Birch Reduction of Aromatic Compounds by Inorganic Electride [Ca2N]+•e- in an Alcoholic Solvent: An Analogue of Solvated Electrons.

Birch reduction of aromatic systems by solvated electrons in alkali metal-ammonia solutions is widely recognized as a key reaction that functionalizes highly stable π-conjugated organic systems. In spite of recent advances in Birch reduction with regard to reducing agent and reaction conditions, there remains an ongoing challenge to develop a simple and efficient Birch reaction under mild conditions. Here, we demonstrate that the inorganic electride [Ca2N]+•e- promotes the Birch reduction of polycyclic aromatic hydrocarbons (PAHs) and naphthalene under alcoholic solvent in the vicinity of room temperature as a solid-type analogy to solvated electrons in alkali metal ammonia solutions. The anionic electrons from electride [Ca2N]+•e- are transferred to PAHs and naphthalene via alcoholysis in a polar cosolvent medium. It is noteworthy that a high conversion yield to the hydrogenated products is ascribed to the extremely high electron transfer efficiency of 98%. This simple protocol utilizing an inorganic electride offers a direct and practical strategy for the reduction of aromatic compounds and provides an outstanding reducing agent for synthetic chemistry.

Application of variable threshold intensity to segmentation for white matter hyperintensities in fluid attenuated inversion recovery magnetic resonance images.

INTRODUCTION: White matter hyperintensities (WMHs) are regions of abnormally high intensity on T2-weighted or fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI). Accurate and reproducible automatic segmentation of WMHs is important since WMHs are often seen in the elderly and are associated with various geriatric and psychiatric disorders. METHODS: We developed a fully automated monospectral segmentation method for WMHs using FLAIR MRIs. Through this method, we introduce an optimal threshold intensity (I O ) for segmenting WMHs, which varies with WMHs volume (V WMH), and we establish the I O -V WMH relationship. RESULTS: Our method showed accurate validations in volumetric and spatial agreements of automatically segmented WMHs compared with manually segmented WMHs for 32 confirmatory images. Bland-Altman values of volumetric agreement were 0.96 ± 8.311 ml (bias and 95 % confidence interval), and the similarity index of spatial agreement was 0.762 ± 0.127 (mean ± standard deviation). Furthermore, similar validation accuracies were obtained in the images acquired from different scanners. CONCLUSIONS: The proposed segmentation method uses only FLAIR MRIs, has the potential to be accurate with images obtained from different scanners, and can be implemented with a fully automated procedure. In our study, validation results were obtained with FLAIR MRIs from only two scanner types. The design of the method may allow its use in large multicenter studies with correct efficiency.

Identifying the Correlation between Structural Parameters and Anisotropic Magnetic Properties in IMnV Semiconductors: A Possible Room-Temperature Magnetism.

Layer-structured materials are of central importance in a wide range of research fields owing to their unique properties originating from their two dimensionality and anisotropy. Herein, quasi-2D layer-structured IMnV (I: alkali metals and V: pnictogen elements) compounds are investigated, which are potential antiferromagnetic (AFM) semiconductors. Single crystals of IMnV compounds are successfully grown using the self-flux method and their electronic and magnetic properties are analyzed in correlation with structural parameters. Combined with theoretical calculations, the structural analysis indicates that the variation in the bonding angle between VMnV is responsible for the change in the orbital hybridization of Mn and V, predominantly affecting their anisotropic semiconducting properties. Anisotropy in the magnetic properties is also found, where AFM ordering is expected to occur in the in-plane direction, as supported by spin-structure calculations. Furthermore, a possible ferromagnetic (FM) transition is discussed in relation to the vacancy defects. This study provides a candidate material group for AFM and FM spintronics and a basis for exploring magnetic semiconductors in quasi-2D layer-structured systems.

Construction and Validation of Brain MRI Templates from a Korean Normal Elderly Population.

OBJECTIVE: This study aimed to construct a Korean normal elderly brain template (KNE96) using Korean elderly individuals for use in brain MRI studies and to validate it. METHODS: We used high-resolution 3.0T T1 structural MR images from 96 Korean normal elderly individuals (M/F=48/48), aged 60 years or older (M=69.5±6.2 years, F=70.1±7.0 years), for constructing the KNE96 template. The KNE96 template was validated by comparing the registration-induced deformations between the KNE96 and ICBM152 templates using different MR images from 48 Korean normal elderly individuals (M/F=24/24), aged 60 years or older (M=71.5±5.9 years, F=72.8±5.1 years). We used the magnitude of displacement vectors (mag-displacement) and log of Jacobian determinants (log-Jacobian) to quantify the deformation produced during registration process to templates. RESULTS: The mag-displacement and log-Jacobian of the registration were much smaller using the KNE96 template than with the ICBM152 template in most brain regions. There was a prominent difference in the significant averaged differences (SADs) of the mag-displacement and log-Jacobian between the KNE96 and ICBM152 at the superior, medial, and middle frontal gyrus, the lingual, inferior, middle, and superior occipital gyrus, and the caudate and thalamus. CONCLUSION: This study suggests that templates constructed from Asian populations, such as the KNE96, may be more desirable than those from Caucasian populations, like the ICBM152, in computational neuroimaging studies that measure and compare anatomical features of the frontal and occipital lobe, thalamus and caudate.