Anatomical correlates of the functional organization in the human occipitotemporal cortex

The connectivity between functionally distinct areas in the human brain is unknown because of the limitations posed by current postmortem anatomical labeling techniques. Diffusion tensor imaging (DTI) has previously been used to define large white matter tracts based on well-known anatomical landmarks in the living human brain. In the present study, we used DTI coupled with functional magnetic resonance imaging (fMRI) to assess neuronal connections between human striate and functionally defined extrastriate ventral cortical areas. Functional areas were identified with conventional fMRI mapping procedures and then used as seeding points in a DTI analysis to ascertain connectivity patterns between cortical areas, thus yielding the pattern of connections between human occipitoventral visual areas in vivo.     

Experimental study of the dynamics of magneto-rheological fluid droplet impact

The kinematics of a magneto-rheological fluid droplet impact on a smooth surface, subjected to external magnetic field, was studied theoretically and experimentally. A time-dependent one-dimensional model of the impact, as typified by the droplet top center point height kinematics is developed. A series of experiments were conducted in order to validate the theoretical model. The shape changes generated during the impact process were recorded using a digital high-speed camera. Our novel kinematical model based on a variable damping function shows very good agreement with the experimental data for a wide range of Mason and Reynolds numbers.     

Laser desorption ionization of small molecules assisted by tungsten oxide and rhenium oxide particles

Inorganic metal oxides have shown potential as matrices for assisting in laser desorption ionization with advantages over the aromatic acids typically used. Rhenium and tungsten oxides are attractive options due to their high work functions and relative chemical inertness. In this work, it is shown that ReO₃ and WO₃, in microparticle (μP) powder forms, can efficiently facilitate ionization of various types of small molecules and provide minimized background contamination at analyte concentrations below 1 ng/µL. This study shows that untreated inorganic WO₃ and ReO₃ particles are valid matrix options for detection of protonatable, radical, and precharged species under laser desorption ionization. Qualitatively, the WO₃ μP showed improved detection of apigenin, sodiated glucose, and precharged analyte choline, while the ReO₃ μP allowed better detection of protonated cocaine, quinuclidine, ametryn, and radical ions of polyaromatic hydrocarbons at detection levels as low as 50 pg/µL. For thermometer ion survival yield experiments, it was also shown that the ReO₃ powder was significantly softer than α‐cyano‐4‐hydroxycinnaminic acid. Furthermore, it provided higher intensities of cocaine and polyaromatic hydrocarbons, at laser flux values equal to those used with α‐cyano‐4‐hydroxycinnaminic acid. Copyright © 2015 John Wiley & Sons, Ltd.     

Selective Inhibition of Aggregation and Toxicity of a Tau‐Derived Peptide using Its Glycosylated Analogues

Protein glycosylation is a ubiquitous post‐translational modification that regulates the folding and function of many proteins. Misfolding of protein monomers and their toxic aggregation are the hallmark of many prevalent diseases. Thus, understanding the role of glycans in protein aggregation is highly important and could contribute both to unraveling the pathology of protein misfolding diseases as well as providing a means for modifying their course for therapeutic purposes. Using β‐O‐linked glycosylated variants of the highly studied Tau‐derived hexapeptide motif VQIVYK, which served as a simplified amyloid model, we demonstrate that amyloid formation and toxicity can be strongly attenuated by a glycan unit, depending on the nature of the glycan itself. Importantly, we show for the first time that not only do glycans hinder self‐aggregation, but the glycosylated peptides are capable of inhibiting aggregation of the non‐modified corresponding amyloid scaffold.     

Irradiation of germanium nanocrystals with reactor neutrons

The effect of reactor neutron irradiation on the structure of germanium nanocrystals ion-implanted into an amorphous silicon dioxide film was studied using laser Raman scattering, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The sample irradiation with a high dose of fast reactor neutrons resulted in lattice destruction and amorphization of a part of nanocrystals, leaving off a significant part well retained. Thus indicating that this nano-based material may have potential for the fabrication of devices operating under extreme conditions. Radiation defect annealing and full restoration of the nanocrystal structure were observed at 800°C; however, the average size of nanocrystals and their spatial distribution were changed.     

Sonochemical coating of paper by microbiocidal silver nanoparticles

Colloidal silver has gained wide acceptance as an antimicrobial agent, and various substrates coated with nanosilver such as fabrics, plastics, and metal have been shown to develop antimicrobial properties. Here, a simple method to develop coating of colloidal silver on paper using ultrasonic radiation is presented, and the coatings are characterized using X-ray diffraction (XRD), high resolution scanning electron microscope (HRSEM), and thermogravimetry (TGA) measurements. Depending on the variables such as precursor concentrations and ultrasonication time, uniform coatings ranging from 90 to 150 nm in thickness have been achieved. Focused ion beam (FIB) cross section imaging measurements revealed that silver nanoparticles penetrated the paper surface to a depth of more than 1 μm, resulting in highly stable coatings. The coated paper demonstrated antibacterial activity against E. coli and S. aureus, suggesting its potential application as a food packing material for longer shelf life.     

Lithographically-defined 3D porous networks as active substrates for surface enhanced Raman scattering

Interferometric lithographically fabricated porous carbon acts as active substrates for Surface Enhanced Raman Scattering (SERS) applications with enhancement factors ranging from 7 to 9 orders of magnitude.     

Low Mass MS/MS Fragments of Protonated Amino Acids Used for Distinction of Their 13C- Isotopomers in Metabolic Studies

Glu, Gln, Pro, and Ala are the main amino acids involved in ammonia detoxification in mosquitoes. In order to develop a tandem mass spectrometry method (MS²) to monitor each carbon of the above isotopically-labeled ¹³C-amino acids for metabolic studies, the compositions and origins of atoms in fragments of the protonated amino acid should be first elucidated. Thus, various electrospray (ESI)-based MS² tools were employed to study the fragmentation of these unlabeled and isotopically-labeled amino acids and better understand their dissociation pathways. A broad range of fragments, including previously-undescribed low m/z fragments was revealed. The formulae of the fragments (from m/z 130 down to m/z 27) were confirmed by their accurate masses. The structures and conformations of the larger fragments of Glu were also explored by ion mobility mass spectrometry (IM-MS) and gas-phase hydrogen/deuterium exchange (HDX) experiments. It was found that some low m/z fragments (m/z 27–30) are common to Glu, Gln, Pro, and Ala. The origins of carbons in these small fragments are discussed and additional collision induced dissociation (CID) MS² fragmentation pathways are proposed for them. It was also found that small fragments (≤m/z 84) of protonated, methylated Glu, and methylated Gln are the same as those of the underivatized Glu and Gln. Taken together, the new approach of utilizing low m/z fragments can be applied to distinguish, identify, and quantify ¹³C-amino acids labeled at various positions, either in the backbone or side chain.      

Microcantilevers as gas‐phase sensing platforms: Simplification and optimization of the production of polymer coated porous‐silicon‐over‐silicon microcantilevers

The asymmetric roughening of silicon microcantilevers using different vapor stain‐etching conditions is studied with the aim of optimizing face selective coating of microcantilevers by polymers through simple dipping. The effect of roughening is studied by following the time‐dependent guest‐induced bending of silicone microcantilevers coated with a poly‐4‐vinylpyridine sensing layer. A correlation between the surface roughness of the microcantilevers and their time‐dependent guest‐induced bending is gained from combining high resolution scanning electron microscopy studies of the surface of the microcantilevers as well as their cross‐sections with time‐dependent guest‐induced microcantilever bending. The purpose of the present work is to lay the foundations for a small and relatively simple gas‐phase sensing tool based on a microcantilever platform capable of offering wide range sensing capabilities. © 2013 Wiley Periodicals, 2014 , 52, 141–146