Impossibility to eliminate observer effect in the assessment of adherence in clinical trials.

PURPOSE: To utilize the Travoprost Dosing Aid (DA) in the assessment of patient medication adherence, while also determining whether or not altering the functionality of the DA in three randomized subject groups can reduce observer effect. METHODS: Forty-five subjects were randomized into three groups: two with monitored DAs and one without monitoring. One group of subjects was given a DA that both monitored drop usage and had visual and audible alarms, while the other monitored group included subjects given a DA that had no alarms but continued to monitor drop usage. The third group was given a DA that had no alarm reminders or dose usage monitoring. Subjects were informed that some monitors would not be functional, in an attempt to reduce observer effect, or the effect of being monitored on subject behavior and adherence. A six-item questionnaire was also utilized to assess how the subjects felt about their adherence and DA use. RESULTS: The overall adherence rates were found to be 78% in the fully functional group (95% confidence interval: 70-88) and 76% in the no alarms group (95% confidence interval: 65-89). No association was seen between questionnaire response and medication adherence. The patients in the DA group without alarms had a significantly higher odds ratio of medication adherence if they reported on the questionnaire that using the DA did affect how much they used their drops. CONCLUSION: Though the use of DA was expected to reveal different rates of adherence depending on the functionality of the DA between groups, patients with a nonfunctioning DA did not have a significant difference in medication adherence compared to those given a fully functional DA. This supports that an observer effect was not reduced despite these interventions, and that the subjects adhered to taking their medications as if they had a functioning DA and were being monitored

Temperature dependent photoluminescence in oxygen ion implanted and rapid thermally annealed ZnO/ZnMgO multiple quantum wells

The authors investigate the effect of oxygen implantation and rapid thermal annealing in ZnO∕ZnMgOmultiple quantum wells using photoluminescence. A blueshift in the photoluminescence is observed in the implanted samples. For a low implantation dose, a significant increase of activation energy and a slight increase of the photoluminescence efficiency are observed. This is attributed to the suppression of the point defect complexes and transformation between defect structures by implantation and subsequent rapid thermal annealing. A high dose of implantation leads to lattice damage and agglomeration of defects leading to large defect clusters, which result to an increase in nonradiative recombination.The authors gratefully acknowledge the Australian Research Council for financial support and Swinburne University of Technology for Strategic Initiative funding. One of the authors X.W. acknowledges partial financial support of the Chinese National Natural Science Foundation 10364004 and the Yunnan Natural Science Foundation 2003E0013M

Characterization of deep level traps responsible for isolation of proton implanted GaAs

Deep level transient spectroscopy was employed to determine the electrical properties of defects induced in metalorganic chemical-vapor deposition grown n-type and p-type GaAs during proton bombardment. Thermal stability of these defects was investigated and correlation with defects responsible for isolation of GaAs by ion bombardment was discussed. The annealing temperature region (220–250 °C) is similar to proton isolated GaAs below the threshold dose for complete isolation. At least four of the five traps observed in n-type GaAs are not simple interstitial-vacancy pairs. For p-type GaAs we have observed an unknown level with apparent energy of ~0.64 eV

Atomic relocation processes in impurity-free disordered p-GaAs epilayers studied by deep level transient spectroscopy

We have used capacitance–voltage and deep level transient spectroscopy techniques to study the relocation of impurities, such as Zn and Cu, in impurity-free disordered (IFD) p-type GaAs. A four-fold increase in the doping concentration is observed after annealing at 925 °C. Two electrically active defects HA (EV+0.39 eV) and HB2 (EV+0.54 eV), which we have attributed to Cu- and Asi/AsGa-related levels, respectively, are observed in the disordered p-GaAs layers. The injection of galliumvacancies causes segregation of Zndopant atoms and Cu towards the surface of IFD samples. The atomic relocation process is critically assessed in terms of the application of IFD to the band gap engineering of doped GaAs-based heterostructures.Two of the authors ~P.N.K.D. and H.H.T.! acknowledge the financial support of the Australian Research Counci

Factors contributing to nonadherence to follow-up appointments in a resident glaucoma clinic versus primary eye care clinic.

PURPOSE: To determine the rate of adherence to follow-up appointment recommendations in a resident glaucoma clinic with no mechanism for reminders, compared to a resident cataract and primary eye care (CPEC) clinic in which telephone reminders were used, and to identify factors that contribute to adherence in each patient group. METHODS: This retrospective cohort study included subjects in the CPEC clinic who received telephone reminders and those in the glaucoma clinic who did not. Each sample was selected to have a similar proportion of follow-up recommendations for 1, 3, and 6 months. Subjects were considered adherent if they returned within a specified timeframe. RESULTS: A total of 144 subjects from the glaucoma clinic and 151 subjects from the CPEC clinic were included. There was no significant difference between follow-up adherence rates of patients who received telephone reminders and those who did not (odds ratio [OR] =1.35, 95% confidence interval [CI] 0.79-2.32, P=0.28). Patients who were on more than two ocular medications were more likely to return for follow-up (OR=3.11, 95% CI 1.53-6.35, P=0.0018). Subjects between the ages 50 and 80 years were more likely to be adherent compared to their younger and older peers (P=0.02). CONCLUSION: The follow-up adherence of patients in a CPEC clinic who received telephone reminders was similar to patients in a glaucoma clinic who did not receive any intervention to increase their adherence. Younger (⩽50 years old) and elderly (⩾80 years old) subjects, as well as patients using less than two glaucoma medications, were less likely to adhere to their follow-up appointments

Three-dimensional electronic spectroscopy of excitons in asymmetric double quantum wells

We demonstrate three-dimensional (3D) electronic spectroscopy of excitons in a double quantum well system using a three-dimensional phase retrieval algorithm to obtain the phase information that is lost in the measurement of intensities. By extending the analysis of two-dimensional spectroscopy to three dimensions, contributions from different quantum mechanical pathways can be further separated allowing greater insight into the mechanisms responsible for the observed peaks. By examining different slices of the complete three-dimensional spectrum, not only can the relative amplitudes be determined, but the peak shapes can also be analysed to reveal further details of the interactions with the environment and inhomogeneous broadening. We apply this technique to study the coupling between two coupled quantum wells, 5.7 nm and 8 nm wide, separated by a 4 nm barrier. Coupling between the heavy-hole excitons of each well results in a circular cross-peak indicating no correlation of the inhomogeneous broadening. An additional cross-peak is isolated in the 3D spectrum which is elongated in the diagonal direction indicating correlated inhomogeneous broadening. This is attributed to coupling of the excitons involving the two delocalised light-hole states and the electron state localised on the wide well. The attribution of this peak and the analysis of the peak shapes is supported by numerical simulations of the electron and hole wavefunctions and the three-dimensional spectrum based on a density matrix approach. An additional benefit of extending the phase retrieval algorithm from two to three dimensions is that it becomes substantially more reliable and less susceptible to noise as a result of the more extensive use of a priori information.The authors gratefully acknowledge the Australian Research Council and Australian National Fabrication Facility for financial support

Impurity-free disordering mechanisms in GaAs-based structures using doped spin-on silica layers

We have used photoluminescence,deep level transient spectroscopy and x-ray photoelectron spectroscopy to investigate the mechanisms of impurity-free disordering in GaAs-based structures using doped spin-on silica layers. We demonstrate that VGa is efficiently converted into arsenic-antisite, AsGa, related defects (EL2-type defects) when the GaAs layer is under compressive stress. We propose that the efficient formation of EL2-type defects reduces the efficiency of impurity-free interdiffusion of GaAs/AlGaAs quantum wells.Two of the authors (P.N.K.D. and H.H.T.) gratefully acknowledge financial support by the Australian Research Council

Engineering semiconductor nanowires for photodetection: From visible to terahertz

III-V semiconductor nanowires combine the properties of III-V materials with the unique advantages of the nanowire geometry, allowing efficient room temperature photodetection across a wide range of photon energies, from a few eV down to meV. For example, due to their nanoscale size, these show great promise as sub-wavelength terahertz (THz) detectors for near-field imaging or detecting elements within a highly integrated on-chip THz spectrometer. We discuss recent advances in engineering a number of sensitive photonic devices based on III-V nanowires, including InAs nanowires with tunable photoresponse, THz polarisers and THz detectors.The authors gratefully acknowledge financial support from the European Research Council (ERC Starting Grant ACrossWire), the Engineering and Physical Sciences Research Council (UK), the Australian Research Council, and the Australian National Fabrication Facility (ANFF). J. A. Alexander-Webber and H. J. Joyce especially thank the Royal Commission for the Exhibition of 1851 for their research fellowships

Diabetes eye screening in urban settings serving minority populations: detection of diabetic retinopathy and other ocular findings using telemedicine.

IMPORTANCE: The use of a nonmydriatic camera for retinal imaging combined with the remote evaluation of images at a telemedicine reading center has been advanced as a strategy for diabetic retinopathy (DR) screening, particularly among patients with diabetes mellitus from ethnic/racial minority populations with low utilization of eye care. OBJECTIVE: To examine the rate and types of DR identified through a telemedicine screening program using a nonmydriatic camera, as well as the rate of other ocular findings. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional study (Innovative Network for Sight [INSIGHT]) was conducted at 4 urban clinic or pharmacy settings in the United States serving predominantly ethnic/racial minority and uninsured persons with diabetes. Participants included persons aged 18 years or older who had type 1 or 2 diabetes mellitus and presented to the community-based settings. MAIN OUTCOMES AND MEASURES: The percentage of DR detection, including type of DR, and the percentage of detection of other ocular findings. RESULTS: A total of 1894 persons participated in the INSIGHT screening program across sites, with 21.7% having DR in at least 1 eye. The most common type of DR was background DR, which was present in 94.1% of all participants with DR. Almost half (44.2%) of the sample screened had ocular findings other than DR; 30.7% of the other ocular findings were cataract. CONCLUSIONS AND RELEVANCE: In a DR telemedicine screening program in urban clinic or pharmacy settings in the United States serving predominantly ethnic/racial minority populations, DR was identified on screening in approximately 1 in 5 persons with diabetes. The vast majority of DR was background, indicating high public health potential for intervention in the earliest phases of DR when treatment can prevent vision loss. Other ocular conditions were detected at a high rate, a collateral benefit of DR screening programs that may be underappreciated