An innovative membrane bioreactor (MBR) system for simultaneous nitrogen and phosphorus removal

Membrane filtration was integrated with a post-denitrification process to form an innovative membrane bioreactor (MBR) system for effective organic degradation and nutrient (N and P) removal. The system comprised of an aerobic tank, an anoxic tank, an intermediate sedimentation tank, and a membrane filtration tank. The sedimentation tank functioned not only as a rough settler for sludge–water separation before membrane filtration but also as an anaerobic chamber for P release. While half of the influent flowed into the aerobic tank, the other half was fed into the anoxic tank to favor the proliferation of phosphorus accumulating organisms (PAOs). The experiment was conducted continuously for about 430 days. With a short overall treatment time of less than 10 h for municipal wastewater, the MBR-based process could achieve the total organic carbon, total nitrogen, and total phosphorus removals of around 94%, 85%, and 87%, respectively. The growth and activity of PAOs in the MBR system were evidenced by the significant P release in the anaerobic chamber followed by the luxury P uptake in the membrane tank. With the DAPI and PAO_mix probe staining, the increases of PAOs and polyhydroxybutyrate (PHB) in sludge during the experiment were well observed under the fluorescent microscope.     

GPS项圈系统在野生动物管理与监测中的应用

野生动物管理与监测是生物多样性保护工作的重要内容。而监测手段决定了保护工作中收集数据的质量和数量。收集动物活动位点数据是野生动物管理与监测中的一项重要工作,可通过样线法收集动物活动痕迹(实体)位点或采用无线电遥测获取动物的活动位点等,采用这些位点数据可以研究野生动物种群数量、家域、运动、栖息地利用和选择等。通过给野生动物佩戴GPS项圈,利用GPS项圈系统进行定位记录其活动位点,较前述常规方法更为便利,能高效地收集大量高质量位点,这种方法可以为野生动物的管理与生物多样性保护提供更为可靠的数据基础。     

Protoporphyrin IX regulates peripheral benzodiazepine receptor associated protein 7 (PAP7) and divalent metal transporter 1 (DMT1) in K562 cells

BackgroundProtoporphyrin IX (PP IX), the immediate precursor to heme, combines with ferrous iron to make this product. The effects of exogenous PP IX on iron metabolism remain to be elucidated. Peripheral-type benzodiazepine receptor (PBR) is implicated in the transport of coproporphyrinogen into the mitochondria for conversion to PP IX. We have demonstrated that PBR-Associated Protein 7 (PAP7) bound to the Iron Responsive Element (IRE) isoform of divalent metal transporter 1 (DMT1). PP IX and PAP7 are ligands for PBR, thus, we hypothesized that PAP7 interact with PP IX via PBR.MethodsWe have examined in K562 cells, which can be induced to undergo erythroid differentiation by PP IX and hemin, the effects of PP IX on the expression of PAP7 and other proteins involved in cellular iron metabolism, transferrin receptor 1 (TfR1), DMT1, ferritin heavy chain (FTH), c-Myc and C/EBPα by western blot and quantitative real time PCR analyses.ResultsPP IX significantly decreased mRNA levels of DMT1 (IRE) and (non-IRE) from 4 h. PP IX markedly decreased protein levels of C/EBPα, PAP7 and DMT1. In contrast, hemin, which like PP IX also induces K562 cell differentiation, had no effect on PAP7 or DMT1 expression.ConclusionWe hypothesize that PP IX binds to PBR displacing PAP7 protein, which is then degraded, decreasing the interaction of PAP7 with DMT1 (IRE) and resulting in increased turnover of DMT1.General significanceThese results suggest that exogenous PP IX disrupts iron metabolism by decreasing the protein expression levels of PAP7, DMT1 and C/EBPα.     

高寒地区大嘴乌鸦春季集群与活动规律

在2004年春季,对高寒地区大嘴乌鸦（Corvus）的集群与活动规律进行了调查研究,共设置了35个有代表性的样线。大嘴乌鸦的集群大小以小规模为主,特别是以配对的形式进行繁殖活动（占46％）,平均每群（±SD）1．9±1．1只。大嘴乌鸦栖息的生境类型主要划分为电线杆生境、住宅区生境、土堆．矮桩生境、树林生境和草地生境等,其中大嘴乌鸦在住宅区生境、土堆-矮桩生境中的集群具有多样化的形式。显示出它们特有的反捕食策略和取食特性。在大嘴乌鸦3种主要的活动中,觅食行为主要集中在中午一段时间（12：00-14：00）,飞行行为高峰在下午（16：00-17：00）,上午活动比例最高的是停息行为（07：00～12：00）。这些都说明了它们长期地对高寒环境的适应性。     

Upregulation of PBR mRNA expression in human neuroblastoma cells by flavonoids

To investigate the putative mediation of peripheral benzodiazepine receptor (PBR) in the cytotoxicity of flavonoids, in this study, modulatory effects of several flavonoids on the lipid peroxide (LPO) production and PBR mRNA expression of human neuroblastoma cells were observed. Elevated levels of peroxidated products in cancer cells may activate pro-apoptotic and anti-proliferative signaling pathways. Treatment of 10(-6) M 4'-chlorodiazepam and PK 11195 ligands of the PBR for 6 days enhanced the generation of LPO of the human neuroblastoma cells. Several flavonoids, well-known cytotoxic substances, potentiated the enhancement of LPO production by PBR ligands. Treatment of 10(-6) M flavonoids for 6 days elevated the expression of PBR mRNA in cells. These findings indicate that the potential of flavonoids to induce apoptosis in cancer cells is strongly associated with their PBR-inducing properties, thereby providing a new mechanism by which polyphenolic compounds may exert their cancer-preventive and anti-neoplastic effects.     

Assessment of a bioaugmentation strategy with polyphosphate accumulating organisms in a nitrification/denitrification sequencing batch reactor

Different alternative configurations and strategies for the simultaneous biological removal of organic matter and nutrients (N and P) in wastewater have been proposed in the literature. This work demonstrates a new successful strategy to bring in enhanced biological phosphorus removal (EBPR) to a conventional nitrification/denitrification system by means of bioaugmentation with an enriched culture of phosphorus accumulating organisms (PAO). This strategy was tested in a sequencing batch reactor (SBR), where an 8 h configuration with 3 h anoxic, 4.5 h aerobic and 25 min of settling confirmed that nitrification, denitrification and PAO activity could be maintained for a minimum of 60 days of operation after the bioaugmentation step. The successful bioaugmentation strategy opens new possibilities for retrofitting full-scale WWTP originally designed for only nitrification/denitrification. These systems could remove P simultaneously to COD and N if they were bioaugmented with waste purge of an anaerobic/aerobic SBR operated in parallel treating part of the influent wastewater.     

Effect of nitrite from nitritation on biological phosphorus removal in a sequencing batch reactor treating domestic wastewater

Although nitrite effect on enhanced biological phosphorus removal (EBPR) has been previously studied, very limited research has been undertaken about the effect of nitrite accumulation caused by nitritation on EBPR. This paper focused on nitrite effect from nitritation on EBPR in a sequencing batch reactor treating domestic wastewater. Results showed that nitrite of below 10 mg/L did not inhibit P-uptake and release; whereas EBPR deterioration was observed when nitrite accumulation reached 20 mg/L. Due to P-uptake prior to nitritation, nitrite of 20 mg/L has no effect on aerobic P-uptake. The main reason leading to EBPR deterioration was the competition of carbon source. Batch tests were conducted to investigate nitrite effect on anaerobic P-release. Under sufficient carbon source, nitrite of 30 mg/L had no impact on poly-β-hydroxyalkanoate (PHA) storage; contrarily, under insufficient carbon source, denitrifiers competing for carbon source with phosphorus accumulating organisms resulted in decrease of PHA synthesis and P-release.     

Optimization of free ammonia concentration for nitrite accumulation in shortcut biological nitrogen removal process

A shortcut biological nitrogen removal (SBNR) utilizes the concept of a direct conversion of ammonium to nitrite and then to nitrogen gas. A successful SBNR requires accumulation of nitrite in the system and inhibition of the activity of nitrite oxidizers. A high concentration of free ammonia (FA) inhibits nitrite oxidizers, but unfortunately decreases the ammonium removal rate as well. Therefore, the optimal range of FA concentration is necessary not only to stabilize nitrite accumulation but also to achieve maximum ammonium removal. In order to derive such optimal FA concentrations, the specific substrate utilization rates of ammonium and nitrite oxidizers were measured. The optimal FA concentration range appeared to be 5–10 mg/L for the adapted sludge. The simulated results from the modified inhibition model expressed by FA and ammonium/nitrite concentrations were shown very similar to the experimental results.     

Simultaneous removal of carbon and nitrogen from municipal-type synthetic wastewater using net-like rotating biological contactor (NRBC)

The treatment of municipal-type synthetic wastewater was carried out using a three stages net-like rotating biological contactor (NRBC). The results indicated that, compared with conventional rotating biological contactor (RBC), NRBC have several advantages, such as quick start-up, high biomass concentration and can handle high organic loading rates. The COD and total nitrogen removal rates achieved were 78.8–89.7% and 40.2–61.4%, respectively, in aerobic treatment of low COD municipal-type wastewater at hydraulic retention times (HRT) from 5 to 9 h. The COD removal rate achieved 80–95% when organic loading varied between 16 and 40 gCOD/m² d. A large amount of nematodes were found in the NRBC system, which made the NRBC system produce relatively low amounts of waste sludge, due to their grazing.     

肿瘤血管靶向药物的研究进展

肿瘤血管在实体瘤的发生发展中具有重要的作用,靶向肿瘤血管的新药研发已成为一个热点领域.抗肿瘤血管的治疗策略分为肿瘤新生血管生成抑制剂（tumor angiogenesis inhibitor,TAI）和肿瘤血管靶向药物（vascular targeting agents,VTAs）两方面的研究.肿瘤新生血管生成抑制剂旨在抑制肿瘤新生血管生成的过程,而肿瘤血管靶向药物则是通过快速而有选择性地破坏肿瘤血管功能,使肿瘤血供受阻,导致肿瘤坏死.VTA类药物分为两类：一是小分子抑制剂（small molecule agents）,利用肿瘤血管和正常组织血管存在的差别选择性地破坏肿瘤血管;另一种是生物制剂（biological agents）,借助能够特异结合肿瘤血管的配体将毒素、凝血诱导剂、凋亡诱导分子等运送到肿瘤血管,引起血管阻塞使肿瘤坏死.     

狗小肠部分切除对移行性综合肌电的影响

将9只狗的小肠总长度的30％,50％及75％的上端分别切除,观察其对移行性综合肌电(MMC)发生规律和红霉素诱发MMCⅢ相的影响。结果发现,所有小肠部分切除的狗,残余小肠的慢波节律均较小肠完整时相应部位明显减慢;75％上端小肠切除的狗,MMC活动消失。小肠完整的狗,静脉注射红霉素均能使MMCⅢ相提前发生;30％上端小肠切除的狗,红霉素仅在一半的实验中可诱发MMCⅢ相,50％及75％上端切除后,红霉素不能诱发MMCⅢ相。但静脉注射吗啡后在所有动物模型上均能诱发MMCⅢ相。提示小肠MMC的周期活动需要空肠以上小肠的存在,红霉素仅在小肠上端能诱发MMCⅢ相。     

中华根瘤菌NP1氨单加氧酶基因的克隆与功能鉴定

以中华根瘤菌NP1(Sinorhizobium sp.NP1)为原始菌株,通过同源克隆与Tail-PCR方法,获得1089bp的氨单加氧酶基因(amo)全长序列.该基因编码362个氨基酸,其二级结构与Sinorhizobium meliloti1021AMO的二级结构相似,该蛋白有9个跨膜区段.以自杀穿梭质粒pJQ200SK为原始载体,构建NP1amo基因敲除质粒pJQ200SK-amo-Tc.采用三亲本杂交的方法将该质粒转入原始菌株NP1中,获得amo基因敲除菌株NP1∷amo.通过本贝洛氏(Berthelot)法对氨氮进行测定,发现NP1∷amo的脱氮效率比原始菌株NP1下降约35%.该结果表明,本实验中所克隆的氨单加氧酶基因为脱氮关键酶基因.