In a medium term scenario hybrid powertrain and Internal Combustion Engine (ICE) downsizing represent the actual trend in vehicle technology to reduce fuel consumption and CO2 emission. Concerning downsizing concept, to maintain a reasonable power level in small engines, the application of turbocharging is mandatory both for spark ignited (SI) and compression ignited (CI) engines. Following this aspect, the possibility to couple an electric drive to the turbocharger (electric turbo compound) to recover the residual energy of the exhaust gases is becoming more and more attractive, as demonstrated by several studies around the world and by the current application in the F1 Championship. The present paper shows the first numerical results of a research program in collaboration between the Universities of Pisa and Genoa. This first study is focused on the evaluation of the benefits resulting from the application of an ETC (Electric Turbo Compound) to a small twin-cylinder SI engine (900 cm3). Starting from the experimental maps of two turbines and one compressor, the complete model of a turbocharged engine was created using the AVL BOOST one-dimension code. The numerical activity then moves to the whole vehicle/powertrain modelling, considering three driving cycles and two different vehicle configurations, in order to verify the effectiveness of the proposed ETC solution. Results show that the adoption of ETC is not advantageous if used for a conventional turbocharger turbine, if the target is to optimize the overall efficiency in one specific operating point of the ICE, like in the case of range-extended electric vehicles. Besides, ETC can slightly improve the average overall efficiency when the ICE must provide variable power output, as in the case of conventional or hybrid vehicles. However, the major benefits coming from ETC are the boost range extension in the lowest engine rotational speed region and a possible reduction of turbo lag, which are key points in parallel-hybrid and especially in conventional vehicles. Concerning the whole vehicle/powertrain simulation, first results show that the ETC does not improve fuel economy of the smaller vehicle, especially when employed in urban cycles. The ETC is much more advantageous in the case of the larger vehicle, particularly when extra-urban roads or motorways are considered
Abstract. p53 wild-type is a tumor suppressor gene involved in DNA gene transcription or DNA repair mechanisms. When damage to DNA is unrepairable, p53 induces programmed cell death (apoptosis). The mutant p53 gene is the most frequent molecular alteration in human cancer, including breast cancer. Here, we analyzed the genetic alterations in p53 oncogene expression in 55 patients with breast cancer at different stages and in 8 normal women. We measured by ELISA assay the serum levels of p53 mutant protein and p53 antibodies. Immunohistochemistry and RT-PCR using specific p53 primers as well as mutation detection by DNA sequencing were also evaluated in breast tumor tissue. Serological p53 antibody analysis detected 0/8 (0%), 0/4 (0%) and 9/55 (16.36%) positive cases in normal women, in patients with benign breast disease and in breast carcinoma, respectively. We found positive p53 mutant in the sera of 0/8 (0.0%) normal women, 0/4 (0%) with benign breast disease and 29/55 (52.72%) with breast carcinoma. Immunohistochemistry evaluation was positive in 29/55 (52.73%) with mammary carcinoma and 0/4 (0%) with benign breast disease. A very good correlation between p53 mutant protein detected in serum and p53 accumulation by immunohistochemistry (83.3% positive in both assays) was found in this study. These data suggest that detection of mutated p53 could be a useful serological marker for diagnostic purposes.
Storing hydrogen is one of the major problems concerning its utilization on board vehicles. Today hydrogen can be compressed and stored at 200 or 350 bar (it is foreseen that in a near future storage pressure will reach 700 bar, according to new expected regulations and using tanks in composite materials) or cryogenically liquefied. An alternative solution is storing hydrogen in the form of ammonia that is liquid at roughly 9 bar at environmental temperature and therefore involves relatively small masses and volumes and requires light and low-cost tanks. Moreover, ammonia contains almost 18% hydrogen by mass and, by volume, liquid ammonia contains 1.7 times as much hydrogen as liquid hydrogen. It is well known that ammonia can be burned directly in I.C. engines, however a combustion promoter is necessary to support combustion especially in the case of high-speed S.I. engines. Among the potential promoters, hydrogen is worthy of note, since it is carbon free and counteracts ammonia combustion characteristics. As a matter of fact, hydrogen has high combustion velocity and wide flammability range, whereas ammonia combustion is characterized by low flame speed, low flame temperature, narrow flammability range, high ignition energy and high self-ignition temperature. The experimental activity shown in this paper is correlated with a project that is focused on a range-extended electric vehicle involving an ammonia-plus-hydrogen I.C. engine and where hydrogen is obtained from ammonia by means of on-board catalytic reforming. Accordingly, the test engine is a 505 cm₃ Lombardini twin-cylinder S.I. engine that is well suited to power the onboard electric generator and the activity is aimed at determining proper air-ammonia-hydrogen mixture compositions at actual operating speeds and loads of the engine connected to the electric generator. Hydrogen and ammonia are separately injected in the gaseous phase. The only mechanical modification of the engine involves the intake manifold, where electro-injectors for hydrogen and for ammonia (conventional ones for CNG application with appropriate modification to inner parts) are added to the original ones for gasoline. The experimental results confirm that it is necessary to add hydrogen to air-ammonia mixture to improve ignition and to increase combustion velocity, with ratios that depend mainly on load and less on engine speed. Brake power is less than with gasoline, due to mixture poor volumetric heating value and to ammonia low flame speed that penalizes engine brake thermal efficiency. The amount of hydrogen needed by the engine is compatible with the flow rate provided by the reformer, except at cold start. The maximum NOx emission is 11.5 g/kWh at half load and 4500 rpm, without catalytic reduction
Abstract. the aim of this study was to compare the sensitivity of the serological level of anti-p53 antibodies in breast cancer patients and to correlate its expression level with patient age, histological stage and grade of tumor differentiation. total p53 protein expression (mutant and wild-type) was also determined in the breast cancer tissues using immunohistochemistry (ihc). the serological levels of mutant p53 expression were found to be age-dependent, reaching the highest level at 50 years of age. Faint or low detection was observed in patients ≤30 years of age. Anti-p53-antibodies were detected in patients ≤40 and ≥61 years of age. The serological levels of mutant p53 protein were highly detected in all stages of breast cancer, including the early stages. however, anti-p53 antibodies reached a high level of detection only in stage iii breast carcinomas. no expression was found in patients with benign breast disease. the detection of p53 mutations was dependent on the grade of tumor differentiation, achieving the highest level in the poorly differentiated breast carcinomas. results from ihc were highly correlated with serological p53 mutational analysis. Our findings indicate that mutant p53 in serum is a promising novel parameter for the evaluation of cellular biology and the prognosis of breast cancer from its early stages using blood samples. anti-p53 antibodies were demonstrated to be less sensitive in this study. it is also possible to use the expression of mutant p53 protein as a molecular marker to differentiate benign breast disease from breast carcinoma prior to surgery.
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