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Background: High-efficiency particulate air (HEPA) filters are currently recommended when using recirculated air to eliminate the risk of pathogen transmission such as SARS-CoV-2 from one patient care area to the next. We tested the efficacy of lower-grade air filters in eliminating airborne virus transmission. Methods: We conducted an experiment in 2 adjacent exam rooms in an unoccupied hospital emergency unit. The HVAC system contained a 15,000-cubic-feet-per-minute rooftop air handler. All outside air and exhaust dampers were closed during the trial (full air recirculation). We conducted experiments in 3 tests arms with varying grades of MERV filters (AAF Flanders, Louisville, KY): (1) control without filters, (2) MERV8+14 filters, and (3) MERV8+16 filters. We repeated 20-minute virus challenge runs 3 times per test arm. Live attenuated influenza vaccine (2 mL LAIV, FluMist Quadrivalent 2020/21, AstraZeneca, Wilmington, DE), was aerosolized into the HVAC system via a commercial nebulizer. Air was sampled using 3 six-stage Andersen air samplers placed in the center of the adjacent room. Environmental particle counts were collected using a particle counter (PEC-PCO-1, PCE Americas). Results: Concentrations of viral RNA were determined by qPCR, and viral concentrations (vg/mL) in each stage of each arm were compared directly. Pairwise comparisons of the virus and particle burdens across each stage of each test arm were made using a general linear model. LAIV was detected in the control arm at a virus burden of 2,277 vg/mL, indicating a >6.5 log reduction of the virus released in the HVAC system (8.8×109 total vg). In the second arm, the MERV8+MERV14 filters demonstrated in a 13-fold decrease in viral burden compared to the control arm (mean virus burden: 169 vg/mL, p Our study demonstrates that viral containing particles can be transported via a hospital HVAC system from one patient room to the next. Considering the decrease in detectable virus within the HVAC system, the combination of MERV8+MERV16 filters reduced the virus burden reaching an adjacent room to levels well below the human infectious dosages for influenza and other highly infective viruses. Conclusions: Our findings indicate that MERV8+MERV16 filters provide protection against virus transmission through HVAC systems and are a cost-conscious alternative to HEPA filters.
OBJECTIVES/GOALS: Osteoarthritis (OA) is a cartilage destroying disease. We are investigating abaloparatide (ABL) activation of parathyroid hormone receptor type 1 (PTH1R), which is expressed by articular chondrocytes in OA. We propose ABL treatment is chondroprotective in murine PTOA via stimulation of matrix production and inhibition of chondrocyte maturation. METHODS/STUDY POPULATION: 16-week-old C57BL/6 male mice received destabilization of the medial meniscus (DMM) surgery to induce knee PTOA. Beginning 2 weeks post-DMM, 40 Î¼g/kg of ABL (or saline) was administered daily via subcutaneous injection and tissues were harvested after 6 weeks of daily injections and 8 weeks after DMM surgery. Harvested joint tissues were used for histological and molecular assessment of OA using three 5 Î¼m thick sagittal sections from each joint, 50 Î¼m apart, cut from the medial compartment of injured knees. Safranin O/Fast Green tissue staining and immunohistochemistry-based detection of type 10 collagen (Col10) and lubricin (Prg4) was performed using standard methods. Histomorphometric quantification of tibial cartilage area and larger hypertrophic-like cells was performed using the Osteomeasure system. RESULTS/ANTICIPATED RESULTS: Safranin O/Fast Green stained sections showed a decreased cartilage loss in DMM joints from ABL-treated versus saline-treated mice. Histomorphometric analysis of total tibial cartilage area revealed preservation of cartilage tissue on the tibial surface. Immunohistochemical analyses showed that upregulation of Col10 in DMM joints was mitigated in the cartilage of ABL-treated mice, and chondrocyte expression of Prg4 was increased in uncalcified cartilage areas in ABL-treated group. The Prg4 finding suggests a matrix anabolic effect that may counter OA cartilage loss. Quantification of chondrocytes in uncalcified and calcified tibial cartilage areas revealed a reduction in the number of larger hypertrophic-like cells in ABL treated mice, suggesting deceleration of hypertrophic differentiation. DISCUSSION/SIGNIFICANCE: Cartilage preservation/regeneration therapies would fill a critical unmet need. We demonstrate that an osteoporosis drug targeting PTH1R decelerates PTOA in mice. ABL treatment was associated with preservation of cartilage, decreased Col10, increased Prg4, and decreased number of large hypertrophic-like chondrocytes in the tibial cartilage.
Written to honor the 80th birthday of William Fulton, the articles collected in this volume (the first of a pair) present substantial contributions to algebraic geometry and related fields, with an emphasis on combinatorial algebraic geometry and intersection theory. Featured topics include commutative algebra, moduli spaces, quantum cohomology, representation theory, Schubert calculus, and toric and tropical geometry. The range of these contributions is a testament to the breadth and depth of Fulton's mathematical influence. The authors are all internationally recognized experts, and include well-established researchers as well as rising stars of a new generation of mathematicians. The text aims to stimulate progress and provide inspiration to graduate students and researchers in the field.
Written to honor the 80th birthday of William Fulton, the articles collected in this volume (the second of a pair) present substantial contributions to algebraic geometry and related fields, with an emphasis on combinatorial algebraic geometry and intersection theory. Featured include commutative algebra, moduli spaces, quantum cohomology, representation theory, Schubert calculus, and toric and tropical geometry. The range of these contributions is a testament to the breadth and depth of Fulton's mathematical influence. The authors are all internationally recognized experts, and include well-established researchers as well as rising stars of a new generation of mathematicians. The text aims to stimulate progress and provide inspiration to graduate students and researchers in the field.
Organismal metabolic rates reflect the interaction of environmental and physiological factors. Thus, calcifying organisms that record growth history can provide insight into both the ancient environments in which they lived and their own physiology and life history. However, interpreting them requires understanding which environmental factors have the greatest influence on growth rate and the extent to which evolutionary history constrains growth rates across lineages. We integrated satellite measurements of sea-surface temperature and chlorophyll-a concentration with a database of growth coefficients, body sizes, and life spans for 692 populations of living marine bivalves in 195 species, set within the context of a new maximum-likelihood phylogeny of bivalves. We find that environmental predictors overall explain only a small proportion of variation in growth coefficient across all species; temperature is a better predictor of growth coefficient than food supply, and growth coefficient is somewhat more variable at higher summer temperatures. Growth coefficients exhibit moderate phylogenetic signal, and taxonomic membership is a stronger predictor of growth coefficient than any environmental predictor, but phylogenetic inertia cannot fully explain the disjunction between our findings and the extensive body of work demonstrating strong environmental control on growth rates within taxa. Accounting for evolutionary history is critical when considering shells as historical archives. The weak relationship between variation in food supply and variation in growth coefficient in our data set is inconsistent with the hypothesis that the increase in mean body size through the Phanerozoic was driven by increasing productivity enabling faster growth rates.
We present a novel distributed-memory parallel implementation of the concurrent atomistic-continuum (CAC) method. Written mostly in Fortran 2008 and wrapped with a Python scripting interface, the CAC simulator in PyCAC runs in parallel using Message Passing Interface with a spatial decomposition algorithm. Built upon the underlying Fortran code, the Python interface provides a robust and versatile way for users to build system configurations, run CAC simulations, and analyze results. In this paper, following a brief introduction to the theoretical background of the CAC method, we discuss the serial algorithms of dynamic, quasistatic, and hybrid CAC, along with some programming techniques used in the code. We then illustrate the parallel algorithm, quantify the parallel scalability, and discuss some software specifications of PyCAC; more information can be found in the PyCAC user’s manual that is hosted on www.pycac.org.