Insights into the chemical composition of Equisetum hyemale by high resolution Raman imaging

Equisetaceae has been of research interest for decades, as it is one of the oldest living plant families, and also due to its high accumulation of silica up to 25% dry wt. Aspects of silica deposition, its association with other biomolecules, as well as the chemical composition of the outer strengthening tissue still remain unclear. These questions were addressed by using high resolution (<1 μm) Confocal Raman microscopy. Two-dimensional spectral maps were acquired on cross sections of Equisetum hyemale and Raman images calculated by integrating over the intensity of characteristic spectral regions. This enabled direct visualization of differences in chemical composition and extraction of average spectra from defined regions for detailed analyses, including principal component analysis (PCA) and basis analysis (partial least square fit based on model spectra). Accumulation of silica was imaged in the knobs and in a thin layer below the cuticula. In the spectrum extracted from the knob region as main contributions, a broad band below 500 cm−1 attributed to amorphous silica, and a band at 976 cm−1 assigned to silanol groups, were found. From this, we concluded that these protrusions were almost pure amorphous, hydrated silica. No silanol group vibration was detected in the silicified epidermal layer below and association with pectin and hemicelluloses indicated. Pectin and hemicelluloses (glucomannan) were found in high levels in the epidermal layer and in a clearly distinguished outer part of the hypodermal sterome fibers. The inner part of the two-layered cells revealed as almost pure cellulose, oriented parallel along the fiber

Language disorders subsequent to left cerebellar lesions: A case for bilateral cerebellar involvement in language?

Background: Crossed cerebello-cerebral diaschisis, reflecting a functional depression of supratentorial language areas due to reduced input via cerebello-cortical pathways, may represent the neuropathological mechanism responsible for language deficits associated with cerebellar pathology. Although it has been proposed that language is lateralized to the right cerebellar hemisphere, recent clinical and neuroimaging studies suggest that the cerebellum may bilaterally influence the regulation of language, with the left cerebellar hemisphere also contributing to the mediation of language via ipsilateral cerebello-cortical pathways. Aims: The aim of the study was to determine the effect of left primary cerebellar lesions on general as well as higher-level language function. Methods and Procedures: Linguistic profiles of a group of ten individuals with left primary cerebellar lesions were compared with those of a group of non-neurologically impaired controls matched for age, gender and level of education. Outcomes and Results: The findings confirmed that higher-level language deficits may result from left primary cerebellar lesions possibly as a consequence of ipsilateral cerebral diaschisis. Conclusions: The results challenge the notion of a right lateralized cerebellum and support a role for the left as well as the right cerebellar hemisphere in the regulation of language function. Copyright (c) 2007 S. Karger AG, Basel