concentration 17.1% (P = 0.159) and 23.5% (P < 0.05), respectively. These treatment-associated reductions in cardiac iron were paralleled by decreases in tissue ferritin expression of 20% and 38% at 1 and 3 months, respectively (P < 0.05). Using oxyblot analysis and hydroethidine fluorescence, we showed that deferasirox significantly reduces cardiac protein oxidation and superoxide abundance by 36 and 47.1%, respectively (P < 0.05). Iron-induced increase in oxidative stress was also associated with increased phosphorylation of ERK-, p38-, and JNK-mitogen-activated protein kinase (MAPK). Interestingly, deferasirox treatment significantly diminished the phosphorylation of all three MAPK subfamilies. These results suggest that deferasirox may confer a cardioprotective effect against iron induced injury. Am. J. Hematol. 2009. © 2009 Wiley-Liss, Inc. [source] Lead in soil by field-portable x-ray fluorescence spectrometry,an examination of paired In Situ and laboratory ICP-AES resultsREMEDIATION, Issue 3 2008David A. Binstock A major aspect of lead hazard control is the evaluation of soil lead hazards around housing coated with lead-based paint. The use of field-portable X-ray fluorescence (FPXRF) to do detailed surveying, with limited laboratory confirmation, can provide lead measurements in soil (especially for planning abatement activities) in a far more cost-efficient and timely manner than laboratory analysis. To date, one obstacle to the acceptance of FPXRF as an approved method of measuring lead in soil has been a lack of correspondence between field and laboratory results. In order to minimize the differences between field and laboratory results, RTI International (RTI) has developed a new protocol for field drying and sieving soil samples for field measurement by FPXRF. To evaluate this new protocol, composite samples were collected in the field following both U.S. Department of Housing and Urban Development (HUD) guidelines and ASTM International (ASTM) protocols, measured after drying by FPXRF, and returned to the laboratory for confirmatory inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis. Evaluation of study data from several diverse sites revealed no statistical difference between paired FPXRF and ICP-AES measurements using the new method. © 2008 Wiley Periodicals, Inc. [source] Identification of [(GS)2AsSe], in rabbit bile by size-exclusion chromatography and simultaneous multielement-specific detection by inductively coupled plasma atomic emission spectroscopyAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 2 2002Jürgen Gailer Abstract An arsenic,selenium metabolite that exhibited the same arsenic and selenium X-ray absorption near-edge spectra as the synthetic seleno-bis(S -glutathionyl) arsinium ion [(GS)2AsSe], was recently detected in rabbit bile within 25,min after intravenous injection of rabbits with sodium selenite and sodium arsenite. X-ray absorption spectroscopy did not (and cannot) conclusively identify the sulfur-donor in the in vivo sample. After similar treatment of rabbits, we analyzed the collected bile samples by size-exclusion chromatography (SEC) using inductively coupled plasma atomic emission spectroscopy (ICP-AES) to monitor arsenic, selenium and sulfur simultaneously. The bulk of arsenic and selenium eluted in a single peak, the intensity of which was greatly increased upon spiking of the bile samples with synthethic [(GS)2AsSe],. Hence, we identify [(GS)2AsSe], as the major metabolite in bile after exposure of rabbits to selenite and arsenite. The reported SEC,ICP-AES method is the first chromatographic procedure to identify this biochemically important metabolite in biological fluids and is thus a true alternative to X-ray absorption spectroscopy, which is not available to many chemists. Copyright © 2001 John Wiley & Sons, Ltd. [source] | |||||||||||||