The local anesthetic systemic toxicity can be due to increased blood lignocaine levels or due to increased sensitivity to lignocaine. Several cases of lignocaine-induced central nervous system toxicity have been noted, but none have reported only loss of consciousness without any seizure-like activity. Intravenous lipid emulsion administration for the treatment of local anesthetic systemic toxicity is an emerging topic of discussion, and there are case reports where they had successfully been used.
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Παρασκευή 11 Νοεμβρίου 2016
Unusual presentation of local anesthetic toxicity
Veterans Day message from Acadian Ambulance CEO
Acadian Ambulance CEO Richard Zuschlag thanked veterans for their service.
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Go and no-go P3 with rare and frequent stimuli in oddball tasks: A study comparing key-pressing with counting
Source:International Journal of Psychophysiology
Author(s): Rolf Verleger, Niels Grauhan, Kamila Śmigasiewicz
The P3 component of event-related potentials (ERPs) is large at posterior scalp sites with rare go stimuli (go-P3) and at anterior sites with rare no-go stimuli (no-go P3). Most hypotheses on P3, including our S-R link reactivation notion, imply that these characteristics are independent of specific response modes. This assumption was here investigated by comparing ERPs between key-pressing and covert counting responses in oddball tasks that required responses to either frequent or rare stimuli. Replicating previous results, topographic differences between parietal rare go-P3 and fronto-central rare no-go P3 were much reduced with counting compared to key-press responses. Besides, while go-P3 was generally more positive than no-go P3 in the key-press tasks (except for fronto-central no-go P3 with rare stimuli) the reverse was true in the counting tasks. Thus, the characteristic posterior and fronto-central go and no-go topographies appear to be specific to hand movements. Moreover, P3s evoked in counting tasks might not simply be P3 proper, uncontaminated by movement-related potentials, but rather the go/no-go logic might differ between counting and key-pressing, with the oddball effects being affected by specific processes implemented for these particular response modes.
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Measuring radon-222 in soil gas with high spatial and temporal resolution
Publication date: Available online 11 November 2016
Source:Journal of Environmental Radioactivity
Author(s): Darren Huxtable, David Read, George Shaw
In order to exploit 222Rn as a naturally-occurring tracer in soils we need to sample and measure radon isotopes in soil gas with high spatial and temporal resolution, without disturbing in situ activity concentrations and fluxes. Minimisation of sample volume is key to improving the resolution with which soil gas can be sampled; an analytical method is then needed which can measure radon with appropriate detection limits and precision for soil gas tracer studies. We have designed a soil gas probe with minimal internal dead volume to allow us to sample soil gas volumes of 45 cm3. Radon-222 is extracted from these samples into a mineral oil-based scintillation cocktail before counting on a conventional liquid scintillation counter. A detection limit of 320 Bq m−3 (in soil gas) is achievable with a 1 h count. This could be further reduced but, in practice, is sufficient for our purpose since 222Rn in soil gas typically ranges from 2000–50,000 Bq m−3. The method is simple and provides several advantages over commonly used field-portable instruments, including smaller sample volumes, speed of deployment and reliability under field conditions. The major limitation is the need to count samples in a liquid scintillation counter within 2–3 days of collection, due to the short (3.824 day) radioactive half-life of 222Rn. The method is not applicable to the very short-lived (55 s half-life) 220Rn.
Graphical abstract
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Tracing the source of sedimentary organic carbon in the Loess Plateau of China: An integrated elemental ratio, stable carbon signatures, and radioactive isotopes approach
Publication date: Available online 11 November 2016
Source:Journal of Environmental Radioactivity
Author(s): Chun Liu, Yuting Dong, Zhongwu Li, Xiaofeng Chang, Xiaodong Nie, Lin Liu, Haibing Xiao, Hassan Bashir
Soil erosion, which will induce the redistribution of soil and associated soil organic carbon (SOC) on the Earth's surface, is of critically importance for biogeochemical cycling of essential elements and terrestrial carbon sequestration. Despite the importance of soil erosion, surprisingly few studies have evaluated the sources of eroded carbon (C). This study used natural abundance levels of the stable isotope signature (13C) and radioactive isotopes (137Cs and 210Pbex), along with elements ratio (C/N) based on a two end member mixing model to qualitatively and quantitatively identify the sources of sedimentary OC retained by check dam in the Qiaozigou small watershed in the Loess Plateau, China. Sediment profiles (0–200 cm) captured at natural depositional area of the basin was compared to possible source materials, which included: superficial Loess mineral soils (0–20 cm) from three land use types [i.e., grassland (Medicago sativa), forestland (Robinia pseudoacacia.), shrubland (Prunus sibirica), and gully land (Loess parent material.)]. The results demonstrated that SOC in sediments showed significantly negative correlation with pH (P < 0.01), and positive correlation with soil water content (SWC) (P < 0.05). The sedimentary OC was not derived from grasslands or gullies. Forestland and shrubland were two main sources of eroded organic carbon within the surface sediment (0–60 cm deep), except for that in the 20–40 cm soil layer. Radionuclides analyses also implied that the surface sediments retained by check-dams mainly originated from soils of forestland and shrubland. Results of the two end-member mixing model demonstrated that more than 50% SOC (mean probability estimate (MPE) 50.13% via 13C and 60.53% via C/N) in surface sediment (0–20 cm deep) derived from forestland, whereas subsurface sedimentary SOC (20–200 cm) mainly resulted from shrubland (MPE > 50%). Although uncertainties on the sources of SOC in deep soils exist, the soil organic δ13C and C/N is still an effective indicator for sources of sedimentary organic carbon in the deposition zone in the short term (<10 years).
Graphical abstract
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Radioprotective effect of Zamzam (alkaline) water: A cytogenetic study
Source:Journal of Environmental Radioactivity
Author(s): Fatemeh Keramati Yazdi, Ali Shabestani Monfared, Hamed Tashakkorian, Aziz Mahmoudzadeh, Sajad Borzoueisileh
BackgroundRadioprotectors are useful compounds to reduce radiation toxicity of normal cells. Many natural radioprotectors have antioxidant power and display fewer toxicity and side effects than the chemical ones. Alkaline waters such as Zamzam have antioxidant power potentially. This study aimed to investigate the radioprotective effect of Zamzam water in mice bone marrow exposed to gamma radiation by micronuclei test.MethodFive study groups including control group which was fed by ordinary water, the second group was fed by Zamzam water, and radiation groups were received 2Gy gamma with ordinary and Zamzam water for 10 days and another for 20 days. The frequency of micronuclei and polychromatic erythrocytes to normochromatic erythrocytes ratio were calculated by micronuclei test.ResultIn the absence of radiation, no significant difference was found between Zamzam group and control in the number of micronuclei in normochromatic erythrocytes, micronuclei in polychromatic erythrocytes, and the polychromatic erythrocyte to polychromatic erythrocyte plus normochromatic erythrocyte ratio. But all of these indices were significantly different between irradiated and non-irradiated groups. The frequency of micronuclei in polychromatic erythrocytes was not significantly different between 10 and 20 days Zamzam irradiated groups, but the reduction in micronuclei in normochromatic erythrocytes and an increase in the polychromatic erythrocyte to polychromatic erythrocyte plus normochromatic erythrocyte ratio compared to ordinary water were seen in 20 days Zamzam group. Dose reduction factor was 1.36 and 2 for Zamzam water groups of 10 days and 20 days, respectively.ConclusionThe results demonstrated that Zamzam alkaline water could reduce clastogenic and cytotoxic effects of gamma irradiation.
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Improving transfer functions to describe radiocesium wash-off fluxes for the Niida River by a Bayesian approach
Source:Journal of Environmental Radioactivity
Author(s): M. Delmas, L. Garcia-Sanchez, V. Nicoulaud-Gouin, Y. Onda
This paper proposed methodological refinements of the generic transfer function approach to reconstruct radiocesium wash-off fluxes from contaminated catchments, by the integration of hydrological descriptors (passed volume of water, flow rate fluctuations and antecedent flow conditions). The approach was applied to the Niida River (Fukushima prefecture, Japan) for the period 03/2011-03/2015, for which daily flow rate (m3/s) and infrequent total radiocesium concentration (Bq/L) values were available from literature.Three models were defined, generic TF (Φ0), flow-corrected time variant (Φ1) and antecedent-flow corrected variant (Φ2). Calibration of these models' parameters was performed with a Bayesian approach because it is particularly adapted to limited datasets and censored information, and it provides parameters distributions.The model selection showed strong evidence of model Φ2 (indicated by marginal likelihood), which integrates current and recent hydrology in its formulation, and lower prediction errors (indicated by RMSE and ME). Models Φ1 and Φ2 better described wash-off dynamics compared to model Φ0, due to the inclusion of one or several hydrological descriptors.From March 2011 to March 2015, model Φ2 estimated 137Cs export from Niida catchment between 0.32 and 0.67 TBq, with a median value of 0.49 TBq, which represents around 0.27% of the initial fallout and could represent a significant source-term to the Ocean compared to the direct release from Fukushima Dai-ichi Nuclear Power Plant (FDNPP). Moreover the remaining 99% of the initial radiocesium fallout within the catchment may constitute a persistent contamination source for wash-off.Although the proposed methodology brought improvements in the assessment of wash-off fluxes, it remains an empirical interpolation method with a limited predictive power, particularly for recent low activities. To improve predictions, modelling approaches require more observed data (particularly more activity values corresponding to more hydrological conditions), and the inclusion of more hydrological descriptors.
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