41 research outputs found
Toxicological assessment of multi-walled carbon nanotubes combined with nonylphenol in male mice
<div><p>Carbon nanotubes have attracted increasing attention attributable to their widespread application. To evaluate the joint toxicity of multi-walled carbon nanotubes (MWCNTs) and nonylphenol (NP), we investigated the toxicological effects of NP, pristine MWCNTs, and MWCNTs combined with NP in male mice. After exposing male mice by gavage for 5 days, intracellular superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, as well as malondialdehyde (MDA) and glutathione (GSH) levels in tissues were determined to evaluate <i>in vivo</i> oxidative stress. In addition, genotoxicity was assessed by examining DNA damage in mouse liver and sperm via the comet assay, and transmission electron microscopy (TEM) was used for direct visual observations of mitochondrial damage in the liver. Results from the oxidative damage and DNA damage experiments indicate that after adsorbing NP, MWCNTs at a high dose induce oxidative lesions in the liver and cause DNA damage in mouse sperm; these data offer new insights regarding the toxicological assessment of MWCNTs.</p></div
Transmission electron microscopy (TEM) micrograph of multi-walled carbon nanotubes (MWCNTs).
<p>Transmission electron microscopy (TEM) micrograph of multi-walled carbon nanotubes (MWCNTs).</p
Superoxide dismutase (SOD) activity in the organs of mice.
<p>Results are expressed as the means ± SD (n = 5). Significant differences from the control (CK) group are denoted by * <i>p</i> < 0.05 and ** <i>p</i> < 0.01.</p
Photoinduced Palladium-Catalyzed 1,2-Difunctionalization of Electron-Rich Olefins via a Reductive Radical-Polar Crossover Reaction
Palladium-catalyzed cross-coupling reactions belong to
the most
important transformations for the construction of C–C or C-heteroatom
bonds. More recently, the photochemical activation of palladium complexes
emerged as a key strategy to leverage palladium catalysis at room
temperature beyond the scope of conventional cross-coupling chemistry.
Herein, we report on the photoinduced palladium-catalyzed 1,2-difunctionalization
reaction of electron-rich olefins. Mechanistic experiments and computational
studies reveal that this reaction proceeds via the addition of an
alkyl radical, followed by the oxidation of a radical intermediate
to access carbocation intermediates, which are inaccessible via classic
thermal reaction conditions. The carbocation can then be applied to
a variety of secondary C–C or C–N bond-forming reactions.
This strategy now allows a general approach toward densely functionalized
unsymmetric 1,1-bis(heterocyclyl)alkanes
Photoinduced Palladium-Catalyzed 1,2-Difunctionalization of Electron-Rich Olefins via a Reductive Radical-Polar Crossover Reaction
Palladium-catalyzed cross-coupling reactions belong to
the most
important transformations for the construction of C–C or C-heteroatom
bonds. More recently, the photochemical activation of palladium complexes
emerged as a key strategy to leverage palladium catalysis at room
temperature beyond the scope of conventional cross-coupling chemistry.
Herein, we report on the photoinduced palladium-catalyzed 1,2-difunctionalization
reaction of electron-rich olefins. Mechanistic experiments and computational
studies reveal that this reaction proceeds via the addition of an
alkyl radical, followed by the oxidation of a radical intermediate
to access carbocation intermediates, which are inaccessible via classic
thermal reaction conditions. The carbocation can then be applied to
a variety of secondary C–C or C–N bond-forming reactions.
This strategy now allows a general approach toward densely functionalized
unsymmetric 1,1-bis(heterocyclyl)alkanes
Toxicological assessment of multi-walled carbon nanotubes combined with nonylphenol in male mice - Fig 7
<p>Tail DNA (A) and olive tail moment (OTM) (B) from the comet assay in mouse sperm after exposure to saline only (CK control), dimethyl sulfoxide (DMSO), 4-nonylphenol (NP), multi-walled carbon nanotubes (MWCNTs), and MWCNTs+NP. The values are means ± SD (n = 5). Significant differences from the CK group are denoted by ** <i>p</i> < 0.01 and *** <i>p</i> < 0.001.</p
Malondialdehyde (MDA) content in the organs of mice.
<p>Results are expressed as the means ± SD (n = 5). Significant differences from the control (CK) group are denoted as * <i>p</i> < 0.05 and ** <i>p</i> < 0.01.</p
DataSheet1_Development of QSRR model for hydroxamic acids using PCA-GA-BP algorithm incorporated with molecular interaction-based features.pdf
As a potent zinc chelator, hydroxamic acid has been applied in the design of inhibitors of zinc metalloenzyme, such as histone deacetylases (HDACs). A series of hydroxamic acids with HDAC inhibitory activities were subjected to the QSRR (Quantitative Structure–Retention Relationships) study. Experimental data in combination with calculated molecular descriptors were used for the development of the QSRR model. Specially, we employed PCA (principal component analysis) to accomplish dimension reduction of descriptors and utilized the principal components of compounds (16 training compounds, 4 validation compounds and 7 test compounds) to execute GA (genetic algorithm)-BP (error backpropagation) algorithm. We performed double cross-validation approach for obtaining a more convincing model. Moreover, we introduced molecular interaction-based features (molecular docking scores) as a new type of molecular descriptor to represent the interactions between analytes and the mobile phase. Our results indicated that the incorporation of molecular interaction-based features significantly improved the accuracy of the QSRR model, (R2 value is 0.842, RMSEP value is 0.440, and MAE value is 0.573). Our study not only developed QSRR model for the prediction of the retention time of hydroxamic acid in HPLC but also proved the feasibility of using molecular interaction-based features as molecular descriptors.</p
Additional file 1 of Improved consolidated bioprocessing for itaconic acid production by simultaneous optimization of cellulase and metabolic pathway of Neurospora crassa
Additional file 1: Figure S1. Main plasmids used in this study. (A) Plasmids pMF-272-Pccg1/Peas/Pcbh1/Pgh6-2/Pgh11-2/Ptef1/Pgpd/Ppda-CAD were used to compare the expression of CAD in N. crassa. (B) Plasmids pMF-272-Pccg1-CBH1/GH6-2/GH5-1/GH3-4/AsBGA/TrCBH2 were used to compare the effects of different cellulases. (C) Plasmids pMF-272-Pccg1-CAD-Pcbh1-CBH1/GH6-2/GH5-1/GH3-4/AsBGA/TrCBH2 were used to compare the effects of different cellulase and CAD co-expression. (D) Plasmid pMF-272-Pccg1-MTK was used to verify the expression of MTK in N. crassa. The plasmids pUC19-MTK-HPH (F) and pMF-272-Pccg1-CAD-Pes-MCL (E) or pMF-272-Pccg1-CAD-Pcbh1-MTTA-Pes-MCL (G) were used to construct N. crassa PMF-CAD-rGS or N. crassa PMF-CAD-MTTA-rGS. (H) Plasmid pMF-272-Pccg1-CAD-Pcbh1-MTTA-Pcbh1-TrCBH2 was used to construct N. crassa PMF-CAD-MTTA-TrCBH2. Figure S2. PCR amplified the promoter sequence. Figure S3. Strain construction process using Pcbh1 as the CAD promoter. (A) Pcbh1 promoter sequence was amplified by PCR. M:Trans2K Plus DNA Marker, 1–6:Pcbh1 (B) PCR identification of vector Blunt-Pcbh1. 1–22: Blunt-Pcbh1 (C) Identification of recombinant plasmid pMF272-CAD. 1–6: pMF272-CAD. (D) Double enzyme digestion of pMF272-CAD recombinant plasmid. (E) Cloning vector Blunt-Pcbh1 double enzyme digestion. (F) Colony PCR identification of recombinant plasmid pMF-CAD-Pcbh1. Figure S4. Construction of cellulase overexpression strain. (A) PCR amplification of Pcbh-1 promoter sequence (1 and 2), gh3-4 sequence (4), and cbh1 sequence (B, 1 and 2). (C) Identification of expression vector containing cbh1 gene. (D) PCR screening of gh3-4 gene expression vectors. (E) Genome PCR for vector transformation screening 1,2,3: cbh1; 4,5: gh3-4. Figure S5. Construction of MTK, MCL expression strain. (A) PCR amplification of MTK (lines 1 ~ 3). (B) Colony PCR for identification of MTK expression cassette (C) PCR amplification of GFP (1) and terminator fragments (2). Identification of expression vector containing cbh1 gene. Genome PCR for MTK expression (D) and MCL expression (E) vector transformation screening. Figure S6. Construction of CAD, MTK and MCL co-expression strain. (A) PCR amplification of 5′ fragment (lines 1 ~ 3). (B) PCR amplification of 3′ fragment (lines 1 ~ 3) and hph fragment (lines 4 and 5). (C) PCR amplification of MTK cassette. (D) Identification of expression vector containing 5′ fragment and hph fragment. Table S1. Plasmids used in this study. Table S2. Strains used in this study. Table S3. Primer list of CAD expression and promoter optimization. Table S4. Primer list of cellulase expression. Table S5. Primer list of CAD and cellulase co-expression. Table S6. Primer list of MTK, MCL and MTTA expression. Table S7. RT-PCR Primers
Ni/graphene Nanostructure and Its Electron-Enhanced Catalytic Action for Hydrogenation Reaction of Nitrophenol
Two-dimensional
(2D) heterostructured Ni/graphene nanocomposites
were constructed via electrostatic-induced spread by following in
situ-reduction growth process for magnetically recyclable catalysis
of <i>p</i>-nitrophenol to <i>p</i>-aminophenol.
The heterostructures with large 2D surface and moderate inflexibility
enable the superior catalytic activity and selectivity toward hydrogenation
reaction for p-nitrophenol. On the basis of high-efficiency utilization
of Ni Nps catalysis activity and electron-enhanced effect from graphene,
the coupling effect of Ni/graphene magnetic nanocomposites can lead
to highly catalytic activity for the hydrogenation reaction of p-nitrophenol
with the pseudo-first-order rate constants of 11.7 × 10<sup>–3</sup> s<sup>–1</sup>, which is over 2-fold compared to Ni Nps (5.45
× 10<sup>–3</sup> s<sup>–1</sup>) and higher than
reported noble metal nanocomposites. Complete conversion of <i>p</i>-nitrophenol was achieved with selectivity to <i>p</i>-aminophenol as high as 90% under atmosphere and room temperature.
Additionally, this heterostructured magnetic nanocatalyst can be efficiently
recycled with long lifetime and stability over 10 successive cycles.
This work displayed the value of non-noble metal/graphene nanocomposites
in catalysts development for green chemistry