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Eckert, Jana K.,Kim, Young J.,Kim, Jung I.,Gurtler, K.,Oh, D.Y.,Sur, S.,Lundvall, L.,Hamann, L.,van der Ploeg, A.,Pickkers, P.,Giamarellos-Bourboulis, E.,Kubarenko, Andriy V.,Weber, Alexander N.,Kabes Cell Press 2013 Immunity Vol.39 No.4
Lipopolysaccharide (LPS) binding protein (LBP) is an acute-phase protein that initiates an immune response after recognition of bacterial LPS. Here, we report the crystal structure of murine LBP at 2.9 A resolution. Several structural differences were observed between LBP and the related bactericidal/permeability-increasing protein (BPI), and the LBP C-terminal domain contained a negatively charged groove and a hydrophobic ''phenylalanine core.'' A frequent human LBP SNP (allelic frequency 0.08) affected this region, potentially generating a proteinase cleavage site. The mutant protein had a reduced binding capacity for LPS and lipopeptides. SNP carriers displayed a reduced cytokine response after in vivo LPS exposure and lower cytokine concentrations in pneumonia. In a retrospective trial, the LBP SNP was associated with increased mortality rates during sepsis and pneumonia. Thus, the structural integrity of LBP may be crucial for fighting infections efficiently, and future patient stratification might help to develop better therapeutic strategies.
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>
Glassy Dynamics in Giant Magnetoresistive Melt - spun Co - Cu
B. Idzikowski,U. K. Röβler,A. Handstein,D. Eckert,M. Wolf,K. Nenkov,K.-H. Müller 한국자기학회 1999 Journal of Magnetics Vol.4 No.3
We report results on metastable CuCo ribbons at low Co contents (2 and 10 at%), which were prepared by conventional melt-spinning technique and subsequent annealing. The properties of these materials cannot consistently be described by those of an assembly of superparamagnetic single-domain particles. Magnetic measurements related to magnetic dynamics reveal spin-glass-like properties. Especially, we find very slow nonequilibrium relaxation processes in Co_(10)Cu_(90), which depend on prehistory, when probing the relaxation of the resistivity. The results are clear evidence for frustrated interaction effects due to magnetic couplings between Co clusters or precipitates in these alloys.
Schwarz, B.,Vainio, U.,Mattern, N.,Sohn, S.W.,Oswald, S.,Kim, D.H.,Eckert, J. North-Holland 2011 Journal of non-crystalline solids Vol.357 No.6
CuZr as well as CoZr are well known metallic glass-formers in a wide compositional range. Since the binary Cu-Co system exhibits a metastable liquid-liquid miscibility gap, i.e. Cu and Co tend to separate from each other, the ternary Cu-Co-Zr system is a promising candidate to form phase separated glass-glass composites. In this work (Cu<SUB>60</SUB>Co<SUB>40</SUB>)<SUB>1-x</SUB>Zr<SUB>x</SUB> metallic glasses with relatively low Zr contents of x=37 and x=32 were prepared by melt spinning and investigated by in-situ small-angle and wide-angle X-ray scattering (SAXS/WAXS) and differential scanning calorimetry (DSC). Certain heat treated samples were additionally investigated by high-resolution transmission electron microscopy (HRTEM). Even for x=32 there are no indications for any kind of phase separation in the as-quenched state within experimental resolution, i.e. the critical temperature T<SUB>c</SUB> for a liquid-liquid phase separation has already decreased from 1556K for binary Cu<SUB>60</SUB>Co<SUB>40</SUB> to a temperature below the glass transition temperature T<SUB>g</SUB>=762(5)K found for (Cu<SUB>60</SUB>Co<SUB>40</SUB>)<SUB>68</SUB>Zr<SUB>32</SUB>. Combined in-situ SAXS/WAXS and HRTEM investigations reveal that thermal annealing also does not induce an amorphous-amorphous phase separation. Instead the formation of nano crystallites of a so far unknown Cu-rich/Zr-poor phase with relatively low activation energy for crystallization E<SUB>a</SUB>=116(7)kJ/mol at temperatures far below the crystallization temperature deduced from DSC measurements is observed.
Kim, K.B.,Das, J.,Lö,ser, W.,Lee, M.H.,Kim, D.H.,Roy, S.K.,Eckert, J. Elsevier 2007 Materials science & engineering. properties, micro Vol.449 No.-
<P><B>Abstract</B></P><P>Zr<SUB>73.5</SUB>Nb<SUB>9</SUB>Cu<SUB>7</SUB>Ni<SUB>1</SUB>Al<SUB>9.5</SUB> (numbers indicate at.%) nanostructure-dendrite composites were fabricated using three different casting techniques: suction casting, centrifugal casting and arc-melting. The microstructure of the suction casting sample consists of micrometer-scale dendrites in a nanostructured matrix. However, some areas in the matrix contain nano-scale crystals together with an amorphous phase revealing an inhomogeneity of the specimen. On the contrary, the microstructures of the centrifugally-cast and the arc-melted samples are overall homogeneous, consisting of micrometer-scale dendrites that are homogeneously distributed in a nanostructured matrix. The dendrites correspond to a body centered cubic (bcc) β-Zr phase, whereas the nanostructured matrix consists of body centered tetragonal (bct) Zr<SUB>2</SUB>Cu-type and hexagonal close-packed (hcp) MgZn<SUB>2</SUB>-type phases. The comparison of the microstructures of these two alloys reveals that the formation of nano-scale twins and a disordered ω-phase in the β-Zr dendrites only happens in the centrifugally-cast sample. The differences in the phases and the microstructures between the differently prepared samples significantly influence the corresponding mechanical properties of the specimens.</P>
Criteria for tensile plasticity in Cu–Zr–Al bulk metallic glasses
Pauly, S.,Liu, G.,Gorantla, S.,Wang, G.,Kü,hn, U.,Kim, D.H.,Eckert, J. Elsevier 2010 Acta materialia Vol.58 No.14
<P><B>Abstract</B></P><P>(Cu<SUB>0.5</SUB>Zr<SUB>0.5</SUB>)<SUB>100−</SUB><I><SUB>x</SUB></I>Al<I><SUB>x</SUB></I> (<I>x</I>=5, 6, 8) bulk metallic glasses (BMGs) were deformed in tension. Besides ductility up to 0.5%, the material shows work-hardening behaviour. Both effects are attributed to the deformation-induced precipitation of B2 CuZr nanocrystals and the formation of twins in the nanocrystals larger than 20nm. The precipitation of the nanocrystals alters the stress field in the matrix and is expected to retard shear band propagation, which in turn allows stresses in the nanocrystals to rise. This stress build-up is more severe in the larger grains and might be responsible for the subsequent twinning. Both deformation-induced nanocrystallization and twinning consume energy and avoid crack formation and with it premature failure.</P>