Optimal control of the silicon-based donor electron spin quantum computing

We demonstrate how gradient ascent pulse engineering optimal control methods can be implemented on donor electron spin qubits in Si semiconductors with an architecture complementary to the original Kane's proposal. We focus on the high-fidelity controlled-NOT (CNOT) gate and explicitly find its digitized control sequences by optimizing its fidelity over the external controls of the hyperfine A and exchange J interactions. This high-fidelity CNOT gate has an error of about $10^{-6}$, below the error threshold required for fault-tolerant quantum computation, and its operation time of 100ns is about 3 times faster than 297ns of the proposed global control scheme. It also relaxes significantly the stringent distance constraint of two neighboring donor atoms of 10~20nm as reported in the original Kane's proposal to about 30nm in which surface A and J gates may be built with current fabrication technology. The effects of the control voltage fluctuations, the dipole-dipole interaction and the electron spin decoherence on the CNOT gate fidelity are also discussed.Comment: 4 figures, accepted as a Rapid Communication by Phys. Rev.

Differential evolutionary conservation of motif modes in the yeast protein interaction network

BACKGROUND: The importance of a network motif (a recurring interconnected pattern of special topology which is over-represented in a biological network) lies in its position in the hierarchy between the protein molecule and the module in a protein-protein interaction network. Until now, however, the methods available have greatly restricted the scope of research. While they have focused on the analysis in the resolution of a motif topology, they have not been able to distinguish particular motifs of the same topology in a protein-protein interaction network. RESULTS: We have been able to assign the molecular function annotations of Gene Ontology to each protein in the protein-protein interactions of Saccharomyces cerevisiae. For various motif topologies, we have developed an algorithm, enabling us to unveil one million "motif modes", each of which features a unique topological combination of molecular functions. To our surprise, the conservation ratio, i.e., the extent of the evolutionary constraints upon the motif modes of the same motif topology, varies significantly, clearly indicative of distinct differences in the evolutionary constraints upon motifs of the same motif topology. Equally important, for all motif modes, we have found a power-law distribution of the motif counts on each motif mode. We postulate that motif modes may very well represent the evolutionary-conserved topological units of a protein interaction network. CONCLUSION: For the first time, the motifs of a protein interaction network have been investigated beyond the scope of motif topology. The motif modes determined in this study have not only enabled us to differentiate among different evolutionary constraints on motifs of the same topology but have also opened up new avenues through which protein interaction networks can be analyzed

Comparison and prediction of pullout strength of conical and cylindrical pedicle screws within synthetic bone

<p>Abstract</p> <p>Background</p> <p>This study was designed to derive the theoretical formulae to predict the pullout strength of pedicle screws with an inconstant outer and/or inner diameter distribution (conical screws). For the transpedicular fixation, one of the failure modes is the screw loosening from the vertebral bone. Hence, various kinds of pedicle screws have been evaluated to measure the pullout strength using synthetic and cadaveric bone as specimens. In the literature, the Chapman's formula has been widely proposed to predict the pullout strength of screws with constant outer and inner diameters (cylindrical screws).</p> <p>Methods</p> <p>This study formulated the pullout strength of the conical and cylindrical screws as the functions of material, screw, and surgery factors. The predicted pullout strength of each screw was compared to the experimentally measured data. Synthetic bones were used to standardize the material properties of the specimen and provide observation of the loosening mechanism of the bone/screw construct.</p> <p>Results</p> <p>The predicted data from the new formulae were better correlated with the mean pullout strength of both the cylindrical and conical screws within an average error of 5.0% and <it>R</it>²= 0.93. On the other hand, the average error and <it>R</it>²value of the literature formula were as high as -32.3% and -0.26, respectively.</p> <p>Conclusion</p> <p>The pullout strength of the pedicle screws was the functions of bone strength, screw design, and pilot hole. The close correlation between the measured and predicted pullout strength validated the value of the new formulae, so as avoid repeating experimental tests.</p

Hypothermic manipulation of bone cement can extend the handling time during vertebroplasty

BACKGROUND: Polymethylmethacrylate (PMMA) is commonly used for clinical applications. However, the short handling time increases the probability of a surgeon missing the crucial period in which the cement maintains its ideal viscosity for a successful injection. The aim of this article was to illustrate the effects a reduction in temperature would have on the cement handling time during percutaneous vertebroplasty. METHODS: The injectability of bone cement was assessed using a cement compressor. By twisting the compressor, the piston transmits its axial load to the plunger, which then pumps the bone cement out. The experiments were categorized based on the different types of hypothermic manipulation that were used. In group I (room temperature, sham group), the syringes were kept at 22°C after mixing the bone cement. In group 2 (precooling the bone cement and the container), the PMMA powder and liquid, as well as the beaker, spatula, and syringe, were stored in the refrigerator (4°C) overnight before mixing. In group 3 (ice bath cooling), the syringes were immediately submerged in ice water after mixing the bone cement at room temperature. RESULTS: The average liquid time, paste time, and handling time were 5.1 ± 0.7, 3.4 ± 0.3, and 8.5 ± 0.8 min, respectively, for group 1; 9.4 ± 1.1, 5.8 ± 0.5, and 15.2 ± 1.2 min, respectively, for group 2; and 83.8 ± 5.2, 28.8 ± 6.9, and 112.5 ± 11.3 min, respectively, for group 3. The liquid and paste times could be increased through different cooling methods. In addition, the liquid time (i.e. waiting time) for ice bath cooling was longer than for that of the precooling method (p < 0.05). CONCLUSIONS: Both precooling (i.e. lowering the initial temperature) and ice bath cooling (i.e. lowering the surrounding temperature) can effectively slow polymerization. Precooling is easy for clinical applications, while ice bath cooling might be more suitable for multiple-level vertebroplasty. Clinicians can take advantage of the improved injectability without any increased cost

The Processing and Electrical Properties of Isotactic Polypropylene/Copper Nanowire Composites

Funding Information: The authors would like to thank MOST for financially supporting this work under grant No. MOST 110-2224-E-038-001. Publisher Copyright: © 2022 by the authors.Polypropylene (PP), a promising engineering thermoplastic, possesses the advantages of light weight, chemical resistance, and flexible processability, yet preserving insulative properties. For the rising demand for cost-effective electronic devices and system hardware protections, these applications require the proper conductive properties of PP, which can be easily modified. This study investigates the thermal and electrical properties of isotactic polypropylene/copper nanowires (i-PP/CuNWs). The CuNWs were harvested by chemical reduction of CuCl 2 using a reducing agent of glucose, capping agent of hexadecylamine (HDA), and surfactant of PEG-7 glyceryl cocoate. Their morphology, light absorbance, and solution homogeneity were investigated by SEM, UV-visible spectrophotometry, and optical microscopy. The averaged diameters and the length of the CuNWs were 66.4 ± 16.1 nm and 32.4 ± 11.8 µm, respectively. The estimated aspect ratio (L/D, length-to-diameter) was 488 ± 215 which can be recognized as 1-D nanomaterials. Conductive i-PP/CuNWs composites were prepared by solution blending using p-xylene, then melt blending. The thermal analysis and morphology of CuNWs were characterized by DSC, polarized optical microscopy (POM), and SEM, respectively. The melting temperature decreased, but the crystallization temperature increasing of i-PP/CuNWs composites were observed when increasing the content of CuNWs by the melt blending process. The WAXD data reveal the coexistence of Cu 2O and Cu in melt-blended i-PP/CuNWs composites. The fit of the electrical volume resistivity (ρ) with the modified power law equation: ρ = ρ o (V - Vc) -t based on the percolation theory was used to find the percolation concentration. A low percolation threshold value of 0.237 vol% and high critical exponent t of 2.96 for i-PP/CuNWs composites were obtained. The volume resistivity for i-PP/CuNWs composite was 1.57 × 10 7 Ω-cm at 1 vol% of CuNWs as a potential candidate for future conductive materials.publishersversionPeer reviewe

Quantitative measures of functional outcomes and quality of life in patients with C5 palsy

AbstractBackgroundIt is generally understood that postoperative C5 palsy can occur with anterior or posterior decompression surgery, but functional measures of the palsy have not been well documented. This study aimed to investigate the incidence of C5 palsy in different surgical procedures, examine the correlations between muscle strength, upper extremity functional measures, and health-related quality of life, and to observe potential risk factors contributing to C5 palsy.MethodsOur investigation involved a retrospective study design. A total of 364 patients who underwent decompression surgery were indicated within the selected exclusion criteria. Additionally, 12 C5 palsy patients were recruited. The relationships between the manual muscle test (MMT), the action research arm test (ARAT), the Jebsen test of hand function (JTHF), and the European quality of life-5 dimensions (EQ-5D) were studied, and univariate analyses were performed to search possible risk factors and recovery investigation.ResultsThe data analyzed in the 12 cases and C5 palsy incidences (3.3%) were: 0.7% in anterior procedures (n = 2), 8.8% in posterior procedures (n = 6), and 36.4% in combined procedures (n = 4). Moderate-to-high correlations were observed between the ARAT, JTHF, EQ-5D visual analog scale scores, and MMT (r = 0.636–0.899). There were significant differences in patient age, etiology of cervical lesion, variable decompression procedures, and the number of decompression levels between the C5 palsy and non-C5 palsy groups. For female patients (p = 0.018) and number of decompression levels (p = 0.028), there were significant differences between the complete recovery and the incomplete recovery groups.ConclusionPatients undergoing combined anterior–posterior decompression surgery had the highest incidence of C5 palsy, and correlations between the ARAT, JTHF, EQ-5D visual analog scale clinical tools, and MMT scores supported these findings. Female status and lower decompression levels could also be predictive factors for complete recovery, although additional research is needed to substantiate these findings

Osseous wound repair under inhibition of the axis of advanced glycation end-products and the advanced glycation end-products receptor

Background/PurposeBlockade of advanced glycation end-products (AGE) is able to reduce diabetic complications and control periodontitis. This study aimed to determine whether the application of aminoguanidine (AG), an AGE inhibitor, or N-phenacylthiazolium bromide (PTB), an AGE breaker, facilitates the healing of an osseous wound in non-diabetic animals.Methods2.6 mm diameter full-thickness osseous wounds were created bilaterally in 54 healthy Sprague–Dawley rats. Rats received daily normal saline, AG, or PTB injections respectively and were euthanized after 7 days, 14 days, or 28 days (n = 6). The wound healing pattern was assessed by micro-computed tomography, histology, histochemistry for the fiber arrangement, and the gene expression levels of AGE receptor, tumor necrosis factor-α, type I collagen, and fibronectin.ResultsUnder the AG and PTB administration, osteogenesis was apparently promoted in the early stages of healing, but the union of the osseous wound and the fibril re-arrangement was apparently retarded. No significant difference was found in any of the micro-computed tomography parameters as compared to the control in the first 14 days, whereas the relative bone volume was significantly higher in the control at Day 28. AGE receptor and tumor necrosis factor-α were depressed in the PTB group, but only temporarily at Day 14 in the AG group. Therefore, at Day 14, type I collagen was significantly upregulated in the PTB group, and fibronectin was significantly increased in the AG group.ConclusionAnti-AGE agents reduced inflammation but did not apparently facilitate osteogenesis during the osseous wound repair

Associations between walking parameters and subsequent sleep difficulty in older adults:a 2-year follow-up study

Purpose: This 2-year follow-up study aimed to examine the associations between total volume, frequency, duration, and speed of walking with subsequent sleep difficulty in older adults. Methods: A total of 800 older adults aged 65 years and over participated in the first survey in 2012 and 511 of them were followed 2 years later. The 5-item Athens Insomnia Scale (AIS-5) was used to measure sleep difficulty. Frequency, duration, and speed of outdoor walking were self-reported. Walking speed was assigned a metabolic equivalent value (MET) from 2.5 to 4.5. Total walking volume in MET-h/week was calculated as frequency × duration × speed. Negative binomial regressions were performed to examine the associations between volume and components of walking with subsequent sleep difficulty with covariates of age, sex, education, marital status, living arrangement, smoking, alcohol consumption, mental health, Charlson Index, exercise (excluding walking), and sleep difficulty at baseline. Results: Participants with low walking volume had a higher level of sleep difficulty 2 years later compared with those with high walking volume (incident rate ratios = 1.61, p = 0.004). When speed, frequency, and duration of walking were simultaneously entered into 1 model, only walking speed was significantly associated with subsequent sleep difficulty (after the model was adjusted for covariates and baseline sleep difficulty). Sensitivity analyses showed that walking duration emerged as a significant predictor among 3 walking parameters, with 2-year changes of sleep scores as dependent variable. Conclusion: Total amount of walking (especially faster walking and lasting for more than 20 min) is associated with less subsequent sleep difficulty after 2 years among older adults