Changes of Grocery Shopping Frequencies and Associations with Food Deserts during the COVID-19 Pandemic in the United States.

The COVID-19 pandemic has dramatically altered people's lives in multiple aspects, including grocery shopping behaviors. Yet, the changing trend of grocery shopping frequencies during the COVID-19 and its associations with food deserts remain unclear. We aimed to (1) examine variations of grocery shopping frequencies at county level in the USA during the COVID-19 pandemic from March 2020 to December 2021; (2) investigate associations between grocery shopping frequencies and food deserts during the COVID-19 pandemic; and (3) explore heterogeneity in grocery shopping frequencies-food desert associations across urban and rural areas. The county-level grocery shopping frequencies were derived from a grocery pattern dataset obtained from SafeGraph. We divided the 22-month period into 5 stages and employed the growth curve modeling to estimate the trajectories of grocery shopping frequencies and the associations between grocery shopping frequencies and food deserts in each stage, separately. Results revealed that grocery shopping frequencies experienced a "W-shaped" pattern from March 2020 to December 2021. Counties with the least percent of food deserts had slower decrease in grocery shopping frequencies at the initial stage and recovered more rapidly at later stages. Counties with the highest percent of food deserts were subject to deprivation amplification as a result of the pandemic. We also found differences existed in the grocery shopping frequencies-food desert associations between metropolitan counties and rural counties. Our findings suggest the impacts of COVID-19 on grocery shopping frequencies varied across different time periods, shedding light on designing different strategies to reduce the risk of contagion while shopping inside of grocery stores. Further, our findings highlight an urgent need to help people living in food deserts (especially in rural counties) to procure healthy foods safely during health emergencies like COVID-19 pandemic which disrupt mobility and social behaviors.

Positive Platinum anomalies at three late Holocene high magnitude volcanic events in Western Hemisphere sediments.

Changes in the global atmospheric budget of platinum reportedly correspond to explosive volcanic eruptions. Using inductively coupled plasma mass spectrometry (ICP-MS) elemental analysis we examined eight widely separated stratified sites to evaluate the geographic extent of three late Holocene high magnitude volcanic events. We found characteristic Pt anomalies across the Western Hemisphere dating to the Laki, Iceland (CE 1783-1784), Kuwae, Vanuatu (CE 1452-1453), and Eldgjá, Iceland (CE 934) explosive volcanic eruptions. Pt anomalies in sediments over a broad geographic area indicate distinctive time-correlative atmospheric deposition rates of platinum-rich volcanic ash. These anomalies provide new chronostratigraphic markers for these late Holocene high magnitude volcanic eruptions, which are especially valuable in the Western Hemisphere in strata with limited chronometric control. Pt anomalies provide an important tracer for the age of these volcanic events and ultimately a new chronostratigraphic marker in archaeological, geological, palynological, and paleontological sediments.

Combined effect of bisphosphonate and recombinant human bone morphogenetic protein 2 on bone healing of rat calvarial defects.

BACKGROUND: This study aimed to investigate new bone formation using recombinant human bone morphogenetic protein 2 (rhBMP-2) and locally applied bisphosphonate in rat calvarial defects. METHODS: Thirty-six rats were studied. Two circular 5 mm diameter bony defect were formed in the calvaria using a trephine bur. The bony defect were grafted with Bio-Oss® only (group 1, n = 9), Bio-Oss® wetted with rhBMP-2 (group 2, n = 9), Bio-Oss® wetted with rhBMP-2 and 1 mM alendronate (group 3, n = 9) and Bio-Oss® wetted with rhBMP-2 and 10 mM alendronate (group 4, n = 9). In each group, three animals were euthanized at 2, 4 and 8 weeks after surgery, respectively. The specimens were then analyzed by histology, histomorphometry and immunohistochemistry analysis. RESULTS: There were significant decrease of bone formation area (p < 0.05) between group 4 and group 2, 3. Group 3 showed increase of new bone formation compared to group 2. In immunohistochemistry, collagen type I and osteoprotegerin (OPG) didn't show any difference. However, receptor activator of nuclear factor κB ligand (RANKL) decreased with time dependent except group 4. CONCLUSION: Low concentration bisphosphonate and rhBMP-2 have synergic effect on bone regeneration and this is result from the decreased activity of RANKL of osteoblast.

Bone Healing in Ovariectomized-rabbit Calvarial Defect with Tricalcium Phosphate Coated with Recombinant Human Bone Morphogenetic Protein-2 Genetically Engineered in Escherichia coli.

PURPOSE: This study compares the bone formation ability of tricalcium phosphate (TCP) with and without recombinant human bone morphogenetic protein-2 (rhBMP-2) and assesses TCP as a carrier of rhBMP-2. METHODS: Bilateral round defects (diameter: 8.0 mm) were formed in the cranium of eight New Zealand white rabbits. The defects were grafted with TCP only (control group) or with rhBMP-2-coated TCP (experimental group). The animals were sacrificed at 1st week, 2nd week, 4th week, and 8th week postoperatively; two rabbits sacrificed each time. The skulls were harvested and subjected to radiographic and histological examination. RESULTS: Radiologic evaluation showed faster bone remodeling in the experimental group than in the control group. Histologic evaluation (H&E, Masson's trichrome stain) showed rapid bone formation, remodeling and calcification in the 1st and 2nd week in the experimental group. Immunohistochemical evaluation showed higher expression rate of osteoprotegerin, receptor activator of nuclear factor κB ligand, and receptor activator of nuclear factor κB in the experimental group at the 1st and 2nd week than in the control group. CONCLUSION: rhBMP-2 coated TCP resulted in rapid bone formation, remodeling, and calcification due to rhBMP-2's osteogenic effect. TCP performed properly as a carrier for rhBMP-2. Thus, the use of an rhBMP-2 coating on TCP had a synergic effect on bone healing and, especially, bone remodeling and maturation.

Characterizing bicycle collisions by neighborhood in a large Midwestern city.

INTRODUCTION: Local environmental factors provide important contributions to bicycle safety. The purpose of this study was to characterize bicycle collisions by neighborhood in Cincinnati, Ohio. BACKGROUND: The majority of prior bicycle safety research has focused on helmet use, especially among youth. Studies that have considered the neighborhood have centered on the built environment and its facilitation of bicycling (e.g., connectivity of roads and road conditions). Other broad conditions may be associated with injury beyond the use of protective equipment and the physical environment. METHOD: This study sought to determine spatial clustering, local patterning, temporal differences (time of day and season of year), and significant neighborhood-level predictors of bicycle collisions. Bicycle collision data were obtained from the Cincinnati, Ohio Police Department. CONCLUSIONS: This study showed that collisions occur at higher rates in the south-central and southwest neighborhoods of Cincinnati, Ohio. There were seasonal and time-of-day differences with respect to collision rates with summer and afternoon being the most common collision times. Neighborhood ethnicity, population density and presence of public transportation were all significant predictors of bicycle collisions. These findings will be disseminated to local city authorities and bicycle advocacy groups.