Current Issue : January - March Volume : 2013 Issue Number : 1 Articles : 4 Articles
Chest x-rays (CXRs) are the main imaging tool in intensive care units (ICUs). CXRs also are associated with concerns\r\ninherent to their use, considering both healthcare organization and patient perspectives. In recent years, several\r\nstudies have focussed on the feasibility of lowering the number of bedside CXRs performed in the ICU. Such a\r\ndecrease may result from two independent and complementary processes: a raw reduction of CXRs due to the\r\nelimination of unnecessary investigations, and replacement of the CXR by an alternative technique. The goal of this\r\nreview is to outline emblematic examples corresponding to these two processes. The first part of the review\r\nconcerns the accumulation of evidence-based data for abandoning daily routine CXRs in mechanically ventilated\r\npatients and adopting an on-demand prescription strategy. The second part of the review addresses the use of\r\nalternative techniques to CXRs. This part begins with the presentation of ultrasonography or capnography\r\ncombined with epigastric auscultation for ensuring the correct position of enteral feeding tubes. Ultrasonography\r\nis then also presented as an alternative to CXR for diagnosing and monitoring pneumothoraces, as well as a\r\nvaluable post-procedural technique after central venous catheter insertion. The combination of the emblematic\r\nexamples presented in this review supports an integrated global approach for decreasing the number of CXRs\r\nordered in the ICU....
Background. A well-documented source of mercury contamination is skin-whitening cream.\r\nThe heavy metal is sometimes added to the cream to block production of melanin. Past\r\nstudies have shown that about one third of skin whitening creams for sale in Phnom Penh\r\ncontained mercury levels considerably higher than both United States and Association of\r\nSoutheast Asian Nations (ASEAN) guidelines. Developing nations such as Cambodia do not\r\nhave the resources for monitoring and enforcement.\r\nObjectives. Evaluate the utility of handheld X-ray fluorescence analyzers for detection of\r\nmercury in skin-whiteners.\r\nMethods. A handheld XRF unit was used to measure the total mercury content of 676 skinwhitening\r\ncreams collected from volunteers from a cross-section of Phnom Penh''s residents.\r\nResults. About 16% of bleaching creams collected contained more than 20 ug/g of mercury. The\r\nhighest concentration was about 35,000 ug/g. A third of the samples that were custom-made or\r\nmodified by beauty shops contained more than 20 ug/g of mercury.\r\nConclusions. The handheld XRF analyzer proved an excellent tool for screening mercury in\r\nskin creams, and could be particularly useful in developing countries because it is relatively\r\ninexpensive, requires no sample preparation or extraction, can be used by staff with little\r\ntechnical background, and can facilitate on-site education.\r\nCompeting Interests. The authors declare no competing financial interests....
Li2O2, Li2\r\nCO3, and Li2O are three critical compounds in lithium-air and lithium-ion energy storage systems. Extensive\r\nmeasurements have been carried out to study the chemical species and their evolutions at difference stages of the device\r\noperation. While x-ray spectroscopy has been demonstrated to be one of the most powerful tools for such purpose, no\r\nsystematic study on the irradiation effects have been reported. Here we carry out extensive time, position, and irradiation\r\ndependent Li K-edge soft x-ray absorption spectroscopy on these compounds with so far the best energy resolution. The\r\nultra-high resolution in the current study allows the features in the absorption spectra to be well-resolved. The spectral\r\nlineshape thus serves as the fingerprints of these compounds, enabling the tracking of their evolution under x-ray\r\nirradiation. We found that both Li2O2 and Li2CO3 evidently evolve towards Li2O under the soft x-ray irradiation with Li2CO3\r\nexhibiting a surprisingly higher sensitivity to x-rays than Li2O2. On the other hand, Li2O remains the most stable compound\r\ndespite experiencing substantial irradiation dose. We thus conclude that high resolution soft x-ray spectroscopy could\r\nunambiguously fingerprint different chemical species, but special cautions on irradiation effects would be needed in\r\nperforming the experiments and interpreting the data properly....
The neurotoxic effect of manganese (Mn) establishes itself in a condition known as manganism or Mn induced\r\nparkinsonism. While this condition was first diagnosed about 170 years ago, the mechanism of the neurotoxic action of Mn\r\nremains unknown. Moreover, the possibility that Mn exposure combined with other genetic and environmental factors can\r\ncontribute to the development of Parkinson�s disease has been discussed in the literature and several epidemiological\r\nstudies have demonstrated a correlation between Mn exposure and an elevated risk of Parkinson�s disease. Here, we\r\nintroduce X-ray fluorescence imaging as a new quantitative tool for analysis of the Mn distribution in the brain with high\r\nspatial resolution. The animal model employed mimics deficits observed in affected human subjects. The obtained maps of\r\nMn distribution in the brain demonstrate the highest Mn content in the globus pallidus, the thalamus, and the substantia\r\nnigra pars compacta. To test the hypothesis that Mn transport into/distribution within brain cells mimics that of other\r\nbiologically relevant metal ions, such as iron, copper, or zinc, their distributions were compared. It was demonstrated that\r\nthe Mn distribution does not follow the distributions of any of these metals in the brain. The majority of Mn in the brain was\r\nshown to occur in the mobile state, confirming the relevance of the chelation therapy currently used to treat Mn\r\nintoxication. In cells with accumulated Mn, it can cause neurotoxic action by affecting the mitochondrial respiratory chain.\r\nThis can result in increased susceptibility of the neurons of the globus pallidus, thalamus, and substantia nigra pars\r\ncompacta to various environmental or genetic insults. The obtained data is the first demonstration of Mn accumulation in\r\nthe substantia nigra pars compacta, and thus, can represent a link between Mn exposure and its potential effects for\r\ndevelopment of Parkinson�s disease....
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