49 research outputs found
Reactions of Amine and Peroxynitrite: Evidence for Hydroxylation as Predominant Reaction and New Insight into the Modulation of CO<sub>2</sub>
Peroxynitrite is related to numerous diseases including
cardiovascular
diseases, inflammation, and cancer. In order to expand the understanding
for the toxicology of peroxynitrite in biological system, the reactions
of amine (morpholine as a probe) with peroxynitrite and the modulation
of CO<sub>2</sub> were investigated by using DFT methods. The results
strongly indicate that the hydroxylation of amine by peroxynitrous
acid ONOOH, which was previously overlooked by most studies, is predominant
relative to the widely reported nitration and nitrosation in the absence
of CO<sub>2</sub>. The product <i>N</i>-hydroxylamine is
proposed to be mainly generated via nonradical pathway (two-electron
oxidation). The modulation of CO<sub>2</sub> exhibits two main functions:
(1) inhibition of hydroxylation due to the promoted consumption of
peroxynitrite via fast reaction of CO<sub>2</sub> with ONOOÂŻ
to form ONOOCO<sub>2</sub>ÂŻ; (2) dual effect (catalysis and inhibition)
of CO<sub>2</sub> toward nitration and nitrosation. As a new insight,
amine does react with CO<sub>2</sub> and produce inert amine carbamate
R<sub>2</sub>NCOOÂŻ. This reaction has the potential to compete
with the reaction of CO<sub>2</sub> and ONOOÂŻ, which leads to
inhibition of nitration and nitrosation. The concentration of CO<sub>2</sub> could be a critical factor determining the final effect,
catalysis or inhibition. As a new finding, HCO<sub>3</sub>ÂŻ is
probably an effective catalyst for the reaction of amine and CO<sub>2</sub>. Moreover, further studies on how the different types of
the amine might affect the outcome of the reactions would be an interesting
topic
High-Performance Recovery of Vanadium(V) in Leaching/Aqueous Solution by a Reusable Reagent-Primary Amine N1519
Efficient
extraction and stripping for recovering vanadiumÂ(V) from
the leaching/aqueous solution of chromium-bearing vanadium slag (VâCr
slag) are essential to the reuse of heavy metals. The performance
characteristics of a new reagent, primary amine N1519, were first
reported for extracting vanadium. With a phase ratio of organic to
aqueous up to 1:1, 99.7% of vanadiumÂ(V) can be effectively extracted
from the leaching/aqueous solution, and powder of NH<sub>4</sub>VO<sub>3</sub> was obtained through the stripping with ammonia. The new
reagent can be recyclable in use for sustainable reuse after stripping.
Different extraction conditions, e.g., the initial pH of the leaching/aqueous
solution and the molar quantity of N1519 were investigated. The powder
of vanadium-organic compounds (VOC) with N1519 formed in the process
of extraction was obtained and purified through three-steps of solvent-out
crystallizations. The hydrogen bond association mechanism of extraction
was illustrated with the structure of VOC and the enthalpy change
in extraction process. The fast extraction process and slow stripping
procedure for recovering vanadiumÂ(V) are suitable for use in annular
centrifugal contactors with very short contact/resident times and
mixed-settler extractors with very good mass transfer, respectively.
The results offer significant advantages over conventional processes
Data_Sheet_1_Growth of Stipa breviflora does not respond to nitrogen addition because of its conservative nitrogen utilization.docx
Enhanced atmospheric nitrogen (N) deposition is threating species diversity in the desert steppe ecoregions. Needlegrass (Stipa breviflora) is the dominant specie in the desert steppe grasslands of China and southern Mongolia, and the response of S. brevifolia to N deposition is not well known. In this study, we conducted an experiment to determine the growth and N uptake of S. breviflora in response to several N addition rates. The results showed that N addition did not change plant growth, emergence rate, plant height, or biomass of S. breviflora, even at a N addition rate of 50âkgâNâhaâ1 yr.â1 with sufficient soil moisture during a 120-day growth period. The absence of a N effect was due to the fact that N uptake in S. breviflora was not improved by N addition. These results indicated that S. breviflora is very conservative with respect to N utilization, which could possibly help it resist enhanced atmospheric N deposition. Moreover, conservative N utilization also enables S. breviflora to survive in N-limiting soils.</p
A Cleaner Process for Selective Recovery of Valuable Metals from Electronic Waste of Complex Mixtures of End-of-Life Electronic Products
In
recent years, recovery of metals from electronic waste within
the European Union has become increasingly important due to potential
supply risk of strategic raw material and environmental concerns.
Electronic waste, especially a mixture of end-of-life electronic products
from a variety of sources, is of inherently high complexity in composition,
phase, and physiochemical properties. In this research, a closed-loop
hydrometallurgical process was developed to recover valuable metals,
i.e., copper and precious metals, from an industrially processed information
and communication technology waste. A two-stage leaching design of
this process was adopted in order to selectively extract copper and
enrich precious metals. It was found that the recovery efficiency
and extraction selectivity of copper both reached more than 95% by
using ammonia-based leaching solutions. A new electrodeposition process
has been proven feasible with 90% current efficiency during copper
recovery, and the copper purity can reach 99.8 wt %. The residue from
the first-stage leaching was screened into coarse and fine fractions.
The coarse fraction was returned to be releached for further copper
recovery. The fine fraction was treated in the second-stage leaching
using sulfuric acid to further concentrate precious metals, which
could achieve a 100% increase in their concentrations in the residue
with negligible loss into the leaching solution. By a combination
of different leaching steps and proper physical separation of light
materials, this process can achieve closed-loop recycling of the waste
with significant efficiency
The Hydrogen Abstraction Reaction H<sub>2</sub>S + OH â H<sub>2</sub>O + SH: Convergent Quantum Mechanical Predictions
The hydrogen abstraction
reaction H<sub>2</sub>S + OH â
H<sub>2</sub>O + SH has been studied using the âgold standardâ
CCSDÂ(T) method along with the Dunningâs aug-cc-pVXZ (up to
5Z) basis sets. For the reactant (entrance) complex, the CCSDÂ(T) method
predicts a HSH···OH hydrogen-bonded structure to be
lowest-lying, and the other lower-lying isomers, including the two-center
three-electron hemibonded structure H<sub>2</sub>S···OH,
have energies within 2 kcal/mol. The similar situation is for the
product (exit) complex. With the aug-cc-pV5Z single point energies
at the aug-cc-pVQZ geometry, the dissociation energy for the reactant
complex to the reactants (H<sub>2</sub>S + OH) is predicted to be
3.37 kcal/mol, and that for the product complex to the products (H<sub>2</sub>O + SH) is 2.92 kcal/mol. At the same level of theory, the
classical barrier height is predicted to be only 0.11 kcal/mol. Thus,
the OH radical will react promptly with H<sub>2</sub>S in the atmosphere.
We have also tested the performance of 29 density functional theory
(DFT) methods for this reaction. Most of them can reasonably predict
the reaction energy, but the different functional give quite different
energy barriers, ranged from â10.3 to +2.8 kcal/mol, suggesting
some caution in choosing density functionals to explore the PES of
chemical reactions
The PeptideAtlas of the Domestic Laying Hen
Proteomics-based biological research
is greatly expanded by high-quality
mass spectrometry studies, which are themselves enabled by access
to quality mass spectrometry resources, such as high-quality curated
proteome data repositories. We present a PeptideAtlas for the domestic
chicken, containing an extensive and robust collection of chicken
tissue and plasma samples with substantial value for the chicken proteomics
community for protein validation and design of downstream targeted
proteome quantitation. The chicken PeptideAtlas contains 6646 canonical
proteins at a protein FDR of 1.3%, derived from âŒ100âŻ000
peptides at a peptide level FDR of 0.1%. The rich collection of readily
accessible data is easily mined for the purposes of data validation
and experimental planning, particularly in the realm of developing
proteome quantitation workflows. Herein we demonstrate the use of
the atlas to mine information on common chicken acute-phase proteins
and biomarkers for cancer detection research, as well as their localization
and polymorphisms. This wealth of information will support future
proteome-based research using this highly important agricultural organism
in pursuit of both chicken and human health outcomes
Sustainable Preparation of LiNi<sub>1/3</sub>Co<sub>1/3</sub>Mn<sub>1/3</sub>O<sub>2</sub>âV<sub>2</sub>O<sub>5</sub> Cathode Materials by Recycling Waste Materials of Spent Lithium-Ion Battery and Vanadium-Bearing Slag
Waste
streams containing heavy metals are always of concern from
both environmental and resource-depleting points of view. The challenges
are in most cases related to the effectiveness for high-value-added
materials recovery from such waste, with which the environmental impacts
during recycling shall be low. In this research, two typical heavy-metal-containing
waste streams, i.e., spent lithium-ion batteries and vanadium-bearing
slag, were simultaneously treated, and this enables regeneration of
the LiNi<sub>1/3</sub>Co<sub>1/3</sub>Mn<sub>1/3</sub>O<sub>2</sub> cathode materials which was considered difficult because of the
dislocation of nickel and lithium ions during electrochemical performance.
By using the intermediate product during vanadium-bearing slag treatment,
the vanadium-embedded cathode material can be prepared which delivers
excellent electrochemical performances with a specific capacity of
156.3 mA h g<sup>â1</sup> after 100 cycles at 0.1C with the
capacity retention of 90.6%; even the additive amount is only 5%.
A thin layer of vanadium oxide is found to be effective to promote
electrochemical performance of the cathode material. Using the principles
of green chemistry, this process enables high-performance cathode
material regeneration without introducing extraction chemicals and
with much lower environmental impacts as compared to traditional metallurgical
technologies
Lithium Carbonate Recovery from Cathode Scrap of Spent Lithium-Ion Battery: A Closed-Loop Process
A closed-loop
process to recover lithium carbonate from cathode
scrap of lithium-ion battery (LIB) is developed. Lithium could be
selectively leached into solution using formic acid while aluminum
remained as the metallic form, and most of the other metals from the
cathode scrap could be precipitated out. This phenomenon clearly demonstrates
that formic acid can be used for lithium recovery from cathode scrap,
as both leaching and separation reagent. By investigating the effects
of different parameters including temperature, formic acid concentration,
H<sub>2</sub>O<sub>2</sub> amount, and solid to liquid ratio, the
leaching rate of Li can reach 99.93% with minor Al loss into the solution.
Subsequently, the leaching kinetics was evaluated and the controlling
step as well as the apparent activation energy could be determined.
After further separation of the remaining Ni, Co, and Mn from the
leachate, Li<sub>2</sub>CO<sub>3</sub> with the purity of 99.90% could
be obtained. The final solution after lithium carbonate extraction
can be further processed for sodium formate preparation, and Ni, Co,
and Mn precipitates are ready for precursor preparation for cathode
materials. As a result, the global recovery rates of Al, Li, Ni, Co,
and Mn in this process were found to be 95.46%, 98.22%, 99.96%, 99.96%,
and 99.95% respectively, achieving effective resources recycling from
cathode scrap of spent LIB
Experimental and Theoretical Investigation of Effects of Ethanol and Acetic Acid on Carcinogenic NDMA Formation in Simulated Gastric Fluid
<i>N</i>-nitrosodimethylamine
(NDMA), as a representative
of endogenously formed N-nitroso compounds (NOCs), has become the
focus of considerable research interest due to its unusually high
carcinogenicity. In this study, effects of ethanol and acetic acid
on the formation of NDMA from dimethylamine (DMA) and nitrite in simulated
gastric fluid (SGF) were investigated. Experimental results showed
that ethanol in the concentrations of 1â8% (v/v) and acetic
acid in the concentrations of 0.01â8% (v/v) exhibit inhibitory
and promotion effects on the formation of NDMA, respectively. Moreover,
they are both in a dose-dependent manner with the largest inhibition/promotion
rate reaching âŒ70%. Further experimental investigations indicate
that ethanol and acetic acid are both able to scavenge nitrite in
SGF. It implies that there are interactions of ethanol and acetic
acid with nitrite or nitrite-related nitrosating agents rather than
DMA. Theoretical calculations confirm the above experimental results
and demonstrate that ethanol and acetic acid can both react with nitrite-related
nitrosating agents to produce ethyl nitrite (EtONO) and acetyl nitrite
(AcONO), respectively. Furthermore, the reactivities of ethyl nitrite,
acetyl nitrite, and dinitrogen trioxide reacting with DMA were found
in the order of AcONO > N<sub>2</sub>O<sub>3</sub> â« EtONO.
This is probably the main reason why there are completely different
effects of ethanol and acetic acid on NDMA formation. On the basis
of the above results, two requirements for a potential inhibitor of
NOCs formation in SGF were provided. The results obtained in this
study will be helpful in better understanding the inhibition/promotion
mechanisms of compounds on NDMA formation in SGF and searching for
protective substances to prevent carcinogenic NOCs formation
Level table of orthogonal test factors.
ObjectiveTo explore the potential mechanism of Shenkang injection (SKI) in the treatment of chronic renal failure based on network pharmacology and molecular docking technology, and to verify the core targets and key pathways by using the renal failure model.MethodsThe active components and targets of Shenkang injection were retrieved by TCMSP database, and the disease related targets were obtained by OMIM, GeneCards and other databases. Then, the intersection was obtained, and were imported into String database for PPI analysis. After further screening of core targets, GO and KEGG analysis were performed. Autodock software was used to predict the molecular docking and binding ability of the selected active ingredients and core targets. Chronic renal failure (CRF) model was established by adenine induction in rats, and the pathological observation of renal tissues was conducted. Meanwhile, the effects of Shenkang injection and its active components on core targets and pathways of renal tissues were verified.ResultsThe results of network pharmacology showed that the main components of Shenkang injection might be hydroxysafflor yellow A (HSYA)ătanshinolărheum emodinăAstragaloside IV. Through enrichment analysis of core targets, it was found that Shenkang injection may play an anti-chronic renal failure effect through PI3K-Akt signaling pathway. Molecular docking results showed that the above pharmacodynamic components had strong binding ability with the target proteins PI3K and Akt. The results of animal experiments showed that renal function indexes of Shenkang injection group and pharmacodynamic component group were significantly improved compared with model group. HE staining results showed that the pathological status of the kidney was significantly improved in SKI and pharmacodynamic component treatment groups. Immunohistochemical results showed that the renal fibrosis status was significantly reduced in SKI and pharmacodynamic component treatment groups. q-RTPCR and WB results showed that the expression levels of PI3K and Akt were significantly decreased in the treatment groups (PConclusionsShenkang injection may inhibit PI3K-Akt signaling pathway to play an anti-chronic renal failure role through the pharmacodynamic component hydroxysafflor yellow A (HSYA), tanshinol, rheum emodin, Astragaloside IV.</div