Influence of synthesis conditions on carbonate entrapment in perovskite SrSnO3

Strontium stannate (SrSnO₃), a perovskite material, was synthesized by the polymeric precursor method, with different routes to eliminate organic matter. The utilization of pure oxygen for the elimination of organic matter changed the Raman spectra, especially in the low frequency region. Some peaks, which were previously assigned to the perovskite phase, were not noticed when the carbonate amount was lower. On the other hand, the profile of the IR spectra and XRD patterns did not change. These results suggest that carbonate may be present inside the perovskite lattice.     

Hancornia speciosa latex for biomedical applications: physical and chemical properties,biocompatibility assessment and angiogenic activity

The latex obtained from Hancornia speciosa is used in folk medicine for treatment of several diseases, such as acne, warts, diabetes, gastritis and inflammation. In this work, we describe the biocompatibility assessment and angiogenic properties of H. speciosa latex and its potential application in medicine. The physical–chemical characterization was carried out following different methodologies (CHN elemental analyses; thermogravimetric analyses and Fourier transform infrared spectroscopy). The biocompatibility was evaluated through cytotoxicity and genotoxicity tests in fibroblast mouse cells and the angiogenic properties were evaluated using the chick chorioallantoic membrane (CAM) assay model. The physical–chemical results showed that the structure of Hancornia speciosa latex biomembrane is very similar to that of Hevea brasiliensis (commercially available product). Moreover, the cytotoxicity and genotoxicity assays showed that H. speciosa latex is biocompatible with life systems and can be a good biomaterial for medical applications. The CAM test showed the efficient ability of H. speciosa latex in neovascularization of tissues. The histological analysis was in accordance with the results obtained in the CAM assay. Our data indicate that the latex obtained from H. speciosa and eluted in water showed significant angiogenic activity without any cytotoxic or genotoxic effects on life systems. The same did not occur with H. speciosa latex stabilized with ammonia. Addition of ammonia does not have significant effects on the structure of biomembranes, but showed a smaller cell survival and a significant genotoxicity effect. This study contributes to the understanding of the potentialities of H. speciosa latex as a source of new phytomedicines.     

Can Brazil replace 5% of the 2025 gasoline world demand with ethanol?

Increasing use of petroleum, coupled with concern for global warming, demands the development and institution of CO₂ reducing, non-fossil fuel-based alternative energy-generating strategies. Ethanol is a potential alternative, particularly when produced in a sustainable way as is envisioned for sugarcane in Brazil. We consider the expansion of sugarcane-derived ethanol to displace 5% of projected gasoline use worldwide in 2025. With existing technology, 21 million hectares of land will be required to produce the necessary ethanol. This is less than 7% of current Brazilian agricultural land and equivalent to current soybean land use. New production lands come from pasture made available through improving pasture management in the cattle industry. With the continued introduction of new cane varieties (annual yield increases of about 1.6%) and new ethanol production technologies, namely the hydrolysis of bagasse to sugars for ethanol production and sugarcane trash collection providing renewable process energy production, this could reduce these modest land requirements by 29–38%.     

Thermal analysis in coated cutting tools

This work studies the heat influence in cutting tools considering the variation of the coating thickness and the heat flux. K10 and diamond tools substrate with TiN and Al₂O₃ coatings were used. The numerical methodology utilizes the ANSYS^® CFX software. Boundary conditions and constant thermo physical properties of the solids involved in the numerical analysis are known. To validate the proposed methodology an experiment is used. The TiN and Al₂O₃ coatings did not show satisfying results during a continuous cutting process. It showed a slight reduction in the heat flux for the 10 (µm) TiN and Al₂O₃ coatings.     

Study of strengthening solutions for glued-laminated wood beams of maritime pine wood

The application of the concept of glued-laminated wood (glulam) to improve the mechanical properties of the solid wood of the maritime pine (Pinus pinaster) is the subject of this work. Two reinforced glued-laminated wood beams are proposed and assessed. The first is based on a concept of laminated wood composite with fiber glass; the second is based on the application of pultruded lamellas glued to the most stressed tensile region of the glued-laminated beams. In order to demonstrate the potential of the proposed strengthening solutions, a comparison between their mechanical behaviors and the mechanical behaviors of the conventional glued-laminated and solid beams are performed. Static load–deflection curves, an equivalent Young’s modulus, the ultimate strain and modulus of rupture are determined using 3-point quasi-static bending tests. In general, it is demonstrated the beneficial effect of the proposed strengthening solutions both in terms of resistance and ductility.     

A low-cost neurostimulator with accurate pulsed-current control

A constant-current stimulator for high-impedance loads using only low-cost standard high-voltage components is presented. A voltage-regulator powers an oscillator built across the primary of a step-up transformer whose secondary supplies, after rectification, the high voltage to a switched current-mirror in the driving stage. Adjusting the regulated voltage controls the pulsed-current intensity. A prototype produces stimulus of amplitude and pulsewidth within 0 < or = I(skin) < or = 20 mA and 50 micros < or = T(pulse) < or = 1 ms, respectively. Pulse-repetition spans from 1 Hz to 10 Hz. Worst case ripple is 3.7% at I(skin) = 1 mA. Overall consumption is 5.6 W at I(skin) = 20 mA.     

The road to RoboCup 2050

The ultimate goal of the RoboCup initiative is stated as follows: by mid-21st century, a team of fully autonomous humanoid robot soccer players shall win the soccer game, comply with the official rule of the FIFA, against the winner of the most recent World Cup. The authors consider this goal from the perspective of how close we are to it and what has to be done to reach it     

A long follow-up on prostate specific antigen density and prostate biopsy

OBJECTIVE: To determine prostate specific antigen density (PSAD) in a risk population without evidence of prostatic cancer, and to assess the long-term usefulness of PSAD as a parameter for determining the need for a prostatic biopsy in patients with a normal digital rectal examination (DRE) and transrectal ultrasound (TRUS). METHODS: The records of 582 patients referred to the clinic between February, 1992 and February, 1994 were studied retrospectively. All these patients with lower urinary tract symptoms (LUTS) were evaluated based on the following parameters: digital rectal examination, serum PSA levels, prostate volume measured using transrectal ultrasound and PSAD. Prostatic biopsy was performed on 431 patients who had a serum PSA level greater than 4.0 ng/mL. A total of 299 patients (69.3%) had PSA levels between 4.0 and 10.0 ng/mL and represented the target population. The study had two parts, in the first one cancer was diagnosed just by one biopsy and in part II, the patients with negative biopsy in part I were followed for a two-year period and required 2 or 3 biopsies for diagnosis. Of the total of patients who had a negative prostate biopsy in part I of the study, 269 were followed for a period of two years with repeated prostate biopsies. RESULTS: Overall prostate cancer was detected in 22/299 (13.9%) patients, 6/105 (5.7%) with PSAD up to 0.15 and 16/194 (8.2%) with PSAD over 0.15 (p = 0.569). CONCLUSION: PSAD is a useful indicator in decreasing the number of negative biopsies in patients with benign prostatic hyperplasia. However, in a long-term follow-up the PSAD (cutoff level 0.15) was unable to predict which patients had a positive biopsy. According to our results, 5.6% of patients with prostate cancer will be missed using the PSAD criteria.