3,3-Disubstituted allylic boronic esters are not sufficiently reactive to react with ketones and imines. However, they can be converted into the corresponding borinic esters by the sequential addition of nBuLi and TFAA. These reactive intermediates possess the perfect balance between reactivity and configurational stability. Their enhanced reactivity allows the highly selective allylation of bo...

Four cubic compounds are reported that contain the supertetrahedral cluster [M(4)Sn(4)S(17)](10)(-) where M = Mn, Fe, Co, Zn. The cluster features a central quadruply bridging sulfide ion (mu(4)-S) that holds together four divalent M atoms in a tetrahedral arrangement. This core is capped with four tridentate [SnS(4)](4)(-) fragments to complete the structure.

Potassium channels have a very wide distribution of single-channel conductance, with BK type Ca(2+)-activated K(+) channels having by far the largest. Even though crystallographic views of K(+) channel pores have become available, the structural basis underlying BK channels' large conductance has not been completely understood. In this study we use intracellularly applied quaternary ammonium co...

it is a very short time that the quaternaries period in geology and physical geography's knowledge has occupied a very important place. during this period, the earth has suffered consecutive freezing that has been accompanied by tides and alternate erosion and sedimentation. sedimentary successions have recorded valuable evidence of changes with very accurate details. the study of these sedimen...

A new germanium(II) phosphate, sodium tetra-germanium tris-(phosphate), Na[Ge(4)(PO(4))(3)], has been synthesized by a solid-state reaction. The compound is isotypic with A[Sn(4)(PO(4))(3)] (A = Na, K, NH(4)). It features a [Ge(4)(PO(4))(3)](-) framework made up of GeO(3) pyramids and PO(4) tetra-hedra, which are linked by shared corners, yielding a three-dimensional structure. The crystal stud...

The title compound, C(18)H(24)I(2), has an adamantanoid structure with tetra-hedral cages having four C atoms lying on the same plane [(I-)C-C-C-C(-I) torsion angle = 0°]. The plane is extended by the two I atoms, each having a deviation of 1.0 (6) Å [C-C-C-I torsion angle = 178.9 (4)°]. The central C-C bond connecting the two quaternary carbons seems enlarged [1.593 (9) Å] in comparison to the...

Organocatalytic asymmetric Michael reactions of fluorinated nucleophiles with nitroolefins catalyzed by Cinchona alkaloid-derived thiourea catalysts generated the desired Michael products containing vicinal fluorinated quaternary and tertiary chiral centers with exceptional enantioselectivity.

For many procedures used in behavioral pharmacology, the intracerebroventricular (ICV) route of drug administration is infrequently used due, in part, to the lack of a reliable technique for determining cannula patency in vivo. This study describes an in vivo technique for assessing ICV cannula patency in pigeons. The technique was applied in an experiment designed to evaluate several drugs, wh...

A generic M-ary continuous phase modulation (CPM) scheme, with a modulation index of h = 1/M, can be decomposed into a continuous-phase encoder (CPE) followed by a memoryless modulator (MM), where the CPE is linear over the ring of integers modulo M. By using a channel encoder (CE), which is a convolutional encoder, to operate over the same ring of integers modulo M, the CE and the CPE can be c...

We improved the performance of a functional near-infrared spectroscopy (fNIRS)-based brain-computer interface based on relatively short task duration and multiclass classification. A custom-built eight-channel fNIRS system was used over the motor cortex areas in both hemispheres to measure the hemodynamic responses evoked by four different motor tasks (overt execution of arm lifting and knee ex...