Gray matter imaging in multiple sclerosis: what have we learned?

At the early onset of the 20th century, several studies already reported that the gray matter was implicated in the histopathology of multiple sclerosis (MS). However, as white matter pathology long received predominant attention in this disease, and histological staining techniques for detecting myelin in the gray matter were suboptimal, it was not until the beginning of the 21st century that the true extent and importance of gray matter pathology in MS was finally recognized. Gray matter damage was shown to be frequent and extensive, and more pronounced in the progressive disease phases. Several studies subsequently demonstrated that the histopathology of gray matter lesions differs from that of white matter lesions. Unfortunately, imaging of pathology in gray matter structures proved to be difficult, especially when using conventional magnetic resonance imaging (MRI) techniques. However, with the recent introduction of several more advanced MRI techniques, the detection of cortical and subcortical damage in MS has considerably improved. This has important consequences for studying the clinical correlates of gray matter damage. In this review, we provide an overview of what has been learned about imaging of gray matter damage in MS, and offer a brief perspective with regards to future developments in this field

Synthesis, properties, and photopolymerization of liquid-crystalline oxetanes:Application in transflective liquid-crystal displays

\u3cp\u3eMixtures of liquid-crystalline di-oxetanes and mono-oxetanes are made for the purpose of making birefringent films by photopolymerization. The composition of a di-oxetane mixture that forms spin-coated films of planarly aligned nematic monomers is reported. These films are photopolymerized in air. The molecular order of the monomers can be changed on the microscale to form thin films with alternating birefringent and isotropic parts by using a combination of photopolymerization and heating. The interface observed between the birefringent and isotropic 10 μm × 10 μm domains is very sharp and the films show hardly any surface corrugation. In addition, the polymerized films are thermally stable, making them very suitable for use as patterned thin-film retarders in high-performance transflective liquid-crystal displays (LCDs) which satisfy customer demand for displays that are brighter and thinner and that deliver better optical performance than conventional LCDs with an external non-patterned retarder.\u3c/p\u3

Transflective liquid crystal displays with patterned optical layer

\u3cp\u3eA transflective liquid crystal display comprising a plurality of pixels, each pixel comprising a liquid crystal layer (3) sandwiched between a front substrate (1) and a back substrate (2), and an optical layer (7) comprising a birefringent material, said pixels being divided into at least one transmissive (5) and at least one reflective subpixel (4), and said optical layer (7) being at least partly sandwiched between the liquid crystal layer (3) and one of said front substrate (1) or back substrate (2), and being patterned into domains (8, 9), each domain covering at least part of a reflective subpixel (4) or at least part of a transmissive subpixel (5).\u3c/p\u3

Technologies towards patterned optical foils applied to transflective LCDs

\u3cp\u3eFor better front-of-screen performance for transflective LCDs, a technology with extra free optimization parameters for the optical stack is needed. Thin wet coatable retarders which enable adjustment of the optical activity on the (sub)pixel level have been developed. Isotropic domains have been created in nematic retardation films by thermal patterning or photopatterning. Employing such a patterned retarder in a transflective LCD leads to an LCD that is lighter and thinner with good reflectivity, high transmission, and low chromaticity at all gray levels and wide viewing angles. The patterned thin-film technology has been proven to be versatile and applicable in various LCD designs.\u3c/p\u3