In this paper, we explain the persistence of solid-solution states in phase-separating LiFePO<sub>4</sub> nanoparticles cycled at low-to-moderate C-rates, thereby resolving an important paradox in the Li-ion battery community.
Analogous to electron waves in a crystal, light waves in a three-dimensionally periodic dielectric structure should be described by band theory. The concept of photonic band structure 1 is gaining rapid 2−5 acceptance. The concepts of reciprocal space, Brillouin zones, dispersion relations, Block wave functions, van Hove singularities, etc. are now being applied to optical waves.
Acylation resins in a new monolithic format have been prepared by the functionalization of polyethylene-encased porous poly(chloromethylstyrene-co-divinylbenzene) disks. These disks have been obtained from a monolithic rod prepared by polymerization in a cylindrical glass mold, then cut into a disk format. A free radical azo initiator 4,4'-azobis(4-cyanovaleric acid) attached to available chloromethyl functionalities at the surface of the pores was used to initiate graft polymerization of 4-acetoxystyrene or chloromethylstyrene from the surface. Addition of a small percentage of divinylbenzene to the polymerization mixture leads to the formation of a layer of swellable reactive polymer gel at the surface of the macropores. This both prevents the undesirable increase in flow resistance through the monolith and improves the yield of grafting. The final reaction steps involve formation of an active phenolic moiety grafted to the disks and its reaction with acid anhydride. The use of grafted disks as acylating resin to transform various amines to amides in flow-through operations is demonstrated in a variety of solvents including alcohols. The acylation ability of the depleted disks can easily be recovered, and the disks can be reused many times.
Summary The aim of the current study was to assess the development and stability of sleep problems from childhood to late adolescence. This was a longitudinal cohort study of 2026 children, who completed three comprehensive health surveys, at age 7–9, 11–13 and 16–19 years. Data on difficulties with initiating and/or maintaining sleep ( DIMS : assessed using a single item) and time in bed ( TIB ) were collected at all three waves, while insomnia assessed in line with the DSM ‐5 criteria and sleep duration were also assessed in the last wave. Negative binomial regression analyses were used to examine prospective associations. Sleep problems in 7–9‐year‐old children were found to persist into late adolescence for approximately one‐third of the participants, both with regard to DIMS and short TIB . Children having chronic DIMS at the first two waves had nearly twice the risk of fulfilling the DSM ‐5 criteria later for insomnia in late adolescence [adjusted relative risk RR : 1.91]. Short TIB at age 11–13 was also associated with increased risk of subsequent short sleep duration (adjusted RR : 1.32) and TIB (adjusted RR : 1.40). These findings have important implications for practitioners and families. Although the majority of children will outgrow their problems once they reach late adolescence, the results also demonstrate that sleep problems are likely to become chronic for one in every third child with a sleep problem early in life. Given the many negative consequences of insomnia in adulthood, these findings call for increased awareness of childhood sleep problems as a public health concern.
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Providing extensive care for a grandchild was associated with elevated levels of depression. Physicians should be alert to family role changes and symptoms of depression in their older patients.
