The winning entry, Calcium rainbowCharlotte Buckley, University of Strathclyde, British Heart Foundation Reflections of ResearchThe muscle cells lining an artery resemble a stained glass window in this image, the winner of the British Heart Foundations annual Reflections of Research competition. Scientists funded by the charity submitted the most striking pictures from their work on heart and circulatory conditions.Charlotte Buckley at the University of Strathclyde, UK, who scooped first prize, is exploring how cells in artery walls respond to calcium levels and how this leads to high blood pressure, stroke and dementia. A fluorescent dye shows calcium levels at different times in a recording: blue shows this mineral released from stores inside cells at the start, while later emissions run through purple, pink, red, orange, yellow and then white. AdvertisementThe powerhouse of lifeAgustina Salis Torres, University of Edinburgh, British Heart Foundation Reflections of ResearchAnother image, a shortlisted entry by Agustina Salis Torres at the University of Edinburgh, UK, also shows muscle cells that line blood vessels. The nuclei, which contain genetic material, are shown in blue, and calcium is labelled in green. Mitochondria, the energy-generating parts of the cells, are stained yellow and orange.Igniting a new wave of AF researchAaron Johnston, University of Oxford, British Heart Foundation Reflections of Research Get the most essential health and fitness news in your inbox every Saturday.Sign up to newsletterThe image above shows a cell collected from the heart of a person with an irregular heartbeat due to a condition called atrial fibrillation (AF). The glowing strands of orange and yellow highlight a protein called filamin-A that helps cells respond to each other, and which becomes altered in the condition. The blue oval shows the nucleus of the cell. Aaron Johnston at the University of Oxford, who captured the image, hopes that understanding how cells change during AF could lead to new treatments.Blooming developmentVictoria Rashbrook, University of Oxford, British Heart Foundation Reflections of ResearchVictoria Rashbrook at the University of Oxford, who is studying how pregnancy and infant health affects heart development, took this image of a developing mouse embryo halfway through pregnancy. Resembling a tulip in bloom, the pink petals develop into the head, the green stem expands to form the body and the green roots depict the placenta.The Heartbeat of Tooth! Bridging Oral and Cardio HealthSusanth Alapati, University of Aberdeen, British Heart Foundation Reflections of ResearchSusanth Alapati at the University of Aberdeen, UK, produced this image to highlight how poor dental hygiene can cause bacteria to enter the bloodstream, and this in turn can ramp up inflammation in the heart and arteries, raising the risk of heart disease. Staphylococcus bacteria that live in the mouth were used to construct the shape of a tooth, while the heart was formed using gum bacteria called Porphyromonas. Alapati is researching links between oral and heart health to find ways to prevent heart disease.Topics:The heart