Dissociative multi-photon ionization of isolated uracil and uracil-adenine complexes

Recent multi-photon ionization (MPI) experiments on uracil revealed a fragment ion at m/z 84 that was proposed as a potential marker for ring opening in the electronically excited neutral molecule. The present MPI measurements on deuterated uracil identify the fragment as C3H4N2O+ (uracil+ less CO), a plausible dissociative ionization product from the theoretically predicted open-ring isomer. Equivalent measurements on thymine do not reveal an analogous CO loss channel, suggesting greater stability of the excited DNA base. MPI and electron impact ionization experiments have been carried out on uracil-adenine clusters in order to better understand the radiation response of uracil within RNA. Evidence for C3H4N2O+ production from multi-photon-ionized uracil-adenine clusters is tentatively attributed to a significant population of π-stacked configurations in the neutral beam

End-Fire Silicon Optical Phased Array with Half-Wavelength Spacing

We demonstrate a one-dimensional optical phased array on an integrated silicon platform for operation at 1.55 microns. Light is emitted end-fire from the chip edge where the waveguides are terminated. The innovative design and high confinement afforded by the silicon waveguides enables lambda/2 spacing (775-nm pitch) at the output. Steering is achieved by inducing a phase shift between the waveguides via integrated thermo-optic heaters. The device forms a beam with a FWHM angular width of 17 degrees, and we demonstrate beam steering over a 64 degrees range

Nanocomposites based on poly(glycerol sebacate) with silica nanoparticles with potential application in dental tissue engineering

"This is an Accepted Manuscript of an article published by Taylor & Francis inInternational Journal of Polymeric Materials and Polymeric Biomaterials on AUG 08 2020, available online: https://www.tandfonline.com/doi/full/10.1080/00914037.2019.1616197"[EN] Nanocomposites based on poly(glycerol sebacate) with silica nanoparticles were synthesized to explore their potential use in the biomedical field. The nanoparticles were two distinct polyhedral oligomeric silsesquioxanes (POSS), both used at 5% wt/wt concentration, specifically methacrylisobutyl POSS and methacryl POSS. These materials were investigated for their possible application as coatings as well as with regenerative purposes in dental engineering, and their viability for this application was assessed. Thus, pure PGS and nanohybrids thereof were obtained as scaffolds (that is, porous structures, designed with regenerative purposes) and as films (intended for coatings and to be used as controls).The authors acknowledge Dr. Kirsten Techmer from Geoscience Center of the Georg-August-University Gottingen for performing the EDX-SEM analysis, the assistance and advice of the Julich Center for Neutron Science (JCNS) and Institute for Complex Systems (ICS), Forschungszentrum Julich GmbH (Germany), and the Electron Microscopy Service of the Universitat Politecnica de Valencia (Spain). This work was partially funded by the Spanish Ministerio de Economía y Competitividad through DPI2015-65401-C3-2-R project and by the German Research Foundation [DFG/MWK INST 1525/39-1 FUGG]. A.V.-Ll. acknowledges the support of the Generalitat Valenciana, Conselleria de Educación, Investigación, Cultura y Deporte through project AEST/2018/014.Tallá Ferrer, C.; Vilariño, G.; Rizk, M.; Sydow, H.; Vallés Lluch, A. (2020). Nanocomposites based on poly(glycerol sebacate) with silica nanoparticles with potential application in dental tissue engineering. International Journal of Polymeric Materials. 69(12):761-772. https://doi.org/10.1080/00914037.2019.1616197S7617726912Wang, Y., Ameer, G. A., Sheppard, B. J., & Langer, R. (2002). A tough biodegradable elastomer. Nature Biotechnology, 20(6), 602-606. doi:10.1038/nbt0602-602Loh, X. J., Abdul Karim, A., & Owh, C. (2015). Poly(glycerol sebacate) biomaterial: synthesis and biomedical applications. Journal of Materials Chemistry B, 3(39), 7641-7652. doi:10.1039/c5tb01048aRai, R., Tallawi, M., Grigore, A., & Boccaccini, A. R. (2012). Synthesis, properties and biomedical applications of poly(glycerol sebacate) (PGS): A review. Progress in Polymer Science, 37(8), 1051-1078. doi:10.1016/j.progpolymsci.2012.02.001Serrano, M. C., Chung, E. J., & Ameer, G. A. (2010). Advances and Applications of Biodegradable Elastomers in Regenerative Medicine. Advanced Functional Materials, 20(2), 192-208. doi:10.1002/adfm.200901040Zhang, X., Jia, C., Qiao, X., Liu, T., & Sun, K. (2016). Porous poly(glycerol sebacate) (PGS) elastomer scaffolds for skin tissue engineering. Polymer Testing, 54, 118-125. doi:10.1016/j.polymertesting.2016.07.006MacDonald, R. A., Laurenzi, B. F., Viswanathan, G., Ajayan, P. M., & Stegemann, J. P. (2005). Collagen-carbon nanotube composite materials as scaffolds in tissue engineering. Journal of Biomedical Materials Research Part A, 74A(3), 489-496. doi:10.1002/jbm.a.30386Saito, N., Usui, Y., Aoki, K., Narita, N., Shimizu, M., Hara, K., … Endo, M. (2009). Carbon nanotubes: biomaterial applications. Chemical Society Reviews, 38(7), 1897. doi:10.1039/b804822nChawla, R., Tan, A., Ahmed, M., Crowley, C., Moiemen, N. S., Cui, Z., … Seifalian, A. M. (2014). A polyhedral oligomeric silsesquioxane–based bilayered dermal scaffold seeded with adipose tissue–derived stem cells: in vitro assessment of biomechanical properties. Journal of Surgical Research, 188(2), 361-372. doi:10.1016/j.jss.2014.01.006Campbell, K., Craig, D. Q. M., & McNally, T. (2008). Poly(ethylene glycol) layered silicate nanocomposites for retarded drug release prepared by hot-melt extrusion. International Journal of Pharmaceutics, 363(1-2), 126-131. doi:10.1016/j.ijpharm.2008.06.027Scott, D. W. (1946). Thermal Rearrangement of Branched-Chain Methylpolysiloxanes1. Journal of the American Chemical Society, 68(3), 356-358. doi:10.1021/ja01207a003Conejero-García, Á., Gimeno, H. R., Sáez, Y. M., Vilariño-Feltrer, G., Ortuño-Lizarán, I., & Vallés-Lluch, A. (2017). Correlating synthesis parameters with physicochemical properties of poly(glycerol sebacate). European Polymer Journal, 87, 406-419. doi:10.1016/j.eurpolymj.2017.01.001Gao, J., Crapo, P. M., & Wang, Y. (2006). Macroporous Elastomeric Scaffolds with Extensive Micropores for Soft Tissue Engineering. Tissue Engineering, 12(4), 917-925. doi:10.1089/ten.2006.12.917Klimek, J., Hellwig, E., & Ahrens, G. (1982). Fluoride Taken Up by Plaque, by the Underlying Enamel and by Clean Enamel from Three Fluoride Compounds in vitro. Caries Research, 16(2), 156-161. doi:10.1159/000260592Zhao, X., Wu, Y., Du, Y., Chen, X., Lei, B., Xue, Y., & Ma, P. X. (2015). A highly bioactive and biodegradable poly(glycerol sebacate)–silica glass hybrid elastomer with tailored mechanical properties for bone tissue regeneration. Journal of Materials Chemistry B, 3(16), 3222-3233. doi:10.1039/c4tb01693aWu, Y., Shi, R., Chen, D., Zhang, L., & Tian, W. (2011). Nanosilica filled poly(glycerol-sebacate-citrate) elastomers with improved mechanical properties, adjustable degradability, and better biocompatibility. Journal of Applied Polymer Science, 123(3), 1612-1620. doi:10.1002/app.34556Liang, S.-L., Cook, W. D., Thouas, G. A., & Chen, Q.-Z. (2010). The mechanical characteristics and in vitro biocompatibility of poly(glycerol sebacate)-Bioglass® elastomeric composites. Biomaterials, 31(33), 8516-8529. doi:10.1016/j.biomaterials.2010.07.105Kokubo, T., & Takadama, H. (2006). How useful is SBF in predicting in vivo bone bioactivity? Biomaterials, 27(15), 2907-2915. doi:10.1016/j.biomaterials.2006.01.017Wahab, M. A., Kim, I., & Ha, C.-S. (2003). Microstructure and properties of polyimide/poly(vinylsilsesquioxane) hybrid composite films. Polymer, 44(16), 4705-4713. doi:10.1016/s0032-3861(03)00429-4Yan Song, X., Ping Geng, H., & Li, Q. F. (2006). The synthesis and characterization of polystyrene/magnetic polyhedral oligomeric silsesquioxane (POSS) nanocomposites. Polymer, 47(9), 3049-3056. doi:10.1016/j.polymer.2006.02.055Kerativitayanan, P., & Gaharwar, A. K. (2015). Elastomeric and mechanically stiff nanocomposites from poly(glycerol sebacate) and bioactive nanosilicates. Acta Biomaterialia, 26, 34-44. doi:10.1016/j.actbio.2015.08.025Liu, J., Zheng, H., Poh, P., Machens, H.-G., & Schilling, A. (2015). Hydrogels for Engineering of Perfusable Vascular Networks. International Journal of Molecular Sciences, 16(7), 15997-16016. doi:10.3390/ijms160715997Gibson, L. J., & Ashby, M. F. (1997). Cellular Solids. doi:10.1017/cbo9781139878326Vallés Lluch, A., Gallego Ferrer, G., & Monleón Pradas, M. (2009). Biomimetic apatite coating on P(EMA-co-HEA)/SiO2 hybrid nanocomposites. Polymer, 50(13), 2874-2884. doi:10.1016/j.polymer.2009.04.022Jones, J. R. (2006). Scaffolds for Cell and Tissue Engineering. Wiley Encyclopedia of Biomedical Engineering. doi:10.1002/9780471740360.ebs140

Injection laryngoplasty through a transoral approach using the Guedel oral airway

Le laringoplastiche iniettive hanno ottenuto notevole popolarità come modalità di trattamento per linsufficienza glottica. Numerosi approcci sono stati descritti: transcutaneo, transorale, transnasale. Gli autori descrivono una nuova tecnica, eseguita con successo in tre pazienti: la laringoplastica iniettiva endoscopica con lutilizzo la cannula di Guedel modificata. Cè stato un marcato miglioramento della disfonia, del tempo massimo fonatorio e del quoziente di chiusura glottica, insieme ad un decremento del Voice-Handicap Index-10 score. Questo nuovo valido approccio è applicabile per il trattamento dellinsufficienza glottica

Trend-based analysis of a population model of the AKAP scaffold protein

We formalise a continuous-time Markov chain with multi-dimensional discrete state space model of the AKAP scaffold protein as a crosstalk mediator between two biochemical signalling pathways. The analysis by temporal properties of the AKAP model requires reasoning about whether the counts of individuals of the same type (species) are increasing or decreasing. For this purpose we propose the concept of stochastic trends based on formulating the probabilities of transitions that increase (resp. decrease) the counts of individuals of the same type, and express these probabilities as formulae such that the state space of the model is not altered. We define a number of stochastic trend formulae (e.g. weakly increasing, strictly increasing, weakly decreasing, etc.) and use them to extend the set of state formulae of Continuous Stochastic Logic. We show how stochastic trends can be implemented in a guarded-command style specification language for transition systems. We illustrate the application of stochastic trends with numerous small examples and then we analyse the AKAP model in order to characterise and show causality and pulsating behaviours in this biochemical system

The role of lymphoid tissue SPARC in the pathogenesis and response to treatment of multiple myeloma.

BACKGROUND: Despite the significant progress in the treatment of multiple myeloma (MM), the disease remains untreatable and its cure is still an unmet clinical need. Neoplastic transformation in MM is initiated in the germinal centers (GCs) of secondary lymphoid tissue (SLT) where B cells experience extensive somatic hypermutation induced by follicular dendritic cells (FDCs) and T-cell signals. OBJECTIVE: We reason that secreted protein acidic and rich in cysteine (SPARC), a common stromal motif expressed by FDCs at the origin (SLTs) and the destination (BM) of MM, plays a role in the pathogenesis of MM, and, here, we sought to investigate this role. METHODS: There were 107 BM biopsies from 57 MM patients (taken at different time points) together with 13 control specimens assessed for SPARC gene and protein expression and compared with tonsillar tissues. In addition, regulation of myeloma-promoting genes by SPARC-secreting FDCs was assessed in in vitro GC reactions (GCRs). RESULTS: SPARC gene expression was confirmed in both human primary (BM) and secondary (tonsils) lymphoid tissues, and the expression was significantly higher in the BM. Sparc was detectable in the BM and tonsillar lysates, co-localized with the FDC markers in both tissues, and stimulation of FDCs in vitro induced significantly higher levels of SPARC expression than unstimulated controls. In addition, SPARC inversely correlated with BM PC infiltration, ISS staging, and ECOG performance of the MM patients, and in vitro addition of FDCs to lymphocytes inhibited the expression of several oncogenes associated with malignant transformation of PCs. CONCLUSION: FDC-SPARC inhibits several myelomagenic gene expression and inversely correlates with PC infiltration and MM progression. Therapeutic induction of SPARC expression through combinations of the current MM drugs, repositioning of non-MM drugs, or novel drug discovery could pave the way to better control MM in clinically severe and drug-resistant patients

Candida albicans quorum-sensing molecule farnesol modulates staphyloxanthin production and activates the thiol-based oxidative-stress response in Staphylococcus aureus

Microbial species utilize secreted-signaling molecules to coordinate their behavior. Our previous investigations demonstrated a key role for the Candida albicans-secreted quorum-sensing molecule farnesol in modulating Staphylococcus aureus response to antimicrobials in mixed biofilms. In this study, we aimed to provide mechanistic insights into the impact of farnesol on S. aureus within the context of inter-species interactions. To mimic biofilm dynamics, farnesol-sensitized S. aureus cells were generated via sequential farnesol exposure. The sensitized phenotype exhibited dramatic loss of the typical pigment, which we identified as staphyloxanthin, an important virulence factor synthesized by the Crt operon in S. aureus. Additionally, farnesol exposure exerted oxidative-stress as indicated by transcriptional analysis demonstrating alterations in redox-sensors and major virulence regulators. Paradoxically, the activated stress-response conferred S. aureus with enhanced tolerance to H2O2 and phagocytic killing. Since expression of enzymes in the staphyloxanthin biosynthesis pathway was not impacted by farnesol, we generated a theoretical-binding model which indicated that farnesol may block staphyloxanthin biosynthesis via competitive-binding to the CrtM enzyme crucial for staphyloxanthin synthesis, due to high structural similarity to the CrtM substrate. Finally, mixed growth with C. albicans was found to similarly induce S. aureus depigmentation, but not during growth with a farnesol-deficient C. albicans strain. Collectively, the findings demonstrate that a fungal molecule acts as a redox-cycler eliciting a bacterial stress response via activation of the thiol-based redox system under the control of global regulators. Therefore, farnesol-induced transcriptional modulations of key regulatory networks in S. aureus may modulate the pathogenesis of C. albicans- S. aureus co-infections

Simulation of Single and Twin Impinging Jets in Cross-flow of VTOL Aircrafts (Review)

When operating near the ground beneath a Vertical/Short Take-Off and Landing (VSTOL) aircraft a complex turbulent 3D flow is generated. This flow field can be represented by the configuration of twin impinging jets in a cross-flow. Studying these jets is a significant parameter for the design of VTOL aircraft. This flowfield during very low speed or hover flight operations is very complex and time dependent. An important number of experimental researches and simulations have been carried out to be able to understand much better these flows related with powered lift vehicles. Computational Fluid Dynamics (CFD) approach will be used in this paper work for simulation purposes of a single and twin impinging jet through and without crossflow