bluuebunny/crossref_metadata_2025 huggingface dataset:
Strain improvement by mutation for enhanced production of starch‐saccharifying glucoamylase from Bacillus licheniformis
Authors: Ghani Maria , Aman Afsheen , Rehman Haneef U. , Siddiqui Nadir N. , Qader Shah A. U.
Published: October 2014

A natural isolate, Bacillus licheniformis KIBGE‐IB3, was subjected to mutational analysis for the enhanced production of glucoamylase. Randomly generated mutants were initially screened for enzyme production and after secondary screening B. licheniformis KIBGE‐IB3M67 demonstrated maximum glucoamylase production with improved starch saccharifying capability. Enzyme activity from KIBGE‐IB3M67 reached up to 25 kU/mg by strain improvement, which was nearly twofold increase in enzyme production as compared to the parent strain. SEM revealed that raw potato starch is more profoundly hydrolyzed when treated with mutant glucoamylase. Successful mutation also reduced the fermentation time from 48 to 24 h for glucoamylase production, optimum fermentation pH and temperature slightly shifted from 7.0 (wild) to 7.5 (mutant), from 30 to 50°C (wild), and from 20 to 55°C (mutant), respectively. Reduction in fermentation time and enhanced starch saccharification ability makes this mutant (KIBGE‐IB3M67) an attractive candidate for the production of glucoamylase at commercial level.
Impact of freezing and thawing processes on wheat and potato starch gel syneresis
Authors: Freschi Jérôme , Doran Lynn , Malumba Paul , Blecker Christophe
Published: October 2014

The impact of freezing and thawing processes on gel structure, bound states, and mobility of water in wheat and potato starch gels was investigated, using laser scattering granulometer, centrifugation, SEM, DSC, and thermogravimetrical analysis (TGA). Starch gel water syneresis was qualitatively and quantitatively correlated to the freezing–thawing process. Potato microstructure was mainly impacted by freezing rates whereas wheat was influenced by both freezing and thawing rates. The observations were confirmed by SEM. Indeed, the size of cavities created by ice crystals increased with higher freezing rates for both varieties. Microstructure modifications during thawing only appeared for wheat. The hypothesis to explain the difference between these two starch gels could be based on the structural feature of starch granules that induce modifications of the gel matrix hardness depending on the granule restructuration during the heating period of the preparation of these gels.
Hydroxypropyl derivatives of legume starches: Functional, rheological and thermal properties
Authors: Oladebeye Abraham Olasupo , Oshodi Aladesanmi Augustine , Amoo Isiaka Adekunle , Karim Alias Abd
Published: October 2014

Hydroxypropyl derivatives were prepared from the native starches isolated from lima bean and jack bean. Both native and hydroxypropylated starches were evaluated for functional, rheological and thermal properties. Molar substitution (MS) value ranged from 0.24 to 0.37 while degree of substitution (DS) from 0.02 to 0.04. The values of swelling power, solubility and pasting parameters of the native starches were significantly different from the hydroxypropyl derivatives with deviations of insignificant difference obtained for lima bean starches. Non‐Newtonian shear‐thinning behaviour was exhibited by all the samples. Their viscosity consistency, K, deduced from Herschel–Bulkley model, increased progressively with MS. Starches at low‐substitution possessed high shear viscosities compared to the native and high‐substituted starches. Increase in yield stress (σo) was observed at low‐substitution level and decrease at high‐substitution level of hydroxypropylation. Upon hydroxypropylation, enthalpies of gelatinisation (ΔHgel) increased whereas the transition gelatinisation temperatures (To, Tp and Tc) decreased. Comparatively, lower values of transition temperature and enthalpy were obtained for retrograded starch gels than the gelatinised gels. Upon hydroxypropylation, native starches experienced increase in MW and polydispersity index (PDI). All the native starches exhibited type‐A XRD patterns, which remained unchanged after hydroxypropylation.
Physicochemical properties of starch extracted from Colocasia esculenta (L.) Schott (Bun‐long taro) grown in Hunan, China
Authors: Zeng Fan‐Kui , Liu Hong , Liu Gang
Published: October 2014

Taro (Colocasia esculenta (L.) Schott) starch was extracted from the corms of Bun‐long taro cultivated in Hunan, China, and its physicochemical properties were determined and compared with those of potato and sweet potato starches. Bun‐long taro starch had an irregular, polygonal shape, and grains were small in size: the surface‐average granule diameter ranged from 1.3 to 2.2 µm. Amylose content in Bun‐long taro starch was 8.4 ± 0.2%, determined by dual‐wavelength colorimetry, and the starch had an A‐type XRD pattern. The onset temperature (To), peak temperature (Tp), and completion temperature of gelatinization (Tc) associated with Bun‐long taro starch were 73.6, 80.3, and 88.3°C, respectively, determined by DSC. According to the Brabender amylograph paste viscosity analysis, the viscosity of Bun‐long taro starch started increasing at 77°C, which was higher than the temperatures at which the viscosities of potato starch and sweet potato starch started increasing.
Factors affecting starch utilization in large animal food production system: A review
Authors: Giuberti Gianluca , Gallo Antonio , Masoero Francesco , Ferraretto Luiz Felipe , Hoffman Patrick C. , Shaver Randy D.
Published: October 2014

Dietary starch from feed grains represent the major energy‐yielding sources in diets for large animals and starch effective digestion has a great impact on animal energy intake for meeting the substantial energy requirement to improve meat or milk productions. In general, site, extent and rate of starch digestion are affected by intrinsic and external factors that can be interrelated and are thus not easily defined. As a consequence, research to obtain a deeper knowledge on how starch chemical and structural compositions may affect starch digestion potential of feed grains and therefore their nutritional value has progressed recently. The objectives of this review are: (1) to give an overview on inherent starch primary structures and interactions with other compounds within feed grains; (2) to discuss factors affecting starch digestion potential in feed grains; (3) to explore starch digestion mechanism, and linkages with animal performances, both for swine and ruminants. The criticism of methods commonly used to estimate starch digestibility from feed grains for swine and ruminants are also discussed.
A survey of expert attitudes on understanding and governing energy autonomy at the local level
Authors: Radzi Anis
Published: October 2014

Local governments around the world pursue a range of activities to reduce local greenhouse gas emissions, increase energy efficiency, and promote locally generated renewable energy. Yet many underestimate the potential their locality possesses in becoming fully energy efficient and self‐sufficient, and in particular, tapping into the natural potential, which exists on rooftops, facades, underground, in streams, fields, and forests for locally generated renewable energy, harvested in a sustainable manner. This lack of awareness has effected the perception and motivation of local governments to pursue energy projects with more lasting environmental effects. This survey of international experts in energy, local governance, and urban planning reveals that most were of the opinion that existing structures within local government were capable of pursuing energy autonomy, provided that a thorough review of existing levels of knowledge, logistical arrangements, and financial capacities is carried out to determine whether they are indeed capable of fulfilling the necessary functions and to carry out the necessary activities. The establishment of energy development entities outside the established structure, that are also accountable to the local government, can only be considered once the aforementioned analyses show that adjustments within the existing organization would be difficult to achieve. This is an original review of international expert attitudes on local renewable energy autonomy, conducted in 2011 and 2012 among 77 local energy experts. WIREs Energy Environ 2015, 4:397–405. doi: 10.1002/wene.152

This article is categorized under:

Energy and Climate > Economics and Policy

Energy Policy and Planning > Economics and Policy

Energy and Development > Economics and Policy
SERS Nanosensors and Nanoreporters: Golden Opportunities in Biomedical Applications
Authors: Vo‐Dinh Tuan , Liu Yang , Fales Andrew M. , Ngo Hoan , Wang Hsin‐Neng , Register Janna K. , Yuan Hsiangkuo , Norton Stephen J. , Griffin Guy D.
Published: October 2014

This article provides an overview of recent developments and applications of surface‐enhanced Raman scattering (SERS) nanosensors and nanoreporters in our laboratory for use in biochemical monitoring, medical diagnostics, and therapy. The design and fabrication of different types of plasmonics‐active nanostructures are discussed. The SERS nanosensors can be used in various applications including pH sensing, protein detection, and gene diagnostics. For DNA detection the ‘Molecular Sentinel’ nanoprobe can be used as a homogenous bioassay in solution or on a chip platform. Gold nanostars provide an excellent multi‐modality theranostic platform, combining Raman and SERS with two‐photon luminescence (TPL) imaging as well as photodynamic therapy (PDT), and photothermal therapy (PTT). Plasmonics‐enhanced and optically modulated delivery of nanostars into brain tumor in live animals was demonstrated; photothermal treatment of tumor vasculature may induce inflammasome activation, thus increasing the permeability of the blood brain‐tumor barrier. The imaging method using TPL of gold nanostars provides an unprecedented spatial selectivity for enhanced targeted nanostar delivery to cortical tumor tissue. A quintuple‐modality nanoreporter based on gold nanostars for SERS, TPL, magnetic resonance imaging (MRI), computed tomography (CT), and PTT has recently been developed. The possibility of combining spectral selectivity and high sensitivity of the SERS process with the inherent molecular specificity of bioreceptor‐based nanoprobes provides a unique multiplex and selective diagnostic modality. Several examples of optical detection using SERS in combination with other detection and treatment modalities are discussed to illustrate the usefulness and potential of SERS nanosensors and nanoreporters for medical applications. WIREs Nanomed Nanobiotechnol 2015, 7:17–33. doi: 10.1002/wnan.1283

This article is categorized under:

Diagnostic Tools > Biosensing

Diagnostic Tools > Diagnostic Nanodevices

Diagnostic Tools > In Vivo Nanodiagnostics and Imaging
Pharmacokinetics of metallic nanoparticles
Authors: Lin Zhoumeng , Monteiro‐Riviere Nancy A. , Riviere Jim E.
Published: October 2014

Metallic nanoparticles (NPs) have been widely applied in the field of nanomedicine. A comprehensive understanding of their pharmacokinetics is crucial for proper risk assessment and safe biomedical applications. This review focuses on gold and silver (Ag) NPs, and briefly discusses iron oxide, titanium dioxide (TiO2), and zinc oxide NPs. Pharmacokinetics of metallic NPs depends on the particle type, size, surface charge, surface coating, protein binding, exposure route, dose, and species. Generally, blood half‐life is shorter in rodents than in larger laboratory animals (e.g., rabbits or monkeys) and differs between intravenous and oral exposures. Oral, dermal, or inhalational absorption is low (≤5%), but may increase with smaller sizes, negative charge, and appropriate coatings. Metallic NPs can be distributed throughout the body, primarily accumulating in the liver, spleen, and lymph node due to nonspecific uptake by reticuloendothelial cells, and could remain in the body for ≥6 months. Metallic NPs (≤100 nm) can cross the blood–brain barrier (BBB), favored by coating with BBB‐permeable neuropeptides. Placental transfer depends on the stage of embryonic/placental maturation and surface composition, and may be enhanced by coating with biocompatible molecules (e.g., ferritin or polyethylene glycol). Renal and biliary excretion is generally low due to persistent accumulation in tissues, but renal elimination could be substantially increased with smaller sizes and specific coatings (e.g., glutathione). Physiologically based pharmacokinetic models for gold/dendrimer composite nanodevices, AgNPs, and TiO2NPs have been developed in rats and the AgNP and TiO2NP models have been extrapolated to humans to support risk assessment and nanomedicine applications. WIREs Nanomed Nanobiotechnol 2015, 7:189–217. doi: 10.1002/wnan.1304

This article is categorized under:

Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials
Synthesis and Characterization of Few‐layer Nanosheets of GaN and Other Metal Nitrides
Authors: Sreedhara M. B. , Vasu K. , Rao C. N. R.
Published: October 2014

By making use of the fact that single‐ and few‐layer nanosheets of GaS and GaSe are readily obtained by micromechanical cleavage because of their mica‐like morphology, we were able to prepare GaN nanosheets by the reaction of these chalcogenide nanosheets with ammonia at 600–650 °C. The nitride nanosheets were characterized by transmission electron microscopy, atomic force microscopy, and other methods. Few‐layer VN was obtained by high‐temperature ammonolysis of exfoliated V2O5 sheets. Ammonolysis of MoO3 and MoS2 nanosheets yields the nitride nanosheets.
Multiple stacking of InGaAs/GaAs (731) nanostructures
Authors: Xie Y. Z. , Kunets V. P. , Wang Z. M. , Dorogan V. , Mazur Y. I. , Wu J. , Salamo G. J.
Published: October 2014

We studied the multilayering effects of InGaAs quantum dots (QDs) on GaAs(731), a surface lying inside of the stereographic triangle. The surfaces after stacking 16 InGaAs layers were characterized with highly non-uniformity of QD spatial distribution. The bunched step regions driven by strain accumulation are decorated by QDs, therefore GaAs(731) becomes a good candidate substrate for the growth of QD clusters. The unique optical properties of the QD clusters are revealed by photoluminescence measurements. By adjusting the coverage of InGaAs, a bamboo-like nanostructured surface was observed and the quantum dots aligned up in clusters to separate the “bamboo” into sections.
Tuning the morphologies of SiC nanowires via the change of the CoxSiy melts
Authors: Chen J. J. , Pan Y. , Tang W. H. , Shi Q.
Published: October 2014

SiC nanowires and SiC/SiO2 core-shell structural nanowires were synthesized via a simple thermal evaporation of CoxSiy melts at the temperature of 1500°C. The morphologies and yields of those SiC nanowires can be tuned by altering the composition of CoxSiy. Nanowires obtained by thermal evaporation of CoSi are composed of SiC/SiO2 core-shell nanostructures with lengths up to several hundreds of micrometers, diameters of 40∼50 nm, and the thickness of amorphous SiO2 wrapping shell about 20 nm. SiC nanowires prepared by thermal evaporation of CoSi2 and Co2Si melt are found to be hexagonal-prism-shaped nanorods, and the diameter of those nanorods is about 150 nm and the length is about 10 microns. All the SiC nanowires obtained possess [111] preferred growth direction with a high density stacking faults and twin defects. Taking into consideration the binary alloy diagram of CoSi and the participation of oxygen, we propose the vapor-solid growth mechanism of SiC nanowires and discuss the effect of the supersaturation of SiO on the morphology and yields of SiC nanowires.
Fabrication and characteristics of nitrogen-doped nanocrystalline diamond/p-type silicon heterojunction
Authors: Lu D. , Li H. D. , Cheng S. H. , Yuan J. J. , Lv X. Y.
Published: October 2014

Nitrogen-doped nanocrystalline diamond films (N-NDFs) have been deposited on p-type silicon (Si) by microwave plasma chemical vapor deposition. The reaction gases are methane, hydrogen, and nitrogen without the conventional argon (Ar). The N-NDFs were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. The grain sizes are of 8∼10 nm in dimension. The N-NDF shows n-type behavior and the corresponding N-NDF/p-Si heterojunction diodes are realized with a high rectification ratio of 102 at ∼ 7.8 V, and the current density reaches to 1.35 A/cm2 at forward voltage of 8.5 V. The findings suggest that fabricated by CH4/H2/N2 without Ar, the N-NDFs and the related rectifying diodes are favorable for achieving high performance diamond-based optoelectronic devices.
The model developed for stress-induced structural phase transformations of micro-crystalline silicon films
Authors: Han Chang-Fu , Lin Jen-Fin
Published: October 2014

The nanoindentations were applied to island-shaped regions with metal-induced Si crystallizations. The experimental stress-strain relationship is obtained from the load-depth profile in order to investigate the critical stresses arising at various phase transitions. The stress and strain values at various indentation depths are applied to determine the Gibbs free energy at various phases. The intersections of the Gibbs free energy lines are used to determine the possible paths of phase transitions arising at various indentation depths. All the critical contact stresses corresponding to the various phase transitions at four annealing temperatures were found to be consistent with the experimental results.
Synthesis of silver nanoparticles by Lactobaciluus acidophilus 01 strain and evaluation of its in vitro genomic DNA toxicity
Authors: Namasivayam S. Karthick Raja , Gnanendra E. Kumar , Reepika R.
Published: October 2014

Silver nanoparticles synthesized by dried biomass of Lactobaciluus acidophilus 01 strain was evaluated against toxicity of genomic DNA isolated from bacteria (E. coli) fungi (Beauveria bassiana) algae (Seenedesmus acutus) and human blood adopting standard condition was discussed in the present study. Synthesized silver nanoparticles were characterized by UV-Vis spectroscopy and SEM. The UV-Vis spectroscopy revealed the formation of silver nanoparticles by yielding the typical silver plasmon absorption maxima at 430 nm and SEM micrograph indicates the uniform spherical particles within the size range of 45∼60 nm. The energy dispersive X-ray spectroscopy (EDX) of the nanoparticle confirmed the presence of elemental silver signal as strong peak. The above synthesized silver nanoparticles didn’t cause any toxic effect on all the tested genomic DNA at all tested concentrations which reveals nil genomic nanoparticles induced toxicity.
Passivated ZnSe nanocrystals prepared by hydrothermal methods and their optical properties
Authors: Peng Lingling , Wang Yuhua , Dong Qizheng , Wang Zhaofeng
Published: October 2014

Homogeneous ZnSe nanocrystals were prepared via surfactant-assisted hydrothermal method. Surfactants agent CTAB was used to control the particle morphology and the growth rate. The structure, morphology and optical properties of ZnSe nanocrystals have been investigated by XRD, TEM and luminescence spectroscopy. The results indicated that the size of ZnSe nanocrystals ranged from 3.0 nm to 5.0 nm with cubic zinc blende structure. ZnSe nanocrystals coated by CTAB were revealed high dispersibility and distribution under TEM. Compared to the bulk ZnSe, the absorption edges and photoluminescence peaks of ZnSe nanocrystals were blue shifted to higher energies due to the quantum confinement effect. The emission intensity was strengthened after coated CTAB compared to bare sample. This was mainly due to the surface passivation. Meanwhile, we simply explored the formation mechanism of ZnSe nanocrystal in hydrothermal system.
Towards the low temperature growth of uniform diameter multi walled carbon nanotubes by catalytic chemical vapour deposition technique
Authors: Somanathan Thirunavukkarasu , Pandurangan Arumugam
Published: October 2014

Mesoporous MCM-41 molecular sieves containing f-block transition elements (gadolinium) with various Si/Gd ratios (50, 75 and 100) were synthesised by a hydrothermal method. Their mesoporous structure was confirmed by X-ray diffraction, nitrogen sorption studies, thermogravimetric analysis, scanning and transmission electron microscopy. The local environment of Gd in the material was studied by electron paramagnetic resonance. The compatibility of the catalyst for the synthesis of uniform diameter CNTs by varying the temperature from 400 to 650°C with fixed flow rates of N2 and C2H2 (140 ml/min and 40 ml/min, respectively). The product is mostly metal containing thin MWCNTs with diameter of 10∼20 nm. Characterisation shows that a combination of Gd-MCM-41 (100) catalyst gives a high yield of high quality MWCNTs under optimum growth conditions.
Nano-Molecular Junctions on STM Tips
Authors: Huang Chun , Yang Jianshu
Published: October 2014

We present a technique for metal-organic-metal junctions, which contain ten or fewer conjugated molecules between each of such junction, and the investigations of the I–V response of these junctions. The junctions are made by self assembling thiolated molecules onto gold coated tips for use in scanning tunneling microscopy. We show that this easy technique probes the qualitative properties of the molecules. Current-voltage characteristics of a Tour wire and a new molecular rectifier are presented.
Synthesis and Thermal Behavior of Metallic Cobalt Micro and Nanostructures
Authors: Montiel Marlene González , Santiago-Jacinto P. , Góngora J. A. I. Díaz , Reguera E. , Rodríguez-Gattorno Geonel
Published: October 2014

In this contribution, a comparative study of metallic cobalt micro and nanoparticles obtained in solution by four different chemical routes is reported. Classic routes such as borohydride reduction in aqueous media and the so-called polyol methodology were used to obtain the cobalt nanostructures to be studied. Using CTAB as surfactant, cobalt hollow nanostructures were obtained. The use of strong reducing agents, like sodium borohydride, favors the formation of quasi-monodispersed nanoparticles of about 2 nm size but accompanied with impurities; for hydrazine (a mild reducer), nanoparticles of larger size are obtained which organize in spherical microagglomerates. Valuable information on the particles thermal stability and on nature of the species anchored at their surface was obtained from thermogravimetric curves. The samples to be studied were characterized from UV-vis, IR, X-ray diffraction, and electron microscopy images (scanning and transmission).
Synthesis and Photocatalytic Activity of Fe-doped TiO2 Supported on Hollow Glass Microbeads
Authors: Zhao Wenyan , Fu Wuyou , Yang Haibin , Tian Chuanjin , Li Minghui , Ding Juan , Zhang Wei , Zhou Xiaoming , Zhao Hui , Li Yixing
Published: October 2014

In this paper, Fe-doped TiO2photocatalyst supported on hollow glass microbeads (Fe-TiO2/beads) is prepared by dip-coating method, which uses hollow glass microbeads as the carriers and tetrabutylorthotitanate [Ti(OC4H9)4] as the raw material. The phase structure, ingredient, morphologies, particle size and shell thickness of the products are characterized by X-ray powder diffraction (XRD), energy-dispersive spectroscopy (EDS) and field emission scanning electron microscope (FESEM). The feasibility of photocatylic degradation of Rhodamine B (RhB) under illumination of UV-vis light is studied. The results show that the core-shell structure catalyst is composed of Fe-doped anatase TiO2and hollow glass microbeads, and the catalytic activity of the TiO2is markedly enhanced by Fe ion doping. The optimum concentration of Fe ion is 0.1% (molecular fraction) in the precursor and the photocatalytic activity can be increased to 98% compared with that of the undoped one. The presence of ferrum elements neither influences the transformation of anatase to rutile, nor creates new crystal phases. The possible mechanism of photocatalytic oxidation is also discussed.
Shape-controlled Synthesis of Porous SnO2 Nanostructures via Morphologically Conserved Transformation from SnC2O4 Precursor Approach
Authors: Wang Qihua , Wang Dewei , Wang Tingmei
Published: October 2014

Porous SnO2 nanostructures with controlled shapes were synthesized by a facile morphologically conserved transformation from SnC2O4 precursor approach. Well-defined SnC2O4 nanostructures can be obtained through a solution-based precipitation process at ambient conditions without any surfactant. The formation mechanism of such microstructures was tentatively proposed on the basis of intrinsic crystal structure and the reaction conditions. We found that the morphologies of precursor were well maintained while numerous pores were formed during the annealing process. The combined techniques of X-ray diffraction, nitrogen absorption-desorption, field emission scanning electron microscopy, and (high-resolution) transmission electron microscopy were used to characterize the as-prepared SnO2 products. Moreover, cyclic voltammetry (CV) study shows that the shape of CV presents a current response like roughly rectangular mirror images with respect to the zero-current line without obvious redox peaks, which indicating an ideal capacitive behavior of the SnO2 electrodes. The photoluminescence (PL) spectrum study suggests that the as-obtained porous SnO2 nanostructures might have a large number of defects, vacancies of oxygen, and local lattice disorder at the interface, interior and exterior surfaces.
Synthesis and Electrical Properties of TiO2 Nanoparticles Embedded in Polyamide-6 Nanofibers Via Electrospinning
Authors: Nirmala R. , Jeong Jin Won , Navamathavan R. , Kim Hak Yong
Published: October 2014

We report on the synthesis and characterizations of TiO2 nanoparticles embedded in polyamide-6 composite nanofibers by using electrospinning technique. The influence of substrate on the electrical characteristics of polyamide-6/TiO2 composite nanofibers was investigated. The resultant nanofibers exhibit good incorporation of TiO2 nanoparticles. The doping of TiO2 nanoparticles into the polyamide-6 nanofibers were confirmed by high resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. Photoluminescence (PL) and cathodoluminescence (CL) spectroscopy were also used to characterize the samples. The PL and CL spectra reveal that the as-spun polyamide-6/TiO2 composite nanofibers consisted of overlapping of two broad emission bands due to the contribution of polyamide-6 (centered at about 475 nm), which might originate from organic functional groups of polyamide-6 and TiO2 nanoparticles (centered around 550 nm). The electrical conductivity of the polyamide-6/TiO2 composite nanofibers on different substrates was carried out. It was found that the electrical conductivity of the polyamide-6/TiO2 composite nanofibers on silicon substrate was in the range of 1∼3 μA, and about 1 to 20 pA for the paper and glass substrates.
Synthesis and Characterization of CaF2 Nanoparticles with Different Doping Concentrations of Er3+
Authors: Song Jinghong , Zhi Guanglin , Zhang Yan , Mei Bingchu
Published: October 2014

The calcium fluoride nanoparticles with a variety of doping amounts of erbium ions were prepared by CTAB/C4H9OH/C7H16/H2O reverse micro-emulsion method. The nanoparticles were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), absorption and fluorescence spectra. The XRD patterns indicated a typical cubic fluorite structure and no other impurities. The TEM results showed one kind of particles with uniform grain size and without agglomeration were synthesized. The FTIR spectra revealed that there were some amounts of -OH, NO
3
−
and organic groups absorbed on the surfaces of the particles before being annealed. The absorption spectra presented many absorption peaks and bands corresponding to the rich energy levels of erbium ion. The Red-Shift of absorption bands and Blue-Shift of fluorescence peak could attribute to the weakened energy level split as a result of the decrease in crystal field strength.
One-Step Cutting of Multi-Walled Carbon Nanotubes Using Nanoscissors
Authors: Zhao Jiang , Liu Ping , Yang Zhi , Zhou Peng , Zhang Yafei
Published: October 2014

A novel, simple and effective one-step method has been developed to cut the conventional long and entangled multi-walled carbon nanotubes (MWCNTs) with nanoscissors. The cutting process was carried out by the interactive collision of CNTs with the silicon carbide particles adhered on the abrasive papers. The final cut nanotubes have an average length of 200∼300 nm. The statistical length distribution result indicates that cutting by this method achieves high cutting efficiency for short duration of 2 min. Shortened nanotubes are found to be easily dispersed into aqueous and ethanol solutions. The cut MWCNTs/copper composite thin film fabricated by combined electrophoresis and electroplating techniques reveals that MWCNTs after cutting are well distributed and adhered to the Cu matrix. This method is not only fast and efficient but also no chemical waste, which will expand many potential applications of CNTs.
Conductivity Study of Polyaniline-Cobalt Ferrite (PANI-CoFe2O4) Nanocomposite
Authors: Tanrıverdi E. E. , Uzumcu A. T. , Kavas H. , Demir A. , Baykal A.
Published: October 2014

In this investigation, the structural and electrical properties of nanocomposites of polyaniline (PANI) and cobalt ferrite synthesized by hydrothermal route are reported for the first time (with weight ratios of CoFe2O4/PANI 1:2 and 2:1). Synthesized nanomaterials have been characterized by XRD, FT-IR, SEM and TEM techniques. FT-IR results confirm the presence of CoFe2O4 and PANI in the samples. Their detailed conductivity measurements have been investigated. It has been found that PANI has a more effective conducting mechanism in CoFe2O4-PANI composites. These results are also consistent with the change in AC conductivity orders in composites.
The Effect of Condensation on the Morphology and Magnetic Properties of Modified Barium Hexaferrite (BaFe12O19)
Authors: Durmus Z. , Sozeri H. , Toprak M. S. , Baykal A.
Published: October 2014

We present a comparison for the effect of condensation on the morphology and magnetic properties of oleic acid modified BaFe12O19 nanoparticles. Two different samples of BaFe12O19 nanoparticles were synthesized by dehydration (Z1) and rotary evaporation (Z2) method, respectively. Oleic acid was used as the surface modification agent to observe the morphological and magnetic changes. The nanoparticles were analyzed by XRD, FTIR, TGA, SEM, and VSM techniques for structural and physicochemical characteristics. Crystallographic analysis reveals the phase as hexaferrite and the average crystallite size of Z1 and Z2 is 21±3 nm and 17±2 nm, respectively. Rotary evaporator accelerates the condensation process in viscous gel (Z2). Due to the use of rotary evaporator, the coating with oleic acid for Z2 product has been accomplished very well, as compared with Z1. As a result, saturation magnetization of Z2 sample is much lower than that of Z1 sample.
Synthesis of Multi-walled Carbon Nanotubes/ZnO Nanocomposites using Absorbent Cotton
Authors: Qu Jiao , Luo Chunqiu , Cong Qiao
Published: October 2014

This letter focuses on the synthesis of multi-walled carbon nanotubes (MWNTs) and MWNTs/ZnO nanocomposites using absorbent cotton. The MWNTs have been synthesized by a rapid heating of absorbent cotton at different temperature (400°C, 550°C, 600°C). The MWNTs/ZnO nanocomposites have been synthesized by heating mixtures of Zn(OH)2/H2O/absorbent cotton at different temperature (at about 550°C and 600°C). The X-ray diffraction (XRD) pattern and energy dispersive spectrum (EDS) clearly show that the pure MWNTs and ZnO nanocomposites (with a mean size of 35.9 nm) were synthesized. The scanning electron microscopy (SEM) images demonstrate that the structure of synthesized MWNTs was middle-hollow, with inner and outer diameter of around 10 and 80 nm. The ZnO nanocomposites that had grown on the walls of MWNTs were nonuniform and agglomerated, with an outer diameter of around 110 nm. The selected area diffraction (SAD) patterns and Raman spectrum indicate that the MWNTs were well-crystallised, and there are a few defects in the walls. Infrared absorption spectroscopy (IR) spectra suggest that the surface of MWNTs has been covered by ZnO.
Injector Quantum Dot Molecule Infrared Photodetector: A Concept for Efficient Carrier Injection
Authors: Gebhard Thomas
Published: October 2014

Quantum dot infrared photodetectors are expected to be a competitive technology at high operation temperatures in the long and very long wavelength infrared spectral range. Despite the fact that they already achieved notable success, the performance suffers from the thermionic emission of electrons from the quantum dots at elevated temperatures resulting in a decreasing responsivity. In order to provide an efficient carrier injection at high temperatures, quantum dot infrared photodetectors can be separated into two parts: an injection part and a detection part, so that each part can be separately optimized. In order to integrate such functionality into a device, a new class of quantum dot infrared photodetectors using quantum dot molecules will be introduced. In addition to a general discussion simulation results suggest a possibility to realize such adevice.
Nanoimprint Lithography: A Processing Technique for Nanofabrication Advancement
Authors: Zhou Weimin , Min Guoquan , Zhang Jing , Liu Yanbo , Wang Jinhe , Zhang Yanping , Sun Feng
Published: October 2014

Nanoimprint lithography (NIL) is an emerging micro/nano-patterning technique, which is a high-resolution, high-throughput and yet simple fabrication process. According to International Technology Roadmap for Semiconductor (ITRS), NIL has emerged as the next generation lithography candidate for the 22 nm and 16 nm technological nodes. In this paper, we present an overview of nanoimprint lithography. The classfication, research focus, critical issues, and the future of nanoimprint lithography are intensively elaborated. A pattern as small as 2.4 nm has been demonstrated. Full-wafer nanoimprint lithography has been completed on a 12-inch wafer. Recently, 12.5 nm pattern resolution through soft molecular scale nanoimprint lithography has been achieved by EV Group, a leading nanoimprint lithography technology supplier.
Effective Doping of Rare-earth Ions in Silica Gel: A Novel Approach to Design Active Electronic Devices
Authors: Haranath D. , Mishra Savvi , Joshi Amish G. , Sahai Sonal , Shanker Virendra
Published: October 2014

Eu3+ luminescence spectroscopy has been used to investigate the effective doping of alkoxide-based silica (SiO2) gels using a novel pressure-assisted sol-gel method. Our results pertaining to intense photoluminescence (PL) from gel nanospheres can be directly attributed to the high specific surface area and remarkable decrease in unsaturated dangling bonds of the gel nanospheres under pressure. An increased dehydroxylation in an autoclave resulted in enhanced red (∼611 nm) PL emission from europium and is almost ten times brighter than the SiO2 gel made at atmospheric pressure and ∼50°C using conventional Stöber-Fink-Bohn process. The presented results are entirely different from those reported earlier for SiO2:Eu3+ gel nanospheres and the origin of the enhanced PL have been discussed thoroughly.
Mg(OH)2 Nanorods Synthesized by A Facile Hydrothermal Method in the Presence of CTAB
Authors: Dhaouadi Hassouna , Chaabane Hedia , Touati Fathi
Published: October 2014

Magnesium hydroxide (Mg(OH)2) nanorods were synthesized by a simple and facile hydrothermal method in the presence of cetyltetramethylammonium bromide (CTAB) as a surfactant. Nanorods of magnesium oxide MgOwere also induced by thermal decomposition of Mg(OH)2 nanorods at 700°C, By using disk diffusion technique, the Mg(OH)2 nanorods were found to exhibit higher antibacterial efficiency against several tested bacterial strains.
Fabrication of Superhydrophobic Surfaces on Aluminum Alloy Via Electrodeposition of Copper Followed by Electrochemical Modification
Authors: Huang Ying , Sarkar D. K. , Chen X-Grant
Published: October 2014

Superhydrophobic aluminum surfaces have been prepared by means of electrodeposition of copper on aluminum surfaces, followed by electrochemical modification using stearic acid organic molecules. Scanning electron microscopy (SEM) images show that the electrodeposited copper films follow “island growth mode” in the form of microdots and their number densities increase with the rise of the negative deposition potentials. At an electrodeposition potential of −0.2 V the number density of the copper microdots are found to be 4.5×104 cm−2 that are increased to 2.9×105 cm−2 at a potential of −0.8 V. Systematically, the distances between the microdots are found to be reduced from 26.6 μm to 11.03 μm with the increase of negative electrochemical potential from −0.2V to −0.8V. X-ray diffraction (XRD) analyses have confirmed the formation of copper stearate on the stearic acid modified copper films. The roughness of the stearic acid modified electrodeposited copper films is found to increase with the increase in the density of the copper microdots. A critical copper deposition potential of −0.6V in conjunction with the stearic acid modification provides a surface roughness of 6.2 μm with a water contact angle of 157°, resulting in superhydrophobic properties on the aluminum substrates.
Effect of Gold Nanoparticles on the Photocatalytic and Photoelectrochemical Performance of Au Modified BiVO4
Authors: Long Mingce , Jiang Jingjing , Li Yan , Cao Ruqiong , Zhang Liying , Cai Weimin
Published: October 2014

An efficient visible light driven photocatalyst, gold nanoparticles (NPs) modified BiVO4 (Au/BiVO4), has been synthesized by deposition-precipitation with urea method. Au/BiVO4 exhibits enhanced photocatalytic activity for phenol degradation under λ>400 nm irradiation but negligible activity under λ>535 nm, indicating that the surface plasmon resonance (SPR) effect is too weak for organic photodegradation. According to the photoelectrochemical results of the porous powder electrodes of BiVO4 and Au/BiVO4, the SPR effect of Au NPs has been assessed. The role of Au NPs as electron sinks or sources, which is controllable by incident photon energy and applied potentials, has been discussed.
Rapid Biosynthesis of Silver Nanoparticles Using Cymbopogan Citratus (Lemongrass) and its Antimicrobial Activity
Authors: Masurkar Shalaka A. , Chaudhari Pratik R. , Shidore Vrishali B. , Kamble Suresh P.
Published: October 2014

The present study deals with the rapid green synthesis of silver nanoparticles using fresh leaves of Cymbopogan Citratus (Lemongrass). Silver nanoparticles were formed within 8∼10 minutes by microwave irradiation using aqueous solution of AgNO3 (1 mM) with fresh leaves extract of Cymbopogan Citratus. The synthesized silver nanoparticles were characterized by using UV-visible spectrophotometer analysis, nanoparticle tracking analyzer, transmission electron microscope and energy dispersive X-ray spectra. The antibacterial activity of these nanoparticles was studied against multiple drug resistant hospital isolates of E.coli, S.aureus, P.mirabilis and hospital isolates of S. typhi, K.pnuemoniae. Also, the antifungal activity of these nanoparticles was studied against C.albicans (hospital isolate) and A.niger (NCIM 616). The synergistic effect of silver nanoparticles along with antibiotics was also studied against multiple drug resistant hospital isolates and found to be effective. The extracellular synthesis of Silver nanoparticles using leaves of Cymbopogan Citratus appears to be rapid and eco-friendly.
Analysis of Nanofluids as Cutting Fluid in Grinding EN-31 Steel
Authors: Vasu V. , Kumar K. Manoj
Published: October 2014

Grinding requires high specific energy which develops high temperatures at wheel work piece interface. High temperatures impair work piece quality by inducing tensile residual stress, burn, and micro cracks. Control of grinding temperature is achieved by providing effective cooling and lubrication. Conventional flood cooling is often ineffective due to enormous heat generation and improper heat dissipation. This paper deals with an investigation on using TRIM E709 emulsifier with Al2O3 nanoparticles to reduce the heat generated at grinding zone. An experimental setup has been developed for this and detailed comparison has been done with dry, TRIM E709 emulsifier and TRIM E709 emulsifier with Al2O3 nanoparticles in grinding EN-31 steel in terms of temperature distribution and surface finish. Results shows that surface roughness and heat penetration were decreased with addition of Al2O3 nanoparticles.
A Facile Route for the Large Scale Fabrication of Graphene Oxide Papers and Their Mechanical Enhancement by Cross-linking with Glutaraldehyde
Authors: Hu Nantao , Meng Lei , Gao Rungang , Wang Yanyan , Chai Jing , Yang Zhi , Kong Eric Siu-Wai , Zhang Yafei
Published: October 2014

A facile route for the large scale production of graphene oxide (GO) papers and their mechanical enhancement has been presented in this work. The novel paper-like GO made from individual GO sheets in aqueous suspension can be achieved in large scale by a simple drop casting method on hydrophobic substrates. Significant enhancement in mechanical stiffness (341%) and fracture strength (234%) of GO paper have been achieved upon modification with a small amount (less than 10 wt%) of glutaraldehyde (GA). The cross-linking reaction takes place between hydroxyl groups on the surface of GO and aldehyde groups of GA, through forming hemiacetal structure, which can result in distinct mechanical enhancement of the GO papers.
Exact Geometric Relationships, Symmetry Breaking and Structural Stability for Single-Walled Carbon Nanotubes
Authors: Zhang Tong , Yuan Ze Shuai , Tan Li Hao
Published: October 2014

We pioneered a study about how the geometric relationship of single-walled carbon nanotubes (SWCNT) is influenced by curvature factor and non-planar geometry factor in cylindrical coordinate system based on the assumption of complete symmetry. The bond length and angle of every carbon-carbon bonds are determined by using the principle of the minimum energy. The results of the paper include:(1) From the calculation result, the symmetry breaking appears for chiral carbon nanotubes, while the part symmetry appears for achiral carbon nanotubes with increasing curvature. (2) The synergistic effect of bond lengths and bond angles is first found. (3) We conclude that the influence of non-planar geometry factor can be completely ignored on bond lengths and bond angles when the curvature parameter has been included in the model. (4) The two fractal dimensions are given from the nanoscale to the macroscale for zigzag topology and armchair topology respectively. Fractal dimensions of SWCNT show special characteristics, varying with the length of SWCNT until the lengths approach infinity. The close and inevitable correlations among curvature, symmetry breaking and stability of SWCNTs can be summed up as: the increase of curvature causes symmetry breaking, and such symmetry breaking will further reduce the structural stability.
Synthesis and Electrical Properties of Well-Ordered Layered α-MoO3 Nanosheets
Authors: Naouel R. , Dhaouadi H. , Touati F. , Gharbi N.
Published: October 2014

α-MoO3ordered nanosheets have been synthesized under hydrothermal conditions using commercial MoO3and hydroquinone as structuring agent. X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) were used to analyse the obtained material. The conductivity mechanism of the Molybdenum ordered nanosheets has been investigated using combined complex impedance and modulus formalism.

The temperature dependence of the conductivity, which was between 473 and 573 K, is very close to the Arrhenius’ law, with an activation energy of 0.76 eV. However, the conductivity of the material increases with temperature. It shows a typical negative temperature coefficient resistance (NTCR) similar to that of a semiconductor. The dielectric properties of the MoO3compound have been studied in the temperature range of 473–573 K as well as the frequency range of 10 Hz to 13 MHz. The ac-conductivity for high frequency σac(ω) obeys the universal power law.
Synthesis of Au-Cu Nano-Alloy from Monometallic Colloids by Simultaneous Pulsed Laser Targeting and Stirring
Authors: Ganjali Mansoureh , Ganjali Monireh , Khoby Soraia , Meshkot Mohammad Ali
Published: October 2014

Experimental work has been focused on the formation of alloyed Au-Cu nanoparticles under simultaneous laser exposure and mechanical stirring of mixed monometallic colloids, here referred to as dual procedure. As a feed for the dual procedure, Au and Cu monometallic nanoparticle colloids have been using a laser ablation technique. To accomplish this, bulk targets were ablated with 1064 nm wavelength Nd:YAG laser in a pure acetone (99.99%) environment. Ultraviolet-visible optical absorption spectrometry, transmission electron microscopy, X-ray diffraction and X-ray fluorescence technique have been used to characterize the nanoparticles. It has been found that experimental conditions such as stirring and laser parameters strongly affect the synthesized particle properties, including the size, shape, composition and stability of the nanoparticles. Alloy nanoparticles containing 39% Au - 61% Cu have also been prepared in the same process, but in two forms of a homogeneous alloy and a core-shell structure.
Novel Nanotrees of Crystalline Nickel formed via Electrolytic Approach
Authors: Wang Jian , Zhang Liying , Wei Liangming , Jiang Chuanhai , Zhang Yafei
Published: October 2014

Tree shaped nickel nanocrystals with long main trunk and highly ordered branches were prepared via electrolytic method in ethylene glycol solution. The morphology and structures of nanotrees of crystalline nickel can be controlled by the processing of the surfactant (PVP) and electrolytic voltage. Magnetic property measurements at room temperature indicated that the as-prepared nanotrees of crystalline nickel possess higher saturation magnetism (M

S
) and coercivity (H

C
) than that of corresponding bulk nickel materials.
Nanomaterials for Cardiac Tissue Engineering Application
Authors: Zhang Yachen , Tang Yong , Wang Ying , Zhang Liying
Published: October 2014

In recent years, the emerging cardiac tissue engineering provides a new therapeutic method for heart diseases. And in the tissue engineering, the scaffold material which can mimic the structure of the extracellular matrix properly is a key factor. The rapid expansion of nano-scaffolds during the past ten years has led to new perspectives and advances in biomedical research as well as in clinical practice. Here we search articles published in recent years extensively on cardiac tissue engineering scaffold materials and nanotechnology. And we review the traditional scaffold materials and the advances of the nano-scaffolds in cardiac tissue engineering. A thorough understanding of the nano-scaffolds would enable us to better exploit technologies to research the ideal scaffold material, and promote the cardiac tissue engineering using in the clinical practice as soon as possible.