exposure rate
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Author(s):  
C. Mgbeokwere ◽  
C. P. Ononugbo ◽  
A. Bubu

Background ionizing radiation around Lead/Zinc mining sites at Ishiagu, Ebonyi State was carried out using appropriate equipment. The background ionizing radiation of the environment was determined by measuring the radiation exposure rates using Radalert-200 and Geographical Positioning System (GPS). Radiological health parameters and effective dose to different organs of the body was estimated. The average exposure rate of 0.00017mSv/h (0.017mR/h) measured was relatively higher than the world acceptable value of 0.00013mSv/h (0.013mR/h ). All the radiological risk parameters estimated are relatively high. The result of this work shows that the mining µactivities have enhanced the radiation level of Ishiagu and health status of the populace.


2021 ◽  
Author(s):  
Jason Cosens Walsman ◽  
Alexander T Strauss ◽  
Jessica Hite ◽  
Marta S Shocket ◽  
Spencer R Hall

Most evolutionary theory predicts that, during epidemics, hosts will evolve higher resistance to parasites that kill them. Here, we provide an alternative to that typical expectation, with an explanation centered on resource feedbacks. When resistance is costly, hosts evolve decreasing resistance without parasites, as expected. But with parasites, hosts can evolve lower resistance than they would in the absence of parasites. This outcome arises in an eco-evolutionary model when four conditions are met: first, resistance has a fecundity cost (here, via decreased foraging/exposure rate); second, resources increase during epidemics via trophic cascades; third, increased resources magnify the benefit of maintaining a fast foraging rate, thereby magnifying the cost of evolving a slower foraging/exposure rate (i.e., resistance); fourth, that amplification of the cost outweighs the benefit of resistance. When these conditions are met, hosts evolve lower resistance than without parasites. This phenomenon was previously observed in a mesocosm experiment with fungal parasites, zooplankton hosts, and algal resources. Re-analyzing this experiment produced evidence for our model's mechanism. Thus, both model and experiment indicate that, via resource feedbacks, parasites can counterintuitively select against resistance.


2021 ◽  
Author(s):  
Michael Williams Martynowycz ◽  
Max T.B. Clabbers ◽  
Johan Hattne ◽  
Tamir Gonen

Structures of two globular proteins were determined ab initio using microcrystal electron diffraction (MicroED) data that was collected on a direct electron detector in counting mode. Microcrystals were identified using a scanning electron microscope (SEM) and thinned with a focused ion-beam (FIB) to produce crystalline lamellae of ideal thickness. Continuous rotation data were collected using an ultra-low exposure rate on a Falcon 4 direct electron detector in electron-counting mode. For the first sample, triclinic lysozyme extending to 0.87 A resolution, an ideal helical fragment of only three alanine residues provided initial phases. These phases were improved using density modification, allowing the entire atomic structure to be built automatically. A similar approach was successful on a second macromolecular sample, proteinase K, which is much larger and diffracted to a modest 1.5 A resolution. These results demonstrate that macromolecules can be determined to sub-Angstrom resolution by MicroED and that ab initio phasing can be successfully applied to counting data collected on a direct electron detector.


Growing the volume and influence of the association's assaults, compelling corporate constructions to fix the association's security arrangements to keep away from tremendous money related mishaps. Blackout identification frameworks are presumably the most basic security gadgets to guarantee the security of any association. When pondering tremendous volumes of data about the association and complex nature of blackouts, improving on the introduction of the organization interruption location framework has become an open inquiry that is acquiring and more thought by researchers in nowadays. The objective of this report is to recognize an AI estimation that gives high exactness and a nonstop casing application. This article evaluates the openness of 15 distinctive AI computations utilizing the NSL-KDD dataset dependent on the bogus exposure rate, ordinary exactness, root mean square mistake, and model form time. Initial, 5 of the 15 AI computations are chosen dependent on the most limit accuracy and minimal mistake in WEKA. Entertainment of these AI estimations is done through a ten-time cross-endorsement. From that point, the best AI estimation is picked dependent on the most extreme exactness and least edge season of the model, so it tends to be performed rapidly and logically in interruption recognition frameworks


Author(s):  
Kiddee Poomprakobsri ◽  
Joseph Y Kan ◽  
Kitichai Rungcharassaeng ◽  
Jaime Lozada

The purpose of this study is to compare exposure rate of three different barrier types after a guided-bone regenerationprocedure, as well as to compare the percentage grafted bone dimensional loss with and without exposed barriers. Patient records from September 2007 to May 2015 were reviewed to identify subjects that had received bone graft and then implant placement procedure after the graft is completely healed. The subjects were divided into 3 groups: 1) resorbable barrier 2) non-resorbable barrier, and 3) titanium-mesh barrier. Incidences of barrier exposure were recorded.  Cone-beam computed tomography images before treatment (T0), right after grafting (T1), and after healing (T2) were used to determine percentage grafted bone dimensional loss (%) and quantitative grafted bone remained (mm 2 ). Three cross-sectioned areas, at 1mm apart, of preplanned implant positions at the grafted site were measured on cone-beam computed tomography to calculate for grafted bone remained and grafted bone dimensional change. The exposure rate of all guided bone regeneration was 36.9%. Exposure rate of resorbable barrier (23.3%) is significantly lower than Titanium mesh (68.9%) and Non-resorbable (72.7%) (Chi-Square, P < .001).  The result from this study revealed that barrier types have significant effect on exposure rate. There was also a significant different in grafted bone dimensional loss in sites with barrier exposure (58.3%) and sites with no barrier exposure (44.1%) during the healing period (Mann-Whitney U, P = .008).


Author(s):  
Boram Sim ◽  
Myung-Bae Park

This study aimed to estimate the secondhand smoke (SHS) exposure using urinary cotinine (UCo) to prove that the SHS exposure could not be properly assessed by self-reporting (SR). In total, 28,574 nonsmokers aged >19 years were selected from the Korean National Health and Nutrition Examination Survey data (2009–2018). First, changes in the annual concentration of UCo were analyzed, and the annual SHS exposure rates were measured based on SR and UCo from 2009 to 2018. Then, the average UCo concentration and UCo-measured SHS exposure rate were confirmed according to the subjects’ characteristics. Finally, factors associated with the UCo-measured SHS exposure rate were identified based on multiple regression analysis. The findings showed that the annual UCo concentrations and self-reported SHS exposure rates dropped significantly over the past decade. In contrast, the UCo-measured SHS exposure rate indicated that >80% of nonsmokers are still exposed to SHS. Moreover, we found vulnerable groups using UCo-measured SHS exposure rate. In particular, the self-reported SHS exposure at home and in workplaces and house type was highly associated with SHS exposure. Thus, these findings indicate that the actual SHS exposure could not be properly assessed by SR and should be verified using a biomarker, such as UCo. Considering that even a short-term exposure can be harmful to health, the goal of the policy should be to keep cotinine concentration as low as possible.


Author(s):  
Issaka Sagara ◽  
John Woodford ◽  
Mamady Kone ◽  
Mahamadoun Hamady Assadou ◽  
Abdoulaye Katile ◽  
...  

Abstract Background The extent of SARS-CoV-2 exposure and transmission in Mali and the surrounding region is not well understood. We aimed to estimate the cumulative incidence of SARS-CoV-2 in three communities, and understand factors associated with infection. Methods Between July 2020 and January 2021, we collected blood samples and demographic, social, medical, and self-reported symptoms information from residents aged 6 months and older over two study visits. SARS-CoV-2 antibodies were measured using a highly specific two-antigen ELISA optimized for use in Mali. We calculated cumulative adjusted seroprevalence for each community and evaluated factors associated with serostatus at each visit by univariate and multivariate analysis. Results Overall, 94.8% (2533/2672) of participants completed both study visits. A total of 31.3% (837/2672) were aged <10 years, 27.6% (737/2672) were aged 10-17 years, and 41.1% (1098/2572) were aged ≥18 years. The cumulative SARS-CoV-2 exposure rate was 58.5% (95% CI: 47.5 to 69.4). This varied between sites and was 73.4% in the urban community of Sotuba, 53.2% in the rural town of Bancoumana, and 37.1% in the rural village of Donéguébougou. Study site and increased age were associated with serostatus at both study visits. There was minimal difference in reported symptoms based on serostatus. Conclusion The true extent of SARS-CoV-2 exposure in Mali is greater than previously reported and may now approach hypothetical ‘herd immunity’ in urban areas. The epidemiology of the pandemic in the region may be primarily subclinical and within background illness rates.


Author(s):  
Libo Zhou ◽  
yucheng su ◽  
Jing Wang ◽  
Jiaqi Wang ◽  
Xinyu Wang ◽  
...  

Titanium mesh exposure is the main complication of bone regeneration. In this study, a meta-analysis and performed to clarify the effect of customized titanium mesh versus conventional titanium mesh complications and the time of mesh exposure on edentulous alveolar ridge GBR. Databases, including PubMed, EMBASE, Web of Science and Cochrane Central Register Controlled Trials, were searched by two independent reviewers to retrieve articles published from January 2010 to March 2020, regarding the incidence of complications after GBR surgery, with language limited to English articles. A total of 705 articles were found, and 9 articles were quantitatively analyzed. A funnel plot was made for 10 comprehensive datasets. The combined value of the total exposure rate of titanium mesh was 0.44 (44%, 95% CI=0.30~0.58). The results of subgroup analysis showed that the combined value of the customized titanium mesh exposure rate was 0.31 (31%, 95% CI=0.15~0.51), and the combined value of the conventional titanium mesh exposure rate was 0.51 (51%, 95% CI=0.33~0.69). Based on the findings of the present study, the exposure rate of customized titanium mesh is lower than that of conventional titanium mesh. The design of 3D printing customized titanium mesh avoids nerves and blood vessels, which is of great significance to improve the accurate reconstruction of GBR and provides enough space for implantation and reducing the exposure rate. Soft tissue management (i.e., technical sensitivity) is also an important factor to avoid soft tissue fractures.


Author(s):  
I. U James ◽  
E Onuh ◽  
I. F Moses ◽  
U. E Ukeme ◽  
J. N Vandi

Background: Scrap metal can contain sources of radiation with the associated environmental and health risks. Radioactive substances can become associated with scrap metal in various ways and if not discovered they can be incorporated into steel and non-ferrous metals through the melting process. This can cause health hazards to workers and to the public as well as environmental concerns Objectives: this study aimed at assessing the outdoor radiation exposure levels and human health risk in a major scrap metal market in Abuja, FCT. Method: An in-situ measurement approach was adopted using a factory calibrated Radiagem-2000 Universal Survey Meter and a handheld Global Positioning System (Garmin GPS 76S) equipment. The monitor was suspended in air at one meter above the ground level. Readings were obtained between the hours of 1200 and 1600 hours since the exposure rate meter has a maximum response to environmental radiation within these hours. Results: The results showed that the average values for the outdoor exposure dose rate for the three location ranges from 0.173±0.042 μSv/h to 0.177±0.046 μSv/h with a mean of 0.176±0.045 μSv/h. These values, though, slightly higher than the standard background radiation of 0.133 μSv/h,are below the ICRP maximum permissible limit of 0.57 μSv/h. The results also show that the AEDE values are lower than the ICRP recommended limits of 1.0 mSv/y for the public and 20 mSv/y for occupationally exposed workers. The ELCR ranges from 0.5926 x 10-3 to 0.6049 x 10-3 with a mean of 0.6008 x 10-3 which is 2.1 times higher than the world’s average. The dosage to organs received shows that the testes have the highest dose while the liver has the lowest dose. The result of the dose to the organs showed that all the values are below the international tolerable limits. Conclusion: Generally, The radiological assessment shows that the study area does not constitute any immediate radiological health effect on the workers and the general public due to radiation exposure rate.


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