Quantification of Titanium Release From Titanium Dioxide Impregnated Composites in Orthodontic Bonding—An In Vitro Study

Objective To evaluate the quantity of titanium dioxide nanoparticles released into the artificial salivary medium from orthodontic composite impregnated with 1% weight/weight (w/w) and 5% w/w titanium dioxide nanoparticles (TiO2 NPs) used for bonding metal brackets, thereby eventually comprehending the permissible levels. Materials and Method Eighty freshly extracted teeth for orthodontic treatment were divided into 2 groups of 40 teeth each and were bonded with brackets containing 1% w/w and 5% w/w composite containing titanium dioxide nanoparticles and placed in an artificial salivary medium. Quantification of 1% w/w and 5% w/w composite containing titanium nanoparticles was done using inductively coupled plasma mass spectroscopy for 4 timely periods 24 h, 2 months, 4 months, and 6 months. Results In the teeth that received 1% TiO2, the amount of titanium released was greatest in 2 months with no significant release at later intervals. In the second group that received 5%, there was a significant release of titanium at all intervals, with highest release at second month. On comparing the 2 concentrations at 4 different time intervals, the quantities were significantly greater in the 5% group at all time frames, thus implying a significant increase in titanium released with an increase in concentration from 1% to 5%. Conclusion Titanium release was higher in 5% w/w composite containing nanoparticles than 1% w/w composite containing nanoparticles, and 1% and 5% concentrations can be used safely and are within the permissible limits.

Toxic Metal Concentrations in Drinking Water and Possible Effect on Sex Hormones among Men in Sabongida-Ora, Edo State, Nigeria

Drinking water can be a potential source of toxic metals, which are a known leading cause of infertility in men. This study determines the concentrations of lead (Pb), cadmium (Cd), zinc (Zn), copper (Cu) in drinking water (borehole, hand-dug well and treated water) and sex hormone levels (serum follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PROL), estradiol (E2), progesterone (PROG), and testosterone (T) in males who drink water mainly from these sources. The concentrations of Cd, and Pb in hand-dug wells were higher than the permissible limit recommended by the World Health Organization (WHO) while Zn and Cu were within the permissible levels in drinking water. Blood Cd and Pb levels were significantly higher (p < 0.001) among subjects who consumed hand-dug and borehole water than treated water, while serum Zn was significantly lower (p < 0.001) in hand-dug well and borehole water consumers than in control subjects. Also, serum FSH (p < 0.001), LH (p < 0.001), E2 (p < 0.002), PROG (p < 0.04) and T (p < 0.001) were significantly lower among hand-dug well and borehole water consumers than controls, while PROL (p < 0.001) was significantly higher in hand-dug well and borehole water consumers than controls. Blood Cd and Pb levels were significantly higher (p < 0.001) in hand-dug well water consumers than borehole water consumers. The consumption of water from hand-dug wells may have adverse reproductive sequelae among consumers.

Modern ecological and hygienic problems of the agricultural economy associated with development of pond fish farming

The materials on the study of the content of heavy metals and organochlorine pesticides in fish are presented. It has been established that the level of heavy metals and pesticides in fish is influenced by the territorial location of the pond production. Therefore, the content of lead, cadmium and mercury in the liver and gonads of carp was higher than the permissible values for fish growing in ponds located in the city limits near highways. The pesticides DDT and HCH were detected in the organs of fish in the territories of pond fish farming of farms. Residual concentrations of pesticides contained in fish did not exceed the maximum permissible levels. In order to safely consume fish grown near highways by the population, we recommend the removal of internal organs (liver and gonads) from fish products.

Finite Element Analysis of F1 Halo Safety Structure

The Federation Internationale de L’Autobile (FIA) has been working on improving safety of drivers in open wheel racing series. Numerous incidents caused serious impacts on drivers’ lives. The car-to-car collision, car to environment collision and injuries due to flying debris are common threats to these drivers. In 2016 the introduction of Halo surrounding the cockpit was appreciated by the FIA. The following study includes the analysis of this Halo system using Finite Element Analysis (FEA). The dynamic, static and modal analysis is carried out with the help of Simscale software and the results obtained showed the values under permissible levels. Keywords: Finite Element Analysis, Static Analysis, Modal Analysis, Dynamic Analysis, F1 Halo, FIA.

A Study of PM 10, PM 2.5 Concentrations in the Atmospheric Air in Kraków, Poland

The air in Kraków is one of the most polluted in Europe. Polish standards for notification and alert levels for PM10 particulate matterare one of the the highest in Europe and exceed the recommendations of the World Health Organization (WHO) for safe daily concentrations by several times. The article presents the results of airborne dust measurements in three districts of Kraków. The study hasshown that the concentration of PM2.5 and PM10 particulate matter exceeded the annual average permissible levels. Empirical measurements of PM2.5 show significantly higher air pollution values than the data notified by stationary monitoring stations installed intwo locations. The high value of Pearson linear correlation coefficient confirms that weather conditions have a significant impact on airquality in Kraków. Wind speed in the autumn and winter seasons has by far the greatest influence on air quality in al. Krasińskiego,in the Ruczaj and Kurdwanów districts. A strong negative correlation was displayed. Manual measurements should be used to verifydata obtained from air monitoring stations. It is to be expected that, in Kraków, air purity will improve due to the implementation ofan anti-smog resolution and subsidies for the replacement of obsolete heating systems with more environmentally friendly solutions.

Para-Phenylenediamine (PPD) in commercially available Henna preparations in Bangladesh

In Bangladesh Henna is one of the most popular cosmetic products. The leaves of Henna are dried to make powder on which oil or water is mixed to get a paste to stain the body or hair. Although the occurance of contact allergic dermatitis in natural Henna is not so common, but this risk is increased by adding para-Phenylenediamine (PPD), which is used to make the Henna color dark to deep black. According to Scientific Committee on Consumer Products (SCCP), para-Phenylenediamine (PPD) is treated as an allergen and is considered as a very strong potential skin sensitizer. The presence of PPD in the commercially used tube Henna increases the risk of allergic contact dermatitis and several cases have already been reported worldwide. For this study, about 10 Henna samples were randomly collected from 10 selected areas of Dhaka city. The presence of PPD in Henna samples was determined by using High Performance Liquid Chromatography (HPLC). The result showed the presence of PPD in all of the Henna samples at substantial concentrations, ranging between 79.12-204.77 mg/kg where the average range is 142.36 mg/kg, which is much higher than the permissible levels (<2% or 0.1 mg/m3). The finding suggests that there should be a regulation and monitoring condition for the production and distribution of these adulterated Henna products in Bangladesh. Bioresearch Commu. 8(1): 1088-1092, 2022 (January)

Comparative Analysis of Approaches to Regulation and Monitoring of Workers for Internal Radiation Exposure

Purpose: Harmonization and improvement of the system for regulating the internal radiation exposure of workers and the basic requirements for ensuring radiation safety with international requirements and recommendations. Material and methods: Issues related to the development of approaches to regulation and monitoring of workers for internal radiation exposure in the process of evolution of the ICRP recommendations and the national radiation safety standards, are considered. The subject of analysis is the standardized values: dose limits for workers and permissible levels as well as directly related methods of monitoring of workers for internal radiation exposure, whose purpose is to determine the degree of compliance with the principles of radiation safety and regulatory requirements, including non-exceeding the basic dose limits and permissible levels. The permissible levels of inhalation intake of insoluble compounds (dioxide) of plutonium-239 are considered as a numerical example. Results: Based on the analysis of approaches to the regulation and monitoring of workers for internal radiation exposure for the period from 1959 to 2019, it is shown that a qualitative change in the approach occurred in the 1990s. It was due to a decrease in the number of standardized values by introducing a single dose limit for all types of exposure: the effective dose E, which takes into account the different sensitivity of organs and tissues for stochastic radiation effects (WT), using the previously accepted concepts of the equivalent dose H and groups of critical organs. From the analysis it follows that the committed effective dose is a linear transformation of the intake, linking these two quantities by the dose coefficient, which does not depend on the time during which the intake occurred, and reflects certain exposure conditions of the radionuclide intake (intake routes, parameters of aerosols and type of radionuclide compounds). It was also shown that the reference value of the function z(t) linking the measured value of activity in an organ (tissue) or in excretion products with the committed effective dose for a reference person, which is introduced for the first time in the publications of the ICRP OIR 2015-2019, makes it possible to standardize the method of measuring the normalized value of the effective dose. Based on the comparison of the predicted values of the lung and daily urine excretion activities following constant chronic inhalation intake of insoluble plutonium compounds at a rate equal annual limit of intake (ALI) during the period of occupational activity 50 years it was shown that the modern biokinetic models give a slightly lower level (on average 2 times) of the lungs exposure compared to the models of the previous generation and a proportionally lower level (on average 1.4 times) of plutonium urine excretion for the standard type of insoluble plutonium compounds S. However, for the specially defined insoluble plutonium compound, PuO2, the level of plutonium urine excretion differs significantly downward (on average 11.5 times) compared to the models of the previous generation. Conclusion: With the practical implementation of new ICRP OIR models, in particular for PuO2 compounds, additional studies should be carried out on the behavior of insoluble industrial plutonium compounds in the human body. Besides, additional possibilities should be used to determine the intake of plutonium by measuring in the human body the radionuclide Am-241, which is the Pu-241 daughter. To determine the plutonium urine excretion, the most sensitive measurement techniques should be used, having a decision threshold about fractions of mBq in a daily urine for S-type compounds and an order of magnitude lower for PuO2 compounds. This may require the development and implementation in monitoring practice the plutonium-DTPA Biokinetic Model.

CURRENT PROBLEMS OF NORMALIZATION OF PHYSICAL FACTORS IN THE OPERATION OF COMPUTER EQUIPMENT

Analysis of national and international databases on the safety of physical factors. Non-regulatory working conditions of computer users are largely due to the lack of national sanitary norms and rules for the safe operation of computer equipment. Current international standards relate to the radiative properties of technical means and do not consider the conditions in the workplace. It is shown that general standards on maximum permissible levels of physical factors are unacceptable for their application in the field of user safety due to high maximum permissible levels of electromagnetic fields, infrasound, electrostatic fields, etc. In addition, there are significant differences in the various current regulations regarding limit levels and methods for determining the integrated electromagnetic load. When developing sanitary norms for the safety of users of computer equipment, the dependence of air quality on the aeroionic composition on the presence of surface electrophysical charges on polymer surfaces and models of technical means and means of air cooling should be taken into account. It is advisable to regulate the use of artificial air ionization devices. Given the relatively low levels of electromagnetic fields in the workplace of users, it is necessary to regulate the ways of controlling the levels of electromagnetic fields with acceptable errors. Given the impact of unstable operation of technical ways on the psychomatic state of users in the process of developing the relevant standard, it is necessary to take into account the stable operation of equipment by increasing the levels of electromagnetic compatibility of equipment.

Determination of Some Heavy Metals in Cultured Nile Tilapia (Oreochromis niloticus) in Western Kordofan State, Sudan

The current study was conducted in two different localities have been selected in Western Kordofan State (Elsonout and Abu-zabad Localities) to evaluate some heavy metals concentrations (Copper, Cadmium, Zinc, and Lead) in three parts (liver, gills and muscles) of Nile Tilapia (Oreochromis niloticus) cultured in Dams, also to evaluate the same heavy metals concentrations in Dams water where Nile Tilapia is cultured. The evaluation was included the correlation of heavy metals accumulation between fish organs and water samples were compared. Finally, the results were compared with recommended levels by FAO, WHO and other international organizations. A total of 54 samples has been taken from marketable size Nile Tilapia parts (gills; livers and muscles) and subjected to analysis of heavy metals accumulations. Also, a total of 18 water samples were taken from Dams (shallow, middle and deep water). The data was subjected to SPSS using ANOVA. The findings of this work were revealed that, there were a highly significant differences (P≤0.01) in all heavy metals among gills, liver and muscles of Nile Tilapia cultured in Dams. And there was a highly significant difference (P≤0.01) in all heavy metals among gills, liver and muscles of Nile Tilapia according to localities. Anyway, when compared fish organs; we found that, gills were recorded the maximum figures in all heavy metals followed by livers and the minimum figures were recorded by muscles. The results of this study were in the permissible levels recommended by international organizations.

Designing of Fabric Reinforced Polymer in the Assessment of Sorption Capacity of Mussel Shell Powder for Divalent Ion: GIS Mapping and Statistical Studies

This paper discusses the efficiency of acid modified mollusc shell powder in adsorbing Zn(II) ions from synthetic wastewater and actual wastewater samples discharged from electroplating industries. The chemically treated adsorbent was characterized in terms of structure and surface properties. The parameters such as, size of the sorbent particles, dosage, initial Zn(II) concentration, temperature, contact time pH and temperature were varied for optimization using batch studies. The adsorbate-adsorbent system was studied by Langmuir, Freundlich, Tempkin and DKR isotherms. The adsorption experiments were conducted in a column packed with the acid modified mollusc shell powder. Further, real wastewater samples having Zn(II) concentration higher than the permissible levels were collected from the industrial belt in Coimbatore, to assess the potential of the bio adsorbent. A fiber reinforced polymer fabricated with the adsorbent material installed at the effluent discharge plants achieved 100% Zn(II) removal from electroplating wastewaters. Statistical analysis performed using SPSS software showed significant correlation among the input parameters and the analytical results post-adsorption.