Two subforms of eukaryotic topoisomerase I Purification and structure-function relationships

AbstractA new method for isolation of eukaryotic topoisomerase 1 from calf thymus and from Jurkat-1 cells using HPLC has been developed. The method allows quantitative purification of high molecular weight topo I and of two low molecular weight fractions differing by their isoelectric points. It has been suggested that these fractions be characterized as two subforms of the enzyme possessing structural and functional differences. The differences in their specific activities, sensitivity to camptothecin and in their proteolytic digestion maps have been demonstrated for the two enzymes

Design, Performance, and Calibration of CMS Hadron Endcap Calorimeters

Detailed measurements have been made with the CMS hadron calorimeter endcaps (HE) in response to beams of muons, electrons, and pions. Readout of HE with custom electronics and hybrid photodiodes (HPDs) shows no change of performance compared to readout with commercial electronics and photomultipliers. When combined with lead-tungstenate crystals, an energy resolution of 8\% is achieved with 300 GeV/c pions. A laser calibration system is used to set the timing and monitor operation of the complete electronics chain. Data taken with radioactive sources in comparison with test beam pions provides an absolute initial calibration of HE to approximately 4\% to 5\%

Development of mathematical models and research strongly nonequilibrium developments taking into account space-time nonlocality

Based on the principles of locally-nonequilibrium thermodynamics were developed mathematical processes models of heat, mass, momentum, taking into account spatial and temporal nonlocality. The output of the differential equations is based on the account in the diffusion laws Fourier's, Fick's, Newton's, Hooke's, Ohm's, etc. accelerate in time as the specific fluxes (heat, mass, momentum) and the gradients of the corresponding variables. Study exact analytical solutions of the obtained models allowed us to discover new regularities of the changes of the desired parameters at low and ultra low values of temporal and spatial variables, and for all fast processes, time change which is comparable with the relaxation time. And, in particular, from the analysis of the exact analytical decision the fact of a time lag of acceptance of a boundary condition of the first kind demonstrating that in view of resistance of the body shown to warmth penetration process, its instantaneous warming up on boundary is impossible under no circumstances heat exchange with the environment is found. Therefore, the heat emission coefficient on a wall depends not only on heat exchange conditions (environment speed, viscosity and so forth), but also on physical properties of a body and it, in the first, is variable value in time and, in the second, it can not exceed some value, limit for each case

A method for solving problems of heat transfer during the flow of fluids in a plane channel

Using the integral method of heat-transfer with the additional boundary conditions we obtain the high precision approximate analytical solution of heat-transfer for a fluid, moving in plate-parallel channel with symmetric boundary conditions of the first kind. Because of the infinite speed of heat propagation described by a parabolic equation of heat-conduction, the temperature in the centre of channel would change immediately after the boundary conditions (of the first kind) application. We receive the approximate analytical solution of boundary value problem using the representation of this temperature in the form of additional required function and introducing the additional boundary conditions to satisfy the original differential equation in boundary points by the desired function. Using of the integral of heat balance we reduce the solving of differential equation in partial derivatives to integration of ordinary differential equation with respect to additional required function, that changes depending on longitudinal variable. We note that fulfillment of the original equation at the boundaries of the area with increasing number of approximations leads to the fulfillment of that equation inside the area. No need to integrate the differential equation on the transverse spatial variable, so we are limited only by the implementation of the integral of heat-transfer (averaged original differential equation), that allows to apply this method to boundary value problems, unsolvable using classic analytical methods

Heat transfer simulation in stirring boundary layer using the semiempirical turbulence theory

The dynamic and thermal boundary layer equations are derived for the stirring boundary layer using Prandtl semiempirical turbulence theory. Based on definition of the thermal perturbations front and supplementary boundary conditions the method of constructing an exact analytical solution of the boundary value problem simulating the formation of the thermal boundary layer in the dynamic boundary layer is obtained and applied to find the exact analytical solutions of thermal boundary layer differential equation almost with a given degree of accuracy. The velocity distribution in stirring dynamic boundary layer and its thickness were taken by the well — known relations, found from experiments. The supplementary conditions fulfillment is equivalent to the fulfillment of the initial differential equation in the boundary point and in the thermal perturbations front. So, the more supplementary conditions we use the better fulfillment of the initial differential equation in the thermal boundary layer we have, because the range of thermal perturbations front changing includes the whole range of transverse spatial variable changing. Analysis of calculations results allows to conclude that the layer thickness within a stirring dynamic boundary layer more than twice less than thermal layer thickness in a laminar dynamic boundary layer. The study of the received in this paper criteria-based equation shows that the difference of heat transfer coefficients in the range 20000⩽Re⩽30000 of the Reynolds number on the experimental not exceed 7%

On one method for solving transient heat conduction problems with asymmetric boundary conditions

Using additional boundary conditions and additional required function in integral method of heat-transfer we obtain approximate analytical solution of transient heat conduction problem for an infinite plate with asymmetric boundary conditions of the first kind. This solution has a simple form of trigonometric polynomial with coefficients exponentially stabilizing in time. With the increase in the count of terms of a polynomial the obtained solution is approaching the exact solution. The introduction of a time-dependent additional required function, setting in the one (point) of the boundary points, allows to reduce solving of differential equation in partial derivatives to integration of ordinary differential equation. The additional boundary conditions are found in the form that the required solution would implement the additional boundary conditions and that implementation would be equivalent to executing the original differential equation in boundary points. In this article it is noted that the execution of the original equation at the boundaries of the area only (via the implementation of the additional boundary conditions) leads to the execution of the original equation also inside that area. The absence of direct integration of the original equation on the spatial variable allows to apply this method to solving the nonlinear boundary value problems with variable initial conditions and variable physical properties of the environment, etc

Tests of CMS Hadron Forward Calorimeter Upgrade Readout Box Prototype

A readout box prototype for CMS Hadron Forward calorimeter upgrade is built and tested in CERN H2 beamline. The prototype is designed to enable simultaneous tests of different readout options for the four anode upgrade PMTs, new front-end electronics design and new cabling. The response of the PMTs with different readout options is uniform and the background response is minimal. Multi-channel readout options further enhance the background elimination. Passing all the electronics, mechanical and physics tests, the readout box proves to be capable of providing the forward hadron calorimeter operations requirements in the upgrade era