Multiply restimulated human cord blood-derived Tregs maintain stabilized phenotype and suppressive function and predict their therapeutic effects on autoimmune diabetes.

BACKGROUND: Regulatory T cells (Tregs) are involved in the maintenance of immune homeostasis and immune regulation. Clinical trials on the adoptive transfer of Tregs have been ongoing for > 10 years. However, many unresolved issues remain in the production of readymade Treg products and selection of patients. Hence, this study aimed to develop a method to expand off-the-shelf Tregs derived from umbilical cord blood (UCB-Tregs) in vitro without changing their phenotype and inhibitory function. In addition, the study intended to design an approach to precisely select patients who are more likely to benefit from the adoptive Treg transfer therapy. METHODS: UCB-Tregs were isolated and cultured in a medium containing human recombinant IL-2 and rapamycin and then multiply restimulated with human T-activator CD3/CD28 dynabeads. The phenotype and suppressive capacity of Tregs were assessed on days 18 and 42. The relationship between the suppressive function of UCB-Tregs in vitro and clinical indicators was analyzed, and the ability of the in vitro suppressive capacity to predict the in vivo therapeutic effects was evaluated. RESULTS: UCB-Tregs expanded 123-fold and 5,981-fold at 18 and 42 days, respectively. The suppressive function of UCB-Tregs on the proliferation of immune cells at 42 days was not significantly different compared with that of UCB-Tregs obtained at 18 days. The suppression rate of UCB-Tregs to PBMCs was negatively correlated with the course of diabetes. Moreover, the high-suppression group exhibited a better treatment response than the low-suppression group during the 12-month follow-up period. CONCLUSIONS: Multiply restimulated UCB-Tregs expanded at a large scale without any alterations in their classical phenotypic features and inhibitory functions. The suppressive function of Tregs in vitro was negatively correlated with the disease duration. The present study revealed the possibility of predicting the in vivo therapeutic effects via the in vitro inhibition assay. Thus, these findings provided a method to obtain off-the-shelf Treg products and facilitated the selection of patients who are likely to respond to the treatment, thereby moving toward the goal of precision treatment.

Voluntary blood donation preferences in China: A discrete choice experiment among experienced and inexperienced donors.

BACKGROUND AND OBJECTIVES: Due partly to an ageing population, China faces an increasingly dire blood shortage crisis requiring greater voluntary blood donations. A better understanding of blood donation preferences can inform blood donation policies and potentially increase donations. We used an online survey and discrete choice experiment to achieve our study objective: identify the most influential structural facilitators and barriers to voluntary blood donation in China. MATERIALS AND METHODS: First, we identified six structural attributes (travel time, venue, donation volume, paid leave, scheduling and gifts) that were hypothesized to influence voluntary blood donation; attribute selection was based on a literature review and qualitative interviews. Second, a d-efficient design with 36 choice sets and 9 blocks was developed. Participants were asked to complete four choice sets, and in each choice set, they were asked to choose from three options: two voluntary blood donation scenarios and a 'Do not donate blood' option. Study participants were recruited through an online survey platform company in China. Voluntary blood donation preferences and preferences by blood donation history were estimated with random-parameter logit models and interaction terms. RESULTS: In 2022, 1185 individuals enrolled in the study. Most participants had college education (92%). Generally, participants preferred longer paid leave, lower blood donation volumes and gifts after donation. Based on interaction analyses, experienced and inexperienced donors exhibited similar preferences. CONCLUSION: Campaigns to increase voluntary blood donation rates in China should consider implementing paid leave after voluntary blood donation, lower blood donation volumes and small gifts conferred after donation.

Optimized design of permanent magnet for disk permanent magnet governor.

To research the magnetic field and mechanical characteristics of the permanent magnet governor, the static magnetic field of the sector permanent magnet is analyzed by the molecular current method in the permanent magnet governor. The magnetic flux distribution is acquired at any spatial position. Comparing the analytical value with the simulation value, the results show that they are basically consistent. Based on the analytical formula, the influence of the radial position, radial length, thickness, and pole number on the magnetic induction intensity of the permanent magnet governor is studied. Thus, it provides the theoretical reference for the structural optimized design. At the same time, a test bench was set up to measure the magnetic induction intensity. The calculation and experimental results show that the magnetic induction strength of the permanent magnet is increased by 27.5%, the axial component of the air gap flux density is increased by 14.3%, and the permanent magnet material is reduced by 7.84%.

Variable frequencies of peripheral T-lymphocyte subsets in the diabetes spectrum from type 1 diabetes through latent autoimmune diabetes in adults (LADA) to type 2 diabetes.

T lymphocytes are key players in the pathogenesis of autoimmune diabetes. We recruited subjects with T1D (n=81), LADA (n=82), T2D (n=95) and NGT (n=218) and analyzed the percentages of T-lymphocyte subsets, including T helper 1 (Th1), T helper 2 (Th2), T helper 17 (Th17), T cytotoxic 1 (Tc1), regulatory T cells (Tregs), effector T (Teff), naïve T, central memory T (Tcm), and effector memory T (Tem) cells by flow cytometry. LADA patients possessed similar frequencies of IFN-γ+CD4+ T (Th1), IFN-γ+CD8+ T and CD4+ Teff cells compared with T1D patients, but much lower than those of NGT subjects. Like T2D patients, LADA patients had increased frequencies of CD4+ Tem and CD8+ Tem cells with respect to T1D and NGT subjects. In LADA patients, Th2 cells were decreased while CD4+ Tcm cells were increased compared with NGT subjects. Notably, we observed significant negative correlations between the CD4+ Tcm cell frequency and C-peptide in LADA subjects. These data demonstrates that LADA patients possess T-cell subset changes resembling both T1D and T2D and represent the middle of the diabetes spectrum between T1D and T2D. Based on these T-cell subset alterations, we speculate that autoimmunity-induced ß-cell destruction and inflammation-induced insulin resistance might both be involved in the pathogenesis of LADA.

Validation of the Swedish Diabetes Re-Grouping Scheme in Adult-Onset Diabetes in China.

CONTEXT: This study applied the Swedish novel data-driven classification in Chinese newly diagnosed diabetic patients and validated its adoptability. OBJECTIVE: This study aimed to validate the practicality of the Swedish diabetes regrouping scheme in Chinese adults with newly diagnosed diabetes. DESIGN: Patients were classified into 5 subgroups by K-means and Two-Step methods according to 6 clinical parameters. SETTING: Ambulatory care. PATIENTS: A cross-sectional survey of 15 772 patients with adult-onset newly diagnosed diabetes was conducted in China from April 2015 to October 2017. INTERVENTION: None. MAIN OUTCOME MEASURES: Six parameters including glutamate decarboxylase antibodies (GADA), age of onset, body mass index (BMI), glycated hemoglobin A1c (HbA1c), homoeostatic model assessment 2 estimates of ß-cell function (HOMA2-B) and insulin resistance (HOMA2-IR) were measured to calculate the patient subgroups. RESULTS: Our patients clustered into 5 subgroups: 6.2% were in the severe autoimmune diabetes (SAID) subgroup, 24.8% were in the severe insulin-deficient diabetes (SIDD) subgroup, 16.6% were in the severe insulin-resistance diabetes (SIRD) subgroup, 21.6% were in the mild obesity-related diabetes (MOD) subgroup and 30.9% were in the mild age-related diabetes (MARD) subgroup. When compared with the Swedish population, the proportion of SIDD subgroup was higher. In general, Chinese patients had younger age, lower BMI, higher HbA1c, lower HOMA2-B and HOMA2-IR, and higher insulin use but lower metformin usage than the Swedish patients. CONCLUSION: The Swedish diabetes regrouping scheme is applicable to adult-onset diabetes in China, with a high proportion of patients with the severe insulin deficient diabetes. Further validations of long-term diabetes complications remain warranted in future studies.

Obesity-Related Glomerulopathy: A Latent Change in Obesity Requiring More Attention.

BACKGROUND: Obesity has become a major public health problem, and the prevalence of kidney diseases has increased in parallel. Among kidney diseases caused by metabolic disorders, obesity-related glomerulopathy (ORG) is secondary to obesity. SUMMARY: ORG is mainly caused by glomerular hyperfiltration, dysregulation of hormone and cytokine secretion in adipose tissues, and ectopic lipid accumulation in renal cells. ORG is pathologically characterized by glomerular hypertrophy, with or without focal and segmental glomerulosclerosis. Patients with ORG usually present with proteinuria concomitant with metabolic disorders such as dyslipidemia and hypertension. Weight loss, RAAS inhibitors, and improved insulin resistance can reduce the progression of ORG. CONCLUSION: ORG is a growing renal pathological change in obese individuals, and a comprehensive understanding of the disease is pivotal to avoid its occurrence and improve quality of life for those with obesity. Key Messages:This review comprehensively describes the characteristics of ORG in pathological changes, clinical manifestations, pathogeneses and treatments.

Analysis of potential hub genes involved in the pathogenesis of Chinese type 1 diabetic patients.

BACKGROUND: Type 1 diabetes is an autoimmune disease strongly related to genetic factors. Although studies on T1D susceptibility genes have achieved great progress, the molecular mechanism of T1D remains to be explained. METHODS: To explore the underlying mechanisms of T1D, bioinformatic analysis based on a microarray database was used to determine the key biomarkers of T1D as well as their biofunctions and interactions. The microarray database GSE55100 was downloaded from the Gene Expression Omnibus (GEO). Differentially expressed genes (DEGs) were processed by packages in R Software. The database for Annotation, Visualization, and Integrated Discovery (DAVID, version 6.8) was used to conduct gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The protein-protein interaction network was analyzed with the Search Tool for the Retrieval of Interacting Genes (STRING), and the module analysis was performed using Cytoscape. RESULTS: Seventy-eight DEGs and 13 hub genes were identified. The biofunctions and pathways of these DEGs were enriched in immune response, extracellular exosome, cytokine activity and antigen processing and presentation. Thirteen DEGs with MCODE score ≥2 were selected as hub genes including MMP9, ARG1, CAMP, CHI3L1, CRISP3, SLPI, LCN2, PGLYRP1, LTF, RETN, CEACAM1, CEACAM8 and MS4A3. CONCLUSIONS: The identification and analyses of the DEGs and hub genes from database GSE55100 provide novel prospectives of the pathogenesis of T1D.

GLP-1 receptor agonists and pancreatic safety concerns in type 2 diabetic patients: data from cardiovascular outcome trials.

PURPOSE: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have been suggested to be associated with an increased risk of pancreatitis and pancreatic cancer. The aim of this meta-analysis was to collect data from large-scale cardiovascular outcome trials (CVOTs) to assess the effect of GLP-1RAs on the incidence of acute pancreatitis and pancreatic cancer. METHODS: Database of Medline, Embase, and the Cochrane Central Register of Controlled Trials were extensively searched up to October 10, 2019. Randomized controlled trials were eligible if they compared GLP-RA with placebo as add-on therapy to standard care in T2DM patients, and reported outcomes required for cardiovascular safety studies and events of acute pancreatitis and/or pancreatic cancer. Peto odds ratio (OR) with 95% confidence interval (CI) was calculated for acute pancreatitis and pancreatic cancer. RESULTS: Seven CVOTs enrolling 56,004 patients with T2DM were identified, with a median follow-up time ranging from 1.3 to 5.4 years. A total of 180 cases of acute pancreatitis and 108 cases of pancreatic cancer were reported. The risk of either acute pancreatitis or pancreatic cancer with GLP-1-RA treatment was not significantly different from that observed in placebo arm (Peto OR [95% CI] 1.05 [0.78-1.40], P = 0.76, and 1.12 [0.77-1.63], P = 0.56, respectively), and the results remained robust to sensitivity analyses. CONCLUSION: Pooled analysis of CVOTs did not suggest any increased risk of either acute pancreatitis or pancreatic cancer with GLP-1RA treatment in T2DM patients.

The potential application of Cordyceps in metabolic-related disorders.

Changes in the global economy resulted in sedentary lifestyle and excessive calorie intake, increasing the incidence of metabolic diseases, which subsequently became a universal public concern. The difficulties of managing chronic diseases did not dampen researchers' enthusiasm for studying new therapeutics or adjuvant treatments. Cordyceps spp. is a kind of traditional Chinese herbal medicine; however, our understanding of this medicine remains at an initial stage. Recently, an increasing number of studies have demonstrated the potential of Cordyceps as a therapeutic agent for the effective treatment of metabolic-related disorders by exerting a variety of activities, including but not limited to anti-inflammatory, immunoregulatory, hypoglycemic, renoprotective and cardiovascular-protective effects. This article reviews the potential efficacy and underlying mechanisms of Cordyceps and its major bioactive ingredients in metabolic syndrome and its associated comorbidities.

Prevalence of Metabolic Syndrome and Its Determinants in Newly-Diagnosed Adult-Onset Diabetes in China: A Multi-Center, Cross-Sectional Survey.

Aim: The study aimed to investigate the prevalence of metabolic syndrome (MetS) and its determinants in newly-diagnosed adult-onset diabetes in China. Methods: From April 2015 to October 2017, 15,492 consecutive patients with diabetes diagnosed within 1 year and aged ≥30 years were recruited from 46 tertiary care hospitals in 24 cities across China. Glutamic acid decarboxylase autoantibody was assayed centrally and clinical data were collected locally. Classic type 1 diabetes mellitus (T1DM), latent autoimmune diabetes in adults (LADA) and type 2 diabetes mellitus (T2DM) were defined using the criteria of American Diabetes Association, Immunology of Diabetes Society and World Health Organization. MetS was defined using Chinese Diabetes Society's criteria. Logistic regression analysis was used to obtain odds ratios (OR) of determinants of MetS. Results: The overall prevalence of MetS was 66.5%, with the highest prevalence in T2DM (68.1%), followed by those in LADA (44.3%) and T1DM (34.2%) (P < 0.05 for all comparisons). After adjustment for traditional risk factors, T2DM had a 2.8-fold [95% confidence interval (CI): 2.36-3.37] MetS risk compared with LADA, whereas T1DM had significantly lower OR than LADA (OR: 0.68, 95% CI: 0.50-0.92). After further adjustment for insulin resistance, the OR of T2DM vs. LADA was slightly reduced but the OR of T1DM vs. LADA was greatly attenuated to non-significance (OR: 0.96, 95% CI: 0.70-1.33). In addition to types of diabetes, age, gender, geographical residence, education attainment, alcohol consumption and HOMA2-IR were independent determinants of MetS. Conclusions: MetS was highly prevalent, not only in T2DM but also in T1DM and LADA in Chinese newly diagnosed patients; higher risk of MetS in LADA than in T1DM was partially attributable to higher insulin resistance in LADA.

GLP-1 receptor agonists and risk of cancer in type 2 diabetes: an updated meta-analysis of randomized controlled trials.

PURPOSE: Some preliminary studies reported a link between GLP-1 receptor agonists (GLP-1RAs) and thyroid/pancreatic neoplasms, while its human relevance remained undetermined. The present meta-analysis was performed to collect information on cancers associated with GLP-1RAs in patients with type 2 diabetes mellitus (T2DM). METHODS: Medline, Embase, the Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science and ClinicalTrials.gov were extensively searched to identify randomized controlled trials that reported cancer events in T2DM patients treated with GLP-1RAs for at least 52 weeks, up to March 18, 2019. Odds ratio (OR) with 95% Confidence Interval (CI) was calculated for overall cancer (primary outcome), thyroid and pancreatic cancer. RESULTS: A total of 37 eligible trials were identified. The OR for overall cancer associated with GLP-1RAs was 1.03 (95% CI 0.95-1.12; p = 0.41) compared with comparators. Subgroup analyses showed that treatment with albiglutide was associated with a lower risk of overall cancer (OR 0.76 [95% CI 0.60-0.97]; p = 0.03), and no elevated risk of overall cancer was identified for other GLP-1RAs. No significant differences in the risks of thyroid nor pancreatic cancer were disclosed between GLP-1RAs and comparators. CONCLUSIONS: This meta-analysis did not suggest any increased risk of cancers associated with GLP-1RAs use in T2DM. The reduction in the risk of overall cancer associated with albiglutide needs to be examined further.

Investigation of the long-term desalination performance of membrane capacitive deionization at the presence of organic foulants.

A long-term performance of membrane capacitive deionization (MCDI) was investigated at the presence of organic matter, which has contributed to the understanding of fouling phenomena and energy efficiency. The commercial humic acid and sodium alginate were adopted as model substances representative of natural organic matter, and different ions including sodium and calcium were selected as important parameters considered in both model substances. The experimental results showed reductions in the salinity removal ability and increments of energy usage due to the organic fouling of ion-exchange membranes and carbon electrodes. Within a time interval of approximately 15 d, reductions of NaCl adsorbance with 5.3 and 3.3 mg per cycle were obtained for humics and alginate, respectively. Simultaneously, the energy consumptions increased by 56.9% for humics and 26.3% for alginate. Furthermore, the results in terms of calcium removal in organic feed and energy usage showed that it had a higher fouling potential in comparison to the ones for the sodium solution with equal conductivity and organic concentration. The morphology and composition of the fouling layer were further studied, and it was found that the organic adsorption onto the electrodes and the attachment or even penetration of organic matter on or into the ion-exchange membrane, which could not be efficiently desorbed during the regeneration cycle, were determined as a key problem of demineralized water production. Therefore, this study suggested the necessity of a pre-treatment to reduce the presence of organic matter for the sustainable operation of MCDI, hereby broaden the potential application fields.

Response of anaerobic membrane bioreactor to the presence of nano-Bi2WO6: reactor performance, supernatant characteristics, and microbial community.

Considering the increasing incorporation of manufactured nano-material into consumer products, there is a concern about its potential impacts in biological wastewater treatment. In this study, the response of anaerobic sludge to the presence of Bi2WO6 nano-particles (NPs) was investigated in the anaerobic membrane bioreactor (AnMBR). As the concentration of Bi2WO6 in the reactor was controlled around 1 mg/L, there was no significant difference in effluent water quality or bacterial activities before and after NP exposure, partially due to the microbial-induced NP aggregation and stable complex formation. However, with the increasing dosage of Bi2WO6 from 5 to 40 mg/L, great influences on the AnMBR performance were observed, including the reduction of COD removal efficiency, inhibition of the mechanization step, increased production of soluble microbial products, and enhanced secretion of extracellular polymer substrates. Additional investigation with high-throughput sequencing was conducted, clearly demonstrating that Bi2WO6 NPs induced changes in the bacterial community.

The Imbalance of B-Lymphocyte Subsets in Subjects with Different Glucose Tolerance: Relationship with Metabolic Parameter and Disease Status.

B lymphocytes are involved in inflammation and are related to insulin resistance in obesity and type 2 diabetes (T2D). This study investigated the phenotype and frequency of B-lymphocyte subsets in subjects recently diagnosed with T2D (n = 60), impaired glucose regulation (IGR, n = 73), and normal glucose tolerance (NGT, n = 169) by flow cytometry. T2D subjects had an increased percentage of CD19+CD23+ (B-2) cells and a decreased percentage of CD19+CD23- (B-1) cells attributing to CD19+CD23-CD5- (B-1b) cells, but not CD19+CD23-CD5+ (B-1a) cells, compared to NGT and IGR subjects. The proportion of CD19+CD5+CD1dhi (B10) cells did not differ between the IGR or T2D group and NGT controls. Of note, HbA1c and triglyceride showed a positive correlation with B-2 cells but an inverse correlation with B-1 and B-1b cells, which were independently associated with the presence of T2D by logistic regression models. In summary, this study shows an unbalanced proinflammatory phenotype of B-cell subsets correlated with glycemia and lipidemia in patients with T2D. Our data provide new insight into chronic activation of the immune system and subclinical inflammation in T2D. Further prospective studies are warranted to confirm our observations.

Altered Peripheral B-Lymphocyte Subsets in Type 1 Diabetes and Latent Autoimmune Diabetes in Adults.

OBJECTIVE: B lymphocytes play an important role in the immunopathogenesis of autoimmune diabetes. We hypothesized that the altered B-cell subset phenotype is associated with autoimmune diabetes. RESEARCH DESIGN AND METHODS: Patients with type 1 diabetes (T1D) (n = 81), latent autoimmune diabetes in adults (LADA) (n = 82), or type 2 diabetes (T2D) (n = 95) and healthy control subjects (n = 218) with normal glucose tolerance (NGT) were recruited. We determined the percentage of circulating B-lymphocyte subsets, including CD19(+)CD23(-)CD21(+) (marginal zone B [MZB]), CD19(+)CD23(+)CD21(-) (follicular B [FoB]), and CD19(+)CD5(+)CD1d(hi) (interleukin-10-producing regulatory B [B10]) cells by flow cytometry. RESULTS: Patients with T1D or LADA had increased percentages of MZB cells and decreased percentages of FoB cells compared with healthy control subjects with NGT and patients with T2D. Moreover, patients with T1D showed the lowest frequency of B10 cells compared with patients with LADA or T2D, whereas healthy control subjects expressed the highest frequency of B10 cells. Of note, the frequency of MZB cells was negatively associated and the frequency of FoB cells was positively associated with fasting C-peptide (FCP). The frequency of B10 cells was positively correlated with FCP and negatively correlated with hemoglobin A(1c). CONCLUSIONS: The data show that patients with T1D or LADA express an altered frequency of B-cell subsets, which is associated with islet function and glycemia. These findings suggest that B lymphocytes may be involved in loss of self-tolerance and ß-cell destruction and could be used as a biomarker and potential target for immunological intervention.

The clinical application of linagliptin in Asians.

Asia has a growing diabetic population. Linagliptin, a member of dipeptidyl peptidase-4 inhibitor class, is unique in its nonlinear pharmacokinetics with the characteristics of rapid attainment of steady state, little accumulation, predominantly nonrenal route of elimination, prolonged terminal half-life, and sustained inhibition of dipeptidyl peptidase-4 enzyme. No clinically relevant difference in pharmacokinetics was observed between Asians and non-Asians. The management of type 2 diabetes is increasingly challenging with the progression of disease, especially with the requirements of minimal hypoglycemia, weight gain, fluid retention, and other adverse effects. Linagliptin was efficacious and well-tolerated in Asian type 2 diabetes patients with or without renal or hepatic dysfunctions, comparable to that in Caucasians. This review will focus on the usage of linagliptin in clinical studies in Asians.

Performance of a submerged anaerobic membrane bioreactor with forward osmosis membrane for low-strength wastewater treatment.

A submerged anaerobic membrane bioreactor with forward osmosis membrane (FO-AnMBR) was operated at 25 °C for the treatment of synthetic wastewater. As the experiment progressed, the water flux reduced due to the membrane fouling and the increasing salinity in the reactor, and achieved at around 3.5 LMH in one cycle. It was worth noting that the level of salinity in the reactor was not a concern in terms of inhibition or toxic effects on the biological processes. The FO-AnMBR process exhibited greater than 96% removal of organic carbon, nearly 100% of total phosphorus and 62% of ammonia-nitrogen, respectively, suggesting a better removal efficiency than the conventional anaerobic membrane bioreactor. The methane and carbon dioxide compositions achieved concentrations of around 65%-78% and 22%-35%, respectively; and no obvious difference in the biogas composition was observed with the changes of conductivity. With respect to the methane yield, an average value of 0.21 L CH4 g(-1) COD was obtained, exhibiting the feasibility of energy recovery by this FO-AnMBR system. Additionally, an increase in the salinity enhanced the accumulation of soluble microbial products, especially for the proteins with 88.9% increment as the conductivity increased from 1.2 to 17.3 ms cm(-1). In contrast, a relatively stable concentration of extracellular polymer substances (EPS) was observed, indicating that the influence of conductivity on EPS cannot be directly correlated.

Interaction energy evaluation of soluble microbial products (SMP) on different membrane surfaces: role of the reconstructed membrane topology.

Soluble microbial products (SMP), a majority of organic matter in effluents, play a key role in membrane fouling. A series of filtration experiments were conducted, and demonstrated that the flux decrement rate was in order of cellulose acetate membrane (CA, 65.4%), polyvinylidene fluoride (PVDF, 47.9%) and polyether sulfones (PES, 29.2%). Results showed that the fouling behavior of membrane should be predicted from the combined knowledge of solution chemistry, surface chemical properties and surface morphology. To better understand the interactions between the SMP and different membranes, a technique for reconstructing the membrane surface topology was developed on the basis of statistical parameters obtained from atomic force microscopy. The interaction energy, represented by extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) potential, was calculated by surface element integration, allowing exploring the interaction energy profiles for different surfaces and providing considerable insights into the role of such interactions on the macroscopic fouling behavior. The resulting interaction energy differed considerably from the corresponding interaction between perfectly smooth surfaces. The great influence of protrusion on the membrane surface was to reduce the primary energy barrier height, thus rendering rough surface more favorable for deposition. An attractive energy region was immediately surrounded by each positive asperity as demonstrated in the roughness-engendered interaction energy maps. As the SMP approached closer to the membrane, they had a high probability of getting trapped in the attractive energy region, leading to a more rapid loss of flux than smooth membrane.

Correlating membrane fouling with sludge characteristics in membrane bioreactors: an especial interest in EPS and sludge morphology analysis.

Two submerged membrane bioreactors were operated for a period of 3 months to study the filtration behavior of normal sludge and bulking sludge. Comparison of sludge morphology and bound extracellular polymeric substances (EPS) from the two systems was made to elucidate the different filtration characteristics. Experimental results showed that the membrane fouling behavior induced by bulking sludge was more severe than normal sludge. Concomitantly, the adsorption tests and atomic force microscopy observation confirmed that the EPS properties played an important role in membrane adsorption, eventually causing the different fouling behavior. Correlations between image analysis information and diluted sludge volume index (DSVI) have been identified. The combinations of EFLI/FAI (the ratio between extended filamentous lengths and floc area), from factor and floc elongation related parameters (aspect ratio or roundness) were the preferred input candidates in autoregressive exogenous model to describe the filamentous bulking phenomena, which aided in predicting membrane fouling.