UVB-protective properties of contact lenses with intended use in photoresponsive eyelid dermatoses.

BACKGROUND: UV-blocking contact lenses were evaluated to determine if they could provide adequate ocular protection during narrowband UVB phototherapy treatment. Theoretical safe exposure durations for the crystalline lens, cornea and conjunctiva were determined. METHODS: A Cary 500 spectrophometer generated transmittance data for six UV-blocking and two non-UV-blocking contact lenses. An IL-1700 radiometer measured the lenses' radiation transmittance within the NB-UVB phototherapy unit. The lenses were exposed to a 1500-mJ/cm(2) dose of radiation from a 308-nm excimer laser to determine if the radiation would alter their protective properties. Theoretical safe exposure durations for eye structures were calculated using previous human and animal study data. RESULTS: All UV-blocking contact lenses showed less than 1E-7 W/cm(2) of radiation transmittance within the narrowband phototherapy unit. The excimer laser did not significantly alter the lenses' UV-blocking capabilities. The safe exposure durations for the cornea and crystalline lens were greater than 11 min with UV-blocking lenses, and that for the unprotected conjunctiva was approximately 11 s. CONCLUSION: Some UV-blocking contact lenses potentially provide sufficient ocular protection during narrowband UVB phototherapy treatment, as the crystalline lens and cornea are adequately protected should a patient open his or her eyes for a short time.

Targeted temperature management in intensive care - Do we let nature take its course?

Should we aim to intervene and control fever in the critically ill patient? The answer is not straightforward and there is certainly no universal agreement on the subject. This article aims to discuss whether we should over-ride nature and disallow it to take it's course, particularly where it appears that this evolutionary response to invading pathogens is actually becoming harmful to the patient. Also discussed here are the physiology of temperature control and the scope of our current understanding of the impact of fever in patients manifesting systemic inflammatory response syndrome (SIRS) and sepsis in ICU, the possible interventions to combat fever (both physical and pharmacological) and the evidence for anti-pyretic drug therapy. The final section examines the potential role of targeted temperature management in the management of sepsis / SIRS in the critically ill.

Orange oil stability in spray dry delivery systems.

The oxidation stability of orange oil flavours encapsulated in carbohydrate based spray dry delivery systems is assessed through accelerated shelf life testing, compatible with the physical state of the delivery system. It is demonstrated here that the oxidative shelf life stability is limited by the diffusion of oxygen through the carbohydrate matrix. Determination of the evolution of orange oil oxidation products with time and correlations with simple but accurate sensory data allows for prediction of absolute shelf life. The oxidative shelf life appears to be dependent only on the number average molecular weight of carbohydrates in the matrix and is not affected by the substitution of small sugars (e.g., maltose for sucrose). A maximum of 2 years shelf life at 25 °C is predicted if sugar dimers are the predominant species in the matrix. The drawback to extended oxidative stability is a low physical stability under humid conditions promoting local softening in the sample. Maltose, having low hygroscopicity, improves the physical stability compared to sucrose. The best compromise between physical (caking) and chemical (oxidation) stability is obtained for carbohydrate compositions with number average molecular weight of 560 g mol(-1) that do not contain sucrose (stability against oxidation: 20 months at 25 °C and stability against humidity: 50% RH at 25 °C).

In situ study of colloid crystallization in constrained geometry.

We visualized in real time electrodeposition-driven colloid crystal growth on patterned conductive surfaces. The electrode was patterned with dielectric ribs and conductive grooves; the groove width was commensurate or incommensurate with a two-dimensional colloid crystal lattice. Electrodeposition was carried out against gravity to decouple sedimentation and electrodeposition of colloid particles. Our experiments reveal the following: (i) Colloid crystal growth occurs under the action of electrohydrodynamic forces, in contrast with colloid assembly under the action of capillary forces. (ii) Confinement of the colloid arrays reduces the size of particle clusters. Small clusters easily undergo structural rearrangements to produce close-packed crystals when the groove width is commensurate or nearly commensurate with the 2D lattice. (iii) Incommensurability between the two-dimensional crystalline lattice and the groove width exceeding ca. 15% leads to the formation of non-close-packed structures and the distortion of colloid arrays.