Chemical analysis and computed tomography of metallic inclusions in Roman glass to unveil ancient coloring methods

This paper describes the analysis of two near-spherical metallic inclusions partially incorporated within two Roman raw glass slags in order to elucidate the process that induced their formation and to determine whether their presence was related to ancient glass colouring processes. The theory of metallic scraps or powder being used in Roman times for glass-making and colouring purposes is widely accepted by the archaeological scientific community, although the assumption has been mainly based on oral traditions and documented medieval practices of glass processing. The analysis of the two inclusions, carried out by X-ray computed tomography, electrochemical analyses, and scanning electron microscopy, revealed their material composition, corrosion and internal structure. Results indicate that the two metallic bodies originated when, during the melting phase of glass, metal scraps were added to colour the material: the colloidal metal–glass system reached then a supersaturation condition and the latter ultimately induced metal expulsion and agglomeration. According to the authors’ knowledge, these two inclusions represent the first documented and studied finds directly associated with the ancient practise of adding metallic agents to colour glass, and their analysis provides clear insights into the use of metallic waste in the glass colouring process.

Kinetics of self-assembly of inclusions due to lipid membrane thickness interactions

Self-assembly of proteins on lipid membranes underlies many important processes in cell biology, such as, exo- and endo-cytosis, assembly of viruses, etc. An attractive force that can cause self-assembly is mediated by membrane thickness interactions between proteins. The free energy profile associated with this attractive force is a result of the overlap of thickness deformation fields around the proteins. The thickness deformation field around proteins of various shapes can be calculated from the solution of a boundary value problem and is relatively well understood. Yet, the time scales over which self-assembly occurs has not been explored. In this paper we compute this time scale as a function of the initial distance between two inclusions by viewing their coalescence as a first passage time problem. The first passage time is computed using both Langevin dynamics and a partial differential equation, and both methods are found to be in excellent agreement. Inclusions of three different shapes are studied and it is found that for two inclusions separated by about hundred nanometers the time to coalescence is hundreds of milliseconds irrespective of shape. Our Langevin dynamics simulation of self-assembly required an efficient computation of the interaction energy of inclusions which was accomplished using a finite difference technique. The interaction energy profiles obtained using this numerical technique were in excellent agreement with those from a previously proposed semi-analytical method based on Fourier-Bessel series. The computational strategies described in this paper could potentially lead to efficient methods to explore the kinetics of self-assembly of proteins on lipid membranes.Author summarySelf-assembly of proteins on lipid membranes occurs during exo- and endo-cytosis and also when viruses exit an infected cell. The forces mediating self-assembly of inclusions on membranes have therefore been of long standing interest. However, the kinetics of self-assembly has received much less attention. As a first step in discerning the kinetics, we examine the time to coalescence of two inclusions on a membrane as a function of the distance separating them. We use both Langevin dynamics simulations and a partial differential equation to compute this time scale. We predict that the time to coalescence is on the scale of hundreds of milliseconds for two inclusions separated by about hundred nanometers. The deformation moduli of the lipid membrane and the membrane tension can affect this time scale.

Discovery and description of the first known fossil Signiphoridae (Hymenoptera, Chalcidoidea)

Chartocerus azizaesp. nov. is described as the first known fossil from the family Signiphoridae, based on two inclusions in the same piece of Eocene Baltic amber (36.7–48.5 million years ago). Implications of the morphology of C. azizae are discussed, indicating that it should be placed in Chartocerus.

Two interacting non-elliptical rigid harmonic inclusions loaded by couples

We use conformal mapping techniques to design two interacting non-elliptical rigid inclusions, each of which is loaded by a couple, which ensure the so-called ?harmonic condition? in which the original mean stress in the matrix remains undisturbed after the introduction of the inclusions. We show that for prescribed Poisson?s ratio and corresponding geometric parameters, several restrictions are necessary on the external loadings to ensure the harmonic condition. It is seen from our analysis that: (i) the interfacial and hoop stresses are uniformly distributed along each of the inclusion-matrix interfaces; (ii) the interfacial normal and hoop stresses along the two interfaces are completely determined by the Poisson?s ratio and the constant mean stress in the matrix whilst the interfacial tangential stress along the two interfaces can be completely determined by the moments of the couples and the areas of the two inclusions; (iii) the existence of the applied couples will influence the non-elliptical shapes of the two rigid harmonic inclusions when the moment to area ratios for the two inclusions differ.

Three-Dimensional Holographic Electromagnetic Imaging for Accessing Brain Stroke

The authors recently developed a two-dimensional (2D) holographic electromagnetic induction imaging (HEI) for biomedical imaging applications. However, this method was unable to detect small inclusions accurately. For example, only one of two inclusions can be detected in the reconstructed image if the two inclusions were located at the same XY plane but in different Z-directions. This paper provides a theoretical framework of three-dimensional (3D) HEI to accurately and effectively detect inclusions embedded in a biological object. A numerical system, including a realistic head phantom, a 16-element excitation sensor array, a 16-element receiving sensor array, and image processing model has been developed to evaluate the effectiveness of the proposed method for detecting small stroke. The achieved 3D HEI images have been compared with 2D HEI images. Simulation results show that the 3D HEI method can accurately and effectively identify small inclusions even when two inclusions are located at the same XY plane but in different Z-directions. This preliminary study shows that the proposed method has the potential to develop a useful imaging tool for the diagnosis of neurological diseases and injuries in the future.

Uniform strain fields inside multiple inclusions in an elastic infinite plane under anti-plane shear

This paper constructs multiple elastic inclusions with prescribed uniform internal strain fields embedded in an infinite matrix under given uniform remote anti-plane shear. The method used is based on the sufficient and necessary conditions imposed on the boundary values of a holomorphic function, which guarantee the existence of the holomorphic function in a multiply connected region. The unknown shape of each of the multiple inclusions is characterized by a polynomial conformal mapping with a finite number of unknown coefficients. With the aid of Cauchy’s integral formula and Faber series, these unknown coefficients are determined by a system of nonlinear equations. Detailed numerical examples are shown for multiple inclusions with various prescribed uniform internal strain fields, for symmetrical inclusions and for inclusions whose shapes are independent of the remote loading, respectively. It is found that the admissible range of uniform internal strain fields for multiple inclusions is moderately larger than the admissible range of the uniform internal strain field for a single elliptical inclusion under the same remote loading. In particular, specific conditions on the prescribed uniform internal strain fields and elastic constants of the multiple inclusions are derived for the existence of symmetric inclusions and rotationally symmetrical inclusions. Moreover, for any two inclusions among multiple inclusions of shapes independent of the remote loading, it is shown that the ratio between the uniform internal strain fields inside the two inclusions equals a specific ratio determined by the shear moduli of the two inclusions and the matrix.

First caddisflies (Trichoptera) in Lower Cretaceous Lebanese amber

ABSTRACTLebanese amber contains a diverse biota from the Lower Cretaceous, and more than 150 families of arthropods have been reported as inclusions. Amongst these, caddisflies (Trichoptera) are very scarce inclusions, consisting of a few indeterminate fragments and only two inclusions that permit clear descriptions of new species. We describe the first two Trichoptera species from Lebanese amber, belonging respectively to Dipseudopsidae (Phylocentropus succinolebanensis n. sp.) and Ecnomidae (Ecnomus cretacia n. sp.). Previously, the oldest fossil representatives of both families were known from the Upper Cretaceous amber of New Jersey for Dipseudopsidae and from the Eocene Baltic amber for Ecnomidae.