A piezo-bar pressure probe

Piezo-bar pressure type probe measures the impact velocity or pressure of a moving debris cloud. It measures pressures up to 200,000 psi and peak pressures may be recorded with a total pulse duration between 5 and 65 musec

Mesenchymal Stem Cell Spheroids Retain Osteogenic Phenotype Through α2β1 Signaling.

Unlabelled: The induction of mesenchymal stem cells (MSCs) toward the osteoblastic lineage using osteogenic supplements prior to implantation is one approach under examination to enhance their bone-forming potential. MSCs rapidly lose their induced phenotype upon removal of the soluble stimuli; however, their bone-forming potential can be sustained when provided with continued instruction via extracellular matrix (ECM) cues. In comparison with dissociated cells, MSC spheroids exhibit improved survival and secretion of trophic factors while maintaining their osteogenic potential. We hypothesized that entrapment of MSC spheroids formed from osteogenically induced cells would exhibit better preservation of their bone-forming potential than would dissociated cells from monolayer culture. Spheroids exhibited comparable osteogenic potential and increased proangiogenic potential with or without osteogenic preconditioning versus monolayer-cultured MSCs. Spheroids were then entrapped in collagen hydrogels, and the osteogenic stimulus was removed. In comparison with entrapped dissociated MSCs, spheroids exhibited significantly increased markers of osteogenic differentiation. The capacity of MSC spheroids to retain their osteogenic phenotype upon withdrawal of inductive cues was mediated by α2β1 integrin binding to cell-secreted ECM. These results demonstrate the capacity of spheroidal culture to sustain the mineral-producing phenotype of MSCs, thus enhancing their contribution toward bone formation and repair.SignificanceDespite the promise of mesenchymal stem cells (MSCs) for cell-based therapies for tissue repair and regeneration, there is little evidence that transplanted MSCs directly contribute to new bone formation, suggesting that induced cells rapidly lose their osteogenic phenotype or undergo apoptosis. In comparison with dissociated cells, MSC spheroids exhibit increased trophic factor secretion and improved cell survival. The loss of phenotype represents a significant clinical challenge for cell therapies, yet there is no evidence for whether MSC spheroids retain their osteogenic phenotype upon entrapment in a clinically relevant biomaterial. These findings demonstrate that MSC spheroids retain their osteogenic phenotype better than do dissociated MSCs, and this is due to integrin engagement with the cell-secreted extracellular matrix. These data provide evidence for a novel approach for potentiating the use of MSCs in bone repair

High-mobility solution-processed copper phthalocyanine-based organic field-effect transistors

© 2011 National Institute for Materials ScienceSolution-processed films of 1,4,8,11,15,18,22,25-octakis(hexyl) copper phthalocyanine (CuPc6) were utilized as an active semiconducting layer in the fabrication of organic field-effect transistors (OFETs) in the bottom-gate configurations using chemical vapour deposited silicon dioxide (SiO2) as gate dielectrics. The surface treatment of the gate dielectric with a self-assembled monolayer of octadecyltrichlorosilane (OTS) resulted in values of 4×10−2 cm2 V−1 s−1 and 106 for saturation mobility and on/off current ratio, respectively. This improvement was accompanied by a shift in the threshold voltage from 3V for untreated devices to −2V for OTS treated devices. The trap density at the interface between the gate dielectric and semiconductor decreased by about one order of magnitude after the surface treatment. The transistors with the OTS treated gate dielectrics were more stable over a 30-day period in air than untreated ones.Technology Strategy Board, UK (Project No: TP/6/EPH/6/S/K2536J)

An Experimental and Semi-Empirical Method to Determine the Pauli-Limiting Field in Quasi 2D Superconductors as applied to κ\kappa-(BEDT-TTF)2_2Cu(NCS)2_2: Strong Evidence of a FFLO State

We present upper critical field data for $\kappa$-(BEDT-TTF)$_2$Cu(NCS)$_2$ with the magnetic field close to parallel and parallel to the conducting layers. We show that we can eliminate the effect of vortex dynamics in these layered materials if the layers are oriented within 0.3 degrees of parallel to the applied magnetic field. Eliminating vortex effects leaves one remaining feature in the data that corresponds to the Pauli paramagnetic limit ($H_p$). We propose a semi-empirical method to calculate the $H_p$ in quasi 2D superconductors. This method takes into account the energy gap of each of the quasi 2D superconductors, which is calculated from specific heat data, and the influence of many body effects. The calculated Pauli paramagnetic limits are then compared to critical field data for the title compound and other organic conductors. Many of the examined quasi 2D superconductors, including the above organic superconductors and CeCoIn$_5$, exhibit upper critical fields that exceed their calculated $H_p$ suggesting unconventional superconductivity. We show that the high field low temperature state in $\kappa$-(BEDT-TTF)$_2$Cu(NCS)$_2$ is consistent with the Fulde Ferrell Larkin Ovchinnikov state.Comment: 8 pages, 9 figures, 10 years of dat

Magnetic field induced lattice anomaly inside the superconducting state of CeCoIn5_5: evidence of the proposed Fulde-Ferrell-Larkin-Ovchinnikov state

We report high magnetic field linear magnetostriction experiments on CeCoIn$_5$ single crystals. Two features are remarkable: (i) a sharp discontinuity in all the crystallographic axes associated with the upper superconducting critical field $B_{c2}$ that becomes less pronounced as the temperature increases; (ii) a distinctive second order-like feature observed only along the c-axis in the high field (10 T $\lesssim B \leq B_{c2}$) low temperature ($T \lesssim$ 0.35 K) region. This second order transition is observed only when the magnetic field lies within 20$^o$ of the ab-planes and there is no signature of it above $B_{c2}$, which raises questions regarding its interpretation as a field induced magnetically ordered phase. Good agreement with previous results suggests that this anomaly is related to the transition to the Fulde-Ferrel-Larkin-Ovchinnikov superconducting state.Comment: 3 figures, 5 page

Quantum Chessboards in the Deuterium Molecular Ion

We present a new algorithm for vibrational control in deuterium molecules that is feasible with current experimental technology. A pump mechanism is used to create a coherent superposition of the D2+ vibrations. A short, intense infrared control pulse is applied after a chosen delay time to create selective interferences. A `chessboard' pattern of states can be realized in which a set of even- or odd-numbered vibrational states can be selectively annihilated or enhanced. A technique is proposed for experimental realization and observation of this effect using 5 fs pulses of 790 nm radiation, with intermediate intensity (5e13 W/cm2)Comment: 12 pages, 5 figure

Measuring the halo mass of MgII absorbers from their cross-correlation with Luminous Red Galaxies

We study the cross-correlation between 716 MgII quasar absorption systems and about 100,000 Luminous Red Galaxies (LRGs) selected from the Sloan Digital Sky Survey Data Release 3 in the redshift range 0.4<z<0.8. The MgII systems were selected to have 2796 & 2803 rest-frame equivalent widths greater than 1.0 \AA and identifications confirmed by the FeII 2600 or MgI 2852 lines. Over co-moving scales 0.2--13/h Mpc, the MgII--LRG cross-correlation has an amplitude 0.69+/-0.09 times that of the LRG--LRG auto-correlation. Since LRGs have halo-masses of 10^{13} \msun, this strong cross-correlation implies that the absorber host-galaxies have halo-masses 1--2 times 10^{12} \msun.Comment: 3 pages, 2 figures, to appear in IAU 199 conf. proc.: "Probing Galaxies through Quasar Absorption Lines," eds. Williams, Shu, Menard; minor changes to match the edited versio

In vitro evidence for senescent multinucleated melanocytes as a source for tumor-initiating cells

Oncogenic signaling in melanocytes results in oncogene-induced senescence (OIS), a stable cell-cycle arrest frequently characterized by a bi- or multinuclear phenotype that is considered as a barrier to cancer progression. However, the long-sustained conviction that senescence is a truly irreversible process has recently been challenged. Still, it is not known whether cells driven into OIS can progress to cancer and thereby pose a potential threat. Here, we show that prolonged expression of the melanoma oncogene N-RAS61K in pigment cells overcomes OIS by triggering the emergence of tumor-initiating mononucleated stem-like cells from senescent cells. This progeny is dedifferentiated, highly proliferative, anoikis-resistant and induces fast growing, metastatic tumors. Our data describe that differentiated cells, which are driven into senescence by an oncogene, use this senescence state as trigger for tumor transformation, giving rise to highly aggressive tumor-initiating cells. These observations provide the first experimental in vitro evidence for the evasion of OIS on the cellular level and ensuing transformation