Genotyping of the Helicobacter pylori isolates of raw milk and traditional dairy products

Notwithstanding the substantial clinical impact of Helicobacter pylori, its convinced routes of transmission and sources have not been reported. Based on the quarrelsome hypothesis, foods and especially dairy products play an authoritative role in the transmission of H. pylori to humans. The current investigation was done to study the prevalence rate and distribution of vacA genotypes in the H. pylori strains isolated from the raw milk and traditional dairy products. Three-hundred milk and dairy samples were collected and directly transported to laboratory. Samples were cultured and H. pylori isolates were approved using the 16s rRNAbased PCR amplification. Positive strains were tested for distribution of vacA genotypes using the multiplex-PCR. Sixty out of 300 samples (20%) harbored H. pylori. Prevalence of H. pylori in milk and traditional dairy products were 38.75% and 13.18%, respectively. Ovine milk (45%) and traditional cheese (40%) had the highest prevalence of H. pylori. VacAs1a (91.66%), vacAm1a (61.61%) vacAs2 (36.66%) and vacAm2 (31.66%) were the most commonly detected genotypes. Ovine milk and traditional cheese had the most diverse genotypes. S1am1a (41.66%), s2m1a (25%), s1am2 (16.66%) and s2m2 (13.33%) were the most commonly detected combined genotypes. Raw milk and traditional dairy products are latent sources of H. pylori. Similarity in the genotyping pattern of H. pylori strains of various samples represents their similar sources of infection. Further studies are required to found the exact sources of H. pylori strains in raw milk and traditional dairy products

Brain diffusion MRI biomarkers after oncology treatments

In addition to providing a measurement of the tumor’s size and dimensions, magnetic resonance imaging (MRI) provides excellent noninvasive radiographic detection of tumor location. The MRI technique is an important modality that has been shown to be useful in the prognosis, diagnosis, treatment planning, and evaluation of response and recurrence in solid cancers. Diffusion-weighted imaging (DWI) is an imaging technique that quantifies water mobility. This imaging approach is good for identifying sub-voxel microstructure of tissues, correlates with tumor cellularity, and has been proven to be valuable in the early assessment of cytotoxic treatment for a variety of malignancies. Diffusion tensor imaging (DTI) is an MRI method that assesses the preferred amount of water transport inside tissues. This enables precise measurements of water diffusion, which changes according to the direction of white matter fibers, their density, and myelination.  This measurement corresponds to some related variables: fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD), and others. DTI biomarkers can detect subtle changes in white matter microstructure and integrity following radiation therapy (RT) or chemoradiotherapy, which may have implications for cognitive function and quality of life. In our study, these indices were evaluated after brain chemoradiotherapy

Comparing the ZnO/Fe(VI), UV/ZnO and UV/Fe(VI) processes for removal of Reactive Blue 203 from aqueous solution

Background: Wastewater contaminated with dyes such as Reactive Blue 203 can produce a lot of health problems if it is released into the environment without a suitable treatment. Although there are several studies on dye removal from wastewater, removal of Reactive Blue 203 has not been investigated by hybrid methods. Therefore, the aim of this study was to investigate the removal of Reactive Blue 203 from aqueous solution, using combined processes of zinc oxide (ZnO) nanoparticles, Fe(VI) oxidation process, and UV radiation. Methods: The removal of dye from aqueous solution using ZnO nanoparticles, Fe(VI) oxidation process, and UV radiation was individually evaluated. Then, the results of combined methods were compared. Hydraulic retention time (HRT), pH, and temperature were the most important factors which were investigated in this study. Results: ZnO nanoparticles, Fe(VI) oxidation process, and UV radiation were able to remove 97%, 71%, and 47% of the dye in the optimal conditions, respectively. Also, the removal of dye using combination of Fe(VI) oxidation process/UV radiation, ZnO nanoparticles/Fe(VI) oxidation process, and ZnO nanoparticles/UV radiation under optimum conditions was 100%. It seems that the combined methods were significantly more effective than the methods alone for removal of dye from water. Conclusion: UV radiation alone is a simple and efficient method for removal of Reactive Blue 203 from water. Removal of Reactive Blue 203 using Fe(VI) oxidation process can be completed in a fraction of second, therefore, it can be categorized as a rapid reaction. Keywords: Wastewater, Ultraviolet rays, Zinc oxide, Adsorptio

Removal of Acid Orange 7 dye from wastewater using combination of ultraviolet radiation, ultrasonic method, and MgO nanoparticles

Background: Industrial dyes are toxic and carcinogenic, therefore, they should be removed from wastewater. The aim of this study was to investigate the removal of acid orange 7 Dye from wastewater using ultraviolet (UV) radiation, MgO nanoparticles, ultrasonic method alone and in combination with each other. Methods: The effects of some factors such as temperature, pH, hydraulic retention time (HRT), UV power, and concentration of MgO nanoparticles on the removal of Acid Orange 7 dye from synthetic wastewater using different methods were investigated. Also, adsorption isotherms for MgO nanoparticles and kinetics for UV radiation were investigated. Results: The optimum HRT was 55 minutes while the temperature was not effective in dye removal using the ultrasonic method. Under optimum conditions for UV irradiation method (HRT = 70 minutes, UV power = 170 mW/cm2, and temperature = 10˚C), 58% of the dye was removed. However, under optimum conditions for MgO nanoparticles method (HRT = 15 minutes, temperature = 20˚C, and ratio of MgO nanoparticles to the initial dye concentration = 67.2), 82% of the dye was removed. By combining these methods, the dye removal efficiency was significantly increased. The combination of ultrasonic method and MgO nanoparticles had no significant effect on increasing the dye removal efficiency from wastewater. It was revealed that dye removal using UV radiation can be described by the first-order kinetics. Conclusion: According to the results, UV radiation has a synergistic effect on the dye adsorption process by MgO nanoparticles. Therefore, the combination of these methods can be effective for the removal of dye from wastewater. Keywords: Azo compounds, Ultraviolet rays, Ultrasonic method, Nanoparticles, Waste water, Kinetic

Experimental and theoretical studies of the effect of nanofluids on cryogenic processes

The present research examines the thermophysical properties and heat transfer performance of water-based nanofluids, WEG-based nanofluids (50:50 mixture of water and ethylene glycol), and LN2-based nanofluids (Liquid Nitrogen). The nanofluids were produced using a variety of nanoparticles, including Cu purchased from VWR as metallic nanoparticles, Fe3O4 synthesized via precipitation method as metal oxides nanoparticles, MWCNT, and Nano Porous Graphene (NPG) synthesized via a CVD method as nonmetallic (carbon-based) nanoparticles, in the volume concentration 0.01-0.1vol%, using different surfactants. The particles were characterized using several analytical techniques. X-ray powder diffraction (XRD) was employed to determine the crystal structure and identify the phases of metallic and metal oxide nanoparticles. Scanning electron microscopy (SEM) was used to visualize and analyze the morphology and size distribution of the nanoparticles. Specific surface area was measured using the BET method to evaluate the surface properties of the nanoparticles. Dynamic light scattering (DLS) provided information about the size distribution of particles in the nanofluids.The density, viscosity, thermal conductivity, and surface tension of base fluids and nanofluids were measured experimentally and theoretically at temperatures ranging from -20°C to 20°C. Additionally, through the measurement of heat capacity in a temperature range of 80 to 350 K, a set of fascinating data was obtained for various nanoparticles. These data were subsequently used to develop several correlations that can be incorporated into equations for cryogenic nanofluids. The convective heat transfer enhancement of water-based and WEG-based nanofluids in a pipe heat exchanger used for the ethanol condensation process is investigated in this work at relevant temperatures of 20°C and -20°C, respectively. Convective heat transfer enhancement under a laminar regime was evaluated from a well-designed experimental setup. Heat transfer efficiency of LN2-based nanofluids was tested experimentally using a miniature stainless steel cylindrical heater under atmospheric pressure in a very cold region (-196°C) and compared to different correlations in both the nucleate (II region) and film boiling (IV region) regimes. The thermophysical properties of nanofluids are strongly influenced by the type and concentrations of nanoparticles, the type of surfactant, and temperatures, especially at low temperatures, according to the key findings. As the main results, the thermal conductivity of nanofluids increases up to 3-5% (water-based nanofluids) and 4-14% (WEG-based nanofluids). e.g. with 0.1 vol%, the thermal conductivity of Fe3O4 nanofluids increases by nearly 9.5%, and 14.3%, at -10°C and 20°C, respectively. The thermal conductivity enhancement of nanofluids with concentration and temperature was compared to some relevant theoretical models. While no clear proof for physical phenomena involving such an enhancement has been discovered, a reasonable agreement is obtained using a comprehensive model that incorporates effective medium theory, the nanolayer effect of molecules surrounding the solid particle, and Brownian motion of nanoparticles that includes aggregation and nano-convection.The viscosity can increase or decrease with nanoparticle concentration, showing a lubricating effect of nanoparticles coupled with respective surfactants. For all temperatures, except for lower ones (-20°C), Newtonian behavior of water and WEG-based nanofluids are reported in the range -20°C to 20°C. The addition of MWCNT and NPG nanoparticles did not result in any noticeable change in viscosity. On the other hand, the presence of surfactants and L-ascorbic acid as physical and chemical stabilizers in Cu and Fe3O4 nanofluids led to a decrease in viscosity with an increase in nanoparticle content. E.g. it is also found that the dynamic viscosity of Fe3O4 WEG-based nanofluids decreases with nanoparticle content in particular below 0°C, up to 40% at 0.1% in volume. Surface tension decreases by adding the surfactant to the base fluid and then increases with Fe3O4 concentration with nearly 38% and 33% with 0.1% in nanoparticle volume fraction at -20°C and 20°C, respectively. The heat transfer properties, including the heat transfer coefficient and Nusselt number, of nanofluids were found to be significantly higher than those of water and WEG-based fluids (0.05 vol%). This increase was observed to be up to 20% and 55% for Pe 2000-10000 and Gz (Graetz number) 40-300, respectively. For example, at low Pe and Gz numbers, the Nusselt numbers for Cu and Fe3O4 nanofluids in water-based fluids were increased by approximately 18% and 29%, respectively. In addition, the Nusselt numbers for Cu and Fe3O4 nanofluids in WEG-based fluids were enhanced by around 30% and 24%, respectively. Experimental heat transfer properties were shown to be greater than theoretical ones. Increasing in heat transfer coefficient is observed by adding the nanoparticles. Finally, these results are promising in view of Cu water-based and Fe3O4 WEG-based nanofluids use in cooling applications and pipe flow geometry considered. It is also noticeable that the heat transfer coefficient of LN2-based and nanofluids has risen as the Jacob number has increased, and that nanofluids have higher heat transfer coefficients than liquid nitrogen, with the exception of Cu nanofluids at low Jacob numbers. At the maximum Ja numbers (around 7.5), the rises for Cu, Fe3O4, MWCNT, and NPG (0.1 vol%) nanofluids are 22, 40, 42, and 14%, respectively. The average heat transfer coefficient improvements for Cu, Fe3O4, MWCNT, and NPG (0.1 %) LN2-based nanofluids are 77, 35, 22, and 27% in the IVa region (Ra = 0.9-2×109), and 35, 15, 9, and 17% in the IVb region (Ra = 2-9×108) at cryogenic temperatures, respectively. Finally, the best candidate nanofluid for cryogenic applications is Cu nanofluids. Overall, this research provides valuable insights into the thermophysical properties and heat transfer performance of nanofluids, suggesting their potential application in cooling systems.Doctorat en Sciences de l'ingénieur et technologieinfo:eu-repo/semantics/nonPublishe

Amine-functionalized Zr-MOF/CNTs nanocomposite as an efficient and reusable photocatalyst for removing organic contaminants

In the current study, a new water-stable nanocomposite and amine-functionalized zirconium-based metal-organic framework/carbon nanotube (UiO-66-NH2@CNT) was synthesized using the hydrothermal approach, displaying superior photodegradation of anionic and cationic dyes under visible-light irradiation. Methyl orange (MO) and Rhodamin B (RhB) were used as organic contaminant models. The prepared materials were fully characterized by FTIR, XRD, SEM, TEM, BET, TGA, UV–Vis absorption, and ICP analysis. The optimal nanocomposite, UiO-66-NH2@CNT(3 wt%) exhibited the highest degradation efficiency of RhB (100%) and MO (93%) in less than 30 min under optimum conditions in comparison with other prepared materials (F-CNT, UiO-66, Ui-66-NH2, and other UiO-66-NH2@CNT-X samples). Different effective parameters such as initial dye concentration, catalyst dosage, and solution pH have been also studied. The possible mechanism for photodegradation of dyes over UiO-66-NH2@CNT(3 wt%) showed that the increase in the photocatalytic activity can be attributed to the range of improved visible-light absorption (lower band gap), and the great specific surface area based on composite and water stability as well as the formation of an effective hetero-junction. Trapping studies also revealed that hydroxyl radicals (OH•) and photo-generated holes (h+) had the most influence on the photocatalytic degradation of both dyes. The kinetic study for the dye degradation process was fitted with a first-order kinetic model. Also, after six-reuse cycles, the optimum composite still showed high photodegradation ability (>90%). © 2021 Elsevier B.V

The developing flow characteristics of water - ethylene glycol mixture based Fe3O4 nanofluids in eccentric annular ducts in low temperature applications

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The Developing Natural Convection Visualization of Water - Ethylene Glycol Mixture based Fe3O4 Nanofluids in Eccentric Annular Ducts in Low Temperature Applications

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Heat transfer properties of metal, metal oxides, and carbon water-based nanofluids in the ethanol condensation process

International audienceThis work investigates the convective heat transfer enhancement of water-based nanofluids in pipe heat exchanger used for the ethanol condensation process. The nanofluids were produced with different nature of nanoparticles, Cu, Fe3O4, MWCNT, and graphene, in the volume concentration 0.01–0.1%, using different surfactants. These nanoparticles are characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), specific surface area (BET), and Dynamic light scattering (DLS). Density, thermal conductivity, and viscosity of base fluids and nanofluids were experimentally determined at a relevant temperature of 20 °C. Convective heat transfer enhancement under laminar regime was evaluated from a well-designed experimental setup. As the main results, the thermal conductivity of nanofluids increases up to 3–5% and the viscosity can increase or decrease with nanoparticle concentration, showing a lubricating effect of nanoparticles coupled with respective surfactant. It was shown that the heat transfer properties, heat transfer coefficient, and Nusselt number, are increased with nanofluids compared to water and base-fluids, up to 20%, in the range of Pe 2000–10000. Experimental heat transfer properties are shown to be greater than theoretical ones. Finally, copper nanofluid at low concentration appear to be the best candidate for the application and pipe flow geometry considered