Konstantinos Gkrintzalis
Dr.
I am a biologist with significant expertise in Redox Biology and its applications in Biosciences. My postgraduate research focused on clinical biochemistry and following on the sclerotial metamorphosis of filamentous fungi in relation to oxidative stress. As a postdoc I employed biochemical and metabolomic approaches within the fields of nanotoxicology, cell toxicology and ecotoxicology. I am an assistant professor and a SIRG awardee on an research trajectory within applications of Biochemistry in Microbial Physiology and Systems Ecotoxicology. I have established the first freshwater organisms facility in the School of Biotechnology.
Peer Reviewed Journal
| Year | Publication | |
|---|---|---|
| 2025 | Emma Rowan; Anne Leung; Katie O’Rourke; Xiaofei Yin; Lorraine Brennan; Konstantinos Grintzalis (2025) 'New Approach Methodologies: Physiological responses of daphnids to pharmaceutical mixtures'. Journal of Hazardous Materials Letters, . [Link] [DOI] | |
| 2025 | Emma Rowan; Anne Leung; Konstantinos Grintzalis (2025) 'Increasing the carbon chain length of imidazolium ionic liquids impacts their toxicity on daphnids'. Journal of Ionic Liquids, . [Link] [DOI] | |
| 2025 | Emma Rowan; Flavia Melati Chiappara; Harry Esmonde; Konstantinos Grintzalis (2025) 'A miniaturised method for feeding rate in daphnids–A physiology endpoint for risk assessment'. NAM Journal, . [Link] [DOI] | |
| 2025 | Anna Michalaki; Xiaofei Yin; Lorraine Brennan; Konstantinos Grintzalis (2025) 'Exposure to chemical and commercial forms of NSAIDs at environmentally relevant concentrations exert transgenerational metabolic responses in daphnids'. Water Biology and Security, . [Link] [DOI] | |
| 2024 | Emma Rowan; Anne Leung; Konstantinos Grintzalis (2024) 'A Novel Method for the Assessment of Feeding Rate as a Phenotypic Endpoint for the Impact of Pollutants in Daphnids'. Environmental Toxicology and Chemistry, . [Link] [DOI] | |
| 2024 | Anne Leung; Emma Rowan; Flavia Melati Chiappara; Konstantinos Grintzalis (2024) 'The Impact of Parabens and Their Mixtures on Daphnids'. WATER, . [Link] [DOI] | |
| 2024 | Dimitrios Kakavas; Konstantinos Panagiotidis; Keith D. Rochfort; Konstantinos Grintzalis (2024) 'Miniaturizing Nanotoxicity Assays in Daphnids'. Animals, . [Link] [DOI] | |
| 2023 | Yongda Li; Keith D. Rochfort; David Collins; Konstantinos Grintzalis (2023) 'Development of Sensitive Methods for the Detection of Minimum Concentrations of DNA on Martian Soil Simulants'. Life, . [Link] [DOI] | |
| 2023 | Katie O’Rourke; Christina Virgiliou; Georgios Theodoridis; Helen Gika; Konstantinos Grintzalis (2023) 'The impact of pharmaceutical pollutants on daphnids – A metabolomic approach'. Environmental Toxicology and Pharmacology, . [Link] [DOI] | |
| 2023 | Anna Michalaki; Konstantinos Grintzalis (2023) 'A Multiparametric Protocol for the Detailed Phytochemical and Antioxidant Characterisation of Plant Extracts'. Methods and protocols, . [Link] [DOI] | |
| 2023 | Li, Y; Collins, D; Grintzalis, K (2023) 'A simple approach for the detection of Escherichia coli as a model bacterium on Martian soil simulants: A proof of concept study'. Journal of Microbiological Methods, 210 . [DOI] | |
| 2023 | Manikandan, N. Arul, McCann, Ronan, Dimitrios, Kakavas, Rochfort, Keith D., Sreenilayam, Sithara P., Alkan, Godze, Stornetta, Tom, McGivern, Allan Robert, Grintzalis, Konstantinos, Friedrich, Bernd, Foley, Greg, Brabazon, Dermot and Freeland, Brian (2023) 'Production of Silver Nano-Inks and Surface Coatings for Anti-Microbial Food Packaging and Its Ecological Impact'. International Journal of Molecular Sciences, 24 . [Link] https://doi.org/10.3390/ijms24065341 | |
| 2023 | Anna Michalaki; Konstantinos Grintzalis (2023) 'Acute and Transgenerational Effects of Non-Steroidal Anti-Inflammatory Drugs on Daphnia magna'. Toxics, . [Link] [DOI] | |
| 2023 | Anna Michalaki; Dimitrios Kakavas; Maria Giannouli; Konstantinos Grintzalis (2023) 'Toxicity of “green solvents” - The impact of butyl methylimidazolium ionic liquids on daphnids'. Journal of Ionic Liquids, . [Link] [DOI] | |
| 2023 | Yongda Li; David A. Collins; Konstantinos Grintzalis (2023) 'A Simple Biochemical Method for the Detection of Proteins as Biomarkers of Life on Martian Soil Simulants and the Impact of UV Radiation'. Life, . [Link] [DOI] | |
| 2023 | Katie O’Rourke; Beatrice Engelmann; Rolf Altenburger; Ulrike Rolle-Kampczyk; Konstantinos Grintzalis (2023) 'Molecular Responses of Daphnids to Chronic Exposures to Pharmaceuticals'. International Journal of Molecular Sciences, . [Link] [DOI] | |
| 2023 | Konstantinos Panagiotidis; Beatrice Engelmann; Martin Krauss; Ulrike E. Rolle-Kampczyk; Rolf Altenburger; Keith D. Rochfort; Konstantinos Grintzalis (2023) 'The impact of amine and carboxyl functionalised microplastics on the physiology of daphnids'. Journal of Hazardous Materials, . [Link] [DOI] | |
| 2023 | Dimitrios Kakavas; Konstantinos Panagiotidis; Keith D. Rochfort; Konstantinos Grintzalis (2023) 'Surface-to-Volume Ratio Affects the Toxicity of Nanoinks in Daphnids'. Stresses, . [Link] [DOI] | |
| 2023 | N. Arul Manikandan; Ronan McCann; Dimitrios Kakavas; Keith D. Rochfort; Sithara P. Sreenilayam; Godze Alkan; Tom Stornetta; Allan Robert McGivern; Konstantinos Grintzalis; Bernd Friedrich; Greg Foley; Dermot Brabazon; Brian Freeland (2023) 'Production of Silver Nano-Inks and Surface Coatings for Anti-Microbial Food Packaging and Its Ecological Impact'. International Journal of Molecular Sciences, . [Link] [DOI] | |
| 2023 | Maria Giannouli; Konstantinos Panagiotidis; Keith D. Rochfort; Konstantinos Grintzalis (2023) 'Development and application of a sensitive feeding assay for daphnids based on the ingestion of fluorescent microparticles'. Environmental Science: Advances, . [Link] [DOI] | |
| 2023 | Emma Rowan; Anne Leung; Maria Giannouli; Katie O’Rourke; Konstantinos Grintzalis (2023) 'The Water Flea as a “Canary in the Coal Mine”—Using Phenotypic and Molecular Endpoints to Understand Pollution'. Proceedings, . [Link] [DOI] | |
| 2022 | Anna Michalaki; Allan McGivern; Gernot Poschet; Michael Büttner; Rolf Altenburger; Konstantinos Grintzalis (2022) 'The Effects of Single and Combined Stressors on Daphnids—Enzyme Markers of Physiology and Metabolomics Validate the Impact of Pollution'. Toxics, . [Link] [DOI] | |
| 2022 | Grintzalis, K.; Patsoukis, N.; Papapostolou, I.; Zervoudakis, G.; Kalaitzopoulou, E.; Georgiou, C.D.; Matsokis, N.A.; Panagopoulos, N.T. (2022) 'Alterations in thiol redox state and lipid peroxidation in the brain areas of male mice during aging'. Advances in Redox Research, 6 . [Link] [DOI] | |
| 2021 | (2021) 'Efficacy of Phytocannabinoids in Epilepsy Treatment: Novel Approaches and Recent Advances'. International Journal of Environmental Research and Public Health, . [Link] [DOI] | |
| 2019 | (2019) 'Metabolomic method to detect a metabolite corona on amino-functionalized polystyrene nanoparticles'. Nanotoxicology, . [Link] [DOI] | |
| 2018 | Ben Barka, Z.; Grintzalis, K.; Polet, M.; Heude, C.; Sommer, U.; Ben Miled, H.; Ben Rhouma, K.; Mohsen, S.; Tebourbi, O.; Schneider, Y.-J. (2018) 'A combination of NMR and liquid chromatography to characterize the protective effects of Rhus tripartita extracts on ethanol-induced toxicity and inflammation on intestinal cells'. Journal of Pharmaceutical and Biomedical Analysis, . [Link] [DOI] | |
| 2017 | Grintzalis, K.; Dai, W.; Panagiotidis, K.; Belavgeni, A.; Viant, M.R. (2017) 'Miniaturising acute toxicity and feeding rate measurements in Daphnia magna'. Ecotoxicology and Environmental Safety, . [Link] [DOI] | |
| 2016 | Botsakis, K.; Theodoritsi, S.; Grintzalis, K.; Angelatou, F.; Antonopoulos, I.; Georgiou, C.D.; Margarity, M.; Matsokis, N.A.; Panagopoulos, N.T. (2016) '17β-Estradiol/N-acetylcysteine interaction enhances the neuroprotective effect on dopaminergic neurons in the weaver model of dopamine deficiency'. Neuroscience, . [Link] [DOI] | |
| 2016 | Georgiou, C.D.; Zisimopoulos, D.; Panagiotidis, K.; Grintzalis, K.; Papapostolou, I.; Quinn, R.C.; McKay, C.P.; Sun, H.J. (2016) 'Martian Superoxide and Peroxide O2Release (OR) Assay: A New Technology for Terrestrial and Planetary Applications'. Astrobiology, . [Link] [DOI] | |
| 2016 | Martirosyan, A.; Grintzalis, K.; Polet, M.; Laloux, L.; Schneider, Y.-J. (2016) 'Tuning the inflammatory response to silver nanoparticles via quercetin in Caco-2 (co-)cultures as model of the human intestinal mucosa'. Toxicology Letters, . [Link] [DOI] | |
| 2015 | Grintzalis, K.; Georgiou, C.D.; Schneider, Y.-J. (2015) 'An accurate and sensitive Coomassie Brilliant Blue G-250-based assay for protein determination'. Analytical Biochemistry, . [Link] [DOI] | |
| 2015 | Georgiou, C.D.; Sun, H.J.; McKay, C.P.; Grintzalis, K.; Papapostolou, I.; Zisimopoulos, D.; Panagiotidis, K.; Zhang, G.; Koutsopoulou, E.; Christidis, G.E.; Margiolaki, I. (2015) 'Evidence for photochemical production of reactive oxygen species in desert soils'. Nature Communications, . [Link] [DOI] | |
| 2014 | Grintzalis, K.; Papapostolou, I.; Zisimopoulos, D.; Stamatiou, I.; Georgiou, C.D. (2014) 'Multiparametric protocol for the determination of thiol redox state in living matter'. Free Radical Biology and Medicine, . [Link] [DOI] | |
| 2014 | Alakhras, R.S.; Stephanou, G.; Demopoulos, N.A.; Grintzalis, K.; Georgiou, C.D.; Nikolaropoulos, S.S. (2014) 'DNA fragmentation induced by all-trans retinoic acid and its steroidal analogue EA-4 in C2C12 mouse and HL-60 human leukemic cells in vitro'. Journal of Applied Toxicology, . [Link] [DOI] | |
| 2014 | Grintzalis, K.; Vernardis, S.I.; Klapa, M.I.; Georgiou, C.D. (2014) 'Role of oxidative stress in sclerotial differentiation and aflatoxin B1 biosynthesis in Aspergillus flavus'. Applied And Environmental Microbiology, . [Link] [DOI] | |
| 2013 | Grintzalis, K.; Zisimopoulos, D.; Grune, T.; Weber, D.; Georgiou, C.D. (2013) 'Method for the simultaneous determination of free/protein malondialdehyde and lipid/protein hydroperoxides'. Free Radical Biology and Medicine, . [Link] [DOI] | |
| 2012 | Grintzalis, K.; Georgiou, C.D.; Dailianis, S. (2012) 'Total thiol redox status as a potent biomarker of PAH-mediated effects on mussels'. Marine Environmental Research, . [Link] [DOI] | |
| 2011 | Pytharopoulou, S.; Grintzalis, K.; Sazakli, E.; Leotsinidis, M.; Georgiou, C.D.; Kalpaxis, D.L. (2011) 'Translational responses and oxidative stress of mussels experimentally exposed to Hg, Cu and Cd: One pattern does not fit at all'. Aquatic Toxicology, . [Link] [DOI] | |
| 2010 | Faropoulos, K.; Chroni, E.; Assimakopoulos, S.F.; Mavrakis, A.; Stamatopoulou, V.; Toumpeki, C.; Drainas, D.; Grintzalis, K.; Papapostolou, I.; Georgiou, C.D.; Konstantinou, D. (2010) 'Altered occludin expression in brain capillaries induced by obstructive jaundice in rats'. BRAIN RESEARCH, . [Link] [DOI] | |
| 2009 | Georgiou, C.D.; Papapostolou, I.; Grintzalis, K. (2009) 'Protocol for the quantitative assessment of DNA concentration and damage (fragmentation and nicks)'. Nature Protocols, . [Link] [DOI] | |
| 2009 | Grintzalis, K.; Papapostolou, I.; Assimakopoulos, S.F.; Mavrakis, A.; Faropoulos, K.; Karageorgos, N.; Georgiou, C.; Chroni, E.; Konstantinou, D. (2009) 'Time-related alterations of superoxide radical levels in diverse organs of bile duct-ligated rats'. Free Radical Research, . [Link] [DOI] | |
| 2009 | Chronidou, F.; Apostolakis, E.; Papapostolou, I.; Grintzalis, K.; Georgiou, C.D.; Koletsis, E.N.; Karanikolas, M.; Papathanasopoulos, P.; Dougenis, D. (2009) 'Beneficial effect of the oxygen free radical scavenger amifostine (WR-2721) on spinal cord ischemia/reperfusion injury in rabbits'. Journal of Cardiothoracic Surgery, . [Link] [DOI] | |
| 2008 | Pytharopoulou, S.; Sazakli, E.; Grintzalis, K.; Georgiou, C.D.; Leotsinidis, M.; Kalpaxis, D.L. (2008) 'Translational responses of Mytilus galloprovincialis to environmental pollution: Integrating the responses to oxidative stress and other biomarker responses into a general stress index'. Aquatic Toxicology, . [Link] [DOI] | |
| 2008 | Georgiou, C.D.; Grintzalis, K.; Zervoudakis, G.; Papapostolou, I. (2008) 'Mechanism of Coomassie brilliant blue G-250 binding to proteins: A hydrophobic assay for nanogram quantities of proteins'. Analytical and Bioanalytical Chemistry, . [Link] [DOI] | |
| 2008 | Konstantinou, D.; Mavrakis, A.; Grintzalis, K.; Papapostolou, I.; Assimakopoulos, S.F.; Chroni, E.; Georgiou, C. (2008) 'Quantification of superoxide radical in the brain of rats with experimentally induced obstructive jaundice'. Neurochemical Research, . [Link] [DOI] | |
| 2008 | Georgiou, C.D.; Papapostolou, I.; Grintzalis, K. (2008) 'Superoxide radical detection in cells, tissues, organisms (animals, plants, insects, microorganisms) and soils'. Nature Protocols, . [Link] [DOI] | |
| 2008 | Assimakopoulos, S.F.; Mavrakis, A.G.; Grintzalis, K.; Papapostolou, I.; Zervoudakis, G.; Konstantinou, D.; Chroni, E.; Vagianos, C.E.; Georgiou, C. (2008) 'Superoxide radical formation in diverse organs of rats with experimentally induced obstructive jaundice'. Redox Report, . [Link] [DOI] | |
| 2008 | Assimakopoulos, S.F.; Grintzalis, K.; Thomopoulos, K.C.; Papapostolou, I.; Georgiou, C.D.; Gogos, C.; Vagianos, C.E. (2008) 'Plasma superoxide radical in jaundiced patients and role of xanthine oxidase'. American Journal of the Medical Sciences, . [Link] [DOI] | |
| 2008 | (2008) 'Increased Plasma Superoxide Radical in Patients with Non-Metastatic Colorectal Cancer'. Gastroenterology research, . [Link] [DOI] |
Certain data included herein are derived from the © Web of Science (2025) of Clarivate. All rights reserved.
Honors and Awards
Employment
Other Activities
Research Interests
I am a Biologist with
a focus in Biochemistry by training. My postgraduate research was oriented on Oxidative Stress
and Redox Biology which are crucial to physiological phenomena (i.e. signaling,
aging etc.) and in the underlying mechanisms of several pathological conditions
(i.e. cancer, neurodegenerative diseases).
During my postgraduate studies, I developed novel biochemical methodologies for biomarkers of oxidative stress and specifically for the quantification of protein and lipid peroxidation, DNA fragmentation, thiol redox state, reactive oxygen species, and two ultrasensitive protocols for the quantification of proteins. During my PhD thesis I studied sclerotial metamorphosis and aflatoxin biosynthesis in Aspergillus flavus and provided a biochemical link between these two processes via oxidative stress. I extended this project to a metabolic perspective as a postdoctoral fellow using high-performance liquid chromatography coupled with mass spectrometry. Furthermore, I participated in several collaborations among different fields of research. Specifically, in a collaboration with the astrogeophysicist Dr. Christopher P. McKay (from NASA Ames Research Center) I studied the formation of life-inhibiting oxidants in Mars-like analogue desserts and developed novel biochemical methods useful for planetary research. My biochemical experience allowed me to participate in a diverse set of research projects ranging from bioindicators for environmental pollution, animal models for ischemia/reperfusion injury, in vitro assessment of anticancer drugs, neurodegeneration models and ageing in mice, and clinical samples for obstructive jaundice.
In 2014 I was a postdoctoral fellow at the Université catholique de Louvain, where I worked on the mechanisms of cytotoxicity of silver nanoparticles on human intestinal cells and the protective effects of phenolic antioxidants. I also studied the antioxidant and anti-inflammatory potential of different plant tissue extracts from Rhus tripartitum, an endemic Tunisian medicinal plant, on intestinal cells after exposure to ethanol stress. Following, from 2016 I was a research fellow at the University of Birmingham, working on Environmental Metabolomics withing the context of Molecular Ecotoxicology. I studied the physiology and growth of Daphnia magna using metbaolomic signatures upon exposure to mixtures of chemicals. For my research I developed a miniaturized approach for the acute toxicity and algae feeding and discovered the molecular fingerprints of metabolite coronas on nanomaterials.
In 2017 I joined the School of Biotechnology as an assistant professor and secured prestigious funding from Science Foundation Ireland by a Starting Research Investigator Grant on Environmental Metabolomics. Working in a reputable academic institute with a dynamic, inspiring, and interactive environment in Dublin City University gave me the opportunity to establish the first freshwater organism facility and set out an independent research career. I am actively involved in teaching and research within the School and across it borders participating in various visiting and host activities.
Web of Science: h-Index: 12, 323 Citing Articles without self-citations, 14.33 average citations per item
ORCID: 0000-0002-6276-495X Scopus Author ID 23097934200
During my postgraduate studies, I developed novel biochemical methodologies for biomarkers of oxidative stress and specifically for the quantification of protein and lipid peroxidation, DNA fragmentation, thiol redox state, reactive oxygen species, and two ultrasensitive protocols for the quantification of proteins. During my PhD thesis I studied sclerotial metamorphosis and aflatoxin biosynthesis in Aspergillus flavus and provided a biochemical link between these two processes via oxidative stress. I extended this project to a metabolic perspective as a postdoctoral fellow using high-performance liquid chromatography coupled with mass spectrometry. Furthermore, I participated in several collaborations among different fields of research. Specifically, in a collaboration with the astrogeophysicist Dr. Christopher P. McKay (from NASA Ames Research Center) I studied the formation of life-inhibiting oxidants in Mars-like analogue desserts and developed novel biochemical methods useful for planetary research. My biochemical experience allowed me to participate in a diverse set of research projects ranging from bioindicators for environmental pollution, animal models for ischemia/reperfusion injury, in vitro assessment of anticancer drugs, neurodegeneration models and ageing in mice, and clinical samples for obstructive jaundice.
In 2014 I was a postdoctoral fellow at the Université catholique de Louvain, where I worked on the mechanisms of cytotoxicity of silver nanoparticles on human intestinal cells and the protective effects of phenolic antioxidants. I also studied the antioxidant and anti-inflammatory potential of different plant tissue extracts from Rhus tripartitum, an endemic Tunisian medicinal plant, on intestinal cells after exposure to ethanol stress. Following, from 2016 I was a research fellow at the University of Birmingham, working on Environmental Metabolomics withing the context of Molecular Ecotoxicology. I studied the physiology and growth of Daphnia magna using metbaolomic signatures upon exposure to mixtures of chemicals. For my research I developed a miniaturized approach for the acute toxicity and algae feeding and discovered the molecular fingerprints of metabolite coronas on nanomaterials.
In 2017 I joined the School of Biotechnology as an assistant professor and secured prestigious funding from Science Foundation Ireland by a Starting Research Investigator Grant on Environmental Metabolomics. Working in a reputable academic institute with a dynamic, inspiring, and interactive environment in Dublin City University gave me the opportunity to establish the first freshwater organism facility and set out an independent research career. I am actively involved in teaching and research within the School and across it borders participating in various visiting and host activities.
Web of Science: h-Index: 12, 323 Citing Articles without self-citations, 14.33 average citations per item
ORCID: 0000-0002-6276-495X Scopus Author ID 23097934200
Teaching Interests
My teaching philosophy has been strongly
influenced by my early experiences and my roles initially as a student and
later as a teacher, which shaped my character and perspective in teaching so
far. I will try to sketch my perspective and what motivates me by the following
principles which provide fundamental structure for me as a teacher.
1. Cognitive growth is a developmental process requiring time and patience. A teacher must have patience and will for the important task they are appointed to. This is fundamental, and I thank my teachers for having the time and putting the effort in me first, and now being on the other side, I try to keep this momentum to the maximum for my students.
2. Teachers should focus on strengths and use positive feedback to help learners grow academically, socially, and emotionally. Teachers should emphasize in development of their students on multiple levels. I often find myself organizing my students in groups especially in scientific related activities. I was given this opportunity several times in laboratory projects where simply one person could not physically perform the task. It was cumulative work that awarded everyone with success and the best outcome. An example of teamwork have been the numerous publications from student projects, although the greatest reward was seeing students collaborate and helping each other in the lab.
3. Critical thinking helps students internalize learning. People should not be treated as empty vessels into which knowledge is simply just poured into. Rather, they should be helped to understand the world from their own phenomenological vantage point and in this way develop a critical way of thinking to consolidate information and transform it to new knowledge.
4. Teaching is not static, and teachers must seek continuous renewal and growth. Innovation in teaching is something I dedicate myself to explore novel ways for enriching the teaching material and my methods of approach and lectures. I am constantly revising my lectures and teaching materials as I try to improve myself. By performing self-assessment via questionnaires for teaching evaluation, I take into consideration comments from students and colleagues. So far, I have revised lab manuals and lectures slides and seen the improvement in performance both from my side but from the students’ side, in terms of improvement of exam scores and understanding the curriculum.
1. Cognitive growth is a developmental process requiring time and patience. A teacher must have patience and will for the important task they are appointed to. This is fundamental, and I thank my teachers for having the time and putting the effort in me first, and now being on the other side, I try to keep this momentum to the maximum for my students.
2. Teachers should focus on strengths and use positive feedback to help learners grow academically, socially, and emotionally. Teachers should emphasize in development of their students on multiple levels. I often find myself organizing my students in groups especially in scientific related activities. I was given this opportunity several times in laboratory projects where simply one person could not physically perform the task. It was cumulative work that awarded everyone with success and the best outcome. An example of teamwork have been the numerous publications from student projects, although the greatest reward was seeing students collaborate and helping each other in the lab.
3. Critical thinking helps students internalize learning. People should not be treated as empty vessels into which knowledge is simply just poured into. Rather, they should be helped to understand the world from their own phenomenological vantage point and in this way develop a critical way of thinking to consolidate information and transform it to new knowledge.
4. Teaching is not static, and teachers must seek continuous renewal and growth. Innovation in teaching is something I dedicate myself to explore novel ways for enriching the teaching material and my methods of approach and lectures. I am constantly revising my lectures and teaching materials as I try to improve myself. By performing self-assessment via questionnaires for teaching evaluation, I take into consideration comments from students and colleagues. So far, I have revised lab manuals and lectures slides and seen the improvement in performance both from my side but from the students’ side, in terms of improvement of exam scores and understanding the curriculum.