597 research outputs found
Spatial Factors Affecting the Frequency of Pedestrian Traffic Crashes: A Systematic Review
Context: Considering the importance of pedestrian traffic crashes and the role of environmental factors in the frequency of crashes, this paper aimed to review the published evidence and synthesize the results of related studies for the associations between environmental factors and distribution of pedestrian-vehicular traffic crashes.
Evidence Acquisition: We searched all epidemiological studies from 1966 to 2015 in electronic databases. We found 2,828 studies. Only 15 observational studies out of these studies met the inclusion criteria of the study. The quality of the included studies was assessed using the strengthening the reporting of observational studies in epidemiology (STROBE) checklist.
Results: A review of the studies showed significant correlations between a large number of spatial variables including student population and the number of schools, population density, traffic volume, roadway density, socio-economic status, number of intersections, and the pedestrian volume and the dependent variable of the frequency of pedestrian traffic crashes. In the studies, some spatial factors that play an important role in determining the frequency of pedestrian traffic crashes, such as facilities for increasing the pedestrians’ safety were ignored.
Conclusions: It is proposed that the needed research be conducted at national and regional levels in coordination and cooperation with international organizations active in the field of traffic crashes in various parts of the world, especially in Asian, African and Latin American developing countries, where a greater proportion of pedestrian traffic crashes occur
Genetic Research and Women’s Heart Disease: a Primer
PURPOSE OF REVIEW: This review provides a brief synopsis of sexual dimorphism in atherosclerosis with an emphasis on genetic studies aimed to better understand the atherosclerotic process and clinical outcomes in women. Such studies are warranted because development of atherosclerosis, impact of several traditional risk factors, and burden of coronary heart disease (CHD) differ between women and men. RECENT FINDINGS: While most candidate gene studies pool women and men and adjust for sex, some sex-specific studies provide evidence of association between candidate genes and prevalent and incident CHD in women. So far, most genome-wide association studies (GWAS) also failed to consider sex-specific associations. The few GWAS focused on women tended to have small sample sizes and insufficient power to reject the null hypothesis of no association even if associations exist. SUMMARY: Few studies consider that sex can modify the effect of gene variants on CHD. Sufficiently large-scale genetic studies in women of different race/ethnic groups, taking into account possible gene-gene and gene-environment interactions as well as hormone-mediated epigenetic mechanisms, are needed. Using the same disease definition for women and men might not be appropriate. Accurate phenotyping and inclusion of relevant outcomes in women, together with targeting the entire spectrum of atherosclerosis, could help address the contribution of genes to sexual dimorphism in atherosclerosis. Discovered genetic loci should be taken forward for replication and functional studies to elucidate the plausible underlying biological mechanisms. A better understanding of the etiology of atherosclerosis in women would facilitate future prevention efforts and interventions
The lncRNA Growth Arrest Specific 5 regulates cell survival via distinct structural modules with independent functions
There is increasing evidence that the architecture of long non-coding RNAs (lncRNAs) just like that of proteins-is hierarchically organized into independently folding sub-modules with distinct functions. Studies characterizing the cellular activities of such modules, however, are rare. The lncRNA growth arrest specific 5 (GAS5) is a key regulator of cell survival in response to stress and nutrient availability. We use SHAPE-MaP to probe the structure of GAS5 and identify three separate structural modules that act independently in leukemic T cells. The 5' terminal module with low secondary structure content affects basal survival and slows the cell cycle, whereas the highly structured core module mediates the effects of mammalian target of rapamycin (mTOR) inhibition on cell growth. These results highlight the central role of GAS5 in regulating cell survival and reveal how a single lncRNA transcript utilizes a modular structure-function relationship to respond to a variety of cellular stresses under various cellular conditions
The need for national diagnostic reference levels: Entrance surface dose measurement in intraoral radiography
Background: Intraoral radiographies are the most frequent X-ray examinations in humans.
According to International Commission on Radiation Protection (ICRP) recommendations, the
selection of a diagnostic reference level (DRL) should be specific to a country or region. Critical
organs such as thyroid gland are exposed to X-rays in intraoral radiography and these exposures
should be kept as low as reasonably achievable. To assist the development of DRLs for intraoral
radiography, a National Radiation Protection Department-sponsored pilot study was carried out.
Materials and Methods: Thermoluminescent dosimetry (TLD) is widely acknowledged to be
the recommended method for measuring entrance surface doses (ESD). In this study, ESD was
measured using LiF thermoluminescent dosimeters (TLD-100) on the skin (either mandibular or
maxillary arcs) of 40 patients. Three TLD chips were placed on the skin of each patient. The
doses were averaged for each radiography and mean ESD of all patients calculated.
Results: The mean ± SD entrance surface dose at the center of the beam on the patients' skin in
intraoral radiography was 1.173 ± 0.606 mGy (ranged from 0.01 to 0.40 mGy). The mean ESD
for male and female patients were 1.380 ± 0.823, and 1.004 ± 0.258 respectively. No statistically
significant difference was found between these means. Despite its necessity, in national
level, there is no published data on the diagnostic reference levels for intraoral radiography.
However, the results obtained in this study are lower than those reported by investigators in
other countries.
Conclusion: In IR Iran, due to lack of large scale studies, no diagnostic reference levels have
been set for X-ray diagnostic procedures. Due to lack of national diagnostic reference levels, it
is not possible to clarify whether in intraoral radiographies any dose reduction techniques are
needed. We intend to perform similar nationwide studies to set the diagnostic reference level for
intraoal radio graphy
Entrance surface dose measurement on the thyroid gland in orthopantomography: The need for optimization
Background: The anatomic position and proven radiosensitivity of the thyroid make it an
organ of concern in dental X-ray examinations. A National Radiation Protection Department
(NRPD)-sponsored pilot study carried out in the Dental Radiology Department of RUMS., to
assess if the radiation dose in panoramic radiographies could be reduced without significant
impairment of the subjective image quality.
Materials and Methods: Thermoluminescent dosimetry (TLD) is widely acknowledged to be
the recommended method for measuring entrance surface doses (ESD). In this study, ESD was
measured using LiF thermoluminescent dosimeters (TLD-100) on the thyroid of 40 patients
who had referred to the School of Dentistry, Rafsanjan University of Medical Sciences. Patients
were not exposed to any additional radiation and the radiographs were used for diagnostic
purposes. TLDs were calibrated with radiation energies similar to those commonly used in
orthopantomography.
Results: The overall mean ESD on the thyroid in orthopantomography was 0.071 ± 0.012 mGy
(ranged from 0.01 to 0.40 mGy). The mean ESD for radiographies performed with 66 kVp (20
patients) and 68 kVp (20 patients) were 0.072 ± 0.019, and 0.070 ± 0.016 respectively. No statistically
significant difference was found between these means.
Conclusions: The measured surface doses in our study are inconsistent with the only one
already reported about the same experiment. However, due to lack of national diagnostic reference
levels for orthopantomography, it is not clear whether in case of the PM 2002 CC unit used in
this experiment, reducing the radiation dose to a level that still keeps a diagnostically acceptable
image quality is necessary
Temperature - dependent life table of the predatory mite, Amblyseius swirskii (Mesostigmata: Phytoseidae) fed on stored product mite Carpoglyphus lactis (Astigmata: Carpoglyphidae)
The predatory mite, Amblyseius swirskii (Athias-Henriot) is an efficient predator of some insect pests particularly thrips and whiteflies. To evaluate the optimum temperature for A.swirskii, a life table study, based on the age-stage, two-sex life table theory, was conducted using the stored product mite, Carpoglyphus lactis L. as the food diet. Experiments were performed at temperatures of 22, 25, 30 and 32° C, %70 ± 5 relative humidity and 16: 8 (L: D) photoperiod. Developmental time of eggs at 30° C was significantly shorter comparing to the temperatures 22 and 32° C. Developmental time of the mobile pre-adult stages, male and female, were significantly shorter at 32° C, comparing to 25° C. The highest fecundity of the predator was observed at 25° C (72.34 eggs / female). The intrinsic rate of increase (r), finite rate of population increase (λ), net reproductive rate (R0), at temperature of 22° C were 0/226 day-1, 1/25 day-1, 25/53 offspring/individual; at 25° C were 0/304 day-1, 1.35 day-1, 33/82 offspring/ individual; at 30° C were 0/097 day-1, 1/102 day-1, 2/42 offspring/ individual; at a temperature of 32° C were 0/128 day-1, 1/137 day-1, 2/67 offspring/ individual. The population parameters of A. swirskii, except mean generation times (T), at 25° C and 32° C were significantly higher than those at 30° C, and the average generation time (T), at temperature of 22° C, was found to be the highest. The total population projection demonstrated that the highest population growth of predatory mite, A. swirskii occurred at 25° C
Effects of imidacloprid, dichlorvos, pymetrozine and abamectin, on life table parameters of the predatory bug, Orius albidipennis (Hemiptera: Anthocoridae)
Effects of four pesticides (imidacloprid, dichlorvos, pymetrozine and abamectin) were evaluated on life table parameters of Orius albidipennis (Reuter). Pesticides were used at the concentrations recommended by the manufacturers. The bioassays were carried out using drum-cell method, in a growth chamber at 27 ± 1ºC, R.H. of 65 ± 5% and 16 h photo phase. The net reproductive rate (R0) value for the populations treated with imidacloprid, dichlorvos, pymetrozine, abamectin and tap water as control was, 2.91 ± 0.48, 18.85 ± 2.55, 10.16 ± 1.21, 8.00 ± 1.05, 43.40 ± 7.64; the intrinsic rate of natural increase (rm) was 0.040 ± 0.005, 0.097 ± 0.018, 0.086 ± 0.012, 0.078 ± 0.010, 0.148 ± 0.006: the mean generation time (T) was 25.60 ± 1.12, 25.94 ± 1.85, 26.37 ± 0.25, 25.61 ± 0.21, 25.20 ± 1.16; the doubling time (DT) was 18.04 ± 2.76, 7.72 ± 1.60, 8.23 ± 1.11, 9.24 ± 1.37, 4.68 ± 0.18, and the finite rate of increase (λ) was 1.041 ± 0.006, 1.102 ± 0.019, 1.090 ± 0.013, 1.081 ± 0.011, 1.160 ± 0.007, respectively. Imidacloprid and dichlorvos, which revealed the most and the least effects on the life table parameters, were the most and the least harmful among the chemicals tested
Markers of atherosclerosis in relation to presence and progression of knee osteoarthritis: the Rotterdam study
Water safety in drought: An indigenous knowledge-based qualitative study
The indigenous knowledge of our ancestors provides valuable information on how to prevent negative health impacts on water hygiene in the event of drought. The present study aimed to explore the role of indigenous knowledge in maintaining water safety in drought conditions. A qualitative content analysis method using in-depth semi-structured interviews was used to collect and analyze the data. The current research was carried out from April 2017 to June 2018. A purposive sampling method was used to select 15 participants. Trustworthiness was applied with the Lincoln and Guba approach and data were analyzed using Graneheim and Lundman's method. Two categories including drinking water storage and water collection were extracted from the data. Each category includes different strategies to deal with water. Water storage includes water quantity and water quality. Water collection consists of collection methods and rules. Indigenous knowledge is an indispensable component of community disaster resilience. It can be transferred to other communities and employed to empower affected communities. But using the knowledge without scientific considerations cannot guarantee peoples' health throughout the drought periods. © IWA Publishing 2020 Journal of Water and Healt
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