What's the difference between perennial and sempiternal?

Perennial

Definition:

(a.) ing or continuing through the year; as, perennial fountains.
(a.) Continuing without cessation or intermission; perpetual; unceasing; never failing.
(a.) Continuing more than two years; as, a perennial steam, or root, or plant.
(n.) A perennial plant; a plant which lives or continues more than two years, whether it retains its leaves in winter or not.

Example Sentences:

(1) Eighty micrograms of the topically active parasympatholytic drug ipratropium were applied intranasally four times daily in 20 adults with perennial rhinitis and severe watery rhinorrhoea in a double-blind controlled cross-over trial.
(2) consider the X-ray findings verified in 3 groups of subjects: with Hayfiber, with perennial rhinitis and the last one being a control group.
(3) Eleven children with severe perennial asthma and a poor clinical response to disodium cromoglycate were studied in a 4-month, double blind trial involving 1 month's treatment with placebo, disodium cromoglycate, betamethasone 17 valerate, and both drugs combined according to a predetermined random design.
(4) Cruden Farm, Victoria The 54-hectare Murdoch family estate in Langwarrin south of Melbourne, Australia, features magnificent gardens complete with ponds, lemon-scented gum trees and two walled gardens and perennial borders.
(5) In this study, the authors evaluate the inhalant substances of the house, emphasizing the importance of Dermatophagoides pteronyssinus to cause perennial allergic rhinitis.
(6) A panel of human CD4+ T cell clones specific for the house dust mite was isolated from an atopic individual with perennial rhinitis.
(7) Patients who had both perennial symptoms and summer seasonal exacerbations had a higher incidence of a positive family history of atopy and developed symptoms earlier in life than those patients who had summer seasonal or perennial symptoms only.
(8) Patients with perennial rhinitis had a more vigorous response than the controls.
(9) The immediate changes in regional ventilation and pulmonary blood flow were studied in seventeen adults with perennial asthma and in two control persons, who were challenged by histamine inhalation (histamine induced asthma (HIA)).
(10) Twenty-eight patients with allergic perennial rhinitis treated for 2 years with parenteral semidepot immunotherapy were divided into two groups of 14 patients: group A receiving conventional aerosol nebulization (TNE), and group B, which received TNAI using a type F aerosol electrocompressor.
(11) We have something to say and something to offer on perennial political dilemmas.
(12) Specificity was 87% for pollens and 90% for perennial antigens.
(13) Overnight, Russia has moved from perennial rival to trusted friend, while Nato’s future is in peril.
(14) More males than females had summer seasonal symptoms whereas more females than males had perennial symptoms.
(15) The old-fashioned dining room, unpretentious atmosphere, and the three-course menus under €30 make it a perennial favourite.
(16) But Howitt says that while it is a problem that so much farmland has shifted from more adjustable crops to perennials like almonds, he has a simpler solution: better management of groundwater.
(17) They are the identification of factors causing severe disease as opposed to heavy infection; the effects of seasonal as opposed to perennial transmission; and the importance of transplacental transmission of microfilariae or soluble antigens.
(18) Together with his late wife Janet, he wrote 37 titles including perennial favourites The Jolly Postman and Burglar Bill, and by himself he is the author of many more, including The Pencil, and Woof!
(19) It seems that perennial rhinitis probably arises from abundance of domestic antigens more than for the other allergic manifestations, as the nose is the first filter to receive foreign particles.
(20) However, PAC differed from SAC in several respects: a history of exacerbation on exposure to house dust (PAC 42 per cent; SAC none) and an association with perennial rhinitis (PAC 75 per cent; SAC 12 per cent) were more common in PAC.