Multiplexed dot immunoassay using Ag nanocubes,Au/Ag alloy nanoparticles,and Au/Ag nanocages

We report the first application of Ag nanocubes, Au/Ag alloy nanoparticles, and Au/Ag nanocages in a multiplexed dot immunoassay. The assay principle is based on the staining of analyte drops on a nitrocellulose membrane strip by using multicolor nanoparticles conjugated with biospecific probing molecules. Nanoparticles were prepared by a galvanic replacement reaction between the Ag atoms of silver nanocubes and Au ions of tetrachloroauric acid. Depending on the Ag/Au conversion ratio, the particle plasmon resonance was tuned from 450 to 700 nm and the suspension color changed from yellow to blue. The particles of yellow, red, and blue suspensions were functionalized with chicken, rat, and mouse immuno gamma globulin (IgG) molecular probes, respectively. The multiplex capability of the assay was illustrated by a proof-of-concept experiment involving simultaneous one-step determination of target molecules (rabbit anti-chicken, anti-rat, and anti-mouse antibodies) with a mixture of fabricated conjugates. Under naked eye examination, no cross-colored spots or nonspecific bioconjugate adsorption were observed, and the low detection limit was about 20 fmol.      

Reversible Switching of Block Copolymer Nanopatterns by Orthogonal Electric Fields

It is demonstrated that the orientation of striped patterns can be reversibly switched between two perpendicular in‐plane orientations upon exposure to electric fields. The results on thin films of symmetric polystyrene‐block‐poly(2‐vinyl pyridine) polymer in the intermediate segregation regime disclose two types of reorientation mechanisms from perpendicular to parallel relative to the electric field orientation. Domains orient via grain rotation and via formation of defects such as stretched undulations and temporal phase transitions. The contribution of additional fields to the structural evolution is also addressed to elucidate the generality of the observed phenomena. In particular solvent effects are considered. This study reveals the stabilization of the meta‐stable in‐plane oriented lamella due to sequential swelling and quenching of the film. Further, the reorientation behavior of lamella domains blended with selective nanoparticles is addressed, which affect the interfacial tensions of the blocks and hence introduce another internal field to the studied system. Switching the orientation of aligned block copolymer patterns between two orthogonal directions may open new applications of nanomaterials as switchable electric nanowires or optical gratings.     

Hard Alloy WC–24% Ni Obtained in the Solid Phase from Ultrafine WC,NiO, and C Powders. Part 2. Mechanical Properties

Mechanical properties of WC–24 mass% Ni alloy prepared by a combination in single stage of metal phase synthesis and compaction of an ultrafine mixture of WC–Ni powders by high-energy compaction and sintering are studied. Tungsten carbide, nickel oxide, and carbon are selected as the starting powders. After milling the initial powders the average particle size is 200-300 nm. Previously compacted briquettes of WC + NiO + C are heated, sintered, and pressed in the range 950-1300°C at vacuum of 0.133 Pa. Briquettes are also sintered in the liquid phase at 1350°C for comparison. Ultimate strength in bending, fracture toughness, ultimate strength in compression, and Vickers hardness are determined for specimens prepared at different temperatures. The dependence of mechanical properties on specimen consolidation temperature is studied. It is shown that these dependences for pressed specimens have a maximum at 1200-1250°C. The high level of properties (ultimate strength in bending 2500 MPa, ultimate strength in compression 3100 MPa, fracture toughness 19 MPa·m^1/2, and hardness 10.0 GPa) are achieved for a WC + Ni + C powder mixture to which carbon is added in the form of a liquid carbon-containing compound. Introduction into the mixture of commercial carbon grade P803 leads to low specimen mechanical properties. The effect on mechanical properties of porosity and pore size, and also grain boundary quality between particles is studied.     

Hard Alloy WC – 24% Ni Obtained in the Solid Phase from Ultrafine WC, NiO, and C Powders. Part 1. Density and Structure of Specimens

We have studied the density and structure of specimens of the alloy WC – 24 mass% Ni, obtained by combining into one step the processes of synthesis of the metallic phase and compaction of the ultrafine mixture of WC – Ni powders by high-energy pressing and sintering. We have established that reduction of nickel monoxide by carbon occurs at temperatures of 650-750°C and does not affect the shrinkage process which in the case of sintering begins only at a temperature of 1050°C. High-energy pressing of briquettes sintered at the indicated temperature reduces their porosity from 30-25% down to 8-4%. Specimens of porosity <1% can be obtained by pressing at 1150°C or 1050°C in the case of triple pressing. Raising the temperature at which the briquettes are heated is accompanied by enlargement of the pores together with a decrease in the total porosity, but at temperatures of 1300°C (sintering) and 1250°C (pressing), the pore dimensions are sharply reduced. The high density of the specimens pressed at low temperature does not provide low electrical resistance, which suggests the presence of weakly connected boundaries. When the specimens are sintered and pressed in the solid phase, we observe the growth of tungsten carbide particles. It is most rapid at 1150-1250°C, while at 1050°C the particle growth process slows down. Reduction of the metal oxide when the powders are heated promotes formation of structure in the higher temperature range.     

Phosphorylation but Not Oligomerization Drives the Accumulation of Tau with Nucleoporin Nup98

Tau is a neuronal protein that stabilizes axonal microtubules (MTs) in the central nervous system. In Alzheimer’s disease (AD) and other tauopathies, phosphorylated Tau accumulates in intracellular aggregates, a pathological hallmark of these diseases. However, the chronological order of pathological changes in Tau prior to its cytosolic aggregation remains unresolved. These include its phosphorylation and detachment from MTs, mislocalization into the somatodendritic compartment, and oligomerization in the cytosol. Recently, we showed that Tau can interact with phenylalanine-glycine (FG)-rich nucleoporins (Nups), including Nup98, that form a diffusion barrier inside nuclear pore complexes (NPCs), leading to defects in nucleocytoplasmic transport. Here, we used surface plasmon resonance (SPR) and bio-layer interferometry (BLI) to investigate the molecular details of Tau:Nup98 interactions and determined how Tau phosphorylation and oligomerization impact the interactions. Importantly, phosphorylation, but not acetylation, strongly facilitates the accumulation of Tau with Nup98. Oligomerization, however, seems to inhibit Tau:Nup98 interactions, suggesting that Tau-FG Nup interactions occur prior to oligomerization. Overall, these results provide fundamental insights into the molecular mechanisms of Tau-FG Nup interactions within NPCs, which might explain how stress-and disease-associated posttranslational modifications (PTMs) may lead to Tau-induced nucleocytoplasmic transport (NCT) failure. Intervention strategies that could rescue Tau-induced NCT failure in AD and tauopathies will be further discussed.     

Metabolomics as a Tool to Elucidate the Sensory,Nutritional and Safety Quality of Wheat Bread—A Review

Wheat (Triticum aestivum) is one of the most extensively cultivated and used staple crops in human nutrition, while wheat bread is annually consumed in more than nine billion kilograms over the world. Consumers’ purchase decisions on wheat bread are largely influenced by its nutritional and sensorial characteristics. In the last decades, metabolomics is considered an effective tool for elucidating the information on metabolites; however, the deep investigations on metabolites still remain a difficult and longtime action. This review gives emphasis on the achievements in wheat bread metabolomics by highlighting targeted and untargeted analyses used in this field. The metabolomics approaches are discussed in terms of quality, processing and safety of wheat and bread, while the molecular mechanisms involved in the sensorial and nutritional characteristics of wheat bread are pointed out. These aspects are of crucial importance in the context of new consumers’ demands on healthy bakery products rich in bioactive compounds but, equally, with good sensorial acceptance. Moreover, metabolomics is a potential tool for assessing the changes in nutrient composition from breeding to processing, while monitoring and understanding the transformations of metabolites with bioactive properties, as well as the formation of compounds like toxins during wheat storage.     

The Robot Scientist Adam

Despite science's great intellectual prestige, developing robot scientists will probably be simpler than developing general AI systems because there is no essential need to take into account the social milieu.     

Binding of aroma compounds with legumin. III. Thermodynamics of competitive binding of aroma compounds with 11S globulin depending on the structure of aroma compounds

This paper considers the prominent features in competitive binding of aroma esters from their mixtures to 11S globulin of broad beans (legumin) in aqueous medium at pH 7.2 and ionic strength of 0.05 mol dm⁻³. Series of alkyl acetates (C₄–C₈) and methyl esters of carbonic acids (C₅–C₉), differing in the length of hydrocarbon chain, have been under our studying. To accomplish the ends of the study, a combination of ultrafiltration and gas–liquid chromatography (GC) has been used. An increase in the length of hydrocarbon chain of the aroma esters brought about greater binding affinity for the protein, the occurrence of some structural restrictions in the interior of the protein molecule, preventing binding, and the change in the binding mechanism of the aroma compounds at the specific critical length of hydrocarbon chain. Differential scanning microcalorimetry data suggested that the revealed changes in the binding mechanism of the studied aroma compounds were attributable to the conformational modification of the protein globule as a result of binding with the aroma compounds. A distinguishing feature in binding of methyl esters of carbonic acids with legumin was their greater binding affinity for the protein as compared with alkyl acetates. The mutual effect of aroma compounds on binding from their equimolar mixtures to the protein made itself evident, firstly, as a drastic increase in the binding extent of aroma esters, having rather long hydrocarbon chain and, secondly, as a dramatic change in the binding mechanism of the aroma esters with relatively short hydrocarbon chain.     

A new wave of innovations in psychology: High intellectual and creative educational multimedia technologies.

This article describes high intellectual and creative educational multimedia technologies (HICEMTs), which will constitute one of the innovative breakthroughs in science and technology of the 21st century and will lead to a new wave of innovations in psychology. HICEMTs appear at the intersection of many subdisciplines of psychology (including general, cognitive, developmental, educational, personality, media, cyber, and applied), education, and multimedia. The general and specific nature of HICEMTs is considered. The importance of HICEMTs is discussed from technological, economic, societal, educational, and psychological perspectives. (PsycINFO Database Record (c) 2010 APA, all rights reserved)