Review: the latest advances in biomedical applications of chitosan hydrogel as a powerful natural structure with eye-catching biological properties

Journal of Materials Science - Chitosan is one of the natural cationic polymers with unique properties such as non-toxicity, biodegradability, biocompatibility, environmentally friendly that has...     

Wall Rock Alteration,Uranium Mineralization,and Potentiality of Uranium and Iron Dissolution from Mineralized Abu Rusheid Gneiss Rock,South Eastern Desert,Egypt

Radiochemistry - Ferrugination, sericitization, desulfitization, chloritization, and kaolinitization of hydrothermal origin are the main wall rock alterations occurring within the NNW shear zones...     

Effect of pH and zeta potential of Pickering stabilizing magnetite nanoparticles on the features of magnetized polystyrene microspheres

Styrene as a monomer was emulsified in water using several magnetite nanoparticles concentration and pH values. Emulsified styrene drops were used as templates for polymerization, in presence of water soluble free radical initiator, and formation of composite particles. Styrene template drops stabilization was verified by light as well as scanning electron microscopy imaging, which ensured the participation of the particles in building up a mechanical barrier to stop oil drops coalescence. Furthermore, the produced polystyrene composites were strongly attracted to an external magnet. The difference in particles size as a function of pH was elucidated using zeta potential measurements, which indicated dominance of pH on the hydrophilicity of the particles and consequently the extent of emulsification, which in turn affected the size of the obtained microspheres. Under some circumstances, capsules were formed instead of particles. Thereby, it can be concluded that the magnetic microspheres are optimally formed at pH 2.3 independently of the magnetite content used.     

Determination of Ethopabate Residues in Chicken Muscles, Liver, and Eggs after Aqueous SDS Extraction by Micellar Liquid Chromatography with Fluorescence Detection with Application to Baby Food

A simple and sensitive liquid chromatographic method was optimized and validated for the analysis of ethopabate residues in chicken muscles, liver, and eggs. Aqueous sodium dodecyl sulfate (SDS) solution was used for extraction. Analytical separation was performed in less than 8 min using a C18 column (150?×?4.6 mm internal diameter, 5 μm particle size) with fluorescence detection at 271/364 nm. A micellar solution composed of 0.1 M SDS, 10 % 1-propanol, and 0.3 % triethylamine in 0.02 M phosphoric acid adjusted to pH?4 was used as the mobile phase. The method was fully validated in accordance with International Conference on Harmonization guidelines. The micellar method was successfully applied to quantitatively determine ethopabate residues in spiked chicken muscles, liver, and eggs. It was also extended to the determination of ethopabate residues in chicken-based baby food. The recoveries obtained were in the 93.81–115.67 % range. The limit of detection was found to be 1.6 ng/g. High extraction efficiency for ethopabate was obtained without matrix interference and in the subsequent chromatographic determination. No organic solvent was used during the pretreatment step.     

Synthesis and characterization of mesoporous anatase TiO2 nanostructures via organic acid precursor process for dye-sensitized solar cells applications

Titania (TiO₂) nanoparticles have been synthesized using organic precursor technique. The titania nanoparticles were characterized. The results indicated that the prepared titanium oxalate and citrate precursors were transformed to anatase TiO₂ phase at temperature 400 °C for 2 h. Dye-sensitized solar cells were assembled using the prepared nanocrystalline TiO₂ with large surface area. The specific surface area S_BET was 80.9 and 78.6 m²/g using oxalic and citric acids, respectively. The power efficiency was 3.5 and 2.4%. A brief discussion on the possible reasons behind the low power conversion efficiency observed for these type of solar cells was reported.     

Surfactant-assisted hydrothermal synthesis of titania nanoparticles for solar cell applications

Nanostructured anatase TiO₂ powders (~7 nm) with different microstructures have been successfully synthesized using surfactant-assisted hydrothermal route. It can be seen that different morphologies of sphere, flower petal and cauliflower were appeared for the anatase powders formed at hydrothermal temperature 100 °C for 24 h without and with sodium dodecyl sulfate (SDS) and cetyl trimethyl-ammonium bromide (CTAB) as anionic and cationic surfactants, respectively. The specific surface area S_BET was increased from 77.14 m²/g without surfactant to 177.19 m²/g in the presence of SDS as anionic surfactant. The optical properties were measured and the band gap energy of the obtained powders was ~3.3 eV. The UV-absorption band of the anatase phase was at near 295 nm without other observable bands, which proved to exhibit high optical property and might have potential application in solar cells devices.     

Preparation of ZnO nanoparticles using electrodeposition and co-precipitation techniques for dye-sensitized solar cells applications

Zinc oxide thin films have been successfully prepared by co-precipitation and electrodeposition methods onto Fluorinated tin oxide substrate using zinc nitrate aqueous solutions at various bath temperatures (25–75 °C). The deposition of electrodeposition method was conducted using both using linear sweep voltammetry and Chronoamperometric techniques. The effects of solution composition, agitation and bath temperature on the electrochemical measurements and ZnO film characteristics were fully analyzed. The findings reveal that temperature and nitrate ion concentration have a strong promoting effect on ZnO film formation. Moreover, the obtained powders were investigated by X-ray diffraction, Field emission scanning electron microscopy and UV–Vis Spectroscopy. Structural characterization by X-ray diffraction indicates the formation of ZnO phase and the deposited film exhibits the Zincite structure with crystallite size around 51 nm. The photovoltaic performance of dye-sensitized solar cells based on both ZnO prepared by co-precipitation and electrodeposition methods was investigated. A power conversion efficiency (η) of 3.5 % was achieved for the DSSC with co-precipitation ZnO, which is higher than that of the cell with electrodeposition ZnO (2.5 %). Explanations are substantiated by incident photon to electron conversion efficiency curves.     

Structural,magnetic properties,and induction heating behavior studies of cobalt ferrite nanopowders synthesized using modified co-precipitation method

Nanocrystalline cobalt ferrite CoFe₂O₄ powders have been successfully synthesized via modified co-precipitation at low temperature. Obviously, well crystalline CoFe₂O₄ phase was obtained from the precipitated precursors at pH 10 using 5?M NaOH as a base thermally treated at 80°C for 1?h in aqueous medium in the absence and the presence of 1000?ppm cetyl trimethyl ammonium bromide (CTAB) as well as sodium dodecyl sulfate (SDS) as cationic and anionic surfactants, respectively. Meanwhile, the spinel ferrite was observed with the similar conditions using ethylene glycol as an organic solvent. The microstructures of the formed powders exhibited nanospheres like structure with narrow size distribution from 6 to 10?nm. The magnetic properties of the formed cobalt ferrite powders strongly depend on the synthesis conditions. For instance, the highest saturation magnetization (M_s?=?36.2?emu/g) was achieved in the aqueous medium, whereas the lowest saturation magnetization (M_s?=?16.2?emu/g) was accomplished in the ethylene glycol medium. Indeed, heating properties of the CoFe₂O₄ samples in an alternating magnetic field (AMF) at 160?kHz were estimated. Of note, it is clear that the specific heat rate SAR values were in the range from 104.5 to 302.0?W/g at different synthesis conditions, making co-ferrite appropriate for hyperthermia treatment of cancer.     

Stage I ovarian cancer by transvaginal color Doppler sonography: a report of 18 cases

PURPOSE: To evaluate the tolerability and 24 hours efficacy of a new anti-hypertensive drug: cilazapril. METHODS: In an open non comparative study 20 hypertensive patients (16 females, age from 30 to 60 years, average = 49.4) were followed for 6 weeks: 2 wash out and 4 treatment (5 mg OD). Blood pressure (BP) was measured by casual and ambulatory blood pressure monitoring (ABPM) readings. RESULTS: Comparing washout and treatment periods, ABPM averages both for systolic and diastolic BP (mmHg) showed significant decrease in 24 hours, during day and night sub periods. The decrease was not significant between averages considering the "early morning rising pressure" sub period. Heart rate averages showed significant reduction at all sub periods except during night. Adverse effects were mild and resolved spontaneously (n = 3, 15%). CONCLUSION: Cilazapril seems to be efficacious as antihypertensive. Tolerability is excellent. It preserved circadian rhythm despite significantly reducing blood pressure at all periods evaluated except early morning. A bradycardic effect observed mostly during day period should be better evaluated.     

An investigation on the properties of SnO2 nanoparticles synthesized using two different methods

Tin oxide SnO₂ nanoparticles have been synthesized using chemical co-precipitation and solvothermal methods. The structures and morphologies of SnO₂ prepared using both routes were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), fourier infrared absorption spectroscopy (FT-IR), UV–Vis Spectroscopy and BET specific surface area. The XRD patterns showed the presence of the tetragonal structure in the nanometric range and both crystallinity as well as crystal size increased with the increasing in temperature. The size of the produced tin dioxide nanoparticles was from 6.2 to 10.6 nm by solvothermal route while it was from 9.3 to 16.2 nm for nanoparticles by co-precipitation pathway. Furthermore, TEM results showed that the sizes of SnO₂ particles in all powders were tetragonal like structure and the grain size was increased with temperature. FT-IR spectra revealed that intensity of the transverse optical mode of Sn–O stretching vibration was increased with the sintering temperature while the bending vibration of O–Sn–O showed a blue shift. The optical band gap was shifted to a lower energy with increasing temperature due to the improvement of the crystallinity and the value was varied from 2.9 to 4.25 eV. The specific surface area of the as-made SnO₂ in comparison with such calcined samples decreased with increasing the calcination temperature due to the changes in the sample particle size and in the sample crystal phases.