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1.
ACS Appl Mater Interfaces ; 13(3): 4545-4552, 2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33459023

RESUMO

In this study, polydimethylsiloxane (PDMS)/polythiourethane (PTU) composite reinforced with tetrapodal shaped micro-nano ZnO particles (t-ZnO) was successfully produced by a versatile, industrially applicable polymer blending process. On the surface of this composite, PDMS is distributed in the form of microdomains embedded in a PTU matrix. The composite inherited not only good mechanical properties originating from PTU but also promising fouling-release (FR) properties due to the presence of PDMS on the surface. It was shown that the preferential segregation of PDMS domains at the polymer/air interface could be attributed to the difference in the surface free energy of PDMS and PTU. The PDMS microdomains at the PTU/air interface significantly reduced the barnacle adhesion strength on the composite. Both the pseudo- and natural barnacle adhesion strength on the composite was approximately 0.1 MPa, similar to that on pure PDMS. The pseudo-barnacle adhesion on reference surfaces AlMg3 and PTU reached approximately 4 and 6 MPa, respectively. Natural barnacles could not be removed intact from AlMg3 and PTU surfaces without breaking the shell, indicating that the adhesion strength was higher than the mechanical strength of a barnacle shell (approximately 0.4 MPa). The integrity of PDMS microdomains was maintained after 12 months of immersion in seawater and barnacle removal. No surface deteriorations were found. In short, the composite showed excellent potential as a long-term stable FR coating for marine applications.


Assuntos
Incrustação Biológica/prevenção & controle , Dimetilpolisiloxanos/química , Poliuretanos/química , Thoracica/citologia , Óxido de Zinco/química , Ar/análise , Animais , Nanopartículas/química , Transição de Fase , Propriedades de Superfície
2.
Chemosphere ; 2632021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33184521

RESUMO

The interfacial tracer test (ITT) conducted via aqueous miscible-displacement column experiments is one of a few methods available to measure air-water interfacial areas for porous media. The primary objective of this study was to examine the robustness of air-water interfacial area measurements obtained with interfacial tracer tests, and to examine the overall validity of the method. The potential occurrence and impact of surfactant-induced flow was investigated, as was measurement replication. The column and the effluent samples were weighed during the tests to monitor for potential changes in water saturation and flux. Minimal changes in water saturation and flux were observed for experiments wherein steady flow conditions were maintained using a vacuum-chamber system. The air-water interfacial areas measured with the miscible-displacement method completely matched interfacial areas measured with methods that are not influenced by surfactant-induced flow. This successful benchmarking was observed for all three media tested, and over a range of saturations. A mathematical model explicitly accounting for nonlinear and rate-limited adsorption of surfactant at the solid-water and air-water interfaces as well as the influence of changes in surface tension on matric potentials and flow was used to simulate the tracer tests. The independently-predicted simulations provided excellent matches to the measured data, and revealed that the use of the vacuum system minimized the occurrence of surfactant-induced flow and its associated effects. These results in total unequivocally demonstrate that the miscible-displacement ITT method produced accurate and robust measurements of air-water interfacial area under the extant conditions.


Assuntos
Ar/análise , Água/química , Adsorção , Benchmarking , Modelos Teóricos , Fenômenos Físicos , Porosidade , Tensão Superficial , Tensoativos/química
3.
Chemosphere ; 263: 127903, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32841873

RESUMO

In this study, seasonal/regional variations of Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs) and dioxin like-polychlorinated biphenyls in the ambient air were monitored for ten years (2008-2017) using a high volume air sampler. As a result of strict regulation enforced by Korea Ministry of Environment in 2008, PCDD/DFs concentrations in the ambient air decreased from 0.051 pg I-TEQ Sm-3 in 2009 to 0.014 pg I-TEQ Sm-3 in 2017 which was comparably associated with cut-down of their emission sources from 880.2 g I-TEQ Sm-3 in 2001 to 24.2 g I-TEQ Sm-3 in 2015; revealing that it was only 2.7% against that of 2001. In 2017, mean TEQ concentration level of PCDD/DFs in the air of South Korea was quite low in comparison to its ambient environmental standards of 0.6 pg I-TEQ Sm-3 for PCDD/DFs. Particularly, the sum of PCDD/DFs in the background revealed the lowest level, however, the fraction of octachlorodibenzodioxin among other isomers exposed at the highest level in this study, suggesting that the ambient air quality in the background being studied was severely and persistently impaired by inflowing unknown sources of any possible anthropogenic transboundary migratory air pollutants. Moreover, this study conducted the scientific analysis of the long-term variations in the ambient air and emission sources using principal component analysis. From this of 10 years long-term nationwide assessments for the PCDD/DFs and dl-PCBs in the ambient air, it is possible to prove that South Korean environmental policy to manage POPs has been successfully conducted for the last ten years.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Dibenzofuranos Policlorados/análise , Monitoramento Ambiental , Dibenzodioxinas Policloradas/análise , Ar/análise , Poluição do Ar/análise , Benzofuranos/análise , Dibenzofuranos/análise , Dioxinas/análise , Bifenilos Policlorados/análise , República da Coreia , Estações do Ano
5.
Ecotoxicol Environ Saf ; 201: 110833, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32535368

RESUMO

The largest mercury (Hg) mining district in the world is located in Almadén (Spain), with well-known environmental impacts in the surrounding ecosystem. However, the impact of mercury on the health of the inhabitants of this area has not been documented accordingly. This study aims to carry out a probabilistic human health risk assessment using Bayesian modeling to estimate the non-carcinogenic risk related to Hg through multiple exposure pathways. Samples of vegetables, wild mushrooms, fish, soil, water, and air were analyzed, and adult residents were randomly surveyed to adjust the risk models to the specific population data. On the one hand, the results for the non-carcinogenic risk based on Hazard Quotient (HQ) showed unacceptable risk levels through ingestion of Hg-contaminated vegetables and fish, with HQ values 20 and 3 times higher, respectively, than the safe exposure threshold of 1 for the 97.5th percentile. On the other hand, ingestion of mushrooms, dermal contact with soil, ingestion of water, dermal contact with water and inhalation of air, were below the safety limit for the 97.5th percentile, and did not represent a risk to the health of residents. In addition, the probabilistic approach was compared with the conservative deterministic approach, and similar results were obtained. This is the first study conducted in Almadén, which clearly reveals the high levels of human health risk to which the population is exposed due to the legacy of two millennia of Hg mining.


Assuntos
Exposição Ambiental/análise , Poluentes Ambientais/análise , Mercúrio/análise , Mineração , Adulto , Agaricales/química , Ar/análise , Animais , Teorema de Bayes , Ecossistema , Peixes/metabolismo , Humanos , Distribuição Aleatória , Medição de Risco , Solo/química , Espanha , Verduras/química
6.
Toxicol Lett ; 329: 20-25, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32380125

RESUMO

The aim of this study was to determine firefighter's exposure to benzene and toluene during a fire drill by monitoring air benzene and toluene, and their corresponding urinary metabolites. A liquid chromatography mass spectrometry (LC-MS) method with a minimal of sample preparation steps was developed for the benzene metabolite s-phenylmercapturic acid (SPMA) and the toluene metabolite s-benzylmercapturic acid (SBMA) in urine. Urine samples and air samples were collected from nine firefighters during and after a fire drill in a non-environmentally refurbished house. Benzene and toluene were detected in the air samples with a median concentration of 15.5 ppm and 3.2 ppm, respectively. The metabolites SPMA and SBMA was also detected in all urine samples donated ≥ three hours after the fire drill with a median concentration of 0.6 µg/g creatinine and 5.9 µg/g creatinine, respectively. By our knowledge, this is the first study detecting SPMA in urine from firefighters.


Assuntos
Acetilcisteína/análogos & derivados , Ar/análise , Benzeno/metabolismo , Bombeiros , Tolueno/metabolismo , Acetilcisteína/urina , Humanos , Masculino , Exposição Ocupacional , Fatores de Tempo
7.
Sci Rep ; 10(1): 5194, 2020 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-32251305

RESUMO

Explorative experiments were done to figure out differences in the emission of volatile organic compounds (VOCs) of not infested trees and trees infested by Anoplophora glabripennis (Asian longhorn beetle, ALB), a quarantine pest. Therefore, VOCs from some native insect species, Anoplophora glabripennis infested Acer, stressed Acer, healthy Acer, Populus and Salix were obtained by enrichment on adsorbents. Qualitative analysis was done by thermal desorption gas chromatography coupled with a mass selective detector (TD-GC/MS). Altogether 169 substances were identified. 11 substances occur from ALB infested or mechanically damaged trees i.e. stressed trees, but not from healthy trees. (+)-Cyclosativene, (+)-α-longipinene, copaene and caryophyllene are detectable only from ALB-infested Acer not from mechanically damaged or healthy Acer. However, these substances are also emitted by healthy Salix. 2,4-Dimethyl-1-heptene is among all tree samples exclusively present in the ambience of ALB-infested trees. It´s rarely detectable from native insect species' samples.


Assuntos
Acer/química , Besouros , Doenças das Plantas , Populus/química , Salix/química , Compostos Orgânicos Voláteis/análise , Ar/análise , Animais , Besouros/crescimento & desenvolvimento , Cromatografia Gasosa-Espectrometria de Massas , Larva , Oviposição
8.
Medicina (Kaunas) ; 56(2)2020 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-32033101

RESUMO

Background and objectives: The relationship between air pollen quantity and the sensitization of allergic patients is crucial for both the diagnosis and treatment of allergic diseases. Weather conditions influence the distribution of allergenic pollen and increases in pollen concentration may negatively affect the health of allergic patients. The aim of this study was to analyze the implementation of allergen immunotherapy with regard to air pollen concentration. Material and Methods: Here we examined the relationship between Betula air pollen concentration and the usage of Betula verrucosa allergen immunotherapy in Serbia. Examination covered the period from 2015 to 2018. Measurement of airborne pollen concentration was performed with Lanzoni volumetric pollen traps. The evidence of the usage of sublingual allergen immunotherapy (SLIT) was gathered from patients with documented sensitization to specific pollen. Results: During this period tree pollens were represented with 58% ± 21% of all measured air pollen species, while Betula pollen represented 15% ± 8% of all tree pollens. Betula pollination peaked in April. Allergen immunotherapy to Betula verrucosa in Serbia is entirely conducted as sublingual immunotherapy and represents 47.1% ± 1.4% of issued tree pollen SLIT. The use of pollen SLIT increased by 68% from 2015 to 2018, with an even greater increase in usage recorded for Betula SLIT-80%. Conclusions: This analysis shows a clear causative relationship between pollination and the type/prevalence of applied allergen immunotherapy. Information about the flowering seasons of allergenic plants is very important for people who suffer from allergy, for clinical allergologists, as well as for governing authorities. The presented data is of practical importance to the proper timing of immunotherapy initiation and of importance for urban landscaping. The obtained data can be the starting point for the instatement of a thorough epidemiological study and the inclusion of Serbia on the pollen map of Europe.


Assuntos
Ar/análise , Betula , Hipersensibilidade/terapia , Pólen/imunologia , Imunoterapia Sublingual/métodos , Árvores , Alnus , Betulaceae , Corylus , Exposição Ambiental , Humanos , Sérvia
9.
PLoS Pathog ; 16(2): e1008362, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-32097448

RESUMO

The transmissibility and pandemic potential of influenza viruses depends on their ability to efficiently replicate and be released from an infected host, retain viability as they pass through the environment, and then initiate infection in the next host. There is a significant gap in knowledge about viral properties that enable survival of influenza viruses between hosts, due to a lack of experimental methods to reliably isolate viable virus from the air. Using a novel technique, we isolate and characterise infectious virus from droplets emitted by 2009 pandemic H1N1-infected ferrets. We demonstrate that infectious virus is predominantly released early after infection. A virus containing a mutation destabilising the haemagglutinin (HA) surface protein displayed reduced survival in air. Infectious virus recovered from droplets exhaled by ferrets inoculated with this virus contained mutations that conferred restabilisation of HA, indicating the importance of influenza HA stability for between-host survival. Using this unique approach can improve knowledge about the determinants and mechanisms of influenza transmissibility and ultimately could be applied to studies of airborne virus exhaled from infected people.


Assuntos
Glicoproteínas de Hemaglutininação de Vírus da Influenza/metabolismo , Vírus da Influenza A Subtipo H1N1/metabolismo , Ar/análise , Microbiologia do Ar , Animais , Linhagem Celular , Transmissão de Doença Infecciosa , Furões/virologia , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Hemaglutininas/imunologia , Hemaglutininas/metabolismo , Humanos , Vírus da Influenza A Subtipo H1N1/patogenicidade , Influenza Humana/virologia , Viabilidade Microbiana/imunologia , Infecções por Orthomyxoviridae/virologia
10.
Biomed Res Int ; 2020: 8278943, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32076617

RESUMO

This research demonstrates the current use of air purification methods in the operating rooms (ORs) in China. 154 hospitals from 6 provinces were included in this survey to reflect the air purification methods of ORs in 2017. Air cleaning technology (ACT) is used in 124 (80.52%) hospitals. We find that the rates of using grade I, III, or IV clean operating room (COR) in tertiary hospitals are all higher than in lower level hospitals; the rate of using ACT in the ORs is higher, too. In addition, general hospitals have higher rate in using ACT in the ORs than specialized hospitals. The highest rate of using ACT in the ORs is in the eastern region of China. The number of hospitals using ACT, ultraviolet light disinfection, and air sterilizers (such as circulating air UV sterilizer) increased yearly. All grades of CORs can be maintained as required by more than 90% hospitals except grade II COR. In this research, we found air purification methods, especially the ACT, are widely used in hospitals' ORs. However, finding the way to select and use different air purification methods correctly is an urgent problem to be solved next.


Assuntos
Ar/análise , Desinfecção/métodos , Hospitais , Salas Cirúrgicas , Ar Condicionado , Microbiologia do Ar , Bactérias/isolamento & purificação , China , Transmissão de Doença Infecciosa/prevenção & controle , Desinfecção/instrumentação , Humanos , Raios Ultravioleta
11.
J Chromatogr A ; 1616: 460825, 2020 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-31924328

RESUMO

Several calibration approaches were evaluated for the quantitation of volatile organic compounds in air using miniaturized exhaustive and non-exhaustive sampling techniques, such as in-tube extraction (ITEX) and solid phase microextraction (SPME) Arrow. Eleven compounds, 2-ethyl-hexanol, hexanal, nonanal, toluene, ethyl-benzene, methyl isobutyl ketone, acetophenone, p-cymene, α-pinene, trimethylamine and triethylamine, all them found in the natural air samples, were selected as model analytes. Liquid injection, liquid standard addition to the sorbent bed and gas phase standards provided by an automatic permeation system, were evaluated in the case of ITEX packed with laboratory-made 10% polyacrylonitrile (PAN) material. Two different approaches, based on sampling of gas phase compounds from the permeation system and from sample vial containing gas phase standards, were evaluated for SPME Arrow with two different coatings, commercial divinylbenzene-poly(dimethylsiloxane) (DVB-PDMS) and laboratory-made mesoporous Mobil Composition of Matter No. 41 (MCM-41). In addition, interface model approach was used for the calculation of the real concentration of the target analytes in the sample from the total amount of analytes injected into the GC-MS in the case of SPME Arrow. Similar results were obtained with the different approaches used for the quantitation by ITEX and SPME Arrow. However, the use of gas phase standards with sample matrix similar to the natural samples, allowed the permeation system to provide the most reliable results for the quantitation of the target analytes. For this approach, linearity (expressed as r2 values) ranged between 0.991 and 0.999. The limit of detection ranged from 0.5 µg/m3 (trimethylamine, MCM-41) to 2.2 × 10-4 µg/m3 (methyl isobutyl ketone, MCM-41). In addition, the use of the fully automated permeation system provided good reproducibility values that were between 1.4% (acetophenone, MCM-41) and 7.8% (methyl isobutyl ketone, 10% PAN). The linear ranges were at least 3 order of magnitude for all the studied analytes with the exception of the calibration curve developed for trimethylamine with SPME Arrow (linear ranges between LOQ and 4.9 µg/m3 (DVB-PDMS) and LOQ and 9.8 µg/m3 (MCM-41)).


Assuntos
Ar/análise , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/análise , Calibragem , Cinética , Reprodutibilidade dos Testes
12.
PLoS One ; 15(1): e0227980, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31978133

RESUMO

INTRODUCTION: Particles in exhaled air (PEx) provide samples of respiratory tract lining fluid from small airways containing, for example, Surfactant protein A (SP-A) and albumin, potential biomarkers of small airway disease. We hypothesized that there are differences between morning, noon, and afternoon measurements and that the variability of repeated measurements is larger between days than within days. METHODS: PEx was obtained in sixteen healthy non-smoking adults on 11 occasions, within one day and between days. SP-A and albumin were quantified by ELISA. The coefficient of repeatability (CR), intraclass correlation coefficient (ICC), and coefficient of variation (CV) were used to assess the variation of repeated measurements. RESULTS: SP-A and albumin increased significantly from morning towards the noon and afternoon by 13% and 25% on average, respectively, whereas PEx number concentration and particle mean mass did not differ significantly between the morning, noon and afternoon. Between-day CRs were not larger than within-day CRs. CONCLUSIONS: Time of the day influences the contents of SP-A and albumin in exhaled particles. The variation of repeated measurements was rather high but was not influenced by the time intervals between measurements.


Assuntos
Albuminas/isolamento & purificação , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Proteína A Associada a Surfactante Pulmonar/isolamento & purificação , Sistema Respiratório/química , Adulto , Idoso , Ar/análise , Albuminas/metabolismo , Biomarcadores/química , Testes Respiratórios , Expiração/fisiologia , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Doença Pulmonar Obstrutiva Crônica/metabolismo , Doença Pulmonar Obstrutiva Crônica/patologia , Proteína A Associada a Surfactante Pulmonar/metabolismo , Sistema Respiratório/metabolismo , Espirometria/métodos
13.
Anesth Analg ; 130(4): 958-966, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31124837

RESUMO

BACKGROUND: The anesthetic side effects of propofol still occur in clinical practice because no reliable monitoring techniques are available. In this regard, continuous monitoring of propofol in breath is a promising method, yet it remains infeasible because there is large variation in the blood/exhaled gas partial pressure ratio (RBE) in humans. Further evaluations of the influences of breathing-related factors on RBE would mitigate this variation. METHODS: Correlations were analyzed between breathing-related factors (tidal volume [TV], breath frequency [BF], and minute ventilation [VM]) and RBE in 46 patients. Furthermore, a subset of 10 patients underwent pulmonary function tests (PFTs), and the parameters of the PFTs were then compared with the RBE. We employed a 1-phase exponential decay model to characterize the influence of VM on RBE. We also proposed a modified RBE (RBEM) that was not affected by the different breathing patterns of the patients. The blood concentration of propofol was predicted from breath monitoring using RBEM and RBE. RESULTS: We found a significant negative correlation (R = -0.572; P < .001) between VM and RBE (N = 46). No significant correlation was shown between PFTs and RBE in the subset (N = 10). RBEM demonstrated a standard Gaussian distribution (mean, 1.000; standard deviation [SD], 0.308). Moreover, the predicted propofol concentrations based on breath monitoring matched well with the measured blood concentrations. The 90% prediction band was limited to within ±1 µg·mL. CONCLUSIONS: The prediction of propofol concentration in blood was more accurate using RBEM than when using RBE and could provide reference information for anesthesiologists. Moreover, the present study provided a general approach for assessing the influence of relevant physiological factors and will inform noninvasive and accurate breath assessment of volatile drugs or metabolites in blood.


Assuntos
Anestésicos Intravenosos/análise , Anestésicos Intravenosos/sangue , Testes Respiratórios/métodos , Propofol/análise , Propofol/sangue , Adulto , Idoso , Ar/análise , Algoritmos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Testes de Função Respiratória , Taxa Respiratória , Volume de Ventilação Pulmonar
14.
Environ Pollut ; 256: 112050, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31481270

RESUMO

A dissolved air flotation (DAF) system is one of the water treatment processes that purifies contaminants through a buoyancy effect by attaching the moiety of micro-bubbles on their free surface. Since the DAF system was first used in the drinking water treatment in the 1960s, it has been recognized as an effective treatment for the water purification process. Most previous works laid great emphasis on the internal flow behaviors of fluid to improve the purification efficiency of the DAF system. Nevertheless, the practical implementation with a pilot plant indeed revealed some technical incompleteness for the DAF system. To circumvent for the technical incompleteness, numerical simulation based on computational fluid dynamics (CFD) has been carried out to understand the in-depth knowledge on internal flow phenomena in the DAF system. However, the standard k-ε turbulence model has been conventionally used in the most studies without any proper consideration process. Accordingly, the objectives of this study were to investigate the major effects on the internal flow behaviors for an efficient numerical simulation of DAF when a different turbulence model and micro-bubble parameters are used. As a result, the present study found that the standard k-ε model would be not proper for the internal flow simulation of the DAF process and a careful consideration would be required for a more accurate prediction. In addition, the present study examined a desirable internal flow pattern with various operating conditions of the micro-bubble. Consequently, the main findings of this study are expected to provide realistic information to related researchers for designing the DAF system with the optimal operating parameters.


Assuntos
Ar/análise , Hidrodinâmica , Microbolhas , Modelos Teóricos , Águas Residuárias/química , Purificação da Água/métodos , Simulação por Computador
16.
Rapid Commun Mass Spectrom ; 34(8): e8669, 2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-31758611

RESUMO

RATIONALE: Carbon-13 (13 C)-labelled plant material forms the basis for experiments elucidating soil organic carbon dynamics and greenhouse gas emissions. Quantitative field-scale tracing is only possible if plants are labelled homogeneously in large quantities. By using a laser spectrometer to automatically steer the isotopic ratio in the chamber, it is possible to obtain large amounts of homogeneously labelled plant material. METHODS: Ninety-six maize plants were labelled for 25 days until tassel formation in a 15 m3 walk-in growth chamber with a continuous air δ13 C-CO2 value of 400‰. A Los Gatos Research laser absorption spectrometer controlled the ambient δ13 C-CO2 value in the chamber through steering of the mass flow controllers with 13 C-enriched and natural abundance CO2 gas. RESULTS: Laser absorption spectroscopy steering kept the δ13 C value of chamber air between 368 and 426‰. The resulting 1 kg dry matter of 13 C-labelled shoots showed an average δ13 C value of 384‰ and accuracy of 8‰ (half width of the 95% confidence interval). Only the oldest leaves showed larger heterogeneity. The growth chamber eliminated variability between plants. The δ13 C value of the stabile material did not differ significantly from that of bulk material. CONCLUSIONS: Laser spectroscopy controlled 13 C labelling of plants in a walk-in growth chamber successfully kept the isotopic ratio of the CO2 in the chamber air constant. Therefore, large quantities of material were labelled homogeneously at the inter- and intra-plant level, thus establishing a method to provide high-quality input for quantitative isotopic tracer studies.


Assuntos
Isótopos de Carbono/análise , Marcação por Isótopo , Zea mays/química , Ar/análise , Dióxido de Carbono/análise , Marcação por Isótopo/métodos , Lasers , Espectrometria de Massas/métodos , Brotos de Planta/química , Brotos de Planta/crescimento & desenvolvimento , Zea mays/crescimento & desenvolvimento
17.
J UOEH ; 41(4): 425-430, 2019.
Artigo em Japonês | MEDLINE | ID: mdl-31866660

RESUMO

Dust indicators based on light scattering photometers are widely used to measure aerosol concentrations in work environments. These concentrations at workplaces in Japan are measured by these dust indicators and calibrated by mass concentration in order to control workers' exposure to dust. The mass concentration in a specific point in a workplace is measured simultaneously with a dust indicator. The mass concentration of the respirable fraction of dust particles should be determined by the gravimetric method with low volume air samplers or other devices, but some dust indicators are not equipped with a size separator for respirable fraction, and we used to get unstable results at the calibration. In this study, we designed miniature cyclones for a dust indicator and evaluated their performances of respirable fraction and PM2.5 fraction.


Assuntos
Ar/análise , Poeira/análise , Exposição Ambiental/análise , Saúde do Trabalhador , Local de Trabalho
18.
PLoS One ; 14(11): e0225047, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31697778

RESUMO

High amounts of aerial pollutants like dust and microorganisms can pose serious health hazards to animals and humans. The aim of the current study therefore was, to assess the efficiency of UVC irradiation combined to air filtration in reducing airborne microorganisms at laboratory scale. In a second part, a UVC-combined recirculating air filtration module (UVC module) was implemented in a small animal facility in order to assess its improvement of air quality with regard to airborne bacteria and dust. Tests at laboratory scale were performed using aerosols of Staphylococcus (S.) aureus, Actinobacillus pleuropneumoniae, porcine parvovirus (PPV) and porcine reproductive and respiratory syndrome virus. We varied relative humidity (RH) to evaluate its effect on UVC irradiation efficiency. In addition, viability of pathogens inside the filter material was determined over up to six months. UVC-combined air filtration resulted in a more than 99% reduction of viral and bacterial particles. RH had no influence on UVC efficiency. Viability in the filter matter varied depending on the pathogen used and RH with S. aureus and PPV being most resistant. In our small pig facility consisting of two separated barns, weekly air measurements were conducted over a period of 13 weeks (10 piglets) and 16 weeks (11 piglets), respectively. Airborne bacterial numbers were significantly lower in the barn equipped with the UVC module compared to the reference barn. On average a reduction to 37% of reference values could be achieved for bacteria, whereas the amount of total dust was reduced to a much lesser extent (i.e. to 78% of reference values). Measures taken in front of and behind the UVC module revealed a reduction of 99.4% for airborne bacteria and 95.0% for total dust. To conclude, recirculating air filtration combined to UVC provided efficient reduction of pathogens at laboratory and experimental scale. The implementation of such devices might improve the overall environmental quality in animal facilities.


Assuntos
Microbiologia do Ar , Ar/análise , Poeira/análise , Filtração , Abrigo para Animais , Raios Ultravioleta , Poluição do Ar , Amônia/análise , Animais , Dióxido de Carbono/análise , Umidade , Viabilidade Microbiana , Suínos , Temperatura
19.
Respir Res ; 20(1): 214, 2019 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-31558154

RESUMO

INTRODUCTION: At present, there are few methods available for monitoring respiratory diseases affecting distal airways. Bronchoscopy is the golden standard for sampling the lower airways. The recently developed method for collecting non-volatile material from exhaled air - PExA (Particles in Exhaled air) is a promising new tool, but no direct comparison between the two methods has yet been performed. The aim of the present study was to compare sampling using PExA with bronchial wash (BW) representing the larger more proximal airways and broncho-alveolar lavage (BAL) representing the distal airways. METHODS: 15 healthy non-smoking subjects (7 female/8 male), age 28 ± 4 years, with normal lung function were included in the study. PExA-sampling (2 × 250 ng particles) and bronchoscopy with BW (2 × 20 ml) and BAL (3 × 60 ml sterile saline) was performed. Albumin and Surfactant Protein A (SP-A) were analyzed with ELISA, and analyses of correlation were performed. RESULTS: A significant association was found between BAL-fluid albumin and PExA-albumin (rs:0.65 p = 0.01). There was also an association between SP-A in PExA and BAL, when corrected for albumin concentration (rs:0.61, p = 0.015). When correlating concentrations of albumin and SP-A in bronchial wash and PExA respectively, no associations were found. CONCLUSIONS: This is the first direct comparison between the bronchoscopy-based BW/BAL-fluids and material collected using the PExA methodology. Both albumin and albumin-corrected SP-A concentrations were significantly associated between BAL and PExA, however, no such association was found in either marker between BW and PExA. These results indicate that the PExA method samples the distal airways. PExA is thus considered a new promising non-invasive assessment for monitoring of the distal airways.


Assuntos
Lavagem Broncoalveolar/métodos , Monitorização Fisiológica/métodos , Proteína A Associada a Surfactante Pulmonar/análise , Adulto , Ar/análise , Albuminas/análise , Biomarcadores , Líquido da Lavagem Broncoalveolar/química , Broncoscopia , Expiração , Feminino , Voluntários Saudáveis , Humanos , Masculino , Adulto Jovem
20.
Ecotoxicol Environ Saf ; 185: 109708, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31563748

RESUMO

In this study, the effluent from the Bayer process of transforming bauxite into alumina, followed by dissolved air flotation (DAF) treatment, was evaluated to identify the best experimental conditions that generate less toxic or nontoxic effluent for discharge. Two freshwater organisms, the Chlorophyceae microalga Raphidocelis subcapitata (96-h algal growth inhibition test), and the microcrustacean Daphnia similis (48-h acute immobility test), were used to analyze the efficiency of effluent treatment by detecting and comparing the toxicity of the treated effluent. Experimental factorial planning used different concentrations of the coagulant ferric chloride and the flocculant Nalco® N-99-005B, and different recycle ratios. The highest recycle ratio (30%) and highest flocculant concentration (150 mg/L) had the best solids removal efficiency, above 90%. Probably the higher concentration of flocculant led to the formation of a more stable froth, promoting an increase in the hydrophobic characteristics of the flocs. Two operating conditions were satisfactory according to acute and chronic bioassays, with removal efficiencies of total suspended solids and turbidity higher than 98%, for both variables. Producers, R. subcapitata microalga, were more sensitive than the primary consumers, D. similis microcrustaceans, indicating the importance of performing tests with different bioindicators.


Assuntos
Ar/análise , Óxido de Alumínio/toxicidade , Material Particulado/toxicidade , Poluentes Químicos da Água/toxicidade , Purificação da Água/métodos , Óxido de Alumínio/análise , Animais , Daphnia/efeitos dos fármacos , Ecotoxicologia , Floculação , Microalgas/efeitos dos fármacos , Modelos Teóricos , Tamanho da Partícula , Material Particulado/análise , Poluentes Químicos da Água/análise
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