Identification of a set of genes showing regionally enriched expression in the mouse brain

Background

We have recorded responses from single neurons in murine visual cortex to determine the effectiveness of the input from the two murine cone photoreceptor mechanisms and whether there is any unique selectivity for cone inputs at this higher region of the visual system that would support the possibility of colour vision in mice. Each eye was stimulated by diffuse light, either 370 (strong stimulus for the ultra-violet (UV) cone opsin) or 505 nm (exclusively stimulating the middle wavelength sensitive (M) cone opsin), obtained from light emitting diodes (LEDs) in the presence of a strong adapting light that suppressed the responses of rods.

Results

Single cells responded to these diffuse stimuli in all areas of striate cortex. Two types of responsive cells were encountered. One type (135/323 – 42%) had little to no spontaneous activity and responded at either the on and/or the off phase of the light stimulus with a few impulses often of relatively large amplitude. A second type (166/323 – 51%) had spontaneous activity and responded tonically to light stimuli with impulses often of small amplitude. Most of the cells responded similarly to both spectral stimuli. A few (18/323 – 6%) responded strongly or exclusively to one or the other spectral stimulus and rarely in a spectrally opponent manner.

Conclusion

Most cells in murine striate cortex receive excitatory inputs from both UV- and M-cones. A small fraction shows either strong selectivity for one or the other cone mechanism and occasionally cone opponent responses. Cells that could underlie chromatic contrast detection are present but extremely rare in murine striate cortex.     

Numerical investigation of temperature effects in materials irradiated by high-energy heavy ions in the framework of heat conduction equation for electrons and lattice

A system of equations for electron gas and lattice around and along the trajectory of a heavy uranium ion with an energy of 700 MeV in nickel at constant heat capacity and heat conduction taken at room temperature is solved numerically in an axially symmetric cylindrical coordinate system. On the basis of the lattice temperature obtained as a function of radius around the ion trajectory and depth, a conclusion is made that the ionization energy losses of a uranium ion in nickel are sufficient for melting and evaporating the material from the surface. The maximum radius and depth of the region in which melting and evaporation take place are estimated.     

连续波锁模Pr3+:YLF激光器

本文报导了采用氩离子激光器来泵浦Pr³⁺:YLF晶体,应用声光调制器实现了主动锁模;同时应用振动─高反射平面镜也实现了被动锁模,两种锁模均得到了ps光脉冲.据作者了解这是这种晶体材料的第一次锁模运转.     

Reductive carbonylation of nitrobenzene over Pd/Fe/I2/Py and Pd/C/Fe/I2/Py catalytic systems

A simple catalytic system containing metallic palladium, iron and iodine has been shown to be very active in the carbonylation of nitrobenzene to carbamate. The influence of the components of the catalytic system studied on its selectivity and activity has been established. It has been found that the catalytic activity of palladium supported on carbon (using both lignite coal and bituminous coal) was not lower than the activity of metallic palladium. This revised version was published online in August 2006 with corrections to the Cover Date.     

Solution of sparse quasi-square rectangular systems by Gaussian elimination

We present a general method for the linear least-squares solutionof overdetermined and underdetermined systems. The method isparticularly efficient when the coefficient matrix is quasi-square,that is when the number of rows and number of columns is almostthe same. The numerical methods for linear least-squares problemsand minimum-norm solutions do not generally take account ofthis special characteristic. The proposed method is based onLU factorization of the original quasi-square matrix A, assumingthat A has full rank. In the overdetermined case, the LU factorsare used to compute a basis for the null space of A^T. The right-handside vector b is then projected onto this subspace and the least-squaressolution is obtained from the solution of this reduced problem.In the case of underdetermined systems, the desired solutionis again obtained through the solution of a reduced system.The use of this method may lead to important savings in computationaltime for both dense and sparse matrices. It is also shown inthe paper that, even in cases where the matrices are quite small,sparse solvers perform better than dense solvers. Some practicalexamples that illustrate the use of the method are included.     

Analysis of enhanced oil recovery formulations

Summary Methods for the determination of low levels of surfactants in produced oil field brines have been developed. Alkylbenzene sulfonates (ABS) and alkylether sulfates can be quantified at very low levels by high-performance liquid chromatography (HPLC) and mobile-phase ion chromatography (MPIC), respectively. These methods proved to be rapid, selective, and gave results in excellent agreement with traditional low-phase titration techniques. Although this paper records the use of these methods for analysis of oil field produced fluids, they should be easily adaptable to other situations wherein the analysis of these two classes of surfactants is required.     

Nanostructure and thermoelectric properties of ReSi 2+/-x thin films

Anomalies in the nanostructure evolution of ReSi(2+/-x) thin films have proved to be of large interest in connection with their thermoelectric properties. By means of electron microscopic methods the correlation between structural properties and transport behaviour has been studied. The short-range order of the amorphous state was characterised by reduced density functions calculated from diffuse electron diffraction diagram and is found to correlate with the temperature dependence of the electrical resistance. The crystallisation process observed in situ in the transmission electron microscope starts with the formation of relatively large ReSi(1.75) grains (up to 100 nm). In later stages, only smaller grains are growing. This leads to a decrease in the mean grain size and to the increase of the nanocrystalline volume fraction during the heat treatment. This behaviour allows the investigation of the thermopower as function of the nanocrystalline volume fraction. Thus, at a nanocrystalline content of about 35% the thermopower exhibits a maximum in accordance with calculations.     

Pseudo-steady-state solutions for solidification in a wedge

Polubarinova-Kochina's analytical differential equation methodis used to determine the pseudo-steady-state solution to problemsinvolving the freezing (solidification) of wedges of liquidwhich are initially at their fusion temperature. In particular,we consider four distinct problems for wedges which are: freezingwith the same constant boundary temperature, freezing with thesame constant boundary heat fluxes, freezing with distinct constantboundary temperatures and freezing with distinct constant fluxesat the boundaries. For the last two problems, a Heun's differentialequation with an unknown singularity is derived, which in bothcases admits a particularly elegant simple solution for thespecial case when the wedge angle is . The moving boundariesobtained are shown pictorially.