PPP1r18 promotes tumor progression in esophageal squamous cell carcinoma by regulating the calcineurin-mediated ERK pathway.

Esophageal cancer is one of the most common malignant tumors, and the 5-year overall survival rate is only 20%. Esophageal squamous cell carcinoma (ESCC) is the primary histological type of esophageal carcinoma in China. Protein phosphatase 1 regulatory subunit 18 (PPP1r18) is one of the actin-regulatory proteins and is able to bind to protein phosphatase 1 catalytic subunit alpha (PPP1CA). Yet, little is known about the role of PPP1r18 in esophageal squamous cell carcinoma (ESCC). This study aimed to elucidate the biological functions of PPP1r18 in the ESCC progression. Clinical samples first confirmed that PPP1r18 expression was upregulated in ESCC, and PPP1r18 was correlated with tumor invasion depth, lymph node metastasis, distant metastasis, and reduced overall survival. We then observed that PPP1r18 overexpression enhanced cell proliferation in vitro and in vivo. Mechanistically, PPP1r18 regulated tumor progression of ESCC through activating the calcineurin-mediated ERK pathway, rather than binding to PPP1CA. Collectively, our results suggest that PPP1r18 promotes ESCC progression by regulating the calcineurin-mediated ERK pathway. PPP1r18 might be a potential target for the diagnosis and treatment of ESCC.

Telocytes protect against lung tissue fibrosis through hexokinase 2-dependent pathway by secreting hepatocyte growth factor.

Pulmonary fibrosis (PF) is one of the common manifestations of end-stage lung disease. Chronic lung failure after lung transplantation is mainly caused by bronchiolitis obliterans syndrome (BOS) and is mainly characterized by lung tissue fibrosis. Pulmonary epithelial-mesenchymal transformation (EMT) is crucial for pulmonary fibrosis. Telocytes (TCs), a new type of mesenchymal cells, play a protective role in various acute injuries. For exploring the anti-pulmonary fibrosis effect of TCs in the BOS model in vitro and the related mechanism, rat tracheal epithelial (RTE) cells were treated with transforming growth factor-ß (TGF-ß) to simulate lung tissue fibrosis in vitro. The RTE cells were then co-cultured with TCs primarily extracted from rat lung tissue. Western blot, Seahorse XF Analysers and enzyme-linked immunosorbent assay were used to detect the level of EMT and aerobic respiration of RTE cells. Furthermore, anti-hepatocyte growth factor (anti-HGF) antibody was exogenously added to the cultured cells to explore further mechanisms. Moreover, hexokinase 2 (HK2) in RTE cells was knocked down to assess whether it influences the blocking effect of the anti-HGF antibody. TGF-ß could induce lung tissue fibrosis in RTE cells in vitro. Nevertheless, TCs co-culture decreased the level of EMT, glucose metabolic indicators (lactate and ATP) and oxygen levels. Furthermore, TCs released hepatocyte growth factor (HGF). Therefore, the exogenous addition of anti-HGF antibody in the co-culture system blocked the anti-lung tissue fibrosis effect. However, HK2 knockdown attenuated the blocking effect of the anti-HGF antibody. In conclusion, TCs can protect against lung tissue fibrosis by releasing HGF, a process dependent on HK2.

Neoadjuvant adebrelimab in locally advanced resectable esophageal squamous cell carcinoma: a phase 1b trial.

Overall survival (OS) benefits of neoadjuvant immunotherapy remain elusive in locally advanced esophageal squamous cell carcinomas (ESCC). Here, we reported the results of a phase 1b trial of neoadjuvant PD-L1 blockade with adebrelimab in resectable ESCC. Patients received two neoadjuvant doses of adebrelimab followed by surgery. The primary endpoints were safety and feasibility; secondary endpoints included pathologic complete response (pCR) and OS. Our data showed the primary endpoints of safety and feasibility had been met. Common treatment-related adverse events were anorexia (32%) and fatigue (16%), without grade 3 or more adverse events. Of the 30 patients enrolled in the trial, 25 underwent successful resection without surgery delay and 24% had major pathologic responses including a pCR rate of 8%. The 2-year OS was 92%. Responsive patients had an immune-enriched tumor microenvironment phenotype, whereas nonresponsive patients had greater infiltration of cancer-associated fibroblasts at baseline. Clonotypic dynamics of pre-existing intratumoral T cells was a hallmark of responsive patients. These findings provide a rational for neoadjuvant anti-PD-L1 monotherapy as a therapeutic strategy for patients with resectable ESCC. ClinicalTrials.gov identifier: NCT04215471 .

Development and Validation of PET/CT-Based Nomogram for Preoperative Prediction of Lymph Node Status in Esophageal Squamous Cell Carcinoma.

PURPOSE: This study was conducted to predict the lymph node status and survival of esophageal squamous cell carcinoma before treatment by PET-CT-related parameters. METHODS: From January 2013 to July 2018, patients with pathologically diagnosed ESCC at our hospital were retrospectively enrolled. Completed esophagectomy and two- or three-field lymph node dissections were conducted. Those with neoadjuvant therapy were excluded. The first 65% of patients in each year were regarded as the training set and the last 35% as the test set. Nomogram was constructed by the "rms" package. Five-year, overall survival was analyzed based on the best cutoff value of risk score determined by the "survivalROC" package. RESULTS: Ultimately, 311 patients were included with 209 in the training set and 102 in the test set. The positive rate of the lymph node in the training set was 36.8% and that in the test set was 32.4%. The C-index of the training set was 0.763 and the test set was 0.766. The decision curve analysis showed that it was superior to the previous methods based on lymph node uptake or long/short axis diameter or axial ratio. Risk score > 0.20 was significantly associated with 5-year, overall survival (p = 0.0015) in all patients. CONCLUSIONS: The nomogram constructed from PET-CT parameters including primary tumor metabolic length and thickness can accurately predict the risk of lymph node metastasis in ESCC. The risk score calculated by our model accurately predicts the patient's 5-year overall survival.

Neoadjuvant therapy with immunoagent (nivolumab) or placebo plus chemotherapy followed by surgery and adjuvant treatment in subjects with resectable esophageal squamous cell carcinoma: study protocol of a randomized, multicenter, double blind, phase II trial (NATION-2203 trial).

Background: Neoadjuvant chemotherapy (nCT) has been the recommended treatment for locally advanced esophageal squamous cell carcinoma (ESCC). The addition of programmed cell death protein 1 (PD-1) inhibitor to nCT may improve oncologic outcome and survival. However, high-level evidence of neoadjuvant immunotherapy (nIT) combined with nCT in locally advanced resectable ESCC patients are still lacking. Hence, we describe this randomized controlled trial in order to assess the efficacy and safety of neoadjuvant nivolumab in combination with chemotherapy for locally advanced (stage II-III) ESCC patients. Methods: This prospective, randomized, multicenter phase II trial aims to enroll 90 locally advanced (stage II-III) ESCC patients who will undergo nivolumab or placebo plus chemotherapy followed by surgery. Patients will be 2:1 randomized to nivolumab/chemo and placebo/chemo group by method of stratified randomization. In both arms, patients who have not achieved complete pathological complete response (pCR) will be administered with adjuvant nivolumab for up to 1 year. The primary endpoint is pCR rate and secondary endpoints include event-free survival (EFS), R0 resection rate, and adverse events (AEs). The safety will be evaluated by AEs, grading by Common Terminology Criteria for Adverse Events (CTCAE) 5.0 classifications. The double-blind will be maintained between subjects and investigators until the final unblinding process. Discussion: This protocol has been reviewed and approved by the Ethics Committee of Zhongshan Hospital (B2022-004R). This is the first prospective, multicenter, randomized controlled trial to compare the combination of immunotherapy and chemotherapy with standard chemotherapy in neoadjuvant treatment for ESCC, also to explore whether adjuvant immunotherapy offers additional benefit in non-pCR patients after nCT with/without immunotherapy and R0 resection. We hypothesize that the pCR rate, R0 resection rate, EFS and OS of the study group (nivolumab/chemo) is significantly better than those of control group. Registration: ClinicalTrial.gov: NCT05213312.

Association of LAMA1 Single-Nucleotide Polymorphisms with Risk of Esophageal Squamous Cell Carcinoma among the Eastern Chinese Population.

Introduction: LAMA1, also known as laminin subunit α1, is a member of the laminin family, which is widely reported to be a key basement membrane molecule that affects various biological activities and is associated with many kinds of diseases. We aimed to investigate the association between LAMA1single-nucleotide polymorphisms and the occurrence and progression of esophageal squamous cell carcinoma in the Chinese population. Method: 2,186 participants were collected retrospectively between October 2008 and January 2017, including 1,043 ESCC patients and 1,143 noncancer patients. A 2 mL blood sample was obtained intravenously for the LDR for SNP analysis. The 6 SNP loci of LAMA1 were selected and examined. We analyzed the association of several genetic models of 6 LAMA1 SNP loci, sex, age, smoking and drinking status, and the occurrence of esophageal squamous cell carcinoma. Results: In the rs62081531 G > A locus, genotype GA was a protective factor for ESCC compared with GG (OR: 0.830, P=0.046), especially among the younger and nondrinkers. At rs607230 T > C, genotype TC was linked with a lower risk of ESCC compared with TT. (OR: 0.613, P=0.034). Haplotype Frequencies revealed that Ars62081531Grs621993Ars539713Trs566655Ars73938538Crs607230 (OR: 0.803, P=0.028) and Grs62081531Grs621993Ars539713Trs566655Crs73938538Crs607230 (OR: 0.679, P=0.010) were strongly associated with lower susceptibility of ESCC. Conclusion: The LAMA1 rs62081531, rs539713, rs566655, and rs607230 polymorphisms were demonstrated to be related to susceptibility to ESCC in the Chinese population. LAMA1 SNPs may have a significant impact on the occurrence of esophageal cancer and may serve as potential diagnostic biomarkers.

Fibroblast growth factor 10 attenuates chronic obstructive pulmonary disease by protecting against glycocalyx impairment and endothelial apoptosis.

BACKGROUND: The defects and imbalance in lung repair and structural maintenance contribute to the pathogenesis of chronic obstructive pulmonary diseases (COPD), yet the molecular mechanisms that regulate lung repair process are so far incompletely understood. We hypothesized that cigarette smoking causes glycocalyx impairment and endothelial apoptosis in COPD, which could be repaired by the stimulation of fibroblast growth factor 10 (FGF10)/FGF receptor 1 (FGFR1) signaling. METHODS: We used immunostaining (immunohistochemical [IHC] and immunofluorescence [IF]) and enzyme-linked immunosorbent assay (ELISA) to detect the levels of glycocalyx components and endothelial apoptosis in animal models and in patients with COPD. We used the murine emphysema model and in vitro studies to determine the protective and reparative role of FGF10/FGFR1. RESULTS: Exposure to cigarette smoke caused endothelial glycocalyx impairment and emphysematous changes in murine models and human specimens. Pretreatment of FGF10 attenuated the development of emphysema and the shedding of glycocalyx components induced by CSE in vivo. However, FGF10 did not attenuate the emphysema induced by endothelial-specific killing peptide CGSPGWVRC-GG-D(KLAKLAK)2. Mechanistically, FGF10 alleviated smoke-induced endothelial apoptosis and glycocalyx repair through FGFR1/ERK/SOX9/HS6ST1 signaling in vitro. FGF10 was shown to repair pulmonary glycocalyx injury and endothelial apoptosis, and attenuate smoke-induced COPD through FGFR1 signaling. CONCLUSIONS: Our results suggest that FGF10 may serve as a potential therapeutic strategy against COPD via endothelial repair and glycocalyx reconstitution.

The Single Nucleotide Polymorphisms of AP1S1 are Associated with Risk of Esophageal Squamous Cell Carcinoma in Chinese Population.

Background: The σ1A subunit of the adaptor protein 1 (AP1S1) participates in various intracellular transport pathways, especially the maintenance of copper homeostasis, which is pivotal in carcinogenesis. It is therefore rational to presume that AP1S1 might also be involved in carcinogenesis. In this hospital-based case-control study, we investigated the genetic susceptibility to ESCC in relation to SNPs of AP1S1 among Chinese population. Methods: A database containing a total of 1303 controls and 1043 ESCC patients were retrospectively studied. The AP1S1 SNPs were analyzed based on ligation detection reaction (LDR) method. Then, the relationship between ESCC and SNPs of AP1S1 was determined with a significant crude P<0.05. Then the logistic regression analysis was used for the calculation for adjusted P in the demographic stratification comparison if a significant difference was observed in the previous step. Results: AP1S1 rs77387752 C>T genotype TT was an independent risk factor for ESCC, while rs4729666 C>T genotype TC and rs35208462 C>T genotype TC were associated with a lower risk for ESCC, especially in co-dominant model and allelic test for younger, male subjects who are not alcohol-drinkers nor cigarette smokers. Conclusion: AP1S1 rs77387752, rs4729666 and rs35208462 polymorphisms are associated with susceptibility to ESCC in Chinese individuals. AP1S1 SNPs may exert an important role in esophageal carcinogenesis and could serve as potential diagnostic biomarkers.

Which will carry more weight when CTR > 0.5, solid component size, CTR, tumor size or SUVmax?

BACKGROUND: This study was conducted to explore the clinical significance of the maximum standard uptake value (SUVmax) in the clinical stage IA lung adenocarcinoma with tumor size ≤ 2 cm and consolidation to tumor ratio (CTR) > 0.5. METHODS: We retrospectively reviewed non-small cell lung cancer patients who underwent surgeries between January 2014 and March 2017. Clinical stage IA lung adenocarcinoma patients with tumor of size ≤ 2 cm and CTR > 0.5 were enrolled. The patients were divided into two groups: part-solid and pure-solid based on whether CTR = 1.0 or not. Nodules with any amount of solid or micropapillary components were regarded as the high-risk subtype. Time-dependent ROC curve was used to determine the best cut-off value. Finally, we analyzed the relationship between SUVmax, high-risk subtypes, node metastasis and 5-year relapse-free survival and overall survival. RESULTS: Totally, 270 patients were included. The distribution of pathological subtypes (p < 0.001), SUVmax (p < 0.001), and pathological N stage (p < 0.001) were different between the two groups. Multivariable analysis indicated that SUVmax could predict high-risk subtypes in cases of part-solid nodules (p < 0.001) and both high-risk subtypes (p = 0.022) and node metastasis (p < 0.001) in cases of pure-solid ones. SUVmax ≥ 2.6 and SUVmax ≥ 5.1 were strongly associated with 5-year relapse-free survival (p < 0.001) and 5-year overall survival (p < 0.001) among all the patients, respectively. CONCLUSION: Part-solid nodules with 0.5 < CTR < 1 and pure-solid nodules in lung adenocarcinoma show different clinicopathological characteristics, especially in SUVmax. SUVmax is significantly associated with high-risk subtypes, node metastasis, 5-year relapse-free survival and overall survival.

Enhanced Oral Bioavailability of Pueraria Flavones by a Novel Solid Self-microemulsifying Drug Delivery System (SMEDDS) Dropping Pills.

To improve bioavailability of pueraria flavones (PF), a self-microemulsifying drug delivery system (SMEDDS) dropping pills composed of PF, Crodamol GTCC, Maisine 35-1, Cremophor RH 40, 1,2-propylene glycol and polyethylene glycol 6000 (PEG6000) was developed. Particle size, zeta potential, morphology and in vitro drug release were investigated, respectively. Pharmacokinetics, bioavailability of PF-SMEDDS dropping pills and commercial Yufengningxin dropping pills were also evaluated and compared in rats. Puerarin treated as the representative component of PF was analyzed. Dynamic light scattering showed the ability of PF-SMEDDS dropping pills to form a nanoemulsion droplet size in aqueous media. The type of media showed no significant effects on the release rate of PF. PF-SMEDDS dropping pills were able to improve the in vitro release rate of PF, and the in vitro release of these dropping pills was significantly faster than that of Yufengningxin dropping pills. There was a dramatic difference between the mean value of t1/2, peak concentration (Cmax), the area of concentration-time curve from 0 to 6 h (AUC0-6 h) of PF-SMEDDS dropping pills and that of commercial Yufengningxin dropping pills. A pharmacokinetic study showed that the bioavailability of PF was greatly enhanced by PF-SMEDDS dropping pills. The value of Cmax and relative bioavailability of PF-SMEDDS dropping pills were dramatically improved by an average of 1.69- and 2.36-fold compared with that of Yufengningxin dropping pills after gavage administration, respectively. It was concluded that bioavailability of PF was greatly improved and that PF-SMEDDS dropping pills might be an encouraging strategy to enhance the oral bioavailability of PF.

Endocrine disrupting chemicals in New Orleans surface waters and Mississippi Sound sediments.

Endocrine disrupting compounds (EDCs), represented by steroid hormones, organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and bisphenol A have been determined in four sediment cores from the Gulf of Mexico, from New Orleans surface water (Lake Pontchartrain and Mississippi River), and from the influent and effluent of a New Orleans municipal sewage treatment plant. During the five-month monitoring of selected EDCs in the Mississippi River (MR) and Lake Pontchartrain (LP) in 2008, 21 of 29 OCPs in MR and 17 of 29 OCPs in LP were detected; bisphenol A was detected in all of the samples. Steroid hormones (estrone, 17ß-estradiol and 17α-ethinylestradiol) were detected occasionally. Total EDC (OCPs + PCBs + steroid hormones + bisphenol A) concentrations in the two surface water samples were found to vary from 148 to 1112 ng L(-1). Strong correlation of the distribution of total OCPs, total PCBs and total EDCs between solid and water phases was found in LP, while moderate or no correlation existed in MR. OCPs, PCBs, steroid hormones, and bisphenol A were all detected in the ocean sediments, and total EDCs were measured in the range of 77 to 1796 ng g(-1) dry sediment weight. The EDCs were also found in untreated and treated municipal sewage samples with a removal efficiency of 83% for OCPs but no removal efficiency for 17α-ethinylestradiol.

[Dissolved silicon, inorganic nitrogen and phosphorus in the stream water of two small watersheds in Three Gorges area].

By using the method of fixed-pointed monitoring in streams of two small watersheds in Three Gorges Reservoir Area, the contents of dissolved silicon (DSi), dissolved inorganic nitrogen (DIN) and dissolved phosphorus (DP) are analyzed. The seasonal variation, the content ratio of DSi, DIN and DP, and the potential environmental problems are also discussed. The results indicate that: (10 In the two rivers, DSi content ranges from 0.18 to 19.89 mg x L(-1), DIN from 0.39 to 6.85 mg x L(-1) , and both are higher in the dry period than in the wet period; (2) DP content is from 0.01 to 0.08 mg x L(-1), which shows no significant difference between the dry and wet period; (3) The contents of DSi and DIN in Quxi River are higher than in Baota River, which may relate with the local agricultural activities, land use/land cover, fertilizer and so on; (4) The contents of DSi, DIN and DP in two small watersheds are all higher than in Three Gorge Reservoir, and the content ratio of DSi, DIN, DP is about 138 : 81 : 1 in Baota River, and 500 : 350 : 1 in Quxi River, which suggests that more attention should be paid to a potential threat to water environment such as Water-bloom.

Simultaneous quantification of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and pharmaceuticals and personal care products (PPCPs) in Mississippi river water, in New Orleans, Louisiana, USA.

An effective analytical method for simultaneously determining 16 polycyclic aromatic hydrocarbons (PAHs), 28 polychlorinated biphenyl (PCBs), and 12 pharmaceuticals and personal care products (PPCPs) has been developed to measure their concentrations in the Mississippi river waters in New Orleans, Louisiana, USA. The method involves the simultaneous extraction of the selected PAHs, PCBs, and PPCPs, from the aqueous phase by solid phase extraction using two-layer disks consisting of C(18) and SDB-XC, and collection of suspended solid in water samples by 0.2-0.6 microm filter in a single step. Target compounds adsorbed on the extraction disks were eluted with methanol, acetone, and dichloromethane. The suspended particles retained by the filter were sonically extracted using the same solvents. GC/MS was used for quantification of PAHs and PCBs directly and of PPCPs after derivatization. The analytical method was used in a 6-month field study of the Mississippi river water for contamination by PAHs, PCBs, and PPCPs and the following concentrations (ng/l) have been obtained: clofibric acid (3.2-26.7), ibuprofen (0-34.0), acetaminophen (24.7-65.2), caffeine (0-38.0), naproxen (0-135.2), triclosan (8.8-26.3), bisphenol A (0-147.2), carbamazepine (42.9-113.7), estrone (0-4.7), 17beta-estradiol (0-4.5), total PAHs (62.9-144.7), and total PCBs (22.2-163.4).

Naproxen removal from water by chlorination and biofilm processes.

Naproxen is an anti-inflammatory pharmaceutical that has been detected in natural and engineered aquatic environments. The primary aim of this research was to study chemical transformations of naproxen following chlorine oxidation, which is common in water and wastewater treatment systems. Synthetic waters containing elevated concentrations of naproxen were oxidized by free chlorine at naproxen:chlorine molar ratios of 0.02-3:1 and pH values of 5-9. The formation of naproxen products was dependent on pH, chlorine dosage and contact time. This study demonstrates that naproxen readily reacts with free chlorine and forms disinfection products. The formation of specific reaction products can vary depending on the characteristics of the water or wastewater and treatment operating conditions. More research is needed to identify intermediate and chemical reaction end products and to understand the reaction kinetics of naproxen chlorination for a range of water and wastewater treatment conditions. A secondary aim of this research was to study effects of naproxen and its chlorination products on biofilm processes, which are common in water and wastewater treatment systems and natural aquatic environments. A bioreactor was fed a naproxen solution and then fed a solution at the same naproxen concentration following contact with free chlorine. Results indicate that naproxen was not degraded biologically for the conditions of this study. In contrast, the naproxen solution containing products of chlorination caused an adverse response by discharging biomass from the bioreactor. Results therefore demonstrate that naproxen products of chlorination can adversely affect a biofilm process, which potentially can impact the performance of biofilm processes in natural and engineered aquatic environments. More research is needed to study naproxen chlorination reactions at low concentrations and in complex matrices, and to understand the toxicological relevance of naproxen and its products of chlorination in natural and engineered aquatic environments.

Pharmaceuticals and personal care products (PPCPs) and endocrine disrupting chemicals (EDCs) in stormwater canals and Bayou St. John in New Orleans, Louisiana, USA.

Samples were collected from two stormwater canals and a recreational urban waterway known as Bayou St. John in New Orleans, Louisiana, USA and analyzed for a range of pharmaceuticals and personal care products (PPCPs) and endocrine disrupting chemicals (EDCs). Concentrations of 7 PPCPs and EDCs were measured by a method that provides for simultaneous extraction and quantification of the following compounds: clofibric acid, naproxen, ibuprofen, fluoxetine, clorophene, triclosan, bisphenol A. The method also was used as an indicator of the occurrence of estrogenic compounds by targeting estrone and 17beta-estradiol. The two canals (Orleans and London) are used to drain a portion of the city's stormwater directly into the Mississippi River or Lake Pontchartrain. Bayou St. John is located between the two canals and supplied with water from Lake Pontchartrain. Results from the 6-month sampling period indicated the following concentration ranges for the two stormwater canals: naproxen (ND - 145 ng/l), ibuprofen (ND - 674 ng/l), triclosan (ND - 29 ng/l) and bisphenol A (1.9-158 ng/l). Concentrations of these target analytes increased with cumulative rainfall. For bayou waters, only naproxen (2.1-4.8 ng/l) and bisphenol A (0.9-44 ng/l) were detected. Estrone was detected but determined non-quantifiable for multiple sampling events at the 3 sites. None of the other target analytes (clofibric acid, fluoxetine, clorophene, and 17beta-estradiol) were detected above their method detection levels. Results of this study demonstrate the occurrence of PPCPs and EDCs in New Orleans stormwater canals and Bayou St. John. Results also demonstrate the use of this analytical technique as an indicator of non-point source sewage contamination in New Orleans stormwater canals.

Sewage treatment by a low energy membrane bioreactor.

A new membrane bioreactor (MBR) was developed for treatment of municipal wastewater. The MBR was mainly made up of an activated sludge reactor and a transverse flow membrane module, with an innovative configuration being in application between them. As a result, the transverse flow membrane module and low recirculation flow rate created advantages, such as lower energy consumption and more resistance to membrane fouling. The total energy consumption in the whole system was tested as 1.97+/-0.74 kWh/m(3) (permeate) while using periodical backwash with treated water and backflush with mixed liquor daily, being in the same level as a submerged membrane bioreactor, reported to be 2.4 kWh/m(3) (permeate). Energy consumption analysis in the system shows that the membrane module was more energy consuming than the other four parts listed as pump, aeration, pipe system and return sludge velocity lose, which consumed 37.66-52.20% of the total energy. The effluent from this system could be considered as qualified for greywater reuse in China, showing its potential application in the future.

Determination and discussion hydraulic retention time in membrane bioreactor system.

Based on the microorganism kinetic model, the formula for computing hydraulic retention time in a membrane bioreactor system (MBR) is derived. With considering HRT as an evaluation index a combinational approach was used to discuss factors which have an effect on MBR. As a result, the influencing factors were listed in order from strength to weakness as: maximum specific removal rate K, saturation constant Ks, maintenance coefficient m, maximum specific growth rate mu m and observed yield coefficient Yobs. Moreover, the formula was simplified, whose parameters were experimentally determined in petrochemical wastewater treatment. The simplified formula is theta = 1.1(1/beta-1) (Ks + S)/KX0, for petrochemical wastewater treatment K and Ks equaled 0.185 and 154.2, respectively.