24 research outputs found
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Mixed Student Ideas about Mechanisms of Human Weight Loss
Recent calls for college biology education reform have identified “pathways and transformations of matter and energy” as a big idea in biology crucial for students to learn. Previous work has been conducted on how college students think about such matter-transforming processes; however, little research has investigated how students connect these ideas. Here, we probe student thinking about matter transformations in the familiar context of human weight loss. Our analysis of 1192 student constructed responses revealed three scientific (which we label “Normative”) and five less scientific (which we label “Developing”) ideas that students use to explain weight loss. Additionally, students combine these ideas in their responses, with an average number of 2.19 ± 1.07 ideas per response, and 74.4% of responses containing two or more ideas. These results highlight the extent to which students hold multiple (both correct and incorrect) ideas about complex biological processes. We described student responses as conforming to either Scientific, Mixed, or Developing descriptive models, which had an average of 1.9 ± 0.6, 3.1 ± 0.9, and 1.7 ± 0.8 ideas per response, respectively. Such heterogeneous student thinking is characteristic of difficulties in both conceptual change and early expertise development and will require careful instructional intervention for lasting learning gains
Synchrotron light source X-ray detection with Low-Gain Avalanche Diodes
The response of Low Gain Avalanche Diodes (LGADs), which are a type of thin
silicon detector with internal gain, to X-rays of energies between 6-70 keV was
characterized at the SLAC light source (SSRL). The utilized beamline at SSRL
was 11-2, with a nominal beam size of 3 cm x 0.5 cm, a repetition rate of 500
MHz, and very monochromatic. LGADs of different thicknesses and gain layer
configurations were read out using fast amplification boards and digitized with
a fast oscilloscope. Standard PiN devices were characterized as well. The
devices' energy resolution and time resolution as a function of X-ray energy
were measured. The charge collection and multiplication mechanism were
simulated using TCAD Sentaurus, and the results were compared with the
collected data.Comment: 18 pages, 18 figure
Army Tactical Wheeled Vehicles: Current Fleet Profiles and Potential Strategy Implications (Publication Announcement)
A publication announcement created for an event at the Dudley Knox Library, Naval Postgraduate Schoo
Army Tactical Wheeled Vehicles: Current Fleet Profiles and Potential Strategy Implications
This report documents the results of a multipart research project on evolving a fleet strategy for
Army tactical wheeled vehicles. The first phase of the study focused on the light tactical vehicle
fleet. The second phase focused on the medium and heavy tactical vehicle fleets, specifically
building a status profile that shows the Army where it currently stands in terms of the types,
quantities, and years of useful life remaining in its medium and heavy tactical wheeled vehicle
fleets.United States Army.RAND Arroyo Center’s Force Development and Technology Program
Cross-Reactive Plasmonic Aptasensors for Controlled Substance Identification
In this work, we developed an assay to determine if an arbitrary white powder is a controlled substance, given the plasmonic response of aptamer-gold nanoparticle conjugates (Apt-AuNPs). Toward this end, we designed Apt-AuNPs with specific a response to common controlled substances without cross reactivity to chemicals typically used as fillers in street formulations. Plasmonic sensor variation was shown to produce unique data fingerprints for each chemical analyzed, supporting the application of multivariate statistical techniques to annotate unknown samples by chemical similarity. Importantly, the assay takes less than fifteen minutes to run, and requires only a few micrograms of the material, making the proposed assay easily deployable in field operations
Durable reduction of Clostridioides difficile infection recurrence and microbiome restoration after treatment with RBX2660: results from an open-label phase 2 clinical trial
Background
Effective treatment options for recurrent Clostridioides difficile infection (rCDI) are limited, with high recurrence rates associated with the current standard of care. Herein we report results from an open-label Phase 2 trial to evaluate the safety, efficacy, and durability of RBX2660—a standardized microbiota-based investigational live biotherapeutic—and a closely-matched historical control cohort.
Methods
This prospective, multicenter, open-label Phase 2 study enrolled patients who had experienced either ≥ 2 recurrences of CDI, treated by standard-of-care antibiotic therapy, after a primary CDI episode, or ≥ 2 episodes of severe CDI requiring hospitalization. Participants received up to 2 doses of RBX2660 rectally administered with doses 7 days apart. Treatment success was defined as the absence of CDI diarrhea without the need for retreatment for 8 weeks after completing study treatment. A historical control group with matched inclusion and exclusion criteria was identified from a retrospective chart review of participants treated with standard-of-care antibiotics for recurrent CDI who matched key criteria for the study. The primary objective was to compare treatment success of RBX2660 to the historical control group. A key secondary outcome was the safety profile of RBX2660, including adverse events and CDI occurrence through 24 months after treatment. In addition, fecal samples from RBX2660-treated participants were sequenced to evaluate microbiome composition and functional changes from before to after treatment.
Results
In this Phase 2 open-label clinical trial, RBX2660 demonstrated a 78.9% (112/142) treatment success rate compared to a 30.7% (23/75) for the historical control group (p < 0.0001; Chi-square test). Post-hoc analysis indicated that 91% (88/97) of evaluable RBX2660 responders remained CDI occurrence-free to 24 months after treatment demonstrating durability. RBX2660 was well-tolerated with mostly mild to moderate adverse events. The composition and diversity of RBX2660 responders’ fecal microbiome significantly changed from before to after treatment to become more similar to RBX2660, and these changes were durable to 24 months after treatment.
Conclusions
In this Phase 2 trial, RBX2660 was safe and effective for reducing rCDI recurrence as compared to a historical control group. Microbiome changes are consistent with restorative changes implicated in resisting C. difficile recurrence.
Clinical Trials Registration NCT02589847 (10/28/2015)Medicine, Faculty ofNon UBCPathology and Laboratory Medicine, Department ofReviewedFacultyResearche