Vasodilators are medications that open (dilate) blood vessels. They work directly on the muscles in the walls of your arteries, preventing the muscles from tightening and the walls from narrowing. The blood flows more easily through your arteries, your heart doesn't have to pump as hard and your blood pressure is reduced. The best vasodilators depend on the health and the condition being treated. The use of vasodilators to prevent, treat or improve symptoms in a variety of conditions, such as high blood pressure, high blood pressure during pregnancy or childbirth (preeclampsia or eclampsia), heart failure and high blood pressure that affects the arteries in your lungs (pulmonary hypertension) The impact factor of journal provides quantitative assessment tool for grading, evaluating, sorting and comparing journals of similar kind. It reflects the average number of citations to recent articles published in science and social science journals in a particular year or period, and is frequently used as a proxy for the relative importance of a journal within its field. It is first devised by Eugene Garfield, the founder of the Institute for Scientific Information. The impact factor of a journal is evaluated by dividing the number of current year citations to the source items published in that journal during the previous two years.