6,855 research outputs found
Increasing Student-Teacher Interactions at an Urban Commuter Campus through Instant Messaging and Online Office Hours
Encouraging first year undergraduate students in large lecture-hall classes to seek out and actively engage their professors is a perennial problem in science education. This problem is especially acute for commuter and minority populations. Thus, because personal relationships between students and professors are well known to promote student learning and academic success, fostering new ways to connect students and faculty is essential for reducing attrition at inner-city colleges. In the current study, we demonstrate that the use of instant messaging (IM) is highly effective in fostering student-teacher interactions in the lecture-hall setting of an introductory major-level biology course at John Jay College of Criminal Justice, a senior college within The City University of New York. We found that not only did the use of IM allow more students to directly contact their professors through the internet, but also formed the basis for a personal relationship, leading to increased in-person interaction during office hours. This argues that new internet-based communication technologies can help break down barriers between students and professors at the undergraduate level. We also discuss some of the further enhancements that are possible given these preliminary successes with IM. Clearly, increased use and development of Instant Messaging can play a vital role in the active engagement of students in the learning process
A novel combinatorial technique for simultaneous quantification of oxygen radicals and aggregation reveals unexpected redox patterns in the activation of platelets by different physiopathological stimuli
This is the author accepted manuscript. The final version is available fromFerrata Storti Foundation via the DOI in this recordThe regulation of platelets by oxidants is critical for vascular health and may explain thrombotic complications in diseases such as diabetes and dementia, but remains poorly understood. Here, we describe a novel technique combining electron paramagnetic resonance spectroscopy and turbidimetry, which has been utilised to monitor simultaneously platelet activation and oxygen radical generation. This technique has been used to investigate the redox-dependence of human and mouse platelets. Using selective peptide inhibitors of NOXs on human platelets and genetically modified mouse platelets (NOX1-/- or NOX2-/-), we discovered that:1) intracellular but not extracellular superoxide anion generated by NADPH oxidases (NOXs) is critical for platelet activation by collagen; 2) superoxide dismutation to hydrogen peroxide is required for thrombin-dependent activation; 3) NOX1 is the main source of oxygen radicals in response to collagen, while NOX2 is critical for activation by thrombin; 4) two platelet modulators, namely oxidised low density lipoproteins (oxLDL) and amyloid peptide β (Aβ), require activation of both NOX1 and NOX2 to pre-activate platelets. This study provides new insights on the redox dependence of platelet activation. It suggests the possibility of selectively inhibiting platelet agonists by targeting either NOX1 (for collagen) or NOX2 (for thrombin). Selective inhibition of either NOX1 or NOX2 impairs the potentiatory effect of tested platelet modulators (oxLDL and Aβ), but does not completely abolish platelet haemostatic function. This information offers new opportunities for the development of disease specific antiplatelet drugs with limited bleeding side effects by selectively targeting one NOX isoenzyme.British Heart Foundatio
Anaerobic Methane Oxidation in a Landfill-Leachate Plume
The alluvial aquifer adjacent to Norman Landfill, OK, provides an excellent natural laboratory for the study of anaerobic processes impacting landfill-leachate contaminated aquifers. We collected groundwaters from a transect of seven multilevel wells ranging in depth from 1.3 to 11 m that were oriented parallel to the flow path. The center of the leachate plume was characterized by (1) high alkalinity and elevated concentrations of total dissolved organic carbon, reduced iron, and methane, and (2) negligible oxygen, nitrate, and sulfate concentrations. Methane concentrations and stable carbon isotope (δ13C) values suggest anaerobic methane oxidation was occurring within the plume and at its margins. Methane δ13C values increased from about -54‰ near the source to >-10‰ downgradient and at the plume margins. The isotopic fractionation associated with this methane oxidation was -13.6±1.0‰. Methane 13C enrichment indicated that 80-90% of the original landfill methane was oxidized over the 210-m transect. Firstorder rate constants ranged from 0.06 to 0.23 per year, and oxidation rates ranged from 18 to 230µM/y. Overall, hydrochemical data suggest that a sulfate reducermethanogen consortium may mediate this methane oxidation. These results demonstrate that natural attenuation through anaerobic methane oxidation can be an important sink for landfill methane in aquifer systems
Risk screening for exposure to groundwater pollution in a wastewater irrigation district of the Mexico City region.
Untreated wastewater from the Mexico City basin has been used for decades to irrigate cropland in the Mezquital Valley, State of Hidalgo, Mexico. Excess irrigation water recharges the near-surface aquifer that is used as a domestic water supply source. We assessed the groundwater quality of three key groundwater sources of domestic water by analyzing for 24 trace metals, 67 target base/neutral/acid (BNA) organic compounds, nontarget BNA organics, 23 chlorinated pesticides, 20 polychlorinated biphenyls, and nitrate, as well as microbiological contaminants--coliforms, Vibrio cholerae, and Salmonella. Study participants answered a questionnaire that estimated ingestion and dermal exposure to groundwater; 10% of the sample reported frequent diarrhea and 9% reported persistent skin irritations. Detection of V. cholerae non-01 in surface waters at all sites suggested a potential risk (surrogate indicator present) of diarrheal disease for canal and river bathers by accidental ingestion, as well as potential Vibrio contamination of near-surface groundwater and potential cholera risk, magnified by lapses in disinfection. High total coliform levels in surface water and lower levels in groundwater at all sites indicated fecal contamination and a potential risk of gastrointestinal disease in populations exposed to inadequately disinfected groundwater. Using chemical criteria, no significant risk from ingestion or dermal contact was identified at the method detection limits at any site, except from nitrate exposure: infants and young children are at risk from methemoglobinemia at all sites. Results suggest that pathogen risk interventions are a priority, whereas nitrate risk needs further characterization to determine if formal treatment is needed. The risks exist inside and outside the irrigation district. The method was highly cost-effective
Manufacturing of Annular Targets Made of LEU Foil Coated with Electrodeposited Nickel
AbstractThe results achieved in the development of an annular target manufacturing technology for Mo-99 radioisotope production, with targets containing a low enriched uranium LEU foil, are presented in this paper. The paper describes the annular targets manufacture comprising the uranium foil and a thin layer of nickel obtained by electroplating on the surface of the uranium, resulting in Ni deposits with thickness of 15 to 25 microns. It was necessary to determine the potential to avoid the presence of uranium oxide and also to determine the intensity (amperage) at which its formation begins. The results obtained, showed that the mass of Ni deposited on the uranium foil is proportional to the electroplating time and the current intensity. Ultrasonic Tests and Screen Electronic Microscopy revealed good bonding and homogeneity of the nickel deposit. The Ni layer had a high hardness and a relatively small grain size with an orientation in the direction of the electrical current flow
Ventilator-associated Pneumonia After Elective Cardiac Surgery Caused by Pneumocystis Jirovecii
Ventilator-associated pneumonia is a severe complication among patients undergoing cardiac
surgery. Although hospital-acquired bacterial pathogens, often multidrug resistant, are the most
frequent cause, non-bacterial atypical and opportunistic agents traditionally associated with
immunocompromise are increasingly recognized. We describe ventilator-associated pneumonia
due to Pneumocystis jirovecii in the absence of traditional risk factors for Pneumocystis
pneumonia in a patient after cardiac surgery
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