What's the difference between calcium and chalk?

Calcium


Definition:

  • (n.) An elementary substance; a metal which combined with oxygen forms lime. It is of a pale yellow color, tenacious, and malleable. It is a member of the alkaline earth group of elements. Atomic weight 40. Symbol Ca.

Example Sentences:

  • (1) In studies of calcium metabolism in 13 unselected patients with untreated sarcoidosis all were normocalcaemic but five had hypercalcuria.
  • (2) After stimulation with lipopolysaccharide and calcium ionophore A23187, culture supernatants of clones c18A and c29A showed cytotoxic activity against human melanoma A375 Met-Mix and other cell lines which were resistant to the tumor necrosis factor, lymphotoxin and interleukin 1.
  • (3) The half-life of 45Ca in the various calcium fractions of both types of bone was 72 hours in both the control and malnourished groups except the calcium complex portion of the long bone of the control group, which was about 100 hours.
  • (4) Calcium alginate dressings have been used in the treatment of pressure ulcers and leg ulcers.
  • (5) of PLA2 caused marked degranulation of mast cells in the rat mesentery which was facilitated by addition of calcium ion (10 mM) but antagonized by pretreating with three antiinflammatory agents.
  • (6) Thus adrenaline, via pre- and post-junctional adrenoceptors, may contribute to enhanced vascular smooth muscle contraction, which most likely is sensitized by the elevated intracellular calcium concentration.
  • (7) It includes preincubation of diluted plasma with ellagic acid and phospholipids and a starting reagent that contains calcium and a chromogenic peptide substrate for thrombin, Tos-Gly-Pro-Arg-pNA.
  • (8) The results show that endolymph is extremely inhomogenous with respect to calcium potentials.
  • (9) The occupation of the high affinity calcium binding site by Ca(II) and Mn(II) does not influence the Cu(II) binding process, suggesting that there is no direct interaction between this site and the Cu(II) binding sites.
  • (10) This was unlike the action of the calcium channel blocker, cadmium, which reduced the calcium action potential and the a.h.p.
  • (11) Increases in extracellular calcium antagonized the negative inotropic effect.
  • (12) Plasma membranes were isolated from rat kidney and their transport properties for sodium, calcium, protons, phosphate, glucose, lactate, and phenylalanine were investigated.
  • (13) In experiments performed to determine whether PtdIns(4,5)P2 hydrolysis induced by TRH may have been caused by the elevation of [Ca2+]i, the following results were obtained: the effect of TRH to decrease the level of PtdIns(4,5)P2 was not reproduced by the calcium ionophore A23187 or by membrane depolarization with 50 mM K+; the calcium antagonist TMB-8 did not inhibit the TRH-induced decrease in PtdIns(4,5)P2; and, most importantly, inhibition by EGTA of the elevation of [Ca2+]i did not inhibit the TRH-induced decrease in PtdIns(4,5)P2.
  • (14) The distribution of gelsolin, a calcium-dependent actin-severing and capping protein, in the retina of the developing and adult rabbit was studied.
  • (15) In K+-depolarized basilar arteries, ifenprodil competitively antagonized the response to Ca2+, and this was enhanced by pre-incubation in calcium hopantenate.
  • (16) Thirty of the 32 women of the calcitonin group and 27 of 28 women of the calcium group finished treatment.
  • (17) The influence of calcium ions on the electrophoretic properties of phospholipid stabilized emulsions containing various quantities of the sodium salts of oleic acid (SO), phosphatidic acid (SPA), phosphatidylinositol (SPI), and phosphatidylserine (SPS) was examined.
  • (18) Hypercalcitoninemia was the most pronounced in patients with cardiac rhythm disorders and a simultaneous reduction in total serum calcium.
  • (19) The effects of low doses of dihydropyridine (DHP) calcium channel antagonists nimodipine, nifedipine, (-)-R-202-791, and amlodipine, the DHP calcium channel agonist BAY K 8644 were investigated on clonic convulsions to pentylenetetrazole (PTZ) in mice.
  • (20) A comprehensive review of the roentgenographic features of calcium pyrophosphate crystal deposition disease (pseudogout) is presented.

Chalk


Definition:

  • (n.) A soft, earthy substance, of a white, grayish, or yellowish white color, consisting of calcium carbonate, and having the same composition as common limestone.
  • (n.) Finely prepared chalk, used as a drawing implement; also, by extension, a compound, as of clay and black lead, or the like, used in the same manner. See Crayon.
  • (v. t.) To rub or mark with chalk.
  • (v. t.) To manure with chalk, as land.
  • (v. t.) To make white, as with chalk; to make pale; to bleach.

Example Sentences:

  • (1) The young screenwriters possibly needed to have chalked up a few miles before they could deliver really workable scripts."
  • (2) The blue skipping rope – that’s the key to this race.” My eight-year-old daughter looked at me like I was mad … but when it came time for the year 3 skipping race, she did as she was told – and duly chalked up a glorious personal best in third place.
  • (3) His flicked header into the net seconds later, chalked off by an offside flag, confirmed the forward's luck was not in.
  • (4) Inside the first 10 minutes, Boyd hit the bar and Lukas Jutkiewicz saw a goal correctly chalked off for offside, while Danny Ings headed just wide at 2-1, and substitute Ashley Barnes struck the bar late on.
  • (5) France chalked up growth of 0.5%, beating economists' expectations, the best growth figures Fran ç ois Hollande has seen since he was elected president 15 months ago.
  • (6) 2) If the board and adjacent ones are firmly fixed, dust talc or chalk through the cracks to stop them rubbing together.
  • (7) The phrase chalk and cheese springs to mind, or as the French say jour et nuit – day and night.
  • (8) Remember the Theater People: the gal rigging lights for her community theater's production of The Chalk Garden in Brainerd, Minnesota.
  • (9) The house was later covered in chalk and finally became a curious white landmark.
  • (10) It is recommended that overall average and chalk carving be given equal emphasis in the selection process.
  • (11) HS2’s barrister, James Strachan QC, was listening closely, however, and addressed specific points with a lawyer’s care to make no rash promises: HS2’s noise would be less than traffic on the A413; HS2 were working with the RSPB to “mitigate” for barn owls; and, “If there’s a need for chalk grassland, that’s the sort of thing that can be put into these areas to compensate.” Wendy Gray was allowed to respond: “It’s very difficult to be reassured on an unknown quantity,” she said.
  • (12) According to the sonographic pattern and to the scintigraphic imaging the focal lesions were analysed as micro- or macrofollicular adenomas, autonomous adenomas, cysts and chalk.
  • (13) Shortly after arriving in Rome, Las Vegas and Tallinn, however, the lines of gameless resolve I had chalked across my mind were wiped clean.
  • (14) The economy is forecast to chalk up only 0.75% growth this year, and to contract by 1% in 2009 - which would be the first full year of contraction since 1991.
  • (15) Look, Newsnight is made by 13-year-olds,” he said, speaking at the Chalke Valley history festival about his new book on the first world war.
  • (16) A series of 75 spoilt soft lenses with opacities (mostly manifesting as discrete spots or as large areas of cloudiness, chalk-white in appearance) were subjected to histochemical, electron microscopical, electron probe x-ray microanalytical, x-ray diffraction, atomic absorption spectro-photometric, and biochemical analyses.
  • (17) A suspension of chalk powder was injected into the cavity of the urinary bladder of Fischer 344 rats.
  • (18) The reactivity of soils varies widely as geological and sedimentological conditions offer typical but different environments: gravels, chalk soil, clay, salt soils, sands, cave earths are examples of this wide variety, including atmospheric and biogenetic implications.
  • (19) A staircase descends steeply into a network of tunnels and cellars that lead to extraordinary old chalk pits.
  • (20) Photograph: Graham Turner for the Guardian But to date, the prospect of building on abandoned north Kent chalk quarries, has been so unattractive to housebuilders that they have delivered homes at the rate of just 25 a year when 1,000 a year are needed.