Connective tissue progenitor cell growth characteristics on textured substrates

Growth characteristics of human connective tissue progenitor (CTP) cells were investigated on smooth and textured substrates, which were produced using MEMS (microelectromechanical systems) fabrication technology. Human bone marrow derived cells were cultured for 9 days under conditions promoting osteoblastic differentiation on polydimethylsiloxane (PDMS) substrates comprising smooth (non-patterned) surfaces (SMOOTH), 4 different cylindrical post micro-textures (POSTS) that were 7–10 μm high and 5, 10, 20, and 40 μm diameter, respectively, and channel micro-textures (CHANNELS) with curved cross-sections that were 11 μm high, 45 μm wide, and separated by 5 μm wide ridges. Standard glass-tissue culture surfaces were used as controls. Micro-textures resulted in the modification of CTP morphology, attachment, migration, and proliferation characteristics. Specifically, cells on POSTS exhibited more contoured morphology with closely packed cytoskeletal actin microfilaments compared to the more random orientation in cells grown on SMOOTH. CTP colonies on 10 μm-diameter POSTS exhibited higher cell number than any other POSTS, and a significant increase in cell number (442%) compared to colonies on SMOOTH (71%). On CHANNELS, colonies tended to be denser (229%) than on POSTS (up to 140% on 10 μm POSTS), and significantly more so compared to those on SMOOTH (104%)

Релятивистское приближение для определения положений минимумов дифференциальных сечений и точек полной спиновой поляризации процесса упругого рассеяния электронов на тяжелых атомах

Пропонується метод оптичного потенціалу для описання процесу потенціального пружного розсіювання електронів багатоелектронними атомами з релятивістською поправкою до обмінної взаємодії. Ця поправка також використовується при самоузгоджених розрахунках атомних характеристик та величини дипольної статичної поляризовності атома-мішені. Підхід базується на наближенні локальної густини теорії функціонала густини та застосовується для розрахунку енергій та кутів особливостей у диференціальних перерізах і функціях спінової поляризації — відповідно критичних мінімумів та точок повної (100%) поляризації — при розсіюванні електронів на атомах ртуті в широкій, 10–1500 еВ, області енергій зіткнень.The optical potential approach has been suggested to describe the process of potential elastic electron scattering by a multielectron atom with the relativistic correction to the exchange interaction. This correction is also used for the self-consistent calculation of atomic characteristics and the target atom dipole static polarizability. The above approach is based on the local density approximation of the density functional theory. It is applied to calculate the energies and angles of the features in the differential cross sections and spin polarization functions, i.e. the critical minima and the points of total (100%) polarization of the electron scattering by Hg atoms in the wide (10–1500 eV) impact energy range

Post microtextures accelerate cell proliferation and osteogenesis

AbstractThe influence of surface microtexture on osteogenesis was investigated in vitro by examining the proliferation and differentiation characteristics of a class of adult stem cells and their progeny, collectively known as connective tissue progenitor cells (CTPs). Human bone marrow-derived CTPs were cultured for up to 60days on smooth polydimethylsiloxane (PDMS) surfaces and on PDMS with post microtextures that were 10μm in diameter and 6μm in height, with 10μm separation. DNA quantification revealed that the numbers of CTPs initially attached to both substrates were similar. However, cells on microtextured PDMS transitioned from lag phase after 4days of culture, in contrast to 6days for cells on smooth surfaces. By day 9 cells on the smooth surfaces exhibited arbitrary flattened shapes and migrated without any preferred orientation. In contrast, cells on the microtextured PDMS grew along the array of posts in an orthogonal manner. By days 30 and 60 cells grew and covered all surfaces with extracellular matrix. Western blot analysis revealed that the expression of integrin α5 was greater on the microtextured PDMS compared with smooth surfaces. Real time reverse transcription-polymerase chain reaction revealed that gene expression of alkaline phosphatase had decreased by days 30 and 60, compared with that on day 9, for both substrates. Gene expression of collagen I and osteocalcin was consistently greater on post microtextures relative to smooth surfaces at all time points

Can ‘eugenics’ be defended?

In recent years, bioethical discourse around the topic of ‘genetic enhancement’ has become increasingly politicized. We fear there is too much focus on the semantic question of whether we should call particular practices and emerging bio-technologies such as CRISPR ‘eugenics’, rather than the more important question of how we should view them from the perspective of ethics and policy. Here, we address the question of whether ‘eugenics’ can be defended and how proponents and critics of enhancement should engage with each other

Nicotinamide–2,2,2-trifluoro­ethanol (2/1)

The nicotinamide (NA) mol­ecules of the title compound, 2C6H6N2O·C2H3F3O, form centrosymmetric R 2 2(8) hydrogen-bonded dimers via N—H⋯O contacts. The asymmetric unit contains two mol­ecules of NA and one trifluoroethanol molecule disordered over two sites of equal occupancy. The packing consists of alternating layers of nicotinamide dimers and disordered 2,2,2-trifluoro­ethanol mol­ecules stacking in the c-axis direction. Intra­molecular C—H⋯O and inter­molecular N—H⋯N, O—H⋯N, C—H⋯N, C—H⋯O and C—H⋯F inter­actions are present

Midlatitude and high‐latitude electron density profiles in the ionosphere of Saturn obtained by Cassini radio occultation observations

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95024/1/jgra19781.pd

The Structure of Titan's Atmosphere from Cassini Radio Occultations

We present results from the two radio occultations of the Cassini spacecraft by Titan in 2006, which probed mid-southern latitudes. Three of the ingress and egress soundings occurred within a narrow latitude range, 31.34 deg S near the surface, and the fourth at 52.8 deg S. Temperature - altitude profiles for all four occultation soundings are presented, and compared with the results of the Voyager 1 radio occultation (Lindal et al., 1983), the HASI instrument on the Huygens descent probe (Fulchignoni et al., 2005), and Cassini CIRS results (Flasar et al., 2005; Achterberg et al., 2008b). Sources of error in the retrieved temperature - altitude profiles are also discussed, and a major contribution is from spacecraft velocity errors in the reconstructed ephemeris. These can be reduced by using CIRS data at 300 km to make along-track adjustments of the spacecraft timing. The occultation soundings indicate that the temperatures just above the surface at 31-34 deg S are about 93 K, while that at 53 deg S is about 1 K colder. At the tropopause, the temperatures at the lower latitudes are all about 70 K, while the 53 deg S profile is again 1 K colder. The temperature lapse rate in the lowest 2 km for the two ingress (dawn) profiles at 31 and 33 deg S lie along a dry adiabat except within approximately 200m of the surface, where a small stable inversion occurs. This could be explained by turbulent mixing with low viscosity near the surface. The egress profile near 34 deg S shows a more complex structure in the lowest 2 km, while the egress profile at 53 deg S is more stable

First results from the ionospheric radio occultations of Saturn by the Cassini spacecraft

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94835/1/jgra18257.pd