Removal of Fulvic Acids from Aqueous Solutions via Surfactant Modified Zeolite

A surfactant modified zeolite（ SMZ）, i. e. , a zeolite modified by using hexadecyl trimethyl ammonium bromide （HDTMA） was used to remove fulvic acids（FA） from aqueous solution. The effects of the relevant parameters, such as the loading level of HDTMA, the contact time, the initial FA concentration, the pH, and the types of the metal carious and organics were examined. The results show that SMZ with an HDTMA loading-level of 120% of the external cation exchange capacity（ECEC） of zeolite exhibits the best performance. Although the removal of fulvic acids by SMZ occurs rapidly within the first 30 min of the contact time, a contact time of at least 4 h is required to attain the adsorption equilibrium. The removal capacity of FA by SMZ decreases with the increase of the initial FA concentration. The pH has an effect on the FA removal efficiency because it can influence the characteristics of the FA molecules. The removal of FA is considerably enhanced by Ca^2＋ or Mg^2＋ ions and is adversely affected by phenol or pentachlorophenol（PCP）. Under the optimum conditions, 98% of FA could be removed by SMZ. Furthermore, the desorption of FA and the regeneration of SMZ were studied. The results show that a 30% ethanol solution is sufficient for the regeneration of SMZ.

富里酸(FA)对微囊藻毒素-LR(MC-LR)的光降解作用及环境影响因素分析

为研究自然水环境中溶解性有机质(DOM)对微囊藻毒素-LR(MC-LR)的光降解作用,选择DOM的主要光敏活性组分富里酸(FA)作为光敏剂,在模拟太阳光照射下,对比了不同质量浓度FA(2.5、5.0、7.5、10.0 mg/L)溶液中MC-LR的光降解规律和光降解产物,并探究了不同pH、光照度对FA光降解MC-LR的影响。结果表明:MC-LR能在去离子水中发生直接光降解反应,不同质量浓度的FA对MC-LR的光降解均有促进作用,其中,7.5 mg/L FA对MC-LR的光降解作用最强,180 min时降解率达52.65%;FA对MC-LR的光降解过程符合二级反应动力学方程,其光降解产物与在去离子水中直接光降解的产物相同;不同pH和光照度下,FA对MC-LR的光降解作用依次为pH 6>pH 7>pH 8>pH 9,39.8μmol/(s·m^(2))>56.9μmol/(s·m^(2))>22.8μmol/(s·m^(2))。研究表明,pH和光照度均会影响FA对MC-LR的光降解作用,其中,pH为6、光照度为39.8μmol/(s·m^(2))时,FA对MC-LR光降解作用最强。

Effects of Three Humic Acid Foliar Fertilizers on Quality and Photosynthetic Characteristics of Hawthorn

[Objectives]To investigate the effects of three foliar fertilizers on photosynthetic characteristics,fruit quality and yield of hawthorn.[Methods]Taking hawthorn foliar fertilization as the reference,the photosynthetic rate,transpiration rate,intercellular CO 2 concentration,stomatal conductance and single fruit weight of hawthorn leaves were measured under different concentrations of foliar fertilizer.[Results]The results showed that the photosynthetic rate,transpiration rate and stomatal conductance of hawthorn leaves increased significantly,while the intercellular CO 2 concentration decreased.Specifically,the fish protein peptide foliar fertilizer performed best,with net photosynthetic rate and transpiration rate increased by 57.22%and 57.51%,respectively.All the three foliar fertilizers significantly reduced the intercellular CO 2 concentration.In addition,fertilization significantly increased the single fruit weight of hawthorn,and the effect of fermented fulvic acid foliar fertilizer was the most significant,with the highest growth rate of 68.49%.[Conclusions]Spraying foliar fertilizer significantly increased the content of Vc,titratable acid,anthocyanin and soluble solids of hawthorn fruit,among which fermented fulvic acid foliar fertilizer had the optimal effect.

益母草碱调节Fas/FasL信号通路对乳腺癌细胞恶性生物行为的影响

目的探讨益母草碱(Leonurine,Leo)对乳腺癌细胞的增殖、迁移、凋亡、细胞周期进展以及上皮间质转化的影响及作用机制。方法体外培养4T1乳腺癌细胞,将细胞分为对照组(Control组)、益母草碱低、中、高浓度组(Leo-L组、Leo-M组、Leo-H组)、益母草碱高浓度+转染短发夹RNA慢病毒阴性对照组(Leo-H+sh-NC组),益母草碱高浓度+转染Fas短发夹RNA慢病毒组(Leo-H+sh-Fas组)。使用不同浓度的益母草碱(10~160 mmol/L)处理细胞,CCK-8法检测细胞的存活率,筛选最佳实验浓度;通过Transwell小室法评价细胞的迁移能力;流式细胞术检测细胞凋亡率及细胞周期进展;Western blot检测N-cadherin、Vimentin、Fas、FasL表达,建立荷瘤小鼠模型评价益母草碱对乳腺癌移植瘤生长的影响。结果使用浓度为10~160 mmol/L的益母草碱处理细胞12 h,4T1细胞存活率显著降低(P<0.05),半数抑制浓度(IC50值)为(53.61±1.729)mmol/L,选择10、20、30 mmol/L为后续实验浓度;与Control组相比,Leo-L组、Leo-M组、Leo-H组4T1细胞的增殖活力、迁移率、G2/M期细胞比例及S期细胞比例、N-cadherin、Vimentin表达显著降低(P<0.05),细胞凋亡率、G0/G1期细胞比例、Fas、FasL表达显著升高(P<0.05);与Leo-H+sh-NC组相比,Leo-H+sh-Fas组4T1细胞的增殖活力、迁移率、G2/M期细胞比例及S期细胞比例、N-cadherin、Vimentin表达显著升高(P<0.05),细胞凋亡率、G0/G1期细胞比例、Fas、FasL表达显著降低(P<0.05);益母草碱可以抑制乳腺癌移植瘤的生长(P<0.05)。结论益母草碱可以抑制乳腺癌细胞恶性生物行为,其作用机制可能与激活Fas/FasL信号通路有关。

Effects of fulvic acid and humic acid on aluminum speciation in drinking water

This article focused on the influences of fulvic acid and humic acid on aluminum speciation in drinking water. Factors including the concentration of residual chlorine and pH value had been concerned. Aluminum species investigated in the experiments included inorganic mononuclear, organic mononuclear, mononuclear, polymer, soluble, and suspended forms. It was found that the effects of fulvic acid and humic acid on aluminum speciation depended mainly on their molecular weight. Fulvic acid with molecular weight less than 5000 Dalton had little influence on aluminum speciation; while fulvic acid with molecular weight larger than 5000 Dalton and humic acid would increase the concentration of soluble aluminum significantly even at concentration below 0.5 mg/L （calculated as TOC）. Aluminum species, in the present of fulvic acid with molecular weight larger than 5000 Dalton and humic acid, were more stable than that in the present of fluvic acid with molecular mass less than 5000 Dalton, and varied little with reaction time. Within pH range 6.5-7.5, soluble aluminum increased notably in water with organic matter. As the concentration of residual chlorine increased, the effects of fulvic acid and humic acid became weak. The reactions between humic acid, fulvic acid with large molecular weight, and aluminum were considered to be a multi-dentate coordination process. With the consideration of aluminum bioavailability, reducing the concentration of fulvic acid and humic acid and keeping the pH value among 6.5-7.5 were recommended during drinking water treatment.

COMPARATIVE FATTY ACID COMPOSITION OF FOUR SARGASSUM SPECIES(FUCALES,PHAEOPHYTA)

Fatty acid composition of four Sargassum species from Qingdao and Shidao,Shandong Provincewas investigated.16:0（palmitic acid）was the major saturated fatty acid.C18 and C20were the mainpolyunsaturated fatty acids（PUFAs）.Arachidonic acid and eicosapentaenoic acid predominated amongpolyenoic acids in all the algal species examined.except for Sargassum sp.which had low concentrationof eicosapentaenoic acid.

Adsorption characterizations of fulvic acid fractions onto kaolinite

Fulvic acids extracted from a typical rice-production region near Taihu Lake of China were fractionated into three fractions including F4.8, F7.0 and F11.0 （eluted by pH 4.8 buffer, pH 7.0 buffer and pH 11.0 buffer, respectively）. Sorption of fulvic acid （FA） fractions onto kaolinite was studied by batch adsorption experiments, and characterizations of kaolinite before and after adsorption were investigated using scanning electron microscopy （SEM）. Adsorption isotherms of kaolinite for three FA fractions fit well with the Langrnuir adsorption model. The adsorption density of the three fractions was positively correlated with the ratio of the amount of the alkyl carbon to that of carboxyl and carbonyl carbon in FA fractions and followed an order of F11.0 〉 F7.0 〉 F4.8. Hydrophobic interaction was one of the control mechanisms for the sorption of FA fraction onto kaolinite. SEM images confirmed that compared to blank kaolinite samples, kaolinite samples coated by a FA fraction displayed an opener and more dispersed conformation resulting from the disruption of the floc structure in complex. Dispersion of kaolinite after adsorption was due to the repulsion between negatively charged FA-coated particles, which is closely related to the amount of FA fractions absorbed on kaolinite.

The Promotion Effect of Low-Molecular Hydroxyl Compounds on the Nano-Photoelectrocatalytic Degradation of Fulvic Acid and Mechanism

A significant promotion effect of low-molecular hydroxyl compounds(LMHCs) was found in the nano-photoelectrocatalytic(NPEC) degradation of fulvic acid(FA),which is a typical kind of humic acid existing widely in natural water bodies,and its influence mechanism was proposed.A TiO_2 nanotube arrays(TNAs) material is served as the photoanode.Methanol,ethanediol,and glycerol were chosen as the representative of LMHCs in this study.The adsorption performance of organics on the surface of TNAs was investigated by using the instantaneous photocurrent value.The adsorption constants of FA,methanol,ethanediol,and glycerol were 43.44,19.32,7.00,and 1.30,respectively,which indicates that FA has the strongest adsorption property.The degradation performance of these organics and their mixture were observed in a thin-layer reactor.It shows that FA could hardly achieve exhausted mineralization alone,while LMHCs could be easily oxidized completely in the same condition.The degradation degree of FA,which is added LMHCs,improves significantly and the best promotion effect is achieved by glycerol.The promotion effect of LMHCs in the degradation of FA could be contributed to the formation of a tremendous amount of hydroxyl radicals in the NPEC process.The hydroxyl radicals could facilitate the complete degradation of both FA and its intermediate products.Among the chosen LMHCs,glycerol molecule which has three hydroxyls could generate the most hydroxyl radicals and contribute the best effective promotion.This work provides a new way to promote the NPEC degradation of FA and a direction to remove humus from polluted water.

The Effects of Dietary Fatty Acid Pattern on Layer's Performance and Egg Quality

The feeding trial was conducted to determine the effects of flaxseed on layer＇s performance and egg quality, and the effects of the dietary ratio of ω-6 fatty acid to ω-3 fatty acid on fatty acid deposition in yolk using flaxseed as resource of ω-3 fatty acid and sunflower seed as resource of ω-6 fatty acid. 192 20-wk-old Newroman commercial hens were randomly divided into 4 treatment groups with 6 replicates containing 8 birds. The rations corresponding with the four treatments were formulated with 4% flaxseed ＋ 9% sunflower seed, 8% flaxseed ＋ 18% sunflower seed, 15% flaxseed, and soybean meal, respectively. Sunflower seed was unshelled and flaxseed was whole. Ratios of ω-6 fatty acid to ω-3 fatty acid in 4 dietary treatments were 5.67, 5.21, 1.07, and 11.83, respectively. It can be concluded that long-term feeding 15% flaxseed had no significant （P〉 0.05） influence on egg production, egg weight, eggshell quality, yolk weight, and percentage of yolk weight. Dietary ratio of ω-6 fatty acid to ω-3 fatty acid had impact on the 0-3 fatty acid levels in yolk, nevertheless yolk fatty acid profiles were different from those of dietary fatty acid compositions.

Fulvic acid degradation using nanoparticle TiO_2 in a submerged membrane photocatalysis reactor

The degradation of fulvic acid（FA） by nanoparticle TiO2 in a submerged membrane photocatalysis（SMPC） reactor was studied. In this reactor, photocatalytic oxidation and membrane separation co-occured. The continuous air supplier provided O2 for the photocatalytical reaction and mixed the solution through an airflow controller. The particle TiO2 could automatically settle due to gravity without particle agglomeration so it could be easily separated by microfiltration（MF） membrane. It was efficient to maintain high flux of membranes. The effects of operational parameters on the photocatalytic oxidation rate of FA were investigated. Results indicated that photocatalyst at 0.5 g/L and airflow at 0.06 m^3/h were the optimum condition for the removal of fulvic acid, the removal efficiency was higher in acid media than that in alkaline media. The effects of different filtration duration on permeate flux rate of MF with P25 powder and with nanoparticle TiO2 were compared. Experimental results indicated that the permeate flux rate of MF was improved and the membrane fouling phenomenon was reduced with the addition of nanoparticle TiO2 catalyst compared with conventional P25 powder. Therefore, this submerged membrane photocatalysis reactor can faciliate potential application of photocatalytic oxidation process in drinking water treatment.

Effect of Retinoic Acid on Apoptosis and Expression of Fas Proteins in Mouse Blastocysts Cultured In Vitro

Mouse blastocysts were exposed to doses of 0, 1 and 10 μmol/L retinoic acid （RA） for 24 h and the cytotoxic effect of RA on the mouse blastocysts in vitro was observed. FITC-labeled terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL-FITC） assay was employed to stain apoptotic cells and immunohistochemical S-P staining method was used to detect the expression of Fas protein in mouse blastocysts in vitro. The results showed that RA could induce apoptosis and increase the expression of Fas proteins of trophectoderm （TE） and inner cell mass （ICM） cells in blastocysts. Compared with the findings for the control blastocysts, exposure to RA （10 μmol/L） resulted in a more significant apoptosis and higher expression level of Fas proteins （P〈0.01）. It was concluded that RA could induce apoptosis, which may result in a significant reduction in the average number of total cells and the trophectoderm/inner cell mass in blastocysts and an increased expression of Fas protein, suggesting that RA had a cytotoxic effect on the growth and development of early embryos in mice.

Compositional and Structural Difference of Fulvic Acid from Black Soil Applied with Different Organic Materials: Assessment After Three Years

Knowledge of different effects of various organic materials on soil humic substance is important for both environmental safety and sustainable agriculture.A pot experiment was conducted at Jilin Agricultural University,Jilin Province in northeast China to discover the influence of herb residue,animal excrement,woody residue,animal remnant on fulvic acid（FA） composition and structure using differential thermal analysis-thermogravimetric（DTA-TG）,fourier transform infrared spectroscopy（FTIR） and elemental analysis.DTA-TG showed the range of peak temperature in the first exothermic reaction increased following the trend： CK〉herb residue〉animal excrement〉woody residue=animal remnant,and the most weight loss was observed in animal excrement.Moreover,the second exothermic reaction of CK-and animal excrement-FA was presented as double peaks,the order of weight loss in that area was animal remnant〉CK〉woody residue〉animal excrement〉herb residue.According to FTIR,herb residue displayed higher adsorption intensity at 2 950,1 420,1 240 and 1 030 cm-1,animal excrement was in reverse.At the same time,herb residue-and animal excrement-FA had an absorption peak at 1 720 cm-1,while other organic materials didn＇t have this peak.As elemental analysis showed,FA isolated from various treatments was significantly distinct.It was clearly shown from our results that FA composition and structure in amended soils may be affected in different ways and at various extents on dependence of the nature and origin of amendment.

Increased fatty acid synthase as a potential therapeutic target in multiple myeloma

Objective:To determine fatty acid synthase(FAS)expression in human multiple myeloma and verify its potential as a therapeutic target in multiple myeloma.Methods:FAS expression was determined by immunohistochemistry,re- verse-transcription polymerase chain reaction(RT-PCR)and immunoblot analysis in bone marrow samples obtained from 27 patients with multiple myeloma(MM patients)and peripheral blood mononuclear cells(PBMCs)obtained from 12 healthy donors. In parallel,additional analyses were performed on 2 human multiple myeloma cell lines,U266 and RPMI8226.U266 cells were treated with cerulenin at various concentrations(5 to 320μg/ml)for 24 h,and metabolic activity was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assays.Apoptosis was evaluated by dual Annexin V/PI (propidium iodide)labeling and flow cytometry(FCM)in U266 cells treated with 20μg/ml cerulenin for 12 h or 24 h.Results:By immunohistochemistry,we found that 19 of 27 bone marrow samples obtained from MM patients expressed significantly high levels of FAS.Similarly,by RT-PCR,22 of 27 bone marrow samples obtained from MM patients,U266 and RPMI8226 showed FAS expression,whereas PBMC samples from 12 healthy donors did not express detectable level of FAS.FAS protein expression was confirmed by immunoblot analysis in 16 of 27 bone marrow samples obtained from MM patients,U266 and RPMI8226 cell lines,and no FAS protein expression was detected in PBMC samples from 12 healthy donors.U266 cells were highly sensitive to cerulenin treatment,with a dosage-related effect on metabolic activity,as a measure for cell proliferation.U266 cells treated with 20μg/ml cerulenin for 12 and 24 h also showed early sign of apoptosis with 56.9%and 69.3%Annexin V+/PI ?cells,and late apoptotic and necrotic cells with 3.2%and 17.6%Annexin V+/PI +cells.Conclusion:Increased FAS expression existed in multiple myeloma samples and human myeloma cell lines.Cerulenin greatly inhibited metabolic activity/cell proliferation of U266 cells and induced apoptosis,suggesting that FAS is an effective target for pharmacological therapy in human multiple myeloma.

Analysis of fatty acid composition of sea cucumber Apostichopus japonicus using multivariate statistics

Fatty acids(FAs) provide energy and also can be used to trace trophic relationships among organisms.Sea cucumber Apostichopus japonicus goes into a state of aestivation during warm summer months.We examined fatty acid profiles in aestivated and non-aestivated A.japonicus using multivariate analyses(PERMANOVA,MDS,ANOSIM,and SIMPER).The results indicate that the fatty acid profiles of aestivated and non-aestivated sea cucumbers differed significantly.The FAs that were produced by bacteria and brown kelp contributed the most to the differences in the fatty acid composition of aestivated and nonaestivated sea cucumbers.Aestivated sea cucumbers may synthesize FAs from heterotrophic bacteria during early aestivation,and long chain FAs such as eicosapentaenoic(EPA) and docosahexaenoic acid(DHA) that produced from intestinal degradation,are digested during deep aestivation.Specific changes in the fatty acid composition of A.japonicus during aestivation needs more detailed study in the future.

Application of Biochemical Fulvic Acid Potassium in Transplantation of Trees

[Objective]The paper was to clarify the application of biochemical fulvic acid potassium on the survival rate and growth of various trees transplanted in the process of landscaping.[Method]Two experimental treatments(i.e.decomposed organic fertilizer+biochemical fulvic acid potassium water soluble fertilizer,decomposed organic fertilizer+compound fertilizer)were designed to determine the changes in physical and chemical properties before and after soil treatment,and the survival rate,plant height and ground diameter of four different cultivated plants within one year,and the effects of applying biochemical fulvic acid potassium on cultivated plants were investigated.[Result]The soil organic matter,total nitrogen,alkali-hydrolyzable nitrogen,soil available phosphorus,soil available potassium and p H value in the soil treated with decomposed organic fertilizer+biochemical fulvic acid potassium soluble fertilizer,and decomposed organic fertilizer+compound fertilizer increased significantly,and the soil bulk density decreased obviously.The survival rates,plant heights and ground diameters of four different cultivated plants were significantly improved after application of decomposed organic fertilizer+biochemical fulvic acid potassium water soluble fertilizer,and decomposed organic fer-tilizer+compound fertilizer(P<0.05).[Conclusion]The application of biochemical fulvic acid potassium on cultivated plants effectively improved soil fertility,increased the utilization of nitrogen,phosphorus and potassium,improved the growth of plants,and promoted the growth of landscaping plants after transplantation.

Determination of Formation Constants of Co^2＋,Ni^2＋,Cu^2＋and Zn^2＋ Complexes with Humic and Fulvic Acids by Potentionmetric Titration Method

The formation constants of Co^2+,Ni^2+,Cu^2+ and Zn^2+ complexes with humic acid(HA) and fulvic acid(FA) in red soil wrer determined by the potentiometric titration method.The constants as a function of composition of the complexation solutions were obtained by two graphical approaches respetively,The formation constants decreased with increasing concentration of metal in the solution,The results provide unambiguous evidence for the heterogeneity of the function groups of humic substances,the formation constants of FA were much smaller than those of HA,and the formation constants of Cu^2+ were much greater than those of Co^2+ ,Ni^2+ and Zn^2+,The potentiometric titration methon for determining formation constants are also discussed in the article.

Acid-base buffer effect of fulvic acid and barium fulvate from weathered coal

The acid-base buffer characteristics of fulvic acid (FA) and barium fulvate (BaFA)were analyzed. Each share of the sample or model agents (phthalic acid and salicylic acid)were separately mixed into a series of shares of dilute solutions of HCI or NaOH with a series of concentration. The original pH values of the solutions were arranged from 2 to 13.Final balanced pH of each share was measured. The pH changes show that FA and BaFApossess buffer ability, whereas the model agents do not. The tendency of balanced pHvalues was 5.4 for FA and 7.4 for BaFA, whereas the original pH was 4.0-8.5; balancedpH changed little. At room temperature, the maximum buffer capacities were as follows:18.11 mmol hydroxyl per gram FA, 11.25 mmol hydroxyl per gram BaFA, 1.19 mmol protonper gram FA, and 1.45 mmol proton per gram BaFA. Mathematics analysis shows thatlogarithm of buffer capacities of FA and BaFA is linearly dependent on original pH. Compared with BaFA and model agents, it is concluded that FA buffer capacity against hydroxylrelies not only on its acidic groups, BaFA buffer capacity against hydroxyl does not rely onits acidic groups, and FA buffer capacity against proton is not related with its carboxyl andphenolic hydroxyl group. The pH values of FA-water solutions with different concentrationsfrom 1 to 10 grams per liter were measured. Their pH values were slightly affected by itsconcentration. Thus, FA possesses a much stronger buffer ability against water dilutionthan common buffer agent. All the pH values of FA water solutions were very nearby 5.4,just the same as the balanced pH tendency for adding FA.

酸性矿山废水中FA-Sb胶体的形成研究

为探究酸性矿山废水(AMD)中天然有机质(NOM)和锑(Sb)形成胶体的机制,本文采用富里酸(FA)作为代表性NOM与Sb(Ⅲ)反应,研究在此过程中FA-Sb胶体的形成情况。本研究通过室内模拟实验研究了不同初始C_((FA))/Sb条件下FA-Sb胶体的形成过程,并采用X射线光电子能谱(XPS)和傅里叶变换红外光谱(FT-IR)对FA-Sb胶体进行了表征。实验结果表明,FA可显著促进Sb与FA形成颗粒态与胶体态;初始摩尔C_((FA))/Sb越高,FA-Sb胶体的产生量越大,Zeta电位越低,颗粒粒径越小。在此过程中,FA含有的羟基等含氧官能团促进了FA-Sb胶体的形成,FA带有的负电促进了FA-Sb胶体的稳定。AMD中的少量Sb(Ⅲ)可能被FA在光照条件下产生的活性氧化物种氧化,且Sb(Ⅲ)的氧化率随C_((FA))/Sb比(0~2000)的增加而逐渐增大。该研究结果从胶体地球化学角度揭示了AMD中FA与Sb之间的相互作用关系,为深入认识AMD中Sb的地球化学行为提供了一定见解。

The damage effects of oxy free radicals and fulvic acid on chondrocytes

The damage effects of oxy free radical and fulvic acid on cultivated chicken embryo chondrocytes were studied. The results show that the growrth of chondrocytes is inhibited and the morphology of the cells altered. The collagen synthesizing capability of the damaged cell changes somewhat. A noteworthy change of the type of collagen synthesized by the abnormal cells was observed by CMC-chromatography and amino acid analysis. The results indicated that the abnonml cells tend to synthesize type I instead of type II collagen, which is synthesized and secreted by the intact chondrocyte.

The oxidation damage of type II collagen by oxy free radicals and fulvic acid

The features of oxidative damage to type II collagen from pig cartilage, induced by · OH, O2- and fulvic acid from epidemic district of KBD, were studied in vitro. The results from amino acid analysis of the damaged collagen are characterized by a decrease in hydroxyproline and proline contents, and an increase in glutamic acid content. The change arc dependent on·OH and FA concentration. It is postulated that the FA or other toxic xenobiotics induce the generation of free radicals, which play the role of the trigger in KBD development.