Rapid start-up and operational characteristics of partial denitrification coupled with anammox driven by innovative strategies

The Partial Denitrification-Anammox (PD/A) process established a low-consumption, efficient and sustainable pathway for complete nitrogen removal, which is of great interest to the industry. Rapid initiation and stable operation of the PD/A systems were the main issues limiting its engineering application in wastewater nitrogen removal. A PD/A system was initiated in a continuous stirred-tank reactors (CSTRs) in the presence of low concentration of organic matter, and the effects of organic matter types and COD/NO3--N ratios on the performance of the PD/A system, and microbial community characteristics were explored. The results showed that low concentrations of organic matter could promote the rapid initiation of the Anammox process and then the strategy of gradually replacing NO2--N with NO3--N could successfully initiate the PD/A system at 70 days. The type of organic matter had a significant effect on the initiation of the Anammox and the establishment of the PD/A system. Compared to glucose, sodium acetate was more favorable for rapid start-up and the synergy among microorganisms, and organic matter was lower, with an optimal COD/NO3--N ratio of 3.0. Microorganisms differed in their sensitivity to environmental factors. The relative abundance of Planctomycetota and Proteobacteria in R2 was 51 %, with the presence of three typical anammox bacteria, Candidatus_Brocadia, Candidatus_Kuenenia, and Candidatus_Jettenia in the system. This study provides a new strategy for the rapid initiation and stable operation of the PD/A process.

Waste iron scraps promote anammox bacteria to resist inorganic carbon limitation

The anaerobic ammonium oxidation (anammox) process is adversely affected by the limitation of inorganic carbon (IC). In this research, a new technique was introduced to assist anammox biomass in counteracting the adverse effects of IC limitation by incorporating waste iron scraps (WIS), a cheap and easily accessible byproduct of lathe cutting. Results demonstrated that reducing the influent IC/TN ratio from 0.08-0.09 to 0.04 resulted in a 20 % decrease in the nitrogen removal rate (NRR) for the control reactor, with an average specific anammox activity (SAA) of 0.65 g N/g VSS/day. Nevertheless, the performance of the WIS-assisted anammox reactor remained robust despite the reduction in IC supply. In fact, the NRR and SAA of the WIS-assisted reactor exhibited substantial improvements, reaching approximately 1.86 kg/(m3·day) and 0.98 g N/g VSS/day, respectively. These values surpassed those achieved by the control reactor by approximately 39 % and 51 %, respectively. The microbial analysis confirmed that the WIS addition significantly stimulated the proliferation of anammox bacteria (dominated by Candidatus Kuenenia) under IC limitation. The anammox gene abundances in the WIS-assisted anammox reactor were 3-4 times higher than those in the control reactor. Functional genes prediction based on the KEGG database revealed that the addition of WIS significantly enhanced the relative abundances of genes associated with nitrogen metabolism, IC fixation, and central carbon metabolism. Together, the results suggested that WIS promoted carbon dioxide fixation of anammox species to resist IC limitation. This study provided a promising approach for effectively treating high ammonium-strength wastewater using anammox under IC limitation.

Achieving smartphone-based colorimetric assay for Hg2+ with a bimetallic site strategy based on Hg2+-triggered oxidase-like catalytic activity of NSC/Co6Ni3S8 nanocomposite

Modulation of the nanozyme's catalytic activity is crucial for its real applications in detecting target analytes. Herein, we fabricated the nanocomposite (NSC/Co6Ni3S8) of N, S co-doped carbon and Co6Ni3S8 by a facile sol-gel approach. Compared to NSC/Ni9S8, NSC/Co6Ni3S8 with bimetallic active sites displayed better enzyme-mimetic activity. This nanocomposite could catalyze O2 to form ·O2- and oxidize colorless 3, 3', 5, 5'-tetramethylbenzidine (TMB) into blue oxTMB. The other two free radicals (h+ and ·OH) played minor roles during the catalytic reaction. Hg2+ could integrate with S2- to form HgS and the surface charges of O2 were transferred to Hg2+ to promote O2 adsorption. DFT theoretical calculations highlight that the main reasons for the enhancing effect of Hg2+ on color development results from electron transfer and increased adsorption energy of O2 molecules onto the surface of NSC/Co6Ni3S8. By employing the oxidase-like activity of NSC/Co6Ni3S8 and Hg2+-triggered promoting effect, a colorimetric sensing platform was established for Hg2+ assay with a linear range of 10-200 μg/L and detection limit of 3 μg/L. Through integration with a smartphone-based APP "Thing Identify" software, a visual colorimetric assay for Hg2+ was constructed with a detection limit of 5 μg/L. Compared to the data detected by the mercury vapor meter, the relative recoveries of 92.4-108.1% evidenced the higher accuracy of this smartphone-based visual detection. Overall, the NSC/Co6Ni3S8-based colorimetric assay is convenient, rapid, and visual, and can be applied for routine monitoring of Hg2+ in real-world waters under outdoor conditions.

Dietary cadmium health risk assessment for the Chinese population

Cadmium (Cd) has high rates of soil-to-plant transference, coupled with its non-biodegradability and persistence; long-term management of Cd in agriculture is thus required to ensure better soil and food security and safety. Identifications of regions with high soil Cd concentration or high dietary Cd intakes are critical public health priorities. Human health risk assessment for dietary Cd intake was thus undertaken by employing three approaches: FCA (food chain approach), TDA (total diet approach), and FQA (food quality approach). The correlation between green/total vegetable consumption rates and dietary Cd intake from vegetables was statistically significant. For consumption, the hazard quotients (HQs) calculated by FCA and TDA were all less than 1 except for Hunan and Sichuan province. For rice consumption, the HQs derived by FCA or TDA approach for eight provinces exceeded 1. Residents in Hubei, Guangxi, Jilin, Zhejiang, Liaoning, Shanghai, Sichuan, and Guangxi were more vulnerable due to their notable higher consumption rates.Weighted rankings of the health risk levels were determined to derive the comparative risk management priority. For Cd intake from vegetables, four provinces/cities have high relative priority; for Cd intake from grains, three provinces have high relative priority. The comparative risk management priority for Hunan and Sichuan was high for dietary intake from vegetables or rice. Weighted average HQs were derived to determine the integrated dietary Cd intake health risk levels for dietary intake from vegetables or grains. The risk levels for Hunan, Guangxi, Sichuan, and Zhejiang are high, so effective measures should be taken to reduce Cd dietary intakes to ensure health protection.It is envisaged that the methodology employed in this study could provide useful insights into how various approaches can be integrated to determine human health risk levels for Cd intake, so more effective and targeted measures can be taken accordingly for the relevant regions.

Microbial ecological responses of partial nitritation/anammox granular sludge to real water matrices and its potential application

Granular sludges are commonly microbial aggregates used to apply partial nitritation/anammox (PN/A) processes during efficient biological nitrogen removal from ammonium-rich wastewater. Considering keystone taxa of anammox bacteria (AnAOB) in granules and their sensitivity to unfavorable environments, it is essential to investigate microbial responses of autotrophic PN/A granules to real water matrices containing organic and inorganic pollutants. In this study, tap water, surface water, and biotreated wastewater effluents were fed into a series of continuous PN/A granular reactors, respectively, and the differentiation in functional activity, sludge morphology, microbial community structure, and nitrogen metabolic pathways was analyzed by integrating kinetic batch testing, size characterization, and metagenomic sequencing. The results showed that feeding of biotreated wastewater effluents causes significant decreases in nitrogen removal activity and washout of AnAOB (dominated by Candidatus Kuenenia) from autotrophic PN/A granules due to the accumulation of heavy metals and formation of cavities. Microbial co-occurrence networks and nitrogen cycle-related genes provided evidence for the high dependence of symbiotic heterotrophs (such as Proteobacteria, Chloroflexi, and Bacteroidetes) on anammox metabolism. The enhancement of Nitrosomonas nitritation in the granules would be considered as an important contributor to greenhouse gas (N₂O) emissions from real water matrices. In a novel view on the application of microbial responses, we suggest a bioassay of PN/A granules by size characterization of red-color cores in ecological risk assessment of water environments.

Analysis of bacterial community distribution characteristics in the downstream section of a cross confluence in a polluted urban channel

Channel confluences are common in urban rivers and caused complex hydrodynamic conditions in the downstream section, significantly influencing the distribution of pollutants and the microbial community. So far, the principles of bacterial community assembly and their linkages with environmental factors are poorly understood. In the present study, the hydrodynamic and pollution conditions were investigated in a typical channel confluence of an urban river in the Yangtze River delta area, China, and their impacts on the bacterial community structure in the water and sediment were characterized using 16S rRNA gene high-throughput sequencing technology. Based on the results, the flow velocity was the crucial factor influencing the dispersal of nutrients, organic compounds, and bacterial communities in the river water. Moreover, the sediments exhibited higher α-diversity and bacterial richness for nitrogen and sulfur cycling than the water. In addition to flow velocity, the contents of total organic carbon, total phosphorus, and heavy metals determined the sediment bacterial communities at varying depths. The predictive analysis of functional gene category indicated differences between the water and sediment communities in metabolic potentials and pathogen risk and provided guidance for water pollution control and the eco-remediation of urban rivers.

Metal-free graphene-based catalytic membranes for persulfate activation toward organic pollutant removal: a review

Owing to their ultrathin two-dimensional structure and efficient catalytic ability for persulfate activation, graphene-based nanocarbons exhibit considerable application potential in fabricating carbonaceous composite membranes for in situ catalytic oxidation to remove organic pollutants. This approach offers significant advantages over conventional batch systems. However, the relationships between the physicochemical properties of carbon mats and performance of graphene-based catalytic membranes in water purification remain ambiguous. Herein, we summarize the main mechanisms of in situ catalytic oxidation and the facile fabrication strategies of carbonaceous composite membranes. Different factors influencing the performance of graphene-based catalytic membranes are comprehensively discussed. The defective level, heteroatom doping, and stacking morphology of carbon mats and operational conditions during filtration play critical roles in the oxidative degradation of target pollutants. Long-term operation leads to the deterioration of catalytic activity and transmembrane pressure, especially in the complex water matrix. Finally, the present challenges and future perspectives are presented to improve the anti-fouling performance and catalytic stability of membranes and develop scalable fabrication methods to promote the engineering applications of in situ catalytic oxidation in real water purification.

Greenhouse gas emission benefits of adopting new energy vehicles in Suzhou City, China: A case study

The promotion of new energy in light-duty vehicles (LDVs) is considered as an effective approach for achieving low-carbon road transport targets. In this study, life cycle assessment was performed for five typical vehicle models in Suzhou City (fourth largest LDV stock in China): internal combustion engine vehicle (ICEV), hybrid electric vehicle (HEV), plug-in electric vehicle (PHEV), battery electric vehicle (BEV) and hydrogen fuel cell vehicle (HFCV). Their energy consumption, and greenhouse gas (GHG) and air pollutant emissions during vehicle and fuel cycles in 2020 were examined using the Greenhouse gases, Regulated Emissions, and Energy Use in Transportation (GREET) model. GHG emission reduction potential of LDV fleet was projected under various scenarios for 2021-2040. The results showed that BEVs exhibited advantages for replacing ICEVs over HEVs, PHEVs and HFCVs, taking into account China's road electrification policy. The GHG emission intensity of BEVs in 2040 was estimated to be 19-34% of ICEVs in 2020, with a deep decarbonized electricity mix and improved vehicle efficiency. For the aggressive Sustainable Development Scenario, the GHG emissions of LDVs would peak before 2026, ahead of China's target by 2030, and the ~ 100% share of EVs in 2040 would result in a lower GHG emissions, equivalent to the 2010 level. It highlights the importance of early action, green electricity mix, and public transport development in reducing GHG emissions of large LDV fleet.

[Effect of duodenal stump reinforcement on postoperative complications in patients undergoing laparoscopic radical gastrectomy]

Objective: To evaluate the influence of duodenal stump reinforcing on the short-term complications after laparoscopic radical gastrectomy. Methods: A retrospective cohort study with propensity score matching (PSM) was conducted. Clinical data of 1204 patients with gastric cancer who underwent laparoscopic radical gastrectomy at the First Affiliated Hospital of Army Medical University from April 2009 to December 2018 were collected. The digestive tract reconstruction methods included Billroth II anastomosis, Roux-en-Y anastomosis and un-cut-Roux- en-Y anastomosis. A linear stapler was used to transected the stomach and the duodenum. Among 1204 patients, 838 were males and 366 were females with mean age of (57.0±16.0) years. Duodenal stump was reinforced in 792 cases (reinforcement group) and unreinforced in 412 cases (non-reinforcement group). There were significant differences in resection range and anastomotic methods between the two groups (both P<0.001). The two groups were matched by propensity score according to the ratio of 1∶1, and the reinforcement group was further divided into purse string group and non-purse string group. The primary outcome was short-term postoperative complications (within one month after operation). Complications with Clavien-Dindo grade ≥ III a were defined as severe complications, and the morbidity of complication between the reinforcement group and the non-reinforcement group, as well as between the purse string group and the non-purse string group was compared. Results: After PSM, 411 pairs were included in the reinforcement group and the non-reinforcement group, and there were no significant differences in baseline data between the two groups (all P>0.05). No perioperative death occurred in any patient.The short-term morbidity of postoperative complication was 7.4% (61/822), including 14 cases of anastomotic leakage (23.0%), 11 cases of abdominal hemorrhage (18.0%), 8 cases of duodenal stump leakage (13.1%), 2 cases of incision dehiscence (3.3%), 6 cases of incision infection (9.8%) and 20 cases of abdominal infection (32.8%). Short-term postoperative complications were found in 25 patients (6.1%) and 36 patients (8.8%) in the reinforcement group and the non-reinforcement group, respectively, without significant difference (χ²=2.142, P=0.143). Nineteen patients (2.3%) developed short-term severe complications (Clavien-Dindo grade ≥IIIa), while no significant difference in severe complications was found between the two groups (1.7% vs. 2.9%, χ²=1.347, P=0.246). Sub-group analysis showed that the morbidity of short-term postoperative complication of the purse string group was 2.6% (9/345), which was lower than 24.2% (16/66) of the non-purse string group (χ²=45.388, P<0.001). Conclusion: Conventional reinforcement of duodenal stump does not significantly reduce the incidence of duodenal stump leakage, so it is necessary to choose whether to reinforce the duodenal stump individually, and purse string suture should be the first choice when decided to reinforce.

[Comparison of clinical efficacy and quality of life between uncut Roux-en-Y and Billroth II with Braun anastomosis in laparoscopic distal gastrectomy for gastric cancer]

Objective: To compare the clinical efficacy and quality of life between uncut Roux-en-Y and Billroth II with Braun anastomosis in laparoscopic distal gastrectomy for gastric cancer patients. Methods: A retrospective cohort study was performed. Inclusion criteria: (1) 18 to 75 years old; (2) gastric cancer proved by preoperative gastroscopy, CT and pathological results and tumor was suitable for D2 radical distal gastrectomy; (3) postoperative pathological diagnosis stage was T1-4aN0-3M0 (according to the AJCC-7th TNM tumor stage), and the margin was negative; (4) Eastern Cooperative Oncology Group (ECOG) physical status score <2 points, and American Association of Anesthesiologists (ASA) grade 1 to 3; (5) no mental illness; (6) able to answer questionnaires independently; (7) patients agreed to undergo laparoscopic distal gastrectomy and signed an informed consent. Exclusion criteria: (1) patients with severe chronic diseases and American Association of Anesthesiologists (ASA) grade >3; (2) patients with other malignant tumors; (3) patients suffered from serious mental diseases; (4) patients received neoadjuvant chemotherapy or immunotherapy. According to the above criteria, clinical data of 200 patients who underwent laparoscopic distal gastrectomy at the Department of General Surgery of the First Affiliated Hospital of Army Medical University from January 2016 to December 2019 were collected. Of the 200 patients, 108 underwent uncut Roux-en-Y anastomosis and 92 underwent Billroth II with Braun anastomosis. The general data, intraoperative and postoperative conditions, complications, and endoscopic evaluation 1 year after the surgery were compared. Besides, the quality of life of two groups was also compared using the Chinese version of the European Organization For Research and Treatment of Cancer (EORTC) quality of life questionnaire-Core 30 (QLQ-C30) and quality of life questionnaire-stomach 22 (QLQ-STO22). Results: There were no significant differences in baseline data between the two groups (all P>0.05). All the 200 patients successfully underwent laparoscopic distal gastrectomy without intraoperative complications, conversion to open surgery or perioperative death. There were no significant differences between two groups in operative time, intraoperative blood loss, postoperative complications, time to flatus, time to removal of gastric tube, time to liquid diet, time to removal of drainage tube or length of postoperative hospital stay (all P>0.05). Endoscopic evaluation was conducted 1 year after surgery. Compared to Billroth II with Braun group, the uncut Roux-en-Y group had a significantly lower incidences of gastric stasis [19.8% (17/86) vs. 37.0% (27/73), χ(2)=11.199, P=0.024], gastritis [11.6% (10/86) vs. 34.2% (25/73), χ(2)=20.892, P<0.001] and bile reflux [1.2% (1/86) vs. 28.8% (21/73), χ(2)=25.237, P<0.001], and the differences were statistically significant. The EORTC questionnaire was performed 1 year after surgery, there were no significant differences in the scores of QLQ-C30 scale between the two groups (all P>0.05), while the scores of QLQ-STO22 showed that, compared to the Billroth II with Braun group, the uncut Roux-en-Y group had a lower pain score (median: 8.3 vs. 16.7, Z=-2.342, P=0.019) and reflux score (median: 0 vs 5.6, Z=-2.284, P=0.022), and the differences were statistically significant (all P<0.05), indicating milder symptoms. Conclusion: The uncut Roux-en-Y anastomosis is safe and reliable in laparoscopic distal gastrectomy, which can reduce the incidences of gastric stasis, gastritis and bile reflux, and improve the quality of life of patients after surgery.

Carbonaceous composite membranes for peroxydisulfate activation to remove sulfamethoxazole in a real water matrix

In this study, we fabricated carbonaceous composite membranes by loading integrated mats of nitrogen-doped graphene, reduced graphene oxide, and carbon nanotubes (NG/rGO/CNTs) on a nylon microfiltration substrate and employed it for in-situ catalytic oxidation by activating peroxydisulfate (PDS) for the removal of sulfamethoxazole (SMX) in a real water matrix. The impact of coexisting organics on the performance of carbonaceous catalysis was investigated in the continuous filtration mode. Reusability testing and radical quenching experiments revealed that the non-radical pathways of surface-activated persulfate mainly contributed to SMX degradation. A stable SMX removal flux (r_SMX) of 22.15 mg m^-2·h^-1 was obtained in 24 h when tap water was filtered continuously under a low pressure of 1.78 bar and in a short contact time of 1.4 s, which was slightly lower than the r_SMX of 23.03 mg m^-2·h^-1 performed with deionized water as the control group. In addition, higher contents of protein-, fulvic acid-, and humic acid-like organics resulted in membrane fouling and significantly suppressed SMX removal during long-term filtration. Changes in the production of sulfate ions and the Raman spectra of carbon mats indicated that organics prevent the structural defects of the carbon matrix from participating in PDS activation. Moreover, NG/rGO/CNTs composite membranes coupled with activated persulfate oxidation exhibited good self-cleaning ability, because membrane fouling could be partly reversed by restoring filtration pressure during operation. This study provides a novel and effective oxidation strategy for efficient SMX removal in water purification, allowing the application of carbonaceous catalysis for the selective degradation of emerging contaminants.

Effects of Non-Invasive Brain Stimulation on Alzheimer's Disease

BACKGROUND

Previous meta-analyses did not explore the immediate and long-term effect of non-invasive brain stimulation (NIBS) on different cognitive domains in Alzheimer's disease (AD). The meta-analysis aimed to assess the therapy effect of repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) on different cognitive domains in AD in randomized controlled trials (RCTs).

METHODS

Studies published before December 2021 and exploring therapy effect of rTMS, tDCS on different cognitive domains in AD were searched in the following databases: PubMed and Web of Science. We used STATA 12.0 software to compute the standard mean difference (SMD) and a 95% confidence interval (CI).

RESULTS

The present study included 16 articles (including 372 AD patients treated with rTMS and 310 treated with sham rTMS) for rTMS and 11 articles (including 152 AD patients treated with tDCS and 134 treated with sham tDCS) for tDCS. The present study showed better immediate and long-term general cognitive function increase effects in AD given rTMS, compared to those given sham rTMS with random effects models (immediate effect: SMD = 2.07, 95% CI = 0.37 to 3.77, I2 = 97.8%, p < 0.001; long-term effect: SMD = 5.04, 95% CI = 2.25 to 7.84, I2 = 97.8%, p < 0.001). The present study showed no significant immediate and long-term effects of rTMS on attention, executive, language and memory functions. In addition, the present study showed no significant difference in immediate or long-term effects of tDCS on general cognitive function, attention, language or memory functions between tDCS group and sham tDCS group.

CONCLUSIONS

RTMS was an effective treatment technique for general cognitive function in AD, whereas tDCS showed no significant therapy effect on cognitive function in AD. More large-scale studies were essential to explore the effect of NIBS on various cognitive function in AD.

[Dibenzyl trisulfide inhibits proliferation and induces apoptosis of HN30 cells via Akt/ p53 signaling pathway]

OBJECTIVE

To explore the effect of dibenzyl trisulfide (DTS) on cell proliferation and apoptosis in human head and neck squamous cell carcinoma (HNSCC) HN30 cells.

OBJECTIVE

The effects of DTS on proliferation of HNSCC cell lines HN30, HN12, and SCC25 were examined by assessing colony formation ability of the treated cells. The effect of different concentrations of DTS on viability of HN30 cells was assessed using MTT assay. HN30 cells were treated with 3, 10, or 30 μmol/L DTS for 24 h, and the cell apoptosis and mitochondrial membrane potential (MMP) were detected using flow cytometry with annexin Ⅴ-FITC/PI double staining and JC-1 fluorescent probe staining. Western blotting was performed to determine the protein expressions of caspase-3, cleaved caspase-3 and Bcl-2 in the treated cells. The phosphorylation levels of Akt and p53 in HN30 cells were detected using Western blotting after treatment with 10 μmol/L DTS for 0.5, 1, 2, 4, 8, or 16 h.

OBJECTIVE

DTS at 1 μmol/L significantly inhibited the proliferation of HN30, HN12 and SCC25 cells as shown by colony formation assay. MTT assay showed that DTS dose-dependently decreased HN30 cell viability as compared with the solvent control group, and 100 μmol/L DTS produced the strongest inhibitory effect (P < 0.0001). Treatment with DTS below 30 μmol/L concentrationdependently promoted apoptosis (P < 0.01) and lowered the MMP (P < 0.01) of HN30 cells, and after treatment for 24 h, the cells showed significantly increased cleaved caspase-3 (P < 0.01) and decreased Bcl-2 expression (P < 0.01). Treatment with 10 μmol/L DTS for 16 h significantly inhibited Akt phosphorylation (P < 0.001) and enhanced p53 phosphorylation (P < 0.01) in HN30 cells.

OBJECTIVE

DTS inhibits proliferation and induces apoptosis of HN30 cells possibly through mechanisms involving the inhibition of Akt and the activation of p53.

The in situ catalytic oxidation of sulfamethoxazole via peroxydisufate activation operated in a NG/rGO/CNTs composite membrane filtration

Metal-free carbonaceous composite membranes have been proven to effectively drive novel in situ catalytic oxidation for the degradation of organic pollutants via persulfates activation. In this study, nitrogen-doped graphene (NG) was employed as a modifier to enhance the catalytic activity of the carbon mats by assembly with reduced graphene oxide (rGO) and carbon nanotubes (CNTs) on the top of a nylon supporter. The morphology and performance of the NG/rGO/CNTs composite membrane were compared to those obtained without the addition of NG (rGO/CNTs). Owing to the larger nanochannels for water delivery and stronger hydrophobicity on the surface, the NG/rGO/CNTs composite membrane shows a superior low-pressure filtration performance in favor of energy-saving operation. For the in situ catalytic oxidation of the NG/rGO/CNTs composite membrane through the activation of peroxydisufate (PDS), the average removal rate of sulfamethoxazole (SMX), one of frequently detected sulfonamide antibiotics in water, can reach 21.7 mg·m^-2·h^-1 under continuous filtration mode, which was 17% more rapid than that of the rGO/CNTs, resulting in significant detoxifying of the oxidation intermediates. Owing to the addition of NG into the carbon mats, the reactive nitrogen-doped sites identified by X-Ray photoelectron spectroscopy (XPS), such as pyridinic and graphitic N, played important roles in PDS activation, while both the radical and non-radical pathways were involved in in situ catalytic oxidation. According to the experimental evidence of the effects that solution environment has on the SMX removal and transmembrane pressure, the NG/rGO/CNTs composite membrane shows a relatively high resistance to changes in the solution pH, chloride ion inhibition, and background organics fouling. These results suggest a new approach to the application of activated persulfate oxidation in water treatment, such that improvements to the reaction stability warrant further investigation.

Accuracy of cold sensibility testing on teeth with full-coverage restorations: a clinical study

AIM

This clinical study evaluated the reliability of the 1,1,1,2-tetrafluoroethane (Endo Ice) cold test to determine the pulpal diagnosis of teeth with full-coverage restorations (FCR). The effect of several variables on its reliability was also investigated.

METHODOLOGY

Data collected from 825 patients treated in the Advanced Education Program in Endodontics at the University of Iowa, USA were analysed. The experimental group included 425 teeth with FCR, whilst the control group consisted of 400 teeth with natural crowns (NC). The pulp sensibility test results, tooth type, tooth number, type of crown, age, gender, presence or absence of caries and recent use of analgesics were recorded. Bivariate analyses were performed to assess the variables associated with the accuracy of dental pulp sensibility tests for either teeth with crowns or teeth without crowns using chi-square tests, Fisher's exact tests, Cochran-Mantel-Haenszel tests, and the Wilcoxon rank-sum tests. A P-value of less than 0.05 was used as a criterion for statistical significance, and a P-value in 0.05 < P < 0.10 was used as a criterion for marginal relevance.

RESULTS

The sensibility test results for FCR teeth had an accuracy of 0.866; sensitivity of 0.835; specificity of 0.879; a positive predictive value of 0.746; and a negative predictive value of 0.926. The data indicated a significant difference in the accuracy of pulp sensibility test results between the experimental and control groups (P < 0.001). Although the cold test in FCR teeth still had high accuracy, teeth with NC were significantly more likely to have true-positive and true-negative results (91.5% NC vs. 86.6% FCR, P = 0.024). No significant differences between FCR and NC were found concerning gender, tooth type, type of crown, the presence of abutment and recent use of analgesic (P > 0.05).

CONCLUSION

Pulp sensibility cold testing with 1,1,1,2-tetrafluoroethane (TFE) on teeth with FCR was less accurate than on teeth without full-coverage crowns. However, the use of TFE cold testing is still a relevant and reliable diagnostic tool, particularly for teeth with a pulpal diagnosis of symptomatic irreversible pulpitis. Clinicians should routinely carry out cold pulp sensibility testing on teeth when making a pulpal diagnosis.

Conversion of full nitritation to partial nitritation/anammox in a continuous granular reactor for low-strength ammonium wastewater treatment at 20 °C

The feasibility of converting full nitritation to partial nitritation/anammox (PN/A) at ambient temperature (20 °C) was investigated in a continuous granular reactor. The process was conducted without anammox bacteria inoculation for the treatment of 70 mg L^-1 of low-strength ammonium nitrogen wastewater. Following the stepwise increase of the nitrogen loading rate from 0.84 to 1.30 kg N m^-3 d^-1 in 320 days of operation, the removal efficiency of total inorganic nitrogen (TIN) exceeded 80% under oxygen-limiting conditions. The mature PN/A granules, which had a compact structure and abundant biomass, exhibited a specific TIN removal rate of 0.11 g N g^-1 VSS d^-1 and a settling velocity of 70.2 m h^-1. This was comparable with that obtained at above 30 °C in previous reports. High-throughput pyrosequencing results revealed that the co-enrichment of aerobic and anaerobic ammonium-oxidizing bacteria identified as genera Nitrosomonas and Candidatus Kuenenia, which prompted a hybrid competition for oxygen and nitrite with nitrite-oxidizing bacteria (NOB). However, the overgrowth of novel NOB Candidatus Nitrotoga adapted to low temperatures and low nitrite concentration could potentially deteriorate the one-stage PN/A process by exhausting residual bulk ammonium under long-term excessive aeration.

Baicalin attenuates endometritis in a rabbit model induced by infection with Escherichia coli and Staphylococcus aureus via NF-κB and JNK signaling pathways

In this study, a rabbit endometritis model was developed to study cow endometritis. In addition, the protective effects of baicalin (a flavonoid) against endometritis were investigated. Clinical symptoms, differential leukocyte counting, uterine secretion smear microscopy and chemical examination, urine testing, and signs of necropsy showed abnormal changes and inflammatory responses in the uterus of rabbits. Histopathological results revealed visible inflammatory exudates and blood spots between intercellular spaces which confirmed that the rabbit endometritis model was successfully developed. Most importantly, these inflammatory signs were partially attenuated with baicalin treatment. The data revealed that the increased body temperature and leukocyte cells, pus, and the detachment of epithelial cells were alleviated with baicalin administration in a dose-dependent manner. Histopathological tissue changes such as inflammatory cells infiltrates, hyperemia, hemorrhages, and shedding of epithelial cells were partially attenuated with baicalin treatment. In addition, the mRNA expression of inflammation-related genes (iNOS, IL-1β, TNF-α, IL-10, IL-4, and IL-6) was significantly altered in RAW264.7 cells after LPS treatment. Further, the phosphorylated protein expression of JNK, p65, and IκBα were significantly reduced with LPS treatment. Intriguingly, baicalin pretreatment reversed the alteration in mRNA expression of inflammation-related genes and significantly reduced the phosphorylation of JNK, p65, and IκBα. In summary, our results suggest that baicalin has protective effects on bacterial-induced endometritis in rabbits that involve the suppression of NF-κB and JNK signaling pathways and pro-inflammatory cytokines.

[Long-term efficacy of robotic radical total gastrectomy for gastric cancer and analysis of prognostic factors]

Objective: To analyze long-term outcomes and prognostic factors of gastric cancer patients after robotic radical total gastrectomy. Methods: A retrospective case-control study was conducted. Inclusion criteria: (1) receiving robotic radical total gastrectomy; (2) gastric adenocarcinoma was confirmed by postoperative pathology; (3) no previous history of other malignant tumors; (4) no preoperative chemotherapy or radiation therapy performed. Exclusion criteria: (1) age <18 years old or age >80 years old;(2)distant metastasis before surgery, or palliative surgery; (3) conversion to laparotomy;(4) R1 or R2 resection; (5)emergency surgery; (6) remnant gastric cancer or recurrence; (7)died of severe complications during hospitalization or within 1 month after surgery. Overall survival rates (OS) and disease-free survival rates (DFS) were evaluated using the Kaplan-Meier method. Cox regression analysis was used to identify prognosis factors for overall survival. Results: According to the above criteria, 166 gastric cancer patients who underwent robotic radical total gastrectomy between March 2010 and November 2018 were included in this study. Roux-en-Y reconstruction was performed in all patients. Reconstruction were achieved using extracorporeal method through a minilaparotomy in 149 case and intracorporeal anastomosis in 17 cases. The number of harvested lymph nodes was (34.8±17.5), and the number of harvested lymph nodes at group 2 was (10.1±6.7). The number of patients with lymph node metastasis of group 2 was 73 (44.0%). The median follow-up time was 25 months (range 2-109). There were 55 (33.1%) cases of recurrence during follow-up. The 3- and 5-year overall survival rates were 55.8% and 46.2% respectively. The 3- and 5-year disease-free survival rates were 53.4% and 45.4% respectively. The 5-year overall survival rates grouped based on TNM stage were 78.9% for stage I, 58.5% for stage II, and 37.1% for stage III. The 5-year disease-free survival rates grouped based on TNM stage were 78.9% for stage I, 59.2% for stage II, and 34.6% for stage III. Univariate analysis suggested that TNM stage, the number of harvested lymph nodes and number of harvested lymph nodes at group 2 were associated with overall survival rates (all P<0.05). Multivariate analyses revealed that TNM stage (P<0.001; stage IIIB: HR=5.357, 95%CI:1.182 to 24.275; stage IIIC: HR=11.937, 95%CI: 2.677 to 53.226) and number of harvested lymph nodes at group 2 (P=0.034; 6-10: HR=0.562,95%CI:0.326 to 0.969; >10: HR=0.388, 95%CI: 0.176 to 0.857) were independent prognostic factors for overall survival. Conclusion: The long-term outcomes of robotic radical total gastrectomy were satisfactory. TNM stage and number of harvested lymph nodes at group 2 were independent prognostic factors for overall survival.

[Comparison of clinical efficacy between proximal gastrectomy with double tract reconstruction and total gastrectomy with Roux-en-Y reconstruction for proximal gastric cancer]

Objective: To compare the clinical efficacy of proximal gastrectomy with double tract reconstruction (PG-DT) and total gastrectomy with Roux-en-Y reconstruction (TG-RY) for proximal gastric cancer. Methods: The retrospective study was conducted. Clinicopathological data of 132 patients with proximal gastric cancer confirmed by pathology who underwent PG-DT (n=51) or TG-RY (n=81) by the same surgeon team in Southwest Hospital of Army Military Medical University between January 2006 and December 2016 were collected. Patients with preoperative neoadjuvant therapy, non-R0 resection and non-adenocarcinoma confirmed by pathology were excluded. Observation indicators included intraoperative (operation time and blood loss); postoperative (time to flatus, hospital stay, total complications, metastasis of lymph nodes around distal side of stomach from cases undergoing TG-RY), follow-up (long-term hemoglobin level, incidence of anemia, and survival) parameters. Survival analysis was conducted using the Kaplan-Meier method, and Log-rank test was used to compare survival difference between two groups. Results: No statistically significant differences were found between two groups in the baseline data, including age, gender, BMI, hemoglobin level before operation, postoperative TNM stage, tumor size and histological differentiation between two groups (all P>0.05). There were no significant differences between PG-DT and TG-RY in intraoperative blood loss [200 (200) ml vs. 200 (195) ml, Z=-1.860, P=0.063], time to flatus [(2.7±1.0) days vs. (2.6±1.1) days, t=0.225, P=0.823], postoperative hospital stay [10(3) days vs. 10 (4) days, Z=-0.449, P=0.654] and morbidity of perioperative complications [5.9% (3/51) vs. 8.6% (7/81), χ(2)=0.081, P=0.775]. Compared with the TG-RY group, PG-DT group had longer total operative time [294 (97) minutes vs. 255 (71) minutes, Z=-3.148, P=0.002]. The hemoglobin data of 42 patients with PG-DT and 56 patients with TG-RY were collected 1 year after operation. The incidence of anemia in PG-DT group was lower than that of TG-RY group [64.2%(27/42) vs. 82.1% (46/56), χ(2)=4.072, P=0.045], and PG-DT group had higher level of hemoglobin than TG-RY group [(114.4±16.3) g/L vs. (106.6±15.0) g/L, t=2.435, P=0.017]. There were 4 cases (4/81, 4.9%) with metastasis of lymph nodes around distal side of stomach in TG-RY group. All of these 4 tumors were T4 in depth and were more than 5 cm in diameter. The median follow-up period was 26 (1 to 110) months. One-year, 3-year and 5-year survival rates were 93.2%, 65.3% and 55.0% in PG-DT group, and 85.8%, 63.8% and 47.2% in TG-RY group, respectively without significant difference (χ(2)=0.890, P=0.345). Conclusions: Compared with TG-RY, PG-DT has the same safety and feasibility for proximal gastric cancer. Although the operative time is a little longer than TG-RY, PG-DT has advantages in improving the postoperative hemoglobin level.

[Comparative study on clinical efficacy of two surgical methods for gastric gastrointestinal stromal tumors at unfavorable position]

Objective: To investigate the safety and feasibility of laparoscopic operation in thetreatment of gastric gastrointestinal stromal tumor (GIST) at unfavorable positions. Methods: A retrospective cohort study was conducted to analyze the clinical data of patients with gastric GIST at unfavorable positions confirmed by pathology after surgery (laparoscopy or laparotomy) at the Southwest Hospital of the Army Medical University and the Minda Hospital of Hubei Minzu University from June 2008 to June 2018. The unfavorable positions of stomach are defined as the esophagogastric junction, the proximal cardia of gastric lesser curvature, the pylorus of stomach, the posterior wall of stomach and the antrum of stomach.Exclusion criteria:(1) preoperative chemotherapy or imatinib therapy; (2) diameter of tumor > 10 cm; (3) tumor metastasis or concurrence of other malignant tumors. A total of 244 patients (238 in Southwest Hospital and 6 in Minda Hospital) were enrolled, including 122 males and 122 females with age of 41-70years. Operative methods should be adopted according to patients' wishes. There were 146 cases in the laparoscopic surgery group and98 cases in the open surgery group. The intraoperative blood loss, operative time, postoperative first flatus time, postoperative firstfeeding time,average hospital stay, morbidity of postoperative complication,1-,3-,and 5-year recurrence free survival(RFS) and overall survival (OS)rate were compared between the two groups. Results: There were no significant differences in sex, age, tumor size, tumor risk grade or growth pattern between the laparoscopic and the open surgery groups (all P>0.05),and these two groups were comparable. Compared with open group, laparoscopic group had less intraoperative blood loss [(31.4±2.3) ml vs. (143.9±3.7) ml, t=292.800, P<0.001], shorter postoperative first flatus time [(2.1±0.7) days vs.(3.8±0.8) days, t=17.550,P<0.001], shorter postoperative first feeding time [(2.1±0.5) days vs.(2.3±1.7) days, t=1.339,P=0.020], shorter hospital stay [(8.6±2.6) days vs. (13.6±3.2) days, t=13.410, P<0.001], and lower morbidity of postoperative complication [16(11.0%) vs. 21(21.4%),χ²=4.996,P=0.025], whose differences were statistically significant. While the operation time was similar in two groups [(124.7±15.8) minutes vs. (120.9±14.5) minutes, t=1.903,P=0.058]. The median follow-up of all the patients was 43 (1 to 119) months.In laparoscopic group and open group, the 1-, 3- and 5-year RFS were 94.5% vs. 93.9%, 91.1% vs. 90.8%,and 82.2% vs. 81.6%, respectively, and 1-, 3- and 5-year OS were 98.6% vs. 95.9%, 95.9% vs. 94.9%,and 91.1% vs. 88.8%, respectively, whose differences were not statistically significant (all P>0.05). Conclusion: In the experienced gastrointestinal surgery center, laparoscopic resection of gastric GIST at unfavorable position is safe and feasible, achieving the same efficacy of open surgery.

Microbial community response to influent shift and lowering temperature in a two-stage mainstream deammonification process

The effects of influent shift from synthetic wastewater to anaerobically pretreated actual sewage coupling with lowering temperature on microbial community of a two-stage partial nitritation (PN)-anammox process were evaluated through high-throughput sequencing. Venn diagrams and Hill numbers showed the significantly increased bacterial diversity both in the PN and anammox reactor. However, taxonomic analysis indicated that outstanding enrichment of heterotrophic bacteria and reduction of autotrophic species mainly occurred in the PN reactor, while nearly all of the dominant bacteria in the anammox reactor only slightly decreased in abundance. Moreover, immigrant bacteria from the PN reactor to the following anammox reactor had no negative effect on the anammox function. These results implied the positive role of the first-stage PN in maintaining the stability of the following anammox community. Nitrosomonas europaea (17.9-52.9%) and one cluster (19.2-27.7%) within Candidatus Brocadia remained as the dominant functional species in the PN and anammox reactor, respectively.

Rapid start-up of a nitritation granular reactor using activated sludge as inoculum at the influent organics/ammonium mass ratio of 2/1

Partial oxidation of ammonium to nitrite is a pre- and crucial step to achieve shortcut biological nitrogen removal from ammonium-rich wastewater. In the present study, a nitritation granular reactor using activated sludge as inoculum was started up in a sequencing batch reactor (SBR) at a fixed influent C/N ratio of 2:1. Variations in the reactor performance, functional bacteria activities, sludge morphology and bacterial community structure were investigated. Results showed the formation of compact granules was achieved in 55 days, and a stable nitrite accumulation rate of 0.68 kg N·m^-3·d^-1 was maintained in the following period. With a rapid growth of granular size, the total nitrogen removal by simultaneous nitritation/denitritation was progressively increased to 50%. In sludge granulation, the significant enrichment of r-strategist ammonium oxidizing bacteria (Nitrosomonas) was identified. Additionally, both high free ammonia concentration and extra nitrite competition by heterotrophic denitrifiers were critical to suppress nitrite oxidizing bacteria effectively.

The glycosyltransferase ST6Gal-I is enriched in cancer stem-like cells in colorectal carcinoma and contributes to their chemo-resistance

PURPOSE

Presence of cancer stem cells (CSCs) contributes to tumor outgrowth, chemo-resistance and relapse in some cancers including colorectal carcinoma (CRC). The current characterization methods of CSCs in CRC only allows enrichment of CSCs but not their purification. Recent reports showed that ST6 beta-galactoside alpha-2,6-sialyltransferase 1 (ST6Gal-I) plays an essential role in protecting tumor cells against harsh environment like oxidative stress and nutrient deprivation. Therefore, whether ST6Gal-I may be highly expressed in CSCs or whether it may enhance resistance of tumor cells to chemotherapy deserves exploration.

METHOD

ST6Gal-I levels were determined in CRC specimens, compared to paired normal colorectal tissue, and examined in CD133+ vs CD133- CRC cells, and CD44+ vs CD44- CRC cells. ST6Gal-I levels and their association with patient survival were examined. In vivo, 2 CRC cell lines Caco-2 and SW48 were transduced with two lentiviruses, one lentivirus carrying a green fluorescent protein reporter and a luciferase reporter under a cytomegalovirus promoter to allow tracing tumor cells by both fluorescence and luciferase activity, and one lentivirus carrying a nuclear red fluorescent protein under the control of ST6Gal-I promoter to allow separation of ST6Gal-I+ vs ST6Gal-I- CRC cells. Tumor sphere formation, resistance to fluorouracil-induced apoptosis, and frequency of tumor formation after serial adoptive transplantation were done on ST6Gal-I+ vs ST6Gal-I- CRC cells.

RESULT

ST6Gal-I levels were significantly upregulated in clinically obtained CRC specimens, compared to paired normal colorectal tissue. Poorer patient survival was detected in ST6Gal-I-high CRC, compared to ST6Gal-I-low subjects. Higher levels of ST6Gal-I were detected in CD133+ CRC cells than CD133- CRC cells, and in CD44+ CRC cells than in CD44- CRC cells. Compared to ST6Gal-I- CRC cells, ST6Gal-I+ CRC cells generated significantly more tumor spheres in culture, were more resistant to fluorouracil-induced apoptosis likely through upregulating cell autophagy, and generated tumor more frequently after serial adoptive transplantation.

CONCLUSION

ST6Gal-I may be highly expressed in the cancer stem-like cells in CRC and enhances cancer cell resistance to chemotherapy.

Single-stage autotrophic nitrogen removal process at high loading rate: granular reactor performance, kinetics, and microbial characterization

For the possible highest performance of single-stage combined partial nitritation/anammox (PNA) process, a continuous complete-mix granular reactor was operated at progressively higher nitrogen loading rate. The variations in bacterial community structure of granules were also characterized using high-throughput pyrosequencing, to give a detail insight to the relationship between reactor performance and functional organism abundance within completely autotrophic nitrogen removal system. In 172 days of operation, a superior total nitrogen (TN) removal rate over 3.9 kg N/(m³/day) was stable implemented at a fixed dissolved oxygen concentration of 1.9 mg/L, corresponding to the maximum specific substrate utilization rate of 0.36/day for TN based on the related kinetics modeling. Pyrosequencing results revealed that the genus Nitrosomonas responsible for aerobic ammonium oxidation was dominated on the granule surface, which was essential to offer the required niche for the selective enrichment of anammox bacteria (genus Candidatus Kuenenia) in the inner layer. And the present of various heterotrophic organisms with general functions, known as fermentation and denitrification, could not be overlooked. In addition, it was believed that an adequate excess of ammonium in the bulk liquid played a key role in maintaining process stability, by suppressing the growth of nitrite-oxidizing bacteria through dual-substrate competitions.

Role of secreted protein acidic in hematogenous metastasis of gastric cancer

OBJECTIVE

To investigate tumor microenvironment of metastasis (TMEM) and the expression of SPARC (secreted protein acidic and rich in cysteine) in gastric cancer, and their relationships with hematogenous metastasis.

PATIENTS AND METHODS

Twenty-six pairs of cases with gastric cancer were enrolled, in which there were 26 cases with distant organ metastases and 26 cases of gastric cancer without organ metastases as controls. TMEM (by double-stained immunohistochemistry) and the expression of SPARC were determined in twenty-six pairs of cases. In addition, we selected 48 patients to detect the expression of SPARC, VEGF (vascular endothelial growth factor), and evaluated TAMs (tumor associated macrophages), MVD (the microvessel density), MPI (microvessel pericyte coverage index), and TMEM in gastric cancer tissues by immunohistochemistry.

RESULTS

TMEM count was significantly higher in the metastatic gastric cancer tissues than that in non-metastatic cancer tissues in a case-control study (p<0.01). On the contrary, SPARC expression was lower in the metastatic gastric cancer tissues than that in non-metastatic cancer tissues. TMEM count, TAMs, and MVD were significantly correlated with invasion depth, histological type and TNM stage (p<0.05 or p<0.01). Expression of SPARC and VEGF were significantly correlated with tumor histological types, invasion depth, differentiation and lymph node metastasis of patients (p<0.05). SPARC and VEGF expression in stromal cells of gastric cancer tissues were significantly correlated with TAMs, MVD and MPI (p<0.05). In addition, SPARC expression was significantly inversely correlated with VEGF expression in gastric cancer tissues (p<0.05).

CONCLUSIONS

TMEM was detected in initial gastric cancer resection and closely correlated with hematogenous metastasis. Furthermore, SPARC may be involved in gastric cancer metastasis by effecting on tumor microenvironment.

Magnetic Fluctuations, Precursor Phenomena, and Phase Transition in MnSi under a Magnetic Field

The reference chiral helimagnet MnSi is the first system where Skyrmion lattice correlations have been reported. At a zero magnetic field the transition at T_{C} to the helimagnetic state is of first order. Above T_{C}, in a region dominated by precursor phenomena, neutron scattering shows the buildup of strong chiral fluctuating correlations over the surface of a sphere with radius 2π/ℓ, where ℓ is the pitch of the helix. It has been suggested that these fluctuating correlations drive the helical transition to first order following a scenario proposed by Brazovskii for liquid crystals. We present a comprehensive neutron scattering study under magnetic fields, which provides evidence that this is not the case. The sharp first order transition persists for magnetic fields up to 0.4 T whereas the fluctuating correlations weaken and start to concentrate along the field direction already above 0.2 T. Our results thus disconnect the first order nature of the transition from the precursor fluctuating correlations. They also show no indication for a tricritical point, where the first order transition crosses over to second order with increasing magnetic field. In this light, the nature of the first order helical transition and the precursor phenomena above T_{C}, both of general relevance to chiral magnetism, remain an open question.

Abstract P5-09-02: Breast cancer risk prediction using a polygenic risk score in women of African ancestry: Findings from GWAS in breast cancer in the African diaspora

Background: Multiple common susceptibility loci for breast cancer (BC) have been identified/confirmed in Caucasian women. Combination of these SNPs into a polygenic risk score (PRS) could improve risk stratification and provide guidance for preventive and screening strategies. However, due to differences in allele frequencies of genetic variants, tumor characteristics between women of African and European ancestries, we sought to evaluate the association of PRS with BC in a large consortium of African women.

Methods: The GWAS in BC in the African Diaspora (ROOT consortium) included 3686 participants of African ancestry from Nigeria, USA, and Barbados (1657 cases, 2029 controls). PRS was constructed from the published odds ratios (ORs) from 90 susceptibility loci for BC. Logistic regression was used to examine its association with overall BC risk as well as associations by hormone receptor status, family history and other clinical features.

Results: One unit change in the PRS was associated with an OR of 1.13 (95% CI: 1.01-1.28, P=0.042) for overall BC risk, 1.15 (95%CI: 0.95-1.41, P=0.160) for ER+ BC risk, and 1.17 (95%CI: 0.95-1.44, P=0.133) for ER- BC risk. The ORs for developing BC by percentiles of the PRS, relative to women in the middle quintile, showed weak linear trend. The discriminative accuracy of the PRS, as measured by the C-statistic, was 0.524 (95% CI: 0.505-0.542) for overall BC, 0.511(95% CI: 0.479-0.543) for ER+ BC, and 0.513 (95% CI: 0.481-0.545) for ER- BC. There was a statistically significant interaction between PRS and age, the association between PRS and overall BC risk were stronger in two age groups (aged &lt;40 years and ≥60 years). The PRS was also more strongly associated with PR+ (OR=1.26, 95%CI: 1.01-1.58) compared to PR- (OR=1.08, 95%CI: 0.95-1.44) BC. Association between PRS and BC were similarly non-significant across different strata of family history of BC, BMI, alcohol consumption, oral contraceptive use, menopausal, ER and HER2 status.

Table 1. Performance of the 90-SNP polygenic risk score (PRS) in the GWAS in Breast Cancer in the African DiasporaPercentile of PRS (%) OR (95%CI)  Overall BC (n=1657) vs Ctrl (n=2029)ER+ BC (n=403) vs Ctrl (n=2029)ER- BC (n=374) vs Ctrl (n=2029)&lt;51.01 (0.73-1.41)1.32 (0.28-2.13)0.89 (0.51-1.55)5-100.83 (0.59-1.15)0.71 (0.40-1.26)0.63 (0.34-1.17)10-200.74 (0.57-0.95)0.69 (0.44-1.07)0.72 (0.46-1.12)20-400.97 (0.79-1.19)0.80 (0.56-1.14)0.98 (0.69-1.39)40-601.00 (ref)1.00(ref)1.00(ref)60-800.89 (0.73-1.10)0.94 (0.66-1.33)0.90 (0.63-1.28)80-901.14 (0.89-1.47)0.87 (0.56-1.34)0.90 (0.63-1.28)90-951.14 (0.82-1.58)1.54 (0.92-2.58)0.88 (0.48-1.61)&gt;951.10 (0.79-1.52)1.15 (0.67-1.99)1.34 (0.79-2.25)Note: Odds ratios are for different percentiles of the PRS relative to the middle quintile (40% to 60%). Odds ratios were adjusted for study site and the first ten eigenvectors from principal components analysis.

Conclusion: BC PRS obtained from prior GWASs conducted in Caucasian women didn't provide a comparable degree of risk stratification for African Americans. Additional studies are needed to identify SNPs specific to women of African ancestry that could provide improved risk prediction. Further studies can also combine the PRS with lifestyle/environmental factors.

Citation Format: Wang S, Qian F, Zheng Y, Ogundiran T, Ojengbede O, Zheng W, Blot W, Nathanson KL, Hennis A, Nemesure B, Ambs S, Olopade OI, Huo D. Breast cancer risk prediction using a polygenic risk score in women of African ancestry: Findings from GWAS in breast cancer in the African diaspora [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-09-02.