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Curing Study of the New Silane Monomers and Their IPNs
Firas Jameel Jabbar 한국고분자학회 2021 폴리머 Vol.45 No.6
Interpenetrating polymer networks (IPNs) that have silane resins as one of their components are industrially important due to their physical and chemical properties. The current study included preparation and characterization of two types of unsaturated silane monomers in order to prepare new types of IPNs with unsaturated polyesters (palatal). These monomers were characterized with Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (<SUP>1</SUP>H NMR), and their molecular weights were determined by cryoscopy technique. The curing properties of the silane monomers and the IPNs were observed by differential scanning calorimetry (DSC), and several of thermal curing functions were determined, such as the initial curing temperature, optimum curing temperature, curing energy, activation energy and rate of curing. There was a significant decrease in the initial and maximum curing temperatures compared with the unsaturated polyester resin (palatal) due to the decrease in the activation energy from 105.4 to 77.3 ºC when the allyoxy silane monomer percentage was shifted from 5 to 20%. Meanwhile, the activation energy for the IPNs based on α-methyl-butenoxy silane decreased from 96.8 to 55.8 kJ/mol.
Honokiol exerts dual effects on browning and apoptosis of adipocytes
Lone, Jameel,Yun, Jong Won INSTITUTE OF PHARMCOLOGY POLISH ACADEMY OF SCIENCE 2017 PHARMACOLOGICAL REPORTS Vol.69 No.6
<P>Conclusion: Our findings suggest that honokiol exhibits a modulatory role in adipocytes via induction of browning and apoptosis in white adipocytes, promotion of catabolic lipid metabolism, as well as activation and inhibition of apoptosis in HIB1B brown adipocytes, thereby exhibiting therapeutic potential against obesity. (c) 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Sp. z o.o. All rights reserved.</P>
Umsa Jameel,Mingqiao Zhu,Xin-Zhi Chen,Hengquan Chen,Nousheen Iqbal,Zhangfa Tong,Satmon John Timayo 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.6
Selective oxidation of olefins using molecular oxygen is a great challenge. This study reports two types of novel eco-friendly heterogeneous hybrid catalysts. One comprises of a lacunary Keggin-type polyoxometalate (POM) GaW11 linked to nano-sized silica using (3-aminopropyl) triethoxysilane (APTES) to form GaW11-APTES@SiO2 . Another catalyst is Au/GaW11-APTES@SiO2 prepared by wet deposition of nano-gold on the former one. The catalysts were characterized and used for the solvent-free oxidation of cyclohexene with molecular oxygen under mild reaction conditions. Both the catalysts showed good conversion and significant selectivity towards oxidized products for cyclohexene. GaW11-APTES@SiO2 showed a high conversion of up to 62.02% with a selectivity of 59.13% towards epoxide at a mild temperature of 50°C. Au/GaW11-APTES@SiO2 showed a conversion of 69.32% with 57.34% selectivity to 2-cyclohexene-1-ol at a temperature of 80°C. The heterogeneous catalysts were reused several times with no significant loss in conversion or selectivity towards the oxidized products.
Mohammed Jameel Hefne,Waleed Asiri,Syed Rashid Habib 대한치과보철학회 2014 The Journal of Advanced Prosthodontics Vol.6 No.6
PURPOSE To compare the accuracy of marginal and internal adaptation of zirconia (Zr) copings fabricated on anatomic (A), semi-anatomic (SA) and non-anatomic (NA) occlusal surface preparations. MATERIALS AND METHODS 45 extracted bicuspid teeth were prepared for receiving zirconia crowns, with different occlusal preparation designs A=15, SA=15 & NA=15. The Zr copings were fabricated by using CAD4DENT, CAD/CAM. The copings were adjusted, cemented and were cross sectioned centrally from buccal cusp tip to lingual cusp tip into mesial and distal halves. The copings were examined under electron microscope at ×200 magnification and the measurements were recorded at 9 predetermined areas in micrometers. RESULTS Overall mean gap values for the three groups was found to be 155.93±33.98 µm with Anatomical Occlusal preparation design having the least gap value of 139.23±30.85 µm showing the best adaptation among the groups. Post Hoc Tukey's test showed a statistically significant difference (P=.007) between the means of gap for A & NA preparation designs. Measurements recorded at 9 predetermined points showed variations for the three groups. CONCLUSION Anatomical occlusal preparation designs resulted in better marginal and internal adaptation of Zr copings. There is a considerable variation between the measured marginal and internal gap values for the Zr copings fabricated by the (CAD4DENT-CAD/CAM). This variation may be associated with the lack of standardization of the preparation of teeth, computerized designing of the coping for each tooth, cement used, uniform pressure application during the cementation of the copings, sectioning of the copings and the microscopic measurements.