Multi-dimensional modeling and simulation of semiconductor nanophotonic devices

Self-consistent modeling and multi-dimensional simulation of semiconductor nanophotonic devices is an important tool in the development of future integrated light sources and quantum devices. Simulations can guide important technological decisions by revealing performance bottlenecks in new device concepts, contribute to their understanding and help to theoretically explore their optimization potential. The efficient implementation of multi-dimensional numerical simulations for computer-aided design tasks requires sophisticated numerical methods and modeling techniques. We review recent advances in device-scale modeling of quantum dot based single-photon sources and laser diodes by self-consistently coupling the optical Maxwell equations with semiclassical carrier transport models using semi-classical and fully quantum mechanical descriptions of the optically active region, respectively. For the simulation of realistic devices with complex, multi-dimensional geometries, we have developed a novel hp-adaptive finite element approach for the optical Maxwell equations, using mixed meshes adapted to the multi-scale properties of the photonic structures. For electrically driven devices, we introduced novel discretization and parameter-embedding techniques to solve the drift-diffusion system for strongly degenerate semiconductors at cryogenic temperature. Our methodical advances are demonstrated on various applications, including vertical-cavity surface-emitting lasers, grating couplers and single-photon sources

Preparing for pandemic influenza: The need for enhanced surveillance

In the US, planning for the next influenza pandemic is occurring in parallel at the national, state and local levels. Certain issues, such as conducting surveillance and purchasing pandemic vaccine, require co-ordination at the national level. However, most prevention and control actions will be implemented at the state and local levels, which vary widely in terms of population demographics, culture (e.g. rural versus urban) and available resources. In 1995, a survey by the Council of State and Territorial Epidemiologists (CSTE) found that only 29 (59%) states perceived a need to develop a specific influenza pandemic plan for their jurisdiction. Since then, the process of developing state and local plans has gained considerable momentum. Integration of these efforts with the national planning process has been facilitated by: (1) the mutual involvement of state and federal staff in both processes; (2) the sharing of draft documents; (3) the ongoing occurrence of local and national co-ordinating meetings; (4) the provision of financial resources by the federal government. So far, approximately 12 states either have drafted or begun drafting a state and local influenza pandemic plan. One of the benefits of the collaborative planning process has been the development of new working relationships and partnerships among several agencies at the state, local and national levels. Such efforts will improve our collective ability to rapidly investigate and control other emerging or re-emerging public health threats in the 21st century, be it a bioterrorist event, pandemic influenza, or any other catastrophic health event. © 2002 Published by Elsevier Science Ltd.Link_to_subscribed_fulltex

Integrating Electronic Medical Records and Claims Data for Influenza Vaccine Research

Real-world evidence (RWE) increasingly informs public health and healthcare decisions worldwide. A large database has been created (“Integrated Dataset”) that integrates primary care electronic medical records with pharmacy and medical claims data on >123 million US patients since 2014. This article describes the components of the Integrated Dataset and evaluates its representativeness to the US population and its potential use in evaluating influenza vaccine effectiveness. Representativeness to the US population (2014–2019) was evaluated by comparison with demographic information from the 2019 US census and the National Ambulatory Medical Care Survey (NAMCS). Variables included in the Integrated Dataset were evaluated against World Health Organization (WHO) defined key and non-critical variables for evaluating influenza vaccine performance. The Integrated Dataset contains a variety of information, including demographic data, patient medical history, diagnoses, immunizations, and prescriptions. Distributions of most age categories and sex were comparable with the US Census and NAMCS populations. The Integrated Dataset was less diverse by race and ethnicity. Additionally, WHO key and non-critical variables for the estimation of influenza vaccine effectiveness are available in the Integrated Dataset. In summary, the Integrated Dataset is generally representative of the US population and contains key variables for the assessment of influenza vaccine effectiveness

Acute Hemorrhagic Conjunctivitis: Investigation of a Large-scale Community Outbreak in Dade County, Florida

An outbreak of acute hemorrhagic conjunctivitis (AHC) due to enterovirus type 70 occurred in Dade County, Florida, from September to December 1981. Younger age groups, members of larger households, and the poor were at significantly greater risk of acquiring AHC than others in the community. Schoolchildren were most likely to introduce AHC into the household. After exclusion of all affected children from school, there was a dramatic reduction in reported cases, with attack rates declining more rapidly for school-aged children than for other age groups. Although AHC spread readily among family members, a retrospective study of 124 affected households showed an association between lower attack rates and simple hygienic measures. Should outbreaks of AHC recur, measures to reduce transmission should include exclusion of affected schoolchildren and educating the public about hygienic precautions.(JAMA 1983;249:1283-1289

Pivotal <i>Shigella</i> Vaccine Efficacy Trials—Study Design Considerations from a <i>Shigella</i> Vaccine Trial Design Working Group

Vaccine candidates for Shigella are approaching phase 3 clinical trials in the target population of young children living in low- and middle-income countries. Key study design decisions will need to be made to maximize the success of such trials and minimize the time to licensure and implementation. We convened an ad hoc working group to identify the key aspects of trial design that would meet the regulatory requirements to achieve the desired indication of prevention of moderate or severe shigellosis due to strains included in the vaccine. The proposed primary endpoint of pivotal Shigella vaccine trials is the efficacy of the vaccine against the first episode of acute moderate or severe diarrhea caused by the Shigella strains contained within the vaccine. Moderate or severe shigellosis could be defined by a modified Vesikari score with dysentery and molecular detection of vaccine-preventable Shigella strains. This report summarizes the rationale and current data behind these considerations, which will evolve as new data become available and after further review and consultation by global regulators and policymakers

Protein camouflage in cytochrome c–calixarene complexes

Small molecules that recognize protein surfaces are important tools for modifying protein interaction properties. Since the 1980s, several thousand studies concerning calixarenes and host–guest interactions have been published. Although there is growing interest in protein–calixarene interactions, only limited structural information has been available to date. We now report the crystal structure of a protein–calixarene complex. The water-soluble p-sulfonatocalix[4]arene is shown to bind the lysine-rich cytochrome c at three different sites. Binding curves obtained from NMR titrations reveal an interaction process that involves two or more binding sites. Together, the data indicate a dynamic complex in which the calixarene explores the surface of cytochrome c. In addition to providing valuable information on protein recognition, the data also indicate that the calixarene is a mediator of protein–protein interactions, with potential applications in generating assemblies and promoting crystallization