Immobilisation of antibody on microporous silicon membranes

Microchimica Acta - The immobilisation of antibody on silicon membranes containing arrays of micropores was studied. The membranes are modified by the deposition of aminopropyl triethoxysilane to...     

A novel alkenyl-substituted ansa-zirconocene complex with dual application as olefin polymerization catalyst and anticancer drug

The alkenyl substituted fulvene compound, (C₅H₄)CMe(CH₂CH₂CHCMe₂) (1), reacts with one equivalent of LiMe to give the lithium derivative Li{C₅H₄(CMe₂CH₂CH₂CHCMe₂)} (2). The reaction of 2 with Me₂Si(C₅Me₄H)Cl gave the ansa-ligand precursor Me₂Si(C₅Me₄H)(C₅H₄(CMe₂CH₂CH₂CHCMe₂)) (3), which after the subsequent reaction with 2 equivalents of LiBuⁿ yielded the dilithium salt Li₂{Me₂Si(C₅Me₄)(C₅H₃(CMe₂CH₂CH₂CHCMe₂))} (4). The alkenyl-substituted zirconocene complex [Zr{Me₂Si(η⁵-C₅Me₄)(η⁵-C₅H₃(CMe₂CH₂CH₂CHCMe₂))}Cl₂] (5) was synthesized by the equimolar reaction of 4 and ZrCl₄. 5 was characterized by spectroscopic methods and by single crystal X-ray diffraction studies. The zirconocene compound 5 has been tested as a catalyst in the polymerization of ethylene at different temperatures and Al:Zr ratios, and also in the co-polymerization of ethylene and 1-octene, observing modest co-monomer incorporations. In addition, the cytotoxic activity of 5 was tested against tumour cell lines 8505C anaplastic thyroid cancer, A253 head and neck tumour, A549 lung carcinoma, A2780 ovarian cancer and DLD-1 colon carcinoma. Complex 5 showed the best cytotoxic activity on A2780 ovarian cancer (IC₅₀ value of 36.8 ± 5.9 μM). This represents the highest reported cytotoxic activity of a zirconocene complex on A2780 ovarian cancer. In addition, the cytotoxic activities of 5, have been compared with those obtained using cisplatin.     

Effect of thermal expansion mismatch in grating material and host specimen on thermal sensitivity of FBG sensor

Authors have studied thermal sensitivity characteristics of FBG temperature sensor attached to the surface of targeted host specimen (Lee and Lee in J Korean Phys Soc 59(5):3188–3191, 2011; Yu-Lung and Han-Sheng in Meas Sci Technol 9:1543–1547, 1998; Reddy et al. in Opt Appl 40(3):685–692, 2010). In their mathematical analysis, the coefficient of thermal expansion of grating material is ignored due to its contribution to the shift in the wavelength is small as compared to shift because of CTE of host specimen. However, we find that the Bragg’s wavelength shift used for measuring temperature in FBG sensor is dependent on difference in thermal expansions of grating and targeted host specimen materials. We have investigated the effect of the expansion in the material of the grating as well as that of host material and have found that at low temperature the difference in the shift in wavelength is indeed very small of the order of 0.67 pm at \(26\,{^\circ }\hbox {C}\), but the difference in the shift in the wavelength at higher temperature say 350–\(400\,{^\circ }\hbox {C}\) is quite large of the order of 250 pm and cannot be neglected as it will result in error reading of the temperature for higher ranges.     

A domino approach of Heck coupling for the synthesis of β-trifluoromethylstyrenes

A domino approach of Heck coupling was used to synthesize β-trifluoromethylstyrene derivatives from iodoarenes and 1-iodo-3,3,3-trifluoropropane in moderate to good yields. This method avoids the use of low-boiling, gaseous reagents such as 3,3,3-trifluoropropene, and additives and phosphines in the catalytic system.     

Poly(vinylidene fluoride)/clay nanocomposites prepared by melt intercalation: Crystallization and dynamic mechanical behavior studies

The preparation and properties of poly(vinylidene fluoride) (PVDF)/clay nanocomposites are reported for the first time. PVDF/clay nanocomposites were prepared by melt intercalation with organophilic clay. The composites were characterized with X‐ray diffraction, differential scanning calorimetry, and dynamic mechanical analysis. X‐ray diffraction results indicated intercalation of the polymer into the interlayer spacing. PVDF in the nanocomposites crystallized in the β form. Differential scanning calorimetry nonisothermal curves showed an increase in the melting and crystallization temperatures along with a decrease in crystallinity, as evidenced by the melting and crystallization peaks. Isothermal crystallization studies showed an enhanced rate of crystallization with the addition of clay, as evidenced by a reduction in the crystallization time. Dynamic mechanical analysis indicated significant improvements in the storage modulus over a temperature range of ?100 to 150 °C. The tan δ peak signifying the glass‐transition temperature of PVDF shifted to higher temperatures. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 1682–1689, 2002     

Stereochemical effects of chiral monolayers on enhancing the resistance to mammalian cell adhesion

This work describes the different durations of surface confinement of adhered mammalian cells by monolayers comprised of enantiomers of bio-inert polyol-terminated alkanethiols. Enhanced resistance to protein adsorption and cell adhesion is obtained on monolayers formed by a racemic mixture of the enantiomeric alkanethiols.     

Water-driven ligations using cyclic amino squarates: a class of useful SN1-like reactions

We report a class of water-soluble and -stable cyclic amino squarates that ligate with cysteine or lysine residues without side-products in an entirely aqueous environment. The ligations include addition-elimination reactions that are promoted by water in a way similar to S(N)1 reactions. The structural versatility of the reactants allows the potential recognition of selected amino acid residues on proteins.     

The Equations of Equilibrium in Orthogonal Curvilinear Reference Coordinates

Analytical solutions to problems in finite elasticity are most often derived using the semi-inverse approach along with the spatial form of the equations of motion involving the Cauchy stress tensor. This procedure is somewhat indirect since the spatial equations involve derivatives with respect to spatial coordinates while the unknown functions are in terms of material coordinates, thus necessitating the use of the chain rule. In this classroom note, we derive compact expressions for the components of the divergence, with respect to orthogonal material coordinates, of the first Piola-Kirchhoff stress tensor. The spatial coordinate system is also assumed to be an orthogonal curvilinear one, although, not necessarily of the same type as the material coordinate system. We show by means of some example applications how analytical solutions can be derived more directly using the derived results.     

Performance Evaluation of the Optimized Error Correction Based Hop Localization Approach in a Wireless Sensor Network

Wireless Personal Communications - Nature inspired computing has become one of the necessities of real time application-based methods. While considering the localization aspects of the wireless...     

Potential Associations among Bioactive Molecules,Antioxidant Activity and Resveratrol Production in Vitis vinifera Fruits of North America

Grapes (Vitis vinifera L.) are rich in bioactive molecules contributing to health benefits. Consumption of grapes is linked to reduced incidence of cardiovascular diseases. Studies on table grape cultivars are limited although much attention in research was focused on the wine industry. Bioactive effects of grapes as anti-inflammatory, anticarcinogenic, cardioprotective, vasorelaxant, phytoestrogenic and neuroprotective have also been reported. For example, resveratrol is a natural food ingredient present in grapes, with high antioxidant potential. Here we conducted an exploratory study to investigate bioactive molecules, antioxidant activity and the association between constitutive stilbene synthase (STS) gene expression and the resveratrol biosynthesis in selected table grape varieties in North America. The phenolic compounds, fatty acid composition and antioxidant activity of four grape varieties were compared. Red Globe variety was rich in unsaturated fatty acids as well as phenolic compounds such as caffeic acid, quercetin and resveratrol. Meanwhile, the constitutive expression of grape stilbene synthase gene was higher in Flame and Autumn Royal where resveratrol content of these cultivars was relatively low compared to the Red Globe variety. This study shows the potential links in grape antioxidant activity and resveratrol production, but more studies are necessary to show the association.