104 research outputs found
Nivo policikličnih aromatičnih ugljovodonika u gasnoj i čestičnoj fazi u školama na različitim lokacijama u Srbiji
This study investigated seasonal variation of PAHs and their partition between gas and particulate-bounded phases in indoor and outdoor air in 4 schools In Serbia located at different locations. The sampling campaigns were conducted during one workweek at each school successively. Campaigns were conducted in schools during heating and non-heating seasons in December 2011 and June 2012. Seasonal variations of gas and particle-bounded PAHs concentrations were observed with higher levels during heating season. The highest total PAH values were associated with the gas phase in both sampling periods. The total PAHs concentration at indoor and at the outdoor sites, during heating season, ranged from 88.45 to 447.72 ng/m(3) and 201.69 to 1017.15 ng/m(3), respectively. During non-heating season, the total PAHs concentration ranged from 36.91 to 271.57 ng/m(3) in Indoor environment and 27.00 to 132.32 ng/m(3) in outdoor environment. Most of the I/O ratios were less than 1, which indicated that the indoor PAHs were mostly from outdoor sources. The use of diagnostic ratio showed that traffic emission and coal combustion are the major sources of PAHs. Only the diagnostic ratios for the school located near the industrial area showed significant deviation compared to other schools.U ovom radu su istraživane sezonske promene PAH i njihova raspodela, u gasnoj fazi i respirabilnim česticama u vazduhu unutrašnjeg prostora i spoljašnje sredine u 4 škole u Srbiji koje se nalaze na različitim lokacijama. Kampanja uzorkovanja je sprovedena tokom jedne radne nedelje u toku grejnog i negrejnog perioda (od decembra 2011. do juna 2012.) u svakoj školi. Uočene su sezonske promene nivoa PAH u gasnoj fazi i česticama, sa višim koncentracijama tokom grejnog perioda. Izmerena je veća vrednost zbira ukupnih PAH tokom oba perioda u gasnoj fazi nego PAH u česticama. Ukupna koncentracija PAH tokom grejnog perioda u unutrašnjem prostoru se kretala u opsegu od 88,45 do 447,72 ng/m3, a u spoljašnjoj sredini od 201,69 do 1017,15 ng/m3. Tokom negrejnog perioda, ukupna koncentracija PAH-ova je bila 36,91-271,57 ng/m3 u unutrašnjem prostoru, dok je u spoljašnjoj sredini bila 27,00-132,32 ng/m3. Većina I/O odnosa je bila manja od 1, što ukazuje da PAH u unutrašnjem prostoru uglavnom potiču iz spoljašnjeg vazduha. Na osnovu dijagnostičkih odnosa zaključeno je da su saobraćaj i sagorevanje uglja glavni izvori PAH. Jedino dijagnostički odnosi za školu koja se nalazi u blizini industrijske zone pokazuju značajno odstupanje u poređenju sa drugim školama
Koncentracija suspendovanih čestica (PM10 I PM2.5) i njihov odnos unutra/spolja u odabranim obrazovnim ustanovama u Nišu
Mass concentrations of particulate matter (PM) fractions were measured in educational buildings in the city of Nis, Serbia. Two sampling campaigns were conducted in winter periods. The first campaign was in the period from 21 February to 15 April 2010 at the Faculty of Occupational Safety (FOS) and the second campaign was from 20 March to 4 April 2013 at the primary school Void Karadorde (VK). PM measurements were carried out with low volume samplers Sven/Leckel LVS3. The average daily PM10 concentration inside the FOS (47.0 +/- 21.8 mu g/m(3)) was lower than PM10 concentration in outdoor air (50.7 +/- 28.1 mu g/m(3)). The average daily PM10 concentration inside the VK (54.6 +/- 17.6 mu g/m(3)) was higher than in outdoor air (47.9 +/- 22.8 mu g/m(3)). The 24-hours, average PM10 concentrations at FOS exceeded the EU limit value (50 mu g/m(3)) during 34% of days outdoors and 39% of days indoors. The 24-hours average PM10 concentrations at VK exceeded the limit value during 35% of days outdoors and 53% of days indoors. The 24-hours average PM2.5 concentrations at VK exceeded the WHO daily mean guideline value (25 mu g/m(3)) during 71% of days outdoors and 88% of days indoors. The average PM10 I/O ratio at VK was 1.57 during teaching hours, and 1.00 during no teaching hours. Similarly, average PM2.5 I/O ratio at VK was 1.11 during teaching hours and 0.90 during no teaching hours. Average daily PM2.5/PM10 ratio in the ambient air at VK was 0.87 and 0.82 at FOS. Very strong correlations between the indoor and outdoor PM concentrations were observed at VK during no teaching hours (r gt 0.8). Moderate to strong negative correlations were found between the wind speed and PM at both schools. High outdoor PM concentrations and resuspension of particles are possible reasons for the elevated indoor PM concentrations found in the study.U radu su prikazani rezultati merenja suspendovanih čestica frakcija PM10 i PM2.5 u dve izabrane obrazovne ustanove u Nišu. Kampanje merenja sprovedene su u zimskom periodu. Prva u periodu od 21.02. do 15.04.2010. na Fakultetu zaštite na radu (FOS), a druga u periodu od 20.03. do 04.04.2013. u osnovnoj školi Vožd Karađorđe (VK). Uzorkovanje suspendovanih čestica vršeno je uzorkivačima Sven/Leckel LVS3, simultano, unutar i izvan odabranih ustanova. Prosečna dnevna koncentracija čestica PM10 unutar objekta FOS (47,0±21,8 μg/m3) bila je niža u odnosu na prosečnu dnevnu koncentraciju PM10 u ambijentalnom vazduhu (50,7±28,1 μg/m3). Prosečna dnevna koncentracija čestica PM10 unutar objekta VK (54.6±17.6 μg/m3) bila je viša u odnosu na prosečnu dnevnu koncentraciju PM10 u ambijentalnom vazduhu (47.9±22.8 μg/m3). Srednje dnevne koncentracije čestica PM10 izmerene na lokaciji FOS u ambijentalnom vazduhu prelazile su dnevnu graničnu vrednost (50 ìg/m3) tokom 34% dana trajanja kampanje merenja. Srednje dnevne koncentracije čestica PM10 izmerene unutar objekta FOS prelazile su dnevnu graničnu vrednost tokom 39% dana trajanja kampanje merenja. Srednje dnevne koncentracije čestica PM10 izmerene na lokaciji VK u ambijentalnom vazduhu prelazile su dnevnu graničnu vrednost tokom 35% dana trajanja kampanje merenja, odnosno tokom 53% dana trajanja kampanje u unutrašnjosti objekta VK. Srednje dnevne koncentracije čestica PM2,5 izmerene na lokaciji VK u ambijentalnom vazduhu prelazile su dnevnu graničnu vrednost (25 ìg/m3) tokom 71% dana trajanja kampanje, odnosno tokom 88% dana u unutrašnjosti objekta VK. Prosečan dnevni odnos unutra/spolja čestica frakcije PM10 na lokaciji VK iznosio je 1,57 u vreme nastave, odnosno 1,00 kada nije bilo nastave. Prosečan dnevni odnos unutra/spolja čestica frakcije PM2,5 na lokaciji VK iznosio je 1.11 u vreme nastave, odnosno 0.90 kada nije bilo nastave. Prosečan dnevni odnos PM2,5/PM10 u ambijentalnom vazduhu na lokaciji VK bio je 0,87, odnosno 0,82 na lokaciji FOS. Detektovana je veoma jaka korelacija između koncentracija suspendovanih čestica unutar i izvan objekta VK u periodu kada nije bilo nastave (r gt 0.8). Umerena do jaka korelacija detektovana je između brzine vetra i koncentracija suspendovanih čestica na obe lokacije (FOS i VK). Visoke koncentracije suspendovanih čestica u ambijentalnom vazduhu i resuspenzija čestica najverovatniji su razlog koji utiče na povećane koncentracije suspendovanih čestica u unutrašnjem prostoru posmatranih obrazovnih ustanova
The Basic Aspects of Wind Turbine Foundations in Our Conditions
Following the global trends and accordingly to the energy conditions, wind turbines are being succesfully built in Serbia, which leads to an increase in the fund of knowledge in this field. In the paper, on the basis of general geotechnical conditions in Serbia, the most common types of wind turbine foundations will be presented. Problems of the load analysis of these structures will be presented in brief, and also the conceptual requirements in their design. Connection between the
tower and the foundation will be briefly described as well. Despite the global aspiration to eneralize and industrialize this aspect of the construction of wind turbines, in specific cases remains a number of issues, regarding component materials, the application of standards and design codes, which are usually not adjusted to the design of wind turbine foundations
Swelling, Mechanical and Antimicrobial Studies of Ag/P(HEMA/IA)/PVP Semi-IPN Hybrid Hydrogels
A simple and fast approach to the design and production of new hybrid polymeric biomaterials with silver particles is presented in this work. Silver/semi-interpenetrating network hybrid hydrogels (Ag/semi-IPNHHs) were prepared through an optimized solution crosslinking copolymerization of 2-hydroxyethyl methacrylate (HEMA) and itaconic acid (IA), in the presence of PVP, a silver salt and a reducing green agent (Ag/P(HEMA/IA)/PVP). PVP was chosen due to its protective, reduction, and nucleation properties in the production of metal particles. The structure of the Ag/semi-IPNHH was characterized by Fourier transform infrared spectroscopy (FTIR). The presence of silver and PVP in the network was confirmed by FTIR spectra. The results obtained by dynamic mechanical analysis (DMA) showed good mechanical properties for all samples. The swelling studies of Ag/P(HEMA/IA)/PVP were conducted in the temperature range of 25-55 degrees C, in the buffer of pH 7.40. The Ag/semi-IPNHH showed temperature-sensitive swelling properties, with the lower critical solution temperature (LCST) values in the physiologically interesting interval. The antimicrobial activity of the samples was tested using E. coli, S. aureus and C. albicans pathogens. It was concluded that the antimicrobial potential depends on the hydrogels composition and the type of microbes12th Annual YUCOMAT Conference, Sep 06-10, 2010, Herceg Novi, Montenegr
Tumor-derived interleukin-10 as a prognostic factor in stage III patients undergoing adjuvant treatment with an autologous melanoma cell vaccine.
OBJECTIVES: Interleukin-10 (IL-10) downregulates T-cell-mediated immune responses. We studied the association between IL-10 production by freshly isolated melanoma cell suspensions in vitro and overall survival in patients undergoing adjuvant treatment with a vaccine prepared from the same autologous melanoma cells modified with a hapten, dinitrophenyl (DNP).
METHODS: Forty-four patients with cutaneous melanoma (29 stage III and 15 stage IV) were prospectively evaluated. Tumor cells were extracted from metastatic deposits for production of DNP-modified autologous melanoma cell vaccine. Small aliquots of the melanoma cell suspensions were separated prior to vaccine processing and cultured overnight for IL-10 production. Based on a blind assessment of the distribution of IL-10 levels in the culture supernatants, a cutoff of 200 pg/ml was used to define high versus low IL-10 producers. Cox regression model was used for multivariate analysis. Overall survival was calculated using the Kaplan-Meier method, and survival curves were compared with the log-rank test.
RESULTS: Out of 44 patients, 29 were low and 15 were high IL-10 producers. The median OS was significantly worse for high compared with low IL-10 producers (10.5 months vs. 42 months; P = 0.022). In stage III patients, the multivariate hazard ratio for high versus low IL-10 producers was 2.92 (95% CI, 1.04-8.20; P = 0.041). The corresponding hazard ratio in stage IV patients was 0.92 (95% CI, 1.04-8.20; P = 0.888).
CONCLUSIONS: High IL-10 production in the tumor microenvironment could be a determinant of clinical outcomes in stage III melanoma patients receiving autologous melanoma cell vaccine
A Herpesvirus Encoded Deubiquitinase Is a Novel Neuroinvasive Determinant
The neuroinvasive property of several alpha-herpesviruses underlies an uncommon infectious process that includes the establishment of life-long latent infections in sensory neurons of the peripheral nervous system. Several herpesvirus proteins are required for replication and dissemination within the nervous system, indicating that exploiting the nervous system as a niche for productive infection requires a specialized set of functions encoded by the virus. Whether initial entry into the nervous system from peripheral tissues also requires specialized viral functions is not known. Here we show that a conserved deubiquitinase domain embedded within a pseudorabies virus structural protein, pUL36, is essential for initial neural invasion, but is subsequently dispensable for transmission within and between neurons of the mammalian nervous system. These findings indicate that the deubiquitinase contributes to neurovirulence by participating in a previously unrecognized initial step in neuroinvasion
Cyclophosphamide Chemotherapy Sensitizes Tumor Cells to TRAIL-Dependent CD8 T Cell-Mediated Immune Attack Resulting in Suppression of Tumor Growth
Background: Anti-cancer chemotherapy can be simultaneously lymphodepleting and immunostimulatory. Pre-clinical models clearly demonstrate that chemotherapy can synergize with immunotherapy, raising the question how the immune system can be mobilized to generate anti-tumor immune responses in the context of chemotherapy. Methods and Findings: We used a mouse model of malignant mesothelioma, AB1-HA, to investigate T cell-dependent tumor resolution after chemotherapy. Established AB1-HA tumors were cured by a single dose of cyclophosphamide in a CD8 T cell- and NK cell-dependent manner. This treatment was associated with an IFN-α/β response and a profound negative impact on the anti-tumor and total CD8 T cell responses. Despite this negative effect, CD8 T cells were essential for curative responses. The important effector molecules used by the anti-tumor immune response included IFN-γ and TRAIL. The importance of TRAIL was supported by experiments in nude mice where the lack of functional T cells could be compensated by agonistic anti-TRAIL-receptor (DR5) antibodies. Conclusion: The data support a model in which chemotherapy sensitizes tumor cells for T cell-, and possibly NK cell-, mediated apoptosis. A key role of tumor cell sensitization to immune attack is supported by the role of TRAIL in tumor resolution and explains the paradox of successful CD8 T cell-dependent anti-tumor responses in the absence of CD8 T cell expansion
An evaluation tool kit of air quality micro-sensing units.
Recent developments in sensory and communication technologies have made the development of portable air-quality (AQ) micro-sensing units (MSUs) feasible. These MSUs allow AQ measurements in many new applications, such as ambulatory exposure analyses and citizen science. Typically, the performance of these devices is assessed using the mean error or correlation coefficients with respect to a laboratory equipment. However, these criteria do not represent how such sensors perform outside of laboratory conditions in large-scale field applications, and do not cover all aspects of possible differences in performance between the sensor-based and standardized equipment, or changes in performance over time. This paper presents a comprehensive Sensor Evaluation Toolbox (SET) for evaluating AQ MSUs by a range of criteria, to better assess their performance in varied applications and environments. Within the SET are included four new schemes for evaluating sensors' capability to: locate pollution sources; represent the pollution level on a coarse scale; capture the high temporal variability of the observed pollutant and their reliability. Each of the evaluation criteria allows for assessing sensors' performance in a different way, together constituting a holistic evaluation of the suitability and usability of the sensors in a wide range of applications. Application of the SET on measurements acquired by 25 MSUs deployed in eight cities across Europe showed that the suggested schemes facilitates a comprehensive cross platform analysis that can be used to determine and compare the sensors' performance. The SET was implemented in R and the code is available on the first author's website.CITI-SENSE, initiated in October 2012, is a four year Collaborative Project partly funded by the EU FP7-ENV-2012 under grant agreement 308524
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