Aspects of Tests and Assessment of Filtering Materials Used for Respiratory Protection Against Bioaerosols. Part II: Sweat in the Environment,Microorganisms in the Form of a Bioaerosol

The second part of the article presents the results of a study of antimicrobial activity of filter nonwovens with an addition of biocides, as a function of the presence of sweat in the environment and the method of microbe deposition on a nonwoven in the form of a liquid and a bioaerosol. At the same time, the filtration efficiency of nonwovens against microorganisms in the form of a bioaerosol was tested with the dynamic method. The results showed that the addition of sweat on the surface of a nonwoven resulted in an insignificant decrease of biological activity that still remained high. Moreover, an active nonwoven showed biostatic and biocidal activity only when microbes were deposited on the surface in the form of a solution. The nonwoven did not show any biological activity after deposition of microorganisms with the dynamical method in the form of a bioaerosol.     

Determining Attenuation of Impulse Noise With an Electrical Equivalent of a Hearing Protection Device

Determining the effectiveness of impulse noise attenuation with hearing protection devices (HPDs) is an important part of their selection. Measuring impulse noise parameters under an HPD would involve exposing subjects to impulses with a high peak sound pressure level. This paper presents a computational method of determining impulse noise parameters under the cups of earmuffs. Calculations are done using the transfer function of earmuffs, determined with Shaw’s electrical equivalent of an HPD, taking into account the design parameters of earmuffs. The developed method was used for calculations in the presence of impulse noise generated by gunshots. To verify the computational method, the results of these calculations were compared with the results of measurements.     

A Contribution to the Study of the Antidust Respirators’ Real Performance

In most industrial enterprises, hazardous factors are present in quantities exceeding permissible levels. Such a situation requires using antidust respiratory protection. It has been suggested, however, that filters for respirators are not assessed properly and that lab results might not be related to real filtering efficiency in industry. This article contains test results of some commercially available filtering half-masks, including the effect of loading with real dust, high humidity, high temperature, and a combination of loading with dust and high humidity on the half-masks’ performance. The results show that the effect of these factors is considerable and that a combination of loading with silica dust and exposing to high humidity can cause a complete loss of performance.     

Application of Neural Networks in Active Noise Reduction Systems

Active noise reduction systems based on a control unit in the form of a finite impulse response filter assume the linearity of every single component. Neural networks, which have so far been seldom used in this field, are a kind of a filter with the ability to project nonlinear characteristics of an active noise reduction system. This paper presents some simulation research studies of active noise reduction systems based on neural networks. Also presented are results of the operation of systems with different levels of complexity as well as the influence of different parameters of a neural network and of the system itself on those results.     

The effect of the corticosteroid hormone cortexolone on the metabolites produced during phenanthrene biotransformation in Cunninghamella elegans

The metabolism of phenanthrene and the mammalian corticosteroid hormone cortexolone by the fungus Cunninghamella elegans was studied. The amounts of the cortexolone transformation products, cortisol and epicortisol, were affected by the presence of phenanthrene. Approximately 40% more cortisol was produced by C. elegans in cultures with phenanthrene. In contrast, epicortisol formation decreased. C. elegans transformed phenanthrene to phenanthrene trans-1,2-,3,4-, and 9,10-dihydrodiols, phenols, diphenols (diols) and glucoside conjugates of 1-, 2-, 3-, 4-, and 9-phenanthrols. Almost all of the phenanthrene initially added was metabolized to ethyl acetate extractable metabolites. In the mycelia and culture medium extracts, phenanthrol glucosides represented 80% and 94% of the total metabolites, respectively. The major metabolite was the glucoside conjugate of 1-phenanthrol. The presence of cortexolone affected the biodegradation of phenanthrene by decreasing the amounts of phenanthrene metabolites compared to control cultures.     

The degradation of the cyanobacterial hepatotoxin nodularin (NOD) by UV radiation

This study investigates the decomposition of NOD by UV irradiation. Water solutions of pure NOD and NOD-containing Nodularia extract as well as Nodularia filaments collected on filters were exposed to UV-A, UV-B, and white fluorescent light (VIS) during 48 h experiments. In VIS, the toxin was fairly stable and only 3.8-4.6% of the original degraded. UV-B had the most pronounced effect on the NOD degradation rate. In the experiment, the overall loss of NOD was 0.27 and 0.77 micro g ml(-1)day(-1) for the solution of pure toxin and Nodularia extract and 0.28 micro g day(-1) for Nodularia filaments. Comparison of UV-B degradation rate in water and methanol extracts revealed higher stability of NOD in methanol. This might suggest that some hydrophobic components of Nodularia cell play a protective role against UV radiation. Additionally, chemical (LC-MS/MS) and biochemical (ELISA and PPIA) assays were employed to characterize the UV degradation products. LC-MS/MS analyses showed that in UV-B exposed sample, apart from NOD, there were three other compounds with molecular ion at m/z at 825.4. The fragmentation pattern of the ion was the same for all four compounds suggesting that they are geometrical isomers of NOD. The major degradation product, with a local absorption maximum at 242 nm, was active in both biochemical assays.     

Lessons from Norovirus Outbreak in Warsaw,Poland, December 2012

Efficient foodborne outbreak investigations are important for identification of gaps in food safety and public health practice. This article reports on an investigation of a gastroenteritis outbreak linked to catering food following a Christmas reception at the National Institute of Public Health-National Institute of Hygiene (NIPH-NIH) in Warsaw in December 2012. Of 192 employees eating food at the catering event, 97 (50.5 %) developed symptoms. Persons eating dishes with recipes containing frozen carrots were five times more likely to develop gastrointestinal symptoms compared to those who did not eat carrots. Laboratory analysis identified norovirus in stool samples taken from symptomatic persons. Leftover food was not available for testing. The investigators did not collect stool specimens from food handlers and did not conduct trace backs for the suspected food ingredients. This investigation underlines the need for a revision of an existing procedures and importance of their complementation with detailed instructions for the local public health authorities for effective completion of foodborne outbreaks investigations in Poland.     

Occurrence of Norovirus and Hepatitis A Virus in Wild Mussels Collected from the Baltic Sea

The aim of the study was to define the occurrence of human noroviruses of genogroup I and II (NoV GI and NoV GII) and hepatitis A virus (HAV) in the Baltic Sea mussels. The shellfish samples were taken at the sampling sites located on the Polish coast. In total, 120 shellfish were tested as pooled samples using RT-PCR and hybridisation with virus specific probes. NoV GI was detected in 22 (18.3 %), NoV GII in 28 (23.3 %), and HAV in 9 (7.5 %) of the shellfish. The nucleotide sequence analysis of the detected NoV GII strains showed a 97.3–99.3 % similarity to GII.4 virus strain. This is the first report describing the NoV and HAV occurrence in wild Baltic mussels and their possible role as bioindicators of seawater contamination with human enteric viruses.     

Snowpack-stored atmospheric surface-active contaminants traced with snowmelt water surface film rheology

Environmental Science and Pollution Research - The aim of the study was to quantify the adsorptive and thermo-elastic properties of snowmelt water surface films and their spatial-temporal evolution...     

An evaluation of selected chemical,biochemical, and biological parameters of soil enriched with vermicompost

Environmental Science and Pollution Research - The aim of this study was to assess the changes in chemical and microbial properties and enzymatic activity of soil enriched with vermicompost derived...