ABSTRACT
OBJECTIVE: To compare the efficacy and safety of negatively-charged polystyrene microspheres (NCM)with controls (saline soaks) in the treatment of hard-to-heal wounds of various aetiologies. METHOD: Patients with one or more hard-to-heal wounds, defined as refractory to healing for at least 4 weeks, or those with exposed bone, tendon or ligament, were eligible for inclusion and were randomised to either NCM (PolyHeal; MediWound Ltd.) or controls, both applied twice daily for 4 weeks. Patients were monitored bi-weekly for an additional 8 weeks, while treated by standard wound care, at the investigators' discretion, and were re-evaluated 2 years after inclusion. The primary endpoint was defined as coverage of> 75% of the wound area by light-red granulation tissue after 4 weeks of treatment. RESULTS: Fifty-eight patients completed the study, 32 in the NCM group and 26 in the control group. The two most common wound types were those with primary etiologies of venous insufficiency and postoperative/post trauma. In the NCM group 47% of patients achieved > 75% light red granulation tissue after 4 weeks compared with 15% of patients in the control group (p=O.O I). The mean wound surface area in the NCM group was reduced by 39.0% after 4 weeks compared with 14.9% in the control group (p=0.02).The achievement of> 75% light red granulation tissue and reduction of mean wound surface area was also observed in the two main sub-groups (venous insufficiency and postoperative/post trauma), although it was not statistically significant, possibly due to the small sample size in each sub-group. CONCLUSION: This study demonstrates that compared to control treatment, NCM treatment of hard to-heal and chronic wounds improves formation of healthy granulation tissue and reduces wound size thus in fact 'kick-starting' the healing process and 'dechronifying' chronic wounds.
Subject(s)
Anions/therapeutic use , Granulation Tissue/growth & development , Microspheres , Skin Ulcer/therapy , Wound Healing , Adult , Aged , Chronic Disease , Double-Blind Method , Female , Humans , Male , Middle Aged , Polystyrenes , Prospective Studies , Saline Solution, Hypertonic , Static Electricity , Treatment OutcomeABSTRACT
The characteristic matrix method is used to compute the electric field distribution in a multilayer. The use of optically inhomogeneous films is suggested to lessen discontinuity in the material properties and in the absorption distribution at interfaces between the high-index and the low-index layers, thereby enhancing the laser damage threshold.
ABSTRACT
A confocal mirror assembly is used to measure radiant reflectances in excess of 0.99 with high precision. The mirrors can be either plano or curved with a few diopters of power, and the angle of incidence can vary from 5 degrees to 70 degrees . Multilayer dielectric reflectors consisting of alternate layers of tantalum pentoxide and silica were prepared by evaporation in a vacuum. A maximum reflectance of 0.9996 +/- 0.0002 was measured at 520 nm.
ABSTRACT
We measured the refractive index of layers of hafnium dioxide that were prepared by evaporation in a vacuum. It is transparent to wavelengths as short as 230 nm. Its refractive index at 300 nm was as high as 2.10 or as low as 1.90, depending upon the conditions of evaporation. Tests at Los Alamos Scientific Laboratory indicate that its laser damage threshold is approximately 2 J/cm(2) at a wavelength of 355 nm. Multilayer dielectric mirrors were prepared using hafnium dioxide and silicon dioxide. The radiant reflectance exceeded 99% at a wavelength of 320 nm.
ABSTRACT
Residual absorption and scattering are loss mechanisms that degrade the performance of all thin films optical devices. By analogy to residual absorption, expressions are derived to evaluate losses due to surface and bulk scattering in dielectric multilayers. Based on these, proposals are made to improve the traditional performances of some basic filters. It is shown how, by means of index inhomogeneity, surface scattering is expected to be reduced considerably.