Alternative Local Melting-Solidification of Suspended Nanoparticles for Heterostructure Formation Enabled by Pulsed Laser Irradiation

Phase formation by pulsed laser irradiation of suspended nanoparticles has recently been introduced as a promising synthesis technique for heterostructures. The main challenge still lingers regarding the exact mechanism of particle formation due to the non-equilibrium kinetic by-products resulting from the localized alternative, fast, high-temperature nature of the process. Here, the authors analyze the bond breaking/formation of copper or copper (II) interfaces with ethanol during the absorption of pulses for Cu-CuO-Cu₂O formation applicable as an electrocatalyst in ethanol oxidation fuel cells. This study includes but is not limited to, a comprehensive discussion of the interaction between nano-laser pulses and suspension for practical control of the synthesis process. The observed exponential and logarithmic changes in the content of heterostructures for the CuO-ethanol and Cu-ethanol samples irradiated with different fluences are interpreted as the dominant role of physical and chemical reactions, respectively, during the pulsed laser irradiation of suspensions synthesis. It is also shown that the local interface between dissociated ethanol and the molten sphere is responsible for the oxidative/reductive interactions resulting in the formation of catalytic-augmented Cu³⁺ by-product, thanks to the reactive bond force field molecular dynamics studies confirmed by ab-initio calculations and experimental observations.     

Synthesis of protein nano-conjugates for cancer therapy

A eukaryotic cell contains thousands of proteins that regulate its cellular function; delivering functional proteins into cells to rectify cellular functions holds great promise for treatment of various diseases, especially cancers. In this context, ribonuclease (RNase), an enzyme that breaks down ribonucleic acid (RNA), has great potential for cancer therapy. However, its therapeutic application is hampered by poor intracellular delivery efficiency and inhibition by ubiquitous intracellular RNase inhibitors. In this work, by designing and synthesizing RNase nano-conjugates by in situ atom transfer radical polymerization (ATRP), we demonstrate a simple solution to address both challenges. Compared with native RNase, nano-conjugates exhibit significantly enhanced intracellular delivery efficiency, inhibitor resistance, and a near five-fold increase in cytotoxicity. This work provides a novel platform for delivery of therapeutic proteins for cancer therapy and other applications.     

A parallel solution to the HIP game based on genetic algorithms

In this piece of research, genetic algorithms are put forward for solving the HIP game. The proposed parallel approach manipulates candidate solutions via mutation and selection; no crossover has been employed. The population is limited to one candidate solution per generation, thus keeping the computational complexity of the approach to a minimum. It is shown that the proposed approach is superior to the approaches reported in the literature: Solutions are more speedily provided, whereas the frequency of finding a solution is significantly higher; furthermore, considerably more complex instances of the HIP game are successfully solved. © 2009 Wiley Periodicals, Inc.     

Synthesis,characterization and antibacterial activity studies of poly-{styrene-acrylic acid} with silver nanoparticles

This work reports the preparation and characterization of copolymer poly-{styrene-acrylic acid} with monomeric ratio of styrene/acrylic acid of 9:1 using benzoyl peroxide as initiator and furthermore filled with nanosilver (25 ppm and 50 ppm) in water/acetone (1:40 v/v). The nanosilver emulsion was obtained from chemical reduction using NaBH₄ as reducing agent and sodium citrate as the stabilizer. The preparation of nanosilver emulsion was monitored by the appearance of a Plasmon Resonant Absorption band in a UV–visible spectrophotometer and the particles sizes were observed through TEM. Microbiological studies were performed to investigate the antimicrobial activity of this new material against the microorganisms Escherichia coli (ATCC-25922) and Staphylococcus aureus (ATCC-6538), used as reference strains. The antimicrobial activity of the poly-{styrene-acrylic acid} filled with nanosilver was confirmed by the presence of an inhibition halo of the bacterial growth in seeded culture media, but was not found with the poly(styrene-acrylic acid) alone. The present work suggests that silver ions are released from the polymeric matrix to the culture media and have the ability to tune the Ag⁺ ions released by controlling the amount of Ag nanoparticles embedded in the composite.     

Structural and morphological investigation of magnetic nanoparticles based on iron oxides for biomedical applications

The present work reports the synthesis, characterization and properties of magnetic iron oxide nanoparticles for biomedical applications, correlating the nanoscale tunabilities in terms of size, structure, and magnetism. Magnetic nanoparticles in different conditions were prepared through thermal decomposition of Fe(acac)₃ in the presence of 1,2 hexadecanodiol (reducing agent) and oleic acid and oleylamine (ligands) in a hot organic solvent. The 2,3-dimercaptosuccinic acid (DMSA) was exchanged onto the nanocrystal surface making the particles stable in water. Nanoparticles were characterized by X-ray diffraction (XRD) measurements, small angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). Preliminary tests of incorporation of these nanoparticles in cells and their magnetic resonance image (MRI) were also carried out. The magnetization characterizations were made by isothermal magnetic measurements.     

Non-visual game design and training in gameplay skill acquisition – A puzzle game case study

This paper reports the results of a study on the design and evaluation of the game and techniques which allow puzzles to be played in the absence of visual feedback. We have demonstrated that a camera-mouse can be used successfully for blind navigation and target location acquisition within a game field. To gradually teach the players the sequential learning method was applied. Blind exploration of the gamespace was augmented with sticky labels and overview sound cues, verbal and non-verbal, which can significantly reduce the cognitive load and facilitate mental matching and integration. The full-sticky labels technique does not require fine motor skills and allows a user to gain control over the game with a minimum level of skills. With the vertical sticky labels technique training was focused on the development of accurate head movements only on a horizontal plane. With practice, the players can use the non-sticky labels technique. After 240 trials (3–4 h), the cumulative experience of the blindfolded players was increased 22.5–27 times compared to the initial 10 trials.     

SBA-15 modified with Al,Ti, or Zr as supports for highly active NiW catalysts for HDS

A series of SBA-15-type materials modified with Al, Ti, and Zr were prepared and used as supports for hydrodesulfurization (HDS) catalysts based on NiW. Prepared supports and catalysts were characterized by N₂ physisorption, small- and wide-angle XRD, UV–Vis DRS, FT-IR, IEP, TPR, TPD, HRTEM, and SEM–EDX. Sulfided catalysts were evaluated in HDS of dibenzothiophene (DBT). Catalytic activity tests show that the creation of defined anchoring points for the W species by modifying the surface of SBA-15 with Al, Ti, and Zr results in a considerable improvement in catalysts’ performance compared to pure SBA-supported analog. The possible reasons for this behavior are discussed.     

A general regression artificial neural network for two-phase flow regime identification

Supplementing the collection of artificial neural network methodologies devised for monitoring energy producing installations, a general regression artificial neural network is proposed for the identification of the two-phase flow that occurs in the coolant channels of boiling water reactors. The utilization of a limited number of image features derived from radiography images affords the proposed approach with efficiency and non-invasiveness. Additionally, the application of counter-clustering to the input patterns prior to training accomplishes an 80% reduction in network size as well as in training and test time. Cross-validation tests confirm accurate on-line flow regime identification.