Static magnetic fields aggravate the effects of ionizing radiation on cell cycle progression in bone marrow stem cells

In order to evaluate the influence of static magnetic fields (SMF) on the progression of cell cycle as a monitor of presumptive genotoxicity of these fields, the effects of a 15 mT SMF on cell cycle progression in rat bone marrow stem cells (BMSC) were examined. The cells were divided into two groups. One group encountered SMF alone for 5 h continuously but the other group exposed with X ray before treatment with SMF. The population of cells did not show any significant difference in the first group but the second group that was exposed with acute radiation before encountering SMF showed a significant increase in the number of cells in G₂/M phase. So SMF has intensified the effects of X ray, where SMF alone, did not had any detectable influence on cell cycle.These findings suggest that magnetic fields (MF) play their role by increasing the effects of genotoxic agents and because of the greater concentration of free radicals in the presence of radical pair producers, this effect is better detectable.     

Development of a Sensitive Methodology for the Analysis of Chlorobenzenes in Water Samples by Combination of Homogeneous Liquid‐liquid Microextraction via Flotation Assistance and Gas Chromatography‐flame Ionization Detection

In this study, a simple, rapid and efficient method, homogeneous liquid‐liquid microextraction via flotation assistance (HLLME‐FA) combined with gas chromatography – flame ionization detection (GC‐FID), for the determination of chlorobenzenes (CBs) in water samples, has been described. In this research, a special extraction cell was designed to facilitate collection of the low‐density solvent extraction. No centrifugation was required in this procedure. The water sample solution was added into the extraction cell which contained an appropriate mixture of extraction and homogeneous solvents. By using air flotation, the organic solvent was collected at the conical part of the designed cell. Parameters affecting extraction efficiency were investigated and optimized. Under the optimum conditions, the detection limits, the precisions and the linearity of the method were found in the range of 0.2 to 1.5 µg L^‐1, 5.7–9.3% (RSD, n =5) and 0.5–200 µg L^‐1, respectively.     

Alteration in the Mechanical Properties of Human Ovum Zona Pellucida Following Fertilization: Experimental and Analytical Studies

The unfertilized oocyte is surrounded by a spherical layer called the zona pellucida (ZP). The physical hardness of this layer plays a crucial role in fertilization and it is largely unknown because of the lack of appropriate measuring and modeling methods. Recently, considerable biomedical attentions have concentrated on determination of the mechanical properties of oocytes as a single cell. In order to investigate the biophysical characteristics of mammalian oocytes, a change in the elasticity of human ZP has been quantitatively evaluated before and after fertilization. Young’s modulus of ZP of metaphase-II (MII) and pronuclear (PN) stages have been estimated using two different protocols of the micropipette aspiration, step-by-step and continuous increase in pressure, in combination with proportional theoretical models. Experimental results clearly demonstrated that after fertilization the mean Young’s modulus of the ZP calculated from the step-by-step aspiration test (MII: 7.34 ± 1.36 kPa vs PN: 13.18 ± 1.17 kPa.) and continuous aspiration test (MII: 2.41 ± 0.75 kPa vs. PN: 4.43 ± 1.66 kPa) significantly increased, (p < 0.05). Mathematical Evaluation of the results shows that although the results of the two methods are different but both confirm that the hardening of ZP will increase following fertilization. As can be seen, different experimental methods can influence the choice of the models and this in turn will lead the mechanical properties to be found.     

Synthesis of nanoporous TiO2 materials using a doubly surfactant system and applying them as useful adsorbents

Hydrothermal and non-hydrothermal nanoporous TiO₂ materials were synthesized via a doubly surfactant route by using cationic cetyltrimethylammonium bromide and anionic sodium dodecyl sulfate surfactants as the molecular template/structure directing agent. Hydrothermal treatment was performed for comparison. The bulk chemical and phase compositions, crystalline structures, particle morphologies, thermal stabilities and surface texturing were determined by means of X-ray powder analysis, SEM and N₂ sorptiometry. The nanoporous TiO₂ materials were found to have a spherical morphology with a diameter range of 50–200 nm and a high surface area (390 m² g^?1). Hydrothermal and non-hydrothermal nanoporous TiO₂ materials were applied for adsorption of heavy metal cations and the toxic organic compound, copper phthalocyanine, from water for evaluation of their adsorption properties. Both nanoporous TiO₂ materials were found to have similar adsorption capacities toward heavy metal cations and CuPc. Both hydrothermal and non-hydrothermal TiO₂ nanoporous materials were found to have very good potential for application as a new adsorbent especially for adsorbing heavy metal cations from wastewaters.     

Heat Transfer and Hydrodynamic Performance Analysis of a Miniature Tangential Heat Sink Using Al2O3–H2O and TiO2–H2O Nanofluids

In this article, thermal and hydrodynamic performances of a miniature tangential heat sink are investigated experimentally by using Al₂O₃–H₂O and TiO₂–H₂O nanofluids. The effects of flow rate and volume concentration on the thermal performance have been investigated for the Reynolds number range of 210 to 1,100. Experimental results show that the average convective heat transfer coefficient increases 14 and 11% and the bottom temperature of the heat sink decreases 2.2°C and 1.6°C by using Al₂O₃–H₂O and TiO₂–H₂O nanofluid instead of pure distilled water, respectively.     

Spectral and crystallography studies of new palladacycle complexes with P,C‐ and C,C‐donor ligands; Application of (OAL16) to optimizing the yield of Mizoroki‐Heck reaction

The new symmetrical diphosphonium salt [Ph₂P(CH₂)₂PPh₂(CH₂C(O)C₆H₄Br)₂] Br₂ ( S ) was synthesized in the reaction of 1,2‐bis (diphenylphosphino) ethane (dppe) and related ketone. Further treatment with NEt₃ gave the symmetrical α‐keto stabilized diphosphine ylide [Ph₂P(CH₂)₂PPh₂(CHC(O)C₆H₄Br)₂] ( Y ¹ ). The unsymmetrical α‐keto stabilized diphosphine ylide [Ph₂P(CH₂)₂PPh₂(CHC(O)C₆H₄Br)] ( Y ² ) was synthesized in the reaction of diphosphine in 1:1 ratio with 2.3′‐dibromoacetophenone, then treatment with NEt_3. The reaction of dibromo (1,5‐cyclooctadiene)palladium (II), [PdBr₂(COD)] with this ligand ( Y ¹ ) in equimolar ratio gave the new C,C‐chelated [PdBr₂(Ph₂P(CH₂)₂PPh₂(C(H)C(O)C₆H₄Br)₂)] ( 1 ) and with unsymmetrical phosphorus ylide [Ph₂P(CH₂)₂PPh₂C(H)C(O)C₆H₄Br] ( Y ² ) gave the new P, C‐chelated palladacycle complex [PdBr₂(Ph₂P(CH₂)₂PPh₂C(H)C(O)Br)] ( 2 ). These compounds were characterized successfully by FT‐IR, NMR (¹H, ¹³C and ³¹P) spectroscopic methods and the crystal structure of Y ¹ and 2 were elucidated by single crystal X‐ray diffraction. The results indicated that the complex 1 was C, C‐chelated whereas complex 2 was P, C‐chelated. These air/moisture stable complexes were employed as efficient catalysts for the Mizoroki‐Heck cross‐coupling reaction of several aryl chlorides, and the Taguchi method was used to optimize the yield of Mizoroki‐Heck coupling. The optimum condition was found to be as followed: base; K₂CO₃, solvent; DMF and loading of catalyst; 0.005 mmol.     

Electrochemical investigations of the various electrolytes for high energy density metal oxide supercapacitor

Journal of Solid State Electrochemistry - In this work, the asymmetric supercapacitor (ASC) devices with three different electrolytes including aqueous, organic, and gel polymer electrolytes have...     

Pyrrolizidine Alkaloids-Free Extract from the Cell Culture of Lithospermum officinale with High Antioxidant Capacity

The benefits of Lithospermum officinale has encouraged people to continue using its extract (CAS 90063-58-4) in both medicinal and cosmetic industries despite the fact that chemical analysis confirms the presence of pyrrolizidine alkaloids (PAs) in the extract. While the cultivation of L. officinale takes, at least, 2 years to produce usable crops, its callus culture proliferated 8.3 times with 4.9-fold biomass in less than 30 days under the applied conditions in this study. Under the applied conditions, the cell extract contained no toxic PAs while phenylpropanoid pathway was active toward phenolic acids formation not toward naphthoquinone derivatives. Rosmarinic acid was produced as the main constituent. Total phenolic content and antioxidant capacity of the proliferated cell extracts were similar to those of the extracts of the natural plant tissues, in particular from the root. These results support the idea that the extract of L. officinale cells can be a reliable substitute for the extract of the natural plant tissues.

     

A highly selective and sensitive cocaine aptasensor based on covalent attachment of the aptamer-functionalized AuNPs onto nanocomposite as the support platform

Based on the conformational changes of the aptamer-functionalized gold nanoparticles (AuNPs) onto MWCNTs/IL/Chit nanocomposite as the support platform, we have developed a sensitive and selective electrochemical aptasensor for the detection of cocaine. The 5′-amine-3′-AuNP terminated aptamer is covalently attached to a MWCNTs/IL/Chit nanocomposite. The interaction of cocaine with the aptamer functionalized AuNP caused the aptamer to be folded and the AuNPs with negative charge at the end of the aptamer came to the near of electrode surface therefore, the electron transfer between ferricyanide (K₃Fe(CN)₆) as redox probe and electrode surface was inhibited. A decreased current of (K₃Fe(CN)₆) was monitored by differential pulse voltammetry technique. In an optimized condition the calibration curve for cocaine concentration was linear up to 11 μM with detection limit (signal-to-noise ratio of 3) of 100 pM. To test the selectivity of the prepared aptasensor sensing platform applicability, some analgesic drugs as the interferes were examined. The potential of the aptasensor was successfully applied for measuring cocaine concentration in human blood serum. Based on our experiments it can be said that the present method is absolutely beneficial in developing other electrochemical aptasensor.