3,636 research outputs found

    Time-delayed models of gene regulatory networks

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    We discuss different mathematical models of gene regulatory networks as relevant to the onset and development of cancer. After discussion of alternativemodelling approaches, we use a paradigmatic two-gene network to focus on the role played by time delays in the dynamics of gene regulatory networks. We contrast the dynamics of the reduced model arising in the limit of fast mRNA dynamics with that of the full model. The review concludes with the discussion of some open problems

    Detection of human papillomavirus from liquid-based cytology specimens by in-house PCR: a pilot study

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    The Papanicolaou smear remains the most common method for the detection of precancerous changes in cervical cytology. However, the introduction of a liquidbased cytology (LBC) technique expands the possibility of cervical intraepithelial neoplasia (CIN) diagnosis, and permits detection of precancerous changes and human papillomavirus (HPV) simultaneously. In the pilot study reported here, using an in-house polymerase chain reaction (PCR) method, high-grade HPV was detected in 32% of a cohort of 38 patients. This conventional PCR method could be developed for use on a real-time PCR platform or in a microtitre-well format and subsequently automated

    Pressure sensor using liquid crystals

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    A pressure sensor includes a liquid crystal positioned between transparent, electrically conductive films (18 and 20), that are biased by a voltage (V) which induces an electric field (E) that causes the liquid crystal to assume a first state of orientation. Application of pressure (P) to a flexible, transparent film (24) causes the conductive film (20) to move closer to or farther from the conductive film (18), thereby causing a change in the electric field (E'(P)) which causes the liquid crystal to assume a second state of orientation. Polarized light (P.sub.1) is directed into the liquid crystal and transmitted or reflected to an analyzer (A or 30). Changes in the state of orientation of the liquid crystal induced by applied pressure (P) result in a different light intensity being detected at the analyzer (A or 30) as a function of the applied pressure (P). In particular embodiments, the liquid crystal is present as droplets (10) in a polymer matrix (12) or in cells (14) in a polymeric or dielectric grid (16) material in the form of a layer (13) between the electrically conductive films (18 and 20). The liquid crystal fills the open wells in the polymer matrix (12) or grid (16) only partially

    Critical Properties of Symmetric Nuclear Matter in Low-Density Regime Using Effective-Relativistic Mean Field Formalism

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    The effective field theory motivated relativistic mean-field (E-RMF) formalism is employed to study the equation of state (EoS) for the infinite symmetric nuclear matter at finite temperature using the recently developed forces FSUGarnet, IOPB-I, G3, and the well known NL3 force parameter. The EoS is then used to estimate the critical temperature TcT_c, pressure PcP_c and density ρc\rho_c of the symmetric nuclear matter for the liquid-gas phase transition. As TcT_c is not a constrained parameter in both experiments and theoretical calculations, there is a large uncertainty around its value. Although, the critical parameters are correlated among themselves. It is revealed that vector self-coupling ζ0\zeta_0 of used forces play determining role in EoS in finite temperature limit. Keeping the incompressibility in acceptable limit i.e. 240±\pm 20 MeV, the lower value of ζ0\zeta_0 gives a better result of TcT_c when compared to the several experimental data. The critical parameters however show weak correlation with the properties at saturation density at zero temperature. The compressibility factors calculated with these parameters are in agreement with the universal value of liquid-gas systems. Stability conditions are examined along with binodal and spinodal regions. Besides this, the thermodynamic properties like specific heat and latent heat are also worked out. We have carried out detailed consistency check of our calculations using critical exponents and standard scaling laws. All the exponents are well within the theoretical mean-field results

    Properties of hot finite nuclei and associated correlations with infinite nuclear matter

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    This work aim to study the various thermal characteristics of nuclei in view of the saturation and critical behavior of infinite nuclear matter. The free energy of a nucleus is parametrized using the density and temperature-dependent liquid-drop model and interaction among nucleons is worked out within the effective relativistic mean-field theory (E-RMF). The effective mass (m,^*) and critical temperature of infinite symmetric nuclear matter (TcT_c) of a given E-RMF parameter force play a seminal role in the estimation of thermal properties. A larger (m^*) and TcT_c of the E-RMF set estimate larger excitation energy, level density, and limiting temperature (Tl)(T_l) for a given nucleus. The limiting temperature of a nucleus also depends on the behavior of the nuclear gas surrounding the nucleus, making the equation of state (EoS) at subsaturation densities an important input. A stiff EoS in the subsaturation region estimates a higher pressure of the nuclear gas making it less stable. Since the TcT_c plays an important part in these calculations, we perform a Pearson correlation statistical study of fifteen E-RMF parameter sets, satisfying the relevant constraint on EoS. Effective mass seems to govern the thermal characteristics of infinite as well as finite nuclear matter in the framework of E-RMF theory.Comment: 13 pages, 9 figure

    Thermal effects in hot and dilute homogeneous asymmetric nuclear matter

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    We present a comprehensive analysis of hot and dilute isospin-asymmetric nuclear matter employing the temperature-dependent effective-relativistic mean-field theory (E-RMF). The E-RMF is applied to study the effect of δ\delta and ωρ\omega-\rho meson cross-coupling on the thermal properties of asymmetric nuclear matter using two recently developed IOPB-I and G3 parameter sets. These sets are known to reproduce the nuclear matter properties in agreement with various experimental and observational constraints. We consider the nuclear matter to be homogeneous and study the equation of state (EoS) for densities, temperature and asymmetry which are relevant for astrophysical simulations such as supernovae explosion. The effect of temperature is investigated in reference to the density-dependent free symmetry energy and its higher-order derivatives using the well known parabolic approximation. The larger value of λω\lambda_\omega cross-coupling in G3 in addition to the δ\delta meson coupling in G3 smoothen the free symmetry energy. Thermal effects on various state variables are examined at fixed temperature and isospin asymmetry by separating their T=0 and the finite-T expressions. The thermal effects are mainly governed by effective mass with larger effective mass estimating larger thermal contribution. The effect of temperature on isothermal and isentropic incompressibility is discussed which is in harmony with various available microscopic calculations. The liquid-gas phase transition properties are examined in asymmetric matter with two conserved charges in the context of different slope parameter and comparable symmetry energy in IOPB-I and G3 set. The spinodal instability, binodal curve and critical properties are found to be influenced by the slope parameter LsymL_{sym}

    Self -extinguishable cellulosic textile from Spinacia oleracea

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    Flame retardancy has been imparted to cellulosic cotton textiles using spinach (Spinacia Oleracea) juice (SJ). The extracted juice has been made alkaline and then applied a fresh to a bleached and premordanted cotton fabric. The flame retardant properties of both the control and the treated fabrics are analysed for limiting oxygen index (LOI) and vertical flammability. The study shows that the SJ treated fabrics have good flame retardant properties, with LOI of 30 for the SJ treated fabric, showing an increase by about 1.6 times compared to the control fabric with LOI of 18. As a result, the treated fabric does not catch flame and in the vertical flammability test, it burns with an afterglow and a propagation rate of 43.5 mm/min, which is almost 5 times lower than that observed with the control fabric. The mechanism of imparting the flame retardancy to the cotton fabric by application of SJ has been postulated and supported by SEM, EDX and char mechanism studies. The durability of the treatment to soap washing, rubbing, dry-cleaning and sunlight has also been studied. Besides, its application produces a natural green colour on the fabric, and no deterioration in other physical properties is observed
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