Electrical conductivity measured in atomic carbon chains

The first electrical conductivity measurements of monoatomic carbon chains are reported in this study. The chains were obtained by unraveling carbon atoms from graphene ribbons while an electrical current flowed through the ribbon and, successively, through the chain. The formation of the chains was accompanied by a characteristic drop in the electrical conductivity. The conductivity of carbon chains was much lower than previously predicted for ideal chains. First-principles calculations using both density functional and many-body perturbation theory show that strain in the chains determines the conductivity in a decisive way. Indeed, carbon chains are always under varying non-zero strain that transforms its atomic structure from cumulene to polyyne configuration, thus inducing a tunable band gap. The modified electronic structure and the characteristics of the contact to the graphitic periphery explain the low conductivity of the locally constrained carbon chain.Comment: 21 pages, 9 figure

A 3D insight on the catalytic nanostructuration of few-layer graphene

The catalytic cutting of few-layer graphene is nowadays a hot topic in materials research due to its potential applications in the catalysis field and the graphene nanoribbons fabrication. We show here a 3D analysis of the nanostructuration of few-layer graphene by iron-based nanoparticles under hydrogen flow. The nanoparticles located at the edges or attached to the steps on the FLG sheets create trenches and tunnels with orientations, lengths and morphologies defined by the crystallography and the topography of the carbon substrate. The cross-sectional analysis of the 3D volumes highlights the role of the active nanoparticle identity on the trench size and shape, with emphasis on the topographical stability of the basal planes within the resulting trenches and channels, no matter the obstacle encountered. The actual study gives a deep insight on the impact of nanoparticles morphology and support topography on the 3D character of nanostructures built up by catalytic cutting

Kidins220/ARMS binds to the B cell antigen receptor and regulates B cell development and activation

B cell antigen receptor (BCR) signaling is critical for B cell development and activation. Using mass spectrometry, we identified a protein kinase D\u2013interacting substrate of 220 kD (Kidins220)/ankyrin repeat\u2013rich membrane-spanning protein (ARMS) as a novel interaction partner of resting and stimulated BCR. Upon BCR stimulation, the interaction increases in a Src kinase\u2013independent manner. By knocking down Kidins220 in a B cell line and generating a conditional B cell\u2013specific Kidins220 knockout (B-KO) mouse strain, we show that Kidins220 couples the BCR to PLC\u3b32, Ca2+, and extracellular signal-regulated kinase (Erk) signaling. Consequently, BCR-mediated B cell activation was reduced in vitro and in vivo upon Kidins220 deletion. Furthermore, B cell development was impaired at stages where pre-BCR or BCR signaling is required. Most strikingly, \u3bb light chain\u2013positive B cells were reduced sixfold in the B-KO mice, genetically placing Kidins220 in the PLC\u3b32 pathway. Thus, our data indicate that Kidins220 positively regulates pre-BCR and BCR functionin

Zmniejszanie osoczowego stężenia płytkopodobnego czynnika wzrostu przez duże dawki simwastatyny nie wpływa na stężenia markerów aktywacji immunologicznej

Wstęp: Korzystny efekt wczesnego stosowania statyn w ostrych zespołach wieńcowych (ACS) może wynikać z ich działania przeciwzapalnego i przeciwpłytkowego. Celem przedstawionego badania było porównanie wpływu standardowych i dużych dawek statyn w ACS na osoczowe wskaźniki markerów aktywacji płytek i układu immunologicznego. Materiał i metody: Czterdziestu czterech pacjentów z ACS leczonych przezskórną angioplastyka wieńcową przydzielono do 2 grup: S(+) - 22 chorych otrzymujących duże dawki simwastatyny (80 mg/d.) przez 1 miesiąc od wystąpienia ACS oraz S(–) - 22 pacjentów leczonych standardowymi dawkami statyn. Laboratoryjne oznaczenia obejmowały określenie stężeń w surowicy krwi: TNF-α, sTNFR 1 i 2, IL-2, IL-10 oraz PDGF wyjściowo, po 7. i 30. dniu od wystąpienia ostrego zespołu wieńcowego. Wyniki: Przebieg kliniczny ACS i wyjściowe stężenia ocenianych markerów były porównywalne w badanych grupach. Nie odnotowano różnic w kolejnych oznaczeniach stężeń TNF-α, sTNFR 1, sTNFR 2, IL-2 i IL-10. Stężenie PDGF korelowało negatywnie z terapią dużą dawką simwastatyny (r = –0,416; p = 0,014) i było istotnie mniejsze w 7. i 30. dniu w grupie S(+) (odpowiednio: 6111 ± 1834 pg/ml; p = 0,037 i 5735 ± 1089 pg/ml; p = 0,016) w porównaniu z grupą S(–) (odpowiednio: 7292 ± 1952 pg/ml; 7034 ± 2008 pg/ml). Wnioski: Stosowanie dużych dawek simwastatyny w ciągu 1 miesiąca od ACS wiąże się z istotnym obniżeniem osoczowego stężenia PDGF, natomiast nie wpływa na wartości stężeń innych markerów aktywacji immunologicznej

A novel mechanical cleavage method for synthesizing few-layer graphenes

A novel method to synthesize few layer graphene from bulk graphite by mechanical cleavage is presented here. The method involves the use of an ultrasharp single crystal diamond wedge to cleave a highly ordered pyrolytic graphite sample to generate the graphene layers. Cleaving is aided by the use of ultrasonic oscillations along the wedge. Characterization of the obtained layers shows that the process is able to synthesize graphene layers with an area of a few micrometers. Application of oscillation enhances the quality of the layers produced with the layers having a reduced crystallite size as determined from the Raman spectrum. Interesting edge structures are observed that needs further investigation

A 3D insight on the catalytic nanostructuration of few-layer graphene

The catalytic cutting of few-layer graphene is nowadays a hot topic in materials research due to its potential applications in the catalysis field and the graphene nanoribbons fabrication. We show here a 3D analysis of the nanostructuration of few-layer graphene by iron-based nanoparticles under hydrogen flow. The nanoparticles located at the edges or attached to the steps on the FLG sheets create trenches and tunnels with orientations, lengths and morphologies defined by the crystallography and the topography of the carbon substrate. The cross-sectional analysis of the 3D volumes highlights the role of the active nanoparticle identity on the trench size and shape, with emphasis on the topographical stability of the basal planes within the resulting trenches and channels, no matter the obstacle encountered. The actual study gives a deep insight on the impact of nanoparticles morphology and support topography on the 3D character of nanostructures built up by catalytic cutting

Label-free Detection of Influenza Viruses using a Reduced Graphene Oxide-based Electrochemical Immunosensor Integrated with a Microfluidic Platform

Reduced graphene oxide (RGO) has recently gained considerable attention for use in electrochemical biosensing applications due to its outstanding conducting properties and large surface area. This report presents a novel microfluidic chip integrated with an RGO-based electrochemical immunosensor for label-free detection of an influenza virus, H1N1. Three microelectrodes were fabricated on a glass substrate using the photolithographic technique, and the working electrode was functionalized using RGO and monoclonal antibodies specific to the virus. These chips were integrated with polydimethylsiloxane microchannels. Structural and morphological characterizations were performed using X-ray photoelectron spectroscopy and scanning electron microscopy. Electrochemical studies revealed good selectivity and an enhanced detection limit of 0.5 PFU mL(-1), where the chronoamperometric current increased linearly with H1N1 virus concentration within the range of 1 to 104 PFU mL(-1) (R-2 = 0.99). This microfluidic immunosensor can provide a promising platform for effective detection of biomolecules using minute samples.ope

A highly N-doped carbon phase "dressing" of macroscopic supports for catalytic applications

© The Royal Society of Chemistry 2015. The straightforward "dressing" of macroscopically shaped supports (i.e. β-SiC and α-Al2O3) with a mesoporous and highly nitrogen-doped carbon-phase starting from food-processing raw materials is described. The as-prepared composites serve as highly efficient and selective metal-free catalysts for promoting industrial key-processes at the heart of renewable energy technology and environmental protection