First Indirect Detection Constraints on Axions in the Solar Basin.

Axions with masses of order keV can be produced in great abundance within the Solar core. The majority of Sun-produced axions escape to infinity, but a small fraction of the flux is produced with speeds below the escape velocity. Over time, this process populates a basin of slow-moving axions trapped on bound orbits. These axions can decay to two photons, yielding an observable signature. We place the first limits on this solar basin of axions using recent quiescent solar observations made by the NuSTAR x-ray telescope. We compare three different methodologies for setting constraints, and obtain world-leading limits for axions with masses between 5 and 30 keV, in some cases improving on stellar cooling bounds by more than an order of magnitude in coupling.

New Constraints on Dark Photon Dark Matter with Superconducting Nanowire Detectors in an Optical Haloscope.

Uncovering the nature of dark matter is one of the most important goals of particle physics. Light bosonic particles, such as the dark photon, are well-motivated candidates: they are generally long-lived, weakly interacting, and naturally produced in the early universe. In this work, we report on Light A^{'} Multilayer Periodic Optical SNSPD Target, a proof-of-concept experiment searching for dark photon dark matter in the eV mass range, via coherent absorption in a multilayer dielectric haloscope. Using a superconducting nanowire single-photon detector (SNSPD), we achieve efficient photon detection with a dark count rate of ∼6×10^{-6} counts/s. We find no evidence for dark photon dark matter in the mass range of ∼0.7-0.8 eV with kinetic mixing ε≳10^{-12}, improving existing limits in ε by up to a factor of 2. With future improvements to SNSPDs, our architecture could probe significant new parameter space for dark photon and axion dark matter in the meV to 10 eV mass range.

First Constraints on Nuclear Coupling of Axionlike Particles from the Binary Neutron Star Gravitational Wave Event GW170817.

Light axion fields, if they exist, can be sourced by neutron stars due to their coupling to nuclear matter, and play a role in binary neutron star mergers. We report on a search for such axions by analyzing the gravitational waves from the binary neutron star inspiral GW170817. We find no evidence of axions in the sampled parameter space. The null result allows us to impose constraints on axions with masses below 10^{-11} eV by excluding the ones with decay constants ranging from 1.6×10^{16} to 10^{18} GeV at a 3σ confidence level. Our analysis provides the first constraints on axions from neutron star inspirals, and rules out a large region in parameter space that has not been probed by the existing experiments.

Inferomedial cortical bone contact and fixation with calcar screws on the dynamic and static mechanical stability of proximal humerus fractures.

BACKGROUND: This study aimed to explore the effect of retaining inferomedial cortical bone contact and fixation with calcar screws on the dynamic and static mechanical stability of proximal humerus fractures treated with a locking plate. METHODS: Twelve Synbone prosthetic humeri (SYNBONE-AG, Switzerland) were used for a wedge osteotomy model at the proximal humerus, in four groups. In the cortex contact + screw fixation group and cortex contact group, the inferomedial cortical bone contact was retained. In the screw fixation group and control group, the inferomedial cortical bone contact was not retained. Calcar screw fixation was implemented only in the screw fixation groups. The dynamic and static mechanical stability of the models were tested with dynamic fatigue mechanics testing, quasi-static axial compression, three-point bending, and torsion testing. RESULTS: The cortex contact + screw fixation group showed the longest fatigue life and the best stability. There was 35% difference in fatigue life between the cortex contact + screw fixation group and the cortex contact group, 43%between the cortex contact + screw fixation group and screw fixation group, and 63% between the cortex contact + screw fixation group and screw fixation group (P < 0.01). The cortex contact + screw fixation group showed the best axial compressive stiffness, bending stiffness, and torsion stiffness; these were successively decreased in the other three groups (P < 0.01). CONCLUSION: Retaining inferomedial cortical bone contact and fixation with two calcar screws maintained fracture stability with the highest strength and minimum deformation. Of the two methods, restoration of the inferomedial cortical bone support showed better dynamic and static biomechanical properties than placement of calcar screws alone.

Comparison of the efficacy of a distal clavicular locking plate versus a clavicular hook plate in the treatment of unstable distal clavicle fractures and a systematic literature review.

PURPOSE: The purpose of this study was to retrospectively compare and review the clinical outcomes between the distal clavicular locking plate and clavicular hook plates in the treatment of unstable distal clavicle fractures; moreover, the relevant literature of the two fixation methods was reviewed systematically to identify the non-union, complications, or functional scores, according to the treatment methods and determine which treatment method is better. METHODS: Sixty-six patients with 66 unstable distal clavicle fractures who underwent open reduction and internal fixation with either a distal clavicular locking plate (36 patients) or a clavicular hook plate (30 patients ) were evaluated. The main outcome comparisons included Constant score, rate of non-union, rate of complication, and rate of returning to work three months postoperatively. RESULTS: No significant difference was found between locking plate and hook plate groups in union rate and Constant score (P > 0.05). However, the results indicated that the distal clavicular locking plate group had a significantly lower rate of complications (P < 0.05) and symptomatic hardware (P < 0.05). In addition, the distal clavicular locking plate facilitated the return to work better than the clavicular hook plate (P < 0.05). CONCLUSIONS: Both distal clavicular locking plate and clavicular hook plate achieved good results in the treatment of unstable distal clavicle fractures; however, internal fixation with a distal clavicular locking plate had greater ability to return to their previous work after surgery in three months and fewer complications than the clavicular hook plate.

[The use of minimally invasive injectable graft and internal fixation in tibial plateau fractures].

OBJECTIVE: To value the use of an injectable minimally invasive calcium sulfate cement for displaced tibial plateau fractures. METHODS: Thirteen patients with lateral tibial plateau fractures treated with internal fixation and bone grafting were matched with 13 patients treated using internal fixation and an injectable calcium sulfate cement. The clinical data were retrospectively analyzed. All patients were followed up for a minimum of one year. The peri-operative complication, quality of reduction, maintenance of reduction, function assessment and development of post-traumatic osteoarthritis was compared in both groups. RESULTS: Ten patients in the internal fixation and bone graft group had excellent anatomical reductions as judged on immediate post-operative radiographs but some loss of reduction on follow-up at one year was observed in 8 of the 13 (61%) cases. Twelve patients from the MIIG group had an excellent reduction on immediate post-operative radiographs but 3 (23%)demonstrated some loss of reduction of the plateau at one year follow-up (P < 0.05). CONCLUSIONS: The use of MIIG and internal fixation is associated with more favourable clinical results than conventional treatment with internal fixation and bone grafting for lateral tibial plateau fractures.

[Percutaneous reduction and fixation of osteoporotic fractures for the proximal humerus in a geriatric population].

OBJECTIVE: To appraise the value of clinical treatment of percutaneous reduction and fixation of osteoporotic fractures for the proximal humerus in a geriatric population. METHODS: Postoperation complication, mortality in hospital and within the first three months postoperation, operation time, blood transfusion requirement, the functional outcome of the shoulder had been analysed and observed in 37 cases for open and closed fixation. RESULTS: Closed reduction provided the benefit of obtaining and holding adequate reduction without the soft-tissue dissection of open reduction and internal fixation. The general complication and mortality in the first three months postoperation in the open reduction and internal fixation cases were more severe than the percutaneous cases. CONCLUSIONS: Open operation increases the risk of the geriatric population with osteoporotic proximal humerus fracture; percutaneous reduction and fixation may be preferable.