1,516,984 research outputs found

    Improved time-resolved measurements of inorganic ions in particulate matter by PILS-IC integrated with a sample pre-concentration system

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    A particle-into-liquid sampler coupled with ion chromatograph (PILS-IC) for the on-line measurement of inorganic ions has been modified by the insertion of two ion-exchange pre-concentration cartridges that enrich the sample during the period of the IC analysis. The limits of detection of the modified instrument were 10-15 times lower and the time coverage 24 times higher (from 2 to 48 min per hour) than those of the original PILS-IC setup. The instrumental performance in terms of recovery and break-through volume from the cartridges was satisfactory. The modified PILS-IC was operated in comparison with a diffusion denuder line and with a high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) during a short intensive measurement period organized in the framework of the European Monitoring and Evaluation Programme (EMEP), a co-operative program for monitoring and evaluation of the long-range transmission of the air pollutants in Europe. The instrument showed a quantitative response in agreement with the results of the diffusion lines, and an ability to trace fine concentration variations not so different from the performance of the much more complex HR-TOF-AMS. From the time patterns of the ion concentrations measured by the modified PILS-IC, it was possible to obtain useful information about the variations in the air quality and in the strength of the particulate matter sourc

    Evaluation of Stamark Brand Bisymmetric 1.75 Grade Pavement Marking Tape

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    The objective of this project was to evaluate the performance of Stamark Brand Bisymmetric 1.75 Grade pavement Marking Tape (Series 320) on a large-scale installation on Interstate 24 in McCracken County. The evaluation consisted of periodic inspection of the tape to determine its durability, appearance, and reflectivity. The tape has demonstrated good performance after two years in service. No durability problems were noted. While the appearance of the tape was not as bright as a typical traffic paint, it was adequate. The tape has maintained a high level of reflectivity. The performance of the material would potentially warrant additional use as longitudinal marking on moderate volume roadways. However, the cost of the tape must be considered in determining its use

    Impact of continuous positive airway pressure treatment on left atrial volume and function in patients with obstructive sleep apnoea assessed by real-time three-dimensional echocardiography

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    Background: Obstructive sleep apnoea (OSA) has been reported as a predictor of left ventricle (LV) diastolic dysfunction and left atrium (LA) remodelling. the aim of this study is to evaluate the impact of OSA treatment with a continuous positive airway pressure device (CPAP) on the LA volume and function, as well as on the LV diastolic function.Methods: in total, 56 OSA patients were studied. All patients underwent real-time three-dimensional (RT3DE) and two-dimensional echocardiogram with tissue Doppler evaluation in order to estimate LA volumes, function and LV diastolic performance. A total of 30 patients with an apnoea-hypopnoea index greater than 20 were randomly selected to receive sham CPAP (n = 15) or effective CPAP (n = 15) for 24 weeks. They underwent echo examination on three different occasions: at baseline, after 12 weeks and 24 weeks of CPAP or sham CPAP.Results: in the effective CPAP group we observed the following changes from the baseline to the 24-week echo evaluation: (a) a reduction in the E/E' ratio (10.3 (1.9) to 7.9 (1.3), p = 0.03); (b) an increase in the LA passive emptying fraction (28.8% (11.9%) to 46.8% (9.3%), p = 0.01); and (c) a reduction in the LA active emptying fraction (42.7% (11.5%) to 25.7 (15.7), p<0.01). in the sham group, there were no changes from the baseline to the 24-week echo. We found a positive correlation between 24 week/baseline LA active emptying volume and 24 week/baseline E/E' ratios (r = 0.40, p<0.05) and a negative correlation between 24 week/baseline LA passive emptying volume and 24 week/baseline E/E' ratios (r = 20.53, p<0.05). No significant changes were found on LA total emptying fraction.Conclusion: CPAP improved LV diastolic function and LA passive emptying, but not LA structural variables in OSA patients.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CEPIDAFIPUniversidade Federal de São Paulo, Dept Psychobiol, Discipline Sleep Biol & Med, BR-05021010 São Paulo, BrazilAlbert Einstein Hosp, São Paulo, BrazilUniversidade Federal de São Paulo, Discipline Cardiol, BR-05021010 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psychobiol, Discipline Sleep Biol & Med, BR-05021010 São Paulo, BrazilUniversidade Federal de São Paulo, Discipline Cardiol, BR-05021010 São Paulo, BrazilWeb of Scienc

    Photobioreactor Technologies for High-throughput Microalgae Cultivation

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    The evaluation and optimisation of microalgae cultivation process for biomass, lipid and high value chemicals production requires experimental investigation of several interacting variables. This thesis addresses the development of a range of small-scale photobioreactor technologies and shows how they can be applied for rapid, early stage evaluation and scale-up of microalgae cultivation processes. In particular, the work focuses on the engineering evaluation of a novel shaken miniature photobioreactor (mPBr) and a single-use photobioreactor (SUPBr) that can be adapted for both phototrophic and heterotrophic cultivation. A prototype twin-well mPBr was initially designed and fabricated with light provided from cool white light emitting diodes (LED). This was scaled-out to a 24-well mPBr system (4 mL working volume) on a novel shaken platform. High power warm white LEDs provided a maximum light intensity of 2000 µmolm‾²s‾¹. In both systems, surface aeration (via a semipermeable membrane) and mixing were provided by orbital shaking. Real-time control of temperature, relative humidity and CO2 levels was achieved via incubator level control. Amongst the tested geometries of the mPBr, round base and pyramid base gave the best performance. The mass transfer coefficient (kLa) values in the 24-well were measured between 20 – 88 h‾¹ and visual observation of fluid hydrodynamics showed an increase in total surface area with increased shaking frequency. Negligible evaporation was observed at 90% relative humidity for light intensity of < 400 µmolm‾²s‾¹ and at 32 °C, while light intensity variation across the platform is in the range ± 20 µmolm‾²s‾¹. Evaluation of phototrophic culture kinetics of Chlorella sorokiniana in both mPBr designs showed good reproducibility between wells. The best culture performance occurred at 380 µmolm‾²s‾¹, 300 rpm and 5% CO2, where final biomass concentration and total lipid concentration achieved were 9 ± 0.2 gL‾¹ and 55% w/w respectively. The SUPBr comprised a transparent polymeric CultiBagTM operated on the illuminated rotary shaken platform described above. Mixing time values were determined over the range 40 - 220 rpm and were generally less than 40 s. Hydrodynamic studies showed three distinct flow regimes at various shaking frequencies: in-phase, transitional and out-of-phase. Under optimal flow regime, the highest cell concentrations achieved was 6.7 gL‾¹ ± 0.3. Doubling the total working volume resulted in 35 - 40% reduction in biomass concentration due to an increase in the light path length. Phototrophic scale-up criteria from mPBr to SUPBr was successfully achieved based on light–path length and kLa values. Comparison of final biomass concentrations showed similar performance of 6 ± 0.2 gL‾¹ and comparable total lipid production of 25 – 30% by weight at a light intensity of 180 ± 20 µmolm‾²s‾¹. Furthermore, application of the shaken 24-well system for heterotrophic cultivation of microalgae and scale-up to a 7.5 L stirred tank bioreactor was also shown. Cells were cultured in 24 parallel wells, shake flasks and a 7.5 L bioreactor with working volumes of 4 mL, 100 mL and 4000 mL respectively using glucose (10 gL‾¹) as the main carbon source. Constant k(L)a was chosen as scale-up criteria and the values range between 30 – 60 h‾¹. Final biomass concentrations showed good agreement in the range of 4.5 ± 0.5 gL‾¹ and total lipid production of 43 – 50% by weight for the three systems. Overall, the results show the utility of the mPBr and SUPBr technologies for the rapid evaluation and scale-up of both phototrophic and heterotrophic microalgae cultivation conditions

    Relationship of white and gray matter abnormalities to clinical and genetic features in myotonic dystrophy type 1

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    AbstractBackgroundMyotonic dystrophy type 1 (DM1) represents a multisystemic disorder in which diffuse brain white and gray matter alterations related to clinical and genetic features have been described. We aimed to evaluate in the brain of adult patients with DM1 (i) white and gray matter differences, including cortical-subcortical gray matter volume and cortical thickness and (ii) their correlation with clinical disability, global neuropsychological performance and triplet expansion.MethodsWe included 24 adult genetically-confirmed DM1 patients (14 males; age: 38.5±11.8years) and 25 age- and sex-matched healthy controls (14 males; age: 38.5±11.3years) who underwent an identical brain MR protocol including high-resolution 3D T1-weighted, axial T2 FLAIR and DTI sequences. All patients underwent an extensive clinical and neuropsychological evaluation. Voxel-wise analyses of white matter, performed by using Tract Based Spatial Statistics, and of gray matter, with Voxel-based Morphometry and Cortical Thickness, were carried out in order to test for differences between patients with DM1 and healthy controls (p<0.05, corrected). The correlation between MRI measures and clinical-genetic features was also assessed.ResultsPatients with DM1 showed widespread abnormalities of all DTI parameters in the white matter, which were associated with reduced gray matter volume in all brain lobes and thinning in parieto-temporo-occipital cortices, albeit with less extensive cortical alterations when congenital cases were removed from the analyses. White matter alterations correlated with clinical disability, global cognitive performance and triplet expansions.ConclusionIn patients with DM1, the combined smaller overall gray matter volume and white matter alterations seem to be the main morpho-structural substrates of CNS involvement in this condition. The correlation of white matter differences with both clinical and genetic findings lends support to this notion

    Semen evaluation in river terrapin (Batagur affinis).

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    The Batagur affinis or the southern river terrapin is one of the rarest chelonians in the world, found in the rivers of Malaysia. Over years the population of this species has decreased dramatically. Currently there are no data on the reproductive parameters and performance, to include semen collection and evaluation method, for these species. Therefore, this study documented the first-ever semen collection and evaluation in the freshwater turtle, the Batagur affinis. This study was conducted in December 2010 on 15 male river terrapins. Before electroejaculation, the Batagur affinis were sedated with Ketamine (5 mg/kg) IM and then restrained on a wooden stool. An electrical rectal probe was inserted into the cloaca and stimulated with 1-4 volts electrical stimuli in 5-6 cycles followed by manual stimulation. Semen samples were collected immediately after electrical stimuli and/or after manual stimulation. The results of semen evaluation showed that the average semen volume was 3.3 mL (range 0.85-7.45 mL). The seminal fluid was watery, clear, viscous and slimy to touch. An average sperm motility of 4% (range 0-24%) and average concentration of 2.3 million/mL were observed. The sperms had slightly curved narrow heads and the live sperm percentage was 59%. This study forms the basis for the development of a protocol for semen cryopreservation and artificial insemination in chelonians. The method should contribute to preservation of one of the world’s most critically endangered chelonians

    Endotracheal tubes and fluid aspiration: An in vitro evaluation of new cuff technologies

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    © 2017 The Author(s). Background: Aspiration of subglottic secretions past the endotracheal tube (ETT) cuff is a prerequisite for developing ventilator-associated pneumonia (VAP). Subglottic secretion drainage (SSD) ETTs reduce aspiration of subglottic secretions and have demonstrated lower VAP rates. We compared the performance of seven SSD ETTs against a non-SSD ETT in preventing aspiration below inflated cuffs. Methods: ETTs were positioned vertically in 2 cm diameter cylinders. Four ml of a standard microbial suspension was added above inflated cuffs. After 1 h, aspiration was measured and ETTs demonstrating no leakage were subjected to rotational movement and evaluation over 24 h. Collected aspirated fluid was used to inoculate agar media and incubated aerobically at 37 °C for 24 h. The aspiration rate, volume and number of microorganisms that leaked past the cuff was measured. Experiments were repeated (×10) for each type of ETT, with new ETTs used for each repeat. Best performing ETTs were then tested in five different cylinder diameters (1.6, 1.8, 2.0, 2.2 and 2.4 cm). Experiments were repeated as above using sterile water. Volume and time taken for aspiration past the cuff was measured. Experiments were repeated (×10) for each type of ETT. Results were analysed using non-parametric tests for repeated measures. Results: The PneuX ETT prevented aspiration past the cuff in all experiments. All other ETTs allowed aspiration, with considerable variability in performance. The PneuX ETT was statistically superior in reducing aspiration compared to the SealGuard (p < 0.009), KimVent (p < 0.002), TaperGuard (p < 0.004), Lanz (p < 0.001), ISIS (p < 0.001), SACETT (p < 0.001) and Soft Seal (p < 0.001) ETTs. Of the 4 ETTs tested in differing cylinder sizes, the PneuX significantly reduced aspiration across the range of diameters compared to the SealGuard (p < 0.0001), TaperGuard (p < 0.0001) and KimVent (p < 0.0001) ETTs. Conclusions: ETTs showed substantial variation in fluid aspiration, relating to cuff material and design. Variability in performance was likely due to the random manner in which involutional folds form in the inflated ETT cuff. The PneuX ETT was the only ETT able to consistently prevent aspiration past the cuff in all experiments
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