Metasurface wavefront control for high-performance user-natural augmented reality waveguide glasses.

Augmented reality (AR) devices, as smart glasses, enable users to see both the real world and virtual images simultaneously, contributing to an immersive experience in interactions and visualization. Recently, to reduce the size and weight of smart glasses, waveguides incorporating holographic optical elements in the form of advanced grating structures have been utilized to provide light-weight solutions instead of bulky helmet-type headsets. However current waveguide displays often have limited display resolution, efficiency and field-of-view, with complex multi-step fabrication processes of lower yield. In addition, current AR displays often have vergence-accommodation conflict in the augmented and virtual images, resulting in focusing-visual fatigue and eye strain. Here we report metasurface optical elements designed and experimentally implemented as a platform solution to overcome these limitations. Through careful dispersion control in the excited propagation and diffraction modes, we design and implement our high-resolution full-color prototype, via the combination of analytical-numerical simulations, nanofabrication and device measurements. With the metasurface control of the light propagation, our prototype device achieves a 1080-pixel resolution, a field-of-view more than 40°, an overall input-output efficiency more than 1%, and addresses the vergence-accommodation conflict through our focal-free implementation. Furthermore, our AR waveguide is achieved in a single metasurface-waveguide layer, aiding the scalability and process yield control.

Translating the InChI: adapting neural machine translation to predict IUPAC names from a chemical identifier.

We present a sequence-to-sequence machine learning model for predicting the IUPAC name of a chemical from its standard International Chemical Identifier (InChI). The model uses two stacks of transformers in an encoder-decoder architecture, a setup similar to the neural networks used in state-of-the-art machine translation. Unlike neural machine translation, which usually tokenizes input and output into words or sub-words, our model processes the InChI and predicts the IUPAC name character by character. The model was trained on a dataset of 10 million InChI/IUPAC name pairs freely downloaded from the National Library of Medicine's online PubChem service. Training took seven days on a Tesla K80 GPU, and the model achieved a test set accuracy of 91%. The model performed particularly well on organics, with the exception of macrocycles, and was comparable to commercial IUPAC name generation software. The predictions were less accurate for inorganic and organometallic compounds. This can be explained by inherent limitations of standard InChI for representing inorganics, as well as low coverage in the training data.

Impact of early hypothalamic-pituitary-gonadal axis maturation on prostate cancer: cross-sectional analysis of a Veterans affairs cohort.

BACKGROUND: It has been hypothesized that earlier onset of puberty, and thus a more prolonged exposure to high androgen levels, increases risk of prostate cancer development. Our objective was to determine whether earlier age of first shave and height, as surrogates of pubertal onset, were associated with risk of prostate cancer diagnosis. METHODS: A prospectively collected outcomes registry of patients presenting for a prostate biopsy at the Charlie Norwood Veterans Affair Medical Center in Augusta, GA between July 1995 and June 2016 was utilized. The associations between age of first shave and height, each, and risks of a positive prostate biopsy, high grade cancer, and high volume disease were evaluated using univariable and multivariable logistic regression analysis, controlling for baseline patient demographic and oncologic characteristics. RESULTS: Our cohort included 2,456 patients. Biopsies were positive in 1,257 (51.2%) patients, of whom 293 (23.3%) and 407 (32.4%) had high grade and volume disease, respectively. Median age of first shave was 17.0 years (interquartile range 16.0-19.0) and height was 177.7 cm (172.8-182.9). On multivariable analysis, later of age of first shave was significantly associated with increased odds of a positive prostate biopsy (odds ratio for >18 versus <16 years: 5.34, P=0.02) and taller patients had significantly increased odds of high grade cancer (odds ratio for 175-180 versus <175 cm: 7.46, P=0.037). CONCLUSIONS: Amongst patients presenting for a prostate biopsy, those with a later age of first shave and taller height have an increased risk of a positive prostate biopsy and high grade prostate cancer, respectively.

Bridging the dichotomous gap between expectations and perceptions in quantifying hospice care quality.

This study uses a fuzzy logic and neural network to ascertain how service quality dimensions of the SERVQUAL model (reliability, assurance, empathy, responsiveness, and tangibility) affect overall customer satisfaction. Using a threshold logic unit to produce observation outcomes, the algorithm indicated that while reliability was the crux of the service outcome, peripheral variables (e.g., assurance, empathy, responsiveness, and tangibility) integrated emotions and feelings into the hospice service process which equated to an increased quality of life, a positive disconfirmation of expectations (service expectations were met or exceeded) and a good death experience equating to a positive perception of quality.

Experiences with a researcher-centric ELN.

Electronic Laboratory Notebooks (ELNs) are progressively replacing traditional paper books in both commercial research establishments and academic institutions. University researchers require specific features from ELNs, given the need to promote cross-institutional collaborative working, to enable the sharing of procedures and results, and to facilitate publication. The LabTrove ELN, which we use as our exemplar, was designed to be researcher-centric (i.e., not only aimed at the individual researcher's basic needs rather than to a specific institutional or subject or disciplinary agenda, but also able to be tailored because it is open source). LabTrove is being used in a heterogeneous set of academic laboratories, for a range of purposes, including analytical chemistry, X-ray studies, drug discovery and a biomaterials project. Researchers use the ELN for recording experiments, preserving data collected, and for project coordination. This perspective article describes the experiences of those researchers from several viewpoints, demonstrating how a web-based open source electronic notebook can meet the diverse needs of academic researchers.

The Bragg legacy: early days in macromolecular crystallography.

W. H. Bragg arrived in Australia in 1886 as Head of the Mathematics and Physics Departments at the University of Adelaide. His son, W. L. Bragg, grew up in Adelaide and graduated from the Physics Department. Many years later I graduated from the same department and had the opportunity to share Lawrence Bragg's recollections of life in Adelaide. As well as touching on the 'Adelaide' connection, this report briefly reviews Bragg's critical role in encouraging, supporting and establishing the field of large-molecule crystallography.