Liuthomsen0222

Gold nanoclusters decorated amine-functionalized graphene oxide (Au-GO-NH2) nanosheets were designed as a highly efficient visible light active antibacterial agent. This assembled nanosheet is positively charged and of high specific surface area that captures bacteria through physical adsorption and electrostatic interaction. Under visible light irradiation, this photoactive nanosheet concurrently generates massive heat and produces substantial reactive oxygen species to inactivate bacteria. In comparison with bare gold nanoclusters and amine-functionalized graphene oxides, this nanosheet appears an enhanced antibacterial activity >5-fold towards Gram-postive and Gram-negative bacteria. Moreover, a nanosheet modified silicone surface was employed as a model of implant devices, which showed superior antibacterial efficacy against bacterial colonization in vitro. This work demonstrates that the assembled nanosheet is a promising novel strategy in the construction of next generation antimicrobial agent for synergistic bacterial capture, oxidative stress, and photothermal ablation in the biomedical and environmental fields.Bioaccumulation and toxicity of per-and polyfluoroalkyl substances and metal in plants have been confirmed, however their contamination in soil and plants still requires extensive investigation. In this study the combined effects of chlorinated polyfluoroalkyl ether potassium sulfonate (F53B) and chromium (Cr) on water spinach (Ipomoea aquatica Forsk) were investigated. Compared with each single stress, the combination of F53B and Cr (VI) reduced the biomass and height and increasingly accumulated in the roots and destroyed the cell structure. Besides, the co-contamination led to the immobilization of F53B and Cr (VI) in soil, which affected their migration in soil and transfer to plants. The antioxidant response and photosynthesis of the plant weakened under the single Cr (VI) and enhanced under the single F53B treatment; however the contamination of F53B and Cr (VI) could also reduce this effect, as confirmed by the gene expression of MTa, psbA and psbcL genes. This study provides an evidence of the environmental risks resulting from the coexistence of F53B and Cr (VI).The global increase of food production has been achieved mainly through the intensive use of inputs such as pesticides. Once released to the soil, sorption (which could be represented by Freundlich solid-water distribution coefficients - KF) and degradation are two governing processes that determine the distribution and persistence of pesticides in the environment. In spite of the huge dataset, the only apparent generalisation is the high correlation between KF and soil organic matter (SOM) content. However, in this work no correlation was observed between KF and organic C content (OC) and so the obtained KOC (KF normalised by OC) spread out in a wide range 1100 to 11,400 mL g-1 for abamectin; and 30-150 mL g-1 for atrazine, both ranges corroborate with data from literature. These high variabilities indicate that other soil components or SOM quality strongly interfere in the pesticide sorption in addition to SOM content. Seeking to estimate the influence of SOM quality in the abamectin and atrazine KOC values, the humic acids, a fraction of the SOM, was analysed by 13C nuclear magnetic resonance spectroscopy (13C NMR) and Principal Component (PC) Regression. Diphenyleneiodonium cell line The first PC of 13C NMR spectra presented negative loadings for aliphatic compounds and positive loadings for aryl C, typical of partially oxidised pyrogenic C. Their scores showed strong correlation with the abamectin KOC values (R2 = 0.91, p less then 5 10-8) and weaker with atrazine KOC (R2 = 0.63, p less then 0.0001), in addition to a smaller standardised slope 1.01 for abamectin and 0.76 for atrazine. These results could be explained by the higher hydrophobicity of abamectin, being thus more prone to interact with the polycondensed aryl groups from the pyrogenic C. It is also important to highlight that humic acids are useful proxies for understanding the paramount interaction of SOM with pesticides.The toxicity of neonicotinoid insecticide imidacloprid (IMI) to mammals has recently received increasing attention. However, the effects of IMI on the gut barrier and liver function of male C57BL/6J mice are still unknown. The study showed that exposure to IMI could reduce relative liver weights, change hepatic tissue morphology and induce hepatic oxidative stress. The gut barrier function was greatly impaired by IMI exposure, which might increase the body's susceptibility to harmful substances in the gut. Meanwhile, the synthesis and metabolism of hepatic bile acids (BAs) was also affected by IMI exposure. The levels of serum and hepatic total bile acids (TBAs) decreased; in contrast, the fecal TBA levels increased after exposure to 30 mg/L IMI for 10 weeks. Sequencing of colonic contents revealed that the operational taxonomic units (OTUs) and α-diversity index increased and that the gram-negative bacteria overgrew, indicating that the balance of the gut microbiota was disrupted. The present study indicated that subchronic exposure to IMI interfered with the gut barrier function, interfering with BAs metabolism and causing gut microbiota imbalance in male C57BL/6J mice. Taken together, IMI residues appear to be potentially toxic to mammals and even humans.The distribution of polycyclic aromatic hydrocarbons (PAHs) in the surface water and sediments in five regions of the Indian Sundarbans was assessed. The capability of microbial biofilm communities to sequester PAHs in a biofilm-promoting vessel was evaluated. The total PAH concentration of water and sediments ranged from undetectable to 125 ng ml-1 and 4880 to 2 × 104 ng g-1 dry weight respectively. The total PAHs concentration of sediments exceeded the Effects Range-Low value and the recommended Effects Range-Median values, implying the PAHs might adversely affect the biota of the Sundarbans. Pyrogenic and petrogenic sources of PAH contamination were identified in most of the sampling sites. Indigenous biofilms were cultivated in a patented biofilm-promoting culture vessel containing liquid media spiked with 16 priority PAHs. Biofilm-mediated 97-100% removal efficiency of 16 PAHs was attained in all media. There was no significant difference between the mean residual PAH from the liquid media collected from hydrophobic and hydrophilic flasks. Residual amounts of acenaphthene (Ace), anthracene (Ant), benzo(b)fluoranthene [B(b)F], benzo(a)pyrene [B(a)P] and benzo(g,h,i)perylene [B(g,h,i)P] showed differences when cultivated in hydrophobic and hydrophilic flasks. The mean residual amounts of total PAHs extracted from biofilm biomasses were variable. A biofilm obtained from a specific sampling site cultured in the hydrophobic flask showed higher PAH sequestration when compared to the removal attained in the hydrophilic flask. Relative abundances of different microbial communities in PAH-sequestering biofilms revealed bacterial phyla including Proteobacteria, Bacteroidetes, Firmicutes, Actinobacteria, Chloroflexi and Planctomycetes as well as members of Ascomycota phylum of fungi. The dominance of Candida tropicalis, Clostridium butyricum, Sphingobacterium multivorum and Paecilomyces fulvus were established.Starch retrogradation resulted in bad performance and taste of starch products. In this study, the corn starch films modified by sodium adipate and triethylene glycol were prepared by solution casting. The retrogradation of modified starch films were studied by FT-IR, XRD, SEM, tension test and UV-Vis. The results showed that sodium adipate was more effective than triethylene glycol in inhibiting the short-term retrogradation of starch, and triethylene glycol was more effective than sodium adipate in inhibiting the long-term retrogradation of starch. However, the mixture of sodium adipate and triethylene glycol, especially 15% adipic acid and 10% triethylene glycol, showed synergistic effects on the short-term and long-term retrogradation of starch. The starch film with 15% adipic acid and 10% triethylene glycol had the highest elongation at break, the best transmittance, the lowest change rate of elongation at break, and the lowest moisture content among all the recipes.Probiotic lactobacilli have been implicated in the production of many low molecular weight bioactive molecules with tremendous potential to kill multidrug resistant human pathogens. The aim of the present study is to purify, characterise and evaluate a novel compound produced by a probiotic Lactobacillus plantarum LJR13 strain. The compound was purified employing silica gel column chromatography followed by RP-HPLC technique. The compound was identified as tert-butyl-4-(4-oxo-(2-((2-oxo-1- (p-tolyl) -2- (p-tolyloxy) ethyl) carbamoyl) pyrrolidin-1-yl) butanoyl) piperazine-carboxylate (BPBP) through various spectral techniques. Exhaustive literature search has revealed that the compound BPBP has not been reported from Lactobacillus species so far and ours is the first report describing its spectrum of activities against multidrug resistant human pathogens together with the morphological and physiological manifestations it brings about in the normal as well as human colon carcinoma cells. The MIC of BPBP for Listeria monocytogenes and Staphylococcus aureus was 15.62 μg/mL and 62.50 μg/mL respectively; however, for Acinetobacter baumannii the MIC was determined to be 31.25 μg/mL. Scanning electron microscopic studies of BPBP treated L. monocytogenes, S. aureus, and A. baumannii revealed the presence of blebs on the cell wall which represents the compromise in the cell wall integrity. While BPBP showed no significant cytotoxicity on mouse embryonic fibroblast cells, (NIH-3T3), marked discernible cytotoxic effect was observed on colorectal carcinoma cells, HCT-116, suggesting potential anti-cancer activity. Molecular docking studies displayed the interaction of BPBP with appropriate drug resistance associated proteins such as Penicillin binding proteins in gram positive L. monocytogenes and S. aureus and beta-lactamase in gram negative A. baumannii.

Typical clinical data can suffer routine information loss when event times are rounded to the nearest day and right-censored at the end of follow-up. Because of the daily basis recording system, for the first 24h, there are no events, which can damage the estimation of the Weibull survival model. link2 Its estimation bias is inevitable since, for this short period, massive events might have occurred, the data is missing, and the fitted Weibull model is to show a steep slope. This phenomenon of estimation bias caused by the information loss caused by the problem of measurement resolution has not been properly discussed so far.

We propose a partial imputation Expectation Maximization (PIEM)-algorithm to estimate missing lifetimes only for day 1 at the mode among the whole clinical follow-up days. Based on various Weibull distributions, we simulated clinical sets after rounding and censoring raw event times and prepared chimera sets by partially substituting the imputed lifetimes only for the 24h at the mode among the entire clinical sets.

For shape parameter ≤ 1, almost all the 95% prediction intervals (PIs) of both parameters in the chimera sets include their true values, while those in the clinical sets miss most of the true shape parameters and some of the true scale parameters. link3 Estimating a small proportion of missing data only for the 24h period, while keeping the rest as they are, greatly reduces biases of both scale and shape parameters. For shape parameter >1, the chimera sets consistently outperform the clinical sets.

The PIEM-algorithm may be applied as an intuitive tool for time-to-event modeling of survival data with this kind of information loss.

The PIEM-algorithm may be applied as an intuitive tool for time-to-event modeling of survival data with this kind of information loss.