Liter Of Air Research Articles

Optimizing the Sensitivity of Biological Particle Detectors through Atmospheric Particle Analysis According to Climatic Characteristics in South Korea.

Biological agents used in biological warfare or bioterrorism are also present in bioaerosols. Prompt identification of a biological weapon and its characteristics is necessary. Herein, we optimized an environmentally adaptive detection algorithm that can better reflect changes in the complex South Korean environment than the current models. The algorithm distinguished between normal and biological particles using a laser-induced fluorescence-based biological particle detector capable of real-time measurements and size classification. We ensured that the algorithm operated with minimal false alarms in any environment by training based on experimental data acquired from an area where rainfall, snow, fog and mist, Asian dust, and water waves on the beach occur. To prevent time and money wastage due to false alarms, the detection performance for each level of sensitivity was examined to enable the selection of multiple sensitivities according to the background, and the appropriate level of sensitivity for the climate was determined. The basic sensitivity was set more conservatively than before, with a 3% alarm rate at 20 agent-containing particles per liter of air (ACPLA) and a 100% alarm rate at 63 ACPLA. The reliability was increased by optimizing five variables. False alarms did not occur in situations where no alarm was unnecessary.

Essential Oils from Artemisia herba alba Asso., Maticaria Recutita L., and Dittrichia Viscosa L. (Asteraceae): A Promising Source of Eco-Friendly Agents to Control Callosobruchus maculatus Fab. Warehouse Pest

Callosobruchus maculatus (Fab.) (C. maculatus) is one of the major pests of legume seeds in storage causing significant damage, leading to food insecurity and low income for farmers. This work was planned to develop eco-friendly agents from essential oils of Artemisia herba alba Asso. (AEO), Maticaria Recutita L. (MEO), and Dittrichia Viscosa L. (DEO) to control C. maculatus. To achieve this goal, essential oils (EOs) were extracted by hydro-distillation using Clevenger apparatus before being characterized by GC-MS. EOs were used for testing purposes using three different tests, namely, inhalation toxicity, contact toxicity, and repellency tests. GC-MS analysis of EOs showed the presence of 16 potentially active compounds in AEO and 38 in MEO, whilst 15 compounds were identified in DEO. AEO was higher in thujone (57.6%) and chrysanthenone (11.8%). Santolina alcohol (40.7%) and germacrene D (8.9%) were the major compounds identified in MEO, whereas isocostic acid (72.3%) was the chief compound of DEO. The obtained findings showed that the studied EOs showed considerable insecticidal activity against C. maculatus with a lethal dose (LC50) of 3.78, 8.86, and 14.34 μL/1 liter of air by AEO, MEO, and DEO, respectively. At 1 μL/1 liter of air, the oviposition reduction rate was 90.02%, 70.65%, and 48.23% by AEO, MEO, and DEO, respectively, whereas the emergence reduction rate was 87.32%, 60.08%, and 32.24% by AEO, MEO, and DEO, respectively. With increasing doses up to 20 μL/L, the reduction of individual emergence reached 98.8% by AEO of 24 h after treatment. AEO, MEO, and DEO showed significant repellent effects against adults of C. maculatus with repulsion percentages of 60.83%, 50.83%, and 72.5%, respectively. The outcome of this work suggests that the essential oils of the studied plants, particularly Artemisia herba alba Asso. oils, can constitute a natural and environmentally friendly alternative to develop new bioinsecticides for the control of C. maculatus.

Background Free‐Tropospheric Ice Nucleating Particle Concentrations at Mixed‐Phase Cloud Conditions

AbstractClouds containing ice are vital for precipitation formation and are important in determining the Earth's radiative budget. However, primary formation of ice in clouds is not fully understood. In the presence of ice nucleating particles (INPs), the phase change to ice is promoted, but identification and quantification of INPs in a natural environment remains challenging because of their low numbers. In this paper, we quantify INP number concentrations in the free troposphere (FT) as measured at the High Altitude Research Station Jungfraujoch (JFJ), during the winter, spring, and summer of the years 2014–2017. INPs were measured at conditions relevant for mixed‐phase cloud formation at T = 241/242 K. To date, this is the longest timeline of semiregular measurements akin to online INP monitoring at this site and sampling conditions. We find that INP concentrations in the background FT are on average capped at 10/stdL (liter of air at standard conditions [T = 273 K and p = 1013 hPa]) with an interquartile range of 0.4–9.6/stdL, as compared to measurements during times when other air mass origins (e.g., Sahara or marine boundary layer) prevailed. Elevated concentrations were measured in the field campaigns of 2016, which might be due to enhanced influence from Saharan dust and marine boundary layer air arriving at the JFJ. The upper limit of INP concentrations in the background FT is supported by measurements performed at similar conditions, but at different locations in the FT, where we find INP concentrations to be below 13/stdL most of the time.

Characterization of 41Ar production in air at a PET cyclotron facility

In the production of Positron Emission Tomography (PET) nuclides at a medical cyclotron facility [Formula: see text]Ar (T[Formula: see text] = 109.34 m) is produced by the activation of air due to the neutron flux, according to the [Formula: see text]Ar(n, [Formula: see text])[Formula: see text]Ar reaction. In this work, we describe a relatively inexpensive and readily reproducible methodology of air sampling that can be used for quantification of [Formula: see text]Ar during the routine production of PET nuclides. We report the results of an extensive measurement campaign in the cyclotron bunker and in the ducts of the ventilation system, before and after final filtering of the extracted air. Air Samples were analyzed using a gamma-ray spectrometry system equipped with HPGe detector, with proper correction of the efficiency calibration to account for the samples density. The results of measurement were then used to evaluate the Total Effective Dose (TED) to the population living in the surrounding areas, due to routine emissions in the operation of the cyclotron. The average [Formula: see text]Ar saturation yield per one liter of air emitted in the environment resulted to be (0.044 ± 0.007) Bq/([Formula: see text]A ⋅ dm3). The maximum value of TED for the critical group of the population, even considering an overestimated workload, was less than 0.19 [Formula: see text]Sv/year, well below the level of radiological relevance.

A collection system for dry solid residues from exhaled breath for analysis via atomic force microscopy

Exhaled air contains sub-micron droplets of lung liquid, which potentially bear biomarkers of lung diseases. After dehydration they form dry residue particles (DRPs). As a first step in developing techniques to characterize individual DRPs, a new electrostatic collector was designed in which DRPs are charged within a unipolar corona charger, concentrated in a cone funnel, and deposited onto a limited area of a highly oriented pyrolytic graphite surface. The collector captures 80%–90% of DRPs at an optimal flow rate of 0.15 l min−1. Atomic force microscopy (AFM) revealed flattened round particles 20–50 nm high, with notable protrusions at their surface suggestive of an inhomogeneous internal structure. Exposure to humid air resulted in the DRPs spreading over the surface, with a 50%–200% decrease in their heights and an increase in their lateral dimensions so that their volume decreased by only 10% ± 3%. Exposure to saturated chloroform vapor resulted in drainage of 10%–15% of the DRP volume (presumably lipids), forming collar-shaped rings around each particle but leaving the core size and structure unchanged. AFM measurements combined with laser counter measurements of the DRP concentrations were used to estimate that one liter of air exhaled by volunteers contained less than 100 pg of dry residue material.

The Use of Planting Media and Application of Leaf Fertilizer on the Growth and Yield of Mustard (Brassica Junea L.) in the Casino (Verticulture) Planting System

Nowadays land is being limited by development. Therefore, it is necessary to apply agri- cultural technology that can be utilized by land such as casino (verticulture) planting sys- tems. This study discusses the use of planting media and the application of leaf fertilizer on the growth and yield of mustard (Brassica juncea L.). The study was conducted in Pangkemiri Village, Tulangan District, Sidoarjo Regency from March to April 2015. This research involved factors using a group design (RBD) consisting of 2 factors, factor 1 using planting media consisting of water hyacinth (K1) ), bagasse (K2), banana stems (K3). Factor 2 is the use of a dose of leaf fertilizer consisting of: leaf fertilizer (L1), a dose of 1gr / liter of air (L2), a dose of 1.5 gr / liter of air (L3), a dose of 2gr / liter (L4). From these two factors, 12 combinations were obtained and repeated 3 times. The results showed that the use of water hyacinth growing media and the use of leaf fertilizer dosage 1.5gr / liter air (K1L2) gave the best results on the variable plant length, number of leaves, total weight, and selling weight.

Ice Nucleating Particle Measurements at 241 K during Winter Months at 3580 m MSL in the Swiss Alps

Abstract Ice nucleating particle (INP) concentrations were measured at the High Altitude Research Station Jungfraujoch, Switzerland, 3580 m above mean sea level during the winter months of 2012, 2013, and 2014 with the Portable Ice Nucleation Chamber (PINC). During the measurement periods, the research station was mostly located in the free troposphere, and particle concentrations were low. At temperature T = 241 K, INP concentrations in the deposition regime [relative humidity with respect to water (RHw) = 93%] were, on average, below 1.09 per standard liter of air (stdL−1; normalized to 1013 hPa and 273 K) and 4.7 ± 8.3 stdL−1 in the condensation regime (RHw = 103%) in winter 2014. The deployment of a particle concentrator upstream of PINC decreased the limit of detection (LOD) by a factor of 3 compared to earlier measurements. The authors discuss a potential bias of INP measurements toward higher concentrations if data below the LOD are disregarded and thus recommend reporting subLOD data in future publications. Saharan dust and more local, basaltic dust mixed with marine aerosol were found to constitute the dominant INP type. Bioaerosols were not observed to play a role in ice nucleation during winter because of their low concentration during this period. The INP concentrations at Jungfraujoch are low in comparison to other studies of INP at this temperature. This represents the first study addressing interannual variations of INP concentrations during winter at one location.

The Urgent Compelling Need to Swap on a Global Scale from Indirect Mouse Calorimetry (IMC) Towards Direct Mouse Calorimetry (DMC) in Determining the Basal Metabolic Rate (BMR): A Principle of Proof Study

Mouse models are important in Biomedical- and Life Sciences. Recently it has been stated that the genetically engineered mouse models for contemporary Obesity and/or Type-2 diabetes (DM2) will in most cases deliver heavily metabolically abnormal animals due to changed gut microbiotics with increased anaerobic CO2 production. Therefore, it can be questioned if indirect calorimetry which it at this moment “the golden standard” in all mouse laboratories over the world, still can be practiced because it is dependent on the conversion factor Respiratory-Quotient (RQ-value: CO2/O2) for expressing energy expenditure into Heat production (HP) in [mW]. Direct calorimetry, however, can accurately quantify HP and thus Basal Metabolic Rate (BMR) in both metabolically normal and abnormal states. In this first manuscript we determined physical properties and characteristics of a former aquatic flow-through twin detection Setaram calorimeter used for measuring Basal Metabolic Rate of fish under adverse environmental conditions (anoxic-, hypoxic-, acid- environmental water). Our objective of this study was to determine if this Setaram calorimetric system with stainless steel vessel of 1 liter could be used in the physical medium air in order to measure energy expenditure in mouse models. This first [Technical note] describes the physical properties and characteristics in the medium water and air of this calorimetric set up. Characteristics of the calorimetric system in air were for the initial baseline over 80 minutes a heat flow of 13.44 ± 1.611 (mW) and for the end baseline over 175 minutes 14.95 ± 1.79 (mW) so the A¢ÂˆÂ†-Baseline (initial –end) was 13.44-14.95 = -1.51 (mW). The drifting baseline over the total experiment of 33h was (14.95 / 13.44) * 100% = 1.1124% with a drifting baseline per hour was 0.035 % per hour which are common values for twin detection Calvin calorimeters. We calculated based on the heat transfer characteristics from water to stainless steel (aquatic calorimeter) in combination with the specific heat capacity of water Cp-water of 4,1884 [kJ K-1] vs Cp-air is 0.001293 [kJ K-1] an aquatic time-constant τwater of 30.48 min vs τair or = 0.019605 min. Because the τair was so small deconvolution techniques (earlier successfully applied in water), correcting for the lag time of the system had no effect. This study also includes the first successful “principle of proof” pilot-experiment with one single mouse locked up for ≈ 14 h proves that measuring the energy expenditure with a single mouse in the 1 liter stainless steel calorimetric vessel in the medium air corresponds to measured values of wild strain mouse used in indirect calorimetry (IMC) (of ≈10 mW/g). A precondition was that in order to prevent suffocating of the mouse in the one liter vessel both vessel (Measurement and Reference: twin detection measurement were supplied with one liter of air per minute- with this former aquatic flow-through twin detection Setaram calorimeter. Although there is in Bio-calorimetry a switch to cell-, (sub)cellular, molecular and biomolecular interactions, this study with “whole animal” calorimetry proves that at the organismal level important fundamental questions are still unanswered and open related to the pathogenesis of human diseases like Obesity and metabolic related disorders like Type-2 Diabetes and more fundamental Life Sciences related processes like ‘ageing’. In addition, also the research area of nutraceuticals can be tested with DMC.

Experimental measurement and Monte Carlo assessment of Argon-41 production in a PET cyclotron facility

In a medical cyclotron facility, 41Ar (t1/2 = 109.34 m) is produced by the activation of air due to the neutron flux during irradiation, according to the 40Ar(n,γ)41Ar reaction; this is particularly relevant in widely diffused high beam current cyclotrons for the production of PET radionuclides. While theoretical estimations of the 41Ar production have been published, no data are available on direct experimental measurements for a biomedical cyclotron. In this work, we describe a sampling methodology and report the results of an extensive measurement campaign. Furthermore, the experimental results are compared with Monte Carlo simulations performed with the FLUKA code. To measure 41Ar activity, air samples were taken inside the cyclotron bunker in sealed Marinelli beakers, during the routine production of 18F with a 16.5 MeV GE-PETtrace cyclotron; this sampling thus reproduces a situation of absence of air changes. Samples analysis was performed in a gamma-ray spectrometry system equipped with HPGe detector. Monte Carlo assessment of the 41Ar saturation yield was performed directly using the standard FLUKA score RESNUCLE, and off-line by the convolution of neutron fluence with cross section data. The average 41Ar saturation yield per one liter of air of 41Ar, measured in gamma-ray spectrometry, resulted to be 3.0 ± 0.6 Bq/µA*dm3 while simulations gave a result of 6.9 ± 0.3 Bq/µA*dm3 in the direct assessment and 6.92 ± 0.22 Bq/µA*dm3 by the convolution neutron fluence-to-cross section.

Sterility maintenance study: Dynamic evaluation of sterilized rigid containers and wrapped instrument trays to prevent bacterial ingress

Sterilized packaging systems are designed to maintain the sterility of surgical instruments and devices from the time of sterilization until use. This study evaluated the effectiveness of rigid containers versus wrapped instrument trays, sterilized using North American sterilization protocols, to maintain a sterile internal environment poststerilization when challenged with aerosolized bacteria under dynamic environmental conditions. Using a custom aerosol chamber, 111 rigid containers of various durations of use (unused, used <5 years, used 5-9 years) and 161 wrapped trays using 3 grades of sterilization wrap were challenged with ~10(2) colony-forming units per liter of air containing aerosolized Micrococcus luteus with a count median particle size of 1 μm, while simultaneously experiencing air volume exchanges due to vacuum cycles-two 1-psi cycles, three 0.7-psi cycles, and three 0.4-psi cycles-to simulate air exchange events occurring during the sterilization, transportation, and storage of sterilized instrument trays in health care facilities. Of 111 rigid containers tested, 97 (87%) demonstrated bacterial ingress into the container. Of 161 wrapped trays, 0 (0%) demonstrated bacterial ingress into the tray. Contamination rates of rigid containers increased significantly with increasing duration of use. In this study using a dynamic bacterial aerosol challenge, sterilized wrapped trays demonstrated significantly greater protection than sterilized rigid containers against the ingress of airborne bacteria.

Composition, Diffusion, and Antifungal Activity of Black Mustard (Brassica nigra) Essential Oil When Applied by Direct Addition or Vapor Phase Contact

In this study, we characterized the essential oil (EO) of black mustard (Brassica nigra) and quantified its antimicrobial activity, when applied by direct contact into the liquid medium or by exposure in the vapor phase (in laboratory media or in a bread-type product), against the growth of Aspergillus niger, Aspergillus ochraceus, or Penicillium citrinum. Allyl-isothiocyanate (AITC) was identified as the major component of B. nigra EO with a concentration of 378.35 mg/ml. When B. nigra EO was applied by direct contact into the liquid medium, it inhibited the growth of A. ochraceus and P. citrinum when the concentration was 2 μl/ml of liquid medium (MIC), while for A. niger, a MIC of B. nigra EO was 4 μl/ml of liquid medium. Exposure of molds to B. nigra EO in vapor phase showed that 41.1 μl of B. nigra EO per liter of air delayed the growth of P. citrinum and A. niger by 10 days, while A. ochraceus growth was delayed for 20 days. Exposure to concentrations ≥47 μl of B. nigra EO per liter of air (MIC) inhibited the growth of tested molds by 30 days, and they were not able to recover after further incubation into an environment free of EO (fungicidal effect). Adsorbed AITC was quantified by exposing potato dextrose agar to B. nigra EO in a vapor phase, exhibiting that AITC was retained at least 5 days when testing EO at its MIC or with higher concentrations. Mustard EO MIC was also effective against the evaluated molds inhibiting their growth for 30 days in a bread-type product when exposed to EO by vapor contact, demonstrating its antifungal activity.

Healthy worker survivor bias in the Colorado Plateau uranium miners cohort.

Cohort mortality studies of underground miners have been used to estimate the number of lung cancer deaths attributable to radon exposure. However, previous studies of the radon-lung cancer association among underground miners may have been subject to healthy worker survivor bias, a type of time-varying confounding by employment status. We examined radon-mortality associations in a study of 4,124 male uranium miners from the Colorado Plateau who were followed from 1950 through 2005. We estimated the time ratio (relative change in median survival time) per 100 working level months (radon exposure averaging 130,000 mega-electron volts of potential α energy per liter of air, per working month) using G-estimation of structural nested models. After controlling for healthy worker survivor bias, the time ratio for lung cancer per 100 working level months was 1.168 (95% confidence interval: 1.152, 1.174). In an unadjusted model, the estimate was 1.102 (95% confidence interval: 1.099, 1.112)-39% lower. Controlling for this bias, we estimated that among 617 lung cancer deaths, 6,071 person-years of life were lost due to occupational radon exposure during follow-up. Our analysis suggests that healthy worker survivor bias in miner cohort studies can be substantial, warranting reexamination of current estimates of radon's estimated impact on lung cancer mortality.

Variability in EIT Images of Lung Ventilation as a Function of Electrode Planes and Body Positions.

This study is aimed at investigating the variability in resistivity changes in the lung region as a function of air volume, electrode plane and body position. Six normal subjects (33.8 ± 4.7 years, range from 26 to 37 years) were studied using the Sheffield Electrical Impedance Tomography (EIT) portable system. Three transverse planes at the level of second intercostal space, the level of the xiphisternal joint, and midway between upper and lower locations were chosen for measurements. For each plane, sixteen electrodes were uniformly positioned around the thorax. Data were collected with the breath held at end expiration and after inspiring 0.5, 1.0, or 1.5 liters of air from end expiration, with the subject in both the supine and sitting position. The average resistivity change in five regions, two 8x8 pixel local regions in the right lung, entire right, entire left and total lung regions, were calculated. The results show the resistivity change averaged over electrode positions and subject positions was 7-9% per liter of air, with a slightly larger resistivity change of 10 % per liter air in the lower electrode plane. There was no significant difference (p>0.05) between supine and sitting. The two 8x8 regions show a larger inter individual variability (coefficient of variation, CV, is from 30% to 382%) compared to the entire left, entire right and total lung (CV is from 11% to 51%). The results for the global regions are more consistent. The large inter individual variability appears to be a problem for clinical applications of EIT, such as regional ventilation. The variability may be mitigated by choosing appropriate electrode plane, body position and region of interest for the analysis.

Characterization of a Combined Treatment with Alpha-Lipoic Acid for the Control of Enzymatic Browning in Fresh-Cut Golden Delicious Apples

Enzymatic browning is the main cause of quality loss in minimally processed fresh-cut apples and this study was aimed to control it by evaluating the use of a treatment with α-lipoic acid and ascorbic acid on Golden Delicious apples. Also hexanal, an effective natural enhancer of apple odor, was added to the treatment. At the end of the preservation period, colorimetric analysis demonstrated that α-lipoic acid exerts an anti-browning effect comparable with that of ascorbic acid about 60 times more concentrated and, moreover, chemical assays demonstrated its synergistic interaction with this substance. The application of the “antibrowning mix” does not substantially change the volatile profile of the apple slices while the addition of hexanal (0.076 mmol per liter of air) improves it primarily with an increased production of hexyl acetate (about 86% of the average aromatic component), without modifying the fruit respiration.

First Finding of Ostreopsis cf. ovata Toxins in Marine Aerosols

Since the late 1990s, a respiratory syndrome has been repetitively observed in humans concomitant with Ostreopsis spp. blooms (mainly O. cf. ovata) in the Mediterranean area. Previous studies have demonstrated that O. cf. ovata produces analogues of palytoxin (ovatoxins and a putative palytoxin), one of the most potent marine toxins. On the basis of the observed association between O. cf. ovata blooms, respiratory illness in people, and detection of palytoxin complex in algal samples, toxic aerosols, containing Ostreopsis cells and/or the toxins they produce, were postulated to be the cause of human illness. A small scale monitoring study of marine aerosol carried out along the Tuscan coasts (Italy) in 2009 and 2010 is reported. Aerosols were collected concomitantly with O. cf. ovata blooms, and they were analyzed by both PCR assays and LC-HRMS. The results, besides confirming the presence of O. cf. ovata cells, demonstrated for the first time the occurrence of ovatoxins in the aerosol at levels of 2.4 pg of ovatoxins per liter of air. Given the lack of toxicological data on palytoxins by inhalation exposure, our results are only a first step toward a more comprehensive understanding of the Ostreopsis-related respiratory syndrome.

Artificial and Biological Particles in the Springtime Atmosphere

This study focused on a comprehensive and detailed interpretation for the springtime air quality influenced by both artificial (particulate matter (PM) and asbestos) and biological (pollen) sources in Fukuoka Prefecture, Japan. An intensive measurement of PM was conducted at four characteristic sites (i.e., a heavy traffic area, a residential area, an industrial area, and a desolate area) in the Fukuoka Prefecture during spring of 2007. Analysis of major ionic species in <TEX>$PM_{2.5}$</TEX> was performed by an Ion Chromatography, and asbestos and pollen were identified by Scanning Electron Microscopy with an energy dispersive X-ray spectrometer (EDX). <TEX>$PM_{2.5}$</TEX> concentration (<TEX>$65.3{\mu}gm^{-3}$</TEX>) measured in an industrial area (site C) was extraordinarily high compared to those monitored in other areas; it greatly exceeded the Japan's <TEX>$PM_{2.5}$</TEX> criteria (a daily average of <TEX>$35{\mu}gm^{-3}$</TEX>). NOAA's HYSPLIT dispersion model suggests that this high level of <TEX>$PM_{2.5}$</TEX> monitored at site C is unlikely to affect the Asian continent. The ambient concentrations of <TEX>$PM_{2.5}$</TEX>-related anions (<TEX>$NH_4{^+}$</TEX>, <TEX>$NO_3{^-}$</TEX>, and <TEX>$SO_4{^{2-}}$</TEX>) and their relative contributions to <TEX>$PM_{2.5}$</TEX> were also investigated in four study areas. The concentrations of these major water-soluble ions exhibit not only strong spatial dependence but also different ratios to each other. Asbestos fiber (crocidolite and amosite) concentration values changed in the range of 2.5 to 14.4 f per liter of air. The number of pollen grains showed that Cedar ranked higher in concentration than other types of pollen, with the maximum concentration at site A.

Measurement of Radon Concentration of Air Samples and Estimating Radiation Dose from Radon in SARI Province

Exposure to radon is the second leading cause of lung cancer after smoking. Radon is an odorless, tasteless and invisible gas produced by the decay of naturally occurring uranium in soil and water. The amount of radon in the air is measured in picocuries per liter of air, or pCi/L. There are many kinds of low-cost do-it-yourself radon test kits you can get through the mail and in some hardware stores and other retail outlets. In this study to measure radon in homes in the province of Sari by dosimeters DOSEman (SARAD GmbH company). Population of the city of Sari 495,369 people and the urban population of village of forty to sixty is the degree of concentration of 116.5 people/ km 2 . A percentage of the total household population of Sari in areas geographically different samples is selected. Radon measuring in four different seasons (in one year) at home for sampling was done. Sensors 60-minute room bedroom or living at an altitude of 50 to 90 cm from the floor, away from windows and sunlight placed howe dose rate and radon gas in homes has been measured. Amount of radon in your home in spring 28.615Bq m-3, in summer Bq m-3 27.20, in autumn 27.07Bq m-3 in winter Bq m-3 36.95 measures. Both dose levels in spring .0032 μSv, in the summer 0.026 μSv, in the autumn 0.037μSv in winter 0.056 μSv is measured. Annual dose equivalent to approximately 0.0151μSv / year .Radon measurement results show that the average radon concentration is higher in winter than other seasons. This difference could be due to lack of air movement and stillness, and the dose of radon indoors in winter.

Sensory Effects of Hexanal Vapor on Fresh‐Cut Slices of Golden Delicious Apples

Hexanal is a natural antimicrobial molecule that characterizes apples aroma. In this paper, the sensory effects of hexanal, as a component of packaging atmosphere, on fresh sliced Golden Delicious apples after storage at 4 °C for 8 d were evaluated. In particular, a colorimetric analysis of slices treated with different concentrations of hexanal vapor (coming from 3.040 to 0.076 mmol of liquid aldehyde per liter of air) fixed at 0.076 mmol/L the amount of hexanal in evaluating sensory effects in the subsequent analysis. Color and texture evaluation of slices by Two-out-of-Five method did not highlight any significant difference between treatment and control. The results from olfactory evaluation showed instead that treated samples had an intense odor compared with those untreated (P < 0.001). A significant difference between treatment and control was also highlighted during the flavor evaluation (P < 0.01); however, from the panelists' observations it emerged that such an effect would work negatively. The positive effect of the tested dose of hexanal on the odor of Golden Delicious slices and its flavor acceptability were verified by using regular apple consumers. A significant preference (P < 0.001) for the odor of treated apple slices came out, so the small dose of hexanal intensifies the odor of apples pleasantly. The different flavor of treated samples was not identified by the consumers, who altogether expressed positive judgments about it. This suggests the nicety of this difference that in the absence of an untreated reference sample is very difficult to detect.

Generation of airborne Listeria innocua from model floor drains.

Listeria monocytogenes can colonize floor drains in poultry processing and further processing facilities, remaining present even after cleaning and disinfection. Therefore, during wash down, workers exercise caution to avoid spraying hoses directly into drains in an effort to prevent the escape and transfer of drain microflora to food contact surfaces. The objective of this study was to examine the extent to which an inadvertent water spray into a colonized floor drain can cause the spread of airborne Listeria. Listeria innocua was used to inoculate a polyvinyl chloride model floor drain, resulting in approximately 10(8) cells per ml of phosphate-buffered saline and 10(4) attached cells per square centimeter of inner surface. Each model drain was subjected to a 2-s spray of tap water at 68.9 kPa from a distance of 1 m. Drains were sprayed while filled and again after emptying. Airborne cells were collected by using sedimentation plates containing Listeria selective agar which were placed on the floor and walls of a contained room at incremental horizontal and vertical distances of 0.6, 1.2, 2.4, or 4.0 m from the drain. Sedimentation plates were exposed for 10 min. A mechanical sampler was used to also collect air by impaction on the surface of Listeria selective agar to determine the number of cells per liter of air. The experiment was conducted in triplicate rooms for each of four replications. L. innocua was detected on sedimentation plates on the floor as far as 4.0 m from the drain and on walls as high as 2.4 m above the floor and 4 m from the drain. A 2-s spray with a water hose into a contaminated drain can cause airborne spread of Listeria, resulting in the potential for cross-contamination of food contact surfaces, equipment, and exposed product.

Antifungal activity evaluation of Mexican oregano (Lippia berlandieri Schauer) essential oil on the growth of Aspergillus flavus by gaseous contact.

The antifungal activity of Mexican oregano (Lippia berlandieri Schauer) essential oil by gaseous contact on the growth of Aspergillus flavus at selected essential oil concentrations (14.7, 29.4, 58.8, or 117.6 μl of essential oil per liter of air) and temperatures (25, 30, or 35°C) was evaluated in potato dextrose agar formulated at water activity of 0.98 and pH 4.0. Mold growth curves were adequately fitted (0.984 < R(2) < 0.999) by the modified Gompertz model. The effect of the independent variables (concentration of essential oil and temperature) on the estimated model parameters (reciprocal of growth rate [1/ν(m)] and lag time [λ]) were evaluated through polynomial equations. Both ν(m) and λ were significantly (P < 0.05) affected by the independent variables; ν(m) decreased and λ increased as essential oil concentration increased and temperature decreased, which suggests that Mexican oregano essential oil retards or inhibits mold germination stage. Further, minimum fungistatic and fungicide essential oil concentrations at 30 and 35°C were determined. Mexican oregano essential oil applied in gas phase exerts important antifungal activity on the growth of A. flavus, suggesting its potential to inhibit other food spoilage molds.