ELIZA

return kwic search for first out of >500 occurrences
378430 occurrences (No.48 in the rank) during 5 years in the PubMed. [no cache] 500 found

322) First, MZ twinning would be a fertilization event.

--- ABSTRACT ---

PMID:23735171 DOI:10.1017/S0967199413000257

2015 Zygote (Cambridge, England)

* The timing of monozygotic twinning: a criticism of the common model.

- In the dominant model, monozygotic (MZ) twinning is universally accepted as a post-fertilization event resulting from splitting of the embryo along its first 2 weeks of development. The stage at which splitting occurs determines chorionicity and amnionicity. A short history on how the model was built is presented, stressing the role played by some embryologists, in particular George Corner, in its completion and final success. Strikingly, for more than 60 years no deep criticisms have been raised against the model, which, in virtue of its rational and plausible character, enjoys the status of undisputed truth. At close examination, the embryological support of the model shows some important weak points, particularly when dealing with late splitting. In the author's view, the model not only has contributed to 'suspend' our knowledge on the timing of MZ twinning, but seems indefensible and claims to be substituted. That factor could imply relevant consequences for embryology and bioethics. As an alternative to the model, a new theory to explain the timing of MZ twinning is proposed. It is based on two premises. First, MZ twinning would be a fertilization event. In that case, due to an alteration of the zygote-blastomere transition, the first zygotic division, instead of producing two blastomeres, generates twin zygotes. Second, monochorionicity and monoamnionicity would not depend on embryo splitting, but on fusion of membranes. Some support for this theory can be found in recent embryological advances and also in some explanations of old.

--- ABSTRACT END ---

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[frequency of next (right) word to first]

(1)32 time	(19)5 meaningful	(37)2 5	(55)2 marriage
(2)21 report	(20)4 line	(38)2 6	(56)2 meta-analysis
(3)11 and	(21)3 14	(39)2 72	(57)2 mitochondrial
(4)11 to	(22)3 3	(40)2 application	(58)2 months
(5)10 time,	(23)3 complete	(41)2 approach	(59)2 myocardial
(6)9 year	(24)3 described	(42)2 article	(60)2 postnatal
(7)8 2	(25)3 in	(43)2 attempt	(61)2 presented
(8)8 molar	(26)3 it	(44)2 choice	(62)2 relapse
(9)8 reported	(27)3 order	(45)2 clinical	(63)2 smear
(10)8 step	(28)3 postoperative	(46)2 component	(64)2 stage
(11)8 we	(29)3 record	(47)2 comprehensive	(65)2 step,
(12)7 case	(30)3 sequenced	(48)2 concern	(66)2 test
(13)6 determined	(31)3 the	(49)2 course	(67)2 that
(14)6 group	(32)3 treatment	(50)2 demonstration	(68)2 therapy
(15)6 study	(33)3 two	(51)2 few	(69)2 trimester
(16)5 dose	(34)3 was	(52)2 intentions	(70)2 trimester,
(17)5 evidence	(35)2 null	(53)2 introduction	(71)2 using
(18)5 generation	(36)2 30	(54)2 left

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--- WordNet output for first --- =>初めて, 最初の, 第一の, はじめに, 最初, 第1 Overview of noun first The noun first has 6 senses (first 4 from tagged texts) 1. (9) first, number one -- (the first or highest in an ordering or series; "He wanted to be the first") 2. (5) first, number one, number 1 -- (the first element in a countable series; "the first of the month") 3. (1) beginning, commencement, first, outset, get-go, start, kickoff, starting time, showtime, offset -- (the time at which something is supposed to begin; "they got an early start"; "she knew from the get-go that he was the man for her") 4. (1) first base, first -- (the fielding position of the player on a baseball team who is stationed at first of the bases in the infield (counting counterclockwise from home plate)) 5. first, first-class honours degree -- (an honours degree of the highest class) 6. first gear, first, low gear, low -- (the lowest forward gear ratio in the gear box of a motor vehicle; used to start a car moving) Overview of adj first The adj first has 6 senses (first 5 from tagged texts) 1. (232) first -- (preceding all others in time or space or degree; "the first house on the right"; "the first day of spring"; "his first political race"; "her first baby"; "the first time"; "the first meetings of the new party"; "the first phase of his training") 2. (61) first, 1st -- (indicating the beginning unit in a series) 3. (4) inaugural, initiative, initiatory, first, maiden -- (serving to set in motion; "the magazine's inaugural issue"; "the initiative phase in the negotiations"; "an initiatory step toward a treaty"; "his first (or maiden) speech in Congress"; "the liner's maiden voyage") 4. (4) beginning, first -- (serving to begin; "the beginning canto of the poem"; "the first verse") 5. (3) first, foremost, world-class -- (ranking above all others; "was first in her class"; "the foremost figure among marine artists"; "the top graduate") 6. first -- (highest in pitch or chief among parts or voices or instruments or orchestra sections; "first soprano"; "the first violin section"; "played first horn") Overview of adv first The adv first has 4 senses (first 4 from tagged texts) 1. (58) first, firstly, foremost, first of all, first off -- (before anything else; "first we must consider the garter snake") 2. (40) first, for the first time -- (the initial time; "when Felix first saw a garter snake") 3. (9) first -- (before another in time, space, or importance; "I was here first"; "let's do this job first") 4. (4) foremost, first -- (prominently forward; "he put his best foot foremost") --- WordNet end ---