Medeuro : the longing for identity and community among Maltese migrant settlers in North Africa

Based largely on materials held in the Service des Periodiques at the Bibliotheque Nationale de Tunisie in Tunis, and especially on content anaylsis of a 1930s newspaper Melita published in Sousse. this study explores the yearning for and the anguish of a cultural survivance among Maltese migrant settlers in North Africa, above all the retention of Maltese as a language of expression, affinity and identification, at a time when Maltese itself was experiencing a literary rebirth. However, such a campaign is undertaken in a 'non-Maltese' context, where moreover, in addition to separation and distance, the influence of European empires-the French, the British and the Italian-is pronounced, if not dominant, thus interfering with any continued loyalty to one mother tongue or mother country. Masterminding the intellectual push for a collective self-identity anchored in language, literature, history and religion, is a leading francophone litterateur whose family had settled in Algeria from the island of Gozo. What is also offered here, in the annotations, is a fairly comprehensive bibliography of Maltese migrant settlement in northern Africa with special reference to lesser known articles and other publications not available in English.peer-reviewe

Calcium Influx Rescues Adenylate Cyclase-Hemolysin from Rapid Cell Membrane Removal and Enables Phagocyte Permeabilization by Toxin Pores

Bordetella adenylate cyclase toxin-hemolysin (CyaA) penetrates the cytoplasmic membrane of phagocytes and employs two distinct conformers to exert its multiple activities. One conformer forms cation-selective pores that permeabilize phagocyte membrane for efflux of cytosolic potassium. The other conformer conducts extracellular calcium ions across cytoplasmic membrane of cells, relocates into lipid rafts, translocates the adenylate cyclase enzyme (AC) domain into cells and converts cytosolic ATP to cAMP. We show that the calcium-conducting activity of CyaA controls the path and kinetics of endocytic removal of toxin pores from phagocyte membrane. The enzymatically inactive but calcium-conducting CyaA-AC− toxoid was endocytosed via a clathrin-dependent pathway. In contrast, a doubly mutated (E570K+E581P) toxoid, unable to conduct Ca2+ into cells, was rapidly internalized by membrane macropinocytosis, unless rescued by Ca2+ influx promoted in trans by ionomycin or intact toxoid. Moreover, a fully pore-forming CyaA-ΔAC hemolysin failed to permeabilize phagocytes, unless endocytic removal of its pores from cell membrane was decelerated through Ca2+ influx promoted by molecules locked in a Ca2+-conducting conformation by the 3D1 antibody. Inhibition of endocytosis also enabled the native B. pertussis-produced CyaA to induce lysis of J774A.1 macrophages at concentrations starting from 100 ng/ml. Hence, by mediating calcium influx into cells, the translocating conformer of CyaA controls the removal of bystander toxin pores from phagocyte membrane. This triggers a positive feedback loop of exacerbated cell permeabilization, where the efflux of cellular potassium yields further decreased toxin pore removal from cell membrane and this further enhances cell permeabilization and potassium efflux

Crystal Structures from Powder Diffraction: Principles, Difficulties and Progress

The structure solution from powder diffraction has undergone an intense evolution during the last 20 years, but is far from being routine. Current challenges of powder crystallography include ab initio crystal structure determination on real samples of new materials with specific microstructures, characterization of intermediate reaction products from in situ, in operando studies and novel phases from in situ studies of phase diagrams. The intense evolution of electron diffraction in recent years, providing an experimental (precession) and theoretical (still under intense development) solution to strong dynamic scattering of electrons, smears the traditional frontier between poly- and single-crystal diffraction. Novel techniques like serial snapshot X-ray crystallography point in the same direction. Finally, for the computational chemistry, theoreticians hand-in-hand with crystallographers develop tools where the theory meets experiment for crystal structure refinement, which becomes an unavoidable step in the validation of crystal structures obtained from powder diffractio

Powder Pattern Decomposition with the Aid of Preferred Orientation - Use of the Whole Debye-Scherrer Ring

Method of the decomposition of overlapping reflections in a powder pattern with the aid of preferred orientation is tested on magnetically aligned samples using the effect of easy magnetization direction in hexagonal SmCo5 and TbCo5. Complete Debye-Scherrer rings, measured with an image plate detector, are integrated in different radial directions. The texture aided powder pattern decomposition results in correct values of structure amplitude

Direct space methods of crystal structure determination from powder diffraction applied to intermetallic compounds

Direct space methods of structure determination from powder diffraction of non-molecular compounds (inorganics, extended solids, intermetallic compounds etc.) are reviewed. They do not need powder pattern decomposition, and are based on a global optimization of a structural model to improve the agreement between the observed and calculated diffraction patterns. The success of the method depends very much on a proper modeling of the structure from building blocks. The modeling from larger building blocks improves the convergence of the global optimization algorithm by a factor of up to ten. The correctness of the building block like its rigidity, deformation, bonding distances and ligand identity must be examined carefully. Dynamical Occupancy Correction implemented in the direct space program FOX has shown to be useful when merging excess atoms, and even larger building blocks like coordination polyhedra. It allows also joining smaller blocks into larger ones in the case when the connectivity is not a priori evident from the structural model. The available computer programs working in direct space are listed

Powder Pattern Decomposition with the Aid of Preferred Orientation - Experimental Test

A method of decomposition of overlapping reflections in a powder pattern with the aid of preferred orientation is presented. Empirical preferred orientation correction with axial symmetry is used. The method is tested on several sets of simulated powder patterns

Crystal Structure of the B-type Dierbium Oxide <i>ortho</i>-Oxosilicate Er₂O[SiO₄]

The crystal structure of B-type Er2O[SiO4] has been determined by single crystal X-ray diffraction. It crystallizes with the (Mn,Fe)2[PO4]F type structure in the monoclinic space group C2/c (a = 14.366(2), b = 6.6976(6), c = 10.3633(16) Å, ß = 122.219(10)°, Z = 8) and shows anionic tetrahedral [SiO4]4– units and non-silicon-bonded O2– anions in distorted [OEr4]10+ tetrahedra. The [(Er1)O6+1] and [(Er2)O6] polyhedra form infinite chains which are connected by common edges