Phenotypic Differences in a PRPH2 Mutation in Members of the Same Family Assessed with OCT and OCTA

Choroidal dystrophies comprise a group of chorioretinal degenerations. However, the different findings observed among these patients make it difficult to establish a correct clinical diagnosis. The objective of this study was to characterize new clinical findings by optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) in these patients. Four family members with a PRPH2 gene mutation (p.Arg195Leu) were included. OCT was performed at the macula, and the thickness of the outer and inner retina, total retina, and choroid was measured. The features of the vascular network were analyzed by OCTA. Patients showed a decreased outer nuclear layer in the avascular area compared with the controls. Two patients presented greater foveal and parafoveal degeneration of the outer retina, whereas the most degenerated area in the rest was the perifovea. Disruption of the third outer band at the foveola is one of the first-altered outer bands. Slow blood flow areas or capillary dropout were main signs in the deep capillary plexus. Microaneurysms were frequently observed in less degenerated retinas. Vascular loops and intraretinal microvascular abnormalities (IRMAs) were present in the superficial plexus. Extensive degeneration of the choriocapillaris was detected. Phenotypic differences were found between patients: two showed central areolar choroidal dystrophy and the rest had extensive chorioretinal atrophy. These signs observed in OCT and OCTA can help to more appropriately define the clinical disease in patients with choroidal dystrophies.

Metasediments Covering Ophiolites in the HP Internal Belt of the Western Alps: Review of Tectono-Stratigraphic Successions and Constraints for the Alpine Evolution

Ophiolites of the Alpine belt derive from the closure of the Mesozoic Tethys Ocean that was interposed between the palaeo-Europe and palaeo-Adria continental plates. The Alpine orogeny has intensely reworked the oceanic rocks into metaophiolites with various metamorphic imprints. In the Western Alps, metaophiolites and continental-derived units are distributed within two paired bands: An inner band where Alpine subduction-related high-pressure (HP) metamorphism is preserved, and an outer band where blueschist to greenschist facies recrystallisation due to the decompression path prevails. The metaophiolites of the inner band are hugely important not just because they provide records of the prograde tectonic and metamorphic evolution of the Western Alps, but also because they retain the signature of the intra-oceanic tectono-sedimentary evolution. Lithostratigraphic and petrographic criteria applied to metasediments associated with HP metaophiolites reveal the occurrence of distinct tectono-stratigraphic successions including quartzites with marbles, chaotic rock units, and layered calc schists. These successions, although sliced, deformed, and superposed in complex ways during the orogenic stage, preserve remnants of their primary depositional setting constraining the pre-orogenic evolution of the Jurassic Tethys Ocean.

Cooled Turbine Cantilevered Nozzle Mounting and Sealing System

Small advanced turboprop and turboshaft engines, with two-stage high-pressure turbine (HPT), need to meet several challenges. Described herein is an exemplary solution adopted for a cantilevered HPT nozzle mounting and sealing system that helped to meet requirements for size constraint and sealing of split lines and mounting features. Since clearances do not scale down with engine size due to manufacturing tolerances, there is a very limited space available between first and second stage rotors to secure HPT nozzle and to provide means of cooling air supply. Due to small diameters, cavities and size of the parts and assembly access becomes very difficult and precluded the use of typical solutions – like supply air spooilers – known from bigger engines. Relatively larger clearances require also efficient solution for sealing leakage, which was achieved by means of high-temperature braided “rope seals”. The nozzle segments have weight effective hook-type outer band mounting to HPT outer casing and are axially retained by HPT shroud with a snap ring. The hook cavities were used as pockets for rope seals that are subsequently compressed during assembly making it more difficult. However, by special design of the pockets and parts engagement sequence, the assembly process was optimized even though it is so called blind assembly. The sealing system function is not only reducing leakages that are detrimental to a turbine efficiency, but also allow for pressurizing the cavity between the nozzle outer band and HPT outer casing with cooling air thus preventing from hot gas ingestion by higher back-flow margin (BFM) resulting in higher durability of the turbine.

State Action and the Constitution's Middle Band

On conventional accounts, the state action doctrine is dichotomous. When the government acts, constitutional limits take hold and the government action is invalid if those limits are exceeded. When the government fails to act, the state action doctrine leaves decisions to individuals, who are permitted to violate what would otherwise be constitutional constraints. It turns out though that the modern state action doctrine creates three rather than two domains. There is indeed a private, inner band where there is thought to be insufficient government action to trigger constitutional constraints, but often there is also a public, outer band where there is too much state action for the Constitution to apply. The Constitution takes hold only in a middle band—the Goldilocks band—sandwiched between these two domains. For constitutional limitations to have force, the government must act just enough—but not too much. This Article’s first aim is to identify and describe this puzzling structure. It also examines a variety of doctrinal principles that produce and, perhaps, justify the state action doctrine’s three bands. The Article then argues that these seemingly disparate principles are all related to the special constitutional problems produced by the emergence of the middle band of government regulation. Finally, the Article concludes with some brief speculation about whether the modern tripartite structure can survive.