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Summary: This paper focuses on the steady‐state power distribution region of the modular multilevel converter (MMC) and the matching among its multiple constraints. First, an equivalent model of the steady‐state MMC is established, and its basic power distribution region is solved based on analysis. Second, the influence of the AC current constraint, the AC outlet voltage constraint, the modulation index constraint, the DC current constraint, and the DC voltage constraint on the power distribution region are studied through the phasor analysis method. The power distribution region under the multiple constraints is obtained, and the parameters matching principle among these constraints are studied. Finally, in PSCAD/EMTDC, the simulation results validate the correctness of the obtained power distribution region and the effectiveness of the parameters matching principle among the multiple constraints. [ABSTRACT FROM AUTHOR]

We report for the first time a stable and easily recoverable catalytic system that achieves an entirely mutual transformation of azobenzene and hydrazobenzene under very mild conditions. [Display omitted] • A stable catalytic system achieves hydrogenation/dehydrogenation cycles. • Hydrogenation/dehydrogenation reactions proceed under very mild conditions. • Dehydrogenation reaction proceeds with hydrogen as the by-product. Azobenzene and hydrazobenzene compounds are essential intermediates for synthesizing pharmaceuticals and dyes. Meanwhile, the hydrazobenzene/azobenzene couple is a potential hydrogen storage system when both the dehydrogenation of hydrazobenzene and the hydrogenation of azobenzenes can be achieved under mild reaction conditions. In this work, we report an entirely mutual transformation of azobenzene and hydrazobenzene under very mild conditions using porous BN supported Cu nanoparticles (Cu/PBN) as the catalyst for the first time. Direct oxidative dehydrogenation reaction proceeded in the open air with the removal of molecular hydrogen as the by-product and a wide range of hydrazobenzenes readily undergoes dehydrogenation, resulting in an excellent yield of the corresponding azobenzene. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) exhibits a higher sensitivity to myocardial ischemia/reperfusion (I/R) injury and may compromise the effectiveness of cardioprotective interventions, including ischemic preconditioning. We previously found that liver ischemic preconditioning (RLIPC) could limit infarct size post I/R in non-diabetic rat hearts and further exerted anti-arrhythmic effects in diabetic or non-diabetic rats after myocardial I/R, however, little is known regarding the effect of RLIPC on infarct-sparing in diabetic hearts. In this study, we evaluated the protective effects of RLIPC on I/R injury in streptozotocin-induced type 1 diabetic rats. Type 1 diabetes mellitus was induced by one-time intraperitoneal injection of streptozotocin in Sprague–Dawley rats. Rats were exposed to 45 min of left anterior descend in (LAD) coronary artery occlusion, followed by 3 h of reperfusion. For liver ischemic preconditioning, four cycles of 5 min of liver I/R stimuli were performed before LAD occlusion. The cardioprotective effect of RLIPC was determined in diabetic rats. Compared to non-RLIPC treated DM rats, RLIPC treatment significantly reduced infarct size and cardiac tissue damage, inhibited apoptosis in diabetic hearts post I/R. RLIPC also improved cardiac functions including LVESP, LVEDP, dp/dtmax, and − dp/dtmax. In addition, RLIPC preserved cardiac morphology by reducing the pathological score post I/R in diabetic hearts. Finally, Westernblotting showed that RLIPC stimulated phosphorylation of ventricular GSK-3β and STAT-5, which are key components of RISK and SAFE signaling pathways. Our study showed that liver ischemic preconditioning retains strong cardioprotective properties in diabetic hearts against myocardial I/R injury via GSK-3β/STAT5 signaling pathway. [ABSTRACT FROM AUTHOR]

Background: In December 2019, an outbreak of COVID-19 epidemic occurred in Wuhan, China and infection spread rapidly around the world. To limit the rapid spread locally and nationwide, the Chinese government locked down Wuhan city on January 23 and began implementing nationwide intensive community screening on February 16. Method: To assess the effectiveness of city lockdown and intensive community screening, we built a modified SIR model by introducing an α value into the classic SIR model. The α value represents the proportion of infected individuals who are not effectively isolated from susceptible individuals at a given time point. Results: The accuracy of the modified SIR model was validated using data from Guangdong and Zhejiang provinces. The lockdown of Wuhan city substantially reduced the α value for the rest of China excluding Hubei province, while only slightly reducing the α value for the city itself. Intensive community screening rapidly reduced the α value for Wuhan. Conclusion: City lockdown was efficient in controlling the spread of the epidemic from Wuhan to the rest of the country. Nationwide intensive community screening was extremely effective in suppressing the spread locally within Wuhan city. These experiences should urgently be shared with other countries to help halt the progressing worldwide pandemic. [ABSTRACT FROM AUTHOR]

Motivation Reticulate evolutionary histories, such as those arising in the presence of hybridization, are best modeled as phylogenetic networks. Recently developed methods allow for statistical inference of phylogenetic networks while also accounting for other processes, such as incomplete lineage sorting. However, these methods can only handle a small number of loci from a handful of genomes. Results In this article, we introduce a novel two-step method for scalable inference of phylogenetic networks from the sequence alignments of multiple, unlinked loci. The method infers networks on subproblems and then merges them into a network on the full set of taxa. To reduce the number of trinets to infer, we formulate a Hitting Set version of the problem of finding a small number of subsets, and implement a simple heuristic to solve it. We studied their performance, in terms of both running time and accuracy, on simulated as well as on biological datasets. The two-step method accurately infers phylogenetic networks at a scale that is infeasible with existing methods. The results are a significant and promising step towards accurate, large-scale phylogenetic network inference. Availability and implementation We implemented the algorithms in the publicly available software package PhyloNet (https://bioinfocs.rice.edu/PhyloNet). Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Powdery mildew of wheat is one of the major foliar diseases, causing significant yield loss and flour quality change. In this study, grain protein and starch response to powdery mildew infection were investigated. Total protein, glutenin and gliadin exhibited a greater increase in grains from infected wheat, while the content of total starch and amylopectin was decreased. Comparative proteomic analysis demonstrated that the overabundant protein synthesis-related proteins might facilitate the accumulation of storage proteins in grains from infected plants. The significant increase in triticin, serpin and HMW-GS in grains from infected wheat might relate to the superior gluten quality. In addition, overabundant carbohydrate metabolism-related proteins in grains from infected wheat were conducive to the depletion of starch, whereas the decreased abundance of ADP glucose pyrophosphorylase might be related to the deficiency of starch synthesis. These results provide a deeper understanding on the change of wheat quality under powdery mildew infection. [ABSTRACT FROM AUTHOR]

In the present work, we described the synthesis, antiviral profiles and metabolic stability in human plasma of compound 6 , a potential carbonate prodrug of HIV-1 NNRTI drug candidate RDEA427. Compound 6 was found to inhibit the wild-type (WT) and K103N/Y181C double mutant HIV-1 strains at nano- and submicromolar concentrations, respectively. Moreover, it displayed potent HIV-1 reverse transcriptase inhibitory activity (IC 50  = 0.264 μM). Further stability test in human plasma showed that 6 could release its active form RDEA427 in a linearly time-independent manner, possibly acting as a potential prodrug. [ABSTRACT FROM AUTHOR]

Text recognition in natural scene images is a challenging task that has recently been garnering increased research attention. In this paper, we propose a method for recognizing text by utilizing the layout consistency of a text string. We estimate the layout (four lines of a text string) using initial character extraction and recognition result. On the basis of the layout consistency across a word, we perform character extraction and recognition again using four lines, which is more accurate than the first process. Our layout estimation method is different from previous methods in terms of exploiting character recognition results and its use of a class-conditional layout model. More accurate and robust estimation is achieved, and it can be used to refine character extraction and recognition. We call this two-way process-from extraction and recognition to layout, and from layout to extraction and recognition-'bidirectional' to discriminate it from previous feedback refinement approaches. Experimental results demonstrate that our bidirectional processes provide a boost to the performance of word recognition. [ABSTRACT FROM AUTHOR]

Noise level is an important parameter to many image processing applications. For example, the performance of an image denoising algorithm can be much degraded due to the poor noise level estimation. Most existing denoising algorithms simply assume the noise level is known that largely prevents them from practical use. Moreover, even with the given true noise level, these denoising algorithms still cannot achieve the best performance, especially for scenes with rich texture. In this paper, we propose a patch-based noise level estimation algorithm and suggest that the noise level parameter should be tuned according to the scene complexity. Our approach includes the process of selecting low-rank patches without high frequency components from a single noisy image. The selection is based on the gradients of the patches and their statistics. Then, the noise level is estimated from the selected patches using principal component analysis. Because the true noise level does not always provide the best performance for nonblind denoising algorithms, we further tune the noise level parameter for nonblind denoising. Experiments demonstrate that both the accuracy and stability are superior to the state of the art noise level estimation algorithm for various scenes and noise levels. [ABSTRACT FROM AUTHOR]

Objective Methods Results Conclusion To investigate the effect of retaining the vessels around the orbicularis oculi muscle on reducing local swelling after blepharoplasty.A total of 309 patients undergoing blepharoplasty (total incision) were observed and randomly assigned to three groups; (A) conventional operation; (B) preservation of deep vessels; (C) preservation of anterior vessels of orbicularis oculi muscle. The groups were compared based on intraoperative blood loss, operation time, swelling, satisfaction, and complications.Among the 309 patients, 39 were lost to follow‐up. c Additionally, A had the shortest operation time, followed by C with slightly longer duration. On the 7th day, 15th day, and 1 month after surgery, both B and C demonstrated significantly lower levels of swelling compared to A. Moreover, patient satisfaction was higher in B and C than in A.Retaining either superficial or deep veins of the orbicularis oculi muscle can effectively reduce short‐term postoperative swelling. However, when retaining the superficial central group of this muscle during surgery, it is crucial to strictly control the amount of surrounding tissue around vessels. [ABSTRACT FROM AUTHOR]

Thermal stability of metakaolin -based geopolymer blended with rice husk ash with replacement levels of 5–20% by weight of MK was investigated. The phase composition, thermal stability and microstructure of geopolymer before and after high-temperature exposure were explored by using X-ray diffraction(XRD), Thermogravimetric analysis (TGA), Fourier Transform Infrared Spectrometer (FTIR), BET specific surface area test (BET) and Scanning electron microscope (SEM). The optimum chemical activity of rice husk ash can be obtained when calcined at 600 °C for 4 h. The addition of rice husk ash increases the compressive strength of geopolymer by accelerating the alkali-activated reaction process. The compressive strength at 28 days of curing increases by 24% with 15 wt% rice husk ash. The porous rice husk ash accelerates the discharge of water vapor from geopolymer and protects geopolymer from cracking caused by air pressure. The high chemical activity of rice husk ash accelerates the high-temperature geopolymerization process and contributes to the healing of microcracks. Rice husk ash reduces the melting sintering temperature of geopolymer from 870 °C to 780 °C, improves the formation of compact ceramic protective layer and prevents the high temperature spalling of geopolymer. Unlabelled Image • Rice hull ash calcined at 600 °C for 4 h has excellent chemical reactivity. • The compressive strength at 28 days of curing increases by 24% with 15 wt% RHA. • Rice husk ash improves the thermal stability of geopolymer. • 15 wt% rice husk ash reduces the sintering temperature from 870 °C to 780 °C. [ABSTRACT FROM AUTHOR]

Arterial tone is regulated by multiple ligand-receptor interactions, and its dysregulation is involved in ischemic conditions such as acute coronary spasm or syndrome. Understanding the distribution of vasoactive receptors on different arteries may help guide the development of tissue-specific vasoactive treatments against arterial dysfunction. Tissues were harvested from coronary, mesenteric, pulmonary, renal and peripheral human artery (n = 6 samples of each) and examined using a human antibody array to determine the expression of 29 vasoactive receptors and 3 endothelin ligands. Across all types of arteries, outer diameter ranged from 2.24 ± 0.63 to 3.65 ± 0.40 mm, and AVPR1A was the most abundant receptor. The expression level of AVPR1A in pulmonary artery was similar to that in renal artery, 2.2 times that in mesenteric artery, 1.9 times that in peripheral artery, and 2.2 times that in coronary artery. Endothelin-1 was expressed at significantly higher levels in pulmonary artery than peripheral artery (8.8 times), mesenteric artery (5.3 times), renal artery (7.9 times), and coronary artery (2.4 times). Expression of ADRA2B was significantly higher in coronary artery than peripheral artery. Immunohistochemistry revealed abundant ADRA2B in coronary artery, especially vessels with diameters below 50 μm, but not in myocardium. ADRA2C, in contrast, was expressed in both myocardium and blood vessels. The high expression of ADRA2B in coronary artery but not myocardium highlights the need to further characterize its function. Our results help establish the distribution and relative levels of tone-related receptors in different types of arteries, which may guide artery-specific treatments. [ABSTRACT FROM AUTHOR]

• 28-day flexural strength of geopolymer increases by 25% with 0.30 wt% GO. • GO/rGO accelerates the dissolution of fly ash microspheres and promotes the growth of geopolymer chain. • Electron binding energy of O1s, Si2p and Al2p confirms the change in geopolymerization degree. • The interfacial bonding mode of GO/rGO-geopolymer and reaction mechanism are proposed. This work aims to examine the impact of graphene oxide (GO) and reduced graphene oxide (rGO) on mechanical properties and microstructure of fly ash (FA) based geopolymer. Different schemes were proposed to prepare GO/rGO-geopolymer composites. The chemical composition, microstructure and hydration degree of GO/rGO modified geopolymer were characterized by using FTIR, XRD, DTG, SEM, XPS and BET. The experimental results show that GO/rGO changes the microstructural composition and pore diameter distribution of geopolymer. The increased average electron binding energy of the tetrahedron of [AlSiO 4 − or [AlSi 3 O 8 − leads to the acceleration of geopolymerization process. The decreased average pore volume and porosity confirms that GO/rGO accelerates the dissolution and hydration process of FA microspheres. GO and rGO exhibit different efficiency in promoting the hydration degree of geopolymer, which may be due to different functional groups and dispersion efficiency. Meanwhile, the flexural strength changes with addition of GO/rGO, which increases by 25% for the use of 0.30 wt% GO and 10% for the use of 0.10 wt% rGO. In general, GO and rGO are promising to promote the hydration of FA and increase the mechanical strength of geopolymer. [ABSTRACT FROM AUTHOR]

Previous studies have demonstrated that epigallocatechin gallate (EGCG) had certain protective effects on myocardial and renal ischemia reperfusion (I/R) injury. We aimed to research the special effects and underling mechanisms of EGCG on skeletal muscle I/R injury. We established an experimental rat model of I/R skeletal muscle injury and treated with different doses of EGCG. Hematoxylin eosin staining, TUNEL assay, ELISA, qRT-PCR and Western blotting were used to evaluate the effects of EGCG. EGCG significantly improved skeletal muscle function of I/R injury rats. Moreover, EGCG had positive effects on decreasing apoptosis of skeletal muscle tissues, alleviating oxidative stress damage and suppressing the production of inflammatory cytokines. Further, EGCG had positive effects on activating Nrf2/HO-1 signaling pathway. EGCG might be a powerful candidate compound for alleviating I/R injury in rat skeletal muscle. [ABSTRACT FROM AUTHOR]

The effects of 10% metakaolin addition on compressive strength, water absorption, shrinkage and microstructure evolution of cement paste after elevated temperatures exposure from room temperature to 800 °C were evaluated. The experimental results show that compressive strength increases at 200 °C and 400 °C compared with that obtained at ambient temperature. Up to 800 °C, compressive strength decreases rapidly. The addition of 10% metakaolin leads to the enhancement of compressive strength regardless of exposure temperatures. After thermal exposure at 400 °C, compressive strength reaches the maximum value. Thermal exposure degrades pore structure. A polynomial equation was used to indicate the shrinkage of cement paste or metakaolin-blended cement paste with testing days. Mechanical properties, permeability resistance, and shrinkage in cement pastes are closely related to the microstructure development. 10% metakaolin addition presents better thermal resistance, lower shrinkage and denser microstructure compared with pure cement paste before and after thermal exposure. [ABSTRACT FROM AUTHOR]

Three novel polyoxometalate (POM) clusters of K10Na10[Dy3(H2O)6Ni(H2O)(W3O11)(B-α-SbW9O33)3]·(H2O)45 (1), (NH4)5K4Na8[Dy3(H2O)6SbV(H2O)(W3O11)(B-α-SbW9O33)3]·(H2O)50 (2), and (NH4)9Na[Ni2(H2O)6(WO2)2(B-β-SbW9O33)2]·(H2O)24 (3) were successfully obtained using the same precursor under different ionic strength conditions. Structural analysis showed that compounds 1–3 possess discrepant structural characteristics in 1 M KCl, 1 M NH4Cl, and saturated NH4Cl, respectively. Among them, 2 is the first reported lanthanide cluster including both Sb3+ and Sb5+ in POM derivatives. Furthermore, the analysis of ac magnetic data proved that 1 and 2 embodied dramatic field-induced slow magnetic relaxation, and the effective barrier of 2 was estimated as Ueff/KB = 21.10 K based on the Orbach process. It was found that the structure and magnetic properties of POM materials can be regulated using an effective and satisfactory ionic strength-controlled strategy. [ABSTRACT FROM AUTHOR]

Retrograde cerebral perfusion and retrograde inferior vena cava perfusion at a pressure of 25 mmHg can protect brain and visceral organs during hypothermic circulatory arrest. Total body retrograde perfusion has been proposed as an alternative during aortic arch surgery. We describe two patients who received total body retrograde perfusion during hemi-arch replacement. The procedure had to be terminated at 8 and 15 minutes due to severe fluid retention and decline in cerebral oxygen saturation. Delirium occurred in one patient after surgery. We concluded that total body retrograde perfusion may be associated with high risk of hypoperfusion and should not be recommended. [ABSTRACT FROM AUTHOR]

Crystallographic overlap studies and pharmacophoric analysis indicated that diarylpyrimidine (DAPY)-based HIV-1 NNRTIs showed a similar binding mode and pharmacophoric features as indolylarylsulfones (IASs), another class of potent NNRTIs. Thus, a novel series of DAPY-IAS hybrid derivatives were identified as newer NNRTIs using structure-based molecular hybridization. Some target compounds exhibited moderate activities against HIV-1 IIIB strain, among which the two most potent inhibitors possessed EC 50 values of 1.48 μM and 1.61 μM, respectively. They were much potent than the reference drug ddI (EC 50 = 76.0 μM) and comparable to 3TC (EC 50 = 2.54 μM). Compound 7a also exhibited the favorable selectivity index (SI = 80). Preliminary structure-activity relationships (SARs), structure-cytotoxicity relationships, molecular modeling studies, and in silico calculation of physicochemical properties of these new inhibitors were also discussed. [ABSTRACT FROM AUTHOR]

Proteome characteristics of wheat leaves with the powdery mildew pathogen Blumeria graminis f. sp. tritici ( Bgt ) infection were investigated by two-dimensional electrophoresis and tandem MALDI-TOF/TOF-MS. We identified 46 unique proteins which were differentially expressed at 24, 48, and 72 h post-inoculation. The functional classification of these proteins showed that most of them were involved in photosynthesis, carbohydrate and nitrogen metabolism, defense responses, and signal transduction. Upregulated proteins included primary metabolism pathways and defense responses, while proteins related to photosynthesis and signal transduction were mostly downregulated. As expected, more antioxidative proteins were activated at the later infection stage than the earlier stage, suggesting that the antioxidative system of host plays a role in maintaining the compatible interaction between wheat and powdery mildew. A high accumulation of 6-phosphogluconate dehydrogenase and isocitrate dehydrogenase in infected leaves indicated the regulation of the TCA cycle and pentose phosphate pathway in parallel to the activation of host defenses. The downregulation of MAPK5 could be facilitated for the compatible interaction of wheat plants and Bgt . qRT-PCR analysis supported the data of protein expression profiles. Our results reveal the relevance of primary plant metabolism and defense responses during compatible interaction, and provide new insights into the biology of susceptible wheat in response to Bgt infection. [ABSTRACT FROM AUTHOR]

A series of amphiphilic rodlike α-cyanostilbene mesogens bearing an α-cyanostilbene core, with one/three lipophilic and flexible alkyl chains at one end and a polar oligooxyethylene (EO) at the opposite end, have been synthesized and investigated by polarized optical microscopy (POM), differential scanning calorimetry (DSC), X-ray scattering, scanning electron microscope (SEM), UV-vis spectroscopy and photoluminescence as well as CV measurements. These compounds can self-assemble into photoresponsive liquid crystalline phases and possess AIEE characteristics, mechanofluorochromic properties and Fe3+ recognition properties. The conductivity of the lithium cation complex was also measured to be 2.6 × 10−7 S m−1. Such compounds can be considered as a kind of multifunctional materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Diketopyrrolopyrrole (DPP) polycatenars with different links and side groups have been synthesized. • They can self-assemble into bicontinuous cubic phase (Cub v / Ia 3 ¯ d) and hexagonal columnar phase (Col hex). • They can act as gelators to form gels with different nanostructures. Novel diketopyrrolopyrrole (DPP) based polycatenars characterized with a long π-conjugated rigid calamitic core, different side groups (t -Boc, H or PEO) at the lactam N atoms of the central DPP core and terminal hydrophobic paraffinic chains were prepared via Sonogashira coupling reaction as key steps. The influence of different side groups, different links and the length of terminal alkyl chains on the properties of these DPP derivatives was discussed. Such DPP polycaterners can self-assemble into bicontinuous cubic phase (Cub v / Ia 3 ¯ d) and hexagonal columnar phase (Col hex) in their pure states, as well as organogels in solution. UV and PL spectra investigation reveals that these compounds can display broad and strong absorption in the region of 275–650 nm and can emit in the NIR region (650–850 nm) with low energy gap (1.94 ev), meanwhile ICT effects have been detected between such DPP polycaternars and C 70 , indicating the potential application of these compounds in solar cell. [ABSTRACT FROM AUTHOR]

Geopolymer is considered as a new generation of green building materials. However, metakaolin (MK) based geopolymers are prone to burst and lose mechanical strength after high temperature exposures. The high temperature gradient between the inner parts and outer surfaces of geopolymer is the main factor affecting its properties. In this work, the introduction of graphene oxide (GO) provides feasibility for improving the thermal stability of geopolymer. The optimal dispersion conditions of GO were determined and the prepared GO modified geopolymer was exposed to high temperature. The high temperature properties of geopolymer were described by measuring its surface morphology, compressive strength and linear shrinkage. The microstructure and phase transition of GO-MK geopolymer were explored by XRD, SEM, FT-IR and TG tests, and finally, the strengthening mechanism of GO was discussed. The results show that methanol is beneficial for stable dispersion of GO in alkaline environment. The addition of well-dispersed GO can accelerate the geopolymerization process and effectively prevent the development of cracks caused by thermal stress, thus improving the thermal stability of geopolymer. After high temperature exposure, the residual strength of the GO modified geopolymer was significantly higher than that of the control sample. The compressive strength of the modified geopolymer could reach to 25 MPa at 600 °C, which is 25% higher than that of the unmodified sample. [ABSTRACT FROM AUTHOR]