Publications by year
2021
Burr S, Martin T, Edwards J, Ferguson C, Gilbert K, Gray C, Hill A, Hosking J, Johnstone K, Kisielewska J, et al (2021). Standard setting anchor statements: a double cross-over trial of two different methods. MedEdPublish, 10(1).
2019
Neve H, Gilbert K, Lloyd H (2019). PBL AS LEARNING VEHICLE, THRESHOLD CONCEPT OR CAPABILITY?: Audio-Diary Research in Medical Education. In (Ed) Threshold Concepts in Problem-based Learning, 49-64.
2018
Neve H, Bull S, Lloyd H, Gilbert K, Mattick K (2018). Evaluation of an innovative, evidence-guided, PBL approach.
Clin Teach,
15(2), 156-162.
Abstract:
Evaluation of an innovative, evidence-guided, PBL approach.
AIM: to understand the experiences of students and problem-based learning (PBL) facilitators during an evidence-based curriculum change to a PBL programme within an undergraduate medical course in South West England. METHODS: Four novel PBL cases were designed and implemented, based on educational theory and evidence. Eight focus groups were undertaken with Year-1 and -2 students (n = 18) and PBL facilitators (n = 14) to explore the experiences of participants. Thematic analysis and conceptual abstraction led to insights into the intended and unintended consequences of the change. RESULTS: Participant responses to the change process were influenced by the perceived relevance and value of the change (e.g. benefit to student learning), which was shaped by individual beliefs and preferences (e.g. presumed purpose of PBL, relative value placed on different curriculum topics, and desire for uniform educational experience), and the wider education context (e.g. expectations of assessment). It appears that the three distinct elements must align for the changes to be received positively. We updated our PBL curriculum in response to new evidence DISCUSSION: This study describes how we updated our PBL curriculum in response to new evidence, and demonstrates the importance of communicating the pedagogic rationale behind changes, and meticulous planning, preparation and alignment, even in distant parts of the curriculum. Engaging with existing views and attitudes is an essential requirement for successful curriculum change.
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Author URL.
2016
Gilbert KG (2016). Dyes. In (Ed)
Encyclopedia of Applied Plant Sciences, 368-373.
Abstract:
Dyes
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2006
Sales E, Kanhonou R, Baixauli C, Giner A, Cooke D, Gilbert K, Arrillaga I, Segura J, Ros R (2006). Sowing date, transplanting, plant density and nitrogen fertilization affect indigo production from Isatis species in a Mediterranean region of Spain.
Industrial Crops and Products,
23(1), 29-39.
Abstract:
Sowing date, transplanting, plant density and nitrogen fertilization affect indigo production from Isatis species in a Mediterranean region of Spain
The increasing interest in natural products from a renewable source has encouraged growers to reintroduce indigo-producing crops into the European agriculture. We studied agronomic conditions (sowing date, plant density, nitrogen fertilization, irrigation rate, seedling transplanting) influencing production of the blue pigment indigo, from Isatis tinctoria and I. indigotica crops in a Mediterranean region of Spain (Valencia). I. tinctoria was more suitable for cultivation in our climate conditions than I. indigotica. Indigo yield from Spanish I. tinctoria trials was greater than in Northern and Central Europe. Furthermore, indigo production was maintained when water and nitrogen supplies were significantly restricted, showing that I. tinctoria is not a high-demanding crop. © 2005 Elsevier B.V. All rights reserved.
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2004
Gilbert KG, Maule HG, Rudolph B, Lewis M, Vandenburg H, Sales E, Tozzi S, Cooke DT (2004). Quantitative analysis of indigo and indigo precursors in leaves of Isatis spp. and Polygonum tinctorium.
Biotechnology Progress,
20(4), 1289-1292.
Abstract:
Quantitative analysis of indigo and indigo precursors in leaves of Isatis spp. and Polygonum tinctorium
Analysis of extracts from two woad species (Isatis tinctoria and Isatis indigotica) and Polygonum tinctorium revealed that only one indigo precursor (indican) was present in Polygonum, but two precursors were found in Isatis spp. This was done using high performance liquid chromatography (HPLC), coupled to an evaporative light scattering detector (ELSD). In Isatis spp. the indigo precursors indican and a fraction representing isatan B were identified. The proportion of indican and isatan B was different between the two Isatis spp. tested. For the first time, it was possible to quantify the precursors in woad plant species, and the results were found to be in good agreement with those made from total indigo quantification using two different spectrophotometric methods or a derivatization technique.
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2003
Angelini LG, Campeol E, Tozzi S, Gilbert KG, Cooke DT, John P (2003). A New HPLC-ELSD Method to Quantify Indican in Polygonum tinctorium L. and to Evaluate β-Glucosidase Hydrolysis of Indican for Indigo Production.
Biotechnology Progress,
19(6), 1792-1797.
Abstract:
A New HPLC-ELSD Method to Quantify Indican in Polygonum tinctorium L. and to Evaluate β-Glucosidase Hydrolysis of Indican for Indigo Production
A method to quantify the indigo precursor indican (indoxyl-β-D- glucoside) in Polygonum tinctorium L. has been developed. Plant material was extracted in deionized water, and indican was identified and quantified using high performance liquid chromatography (HPLC) coupled to an evaporative light scattering detector (ELSD). Results confirmed that with this method it is possible to measure indican content in a short time, obtaining reliable and reproducible data. Using this method, leaf indican content was quantified every 15 days during the growing season (from May to October) in P. tinctorium crops grown in a field experiment in Central Italy. Results showed that indican increased along the growing season until flowering and was positively affected by photosynthetic active radiation (PAR). Indican is naturally hydrolyzed by native β-glucosidase to indoxyl and glucose, the indoxyl yielding indigo. The activity of two enzymes, sweet almond β-glucosidase and Novarom G preparation, were compared with P. tinctorium native β-glucosidase to evaluate indigo production. Results showed that the ability to promote indigo formation increased as follows: almond β-glucosidase ≤ Novarom G.
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2002
Gilbert KG, Garton S, Karam MA, Arnold GM, Karp A, Edwards KJ, Cooke DT, Barker JHA (2002). A high degree of genetic diversity is revealed in Isatis spp. (dyer's woad) by amplified fragment length polymorphism (AFLP).
Theoretical and Applied Genetics,
104(6-7), 1150-1156.
Abstract:
A high degree of genetic diversity is revealed in Isatis spp. (dyer's woad) by amplified fragment length polymorphism (AFLP)
Genetic diversity in 38 genotypes, representing 28 individual genotypes from five landraces of Isatis tinctoria (three German: Tubingen, Potsdam and Erfurt, one Swiss and one English), five genotypes of Isatis indigotica (Chinese woad) and five genotypes of Isatis glauca, were investigated using AFLP analysis. Five primer combinations detected a total of 502 fragments of which 436 (86.9%) were polymorphxc. The level of polymorphism recorded within each species was 29.8, 86.9 and 35.8% for I. indigotica, I. tinctoria and I. glauca, respectively. Clearly, genetic diversity within I. tinctoria was greater than that observed in I. indigotica or I. glauca. Cluster analyses of the AFLP data using UP-GMA and PCO revealed the complete separation of the genotypes of each species into distinct groups. I. indigotica separated as an entirely independent group, whereas I. glauca formed a separate cluster within the I. tinctoria group. Indeed, I. tinctoria and I. glauca are more closely related to each other than either is to I. indigotica. In addition, the genotypes of each landrace, apart from one from the English group, were clearly discriminated. However, the anomalous genotype did associate with the rest of its group when it was linked with the Erfurt group. These results provide new and useful information about the make-up of the Isatis genome, which has not previously been evaluated. They will be useful in the selection of plant material for variety development and conservation of the gene-pool.
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2001
Gilbert KG, Cooke DT (2001). Dyes from plants: Past usage, present understanding and potential.
Plant Growth Regulation,
34(1), 57-69.
Abstract:
Dyes from plants: Past usage, present understanding and potential
Prior to the synthesis of dyes from by-products of the petrochemical industry all colour was derived from natural sources, including plants. As the awareness of the need to preserve our natural resources increases and attitudes change towards achieving this, interest is growing in finding renewable resources, which can be used as alternatives. Recent work, to discover whether it is possible to use plants as commercially viable sources of dyes has highlighted a significant resource, which would benefit both industrial production and consumer choice. However, because of the multiplicity of products available, customer expectation is very high. This means that in order to satisfy this demand for high quality and choice, the plants in question must be studied more closely to allow breeding of useful lines and improved economic returns.
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2000
Gilbert KG, Hill DJ, Crespo C, Mas A, Lewis M, Rudolph B, Cooke DT (2000). Qualitative analysis of indigo precursors from woad by HPLC and HPLC-MS.
Phytochemical Analysis,
11(1), 18-20.
Abstract:
Qualitative analysis of indigo precursors from woad by HPLC and HPLC-MS
A qualitative method has been devised to analyse the indigo precursors in leaf extracts of woad (Isatis spp.) using HPLC coupled to an evaporative light scattering detector and confirmed using HPLC coupled, on line, to a particle beam mass spectrometer. Using this technique, indican has been positively identified in shoot extracts of European (I. tinctoria) and Chinese (I. indigotica) woad. Greater amounts of indican were found in the Chinese compared with the European woad.
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Gilbert KG, Hill DJ, Crespo C, Mas A, Lewis M, Rudolph B, Cooke DT (2000). Qualitative analysis of indigo precursors from woad by HPLC and HPLC-MS.
PHYTOCHEMICAL ANALYSIS,
11(1), 18-20.
Author URL.
1998
Stoker KG, Cooke DT, Hill DJ (1998). An improved method for the large-scale processing of woad (Isatis tinctoria) for possible commercial production of woad indigo.
Journal of Agricultural and Engineering Research,
71(4), 315-320.
Abstract:
An improved method for the large-scale processing of woad (Isatis tinctoria) for possible commercial production of woad indigo
The increasing use of alternative crops has meant the introduction of new technologies to process their products. In this work, an alternative method is presented for the extraction of natural indigo from woad (Isatis tinctoria) based on a technique used to extract indigo from Indigofera spp. This method does not rely on the old fermentation procedure used throughout Northern Europe and is cheap, clean and efficient. Evolved from laboratory-based tests, it involves steeping the leaves at low pH in warm water and extracting the indigo at a higher pH, followed by ultra-filtration of the product, which is then left to air-dry. Problems encountered during the development of the technique and how they were overcome are discussed. © 1998 Silsoe Research Institute.
Abstract.
Stoker KG, Cooke DT, Hill DJ (1998). Influence of light on natural indigo production from woad (Isatis tinctoria).
Plant Growth Regulation,
25(3), 181-185.
Abstract:
Influence of light on natural indigo production from woad (Isatis tinctoria)
In woad (Isatis tinctoria), field observations indicated, that after periods of dry sunny weather, indigo yields increased significantly, suggesting that light intensity and quality affected indigo precursor production. Therefore, woad was grown under different light intensities and in the presence or absence of supplementary UV light. In general, plants supplied with more light produced more indigo than those given lesser light. When plants under greater light regimes were transferred to lesser light conditions, then indigo production declined. The opposite was also true, indicating that greater indigo production can be obtained from plants harvested after periods of increased sunlight.
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