Canal Surfaces with Quaternions

Quaternions are more usable than three Euler angles in the three dimensional Euclidean space. Thus, many laws in different fields can be given by the quaternions. In this study, we show that canal surfaces and tube surfaces can be obtained by the quaternion product and by the matrix representation. Also, we show that the equation of canal surface given by the different frames of its spine curve can be obtained by the same unit quaternion. In addition, these surfaces are obtained by the homothetic motion. Then, we give some results.     

Organic vapor sensing properties and characterization of α-naphthylmethacrylate LB thin films

Determination of organic vapor sensing properties of α-Naphthylmethacrylate (α-NMA) monomer based Langmuir-Blodgett (LB) thin films was aimed in this study. LB thin film fabrication was performed on quartz glass and quartz crystal substrates in order to investigate the characterization and organic vapor properties of α-NMA materials by using UV-Visible, Atomic Force Microscopy (AFM) and Quartz Crystal Microbalance (QCM) techniques. π-A isotherm graph was taken and a suitable surface pressure value were primarily determined as 13?mN m^?1 for successful α-NMA LB thin film fabrication. Transfer ratio value was found to be ≥ 0.93 for quartz glass and quartz crystal substrates. The typical frequency shift per layer was obtained as 16.93?Hz/layer and the deposited mass onto a quartz crystal was calculated as 271.30?ng/layer (1.02?ng mm^?2). The sensing responses of α-NMA LB films against dichloromethane, chloroform, toluene and m-xylene were measured by QCM system. Dichloromethane created the maximum shift in the resonance frequency than other organic vapors used in this study. Results exhibited that α-NMA LB thin films were potential candidates for organic vapor sensing applications, especially high sensitive detection of dichloromethane at room temperature.     

Effect of CNT incorporation on PAN/PPy nanofibers synthesized by electrospinning method

In this study, carbon nanotubes (CNTs) added polyacrylonitrile/polypyrrole (PAN/PPy) electrospun nanofibers were produced. Average diameters of the nanofibers were measured as 268 and 153 nm for 10 and 25 wt% of PPy contents, respectively. A relatively higher strain to failure values (23.3%) were observed for the low PPy content. When as-grown CNTs (1 and 4 wt%) were added into the PAN/PPy blends, disordered nanofibers were observed to form within the microstructure. To improve the interfacial properties of CNTs/PAN/PPy composites, CNTs were functionalized with H₂SO₄/HNO₃/HCl solution. The functionalized CNTs were well dispersed within the nanofibers and aligned along the direction of nanofibers. Therefore, beads formation on nanofibers decreased. The impedance of the nanofibers was found to decrease with the PPy content and CNT addition. These nanofibers had a great potential to be used as an electrochemical actuator or a tissue engineering scaffold.     

Photophysical behavior of a novel 4-aza-indole derivative in different solvents: reverse solvatochromism

Research on Chemical Intermediates - The photophysical properties of a new 4-aza-indole derivative [ethyl...     

Renal replacement lipomatosis: MR findings in one case

Replacement lipomatosis of the kidney is the result of severe atrophy or destruction of the renal parenchyma, often caused by calculous disease with secondary marked proliferation of renal sinus, renal hilus, and perirenal fatty tissue. Different diagnostic tools have been used to define this entity, with ultrasonography (US), i.v. pyelography (IVP) and computed tomography (CT) used most commonly. We report MR urography and MR appearance of replacement lipomatosis in a 38-year-old man. We think that it combines the advantages of IVP, US and CT.     

Effects of different acid functional groups on proton conductivity of polymer‐1,2,4‐triazole blends

Proton transfer reactions under anhydrous conditions have attracted remarkable interest due to chemical energy conversions in polymer electrolyte membrane fuel cells. In this work, 1H‐1,2,4‐triazole (Tri) was used as a proton solvent in different polymer host matrices such as Poly(vinylphosphonic acid) (PVPA), and poly(2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid) (PAMPS). PVPATri_x and PAMPSTri_x electrolytes were investigated where x is the molar ratio of Tri to corresponding polymer repeat unit. The interaction between polymer and Tri was studied via FTIR spectroscopy. Thermogravimetry analysis and differential scanning calorimetry were employed to examine the thermal stability and homogeneity of the materials, respectively. PVPATri_1.5 showed a maximum water‐free proton conductivity of 2.3 × 10^?3 S/cm at 120 °C and that of PAMPSTri₂ was 9.3 × 10^?4 S/cm at 140 °C. The results were interpreted in terms of different acidic functional groups and composition. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3315–3322, 2006     

A novel turn-on fluorometric “reporter-spacer-receptor” chemosensor based on calix[4]arene scaffold for detection of cyanate anion

Herein, a novel calix[4]arene compound, which was modified by the 2-(2-aminophenyl)benzothiazole fragment with cyanate recognition function was designed based on the reporter-spacer-receptor sensing system. The construction was done via two-step reaction, and the desired sensor 4 was characterized by FT-IR, ¹H-, ¹³C-NMR, and fluorescence spectroscopy along with HRMS data. The sensor candidate showed distinct fluorometric cyanate detection by means of reporter feature of selected benzothiazole constituent. In the presence of cyanate, the sensor gave a turn-on-type fluorescence at 482 nm with a large stokes' shift. Furthermore, it was observed that our fluoroionophore 4 is highly selective toward cyanate over remaining anions such as sulfate, phosphate, fluoride, chloride, bromide, iodide, chlorate, and nitrate in 10% aqueous solution of DMSO. The 1:2 stoichiometric ratio of the 4 -cyanate complex was given the best fit with Job's plot based on the titration data. The association constant (K_a) of sensor 4 with cyanate is determined to be 1.64 × 10⁵ M⁻². The obtained limit of detection (LOD) value for cyanate anion, 312 nM, clearly revealed the remarkable sensitivity of the chemosensor 4 . This supramolecular method provides a highly adaptive technique for the detection of cyanate and so cyanide ions by current international standard methods.     

Polymer electrolyte membranes based on p‐toluenesulfonic acid doped poly(1‐vinyl‐1,2,4‐triazole): Synthesis,thermal and proton conductivity properties

Throughout this work, the synthesis, thermal as well as proton conducting properties of acid doped heterocyclic polymer were studied under anhydrous conditions. In this context, poly(1‐vinyl‐1,2,4‐triazole), PVTri was produced by free radical polymerization of 1‐vinyl‐1,2,4‐triazole with a high yield. The structure of the homopolymer was proved by FTIR and solid state ¹³C CP‐MAS NMR spectroscopy. The polymer was doped with p‐toluenesulfonic acid at various molar ratios, x = 0.5, 1, 1.5, 2, with respect to polymer repeating unit. The proton transfer from p‐toluenesulfonic acid to the triazole rings was proved with FTIR spectroscopy. Thermogravimetry analysis showed that the samples are thermally stable up to ～250 °C. Differential scanning calorimetry results illustrated that the materials are homogeneous and the dopant strongly affects the glass transition temperature of the host polymer. Cyclic voltammetry results showed that the electrochemical stability domain extends over 3 V. The proton conductivity of these materials increased with dopant concentration and the temperature. Charge transport relaxation times were derived via complex electrical modulus formalism (M*). The temperature dependence of conductivity relaxation times showed that the proton conductivity occurs via structure diffusion. In the anhydrous state, the proton conductivity of PVTri1PTSA and PVTri2PTSA was measured as 8 × 10^?4 S/cm at 150 °C and 0.012 S/cm at 110 °C, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1016–1021, 2010     

Can Hg(II) be Determined via Quenching of the Emission of Green Fluorescent Protein from <Emphasis Type="Italic">Anemonia sulcata</Emphasis> var. <Emphasis Type="Italic">smaragdina</Emphasis>?

Anemonia sulcata var. smaragdina is a widely distributed Cnidarian species along Turkish coastlines. It is also a well-known example of a facultative symbiotic life form in sea ecosystems. Green fluorescent proteins (GFPs) in Anemonia sulcata var. smaragdina have vital roles in this symbiotic form. The fluorescence quenching by Hg(II) in the supernatants obtained from A. sulcata var. smaragdina was shown in this study. According to results, there was a statistical significant relationship (R ² = 0.9913) between increased Hg(II) concentration and decreased fluorescence intensity of GFP supernatants obtained from A. sulcata var. smaragdina. Mn(II), Fe(II), and Al(II) showed no interference effect and did not change the fluorescence intensity of GFP supernatants obtained from A. sulcata var. smaragdina. In conclusion, the fluorescence quenching of GFPs by Hg(II) can be a novel method to determine the Hg(II) levels in aqueous solution. Therefore, further researches are strongly warranted because of the possible potential applications of the fluorescence quenching of GFPs by Hg(II).