Unexpected crossover dynamics of single polymer in a corrugated tube

We present molecular dynamics study of a generic (coarse-grained) model for single-polymer diffusion confined in a corrugated cylinder. For a narrow tube, i.e., diameter of the cylinder $\delta < 2.3$, the axial diffusion coefficient $D_{||}$ scales as $D_{||} \propto N^{-3/2}$, with chain length $N$, up to $N \approx 100$ then crosses over to Rouse scaling for the larger $N$ values. The $N^{-3/2}$ scaling is due to the large fluctuation of the polymer chain along its fully stretched equilibrium conformation. The stronger scaling, namely $N^{-3/2}$, is not observed for an atomistically smooth tube and/or for a cylinder with larger diameter.Comment: 10 pages, 3 figures, LaTeX, version accepted by J. Chem. Phy

Modelling of Spark Ignition in Turbulent Reacting Droplet-laden Temporally Evolving Jet using LES

The turbulent jet flames in fuel sprays are of a great importance and are used in many practical applications, e.g., aircraft and automotive direct fuel injection systems. In this work we analyse the process of spark ignition in two-phase temporally evolving jet which carries the fuel spray. We focus on a dependence of the ignition on local flow structures, spark parameters and fuel droplets size. The fuel (n-Heptane) spray evaporates and mixes with the co-flowing oxidizer (air) creating a flammable mixture. The spark is modelled as a source term added to the energy equation. The goal of the research is to investigate the forced ignition and subsequent flame propagation/extinction in the low Mach number turbulent flow. The computations are carried out using Implicit Large Eddy Simulation (ILES) method by the high-order in-house LES solver. Liquid droplets are modelled in Lagrangian reference frame as point sources of mass, momentum and energy. The results show that combined effect of local fuel concentration, strain rate and scalar dissipation rate plays a main role in ignition. On the other hand, high rates of strain at the spark position cause substantial flame stretching leading to its extinction

Survey of Brain Variations of Young Adult and Aged B2 (-/-) Knockout Mice

Neuronal nicotinic acetylcholine receptors (nAChRs) are pentameric, ligand-gated ion channels whose activation is triggered by the neurotransmitter acetylcholine and by the exogenous compound, nicotine. In previous studies, disruptions in high affinity nAChR function have been shown to contribute to neuronal dysfunction as observed in Alzheimer’s disease (AD), Parkinson’s disease (PD), Lewy body dementia, autism, epilepsy, and schizophrenia. To study the effect of nAChRs, knockout mice, or mice genetically altered to lack certain subunits of their nAChRs, have been created. β2 (-/-) knockout mice lack the β2 subunit of their nicotinic acetylcholine receptors. These β2 (-/-) knockout mice have been shown to have a shorter lifespan, altered brain development and altered CNS function similar to changes seen in human ageing, making them a useful animal model for human dementia and neurodegeneration. It has been hypothesized that the β2 subunit has neuroprotective properties with respect to the neurons that express nicotinic acetylcholine receptors. The purpose of this study is to compare the volumes and cell densities of the olfactory bulb and the hippocampus in young adult (2-3 month old) and aged (18 month old) male β2 (-/-) knockout mice and age-matched wild type (+/+) mice. Both the olfactory bulb and hippocampus exhibit adult neurogenesis and the hippocampus is an important center for spatial learning and memory. We hypothesized that mice lacking the β2 subunit of their nAChRs, have excessive cell loss and therefore decreased brain area and that this effect would be pronounced in older β2 (-/-) knockout mice compared to younger mice. Currently, young adult mice (2-3 month old), have been evaluated, and no significant statistical difference in the olfactory bulb volume or hippocampus volume in β2(-/-) knockout mice compared to age-matched control mice has been observed. The olfactory bulb granular cell layer density of 2-3 month old mice also showed no significant difference compared to age-matched control mice. In aged mice (18 months old), hippocampus volumes and olfactory bulb volumes were measured and found to be the same as observed in the age-matched wild type group. In the future, cell densities of hippocampus in young adult mice and cell densities of olfactory bulb and hippocampus of aged mice, should be studied

Tension enhancement in branched macromolecules upon adhesion on a solid substrate

The effect of self-generated tension in the backbone of a bottle-brush (BB) macromolecule, adsorbed on an attractive surface, is studied by means of Molecular Dynamics simulations of a coarse-grained bead-spring model in the good solvent regime. The BB-molecule is modeled as a backbone chain of $L$ beads, connected by breakable bonds and with side chains, tethered pairwise to each monomer of the backbone. Our investigation is focused on several key questions that determine the bond scission mechanism and the ensuing degradation kinetics: how are frequency of bond scission and self-induced tension distributed along the BB-backbone at different grafting density $\sigma_g$ of the side chains? How does tension $f$ depend on the length of the side chains $N$, and on the strength of surface adhesion $\epsilon_s$? We examine the monomer density distribution profiles across the BB-backbone at different $\epsilon_s$ and relate it to adsorption-induced morphological changes of the macromolecule whereby side chains partially desorb while the remaining chains spread better on the surface. Our simulation data are found to be in qualitative agreement with experimental results and recent theoretical predictions. Yet we demonstrate that the interval of parameter values where these predictions hold is limited in $N$. Thus, at high values of $\epsilon_s$, too long side chains mutually block each other and freeze effectively the bottle-brush molecule.Comment: 6 pages, 8 figure

The Major Heat Shock Proteins, Hsp70 and Hsp90, in 2-Methoxyestradiol-Mediated Osteosarcoma Cell Death Model

2-Methoxyestradiol is one of the natural 17β-estradiol derivatives and a potential novel anticancer agent currently being under evaluation in advanced phases of clinical trials. However, the mechanism of anticancer action of 2-methoxyestradiol has not been yet fully established. In our previous studies we have demonstrated that 2-methoxyestradiol selectively induces the expression and nuclear translocation of neuronal nitric oxide synthase in osteosarcoma 143B cells. Heat shock proteins (Hsps) are factors involved in the regulation of expression and activity of nitric oxide synthases. Herein, we chose osteosarcoma cell lines differed in metastatic potential, metastatic 143B and highly metastatic MG63.2 cells, in order to further investigate the anticancer mechanism of 2-methoxyestradiol. The current study aimed to determine the role of major heat shock proteins, Hsp90 and Hsp70 in 2-methoxyestradiol-induced osteosarcoma cell death. We focused on the implication of Hsp90 and Hsp70 in control under expression of neuronal nitric oxide synthase, localization of the enzyme, and further generation of nitro-oxidative stress. To give the insight into the role of Hsp90 in regulation of anticancer efficacy of 2-methoxyestradiol, we used geldanamycin as a potent Hsp90 inhibitor. Herein, we evidenced that inhibition of Hsp90 controls the protein expression of 2-methoxyestradiol-induced neuronal nitric oxide synthase and inhibits enzyme nuclear translocation. We propose that decreased level of neuronal nitric oxide synthase protein after a combined treatment with 2-methoxyestradiol and geldanamycin is directly associated with the accompanying upregulation of Hsp70 and downregulation of Hsp90. This interaction resulted in abrogation of anticancer efficacy of 2-methoxyestradiol by geldanamycin

The laboratory telerobotic manipulator program

New opportunities for the application of telerobotic systems to enhance human intelligence and dexterity in the hazardous environment of space are presented by the NASA Space Station Program. Because of the need for significant increases in extravehicular activity and the potential increase in hazards associated with space programs, emphasis is being heightened on telerobotic systems research and development. The Laboratory Telerobotic Manipulator (LTM) program is performed to develop and demonstrate ground-based telerobotic manipulator system hardware for research and demonstrations aimed at future NASA applications. The LTM incorporates traction drives, modularity, redundant kinematics, and state-of-the-art hierarchical control techniques to form a basis for merging the diverse technological domains of robust, high-dexterity teleoperations and autonomous robotic operation into common hardware to further NASA's research

Identification of differentially expressed genes in cutaneous squamous cell carcinoma by microarray expression profiling

BACKGROUND: Carcinogenesis is a multi-step process indicated by several genes up- or down-regulated during tumor progression. This study examined and identified differentially expressed genes in cutaneous squamous cell carcinoma (SCC). RESULTS: Three different biopsies of 5 immunosuppressed organ-transplanted recipients each normal skin (all were pooled), actinic keratosis (AK) (two were pooled), and invasive SCC and additionally 5 normal skin tissues from immunocompetent patients were analyzed. Thus, total RNA of 15 specimens were used for hybridization with Affymetrix HG-U133A microarray technology containing 22,283 genes. Data analyses were performed by prediction analysis of microarrays using nearest shrunken centroids with the threshold 3.5 and ANOVA analysis was independently performed in order to identify differentially expressed genes (p < 0.05). Verification of 13 up- or down-regulated genes was performed by quantitative real-time reverse transcription (RT)-PCR and genes were additionally confirmed by sequencing. Broad coherent patterns in normal skin vs. AK and SCC were observed for 118 genes. CONCLUSION: The majority of identified differentially expressed genes in cutaneous SCC were previously not described

Influence of Grapeseed oIl MIcroeMulsIon addItIons on textural and sensory propertIes of a Wheat-rye Bread and a Wheat french loaf

abstract Boudova Pecivova, P., J. Mlcek, v. kuBan and J. Bartek, 2014. Influence of grapeseed oil micro emulsion additions on textural and sensory properties of a wheatrye bread and a wheat French loaf. Bulg. J. Agric. Sci., 20: 510514 Additions of o/w microemulsions made from Vitis vinifera virgin grape seed oil on textural and sensory properties of wheatrye bread and wheat French loaf were evaluated. Texture analysis of the final products showed no differences in firm ness. The samples of wheat French loaf with additions of the microemulsion had lower dryness in comparison to control wheat French loaf. The samples of wheat French loaf with higher additions of the microemulsion (3040 g/kg) had better quality than the control sample of the wheat French loaf. Selected assessors evaluated the samples of French loaf with additions of the mi croemulsion as better quality and less dry

DINOSAUR FOOTPRINTS FROM THE GLEN ROSE FORMATION (PALUXY RIVER, DINOSAUR VALLEY STATE PARK, SOMERVELL COUNTY, TEXAS)

Dinosaur footprints are found in the Glen Rose Formation and other Lower Cretaceous stratigraphic units over much of central Texas (Pittman, 1989; Rogers, 2002; Farlow et al., 2006). Dinosaur tracks were discovered in the rocky bed of the Paluxy River, near the town of Glen Rose, Texas, early in the 20th Century (Jasinski, 2008; Farlow et al., 2012b). Ellis W. Shuler of Southern Methodist University did pioneering studies on the dinosaur tracks (Shuler 1917, 1935, 1937), and Langston (1974) summarized much of the early literature. What really put the dinosaur footprints of the Paluxy River on the map, though, were the herculean efforts that Roland T. Bird of the American Museum of Natural History made to secure trackway slabs for display at that institution and at the Texas Memorial Museum in Austin (Bird, 1985; Jasinski, 2008). In 1970 Dinosaur Valley State Park was created to protect the dinosaur footprints. This guidebook briefly summarizes earlier work, and also serves as an interim report of research of our group still in progress, concerned with identifying the makers of the Paluxy River footprints, and determining what those animals were up to as they made their tracks. We will offer some comparisons of the dinosaur tracks of the Glen Rose Formation with those from other ichnofaunas around the world. The last quarter-century has seen an explosive increase in the technical literature dealing with dinosaur footprints, and we cannot possibly cite all of the relevant studies. For the sake of brevity we will emphasize publications from the present century, and summary papers and books, as much as possible. Even with this restriction, however, the literature is so vast that the literature-cited “tail” of this report starts to wag the “dog” of the text