1,413 research outputs found
Electrochemistry as a correlation tool candidate with catalytic activities in Ru-catalyzed hydrolytic oxidation of organosilane
No full textElectrochemical parameters measured from a series of ruthenium complexes are nicely correlated with both structural changes and catalytic activities of those species under the reaction conditions providing a possibility that electrochemistry may offer a facile tool for better understanding of some transition metal-catalyzed reactions. (C) 2004 Elsevier Ltd. All rights reserved
Ammonium exchange and bioregeneration of bio-flocculated zeolite in a sequencing batch reactor
No full textNatural zeolite was added to the sequencing batch reactors to assess its role in ammonium exchange. Even though the biofilm was fully developed on the zeolite surface, ammonium removal and the biological regeneration of the zeolite occurred constantly during the anoxic-fill phase and the reaction phase, respectively. However, the specific nitrification rate of the bio-flocculated zeolite was lower than that observed in the control on account of the limited ammonium release to the liquid phase
Additional role of nicotinic acid hydroxylase for the transformation of 3-succinoyl-pyridine by Pseudomonas sp. JY-Q
No full textApplied Environmental Microbiology, 87, e02740-20Note : if this item contains full text it may be a preprint, author manuscript, or a Gold OA copy that permits redistribution with a license such as CC BY. The final version is available through the publisher’s platform.Nicotine and nicotinic acid (NA) are both considered to be representatives of N-heterocyclic aromatic compounds, and their degradation pathways have been revealed in Pseudomonas species. However, the cooccurrence of these two pathways has only been observed in Pseudomonas sp. strain JY-Q. The nicotine pyrrolidine catabolism pathway of strain JY-Q consists of the functional modules Nic1, Spm, and Nic2. The module enzyme, 3-succinoylpyridine monooxygenase (Spm), catalyzes transformation of 3-succinoyl-pyridine (SP) to 6-hydroxy-3-succinoyl-pyridine (HSP). There exist two homologous but not identical Spm enzymes (namely, Spm1 and Spm2) in JY-Q. However, when spm1 and spm2 were both in-frame deleted, the mutant still grew well in basic salt medium (BSM) supplemented with nicotine as the sole carbon/nitrogen nutrition, suggesting that there exists an alternative pathway responsible for SP catabolism in JY-Q. NicAB, an enzyme accounting for NA hydroxylation, contains reorganized domains similar to those of Spm. When the JY-Q_nicAB gene (nicAB in strain JY-Q) was introduced into another Pseudomonas strain, one that is unable to degrade NA, the resultant recombinant strain exhibited the ability to transform SP to HSP, but without the ability to metabolize NA. Here, we conclude that NicAB in strain JY-Q exhibits an additional role in SP transformation. The other genes in the NA cluster, NicXDFE (Nic2 homolog), then also exhibit a role in subsequent HSP metabolism for energy yield. This finding also suggests that the cooccurrence of nicotine and NA degradation genes in strain JY-Q represents an advantage for JY-Q, making it more effective and flexible for the degradation of nicotine.China Postdoctoral Science Foundationhttps://login.libproxy.rpi.edu/login?url=https://doi.org/10.1128/AEM.02740-2
CANONICAL ABERRATION THEORY FOR CALCULATING HIGHER-ORDER CHROMATIC ABERRATIONS
No full textCanonical aberration theory has been developed in previous papers by the author. In the present study, the canonical aberration theory has been used to deal with first- and third-order chromatic aberrations (including position and momentum aberrations at an arbitrary observation plane) for rotationally symmetrical optical systems. All first- and third-order chromatic aberrations have been expressed in canonical matrix representations, which are general in nature and appropriate for computer calculations.Physics, AppliedSCI(E)3ARTICLE41962-19676
Selecive Catalytic Reduction of NOx in Lean Burn Engine Exhaust by Highly Active Pt Supported on V-impregnated MCM-41
No full textOn the Pt/V/MCM-41 catalyst with 1wt% Pt and 4wt% V, the maximum conversion of NO reduction into N2+N2O by C3H6 was about 73%, which was 10% higher than on 1wt% Pt/silica, and this maximum conversion was maintained over a temperature range of 70.DEG.C. between 270 and 340.DEG.C.. (author abst.
Keratinocyte-derived circulating microRNAs in extracellular vesicles: a novel biomarker of psoriasis severity and potential therapeutic target
No full textBackground: Psoriasis is a chronic inflammatory disorder characterized by pathogenic hyperproliferation of keratinocytes and immune dysregulation. Currently, objective evaluation tools reflecting the severity of psoriasis are insufficient. MicroRNAs in extracellular vesicles (EV miRNAs) have been shown to be potential biomarkers for various inflammatory diseases. Our objective was to investigate the possibility of plasma-derived EV miRNAs as a marker for the psoriasis disease severity. Methods: EVs were extracted from the plasma of 63 patients with psoriasis and 12 with Behçet’s disease. We performed next-generation sequencing of the plasma-derived EV miRNAs from the psoriasis patients. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to validate the level of EV miRNA expression. In situ hybridization was used to discern the anatomical location of miRNAs. qRT-PCR, western blotting, and cell counting kits (CCKs) were used to investigate IGF-1 signaling in cells transfected with miRNA mimics. Results: We identified 19 differentially expressed EV miRNAs and validated the top three up-and down-regulated EV miRNAs. Among these, miR-625-3p was significantly increased in patients with severe psoriasis in both plasma and skin and most accurately distinguished moderate-to-severe psoriasis from mild-to-moderate psoriasis. It was produced and secreted by keratinocytes upon stimulation. We also observed a significant intensification of IGF-1 signalling and increased cell numbers in the miR-625-3p mimic transfected cells. Conclusions: We propose keratinocyte-derived EV miR-625-3p as a novel and reliable biomarker for estimating the severity of psoriasis. This biomarker could objectively evaluate the severity of psoriasis in the clinical setting and might serve as a potential therapeutic target. Trial registration None
Differential effect of homologous NicR2A/NicR2Bs and endogenous ectopic strong promoters on nicotine metabolism in Pseudomonas sp. JY-Q
No full textApplied Environmental Microbiology, 87, e02457-20Note : if this item contains full text it may be a preprint, author manuscript, or a Gold OA copy that permits redistribution with a license such as CC BY. The final version is available through the publisher’s platform.Nicotine is a toxic environmental pollutant that widely exists in tobacco wastes. As a natural nicotine-degrading strain, Pseudomonas sp. strain JY-Q still has difficulties degrading high concentrations of nicotine. In this study, we investigated the effect of two homologous transcriptional regulators and endogenous ectopic strong promoters on the efficiency of nicotine degradation. Comparative genomics analysis showed that two homologous transcriptional regulators, namely, NicR2A and NicR2Bs (NicR2B1 plus NicR2B2), can repress nicotine degradation gene expression. When both nicR2A and nicR2Bs were deleted, the resulting mutant JY-Q ΔnicR2A ΔnicR2B1 ΔnicR2B2 (QΔABs) exhibits a 17% higher nicotine degradation efficiency than wild-type JY-Q. Transcriptome sequencing (RNA-seq) analysis showed that the transcription levels (fragments per kilobase per million [FPKM] value) of six genes were higher than those of the other genes in JY-Q. Based on the genetic organization of these genes, three putative promoters, PRS28250 , PRS09985 , and PRS24685 , were identified. Their promoter activities were evaluated by comparing their expression levels using reverse transcriptase quantitative PCR (RT-qPCR). We found that the transcription levels of RS28250, RS09985, and RS24685 were respectively 16.8, 2.6, and 1.6 times higher than that of hspB2, encoding 6-hydroxy-3-succinylpyridine hydroxylase, which is involved in nicotine degradation. Thus, two strong endogenous promoters, namely, PRS28250 and PRS09985 , were selected to replace the original promoters of nic2 gene clusters. The effect of the endogenous ectopic promoter was also related to the position of target gene clusters. When the promoter PRS28250 replaced the promoter of hspB2, the resultant mutant QΔABs-ΔPhspB
Expression and functional identification of two homologous nicotine dehydrogenases, NicA2 and Nox, from Pseudomonas sp. JY-Q
No full textProtein Expression and Purification, 178, 105767Note : if this item contains full text it may be a preprint, author manuscript, or a Gold OA copy that permits redistribution with a license such as CC BY. The final version is available through the publisher’s platform.Nicotine contamination in tobacco waste effluent (TWE) from tobacco industry is a serious threat to public health and environment. Microbial degradation is an impending approach to remove nicotine and transform it into some other high value chemicals. Pseudomonas sp. JY-Q exhibits high efficiency of degradation, which can degrade 5 g/L of nicotine within 24 h. In strain JY-Q, we found the co-occurrence of two homologous key enzymes NicA2 and Nox, which catalyze nicotine to N-methylmyosmine, and then to pseudooxylnicotine via simultaneous hydrolysis. In this study, recombinant NicA2 and Nox were expressed in E. coli BL21(DE3) and purified. In vitro, the activity of recombinant NicA2 and Nox was accelerated by adding co-factor NAD+, suggesting that they worked as dehydrogenases. The optimal reaction conditions, substrate affinity, catabolism efficiency, pH-stability and thermal-stability were determined. Nox showed lower efficiency, but at a higher stability level than NicA2. Nox exhibited wider pH range and higher temperature as optimal conditions for the enzymatic reaction. In addition, The Nox showed higher thermo-stability and acid-stability than that of NicA2. The study on enzymatic reaction kinetics showed that Nox had a lower Km and higher substrate affinity than NicA2. These results suggest that Nox plays more significant role than NicA2 in nicotine degradation in TWE, which usually is processed at low pH (4–5) and high temperature (above 40 °C). Genetic engineering is required to enhance the affinity and suitability of NicA2 for an increased additive effect on homologous NicA2 and Nox in strain JY-Q.National Natural Science Foundation of Chinahttps://login.libproxy.rpi.edu/login?url=https://doi.org/10.1016/j.pep.2020.10576
Reduced hole mobility due to the presence of excited states in poly-(3-hexylthiophene)
No full textCopyright 2007 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. This article appeared in Applied Physics Letters 93, 233306 (2008) and may be found at
Effects of the complex mass distribution of dark matter halos on weak-lensing cluster surveys
No full textGravitational lensing effects arise from the light-ray deflection by all of the mass distribution along the line of sight. It is then expected that weak-lensing cluster surveys can provide us with true mass-selected cluster samples. With numerical simulations, we analyze the correspondence between peaks in the lensing convergence kappa-map and dark matter halos. In particular, we emphasize the difference between the peak kappa-value expected from a dark matter halo modeled as an isolated and spherical one, which exhibits a one-to-one correspondence with the halo mass at a given redshift, and that of the associated kappa-peak from simulations. For halos with the same expected kappa, their corresponding peak signals in the kappa-map present a wide dispersion. At an angular smoothing scale of theta(G) = 10, our study shows that for relatively large clusters, the complex mass distribution of individual clusters is the main reason for the dispersion. The projection effect of uncorrelated structures does not play significant roles. The triaxiality of dark matter halos accounts for a large part of the dispersion, especially for the tail on the high-kappa side. Thus, lensing-selected clusters are not really mass-selected. To better predict kappa-selected cluster abundance for a cosmological model, one has to take into account the triaxial mass distribution of dark matter halos. On the other hand, for a significant number of clusters, their mass distribution is even more complex than that described by the triaxial model. Our analyses find that large substructures affect the identification of lensing clusters considerably. They could show up as separate peaks in the kappa-map and cause a misassociation of the whole cluster with a peak resulting only from a large substructure. The lower end dispersion of kappa is attributed mostly to this substructure effect. For theta(G) = 20, the projection effect can be significant and contributes to the dispersion at both high- and low-kappa ends.Astronomy & AstrophysicsSCI(E)0ARTICLE160-7263
- …
