Papers by Keyword: Nanocrystal

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Authors: E. Nxusani, P.M. Ndangili, R.A. Olowu, A. N. Jijana, T. Waryo, N. Jahed, R.F. Ajayi, Priscilla Gloria Lorraine Baker, Emmanuel Iheanyechukwu Iwuoha
Abstract: Water soluble and biocompatible 3-mercaptopropionic acid capped gallium selenide nanocrystals, were synthesized from hydrated gallium (III) perchlorate and selenide ions. The 3-mercaptopropionic acid capped gallium selenide nanocrystals, was non-fluorescent but showed a sharp UV-vis absorption maximum at 250 nm.The synthesized nanoparticle was used to develop an electrochemical biosensor for the detection of 17-alpha-ethinyl estradiol, an estrogenic endocrine disrupting compound (e-EDC). The biosensor was fabricated by potentiostatic deposition of novel gallium selenide nanocrystals on a L-cystine modified gold electrode, followed by covalent coupling of genetically engineered cytochrome P450-3A4 (CYP3A4), a Heme containing enzyme. The biosensor gave an electrochemical response at about-220 mV. The results revealed that 3-Mecarptopropanoic acid capped Gallium Selenide nanocrystals can be used in conjunction with CYP3A4 as an electrode modifier for the detection of 17-alpha ethinyl estradiol. The 3-Mecarptopropanoic acid capped Gallium Selenide nanoparticles exhibited a semiconductor like behaviour.
Authors: Sachin Tyagi, Ramesh Chandra Agarwala, Vijaya Agarwala
Abstract: Nanocrystalline strontium hexaferrite (SrFe12O19) and barium hexaferrite (BaFe12O19) powders were synthesized by co-precipitation method. The ‘as synthesized’ powders were heat treated (HT) at different temperatures ranging from 800 to 1200°C at a heating rate of 30°C /min in nitrogen atmosphere. Decomposition behaviour and the phases associated therein are investigated by thermal analysis (DTA/DTG/TG) and X-ray diffraction (XRD). Formations of ultrafine particles have been confirmed through field emission scanning electron microscop (FESEM). The superparamagnetic behavior of both, barium and strontium hexaferrite is confirmed by vibrating sample magnetometer (VSM). The increase in saturation magnetization from 1.94 to 31.05 emu/gm in case of barium hexaferrite and from 2.44 to 43.38 emu/gm for strontium hexaferrite is observed with HT temperatures. The changes in coercivity and remanence with HT temperatures for both the ferrites are analysed.
Authors: Stefano Enzo, G. Mulas, Francesco Delogu, R. Frattini
Authors: L.F. Santos, H.C. Vasconcelos, M.I. Barros Marques, Rui M. Almeida
Authors: Toru Tonegawa, Toshiyuki Ikoma, Tomohiko Yoshioka, Kazuo Shinozaki, Nobutaka Hanagata, M. Tanaka
Abstract: Insulin delivery carriers using low crystalline porous zinc hydroxyapatite (ZnHAp) microparticles with different crystal sizes and novel formulation method of poly (lactic acid) (PLA) have been developed to achieve the sustained-release of insulin. The adsorption isotherm curves of insulin dissolved into acetic acid of pH4.5 onto ZnHAp nanocrystals show non-Langmuir type due to the dissolution of the ZnHAp microparticles; the adsorption amounts were increased with the increase of crystalline sizes. The PLA formulation, coating the outer layer of microparticles, showed the apparent reduction of initial burst for insulin. The amounts of initial release of insulin decreased with the increase of crystalline sizes of ZnHAp, which could be attributed to the different meso-porous structure depending on its crystal sizes.
Authors: Jian Yu Huang, Yuntian T. Zhu
Authors: Cai Yan Tan, Qiong Zhi Gan, Jun Fa Xue, Jian Ming Ouyang
Abstract: The aggregation of urine crystallites with different sizes in the urines of 5 cases of uric acid (UA) calculi patients and 5 cases of healthy controls were comparatively investigated by means of nanoparticle size analyzer. Different sizes of urine crystallites were obtained by filtrating the urine through microporous membrane with different pore sizes (0.22, 0.45, 1.2, 3, and 8 μm), respectively. The average particle size () increased rapidly with placement time (t) in the lithogenic patients. The values of the urine crystallites of the controls increased more slowly with t. When t was increased, the autocorrelation curves in the two types of urine crystallites became less smooth and the decay of the correlation curve became slower, and decay time of different sizes of urine crystallites both for the calculi patients and the controls increased. These results indicated that the urine crystallites of the controls were more stable than those of the patients. The rapid aggregation of urine crystallites may be an important factor affecting the growth of crystallites in UA stone patients.
Authors: Daisuke Okai, Kentaro Mori, Gaku Motoyama, Hisamichi Kimura, Hidemi Kato
Abstract: The amorphousization of Zr65Nb35 alloy was performed. The Zr-Nb based alloys contained Al and Co elements were fabricated by arc-melting and melt-spinning methods. The superconducting property of the Zr(65-x)Nb35-xAlx (x = 0~15 at%) and Zr(65-x)Nb20Al15Cox alloys (x = 3~10 at%) was investigated by magnetic susceptibility measurements. The Zr(65-x)Nb20Al15Cox metallic glasses (x = 6~10 at%) with superconducting nanocrystalline particles dispersed in an amorphous matrix exhibited a superconductivity below about 3.5 K. The addition of Co element led drastically to the amorphousization of the superconducting Zr65Nb20Al15 alloy.
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