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In this paper we propose new Z-type nonlinear weights of the fifth-order weighted essentially non-oscillatory (WENO) finite difference scheme for hyperbolic conservation laws. Instead of employing the classical smoothness indicators for the nonlinear weights, we take the p th root of the smoothness indicators and follow the form of Z-type nonlinear weights, leading to fifth order accuracy in smooth regions, even at the critical points, and sharper approximations around the discontinuities. We also prove that the proposed nonlinear weights converge to the linear weights as p → ∞ , implying the convergence of the resulting WENO numerical flux to the finite difference numerical flux. Numerical examples are presented by comparing with other WENO schemes, such as WENO-JS, WENO-M and WENO-Z, to demonstrate that the proposed WENO scheme performs better in shock capturing. [ABSTRACT FROM AUTHOR]

[Display omitted] • The addition of SFe could improve the denitrification ability. • The addition of SFe enhanced around 43 % TN removal efficiency than ordinary system. • SFe-sludge system improved NH 4 +-N degradation and reduced NO 3 −-N accumulation. • SFe enhanced 20 % activity of NAR. • The SFe-sludge system enriched autotrophic/aerobic denitrification bacteria. Sponge iron (SFe) coupled with a sludge system has great potential for improving biological denitrification; however, the underlying mechanism is not yet fully understood. In this study, the denitrification performance and microbial characteristics of ordinary sludge and SFe-sludge systems were investigated. Overall, the SFe-sludge reactor had faster ammonium degradation rate (94.0 %) and less nitrate accumulation (1.5–53.3 times lower) than ordinary reactor during the complete operation cycle of sequencing batch reactors. The addition of SFe increased the activities of nitrate and nitrite reductases. The total relative abundance of autotrophic denitrifying bacteria (Acidovorax , Arenimonas , etc.) in the SFe-sludge system after 38 days of operation was found to be 10.6 % higher than that in the ordinary sludge reactor. The aerobic denitrifying bacteria (Dokdonella , Phaeodactylibacter , etc.) was 5.3 % higher than ordinary sludge. The SFe-sludge system improved denitrification by enriching autotrophic/aerobic denitrifying bacteria in low carbon-to-nitrogen ratio wastewater treatment. [ABSTRACT FROM AUTHOR]

Fractional differential equations have become an important modeling technique in describing various natural phenomena. A variety of numerical methods for solving fractional differential equations has been developed over the last decades. Among them, finite difference methods are most popular owing to relative easiness for implementation. In this paper, we show that the finite difference method with the Riemann-Liouville (RL) fractional derivative yields inconsistent and oscillatory numerical solutions to fractional differential equations of discontinuous problems for the fractional order α , 0 < α < 1. Such an inconsistency affects even smooth problems since the numerical solution can be regarded as a discontinuous function over grids. We show that the inconsistency inherited in discontinuous problems causes the numerical solution for smooth problems to be oscillatory under certain conditions although the magnitude of the oscillations decreases as the number of grids, N , increases. That is, although the truncation error is decaying as N → ∞ and the method is consistent for smooth problems, the numerical solution can be oscillatory for any value of N. To illustrate the inconsistency and the oscillation phenomenon with the RL method, we also consider the finite difference methods with the Caputo and Grünwald-Letnikov fractional derivatives and compare the results with by with the RL method. We also show that the integral approach for the RL method can resolve the issues of the inconsistency and the oscillation phenomenon. Numerical results are presented to support the statements. [ABSTRACT FROM AUTHOR]

Background: Preeclampsia (PE) is a frequently occurring pregnancy disorder in the placenta, which results in various maternal and fetal complications. The current study aims to evaluate the role of extracellular vesicles (EVs)-encapsulated microRNA (miR)-101 in biological processes of trophoblasts in PE and its underlying mechanism. Methods: Human umbilical cord mesenchymal stem cell (HUCMSC) and HUCMSC-derived EVs were isolated and cultured, after which EV characterization was carried out using PKH67 staining. In silico analyses were adopted to predict the downstream target genes of miR-101, and dual luciferase reporter gene assay was applied to validate the binding affinity. Furthermore, loss- and gain-of-function approaches were adopted to determine the role of miR-101 and bromodomain-containing protein 4 (BRD4) in trophoblast proliferation and invasion using EDU staining and transwell assay. In addition, a rat model of PE was established to verify the function of EV-encapsulated miR-101 in vivo. Results: Placental tissues obtained from PE patients presented with downregulated miR-101 expression and upregulated BRD4 and CXCL11 expression. EV-encapsulated miR-101 from HUCMSCs could be delivered into the trophoblast HTR-8/SVneo cells, thus enhancing proliferation and migration of trophoblasts. Mechanically, miR-101 targeted and negatively regulated BRD4 expression. BRD4 knockdown promoted the proliferation and migration of trophoblasts by suppressing NF-κB/CXCL11 axis. EV-encapsulated miR-101 from HUCMSCs also reduced blood pressure and 24 h urine protein in vivo, thereby ameliorating PE. Conclusion: In summary, EV-encapsulated miR-101 promoted proliferation and migration of placental trophoblasts through the inhibition of BRD4 expression via NF-κB/CXCL11 inactivation. [ABSTRACT FROM AUTHOR]

Estimating failure probabilities of engineering systems is an important problem in many engineering fields. In this work we consider such problems where the failure probability is extremely small (e.g. ≤ 10 − 10 ). In this case, standard Monte Carlo methods are not feasible due to the extraordinarily large number of samples required. To address these problems, we propose an algorithm that combines the main ideas of two very powerful failure probability estimation approaches: the subset simulation (SS) and the multicanonical Monte Carlo (MMC) methods. Unlike the standard MMC which samples in the entire domain of the input parameter in each iteration, the proposed subset MMC algorithm adaptively performs MMC simulations in a subset of the state space, which improves the sampling efficiency. With numerical examples we demonstrate that the proposed method is significantly more efficient than both of the SS and the MMC methods. Moreover, like the standard MMC, the proposed algorithm can reconstruct the complete distribution function of the parameter of interest and thus can provide more information than just the failure probabilities of the systems. [ABSTRACT FROM AUTHOR]

Abstract: There are wide ranges of lutein and β-carotene in Chinese kale. This work assessed the capability of near-infrared reflectance spectroscopy (NIRS) to predict the contents of lutein and β-carotene in Chinese kale against HPLC analysis. Compared to other regression methods, the regression of modified partial least squares with math treatments of 2,4,4,1 (where the first number of 2 represents the second derivative of log1/R, the second of 4 is the gap in data points over which the derivative is calculated, the third and fourth numbers refer to the number of data points used in the first and second smoothing, respectively) showed the best results. The calibration equations of lutein and β-carotene were characterized by the coefficients of determination (RSQ) of 0.983 and 0.982 and standard error of 0.056 and 0.131mgg−1 DW, respectively. In cross-validation, high 1 minus variance ratio (1−VR) of 0.955 and 0.966 and standard error of 0.092 and 0.179mgg−1 DW for lutein and β-carotene were obtained, respectively. In external validations, the RSQ were 0.926 and 0.875 with standard error of 0.131 and 0.367mgg−1 DW, respectively. These results showed that NIRS could be used for the determination of carotenoids in Chinese kale. [Copyright &y& Elsevier]

Simultaneous nitrification and denitrification (SND) is a promising denitrification method. But so far, there have been few reports on the SND and denitrification mechanism of the coupled system with sponge iron (SI). In this paper, the denitrification performance of the mono-sludge system (only activated sludge), mono-carrier system (activated sludge + polyurethane foam) and coupled system (activated sludge + polyurethane foam and SI) was investigated. The study found that compared with the mono-sludge system, the TN removal efficiencies of the mono-carrier system and coupled system increased by 24% and 29.2%, respectively. The change of dissolved oxygen in the carrier of the coupled system showed that the time of forming anoxic and anaerobic micro-environment in one cycle decreased continuously until it reached zero. The nitrate-dependent ferric oxidizing bacteria Acidovorax and Aquabacterium appeared in the coupled system. In addition, it was found that the intervention of SI significantly increased the activity of membrane nitrate reductase (NAR). This study provides practical and useful technology for the treatment of domestic sewage. [Display omitted] • The average effluent TN concentration of the coupled system was 9.66 mg/L. • The biological SI system could realize SND. • SI could enhance the activity of denitrifying enzyme NAR. • Many iron-related denitrification bacteria appeared in the coupled system. [ABSTRACT FROM AUTHOR]

The Poisson type inequalities, which were improved by Shu, Chen, and Vargas-De-Teón (J. Inequal. Appl. 2017:114, 2017), are generalized by using Poisson identities involving modified Poisson kernel functions with respect to a cone. New generalizations of improved Poisson-Sch type inequalities are obtained by using the generalized Montgomery identity associated with the Schrödinger operator. As applications in quantum calculus, we estimate the size of weighted Schrödingerean harmonic Bergman functions in the upper half space. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nitrogen was efficiently removed by bio-chemical reactions. • The anaerobic-anoxic-aerobic microenvironment formed in BSIS. • Denitrification bacteria enriched along with iron bacteria in BSIS. • SI improved the denitrification ability and reactor stability. • 90 g/L SI addition obviously improved the nitrogen removal rate of BSIS. The application of sponge iron (SI) carriers can improve the biochemical treatment performance of sequencing batch reactors (SBR) during wastewater treatment. This study used SBR reactors to explore the effects of SI dosage on the nitrogen removal performance and reactor stability and microbial community structure under low temperature and ultra-low load. In contrast to conventional SBR, the average removal rate of total nitrogen (TN) in the biological sponge iron system (BSIS) was increased by 5.38 % for 45 g/L, 18.93 % for 90 g/L, and 13.52 % for 135 g/L, respectively. The nitrogen removal performance and reactor stability showed the best performance under the SI dosage of 90 g/L. The addition of SI formed the anaerobic-anoxic-aerobic microenvironments, which facilitate the propagation of denitrifying bacteria (Saccharimonadales , Hydrogenophaga) and iron bacteria (Rhodoferax and Acinetobacter) in the BSIS. This study provides a new insight on the application of SI in the wastewater treatment. [ABSTRACT FROM AUTHOR]

The optical polarization properties of AlGaN/AlN conventional rectangular shaped and triangular shaped quantum wells (QWs) were investigated using the modified theoretical model based on the effective mass equation. The calculated results show that there is more emission component with TE polarization from triangular shaped QWs than that from conventional QWs for same peak emission wavelength, which is beneficial to the surface emission of Al-rich AlGaN-based light-emitting diodes (LEDs). Furthermore, the AlGaN/AlN triangular shaped QWs have shorter critical wavelength for polarization switching between dominant TE and TM emissions than conventional QWs. This is because that valence subband structure changes for the special band edge potential in AlGaN/AlN triangular shaped QWs. So, the polarization control to enhance the surface emission of DUV AlGaN-based LEDs can be realized by using triangular shaped QWs structure. [ABSTRACT FROM AUTHOR]

In this study, two compounds of triethylene glycol bistosylate (C20H26O8S2, I) and 1,8-bis(4-nitrophenoxy)-3,6-dioxaoctane (C18H20N2O8, II) were synthesized. Their structures were characterized by 1H NMR, 13C NMR, FT-IR, melting-point and elemental analysis, as well as X-ray single-crystal diffraction. The analyses of X-ray single crystal diffraction showed that the monomer of compound I was in sigmoid conformation due to the intramolecular C-H···π interaction, furthermore, a 3D network structure was constructed by five C-H···O hydrogen bonds. Unlike the compound I, the compound II was linked by two C-H···O hydrogen bonds through nitro and aromatic rings to form a 2D network structure. Host-guest chemistry of compounds II and β-cyclodextrin was also investigated by 1H NMR, FT-IR and UV-Vis spectra. The binding ratio of the compound II and β-cyclodextrin was 1:2 and the association constant Ka was 5.31 × 104 L2·mol−2 obtained by UV-Vis spectra. The X-ray single-crystal structural characterization suggests that the compound I was in sigmoid conformation due to the intramolecular C-H···π interaction, furthermore, a 3D network structure was constructed by five C-H···O hydrogen bonds formed between the monomers through SO3 groups and the hydrogen atoms on the surrounding three monomers glycol. The compound II was linked by two C-H···O hydrogen bonds through nitro and aromatic rings to form a 2D network structure. The two triethylene glycol derivatives (compound I, compound II) have been synthesized and characterized by 1H NMR, IR, melting point, elemental analysis and X-ray single crystal diffraction. The single crystals of compound I and compound II were cultured, and their intermolecular solid-state structures and weak interactions were obtained by X-ray single crystal diffraction. The compound I was in special sigmoid conformation due to the intramolecular C-H···π interaction and a 3D network structure was constructed by five intermolecular C-H···O hydrogen bonds. The compound II was linked by two C-H···O hydrogen bonds through nitro and aromatic rings to form a 2D network structure. The H-bonding interactions in the compound I and compound II were studied. The host-guest chemistry between compound II and β-cyclodextrin was investigated including the apparent stoichiometry ratio and the association constant (Ka) between them. [ABSTRACT FROM AUTHOR]

Background: Maternal subclinical hypothyroidism (SCH) has been associated with adverse pregnancy outcomes. This study aimed to explore whether SCH in the first trimester contributed to the development of gestational diabetes mellitus (GDM). Materials and Methods: A total of 8,777 pregnant women who first visited before 13 weeks and 6 days of gestation and accepted routine prenatal service at the Third Affiliated Hospital of Sun Yat-Sen University from January 2015 to September 2018 were recruited in this study. Thyroid functions (thyroid stimulating hormone [TSH], free T4, and thyroid peroxidase antibody [TPOAb]) were measured before 13 weeks and 6 days of gestation and data of 7,536 subjects with TSH ≥0.1 mIU/L were analyzed. A 2-hour 75-g oral glucose tolerance test was performed between 24 and 28 gestational weeks. Chi-square test and multivariate logistic regression analysis were applied to evaluate the relationship between SCH and GDM. Results: The prevalence of SCH in this population was 7.53%. After stratifying the relationship between SCH and GDM according to TSH concentrations (slightly elevated TSH: ≥2.5, <4.0 mIU/L; moderately elevated TSH: ≥4.0, <10.0 mIU/L) and TPOAb status, a moderately elevated TSH combined with positive TPOAb (23.9% vs. normal 13.0%, chi-square = 6.317, p = 0.012) was found to increase the incidence of GDM. Furthermore, after adjusting for confounders (maternal age, educational levels, parity, and pregestational body mass index [preBMI]), the SCH group still exhibited a higher risk of GDM (relative risk [RR] 1.867, 95% confidence interval [CI] 1.018–3.424). Conclusion: Our findings indicated that SCH during early pregnancy, in the presence of moderately elevated TSH levels and positive TPOAb, might lead to an increased risk of GDM. [ABSTRACT FROM AUTHOR]

Carbon dots (CDs) synthesized from natural products received considerable attention due to their unique properties. In this work, CDs were synthesized using Luochuan Red Fuji apple peels as carbon source (Ap-CDs) by direct hydrothermal reaction, and were characterized by Transmission Electron Microscope (TEM), X-ray Diffraction (XRD), Raman spectra, Fourier-transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Ultraviolet and visible (UV-Vis) absorption spectra and Fluorescence (FL) spectroscopy. The effect of reaction temperature, reaction time and the amount of carbon source used on the fluorescent intensity of Ap-CDs was studied. Fluorescent properties measurement indicated that when irradiated by ultraviolet at the wavelength of 350 nm, the Ap-CDs give out bright blue emitting at the maximum wavelength of 433 nm with quantum yield of 9.43%. Meanwhile, it was found that the fluorescent intensity of Ap-CDs could be selectively quenched by Fe 3 + ions. The fluorescent quenching of Ap-CDs was linearly related to the concentration of Fe 3 + ion in the range of 0.05–300 μ M with the detection limit of 1.56 μ M. Accordingly, the concentration of Fe 3 + ion in the tap water and pork liver samples were tried to be measured by the fluorescent quenching Ap-CDs. Carbon dots (CDs) synthesized from natural products had received considerable attention due to their unique properties. In this work, CDs were synthesized using Luochuan Red Fuji apple peels as carbon source (Ap-CDs) by direct hydrothermal reaction and were characterized by Transmission Electron Microscope (TEM), X-ray Diffraction (XRD), Raman spectra, Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), Ultraviolet and visible absorption spectra (UV-Vis) and Fluorescence spectroscopy. The effect of reaction temperature, reaction time and the amount of carbon source used on the fluorescent intensity of Ap-CDs were studied. Fluorescent properties measurement indicated that when irradiated by ultraviolet at the wavelength of 350 nm, the Ap-CDs give out bright blue emitting at the maximum wavelength of 433 nm with quantum yield of 9.43%. Meanwhile, it was found that the fluorescent intensity of Ap-CDs could be selectively quenched by Fe3+ ions. The fluorescent quenching of Ap-CDs was linearly related to the concentration of Fe3+ ion in the range of 0.05-300 μM with the detection limit of 1.56 μM. Accordingly, the concentration of Fe3+ ion in the tap water and pork liver samples were tried to be measured by the fluorescent quenching Ap-CDs. [ABSTRACT FROM AUTHOR]

This study mainly combines single factor experiment with orthogonal experiment to systematically investigate the effects of particle size, inoculum amount, pH value of the medium, ultrasonication time and species of surfactant on biodesulfurization of the high sulfur coal from Shanxi by using Thiobacillus ferrooxidans, Escherichia coli and Pseudomonas putida. The results revealed that the dominant strain was Pseudomonas putida which attained 58.23% of total sulfur removal during 10 days at the particle size of -125 + 75 μm, pH of 6.0, inoculum amount of 25 mL, ultrasonication time of 60 mins and Tween 80 concentration of 0.1%. Analysis of raw coal and biotreated coal by FTIR spectroscopy and X-ray diffraction indicated a modification of the coal structure after biodesulfurization. The curves of thermogravimetry (TG) for raw coal and biotreated coal also showed that the temperature of the coal pyrolysis significantly reduced, which meant that the thermal stability of the coal after biodesulfurization was lowered than raw coal. And the energy value of coal was not affected in the biodesulfurization process. After treatment with Pseudomonas putida, its calorific value only increased from 6308 cal/g to 6326 cal/g. Liquid products after biodesulfurization were extracted with a series of organic solvents, and each extract was characterized by gas chromatography-mass spectrometry (GC/MS), indicating the presence of sulfur-containing organic compounds in the liquid phase product. Ultimately, following these characterization results, the desulfurization mechanisms of all three bacteria were derived. [ABSTRACT FROM AUTHOR]

A copper(II) acetate complex with a urea‐functionalized pyridyl ligand, [CuL(OAc)2]2·2AcOH (1) [L = N‐(3‐chlorophenyl)‐N'‐(3‐pyridyl) urea], was synthesized by the reaction of L with Cu(OAc)2 in methanol. A zigzag‐shaped hydrogen bond chain of L is obtained via urea N–H···Npyridyl interactions, and a two‐dimensional hydrogen bond network structure is further formed through the C–H···O interaction. In the complex 1, a paddle‐wheel structure is generated by Cu···Oacetate interactions and Cu···Npyridyl interactions. Furthermore, hydrogen bonding chain structure is extended through weak C–H···O hydrogen bond interactions. Through ultraviolet‐visible (UV/Vis) spectroscopy, the acetate binding properties of L in solution were also evaluated. Variable temperature magnetic susceptibility measurement indicates that the metal complex 1 displays antiferromagnetic coupling property. [ABSTRACT FROM AUTHOR]

Twelve-coordinated sulfate hydrogen bonding interactions in water-containing Fe(II) system, [Fe0.5(H2O)3]2SO4·H2O (1), are reported herein. The X-ray single-crystal structural characterization suggests that the SO42− anion is coordinated by a total of twelve O–H···O hydrogen bonds from coordinated or free water molecules, with each sulfate O atom accepting three H-bonds in water-containing Fe(II) system. A well-defined cyclic (10) H-bonding motif is found in the sulfate − water clusters, which is extended into 2D sulfate − water H-bonding sheet. An 1D infinite [SO42−−H2O]n chain is further cross-linked with the 2D H-bonding sheet above mentioned to form a 3D sulfate − water hydrogen bonding network stabilized by the O–H···O hydrogen bonds interactions. The sulfate saturated coordination of 12 hydrogen bonds from water molecules in its first hydration shell is confirmed by X-ray crystallography. [ABSTRACT FROM AUTHOR]

The uniformity of flow field inner the reactor plays a crucial role for hydride vapor phase epitaxy (HVPE) crystal growth and its more important for large scale substrate. A new nozzle structure was designed by adding a push and dilution (PD) gas pipe in the center of gas channels for a 4-inch HVPE (PD-HVPE) system. Experimental results showed that the thickness inhomogeneity of 46 μm 4-inch GaN layer could reach ±1.8% by optimizing PD gas, greatly improved from ±14% grown with conventional nozzle. The simulations of the internal flow field were consistent with our experiment, and the enhancement in uniformity should be attributed to the redistribution of GaCl and NH 3 upon the wafer induced by PD pipe. The full width at half maximum (FWHM) of X-ray diffraction rocking curves for the 4-inch GaN film were about 224 and 200 arcsec for (002) and (102) reflection. The dislocation density of as-grown GaN was about 6.4×10 7 cm −2 . [ABSTRACT FROM AUTHOR]

Background: The association between isolated maternal hypothyroxinemia (IMH) and adverse pregnancy outcomes is still controversial. This study aimed to evaluate the association between IMH during the first trimester and adverse pregnancy outcomes in southern Chinese women.Methods: This was a hospital-based, retrospective cohort study. The records of 7051 women, including 1337 IMH women and 5714 euthyroid women who had a singleton pregnancy and accepted routine prenatal service at the Third Affiliated Hospital of Sun Yat-Sen University from January 2015 to September 2018, were extracted from the electronic medical records system in this study. Thyroid functions [thyroid-stimulating hormone (TSH), free thyroxine (fT4) and anti-thyroperoxidase autoantibody (TPO-Ab)] had to be measured before 13 weeks and 6 days of gestation. The chi-square test and multivariate logistic regression analysis were applied to evaluate the association between IMH during the first trimester and adverse pregnancy outcomes.Results: Prepregnancy obesity [prepregnancy body mass index (preBMI) ≥ 25 kg/m2] was found to be more common in the IMH group (11.2% vs. 6.1%) (P < 0.05). The prevalence of gestational diabetes mellitus (GDM), postpartum haemorrhage (PPH), macrosomia and large for gestational age (LGA) was higher in the IMH group. However, after using multivariate logistic regression analysis to adjust for confounders (maternal age, educational levels and preBMI), only LGA was shown to be associated with an increased risk in IMH women [adjusted OR: 1.27 (95% CI 1.044-1.566)]. The prevalence of preterm delivery (either < 37 or < 34 weeks), gestational hypertension, preeclampsia, placenta previa, placental abruption, premature rupture of membrane (PROM), intrauterine growth restriction (IUGR), polyhydramnios, stillbirth, small for gestational age (SGA) and low Apgar score did not increase.Conclusion: IMH during the first trimester did not increase any risk of adverse pregnancy outcomes in southern Chinese women except LGA. [ABSTRACT FROM AUTHOR]

The application of anaerobic ammonium oxidation (Anammox) technology in low-strength wastewater treatment still faces difficult in-situ start-ups and unstable operations. Sponge-iron sludge (R1) was used as a novel inoculum to provide a promising solution. Conventional activated sludge (R0) was used as the control. However, little is known about the feasibility and performance during the start-up and operation of Anammox combined with biological iron and iron bacteria in an iron sludge system. Anammox was successfully started both in R1 (87 days) and R0 (89 days) with a low-strength influent (with a nitrogen loading rate (NLR) of 43.64 ± 0.41 g N/(m3⋅d)). During long-term operation, the R0 nevertheless produced higher nitrates (9.7 ± 0.1 mg/L) than expected. In contrast, R1 presented no excess nitrate production (2.1 ± 0.06 mg/L). The total inorganic nitrogen (TIN) removal efficiency increased from 78.2 ± 7.1% in R0 to 86.1 ± 4.3% in R1. The iron sludge in R1 was divided equally into three parts and three different nitrogen-feeding methods were used over the 34 days of operation, as follows: first using a mixture of ammonium (27.15 ± 1.0 mg/L) and nitrite (32.7 ± 1.7 mg/L), then only ammonium (27.15 ± 1.0 mg/L) and lastly only nitrite (32.7 ± 1.7 mg/L) as the influent. R1 was a coupled system composed of Anammox, Feammox, and NO x −-dependent Fe(II) oxidation (NDFO). The contribution of Feammox and NDFO to TIN removal was 27.1 ± 1.2% and 31.9 ± 0.7%. However, Anammox was the primary nitrogen transformation pathway. X-ray diffraction (XRD) analysis shows that iron hydroxide (Fe(OH) 3) and iron oxide hydroxide (FeOOH) were generated in R1. The produced Fe(OH) 3 and FeOOH were capable of participating in Feammox and formed a Fe(II)/Fe(III) cycle which further removed nitrogen. Therefore, a highly stable and impressive nitrogen removal performance was demonstrated in the iron sludge Anammox system under the cooperation of biological iron and iron bacteria. The study considered the enrichment of norank_c_ OM190 , Desulfuromonas , and Thiobacillus and their contribution to the Anammox, Feammox, and NDFO processes, respectively. This study provides a new perspective for the start-up and stable operation of low-strength wastewater Anammox engineering applications. [Display omitted] • The sponge-iron sludge system (R1) showed the efficient and stable removal of TIN. • Cooperation of iron and iron bacteria was key to ensure the success of R1. • R1 was a coupled system composed of Anammox, Feammox and NDFO. • Anammox was the primary nitrogen transformation pathway. [ABSTRACT FROM AUTHOR]

The impact of strain on optical polarization of c-plane Al 0.37 Ga 0.63 N/Al 0.5 Ga 0.5 N multiple quantum wells (QWs) has been studied by the polarized photoluminescence spectroscopy at room temperature. By adopting multiple alternation cycles of low- and high-temperature growth, the strain state of AlN template can be modulated. With increasing in-plane compressive strain of QWs layers, the polarization degree can be enhanced from 41.5% to 61.9%. Furthermore, the strain dependence of the polarization degree has been confirmed by the numerical simulation based on k·p method, revealing the dominant role of energy level shift and wavefunction overlap. It is found that the relative position of the three valence subbands is responsible for the steep increase of the polarization at smaller strain, while the wavefunction overlap induced by piezoelectric effect modulates the optical polarization at larger strain. These results are of great importance in the design and analysis of AlGaN based ultraviolet light emitting devices. • The influence of strain on optical polarization was studied in c-plane AlGaN QWs. • The strain state of AlN template was modulated, achieving the prominent enhancement of TE mode emission. • The numerical simulation based on k·p methodconfirms the dominant role of energy level shift and wavefunction overlap. [ABSTRACT FROM AUTHOR]