A Model Ensemble Approach Enables Data-Driven Property Prediction for Chemically Deconstructable Thermosets in the Low-Data Regime.

Thermosets present sustainability challenges that could potentially be addressed through the design of deconstructable variants with tunable properties; however, the combinatorial space of possible thermoset molecular building blocks (e.g., monomers, cross-linkers, and additives) and manufacturing conditions is vast, and predictive knowledge for how combinations of these molecular components translate to bulk thermoset properties is lacking. Data science could overcome these problems, but computational methods are difficult to apply to multicomponent, amorphous, statistical copolymer materials for which little data exist. Here, leveraging a data set with 101 examples, we introduce a closed-loop experimental, machine learning (ML), and virtual screening strategy to enable predictions of the glass transition temperature (Tg) of polydicyclopentadiene (pDCPD) thermosets containing cleavable bifunctional silyl ether (BSE) comonomers and/or cross-linkers with varied compositions and loadings. Molecular features and formulation variables are used as model inputs, and uncertainty is quantified through model ensembling, which together with heavy regularization helps to avoid overfitting and ultimately achieves predictions within <15 °C for thermosets with compositionally diverse BSEs. This work offers a path to predicting the properties of thermosets based on their molecular building blocks, which may accelerate the discovery of promising plastics, rubbers, and composites with improved functionality and controlled deconstructability.

Novel concept for visible and near infrared spectro-interferometry: laser-written layered arrayed waveguide gratings.

With the growing complexity of astronomical instruments devoted to interferometry, such as MATISSE (a 4 telescope beam combiner) or FIRST (a 9 sub-apertures beam combiner), and the rebirth of space projects such as LIFE (a mid-infrared interferometer), integrated optics devices can be an interesting and complementary approach for beam combination of a large number of apertures. Moreover, one of the approaches for beam combination is pairwise combination of the inputs (either from individual telescopes or from aperture masking on a single telescope), which scales as N(N-1)/2 for an N input system. Astrophotonics devices are attractive to reduce mass and system complexity, while achieving all the beam combination in a single chip, even for a high number of inputs. The aim of this work is to develop a compact photonic device for astronomical applications and demonstrate a proof-of-concept of a spectro-interferometer. In this paper ultrafast laser inscription is used to fabricate three arrayed waveguide gratings (AWGs) stacked vertically. This arrangement enables spectral dispersion and interferometry to be measured simultaneously. Individual AWGs were designed for operation at 633 nm, and demonstrated at 633nm and 830nm. A scan between 790 and 830nm was also achieved to study the wavelength behavior of the AWG. Using a segmented mirror, light at 633nm or 830nm was injected simultaneously into three AWGs layered 40 µm apart, showing analogous behavior for all three layers and no unexpected crosstalk. Finally the three outputs were vertically combined to obtain interference fringes, showing the feasibility of spectro-interferometry and opening the way for compact astrophotonic devices devoted to phase closure studies, used in astronomy to reduce the effect of atmospheric turbulence.

Femtosecond laser written arrayed waveguide gratings with integrated photonic lanterns.

We demonstrate for the first time functional arrayed waveguide gratings (AWGs) fabricated using the femtosecond laser direct-write technique. This fabrication technique is a mask-less alternative to lithography enabling design flexibility and rapid prototyping. It is ideal for customized small scale production for new applications. The devices were demonstrated in the visible region at 632.8 nm with a measured free spectral range (FSR) of 22.2 nm, and 1.35 nm resolution. To highlight the advantages of using a 3-dimensional fabrication technique, a 3-port photonic lantern was integrated with an AWG in a single monolithic chip. Integration of this type is not feasible with lithography-based AWG fabrication and can increase the functionality of AWGs for sensing applications.

Towards femtosecond laser written arrayed waveguide gratings.

The fabrication of arrayed waveguide gratings (AWGs) using the femtosecond laser direct-write technique is investigated. We successfully demonstrate the fabrication of large planar waveguides that act as 2D free propagation zones. These slabs were found to have a highly uniform refractive index with a standard deviation of 1.97% relative to the total index contrast. The incorporation of low loss linear adiabatic tapers resulted in an increase of transmission by 90%. Strategies for manufacturing integrated laser written AWGs using continuous contouring to avoid lossy defects are discussed and demonstrated.

A 24-month evaluation of amalgam and resin-based composite restorations: Findings from The National Dental Practice-Based Research Network.

BACKGROUND: Knowing which factors influence restoration longevity can help clinicians make sound treatment decisions. The authors analyzed data from The National Dental Practice-Based Research Network to identify predictors of early failures of amalgam and resin-based composite (RBC) restorations. METHODS: In this prospective cohort study, the authors gathered information from clinicians and offices participating in the network. Clinicians completed a baseline data collection form at the time of restoration placement and annually thereafter. Data collected included patient factors, practice factors and dentist factors, and the authors analyzed them by using mixed-model logistic regression. RESULTS: A total of 226 practitioners followed up 6,218 direct restorations in 3,855 patients; 386 restorations failed (6.2 percent) during the mean (standard deviation) follow-up of 23.7 (8.8) months. The number of tooth surfaces restored at baseline helped predict subsequent restoration failure; restorations with four or more restored surfaces were more than four times more likely to fail. Restorative material was not associated significantly with longevity; neither was tooth type. Older patient age was associated highly with failure (P < .001). The failure rate for children was 4 percent, compared with 10 percent for people 65 years or older. Dentist's sex and practice workload were associated significantly with restoration longevity. CONCLUSIONS: In this prospective cohort study, these factors were significantly predictive of failure for amalgam and RBC restorations: patient's age, a higher number of surfaces restored at baseline, the dentist's sex and the practice workload. Material choice was not significantly predictive in these early results. Practical Implications. If clinicians can recognize and identify the risk factors associated with early restoration failure, more effective treatment plans may be offered to the patient.

A practical guide to occlusal management for the general practitioner.

The general dentist has a unique role as the gatekeeper of dental care. In this role, the generalist is called upon to be the primary diagnostician and is charged with the responsibility for triaging patients. Classification systems devised by many of the dental specialties are valuable tools for the diagnosis of diseases and conditions specific to the specialty, but no classifications have been directed to the general dentist. This paper describes a system being used at the University of California at San Francisco School of Dentistry that enables the general dentist to classify a patient's stomatognathic system as either physiologic or nonphysiologic and then guides the clinician toward appropriate treatment decisions.

Donor families' experience of organ donation.

This retrospective study surveyed families who consented to organ donation in the State of Queensland, Australia, from January 1991 to December 1992 inclusive, and evaluated their experience of the organ donation process. The survey questioned families in relation to the preparation they received, their understanding of brain death, the request process, influencing factors, and post donation follow-up. One hundred and eight families consented to organ donation over this 24-month period. Twelve families of paediatric donors under the age of twelve years were excluded, and twelve families were not able to be contacted. Of the remaining 84 families, 42 participated in this study. Overall the study results indicated a positive attitude towards the organ donation process. The majority of families did not find the process stressful and indicated that they were provided with sufficient information and preparation, and that the request was made in a sensitive manner. A few important issues and areas for improvement were highlighted: in particular, the need for families to have an opportunity to view the body after procurement, and the importance of counselling throughout and after the donation process.

Chronic focal sclerosing osteomyelitis associated with a cracked tooth. Report of a case.

Chronic focal sclerosing osteomyelitis is a periapical lesion that involves reactive osteogenesis evoked by chronic inflammation of the dental pulp. In most cases, this lesion develops in the mandibular molar region in response to a low-grade infection of the pulp that results from a deep carious lesion. A case is presented in which incomplete tooth fracture was the apparent cause of this type of periapical pathosis.

The role of integrin adhesion receptors in gingival wound healing.

Integrins, a family of cell adhesion receptors, play an important part in wound healing. These complex macromolecules are defined, and their roles explored.

Comparison of Roche blood culture bottle with an in-house conventional blood culture system.

A comparison was made of the in-use performance of an in-house broth blood culture in a general hospital during 8 mths in 1988 with that of a commercial biphasic culture (BCB system, Roche Products Pty Ltd, Sydney) for the corresponding period in 1989. The clinical services and the number of blood samples tested were comparable. The yields of organisms after 48 hrs incubation were similar in both systems. Staphylococcus aureus showed up 3 times as often after 24 hrs incubation in the conventional system as in the BCB system. Agitation of the BCB facilitated macroscopic detection of growth in the initial 24 hrs incubation.