Silver-assisted laser desorption ionization for high spatial resolution imaging mass spectrometry of olefins from thin tissue sections.

Silver has been demonstrated to be a powerful cationization agent in mass spectrometry (MS) for various olefinic species such as cholesterol and fatty acids. This work explores the utility of metallic silver sputtering on tissue sections for high resolution imaging mass spectrometry (IMS) of olefins by laser desorption ionization (LDI). For this purpose, sputtered silver coating thickness was optimized on an assorted selection of mouse and rat tissues including brain, kidney, liver, and testis. For mouse brain tissue section, the thickness was adjusted to 23 ± 2 nm of silver to prevent ion suppression effects associated with a higher cholesterol and lipid content. On all other tissues, a thickness of at 16 ± 2 nm provided the best desorption/ionization efficiency. Characterization of the species by MS/MS showed a wide variety of olefinic compounds allowing the IMS of different lipid classes including cholesterol, arachidonic acid, docosahexaenoic acid, and triacylglyceride 52:3. A range of spatial resolutions for IMS were investigated from 150 μm down to the high resolution cellular range at 5 μm. The applicability of direct on-tissue silver sputtering to LDI-IMS of cholesterol and other olefinic compounds presents a novel approach to improve the amount of information that can be obtained from tissue sections. This IMS strategy is thus of interest for providing new biological insights on the role of cholesterol and other olefins in physiological pathways or disease.

Modeling water movement in horizontal columns using fractal theory

Fractal mathematics has been used to characterize water and solute transport in porous media and also to characterize and simulate porous media properties. The objective of this study was to evaluate the correlation between the soil infiltration parameters sorptivity (S) and time exponent (n) and the parameters dimension (D) and the Hurst exponent (H). For this purpose, ten horizontal columns with pure (either clay or loam) and heterogeneous porous media (clay and loam distributed in layers in the column) were simulated following the distribution of a deterministic Cantor Bar with fractal dimension H" 0.63. Horizontal water infiltration experiments were then simulated using Hydrus 2D software. The sorptivity (S) and time exponent (n) parameters of the Philip equation were estimated for each simulation, using the nonlinear regression procedure of the statistical software package SAS®. Sorptivity increased in the columns with the loam content, which was attributed to the relation of S with the capillary radius. The time exponent estimated by nonlinear regression was found to be less than the traditional value of 0.5. The fractal dimension estimated from the Hurst exponent was 17.5 % lower than the fractal dimension of the Cantor Bar used to generate the columns.

Temporary Traffic Control and Enforcement of Traffic Laws in Closed Road Sections, June 2007

Public travel by motor vehicles is often necessary in road and street sections that have been officially closed for construction, repair, and/or other reasons. This authorization is permitted in order to provide access to homes and businesses located beyond the point of closure. The MUTCD does address appropriate use of specific regulatory signs at the entrance to closed sections; however, direct guidance for temporary traffic control measures within these areas is not included but may be needed. Interpretation and enforcement of common practices may vary among transportation agencies. For example, some law enforcement officers in Iowa have indicated a concern regarding enforcement and jurisdiction of traffic laws in these areas because the Code of Iowa only appears to address violations on roadways open to “public travel.” Enforcement of traffic laws in closed road sections is desirable to maintain safety for workers and for specifically authorized road users. In addition, occasional unauthorized entry by motor vehicles is experienced in closed road areas causing property damage. Citations beyond simple trespass may be advisable to provide better security for construction sites, reduce economic losses from damage to completed work, and create safer work zones.

Distorted-wave calculation of cross sections for inner-shell ionization by electron and positron impact

The relativistic distorted-wave Born approximation is used to calculate differential and total cross sections for inner shell ionization of neutral atoms by electron and positron impact. The target atom is described within the independent-electron approximation using the self-consistent Dirac-Fock-Slater potential. The distorting potential for the projectile is also set equal to the Dirac-Fock-Slater potential. For electrons, this guarantees orthogonality of all the orbitals involved and simplifies the calculation of exchange T-matrix elements. The interaction between the projectile and the target electrons is assumed to reduce to the instantaneous Coulomb interaction. The adopted numerical algorithm allows the calculation of differential and total cross sections for projectiles with kinetic energies ranging from the ionization threshold up to about ten times this value. Algorithm accuracy and stability are demonstrated by comparing differential cross sections calculated by our code with the distorting potential set to zero with equivalent results generated by a more robust code that uses the conventional plane-wave Born approximation. Sample calculation results are presented for ionization of K- and L-shells of various elements and compared with the available experimental data.

Spatial correlations and cross sections of clusters in the A + B -> 0 reaction

We consider the distribution of cross sections of clusters and the density-density correlation functions for the A+B¿0 reaction. We solve the reaction-diffusion equations numerically for random initial distributions of reactants. When both reactant species have the same diffusion coefficients the distribution of cross sections and the correlation functions scale with the diffusion length and obey superuniversal laws (independent of dimension). For different diffusion coefficients the correlation functions still scale, but the scaling functions depend on the dimension and on the diffusion coefficients. Furthermore, we display explicitly the peculiarities of the cluster-size distribution in one dimension.

Classical cross sections for relativistic spinning particles

We propose a definition of classical differential cross sections for particles with essentially nonplanar orbits, such as spinning ones. We give also a method for its computation. The calculations are carried out explicitly for electromagnetic, gravitational, and short-range scalar interactions up to the linear terms in the slow-motion approximation. The contribution of the spin-spin terms is found to be at best 10-6 times the post-Newtonian ones for the gravitational interaction.

Sceaux détachés (originaux en cire), cachets, armoiries, jetons et médailles, dessinés ou gravés. XI 356 numéros (ex-libris armoriés, sceaux dessinés ou gravés, cachets, armoiries, dessins de jetons et médailles, etc.).

Contient : N° 53 Sceau de Catherine d'Alençon, duchesse de Bavière (1416) ; Nos 56 et 57 Sceaux de Jean, duc de Calabre et de Lorraine (31 octobre 1465) et de son fils aîné ; N° 58 Sceau de Marguerite, reine d'Angleterre (1470) ; N° 59 Sceau de Bernardin Bochetel, évêque de Rennes (1564) ; N° 61 « S. Petri, Dei gratia archiepiscopi Tholosani » [Pierre V de Lion ?] ; Nos 62 et 64 Sceau de Robert d'Alençon, comte du Perche (1370 et 1375) ; Nos 72 et 81 Médailles du roi René (dessins) ; N° 73 Sceau de Jeanne, reine de Jérusalem, Sicile et Aragon (1498), avec contre-sceau ; N° 74 Sceau et contre-sceau de Louis de France, duc d'Anjou et roi de Sicile ; N° 75 Sceau d'Isabelle, comtesse du Maine et de Guise (1462), avec contresceau ; N° 76 Sceau et contre-sceau de René d'Anjou, roi de Sicile et de Jérusalem ; N° 77 « [S. Nicolai] ducis Calabrie, Lotharingie, A[ndegavie]..., » avec contre-sceau ; N° 78 Sceau de Pierre, comte d'Alençon, seigneur de Fougères, vicomte de Beaumont (1378), avec contre-sceau ; Nos 79 et 82 Sceau et contre-sceau de Louis II, roi de Jérusalem et de Sicile et comte d'Anjou (1407 et 1408) ; Nos 80 et 88 Sceau et contre-sceau de Robert, comte d'Artois ; N° 84 « S. novum Ludovici, regis Fran. filii, ducis Andegavensis et comitis Cenomannensis, » avec contre-sceau (1374) ; N° 85 Sceau et contre-sceau de Catherine, fille aînée du duc d'Alençon, « comtesse de Montfort, dame de Sonois » ; N° 86 Sceau et contre-sceau de Charles, comte du Maine (1451) ; N° 87 « Scel René d'Anjou, chlr., baron et s. de Mézières et de Thury, » avec contre-sceau ; N° 89 Sceau de Yolande reine de Jérusalem et de Sicile (1428) ; N° 94 Sceau d'Henri de Carinthie, évêque de Troyes ; cf. vol. 3101, n° 8 ; N° 101 Sceau de Charles, comte d'Alençon (1361) ; N° 112 Sceau d'Antoine de Cravant, abbé de la Trinité de Vendôme ; cf. vol. 3113, n° 7 ; N° 113 « Sigillum Johannis, episcopi Silvanectensis » [Jean Neveu † 1499, ou Jean Calveau † 1522] ; N° 115 Sceau de Jean de Tinteniac du Percher, abbé de Saint-Aubin († 1525) ; N° 120 « Scel Pierre, bastart d'Alençon » (1419) ; N° 128 « Constras. Ludovici, regis condam Francor. filii, ducis Andegavie et comit. Cenamanie. » ; N° 154 Sceau de Mathieu, évêque de Troyes (1169-1180) ; N° 257 Sceau de René, duc d'Alençon (1478)

Spatial correlations and cross sections of clusters in the A + B -> 0 reaction

We consider the distribution of cross sections of clusters and the density-density correlation functions for the A+B¿0 reaction. We solve the reaction-diffusion equations numerically for random initial distributions of reactants. When both reactant species have the same diffusion coefficients the distribution of cross sections and the correlation functions scale with the diffusion length and obey superuniversal laws (independent of dimension). For different diffusion coefficients the correlation functions still scale, but the scaling functions depend on the dimension and on the diffusion coefficients. Furthermore, we display explicitly the peculiarities of the cluster-size distribution in one dimension.