172 research outputs found

    Development of Photonic Crystal Fiber Based Gas/ Chemical Sensors

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    The development of highly-sensitive and miniaturized sensors that capable of real-time analytes detection is highly desirable. Nowadays, toxic or colorless gas detection, air pollution monitoring, harmful chemical, pressure, strain, humidity, and temperature sensors based on photonic crystal fiber (PCF) are increasing rapidly due to its compact structure, fast response and efficient light controlling capabilities. The propagating light through the PCF can be controlled by varying the structural parameters and core-cladding materials, as a result, evanescent field can be enhanced significantly which is the main component of the PCF based gas/chemical sensors. The aim of this chapter is to (1) describe the principle operation of PCF based gas/ chemical sensors, (2) discuss the important PCF properties for optical sensors, (3) extensively discuss the different types of microstructured optical fiber based gas/ chemical sensors, (4) study the effects of different core-cladding shapes, and fiber background materials on sensing performance, and (5) highlight the main challenges of PCF based gas/ chemical sensors and possible solutions

    Characteristics of Copper-based Oxygen Carriers Supported on Calcium Aluminates for Chemical-Looping Combustion with Oxygen Uncoupling (CLOU)

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    Eight different oxygen carriers (OC) containing CuO (60 wt %) and different mass ratios of CaO to Al2O3 as the support were synthesized by wet-mixing followed by calcination at 1000 °C. The method of synthesis used involved the formation of calcium aluminum hydrate phases and ensured homogeneous mixing of the Ca2+ and Al3+ ions in the support at the molecular level. The performance of the OCs for up to 100 cycles of reduction and oxidation was evaluated in both a thermogravimetric analyzer (TGA) and a fluidized bed reactor, covering a temperature range of 800 to 950 °C. In these cycling experiments, complete conversion of the OC, from CuO to Cu and vice versa, was always achieved for all OCs. The reactivity of the materials was so high that no deactivation could be observed in the TGA, owing to mass transfer limitations. It was found that OCs prepared with a mass ratio of CaO to Al2O3 in the support >0.55 agglomerated in the fluidized bed, resulting in an apparent deactivation over 25 cycles for all temperatures investigated. High ratios of mass of CaO to Al2O3 in the support resulted in CuO interacting with CaO, forming mixed oxides that have low melting temperatures, and this explains the tendency of these materials to agglomerate. This behavior was not observed when the mass ratio of CaO to Al2O3 in the support was ≤0.55 and such materials showed excellent cyclic stability operating under redox conditions at temperatures as high as 950 °C.The authors thank Mohammad Ismail and Matthew Dunstan for helping with the XRD analysis and Alex Casabuena-Rodriguez and for helping with the SEM. This work was supported by the Engineering and Physical Sciences Research Council (EPSRC grant EP/I010912/1).This is the final version of the article. It first appeared from ACS via http://dx.doi.org/10.1021/acs.iecr.5b0117

    Spiral ligament fibrocyte-derived MCP-1/CCL2 contributes to inner ear inflammation secondary to nontypeable H. influenzae-induced otitis media

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    <p>Abstract</p> <p>Background</p> <p>Otitis media (OM), one of the most common pediatric infectious diseases, causes inner ear inflammation resulting in vertigo and sensorineural hearing loss. Previously, we showed that spiral ligament fibrocytes (SLFs) recognize OM pathogens and up-regulate chemokines. Here, we aim to determine a key molecule derived from SLFs, contributing to OM-induced inner ear inflammation.</p> <p>Methods</p> <p>Live NTHI was injected into the murine middle ear through the tympanic membrane, and histological analysis was performed after harvesting the temporal bones. Migration assays were conducted using the conditioned medium of NTHI-exposed SLFs with and without inhibition of MCP-1/CCL2 and CCR2. qRT-PCR analysis was performed to demonstrate a compensatory up-regulation of alternative genes induced by the targeting of MCP-1/CCL2 or CCR2.</p> <p>Results</p> <p>Transtympanic inoculation of live NTHI developed serous and purulent labyrinthitis after clearance of OM. THP-1 cells actively migrated and invaded the extracellular matrix in response to the conditioned medium of NTHI-exposed SLFs. This migratory activity was markedly inhibited by the viral CC chemokine inhibitor and the deficiency of MCP-1/CCL2, indicating that MCP-1/CCL2 is a main attractant of THP-1 cells among the SLF-derived molecules. We further demonstrated that CCR2 deficiency inhibits migration of monocyte-like cells in response to NTHI-induced SLF-derived molecules. Immunolabeling showed an increase in MCP-1/CCL2 expression in the cochlear lateral wall of the NTHI-inoculated group. Contrary to the <it>in vitro </it>data, deficiency of MCP-1/CCL2 or CCR2 did not inhibit OM-induced inner ear inflammation <it>in vivo</it>. We demonstrated that targeting MCP-1/CCL2 enhances NTHI-induced up-regulation of MCP-2/CCL8 in SLFs and up-regulates the basal expression of CCR2 in the splenocytes. We also found that targeting CCR2 enhances NTHI-induced up-regulation of MCP-1/CCL2 in SLFs.</p> <p>Conclusions</p> <p>Taken together, we suggest that NTHI-induced SLF-derived MCP-1/CCL2 is a key molecule contributing to inner ear inflammation through CCR2-mediated recruitment of monocytes. However, deficiency of MCP-1/CCL2 or CCR2 alone was limited to inhibit OM-induced inner ear inflammation due to compensation of alternative genes.</p

    Examination and Comparison of Various Methods of DNA Extraction from Samples of Blood, Bone Marrow Slides and Peripheral Blood

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    Introduction: DNA extraction methods are very important for genetics research and diagnostic tests. In These methods are also important for detecting genetic diseases or in cancers for investigating genetic changes during cancer progression or treatment. Therefore, selection of the best method for DNA extraction from different samples such as bone marrow (BM) or peripheral blood (PB) and their slides is very important. Methods: In the present research, DNA was extracted from 5 different samples including; 1-PB, 2-BM slides stained by Gimsa method, 3-Gimsa stained PB slides from archives, 4-new Gimsa stained PB slides and 5-non stained new PB slides by 3 different methods; salting-out, boiling and phonal chloroform method. In all of the groups, three DNA parameters were investigated; 1-OD (Optimal Density), 2-DNA concentration and 3-Outcome (PCR results). Results: The best DNA quality was achieved by salting-out method (OD=1.74), while the worst quality was by the boiling method (OD<1.0). The DNA quality of all the samples was similar in the salting-out and phenol chloroform methods. Regarding DNA quantity, the best result was from boiling method (6.7µg / ml). The least amount of DNA was obtained by the phenol chloroform method and salting-out method also resulted in the least quantity of extracted DNA. Regarding the outcome of DNA extraction or the PCR results, all the three methods showed 100% positive results for peripheral blood samples, while boiling method had the best outcome for BM slides, archive stained PB slides, new stained PB slides and non-stained PB slides (100%, 88%, 84% and 72% respectively). Discussion: The present research indicated that except non stained PB slides, the DNA extraction from all other samples showed very good results. In addition, the research showed that there is no difference in DNA extraction of new or archive slides

    Animal Bioavailability of Defined Xenobiotic Lignin Metabolites.

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    Lignin has been recognized as a major component of bound pesticide residues in plants and is thought to be undigestible in animals. Two defined ring-U-14C-labeled chloroaniline/lignin metabolites have now been fed to rats, where a release of &sim;66% of the bound xenobiotic occurred in the form of simple chloroaniline derivatives. The observed high degree of bioavailability indicates that bound pesticidal residues may possess ecotoxicological significance. In parallel studies, the white-rot fungus Phanerochaete chrysosporium was more efficient, and a soil system was much less efficient, in the degradation of the [ring-U-14C]chloroaniline/lignin metabolites
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