76 research outputs found
LightGuider: Guiding Interactive Lighting Design using Suggestions, Provenance, and Quality Visualization
LightGuider is a novel guidance-based approach to interactive lighting
design, which typically consists of interleaved 3D modeling operations and
light transport simulations. Rather than having designers use a trial-and-error
approach to match their illumination constraints and aesthetic goals,
LightGuider supports the process by simulating potential next modeling steps
that can deliver the most significant improvements. LightGuider takes
predefined quality criteria and the current focus of the designer into account
to visualize suggestions for lighting-design improvements via a specialized
provenance tree. This provenance tree integrates snapshot visualizations of how
well a design meets the given quality criteria weighted by the designer's
preferences. This integration facilitates the analysis of quality improvements
over the course of a modeling workflow as well as the comparison of alternative
design solutions. We evaluate our approach with three lighting designers to
illustrate its usefulness
An Automated Verification Workflow for Planned Lighting Setups using BIM
The use of Building Information Modeling (BIM) methods is becoming more and more established in the planning stage, during the construction, and for the management of buildings. Tailored BIM software packages allow to handle a vast amount of relevant aspects, but have so far not been covering specialized tasks like the evaluation of light distributions in and around a 3D model of a building. To overcome this limitation, we demonstrate the use of the open-source IFC format for preparing and exchanging BIM data to be used in our interactive light simulation system. By exploiting the availability of 3D data and semantic descriptions, it is possible to automatically place measurement surfaces in the 3D scene, and evaluate the suitability and sustainability of a planned lighting design according to given constraints and industry norms. Interactive visualizations for fast analysis of the simulation results, created using state-of-the-art web technologies, are seamlessly integrated in the 3D work environment, helping the lighting designer to quickly improve the initial lighting solution with a few clicks
Feature-assisted interactive geometry reconstruction in 3D point clouds using incremental region growing
Reconstructing geometric shapes from point clouds is a common task that is
often accomplished by experts manually modeling geometries in CAD-capable
software. State-of-the-art workflows based on fully automatic geometry
extraction are limited by point cloud density and memory constraints, and
require pre- and post-processing by the user. In this work, we present a
framework for interactive, user-driven, feature-assisted geometry
reconstruction from arbitrarily sized point clouds. Based on seeded
region-growing point cloud segmentation, the user interactively extracts planar
pieces of geometry and utilizes contextual suggestions to point out plane
surfaces, normal and tangential directions, and edges and corners. We implement
a set of feature-assisted tools for high-precision modeling tasks in
architecture and urban surveying scenarios, enabling instant-feedback
interactive point cloud manipulation on large-scale data collected from
real-world building interiors and facades. We evaluate our results through
systematic measurement of the reconstruction accuracy, and interviews with
domain experts who deploy our framework in a commercial setting and give both
structured and subjective feedback.Comment: 13 pages, submitted to Computers & Graphics Journa
Detailed Numerical Simulations on the Formation of Pillars around HII-regions
We study the structural evolution of turbulent molecular clouds under the
influence of ionizing radiation emitted from a nearby massive star by
performing a high resolution parameter study with the iVINE code. The
temperature is taken to be 10K or 100K, the mean number density is either
100cm^3 or 300cm^3. Besides, the turbulence is varied between Mach 1.5 and Mach
12.5 and the main driving scale between 1pc and 8pc. We vary the ionizing flux
by an order of magnitude. In our simulations the ionizing radiation enhances
the initial turbulent density distribution and thus leads to the formation of
pillar-like structures observed adjacent to HII regions in a natural way.
Gravitational collapse occurs regularly at the tips of the structures. We find
a clear correlation between the initial state of the turbulent cold cloud and
the final morphology and physical properties of the structures formed. The most
favorable regime for the formation of pillars is Mach 4-10. Structures and
therefore stars only form if the initial density contrast between the high
density unionized gas and the gas that is going to be ionized is lower than the
temperature contrast between the hot and the cold gas. The density of the
resulting pillars is determined by a pressure equilibrium between the hot and
the cold gas. A thorough analysis of the simulations shows that the complex
kinematical and geometrical structure of the formed elongated filaments
reflects that of observed pillars to an impressive level of detail. In
addition, we find that the observed line-of sight velocities allow for a
distinct determination of different formation mechanisms. Comparing the current
simulations to previous results and recent observations we conclude that e.g.
the pillars of creation in M16 formed by the mechanism proposed here and not by
the radiation driven implosion of pre-existing clumps.Comment: 15 pages, 12 figures, accepted for publication in Ap
Facile Synthesis of a Croconaine-Based Nanoformulation for Optoacoustic Imaging and Photothermal Therapy
Near-infrared (NIR) light absorbing theranostic agents can integrate optoacoustic imaging and photothermal therapy for effective personalized precision medicine. However, most of these agents face the challenges of unstable optical properties, material-associated toxicity, and nonbiodegradability, all of which limit their biomedical application. Several croconaine-based organic agents able to overcome some of these limitations have been recently reported, but these suffer from complicated multistep synthesis protocols. Herein, the use of CR760, a croconaine dye with excellent optical properties, is reported for nanoparticle formulation and subsequent optoacoustic imaging and photothermal therapy. Importantly, CR760 can be conveniently prepared in a single step from commercially available materials. Furthermore, CR760 can be covalently attached, via a polyethylene glycol linker, to the αvβ3 integrin ligand c(RGDyC), resulting in self-assembled nanoparticles (NPs) with cancer-targeting capability. Such CR760RGD-NPs exhibit strong NIR absorption, high photostability, high optoacoustic generation efficiency, and active tumor-targeting, making them ideal candidates for optoacoustic imaging. Due to favorable electron transfer, CR760RGD-NPs display a 45.37% photothermal conversion efficiency thereby rendering them additionally useful for photothermal therapy. Targeted tumor elimination, biosafety, and biocompatibility are demonstrated in a 4T1 murine breast tumor model. This work points to the use of CR760RGD-NPs as a promising nanoagent for NIR-based cancer phototheranostics
Modelling Shear Flows with SPH and Grid Based Methods
Given the importance of shear flows for astrophysical gas dynamics, we study
the evolution of the Kelvin-Helmholtz instability (KHI) analytically and
numerically. We derive the dispersion relation for the two-dimensional KHI
including viscous dissipation. The resulting expression for the growth rate is
then used to estimate the intrinsic viscosity of four numerical schemes
depending on code-specific as well as on physical parameters. Our set of
numerical schemes includes the Tree-SPH code VINE, an alternative SPH
formulation developed by Price (2008), and the finite-volume grid codes FLASH
and PLUTO. In the first part, we explicitly demonstrate the effect of
dissipation-inhibiting mechanisms such as the Balsara viscosity on the
evolution of the KHI. With VINE, increasing density contrasts lead to a
continuously increasing suppression of the KHI (with complete suppression from
a contrast of 6:1 or higher). The alternative SPH formulation including an
artificial thermal conductivity reproduces the analytically expected growth
rates up to a density contrast of 10:1. The second part addresses the shear
flow evolution with FLASH and PLUTO. Both codes result in a consistent
non-viscous evolution (in the equal as well as in the different density case)
in agreement with the analytical prediction. The viscous evolution studied with
FLASH shows minor deviations from the analytical prediction.Comment: 16 pages, 17 figure
Driving Turbulence and Triggering Star Formation by Ionizing Radiation
We present high resolution simulations on the impact of ionizing radiation of
massive O-stars on the surrounding turbulent interstellar medium (ISM). The
simulations are performed with the newly developed software iVINE which
combines ionization with smoothed particle hydrodynamics (SPH) and
gravitational forces. We show that radiation from hot stars penetrates the ISM,
efficiently heats cold low density gas and amplifies over-densities seeded by
the initial turbulence. The formation of observed pillar-like structures in
star forming regions (e.g. in M16) can be explained by this scenario. At the
tip of the pillars gravitational collapse can be induced, eventually leading to
the formation of low mass stars. Detailed analysis of the evolution of the
turbulent spectra shows that UV-radiation of O-stars indeed provides an
excellent mechanism to sustain and even drive turbulence in the parental
molecular cloud.Comment: 5 pages, 2 figures, accepted by ApJ Letter
miR-34a as hub of T cell regulation networks
Background: Micro(mi)RNAs are increasingly recognized as central regulators of immune cell function. While it has
been predicted that miRNAs have multiple targets, the majority of these predictions still await experimental confirmation.
Here, miR-34a, a well-known tumor suppressor, is analyzed for targeting genes involved in immune system processes of
leucocytes.
Methods: Using an in-silico approach, we combined miRNA target prediction with GeneTrail2, a web tool for Multi-omics
enrichment analysis, to identify miR-34a target genes, which are involved in the immune system process subcategory of
Gene Ontology.
Results: Out of the 193 predicted target genes in this subcategory we experimentally tested 22 target genes and
confirmed binding of miR-34a to 14 target genes including VAMP2, IKBKE, MYH9, MARCH8, KLRK1, CD11A, TRAFD1, CCR1,
PYDC1, PRF1, PIK3R2, PIK3CD, AP1B1, and ADAM10 by dual luciferase assays. By transfecting Jurkat, primary CD4+ and CD8+
T cells with miR-34a, we demonstrated that ectopic expression of miR-34a leads to reduced levels of endogenous VAMP2
and CD11A, which are central to the analyzed subcategories. Functional downstream analysis of miR-34a over-expression
in activated CD8+ T cells exhibits a distinct decrease of PRF1 secretion.
Conclusions: By simultaneous targeting of 14 mRNAs miR-34a acts as major hub of T cell regulatory networks suggesting
to utilize miR-34a as target of intervention towards a modulation of the immune responsiveness of T-cells in a broad
tumor context
Wrinkle in the plan: miR-34a-5p impacts chemokine signaling by modulating CXCL10/CXCL11/CXCR3-axis in CD4+, CD8+ T cells, and M1 macrophages
Background In 2016 the first-in-human phase I study of a miRNA-based cancer therapy with a liposomal mimic of microRNA-34a-5p (miR-34a-5p) was closed due to five immune related serious adverse events (SAEs) resulting in four patient deaths. For future applications of miRNA mimics in cancer therapy it is mandatory to unravel the miRNA effects both on the tumor tissue and on immune cells. Here, we set out to analyze the impact of miR-34a-5p over-expression on the CXCL10/CXCL11/CXCR3 axis, which is central for the development of an effective cancer control.
Methods We performed a whole genome expression analysis of miR-34a-5p transfected M1 macrophages followed by an over-representation and a protein–protein network analysis. In-silico miRNA target prediction and dual luciferase assays were used for target identification and verification. Target genes involved in chemokine signaling were functionally analyzed in M1 macrophages, CD4+ and CD8+ T cells.
Results A whole genome expression analysis of M1 macrophages with induced miR-34a-5p over-expression revealed an interaction network of downregulated target mRNAs including CXCL10 and CXCL11. In-silico target prediction in combination with dual luciferase assays identified direct binding of miR-34a-5p to the 3′UTRs of CXCL10 and CXCL11. Decreased CXCL10 and CXCL11 secretion was shown on the endogenous protein level and in the supernatant of miR-34a-5p transfected and activated M1 macrophages. To complete the analysis of the CXCL10/CXCL11/CXCR3 axis, we activated miR-34a-5p transfected CD4+ and CD8+ T cells by PMA/Ionomycin and found reduced levels of endogenous CXCR3 and CXCR3 on the cell surface.
Conclusions MiR-34a-5p mimic administered by intravenous administration will likely not only be up-taken by the tumor cells but also by the immune cells. Our results indicate that miR-34a-5p over-expression leads in M1 macrophages to a reduced secretion of CXCL10 and CXCL11 chemokines and in CD4+ and CD8+ T cells to a reduced expression of CXCR3. As a result, less immune cells will be attracted to the tumor site. Furthermore, high levels of miR-34a-5p in naive CD4+ T cells can in turn hinder Th1 cell polarization through the downregulation of CXCR3 leading to a less pronounced activation of cytotoxic T lymphocytes, natural killer, and natural killer T cells and possibly contributing to lymphocytopenia
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