Experiment and Computational Study on Pd-Catalyzed Methoxyiminoacyl-Directed γ-Alkoxylation of Alkylamides.

The direct alkoxylation of amides has been accomplished via methoxyiminoacyl (MIA)-mediated Pd-catalyzed C-H functionalization. A diverse array of alkylamide substrates is amenable to this protocol, providing γ-C(sp3)-alkoxylation of alkylamide derivatives with good to high efficiency. Two aspects of the research were completed to explore the reaction mechanism. On the one hand, the result of the kinetic isotopic effect experiment and control experiment indicated that reductive elimination is a rate-limiting step. On the other hand, density functional theory calculations demonstrated that a concerted Sn2 reductive elimination mechanism pathway is prior. Finally, the MIA group could be efficiently hydrogenated and protected in a one-pot procedure, which provides a short synthetic route to γ-methoxy amino acid derivatives.

Metallophilic Interaction-Mediated Hierarchical Assembly and Temporal-Controlled Dynamic Chirality Inversion of Metal-Organic Supramolecular Polymers.

The study of dynamic supramolecular chirality inversion (SMCI) not only helps to deepen the understanding of chiral transfer and amplification in both living organizations and artificially chemical self-assembly systems but also is useful for the development of smart chiral nanomaterials. However, it is still challenging to achieve the dynamic SMCI of the self-aggregation of metal-organic supramolecular polymers with great potential in asymmetric synthesis, chiroptical switches, and circular polarized luminescence. Here, we successfully developed a hierarchical coassembly system based on the mPAzPCC and various metal ions with effective chirality transfer and temporal-controlled SMCI. Due to the dynamic self-assembly and hierarchical chirality transfer of the Ag+/mPAzPCC complex driven by metallophilic interaction and coordination, morphological transition with nanoribbons, helical nanoribbons, and chiral nanotubules was successively obtained. Interestingly, the SMCI of chiral nanoaggregates was precisely regulated by solvents and metal ions in the Cu2+/mPAzPCC and Mn2+/mPAzPCC system. Besides, temporal-controlled dynamic SMCI switching from helix to bundled helix was clearly revealed in the aggregation of Cu2+/mPAzPCC, Mn2+/mPAzPCC, and Bi3+/mPAzPCC systems. This work provides a metallophilic interaction-mediated helical assembly pathway to dynamically modulate the chirality of metal-organic complex-based assemblies and deepen the understanding of the hierarchically dynamic self-assembly process, which would be of great potential in metal ion-mediated supramolecular asymmetric catalysis and bioinspired chiral sensing.

Multicomponent TiO2/Ag/Cu7S4@Se Heterostructures Constructed by an Interface Engineering Strategy for Promoting the Electrocatalytic Nitrogen Reduction Reaction Performance.

The electrocatalytic nitrogen reduction reaction (ECNRR) is a sustainable and environmentally friendly method for NH3 synthesis under environmental conditions relative to the Haber-Bosch process; however, its low selectivity (Faradaic efficiency (FE)) and low NH3 yield impede the progress. Herein, benefiting from the application of the interface engineering strategy, a multicomponent TiO2/Ag/Cu7S4@Se-CC heterogeneous electrocatalyst with a unique structure was successfully fabricated, generating a unique sandwich structure by using a Ag layer as an electric bridge intercalated between TiO2 and Cu7S4, in which the optimized catalyst can accelerate the electron transfer efficiency. Moreover, through the electronic structure adjustment, an electron-deficient region was constructed, which can inhibit the H2 adsorption but enhance the N2 adsorption, thereby improving the selectivity and the catalytic activity. Significantly, the FE and NH3 yield of TiO2/Ag/Cu7S4@Se-CC reached 51.05 ± 0.16% and 39.16 ± 2.31 µg h-1 cm-2, in which the FE is among the highest non-precious metal-based NRR electrocatalysts in alkaline electrolytes reported. This study provides insight into the rational design and construction of NRR electrocatalysts for electrocatalytic applications.

Pd-Catalyzed γ-Acetoxylation of Alkylamides: Structural Influence of Directing Groups.

Although direct acetoxylation and cyclization of alkylamide have been extensively reported, investigation of the structural influence of directing groups on selectivity is limited. Pd-catalyzed 2-methoxyiminoacyl (MIA) assisted γ-acetoxylation of alkylamides has been developed. Further DFT studies have demonstrated that the directing groups have a significant influence on the reductive elimination step. The strong electron-donating effect of the OMe group in MIA leads to the preferential formation of a five-membered cyclopalladium (OAc-Pd-C) complex, which favors the acetoxylation pathway.

A new species of Polyneura Westwood, 1842 from Yunnan, China (Hemiptera, Cicadidae, Cicadinae).

Background: The tribe Polyneurini Amyot & Audinet-Serville, 1843 (Hemiptera: Cicadidae: Cicadinae) is a small tribe which includes four genera and 18 species, distributing in eastern Palaearctic and Oriental Regions. Most of them, four genera and 16 species, are known from China. New information: A remarkable new species of cicada, Polyneuraguoliangi sp. n. (Hemiptera, Cicadidae, Cicadinae), is described and illustrated from Yunnan, southwest China. The diagnostic characters of the new species are compared with allied species or genera.

Copper/silver co-mediated three-component bicyclization for accessing indeno[1,2-c]azepine-3,6-diones.

A new copper/silver-co-mediated three-component bicyclization of benzene-linked 1,6-enynes with ICF2CO2Et with TMSN3 was reported, and used to produce a wide range of hitherto unreported difluorinated tetrahydroindeno[1,2-c]azepine-3,6-diones with moderate to good yields. The mechanistic pathway consists of radical-induced 1,6-addition-cyclization, oxidative addition, reductive elimination, nitrene insertion and N-O cleavage, resulting in continuous multiple bond-forming events including C-C and C-N bonds to build up a 6/5/7 tricyclic framework.

Au(I)-Catalyzed Domino Cyclization of 1,6-Diynes Incorporated with Indole.

We disclose herein a Au(I)-catalyzed domino cyclization of 1,6-diynes incorporated with indole. This protocol enabled the diastereoselective buildup of indole-fused azabicyclo[3.3.1]nonanes from linear precursors. Density functional theory calculations showed that the reaction proceeded via an unprecedented cascade dearomatization/rearomatization/dearomatization process. Independent gradient model analysis revealed that a noncovalent attractive interaction between the distal alkyne and the Au/proximal complex was responsible for the chemoselectivity of the first spirocyclization step.

A water stable Eu(III)-organic framework as a recyclable multi-responsive luminescent sensor for efficient detection of p-aminophenol in simulated urine, and MnVII and CrVI anions in aqueous solutions.

A novel 3D Eu(iii) metal-organic framework (Eu-MOF-1) formulated as [Eu(L)(H2O)(DMA)] (L = 2-(2-nitro-4-carboxylphenyl)terephthalic acid) has been successfully synthesized under solvothermal conditions and characterized by structural analyses. Eu-MOF-1 displays a new 3D framework containing EuIII ions, ligand L, and coordinated DMA molecules and water molecules. The fluorescence investigations indicate that Eu-MOF-1 emits bright red luminescence, and shows relatively high water stability and outstanding chemical stability under a relatively wide range of pH conditions. It is noteworthy that Eu-MOF-1 can quantitatively detect p-aminophenol (PAP) which is a metabolite of phenylamine in human urine. More significantly, Eu-MOF-1 is the first reported multi-responsive luminescent sensor for detecting the biomarker PAP, and MnVII and CrVI anions with high selectivity, sensitivity, recyclability and relatively low detection limits in aqueous solutions. Furthermore, the possible sensing mechanisms of Eu-MOF-1 for selective sensing have also been explored in detail. Eu-MOF-1 could be an ideal candidate as a multi-responsive luminescent sensor in biological and environmental areas.

Single-Cell Sequencing and Organoids: A Powerful Combination for Modelling Organ Development and Diseases.

The development and function of a particular organ and the pathogenesis of various diseases remain intimately linked to the features of each cell type in the organ. Conventional messenger RNA- or protein-based methodologies often fail to elucidate the contribution of rare cell types, including some subpopulations of stem cells, short-lived progenitors and circulating tumour cells, thus hampering their applications in studies regarding organ development and diseases. The scRNA-seq technique represents a new approach for determining gene expression variability at the single-cell level. Organoids are new preclinical models that recapitulate complete or partial features of their original organ and are thought to be superior to cell models in mimicking the sophisticated spatiotemporal processes of the development and regeneration and diseases. In this review, we highlight recent advances in the field of scRNA-seq, organoids and their current applications and summarize the advantages of using a combination of scRNA-seq and organoid technology to model diseases and organ development.

MIA-Directed 2-Pyridione-Enabled Selective Ortho-C-H Arylation of Phenylalanine: A Mechanistic Study.

The 2-methoxyiminoacyl-mediated arylation of substituted phenylalanines has been examined. Selective monoarylation at the ortho position was achieved using pyridone ligands which decelerate the arylation process. Density functional theory (DFT) study of a continuous C-H arylation process that included the first and second arylation stage was performed. The computational result shows that the introduction of a pyridone ligand obviously disfavors the second arylation stage, which directly contributes to the selectivity between the mono/diarylated products. Furthermore, results of the kinetic isotope effect and a control experiment are agreed with DFT study.

Water-stable Cd(ii)/Zn(ii) coordination polymers as recyclable luminescent sensors for detecting hippuric acid in simulated urine for indexing toluene exposure with high selectivity, sensitivity and fast response.

Three novel Cd(ii)/Zn(ii) coordination polymers (CPs), namely [Cd(L)(BPDC)0.5H2O]·0.5H2O (1), [Zn2(L)2(BPDC)]·2H2O (2) and [Cd2(L)(BTC)H2O]·3H2O (3) (L = 4-(tetrazol-5-yl)phenyl-4,2':6',4''-terpyridine, H2BPDC = 4,4'-biphenyldicarboxylic acid, and H3BTC = 1,3,5-benzenetricarboxylic acid), have been successfully synthesized and characterized. CP 1 and CP 2 display new two-dimensional double-layered honeycomb frameworks containing uncoordinated nitrogen atoms from pyridine and tetrazole rings, which can easily form hydrogen bonds with various analytes. CP 3 exhibits a 3D framework also with uncoordinated nitrogen atoms from pyridine and tetrazole rings. The fluorescence explorations indicate that CPs 1-3 exhibit strong blue luminescence and excellent chemical stability under a relatively wide range of pH conditions. It is worth noting that CPs 1-3 can quantitatively detect hippuric acid (HA), which is a metabolite of toluene in human urine, with high selectivity, sensitivity, fast response and relatively low detection limits. Moreover, the sensing mechanism of CPs 1-3 for HA can mainly be ascribed to fluorescence resonance energy transfer (FRET). CPs 1-3 could be ideal candidates as HA sensors in human urine samples for practical applications. Notably, to the best of our knowledge, we report for the first time Cd(ii)/Zn(ii)-based luminescent sensors for detecting HA in simulated urine.

A review of the genus Trachystolodes Breuning, 1943 (Coleoptera: Cerambycidae: Lamiinae: Lamiini).

A taxonomic review of the genus Trachystolodes Breuning is presented. A new species, Trachystolodes huangjianbini sp. nov., is described from southeast China. Trachystolodes tonkinensis Breuning, 1943 is redescribed and its distribution is discussed. Trachystolodes is redescribed and a key to three known species of Trachystolodes is presented.

[Regional Evolution and Control Factors of Karst Groundwater in Liulin Spring Catchment].

The Liulin Spring is one of the ten most famous karst springs in the Shanxi province. The abundant karst groundwater resources support the economic and social development in the Luliang Prefecture. Therefore, the study of evolution and control factors of karst groundwater is of great significance to the sustainable utilization of water resources in the watershed. For revealing the evolution and control factors of karst groundwater in the Liulin Spring area, the main ion components of 29 karst groundwater samples from spring supply area, runoff area, discharge area, and deep buried area were analyzed. The results showed that the temperature and Na+, Ca2+, Mg2+, Cl-, HCO3-, and SO42- concentrations increased continuously along the runoff route, from the recharge area to the runoff area, to the discharge area, and then to the deep burial area. K+, Na+, and Cl- mainly come from salt rock dissolution, and Ca2+, Mg2+, HCO3-, and SO42- mainly come from the dissolution of calcite, dolomite, and gypsum. Because they are controlled by the continuous dissolution of salt rock and gypsum, the concentration of Na+, Cl-, and SO42- in groundwater has increased greatly, with the maximum value being 50 times, 80 times, and 32 times of the minimum value, respectively. Under the influence of dedolomitization, the concentration of Ca2+ and HCO3- in groundwater does not change significantly, the maximum is 2-3 times of the minimum. In the recharge area and runoff area, Na+ and Cl- amounts are lower, and Ca2+ and HCO3- are the main cations and anions in the groundwater. However, in the discharge area and deep buried area, Cl- and Na+ exceed HCO3-, Ca2+, and Mg2+ and become the main anions and cations in the groundwater. The hydrochemical type changes from HCO3-Ca·Mg in the supply area to HCO3·SO4-Ca·Mg in the runoff area, to HCO3·SO4-Ca·Na·Mg in the recharge area, and finally to Cl·HCO3-Na·Ca, Cl·HCO3-Na, and Cl-Na·Ca in the deep burial area.

[Migration and Transformation of Dissolved Organic Matter in Karst Water Systems and an Analysis of Their Influencing Factors].

Fluorescent substances are used as good tracers in dissolved organic matter (DOM) to identify the source of DOM and its geochemical behavior in a hydrological system. However, there are few studies on the karst aquifer system. Many parameters in karst systems affect the DOM spectral information. A typical karst watershed in Northern China was selected in this research. Excitation-emission matrices (EEMs), parallel factor analysis (PARAFAC), and hydrochemical data were applied to reveal the relationship between the composition and transformation of DOM fluorescent substances in different karst water-bearing spaces. The source of DOM and the effect of water chemistry on DOM transfer were also discussed. The results showed that DOM in exogenous surface water and karst surface water in the Yufu River watershed were mainly composed of tryptophan-like substances, while the DOM in shallow karst water and deep karst water consisted of tryptophan-like and tyrosine-like substances. A comprehensive analysis by fluorescence index (FI), biological index (BIX), and humification index (HIX) displayed that the DOM in shallow and deep karst water resulted from microbial decomposition. In contrast, the DOM in karst surface water and exogenous surface water resulted from land-based input and endogenous microbial decomposition, in which endogenous contributions occupy a large proportion. Due to the chemical parameters of karst water, these three kinds of fluorescent substances extracted by PARAFAC had obviously different characteristics, i.e., ① the tyrosine-like substances had a strong adaptability to Ca2+ and HCO3-, and the proportion of the tyrosine in karst water was relatively large; ② the tryptophan substance followed an opposite trend; and ③ there was a significant positive correlation between fulvic acid and TDS, turbidity, Cl-, and SO42-. Observations of the watershed runoff revealed that the DOM in shallow karst water in the upper reaches came mainly from the soil and microbial degradation. The organic matter underwent a large amount of microbial decomposition and exogenous input when the water was rejuvenated with springs. After infiltration to the deep karst water in the lower reaches, the DOM gradually were converted to low aromatic hydrocarbon organic compounds and decreased macromolecules of DOM. Subsequently, the fluorescence intensity was weakened. The principal component analysis (PCA) extracted three principal components. They were the water mineralization index, soil leaching index, and hydrochemical/biochemical process index. The water mineralization index consists of hydrochemical parameters reflecting the water infiltration, transformation, and flow conditions in the karst system. The soil leaching index contains TOC, NO3-, and protein-like indicators relating to the relationship between protein-like substances and soil and natural leaching. The hydrochemical/biochemical process index is composed of Ca2+, HCO3-, FI, and fulvic acid indicators that illustrate the water chemistry and biochemical processes in the karst water system. In addition, the study also showed that total fluorescence intensity, fulvate-like substances, and protein-like substances can be used as a tracer for rapid seepage, transformation, and aquifer fragility for karst water, respectively. The results of the study are important in understanding the biogeochemical cycle of DOM in the karst water system and also helpful for controlling organic pollution. It also provides a new tool for characterizing the geochemical processes of organic matter in karst system.

Metal-Free Aerobic Oxidative Cyanation of Tertiary Amines: Azobis(isobutyronitrile) (AIBN) as a Sole Cyanide Source.

An aerobic oxidative cyanation for the synthesis of α-aminonitriles was reported. The formation of C(sp3)-CN bonds was achieved under a metal-free condition by utilizing azobis(isobutyronitrile) as a sole organic cyanide source with the combination of pivalic acid and sodium acetate as additives.

Impact of sulfuric and nitric acids on carbonate dissolution, and the associated deficit of CO2 uptake in the upper-middle reaches of the Wujiang River, China.

Carbonate weathering and the CO2 consumption in karstic area are extensive affected by anthropogenic activities, especially sulfuric and nitric acids usage in the upper-middle reaches of Wujiang River, China. The carbonic acid would be substituted by protons from sulfuric and nitric acids which can be reduce CO2 absorption. Therefore, The goal of this study was to highlight the impacts of sulfuric and nitric acids on carbonate dissolution and the associated deficit of CO2 uptaking during carbonate weathering. The hydrochemistries and carbon isotopic signatures of dissolved inorganic carbon from groundwater were measured during the rainy season (July; 41 samples) and post-rainy season (October; 26 samples). Our results show that Ca2+ and Mg2+ were the dominant cations (55.87-98.52%), and HCO3- was the dominant anion (63.63-92.87%). The combined concentrations of Ca2+ and Mg2+ commonly exceeded the equivalent concentration of HCO3-, with calculated [Ca2++Mg2+]/[HCO3-] equivalent ratios of 1.09-2.12. The mean measured groundwater δ13CDIC value (-11.38‰) was higher than that expected for carbonate dissolution mediated solely by carbonic acid (-11.5‰), and the strong positive correlation of these values with [SO42-+NO3-]/HCO3- showed that additional SO42- and NO3- were required to compensate for this cation excess. Nitric and sulfuric acids are, therefore, suggested to have acted as the additional proton-promoted weathering agents of carbonate in the region, alongside carbonic acid. The mean contribution of atmospheric/pedospheric CO2 to the total aquatic HCO3- decreased by 15.67% (rainy season) and 14.17% (post-rainy season) due to the contributions made by these acids. The annual mean deficit of soil CO2 uptake by carbonate weathering across the study area was 14.92%, which suggests that previous workers may have overestimated the absorption of CO2 by carbonate weathering in other karstic areas worldwide.

[Major Ionic Features and Their Controlling Factors in the Upper-Middle Reaches of Wujiang River].

The Wujing River, the largest river in Guizhou Province, is one of the most important water resources for social and economical development. Recently, with the fast population proliferation and rapid economic growth, the drainage basin is intensively interfered by anthropogenic activities. The hydrochemistry of surface water was analyzed from the upper-middle reaches of Wujiang River for investigating the hydrochemical characteristics and their main influencing factors. The results showed that the major cations of the four rivers were Ca²âº and Mg²âº, accounting for more than 70%, and the main anions were HCO3⁻ and SO4²â», occupying more than 85%. The hydrochemical characteristics in the four rivers were found to be of HCO3-Ca type, and mainly determined by the carbonate rock dissolution, while only a small proportion of them were of HCO3 · SO4-Ca type, reflecting the influence of SO4²â» from anthropogenic activities. Compared to hydrochemical data in 1999, there was an obvious increase in cations and anions concentrations, majorly in NO3⁻, SO2- ion concentrations, which were significantly affected by human activities. The Na⁺, K⁺ , Cl⁻ in the river mainly came from atmospheric precipitation, and Ca²âº, HCO3⁻, Mg²âº, mainly came from carbonate rocks dissolution, while NO3⁻ and SO4²â» mainly came from human activities. According to principal component analysis and correlation analysis, hydrochemical composition of Liuchong River was affected by human activity, and that in the upstream of Sancha River was controlled by atmospheric precipitation and the dissolution of carbonate rocks, that to the downstream was enhanced by human activities. The main ion of Maotiao River was controlled by atmospheric precipitation and carbonate rocks dissolution, and also affected by human activity. The Nanming River, the Qingshui river's tributary, was mainly affected by human activity, while the middle and lower reaches of Qingshui River were affected by both the atmospheric precipitation and human activity.

[Influence of Sulfuric Acid to Karst Hydrochemical and δ13CDIC in the Upper and Middle Reaches of the Wujiang River].

Groundwater and surface water from the Upper and Middle Reaches of the Wujiang River were sampled and analyzed for the hydrochemistry and Carbon isotope in DIC. Then hydrochemical characteristics and the main influencing factors were investigated, and the contributions of carbonate dissolution by sulphuric acid to total(Ca2+ + Mg2+) and HCO3 were calculated using the stoichiometry method. The results showed that the advantage cations of groundwater and surface water is Ca2+, which accounted for more than 50% and the advantage anions is HCO3- and SO(4)2-, which accounted for more than 85%. The hydrochemical characteristics of most samples were of Ca-HCO3 type, and a small part of HCO3.SO4-Ca, reflecting a few samples affected by SO(4)2- from human source. The δ13CDIC of groundwater and surface water, varying from -12. 98%o to -6. 36%o with a changeable molar ratio between (Ca2+ + Mg2+) and HCO3- of 1. 11 to 1. 90, indicated that sulfuric acid has an important influence on hydrochemistry and δ3CDIC. The contributions of carbonate dissolution by sulphuric acid to total (Ca2+ + Mg2+) and HCO3 in groundwater ranged from 20. 59% to 92. 87% (average 51. 50%), and from 11. 47% to 86. 69% (average 36. 90%). While the contributions of carbonate dissolution by sulphuric acid to total (Ca2+ + Mg2+) and HCO3- in surface water ranged from 56. 14% to 94. 55% (with an average of 76. 89%), and 39. 02% to 89. 66% (with an average of 64.24%), respectively, demonstrated that sulphuric acid is an important agent of carbon rock weathering. The results of this study have a great significance for the protection and development and utilization of water resources in the Wujiang River basin and for karst carbon cycle research.

Protective effect of Danggui (Radix Angelicae Sinensis) on angiotensin II-induced apoptosis in H9c2 cardiomyoblast cells.

BACKGROUND: Danggui (Radix Angelicae Sinensis) is an herb often used in Traditional Chinese medicine. It is used to promote blood flow and has been used in the treatment of myocardial ischemia-reperfusion injury in animal models. Angiotensin II (Ang II) has been shown to play important roles in mediating cardiovascular diseases, and may cause cardiac hypertrophy and apoptosis. This study aimed to investigate whether Danggui has protective effects on Ang II-induced apoptosis in H9c2 cardiomyoblast cells and study the mechanisms involved. METHODS: We evaluated the effect of Danggui on Ang II-induced apoptosis in an in vitro model. H9c2 cardiomyoblast cells were cultured in serum-free medium for 4 hr, then treated with Danggui (50, 100 µg/ml) 1 hr pre- or post-Ang II treatment. After a further 23 hr of culture, cells were harvested for analyses with assays for apoptosis markers and cell signaling pathways. RESULTS: Our results showed that Ang II induced upregulation of pro-apoptotic Bad, instability of the mitochondria membrane potential, cytochrome c release, caspase-9 and caspase-3 activation and cardiomyocyte apoptosis. Pre- or post-treatment with Danggui reversed all of the above Ang II-induced apoptotic effects in H9c2 cells. Furthermore, the JNK (SP600125) inhibitor completely blocked Danggui inhibition of caspase-3 activation in Ang II-treated H9c2 cells. CONCLUSIONS: Our results showed that Danggui either pre-treatment or post-treatment highly attenuated the Ang II-induced apoptosis in cardiomyoblast cells. The findings demonstrated that the anti-apoptosis effect of Danggui is mediated by JNK and PI3k inhibitors.

[Transported fluxes of the riverine carbon and seasonal variation in Pearl River basin].

The riverine carbon flux is a critical component of global carbon cycle. Riverine water samples were collected from eleven hydrometric stations in the main stream of Pearl River and its tributaries during April and July, 2012. The samples were analyzed for the space and seasonal distribution characteristics of the riverine suspended substance and carbon compositions. Carbon fluxes and erosion modulus of Pearl River basin were also estimated in Boluo, Shijiao, Gaoyao, namely Dongjiang, Beijiang, Xijiang, in these two hydrological seasons. The results showed that the total suspended substance (TSS) and organic carbon, including total particulate organic carbon (POC) and dissolved organic carbon (DOC) have higher concentration in the high-water season than that in the normal-water season. Dissolved inorganic carbon (DIC) has an overwhelming concentration compared to other carbon compositions in Pearl River basin. The DIC concentration shows an order of Xijiang, Beijiang and Dongjiang from high to low. The percentage of allogenic POC in Xijiang, Beijiang and Dongjiang are 78%, 72%, 26%, respectively, and C3 plants are the main sources of allogenic POC in those three tributaries. The transported fluxes of TSS, total carbon (TC), POC, particulate inorganic carbon (PIC), DOC, DIC, total particulate carbon (TPC) and total organic carbon (TOC) are 134 x 10(12),12.69 x 10(12), 2.50 x 10(12), 1.01 x 10(12), 1.13 x 10(12), 8.05 x 10(12), 3.51 x 10(12) and 3.65 x 10(12) g x a(-1), respectively, and the erosion modulus of those compositions are 309 x 10(6), 28.98 x 10(6), 5.75 x 10(6), 2.27 x 10(6), 2.56 x 10(6), 18.4 x 10(6), 8.02 x 10(6) and 8.31 x 10(6) g x (km2 x a)(-1), respectively. Compared with average values of global large rivers, the erosion modulus of DOC, POC, and TOC in Pearl River basin are higher than the corresponding values.