Cemeteries Are Effective Sites For Monitoring La Crosse Virus (LACv) and these Environments May Play a Role in LACv Infection

La Crosse encephalitis (LAC) is the leading arboviral disease among children, and was previously limited to the upper Midwest. In 2012 nine pediatric cases of LAC occurred in eastern Tennessee, including one fatal case. In an attempt to identify sites near an active LACv infection and describe the abundance and distribution of potential LACv vectors near a fatal LAC case in the Appalachian region, we initiated an end of season study using a combination of questing and oviposition mosquito traps placed at forty-nine sites consisting of cemeteries and houses within 16 radial kilometers of two pediatric infections. LACv was isolated from threeAedes triseriatus pools collected from cemeteries and spatial clustering analysis identified clusters of Ae. triseriatus and Ae. albopictus populations that overlapped in the same area as the 2012 LACv cases. Results indicate cemeteries are effective sites for monitoring LACv. The role of cemeteries and specific environmental features will be the focus of future investigations

Habitat and Vegetation Variables Are Not Enough When Predicting Tick Populations in the Southeastern United States

La Crosse encephalitis (LAC) is the leading arboviral disease among children, and was previously limited to the upper Midwest. In 2012 nine pediatric cases of LAC occurred in eastern Tennessee, including one fatal case. In an attempt to identify sites near an active LACv infection and describe the abundance and distribution of potential LACv vectors near a fatal LAC case in the Appalachian region, we initiated an end of season study using a combination of questing and oviposition mosquito traps placed at forty-nine sites consisting of cemeteries and houses within 16 radial kilometers of two pediatric infections. LACv was isolated from three Aedes triseriatus pools collected from cemeteries and spatial clustering analysis identified clusters of Ae. triseriatus and Ae. albopictus populations that overlapped in the same area as the 2012 LACv cases. Results indicate cemeteries are effective sites for monitoring LACv. The role of cemeteries and specific environmental features will be the focus of future investigations

ELECTROPHORETIC DISPLAYS WITH TUNABLE, ANGLE-INDEPENDENT COLOR

Electrophoretic displays (EPDs), which exploit the surface charge of microparticles to control their deposition, have become widely available in consumer electronics, such as e-readers and smartwatches. However, a full-color EPD has yet to be demonstrated and commercialized. Here, we demonstrate colloidal assemblies of engineered quasi-amorphous photonic materials, using pigmentary α-Fe2O3/SiO2 core/shell nanoparticles, exhibiting non- iridescent tunable colors which can be tuned electrophoretically. The observed colors result from combination of colloidal particle arrangements, giving rise to structural color, along with the inherent pigmentary color of the α-Fe2O3/SiO2 nanoparticles. Colloidal particle assemblies of α-Fe2O3/SiO2 core/shell nanoparticles, and therefore the resulting colors, can be manipulated by shell thickness, particle concentration and external electrical stimuli. Dynamic tunability of α-Fe2O3/SiO2 nanomaterials in the visible wavelengths is demonstrated using reversible electrophoretic deposition with a noticeable difference between transmitted and reflected colors. The distinct contrast generated can be exploited for tunable display applications. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-704082

On occurrence of spectral edges for periodic operators inside the Brillouin zone

The article discusses the following frequently arising question on the spectral structure of periodic operators of mathematical physics (e.g., Schroedinger, Maxwell, waveguide operators, etc.). Is it true that one can obtain the correct spectrum by using the values of the quasimomentum running over the boundary of the (reduced) Brillouin zone only, rather than the whole zone? Or, do the edges of the spectrum occur necessarily at the set of ``corner'' high symmetry points? This is known to be true in 1D, while no apparent reasons exist for this to be happening in higher dimensions. In many practical cases, though, this appears to be correct, which sometimes leads to the claims that this is always true. There seems to be no definite answer in the literature, and one encounters different opinions about this problem in the community. In this paper, starting with simple discrete graph operators, we construct a variety of convincing multiply-periodic examples showing that the spectral edges might occur deeply inside the Brillouin zone. On the other hand, it is also shown that in a ``generic'' case, the situation of spectral edges appearing at high symmetry points is stable under small perturbations. This explains to some degree why in many (maybe even most) practical cases the statement still holds.Comment: 25 pages, 10 EPS figures. Typos corrected and a reference added in the new versio

The contribution of visual information to the perception of speech in noise with and without informative temporal fine structure

Understanding what is said in demanding listening situations is assisted greatly by looking at the face of a talker. Previous studies have observed that normal-hearing listeners can benefit from this visual information when a talker’s voice is presented in background noise. These benefits have also been observed in quiet listening conditions in cochlear-implant users, whose device does not convey the informative temporal fine structure cues in speech, and when normal-hearing individuals listen to speech processed to remove these informative temporal fine structure cues. The current study (1) characterised the benefits of visual information when listening in background noise; and (2) used sine-wave vocoding to compare the size of the visual benefit when speech is presented with or without informative temporal fine structure. The accuracy with which normal-hearing individuals reported words in spoken sentences was assessed across three experiments. The availability of visual information and informative temporal fine structure cues was varied within and across the experiments. The results showed that visual benefit was observed using open- and closed-set tests of speech perception. The size of the benefit increased when informative temporal fine structure cues were removed. This finding suggests that visual information may play an important role in the ability of cochlear-implant users to understand speech in many everyday situations. Models of audio-visual integration were able to account for the additional benefit of visual information when speech was degraded and suggested that auditory and visual information was being integrated in a similar way in all conditions. The modelling results were consistent with the notion that audio-visual benefit is derived from the optimal combination of auditory and visual sensory cues

Decomposition cross-correlation for analysis of collagen matrix deformation by single smooth muscle cells

Microvascular remodeling is known to depend on cellular interactions with matrix tissue. However, it is difficult to study the role of specific cells or matrix elements in an in vivo setting. The aim of this study is to develop an automated technique that can be employed to obtain and analyze local collagen matrix remodeling by single smooth muscle cells. We combined a motorized microscopic setup and time-lapse video microscopy with a new cross-correlation based image analysis algorithm to enable automated recording of cell-induced matrix reorganization. This method rendered 60–90 single cell studies per experiment, for which collagen deformation over time could be automatically derived. Thus, the current setup offers a tool to systematically study different components active in matrix remodeling

Computational methodology to determine fluid related parameters on non regular three-dimensional scaffolds

The application of three-dimensional (3D) biomaterials to facilitate the adhesion, proliferation, and differentiation of cells has been widely studied for tissue engineering purposes. The fabrication methods used to improve the mechanical response of the scaffold produce complex and non regular structures. Apart from the mechanical aspect, the fluid behavior in the inner part of the scaffold should also be considered. Parameters such as permeability (k) or wall shear stress (WSS) are important aspects in the provision of nutrients, the removal of metabolic waste products or the mechanically-induced differentiation of cells attached in the trabecular network of the scaffolds. Experimental measurements of these parameters are not available in all labs. However, fluid parameters should be known prior to other types of experiments. The present work compares an experimental study with a computational fluid dynamics (CFD) methodology to determine the related fluid parameters (k and WSS) of complex non regular poly(L-lactic acid) scaffolds based only on the treatment of microphotographic images obtained with a microCT (lCT). The CFD analysis shows similar tendencies and results with low relative difference compared to those of the experimental study, for high flow rates. For low flow rates the accuracy of this prediction reduces. The correlation between the computational and experimental results validates the robustness of the proposed methodology.The authors gratefully acknowledge research support from the Spanish Ministry of Science and Innovation through research project DPI2010-20399-C04-01. The Instituto de Salud Carlos III (ISCIII) through the CIBER initiative and the Platform for Biological Tissue Characterization of the Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN) are also gratefully acknowledged.Acosta Santamaría, VA.; Malvé, M.; Duizabo, A.; Mena Tobar, A.; Gallego Ferrer, G.; García Aznar, J.; Doblare Castellano, M.... (2013). Computational methodology to determine fluid related parameters on non regular three-dimensional scaffolds. Annals of Biomedical Engineering. 41(11):2367-2380. https://doi.org/10.1007/s10439-013-0849-8S236723804111Acosta Santamaría, V., H. Deplaine, D. Mariggió, A. R. Villanueva-Molines, J. M. García-Aznar, J. L. Gómez Ribelles, M. Doblaré, G. Gallego Ferrer, and I. Ochoa. Influence of the macro and micro-porous structure on the mechanical behavior of poly(l-lactic acid) scaffolds. J. Non-Cryst. Solids 358(23):3141–3149, 2012.Adachi, T., Y. Osako, M. Tanaka, M. Hojo, and S. J. Hollister. Framework for optimal design of porous scaffold microstructure by computational simulation of bone regeneration. Biomaterials 27(21):3964–3972, 2006.Adamczyk, Z., and T. G. M. Vandeven. Deposition of particles under external forces in laminar-flow through parallel-plate and cylindrical channels. J. Colloid Interface Sci. 80(2):340–356, 1981.Alberich, B. A., D. Moratal, J. L. Escobar, J. C. Rodríguez, A. Vallés-Lluch, L. Martí-Bonmatí, et al. Microcomputed tomography and microfinite element modeling for evaluating polymer scaffolds architecture and their mechanical properties. J. Biomed. Mater. Res. B Appl. Biomater. 91B(1):191–202, 2009.Al-Munajjed, A., M. Hien, R. Kujat, J. P. Gleeson, and J. Hammer. Influence of pore size on tensile strength, permeability and porosity of hyaluronan-collagen scaffolds. J. Mater. Sci. Mater. Med. 19(8):2859–2864, 2008.Alves da Silva, M. L., A. Martins, A. R. Costa-Pinto, V. M. Correlo, P. Sol, M. Bhattacharya, S. Faria, R. L. Reis, and N. M. Neves. Chondrogenic differentiation of human bone marrow mesenchymal stem cells in chitosan-based scaffolds using a flow-perfusion bioreactor. J. Tissue Eng. Regen. Med. 5(9):722–732, 2011.Ansys (2010) CFX Theory User Manual. Canonsburg, PA: Ansys Software.Brígido, R. D., J. M. Estellés, J. A. Sanz, J. M. García-Aznar, and M. S. Sánchez. Polymer scaffolds with interconnected spherical pores and controlled architecture for tissue engineering: fabrication, mechanical properties, and finite element modeling. J. Biomed. Mater. Res. B Appl. Biomater. 81B(2):448–455, 2007.Byrne, P. D., D. Lacroix, J. A. Planell, D. J. Kelly, and P. J. Prendergast. Simulation of tissue differentiation in a scaffold as a function of porosity, Young’s modulus and dissolution rate: application of mechanobiological models in tissue engineering. Biomaterials 28:5544–5554, 2007.Chor, M. V., and W. Li. A permeability measurement system for tissue engineering scaffolds. Meas. Sci. Technol. 18(1):208–216, 2007.Cozensroberts, C., J. A. Quinn, and D. A. Lauffenburger. Receptor-mediated adhesion phenomena—model studies with the radial-flow detachment assay. Biophys. J. 58(1):107–125, 1990.Davisson, T., R. L. Sah, and A. Ratcliffe. Perfusion increases cell content and matrix synthesis in chondrocyte three-dimensional cultures. Tissue Eng. 8(5):807–816, 2002.Deplaine, H., M. Lebourg, P. Ripalda, A. Vidaurre, P. Sanz-Ramos, G. Mora, F. Prósper, I. Ochoa, M. Doblaré, J. L. Gómez Ribelles, I. Izal-Azcárate, and G. Gallego Ferrer. Biomimetic hydroxyapatite coating on pore walls improves osteointegration of poly(l-lactic acid) scaffolds. J. Biomed. Mater. Res. B Appl. Biomater. 101(1):173–186, 2013.Dias, M. R., P. R. Fernandes, J. M. Guedes, and S. J. Hollister. Permeability analysis of scaffolds for bone tissue engineering. J. Biomech. 45(6):938–944, 2012.Freyman, T. M., I. V. Yannas, and L. J. Gibson. Cellular materials as porous scaffolds for tissue engineering. Prog. Mater Sci. 46:273–282, 2001.Gong, S., H. Wang, Q. Sun, S. T. Xue, and J. Wang. Mechanical properties and in vitro biocompatibility of porous zein scaffolds. Biomaterials 27(20):3793–3799, 2006.Gutierrez, R. A., and E. T. Crumpler. Potential effect of geometry on wall shear stress distribution across scaffold surfaces. Ann. Biomed. Eng. 36(1):77–85, 2008.Hammer, D. A., and D. Lauffenburger. A dynamic-model for receptor-mediated cell adhesion to surfaces. Biophys. J. 52(3):475–487, 1987.Ho, S. T., and D. W. Hutmacher. A comparison of micro CT with other techniques used in the characterization of scaffolds. Biomaterials 27(8):1362–1376, 2006.Ho, M. H., P. Y. Kuo, H. J. Hsieh, T. Y. Hsien, L. T. Hou, J. Y. Lai, and D. M. Wang. Preparation of porous scaffolds by using freeze-extraction and freeze-gelation methods. Biomaterials 25(1):129–138, 2004.Hutmacher, D. W., J. T. Schantz, C. X. Lam, K. C. Tan, and T. C. Lim. State of the art and future directions of scaffold-based bone engineering from a biomaterials perspective. J. Tissue Eng. Regen. Med. 1(4):245–260, 2007.Izal, I., P. Aranda, P. Sanz-Ramos, P. Ripalda, G. Mora, F. Granero-Moltó, H. Deplaine, J. L. Gómez-Ribelles, G. G. Ferrer, V. Acosta, I. Ochoa, J. M. García-Aznar, E. J. Andreu, M. Monleón-Pradas, M. Doblaré, and F. Prósper. Culture of human bone marrow-derived mesenchymal stem cells on of poly(l-lactic acid) scaffolds: potential application for the tissue engineering of cartilage. Knee Surg. Sports Traumatol. Arthrosc., 2012.Kapur, S., D. J. Baylink, and K. H. Lau. Fluid flow shear stress stimulates human osteoblast proliferation and differentiation through multiple interacting and competing signal transduction pathways. Bone 32(3):241–251, 2003.Karande, T. S., J. L. Ong, and C. M. Agrawal. Diffusion in musculoskeletal tissue engineering scaffolds: design issues related to porosity, permeability, architecture, and nutrient mixing. Ann. Biomed. Eng. 32(12):1728–1743, 2004.Kelly, D. J., and P. J. Prendergast. Mechano-regulation of stem cell differentiation and tissue regeneration in osteochondral defects. J. Biomech. 38(7):1413–1422, 2005.Kreke, M. R., L. A. Sharp, Y. W. Lee, and A. S. Goldstein. Effect of intermittent shear stress on mechanotransductive signaling and osteoblastic differentiation of bone marrow stromal cells. Tissue Eng. Part A 14(4):529–537, 2008.Lacroix, D., A. Chateau, M. P. Ginebra, and J. A. Planell. Micro-finite element models of bone tissue-engineering scaffolds. Biomaterials 27(30):5326–5334, 2006.Lacroix, D., and P. J. Prendergast. A mechano-regulation model for tissue differentiation during fracture healing: analysis of gap size and loading. J. Biomech. 35(9):1163–1171, 2002.Li, S., J. R. De Wijn, J. Li, P. Layrolle, and K. De Groot. Macroporous biphasic calcium phosphate scaffold with high permeability/porosity ratio. Tissue Eng. 9:535–548, 2003.Melchels, F. P. W., B. Tonnarelli, A. L. Olivares, I. Martin, D. Lacroix, J. Feijen, et al. The influence of the scaffold design on the distribution of adhering cells after perfusion cell seeding. Biomaterials 32(11):2878–2884, 2011.O’Brien, F. J., B. A. Harley, M. A. Waller, I. Yannas, L. J. Gibson, and P. Prendergast. The effect of pore size on permeability and cell attachment in collagen scaffolds for tissue engineering. Technol. Health Care 15(1):3–17, 2007.Ochoa, I., J. A. Sanz, J. M. Garcia-Aznar, M. Doblare, D. M. Yunos, and A. R. Boccaccini. Permeability evaluation of 45S5 bioglass-based scaffolds for bone tissue engineering. J. Biomech. 42:257–260, 2009.Porter, B., R. Zauel, H. Stockman, R. Guldberg, and D. Fyhrie. 3-D computational modeling of media flow through scaffolds in a perfusion bioreactor. Mater. Res. 38:543–549, 2005.Sandino, C., S. Checa, P. J. Prendergast, and D. Lacroix. Simulation of angiogenesis and cell differentiation in a CaP scaffold subjected to compressive strains using a lattice modeling approach. Biomaterials 31(8):2446–2452, 2010.Sanz, J. A., J. M. García-Aznar, and M. Doblaré. On scaffold designing for bone regeneration: a computational multiscale approach. Acta Biomater. 5(1):219–229, 2009.Sanz, J. A., C. Kasper, M. van Griensven, J. M. Garcia-Aznar, I. Ochoa, and M. Doblare. Mechanical and flow characterization of Sponceram® carriers: evaluation by homogenization theory and experimental validation. J. Biomed. Mater. Res. B Appl. Biomater. 87B(1):42–48, 2008.Singh, H., S. H. Teoh, H. T. Low, and D. W. Hutmacher. Flow modelling within a scaffold under the influence of uni-axial and bi-axial bioreactor rotation. J. Biotechnol. 119:181–196, 2005.Sjollema, J., and H. J. Busscher. Deposition of polystyrene latex-particles toward polymethylmethacrylate in a parallel plate flow cell. J. Colloid Interface Sci. 132(2):382–394, 1989.Truscello, S., G. Kerckhofs, S. Van Bael, G. Pyka, J. Schrooten, and H. Van Oosterwyck. Prediction of permeability of regular scaffolds for skeletal tissue engineering: a combined computational and experimental study. Acta Biomater. 8(4):1648–1658, 2012.Woodfield, T. B., J. Malda, J. Wijn, F. Péters, J. Riesle, and C. A. van Blitterswijk. Design of porous scaffolds for cartilage tissue engineering using a three-dimensional fiber-deposition technique. Biomaterials 25(18):4149–4161, 2004

Implantation of Mouse Embryonic Stem Cell-Derived Cardiac Progenitor Cells Preserves Function of Infarcted Murine Hearts

Stem cell transplantation holds great promise for the treatment of myocardial infarction injury. We recently described the embryonic stem cell-derived cardiac progenitor cells (CPCs) capable of differentiating into cardiomyocytes, vascular endothelium, and smooth muscle. In this study, we hypothesized that transplanted CPCs will preserve function of the infarcted heart by participating in both muscle replacement and neovascularization. Differentiated CPCs formed functional electromechanical junctions with cardiomyocytes in vitro and conducted action potentials over cm-scale distances. When transplanted into infarcted mouse hearts, CPCs engrafted long-term in the infarct zone and surrounding myocardium without causing teratomas or arrhythmias. The grafted cells differentiated into cross-striated cardiomyocytes forming gap junctions with the host cells, while also contributing to neovascularization. Serial echocardiography and pressure-volume catheterization demonstrated attenuated ventricular dilatation and preserved left ventricular fractional shortening, systolic and diastolic function. Our results demonstrate that CPCs can engraft, differentiate, and preserve the functional output of the infarcted heart

A Combined Synthetic-Fibrin Scaffold Supports Growth and Cardiomyogenic Commitment of Human Placental Derived Stem Cells

Aims: A potential therapy for myocardial infarction is to deliver isolated stem cells to the infarcted site. A key issue with this therapy is to have at one\u27s disposal a suitable cell delivery system which, besides being able to support cell proliferation and differentiation, may also provide handling and elastic properties which do not affect cardiac contractile function. In this study an elastic scaffold, obtained combining a poly(ether)urethane-polydimethylsiloxane (PEtU-PDMS) semi-interpenetrating polymeric network (s-IPN) with fibrin, was used as a substrate for in vitro studies of human amniotic mesenchymal stromal cells (hAMSC) growth and differentiation. Methodology/Principal Findings: After hAMSC seeding on the fibrin side of the scaffold, cell metabolic activity and proliferation were evaluated by WST-1 and bromodeoxyuridine assays. Morphological changes and mRNAs expression for cardiac differentiation markers in the hAMSCs were examined using immunofluorescence and RT-PCR analysis. The beginning of cardiomyogenic commitment of hAMSCs grown on the scaffold was induced, for the first time in this cell population, by a nitric oxide (NO) treatment. Following NO treatment hAMSCs show morphological changes, an increase of the messenger cardiac differentiation markers [troponin I (TnI) and NK2 transcription factor related locus 5 (Nkx2.5)] and a modulation of the endothelial markers [vascular endothelial growth factor (VEGF) and kinase insert domain receptor (KDR)]. Conclusions/Significance: The results of this study suggest that the s-IPN PEtU-PDMS/fibrin combined scaffold allows a better proliferation and metabolic activity of hAMSCs cultured up to 14 days, compared to the ones grown on plastic dishes. In addition, the combined scaffold sustains the beginning of hAMSCs differentiation process towards a cardiomyogenic lineage