What's the difference between essential and principal?

Essential


Definition:

  • (a.) Belonging to the essence, or that which makes an object, or class of objects, what it is.
  • (a.) Hence, really existing; existent.
  • (a.) Important in the highest degree; indispensable to the attainment of an object; indispensably necessary.
  • (a.) Containing the essence or characteristic portion of a substance, as of a plant; highly rectified; pure; hence, unmixed; as, an essential oil.
  • (a.) Necessary; indispensable; -- said of those tones which constitute a chord, in distinction from ornamental or passing tones.
  • (a.) Idiopathic; independent of other diseases.

Example Sentences:

  • (1) However, medicines have an important part to play, and it is now generally agreed that for the very poor populations medicines should be restricted to those on an 'essential drugs list' and should be made available as cheaply as possible.
  • (2) The results of the evaluation confirm that most problems seen by first level medical personnel in developing countries are simple, repetitive, and treatable at home or by a paramedical worker with a few safe, essential drugs, thus avoiding unnecessary visits to a doctor.
  • (3) Nucleotide, which is essential for catalysis, greatly enhances the binding of IpOHA by the reductoisomerase, with NADPH (normally present during the enzyme's rearrangement step, i.e., conversion of a beta-keto acid into an alpha-keto acid, in either the forward or reverse physiological reactions) being more effective than NADP.
  • (4) Community involvement is a key element of the Primary Health Care (PHC) approach, and thus an essential topic on a course for managers of Primary Health Care programmes.
  • (5) No significant fatty acid binding by proteins was detected in S. cerevisiae, even when grown on a fatty acid-rich medium, thus indicating that such proteins are not essential to fatty acid metabolism.
  • (6) The UK's standard position on ICC indictees is to avoid all contact unless "essential".
  • (7) In spite of important differences in size, chemical composition, polymer density, and configuration, biological macromolecules indeed manifest some of the essential physical-chemical properties of gels.
  • (8) Most cis AB sera have anti-B activity, essentially at 4 degrees C. In saliva A and H substances are found in normal amounts but B substance is only evidenced by inhibition of autologous cells agglutination.
  • (9) Treatment with trypsin gave essentially one radioactive peptide, the active site peptide, of approximately 2300 molecular weight.
  • (10) We conclude that this enzyme is essentially identical to the native enzyme and should be very useful in the future study of this important hydroxylase.
  • (11) Thus serum ionized calcium in untreated essential hypertensive patients may predict the blood pressure response to the slow calcium channel blocker verapamil.
  • (12) The effects of supervised mild aerobic exercise at the work load of the blood lactate threshold for 10 weeks on serum lipids and apolipoproteins were studied in 24 patients with essential hypertension.
  • (13) No other essential regulatory sequence is located further upstream.
  • (14) Based on the results of the Community AIM Exploratory Action, further collaborative work is required at EEC level to create an Integrated Health Information Environment (IHE) allowing essentially for integration, modularity and security.
  • (15) Ovarian vein sampling for androgen was essential in locating this patient's microscopic tumor.
  • (16) After approximately 20 in vitro passages, Chinese hamster kidney (CHK) cell cultures transformed upon exposure to different strains of SV 40 can show a diploid modal chromosome number of 22 with chromosome counts exclusively or essentially in the diploid range (20-25).
  • (17) An official from Cafcass, the children and family court advisory service, tried to persuade the child in several interviews, but eventually the official told the court that further persuasion was inappropriate and essentially abusive.
  • (18) Of 55 new open reading frames analysed by gene disruption, three are essential genes; of 42 non-essential genes that were tested, 14 show some discernible effect on phenotype and the remaining 28 have no overt function.
  • (19) Essential characteristics of the composite bone cement included a homogeneous and uniform fiber distribution, and a minimal increase in apparent viscosity of the polymerizing cement.
  • (20) The median blood levels were lower in hyperacidic subjects and higher in hypoacidic patients; the urinary excretion of the digitalis compound showed no essential differences.

Principal


Definition:

  • (a.) Highest in rank, authority, character, importance, or degree; most considerable or important; chief; main; as, the principal officers of a Government; the principal men of a state; the principal productions of a country; the principal arguments in a case.
  • (a.) Of or pertaining to a prince; princely.
  • (n.) A leader, chief, or head; one who takes the lead; one who acts independently, or who has controlling authority or influence; as, the principal of a faction, a school, a firm, etc.; -- distinguished from a subordinate, abettor, auxiliary, or assistant.
  • (n.) The chief actor in a crime, or an abettor who is present at it, -- as distinguished from an accessory.
  • (n.) A chief obligor, promisor, or debtor, -- as distinguished from a surety.
  • (n.) One who employs another to act for him, -- as distinguished from an agent.
  • (n.) A thing of chief or prime importance; something fundamental or especially conspicuous.
  • (n.) A capital sum of money, placed out at interest, due as a debt or used as a fund; -- so called in distinction from interest or profit.
  • (n.) The construction which gives shape and strength to a roof, -- generally a truss of timber or iron, but there are roofs with stone principals. Also, loosely, the most important member of a piece of framing.
  • (n.) In English organs the chief open metallic stop, an octave above the open diapason. On the manual it is four feet long, on the pedal eight feet. In Germany this term corresponds to the English open diapason.
  • (n.) A heirloom; a mortuary.
  • (n.) The first two long feathers of a hawk's wing.
  • (n.) One of turrets or pinnacles of waxwork and tapers with which the posts and center of a funeral hearse were formerly crowned.
  • (n.) A principal or essential point or rule; a principle.

Example Sentences:

  • (1) In addition to their involvement in thrombosis, activated platelets release growth factors, most notably a platelet-derived growth factor (PDGF) which may be the principal mediator of smooth muscle cell migration from the media into the intima and of smooth muscle cell proliferation in the intima as well as of vasoconstriction.
  • (2) While stereology is the principal technique, particularly in its application to the parenchyma, other compartments such as the airways and vasculature demand modifications or different methods altogether.
  • (3) Chromatography and immunoassays are the two principal techniques used in research and clinical laboratories for the measurement of drug concentrations in biological fluids.
  • (4) This paper reports, principally, the caries results of the first three surveys of 5, 12 and 5-year-olds undertaken at the end of 1987, 1988 and 1989, respectively.
  • (5) Rigidly fixing the pubic symphysis stiffened the model and resulted in principal stress patterns that did not reflect trabecular density or orientations as well as those of the deformable pubic symphysis model.
  • (6) The binding parameters indicate that the principal activating effect of UMP is not simply to increase the affinity of the enzyme for glucose.
  • (7) Mononuclear phagocytic cells from patients with either principal form of leprosy functioned similarly to normal monocytes in phagocytosis while their fungicidal activity for C. pseudotropicalis was statistically significantly altered and was more evident in the lepromatous than in the tuberculoid type.
  • (8) In the terminal segment of the hamster epididymidis there was some evidence of micro-merocrine protein secretion a the level of the principal cells and clear evidence of granular secretion in the light cells, presumable of glycoproteins.
  • (9) In the analysis of background fluorescence, the principal components were, as for the two-step technique, autofluorescence and propidium spectral overlap.
  • (10) However, at Period B, neutrophil numbers in the BAL fluid were increased in the principal but not in the control animals.
  • (11) Principal conclusions are: 1) rapid change to predominantly heterosexual HIV transmission can occur in North America, with serious societal impact; 2) gender-specific clinical features can lead to earlier diagnosis of HIV infection in women; 3) HIV infection in women does not pursue an inherently more rapid course than that observed in men.
  • (12) The concentrations of the principal extratesticular androgens and estradiol do not seem to have a quantitative influence on these androphilic proteins either.
  • (13) A principal function of GPIb is its attachment to von Willebrand Factor (vWF) on injured blood vessels which leads to the adhesion of platelets to these vessels.
  • (14) The principal variables influencing a particular configuration and their effects are indicated.
  • (15) The principal form of HMTs produced by these human peripheral blood monocytes has been subjected to biochemical, functional, and serological characterization.
  • (16) Micronutrient antioxidants such as alpha-tocopherol, the principal lipid-soluble antioxidant, assume potential significance because levels can be manipulated by dietary measures without resulting in side effects.
  • (17) Cytochrome oxidase histochemistry revealed patchy patterns of the enzyme activity in transverse sections through the caudal part of the ventral subnucleus of the principal sensory trigeminal nucleus, interpolar spinal trigeminal nucleus, and layer IV of the caudal spinal trigeminal nucleus in the cat.
  • (18) 3. an up-to-date review of the principal methods and systems used to measure the sedimentation rate--Automation of the Westergren initial methodology.
  • (19) • Queen Margaret Union, one of the University of Glasgow's two student unions, says 200 students there are marching on the principal's office at the moment to present an anti-cuts petition.
  • (20) This observation provides corroboration for the identification of the principal CCK-I neuron in the rat olfactory bulb as the centrally projecting middle tufted cell.