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Supplemental material, sj-docx-1-aph-10.1177_10105395231166544 for Household Food Insecurity Negatively Impacts Diet Diversity in the Vietnamese Mekong Delta: A Cross-Sectional Study by Thuy Ngoc Vuong, Chinh Van Dang, Paul Jagals, Simon Toze, Danielle Gallegos and Michelle Gatton in Asia Pacific Journal of Public Health

Supplemental material, sj-docx-2-aph-10.1177_10105395231166544 for Household Food Insecurity Negatively Impacts Diet Diversity in the Vietnamese Mekong Delta: A Cross-Sectional Study by Thuy Ngoc Vuong, Chinh Van Dang, Paul Jagals, Simon Toze, Danielle Gallegos and Michelle Gatton in Asia Pacific Journal of Public Health

Supplemental material, sj-docx-2-aph-10.1177_10105395231166544 for Household Food Insecurity Negatively Impacts Diet Diversity in the Vietnamese Mekong Delta: A Cross-Sectional Study by Thuy Ngoc Vuong, Chinh Van Dang, Paul Jagals, Simon Toze, Danielle Gallegos and Michelle Gatton in Asia Pacific Journal of Public Health

For the first time, the BaTiO3 nano-sized particles were obtained through solid-state reaction by employing the titanium oxide nanoparticle. Meanwhile, by using TiO2 with micro-sized particles, the synthesized BaTiO3 shows the micro-sized. The XRD pattern confirms that both BaTiO3 nano-sized and micro-sized particles display the tetragonal structure. Both SEM and TEM analysis revealed that the size of the nano-sized material is in the range of 30–50 nm; in the meantime, the microsized material shows a size of 500 nm. The Eg of both BaTiO3 micro-sized and nano-sized were calculated by using the Kubelka-Munk function. The shifted bandgap of BaTiO3 nano-sized particle is nearly 0.24 eV larger than that of BaTiO3 miro-sized particle due to the particle size effect. The P-E measurement of n-BaTiO3 proved that the obtained BaTiO3 nano-sized is ferroelectric material. The result may provide a new route for the fabrication of barium titanate nanoparticle with ferroelectric properties.

In this work, a highly efficient adsorbent consisting of the ZnO/Graphene composite was prepared for the first time via the sonification route using urea as an alkaline precursor. The synthesized ZnO/Graphene composite provides the highest specific surface area comparing to other ZnO/Graphene composites synthesized by different approaches presented in the literature. For all we know, this is the first time the obtained ZnO/Graphene composite was used as an adsorbent for the transformer oil purification. The results showed that the ZnO/Graphene composite has a higher purification capacity than the conventional adsorbent, a commercial zeolite. Several factors that may underpin this outstanding result, such as the unreduced oxygen functional groups, the vacancy defects on the surface of the RGO flake, the high specific surface area, and the suitable pore size of the ZnO/Graphene composite for oil refining. Besides, the 3D structure of the ZnO/Graphene composite can enlarge the residence purification time of the transformer oil, helping to improve the purification capacity of the ZnO/Graphene composite.

Herein, MnO2@SiO2/C was produced from rice husk derived SiO2/carbon composite and MnO2 via hydrothermal method. The nanostructure gave good microstructural, morphological properties with highly catalytic properties. The hybrid catalyst comprising of MnO2@SiO2/C nanocomposite-supported gold nanoparticles was successfully fabricated by the novel solid grinding and tested for CO oxidation’s application. MnO2 nanoballs are 5 − 8 nm in diameter with a shell thickness of 1 nm, packing with laminar [MnO6] unit cells. The as-prepared gold catalysts containing 2wt% of Au loading, exhibited 50% CO conversion and a high specific activity of 0.21 molCO gAu−1 h−1 at 38 °C. MnO2@SiO2/C nanocomposite-supported gold nanoparticles were prepared by solid grinding using a non-volatile organogold(III) complex and rice husk. The catalysts showed high activity for CO oxidation.

g-C3N4@WO3.H2O nanoplate composite adsorbents were prepared in a simple acid precipitation method at room temperature. The g-C3N4@WO3.H2O nanoplate composite adsorbents were characterized by X-ray powder diffraction, micro-Raman spectroscopy, Fourier transform infrared spectra, scanning electron microscopy and UV-vis diffuse reflectance spectroscopy. The results show that the orthorhombic-phase WO3.H2O nanoplates with dimensions of [Formula: see text][Formula: see text]nm3 were successfully composited with g-C3N4. The methylene blue dye generation activity of these adsorbents was evaluated. The kinetics and absorption model of g-C3N4@WO3.H2O nanoplate composite adsorbents were further studied.

Supported nanomaterials can be used in a wide range of applications such as microelectronics, energy storage, sensors, sorbents, and catalysts due to their outstanding chemical and physical properties. In this work, we contribute a comprehensive review of a new fabrication method, sacrificial template-accelerated hydrolysis (STAH), for the synthesis of some typically supported nanomaterials. The report can be used to clearly understand the fabrication of nanomaterials using STAH method as well as the mechanism of the method, and the applications of the obtained nanomaterials.

For the first time, the BaTiO₃ nano-sized particles were obtained through solid-state reaction by employing the titanium oxide nanoparticle. Meanwhile, by using TiO₂ with micro-sized particles, the synthesized BaTiO₃ shows the micro-sized. The XRD pattern confirms that both BaTiO₃ nano-sized and micro-sized particles display the tetragonal structure. Both SEM and TEM analysis revealed that the size of the nano-sized material is in the range of 30-50 nm; in the meantime, the microsized material shows a size of 500 nm. The Eg of both BaTiO₃ micro-sized and nano-sized were calculated by using the Kubelka-Munk function. The shifted bandgap of BaTiO₃ nano-sized particle is nearly 0.24 eV larger than that of BaTiO₃ miro-sized particle due to the particle size effect. The P-E measurement of n-BaTiO₃ proved that the obtained BaTiO₃ nano-sized is ferroelectric material. The result may provide a new route for the fabrication of barium titanate nanoparticle with ferroelectric properties.

This study synthesized cuprous oxide nanoparticles (Cu2O-ONPs) from the green precursors CuSO4.3H2O and Na2SO3. The materials samples were studied at prepared temperatures of 70 °C, 80 °C, 90 °C and 100 °C. The structure and characteristics of the materials were determined by methods such as Raman shift, UV-vis absorption spectrum, SEM, XRD. The results showed that, Cu2O-ONPs were crystallized the best in octahedral form at temperature of 90 °C. The absorption spectrum of the materials was in the visible light region \(\lambda \,\, \approx\) 500–600 nm with the band gap energy defined as Eg \(\approx\) 1.78–2.1eV. At calcination temperatures of 200 °C the materials retained the octahedral shape, but the absorption spectrum was shifted strongly in visible light region \(\lambda \,\, \approx\) 600–700 nm with Eg \(\approx\) 1.94eV. At the firing temperature of 300–400 °C the octahedral shapes of the materials were slightly distorted. At 500 °C the materials particles were inflated, broken and no longer retaining the original octahedral shape. Within this high temperature range of 300–500 °C the absorption spectra of the materials samples were shifted more strongly in visible light region \(\lambda \,\, \approx\) 800–900 nm, the optical band gap energy was reduced to a value Eg \(\approx\) 1.37–1.46eV which was due to the existence of two Cu2O-CuO phases. These will be desirable of material fabrication for applications in photochemical reactions in visible light region and other specific commercial applications that need further research and exploitation.

In this study, the electrochemical immunosensor for detecting Newcastle disease virus using the chicken egg yolk antibodies (IgY) was developed. The developed immunosensor was built into a three-electrode system consisting of two gold electrodes (a working electrode and a counter electrode) and a quasi-reference Ag/AgCl electrode. The IgY antibodies against Newcastle disease virus were immobilized on the working electrode (immunosensor) and the effect of the antibody concentration and virus incubation time on the output signal of the immunosensors was investigated. The investigation results show that when the antibody concentration was 60 µg/mL and the virus incubation time was 1 hour, the output signal of the immunosensors reached its maximum value (∆Ipeak = 0.1602). The detection limit of the sensors was 102 EID50/mL (EID50: 50% Empryo Infective Dose) at 25 oC. There was a good linear relationship between the ∆Ipeak and the logarithm of the virus Newcastle concentration in the range from 102 to 106 EID50/mL. The linear equation is ∆Ipeak = 0.0280logN – 0.00368 with the correlation coefficient of R2 = 0.9972.

In this paper, we present the results of the study of the effect of residual La on crystal structure, magnetic properties of La1+dFe11.05Si1.95 (d = 0.00; 0.03; 0.06 and 0.09) compounds. The analysis of X-ray diffractions showed that when the La content increases to 9%, the structure still remains cubic in a typical NaZn13 arrangement with unchanged lattice constant (about 0.5%). All compounds exhibit ferromagnetic - paramagnetic phase transitions. The Curie temperature TC increases slightly from 235 to 245 K.

LiMnxFe(1-x)PO4 olivine cathode material (x= 0.1; 0.2; 0.3 and 0.8) fabricated according to hydrothermal route. Micro-Raman spectroscopy, SEM scanning electron microscopy, UV-Vis absorption spectra and reflectance spectra methods were performed to study the characteristics of materials. The results showed that LiMnxFe(1-x)PO4 prepared materials were nano-meter in size (60-100 nm) and distorted sphere-like shape. The material has bands in the Raman spectrum corresponding to the position of the bands of the pure LiFePO4 and shift slightly. The band position at 410 cm-1 (corresponding to the position of the n2 band of the pure LiFePO4 sample) was attenuated of the sample in which Mn2+ ion content replaced Fe2+ ion content to 0.8 molar ratio. But the band position at 1020 cm-1 appeared with Strengthening intensity (corresponding to the position of the n3 band of the pure LiMnPO4 sample). The optical band gap energy of samples determined according to the Tauc equation in the range of 3.33-3.5 eV.

In this study, with the aim of improving the photocatalytic efficiency of TiO2, we studied the synthesis of La3+ doped TiO2 (with doped rates 1%, 2.5%, 5% mol/mol compared to Ti4+) by hydrothermal method. The hydrothermal condition was set at 180 °C for 12 hours. Material characteristics were investigated by XRD, SEM and solid UV-Vis methods. The results show that, all prepared materials have a crystal particle size of about nano-meters, small and smooth (4.5¸6.5 nm). La3+ doped TiO2 samples had a shift towards longer wavelengths (l» 400¸500 nm) compared to non-doped TiO2 sample (l£ 380 nm). The band gap energy (Eg) of La3+ doped TiO2 samples was reduced to 3.04¸3.10 eV . The yield of MB degradation of La3+ doped TiO2 at 5% mol/mol reached the highest ~93% after 60 minutes under ultraviolet irradiation. Keywords Anatase TiO2, photocatalysis, La3+ doped TiO2, hydrothermal method, ultraviolet irradiation. References [1] D. Nassoko, Y. F. Li, H. Wang, J. L. Li, Y. Z. Li, Y. Yu, Nitrogen-doped TiO2 nanoparticles by using EDTA as nitrogen source and soft template: Simple preparation, mesoporous structure, and photocatalytic activity under visible light, Journal of Alloys and Compounds. 540 (2012) 228-235. https://doi.org/10.1016/j.jallcom.2012.06.085.[2] M. Khatamian, S. Hashemian, A. Yavari, M. Saket, Preparation of metal ion (Fe3+ and Ni2+) doped TiO2 nanoparticles supported on ZSM-5 zeolite and investigation of its photocatalytic activity, Materials Science and Engineering B. 177 (2012) 1623-1627. http://dx.doi.org/10.1016/ j.mseb.2012.08.015.[3] X. Zhang, Q. Liu, Visible-light-induced degradation of formaldehyde over titania photocatalyst co-doped with nitrogen and nickel, Applied surface Science. 254(15) (2008) 4780-4785. https://doi.org/10.1016/j.apsusc.2008.01.094.[4] Y. Wang, H. Cheng, L. Zhang, Y. Hao, J. Ma, B. Xu, W. Li, The preparation, characterization, photoelectrochemical and photocatalytic properties of lanthanide metal-ion-doped TiO2 nanoparticles, Journal of Molecular Catalysis A: Chemical. 151 (2000) 205-216. https://doi.org/10. 1016/s 1381-1169(99)00245-9[5] M. Meksi, G. Berhault, C. Guillard, H. Kochkar, Design of TiO2 nanorods and nanotubes doped with lanthanum and comparative kinetic study in the photodegradation of formic acid, Catalysis Communications. 61 (2015) 107-111. https://doi. org/ 10.1016/j.catcom.2014.12.020.[6] Q. Wang, S. Xu, F. Shen, Preparation and characterization of TiO2 photocatalysts co-doped with iron (III) and lanthanum for the degradation of organic pollutants, Applied Surface Science. 257 (2011) 7671-7677. https://doi.org/10.1016/j. apsusc.2011.03.157.[7] L. Elsellami, H. Lachheb, A. Houas, Synthesis, characterization and photocatalytic activity of Li, Cd-, and La-doped TiO2, Materials Science in Semiconductor Processing. 36 (2015) 103-114. https://doi.org/10.1016/j.mssp.2015.03.032.[8] J. Nie, Y. Mo, B. Zheng, H. Yuan, D. Xiao, Electrochemical fabrication of lanthanum-doped TiO2 nanotube array electrode and investigation of its photoelectrochemical capability, Electrochimica Acta. 90 (2013) 589-596. http://dx.doi.org/10. 1016/j.electacta. 2012.12.049.[9] Y. Chen, Q. Wu, C. Zhou, Q. Jin, Enhanced photocatalytic activity of La and N co-doped TiO2/diatomite composite, Powder Technology. 322 (2017) 296-300. http://dx.doi.org/10.1016/ j.powtec.2017.09.026. [10] I. Ganesh, P. P. Kumar, I. Annapoorna, J. M. Sumliner, M. Ramakrishna, N. Y. Hebalkar, G. Padmanabham, G. Sundararajan, Preparation and characterization of Cu-doped TiO2 materials for electrochemical, photoelectrochemical, and photocatalytic applications, Applied Surface Science, 293 (2014) 229-247. http://dx.doi.org/10. 1016/j.apsusc.2013.12.140.

The saturated magnetization in 20% substituted La0.8R0.2(Fe0.88Si0.12)13 (R = Sm, Tb) magneto-caloric alloys is discussed in this work. The measurements were taken up to 70 kOe (7 Tesla) to detect the saturation of magnetic moments. As reported recently [Mat. Trans. 59(7) (2018) 1068], these compounds show a large variation of magnetic entropies at low field variation (~ 1.5 T), which associate with the large relative cooling efficiency (RCP) of 52 (for Tb-doped) and 102 J/kg (for Sm-doped) even at low effective DH of ~ 15 kOe. We re-detected the effective range of field variation DH and recognized that the effective DH ~ 5 kOe which is much lower than the value of other magneto-caloric compounds and is excellent for application of Sm-doped compound in modern cooling devices. Keywords: Magnetic, alloys, LaFe13, phase transition, rare-earth.

Background: Using social media (SM) for educational purposes might improve academic performance. Aim: This paper aims to describe health science students’ use of SM for educational purposes and its association with their academic performance. Methods: Two hundred ninety-seven undergraduate health science students completed a self-administered questionnaire comprising 4 sections related to social media. Results: Almost all students (99.7%) reported using SM for learning, most (90.9%) of them daily. The most preferred type of SM learning was Facebook. Most students thought that using SM for learning is convenient and useful. They suggested there should be 1 Facebook account for each subject, that every classmate could access to obtain knowledge from lecturers and to interact between students and lecturers. The logistic regression model showed that the more time students practiced following the advice on posted information, the more likely they were to achieve a GPA at distinction level or above (OR = 4.2; OR = 5.4, and OR = 9.4, respectively with times of practicing). Conversely, the students who used SM for learning less than once a month were less likely to obtain a GPA at distinction level (OR = 0.5). Conclusions: Almost all health science students used SM to support learning and use of SM for learning was associated with higher academic performance.

This study aimed at finding effective strategies for high-performance removal of reactive blue 19 (RB19) dye from aqueous solution. Chitosan (CS) films had been prepared by using solvent casting with mild drying for this purpose. The CS films were characterized by X-ray diffraction, field-emission scanning electron microscopy, and Fourier transform infrared (FTIR) spectroscopy. The performance of RB19 removal using CS were evaluated by varying contact time, solution pH, initial dye concentration, and adsorbent dosage. Adsorption isotherms, kinetics, and desorption were investigated by batch experiments. Results showed that CS films exhibited the optimal adsorption performance for RB19 removal and high maximum adsorption capacities of RB19, which were 799 and 822.4 mg g−1 at 20 and 40 °C, respectively. Adsorption kinetic data were well described by the pseudo-second-order kinetic model. FTIR analyses further indicated that interactions between RB19 and the CS film occurred during adsorption. The CS films also exhibited satisfactory desorption of RB19 at about 80 % after 30 min of desorption at pH 11. Our study demonstrated that the CS films can be easily prepared and applied for effective removal of RB19 in treatment of wastewater.

The pursuit for renewable sources of energy has increased rapidly due to the continuous depletion of non-renewable sources. Supercapacitors have attracted considerable attention because they can store electrical energy. In this study, a hierarchical mesoporous carbon sphere@nickel cobalt sulfide (CS@Ni–Co-S) core–shell was synthesized using a facile hydrothermal method. The reaction involved green synthesis without further sulfurization or post-heat treatment. The CS@Ni–Co-S core–shell microstructures exhibited a high capacitance of 724.4 F g− 1 at 2 A g− 1 in a 6 M KOH electrolyte. Good specific retention of 86.1% and high Coulombic efficiency of 97.9% were obtained after 2000 charge–discharge cycles. High energy density (58.0 Wh kg− 1 at 1440 W kg− 1) and high power density (34.2 Wh kg− 1 at 7200 W kg− 1) were observed. Through this study, a cost-effective and simple synthesis of CS@Ni–Co-S as an active electrode showed favorable electrochemical performance.

Polyaniline (PANI)- and multi-walled carbon nanotubes (MWCNTs)-intercalated reduced graphene oxide (rGO) aerogel or PANI/MWCNTs/rGO aerogel (PCGA) was prepared using a one-step hydrothermal co-assembly method for supercapacitor applications. The prepared aerogel exhibited an outstanding porous structure, and showed excellent capacitive performance. PANI and the MWCNTs were dispersed well on the graphene walls of the aerogels and spaced inner graphene layers to encourage electrolyte ion absorption. Accordingly, the specific capacitance of the PCGA was increased to 987 F/g at a scan rate of 0.5 A/g, which strongly surpassed that of the MWCNT/rGO aerogel (CGA) and PANI/rGO aerogel (PGA) with a specific capacitance of 335 and 643 F/g, respectively. PCGA also showed long term cycling stability (94% after 1000 cycles), which is promising as a potential electrode material for supercapacitors.

Tar is the undesired viscous black liquid produced during the gasification of biomass. Catalytic elimination of tar is feasible and is economically promising. In the present investigation, we performed first-principles calculations (i) to elucidate the decomposition mechanism of tar on the popular nickel (Ni) catalyst and (ii) to reveal the promotional effect of boron (B) in improving the activity and stability of the Ni catalyst for tar decomposition. Being the most abundant component of tar, toluene was chosen as a model compound. On the Ni(111) surface, toluene adsorbs strongly in a bridge configuration and the activation barrier for methyl C–H dissociation is 72 kJ mol−1. Toluene can further decompose on the Ni(111) surface via stepwise dehydrogenation of the methyl group. The aromatic C–H bond at the ortho position could only be activated after the complete dehydrogenation of the methyl group, which is followed by subsequent ring opening (activation barriers are 112 and 84 kJ mol−1, respectively) and C–C cleavages, to generate smaller hydrocarbons. The incorporation of subsurface B into the Ni catalyst (B–Ni) results in a corrugated Ni top surface and toluene adsorbs more strongly by 11 kJ mol−1 on the B–Ni catalyst than on pure Ni. Although the mechanism of toluene decomposition remains unchanged after doping with boron, the decomposition of toluene is significantly promoted on B–Ni. The activation barrier for the first methyl C–H dissociation on B–Ni is reduced to 51 kJ mol−1. Subsequent methyl C–H activations are also promoted on the B–Ni catalyst, but to a smaller extent. The aromatic C–H activation is also strongly promoted (89 kJ mol−1vs. 112 kJ mol−1 on pure Ni). Additional calculations on stepped surface models of Ni show that the activation barriers of toluene decomposition on the B–Ni surface are very close to those on B5 and F4 step sites of pure Ni, thus suggesting that the promotional effect of B on the catalytic activity of Ni could be mainly attributed to the creation of step-like corrugations on the Ni surface. These corrugations could also inhibit the formation of graphene-like structures on B–Ni.

We prepared a series of Nb2O5 polymorphs by the sol-gel method and the sol-gel hydrothermal method. Gold nanoparticles supported on Nb2O5 were prepared by solid grinding method. Au on pseudohexagonal (TT-phase) Nb2O5 containing an amorphous phase exhibited higher catalytic activity for CO oxidation than did other Au/Nb2O5 polymorphs. For the electrochemical properties for cathode materials of Li-ion batteries, Nb2O5 (TT) exhibited high capacity of 208 mA h g-1, and the deposition of Au onto Nb2O5 (TT) improved the capacity to 232 mA h g-1. Capacity and CO oxidation activity were related; the higher the catalytic activity Au/Nb2O5 shows, the higher is the discharging capacity. From the characterization results, Nb2O5 (TT) contains oxygen vacancies (Nb4+ sites), and the oxygen vacancies of Nb2O5 (TT) would play an important role for CO oxidation and the performance for Li-ion batteries.

For the first time, the nanoflower-like zinc borate compound was obtained by precipitation at room temperature using zinc oxide nanoparticles as a precursor. The obtained zinc borates were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), thermal gravimetric analysis (TGA), and Raman spectroscopy analysis. Monoclinic of zinc borate 2ZnO. 3B2O3.3.5H2O was achieved under the XRD pattern and the elemental chemical analysis. The particle size of the obtained materials is approximately 5 nm using TEM analysis. The TGA shows that the achieved zinc borate is outstanding stable at high temperatures. The result of this work provides a new route for the fabrication of zinc borate nanoparticle, which could be widely used in many applications.

A composite system composed of SrFe12O19 (SFO) and La0.5Ca0.5MnO3 (LCMO) was prepared by a two-stage sol–gel/hydrothermal synthesis technique. Starting conditions were varied to obtain products with 1:1 and 1:2 M ratios of SFO:LCMO. The morphology and composition of the composites were characterized by SEM and room-temperature Mossbauer spectroscopy, revealing the growth of nanocrystalline La0.5Ca0.5MnO3 particles (d ⩽ 150 nm) on the surface of SrFe12O19 platelets. Mossbauer spectra not only confirm the presence of well-formed M-type hexagonal ferrite in the composite materials, but also demonstrate the formation of a new, intermediate phase La0.5Ca0.5Mn(Fe)O3 at the interface between SFO and LCMO. The signature of the intermediate Fe-containing phase increases with the starting molar content of La0.5Ca0.5MnO3, as a greater fraction of the SrFe12O19 surface is covered by La0.5Ca0.5MnO3, increasing the total interfacial area. The trends in coercivity in the series of samples between 10 K and 300 K are reported and discussed in terms of sample morphology.

This paper reports an easy technique for immobilization of the DNA to the conducting polymer polypyrrole nanowires (PPy NWs). The nanowires were electrochemically synthesized on the surface of working electrode in the presence of gelatin as a soft mold. The structure of obtained PPy NWs was investigated by Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR) spectroscopy and Surface Enhanced Raman Spectroscopy (SERS). The DNA strands were directly immobilized on the PPy NWs. The amino groups at the up-end of the PPy nanowires facilitate the linkage with the phosphate groups of the probe DNA. The DNA immobilization and hybridization were characterized by Electrochemical Impedance Spectroscopy (EIS). The initial results show that the sensor responses to 10 pM of DNA sequence in the solution.

In this work, graphene oxide was reduced at low temperature using ascorbic acid and urea as the reductant. The obtained reduced graphene oxides were characterized by Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller surface area measurements (BET), scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), Raman spectroscopy and LECO combustion analysis. Bath adsorption experiments onto methylene blue were carried out to study the effect of adsorbents based on adsorbent dosage, pH solution and contact time parameters. Graphene oxide reduced by ascorbic acid shows a higher adsorption capacity comparing with using urea as a reductant. The adsorption capacities of both adsorbents were fully agreed with their specific surface areas and the degree of restoration of π-conjugation parameters.

Recently, there has been an increasing need of efficient synthetic protocols using eco-friendly conditions including low costs and green chemicals for production of metal nanoparticles. In this work, silver nanoparticles (silver NPs) with average particle size about 10 nm were synthesized by using a thermal decomposition technique. Unlike the colloidal chemistry method, the thermal decomposition method developed has advantages such as the high crystallinity, single-reaction synthesis, and easy dispersion ability of the synthesized NPs in organic solvents. In a modified synthesis process, we used sodium oleate as a capping agent to modify the surface of silver NPs because the oleate has a C18 tail with a double bond in the middle, therefore, forming a kink which is to be effective for aggregative stability. Importantly, the as-synthesized silver NPs have demonstrated strong antimicrobial effects against various bacteria and fungi strains. Electron microscopic studies reveal physical insights into the interaction and bactericidal mechanism between the prepared silver NPs and tested bacteria in question. The observed excellent antibacterial and antifungal activity of the silver NPs make them ideal for disinfection and biomedicine applications.

The temperature dependence of the electrical resistivity in (1 − x ) La 0.7 Ca 0.3 MnO 3 + x Ag composites has been investigated between 5 and 300 K for H = 0 and 3 T . Ag addition has increased the conductivity of this system. Curie temperature ( T C ) is almost independent of Ag content and is ~ 260 K for all the samples, while the metal–insulator transition temperature ( T MI ) increases with increasing content of Ag. The ρ–T of all samples fit well with the phenomenological percolation approach, which is based on the phase segregation of ferromagnetic metallic clusters and paramagnetic insulating regions. In addition, all the samples clearly reveal the unusual low temperature resistivity minimum. Analysis of our results in terms of the model based on charge carrier tunneling between the anti-ferromagnetically coupled grains shows excellent agreement with the experiment data for both H = 0 and 3 T .

The technological settings of a modified sol-gel method for the preparation of highly fine homogeneous powder of Ca2CuO3 doped with uranium 238 (x= 0.0–0.05) is presented. The analysis of structure, purity of phases and the justification for the role of uranium in the given compounds are provided, together with an almost complete classification of the observed optical phonons by means of Raman, IR measurements and ab initio calculations. A significant reduction in particle size was achieved by doping, and a strong correlation between resistivity and doping concentration was observed and explained using the phonon-assisted electron hopping conduction model. The persistence of a covalent insulation state in all compounds is an interesting feature of this doping.

Iron-based magnetic uids are widely used in physical applications. Recently, they have been extended to many biological applications due to their magnetic and biocompatible properties. However, their stability under an ambient environment still has not been systematically investigated. In this report, we present the oxidation process of magnetic uids. The oxidation process depends on the materials that make the nanoparticles, the di usion of oxygen atoms from the environment to the magnetic nanoparticles, which mainly depends on the viscosity of the solution and the surfactant that coats the nanoparticles. We suggest three ways to protect nanoparticles from oxidation: (a) using highly viscous carrier liquid (b) using relevant surfactants and (c) substitution of Ni2+ and Co2+ for Fe2+ in magnetite. Methods (a) and (b) are general, so they can be applied for many environmentally sensitive magnetic uids. Method (c) is speci c for a magnetite uid.

Grain size has marked effects on charge-ordering and other properties of Nd(0.5)A(0.5)MnO(3) (A=Ca or Sr). Thus, the anti-ferromagnetic (AFM) transition in Nd0.5Ca0.5MnO3 is observed distinctly only in samples sintered at 1273 K or higher. The sample with a small grain size (sintered at 1173 K) shows evidence for greater ferromagnetic (FM) interaction at low temperatures, probably due to phase segregation. The FM transition as well as the charge-ordering transition in Nd0.5Sr0.5MnO3 becomes sharper in samples sintered at 1273 K or higher. The sample sintered at 1173 K does not show the AFM-CO transition around 150 K and is FM down to low temperatures; the apparent T-c-T-co gap decreases with the increase in the grain size. The samples sintered at lower temperatures (

This paper addresses the problem of identifying a very small subset of data points that belong to a significantly larger massive dataset (i.e., Big Data). The small number of selected data points must adequately represent and faithfully characterize the massive Big Data. Such identification process is known as representative selection [19]. We propose a novel representative selection framework by generating an l1 norm sparse graph for a given Big-Data dataset. The Big Data is partitioned recursively into clusters using a spectral clustering algorithm on the generated sparse graph. We consider each cluster as one point in a Grassmann manifold, and measure the geodesic distance among these points. The distances are further analyzed using a min-max algorithm [1] to extract an optimal subset of clusters. Finally, by considering a sparse subgraph of each selected cluster, we detect a representative using principal component centrality [11]. We refer to the proposed representative selection framework as a Sparse Graph and Grassmann Manifold (SGGM) based approach. To validate the proposed SGGM framework, we apply it onto the problem of video summarization where only few video frames, known as key frames, are selected among a much longer video sequence. A comparison of the results obtained by the proposed algorithm with the ground truth, which is agreed by multiple human judges, and with some state-of-the-art methods clearly indicates the viability of the SGGM framework., Comment: This paper has been withdrawn by the author due to lacking details

Key frame extraction algorithms consider the problem of selecting a subset of the most informative frames from a video to summarize its content., Comment: This paper has been withdrawn by the author due to a crucial sign error in equation 1

Bulk manganites of the form La${}_{5/8\ensuremath{-}}$${}_{y}$Pr${}_{y}$Ca${}_{3/8}$MnO${}_{3}$ (LPCMO) exhibit a complex phase diagram due to coexisting charge-ordered antiferromagnetic (CO/AFM), charge-disordered paramagnetic (PM), and ferromagnetic (FM) phases. Because phase separation in LPCMO occurs on the microscale, reducing particle size to below this characteristic length is expected to have a strong impact on the magnetic properties of the system. Through a comparative study of the magnetic and magnetocaloric properties of single-crystalline (bulk) and nanocrystalline LPCMO ($y$$\phantom{\rule{0.16em}{0ex}}=\phantom{\rule{0.16em}{0ex}}$3/8) we show that the AFM, CO, and FM transitions seen in the single crystal can also be observed in the large particle sizes (400 and 150 nm), while only a single PM to FM transition is found for the small particles (55 nm). Magnetic and magnetocaloric measurements reveal that decreasing particle size affects the balance of competing phases in LPCMO and narrows the range of fields over which PM, FM, and CO phases coexist. The FM volume fraction increases with size reduction, until CO is suppressed below some critical size, \ensuremath{\sim}100 nm. With size reduction, the saturation magnetization and field sensitivity first increase as long-range CO is inhibited, then decrease as surface effects become increasingly important. The trend that the FM phase is stabilized on the nanoscale is contrasted with the stabilization of the charge-disordered PM phase occurring on the microscale, demonstrating that in terms of the characteristic phase separation length, a few microns and several hundred nanometers represent very different regimes in LPCMO.

The technological settings of a modified sol-gel method for preparation of highly fine homogeneous powder Ca2CuO3 doped with uranium 238 (x=0-0.05) is presented. The analysis of structure, purity of phases and the justification for the role of uranium in the given compounds are provided together with almost complete classification of observed optical phonons by means of the Raman, IR measurements and ab initio calculation. The significant reduction in particle size was achieved by doping and the strong correlation between resistivity and doping concentration was observed and explained using the phonon-assisted electron hopping conduction model. The persistence of covalent insulation state in all compounds is a key feature of this class of compounds., Comment: 32 pages, 10 figures

Percolation theory has been involved to explain the temperature dependence of conductivity in the K-doped perovskite ruthenates and to estimate the resistivity of grain boundary in the percolative conduction regime. Using the two-layer simple effective medium model [A. Gupta, G.Q. Gong, G. Xiao, P.R. Duncombe, P. Lecoeur, P. Trouilloud, Y.Y. Wang, V.P. Dravis, J.Z. Sun, Phys. Rev. B 54 (1996) R15629] and assuming the scaling property of grain boundary system, we have obtained the new formula for grain boundary resistivity, which contains important factors for the grain size, boundary thickness, and boundary fractal dimension. The numerical results for the system A 0.5 K 0.5 RuO 3 (A=La, Y, Nd, Pr) are in very good agreement with the experiment. Importantly, it reveals that the percolative conduction plays a significant role in ceramic compounds containing polycrystalline grains and grain boundaries.

Mesoporous MgO has been synthesized in the presence of the neutral block co-polymer surfactant Pluronic F127. The characterization of synthesized material was carried out by mean of X-ray diffraction (XRD), scanning electron microscope (SEM) and Brunauer-Emmett-Teller technique (BET). The obtained MgO exhibited a value of the surface area of 157 m 2 /g and showed a narrow pore size distribution centered at 4.3 nm. The phenomena and gas evolved during calcinations have been investigated by thermogravimeter-mass spectrometer (TG-MS). During the calcinations, the precursor Mg(OH) 2 was converted to MgO with a mass loss of 29% and with the formation of H 2 O (>60% of the gas evolved). The desorption of CO 2 and a small amount of CO and/or N 2 which were adsorbed from air on the surface of Mg(OH) 2 were also observed. No organic compounds were found which indicated that F127 was completely removed by Soxhlet extraction.

SrFe12O19/La1−xCaxMnO3 (SFO/LCMO) composites with x = 0.1 and 0.5 were synthesized via a two stage combined citrate precursor sol-gel and hydrothermal method. The structure and composition of the samples were refined from the X-ray diffraction patterns. The morphologies of the composites were investigated using transmission and scanning electron microscopies, which revealed micron-sized hexagonal platelets of SFO with LCMO particles with average diameters of 110–130 nm formed at the surface. An investigation of the temperature and field dependence of the magnetization found that the SFO phase with a ferrimagnetic characteristic up to 720 K dominates the magnetic properties of the composite samples. The SFO/LCMO composite samples showed a reduction in saturation magnetization and coercivity when compared with pure SFO. However, low temperature hysteresis loops recorded after cooling in applied fields up to 5 T revealed the absence of exchange bias in the SFO/LCMO composite, ruling out the possibility of si...

Magnetic Fe3O4 nanoparticles (Fe3O4 NPs) were synthesized by co-precipitation (of Fe2+ and Fe3+) and surface-carboxylated by poly(styrene-co-acrylic acid) (PSA). Then they were thoroughly characterized by Scanning Electron Microscope and Transmission Electron Microscope analyses. Using glutaraldehyde cross-linking immobilization strategy, cholesterol oxidase (ChOx) was immobilized onto Fe3O4/PSA microspheres. The Fe3O4/PSA-ChOx has been successfully synthesized on the planar platinum polyaniline (PANi) modified electrode. PANi/Fe3O4/PSA-ChOx sensing properties were studied using cyclic voltammetric and chronoamperometric techniques. Under the optimized experimental conditions the biosensor shows excellent features, such as wide linear range, 0.2 to 1.8 mM (R2 = 0.9901), low detection limit (0.02 mM), short response time (5–10 s), and high sensitivity (8796 μA mM−1 cm−2). The interference test with selected organic compounds, such as glucose, ascorbic acid, uric acid, and acetaminophen indicated high selectivity of the above sensor. It can be proven that the proposed PANi/Fe3O4/PSA-ChOx based sensing concept could be successfully used for other biodetections.

Hard magnetic strontium hexaferrite SrFe 12 O 19 nanoparticles were synthesized by the sol–gel hydrothermal method. The factors affecting the synthesized process, such as the mole proportion of the reactants, pH, temperature, the hydrothermal conditions and the calcination process, have been investigated. The crystal structures of these materials were refined by Rietveld method. The obtained materials have single crystal phase, equal nano-size, plate shape and high anisotropy. The high magnetic coercivity of 6.3 kOe with the magnetization at 11.1 kOe of 66 emu g −1 at room temperature was observed for the strontium hexaferrite nanoparticles. For other nanoparticles (SrLn x Fe 12-x O 19 and SrFe 12 O 19/CoFe 2 O 4) synthesized on the basis of SrFe 12 O 19 the complex completion of the crystal structure distortion and the interaction between magnetic phases were observed.

Highly homogeneous finely powdered Ca2CuO3 has been prepared by the sol?gel technique. No evidence for CaO and CuO impure phases was observed. The single-phase purity was observably better than that of samples prepared by the ceramic method and oxalate co-precipitation. On the basis of the structural parameters determined, the bond valence sum approach was involved in explaining the weak interchain direct Cu?Cu covalent bonding. The I?V and ?(T) measurements showed constant semiconductor behaviour with resistivity increase above 108???cm in the low temperature region. The fitting of ?(T) using a band gap model gave an activation energy as small as 0.19?eV. This finding demonstrates well the covalent insulator nature of this system.

A tunable diode laser (TDL) operating in the region of 2150 to 2350 cm⁻¹ wavenumber is used in this work to investigate the dynamics of level populations in CO₂ lasers. The wide tunability of the TDL is exploited in determining the populations in any level of the CO₂ molecule. Thus, the vibrational population distributions in a CW CO₂ laser discharge under both lasing and non-lasing conditions are measured and are compared with the mode temperature model. The relaxation processes associated with the upper and lower levels of CO₂ lasers are also investigated. In particular, the electron excitation and de-excitation rates of the upper laser level in typical CO₂ discharges are determined directly from the experiment, and it is shown that electron de-excitation is responsible for the saturation of v₃ mode temperature in electrically excited CO₂ lasers at high discharge currents, and imposes a fundamental limitation on the gain attainable in CO₂ lasers. The relaxation of the lower laser level is complicated by the occurrence of several competitive vibration-vibration (V-V) processes. The TDL measurements enable us, for the first time, to monitor separately the population in all levels of concern to the relaxation of the lower laser level and to determine the rate constant of each of the available decay channels. It is shown that the O2²O level plays an important role in the relaxation of the lower laser level. Doctor of Philosophy (PhD)