Removing leakage-induced correlated errors in superconducting quantum error correction.

Quantum computing can become scalable through error correction, but logical error rates only decrease with system size when physical errors are sufficiently uncorrelated. During computation, unused high energy levels of the qubits can become excited, creating leakage states that are long-lived and mobile. Particularly for superconducting transmon qubits, this leakage opens a path to errors that are correlated in space and time. Here, we report a reset protocol that returns a qubit to the ground state from all relevant higher level states. We test its performance with the bit-flip stabilizer code, a simplified version of the surface code for quantum error correction. We investigate the accumulation and dynamics of leakage during error correction. Using this protocol, we find lower rates of logical errors and an improved scaling and stability of error suppression with increasing qubit number. This demonstration provides a key step on the path towards scalable quantum computing.

Diabatic Gates for Frequency-Tunable Superconducting Qubits.

We demonstrate diabatic two-qubit gates with Pauli error rates down to 4.3(2)×10^{-3} in as fast as 18 ns using frequency-tunable superconducting qubits. This is achieved by synchronizing the entangling parameters with minima in the leakage channel. The synchronization shows a landscape in gate parameter space that agrees with model predictions and facilitates robust tune-up. We test both iswap-like and cphase gates with cross-entropy benchmarking. The presented approach can be extended to multibody operations as well.

Strain effect on orbital and magnetic structures of Mn ions in epitaxial Nd0.35Sr0.65MnO3/SrTiO3 films using X-ray diffraction and absorption.

This study probes the temperature-dependent strain that is strongly correlated with the orbital and magnetic structures of epitaxial films of Nd0.35Sr0.65MnO3 (NSMO) that are fabricated by pulsed laser deposition with two thicknesses, 17 (NS17) and 103 nm (NS103) on SrTiO3 (STO) substrate. This investigation is probed using X-ray diffraction (XRD) and absorption-based techniques, X-ray linear dichroism (XLD) and the X-ray magnetic circular dichroism (XMCD). XRD indicates a significant shift in the (004) peak position that is associated with larger strain in NS17 relative to that of NS103 at both 30 and 300 K. Experimental and atomic multiplet simulated temperature-dependent Mn L3,2-edge XLD results reveal that the stronger strain in a thinner NS17 film causes less splitting of Mn 3d eg state at low temperature, indicating an enhancement of orbital fluctuations in the band above the Fermi level. This greater Mn 3d orbital fluctuation can be the cause of both the enhanced ferromagnetism (FM) as a result of spin moments and the reduced Néel temperature of C-type antiferromagnetism (AFM) in NS17, leading to the FM coupling of the canted-antiferromagnetism (FM-cAFM) state in NSMO/STO epitaxial films at low temperature (T = 30 K). These findings are also confirmed by Mn L3,2-edge XMCD measurements.

Origin of magnetic properties in carbon implanted ZnO nanowires.

Various synchrotron radiation-based spectroscopic and microscopic techniques are used to elucidate the room-temperature ferromagnetism of carbon-doped ZnO-nanowires (ZnO-C:NW) via a mild C+ ion implantation method. The photoluminescence and magnetic hysteresis loops reveal that the implantation of C reduces the number of intrinsic surface defects and increases the saturated magnetization of ZnO-NW. The interstitial implanted C ions constitute the majority of defects in ZnO-C:NW as confirmed by the X-ray absorption spectroscopic studies. The X-ray magnetic circular dichroism spectra of O and C K-edge respectively indicate there is a reduction in the number of unpaired/dangling O 2p bonds in the surface region of ZnO-C:NW and the C 2p-derived states of the implanted C ions strongly affect the net spin polarization in the surface and bulk regions of ZnO-C:NW. Furthermore, these findings corroborate well with the first-principles calculations of C-implanted ZnO in surface and bulk regions, which highlight the stability of implanted C for the suppression and enhancement of the ferromagnetism of the ZnO-C:NW in the surface region and bulk phase, respectively.

Recombinant ApxIV protein enhances protective efficacy against Actinobacillus pleuropneumoniae in mice and pigs.

AIMS: Available bacterins, commercial or autogenous, for Actinobacillus pleuropneumoniae disease control have, thus far, shown debatable protective efficacy and only in homologous challenges. Our study sought to determine whether the addition of reombinant protein ApxIV to the multicomponent vaccine could enhance protection against homologous and heterologous challenge of A. pleuropneumoniae. METHODS AND RESULTS: The virulence of ApxI, ApxII, ApxIV and OMP were cloned and expressed using a prokaryotic system; these recombinant proteins were combined with inactivated A. pleuropneumoniae serovar 1 to formulate different multicomponent vaccines. Immune response and protective efficacy of the vaccines were evaluated in mice and pigs. A protection rate of 67% was observed against heterologous challenge in mice vaccinated with the rApxIV formulation. Piglets vaccinated with vaccine containing ApxIV produced significantly higher antibody titre and provided complete protection and reduced gross lesions by 67% when compared with the nonimmunized group after homologous challenge. Additionally, flow cytometry analysis showed significant cellular immune response. CONCLUSIONS: The results of our vaccination experiments revealed that a combination of inactivated bacteria and the recombinant antigens rApxI, rApxII, rApxIV and rOMP can provide effective protection against heterologous A. pleuropneumoniae challenge. SIGNIFICANCE AND IMPACT OF THE STUDY: The addition of ApxIV to the multicomponent vaccine could enhance homologous and heterologous protection in mice and pigs, respectively, against challenge by A. pleuropneumoniae.

Bottom-Up Copper Filling of Large Scale Through Silicon Vias for MEMS Technology.

An electrodeposition process for void-free bottom-up filling of sub-millimeter scale through silicon vias (TSVs) with Cu is detailed. The 600 µm deep and nominally 125 µm diameter metallized vias were filled with Cu in less than 7 hours under potentiostatic control. The electrolyte is comprised of 1.25 mol/L CuSO4 -0.25 mol/L CH3SO3H with polyether and halide additions that selectively suppress metal deposition on the free surface and side walls. A brief qualitative discussion of the procedures used to identify and optimize the bottom-up void-free feature filling is presented.

Should trained lay providers perform HIV testing? A systematic review to inform World Health Organization guidelines.

New strategies for HIV testing services (HTS) are needed to achieve UN 90-90-90 targets, including diagnosis of 90% of people living with HIV. Task-sharing HTS to trained lay providers may alleviate health worker shortages and better reach target groups. We conducted a systematic review of studies evaluating HTS by lay providers using rapid diagnostic tests (RDTs). Peer-reviewed articles were included if they compared HTS using RDTs performed by trained lay providers to HTS by health professionals, or to no intervention. We also reviewed data on end-users' values and preferences around lay providers preforming HTS. Searching was conducted through 10 online databases, reviewing reference lists, and contacting experts. Screening and data abstraction were conducted in duplicate using systematic methods. Of 6113 unique citations identified, 5 studies were included in the effectiveness review and 6 in the values and preferences review. One US-based randomized trial found patients' uptake of HTS doubled with lay providers (57% vs. 27%, percent difference: 30, 95% confidence interval: 27-32, p < 0.001). In Malawi, a pre/post study showed increases in HTS sites and tests after delegation to lay providers. Studies from Cambodia, Malawi, and South Africa comparing testing quality between lay providers and laboratory staff found little discordance and high sensitivity and specificity (≥98%). Values and preferences studies generally found support for lay providers conducting HTS, particularly in non-hypothetical scenarios. Based on evidence supporting using trained lay providers, a WHO expert panel recommended lay providers be allowed to conduct HTS using HIV RDTs. Uptake of this recommendation could expand HIV testing to more people globally.

Incidence and risk factors for cystoid macular edema following scleral buckling.

PurposeTo investigate the incidence of cystoid macular edema (CME) after scleral buckling (SB) and verify the possible risk factors of CME.MethodsA retrospective, non-comparative, interventional case series study was conducted. Clinical charts of 130 consecutive patients who were underwent successful SB for primary retinal detachment (RD) from 2009 to 2013 were reviewed. Optical coherence tomography (OCT) was applied to detect CME. Data pertaining to patient demographics, pre- and postoperative visual acuity, surgical procedures, and postoperative OCT findings were recorded. Factors associated with CME were also analyzed.ResultsThe incidence of CME was 9/130 (6.9%). Risk factors for developing CME were older age (non-CME vs CME: 44.8±14.8 vs 57.3±5.3 years, P<0.05), more extensive RD (RD extent by clock hours; non-CME vs CME: 4.61±1.57 vs 5.78±1.39, P<0.05), macular detachment (non-CME vs CME: 51.2 vs 88.9%, P<0.05), and external drainage (non-CME vs CME: 38.8% vs 77.8%, P<0.05). There was no significant difference between patient with and without CME regarding the use of gas tamponade and the lens status. In patients with more extensive RD (macular detachment plus RD of more than 3 clock hours before surgery), 8 of 68 patients had CME after SB and only older age and external drainage factors were associated with CME.ConclusionsThe risk factors associated with CME after SB were older age, more extended RD, macular detachment, and external drainage. External drainage should be used with caution in older patients with more extensive RD.

A solid-state cation exchange reaction to form multiple metal oxide heterostructure nanowires.

Metal oxide nanostructures have been investigated extensively due to their wide range of physical properties; zinc oxide is one of the most promising materials. It exhibits fascinating functional properties and various types of morphologies. In particular, ZnO heterostructures have attracted great attention because their performance can be modified and further improved by the addition of other materials. In this study, we successfully transformed ZnO nanowires (NWs) into multiple ZnO/Al2O3 heterostructure NWs via a solid-state cation exchange reaction. The experiment was carried out in situ via an ultrahigh vacuum transmission electron microscope (UHV-TEM), which was equipped with a video recorder. Moreover, we analyzed the structure and composition of the heterostructure NWs by Cs-corrected STEM equipped with EDS. Based on these experimental results, we inferred a cation exchange reaction ion path model. Additionally, we investigated the defects that appeared after the cation reaction, which resulted from the remaining zinc ions. These multiple heterostructure ZnO/Al2O3 NWs exhibited excellent UV sensing sensitivity and efficiency.

Rhabdomyolysis caused by the moderate CYP3A4 inhibitor fluconazole in a patient on stable atorvastatin therapy: a case report and literature review.

WHAT IS KNOWN AND OBJECTIVE: Rhabdomyolysis is a severe potential adverse drug reaction of statin therapy. We report a case of rhabdomyolysis due to drug-drug interaction (DDI) between atorvastatin and fluconazole and review the literature. CASE SUMMARY: A 70-year-old woman received atorvastatin for hyperlipidaemia without any problem for 4 years. When intravenous fluconazole was added for treating a fungal infection, rhabdomyolysis developed 2 weeks later. Removal of atorvastatin led to the resolution of her rhabdomyolysis. WHAT IS NEW AND CONCLUSION: Our case demonstrates that in some subjects even a moderate CYP3A4 inhibitor such as fluconazole may lead to rhabdomyolysis in subjects receiving a statin.

Size-controllable synthesis of Bi/Bi2O3 heterojunction nanoparticles using pulsed Nd:YAG laser deposition and metal-semiconductor-heterojunction-assisted photoluminescence.

We synthesized Bi/Bi2O3 heterojunction nanoparticles at various substrate temperatures using the pulsed laser deposition (PLD) technique with a pulsed Nd:YAG laser. The Bi/Bi2O3 heterojunction nanoparticles consisted of Bi nanoparticles and Bi2O3 surface layers. The average diameter of the Bi nanoparticles and the thickness of the Bi2O3 surface layer are linearly proportional to the substrate temperature. The heterojunctions between the Bi nanoparticles and Bi2O3 surface layers, which are the metal-semiconductor heterojunctions, can strongly enhance the photoluminescence (PL) of the Bi/Bi2O3 nanoparticles, because the metallic Bi nanoparticles can provide massive free Fermi-level electrons for the electron transitions in the Bi2O3 surface layers. The enhancement of PL emission at room temperature by metal-semiconductor-heterojunctions make the Bi/Bi2O3 heterojunction nanoparticles potential candidates for use in optoelectronic nanodevices, such as light-emitting diodes (LEDs) and laser diodes (LDs).

Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2H-NbSe2.

We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe2 that we measure by scanning tunneling spectroscopic imaging. We show, from the momentum and energy dependence of the quasiparticle interference, that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe2. We demonstrate that, by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wave vector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology and the interactions. In 2H-NbSe2, we use this combination to confirm that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the charge density wave ordering wave vector.

Early statin therapy in patients with acute intracerebral hemorrhage without prior statin use.

BACKGROUND AND PURPOSE: Statin therapy is beneficial for primary and secondary prevention of ischaemic stroke, but its influence in patients with intracerebral hemorrhage (ICH) is unclear. An assessment was made of the effect of early statin therapy on patients with acute ICH. METHODS: Taiwan's National Health Insurance Research Database was screened for patients without prior statin therapy admitted from January to December 2008 for newly diagnosed ICH. Patients taking statins during hospitalization or within 3 months post-discharge were the early statin group (n = 749); patients who were not were the control group (n = 7583). The study end-points were recurrent ICH and all-cause mortality during follow-up. RESULTS: All eligible patients were followed up until 31 December 2010. During the follow-up, 69 (9.2%) patients in the early statin group and 677 (8.9%) control group patients had recurrent ICH. Cox proportional hazards analyses showed that early statin use did not increase the risk of recurrent ICH (adjusted hazard ratio 1.044; 95% confidence interval 0.812-1.341). During the same period, 90 (12.0%) of the early statin group and 1519 (20.0%) control group patients died. All-cause mortality was lower in the early statin group (adjusted hazard ratio 0.742; 95% confidence interval 0.598-0.919) than in the control group. Matched propensity score analyses were consistent with findings in Cox proportional hazards analyses. CONCLUSIONS: Early statin group patients with acute ICH did not have a higher recurrent risk of ICH and might have lower all-cause mortality during follow-up. It is concluded that statin therapy might be beneficial for patients with ICH.

Vanishing bile duct syndrome and immunodeficiency preceding the diagnosis of Hodgkin lymphoma.

Vanishing bile duct syndrome (VBDS) in association with Hodgkin lymphoma (HL) is well described but not well understood. We report an unusual case of a 75-year-old patient presenting with biopsy-proven VBDS and immunodeficiency, without identifiable cause, which showed a waxing and waning course, culminating in the development of HL 18 months later. To our knowledge, this is the first adult case in which VBDS preceded the diagnosis of HL by such a long period.

Impact of early statin therapy in patients with ischemic stroke or transient ischemic attack.

BACKGROUND: Statin therapy has demonstrated benefits in ischemic stroke patients. However, little is known about whether the timing of statin initiation affects clinical outcomes. The possible association of statin use and cerebral hemorrhage is also a concern for early statin therapy after stroke. The objective of this study was to evaluate the efficacy and safety of the initiation timing of statins in acute ischemic stroke. METHODS: A cohort study was performed using 5-year National Health Insurance Research Database in Taiwan. Patients without prior statin therapy admitted for their new ischemic stroke or transient ischemic attack (TIA) were enrolled. Patients were recognized as inhospital use group (2019 patients, statin initiation during hospitalization), intermediate use group (2266 patients, statin initiation within 1 year after discharge) or late use group (2958 patients, statin initiation 1 year later after discharge). The study endpoint was the composite outcome of ischemic stroke, TIA, hemorrhagic stroke, or acute coronary event. RESULTS: As compared with inhospital use, patients with late use had a 49% increased risk (adjusted HR: 1.49, 95% CI: 1.26-1.76) of composite endpoint. In contrast, patients with intermediate use had similar risk of endpoint as those with inhospital use. The risk of cerebral hemorrhage was similar in patients receiving inhospital, intermediate, or late statin treatment. CONCLUSIONS: In acute ischemic stroke, patients receiving late statin treatment carried a poorer clinical outcome than those with earlier statin initiation. Inhospital statin use after an acute ischemic stroke did not increase the risk of cerebral hemorrhage.

The relationship between umbilical cord arterial pH and serious adverse neonatal outcome: analysis of 51,519 consecutive validated samples.

OBJECTIVE: To examine the relationship between umbilical cord pH at term and serious neonatal outcomes. DESIGN: Observational cohort study. SETTINGS: Deliveries within the Oxford Radcliffe Hospital NHS Trust between 1991 and 2009. POPULATION: In all, 51,519 singleton, term, nonanomalous live neonates with validated umbilical cord arterial pH values. METHODS: Absolute risks, relative risks with 95% confidence intervals, and numbers needed to harm were calculated for different levels of arterial pH across the entire range. MAIN OUTCOME MEASURES: Neonatal encephalopathy with seizures and/or death, encephalopathy within 24 hours of birth, 5-minute Apgar scores and neonatal unit admission. RESULTS: The median arterial pH was 7.22, interquartile range 7.17-7.27. The absolute risk of an adverse neurological outcome was significantly increased below 7.10 (0.36%) and was lowest between 7.26 and 7.30 (0.16%). Even below 7.00, the risk was only 2.95%. However, more than 75% of neonates with neurological outcomes examined, including seizures within 24 hours of birth, had a pH above 7.10. A small increase in risk was evident at higher pH levels. CONCLUSION: The threshold pH for adverse neurological outcomes is 7.10 and the 'ideal' cord pH is 7.26-7.30. Above 7.00, however, neonatal acidaemia is weakly associated with adverse outcomes. Most neonates with neurological morbidity have normal cord pH values. Other variables must influence adverse outcomes and account for more of these than acidaemia. A better understanding of these is required before intrapartum fetal monitoring can improve.

Distribution, reabsorption, and complications of preretinal blood under silicone oil after vitrectomy for severe proliferative diabetic retinopathy.

PURPOSE: To examine the evolution and complications of preretinal hemorrhage under silicone oil after diabetic vitrectomy. METHODS: A total of 44 cases of primary diabetic vitrectomy with silicone oil infusion were reviewed in a 3-year period. Intravitreal bevacizumab was used preoperatively for cases with active proliferation, and in all cases at the end of surgery. Intraoperative bleeding, postoperative extent of preretinal hemorrhage, blood reabsorption time, and reproliferation and treatment results were assessed. RESULTS: Maximal blood distributed in thin and scattered patterns (23 cases), thick and localized patterns (10 cases), or thick and scattered patterns (10 cases) developed within 1 week after surgery, and was largely reabsorbed within a month with improved postoperative vision. Confluent blood extending to the midperiphery (one case) resulted in severe fibrosis and detachment. Complications included fibrotic plaque (two cases), and fibrous band and thick membrane (seven cases). Six cases underwent preretinal tissue removal. Vision improvement ≥ 3 lines was noted in three cases. CONCLUSION: Most of the rebleeding occurred within the first post-op week, with gradual reabsorption in the posterior pole within 4 weeks; widespread confluent bleeding might result in severe reproliferation and detachment. A major complication of preretinal bleeding was the formation of preretinal fibrosis. Re-operation achieved a mild VA improvement.

Effect of statin treatment on three-month outcomes in patients with stroke-associated infection: a prospective cohort study.

BACKGROUND AND PURPOSE: Infection is a major medical problem in patients with acute stroke. Recent evidences suggest that statins reduce infection-associated complications. The purpose of this study was to examine the influence of statin treatment on mortality and functional outcomes in patients with stroke-associated infection. METHODS: In this prospective observational cohort study, 514 patients with acute ischaemic stroke or transient ischaemic attack (mean age, 74 ± 11 years; men, 48%) with infection occurring in the first 7 days after admission were included. We examined the effect of in-hospital statin treatment on mortality and favorable functional outcome (modified Rankin Scale score ≤2) at 3 months follow-up. RESULTS: Infection occurred at 0.93 ± 1.49 days after admission. All patients had not received statin treatment prior to admission, and 121 patients (24%) received statin at 1.71 ± 1.28 days after admission. Follow-up at 3 months was completed for 511 patients (99%). National Institutes of Health Stroke Scale score and Charlson index were the most important independent predictors of mortality and functional outcome. Univariate [hazard ratio (HR), 0.82; 95% confidence intervals (CI), 0.47-1.42] and multivariate (HR, 1.68; 95% CI, 0.79-3.56) Cox regression analysis showed that statin did not significantly decrease the morality. In propensity analysis, statin treatment still had no significant association with mortality (HR, 1.54; 95% CI, 0.68-3.47) in the multivariate analyses after adjusting for age, sex, and propensity score. CONCLUSIONS: Statin use was not associated with a better functional outcome or survival in patients with stroke-associated infection.

High risk of cross-reactivity between vancomycin and sequential teicoplanin therapy.

WHAT IS KNOWN AND OBJECTIVE: Teicoplanin and vancomycin show similar clinical and bacteriological efficacy in clinical trials. Teicoplanin has been reported to have a lower adverse drug reaction (ADR) rate than vancomycin. Cross-reactivity between these two glycopeptides is controversial. Our aim was to study the cross-reactivity between teicoplanin and vancomycin through an assessment of all the reported ADRs of these drugs in our University hospital. METHODS: Over a period of 2 years, 170 cases of vancomycin therapy, which were closely monitored by doctors and clinical pharmacists, were used to analyse ADRs. Teicoplanin therapy was used as an alternative in cases of vancomycin intolerance. When an ADR related to vancomycin or teicoplanin was suspected, specialists were consulted to confirm if these were true ADR and to determine whether the implicated drug should be stopped. All ADRs for the two glycopeptides were assessed for causality using the Naranjo probability scale. RESULTS AND DISCUSSION: Thirty-eight of 170 patients (22·4%) treated with vancomycin developed ADRs. Twenty-four patients were switched to teicoplanin. However, 14 of those 24 patients (58·3%) developed ADRs. The time of onset of ADRs involving vancomycin was 12·7 ± 10·9 days (range, 1-46 days). The time of onset of sequential teicoplanin-induced ADRs was 11·7 ± 4·7 days (range, 2-20 days). Of the 14 patients with ADRs related to sequential teicoplanin therapy, six showed cross-reactivity between vancomycin and teicoplanin. The incidence of vancomycin-induced neutropenia was 4·7% (8/170), whereas the incidence of teicoplanin-induced neutropenia subsequent to vancomycin intolerance was as high as 33·3% (8/24). Furthermore, 71·4% (10/14) of the teicoplanin-induced ADRs were associated with haematological abnormalities such as neutropenia, thrombocytopenia or leucopenia. WHAT IS NEW AND CONCLUSION: Teicoplanin, used as an alternative in cases of vancomycin intolerance, was associated with a high incidence of ADRs and haematological reactions, most notably neutropenia. This high rate of ADRs suggests cross-reactivity between the two glycopeptides.

Teicoplanin-induced hypersensitivity syndrome with a preceding vancomycin-induced neutropenia: a case report and literature review.

Hypersensitivity syndrome associated with teicoplanin has rarely been reported. We report a case with a preceding episode of vancomyin-related neutropenia. A 47-year-old female with cervical spine infection was treated with vancomycin. Neutropenia occurred after 17 days of vancomycin therapy. Vancomycin was changed to teicoplanin, and the neutropenia resolved 4 days later. After 11 days of teicoplanin therapy, a new episode of hypersensitivity syndrome manifested as fever, bilateral neck lymphadenopathy, mild wheezing, hepatitis and increased CRP occurred. Neutropenia and thrombocytopenia developed 3 days later. The patient's symptoms settled over 1 week following withdrawal of teicoplanin. Naranjo's ADR algorithm categorized the neutropenia associated with vancomycin and the hypersensitivity syndrome associated with teicoplanin as 'probable'.