The influence of calcium and dissolved organic matter on the acute and chronic toxicity of nickel to Hyalella azteca

This study focuses on the effect of Ca and dissolved organic matter (DOM) on Ni toxicity to Hyalella azteca in soft waters (interpreted in the context of the biotic ligand model (BLM)) and is linked to a larger project directed at understanding the recovery of aquatic systems from long term smelter damage. Amphipods (source: Hannah Lake, Sudbury ON) were cultured and tested in soft waters (12 mg CaCO3/L, pH 7.0, 21ºC) following Environment Canada standard method EPS 1/RM/33 (Environment Canada, 1997). Effects of Ca, but not Mg, were observed where a 5-fold increase in protection was a result of an increase of Ca concentrations from 0.1 to 2.0 mM. DOM was collected from sites previously impacted and recovering from long term smelter emissions and also from reference sites in central Ontario. Dissolved organic carbon (DOC) concentrations at 6 mg/L and higher offered protection against Ni toxicity. Acute toxicity tests with different DOM sources (at 6 mg DOC/L) showed variation in protective capacity but no clear links to measured optical characteristics were observed. DOM sources also reduced short term (6h) whole body accumulation of Ni but there was no correlation between the capacity of DOM to reduce accumulation and its ability to mitigate toxicity. Application of the BLM illustrated that acute toxicity could be modelled reasonably well except for some effects of Ca (2.0mM). Chronic (28d) effects on Hyalella occurred at much lower Ni concentrations (acute to chronic ratio of approximately 50) and the protective effects of Ca and DOM were proportionally similar. For example, 1mM Ca increased the chronic LC50 by 3-fold. Growth (assessed as dry weight) was generally a more sensitive indicator of impacts than survival. In exposures without modifying factors, the EC20 and EC50 for growth were 1.4 and 12.7 µg Ni/L, respectively, while the LC50 was 13.8 (CI: 11.5 - 16.7) µg Ni/L. Contrary to other studies, this research did not show relationships between DOM quality and toxicity mitigation and this demonstrates the need for an improved understanding of DOM characteristics in relation to the potential impact of Ni

Improving access to training opportunities for women in precarious work

Precarious work is a growing form of employment associated with low-pay, job insecurity, income volatility, unsafe working conditions, and a lack of access to training opportunities among other conditions. These conditions are damaging for all who work in precarious employment and yet, research finds women are disproportionately represented in this type of work. As a result, women may be more likely to face socio-economic challenges in the short and long-term, including having limited access to training opportunities. Given the limited research on precarious workers’ abilities to access training opportunities, this study further explores this challenge while focusing on women. A series of policy options are analyzed and compared to provide a recommendation for how to improve access to training opportunities for women in precarious work

The minimal structure containing the band 3 anion transport site. A 35Cl NMR study

35Cl NMR, which enables observation of chloride binding to the anion transport site on band 3, is used in the present study to determine the minimal structure containing the intact transport site. Removal of cytoskeletal and other nonintegral membrane proteins, or removal of the 40-kDa cytoskeletal domain of band 3, each leave the transport site intact. Similarly, cleavage of the 52-kDa transport domain into 17- and 35-kDa fragments by chymotrypsin leaves the transport site intact. Extensive proteolysis by papain reduces the integral red cell membrane proteins to their transmembrane segments. Papain treatment removes approximately 60% of the extramembrane portion of the transport domain and produces small fragments primarily in the range 3-7 kDa, with 5 kDa being most predominant. Papain treatment damages, but does not destroy, chloride binding to the transport site; thus, the minimal structure containing the transport site is composed solely of transmembrane segments. In short, the results are completely consistent with a picture in which the transport site is buried in the membrane where it is protected from proteolysis; the transmembrane segments that surround the transport site are held together by strong attractive forces within the bilayer; and the transport site is accessed by solution chloride via an anion channel leading from the transport site to the solution

Adapting a Field-Deployable Noble Gas Mass Spectrometer for Continuous Measurements of Helium

Isotopes of the five stable noble gases (He, Ne, Ar, Kr, and Xe) are useful in analyzing physical processes in the environment such as air-sea gas exchange and sea ice formation and melting. Traditional measurements of noble gases are costly and time-consuming because of the need to transport water samples to analyze in a laboratory-based mass spectrometer. Field deployable mass spectrometers were developed as a low-cost method to increase the temporal resolution of the measurements. Our system utilizes a quadrupole mass spectrometer in tandem with a gas equilibrator cartridge to continuously measure equilibrated gases from water with ambient air as a calibration standard. The reproducibility of the system is better than 0.7% for all gas ratios in a lab environment. However, our current configuration is not optimized for measuring helium because of the high permeability of helium through many of the materials used. Nonetheless, measuring helium will yield insight into quantifying bubble processes, which significantly affects rates of air-sea gas exchange. Our mass spectrometer configuration was thus extended to measure helium by switching from fused silica capillaries to stainless steel capillaries and switching from Tygon tubing to Viton tubing. The equilibration and precision of the new system was compared to that of the old configuration. Leak tests were performed on the old and new configuration to assess whether the leakiness of the system has improved. Results showed effective measurements of He with precisions better than 0.80% for both He/Ar and He/Kr at water temperatures of 22°C and above. Further optimization is needed to improve the equilibration of He and Ne at water temperatures of 10°C

Hermeneutics in Primary Care: Corneal Ulceration Treated with Bandage Contact Lenses / Alternate title: Case Report - Corneal Ulceration Treated with Bandage Contact Lenses

Bandage contact lens use in primary care optometry can be important for allowing people to live without painful effects of corneal disease. This particular case study describes the initial healing of ulceration with a bandage contact lens inserted and also the long term issues of recurrence of ulceration with cessation of lens wear and management of microbial keratoconjunctivitis with bandage lens wear. In an attempt to address holistic themes this paper utilises a hermeneutical approach to clinical judgement in a primary care setting

Harnessing Change to Create Sustainable Growth; The Visitacion/ Guadalupe Valley

A Regional Perspective is a report authored by Visitacion Valley Community Development Corporation and Asian Neighborhood Design as the first steps in efforts to create a regional planning perspective, collecting and analyzing data to assist in planning efforts towards sustainable growth, building relationships between regional stakeholders and decision-makers, and providing community outreach to inform and encourage community participation

Sustainable development and high density living

Thesis (B.Sc)--University of Hong Kong, 2006.published_or_final_versio

“You Have to Know Your Body!”: The Role of the Body in Influencing the Information Behaviors of People with Type 2 Diabetes

Although many information behavior studies have investigated the wide array of sources people turn to when they have a health-related information need, very few have looked at the roles played by the body in these processes. Drawing on a mixed-method exploration of the information behaviors of people with type 2 diabetes, this study identifies the important roles played by an individual’s own body (i.e., informant, motivator, demotivator, and barrier) and by the bodies of other people with diabetes (i.e., comrades/mentors, role models, galvanizers, inhibitors, inspirations, and potential mentees). One of the most significant findings is that a person’s own body and the bodies of others with diabetes can fuel incognizance (an enduring unawareness that one has a particular information need), information avoidance, and information nonuse; however, they also can interrupt incognizance, illuminating information needs and motivating information seeking and use. We propose a novel model of body-related information behavior and discuss the possibility that body-related information behaviors may not only affect an individual’s health trajectory but also reinforce health disparities within disadvantaged communities. In conclusion, we recommend strategies for ensuring everyone has optimal opportunities to benefit from body-related information behaviors and to live a long and healthy life

Case-Based Asynchronous Interactive Modules in Undergraduate Medical Education.

Undergraduate medical education traditionally consists of 2 years of lecture-based courses followed by 2 years of clinical clerkships. However, over the past couple decades, undergraduate medical education has been evolving toward non-lecture-based integrated curriculums, requiring a collaborative curriculum. Additionally, e-learning platforms have become efficacious and essential to delivering education asynchronously to students. At Thomas Jefferson University, the Pathology and Obstetrics and Gynecology departments collaborated to create a pilot series of case-based asynchronous interactive modules to teach gynecologic pathology in a clinical context, while interweaving other educational components, such as evidence-based medicine, clinical skills, and basic sciences. The case-based asynchronous interactive modules were given to third-year medical students during their obstetrics and gynecology clerkship. Students interpreted histologic and clinical images while being evaluated on clinical management skills, gynecologic diagnoses, general principles of population health and pathology. Sixty-eight students from 3 blocks completed a pre and posttest. All participants showed improvement in interpreting gynecologic pathology in routine clinical scenarios as well as improved case-based decision-making, with an average score increase by 5.7%. Learner feedback was positive, with suggestions to apply this method to other medical specialties, particularly radiology. Asynchronous interactive modules are an efficacious and popular method of pathology education

Cost-effectiveness analysis of the management of distal ureteral stones in children

Objective To determine the most cost-effective approach to the management of distal ureteral stones in children given the potential for recurrent renal colic during a trial of passage versus potential stent discomfort and complications of ureteroscopy. Methods We developed a decision tree to project costs and clinical outcomes associated with observation, medical explusive therapy (MET), and ureteroscopy for the management of an index patient with a 4mm distal ureteral stone. We determined which strategy would be least costly and offer the most pain-free days within 30 days of diagnosis. We performed a one-way sensitivity analysis on the probability of successful stone passage with MET. We obtained probabilities from the literature and costs from the 2016 Pediatric Health Information System Database. Results Ureteroscopywas the costliest strategy but maximized the number of pain-free days within 30 days of diagnosis ($5,282/29 pain-free days). MET was less costly than ureteroscopybut also less effective ($615/21.8 pain-free days). Observation cost more than MET and was also less effective ($2,139/15.5 pain-free days). The one-way sensitivity analysis on the probability of successful stone passage with MET demonstrated that ureteroscopyalways has the highest net monetary benefits value and is therefore the recommended strategy given a fixed WTP. Discussion Using a rigorous decision-science approach, we found that ureteroscopy is the recommended strategy in children with small distal ureteral stones. Although it cost more than MET, it resulted in more pain-free days in the first 30 days following diagnosis given the faster resolution of the stone episode