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Fe/Co metal–organic frameworks (Fe/Co-MOFs) were synthesized by a solvothermal method using terephthalic acid (BDC) and N,N-dimethylformamide (DMF), and the removal of tetracycline (TC) was accomplished with high efficiency. We explored the influence of Co content on the characteristics of the bimetallic MOFs. The structures of the Fe/Co-MOFs were characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and nitrogen physisorption analysis. The results showed that Co2+ was well loaded in the Fe-MOFs. Due to the different coordination behaviors of Co2+ and Fe3+ with BDC, the Fe/Co-MOFs formed a new 3D structure with a spike ball-like morphology. The morphology changed dramatically, leading to a large specific surface area, and the activity of the Lewis acid sites was greatly enhanced. Through FTIR and XPS analysis before and after adsorption, the adsorption process was mainly affected by coordination action. The largest TC adsorption capacity was observed when the Fe/Co ratio was equal to 1:3, and the saturated adsorption capacity was 139.8 mg g−1. [ABSTRACT FROM AUTHOR]

A resonant absorber enables low-temperature sintering of InZnO sol–gel films with low-energy-density intense pulse light (IPL) irradiation (1 J/pulse). A back-gate structure, incorporated with a resonant absorber, exhibits effective light absorption. A device fabricated based on such a gate structure and sintered with irradiation of 50 pulses (∼50 J/cm2) demonstrates good electrical properties with a mobility of 0.34 cm2/V s and an on–off ratio of 106 and a substrate temperature under 210 °C, showcasing that employing a resonant absorber could enable low-temperature sintering of sol–gel films with low-energy-density irradiation. Further x-ray photoelectron spectroscopy analysis of the oxygen and nitrogen peaks indicates that IPL irradiation facilitated sol–gel reactions in films. [ABSTRACT FROM AUTHOR]

Chemical wood modification has been used to modify wood and improve its decay resistance. However, the mode of protective action is still not fully understood. Occasionally, outdoor products made from chemically modified timber (CMT) show internal decay while their outer shell remains intact. Hence, it was hypothesized that wood decay fungi may grow through CMT without losing their capability to degrade non-modified wood. This study aimed at developing a laboratory test set-up to investigate (1) whether decay fungi grow through CMT and (2) retain their ability to degrade non-modified wood. Acetylated and 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) treated wood were used in decay tests with modified 'mantle specimens' and untreated 'core dowels'. It became evident that white rot (Trametes versicolor), brown rot (Coniophora puteana) and soft rot fungi can grow through CMT without losing their ability to degrade untreated wood. Consequently, full volume impregnation of wood with the modifying agent is required to achieve complete protection of wooden products. In decay tests with DMDHEU treated specimens, significant amounts of apparently non-fixated DMDHEU were translocated from modified mantle specimens to untreated wood cores. A diffusion-driven transport of nitrogen and DMDHEU seemed to be responsible for mass translocation during decay testing. [ABSTRACT FROM AUTHOR]

The composition analysis of the acrylonitrile butadiene styrene (ABS) copolymer was performed using a method combining elemental analysis and 1H nuclear magnetic resonance (NMR) spectroscopy. The physicochemical properties of ABS are determined by the relative contents of the constituent monomers. However, because ABS undergoes a complicated microstructural change during the polymerization process, it is difficult to accurately analyze the relative contents using only a typical method. In this study, a combination of nitrogen elemental analysis and 1H NMR spectroscopy was proposed as an analytical method that can consider the effects of changes in the microstructures. This approach confirmed whether the ABS samples were close to meeting the specifications. In addition, the composition analyses of polylactic acid/ABS blends, polycarbonate/ABS blends, and a polyamide 6/ABS mixture sample indicate that the obtained results were consistent with the expected values, thereby demonstrating that this combined analytical approach can be applied to various types of ABS copolymer systems. [ABSTRACT FROM AUTHOR]

We report the synthesis of a unique cubic metal–organic framework (MOF), Fe‐HHTP‐MOF, comprising hexahydroxytriphenylene (HHTP) supertetrahedral units and FeIII ions, arranged in a diamond topology. The MOF is synthesized under solvothermal conditions, yielding a highly crystalline, deep black powder, with crystallites of 300–500 nm size and tetrahedral morphology. Nitrogen sorption analysis indicates a highly porous material with a surface area exceeding 1400 m2 g−1. Furthermore, Fe‐HHTP‐MOF shows broadband absorption from 475 up to 1900 nm with excellent absorption capability of 98.5 % of the incoming light over the visible spectral region. Electrical conductivity measurements of pressed pellets reveal a high intrinsic electrical conductivity of up to 10−3 S cm−1. Quantum mechanical calculations predict Fe‐HHTP‐MOF to be an efficient electron conductor, exhibiting continuous charge‐carrier pathways throughout the structure. [ABSTRACT FROM AUTHOR]

The presented work follows the theme of applied chemistry toward nanomaterials and multiphase functional systems of practical importance. Structural studies of nanocomposite materials are important due to the correlation between physicochemical/structural properties and their application potential. In this work, we report the fabrication and structural characterization of nanocomposite materials constituting noble metal (plasmonic) nanoparticles (AgNP and AuNP) dispersed on selected types of nanostructured solid hosts (nonporous silica, microporous activated carbon, chitosan biopolymer, and ordered mesoporous silica). The ability to maintain a dispersed state of colloidal precursors throughout their deposition on solid hosts was assessed. The influence of the carrier role in the formation and stabilization of nanometallic phases was evaluated taking into account the physicochemical and textural properties of the support surfaces. The size and shape of nanoobjects, clustering effects, interfacial properties, and stability of the immobilized nanophase were implemented by analyzing relevant parameters of SAXS analysis. The dimensional characteristic of the scatterers was evaluated by volume-weighted particle size distribution Dv(R). The detailed overall shape and maximal particle dimension were described by the analysis of pair distance distribution functions (PDDFs). The radius of gyration (Rg) from PDDF and Guinier approximation was calculated for illustrating the dimension of scattered heterogeneities in the investigated solids. The asymptotic behavior of a scattering curve and Porod theory were applied for determining the diffusion and quality of the interfacial surfaces. The size and morphology of nanoparticles in colloidal precursor solutions have been defined as spherical and bimodal in size (~ 6 nm and 20 nm). It was observed that the spherical shape and dispersed state of nanoparticles were achieved for all systems after deposition. However, the morphology of their final form was conditioned by the solid matrices. The particle properties from SAXS were correlated with properties determined by TEM and low-temperature nitrogen sorption analysis. Obtained results suggest good compatibility and correctness of SAXS data reading of nanocomposite systems and can be successfully applied for quick, nondestructive, and effective evaluation of structural properties of complex systems. [ABSTRACT FROM AUTHOR]

The purpose of this research is that clearly comprehends the conversion and reaction mechanism of N radical in burning reaction. The harmonic and anharmonic rate constants of the related reactions were calculated by the transition state (TS) theory and Yao and Lin (YL) method. And the kinetic and thermodynamic parameters considering anharmonic and harmonic factor were fitted respectively. In conclusion, the anharmonic effect cannot be ignored on the reaction process of N radical conversion. Besides, the simulation by CHEMKIN will be carried out by the fitted results in the future work. Therefore, the calculation can provide theoretical basis for the further research of the N‐related reactions, such as on the aspect of the removal of NOx. [ABSTRACT FROM AUTHOR]

Nitrogen balance (NB) experiments allow calculation of N retention in the body by subtracting N excreted in feces (NF), urine (NU) and milk (NM) from N intake (NI). In a previous study, we found that NB data from experiments with lactating dairy cows were generally high and, in the current meta-analysis, we update our earlier study with experiments from the last 2 decades and investigate probable causes of error. A total of 83 publications, with 86 experiments and 307 dietary treatments, were selected from top-ranked scientific journals that reported all NB components. The NB and NB components were analyzed by linear regression with a model that used NI as an independent variable and experiment as a random effect. The NF, NU and NM each represented 27 to 34% of NI, and the remaining N accumulated in the body was equal to 38.5 g/d (overall SD = 43.2 g/d). Retained N (as g/d or % of NI) increased linearly with NI, and this led to unlikely high N retentions, especially at high NI. Both NF and NU (g/d) increased with increasing NI, and we assume that some N in feces and urine were unaccounted. Only ~22% of experiments measured N in wet feces samples and, when analysis used dry samples, no mention of corrections due to potential volatile N losses during drying were reported. No experimentalists preserved feces immediately to prevent volatilization during collection. Moreover, ~27% of experiments estimated urine volumes by concentration of creatinine in spot samples, and in these experiments, NU was ~12% lower than those where total urine was collected (168 vs. 191 g/d). Only 40 experiments reported the volume and concentration of acids used for urine preservation, 33 furnished incomplete information, and the remainder did not describe the urine preservation method. In conclusion, the results of NB experiments using lactating dairy cows overestimate N retention, and the losses of N from feces and urine are the most probable reason. [ABSTRACT FROM AUTHOR]

For the first time, a direct non‐local thermodynamic equilibrium (NLTE) analysis of carbon and nitrogen lines in the spectra of nine RR Lyrae stars was carried out. We have determined the abundances of these elements together with oxygen, and have shown that the nitrogen content is increased in metallicity‐deficient program stars. We conclude that this is a sign of the first dredge up, which occurred at the previous stage of the red giant branch, and brought material processed in an incomplete carbon, nitrogen, oxygen (CNO) cycle to the surface of the star. This effect is significantly enhanced by thermohaline (extra‐) mixing, which is more effective for metal‐poor RR Lyrae stars. This is clearly seen in the plot showing that C/N ration in our sample of stars gradually decreases as metallicity decreases from about −0.2 to −2. Oxygen abundance depends on metallicity in a similar way to what we see in the Population II stars. [ABSTRACT FROM AUTHOR]

The objective of this trial was to study the effect of subclinical zinc (Zn) deficiency in lambs on productive variables, nitrogen (N) balance and hematological parameters. Ten Corriedale lambs, with an average weight of 10.09 kg, were randomly assigned to two groups: Basal (B, 10 ppm Zn) and Supplemented with 30 ppm Zn (Z). The trial lasted 20 weeks. The animals were weighed every 4 weeks. Also with this periodicity, they were bled by jugular venipuncture. In weeks 6 and 20 the apparent dry matter digestibility (ADMD) and N balance were evaluated. At the end of the test the wool production and quality were measured. The weight gain and wool quality were similar in both groups, while wool production was 37.4% higher in group Z. According to the first balance period, ADMD was similar in both groups, but the retention of N was significantly higher in group Z than in group B (5.53 vs 4.03 g/day). In the second balance period there was a similar trend. There were no differencies between groups on hematocrit, hemoglobin concentration, red blood cells, total leukocytes, lymphocytes and neutrophils number. These results suggest that subclinical Zn deficiency reduces wool production, which may be related to lower protein synthesis. [ABSTRACT FROM AUTHOR]

In this work, the formation of clusters in a supersonic jet expansion has been investigated. Clusters of argon, carbon-dioxide, nitrogen, and oxygen have been generated in the gas jet with three different types of nozzles (0.5mm diameter, 0.8mm diameter, and a conical nozzle with 0.8mm diameter aperture). The mean size and density of the clusters have been measured as a function of backing pressure. Here, density of clusters refers to the density of the cluster collection. Rayleigh scattering experimental data and Mach-Zehnder interferometer data have been combined to estimate the average size and density of clusters. CO2 and Ar clusters form easily at about a backing pressure of 2 bars, while N2 and O2 clusters do not form easily. N2 and O2 begin to cluster at a backing pressure of about 18-24 bars. The mean cluster radius of Ar varies from 6.6Å to 24Å and the cluster radius of CO2 varies from about 8.8Å to 35Å as the backing pressure increases from 3 bars to 14 bars. In the same range of backing pressures, the average cluster gas density changes from 37.3×1015 cm-3 to 1.6×1015 cm-3 for Ar clusters and changes from 10.52×1015 cm-3 to 0.22×1015 cm-3 for CO2 clusters. It is assumed that the condensation into clusters is total. The mean cluster radius of N2 is smaller and varies approximately from 4.2Å to 8.6Å and the cluster radius of O2 varies from about 4.9Å to 12.4Å as the backing pressure increases in the range of 18 bars to 35 bars. In the same range of backing pressures, the average cluster density changes from 48.2×1016 cm-3 to 3.7×1016 cm-3 for N2 clusters and from 21.5×1016 cm-3 to 1.3×1016 cm-3 for O2 clusters. [ABSTRACT FROM AUTHOR]

The paper investigates the reason for the cracking and leaking of stainless-steel (SS) tanks used to store processed hot water in rice boiling and husking plants. A detailed analysis of tank specimen samples using radiography, optical metallography, scanning electron microscopy, EDAX reveals that stress corrosion cracking (SCC) is the prime reason for the failure. The presence of favorable microstructure, environment and stress promoted the nucleation and propagation of SCC in the tank weldment. The evolution of the microstructure in the selected stainless grade was studied and discussed using Scheffler–Delong diagram. The formation of martensite in low nickel, high nitrogen austenitic stainless steel was observed to significantly influence the mechanical properties and promote SCC. The decreased pitting corrosion resistance of the material compared to SS 316 alloy was an important factor in the initiation of pits which acted as nucleation sites for SCC. [ABSTRACT FROM AUTHOR]

Porous silicon layers with different porosities were prepared by adjusting the anodization current density of the electrochemical etching process, starting from highly doped p‐type crystalline silicon wafers. The microstructural parameters of the porous layers were assessed by high‐resolution X‐ray diffraction, total external reflection, scanning electron microscopy and nitrogen adsorption–desorption analysis. Furthermore, both the surface porosity and the mean porosity for the entire volume of the samples were estimated by employing total external reflection measurements and X‐ray reciprocal‐space mapping, respectively. The results clearly indicate that the surface porosity is different from the mean porosity, and the presence of a depth porosity gradient is suggested. To evaluate the porosity gradient in a nondestructive way, a new laboratory method using the grazing‐incidence X‐ray diffraction technique is reported. It is based on the analysis of the X‐ray scattering profiles of the porous layers to obtain the static Debye–Waller factors. In this way, a description of the porosity gradient in a quantitative framework becomes possible, and, as a result, it was shown that the porosity increases exponentially with the X‐ray penetration depth. Moreover, a strong dependence between the porosity gradient and the anodization current was demonstrated. Thus, in the case of the lowest anodization current (e.g. 50 mA cm−2) a variation of only 15% of the porosity from the surface to the interface is found, but when applying a high anodization current of 110 mA cm−2 the porosity close to the bulk interface is almost three times higher than at the surface. [ABSTRACT FROM AUTHOR]

Rationale: Existing methods for the measurement of the 15N/14N isotopic composition of ammonium and nitrate are either only suitable for labelled samples or require considerable sample preparation efforts (or both). Our goal was to modify an existing analytical approach to allow for natural abundance precision levels. Methods: Published reaction protocols were used to convert ammonium into N2 by NaOBr and nitrate into N2O by TiCl3. A membrane inlet system was developed and coupled to an isotope ratio mass spectrometer to allow precise determination of the analytes. Results: Concentrations of ≥35 μmol/L N for both ammonium or nitrate could be analysed for δ15N values with precisions of better than 0.9 mUr. While ammonium analyses exhibited a small concentration dependency and an offset of 2.7 mUr at high ammonium concentrations irrespective of the standard isotopic composition, nitrate analysis showed no offset but a blank contribution visible at very low concentrations. Conclusions: The presented method is capable of fast measurement of δ15N values in ammonium and nitrate from aqueous samples with reasonable accuracy at natural abundance levels. It will thus facilitate the application of isotopic methods to studies of nitrogen cycling in ecosystems. [ABSTRACT FROM AUTHOR]

Rationale: Due to isotope fractionations during partial nitrogen release from minerals and rocks, the complete extraction of nitrogen for analysis is crucial to ensure high‐quality nitrogen isotopic data. However, the appropriate nitrogen extraction conditions (e.g. temperature, duration) have not been established for most silicate minerals and rocks. Methods: Nitrogen in a number of common minerals and rocks was extracted using the most robust sealed‐tube offline combustion techniques, purified and quantified in a custom‐made metal manifold, and carried by helium gas to an isotope ratio mass spectrometer for isotopic measurement at nanomolar nitrogen level. Each mineral or rock was combusted in a variety of temperature and duration conditions to compare the nitrogen yields and isotopic compositions. Results: The nitrogen yields and isotopic compositions of minerals and rocks are strongly affected by combustion temperature and duration. The optimal combustion temperature is lowest for cyclosilicate minerals, followed by phyllosilicate, tectosilicate and inosilicate minerals. Preheating of samples can induce significant nitrogen loss and δ15N shift. Heating of samples above their optimal temperatures may cause nitrogen re‐assimilation by the residual mineral or rock. Conclusions: Each mineral or rock has a characteristic optimal temperature and duration for complete nitrogen release. Preheating, under‐heating or over‐heating can cause nitrogen loss and isotopic shift. Therefore, we recommend using the offline combustion techniques and the optimal combustion conditions obtained in this study for nitrogen quantification and isotopic analysis of silicate minerals and rocks. [ABSTRACT FROM AUTHOR]

Nonthermal plasma (NTP) provides a novel approach to developing renewable and efficient nitrogen fixation (NF) technology. However, the efficiency optimization of NTP-assisted NF (NTP-NF) remains challenging due to the elusive ultra-fast plasma process, especially in packed-bed dielectric barrier discharge (PB-DBD). Our work presents a unique view on how to optimize the efficiency of NTP-NF based on precise studies of plasma dynamics and chemistry by developing a novel nanosecond pulse driving PB-DBD model. 2D plasma dynamics show that the plasma propagates in the form of surface ionization waves coupled with filamentary micro-discharge. Electron heating by high instantaneously applied power determines the development of ionization waves and NO production. Plasma chemistry shows that selectively enhancing the energy of electronically excited dissociation to produce N* is the most efficient way to increase the production of NO. [ABSTRACT FROM AUTHOR]

To substitute the energy‐intensive Haber‐Bosch process for the synthesis of ammonia, some labile techniques, such as photocatalysis, electrocatalysis, photoelectrocatalysis, and photothermocatalysis, have emerged and attracted intense research interest. However, the contamination of the reaction system is one of the major concerns on how to reliably and accurately evaluate the performance of these catalysts, which is why various control studies are involved. Isotopic labeling studies are one of the most reliable control strategies in nitrogen fixation experiments, to ensure that N2 is exclusively the source of the generated ammonia. As a convenient, sensitive and accurate technique distinguished with a quantitative atomic mass resolution, liquid chromatography‐mass spectrometry (LC‐MS) has been extensively employed for the detection of ammonia in aqueous electrolyte systems. However, the previous work protocols for 15N2 isotopic analysis using LC‐MS either involved hazardous procedures which could potentially damage the instrument, or lacked in their experimental verification using real samples. Herein, a safe, reproducible and economical protocol for the detection of ammonia using LC‐MS is presented, exhibiting an exponentially steep progressive detectivity of 15N abundance, well verified with a series of experimental results for nitrogen reduction reactions. This is expected to provide a prudent cost‐effective and sustainable gateway into isotopic analysis. [ABSTRACT FROM AUTHOR]

Paenibacillus durus strain ATCC 35681T is a Gram‐positive diazotroph that displayed capability of fixing nitrogen even in the presence of nitrate or ammonium. However, the nitrogen fixation activity was detected only at day 1 of growth when cultured in liquid nitrogen‐enriched medium. The transcripts of all the nifH homologues were present throughout the 9‐day study. When grown in nitrogen‐depleted medium, nitrogenase activities occurred from day 1 until day 6 and the nifH transcripts were also present during the course of the study albeit at different levels. In both studies, the absence of nitrogen fixation activity regardless of the presence of the nifH transcripts raised the possibility of a post‐transcriptional or post‐translational regulation of the system. A putative SigA box sequence was found upstream of the transcription start site of nifB1, the first gene in the major nitrogen fixation cluster. The upstream region of nifB2 showed a promoter recognizable by SigE, a sigma factor normally involved in sporulation. [ABSTRACT FROM AUTHOR]

An electron-hole self-compensation effect is revealed and confirmed in nitrogen doped Magnéli phase TinO2n-1 (n = 7, 8, and 9) by using hybrid density functional theory calculations. We found that the self-compensation effect between the free electrons in Magnéli phase TinO2n-1 (n = 7, 8, and 9) and the holes induced by p-type nitrogen doping could not only prevent the recombination of photo-generated electron-hole pairs, but also lead to an effective bandgap reduction. This novel electron-hole self-compensation effect may provide a new approach for bandgap engineering of Magnéli phase metal suboxides. [ABSTRACT FROM AUTHOR]

Accurate modeling of high-temperature hypersonic flows in the atmosphere requires consideration of collision-induced dissociation of molecular species and energy transfer between the translational and internal modes of the gas molecules. Here, we describe a study of the N2 + N2→N2 + 2N and N2 + N2→4N nitrogen dissociation reactions using the quasiclassical trajectory (QCT) method. The simulations used a new potential energy surface for the N4 system; the surface is an improved version of one that was presented previously. In the QCT calculations, initial conditions were determined based on a two-temperature model that approximately separates the translational-rotational temperature from the vibrational temperature of the N2 diatoms. Five values from 8000 K to 30000 K were considered for each of the two temperatures. Over 2.4 × 109 trajectories were calculated. We present results for ensemble-averaged dissociation rate constants as functions of the translational-rotational temperature T and the vibrational temperature T v. The rate constant depends more strongly on T when T v is low, and it depends more strongly on T v when T is low. Quasibound reactant states contribute significantly to the rate constants, as do exchange processes at higher temperatures. We discuss two sets of runs in detail: an equilibrium test set in which T = T v and a nonequilibrium test set in which T v < T. In the equilibrium test set, high-v and moderately-low-j molecules contribute most significantly to the overall dissociation rate, and this state specificity becomes stronger as the temperature decreases. Dissociating trajectories tend to result in a major loss of vibrational energy and a minor loss of rotational energy. In the nonequilibrium test set, as T v decreases while T is fixed, higher-j molecules contribute more significantly to the dissociation rate, dissociating trajectories tend to result in a greater rotational energy loss, and the dissociation probability's dependence on v weakens. In this way, as T v decreases, rotational energy appears to compensate for the decline in average vibrational energy in promoting dissociation. In both the equilibrium and nonequilibrium test sets, in every case, the average total internal energy loss in the dissociating trajectories is between 10.2 and 11.0 eV, slightly larger than the equilibrium potential energy change of N2 dissociation. [ABSTRACT FROM AUTHOR]

This paper reports the growth of silicon nanocrystals (SiNCs) from SiH4–O2 plasma chemistry. The formation of an oxynitride was avoided by using O2 instead of the widely used N2O as precursor. X-ray photoelectron spectroscopy is used to prove the absence of nitrogen in the layers and determine the film stoichiometry. It is shown that the Si rich film growth is achieved via nonequilibrium deposition that resembles a interphase clusters mixture model. Photoluminescence and Fourier transformed infrared spectroscopy are used to monitor the formation process of the SiNCs, to reveal that the phase separation is completed at lower temperatures as for SiNCs based on oxynitrides. Additionally, transmission electron microscopy proves that the SiNC sizes are well controllable by superlattice configuration, and as a result, the optical emission band of the Si nanocrystal can be tuned over a wide range. [ABSTRACT FROM AUTHOR]

Sorghum [Sorghum bicolor (L.) Moench] has been receiving attention as a feedstock for biomass energy. Since nitrogen (N) significantly affects the plant biomass production, diagnosing the N status of sorghum during its growth would be significant. Therefore, in this study, we analyzed the changes in several physiological parameters of sorghum in response to N limitation, with the aim of identifying candidates of N status biomarkers in this species. Parameters responding early and sensitively to N deficiency were searched in hydroponically cultured seedlings, and their applicability to field conditions was examined. We found that the leaf chlorophyll content measured as a soil-plant analysis development (SPAD) value was promising as a candidate N status biomarker, as it showed responses consistent with N regimes in field conditions in multiple genotypes. A gene expression analysis was capable of detecting N deficiency sensitively at an early stage, although its application to practical situations requires further investigation to identify a suitable sets of marker genes. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) and its by-products are important biological signals in human physiology and pathology particularly in the vascular and immune systems. Thus, in situ determination of the NO-related molecule (NOx) levels using embedded sensors is of high importance particularly in the context of cellular biocompatibility testing. However, NOx analytical reference method dedicated to the evaluation of biomaterial biocompatibility testing is lacking. Herein, we demonstrate a PAPA-NONOate-based reference method for the calibration of NOx sensors. After, the validation of this reference method and its potentialities were demonstrated for the detection of the oxidative stress-related NO secretion of vascular endothelial cells in a 3D tissue issued from 3D printing. Such NOx detection method can be an integral part of cell response to biomaterials. [ABSTRACT FROM AUTHOR]

Selective removal of lignin and other recalcitrant compounds, collectively registered as acid-unhyrolyzable residue (AUR), results in bleaching of leaf litter, but the importance of bleaching in decomposition processes on forest soil has not been fully evaluated. The aims of this study were to elucidate the occurrence of bleached area in decomposing leaf litter and to compare chemical composition between bleached and nonbleached portions in a subtropical forest in Japan. Field incubation of leaf litter was performed over an 18-month period with the litterbag method. The decomposition processes during the first 9 month were characterized by the relatively rapid mass loss and increase of bleached area, whereas the mass loss was slowed down and the bleached area decreased thereafter. Mass loss of leaf tissues was faster and AUR content was lower in bleached than in nonbleached portions, indicating the acceleration of mass loss in bleached leaf tissues by the selective decomposition of recalcitrant compounds. The decrease in carbonyl-C in the bleached portions was associated with the increase of extractable nitrogen. The results suggest that the bleaching plays a dominant role in the transformation and turnover of organic compounds and nitrogen in decomposing leaf litter. [ABSTRACT FROM AUTHOR]

A bimetallic catalyst (Ni/Cu‐MCM‐41) is prepared via co‐condensation method. The latter is characterized by Fourier transform infrared (FT‐IR), X‐ray powder diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDX), diffuse reflectance spectroscopy (DRS), and nitrogen adsorption–desorption analysis. Catalytic performance of Ni/Cu‐MCM‐41 is probed in N‐alkylation of amines with alcohols through a hydrogen autotransfer process. Noteworthy, this catalytic system appears very efficient for synthesis of a range of secondary and tertiary amines in good to excellent isolated yields. Moreover, the catalyst is successfully recovered and reused four times without notable decrease in its activity. [ABSTRACT FROM AUTHOR]

The elemental analyzer-isotope ratio mass spectrometer (EA-IRMS) technique is widely utilized to measure the nitrogen isotope ratio (δ15N) in various environmental samples. However, this method has limitations when analyzing samples with low nitrogen content (e.g., soils, rocks and atmospheric deposition) due to significant sample dilution (>99%) before entering the ion source. To reduce sample size requirement and increase sensitivity, modifications can be made to the elemental analyzer and analytical conditions to transfer more sample gas to the ion source. In this study, we presented four modifications to the EA-IRMS instrument, including the reaction tube, water trap, gas chromatography (GC) column, and inlet splitter connected to ConFlo, along with the analytical conditions of the GC column, carrier gas flow rate, and split ratio for improving sensitivity. The results show that reducing the carrier gas flow rate from 80 to 30 mL/min increased the sensitivity of the EA-IRMS system by twofold. By increasing the split ratio from 3:2 to 3:1, the sensitivity increased from 2.32 Vs/μg N to 3.93 Vs/μg N. The optimized EA-IRMS has a sample size requirement of at least 12 μg N and a standard deviation of <0.2‰ for δ15N analysis. We found that the modifications of the GC column and water trap had a negligible influence on sample peak and measurement and thus were deemed unnecessary. The effective modifications in the study were reducing the carrier gas flow rate and increasing split ratio, which increased the concentration of the analyte gas per unit volume and more efficient sample transfer to the ion source. This upgraded method can provide crucial technical support for environmental samples with low nitrogen content. • New modified EA-IRMS method was developed for trace nitrogen isotope analysis. • The minimum nitrogen requirement was reduced from 28 μg to 12 μg. • New method can improve analysis accuracy and decrease analysis costs. • Nitrogen isotope of varied mass of standards and actual samples are consistent. [ABSTRACT FROM AUTHOR]

In maize, nitrogen (N) stored in leaves is an important internal source for supporting subsequent growth and development. However, the regulation of N fluxes and photosynthesis and the molecular and genotypic regulations that modify them are less clear in source leaves during the vegetative stage. This knowledge is crucial for improving N use efficiency (NUE). By using 15N labeling and transcriptome methods, an analysis of the physiological and molecular basis of leaf N import and export processes and photosynthetic N use efficiency (PNUE) was conducted in two maize hybrids (XY335 and XY696) with different stay-green characteristics during the vegetative stage. Leaf N import and export in XY696 were 45% and 33% greater than those in XY335. However, the PNUE in XY335 was 17% greater than that in XY696 due to the higher net photosynthetic rate (A) and lower SLN. Correspondingly, the chlorophyll content and photosynthesis-related enzyme (PEPc, PEPck, PPDK) activities increased by 18∼30% in XY335. Transcriptome analysis indicated that the expression levels of several N and carbon metabolism-related genes encoding Rubisco, PEPc, Nir, GS and AS were significantly increased or decreased in XY696 in parallel with enzyme activities. Moreover, there was a large difference in the expression abundance of genes encoding nitrate/nitrite transporters and transmembrane proteins. Our results suggest that two hybrids modulate leaf N fluxes and photosynthesis differently by altering gene expression and enzyme activities. Our study contributes to understanding leaf N fluxes and PNUE regulation and serves as a crucial reference for NUE improvement in maize breeding research. [Display omitted] • Leaf N import and export in XY696 were greater compared to XY335. • XY335 showed a higher PNUE as results of high A and low SLN. • Photosynthetic enzyme activities and chlorophyll content were increased in XY335. • Rubisco, NiR, GS and AS changed in transcript level in parallel to activity level. [ABSTRACT FROM AUTHOR]

• Wood was modified via controlled in-situ self-assembly Ag-PW nanospheres. • Excellent flame retardancy and durability with leach test was achieved. • Antimicrobial property was achieved via in-situ self-assembly Ag-PW nanospheres treatment. • The catalytic mechanism of Ag-PW on depolymerization route of conversion of LGO to HMF was verified by DFT calculation. • The possible adsorption mechanism of Ag-PW on wood was proposed. In this work, we present a simple and effective approach to enhance the fire safety and anti-corrosion performance of wood by forming in-situ self-assembled amphiphilic Ag-PW nanospheres (NSP) at room temperature. The morphology and acid capacity of the NSP were optimized by changing the ratio of phosphotungstic acid (HPW) and silver nitrate. The Ag-PW NSP were successfully integrated into the bulk of the wood, resulting in a durable treatment with minimal leaching. Comprehensive characterization techniques, including FTIR, XPS, XRD, SEM, TEM, and nitrogen adsorption–desorption analysis, confirmed the in-situ formation of Ag-PW NSP in the wood. The treatment exhibited low-leaching properties with only 5.89% of Ag-PW1a leaching out. The treated wood demonstrated excellent flame-retardant (FR) properties, as evidenced by a limiting oxygen index value > 28% and easy passage of the UL-94 test, with the formation of a high-density char layer. The flammable pyrolysis products released during combustion were found to be significantly altered, with a change in the depolymerization route of conversion of LGO under acid conditions to HMF, which was verified by DFT calculations. The treated wood also exhibited outstanding anti-corrosion properties, with a mass loss rate of less than 1%, compared to at least 32.3% for bare wood after the anti-white or brown-rot fungus tests. Moreover, the treated wood samples maintained their excellent FR properties even after leaching. Our study provides valuable insights for the rational design of nano-material additives for wood protection, thereby improving the usage of wood resources while mitigating health and environmental hazards. [ABSTRACT FROM AUTHOR]

For the management of eutrophic lakes, watershed nitrogen and phosphorus control is oriented to future water quality. Assessing future nutrient dynamics and the risk of lake eutrophication is necessary. However, current assessments often lack integrated consideration of socioeconomic and climatic factors, which reduces the reference value of the results. In this study, a typical large shallow lake Chaohu, which is highly influenced by human activities, was selected as the study area, and the current and future total nitrogen (TN) and total phosphorus (TP) loading in the basin were analysed using the improved MARINA model, and the risk of water bloom were assessed. The results showed that socioeconomic factors alone varied future TN and TP loading by −24% to 32% and −40% to 34%, respectively, under different development patterns. After considering the effect of increased precipitation, the changes of TN and TP loading became −10% to 163% and −29% to 108%, respectively. The effect on loading reduction under the sustainable development pattern was weakened (58% and 28% for TN and TP loading, respectively) and the increase in loading under the brutal development pattern was significantly amplified (409% and 215% for TN and TP loading, respectively). The adoption of active environmental policies remained an effective way of loading control. However, the risk of water bloom in local lake areas might persist due to factors such as urbanization. Timely and comprehensive assessments can provide managers with more information to identify key factors that contribute to the risk of water blooms and to develop diverse water quality improvement measures. The insights from our study are applicable to other watersheds around the world with similar socio-economic background and climatic conditions. • Analysis of the compounding effect of socio-economic and climatic factors on loading. • Complex impact of precipitation on loading under different development scenarios. • Improved MARINA model to enhance model accuracy and applicability. • Assessing the risk of future water bloom from a local perspective in the lake. [ABSTRACT FROM AUTHOR]

A systematic first principles study is carried out to probe into the activity of graphyne supported Co 13 , Fe 13 and Ni 13 nano-clusters (NCs) towards the reduction of nitrogen (N 2) into ammonia (NH 3). Graphyne is found to highly stabilize the metal nano-clusters on its large pores through an exothermic chemisorption process. Adsorption of N 2 on the graphyne supported NCs are detected to be highly exothermic in both end-on and side-on mode configurations. N 2 becomes more activated via a higher amount of N-N bond stretching when adsorbed in side-on configuration. The activation of the N-N bond is shown to be directly proportional to the amount of charge transfer to the adsorbed N 2 molecule. Thorough analysis of the nitrogen reduction reaction (NRR) on each graphyne supported metal NC reveals that NRR starting from side-on mode N 2 adsorbed configuration prefers the enzymatic pathway though other pathways are possible at the cost of relatively higher overpotential. Only the distal pathway is energetically favoured following the end-on mode N 2 adsorbed configuration. Graphyne supported Co 13 , Fe 13 and Ni 13 NCs are shown to carry out NRR with substantially low overpotential values of 0.24 V, 0.28 V and 0.37 V respectively. The active sites located far from the graphyne substrate are found to be more selective towards NRR with low overpotential than hydrogen evolution reaction. The NCs maintain their structural stability on the graphyne surface throughout the whole reaction process via different pathways showing that graphyne is a potentially very promising substrate material to stabilize the NC electrocatalysts and to improve their electrocatalytic activities towards NRR. [Display omitted] • NRR is studied theoretically for graphyne supported Co 13 , Fe 13 and Ni 13 nano-clusters. • The interaction of the nano-clusters with the graphyne substrate is investigated. • Electronic properties of the adsorbed nano-clusters and N 2 molecules in explored. • The selectivity of the chosen electrocatalyst systems towards NRR is established. [ABSTRACT FROM AUTHOR]

[Display omitted] • Significant removal capability of inorganic N was detected in strain DN3. • N assimilation dominated the NH 4 +-N, NO 3 −-N, and NO 2 −-N removal process. • Hetertrophic nitrification pathway of DN3 was revealed: NH 4 + → NH 2 OH → NO → N 2 O → N 2. • N eliminating assays under various conditions showed bacterial potential application. • A candidate for treatment of mariculture wastewater was provided by this work. Recently, the functional microorganisms capable of eliminating nitrogenous waste have been applied in mariculture systems. As a potential candidate for treating mariculture wastewater, strain DN3 eliminated 100% of ammonia and nitrate and 96.61%–100% of nitrite within 72 h, when single nitrogen sources at concentrations of 0–50 mg/L. Strain DN3 also exhibited the efficient removal performance of mixed-form nitrogen (ammonia, nitrate, and nitrite) at salinity 30 ‰, C/N ratio 20, and 180 rpm. The nitrogen assimilation pathway dominated inorganic nitrogen metabolism, with less nitrogen (14.23%-25.02% of TN) lost into the air via nitrification and denitrification, based on nitrogen balance analysis. Moreover, the bacterial nitrification pathway was explored by enzymatic assays and inhibition assays. These complex nitrogen assimilation and dissimilation processes were further revealed by bacterial genome analysis. These results provide important insight into nitrogen metabolism of Halomonas sp. and theoretical support for treating mariculture wastewater with strain DN3. [ABSTRACT FROM AUTHOR]

Producing enough food to simultaneously address food shortage and agro-environmental pollution problems attracts attention globally. To quantify the risks of nutrition crisis to food security and the agro-environment under current agricultural policies in China, this study evaluates and predict the spatiotemporal patterns of nitrogen (N) flows during 1949–2050 through material flow analysis (MFA) and spatial analysis methods. The results show that (1) the crop harvest (including grains, fruits and vegetables) in China increased by a factor of 8.12 from 1949 to 2019, accompanied by a large amount of N loss to the environment. Compared to 1949, N runoff increased 1.23 times in 1979 and 3.43 times in 1999 after which time agricultural pollution control policy achieved initial results, and the crop harvest increased steadily. (2) At the national average level, crop production will increase by 58.60% in 2050, which is higher than the food security threshold while N loss to the environment will be lower than the agro-environmental risk threshold. Under the current agricultural policy, the win-win goals of crop production increase and pollution control can be realized in China. (3) China has obvious temporal and spatial differences in N flows, for which four regions has been divided. Region II, mainly located in Yangtze River Economic Belt, is a high-risk area for N loss. By 2050, environmental pollution can be controlled under the current agricultural policies. However, crop production will only increase by 10% compared with its historical high value, lower than food security threshold. It is necessary to implement more targeted management of high-risk areas by adopting methods such as fallowing or construction of pollution buffer zones while improving N fertilizer use efficiency. For region III, the impact of N loss on the environment has always been at a low level, so there is still great room for increasing future crop production in this region. On average, China will be able to achieve green and sustainable development for agriculture nationally, but there are remaining food security risks in high N loss areas. More targeted N management strategies should be applied to achieve better goals in the future. [Display omitted] • Crop harvest increased by 8.12 times, accompanied by a large amount of N losses. • Compare to 2014, N runoff in 2019 reduced by 15% for the environmental policies. • Win-win goals for food security and pollution control can be reached in 2050. • To achieve better goals, 4 regions are divided to apply more targeted N management strategies. [ABSTRACT FROM AUTHOR]

Recovery of coalbed methane (CBM) is of great significance for environmental protection, safe production of coal mines, and clean energy supply. To reveal the efficiency difference of different nitrogen reverse Brayton cycles (N 2 -RBC) for recovering CBM and identify the most efficient N 2 -RBC in terms of energy consumption and economy, four typical N 2 -RBCs were studied numerically. Each process was optimized globally by performing genetic algorithm (GA) procedure, using specific power consumption (SPC) per unit product as the objective function. Pinch analysis approach was used to improve N 2 -RBC. All proposed processes were assessed comprehensively concerning efficiency, exergy loss, and economy. It is found that the slope of the hot/cold composite curve is greatly influenced by the material streams' mass flow rate while slightly affected by the specific heat except for the region near critical parameters. The parallel arrangement of expanders reaches a better match between hot and cold composite curves than the series. For the liquefaction capacity of 10 tons per day, the liquefaction process using parallel N 2 -RBC achieves the lowest SPC of 0.72 kWh·kg−1 and the highest figure of merit of 31.11%. It also has the lowest exergy loss of 180.1 kW and a total investment of 4047.76 k$, respectively. • Four typical N 2 -RBCs are assessed concerning efficiency, exergy loss, and economy. • Parallel N 2 -RBC is evaluated as the most profitable. • Factors affecting the shape of the composite curve are investigated. • Pinch analysis approach is used to guide improvement of N 2 -RBC for the first time. • Parallel N 2 -RBC achieves more excellent match between composite curves than series. [ABSTRACT FROM AUTHOR]

Investigation of surface recombination activity of nitrogen on certain materials is crucial in the design of hypersonic re-entry vehicles. In the present work, an experimental study using a conventional shock tube facility has been conducted to investigate the phenomena of nitrogen recombination. Stagnation heat-transfer measurements were conducted behind reflected shock waves in a dissociated shock-tube flow for a mixture of 20% nitrogen and 80% argon. A platinum thin-film gauge was used to measure the stagnation heat-transfer in a shock heated gas mixture under a well-defined test condition. The surface of the heat-transfer gauge was coated with silicon dioxide (SiO 2), the principal material used in thermal protection systems (TPS) for the hypersonic vehicles. Spectroscopic analyses were performed for in-depth characterization of the initial surface condition of the test specimen. Recombination activity behavior of nitrogen was evaluated by combining the heat-transfer data with catalytic heat transfer theories. The nitrogen recombination efficiency of silicon dioxide is found to be from 0.0026 to 0.035 at surface roughness factors of 1.01 to 1.10. Compared to the oxygen recombination activity, the nitrogen recombination activity showed a more than five times higher sensitivity to the roughness factor of the SiO 2 -coated surface. • Recombination activity behavior of nitrogen on SiO 2 surface is evaluated. • Stagnation heat-transfer data are analyzed using catalytic heat-transfer theories. • Initial surface conditions of test specimen are examined by spectroscopic analysis. • Nitrogen catalytic efficiency of SiO 2 surface is deduced to be from 0.0026 to 0.035. • Nitrogen recombination is more favorable to change in SiO 2 roughness than oxygen. [ABSTRACT FROM AUTHOR]

• Acidity of HZSM-5 is controlled by mixing HZSM-5 and Na-modified HZSM-5. • Na-modification of HZSM-5 change only acidity without change textural properties. • Mixing HZSM-5 and Na-modified HZSM-5 decreases strong acid sites of catalyst with minimizing reduction of weak acid sites. • Catalyst prepared with 50 wt% HZSM-5 and 50 wt% Na-modified HZSM-5 has higher catalytic activity than conventional HZSM-5. In this study, Zeolite Socony Mobil–5 (ZSM-5) was modified by ion exchange with sodium ion to control the strong acid sites of catalyst, and the specific control of strong acid sites was carried out by mixing HZSM-5 and NaZSM-5. The characteristics of the catalyst were analyzed using X-ray diffraction, NH 3 -temperature programmed desorption, pyridine adsorption Fourier transform infrared spectroscopy, and nitrogen adsorption-desorption analysis. The catalysts were used for the catalytic reaction with methylcyclohexane under supercritical condition (500 °C and 5.0 MPa). After reaction, the liquid product was analyzed using gas chromatography-mass spectrometry, and the spent catalyst was analyzed using thermogravimetric analysis to measure coke formation. In the catalytic reaction, conventional HZSM-5 was deactivated quickly with time (59.6 % of deactivation rate), but the mixed catalyst with NaZSM-5 was deactivated more slowly than HZSM-5. In addition, the mixed catalyst having the same mass ratio for HZSM-5 and NaZSM-5 showed the lowest deactivation rate of 37.4 % after 60 min. The mixed catalyst produced 10.1 wt% coke and it was lower than HZSM-5 (12.5 wt%). The catalytic robustness of HZSM-5 could be enhanced by mixing with NaZSM-5. [ABSTRACT FROM AUTHOR]

The unnecessary application of nitrogen could negatively impact both the yield and quality of crops, and could also lead to nitrate leaching and soil pollution. The objective of this study was to investigate the effects of the optimized nitrogen application on 15N accumulation, utilization and distribution of processing tomato in China. Through field experiments with 15N and consisted two treatments: optimized nitrogen application (NY) and no nitrogen application (N0). The results showed that the absorption efficiency of applied fertilizer nitrogen was 46%. In processing tomato plants, 128.9 kg ha−1 of nitrogen came from applied fertilizer, while the remainder of the nitrogen (177.6 kg ha−1) came from the soil. The processing tomato fully absorbed the soil nitrogen, which reduced the nitrogen loss rate and resulted in higher production of dry matter. In the harvest stage. The residual percentage in soil of applied fertilizer nitrogen was 34%, which was mainly distributed in the 0-40 cm soil layer. This reduced the leaching of nitrogen and was conducive to the reuse of crops in the next year. This study provides a reference for the development of precise nitrogen management techniques using drip irrigation methods in arid areas.. [ABSTRACT FROM AUTHOR]

Cooling of machining operations by liquid nitrogen is a promising approach for reducing cutting temperatures, increasing tool life and improving the workpiece surface integrity. Unfortunately, the cooling fluid tends to evaporate within the supply channel. This induces process variations and hinders the use of nitrogen cooling in commercial applications. In this work, the coolant is applied via the tool's rake face during orthogonal turning of Ti-6Al-4V. The effect of a nitrogen supply pressure adjustment and a subcooler usage—proposed here for the first time for machining—is analyzed in terms of process forces, tool temperatures and wear patterns, taken dry cutting as a reference. Thereby, reliable cooling strategies are identified for cryogenic cutting. [ABSTRACT FROM AUTHOR]

According to ecological theory, two species cannot occupy the same niche. Using nitrogen isotope analyses (δ15N) of amino acids, we tested the extent to which two sympatric deposit‐feeding amphipods, Monoporeia affinis and Pontoporeia femorata, partition their trophic resources. We found that trophic position (TP) and resynthesis index (∑V; a proxy for degradation status of ingested material prior to assimilation by the consumer) differ between species. The surface‐feeding M. affinis had higher TP and intermediate ∑V, both pointing to a large contribution of metazoans in its diet. P. femorata, which feeds in the subsurface layers, had lower TP and a bimodal distribution of the ∑V values, supporting previous experimental evidence of a larger feeding niche. We also evaluated whether TP and ∑V values have consequences for amphipod fecundity and embryo viability and found that embryo viability in M. affinis was negatively linked to TP. Our results indicate that the amino acid‐δ15N data paired with information about reproductive status are useful for detecting differences in the trophic ecology of sympatric amphipods. [ABSTRACT FROM AUTHOR]

A simple microwave method was employed to prepare silica-doped mesoporous zirconia nanoparticles, SiO2/ZrO2 (SiZr) catalysts under various Si amount and then characterized by X-ray diffraction, nitrogen adsorption–desorption analyses, Fourier-transform infrared, electron spin resonance, ultraviolet–visible diffuse reflectance spectroscopy and photoluminescence analyses. The lower amount of Si fully stabilized the ZrO2 in the tetragonal phase (t-ZrO2), but the higher amount of Si occupied oxygen vacancies (OV) in the SiZr lattice to disrupt the catalysts with introduce low content of monoclinic phase. The catalyst activity towards on photodegradation of 2-chlorophenol (2-CP) was ranked in the following order: 1SiZr (92%) > TiO2 (73%) > 2SiZr (67%) > 3SiZr (64%) > 4SiZr (56%) > ZrO2 (51%). This result demonstrated that 1SiZr gave the highest degradation percentage of 10 mg L−1 2-CP at pH 5 using 0.375 g L−1 catalyst under visible light irradation within 4 h. The highest photoactivity of 1SiZr is due to the larger surface area and crystallite size, which resulted in a good surface contact with light and thus accelerated the photocatalytic activity. Additionally, the highest amount of OV possesed by 1 SiZr effectively suppressed the electron–hole recombination by acting as an electron acceptors, which consequently affected the t-ZrO2 stabilization as well as the catalytic activity. The kinetics of photocatalytic degradation of 2-CP correlated with pseudo-first order model, with the surface reaction as the controlling step. The photogenerated hole was the most active species as confirmed by effect of scavenger study. The 1SiZr maintained the photocatalytic activities after five runs and has a great capability in degrading of various phenols derivatives, indicating its potential use in the phenol-based wastewater treatment. [ABSTRACT FROM AUTHOR]

Submarine canyons can facilitate the transfer of land‐derived organic matter to the deep sea. Here, we investigated links between variability in organic matter availability from land and marine sources and infauna communities in two contrasting canyon systems off New Zealand and used stable isotope analyses to identify potential food sources of benthic invertebrates. Kaikōura Canyon, a steep, short canyon close to the shore, was characterized by high food availability and varying proportions of marine‐ and land‐derived organic matter, whereas Hokitika Canyon, a narrow and lower‐gradient canyon that extends further from the coast, was characterized by low food availability and mostly land‐derived sediment organic matter throughout. Both macrofaunal and meiofaunal abundance and biomass were greater in Kaikōura Canyon than in Hokitika Canyon. Correlation analyses suggested that land‐derived organic matter may contribute to increased meiofaunal abundance in Kaikōura Canyon. Carbon and nitrogen isotopic analyses, however, did not provide unequivocal support for the uptake of land‐derived material by large benthic invertebrates in Kaikōura Canyon. Infaunal abundance and biomass were low throughout Hokitika Canyon despite similar concentrations of land‐derived organic matter in sediments of both canyons, which suggests that variations in marine‐derived organic matter inputs is the main driver of community differences among canyons. Refractory vascular plant material by itself may not provide an adequate food supply to infaunal organisms, but may represent a complementary food resource when more labile marine phytodetritus is also readily available. [ABSTRACT FROM AUTHOR]

Rationale: The presence of lipids in animal tissues can influence the interpretation of stable isotope data, particularly in lipid‐rich tissues such as the skin and muscle of marine mammals. The traditionally employed chloroform–methanol delipidation protocol has the potential to alter δ15N values in proteinaceous tissues. Our objective was to determine whether the use of cyclohexane could be an alternative extraction method, effectively removing lipids without altering δ15N values. Methods: Kidney, liver, muscle, and skin samples were collected from beach‐cast Sowerby's beaked whales (Mesoplodon bidens). Control subsamples were processed without delipidation extraction, and duplicate subsamples were extracted with either chloroform–methanol or cyclohexane. δ13C, δ15N, and C:N values were determined by continuous‐flow elemental analysis isotope ratio mass spectrometry. Paired Wilcoxon tests were used to evaluate the change in isotope ratios after extraction, and unpaired Wilcoxon tests were used to evaluate differences in isotope ratios between extractions. Results: Use of cyclohexane is an effective delipidation technique for tissues with low and moderate lipid content. Chemical delipidation influenced δ15N values; extracted samples generally showed an increase in δ15N values which varied from 0.0‰ to 1.7‰. Chloroform–methanol extraction resulted in alterations to δ15N values greater than the analytical precision for all analyzed tissues. Changes to δ15N values after cyclohexane extraction were at or near the analytical precision for liver and muscle but greater than the analytical precision for kidney and skin. Conclusions: We recommend processing duplicate subsamples for stable isotope analysis, one with and one without extraction, in order to obtain accurate values for each isotope ratio. Prolonged chemical extractions are not necessary to effectively remove lipids. When samples are limited, we suggest using cyclohexane for tissues with low or moderate lipid content, and chloroform–methanol for lipid‐rich tissues. [ABSTRACT FROM AUTHOR]

Noble gases and nitrogen are investigated in eight individual chondrules of the Dhajala H3.8 chondrite. The mean cosmic ray exposure age of the chondrules using 21Ne and 38Ar is 5.9 ± 3.0 Ma. There is no significant evidence of a pre‐exposure for these chondrules. All the measured chondrules contain variable amounts of radiogenic 129Xe. Noble gas analysis indicates Q‐type gas incorporated in the chondrules. The chondrules have variable amounts of N2. The chondrules have distinct trapped N isotopic composition (δ15Nt varies from −24.1 ± 8.4‰ to 89.1 ± 12.7‰), which is inconsistent with Q‐gas and solar wind. These inconsistencies can be considered preliminary evidence in support of multiple trapped components in the chondrules. A heavy N signature component is observed in the chondrules studied contrasted with the solar wind composition. There is no correlation between the concentration of N2 and noble gases. Derivations of variable nitrogen observed in Dhajala (H3.8) chondrules reflect the gas captured at the time of formation, having heterogeneous isotopic signature in the nebula. [ABSTRACT FROM AUTHOR]

【Objective】Analysis of nitrogen fertilizer efficiency and yield of six high-quality conventional rice varieties at different nitrogen applications was conducted. It provides theoretical basis for the production selection of nitrogen-efficient varieties of high-quality rice and reasonable reduction of nitrogen fertilizer application.【Method】The test varieties are Guixiang 18,Guiyu 12,Guiyu 9,Guiyu 11,Guiyu 18 and Guiyu 8.The control variety is Liushayouzhan 202. Set four nitrogen fertilizer application levels:0（no nitrogen）,112.5（low-medium nitrogen）,150（conventional nitrogen） and 187.5（high nitrogen） kg/hm2(The treatment sequences are N0,N7.5,N10.0 and N12.5).Determination and analysis on the nitrogen utilization of each varieties by measuring physiological efficiency（PE）,agronomic efficiency（AE）,recovery efficiency（RE）,partial factor productivity（PFP）, and yield difference was compared and nitrogen efficiency was evaluated.【Result】The physiological efficiency and agronomic efficiency of nitrogen fertilizer of six high quality conventional rice varieties were the highest under N7.5 and all of them were significantly higher than N12.5（P<0.05,the same as below）.There was no significant difference in the recovery efficiency of nitrogen fertilizer of Guiyu 12,Guiyu 11,and Guiyu 18 among various nitrogen applications（P>0.05,the same as below）.The recovery efficiency of nitrogen fertilizer of Guixiang 18,Guiyu 9 and Guiyu8 were the highest at N10.0,N7.5 and N12.5.The partial factor productivity of nitrogen fertilizer of tested varieties decreased significantly with the increase of nitrogen application. There was no significant difference in yield at N7.5,N10.0 and N12.5 of Guixiang 18,Guiyu 12,Guiyu 9 and Guiyu 11. The yield of Guiyu 18 and Guiyu 8 were significantly higher than that when N7.5 compared to N12.5.The yield of six high-quality conventional rice varieties at N7.5 were significantly higher than that of CK.It is higher than that of CK under treatment of N10.0 and N12.5. It showed that the yield of these 6 varieties could be maintained under the condition of 25 % reduction of nitrogen application.Grains per spike,filled-grain percentage and 1000-grain weight of six high-quality conventional rice varieties are no significantly different at N7.5,N10.0 and N12.5.There was no significant difference in the effective spike of Guixiang 18,Guiyu 12,Guiyu 11 and Guiyu 8 at N7.5,N10.0 and N12.5.The effective spike of Guiyu 9 was not significantly different between N7.5 and N10.0.The effective spike number of Guiyu 18 was not significantly different between N7.5 and N12.5.The effective spike of CK increased significantly with the increase of nitrogen application.The effective spike of these six varieties remained high at low nitrogen level(N7.5),which was the main reason for the high yield at reduced nitrogen application.【Conclusion】The yield of six varieties of high quality conventional rice in Guangxi at low nitrogen level（nitrogen application 112.5 kg/hm2） can reach or exceed the yield at the level of normal nitrogen（nitrogen application 150 kg/hm2） and high nitrogen（nitrogen application 187.5 kg/hm2）,and it is significantly higher than the yield of the control varieties in the Guangxi regional test with the same ripening group under normal nitrogen application. These varieties are nitrogen-efficient varieties that meet the yield requirements of nitrogen-efficient varieties in production promotion. [ABSTRACT FROM AUTHOR]

Stable carbon and nitrogen isotope analysis of 15 individuals buried closed to Bayanbulag site or the Shouxiangcheng fortress in southern Mongolia revealed complex dietary features. Only one individual had a diet similar to that of the pastoral population in northern China, while the others, who had varying carbon isotope values and low nitrogen values, might have been from different agricultural areas. 14C dating results suggest that the earliest interment could be much earlier than the building of Shouxiangcheng fortress recorded in Han texts. Analysis of the burial arrangement further confirmed that these deceased were not buried at the same time. [ABSTRACT FROM AUTHOR]

Rationale: The nitrogen isotopic ratio of nitrate (δ15N‐NO3− value) is a critical parameter for understanding nitrogen biogeochemical cycling in aquatic systems. Current approaches to the determination of δ15N‐NO3− values involve time‐intensive handling procedures, the use of toxic chemicals and complicated microbial incubation. Methods: A chemical reduction method for measuring the δ15N‐NO3− values of aquatic samples was established. Nitrate was first quantitatively reduced to nitrite in a column filled with copper‐coated cadmium granules, and the produced nitrite further reduced to nitrous oxide gas with hydroxylamine hydrochloride. The nitrogen isotope ratio of the produced nitrous oxide was measured using a continuous‐flow isotope ratio mass spectrometer coupled with a purge and cryogenic trap system. Results: The optimized experimental conditions were: solution acidity, H+ concentration of 0.46 M, pH = 0.34; dosage of hydroxylamine, molar ratio of NH2OH to NO2− of 4; reaction temperature, 45°C; and reaction time, 14–16 h. No salt effect was found for this method. The reproducibility of the δ15N‐NO3− value for the laboratory standard was better than 0.3‰ for long‐term measurements (20 nmol NO3− requirement). Conclusions: This method provides a reliable approach for the determination of δ15N‐NO3− values at natural abundance. It provides (1) high measurement accuracy, (2) ease of operation, (3) environmental‐friendly procedure (less toxic regents used), and (4) suitability for both freshwater and saline water samples. [ABSTRACT FROM AUTHOR]

Instead of the conventional approach to sectioning tooth dentine horizontally for isotope analysis, a new serial sampling strategy has been developed recently. This new method considers the developmental direction of growth lines in dentine when samples are sectioned. It can therefore provide more precise and detailed information about an individual's dietary history, including breastfeeding/weaning patterns, infant feeding experiences, and dietary shifts throughout the early life of an individual. In order to enhance our understanding of human groups in ancient Sichuan, it is practical and necessary to apply this new technique to archaeological samples from this region. In this study, carbon and nitrogen isotope compositions of bone and serial dentinal collagen from two Yingpanshan human individuals (M32 and M40) were analysed and compared, in order to reveal the dietary history during their lifetime. Results indicate that their long‐term averaged diets after childhood consisted of both C3 and C4‐type foods, predominantly the former. The contribution of animal protein to the childhood diet of individual M40, between the ages of 3.0 and 7.5, was similar to his long‐term averaged diet after childhood. He had also consumed more millets during the childhood. By comparison, individual M32 consumed more animal protein and likely also more C3‐type foods between the ages of 4.5 and 13.5 than after childhood. Little variations in δ15N dentinal collagen of each individual suggest that the relative consumption of animal to plant foods in their respective diets was more or less consistent in their childhood. However, the larger variations in the δ13C values of dentine samples show that the proportion of C3 and C4‐plant foods in their respective diets varied at different phases in their childhood. The variations are probably related to environmental factors and/or human behaviour. The dietary history and weaning practices revealed by using this technique also indicate that the two individuals might have been non‐locals or received some foods that originated from the outside. [ABSTRACT FROM AUTHOR]

Two kinds of hydroxypropyl β-cyclodextrin nanohybrid monoliths were synthesized and applied in capillary electrochromatography with UV detection. One column was fabricated by concurrently using glycidyl methacrylate-bonded hydroxypropyl β-cyclodextrin (GMA-HP-β-CD), sodium 3-mercaptopropanesulphonate, and alkoxysilanes in the "one-pot" process. The other was prepared by free radical polymerization of GMA-HP-β-CD, vinylmethylcyclosiloxane, ethylene dimethacrylate, and 2-acrylamido-2-methyl propane sulfonic acid. Compared to the former hybrid monolith, the latter one displayed improved enantiomeric separation. For ten adrenergic drugs, six anticholinergic drugs, two antidepressants, six azoles, and one antihistamine enantiomeric separation was obtained on the monolith synthesized by free radical polymerization. Twelve out of twenty-five drugs were baseline-separated. Especially, anisodamine with two chiral centers was successfully separated with resolution values of 3.06, 2.11, and 2.17. The nanohybrid monoliths were characterized by optical microscopy, scanning electron microscopy, FT-IR, nitrogen adsorption analysis, and thermogravimetric analysis. Relative standard deviation values less than 5% were obtained through run-to-run, day-to-day, and column-to-column investigations (n = 3). [ABSTRACT FROM AUTHOR]

The purpose of this paper is to present the third stage of regeneration for ecat: deactivated or equilibrium catalysts which are waste from fluidized catalytic cracking (FCC) units. This stage is going to compose a complete circular economy (CE) model and increase the life cycle of the catalyst. The third stage of regeneration, after the adsorption process for sulfur and nitrogen compounds from real diesel, was assessed using as solvents: acetone (propanone), ethanol, benzene and toluene. For sulfur and nitrogen compounds, ethanol achieved the best performance. The variations of physical and chemical properties of regenerated ecats in the cycles of adsorption and desorption were evaluated using x-ray diffraction, x-ray fluorescence, nitrogen adsorptiondesorpion, thermogravimetric and differential thermal analysis, scanning electron microscopy and Fourier-transform infrared spectroscopy. The recovery rate over four cycles is superior for sulfur compounds. After all cycles, ecat-R- -SA exhibited 5.09% reduction in the recovery for sulfur and 24.58% reduction in the recovery for nitrogen. The nitrogen adsorption-desorption analysis suggests the adsorption of compounds by ecat-R may be more correlated with the adsorption sites than with specific area. Overall, the results of this work are promising and allows for ecat to integrate a complete CE model. [ABSTRACT FROM AUTHOR]