ABSTRACT
BACKGROUND AND PURPOSE
Infarct volume is used as a surrogate outcome measure in clinical trials of therapies for acute ischemic stroke. ABC/2 is a fast volumetric method, but its accuracy ...remains to be determined. We aimed to study the accuracy and reproducibility of ABC/2 in determining acute infarct volume with diffusion‐weighted imaging.
METHODS
We studied 86 consecutive patients with acute ischemic stroke. Three blinded observers determined volume with the ABC/2 method, and the results were compared with those of the manual planimetric method.
RESULTS
The ABC/2 technique overestimated infarct volume by a median false increase (variable ABC/2 volume minus planimetric volume) of 7.33 cm3 (1.29, 22.170, representing a 162.56% increase over the value of the gold standard (variable ABC/2 volume over planimetric volume) (121.70, 248.52). In each method, the interrater reliability was excellent: the intraclass correlations were .992 and .985 for the ABC/2 technique and planimetric method, respectively.
CONCLUSIONS
ABC/2 is volumetric method with clinical value but it consistently overestimates the real infarct volume. J Neuroimaging 2012;22:155‐159
Self-focusing, also known as Talbot's effect had been widely studied by the scientific community. In this paper we show self-focusing as a coherence propagation phenomenon, in particular we studied ...self-focusing for a pulse propagating in a metamaterial with both behaviors: left handed material (LHM) and right handed material (RHM). These dual behaviors allow the construction of frequency filters in the range of frequency in which the metamaterial stops behaving as a LHM (negative refraction index) and begins an RHM behavior (positive refraction index). The coherence length (CL) for pulses propagating in these metamaterials seems to be larger when its frequencies are in the LHM region. Finally, we show that the cell's size turns out to be critical in designing the filter, and as an example we present here four metamaterial cells.
Retinopathy of prematurity (ROP) is one of the leading causes of preventable blindness in children worldwide. Middle-income nations are currently experiencing epidemic levels of ROP, because greater ...access to neonatal intensive care units has improved survival rates of premature infants, but without sophisticated oxygen regulation. The epidemiology, screening infrastructure, treatment options, and challenges that these countries face are often tied to unique local socioeconomic, cultural, geopolitical, and medical factors. We present an overview and narratives of the current state of ROP in eight countries that are or soon will be experiencing ROP epidemics-India, Kenya, Mexico, Nigeria, Phillipines, Romania, Thailand, and Venezuela-with a view to fostering both an understanding of the differences in the ROP landscape in various settings and an interest in the further development of ROP screening and treatment services tailored to local requirements.
When food is restricted to a few hours daily, animals increase their locomotor activity 2-3 h before food access, which has been termed food anticipatory activity. Food entrainment has been linked to ...the expression of a circadian food-entrained oscillator (FEO) and the anatomic substrate of this oscillator seems to depend on diverse neural systems and peripheral organs. Previously, we have described a differential involvement of hypothalamic nuclei in the food-entrained process. For the food entrainment pathway, the communication between the gastrointestinal system and central nervous system is essential. The visceral synaptic input to the brain stem arrives at the dorsal vagal complex and is transmitted directly from the nucleus of the solitary tract (NST) or via the parabrachial nucleus (PBN) to hypothalamic nuclei and other areas of the forebrain. The present study aims to characterize the response of brain stem structures in food entrainment. The expression of c-Fos immunoreactivity (c-Fos-IR) was used to identify neuronal activation. Present data show an increased c-Fos-IR following meal time in all brain stem nuclei studied. Food-entrained temporal patterns did not persist under fasting conditions, indicating a direct dependence on feeding-elicited signals for this activation. Because NST and PBN exhibited a different and increased response from that expected after a regular meal, we suggest that food entrainment promotes ingestive adaptations that lead to a modified activation in these brain stem nuclei, e.g., stomach distension. Neural information provided by these nuclei to the brain may provide the essential entraining signal for FEO.
Candida albicans produces large amounts of the pentitol D-arabitol in culture and in infected mammalian hosts, but the functional and pathogenic significance of D-arabitol in C. albicans is not ...known. In this study, we sought to elucidate the pathway by which C. albicans synthesizes D-arabitol and to identify and characterize key enzymes in this pathway. C. albicans B311 produced D-14C-1arabitol from 14C-2glucose; this finding implies on structural grounds that D-ribulose-5-PO4 from the pentose pathway is the major metabolic precursor of D-arabitol. NAD- or NADP-dependent pentitol dehydrogenases catalyze the final steps in D-arabitol biosynthesis in other fungi; therefore, lysates of C. albicans B311 were tested for enzymes of this class and were found to contain a previously unknown NAD-dependent D-arabitol dehydrogenase (ArDH). The ArDH structural gene was cloned by constructing a new D-arabitol utilization pathway in Escherichia coli. The C. albicans ArDH gene expressed in E. coli and Saccharomyces cerevisiae an enzyme that catalyzes the reaction D-arabitol + NAD reversible reaction with D-ribulose + NADH; this gene was present as a single copy per haploid genome, and its deduced peptide sequence was homologous with sequences of several members of the short-chain dehydrogenase family of enzymes. These results suggest that (i) C. albicans synthesizes D-arabitol by dephosphorylating and reducing the pentose pathway intermediate D-ribulose-5-PO4 and (ii) ArDH catalyzes the final step in this pathway
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