Microwave Annealing of High Dose Al<Superscript>+</Superscript>-implanted 4H-SiC: Towards Device Fabrication

High-purity semi-insulating 8° off-axis 〈0001〉 4H-SiC was implanted with Al⁺ at different doses and energies to obtain a dopant concentration in the range of 5 × 10¹⁹–5 × 10²⁰ cm^?3. A custom-made microwave heating system was employed for post-implantation annealing at 2,000 °C for 30 s. Sheet resistance and Hall-effect measurements were performed in the temperature range of 150–700 K. At room temperature, for the highest Al concentration, a minimum resistivity of 3 × 10^?2 Ω cm was obtained, whereas for the lowest Al concentration, the measured resistivity value was 4 × 10^?1 Ω cm. The onset of impurity band conduction was observed at around room temperature for the samples implanted with Al concentrations ≥3 × 10²⁰ cm^?3. Vertical p ⁺-i-n diodes whose anodes were made by 1.5 × 10²⁰ cm^?3 Al⁺ implantation and 2,000 °C/30 s microwave annealing showed exponential forward current–voltage characteristics with two different ideality factors under low current injection. A crossover point of the temperature coefficient of the diode resistance, from negative to positive values, was observed when the forward current entered the ohmic regime.     

Effect of quality, porosity and density on the compression properties of cork

The compression properties of cork were studied on samples obtained from cork planks of two commercial quality classes (good and poor quality), with densities ranging from 0.12–0.20g?cm^-3 and porosities from 0.5 to 22.0%. The stress-strain curves were characterized by an elastic region up to approximately 5% strain, followed by a large plateau up to 60% strain caused by the progressive buckling of cell walls, and a steep stress increase for higher strains corresponding to cell collapse. The direction of compression was a highly significant factor of variation, with cork showing higher strength for the radial compression. Density influenced compression and cork samples with higher density showed overall larger resistance to compression in the three directions. In the elastic region, an exponential model of Young’s modulus in function of cork density could be adjusted. The effect of porosity on compression was small and the stress-strain curves were similar regardless of the porosity of the samples, although there was a trend toward an overall increase of stress with porosity for higher strains. Porosity was characterised by a high variability in the anatomical features of the lenticular filling material and the presence of collapsed and thick walled lignified cells. The inclusion of a porosity parameter for the modelling of the elastic modulus did not improve the prediction obtained with density-based models. There was no significant difference in the compression properties of cork samples obtained from cork planks of good and poor quality classes.     

Diversity among clinical isolates of Proteus penneri detected by random amplified polymorphic DNA analysis

Previous findings indicate that wheel running can have either an aversive or an appetitive effect. That is, wheel running for 30 min induces conditioned taste aversion (CTA) in rats trained while hungry and thirsty but facilitates feeding in non-deprived rats. In Experiment 1, wheel running was also found to be effective in producing CTA in non-deprived rats. Therefore, Experiment 2 tested whether wheel running produces the aversive and appetitive effects simultaneously. During each of four training trials, two groups of non-deprived rats were given a flavored solution to drink for 10 min. Then those in the wheel group were put in running wheels for 30 min whereas those in the cage group spent 30 min in small cages. Finally, all rats were given a 60-min feeding test. After the first trial, the wheel group drank less flavored solution than the cage group during each of the remaining trials. The wheel group also ate more than the cage group on each feeding test. These results indicate that wheel running produces CTA and facilitates eating at the same time. A role for the mesolimbic dopamine reward system in these effects was considered.     

Lycopene‐derived bioactive retinoic acid receptors/retinoid‐X receptors‐activating metabolites may be relevant for lycopene's anti‐cancer potential

Dietary consumption of tomato products and especially the red tomato pigment lycopene has been associated with lower risk of cancer. New evidence is emerging toward metabolic pathways mediating the anti‐cancer activities of lycopene. In this review, we explore associations between tomatoes and lycopene intake and cancer and relate this to the metabolic activation pathways of lycopene via carotene oxygenases and further carotenoid/retinoid‐metabolizing enzymes to apo‐lycopenoids. Several of these apo‐lycopenoids have already been identified but up to date no direct connection between lycopene metabolism and apo‐lycopenoids mediated receptor activation pathways has been established. Retinoic acid receptors/retinoid‐X receptors activation pathways in particular, may be mediated via lycopene metabolites that are related to retinoic acids. Various studies have shown an association between lower concentration of insulin‐like growth factor‐1 upon lycopene treatment, cancer incidences, and retinoid‐mediated signaling. In this review, we interrelate tomato/lycopene ingestion and cancer incidence, with metabolic activation of lycopene and retinoid‐mediated signaling. The aim is to discuss a potential mechanism to explain lycopene related anti‐cancer activities by modulation of insulin‐like growth factor‐1 concentrations via lycopene metabolite activation of retinoid‐mediated signaling.     

Zinc phthalocyanine/magnetic fluid complex: a promising dual nanostructured system for cancer treatment

In this study we evaluated the photophysical, photochemical properties of the zinc phthalocyanine/ magnetic fluid (ZnPC/MF) complex in liposomal medium. As a result of the present investigation we propose the liposome-encapsulated ZnPC/MF complex as a very promising nanostructured device for cancer treatment. The spectroscopy characterization and the in vitro dark toxicity of both ZnPC and ZnPC/MF complex in Hank's and in liposomal medium are reported. Our findings revealed that the spectroscopic properties of the ZnPC associated or not with MF presented little differences and are very close to what one expects from an ideal photosensitizer compound. Indeed, the ZnPC/MF complex in liposomal medium presented lower dark toxicity compared to the ZnPC/MF complex in Hank's, strongly supporting the use of the former for cancer treatment.