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Owning the label of misfit (or geek, gamer, nerd, etc.) may be easier as an adult than during those teenage years, but some of the shame still stirs in the undercurrent of our lives. The shame wakes up in moments where we choose to disclose our influences and interests when we are in vulnerable situations. It shows when we look inside and ask ourselves what it is we really want to do for a career. Or when our bosses ask us what we like to do on a Saturday night. Hiding can feel like wrapping up in a protective blanket but it can also feel disingenuous, and we can become so used to hiding part of ourselves that we lose the whole.

-Later on, in the 20th century, hippies would re-appropriate patchouli for its connection to India, its association with European misfits, and for a potency that would mask cannabis. It became the olfactive signature of counter-culture.

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Recent molecular dynamics simulations of the growth of [Ni0.8Fe0.2/Au] multilayers have revealed the formation of misfit-strain-reducing dislocation structures very similar to those observed experimentally. Here we report similar simulations showing the formation of edge dislocations near the interfaces of vapor-deposited (111) [NiFe/CoFe/Cu] multilayers. Unlike misfit dislocations that accommodate lattice mismatch, the dislocation structures observed here increase the mismatch strain energy. Stop-action observations of the dynamically evolving atomic structures indicate that during deposition on the (111) surface of a fcc lattice, adatoms may occupy either fcc sites or hcp sites. This results in the random formation of fcc and hcp domains, with dislocations at the domain boundaries. These dislocations enable atoms to undergo a shift from fcc to hcp sites, or vice versa. These shifts lead to missing atoms, and therefore a later deposited layer can have missing planes compared to a previously deposited layer. This dislocation formation mechanism can create tensile stress in fcc films. The probability that such dislocations are formed was found to quickly diminish under energetic deposition conditions.

Background and aim: Compromised fit between the contact surfaces of screw-retained implant-supported fixed dentures (IFDs) is thought to create uncontrolled strains in the prosthetic components and peri-implant tissues, thus evoking biological and technical complications such as bone loss, screw loosening, component fractures and, at worst, loss of implants or prostheses. The aim of this systematic review was to evaluate the impact of marginal misfit on the clinical outcomes of IFDs, and to elucidate definition and assessment methods for passive fit.

Materials and methods: A systematic review of the literature was conducted with a PICO question: "For partially or complete edentulous subjects with screw-retained IFDs, does the marginal misfit at the implant-prosthesis interfaces have an impact on the clinical outcomes?". A literature search was performed electronically in PubMed (MEDLINE) with the help of Boolean operators to combine key words, and by hand search in relevant journals. English written in vivo studies published before August 31, 2016 that reported on both clinical outcome and related implant prosthesis misfit (gap, strains, torque) were selected using predetermined inclusion criteria.

Results: The initial search yielded 2626 records. After screening and a subsequent filtering process, five human and five animal studies were included in the descriptive analysis. The selected studies used different methods to assess misfit (linear distortion, vertical gap, strains, screw torque). While two human studies evaluated the biological response and technical complications prospectively over 6 and 12 months, the animal studies had an observation period < 12 weeks. Four human studies analysed retrospectively the 3 to 32 years' outcomes. Screw-related complications were observed, but biological sequelae could not be confirmed. Although the animal studies had different designs, bone adaptation and implant displacement was found in histological analyses. Due to the small number of studies and the heterogenic designs and misfit assessment methods, no meta-analysis of the data could be performed.

Conclusions: The current literature provides insufficient evidence as to the effect of misfit at the prosthesis-implant interface on clinical outcomes of screw-retained implant-supported fixed dentures. Marginal gaps and static strains due to screw tightening were not found to have negative effects on initial osseointegration or peri-implant bone stability over time. Based on two clinical studies, the risk for technical screw-related complications was slightly higher. While the degree of tolerable misfit remains a matter of debate, the present data do not imply that clinicians neglect good fit, but aim to achieve the least misfit possible. Conflict of interest statement: The authors declare no conflict of interest. The review was conducted as part of the 2016 Foundation of Oral Rehabilitation Consensus Conference on "Prosthetic Protocols in Implant-based Oral Rehabilitation".

The inclusion of benchmark misfit on performance changes everything! Instead of issue selection driving a slight increase in risk with a tremendous increase in return, misfit lowered volatility with selection adding substantially to risk but only modestly to return. This changes the narrative completely.

The face-centered cubic medium-entropy alloy NiCoCr has received considerable attention for its good mechanical properties, uncertain stacking fault energy, etc, some of which have been attributed to chemical short-range order (SRO). Here, we examine the yield strength and misfit volumes of NiCoCr to determine whether SRO has measurably influenced mechanical properties. Polycrystalline strengths show no systematic trend with different processing conditions. Measured misfit volumes in NiCoCr are consistent with those in random binaries. Yield strength prediction of a random NiCoCr alloy matches well with experiments. Finally, we show that standard spin-polarized density functional theory (DFT) calculations of misfit volumes are not accurate for NiCoCr. This implies that DFT may be inaccurate for other subtle structural quantities such as atom-atom bond distance so that caution is required in drawing conclusions about NiCoCr based on DFT. These findings all lead to the conclusion that, under typical processing conditions, SRO in NiCoCr is either negligible or has no systematic measurable effect on strength.

Here, literature experiments on tensile strength are first examined, and show no indication of strength variations with processing conditions. Long-time lower-temperature annealing experiments are then shown to have no effect on the hardness of NiCoCr as compared with the initial sample annealed at high temperature. Precise measurements of the lattice constants of NiCoCr and surrounding compositions allow for an accurate determination of the Ni, Co, and Cr misfit/apparent volumes, which generally agree with those found for random Ni2Co and Ni2Cr binary alloys. The measured misfit volumes and single-crystal elastic constants then enable application of a theory to predict the initial yield strength of a random alloy and good agreement with experimental values is obtained. With the misfit volumes in NiCoCr carefully measured here for the first time, we then show that first-principles DFT calculations are not accurate for the misfit volumes in NiCoCr, which has implications for the previous analysis of SRO from EXAFS experiments10 and for the development of interatomic potentials based solely on DFT inputs11. Based on all of these findings, we can conclude that, in the NiCoCr alloys fabricated and tested to date, SRO is either negligible or exists but does not have any important effect on yield strength and misfit volumes.

With the experimental misfit volumes and two recent literature values for the room temperature single-crystal elastic constants30,31, we can predict the initial yield strength of NiCoCr within the framework of an existing solute strengthening theory for random alloys32,33, which has previously shown quantitative success for a number of HEAs25,32,33,34,35,36. We can then compare the random alloy strength prediction against experiments.

It has been very common to apply standard spin-polarized DFT to compute properties and understand atomic structures and local atomic distortions in HEAs8,9,17,39,40,41. It is well-established that DFT predicts lattice constants and elastic constants can differ moderately from experiments. Table 1 shows that DFT predictions of elastic constants in random NiCoCr and Ni2Cr are in reasonable agreement with experiments, suggesting DFT may be generally applicable to NiCoCr. DFT may also provide reasonable results for the energetic driving forces that could cause SRO in NiCoCr9,41. However, with accurately measured solute misfit volumes, we can demonstrate that, unfortunately, DFT provides very poor results for the misfit volumes in NiCoCr. This makes DFT possibly unsuitable for quantitative use in drawing conclusions about local atomic environments.

The error bar in DFT data indicates the 95% confidence interval in the linear regression in the misfit volume calculation. Black bars are the alloy atomic volumes. All the results are from fcc structure unless indicated and shown as hollow symbols. ff782bc1db