Optical scatter of quantum noise filter cavity optics

Optical cavities to filter squeezed light for quantum noise reduction require optics with very low scattering losses. We report on measured light scattering from two super-polished fused silica optics before and after applying highly-reflective ion-beam sputtered dielectric coatings. We used an imaging scatterometer that illuminates the sample with a linearly polarized 1064 nm wavelength laser at a fixed angle of incidence and records images of back scatter for azimuthal angles in the plane of the laser beam. We extract from these images the bidirectional reflectance distribution function (BRDF) of the optics with and without coating and estimate their integrated scatter. We find that application of these coatings led to a more than 50% increase of the integrated wide-angle scatter, to 5.00+/-0.30 and 3.38+/-0.20 ppm for the two coated samples. In addition, the BRDF function of the coated optics takes on a pattern of maxima versus azimuthal angle. We compare with a scattering model to show that this is qualitatively consistent with roughness scattering from the coating layer interfaces. These results are part of a broader study to understand and minimize optical loss in quantum noise filter cavities for interferometric gravitational-wave detectors. The scattering measured for these samples is acceptable for the 16 m long filter cavities envisioned for the Laser Interferometer Gravitational-wave Observatory (LIGO), though reducing the loss further would improve LIGO's quantum-noise limited performance.Comment: 10 pages, 3 figure

Urotensin II-induced signaling involved in proliferation of vascular smooth muscle cells

The urotensin II receptor, bound by the ligand urotensin II, generates second messengers, ie, inositol triphosphate and diacylglycerol, which stimulate the subsequent release of calcium (Ca2+) in vascular smooth muscle cells. Ca2+ influx leads to the activation of Ca2+-dependent kinases (CaMK) via calmodulin binding, resulting in cellular proliferation. We hypothesize that urotensin II signaling in pulmonary arterial vascular smooth muscle cells (Pac1) and primary aortic vascular smooth muscle cells (PAVSMC) results in phosphorylation of Ca2+/calmodulin-dependent kinases leading to cellular proliferation. Exposure of Pac1 cultures to urotensin II increased intracellular Ca2+, subsequently activating Ca2+/calmodulin-dependent kinase kinase (CaMKK), and Ca2+/calmodulin-dependent kinase Type I (CaMKI), extracellular signal-regulated kinase (ERK 1/2), and protein kinase D. Treatment of Pac1 and PAVSMC with urotensin II increased proliferation as measured by 3H-thymidine uptake. The urotensin II-induced increase in 3H-thymidine incorporation was inhibited by a CaMKK inhibitor. Taken together, our results demonstrate that urotensin II stimulation of smooth muscle cells leads to a Ca2+/calmodulin-dependent kinase-mediated increase in cellular proliferation

Evidence for AGN Feedback in Galaxy Clusters and Groups

The current generation of flagship X-ray missions, Chandra and XMM-Newton, has changed our understanding of the so-called "cool core" galaxy clusters and groups. Instead of the initial idea that the thermal gas is cooling and flowing toward the center, the new picture envisages a complex dynamical evolution of the intra-cluster medium (ICM) regulated by the radiative cooling and the nongravitational heating from the active galactic nucleus (AGN). Understanding the physics of the hot gas and its interplay with the relativistic plasma ejected by the AGN is key for understanding the growth and evolution of galaxies and their central black holes, the history of star formation, and the formation of large-scale structures. It has thus become clear that the feedback from the central black hole must be taken into account in any model of galaxy evolution. In this paper, we draw a qualitative picture of the current knowledge of the effects of the AGN feedback on the ICM by summarizing the recent results in this field.Comment: Accepted for publication in Advances in Astronomy, 30 pages, 6 figures. Tutorial Review to appear in the Special Issue "Seeking for the Leading Actor on the Cosmic Stage: Galaxies versus Supermassive Black Holes

Progressive retinal degeneration and glial activation in the Cln6nclf mouse model of neuronal ceroid lipofuscinosis : a beneficial effect of DHA and Curcumin supplementation

Neuronal ceroid lipofuscinosis (NCL) is a group of neurodegenerative lysosomal storage disorders characterized by vision loss, mental and motor deficits, and spontaneous seizures. Neuropathological analyses of autopsy material from NCL patients and animal models revealed brain atrophy closely associated with glial activity. Earlier reports also noticed loss of retinal cells and reactive gliosis in some forms of NCL. To study this phenomenon in detail, we analyzed the ocular phenotype of CLN6nclf mice, an established mouse model for variant-late infantile NCL. Retinal morphometry, immunohistochemistry, optokinetic tracking, electroretinography, and mRNA expression were used to characterize retinal morphology and function as well as the responses of Müller cells and microglia. Our histological data showed a severe and progressive degeneration in the CLN6nclf retina co-inciding with reactive Müller glia. Furthermore, a prominent phenotypic transformation of ramified microglia to phagocytic, bloated, and mislocalized microglial cells was identified in CLN6nclf retinas. These events overlapped with a rapid loss of visual perception and retinal function. Based on the strong microglia reactivity we hypothesized that dietary supplementation with immuno-regulatory compounds, curcumin and docosahexaenoic acid (DHA), could ameliorate microgliosis and reduce retinal degeneration. Our analyses showed that treatment of three-week-old CLN6nclf mice with either 5% DHA or 0.6% curcumin for 30 weeks resulted in a reduced number of amoeboid reactive microglia and partially improved retinal function. DHA-treatment also improved the morphology of CLN6nclf retinas with a preserved thickness of the photoreceptor layer in most regions of the retina. Our results suggest that microglial reactivity closely accompanies disease progression in the CLN6nclf retina and both processes can be attenuated with dietary supplemented immuno-modulating compounds

A new methodology using beam elements for the analysis of steel frames subjected to non-uniform temperatures due to fires

[EN] Non-uniform heating in structures under fire involves the appearance of 3D-phenomena and typically requires the use of complex models built with finite elements shell or solid. Although different procedures have been developed to model the complex thermo-mechanical phenomenon, there is no simple, accurate, and low-cost computational methodology involving the space-time variation of the temperature and displacement fields that opens the path advancing more easily towards modeling more complex structural problems in a fire situation. To overcome this knowledge-gap, this paper presents a new methodology that fulfills those conditions, making it possible to carry out more complex analyses that require many simulations in a short time and at low computational costs. The new methodology to obtain the thermo-mechanical response to non-uniform heating and mechanical loads is general, simple, accurate, and avoids using complex and high-cost finite elements, simplifying the structural modeling, and reducing the computational analysis cost. As a result, complex structural fire engineering problems such as probabilistic and optimization analysis can be handled much more easily, representing a significant step toward the generalized application of performance-based approaches to deal with fire effects on structures. The procedure uses simple but advanced Timoshenko¿s beam-type finite elements and represents the non-uniform temperature space-time field through a mean value of the temperature and the two mean values of the section thermal gradients which are variable in time during the fire. The methodology is satisfactorily validated with results (experimental and numerical) of the Cardington frame test and captures 3D-phenomena such as buckling, flexural-torsional buckling, and warping.Thanks are due to the Fundación Carolina, the Universitat Politècnica de València, and the Universidad Surcolombiana for the support given to this research through the 2018-2019 Ph.D. scholarship.Pallares-Muñoz, MR.; Paya-Zaforteza, I.; Hospitaler Pérez, A. (2021). A new methodology using beam elements for the analysis of steel frames subjected to non-uniform temperatures due to fires. Structures. 31:462-483. https://doi.org/10.1016/j.istruc.2021.02.008S46248331Shan, S., & Li, S. (2020). Fire-induced progressive collapse mechanisms of steel frames with partial infill walls. Structures, 25, 347-359. doi:10.1016/j.istruc.2020.03.023Shakib, H., Zakersalehi, M., Jahangiri, V., & Zamanian, R. (2020). Evaluation of Plasco Building fire-induced progressive collapse. Structures, 28, 205-224. doi:10.1016/j.istruc.2020.08.058Horová, K., Jána, T., & Wald, F. (2013). Temperature heterogeneity during travelling fire on experimental building. Advances in Engineering Software, 62-63, 119-130. doi:10.1016/j.advengsoft.2013.05.001Xu, L., & Zhuang, Y. (2012). Storey-based stability of unbraced steel frames at elevated temperature. Journal of Constructional Steel Research, 78, 79-87. doi:10.1016/j.jcsr.2012.06.010Jacques, L., Béchet, E., & Kerschen, G. (2017). Finite element model reduction for space thermal analysis. Finite Elements in Analysis and Design, 127, 6-15. doi:10.1016/j.finel.2017.01.001B.D. R, M. SK. Behaviour of steel columns with realistic boundary restraints under standard fire. Structures 2020;28:626–37. https://doi.org/https://doi.org/10.1016/j.istruc.2020.08.028.Alos-Moya, J., Paya-Zaforteza, I., Hospitaler, A., & Loma-Ossorio, E. (2019). Valencia bridge fire tests: Validation of simplified and advanced numerical approaches to model bridge fire scenarios. Advances in Engineering Software, 128, 55-68. doi:10.1016/j.advengsoft.2018.11.003Jeffers, A. E., & Beata, P. A. (2014). Generalized shell heat transfer element for modeling the thermal response of non-uniformly heated structures. Finite Elements in Analysis and Design, 83, 58-67. doi:10.1016/j.finel.2014.01.003Rigobello, R., Coda, H. B., & Munaiar Neto, J. (2014). A 3D solid-like frame finite element applied to steel structures under high temperatures. Finite Elements in Analysis and Design, 91, 68-83. doi:10.1016/j.finel.2014.07.005Alos-Moya, J., Paya-Zaforteza, I., Hospitaler, A., & Rinaudo, P. (2017). Valencia bridge fire tests: Experimental study of a composite bridge under fire. Journal of Constructional Steel Research, 138, 538-554. doi:10.1016/j.jcsr.2017.08.008Peris-Sayol, G., Paya-Zaforteza, I., Alos-Moya, J., & Hospitaler, A. (2015). Analysis of the influence of geometric, modeling and environmental parameters on the fire response of steel bridges subjected to realistic fire scenarios. Computers & Structures, 158, 333-345. doi:10.1016/j.compstruc.2015.06.003Quiel, S. E., Moreyra Garlock, M. E., & Paya-Zaforteza, I. (2011). Closed-Form Procedure for Predicting the Capacity and Demand of Steel Beam-Columns under Fire. Journal of Structural Engineering, 137(9), 967-976. doi:10.1061/(asce)st.1943-541x.0000443Davidson, M. T., Harik, I. E., & Davis, D. B. (2013). Fire Impact and Passive Fire Protection of Infrastructure: State of the Art. Journal of Performance of Constructed Facilities, 27(2), 135-143. doi:10.1061/(asce)cf.1943-5509.0000295Allam, A., Nassif, A., & Nadjai, A. (2019). Behaviour of restrained steel beam at elevated temperature – parametric studies. Journal of Structural Fire Engineering, 10(3), 324-339. doi:10.1108/jsfe-11-2018-0036Santiago A, Haremza C, Simões da Silva L, Rodrigues JP. Numerical behaviour of steel columns subject to localized fire loading. In: Topping BH V., Costa Neves LF, Barros RC, editors. Proc. Twelfth Int. Conf. Civil, Struct. Environ. Eng. Comput., Stirlingshire, Scotland: Civil-Comp Press; 2009.Burges I, Alexandrou M. Composite beams. In: Ed. Wald F, Burgess I, Kwasniewski L, Horová K, Caldová E, editors. Benchmark Stud. Verif. Numer. Model. fire Eng. 1st ed., Prague: CTU Publishing House; 2014.Burges I, Alexandrou M. Steel beams. In: Ed. Wald F, Burgess I, Kwasniewski L, Horová K, Caldová E, editors. Benchmark Stud. Verif. Numer. Model. fire Eng. 1st ed., Prague: CTU Publishing House; 2014.Burgess I, Plank R, Shephered P. Vulcan 2019.Santiago A, Haremza C, Lopes F, Franssen JM. Numerical behaviour of steel columns under localized fire loading. In: Ed. Wald F, Burgess I, Kwasniewski L, Horová K, Caldová E, editors. Benchmark Stud. Exp. Valid. Numer. Model. fire Eng. 1st ed., Prague: CTU Publishing House; 2014.Franssen, J. M., Cooke, G. M. E., & Latham, D. J. (1995). Numerical simulation of a full scale fire test on a loaded steel framework. Journal of Constructional Steel Research, 35(3), 377-408. doi:10.1016/0143-974x(95)00010-sSrivastava, G., & Ravi Prakash, P. (2017). An integrated framework for nonlinear analysis of plane frames exposed to fire using the direct stiffness method. Computers & Structures, 190, 173-185. doi:10.1016/j.compstruc.2017.05.013EN 1993-1-2. Eurocode 3: Design of steel structures - Part 1-2: General rules - Structural fire design. Brussels: European Committee for Standardization; 2005.EN 1992-1-2. Eurocode 2: Design of concrete structures - Part 1-2: General rules - Structural fire design. Brussels: European Committee for Standardization; 2004.Purkiss JA, Li LY. Fire safety engineering design of structures. 3rd Editio. Boca Raton: CRC Press; 2013. https://doi.org/10.1201/b16059.Ansys. ANSYS Engineering Analysis System. User manual. Canonsburg, Pensilvania: Houston, Pa. : Swanson Analysis Systems, 2019; 2019.Oñate E. Structural Analysis with the Finite Element Method Linear Statics: Volume 2. Beams, Plates and Shells. 1st ed. Barcelona: Springer; 2013.Magisano, D., Liguori, F., Leonetti, L., de Gregorio, D., Zuccaro, G., & Garcea, G. (2019). A quasi-static nonlinear analysis for assessing the fire resistance of reinforced concrete 3D frames exploiting time-dependent yield surfaces. Computers & Structures, 212, 327-342. doi:10.1016/j.compstruc.2018.11.005Kiakojouri, F., De Biagi, V., Chiaia, B., & Sheidaii, M. R. (2020). Progressive collapse of framed building structures: Current knowledge and future prospects. Engineering Structures, 206, 110061. doi:10.1016/j.engstruct.2019.11006

RAWUL: A new ubiquitin-like domain in PRC1 Ring finger proteins that unveils putative plant and worm PRC1 orthologs

<p>Abstract</p> <p>Background</p> <p>Polycomb group (PcG) proteins are a set of chromatin-modifying proteins that play a key role in epigenetic gene regulation. The PcG proteins form large multiprotein complexes with different activities. The two best-characterized PcG complexes are the PcG repressive complex 1 (PRC1) and 2 (PRC2) that respectively possess histone 2A lysine 119 E3 ubiquitin ligase and histone 3 lysine 27 methyltransferase activities. While PRC2-like complexes are conserved throughout the eukaryotic kingdoms, PRC1-like complexes have only been described in Drosophila and vertebrates. Since both complexes are required for the gene silencing mechanism in Drosophila and vertebrates, how PRC1 function is realized in organisms that apparently lack PRC1 such as plants, is so far unknown. In vertebrates, PRC1 includes three proteins, Ring1B, Ring1A, and Bmi-1 that form an E3 ubiquitin ligase complex. These PRC1 proteins have an N-terminally located Ring finger domain associated to a poorly characterized conserved C-terminal region.</p> <p>Results</p> <p>We obtained statistically significant evidences of sequence similarity between the C-terminal region of the PRC1 Ring finger proteins and the ubiquitin (Ubq)-like family proteins, thus defining a new Ubq-like domain, the RAWUL domain. In addition, our analysis revealed the existence of plant and worm proteins that display the conserved combination of a Ring finger domain at the N-terminus and a RAWUL domain at the C-terminus.</p> <p>Conclusion</p> <p>Analysis of the conserved domain architecture among PRC1 Ring finger proteins revealed the existence of long sought PRC1 protein orthologs in these organisms, suggesting the functional conservation of PRC1 throughout higher eukaryotes.</p

New modeling strategies for analyzing lateral-torsional buckling in class-4 steel structural members at elevated temperatures using beam-type elements

[EN] Fire is one of the main hazards that can affect steel buildings and bridges and was responsible, e.g., for the collapse of the Plasco building in Tehran, Iran, and the I-65 bridge in Birmingham, Alabama, USA. This vulnerability has motivated the development of advanced computational models to predict the response of steel structures to fire accurately. The mechanical response of slender steel members to fire is especially important because they fail prematurely by buckling at load values below their elastic strength. However, the structural analysis of these members typically requires advanced and complex FE models with shell elements, including initial geometric and material imperfections. These shell models are computationally expensive, complicating the carrying out of parametric and probabilistic studies. Therefore, there is a need to develop simple, accurate, and low-cost computational models as reliable as shell-type models. To overcome this knowledge gap, this paper presents two new modeling strategies that simulate the mechanical response of class-4 steel members subjected to lateral-torsional buckling in fire using Timoshenko beam-type finite elements, which significantly simplify the structural modeling. These strategies are called Fiber Beam Model (FBM) and Cruciform Frame Model (CFM) and include initial geometric and material imperfections and thermal strains. In the FBM, the steel member is represented by a single fiber of I-section beam elements, whereas in the CFM, a cruciform arrangement of rectangular beam finite element fibers idealizes it, making the CFM more complex to build than FBM. Both strategies were satisfactorily validated with experimental and numerical results of Test-1 and Test-3 carried out in the ¿Fire design of steel members with welded or hot-rolled class-4 cross-section¿ (FIDESC4) research project on a slender beam of class-4 section. Although both FBM and CFM correctly captured the LTB resistance of the tested beam, CFM can, in addition, adequately reproduce the local buckling failure and significantly reduced the computational time. That means complex fire engineering problems such as probabilistic and optimization analyses of thin-walled beams can be addressed more easily and accurately, representing an important step towards applying performance-based approaches in slender steel structures under fire.Thanks are due to the Fundacion Carolina for the support given to this research through a Ph.D. scholarship.Pallares-Muñoz, MR.; Paya-Zaforteza, I.; Hospitaler Pérez, A. (2021). New modeling strategies for analyzing lateral-torsional buckling in class-4 steel structural members at elevated temperatures using beam-type elements. Structures. 34:3508-3532. https://doi.org/10.1016/j.istruc.2021.09.087S350835323