Assessment of the concentration of Cr, Mn and Fe in sediment using laser-induced breakdown spectroscopy

In the present study, laser-induced breakdown spectroscopy (LIBS) has been applied for the determination of levels of Cr, Mn and Fe in sediment samples and the results have been compared with that of flame-atomic absorption spectroscopy (F-AAS). Fourteen sediment samples were collected from Tinishu Akaki River (TAR), Addis Ababa, Ethiopia. Pellets of 24 mm in diameter and 3-5 mm in thickness were prepared using a manual hydraulic press under a pressure of 8000 psi by mixing finely ground sediment samples with boric acid. The concentrations of Cr, Mn and Fe were successfully determined by Q-switched Nd:YAG laser at 1064 nm. Quantification of these metals was conducted against certified reference materials of sediments and soils. The LIBS results for the elements varied from 0.060–0.707 mg/g for Cr, 0.895–3.64 mg/g for Mn and 26.9–71.8 mg/g for Fe. The F-AAS results varied from 0.061–1.37 mg/g for Cr, 1.24–4.46 mg/g for Mn and 49.0–83.3 mg/g for Fe. TAR was found to be heavily polluted with Cr. KEY WORDS: Laser-induced breakdown spectroscopy, Chromium, Manganese, Iron, Sediment, Tinishu Akaki River, Ethiopia Bull. Chem. Soc. Ethiop. 2013, 27(1), 1-13.DOI: http://dx.doi.org/10.4314/bcse.v27i1.

Non-invasive MR imaging techniques for measuring femoral arterial flow in a pediatric and adolescent cohort

This is the final version. Available on open access from Wiley via the DOI in this recordMagnetic Resonance Imaging (MRI) is well-suited for imaging peripheral blood flow due to its non-invasive nature and excellent spatial resolution. Although MRI is routinely used in adults to assess physiological changes in chronic diseases, there are currently no MRI-based data quantifying arterial flow in pediatric or adolescent populations during exercise. Therefore the current research sought to document femoral arterial blood flow at rest and following exercise in a pediatric-adolescent population using phase contrast MRI, and to present test-retest reliability data for this method. Ten healthy children and adolescents (4 male; mean age 14.8 ± 2.4 years) completed bloodwork and resting and exercise MRI. Baseline images consisted of PC-MRI of the femoral artery at rest and following a 5 × 30 s of in-magnet exercise. To evaluate test-retest reliability, five participants returned for repeat testing. All participants successfully completed exercise testing in the MRI. Baseline flow demonstrated excellent reliability (ICC = 0.93, p = 0.006), and peak exercise and delta rest-peak flow demonstrated good reliability (peak exercise ICC = 0.89, p = 0.002, delta rest-peak ICC = 0.87, p = 0.003) between-visits. All three flow measurements demonstrated excellent reliability when assessed with coefficients of variance (CV's) (rest: CV = 6.2%; peak exercise: CV = 7.3%; delta rest-peak: CV = 7.1%). The mean bias was small for femoral arterial flow. There was no significant mean bias between femoral artery flow visits 1 and 2 at peak exercise. There were no correlations between age or height and any of the flow measurements. There were no significant differences between male and female participants for any of the flow measurements. The current study determined that peripheral arterial blood flow in children and adolescents can be evaluated using non-invasive phase contrast MRI. The MRI-based techniques that were used in the current study for measuring arterial flow in pediatric and adolescent patients demonstrated acceptable test-retest reliability both at rest and immediately post-exercise.Cystic Fibrosis TrustExercise Medicine Fund at the Hospital for Sick Children (Canada

A compilation of field surveys on gaseous elemental mercury (GEM) from contrasting environmental settings in Europe, South America, South Africa and China: separating fads from facts

Mercury is transported globally in the atmosphere mostly in gaseous elemental form (GEM, Hg0 gas), but still few worldwide studies taking into account different and contrasted environmental settings are available in a single publication. This work presents and discusses data from Argentina, Bolivia, Bosnia and Herzegovina, Brazil, Chile, China, Croatia, Finland, Italy, Russia, South Africa, Spain, Slovenia and Venezuela. We classified the information in four groups: (1) mining districts where this contaminant poses or has posed a risk for human populations and/or ecosystems; (2) cities, where the concentration ofatmospheric mercury could be higher than normal due to the burning of fossil fuels and industrial activities; (3) areas with natural emissions from volcanoes; and (4) pristine areas where no anthropogenic influence was apparent. All the surveys were performed using portable LUMEX RA-915 series atomic absorption spectrometers. The results for cities fall within a low GEM concentration range that rarely exceeds 30 ng m-3, that is, 6.6 times lower than the restrictive ATSDR threshold (200 ng m-3) for chronic exposure to this pollutant. We also observed this behavior in the former mercury mining districts, where few data were above 200 ng m-3.We noted that high concentrations of GEM are localized phenomena that fade away in short distances. However, this does not imply that they do not pose a risk for those working in close proximity to the source. This is the case of the artisanal gold miners that heat the Au–Hg amalgam to vaporize mercury. In this respect, while GEM can be truly regarded as a hazard, because of possible physical–chemical transformations into other species, it is only under these localized conditions, implying exposure to high GEM concentrations, which it becomes a direct risk for humans.Grants CGL2009-13171 and CTM2012-33918 from the Spanish Ministry of Economy and Competitiveness and PII1I09-0142- 4389 from theCastilla-LaMancha (Spain)RegionalGovernment.Published713-7346A. Monitoraggio ambientale, sicurezza e territorioJCR Journalrestricte

Adventure revisited:Critically examining the concept of adventure and its relations with contemporary outdoor education and learning

Editorial piece on the impact of mobile technology in a post-Mortlockian era of adventure

Shell MIddens of the Coast of Balochistan

Summary paper on the prehistoric shell middens of the coast of Las bela in Balochistan and southern Sindh (Pakistan

Effect of garlic on blood pressure: A systematic review and meta-analysis

The electronic version of this article is the complete one and can be found online at the publisher's website.Background: Non-pharmacological treatment options for hypertension have the potential to reduce the risk of cardiovascular disease at a population level. Animal studies have suggested that garlic reduces blood pressure, but primary studies in humans and non-systematic reviews have reported mixed results. With interest in complementary medicine for hypertension increasing, it is timely to update a systematic review and meta-analysis from 1994 of studies investigating the effect of garlic preparations on blood pressure. Methods: We searched the Medline and Embase databases for studies published between 1955 and October 2007. Randomised controlled trials with true placebo groups, using garlic-only preparations, and reporting mean systolic and/or diastolic blood pressure (SBP/DBP) and standard deviations were included in the meta-analysis. We also conducted subgroup meta-analysis by baseline blood pressure (hypertensive/normotensive), for the first time. Meta-regression analysis was performed to test the associations between blood pressure outcomes and duration of treatment, dosage, and blood pressure at start of treatment. Results: Eleven of 25 studies included in the systematic review were suitable for meta-analysis. Meta-analysis of all studies showed a mean decrease of 4.6 ± 2.8 mm Hg for SBP in the garlic group compared to placebo (n = 10; p = 0.001), while the mean decrease in the hypertensive subgroup was 8.4 ± 2.8 mm Hg for SBP (n = 4; p < 0.001), and 7.3 ± 1.5 mm Hg for DBP (n = 3; p < 0.001). Regression analysis revealed a significant association between blood pressure at the start of the intervention and the level of blood pressure reduction (SBP: R = 0.057; p = 0.03; DBP: R = -0.315; p = 0.02). Conclusion: Our meta-analysis suggests that garlic preparations are superior to placebo in reducing blood pressure in individuals with hypertension.Karin Ried, Oliver R. Frank, Nigel P. Stocks, Peter Fakler and Thomas Sulliva