Discovery of N-(phenylsulfonyl)thiazole-2-carboxamides as potent α-glucosidase inhibitors.

In a search for novel nonsugar α-glucosidase inhibitors for diabetes treatment, a series of N-(phenylsulfonyl)thiazole-2-carboxamide derivatives were designed and synthesized, the α-glucosidase inhibitory activities were then evaluated. Several compounds with promising α-glucosidase inhibitory effects were identified. Among these, compound W24 which shows low cytotoxicity and good α-glucosidase inhibitory activity with an IC50 value of 53.0 ± 7.7 µM, is more competitive compared with the commercially available drug acarbose (IC50 = 228.3 ± 9.2 µM). W24 was identified as a promising candidate in the development of α-glucosidase inhibitors. Molecular docking studies and molecular dynamics simulation were also performed to reveal the binding pattern of the active compound to α-glucosidase, and the binding free energy of the best compound W24 was 36.3403 ± 3.91 kcal/mol.

New Insight into CO2 Reduction to Formate by In Situ Hydrogen Produced from Hydrothermal Reactions with Iron.

To reveal the nature of CO2 reduction to formate with high efficiency by in situ hydrogen produced from hydrothermal reactions with iron, DFT calculations were used. A reaction pathway was proposed in which the formate was produced through the key intermediate species, namely iron hydride, produced in situ in the process of hydrogen gas production. In the in situ hydrogenation of CO2, the charge of H in the iron hydride was -0.135, and the Fe-H bond distance was approximately 1.537 Å. A C-H bond was formed as a transition state during the attack of Hδ- on Cδ+. Finally, a HCOO species was formed. The distance of the C-H bond was 1.107 Å. The calculated free energy barrier was 16.43 kcal/mol. This study may provide new insight into CO2 reduction to formate in hydrothermal reactions with metal.

Academician Wen-Rui Hu - Eminent Pioneer and Prominent Leader of Microgravity Science in China.

In 2021, the scientific community celebrated the 85th anniversary of the Chinese scientist Academician Wen-Rui Hu. In addition to his innovative contributions to cosmic magnetohydrodynamics (MHD) during his early scientific career, he has initiated microgravity science research in China from the middle of 1980s, and made many pioneering contributions to microgravity fluid physics. He has also promoted researches in China in the fields of space material science, space biotechnology, space fundamental physics, and relevant applications. He is respected as the founder of microgravity science in China because of his eminent pioneering contributions and prominent leadership. This article tries to provide a brief historical perspective of the tireless explorations of Academician Wen-Rui Hu in the field of microgravity science and other relevant disciplines till today based on personal views of his former students and colleagues.

Tiliroside induces ferroptosis to repress the development of triple-negative breast cancer cells.

Ferroptosis is a newly found form of non-apoptotic regulated cell death that is essential for the advancement of cancer. Tiliroside (Til), an effective natural flavonoid glycoside of oriental paperbush flower, has been explored as a potential anticancer agent in a few cancer types. However, it is unclear whether and how Til could promote the death of triple-negative breast cancer (TNBC) cells by inducing ferroptosis. Our study determined that Til induced cell death and attenuated cell proliferation in TNBC cells in vitro and in vivo with less toxicity for the first time. Functional assays showed that ferroptosis was the predominant form that contributed to Til-induced cell death of TNBC. Mechanistically, Til induces ferroptosis of TNBC cells via independent PUFA-PLS pathways but is closely involved in the Nrf2/HO-1 pathway. Silencing of HO-1 substantially abrogated the tumor-inhibiting effects of Til. In conclusion, our findings suggest that the natural product Til exerted its antitumor activity on TNBC by promoting ferroptosis, and the HO-1/SLC7A11 pathway plays an indispensable role in Til-induced ferroptotic cell death.

Design, synthesis and biological evaluation of novel 3-hydroxypyridin-4(1H)-ones based hybrids as Pseudomonas aeruginosa biofilm inhibitors.

Pseudomonas aeruginosa (P. aeruginosa) is a gram-negative pathogenic bacterium, often causative drug-resistance related human infections, given its great capacity to form bioflm. It uses three major quorum sensing (QS) systems, las, rhl, and pqs, to regulate the expression of genes related to virulence and biofilm formation. Consequently, strategies for inhibiting QS have garnered considerable attention as antimicrobial therapies. In this study, we designed and synthesized several 3-hydroxypyridin-4(1H)-one hybrids and assessed their potential as the inhibitors of P. aeruginosa biofilm formation. The most active compound identified was 12h; it exhibited satisfactory biofilm inhibitory activity (IC50: 10.59 ± 1.17 µM). Mechanistic studies revealed that 12h significantly inhibited the fluorescence of the PAO1-lasB-gfp and PAO1-pqsA-gfp fluorescent reporter strains and the production of Las-regulated (elastase) and Pqs-regulated (pyocyanin) virulence factors. These findings indicate that 12h inhibited biofilm formation by suppressing the expression of lasB and pqsA, thereby inactivating the las and pqs pathways. Furthermore, 12h improved the antibiotic susceptibility of P. aeruginosa and reduced the acute virulence of this bacterium in the African green monkey kidney cell line Vero. In conclusion, 3-hydroxypyridin-4(1H)-one hybrids, such as 12h, represent a promising class of antibacterial agents against P. aeruginosa.

Occurrence and ecological risk assessment of 16 phthalates in surface water of the mainstream of the Yangtze River, China.

Phthalic acid esters (PAEs), a class of typical endocrine disruptors, have received considerable attention due to their widespread applications and adverse effects on biological health. In this study, 30 water samples, along the mainstream of the Yangtze River (YR), were collected from Chongqing (upper stream) to Shanghai (estuary) from May to June in 2019. The total concentrations of 16 targeted PAEs ranged from 0.437 to 20.5 µg/L, with an average of 1.93 µg/L, where dibutyl phthalate (DBP, 0.222-20.2 µg/L), bis (2-ethylhexyl) phthalate (DEHP, 0.254-7.03 µg/L), and diisobutyl phthalate (DIBP, 0.0645-0.621 µg/L) were the most abundant PAEs. According to the pollution level in the YR to assess the ecological risk posed by PAEs, the results showed medium risk level of PAEs in the YR, among which DBP and DEHP posed a high ecological risk to aquatic organisms. The optimal solution for DBP and DEHP is found in ten fitting curves. The PNECSSD of them is 2.50 µg/L and 0.34 µg/L, respectively.

Novel Coumarin Derivatives Inhibit the Quorum Sensing System and Iron Homeostasis as Antibacterial Synergists against Pseudomonas aeruginosa.

Pseudomonas aeruginosa (P. aeruginosa) is well-known to cause biofilm-associated drug resistance and infections that often lead to treatment failure. Herein, we reported a dual-acting antibiofilm strategy by inhibiting both the bacterial quorum sensing system and the iron uptake system. A series of coumarin derivatives were synthesized and evaluated, and compound 4t was identified as the most effective biofilm inhibitor (IC50 = 3.6 µM). Further mechanistic studies have confirmed that 4t not only inhibits the QS systems but also competes strongly with pyoverdine as an iron chelator, causing an iron deficiency in P. aeruginosa. Additionally, 4t significantly improved the synergistic antibacterial effects of ciprofloxacin and tobramycin by more than 200-1000-fold compared to the single-dose antibiotic treatments. Therefore, our study has shown that 4t is a potentially novel antibacterial synergist candidate to treat bacterial infections.

Brucea javanica oil emulsion suppresses tumor growth in human cervical cancer cells through inhibition of the E6 oncogene and induction of apoptosis.

BACKGROUND: Brucea javanica oil emulsion (BJOE) is a traditional Chinese medicine with recognized antitumor effects in various cancers, but the effects and mechanisms of action of BJOE against cervical cancer need to be further studied. Herein, we investigated the effects of BJOE on the human papillomavirus (HPV)16-expressing human cervical cancer line SiHa and explored the possible underlying mechanisms. METHODS: Cell viability and apoptosis of SiHa cells treated with BJOE were assessed by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] and annexin V-fluorescein isothiocyanate (annexin V-FITC)/propidium iodide (PI) staining assays, respectively. Quantitative reverse transcription-polymerase chain reaction and Western blot analyses were performed to assess the expression levels of the E6 oncogene and key signaling molecules involved in apoptosis. A subcutaneous xenograft nude mouse model bearing SiHa cells was established and treated with BJOE through intraperitoneal injection. Tumor growth was monitored, and immunohistochemical analysis was performed. RESULTS: BJOE exhibited substantial cytotoxic effects in SiHa cells and significantly suppressed tumor growth in SiHa cell xenografts. BJOE inhibited E6 expression and induced apoptosis in vitro in a dose-dependent manner. BJOE-induced apoptosis was characterized by activation of caspase-3 and cleavage of poly(ADP-ribose) polymerase (PARP). Moreover, BJOE induced phosphorylation of extracellular-signal regulated kinase (ERK) and inhibited the expression of nuclear factor-kappa B (NF-κB). CONCLUSIONS: BJOE exerts a strong tumor-suppressive effect in SiHa cells in vitro and in vivo, likely caused by E6 inhibition and apoptosis induction achieved through the ERK/mitogen-activated protein kinase (MAPK) and NF-κB signaling pathways, supporting potential use of BJOE in cervical cancer treatment.

[Effect of acupuncture on patients with cancer-related fatigue and serum levels of CRP, IL-6, TNF-α and sTNF-R1].

OBJECTIVE: To observe the therapeutic effect of acupuncture on cancer-related fatigue (CRF) and to explore its possible mechanism. METHODS: A total of 80 patients with CRF were randomized into an observation group and a control group, and finally 67 patients completed the trial (36 patients in the observation group, 31 patients in the control group). Patients in the control group were treated with conventional chemoradiotherapy and symptomatic treatment, while no particular anti-fatigue intervention was adopted. On the basis of treatment in the control group, acupuncture was applied at Baihui (GV 20), Guanyuan (CV 4), Qihai (CV 6), Fengchi (GB 20), Zusanli (ST 36), Sanyinjiao (SP 6) in the observation group, once a day, 5 times as one course, with 2 days interval between each course, totally 4 courses were required. Before and after treatment, scores of functional assessment of cancer therapy-fatigue (FACT-F) in Chinese and McGill quality of life questionnaire (MQOL), serum levels of C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-α(TNF-α) and soluble TNF receptor-1 (sTNF-R1) were observed in the two groups. RESULTS: ①Compared before treatment, the FACT-F score was decreased after treatment in the observation group (P<0.05), while there was no significant difference in the control group (P<0.05). The change of the FACT-F score in the observation group was larger than that in the control group (P<0.05). ②In the observation group, scores of physiological and psychological dimension were decreased (P<0.05), score of social support dimension was increased after the treatment (P<0.05). The score changes of physiological, psychological and social support dimension in the observation group were larger than those in the control group (all P<0.05). ③After treatment, the serum levels of IL-6, TNF-α and sTNF-R1 were decreased in the observation group (P<0.05), while the serum levels of CPR and IL-6 were increased in the control group (P<0.05). The serum levels of CPR, IL-6 and TNF-α in the observation were lower than those in the control group (P<0.05). CONCLUSION: ①Acupuncture can improve the related symptoms of depression, weakness and headache in patients with CRF, strengthen their cognition of the support from society and family, and boost the confidence in curing the disease. ②Acupuncture can effectively down-regulate serum levels of the relative inflammatory factors, which may be its possible mechanism on treating CRF.

Parthenolide Augments the Chemosensitivity of Non-small-Cell Lung Cancer to Cisplatin via the PI3K/AKT Signaling Pathway.

The mortality rate of non-small-cell lung cancer (NSCLC) remains high worldwide. Although cisplatin-based chemotherapy may greatly enhance patient prognosis, chemotherapy resistance remains an obstacle to curing patients with NSCLC. Therefore, overcoming drug resistance is the main route to successful treatment, and combinatorial strategies may have considerable clinical value in this effort. In this study, we observed that both parthenolide (PTL) and cisplatin (DDP) inhibited the growth of NSCLC cells in a dose- and time-dependent manner. The combination of PTL and DDP presented a synergistic inhibitory effect on NSCLC at a ratio of 50:1. The combination of PTL and DDP synergistically inhibited cell migration and invasion, inhibited cell cycle progression, and induced apoptosis of A549 and PC9 cells. Bioinformatics and network pharmacology analysis indicated that PTL may primarily affect the phosphatidylinositol 3-kinase (PI3K)-AKT signaling pathway. After treatment with PTL and DDP either alone or in combination, Western blot analysis revealed that the proteins levels of Bax and cleaved Caspase-3 were upregulated, while p-PI3K, p-Akt, Caspase-3, and Bcl-2 proteins were downregulated. Among these alterations, the combination of PTL and DDP was found to exhibit the most significant effects. PTL might therefore be considered as a new option for combination therapy of NSCLC.

Direct Targeting of CREB1 with Imperatorin Inhibits TGFß2-ERK Signaling to Suppress Esophageal Cancer Metastasis.

Metastasis accounts for 90% of cancer death worldwide, and effective therapeutic strategies are lacking. The aim of this work is to identify the key drivers in tumor metastasis and screen therapeutics for treatment of esophageal squamous cell carcinoma (ESCC). Gene Ontology analysis of The Cancer Genome Atlas (TCGA) gene expression datasets of ESCC patients with or without lympy metastasis identifies that TGFß2 is highly enriched in the pathways essential for tumor metastasis and upregulates in the metastatic ESCC tumors. High TGFß2 expression in ESCC correlates with metastasis and patient survival, and functionally contributes to tumor metastasis via activating extracellular signal-regulated kinases (ERK) signaling. By screening of a library consisting of 429 bioactive compounds, imperatorin is verified as a novel TGFß2 inhibitor, with robustly suppressive effect on tumor metastasis in multiple mice models. Mechanistically, direct binding of imperatorin and CREB1 inhibits phosphorylation, nuclear translocation of CREB1, and its interaction with TGFß2 promoter, represses TGFß2 expression and fibroblasts-secreted CCL2, and then inactivates ERK signaling to block cancer invasion and abrogates the paracrine effects of fibroblasts on tumor angiogenesis and metastasis. Overall, the findings suggest the use of TGFß2 as a diagnostic and prognostic biomarker and therapeutic target in ESCC, and supports the potential of imperatorin as a novel therapeutic strategy for cancer metastasis.

Source apportionment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Huangpu River, Shanghai, China.

We applied cluster analysis and principal component analysis (PCA) with multivariate linear regression (MLR) to apportion sources of polycyclic aromatic hydrocarbons (PAHs) in surface sediments of the Huangpu River in Shanghai, China, based on the measured PAH concentrations of 32 samples collected at eight sites in four seasons in 2006. The results indicate that petrogenic and pyrogenic sources are the important sources of PAHs. Further analysis shows that the contributions of coal combustion, traffic-related pollution and spills of oil products (petrogenic) are 40%, 36% and 24% using PCA/MLR, respectively. Pyrogenic sources (coal combustion and traffic related pollution) contribute 76% of anthropogenic PAHs to sediments, which indicates that energy consumption is a predominant factor of PAH pollution in Shanghai. Rainfall, the monsoon and temperature play important roles in the distinct seasonal variation of PAH pollution, such that the contamination level of PAHs in spring is significantly higher than in the other seasons. BRIEF: We apportion PAHs in surface sediments of the Huangpu River and show that coal combustion, traffic-related pollution, and petroleum spillage are the major sources.

[Removal of Lead Ions from Water by Struvite Natural Zeolite Composite].

A nitrogen and phosphorus recovery product (NZ-MAP) containing struvite was applied to remove heavy metal ions and lead from water. NZ-MAP was characterized using XRD, FTIR, and SEM/EDS. The effects of dosage, initial pH, and reaction time on the removal process were investigated. The results show that the main component of NZ-MAP is a natural zeolite loaded with struvite. When the dosage is 0.4 g·L-1, the maximum adsorption amount is 749.74 mg·g-1, and the adsorption of Pb2+ in the solution increases first and then tends to reach a balance with increase of the pH. Its removal mechanism is mainly Pb10 (PO4)6 (OH)2 precipitation, and the effect is best when pH is 5.0. The removal process of Pb2+ from water is more in line with the quasi-two stage kinetic model. In an investigation of the effect of coexisting heavy metal ions on the removal of lead ions in water by NZ-MAP, it was found that coexisting Ni2+ and Cu2+ have little effect on NZ-MAP adsorption on Pb2+. Coexisting Zn2+ and Al3+ obviously inhibit the adsorption of Pb2+ by NZ-MAP. The research shows that NZ-MAP material can remove lead ions from water efficiently, thus offering an effective method for doing this.

Association of Chemoradiotherapy Regimens and Survival Among Patients With Nasopharyngeal Carcinoma: A Systematic Review and Meta-analysis.

Importance: The role of induction chemotherapy (IC) or adjuvant chemotherapy (AC) in the treatment of locoregionally advanced nasopharyngeal carcinoma (NPC) remains controversial. Objectives: To update meta-analyses on the association of survival outcomes with IC and AC regimens in patients with locoregionally advanced NPC and assess whether the current evidence is conclusive by a trial sequential analysis (TSA) approach. Data Sources: PubMed, Embase, and Web of Science were searched for articles published from inception until June 1, 2019. Study Selection: Randomized clinical trials that assessed the efficacy of radiotherapy with or without chemotherapy among previously untreated patients and patients with nondistant metastatic NPC. Data Extraction and Synthesis: Data were extracted by 2 investigators from each trial independently and synthesized by the 2 investigators. All trial results were combined and analyzed by a fixed- or random-effects model. Main Outcomes and Measures: Overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), and locoregional recurrence-free survival (LRFS). Results: A total of 8036 patients (median age, 46.5 years; 5872 [73.1%] male) from 28 randomized clinical trials were included in the analysis. Pooled analyses revealed that concurrent chemoradiotherapy (CCRT) was significantly associated with improved OS, PFS, DMFS, and LRFS compared with radiotherapy across all subgroups. The TSA confirmed the treatment outcomes of CCRT compared with radiotherapy. The additional IC regimen was associated with an improvement in OS (hazard ratio [HR], 0.84; 95% CI, 0.74-0.95), PFS (HR, 0.73; 95% CI, 0.64-0.84), DMFS (HR, 0.67; 95% CI, 0.59-0.78), and LRFS (HR, 0.74; 95% CI, 0.64-0.85). These findings were consistent in subgroup analyses of multicenter trials with sample sizes greater than 250, years of survival rate of 5 or greater, median follow-up longer than 5 years, or low risk of bias. However, the additional AC regimen was not associated with a survival benefit in OS (HR, 0.98; 95% CI, 0.78-1.23), PFS (HR, 0.86; 95% CI, 0.70-1.07), DMFS (HR, 0.84; 95% CI, 0.64-1.10), or LRFS (HR, 0.80, 95% CI, 0.59-1.09). The TSA provided sound evidence on the additional benefit of IC but not AC. Conclusions and Relevance: These data suggest a significant association of survival outcomes with CCRT in patients with locoregionally advanced NPC. The addition of IC instead of AC could achieve survival benefits. The potential therapeutic gain of AC should be explored in the future.

IGF2 induces CD133 expression in esophageal cancer cells to promote cancer stemness.

Failure to eradicate cancer stem cells (CSC) during primary therapy may lead to cancer recurrence. We recently reported that CD133 is a functional biomarker for CSCs in esophageal squamous cell carcinoma (ESCC) but the molecular pathways critical for maintenance of CD133-positive CSCs are largely unknown. Here, we revealed that knockdown of IGF2 or treatment with PI3K/AKT inhibitors markedly inhibited the abilities of CD133-positive ESCC cells to self-renew, resist chemotherapeutic drugs, and form tumors. Further functional analysis identified miR-377 as a downstream regulator of PI3K/AKT signaling, and a mediator of the effects of IGF2 on CD133 expression and CSC properties. We found that the expression levels of IGF2 and CD133 were positively correlated with each other in primary ESCC, and that concurrent elevation of IGF2 and CD133 expression was significantly associated with poor patient survival. Furthermore, in vivo experiments demonstrated that IGF2-neutralizing antibody enhanced the sensitivity of tumor xenografts in nude mice to 5-fluorouracil treatment. This study underpins the importance of the IGF2-PI3K/AKT-miR-377-CD133 signaling axis in the maintenance of cancer stemness and in the development of novel therapeutic strategy for treatment of esophageal cancer.

Binding of Sudan II and IV to lecithin liposomes and E. coli membranes: insights into the toxicity of hydrophobic azo dyes.

BACKGROUND: Sudan red compounds are hydrophobic azo dyes, still used as food additives in some countries. However, they have been shown to be unsafe, causing tumors in the liver and urinary bladder in rats. They have been classified as category 3 human carcinogens by the International Agency for Research on Cancer. A number of hypotheses that could explain the mechanism of carcinogenesis have been proposed for dyes similar to the Sudan red compounds. Traditionally, investigations of the membrane toxicity of organic substances have focused on hydrocarbons, e.g. polycyclic aromatic hydrocarbons (PAHs), and DDT. In contrast to hydrocarbons, Sudan red compounds contain azo and hydroxy groups, which can form hydrogen bonds with the polar head groups of membrane phospholipids. Thus, entry may be impeded. They could have different toxicities from other lipophilic hydrocarbons. The available data show that because these compounds are lipophilic, interactions with hydrophobic parts of the cell are important for their toxicity. Lipophilic compounds accumulate in the membrane, causing expansion of the membrane surface area, inhibition of primary ion pumps and increased proton permeability. RESULTS: This work investigated the interactions of the amphiphilic compounds Sudan II and IV with lecithin liposomes and live Escherichia coli (E. coli). Sudan II and IV binding to lecithin liposomes and live E. coli corresponds to the Langmuir adsorption isotherm. In the Sudan red compounds--lecithin liposome solutions, the binding ratio of Sudan II to lecithin is 1/31 and that of Sudan IV to 1/314. The binding constant of the Sudan II-lecithin complex is 1.75 x 104 and that of the Sudan IV-lecithin complex 2.92 x 105. Besides, the influences of pH, electrolyte and temperature were investigated and analyzed quantitatively. In the Sudan red compounds--E.coli mixture, the binding ratios of Sudan II and Sudan IV to E.coli membrane phospholipid are 1/29 and 1/114. The binding constants of the Sudan II--and Sudan IV- E.coli membrane phospholipid complexes are 1.86 x 104 and 6.02 x 104. Over 60% of Sudan II and 75% of Sudan IV penetrated into E.coli, in which 90% of them remained in the E.coli membrane. CONCLUSION: Experiments of Sudan II and IV binding to lecithin liposomes and live E. coli indicates that amphiphilic compounds may be sequestered in the lecithin liposomes and membrane phospholipid bilayer according to the Langmuir adsorption law. Penetration into the cytosol was impeded and inhibited for Sudan red compounds. It is possible for such compounds themselves (excluding their metabolites and by-products)not result directly in terminal toxicity. Therefore, membrane toxicity could be manifested as membrane blocking and membrane expansion. The method established here may be useful for evaluating the interaction of toxins with membranes.

Photochemical degradation of diethyl phthalate with UV/H2O2.

The decomposition of diethyl phthalate (DEP) in water using UV-H2O2 process was investigated in this paper. DEP cannot be effectively removed by UV radiation and H2O2 oxidation alone, while UV-H2O2 combination process proved to be effective and could degrade this compound completely. With initial concentration about 1.0mg/L, more than 98.6% of DEP can be removed at time of 60 min under intensity of UV radiation of 133.9 microW/cm2 and H2O2 dosage of 20mg/L. The effects of applied H2O2 dose, UV radiation intensity, water temperature and initial concentration of DEP on the degradation of DEP have been examined in this study. Degradation mechanisms of DEP with hydroxyl radicals oxidation also have been discussed. Removal rate of DEP was sensitive to the operational parameters. A simple kinetic model is proposed which confirms to pseudo-first order reaction. There is a linear relationship between rate constant k and UV intensity and H2O2 concentration.

Removal of cadmium using MnO2 loaded D301 resin.

MnO2 loaded weak basic anion exchange resin D301 (Anion exchange resin, macroreticular weak basic styrene) as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd2+ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. T he saturate adsorption capacity of the Cd2+ was 77.88 mg/g. Theadsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.

Particle size distribution and removal by a chemical-biological flocculation process.

The particle characterization from the influent and effluent of a chemical-biological flocculation (CBF) process was studied with a laser diffraction device. Water samples from a chemically enhanced primary treatment (CEPT) process and a primary sediment tank process were also analyzed for comparison. The results showed that CBF process was not only effective for both the big size particles and small size particles removal, but also the best particle removal process in the three processes of CBF process, CEPT process, and PST process (primary sediment tanks). The results also indicated that CBF process was superior to CEPT process in the heavy metals removal. The high and non-selective removal for heavy metals might be closely related to its strong ability to eliminate small particles. Samples from different locations in CBF reactors showed that small particles were easier to aggregate into big ones and those disrupted flocs could properly flocculate again along CBF reactor because of the biological flocculation.

[Separation of Cr( VI) and organic Cr(III) in natural water by weak basic anion exchange resin and determination by ICP-AES].

For the separation and determination of inorganic Cr(VI) and organic Cr(III) in natural water, a sensitive and selective method was developed using a weak basic anion exchange resin micro-column and inductively coupled plasma atomic emission spectrometry (ICP-AES). Under optimized conditions, organic Cr(III) and inorganic Cr( VI) were retained on the column, and eluted with 1. 0 mol x L(-1) HCl and 2. 0 mol x L(-1) NH4 NO3 +0. 5 mol x L(-1) NH3 x H2O respectively. Then the concentrations of Cr(VI) and organic Cr(III) were determined by ICP-AES. The detection limits of organic Cr( III ) and inorganic Cr(VI) were 1. 1 and 1. 4 microg x L(-1) , and relative standard deviations(RSD) were 3. 8% and 5. 6% respectively. The proposed method has been applied to the determination and separation of chromium in several practical water samples with a recovery between 90. 4% and 106. 3%.