An average of 65 percent of children aged between 8 and 11 have their own smartphone in the U.K. according to a survey by Internet Matters. That survey also found that the majority of parents would like a minimum age for smartphone ownership in the U.K. to be set at age 10. However, some kids are using smartphones from a very young age. One study by the American Academy of Pediatrics that focused on children in an urban, low-income, minority community suggested that almost all children (96.6 percent) use mobile devices and that 75 percent have their own mobile device by the age of four.
A cyclic acetal is an acetal in which the acetal carbon and one or both oxygen atoms are members of a ring. An acetal is a compound that contains two ether groups on the same carbon atom. If the two OH groups are part of a 1,2- or a 1,3-diol, the product is a cyclic acetal. The video below describes how a cyclic acetal is formed from a diol. The purple #color(purple)(O)# atom in the hemiacetal intermediate is held close to the hemiacetal carbon, so the intramolecular ring-closing reaction is fast.
proposed ACE catalytic mechanism. Angiotensin-converting enzyme (EC 3.4.15.1), or ACE, is a central component of the renin-angiotensin system (RAS), which controls blood pressure by regulating the volume of fluids in the body. It converts the hormone angiotensin I to the active vasoconstrictor angiotensin II.