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In the design of MV AC and DC spacers, the predominant factors are surface and interface conditions. Design is generally carried out on specifications and standards which are based on long-term experience and lab testing. However, the diffusion of power electronics with a trend to increase electric field, switching frequency, and rise time to achieve higher power density calls for an innovative, global approach to optimized insulation system design. A new methodology, based on field simulation, discharge modeling, and partial discharge inception measurements, called the three-leg approach, can form the basis to optimize insulation design for any type of supply voltage waveform. This paper focuses on the influence of the type of electrode on the inception and phenomenology of surface discharges and, as a consequence, on the interpretation of the results used for application of the three-leg approach. It is demonstrated that a typical electrode system used for insulating material testing can generate both gas and surface discharges at the triple point, when the electrodes have a smooth profile that is used to avoid corona or flashover. Hence, testing partial discharge may not provide a straightforward indication of the surface discharge inception and, thus, be partially misleading for insulation design. Another takeover is that such analysis must benefit from PD testing tools endowed with analytics able to provide automatic identification of the type of defect generating PD, i.e., internal, surface, and corona, since design and remedy actions can be taken, and adequate insulating materials developed, only knowing the type of source generating PD. Hence, testing partial discharge may not provide a straightforward indication of surface discharge inception and, thus, be partially misleading for insulation design. In addition to the importance of the three-leg approach to favor reliable and optimized design of insulation systems, there is a clear need to have a PD testing tool endowed with analytics. It should preferably be able to provide automatic identification of the type of defect generating PD, i.e., internal, surface, and corona.

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BACKGROUND: Healed plaques are frequently found in patients with acute coronary syndrome, but the prognostic value is debatable. This study investigated the clinical features of non-culprit healed plaques detected by optical coherence tomography (OCT) with the aim of predicting plaque progression of healed plaques. METHODS: This study retrospectively analyzed 113 non-culprit lesions from 85 patients who underwent baseline OCT imaging and follow-up angiography from January 2015 to December 2019. Plaque progression predictors were assessed by multivariate analysis. RESULTS: Among 113 non-culprit lesions, 27 healed plaques (23.9%) were identified. Patients with non-culprit healed plaques had prior antiplatelet therapy (65.0% vs. 33.8%, P = 0.019), hypertension (85.0% vs. 50.7%, P = 0.009), and dyslipidemia (70.0% vs. 41.5%, P = 0.04) which were more frequently than those without healed plaques. The thickness (r = 0.674, P < 0.001), arc ( r = 0.736, P < 0.001), and volume ( r = 0.541, P = 0.004) of healed plaque were correlated with minimum lumen diameter changes. At a mean follow-up of 11.5 months, the non-culprit healed plaques had a lower minimum lumen diameter (1.61 ± 0.46 mm vs. 1.91 ± 0.73 mm, P = 0.016), lower average lumen diameter (1.86 mm vs. 2.10 mm, P = 0.033), and a higher degree of diameter stenosis (41.4% ± 11.9% vs. 35.5% ± 13.1%, P = 0.031) when compared to baseline measurements. The plaque progression rate was higher in the healed plaque group (33.3% vs. 8.1%, P = 0.002), and multivariate analysis identified healed plaques [odds ratio (OR) = 8.49, 95% CI: 1.71-42.13] and lumen thrombus (OR = 10.69, 95% CI: 2.21-51.71) as predictors of subsequent lesion progression. CONCLUSIONS: Healed plaques were a predictor for rapid plaque progression. The quantitative parameters of healed plaque showed a good agreement with plaque progression. Patients with healed plaque were associated with prior antiplatelet therapy and high level of low-density lipoprotein cholesterol. Bifurcation lesions might be the predilection sites of healed plaques.

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OBJECTIVES: This study aimed to evaluate prognostic value of quantitative flow ratio (QFR) in drug-coated balloon (DCB) angioplasty for in-stent restenosis (ISR). BACKGROUND: There is a high incidence of recurrent ISR after DCB angioplasty. QFR is a novel method for fast computation of fractional flow reserve for the target vessel based on quantitative coronary angiography (QCA) and fluid dynamics algorithms. METHODS: Patients participating in the RESTORE ISR China randomized trial were enrolled and classified into the recurrent restenosis group and the non-recurrent restenosis group. The binary classifications followed the QCA standards of ISR. Clinical and angiographic characteristics of the groups were analyzed, and the QFRs before and after lesion preparation and after final DCB angioplasty were measured and compared. RESULTS: A total of 208 patients who underwent follow-up angiography were enrolled in the study, with 226 lesions measured in total. QFR value after DCB angioplasty (odds ratio [OR] 0.88; 95% confidence interval [CI] 0.83-0.93; p < .0001 for 1 mm increase), lesion length (OR: 1.08; 95% CI: 1.01-1.15; p = .017), and vessel caliber lumen diameter (OR: 0.35; 95% CI 0.13-0.89; p = .027) were independently associated with recurrent restenosis after DCB angioplasty. The optimal QFR cut-off value was determined to be 0.90 with a sensitivity of 0.94, specificity of 0.56, and accuracy of 0.79 in predicting recurrent restenosis. CONCLUSIONS: The QFR value after DCB angioplasty is a promising predictor of DES ISR.

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Two-dimensional (2D) hexagonal boron nitride (h-BN) is highly appreciated for its excellent insulating performance and absence of dangling bonds, which could be employed to maintain the intrinsic properties of 2D materials. However, controllable synthesis of large scale multilayer h-BN is still very challenging. Here, we demonstrate chemical vapor deposition (CVD) growth of multilayer h-BN by using iron boride (Fe2B) alloy and nitrogen (N2) as precursors. Different from the self-limited growth mechanism of monolayer h-BN on catalytic metal surfaces, with sufficient B source in the bulk, Fe2B alloy promotes the controllable isothermal segregation of multilayer h-BN by reacting with active N atoms on the surface of the substrate. Microscopic and spectroscopic characterizations prove the high uniformity and crystalline quality of h-BN with a highly orientated layered lattice structure. The achievement of large scale multilayer h-BN in this work would facilitate its applications in 2D electronics and optoelectronics in the future.

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BACKGROUND: Subclinical hypothyroidism (SCH) has recently been acknowledged as an unconventional risk factor for coronary artery disease (CAD) and characterized by poor prognosis, which may be due to atherosclerotic plaque characteristics. We conducted this study to observe coronary plaque characteristics in coronary artery disease patients with concomitant SCH. METHODS: Patients with coronary artery disease were enrolled in the study and divided into an SCH group (patients, n = 26; plaques, n = 35) and a non-SCH group (patients, n = 52; plaques, n = 66). They were divided 1: 2 according to propensity-matched analysis including age, diabetes mellitus, gender, CAD severity and culprit vessel. Optical coherence tomography (OCT) imaging was performed on all patients, and images were analyzed by two independent investigators. Lipid-rich plaques (LRP), the precursor of vulnerable plaques, were defined as having more than one quadrant occupied with lipid pool. Maximum lipid arcs were simultaneously recorded. Fibrotic plaques and calcific plaques were also identified. The presence of coronary dissection, plaque erosion, thrombus, macrophage, calcific nodule, thin-cap fibroatheroma and micro channel were all noted. RESULTS: The ratio of LRP in SCH group was significantly higher than that in non-SCH group (54% vs. 30.3%, P = 0.037). That was the case as well for the maximum lipid arcs value (181.5° ± 61.6° vs. 142.1° ± 35.9°, P = 0.046). While thin-cap fibroatheroma (TCFA) was detected, no difference was identified between the two groups in either TCFA ratio (20% vs. 16.7%, P = 0.579) or fibrous cap thickness (57.5 ± 14.0 vs. 63.5 ± 10.7 µm, P = 0.319). Other OCT characteristics such as dissection, plaque erosion, thrombus, macrophage shadow and calcific nodule were also similar. CONCLUSION: Higher ratio of LRP with greater lipid arc in SCH patients may be related to the plaque instability and poor prognosis in CAD patients with SCH.

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Knowledge or rule-based approaches are needed for quality assessment and assurance in professional or crowdsourced geographic data. Nevertheless, many types of geographic knowledge are statistical in nature and are therefore difficult to derive rules that are meaningful for this purpose. The rules of continuity and symmetry considered in this paper can be thought of as two concrete forms of the first law of geography, which may be used to formulate quality measures at the individual level without referring to ground truth. It is not clear, however, how much the rules can be faithful. Hence, the main objective is to test if the rules are consistent with street network data over the world. Specifically, for the rule of continuity we identify natural streets that connect smoothly in a network, and measure the spatial order of information (e.g. names, highway level, speed, etc.) along the streets. The measure is based on spatial auto-correlation indicators adapted for one dimension. For the rule of symmetry, we device an algorithm that recognize parallel road pairs (e.g. dual carriageways), and examine to what extent attributes in the pairs are identical. The two rules are tested against 28 cities selected from OpenStreetMap data worldwide; two professional data sets are used to show more insights. We found that the rules are consistent with street networks from a wide range of cities of different characteristics, and also noted cases with varying degrees of agreement. As a side-effect, we discussed possible limitations of the autocorrelation indicators used, where cautions are needed when interpreting the results. In addition, we present techniques that performed the tests automatically, which can be applied to new data to further verify (or falsify) our findings, or extended as quality assurance tools to detect data items that do not satisfy the rules and to suggest possible corrections according to the rules.

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Phase change memory (PCM) is a promising nonvolatile memory to reform current commercial computing system. Inhibiting face-centered cubic (f-) to hexagonal (h-) phase transition of Ge2Sb2Te5 (GST) thin film is essential for realizing high-density, high-speed, and low-power PCM. Although the atomic configurations of f- and h-lattices of GST alloy and the transition mechanisms have been extensively studied, the real transition process should be more complex than previous explanations, e.g. vacancy-ordering model for f-to-h transition. In this study, dynamic crystallization procedure of GST thin film was directly characterized by in situ heating transmission electron microscopy. We reveal that the equilibrium to h-phase is more like an abnormal grain growth process driven by surface energy anisotropy. More specifically, [0001]-oriented h-grains with the lowest surface energy grow much faster by consuming surrounding small grains, no matter what the crystallographic reconfigurations would be on the frontier grain-growth boundaries. We argue the widely accepted vacancy-ordering mechanism may not be indispensable for the large-scale f-to-h grain growth procedure. The real-time observations in this work contribute to a more comprehensive understanding of the crystallization behavior of GST thin film and can be essential for guiding its optimization to achieve high-performance PCM applications.

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BACKGROUND: Proteomics and bioinformatics may help us better understand the biological adaptations occurring during bovine mastitis. This systems approach also could help identify biomarkers for monitoring clinical and subclinical mastitis. The aim of the present study was to use isobaric tags for relative and absolute quantification (iTRAQ) to screen potential proteins associated with mastitis at late infectious stage. RESULTS: Healthy and mastitic cows' mammary gland tissues were analyzed using iTRAQ combined with two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS). Bioinformatics analyses of differentially expressed proteins were performed by means of Gene Ontology, metabolic pathways, transcriptional regulation networks using Blast2GO software, the Dynamic Impact Approach and Ingenuity Pathway Analysis. At a false discovery rate of 5%, a total of 768 proteins were identified from 6,499 peptides, which were matched with 15,879 spectra. Compared with healthy mammary gland tissue, 36 proteins were significantly up-regulated (>1.5-fold) while 19 were significantly down-regulated (<0.67-fold) in response to mastitis due to natural infections with Staphylococci aureus. Up-regulation of collagen, type I, alpha 1 (COL1A1) and inter-alpha (Globulin) inhibitor H4 (ITIH4) in the mastitis-infected tissue was confirmed by Western blotting and Immunohistochemistry. CONCLUSION: This paper is the first to show the protein expression in the late response to a mastitic pathogen, thus, revealing mechanisms associated with host tissue damage. The bioinformatics analyses highlighted the effects of mastitis on proteins such as collagen, fibrinogen, fibronectin, casein alpha and heparan sulfate proteoglycan 2. Our findings provide additional clues for further studies of candidate genes for mastitis susceptibility. The up-regulated expression of COL1A1 and ITIH4 in the mastitic mammary gland may be associated with tissue damage and repair during late stages of infection.

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