Strong 3p -T1u Hybridization in Ar@C60

Multilayers of fullerenes with and without endohedral Ar units, C60 and Ar@C60, were investigated by photoemission and density functional theory. The stoichiometry and the endohedral nature of Ar is checked by x-ray photoelectron spectroscopy and x-ray photoelectron diffraction. Valence band ultraviolet photoemission spectra show a strong hybridisation of the Ar 3p valence shell with the 6T1u molecular orbital of C60. A hybridisation gap of 1.6 +/- 0.2 eV is found. This is in agreement with density functional theory (DFT) that predicts 1.47 eV, and indicates Ar@C60 to be a noble gas compound with a strong coupling between Ar and the C60 cage. No giant Ar photoemission cross section as predicted for the gas phase in [Phys. Rev. Lett. 99, 243003 (2007)] was found

Resonant Photoelectron Diffraction with circularly polarized light

Resonant angle scanned x-ray photoelectron diffraction (RXPD) allows the determination of the atomic and magnetic structure of surfaces and interfaces. For the case of magnetized nickel the resonant L2 excitation with circularly polarized light yields electrons with a dichroic signature from which the dipolar part may be retrieved. The corresponding L2MM and L3MM Auger electrons carry different angular momenta since their source waves rotate the dichroic dipole in the electron emission patterns by distinct angles

Polycrystalline Yttrium Aluminum Garnet Fibers from Colloidal Sols

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66320/1/j.1151-2916.1995.tb08626.x.pd

A system to measure 3-directional relative displacements for a biomedical application

A micro system for measuring the relative displacements between a bone and an implant in a prosthetic hip of a human being has been realized. Novel are the small dimensions of the system combined with the possibility to measure relative displacements in three directions. The system consists of a microsensor body, a mechanical transducer element made by precision mechanics, electronics, and the final package. The realization and test results of a prototype system are presented. Typical ranges for these prototypes are ±500 μm for lateral directions and ±50 μm in axial direction

Effect of Thin-Film Adhesives on Mode I Interlaminar Fracture Toughness in Carbon Fiber Composites with Shape Memory Alloy Inserts

A single sheet of NiTi shape memory alloy (SMA) was introduced within a unidirectional HexPly 8552/IM7 (Hexcel) polymer matrix composite (PMC) panel in conjunction with multiple thin-film adhesives to promote the interfacial bond strength between the SMA and PMC. A double cantilever beam (DCB) test was performed in accordance with the ASTM D5528 method for evaluation of Mode I interlaminar fracture toughness of unidirectional fiber-reinforced PMCs. The modal acoustic emissions (MAEs) were monitored during testing with two acoustic sensors attached to the specimens. The composite panels were subjected to a C-scan before testing and examined using optical and scanning electron microscopy (SEM) techniques after part failure. The data were used in conjunction with modified beam theory (MBT), the compliance calibration (CC) method, and the modified compliance calibration (MCC) method. The Mode I interlaminar toughness (G(sub IC)) values for control specimens were higher than previously reported and are attributed to extensive fiber bridging during testing. The presence of adhesives with SMA inserts stabilized crack propagation during DCB testing. The results reveal a new phenomenon of SMA bridging, whereby crack propagation would switch from one side of the SMA insert to the other, thus increasing the load and G(sub IC) values of specimens containing SMA

An operative approach to address severe genu valgum deformity in the Ellis-van Creveld syndrome

BACKGROUND: The genu valgum deformity seen in the Ellis-van Creveld syndrome is one of the most severe angular deformities seen in any orthopaedic condition. It is likely a combination of a primary genetic-based dysplasia of the lateral portion of the tibial plateau combined with severe soft-tissue contractures that tether the tibia into valgus deformations. Progressive weight-bearing induces changes, accumulating with growth, acting on the initially distorted and valgus-angulated proximal tibia, worsening the deformity with skeletal maturation. The purpose of this study is to present a relatively large case series of a very rare condition that describes a surgical technique to correct the severe valgus deformity in the Ellis-van Creveld syndrome by combining extensive soft-tissue release with bony realignment. METHODS: 1. Complete proximal to distal surgical decompression of the peroneal nerve. 2. Radical release and mobilization of the severe quadriceps contracture and iliotibial band contracture. 3. Distal lateral hamstring lengthening/tenotomy and lateral collateral ligament release. 4. Proximal and distal realignment of the subluxed/dislocated patella, medial and lateral retinacular release, vastus medialis advancement, patellar chondroplasty, medial patellofemoral ligament plication, and distal patellar realignment by Roux-Goldthwait technique or patellar tendon transfer with tibial tubercle relocation. 5. Proximal tibial varus osteotomy with partial fibulectomy and anterior compartment release. 6. Occasionally, distal femoral osteotomy. RESULTS: In all cases, the combination of radical soft-tissue release, patellar realignment and bony osteotomy resulted in 10° or less of genu valgum at the time of surgical correction. Complications of surgery included three patients (five limbs) with knee stiffness that was successfully manipulated, one peroneal nerve palsy, one wound slough and hematoma requiring a skin graft, and one pseudoarthrosis requiring removal of hardware and repeat fixation. At last follow-up, radiographic correction of no more than 20° of genu valgum was maintained in all but four patients (four limbs). Two patients (three limbs) had or currently require revision surgery due to recurrence of the deformity. CONCLUSION: The operative approach presented in this study has resulted in correction of the severe genu valgum deformity in Ellis-van Creveld syndrome to 10° or less of genu valgum at the time of surgery. Although not an outcomes study, a correction of no more than 20° genu valgum has been maintained in many of the cases included in the study. Further clinical follow-up is still warranted. LEVEL OF EVIDENCE: IV

Total hip replacement. Results of a postal survey of current practice on the cement fixation of the acetabular cup in the UK

Previous finite element studies and laboratory investigations on reconstructed acetabulum joints show that long-term fixation of the acetabular cup in total hip replacements (THRs) is influenced by surgical fixation techniques. The aim of this study is to determine and understand the reasons of current practice in the cement fixation of the acetabular cup in THRs in the UK. Following a pilot study, a postal survey was carried out among 1350 orthopaedic consultants. Response rate was 40% and data obtained from the returned questionnaires provided information about the current practice of 431 consultants with an average of 16.5 years of experience and who perform an average of 55 cemented THR operations annually. The survey showed wide variations in the fixation methods of the acetabular component. 95% of the respondents use cement to fix the acetabular cup, 46% maintain the subchondral bone and 63 % use a flanged acetabular cup. The numbers of anchorage holes drilled vary from zero to thirty-six and drill diameters vary from 2 to 15 mm. Anchorage hole depths vary from 3 to 20 mm. Given the variability of surgical fixation methods, further studies need to be carried out to determine how fixation techniques could be improved to increase the longevity of the acetabular component in THRs. Further investigations could lead to a better understanding of the factors that contribute to the stability of THRs

Stresses in cement mantles of hip replacements: effect of femoral implant sizes, body mass index and bone quality

The effects of femoral prosthetic heads of diameters 22 and 28 mm were investigated on the stability of reconstructed hemi-pelves with cement mantles of thicknesses 1-4 mm and different bone qualities. Materialise medical imaging package and I-Deas finite element (FE) software were used to create accurate geometry of a hemi-pelvis from CT-scan images. Our FE results show an increase in cement mantle stresses associated with the larger femoral head. When a 22 mm femoral head is used on acetabulae of diameters 56 mm and above, the probability of survivorship can be increased by creating a cement mantle of at least 1 mm thick. However, when a 28 mm femoral head is used, a cement mantle thickness of at least 4 mm is needed. Poor bone quality resulted in an average 45% increase in the tensile stresses of the cement mantles, indicating resulting poor survivorship rate