Mechanism of Klebsiella pneumoniae resistance to carbapenem antibiotics

Purpose: To investigate the mechanism of action of Klebsiella pneumoniae (Kpn) resistance to carbapenem. Methods: The susceptibility of six Klebsiella pneumoniae strains to antibiotics was determined using KB assay. Six isolated strains which were resistant to carbapenem were identified and collected using modified Hodge test. The phenotypes of metal enzyme were evaluated by ethylene diamine tetraacetic acid (EDTA) disk diffusion method. The genes for beta-lactamases, including KPC gene, were examined. Results: The six carbapenem-resistant strains of Klebsiella pneumoniae were resistant to imipenem, meropenem and aztreonam, but were sensitive to amikacin, fosfomycin, minocycline, and polymyxin. The six pathogens did not produce metal enzyme, but they produced carbapenemases. Moreover, the six strains partially carried blaTEM or blaSHV gene, but all had blaKPC-2 gene. Conclusion: These results suggest that the pathogens that contain blaKPC-2 gene may be involved in the mechanism of Klebsiella pneumoniae (Kpn) resistance to carbapenem

Photocatalytic Activation of Saturated C–H Bond Over the CdS Mixed-Phase Under Visible Light Irradiation

Selective activation of saturated C–H bond in hydrocarbons to produce high-value-added chemicals is of great significance for chemical synthesis and transformation. Herein, we present a facile procedure to achieve Ni-doped CdS nanoparticles with mixed (cubic and hexagonal) phases, as well as its application to the photocatalytic activation of saturated primary C–H bond of toluene and its derivatives. The photocatalytic oxidation rate of toluene into benzaldehyde of formation reached up to 216.7 μmolh−1g−1 under visible light irradiation. The excellent photocatalytic performance of Ni(II)-doped CdS [Ni(II)/CdS] can be attributed to its unique structural assembly with cubic and hexagonal phases and also the addition of Ni ions, together taking effect in promoting the separation of photogenerated charge carriers. The possible reaction mechanism for the photocatalytic selective oxidation is illustrated in this work. The band width of the as-prepared mixed phase CdS is reduced, which can effectively expand the response range and improve photocatalytic performance

Biological N fixation but not mineral N fertilization enhances the accumulation of N in peanut soil in maize/peanut intercropping system

Legume/cereal intercropping has the potential to maximize the use of resources to raise yields due to enhanced nitrogen (N) fixation by legume root nodules, while high N fertilization may inhibit the nodulation of legume. However, whether legume/cereal intercropping can promote the accumulation of soil N storage with N fertilization and its underlying mechanism are less clear. Here, we evaluated the long-term (5 years) effects of maize/peanut intercropping and mineral N fertilization on peanut soil total N content and soil N cycling functional genes. The experiment includes two planting patterns (peanut maize intercropping and peanut monocropping) with three N fertilization rates (0, 150, and 300 kg N ha−1). Intercropping increased soil total N content (STN) by average 18.2%, and the positive effect of intercropping on STN decreased with N application rate. Highest N application decreased the nodule fresh weight (NFW) by 64.3% and 46.0% in intercropping and monocropping system, respectively. However, intercropping has no effect on NFW. Intercropping increased the nifH gene abundance by average 26.5%. SEM analysis indicated that NFW and nifH gene abundance combined can explain 46% of the variance of STN. Our results indicate that biological N fixation but not mineral N fertilization enhances the accumulation of N in soil planted with peanut in maize/peanut intercropping system.info:eu-repo/semantics/publishedVersio

Pressure Relief and Bolt Grouting Reinforcement and Width Optimization of Narrow Coal Pillar for Goaf-Side Entry Driving in Deep Thick Coal Seam: A Case Study

Goaf-side roadway driving with narrow coal pillars could obviously improve coal resource recovery rates compared with traditional large, wide pillars, and this is pivotal to the sustainable development of underground mines. However, it is very difficult to control the stability of goaf-side roadway driving, especially in deep, thick coal seams with large and high working faces. In order to control the stability of goaf-side entry driving in working face 210106 of the deep and thick coal seam in Xinji No. 2 Coal Mine in Anhui Province of China, we carried out field investigations, theoretical calculations, numerical simulations, and an engineering practice to identify the main factors influencing the deformation of the surrounding rock in order to optimize the width of the narrow coal pillar and to propose countermeasures for goaf-side entry driving. Our results show that the main factors influencing deformation of the rock surrounding the roadways at working face 210106 in Xinji No. 2 Coal Mine include high ground stress, large mining height, thick sandstone in the roof, and the residual abutment pressure of the adjacent goaf. The results obtained from theoretical calculations, the numerical simulations, and the engineering practice indicate that a 5 m-wide coal pillar is relatively appropriate and feasible. The countermeasures of pressure relief by blasting roof cutting and bolt grouting reinforcement were carried out to control the stability for goaf-side entry driving. Field measurements indicated that deformations of goaf-side entry driving in deep, thick coal seams could be efficiently controlled. The maximum deformations of sidewall-to-sidewall and roof-to-floor were 100 mm and 350 mm, respectively

Pressure Relief and Bolt Grouting Reinforcement and Width Optimization of Narrow Coal Pillar for Goaf-Side Entry Driving in Deep Thick Coal Seam: A Case Study

Goaf-side roadway driving with narrow coal pillars could obviously improve coal resource recovery rates compared with traditional large, wide pillars, and this is pivotal to the sustainable development of underground mines. However, it is very difficult to control the stability of goaf-side roadway driving, especially in deep, thick coal seams with large and high working faces. In order to control the stability of goaf-side entry driving in working face 210106 of the deep and thick coal seam in Xinji No. 2 Coal Mine in Anhui Province of China, we carried out field investigations, theoretical calculations, numerical simulations, and an engineering practice to identify the main factors influencing the deformation of the surrounding rock in order to optimize the width of the narrow coal pillar and to propose countermeasures for goaf-side entry driving. Our results show that the main factors influencing deformation of the rock surrounding the roadways at working face 210106 in Xinji No. 2 Coal Mine include high ground stress, large mining height, thick sandstone in the roof, and the residual abutment pressure of the adjacent goaf. The results obtained from theoretical calculations, the numerical simulations, and the engineering practice indicate that a 5 m-wide coal pillar is relatively appropriate and feasible. The countermeasures of pressure relief by blasting roof cutting and bolt grouting reinforcement were carried out to control the stability for goaf-side entry driving. Field measurements indicated that deformations of goaf-side entry driving in deep, thick coal seams could be efficiently controlled. The maximum deformations of sidewall-to-sidewall and roof-to-floor were 100 mm and 350 mm, respectively

NIK-SIX1 signalling axis regulates high glucose-induced endothelial cell dysfunction and inflammation

Endothelial dysfunction and inflammation are the main manifestations of diabetes-associated atherosclerosis. This paper studied the roles of NF-κB-inducing kinase (NIK) and sine oculis homeobox homolog 1 (SIX1) in regulating high glucose-induced endothelial dysfunction and inflammation. The expression of NIK and SIX1 in human umbilical vein endothelial cells (HUVECs) was silenced by transfection with the specific shRNAs. HUVECs exposed to high glucose were considered as a cell model of endothelial dysfunction. Expression of NIK and SIX1 following transfection was measured by qRT-PCR and western blotting analysis. The proliferation, migration, and inflammation of HUVECs were evaluated by EdU staining, scratch test, ELISA, and western blotting. High glucose (30 mM) significantly decreased the proliferation and migration of HUVECs. High glucose-induced the expression of adhesion molecules VCAM-1 and ICAM-1. Moreover, high glucose increased the release of IL-1β, IL-6, TNF-α, and MCP-1. Transfection of cells with NIK shRNA significantly reversed the toxic effects of high glucose on HUVECs. Of contrast, SIX1 shRNA accelerated the effects of high glucose on HUVECs. NIK shRNA inhibited the accumulation of RelA, RelB, and p52. Meanwhile, NIK shRNA led to SIX1 downregulation which further induced the activation of the NF-κB pathway. NIK-SIX1 signalling axis was suggested to be critical in the regulation of high glucose-induced endothelial dysfunction and inflammation. SIX1 may function as an immunological gatekeeper to control the excessive inflammation mediated by NIK in diabetes-associated atherosclerosis

Is 18F-PET-CT the First Choice for Preoperative Screening for Ia Non-small Cell Lung Cancer?

Background and objective The preferred therapy for patients with pulmonary nodules which highly suspected as lung cancer by low-dose spiral computed tomography (CT) is surgery, but the best screening method of whole body is not clear yet. The aim of this study is to investigate the differences in the progression-free survival (PFS) of patients with Ia stage non-small cell lung cancer after screening of positron emission computed tomography (PET)-CT and conventional imaging (B-ultrasound/CT/MRI/ECT, BCME). Methods A total of 300 cases of Ia stage non-small cell lung cancer were collected, of which 170 cases were performed PET-CT and 130 cases were performed BCME before operation. The basic characteristics of the two groups were analyzed by propensity score matching (PSM), and 114 cases of each group were included in the study. The survival analysis was carried out by the Kaplan-Meier survival curve and the Cox regression analysis. Results There was no significant difference between each group analyzed by PSM. The PFS of PET-CT and BCME were (44.9±27.2) months and (44.1±33.1) months (χ2=1.284, P=0.257). Both of the method ssucceed in screening. It is not the PFS influence factors. The false positive of PET-CT and BCME were 10 cases and 8 cases (χ2=0.241, P=0.623). Conclusion Both PET-CT and BCME can be used as a screening method for Ia stage non-small cell lung cancer according to individualized choice of patients

Association of Serum Myeloid Cells of Soluble Triggering Receptor-1 Level with Myocardial Dysfunction in Patients with Severe Sepsis

Objective. To investigate the association of serum sTREM-1 with myocardial dysfunction in patients with severe sepsis. Methods. A total of 85 patients with severe sepsis were divided into severe sepsis group (n=40) and septic shock group (n=45). Serum levels of sTREM-1, NT-proBNP, APACHE II score, SOFA score, cardiac index, cardiac function index, global ejection fraction, and left ventricular contractility index were measured on days 1, 3, and 7 after admission to ICU. Results. Serum sTREM-1 levels of patients with septic shock were significantly higher than those with severe sepsis on days 1, 3, and 7. Serum sTREM-1 was positively correlated with APACHE II scores, SOFA scores, and NT-proBNP. However, The sTREM-1 level was markedly negatively correlated with CI, CFI, GEF, and dP/dt max, respectively. Multiple logistic regression analysis showed that sTREM-1 was independent risk factor to NT-proBNP increasing. The optimal cut-off point of sTREM-1 for detecting patients with myocardial dysfunction was 468.05 ng/mL with sensitivity (80.6%) and specificity (75.7%). There is no difference in TREM-1-mRNA expression between the two groups. Conclusions. Serum sTREM-1 is significantly associated with myocardial dysfunction and may be a valuable tool for determining the presence of myocardial dysfunction in patients with severe sepsis