Utilizing Service Learning in the Analytical Chemistry Classroom

Service learning has been incorporated into the Analytical Chemistry Laboratory to give students a real world sampling experience including both soil and water, alongside professionals in their fields. Analysis of the soil and water includes metals, suspended solids, phosphorus and nitrogen containing compounds requiring knowledge of several different instrumental and wet chemical techniques. Most educational experiences do not afford students the chance to see the real world applications of their classroom knowledge, but with the service learning aspects this deficiency has been resolved. In the soil experience, students provide homeowners from the Highland Park and South Wedge neighbors with lead analysis of their soil as well as written reports of those levels and information on removing or working with lead contaminated soil. For the water project, students are providing baseline analysis of nutrients and metals found in Buckland Creek for the Department of Environmental Services, Division of Pure Waters, which studies the effects of industrial expansion and human activity on water quality in Rochester. The analytical chemistry students further their experience in an advanced analytical chemistry course the following year by performing further analysis on the soil and water, but on a more independent level. They use their previous learned skills to gather water after rainfall and perform analysis back in the laboratory with no structured guidance. The class is also expanding to include a plant biology section, where students will test the affects on growth and safety of plants grown in leaded soil. This experiment will allow students to provide proof to homeowners as to which plants are healthy to eat and which can be used for phytoremediation. In addition to feeling like active contributors to the community, the students and homeowners have been interviewed and photographed for an article detailing lead contamination issues

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Design and Application of Microfluidic Platforms for Integrated Adipocyte Perfusion and Secretion Analysis by Enzyme Assay and Mass Spectrometry.

Microfluidic chips enable integration of many components onto one miniaturized platform, creating highly automated devices with the potential for increased throughput of chemical analysis processes. Chips can be adapted to load and perfuse cells; the continuous flow principle of these devices is more biomimetic to the in vivo cellular environment, and allows collection and analysis of secreted metabolites with greater temporal resolution. To learn more about their cellular function, polydimethyl siloxane (PDMS) microfluidic devices were developed to perfuse 3T3-L1 adipocytes and measure secreted lipolysis products. A chip was constructed that contained a cell perfusion chamber with integrated fluorescent enzyme assay reaction channels to simultaneously monitor adipocyte release of non-esterified fatty acids (NEFAs) and glycerol. This multiplexed analysis was measured with laser-induced fluorescence (LIF) detection. The NEFA assay had a limit of detection (LOD) of 6 µM and the glycerol assay had a LOD of 5 µM; both assays had sufficient linear dynamic ranges to measure the secreted products at a flow rate of 0.75 µL/min. Initial studies monitored the secretion of lipolysis products under basal and stimulated conditions. With simultaneous detection, NEFA recycling could be inferred, based on the ratio of secreted NEFAs to glycerol. Further studies compared on-line perfusion and analysis to conventional off-line techniques in terms of NEFA recycling; initial findings suggest there is less NEFA recycling with on-chip cell perfusion. Additionally, pilot studies investigated the kinetics of lipolysis regulation by applying brief pulses of chemical stimuli. A second chip was developed to couple on-line adipocyte perfusion with mass spectrometry (MS) detection to learn more about the identities of secreted NEFAs. As the enzyme assay only permits measurement of total NEFA concentration, MS allows multiplexed analyte detection. An injection loop was integrated downstream of a cell perfusion chamber, operated with multilayer pneumatically-actuated valves. The injection loop acted to isolate the cells from the back pressures generated from the solid phase extraction (SPE) bed coupled to the chip, which was necessary to improve electrospray ionization (ESI)-MS efficiency. Eight NEFAs secreted from adipocytes were monitored under basal and lipolysis-stimulated conditions using this chip.PHDChemistryUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/120739/1/cedugan_1.pd

Utilizing Service Learning in the Analytical Chemistry Classroom

Service learning has been incorporated into the Analytical Chemistry Laboratory to give students a real world sampling experience including both soil and water, alongside professionals in their fields. Analysis of the soil and water includes metals, suspended solids, phosphorus and nitrogen containing compounds requiring knowledge of several different instrumental and wet chemical techniques. Most educational experiences do not afford students the chance to see the real world applications of their classroom knowledge, but with the service learning aspects this deficiency has been resolved. In the soil experience, students provide homeowners from the Highland Park and South Wedge neighbors with lead analysis of their soil as well as written reports of those levels and information on removing or working with lead contaminated soil. For the water project, students are providing baseline analysis of nutrients and metals found in Buckland Creek for the Department of Environmental Services, Division of Pure Waters, which studies the effects of industrial expansion and human activity on water quality in Rochester. The analytical chemistry students further their experience in an advanced analytical chemistry course the following year by performing further analysis on the soil and water, but on a more independent level. They use their previous learned skills to gather water after rainfall and perform analysis back in the laboratory with no structured guidance. The class is also expanding to include a plant biology section, where students will test the affects on growth and safety of plants grown in leaded soil. This experiment will allow students to provide proof to homeowners as to which plants are healthy to eat and which can be used for phytoremediation. In addition to feeling like active contributors to the community, the students and homeowners have been interviewed and photographed for an article detailing lead contamination issues

Microfluidic Chip with Integrated Electrophoretic Immunoassay for Investigating Cell–Cell Interactions

Microfluidics have been used to create “body-on-chip” systems to mimic in vivo cellular interactions with a high level of control. Most such systems rely on optical observation of cells as a readout. In this work we integrated a cell–cell interaction chip with online microchip electrophoresis immunoassay to monitor the effects of the interaction on protein secretion dynamics. The system was used to investigate the effects of adipocytes on insulin secretion. Chips were loaded with 190 000 3T3-L1 adipocytes and a single islet of Langerhans in separate chambers. The chambers were perfused at 300–600 nL/min so that adipocyte secretions flowed over the islets for 3 h. Adipocytes produced 80 μM of nonesterified fatty acids (NEFAs), a factor known to impact insulin secretion, at the islets. After perfusion, islets were challenged with a step change in glucose from 3 to 11 mM while monitoring insulin secretion at 8 s intervals by online immunoassay. Adipocyte treatment augmented insulin secretion by 6-fold compared to controls. The effect was far greater than comparable concentrations of NEFA applied to the islets demonstrating that adipocytes release multiple factors that can strongly potentiate insulin secretion. The experiments reveal that integration of chemical analysis with cell–cell interaction can provide valuable insights into cellular functions

Hybrid millidecade spectra: A practical format for exchange of long-term ambient sound data

This Letter proposes a frequency scaling for processing, storing, and sharing high-bandwidth, passive acoustic spectral data that optimizes data volume while maintaining reasonable data resolution. The format is a hybrid that uses 1 Hz resolution up to 455 Hz and millidecade frequency bands above 455 Hz. This hybrid is appropriate for many types of soundscape analysis, including detecting different types of soundscapes and regulatory applications like computing weighted sound exposure levels. Hybrid millidecade files are compressed compared to the 1 Hz equivalent such that one research center could feasibly store data from hundreds of projects for sharing among researchers globally

Platelet factor-4 concentration in adult veno-arterial ECMO patients

Background: Heparin induced thrombocytopenia (HIT) is reported at a variable rate in extracorporeal membrane oxygenation (ECMO) patients. A critical factor impacting platelet factor-4 (PF4)-heparin antibody formation is plasma PF4 concentration. We hypothesized that PF4 concentration would be increased during veno-arterial (VA) ECMO. Methods: Plasma PF4 concentration was measured during the first 5 ECMO days in 20 VA ECMO patients and 10 control plasma samples. PF4-heparin ratios were estimated using an assumed heparin concentration of 0.4 IU/mL. This correlates with an activated partial thromboplastin time of 60 to 80 seconds, which is the anticoagulation target in our center. Results: Twenty VA ECMO patients were enrolled, 10 of which had pulmonary embolism. Median PF4 concentration was 0.03 µg/mL [0.01, 0.13] in control plasma. Median PF4 concentration was 0.21 µg/mL [0.12, 0.34] on ECMO day 1 or 2, 0.16 µg/mL [0.09, 0.25] on ECMO day 3, and 0.12 µg/mL [0.09, 0.22] on ECMO day 5. Estimated median PF4-heparin ratios were 0.04, 0.03, and 0.02 respectively. Two patients (10%) developed HIT that was confirmed by serotonin release assay. PF4 concentration did not differ significantly in these patients compared to non-HIT patients (p = 0.37). No patient had an estimated PF4-heparin ratio between 0.7 and 1.4, which is the reported optimal range for PF4-heparin antibody formation. Conclusion: Our data suggest that PF4 concentration is mildly elevated during VA ECMO compared to control plasma. Estimated PF4-heparin ratios were not optimal for HIT antibody formation. These data support epidemiologic studies where HIT incidence is low during VA ECMO