Chemical Production and Microelectronic Applications of Graphene and Nano-Graphene Derivatives

Graphene and graphenic derivatives have rapidly emerged as an extremely promising system for electronic, optical, thermal, and electromechanical applications. Several approaches have been developed to produce these materials (i.e. scotch tape, CVD, chemical and solvent exfoliation). In this work we report a chemical approach to produce graphene by reducing graphene oxide (GO) via thermal or electrical methods. A morphological and electrical characterization of these systems has been performed using different techniques such as SPM, SEM, TEM, Raman and XPS. Moreover, we studied the interaction between graphene derivates and organic molecules focusing on the following aspects: - improvement of optical contrast of graphene on different substrates for rapid monolayer identification1 - supramolecular interaction with organic molecules (i.e. thiophene, pyrene etc.)4 - covalent functionalization with optically active molecules2 - preparation and characterization of organic/graphene Field Effect Transistors3-5 Graphene chemistry can potentially allow seamless integration of graphene technology in organic electronics devices to improve device performance and develop new applications for graphene-based materials. [1] E. Treossi, M. Melucci, A. Liscio, M. Gazzano, P. Samorì, and V. Palermo, J. Am. Chem. Soc., 2009, 131, 15576. [2] M. Melucci, E. Treossi, L. Ortolani, G. Giambastiani, V. Morandi, P. Klar, C. Casiraghi, P. Samorì, and V. Palermo, J. Mater. Chem., 2010, 20, 9052. [3] J.M. Mativetsky, E. Treossi, E. Orgiu, M. Melucci, G.P. Veronese, P. Samorì, and V. Palermo, J. Am. Chem. Soc., 2010, 132, 14130. [4] A. Liscio, G.P. Veronese, E. Treossi, F. Suriano, F. Rossella, V. Bellani, R. Rizzoli, P. Samorì and V. Palermo, J. Mater. Chem., 2011, 21, 2924. [5] J.M. Mativetsky, A. Liscio, E. Treossi, E. Orgiu, A. Zanelli, P. Samorì , V. Palermo, J. Am. Chem. Soc., 2011, 133, 14320

Improvements in production and storage of HP-129 Xe

Seit seiner Entdeckung im Jahre 1978 wurden für hyperpolarisiertes (HP) 129Xe zahlreiche Anwendungen gefunden. Aufgrund seiner hohen Verstärkung von NMR-Signalen wird es dabei typischerweise für Tracer- und Oberflächenstudien verwendet. Im gasförmigen Zustand ist es ein interessantes, klinisches Kontrastmittel, welches für dynamische Lungen MRT genutzt oder auch in Blut oder lipophilen Flüssigkeiten gelöst werden kann. Weiterhin findet HP-Xe auch in der Grundlagenphysik in He-Xe Co-Magnetometern Verwendung, mit welchen z. B. das elektrische Dipolmoment von Xe bestimmt werden soll, oder es dient zur Überprüfung auf Lorentz-Invarianzen. Alle diese Anwendungen profitieren von einem hohen Polarisationsgrad (PXe), um hohe Signalstärken und lange Lagerzeiten zu erreichen. rnIn dieser Arbeit wurden zwei mobile Xe-Polarisatoren konstruiert: einer für Experimente in der Grundlagenphysik mit einer Produktionsrate von 400 mbar·l/h mit PXe ≈ 5%. Der zweite Xe-Polarisator wurde für medizinische Anwendungen entwickelt und soll 1 bar l/h mit PXe > 20% erzeugen. Der letztere wurde noch nicht getestet. Die Arbeitsbedingungen des Xe-Polarisators für Grundlagenphysik (Strömung des Gasgemischs, Temperatur, Druck und Konzentration von Xe) wurden variiert, um einen höchstmöglichen Polarisationsgrad zu erzielen. Die maximale Polarisation von 5,6 % wurde bei Verwendung eine Gasmischung von 1% Xe bei einem Durchfluss von 200 ml/min, einer Temperatur von 150°C und einem Gesamtdruck von 4 bar erreicht. rnWeiterhin muss HP-Xe auch effizient gelagert werden, um Polarisationsverluste zu minimieren. Das ist besonders für solche Anwendungen notwendig, welche an einem entfernten Standort durchgeführt werden sollen oder auch wenn lange Spinkohärenzeiten gefordert sind, z.B. bei He-Xe Co-Magnetometern. rnHierbei bestand bisher die größte Schwierigkeit darin, die Reproduzierbarkeit der gemessenen Lagerzeiten sicherzustellen. In dieser Arbeit konnte die Spin-Gitter-Relaxationszeit (T1) von HP-129Xe in unbeschichteten, Rb-freien, sphärischen Zellen aus Aluminiumsilikatglas (GE-180) signifikant verbessert werden. Die T1–Zeit wurde in einem selbstgebauten Niederfeld-NMR-System (2 mT) sowohl für reines HP-Xe als auch für HP-Xe in Mischungen mit N2, SF6 und CO2 bestimmt. Bei diesen Experimenten wurde die maximale Relaxationszeit für reines Xe (85% 129 Xe) bei (4,6 ± 0,1) h festgestellt. Dabei lagen die typischen Wand-Relaxationszeiten bei ca. 18 h für Glaszellen mit einem Durchmesser von 10 cm. Des Weiteren wurde herausgefunden, dass CO2 eine unerwartet hohe Effizienz bei der Verkürzung der Lebensdauer der Xe-Xe Moleküle zeigte und somit zu einer deutlichen Verlängerung der gesamten T1-Zeit genutzt werden kann. rnIm Verlauf vieler Experimente wurde durch wiederholte Messungen mit der gleichen Zelle, ein "Alterungsprozess“ bei der Wandrelaxation identifiziert und untersucht. Dieser Effekt könnte leicht rückgängig gemacht werden, indem die anfängliche Reinigungsprozedur wiederholt wurde. Auf diese Weise kann eine konstante Wandrelaxation sichergestellt werden, durch die sehr reproduzierbare T1-Messungen möglich werden. rnSchließlich wurde die maximale Relaxationszeit für HP-Xe mit natürlicher Häufigkeit in Mischungen mit SF6 bestimmt. Überraschenderweise war dieser Wert um ca. 75% niedriger als der Wert für Xenon, das zu 85% mit 129Xe angereichert war. Dieser Effekt wurde durch drei unabhängige Experimente bestätigt, da er nicht von der bestehenden Theorie der Xe-Relaxation ableitbar ist. rnDie Polarisation von HP-Xe, PXe, wird normalerweise durch den Vergleich der NMR-Signale des HP-Xe mit einer thermischen polarisierten Probe (z. B. 1H2O oder Xe) bestimmt. Dabei beinhaltet der Vergleich unterschiedlicher Messungen an verschiedenen Proben (unterschiedlicher Druck, Signalintensität und Messverfahren) viele experimentelle Unsicherheiten, welche sich oft nicht leicht bestimmen lassen. Eine einfache, genaue und kostengünstige Methode zur Bestimmung von PXe durch eine direkte Messung der makroskopischen Magnetisierung in einem statischen Magnetfeld vermeidet alle diese Unsicherheiten. Dieses Verfahren kann Polarisationen von > 2 % mit einer Genauigkeit von maximal 10% fast ohne Polarisationsverlust bestimmen. Zusätzlich kann diese Methode ohne weitere Änderungen auch für Bestimmungen des Polarisationsgrades anderer HP-Gase verwendet werden.rn

Mannan-binding lectin deficiency results in unusual antibody production and excessive experimental colitis in response to mannose-expressing mild gut pathogens

In Crohn's disease (CD) the deficiency of mannan-binding lectin (MBL) is associated with an increased prevalence of anti-Saccharomyces cerevisiae antibodies (ASCA) and with complicated phenotypes of the disease. However, the role of MBL in intestinal inflammation is currently unclear. A study was undertaken to analyse local MBL expression in human intestine and the consequences of MBL deficiency in experimental colitis and yeast infection.

Rapid Facilitation of Ultrasound Production and Lordosis in Female Hamsters by Horizontal Cuts Between the Septum and Preoptic Area

Horizontal cuts between the septum and preoptic area (anterior roof deafferentation, or ARD) dramatically affect sexual behavior, and in ways that could explain a variety of differences across behavioral categories (precopulatory, copulatory), species, and the sexes. Yet little is known about how these effects develop. Such information would be useful generally and could be pivotal in clarifying the mechanism for ultrasonic vocalization in female hamsters. Ultrasounds serve these animals as precopulatory signals that can attract males and help initiate mating. Their rates can be increased by either ARD or lesions of the ventromedial hypothalamus (VMN). If these effects are independent, they would require a mechanism that includes multiple structures and pathways within the forebrain and hypothalamus. However, it currently is not clear if they are independent: VMN lesions could affect vocalization by causing incidental damage to the same fibers targeted by ARD. Fortunately, past studies of VMN lesions have described a response with a very distinctive time course. This raises the possibility of assessing the independence of the two lesion effects by describing just the development of the response to ARD. To accomplish this, female hamsters were observed for levels of ultrasound production and lordosis before and after control surgery or ARD. As expected, both behaviors were facilitated by these cuts. Further, these effects began to appear by two days after surgery and were fully developed by six days. These results extend previous descriptions of the ARD effect by describing its development and time course. In turn, the rapid responses to ARD suggest that these cuts trigger disinhibitory changes in pathways that differ from those affected by VMN lesions. 2013

Comparing pneumococcal conjugate vaccine schedules based on 3 and 2 primary doses: systematic review and meta-analysis

Background Pneumococcal conjugate vaccines (PCV) were first licensed for use with 3 primary doses in infancy and a booster dose. The evidence for the effects of different schedules was examined in this systematic review and meta-analysis. Methods We searched 12 databases and trial registers up to March 2010. We selected randomised controlled trials (RCTs), cohort and case–control studies making direct comparisons between PCV schedules with (2p) or (3p) primary doses, with (+1) or without (+0) a booster dose. We extracted data on clinical, nasopharyngeal carriage and immunological outcomes and used meta-analysis to combine results where appropriate. Results Seropositivity levels (antibody concentration ≥0.35 μg/ml) following 3p and 2p PCV schedules were high for most serotypes (5 RCTs). Differences between schedules were generally small and tended to favour 3p schedules, particularly for serotypes 6B and 23F; between-study heterogeneity was high. Seropositivity levels following 3p+1 and 2p+1 schedules were similar but small differences favouring 3p+1 schedules were seen for serotypes 6B and 23F. We did not identify any RCTs reporting clinical outcomes for these comparisons. In 2 RCTs there was weak evidence of a reduction in carriage of S. pneumoniae serotypes included in the vaccine when 3p+0 schedules were compared to 2p+0 at 6 months of age. Conclusions Most data about the relative effects of different PCV schedules relate to immunological outcomes. Both 3p and 2p schedules result in high levels of seropositivity. The clinical relevance of differences in immunological outcomes between schedules is not known. There is an absence of clinical outcome data from RCTs with direct comparisons of any 2p with any 3p PCV schedule.

The production and composition of rat sebum is unaffected by 3 Gy gamma radiation

The aim of this work was to use metabolomics to evaluate sebum as a source of biomarkers for gamma-radiation exposure in the rat, and potentially in man. Proof of concept of radiation metabolomics was previously demonstrated in both mouse and rat urine, from the radiation dose- and time-dependent excretion of a set of urinary biomarkers.

Production and characterization of a custom-made 228Th source with reduced neutron source strength for the Borexino experiment

A custom-made 228Th source of several MBq activity was produced for the Borexino experiment for studying the external background of the detector. The aim was to reduce the unwanted neutron emission produced via (alpha,n) reactions in ceramics used typically for commercial 228Th sources. For this purpose a ThCl4 solution was converted chemically into ThO2 and embedded into a gold foil. The paper describes the production and the characterization of the custom-made source by means of gamma-activity, dose rate and neutron source strength measurements. From gamma-spectroscopic measurements it was deduced that the activity transfer from the initial solution to the final source was >91% (at 68% C.L.) and the final activity was (5.41+-0.30) MBq. The dose rate was measured by two dosimeters yielding 12.1 mSv/h and 14.3 mSv/h in 1 cm distance. The neutron source strength of the 5.41 MBq 228Th source was determined as (6.59+-0.85)/sec.

Wgamma production and limits on anomalous WWgamma couplings in ppbar collisions

We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W -> lnu+gamma production in egamma and mugamma final states. Using data corresponding to an integrated luminosity of 4.2 fb-1 collected with the D0 detector at the Fermilab Tevatron Collider, the cross section multiplied by the branching fraction for the process ppbar -> Wgamma+X -> lnugamma+X, measured to be 15.8 +/- 0.8 (stat.) +/- 1.2 (syst.) pb, and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WWgamma couplings for data from hadron colliders: -0.4 < Delta kappa_gamma < 0.4 and -0.08 < lambda_gamma < 0.07 at the 95% C.L.

Changes in retention force with electroplated copings on conical crowns: a comparison of gold and zirconia primary crowns

The aim of this study was to examine the wear behavior of conical crowns with electroplated gold copings that are used to connect implants and teeth to a removable denture. Gold alloy and zirconium dioxide ceramic crowns were compared.

What makes the difference between the natural course of a remaining type B dissection after type A repair and a primary type B aortic dissection?

To analyse the outcome and need for intervention [surgery or thoracic endovascular aortic repair (TEVAR)] in patients after surgery for remaining type B dissection after type A repair and primary type B aortic dissection.

Cloning, production and characterization of antigen 5 like proteins from Simulium vittatum and Culicoides nubeculosus, the first cross-reactive allergen associated with equine insect bite hypersensitivity

Insect bite hypersensitivity (IBH) is an IgE-mediated seasonal dermatitis of the horses associated with bites of Simulium (black fly) and Culicoides (midge) species. Although cross-reactivity between Simulium and Culicoides salivary gland extracts has been demonstrated, the molecular nature of the allergens responsible for the observed cross-reactivity remains to be elucidated. In this report we demonstrate for the first time in veterinary medicine that a homologous allergen, present in the salivary glands of both insects, shows extended IgE cross-reactivity in vitro and in vivo. The cDNA sequences coding for both antigen 5 like allergens termed Sim v 1 and Cul n 1 were amplified by PCR, subcloned in high level expression vectors, and produced as [His](6)-tagged proteins in Escherichia coli. The highly pure recombinant proteins were used to investigate the prevalence of sensitization in IBH-affected horses by ELISA and their cross-reactive nature by Western blot analyses, inhibition ELISA and intradermal skin tests (IDT). The prevalence of sensitization to Sim v 1 and Cul n 1 among 48 IBH-affected horses was 37% and 35%, respectively. In contrast, serum IgE levels to both allergens in 24 unaffected horses did not show any value above background. Both proteins strongly bound serum IgE from IBH-affected horses in Western blot analyses, demonstrating the allergenic nature of the recombinant proteins. Extended inhibition ELISA experiments clearly showed that Sim v 1 in fluid phase is able to strongly inhibit binding of serum IgE to solid phase coated Cul n 1 in a concentration dependent manner and vice versa. This crucial experiment shows that the allergens share common IgE-binding epitopes. IDT with Sim v 1 and Cul n 1 showed clear immediate and late phase reactions to the allergen challenges IBH-affected horses, whereas unaffected control horses do not develop relevant immediate hypersensitivity reactions. In some horses, however, mild late phase reactions were observed 4h post-challenge, a phenomenon reported to occur also in challenge experiments with Simulium and Culicoides crude extracts probably related to lipopolysaccaride contaminations which are also present in E. coli-expressed recombinant proteins. In conclusion our data demonstrate that IgE-mediated cross-reactivity to homologous allergens, a well-known clinically relevant phenomenon in human allergy, also occurs in veterinary allergy.