Advanced glycation end products induce neural tube defects through elevating oxidative stress in mice

Our previous study showed an association between advanced glycation end products （AGEs） and neural tube defects （NTDs）. To understand the molecular mechanisms underlying the effect of AGEs on neural tube development, C57BL/6 female mice were fed for 4 weeks with com- mercial food containing 3% advanced glycation end product bovine serum albumin （AGE-BSA） or 3% bovine serum albumin （BSA） as a control. After mating mice, oxidative stress markers including malondialdehyde and H202 were measured at embryonic day 7.5 （E7.5） of ges- tation, and the level of intracellular reactive oxygen species （ROS） in embryonic cells was determined at E8.5. In addition to evaluating NTDs, an enzyme-linked immunosorbent assay was used to determine the effect of embryonic protein administration on the N-（carboxymethyl） lysine reactivity of acid and carboxyethyl lysine antibodies at E10.5. The results showed a remarkable increase in the incidence of NTDs at El0.5 in embryos of mice fed with AGE-BSA （no hyperglycemia） compared with control mice. Moreover, embryonic protein administration resulted in a noticeable increase in the reactivity of N-（carboxymethyl） lysine and N（ε）-（carboxyethyl） lysine antibodies. Malondialdehyde and H2O2 levels in embryonic cells were increased at E7.5, followed by increased intracellular ROS levels at E8.5. Vitamin E supplementation could partially recover these phenomena. Collectively, these results suggest that AGE-BSA could induce NTDs in the absence of hyperglycemia by an underlying mechanism that is at least partially associated with its capacity to increase embryonic oxidative stress levels.

Interhemispheric and longitudinal differences in the ionosphere-thermosphere coupling process during the May 2024 superstorm

Geomagnetic storm events have a strong influence on the ionosphere–thermosphere(I-T)coupling system.Analyzing the regional response process of the I-T system and its differences across the northern and southern hemispheres is an important but challenging task.In this study,we used a combination of multiple observations and a model simulation to examine the north–south hemispheric difference in the I-T coupling system in the American and Asian sectors during the geomagnetic superstorm that occurred in May 2024.Observations of the total electron content(TEC)showed that the Asian sector had negative storms in the northern hemisphere and positive storms in the southern hemisphere,a process that exacerbated the hemispheric differences in the TEC.However,both hemispheres of the American sector showed negative storms.The thermospheric composition changes also differed between the two sectors,and their variation could partially explain the hemispheric differences caused by positive and negative storms.Moreover,the influence of the thermospheric density change was less than that of the thermospheric composition.Finally,the dynamic effect of the thermospheric wind and the plasma transport processes strongly modulated the north–south differences in the TEC at nighttime in the American and Asian sectors,respectively,during this superstorm.

Microstructure and microwave dielectric properties of CaO-B_2O_3-SiO_2 glass ceramics with various B_2O_3 contents

The effects of B2O3 addition on both the sintering behavior and microwave dielectric properties of CaO-B2O3-SiO2 （CBS） glass ceramics were investigated by Fourier transform infrared spectroscopy （FTIR）, X-ray diffractometry （XRD） and scanning electron microscopy （SEM）. The results show that the increasing amount of B203 causes the increase of the contents of [BO3], [BO4] and [SiO4], which deduces the increase of CaB204 and a-SiO2 and the decrease of CaSiO3 correspondingly. No new phase is observed throughout the entire experiments. A bulk density of 2.54 g/cm3, a thermal expansion coefficient value of 11.95× 10-6 ℃-1 （20-500℃）, a dielectric constant er value of 6.42 and a dielectric loss tanδ value of 0.000 9 （measured at 9.7 GHz） are obtained for CBS glass ceramics containing 35%-B203 （mass fraction） sintered at 850 ℃ for 15 min.

Methylprednisolone exerts neuroprotective effects by regulating autophagy and apoptosis

Methylprednisolone markedly reduces autophagy and apoptosis after secondary spinal cord injury. Here, we investigated whether pretreatment of cells with methylprednisolone would protect neuron-like cells from subsequent oxidative damage via suppression of autophagy and apoptosis. Cultured N2 a cells were pretreated with 10 μM methylprednisolone for 30 minutes, then exposed to 100 μM H2O2 for 24 hours. Inverted phase contrast microscope images, MTT assay, flow cytometry and western blot results showed that, compared to cells exposed to 100 μM H2O2 alone, cells pretreated with methylprednisolone had a significantly lower percentage of apoptotic cells, maintained a healthy morphology, and showed downregulation of autophagic protein light chain 3B and Beclin-1 protein expression. These findings indicate that methylprednisolone exerted neuroprotective effects against oxidative damage by suppressing autophagy and apoptosis.

Heteroatom tuning in agarose derived carbon aerogel for enhanced potassium ion multiple energy storage

The incorporation of heteroatoms into carbon aerogels(CAs)can lead to structural distortions and changes in active sites due to their smaller size and electronegativity compared to pure carbon.However,the evolution of the electronic structure from single-atom doping to heteroatom codoping in CAs has not yet been thoroughly investigated,and the impact of codoping on potassium ion(K+)storage and diffusion pathways as electrode material remains unclear.In this study,experimental and theoretical simulations were conducted to demonstrate that heteroatom codoping,composed of multiple heteroatoms(O/N/B)with different properties,has the potential to improve the electrical properties and stability of CAs compared to single-atom doping.Electronic states near the Fermi level have revealed that doping with O/N/B generates a greater number of active centers on adjacent carbon atoms than doping with O and O/N atoms.As a result of synergy with enhanced wetting ability(contact angle of 9.26°)derived from amino groups and hierarchical porous structure,ON-CA has the most optimized adsorption capacity(−1.62 eV)and diffusion barrier(0.12 eV)of K^(+).The optimal pathway of K^(+)in ON-CA is along the carbon ring with N or O doping.As K^(+)storage material for supercapacitors and ion batteries,it shows an outstanding specific capacity and capacitance,electrochemical stability,and rate performance.Especially,the assembled symmetrical K^(+)supercapacitor demonstrates an energy density of 51.8 Wh kg^(−1),an ultrahigh power density of 443Wkg^(−1),and outstanding cycling stability(maintaining 83.3%after 10,000 cycles in 1M KPF6 organic electrolyte).This research provides valuable insights into the design of highperformance potassium ion storage materials.

Pattern of disharmony between the heart and kidney: Theoretical basis, identification and treatment

'Harmony between the heart and kidney' refers to the physiological relationship between these two zang organs in Chinese medicine,while 'disharmony between the heart and kidney' (also called disharmony between fire and water) refers to the pathological state.The pattern of disharmony between the heart and kidney is widely observed in patients with insomnia,anxiety disorder and menopausal syndrome,etc..In order to gain a full and systematical understanding of this pattern,from the perspective of ancient Chinese philosophy and zang-fu theory in Chinese medicine,we systematically reviewed and discussed the functions and physiological characteristics of the heart and kidney,the origin and development of theories relating to heart-kidney relationship,the pathogenesis and identification of the pattern,as well as the commonly used classical formulas for its treatment,including Coptis and DonkeyHide Gelatin Decoction (Huánglián (E)jiāo Tāng) and Grand Communication Pill (Jiāotài Wán).Two examples of clinical modifications of these formulas in the treatment of insomnia and menopausal syndrome are provided in this article.It should be noted that in clinical practice,these formulas should be used flexibly,and modified in accordance to the condition of the patient.

Effects of Coagulation and Ozonation Pretreatments on Biochemical Treatment of Fluid Catalytic Cracking Wastewater

Fluid catalytic cracking (FCC) salty wastewaters, containing quaternary ammonium compounds (QACs), are very difficult to treat by biochemical process. Anoxic/oxic (A/O) biochemical system, based on nitrification and denitrification reactions, was used to assess their possible biodegradation. Because of the negative effects of high salt concentration (3%), heavy metals and toxic organic matter on microorganisms’ activities, some techniques consisting of dilution, coagulation and flocculation, and ozonation pretreatments, were gradually tested to evaluate chemical oxygen demand (COD), ammonia-nitrogen (ammonia-N) and total nitrogen (TN) removal rates. In this process of FCC wastewater, starting with university-domesticated sludge, the ammonia-N and TN removal rates were worst. However, when using domesticated SBR’s sludge and operating with five-fold daily diluted influent (thus reducing salt concentration), the ammonia-N removal reached about 57% while the TN removal rate was less than 37% meaning an amelioration of the nitrification process. However, by reducing the dilution factors, these results were inflected after some days of operation, with ammonia-N removal decreasing and TN barely removed meaning a poor nitrification. Even by reducing heavy metals concentration with coagulation/flocculation process, the results never changed. Thereafter, by using ozonation pre-treatment to degrade the detected organic matter of di-tert-butylphenol and certain isoparaffins, COD, ammonia-N and TN removal rates reached 92%, 62% and 61%, respectively. These results showed that the activities of the microorganisms were increased, thus indicating a net denitrification and nitrification reactions improvement.

Effects of spring fire and slope on the aboveground biomass, and organic C and N dynamics in a semi-arid grassland of northern China

The aboveground primary production is a major source of carbon(C) and nitrogen(N) pool and plays an important role in regulating the response of ecosystem and nutrient cycling to natural and anthropogenic disturbances. To explore the mechanisms underlying the effect of spring fire and topography on the aboveground biomass(AGB) and the soil C and N pool, we conducted a field experiment between April 2014 and August 2016 in a semi-arid grassland of northern China to examine the effects of slope and spring fire, and their potential interactions on the AGB and organic C and total N contents in different plant functional groups(C_3 grasses, C_4 grasses, forbs, Artemisia frigida plants, total grasses and total plants).The dynamics of AGB and the contents of organic C and N in the plants were examined in the burned and unburned plots on different slope positions(upper and lower). There were differences in the total AGB of all plants between the two slope positions. The AGB of grasses was higher on the lower slope than on the upper slope in July. On the lower slope, spring fire marginally or significantly increased the AGB of C_3 grasses, forbs, total grasses and total plants in June and August, but decreased the AGB of C_4 grasses and A.frigida plants from June to August. On the upper slope, however, spring fire significantly increased the AGB of forbs in June, the AGB of C_3 grasses and total grasses in July, and the AGB of forbs and C_4 grasses in August. Spring fire exhibited no significant effect on the total AGB of all plants on the lower and upper slopes in 2014 and 2015. In 2016, the total AGB in the burned plots showed a decreasing trend after fire burning compared with the unburned plots. The different plant functional groups had different responses to slope positions in terms of organic C and N contents in the plants. The lower and upper slopes differed with respect to the organic C and N contents of C_3 grasses, C_4 grasses, total grasses, forbs, A. frigida plants and total plants in different growing months. Slope position and spring fire significantly interacted to affect the AGB and organic C and N contents of C_4 grasses and A. frigida plants. We observed the AGB and organic C and N contents in the plants in a temporal synchronized pattern. Spring fire affected the functional AGB on different slope positions, likely by altering the organic C and N contents and, therefore,it is an important process for C and N cycling in the semi-arid natural grasslands. The findings of this study would facilitate the simulation of ecosystem C and N cycling in the semi-arid grasslands in northern China.

Aspects on the Mechanism of the 1-Phenyl-1<i>H</i>-pyrazolo[3,4-<i>b</i>]quinoxaline Formation

Condensation of D-glucose, o-phenylenediamine and N,N-benzylphenylhydrazine hydrochloride (NNBPHH) in a one-pot reaction, or condensation of 2-(D-arabino-tetritol-1-yl) quinoxaline and NNBPHH, gave 3-(D-erythro-glycerol-1- yl)-1-phenyl-1H-pyrazolo[3,4-b]quinoxaline. The structure of the latter was determined by 1H NMR spectroscopy and by synthesis using phenylhydrazine hydrochloride instead of NNBPHH. Condensation of D-glucose and 4,5-dichloro-o-phenylenediamine gave 6,7-dichloro-2-(D-arabino-tetritol-1-yl)quinoxaline, which upon condensation with NNBPHH gave the corresponding 6,7-dichloro-3-(D-erythro-glycerol-1-yl)-1-phenyl-1H-pyrazolo[3,4-b]quinoxaline. The structure and mechanism of formation of these compounds are discussed.

Correlations between Mineral Nitrogen Contents and Vertical Distribution of N20 Emission Potentials in Tropical Peat Soils Transformed into Oil Palm Plantations in Sarawak, Malaysia

Tropical peat swamp forest beds that have been reclaimed for agricultural use are generally an active source of nitrous oxide （N2O） efflux, however, the mechanism by which reclaimed tropical peat soils promote the emergence of N2O emitters in soil microbial communities remains unclear. The purpose of this study was to reveal the vertical distribution of N2O emission potential and its correlation with mineral nitrogen contents in reclaimed soils. Using a culture-based N2O emission assay, the N2O emission potentials of soil at various depths （0-450 cm） were investigated in two oil palm plantations in Sarawak, Malaysia, which had elapsed times of two years （E2Y） and 10 years （El 0Y） after deforestation, respectively. On the basis of the relationship between the vertical profiles of N2O emission potentials and the contents of mineralized nitrogen in the peat soils at various depths, the impact of land management on soil microbial communities was discussed. The peat soil at plantation site E2Y showed a trend of high N2O production in deep layers （200-400 cm）, whereas the older plantation site E10Y showed considerably more active N2O emission in shallow soil （10-50 cm）. N2O emission potentials among the soil microbial communities at different soil depths at the E10Y site showed positive correlations with NO3- and NH4＋ contents, whereas, soils obtained from the E2Y site had N2O emission potentials that were inversely proportional to the contents of NO3-. This contrasting vertical correlation between N2O-emitting potentials and mineralized nitrogen contents in bulk soils suggests that active N2O emission in deep soil at the E2Y site has maintained the original carbon-nitrogen （C/N） ratio of the peat soil, whereas at EIOY, such a regulatory system has been lost due to advanced soil degradation, leading to dynamic changes in the nitrogen cycle in shallow soil.

Effects of Mowing Heights on N₂O Emission from Temperate Grasslands in Inner Mongolia, Northern China

Grazing and mowing are two common practices for grassland management. Mowing is now recommended as an alternative to the traditional grazing for grassland conservation in Inner Mongolia, northern China. Many studies have revealed that mowing may alter ecosystem properties in various ways. However, little attention has been paid to the effect of mowing on trace gas emissions, especially on N2O flux. We conducted an experiment to investigate the effects of mowing on N2O fluxes from the semiarid grassland in Inner Mongolia. The mowing experiment, which started in 2003, comprised four mowing intensity treatments, i.e. mowing heights at 2 cm, 5 cm, 10 cm and 15 cm above the soil surface, respectively, and a control (non-mowing), with five replicates. Gas fluxes were measured through a closed static chamber technique during the growing seasons (usually from May to September, depending on local climate at the time) of 2008 and 2009, respectively. Our results showed that mowing decreased N2O emissions, above-ground biomass and total litter production. N2O emissions were greater in May and June than in other sampling periods, regardless of treatments (P 2O fluxes were mainly driven by variations in soil moisture, except in July and August. In July and August, above-ground plant biomass and soil total nitrogen became the major drivers of N2O fluxes under the soil temperatures between 16 ° C and 18 ° C. Though there were some uncertainties due to the low frequency of N2O flux measurement, our study mainly indicated that 5 cm mowing height might decrease N2O emissions in grasslands during the growing season, and soil properties affected the magnitude of the reduction.

Multiple-dimensioned defect engineering for graphite felt electrode of vanadium redox flow battery

The scarcity of wettability,insufficient active sites,and low surface area of graphite felt(GF)have long been suppressing the performance of vanadium redox flow batteries(VRFBs).Herein,an ultra-homogeneous multipledimensioned defect,including nano-scale etching and atomic-scale N,O codoping,was used to modify GF by the molten salt system.NH_(4)Cl and KClO_(3) were added simultaneously to the system to obtain porous N/O co-doped electrode(GF/ON),where KClO_(3) was used to ultra-homogeneously etch,and O-functionalize electrode,and NH4Cl was used as N dopant,respectively.GF/ON presents better electrochemical catalysis for VO_(2)+/VO_(2)+ and V3+/V2+ reactions than only O-functionalized electrodes(GF/O)and GF.The enhanced electrochemical properties are attributed to an increase in active sites,surface area,and wettability,as well as the synergistic effect of N and O,which is also supported by the density functional theory calculations.Further,the cell using GF/ON shows higher discharge capacity,energy efficiency,and stability for cycling performance than the pristine cell at 140 mA cm^(−2) for 200 cycles.Moreover,the energy efficiency of the modified cell is increased by 9.7% from 55.2% for the pristine cell at 260 mA cm^(−2).Such an ultra-homogeneous etching with N and O co-doping through“boiling”molten salt medium provides an effective and practical application potential way to prepare superior electrodes for VRFB.

Impacts of central-Pacific El Niño and physical drivers on eastern Pacific bigeye tuna

Bigeye tuna Thunnus obesus is an important migratory species that forages deeply,and El Niño events highly influence its distribution in the eastern Pacific Ocean.While sea surface temperature is widely recognized as the main factor affecting bigeye tuna(BET)distribution during El Niño events,the roles of different types of El Niño and subsurface oceanic signals,such as ocean heat content and mixed layer depth,remain unclear.We conducted A spatial-temporal analysis to investigate the relationship among BET distribution,El Niño events,and the underlying oceanic signals to address this knowledge gap.We used monthly purse seine fisheries data of BET in the eastern tropical Pacific Ocean(ETPO)from 1994 to 2012 and extracted the central-Pacific El Niño(CPEN)indices based on Niño 3 and Niño 4indexes.Furthermore,we employed Explainable Artificial Intelligence(XAI)models to identify the main patterns and feature importance of the six environmental variables and used information flow analysis to determine the causality between the selected factors and BET distribution.Finally,we analyzed Argo datasets to calculate the vertical,horizontal,and zonal mean temperature differences during CPEN and normal years to clarify the oceanic thermodynamic structure differences between the two types of years.Our findings reveal that BET distribution during the CPEN years is mainly driven by advection feedback of subsurface warmer thermal signals and vertically warmer habitats in the CPEN domain area,especially in high-yield fishing areas.The high frequency of CPEN events will likely lead to the westward shift of fisheries centers.

Effect of rich R-TiO2 on the rate and cycle properties of Li4Ti5O12 as anode for lithium ion batteries

Li4Ti5012 (LTO) with rich R-TiO2 (17.06, 23.69, and 34.42 wt%), namely, R-TiO2@Li4Ti5O12 composites, were synthesized using the hydrothermal method and tetrabutyl titanate (TBT) as the precursor. Rietveld refinement of X-ray diffraction (XRD) results show that the proportion of Li occupying 16d sites is extraordinary low and the lattice constants of LTO and R-TiO2 change with the ritanium dioxide content. EIS measurements showed that with in creasing R-TiO2 content, both its charge transfer impedance (Rct) and lithium ion diffusion coefficient (DLi) decreased. The changes of Rct and DLi caused by the increase of titanium dioxide content have synergic-antagonistic effects on the rate and cycle properties of Li4Ti5012. The rate performance is positively related to DLi, while the cycle property is negatively correlated with Rct, indicati ng that the rate performs nee is mainly related to DLi, while Rct more significantly affects the cycle performance. LTO-RT-17.06% exhibited excellent rate properties, especially under a high current density (5.0 C, 132.5 mAh/g) and LTO-RT-34.42% showed superior long-term cycle performance (0.012% capacity loss per cycle) compared to that of LTO-RT-17.06% and LTO-RT-23.69%.

Microstructure and mechanical properties of Ti(C, N)-based cermets with different molybdenum contents

The microstructure and mechanical properties of Ti(C, N)-based cermets with different content Mo were studied. Different Mo contents were added into Ti(C, N)-based cermets. Effect of sintering temperature on mechanical properties of the cermets was also investigated. Specimens were fabricated by conventional powder metallurgy techniques and vacuum sintered at different temperatures. The microstructure and the fracture morphology were investigated using scanning electron microscope. Transverse strength and hardness were measured. The results show that the microstructure is uniform and the thickness of rim phase is moderate when the content of Mo is 8%. The mechanical properties are the best when the content of Mo is 8% and the sintering temperature is 1450℃.

CuO掺杂C_(3)N对C_(5)F_(10)O分解组分吸附性能的第一性原理研究

全氟五碳酮(C_(5)F_(10)O)作为可替代SF_(6)的新型环保绝缘气体已被投入到实际应用中.当绝缘设备内部发生局部放电等故障时,C_(5)F_(10)O会分解产生弱绝缘性的CF_(4)、C_(2)F_(6)以及剧毒的CF_(2)O、HF等有害组分,为保证绝缘设备的安全运行,需有选择地通过吸附去除这些分解组分.新型类石墨烯C_(3)N材料在气体吸附领域具有良好的应用前景,文中基于第一性原理计算了CuO分子掺杂C_(3)N对主要分解组分CF_(4)、C_(2)F_(6)及剧毒产物CF_(2)O、HF的吸附过程,计算并分析了各分解组分吸附时的吸附能、态密度、电荷转移量、差分电荷密度以及不同环境温度下的恢复时间.结果表明,CuO-C_(3)N对HF表现出良好的吸附性,CF_(2)O次之,但其无法吸附CF_(4)与C_(2)F_(6),因此CuO-C_(3)N可以作为一种高性能的气体吸附剂对C_(5)F_(10)O绝缘设备内的剧毒分解组分HF进行吸附去除.

Effect of Substitution Degree and the Calcination Temperature on the N₂O Decomposition over Zinc Cobaltite Catalysts

In this paper, a series of zinc cobaltite catalysts with the general formula Znx-Co1-xCo2O4 (x = 0.25, 0.50, 0.75 and 1.0) has been prepared using the co-precipitation method. Thermal analyzes (TGA and DTA) were used to follow up the thermal events accompanying the heat treatment of the parent mixture. Based on these results, the various parent mixtures were calcined at 500℃. The obtained solid catalysts were characterized by using XRD, FT-IR and N2-adsorption. The catalytic decomposition of N2O to N2 and O2 was carried out on the zinc-cobaltite catalysts. It was found that partial replacement of Co2+ by Zn2+ in Co3O4 spinel oxide led to a significant improvement in their N2O decomposition activity. Moreover, the catalytic activity was found to be depended on the calcination temperature utilized.

Effect of Light Quality and Intensity on N_2O and NO_X(NO, NO_2)Emissions from Rice Phyllosphere and Roots at Tillering Stage in a Liquid Culture Medium System

[Objective] N2Oand NOX（NO, NO2） are important nitrogen oxides gases（NOGs） in paddy fields, and rice plants play important roles in NOG emissions in paddy fields. However, the source of NOG emissions from rice phyllosphere and roots and their relationship to light quality and intensity still remain unclear. In this study, the relationship between light quality, intensity and N2 O, NOX（NO, NO2） emissions from rice phyllosphere and roots at tillering stage was investigated to clarify the contribution of rice plants to N2Oand NOX（NO, NO2） emissions and analyze the mechanism of light control, aiming at providing a scientific basis for revealing how light-control technology affects NOG emissions from rice at tillering stage in paddy fields. [Method] In this study, nitrogen content was controlled by a hydroponic system. A small electric incubator was used for light control. A simultaneous determination was designed to investigate the effect of different weak light qualities（yellow, green, white, red and blue lights） and intensities（dark, 0 lx; very weak, 2 000lx; weak, 4 000 lx; moderate, 6 000 lx; strong, 8 000 lx） on N2Oand NOXemissions from rice phyllosphere and roots at tillering stage in a liquid culture medium system. N2Oconcentration in air samples was determined by gas chromatography within 12 h, and NOX（NO, NO2） concentration was analyzed using 42 i NO- NO2-NOXgas analyzer. [Result] The results showed that：（1） Under a constant nitrogen condition（NH4NO3-N, 90 mg/L） when rice seedlings were treated with moderate（6 000lx） and strong（8 000 lx） light, the average emission rate of N2Oand NO from rice phyllosphere at tillering stage was 27.08, 32.33 μg/（pot·h） and 0.114, 0.057 μg/（pot·h）,respectively, accounting for 57.38%, 58.65% and 9.65%, 4.52% of the total release of N2Oand NO from the whole rice plant, respectively. It implicated that rice phyllosphere is an important source of N2Oemission at tillering stage in paddy fields.（2）When rice seedlings were treated with yellow, green, white, red and blue LED lights under a constant light intensity（1 600 lx）, the average emission rate of N2Ofrom rice phyllosphere was 6.83, 9.40, 9.73, 2.82 and 4.08 μg/（pot·h）, respectively. Compared with green and yellow LED lights, N2Oemission from rice phyllosphere and roots at tillering stage was inhibited markedly by red（3 000 lx） and blue（2 500 lx）LED lights（P0.01）. In addition, NO emission from rice phyllosphere was enhanced significantly by white and red LED lights, while NO emissions from rice phyllosphere and roots were inhibited by blue light synchronously. Nevertheless, no evident NO2 emission from rice phyllosphere and roots was detected under the same condition.（3） Within the range of 0-8 000 lx, NO and N2Oemissions from rice roots and N2Oemission from rice phyllosphere increased with the enhancement of light intensity. In contrast, NO emission from rice phyllosphere was inhibited remarkably by moderate（6 000 lx） and strong（8 000 lx） light（P〈 0.01）. [Conclusion] Rice seedlings mainly exhibited net emissions of NO2 from the phyllosphere and roots.N2Oand NOX（NO, NO2） emissions from rice phyllosphere and roots at tillering stage could be inhibited by adjusting the composition of visible light（synchronously increasing the proportions of red and blue lights） and appropriately controlling daytime light intensity.

Nitrogen cycling and environmental impacts in upland agricultural soils in North China： A review

The upland agricultural soils in North China are distributed north of a line between the Kunlun Mountains, the Qinling Mountains and the Huaihe River. They occur in arid, semi-arid and semi-humid regions and crop production often depends on rain-fed or irrigation to supplement rainfall. This paper summarizes the characteristics of gross nitrogen（N） transformation, the fate of N fertilizer and soil N as well as the N loss pathway, and makes suggestions for proper N management in the region. The soils of the region are characterized by strong N mineralization and nitrification, and weak immobilization and denitrification ability, which lead to the production and accumulation of nitrate in the soil profile. Large amounts of accumulated nitrate have been observed in the vadose-zone in soils due to excess N fertilization in the past three decades, and this nitrate is subject to occasional leaching which leads to groundwater nitrate contamination. Under farmer＇s conventional high N fertilization practice in the winter wheat-summer maize rotation system（N application rate was approximately 600 kg ha–1 yr–1）, crop N uptake, soil residual N, NH_3 volatilization, NO_3~– leaching, and denitrification loss accounted for around 27, 30, 23, 18 and 2% of the applied fertilizer N, respectively. NH_3 volatilization and NO_3~– leaching were the most important N loss pathways while soil residual N was an important fate of N fertilizer for replenishing soil N depletion from crop production. The upland agricultural soils in North China are a large source of N_2O and total emissions in this region make up a large proportion（approximately 54%） of Chinese cropland N_2O emissions. The “non-coupled strong ammonia oxidation” process is an important mechanism of N_2O production. Slowing down ammonia oxidation after ammonium-N fertilizer or urea application and avoiding transient high soil NH4＋ concentrations are key measures for reducing N_2O emissions in this region. Further N management should aim to minimize N losses from crop and livestock production, and increase the recycling of manure and straw back to cropland. We also recommend adoption of the 4 R（Right soure, Right rate, Right time, Right place） fertilization techniques to realize proper N fertilizer management, and improving application methods or modifying fertilizer types to reduce NH_3 volatilization, improving water management to reduce NO_3~– leaching, and controlling the strong ammonia oxidation process to abate N_2O emission. Future research should focus on the study of the trade-off effects among different N loss pathways under different N application methods or fertilizer products.

Emission Characteristics of Soil Nitrous Oxide from Typical Greenhouse Vegetable Fields in North China

To make clear the emission characteristics of soil N20 from typical green- house vegetable fields in North China, an experiment was conducted in greenhouse tomato field in Shouguang city, Shandong province, China＇s ＂Home of Vegetables＂. The N2O fluxes were observed in four experimental treatments, as follows： none N fertilizer （CK）, single organic fertilizer （OM）, conventional fertilization （FP） and opti- mized and reduced nitrogen fertilization （OPT）, by a close chamber-gas chromato- graph method. The effects of different fertilization treatments on N2O emission and tomato yield were analyzed. The results showed that following the fertilization and ir- rigation, the pulsed emissions of N2O were measured. The N2O emission peak ap- peared after basal fertilizer application and irrigation and could be maintained for about 20 days. While the N2O emission peak caused by topdressing was smaller and last only 3-5 days. The statistical analysis showed that the N2O fluxes were affected by air temperature, soil temperature and WFPS at soil depth of 3 cm. The total contents of soil N2O fluxes had significant differences among experimental groups. The total content orderly was FP of 14. 77 kg/hm^2, OPT of 9. 73 kg/hm^2, OM of 6.84 kg/hm^2 and CK of 2.37 kg/hm^2. The N~：~ emission coefficient ranged from 0.83%-1.10%,which was close to or more than the recommended value （1.0%） by IPCC. Compared with the FP treatment, the tomato yield in OPT treatment, whose application rate of chemical N fertilizer decreased by about 60%, increased by 2.2%. Under the current management measures, the reasonable reduction on ap- plicaUon rate of organic manure and chemical nitrogen fertilizer could effectively re- duce the N=O emissions in greenhouse vegetable fields.