COD/TP比及NO_2^--N/TP对短程反硝化聚磷的影响

污水中COD/TP比和NO2--N/TP比对A/A/OSBR反硝化聚磷工艺运行有重要的影响。实验结果表明:随着COD/TP比值的增加,厌氧释磷增加、厌氧释磷速率提高。但当COD/TP比值为28.5时,过剩的碳源进入缺氧段,反硝化菌利用外碳源消耗,抑制了缺氧吸磷过程;当COD/TP比值为21时,合成的PHB不足,缺氧吸磷效率下降,而且长期在较低COD/TP比条件下运行,激发了聚糖菌与聚磷菌的竞争,聚磷菌处于竞争的劣势,反硝化聚磷能力最终消失;当COD/PO43--P为25时,短程反硝化聚磷效果最佳。NO2--N/TP比与COD/TP的比值相关联,在COD/TP=25的条件下,合适的NO2--N/TP比为3。当NO2--N/PO43--P为5时,SBR上一周期剩余的NO2-会影响厌氧释磷过程。当NO2--N/TP为1.8时,NO2-不足,会使反硝化聚磷过程不完全。

NO_2^--N对反硝化除磷系统运行效能的影响

通过改变反硝化聚磷菌(DPAOs)的电子受体类型,考察了不同浓度的NO_2--N作为电子受体时其对反硝化除磷系统运行效能的影响。试验结果表明,在合适的进水NO_2--N浓度范围内,DPAOs经过驯化后能够以NO_2--N为电子受体进行反硝化除磷反应;在短程反硝化除磷系统中,NO_2--N的抑制浓度为30 mg·L-1,当系统进水中的NO_2--N浓度大于30 mg·L-1时,系统的除磷作用及PHA的合成作用均会受到抑制,系统的反硝化效果和COD去除效果亦会出现较为明显的变化,究其原因可能与系统中GAO开始占据优势有关;在短程反硝化除磷系统中,厌氧释磷量与缺氧吸磷量有着良好的线性关系,而对于NO_2--N对DPAOs的抑制机理,笔者将在后续试验中进行深入分析和探究。

CYP24A1 inhibition facilitates the anti-tumor effect of vitamin D3 on colorectal cancer cells

AIM:The effects of vitamin D3 have been investigated on various tumors, including colorectal cancer (CRC). 25-hydroxyvitamin-D3-24-hydroxylase (CYP24A1), the enzyme that inactivates the active vitamin D3 metabolite 1,25-dihydroxyvitamin D3 (1,25-D3), is considered to be the main enzyme determining the biological halflife of 1,25-D3. During colorectal carcinogenesis, the expression and concentration of CYP24A1 increases significantly, suggesting that this phenomenon could be responsible for the proposed efficacy of 1,25-D3 in the treatment of CRC. The aim of this study was to investigate the anti-tumor effects of vitamin D3 on the human CRC cell line Caco-2 after inhibition of the cytochrome P450 component of CYP24A1 activity. METHODS:We examined the expression of CYP24A1 mRNA and the effects of 1,25-D3 on the cell line Caco-2 after inhibition of CYP24A1. Cell viability and proliferation were determined by means of sulforhodamine-B staining and bromodeoxyuridine incorporation, respectively, while cytotoxicity was estimated via the lactate dehydrogenase content of the cell culture supernatant. CYP24A1 expression was measured by realtime reverse transcription polymerase chain reaction. A number of tetralone compounds were synthesized to investigate their CP24A1 inhibitory activity. RESULTS:In response to 1,25-D3, CYP24A1 mRNA expression was enhanced significantly, in a time- and dose-dependent manner. Caco-2 cell viability and proliferation were not influenced by the administration of 1,25-D3 alone, but were markedly reduced by coadministration of 1,25-D3 and KD-35, a CYP24A1-inhibiting tetralone. Our data suggest that the mechanism of action of co-administered KD-35 and 1,25-D3 does not involve a direct cytotoxic effect, but rather the inhibition of cell proliferation. CONCLUSION:These findings demonstrate that the selective inhibition of CYP24A1 by compounds such as KD-35 may be a new approach for enhancement of the anti-tumor effect of 1,25-D3 on CRC.

The Inhibition Effect of Tert-Butyl Alcohol on the TiO_2 Nano Assays Photoelectrocatalytic Degradation of Different Organics and Its Mechanism

The inhibition effect of tert-butyl alcohol(TBA), identified as the·OH radical inhibitor, on the TiO_2 nano assays(TNA) photoelectrocatalytic oxidation of different organics such as glucose and phthalate was reported. The adsorption performance of these organics on the TNA photoelectrode was investigated by using the instantaneous photocurrent value, and the degradation property was examined by using the exhausted reaction. The results showed that glucose exhibited the poor adsorption and easy degradation performance, phthalate showed the strong adsorption and harddegradation, but TBA showed the weak adsorption and was the most difficult to be degraded. The degradation of both glucose and phthalate could be inhibited evidently by TBA. But the effect on glucose was more obvious. The different inhibition effects of TBA on different organics could be attributed to the differences in the adsorption and the degradation property. For instance, phthalate of the strong adsorption property could avoid from the capture of·OH radicals by TBA in TNA photoelectrocatalytic process.

Lentivirus mediated shRNA interference targeting MAT2B induces growth-inhibition and apoptosis in hepatocelluar carcinoma

AIM: To investigate the effects of lentivirus vector mediated short hairpin RNA interference targeting methionine adenosyltransferase 2β gene (LV-shMAT2B) on hepatocelluar carcinoma (HCC) cells. METHODS: We constructed four plasmids of RNA interference targeting the MAT2B gene. After LV-shMAT2B was transfected with L-02 cells and two kinds of HCC cells, cell viability and proliferation were measured with MTT and [3H]thymidine assays respectively. Flow cytometry was used to assess cell apoptosis. The level of S-adenosyl methionine (SAMe) in HepG2 cells was evaluated. The expressions of cyclin D1, cyclin D2, bcl-xL and bcl-xS were detected with western blot. RESULTS: We constructed LV-shMAT2B successfully. LV-shMAT2B was safe for human normal liver cells. LV-shMAT2B caused dramatic reduction in proliferation compared with controls in HCC cells Bel-7402 (P = 0.054) and HepG2 (P = 0.031). Flow cytometry analysis showed that cell apoptosis caused by LV-shMAT2B was greater in HCC cells Bel-7402 and HepG2 than in control induced by scrambled siRNA (P = 0.047), but apoptosis rates in L-02 induced by LV-shMAT2B and scrambled siRNA respectively had no significant difference. Moreover, LV-shMAT2B significantly suppressed expression of MAT2B leading to growth-inhibition effect on HCC cells by down-regulating cyclin D1. Apoptosis induced by LV-shMAT2B was involved indown-regulating bcl-xL and up-regulating bcl-xS. CONCLUSION: LV-shMAT2B can induce cell apoptosis and growth-inhibition in HCC cells. MAT2B may be a therapy target in HCC in the future.

Dual HER2 inhibition strategies in the management of treatment-refractory metastatic colorectal cancer:History and status

Human epidermal growth factor receptor 2(HER2) signaling pathway activation has been identified as a contributor to de novo or acquired resistance to epidermal growth factor receptor(EGFR) inhibitors in a small subset of patients with metastatic colorectal cancer(mCRC). Dual anti-HER2-targeted treatment exhibits strong antitumor activity in preclinical models of HER2-positive mCRC, supporting its testing in clinical trials. The HERACLES trial at four Italian academic cancer centers has confirmed the effectiveness of dual blockage of HER2 with trastuzumab plus lapatinib in patients with heavily pretreated HER2-positive mCRC, refractory to the anti-EGFR antibodies cetuximab or panitumumab. Here, we reviewed the preclinical studies exploring the role of HER2 signaling in the development of anti-EGFR therapy resistance and discussed the status of clinical trials assessing the activity of HER2 inhibitors in this setting.

Biological Evaluation of a Novel 2’-Fluoro Derivative 5-Azacytidine as a Potent DNA Methyltransferase Inhibitor

Background: DNA methyltransferases (DNMTs) are key epigenetic regulatory enzymes involved in the expression of many genes and are considered as an attractive target for cancer treatment, especially hematological malignancies. Therefore, promising DNMT inhibitors characterized by low toxicity, target activity and high selectivity are crucial for the development of new cancer therapy and research on the inhibitory mechanism. We had previously demonstrated that the novel 2’-fluoro-2’-deoxy-arabinofuranosyl 5-azacytosine nucleoside (2’F-araAC) showed high antiproliferative activity in vitro and increased hydrolytic stability compared to the known agents like azacitidine and decitabine. Objective: The objective of the present study was to investigate the effect of novel 2’F-araAC as potent anti-leukemia agent and DNMTs inhibitor on nuclear extract of the HCT-116 human colorectal cell line and P388 and L1210 mouse leukemia cell lines. Methods: The DNMTs activity was evaluated using the fluorometric DNMT Activity Quantification Kit (Abcam) and were reported as the percentage of control. Nuclear proteins were extracted from HCT-116 cell line using the Nuclear Extraction Kit (Abcam). To explore the mechanism of anti-leukemic activity of 2’F-araAC, cell cycle and apoptosis analyses were performed on P388 and L1210 cell lines. Results: It has been shown that the DNMTs activity was significantly reduced at 1 and 10 µM of 2’F-araAC compared to controls. Moreover, 2’F-araAC can induce G2/M cell cycle arrest and apoptosis in P388 and L1210 mouse leukemia cell lines as shown by flow cytometry method. Apoptosis was 54.53% and 43.35% for 2’F-araAC vs. 2.88% and 5.25% for the control P388 and L1210 cell lines, respectively. Conclusions: Thus, our study presents a new and promising compound to further develop new epigenetic regulators to be used as antitumor agents.

Inhibition of Coke Formation in Cracking of 2-Methylpentane on USHY by Addition of Steam

The effect of steam dilution on the formation of coke and minor products in 2-methylpenatne cracking on ultra stable HY at 673 K has been studied. The results show that steam dilution suppresses the formation of coke and minor aromatic products, but enhances the H/C atomic ratio of coke and the production of di-olefins. This and other evidences suggest that steam dilution enhances the desorption of coke precursors, diolefinic ions and cyclic ions, by inhibiting the further pathological reactions to produce aromatics and polyaromatics. These insights into the chemistry underlying coke formation in hydrocarbon cracking on solid acid catalysts can potentially be applied to the development of additives which inhibit coke formation and control catalyst deactivation.

Design of highly active and durable oxygen evolution catalyst with intrinsic chlorine inhibition property for seawater electrolysis

High-efficiency seawater electrolysis is impeded by the low activity and low durability of oxygen evolution catalysts due to the complex composition and competitive side reactions in seawater.Herein,a heterogeneousstructured catalyst is constructed by depositing NiFe-layered double hydroxides(NiFe-LDH)on the substrate of MXene(V_(2)CT_(x))modified Ni foam(NF),and abbreviated as NiFe-LDH/V_(2)CT_(x)/NF.As demonstrated,owing to the intrinsic negative charge characteristic of V_(2)CT_(x),chlorine ions are denied entry to the interface between NiFeLDH and V_(2)CT_(x)/NF substrate,thus endowing NiFe-LDH/V_(2)CT_(x)/NF catalyst with high corrosion resistance and durable stability for 110 h at 500 mA cm^(-2).Meanwhile,the two-dimensional structure and high electrical conductivity of V_(2)CT_(x) can respectively enlarge the electrochemical active surface area and guarantee fast charge transfer,thereby synergistically promoting the catalytic performance of NiFe-LDH/V_(2)CT_(x)/NF in both deionized water electrolyte(261 m V at 100 m A cm^(-2))and simulated seawater electrolyte(241 mV at 100 mA cm^(-2)).This work can guide the preparation of oxygen evolution catalysts and accelerate the industrialization of seawater electrolysis.

Synthesis of Fluorinated Heterobicyclic Nitrogen Systems Containing 1,2,4-Triazine Moiety as CDK2 Inhibition Agents

New fluorine substituted heterobicyclic nitrogen system as imidozolopyrimidines (2,3), pyrimido- 1,2,4-triazinones (4-7), 1,2,4-triazinyl-1,2,4-triazine (12-16), 1,2,4-triazinyl-1,2,4-triazinones (14-17) and substituted thiobarbituric acids (19-20), have been synthesized using the reaction of 3- amino-5,6-di (4'-fluorophenyl)-1,2,4-triazine (1) with α,β–bifunctional compounds. Structures of the title compounds were characterized by UV, IR, 1H/13C-NMR and mass spectrometric method. The studied compounds were tested for CDK2 inhibiting activity in DNA damage, as well as in vitro anti-tumor activity.

Effects of TSH inhibition after total thyroidectomy on Tg, VEGF, TSGF, CD44V6, sIL-2R and T lymphocyte subsets in patients with differentiated thyroid carcinoma

Objective:To study the effects of TSH inhibition after total thyroidectomy on Tg, VEGF, TSGF, CD44V6, sIL-2R and T lymphocyte subsets in patients with differentiated thyroid carcinoma (DTC).Methods: A total of 100 patients with DTC in our hospital from January 2014 to January 2017 were enrolled in this study. The subjects were divided into the control group (n=50) and the treatment group (n=50) randomly. The control group was treated with thyroid hormone replacement therapy, the treatment group was treated with levothyroxine sodium oral therapy, the two groups were treated for 1 week. The serum Tg, VEGF, TSGF, CD44V6, sIL-2R and peripheral blood CD3+, CD4+, CD8+ of the two groups before and after treatment were compared.Results:There were no significant differences of the serum Tg, VEGF, TSGF, CD44V6, sIL-2R of the two groups before treatment. The serum Tg, VEGF, TSGF, CD44V6, sIL-2R of the two groups after treatment were significantly lower than before treatment, and that of the treatment group after treatment were significantly lower than the control group. There were no significantly differences of the peripheral blood CD3+, CD4+, CD8+ of the two groups before treatment. The peripheral blood CD3+, CD4+ of the two groups after treatment were significantly higher than before treatment, the peripheral blood CD8+ of the two groups after treatment were significantly lower than before treatment, and that of the treatment group after treatment were significantly better than the control group.Conclusion:TSH inhibition after total thyroidectomy for patients with DTC can reduce the serum Tg, VEGF, TSGF, CD44V6, sIL-2R levels, improve the cellular immunity function, and it was worthy clinical application.

Antidiabetic effect of Chrysophyllum albidum is mediated by enzyme inhibition and enhancement of glucose uptake via 3T3-L1 adipocytes and C2C12 myotubes

Objective:To investigate the in vivo and in vitro antidiabetic potential of Chrysophyllum albidum.Methods:The effects of oral treatment with hydro-ethanolic extract(125,250 and 500 mg/kg)of the stem bark of Chrysophyllum albidum and glibenclamide for 21 d on glucose level,serum enzyme markers for liver function,lipid profile,total protein,serum urea,serum creatinine,and body weight were evaluated in experimental diabetic rats administered with 45 mg/kg of streptozotocin.In vitro assays including glucose uptake in C2 C12 cells and 3 T3-L1 adipose tissues,α-glucosidase andα-amylase inhibition were employed to evaluate the possible mechanism of hypoglycemic action of the extract.DPPH and nitric oxide radical antioxidant activity of the extract was also measured.Results:The increased levels of blood glucose,triglycerides,lowdensity lipoprotein,total cholesterol,serum aspartate,and alanine transaminases,creatinine,and urea in the diabetic animals were reduced significantly(P<0.01)after treatment with Chrysophyllum albidum extract.The decreased total protein and high-density lipoprotein concentrations were normalized after treatment.In addition,the extract significantly(P<0.01)increased the transport of glucose in 3 T3-L1 cells and C2 C12 myotubes and exhibited considerable potential to inhibitα-amylase andα-glucosidase.It also demonstrated potent antioxidant action by scavenging considerably DPPH and nitric oxide radicals.Conclusions:Chrysophyllum albidum stem bark extract exhibits considerable antidiabetic effect by stimulating glucose uptake and utilization in C2 C12 myotubes and 3 T3-L1 adipocytes as well as inhibiting the activities ofα-amylase andα-glucosidase.

Roles of 5-HT2 receptors in effects of DOM,ketamine and methamphetamine on prepulse inhibition in Sprague Dawley rats

OBJECTIVE Prepulse inhibition(PPI)of the acoustic startle response provides a measure of sensorimotor gating system mecha⁃nisms,which is known to be impaired in schizo⁃phrenia patients.We assessed the effects of the 5-HT2A/2C receptor agonist(±)2,5-dimethoxy-4-methylamphetamine(DOM),the NMDA receptor antagonist ketamine,the dopamine receptor ago⁃nist methamphetamine(Meth)on PPI and the startle magnitude in SD rats.METHODS AND RESULTS Systemic administration of the three compounds all dose-dependently reduced PPI.However,as far as startle magnitude,only DOM at the doses of 3 mg·kg-1 reduced that,while both ketamine and Meth did not change the startle magnitudes.Furthermore,to determine whether 5-HT2A receptor mediate this effect,the non-spe⁃cific 5-HT2 receptor antagonist cyproheptadine,specific 5-HT2A receptor antagonist ketanserin and specific 5-HT2C receptor antagonist SB242084 were tested.Cyproheptadine,ketan⁃serin and SB242084 did not alter startle ampli⁃tude by themselves in SD rats and only ketanserin slightly increased PPI at higher dose(3 mg·kg-1).PPI impairment induced by DOM was restored by pretreatment of cyproheptadine(1 mg·kg-1)and ketanserin(1 mg·kg-1),while not by pretreat⁃ment of SB242084(1 mg·kg-1).Damage of PPI induced by ketamine and Meth was not reversed by cyproheptadine(1 and 5 mg·kg-1).CONCLU⁃SION The receptor mechanisms underlying the disruption of PPI caused by DOM,ketamine and Meth were different from each other,at least 5-HT2A receptor was not the junction receptor for which the three chemicals acted.

S^(2-)/NO_3^--N对硫自养反硝化与厌氧氨氧化耦合脱氮除硫启动的影响

为寻求经济、有效的同步脱氮除硫工艺,采用HABR(复合式厌氧折流板反应器),接种厌氧氨氧化活性污泥,以人工模拟废水为研究对象,在进水p H为8.0、温度为(32±1)℃、HRT为6.5 h的条件下,调整进水S2-/NO3--N〔n(S2-)∶n(NO3--N)〕分别为2.0∶5、3.5∶5、5.0∶5、6.5∶5,研究其对硫自养反硝化和厌氧氨氧化耦合工艺启动的影响,试验连续进行了54 d.结果表明:当S2-/NO3--N<1时,S2-的供应量相对不足,导致硫自养反硝化生成的NO2--N量不足,进而影响后续厌氧氨氧化效果,NH4+-N去除率较低,平均值为53.5%,同时剩余NO3--N继续氧化硫自养反硝化生成的S0,致使出水中ρ(SO42-)增大;当S2-/NO3--N=1时,S2-供应量充足,硫自养反硝化生成NO2--N量最大,厌氧氨氧化效果最好,NH4+-N去除率最高,平均值为65.1%;当S2-/NO3--N>1时,S2-过量,S2-去除率下降.试验通过控制S2-/NO3--N,在HABR内成功实现了硫自养反硝化和厌氧氨氧化耦合工艺启动,NH4+-N、S2-、NO3--N最大去除率分别为74.3%、99.0%、99.5%,S2-/NO3--N=1为最佳比例.

NO_2^-—N对铜绿微囊藻生理特性的影响

采用藻类生物测试标准方法研究了不同NO2--N初始浓度条件下铜绿微囊藻(Microcystis aeruginosa)的生长及生理变化.结果表明,相对BG11(NO2--N初始浓度为0)培养基,低初始NO2--N浓度(1,10mg/L)条件下铜绿微囊藻生长良好;高NO2--N初始浓度(20,30,40mg/L)条件下藻生长缓慢甚至停滞.NO2--N初始浓度由10mg/L到30mg/L,亚硝酸还原酶(NiR)活性和过氧化氢酶(CAT)活性呈增加趋势;在NO2--N初始浓度分别为20～30mg/L和20～40mg/L时,叶绿素a(Chl-a)含量和丙二醛(MDA)含量随NO2--N浓度增大而逐渐升高;在初始NO2--N浓度0,1,10,20,30mg/L条件下硝酸还原酶(NR)没有明显变化.这表明,铜绿微囊藻在NO2--N初始浓度10,20,30mg/L条件下能维持一定的生长,主要由于藻叶绿素含量的增加,NiR活性和防止细胞过氧化的酶CAT活性的提高所致.

MLSS和温度对以NO2--N为电子受体的反硝化除磷的影响研究

对经过长期培养驯化的以NO2^--N为电子受体的反硝化聚磷污泥进行静态烧杯试验，研究了MLSS和温度等因素对反硝化除磷系统处理效果的影响。结果表明，MISS浓度过高或过低都会影响系统对PO4^3--P的去除效果，MLSS为4000mg／L左右时，系统的除磷效果最佳。系统运行的最佳温度为20℃左右，此时系统对PO4^3--P的去除率达到了89．14％。

S^(2-)/NO_3^--N对硫氮同步去除的影响

采用UASB反应器,研究不同S^(2-)/NO_3^--N对硫化物、氨氮和硝态氮同步去除的影响。结果表明,S^(2-)/NO_3^--N在1/1、9/8、5/4、3/2四个阶段反应器稳定运行时,硫化物去除率为80%~100%,氨氮去除率为93%~99%,硝态氮去除率基本稳定在96%左右,脱氮除硫效果良好。在S^(2-)/NO_3^--N为9/8的最佳工艺条件下,硫化物去除率为100%,氨氮去除率达到99%,硝态氮去除率达到96%。同时探讨了S^(2-)/NO_3^--N影响硫氮同步去除的机理。

包膜肥料对水稻土壤渗滤液中NO2^--N、NO3^--N、NH4^＋-N的影响

通过有机玻璃土柱盆栽试验,研究了包膜肥料在水稻不同生育期对不同深度土层的土壤渗滤液中NO2--N、NO3--N、NH4+-N含量的影响。结果表明,土壤渗滤液中NO2--N、NO3--N、NH4+-N质量浓度随着水稻的生长逐渐降低;在水稻分蘖期和拔节期,随着土壤深度的增加NO2--N、NO3--N含量呈现先减小后增大的趋势,NH4+-N含量呈现先增大再减小再增大的趋势;在水稻抽穗期和成熟期,NO2--N、NO3--N含量呈现逐渐减小的趋势,NH4+-N含量呈现增大的趋势。在水稻生育期内与施用普通尿素UR相比,包膜肥料LP40、LPSS、SC60氮素渗滤损失总量分别降低了58.27%,46.38%,33.30%。

一例胭脂鱼亲鱼N0_2^--N急性中毒病例

在2011年胭脂鱼人工繁殖试验中,发现一例亲鱼N02--N急性中毒死亡病例,测定其96hLC50为0.9mg/L,转移至亲鱼塘后得到有效解除,测试安全浓度(SS)为0.005mg/L。胭脂鱼亲鱼N02--N急性中毒病症尚未见报道,该例亲鱼N02--N急性中毒病例的成功抢救,可为胭脂鱼生理生态、人工繁育、鱼病防治、养殖水质管理、资源保护提供参考。

CO_2浓度与N素形态对白桦幼苗NO_3^--N代谢的影响

在CO2人工气候箱(Pervical,PGC-9/2)内,用水培的方法研究了CO2浓度和NO3--N/NH4+-N对白桦幼苗NO3--N代谢的影响。结果表明:白桦幼苗根系、叶片NR活性以及叶片NO3--N、可溶性蛋白含量均随NO3--N供应比例和CO2浓度的增加而有所增加。在NO3--N/NH4+-N≥50/50时,CO2浓度倍增显著提高了白桦幼苗根系和叶片NR活性。CO2浓度倍增显著提高了白桦幼苗叶片NO3--N含量,且促进程度随营养液NO3--N比例的增加而加大。除NO3--N/NH 4+-N为100/0外,CO2浓度倍增并未显著提高白桦幼苗叶片的可溶性蛋白含量。CO2浓度与N素形态的交互作用对白桦幼苗根系、叶片NR活性以及叶片NO3--N含量的影响显著。