M-Ali H. Al-Akhras

Optimizing the tilt angle of solar collectors

Solar collectors need to be tilted at the correct angle to maximize the performance of the system. In this paper, the annual solar fraction of the system (the fraction of energy that is supplied by solar energy) is used as an indicator to find the optimum inclination angles for a thermosyphon solar water heater installed in northern and southern parts of Jordan. Calculations are carried out using the powerful computer program TRNSYS (Transient System Simulation). The system is assumed to operate with a daily hot water load of 150 l at 55°C flowing during the day according to the widely used Rand consumption profile. The results show that the optimum inclination angle for the maximum solar fraction is about φ+(0→10°) for the northern region (represented by Amman) and about φ+(0→20°) for the southern region (represented by the town of Aqaba). These values are greater than those for maximum solar radiation (which is commonly used as an indicator) at the top of the collector by about 5 to 8°.

Magnetic nanoparticles sensitize MCF-7 breast cancer cells to doxorubicin-induced apoptosis

BackgroundResistance of breast cancer cells to the available chemotherapeutics is a major obstacle to successful treatment. Recent studies have shown that magnetic nanoparticles might have significant application in different medical fields including cancer treatment. The goal of this study is to verify the ability of magnetic nanoparticles to sensitize cancer cells to the clinically available chemotherapy.MethodsThe role of iron oxide nanoparticles, static magnetic field, or a combination in the enhancement of the apoptotic potential of doxorubicin against the resistant breast cancer cells, MCF-7 was evaluated using the MTT assay and the propidium iodide method.ResultsIn the present study, results revealed that pre-incubation of MCF-7 cells with iron oxide nanoparticles before the addition of doxorubicin did not enhance doxorubicin-induced growth inhibition. Pre-incubation of MCF-7 cells with iron oxide nanoparticles followed by a static magnetic field exposure significantly (P < 0.05) increased doxorubicin-induced cytotoxicity. Sensitization with pre-exposure to the magnetic field was dose-dependent where the highest cytotoxicity was seen at 1 tesla. Further experiments revealed that the anti-proliferative effect of this treatment procedure is due to induction of apoptotic cell death.ConclusionsThese results might point to the importance of combining magnetic nanoparticles with a static magnetic field in treatment of doxorubicin-refractory breast cancer cells.

Hybrid Zinc Oxide Nanorods/Carbon Nanotubes Composite for Nitrogen Dioxide Gas Sensing

This study reports on the synthesis and fabrication of hybrid nanocomposite based on single-walled carbon nanotubes–ZnO nanorods (SWCNT-ZnONR) as resistive gas sensors for NO2 detection. The sensor was prepared using the standard simple and cost-effective hydrothermal process. The sensor was characterized by x-ray diffraction (XRD) and scanning electron microscopy. The findings revealed enhanced porous SWCNT-ZnONR nanocomposites due to the high porosity of the SWCNT. It was also found that the sensor exhibited average response and recovery times of about 70 s and 100 s, respectively. The XRD peak at 26° indicated that the SWCNT pattern was not disturbed, while sensitivity increased with temperature up to 150°C, at which the sensitivity was maximum. Similarly, the sensor sensitivity increased with NO2 concentration at all levels examined. Moreover, the results indicate that the sensor shows significant promise for NO2 gas sensing applications.

Mössbauer and structural studies of Fe0.7−xVxAl0.3 alloys

Abstract We report the Mossbauer and structural studies of the alloy system Fe 0.7− x V x Al 0.3 where x =0, 0.02, 0.06, 0.1, 0.2, and 0.3. X-ray diffraction indicates that all the samples studied have single phase with body center cubic structure. The lattice parameter ( a ) increases with increasing the vanadium concentration. Room temperature Mossbauer studies show magnetic ordering for small values of x and paramagnetic behavior for large values of x . The Mossbauer spectra were fitted by a distribution of magnetic hyperfine fields for small values of x and two singlets were added for large values of x . The relation between the hyperfine field and the isomer shift in the hyperfine field distribution is linear. The average hyperfine field and isomer shift were found to decrease with increasing V concentration. The results are interpreted in terms of local environmental effects on the hyperfine interactions.

Ultraviolet photodetector based on ZnO nanorods grown on a flexible PDMS substrate

A flexible, reproducible, sensitive and low-cost ultraviolet (UV) detector has been fabricated based on zinc oxide (ZnO) nanorods grown on a patterned polydimethylsiloxane (PDMS) substrate. The substrate was seeded with ZnO nanoparticles synthesised via simple low-temperature hydrothermal method using pomegranate peel extract as a reducing agent. The produced ZnO-nanorods/PDMS (ZnO-NR/PDMS) samples were tested for their UV-sensing properties. Samples were characterised using scanning electron microscopy, X-ray diffraction, I–V characteristics, UV-Vis spectroscopy and photoluminescence measurements. The UV photoresponse mechanism of prototype UV detector was analysed. The detector exhibited quite high on/off ratios between photoresponse current and dark current. With the flexible PDMS substrate, the detector photoresponse was tested with and without bending and exhibited a very slight change in the photoresponse current. The detector current–time response was also tested under various UV light intensities for three test cycles to examine the detector stability, hysteresis behaviour and performance. It is anticipated that the fabrication of ZnO-NR/PDMS UV detector may have significant potential application in flexible optoelectronic devices.

Introducing Cichorium Pumilum as a Potential Therapeutical Agent Against Drug-Induced Benign Breast Tumor in Rats

Cichorium Pumilum (chicory) is could be a promising cancer treatment in which a photosensitizing drug concentrates in benign tumor cells and activated by quanta at certain wavelength. Such activated extracts could lead to cell death and tumor ablation. Previous studies have shown that Cichorium Pumilum (chicory) contains photosensitive compounds such as cichoriin, anthocyanins, lactucin, and Lactucopicrin. In the present study, the protective effect of sun light-activated Cichorium against the dimethylbenz[a]anthracene (DMBA) induced benign breast tumors to female Sprague-Dawley rats was investigated. Chicorys extract has significantly increase P.carbonyl (PC) and malondialdehyde (MDA) and decreases the hepatic levels of total antioxidant capacity (TAC) and superoxide dismutase (SOD) in benign breast tumors-induced group compared to control. It also significantly decrease the number of estrogen receptors ER-positive cells in tumor masses. These results suggest that chicory extracts could be used as herbal photosensitizing agent in treating benign breast tumor in rats.

A prototype Ultraviolet Light Sensor based on ZnO Nanoparticles/Graphene Oxide Nanocomposite Using Low Temperature Hydrothermal Method

A new prototype UV nanosensor using ZnO nanoparticles (NPs)/graphene oxide (GO) nanocomposite (ZnO-NP/GO) on silicon substrate is reported in this paper. The hybrid nanocomposite structure has been developed by an optimized hydrothermal process at low growth temperature (~50 °C). In this hybrid nanosensor, the ZnO nanoparticles act as UV- absorbing and charge carrier generating material, while graphene with its superior electrical conductivity has been used as a charge transporting material. Various nanostructure characterization techniques were intensively utilized including SEM, EDX, XRD, FTIR and UV-VIS. Also, the I-V measurement was employed to evaluate the prototype sensor. The morphological SEM analysis showed that the ZnO-NPs (average diameter of 20 nm) were dispersed evenly on the GO sheets. As well, the EDX spectra confirmed the exact chemical composition of the intended structure. The room temperature UV-VIS measurement revealed an enhanced optical absorption of UV-light at an absorption band centered on 375 nm. The improved optical and electrical properties were observed at an optimum relative concentration of 1:10. Under UV light illumination, the measured I-V characteristic of the prototype detector exhibited a considerable photocurrent increase of the ZnO-NP/GO nanocomposite compared to pristine ZnO nanostructure. These results can be promising for future enhanced UV- sensing applications.

Enhanced nanocurcumin toxicity against (PC3) tumor and microbial by using magnetic field in vitro

Abstract Curcumin is more soluble in ethanol, dimethylsulfoxide, methanol and acetone than in water. In this study, nanocurcumin combined with 8 mT AC static magnetic field was used to enhance cellular uptake, bioavailability, and ultimate efficiency of curcumin against prostate cancer cell line (PC3), four bacteria strains (two Gram positive: Micrococcus luteus ATCC 9341, Staphylococcus aureus ATCC 29213 and two Gram negative: Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853), mammalian cell line (HEK) and human erythrocytes (RBC). The efficiency (E%) between IC50 of nanocurcumin combined with magnetic field (NANOCUR-MF) and control against PC3 was 35.93%, which is three times higher compared to curcumin combined with magnetic field (CUR-MF); i.e., 10.77%. However, their E% against HEK was not significant; 1.4% for NANOCUR-MF and 1.95% for CUR-MF. Moreover, depending in minimum bacterial concentration (MBC), the use of MF leads to a reduction of MBCs for all tested bacteria compared with control. The obtained results established the applicability of (MF) in enhancing cellular uptake for PC3 and tested bacteria strains by increasing the penetration of drug (nanocurcumin and parent curcumin) into cell with fixing mild cytotoxic profile for HEK and RBC.

Influence of iron oxide nanoparticles (Fe3O4) on erythrocyte photohemolysis via photofrin and Rose Bengal sensitization

BACKGROUND Iron oxide (Fe3O4) nanoparticles (IO-NP) were recently employed in medical applications as a diagnostic tool and drug carrier. Photofrin (PF) is a photosensitizer that clinically is used in Photodynamic therapy (PDT). STUDY DESIGN The photosensitivity of PF and Rose Bengal (RB) mixed with (IO-NP) on red blood cells (RBCs) lysis was investigated. Second, Photohemolysis for post-irradiation (delayed) and during irradiation (continuous) with PF, RB and IO-NP combinations at different concentrations was investigated. Third, the photohemolysis rate, relative lysis steepness and power-concentration dependant parameter were evaluated by modeling and fitting the data using Gompertz function and power law. METHODS RBCs were isolated from healthy male human volunteer. Washed cells (7.86×106 cells/mm3) were incubated with PF only or with IO-NP for 45min at 37°C then irradiated to a range of temperatures (4-41°C). CPH results were recorded and evaluated using Gompertz function. RESULTS The relative steepness of the photohemolysis curves was approximately independent on light dose for delayed irradiation. The presence of IO-NP increases the rupturing time for 50% of the RBCs. Photohemolysis rate for delayed irradiation using the power law, led to 1.7 and 2.3 power dependence, respectively, for PF only and PF mixed with IO-NP. The power dependence of continuous irradiation measurements showed inverse proportionality for different concentrations of IO-NP combined with 2μg/ml PF concentration and 1.5μg/ml for RB concentration. CONCLUSION Photosensitization of RBC with PF or RB mixed with IO-NP inhibited rupturing erythrocyte membrane and therefore a consideration should be taken against their combination in clinical applications.

Continuous and Delayed Photohemolysis Sensitized With Methylene Blue and Iron Oxide Nanoparticles (Fe3O4)

This research present the sensitization of methylene blue (MB), as a potential photodynamic therapy photo sensitizer which showed phototoxicity for many tumor cells in vitro incorporated with iron oxide nanoparticles (Fe3O4, IO-NP), which offer magnificent interaction both inside and outside the surface of biomolecules together with red blood cells (RBCs) with significant change in hemolysis process. The study investigated the sensitization of continuous photohemolysis (CPH) for MB and MB with IO-NP, delayed photohemolysis (DPH) at different irradiation temperature (Tirr). The photohemolysis rate for CPH at room temperature has a power dependence of 0.39 ± 0.05 with relative of steepness of 1.25 ± 0.02 and for different concentration of MB and power dependent of 0.15 ± 0.03 with relative steepness of 1.34 ± 0.01 for different MB and IO-NP. Logistic and Gompertz functions were applied as appropriate mathematical models to fit the collected experimental data for CPH and DPH respectively, and to calculate fractional photohemolysis rate with minimum errors. The Logistic function parameter; α, the hemolysis rate, increases with increasing concentrations of MB and decreases with increasing IO-NP concentrations in the presence of 6 μg/ml of MB. The parameter β; the time required to reduce the maximum number of RBCs to one half of its value, decreases with increasing MB concentration and increases with increasing IO-NP concentrations in the presence of 6 pg/ml of MB. In DPH at different Tirr, the Gompertz parameter; a, fractional hemolysis ratio, is independent of temperature in both case MB and MB plus IO-NP, while the parameter; b, rate of fractional hemolysis change, increases with increasing Tirr, in both case MB and MB plus IO-NP. The apparent activation energy of colloid-osmotic hemolysis is 9.47±0.01 Kcal/mol with relative steepness of 1.31 ± 0.05 for different MB and 6.06±0.03 Kcal/mol with relative steepness of 1.41 ± 0.09 for MB with iron oxide. Our results suggest that Logistic equation is the best fit for the CPH and Gompertz function for the DPH. Both models predict also that the relative steepness is independent of the light dose, sensitizer and IO-NP concentrations.