Exciton Dynamics in Rubrene Single Crystals

In this work, transient grating pump and probe experiments are used to investigate excitonic processes in the rubrene single crystal. Rubrene is a high quality organic crystal with particularly intriguing material properties that make it interesting for the study of various physical processes of importance for optoelectronics.On the nanosecond time scale we find that bimolecular interactions cause a photoinduced excited state density on the order of approximately 0.5 x 10^20 cm^-3 - corresponding to an average distance of approximately 3 nm between individual states - to decrease by a factor of two after 2 ns, following a typical power-law decay. We assign the observed power-law decays to high-density interactions between excited states. Because of the high efficiency singlet exciton fission observed in rubrene, these bimolecular interactions are likely those between triplet excitons or a singlet exciton and a pair of triplet excitons in a coherent quantum superposition.Transient grating experiments performed on the picosecond time scale are then used to track the build-up of the photoinduced excited state. The build up to a quasi steady-state amplitude of the grating within 10 ps is consistent with the affirmation that the build-up tracks the creation of triplet states by singlet fission, which then implies the bimolecular interactions seen on the nanosecond time scale are indeed those of triplets or the coherent quantum superposition of a singlet and a pair or triplet excitons.Lastly we use the transient grating techniques in a spectroscopic capacity in order to track how the observed grating dynamics and the exciton dynamics that can be inferred from it depend on the energy of the photons used for excitation, which determine the initial excitation energy deposited in the material and the vibrational mode of the excited state. We find that the time it takes to create triplet excitons by fission increases with increasing excitation energy, and once an excitation threshold of approximately 2.7 eV is passed, corresponding to approximately the third vibronic resonance of the singlet state, we loose the ability to track the triplet population in our experiment

VirtualIdentity : privacy preserving user profiling

User profiling from user generated content (UGC) is a common practice that supports the business models of many social media companies. Existing systems require that the UGC is fully exposed to the module that constructs the user profiles. In this paper we show that it is possible to build user profiles without ever accessing the user's original data, and without exposing the trained machine learning models for user profiling - which are the intellectual property of the company - to the users of the social media site. We present VirtualIdentity, an application that uses secure multi-party cryptographic protocols to detect the age, gender and personality traits of users by classifying their user-generated text and personal pictures with trained support vector machine models in a privacy preserving manner

I\u27ve Found I Can\u27t Live With Out You

https://digitalcommons.library.umaine.edu/mmb-vp/1580/thumbnail.jp

Periodic turning and oscillation therapy and their effect on airway clearance

A two-part study was performed to determine the effect of periodic turning and oscillation therapy on the mechanically ventilated patient's airway clearance. A secondary analysis of data was performed to compare the effect on airway clearance between subjects on an air-flotation, continuous oscillating bed, the BiodyneTM (n = 8), and subjects on a standard hospital bed manually turned every two hours (n = 10). Airway clearance was evaluated over a three-day period: (1) frequency of suctioning, (2) description of secretions, (3) a/APO₂ ratio, and (4) respiratory compliance measures. The secondary analysis findings indicated no statistically significant differences between the BiodyneTM group and the standard group. A third group of subjects, the RotorestTM bed subjects (n = 7), was retrospectively assessed for effective airway clearance and reported as a descriptive study. The RotorestTM group's sputum appearance, which changed from "purulent-bloody" to "clear-light yellow," demonstrated significant clearing over three days (χ² = 4.24, df = 1)

VirtualIdentity: Privacy Preserving User Profiling

User profiling from user generated content (UGC) is a common practice that supports the business models of many social media companies. Existing systems require that the UGC is fully exposed to the module that constructs the user profiles. In this paper we show that it is possible to build user profiles without ever accessing the user’s original data, and without exposing the trained machine learning models for user profiling – which are the intellectual property of the company – to the users of the social media site. We present VirtualIdentity, an application that uses secure multi-party cryptographic protocols to detect the age, gender and personality traits of users by classifying their user generated text and personal pictures with trained support vector machine models in a privacy preserving manner.status: publishe

Lessons learned: Retrospective assessment of outcomes and management of patients with advanced HIV disease in a semi-urban polyclinic in Epworth, Zimbabwe.

IntroductionHIV continues to be one of the leading causes of infectious death worldwide and presentation with advanced HIV disease is associated with increased morbidity and mortality. Recommendations for the management of advanced HIV disease include prompt screening and treatment of opportunistic infections, rapid initiation of ART and intensified adherence support. We present treatment outcomes of a cohort of patients presenting with advanced HIV disease in a semi-urban Zimbabwean polyclinic.MethodsRetrospective cohort analysis of adult patients enrolled for care at Epworth polyclinic, Zimbabwe between 2007 and end June 2016. Treatment outcomes at 6 and 12 months were recorded. Multivariate logistical regression analysis was undertaken to identify risk factors for presentation with advanced HIV Disease (CD4 count less than 200 cells/mm3 or WHO stage 3 or 4) and risks for attrition at 12 months.Results16,007 anti-retroviral therapy naive adult patients were included in the final analysis, 47.4% of whom presented with advanced HIV disease. Patients presenting with advanced HIV disease had a higher mortality rate at 12 months following enrollment compared to early stage patients (5.11% vs 0.45%). Introduction of a package of differentiated care for patients with a CD4 count of less than 100 cells/mm3 resulted in diagnosis of cryptococcal antigenaemia in 7% of patients and a significant increase in the diagnosis of TB, although there was no significant difference in attrition at 6 or 12 months for these patients compared to those enrolled prior to the introduction of the differentiated care.ConclusionsThe burden of advanced HIV disease remained high over the study period in this semi-urban polyclinic in Zimbabwe. Introduction of a package of differentiated care for those with advanced HIV disease increased the diagnosis of opportunistic infections and represents a model of care which can be replicated in other polyclinics in the resource constrained Zimbabwean context

Impact and cost-effectiveness of Haemophilus influenzae type b conjugate vaccination in India.

OBJECTIVE: To estimate the potential health impact and cost-effectiveness of nationwide Haemophilus influenzae type b (Hib) vaccination in India. STUDY DESIGN: A decision support model was used, bringing together estimates of demography, epidemiology, Hib vaccine effectiveness, Hib vaccine costs, and health care costs. Scenarios favorable and unfavorable to the vaccine were evaluated. State-level analyses indicate where the vaccine might have the greatest impact and value. RESULTS: Between 2012 and 2031, Hib conjugate vaccination is estimated to prevent over 200 000 child deaths (∼1% of deaths in children <5 years of age) in India at an incremental cost of US$127 million per year. From a government perspective, state-level cost-effectiveness ranged from US$192 to US$1033 per discounted disability adjusted life years averted. With the inclusion of household health care costs, cost-effectiveness ranged from US$155-US$939 per discounted disability adjusted life year averted. These values are below the World Health Organization thresholds for cost effectiveness of public health interventions. CONCLUSIONS: Hib conjugate vaccination is a cost-effective intervention in all States of India. This conclusion does not alter with plausible changes in key parameters. Although investment in Hib conjugate vaccination would significantly increase the cost of the Universal Immunization Program, about 15% of the incremental cost would be offset by health care cost savings. Efforts should be made to expedite the nationwide introduction of Hib conjugate vaccination in India