Complex 3D Environments Research Articles

Creating Multiple Organotypic Models on a Single 3D Cell Culture Platform

BioTechniquesVol. 62, No. 3 Sponsored Paper - Application ForumOpen AccessCreating Multiple Organotypic Models on a Single 3D Cell Culture PlatformSei Hien Lim & Andrea PavesiSei Hien LimAIM Biotech Pte Lte, 51 Ayer Rajah Crescent #02-12/14, Singapore, 139948Search for more papers by this author & Andrea PavesiAIM Biotech Pte Lte, 51 Ayer Rajah Crescent #02-12/14, Singapore, 139948Search for more papers by this authorPublished Online:16 Mar 2018https://doi.org/10.2144/000114526AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinkedInReddit IntroductionIn vitro 3D cell culture models have emerged as a bridge between conventional 2D cell culture models and the complex & expensive in vivo animal models. By observing, analyzing and comparing the biological behavior of tissues embedded in 3 dimensional hydrogels, results are significantly different from the classic 2D cell culture. In particular, literature shows differences in terms of proliferation, morphology, drug response and gene expression [1–4]. These differences have been attributed to the topographically complex 3D environment surrounding the cells, where cell adhesion, structure, effector transport and mechanotransduction are substantially altered [5]. A carefully designed 3D model can therefore provide more physiologically relevant information using experimental designs unachievable by conventional 2D assays, at a fraction of the cost of in vivo models.Current 3D cell culture assays like hanging drop culture often lack the capability to organize different co-cultured cell types in a meaningful way. The application of chemical gradients or flow is usually not possible.We are now able to address this issue in a microfluidic platform (Figure 1a). The platform consists of a hydrogel channel and two flanking media channels, where cells can be meaningfully compartmentalized to study their interactions. The miniature posts that border the hydrogel channel maintain a vertical gel interface. Given the multi-channel design, a transient gradient of chemical factors can be set up across the hydrogel to yield a more physiologically relevant microenvironment.Materials and methodsCulture Cells in Media ChannelsFill polymerizable hydrogel (e.g. type I collagen, fibrin gel, Matrigel) into the gel channel (the middle channel shaded in red in Figure 1b). Once the gel has polymerized, fill cell culture medium into the media channels (the flanking channels shaded in blue in Figure 1b). Seed cells into the media channels. Set up chemical gradient across the gel region or apply flow in the channels, depending on your applications. Allow the cells to grow and interact with the microenvironment in an incubator. Observe the biological processes with phase contrast, fluorescent or confocal microscopy. Perform downstream analysis (e.g. ELISA, RT-PCR) on media or extracts collected from the chips to further understand the biological processes.Figure 1. A schematic drawing to illustrate (a) the three-channel design of the chip and the workflow for (b) culturing cells in media channels; (c) culturing cells in hydrogel and media channels.Table 1. Biological models that have been successfully created in the platform. Additional references to related publications can be found at http://www.aimbiotech.com/publications.htmlCulture Cells in Hydrogel ChannelsMix cell suspension or cell aggregates with the hydrogel of choice. Fill the hydrogel with cells into the gel channel. Once it has polymerized, fill cell culture medium into the media channels. Seed cells, of the same cell type or of a second cell type, into the media channels. Observe and study the biological processes as described above.ResultsDifferent biological models can be devised depending on the cell types and the locations of the cells being cultured. Cells (e.g. cancer cells) can be seeded in the media channels and be positioned at the gel interface for cell migration assays. With appropriate chemical gradients, the cells can invade into the 3D hydrogel and this process can be monitored in real time. Endothelial cells tend to form a monolayer in the media channel which itself is useful for permeability tests. In addition, with the appropriate angiogenic signals and interstitial flow, an endothelial monolayer can be induced to form sprouts in the 3D hydrogel and serve as an angiogenesis model. The same monolayer can also be co-cultured with tumor cells and be used to study transendothelial migration, i.e. extravasation or intravasation, depending on the location of the target cells.Endothelial cells mixed with fibrin gel will undergo morphogenesis to form vascular networks in the gel through vasculogenesis. The vascular networks can then be used for more advanced assays including flowing cells through the networks.Solid tumor dissemination can be modelled by seeding tumor cell aggregates in the hydrogel. Under the right culture conditions (with co-culture or stimuli), tumor cells will disseminate from the aggregates and invade the surrounding matrix, marking the first step of metastasis.Please visit www.AIMBiotech.com for more information.

Panthere V2: Multipurpose Simulation Software for 3D Dose Rate Calculations

PANTHERE is a multipurpose radiation protection software developed by EDF to calculate gamma dose rates in complex 3D environments. PANTHERE takes a key role in the EDF ALARA process, enabling to predict dose rates and to organize and optimize operations in high radiation environments. PANTHERE is also used for nuclear waste characterization, transport of nuclear materials, etc. It is used in most of the EDF engineering units and their design service providers and industrial partners.

DEVELOPING A 3D ROAD CADASTRAL SYSTEM: COMPARING LEGAL REQUIREMENTS AND USER NEEDS

Abstract. Road transport has always played an important role in a country’s growth and, in order to manage road networks and ensure a high standard of road performance (e.g. durability, efficiency and safety), both public and private road inventories have been implemented using databases and Geographical Information Systems. They enable registering and managing significant amounts of different road information, but to date do not focus on 3D road information, data integration and interoperability. In an increasingly complex 3D urban environment, and in the age of smart cities, however, applications including intelligent transport systems, mobility and traffic management, road maintenance and safety require digital data infrastructures to manage road data: thus new inventories based on integrated 3D road models (queryable, updateable and shareable on line) are required. This paper outlines the first step towards the implementation of 3D GIS-based road inventories. Focusing on the case study of the “Road Cadastre” (the Italian road inventory as established by law), it investigates current limitations and required improvements, and also compares the required data structure imposed by cadastral legislation with real road users’ needs. The study aims to: a) determine whether 3D GIS would improve road cadastre (for better management of data through the complete life-cycle infrastructure projects); b) define a conceptual model for a 3D road cadastre for Italy (whose general principles may be extended also to other countries).

The extracellular matrix: a new dimension in disease diagnosis and treatment

The extracellular matrix (ECM) forms the complex and dynamic 3D environment that defines tissue structure and function. Matrix molecules provide much of the microenvironmental plasticity that dictates cell behaviour, and their dysregulated expression is associated with a wide range of diseases including cancers, and inflammatory and fibrotic conditions. Here, we describe how these matrix molecules are beginning to be used for disease diagnosis and treatment.

Mathematical 3D modelling and sensitivity analysis of multipolar radiofrequency ablation in the spine

Radiofrequency ablation is a valuable tool in the treatment of many diseases, especially cancer. However, controlled heating up to apoptosis of the desired target tissue in complex situations, e.g. in the spine, is challenging and requires experienced interventionalists. For such challenging situations a mathematical model of radiofrequency ablation allows to understand, improve and optimise the outcome of the medical therapy. The main contribution of this work is the derivation of a tailored, yet expandable mathematical model, for the simulation, analysis, planning and control of radiofrequency ablation in complex situations. The dynamic model consists of partial differential equations that describe the potential and temperature distribution during intervention. To account for multipolar operation, time-dependent boundary conditions are introduced. Spatially distributed parameters, like tissue conductivity and blood perfusion, allow to describe the complex 3D environment representing diverse involved tissue types in the spine. To identify the key parameters affecting the prediction quality of the model, the influence of the parameters on the temperature distribution is investigated via a sensitivity analysis. Simulations underpin the quality of the derived model and the analysis approach. The proposed modelling and analysis schemes set the basis for intervention planning, state- and parameter estimation, and control.

A requirement for filopodia extension toward Slit during Robo-mediated axon repulsion.

Axons navigate long distances through complex 3D environments to interconnect the nervous system during development. Although the precise spatiotemporal effects of most axon guidance cues remain poorly characterized, a prevailing model posits that attractive guidance cues stimulate actin polymerization in neuronal growth cones whereas repulsive cues induce actin disassembly. Contrary to this model, we find that the repulsive guidance cue Slit stimulates the formation and elongation of actin-based filopodia from mouse dorsal root ganglion growth cones. Surprisingly, filopodia form and elongate toward sources of Slit, a response that we find is required for subsequent axonal repulsion away from Slit. Mechanistically, Slit evokes changes in filopodium dynamics by increasing direct binding of its receptor, Robo, to members of the actin-regulatory Ena/VASP family. Perturbing filopodium dynamics pharmacologically or genetically disrupts Slit-mediated repulsion and produces severe axon guidance defects in vivo. Thus, Slit locally stimulates directional filopodial extension, a process that is required for subsequent axonal repulsion downstream of the Robo receptor.

Simple change detection from mobile light field cameras

Vision tasks are complicated by the nonuniform apparent motion associated with dynamic cameras in complex 3D environments. We present a framework for light field cameras that simplifies dynamic-camera problems, allowing stationary-camera approaches to be applied. No depth estimation or scene modelling is required – apparent motion is disregarded by exploiting the scene geometry implicitly encoded by the light field. We demonstrate the strength of this framework by applying it to change detection from a moving camera, arriving at the surprising and useful result that change detection can be carried out with a closed-form solution. Its constant runtime, low computational requirements, predictable behaviour, and ease of parallel implementation in hardware including FPGA and GPU make this solution desirable in embedded application, e.g. robotics. We show qualitative and quantitative results for imagery captured using two generations of Lytro camera, with the proposed method generally outperforming both naive pixel-based methods and, for a commonly-occurring class of scene, state-of-the-art structure from motion methods. We quantify the tradeoffs between tolerance to camera motion and sensitivity to change, and the impact of coherent, widespread scene changes. Finally, we discuss generalization of the proposed framework beyond change detection, allowing classically still-camera-only methods to be applied in moving-camera scenarios.

An approach for real-time motion planning of an inchworm robot in complex steel bridge environments

SUMMARYPath planning can be difficult and time consuming for inchworm robots especially when operating in complex 3D environments such as steel bridges. Confined areas may prevent a robot from extensively searching the environment by limiting its mobility. An approach for real-time path planning is presented. This approach first uses the concept of line-of-sight (LoS) to find waypoints from the start pose to the end node. It then plans smooth, collision-free motion for a robot to move between waypoints using a 3D-F2algorithm. Extensive simulations and experiments are conducted in 2D and 3D scenarios to verify the approach.

Realtime emergency communication in virtual worlds

Purpose This paper aims to examine how media play a role in community responses to disaster. The authors explore how communication technology may allow new relationships between community groups and emergency agencies. The authors examine the context within which warnings and risk communication are interpreted by media services. The authors observe how, in an emergency context, the thinking about media may change from that of a linear framework of information provision to one of shared resources. Design/methodology/approach The authors focus on Second Life, a shared, online space which uses 3D graphic images to simulate a virtual environment. Second Life is posited as a media tool with clear advantages for the training of emergency services professionals and citizens in the community. The authors observe emergency training scenarios and advantages for training for critical thinking and decision-making. Findings The authors observe then how virtual worlds such as Second Life provide an online forum in which participants can interact, communicate and simulate action in a complex 3D graphic environment. Second Life may be a useful medium for simulating and testing geo-physical and social manoeuvres using the modeling tools. This may allow for collaborative decision-making in simulations which can prepare or rehearse people for emergency conditions. It may be useful in an emergency with information streamed and coordinated at a single online site. A shared network like Second Life may be shared by many people co-synchronously or a-synchronously, despite their geographic distance. Second Life applications may also be useful in the aftermath of emergencies for design and rebuilding, for analytical and educational purposes. Research limitations/implications It is clear that social networks like Second Life provide a valuable tool with which to learn about and share data and information about bushfires, community emergencies and safety precautions in a social setting. It can also provide, at the local level, a forum for community information and discussion, as well as for counselling and reconstruction in the aftermath. Practical implications The authors suggest that the range and flexibility of tools and their excellent geographic visualization and social networking functions may in future allow for learning and decision-making among diverse and disparate groups who can come together in virtual space. It is especially useful in remote communities as a means of uniting people who are otherwise isolated by distance or trapped in emergency situations. Second Life is useful for sharing information, organizational and local knowledge about disaster and mitigation management. This media-rich platform is valuable to a community that is increasingly adept with shared, 3D graphic computer interfaces. Social implications Applications like Second Life may provide a space where users can access a range of tools as a means of informing, educating, empowering and warning participants in emergency scenarios, both real and simulated. They are more than virtual spaces; they are also social spaces. A platform like Second Life may provide a virtual solution for such communication challenges especially where communities are too remote, too dispersed or even too many in number to be easily accessible in the field. Originality/value This paper contains new and significant information about emerging communication systems and platforms that may be of use to those researching and planning around disaster management, mitigation and resilience. It addresses the use of new techniques which are the result of innovation in technology, software design and network design. It applies a discussion of these techniques to several hypothetical and real-life scenarios to explore the potential for virtual tools as a way of providing enriched information, mapping and communication tools across a range of disaster response scenarios.

Designing dense connective tissues: identifying microenvironmental factors that direct human MSC differentiation in 3D

Event Abstract Back to Event Designing dense connective tissues: identifying microenvironmental factors that direct human MSC differentiation in 3D Jenna Usprech1 and Craig A. Simmons1, 2 1 University of Toronto, Institute of Biomaterials and Biomedical Engineering, Canada 2 University of Toronto, Department of Mechanical and Industrial Engineering, Canada Introduction: Microenvironmental factors such as biomaterial physical and biochemical properties, external mechanical stimuli, and soluble chemical cues integrate in vivo to direct the differentiation of mesenchymal stromal cells (MSCs). Identifying what factor combinations promote the differentiation of MSCs into myofibroblasts (the tissue producing cells of developing valves, ligaments, skin, tendons and periodontal ligaments) is a significant challenge when designing for dense, type I collagen-rich connective tissues. To date, select combinations of microenvironmental factors have been studied in 2D, but systematic consideration of the integration of factors in 3D culture has not been explored fully. Materials and Methods: We developed a 3D screening platform to systematically study MSC responses to microenvironmental stimuli. Permutations of the cell adhesion sequences RGD, DGEA and YIGSR at different concentrations (0-2 mM) were incorporated into 5-11 wt% (5-22 kPa compressive moduli) polyethylene glycol norbornene (PEG-NB) hydrogel arrays. Since PEG-NB is inert and easily crosslinked with UV light, adhesion ligands can be tuned independently from biomaterial properties, enabling us to identify the contribution of individual factors in a combinatorial fashion. Human bone marrow-derived MSCs were encapsulated and cultured in the 3D arrays for 7 days with 0 or 5 ng/mL TGF-β1. The extent of α-smooth muscle actin (αSMA) expression and collagen type I deposition were modeled using least squares estimation and regression on 3D confocal data (Figure 1A) that was analysed using Imaris (Figure 1B). Each experiment was replicated four times and statistical analyses were performed in JMP on the pooled data. Results and Discussion: Regression analyses of the screening data revealed that in the presence of TGF-β1, PEG-NB hydrogel wt% was the most significant factor influencing myofibroblast differentiation (p < 0.0001), with greater αSMA staining intensity manifesting at lower gel wt%. These data are in contrast to MSC myofibroblastic differentiation in 2D, which is promoted by stiffer substrates. With TGF-β1, RGD concentration was correlated with αSMA staining intensity in a positive, biphasic manner and demonstrated a significant, non-linear dependence with PEG-NB wt% (p = 0.02) (Figure 2A). Interestingly, αSMA staining intensity could only be predictably modeled by regression in cultures that were supplemented with TGF-β1. These observations suggest that while MSCs can express αSMA in the absence of exogenous TGF-β1, αSMA expression is only sensitive to material properties in the presence of TGF-β1. Collagen deposition was predominantly negatively correlated with PEG-NB hydrogel wt% (p<0.0001) with or without TGF-β1, with slight non-linear dependence between RGD and DGEA (p = 0.01) (Figure 2B) or linear dependence with RGD (p = 0.04) in the absence or presence of TGF-β1, respectively. Conclusion: The newly developed 3D screening platform enables the systematic identification of optimal conditions for connective tissue engineering when considering multiple interacting microenvironmental factors. The data presented here demonstrate that conditions which promote a myofibroblast phenotype in 2D do not translate completely to the more complex and integrative 3D environment. Keywords: Cell Differentiation, screening, 3D scaffold, instructive microenvironment Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: New Frontier Oral Topic: Biomaterials in constructing tissue substitutes Citation: Usprech J and Simmons CA (2016). Designing dense connective tissues: identifying microenvironmental factors that direct human MSC differentiation in 3D. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02714 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jenna Usprech Craig A Simmons Google Jenna Usprech Craig A Simmons Google Scholar Jenna Usprech Craig A Simmons PubMed Jenna Usprech Craig A Simmons Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Eye Tracking in the Wild: the Good, the Bad and the Ugly

Modelling human cognition and behaviour in rich naturalistic settings and under conditions of free movement of the head and body is a major goal of visual science. Eye tracking has turned out to be an excellent physiological means to investigate how we visually interact with complex 3D environments, real and virtual. This review begins with a philosophical look at the advantages (the Good) and the disadvantages (the Bad) in approaches with different levels of ecological naturalness (traditional tightly controlled laboratory tasks, low- and high-fidelity simulators, fully naturalistic real-world studies). We then discuss in more technical terms the differences in approach required “in the wild”, compared to “received” lab-based methods. We highlight how the unreflecting application of lab-based analysis methods, terminology, and tacit assumptions can lead to poor experimental design or even spurious results (the Ugly). The aim is not to present a “cookbook” of best practices, but to raise awareness of some of the special concerns that naturalistic research brings about. References to helpful literature are provided along the way. The aim is to provide an overview of the landscape from the point of view of a researcher planning serious basic research on the human mind and behaviour

Vinculin is required for cell polarization, migration, and extracellular matrix remodeling in 3D collagen.

Vinculin is filamentous (F)-actin-binding protein enriched in integrin-based adhesions to the extracellular matrix (ECM). Whereas studies in 2-dimensional (2D) tissue culture models have suggested that vinculin negatively regulates cell migration by promoting cytoskeleton-ECM coupling to strengthen and stabilize adhesions, its role in regulating cell migration in more physiologic, 3-dimensional (3D) environments is unclear. To address the role of vinculin in 3D cell migration, we analyzed the morphodynamics, migration, and ECM remodeling of primary murine embryonic fibroblasts (MEFs) with cre/loxP-mediated vinculin gene disruption in 3D collagen I cultures. We found that vinculin promoted 3D cell migration by increasing directional persistence. Vinculin was necessary for persistent cell protrusion, cell elongation, and stable cell orientation in 3D collagen, but was dispensable for lamellipodia formation, suggesting that vinculin-mediated cell adhesion to the ECM is needed to convert actin-based cell protrusion into persistent cell shape change and migration. Consistent with this finding, vinculin was necessary for efficient traction force generation in 3D collagen without affecting myosin II activity and promoted 3D collagen fiber alignment and macroscopical gel contraction. Our results suggest that vinculin promotes directionally persistent cell migration and tension-dependent ECM remodeling in complex 3D environments by increasing cell-ECM adhesion and traction force generation.

Rapid Quantification of 3D Collagen Fiber Alignment and Fiber Intersection Correlations with High Sensitivity.

Metastatic cancers aggressively reorganize collagen in their microenvironment. For example, radially orientated collagen fibers have been observed surrounding tumor cell clusters in vivo. The degree of fiber alignment, as a consequence of this remodeling, has often been difficult to quantify. In this paper, we present an easy to implement algorithm for accurate detection of collagen fiber orientation in a rapid pixel-wise manner. This algorithm quantifies the alignment of both computer generated and actual collagen fiber networks of varying degrees of alignment within 5°°. We also present an alternative easy method to calculate the alignment index directly from the standard deviation of fiber orientation. Using this quantitative method for determining collagen alignment, we demonstrate that the number of collagen fiber intersections has a negative correlation with the degree of fiber alignment. This decrease in intersections of aligned fibers could explain why cells move more rapidly along aligned fibers than unaligned fibers, as previously reported. Overall, our paper provides an easier, more quantitative and quicker way to quantify fiber orientation and alignment, and presents a platform in studying effects of matrix and cellular properties on fiber alignment in complex 3D environments.

Establishment of a human multiple myeloma xenograft model in the chicken to study tumor growth, invasion and angiogenesis.

Multiple myeloma (MM), a malignant plasma cell disease, remains incurable and novel drugs are required to improve the prognosis of patients. Due to the lack of the bone microenvironment and auto/paracrine growth factors human MM cells are difficult to cultivate. Therefore, there is an urgent need to establish proper in vitro and in vivo culture systems to study the action of novel therapeutics on human MM cells. Here we present a model to grow human multiple myeloma cells in a complex 3D environment in vitro and in vivo. MM cell lines OPM-2 and RPMI-8226 were transfected to express the transgene GFP and were cultivated in the presence of human mesenchymal cells and collagen type-I matrix as three-dimensional spheroids. In addition, spheroids were grafted on the chorioallantoic membrane (CAM) of chicken embryos and tumor growth was monitored by stereo fluorescence microscopy. Both models allow the study of novel therapeutic drugs in a complex 3D environment and the quantification of the tumor cell mass after homogenization of grafts in a transgene-specific GFP-ELISA. Moreover, angiogenic responses of the host and invasion of tumor cells into the subjacent host tissue can be monitored daily by a stereo microscope and analyzed by immunohistochemical staining against human tumor cells (Ki-67, CD138, Vimentin) or host mural cells covering blood vessels (desmin/ASMA). In conclusion, the onplant system allows studying MM cell growth and angiogenesis in a complex 3D environment and enables screening for novel therapeutic compounds targeting survival and proliferation of MM cells.

Formation Control in the scope of the MORPH project. Part I: Theoretical Foundations

We address the subject of formation control of underwater vehicles, using either inter-vehicle relative position measurements or range-only measurements. The work is motivated by the MORPH project, aiming at the use of formations of vehicles with complementary capabilities to map the underwater environment in complex 3D environments. The main problem studied is that of driving a vehicle (follower) to an appropriately defined position with respect to another vehicle (leader), which moves along a trajectory that is unknown to the follower. This control task is divided into two steps. Firstly, a trajectory-tracking controller is designed so that a follower vehicle can track a specified virtual target. Secondly, we design path-generators that yield the position and velocity of the virtual target to be tracked, for both the relative position measurements and the range-only measurements scenarios. These path-generation strategies take into account desirable formation behaviour and typical maneuver geometries. Applications to the MORPH project are presented. Finally, results of simulations are shown.

A cell-ECM screening method to predict breast cancer metastasis.

Breast cancer preferentially spreads to the bone, brain, liver, and lung. The clinical patterns of this tissue-specific spread (tropism) cannot be explained by blood flow alone, yet our understanding of what mediates tropism to these physically and chemically diverse tissues is limited. While the microenvironment has been recognized as a critical factor in governing metastatic colonization, the role of the extracellular matrix (ECM) in mediating tropism has not been thoroughly explored. We created a simple biomaterial platform with systematic control over the ECM protein density and composition to determine if integrin binding governs how metastatic cells differentiate between secondary tissue sites. Instead of examining individual behaviors, we compiled large patterns of phenotypes associated with adhesion to and migration on these controlled ECMs. In combining this novel analysis with a simple biomaterial platform, we created an in vitro fingerprint that is predictive of in vivo metastasis. This rapid biomaterial screen also provided information on how β1, α2, and α6 integrins might mediate metastasis in patients, providing insights beyond a purely genetic analysis. We propose that this approach of screening many cell-ECM interactions, across many different heterogeneous cell lines, is predictive of in vivo behavior, and is much simpler, faster, and more economical than complex 3D environments or mouse models. We also propose that when specifically applied toward the question of tissue tropism in breast cancer, it can be used to provide insight into certain integrin subunits as therapeutic targets.

Three-dimensional culture and FGF signaling drive differentiation of murine pluripotent cells to distal lung epithelial cells.

Reciprocal signaling between the lung mesenchyme and epithelium is crucial for differentiation and branching morphogenesis. We hypothesized that the combination of signaling pathways comprising early epithelial-mesenchymal interactions and a 3D spatial environment are necessary for an efficient induction of embryonic and induced pluripotent stem cells (ESCs and iPSCs) into a lung cell phenotype with hallmarks of the distal niche. Aggregating early, but not late, embryonic lung mesenchyme with endoderm-induced mouse ESCs and iPSCs for 6 days resulted in organization into tubular structures and differentiation of the tubular lining cells to an NKX2-1(+)/SOX2(-)/SOX9(+)/proSFTPC(+) lineage. Over 80% of the endoderm-induced cells committed to an NKX2-1(+) lineage. Electron microscopy analysis demonstrated numerous multivesicular bodies and glycogen deposits in the tubular lining cells, characteristic features of type II epithelial cell progenitors. Using soluble FGFR2 receptor antagonists, we demonstrate that reciprocal fibroblast growth factor (FGF) 2, 7, and 10 signaling is essential for differentiation of endoderm-induced cells to an NKX2-1(+)/proSFTPC(+) phenotype within 3D aggregates. Only FGF2 was able to commit endoderm-induced cells in monolayer cultures to an NKX2-1(+) lineage, however with a significant lower efficiency (∼16%) than seen with mesenchyme. Thus, while FGF2 signaling alone can induce a primed population of ESCs and iPSCs, the cells do not differentiate to distal lung epithelial progenitors with the same efficiency and level of maturity that is achieved when the complex tissue and 3D environment of the developing lung is more accurately recapitulated.

RF characterization of the substrate coupling noise between TSV and active devices in 3D integrated circuits

3D technology (TSVs, RDL, copper pillars) is gaining more and more interest. The functionalities and performances of the Wide I/O prototype (memory on logic 3D IC), developed by ST, ST-Ericson and CEA-LETI, was fully demonstrated. 3D process is mature enough to address next applications such as radiofrequency, analogic, and photonics. Nevertheless new challenges appear when 3D technology and these applications meet together. Particularly the parasitic electrical coupling of the TSV with active devices is a matter of interest and is investigated in this paper.Considering that the TSV will be a connection for several applications, characterized by a wide frequency domain, the signal transmission could generate substrate noise impacting MOS circuit operations. Noise coupling between TSV and active areas has to be characterized on a wide frequency range. The extraction of this coupling factor in the complex 3D circuit environment represents the bigger challenge of this study.An original strategy is proposed to investigate the coupling between TSVs and the complex MOS structure, consisting in splitting up the MOS into elementary wells with adequate doping conditions. It entailed innovative test structure design and definition of characterization method with RF and DC sources. The TSV under test is near different MOS wells and the noise coupling transfer factors were measured from 10MHz to 40GHz. They exhibit wide variations, increasing with frequency, from minimum −55dB to maximum −25dB. Variations according to the well implant and its applied polarization is also observed. It is explained by the presence of p-n junctions which is in agreement with an equivalent electrical model of structure.The sensitivity to substrate noise of PMOS and NMOS wells, standing for drain, source and bulk plug, were characterized and compared. TSV coupling with PMOS device is expected to be more critical than with NMOS. P+ plug is shown to be an efficient solution for substrate noise reduction.

Multimedia Presentation Integrating Media with Virtual 3D Realistic Environment Produced in Real Time with High Performance Processing

Sophisticated interactive animation may be an interesting element to compose a multimedia document. However, potential demand for high performance computing can make this option impractical in digital interactive TV and mobile device environments, due to computing power restrictions of such platforms, especially when one consider the processing of complex 3D environments with a high degree of realism. In previous work, we proposed a solution to overcome such restrictions based on video streaming. Moving forward, in this paper is presented a solution that is more independent of platform, but still based on the same principle of video streaming. Each module can be specialized in different ways to solve problems related to the computer environment, such as network restrictions and latency on user interaction. Also in this paper is described how to take advantage of media-agnostic feature of some multimedia presentation machines to integrate this type of complex 3D media into multimedia documents. As a proof of concept, we extended and tested an NCL presentation engine to add support to this new type of media.

PARALLEL HYBRID METAHEURISTIC ON SHARED MEMORY SYSTEM FOR REAL-TIME UAV PATH PLANNING

In this paper, we present a parallel hybrid metaheuristic that combines the strengths of the particle swarm optimization (PSO) and the genetic algorithm (GA) to produce an improved path-planner algorithm for fixed wing unmanned aerial vehicles (UAVs). The proposed solution uses a multi-objective cost function we developed and generates in real-time feasible and quasi-optimal trajectories in complex 3D environments. Our parallel hybrid algorithm simulates multiple GA populations and PSO swarms in parallel while allowing migration of solutions. This collaboration between the GA and the PSO leads to an algorithm that exhibits the strengths of both optimization methods and produces superior solutions. Moreover, by using the "single-program, multiple-data" parallel programming paradigm, we maximize the use of today's multicore CPU and significantly reduce the execution time of the parallel program compared to a sequential implementation. We observed a quasi-linear speedup of 10.7 times faster on a 12-core shared memory system resulting in an execution time of 5 s which allows in-flight planning. Finally, we show with statistical significance that our parallel hybrid algorithm produces superior trajectories to the parallel GA or the parallel PSO we previously developed.