On Ceramic Parts Fabricated Rapid Prototyping Machine Based on Ceramic Laser Fusion

Conventional ceramic manufacture processes are not feasible to make ceramic parts with complex shape because of restrictions such as high tooling cost, time consuming and skillful workmanship. A new facility taking advantage of patented Ceramic Laser Fusion (CLF) technology to fabricate complex ceramic parts automatically is developed. According to the samples made by CLF machine, they are verified that hollow and over hung structures can be supported by solid green portion and complex ceramic parts can be fabricated. Apparently, this facility could promote the applications of ceramic materials, such as direct fabrication of ceramic shell mold.Mechanical Engineerin

Animal Models of Diabetic Retinopathy (Part 2)

Diabetic retinopathy (DR) is one of the leading causes of preventable vision impairment and blindness in the working-age population worldwide. Numerous animal models have been developed for therapeutic drug screening and to further increase our understanding of the molecular and cellular pathological processes involved in DR. Following our discussion of mouse models in “Animal Models of Diabetic Retinopathy Part 1,” we describe the cellular, molecular, and morphological features of both rodent and nonrodent models of DR and their respective advantages and limitations in this chapter. To date, no animal model can holistically reproduce the pathological progression of human DR; most only display early or advanced lesions of DR. However, a thorough understanding of genotypic and phenotypic expressions of existing models will facilitate researchers’ selection of the appropriate model to simulate their desired clinical scenarios

Coherent States in Null-Plane Q.E.D

Light front field theories are known to have the usual infra-red divergences of the equal time theories, as wellas new `spurious' infra-red divergences. The formar kind of IR divergences are usually treated by giving a small mass to the gauge particle. An alternative method to deal with these divergences is to calculate the transition matrix elements in a coherent state basis. In this paper we present, as a model calculation the lowest order correction to the three point vertex in QED using a coherent state basis in the light cone formalism. The relevant transition matrix element is shown to be free of the true IR divergences up to $O(e^2)$.Comment: 20 pages and two figures, REVTEX, ITP-SB-93-7

Interfaces with a single growth inhomogeneity and anchored boundaries

The dynamics of a one dimensional growth model involving attachment and detachment of particles is studied in the presence of a localized growth inhomogeneity along with anchored boundary conditions. At large times, the latter enforce an equilibrium stationary regime which allows for an exact calculation of roughening exponents. The stochastic evolution is related to a spin Hamiltonian whose spectrum gap embodies the dynamic scaling exponent of late stages. For vanishing gaps the interface can exhibit a slow morphological transition followed by a change of scaling regimes which are studied numerically. Instead, a faceting dynamics arises for gapful situations.Comment: REVTeX, 11 pages, 9 Postscript figure

Thermodynamic properties of the two-dimensional S=1/2 Heisenberg antiferromagnet coupled to bond phonons

By applying a quantum Monte Carlo procedure based on the loop algorithm we investigate thermodynamic properties of the two-dimensional antiferromagnetic S=1/2 Heisenberg model coupled to Einstein phonons on the bonds. The temperature dependence of the magnetic susceptibility, mean phonon occupation numbers and the specific heat are discussed in detail. We study the spin correlation function both in the regime of weak and strong spin phonon coupling (coupling constants g=0.1, w=8J and g=2, w=2J, respectively). A finite size scaling analysis of the correlation length indicates that in both cases long range Neel order is established in the ground state.Comment: 10 pages, 13 figure

Small-scale solar magnetic fields

As we resolve ever smaller structures in the solar atmosphere, it has become clear that magnetism is an important component of those small structures. Small-scale magnetism holds the key to many poorly understood facets of solar magnetism on all scales, such as the existence of a local dynamo, chromospheric heating, and flux emergence, to name a few. Here, we review our knowledge of small-scale photospheric fields, with particular emphasis on quiet-sun field, and discuss the implications of several results obtained recently using new instruments, as well as future prospects in this field of research.Comment: 43 pages, 18 figure

Assessment of hypermucoviscosity as a virulence factor for experimental Klebsiella pneumoniae infections: comparative virulence analysis with hypermucoviscosity-negative strain

Background: Klebsiella pneumoniae displaying the hypermucoviscosity (HV) phenotype are considered more virulent than HV-negative strains. Nevertheless, the emergence of tissue-abscesses-associated HV-negative isolates motivated us to re-evaluate the role of HV-phenotype. Results: Instead of genetically manipulating the HV-phenotype of K. pneumoniae, we selected two clinically isolated K1 strains, 1112 (HV-positive) and 1084 (HV-negative), to avoid possible interference from defects in the capsule. These well-encapsulated strains with similar genetic backgrounds were used for comparative analysis of bacterial virulence in a pneumoniae or a liver abscess model generated in either naive or diabetic mice. In the pneumonia model, the HV-positive strain 1112 proliferated to higher loads in the lungs and blood of naive mice, but was less prone to disseminate into the blood of diabetic mice compared to the HV-negative strain 1084. In the liver abscess model, 1084 was as potent as 1112 in inducing liver abscesses in both the naive and diabetic mice. The 1084-infected diabetic mice were more inclined to develop bacteremia and had a higher mortality rate than those infected by 1112. A mini-Tn5 mutant of 1112, isolated due to its loss of HV-phenotype, was avirulent to mice. Conclusion: These results indicate that the HV-phenotype is required for the virulence of the clinically isolated HV-positive strain 1112. The superior ability of the HV-negative stain 1084 over 1112 to cause bacteremia in diabetic mice suggests that factors other than the HV phenotype were required for the systemic dissemination of K. pneumoniae in an immunocompromised setting

Pion interferometry in Au+Au collisions at sqrt[sNN]=200GeV

We present a systematic analysis of two-pion interferometry in Au+Au collisions at sqrt[sNN]=200GeV using the STAR detector at Relativistic Heavy Ion Collider. We extract the Hanbury-Brown and Twiss radii and study their multiplicity, transverse momentum, and azimuthal angle dependence. The Gaussianness of the correlation function is studied. Estimates of the geometrical and dynamical structure of the freeze-out source are extracted by fits with blast-wave parametrizations. The expansion of the source and its relation with the initial energy density distribution is studied