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Pretreating and normalizing metabolomics data for statistical analysis 被引量:1
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作者 Jun Sun Yinglin Xia 《Genes & Diseases》 SCIE CSCD 2024年第3期188-205,共18页
Metabolomics as a research field and a set of techniques is to study the entire small molecules in biological samples.Metabolomics is emerging as a powerful tool generally for pre-cision medicine.Particularly,integrat... Metabolomics as a research field and a set of techniques is to study the entire small molecules in biological samples.Metabolomics is emerging as a powerful tool generally for pre-cision medicine.Particularly,integration of microbiome and metabolome has revealed the mechanism and functionality of microbiome in human health and disease.However,metabo-lomics data are very complicated.Preprocessing/pretreating and normalizing procedures on metabolomics data are usually required before statistical analysis.In this review article,we comprehensively review various methods that are used to preprocess and pretreat metabolo-mics data,including MS-based data and NMR-based data preprocessing,dealing with zero and/or missing values and detecting outliers,data normalization,data centering and scaling,data transformation.We discuss the advantages and limitations of each method.The choice for a suitable preprocessing method is determined by the biological hypothesis,the characteristics of the data set,and the selected statistical data analysis method.We then provide the perspective of their applications in the microbiome and metabolome research. 展开更多
关键词 Data centering and scaling Data normalization Data transformation Missing values MS-Baseddata preprocessing NMRData preprocessing OUTLIERS Preprocessing/pretreatment
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Multiple pretreatments can effectively improve the functionality of mesenchymal stem cells 被引量:1
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作者 Xin-Xing Wan Xi-Min Hu Kun Xiong 《World Journal of Stem Cells》 SCIE 2024年第2期58-63,共6页
In this editorial,we offer our perspective on the groundbreaking study entitled“Hypoxia and inflammatory factor preconditioning enhances the immunosup-pressive properties of human umbilical cord mesenchymal stem cell... In this editorial,we offer our perspective on the groundbreaking study entitled“Hypoxia and inflammatory factor preconditioning enhances the immunosup-pressive properties of human umbilical cord mesenchymal stem cells”,recently published in World Journal of Stem Cells.Despite over three decades of research on the clinical application of mesenchymal stem cells(MSCs),only a few therapeutic products have made it to clinical use,due to multiple preclinical and clinical challenges yet to be addressed.The study proved the hypoxia and inflammatory factor preconditioning led to higher immunosuppressive effects of MSCs without damaging their biological characteristics,which revealed the combination of inflammatory factors and hypoxic preconditioning offers a promising approach to enhance the function of MSCs.As we delve deeper into the intricacies of pretreat-ment methodologies,we anticipate a transformative shift in the landscape of MSC-based therapies,ultimately contributing to improved patient outcomes and advancing the field as a whole. 展开更多
关键词 Mesenchymal stem cells Inflammatory factor HYPOXIA PRETREATMENT
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CAOSA-extracted lignin improves enzymatic hydrolysis of cellulose
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作者 Sen Ma Zheng Li +5 位作者 Jonathan Sperry Xing Tang Yong Sun Lu Lin Jian Liu Xianhai Zeng 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第7期1101-1111,共11页
The conversion of biomass into sugar platform compounds is very important for the biorefinery industry.Pretreatment is essential to the biomass of the sugar platform,however,the lignin obtained by pretreatment,as a ke... The conversion of biomass into sugar platform compounds is very important for the biorefinery industry.Pretreatment is essential to the biomass of the sugar platform,however,the lignin obtained by pretreatment,as a key part of lignocellulose,generally has a passive effect on the enzymatic hydrolysis of cellulose into sugars.In this study,p-TsOH(p-toluenesulfonic acid),DES(Deep eutectic solvent)and CAOSA(cooking with active oxygen and solid alkali)pretreatment ways were used to fraction lignin from bamboo biomass.After CAOSA treatment,the hydrolysis efficiency of the pulp was 95.57%.Moreover,the effect of different treatment methods on lignin properties was studied and the promotion effect of lignin was investigated by adding it to the cellulose enzymatic hydrolysis system.In this work,the results showed that CAOSA-extracted lignin with lower D(1.31-1.25)had a better adsorption effect on the enzyme protein.p-TsOH-extracted lignin with a larger S/G ratio enhanced the inhibition of enzymatic hydrolysis.In addition,the presence of-COOHs in lignin could reduce its inhibitory effect on cellulose saccharification. 展开更多
关键词 Biomass pretreatment CAOSA Cellulose hydrolysis LIGNIN ENZYME
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预处理技术--家庭生物废弃物处理过程中的微塑料制造者
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作者 Tian Hu Fan Lü +4 位作者 Zhan Yang Zhenchao Shi Yicheng Yang Hua Zhang Pinjing He 《Engineering》 SCIE EI CAS CSCD 2024年第1期116-126,共11页
Mechanical pretreatment is an indispensable process in biological treatment plants that remove plastics and other impurities from household biogenic waste(HBW).However,the imperfect separation of plastics in these pre... Mechanical pretreatment is an indispensable process in biological treatment plants that remove plastics and other impurities from household biogenic waste(HBW).However,the imperfect separation of plastics in these pretreatment methods has raised concerns that they pose a secondary formation risk for microplastics(MPs).To validate this presumption,herein,quantities and properties of plastic debris and MPs larger than 50 μm were examined in the full chain of three different pretreatment methods in six plants.These facilities received HBW with or without prior depackaging at the source.The key points in the secondary formation of MPs were identified.Moreover,flux estimates of MPs were released,and an analysis of MPs sources was provided to develop an overview of their fate in HBW pretreatment.Pretreated output can contain a maximum of(1673±279) to(3198±263) MP particles per kilogram of wet weight(particles·kg^(-1)ww) for those undepackaged at source,and secondary MPs formation is primarily attributed to biomass crushers,biohydrolysis reactors,and rough shredders.Comparatively,HBW depackaged at the source can greatly reduce MPs by 8%-72%,regardless of pretreatment processes.Before pretreatment,4.6-205.6 million MP particles were present in 100 tonnes of HBW.MPs are produced at a rate of 741.11-33124.22 billion MP particles annually in anaerobic digester feedstock(ADF).This study demonstrated that HBW pretreatment is a competitive source of MPs and emphasized the importance of implementing municipal solid waste segregation at the source.Furthermore,depackaging biogenic waste at the source is recommended to substantially alleviate the negative effect of pretreatment on MPs formation. 展开更多
关键词 Microplastics Plastic debris Household biogenic waste Depackage PRETREATMENT
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Role of tannin pretreatment in flotation separation of magnesite and dolomite
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作者 Xiufeng Gong Jin Yao +5 位作者 Jun Guo Bin Yang Haoran Sun Wanzhong Yin Yulian Wang Yafeng Fu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第3期452-461,共10页
Flotation separation of magnesite and its calcium-containing carbonate minerals is a difficult problem.Recently,new regulat-ors have been proposed for magnesite flotation decalcification,although traditional regulator... Flotation separation of magnesite and its calcium-containing carbonate minerals is a difficult problem.Recently,new regulat-ors have been proposed for magnesite flotation decalcification,although traditional regulators such as tannin,water glass,sodium carbon-ate,and sodium hexametaphosphate are more widely used in industry.However,they are rarely used as the main regulators in research because they perform poorly in magnesite and dolomite single-mineral flotation tests.Inspired by the limonite presedimentation method and the addition of a regulator to magnesite slurry mixing,we used a tannin pretreatment method for separating magnesite and dolomite.Microflotation experiments confirmed that the tannin pretreatment method selectively and largely reduces the flotation recovery rate of dolomite without affecting the flotation recovery rate of magnesite.Moreover,the contact angles of the tannin-pretreated magnesite and dolomite increased and decreased,respectively,in the presence of NaOl.Zeta potential and Fourier transform infrared analyses showed that the tannin pretreatment method efficiently hinders NaOl adsorption on the dolomite surface but does not affect NaOl adsorption on the magnesite surface.X-ray photoelectron spectroscopy and density functional theory calculations confirmed that tannin interacts more strongly with dolomite than with magnesite. 展开更多
关键词 tannin pretreatment selective inhibition flotation separation MAGNESITE DOLOMITE
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Thermal pretreatment of willow branches impacts yield and pore development of activated carbon in subsequent activation with ZnCl_(2) via modifying cellulose structure
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作者 Linghui Kong Chao Li +7 位作者 Runxing Sun Shu Zhang Yi Wang Jun Xiang Song Hu Dong Wang Chuanjun Leng Xun Hu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第5期227-237,共11页
Development of pore structures of activated carbon(AC)from activation of biomass with ZnCl_(2) relies on content and structure of cellulose/hemicellulose in the feedstock.Thermal pretreatment of biomass could induce d... Development of pore structures of activated carbon(AC)from activation of biomass with ZnCl_(2) relies on content and structure of cellulose/hemicellulose in the feedstock.Thermal pretreatment of biomass could induce dehydration and/or aromatization to change the structure of cellulose/hemicellulose.This might interfere with evolution of structures of AC,which was investigated herein via thermal pretreatment of willow branch(WB)from 200 to 360℃and the subsequent activation with ZnCl_(2) at 550℃.The results showed that thermal pretreatment at 360℃(WB-360)could lead to substantial pyrolysis to form biochar,with a yield of 31.9%,accompanying with nearly complete destruction of cellulose crystals and remarkably enhanced aromatic degree.However,cellulose residual in WB-360 could still be activated to form AC-360 with specific surface area of 1837.9 m~2·g^(-1),which was lower than that in AC from activation of untreated WB(AC-blank,2077.8 m~2·g^(-1)).Nonetheless,the AC-200 from activation of WB-200 had more developed pores(2113.9 m~2·g^(-1))and superior capability for adsorption of phenol,due to increased permeability of ZnCl_(2) to the largely intact cellulose structure in WB-200.The thermal pretreatment did increase diameters of micropores of AC but reduced the overall yield of AC(26.8%for AC-blank versus 18.0%for AC-360),resulting from accelerated cracking but reduced intensity of condensation.In-situ infrared characterization of the activation showed that ZnCl_(2) mainly catalyzed dehydration,dehydrogenation,condensation,and aromatization but not cracking,suppressing the formation of derivatives of cellulose and lignin in bio-oil.The thermal pretreatment formed phenolic-OH and C=O with higher chemical innerness,which changed the reaction network in activation,shifting morphology of fibrous structures in AC-blank to“melting surface”in AC-200 or AC-280. 展开更多
关键词 Thermal pretreatment Activation with ZnCl_(2) Willow branch Activated carbon Biochar
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Retinal ischemia-reperfusion injury and pretreatment with Lycium barbarum glycopeptide
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作者 Yan-Xia Wu Shuo Yin +3 位作者 Shan-Shan Song Xiang Liu Yu-Xuan Deng Xue-Jing Lu 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2024年第9期1599-1605,共7页
AIM:To investigate the antioxidant protective effect of Lycium barbarum glycopeptide(LbGP)pretreatment on retinal ischemia-reperfusion(I/R)injury(RIRI)in rats.METHODS:RIRI was induced in Sprague Dawley rats through an... AIM:To investigate the antioxidant protective effect of Lycium barbarum glycopeptide(LbGP)pretreatment on retinal ischemia-reperfusion(I/R)injury(RIRI)in rats.METHODS:RIRI was induced in Sprague Dawley rats through anterior chamber perfusion,and pretreatment involved administering LbGP via gavage for 7d.After 24h of reperfusion,serum alanine aminotransferase(ALT),aspartate aminotransferase(AST),and creatinine(CREA)levels,retinal structure,expression of Caspase-3 and Caspase-8,superoxide dismutase(SOD)activity,and malondialdehyde(MDA)in the retina were measured.RESULTS:The pretreatment with LbGP effectively protected the retina and retinal tissue from edema and inflammation in the ganglion cell layer(GCL)and nerve fiber layer(NFL)of rats subjected to RIRI,as shown by light microscopy and optical coherence tomography(OCT).Serum AST was higher in the model group than in the blank group(P=0.042),but no difference was found in ALT,AST,and CREA across the LbGP groups and model group.Caspase-3 expression was higher in the model group than in the blank group(P=0.006),but no difference was found among LbGP groups and the model group.Caspase-8 expression was higher in the model group than in the blank group(P=0.000),and lower in the 400 mg/kg LbGP group than in the model group(P=0.016).SOD activity was lower in the model group than in the blank group(P=0.001),and the decrease was slower in the 400 mg/kg LbGP group than in the model group(P=0.003).MDA content was higher in the model group than in the blank group(P=0.001),and lower in the 400 mg/kg LbGP group than in the model group(P=0.016).The pretreatment with LbGP did not result in any observed liver or renal toxicity in the model.CONCLUSION:LbGP pretreatment exhibits dosedependent anti-inflammatory,and antioxidative effects by reducing Caspase-8 expression,preventing declines of SOD activity,and decreasing MDA content in the RIRI rat model. 展开更多
关键词 retinal ischemia-reperfusion Lycium barbarum glycopeptide PRETREATMENT ANTI-INFLAMMATORY ANTIOXIDATIVE RAT
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Effective separation of coal gasification fine slag: Role of classification and ultrasonication in enhancing flotation
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作者 Rui Han Anning Zhou +4 位作者 Ningning Zhang Zhen Li Mengyan Cheng Xiaoyi Chen Tianhao Nan 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第6期867-880,共14页
Effective separation of residual carbon and ash is the basis for the resource utilization of coal gasification fine slag(CGFS).The conventional flotation process of CGFS has the bottlenecks of low carbon recovery and ... Effective separation of residual carbon and ash is the basis for the resource utilization of coal gasification fine slag(CGFS).The conventional flotation process of CGFS has the bottlenecks of low carbon recovery and high collector dosage.In order to address these issues,CGFS sample taken from Shaanxi,China was used as the study object in this paper.A new process of size classification-fine grain ultrasonic pretreatment flotation(SC-FGUF)was proposed and its separation effect was compared with that of wholegrain flotation(WGF)as well as size classification-fine grain flotation(SC-FGF).The mechanism of its enhanced separation effect was revealed through flotation kinetic fitting,flotation flow foam layer stability,particle size composition,surface morphology,pore structure,and surface chemical property analysis.The results showed that compared with WGF,pre-classification could reduce the collector dosage by 84.09%and the combination of pre-classification and ultrasonic pretreatment could increase the combustible recovery by 17.29%and up to 93.46%.The SC-FGUF process allows the ineffective adsorption of coarse residual carbon to collector during flotation stage to be reduced by pre-classification,and the tightly embedded state of fine CGFS particles is disrupted and surface oxidizing functional group occupancy was reduced by ultrasonic pretreatment,thus carbon and ash is easier to be separated in the flotation process.In addition,some of the residual carbon particles were broken down to smaller sizes in the ultrasonic pretreatment,which led to an increase in the stability of flotation flow foam layer and a decrease in the probability of detachment of residual carbon particles from the bubbles.Therefore,SCFGUF could increase the residual carbon recovery and reduce the flotation collector dosage,which is an innovative method for carbon-ash separation of CGFS with good application prospect. 展开更多
关键词 Coal gasification fine slag Size classification Ultrasonic pretreatment FLOTATION Carbon recovery
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Synergetic Bioproduction of Short-Chain Fatty Acids from Waste Activated Sludge Intensified by the Combined Use of Potassium Ferrate and Biosurfactants
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作者 CHEN Yanyan YAO Shuo +2 位作者 ZHANG Dahai LI Xianguo FENG Lijuan 《Journal of Ocean University of China》 SCIE CAS CSCD 2024年第3期695-709,共15页
The synergetic effect and underlying mechanism of potassium ferrate(PF)with tea saponin(TS,a biosurfactant)in producing short chain fatty acids(SCFAs)from anaerobic fermentation of waste activated sludge(WAS)were expl... The synergetic effect and underlying mechanism of potassium ferrate(PF)with tea saponin(TS,a biosurfactant)in producing short chain fatty acids(SCFAs)from anaerobic fermentation of waste activated sludge(WAS)were explored in this work.Experimental results showed that 0.2 g PF(g TSS)^(-1)(total suspended solid)combined with 0.02 g TS(g TSS)^(-1) could further improve SCFAs’production,and the maximum SCFAs content reached 2008.7 mg COD L^(-1),which is 1.2 and 4.5 times higher than those with PF and TS individually added,respectively,and 5.3 times higher than that of blank WAS on Day 12.In the model substrates experiments,the degradation rates of bovine serum albumin and dextran with combination of PF and TS were 41.3%±0.1% and 48.5%±0.06%,respectively,on Day 3,which are lower than those in blank WAS(with degradation rates of 72.3%±0.5%and 90.3%±0.3%).It was revealed that the oxidative effect of PF and the solubilization of TS caused more organic matters to be dissolved out from WAS,providing a large number of biodegradable substances for subsequent SCFAs production.While WAS pretreated with the combination of PF and TS,the relative abundances of Firmicutes increased from 6.4%(blank)to 38.6%,and that of Proteobacteria decreased from 41.8%(blank)to 21.8%.The combination of PF and TS promoted the hydrolysis process of WAS by enriching Firmicutes,and then increased acetic acid production by inhibiting Proteobacteria that consumed SCFAs.Meanwhile,at the genus level,acidogenesis bacteria(e.g.,Proteiniclasticum and Petrimonas)were enriched whereas SCFAs consuming bacteria(e.g.,Dokdonella)were inhibited. 展开更多
关键词 waste activated sludge anaerobic fermentation potassium ferrate BIOSURFACTANT PRETREATMENT
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An efficient method for constructing a random insertional mutant library for forward genetics in Nannochloropsis oceanica
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作者 Zhongyi ZHANG Hang LIU +5 位作者 Xiaohui PAN Yanan ZONG Leili FENG Lixian LIU Li GUO Guanpin YANG 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第1期216-225,共10页
Insertional mutation,phenotypic evaluation,and mutated gene cloning are widely used to clone genes from scratch.Exogenous genes can be integrated into the genome during non-homologous end joining(NHEJ)of the double-st... Insertional mutation,phenotypic evaluation,and mutated gene cloning are widely used to clone genes from scratch.Exogenous genes can be integrated into the genome during non-homologous end joining(NHEJ)of the double-strand breaks of DNA,causing insertional mutation.The random insertional mutant library constructed using this method has become a method of forward genetics for gene cloning.However,the establishment of a random insertional mutant library requires a high transformation efficiency of exogenous genes.Many microalgal species show a low transformation efficiency,making constructing random insertional mutant libraries difficult.In this study,we established a highly efficient transformation method for constructing a random insertional mutant library of Nannochloropsis oceanica,and tentatively tried to isolate its genes to prove the feasibility of the method.A gene that may control the growth rate and cell size was identified.This method will facilitate the genetic studies of N.oceanica,which should also be a reference for other microalgal species. 展开更多
关键词 Nannochloropsis oceanica genetic transformation random insertional mutant library zeocin pretreatment forward genetics
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On-site rapid detection of multiple pesticide residues in tea leaves by lateral flow immunoassay
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作者 Junxia Gao Tianyi Zhang +7 位作者 Yihua Fang Ying Zhao Mei Yang Li Zhao Ye Li Jun Huang Guonian Zhu Yirong Guo 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2024年第2期276-283,共8页
The application of pesticides (mostly insecticides and fungicides) during the tea-planting process will undoubtedly increase the dietary risk associated with drinking tea. Thus, it is necessary to ascertain whether pe... The application of pesticides (mostly insecticides and fungicides) during the tea-planting process will undoubtedly increase the dietary risk associated with drinking tea. Thus, it is necessary to ascertain whether pesticide residues in tea products exceed the maximum residue limits. However, the complex matrices present in tea samples comprise a major challenge in the analytical detection of pesticide residues. In this study, nine types of lateral flow immunochromatographic strips (LFICSs) were developed to detect the pesticides of interest (fenpropathrin, chlorpyrifos, imidacloprid, thiamethoxam, acetamiprid, carbendazim, chlorothalonil, pyraclostrobin, and iprodione). To reduce the interference of tea substrates on the assay sensitivity, the pretreatment conditions for tea samples, including the extraction solvent, extraction time, and purification agent, were optimized for the simultaneous detection of these pesticides. The entire testing procedure (including pretreatment and detection) could be completed within 30 min. The detected results of authentic tea samples were confirmed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), which suggest that the LFICS coupled with sample rapid pretreatment can be used for on-site rapid screening of the target pesticide in tea products prior to their market release. 展开更多
关键词 Lateral flow immunoassay Rapid detection Pesticide multi-residue Tea matrix Sample rapid pretreatment
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Technological advancements in millet dehulling and polishing process: An insight into pretreatment methods, machineries and impact on nutritional quality
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作者 Shagolshem Mukta Singh Jayasree Joshi T P.Srinivasa Rao 《Grain & Oil Science and Technology》 CAS 2024年第3期186-195,共10页
Millets are widely recognized for their nutritional significance;however, the methods employed for their processing are currently lacking. This article primarily focuses on the advanced technologies and progressions i... Millets are widely recognized for their nutritional significance;however, the methods employed for their processing are currently lacking. This article primarily focuses on the advanced technologies and progressions in millet dehulling and polishing. These technologies operate based on the fundamental principles of compression-shearing, abrasion-friction, and centrifugal-impact forces. Processing of millets can be challenging because of the physical characteristics and tight attachment of hull and bran to the endosperm. However, several dehullers have been designed to solve this problem for different kinds of millets. In addition, the nutritional and anti-nutritional characteristics undergo alterations due to both dehulling and polishing processes. These alterations are thoroughly examined and discussed in this article. Specifically, anti-nutrients such as tannins and phytate are predominantly found in the outer pericarp of the grain and experience a reduction after undergoing dehulling and polishing. The nutritional properties are also subjected to a reduction;however, this reduction can be mitigated by subjecting the grains to certain pretreatments before dehulling and polishing. These treatments serve to enhance dehulling efficiency and nutrient digestibility while simultaneously reducing the presence of anti-nutrients. Novel thermal and non-thermal methodologies such as microwave, hydrothermal, high-pressure processing, and ohmic heating can be employed for processing millets, thereby diminishing the loss of nutrients. Additional research can be carried out to investigate their impact on the dehulling and polishing of millets. 展开更多
关键词 MILLETS DEHULLING POLISHING PRETREATMENT Novel thermal and non-thermal techniques
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Research Progress of QuEChERS Pretreatment Technique in the Detection of Multiple Pesticide Residues
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作者 Bo LIU Dawei WANG +3 位作者 Yuhang GUO Xuehua WANG Lei WANG Yajuan SONG 《Agricultural Biotechnology》 2024年第2期10-11,37,共3页
The QuEChERS extraction technique is a pretreatment technique that has been rapidly applied in recent years and is widely used in the field of pesticide residues with many advantages. This technique is based on solid ... The QuEChERS extraction technique is a pretreatment technique that has been rapidly applied in recent years and is widely used in the field of pesticide residues with many advantages. This technique is based on solid phase extraction (SPE), which uses the interaction between adsorbent and impurities in the matrix to achieve the purpose of purification. The method has easier operation and better purification effect than SPE. In this paper, the research progress of the QuEChERS technique in pesticide residue detection in different fields in recent years and its future development were reviewed, hoping to provide reference for further development and utilization of the QuEChERS technique in pesticide residue detection in the future. 展开更多
关键词 QUECHERS PRETREATMENT Pesticide residues Research progress
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Change Point Analysis to Detect the Effect of Pruning Severity on Tree Growth
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作者 Yutaka Iguchi 《Open Journal of Forestry》 2024年第1期67-73,共7页
The effect of pruning severity on tree growth was analyzed by change point detection using segmented regression. The present study applied this analysis to a well-known published data set including diameter growth res... The effect of pruning severity on tree growth was analyzed by change point detection using segmented regression. The present study applied this analysis to a well-known published data set including diameter growth response, tree age, pruning severity and pretreatment crown size. First, multiple regression analysis was performed to assess the effect of tree age, pruning severity and pretreatment crown size on diameter growth response. Next, segmented regression analysis was performed to assess the effect of pruning severity on diameter growth response. The results of the multiple regression showed that diameter growth response was significantly influenced by pruning severity and pretreatment crown size. The results of the segmented regression showed that in the whole data set, an abrupt change toward a decrease in diameter growth response was detected at 25% of the live crown removed. However, in the group of fully crowned and open-grown, diameter growth response continuously decreased with increasing pruning severity with no significant abrupt change, whereas in the group of 70% - 90% live crown, diameter growth response did not significantly decrease up to the break point (53% crown removed) and then abruptly decreased. This may be the first study to show the numerical evaluation of the effect of pruning severity on tree growth by change point analysis. 展开更多
关键词 Regression Analysis Crown Removal Limit Tree Growth PRETREATMENT Abrupt Change
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Ultrasound application in alkaline pretreatment process of spodumene to improve particle floatability 被引量:2
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作者 Haoran Chu Lanlan Chen +3 位作者 Dongfang Lu Yuhua Wang Xiayu Zheng Guangli Zhu 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第7期883-891,共9页
Selective surface dissolution was found to be important in spodumene flotation. In this study, we proposed to introduce ultrasound into the pretreatment process to accelerate particle vibration and cavitation, as well... Selective surface dissolution was found to be important in spodumene flotation. In this study, we proposed to introduce ultrasound into the pretreatment process to accelerate particle vibration and cavitation, as well as the migration of mineral surface components to solution. Micro-flotation results showed that the flotation recovery of spodumene can be 86.08% by ultrasound pretreatment, but only 39.30% by traditional mechanical agitation pretreatment. Compared with traditional mechanical agitation, ultrasonic pretreatment can shorten the pretreatment process, reduce the dosage of agents, reduce the mechanical agitation speed, and improve the efficiency of the pretreating process. Inductively coupled plasma analysis showed that, in the ultrasonic system, the amount of Li, Al, and Si species in the solution was twice as much as those in the traditional preprocessing system. Moreover, the scanning electron microscope results demonstrated a larger surface dissolution area in the ultrasonic system. X-Ray photoelectron spectroscopy results showed that the atomic concentration of Si species on the spodumene surface decreased, whereas the relative atomic concentrations of Li and Al species increased, indicating that the ultrasound effect strengthened the selective dissolution of elements on the mineral surface.The high-resolution spectra of O 1s showed that more collectors are adsorbed on the mineral surface treated by ultrasonic pretreatment. 展开更多
关键词 Ultrasonic pretreatment SPODUMENE FLOTATION Surface selective dissolution
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Polysaccharide impregnation:a pretreatment method for improving scallop quality and flavor 被引量:2
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作者 Mengwen Sun Huimin Lin +2 位作者 Chen Zeng Shanggui Deng Alessandra Guidi 《Food Science and Human Wellness》 SCIE CSCD 2023年第2期546-554,共9页
The quality and flavor of scallops changes during the fresh dry rehydration process.In order to control the changes after rehydration,a scallop pretreatment method was adopted.The pretreatment method involved impregna... The quality and flavor of scallops changes during the fresh dry rehydration process.In order to control the changes after rehydration,a scallop pretreatment method was adopted.The pretreatment method involved impregnating fresh scallops with 0.2 g/100 m L konjac glucomannan(KGM),carrageenan(CA),and sodium alginate(SA)before the drying and rehydration process.After rehydration,the KGM treated samples had better water retention and the highest betaine content.The CA treated samples had a deepened yellow color and the highest content of flavoring amino acids(FAA)and inosine monophosphate(IMP).What’s more,a total of 77 volatile compounds were detected,with a maximum of 15 esters.The highest proportion in the four groups was eugenol,followed by n-hexadecanoic acid,methyl hexadecanoate etc.The SA group had no significant contribution in terms of quality and taste.The samples pretreated with KGM had the best quality,and those pretreated by CA had the best flavor. 展开更多
关键词 Pretreatment Amino acids ATP-related compounds BETAINE Volatile component
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Corrosion resistance of Mg-Al-LDH steam coating on AZ80 Mg alloy:Effects of citric acid pretreatment and intermetallic compounds 被引量:2
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作者 Jin-Meng Wang Xiang Sun +6 位作者 Liang Song M.Bobby Kannan Fen Zhang Lan-Yue Cui Yu-Hong Zou Shuo-Qi Li Rong-Chang Zeng 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第8期2967-2979,共13页
In this study,the effects of intermetallic compounds(Mg_(17)Al_(12)and Al_(8)Mn_(5))on the Mg-Al layered double hydroxide(LDH)formation mechanism and corrosion behavior of an in-situ LDH/Mg(OH)_(2)steam coatings on AZ... In this study,the effects of intermetallic compounds(Mg_(17)Al_(12)and Al_(8)Mn_(5))on the Mg-Al layered double hydroxide(LDH)formation mechanism and corrosion behavior of an in-situ LDH/Mg(OH)_(2)steam coatings on AZ80 Mg alloy were investigated.Citric acid(CA)was used to activate the alloy surface during the pretreatment process.The alloy was first pretreated with CA and then subjected to a hydrothermal process using ultrapure water to produce Mg-Al-LDH/Mg(OH)_(2)steam coating.The effect of different time of acid pretreatment on the activation of the intermetallic compounds was investigated.The microstructure and elemental composition of the obtained coatings were analyzed using FE-SEM,EDS,XRD and FT-IR.The corrosion resistance of the coated samples was evaluated using different techniques,i.e.,potentiodynamic polarization(PDP),electrochemical impedance spectrum(EIS)and hydrogen evolution test.The results indicated that the CA pretreatment significantly influenced the activity of the alloy surface by exposing the intermetallic compounds.The surface area fraction of Mg_(17)Al_(12)and Al_(8)Mn_(5)phases on the surface of the alloy was significantly higher after the CA pretreatment,and thus promoted the growth of the subsequent Mg-Al-LDH coatings.The CA pretreatment for 30 s resulted in a denser and thicker LDH coating.Increase in the CA pretreatment time significantly led to the improvement in corrosion resistance of the coated AZ80 alloy.The corrosion current density of the coated alloy was lower by three orders of magnitude as compared to the uncoated alloy. 展开更多
关键词 Magnesium alloy Citric acid pretreatment Steam coating Layered double hydroxide Intermetallic compounds Corrosion resistance
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Reducing damage extent of epoxy coating on magnesium substrate by Zr-enhanced PEO coating as an effective pretreatment 被引量:1
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作者 Z.Jamshidipour M.Toorani +1 位作者 M.Aliofkhazraei M.Mahdavian 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2023年第2期641-656,共16页
This research was undertaken to study the effect of Zr-enhanced plasma electrolytic oxidation(PEO) as a pretreatment on the corrosion performance of epoxy coating applied on Magnesium in 3.5 wt.% Na Cl solution. The p... This research was undertaken to study the effect of Zr-enhanced plasma electrolytic oxidation(PEO) as a pretreatment on the corrosion performance of epoxy coating applied on Magnesium in 3.5 wt.% Na Cl solution. The parameters of delamination index along with coating damage index were extracted through electrochemical impedance spectroscopy(EIS) tests to determine how Zr may affect the corrosion protection of duplex PEO/epoxy coated samples. Pull-off adhesion tests were also accomplished to form a better understanding of Zr-enhanced PEO coating’ function. According to the obtained results, the presence of Zr can reduce the damage to the coating system by almost twice. 展开更多
关键词 MAGNESIUM EIS PRETREATMENT PEO EPOXY Zirconyl nitrate
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Enhancing Hydrocarbon-Rich Bio-Oil Production via Catalytic Pyrolysis Fortified with Microorganism Pretreatment 被引量:1
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作者 Jiapeng Wang Bo Zhang +1 位作者 Haoqiang Cheng Zhixiang Xu 《Journal of Renewable Materials》 EI 2023年第10期3595-3612,共18页
A new method of pretreatment of corn straw with Phanerochaete chrysosporium combined with pyrolysis was proposed to improve the quality of bio-oil.The characterization results demonstrated that microbial pretreatment ... A new method of pretreatment of corn straw with Phanerochaete chrysosporium combined with pyrolysis was proposed to improve the quality of bio-oil.The characterization results demonstrated that microbial pretreatment was an effective method to decrease the lignin,which can achieve a maximum removal rate of 44.19%.Due to the destruction of biomass structure,the content of alkali metal and alkaline earth metal is reduced.Meanwhile,the depolymerized biomass structure created better pyrolysis conditions to promote the pyrolysis efficiency,increase the average decomposition rate of pyrolysis and reduce the residue.In fast pyrolysis,because of the enrichment of cellulose and the removal of lignin,the contents of acids,linear carbonyls,furans,and sugars increased while the contents of phenols decreased.As for the catalytic pyrolysis,due to the hydrocarbon pool reaction and shape selection deoxidation of ZSM-5 catalyst,the total hydrocarbon and aromatics contents can significantly increase up to 34.37%and 30.59%,respectively,with 3 weeks of pretreatment.And the the low molecular content of bio-oil increased after pretreatment,which can significantly benefit the entry of primary pyrolysis steam into the catalyst pores to improve the catalytic efficiency and hydrocarbon contents.This method provides a new treatment idea for high-quality utilization of biomass. 展开更多
关键词 Corn straw lignin Phanerochaete chrysosporium pretreatment AROMATICS
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Co-Production of High-Grade Dissolving Pulp,Furfural,and Lignin from Eucalyptus via Extremely Low Acid Pretreatment and Pulping Technologies and Catalysis 被引量:1
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作者 Chengxiang Li Yue Wu +3 位作者 Chunhui Zhang Yao Liu Qixuan Lin Junli Ren 《Journal of Renewable Materials》 SCIE EI 2023年第6期2555-2574,共20页
Hemicellulose and lignin are not reasonably utilized during the dissolved pulp preparation process.This work aimed to propose a process for the co-production of dissolving pulp,furfural,and lignin from eucalyptus.High... Hemicellulose and lignin are not reasonably utilized during the dissolved pulp preparation process.This work aimed to propose a process for the co-production of dissolving pulp,furfural,and lignin from eucalyptus.High-grade dissolving pulp was prepared from eucalyptus using a combination of extremely low acid(ELA)pretreatment,Kraft cooking,and elementary chlorine-free(ECF)bleaching.The obtained pre-hydrolysate was catalytic conversion into furfural in a biphasic system,and lignin during Kraft cooking and ECF was recovered.The process condition was discussed as well as the mass flow direction.The results showed that ELA pretreatment could effectively remove 80.1%hemicellulose.Compared with traditional hydrothermal pretreatment,the ELA pretreatment significantly increased the xylose yield from 5.05 to 14.18 g/L at 170℃ for 2 h,which had practical significance for furfural production.The 82.7%furfural yield and 82.9%furfural selectivity were obtained from xylose-rich pre-hydrolysate using NaCl as a phase modifier in a biphasic system with 4-methyl-2-pentanone(MIBK)as an organic phase by ion exchange resin catalysts at 190℃ for 2 h.Subsequently,the pretreated eucalyptus was subjected to Kraft cooking,and the optimal alkali amount was 14%.Then,the Kraft pulp was bleached using the O-D1-EP-D_(2) sequence,and dissolving pulp was obtained with an ISO brightness of 86.0%,viscosity of 463 mL/g,andα-cellulose content of 95.4%.The Kraft lignin which has a potential application was investigated by 2D-HSQC NMR and 31P NMR.The results showed that the S/G ratio of Kraft lignin was 1.93,and the content of phenolic hydroxyl groups was 2.53 mmol/g.Moreover,based on the above proposed process,30.5 g dissolving pulp,5.5 g furfural,and 21.2 g lignin per 100 g eucalyptus chips(oven dry)were produced.This research will provide new catalysis and pulping technical routes for dissolving pulp,furfural,and Kraft lignin products,which are in great demand in the chemical industry. 展开更多
关键词 EUCALYPTUS extremely low acid pretreatment dissolving pulp FURFURAL kraft lignin
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