From Molecular Simulations to Experiments: The Recent Development of Room Temperature Ionic Liquid-Based Electrolytes in Electric Double-Layer Capacitors.

Due to the unique properties of room temperature ionic liquids (RTILs), most researchers' interest in RTIL-based electrolytes in electric double-layer capacitors (EDLCs) stems from molecular simulations, which are different from experimental scientific research fields. The knowledge of RTIL-based electrolytes in EDLCs began with a supposition obtained from the results of molecular simulations of molten salts. Furthermore, experiments and simulations were promoted and developed rapidly on this topic. In some instances, the achievements of molecular simulations are ahead of even those obtained from experiments in quantity and quality. Molecular simulations offer more information on the impacts of overscreening, quasicrowding, crowding, and underscreening for RTIL-based electrolytes than experimental studies, which can be helpful in understanding the mechanisms of EDLCs. With the advancement of experimental technology, these effects have been verified by experiments. The simulation prediction of the capacitance curve was in good agreement with the experiment for pure RTILs. For complex systems, such as RTIL-solvent mixtures and RTIL mixture systems, both molecular simulations and experiments have reported that the change in capacitance curves is not monotonous with RTIL concentrations. In addition, there are some phenomena that are difficult to explain in experiments and can be well explained through molecular simulations. Finally, experiments and molecular simulations have maintained synchronous developments in recent years, and this paper discusses their relationship and reflects on their application.

Rational design of MXene-based single atom catalysts for Na-Se batteries from sabatier principle.

Na-Se batteries have attracted great attention because of their high-energy density and low cost, though the shuttle effect of polyselenides and sluggish reaction dynamics still limit their practical applications. Herein, MXenes were decorated with single zinc atom as selenium hosts, and the effect of interfacial electrochemical reaction was studied via first-principles simulation. The embedding of single zinc atom into MXenes was found to enhance the anchoring ability to inhibit the shuttle effect. However, Zn-MXenes as single atom catalysts had different effects on interfacial electrochemical reactions, which can be attributed to the increased interaction strengths between Zn-MXenes and polyselenides. For Ti-based MXenes, the enhanced interaction was found to be beneficial for the electrochemical reaction, whereas the overly strong anchoring strength of Zn-Cr2CO2 would inhibit charging-discharging kinetics. Therefore, the matching of MXenes and metal atoms should be considered to adjust the anchoring ability based on the Sabatier principle. This work provides new insights into the design of SACs and high-performance Na-Se batteries.

Ti2CT2 MXene as Anodes for Metal Ion Batteries: From Monolayer to Bilayer to Pillar Structure.

The electrochemical performances of Ti2CT2 (T = F, O, and OH) MXenes with different layer structures (monolayer, bilayer, and pillared structures) as anodes for mono-/multivalent metal ion (Li+, Na+, Mg2+, and Al3+) batteries (MIBs) were studied via first-principles simulations. First, metal ions (MIs) adsorbed on Ti2CT2 monolayers were investigated to reveal the influence of MXene terminated groups on MIB performance. This indicated that O-terminated MXenes would be more suitable as electrodes. In particular, the theoretical capacity of Mg2+ on a Ti2CO2 monolayer could be more than 1500 mA h g-1. Then, MIs intercalated into MXene bilayers were considered to better understand the charging/discharging mechanism. In a Ti2CO2 bilayer with larger interlayer spacing, monovalent MIs and Mg2+ could form a multilayer accompanied by drastic expansion/contraction of the electrode, which still needs to be solved. Finally, imidazolium-based ionic liquids were used to preintercalate into MXene due to the matching size of the imidazolium cation, which effectively improved MXene stability and inhibited the self-stacking of layered MXenes. Our research would be helpful for theoretically regulating MXene functional groups and adjusting the interlayer spacing of MXenes via selecting guest molecules for designing MIBs and other energy storage devices.

Construction and Sensing Amplification of Raspberry-Shaped MOF@MOF.

MOFs@MOFs (metal-organic frameworks, MOFs) possess precise customized functionalities and predesigned structures that enable the implementation of structure and property regulation for specific functions in comparison to traditional single MOFs. However, the synthesis and fluorescence properties of multilayer MOFs@MOFs are still worth improving. Herein, a fluorescent raspberry-shaped MOF@MOF was constructed via optimized seed-mediated synthesis by tuning the reaction time, reaction mode, and reaction concentration, involving the initial synthesis of the UiO-66-NH2 core and then the coating of the UiO-67-bpy shell. The raspberry-shaped UiO-66@67-bpy showed stable fluorescence and desirable sensing selectivity for the Hg2+ ion under the interference of other ions; meanwhile, the raspberry-shaped UiO-66@67-bpy indicated amplified sensing performance than pure UiO-66-NH2, mechanically mixed UiO-66-NH2 + UiO-67-bpy, and UiO-66@UiO-67 counterpart due to the accumulation effect of outer UiO-67-bpy toward Hg2+. Density functional theory (DFT) calculations including adsorption energy calculations and electronic density difference analysis further showed that the enhanced fluorescence quenching was possibly attributed to the outer UiO-67-bpy enrichment promoting the charge transfer between Hg2+ and the ligands of fluorescent UiO-66@67-bpy. The synergistic effect of MOFs@MOFs unlocks more possibilities for the construction of enhanced sensors and other applications.

Quantum transport of short-gate MOSFETs based on monolayer MoSi2N4.

The high carrier mobility, appropriate band gap and good environmental stability of two-dimensional (2D) MoSi2N4 enable it to be an appropriate channel material for transistors with excellent performance. Therefore, we predict the performance of double-gate (DG) metal-oxide-semiconductor field-effect transistors (MOSFETs) based on monolayer (ML) MoSi2N4 by ab initio quantum-transport calculations. The results show that the on-state current of the p-type device is remarkable when the gate length is greater than 4 nm, which can meet the high performance requirements of the International Technology Roadmap for Semiconductors (ITRS), 2013 version. Moreover, the gate length can be reduced to 3 nm when an underlap (UL) structure is employed in the MOSFET, and the sub-threshold swing, intrinsic delay time and power consumption also perform well. The calculation results reveal that ML MoSi2N4 will be a promising alternative for transistor channel materials in the post-silicon era.

[Values of neutrophil-lymphocyte ratio and platelet-lymphocyte ratio in predicting sensitivity to intravenous immunoglobulin in Kawasaki disease].

OBJECTIVE: To study the values of neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) in predicting the sensitivity to intravenous immunoglobulin (IVIG) in Kawasaki disease (KD). METHODS: A retrospective cohort study was conducted in 404 children with newly diagnosed KD. The data on routine blood tests, NLR, and PLR were collected before and after IVIG treatment. The receiver operating characteristic (ROC) curve was used to determine the cut-off values of NLR and PLR in predicting the insensitivity to IVIG. A logistic regression analysis was used to identify independent predictive factors for insensitivity to IVIG. RESULTS: Of all patients, 31 were insensitive to IVIG. Compared with the IVIG sensitivity group, the IVIG insensitivity group had a significantly higher incidence rate of coronary artery ectasia (P<0.01), a shorter course of disease when IVIG therapy was initiated (P<0.05), and significantly higher NLR, PLR, and C-reactive protein (CRP) level before and after treatment (P<0.05). The optimal cut-off values for NLR and PLR to predict IVIG insensitivity were 4.36 and 162 before IVIG treatment and 1.45 and 196 after treatment. The multivariate regression analysis showed that the course of disease before IVIG treatment, CRP before IVIG treatment, and NLR and PLR before and after IVIG treatment were independent predictive factors for IVIG insensitivity. CONCLUSIONS: NLR and PLR can be used to predict IVIG insensitivity in children with KD.

Exclusive breastfeeding is inversely associated with risk of childhood overweight in a large Chinese cohort.

The association between breastfeeding status and childhood overweight is inconclusive. The aim of the present study was to investigate the relation between exclusive breastfeeding and childhood overweight risk in children 4-5 y of age in Southeast China. Among 97,424 children enrolled between 1999 and 2009 in the Jiaxing Birth Cohort, 42,550 of them were included in the final analysis with complete records on breastfeeding status and anthropometric measurements at 4-5 y of age (48-60 mo). Overweight and being at risk of overweight were identified as a body mass index (BMI)-for-age Z-score ≥ 2 and between 1 and 2, respectively. After 4-5 y of follow-up, 4845 (11.4%) children were identified as being at risk of overweight, and 1343 (3.16%) children were overweight. Adjusting for important child and maternal characteristics, longer duration of breastfeeding was associated with lower risk of childhood overweight (P-trend = 0.009) and being at risk of overweight (P-trend < 0.001). Children exclusively breastfed for 3-5 mo and ≥6 mo had 13% (RR = 0.87; 95% CI: 0.77, 0.99) and 27% (RR = 0.73; 95% CI: 0.56, 0.95) lower risk of becoming overweight compared with children exclusively breastfed for <1 mo, respectively. In boys, there were inverse associations of 3-5 mo (RR = 0.83; 95% CI: 0.71, 0.98) or ≥6 mo (RR = 0.65; 95% CI: 0.47, 0.91) of exclusive breastfeeding against becoming overweight, but there were no significant associations in girls (3-5 mo: RR = 0.96, 95% CI: 0.76, 1.22; ≥6 mo: RR = 0.92, 95% CI: 0.60, 1.41). In conclusion, the present findings suggest that longer duration of exclusive breastfeeding is associated with lower risk of becoming overweight in Chinese children.

Selection and evaluation of quality markers (Q-markers) of vladimiriae radix extract for cholestatic liver injury based on spectrum-effect relationship, pharmacokinetics, and molecular docking.

ETHNOPHARMACOLOGICAL RELEVANCE: As a representative local medicinal herb produced in China, Vladimiriae Radix (VR) has been proven to exert hepatoprotective and choleretic effects, with particular therapeutic efficacy in cholestatic liver injury (CLI), as demonstrated by the VR extract (VRE). However, the quality markers (Q-markers) of VRE for the treatment of CLI remain unclear. AIM OF THE STUDY: A new strategy based on the core element of "efficacy" was proposed, using a combination of spectrum-effect relationship, pharmacokinetics, and molecular docking methods to select and confirm Q-markers of VRE. MATERIAL AND METHODS: First, the HPLC fingerprinting of 10 batches of VRE was studied, and the in vivo pharmacological index of anti-CLI in rats was determined. The spectrum-effect relationship was utilized as a screening method to identify the Q-markers of VRE. Secondly, Q-markers were used as VRE pharmacokinetic markers to measure their concentrations in normal and CLI rat plasma, and to analyze their disposition. Finally, molecular docking was utilized to predict the potential interaction between the identified Q-markers and crucial targets of CLI. RESULTS: The fingerprints of 10 batches of VRE was established. The in vivo pharmacological evaluation of rats showed that VRE had a significant therapeutic effect on CLI. The spectrum-effect correlation analysis showed that costunolide (COS) and dehydrocostus lactone (DEH) were the Q-markers of VRE anti-CLI. The pharmacokinetic results showed that AUC(0-t), Cmax, CLZ/F, and VZ/F of COS and DEH in CLI rats had significant differences (P < 0.01). They were effectively absorbed into the blood plasma of CLI rats, ensuring ideal bioavailability, and confirming their role as Q-markers. Molecular docking results showed that COS, DEH had good affinity with key targets (FXR, CAR, PXR, MAPK, TGR5, NRF2) for CLI treatment (Binding energy < -4.52 kcal mol-1), further verifying the correctness of Q-marker selection. CONCLUSIONS: In this study, through the combination of experimental and theoretical approaches from the aspects of pharmacodynamic expression, in vivo process rules, and interaction force prediction, the therapeutic effect of VRE and Q-markers (COS、DEH) were elucidated. Furthermore, a new idea based on the principle of "efficacy" was successfully proposed for screening and evaluating Q-markers.

Ionic Liquids Microenvironment Modulates the Interface Properties of g-C3N4 for Boosting the Performance of Photodegradation and Infected Wound-Healing Therapy.

The improvement of photocatalytic activity of g-C3N4 is expected for its advanced applications but remains a challenge due to the limitations of current strategies, such as single function, inefficiency, and uneconomical. Herein, a modified g-C3N4 with improved interface properties is constructed through the modulation of the ionic microenvironment affected by ionic liquids (ILs) and exhibits a 2.3-fold enhanced photodegradation efficiency and a 3.5-fold enhanced reaction rate relative to pristine g-C3N4. It has demonstrated excellent performance in photo-therapy bacterial-infected wounds. Theoretical calculation indicated that the precursor can be regulated by designing the specific ILs microenvironment to form "ILs-Mel" clusters due to the diversity of interaction energy and electrostatic potential. The cluster results in uneven stress on the 2D plane, further inducing the reconstruction of the microstructure. The synergistic effect of cations and anions of ILs on regulating the interface properties of g-C3N4 due to the change of skeleton structure during thermolysis of ILs. The microstructure, surface, and optical-electrical properties can be adjusted by selecting different cations of ILs, and the custom-made band structure and wettability can be obtained by selecting different anions. This work provides a facile strategy to modulate the interface properties of g-C3N4 by building specific a microenvironment of precursor.

Comprehensive quality evaluation of two different geography originated Angelica sinensis Radix based on potential production area development and resource protection.

Angelica sinensis Radix (ASR) is mainly produced in the southern region of Gansu, China, and is a famous edible and medicinal herb. Noticeably, Aba region in Sichuan, China has similar geographical and climatic conditions to the southern region of Gansu, China, and has the potential to further develop the ASR planting industry chain. This study was the first to use an innovative method that combines GC-MS, HPLC-DAD fingerprints, and stoichiometric analysis to compare and explore the feasibility of using the Aba region as a source of high-quality ASR supplements. GC-MS analysis showed that the composition of ASR essential oil(AEO) in these two regions was highly similar (>99%). The HPLC data showed that the main sources of differences in ASR components between the two regions were coniferyl ferulate, E-ligustilide, Z-ligustilide, and Butylidenephthalide, which have great potential in anti-depression, regulating gut microbiota, and other aspects. The ASR in Aba region was rich in these components, and its biological activity might be higher to some extent than that in southern Gansu. This study confirmed the potential of the Aba region in Sichuan to become a high-quality production area for ASR, which was conducive to the expansion of ASR resources and the development of related industrial chains.

An effective method for preventing cholestatic liver injury of Aucklandiae Radix and Vladimiriae Radix: Inflammation suppression and regulate the expression of bile acid receptors.

ETHNOPHARMACOLOGICAL RELEVANCE: Aucklandiae Radix (AR) and Vladimiriae Radix (VR) were used to treat gastrointestinal, liver and gallbladder diseases at practice. In most conditions, VR was used to be a substitute of AR or a local habit may attribute to the same main active ingredients Costunolide and Dehydrocostus lactone, which presented many similar pharmacological activities. However, other different lactone compounds in AR and VR also play a role in disease treatment, so the difference in therapeutic effects of AR and VR in related diseases needs to be further studied. AIMS OF THE STUDY: Revealing the differences between the chemical compounds of the total lactone extracts of AR and VR (TLE of AR and VR) and the differences in the protective effects of cholestatic liver injury to ensure rational use of AR and VR. STUDY DESIGN AND METHODS: The macroporous adsorption resin was used to purify and enrich the lactone compounds to obtain the total lactone extracts of AR and VR. HPLC-PDA was used to obtain the data to establish chemical fingerprint and chemometric analysis to compare similarities and differences between TLE of AR and VR. The pharmacodynamic experiment revealed how TLE of AR and VR to show protect effects on cholestatic liver injury. RESULTS: Similarity analysis results showed TLE of AR and VR had a high similarity (>0.9). Nevertheless, difference analysis results showed 4 compounds, Costunolide, Dehydrocostus lactone, 3ß-acetoxy-11ß-guaia-4 (15), 10 (14)-diene-12,6α-olide and vladinol F may contribute to the differences between them. The pharmacodynamics experiments results showed the TLE of AR and VR affected the different liver cholate-associated transporters mRNA expression (TLE of AR up-regulated CYP7A1, TLE of VR down-regulated FXR and BSEP), the TLE of AR and VR had an effect to regulate biochemical indicators (AST, ALT, ALP, TBA) of liver function, and TLE of VR was better than TLE of AR in reducing the expression of inflammatory factors (IL-6 and IL-1ß). CONCLUSION: The liver protection of AR and VR have been confirmed, but the differences of material basis and mechanism of drug efficacy needed further study to guarantee formulation research and provide theoretical references for clinical rational applications of AR and VR.

Promising traditional Chinese medicine for the treatment of cholestatic liver disease process (cholestasis, hepatitis, liver fibrosis, liver cirrhosis).

ETHNOPHARMACOLOGICAL RELEVANCE: Cholestatic liver disease (CLD) is mainly characterized by cholestasis. If not treated, it will deteriorate to cholestatic hepatitis, liver fibrosis, liver cirrhosis, and even liver failure. CLD has a high clinical incidence, and limited treatment with single therapy. In the long-term clinical exploration, traditional Chinese medicine (TCM) has been corroborated with unique therapeutic effects on the CLD process. AIM OF THIS REVIEW: This paper summarizes the effective single and compound TCMs for the treatment of CLD. According to 4 important clinical stages of CLD: cholestasis, hepatitis, liver fibrosis, liver cirrhosis, pharmacological effects and mechanisms of 5 typical TCM examples are reviewed, aims to provide basis for clinical drug selection in different processes of CLD. MATERIALS AND METHODS: Relevant scientific articles regarding therapeutic effects of TCM for the CLD were collected from different databases. We collated three single herbs including Artemisia scoparia Waldst. et Kit. or Artemisia capillaris Thunb. (Artemisiae Scopariae Herba, Yin Chen in Chinese), Paeonia lactiflora Pall. or Paeonia veitchii Lynch. (Paeoniae radix rubra, Chi Shao in Chinese), Poria cocos (Schw.) Wolf (Poria, Fu Ling in Chinese), and two compound herbs of Huang Qi Decoction (HQD) and Yin Chen Hao Decoction (YCHD) to studied and analyzed. RESULTS: We proposed five promising TCMs treatments for the important developmental stages of CLD. Among them, Yin Chen is an essential medicine for protecting liver and gallbladder, and its TCM prescription is also a promising strategy for cholestasis. Based on clinical evidence, high-dose application of Chi Shao is a clinical special treatment of cholestasis hepatitis. Fu Ling can regulate immune cells and increase antibody levels in serum, which is expected to be an emerging therapy to prevent cholestatic liver fibrosis to cirrhosis. HQD can be used as routine clinical medicine for liver fibrosis. In addition, YCHD can exert better comprehensive advantages with multiple components, can treat the whole course of CLD and prevent it from developing to the end-stage. CONCLUSION: Yin Chen, Chi Shao, Fu Ling, HQD and YCHD have shown good clinical efficacy in controlling the development of CLD. Clinically, it is easier to curb the development of CLD by adopting graded diagnosis and treatment measures. We suggest that CLD should be risk stratified in clinical treatment to ensure personalized treatment for patients, so as to slow down the development of the disease.

Process optimization and characterization of arachidonic acid oil degumming using ultrasound-assisted enzymatic method.

Ultrasound assisted enzymatic method was applied to the degumming of arachidonic acid (ARA) oil produced by Mortierella alpina. The conditions of degumming process were optimized by response surface methodology with Box- Behnken design. A dephosphorization rate of 98.82% was achieved under optimum conditions of a 500 U/kg of Phospholipase A1 (PLA1) dosage, 2.8 mL/100 g of water volume, 120 min of ultrasonic time, and 135 W of ultrasonic power. The phosphorus content of ultrasonic assisted enzymatic degumming oil (UAEDO) was 4.79 mg/kg, which was significantly lower than that of enzymatic degumming oil (EDO, 17.98 mg/kg). Crude Oil (CO), EDO and UAEDO revealed the similar fatty acid compositions, and ARA was dominated (50.97 ~ 52.40%). The oxidation stability of UAEDO was equivalent to EDO and weaker than CO, while UAEDO presented the strongest thermal stability, followed by EDO and CO. Furthermore, aldehydes, acids and alcohols were identified the main volatile flavor components for the three oils. The proportions of major contributing components such as hexanal, nonanal, (E)-2-nonanal, (E, E)-2,4-decadienal, (E)-2-nonenal and aldehydes in UAEDO and EDO were all lower than CO. Overall, Ultrasound assisted enzymatic degumming proved to be an efficient and superior method for degumming of ARA oil.

Aucklandiae Radix and Vladimiriae Radix: A systematic review in ethnopharmacology, phytochemistry and pharmacology.

ETHNOPHARMACOLOGICAL RELEVANCE: Aucklandiae Radix (AR) and Vladimiriae Radix (VR), as commonly used traditional Chinese herbal medicine, were widely used in the treatment of gastrointestinal diseases. The two herbal medicines were warm, pungent and bitter. They entered the spleen, stomach, large intestine and gallbladder meridians, and had the effect of promoting qi circulation to relieve pain. It is usually used for chest and hypochondrium, abdominal fullness and pain, tenesmus, indigestion, and warming the middle to harmonize the stomach in clinically. AIM OF THIS REVIEW: To provide a reference for the identification of traditional use, the material basis of efficacy and preclinical research between AR and VR, this review systematically summarized the similarities and differences in ethnopharmacology, phytochemistry and modern pharmacology. MATERIALS AND METHODS: The literature information was collected systematically from the electronic scientific databases, including PubMed, Science Direct, Google Scholar, Web of Science, Geen Medical, China National Knowledge Infrastructure, as well as other literature sources, such as classic books of herbal medicine, master's thesis, doctoral thesis. RESULTS: In the plateau areas of Sichuan Province, VR used to be regarded as substitute or local habit for AR, which is regularly used for chest, abdominal fullness and pain, diarrhea, and other related diseases. In Chinese Pharmacopoeia (ChP) 2020 edition, 145 prescription preparations with AR were collected, such as Xianglian Wan, Muxiang Shunqi Wan, Liuwei Muxiang San. However, only one prescription preparation (Jiuxiang Zhitong Wan) contained VR. Additionally, 237 and 254 chemical components were separately isolated and identified from AR and VR, 69 kinds of compounds were common among them, and the significant differences were presented in sesquiterpene lactones, monoterpenoids, triterpenoids and phenylpropanoids. Moreover, Costunolide (COS) and Dehydrocostus lactone (DEH), two main research objects of modern pharmacology, showed multiple pharmacological activities. Not only could they inhibit the activity of some cancer cells (such as breast cancer and leukemia cells), but they regulated the levels of various inflammatory factors (including TNF-α, NF-κB, IL-1ß, IL-6) and repressed the growth and reproduction of various microorganisms (like Helicobacter pylori, Staphylococcus aureus). CONCLUSION: COS and DEH as the common active components, provide a certain basis for local medicine about the substitution of VR for AR in Sichuan province of China in the past. In addition, the sesquiterpenoids are the main common compounds in AR and VR by collecting and collating a large number of literature and various data websites. Furthermore, AR and VR have significant differences in ethnopharmacology and phytochemistry, especially in sesquiterpene lactones, monoterpenoids, triterpenoids and phenylpropanoids, and are probably viewed as reference of a separate list of AR and VR in Chinese Pharmacopoeia.

Acupoint herbal patching during Sanfu Days on reducing frequency of acute asthma attack in children: A systematic review and meta-analysis.

OBJECTIVE: Acupoint herbal patching (AHP) is an external therapy of Traditional Chinese Medicine. This systematic review and meta-analysis sought to evaluate whether AHP during Sanfu Days has additional benefits in children with asthma. METHODS: A comprehensively electronic literature search was performed in the Cochrane Library, PubMed, Embase, CNKI, VIP, and WanFang databases from their inception to March 2019. Randomized controlled trials that evaluated the AHP during Sanfu Days treatment for pediatric asthma were included. The main outcome measures were frequency of acute asthma attack, relapse of asthma, and pulmonary function. RESULTS: Eleven trials involving 882 children with asthma were identified. White mustard seed, rhizoma corydalis, and radix kansui were the most frequently used herbs. Adjunctive treatment with AHP significantly reduced the frequency of acute asthma attack (mean difference [MD] -1.62 times/year; 95% confidence intervals [CI] -2.13 to -1.11). Moreover, AHP improved the peak expiratory flow (standardized mean differences [SMD] 0.61; 95% CI 0.39-0.82) and forced expiratory volume in 1 s (SMD 0.48; 95% CI 0.31-0.66). CONCLUSIONS: Application of AHP during Sanfu Days has additional benefits in reducing the frequency of acute attack and improving pulmonary function in children with asthma. However, the current findings should be interpreted with caution owing to the methodological flaws of the analyzed trials.

Isotopic evidence for the shift of nitrate sources and active biological transformation on the western coast of Guangdong Province, South China.

Dual isotope nitrate (NO3-) analysis was performed on the western coast of Guangdong Province to investigate seasonal changes in the main nitrate sources and their biogeochemical processing, which are due to the rapid development of the local economy. In the nearshore area, significant seasonal variations of nitrate sources occurred. The dominant nitrate sources, originating from manure and sewage, suggested that the nitrate along the west coast of Guangdong Province was mainly influenced by local cities despite the westward flow of diluted Pearl River water. In the offshore area, the nitrate loss in the upper and mid water during both two seasons mainly caused by phytoplankton assimilation, whereas coupled nitrification-denitrification could be responsible for the nitrate loss in the bottom waters during summer. Our results suggest that, with the rapid development of local economy, the nitrate sources in the coastal area have shifted to manure and sewage from the local cities.

Spatial distribution of and historical changes in heavy metals in the surface seawater and sediments of the Beibu Gulf, China.

To study the impact of rapid industrialization and urbanization in Guangxi Province on the coastal environment in recent years, seven metals (Hg, Cu, Pb, Cd, Cr, Zn and As) were investigated in the surface seawater and sediments of the northern Beibu Gulf. The levels of the metals were lower than in other regions in China, but Hg, Cu and Cd showed a significant increasing trend in both seawater and sediments over the past 20 years. Higher levels were consistently observed in the nearshore area, particularly in the northwest, which may be related to the rapid industrial development in coastal areas. Correlation and principal component analyses suggested that both terrestrial inputs and biological processes influenced the distribution of metals. In addition, the higher risk observed for Hg and Cu may be largely influenced by the increasing trend in these metals in the Beibu Gulf.