Long-term stability of early implant placement with contour augmentation

In this prospective case series study, 20 patients with an implant-borne single crown following early implant placement with simultaneous contour augmentation were followed for 6 years. Clinical, radiologic, and esthetic parameters were assessed. In addition, cone beam computed tomography (CBCT) was used at 6 years to examine the facial bone wall. During the study period, all 20 implants were successfully integrated, and the clinical parameters remained stable over time. Pleasing esthetic outcomes were noted, as assessed by the pink esthetic scores. None of the implants developed mucosal recession of 1 mm or more. The periapical radiographs yielded stable peri-implant bone levels, with a mean DIB of 0.44 mm at 6 years. The CBCT scans showed that all 20 implants had a detectable facial bone wall at 6 years, with a mean thickness of around 1.9 mm. In summary, this prospective case series study demonstrated stable peri-implant hard and soft tissues for all 20 implants, and pleasing esthetic outcomes overall. The follow-up of 6 years confirmed that the risk for mucosal recession is low with early implant placement. In addition, contour augmentation with guided bone regeneration (GBR) was able to establish and maintain a facial bone wall in all 20 patients.

Long-term stability of contour augmentation with early implant placement following single tooth extraction in the esthetic zone: a prospective, cross-sectional study in 41 patients with a 5- to 9-year follow-up

BACKGROUND Early implant placement with simultaneous contour augmentation is documented with short- and medium-term studies. The long-term stability of contour augmentation is uncertain. METHODS In this prospective, cross-sectional study, 41 patients with an implant-borne single crown were examined twice, in 2006 and 2010. Clinical, radiologic, and esthetic parameters were assessed at both examinations. In addition, a cone beam computed tomographic (CBCT) image was obtained during the second examination to assess the dimensions of the facial bone wall. RESULTS All 41 implants demonstrated ankylotic stability without signs of peri-implant infection at both examinations. The clinical parameters remained stable over time. Satisfactory esthetic outcomes were noted, as assessed by the pink and white esthetic score (PES/WES) indices. Overall, the PES scores were slightly higher than the WES scores. None of the implants developed mucosal recession over time, as confirmed by values of the distance between implant shoulder and mucosal margin and cast measurements. The periapical radiographs yielded stable peri-implant bone levels, with a mean distance between implant shoulder and first visible bone-implant contact value of 2.18 mm. The CBCT analysis demonstrated a mean thickness of the facial bone wall ≈2.2 mm. In two implants (4.9%) no facial bone wall was detectable radiographically. CONCLUSIONS This prospective cross-sectional study demonstrates stable peri-implant hard and soft tissues for all 41 implants examined and satisfactory esthetic outcomes overall. The follow-up of 5 to 9 years confirmed again that the risk for mucosal recession is low with early implant placement. In addition, contour augmentation with guided bone regeneration was able to establish and maintain a facial bone wall in 95% of patients.

Reliability and stability of lucid dream and nightmare frequency scales

Lucid dream and nightmare frequencies vary greatly between individuals and to assess these differences reliable instruments are needed. The present study aimed to examine the reliability of eight-point scales for measuring lucid dream and nightmare frequencies. The scales were administered twice (with a four-week interval) to 93 sport students. A re-test reliability for the lucid dream frequency was found r=.89 (p<.001) and for the nightmare frequency r=.75 (p<.001). Both eight-point scales appear to be reliable measures for assessing individual differences in lucid dream and nightmare frequencies.

Epigenetic diversity increases the productivity and stability of plant populations

Biological diversity within species can be an important driver of population and ecosystem functioning. Until now, such within-species diversity effects have been attributed to underlying variation in DNA sequence. However, within-species differences, and thus potentially functional biodiversity, can also be created by epigenetic variation. Here, we show that epigenetic diversity increases the productivity and stability of plant populations. Epigenetically diverse populations of Arabidopsis thaliana produce up to 40% more biomass than epigenetically uniform populations. The positive epigenetic diversity effects are strongest when populations are grown together with competitors and infected with pathogens, and they seem to be partly driven by complementarity among epigenotypes. Our study has two implications: first, we may need to re-evaluate previous within-species diversity studies where some effects could reflect epigenetic diversity; second, we need to incorporate epigenetics into basic ecological research, by quantifying natural epigenetic diversity and testing for its ecological consequences across many different species.

Triality, periodicity and stability of SO(8) gauged supergravity

While electromagnetic duality is a symmetry of many supergravity theories, this is not the case for the N = 8 gauged theory. It was recently shown that this rotation leads to a one-parameter family of SO(8) supergravities. It is an open question what the period of this parameter is. This issue is investigated in the SO(4) invariant sectors of the theory. We classify such critical points and find a novel branch of non-supersymmetric and unstable solutions, whose embedding is related via triality to the two known ones. Secondly, we show that the three branches of solutions lead to a π/4 periodicity of the vacuum structure. The general interrelations between triality and periodicity are discussed. Finally, we comment on the connection to other gauge groups as well as the possibility to achieve (non-)perturbative stability around AdS/Mkw/dS transitions.

The long-term stability of self-esteem: Its time-dependent decay and nonzero asymptote

How stable are individual differences in self-esteem? We examined the time-dependent decay of rank-order stability of self-esteem and tested whether stability asymptotically approaches zero or a nonzero value across long test–retest intervals. Analyses were based on 6 assessments across a 29-year period of a sample of 3,180 individuals aged 14 to 102 years. The results indicated that, as test–retest intervals increased, stability exponentially decayed and asymptotically approached a nonzero value (estimated as .43). The exponential decay function explained a large proportion of variance in observed stability coefficients, provided a better fit than alternative functions, and held across gender and for all age groups from adolescence to old age. Moreover, structural equation modeling of the individual-level data suggested that a perfectly stable trait component underlies stability of self-esteem. The findings suggest that the stability of self-esteem is relatively large, even across very long periods, and that self-esteem is a trait-like characteristic.

High-Pressure Behavior and Phase Stability of Al5BO9, a Mullite-Type Ceramic Material

Phase stability, elastic behavior, and pressure-induced structural evolution of synthetic boron-mullite Al5BO9 (a = 5.6780(7), b = 15.035(6), and c =7.698(3) Å, space group Cmc21, Z = 4) were investigated up to 25.6(1) GPa by in situ single-crystal synchrotron X-ray diffraction with a diamond anvil cell (DAC) under hydrostatic conditions. No evidence of phase transition was observed up to 21.7(1) GPa. At 25.6(1) GPa, the refined unit-cell parameters deviated significantly from the compressional trend, and the diffraction peaks appeared broader than at lower pressure. At 26.7(1) GPa, the diffraction pattern was not indexable, suggesting amorphization of the material or a phase transition to a high-pressure polymorph. Fitting the P–V data up to 21.7(1) GPa with a second-order Birch–Murnaghan Equation-of-State, we obtained a bulk modulus KT0 = 164(1) GPa. The axial compressibilities, here described as linearized bulk moduli, are as follows: KT0(a) = 244(9), KT0(b) = 120(4), and KT0(c) = 166(11) GPa (KT0(a):KT0(b):KT0(c) = 2.03:1:1.38). The structure refinements allowed a description of the main deformation mechanisms in response to the applied pressure. The stiffer crystallographic direction appears to be controlled by the infinite chains of edge-sharing octahedra running along [100], making the structure less compressible along the a-axis than along the b- and c-axis.

Denaturation and unfolding of human anaphylatoxin C3a: an unusually low covalent stability of its native disulfide bonds.

The complement C3a anaphylatoxin is a major molecular mediator of innate immunity. It is a potent activator of mast cells, basophils and eosinophils and causes smooth muscle contraction. Structurally, C3a is a relatively small protein (77 amino acids) comprising a N-terminal domain connected by 3 native disulfide bonds and a helical C-terminal segment. The structural stability of C3a has been investigated here using three different methods: Disulfide scrambling; Differential CD spectroscopy; and Reductive unfolding. Two uncommon features regarding the stability of C3a and the structure of denatured C3a have been observed in this study. (a) There is an unusual disconnection between the conformational stability of C3a and the covalent stability of its three native disulfide bonds that is not seen with other disulfide proteins. As measured by both methods of disulfide scrambling and differential CD spectroscopy, the native C3a exhibits a global conformational stability that is comparable to numerous proteins with similar size and disulfide content, all with mid-point denaturation of [GdmCl](1/2) at 3.4-5M. These proteins include hirudin, tick anticoagulant protein and leech carboxypeptidase inhibitor. However, the native disulfide bonds of C3a is 150-1000 fold less stable than those proteins as evaluated by the method of reductive unfolding. The 3 native disulfide bonds of C3a can be collectively and quantitatively reduced with as low as 1mM of dithiothreitol within 5 min. The fragility of the native disulfide bonds of C3a has not yet been observed with other native disulfide proteins. (b) Using the method of disulfide scrambling, denatured C3a was shown to consist of diverse isomers adopting varied extent of unfolding. Among them, the most extensively unfolded isomer of denatured C3a is found to assume beads-form disulfide pattern, comprising Cys(36)-Cys(49) and two disulfide bonds formed by two pair of consecutive cysteines, Cys(22)-Cys(23) and Cys(56)-Cys(57), a unique disulfide structure of polypeptide that has not been documented previously.

Mechanical and Chemical Stability of Injection-Molded Microcantilevers Used for Sensing

Ultraviolet-ozone treatment is used as a standard surface cleaning procedure for removal of molecular organic contamination from analytical and sensing devices. Here, it is applied for injection-molded polymer microcantilevers before characterization and sensing experiments. This article examines the effects of the surface cleaning process using commercial equipment, in particular on the performance and mechanical properties of the cantilevers. It can be shown that the first chemical aging process essentially consist of the cross linking of the polymer chains together with a physical aging of the material. For longer exposure, the expected thermo-oxidative formation of carbonyl groups sets in and an exposure dependent chemical degradation can be detected. A process time of 20 min was found suitable as a trade-off between cleaning and stability

Stability of specific immunoglobulin secretion by EBV-transformed lymphoblastoid cells and human-murine heterohybridomas

The purpose of this project was to determine if stability of specific antibody secretion improved after fusion of Epstein-Barr virus (EBV)-transformed lymphoblastoid cells with P3X63Ag8.653 murine myeloma cells. Production of human monoclonal antibodies by Epstein-Barr virus transformation and somatic cell fusion has been used by many laboratories, however the steps involved have not been fully optimized. B lymphocytes isolated from the peripheral blood of normal donors were enriched for Thomsen-Friedenreich (T) antigen-reactive cells by panning on asialoglycophorin. The EBV-transformed lymphoblastoid cell lines generated from asialoglycophorin-adherent B lymphocytes were treated in three different manners: (1) cloned and maintained in culture as monoclonal lymphoblastoid cell lines, (2) cloned and fused with murine myeloma cells or (3) fused shortly after transfomation without prior cloning. Cloned lymphoblastoid cell lines maintained in culture without fusion either died or lost specific antibody secretion within five months. Uncloned lymphoblastoid cells remained viable for up to three months but lost specific antibody secretion within two months probably due to overgrowth by nonspecific clones. In an attempt to increase longevity and to stabilize specific antibody secretion by these cells, the cloned lymphoblastoid cells were fused with murine myeloma cells. In nine of ten fusions no hybrids were recovered. As an alternate approach, uncloned lymphoblastoid cells secreting T antigen-specific antibody were hybridized with murine myeloma cells, hybrids secreting T antigen-specific antibody were recovered in six of seven fusions. Furthermore, T antigen-specific antibodies of high titer were secreted by the heterohybridoma clones for more than five months of continuous culture. These heterohybridoma cells secreted more immunoglobulin, produced greater titers of antibody and maintained specific antibody secretion longer than either monoclonal or polyclonal EBV-transformed lymphoblastoid cells. These studies have conclusively demonstrated that fusion of polyclonal lymphoblastoid cells secreting T antigen-specific antibody with murine myeloma cells results in prolongation of human monoclonal antibody production compared with unfused monoclonal or polyclonal lymphoblastoid cell lines. This procedure should be generally applicable for the production of stable human monoclonal antibody-secreting cells lines from peripheral blood lymphocytes. ^

Differential Stability of Reciprocal Friendships and Unilateral Relationships Among Preschool Children

It was expected that reciprocal relationships would be maintained more frequently across a six-month interval than would unilateral ones. Of secondary concern was the question of whether the dimensions children offered to justify their friendships would remain more stable for reciprocal than unilateral relationships.

Influence of perylenediimide–pyrene supramolecular interactions on the stability of DNA-based hybrids: Importance of electrostatic complementarity

Aromatic pi–pi stacking interactions are ubiquitous in nature, medicinal chemistry and materials sciences. They play a crucial role in the stacking of nucleobases, thus stabilising the DNA double helix. The following paper describes a series of chimeric DNA–polycyclic aromatic hydrocarbon (PAH) hybrids. The PAH building blocks are electron-rich pyrene and electron-poor perylenediimide (PDI), and were incorporated into complementary DNA strands. The hybrids contain different numbers of pyrene–PDI interactions that were found to directly influence duplex stability. As the pyrene–PDI ratio approaches 1:1, the stability of the duplexes increases with an average value of 7.5 °C per pyrene–PDI supramolecular interaction indicating the importance of electrostatic complementarity for aromatic pi–pi stacking interactions.

ON THE STABILITY OF SUPER-EARTH ATMOSPHERES

We investigate the stability of super-Earth atmospheres around M stars using a seven-parameter, analytical framework. We construct stability diagrams in the parameter space of exoplanetary radius versus semimajor axis and elucidate the regions in which the atmospheres are stable against the condensation of their major constituents, out of the gas phase, on their permanent nightside hemispheres. We find that super-Earth atmospheres that are nitrogen-dominated (Earth-like) occupy a smaller region of allowed parameter space, compared to hydrogen-dominated atmospheres, because of the dual effects of diminished advection and enhanced radiative cooling. Furthermore, some super-Earths which reside within the habitable zones of M stars may not possess stable atmospheres, depending on the mean molecular weight and infrared photospheric pressure of their atmospheres. We apply our stability diagrams to GJ 436b and GJ 1214b, and demonstrate that atmospheric compositions with high mean molecular weights are disfavored if these exoplanets possess solid surfaces and shallow atmospheres. Finally, we construct stability diagrams tailored to the Kepler data set, for G and K stars, and predict that about half of the exoplanet candidates are expected to harbor stable atmospheres if Earth-like conditions are assumed. We include 55 Cancri e and CoRoT-7b in our stability diagram for G stars

Comparison of theoretical fixation stability of three devices employed in medial opening wedge high tibial osteotomy: a finite element analysis.

BACKGROUND Medial open wedge high tibial osteotomy is a well-established procedure for the treatment of unicompartmental osteoarthritis and symptomatic varus malalignment. We hypothesized that different fixation devices generate different fixation stability profiles for the various wedge sizes in a finite element (FE) analysis. METHODS Four types of fixation were compared: 1) first and 2) second generation Puddu plates, and 3) TomoFix plate with and 4) without bone graft. Cortical and cancellous bone was modelled and five different opening wedge sizes were studied for each model. Outcome measures included: 1) stresses in bone, 2) relative displacement of the proximal and distal tibial fragments, 3) stresses in the plates, 4) stresses on the upper and lower screw surfaces in the screw channels. RESULTS The highest load for all fixation types occurred in the plate axis. For the vast majority of the wedge sizes and fixation types the shear stress (von Mises stress) was dominating in the bone independent of fixation type. The relative displacements of the tibial fragments were low (in μm range). With an increasing wedge size this displacement tended to increase for both Puddu plates and the TomoFix plate with bone graft. For the TomoFix plate without bone graft a rather opposite trend was observed.For all fixation types the occurring stresses at the screw-bone contact areas pulled at the screws and exceeded the allowable threshold of 1.2 MPa for at least one screw surface. Of the six screw surfaces that were studied, the TomoFix plate with bone graft showed a stress excess of one out of twelve and without bone graft, five out of twelve. With the Puddu plates, an excess stress occurred in the majority of screw surfaces. CONCLUSIONS The different fixation devices generate different fixation stability profiles for different opening wedge sizes. Based on the computational simulations, none of the studied osteosynthesis fixation types warranted an intransigent full weight bearing per se. The highest fixation stability was observed for the TomoFix plates and the lowest for the first generation Puddu plate. These findings were revealed in theoretical models and need to be validated in controlled clinical settings.