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Carbon nitride (CN) has been widely used in photomineralization of phenolic pollutants, during which avoiding the production of refractory polymers induced by hydroxyl radical (•OH) is the key. In CN photocatalytic system, O 2 firstly reduces to superoxide radical (O 2 •-), then transforms into hydrogen peroxide (H 2 O 2) via reduction and protonation process, finally reduces into •OH. In this study, OH/C V -CN, hydroxyl groups (–OH) and carbon vacancies (C V) co-modified CN, was designed for phenol photomineralization. –OH, not only act as the adsorption sites for phenol through O···H–O bond, but also assist introducing C V into CN during roasting process. C V , active sites for reducing O 2 to O 2 •-, is close to adsorption sites of phenol, which greatly promotes the in-situ mineralization of phenol by O 2 •- and avoids the polymerization induced by •OH. Therefore, –OH and C V in OH/C V -CN synergistically facilitate the photomineralization of phenol. [Display omitted] • –OH, not only act as the adsorption sites for phenol through O···H–O bond, but also assist introducing C V into carbon nitride through adjusting the electron distribution on the adjacent heptazine. • C V , locating on the same heptazine ring with –OH, realize the rapid transformation of O 2 to O 2 •- as O 2 adsorption sites. • O 2 •- in-situ mineralize phenol instead of reducing to •OH profited from the shorter distance between O 2 •- and adsorbed phenol on OH/C V -CN than CN, which facilitates effective photomineralization of phenol and cleverly prevent forming polymer. Carbon vacancies Carbon nitride (CN) has been widely used in photomineralization of phenolic pollutants, during which avoiding the production of refractory polymers induced by hydroxyl radical (•OH) is the key. In CN photocatalytic system, O 2 firstly reduces to superoxide radical (O 2 •-), then transforms into hydrogen peroxide (H 2 O 2) via reduction and protonation process, finally reduces into •OH. In this study, OH/C V -CN, hydroxyl groups (–OH) and carbon vacancies (C V) co-modified CN, was designed for phenol photomineralization. –OH, not only act as the adsorption sites for phenol through O···H–O bond, but also assist introducing C V into CN during roasting process. C V , active sites for reducing O 2 to O 2 •-, is close to adsorption sites of phenol, which greatly promotes the in-situ mineralization of phenol by O 2 •- and avoids the polymerization induced by •OH. Therefore, –OH and C V in OH/C V -CN synergistically facilitate the photomineralization of phenol. [ABSTRACT FROM AUTHOR]

[Display omitted] • High-performance interfacial heterojunction, formed between OH PCN and Nb 2 O 5 via C O H O Nb bond, accelerates the carrier transfer from conduction band of Nb 2 O 5 to that of OH PCN. • The electron transfer occurred in C O H O Nb bond induces electron-rich O site, which act as an ideal adsorption site for phenol through O H ··· O hydrogen bond. • Super active site, formed by integrating triazine ring site on OH-PCN (activation site for O 2) and O site on Nb 2 O 5 (adsorption site for phenol), facilitates the evolution of O 2 and in-situ photomineralization of phenol. Promoting the carrier separation and surface catalytic reaction are critically important to maximize photocatalytic efficiency. Hydroxyl group-modified polymeric carbon nitride/niobium pentoxide nanosheets heterojunction (OH-PCN/Nb 2 O 5) is designed for fast electron transfer from Nb 2 O 5 to OH-PCN. Electron-rich O site, induced by electron transfer occurred in C O H O Nb bond, acts as an ideal adsorption site for phenol through O H⋯O bond. Super active site, formed by integrating triazine ring site on OH-PCN (activation site for O 2) and O site on Nb 2 O 5 (adsorption site for phenol), facilitates the evolution of O 2 and in-situ photomineralization of phenol. OH-PCN/Nb 2 O 5 shows a more than 8-fold improvement in phenol photodegradation efficiency than PCN. Briefly, this work provides insights on constructing interfacial super active sites by interface control of catalysts and in turn dramatically improving the photocatalytic performance. [ABSTRACT FROM AUTHOR]

Physical agricultural drought indices generally use soil moisture to represent root‐zone water availability (RZWA). The uncertainty in root‐zone properties, especially in deep‐rooting regions, may lead to significant uncertainty in the results. This study adopted a conceptual model that requires no specific root‐zone properties to model the RZWA. A RZWA‐based drought index (AgDI) was then developed by standardizing the root‐zone water deficit. A comparison over 20 catchments with different terrain and vegetation demonstrated the effectiveness of AgDI in characterizing agricultural droughts, with the correlations between vegetation indices (normalized difference vegetation index [NDVI] and gross primary productivity [GPP]) and AgDI (mean ~0.54) being significantly higher than those between the same vegetation indices and the Palmer Drought Severity Index (PDSI, ~0.22), Standardized Precipitation‐Evapotranspiration Index (SPEI, ~0.33), and Standardized Soil moisture Index (SSI, ~0.37). Compared to the SSI, the AgDI was not equally advantageous everywhere, but it generally showed better performance in deep‐rooting regions. Plain Language Summary: Agricultural drought can adversely affect agroecosystems; therefore its detection and quantification are essential for hazard mitigation. Limited root‐zone water availability (RZWA) is the direct cause of agricultural drought. Generally, physical agricultural drought indices are based on the soil moisture of several soil layers (e.g., 0–100 cm). However, these methods may result in uncertainties because the soil moisture in such soil profiles may not fully reflect the RZWA, especially in deep‐rooting ecosystems. In addition, estimation of RZWA is challenging because of the uncertainty in root‐zone properties (e.g., roots distribution and hydraulic properties). To overcome these known limitations, we developed a conceptual model that does not require root zone properties to model the RZWA, using which a new agricultural drought index (AgDI) was then developed by standardizing the root zone water deficit. A comparison study over 20 catchments with different terrain and vegetation properties showed that the AgDI is more effective in characterizing agricultural drought than the PDSI, SPEI and SSI. Compared to the soil moisture based SSI, the AgDI is not advantageous everywhere but generally exhibits better performance in deep‐rooting regions. We also found that the meteorological droughts are the main triggers of, but do not always lead to, agricultural droughts. Key Points: RZWA was inferred by using a conceptual model needing no specified root‐zone propertiesOur RZWA‐based drought index (AgDI) is effective in characterizing agricultural droughtsThe AgDI generally performs better in deep‐rooting regions than soil moisture based indices [ABSTRACT FROM AUTHOR]

Highlights • A dynamic Budyko model was improved by linking climate and vegetation. • Catchments with larger portion of karst landform (POK) have lower vegetation available water. • Evapotranspiration in catchments with larger POK rely more on precipitation. Abstract Karst landscape, covers more than 10% of the global land surface and plays an important role in supporting ecosystems and human society, may be strongly influenced by climate change. Vegetation available water (VAW) is a key variable impacting the sensitivity of ecosystems to a changing environment. However, VAW in karst region is difficult to determine and remains uncertain. This study improved a dynamic Budyko-type water balance model, by introducing a nonlinear equation linking climate, vegetation and Budyko-type water balance. This model was calibrated using evolutionary algorithm based on monthly runoff. Comparison results in the Pearl, Yangtze and 12 karst catchments in south China, suggested high effectiveness of this improved model in simulating monthly runoff and evapotranspiration. Furthermore, in the 12 karst catchments, the max VAW was negatively correlated to the portion of karst landscape of the catchment (POK, r = −0.63, α = 0.027) and the elasticity of evapotranspiration to precipitation (r = −0.60, α = 0.04). These implied that karst catchments with higher POK had lower VAW, making the ecosystems rely more on precipitation. [ABSTRACT FROM AUTHOR]

ABSTRACT: Southwest (SW) China is a drought prone region. Knowledge of the risks and coupling characteristics of drought duration and severity is essential for hazards mitigation and water management. Based on probability distributions, copulas, Mann–Kendall test, overlapping moving windows approach and the self‐calibrated Palmer Drought Severity Index (PDSI) at 69 stations (1959–2013), this study focused on the trends and spatial variability (SV) of (joint) probability drought duration and severity in SW China, and further investigated the potential contributors by analysing the behaviours of precipitation (P), temperature (T), relative humidity (RH), wind speed (WS), atmospheric moisture flux (MF) and divergence (MFD). In particular, the SV was represented by the standard deviation, the drought duration and severity were characterized by the number of months with PDSI < −0.5 in a year [drought months (DM)] and the absolute mean PDSI in drought months (DS), respectively. Results showed that, the DM, DS, DM5, DS5 (5‐year return levels for DM and DS) increased by 0.058 month year−2, 0.012 month−1 year−1, 0.039 month year−2, and 0.009 month−1 year−1, respectively, and the joint return period T(DM > 4,DS > 2) decreased by −0.20 year year−1. Furthermore, due to the decreasing SV in P, T, RH, WS, MF, and MFD, SV of DM5, DS5 and T(DM > 4,DS > 2) significantly decreased in the past decades, by −0.003 month year−2, −0.006 month−1 year−1 and −0.03 year year−1, respectively. These results indicated that drought risks and severity increased significantly in the past decades over SW China. Most importantly, the decreasing SV implied that drought risks and severity might have become more homogeneous in this region. In other words, droughts became more widely spread throughout SW China in the past decades. Therefore, water agencies and governments should be more proactive in seeking measures to improve water resources management and drought mitigation in this region. [ABSTRACT FROM AUTHOR]

[Display omitted] • N V guarentee the evolution of O 2 to H 2 O 2 as O 2 exclusive adsorption sites, which improves the efficiency of photopurification work. • –CN, substitutes for hydrogens in primary amines, offer the opportunity for controlling reaction selectivity by inhibiting H 2 O 2 randomly decomposing to •OH. • The steric hindrance effect between N3C and SO induced by –CN and N V prevents H 2 O 2 reducing to •OH enabling the stable presence of SO. The key of photopurification, a bran-new technique for substance purification, is selective mineralization by surface modification of photocatalyst. CN/N V -PCN, nitrogen vacancies (N V) and cyano groups (–CN) co-modified polymeric carbon nitride (PCN), selectively photomineralize benzaldehyde (BZ) in industrial styrene oxide (SO) production solution. N V , special O 2 adsorption sites, guarantee the activation of O 2 to H 2 O 2. –CN, substitutes for hydrogens in terminal amines (–NH 2), inhibit H 2 O 2 randomly decomposing to •OH on –NH 2 sites. N V and –CN adjust the electronic distribution on triazine ring and H to reinforce π-π interaction and O···H N bond between PCN and SO, narrowing the space between benzene ring and N3C site, in which the steric hindrance effect hinders H 2 O 2 reducing to •OH by e- on N3C site. •OH can only produce at the adsorption sites of BZ, which results the selective mineralization of BZ. This work provides not only a modification method of PCN for selective oxidation reaction, but also a bran-new technique for removing homogeneous trace impurities in natural or industrial products. [ABSTRACT FROM AUTHOR]

Transferrin (Transferrin, TRF, TF) has drawn increasing attention in cancer therapy due to its potential applications in drug delivery. TF receptor, highly expressed in tumor cells, recognizes and transports Fe 3+ -TF into cells to release iron into cytoplasm. Thus, discovering TF-binding compounds has become an active research area and is of great importance for target therapy. In this study, an on-line analysis method was established for screening TF-binding compounds from the flowers of Bauhinia blakeana Dunn using a high-performance liquid chromatography–diode-array detector–multi-stage mass spectrometry–transferrin–fluorescence detector (HPLC–DAD–MS n –TF–FLD) method. As a result, 33 of 80 identified or tentatively characterized compounds in the sample were TF-binding active. Twenty-five flavonol glycosides and eight phenolic acids were identified as TF-binders. Twelve of these active compounds together with six standard compounds were used to study the dose-response effects and structure-activity relationships of flavonoids and phenolic acids. The method was validated by vitexin with a good linearity in the range of concentrations used in the study. The limit of detection for vitexin was 0.1596 nmol. Our study indicated that the established method is simple, rapid and sensitive for screening TF-binding active compounds in the extract of Bauhinia blakeana Dunn, and therefore is important for discovering potential anti-cancer ingredients from complex samples for TF related drug delivery. [ABSTRACT FROM AUTHOR]

Summary Karst landform represents about 10% of the continental area and plays key roles in water supplies for almost a quarter of the global population. Knowledge of ecohydrological responses of karst landform to climate change is critical for both water resources management and ecological protection in these regions. This study investigated the effects of karst landform on the elasticity of actual evapotranspiration (derived by the Budyko equation), estimated the contribution of climate change and evaluated the implications, on the basis of 13 typical catchments that have different karst landform coverages in southwest China. Catchment properties, including the vegetation coverage, portion of karst landform (POK), drainage area, surface roughness, mean topographic wetness index, mean slope, and mean aspect, were selected to test the influencing factors for the elasticity of actual evapotranspiration. Results indicate that POK is the most influencing factor for the elasticity of actual evapotranspiration in this region. Moreover, the actual evapotranspiration in karst catchments is more sensitive to precipitation change and less sensitive to the potential evapotranspiration change than that in the non-karst catchments. On the other hand, the contribution of climate change to actual evapotranspiration was generally negative in this region. Furthermore, relatively large negative contributions mainly occurred in the karst-dominated catchments, suggesting that the karst catchments were exposed to higher degradation stress brought by the climate change than that in non-karst catchments. [ABSTRACT FROM AUTHOR]

A high-performance liquid chromatography-diode array detector-electrospray ionization-ion trap-time of flight-mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS) method was established for excellent separation and structural identification of constituents in Shuang–huang–lian powder injection (SHLPI). The typical ultraviolet absorptions, accurate empirical molecular formula and reasonable fragmentation mechanisms of these ingredients were used for their structural elucidation. In consequence, 125 constituents (33 phenolic acids, 29 flavonoids, 32 phenylethanoid glycosides, 15 iridoid glycosides, 8 lignans, 3 amino acids and 2 purines nucleosides, 2 quinoid glycosides and 1 alkylbenzene glycoside) were either unequivocally identified or tentatively characterized by comparing authentic standards or published data. The result showed that this study could provide valuable information for the quality control and further investigation of SHLPI formula. [ABSTRACT FROM AUTHOR]

Availability of high-resolution satellite rainfall products provides a great opportunity to monitor precipitation frequently over large and remote areas. However, the accuracies of these products need thorough assessment before they can be widely used. The objective of this study is to evaluate the accuracies of Tropical Rainfall Measuring Mission Multisatellite Precipitation Analysis 3B42 products (TMPA V6 and TMPA V7) using a network of 75 rain gauges over Southwestern China. The study region has a complex terrain, which makes it challenging for TMPA rainfall products to give reliable estimates. The results show that the TMPA products tend to underestimate the occurrences of rainfall events. Furthermore, TMPA V6 always underestimates the precipitation, while V7 generally overestimates rainfall in wet season and underestimates it in dry season. Under- and overestimation of rainfall by the two products can be mainly attributed to false alarm events. The overall accuracies of the two products depend heavily on the time scale. At the daily scale, these products may not be reliable; however, the overall accuracies are improved substantially when the time scale is extended from daily to monthly and seasonal scales. Reliability of the TMPA precipitation estimates is also dependent on the climate zones and elevation to some extent and shows clear seasonal variations. In the wet months from May to September, the estimates for TMPA 3B42 V6 and V7 tend to be more accurate. In comparison, the accuracy of V7 is improved slightly over V6. However, V7 still has some major limitations in reproducing precipitation in dry seasons and in high-elevation regions with complex terrains, suggesting that further improvements in TMPA precipitation retrieval algorithms are still needed for this type of regions. [ABSTRACT FROM AUTHOR]

• Introducing climate (CS) and vegetation seasonality (VS) into the Budyko framework. • CS and VS jointly contribute more than the changes in P and ET 0 in water partitioning. • In average the contributions of VS and CS in water partitioning are equally important. Climate and vegetation changes are main factors influencing water partitioning. However, their impacts on water partitioning are still not well understood. To revisit the interactions among climate, vegetation and water partitioning, this study introduces the climate seasonality (CS) and vegetation seasonality (VS) into the Budyko framework, by using a statistical approach combining the three-parameter Log-logistic probability distribution and multiple linear regression, based on the monthly 〈 P - ET 0 〉 (precipitation (P) minus potential evapotranspiration ( ET 0)) and Normalized Difference Vegetation Index (NDVI). This method is then validated and applied in 86 global catchments to quantify the contribution of climate and vegetation changes to evapotranspiration (ET). Results show that this model can predict well (mean R 2 = 0.81 ± 0.05, P < 0.05) the parameter n , a parameter reflecting the interactions between land surface and atmosphere in the Budyko framework. More importantly, CS and VS jointly control the variation in parameter n , and in average jointly contribute more (mean relative contribution of 57.1 ± 2.3 %) than the changes in P and ET 0 (mean of 42.9 ± 2.3%) to ET. These indicate that CS and VS are at least as important as the changes in P and ET 0 in affecting water balance. Furthermore, the VS contributes slightly lower (mean of 24.9 ± 0.3%) than the CS does (mean of 32.2 ± 2.3%), implying that CS and VS play comparable roles in water partitioning. These findings would be valuable for water resources management and assessing the impacts of climate and land surface changes on water balance in a gradually changing environment. [ABSTRACT FROM AUTHOR]

A 2-year experiment was carried out to investigate the effects of different drip irrigation regimes on distribution and dynamics of soil water and salt in north Xinjiang, China. Five treatments-F7 (0.24 dS m + Once every 7 days), B7 (4.68 dS m + Once every 7 days), S7 (7.42 dS m + Once every 7 days), F10 (0.24 dS m + Once every 10 days) and F3 (0.24 dS m + Once every 3 days)-were designed. For all treatments, additional 150-mm fresh water was applied on 10th November in 2009 (winter irrigation) to leach the accumulated salt. The results revealed that irrigation frequency and water quality had significant effects on the spatial distribution and change of soil water content, soil salt and the crop water consumption rate, but had a limited impact on the seasonal accumulative water consumption, and the cotton yield decreased with the decrease in irrigation frequency and water quality on the whole. During the cotton growing season, results showed that the salt mainly accumulated in the 0- to 60-cm soil layer, while the soil salt in 60- to 100-cm layer changed slightly, indicating that the drip irrigation could not leach the soil salt out of the root zone under the irrigation regimes. Therefore, salt leaching was necessary to maintain the soil water-salt balance and to prevent excessive salt accumulation in the root zone. After the 150-mm winter irrigation and subsequent thawing, soil salts were leached into the deeper layers (below 60 cm), and the soil salt content (SSC) (EC) in root zone in the next year was about 0.2 dS m. Moreover, compared to 2009 season, the SSC within the root zone did not increase even the EC of the irrigation water was up to 7.42 dS m. Additionally, it is important to note that the results were concluded based on the data of the 2-year experiment; further studies are need to optimize winter irrigation amount and assess the sustainability of saline water irrigation since long-term utilization of saline water may lead to soil degradation. [ABSTRACT FROM AUTHOR]

• Solving phenol polymerization problem by tailoring H 2 O 2 formation and transformation via CN modification. • Improved charge separation and subsequent in-situ decomposition of H 2 O 2 to OH due to phenol adsorption. • In-situ IR spetrascopy as a powerful tool to investigate the active sites and surface reaction pathway for phenol photodegradation. The electronic and interfacial properties of catalysts play vital roles in tailoring catalytic performance. Here, we report that the modification of polymeric carbon nitride (PCN) with cyano group (CN) can achieve excellent catalytic performance in mineralization of phenol. The CN site not only enhances the adsorption and activation of molecular O 2 for efficient H 2 O 2 production, but also improves the absorption capability of PCN for phenol in aqueous solution by tuning surface charge states. Subsequently, the surficial adsorbed phenol acts as holes scavenger which promotes the separation efficiency of photogenerated carriers in PCN and in turn facilitates the in-situ decomposition of H 2 O 2 to OH. This reduces the uncontrollable decomposition of H 2 O 2 to OH and inhibits the polymerization of phenolic compounds. The active sites of catalyst, O 2 transformation state and pathway on the catalyst surface as well as the firstly attacked sites of phenol are confirmed respectively by in-situ DRIFT spectra, scavengers and Bader charge analysis. [ABSTRACT FROM AUTHOR]

• A 3D-LC-MS-based proteomics method was developed to detect trace proteins in serum. • Triclosan (TCS) metabolites could covalently bind to proteins via cysteine residues. • 45 proteins were found to be modified by TCS metabolites in rats. • Modified proteins were found to be related with TCS-induced adverse effects. • Covalent protein modification is a possible reason of TCS-induced adverse effects. Triclosan (TCS), an antimicrobial agent widely used in personal care products and ubiquitously exists in environment, has drawn increasing concern due to its potential to exert multiple adverse effects, ranging from endocrine disruption to carcinogenesis. However, the mechanism of these adverse effects is still not fully elucidated. More and more studies have shown that chemical reactive metabolites (RMs) covalently binding to proteins is a possible reason for these adverse effects, but there is still a lack of appropriate methods to predict or evaluate these adverse effects due to the extremely low abundance of the modified proteins in complex biological samples. In this study, we attempted to address this problem and investigate the possible mechanism of TCS adverse effects by a shotgun proteomics approach based on three-dimensional-liquid chromatography-mass spectrometry (3D-LC-MS). First, the in vitro incubation with model amino acids and protein in microsomes showed that TCS could react with cysteine residue of proteins through 3 types of RMs. Then, a 3D-LC-MS approach was developed to sensitively determine the low abundant modified proteins, which resulted in the identification of 45 TCS-modified proteins, including albumin, haptoglobin and NR1I2, in rats. STRING analysis indicated that these modified proteins mainly were involved in reproductive and development system, endocrine and immune system, and carcinogenesis, which were in accord with the main reported TCS-induced adverse effects and suggested that the covalent modification of TCS RMs for proteins might affect their activities and functions, thus inducing serious adverse effects. This study provided a new insight into the mechanism of TCS adverse effects and may serve as a valuable method to predict or evaluate adverse effects of ubiquitous chemicals. [ABSTRACT FROM AUTHOR]

The CuMgAl ternary hydrotalcite (CuMgAl) has been reported to achieve the decomposition of H 2 O 2 to OH for hydroxylation of phenol, and the key active site is Cu+. The Cu2+ must be converted to Cu+, which is a slow step that lowers the total reaction efficiency. Herein, the partially oxidized MoS 2 loaded CuMgAl (PO-MoS 2 /CuMgAl-1.12) sample was designed to overcome this issue. As a variable valence metal the Mo can partly tune the Cu2+ to Cu+ by forming Mo O Cu electron transport system which enhances the catalytic performance of our catalyst. Unlabelled Image • The partically oxidised MoS 2 (PO-MoS 2) was loaded on CuMgAl hydrotalcite catalyst (PO-MoS 2 /CuMgAl-1.12) by a simple hydrothermal treatment. • It is the first report that PO-MoS 2 /CuMgAl-1.12 exhibits improved efficiency for the decomposition of H 2 O 2 and the hydroxylation of phenol than the original CuMgAl hydrotalcite. • It is infferred that the improved efficiency is due to the contruction of a Mo-O-Cu electron transfer system, which can in situ adjust the valence state of copper ion from Cu2+ to Cu+ during the catalytic reaction cycle and accelerate the reaction rate. [ABSTRACT FROM AUTHOR]

Regulating the surface properties of catalysts to control the selectivity of a reaction is a fascinating approach. Bulk polymeric carbon nitride exhibits a poor N-phenylhydroxylamine yield in nitrobenzene reduction reaction mainly due to the uncontrollable condensation side reactions. Thus, adjusting the structure of the catalyst was key to solving the above issue. Herein, –OH groups-modified polymeric carbon nitride was prepared via a simple hydrothermal treatment. With the introduced –OH groups replacing the terminal amino groups (–NH2) at the surface of the polymeric carbon nitride, a 3-fold increase in reaction rate was achieved, along with a high selectivity toward N-phenylhydroxylamine (ca. 80%). The introduced –OH group was found to be beneficial to the adsorption of the nitrobenzene, based on the density functional theory (DFT) calculation. It could also lower the recombination rate of photoinduced electron–hole pairs, which would accelerate the photocatalytic oxidation of isopropanol and supply more protons to participate in the hydrogen-transfer process. Moreover, the elevated conduction band position after –OH modification would provide high energetic photogenerated electrons to promote the reduction of nitrobenzene. These are all important to guarantee the highly selective production of N-phenylhydroxylamine. This paper not only provides a simple and green approach for the modification of polymeric carbon nitride toward an efficient photocatalyst, but also sheds light on the further study of the selective hydrogenation. [ABSTRACT FROM AUTHOR]

Karst landscape, covers more than 10% of the global land surface and plays an important role in supporting ecosystems and human society, may be strongly influenced by climate change. Vegetation available water (VAW) is a key variable impacting the sensitivity of ecosystems to a changing environment. However, VAW in karst region is difficult to determine and remains uncertain. This study improved a dynamic Budyko-type water balance model, by introducing a nonlinear equation linking climate, vegetation and Budyko-type water balance. This model was calibrated using evolutionary algorithm based on monthly runoff. Comparison results in the Pearl, Yangtze and 12 karst catchments in south China, suggested high effectiveness of this improved model in simulating monthly runoff and evapotranspiration. Furthermore, in the 12 karst catchments, the max VAW was negatively correlated to the portion of karst landscape of the catchment (POK, r=-0.63,α=0.027) and the elasticity of evapotranspiration to precipitation (r=-0.60,α=0.04). These implied that karst catchments with higher POK had lower VAW, making the ecosystems rely more on precipitation. [ABSTRACT FROM AUTHOR]

The critical zone (CZ) represents the intersection of the biosphere with the atmosphere, hydrosphere and lithosphere. Understanding the hydrological processes and human impact factors on the CZ is fundamental to sustainable water resources management for agroforestry. Transpiration (T) is an important component of terrestrial evapotranspiration (ET), and understanding the time lag (TL) between vegetation transpiration and meteorological factors can improve our knowledge of the mechanisms of vegetation adaptability to a changing environment. However, the controlling factors on the TL remain poorly understood. Therefore, the objective of this study is identifying the temporal dynamics of key controlling factors on the TL, using a typical deciduous broad-leaved tree species (Zenia insigins Chun) of CZ in subtropical humid karst regions. This species is used as an example to explore the characteristics of the TL between SF (sap flow) and hydro-meteorological forcing. Sap flow in these 6 trees was monitored using the thermal dissipation probes (TDP). Results showed that: (1) the peak of diurnal sap flow generally lagged behind PAR but preceded Ta (air temperature), RH (relative humidity) and VPD (vapor pressure deficit), with the mean TL of −67.4 min (PAR), 90.5 min (Ta), 91.6 min (RH) and 92.9 min (VPD), respectively; (2) TL had no significant relationships with the daily mean meteorological factors and soil moisture, but was highly (R2>0.66) correlated to CRs (changing rates of meteorological factors) in the morning; (3) At seasonal scale, the sap flow rate and TL both were controlled by the seasonality of precipitation and temperature. Overall, the seasonality of the TL was caused by plants' high water loss and strongly active physiological response in hot seasons, leading to close stomata earlier than in cold seasons; (4) The reason why CRs proposed can explain the TL better than mean values of metrological factors is that the CRs considered the distribution and change processes of metrological factors in the daytime. This study may be helpful for understanding the physiological response of vegetation to climatic change, and may be useful for constructing models to simulate transpiration processes more accurately during a day. [ABSTRACT FROM AUTHOR]

Polymeric carbon nitride is a promising candidate for metal-free photocatalysis, but it is hampered by low activity due to poor carrier separation efficiency and lack of active sites. We have constructed a bifunctionally-modified structure, containing cyano groups internally and carboxyl groups on the surface, that was about 205 times more active than unmodified carbon nitride. The internal cyano groups enhanced the photoelectric performance of carbon nitride, while the surface carboxyl groups acted as active sites to promote hydrogen production. It is anticipated that this work will inform the rational design of polymeric carbon nitride and inspire similar attempts to modify polymers. [ABSTRACT FROM AUTHOR]

Understanding evapotranspiration–vapor pressure deficit ( ET - VPD ) hysteresis for different ecosystems can improve our knowledge of vegetation adaptability to a changing environment. However, no previous studies have compared the controlling factors of ET - VPD hysteresis for different agroforestry ecosystems in karst landscapes. Therefore, this study explored ET - VPD hysteresis patterns and the controlling factors for three agroforestry ecosystems, using field observations in a subtropical humid karst catchment from March 12, 2015 to May 26, 2016. The results showed both similarities and differences in ET - VPD hysteresis among the three ecosystems. For example, all three agroforestry ecosystems exhibited noticeable ET - VPD hysteresis, and the hysteric magnitude showed noticeable seasonality with higher values during the growing season. For all three ecosystems, the ET - VPD hysteretic magnitude had no significant relationship with the daily mean environmental factors (e.g. meteorological factors and soil moisture ( θ )), but it was highly ( R 2 > 0.59) correlated to changing rates of meteorological factors (e.g. temperature ( Ta ), relative humidity ( RH ), and vapor pressure deficit ( VPD )) in the morning. The ET - VPD hysteretic magnitude of the forest–grass mixed ecosystem (142.48 ± 74.16 min) was significantly higher than that of the grass ecosystem (104.37 ± 82.93 min). Hysteresis reflected the extent of imbalance between water demand and water supply for ecosystems during a day. Therefore, this study may be helpful in modeling ET and further understanding ecosystem responses to environmental change. [ABSTRACT FROM AUTHOR]

Karst landforms account for 10% of the Earths land surface, and it is well-known that water is a limiting factor for karst ecosystems because numerous underground fractures and conduits induce rapid drainage. Therefore, an understanding of ecosystem water consumptions (evapotranspiration) and environmental controls is particularly important for land management on karst landforms. This study compared the actual evapotranspiration ( AET) characteristics and analyzed the controls of three agroforestry ecosystems by field observations using a refitted ventilated-chamber, thermal dissipation probes and micro-lysimeters in a subtropical humid karst catchment from 12th March 2015 to 26th May 2016. Results show that: 1) the diurnal transpiration curves of trees plateau at noon with low fluctuations at a high level, while evapotranspiration curves of grass and crop ecosystems present single peaks; 2) AET of the forest-grass mixed ecosystem (7.64 ± 5.75 mm·day −1 ) was significantly higher than crop (4.24 ± 3.35 mm·day −1 ) and grass ecosystems (5.78 ± 3.53 mm·day −1 ); 3) AET of grass and crop ecosystems were most sensitive to temperature, while the forest-grass mixed ecosystem was more sensitive to leaf area index ( LAI ) than other factors; 4) AET of the forest-grass mixed ecosystem was more sensitive to deep soil moisture (>30 cm), while grass and crop ecosystems were more sensitive to shallow soil moisture (10 cm and 20 cm). This study suggests that soil water content was not key limit factors to AET in humid karst landscapes . However, LAI , which can be controlled by land management, heavily influenced AET rates and E / AET ( E , evaporation) ratio through changing water demand. [ABSTRACT FROM AUTHOR]

Indicating soil quality usually requires many soil properties of which the measurements are time consuming. Therefore, it is desirable to developing simple and effective indices for reflecting soil quality based on soil properties that can be readily obtained. The soil physical quality index, S-index, derived from the slope at the inflection point of the water retention curve (particularly the Van-Genuchten equation), is a comprehensive index for indicating soil properties. By comparing the S-index with a widely used soil quality index (SQI), this study used 298 samples to determine soil chemical and physical properties for calculating SQI, and found that the correlation coefficient between the S-index and SQI was 0.88, indicating that the S-index can represent soil quality well. An artificial neural network (ANN) model and a linear regression (LR) model were proposed for estimating S-index. Results showed that the ANN model was better than LR model in estimating S-index. Particularly, the ANN model with the soil bulk density and soil organic carbon (scenario A1) as inputs, had the highest R 2 of 0.807, while the LR model get the highest R 2 (predicted v.s. observed) of 0.75 with the combination of soil organic carbon, soil bulk density, total nitrogen and available nitrogen. This study is helpful for extending the applications of S-index. [ABSTRACT FROM AUTHOR]

As one of the largest karst regions in the world, southwest China is experiencing severe soil erosion due to its special geological conditions, inappropriate land use, and lower soil loss tolerance. Knowledge and accurate estimations of changes in sediment discharge rates is important for finding potential measures to effectively control sediment delivery. This study investigated temporal variation in monthly sediment discharge ( SD ), and developed sediment rating curves and state-space model to estimate SD . Monthly water discharge, SD , precipitation, potential evapotranspiration, and normalized differential vegetation index during 2003–2015 collected from a typical karst catchment of Yujiang River were analyzed in present study. A Mann-Kendal test and Morlet wavelet analysis were employed to detect the changes in SD . Results indicated that a decreasing trend was observed in sediment discharge at monthly and annual scale. The water and sediment discharge both had a significant 1-year period, implying that water discharge has substantial influence on SD . The best state-space model using water discharge was a simple but effective model, accounting for 99% of the variation in SD . The sediment rating curves, however, represented only 78% of the variation in SD . This study provides an insight into the possibility of accurate estimation of SD only using water discharge with state-space model approach. State-space model is recommended as an effective approach for quantifying the temporal relationships between SD and its driving factors in karst regions of southwest China. [ABSTRACT FROM AUTHOR]

Soil pedotransfer functions (PTFs) are alternatives to expensive field and laboratory methods for acquiring soil hydraulic properties. Traditional PTFs generally require soil physiochemical properties (such as particle size distribution, bulk density, soil organic matter, etc.) as inputs. Soil spectral information is, more recently, being considered as an additional input property for improving the performance of PTFs. To date, however, there are only a few studies focused on this issue. Using 171 in-situ saturated soil hydraulic conductivity (Ks) observations in southwestern China and an Artificial Neural Network model (ANN), we developed three different PTFs, with different inputs, to estimate the saturated hydraulic conductivity. The inputs include the basic soil properties (denoted as BSP, bulk density, % clay, % silt and % sand) and soil spectral data (SPRD, dimension reduced by using the principal component analysis (PCA) method). We evaluated the performance of the new PTFs using the determination coefficient (R 2 ), root mean square error (RMSE) and Akaike's information criterion (AIC). The results showed that including the SPRD as an additional input improved the performance of the PTF for estimating Ks. Compared to the PTF that solely used BSP as inputs, the R 2 of the PTF, which used both the BSP and SPRD as inputs, increased by 0.33 (from 0.09 to 0.42) and the RMSE and AIC decreased by 0.26 (from 1.38 to 1.12) and 18.16 (from 273.96 to 255.8), respectively. These results indicate the potential of SPRD to improve the performance of PTF in estimating hydraulic conductivity. [ABSTRACT FROM AUTHOR]

Soil hydrologic functions are important for karst landscapes where soil water loss is significant. The largest global ecological restoration engineering project, namely the “Grain for Green” program, is being implemented since 2000 in karst landscapes across southwestern China. However, its effects on soil hydrologic functions are still unknown. Using data acquired in field investigations and a generalized linear model (GLM), this study examines the effects of different vegetation restoration types on soil field saturated-hydraulic conductivity ( K fs ) in karst landscapes of southwest China. The results indicate that the K fs of artificial grassland (napiergrass) was higher than in other vegetation restoration types (zenia insignis, toona sinensis, orchard, and natural restoration shrubland) and cropland at both the surface and 10 cm depths. The K fs of vegetation restoration lands was lower than that of Mulun nature reserve (primary forest) at both the surface and 30 cm depths. We found significant differences of K fs in different depths of vegetation restoration lands but not significant for primary forest. The GLM model explains 64.75% of the total variation in K fs . Among the input variables, vegetation type explained the largest proportion (11.29%) of the variation, followed by bulk density (BD), soil organic carbon, and BD and vegetation type interactions. The factors above were significantly related to K fs . This study suggests that the implementation of different vegetation restoration types can alter soil hydrologic functions and provides useful knowledge for ecological restoration practices and management in karst landscapes. [ABSTRACT FROM AUTHOR]

Southwest China represents one of the largest continuous karst regions in the world. It is estimated that around 1.7 million people are heavily dependent on water derived from karst springs in southwest China. However, there is a limited amount of water supply in this region. Moreover, there is not enough information on temporal patterns of spring discharge in the area. In this context, it is essential to accurately predict spring discharge, as well as understand karst hydrological processes in a thorough manner, so that water shortages in this area could be predicted and managed efficiently. The objectives of this study were to determine the primary factors that govern spring discharge patterns and to develop a state-space model to predict spring discharge. Spring discharge, precipitation (PT), relative humidity (RD), water temperature (WD), and electrical conductivity (EC) were the variables analyzed in the present work, and they were monitored at two different locations (referred to as karst springs A and B, respectively, in this paper) in a karst catchment area in southwest China from May to November 2015. Results showed that a state-space model using any combinations of variables outperformed a classical linear regression, a back-propagation artificial neural network model, and a least square support vector machine in modeling spring discharge time series for karst spring A. The best state-space model was obtained by using PT and RD, which accounted for 99.9% of the total variation in spring discharge. This model was then applied to an independent data set obtained from karst spring B, and it provided accurate spring discharge estimates. Therefore, state-space modeling was a useful tool for predicting spring discharge in karst regions in southwest China, and this modeling procedure may help researchers to obtain accurate results in other karst regions. [ABSTRACT FROM AUTHOR]

Soil hydrologic functions are important for ecological restoration in karst landscapes where soil and water loss are serious. For examining how different strategies of Napier grass cultivation affect soil hydrologic function, and to identify reasonable strategies for maintaining soil hydrologic function, this study investigated the effects of 3 years’ (since 2011) Napier grass ( Pennisetum hydridum ) management on soil hydraulic properties (soil field-saturated hydraulic conductivity ( K fs ), water retention parameter ( α )) using an orthogonal experiment (form L 12 (4 2 × 3 1 )) in 2014. The management experiments included three levels for each of the following: nitrogen fertilization, cutting frequency and cutting intensity. Results showed that the farming practices (nitrogen fertilization, cutting frequency and cutting intensity) of Napier grass had higher influence on the soil hydraulic properties of the topsoil than those of the subsoil; nitrogen fertilization influenced the soil hydraulic properties more significantly than cutting frequency and cutting intensity. The K fs of the topsoil generally decreased with increasing nitrogen fertilization and cutting frequency. This study suggests that the implementation of different farming practices differently alters soil hydrologic functions. Hence, in karst landscapes where water resources are limited for agricultural production, the selection of optimal farming practices for high productivity should also take soil hydrologic functions into consideration. [ABSTRACT FROM AUTHOR]

Different medical treatment choices may affect the health of patients with chronic diseases. This study aims to assess the relationship between treatment choices, including the use of traditional Chinese medicine (TCM), and the health levels of middle-aged and elderly patients with six chronic diseases. The sample data comes from China Health and Retirement Longitudinal Study (CHARLS 2018). Basic conditions, medical choices and health status of patients are incorporated. The ordered Logit and Logit regression models are used to analyze and compare the effects of six chronic disease patients' medical options on their self-rated health (SRH) and depression. The overall average score of SRH is the highest in patients with heart disease (the worst in SRH), which is 3.433. Arthritis patients have the highest overall depression average score (depression) at 0.444. Under the premise of controlling a variety of socio-demographic factors, compared with the non-treatment group, taking TCM has a significant positive effect on SRH of patients with five diseases except hypertension. Both taking western medicine (WM) and taking integrated Chinese and Western medicine (IM) have a significant positive effect on SRH scores of patients with six chronic diseases in middle and old age. Taking TCM has effect on depression of patients with heart or stomach diseases, and taking WM and IM affects depression of middle-aged and elderly chronic patients except diabetes. Taking IM has a greater effect on SRH and depression of chronically ill patients, followed by taking WM, and the effect of taking TCM is relatively small, which is related to the development stage of the disease. Therefore, in the future, the control and treatment of chronic diseases in the middle and late stages can be discussed from the perspective of integrated traditional Chinese and western medicine, but attention should be paid to drug interactions. In order to improve the treatment rate and health level of patients with chronic diseases, their economic burden should be reduced, and they should be guided to choose more reasonable treatment methods. [ABSTRACT FROM AUTHOR]

Background: There may be differences in gender and marital status in the impact of grandchild care on the depression of the Chinese older adults. This research explores the effect of grandchild care on the depression of Chinese older adults of different genders and marital status, and explores the mediating role of intergenerational support from children between grandchild care and depression.Methods: This research uses the data of 3540 Chinese older adults from the China Health and Retirement Longitudinal Study (CHARLS) in 2018. The OLS model is used to analyze the effect of grandchild care on the depression of the older adults. and the older adults are classified according to gender and marital status, and the differences in the effect of grandchild care on the depression of the elderly of different genders and marital status is explored. Finally, the bootstrap method is used to test the mediating effect of intergenerational support from children.Results: The research finds that grandchild care has a significant impact on the depression of the older adults in China, and providing grandchild care can significantly reduce the depression of the older adults. The effect of grandchild care on the depression of the older adults is different between different genders and marital status. After categorizing the older adults by gender, the grandchild care only has a significant impact on the depression of female older adults; after classified by marital status, grandchild care only has a significant impact on the depression of the older adults who don't have a spouse. The mediating effect analysis shows that both children's emotional support and children's economic support have a mediating effect between grandchild care and depression of the older adults.Conclusion: The depression of the Chinese older adults is affected by grandchild care, and this effect is more prominent in female older adults and the older adults who don't have a spouse. The society should support and encourage capable older adults to participate in grandchild care, and children should also provide more intergenerational support to the older adults who provide grandchild care, so as to further play the role of grandchild care in relieving depression of the older adults. [ABSTRACT FROM AUTHOR]

Abstract Spatial distribution of soil moisture (SM) is a prerequisite for research and management of agriculture and ecology. However, it is still a challenge to retrieve SM data in highly heterogeneous landscapes. By investigating environmental factors (soil, vegetation and topography) and comparing different remote sensing sources (Landsat-8, Radarsat-2, ASTER Global Digital Elevation Model (DEM) V002 (ASTGTM2), unmanned aerial vehicle (UAV)) for karst mountainous catchments of southwest China, this study identified key controlling factors on the spatial distribution of SM and built a remote sensing model for SM estimation in highly heterogeneous landscapes. Results showed that vegetation type (35.7%), aspect (7.7%), height index (4.2%), soil bulk density (3.3%), soil total nitrogen (3.1%), aspect interact with vegetation type (3.4%) and soil total phosphorous (1.3%) totally explained 58.8% of the SM variability. The correlations between SM and topographic derivatives varied with DEM resolutions (1–50 m), and generally reached their highest values at 7 m for height index, slope gradient, and aspect, 16 m for flow accumulation and topographic wetness index, and 43 m for curvature. Partial least-squares regression analysis showed that optical and infrared bands from Landsat-8 and topographic derivatives from UAV photogrammetry DEM were more strongly correlated with SM than other datasets. An empirical model (SM = 9.27 ∗ 10−2 HI − 1.82 ∗ 10−5 B 5 + 0.519) with only height index and B5 band from Landsat-8 as inputs is proposed, as it shows acceptable performance (R2 = 0.36; RMSE = 0.076). The results of this study provide useful information for SM remote sensing in karst mountainous area and similar heterogeneous landscapes. Highlights • Vegetation is the major controlling factor for SM in karst region. • Correlation between topographic derivatives and SM varied with resolutions of DEMs. • UAV photogrammetry showed great potential for hydrological research. [ABSTRACT FROM AUTHOR]

Abstract Vegetation restoration was implemented to control soil erosion in the karst regions of southwest China. It is essential to assess the soil function and quality scientifically during this process and to adopt suitable management practices for this area. However, few studies have been conducted to comprehensively evaluate the effect of vegetation restoration on soil quality in this severely eroded karst area. By taking 302 soil samples from 11 vegetation types, this study investigated the influence of different types of vegetation restoration on soil quality using an integrated soil quality index (SQI) and a generalized linear model (GLM). Vegetation types had significant effects on soil properties and thus on soil quality. SQI was developed by using TN, TP, TK, AP, and clay content; TN had highest weighting values (0.58), which indicated that it contributed the most to final SQI. The highest and lowest SQI values were observed for primary forest and cropland, respectively. Overall, vegetation restoration (e.g., natural restoration, artificial forests and artificial grassland) improved soil quality significantly. A GLM model explained 73.20% of the total variation in SQI, and vegetation type explained the largest proportion (46.39%) of the variation, which implies that the vegetation restoration practices can greatly enhance the soil quality in karst landscapes of southwest China. The results of this study may be used to improve implication of ecological restoration and management in degraded regions. Graphical abstract Unlabelled Image Highlights • TN, TP, TK, AP, and clay content were representative indicators for soil quality index (SQI). • SQI of any vegetation restoration type was significantly greater than that of cropland. • Vegetation type is the dominant factor influencing SQI. [ABSTRACT FROM AUTHOR]

Southwest China, as one of the largest continuous karst areas in the world, is a severely eroded region due to its special geological condition. Thus, soil and water conservation measures such as dam construction have been extensively implemented in this region to control sediment delivery. However, it remains unclear how dam construction affects multiscale variability of sediment discharge (SD) and its potentially influential factors in southwest China. To assess this, annual SD, water discharge (WD), precipitation (PT), potential evapotranspiration (PET), and normalized differential vegetation index (NDVI) data from 1955 to 2015 were obtained from two karst watersheds of Liujiang (no large dams) and Hongshui (dam-controlled). These sites shared the similar climatic conditions. The Mann-Kendal test, Wilcoxon rank-sum test, and continuous wavelet transform analysis was used to detect the trends and periodicity in SD, and wavelet coherence analysis were employed to detect the temporal covariance between SD and WD, PT, PET, and NDVI. Results indicated that the multiscale variability of SD was strongly influenced by dam construction. The annual SD showed significant 4-year periodic oscillation in the Liujiang watershed, while no significant cycles were found in the Hongshui watershed. Dam construction exerted substantial influence on the multiscale correlations between SD and its associated factors. The time scales that the NDVI resonated with SD were concentrated on the periodicity of 2- and 3-year in the Liujiang watershed. In contrast, no significant periodicities were observed in the Hongshu watershed. This study yields a greater understanding of SD dynamics, and is helpful for better watershed management in karst areas of southwest China. [ABSTRACT FROM AUTHOR]

Karst landforms cover 7%-12% of the Earth's continental area and provide water resources for 25% of the global population. Climate, particularly frequent climate extremes, may greatly affect the annual runoff, especially in climate-sensitive regions such as a karst area of southwest China. Knowledge of the linkage between climate and runoff is urgently needed for smart water resources management. This study therefore selected five catchments that have different carbonized rock coverage (from 11% to 64%) to detect the dominant climatic variables driving changes in annual runoff for the period of 1957-2011 in southwest China. Because climatic variables are highly codependent, a partial least squares regression (PLSR) was used to elucidate the linkages between runoff and 17 climatic variables. Results indicated that the dominant climatic factors driving annual runoff are annual total precipitation, rainy days, heavy precipitation amount, heavy precipitation days, rainstorm amount, and rainstorm days. These six factors are generally used to represent extreme climatic events, and hence it may demonstrate that annual runoff is highly linked to precipitation extremes in this region. The PLSR approach presented in this study is beneficial and novel, as it enables the elimination of codependency among the variables and facilitates a more unbiased view of the contribution of the changes in climatic variables to the changes in runoff. As a practical and simple tool, the PLSR approach is thus recommended for application to a variety of other catchments. [ABSTRACT FROM AUTHOR]

Carbon and water cycles in forest ecosystems are tightly coupled, but global warming-induced soil and atmospheric droughts alter the coupling, thereby greatly increasing uncertainty in predicting carbon and water cycles. Therefore, a carbon–water coupled model (TRIPLEX-CW-Flux) was developed, and an R package (rTRIPLEXCWFlux) was created to facilitate model application. TRIPLEX-CW-Flux integrates vapor pressure deficit and soil moisture into a stomatal conductance submodule to estimate forest carbon and water fluxes. Prediction accuracy of TRIPLEX-CW-Flux and rTRIPLEXCWFlux application were evaluated in a Chinese fir (Cunninghamia lanceolata) plantation. Simulated net ecosystem production (NEP) and evapotranspiration (ET) were in good agreement with flux observations (R 2 : 0.76 for NEP ; 0.71 for ET). Thus, the TRIPLEX-CW-Flux model can be used to predict and quantify effects of global warming-induced droughts on forest carbon and water cycles. The open-access rTRIPLEXCWFlux package facilitates estimations of carbon sequestration and water consumption in forest ecosystems using the observed flux data. • A physiological process model that couples carbon and water flux was developed. • Both atmospheric and soil drought stress were also integrated into the model. • An R package was encoded for the model to predict forest carbon and water flux. • The simulated values were comparable to the flux data observed in the forest. • This R package can be used to evaluate forest functions under climate change. [ABSTRACT FROM AUTHOR]

• GPP and ET were positively and linearly correlated to Rn and VPD in a karst forest. • WUE was negatively correlated to meteorological factors but positively to Bowen ratio. • WUE was not proportional to 1/VPD or 1/VPD0.5 but interactively responded to drivers. Water-use efficiency (WUE) is a key parameter that measures the balance between carbon gain and water loss in an ecosystem. Achieving better understanding of how WUE responds to environmental drivers is critical for revealing ecohydrological processes and mechanisms, and for biophysical modelling to investigate the interactions between vegetation and the changing environment. Karst landforms cover ∼10 % of the Earth's land surface; however, to date few studies have focused on the behaviours of WUE in karstic ecosystems. To fill these knowledge gaps, a two-year experiment was conducted to investigate the WUE and its drivers in a climax karst forest in southwestern China. Results showed that both the GPP (Gross Primary Production) and ET (evapotranspiration) showed exponential relationships to Ta (air temperature, P < 0.05), but linear relationships to Rn (net radiation, R 2 = 0.38 (GPP) and 0.78 (ET), P < 0.05) and VPD (water vapour pressure deficit, R 2 = 0.36 (GPP) and 0.28 (ET), P < 0.05), being quite different from those in other ecosystems. The reasons would be the different habits of the karstic plants, and the facts that the root zone water availability rarely dropped to low levels due to the frequent precipitation. The WUE, with the mean of 8.0 ± 4.8 mg CO 2 g−1 H 2 O, exhibited negative relationships to VPD (R 2 = 0.23, P < 0.05), Rn (R 2 = 0.28, P < 0.05), and Ta (air temperature, R 2 = 0.42, P < 0.05), and a positive linear relationship to the Bowen ratio (R 2 = 0.17, P < 0.05). Besides these, results also showed that the effects of a specific driver (e.g., VPD) on WUE was affected obviously by other factors (e.g., Ta, Rn), indicating that whether a driver is important or not to WUE, depends strongly on the environmental conditions. As the WUE-response formulas are often used to investigate and model the interactions between vegetation and environment, these findings suggested that the modelers should caution the versatility of the WUE-response formulas. [ABSTRACT FROM AUTHOR]

Transferrin (Tf) is an important protein responsible for circulating and transporting iron into cytoplasm. Tf can be taken into cells through endocytosis mediated by Tf receptor, which usually overexpresses in cancer cells. The Tf-Tf receptor pathway opens a possible avenue for novel targeted cancer therapy by utilizing Tf-binding active compounds. Among which, anti-cancer active caffeoylquinic acids (CQAs) were recently found to be promising Tf-binders by our group. For better understanding the anti-cancer activities of CQAs, it is important to unveil the binding mechanisms between CQAs and Tf. In this study, the fluorescence quenching, surface plasmon resonance (SPR), circular dichroism (CD) and molecular docking were used to investigate the interactions between CQA and Tf. The results showed that the calculated apparent association constants of interactions between 1-, 3-, 4- and 5-CQA and Tf at 298 K were 7.97 × 10 5 M − 1 , 4.36 × 10 7 M − 1 , 6.58 × 10 5 M − 1 and 4.42 × 10 6 M − 1 , respectively. The thermodynamic parameters indicated that the interaction between 1-, 3-, 5-CQA and Tf is due to H-bonding, and electrostatic interactions were likely involved in the binding of 4-CQA and Tf. The CD results indicated that bindings of 1-CQA, 4-CQA and 5-CQA with Tf resulted in more stretched β-turn and random coil translated from β-sheet. In contrast, 3-CQA led to more stable a-helix conformation. Molecular docking studies of CQAs with Tf further displayed that CQAs were able to interact with residues near Fe 3 + binding site. The spectroscopic studies revealed the action mechanisms, thermodynamics and interacting forces between CQAs and Tf, and thus are helpful for future design and discovery of Tf-binders for targeted cancer therapy applying Tf-Tf receptor pathway. [ABSTRACT FROM AUTHOR]

Quantifying the impacts of climate and human activities on water and sediment discharge has become a central topic in climate and hydrologic research. This issue, however, has so far received little attention in karst regions around the world. Seven karst catchments located in southwest China were chosen to explore water and sediment discharge responses to different driving factors during the period from the 1950s to 2011. The non-parametric Mann-Kendall test was used to detect both the trends and abrupt changes in water and sediment discharge. The double mass curve method was used to quantify the effects of climate and human activities on water and sediment discharge. Results indicated that the annual water discharge showed a decreasing trend in all catchments (−0.21 to −3.68 × 10 8 m 3 yr −1 ), and the sediment discharge exhibited a significant decreasing trend (−7 to −101 × 10 4 t yr −1 ) for six out of the seven catchments. A rapid decline (abrupt change) in sediment discharge occurred since 2000 for all except Liujiang catchment where the sediment discharge has a slight increase since 1983 as no large dams were constructed in this catchment. Specifically, the magnitude of reduction in sediment discharge (%) significantly increases with the extent of flow regulation as measured by the ratio of the area upstream the dam to the total catchment area for the seven catchments ( R 2 = 0.98, P < 0.01). This study demonstrated that water discharge was mainly influenced by precipitation, while sediment discharge was mainly influenced by human activities (relative contribution 70–111%, regardless of whether the effect is negative or positive). Ecological restoration played somehow important roles in the decrease in sediment discharge (negative relationships of sediment discharge with the Normalized Differential Vegetation Index (NDVI)), but dam construction was likely to be the principal cause of the significant decrease in sediment discharge. This study is of use for better catchment management in karst regions in southwest of China. [ABSTRACT FROM AUTHOR]

Fufang Banbianlian Injection (FBI) has been widely used as an anti-inflammatory and anti-tumor prescription. To understand the relationships between its bioactive ingredients and pharmacological efficacies, our previous study has been successfully identified some DNA-binding compounds in FBI using an established on-line screening system, in which 4′,6-diamidino-2-phenylindole (DAPI) was developed as a probe. However, DAPI can be only used to screen ATT-specific DNA minor groove binders, leaving the potential active intercalators unknown in FBI. As a continuation of our studies on FBI, here we present a sensitive analytical method for rapid identification and evaluation of DNA-intercalators using propidium iodide (PI) as a fluorescent probe. We have firstly established the technique of high-performance liquid chromatography−diode-array detector−multistage mass spectrometry−deoxyribonucleic acid−propidium iodide−fluorescence detector (HPLC−DAD−MS n −DNA−PI−FLD) system. As a result, 38 of 58 previously identified compounds in FBI were DNA-intercalation active. Interestingly, all previously reported DNA-binders also showed intercalative activities, suggesting they are dual-mode DNA-binders. Quantitative study showed that flavonoid glycosides and chlorogenic acids were the main active compounds in FBI, and displayed similar DNA-binding ability using either DAPI or PI. In addition, 13 active compounds were used to establish the structure-activity relationships. In this study, PI was developed into an on-line method for identifying DNA-intercalators for the first time, and thus it will be a useful high-throughput screening technique for other related samples. [ABSTRACT FROM AUTHOR]

An on-line high-performance liquid chromatography−diode-array detector−electrospray ionization−ion-trap−time-of-flight−mass spectrometry−total antioxidant capacity detection (HPLC−DAD−ESI−IT−TOF−MS−TACD) system was created for identification and evaluation of antioxidants in Prunus ( P. ) mume flowers. Applying this system, the HPLC fingerprint, ultraviolet (UV) spectra, mass fragmentations, active profiles against 1,1-diphenylpicryl-2-hydrazyl radical (DPPH•) scavenging activity and ferric reducing antioxidant power (FRAP) of each complex sample were obtained simultaneously after one injection. Synchronous structure identification and activities screening of complex samples were thus accomplished. In this study, 78 compounds were identified from P. mume flowers by their chromatographic behaviors, UV spectra and MS data with the assistance of standard compounds and literature reports. The DPPH and FRAP activity of 24 samples (23 different P. mume varieties and 1 related herbal medicine) were then quantified by their detailed activity profiles from the on-line system, and by the total activity of each sample extract from off-line 96-well plate method. As a result, 21 and 32 compounds in the on-line system showed anti-oxidative effects against DPPH and FRAP, respectively. The established on-line system is efficient, sensitive and reliable to tell the DPPH and FRAP antioxidant activities of individual compound in complex samples, and therefore would be a useful and promising technique for antioxidant screening from different food and medicinal matrices. [ABSTRACT FROM AUTHOR]

Knowledge of vegetation water depletion and the underlying mechanisms are essential for understanding eco-hydrological processes and fragile ecological environment protection. Based on a 2-year field experiments, this study investigated the transpiration and its influencing factors for three karstic climax forest communities located in the depression (DeC), mid-slope (MsC) and summit (SuC) of a typical karst hill in southwestern China. The meteorological factors, sap-flow, eddy covariance and soil moisture were measured. Results showed that the annual transpiration for SuC, MsC and DeC, were 701.0 mm yr−1, 626.4 mm yr−1 and 663.1 mm yr−1, respectively. The daily transpiration was significantly correlated to the air temperature (r > 0.6, P < 0.05), solar radiation (r > 0.8, P < 0.05) and water vapor pressure deficit (r > 0.3, P < 0.05), but showed no strong relationship with the shallow layer water content (SLWC, 0–40 cm). Moreover, the transpiration of the three communities generally maintained high rate (e.g., > 4.0 mm d−1 in the growing seasons), even when the SLWC dropped to about 0.15 cm3 cm−3 in the SuC during dry spells. Overall, 77.6%, 78.3% and 90.8% of the transpired water in the SuC, MsC and DeC respectively, came from the shallow layer. These suggested that the plants in this region could uptake water from deep layers when the SLWC is limited, and implied that the climax forest communities were generally not limited by water, at least in normal years. • Transpiration of karstic climax forest (KCF) was mainly affected by meteorology. • Most of the water transpired by KCF came from the shallow layer (0–40 cm). • KCF also maintain high transpiration even during dry spells. • KCF should use deeper sources when water in shallow layer is limited. [ABSTRACT FROM AUTHOR]

The successful hydrogenation of azobenzene on NaNbO 3 is inseparable with the trans -to- cis isomerisation under UV light irradiation. The moderate activation of N N bond in cis azobenzene on Nb site makes its hydrogenation reaction proceed smoothly. The 100 % selectivity towards hydrazobenzene over the surface of NaNbO 3 can be attributed to the weak interaction between NaNbO 3 and N N bond in hydrazobenzene. • The hydrogenation of azobenzene on NaNbO 3 was inseparable with azobenzene isomerisation under UV light irradiation. • The contribution from the cis -azobenzene isomer accounted for more than 70% in the hydrogenation process. • The weak interaction between NaNbO 3 and hydrazobenzene should be the root cause to avoid over reduction. NaNbO 3 fibre catalyst can efficiently hydrogenate azobenzene to hydrazobenzene with 100 % selectivity under Xe light irradiation. The catalytic activity was closely dependent on the trans - cis photoisomerisation of azobenzene and the subsequent moderate activation of cis N N bond on Nb site. The adsorption of azobenzene with cis or trans conformation on the Nb active site was investigated by the computational methods. The apparent increase of the cis N N bond length from 1.254 to 1.348 Å, suggested an effective activation. The important role of the cis isomer in the reaction was also reflected in the quenching experiment, in which a silver quencher was used to inhibit the generation of the cis isomer. The weak interaction between Nb site and N N of hydrazobenzene was the key to inhibit the over reduction, which was confirmed by the in situ diffuse-reflectance IR spectra. [ABSTRACT FROM AUTHOR]