A Technical Note on Quantum Dots for Multi-Color Fluorescence in situ Hybridization

Quantum dots (Qdots) are semiconductor nanocrystals, which are photo-stable, show bright fluorescence with narrow, symmetric emission spectra and are available in multiple resolvable colors. We established a FISH protocol for the simultaneous visualization of up to 6 different DNA probes differentially labeled with Qdots and with conventional organic fluorochromes. Using a Leica SP5 laser scanning confocal microscope for image capture, we tested various combinations of hapten-labeled probes detected with streptavidin-Qdot525, sheep anti-digoxigenin-Qdot605, rat anti-dinitrophenyl-Qdot655 and goat anti-mouse-Qdot655, respectively, together with FITC-dUTP-, Cy3-dUTP- and Texas Red-dUTP-labeled probes. We further demonstrate that Qdots are suitable for imaging of FISH probes using 4Pi microscopy, which promises to push the resolution limits of light microscopy to 100 nanometers or less when applying a deconvolution algorithm, but requires the use of highly photo-stable fluors. Copyright (C) 2009 S. Karger AG, Base

Prolongation on regular infinitesimal flag manifolds

Many interesting geometric structures can be described as regular infinitesimal flag structures, which occur as the underlying structures of parabolic geometries. Among these structures we have for instance conformal structures, contact structures, certain types of generic distributions and partially integrable almost CR-structures of hypersurface type. The aim of this article is to develop for a large class of (semi-)linear overdetermined systems of partial differential equations on regular infinitesimal flag manifolds $M$ a conceptual method to rewrite these systems as systems of the form $\tilde\nabla(\Sigma)+C(\Sigma)=0$, where $\tilde\nabla$ is a linear connection on some vector bundle $V$ over $M$ and $C: V\rightarrow T^*M\otimes V$ is a (vector) bundle map. In particular, if the overdetermined system is linear, $\tilde\nabla+C$ will be a linear connection on $V$ and hence the dimension of its solution space is bounded by the rank of $V$. We will see that the rank of $V$ can be easily computed using representation theory.Comment: 35 pages; typos corrected and minor changes, final version to appear in International Journal of Mathematic

Palaeoecological analysis of two Late Pleistocene continental mollusc assemblages from Uruguay

Ponencia presentada en World Congress of Malacology, 1-5 Aug. 2022, Münich - Alemania, organizado por UNITAS Malacologica y Ludwig-Maximilians-Universität.Extant continental (freshwater and terrestrial) molluscs are very informative from an environmental point of view. The specific environmental requirements of different taxa can be extrapolated to the fossil assemblages in order to reconstruct past environments. This is especially true for the Quaternary, when fossil assemblages are mostly composed by extant species. We analysed two associations of continental molluscs from the Late Pleistocene of Uruguay, with the goal of reconstruct the depositional environments for each assemblage. For this analysis, 11 localities from the Sopas Formation and 10 from the Dolores Formation were selected. The statistical analyses aimed to understand the diversity of each locality and to make comparisons among them, using traditional diversity indices (Shannon, Simpson, Equitability). To estimate the diversity Rarefaction and Chao1 were applied. Lastly, the species occurrence in all localities were compared, using several multivariate analyses: NMDS with axes rotation by Principal Components Analysis, Correspondence Analysis, and Cluster Analysis. The multivariate analyses show that all local assemblages are distributed in two main associations: one composed mostly by Sopas Formation localities (Sopas Association) and the other composed mostly by Dolores Formation localities (Dolores Association). Only one locality from each Formation was interchanged. The Sopas Association records mostly the families Cyrenidae (36.1 %), Tateidae (32 %), Cochliopidae (26.1 %), and the only record of the family Chilinidae. Also, the large, massive species Diplodon charruanus, D. wymanii and D. peraeformis are present. Meanwhile, the Dolores Association records mostly representatives of Cochliopidae (54.4 %), Planorbinae (20.2 %), Sphaeridae (16 %), and has the only records of Physidae and Succineidae. Cochliopidae (Heleobia) are present in both associations, which is logical since currently they are quite ubiquitous in most lotic and lentic environments. Ampullariidae and the subfamily Ancylinae are also present in both associations, along with the delicate species Diplodon rhuacoicus, which is the only Diplodon from the Dolores Association. Presently, the communities that include Sopas-like assemblages are mostly found in high to moderate current lotic environments, with rocky to coarse bottoms. Meanwhile, the communities that include the taxa typical of the Dolores Association are common in lentic or very calm lotic environments, with fine sediments and abundant aquatic vegetation.ANII: FCE_3_2018_1_148922ANII: POS_NAC_2015_1_10947

A parametric study of the acoustic properties of thermal cladding systems

Thermal cladding systems have developed and modernised since the first systems were implemented, and predictions of single figure sound insulation improvement, ΔRW, based on the natural frequency, f0, of the spring-mass covering may no longer be reliable. To identify aspects of the compound acoustic behaviour due to multiple power flow paths of the thermal insulating system, a statistical energy analysis (SEA) based prediction model was developed. A simplified calculation of sound insulation improvement, ΔR, is described, allowing the high frequency (f > f0) behaviour of thermal cladding systems to be predicted. A parametric study in which the impact of different construction materials in the model is discussed; the damping constants, elastic properties of the interlayer and fixings, number of fixings, thickness and material properties (including bending stiffness) of the weatherproof outer layer and the heavyweight wall are assessed. While agreement within 4.0 dB (mean absolute differences) between calculated and measured results for thick render (≥8.0 mm) and curtain wall systems can be obtained at high frequencies (f > f0) using the simplified methodology, this approach was not successful at predicting single figure values. This is because single figure values are weighted towards the low frequencies. Correlation of calculated f0 with measured ΔRW is slightly improved (r.m.s. differences of 2.62 compared with 3.21 using the f0 calculation methodology in EN ISO12354 Annex D) when a modified method to calculate the combined stiffness is used. To improve predictions further, a methodology must be developed to obtain the transfer function, Ytr, used to calculate non-resonant coupling loss factor due to the spring-mass resonance of thermal cladding on the heavyweight wall. The mobility of the connections, Yc, should also be accurately characterised to ensure accurate predictions at high frequencies

Renovation and innovation using thermal insulation lining systems - Acoustic performance

Retrofit and design of thermal cladding systems provide an opportunity to improve the acoustic properties of a building. However, the complexity of the calculation process to predict sound insulation improvement may inhibit rather than encourage novelty and innovation. This paper investigates whether it is realistic to calculate the frequency dependant sound insulation improvement due to modern thermal insulation wall lining systems with just a few input parameters. The calculation procedure is tested using measured results for one external thermal insulation composite system (ETICS) and three curtain wall systems. The accuracy of the procedure is examined using three factors: (1) precision of the measurement, (2) variation of some of the basic parameters of the calculation procedure, and (3) an estimation of the standard error of the calculation. For the ETICS, agreement within <6.0 dB is achieved across much of the frequency range and the trend of the extended dip due to the spring-mass action of the panel is corroborated. The case for using this methodology on curtain wall systems is adequate, however, the trend of calculated results is mostly outside of the 95% confidence limits of the measured results. Possible reasons for this include lack of airtightness of all curtain wall systems and additional transmission due to radiation into and out of the cavity, neither of which are included in the model. The assumption of radiating points or lines, rather than a radiating surface involving the whole panel, gave better agreement at high frequencies for three of the four measured systems (f ≥ 2500 Hz)

Irradiation of benzene molecules by ion-induced and light-induced intense fields

Benzene, with its sea of delocalized $\pi$-electrons in the valence orbitals, is identified as an example of a class of molecules that enable establishment of the correspondence between intense ion-induced and laser-light-induced fields in experiments that probe ionization dynamics in temporal regimes spanning the attosecond and picosecond ranges.Comment: 4 ps figure

Interphase chromosome positioning in in vitro porcine cells and ex vivo porcine tissues

Copyright @ 2012 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and 85 reproduction in any medium, provided the original author and source are credited. The article was made available through the Brunel University Open Access Publishing Fund.BACKGROUND: In interphase nuclei of a wide range of species chromosomes are organised into their own specific locations termed territories. These chromosome territories are non-randomly positioned in nuclei which is believed to be related to a spatial aspect of regulatory control over gene expression. In this study we have adopted the pig as a model in which to study interphase chromosome positioning and follows on from other studies from our group of using pig cells and tissues to study interphase genome re-positioning during differentiation. The pig is an important model organism both economically and as a closely related species to study human disease models. This is why great efforts have been made to accomplish the full genome sequence in the last decade. RESULTS: This study has positioned most of the porcine chromosomes in in vitro cultured adult and embryonic fibroblasts, early passage stromal derived mesenchymal stem cells and lymphocytes. The study is further expanded to position four chromosomes in ex vivo tissue derived from pig kidney, lung and brain. CONCLUSIONS: It was concluded that porcine chromosomes are also non-randomly positioned within interphase nuclei with few major differences in chromosome position in interphase nuclei between different cell and tissue types. There were also no differences between preferred nuclear location of chromosomes in in vitro cultured cells as compared to cells in tissue sections. Using a number of analyses to ascertain by what criteria porcine chromosomes were positioned in interphase nuclei; we found a correlation with DNA content.This study is partly supported by Sygen International PLC

The radial arrangement of the human chromosome 7 in the lymphocyte cell nucleus is associated with chromosomal band gene density

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Springer-Verlag 2008.In the nuclei of human lymphocytes, chromosome territories are distributed according to the average gene density of each chromosome. However, chromosomes are very heterogeneous in size and base composition, and can contain both very gene-dense and very gene-poor regions. Thus, a precise analysis of chromosome organisation in the nuclei should consider also the distribution of DNA belonging to the chromosomal bands in each chromosome. To improve our understanding of the chromatin organisation, we localised chromosome 7 DNA regions, endowed with different gene densities, in the nuclei of human lymphocytes. Our results showed that this chromosome in cell nuclei is arranged radially with the gene-dense/GC-richest regions exposed towards the nuclear interior and the gene-poorest/GC-poorest ones located at the nuclear periphery. Moreover, we found that chromatin fibres from the 7p22.3 and the 7q22.1 bands are not confined to the territory of the bulk of this chromosome, protruding towards the inner part of the nucleus. Overall, our work demonstrates the radial arrangement of the territory of chromosome 7 in the lymphocyte nucleus and confirms that human genes occupy specific radial positions, presumably to enhance intra- and inter-chromosomal interaction among loci displaying a similar expression pattern, and/or similar replication timing