Multiparameter Polynomial Adaptive Stabilizers

In 1983 Morse proved, for unknown scalar one-dimensional linearsystems, the nonexistence of rational or polynomial universalstabilizers (UAS). In 1983, Nussbaum gave an example of an analyticUAS. In our paper, it is shown that there exist time-invariantpolynomial UAS's with multidimensional gain adaptation. Thedesign procedure is developed for linear, minimum-phase systemsof relative degree one. Convergence of the closed-loop systemis proved. Some numerical simulations are provided.     

Thermal behaviour of bisitaconimide and reactive diluent blends

Thermal behaviour of blends based on N,N'-bis(4-itaconimidophenyl) ether (IE) and 4,4'-bis(4-allyl-2-methoxyphenoxy) benzophenone (R₁) or 4,4'-bis(2-allylphenoxy) benzophenone (R₂) are described in this paper. The reactive diluent content was varied from 5-50% (mass/mass) in these blends. A decrease in the melting point and exothermic peak temperature was observed with increasing mass percent of reactive diluent. Thermal stability of blends was affected at high mass percentage of reactive diluents. This revised version was published online in August 2006 with corrections to the Cover Date.     

Imido Derivatives of Titanium (IV)

Reactions of titanium(IV) isopropoxide with acetamide, benzamide, and nicotinamide in different stoichiometric ratios in anhydrous benzene yielded imido derivatives of type (PrⁱO)_4-nTi(NHOCR)_n where n = 1, 2, 3, and 4; R = CH₃, C₆H₅, and C₅H₄N. All these complexes are insoluble in common organic solvents suggesting their polymeric nature. All these derivatives, with the exception of three which have characteristic melting points, did not sublime at 250°C in vacuo nor did they appear to decompose appreciably below 300°C. I.R. spectra of these derivatives are discussed.     

Preparation of Silver Nanofluids with High Electrical Conductivity

Silver nanofluids have been prepared by single-step chemical reduction method starting with silver nitrate metal precursor. Electrical conductivity of nanofluids has been investigated, as it has largely been overlooked despite immense technological importance. Extremely low yield nanofluid (0.013 wt%) is found to give high electrical conductivity attributed to smaller size monodisperse nanoparticles obtained (16.3 nm). Increased precursor concentration has lead to high yield and high electrical conductivity. Larger particle sizes obtained are optimized by reducing the yield at high concentration, as well as by dilution. The stability is exceptionally higher than the reported results for copper nanofluids.     

Thiol Modified Chitosan Self-Assembled Monolayer Platform for Nucleic Acid Biosensor

A self-assembled monolayer (SAM) of thiol modified chitosan (SH-CHIT), with thioglycolic acid (TGA) as a modifier to bestow thiol groups, has been prepared onto gold (Au)-coated glass plates for fabrication of the nucleic acid biosensor. The chemical modification of CHIT via TGA has been evidenced by Fourier transform infrared spectroscopy (FT-IR) studies, and the biocompatibility studies reveal that CHIT retains its biocompatible nature after chemical modification. The electrochemical studies conducted onto SH-CHIT/Au electrode reveal that thiol modification in CHIT amino end enhances the electrochemical behavior indicating that it may be attributed to delocalization of electrons in CHIT skeleton that participates in the resonance process. The carboxyl group modified end of DNA probe has been immobilized onto SH-CHIT/Au electrode using N-ethyl-N′-(3-dimethylaminopropyl)carbodimide (EDC) and N-hydroxysuccinimide (NHS) chemistry for detection of complementary, one-base mismatch and non-complementary sequence using electrochemical and optical studies for Mycobacterium tuberculosis detection. It has been found that DNA-SH-CHIT/Au bioelectrode can specifically detect 0.01 μM of target DNA concentration with sensitivity of 1.69?×?10^?6 A μM^?1.     

Asymmetric synthesis of pedamide using I_2-induced heterocyclization to construct the skeleton

An alternative approach to synthesize pedamide,a key building block of pederin was described.Iodine-induced asymmetric heterocyclization was used as the key step to construct the skeleton,a tetrahydropyran ring with three chiral centers.Brown's asymmetric allylation and Lewis acid-mediated allylation were investigated to introduce chains and chiral alcohols.Sharpless dihydroxylation decorated the side chain.And high optically pure target was obtained by removing the epimers formed in these reactions on c...     

Microwave-assisted one-pot synthesis of 3-substituted-3,4-dihydrocoumarins via tendem Konevenagel and Hantzsch reactions

A convenient route for the synthesis of 3,4-dihydrocoumarin derivates from salicylaldehyde derivates and 1,3-dicarbonyl compounds under solvent-free microwave irradiation conditions was described. In this way, a range of compounds was obtained in moderate to good yields in a short reaction time.     

Polyaniline/Single‐Walled Carbon Nanotubes Composite Based Triglyceride Biosensor

Nanocomposite film comprising of polyaniline (PANI) and single walled carbon nanotubes (SWCNT) has been fabricated onto indium‐tin‐oxide (ITO) coated glass plate using electrophoretic technique. Co‐immobilization of glycerol dehydrogenase (GDH) and lipase (LIP) has been done via N‐ethyl‐N′‐(3‐dimethylaminopropyl) carbodiimide and N‐hydroxysuccinimide chemistry to explore its application for triglyceride (tributyrin) sensing. Response studies have been done using linear sweep voltammetry revealing that LIP‐GDH/PANI‐SWCNT‐TB/ITO bioelectrode can detect tributyrin in the range of 50 to 400 mg dL^?1 with low Michaelis–Menten constant of 1.138 mM, improved response time of 12 s, high sensitivity as 4.28×10^?4 mA mg^?1 dL and storage stability of about 13 weeks.     

Synthesis of copper sulphide and copper nanoparticles with microemulsion method

The present work is focused on the synthesis of nanocopper and nanocopper sulphide metallic particles. The precise control of size and shape is best achievable with microemulsion technique, with in situ synthesis in microemulsion. The effect of most crucial operating parameter, water-to-surfactant molar ratio (w), on the product specification including size as well as size distribution and morphology were investigated. The variation of size was observed with variation in w for copper sulphide and copper. Product specifications were analyzed using transmission electron microscope imaging, dynamic light scattering with particle size analyzer and absorption spectra using UV-visible spectrophotometer. It was observed that bigger particles were achieved at higher water-to-surfactant ratio. From systematic study of effect of w on the size and size distribution of copper nanoparticles, the optimum value was chosen for preparation of in situ catalyst. As copper on alumina catalyst has wide catalytic applications of commercial importance, alumina was selected as support. A novel deposition method is developed successfully to deposit the copper nanoparticles from microemulsion on the support. Thus prepared catalyst was analyzed with UV-visible spectrophotometer and found to contain characteristic peak of copper at 655 nm, indicating proper copper deposition on support. XRD analysis of copper on alumina catalyst confirmed presence of metallic copper.     

Electrophoretically deposited polyaniline nanotubes based film for cholesterol detection

Polyaniline nanotube (PANI-NT) based films have been fabricated onto indium-tin-oxide (ITO) coated glass plates via electrophoretic technique. These PANI-NT/ITO electrodes have been utilized for covalent immobilization of cholesterol oxidase (ChOx) using glutaraldehyde (Glu) as cross-linker. Structural, morphological and electrochemical characterization of PANI-NT/ITO electrode and ChOx/Glu/PANI-NT/ITO bioelectrode have been done using FT-IR spectroscopy, SEM, electrochemical impedance spectroscopy and cyclic voltammetry techniques. Response studies of the ChOx/Glu/PANI-NT/ITO bioelectrode have been carried out using both linear sweep voltammetry and UV-Visible spectrophotometry. The results of the biosensing studies reveal that this bioelectrode can be used to detect cholesterol in wide detection range of 25-500 mg/dL with high sensitivity of 3.36 mA mg(-1) dL and fast response time of 30 s at pH 7.4. This bioelectrode exhibits very low value of Michaelis-Menten constant of 1.18 mM indicating enhanced interactions between cholesterol and ChOx immobilized onto this nanostructured PANI matrix.