Explore the vast range of titles available.

The control of material interfaces at the atomic level has led to novel interfacial properties and functionalities. In particular, the study of polar discontinuities at interfaces between complex oxides lies at the frontier of modern condensed matter research. Here we employ a combination of experimental measurements and theoretical calculations to demonstrate the control of a bulk property, namely ferroelectric polarization, of a heteroepitaxial bilayer by precise atomic-scale interface engineering. More specifically, the control is achieved by exploiting the interfacial valence mismatch to influence the electrostatic potential step across the interface, which manifests itself as the biased-voltage in ferroelectric hysteresis loops and determines the ferroelectric state. A broad study of diverse systems comprising different ferroelectrics and conducting perovskite underlayers extends the generality of this phenomenon.

SummaryWe performed a meta-analysis of relevant studies to quantify the magnitude of the association between proton pump inhibitors (PPIs) and risk of hip fracture. Patients with PPIs had a greater risk of hip fracture than those without PPI therapy (RR 1.20, 95% CI 1.14–1.28, p < 0.0001). These results could be taken into consideration with caution, and patients should also be concerned about the inappropriate use of PPIs.IntroductionProton pump inhibitors (PPIs) are generally considered as first-line medicine with great safety profile, commonly prescribed for gastroesophageal reflux disease (GERD) and peptic ulcer disease. However, several epidemiological studies documented that long-term use of PPIs may be associated with an increased risk of hip fracture. Although, the optimal magnitude of the hip fracture risk is still undetermined. We, therefore, performed a meta-analysis of relevant studies to quantify the magnitude of the association between PPIs and risk of hip fracture.MethodsWe collected relevant articles using MEDLINE, EMBASE, Google Scholar, and Web of Science from January 1, 1990, to March 31, 2018. We included only the large (n ≥ 500) observational studies with a follow-up duration of at least one year in which the hip fracture patients were identified by a standard procedure. Two of the authors extracted data from each included study independently according to a standardized protocol.ResultsA total of 24 observational studies with 2,103,800 participants (319,568 hip fracture patients) met all the eligibility criteria. Patients with PPIs had a greater risk of hip fracture than those without PPI therapy (RR 1.20, 95% CI 1.14–1.28, p < 0.0001). An increased association was also observed in both low and medium doses of PPI taken and hip fracture risk (RR 1.17, 95% CI 1.05–1.29, p = 0.002; RR 1.28, 95% CI 1.14–1.44, p < 0.0001), but it appeared to be even greater among the patients with higher dose (RR 1.30, 95% CI 1.20–1.40, p < 0.0001). Moreover, the overall pooled risk ratios were 1.20 (95% CI 1.15–1.25, p < 0.0001) and 1.24 (95% CI 1.10–1.40, p < 0.0001) for the patients with short- and long-term PPI therapy, respectively, compared with PPI non-users.ConclusionOur results suggest that PPI use is significantly associated with an increased risk of hip fracture development, which is not observed in H2RA exposure. Physicians should, therefore, exercise caution when considering a long-term PPI treatment to their patients who already have an elevated risk of hip fracture. In addition, patients should be concerned about the inappropriate use of PPIs; if necessary, then, they should continue to receive it with a clear indication.

Piezoelectric materials, which convert mechanical to electrical energy and vice versa, are typically characterized by the intimate coexistence of two phases across a morphotropic phase boundary. Electrically switching one to the other yields large electromechanical coupling coefficients. Driven by global environmental concerns, there is currently a strong push to discover practical lead-free piezoelectrics for device engineering. Using a combination of epitaxial growth techniques in conjunction with theoretical approaches, we show the formation of a morphotropic phase boundary through epitaxial constraint in lead-free piezoelectric bismuth ferrite (BiFeO3) films. Electric field–dependent studies show that a tetragonal-like phase can be reversibly converted into a rhombohedral-like phase, accompanied by measurable displacements of the surface, making this new lead-free system of interest for probe-based data storage and actuator applications.

Universal quantum computation will require qubit technology based on a scalable platform 1 , together with quantum error correction protocols that place strict limits on the maximum infidelities for one- and two-qubit gate operations 2 , 3 . Although various qubit systems have shown high fidelities at the one-qubit level 4 – 10 , the only solid-state qubits manufactured using standard lithographic techniques that have demonstrated two-qubit fidelities near the fault-tolerance threshold 6 have been in superconductor systems. Silicon-based quantum dot qubits are also amenable to large-scale fabrication and can achieve high single-qubit gate fidelities (exceeding 99.9 per cent) using isotopically enriched silicon 11 , 12 . Two-qubit gates have now been demonstrated in a number of systems 13 – 15 , but as yet an accurate assessment of their fidelities using Clifford-based randomized benchmarking, which uses sequences of randomly chosen gates to measure the error, has not been achieved. Here, for qubits encoded on the electron spin states of gate-defined quantum dots, we demonstrate Bell state tomography with fidelities ranging from 80 to 89 per cent, and two-qubit randomized benchmarking with an average Clifford gate fidelity of 94.7 per cent and an average controlled-rotation fidelity of 98 per cent. These fidelities are found to be limited by the relatively long gate times used here compared with the decoherence times of the qubits. Silicon qubit designs employing fast gate operations with high Rabi frequencies 16 , 17 , together with advanced pulsing techniques 18 , should therefore enable much higher fidelities in the near future. Two-qubit logic gates in a silicon-based system are shown (using randomized benchmarking) to have high gate fidelities of operation and are used to generate Bell states, a step towards solid-state quantum computation.

Quantum computers are expected to outperform conventional computers in several important applications, from molecular simulation to search algorithms, once they can be scaled up to large numbers—typically millions—of quantum bits (qubits) 1 – 3 . For most solid-state qubit technologies—for example, those using superconducting circuits or semiconductor spins—scaling poses a considerable challenge because every additional qubit increases the heat generated, whereas the cooling power of dilution refrigerators is severely limited at their operating temperature (less than 100 millikelvin) 4 – 6 . Here we demonstrate the operation of a scalable silicon quantum processor unit cell comprising two qubits confined to quantum dots at about 1.5 kelvin. We achieve this by isolating the quantum dots from the electron reservoir, and then initializing and reading the qubits solely via tunnelling of electrons between the two quantum dots 7 – 9 . We coherently control the qubits using electrically driven spin resonance 10 , 11 in isotopically enriched silicon 12 28 Si, attaining single-qubit gate fidelities of 98.6 per cent and a coherence time of 2 microseconds during ‘hot’ operation, comparable to those of spin qubits in natural silicon at millikelvin temperatures 13 – 16 . Furthermore, we show that the unit cell can be operated at magnetic fields as low as 0.1 tesla, corresponding to a qubit control frequency of 3.5 gigahertz, where the qubit energy is well below the thermal energy. The unit cell constitutes the core building block of a full-scale silicon quantum computer and satisfies layout constraints required by error-correction architectures 8 , 17 . Our work indicates that a spin-based quantum computer could be operated at increased temperatures in a simple pumped 4 He system (which provides cooling power orders of magnitude higher than that of dilution refrigerators), thus potentially enabling the integration of classical control electronics with the qubit array 18 , 19 . A scalable silicon quantum processor unit cell made of two qubits confined to quantum dots operates at about 1.5 K, achieving 98.6% single-qubit gate fidelities and a 2 μs coherence time.

There is little evidence in the literature about the relationship between frailty and falls in older adults. Our objective was to explore the relationship between frailty and falls, and to analyze the effect factors (e.g., gender, different frailty assessment tools, areas, level of national economic development, and year of publication) of the association between frailty and falls among older adults. Systematic review and meta-analysis. Cohort studies that evaluated the association between frailty and falls in the older adults were included. We excluded any literature outside of cohort studies. We did a systematic literature search of English databases PubMed, Scopus, Web of Science, EBSCOhost, and SciElO, as well as the Chinese databases CNKI, WANFANG, and VIP from 2001 until October 2022. The eligible studies were evaluated for potential bias using the Newcastle-Ottawa Scale (NOS). Study selection, data extraction and assessment of study quality were each conducted by two investigators. In Stata/MP 17.0 software, we calculated pooled estimates of the prevalence of falls by using a random-effects model, Subgroup analysis was conducted based on gender, different frailty assessment tools, areas, level of economic development, and year of publication. The results are presented using a forest plot. Twenty-nine studies were included in this meta-analysis and a total of 1,093,270 participants aged 65 years and above were enrolled. Among the older adults, frailty was significantly associated with a higher risk for falls, compared with those without frailty (combined RR-relative risk = 1.48, 95% CI-confidence interval: 1.27–1.73, I2=98.9%). In addition, the results of subgroup analysis indicated that men had a higher risk for falls than women among the older adults with frailty (RR 1.94, 95% CI: 1.18–3.2 versus RR 1.44, 95% CI: 1.24–1.67). Subgroup analysis by different frailty assessment tools revealed an increased risk of falls in older adults with frailty when assessed using the Frailty Phenotype (combined RR 1.32, 95%CI: 1.17–1.48), FRAIL score (combined RR 1.82, 95%CI: 1.36–2.43), and Study of Osteoporotic Fractures index (combined RR 1.54, 95%CI: 1.10–2.16). Furthermore, subgroup analysis by areas and level of national economic development found the highest fall risk in Oceania (combined RR 2.35, 95%CI: 2.28–2.43) and the lowest in Europe (combined RR 1.20, 95%CI: 1.05–1.38). Developed countries exhibited a lower fall risk compared to developing countries (combined RR 1.44, 95%CI: 1.21–1.71). Analysis by year of publication showed the highest fall risk between 2013–2019 (combined RR 1.79, 95%CI: 1.45–2.20) and the lowest between 2001–2013 (combined RR 1.21, 95%CI: 1.13–1.29). Frailty represents a significant risk factor for falls in older adults, with the degree of risk varying according to the different frailty assessment tools employed, and notably highest when using the FRAIL scale. Additionally, factors such as gender, areas, level of national economic development, and healthcare managers' understanding of frailty may all impact the correlation between frailty and falls. Thus, it's imperative to select suitable frailty diagnostic tools tailored to the specific characteristics of the population in question. This, in turn, facilitates the accurate identification of frailty in older adults and informs the development of appropriate preventive and therapeutic strategies to mitigate fall risk.

We integrated four gene expression profile data sets, namely two different pair-matched stage I lung adenocarcinoma data sets, secondary metastatic tumors vs benign tumors and lung tumor metastasizes to the brain, and we identified one kinase, T-LAK Cell-Originated Protein Kinase (TOPK), as a putative gene that promotes metastasis. To delineate the role of TOPK in lung cancer, we showed that overexpression of TOPK, but not a catalytically inactive form of TOPK, can enhance the migration and invasion of lung fibroblasts or cells with low TOPK expression. In addition, TOPK-induced cell migration was shown to be a PI3K/AKT-dependent event. TOPK concurrently promoted AKT phosphorylation at Ser 473 and decreased the phosphatase and tensin homolog (PTEN) levels, whereas TOPK knockdown had the reverse effects. LY294002, a PI3K inhibitor, did not inhibit the TOPK-induced decrease in PTEN, and co-expression of PTEN significantly reduced TOPK-induced AKT phosphorylation in a dose-dependent manner; these results indicate that the TOPK-mediated PTEN decrease has an upstream role in regulating PI3K/AKT-stimulated migration. Using immunohistochemical analysis of lung cancer tissue samples, we showed that a high TOPK expression level correlates strongly with reduced overall and disease-free survivals. Moreover, an inverse correlation between TOPK and PTEN expression was present and is consistent with the biochemical findings. Finally, a combination of high TOPK and low PTEN expression was inversely correlated with overall and disease-free survivals, independent of other pathologic staging factors. Our results suggest that TOPK is a potential therapeutic target in lung cancer that promotes cell migration by modulating a PI3K/PTEN/AKT-dependent signaling pathway; they also suggest that high TOPK expression, either alone or in combination with a low level of PTEN, may serve as a prognostic marker for lung cancer.

Occurrence of amyloid-β (Aβ) aggregation in brain begins before the clinical onset of Alzheimer’s disease (AD), as preclinical AD. Studies have reported that sleep problems and autonomic dysfunction associate closely with AD. However, whether they, especially the interaction between sleep and autonomic function, play critical roles in preclinical AD are unclear. Therefore, we investigated how sleep patterns and autonomic regulation at different sleep–wake stages changed and whether they were related to cognitive performance in pathogenesis of AD mice. Polysomnographic recordings in freely-moving APP/PS1 and wild-type (WT) littermates were collected to study sleep patterns and autonomic function at 4 (early disease stage) and 8 months of age (advanced disease stage), cognitive tasks including novel object recognition and Morris water maze were performed, and Aβ levels in brain were measured. APP/PS1 mice at early stage of AD pathology with Aβ aggregation but without significant differences in cognitive performance had frequent sleep–wake transitions, lower sleep-related delta power percentage, lower overall autonomic activity, and lower parasympathetic activity mainly during sleep compared with WT mice. The same phenomenon was observed in advanced-stage APP/PS1 mice with significant cognitive deficits. In mice at both disease stages, sleep-related delta power percentage correlated positively with memory performance. At early stage, memory performance correlated positively with sympathetic activity during wakefulness; at advanced stage, memory performance correlated positively with parasympathetic activity during both wakefulness and sleep. In conclusion, sleep quality and distinction between wake- and sleep-related autonomic function may be biomarkers for early AD detection.