Near-pole polar diagram of objects and duality

The polar diagram of a set of points in a plane and its extracted dual EDPD were recently introduced for static and dynamic cases. In this paper, the near-pole polar diagram NPPD for a set of points is presented. This new diagram can be considered as a generalization of the polar diagram and has applications in several communication systems and robotics problems. After reviewing the NPPD of points, we solve the problem for a set of line segments and simple polygons in optimal time Θ(n log n), where n is the number of line segments or polygon vertices. We introduce duality for the NPPD of points and identify some applications.     

Cold column trapping-cloud point extraction coupled to high performance liquid chromatography for preconcentration and determination of curcumin in human urine

A cold column trapping-cloud point extraction (CCT-CPE) method coupled to high performance liquid chromatography (HPLC) was developed for preconcentration and determination of curcumin in human urine. A nonionic surfactant, Triton X-100, was used as the extraction medium. In the proposed method, a low surfactant concentration of 0.4% v/v and a short heating time of only 2 min at 70 °C were sufficient for quantitative extraction of the analyte. For the separation of the extraction phase, the resulted cloudy solution was passed through a packed trapping column that was cooled to 0 °C. The temperature of the CCT column was then increased to 25 °C and the surfactant rich phase was desorbed with 400 μL ethanol to be directly injected into HPLC for the analysis. The effects of different variables such as pH, surfactant concentration, cloud point temperature and time were investigated and optimum conditions were established by a central composite design (response surface) method. A limit of detection of 0.066 mg L⁻¹ curcumin and a linear range of 0.22–100 mg L⁻¹ with a determination coefficient of 0.9998 were obtained for the method. The average recovery and relative standard deviation for six replicated analysis were 101.0% and 2.77%, respectively. The CCT-CPE technique was faster than a conventional CPE method requiring a lower concentration of the surfactant and lower temperatures with no need for the centrifugation. The proposed method was successfully applied to the analysis of curcumin in human urine samples.     

Thermodynamic and kinetic studies of As2O3 toxicological effects on human insulin in generation diabetes mellitus

The interaction of arsenic trioxide with human insulin was investigated by circular dichroism (CD), cyclic voltammetry and electrophoresis techniques. The interfacial behavior of insulin in presence of As₂O₃ onto the Ag electrode surface was studied at 310 K in phosphate buffer solution (PBS). According to Far-UV CD spectroscopy results, As₂O₃ caused to decrease in structural compactness and variety of alpha helix into beta structures. Near-UV CD indicated that As₂O₃ dissociates disulfide linkage in insulin structure. The kinetic parameters, including charge-transfer coefficient and apparent heterogeneous electron transfer rate constant were also determined. The thermodynamic parameters of insulin denaturation in presence of arsenic trioxide were calculated and reported. The obtained results indicated strong adsorption of insulin in presence of arsenic trioxide onto the Ag surface via chemisorptions.

     

Co-doping a metal (Cr,Mn, Fe,Co, Ni,Cu, and Zn) on Mn/ZSM-5 catalyst and its effect on the catalytic reduction of nitrogen oxides with ammonia

Selective catalytic reduction (SCR) of NO_x by NH₃ over a series of Mn–M/Z catalysts (M = Cr, Mn, Fe, Co, Ni, Cu, Zn, and Z = the ZSM-5 Zeolite) synthesized by wet impregnation method was investigated. Mn–Fe/Z, Mn–Co/Z, and Mn–Cu/Z catalysts exhibited approximately 100 % NO_x conversion over a wide temperature range (200–360 °C) in a defined atmospheric condition, which was noticeably greater than that of Mn–Cr/Z (340–360 °C). Furthermore, the effect of addition of second metal oxide species to the initial Mn/Z catalyst on the structure of catalysts was studied by several characterization techniques. BET measurements revealed high surface area and pore volume of the Mn–Cu/Z catalyst. In addition, the XRD and UV–Vis DR results showed that addition of co-doped metal oxide species improved the dispersion of metal ions and inhibited crystallization of metal oxides. UV–Vis studies also were in good accordance with DTA/TG results confirming the formation of cobalt oxide and copper oxide clusters in Mn–Co/Z and Mn–Cu/Z catalysts, respectively. The FTIR spectra of pyridine adsorption, in addition, suggested the Mn–Cu/Z catalyst contained the most Lewis acid sites leading to more NO_x adsorption capacity.     

Modified nanoporous silicas for oral delivery of the water insoluble organotin compound: loading and release of methylphenyltin dichloride as an anti-tumor drug model

Different nanoporous silica materials, MCM-41, MCM-48 and SBA-15, were modified by pyridine and their applications for oral drug delivery system were evaluated. These pyridine functionalized nanoporous silicas were loaded with a water insoluble diorganotin(IV) dichloride complex as an antitumor drug model and its release from them were investigated by changing pH. An efficient pH-responsive carrier system was constructed by coordination of the pyridine group in modified nonoporous materials to tin complex. In vitro, releasing of loaded tin complex was studied in three different kinds of fluids, including a simulated gastric medium and a simulated body fluid. The loading and releasing of the diorganotin(IV) dichloride from various modified nanoporous silicas and also a non-porous silica (SiO₂) were investigated, and the results were compared. In addition, the effect of some factors such as pH, time of loading and releasing were investigated through this study.     

Experimental Evaluation of the Influence of the Seawater Characteristics on Spatial and Temporal Variations of the Sound Speed in the Southern Abyssal,Intermediate and Shelf Zones of the Caspian Sea

Acoustical Physics - The results of the evaluation on the spatial and temporal changes of the underwater sound speed in the southern abyssal zone of the Caspian Sea are investigated. Experimental...     

Sonochemical Synthesis and Characterization of the Copper(II) Nanocomplex: DNA- and BSA-Binding,Cell Imaging,and Cytotoxicity Against the Human Carcinoma Cell Lines

The focus of the present work is the preparation of new metal-based nanodrug to overcome limitations of chemotherapy such as poor water solubility of most common chemotherapeutic drugs. The copper(II) complex of 1,2,4-triazine derivatives, [Cu(dppt)₂(H₂O)₂]²⁺ (dppt is 5,6-diphenyl- 3- (2-pyridyl)-1,2,4-triazine), has been synthesized at nano-size by sonochemical method and characterized by FTIR, zetasizer, and scanning electron microscopy (SEM). The interaction of the complex and nanocomplex with fish sperm DNA (FS–DNA) and BSA have been investigated under physiological conditions by a series of experimental methods. The results have indicated that the complex binds to FS–DNA by two biding modes, viz., electrostatic and intercalates into the base pairs of DNA. The competitive study with ethidium bromide (EB) shows that the complex and nanocomplex competes for the DNA–binding sites with EB. Protein binding studies show that the complex and nanocomplex could bind with BSA. The results of synchronous fluorescence of BSA show that additions of the complex affect the microenvironment of both tyrosine and tryptophan residues during the binding process. The in vitro cytotoxicity of the complex (solution in DMSO) and nanocomplex (colloid in H₂O) against the human carcinoma cell lines (MCF-7 and A-549) was evaluated by MTT assay. The results of in vitro cytotoxicity indicate that the complex and nanocomplex have excellent cytotoxicity activity against MCF-7 and A-549. Results of the microscopic analyses of the cancer cells confirm the results of the cytotoxicity.     

<Emphasis Type="SmallCaps">l</Emphasis>-Cysteine-functionalized magnetic nanoparticles (LCMNP): as a magnetic reusable organocatalyst for one-pot synthesis of 9-(1<Emphasis Type="Italic">H</Emphasis>-indol-3-yl) xanthen-4-(9<Emphasis Type="Italic">H</Emphasis>)-ones

l-Cysteine-functionalized magnetic nanoparticles (LCMNP) were introduced as an efficient and magnetically separable organocatalyst for the synthesis of 9-(1H-indol-3-yl) xanthen-4-(9H)-one derivatives. This class of compounds was synthesized via a one-pot three-component coupling reaction of 2-hydroxybenzaldehyde, dimedone, and indole in the presence of catalytic amount of LCMNP under mild and green conditions. High yields, short reaction time, easy workup, using environmental friendly conditions, and magnetic reusable catalyst are the advantages of this synthetic methodology. The LCMNP catalyst was reusable in this reaction at least for 6 times without significant decreasing in its catalytic activity.