Search

The anammox bacteria (AnAOB) have been suggested to perform dissimilatory Fe0/Fe2+-dependent nitrate reduction to ammonium (DNRA), with nitrite as intermediate. However, evidence at genetic and tra...

Anammox bacteria are chemolithotrophic organisms growing on the conversion of ammonium and nitrite with bicarbonate as the sole carbon source. Meanwhile, anammox bacteria display a metabolic versatility to sustain their metabolism. However, there is less attention on the Fe0/Fe2+-dependent autotrophic denitrification by anammox consortia. In this study, the autotrophic nitrate reduction using different valence of iron (Fe0, Fe2+ and Fe0+ Fe2+, respectively) as electron donors by anammox consortia were firstly explored in continuous feeding mode. Results revealed anammox consortia showed high adaptability to the niche wherein containing nitrate and iron. They could generate nitrite and ammonium from iron-dependent nitrate reduction, and hence support their central metabolism. During 60-days operation, the maximum nitrate and total nitrogen removal efficiency reached 88.43% and 80.77%, respectively, with coexistence of Fe0 and Fe2+. The expression of key functional genes involved in nitrate reduction (including narG, napA and nrfA) in 16S rRNA level revealed the coupling of dissimilatory nitrate reduction to nitrite, dissimilatory nitrite reduction to ammonia (DNRA), and anammox processes possibly play pivotal role in nitrogen loss under Fe0/Fe2+ condition. Meanwhile, abiotic reduction by Fe0/Fe2+ also contributed nitrate reduction to provide nitrite and ammonium for anammox consortia. Activities of two vital enzymes hydrazine dehydrogenase (HDH) and nitrate oxidoreduetase (NAR) also inferred higher microbial activities with co-existence of Fe0 and Fe2+. The present study confirms and further extends the versatile metabolisms of Anammox consortia, also it can help to circumvent the accumulation of nitrate produced by anammox process itself and increase the quality of discharge.

Obesity is becoming a global problem. Research into the detailed mechanism of adipocyte development is crucial for the treatment of excess fat. Zinc finger protein 217 plays roles in adipogenesis. However, the underlying mechanism remains unclear. Here, we demonstrated that ZFP217 knockdown prevented the mitotic clonal expansion process and caused adipogenesis inhibition. Depletion of ZFP217 increased the expression of the m6A methyltransferase METTL3, which upregulated the m6A level of cyclin D1 mRNA. METTL3 knockdown rescued the siZFP217-inhibited MCE and promoted CCND1 expression. YTH domain family 2 recognized and degraded the methylated CCND1 mRNA, leading to the downregulation of CCND1. Consequently, cell-cycle progression was blocked, and adipogenesis was inhibited. YTHDF2 knockdown relieved siZFP217-inhibited adipocyte differentiation. These findings reveal that ZFP217 knockdown-induced adipogenesis inhibition was caused by CCND1, which was mediated by METTL3 and YTHDF2 in an m6A-dependent manner. We have provided novel insight into the underlying molecular mechanisms by which m6A methylation is involved in the ZFP217 regulation of adipogenesis.

N6-methyladenosine (m6A), the most abundant internal mRNA modification in eukaryotes, plays a vital role in regulating adipogenesis. However, its underlying mechanism remains largely unknown. Here, we reveal that deletion of m6A demethylase FTO in porcine and mouse preadipocytes inhibits adipogenesis through JAK2-STAT3-C/EBPβ signaling. Mechanistically, FTO deficiency suppresses JAK2 expression and STAT3 phosphorylation, leading to attenuated transcription of C/EBPβ, which is essential for the early stage of adipocyte differentiation. Using dual-luciferase assay, we validate that knockdown of FTO reduces expression of JAK2 in an m6A-dependent manner. Furthermore, we find that m6A "reader" protein YTHDF2 directly targets m6A-modified transcripts of JAK2 and accelerates mRNA decay, which results in decreased JAK2 expression and inactivated JAK2-STAT3-C/EBPβ signaling, thereby inhibiting adipogenesis. Collectively, our results provide a novel insight into the molecular mechanism of m6A methylation in post-transcriptional regulation of JAK2-STAT3-C/EBPβ signaling axis and highlight the crucial role of m6A modification and its modulators in adipogenesis.

To achieve the simultaneous removal of NH4+-N and NO3−-N in F−-containing semiconductor wastewater by coupled S0-driven autotrophic denitrification and Anammox process, the effect of variable F− concentration on the Anammox process was investigated by batch experiments. The denitrifying ammonium oxidation (Deamox) reactor was then started-up to explore the feasibility of the coupling of Anammox and sulfur autotrophic denitrification (SADN) for the treatment of semiconductor wastewater. Short-term variation of F− concentration has an obviously effect on the activity of Anammox sludge, but didn't affect the nitrogen conversion rate. The activity of Anammox obviously decreased after long-term operation of the Deamox reactor when influent F− concentrations reached 552 mg/L. The sensitivity of Anammox bacteria to F− concentration is stronger than that of SADN bacteria. Total nitrogen removal efficiency of 98% and total nitrogen removal rate of 4.11 kg/(m3·d) were achieved in the Deamox reactor, when the F− was pre-treated by calcium ions. Moreover, the high-throughput 16S rRNA gene sequence analysis indicated that variation in F− concentrations could influence the structure and functional of microbial communities in the Deamox process. Candidatus Kuenenia, Thiobacillus and Sulfurimonas were main functional bacteria that achieved symbiotic.

Bone marrow stem cells (BMSCs) are multipotent stem cells that can regenerate mesenchymal tissues, such as adipose tissue, bone, and muscle. Recent studies have shown that N6-methyladenosine (m6A) methylation, one of the most prevalent epigenetic modifications, is involved in the development process. However, whether it plays roles in BMSC differentiation is still elusive. Here, we found that the deletion of m6A "writer" protein methyltransferase-like (METTL)3 in porcine BMSCs (pBMSCs) could promote adipogenesis and janus kinase (JAK)1 protein expression via an m6A-dependent way. Knockdown of METTL3 decreased mRNA m6A levels of JAK1, leading to enhanced YTH m6A RNA binding protein 2 (YTHDF2)-dependent JAK1 mRNA stability. We further demonstrated that JAK1 activated signal transducer and activator of transcription (STAT) 5 through regulation of its phosphorylation to bind to the promoter of CCAAT/enhancer binding protein (C/EBP) β, which could ultimately lead to a modulated adipogenic process. Collectively, our results reveal an orchestrated network linking the m6A methylation and JAK1/STAT5/C/EBPβ pathway in pBMSCs adipogenic differentiation. Our findings provide novel insights into the underlying molecular mechanisms of m6A modification in the regulation of BMSCs differentiating into adipocytes, which may pave a way to develop more effective therapeutic strategies in stem cell regenerative medicine and the treatment of obesity.-Yao, Y., Bi, Z., Wu, R., Zhao, Y., Liu, Y., Liu, Q., Wang, Y., Wang, X. METTL3 inhibits BMSC adipogenic differentiation by targeting the JAK1/STAT5/C/EBPβ pathway via an m6A-YTHDF2-dependent manner.

N6 -methyladenosine (m6 A), as the most abundant RNA epigenetic modifications, has been shown to play critical roles in various biological functions. Research about enzymes that can catalyze and remove m6 A have revealed its comprehensive roles in messenger RNA (mRNA) metabolism and other physiological processes. The "readers" including YTH domain-containing proteins, hnRNPC, hnRNPG, hnRNPA2B1, IGF2BP1, IGF2BP2, and IGF2BP3, which can affect the fates of mRNA in an m6 A-dependent manner. In this review, we focus on recent advances in the research of the m6 A modifications, especially about the latest functions of its writers, erasers, readers in RNA metabolism, cancer, and lipid metabolism. In the end, we provide insights into the underlying molecular mechanisms of m6 A modifications.

An efficient and stable combined denitrification-partial nitrification-Anammox process with a dual recycling system was used to remove nitrogen from mature landfill leachate. After 155 d of operation, the NO3− as the PN-Anammox byproduct was almost treated with biodegradable organic carbon in raw wastewater in a pre-denitrification reactor by external recycling system. When raw landfill leachate with NH4+-N concentration of 1900 mg/L was treated, an integrated reactor with airlift recycling was combined with the PN and Anammox reactions to efficiently remove NH4+ from the inflow. The total nitrogen concentration of effluent stabilized at 20 mg/L and total nitrogen removal efficiency was 99%. The maximum NO2− production rate in the aerobic zone was 2.2 kg/(m3·d) and the maximum nitrogen removal rate in the anaerobic zone was 21.4 kg/(m3·d). The most common phyla among the nitrification and the Anammox functional bacteria were Nitrosomonas, Candidatus Kuenenia, and Candidatus Brocadia after landfill leachate treatment.

N6-methyladenosine (m6A) is the most prevalent internal mRNA modification in eukaryotes. Loss of m6A demethylase FTO increases m6A levels and inhibits adipogenesis of preadipocytes. However, its underlying mechanism remains elusive. Here, we demonstrated that silencing FTO inhibited adipogenesis of preadipocytes through impairing cell cycle progression at the early stage of adipogenesis. FTO knockdown markedly decreased the expression of CCNA2 and CDK2, crucial cell cycle regulators, leading to delayed entry of MDI-induced cells into G2 phase. Furthermore, the m6A levels of CCNA2 and CDK2 mRNA were significantly upregulated following FTO knockdown. m6A-binding protein YTHDF2 recognized and decayed methylated mRNAs of CCNA2 and CDK2, leading to decreased protein expression, thereby prolonging cell cycle progression and suppressing adipogenesis. Our work unravels that FTO regulates adipogenesis by controlling cell cycle progression in an m6A-YTHDF2 dependent manner, which provides insights into critical roles of m6A methylation in adipogenesis.

Recovery of phosphorus (P) from wastewater is of great significance for alleviating the shortage of P resources. At present, the P recovery process is faced with the problem of excessive organic carbon consumption when obtaining a P-concentrated recovery solution. This study proposed a new strategy to obtain a more highly concentrated P recovery solution with minimal carbon consumption by strengthening the P storage capacity of the biofilm. A biofilm sequencing batch reactor (BSBR) process was modified to treat synthetic wastewater. The effect of the dissolved oxygen (DO) concentration on the P storage capacity of the biofilm was investigated at DO concentrations of DO 3.5 mg/L (PL) and DO 6.5 mg/L (PH). The results showed a maximum P storage of 101.2 and 149.6 mg-P/g-mixed liquid suspended solids under the two conditions. Strengthening the P storage capacity of the biofilm resulted in a net increase in the P recovery rate, which was as high as 66.96% in a harvesting cycle, and total soluble P>220 mg/L in the P recovery solution was successfully achieved. Meanwhile, the carbon cost of P recovery in the BSBR was reduced to 41.57 g-chemical oxygen demand/g-P, and the carbon utilization efficiency was enhanced. To highlight the new strategy, the P recovery performance of the BSBR was given and the relationship between P content and anaerobic P release was discussed. In addition, the changes in the microbial communities under PL and PH conditions were analyzed.

The constituent particles of matter can arrange themselves in various ways, giving rise to emergent phenomena that can be surprisingly rich and often cannot be understood by studying only the individual constituents. Discovering and understanding the emergence of such phenomena in quantum materials-especially those in which multiple degrees of freedom or energy scales are delicately balanced-is of fundamental interest to condensed-matter research1,2. Here we report on the surprising observation of emergent ferroelectricity in graphene-based moire heterostructures. Ferroelectric materials show electrically switchable electric dipoles, which are usually formed by spatial separation between the average centres of positive and negative charge within the unit cell. On this basis, it is difficult to imagine graphene-a material composed of only carbon atoms-exhibiting ferroelectricity3. However, in this work we realize switchable ferroelectricity in Bernal-stacked bilayer graphene sandwiched between two hexagonal boron nitride layers. By introducing a moire superlattice potential (via aligning bilayer graphene with the top and/or bottom boron nitride crystals), we observe prominent and robust hysteretic behaviour of the graphene resistance with an externally applied out-of-plane displacement field. Our systematic transport measurements reveal a rich and striking response as a function of displacement field and electron filling, and beyond the framework of conventional ferroelectrics. We further directly probe the ferroelectric polarization through a non-local monolayer graphene sensor. Our results suggest an unconventional, odd-parity electronic ordering in the bilayer graphene/boron nitride moire system. This emergent moire ferroelectricity may enable ultrafast, programmable and atomically thin carbon-based memory devices.

For over two decades, sulfate reduction with ammonium oxidation (SRAO) had been reported from laboratory experiments. SRAO was considered an autotrophic process mediated by anammox bacteria, in which ammonium as electron donor was oxidized by the electron acceptor sulfate. This process had been attributed to observed transformations of nitrogenous and sulfurous compounds in natural environments. Results obtained differed largely for the conversion mole ratios (ammonium/sulfate), and even the intermediate and final products of sulfate reduction. Thus, the hypothesis of biological conversion pathways of ammonium and sulfate in anammox consortia is implausible. In this study, continuous reactor experiments (with working volume of 3.8L) and batch tests were conducted under normal anaerobic (0.2 ≤ DO > 0.5 mg/L) / strict anaerobic (DO > 0.2 mg/L) conditions with different biomass proportions to verify the SRAO phenomena and identify possible pathways behind substrate conversion. Key findings were that SRAO occurred only in cases of high amounts of inoculant biomass under normal anaerobic condition, while absent under strict anaerobic conditions for same anammox consortia. Mass balance and stoichiometry were checked based on experimental results and the thermodynamics proposed by previous studies were critically discussed. Thus anammox bacteria do not possess the ability to oxidize ammonium with sulfate as electron acceptor and the assumed SRAO could, in fact, be a combination of aerobic ammonium oxidation, anammox and heterotrophic sulfate reduction processes.

The feasibility of using Feammox coupled with nitrate-dependent Fe(II) oxidizing (NAFO) to cause the simultaneous conversion of NH4+ and NO3− was explored by inoculation with Feammox sludge and the use Fe cycling as catalyst. After 61 days operation, the simultaneous conversion of NO3− and NH4+ occurred with the presence of interconversion between Fe(III) and Fe(II). The conversion ratio of NH4+ to NO3− stabilized at 0.9–1. The results of isotopic tracing and microbial diversity analysis indicated that NH4+ was first oxidized to NO2− by Fe(III), then NO3− was reduced to NO2− and N2 by the Fe(II) produced in Feammox process, and finally, the NO2− produced in NAFO process underwent an Anammox process with the remaining NH4+ to yield N2. The results showed the simultaneous continuous conversion process of NO3− and NH4+ with limited Fe as a catalyst was a coupled process of Feammox, Anammox, and NAFO under the anaerobic conditions.

The phosphorus recovery efficiency in PAOs-biofilm system is so far limited to stimulating phosphorus release by adding concentrated organic carbon solution during the anaerobic stage. In present study, a PAOs-biofilm sequence batch reactor (BSBR) were operated to investigate whether increase of the phosphorus storage content via DO control can stimulate the release in the biofilm. During the operation of BSBR for 160 days, the phosphorus content in biofilm (Pbiofilm) was doubled via increasing dissolved oxygen (DO) from 4 to 6 mg/L. With the COD of 200 mg/L in the anaerobic phase, the phosphorus release was enhaced, resulting in an significant increase of phosphorus concentration from 94.85 to 179.5 mg/L in recirculated solution. Batch tests further clarified explicitly the increase of Pbiofilm stimulated a phosphorus release rate but this must be balanced since high Pbiofilm reduced the phosphorus removal capacity of the biofilm. With analysis of P31-NMR, Ortho-P and Poly-P were the main phosphorus species stored in biofilm. The microbial cell played a more important role than EPS in phosphorus storage. The dominant phylum in the master reactor was Proteobacteria with an abundance of 64.4%, in which the Rhodocyclaceae was the dominant PAOs with an abundance of 10.1%. The outcome of this study elucidated that increase of phosphorus storage via DO control which facilitated more efficient phosphorus release with much lower organic carbon source consumption during the enrichment of phosphorus. Meanwhile, we provided a new perspective for the recovery of phosphorus in future wastewater treatment plants.

The effects of salinity changes on nitrogen transformation efficiency and recoverability were studied by using a partial nitration (PN)- anaerobic ammonium oxidation (Anammox) integrated reactor. The changes of microbial community structure and population abundance during the increase and decrease of salinity were also analyzed by 16S rRNA gene high-throughput sequencing. The results showed that when the salinity was increased to 1.35%, the combined PN-Anammox process achieved the maximum stimulated and total nitrogen removal rate (TNRR) arrived at 1.1kg/(m3·d). When the salinity was higher than 1.35%, the activities of AOB and Anammox bacteria began to be inhibited. When the salinity reached 2.4%, the TNRR decreased to 60%. TNRR was fast restored, when salinity was reduced to 0.11%. The genes of AOB and Anammox bacteria indicated that the TNRR of the reactor was restored after salinity inhibition, but the functional microbial community structure and abundance had relatively large, irreversible changes.

The InGaN/GaN multi-quantum-wells (MQWs) solar cells employing the surficial GaN nanostructure as light traps were investigated. The performance of the InGaN/GaN MQWs solar cell with nano holes surface shows an obvious advantage over that with nano poles, much less than the planar one. From the measurements of EQE and photoluminescence spectra, the enhancement of photoelectric response contributes to the device performances. Because the effective light absorption is increased, the conversion efficiency significantly improves from 1.02% (planar surface) up to 2.235% (nano holes surface). Although the performance is still low, it is exactly an effective method to enhance the conversion efficiency via introducing nanostructures on the surface of the InGaN/GaN MQWs cells.

In this work, a novel nitrate (NO3−) reduction pathway by anaerobic ammonium oxidation (anammox) biomass was firstly discovered with the intracellular carbon sources as the only electron donors. And the possible reaction mechanism was deduced to be intracellular dissimilatory nitrate reduction to ammonium (DNRA) pathway according to the experimental results. In batch experiments, without any external electron donors, NO3−-N (about 50 mg/L) was reduced to N2 within 48 h, and a small amount of NO2−-N was detected (the maximum of 2 mg/L) with the anammox biomass concentration of 4400 mg/L. Acetylene (4.46 mmol/L) addition resulted in obvious NH4+ accumulation during NO3− degradation by anammox biomass, since acetylene mainly interfered in hydrazine (N2H4) generation from NH4+ and NO. Without HCO3− addition, the NO3−-N degradation rate was slower than that with HCO3− addition. Simultaneously, glycogen contents inside anammox biomass decreased to 133.22 ± 1.21 mg/g VSS and 129.79 ± 1.21 mg/g VSS with and without HCO3−, respectively, from 142.20 ± 0.61 mg/g VSS. In the long-term experiment, anammox biomass stably degraded NO3−-N without external electron donors addition, and the maximum removal efficiency of NO3−-N reached 55.4%. The above results indicated the anammox bacteria utilized the DNRA pathway to reduce NO3− to NO2− and further NH4+, then normal anammox metabolism would continue to convert the produced NO2− and NH4+ to N2. The intracellular stored carbon sources (e.g., glycogen) were supposed to be electron donors for NO3− degradation. This capability would enhance the viability and living space of anammox bacteria in different natural ecosystems, and make it plausible that complete nitrogen removal could be implemented only by the anammox process.

An InGaN/GaN solar cell including a dual multiple quantum wells (MQWs) structure is investigated. It shows an obvious advantage over the conventional InGaN/GaN cell, which only contains a single MQWs structure. Because the short current density ( ${J} _{\mathrm { {sc}}})$ increases, the 1 sun power conversion efficiency significantly improves from 0.62% (single MQWs cell) to 1.02% (dual MQWs cell). From the measurement of EQE and PL spectra, the enhancement of effective photoelectric response within the solar spectrum mainly contributes to the high device performance, due to the introduced upper MQWs of higher In content.

For municipal wastewater with low temperature and ammonium, conventional oxygen-limited have difficulty achieving long-term stable inhibition of nitrite oxidizing bacteria (NOB) and stable nitritation. So a partial nitrification-anaerobic ammonium oxidation integrated reactor with independent partitions was used to investigate the feasibility of adding an auto-recycling system to promote low exposure of nitrite in the aerobic zone and to inhibit the NOB activity. The results showed that nitrite produced in the aerobic zone could be timely transported to the anaerobic zone for Anammox utilization, and the nitrite nitrogen concentration was diluted to keep within 1 mg/L in the aerobic zone by the effluent recycling. NOB growth was inhibited by nitrite deficiency. The maximum nitrogen removal rate of the reactor was 0.29 kg/(m3·d), and the nitrate nitrogen production rate of NOB was controlled within 0.04 kg/(m3·d). Nitrosomonas and Candidatus Kuenenia were found as functional species of ammonia-oxidizing bacteria and Anammox bacteria, respectively.

A mathematic model was developed for describing the nitrogen and organic carbon removal via the simultaneous anaerobic ammonium oxidation (anammox) and heterotrophic denitrification (SAD) process. The model considered anammox bacteria, heterotrophic denitrifying bacteria, ammonium, nitrite, nitrate, and readily biodegradable carbon. The model parameters were calibrated by using the experimental data in the single batch reactors inoculated with anammox sludge of 190 mg-VSS/L and activated sludge of 110 or 220 mg-VSS/L for treating wastewater containing ammonium of 30 mg-N/L and nitrate of 40 mg-N/L. The rapid depletion of nitrate and acetate as the sole carbon source were observed in the reactor. Subsequently, the temporarily accumulated nitrite was removed with ammonium. The initial C/N ratio of 1.5–2.0 and the population ratio of heterotrophic denitrifying bacteria to anammox bacteria within 0.3–0.4 were suitable conditions for the batch SAD process. The sensitivity analysis of kinetic parameters revealed that the most influential parameters for the nitrogen and organic carbon removal were the half-saturation constants for nitrite of heterotrophic bacteria and anammox bacteria and the anoxic reduction factors of heterotrophic bacteria on the nitrate-reducing rate and the nitrite-reducing rate, which closely associated with nitrite accumulation in the SAD process.

In this study, ternary Cu2SnS3 (CTS) nanostructure materials with high crystallinity were successfully prepared via a facile solvothermal method, which was followed by high-temperature treatment. The morphology of the as-synthesized samples is uniform flower-like spheres, with these spheres consisting of hierarchical nanosheets and possessing network features. Sodium storage measurements demonstrate that the annealed CTS electrodes have high initial reversible capacity (447.7 mAh&middot, g&minus, 1 at a current density of 100 mA&middot, 1), good capacity retention (200.6 mAh&middot, 1 after 50 cycles at a current density of 100 mA&middot, 1) and considerable rate capability because of their high crystallinity and unique morphology. Such good performances indicate that the high crystallinity CTS is a promising anode material for sodium ion batteries.

AlGaN/AlN/GaN heterojunctions were irradiated by 3 MeV protons with different fluences. Hall and C-V measurements showed that the density and mobility of 2DEG for heterojunctions decreased after proton irradiation. The crystal quality and optical properties of AlGaN/GaN heterojunctions were characterized by the variations of the micro-Raman scattering spectra, XRD and photo luminescence (PL) spectra with proton fluence. It has been obtained that the strain and dislocation of GaN and AlGaN were not affected by the proton injected. The proton irradiation caused the increase of structural defects in HT-AlN buffer layer, which lead to the red shift of ${{\rm A}_1}$ (LO) mode. The higher tails of XRD rocking curve indicated the introduction of point defects by irradiation. The full-width at half-maximum (FWHM) of ${\rm E}_2^{\rm high}$ phonon mode broadened, which was consistent with change of FWHM of PL near-band-edge emission (BE). The spectra of yellow band normalized to the intensity of BE demonstrated a great increase of Ga vacancies related defects, which may be the main reason for the degradation of optical properties.

The differences in the physiological characteristics between AOB and ANAMMOX bacteria lead to suboptimal performance when used in a single reactor. In this study, aerobic and anaerobic zones with different survival environments were constructed in a single reactor to realize partitioned culture of AOB and ANAMMOX bacteria. An external air-lift reflux system was formed which used the exhaust from the aeration zone as power to return the effluent to the aeration zone. The reflux system effectively alleviated the large pH fluctuations and promoted NO2--N to rapidly use by ANAMMOX bacteria, effectively inhibiting the activity of NOB. After 95d of running, the nitrogen removal rate increased from the initial 0.21kg/(m3·d) to 3.1kg/(m3·d). FISH analyses further demonstrated that AOB and ANAMMOX bacteria acquired efficient enrichment in the corresponding zone. Thus, this type of integrative reactor may create the environments needed for the partial nitritation-ANAMMOX processing.

This study investigated the inhibitory effects of Cd, Ag, Hg and Pb on Anammox biomass by batch experiments. Inhibition effects and recovery performance were monitored in sequence over 24 h and 72 h experimental runs. The IC50 (the 50% inhibitory concentration of nitrogen removal rate) values were calculated as follows: 11.16 ± 0.42 mg/L for Cd; 11.52 ± 0.49 mg/L for Ag; 60.35 ± 2.47 mg/L for Hg. Pb caused only 7.19% decrease on nitrogen removal rate (NRR) even at a dose of 40 mg/L. Hence, the order of the inhibitory effect was determined as Cd > Ag > Hg > Pb. Furthermore, the crude enzyme (hydrazine dehydrogenase) activity and heme c concentration were also depressed under heavy metals exposure. Among four metals, Cd and Hg could exert sustained toxicity on Anammox biomass, but mal-effects of Ag and Pb could resume to a large extent after removing these two metals within 96 h.

A novel turn-off fluorescent probe based on coumarin and imidazole moiety for extremely acidic conditions was designed and developed. The probe with pKa=2.1 is able to respond to very low pH value (below 3.5) with high sensitivity relying on fluorescence quenching at 460 nm in fluorescence spectra or the ratios of absorbance maximum at 380 nm to that at 450 nm in UV-vis spectra. It can quantitatively detect pH value based on equilibrium equation, pH=pKa-log[(Ix-Ib)/(Ia-Ix)]. It had very short response time that was less than 1 min, good reversibility and nearly no interference from common metal ions. Moreover, using (1)H NMR analysis and theoretical calculation of molecular orbital, we verified that a two-step protonation process of two N atoms of the probe leaded to photoinduced electron transfer (PET), which was actually the mechanism of the fluorescence quenching phenomenon under strongly acidic conditions. Furthermore, the probe was also applied to imaging strong acidity in bacteria, E.coli and had good effect. This work illustrates that the new probe could be a practical and ideal pH indicator for strongly acidic conditions with good biological significance.

The effect of 3-MeV proton irradiation on InGaN/GaN multiple quantum wells (MQWs) solar cells was investigated. The irradiation degradation of the photoluminescence characteristics of the InGaN film was also measured, indicating its potential to be used in space solar cells. With the proton fluence increasing from 0 to 1 × 10 14 /cm 2 , the conversion efficiency (η) of the InGaN/GaN MQWs cell declined from 0.61% to 0.14%.

Four shapes of Cu2O particles as sphere, cube, truncated octahedron and octahedron were prepared via glucose reduction of Cu(II) under alkaline condition. The products were characterized by XRD and SEM. The effects of the precursor (CuO, Cu(OH)2), reaction temperature and glucose concentration on morphology of Cu2O particles were investigated, and the mechanism of morphology control was discussed on the basic theory of crystal nucleation and growth. It is found that the Cu+ supersaturation is remarkably influenced by the precursor kind, reaction temperature and glucose concentration, and the morphology of Cu2O particles can be controlled by the Cu+ supersaturation.

Nitrogen-doped ZnO (ZnO:N) thin films with multi-buffer-layers, Mg0.1Zn0.9O / ZnO super-lattice structure, were grown on sapphire (0 0 0 1) by plasma-activated laser molecular beam epitaxy (L-MBE) using an atomic nitrogen source. High resolution X-ray diffraction (HR-XRD) measurement demonstrated that all the ZnO:N samples are (0 0 0 2) oriented and the residual strain along c-axial are effectively controlled. Room temperature (RT) Hall measurements indicate that the 200 °C sample shows a p-type behavior with a mobility of 4.08 cm2/V s and a carrier density of 1.47 × 1 0 17 cm−3. The 300 °C sample shows a weak p-type behavior with a mobility of 0.75 cm2/V s and a carrier density of 4.40 × 1 0 16 cm−3. However, the 200 °C sample is not stable and reverted back to n-type conductivity in about 5 days. The X-ray photoelectron spectra (XPS) of N1s display two peaks at 404 eV and 396 eV which are related to (N2)Oand NO, respectively. The 10 K low temperature photoluminescence (PL) spectra of the 200 °C sample exhibits an acceptor bound exciton peak at 3.351 eV and a donor–acceptor pair (DAP) peak at 3.228 eV, associated with NO acting as acceptors.

Adopted the distribution feedback type (DFB) laser to measure the coal mine gas methane, according to the methane located 1.6 μm nearby 2ν 3 with a R9 direct absorption spectrum, attraction wire intensity of each line was calculated through the multi-line Voigt fitting. The experimental result indicates that in the obtained four attraction recover of wire, the maximum deviation is 2.7%, and the minimum deviation is 0.02%, other results are all in experimental error scope. This research method may apply in the spectrum survey methane gas density, it has characteristics including high precision, strong selectivity, fast response and so on.

The thin film transistors (TFTs) based on nitrogen doped zinc oxide (ZnO) were investigated by laser molecular beam epitaxy. The increase of ZnO films' resistivity by nitrogen doping was found and applied in enhancement mode ZnO-TFTs. The ZnO-TFTs with a conventional bottom-gate structure were fabricated on thermally oxidized p-type silicon substrate. Electrical measurement has revealed that the devices operate as an n-channel enhancement mode and exhibit an on/off ratio of 10(4). The threshold voltage is 5.15 V. The channel mobility on the order of 2.66 cm(2) V-1 s(-1) has been determined. (c) 2007 Elsevier B.V. All rights reserved.

Plasma membrane intrinsic proteins (PIPs) are one subfamily of aquaporins that mediate the transmembrane transport of water. To reveal their function in poplar, we generated transgenic poplar plants in which the translation of PIP genes was downregulated by RNA interference investigated these plants with a comprehensive leaf plasma membrane proteome and physiome analysis. First, inhibition of PIP synthesis strongly altered the leaf plasma membrane protein composition. Strikingly, several signaling components and transporters involved in the regulation of stomatal movement were differentially regulated in transgenic poplars. Furthermore, hormonal crosstalk related to abscisic acid, auxin and brassinosteroids was altered, in addition to cell wall biosynthesis/cutinization, the organization of cellular structures and membrane trafficking. A physiological analysis confirmed the proteomic results. The leaves had wider opened stomata and higher net CO2 assimilation and transpiration rates as well as greater mesophyll conductance for CO2 (gm) and leaf hydraulic conductance (Kleaf). Based on these results, we conclude that PIP proteins not only play essential roles in whole leaf water and CO2 flux but have important roles in the regulation of stomatal movement. Biological significance The present work is a comprehensive survey combining leaf plasma membrane proteomics and physiological methods to assess the functionality of the whole PIP subfamily in tree model system.

In this study, three upflow column reactors were compared for anaerobic ammonium oxidation (Anammox) process start-up time with different ferrous iron concentration in feeding. Continuous experiments indicated that the start-up time of Anammox process could be shortened from 70 to 58d in R2 (0.06mM Fe(2+)) and 50d in R3 (0.09mM Fe(2+)). The Anammox activity appeared after 16days operation in R3. Quantitative PCR (q-PCR) analysis demonstrated a significant increase in quantity of Anammox bacteria in R3 compared with the other two reactors during entire operation. At the Fe(II) concentration of 0.09mM, the heme c levels inside Anammox cell and hydrazine dehydrogenase (HDH) activity increased dramatically, which could be the trigger of fast Anammox start-up.

In this study, we explored the effects of Fe(II) on the activity of anammox biomass both in short and long terms. With the influent Fe(II) at 0.09 and 0.12 mM, continuous experiments demonstrated that the nitrogen removal rates increased 32.2% and 29.9% compared to that with normal Fe(II) level (0.03 mM). Influent Fe(II) variation could affect the total Fe, heme c levels and hydrazine dehydrogenase activity. At the Fe(II) concentration of 0.09 mM, the total Fe, heme c levels inside anammox cell and hydrazine dehydrogenase activity could increase about 2.0, 2.1 and 2.35 folds as much as that with normal Fe(II) level. However, when the Fe(II) elevated to 0.18 mM, it would cause a mal-effect on anammox bacteria and further deteriorate nitrogen removal performance. It was indicated that the appropriate increase of Fe(II) was beneficial for more heme c synthesis, enhancement of hydrazine dehydrogenase activity, the growth of anammox bacteria.

This study examined long-term effect of MnO(2) powder (average diameter of 4-7 μm) on nitrogen removal in anammox process. Two lab-scale up-flow anammox reactors were operated for 380 days, one with and one without MnO(2) powder addition. During the period when only substrate concentrations varied, the maximum nitrogen removal rate in the reactor with MnO(2) addition reached 920.9 g-N/m(3)/d. This value was 2-folds higher than that (464.6 g-N/m(3)/d) of the reactor without MnO(2) addition. The crude enzyme activities of the anammox biomass from the two reactors was measured as 0.531±0.019 and 0.298±0.007 μmol cytochrome c reduced/mg protein/min, respectively. Transmission electron microscopy observation demonstrated more undefined particles existing inside anammox bacterial cell in the reactor with MnO(2) powder addition. Furthermore, filament-like structures inside anammoxosome were observed, which formed a net-like structure with particles as the connecting nodes. The experiment results demonstrated that MnO(2) improved nitrogen removal performance of anammox process.

Differential optical absorption spectroscopy (DOAS) has become a widely used method to measure trace gases in the atmosphere.Their concentrations can be retrieved by a numerical analysis of the atmospheric absorption spectra. But it has been found that DOAS could not gain continuous data under a bad weather condition.Thus it could not fully fit for the demand of the environment monitoring statute.A prediction technology has been developed, based on the stepwise regression analysis method.It is shown that the forecasting data using this method is consistent with the real data after doing a great deal of experiments. This technology has been used in practice.

The principle of differential optical absorption spectroscopy (DOAS) for measuring the concentration of air pollutants is presented. The adjustment of measured spectra and the least-squares method are also described .We have been using this method in retrieving the concentration of air pollutants and measuring the air pollutants for a long time and the results were coincident with circumstances. This method was proved very suitable for retrieving the concentration of air pollutants in DOAS system and provides a good technique for environmental monitoring.