Preparation of guanidine group functionalized magnetic nanoparticles and the application in preconcentration and separation of acidic protein

Guanidine group (Gnd) functionalized magnetic nanoparticles (Fe3O4@SiO2@NH2-Gnd) were synthesized and characterized in this work for the first time. The characterization of Fe3O4@SiO2@ NH2-Gnd nanoparticles was demonstrated by transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectra, vibration sample magnetometer, and zeta potential analyzer. The novel multifunctional nanoparticles were served as a solid-phase extraction sorbent for easy isolation and preconcentration of acidic protein from aqueous solution only using a magnet. Bovine serum albumin (BSA) was selected as a model protein and the main experimental parameters influencing the adsorption and desorption efficiency were investigated and optimized. Under the optimum conditions, the particles reached saturated adsorption within 20 min and exhibited significant specific recognition for the acidic proteins. Fifteen fold enrichment efficiency was achieved and the detection limits was 45 ng x mL(-1) for BSA by capillary electrophoresis (CE). The practical application of the novel nanoparticles as a sorbent for the isolation and preconcentration of acidic proteins from basic proteins was demonstrated by effective separation and enrichment of bovine serum albumin from lysozyme and cytochrome C mixture, which was assayed by CE.     

The Study of (<Emphasis Type="Italic">n,d</Emphasis>) Reaction Cross Sections for Some Medium Weight Targets up to 30 MeV

In this study, neutron incident reaction cross sections for some medium target nuclei ( ⁴⁴ Ca, ⁶⁵ Cu, ⁵⁴ Fe, ⁵⁶ Fe, ⁵⁷ Fe, ⁵⁸ Ni, ⁶⁰ Ni and ⁶⁷ Zn) have been investigated for the (n,d) reaction cross sections. These new calculations on the excitation functions of ⁴⁴ Ca(n,d) ⁴³ K, ⁶⁵ Cu(n,d) ⁴⁴ Ni, ⁵⁴ Fe(n,d) ⁵³ Mn, ⁵⁶ Fe(n,d) ⁵⁵ Mn, ⁵⁷ Fe(n,d) ⁵⁶ Mn, ⁵⁸ Ni(n,d) ⁵⁷ Co, ⁶⁰ Ni(n,d) ⁵⁹ Co and ⁶⁷ Zn(n,d) ⁶⁶ Cu reactions have been carried out up to 30 MeV incident neutron energy. In these calculations, the pre-equilibrium and equilibrium effects have been investigated. The PEQ calculations involve the new evaluated the Geometry Dependent Hybrid model. Equilibrium effects are calculated according to the Weisskopf–Ewing model. By using the new cross sections formulae for (n,d) reactions developed by Aydin et al., the obtained results have been discussed and compared with the available experimental data taken from EXFOR database.     

Antioxidant activity of ginger extract in sunflower oil

The antioxidant activity of dichloromethane extract from ginger was evaluated during 6 months of storage of refined sunflower oil at 25 and 45 °C. Free fatty acid (FFA) content, peroxide value (POV) and iodine value (IV) were used as criteria to assess ginger extract as an antioxidant. After 6 months of storage at 45 °C, sunflower oil containing 1600 and 2400 ppm ginger extract showed lower FFA contents (0.083 and 0.080%) and POVs (24.5 and 24.0 meq kg^?1) than the control sample (FFA contents 0.380%, POV 198.0 meq kg^?1). Sunflower oil containing 200 ppm butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) showed FFA contents of 0.089 and 0.072% and POVs of 26.5 and 24.7 meq kg^?1 respectively after 6 months of storage at 45 °C. Similarly, after 6 months of storage at 45 °C, IVs of sunflower oil containing 1600 and 2400 ppm ginger extract were 80 and 92 respectively, higher than that of the control sample (53). However, IVs of sunflower oil treated with 200 ppm BHA and BHT were 94 and 96 respectively after 6 months of storage at 45 °C. These results illustrate that ginger extract at various concentrations exhibited very strong antioxidant activity, almost equal to that of synthetic antioxidants (BHA and BHT). Ginger extract also showed good thermal stability and exhibited 85.2% inhibition of peroxidation of linoleic acid when heated at 185 °C for 120 min. Therefore the use of ginger extract in foods is recommended as a natural antioxidant to suppress lipid oxidation. © 2003 Society of Chemical Industry     

Composition of the Defensive Secretion in Three Species of European Millipedes

Three European julid species, Cylindroiulus boleti, Leptoiulus trilineatus, and Megaphyllum bosniense, secrete mixtures of up to 12 different quinones. The major components in these species are 2-methoxy-3-methyl-1,4-benzoquinone and 2-methyl-1,4-benzoquinone. 2-Methoxy-5-methylhydroquinone is detected for the first time in the Class Diplopoda. 2-Hydroxy-3-methyl-1,4-benzoquinone, 2,3-dimethoxyhydroquinone, 2-methyl-3,4-methylendioxyphenol, and 2,3-dimethoxy-5-methylhydroquinone are registered for the first time in representatives of the family Julidae. The similar chemical composition of defense secretions in all analyzed European julids and Pacific spirobolids supports the idea of the chemical consistency of defensive compounds in juliform millipedes.     

COMMENTS ON π-ELECTRON CONJUGATION IN THE FIVE-MEMBERED RING OF BENZO-DERIVATIVES OF CORANNULENE

Cyclic conjugation in corannulene and its benzo-derivatives is studied by means of the π-electron contents and the energy effects of individual rings, with particular attention to the structural effects influencing the magnitude of cyclic conjugation in the 5-membered ring. Two main general regularities were observed: (a) the PCP effect (6-membered rings connected by a single bond to the 5-membered ring increase in it the intensity of cyclic conjugation), and (b), the linear effect (6-membered rings separated from the 5-membered ring by another 6-membered ring, but not in PCP constellation, decrease the magnitude of cyclic conjugation in the 5-membered ring).     

Deposition of nanoparticle multilayers to improve mechanical properties of denim fabrics

Al₂O₃ nanoparticles were used for fabrication of multilayer nanocomposite film deposition on cationic denim fabrics by electrostatic self-assembly to improve the mechanical properties. Denim fabrics were pre-treated with 2,3-epoxypropyltrimethylammonium chloride (EP3MAC) by a pad-batch method for cationic surface charge. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy were used to verify the presence of deposit nanolayers. CIELab analysis was performed on the fabrics before and after the treatment with Al₂O₃ nanoparticles by the layer-by-layer (LbL) deposition method. After aging processes, the effect of LbL deposition method on the tensile strength properties of denim fabrics was also investigated.     

Testing software components for integration: a survey of issues and techniques

Component‐based development has emerged as a system engineering approach that promises rapid software development with fewer resources. Yet, improved reuse and reduced cost benefits from software components can only be achieved in practice if the components provide reliable services, thereby rendering component analysis and testing a key activity. This paper discusses various issues that can arise in component testing by the component user at the stage of its integration within the target system. The crucial problem is the lack of information for analysis and testing of externally developed components. Several testing techniques for component integration have recently been proposed. These techniques are surveyed here and classified according to a proposed set of relevant attributes. The paper thus provides a comprehensive overview which can be useful as introductory reading for newcomers in this research field, as well as to stimulate further investigation. Copyright © 2006 John Wiley & Sons, Ltd.     

Enhanced dynamic credential generation scheme for protection of user identity in mobile-cloud computing

To improve the resource limitation of mobile devices, mobile users may utilize cloud-computational and storage services. Although the utilization of the cloud services improves the processing and storage capacity of mobile devices, the migration of confidential information on untrusted cloud raises security and privacy issues. Considering the security of mobile-cloud-computing subscribers’ information, a mechanism to authenticate legitimate mobile users in the cloud environment is sought. Usually, the mobile users are authenticated in the cloud environment through digital credential methods, such as password. Once the users’ credential information theft occurs, the adversary can use the hacked information for impersonating the mobile user later on. The alarming situation is that the mobile user is unaware about adversary’s malicious activities. In this paper, a light-weight security scheme is proposed for mobile user in cloud environment to protect the mobile user’s identity with dynamic credentials. The proposed scheme offloads the frequently occurring dynamic credential generation operations on a trusted entity to keep minimum processing burden on the mobile device. To enhance the security and reliability of the scheme, the credential information is updated frequently on the basis of mobile-cloud packets exchange. Furthermore, the proposed scheme is compared with the existing scheme on the basis of performance metrics i.e. turnaround time and energy consumption. The experimental results for the proposed scheme showed significant improvement in turnaround time and energy consumption as compared to the existing scheme.     

A green separation process for recovery of healthy oil from pumpkin seed

In this study, pumpkin seeds, called as “Ürgüp Sivrisi” and grown in Cappadocia region, were used as plant materials because of high aroma contents. In the supercritical fluid extraction of pumpkin seed oil, the effect of main process parameters as the particle size (250-2360 μm), the volumetric flow rate of supercritical solvent (0.06-0.30 L/h), the operating pressure (20-50 MPa), the operating temperature (40-70 °C), the type of entrainer (ethanol and n-hexane) and those concentrations (0-10 vol.%) on the extraction yield, the oil solubility and the initial extraction rate were investigated. A cross-over effect for the extraction of pumpkin seed oil using supercritical CO₂ was determined at the operating pressure of 20-30 MPa. The maximum extraction yield obtained with entrainer free was reached 0.50 g oil/g dry seed at 600-1180 μm, 0.12 L/h, 50 MPa and 70 °C for the operation time of 5 h. The maximum extraction yield obtained with ethanol as an entrainer in the experiments was reached 0.54 g oil/g dry seed at the conditions of 600-1180 μm, 0.12 L/h, 30 MPa, 40 °C and 8 vol.% for the operating time of 2 h. The oil compositions were determined by gas chromatography analysis and the results showed that the compositions of pumpkin seed oil which were obtained by means of organic solvent extraction and supercritical fluid extraction were similar. The average oil compositions determined as 9.3 (±0.43)% palmitic acid, 7.5 (±0.6)% stearic acid, 32.3 (±0.6)% oleic acid, 48.1 (±0.6)% linoleic acid and 0.7 (±0.3)% linolenic acid. The morphological changes in the seeds were determined by the scanning electron microscopy analysis.     

Modifying of Cotton Fabric Surface with Nano-ZnO Multilayer Films by Layer-by-Layer Deposition Method

ZnO nanoparticle–based multilayer nanocomposite films were fabricated on cationized woven cotton fabrics via layer-by-layer molecular self-assembly technique. For cationic surface charge, cotton fabrics were pretreated with 2,3-epoxypropyltrimethylammonium chloride (EP3MAC) by pad-batch method. XPS and SEM were used to examine the deposited nano-ZnO multilayer films on the cotton fabrics. The nano-ZnO films deposited on cotton fabrics exhibited excellent antimicrobial activity against Staphylococcus aureus bacteria. The results also showed that the coated fabrics with nano-ZnO multilayer films enhanced the protection of cotton fabrics from UV radiation. Physical tests (tensile strength of weft and warp yarns, air permeability and whiteness values) were performed on the fabrics before and after the treatment with ZnO nanoparticles to evaluate the effect of layer-by-layer (LbL) process on cotton fabrics properties.