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Opposite Hemisphere (opposite + hemisphere)
Selected AbstractsReperfusion normalizes motor activation patterns in large-vessel disease,ANNALS OF NEUROLOGY, Issue 2 2009Mohamad Chmayssani MD Objective Hemodynamic impairment in one hemisphere has been shown to trigger ipsilateral motor activation in the opposite hemisphere on functional imaging. We hypothesized that reversing the hypoperfusion would normalize the motor activation pattern. Methods We studied four patients with high-grade stenosis and impaired vasomotor reactivity (VMR) but no stroke. Functional magnetic resonance imaging motor activation pattern before and after VMR normalization was compared with seven healthy control subjects scanned at an interval of 3 months using voxel-wise statistical parametric maps and region of interest analysis. Subjects performed a repetitive hand closure task in synchrony with 1Hz metronome tone. We used repeated-measures analysis of variance to compute the interaction between group (patients/control subjects) and time by obtaining the average blood oxygen level dependent signal of three motor regions of interest in each hemisphere. Results Two patients normalized their VMR after spontaneous resolution of dissection, and two after revascularization procedures. Both voxel-wise statistical maps and region of interest analysis showed that VMR normalization was associated in each case with a reduction in the atypical activation in the hemisphere opposite to the previously hypoperfused hemisphere (p < 0.001). Interpretation In the presence of a physiological stressor such as hypoperfusion, the brain is capable of dynamic functional reorganization to the opposite hemisphere that is reversible when normal blood flow is restored. These findings are important to our understanding of the clinical consequences of hemodynamic failure and the role of the ipsilateral hemisphere in maintaining normal neurological function. Ann Neurol 2009;65:203,208 [source] Discovery of cyclic spot activity on the G8 giant HD 208472,ASTRONOMISCHE NACHRICHTEN, Issue 8 2010O. Özdarcan Abstract We present and analyze 17 consecutive years of UBVRI time-series photometry of the spotted giant component of the RS CVn binary HD 208472. Our aim is to determine the morphology and the evolution of its starspots by using periodsearch techniques and two-spot light-curve modelling. Spots on HD208472 always occur on hemispheres facing the observer during orbital quadrature and flip their location to the opposite hemisphere every approximately six years. The times when the spots change their preferential hemisphere correspond to times when the light curve amplitudes are the smallest and when abrupt changes of the photometric periods are observed. During these times the star is also close to a relative maximum brightness, suggesting a vanishing overall spottedness at each end of the previous cycle and the start of a new one. We find evidence for a 6.28±0.06-yr brightness cycle, which we interpret to be a stellar analog of the solar 11-year sunspot cycle. We also present clear evidence for a brightening trend, approximated with a 21.5±0.5-yr period, possibly due to a stellar analog of the solar Gleissberg cycle. From the two-spot modelling we also determine an upper limit for the differential-rotation coefficient of , = ,P/P of 0.004±0.010, which would be fifty times weaker than on the Sun (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Bedside biochemical monitoring of the penumbra zone surrounding an evacuated acute subdural haematomaACTA NEUROLOGICA SCANDINAVICA, Issue 3 2003N. Stĺhl We describe a penumbra zone with increased biochemical vulnerability in cerebral cortex underlying an evacuated acute subdural haematoma. Two microdialysis catheters were placed in this zone and one catheter was placed in the opposite, less injured hemisphere. The microdialysis perfusates were analysed bedside for glucose, pyruvate, lactate, glutamate, and glycerol. In the penumbra zone, but not in the opposite hemisphere, energy metabolism was seriously disturbed with signs of cell membrane degradation. During an adverse event (decrease in haemoglobin level, systemic blood pressure and cerebral perfusion pressure) the perturbation of energy metabolism increased in this zone. Energy metabolism recovered and the signs of cell membrane degradation disappeared after normalization of the physiological parameters. We use the term biochemical penumbra zone to describe an area with signs of energy failure and cell membrane degradation, which has a capacity to regain a normal metabolic pattern but also an increased vulnerability to secondary insults. [source] Asymmetric Functional Colloids Through Selective Hemisphere ModificationADVANCED MATERIALS, Issue 16 2005A. Correa-Duarte Core,shell colloids with two well-differentiated sides (see Figure) have been produced by a combination of electron beam evaporation (EBE) and polyelectrolyte-driven layer-by-layer (LbL) assembly. The colloids are patterned with different optical and magnetic functionalities through deposition of silica-coated gold nanoparticles and evaporation of gold and nickel, forming different thin films on opposite hemispheres. [source] Four-colour photometry of EY Dra: A study of an ultra-fast rotating active dM1-2e starASTRONOMISCHE NACHRICHTEN, Issue 3 2010K. Vida Abstract We present more than 1000-day long photometry of EY Draconis in BV (RI)C passbands. The changes in the light curve are caused by the spottedness of the rotating surface. Modelling of the spotted surface shows that there are two large active regions present on the star on the opposite hemispheres. The evolution of the surface patterns suggests a flip-flop phenomenon. Using Fourier analysis, we detect a rotation period of Prot = 0.45875 d, and an activity cycle with P , 350 d, similar to the 11-year long cycle of the Sun. This cycle with its year-long period is the shortest one ever detected on active stars. Two bright flares are also detected and analysed (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Synthesis of trans -1, trans -2, trans -3, and trans -4 Bisadducts of C60 by Regio- and Stereoselective Tether-Directed Remote FunctionalizationCHEMISTRY - A EUROPEAN JOURNAL, Issue 8 2005Sergey Sergeyev Dr. Abstract The double Bingel reaction of fullerene C60 with bismalonates attached to a Tröger base derived tether afforded trans -1, trans -2, trans -3, and trans -4 bisadducts with excellent regioselectivity. In particular, enantiomerically pure bisadducts with inherently chiral trans -2 or trans -3 addition patterns were prepared starting from enantiomerically pure bismalonates. The absolute configuration of the trans -2 and trans -3 bisadducts was established from their CD spectra. The excellent diastereoselectivity in the double additions to give the trans -2 bisadducts is particularly remarkable given the large distance between the two reacting bonds in opposite hemispheres of the fullerene that is spanned by the tether. Now, all inherently chiral double addition patterns are readily available by tether-directed functionalization using appropriate chiral, nonracemic spacers. [source] | ||||||||||