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Insights into the Early Growth of Homogeneous Single-Layer Graphene over Ni–Mo Binary Substrates
Rü,mmeli, Mark H.,Zeng, Mengqi,Melkhanova, Svetlana,Gorantla, Sandeep,Bachmatiuk, Alicja,Fu, Lei,Yan, Chenglin,Oswald, Steffen,Mendes, Rafael G.,Makarov, Denys,Schmidt, Oliver,Eckert, Jü,r American Chemical Society 2013 Chemistry of materials Vol.25 No.19
<P>The employment of Ni–Mo films has recently been shown to yield strictly homogeneous single-layer graphene. In this study, we systematically investigate the different stages of nucleation and growth of graphene over Ni–Mo layers. The studies reveal that the Ni film breaks up and diffuses into the underlying Mo foil, forming a Ni–Mo intermetallic. Nucleation only occurs from Ni sites, and thus, the nucleation density can be controlled by the Ni film thickness. Both nucleation and growth of the graphene are shown to be susceptible to very efficient self-termination processes to the formation of molybdenum carbide, and this guarantees the formation of large area graphene that consists <I>entirely</I> of monolayer graphene.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2013/cmatex.2013.25.issue-19/cm4020783/production/images/medium/cm-2013-020783_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm4020783'>ACS Electronic Supporting Info</A></P>
Po-Yi Lue,Mark H. Oliver,Michel Neeff,Peter R. Thorne,Haruna Suzuki-Kerr 한국실험동물학회 2023 Laboratory Animal Research Vol.39 No.4
Sensorineural hearing loss (SNHL), caused by pathology in the cochlea, is the most common type of hearing loss in humans. It is generally irreversible with very few effective pharmacological treatments available to prevent the degenerative changes or minimise the impact. Part of this has been attributed to difficulty of translating “proof-of-concept” for novel treatments established in small animal models to human therapies. There is an increasing interest in the use of sheep as a large animal model. In this article, we review the small and large animal models used in pre-clinical hearing research such as mice, rats, chinchilla, guinea pig, rabbit, cat, monkey, dog, pig, and sheep to humans, and compare the physiology, inner ear anatomy, and some of their use as model systems for SNHL, including cochlear implantation surgeries. Sheep have similar cochlear anatomy, auditory threshold, neonatal auditory system development, adult and infant body size, and number of birth as humans. Based on these comparisons, we suggest that sheep are well-suited as a potential translational animal model that bridges the gap between rodent model research to the clinical use in humans. This is especially in areas looking at changes across the life-course or in specific areas of experimental investigation such as cochlear implantation and other surgical procedures, biomedical device development and age-related sensorineural hearing loss research. Combined use of small animals for research that require higher throughput and genetic modification and large animals for medical translation could greatly accelerate the overall translation of basic research in the field of auditory neuroscience from bench to clinic.
Vertical Graphene Growth from Amorphous Carbon Films Using Oxidizing Gases
Bachmatiuk, Alicja,Boeckl, John,Smith, Howard,Ibrahim, Imad,Gemming, Thomas,Oswald, Steffen,Kazmierczak, Wojciech,Makarov, Denys,Schmidt, Oliver G.,Eckert, Juergen,Fu, Lei,Rummeli, Mark H. American Chemical Society 2015 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.119 No.31
<P>Amorphous carbon thin films are technologically important materials that range in use from the semiconductor industry to corrosion-resistant films. Their conversion to crystalline graphene layers has long been pursued; however, typically this requires excessively high temperatures. Thus, crystallization routes which require reduced temperatures are important. Moreover, the ability to crystallize amorphous carbon at reduced temperatures without a catalyst could pave the way for practical graphene synthesis for device fabrication without the need for transfer or post-transfer gate deposition. To this end we demonstrate a practical and facile method to crystallize deposited amorphous carbon films to high quality graphene layers at reduced annealing temperatures by introducing oxidizing gases during the process. The reactive gases react with regions of higher strain (energy) in the system and accelerate the graphitization process by minimizing criss-cross-linkages and accelerating C–C bond rearrangement at defects. In other words, the movement of crystallite boundaries is accelerated along the carbon hexagon planes by removing obstacles for crystallite coalescence.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2015/jpccck.2015.119.issue-31/acs.jpcc.5b05167/production/images/medium/jp-2015-05167v_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp5b05167'>ACS Electronic Supporting Info</A></P>
A size dependent evaluation of the cytotoxicity and uptake of nanographene oxide
Mendes, Rafael Gregorio,Koch, Britta,Bachmatiuk, Alicja,Ma, Xing,Sanchez, Samuel,Damm, Christine,Schmidt, Oliver G.,Gemming, Thomas,Eckert, Jü,rgen,Rü,mmeli, Mark H. The Royal Society of Chemistry 2015 Journal of Materials Chemistry B Vol.3 No.12
<P>Graphene oxide (GO) has attracted great interest due to its extraordinary potential for biomedical application. Although it is clear that the naturally occurring morphology of biological structures is crucial to their precise interactions and correct functioning, the geometrical aspects of nanoparticles are often ignored in the design of nanoparticles for biological applications. A few <I>in vitro</I> and <I>in vivo</I> studies have evaluated the cytotoxicity and biodistribution of GO, however very little is known about the influence of flake size and cytotoxicity. Herein, we aim at presenting an initial cytotoxicity evaluation of different nano-sized GO flakes for two different cell lines (HeLa (Kyoto) and macrophage (J7742)) when they are exposed to samples containing different sized nanographene oxide (NGO) flakes (mean diameter of 89 and 277 nm). The obtained data suggests that the larger NGO flakes reduce cell viability as compared to smaller flakes. In addition, the viability reduction correlates with the time and the concentration of the NGO nanoparticles to which the cells are exposed. Uptake studies were also conducted and the data suggests that both cell lines internalize the GO nanoparticles during the incubation periods studied.</P>
Ibrahim, Imad,Kalbacova, Jana,Engemaier, Vivienne,Pang, Jinbo,Rodriguez, Raul D.,Grimm, Daniel,Gemming, Thomas,Zahn, Dietrich R. T.,Schmidt, Oliver G.,Eckert, Jü,rgen,Rü,mmeli, Mark H. American Chemical Society 2015 Chemistry of materials Vol.27 No.17
<P>The search for ways to synthesize single wall carbon nanotubes (SWCNT) of a given electronic type in a controlled manner persists despite great challenges because the potential rewards are huge, in particular as a material beyond silicon. In this work we take a systematic look at three primary aspects of semiconducting enriched SWCNT grown by chemical vapor deposition. The role of catalyst choice, substrate, and feedstock mixture are investigated. In terms of semiconducting yield enhancement, little influence is found from either the binary catalyst or substrate choice. However, a very clear enrichment is found as one adds nominal amounts of methanol to an ethanol feedstock. Yields of up to 97% semiconducting SWCNT are obtained. These changes are attributed to two known etchant processes. In the first, metal SWCNT are preferentially etched. In the second, we reveal etchants also preferentially etch small diameter tubes because they are more reactive. The etchants are confirmed to have a dual role, to preferentially etch metallic tubes and narrow diameter tubes (both metallic and semiconducting) which results in a narrowing of the SWCNT diameter distribution.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/cmatex/2015/cmatex.2015.27.issue-17/acs.chemmater.5b02037/production/images/medium/cm-2015-02037h_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/cm5b02037'>ACS Electronic Supporting Info</A></P>