Evolution without standing genetic variation: change in transgenerational plastic response under persistent predation pressure.

Transgenerational phenotypic plasticity is a fast non-genetic response to environmental modifications that can buffer the effects of environmental stresses on populations. However, little is known about the evolution of plasticity in the absence of standing genetic variation although several non-genetic inheritance mechanisms have now been identified. Here we monitored the pea aphid transgenerational phenotypic response to ladybird predators (production of winged offspring) during 27 generations of experimental evolution in the absence of initial genetic variation (clonal multiplication starting from a single individual).

Interaction rewiring and the rapid turnover of plant-pollinator networks.

Whether species interactions are static or change over time has wide-reaching ecological and evolutionary consequences. However, species interaction networks are typically constructed from temporally aggregated interaction data, thereby implicitly assuming that interactions are fixed. This approach has advanced our understanding of communities, but it obscures the timescale at which interactions form (or dissolve) and the drivers and consequences of such dynamics.

Development of a non-invasive diagnostic technique for acetabular component loosening in total hip replacements.

Current techniques for diagnosing early loosening of a total hip replacement (THR) are ineffective, especially for the acetabular component. Accordingly, new, accurate, and quantifiable methods are required. The aim of this study was to investigate the viability of vibrational analysis for accurately detecting acetabular component loosening.

Investigation of an acoustic-mechanical method to detect implant loosening.

Precise diagnosis of loosening of endoprosthetic implants plays an important role in timely, adequate treatment. However, today's diagnostic tools, mainly radiological evaluation, do not yield satisfactory results. Therefore, a new approach based on the transmission of an internally generated combined acoustic and vibration signal, was investigated.

The effects of ozone gas application on shear bond strength of orthodontic brackets to enamel.

Purpose: To investigate the possibility that ozone may have an adverse effect on the bond strength of orthodontic brackets and to determine the area of residual adhesive on teeth after the debonding of brackets.

Methods: 60 extracted premolars teeth were used in this study. Resin coated APC brackets (3M) were bonded according to the manufacturers' instructions.

Immediate functional loading of single-tooth TiO2 grit-blasted implant restoration. A controlled prospective study in a porcine model. Part II: Histology and histomorphometry.

Background: Evidently, there is a fast-moving shift from delayed to immediate implant loading. The hypothesis to be tested was that bone reactions adjacent to single TiO2-microthreaded implants exposed to immediate masticatory loading for 10 weeks after placement would modulate osseointegration.

Materials And Methods: Cylindrical- and tapered-designed implants (Astra Tech AB, Mölndal, Sweden) replaced first and third mandibular premolars respectively in 12 pigs.

Immediate functional loading of single-tooth TIO2 grit-blasted implant restorations: a controlled prospective study in a porcine model. Part I: Clinical outcome.

Background: Although favorable integration occurs with immediately loaded implants, the relationship between implant outcome, levels of occlusion, and diet requires optimization.

Purpose: Pertubating load on single implant restorations immediately after placement by a hard food diet will increase the strains at the bone-implant interface, increasing the risk for failure.

Materials And Methods: Forty-eight implants replaced the first and third mandibular premolars in 12 pigs, allocated into two groups based on soft- and hard-diet feeding.

Investigation of cancellous bone architecture using structural optimisation.

The optimality of bone's internal architecture and its remodelling is investigated by applying topological optimisation. The os-calcis (heel bone) which is subject to a relatively simple loading environment was used as the test problem. The solution is compared with X-ray and CT images of the os-calcis and is demonstrated to agree favourably with the bone's typical trabecular orientation in the coronal plane.

Ultrasound transmission loss across transverse and oblique bone fractures: an in vitro study.

An axial transmission technique has been used to investigate the changes in the first arrival time and signal amplitude of 200 kHz ultrasonic waves travelling across different fracture geometries. Results taken from intact bovine femora were compared with those produced when a transverse and an oblique fracture were simulated. The arrival time and signal amplitude displayed a different variation with receiver position for the two geometries and a given fracture gap width.

A brief history of total ankle replacement and a review of the current status.

Total ankle replacement (TAR) was first attempted in the early 1970s, but poor early results lead to it being abandoned in favour of arthrodesis. Arthrodesis is not totally satisfactory, often causing further hindfoot arthritis and this has lead to a resurgence of interest in joint replacement. New designs which more closely approximated the natural anatomy of the ankle and associated biomechanics have produced more encouraging results and led to renewed interest in total ankle replacement.

Role of hydroxyapatite coating in resisting wear particle migration and osteolysis around acetabular components.

The main problem facing the longevity of total joint replacements is wear particle-induced osteolysis, particularly around the acetabular component. Ovine Total Hip Replacement surgery was performed with roughened femoral heads in order to enhance wear debris generation in vivo. The resistance to aseptic loosening of acetabular components with different surface coatings was investigated.

Mechanical characteristics of antibiotic-laden bone cement.

We studied the mechanical characteristics of cement-antibiotic combinations in vitro. Palacos R was tested without antibiotics, with gentamicin alone and with gentamicin plus vancomycin or flucloxacillin. Palacos LV was studied only with gentamicin added.

Controlled induction of a pseudarthrosis: a study using a rodent model.

Objectives: This study aimed to test the hypothesis that under standardized mechanical and biologic conditions, the process of indirect bone repair in a rodent species could be manipulated to form a reproducible, atrophic, fibrous pseudarthrosis.

Design: The model used comprised a mid-diaphyseal, transverse osteotomy in the rat femur, stabilized via a precision miniature external fixator, a constant axial fixation stiffness being defined by a specific frame geometry.

Main Outcome Measurements: The repair process for both 0.