Influence of pH on short-cut denitrifying phosphorus removal

Through a series of experiments using denitrifying phosphorus-accumulating sludge in sequencing batch reactors （SBRs）, the variations of the intracellular polymers during the anaerobic phosphorus release process at different pH values were compared, the probable reasons for different performances of phosphorus removal were examined, and system operations in a typical cycle were investigated. The results show that the phosphorus removal rate was positively correlated with pH values in a range of 6.5-8.5. When the pH value was 8.0, the anaerobic phosphorus release rate and anoxic phosphorus uptake rate of the activated sludge were 20.95 mg/（g, h） and 23.29 mg/（g, h）, respectively; the mass fraction of poly-13-hydroxybutyrate （PHB） increased to 62.87 mg/g under anaerobic conditions; the mass fraction of polyphosphate was 92.67 mg/g under anoxic conditions; and the effluent concentration of total phosphorus （TP） was 1.47 mg/L. With the increase of pH, the mass fraction of acetic acid and PHB also increased, and the absorption rate of acetic acid was equal to the disintegration rate of polyphosphate. When the pH value was above 8.0, biological phosphorus removal was achieved by chemical phosphorus precipitation, and the phosphorus removal rate decreased.

Epigallocatechin-3-gallate attenuates lipopolysaccharideinduced inflammation in human retinal endothelial cells

AIM:To investigate the mechanism underlying the anti-inflammatory effects of epigallocatechin-3-gallate(EGCG)in lipopolysaccharide(LPS)-stimulated human retinal endothelial cells(HRECs).METHODS:HRECspre-treatedwithEGCG(0-100μmol/L)were stimulated with LPS(250 ng/mL).Levels of tumor necrosis factor alpha(TNF-α),vascular endothelial growth factor(VEGF),monocyte chemotactic protein-1(MCP-1)and nitric oxide(NO)in the supernatants were determined by enzyme-linked immunosorbent assay(ELISA)and Griess assay.The protein expression of phosphorylated extracellular signal-regulated kinase(ERK)1/2 and p38 mitogen-activated protein kinases(p38)were determined by Western blot analysis.RESULTS:EGCG pre-treatment significantly inhibited the secretion of TNF-α,VEGF,MCP-1 and NO in LPSstimulated HRECs.Moreover,EGCG effectively attenuated LPS-induced activation and phosphorylation of ERK1/2 and p38 in HRECs in a dose-dependent manner.CONCLUSION:EGCG exhibited inhibitory effects on LPS-induced pro-inflammatory cytokines production by modulating ERK1/2 and p38 pathways in HRECs,suggesting EGCG as a potential candidate for antiinflammatory intervention.

Nereid's orbit based on new precise observations

A new orbit of Triton was provided by our previous work, benefitted by new Gaia Data, both in a new precise reduction of charge-coupled device observations and in the planetary ephemeris INPOP19 a.In this paper, we provide a new ephemeris for another main Neptunian satellite, Nereid. The orbit is fitted for the newest observations, including 2 075 ground-based observations during the period 1949-2018 and 83 space observations acquired by the Voyager 2 spacecraft in 1989. The dynamical model used here is consistent with that of our previous work. For the ground-based absolute observations of Nereid, the rootmean-square deviations are 0.201′′in right ascension and 0.189′′in declination. Finally, a comparison with the HORIZONS ephemeris is made and discussed.

Serum lipids and other risk factors for diabetic retinopathy in Chinese type 2 diabetic patients

Objective: To investigate the association of serum lipids and other risk factors with diabetic retinopathy (DR) in Chinese type 2 diabetic patients. Methods: Five hundred and twenty-three type 2 diabetic patients underwent ophthalmic examination by experienced retinal specialists to assess their DR. Serum lipids, including triglycerides, total cholesterol, high density lipoprotein cholesterol (HDLC), and low density lipoprotein cholesterol (LDLC), were measured using Roche automated clinical chemistry analyzers. The concentration of very low density lipoprotein cholesterol (VLDLC) was calculated based on total cholesterol, HDLC and LDLC. Hyperlipidemia was defined as a total cholesterol concentration of 6.2 mmol/L or higher or the use of lipid-lowering medications. The association of risk factors with any DR or proliferative diabetic retinopathy (PDR) was assessed using the odds ratio (OR) and its 95% confidence interval (CI), calculated from logistic regression models. Results: In multivariate logistic regression models, hyperlipidemia (OR=2.39, 95% CI: 1.02-5.66), higher VLDLC (OR=1.59, 95% CI: 1.14-2.23), and higher triglyceride (OR=1.18, 95% CI: 1.03-1.37) were associated with increased risk of DR. A longer diabetic duration was associated with increased risk of DR (P<0.0001) and PDR (P=0.002) in a dose-response manner. Higher systolic blood pressure (P=0.02) and higher serum creatinine (P=0.01) were independently associated with increased risk of DR, and female gender was associated with increased risk of PDR (P=0.03). Conclusions: Among Chinese type 2 diabetic patients, hyperlipidemia, higher VLDLC, and higher triglyceride were independently associated with increased risk of DR, suggesting control of serum lipids may decrease the risk of DR.

基于苝单酰亚胺-野尻霉素的自组装多效价糖苷酶抑制剂研究

糖尿病是糖苷酶代谢异常导致的慢性疾病.近年来多效价糖苷酶抑制剂研究为新型降糖药物的研发开辟了新的途径和策略.如何构筑多效价糖苷酶抑制剂是多效价糖苷酶抑制剂研究存在的关键科学问题.本文合成了苝单酰亚胺-野尻霉素分子PMI-DNJ,经自组装构筑了多效价糖苷酶抑制剂,其对α-甘露糖苷酶的抑制活性为1.41μM,与米格列醇和单体相比分别提高24倍和65倍,具有多价效应.PMI-DNJ对α-葡萄糖苷酶的抑制活性为10.98μM,与米格列醇和单体相比分别提高1.88倍和5.6倍.小鼠体内降糖效果显示,给药量分别为0.5和1.0 mg/kg时,PMI-DNJ在30 min时的相对降糖率分别为27.36%和30.08%,折合摩尔降糖效果,比米格列醇具有更好的降糖作用,具有多价效应.

Microstructure and magnetocaloric properties of partially crystallized Gd_(60)Co_(30)Fe_(10)amorphous alloy prepared by different solidification cooling rates

The Gd_(60)Co_(30)Fe_(10)alloy ribbons with different solidification cooling rates were prepared by modifying the melt-spinning speed of 6.0,12.5,25.0 and 50.0 m·s^(-1)·With cooling rate decreasing,the(Fe,Co)5 Gd and hcp-Gd nanocrystalline was in situ precipitated among the amorphous matrix,which resulted in the composition change of the amorphous phase.Because of the only slight amount of crystalline phase in Gd_(60)Co_(30)Fe_(10)alloys,the magnetic and magnetocaloric properties mainly depend on the amorphous phase,and all the magnetic entropy change versus temperature(|Δ|SMI-T)curves are table-like,indicating the suitability for Ericsson cycle.The magnetic transition temperature of the Gd_(60)Co_(30)Fe_(10)alloy at a melt-spinning speed of 6.0 m·s^(-1) shifted obviously to the lower value with the applied magnetic fields increasing.The peak value of magnetic entropy change(|ΔSMpk|)is 2.19 J·kg^(-1)·K^(-1)at217 K under the magnetic field change of 0-2 T,and the table-like region is 200-230 K.It was proved that the moderate reduction of the cooling rate will not deteriorate the magnetocaloric performance of the Gd_(60)Co_(30)Fe_(10)ribbons seriously.

Crack analysis in Ti-6Al-4V alloy produced by selective laser melting

Quality and property control have become one of the critical problems for the metallic parts produced by selective laser melting.In this paper,the crack spontaneously formed in the Ti-6 Al-4 V alloy by selecting laser melting is investigated.The crack is C-shape without branching in macro view.In micro view,the crack originates from and propagates toward the selective laser melting(SLM)processing defects.The crack surface topography shows that the crack is typical dimple cleavage.A few heads of martensiticα’laths appear at the bottom of the dimple.And the secondary crack nucleates and grows up near by the martensiticα’laths.A lot of spatters and cavities formed at the top surface of the SLM body and the residual stress accumulated in the SLM body is up to 640 MPa,which confirms that the SLM processing defects and the residual stress induced the origination and propagation of the crack.The research results indicate that preventing spatter and controlling residual stress are important to SLM processing.