Study on oxidation layer of size controlled Nickel nanoparticles

Documento submetido para revisão pelos pares. A publicar em Nanoscale Research Letters. ISSN 1556-276XResearch on morphology and structure of oxidation layer of Ni nanoparticles (NPs) is reported. Ni NPs were obtained by wet chemical solution method and their size controlled in the nickel nucleation step using a non-ionic surfactant. Particles were about 50nm in size and polycrystalline. Combining high-angle annular dark field (HAADF) and electron energy loss spectroscopy (EELS), the nickel oxide layer was identified as not continuous and with non homogenous thickness

Hydrothermal assisted synthesis of iron oxide-based magnetic silica spheres and their performance in magnetophoretic water purification

Porous Magnetic Silica (PMS) spheres of about 400 nm diameter were synthesised by one-pot process using the classical Stӧber method combined with hydrothermal treatment. Maghemite nanoparticles (γ-Fe2O3) were used as fillers and cetyltrimethylammonium bromide (CTAB) was used as templating agent. The application of the hydrothermal process (120 °C during 48 h) before the calcination leads to the formation of homogeneous and narrow size distribution PMS spheres. X-ray diffraction patterns (XRD), Infrared measurements (FTIR) and Transmission Electron microscopy (TEM) methods were used to determine the composition and morphology of the obtained PMS spheres. The results show a homogeneous distribution of the γ-Fe2O3 nanoparticles in the silica matrix with a “hollow-like” morphology. Magnetophoresis measurements at 60 T m−1 show a total separation time of the PMS spheres suspension of about 16 min. By using this synthesis method, the limitation of the formation of silica spheres without incorporation of magnetic nanoparticles is overcome. These achievements make this procedure interesting for industrial up scaling. The obtained PMS spheres were evaluated as adsorbents for Ni2+ in aqueous solution. Their adsorption capacity was compared with the adsorption capacity of magnetic silica spheres obtained without hydrothermal treatment before calcination process. PMS spheres show an increase of the adsorption capacity of about 15% of the initial dissolution of Ni2+ without the need to functionalize the silica surface.Fundação para a Ciência e a Tecnologia (FCT

on the use of copper based substrates for ybco coated conductors

It is well known that the recrystallization texture of heavily cold-rolled pure copper is almost completely cubic. However, one of the main drawbacks concerning the use of pure copper cube-textured substrates for YBCO coated conductor is the reduced secondary recrystallization temperature. The onset of secondary recrystallization (i.e., the occurrence of abnormal grains with unpredictable orientation) in pure copper substrate was observed within the typical temperature range required for buffer layer and YBCO processing (600–850 °C). To avoid the formation of abnormal grains the effect of both grain size adjustment (GSA) and recrystallization annealing was analyzed. The combined use of a small initial grain size and a recrystallization two-step annealing (TSA) drastically reduced the presence of abnormal grains in pure copper tapes. Another way to overcome the limitation imposed by the formation of abnormal grains is to deposit a buffer layer at temperatures where secondary recrystallization does not occur. For example, La2Zr2O7 (LZO) film with a high degree of epitaxy was grown by metal-organic decomposition (MOD) at 1000 °C on pure copper substrate. In several samples the substrate underwent secondary recrystallization. Our experiments indicate that the motion of grain boundaries occurring during secondary recrystallization process does not affect the quality of LZO film

Epitaxial growth of SrTiO3 films on cube-textured Cu-clad substrates by PLD at low temperature under reducing atmosphere

The growth of epitaxial {001} SrTiO (STO) on low-cost cube-textured Cu-based clad substrate at low temperature was carried out by means of pulsed laser deposition (PLD). STO film was deposited in one step under a reducing atmosphere (5% H and 95% Ar mixture) to prevent the oxidation of the metal surface. The optimization of PLD parameters leads to a sharpest biaxial texture at a temperature as low as 500 °C and a thickness of 500 nm with a (100) STO layer. The upper limit of highly textured STO thickness was also investigated. The maximum thickness which retains the best quality {001} texture is 800 nm, since the texture is preserved not only through the layer but also on the surface. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurements showed that STO films are continuous, dense, and smooth with very low roughness (between 5 and 7 nm). This paper describes the development of STO layer by means of PLD in absence of oxygen throughout the process, suggesting an alternative and effective method for growing highly {001} textured STO layer on low-cost metal substrates.The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 280432 and by the Spanish Government project MAT2011-29269-C03-03.Peer Reviewe

Design and characterization of Ni2+ and Co2+ decorated Porous Magnetic Silica spheres synthesized by hydrothermal-assisted modified-Stober method for His-tagged proteins separation

The complete elimination of enzymes from the reaction mixture and the possibility of its recycling for several rounds results in great benefits, allowing the reduction of the enzyme consumption and their usability in continuous processes. In this work it is evaluated the capture of a H6-Tagged GFP (GFP-H6) protein on porous magnetic spheres using the Co2+ and Ni2+ affinity adsorption as a cost effective and up scaled alternative way for the immobilization of his-tagged protein. For this propose, Porous Magnetic Silica (PMS) spheres were synthesised by one step hydrothermal assisted modified-Stöber method. The obtained spheres show a homogeneous size distribution of 400 nm diameter. The -Fe2O3 nanoparticles are homogeneously distributed in the silica matrix. The obtained PMS spheres have a saturation magnetization of about 10 emu/g and a a total separation time of 16 min at 60 T/m was measured by magnetophoresis. The obtained PMS spheres were successfully and homogeneously decorated with Co2+ and Ni2+ and then evaluated for the capture of a GFP-H6 protein. The results were compared with the performance of the commercial beads Dynabeads® His-Tag Isolation & Pulldown.This work is funded by FEDER funds through the "programa Operacional Factores de Competitividade - COMPETE" and by national funds by FCT- Fundacao para a Ciencia e a Tecnologia, project references PEst-C/FIS/U10607/2011, PTDC/CTM/69316/ 2006, and NANO/NMed-SD/0156/2007. The authors also thank support from the COST Action MP1003, 2010 'European Scientific Network for Artificial Muscles'. M.B. thanks the FCT for support under the "Compromisso corn a Ciencia" program. We would like to thank the Protein Production Platform (CIBER-BBN) for helpful technical assistance and for protein production and purification services (http://bbn.ciber-bbn.es/programas/plataformas/equipamiento). The authors appreciate the financial support through the grant IPT-010000-2010-6 (MICINN, INNPACTO subprogram). We also acknowledge the support of the CIBER de Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), an initiative funded by the VI National R&D&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund

Improving the binding capacity of Ni2+ decorated porous magnetic silica spheres for histidine-rich protein separation

The complete elimination of enzymes from the reaction mixture and the possibility of its recycling for several rounds results in great benefits, allowing the reduction of the enzyme consumption and their usability in continuous processes. In this work it is evaluated the capture of a H6-Tagged GFP (GFP-H6) protein on porous magnetic spheres using the Co2+ and Ni 2+ affinity adsorption as a cost effective and up scaled alternative way for the immobilization of his-tagged protein. For this propose, Porous Magnetic Silica (PMS) spheres were synthesised by one step hydrothermal assisted modified-Stöber method. The obtained spheres show a homogeneous size distribution of 400 nm diameter. The y-Fe2O3 nanoparticles are homogeneously distributed in the silica matrix. The obtained PMS spheres have a saturation magnetization of about 10 emu/g and a a total separation time of 16 min at 60 T/m was measured by magnetophoresis. The obtained PMS spheres were successfully and homogeneously decorated with Co2+ and Ni 2+ and then evaluated for the capture of a GFP-H6 protein. The results were compared with the performance of the commercial beads Dynabeads® His-Tag Isolation & Pulldown.This work is funded by FEDER funds through the “programa Operacional Factores de Competitividade – COMPETE" and by national funds by FCT- Fundação para a Ciência e a Tecnologia, project references PEst-C/FIS/UI0607/2011, PTDC/CTM/69316/2006, and NANO/NMed-SD/0156/2007. The authors also thank support from the COST Action MP1003, 2010 ‘European Scientific Network for Artificial Muscles’. M.B. thanks the FCT for support under the “Compromisso com a Ciência” program. We would like to thank the Protein Production Platform (CIBER-BBN) for helpful technical assistance and for protein production and purification services (http://bbn.ciber-bbn.es/programas/plataformas/equipamiento). The authors appreciate the financial support through the grant IPT-010000-2010-6 (MICINN, INNPACTO subprogram). We also acknowledge the support of the CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER- BBN), an initiative funded by the VI National R&D&i Plan 2008-2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund

Characterization of Facultative Thermophilic Microbial Community of Composts by ARDRA

細菌的活性是堆肥成熟?及品質的重要決定因素之一。為?瞭解本土堆肥在堆肥化過程中細菌的活性，我們分析?臺?虎尾廠堆肥中兼氧性嗜熱細菌的族群。總共分??412 個菌?，依據擴增核?體DNA 限制片段分析（ARDAR）並輔以傳統的菌?觀察，格?氏染色，及生化測驗，可將他們分成24 群。整體而言，ARDAR 與傳統方法的結果相當一致，均顯示24 群中之第17 群有別於其它的菌群。根據擴增的核?體DNA 序?及親緣樹的分析，證明第17 群為親緣上接近Pseudomonas stutzer 的?膿桿菌屬，其餘的23 菌群屬於枯草桿菌，在親緣上接近Bacillcus licheniformis 及Bacillus sonorensis。這些研究結果將有助於台灣區域性之堆肥研究。本研究同時證明ARDAR 可直接用於鑑定堆肥中的菌種。Bacterial activity is one of the factors to determine the maturity and quality of the composts. In order to have a better understanding of the composition of bacteria involving in the composting processes, the facultative thermophilic bacrerial community of local composts was analyzed. A total of 412 colonies were isolated and analyzed by amplified rDNA restriction analysis (ARDRA) and traditional colony observation, staining and biochemical tests. The isolates were divided into 24 groups mainly by ARDRA. Among these groups, the largest one contained 137 isolates. Mostly, the ARDRA analysis was in good conformity with the analysis of traditional methods: both results indicated that group 17 was a distinct one. The phylogenetic tree constructed based on the 16S rDNA sequence analysis demonstrated that the bacterial community of composts analyzed in this study was dominated by Bacillus spp., closely related to Bacillus licheniformis and Bacillus sonorensis. Only 16 isolates in group 17 were Pseudomonas spp., closely related to Pseudomonas stutze

Optimisation of surface treatments of TiO2:Nb transparent conductive coatings by a post-hot-wire annealing in a reducing H2 atmosphere

Transparent and electrically conductive niobium-doped TiO2 thin films have been deposited on glass surfaces by d.c.-pulsed reactive magnetron sputtering from a composite Ti:Nb target, using oxygen as reactive gas. A rapid 1 min annealing at 500 °C in an atomic hydrogen rich atmosphere, obtained by flowing H2 on a Ta filament resistively heated to 1750 °C in vacuum (hot-wire), proved to be very efficient in enhancing the electrical properties of these ~100 nmthick TiO2:Nb thin films. Dark conductivity (σd) and its activation energyweremeasured as a function of (inverse) temperature and the value of σd at room temperature was used to assess the effect of the H2 annealing on the transport properties. A 5-order ofmagnitude increase in electrical conductivitywas observed for optimised treatment conditions at a hydrogen pressure of 10 Pa. A maximum value of σd in the range of ~1.4 × 103 S/cm was attained for optimised conditions, where a level of ~6 at.% of H doping was measured close to the film surface. X-ray photoelectron spectroscopy, elastic recoil detection analysis, Rutherford backscattering and Raman spectroscopies were used to access information of composition and film structure for the explanation of the strong enhancement of the film's electrical conductivity and band-gap widening to 3.45 eV following hot-wire treatments. These thin films can be used as transparent conductive oxide contact layers for photovoltaic applications.The authors acknowledge the funding from the Portuguese FCT COMPETE scientific program

Feasible and pure P2O5-CaO nanoglasses: An in-depth NMR study of synthesis for the modulation of the bioactive ion release

The use of bioactive glasses (e.g. silicates, phosphates, borates) has demonstrated to be an effective therapy for the restoration of bone fractures, wound healing and vascularization. Their partial dissolution towards the surrounding tissue has shown to trigger positive bioactive responses, without the necessity of using growth factors or cell therapy, which reduces money-costs, side effects and increases their translation to the clinics. However, bioactive glasses often need from stabilizers (e.g. SiO44-, Ti4+, Co2+, etc.) that are not highly abundant in the body and which metabolization is not fully understood. In this study, we were focused on synthesizing pure calcium phosphate glasses without the presence of such stabilizers. We combined a mixture of ethylphosphate and calcium 2-methoxyethoxide to synthesize nanoparticles with different compositions and degradability. Synthesis was followed by an in-depth nuclear magnetic resonance characterization, complemented with other techniques that helped us to correlate the chemical structure of the glasses with their physiochemical properties and reaction mechanism. After synthesis, the organically modified xerogel (i.e. calcium monoethylphosphate) was treated at 200 or 350¿°C and its solubility was maintained and controlled due to the elimination of organics, increase of phosphate-calcium interactions and phosphate polycondensation. To the best of our knowledge, we are reporting the first sol-gel synthesis of binary (P2O5-CaO) calcium phosphate glass nanoparticles in terms of continuous polycondensated phosphate chains structure without the addition of extra ions. The main goal is to straightforward the synthesis, to get a safer metabolization and to modulate the bioactive ion release. Additionally, we shed light on the chemical structure, reaction mechanism and properties of calcium phosphate glasses with high calcium contents, which nowadays are poorly understood. Statement of Significance The use of bioactive inorganic materials (i.e. bioactive ceramics, glass-ceramics and glasses) for biomedical applications is attractive due to their good integration with the host tissue without the necessity of adding exogenous cells or growth factors. In particular, degradable calcium phosphate glasses are completely resorbable, avoiding the retention in the body of the highly stable silica network of silicate glasses, and inducing a more controllable degradability than bioactive ceramics. However, most calcium phosphate glasses include the presence of stabilizers (e.g. Ti4+, Na+, Co2+), which metabolization is not fully understood and complicates their synthesis. The development of binary calcium phosphate glasses with controlled degradability reduces these limitations, offering a simple and completely metabolizable material with higher transfer to the clinicsPeer Reviewe