Time-Resolved Changes in Dielectric Constant of Metal Halide Perovskites under Illumination.

Despite their impressive performance as a solar absorber, much remains unknown on the fundamental properties of metal halide perovskites (MHPs). Their polar nature in particular is an intense area of study, and the relative permittivity (εr) is a parameter widely used to quantify polarization over a range of different time scales. In this report, we have exploited frequency-dependent time-resolved microwave conductivity (TRMC) to study how εr values of a range of MHPs change as a function of time, upon optical illumination. Further characterization of charge carriers and polarizability are conducted by femtosecond transient absorption and stimulated Raman spectroscopy. We find that changes in εr are roughly proportional to photogenerated carrier density but decay with a shorter time constant than conductance, suggesting that the presence of charge carriers alone does not determine polarization.

Impact of Moisture on Mobility in Methylammonium Lead Iodide and Formamidinium Lead Iodide.

The greatest remaining barrier to the commercialization of perovskite solar cells is their instability to ambient environmental conditions. While most studies of the electronic stability of perovskites employ finished devices, we here exploit the contactless characterization technique time-resolved microwave conductivity to probe electronic properties in the absence of encapsulation and interface effects. By tracking the mobility of charge carriers in two archetypal perovskite compounds, methylammonium lead iodide (MAPbI3) and formamidinium lead iodide (FAPbI3) under various conditions, we are able to make decisive statements about the role of water in the electronic performance of perovskites. Overall, we observe a strong negative correlation between hydration and mobility in MAPbI3, but not in FAPbI3. We anticipate that the data presented herein will serve as a valuable resource in future stability studies in perovskite solar cells and, ultimately, lead to more stable devices.

Intraocular infections in the neonatal intensive care unit.

BACKGROUND: The purpose of this study was to report on the incidence and treatment outcomes of endogenous endophthalmitis among newborns in the neonatal intensive care unit (NICU) of a single medical center. METHODS: This was a noncomparative, retrospective case series of endogenous endophthalmitis among infants at the Jackson Memorial Hospital NICU treated between March 1, 2002 and March 1, 2007. RESULTS: Of 4323 infants admitted to the NICU, seven eyes of six (0.139%) infants (two males, four females) were diagnosed with endophthalmitis during the study period. Four patients were born prematurely with a mean gestational age of 27.5 weeks and a mean birth weight of 1153 g. Retinopathy of prematurity was reported in two of the six patients. Mean follow-up was 3.5 years. The diagnosis was confirmed by positive cultures or polymerase chain reaction testing at a median age of 34 postnatal days. Positive cultures included Candida albicans (n = 4), Pseudomonas aeruginosa (n = 1), and Herpes simplex type 2 (n = 1). All patients received systemic treatment and five received adjunctive ophthalmic interventions, including intravitreal antibiotics in five eyes of four patients and vitrectomy with pars plana lensectomy in three eyes. One patient underwent primary enucleation and another had delayed evisceration. In the remaining five eyes, there was a normal appearing posterior segment and normal intraocular pressures at last follow-up. CONCLUSION: Endogenous endophthalmitis is a rare complication in infants in the NICU, but may occur in patients with candidemia, bacteremia, retinopathy of prematurity, and low birth weight. Despite early and appropriate treatment, involved eyes may have poor outcomes.

Participant perceptions of a mindful movement program for older women with breast cancer: focus group results.

BACKGROUND: Little attention has been directed to the longer-term survivorship phase for older breast cancer survivors (BCSs) who often continue to struggle with late and long-term adverse effects of treatment including lower physical functioning, fear of recurrence, stress and anxiety, neuropathies, and pain. Creative and accessible strategies are needed that offer support to this population of cancer survivors. OBJECTIVE: The purpose of this study was to examine participant perceptions of the effects of a Mindful Movement Program intervention on quality of life and mindfulness through focus groups. This was part of a pilot feasibility study testing the intervention with older women at more than 1 year after treatment for breast cancer. METHODS: Eight to 9 weeks after completion of 12 weekly, 2-hour mindful movement sessions, focus groups were held with 3 experimental group cohorts of participants who had attended on average 10.4 classes. Focus group interviews were recorded, transcribed verbatim, and analyzed using qualitative techniques for recurrent themes. RESULTS: Four themes emerged from the direct quotes of the participants: freedom, rediscovering, body sense in moving, and in the moment. Participants also contributed opinions about program delivery. CONCLUSIONS: Participants described how the Mindful Movement Program experience affected their lives. Their feedback indicated that the intervention yielded positive results and was feasible for a variety of older BCSs. IMPLICATIONS FOR PRACTICE: Research with a wider group of participants is needed. Preliminary indications are that mindful movement may offer an acceptable strategy for increasing activity and decreasing stress among older BCSs.

Retinal detachment despite aggressive management of aggressive posterior retinopathy of prematurity.

Posterior retinopathy of prematurity (ROP) is unusual in its atypical features and its aggressive, rapidly progressive course. It is more difficult to recognize and to treat, with many of these eyes progressing to retinal detachment despite multiple treatments with laser or cryotherapy. The authors present a case of aggressive posterior ROP refractory to multiple laser treatment. This patient was successfully treated with intravitreal bevacizumab, but required repeat treatment 4 months later. The second injection with bevacizumab was followed by progression to retinal detachment requiring surgery. The patient remains stable after surgery.

The Golden Hour: care of the LBW infant during the first hour of life one unit's experience.

Care practices during the first hour of life, the Golden Hour, can have a significant impact on outcomes of low birth weight infants. Although the latest edition of the Neonatal Resuscitation Program added guidelines for preterm infants, additional care is often indicated. Complications that could potentially be impacted by care in the first hour of life include thermoregulation, intraventricular hemorrhage, chronic lung disease, and retinopathy of prematurity. Our unit has implemented and revised a Golden Hour evidence-based care process that includes the use of realistic videotaped simulations, followed by team debriefing sessions. Early results of the revised process show reductions in the targeted complications.

Off-label use of intravitreal bevacizumab (Avastin) for salvage treatment in progressive threshold retinopathy of prematurity.

PURPOSE: To report the short term anatomic response of intravitreal bevacizumab (Avastin, Genentech) as salvage treatment in progressive retinopathy of prematurity (ROP) in a small series of patients. METHODS: The study included five eyes of three patients with progressive ROP despite peripheral laser ablation. Patients received intravitreal injections of bevacizumab (Avastin, Genentech). RetCam (Clarity Medical Systems, Inc., Pleasanton, CA) photography and ultrasonography were used to document effect. RESULTS: Three patients were transferred to the Bascom Palmer Eye Institute/Jackson Memorial Hospital for management of progressive ROP despite laser therapy at an outside facility. RetCam fundus photography and ultrasonography were used to document all cases. After informed consent was obtained from the parents, the patients received off-label intravitreal bevacizumab as salvage treatment. Repeat intravitreal injections of bevacizumab were utilized in several cases. The ROP stabilized allowing laser supplementation. There was varying development of tractional retinal detachments in several of the eyes but the ROP component quieted in all cases. CONCLUSIONS: Off-label use of bevacizumab appears to be useful as a salvage treatment for ROP when laser treatment is precluded. It improves dilation, quiets the disease when visibility is difficult, and temporizes the disease until laser can be supplemented.

Anterior segment ischemia following laser therapy for threshold retinopathy of prematurity.

PURPOSE: To report on the clinical characteristics and outcomes of premature infants developing signs of anterior segment ischemia after laser therapy for threshold retinopathy of prematurity treated or referred to a university institution. METHODS: A retrospective review of the medical records of premature infants with a primary diagnosis of retinopathy of prematurity undergoing laser therapy for threshold disease from January 1, 2001, to June 1, 2006. RESULTS: A total of 10 eyes in six patients were identified that developed signs of anterior segment ischemia for which a 1-year follow-up was available. The mean gestational age of patients developing anterior segment ischemia was 26.1 weeks. The mean weight was 855 g. The mean gestational age when laser photoablation was initiated was 36.3 weeks. All infants developing ischemia were treated with intermittent dense laser pattern using the diode laser. No infants treated thus far with confluent laser pattern have developed anterior segment ischemia. CONCLUSION: Confluent laser pattern in our experience does not predispose to anterior segment ischemia. Anterior segment ischemia primarily affects premature infants less than 28 weeks gestational age with low birthweights, less than 1,075 g. Intravitreal steroids at the time of pars plana vitrectomy and lensectomy may be beneficial in selected patients.