On Concentrated Surface Loads and Green's functions in the Toupin-Mindlin theory of Strain-Gradient Elasticity

The two-dimensional Green's functions are derived for the half-plane in the context of the complete Toupin-Mindlin theory of isotropic strain-gradient elasticity. Two types of Green's functions exist for a concentrated force and a concentrated force dipole acting upon the surface of a traction-free half-plane. Our purpose is to examine the possible deviations from the predictions of classical theory of elasticity as well as from the simplified strain-gradient theory, which is frequently utilized in the last decade for the solution of boundary value problems. Of special importance is the behavior of the new solutions near to the point of application of the loads where pathological singularities and discontinuities exist in the classical solutions. The boundary value problems are attacked with the aid of the Fourier transform and exact full-field solutions are provided. Our results indicate that in all cases the displacement field is bounded and continuous at the point of application of the concentrated loads. The new solutions show therefore a more natural material response. For the concentrated force problem, both displacements and strains are found to be bounded, whereas the strain-gradients exhibit a logarithmic singularity. Thus, in marked contrast with the classical elasticity solution, a finite strain energy is contained within any finite portion of the body. On the other hand, in the case of the concentrated dipole force, the strains are logarithmically singular and the strain gradients exhibit a Cauchy type singularity. The nature of the boundary conditions in strain-gradient elasticity is highlighted through the solution of the pertinent boundary value problems. Finally, based on our analytical solution, the role of edge forces in strain-gradient elasticity is elucidated employing simple equilibrium considerations

Dust drift during sowing of maize - effects on honey bees

Background: Bee poisoning incidents in southern Germany in 2008 revealed drift of insecticidal dusts of treated maize seed during sowing on adjacent areas with flowering bee forage plants as a considerable route of exposure. Consequently, improvements have been proposed for seed dressing quality regarding dust abrasion taking into account residue content of dust and for the sowing techniques as possible risk mitigation measures. To assess potential effects on honey bee colonies following insecticidal dust drift on adjacent non-target areas, in 2010 and 2011 two large-scale drift experiments were carried out during maize sowing using seed batches from two different years (2010: seed batch from 2008; 2011: seed batch from 2011). Results: Despite improvements of seed dressing quality regarding dust abrasion comparing the two seed batches (Heubach value 0.86 in 2010 and 0.45 in 2011) and the use of a precision air seeder with drift reducing deflector, in both experiments bee mortality was clearly increased, especially in semifield conditions. Conclusions: Drift of insecticidal dusts during sowing of maize may result in a risk for honey bees in field conditions. To exclude adverse effects on bees, especially during sowing of maize further improvements of seed treatment quality and machinery is needed. Keywords: maize, seed treatment, clothianidin, dust drift, honey bee poisonin

Validation of an automated ELISA system for detection of antibodies to Aleutian mink disease virus using blood samples collected in filter paper strips

Peer reviewe

Phase 1 clinical study of an embryonic stem cell-derived retinal pigment epithelium patch in age-related macular degeneration

Age-related macular degeneration (AMD) remains a major cause of blindness, with dysfunction and loss of retinal pigment epithelium (RPE) central to disease progression. We engineered an RPE patch comprising a fully differentiated, human embryonic stem cell (hESC)-derived RPE monolayer on a coated, synthetic basement membrane. We delivered the patch, using a purpose-designed microsurgical tool, into the subretinal space of one eye in each of two patients with severe exudative AMD. Primary endpoints were incidence and severity of adverse events and proportion of subjects with improved best-corrected visual acuity of 15 letters or more. We report successful delivery and survival of the RPE patch by biomicroscopy and optical coherence tomography, and a visual acuity gain of 29 and 21 letters in the two patients, respectively, over 12 months. Only local immunosuppression was used long-term. We also present the preclinical surgical, cell safety and tumorigenicity studies leading to trial approval. This work supports the feasibility and safety of hESC-RPE patch transplantation as a regenerative strategy for AMD

Χριστούπολις, η βυζαντινή Καβάλα

Christoupolis, the Byzantine town-port of Eastern Macedonia and known nowadays as Kavala, is the subject of this paper. The main landmarks of Christoupolis’ historical evolution are studied according to Byzantine and Latin sources, archaeological finds (seals, sculptural fragments) and monastic documents.Christoupolis (the town of Christ) was the Byzantine nomination of the ancient Greek and Roman town of Neapolis, where Apostle Paul reached for the first time Europe in order to teach the religion of Christ. Although the name Christoupolis is first stated at the beginning of the 9th century, there were mentions of Neapolis in the works of the Byzantine authors Hierocles and Procopius. The important port of Christoupolis was devastated by the Normans in 1185 according to an inscription on a wall slab.  After the fall of Constantinople in 1204 Christoupolis was conquested by Lombard knights, who fought against Henri of Flanders (1206-1216), Latin emperor of Constantinople, during the winter of 1207/8. Christoupolis was liberated by the despot of Epirus Theodore Angelus Ducas Comnenus by the end of 1224 and in 1246 was part of the European provinces of John III Vatatses, emperor of Nicaea.During the 14th century the main milestones in the history of Christoupolis were the two Byzantine civil wars (1321-1328 and 1341-1347) and its conquest by the Turks. The citizens of this Byzantine port supported prince Andronicus III Palaeologus in the quarrel with his grandfather Andronicus II Palaeologus. In the second Byzantine civil war of the first quarter of this century Christoupolis sided with the emperor John V Palaeologus and against the aristocrat John Cantacuzenus. By the end of 1345 Christoupolis was the only town of the Eastern Macedonia that was not under the Serbian occupation of kral Stephan Dusan.The date of the conquest of Christoupolis by the Turks was probably 1383, when Drama and Serres were captured as well. In 1390 citizens of this port enforced, with a war ship, the Byzantine emperor Manuel II Palaeologus to recapture Constantinople from his nephew John VII Palaeologus. An attempt of a Venetian fleet to captured Christoupolis in 1425 has temporary success and the town remained under the Turkish control