Engineering Chiral Light-Matter Interactions in a Waveguide-Coupled Nanocavity.

Spin-dependent, directional light-matter interactions form the basis of chiral quantum networks. In the solid state, quantum emitters commonly possess circularly polarized optical transitions with spin-dependent handedness. We demonstrate numerically that spin-dependent chiral coupling can be realized by embedding such an emitter in a waveguide-coupled nanocavity, which supports two near-degenerate, orthogonally polarized cavity modes. The chiral behavior arises due to direction-dependent interference between the cavity modes upon coupling to two single-mode output waveguides. Notably, an experimentally realistic cavity design simultaneously supports near-unity chiral contrast, efficient (>95%) cavity-waveguide coupling and enhanced light-matter interaction strength (Purcell factor F P > 70). In combination, these parameters enable the development of highly coherent spin-photon interfaces ready for integration into nanophotonic circuits.

Is the Best Plate a Nail? A Review of 3230 Unstable Intertrochanteric Fractures of the Proximal Femur.

OBJECTIVES: To evaluate the functional outcomes, revision, and mortality rates of 3 implants used for unstable intertrochanteric hip fractures; the sliding hip screw (SHS), with or without a trochanteric stabilization plate (TSP); and a cephalomedullary nail (CMN). DESIGN: Multicentre National Prospective Cohort Study. SETTING: Northern Ireland. PATIENT/PARTICIPANTS: Patients were identified from a prospective database. Fractures were classified according to OTA/AO A31A2.2, A2.3, and A3. All patients had a minimum of 12 months of follow-up. INTERVENTION: Patients received either an SHS, an SHS in combination with a TSP, or a CMN. Implant choice was at the discretion of the operating surgeon. OUTCOME MEASURE: Primary outcome was 12-month mortality analyzed by the Kaplan-Meier survival analysis. Secondary outcomes included 12-month functional status using a validated score and all time revision of implants for any reason. RESULTS: In total, 3230 patients met the inclusion criteria (2474 SHS, 158 SHS + TSP, and 598 CMN). CMN use increased over time, with concomitant reduction in SHS use. There was no significant difference in functional outcomes at 12 months (analysis of variance, P = 0.177). Although men were significantly younger, they were at a higher risk of 12-month mortality. CMNs had statistically significantly lower 12-month mortality rates (P = 0.0148). The highest revision rate (4.04%) was seen in patients treated with SHS alone (P = 0.041). CONCLUSIONS: The use of a CMN in unstable intertrochanteric hip fractures conveys the best results in functional outcomes, 12-month mortality, and has lower revision rates compared with an SHS ± TSP. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Fatigue failure of the cephalomedullary nail: revision options, outcomes and review of the literature.

Cephalomedullary nail (CMN) failure is a rare entity following hip fracture treatment. However, it poses significant challenges for revision surgery, both mechanically and biologically. Nail failure rates have been reported at < 2%; however, no published studies have reported revision surgery procedures and their respective outcomes. We present a regional experience, with outcomes, of the revision options. We identified 20 fatigued CMNs that underwent four different revision procedures. Mean age was 73 ± 15.24 years, with a 3:1 female preponderance, and a median ASA grade of 3. Post-operative CMN radiographs demonstrated a significant number of fractures were fixed in varus, with reductions in neck-shaft angles post-operatively. A "poor" quality of reduction resulted in significantly earlier nail failure, compared to "adequate" and "good" (p = 0.027). Tip-Apex Distance (TAD) mean was 23.2 ± 8.3 mm, and an adequate TAD with three-point fixation was seen in only 35% of cases. Mean time to failure was 401.0 ± 237.2 days, with mean age at failure of 74.0 ± 14.8 years. Options after failure included revision CMN nail, proximal femoral locking plate (PFLP), long-stem or restoration arthroplasty, or femoral endoprosthesis. Barthel Functional Index scores showed no significant difference at 3 and 12 months post-operatively, nor any difference between treatment groups. Mean 12-month mortality was 30%, akin to a primary hip fracture mortality risk according to NICE guidelines. Mortality rates were lowest in revision nails. Subsequent revision rates were higher in the PFLP group. There is no reported evidence on the best surgical technique for managing the failed CMN, with no clear functional benefit in the options above. Good surgical technique at the time of primary CMN surgery is critical in minimising fatigue failure. After revision, overall mortality rates were equivalent to reported primary hip fracture mortality rates. Further multicentre evaluations are required to assess which technique convey the best functional outcomes without compromising 12-month mortality rates.

Linearly polarized emission from an embedded quantum dot using nanowire morphology control.

GaAs nanowires with elongated cross sections are formed using a catalyst-free growth technique. This is achieved by patterning elongated nanoscale openings within a silicon dioxide growth mask on a (111)B GaAs substrate. It is observed that MOVPE-grown vertical nanowires with cross section elongated in the [21̅1̅] and [1̅12] directions remain faithful to the geometry of the openings. An InGaAs quantum dot with weak radial confinement is realized within each nanowire by briefly introducing indium into the reactor during nanowire growth. Photoluminescence emission from an embedded nanowire quantum dot is strongly linearly polarized (typically >90%) with the polarization direction coincident with the axis of elongation. Linearly polarized PL emission is a result of embedding the quantum dot in an anisotropic nanowire structure that supports a single strongly confined, linearly polarized optical mode. This research provides a route to the bottom-up growth of linearly polarized single photon sources of interest for quantum information applications.

Periprosthetic femoral fractures--a comparison between cemented and uncemented hemiarthroplasties.

Over a 2-year period, 244 patients underwent hemiarthroplasty for a displaced intracapsular femoral neck fracture. Seventy patients had a cementless Austin-Moore prosthesis (AMP) inserted and 174 patients were treated using a cemented Thompson hemiarthroplasty. All the AMPs were inserted by or under the supervision of an orthopaedic consultant. Five patients (7%) from the AMP group sustained a periprosthetic femoral fracture. Two were iatrogenic and three occurred postoperatively after a simple fall. The fractures occurred proximally around the prosthesis (Johansson type I). Four required revision surgery. There were no periprosthetic femoral fractures in the Thompson group. When compared to the cemented Thompson hemiarthroplasties, the number of periprosthetic femoral fractures was significantly greater with the AMP. Patients in the AMP group were significantly older, although there was no significant difference in ASA grade between the two groups. There was no significant difference in age or gender between those who sustained a periprosthetic fracture and those who did not. These findings suggest that due to the increased risk of periprosthetic femoral fracture, cemented hemiarthroplasty is preferable. Furthermore, with modern cementing techniques, elderly frail patients appear to tolerate bone cement, which may serve to reinforce an osteoporotic proximal femur.