Hemolytic Escherichia coli are important pathogens in neonatal and weaned pigs. In this study, we analyzed 95 hemolytic E. coli isolated from intestinal contents or fecal samples of diarrheic piglets ...in 15 states of the United States between November 2013 and December 2014. Phenotypic antimicrobial susceptibility was determined through Sensititre BOFO6F plates for all the strains. They were all resistant to clindamycin, penicillin, tiamulin, tilmicosin, and highly resistant to oxytetracycline (91.6%), chlortetracycline (78.9%), ampicillin (75.8%), and sulfadimethoxine (68.4%). 86.2% of them were multidrug resistant. Whole genome sequencing (WGS) showed that 55 strains were enterotoxigenic E. coli (ETEC) and 40 strains were non-ETEC, and the strains belonged to 22 known and 2 novel sequence types (STs). ST100 and ST10 were the main and predominant STs in ETEC strains, whereas the non-ETEC strains were diverse with ST23 and ST761 as the main STs. Antibiotic resistance gene/mutation profiling of the genomes confirmed the results of antimicrobial susceptibility test. Notably, significant differences were found in the susceptibility to enrofloxacin between ETEC and non-ETEC (58.2% vs. 5.0%) and gentamicin (32.7% vs. 7.5%). ampH, ampC2, and ampC1 were the most common beta-lactamase genes in all E. coli strains, and extended-spectrum beta-lactamase (ESBL) genes were rare in these isolates. This study provides new insights into antibiotic resistance and genotypes of intestinal pathogenic E. coli associated with swine disease in the United States, and support the utility of WGS in accurate prediction of resistance to most antibiotics.
Although fluorinated graphene (FG) inherits the physical barrier characteristic from graphene, its limited dispersibility seriously impedes its application in corrosion resistance. Here, this study ...aims to present a facile strategy to effectively eliminate this undesired feature of FG. We developed a well-dispersed cerium oxide grafting fluorinated reduced graphene oxide (FrGO@CeO2) nanofiller to enhance the anti-corrosion properties of epoxy coating on Q235 mild steel surfaces. The in situ F-doping and hydrothermal techniques were employed to synthesize FrGO@CeO2 nanofillers and functionalize them with waterborne epoxy coating. Combining the electrochemical results and the corrosion morphologies, the resultant nanofillers were found to significantly reinforce the protection properties of epoxy coatings due to the physical barrier effect derived from FrGO. In addition to impermeability, FrGO presented the insulating nature and endowed composite coatings to combat galvanic corrosion. Local electrochemical impedance spectroscopy (LEIS) indicated that cerium oxide adsorbed on mild steel surface could form a passive layer and thus further resisted the metal corrosion process. The related corrosion protection mechanism of FrGO@CeO2/EP coating was proposed in detail, which could provide broader platforms for designing new corrosion protection materials.
Display omitted
To investigate the expression of endothelial nitric oxide synthase (eNOS) and nitric oxide (NO) in the aorta of subclinical hypothyroidism (SCH) rat model. The mechanisms underlying thyrotropin (TSH) ...affecting eNOS and PGRN expression in human umbilical vein endothelial cells (HUVECs) cultured
were investigated. In the current study, SCH rat models were established by the administration of L-T
injection after thyroidectomy in Wistar rats, as opposed to that in the normal and clinical hypothyroidism (CH) groups. The concentrations of NO (pmol/μL) in the SCH and CH groups were significantly lower than that in the normal group (40.8 ± 7.6 and 32.9 ± 10.8 vs. 51.2 ± 12.1,
< 0.05). However, the expression level of eNOS is increased significantly (
< 0.05) in both SCH and CH groups; a similar result was observed for the PGRN protein. In cultured HUVECs, TSH can also up-regulate the expression of eNOS; however, it is accompanied by a reduced concentration of NO and increased level of superoxide anion, thereby indicating uncoupled eNOS. As eNOS is increased, we found that Akt in HUVECs were upregulated by TSH, as well as PGRN expression. While inhibiting the expression of PGRN in HUVECs using siRNA, the expression of eNOS, as well as Akt were also inhibited. In conclusion, SCH can induce vascular endothelial dysfunction in rats, and PGRN participated in the process of TSH-induced expression of Akt/eNOS in the endothelium.
Numerous epidemiological studies have shown that subclinical hypothyroidism (SCH) can impair endothelial function and cause dyslipidemia. Studies have evaluated the effects of thyroid stimulating ...hormone (TSH) on endothelial cells, but the mechanism underlying the proatherosclerotic effect of increased TSH levels remains unclear. In the present study, SCH rat models were established in thyroidectomized Wistar rats that were given ʟ-T4 daily. The results showed that in vivo, the expression of osteopontin (OPN) vascular cell adhesion molecule (VCAM-1), and levels of integrin αvβ3 in the aortic tissue in SCH and Hypothyroidism (CH) groups was higher than in the control group. However, the effect in the SCH group was higher than in the CH group. In vitro, results showed that different concentration and time gradients of TSH stimulation could increase the expression of OPN, VCAM-1, and integrin αvβ3, and this was accompanied by extracellular signal regulated kinase 1/2 (Erk1/2) and Akt activation in human umbilical vein endothelial cells (HUVECs). TSH induced elevation of these proatherosclerotic factors was partially suppressed by a specific Akt inhibitor but not by a specific Erk inhibitor. Findings suggested that the endothelial dysfunction caused by SCH was related to increased proatherosclerotic factors induced by TSH via Akt activation.
In this work, a polyethyleneimine-grafted graphene oxide (PEI-GO) hybrid material was prepared as an effective filler to improve the anticorrosion performance of waterborne epoxy coating. The ...successful covalent reaction between PEI and GO was confirmed by FTIR, Raman, XPS, XRD and TGA measurement. The epoxy coating filled with modified and unmodified graphene oxide was characterized by SEM and Raman spectroscopy. The results showed that PEI-GO was uniformly dispersed in the epoxy matrix. It was found that the PEI-GO hybrid materials displayed considerable superiorities in improving corrosion resistance of epoxy coating by EIS and SVET. Besides, the optimal content (0.25 wt%) of PEI-GO was obtained through experimental results. Moreover, the desirable anticorrosive property of PEI-GO/EP composite coating is proposed to be mainly attributed to the role of PEI, which fully stimulated the barrier properties of graphene oxide by improving its dispersion in the epoxy coating and also enhanced the crosslink density of epoxy resin by increasing the surface activity of the graphene oxide to the epoxy groups.
Display omitted
•Polyethylenimine (PEI) was grafted on graphene oxide (GO) surface.•The PEI-GO hybrid improved the compatibility between GO and epoxy resin (EP).•The PEI-GO/EP composite coating had longer service life and better anti-corrosion property.•The presence of PEI-GO hybrid increased the density of epoxy coating and suppressed the corrosion of metal substrate.
The aims of this study performed in 2007 were to verify the selection criteria proposed by the National Academy of Clinical Biochemistry (NACB) guidelines, to investigate factors that influence ...thyrotropin (TSH) levels, and to determine serum TSH reference range in iodine sufficient areas of China. After excluding 291 subjects, a total of 5,348 inhabitants from three iodine sufficient areas of Liaoning province were asked to fulfill the questionnaire, and take TSH, thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb) measurements and a thyroid ultrasound examination. The distribution of TSH was right skewed in normal people. It has been customary to log transform the values to observe the Gaussian distribution. In the subjects 12-19 years of age, the TSH level was significantly higher than in the other age groups (p<0.001), while there were no significant difference in the TSH values of the other age groups. The TSH levels in females(1.68±1.90mIU/L) were significantly higher than in males (1.45±1.92mIU/L) (p<0.001). Therefore, the normal TSH range in males over age 20 was 0.43-4.74mIU/L, and in females the range was 0.48-5.39 mIU/L. A family history of thyroid disease, abnormal thyroid ultrasound, a thyroid antibody-positive status were the factors that influenced the TSH reference range. Non-thyroid disease did not impact the TSH reference range significantly. We recommend use of a TSH reference range 0.46-5.19mIU/L in iodine sufficient areas of China for males and females over 20 years old. We suggest using a normal thyroid ultrasound as a new criterion in addition to the NACB guidelines to determine the TSH reference range.
Display omitted
•GO with different aspect ratios were prepared and the uniform GO/epoxy composite coatings were fabricated.•Anti-corrosion performance of composite coatings containing GO sheets with ...different aspect ratio were investigated.•Anti-corrosion mechanism of different GO/epoxy composite coatings were studied.•The aspect ratio of GO sheets was a significant factor for enhancing corrosion resistance of GO/epoxy coatings.
Graphene oxide (GO) has a wide application prospect in the field of metal protection due to its good dispersion, chemical activity and physical barrier property. Herein, graphene oxide sheets with different aspect ratio were first prepared by simply controlling the procedure of chemical exfoliation and then used to fabricate GO/epoxy composite coatings. The morphology and structural features of as-prepared GO sheets were characterized by Raman spectroscopy, X-ray diffraction and atomic force microscopy. The dispersion and anticorrosive performances of GO with different aspect ratios incorporated in epoxy-based waterborne composite coatings were investigated by Raman spectroscopic mapping, electrochemical measurements and scanning vibrating electrode technique. The results demonstrated that the different types of GO showed homogeneous dispersion in epoxy resin and GO with higher aspect ratio exhibited larger corrosion protection potential. Furthermore, the anti-corrosion mechanisms for composite coatings enhanced via GO with different aspect ratio were tentatively proposed, which indicating that the GO sheets with higher aspect ratio provided a more tortuous permeation path for corroding medium and thus displayed better corrosion resistance.
Display omitted
Although substantial statements report the capability of graphene for corrosion prevention, its further application is limited by the non-comprehension of its structural variation in ...different coatings. Herein, graphene sheets with four structures were incorporated waterborne epoxy to fabricate different types of composite coatings (named EP-Ga, EP-Gb, EP-GO and EP-GS, respectively) as well as the pure waterborne epoxy coating was fabricated for comparison. The corrosion behaviors of as-fabricated coatings with and without graphene sheets were systematically characterized via potential, impedance testing and Tafel curves by immersing in 3.5 wt % NaCl solution. It was remarkable to point out that EP-Ga composite coating could possess a promising long-term corrosion protection capability. The corrosion protection mechanism of graphene-based composite coatings were verified as the barrier effect of impermeable graphene sheets that confirmed by the analysis of corrosion products. Moreover, the scanning vibrating electrode technique in-depth revealed the relationship between the graphene structures and corrosion performances of the composite coatings. With the occurrence of commercialized application of graphene-based coatings, these works displayed a suitable approach toward the long-term corrosion behavior, which was able to be extended to other two-dimensional materials for anti-corrosion coatings.
ABSTRACT
Extraintestinal pathogenic
Escherichia coli
(ExPEC) is responsible for severe bloodstream infections in humans and animals. However, the mechanisms underlying ExPEC’s serum resistance remain ...incompletely understood. Through the transposon-directed insertion-site sequencing approach, our previous study identified
nhaA
, the gene encoding a Na
+
/H
+
antiporter, as a crucial factor for infection
in vivo
. In this study, we investigated the role of NhaA in ExPEC virulence utilizing both
in vitro
models and systemic infection models involving avian and mammalian animals. Genetic mutagenesis analysis revealed that
nhaA
deletion resulted in filamentous bacterial morphology and rendered the bacteria more susceptible to sodium dodecyl sulfate, suggesting the role of
nhaA
in maintaining cell envelope integrity. The
nhaA
mutant also displayed heightened sensitivity to complement-mediated killing compared to the wild-type strain, attributed to augmented deposition of complement components (C3b and C9). Remarkably, NhaA played a more crucial role in virulence compared to several well-known factors, including Iss, Prc, NlpI, and OmpA. Our findings revealed that NhaA significantly enhanced virulence across diverse human ExPEC prototype strains within B2 phylogroups, suggesting widespread involvement in virulence. Given its pivotal role, NhaA could serve as a potential drug target for tackling ExPEC infections.
Summary
Lithium‐ion batteries (LIBs) are extensively applied in various portable electronic equipment because of their high energy density power. However, accidents related to LIBs frequently occur. ...This study focuses on failure results, characteristics, and phenomena. Lithium‐ion batteries under different states of charge (SOCs) (0%, 30%, 50%, 80%, 100%, and 120%) at high temperatures have been investigated with the thermal abuse test. During the experiments, several typical failure processes were captured. According to the phenomena, 2 failure modes (smoke and jet fire) and 3 stages (primary reaction, tempestuous reaction in the middle time period, and extinguishing reaction in the final stage) were observed. A substantial amount of gas was vented, and jet fire was detected in the middle period. Only gas vented when the SOC was lower than 50%, whereas vented gas and jet fire were detected simultaneously when the SOC exceeded 50%. The results indicated combustible behaviors and exothermic reactions related to the SOC. An increase in the SOC caused a decrease in the thermal runaway initial temperature and the maximum increase in temperature. A higher SOC determined intense chemical reactions in the cell at higher temperatures, which caused a significant amount of materials to spew out of the batteries as well as additional mass loss. Relationships between failure characteristics and internal reactions were analyzed. The SOC should be lower than 50% in transportation or storage. The intercalated lithium capacities were the main reason for the series of domino reactions, which caused runaway in the terminal. These studies can serve as a reference for safety applications, transportation, and loss prevention in LIBs.