Publications by authors named "Jakub Ondracek"

16 Publications

  • Page 1 of 1

Cultivation of with Feedback Regulation of Glucose Concentration Controlled by Optical Fiber Glucose Sensor.

Sensors (Basel) 2021 Jan 14;21(2). Epub 2021 Jan 14.

Faculty of Environment, Jan Evangelista Purkyně University in Ústí nad Labem, Pasteurova 3632/15, 40096 Ústí nad Labem, Czech Republic.

Glucose belongs among the most important substances in both physiology and industry. Current food and biotechnology praxis emphasizes its on-line continuous monitoring and regulation. These provoke increasing demand for systems, which enable fast detection and regulation of deviations from desired glucose concentration. We demonstrated control of glucose concentration by feedback regulation equipped with in situ optical fiber glucose sensor. The sensitive layer of the sensor comprises oxygen-dependent ruthenium complex and preimmobilized glucose oxidase both entrapped in organic-inorganic polymer ORMOCER. The sensor was placed in the laboratory bioreactor (volume 5 L) to demonstrate both regulations: the control of low levels of glucose concentrations (0.4 and 0.1 mM) and maintenance of the glucose concentration (between 2 and 3.5 mM) during stationary phase of cultivation of . Response times did not exceed 6 min (average 4 min) with average deviation of 4%. Due to these regulation characteristics together with durable and long-lasting (≥2 month) sensitive layer, this feedback regulation system might find applications in various biotechnological processes such as production of low glucose content beverages.
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http://dx.doi.org/10.3390/s21020565DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7830682PMC
January 2021

Three-Year Study of Markers of Oxidative Stress in Exhaled Breath Condensate in Workers Producing Nanocomposites, Extended by Plasma and Urine Analysis in Last Two Years.

Nanomaterials (Basel) 2020 Dec 6;10(12). Epub 2020 Dec 6.

J. Heyrovský Institute of Physical Chemistry CAS, Dolejškova 3, 182 23 Prague 8, Czech Republic.

Human data concerning exposure to nanoparticles are very limited, and biomarkers for monitoring exposure are urgently needed. In a follow-up of a 2016 study in a nanocomposites plant, in which only exhaled breath condensate (EBC) was examined, eight markers of oxidative stress were analyzed in three bodily fluids, i.e., EBC, plasma and urine, in both pre-shift and post-shift samples in 2017 and 2018. Aerosol exposures were monitored. Mass concentration in 2017 was 0.351 mg/m during machining, and 0.179 and 0.217 mg/m during machining and welding, respectively, in 2018. In number concentrations, nanoparticles formed 96%, 90% and 59%, respectively. In both years, pre-shift elevations of 50.0% in EBC, 37.5% in plasma and 6.25% in urine biomarkers were observed. Post-shift elevation reached 62.5% in EBC, 68.8% in plasma and 18.8% in urine samples. The same trend was observed in all biological fluids. Individual factors were responsible for the elevation of control subjects' afternoon vs. morning markers in 2018; all were significantly lower compared to those of workers. Malondialdehyde levels were always acutely shifted, and 8-hydroxy-2-deoxyguanosine levels best showed chronic exposure effect. EBC and plasma analysis appear to be the ideal fluids for bio-monitoring of oxidative stress arising from engineered nanomaterials. Potential late effects need to be targeted and prevented, as there is a similarity of EBC findings in patients with silicosis and asbestosis.
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http://dx.doi.org/10.3390/nano10122440DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7762143PMC
December 2020

Influence of sample surface topography on laser ablation process.

Talanta 2021 Jan 13;222:121512. Epub 2020 Aug 13.

Materials Characterization and Advanced Coatings, Central European Institute of Technology, Purkyňova 656/123, Brno, Czech Republic; Faculty of Mechanical Engineering, Brno University of Technology, Technická 2, Brno, Czech Republic.

In this work we discuss how sample surface topography can significantly influence the laser ablation (LA) process and, in turn, the analytical response of the LA Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) method. Six different surface topographies were prepared on a certified aluminium alloy sample BAM 311 and SRM NIST 610 to investigate the phenomenon. All the samples were repetitively measured by LA-ICP-MS using a spot by spot analysis. The effect of laser fluence in the range of 1-13 J/cm was studied. For majority of measured isotopes, the ICP-MS signal was amplified with roughening of the sample surface. A stronger effect was observed on the Al alloy sample, where the more than sixty-time enhancement was achieved in comparison to the polished surface of the sample. Since the effect of surface topography is different for each analyte, it can be stated that surface properties affect not only the ICP-MS response, but also elemental fractionation in LA. The presented results show that different surface topographies may lead to misleading data interpretation because even when applying ablation preshots, the signal of individual elements changes. The utmost care must be taken when preparing the surface for single shot analysis or chemical mapping. On the other hand, by roughening the sample surface, it is possible to significantly increase the sensitivity of the method for individual analytes and supress a matrix effect.
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http://dx.doi.org/10.1016/j.talanta.2020.121512DOI Listing
January 2021

The genotoxic effects in the leukocytes of workers handling nanocomposite materials.

Mutagenesis 2020 09;35(4):331-340

Department of Nanotoxicology and Molecular Epidemiology, Institute of Experimental Medicine of the Czech Academy of Sciences, Videnska, Prague, Czech Republic.

The extensive development of nanotechnologies and nanomaterials poses a number of questions to toxicologists about the potential health risks of exposure to nanoparticles (NP). In this study, we analysed DNA damage in the leukocytes of 20 workers who were long-term exposed (18 ± 10 years) to NP in their working environment. Blood samples were collected in September 2016, before and after a shift, to assess (i) the chronic effects of NP on DNA (pre-shift samples) and (ii) the acute effects of exposure during the shift (the difference between pre- and post-shift samples). The samples from matched controls were taken in parallel with workers before the shift. Leukocytes were isolated from heparinised blood on a Ficoll gradient. The enzyme-modified comet assay (DNA formamido-pyrimidine-glycosylase and endonuclease III) demonstrated a considerable increase of both single- and double-strand breaks in DNA (DNA-SB) and oxidised bases when compared with the controls (2.4× and 2×, respectively). Acute exposure induced a further increase of DNA-SB. The welding and smelting of nanocomposites represented a higher genotoxic risk than milling and grinding of nanocomposite surfaces. Obesity appeared to be a factor contributing to an increased risk of oxidative damage to DNA. The data also indicated a higher susceptibility of males vs. females to NP exposure. The study was repeated in September 2017. The results exhibited similar trend, but the levels of DNA damage in the exposed subjects were lower compared to previous year. This was probably associated with lower exposure to NP in consequence of changes in nanomaterial composition and working operations. The further study involving also monitoring of personal exposures to NP is necessary to identify (i) the main aerosol components responsible for genotoxic effects in workers handling nanocomposites and (ii) the primary cause of gender differences in response to NP action.
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http://dx.doi.org/10.1093/mutage/geaa016DOI Listing
September 2020

Spatial-temporal variability of aerosol sources based on chemical composition and particle number size distributions in an urban settlement influenced by metallurgical industry.

Environ Sci Pollut Res Int 2020 Nov 5;27(31):38631-38643. Epub 2020 Jul 5.

Department of Public Health Sciences, University of Rochester Medical Center, 265 Crittenden Boulevard, Rochester, NY, 14642-0708, USA.

The Moravian-Silesian region of the Czech Republic with its capital city Ostrava is a European air pollution hot spot for airborne particulate matter (PM). Therefore, the spatiotemporal variability assessment of source contributions to aerosol particles is essential for the successful abatement strategies implementation. Positive Matrix Factorization (PMF) was applied to highly-time resolved PM chemical composition (1 h resolution) and particle number size distribution (PNSD, 14 nm - 10 μm) data measured at the suburban (Ostrava-Plesná) and urban (Ostrava-Radvanice) residential receptor sites in parallel during an intensive winter campaign. Diel patterns, meteorological variables, inorganic and organic markers, and associations between the chemical composition factors and PNSD factors were used to identify the pollution sources and their origins (local, urban agglomeration and regional). The source apportionment analysis resolved six and four PM sources in Plesná and Radvanice, respectively. In Plesná, local residential combustion sources (coal and biomass combustion) followed by regional combustion sources (residential heating, metallurgical industry) were the main contributors to PM. In Radvanice, local residential combustion and the metallurgical industry were the most important PM sources. Aitken and accumulation mode particles emitted by local residential combustion sources along with common urban sources (residential heating, industry and traffic) were the main contributors to the particle number concentration (PNC) in Plesná. Additionally, accumulation mode particles from local residential combustion sources and regional pollution dominated the particle volume concentration (PVC). In Radvanice, local industrial sources were the major contributors to PNC and local coal combustion was the main contributor to PVC. The source apportionment results from the complementary datasets elucidated the relevance of highly time-resolved parallel measurements at both receptor sites given the specific meteorological conditions produced by the regional orography. These results are in agreement with our previous studies conducted at this site. Graphical abstract.
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http://dx.doi.org/10.1007/s11356-020-09694-0DOI Listing
November 2020

DNA Methylation Profiles in a Group of Workers Occupationally Exposed to Nanoparticles.

Int J Mol Sci 2020 Mar 31;21(7). Epub 2020 Mar 31.

Department of Machining and Assembly, Department of Engineering Technology, Department of Material Science, Faculty of Mechanical Engineering, Technical University in Liberec, Studentska 1402/2 Liberec, Czech Republic.

The risk of exposure to nanoparticles (NPs) has rapidly increased during the last decade due to the vast use of nanomaterials (NMs) in many areas of human life. Despite this fact, human biomonitoring studies focused on the effect of NP exposure on DNA alterations are still rare. Furthermore, there are virtually no epigenetic data available. In this study, we investigated global and gene-specific DNA methylation profiles in a group of 20 long-term (mean 14.5 years) exposed, nanocomposite, research workers and in 20 controls. Both groups were sampled twice/day (pre-shift and post-shift) in September 2018. We applied Infinium Methylation Assay, using the Infinium MethylationEPIC BeadChips with more than 850,000 CpG loci, for identification of the DNA methylation pattern in the studied groups. Aerosol exposure monitoring, including two nanosized fractions, was also performed as proof of acute NP exposure. The obtained array data showed significant differences in methylation between the exposed and control groups related to long-term exposure, specifically 341 CpG loci were hypomethylated and 364 hypermethylated. The most significant CpG differences were mainly detected in genes involved in lipid metabolism, the immune system, lung functions, signaling pathways, cancer development and xenobiotic detoxification. In contrast, short-term acute NP exposure was not accompanied by DNA methylation changes. In summary, long-term (years) exposure to NP is associated with DNA epigenetic alterations.
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http://dx.doi.org/10.3390/ijms21072420DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7177382PMC
March 2020

The repeated cytogenetic analysis of subjects occupationally exposed to nanoparticles: a pilot study.

Mutagenesis 2019 09;34(3):253-263

Department of Machining and Assembly, Technical University in Liberec, Liberec, Czech Republic.

The application of nanomaterials has been rapidly increasing during recent years. Inhalation exposure to nanoparticles (NP) may result in negative toxic effects but there is a critical lack of human studies, especially those related to possible DNA alterations. We analyzed pre-shift and post-shift a group of nanocomposite researchers with a long-term working background (17.8 ± 10.0 years) and matched controls. The study group consisted of 73.2% males and 26.8% females. Aerosol exposure monitoring during a working shift (involving welding, smelting, machining) to assess the differences in exposure to particulate matter (PM) including nanosized fractions <25-100 nm, and their chemical analysis, was carried out. A micronucleus assay using Human Pan Centromeric probes, was applied to distinguish between the frequency of centromere positive (CEN+) and centromere negative (CEN-) micronuclei (MN) in the binucleated cells. This approach allowed recognition of the types of chromosomal damage: losses and breaks. The monitoring data revealed differences in the exposure to NP related to individual working processes, and in the chemical composition of nanofraction. The cytogenetic results of this pilot study demonstrated a lack of effect of long-term (years) exposure to NP (total frequency of MN, P = 0.743), although this exposure may be responsible for DNA damage pattern changes (12% increase of chromosomal breaks-clastogenic effect). Moreover, short-term (daily shift) exposure could be a reason for the increase of chromosomal breaks in a subgroup of researchers involved in welding and smelting processes (clastogenic effect, P = 0.037). The gender and/or gender ratio of the study participants was also an important factor for the interpretation of the results. As this type of human study is unique, further research is needed to understand the effects of long-term and short-term exposure to NP.
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http://dx.doi.org/10.1093/mutage/gez016DOI Listing
September 2019

Leukocyte telomere length is not affected by long-term occupational exposure to nano metal oxides.

Ind Health 2019 Nov 28;57(6):741-744. Epub 2019 Mar 28.

Institute of Chemical Process Fundamentals CAS, Czech Republic.

The aim of this study was to ascertain whether long-term occupational exposure to nanoparticles would affect relative leukocyte telomere length (LrTL). We analysed occupational exposure to size-resolved aerosol particles, with special emphasis on nanoparticles at two workshops: i/ the production of nanocomposites containing metal oxides; ii/ laboratory to test experimental exposure of nano-CuO to rodents. Thirty five exposed researchers (age 39.5 ± 12.6 yr; exposure duration 6.0 ± 3.7 yr) and 43 controls (40.4 ± 10.5 yr) were examined. LrTL did not significantly (p=0.14) differ between the exposed researchers (0.92 ± 0.13) and controls (0.86 ± 0.15). In addition, no significant correlation (r=-0.22, p=0.22) was detected between the duration of occupational exposure and LrTL. The results remained non-significant after multiple adjustments for age, sex and smoking status. Our pilot results suggest that relative leukocyte telomere length is not affected by occupational exposure to nanoparticles.
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http://dx.doi.org/10.2486/indhealth.2018-0146DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6885603PMC
November 2019

The influence of local emissions and regional air pollution transport on a European air pollution hot spot.

Environ Sci Pollut Res Int 2019 Jan 17;26(2):1675-1692. Epub 2018 Nov 17.

Department of Aerosols Chemistry and Physics, Institute of Chemical Process Fundamentals of the Czech Academy of Sciences, v.v.i, Rozvojová 1/135, 165 02, Prague 6 - Suchdol, Czech Republic.

The EU air quality standards have been frequently exceeded in one of the European air pollution hot spots: Ostrava. The aim of this study was to perform an air quality comparison between an urban site (Radvanice), which has a nearby metallurgical complex, and a suburban site (Plesná) to estimate air pollution sources and determine their local and/or regional origins. Twenty-four hour PM and PM (particular matter) concentrations, detailed mass size distributions (MSDs) to distinguish the sources of the fine and coarse PM, and their chemical compositions were investigated in parallel at both sites during the winter of 2014. Positive matrix factorization (PMF) was applied to the PM and PM chemical compositions to investigate their sources. During the measurement campaign, prevailing northeastern-southwestern (NE-SW) wind directions (WDs) were recorded. Higher average PM concentration was measured in Radvanice than in Plesná, whereas PM concentrations were similar at both sites. A source apportionment analysis revealed six and five sources for PM and PM, respectively. In Radvanice, the amount of PM and the most chemical species were similar under SW and NE WD conditions. The dominant sources were industrial (43% for PM and 27% for PM), which were caused by a large metallurgical complex located to the SW, and biomass burning (25% for PM and 36% for PM). In Plesná, the concentrations of PM and all species significantly increased under NE WD conditions. Secondary inorganic aerosols were dominant, with the highest contributions deriving from the NE WD. Therefore, regional pollution transport from the industrial sector in Silesian Province (Poland) was evident. Biomass burning contributed 22% and 24% to PM and PM, respectively. The air quality in Ostrava was influenced by local sources and regional pollution transport. The issue of poor air quality in this region is complex. Therefore, international cooperation from both states (the Czech Republic and Poland) is needed to achieve a reduction in air pollution levels.
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http://dx.doi.org/10.1007/s11356-018-3670-yDOI Listing
January 2019

Deep Airway Inflammation and Respiratory Disorders in Nanocomposite Workers.

Nanomaterials (Basel) 2018 Sep 16;8(9). Epub 2018 Sep 16.

UMass, Lowell, Department of Biomedical and Nutritional Sciences, Zuckerberg College of Health Sciences, Lowell, MA 01854, USA.

Thousands of researchers and workers worldwide are employed in nanocomposites manufacturing, yet little is known about their respiratory health. Aerosol exposures were characterized using real time and integrated instruments. Aerosol mass concentration ranged from 0.120 mg/m³ to 1.840 mg/m³ during nanocomposite machining processes; median particle number concentration ranged from 4.8 × 10⁴ to 5.4 × 10⁵ particles/cm³. The proportion of nanoparticles varied by process from 40 to 95%. Twenty employees, working in nanocomposite materials research were examined pre-shift and post-shift using spirometry and fractional exhaled nitric oxide (FeNO) in parallel with 21 controls. Pro-inflammatory leukotrienes (LT) type B4, C4, D4, and E4; tumor necrosis factor (TNF); interleukins; and anti-inflammatory lipoxins (LXA4 and LXB4) were analyzed in their exhaled breath condensate (EBC). Chronic bronchitis was present in 20% of researchers, but not in controls. A significant decrease in forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) was found in researchers post-shift ( ˂ 0.05). Post-shift EBC samples were higher for TNF ( ˂ 0.001), LTB4 ( ˂ 0.001), and LTE4 ( ˂ 0.01) compared with controls. Nanocomposites production was associated with LTB4 ( ˂ 0.001), LTE4 ( ˂ 0.05), and TNF ( ˂ 0.001), in addition to pre-shift LTD4 and LXB4 (both ˂ 0.05). Spirometry documented minor, but significant, post-shift lung impairment. TNF and LTB4 were the most robust markers of biological effects. Proper ventilation and respiratory protection are required during nanocomposites processing.
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http://dx.doi.org/10.3390/nano8090731DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6164906PMC
September 2018

Markers of Oxidative Stress in the Exhaled Breath Condensate of Workers Handling Nanocomposites.

Nanomaterials (Basel) 2018 Aug 10;8(8). Epub 2018 Aug 10.

Department of Biomedical and Nutritional Sciences, Zuckerberg College of Health Sciences, Lowell, MA 01854, USA.

Researchers in nanocomposite processing may inhale a variety of chemical agents, including nanoparticles. This study investigated airway oxidative stress status in the exhaled breath condensate (EBC). Nineteen employees (42.4 ± 11.4 y/o), working in nanocomposites research for 18.0 ± 10.3 years were examined pre-shift and post-shift on a random workday, together with nineteen controls (45.5 ± 11.7 y/o). Panels of oxidative stress biomarkers derived from lipids, nucleic acids, and proteins were analyzed in the EBC. Aerosol exposures were monitored during three major nanoparticle generation operations: smelting and welding (workshop 1) and nanocomposite machining (workshop 2) using a suite of real-time and integrated instruments. Mass concentrations during these operations were 0.120, 1.840, and 0.804 mg/m³, respectively. Median particle number concentrations were 4.8 × 10⁴, 1.3 × 10⁵, and 5.4 × 10⁵ particles/cm³, respectively. Nanoparticles accounted for 95, 40, and 61%, respectively, with prevailing Fe and Mn. All markers of nucleic acid and protein oxidation, malondialdehyde, and aldehydes C₆⁻C were elevated, already in the pre-shift samples relative to controls in both workshops. Significant post-shift elevations were documented in lipid oxidation markers. Significant associations were found between working in nanocomposite synthesis and EBC biomarkers. More research is needed to understand the contribution of nanoparticles from nanocomposite processing in inducing oxidative stress, relative to other co-exposures generated during welding, smelting, and secondary oxidation processes, in these workshops.
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http://dx.doi.org/10.3390/nano8080611DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6116291PMC
August 2018

Evaluation of nanoparticle emissions from a laser printer in an experimental chamber and estimation of the human particle dose.

Environ Sci Pollut Res Int 2018 May 27;25(13):13103-13117. Epub 2018 Feb 27.

School of Environmental Engineering, Technical University of Crete (TUC), Polytechneioupolis, 73100, Chania, Greece.

The aim of this study was to evaluate the nanoparticle emissions from a laser printer in a chamber in conjunction with emissions from printers in a print room (PR) and to characterize the processes that lead to increased nanoparticle concentrations, as well as to estimate the human particle dose of the printers' users. Measurements were conducted in a small stainless steel environmental chamber under controlled conditions, where the evolution of particle size distributions (PSDs) with time and printed pages was studied in detail. Printer was generating nanoparticles (vast majority ˂ 50 nm with mode on ~ 15 nm) primarily during cold startup. Previously, 1-week sampling was also done in a PR at the Technical University of Crete, where the tested laser printer is installed along with three other printers. Similarly, as it was observed in the chamber study, printers' startup on any given day was characterized by a sharp increase in particle number (PN) concentrations. Average measured PN concentrations during printing hours in PR (5.4 × 10 #/cm) is similar to the one observed in chamber measurements (6.7 × 10 #/cm). The ExDoM2 dosimetry model was further applied to calculate the deposition of particles in the human respiratory tract. More precisely, the increase in particle dose for an adult Caucasian male was 14.6- and 24.1-fold at printers' startup, and 1.2- and 5.2-fold during printing in the PR and experimental chamber, respectively, compared to the exposure dose at background concentrations (BCs).
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http://dx.doi.org/10.1007/s11356-018-1448-xDOI Listing
May 2018

Manikin-based size-resolved penetrations of CE-marked filtering facepiece respirators.

J Occup Environ Hyg 2017 12;14(12):965-974

b Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic , Prague , Czech Republic.

The purpose of this manikin-based study was to determine the percentage penetrations of nine CE-marked filtering facepiece respirator models (two samples from each) from filtering classes FFP1, FFP2, and FFP3 and to demonstrate by an independent measurement method the disadvantages and shortcomings of the currently valid European Norm (EN 149:2001) for filtering facepieces. All of the filtering facepieces were evaluated size-selectively in an experimental chamber using charge-neutralized monodisperse ammonium sulfate in 9 sizes ranging from 20-400 nm of count median diameter (CMD) under flowrate of 95 L/min. The results were then compared to the previous study concerning penetrations of 47-mm diameter filters cut from the filtering material of identical filtering facepieces. Although these two experimental methods for measuring penetrations of filtering materials from filtering facepieces are in good agreement (R = 0.91), the results show within-respirator variations in all three filtering classes (5.5-19.3% for all FFRs in FFP1, 2.8-8.5% in FFP2, and 0.1-2.8% in FFP3). The most penetrating particle size (MPPS) in this study was found to be in the range of 25-65 nm (CMD), which is in agreement with the range of 30-60 nm found in the previous study. Moreover, 7 out of 9 FFR models reached higher penetrations from manikin-based respirator measurements than during measurements of filters from the respective respirators. Furthermore, penetration levels increased up to ∼50% when the respirator was not sealed around the face of the manikin, indicating that the real protection level provided by these filtering facepieces may be even lower if the respirator does not fit perfectly. Considering that poor filtration efficiency and poor fit may increase under real work conditions, the particle penetration is even higher than was found in this study. Therefore, the CE-marked respirators examined in this study may not be efficient in providing the expected level of protection for workers exposed to nanoparticles.
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http://dx.doi.org/10.1080/15459624.2017.1358816DOI Listing
December 2017

Single Usage of a Kitchen Degreaser Can Alter Indoor Aerosol Composition for Days.

Environ Sci Technol 2017 Jun 10;51(11):5907-5912. Epub 2017 May 10.

Institute of Chemical Process Fundamentals of the CAS , Prague CZ-165 02, Czech Republic.

To the best of our knowledge, this study represents the first observation of multiday persistence of an indoor aerosol transformation linked to a kitchen degreaser containing monoethanol amine (MEA). MEA remaining on the cleaned surfaces and on a wiping paper towel in a trash can was able to transform ammonium sulfate and ammonium nitrate into (MEA)SO and (MEA)NO. This influence persisted for at least 60 h despite a high average ventilation rate. The influence was observed using both offline (filters, impactors, and ion chromatography analysis) and online (compact time-of-flight aerosol mass spectrometer) techniques. Substitution of ammonia in ammonium salts was observed not only in aerosol but also in particles deposited on a filter before the release of MEA. The similar influence of other amines is expected based on literature data. This influence represents a new pathway for MEA exposure of people in an indoor environment. The stabilizing effect on indoor nitrate also causes higher indoor exposure to fine nitrates.
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http://dx.doi.org/10.1021/acs.est.6b06050DOI Listing
June 2017

Global MicroRNA Expression Profiling Identifies Unique MicroRNA Pattern of Radioresistant Glioblastoma Cells.

Anticancer Res 2017 03;37(3):1099-1104

Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic

Glioblastoma multiforme (GBM) is the most aggressive intracranial tumor characterized with infaust prognosis. Despite advances in neurosurgical and radiotherapeutic techniques and chemotherapy, the median overall survival ranges between 12-15 months from diagnosis. The main cause of treatment failure is considered the presence of tumor cells resistant to conventional therapy, mainly radiotherapy. MicroRNAs (miRNAs) are small, non-coding RNAs that function as post-transcriptional regulators of gene expression and have been repeatedly proven to play important roles in pathogenesis and biological features of many cancers, including GBM and its radioresistant phenotype. In our study, we established radioresistant cells from the commonly used human GBM cell lines T98G, U87MG and U251. Consequently, we performed global miRNA expression profiling in both radioresistant and parental cell lines and identified 113 miRNAs with significantly different expression (p<0.05) between these two groups (73 miRNAs were up-regulated, 40 miRNAs were down-regulated). Some of these miRNAs have been previously described in relation to ionizing radiation, and others were herein identified for the first time. We believe that after deeper functional investigation of identified miRNAs in relation to radioresistance, these miRNAs present potential predictive biomarkers or therapeutic targets in GBM.
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http://dx.doi.org/10.21873/anticanres.11422DOI Listing
March 2017

Physical properties and lung deposition of particles emitted from five major indoor sources.

Air Qual Atmos Health 2017 25;10(1):1-14. Epub 2016 Aug 25.

Division of Environmental Health & Risk Management, School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT UK ; Department of Environmental Sciences/Center of Excellence in Environmental Studies, King Abdulaziz University, PO Box 80203, Jeddah, 21589 Saudi Arabia.

The physical properties of indoor particles were measured with an Scanning Mobility Particle Sizer (SMPS) system (14.6-850 nm), an Aerodynamic Particle Sizer (APS, 0.54-18 μm) and an Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA) in an apartment located in an urban background site in Prague (Czech Republic) from 15 August to 8 September, 2014. The total particle maximum number concentration was 9.38 × 10, 1.46 × 10, 2.89 × 10, 2.25 × 10 and 1.57 × 10 particles cm for particles released from vacuum cleaning, soap/W5 cleaning spray, smoking, incense burning and cooking (frying) activities, respectively. Particles emitted from cleaning activities showed unimodal number size distributions, with the majority of particles (>98.2 %) in the ultrafine size range (Dp <100 nm) and modes at a diameter of 19.8 nm for vacuum cleaning and 30.6 nm for soap/W5 cleaning. Smoking and incense burning predominantly generated particles in the accumulation mode with a count median diameter around 90-150 nm while cooking emissions showed a bimodal structure with a main mode at 47.8 nm. Particles from vacuum cleaning, incense burning, smoking and cooking emissions were found to be "nearly hydrophobic" with an average growth factor (G) around 1.01-1.10, while particles emitted from desk cleaning using organic compounds were found to be "less-hygroscopic" (G ∼1.12-1.16). Based on an adjusted MPPD model with a consideration of the hygroscopic properties of particles, the total lung deposition fractions of these particles by number when they penetrate into the human lung were 0.73 ± 0.02, 0.62 ± 0.03, 0.37 ± 0.03, 0.32 ± 0.03 and 0.49 ± 0.02 for vacuum cleaning, desk cleaning, smoking, incense burning and cooking, respectively.
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http://dx.doi.org/10.1007/s11869-016-0424-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5216066PMC
August 2016