Author Correction: A nano-mechanical instability as primary contribution to rolling resistance.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A nano-mechanical instability as primary contribution to rolling resistance.

Rolling resistance ranks among the top ten automobile megatrends, because it is directly linked to fuel efficiency and emissions reduction. The mechanisms controlling this phenomenon are hidden deeply inside the complexity of tire tread materials and do elude direct experimental observation. Here we use atomistic molecular modelling to identify a novel nano-mechanical mechanism for dissipative loss in silica filled elastomers when the latter are subjected to dynamic strain. The force-vs-particle separation curve of a single silica particle-to-silica particle contact, embedded inside a polyisoprene rubber matrix, is obtained, while the contact is opened and closed by a cyclic force. We confirm the occurrence of spontaneous relative displacements ('jolts') of the filler particles. These jolts give rise to energy dissipation in addition to the usual viscous loss in the polymer matrix. As the temperature is increased the new loss mechanism becomes dominant. This has important technical implications for the control and reduction of tire rolling resistance as well as for many other elastomer composite applications involving dynamic loading.

Boston type 1 keratoprosthesis for failed keratoplasty.

The purpose of this study was to evaluate the outcomes of the Boston type 1 keratoprosthesis (Kpro-1) in eyes with failed keratoplasty. A retrospective review was performed of every patient treated with a Kpro-1 at a tertiary eye care center between January 1, 2008 and July 1, 2013. Eyes with a failed keratoplasty originally performed for corneal edema, trauma, or keratoconus were included in the statistical analysis. The main outcome measures were visual outcome, prosthesis retention, and postoperative complications. Twenty-four eyes met the inclusion criteria, including 13 eyes with corneal edema, 8 eyes with trauma, and 3 eyes with keratoconus. After a mean follow-up period of 28.9 months (range 7-63 months), the median best corrected visual acuity (BCVA) was 20/125. The BCVA was ≥ 20/40 in 4 (16.7 %) eyes, ≥ 20/70 in 9 (37.5 %) eyes, and ≥ 20/200 in 14 (58.3 %) eyes. Overall, the postoperative BCVA improved in 17 (70.9 %) eyes, was unchanged in 3 (12.5 %) eyes, and was worse in 4 (16.7 %) eyes. The initial Kpro-1 was retained in 22 (91.7 %) eyes, and was successfully repeated in the other 2 eyes. One or more serious prosthesis- or sight-threatening complications occurred in 8 (33.3 %) eyes. These included 1 case of wound dehiscence leading to prosthesis extrusion, 1 case of fungal keratitis leading to prosthesis extrusion, 4 cases of endophthalmitis, and 5 retinal detachments. The Boston Kpro-1 is associated with an excellent prognosis for prosthesis retention and satisfactory visual improvement in eyes with previous failed keratoplasty.

Boston type 1 keratoprosthesis for chemical and thermal injury.

PURPOSE: To evaluate the outcome of the Boston type 1 keratoprosthesis (Kpro-1) in eyes with failed interventions for chemical and thermal injury. METHODS: A retrospective review was performed of every eye with chemical or thermal injury that was treated with a Kpro-1 at a tertiary eye care center between January 1, 2008 and July 1, 2013. The main outcome measures were visual outcome, prosthesis retention, and postoperative complications. RESULTS: Nine eyes met the inclusion criteria, including 7 eyes with alkali burns, 1 eye with an acid burn, and 1 eye with a thermal burn. After a mean follow-up of 40.7 months (range, 29-60 months), the median best-corrected visual acuity was 20/60 (range, 20/15 to no light perception). One eye was ≥20/20, 3 eyes were ≥20/40, and 6 eyes were ≥20/70. The initial Kpro-1 prosthesis was retained in 7 (77.7%) eyes and successfully replaced in the other 2 eyes. One or more serious complications occurred in 6 (66.7%) eyes. These included 2 cases of sterile corneal ulceration with prosthesis extrusion, 2 cases of microbial keratitis (1 bacterial and 1 fungal), 2 cases of bacterial endophthalmitis, and 2 cases of retinal detachments. These complications contributed to visual outcomes of hand motions in 2 eyes and no light perception in 1 eye. CONCLUSIONS: The Boston Kpro-1 is associated with highly satisfactory visual outcomes and prosthesis retention in most cases of severe chemical or thermal injury. Serious complications are common and may compromise the final outcome.

Candida krusei fungemia in an immunocompromised patient.

Candida krusei is an emerging fungal pathogen found primarily in immunocompromised patients. Intrinsic resistance to fluconazole and decreasing susceptibility to other anti-fungal agents are problematic. When colonization occurs, dissemination may follow rapidly. We present a case of a patient with acute lymphoblastic leukemia who, despite being treated prophylactically with fluconazole, developed disseminated C. krusei.