Glaucophanic metamorphism in Anglesey

Igneous and sedimentary rocks of Precambrian age in Southern Anglesey are in a low grade of metamorphism over most of the area. The history of the basic igneous rocks has been traced from the practically unmetamorphosed state, through the greenschist stage, to low grade epidote-amphibole-schist stage. The associated semipelites have been converted to muscovite-epidote-garnet schist. The occurrence of glaucophane and lawsonite within a restricted part of the area is of particular interest. Not all the epidote-amphibole schists have necessarily passed through all the stages of increasing metamorphism. The very fine grained nature of these rocks suggests that some of them may have arisen direct from lavas, without having had to pass through the chlorite-schist stage But along the transitional zone between glaucophane schists and greenschists there is evidence of amphibole growing at the expense of chlorite. The chemistry of the glaucophane-epidote schists is essentially the same as the chemistry of other basic rocks that do not contain glaucophane. The formation of glaucophane appears to depend on physical rather than chemical factors. It is suggested that glaucophane was formed in a restricted zone where the mean pressure was elevated, compared to the pressures in the rest of the area, as a result of tectonic overpressures

Graph theory analysis of resting-state functional magnetic resonance imaging in essential tremor.

Essential tremor (ET) is a neurological disease with both motor and non-motor manifestations; however, little is known about its underlying brain basis. Furthermore, the overall organization of the brain network in ET remains largely unexplored. We investigated the topological properties of brain functional network, derived from resting-state functional MRI data, in 23 ET patients vs. 23 healthy controls. Graph theory analysis was used to assess the functional network organization. At the global level, the functional network of ET patients was characterized by lower small-world values than healthy controls - less clustered functionality of the brain. At the regional level, compared with the healthy controls, ET patients showed significantly higher values of global efficiency, cost and degree, and a shorter average path length in the left inferior frontal gyrus (pars opercularis), right inferior temporal gyrus (posterior division and temporo-occipital part), right inferior lateral occipital cortex, left paracingulate, bilateral precuneus bilaterally, left lingual gyrus, right hippocampus, left amygdala, nucleus accumbens bilaterally, and left middle temporal gyrus. In addition, ET patients showed significant higher local efficiency and clustering coefficient values in the frontal medial cortex bilaterally, subcallosal cortex, posterior cingulate, parahippocampal gyri bilaterally (posterior division), right lingual gyrus, right cerebellar flocculus, right postcentral gyrus, right inferior semilunar lobule of cerebellum and culmen of vermis. In conclusion, the efficiency of the overall brain functional network in ET is disrupted. Further, our results support the concept that ET is a disorder that disrupts widespread brain regions, including those outside of the brain regions responsible for tremor.pre-print1168 K

Essential Tremor and Parkinson’s Disease: Exploring the Relationship

Background: There is longstanding controversy surrounding the possible link between essential tremor (ET) and Parkinson’s disease (PD). Inconsistent and unreliable diagnostic criteria may in part account for some of the difficulties in defining the relationship between these two common movement disorders. Methods: References for this systematic review were identified using PubMed with the search terms “essential tremor” AND “Parkinson’s disease” with articles published in English between 1960 and September 2018 included. Results: In this review we provide evidence that some patients diagnosed with ET have an increased risk of developing PD years or decades after onset of action tremor. There are several still unresolved questions about the link between the two disorders including lack of verifiable diagnostic criteria for the two disorders and marked overlap in phenomenology. Here we review clinical, epidemiologic, imaging, pathologic, and genetic studies that address the ET–PD relationship. Several lines of evidence support the association between ET and PD, including overlapping motor and non-motor features, relatively high prevalence of rapid eye movement sleep behavior disorder (26–43%) in ET patients, increased prevalence of PD in patients with longstanding antecedent ET, increased prevalence of ET in family members of patients with PD, and the presence of Lewy bodies in the brains of some ET patients (15–24%). Discussion: There is a substantial body of evidence supporting the association between ET and PD within at least a subset of patients, although the nature and possible pathogenic mechanisms of the relationship are not well understood

SYNTHESIS OF 5-SUBSTITUTED PYRIMIDINES.

SYNTHESIS OF 5-SUBSTITUTED PYRIMIDINES