54 resultados para DER-WAALS INTERACTION
Resumo:
Continuous growth in the number of immigrant students has changed the Finnish school environment. The resulting multicultural school environment is new for both teachers and students. In order to develop multicultural learning environments, there is a need to understand immigrant students everyday lives in school. In this study, home economics is seen as a fruitful school subject area for understanding these immigrant students lives as they cope with school and home cultures that may be very different from each other. Home economics includes a great deal of knowledge and skills that immigrant students need during their everyday activities outside of school. -- The main aim of the study is to clarify the characteristics of multicultural home economics classroom practices and the multicultural contacts and interaction that take place between the students and the teacher. The study includes four parts. The first part, an ethnographical prestudy, aims to understand the challenges of multicultural schoolwork with the aid of ethnographical fieldwork done in one multicultural school. The second part outlines the theoretical frames of the study and focuses on the sociocultural approach. The third part of the study presents an analysis of videodata collected in a multicultural home economics classroom. The teacher s and students interaction in the home economics classroom is analyzed through the concepts of the sociocultural approach and the cultural-historical activity theory. Firstly, this is done by analyzing the focusedness of the teacher s and the students actions as well as the questions presented and apparent disturbances during classroom interaction. Secondly, the immigrant students everyday experiences and cultural background are examined as they appear during discussions in the home economics lessons. Thirdly, the teacher s tool-use and actions as a human mediator are clarified during interaction in the classroom. The fourth part presents the results, according to which a practice-based approach in the multicultural classroom situation is a prerequisite for the teacher s and the students shared object during classroom interaction. Also, the practice-based approach facilitates students understanding during teaching and learning situations. Practice in this study is understood as collaborative teaching and learning situations that include 1) guided activating learning, 2) establishing connections with students everyday lives and 3) multiple tool-use. Guided activating learning in the classroom is defined as situations that occur and assignments that are done with a knowledgeable adult or peer and include action. The teacher s demonstrations during the practical part of the lessons seemed to be fruitful in the teaching and learning situations in the multicultural classroom. Establishing connections with students everyday lives motivated students to follow the lesson and supported understanding of meaning. Furthermore, if multiple tools (both psychological and material) were used, the students managed better with new and sometimes difficult concepts and different working habits, and accomplished the practical work more smoothly . The teacher s tool-use and role as a mediator of meaning are also highlighted in the data analysis. Hopefully, this study can provide a seedbed for situations in which knowledge produced together, as well as horizontally oriented tool-use, can make school-learned knowledge more relevant to immigrant students everyday lives, and help students to better cope with both classroom work and outside activities. KEY WORDS: home economics education, multicultural education, sociocultural perspective, classroom interaction, videoanalysis
Resumo:
Background: The Ewing sarcoma family of tumors (ESFT) are rare but highly malignant neoplasms that occur mainly in bone or but also in soft tissue. ESFT affects patients typically in their second decade of life, whereby children and adolescents bear the heaviest incidence burden. Despite recent advances in the clinical management of ESFT patients, their prognosis and survival are still disappointingly poor, especially in cases with metastasis. No targeted therapy for ESFT patients is currently available. Moreover, based merely on current clinical and biological characteristics, accurate classification of ESFT patients often fails at the time of diagnosis. Therefore, there is a constant need for novel molecular biomarkers to be applied in tandem with conventional parameters to further intensify ESFT risk-stratification and treatment selection, and ultimately to develop novel targeted therapies. In this context, a greater understanding of the genetics and immune characteristics of ESFT is needed. Aims: This study sought to open novel insights into gene copy number changes and gene expression in ESFT and, further, to enlighten the role of inflammation in ESFT. For this purpose, microarrays were used to provide gene-level information on a genomewide scale. In addition, this study focused on screening of 9p21.3 deletion sizes and frequencies in ESFT and, in another pediatric cancer, acute lymphocytic leukemia (ALL), in order to define more exact criteria for highrisk patient selection and to provide data for developing a more reliable diagnostic method to detect CDKN2A deletions. Results: In study I, 20 novel ESFT-associated suppressor genes and oncogenes were pinpointed using combined array CGH and expression analysis. In addition, interesting chromosomal rearrangements were identified: (1) Duplication of derivative chromosome der(22)(11;22) was detected in three ESFT patients. This duplication included the EWSR1-FLI1 fusion gene leading to increase in its copy number; (2) Cryptic amplifications on chromosomes 20 and 22 were detected, suggesting a novel translocation between chromosomes 20 and 22, which most probably produces a fusion between EWSR1 and NFATC2. In study II, bioinformatic analysis of ESFT expression profiles showed that inflammatory gene activation is detectable in ESFT patient samples and that the activation is characterized by macrophage gene expression. Most interestingly, ESFT patient samples were shown to express certain inflammatory genes that were prognostically significant. High local expression of C5 and JAK1 at the tumor site was shown to associate with favorable clinical outcome, whereas high local expression of IL8 was shown to be detrimental. Studies III and IV showed that the smallest overlapping region of deletion in 9p21.3 includes CDKN2A in all cases and that the length of this region is 12.2 kb in both Ewing sarcoma and ALL. Furthermore, our results showed that the most widely used commercial CDKN2A FISH probe creates false negative results in the narrowest microdeletion cases (<190 kb). Therefore, more accurate methods should be developed for the detection of deletions in the CDKN2A locus. Conclusions: This study provides novel insights into the genetic changes involved in the biology of ESFT, in the interaction between ESFT cells and immune system, and in the inactivation of CDKN2A. Novel ESFT biomarker genes identified in this study serve as a useful resource for future studies and in developing novel therapeutic strategies to improve the survival of patients with ESFT.
Resumo:
The sustainability of food production has increasingly attracted the attention of consumers, farmers, food and retailing companies, and politicians. One manifestation of such attention is the growing interest in organic foods. Organic agriculture has the potential to enhance the ecological modernisation of food production by implementing the organic method as a preventative innovation that simultaneously produces environmental and economic benefits. However, in addition to the challenges to organic farming, the small market share of organic products in many countries today and Finland in particular risks undermining the achievement of such benefits. The problems identified as hindrances to the increased consumption of organic food are the poor availability, limited variety and high prices of organic products, the complicated buying decisions and the difficulties in delivering the intangible value of organic foods. Small volumes and sporadic markets, high costs, lack of market information, as well as poor supply reliability are obstacles to increasing the volume of organic production and processing. These problems shift the focus from a single actor to the entire supply chain and require solutions that involve more interaction among the actors within the organic chain. As an entity, the organic food chain has received very little scholarly attention. Researchers have mainly approached the organic chain from the perspective of a single actor, or they have described its structure rather than the interaction between the actors. Consequently, interaction among the primary actors in organic chains, i.e. farmers, manufacturers, retailers and consumers, has largely gone unexamined. The purpose of this study is to shed light on the interaction of the primary actors within a whole organic chain in relation to the ecological modernisation of food production. This information is organised into a conceptual framework to help illuminate this complex field. This thesis integrates the theories and concepts of three approaches: food system studies, supply chain management and ecological modernisation. Through a case study, a conceptual system framework will be developed and applied to a real life-situation. The thesis is supported by research published in four articles. All examine the same organic chains through case studies, but each approaches the problem from a different, complementary perspective. The findings indicated that regardless of the coherent values emphasising responsibility, the organic chains were loosely integrated to operate as a system. The focus was on product flow, leaving other aspects of value creation largely aside. Communication with consumers was rare, and none of the actors had taken a leading role in enhancing the market for organic products. Such a situation presents unsuitable conditions for ecological modernisation of food production through organic food and calls for contributions from stakeholders other than those directly involved in the product chain. The findings inspired a revision of the original conceptual framework. The revised framework, the three-layer framework , distinguishes the different layers of interaction. By gradually enlarging the chain orientation the different but interrelated layers become visible. A framework is thus provided for further research and for understanding practical implications of the performance of organic food chains. The revised framework provides both an ideal model for organic chains in relation to ecological modernisation and demonstrates a situation consistent with the empirical evidence.
Resumo:
This doctoral thesis describes the development of a miniaturized capillary electrochromatography (CEC) technique suitable for the study of interactions between various nanodomains of biological importance. The particular focus of the study was low-density lipoprotein (LDL) particles and their interaction with components of the extracellular matrix (ECM). LDL transports cholesterol to the tissues through the blood circulation, but when the LDL level becomes too high the particles begin to permeate and accumulate in the arteries. Through binding sites on apolipoprotein B-100 (apoB-100), LDL interacts with components of the ECM, such as proteoglycans (PGs) and collagen, in what is considered the key mechanism in the retention of lipoproteins and onset of atherosclerosis. Hydrolytic enzymes and oxidizing agents in the ECM may later successively degrade the LDL surface. Metabolic diseases such as diabetes may provoke damage of the ECM structure through the non-enzymatic reaction of glucose with collagen. In this work, fused silica capillaries of 50 micrometer i.d. were successfully coated with LDL and collagen, and steroids and apoB-100 peptide fragments were introduced as model compounds for interaction studies. The LDL coating was modified with copper sulphate or hydrolytic enzymes, and the interactions of steroids with the native and oxidized lipoproteins were studied. Lipids were also removed from the LDL particle coating leaving behind an apoB-100 surface for further studies. The development of collagen and collagen decorin coatings was helpful in the elucidation of the interactions of apoB-100 peptide fragments with the primary ECM component, collagen. Furthermore, the collagen I coating provided a good platform for glycation studies and for clarification of LDL interactions with native and modified collagen. All methods developed are inexpensive, requiring just small amounts of biomaterial. Moreover, the experimental conditions in CEC are easily modified, and the analyses can be carried out in a reasonable time frame. Other techniques were employed to support and complement the CEC studies. Scanning electron microscopy and atomic force microscopy provided crucial visual information about the native and modified coatings. Asymmetrical flow field-flow fractionation enabled size measurements of the modified lipoproteins. Finally, the CEC results were exploited to develop new sensor chips for a continuous flow quartz crystal microbalance technique, which provided complementary information about LDL ECM interactions. This thesis demonstrates the potential of CEC as a valuable and flexible technique for surface interaction studies. Further, CEC can serve as a novel microreactor for the in situ modification of LDL and collagen coatings. The coatings developed in this study provide useful platforms for a diversity of future investigations on biological nanodomains.
Resumo:
The purpose of this study is to examine the reception of Matthew 5 in Martin Luther s sermons; in other words to investigate how Luther interprets and applies Jesus teaching of the better righteousness and the law in Mt 5. The study applies the reception-historical approach and contributes to the history of effects and the history of interpretation in New Testament exegesis. The study shows that Luther understands the better righteousness of Mt 5 as good works and fulfillment of the law. Luther s interpretation coheres with the intention of the Evangelist, even if Luther s overall concept of righteousness is foreign to Matthew. In Luther s view righteousness is twofold: The greater righteousness of Mt 5 is the second and the actual righteousness (iustitia activa), which follows the first and the foreign righteousness (iustitia passiva). The first righteousness (faith) is for Luther the work of God, while the second righteousness (good works) is co-operation between a Christian and God. In this co-operation the law, as it is taught by Jesus, is not the opposite of the gospel, but the gospel itself in the sense of Christ as an example . The task of the law is to show the dependence of a Christian on God and to help one to love and to serve one s neighbour (brothers as well as enemies) properly. The study underlines a feature in Luther s thinking that has received little attention in Lutheran theology: Luther insists on preaching the law to Christians. In his view Mt 5 is directed to all Christians and particularly to pastors, for whom Jesus here gives an example of how to preach the law. Luther believes similarly to Matthew that Jesus reveals the real meaning of Mosaic Law and confirms its validity for Christians in Mt 5. Like Matthew, Luther insists on the practicability of the commandments of Mt 5 in his view Christians fulfil the law also with joy yet his interpretation of Mt 5 attenuates the radical nature of its commandments. Luther s reception of the individual pericopes of Mt 5 is considerably generative and occasionally contradictory, which is explained by the following factors, among others: Luther receives many ideas from tradition and reads them and his own theological concepts into Matthew s Gospel. He interprets Mt 5 through his understanding of some Old Testament passages as well as Paul. Most of all, Luther s reception of Mt 5 is shaped by his own experience as a preacher, by his relation to his religious enemies, rulers and to the congregation of Wittenberg. Here Luther shares with Matthew the experience of being opposed and concern about the upright living of the believers, which in both cases also explains the polemical tone of the paraenesis.
Resumo:
Productivity is predicted to drive the ecological and evolutionary dynamics of predator-prey interaction through changes in resource allocation between different traits. However, resources are seldom constantly available and thus temporal variation in productivity could have considerable effect on the species' potential to evolve. To study this, three long-term microbial laboratory experiments were established where Serratia marcescens prey bacteria was exposed to predation of protist Tetrahymena thermophila in different prey resource environments. The consequences of prey resource availability for the ecological properties of the predator-prey system, such as trophic dynamics, stability, and virulence, were determined. The evolutionary changes in species traits and prey genetic diversity were measured. The prey defence evolved stronger in high productivity environment. Increased allocation to defence incurred cost in terms of reduced prey resource use ability, which probably constrained prey evolution by increasing the effect of resource competition. However, the magnitude of this trade-off diminished when measured in high resource concentrations. Predation selected for white, non-pigmented, highly defensive prey clones that produced predation resistant biofilm. The biofilm defence was also potentially accompanied with cytotoxicity for predators and could have been traded off with high motility. Evidence for the evolution of predators was also found in one experiment suggesting that co-evolutionary dynamics could affect the evolution and ecology of predator-prey interaction. Temporal variation in resource availability increased variation in predator densities leading to temporally fluctuating selection for prey defences and resource use ability. Temporal variation in resource availability was also able to constrain prey evolution when the allocation to defence incurred high cost. However, when the magnitude of prey trade-off was small and the resource turnover was periodically high, temporal variation facilitated the formation of predator resistant biofilm. The evolution of prey defence constrained the transfer of energy from basal to higher trophic levels, decreasing the strength of top-down regulation on prey community. Predation and temporal variation in productivity decreased the stability of populations and prey traits in general. However, predation-induced destabilization was less pronounced in the high productivity environment where the evolution of prey defence was stronger. In addition, evolution of prey defence weakened the environmental variation induced destabilization of predator population dynamics. Moreover, protozoan predation decreased the S. marcescens virulence in the insect host moth (Parasemia plantaginis) suggesting that species interactions outside the context of host-pathogen relationship could be important indirect drivers for the evolution of pathogenesis. This thesis demonstrates that rapid evolution can affect various ecological properties of predator-prey interaction. The effect of evolution on the ecological dynamics depended on the productivity of the environment, being most evident in the constant environments with high productivity.