Alginate hydrogel has a negative impact on in vitro collagen 1 deposition by fibroblasts

Hydrogels have been widely investigated as 3D culture substrates because of their reported structural similarity to the extracellular matrix (ECM). Limited ECM deposition, however, occurs within these materials, so the resulting “tissues” bear little resemblance to those found in the body. Here matrix deposition by fibroblasts encapsulated within a calcium alginate (Ca-alg) hydrogel was investigated. Although the cells transcribed mRNA for coll Iα over a period of 3 weeks, very little collagen protein deposition was observed within the gel by histology or immunohistochemistry (IHC). Although molecular diffusion demonstrated charge dependency, this did not prevent the flux of both positively and negative charged amino acids through the gel, suggesting that the absence of ECM could not be attributed to substrate limitation. The flux of protein, however, was charge-dependent as proteins with a net negative charge passed quickly through the Ca-alg into the medium. The minimal collagen deposition within the Ca-alg was attributed to a combination of rapid movement of negatively charged procollagen through the gel and steric hindrance of fibril formation

Feasibility analysis of reciprocating magnetic heat pumps

The conceptual design selected for detailed system analysis and optimization is the reciprocating gadolinium core in a regenerative fluid column within the bore of a superconducting magnet. The thermodynamic properties of gadolinium are given. A computerized literature search for relevant papers was conducted and is being analyzed. Contact was made with suppliers of superconducting magnets and accessories, magnetic materials, and various types of hardware. A description of the model for the thermal analysis of the core and regenerator fluids is included

Second hyperpolarizability of carbon tetrachloride

Although present theories of nonlinear optics agree with observed behavior in simple atoms such as helium, more complex molecules containing many electrons, such as carbon tetrachloride (CCI4), cannot consistently be described by theory. Through experimental analysis of nonlinear materials, a new, more sophisticated model for describing their properties could be realized. The purpose of our experiment was to measure the nonlinear behavior of the second harmonic signal generated from CCI4 and to compare the results with the prediction by the CCSD(T) molecular model

The Origin of the Hot Gas in the Galactic Halo: Confronting Models with XMM-Newton Observations

We compare the predictions of three physical models for the origin of the hot halo gas with the observed halo X-ray emission, derived from 26 high-latitude XMM-Newton observations of the soft X-ray background between l=120\degr and l=240\degr. These observations were chosen from a much larger set of observations as they are expected to be the least contaminated by solar wind charge exchange emission. We characterize the halo emission in the XMM-Newton band with a single-temperature plasma model. We find that the observed halo temperature is fairly constant across the sky (~1.8e6-2.3e6 K), whereas the halo emission measure varies by an order of magnitude (~0.0005-0.006 cm^-6 pc). When we compare our observations with the model predictions, we find that most of the hot gas observed with XMM-Newton does not reside in isolated extraplanar supernova remnants -- this model predicts emission an order of magnitude too faint. A model of a supernova-driven interstellar medium, including the flow of hot gas from the disk into the halo in a galactic fountain, gives good agreement with the observed 0.4-2.0 keV surface brightness. This model overpredicts the halo X-ray temperature by a factor of ~2, but there are a several possible explanations for this discrepancy. We therefore conclude that a major (possibly dominant) contributor to the halo X-ray emission observed with XMM-Newton is a fountain of hot gas driven into the halo by disk supernovae. However, we cannot rule out the possibility that the extended hot halo of accreted material predicted by disk galaxy formation models also contributes to the emission.Comment: 20 pages, 14 figures. New version accepted for publication in ApJ. Changes include new section discussing systematic errors (Section 3.2), improved method for characterizing our model spectra (4.2.2), changes to discussion of other observations (5.1). Note that we can no longer rule out possibility that extended hot halo of accreted material contributes to observed halo emission (see 5.2.1

Dental Pulp Cell Behavior in Biomimetic Environments

There is emerging recognition of the importance of a physiologically relevant in vitro cell culture environment to promote maintenance of stem cells for tissue engineering and regenerative medicine purposes. In vivo, appropriate cellular cues are provided by local tissue extracellular matrix (ECM), and these are not currently recapitulated well in vitro using traditional cultureware. We therefore hypothesized that better replication of the in vivo environment for cell culture and differentiation could be achieved by culturing dental pulp cells with their associated ECM. Primary dental pulp cells were subsequently seeded onto pulp-derived ECM-coated cultureware. While at up to 24 h they exhibited the same level of adherence as those cells seeded on tissue culture–treated surfaces, by 4 d cell numbers and proliferation rates were significantly decreased in cells grown on pulp ECM compared with controls. Analysis of stem cell and differentiation marker transcripts, as well as Oct 3/4 protein distribution, supported the hypothesis that cells cultured on ECM better maintained a stem cell phenotype compared with those cultured on standard tissue culture–treated surfaces. Subsequent differentiation analysis of cells cultured on ECM demonstrated that they exhibited enhanced mineralization, as determined by alizarin red staining and mineralized marker expression. Supplementation of a 3% alginate hydrogel with pulp ECM components and dental pulp cells followed by differentiation induction in mineralization medium resulted in a time-dependent mineral deposition at the periphery of the construct, as demonstrated histologically and using micro–computed tomography analysis, which was reminiscent of tooth structure. In conclusion, data indicate that culture of pulp cells in the presence of ECM better replicates the in vivo environment, maintaining a stem cell phenotype suitable for downstream tissue engineering applications

Weed Hosts for Onion Thrips (Thysanoptera: Thripidae) and Their Potential Role in the Epidemiology of Iris Yellow Spot Virus in an Onion Ecosystem

Onion thrips, Thrips tabaci Lindeman, is a key foliage-feeding pest of onion worldwide and the principal vector of a serious onion pathogen, Iris yellow spot virus (IYSV). Long-term management of T. tabaci and IYSV will require an understanding of T. tabaci ecology and IYSV epidemiology in onion ecosystems. This study focused on identifying winter-annual, biennial and perennial weed species that host both T. tabaci and IYSV. Unlike summer-annual weeds, weeds with these habits survive overwinter and could serve as a green bridge for IYSV to survive between onion-growing seasons. T. tabaci larvae and adults were sampled every two weeks from 69 weed species in five areas located adjacent to onion fields in western New York in 2008 and 2009. Twenty-five of the 69 weed species were identified as hosts for T. tabaci larvae and populations were highest on the Brassicaceous weeds, Barbarea vulgaris Ait. f., Sinapis arvensis L., and Thalspi arvense L. None of these species are hosts for IYSV. Four of the 25 weed species were hosts for both T. tabaci larval populations and IYSV: common burdock, Arctium minus Bernh., dandelion, Taraxacum officinale G.H. Weber ex Wiggers, curly dock, Rumex crispus L., and chicory, Cichorium intybus L. Of these four weed species, T. officinale and A. minus may play an important role in the epidemiology of IYSV in New York onion fields because they may survive between onion-growing seasons, they are relatively abundant in the landscape, and they support relatively high densities of T. tabac

Three Interventions for Financial Therapy: Fostering an Examination of Financial Behaviors and Beliefs

Three interventions that address the emotional components of handling finances are proposed. Drawn from a stepwise model of financial therapy, the three interventions introduced here have the specific aim of incorporating the emotional attributes of traditional financial behaviors and beliefs. First, the Financial Genogram identifies family of origin issues that may affect financial behaviors; second, the Financial Landscape intervention is used when emotional stress occurs in collecting and examining financial documents; and third, the Financial Mirror broadens clients’ perspectives of their financial behaviors. Issues in future research and implementation of the Five Step model are addressed in treating financially distressed clients

Feasibility analysis of reciprocating magnetic heat pumps

A reciprocating gadolinium core in a regeneration fluid column in the warm bore of a superconducting solenoidal magnet is considered for magnetic refrigeration in 3.517 MW (1000 ton) applications. A procedure is presented to minimize the amount of superconducting cable needed in the magnet design. Estimated system capital costs for an ideal magnetic refrigerator of this type become comparable to conventional chillers as the frequency of reciprocation approaches 10 Hertz. A 1-D finite difference analysis of a regenerator cycling at 0.027 Hertz is presented which exhibits some of the features seen in the experiments of G. V. Brown

The cellular localization of avian influenza virus PB1-F2 protein alters the magnitude of IFN2 promoter and NFκB-dependent promoter antagonism in chicken cells.

The accessory protein, PB1-F2, of influenza A virus (IAV) functions in a chicken host to prolong infectious virus shedding and thus the transmission window. Here we show that this delay in virus clearance by PB1-F2 in chickens is accompanied by reduced transcript levels of type 1 interferon (IFN)-induced genes and NFκB-activated pro-inflammation cytokines. In vitro, two avian influenza isolate-derived PB1-F2 proteins, H9N2 UDL01 and H5N1 5092, exhibited the same antagonism of the IFN and pro-inflammation induction pathways seen in vivo, but to different extents. The two PB1-F2 proteins had different cellular localization in chicken cells, with H5N1 5092 being predominantly mitochondrial-associated and H9N2 UDL being cytoplasmic but not mitochondrial-localized. We hypothesized that PB1-F2 localization might influence the functionality of the protein during infection and that the protein sequence could alter cellular localization. We demonstrated that the sequence of the C-terminus of PB1-F2 determined cytoplasmic localization in chicken cells and this was linked with protein instability. Mitochondrial localization of PB1-F2 resulted in reduced antagonism of an NFκB-dependent promoter. In parallel, mitochondrial localization of PB1-F2 increased the potency of chicken IFN 2 induction antagonism. We suggest that mitochondrial localization of PB1-F2 restricts interaction with cytoplasmic-located IKKβ, reducing NFκB-responsive promoter antagonism, but enhances antagonism of the IFN2 promoter through interaction with the mitochondrial adaptor MAVS. Our study highlights the differential mechanisms by which IAV PB1-F2 protein can dampen the avian host innate signalling response

Fast switching of high current WBG power devices

Wide-band-gap power devices, such as Gallium Nitride High Electron Mobility Transistors and Silicon Carbide Field-effect Transistors, offer impressively fast switching performance compared to their traditional Silicon counterparts. However, Si designs have not stood still, and new generations of these devices offer good switching performance at competitive prices. This paper makes a comparative study between a representative selection of 650 V SiC MOSFET, GaN HEMT, and Si IGBT power switching devices. The devices are switched as fast as possible using a low inductance PCB design and no external gate resistors. A mathematical analysis of switching energy losses is presented, along with SPICE simulation and experimental test results for comparison