Two novel regions of interstitial deletion on chromosome 8p in colorectal cancer

We have investigated interstitial deletions of chromosome 8 in 70 colorectal carcinomas and 11 colonic adenomas using 11 microsatellite markers, including eight spanning the centromeric region of chromosome 8p (p11.2-p12). Allelic loss or imbalance was observed in 38 (54%) cancers and four (36%) adenomas. Twenty-eight (40%) of the cancers had deletions of 8p11.2-p12. Two distinct and independent regions of interstitial loss were found within this region. Fluorescent in situ hybridization, using an alpha satellite repeat probe to the centromere of 8p and two probes to the P1 region, was performed in four tumours that demonstrated allelic imbalance. Localized heterozygous deletions were confirmed in all four tumours. Eleven (16%) cancers had localized deletion in the region ANK-1 to D8S255 (P1) and a further eleven (16%) cancers had a less well localized deletion in the region defined by the markers D8S87 to D8S259 (P2). Loss of both centromeric loci was identified in a further six (9%) tumours. A functional significance for these two deletion regions was sought by correlation with primary and secondary tumour characteristics. Isolated P2 deletion was associated with 'early' T1 cancers (2p=0.0002), and were also identified in 3/11 adenomas. Conversely, interstitial deletions of the P1 locus were more frequently seen in 'locally invasive' T3/4 cancers (2p=0.015), and isolated P1 deletions were also associated with the presence of liver metastases (2p=0.016). Our data provide evidence of at least two genes within the 8p11.2-p12 region, mutations in which may confer different and independent roles in the pathogenesis of colorectal cancer.     

Factors Influencing Biodegradable Dissolved Organic Carbon Measurement

The inocula requirements and other experimental conditions for the biodegradable dissolved organic carbon (BDOC) procedure have been investigated and optimized to facilitate its use as a routine parameter for characterizing treatment plant performance. Initial inocula of unfiltered secondary effluent, commercial biochemical oxygen demand seed, mixed-liquor suspended solids (MLSS), and incubation temperatures of 20 and 37°C were examined using standard solutions of known DOC, treatment plant effluents, and ozonated treatment plant effluents. Among all inocula tested, MLSS provides the fastest BDOC exertion rate. It is possible to measure BDOC within five days using a larger volume of MLSS inoculum. The results from this research may be used to support the development of a standard BDOC method for water quality assessment.     

The corrosion behavior of TiN coated and uncoated incoloy 800 alloy

Incoloy alloy 800 is used in a variety of applications in industry as well as in domestic appliances for sheeting on electric heating elements. The composition of the alloy enables it to resist deterioration in many corrosive environments. However, resistance of the alloy to corrosion in aqueous media needs to be further examined. The present study examines the corrosion properties of Incoloy 800 alloy of both coated and uncoated workpieces obtained in a 0.1N H₂SO₄ + 0.05N NaCl solution. TiN coating is achieved using a physical vapor deposition (PVD) technique while corrosion tests are carried out using electrochemical polarization methods. Moreover, in order to examine the influence of hydrogen diffusion, reduction of hydrogen at the Incoloy 800 surface is carried out in a solution of 0.1N HNO₃ + 1 g/L thiourea. Tensile tests are conducted on the workpieces to determine the influence of hydrogen embrittlement on the resulting mechanical properties of the substrate. To examine the pit formation and stress induced microcracking, scanning electron microscope (SEM) analysis is carried out. The results show that the corrosion resistance of the alloy improves after TiN coating. In addition, no specific pattern or differentiation on the pit geometry is observed. The pitting rate and its size reduce considerably for TiN coated workpieces.     

New design of full band differentiators based on Taylor series

The classical central difference approximations of the derivative of a function based on Taylor series are the same as type III maximally linear digital differentiators for low frequencies. A new finite difference formula is derived which can be implemented as a full band type IV maximally linear differentiator. The differentiator is compared with type III maximally linear and type IV equiripple minimax differentiators. A modification is proposed in the design to minimise the region of inaccuracy near the Nyquist frequency edge     

Mode-coupling analysis of multipole symmetric resonant add/dropfilters

Time-dependent mode-coupling theory is used to analyze a type of resonant add/drop filter based on the excitation of degenerate symmetric and antisymmetric modes. Flat-top transfer functions are achieved with higher order filters that utilize multiple resonator pairs, designed to satisfy the degeneracy conditions. The resulting analytic expressions lead to an equivalent circuit and the transfer characteristics of the filter are related to standard L-C circuit designs     

Effect of rare-earth (Eu, Yb and Ag) substitutions on superconducting properties of the Bi1.7Pb0.3 Sr2Ca2−xRx(R = Eu, Yb, and Ag)Cu3OY system

The superconducting properties of Bi^1.7Pb_0.3Sr₂Ca^2–xR^x(R = Eu, Yb and Ag)Cu₃O_Y have been investigated by X-ray diffraction, electrical resistance and the peritectic transition of these superconductors was studied kinetically under different atmospheres and temperature gradients. X-ray diffraction results show that the volume fraction of the high-T_c (2 2 2 3) phase decreases and that of the low-T_c (2 2 1 2) phase increases as Eu, Yb and Ag concentrations increase. The resistivity measurements reveal that the T_c onset decreases down to 100 K for Eu, 85 K for Yb and 106 K for Ag concentrations. These results are explained on the basis of possible variations of hole concentration with trivalent rare earth ion substitutions. Activation energies and frequency factors for crystallisation were determined by non-isothermal differential thermal analysis (DTA), employing different models. It was found that both peritectic transition and reaction rate were dependent on the ambient atmosphere. Kinetic studies under different atmospheres revealed that the thermal stability of Bi-2 2 1 2 phase was greatly enhanced under oxygen atmosphere.     

A computational study of unsteady radiative magnetohydrodynamic Blasius and Sakiadis flow with leading‐edge accretion (ablation)

The present study investigates the influence of the magnetic field, thermal radiation, Prandtl number, and leading‐edge accretion/ablation on Blasius and Sakiadis flow. The convective boundary condition is employed to investigate the heat transfer. The nondimensional governing boundary layer equations have been solved by the homotopy analysis method for different values of the pertinent parameters. The effects of these parameters on the dimensionless velocity, temperature, skin friction, and Nusselt number are also investigated for various values of relevant parameters affecting the flow and heat transfer phenomena. The most relevant outcomes of the present study are that enhancement in magnetic field strength undermines the flow velocity establishing thinner velocity boundary layer for both Blasius and Sakiadis flows while an increase in accretion/ablation effect at leading‐edge manifests in a deceleration in velocity for Blasius case and the opposite trend is observed for Sakiadis flow. Another important outcome is that an increase in radiation and accretion/ablation at leading‐edge upsurges the fluid temperature leading to enhancement in the thermal boundary layer. For both Blasius and Sakiadis flow, the skin friction coefficient and the heat transfer rate decline with the enhancement of the leading‐edge accretion parameter. The results are compared with the existing data and are found in good agreement.     

Numerical studies on heat and fluid flow of nanofluid in a partially heated vertical annulus

A numerical investigation on natural convective heat transfer of nanofluid (Al₂O₃+water) inside a partially heated vertical annulus of high aspect ratio (352) has been carried out. The computational fluid dynamics solver Ansys Fluent is used for simulation and results are presented for various volume fraction of nanoparticles (0‐0.04) at different heat flux values (3‐12 kW/m²). Two well‐known correlations for evaluating thermal conductivity and viscosity have been used. Thus different combinations of the available correlations have been set to form four models (I, II, III, and IV). Therefore, a detailed analysis has been executed to identify effects of thermophysical properties on heat transfer and fluid flow of nanofluids using different models. The results show enhancement in heat transfer coefficient with volume fraction of nanoparticles. Highest enhancement achieved is found to be 14.17% based on model III, while the minimum is around 7.27% based on model II. Dispersion of nanoparticles in base fluid declines the Nusselt number and Reynolds number with different rates depending on various models. A generalized correlation is proposed for Nusselt number of nanofluids in the annulus in terms of volume fraction of nanoparticles, Rayleigh number, Reynolds number, and Prandtl number.     

A revised viscoelastic micropolar nanofluid model with motile micro‐organisms and variable thermal conductivity

In the present study, a magnetized micropolar nanofluid and motile micro‐organism with variable thermal conductivity over a moving surface have been discussed. The mathematical modeling has been formulated using a second‐grade fluid model and a revised form of the micropolar fluid model. The governing fluid contains micro‐organisms and nanoparticles. The resulting nonlinear mathematical differential equations have been solved with the help of the homotopy analysis method. The graphical and physical features of buoyancy force, micro‐organisms, magnetic field, microrotation, and variable thermal conductivity have been discussed in detail. The numerical results for Nusselt number, motile density number, and Sherwood number are presented with the help of tables. According to the graphical effects, it is noted that the buoyancy ratio and the bioconvection parameter resist the fluid motion. An enhancement in the temperature profile is observed due to the increment in thermal conductivity. Peclet number tends to diminish the motile density profile; however, the viscoelastic parameter magnifies the motile density profile.     

Melting heat transfer analysis of electrically conducting nanofluid flow over an exponentially shrinking/stretching porous sheet with radiative heat flux under a magnetic field

Modern magnetic nanomaterial processing operations are progressing rapidly and require increasingly sophisticated mathematical models for their optimization. Stimulated by such developments, in this paper, a theoretical and computational study of a steady magnetohydrodynamic nanofluid over an exponentially stretching/shrinking permeable sheet with melting (phase change) and radiative heat transfer is presented. Besides, wall transpiration, that is, suction and blowing (injection), is included. This study deploys Buongiorno's nanofluid model, which simulates the effects of the Brownian motion and thermophoresis. The transport equations and boundary conditions are normalized via similarity transformations and appropriate variables, and the similarity solutions are shown to depend on the transpiration parameter. The emerging dimensionless nonlinear coupled ordinary differential boundary value problem is solved numerically with the Newton-Fehlberg iteration technique. Validation with special cases from the literature is included. The increase in the magnetic field, that is, the Hartmann number, is observed to elevate nanoparticle concentration and temperature, whereas it dampens the velocity. Higher values of the melting parameter consistently decelerate the boundary layer flow and suppress temperature and nanoparticle concentration. A higher radiative parameter strongly increases temperature (and thermal boundary layer thickness) and weakly accelerates the flow. The increase in the Brownian motion reduces nanoparticle concentrations, whereas a greater thermophoretic body force strongly enhances them. The Nusselt number and Sherwood number are observed to be decreased with an increasing Hartmann number, whereas they are elevated with a stronger wall suction and melting parameter.