Table of contents

In recent years the outbreak of re-emerging and emerging infectious diseases has been a significant burden on global economies and public health. The growth of population and urbanization along with poor water supply and environmental hygiene are the main reasons for the increase in outbreak of infectious pathogens. Transmission of infectious pathogens to the community has caused outbreaks of diseases such as influenza (A/H₅N₁), diarrhea (Escherichia coli), cholera (Vibrio cholera), etc throughout the world. The comprehensive treatments of environments containing infectious pathogens using advanced disinfectant nanomaterials have been proposed for prevention of the outbreaks. Among these nanomaterials, silver nanoparticles (Ag-NPs) with unique properties of high antimicrobial activity have attracted much interest from scientists and technologists to develop nanosilver-based disinfectant products. This article aims to review the synthesis routes and antimicrobial effects of Ag-NPs against various pathogens including bacteria, fungi and virus. Toxicology considerations of Ag-NPs to humans and ecology are discussed in detail. Some current applications of Ag-NPs in water-, air- and surface- disinfection are described. Finally, future prospects of Ag-NPs for treatment and prevention of currently emerging infections are discussed.

The role of disclinations in the processing, microstructure and properties of bulk nanostructured materials is reviewed. Models of grain subdivision during severe plastic deformation (SPD) based on the disclination concept, a structural model of the bulk nanostructured materials processed by SPD are presented. The critical strength of triple junction disclinations is estimated. Kinetics of relaxation of triple junction disclinations and their role in the grain boundary diffusion are studied.

In this report we present low-field magnetoresistance (LFMR) of (1 − x)La_0.7Ca_0.3MnO₃ + xLa_1.5Sr_0.5NiO₄ (x­ =0–0.3) nanocomposites at temperatures ranging from 30 to 300 K. These materials were synthesized by reactive mechanical ball milling combined with the heat treatment. Experimental results have revealed that the Curie temperature is almost independent of x, while the metal–insulator transition temperature shifts from 254 K for x = 0.0 to 65 K for x = 0.2. Particularly, the samples with x ⩾ 0.25 exhibit insulating properties. Magnetoresistance (MR) of all the samples is observed at an applied magnetic field of 3 kOe. In order to explore their MR nature at changing temperature, we analyzed carefully the obtained data basing on the phenomenological model related to the spin polarized transport (SPT) of conduction electrons at grain boundaries.

Antisense oligonucleotide to NF-κB sequence: 5'-GGA AAC ACA TCC TCC ATG-3', was microencapsulated in an albumin matrix by the method of spray drying^TM. Spectral analysis was performed on varying drug loading formulations of both drugs by mid-IR attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR). An out of plane O–H bending vibration at 948 cm⁻¹, unique to both the native and microencapsulated drugs was identified. The calculated peak areas corresponded to the drug loadings in the microsphere formulations. A standard curve could then be used to determine the drug content of an unknown microsphere formulation. Accuracy and precision were determined to be comparable to other analytical techniques such as HPLC.

The catalysts TiO₂ and TiO₂ doped with Fe and V were prepared using the sol–gel method. TiO₂-modified samples were obtained in the form of a thick film on pyrex glass sticks and tubes and were used as catalysts in the gas phase photo-oxidation of p-xylene. The physico-chemical characteristics of the catalysts were determined using the methods of Brunauer–Emmett–Teller adsorption, x-ray diffraction, and infrared, ultraviolet and visible and Raman spectroscopies. The experimental results show that the introduction of V did not expand the region of light absorption, but slightly reduced the size of the TiO₂ particles, and reduced the number of OH-groups, which should decrease the photocatalytic activity and efficiency of the obtained catalysts compared to those of pure TiO₂. The Fe-doped TiO₂ samples, in contrast, are characterized by an extension of the spectrum of photon absorption to the visible region with wavenumbers λ up to 464 nm and the values of their band gap energy decreased to lower quantities (up to 2.67 eV), therefore they should have higher catalytic activity and conversion efficiency of p-xylene in the visible region than the original sample. For these catalysts, a combined utilization of radiation by ultraviolet (λ = 365 nm) and visible (λ = 470 nm) light increased the activity and the yield in p-xylene conversion by a factor of around 2–3, as well as making these quantities more stable in comparison with those of TiO₂–P25 Degussa.

Nanostructured composite electrodes of MnO₂/C with various types of carbons (noir, mesoporous carbon and carbon vulcan) were prepared by chemical reduction. The combination of carbon vulcan and carbon nanotubes (CNTs) was also studied at the total content of 30 wt%, etc. The morphology and structure of samples were examined by scanning electron microscopy (SEM) and x-ray diffraction (XRD). The specific capacitances of the composite electrodes were determined by cyclic voltammetry measured in 2M NaCl at different potential scan rates. The carbon addition improves specific capacitance (SC) as well as specific surface area (SSA). Compared to other carbon, the highest SC value was reached at 30% content for carbon vulcan. The addition of 5 wt% CNTs in MnO₂/carbon vulcan increased the SC up to 199 F g⁻¹ and improved significantly the cycling behavior of composite electrode.

The present study demonstrates the biosynthesis of silver nanoparticles using Trichoderma koningii and evaluation of their antibacterial activity. Trichoderma koningii secretes proteins and enzymes that act as reducing and capping agent. The biosynthesized silver nanoparticles (AgNPs) were characterized by UV–Vis spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM) and x-ray diffraction (XRD). UV–Vis spectra showed absorbance peak at 413 nm corresponding to the surface plasmon resonance of silver nanoparticles. DLS was used to find out the size distribution profile. The size and morphology of the AgNPs was determined by TEM, which shows the formation of spherical nanoparticles in the size range of 8–24 nm. X-ray diffraction showed intense peaks corresponding to the crystalline silver. The antibacterial activity of biosynthesized AgNPs was evaluated by growth curve and inhibition zone and it was found that the AgNPs show potential effective antibacterial activity.

U–Mo alloys are the most promising materials fulfilling the requirements of using low enriched uranium (LEU) fuel in research reactors. From a fundamental standpoint, it is of interest to determine the basic thermodynamic properties of the cubic γ-phase U–Mo alloys. We focus our attention on the use of Mo doping together with ultrafast cooling (with high cooling rates ⩾10⁶ K s⁻¹), which helps to maintain the cubic γ-phase in U–Mo system to low temperatures and on determination of the low-temperature properties of these γ-U alloys. Using a splat cooling method it has been possible to maintain some fraction of the high-temperature γ-phase at room temperature in pure uranium. U-13 at.% Mo splat clearly exhibits the pure γ-phase structure. All the splats become superconducting with T_c in the range from 1.24 K (pure U splat) to 2.11 K (U-15 at.% Mo). The γ-phase in U–Mo alloys undergoes eutectoid decomposition to form equilibrium phases of orthorhombic α-uranium and tetragonal γ'-phase upon annealing at 500 °C, while annealing at 800 °C has stabilized the initial γ phase. The α-U easily absorbs a large amount of hydrogen (UH₃ hydride), while the cubic bcc phase does not absorb any detectable amount of hydrogen at pressures below 1 bar and at room temperature. At 80 bar, the U-15 at.% Mo splat becomes powder consisting of elongated particles of 1–2 mm, revealing amorphous state.

Phyllanthus amarus (P. amarus) is commonly used for traditional Indian medicine and as dietary adjuncts for the treatment of numerous physiological disorders including hepatic disorders. Due to the poor water solubility of its major constituents such as lignans and flavonoids, its absorption upon oral administration could be limited. The present study was designed to evaluate and compare the hepatoprotective effects of the ethanolic extract of P. amarus (PAE) and its nanoparticles (PAN) on paracetamol induced acute liver toxicity in Sprague–Dawley rats. An oral dose of PAE at 125 and 250 mg kg⁻¹ and PAN at 25 and 50 mg kg⁻¹ showed a significant hepatoprotective effect relatively to the same extent (P < 0.001) by reducing levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and bile salts. These biochemical assessments were supported by rat hepatic biopsy examinations. Moreover, the results also indicated that the hepatoprotective effect of 50 mg kg⁻¹ PAN was effectively better than 125 mg kg⁻¹ PAE (P < 0.001), and an oral dose of PAN that is five times less than PAE could exhibit similar levels of outcomes. In conclusion, we suggest that the nanoparticles system can be applied to overcome other poorly water soluble herbal medicines and furthermore to decrease the treatment dosage.

Nano-sized platinum electrocatalysts on a carbon support (Pt/C) have been synthesized by the polyol reduction method under microwave irradiation using ethylene glycol (EG) as the reductant and carbon vulcan XC-72R as the support material. The physical characteristics of the Pt/C materials were analyzed using transmission electron microscopy and Brunauer–Emmet–Teller nitrogen adsorption theory. The glycerol and EG electro-oxidation in alkaline media on the Pt/C catalysts was investigated with cyclic voltammetry and chronoamperometry. The particle size of Pt on carbon was about 3.0 nm. The catalytic activity for the alcohol electro-oxidation of Pt/C materials synthesized in various pH values (7.9–9.5) was found to be significantly higher than that of commercial Pt/C (Aldrich Sigma, 10 wt% Pt/activated carbon). The Pt/C catalyst synthesized in pH 9.5 showed the best electrochemical behavior. At all the synthesized Pt/C electrodes, compared with glycerol, the oxidation rate of EG was about ten times higher.

We investigated sandwich structure of the conventional absorber metamaterials to expand the study on dual-band absorption in our previous work (2013 Appl. Phys. Lett.102 081122). The advantages of the artificial structuring of plasmonic resonators or 'meta-atoms' were exploited to gradually enhance/degrade the absorption peaks by polarization angle of electromagnetic wave. By reshaping the rings at the font of slab, dual- or single-peak absorption is controlled. The absorber is demonstrated in the GHz region.

Rutile TiO₂ was synthesized by sol–gel method. Vanadium-doped rutile TiO₂ nanoparticle was obtained by reactive grinding method. The photocatalytic activity was evaluated by the degradation of methylene blue (MB) under solar light at room temperature. The results show that after 4 h of milling the particle size of rutile decreased from 130 to 14 nm and the Brunauer–Emmet–Teller (BET) specific surface area increased from 7.18 to 15.12 m² g⁻¹. The vanadium doping promoted the particle growth and the particle size of vanadium-modified rutile TiO₂ obtained by 4 h of milling is about 22 nm, but the BET specific surface area increased from 15.12 m² g⁻¹ for TiO₂ to 20.8 m² g⁻¹ for vanadium-doped TiO₂ under the same conditions. The 5% vanadium-doped rutile possessed better absorption ability of solar light; the calculated band gap energy value is 2.7 eV. The degradation rate of MB on vanadium-doped rutile TiO₂ was higher than that of pure rutile obtained after the same time of milling.

Carbon-supported Pt catalysts in nano-size for proton exchange membrane fuel cell (PEMFC) were synthesized by electroless deposition method with and without using ethylene glycol (EG) and NaBH₄ as reductant. Scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), and transmission electron microscopy (TEM) methods were used to determine the content, size and the distribution of Pt particles on carbon Vulcan XC-72. The cyclic voltammetry (CV) measurements were used to evaluate the activity and durability of catalyst. A comparison of physical and electrochemical characterizations was carried out on three types of catalysts: Pt catalyst of 20 wt% on Vulcan XC-72 prepared by electroless deposition method with and without EG and commercial catalyst purchased from Fuel Cell Earth LLC (USA). The results showed that with the presence of EG, the size of synthesized Pt particles was around 2–3 nm, in comparison with 4–16 nm in the case without EG and 3–4 nm of commercial catalyst. The CV results expressed that catalysts prepared with EG have the highest activity and durability.

Graphene films were successfully synthesized by atmospheric pressure chemical vapor deposition (APCVD) method. Methane (CH₄) gas and copper (Cu) tapes were used as a carbon source and a catalyst, respectively. The CVD temperature and time were in the range of 800–1000 °C and 10 s to 45 min, respectively. The role of the CVD temperature and time on the growth of graphene films was investigated in detail via scanning electron microscopy (SEM) and Raman spectroscopy techniques. The results of SEM images and Raman spectra show that the quality of the graphene films was improved with increasing of CVD temperature due to the increase of catalytic activity.

Anodic aluminum oxide (AAO) nano-templates are used in many fields of nanotechnology, particularly for use in creation of nanowires and nanotubes. In this research, the method for fabricating AAO nano-templates in two different electrolyte solutions (sulfuric acid and oxalic acid) via two step anodization procedure is presented. The influence of parameters related to both anodization steps such as the electrolyte, solution temperature, voltage and time on the pore size, porous distance and pore density was investigated. Scanning electron microscopy (SEM) images of the nano-templates also pointed out the effectiveness of this anodization method. The synthesis of carbon nanostructures from a polymeric precursor such as epoxy via fully filling the nanoporous AAO templates is reported. The prepared nanowires and nanotubes have been characterized by transmission electron microscopy (TEM), Raman spectroscopy and SEM. The results show the typical morphology and properties of multiwall carbon nanotubes and other nanostructures.

In this paper, the synthesis of hydroxyapatite (HAp) nanopowder was studied by chemical precipitation method at different values of reaction temperature, settling time, Ca/P ratio, calcination temperature, (NH₄)₂HPO₄ addition rate, initial concentration of Ca(NO₃)₂ and (NH₄)₂HPO₄. Analysis results of properties, morphology, structure of HAp powder from infrared (IR) spectra, x-ray diffraction (XRD), energy dispersive x-ray (EDX) spectra and scanning electron microscopy (SEM) indicated that the synthesized HAp powder had cylinder crystal shape with size less than 100 nm, single-phase structure. The variation of the synthesis conditions did not affect the morphology but affected the size of HAp crystals.

Zinc oxide nanoparticles (ZnO NPs) have attracted great attention because of their superior optical properties and wide application in biomedical science. However, little is known about the anticandidal activity of ZnO NPs against Candida albicans (C. albicans). This study was designed to develop the green approach to synthesize ZnO NPs using egg white (denoted as EtZnO NPs) and investigated its possible mechanism of antimicrobial activity against C. albicans 077. It was also notable that anticandidal activity of EtZnO NPs is correlated with reactive oxygen species (ROS) production in a dose dependent manner. Protection of histidine against ROS clearly suggests the implication of ROS in anticandidal activity of EtZnO NPs. This green approach based on egg white-mediated synthesis of ZnO NPs paves the way for developing cost effective, eco-friendly and promising antimicrobial nanomaterial for applications in medicine.

In this study a metal-organic framework (MOF-199) has been synthesized by solvent-thermal method. The conditions of preparation and activation processes have been investigated. The obtained material was characterized by methods of x-ray diffraction (XRD), infrared (IR) spectroscopy, thermogravimatric analysis (TGA) and scanning electron microscopy (SEM). The CO₂ adsorption measurements were carried out on a high pressure volumetric analyzer (Micromeritics HPVA − 100). According to experimental results, Cu(NO₃)₂·3H₂O has been shown to be the best copper(II) precursor for the synthesis of MOF-199 and N,N-dimethylformamide (DMF):C₂H₅OH:H₂O with the ratio of 1:1:1 has been chosen as the most suitable solvent. The appropriate activation condition has been determined as follows: activate at 200 °C for 5 h and use CH₃OH as the solvent to remove DMF. At the optimal conditions, an octahedral shape and three-dimensional (3D) structure of crystallite of MOF-199 was obtained. The synthesized MOF-199 expressed a high value of specific surface area (1448 m² g⁻¹ by Brunauer–Emmet–Teller (BET) method and 2028 m² g⁻¹ by Langmuir method) with Ta porous size of crystal of 11.8 Å and specific volume of 0.693 cm³ g⁻¹; it was still stable up to 332 °C and its CO₂ storage capacity reached to 206.59 cm³ (STP) g⁻¹ at 25.76 bar.

In this work the surface modification and functionalization of carbon nanotubes (CNTs) were investigated. CNTs were firstly treated by acid mixture H₂SO₄/HNO₃ to introduce the carboxylic group onto the surface of CNTs. This carboxylic group was used as reaction precursor in the functionalization. Two functional groups, dodecylamine (DDA) and 3-aminopropyl triethoxysilane (3-APTES), were successfully covalently attached to CNTs. The functionalized CNTs were characterized by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, differential scanning calorimetry and thermal gravimetric analysis (DSC/TGA) and transmission electron microscopy (TEM) methods. The CNTs attached to the organofunctional moieties have greater versatility for further utilization in different application fields such as biology, nanocomposites, solar energy, etc.

A series of alumina-supported Co–Mo samples prepared by the wet impregnation method have been used as catalysts for the synthesis of single-walled carbon nanotubes (SWNTs) by chemical vapor deposition (CVD) using CH₄ at 900 °C. The mass ratio of the bimetallic catalyst with a composition of Co:Mo:Al₂O₃ has been demonstrated to play an important role in the formation of the single-walled carbon nanotubes obtained. In addition, the selection of solvent to disperse the Co–Mo/Al₂O₃ catalysts has a significant effect on the resulting quality of the carbon nanotubes produced.