Clinical Outcomes of Implant Placement Through Impacted Tooth: A Systematic Review and Meta-Analysis

Introduction: Conventional implant protocols require extraction of impacted teeth, risking bone loss and morbidity. This review evaluates implant placement through impacted teeth as a tissue-preserving alternative. Objectives: To assess clinical success and complications of implants placed through impacted teeth—a minimally invasive alternative technique aimed at preserving alveolar bone. Methods: Following PRISMA guidelines and JBI tools, databases (PubMed, Scopus, Web of Science) were searched for human studies with ≥12 months’ follow-up. Meta-analysis employed fixed/random-effects models; heterogeneity was evaluated via I². Results: From 262 records, seven studies (case reports/series) were included. Mean implant survival was 95.8% (range: 92.3–98.4%). Primary stability reached 98%. Complication rates were low (peri-implantitis 3.1%, implant failure 4.2%, marginal bone loss 2.8%). No significant differences in peri-implant bone loss versus conventional implants.Conclusions: : Implant placement through impacted teeth demonstrates high short-term survival and low complication rates. While promising as a minimally invasive technique, larger randomized controlled trials with longer follow-up are essential for validation

Bennu and Ryugu: diamonds in the sky

Rapidly spinning and loosely aggregated asteroids appear to take on diamond-shaped profiles, with elevated poles as well as equators. The evolutionary processes that form these characteristic shapes remain a matter of debate. In this paper, we propose a novel model, based on debris accretion, to explain these diamond-shaped profiles. We derive an analytic expression for the shapes of such rapidly spinning rubble piles based on the principle that as rubble is deposited it assumes a critical angle of repose. We show that this expression correctly reproduces diamond shaped profiles. We also conduct granular simulations of debris deposition and show that simulated shapes are in striking accord with both observations and analytical results. Our results suggest that non-uniform debris accumulation, which is overlooked in current models, may play a cardinal role in the formation of diamond-shaped asteroids

Identifying inhibitors of epithelial–mesenchymal plasticity using a network topology-based approach

Metastasis is the cause of over 90% of cancer-related deaths. Cancer cells undergoing metastasis can switch dynamically between different phenotypes, enabling them to adapt to harsh challenges, such as overcoming anoikis and evading immune response. This ability, known as phenotypic plasticity, is crucial for the survival of cancer cells during metastasis, as well as acquiring therapy resistance. Various biochemical networks have been identified to contribute to phenotypic plasticity, but how plasticity emerges from the dynamics of these networks remains elusive. Here, we investigated the dynamics of various regulatory networks implicated in Epithelial-mesenchymal plasticity (EMP)-an important arm of phenotypic plasticity-through two different mathematical modelling frameworks: a discrete, parameter-independent framework (Boolean) and a continuous, parameter-agnostic modelling framework (RACIPE). Results from either framework in terms of phenotypic distributions obtained from a given EMP network are qualitatively similar and suggest that these networks are multi-stable and can give rise to phenotypic plasticity. Neither method requires specific kinetic parameters, thus our results emphasize that EMP can emerge through these networks over a wide range of parameter sets, elucidating the importance of network topology in enabling phenotypic plasticity. Furthermore, we show that the ability to exhibit phenotypic plasticity correlates positively with the number of positive feedback loops in a given network. These results pave a way toward an unorthodox network topology-based approach to identify crucial links in a given EMP network that can reduce phenotypic plasticity and possibly inhibit metastasis-by reducing the number of positive feedback loops

Ray Systems in Granular Cratering

In classical experiments of granular cratering, a ball dropped on an evened-out bed of grains ends up within a crater surrounded by a uniform blanket of ejecta. In this Letter, we show that the uniform blanket of ejecta changes to a ray system, or set of radial streaks of ejecta, where the surface of the granular bed includes undulations, a factor that has not been addressed to date. By carrying out numerous experiments and computational simulations thereof, we ascertain that the number of rays in a ray system proportional, variantD/lambda, where D is the diameter of the ball and lambda is the wavelength of the undulations. Further, we show that the ejecta in a ray system originates in a narrow annulus of diameter D with the center at the site of impact. Our findings may help shed light on the enigmatic ray systems that ring many impact craters on the Moon and other planetary bodies

Size Sorting on the Rubble-Pile Asteroid Itokawa

Photographs of the asteroid Itokawa reveal unexpectedly strong size segregation between lowlands populated almost entirely by small pebbles and highlands consisting of larger boulders. We propose that this segregation may be caused by a simple and unexplored effect: pebbles accreting onto the asteroid rebound from boulders, but sink into pebbly regions. By number, overwhelmingly more particles on Itokawa are pebbles, and collisions involving these pebbles must unavoidably cause pebbly regions to grow. We carry out experiments and simulations that demonstrate that this mechanism of size sorting based on simple counting of grains produces strong lateral segregation that reliably obeys an analytic formula

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

A skeleton-and-bubble model of elastic open-cell foams for finite element analysis at large deformations

We formulate a new unit-cell model of elastic open-cell foams. In this model, the conventional skeleton of open-cell foams is supplemented by fitting a thin-walled bubble within each cavity of the skeleton, as a substitute for the membranes that occlude the openings of the skeleton in elastic polyether polyurethane foams. The model has 9 parameters, and the value of each parameter may be readily estimated for any given foam. We implement the model as a user-defined material subroutine in the finite-element code ABAQUS. To calibrate the model, we carry out fully nonlinear, three-dimensional finite-element computational simulations of the experiments of Dai et al., in which a set of five polyether-polyurethane EOC foams covering the entire range of commercially available relative densities was tested under five loading conditions: compression along the rise direction, compression along a transverse direction, tension along the rise direction, simple shear combined with compression along the rise direction, and hydrostatic pressure combined with compression along the rise direction. We show that, with a suitable choice of the values of the parameters of the model, the model is capable of reproducing the most salient trends evinced in the experimental stress-strain curves. We also show that the model can no longer reproduce all of these trends if the bubbles be excluded from the model, and conclude that the bubbles play a crucial role at large deformations, at least under certain loading conditions. Next, we turn our attention to the stretch fields. Of special interest to us are the two-phase stretch fields associated with a phase transition. These fields consist of mixtures of two configurational phases of the foam, a high-deformation phase and a low-deformation phase. We show that the stretch fields that obtain in our computational simulations are in good accord with the digital-image-correlation measurements of Dai et al., except for simple shear combined with compression along the rise direction. For this loading condition, Dai et al. concluded that the stretch fields remained continuous and there was no evidence of distinct configurational phases in the foam. And yet, Dai et al. might have concluded otherwise had they probed the stretch fields close to the lateral faces of the specimen, where according to our computational simulations they would have found circumscribed nuclei of the high-deformation phase. To settle the matter, we subject a foam specimen to simple shear combined with compression along the rise direction, measure the stretch fields via a digital-image-correlation technique, and find discontinuities in the stretch fields--but only close to the lateral faces of the specimen, just as expected on the basis of our computational simulations. All of the major features of the stretch fields turn out to be well reproduced in the computational simulations. In the last part of this thesis, we assess the capacity of the new model to yield reliable predictions of the mechanical response of foams under punching, a common type of loading in applications of elastic polyether polyurethane foams. In punching problems the geometry is complex, the stress fields are highly spatially heterogeneous, the deformations are very large, and the use of finite-element simulations is indispensable. We have recourse to data from numerous punching experiments in which tall and short specimens of foams of three low values of relative density were penetrated by a wedge-shaped punch and a conical punch. For each experiment we run a fully nonlinear, three-dimensional finite-element computational simulation and find the simulated force--penetration curve to be in good accord with the corresponding experimental force--penetration curve. Wedge-shaped punches and conical punches lack an intrinsic characteristic length, a fact that has been exploited to carry out a simple but powerful theoretical analysis of the mechanical response of foams under punching. Some of the assumptions and simplifications of this theoretical analysis have remained inaccessible to direct experimental verification, and we use our computational simulations to show that these assumptions and simplifications are justified. Our results on punching serve to underscore the importance of phase transitions in the mechanics of EOC foams. The force-penetration curves display a number of striking features, and we can relate each one of these features to the presence of two configurational phases in the foam. Feature by feature the relation is so specific and intricate that we are lead to conclude that the force-penetration curves could be taken by themselves as proof of the occurrence of phase transitions, even in the absence of any direct experimental evidence of the stretch fields. A number of models of EOC foams might not allow for the occurrence of phase transitions and still be able to account for numerous stress-stretch curves measured under compression along the rise direction, for example. But the force-penetration curves are inextricably linked to the prevalence of two-phase stretch fields, and it is likely that no model can account for these curves unless it allows for the occurrence of phase transitions