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Jin Wu,1 Yiting Luo,1 Yan Shen,2 Yuyao Hu,2 Fangyuan Zhu,1 Jiaqian Wu,1 Yingchao Liu3 1The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, 310053, People’s Republic of China; 2Department of Gastroenterology, The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, 310005, People’s Republic of China; 3Academic Affairs Office, Zhejiang Chinese Medical University, Hangzhou, 310053, People’s Republic of ChinaCorrespondence: Yingchao Liu, Academic Affairs Office, Zhejiang Chinese Medical University, Hangzhou, 310053, People’s Republic of China, Email jcjsylyc@163.comBackground: Traditional Chinese medicine (TCM) has the advantage of multi-component and multi-target, which becomes a hot spot in the treatment of numerous diseases. Shaoyao decoction (SYD) is a TCM prescription, which is mainly used to treat damp-heat dysentery clinically, with small side effects and low cost. However, its mechanism remains elusive. The purpose of this study is to explore the mechanism of SYD in the treatment of mice with ulcerative colitis (UC) induced by dextran sulfate sodium (DSS) through metabolomics and network pharmacology, and verify through molecular docking and immunohistochemistry, so as to provide a scientific basis for the role of SYD in the treatment of UC.Materials and Methods: Firstly, DSS-induced UC models were established and then untargeted metabolomics analysis of feces, livers, serum and urine was performed to determine biomarkers and metabolic pathways closely related to the role of SYD. Besides, network pharmacology was applied to screen the active components and UC-related targets, which was verified by molecular docking. Finally, metabonomics and network pharmacology were combined to draw the metabolite-pathway-target network and verified by immunohistochemistry.Results: Metabolomics results showed that a total of 61 differential metabolites were discovered in SYD-treated UC with 3 main metabolic pathways containing glycerophospholipid metabolism, sphingolipid metabolism and biosynthesis of unsaturated fatty acids, as well as 8 core targets involving STAT3, IL1B, IL6, IL2, AKT1, IL4, ICAM1 and CCND1. Molecular docking demonstrated that the first five targets had strong affinity with quercetin, wogonin, kaempferol and baicalein. Combined with metabolomics and network pharmacology, sphingolipid signaling pathway, PI3K/AKT-mTOR signaling pathway and S1P3 pathway were identified as the main pathways.Conclusion: SYD can effectively ameliorate various symptoms and alleviate intestinal mucosal damage and metabolic disorder in DSS induced UC mice. Its effect is mainly related to sphingolipid metabolism, PI3K/AKT-mTOR signaling pathway and S1P3 pathway.Keywords: metabolomics, UPLC-Q-TOF-MS, network pharmacology, Shaoyao decoction, ulcerative colitis

Yiting Luo,1 Jin Wu,1 Yingchao Liu,2 Yan Shen,3 Fangyuan Zhu,1 Jiaqian Wu,1 Yuyao Hu3 1The Second Clinical Medical College, Zhejiang Chinese Medical University, Hangzhou, People’s Republic of China; 2Academic Affairs Office, Zhejiang Chinese Medical University, Hangzhou, People’s Republic of China; 3The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, People’s Republic of ChinaCorrespondence: Yuyao Hu, The Second Affiliated Hospital of Zhejiang Chinese Medical University, 318 Chaowang Road, Hangzhou, People’s Republic of China, Email 20094017@zcmu.edu.cnPurpose: Shaoyao decoction (SYD) is a traditional Chinese medicine used to treat ulcerative colitis (UC). The exact mechanism of action of SYD in UC treatment is still unclear. Here, we examined the therapeutic effects of SYD in mice with dextran sulfate sodium (DSS)-induced colitis and explored the underlying mechanism.Methods: The experimental group was divided into normal control, UC, and SYD treatment groups. The UC model of C57BL/6 mice was induced using 3% (w/v) DSS for 7 days. SYD was orally administered for 7 days. The proximal and distal colonic metabolic profiles were detected using quadrupole-time-of-flight mass spectrometry-based untargeted metabolomics.Results: SYD significantly increased weight, reduced disease activity index scores, and ameliorated colon length shortening and pathological damage in mice. In the distal colon, SYD increased the abundance of phosphatidic acid and lysophosphatidylethanolamine and decreased the abundance of lactosylceramide, erythrodiol 3-palmitate, and lysophosphatidylcholine. In the proximal colon, SYD increased the abundance of palmitic acid, cyclonormammein, monoacylglyceride, 13S-hydroxyoctadecadienoic acid, and ceanothine C and decreased the abundance of tetracosahexaenoic acid, phosphatidylserine, and diglyceride.Conclusion: Our findings revealed that SYD could alleviate UC by regulating metabolic dysfunction, which provides a reference for further studies on SYD.Keywords: Shaoyao decoction, ulcerative colitis, metabolomics, UPLC-Q-TOF-MS, DSS-induced colitis mouse model

Fluorescence microscopy has been widely used in the field of biological imaging, but the disturbance of background noise has always been an unavoidable phenomenon. To obtain a background free image, a virtual HiLo based on edge detection (V-HiLo-ED) method for background removing is proposed, which is different from the existing popular software algorithms that obtain the background-free image by subtracting the estimated background, but the background-free image is directly reconstructed by estimating the foreground. Compared with two other popular software-based methods, the wavelet-based background and noise subtraction algorithm (WBNS) and the rolling ball algorithm (RBA), the V-HiLo-ED owns a better quality on achieving background-free imaging. Compared with hardware-based method such as HiLo method, V-HiLo-ED exhibits almost the same performance but faster speed. In combination with light sheet microscopy, the V-HiLo-ED further improves the signal-to-noise ratio of images with thick light-sheet. These experiment results indicate that the V-HiLo-ED owns the potentiality in many other image applications such as endoscopy.

The ion-pumping NQR complex is an essential respiratory enzyme in the physiology of many pathogenic bacteria. This enzyme transfers electrons from NADH to ubiquinone through several cofactors, including riboflavin (vitamin B2). NQR is the only enzyme reported that is able to use riboflavin as a cofactor. Moreover, the riboflavin molecule is found as a stable neutral semiquinone radical. The otherwise highly reactive unpaired electron is stabilized via an unknown mechanism. Crystallographic data suggested that riboflavin might be found in a superficially located site in the interface of NQR subunits B and E. However, this location is highly problematic, as the site does not have the expected physiochemical properties. In this work, we have located the riboflavin-binding site in an amphipathic pocket in subunit B, previously proposed to be the entry site of sodium. Here, we show that this site contains absolutely conserved residues, including N200, N203, and D346. Mutations of these residues decrease enzymatic activity and specifically block the ability of NQR to bind riboflavin. Docking analysis and molecular dynamics simulations indicate that these residues participate directly in riboflavin binding, establishing hydrogen bonds that stabilize the cofactor in the site. We conclude that riboflavin is likely bound in the proposed pocket, which is consistent with enzymatic characterizations, thermodynamic studies, and distance between cofactors.

A Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterium, designated ZYF650T, was isolated from the hadal seawater (9600 m) of the Mariana Trench. Results of phylogenetic analysis based on 16S rRNA gene sequences indicated that ZYF650T formed a lineage within the family Alteromonadaceae that was distinct from the most closely related species Marinobacter mobilis and Marinobacter nitratireducens with 16S rRNA gene sequences similarities of 98.0 and 97.7 %, respectively. Strain ZYF650T showed average nucleotide identity values of 75.7 % with Marinobacter hydrocarbonoclasticus , 73.3 % with Marinobacter mobilis and 79.3 % with Marinobacter nitratireducens , and DNA–DNAhybridization values of 21.5, 21.3 and 22.0 % with M. hydrocarbonoclasticus , M. mobilis and M. nitratireducens , respectively, which were lower than the threshold for species delineation. Strain ZYF650T grew with 0–14 % (w/v) NaCl (optimum, 7–8 %) at a temperature range of 10–45 °C (optimum, 28 °C) and pH 6.0–9.5 (optimum, pH 7.0–8.0). The sole respiratory quinone was ubiquinone-9 (Q-9). The polar lipids in ZYF650T comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, three unidentified polar lipids, two unidentified aminolipids and two phospholipids. The predominant fatty acids (more than 10 % of total fatty acids) were C18 : 1 ω9c (21.9 %), C16 : 0 (21.7 %), C12 : 0 3-OH (14.0 %), C16 : 1 ω9c (13.2 %) and C12 : 0 (12.2 %). The DNA G+C content of strain ZYF650T was 55.6 %. On the basis of polyphasic taxonomic analysis, strain ZY650T is considered to represent a novel specie of the genus Marinobacter in the family Alteromonadaceae , for which the name Marinobacter salinexigens sp. nov. is proposed. The type strain is ZYF650T (=JCM 33013T=MCCC 1K03552T).

Atmospheric snow accretion along the insulators can eventually bridge adjacent shed spacing, which pose severe risks to the security of power networks. Aiming to investigate the influence of snow accumulation on the electrical performance of various types of insulators, the flashover tests of snow-accreted insulators were conducted. The effects of various factors on the electrical characteristics of insulators were analysed based on the experimental data. Results show that AC arc flashover gradient of the insulator covered with nonuniform snow accumulation is lower than that of the uniform snow-covered insulator. The former is as low as 22.5% lower than the latter. Moreover, the AC arc flashover gradient of the porcelain and glass insulators is 0.27–6.27% higher than that of the DC. For a silicone rubber insulator, this gap is greater than 20%. The flashover gradient of the glass insulator is the minimum at the snow thickness of 10 mm. The flashover process of snow-covered insulator is neither similar to that of the contaminated insulator nor different from that of the iced insulator but a combination of the two. The presented work helps to better understand the flashover mechanism of snow-covered insulators, and take efforts to mitigate its effects.

A Gram-stain-negative, strictly aerobic, rod-shaped bacterium, without flagellum and designated ZYF765T, was isolated from seawater sampled at a depth of 4000 m in the Mariana Trench. Strain ZYF765T grew with 1–15 % (w/v) NaCl (optimum, 4 %), at 16–37 °C (28 °C) and at pH 6.0–10.0 (pH 7.0–8.0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain ZYF765T formed a lineage within the family Hyphomonadaceae , and was distinct from the most closely related species Glycocaulis abyssi , Glycocaulis albus and Glycocaulis alkaliphilus with 16S rRNA gene sequences similarities ranging from 98.42 to 98.63 %. The major respiratory quinone was ubiquinone-10 (Q-10). The polar lipids comprised three unidentified glycolipids, one unidentified aminophospholipid, one unidentified phospholipid and one unidentified aminolipid. The predominant fatty acids (more than 10 % of total fatty acids) were C18 : 1ω7c (46.2 %) and C18 : 0 (14.1 %). The DNA G+C content was 67.7 mol%. On the basis of the results of polyphasic taxonomic analysis, strain ZYF765T is considered to represent a novel species within the genus Glycocaulis , for which the name Glycocaulis profundi sp. nov. is proposed. The type strain is ZYF765T (=JCM 33028T=MCCC 1K03554T).

The crystallization effect during the phase transition of icing water has a significant impact on the electrical performance of an ice-covered insulator. However, the spatial distribution of conductive ions in the ice layer remains poorly understood. In this study, the crystallization effect was confirmed through a condensation test of the potassium permanganate solution. The influence of freezing water conductivity, ice thickness and equivalent salt deposit density on the spatial distribution of conductive ions was determined by a triangular ice sample, wherein the effect on the flashover characteristics of ice-covered insulator was investigated. Results show that MnO4- migrates to the unfrozen area during freezing, thus accumulating on the droplet top. The conductivity of melted water on the exterior surface of an ice sample is considerably higher than that of icing water. The former can reach a maximum of 5.7 times the latter when the freezing water conductivity method is adopted. This value is 9.7 for a polluted ice sample. A highly conductive water film forms on the insulator surface because of the crystallization effect in the melting period, thereby improving the leakage current and reducing the residual ice resistance, which results in the decrease of flashover voltage.

The research on snow-accreted insulators have been performed in an artificial climate chamber. However, the differences in the distribution, density and compactness of snow accretion under natural and artificial simulation environments cause differences in the flashover performance of snow-covered insulators. In the present work, a series of flashover tests were conducted on snow-coated glass and silicone rubber insulators in the climate chamber and at Xuefeng Mountain Natural Icing Test Base. The discrepancies in the electrical characteristics and flashover process of snow-covered insulators under two test environments were compared and analyzed. Results show that the arc flashover gradient of snow accreted insulator at high altitude site is higher than that in the laboratory because of the differences of the environmental parameters. Affected by the adiabatic effect and capillary action of snow layer, within the range of the study the flashover gradient of insulators covered with snow increases with the increasing in the snow thickness. The calculation of various forces applied on arcs during its propagation demonstrates that when the arc current is less than 0.2 A, the local arcs develop along the snow surface of the insulators under the action of an electrostatic force. As the current increases beyond 0.2 A, the thermal buoyancy is predominant, thereby causing arcs to levitate from the insulator surface.

Pregnancy-associated breast cancer (PABC) is diagnosed during pregnancy or within 1 year postpartum, but the unique aspects of its etiology and pathogenesis have not been fully elucidated. This study aimed to ascertain the molecular mechanisms of PABC to facilitate diagnosis and therapeutic development. The Limma package was used to characterize the differentially expressed genes in PABC as compared to non-pregnancy-associated breast cancer (NPABC) and normal breast tissue. A total of 871 dysregulated genes were identified in the PABC versus NPABC groups and 917 in the PABC versus normal groups, with notable differences in the expression of MAGE and CXCL family genes. The dysregulated genes between the PABC and normal groups were mainly associated with signal transduction and immune response, while Kyoto Encyclopedia of Genes and Genomes analysis revealed that the dysregulated genes were enriched in immune-related pathways, including the major histocompatibility complex (MHC) class II protein complex, the type I interferon signaling pathway, regulation of α-β T-cell proliferation, and the T-cell apoptotic process. Through protein-protein interaction network construction, CD44 and BRCA1 were identified as prominent hub genes with differential expression in PABC versus NPABC. Furthermore, a cluster with eleven hub genes was identified in PABC versus normal adjacent tissues, of which the expression of EGFR, IGF1, PTGS2, FGF1, CAV1, and PLCB1 were verified to be differentially expressed in an independent cohort of PABC patients. Notably, IGF1, PTGS2, and FGF1 were demonstrated to be significantly related to patient prognosis. Our study reveals a distinctive gene expression pattern in PABC and suggests that IGF1, PTGS2, and FGF1 might serve as biomarkers for diagnosis and prognosis of PABC.

Light sheet fluorescence microscopy (LSFM) utilizes a light sheet to optically section samples, giving it the advantages of high signal-to-noise ratio, low phototoxicity and rapid three-dimensional imaging, which is an ideal tool for long-time microscopic observation of living samples. However, due to the inherent characteristics of Gaussian light sheet, there is a contradiction between the field of view and depth resolution of LSFM. In life science research, high depth resolution is necessary to resolve fine structures of biological systems such as neurons. However, in order to maintain a large field of view, the thickness of Gaussian light sheet is limited. Here, we propose a depth resolution enhancement method for LSFM. The incorporation of light field imaging into LSFM allows the acquirement of light field information within the Gaussian light sheet. By using the light field back projection (LFBP) reconstruction algorithm and depth estimation algorithm, it is possible to obtain the depth information in a light sheet, so as to improve the depth resolution. We built a light field light sheet fluorescence microscope (LFLSFM), and demonstrated it by fluorescent microsphere experiments. The proposed method can achieve a depth resolution of 0.5um when the thickness of the light sheet is kept at 6um to ensure a large field of view. Therefore, the method has potentialities in visualizing neural network of tissues and organs such as mouse brain.

This study investigated the different addition levels of iron (Fe) in growing-finishing pigs and the effect of different Fe levels on growth performance, hematological status, intestinal barrier function, and intestinal digestion. A total of 1,200 barrows and gilts ([Large White × Landrace] × Duroc) with average initial body weight (BW; 27.74 ± 0.28 kg) were housed in 40 pens of 30 pigs per pen (gilts and barrows in half), blocked by BW and gender, and fed five experimental diets (eight replicate pens per diet). The five experimental diets were control diet (basal diet with no FeSO4 supplementation), and the basal diet being supplemented with 150, 300, 450, or 600 mg/kg Fe as FeSO4 diets. The trial lasted for 100 d and was divided into the growing phase (27 to 60 kg of BW) for the first 50 d and the finishing phase (61 to 100 kg of BW) for the last 50 d. The basal diet was formulated with an Fe-free trace mineral premix and contained 203.36 mg/kg total dietary Fe in the growing phase and 216.71 mg/kg in the finishing phase based on ingredient contributions. And at the end of the experiment, eight pigs (four barrows and four gilts) were randomly selected from each treatment (selected one pig per pen) for digesta, blood, and intestinal samples collection. The results showed that the average daily feed intake (P = 0.025), average daily gain (P = 0.020), and BW (P = 0.019) increased linearly in the finishing phase of pigs fed with the diets containing Fe. On the other hand, supplementation with different Fe levels in the diet significantly increased serum iron and transferrin saturation concentrations (P < 0.05), goblet cell numbers of duodenal villous (P < 0.001), and MUC4 mRNA expression (P < 0.05). The apparent ileal digestibility (AID) of amino acids (AA) for pigs in the 450 and 600 mg/kg Fe groups was greater (P < 0.05) than for pigs in the control group. In conclusion, dietary supplementation with 450 to 600 mg/kg Fe improved the growth performance of pigs by changing hematological status and by enhancing intestinal goblet cell differentiation and AID of AA.

A new type of the insulator named integrated lightning protection insulator incorporates insulation function of the insulator and lightning protection function of the arrester. Due to the particularity of the structure, the electric field and flow field characteristics of the lightning protection insulator with DC are bound to be different from common composite insulator in a snowfall environment. Therefore, based on the field charging theory, the influences of electric field force, gravity and air drag force on wet snow particles were taken into account. The movement characteristics of particles near the surface of two types of the insulators were analyzed and compared through multi-physics coupling simulation and the effect of DC electric field on the trajectories of wet snow particles around the two was revealed. The results show that wet snow particles are more likely to collide with the insulator surface under DC electric field, especially for locations with a high electric field strength. As the wind speed and particle diameter increase, the influence of the electric field is weakened, and the movement of particles tends to the upper and lower surfaces of the insulator. Numerical simulation reveled that the change in the movement direction and speed of wet snow particles caused by DC electric field is the primary cause of the intensification of snow accretion on the insulator.

Phytopathogens deploy glycoside hydrolases (GHs) to disintegrate plant cell walls for nutrition and invasion. However, the pathogenic mechanisms of the majority of GHs in virulence remain unknown, especially in oomycetes. In this study, a Phytophthora sojae gene encodes a GH7 family cellobiohydrolase, named PsGH7a, was identified. PsGH7a was highly induced during the cyst germination and infection stages. PsGH7a is conserved in oomycetes, and shares a high amino acid sequence identity (>85%) within Phytophthora genus. The recombinant PsGH7a catalyzes the hydrolysis of β-1,4-glucan and avicel, which represent the major components of cellulose in plant cell wall. The mutation of catalytic residue Glu236 to alanine resulted in a lower catalytic activity. In addition, the PsGH7a promotes Phytophthora invasion, while the mutant can not. Notably, PsGH7a protein triggers hypersensitive cell death in diverse plants. PsGH7a knockout mutants were generated via CRISPR/Cas9 system, to investigate its biological function. Compared to wild-type strain P6497, the mutants showed reduced virulence on susceptible soybean, indicates PsGH7a is indispensable to P. sojae virulence.

Phytopathogens deploy glycoside hydrolases (GHs) to disintegrate plant cell walls for nutrition and invasion. However, the pathogenic mechanisms of the majority of GHs in virulence remain unknown, especially in oomycetes. In this study, a Phytophthora sojae gene encodes a GH7 family cellobiohydrolase, named PsGH7a, was identified. PsGH7a was highly induced during the cyst germination and infection stages. PsGH7a is conserved in oomycetes, and shares a high amino acid sequence identity (>85%) within Phytophthora genus. The recombinant PsGH7a catalyzes the hydrolysis of β-1,4-glucan and avicel, which represent the major components of cellulose in plant cell wall. The mutation of catalytic residue Glu236 to alanine resulted in a lower catalytic activity. In addition, the PsGH7a promotes Phytophthora invasion, while the mutant can not. Notably, PsGH7a protein triggers hypersensitive cell death in diverse plants. PsGH7a knockout mutants were generated via CRISPR/Cas9 system, to investigate its biological function. Compared to wild-type strain P6497, the mutants showed reduced virulence on susceptible soybean, indicates PsGH7a is indispensable to P. sojae virulence.

Ice accretion on the insulators can reduces the creepage distance to a certain extent as low as the dry arc distance, which may cause flashover trip and subsequent blackout. Extensive research on insulator icing has been carried out in a controlled-climate room. Due to great differences in environmental parameters between laboratory simulation and field tests, icing characteristics and discharge development of ice-covered insulator obtained in the laboratory cannot veritably reflect natural icing law and arc propagation process. Consequently, in the present study the glaze-icing on energized insulators was investigated on site, and the mechanism of icicle growth on the insulator energized with different voltage levels was revealed. Meanwhile, AC flashover performances and arc discharge development of ice-coated insulators for the two test conditions were compared and discussed. Results show that for a weak electric field, icicle firstly grows vertically, and then bends to the axis of the insulator when its length reaches to a certain level. Nevertheless, icicle develops towards the axis at the beginning under a high electric field. AC flashover voltage of ice-accreted insulators increases exponentially with an increasing applied voltage, while the relation of flashover voltage and ice weight fits well with a negative power function. Icing flashover voltage of the insulators obtained in natural environment is 14%～21% higher than that in the chamber. Compared with the flashover in the laboratory, during the discharge of the insulators naturally covered with ice, arc extinction-reignition and floating phenomena are more significant, and the ice-melting is more severe.

The indigenous and foreign scholars have conducted considerable research on the electrical characteristics of ice-covered insulators, but there is a lack of research on the growth process of ice accretion on insulators. On the basis of the heat and mass balance during icing, a complete wet-growth icing model, including the ice accretion on the insulator surface and the growth of icicles is established. In this model, the loss of water film on the insulator surface and the water supply for icicles are taken into account, and rebuild the icicle growing equations according to the water mass balance. The effect of flow-field change due to the growth of icicles is considered and analysed. The simulation results indicate that the growth of icicles and ice thickness are affected by climate parameters and the flow-field change. Low temperature and high wind speed can increase the growing rate of icicles and the ice thickness and decrease the time of icicle bridging. The change of flow field leads to changes in water mass balance and slows the progress of icing on the insulator surface. Through a series of icing tests on insulator FXBW-110/100, it is found that the experimental results are in good agreement with those obtained by the numerical simulation method.

Under natural environment, the washing effect of rainfall has great influence on the cleaning of outdoor insulators. To study the law of natural contamination on the insulator surface in the rainy weather. The natural contamination experimental study has been carried out for four 500 kV transmission lines in hundreds of sites and stations in Hunan Province for five years. The equivalent salt deposit density (ESDD) and non-soluble deposit density (NSDD) were measured monthly, and the meteorological data were statistically analysed. The results show that the residual ESDD and NSDD on the surface of insulators were affected by the rainfall intensity, duration and flushing angle. Meanwhile, based on the measured data of ESDD and NSDD, a cleaning model of insulators was established. The effects of splash on the bottom surface of insulators were studied by using the raindrop kinetic energy and Gaussian probability statistical distribution.

The electrical characteristics of ice-covered insulators in coexisting conditions of high altitude, icing and pollution are a basis for external insulation selection of transmission lines in icing regions. Ice accretion on insulators has been studied for decades, while few studies focus on the flashover performance of ice-covered insulators polluted by two types of contamination, that is the solid layer method and icing water conductivity method, simultaneously. On the basis of the investigations on DC flashover performance of ice-covered insulators in the artificial climate chamber, the influence of different parameters, such as insulator string length, icing water conductivity, salt deposit density as well as atmospheric pressure on DC icing flashover voltage of insulator strings is studied. According to the experimental results, the relationships between the flashover voltage and each of such factors are determined and analysed. Moreover, the correction formula for DC flashover voltage of ice-covered insulators in complex ambient conditions is proposed.

Icing experiments on three units of XP4-160 insulator string are conducted to reveal the influence of the crystallisation effect of conductive ions during phase transition on melting water conductivity and ice flashover voltage, and to analyse the motion of conductive ions and its spatial distribution. The influence of different parameters, such as freezing water conductivity, electric field and pollution, on crystallisation effect is examined and analysed. Results of the tests indicate that the melting water conductivity of the ice layer and icicles is considerably greater than that of freezing water, particularly for a polluted insulator, because of the crystallisation effect. The electric field has a significant influence on the crystallisation effect, that is, the melting water conductivity under a non-energised condition is higher than that under an energised condition. Finally, through 35 kV insulator flashover tests, the reason for the propagation of partial arcs over icicles is determined, and the flashover process is illustrated. The crystallisation effect during phase transition changes the ion distribution in a solid ice layer, thereby increasing water film conductivity, and is also a critical reason for the decline of ice flashover voltage.

Pseudomonas aeruginosa is a Gram-negative γ-proteobacterium that forms part of the normal human microbiota and it is also an opportunistic pathogen, responsible for 30% of all nosocomial urinary tract infections. P. aeruginosa carries a highly branched respiratory chain that allows the colonization of many environments, such as the urinary tract, catheters and other medical devices. P. aeruginosa respiratory chain contains three different NADH dehydrogenases (complex I, NQR and NDH-2), whose physiologic roles have not been elucidated, and up to five terminal oxidases: three cytochrome c oxidases (COx), a cytochrome bo3 oxidase (CYO) and a cyanide-insensitive cytochrome bd-like oxidase (CIO). In this work, we studied the composition of the respiratory chain of P. aeruginosa cells cultured in Luria Broth (LB) and modified artificial urine media (mAUM), to understand the metabolic adaptations of this microorganism to the growth in urine. Our results show that the COx oxidases play major roles in mAUM, while P. aeruginosa relies on CYO when growing in LB medium. Moreover, our data demonstrate that the proton-pumping NQR complex is the main NADH dehydrogenase in both LB and mAUM. This enzyme is resistant to HQNO, an inhibitory molecule produced by P. aeruginosa, and may provide an advantage against the natural antibacterial agents produced by this organism. This work offers a clear picture of the composition of this pathogen’s aerobic respiratory chain and the main roles that NQR and terminal oxidases play in urine, which is essential to understand its physiology and could be used to develop new antibiotics against this notorious multidrug-resistant microorganism.

Snow accumulates on the surface of insulator string, causing a decrease in its electrical performance, seriously threatening the reliable operation of the power grid. Most previous studies have focused on iced insulators, however, there is a lack of research on snow-covered insulators. In this paper, to reveal the influencing mechanism that snow has on the electrical characteristics of insulator string, based on an artificial snowing test in a chamber, the effects of equivalent salt deposit density, applied voltage type, and snow thickness on the flashover performance of snow-covered insulators are analyzed, and the flashover process is investigated. The results show that the relationship between the arc flashover gradient and the equivalent salt deposit density is a power function with a negative exponent, which is similar to that of polluted and ice-covered insulator strings. For the insulator strings with the same snow accretion, the direct current (DC) arc flashover gradient is lower than the alternating current (AC) arc flashover gradient. The relationship between arc flashover gradient and snow thickness is also a power function. The formation of a dry band during the flashover of snow-covered insulator string is similar to the flashover of the polluted insulator, and the arc propagation along the surface of the snow-covered insulator is similar to the flashover of the iced insulator.

The advent of knowledge economy and recent boom in knowledge management practices has created the conditions for a wide range of publishing enterprises to take full advantage of knowledge resources to enhance their own competing abilities and decision response efficiency in the E-commerce. The infusion between E- commerce and knowledge management in publishing enterprises can result in the formation of Knowledge Commerce. But how to realize its practices depends on the construction of one kind of system platform integrating E-commerce with knowledge management by means of some radical technologies, say, web mining and ontology-based knowledge portal technologies can play an important role in the detection and refinement of clients' information, staffs' knowledge and integration of knowledge flows in E- commerce practices.