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1.
Huan Jing Ke Xue ; 43(4): 1814-1820, 2022 Apr 08.
Artigo em Chinês | MEDLINE | ID: mdl-35393805

RESUMO

To understand the levels of indoor air pollution and protect public health, our research group conducted monitoring of the concentrations of indoor pollutants (formaldehyde, benzene, toluene, xylene, total volatile organic compounds (TVOC), n-butyl acetate, ethylbenzene, styrene, and undecane) and a health effect assessment for 830 households of Xi'an City from December 2017 to December 2020. Simultaneously, the superposed effect of pollutants was analyzed. The results showed that the exceedance rates of formaldehyde, benzene, toluene, TVOC, and xylene were 92.1%, 39.7%, 11.7%, 8.9%, and 1.2% respectively, among which formaldehyde was the most serious pollutant. There was no significant difference in pollutant concentration and exceedance among different room types. The concentration of pollutants was the highest in summer due to the influence of temperature, humidity, and other factors. The results of the human health risk assessment showed that there were carcinogenic risks of formaldehyde and benzene for different age groups (children, adolescents, adults, and the elderly); children and the elderly were more at risk, whereas xylene, ethylbenzene, and toluene were at low risk (HI<1). The superposed effect of pollutants showed that superposition between indoor pollutants did exist, resulting in the obvious increase in pollutant toxicity. This study provides data reference and scientific basis for the characteristics and healthy effects of indoor residential pollutants in Xi'an City.


Assuntos
Poluentes Atmosféricos , Poluição do Ar em Ambientes Fechados , Compostos Orgânicos Voláteis , Adolescente , Adulto , Idoso , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Benzeno/análise , Criança , Monitoramento Ambiental/métodos , Formaldeído/análise , Humanos , Tolueno/análise , Compostos Orgânicos Voláteis/análise , Xilenos
2.
Int J Mol Sci ; 23(7)2022 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-35409403

RESUMO

Odorant-binding proteins (OBPs) are a group of small and soluble proteins present in both vertebrates and insects. They have a high level of structural stability and bind to a large spectrum of odorant molecules. In the environmental field, benzene is the most dangerous compound among the class of pollutants named BTEX (benzene, toluene, ethylbenzene, and xylene). It has several effects on human health and, consequently, it appears to be important to monitor its presence in the environment. Commonly, its detection requires the use of very sophisticated and time-consuming analytical techniques (GC-MS, etc.) as well as the presence of specialized personnel. Here, we present the application of an odorant-binding protein (pOBP) isolated from pigs as a molecular recognition element (MRE) for a low-energy impedenziometric biosensor for outdoor and real-time benzene detection. The obtained results show that the biosensor can detect the presence of 64 pM (5 µg/m3) benzene, the limit value of exposure for human health set by the European Directive 2008/50/EC.


Assuntos
Benzeno , Receptores Odorantes , Animais , Derivados de Benzeno , Suínos , Tolueno , Xilenos
3.
Pan Afr Med J ; 41: 92, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35465375

RESUMO

Introduction: Surgical Site Infections (SSIs) constitute 15%-45% of hospital acquired infections in sub-Saharan Africa. Cesarean section (CS) increases the risk of developing sepsis by 5-20 times and is highest when the operation is emergency. Therefore, the purpose of this study was to measure the effect of chloroxylenol in reducing the incidence of post cesarean SSIs at Mbarara Regional Referral Hospital (MRRH). Methods: a randomized controlled trial was conducted at MRRH maternity ward and mothers were randomized into either control or intervention arms. The intervention was a complete body bath with chloroxylenol antiseptic soap before the operation, while the control arm participants received a standard ward pre-operative preparation procedures. All participants were followed up for 30 days and assessed using an SSI screening tool. Results: ninety-six women were randomized, and 48 were assigned to each arm. The overall incidence of SSI was 30.21%. The incidence of SSI was significantly lower in the intervention compared to the control arm (6.25% in the intervention arm versus 54.17% in the control arm) (p-value <0.001). Chloroxylenol bath was protective of SSI with a 90% risk reduction for SSI (95% confidence interval of 67%-97%). Conclusion: a preoperative bath with chloroxylenol for pregnant mothers is associated with a significantly lower risk of post cesarean section surgical site infections. Health facilities with a high burden of post SSI should consider adding this simple and effective intervention to the existing infection prevention measures. Clinical Trials.gov registration (NCT03544710).


Assuntos
Anti-Infecciosos Locais , Cesárea , Feminino , Hospitais , Humanos , Incidência , Gravidez , Encaminhamento e Consulta , Sabões , Infecção da Ferida Cirúrgica/tratamento farmacológico , Infecção da Ferida Cirúrgica/epidemiologia , Infecção da Ferida Cirúrgica/prevenção & controle , Uganda , Xilenos
4.
J Am Chem Soc ; 144(17): 7861-7870, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35442020

RESUMO

Identifying zeolite catalysts that can simultaneously optimize p-xylene selectivity and feed utilization is critical to toluene alkylation with methanol (TAM). Here, we show that zeolite MCM-22 (MWW) has an exceptional catalyst lifetime in the TAM reaction at high operating pressure, conversion, and selectivity. We systematically probe the catalytic behavior of active sites in distinct topological features of MCM-22, revealing that high p-xylene yield and catalyst stability are predominantly attributed to sinusoidal channels and supercages, respectively. Using a combination of catalyst design and testing, density functional theory, and molecular dynamics simulations, we propose a spatiotemporal coke coupling phenomenon to explain a multistage p-xylene selectivity profile wherein the formation of light coke in supercages initiates the deactivation of unselective external surface sites. Our findings indicate that the specific nature of coke is critical to catalyst performance. Moreover, they provide unprecedented insight into the synchronous roles of distinct topological features giving rise to the exceptional stability and selectivity of MCM-22 in the TAM reaction.


Assuntos
Coque , Zeolitas , Catálise , Metanol , Tolueno/química , Xilenos , Zeolitas/química
5.
J Am Soc Mass Spectrom ; 33(5): 840-850, 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35471025

RESUMO

Gas-phase ion-mobility spectrometry provides a unique platform to study the effect of mobile charge(s) or charge location on collisional cross section and ion separation. Here, we evaluate the effects of cation/anion adduction in a series of xylene and pyridyl macrocycles that contain ureas and thioureas. We explore how zinc binding led to unexpected deprotonation of the thiourea macrocyclic host in positive polarity ionization and subsequently how charge isomerism due to cation (zinc metal) and anion (chloride counterion) adduction or proton competition among acceptors can affect the measured collisional cross sections in helium and nitrogen buffer gases. Our approach uses synthetic chemistry to design macrocycle targets and a combination of ion-mobility spectrometry mass spectrometry experiments and quantum mechanics calculations to characterize their structural properties. We demonstrate that charge isomerism significantly improves ion-mobility resolution and allows for determination of the metal binding mechanism in metal-inclusion macrocyclic complexes. Additionally, charge isomers can be populated in molecules where individual protons are shared between acceptors. In these cases, interactions via drift gas collisions magnify the conformational differences. Finally, for the macrocyclic systems we report here, charge isomers are observed in both helium and nitrogen drift gases with similar resolution. The separation factor does not simply increase with increasing drift gas polarizability. Our study sheds light on important properties of charge isomerism and offers strategies to take advantage of this phenomenon in analytical separations.


Assuntos
Hélio , Xilenos , Ânions , Isomerismo , Metais/química , Nitrogênio/química , Prótons , Zinco
6.
Bioresour Technol ; 353: 127131, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35398535

RESUMO

Catalytic fast pyrolysis of low sulfonated Kraft lignin was performed under different atmospheric environments such as N2, CH4, and the gas derived from CH4 decomposition (CH4-D). The use of Zn- or Mo-loaded HZSM-5 as catalyst led to a higher pyrolytic oil yield compared to parent HZSM-5 in CH4 and CH4-D atmospheres. The yields of benzene, toluene, and xylenes were increased by the synergistic effects from metal loading, higher H/Ceff ratio, higher acidity, and CH4 activation. The enhanced CH4 activation via metal loading resulted in higher methylation of alkyl moieties and 33% increase in the total yield of benzene, toluene, and xylenes in comparison to parent HZSM-5. A higher H/Ceff ratio of 6 via CH4 decomposition led to the formation of a hydro-pyrolysis environment. Moreover, the CH4-D environment showed H2/CH4 ratio of 0.36 in the product gas which warranted the presence of more H2 under the CH4-D pyrolysis environment.


Assuntos
Metano , Pirólise , Benzeno , Catálise , Meios de Cultura , Temperatura Alta , Lignina , Metais , Tolueno , Xilenos
7.
Toxicol Ind Health ; 38(5): 299-307, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35466827

RESUMO

Printing workers (PWs) are exposed to a mixture of solvents, yet the health risks associated with such exposuer are unknown. This study aimed to compare the serum levels of selected biomarkers of oxidative stress among occupationally exposed PWs to low-level of toluene and xylenes and unexposed controls. Associations between levels of such biomarkers and occupational exposures to toluene and xylene were also investigated. Urinary levels of hippuric acid (HA) and methyl hippuric acids (MHAs) as exposure biomarkers of toluene and xylenes, respectively, and serum levels of oxidative stress biomarkers, including total antioxidant capacity (TAC), malondialdehyde (MDA), and the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), were measured among the 84 subjects, comprising 44 PWs and 40 unexposed subjects. Mean concentrations of urinary HA and MHAs of PWs showed a significant increase compared with the unexposed controls. Although levels of urinary biomarkers of exposure to toluene (HA) and xylenes (MHAs) were well below the biological exposure indices (BEIs; ACGHI), PWs presented significantly increased serum levels of MDA, and significantly decreased serum activities of SOD and GPx compared to the unexposed controls. However, for serum TAC and CAT activity, no significant difference was observed between the two groups. Correlation analyses indicated that urinary levels of HA and MHAs were positively correlated with MDA levels and negatively correlated with GPx and SOD. Our study suggested that the alterations evidenced in serum levels of MDA, SOD, and GPx could be involved in the oxidative stress caused by co-exposure to low levels of toluene and xylene. Further investigation is needed to clarify the effect of low-level occupational exposure to solvents among PWs.


Assuntos
Exposição Ocupacional , Xilenos , Antioxidantes/análise , Biomarcadores , Humanos , Exposição Ocupacional/efeitos adversos , Exposição Ocupacional/análise , Estresse Oxidativo , Impressão Tridimensional , Soro/química , Solventes/análise , Superóxido Dismutase , Tolueno/toxicidade , Xilenos/análise
8.
Appl Environ Microbiol ; 88(8): e0011022, 2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35380460

RESUMO

2,6-Dimethylphenol (2,6-DMP) is a widely used chemical intermediate whose residue has been frequently detected in the environment, posing a threat to some aquatic organisms. Microbial degradation is an effective method to eliminate 2,6-DMP in nature. However, the genetic and biochemical mechanisms of 2,6-DMP metabolism remain unknown. Mycobacterium neoaurum B5-4 is a 2,6-DMP-degrading bacterium isolated in our previous study. Here, a 2,6-DMP degradation-deficient mutant of strain B5-4 was screened. Comparative genomic, transcriptomic, gene disruption, and genetic complementation data indicated that mpdA and mpdB are responsible for the initial step of 2,6-DMP degradation in M. neoaurum B5-4. MpdAB was predicted to be a two-component flavin-dependent monooxygenase system, which shows 32% and 36% identities with HsaAB from Mycobacterium tuberculosis CDC1551. The transcription of mpdA and mpdB was substantially increased upon exposure to 2,6-DMP. Nuclear magnetic resonance analysis showed that purified 6×His-MpdA and 6×His-MpdB hydroxylated 2,6-DMP and 2,3,6-trimethylphenol (2,3,6-TMP) at the para-position using NADH and flavin adenine dinucleotide (FAD) as cofactors. The apparent Km values of MpdAB for 2,6-DMP and 2,3,6-TMP were 0.12 ± 0.01 and 0.17 ± 0.01 mM, respectively, and the corresponding kcat/Km values were 4.02 and 2.84 s-1 mM-1, respectively. Since para-hydroxylated 2,3,6-TMP is a major precursor for vitamin E synthesis, the potential of MpdAB in vitamin E synthesis was preliminarily evaluated using whole-cell catalysis. Low expression levels of MpdA and 2,3,6-TMP cytotoxicity limited the efficiency of whole-cell catalysis. Together, this study reveals the genetic and biochemical basis for the initial step of 2,6-DMP biodegradation and provides candidate enzymes for vitamin E synthesis. IMPORTANCE Although the microbial degradation of the six isomers of dimethylphenol has been extensively studied, the genetic and biochemical mechanisms of 2,6-DMP degradation remain unclear. This study identified the genes responsible for the initial step in the 2,6-DMP catabolic pathway in M. neoaurum B5-4. Moreover, MpdAB also catalyzed the transformation of 2,3,6-TMP to 2,3,5-trimethylhydroquinone (2,3,5-TMHQ), a crucial step in vitamin E synthesis. Overall, this study provides candidate enzymes for both the bioremediation of 2,6-DMP contamination and the development of a green method to synthesize vitamin E.


Assuntos
Oxigenases de Função Mista , Xilenos , Biodegradação Ambiental , Flavinas , Oxigenases de Função Mista/genética , Oxigenases de Função Mista/metabolismo
9.
Anal Chem ; 94(10): 4286-4293, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35245018

RESUMO

Benzene, toluene, and xylene (BTX) are serious air pollutants emitted by the chemical industry. Real-time monitoring of these air pollutants would be a valuable tool to regulate emissions of these compounds and reduce the harm they cause to human health. Here, we demonstrate the first detection of BTX using incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS). The instrument was operated in the deep-ultraviolet spectral region between 252 and 286 nm, where aromatic compounds have intense π → π* absorption bands. The mirror reflectivity was calibrated by two methods and exceeded 99.63% at 266 nm. At an integration time of 60 s, the 1σ measurement sensitivities were estimated to be 7.2 ppbv for benzene, 21.9 ppbv for toluene, 10.2 ppbv for m-xylene, and 4.8 ppbv for p-xylene, respectively. The absorption cross sections of BTX were measured in this work with an uncertainty of 10.0% at a resolution of 0.74 nm. The absorption cross sections reported in this work were in good agreement with those from earlier studies after accounting for differences in spectral resolution. To demonstrate the ability of the instrument to quantify complex mixtures, the concentrations of m-xylene and p-xylene have been retrieved under five different mixing ratios. Instrumental improvements and measurements strategies for use in different applications are discussed.


Assuntos
Poluentes Atmosféricos , Poluentes Ambientais , Poluentes Atmosféricos/análise , Benzeno , Humanos , Análise Espectral , Tolueno/análise , Xilenos
10.
J Clin Lab Anal ; 36(4): e24321, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35235704

RESUMO

BACKGROUND: Loci controlling DNA double-strand breaks (DSBs) repair play an important role in defending against the harmful health effects of benzene, toluene, ethylbenzene, and xylene (BTEX), but their gene variants may alter their repair capacity. The aim of the current study was to determine the relationship of functional polymorphisms ATM-rs228589 A>T, WRN-rs1800392 G>T and H2AX-rs7759 A>G in DBS repair loci with the abnormal hematological indices in workers who exposed to BTEXs. METHODS: We included 141 cases with one or more abnormal hematological parameters, who had been occupationally exposed to BTEX chemicals and 152 controls with a similar exposure condition but without any abnormal hematological parameters. Atmospheric concentrations of BTEXs were measured and whole blood samples were taken from the participants to determine hematologic parameters and SNP genotyping. RESULTS: Results showed that T allele of ATM-rs228589 and G allele of H2AX-rs7759 had a higher frequency in cases than controls (p = 0.012 and p = 0.001, respectively). Also, AT and TT genotypes of ATM-rs228589 and AG and GG genotypes of H2AX-rs7759 were higher in cases compared to controls. The AT and TT genotypes of ATM-rs228589 have significant associations with a risk of hematological abnormalities in the codominant (AT vs. AA, p = 0.018), dominant (AT + TT vs. AA, p = 0.010) and overdominant (AT vs. AA + TT, p = 0.037) models. The GG and AG genotypes of H2AX-rs7759 were in relation with increased risk of abnormal hematological indices under codominant (GA vs. AA, p = 0.009 & GG vs. AA, p = 0.005), dominant (AG + GG vs. AA, p = 0.001), and recessive (GG vs. AA + AG, p = 0.025) models. CONCLUSIONS: These observations may help to understand the mechanisms of BTEX hematotoxicity and identify useful biomarkers of risk assessment for workers exposed to BTEX.


Assuntos
Benzeno , Xilenos , Proteínas Mutadas de Ataxia Telangiectasia/genética , Benzeno/efeitos adversos , Derivados de Benzeno , Predisposição Genética para Doença/genética , Histonas , Humanos , Polimorfismo de Nucleotídeo Único/genética , Tolueno
11.
Artigo em Inglês | MEDLINE | ID: mdl-35329092

RESUMO

Subsurface VOC monitoring has been mainly based on manual sampling, transport, and analysis, which would require a sufficient amount of samples to ensure data accuracy and reliability, and additional costs to ensure sample quality. Therefore, a continuous on-site monitoring system is desirable for accurate measurement and subsequent risk assessment. In this study, benzene, toluene, ethylbenzene, and xylene (BTEX) were continuously monitored by the system based on a thermal desorber (TD) and gas chromatography (GC) in an oil-contaminated site that consisted of saturated and unsaturated zones. For the saturated zone, fully automated groundwater sampling and purging processes were performed, and the gasified samples were applied to the TD-GC system. For the unsaturated zone, the gaseous sample in the site was directly applied to the TD-GC system. After verifying the accuracy and precision of the monitoring system, the continuous monitoring system was successfully operated for more than a month in the field. The monitoring system used in this study is applicable to other sites for continuous monitoring, thus providing a scientific background for advanced risk assessment and policy development.


Assuntos
Derivados de Benzeno , Xilenos , Benzeno/análise , Derivados de Benzeno/análise , Cromatografia Gasosa , Monitoramento Ambiental/métodos , Reprodutibilidade dos Testes , Tolueno/análise , Xilenos/análise
12.
Enzyme Microb Technol ; 157: 110020, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35240538

RESUMO

Benzene, toluene, and xylene (BTX) are volatile aromatic compounds used in industries, however, they are hazardous when released into the environment. BTX degradation by Aspergillus niger cells combined with semiconducting zinc sulfide (ZnS) nanoparticles was explored in batch systems. Experiments were conducted individually for benzene, toluene, and xylene as well as in binary and trinary mixtures using A. niger cells-ZnS nanobiohybrids. The mechanism governing the removal of BTX by both A. niger cells and A. niger cells-ZnS nanobiohybrids were elucidated. Complete BTX degradation was achieved in 75 min and 60 min, respectively, by nanobiohybrids composed of chemical and biological ZnS nanoparticles in the presence of UV-A light at 1.83 * 1018 photons/second and 1.68 * 1018 photons/second, respectively. The removal efficiency was in the order of the molecular weight for A. niger cells, whereas for the light-driven A. niger-ZnS nanobiohybrids, the removal efficiency was according to the methyl group number. Further, the respiratory coefficient and volumetric mass transfer coefficient (Ka) values are higher for A. niger cells compared to the light-driven A. niger-ZnS nanobiohybrids.


Assuntos
Tolueno , Xilenos , Aspergillus niger/metabolismo , Benzeno/química , Sulfetos , Tolueno/química , Tolueno/metabolismo , Xilenos/química , Compostos de Zinco
13.
Sci Total Environ ; 827: 154186, 2022 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-35231512

RESUMO

Energy shortage and environmental pollution have attracted long-term attention. In this study, CaO were prepared from waste eggshell (EGC), preserved egg shell (PEC), clam shell (CLC) and crab shell (CRC), which were then compared with commercial CaO (CMC) to catalyze microwave-assisted pyrolysis of waste cooking oil (WCO) for enrichment of aromatics in bio-oil. The characterization results indicated that EGC and CLC contained 95.54% and 95.61% CaO respectively, which were higher than that of CMC (95.11%), and the pore properties of EGC were the best. In addition, the effects of CaO type and catalytic mode on pyrolysis were studied. In CaO catalytic pyrolysis, CMC and CLC in-situ catalysis produced more aromatics than ex-situ catalysis, and PEC and CRC were more conducive to aromatics formation in ex-situ condition. EGC was conducive to produce benzene, toluene and xylene (BTX) both in in-situ (19.04%) and ex-situ (20.76%) catalytic pyrolysis. In CaO/HZSM-5 catalysis, the optimal dual catalytic mode for generating monocyclic aromatic hydrocarbons (MAHs) was Mode A (CaO separated from HZSM-5 for ex-situ catalysis), and EGC/HZSM-5 performed well in benzene, toluene and xylene (BTX) production.


Assuntos
Micro-Ondas , Pirólise , Animais , Benzeno , Biocombustíveis , Biomassa , Catálise , Culinária , Temperatura Alta , Óleos Vegetais , Polifenóis , Tolueno , Xilenos
14.
Environ Int ; 163: 107194, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35339921

RESUMO

To meet the needs of the rapid development of education, there have been growing investments in the issue of university infrastructures. However, few studies have paid attention to the assessment and monetization of health risks in newly renovated teaching buildings. In this study, concentrations of the benzene series (BTEX) group were measured in five areas of three newly renovated teaching buildings. A total of 135 BTEX samples were collected using passive diffusion monitors and analyzed by GC-FID. Human health risk assessments were conducted by using probabilistic methods for four types of population exposure to BTEX. The results showed that the cancer risk of benzene accounted for most of the total in each group. There was over 90% probability of excess cancer risks in the areas within the tested buildings; and the non-cancer risks were all within the acceptable level. The health risks of men were greater than those of women, and those of teachers were higher than those of students. The model calculation results of Disability-Adjusted Life Year (DALY) and Willingness to Pay (WTP) indicated that the average price that society was willing to pay to offset the health damage caused in these newly renovated teaching buildings was 381.35 yuan/year. For the first time, this study highlights the health risks of newly built teaching buildings in universities, points out the urgent need to improve the control of BTEX sources in this type of indoor environment; moreover, it provides theoretical support for the society and occupational protection departments to compensate for the health damage to professionals.


Assuntos
Poluentes Atmosféricos , Benzeno , Poluentes Atmosféricos/análise , Benzeno/análise , Derivados de Benzeno/análise , Monitoramento Ambiental/métodos , Feminino , Humanos , Masculino , Medição de Risco , Tolueno/análise , Xilenos
15.
Rocz Panstw Zakl Hig ; 73(1): 121-130, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35322964

RESUMO

Background: The Thai government has been developing its Eastern Economic Corridor (EEC), which spans three provinces, with the aim of improving connections with other Asian nations. Since this strategic development, the number of trucks, private car, and passenger car registrations have continued to grow, with a corresponding increase in related to benzene, toluene, ethylbenzene, and xylene (BTEX). Objectives: This study aims to compare the levels of trans, trans-muconic acid (t, t MA); toluene (TU); mandelic acid (MA); and methyl hippuric acid (MHA) in the urine of gas station employees, considering demographic and occupational factors. Material and methods: These employees worked either near or away from the fuel dispenser, and there 100 people in each group. Data were collected using interviews and testing environmental air and urine samples for benzene, toluene, ethyl benzene, and xylene (BTEX). Results: The results showed that BTEX concentrations were just detectable in all 200 cases (100%). The mean (±SD) urine level of t, t MA was 449.28 (±213.32) µg/g creatinine, while the median (min-max) was 428.23 (95.58-1202.56) µg/g creatinine. The mean TU was 0.011 (0.001) mg/L, while the median (min-max) was 0.011 (0.010-0.013) mg/L. MA levels were higher inside the pollution control zone than they were outside the zone (p=.009). Employees who practiced poor personal hygiene had relatively high urinary toluene and MHA levels (p=.009) and those who did not wear personal protective equipment (PPE) had relatively high MA levels (p=.040). Conclusion: The results of this study revealed statistically significant biomarkers influencing the levels of t, t MA; TU; MA; and MHA in urine. The recommendations of this study are that employers should provide their employees with suitable PPE, check regularly to ensure that it is worn, and strongly encourage employees to take care of their sanitation. Employees should take appropriate breaks and days off to minimize their exposure to BTEX.


Assuntos
Exposição Ocupacional , Humanos , Rim/química , Estações do Ano , Tailândia , Xilenos/urina
16.
Sensors (Basel) ; 22(3)2022 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-35162023

RESUMO

Electrocorticography (ECoG) is a conventional, invasive technique for recording brain signals from the cortical surface using an array of electrodes. In this study, we developed a highly flexible 22-channel ECoG microelectrode array on a thin Parylene film using novel fabrication techniques. Narrow (<40 µm) and thin (<500 nm) microelectrode patterns were first printed on PDMS, then the patterns were transferred onto Parylene films via vapor deposition and peeling. A custom-designed, 3D-printed connector was built and assembled with the Parylene-based flexible ECoG microelectrode array without soldering. The impedance of the assembled ECoG electrode array was measured in vitro by electrochemical impedance spectroscopy, and the result was consistent. In addition, we conducted in vivo studies by implanting the flexible ECoG sensor in a rat and successfully recording brain signals.


Assuntos
Eletrocorticografia , Xilenos , Animais , Microeletrodos , Polímeros , Ratos
17.
Molecules ; 27(3)2022 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-35164389

RESUMO

As one of the major sources of volatile pollutants in indoor air, gaseous emissions from adhesives during interior decoration have attracted increasing concern. Identifying major volatile pollutants and the risk in adhesive gaseous emissions is of great significance, but remains rarely reported. In the present research, we assessed the major volatile pollutants emitted from white emulsion adhesive and silicone adhesive samples (n = 30) from three aspects: chemical composition, odor and health risk contributions. The results showed that a total of 21 volatile pollutants were detected. Significantly, xylene was the most concentrated compound from white emulsion adhesives, accounting for 45.51% of the total concentrations. Butanone oxime was the most concentrated compound in silicone adhesives, accounting for 69.86% of the total concentrations. The trends in odor concentration (evaluated by the odor activity value method) over time were well correlated with the total chemical concentrations. Xylene (58.00%) and butanone oxime (76.75%) showed the highest odor contribution, respectively. Moreover, from an integrated perspective of chemical emissions, odor and health risk contributions, xylene, ethylbenzene, ethyl acetate and benzene were identified as the key volatile pollutants emitted from the white emulsion adhesives, while butanone oxime, butanone, and ethanol were the key volatile pollutants emitted from the silicone adhesives. This study not only identified the key volatile pollutants but also provided characteristics of odor and health risks of gas emitted from adhesives.


Assuntos
Adesivos/química , Poluentes Atmosféricos/análise , Odorantes/análise , Compostos Orgânicos Voláteis/análise , Butanonas/análise , Monitoramento Ambiental , Humanos , Xilenos/análise
18.
Environ Res ; 209: 112810, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35101395

RESUMO

BACKGROUND: Benzene, Toluene, Ethylbenzene, and Xylenes (BTEXs) are a group of aromatic air pollutants from fossil fuels. There is no research on associations of the BTEXs mixture with telomere length (TL), a marker of cellular aging, in the general population. METHODS: We analyzed a subsample of 549 US adults aged 20-59 years from the National Health and Nutrition Examination Survey 1999-2000. BTEXs samples were collected by passive exposure badges worn by participants for 48-72 h. Levels of BTEXs were measured with gas chromatography/mass spectrometry. Leukocyte TL was measured with qPCR. We used Bayesian Kernel Machine Regression (BKMR) to examine the effect of the BTEXs mixture on TL adjusting for potential confounders. Analyses were stratified by tobacco smoking status (serum cotinine≥10 ng/mL vs. <10 ng/mL). RESULTS: Levels of personal exposure to BTEXs were detectable in most participants and were relatively higher in the 150 smokers than in the 399 nonsmokers. The BTEXs were moderately or strongly intercorrelated (0.5 < r ≤ 0.9, P < 0.05). All chemicals had weak, inverse correlations with TL (-0.1 0.05). In BKMR models among the nonsmokers, the BTEXs mixture was significantly inversely associated with TL at a low range of the BTEXs (20th-65th percentile) but was not associated with TL at a higher range (>65th percentile). Also, we found a U-shape association of benzene and a positive association of ethylbenzene with TL independent of other BTEXs. Among smokers, neither the BTEXs mixture nor any individual BTEXs were significantly associated with TL. CONCLUSION: Within a low-to-middle range, exposure to the BTEXs mixture may be associated with shorter telomere length in the general nonsmoking population.


Assuntos
Benzeno , Xilenos , Adulto , Teorema de Bayes , Benzeno/análise , Benzeno/toxicidade , Derivados de Benzeno/toxicidade , Estudos Transversais , Humanos , Pessoa de Meia-Idade , Inquéritos Nutricionais , Telômero , Tolueno/análise , Xilenos/análise , Xilenos/toxicidade , Adulto Jovem
19.
Artigo em Inglês | MEDLINE | ID: mdl-35138241

RESUMO

Two Gram-reaction-negative strains, designated as B13T and MA2-2, were isolated from two different aromatic hydrocarbon-degrading enrichment cultures and characterized using a polyphasic approach to determine their taxonomic position. The two strains had identical 16S rRNA gene sequences and were most closely related to Pinisolibacter ravus E9T (97.36 %) and Siculibacillus lacustris SA-279T (96.33 %). Cells were facultatively aerobic rods and motile with a single polar flagellum. The strains were able to degrade ethylbenzene as sole source of carbon and energy. The assembled genome of strain B13T had a total length of 4.91 Mb and the DNA G+C content was 68.8 mol%. The predominant fatty acids (>5 % of the total) of strains B13T and MA2-2 were C18 : 1 ω7c/C18 : 1 ω6c, C16 : 1 ω7c/C16 : 1 ω6c and C16 : 0. The major ubiquinone of strain B13T was Q10, while the major polar lipids were phosphatidyl-N-methylethanolamine, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and a phospholipid. Based on phenotypic characteristics and phylogenetic data, it is concluded that strains B13T and MA2-2 are members of the genus Pinisolibacter and represent a novel species for which the name Pinisolibacter aquiterrae sp. nov. is proposed. The type strain of the species is strain B13T (=LMG 32346T=NCAIM B.02665T).


Assuntos
Alphaproteobacteria/classificação , Benzeno , Filogenia , Xilenos , Alphaproteobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Benzeno/metabolismo , DNA Bacteriano/genética , Ácidos Graxos/química , Hidrocarbonetos Aromáticos/metabolismo , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Xilenos/metabolismo
20.
BMC Anesthesiol ; 22(1): 44, 2022 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-35144541

RESUMO

BACKGROUND: Perioperative hypothermia is a common occurrence, particularly with the elderly and pediatric age groups. Hypothermia is associated with an increased risk of perioperative complications. One method of preventing hypothermia is warming the infused fluids given during surgery. The enFlow™ intravenous fluid warmer has recently been reintroduced with a parylene coating on its heating blocks. In this paper, we evaluated the impact of the parylene coating on the new enFlow's fluid warming capacity. METHODS: Six coated and six uncoated enFlow cartridges were used. A solution of 10% propylene glycol and 90% distilled H2O was infused into each heating cartridge at flow rates of 2, 10, 50, 150, and 200 ml/min. The infused fluid temperature was set at 4 °C, 20 °C, and 37 °C. Output temperature was recorded at each level. Data for analysis was derived from 18 runs at each flow rate (six cartridges at three temperatures). RESULTS: The parylene coated fluid warming cartridge delivered very stable output of 40 °C temperatures at flow rates of 2, 10, and 50 ml/min regardless of the temperature of the infusate. At higher flow rates, the cartridges were not able to achieve the target temperature with the colder fluid. Both cartridges performed with similar efficacy across all flow rates at all temperatures. CONCLUSIONS: At low flow rates, the parylene coated enFlow cartridges was comparable to the original uncoated cartridges. At higher flow rates, the coated and uncoated cartridges were not able to achieve the target temperature. The parylene coating on the aluminum heating blocks of the new enFlow intravenous fluid warmer does not negatively affect its performance compared to the uncoated model.


Assuntos
Administração Intravenosa/métodos , Calefação/instrumentação , Calefação/métodos , Polímeros , Xilenos , Desenho de Equipamento , Humanos , Infusões Intravenosas
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