Far Infrared Slab Lensing and Subwavelength Imaging in Crystal Quartz

We examine the possibility of using negative refraction stemming from the phonon response in an anisotropic crystal to create a simple slab lens with plane parallel sides, and show that imaging from such a lens should be possible at room temperature despite the effects of absorption that are inevitably present due to phonon damping. In particular, we consider the case of crystal quartz, a system for which experimental measurements consistent with all-angle negative refraction have already been demonstrated. Furthermore, we investigate the possibility of subwavelength imaging from such materials, and show that it should be possible for certain configurations.Comment: 12 pages, 10 figure

Single standard calibration and data processing in flow injection titration based on concentration gradients

This paper describes use of gradients of concentration generated in flow injection (FI) systems to perform determinations based on points where the concentration of titrant and analyte are at stoichiometric ratio. Two procedures were developed. In one procedure the titrant is injected in a FI manifold and merges with the sample which is continuously pumped towards the detector. In the other procedure the sample is injected and merged with the titrant which is continuously pumped. Both techniques make use of concentration gradients of the sample or titrant generated in FI manifolds that contain a mixing chamber. This gradient is calibrated employing only one standard solution (usually the titrant) in order to convert any detector signal, obtained in the elapsed time after injection, to instantaneous concentration values. The flow system is microcomputer controlled and data are treated to locate points where the concentration of titrant and analyte are at the stoichiometric ratio. These points are found in abrupt changes of the signal × concentration curves obtained in the presence of the reaction. The method has been evaluated for determination of Fe(II) and acetic acid by spectrophotometric and conductimetric detection, respectively. Results show a mean relative standard deviation lower than 1%, an average accuracy of 1% and a high sampling processing capability (40 to 60 samples per hour)

Congenital Destructive Hemispheric Lesions And Epilepsy: Clinical Features And Relevance Of Associated Hippocampal Atrophy.

We studied the clinical, EEG and MRI findings in 19 patients with epilepsy secondary to congenital destructive hemispheric insults. Patients were divided in two groups: 10 with cystic lesions (group 1), and 9 with atrophic lesions (group 2). Seizure and EEG features, as well as developmental sequelae were similar between the two groups, except for the finding that patients of group 2 more commonly presented seizures with more than one semiological type. MRI showed hyperintense T2 signal extending beyond the lesion in almost all patients of both groups, and it was more diffuse in group 2. Associated hippocampal atrophy (HA) was observed in 70% of group 1 patients and 77.7% of group 2, and it was not correlated with duration of epilepsy or seizure frequency. There was a good concordance between HA and electroclinical localization. The high prevalence of associated HA in both groups suggests a common pathogenesis with the more obvious lesion. Our findings indicate that in some of these patients with extensive destructive lesions, there may be a more circumscribed epileptogenic area, particularly in those with cystic lesions and HA, leading to a potential rationale for effective surgical treatment.58990-100

A gene signature of 8 genes could identify the risk of recurrence and progression in Dukes' B colon cancer patients

The benefit of postoperative adjuvant chemotherapy in patients with Dukes' B colorectal cancer is still uncertain and its routine use is not recommended. The five-year relapse rate is approximately 25-40% and the identification of patients at high risk of recurrence would represent an important strategy for the use of adjuvant chemotherapy. We retrospectively analyzed gene expression profiles in frozen tumor specimens from patients with Dukes' B colorectal cancer by using high density oligonucleotide microarrays. Our results show a subset of 48 genes differentially expressed with an associated probability <0.001 in the t-test. Another statistical procedure based on the Fisher criterion resulted in 11 genes able to separate both groups. We selected the 8 genes present in both subsets. The differential expression of five genes (CHD2, RPS5, ZNF148, BRI3 and MGC23401) in colon cancer progression was confirmed by real-time PCR in an independent set of patients of Dukes' B and C stages

Agricultura y armas

Copia digital. Zaragoza : Diputación General de Aragón, 201