Mindlessness–mindfulness in perspective: A reply to Valerie Folkes.

Responds to V. S. Folkes's (see record 1985-20109-001) critique of the present authors' (see record 1979-23568-001) analysis of the mindlessness of Ss' actions in complying with confederates' requests. Discussion focuses on Folkes's assertion that differential rates of compliance reflect the controllability of the reasons provided and her claim that the present authors' Ss were cognitively active. It is argued that there is nothing in Folkes's results to contradict the idea that people are sometimes mindful and sometimes not. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decision-tree instance-space decomposition with grouped gain-ratio

This paper examines a decision-tree framework for instance-space decomposition. According to the framework, the original instance-space is hierarchically partitioned into multiple subspaces and a distinct classifier is assigned to each subspace. Subsequently, an unlabeled, previously-unseen instance is classified by employing the classifier that was assigned to the subspace to which the instance belongs. After describing the framework, the paper suggests a novel splitting-rule for the framework and presents an experimental study, which was conducted, to compare various implementations of the framework. The study indicates that using the novel splitting-rule, previously presented implementations of the framework, can be improved in terms of accuracy and computation time.     

Y-junction bamboo-like CN<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> nanotubes

The method for the production of multiwall Y-junction bamboo-like CN _x nanotubes by the resistive heating of graphite is described. Different branched bamboo-like CN _x nanotubes have been observed. The possible mechanism of the formation of branched nanotubes is proposed.     

I-motif nanospheres: unusual self-assembly of long cytosine strands

The synthesis and characterization of novel DNA structures based on tetraplex cytosine (C) arrangements, known as i-motifs or i-tetraplexes, is reported. Atomic force microscopy (AFM) investigation shows that long C-strands in mild acidic conditions form compact spherically shaped nanostructures. The DNA nanospheres are characterized by a typical uniform shape and narrow height distribution. Electrostatic force microscopy (EFM) measurements performed on the i-motif spheres clearly show their electrical polarizability. Further investigations by scanning tunneling microscopy (STM) at ultrahigh vacuum reveals that the structures exhibit an average voltage gap of 1.9 eV, which is narrower than the voltage gap previously measured for poly(dG)-poly(dC) molecules in similar conditions.     

Optical nanomanipulations of malignant cells: controlled cell damage and fusion

Specifically targeting and manipulating living cells is a key challenge in biomedicine and in cancer research in particular. Several studies have shown that nanoparticles irradiated by intense lasers are capable of conveying damage to nearby cells for various therapeutic and biological applications. In this work ultrashort laser pulses and gold nanospheres are used for the generation of localized, nanometric disruptions on the membranes of specifically targeted cells. The high structural stability of the nanospheres and the resonance pulse irradiation allow effective means for controlling the induced nanometric effects. The technique is demonstrated by inducing desired death mechanisms in epidermoid carcinoma and Burkitt lymphoma cells, and initiating efficient cell fusion between various cell types. Main advantages of the presented approach include low toxicity, high specificity, and high flexibility in the regulation of cell damage and cell fusion, which would allow it to play an important role in various future clinical and scientific applications.     

A Living Biotic–Abiotic Composite that can Switch Function Between Current Generation and Electrochemical Energy Storage

Power generation and charge storage devices are commonly uncoupled when it comes to the design of materials relevant for their fabrication. Here, it is demonstrated that the biotic–abiotic composite comprising the self-doped conjugated polyelectrolyte CPE-K and electrogenic bacteria Shewanella oneidensis MR-1 can reversibly switch its function between electrical current generation in chronoamperometry mode (≈150 mA m⁻²) and electrochemical energy storage as a pseudocapacitor with a specific capacitance of up to 80 F g⁻¹. Interconversion of desirable properties for the different functions is achieved by the simple addition and removal of Mg²⁺ in the bulk electrolyte. Potentiostatic, galvanostatic, and electrochemical impedance spectroscopy characterization, accompanied by imaging and cell viability tests, indicate that the modulation of properties is a result of reversible changes in CPE-K macrostructures and in the number of living bacteria within the composite. The results show the possibility to realize an “on-demand” switch between current generation and charge storage by one integrated “living” material.     

The CXCL2/IL8/CXCR2 Pathway Is Relevant for Brain Tumor Malignancy and Endothelial Cell Function

We aimed to evaluate the angiogenic capacity of CXCL2 and IL8 affecting human endothelial cells to clarify their potential role in glioblastoma (GBM) angiogenesis. Human GBM samples and controls were stained for proangiogenic factors. Survival curves and molecule correlations were obtained from the TCGA (The Cancer Genome Atlas) database. Moreover, proliferative, migratory and angiogenic activity of peripheral (HUVEC) and brain specific (HBMEC) primary human endothelial cells were investigated including blockage of CXCR2 signaling with SB225502. Gene expression analyses of angiogenic molecules from endothelial cells were performed. Overexpression of VEGF and CXCL2 was observed in GBM patients and associated with a survival disadvantage. Molecules of the VEGF pathway correlated but no relation for CXCR1/2 and CXCL2/IL8 was found. Interestingly, receptors of endothelial cells were not induced by addition of proangiogenic factors in vitro. Proliferation and migration of HUVEC were increased by VEGF, CXCL2 as well as IL8. Their sprouting was enhanced through VEGF and CXCL2, while IL8 showed no effect. In contrast, brain endothelial cells reacted to all proangiogenic molecules. Additionally, treatment with a CXCR2 antagonist led to reduced chemokinesis and sprouting of endothelial cells. We demonstrate the impact of CXCR2 signaling on endothelial cells supporting an impact of this pathway in angiogenesis of glioblastoma.     

A ceramic nanocomposite with enhanced hardness based on corundum modified with carbon

Results of examination of the effect of modifying the grain boundaries of nanostructured corundum with carbon nanoclusters on the nanocomposite hardness are reported. The nanocomposite hardness was found to be increased to 28 GPa. This value is substantially higher than the hardness of single-crystal corundum at any crystallographic plane (23 GPa). Carbon was present at grain boundaries in the obtained nanocomposite owing to the fact that this nanocomposite was sintered from clusters containing corundum nanograins coated with several C₆₀ layers. The structure of samples was investigated by transmission electron microscopy and Raman spectroscopy, and their hardness was measured by indenting and scratch testing.     

Mechanisms of current flow in metal-semiconductor ohmic contacts

Published data on the properties of metal-semiconductor ohmic contacts and mechanisms of current flow in these contacts (thermionic emission, field emission, thermal-field emission, and also current flow through metal shunts) are reviewed. Theoretical dependences of the resistance of an ohmic contact on temperature and the charge-carrier concentration in a semiconductor were compared with experimental data on ohmic contacts to II–VI semiconductors (ZnSe, ZnO), III–V semiconductors (GaN, AlN, InN, GaAs, GaP, InP), Group IV semiconductors (SiC, diamond), and alloys of these semiconductors. In ohmic contacts based on lightly doped semiconductors, the main mechanism of current flow is thermionic emission with the metal-semiconductor potential barrier height equal to 0.1–0.2 eV. In ohmic contacts based on heavily doped semiconductors, the current flow is effected owing to the field emission, while the metal-semiconductor potential barrier height is equal to 0.3–0.5 eV. In alloyed In contacts to GaP and GaN, a mechanism of current flow that is not characteristic of Schottky diodes (current flow through metal shunts formed by deposition of metal atoms onto dislocations or other imperfections in semiconductors) is observed.