Effect of Thermal and Mechanical Aging on Flexural Strength of Zirkonzahn and Mamut Zirconia Ceramics

Objective: Despite the high strength of zirconia restorations, aging in the oral environment and masticatory loading may result in transformation of tetragonal to monoclinic phase and decrease their strength. Statements in this regard are controversial. This study sought to compare the flexural strength (FS) of Zirkonzahn (ZirkonZahn, Cercon, Ceramill) and Mamut (Dubai Medical Equipment LLC, Dubai, UAE) zirconia ceramics and assess the effect of thermal and mechanical aging on their FS.Methods: In this in vitro experimental study, 40 bar-shaped specimens measuring 20×5×2 mm were cut from Zirkonzahn and Mamut zirconia blocks and polished. Specimens in the aging groups were subjected to thermocycling (12,000 cycles, 5-55°C, dwell time of 20 seconds). Next, they were subjected to mechanical stress in a chewing simulator (40,000 cycles, 200N force). The three-point flexural strength (TPFS) was determined in megapascal (MPa) using a Universal Testing Machine at a crosshead speed of 0.5 mm/min. Data was analyzed using two-way ANOVA.Results: The mean and standard deviation (SD) of TPFS of Zirkonzahn and Mamut specimens in the no aging group was 809.57 (205.95) and 708.53 (158.72) MPa, respectively. These values were810.53 (158.96) and 839.06 (217.49) MPa for the Zirkonzahn and Mamut specimens subjected to aging, respectively. Type of zirconia (Zirkonzahn or Mamut) and exposure to aging process (p=0.27) had no significant effect on TPFS of specimens.Conclusion: Within the limitations of this study, the results showed that the process of aging did not decrease the TPFS of Zirkonzahn and Mamut specimens. Thus, these ceramics may be successfully used in the clinical setting

Variations in national availability of waivered buprenorphine prescribers by racial and ethnic composition of zip codes

Background Opioid overdose remains a public health crisis in diverse communities. Between 2019 and 2020, there was an almost 40% increase in drug fatalities primarily due to opioid analogues of both stimulants and opioids. Medications for opioid use disorder (MOUD; e.g., buprenorphine) are effective, evidence-based treatments that can be delivered in office-based primary care settings. We investigated disparities in the proportion of national prescribers who have obtained a waiver issued to prescribe MOUD by demographic characteristics. Methods Data for the secondary data analyses were obtained from the Drug Enforcement Administration that maintains data on waivered MOUD prescribers across the US. Proportion of waivered prescribers were examined by ZIP code, race and ethnicity composition, socioeconomic status, insurance, and urban–rural designation using generalized linear mixed effects models. Results Compared with predominantly Non-Hispanic White ZIP codes, other racially and ethnically diverse areas had a higher proportion of waivered buprenorphine prescribers. Differences in prescriber availability between predominant racial group was dependent on rurality based on the interaction found in our fitted model. In metropolitan areas, we found that predominantly Non-Hispanic White ZIP codes had a lower rate of waivered prescribers compared to predominantly Black/African American ZIP codes. Conclusions Our findings suggest that among AI/AN and Black/African American neighborhoods, availability of waivered prescribers may not be a primary barrier. However, availability of waivered prescribers and prescribing might potentially be an obstacle for Hispanic/Latinx and rural communities. Additional research to determine factors related to improving MOUD availability among diverse communities therefore remains vital to advancing health equity

Testing a Geospatial Predictive Policing Strategy Application of ArcGIS 3D Analyst Tools for Forecasting Commission of Residential Burglaries

Classical placed-based crime prevention theories suggest existence of a relationship between certain characteristics of spatial design and configuration and crime occurrence. This study explored the relationship between natural surveillance - one of the least studied and understood principles of crime prevention through environmental design (CPTED) - and burglary commissions in three-dimensions.Natural surveillance has been claimed to differ when seen by neighbors, pedestrian passersby or individuals in vehicles, and to be influenced by viewing distance. Thus, the notion of natural surveillance was quantified to three categories of occupant, road and pedestrian surveillability. In addition, length of sightlines were restricted by the distance at which human eye is considered effective to eyewitness and interpret events.Employing a mixed methods research design, qualitative data (sketches made from oblique aerial imagery, field observations of architectural and landscape features, burglary crime reports and field observations of crime sites) were embedded and provided a supportive role for the quantitative data (georeferenced spatial and crime data) and quantitative analysis (univariate and multivariate statistical analysis). Firstly, ArcGIS geospatial tools were utilized for processing spatial and crime data in three-dimensions. Then, ESRI ModelBuilder was employed for automating the procedure of enumerating natural surveillance intensity.Spearman's rank correlation, Mann-Whitney U and binary logistic regression were employed to investigate the univariate and multivariate association between natural surveillance and burglary commissions or burglary occurrence. The results at the building opening level revealed that the log of the odds of burglary commission was negatively related to occupant surveillability and positively related to road surveillability. Findings at the building level showed that the log of the odds of residential burglary occurrence was positively related to road surveillability.This research shed light on the importance of the notion of "eyes upon the street" (Jacobs, 1961) even in a low socioeconomic-high criminogenic area. It has implications for developing proactive design and planning policies to help design crime out at the early stages of planning and development. It also demonstrates how law enforcement can further leverage societal investments in geospatial data to benefit public safety more effectively

Effect of Catalyst, Temperature, and Hydrogen Pressure on Slurry Hydrocracking Reactions of Naphthalene

Hydrocracking reactions of naphthalene were investigated in a slurry-type reactor with different catalyst compositions consisting of iron-based compounds, metal oxides, and elementary sulfur in order to evaluate the most efficient catalyst composition. The reactions were repeated with the optimal catalyst composition at different H-2 initial pressures, temperatures, and holding times to determine the influence of these parameters. At the end of each reaction, liquid samples were analyzed by gas chromatography and mass spectrometry. The most effective catalyst composition for hyrocracking reaction of naphthalene was found to be a mixture of FeSO4 center dot H2O, Fe2O3, Al2O3, and sulfur. It can be concluded that hydrogenation, isomerization, cracking, and dealkylation take place during the hydrocracking reaction of naphthalene

An economic evaluation of a forest park using the individual travel cost method (a case study of Ghaleh Rudkhan forest park in northern Iran)

The true economic value of ecosystem services may not be reflected in market transactions, because there is no real transaction for ecosystem services in the market. Therefore, it is important to evaluate the cost of time and travel to define the value people place on something in the absence of a market price. This study estimates the recreational value of Ghaleh Rudkhan forest park in the north of Iran using the individual travel cost method. This method is considered to be a substitute approach for the market. The data required were collected using questionnaires. Therefore, 271 questionnaires were randomly distributed between the visitors of the recreational site in 2016. In this study, a linear function is used to estimate the effects of explanatory variables including economic and social variables on the number of visits to estimate the recreational value of the forest park. Results showed that a consumer surplus of each person for their visit was 21500 Rials and the annual recreational value of the park was 78390595 Rials per ha. Furthermore, the variables such as travel expenses, income, distance, family size and visitor's age are effective factors in the recreational use of the park. The results of this study can improve the quality of environmental services of the Ghaleh Rudkhan forest park and could expand the variety of services that they could supply based on the demand of the people

Environmental Correlates of Reaching a Centenarian Age: Analysis of 144,665 Deaths in Washington State for 2011−2015

Objective: This study examined the association of several social and environmental factors on the likelihood of reaching centenarian age for older adults in Washington State. Methods: A survival analysis of reaching centenarian age for older adults aged 75 years and above was performed using Washington State mortality data from 2011−2015. Models were adjusted for sex, race, education, marital status, and neighborhood level social and environmental variables at the block group level. Geographic clusters of increased chance of becoming a centenarian were also mapped. Results: In the adjusted model, increased neighborhood walkability, lower education level, higher socioeconomic status, and a higher percent of working age population were positively associated with reaching centenarian age. Being widowed, divorced/separated, or never married were also positively correlated compared to being married. Additionally, being white or female were positively correlated with reaching centenarian status. Discussion: Several social and environmental factors are correlated with becoming a centenarian in Washington State. In this study, we explore findings that are consistent with previous research, as well as some that have not been previously explained. More research is needed to expand upon these findings in this rapidly growing field

Cytotoxic and apoptogenic effects of Bryonia aspera root extract against Hela and HN-5 cancer cell lines

Objective: Bryonia aspera (Stev. ex Ledeb) is a plant that grows in northeast of Iran. In the present study, cytotoxic and apoptogenic properties of B. aspera root extract was determined against HN-5(head and neck squamous cell carcinoma) and Hela (cervix adenocarcinoma) cell lines. Materials and Methods: HN-5 and Hela cell lines were cultured in DMEM medium and incubated with different concentrations of B. aspera root extract. Cell viability was quantitated by MTT assay and the optical absorbance was measured at 570 nm (620 nm as the reference) by an ELISA reader, in each experiment. Apoptotic cells were assessed using PI staining of DNA fragmentation by flow cytometry (sub-G1 peak). The B. aspera inhibited 50% growth (IC50) of Hela and HN-5 cell lines at 100±28 μg/ml and 12.5±4 μg/ml, respectively after 48 hr of incubation. Results: Cell viability assay showed that inhibitory effects of B. aspera were time and dose-dependent in both cell lines, which were consistent with morphological changes, observed under light microscope. Apoptosis was investigated by flow cytometry in which percentage of apoptotic cells increased in a dose and time-dependent manner. Conclusion: Based on our data, B. aspera has cytotoxic effects in which apoptosis played an important role. Further evaluations are needed to assess the possible anti-tumor properties of this plant

Trends in Alzheimer Disease Mortality Among American Indian and Alaska Native People Between 2011 and 2019.

PurposeThe number of American Indian and Alaska Native (AI/AN) people living with dementia is expected to increase 5-fold by 2060. Social determinants of health may explain disparities in the incidence of Alzheimer disease (AD) but remain largely overlooked.MethodsWe examined the time trend of AD mortality rates and associations of the percentage of AI/ANs, density of primary care physicians and neurologists, area deprivation index, rurality, and Indian Health Service region with AD mortality in 646 purchased/referred care delivery area counties.ResultsAD mortality rates significantly increased over time. Counties with higher concentrations of AI/AN people had lower AD mortality. More deprived counties had 34% higher AD mortality compared with less deprived counties. AD mortality was 20% lower in nonmetro counties than in metro counties.ConclusionsFindings have implications for prioritizing areas where more resources for AD care, education, or outreach are needed