Magnetic and Cytotoxicity Properties of La1−xSrxMnO3(0 ≤ x ≤ 0.5) Nanoparticles Prepared by a Simple Thermal Hydro-Decomposition

This study reports the magnetic and cytotoxicity properties of magnetic nanoparticles of La1−xSrxMnO3(LSMO) withx = 0, 0.1, 0.2, 0.3, 0.4, and 0.5 by a simple thermal decomposition method by using acetate salts of La, Sr, and Mn as starting materials in aqueous solution. To obtain the LSMO nanoparticles, thermal decomposition of the precursor was carried out at the temperatures of 600, 700, 800, and 900 °C for 6 h. The synthesized LSMO nanoparticles were characterized by XRD, FT-IR, TEM, and SEM. Structural characterization shows that the prepared particles consist of two phases of LaMnO3(LMO) and LSMO with crystallite sizes ranging from 20 nm to 87 nm. All the prepared samples have a perovskite structure with transformation from cubic to rhombohedral at thermal decomposition temperature higher than 900 °C in LSMO samples ofx ≤ 0.3. Basic magnetic characteristics such as saturated magnetization (MS) and coercive field (HC) were evaluated by vibrating sample magnetometry at room temperature (20 °C). The samples show paramagnetic behavior for all the samples withx = 0 or LMO, and a superparamagnetic behavior for the other samples havingMSvalues of ~20–47 emu/g and theHCvalues of ~10–40 Oe, depending on the crystallite size and thermal decomposition temperature. Cytotoxicity of the synthesized LSMO nanoparticles was also evaluated with NIH 3T3 cells and the result shows that the synthesized nanoparticles were not toxic to the cells as determined from cell viability in response to the liquid extract of LSMO nanoparticles

Staphylococcus aureus Keratinocyte Invasion Is Dependent upon Multiple High-Affinity Fibronectin-Binding Repeats within FnBPA

Staphylococcus aureus is a commensal organism and a frequent cause of skin and soft tissue infections, which can progress to serious invasive disease. This bacterium uses its fibronectin binding proteins (FnBPs) to invade host cells and it has been hypothesised that this provides a protected niche from host antimicrobial defences, allows access to deeper tissues and provides a reservoir for persistent or recurring infections. FnBPs contain multiple tandem fibronectin-binding repeats (FnBRs) which bind fibronectin with varying affinity but it is unclear what selects for this configuration. Since both colonisation and skin infection are dependent upon the interaction of S. aureus with keratinocytes we hypothesised that this might select for FnBP function and thus composition of the FnBR region. Initial experiments revealed that S. aureus attachment to keratinocytes is rapid but does not require FnBRs. By contrast, invasion of keratinocytes was dependent upon the FnBR region and occurred via similar cellular processes to those described for endothelial cells. Despite this, keratinocyte invasion was relatively inefficient and appeared to include a lag phase, most likely due to very weak expression of α5β1 integrins. Molecular dissection of the role of the FnBR region revealed that efficient invasion of keratinocytes was dependent on the presence of at least three high-affinity (but not low-affinity) FnBRs. Over-expression of a single high-affinity or three low-affinity repeats promoted invasion but not to the same levels as S. aureus expressing an FnBPA variant containing three high-affinity repeats. In summary, invasion of keratinocytes by S. aureus requires multiple high-affinity FnBRs within FnBPA, and given the importance of the interaction between these cell types and S. aureus for both colonisation and infection, may have provided the selective pressure for the multiple binding repeats within FnBPA

The search campaign to identify and Image the Philae Lander on the surface of comet 67P/Churyumov-Gerasimenko

On the 12th of November 2014, the Rosetta Philae Lander descended to make the first soft touchdown on the surface of a comet – comet 67P/Churyumov- Gerasimenko. That soft touchdown did occur but due to the failure in the firing of its two harpoons, Philae bounced and travelled across the comet making contact with the surface twice more before finally landing in a shaded rocky location somewhere on the southern hemisphere of the comet. The search campaign, led by ESA, involved multiple teams across Europe with a wide range of techniques used in support of it. This search campaign would continue through 2015 where a prime candidate on the surface was identified and on into 2016 to end on the 2nd of September 2016 when a definitive and conclusive image was taken of the lander on the surface of the comet, confirming the prime candidate to indeed be Philae

Long-term follow-up of patients with congenital myasthenic syndrome caused by COLQ mutations.

Congenital myasthenic syndromes (CMS) are clinically and genetically heterogeneous inherited disorders characterized by impaired neuromuscular transmission. Mutations in the acetylcholinesterase (AChE) collagen-like tail subunit gene (COlQ) cause recessive forms of synaptic CMS with end plate AChE deficiency. We present data on 15 COLQ -mutant CMS carrying 16 different mutations (9 novel ones identified) followed-up for an average period of 10 ears. The mean age at the first examination was 19 ears old (range from 3 to 48). We report relapses during short or long-term periods characterized by worsening of muscle weakness sometimes associated with respiratory crises. All the relapses ended spontaneously or with 3-4 DAP or ephedrine with no residual impairment. The triggering factors identified were esterase inhibitors, effort, puberty or pregnancy highlighting the importance of hormonal factors. There was no genotype-phenotype correlation. At the end of the follow-up, 80% of patients were ambulant and 87% of patients had no respiratory trouble in spite of severe relapses

Rosetta Lander - Philae: Status after First Landon on a Comet

Rosetta is a Cornerstone Mission of the ESA Horizon 2000 programme [1,2]. In August 2014 it did rendezvous with comet 67P/Churyumov-Gerasimenko (CG) after a 10 year cruise. Both its nu-cleus and coma have been studied allowing the selec-tion of a landing site for Philae [3], the lander which successfully landed on the comet on November 12, 2014. It did, however, bounced off again and only came to rest after a leap of about 2 hours, approximate-ly one kilometer from the originally targeted site. Phi-lae was operational for almost 64 hours after separation and provided unique information from the surface of the comet. All ten instruments aboard could be operat-ed at least once. Descent and Landing: After injection of the Ro-setta spacecraft into the delivery orbit, Philae was ejected with a separation velocity of 18.76 cm/s on November 12th, 2014 at 8:35 UTC. This maneuver was performed perfectly, leading to a touch-down, about 7 hours later, at 15:34:04, only 51 seconds (!) before the precalculated landing time. The touch-down signal was received, the lander switched into the “on-comet mode” and started its first scientific sequence. However, the anchoring harpoons have not been fired and a cold gas system, intended to provide hold-down thrust could not be activated. Consequently, Philae bounced off the surface and was ballistically drifting above the comet surface. After 1:50 hours the Lander came to its final rest, after two more surface contacts. The Lander is now at a poorly illuminated location, the solar generator apparently provides power for only 1:20 hours per comet rotation. Fortunately communica-tions link with the Orbiter was possible very similar to the predicted time-slots. [4,5] Lander Search and Attempts for Re-activation: For the search of the lander and in order to re-construct the trajectory and bouncing, OSIRIS images (some of them showing the lander, shadow or footprints.), CONSERT ranging data, landing gear and solar gener-ator HK data as well as data from ROMAP, MUPUS, ROLIS and SESAME have been used. Consequently, the position and attitude of the Lander is fairly well determined, however it could not be identified on any of the OSIRIS NAC images, yet. Although Philae could not stay active after the bat-teries were depleted in November, there is a good chance for re-establishing contact, when comet and Lander are closer to the sun. A first attempt in March 2015 was not successful but by the time of the confer-ence (in June the heliocentric distance of 67P is only 1.45 AU, less than half as at the time of landing) we hope to be able to report on new data from Philae. Achnowledgements: Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by DLR, MPS, CNES and ASI with additional contri-butions from Hungary, UK, Finland, Ireland and Aus-tria. References: [1] Glaßmeier, K.-H., Böhnhardt, H., Koschny, D., Kührt, E. and Richter I., (2007) Space Science Rev. 128, pp. 1-21. [2] Biele, J. and Ulamec, S. (2008) Space Science Rev. 138, 275-289. [3] Ulamec, S. et al. (2015) Acta Astron., Vol. 107, pp. 79-86. [4] Ulamec, S. et al., Philae – First Landing on a Comet, 46th Lunar and Planetary Science Conference, abstract# 1121, Houston, 2015, [5] Biele, J. et al. The landing(s) of Philae and Inferences on Comet Surface Mechanical Properties, submitted to Science, 201

Cobalt--zinc molybdates as new blue pigments involving Co²⁺ in distorted trigonal bipyramids and octahedra

Zn1-xCoxMoO4 (x Pt space group. X-ray diffraction and Rietveld analyses reveal the occurrence of three highly distorted sites with equal occupancies corresponding to one trigonal bipyramidal CoO5 group and two octahedral CoO6 groups occupied by either Zn2+ or Co2+. Mo6+ ions are located in distorted tetrahedral sites. Electron paramagnetic resonance analysis allows characterization of the two kinds of environments with orthorhombic distortion related to two signals with different g values. The UV-vis spectra exhibit intense Co2+ d-d transitions associated with CoO5 and CoO6 chromophores between 1.9 and 2.6 eV in the visible domain and O-Mo charge transfer at the frontier between the UV and visible ranges. A blue-transmitted window can then be displayed. The formation of covalent MoO4 entities and polarizable Zn2+ cations creating highly distorted noncentrosymmetric sites partially occupied by Co2+ allows stabilization of the first blue pigment without Co2+ in the tetrahedral environment. Moreover, only 5-10% cobalt is necessary to get a strong blue hue because of the highly distorted sites leading to very important oscillator strengths