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1.
Huan Jing Ke Xue ; 40(9): 3942-3948, 2019 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854856

RESUMO

In this study, 23 typical printing enterprises were selected in Beijing-Tianjin-Hebei. Through gas chromatography-mass spectrometry/flame ionization detection (GC-MS/FID), 46 sets of analysis results were obtained to quantitatively analyze the emissions characteristics of volatile organic compounds (VOCs) and the ozone generation potential of these printing enterprises. The results show that the emission concentrations of total VOCs (TVOCs) in exhaust funnels of the printing enterprises varied greatly, ranging from 3.3 mg·m-3 to 755.0 mg·m-3. In the printing stations of printing enterprises, the emission concentrations of VOCs were 129.7-958.4 mg·m-3 and 19.1-113.7 mg·m-3 in packaging and printing enterprises and publications printing enterprises, respectively. The concentration of VOCs emitted by packaging and printing enterprises was significantly higher than that of publications printing enterprises, which is related to the use of solvent-based inks. In terms of VOC composition, oxygen-containing VOCs were the primary type of those emitted by the printing station of packaging and printing enterprises and publications printing enterprises, which accounted for a ratio of 32.6%-99.4%, followed by alkanes. In terms of ozone generation potential, the average of ozone formation potential (OFP) of the printing enterprises was 505.5 mg·m-3, in which the packaging and printing enterprises was 564.1 mg·m-3, and the publication printing enterprises was 52.9 mg·m-3. The average VOC source reactivity (SR) emitted from the printing process was 1.24 g·g-1; that is, 1.24 g of O3 was formed owing to the unit mass of VOC emission, of which the packaging and printing enterprises was 1.70 g·g-1, and the publication printing enterprises was 0.89 g·g-1. According to the OFP and SR, the use of environmentally friendly ink can reduce the generation of O3 and promote air quality improvement.

2.
Nature ; 575(7782): 336-340, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31723273

RESUMO

Organoboron reagents are important synthetic intermediates that have a key role in the construction of natural products, pharmaceuticals and organic materials1. The discovery of simpler, milder and more efficient approaches to organoborons can open additional routes to diverse substances2-5. Here we show a general method for the directed C-H borylation of arenes and heteroarenes without the use of metal catalysts. C7- and C4-borylated indoles are produced by a mild approach that is compatible with a broad range of functional groups. The mechanism, which is established by density functional theory calculations, involves BBr3 acting as both a reagent and a catalyst. The potential utility of this strategy is highlighted by the downstream transformation of the formed boron species into natural products and drug scaffolds.


Assuntos
Compostos de Boro/química , Compostos de Boro/síntese química , Boro/química , Produtos Biológicos/síntese química , Produtos Biológicos/química , Teoria da Densidade Funcional , Descoberta de Drogas , Indóis/química , Compostos Organometálicos/química , Preparações Farmacêuticas/síntese química , Preparações Farmacêuticas/química
3.
Nature ; 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31569198

RESUMO

Organoboron reagents are important synthetic intermediates that play a key role in the construction of natural products, pharmaceuticals, and organic materials.1 The discovery of simpler, milder and more efficient approaches to organoborons opens a route to diverse substances.2-5 Here we show a general method of directed C-H activation for site-selective C-H borylation of arenes and heteroarenes avoiding the use of metal catalysts. C7 and C4-borylated indoles are produced by a mild approach with broad functional group compatibility. The mechanism involves BBr3 as both reagent and catalyst and is established with DFT calculations. Downstream transformation of the formed boron species to natural products and drug scaffolds highlights the potential utility of this strategy.

4.
J Org Chem ; 84(16): 10145-10159, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31313585

RESUMO

A practical single-electron-transfer-induced selective C(sp3)-N coupling of cycloketoximes with anilines via C-C bond cleavage under copper-catalytic and synergetic photoredox/copper-catalytic reaction systems has been uncovered. These two powerful and simple protocols demonstrated excellent selectivity and good functional group compatibility without any base or ligand control. Preliminary mechanistic experiments indicated that a radical-mediated process was involved in these transformations.

5.
Radiol Case Rep ; 14(8): 1047-1051, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31244963

RESUMO

Granular cell tumor (GCT) is a rare soft tissue neoplasm. At present, there is limited information available on the incidence, diagnosis, and treatment of GCTs. Therefore, we perform magnetic resonance imaging (MRI) of a perianal GCT case and review the literature of other reported cases to obtain a more comprehensive understanding of the disease. Here, we describe a rare case of perianal GCT in a 53-year-old female who presented with recurrent abdominal pain. Contrast-enhanced MRI demonstrated a well-defined perianal GCT mass, and the diagnosis was confirmed by immunostaining after mass excision. During a 10-month follow-up, there had been no evidence of recurrence. In addition, we discussed the findings of other perianal GCT cases, with regard to their age, gender, MRI analysis results, pathologic features, and treatment outcomes.

6.
J Headache Pain ; 20(1): 25, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30841847

RESUMO

OBJECTIVES: The transient receptor potential ankyrin A 1 (TRPA1) channel and calcitonin gene-related peptide (CGRP) are targets for migraine prophylaxis. This study aimed to understand their mechanisms in migraine by investigating the role of TRPA1 in cortical spreading depression (CSD) in vivo and exploring how reactive oxygen species (ROS)/TRPA1/CGRP interplay in regulating cortical susceptibility to CSD. METHODS: Immunohistochemistry was used for detecting TRPA1 expression. CSD was induced by K+ on the cerebral cortex, monitored using electrophysiology in rats, and intrinsic optical imaging in mouse brain slices, respectively. Drugs were perfused into contralateral ventricle of rats. Lipid peroxidation (malondialdehyde, MDA) analysis was used for indicating ROS level. RESULTS: TRPA1 was expressed in cortical neurons and astrocytes of rats and mice. TRPA1 deactivation by an anti-TRPA1 antibody reduced cortical susceptibility to CSD in rats and decreased ipsilateral MDA level induced by CSD. In mouse brain slices, H2O2 facilitated submaximal CSD induction, which disappeared by the antioxidant, tempol and the TRPA1 antagonist, A-967079; Consistently, TRPA1 activation reversed prolonged CSD latency and reduced magnitude by the antioxidant. Further, blockade of CGRP prolonged CSD latency, which was reversed by H2O2 and the TRPA1 agonist, allyl-isothiocyanate, respectively. CONCLUSIONS: ROS/TRPA1/CGRP signaling plays a critical role in regulating cortical susceptibility to CSD. Inhibition ROS and deactivation of TRPA1 channels may have therapeutic benefits in preventing stress-triggered migraine via CGRP.


Assuntos
Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Córtex Cerebral/metabolismo , Depressão Alastrante da Atividade Elétrica Cortical/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Canal de Cátion TRPA1/metabolismo , Animais , Modelos Animais de Doenças , Peróxido de Hidrogênio/farmacologia , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transtornos de Enxaqueca/prevenção & controle , Ratos , Ratos Sprague-Dawley , Transdução de Sinais
7.
Cephalalgia ; 39(3): 428-434, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-29695168

RESUMO

PREMISE: Migraine is a complex neurologic disorder that leads to significant disability, yet remains poorly understood. PROBLEM: One potential triggering mechanism in migraine with aura is cortical spreading depression, which can activate the trigeminal nociceptive system both peripherally and centrally in animal models. A primary neuropeptide of the trigeminal system is calcitonin gene-related peptide, which is a potent vasodilatory peptide and is currently a major therapeutic target for migraine treatment. Despite the importance of both cortical spreading depression and calcitonin gene-related peptide in migraine, the relationship between these two players has been relatively unexplored. However, recent data suggest several potential vascular and neural connections between calcitonin gene-related peptide and cortical spreading depression. CONCLUSION: This review will outline calcitonin gene-related peptide-cortical spreading depression connections and propose a model in which cortical spreading depression and calcitonin gene-related peptide act at the intersection of the vasculature and cortical neurons, and thus contribute to migraine pathophysiology.

8.
Chemosphere ; 218: 527-533, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30500713

RESUMO

Methylmercury (MeHg) can accumulate in rice and this has been demonstrated to be an important human MeHg exposure pathway. How to reduce MeHg concentrations in rice grains has therefore become a very important public health issue. Previous studies have investigated the role of plant biochars on Hg bioavailability in soils but knowledge of the influence of sewage sludge biochars (SSB) on MeHg formation and bioaccumulation in different soils is lacking. In the present study, SSB was applied to two Hg-contaminated soils, one acid and the other calcareous, in an attempt to stabilize MeHg in the soil and further mitigate MeHg accumulation in rice grains. The results indicate that the presence of SSB may promote Hg methylation in an acid soil. Moreover, MeHg concentrations increased gradually during rice growth, perhaps due to the release of root exudates. SSB can inhibit both MeHg and total Hg (THg) accumulation in different rice tissues. Both MeHg and THg decreased in the rice grains by up to 73.4 and 81.9%, respectively. However, the inhibitory effect was less pronounced in a calcareous soil. This study further demonstrates that biochar application can inhibit MeHg accumulation in soils despite the promotion of MeHg formation in soil by SSB application. However, an effect of biochar on MeHg accumulation was observed only in the acid soil. These results are useful in managing applications of biochars to Hg-contaminated paddy fields.


Assuntos
Carvão Vegetal/química , Mercúrio/farmacocinética , Compostos de Metilmercúrio/química , Oryza/química , Poluentes do Solo/química , Disponibilidade Biológica , Humanos , Concentração de Íons de Hidrogênio , Mercúrio/química , Metilação , Compostos de Metilmercúrio/farmacocinética , Oryza/metabolismo , Esgotos , Solo/química
9.
Cephalalgia ; 39(3): 333-341, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-27919019

RESUMO

OBJECTIVE: The neuropeptide calcitonin gene-related peptide (CGRP) has now been established as a key player in migraine. However, the mechanisms underlying the reported elevation of CGRP in the serum and cerebrospinal fluid of some migraineurs are not known. A candidate mechanism is cortical spreading depression (CSD), which is associated with migraine with aura and traumatic brain injury. The aim of this study was to investigate whether CGRP gene expression may be induced by experimental CSD in the rat cerebral cortex. METHODS: CSD was induced by topical application of KCl and monitored using electrophysiological methods. Quantitative PCR and ELISA were used to measure CGRP mRNA and peptide levels in discrete ipsilateral and contralateral cortical regions of the rat brain 24 hours following CSD events and compared with sham treatments. RESULTS: The data show that multiple, but not single, CSD events significantly increase CGRP mRNA levels at 24 hours post-CSD in the ipsilateral rat cerebral cortex. Increased CGRP was observed in the ipsilateral frontal, motor, somatosensory, and visual cortices, but not the cingulate cortex, or contralateral cortices. CSD also induced CGRP peptide expression in the ipsilateral, but not contralateral, cortex. CONCLUSIONS: Repeated CSD provides a mechanism for prolonged elevation of CGRP in the cerebral cortex, which may contribute to migraine and post-traumatic headache.

10.
Angew Chem Int Ed Engl ; 58(5): 1504-1508, 2019 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-30520246

RESUMO

Rhodium-catalyzed C7-selective decarbonylative arylation, olefination, and methylation of indoles with carboxylic acids or anhydrides by C-H and C-C bond activation have been developed. Furthermore, C7-acylation products can also be generated selectively at a lower reaction temperature in the developed system. The key to the high reactivity and regioselectivity of this transformation is the appropriate choice of an indole N-PtBu2 chelation-assisted group. This method has many advantages, including easy access and removal of the directing group, the use of cheap and widely available coupling agents, no requirement of an external ligand or oxidant, a broad substrate scope, high efficiency, and the formation of a sole regioisomer.

11.
Genes (Basel) ; 11(1)2019 12 31.
Artigo em Inglês | MEDLINE | ID: mdl-31906074

RESUMO

Abstract: Litsea cubeba (Lour.) Pers., a popular essential oil plant, is a dioecious species with degenerative sexual organs in both male and female individuals. Yet, the mechanism of degenerative organs development in male and female flowers is poorly understood. Here, we analyzed the morphological characters of degenerative organ development by morphological and histological observations, and determined the critical stage of abortion that occurs at pre-meiosis in male and female flowers. We also conducted RNA sequencing (RNA-seq) to understand the genetic basis of stamen abortion in female flowers. The differentially expressed genes (DEGs) were identified during the staminode development in female flowers; functional enrichment analysis revealed some important biological pathways involved the regulation of stamen abortion, including plant hormone signal transduction, phenylpropanoid biosynthesis, flavonoid biosynthesis and monoterpenoid biosynthesis. Furthermore, 15 DEGs involved in the hormone pathways were found to regulate stamen development. By HPLC-MS/MS analysis, there were a salicylic acid (SA) content peak and the gibberellin (GA) content lowest point in the abortion processes in female flowers, suggesting a vital function of hormonal processes. Co-expression network analysis further identified several hub genes that potentially played significant roles in the stamen abortion of L. cubeba. Taken together, we proposed a model involved in plant hormones pathways underlying stamen abortion during pre-meiosis in female flowers of L. cubeba.

12.
Waste Manag ; 79: 232-239, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30343751

RESUMO

The effect of phosphoric acid addition to the feed-water on the speciation and transformation behaviour of potentially toxic elements (PTEs) in the hydrothermal carbonisation (HTC) of sewage sludge was explored. Over 70% of each of the PTEs (As, Cd, Cr, Cu, Mn, Ni, Pb and Zn) was in the directly bioavailable and potentially bioavailable fraction in the raw sludge, and especially Cu and Zn at 97.5 and 98.6%, respectively. Through the HTC process the directly bioavailable and potentially bioavailable fractions of PTEs in the sludge hydrochar clearly decreased, and the residual fraction in the hydrochar showed an observable increase. Further stabilisation of PTEs in hydrochar occurred during HTC with the addition of phosphoric acid solution to the feed-water. As the concentration of phosphoric acid in the feed-water increased the percentages of the residual fraction of Cd, Cr, Ni, Pb and Zn in hydrochars each exceeded 80%, but different PTEs behaved differently with increasing phosphate molar ratio in the feed-water. When the molar ratio of phosphate was 15%, the percentages of the residual fractions of Cd, Mn and Zn reached their maximum values in accordance with the changing trend in aromaticity of the hydrochar. Moreover, a large number of phosphate mineral crystals effectively occluded the PTEs in hydrochar. In conclusion, the addition of phosphoric acid to the feed-water during HTC further deactivated PTEs leading to a substantial decline in the potential environmental risk associated with the land application of the sewage sludge.


Assuntos
Metais Pesados , Esgotos , Disponibilidade Biológica , Ácidos Fosfóricos , Água
13.
Front Neurol ; 9: 674, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30177906

RESUMO

Background: Palmitoyl ethanol amide (PEA) is an endogenously produced substance showing anti-nociceptive effect through both receptor and non-receptor mediated effects at the level of different cellular and tissue sites. This study showed the results of a single blind study that was conducted to evaluate both the safety and the efficacy of ultramicronized PEA (umPEA; 1,200 mg/day) for up 90 days in patients suffering of Migraine with Aura (MA) treated with NSAIDs. Methods: A total of 20 patients, 8 male (33-56-years, average 41.4 ± 7.8) and 12 female (19-61-years, average 38.5 ± 11.9) with MA were admitted to our observation and diagnosed according to ICHD-3 criteria, they received umPEA (1,200 mg/day) in combination with NSAIDs for up to 90 days. They were revaluated at 30, 60, and 90 days after treatment. Results: umPEA administration induced a statistically significant and time dependent pain relief. In particular, these effects were evident at 60 days (male P = 0.01189; female P = <0.01) and they lasted until the end of the study (male P = 0.0066; female P = 0.01473). Conclusion: Although further studies are needed, our findings indicate that in patients suffering of MA treatment with umPEA had good efficacy and safety which candidate this compound as a therapeutic tool in pain migraine management.

14.
J Am Chem Soc ; 140(29): 9061-9065, 2018 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-29989802

RESUMO

A copper-catalyzed system has been introduced for the enantioselective defluoroalkylation of linear 1-(trifluoromethyl)alkenes through C-F activation to synthesize various gem-difluoroalkenes as carbonyl mimics. For the first time, arylboronate-activated alkyl Grignard reagents were uncovered in this cross-coupling reaction. Mechanistic studies confirmed that the tetraorganoborate complexes generated in situ were the key reactive species for this transformation.

15.
Neuroscience ; 382: 23-34, 2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29719223

RESUMO

The transient receptor potential ankyrin type-1 (TRPA1) channels have been proposed as a potential target for migraine therapy. Yet the role of cortical TRPA1 channels in migraine mechanism has not been fully understood. Cortical spreading depression (CSD) is known as an underlying cause of migraine aura. The aim of this study is to investigate if cortical TRPA1 activity is required for CSD genesis and propagation. A mouse brain slice CSD model with intrinsic optical imaging was applied for TRPA1 signaling pharmacology. The results showed that the TRPA1 agonist, umbellulone, facilitated the propagation of submaximal CSD. Correspondingly, an anti-TRPA1 antibody and two selective TRPA1 antagonists, A967079 and HC-030031, prolonged the CSD latency and reduced magnitude, indicating a reduced cortical susceptibility to CSD under TRPA1 deactivation. Furthermore, the TRPA1 agonist, allyl-isothiocyanate (AITC), reversed the suppression of CSD by HC-030031, but not by A967079. Interestingly, the inhibitory action of A967079 on CSD was reversed by exogenous calcitonin-gene-related peptide (CGRP). Consistent to TRPA1 deactivation, the prolonged CSD latency was observed by an anti-CGRP antibody in the mouse brain slice, which was reversed by exogenous CGRP. We conclude that cortical TRPA1 is critical in regulating cortical susceptibility to CSD, which involves CGRP. The data strongly suggest that deactivation of TRPA1 channels and blockade of CGRP would have therapeutic benefits in preventing migraine with aura.


Assuntos
Depressão Alastrante da Atividade Elétrica Cortical/fisiologia , Canal de Cátion TRPA1/metabolismo , Animais , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Enxaqueca com Aura/metabolismo , Enxaqueca com Aura/fisiopatologia , Técnicas de Cultura de Órgãos
16.
Cephalalgia ; 38(11): 1748-1758, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29239212

RESUMO

Objectives Sarcoma family kinase activity is associated with multiple diseases including ischemia and cancer; however, its role in the mechanism of migraine aura has been less well characterised. This study aims to investigate whether sarcoma family kinase is required for cortical spreading depression. Methods Cortical spreading depression was induced by topical application of K+ to the cerebral cortex and was monitored using electrophysiology in rats, and intrinsic optical signal in mouse brain slices. Drugs were perfused into the contralateral cerebral ventricle for pharmacological manipulations in rats. Western blot analysis was used for detecting the level of phosphorylated, and total, sarcoma family kinase in the ipsilateral cortex of rats. Key results The data demonstrate that a single cortical spreading depression in rats induced ipsilateral cortical sarcoma family kinase phosphorylation at the Y416 site. Deactivation of sarcoma family kinase by its inhibitor (3-(4-chlorophenyl) 1-(1,1-dimethylethyl)-1 H-pyrazolo[3,4- dpyrimidin-4-amine) suppressed the elevated enzyme activity and cortical susceptibility to cortical spreading depression. Interestingly, the inhibitory effect of the N-methyl-D-aspartate receptor antagonist NVP-AAM077 on cortical spreading depression was reversed by the sarcoma family kinase activator pYEEI (EPQY(PO3H2)EEEIPIYL), suggesting a link between this enzyme and N-methyl-D-aspartate receptors. Similarly, after deactivation of sarcoma family kinase, a reduction of sarcoma family kinase phosphorylation and cortical susceptibility to cortical spreading depression was observed with NVP-AAM077. Conclusions We conclude that activation of sarcoma family kinase is required for cortical spreading depression, and this process is regulated by recruiting N-methyl-D-aspartate receptors. This study provides novel insight for sarcoma family kinase function in the mechanism of migraine aura.


Assuntos
Encéfalo/fisiologia , Depressão Alastrante da Atividade Elétrica Cortical/fisiologia , Quinases da Família src/metabolismo , Animais , Masculino , Camundongos , Enxaqueca com Aura/metabolismo , Enxaqueca com Aura/fisiopatologia , Ratos , Ratos Sprague-Dawley
17.
FASEB J ; 31(10): 4447-4457, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28687608

RESUMO

Thioredoxin reductase (TR) can help pathogens resist oxidative-burst injury from host immune cells by maintaining a thioredoxin-reduction state during NADPH consumption. TR is a necessary virulence factor that enables the persistent infection of some parasites. We performed bioinformatics analyses and biochemical assays to characterize the activity, subcellular localization, and genetic ablation of Toxoplasma gondii TR (TgTR), to shed light on its biologic function. We expressed the TgTR protein with an Escherichia coli expression system and analyzed its enzyme activity, reporting a Km for the recombinant TgTR of 11.47-15.57 µM, using NADPH as a substrate, and 130.48-151.09 µM with dithio-bis-nitrobenzoic acid as a substrate. The TgTR sequence shared homology with that of TR, but lacked a selenocysteine residue in the C-terminal region and was thought to contain 2 flavin adenine dinucleotide (FAD) domains and 1 NADPH domain. In addition, immunoelectron microscopy results showed that TgTR was widely dispersed in the cytoplasm, and we observed that parasite antioxidant capacity, invasion efficiency, and proliferation were decreased in TR-knockout (TR-KO) strains in vitro, although this strain still stimulated the release of reactive oxygen species release in mouse macrophages while being more sensitive to H2O2 toxicity in vitro Furthermore, our in vivo results revealed that the survival time of mice infected with the TR-KO strain was significantly prolonged relative to that of mice infected with the wild-type strain. These results suggest that TgTR plays an important role in resistance to oxidative damage and can be considered a virulence factor associated with T. gondii infection.-Xue, J., Jiang, W., Chen, Y., Gong, F., Wang, M., Zeng, P., Xia, C., Wang, Q., Huang, K. Thioredoxin reductase from Toxoplasma gondii: an essential virulence effector with antioxidant function.


Assuntos
Antioxidantes/farmacologia , Tiorredoxina Dissulfeto Redutase/metabolismo , Tiorredoxinas/metabolismo , Toxoplasma/enzimologia , Animais , Escherichia coli/metabolismo , Feminino , Peróxido de Hidrogênio/farmacologia , Camundongos , NADP/metabolismo , Toxoplasma/efeitos dos fármacos , Toxoplasma/genética , Toxoplasma/patogenicidade , Virulência/efeitos dos fármacos , Fatores de Virulência/metabolismo
18.
Nat Commun ; 8: 14993, 2017 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-28474671

RESUMO

Amide and olefins are important synthetic intermediates with complementary reactivity which play a key role in the construction of natural products, pharmaceuticals and manmade materials. Converting the normally highly stable aliphatic amides into olefins directly is a challenging task. Here we show that a Ni/NHC-catalytic system has been established for decarbonylative elimination of aliphatic amides to generate various olefins via C-N and C-C bond cleavage. This study not only overcomes the acyl C-N bond activation in aliphatic amides, but also encompasses distinct chemical advances on a new type of elimination reaction called retro-hydroamidocarbonylation. This transformation shows good functional group compatibility and can serve as a powerful synthetic tool for late-stage olefination of amide groups in complex compounds.

19.
Angew Chem Int Ed Engl ; 56(25): 7233-7237, 2017 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-28504845

RESUMO

Modification of commercially available monophosphine ligands with either aryl bromides or chlorides by rhodium(I)-catalyzed, tertiary phosphine directed C-H activation is described. A series of ligand libraries containing mono- and diaryl-substituted groups, having different steric and electronic properties, were obtained in high yields. Based on the outstanding properties of their parent scaffolds, the modified ligands have been found to be powerful in organic reactions.

20.
Bioresour Technol ; 228: 218-226, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28064134

RESUMO

A novel type of biochar was produced by mixing bamboo sawdust with sewage sludge (1:1, w/w) via a co-pyrolysis process at 400-600°C. Changes in physico-chemical properties and the intrinsic speciation of metals were investigated before and after pyrolysis. Co-pyrolysis resulted in a lower biochar yield but a higher C content in the end product compared with use of sludge alone as the raw material. FT-IR analysis indicates that phosphine derivatives containing PH bonds were formed in the co-pyrolyzed biochars. In addition, co-pyrolysis of sludge with bamboo sawdust transformed the potentially toxic metals in the sludge into more stable fractions, leading to a considerable decrease in their direct toxicity and bioavailability in the co-pyrolyzed biochar. In conclusion, the co-pyrolysis technology provides a feasible method for the safe disposal of metal-contaminated sewage sludge in an attempt to minimize the environmental risk from potentially toxic metals after land application.


Assuntos
Carvão Vegetal/síntese química , Metais Pesados/química , Esgotos/química , Eliminação de Resíduos Líquidos/métodos , Madeira/química , Carvão Vegetal/química , Espectroscopia de Infravermelho com Transformada de Fourier
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