Engineered carbon nanostructures, such as multiwalled carbon nanotubes (MWNTs), are inherently hydrophobic and are not readily stable in aqueous media. However, the aqueous stability and bioavailability of these nanotubes may be influenced by the water quality parameters such as ionic strength, pH, and natural organic matter (NOM). Natural organic matter adsorbs onto the surface of MWNTs, effectively covering the hydrophobic surface and resulting in increased aqueous stability. This enhanced stability is likely to lead to an increased residence time in the water column and increased exposure times for pelagic organisms. In the current study, NOM from three different river systems in the southeast United States increased the stability of MWNT suspensions. The effects of these suspensions were evaluated using acute and chronic bioassays with Daphnia magna and Ceriodaphnia dubia. The 96-h LC50 for D. magna exposed to MWNTs suspended in Suwannee River (USA) NOM was approximately 2.0 mg/L and was not significantly influenced by NOM concentrations ranging from 1.79 to 18.5 mg/L DOC. However, there were differences in 96-h LC50 values among different sources of NOM (Suwannee, Black, and Edisto Rivers, USA). Daphnid growth was reduced in both D. magna and C. dubia, whereas reproduction was reduced in C. dubia. Characterization of the different NOM sources and MWNT suspensions was conducted. Visual inspection using transmission electron microscopy (TEM) and gut elimination observations suggested that the toxicity was attributable to ingested MWNTs clogging the gut tract of D. magna. The TEM micrographs indicated that MWNTs can disaggregate within the gut tract, but single MWNTs are unable to absorb across the gut lumen.
In this experimental analysis, the effects of outcome feedback on risk propensity were assessed within the multiple-cue-probability-learning-paradigm (MCPLP). The individual decision maker in this taskDecision makers have to make decisions which can be characterized by uncertainty, incomplete information, complexity, novelty, iteration, and the use of judgment (e.g., Taylor, 1987). Decision making in uncertain environments, without complete information about relevant variables and the relationships among these variables, has been a topic of research in the study of strategic decision making (Ungson, Braunstein & Hall, 1981). For some time, the Brunswik (1955) lens model has been promoted for examining this and other related issues (e.g., Cosier, 1978; Taylor, Cosier & Ganster, 1979). In a laboratory setting (e.g., Cosier, 1978), this perspective has provided insight into decision-making processes and the effects of variables on decision outcomes (Schwenk, 1982).The Brunswik lens model is a paradigm with broad applications to the study of decision making. Since its introduction nearly forty years ago, the lens model has been the basis for hundreds of scientific studies examining a multitude of decision-making variables. The lens model assumes that there are three basic elements in a decision-making event: a decision maker, information, and a decision criterion.
Electronic patient-reported outcomes (ePROs) are effective tools for collecting health information and managing chronic conditions such as type 2 diabetes mellitus (T2DM). 1 Hypoglycemic agents including sulfonylureas and insulin carry a significant risk for hypoglycemia. 2,3 Hypoglycemia (blood glucose [BG] ≤70 mg/dl) increases the risk of cardiovascular and cerebrovascular events, and negatively impacts quality of life. 4,5 We conducted a pilot in T2DM patients new to sulfonylureas and/or insulin to compare the reporting of hypoglycemia events between in-clinic paper surveys and the secure web-based EmpiraMed™ PRO Portal™ (Portal) Platform (EmpiraMed, Inc, Maynard, MA). This was a six-month, US prospective observational study, approved by the Institutional Review Board at Lahey Hospital and Medical Center (LHMC) in Burlington, Massachusetts. The objectives were to 730379D STXXX10.
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