ABSTRACT
The disordered-molecular-alloy phase (DMA) of ammonia hydrates [J. S. Loveday and R. J. Nelmes, Phys. Rev. Lett. 83, 4329 (1999)] is unique in that it has substitutional disorder of ammonia and water over the molecular sites of a body centred cubic lattice. Whilst this structure has been observed in ammonia di- and mono-hydrate compositions, it has not been conclusively observed in the ammonia hemihydrate system. This work presents investigations of the structural behaviour of ammonia hemihydrate as a function of P and T. The indications of earlier studies [Ma et al. RSC Adv. 2, 4290 (2012)] that the DMA structure could be produced by compression of ammonia hemihydrate above 20 GPa at ambient temperature are confirmed. In addition, the DMA structure was found to form reversibly both from the melt, and on warming of ammonia hemihydrate phase-II, in the pressure range between 4 and 8 GPa. The route used to make the DMA structure from ammonia mono- and di-hydrates--compression at 170 K to 6 GPa followed by warming to ambient temperature--was found not to produce the DMA structure for ammonia hemihydrate. These results provide the first strong evidence that DMA is a thermodynamically stable form. A high-pressure phase diagram for ammonia hemihydrate is proposed which has importance for planetary modelling.
ABSTRACT
Anterior segment and external ocular manifestations of some infectious diseases which are particularly important to patients of the pediatric age group are discussed. A brief review of the various systemic diseases is given along with the ocular findings. Approaches to diagnosis, therapy, and management of both the systemic and ocular components of the illnesses are included.
Subject(s)
Anterior Chamber , Infections/complications , Adenovirus Infections, Human/diagnosis , Bacterial Infections/diagnosis , Child , Eye Diseases/etiology , Female , Herpesviridae Infections/complications , Humans , Ophthalmia Neonatorum/etiology , Poxviridae Infections/diagnosis , Pregnancy , Pregnancy Complications, Infectious , Respirovirus Infections/diagnosis , Rubella , Streptococcal Infections/therapy , Syphilis, Congenital/complicationsABSTRACT
The actions and indications of cypcloplegics are presented along with recommended dosages and uses for clinical measures of refractive error.
Subject(s)
Ciliary Body/drug effects , Mydriatics , Refractive Errors/diagnosis , Adult , Amblyopia/drug therapy , Atropine/pharmacology , Atropine/therapeutic use , Child , Child, Preschool , Drug Administration Schedule , Humans , Infant , Mydriatics/pharmacology , Refractive Errors/complications , Strabismus/complicationsSubject(s)
Cataract/rehabilitation , Contact Lenses , Iris , Adult , Atrophy/etiology , Esthetics , Eye Color , Female , Humans , Uveal Diseases/rehabilitationABSTRACT
Forty-one patients were treated with soft bandage lenses for various types of corneal pathology. These patients have been monitored over a two-year period. Comfort was consistently achieved with cases of bullous and exposure keratopathies. It was found that the Warner-Lambert Softcon lens gave better protection in patients with VII nerve palsies than the Bausch & Lomb SOFLENS contact lens. However, little difference was noted between the two types of lenses when treating other corneal diseases. It was also found that topical medications, with the exception of steroids, caused no complications.
