146 research outputs found

    Adsorption of Escherichia coli Using Bone Char

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    The aim of study was providing a novel adsorbent for the removal of Escherichia coli (E.coli) as a microbial model from contaminated air especially in hospital units using bone char (BC). The BC was prepared from cattle animal bone by pyrolysis in a furnace at 450°C for 2 h. The characteristics of BC have been determined using scanning electron microscopy (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), pHzpc, apparent density and iodine number. Nebulizer system applied to convert the E.coli with different concentration into bioaerosols. The variables included: BC weights (4-10 g), the adsorbent pore size (20-40 mesh) and microbial concentrations (103-107 CFU/mL). Characteristics of the adsorbent show the ability of the BC to remove E.coli fromair. The results shows the higher amounts of BC, the more efficiency achieved to purify contaminate air and particles in the range of 20-40 mesh were more practical in removing bioaerosols. An efficient time for removing the more E.coli was 30 minutes. The maximum bacterial efficiency removal achieved was 99.99%. Comparison of removalefficiency with other literature showed that the BC particles were better mineral sorbents than other organic adsorbents and a commercial activated carbon. In this study, we investigated a novel air purification adsorbent and the information obtained in the paper is of fundamental significance for the mineral adsorbents especially bone charin cleaning of indoor bioaeroso

    Escherichia Coli Removal from Water Using Electrophotocatalytic Method

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    Electrochemical has the suitable method of drinking water disinfection. This method leads to production of hydroxyl radicals which are known powerfull oxidant agent. In recent years, water disinfection using electrophotocatalytic method is spreading. The aim of this experimental applied study is to evaluate the removal of Escherichia Coli, as the microbial contamination indicator of water, from drinking water using electrophotocatalytic method. The contaminated water in an electrophotocatalytic reactor were prepared by adding 102-103 cell of E. coli bacteria to drinking water. The studied variables were pH (6-8), the number of bacterial suspensions (102-103 cells / ml), the UV-A lamps (2-4 W), times (5-40 min), the distances between electrodes (2-3.5 cm), layering of zinc oxide nanoparticles (1-3), and voltages (10-40). The findings showed the correlation between removal of cells and UV-A lamps, voltage, and time of electrolysis. Optimal removal (MPN: 0) was obtained at pH 8, time of electrolysis: 5 minutes, 2 layer of nano ZnO, and voltage of 10 V. This result offers that this method is an efficient method for water disinfection. @JASEMKeywords: Escherichia Coli , Water disinfection, Electrophotocatalytic, UV- AJ. Appl. Sci. Environ. Manage. Sept, 2011, Vol. 15 (3) 439 - 44

    In vitro impact of hydro-alcoholic extract of Rosa damascena Mill. On rat ileum contractions and the mechanisms involved

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    Background: The petal's hydro-alcoholic extract of Rosa damascena Mill. on ileum contractions of Wistar rats and its possible mechanism were investigated. Methods: Forty-eight male Wistar rats were divided into six groups. Ileum was placed adjacent to propranolol (1 μM), naloxone (1 μM) and L-NAME (100 μM) and also under the influence of different doses (2-8 mM) of calcium chloride. Results: Cumulative extract of R. damascena Mill. (100, 500, and 1000 mg/L) decreased ileum contractions induced by KCl (60 mM) in a dose-dependent manner (P < 0.0001). Propranolol and naloxone significantly decreased the inhibitory effect of the extract on contractions induced by KCl (P < 0.001), but L-NAME was ineffective. Furthermore, calcium led to the contraction of depolarized tissue through KCI and this contractile effect decreased significantly induced by the cumulative concentrations of the extract (P < 0.001). Conclusions: The results indicate that R. damascena Mill. dose-dependently (100, 500, and 1000 mg/L) decreases ileum movements of the rat probably through stimulating the β-adrenergic and opioid receptors and voltage-dependent calcium channels, and it may be used to treat digestive disorders

    Alkali ratio control for lead-free piezoelectric thin films utilizing elemental diffusivities in RF plasma

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    High performance piezoelectric thin films are generally lead-based, and find applications in sensing, actuation and transduction in the realms of biology, nanometrology, acoustics and energy harvesting. Potassium sodium niobate (KNN) is considered to be the most promising lead-free alternative, but it is hindered by the inability to control and attain perfect stoichiometry materials in the thin film form while using practical large area deposition techniques. In this work, we identify the contribution of the elemental diffusivities in the radio frequency (RF) plasma in determining the alkali loss in the KNN thin films. We have also examined the effect of the substrate temperature during the RF magnetron sputtering deposition on the crystal structure of the substrate and KNN thin films, as well as the effect of the postannealing treatments. These results indicate the need for well-designed source materials and the potential to use the deposition partial pressure to alter the dopant concentrations

    Biology of Parapodia sinaica (Lep.: Gelechiidae) in Qom province

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    Parapodia sinaica Frau. is among one of the important pests of tamarisk (Tamarix spp.) in Qom province. During 2000-2003, the biology of this pest was studied by periodic samplings of its different life stages every 15 days using light traps in natural tamarisk fields (Masileh region - Qom salt lake) and rearing some life stages in transparent dishes containing a tamarisk stem in laboratory conditions (50 ± 5% RH, 25 ± 1ºC and a photoperiod of 16L: 8D h.). P. sinaica overwinters as 4th or 5th larval instars in the galls. In early March, larvae change into pupa and the pupal period lasts 52 ± 5 and 44 ± 3 days in field and laboratory conditions, respectively. Flight peak of the adult moth took place in early May. The moth being fed on water and sugar survived 14 ± 3 days and preoviposition period lasted 2.3 ± 0.49 days. Average egg number deposited by a female in natural conditions was 32 ± 7. Oviposition period lasted 7.2 ± 0.83 days and incubation period of eggs was 29 ± 3 and 25 ± 2 days in the field and laboratory conditions, respectively. This insect has five larval instars and the mean developmental time of the first to the fifth larval instars were 63 ± 5, 46 ±.34, 44 ± 3.8, 50 ± 5.3 and 97 ± 6.2 days, respectively. The pest has one generation in a year. Larvae never feed on the wood but they feed on bark and cause die back of the branches in the end of the next year. Activity of this pest was also observed in Isfahan, Khuzestan, Qom and Yazd provinces

    Pulmonary artery banding in the current era: Is it still useful?

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    Background: The objective of this study was to assess the results of the pulmonary artery (PA) banding in patients with congenital heart defects (CHD) and pulmonary hypertension (PH) in the current era. Methods: We analyzed data from 305 patients who underwent PA banding between April 2005 and April 2010 at our centre. All patients were approached through a left thoracotomy. Twenty percent of patients underwent PA banding based on Trusler's rule (Group 1), 55 of them underwent PA banding based on PA pressure measurement (Group 2), and the rest of them (25) based on surgeon experience (Group 3). The follow-up period was 39 ± 20 month and 75 of patients (230 cases) had definitive repair at mean interval 23 ± 10 months. Results: The rate of anatomically and functionally effectiveness of PA banding in all groups was high (97 and 92, respectively). There were no significant differences in anatomically and functionally efficacy rate between all groups (P=0.77, P=0.728, respectively). There was PA bifurcation stenosis in six cases (2), and pulmonary valve injury in one case (0.3). The mortality rate in PA banding was 2 and in definitive repair was 3. Conclusions:We believe that PA banding still plays a role in management of patients with CHD, particularly for infants with medical problems such as sepsis, low body weight, intracranial hemorrhage and associated non cardiac anomalies. PA banding can be done safely with low morbidity and mortality

    Experimental Study of Natural Convective Flow over a Hot Horizontal Rhombus Cylinder Immersed in Water via PIV Technique

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    Natural convective flow over a horizontal cylinder is a phenomenon used in many industries such as heat transfer from an electrical wire, heat exchanger, pipe heat transfer, etc. In this research, fluid dynamics of natural convective flow over a horizontal rhombus cylinder, with uniform heat flux, is investigated by using two-dimensional Particle Image Velocimetry (PIV) Technique. Experiments are carried out in a cubical tank full of water having an interface with air and the cylinder is placed horizontally inside the tank. The heater is turned on for 40s and the effects of heater's power and the height of water above the cylinder are surveyed. The experiments are carried out in three different heights of water and two different heater’s powers in which Rayleigh number changes from 1.33×107 to 1.76×107. The emitted heat flux causes the buoyancy force to be made and the main branch of flow to be formed. Then, moving up the main branch flow through the stationary water generates two equal anti-direction vortexes. These vortexes are developed when they reach the free surface. The results indicate that the flow pattern changes for different values of water height and heater’s power

    Transparent functional oxide stretchable electronics: micro-tectonics enabled high strain electrodes

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    Fully transparent and flexible electronic substrates that incorporate functional materials are the precursors to realising nextgeneration devices with sensing, self-powering and portable functionalities. Here, we demonstrate a universal process for transferring planar, transparent functional oxide thin films on to elastomeric polydimethylsiloxane (PDMS) substrates. This process overcomes the challenge of incorporating high-temperature-processed crystalline oxide materials with low-temperature organic substrates. The functionality of the process is demonstrated using indium tin oxide (ITO) thin films to realise fully transparent and flexible resistors. The ITO thin films on PDMS are shown to withstand uniaxial strains of 15%, enabled by microstructure tectonics. Furthermore, zinc oxide was transferred to display the versatility of this transfer process. Such a ubiquitous process for the transfer of functional thin films to elastomeric substrates will pave the way for touch sensing and energy harvesting for displays and electronics with flexible and transparent characteristics

    High-performance field effect transistors using electronic inks of 2D molybdenum oxide nanoflakes

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    Planar 2D materials are possibly the ideal channel candidates for future field effect transistors (FETs), due to their unique electronic properties. However, the performance of FETs based on 2D materials is yet to exceed those of conventional silicon based devices. Here, a 2D channel thin film made from liquid phase exfoliated molybdenum oxide nanoflake inks with highly controllable substoichiometric levels is presented. The ability to induce oxygen vacancies by solar light irradiation in an aqueous environment allows the tuning of electronic properties in 2D substoichiometric molybdenum oxides (MoO3-x). The highest mobility is found to be approximate to 600 cm(2) V-1 s(-1) with an estimated free electron concentration of approximate to 1.6 x 10(21) cm(-3) and an optimal I-On/I-Off ratio of &gt;10(5) for the FETs made of 2D flakes irradiated for 30 min (x = 0.042). These values are significant and represent a real opportunity to realize the next generation of tunable electronic devices using electronic inks

    Cosmology from LOFAR Two-metre Sky Survey Data Release 2: Angular Clustering of Radio Sources

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    Covering ∼5600 deg2 to rms sensitivities of ∼70−100 μJy beam−1, the LOFAR Two-metre Sky Survey Data Release 2 (LoTSS-DR2) provides the largest low-frequency (∼150 MHz) radio catalogue to date, making it an excellent tool for large-area radio cosmology studies. In this work, we use LoTSS-DR2 sources to investigate the angular two-point correlation function of galaxies within the survey. We discuss systematics in the data and an improved methodology for generating random catalogues, compared to that used for LoTSS-DR1, before presenting the angular clustering for ∼900,000 sources ≥1.5 mJy and a peak signal-to-noise ≥7.5 across ∼80% of the observed area. Using the clustering we infer the bias assuming two evolutionary models. When fitting {angular scales of 0.5≤θ&lt;5°, using a linear bias model, we find LoTSS-DR2 sources are biased tracers of the underlying matter, with a bias of bC=2.14+0.22−0.20 (assuming constant bias) and bE(z=0)=1.79+0.15−0.14 (for an evolving model, inversely proportional to the growth factor), corresponding to bE=2.81+0.24−0.22 at the median redshift of our sample, assuming the LoTSS Deep Fields redshift distribution is representative of our data. This reduces to bC=2.02+0.17−0.16 and bE(z=0)=1.67+0.12−0.12 when allowing preferential redshift distributions from the Deep Fields to model our data. Whilst the clustering amplitude is slightly lower than LoTSS-DR1 (≥2 mJy), our study benefits from larger samples and improved redshift estimates
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