De opleiding Life Sciences & Chemistry in het domein AFL wil aansluiten bij ontwikkelingen in het werkveld en didactisch vernieuwen, gericht op de activering van studenten. Hierbij wordt van een beredeneerde inzet van video veel verwacht, vooral bij de curriculumonderdelen die studenten als lastig ervaren. De onderwijseenheid ‘Basischemie’ (blok 1, jaar 1) wordt gezien als een ‘struikelvak’. Een focusgroep met studenten maakte duidelijk dat niet alleen de stof, maar vooral ook de werkwijze in het hbo verschilt van die in de havo. Daarom is besloten tot een herontwerp van de didactiek. Doel van het onderzoek is samen met de betrokken pionier en docent die dit onderwijsonderdeel verzorgt, een uitwerking met inzet van video’s te genereren en te testen, waarbij de video’s aansluiten bij de hoorcolleges, opdat het ontwerp leidt tot actieve betrokkenheid van studenten bij het onderwijs en een beter begrip van de leerstof. Studenten vinden het logisch om voorafgaand aan een hoorcollege de video’s te bekijken en zijn positief over de gecombineerde aanpak van video’s en hoorcolleges. Het ontwerp heeft het ervaren probleem opgelost: de voorkennis is voorafgaand aan het hoorcollege geactiveerd, de oriëntatie op het hoorcollege vond plaats, en het tijd- en plaatsonafhankelijk leren is versterkt. De docent had in het hoorcollege meer tijd over voor extra verwerkingsopdrachten.
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The aim of this study is to examine the effectiveness of collaborative learning with hints and peer tutoring with hints, and individual learning with hints in chemistry laboratory education in a secondary school. A total of 96 eleventh graders participated in this study. The study has a randomized pre‐test and post‐test design with a delayed post‐test. During the four‐week intervention, students were required to carry out eight lab tasks in total. The students filled in a 17‐item self‐assessment of learning gain questionnaire on the last day. Analyses of students’ learning achievements showed that students in both the collaborative learning and peer tutoring situations outperformed those learning individually with hints. The delayed post‐test, which was administered three months later, revealed that students who had been in the peer tutoring situation outscored those in the collaborative learning situation. Student self‐assessment questionnaires on learning gain provided further details in this regard.
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A number of studies have investigated the possibility of extending Electric Vehicle (EV) Lithium-ion battery life by deliberately choosing to store the battery at a low to moderate state of charge. Recently, there has been considerable interest shown in the scheme of a deliberate discharge and subsequent recharge of a battery to yield an overall reduction in battery degradation whilst carrying out Vehicle-to-Grid (V2G) services (so-called `beneficial V2G'). This paper presents an investigation of the conditions permitting successful operation of this method by examining incremental time variation of the relevant parameters for two types of cells from results of the same physical size and chemistry, and similar capacity. These two types of cells are found in this present analysis to offer differing degrees of suitability for beneficial V2G.
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The Green Biotechnology research group focusses on the application of molecular breeding/biotechnological tools and also on the development/analysis of new tools, for the breeding of enhanced vegetable crops and ornamental plants. The research group is positioned within Inholland University of Applied Sciences, Life Sciences & Chemistry and serves as a link between the breeding companies and our education of the skilled technicians of tomorrow. We are working on the development of a method for targeted mutagenesis of plant genomes using the bacterial CRISPR-Cas system. This method greatly enhances the effectiveness and speed by which new crops and plants can be developed
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In de openbare les van mijn collega lector Raymond Pieters, is het domein van het lectoraat ‘Innovative Testing in Life Sciences & Chemistry’ toegelicht. Kort samengevat richt dit lectoraat zich op de ontwikkeling en toepassing van innovatieve teststrategieën om geneesmiddelen, voedingsmiddelen of chemicaliën (stoffen) te beoordelen op hun werkzaamheid (effectiviteit) en veiligheid. De nadruk ligt op de ontwikkeling van snelle, kosteneffectieve testmethoden die een relevante voorspelling van effecten op de gezondheid van de mens en het milieu opleveren én waarbij geen of minder proefdieren worden gebruikt. In mijn les zal ik u laten zien waar proefdieren voor gebruikt worden. Hierbij zal ik mij voornamelijk richten op de Nederlandse situatie. Ik zal ingaan op de wetenschappelijke en maatschappelijke wens om minder proefdieren te gebruiken en op de vraag wat we verstaan onder ‘alternatieven voor dierproeven’. Daarna zal ik bespreken waarom er in Nederland en Europa recentelijk meer aandacht is voor dit onderwerp. Het overzicht zal niet uitputtend zijn, maar zal u een goede indruk geven van het landschap. Ook zal ik stil staan bij de vraag: Waarom zijn we tot nog toe zo weinig succesvol geweest op het gebied van alternatieven voor dierproeven? Wat zijn de obstakels en wat kunnen we hier van leren? Hoe zouden we in de praktijk de toepassing van alternatieven kunnen stimuleren? Wat moet er beter, en hoe gaan we dat doen? Als we slimmer willen testen moeten we de huidige grenzen verleggen, of beter over de grenzen van ons vakgebied heen kijken. Ik zal aangeven waar prioriteiten liggen en hoe we de meeste ‘winst’ kunnen behalen in termen van proefdiervermindering in relatie tot productinnovatie. Tot slot zal ik aangeven welke bruggen we moeten bouwen en wat de rol is van de Hogeschool Utrecht
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Recent and ongoing curriculum innovations in Dutch secondary chemistry education have led to questions about which concepts should be central in the programme and which contexts should be used to embed these concepts into. Another important question is in the discussions about these innovations is: how do students learn chemistry? This thesis examines the relations between students' metacognitive beliefs, their learning outcomes, and the learning activities they conduct in the domain of chemistry. In studying these relations, a useful framework is provided bij Novak's educational theory on 'meaningful learning' as is described in chapter 2. In chapter 3, the development of an instrument for assessing students' metacognitive beliefs regarding chemistry is described. More specifically, this instrument, a questionnaire, consists of items that can be used to determine the nature of students' epistemological beliefs, learning conceptions, and goal orientations concerning chemistry. Using this instrument, it was found that the students' aforementioned metacognitive beliefs were highly interrelated. By means of the data produced in this study, an improved version of the instrument was constructed. We used this version of the instrument in a follow-up study and identified a set of items to assess a student's 'competence mindedness'. 'Competence mindedness' is defined as the extent to which students are oriented towards coming to understand subject matter in the chemical domain. This orientation is for instance inferred from students' beliefs about chemistry as a coherent body of knowledge and about chemistry learning as a process in which knowledge is actively constructed. We describe a student's score on this scale as the extent to which he is oriented towards developing chemical competence, or, in short, the student's 'competence mindedness'. As an indicator of students' chemical competence we used the so-called 'macro-micro concept'. The macro-micro concept consists of the ability to use the macro perspective (focusing on chemical phenomena on a substance level) and micro perspective on chemistry (focusing on the structure and behavior of subatomic particles) interchangeably. Although the macro-micro concept is considered to be a central chemical competence by many experts in the field of chemistry education, the concept itself is not mentioned explicitely in any Dutch chemistry textbook used in secondary education. Using the final version of the instrument described in chapter 3, relations between the competence mindedness of students and a central chemical competency were assessed in chapter 4. Consequently, an explorative study was conducted in which a small number of chemistry teachers was questioned on the extent to which they paid attention to the macro-micro concept in their own teaching. Five out of nine teachers interviewed, held the opinion that the macro-micro concept should be a part of chemistry teaching and consequently dedicated time in class to this concept. The other teachers that were interviewed, did not mention the macro-micro concept as a central chemical concept in the interviews. In another study, students' use of the macro-micro concept when answering regular chemistry test questions, was examined. From this study, it can be concluded that there are large differences in the students' use of this concept. However, from answers given by the students involved, it can be concluded that they use the macro-micro concept. Following from the last two studies mentioned, two more studies were conducted that focused on the use of the macro-micro concept by students. In particular we were interested in the way students use this concept differently than is to be expected from the sequencing of learning contents in chemistry textbooks. More specifically, we conducted two studies to determine if students' competence mindedness and the way they use the macro-micro concept (i.e. starting from the micro aspect or not) are related. In the first, small-scale, study, we concluded that senior students that are more competence minded, more often take the micro aspect of chemistry as a starting point when relating the micro and macro aspects of chemistry. In a follow-up study, a standardized instrument was used to assess students' use of the macro-micro concept. This instrument made it possible to include a larger sample of students in the study. This study confirmed the results found in the small-scale study: more competence minded students were found to prefer relations between the macro and micro aspects of chemistry that started from the micro aspect. Chapter 5 consists of several studies concerning students' notions about how the chemical domain can be described: their chemical domain beliefs. The development of these notions are considered an important indicator of chemical competence. Relations between students' competence mindedness and aspects of their chemical domain beliefs were examined through a repertory test procedure. More specifically, the students involved in this study were asked to compare the subject of chemistry with several other subjects. Thereby, data were gathered on constructs these students' used to describe the subject of chemistry and how they contrasted with the other subjects or resembled them. In another study, relations between students' chemical domain beliefs and the extent to which these students are competence minded were examined. The results show a number of relations between students' competence mindedness and selections of their chemical domain beliefs: in general, more competence minded students more often use concepts like 'chemistry as a science', 'properties of substances', and 'chemical reactions' to typify chemistry. Having found indications that students' competence mindedness regarding chemistry is related to their learning outcomes, the question arises how students' competence mindedness can be enhanced. Moreover, relations between students' competence mindedness and the learning strategies they deploy, have not been taken into consideration up to this point. In chapter 6, a learning environment was redesigned in the form of a student study guide, that is used as a supplement to the chemistry textbook students were used working with. The main purpose of the study guide was to change the type of learning activities students use. The two quasi-experimental studies in which the study guide was used as an intervention, did not lead to significant changes in students' learning activities. However, relations were found between students' learning activities and the extent to which students were competence minded. We conclude therefore, that the learning strategies used by the students involved in the study are in particular a consequence of their metacognitive beliefs, i.e. their competence mindedness, and not of the learning environment concerned.
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Seven new 1,3,5-cyclohexyltricarboxamide-phenylalanine derivatives were synthesized in order to investigate the effect of the amino acid chirality on the gelating properties of these small molecules in water. Gelation tests have shown that enantiomerically pure homochiral 1,3,5-cyclohexyltricarboxamide-L-phenylalanine is a non-hydrogelator as it crystallizes from water, whereas the heterochiral derivatives with either two L-phenylalanine moieties and one D-phenylalanine (LLD), or vice versa (DDL), are very good hydrogelators. Concentration-dependent gel-to-sol transition-temperature (T(gs)) curves for LLD or DDL gels show a sigmoidal behaviour, which is in contrast to the logarithmic curves generally observed for gels derived from low molecular weight gelators (LMWGs). Such sigmoidal behaviour can be related to interactions between fibre bundles, which give rise to intertwined bundles of fibres. Transmission electron microscopy (TEM) images of LLD and DDL gels show a network of thin, unbranched, fibre bundles with diameters of 20 nm. Right-handed twisted fibre bundles are present in the LLD gel, whereas left-handed structures can be found in the DDL gel. Each bundle of fibres consists of a finite number of primary fibres. Gels consisting of mixtures of gelators, LLD and DDL, and nongelators (LLL or DDD) were investigated by means of T(gs) measurements, CD spectroscopy and TEM. Results show that the incorporation of nongelator molecules into gel fibres occurs; this leads to higher T(gs) values and to changes in the helicity of the fibre bundles. Furthermore, it was found that peripheral functionalization of the homochiral derivatives LLL or DDD by means of a second amino acid or a hydrophilic moiety can overcome the effect of chirality; this process in turn leads to good hydrogelators.
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The concurrent self-assembly of new 1,3,5-trisamide-cyclohexane-based low molecular weight hydrogelators and various surfactants in water leads to the formation of self-assembled fibrillar networks with encapsulated micelles. This prototype system presents an example of orthogonal self-assembly, that is, the independent formation of two different supramolecular structures, each with their own characteristics that coexist within a single system.
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The reaction of the alkyl complexes Cp*2LnCH(SiMe 3)2 (Ln = Y 1-Y, Ce 1-Ce, La 1-La; Cp* = η5-C5Me5) and Me2Si(η 5-C5Me4)2LnCH(SiMe3) 2 (Ln = Ce 5-Ce) with 1-methylalk-2-ynes CH3C≡CR (R = Me 3a, Et 3b, nPr 3c, tBu 3d, SiMe3 3e, Ph 3f, C6H4Me-2 3g, C6H3Me 2-2,6 3h, C6H3iPr2-2,6 3i, C6F5 3j) affords the corresponding η3-propargyl/allenyl complexes Cp*2LnCH 2CCR (4a-j-Ln) and Me2Si(η5-C 5Me4)2CeCH2CCR (6a-j-Ce) via propargylic metalation. The hydride complexes [Cp*2Ln(μ-H)] 2 (Ln = Y 2-Y, Ce 2-Ce, La 2-La) react rapidly with 3 to produce mixtures of insertion and propargylic metalation products, and the relative rate of these processes depends on the metal and alkyne substituent. Selected η3-propargy/allenyl complexes Cp*2YCH 2CCR (R = Me 4a-Y, Ph 4f-Y), Cp*2CeCH2CCR (R = Me 4a-Ce, Ph 4f-Ce), Cp*2CeCH(Me)CCEt (9b-Ce), Cp*2LaCH2CCR (R = Ph 4f-La, C6H 3Me2-2,6 4h-La) are obtained on a preparative scale and characterized by NMR spectroscopy, IR spectroscopy, and cryoscopy. Compounds 4f-Y and 4f-La are also characterized by single-crystal X-ray diffraction. The reactions of the η3-propargyl/allenyl complexes with Brønsted acids, such as alcohols and acetylenes, afford the corresponding substituted allenes (RCH=C=CH2) and 1-methylalk-2-ynes (CH 3C≡CR) as organic products. The reactions of 4f-Y and 4f-La with Lewis bases, such as pyridine and THF, yield die corresponding base adducts. The adduct 4f-La · py is characterized by single-crystal X-ray diffraction, revealing an η3-coordinated propargyl/allenyl ligand. © 2008 American Chemical Society.
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Thrips are one of the most challenging pests in agricultural crops, including Chrysanthemum. In this study we tested via two plant assays whether solutionscontaining sticky rice germ oil (RGO) droplets could effectively trap thrips andlower thrips damage on Chrysanthemum. Trefwoorden: biomimicry, duurzame gewasbescherming, trips, biopesticide
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