Vertical microbubble column–A photonic lab-on-chip for cultivation and online analysis of yeast cell cultures

This paper presents a vertically positioned microfluidic system made of poly(dimethylsiloxane) (PDMS) and glass, which can be applied as a microbubble column (μBC) for biotechnological screening in suspension. In this μBC, microbubbles are produced in a cultivation chamber through an integrated nozzle structure. Thus, homogeneous suspension of biomass is achieved in the cultivation chamber without requiring additional mixing elements. Moreover, blockage due to produced carbon dioxide by the microorganisms—a problem predominant in common, horizontally positioned microbioreactors (MBRs)—is avoided, as the gas bubbles are released by buoyancy at the upper part of the microsystem. The patterned PDMS layer is based on an optimized two-lithographic process. Since the naturally hydrophobic PDMS causes problems for the sufficient production of microbubbles, a method based on polyelectrolyte multilayers is applied in order to allow continuous hydrophilization of the already bonded PDMS-glass-system. The μBC comprises various microelements, including stabilization of temperature, control of continuous bubble formation, and two optical configurations for measurement of optical density with two different sensitivities. In addition, the simple and robust application and handling of the μBC is achieved via a custom-made modular plug-in adapter. To validate the scalability from laboratory scale to microscale, and thus to demonstrate the successful application of the μBC as a screening instrument, a batch cultivation of Saccharomyces cerevisiae is performed in the μBC and compared to shake flask cultivation. Monitoring of the biomass growth in the μBC with the integrated online analytics resulted in a specific growth rate of 0.32 h⁻¹, which is almost identical to the one achieved in the shake flask cultivation (0.31 h⁻¹). Therefore, the validity of the μBC as an alternative screening tool compared to other conventional laboratory scale systems in bioprocess development is proven. In addition, vertically positioned microbioreactors show high potential in comparison to conventional screening tools, since they allow for high density of integrated online analytics and therefore minimize time and cost for screening and guarantee improved control and analysis of cultivation parameters.     

Information and its value to health workers in rural Uganda: a qualitative perspective*

A study was conducted in 1998/99 to investigate the accessibility and use of information by health workers in rural Uganda. Data were collected qualitatively using semi‐structured interviews. As a qualitative study, it focused in‐depth on a relatively small sample of health workers selected purposefully. Different categories of health workers were interviewed. Data were analysed using a grounded theory approach. In this paper, two main categories that emerged from the data will be discussed, namely: value of information and constraints. Information was valuable in clinical work, information dissemination, decision making, administration and detection. Constraints to effective information use included the quality and relevance of the information as well as the difficulties of sometimes putting theory into practice. Finally, the concepts that emerged from the analysis of the use of information pointed directly to the information needs of the health workers studied, which shows that information was valuable in meeting those needs. Some implications of the study and areas for further research are highlighted.     

Typical Didactical Activities in the Greek Early‐Years Science Classroom: Do they promote science learning?

This paper presents an epistemological analysis of typical didactical activities noted in early‐years science lessons, which was carried out in an attempt to diagnose the extent to which the teaching practices adopted by early‐years educators are successful in supporting young children’s understanding in science. The analysis of didactical activities used a framework that allowed us to discover whether they promoted desired connections between theoretical ideas, evidence and the material world. Theoretical ideas, evidence and the material world are entities internal to scientific inquiry and, in educational contexts, connections between them are considered essential in assisting the development of young children’s scientific thinking. The results indicated that in the early‐years science classroom scientific activity was mainly confined to the representational level. Intervention practices into the material world were limited, and were based on collected evidence. No interventions based on ideas were identified in the science lessons. Missing links between evidence and theory and between ideas and the material world suggest that the didactical activities analysed did not promote scientific understanding.     

The interplay between spontaneous writing and underlying linguistic representations

European Journal of Psychology of Education - The paper discusses the importance of incorporating naturalistic data from spontaneous written texts in language acquisition research in general, and...     

Active relatives and health-related physical fitness in European adolescents: The HELENA Study

Abstract High physical fitness in childhood and adolescence is positively associated with favourable health-related outcomes. Our aim was to examine the relationship between relatives' (father, mother, brother, sister, and best friend) physical activity engagement and encouragement on adolescents' physical fitness. Adolescents were part of the HELENA study, a multi-centre study conducted in 10 cities from nine European countries in 2006-2008. Participants were 3288 adolescents (48% boys, 52% girls) aged 12.5-17.5 years with valid data on at least one of the three fitness variables studied: muscular strength (standing long jump), speed/agility (4×10 m shuttle run), and cardiorespiratory fitness (20 m shuttle run). The adolescents reported their relatives' physical activity engagement and encouragement. Analysis of covariance showed that relatives' physical activity engagement (father, mother, brother, and best friend) was positively related to cardiorespiratory fitness (P?相似文献   

An analytical investigation of the painting technique of Italian Renaissance master Lorenzo Lotto

This paper presents the first extensive investigation of the composition of both the organic and inorganic media used by Lorenzo Lotto, one of the outstanding artists of the Italian Renaissance in the early 16th century. By investigating four paintings from The State Hermitage Museum collection (Saint-Petersburg, Russia), new insights into the artist's painting techniques were obtained, which contribute to our understanding of the transition from egg tempera to oil painting techniques that took place in Italian paintings between the 15th to the mid 16th century. Inorganic materials were determined using SEM-EDX and PLM, revealing information on the artist's palette. Of particular note was the powdered colourless glass found in the priming layer of the Madonna delle Grazie, which was most likely used as dryer. Organic materials were analysed in individual paint layers using GC-MS, and revealed a mature use of drying oils as paint binders, skilfully mixed with other organic materials and inorganic driers, to obtain the desired aesthetical and technical qualities of the paint. The study revealed that Lotto used the tempera grassa technique through most of his creative life.     

Developing as a teacher in the fields of science and technology

In universities, development as a teacher may be contradicted with developing as a researcher. Most previous studies have investigated pedagogical development merely as a result of pedagogical training and ignored the dual teacher-researcher identity. This study examines what kind of meaningful experiences are perceived to have triggered and influenced the process of developing as a teacher in the fields of science and technology. The data were gathered by interviewing 10 academics who had participated in a pedagogical training offered by a Finnish technical university between 1999 and 2009. Based on a narrative analysis utilizing dimensions of transformative learning, the results highlight the influence of the working environment and experiences, and imply that teacher development process in the fields of science and technology can be better understood in terms of becoming a teacher, rather than as a continual, conscious development process. The resulting teacher-researcher identity provides a basis for pedagogical development.     

Inclusive education in Spain: how do skills,resources, and supports affect regular education teachers’ perceptions of inclusion?

This study examined regular education teachers’ perceptions of inclusion in elementary and secondary schools in Spain and how these perceptions may differ depending on teaching experience, skills, and the availability of resources and supports. Stratified random sampling procedures were used to draw a representative sample of 336 general education teachers (68 kindergarten, 133 elementary, and 135 secondary teachers) from the province of Alicante. The results indicated the acceptance of the principles of inclusion, although teacher skills, time, material resources, and personal supports for inclusion were deemed insufficient. Kindergarten and elementary teachers showed more positive perceptions of inclusion than secondary education teachers, and so did teachers with more personal supports and material resources than those with less supports and resources. The results are discussed in terms of its implications for practice in order to promote more inclusive classrooms in Spain.