Evidence of scaling advantage for the quantum approximate optimization algorithm on a classically intractable problem.

The quantum approximate optimization algorithm (QAOA) is a leading candidate algorithm for solving optimization problems on quantum computers. However, the potential of QAOA to tackle classically intractable problems remains unclear. Here, we perform an extensive numerical investigation of QAOA on the low autocorrelation binary sequences (LABS) problem, which is classically intractable even for moderately sized instances. We perform noiseless simulations with up to 40 qubits and observe that the runtime of QAOA with fixed parameters scales better than branch-and-bound solvers, which are the state-of-the-art exact solvers for LABS. The combination of QAOA with quantum minimum finding gives the best empirical scaling of any algorithm for the LABS problem. We demonstrate experimental progress in executing QAOA for the LABS problem using an algorithm-specific error detection scheme on Quantinuum trapped-ion processors. Our results provide evidence for the utility of QAOA as an algorithmic component that enables quantum speedups.

Bone-level Tapered Implants for Single Tooth Replacement. Immediate vs Delayed Placement: A Randomized, Controlled, Multi-center One-year No-inferiority Clinical Study.

MATERIALS AND METHODS: Post-market, prospective, randomized, controlled, multi-center study with a primary endpoint of one year. 53 subjects were randomized to receive either immediate implant placement (test group) or delayed implant placement (control group). The mean crestal bone-level changes from implant loading to 12 months post-implant loading were measured using standardized, digital periapical radiographs. Changes in facial plate thickness measured on cone-beam computed tomography (CBCT) images, implant success and survival, implant stability, soft tissue changes, patient-centered outcomes, and adverse effects were measured to assess outcomes between the test and control treatments at 12 months post-loading. RESULTS: 46 subjects completed the study (23 in each group). Mean bone changes from loading to the 12 month follow-up were recorded with no statistically significant difference (p=0.950) between both groups. The hypothesis was confirmed that immediate implant placement (Test) in extraction sockets is similar to delayed placement (Control). The test group was found to be similar to the control group (P=0.022) in terms of mean changes in facial plate thickness. Implant survival and success were 95.8% in the test group and 92% in the control group. Stability in the control group was superior at the time of surgery, but there was no difference between both groups at implant loading, producing a non-significant p-value of (0.563). CONCLUSION: This randomized, controlled, multi-center one-year study showed comparable outcomes 1-year after prosthetic loading in the immediate and delayed placement groups.

Non-Abelian topological order and anyons on a trapped-ion processor.

Non-Abelian topological order is a coveted state of matter with remarkable properties, including quasiparticles that can remember the sequence in which they are exchanged1-4. These anyonic excitations are promising building blocks of fault-tolerant quantum computers5,6. However, despite extensive efforts, non-Abelian topological order and its excitations have remained elusive, unlike the simpler quasiparticles or defects in Abelian topological order. Here we present the realization of non-Abelian topological order in the wavefunction prepared in a quantum processor and demonstrate control of its anyons. Using an adaptive circuit on Quantinuum's H2 trapped-ion quantum processor, we create the ground-state wavefunction of D4 topological order on a kagome lattice of 27 qubits, with fidelity per site exceeding 98.4 per cent. By creating and moving anyons along Borromean rings in spacetime, anyon interferometry detects an intrinsically non-Abelian braiding process. Furthermore, tunnelling non-Abelions around a torus creates all 22 ground states, as well as an excited state with a single anyon-a peculiar feature of non-Abelian topological order. This work illustrates the counterintuitive nature of non-Abelions and enables their study in quantum devices.

Remote vision testing of central retinal acuity and comparison with clinic-based Snellen acuity testing in patients followed for retinal conditions.

Introduction: The unmet need for remote monitoring of visual function with home-based, patient-centric technologies became increasingly palpable during the COVID-19 pandemic. Many patients with chronic eye conditions lack access to office-based examinations. Here, we evaluate the efficacy of the Accustat® test, a virtual application for measuring near visual acuity on any portable electronic device via telehealth. Materials and methods: Thirty-three adult subjects from the telehealth remote monitoring service of a retina practice performed the Accustat® acuity testing at home. All patients underwent in-office general eye examination with additional fundoscopic examination and optical coherence tomography retina imaging. Best corrected visual acuity assessment using a Snellen chart was compared with remote visual acuity assessment with the Accustat® test. Visual acuity was analyzed and compared between the best-corrected near visual acuity potential achieved on the Accustat® and in-office distance best-corrected Snellen visual acuity. Results: The mean logarithm of the minimum angle of resolution (logMAR) visual acuities of all eyes tested using the Accustat test was 0.19 ± 024 and for the office Snellen test 0.21 ± 0.21. A linear regression model with 95% confidence intervals reveals that there is a strong linear relationship between Accustat logMAR and office Snellen logMAR. Bland-Altman analysis demonstrated 95.2% significant agreement between Accustat and Office Snellen's best corrected visual acuity. Intraclass correlation coefficient (ICC = 0.94) demonstrated a strong positive correlation between at home versus office visual acuity. Conclusion: There was a high correlation between the visual acuity measured with the Accustat near vision digital self-test and the office Snellen acuity test, suggesting the potential utility of scalable remote monitoring of central retinal function via telehealth.

A 3D printable alloy designed for extreme environments.

Multiprincipal-element alloys are an enabling class of materials owing to their impressive mechanical and oxidation-resistant properties, especially in extreme environments1,2. Here we develop a new oxide-dispersion-strengthened NiCoCr-based alloy using a model-driven alloy design approach and laser-based additive manufacturing. This oxide-dispersion-strengthened alloy, called GRX-810, uses laser powder bed fusion to disperse nanoscale Y2O3 particles throughout the microstructure without the use of resource-intensive processing steps such as mechanical or in situ alloying3,4. We show the successful incorporation and dispersion of nanoscale oxides throughout the GRX-810 build volume via high-resolution characterization of its microstructure. The mechanical results of GRX-810 show a twofold improvement in strength, over 1,000-fold better creep performance and twofold improvement in oxidation resistance compared with the traditional polycrystalline wrought Ni-based alloys used extensively in additive manufacturing at 1,093 °C5,6. The success of this alloy highlights how model-driven alloy designs can provide superior compositions using far fewer resources compared with the 'trial-and-error' methods of the past. These results showcase how future alloy development that leverages dispersion strengthening combined with additive manufacturing processing can accelerate the discovery of revolutionary materials.

Quantitative Biology at Community Colleges, a Network of Biology and Mathematics Faculty Focused on Improving Numerical and Quantitative Skills of Students.

Mastery of quantitative skills is increasingly critical for student success in life sciences, but few curricula adequately incorporate quantitative skills. Quantitative Biology at Community Colleges (QB@CC) is designed to address this need by building a grassroots consortium of community college faculty to 1) engage in interdisciplinary partnerships that increase participant confidence in life science, mathematics, and statistics domains; 2) generate and publish a collection of quantitative skills-focused open education resources (OER); and 3) disseminate these OER and pedagogical practices widely, in turn expanding the network. Currently in its third year, QB@CC has recruited 70 faculty into the network and created 20 modules. Modules can be accessed by interested biology and mathematics educators in high school, 2-year, and 4-year institutions. Here, we use survey responses, focus group interviews, and document analyses (principles-focused evaluation) to evaluate the progress in accomplishing these goals midway through the QB@CC program. The QB@CC network provides a model for developing and sustaining an interdisciplinary community that benefits participants and generates valuable resources for the broader community. Similar network-building programs may wish to adopt some of the effective aspects of the QB@CC network model to meet their objectives.

Wbm0076, a candidate effector protein of the Wolbachia endosymbiont of Brugia malayi, disrupts eukaryotic actin dynamics.

Brugia malayi, a parasitic roundworm of humans, is colonized by the obligate intracellular bacterium, Wolbachia pipientis. The symbiosis between this nematode and bacterium is essential for nematode reproduction and long-term survival in a human host. Therefore, identifying molecular mechanisms required by Wolbachia to persist in and colonize B. malayi tissues will provide new essential information regarding the basic biology of this endosymbiosis. Wolbachia utilize a Type IV secretion system to translocate so-called "effector" proteins into the cytosol of B. malayi cells to promote colonization of the eukaryotic host. However, the characterization of these Wolbachia secreted proteins has remained elusive due to the genetic intractability of both organisms. Strikingly, expression of the candidate Wolbachia Type IV-secreted effector protein, Wbm0076, in the surrogate eukaryotic cell model, Saccharomyces cerevisiae, resulted in the disruption of the yeast actin cytoskeleton and inhibition of endocytosis. Genetic analyses show that Wbm0076 is a member of the family of Wiskott-Aldrich syndrome proteins (WAS [p]), a well-conserved eukaryotic protein family required for the organization of actin skeletal structures. Thus, Wbm0076 likely plays a central role in the active cell-to-cell movement of Wolbachia throughout B. malayi tissues during nematode development. As most Wolbachia isolates sequenced to date encode at least partial orthologs of wBm0076, we find it likely that the ability of Wolbachia to directly manipulate host actin dynamics is an essential requirement of all Wolbachia endosymbioses, independent of host cell species.

Image registration and subtraction in dynamic magnetic resonance lymphangiography (MRL) of the legs.

Dynamic contrast-enhanced magnetic resonance lymphangiography (DCE-MRL) is regularly reported as unable to depict lymphatic vessels in healthy limbs. In this study, we aim to improve lymph vessel conspicuity with appropriate registration and subtraction of a reference baseline image. Five unaffected individuals and a single unilateral primary lymphoedema patient were recruited to undergo fat suppressed 3D T 1 weighted spoiled gradient echo imaging of the lower limbs at 3.0 T. Images were quality assessed by two physicians and a medical physicist following registration via one of six registration pipelines, and subtraction of the first post-contrast dynamic image (PC1). Wilcoxon non-parametric testing was performed to compare image quality ranking vs the unregistered images and inter-rater reliability estimated using intraclass correlation coefficient. Signal enhancement curves were also computed in lymphatic vessels for two participants. Subtraction images were considered to improve lymphatic visibility, and three registration pipelines significantly (p < 0.05) outranked those without registration. Those registered to PC1 with an affine and elastic approach were rated best quality (p = 0.006). Moderate inter-rater reliability was observed (intraclass correlation coefficient = 0.71) and signal enhancement behaviour appears affected by registration when motion is evident across the DCE-MRL series. We therefore conclude that lymphatic vessel visibility in DCE-MRL images can be improved with registration and baseline subtraction.

Remote patient monitoring of central retinal function with MACUSTAT®: A multi-modal macular function scan.

Introduction: There is significant unmet need for patient-centric remote monitoring of visual function for chronic retinal diseases, as demonstrated by the COVID-19 pandemic. The Macustat® central retinal function scan is a novel cloud-based digital health application for remote monitoring. The aim of this study is to assess the efficacy of the Macustat® compared to traditional in-office retinal evaluations. Materials and methods: Patients with underlying macular pathology underwent office-based retinal and visual acuity examinations and OCT macula imaging followed by remote tele-monitoring assessment with the Macustat. Central visual function was assessed with the multi-modal Macustat test using dynamic virtual Amsler grid testing, hyperacuity perimetry and visual acuity testing. The results were compared to the findings of the in-office comprehensive retina exam and OCT evaluation. Results: The foveal acuity potential registered with the Macustat test showed high correlation with the office Snellen acuity potential 96% of eyes registered Macustat acuity within 0.2 LogMAR of office acuity measurement. In Wet AMD eyes with CNV pathology documented on OCT, the Macustat foveal function scan showed a corresponding abnormality in 89% of any CNV eyes and 100% of all visually significant CNV. In normal eyes without any visually significant edema or CNV, more than 92% showed corresponding normal retinal function scan. Conclusion: The Macustat demonstrates high concordance with clinical findings using traditional diagnostic devices. Home monitoring with the Macustat® may offer complementary clinical utility as a telehealth tool for the assessment of visual acuity and macular function in patients at high risk for macular disease.

Enhanced simulated early 21st century Arctic sea ice loss due to CMIP6 biomass burning emissions.

The mechanisms underlying decadal variability in Arctic sea ice remain actively debated. Here, we show that variability in boreal biomass burning (BB) emissions strongly influences simulated Arctic sea ice on multidecadal time scales. In particular, we find that a strong acceleration in sea ice decline in the early 21st century in the Community Earth System Model version 2 (CESM2) is related to increased variability in prescribed BB emissions in the sixth phase of the Coupled Model Intercomparison Project (CMIP6) through summertime aerosol-cloud interactions. Furthermore, we find that more than half of the reported improvement in sea ice sensitivity to CO2 emissions and global warming from CMIP5 to CMIP6 can be attributed to the increased BB variability, at least in the CESM. These results highlight a new kind of uncertainty that needs to be considered when incorporating new observational data into model forcing while also raising questions about the role of BB emissions on the observed Arctic sea ice loss.

The effectiveness of prophylactic antibiotics and betadine skin preparation on cranial cutaneous Cutibacterium acnes - A prospective study.

BACKGROUND: Cutibacterium acnes, formerly known as Propionibacterium acnes, is increasingly recognized as a cause of surgical site infection and implant failure despite the use of prophylactic antibiotics and antiseptic surgical preparations. The aim of this study was to investigate whether C. acnes persists in the dermal layer of the skin after standard perioperative antibiotics and skin prepping with alcoholic betadine solution in consecutive patients undergoing a craniotomy. METHODS: A single centre prospective observational study was performed at Flinders Medical Centre. Adult patients undergoing a cranial neurosurgical intervention between October 2019 to March 2021 were eligible for inclusion. After administration of standard preoperative antibiotics (Cefazolin), three swabs were taken for each patient: one before prepping the skin with alcoholic betadine, one after prepping the skin and a dermal swab once the skin was incised. RESULTS: 73 patients were included. Cutibacterium acnes cultures were positive in 61 patients of the "pre-prep" group (83.6%), 12 (16.4%) in the "post-prep" group, and 53 (72.6%) were from dermal swabs There was a significant reduction of positive cultures of the skin after surgical preparation was applied (p < 0.00001). There was a non-significant reduction of positive cultures in the dermal swabs after skin preparation (p = 0.068) CONCLUSIONS: Cutibacterium acnes persists within the dermis of the scalp despite standard prophylactic measures using alcoholic betadine solution and cefazolin.

Stacking fault energy in concentrated alloys.

We revisit the meaning of stacking fault energy (SFE) and the assumptions of equilibrium dissociation of lattice dislocations in concentrated alloys. SFE is a unique value in pure metals. However, in alloys beyond the dilute limit, SFE has a distribution of values depending on the local atomic environment. Conventionally, the equilibrium distance between partial dislocations is determined by a balance between the repulsive elastic interaction between the partial dislocations and a unique value for SFE. This assumption is used to determine SFE from experimental measurements of dislocation splitting distances in metals and alloys, often contradicting computational predictions. We use atomistic simulations in a model NiCo alloy to study the dislocation dissociation process in a range of compositions with positive, zero, and negative average SFE and surprisingly observe a stable, finite splitting distance in all cases at low temperatures. We then compute the decorrelation stress and examine the balance of forces on the partial dislocations, considering the local effects on SFE, and observe that even the upper bound of SFE distribution alone cannot satisfy the force balance in some cases. Furthermore, we show that in concentrated solid solutions, the resisting force caused by interaction of dislocations with the local solute environment becomes a major force acting on partial dislocations. Here, we show that the presence of a high solute/dislocation interaction, which is not easy to measure and neglected in experimental measurements of SFE, renders the experimental values of SFE unreliable.