Probing entanglement in a 2D hard-core Bose-Hubbard lattice.

Entanglement and its propagation are central to understanding many physical properties of quantum systems1-3. Notably, within closed quantum many-body systems, entanglement is believed to yield emergent thermodynamic behaviour4-7. However, a universal understanding remains challenging owing to the non-integrability and computational intractability of most large-scale quantum systems. Quantum hardware platforms provide a means to study the formation and scaling of entanglement in interacting many-body systems8-14. Here we use a controllable 4 × 4 array of superconducting qubits to emulate a 2D hard-core Bose-Hubbard (HCBH) lattice. We generate superposition states by simultaneously driving all lattice sites and extract correlation lengths and entanglement entropy across its many-body energy spectrum. We observe volume-law entanglement scaling for states at the centre of the spectrum and a crossover to the onset of area-law scaling near its edges.

Author Correction: Impact of ionizing radiation on superconducting qubit coherence.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Waveguide quantum electrodynamics with superconducting artificial giant atoms.

Models of light-matter interactions in quantum electrodynamics typically invoke the dipole approximation1,2, in which atoms are treated as point-like objects when compared to the wavelength of the electromagnetic modes with which they interact. However, when the ratio between the size of the atom and the mode wavelength is increased, the dipole approximation no longer holds and the atom is referred to as a 'giant atom'2,3. So far, experimental studies with solid-state devices in the giant-atom regime have been limited to superconducting qubits that couple to short-wavelength surface acoustic waves4-10, probing the properties of the atom at only a single frequency. Here we use an alternative architecture that realizes a giant atom by coupling small atoms to a waveguide at multiple, but well separated, discrete locations. This system enables tunable atom-waveguide couplings with large on-off ratios3 and a coupling spectrum that can be engineered by the design of the device. We also demonstrate decoherence-free interactions between multiple giant atoms that are mediated by the quasi-continuous spectrum of modes in the waveguide-an effect that is not achievable using small atoms11. These features allow qubits in this architecture to switch between protected and emissive configurations in situ while retaining qubit-qubit interactions, opening up possibilities for high-fidelity quantum simulations and non-classical itinerant photon generation12,13.

Impact of ionizing radiation on superconducting qubit coherence.

Technologies that rely on quantum bits (qubits) require long coherence times and high-fidelity operations1. Superconducting qubits are one of the leading platforms for achieving these objectives2,3. However, the coherence of superconducting qubits is affected by the breaking of Cooper pairs of electrons4-6. The experimentally observed density of the broken Cooper pairs, referred to as quasiparticles, is orders of magnitude higher than the value predicted at equilibrium by the Bardeen-Cooper-Schrieffer theory of superconductivity7-9. Previous work10-12 has shown that infrared photons considerably increase the quasiparticle density, yet even in the best-isolated systems, it remains much higher10 than expected, suggesting that another generation mechanism exists13. Here we provide evidence that ionizing radiation from environmental radioactive materials and cosmic rays contributes to this observed difference. The effect of ionizing radiation leads to an elevated quasiparticle density, which we predict would ultimately limit the coherence times of superconducting qubits of the type measured here to milliseconds. We further demonstrate that radiation shielding reduces the flux of ionizing radiation and thereby increases the energy-relaxation time. Albeit a small effect for today's qubits, reducing or mitigating the impact of ionizing radiation will be critical for realizing fault-tolerant superconducting quantum computers.

Beta-blocker use and breast cancer outcomes: a meta-analysis.

PURPOSE: Beta blockers (BBs) are commonly used cardiovascular medications, and their association with breast cancer outcomes has been examined in several previous observational studies and meta-analyses. In this study, an updated meta-analysis was undertaken to ascertain the association between BBs and both breast cancer death (BCD) and breast cancer recurrence (BCR). METHODS: Articles were sourced from various databases up until the 14th of August 2023. Effect estimates were pooled using the random effects model, and the Higgins I2 statistic was computed to ascertain heterogeneity. Subgroup analyses were conducted by the potential for immortal time bias (ITB), the exposure period (prediagnosis vs postdiagnosis), and type of BB (selective vs non-selective). Publication bias was assessed using funnel plots and Egger's regression tests. RESULTS: Twenty-four studies were included. Pooled results showed that there was no statistically significant association between BB use and both BCD (19 studies, hazard ratio = 0.90, 95% CI 0.78-1.04) and BCR (16 studies, HR = 0.87, 95% CI 0.71-1.08). After removing studies with ITB, the associations were attenuated towards the null. There was no effect modification for either outcome when stratifying by the exposure period or type of BB. There was clear evidence of publication bias for both outcomes. CONCLUSION: In this meta-analysis, we found no evidence of an association between BB use and both BCD and BCR. Removing studies with ITB attenuated the associations towards the null, but there was no effect modification by the exposure period or type of BB.

Ultrasound assessment of humeral shaft nonunion risk: a feasibility and proof of concept study.

PURPOSE: To determine the feasibility and reliability of ultrasound in the assessment of humeral shaft fracture healing and estimate the accuracy of 6wk ultrasound in predicting nonunion. METHODS: Twelve adults with a non-operatively managed humeral shaft fracture were prospectively recruited and underwent ultrasound scanning at 6wks and 12wks post-injury. Seven blinded observers evaluated sonographic callus appearance to determine intra- and inter-observer reliability. Nonunion prediction accuracy was estimated by comparing images for patients that united (n = 10/12) with those that developed a nonunion (n = 2/12). RESULTS: The mean scan duration was 8 min (5-12) and all patients tolerated the procedure. At 6wks and 12wks, sonographic callus (SC) was present in 11 patients (10 united, one nonunion) and sonographic bridging callus (SBC) in seven (all united). Ultrasound had substantial intra- (weighted kappa: 6wk 0.75; 12wk 0.75) and inter-observer reliability (intraclass correlation coefficient: 6wk 0.60; 12wk 0.76). At 6wks, the absence of SC demonstrated sensitivity 50%, specificity 100%, positive predictive value (PPV) 100% and negative predictive value (NPV) 91% in nonunion prediction (overall accuracy 92%). The absence of SBC demonstrated sensitivity 100%, specificity 70%, PPV 40% and NPV 100% in nonunion prediction (overall accuracy 75%). Of three patients at risk of nonunion (Radiographic Union Score for HUmeral fractures < 8), one had SBC on 6wk ultrasound (that subsequently united) and the others had non-bridging/absent SC (both developed nonunion). CONCLUSIONS: Ultrasound assessment of humeral shaft fracture healing was feasible, reliable and may predict nonunion. Ultrasound could be useful in defining nonunion risk among patients with reduced radiographic callus formation.

Post-diagnostic statin use and breast cancer-specific mortality: a population-based cohort study.

PURPOSE: Statins are the most widely prescribed cholesterol lowering medications and have been associated with both improved and unchanged breast cancer outcomes in previous studies. This study examines the association between the post-diagnostic use of statins and breast cancer outcomes (death and recurrence) in a large, representative sample of New Zealand (NZ) women with breast cancer. METHODS: Women diagnosed with a first primary breast cancer between 2007 and 2016 were identified from four population-based regional NZ breast cancer registries and linked to national pharmaceutical data, hospital discharges, and death records. Cox proportional hazard models were used to estimate the hazard of breast cancer-specific death (BCD) associated with any post-diagnostic statin use. RESULTS: Of the 14,976 women included in analyses, 27% used a statin after diagnosis and the median follow up time was 4.51 years. Statin use (vs non-use) was associated with a statistically significant decreased risk of BCD (adjusted hazard ratio: 0.74; 0.63-0.86). The association was attenuated when considering a subgroup of 'new' statin users (HR: 0.91; 0.69-1.19), however other analyses revealed that the protective effect of statins was more pronounced in estrogen receptor positive patients (HR: 0.77; 0.63-0.94), postmenopausal women (HR: 0.74; 0.63-0.88), and in women with advanced stage disease (HR: 0.65; 0.49-0.84). CONCLUSION: In this study, statin use was associated with a statistically significant decreased risk of breast cancer death, with subgroup analyses revealing a more protective effect in ER+ patients, postmenopausal women, and in women with advanced stage disease. Further research is warranted to determine if these associations are replicated in other clinical settings.

Hexagonal boron nitride as a low-loss dielectric for superconducting quantum circuits and qubits.

Dielectrics with low loss at microwave frequencies are imperative for high-coherence solid-state quantum computing platforms. Here we study the dielectric loss of hexagonal boron nitride (hBN) thin films in the microwave regime by measuring the quality factor of parallel-plate capacitors (PPCs) made of NbSe2-hBN-NbSe2 heterostructures integrated into superconducting circuits. The extracted microwave loss tangent of hBN is bounded to be at most in the mid-10-6 range in the low-temperature, single-photon regime. We integrate hBN PPCs with aluminium Josephson junctions to realize transmon qubits with coherence times reaching 25 µs, consistent with the hBN loss tangent inferred from resonator measurements. The hBN PPC reduces the qubit feature size by approximately two orders of magnitude compared with conventional all-aluminium coplanar transmons. Our results establish hBN as a promising dielectric for building high-coherence quantum circuits with substantially reduced footprint and with a high energy participation that helps to reduce unwanted qubit cross-talk.

Evolution of 1/f Flux Noise in Superconducting Qubits with Weak Magnetic Fields.

The microscopic description of 1/f magnetic flux noise in superconducting circuits has remained an open question for several decades despite extensive experimental and theoretical investigation. Recent progress in superconducting devices for quantum information has highlighted the need to mitigate sources of qubit decoherence, driving a renewed interest in understanding the underlying noise mechanism(s). Though a consensus has emerged attributing flux noise to surface spins, their identity and interaction mechanisms remain unclear, prompting further study. Here, we apply weak in-plane magnetic fields to a capacitively shunted flux qubit (where the Zeeman splitting of surface spins lies below the device temperature) and study the flux-noise-limited qubit dephasing, revealing previously unexplored trends that may shed light on the dynamics behind the emergent 1/f noise. Notably, we observe an enhancement (suppression) of the spin-echo (Ramsey) pure-dephasing time in fields up to B=100 G. With direct noise spectroscopy, we further observe a transition from a 1/f to approximately Lorentzian frequency dependence below 10 Hz and a reduction of the noise above 1 MHz with increasing magnetic field. We suggest that these trends are qualitatively consistent with an increase of spin cluster sizes with magnetic field. These results should help to inform a complete microscopic theory of 1/f flux noise in superconducting circuits.

Differential attainment in higher surgical training: scoping pan-specialty spectra.

INTRODUCTION: This study aimed to evaluate differential attainment during higher surgical training (HST; all specialties) related to three ethnic cohorts: White UK (WUKG), Black and Minority Ethnic UK Graduates (BMEUKG), and International Medical Graduates (IMG). METHOD: Anonymised records of 266 HSTs (126 WUKG, 65 BMEUKG, 75 IMG; 7 years) in a single UK Statutory Education Body were examined. Primary effect measures were Annual Record of Competency Progression Outcome (ARCPO) and Fellowship of the Royal College of Surgeons (FRCS) pass. RESULTS: ARCPOs related to ethnicity and specialty were similar with the exception of general surgery (GS) trainees, four of whom received ARCPO 4 (GS 4.9% (75% BME; p=0.025) vs all other 0%). ARCPO 3 was commoner in women (22/76, (28.9%) than men 27/190 (14.2%), OR 2.46, p=0.006). FRCS pass rates (WUKG vs BMEUKG vs IMG) were 76.9%, 52.9% and 53.9% respectively (p=0.064) but unrelated to gender (M 70.4% vs F 64.3%). On multivariable analyses: ARCPO 3 was associated with Female gender and Maternity Leave (OR 8.05, p=0.001); FRCS pass with ethnicity (OR 0.21, p=0.028) and Hirsch Indices of ≥5 (OR 11.17, p=0.001). CONCLUSION: Differential attainment was plain with BMEUKG FRCS performance almost a third poorer than WUKG, and women twofold more likely to receive adverse ARCPOs, with return from statutory leave independently associated with training extension. Focused counter measures targeted at non-operative technical skills (including academic reach), Keeping in Touch, Return to Work, and re-induction programmed support are urgently needed for trainees at risk.

The Radiographic Union Score for ulnar fractures (RUSU) predicts ulnar shaft nonunion.

AIMS: To develop a reliable and effective radiological score to assess the healing of isolated ulnar shaft fractures (IUSF), the Radiographic Union Score for Ulna fractures (RUSU). METHODS: Initially, 20 patients with radiographs six weeks following a non-operatively managed ulnar shaft fracture were selected and scored by three blinded observers. After intraclass correlation (ICC) analysis, a second group of 54 patients with radiographs six weeks after injury (18 who developed a nonunion and 36 who united) were scored by the same observers. RESULTS: In the initial study, interobserver and intraobserver ICC were 0.89 and 0.93, respectively. In the validation study, the interobserver ICC was 0.85. The median score for patients who united was significantly higher than those who developed a nonunion (11 vs. 7, p < 0.001). A ROC curve demonstrated that a RUSU ≤ 8 had a sensitivity of 88.9% and specificity of 86.1% in identifying patients at risk of nonunion. Patients with a RUSU ≤ 8 (n = 21) were more likely to develop a nonunion (n = 16/21) than those with a RUSU ≥ 9 (n = 2/33; OR 49.6, 95% CI 8.6-284.7). Based on a PPV of 76%, if all patients with a RUSU ≤ 8 underwent fixation at 6 weeks, the number of procedures needed to avoid one nonunion would be 1.3. CONCLUSION: The RUSU shows good interobserver and intraobserver reliability and is effective in identifying patients at risk of nonunion six weeks after fracture. This tool requires external validation but may enhance the management of patients with isolated ulnar shaft fractures.

Distal radius malunion: outcomes following an ulnar shortening osteotomy.

PURPOSE: Positive ulnar variance following a distal radius malunion can lead to ulnar-sided wrist pain, loss of grip strength, and distal radioulnar joint impingement. The primary aim of this study is to describe upper limb-specific functional outcomes following ulnar shortening osteotomy (USO) for ulnar-sided wrist pain associated with malunion of the distal radius. METHODS: We retrospectively identified 40 adult patients from a single centre over a 9-year period that had undergone an USO for symptomatic malunion of the distal radius. The primary outcome was the patient-rated wrist evaluation (PRWE). Secondary outcomes were the QuickDASH, EQ-5D-5L, complications, and net promoter score (NPS). RESULTS: Outcomes were available for 37 patients (93%). The mean age was 56 years and 25 patients were female (68%). At a mean follow-up of 6 years (range 1-10 years) the median PRWE was 11 (IQR 0-29.5), the median QuickDASH 6.8 (IQR 0-29.5), and the median EQ-5D-5L index was 0.88 (IQR 0.71-1). The NPS was 73. Complications occurred in nine patients (24%) and included non-union (n = 4), early loss of fixation requiring revision surgery (n = 1), superficial wound infection (n = 2), neurological injury (n = 1), and further surgery for symptomatic hardware removal (n = 1). CONCLUSIONS: For patients with a symptomatic distal radius malunion where the predominant deformity is ulnar positive variance, this study has demonstrated that despite 1 in 4 patients experiencing a complication, USO can result in excellent patient reported outcomes with high levels of satisfaction. LEVEL OF EVIDENCE: III (Cohort Study).

Post-diagnostic beta blocker use and breast cancer-specific mortality: a population-based cohort study.

PURPOSE: Beta blockers (BB) have been associated with improved, worsened, or unchanged breast cancer outcomes in previous studies. This study examines the association between the post-diagnostic use of BBs and death from breast cancer in a large, representative sample of New Zealand (NZ) women with breast cancer. METHODS: Women diagnosed with a first primary breast cancer between 2007 and 2016 were identified from four population-based regional NZ breast cancer registries and linked to national pharmaceutical data, hospital discharges, and death records. The median follow-up time was 4.51 years. Cox proportional hazard models were used to estimate the hazard of breast cancer-specific death (BCD) associated with any post-diagnostic BB use. RESULTS: Of the 14,976 women included in analyses, 21% used a BB after diagnosis. BB use (vs non-use) was associated with a small and nonstatistically significant increased risk of BCD (adjusted hazard ratio: 1.11; 95% CI 0.95-1.29). A statistically significant increased risk confined to short-term use (0-3 months) was seen (HR = 1.40; 1.14-1.73), and this risk steadily decreased with increasing duration of use and became a statistically significant protective effect at 3 + years of use (HR = 0.55; 0.34-0.88). CONCLUSION: Our findings suggest that any increased risk associated with BB use may be driven by risk in the initial few months of use. Long-term BB use may be associated with a reduction in BCD.

Global analysis of differential gene expression within the porcine conceptus transcriptome as it transitions through spherical, ovoid, and tubular morphologies during the initiation of elongation.

This study aimed to identify transcriptome differences between distinct or transitional stage spherical, ovoid, and tubular porcine blastocysts throughout the initiation of elongation. We performed a global transcriptome analysis of differential gene expression using RNA-Seq with high temporal resolution between spherical, ovoid, and tubular stage blastocysts at specific sequential stages of development from litters containing conceptus populations of distinct or transitional blastocysts. After RNA-Seq analysis, significant differentially expressed genes (DEGs) and pathways were identified between distinct morphologies or sequential development stages. Overall, 1898 significant DEGs were identified between distinct spherical and ovoid morphologies, with 311 total DEGs between developmental stages throughout this first morphological transition, while 15 were identified between distinct ovoid and tubular, with eight total throughout these second morphological transition developmental stages. The high quantity of DEGs and pathways between conceptus stages throughout the spherical to ovoid transition suggests the importance of gene regulation during this first morphological transition for initiating elongation. Further, extensive DEG coverage of known elongation signaling pathways was illustrated from spherical to ovoid, and regulation of lipid signaling and membrane/ECM remodeling across these early conceptus stages were implicated as essential to this process, providing novel insights into potential mechanisms governing this rapid morphological change.

Revisiting the Temperature Dependence of Protein Diffusion inside Bacteria: Validity of the Stokes-Einstein Equation.

Although the transport and mixing of proteins and other molecules inside bacteria rely on the diffusion of molecules, many aspects of the molecular diffusion in bacterial cytoplasm remain unclear or controversial, including how the diffusion-temperature relation follows the Stokes-Einstein equation. In this study, we applied single-particle tracking photoactivated localization microscopy to investigate the diffusion of histonelike nucleoid structuring (HNS) proteins and free dyes in bacterial cytoplasm at different temperatures. Although the diffusion of HNS proteins in both live and dead bacteria increased at higher temperatures and appeared to follow the Arrhenius equation, the diffusion of free dyes decreased at higher temperatures, questioning the previously proposed theories based on superthermal fluctuations. To understand the measured diffusion-temperature relations, we developed an alternative model, in which the bacterial cytoplasm is considered as a polymeric network or mesh. In our model, the Stokes-Einstein equation remains valid, while the polymeric network contributes a significant term to the viscosity experienced by the molecules diffusing in bacterial cytoplasm. Our model was successful in predicting the diffusion-temperature relations for both HNS proteins and free dyes in bacteria. In addition, we systematically examined the predicted diffusion-temperature relations with different parameters in the model, and predicted the possible existence of phase transitions.

Demonstration of Tunable Three-Body Interactions between Superconducting Qubits.

Nonpairwise multiqubit interactions present a useful resource for quantum information processors. Their implementation would facilitate more efficient quantum simulations of molecules and combinatorial optimization problems, and they could simplify error suppression and error correction schemes. Here, we present a superconducting circuit architecture in which a coupling module mediates two-local and three-local interactions between three flux qubits by design. The system Hamiltonian is estimated via multiqubit pulse sequences that implement Ramsey-type interferometry between all neighboring excitation manifolds in the system. The three-local interaction is coherently tunable over several MHz via the coupler flux biases and can be turned off, which is important for applications in quantum annealing, analog quantum simulation, and gate-model quantum computation.

Yearling bulls have reduced sperm concentration and increased seminal plasma interleukin-8 after a 28-day breeding season.

We hypothesized that yearling bulls selected for a 28-d breeding season would have reduced sperm concentrations and morphology, and have increased seminal plasma concentrations of pro-inflammatory cytokine interleukin-8 (IL-8). Yearling bulls were selected based on a breeding soundness examination (BSE) at approximately 415 d of age and contained at least 750 million sperm in the ejaculate, with 12 bulls randomly selected for breeding (BREEDERS) and 12 bulls not selected for breeding (NON-BREEDERS). After a 28-d breeding period, all bulls underwent a BSE. Plasma and seminal plasma were collected at each time point for analysis. Data were analysed utilizing either the MIXED or GLIMMIX procedures with repeated measures in SAS with breeding group, age and the interaction as fixed effects. Sperm concentration per ml of ejaculate was reduced (p < .05) in yearling bulls used for breeding compared with those not used for breeding at the end of the breeding season. Seminal plasma IL-8 concentrations in yearling bulls used for breeding were increased (p < .05) after the breeding season compared with bulls not used for breeding. Taken together, yearling bulls selected for a 28-d breeding season have reduced sperm production per ml of an ejaculate and increased inflammatory response in the seminal plasma that can lead to impaired breeding response if they are to be used for more than 30 d of breeding.

Taking a Breather: Advances in Interleukin 5 Inhibition for Asthma Relief.

Interleukin 5 (IL-5) is a major cytokine responsible for eosinophil proliferation, migration and degranulation. Eosinophils play a considerable role in the manifestation of type 2 asthma, and therefore this makes IL-5 a unique and clinically important target for therapeutic intervention. Due to the critical role that IL-5 plays in all areas of eosinophil activity, it has been identified and targeted by three therapeutics, Mepolizumab, Benralizumab and Reslizumab. This review describes the IL-5 pathway and presents the clinical trial history of the three IL-5 inhibitors, to provide insight into the role of IL-5 in clinical asthma presentation. Additionally, this review aims to foster further investigation into the IL-5 pathway by describing current novel therapeutic discovery strategies with monoclonal antibodies.

Outcome following mini-open lower limb fasciotomy for chronic exertional compartment syndrome.

PURPOSE: The aim of this study was to report outcomes following mini-open lower limb fasciotomy (MLLF) in active adults with chronic exertional compartment syndrome (CECS). METHODS: From 2013-2018, 38 consecutive patients (mean age 31 years [16-60], 71% [n = 27/38] male) underwent MLLF. There were 21 unilateral procedures, 10 simultaneous bilateral and 7 staged bilateral. There were 22 anterior fasciotomies, five posterior and 11 four-compartment. Early complications were determined from medical records of 37/38 patients (97%) at a mean of four months (1-19). Patient-reported outcomes (including EuroQol scores [EQ-5D/EQ-VAS], return to sport and satisfaction) were obtained via postal survey from 27/38 respondents (71%) at a mean of 3.7 years (0.3-6.4). RESULTS: Complications occurred in 16% (n = 6/37): superficial infection (11%, n = 4/37), deep infection (3%, n = 1/37) and wound dehiscence (3%, n = 1/37). Eight per cent (n = 3/37) required revision fasciotomy for recurrent leg pain. At longer-term follow-up, 30% (n = 8/27) were asymptomatic and another 56% (n = 15/27) reported improved symptoms. The mean pain score improved from 6.1 to 2.5 during normal activity and 9.1 to 4.7 during sport (both p < 0.001). The mean EQ-5D was 0.781 (0.130-1) and EQ-VAS 77 (33-95). Of 25 patients playing sport preoperatively, 64% (n = 16/25) returned, 75% (n = 12/16) reporting improved exercise tolerance. Seventy-four per cent (n = 20/27) were satisfied and 81% (n = 22/27) would recommend the procedure. CONCLUSION: MLLF is safe and effective for active adults with CECS. The revision rate is low, and although recurrent symptoms are common most achieve symptomatic improvement, with reduced activity-related leg pain and good health-related quality of life. The majority return to sport and are satisfied with their outcome.

Factors associated with humeral shaft nonunion.

BACKGROUND: The primary aim was to identify patient and injury factors independently associated with humeral diaphyseal fracture nonunion after nonoperative management. The secondary aim was to determine the effect of management (operative/nonoperative) on nonunion. METHODS: From 2008-2017, a total of 734 humeral shaft fractures (732 consecutive skeletally mature patients) were retrospectively identified from a trauma database. Follow-up was available for 663 fractures (662 patients, 90%) that formed the study cohort. Patient and injury characteristics were recorded. There were 523 patients (79%) managed nonoperatively and 139 (21%) managed operatively. Outcome (union/nonunion) was determined from medical records and radiographs. RESULTS: The median age at injury was 57 (range 16-96) years and 54% (n = 359/662) were female. Median follow-up was 5 (1.2-74) months. Nonunion occurred in 22.7% (n = 119/524) of nonoperatively managed injuries. Multivariate analysis demonstrated preinjury nonsteroidal anti-inflammatory drugs (NSAIDs; odds ratio [OR] 20.58, 95% confidence interval [CI] 2.12-199.48; P = .009) and glenohumeral arthritis (OR 2.44, 95% CI 1.03-5.77; P = .043) were independently associated with an increased risk of nonunion. Operative fixation was independently associated with a lower risk of nonunion (2.9%, n = 4/139) compared with nonoperative management (OR for nonoperative/operative management 9.91, 95% CI 3.25-30.23; P < .001). Based on these findings, 5 patients would need to undergo primary operative fixation in order to avoid 1 nonunion. CONCLUSIONS: Preinjury NSAIDs and glenohumeral arthritis were independently associated with nonunion following nonoperative management of a humeral diaphyseal fracture. Operative fixation was the independent factor most strongly associated with a lower risk of nonunion. Targeting early operative fixation to at-risk patients may reduce the rate of nonunion and the morbidity associated with delayed definitive management.