High-resolution cathodoluminescence hyperspectral imaging of nitride nanostructures

Hyperspectral cathodoluminescence imaging provides spectrally and spatially resolved information on luminescent materials within a single dataset. Pushing the technique toward its ultimate nanoscale spatial limit, while at the same time spectrally dispersing the collected light before detection, increases the challenge of generating low-noise images. This article describes aspects of the instrumentation, and in particular data treatment methods, which address this problem. The methods are demonstrated by applying them to the analysis of nanoscale defect features and fabricated nanostructures in III-nitride-based materials

Safety and Feasibility of Carboplatin and Paclitaxel followed by Fluoropyrimidine Analogs and Radiation as Adjuvant Therapy for Gastric Cancer

Background: Adjuvant 5-fluorouracil (5FU)-based chemo-radiotherapy is currently considered a standard of care for the treatment of gastric cancer. The impact of 5FU-based adjuvant therapy on the rate of distant recurrence has been modest. In order to improve the systemic effects of adjuvant therapy, we have been treating patients with resected gastric cancer with carboplatin and paclitaxel followed by fluoropyrimidine analogue and radiation. Methods: We report on the outcomes of 21 consecutive gastric cancer patients treated off protocol with adjuvant carboplatin (area under the curve 5 mg/ml × min) and paclitaxel (175–200 mg/m2) every 3 weeks, followed by concurrent pyrimidine analogs (either capecitabine 1,600–2,000 mg/m2/day in 17 patients, or 5FU 200 mg/m2/day in 4 patients) and radiation (45–50.4 Gy). Patients received a total of 4–6 cycles of carboplatin and paclitaxel. Results: The median age at diagnosis was 60 years. Sixteen patients had stage 3 disease and 7 of them had positive surgical margins (6 with R1 and 1 with R2 resection), 3 patients were stage 2, and 2 patients were stage 1 (all had R0 resection). All patients had D1/D2 (4 had D2 and 17 had D1) lymph node dissection. The incidence of grade 3 or higher overall, hematologic, or gastrointestinal toxicity in the patients receiving carboplatin and paclitaxel was 57, 48 and 10%, respectively. No treatment-related deaths were observed. After adjuvant treatment 15 patients developed recurrent disease, 10 of whom had distant metastases. The median recurrence-free survival (RFS) was 12.3 months. The median overall survival (OS) was 16.0 months. Patients with R0 resection had significantly longer OS than did those with positive surgical margins (log-rank p = 0.0060). Median OS for the R0 resection group was 28.8 months. Conclusions: Carboplatin and paclitaxel added to radiation plus fluoropyrimidine analogs is a well-tolerated regimen in the adjuvant setting. The activity of this regimen in this relatively high-risk group of gastric cancer patients is of interest for future development

CA19-9 as a predictor of tumor response and survival in patients with advanced pancreatic cancer treated with gemcitabine based chemotherapy

The aim of this study was to determine the predictive role of pretreatment carbohydrate antigen 19-9 (CA19-9) measurement and its change after one cycle of gemcitabine-based therapy for response, time to progression (TTP) and overall survival (OS).Analyses were derived from three consecutive gemcitabine-containing phase II clinical trials between 1997 and 2004.A total of 111 patients with pancreas cancer was studied. Baseline CA19-9 concentrations were dichotomized near the median. Lower baseline CA19-9 levels were positively associated with OS (median 9.1 vs 6.1 months, P  = 0.0057) and TTP (median 6.4 vs 4.2 months, P  = 0.0044).The covariate adjusted hazard ratio (HR) for progression among patients with baseline CA19-9 ≥ 1000 ng/mL was HR = 1.94 (95% CI 1.24–3.02), with P  = 0.0035. The covariate adjusted risk of death among patients with baseline CA19-9 ≥ 1000 ng/ml was similarly elevated: HR = 1.90 (95% CI 1.23–2.94), with P  = 0.0039. Change in CA19-9 levels from baseline to the end of treatment cycle 1 did not predict objective response ( P  = 0.75). There was somewhat longer OS (median 8.7 vs 7.1 months) and TTP (median 7.1 vs 5.4 months) in patients with ≥50% reduction in serum CA19-9 concentrations, but this was not statistically significant ( P  = 0.74 and 0.81, respectively).Baseline CA19-9 levels may predict survival in patients with advanced pancreas cancer. The change in CA19-9 levels determined within 1 month of the initiation of therapy did not predict treatment outcome.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79310/1/j.1743-7563.2010.01290.x.pd

User-Centered Design of A Novel Risk Prediction Behavior Change Tool Augmented With an Artificial Intelligence Engine (MyDiabetesIQ):A Sociotechnical Systems Approach

BACKGROUND: Diabetes and its complications account for 10% of annual health care spending in the United Kingdom. Digital health care interventions (DHIs) can provide scalable care, fostering diabetes self-management and reducing the risk of complications. Tailorability (providing personalized interventions) and usability are key to DHI engagement/effectiveness. User-centered design of DHIs (aligning features to end users’ needs) can generate more usable interventions, avoiding unintended consequences and improving user engagement. OBJECTIVE: MyDiabetesIQ (MDIQ) is an artificial intelligence engine intended to predict users’ diabetes complications risk. It will underpin a user interface in which users will alter lifestyle parameters to see the impact on their future risks. MDIQ will link to an existing DHI, My Diabetes My Way (MDMW). We describe the user-centered design of the user interface of MDIQ as informed by human factors engineering. METHODS: Current users of MDMW were invited to take part in focus groups to gather their insights about users being shown their likelihood of developing diabetes-related complications and any risks they perceived from using MDIQ. Findings from focus groups informed the development of a prototype MDIQ interface, which was then user-tested through the “think aloud” method, in which users speak aloud about their thoughts/impressions while performing prescribed tasks. Focus group and think aloud transcripts were analyzed thematically, using a combination of inductive and deductive analysis. For think aloud data, a sociotechnical model was used as a framework for thematic analysis. RESULTS: Focus group participants (n=8) felt that some users could become anxious when shown their future complications risks. They highlighted the importance of easy navigation, jargon avoidance, and the use of positive/encouraging language. User testing of the prototype site through think aloud sessions (n=7) highlighted several usability issues. Issues included confusing visual cues and confusion over whether user-updated information fed back to health care teams. Some issues could be compounded for users with limited digital skills. Results from the focus groups and think aloud workshops were used in the development of a live MDIQ platform. CONCLUSIONS: Acting on the input of end users at each iterative stage of a digital tool’s development can help to prioritize users throughout the design process, ensuring the alignment of DHI features with user needs. The use of the sociotechnical framework encouraged the consideration of interactions between different sociotechnical dimensions in finding solutions to issues, for example, avoiding the exclusion of users with limited digital skills. Based on user feedback, the tool could scaffold good goal setting, allowing users to balance their palatable future complications risk against acceptable lifestyle changes. Optimal control of diabetes relies heavily on self-management. Tools such as MDMW/ MDIQ can offer personalized support for self-management alongside access to users’ electronic health records, potentially helping to delay or reduce long-term complications, thereby providing significant reductions in health care costs

Temporal and Spatial Patterns of Serologic Responses to Plasmodium Falciparum Antigens in a Region of Declining Malaria Transmission in Southern Zambia

Background: Critical to sustaining progress in malaria control is comprehensive surveillance to identify outbreaks and prevent resurgence. Serologic responses to Plasmodium falciparum antigens can serve as a marker of recent transmission and serosurveillance may be feasible on a large scale. Methods. Satellite images were used to construct a sampling frame for the random selection of households enrolled in prospective longitudinal and cross-sectional surveys in two study areas in Southern Province, Zambia, one in 2007 and the other in 2008 and 2009. Blood was collected and stored as dried spots from participating household members. A malaria rapid diagnostic test (RDT) was used to diagnose malaria. An enzyme immunoassay (EIA) was used to detect IgG antibodies to asexual stage P. falciparum whole parasite lysate using serum eluted from dried blood spots. The expected mean annual increase in optical density (OD) value for individuals with a documented prior history of recent malaria was determined using mixed models. SatScan was used to determine the spatial clustering of households with individuals with serological evidence of recent malaria, and these households were plotted on a malaria risk map. Results: RDT positivity differed markedly between the study areas and years: 28% of participants for whom serologic data were available were RDT positive in the 2007 study area, compared to 8.1% and 1.4% in the 2008 and 2009 study area, respectively. Baseline antibody levels were measured in 234 participants between April and July 2007, 435 participants between February and December 2008, and 855 participants between January and December 2009. As expected, the proportion of seropositive individuals increased with age in each year. In a subset of participants followed longitudinally, RDT positivity at the prior visit was positively correlated with an increase in EIA OD values after adjusting for age in 2007 (0.261, p = 0.003) and in 2008 (0.116, p = 0.03). RDT positivity at the concurrent visit also was associated with an increase in EIA OD value in 2007 (mean increase 0.177, p = 0.002) but not in 2008 (-0.063, p =0.50). Households comprised of individuals with serologic evidence of recent malaria overlapped areas of high malaria risk for serologic data from 2009, when parasite prevalence was lowest. Conclusions: Serological surveys to whole asexual P. falciparum antigens using blood collected as dried blood spots can be used to detect temporal and spatial patterns of malaria transmission in a region of declining malaria burden, and have the potential to identify focal areas of recent transmission

Hybrid top-down/bottom-up fabrication of regular arrays of AlN nanorods for deep-UV core-shell LEDs

Core–shell nanostructures are predicted to highly improve the efficiency of deep-UV light emitting diodes (LEDs), owing to their low defect density, reduced quantum-confined Stark effect, high-quality non-polar growth and improved extraction efficiency. In this paper, we report on the nanofabrication of high-quality AlN nanorod arrays using a hybrid top-down/bottom-up approach for use as a scaffold for UV LED structures. We describe the use of Displacement Talbot Lithography to fabricate a metallic hard etch mask to allow AlN nanorod arrays to be dry etched from a planar AlN template. In particular, we investigate the impact of etching parameters on the nanorod etch rate, tapering profile and mask selectivity in order to achieve vertical-sided nanorod arrays with high aspect ratios. AlN facet recovery is subsequently explored by means of regrowth using Metal Organic Vapor Phase Epitaxy. Low pressure and high V/III ratio promote straight and smooth sidewall faceting, which results in an improvement of the optical quality compared to the initial AlN template. The promising results open new perspectives for the fabrication of high-efficiency deep-UV-emitting core–shell LEDs