Characterization of boron doped diamond during oxidation processes: Relationship between electronic structure and electrochemical activity

This work investigates the behaviour of BDD samples differently aged by an oxidative treatment. Two series of data are presented: the first in acid solutions was used to derive information about the electronic structure of the samples, whereas measurements in equimolar ferro/ferri cyanide solutions were performed to test the activity of the samples towards charge transfer reaction. Flat band potential as well as energy levels of conduction and valence bands were calculated for new and aged samples. These parameters, together with the current voltage response, are crucial information for a comprehensive interpretation of the behaviour of samples.     

Effect of processing stages of apple juice concentrate on patulin levels

The effects of different stages of apple juice concentrate production on patulin levels were investigated. Patulin was detected in all samples analyzed in concentrations ranging from 56 to 653 μg/L. Apple paste resulted from milling process had high levels of patulin. The results of this study indicate that it is possible to reduce patulin level in apple juices. After pasteurization, enzymatic treatment, microfiltration and evaporation processes, the mean loss of patulin was 39.6, 28.3, 20.1 and 28.4%, respectively. When apple juices concentrate were diluted from 69 to 12°Brix to consume, patulin content ranged from 15 to 46 μg/L. Patulin content in all juice samples was lower than the limit of 50 μg/L considered acceptable by the Codex Alimentarius Commission. But if consider the maximum permitted concentration established for apple products intended for infants and young children by The Commission of the European Communities all samples were found to exceed patulin concentration of 10 μg/L.     

Un linguaggio simbolico di simulazione: Il siford

Simulation has proved to be a powerful tool for research in all problems for which satisfactory analitical techniques are not available. It is well known, for instance, the considerable difficulty of the analytical approach to systems containing a certain number of stochastic variables which interact reciprocally. It is also known that in the intensive use of digital simulation (Monte Carlo Method) the long time required for the compilation and the debugging of the corresponding programmes arises as a principal obstacle to efficient solution. The SIFOR language was created to bypass the above mentioned difficulties. By means of the SIFOR language one has but to describe the system in question through a block diagram (SIFOR blocks). On the bases of such a scheme the SIFOR compiler the supplies requested simulation programme. The aim of this paper is to describe the SIFOR blocks which are to be employed in the programme-write up. Some of the SIFOR blocks «generate» flows of transactions, other ones define the lows with which the transactions «go through» the system, and finally other blocks «absolve» the transactions when the latter have completed their course. During the simulated passage of the transactions through the system the programme holds all the informations which, after appropriate handling, represent the final, results of the simulation.     

采用中间电压总线架构的分布式电源转换

今天,电信、汽车与工业应用对复杂电源系统要求更高的功率效率、多个低电压供电通道,同时更有限的容差和高级顺序上电功能。例如,通信系统的开发者不断在相同尺寸的电路板上装入更多元器件,使其具备更高的性能。电源系统必须供应很低的输出电压与大电流,才能满足高性能通信系统芯片的电源需求。美国国家半导体最近推出一款电源转换系列集成电路(IC),用于中间电源总线的新型控制器,使得用于分布式电源架构的先进隔离直流/直流控制器系列更臻完善,可满足下一代通信系统的电源需求。LM5000系列可耐受高达100V的瞬变电压,比现有解决方案的效率…     

Factor structure of the Anxiety Sensitivity Index among African American college students.

This study examined the factor structure of the Anxiety Sensitivity Index (ASI) among African American college students. Confirmatory factor analysis indicated the 3-factor solution commonly found among other populations did not fit the data for African Americans. Although an exploratory factor analysis indicated the presence of a Mental Incapacitation factor, the Physical Concerns factor was divided into unsteady and cardiovascular concerns. Items typically comprising the Social factor were reflective of emotional controllability among African Americans. The ASI was also moderately correlated with measures of anxiety and depression providing only weak evidence of convergent and discriminate validity of the ASI for African Americans. Although support for the multidimensional nature of AS was found, the factor composition differs for African Americans. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Accessing the influence of repositioning on the pelvis' 3-D orientation in wheelchair users.

This study aimed at evaluating the effects of mechanical repositioning, obtained by the increase in seat-to-back (STB) and system tilt angles, on the position of the pelvis with spinal-cord injured subjects seated in a wheelchair. The noninvasive method used combined magnetic resonance imaging (MRI) images of the whole pelvis obtained in a supine posture and ultrasound images of the pelvic iliac crests obtained in four seating positions. The matching of the two image data sets enabled the location of fourteen pelvic landmarks in the seated positions. From these landmarks, the pelvic tilt, obliquity, and transverse rotation, and the three-dimensional (3-D) motion of the pelvis were calculated. Results showed that the increase in STB angle is not equal to the calculated increase in pelvic tilt and that the pelvis rotated posteriorly, moved forward and downwards. An increase in the system tilt moved the pelvis rearwards and downwards, which counter-balanced the movement seen with the increase in STB. At the return to the first position, no significant changes were observed in the pelvis' position and orientation compared to the initial posture. Results also demonstrated the importance in calculating the total 3-D rotations and translations to characterize adequately the pelvic movement.     

用LM3488设计回扫开关电源供应器

回扫拓朴结构是设计多输出分离开关电源及48伏输入电信应用方案最常用的拓朴结构。下文介绍如何利用高效率的LM3488低边N通道电流模式控制器设计成本低廉的断续式回扫开关稳压器。 回扫转换器基本上是一种降压/升压转换器。 图1-a所示的单式电感器可以分为两个并行连接的电感器,其线圈匝数为1:1(图1-b)。分开之后,电感器的基本功能不会改变,而同一核心的两个并行线圈相等于一个线圈。如果两个线圈之间     

Molecular analysis of poliovirus 3 isolated from an aerosol generated by a waste water treatment plant

We examined three samples of lysates from cell cultures that had previously been infected by the aerosol generated by a waste water treatment plant near Pisa. We first attempted to confirm that we were dealing with one of the enterovirus family, using an inverse PCR analysis of the RNA extracted from the cell lysates. This identified a single genome sequences in all the samples, which corresponded to poliovirus 3. Sequence analyses revealed that the genotyping of poliovirus 3 was accurate for the species, irrespective of the genomic region sequenced. Subspecies genotyping is only possible for the translated region, and in this case, it identified the Poliovirus type 3 Leon 12a1b strain as ancestor of the virus isolated. Molecular analyses were then carried out on the wild virus in the regions VP2 (9623 bp), VP3 (922 bp) and VP1 (1128 bp) and found various nucleotide mutations (e.g. 472_T→C; 970_{G→C, Cys→Ser}; 1319_{G→T, Val→Leu}; 1743_{T→C, Val→Ala}; 1817_{C→T, Hys→Tyr}). Thermosensitivity tests at 34°C and 44°C showed a slight reversion to the heat resistant phenotype. The need for adequate protective measures for plant staff, together with the frequent use of treated water for irrigation, means that effective methods of aerosol borne pathogen detection and risk determination must be adopted.     

Effects of low pressure and a rectification column on the volatile composition of fermented grape distillate

Fermented crushed Prosecco grapes were distilled using a batch still under normal (100.9 kPa) and reduced pressure (40 or 47 kPa) with and without the rectifying column of the distillation equipment. To improve insight into the behaviour of ethanol and the partitioning of some volatile compounds, each distillate was collected in fractions and analysed for lower volatile alcohols and esters. The results show that the behaviour of ethanol under reduced pressure was more consistent, the proof level higher than at normal pressure and there was a stripping effect on the volatile compounds considered at low pressure. This effect is enhanced when the rectifying column is included. It was concluded that it could be advantageous to use 'vacuum distillation' because it simplifies the operation of the equipment and leads to an overall reduction of the heating required, although there are problems of losses of desirable aromatic compounds.