Fluorine toxicity studies Status progress report

Fluorine toxicity studies of effects from human inhalation and damage to animal kidney

Report of Toxic Effects of Fluorine Following Short-Term Inhalation

Toxic effects of fluorine following short term inhalation by animals and human

Constructing and deconstructing bias: modeling privilege and mentorship in agent-based simulations

Bias exists in how we pick leaders, who we perceive as being influential, and who we interact with, not only in society, but in organizational contexts. Drawing from leadership emergence and social influence theories, we investigate potential interventions that support diverse leaders. Using agent-based simulations, we model a collective search process on a fitness landscape. Agents combine individual and social learning, and are represented as a feature vector blending relevant (e.g., individual learning characteristics) and irrelevant (e.g., race or gender) features. Agents use rational principles of learning to estimate feature weights on the basis of performance predictions, which are used to dynamically define social influence in their network. We show how biases arise based on historic privilege, but can be drastically reduced through the use of an intervention (e.g. mentorship). This work provides important insights into the cognitive mechanisms underlying bias construction and deconstruction, while pointing towards real-world interventions to be tested in future empirical work

Non-destructive detection of cross-sectional strain and defect structure in an individual Ag five-fold twinned nanowire by 3D electron diffraction mapping

Coherent x-ray diffraction investigations on Ag five-fold twinned nanowires (FTNWs) have drawn controversial conclusions concerning whether the intrinsic 7.35° angular gap could be compensated homogeneously through phase transformation or inhomogeneously by forming disclination strain field. In those studies, the x-ray techniques only provided an ensemble average of the structural information from all the Ag nanowires. Here, using three-dimensional (3D) electron diffraction mapping approach, we non-destructively explore the cross-sectional strain and the related strain-relief defect structures of an individual Ag FTNW with diameter about 30 nm. The quantitative analysis of the fine structure of intensity distribution combining with kinematic electron diffraction simulation confirms that for such a Ag FTNW, the intrinsic 7.35° angular deficiency results in an inhomogeneous strain field within each single crystalline segment consistent with the disclination model of stress-relief. Moreover, the five crystalline segments are found to be strained differently. Modeling analysis in combination with system energy calculation further indicates that the elastic strain energy within some crystalline segments, could be partially relieved by the creation of stacking fault layers near the twin boundaries. Our study demonstrates that 3D electron diffraction mapping is a powerful tool for the cross-sectional strain analysis of complex 1D nanostructures

Environmental occurrence, analysis, and toxicology of toxaphene compounds.

Toxaphene production, in quantities similar to those of polychlorinated biphenyls, has resulted in high toxaphene levels in fish from the Great Lakes and in Arctic marine mammals (up to 10 and 16 microg g-1 lipid). Because of the large variabiliity in total toxaphene data, few reliable conclusions can be drawn about trends or geographic differences in toxaphene concentrations. New developments in mass spectrometric detection using either negative chemical ionization or electron impact modes as well as in multidimensional gas chromatography recently have led researchers to suggest congener-specific approaches. Recently, several nomenclature systems have been developed for toxaphene compounds. Although all systems have specific advantages and limitations, it is suggested that an international body such as the International Union of Pure and Applied Chemistry make an attempt to obtain uniformity in the literature. Toxicologic information on individual chlorobornanes is scarce, but some reports have recently appeared. Neurotoxic effects of toxaphene exposure such as those on behavior and learning have been reported. Technical toxaphene and some individual congeners were found to be weakly estrogenic in in vitro test systems; no evidence for endocrine effects in vivo has been reported. In vitro studies show technical toxaphene and toxaphene congeners to be mutagenic. However, in vivo studies have not shown genotoxicity; therefore, a nongenotoxic mechanism is proposed. Nevertheless, toxaphene is believed to present a potential carcinogenic risk to humans. Until now, only Germany has established a legal tolerance level for toxaphene--0.1 mg kg-1 wet weight for fish

Supraclavicular ultrasound-guided catheterization of the brachiocephalic vein in infants and children: A retrospective analysis

Objective/Background: Ultrasound (US) facilitates central venous catheter (CVC) placement in children. A new supraclavicular approach using the brachiocephalic vein (BCV) for US-guided CVC placement in very small children has been recently described. In 2012, we changed our departmental standard and used the left BCV as preferred puncture site during CVC placement. In our retrospective analysis, we compared US-guided cannulation of the BCV with other puncture sites (control). Design/Materials and Methods: We performed a retrospective analysis of all CVC cannulations from October 2012 to October 2013 in our department. For cannulation of the BCV, the in-plane technique was used to guide the needle into the target vein. Results: We performed CVC cannulations in 106 children (age 1-day to 18 years). In 29 patients, the weight was <4.5 kg. CVC placement was successful in all patients. The left BCV could be used in 81.1% of all cases. In a Poisson regression model of punctures regressed by age, weight or group (left BCV vs. control), age, weight or the cannulation site did not influence the number of punctures. In a logistic regression model of complications (yes vs. no) regressed by the group (left brachiocephalic vs. control) an odds ratio of 0.15 was observed (95% confidence interval 0.03-0.72, P likelihood ratio test = 0.007). Conclusion: US-guided puncture of the left BCV is a safe method of CVC placement in children. The use of the left BCV was associated with a high success rate in our retrospective analysis