Urinary nuclear magnetic resonance spectroscopy of a Bangladeshi cohort with hepatitis-B hepatocellular carcinoma: A biomarker corroboration study

AIM: To establish if a distinct urinary metabolic profile could be identified in Bangladeshi hepatitis-B hepatocellular carcinoma(HCC) patients compared to cirrhosis patients and controls. METHODS: Urine samples from 42 Bangladeshi patients with HCC(39 patients with hepatitis-B HCC), 47 with cirrhosis on a background of hepatitis B, 46 with chronic hepatitis B, and seven ethnically-matched healthy controls were analyzed using nuclear magnetic resonance(NMR) spectroscopy. A full dietary and medication history was recorded for each subject. The urinary NMR data were analyzed using principal component analysis(PCA) and orthogonal partial leastsquared discriminant analysis(OPLS-DA) techniques. Differences in relative signal levels of the most discriminatory metabolites identified by PCA and OPLSDA were compared between subject groups using an independent samples Kruskal-Wallis one-way analysis of variance(ANOVA) test with all pairwise multiple comparisons. Within the patient subgroups, the MannWhitney U test was used to compare metabolite levels depending on hepatitis B e-antigen(HBe Ag) status and treatment with anti-viral therapy. A BenjaminiHochberg adjustment was applied to acquire the level of significance for multiple testing, with a declared level of statistical significance of P < 0.05.RESULTS: There were significant differences in age(P < 0.001), weight(P < 0.001), and body mass index(P < 0.001) across the four clinical subgroups. Serum alanine aminotransferase(ALT) was significantly higher in the HCC group compared to controls(P < 0.001); serum α-fetoprotein was generally markedly elevated in HCC compared to controls; and serum creatinine levels were significantly reduced in the HCC group compared to the cirrhosis group(P = 0.004). A threefactor PCA scores plot showed clustering of the urinary NMR spectra from the four subgroups. Metabolites that contributed to the discrimination between the subgroups included acetate, creatine, creatinine, dimethyamine(DMA), formate, glycine, hippurate, and trimethylamine-N-oxide(TMAO). A comparison of relative metabolite levels confirmed that carnitine was significantly increased in HCC; and creatinine, hippurate, and TMAO were significantly reduced in HCC compared to the other subgroups. HBe Ag negative patients showed a significant increase in creatinine(P = 0.001) compared to HBe Ag positive patients in the chronic hepatitis B subgroup, whilst HBe Ag negative patients showed a significant decrease in DMA(P = 0.004) in the cirrhosis subgroup compared to HBe Ag positive patients. There were no differences in metabolite levels in HCC patients who did or did not receive antiviral treatment. CONCLUSION: Urinary NMR changes in Bangladeshi HCC were identified, corroborating previous findings from Egypt and West Africa. These findings could form the basis for the development of a cost-effective HCC dipstick screening test.

Using Nuclear Magnetic Resonance and MS/MS Spectroscopy for the Identification of Brodimoprim Metabolites in Rat Urine

Eight metabolites of brodimoprim (BDP) in rat urine were detected by NMR and ESIMS/MS. They were demethyl-BDP glucuronide, demethyl-BDP sulfurate, demethyl-BDP glucuronide sulfurate, alpha -hydroxyl-BDP, alpha -hydroxyl-BDP glucuronide, BDP sulfurate, N-oxide-BDP sulfurate, and alpha -hydroxyl-N-oxide-BDP sulfurate. All the sulfurates are reported for the first time.

Nuclear magnetic resonance spectroscopy is highly sensitive for lipid-soluble metabolites

Although the water-soluble metabolite profile of human mesenchymal stem cells is known, the lipid profile still needs further investigation. In this study, methanol-chloroform was used to extract lipid-soluble metabolites and perchloric acid was used to extract water-soluble metabolites. Fur- thermore, a dual phase extraction method using methanol-chloroform and water was used to obtain both water and lipid fractions simultaneously. All metabolite extractions were analyzed on a 9.4T high-resolution nuclear magnetic resonance spectrometer. Metabolite resonance peaks were as- signed in the acquired spectra according to the chemical shift, and the extraction efficiency of dif- ferent methods was compared. Results showed that in the spectra of water-soluble extracts, major metabolites comprised low molecular weight metabolites, including lactate, acetic acid, fatty acids, threonine, glutamic acid, creatine, choline and its derivatives, while in the spectra of lipid-soluble extracts, most metabolites were assigned to fatty acids. Among the different extraction procedures, perchloric acid was more efficient in extracting water-soluble metabolites and methanol-chloroform was efficient in extracting organic components compared with the dual phase extraction method. Nuclear magnetic resonance spectroscopy showed that as low as 0.7 mg organic yield was enough to obtain clear resonance peaks, while about 6.0 mg water-soluble yield was needed to obtain rela- tively favorable spectral lines. These results show that the efficiency of extracting water and lipid fractions is higher using perchloric acid and methanol-chloroform compared with dual phase ex- traction and that nuclear magnetic resonance spectroscopy is highly sensitive for analyzing lipid-soluble extracts.

Conformational Analysis of γ-Butyrolactones by Nuclear Magnetic Resonance Spectroscopy

A series of trans-4, 5-disubstituted -γ-butyrolactones are found to assume two different envelope conformations by means of nuclear magnetic resonance spectroscopy.

Crystallochemical Characterizations, Raman Spectroscopy and Studies Nuclear Magnetic Resonance (NMR) of Cu₂Zn(Sn, Si)S₄Compounds for Photovoltaic Applications

In this study, Si-doped Cu2ZnSnS4 compounds (Cu2ZnSn1-xSixS4, 0 ≤ x ≤ 1) were prepared by solid state reaction method for use of materials for photovoltaic cells. The structural and spectroscopic properties of the as-prepared compounds were studied by X-ray diffraction (XRD), 119Sn, 29Si and 65Cu Magic Angle Spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy. The Si-substitution in the Sn-site induces three different types of XRD patterns which depend largely on the Si content in the compound. For 0 ≤ x ≤ 0.5, XRD analysis reveals the presence of a pure tetragonal phase of solid solution with I-42m as a space group. Mixed tetragonal and orthorhombic phases were observed for 0.5 < x < 0.8, followed by a pure orthorhombic structure with a space group Pmn21 at high content of Si (x ≥ 0.8). 119Sn MAS NMR spectra show the presence of Sn/Si disorder as a function of the Si content. The 65Cu MAS NMR spectra of the quadratic solid solution confirm the presence of the two copper sites (Cu-2a and Cu-2c) at 780 ppm while in the case of the orthorhombic solid solution samples, a very broad band is observed. The optical properties were investigated of all compounds by UV-Vis diffuse reflectance and the obtained optical band gap values (1.31 to 2.43 eV) confirm a semiconductor character.

7.0T nuclear magnetic resonance evaluation of the amyloid beta(1–40) animal model of Alzheimer's disease: comparison of cytology verification

3.0T magnetic resonance spectroscopic imaging brain function in Alzheimer＇s disease. However, is a commonly used method in the research ot the role of 7.0T high-field magnetic resonance spectroscopic imaging in brain function of Alzheimer＇s disease remains unclear. In this study, 7.0T magnetic resonance spectroscopy showed that in the hippocampus of Alzheimer＇s disease rats, the N-acetylaspartate wave crest was reduced, and the creatine and choline wave crest was elevated. This finding was further supported by hematoxylin-eosin staining, which showed a loss of hippocampal neurons and more glial cells. Moreover, electron microscopy showed neuronal shrinkage and mitochondrial rupture, and scanning electron microscopy revealed small size hippocampal synaptic vesicles, incomplete synaptic structure, and reduced number. Overall, the results revealed that 7.0T high-field nuclear magnetic resonance spectroscopy detected the lesions and functional changes in hippocampal neurons of Alzheimer＇s disease rats in vivo, allowing the possibility for assessing the success rate and grading of the amyloid beta （1-40） animal model of Alzheimer＇s disease.

Proton nuclear magnetic resonance-based metabonomic models for non-invasive diagnosis of liver fibrosis in chronic hepatitis C:Optimizing the classification of intermediate fibrosis

AIM To develop metabonomic models(MMs), using 1 H nuclear magnetic resonance(NMR) spectra of serum, to predict significant liver fibrosis(SF: Metavir ≥ F2), advanced liver fibrosis(AF: METAVIR ≥ F3) and cirrhosis(C: METAVIR = F4 or clinical cirrhosis) in chronic hepatitis C(CHC) patients. Additionally, to compare the accuracy of the MMs with the aspartate aminotransferase to platelet ratio index(APRI) and fibrosis index based on four factors(FIB-4). METHODS Sixty-nine patients who had undergone biopsy in the previous 12 mo or had clinical cirrhosis were included. The presence of any other liver disease was a criterion for exclusion. The MMs, constructed using partial least squares discriminant analysis and linear discriminant analysis formalisms, were tested by cross-validation, considering SF, AF and C. RESULTS Results showed that forty-two patients(61%) presented SF, 28(40%) AF and 18(26%) C. The MMs showed sensitivity and specificity of 97.6% and 92.6% to predict SF; 96.4% and 95.1% to predict AF; and 100% and 98.0% to predict C. Besides that, the MMs correctly classified all 27(39.7%) and 25(38.8%) patients with intermediate values of APRI and FIB-4, respectively. CONCLUSION The metabonomic strategy performed excellently in predicting significant and advanced liver fibrosis in CHC patients, including those in the gray zone of APRI and FIB-4, which may contribute to reducing the need for these patients to undergo liver biopsy.

Nuclear magnetic resonance based metabolomics and liverdiseases:Recent advances and future clinical applications

Metabolomics is defined as the quantitative measurement of the dynamic multiparametric metabolic response of living systems to pathophysiological stimuli or genetic modification.It is an"omics"technique that is situated downstream of genomics,transcriptomics and proteomics.Metabolomics is recognized as a promising technique in the field of systems biology for the evaluation of global metabolic changes.During the last decade,metabolomics approaches have become widely used in the study of liver diseases for the detection of early biomarkers and altered metabolic pathways.It is a powerful technique to improve our pathophysiological knowledge of various liver diseases.It can be a useful tool to help clinicians in the diagnostic process especially to distinguish malignant and non-malignant liver disease as well as to determine the etiology or severity of the liver disease.It can also assess therapeutic response or predict drug induced liver injury.Nevertheless,the usefulness of metabolomics is often not understood by clinicians,especially the concept of metabolomics profiling or fingerprinting.In the present work,after a concise description of the different techniques and processes used in metabolomics,we will review the main research on this subject by focusing specifically on in vitro proton nuclear magnetic resonance spectroscopy based metabolomics approaches in human studies.We will first consider the clinical point of view enlighten physicians on this new approach and emphasis its future use in clinical"routine".

Substituent, Temperature and Solvent Effects on the Keto-Enol EQUILIBRIUM in <i>&beta;</i>-Ketoamides: A Nuclear Magnetic Resonance Study

Substituent, temperature and solvent effects on tautomeric equilibria in several β-ketoamides have been investigated by means of nuclear magnetic resonance spectroscopy (NMR). Keto-enol equilibrium predominates over the amide-imidol one. The relative stability of the individual tautomers and the corresponding equilibrium shifts are explained considering electronic and steric effects and tautomer stabilization via internal hydrogen bonds. In solution, these compounds exist mainly as ketoamide and Z-enolamide tautomers, both presenting intramolecular hydrogen bonds.

缴获电子烟油样品中75种合成大麻素的^(1)H qNMR定量分析研究

通过考察75种合成大麻素(SCRAs)的关键定量参数,首次建立了可用于电子烟油样品中75种SCRAs定量分析的核磁共振氢谱定量分析方法(^(1)H qNMR)。以1,3,5-三甲氧基苯为内标,将烟油样品经氘代甲醇稀释后直接进行分析。方法的定量下限为0.03%(质量分数),日内相对标准偏差(RSD)小于0.90%,日间RSD小于1.5%,基质加标回收率为93.3%~100%。采用1H qNMR法对19份缴获烟油样品中的4种合成大麻素3,3-二甲基-2-[1-(5-氟戊基)吲唑-3-甲酰氨基]丁酸甲酯(5F-ADB)、2-[1-(5-氟戊基)-1H-吲哚-3-甲酰氨基]-3,3-二甲基丁酸甲酯(5F-MDMB-PICA)、2-[1-(4-氟丁基)-1H-吲唑-3-甲酰氨基]-3,3-二甲基丁酸甲酯(4FMDMB-BUTINACA)、N-(1-氨基-3,3-二甲基-1-氧代丁-2-基)-1-丁基-1H-吲唑-3-甲酰胺(ADB-BUTINACA)进行定量分析,得到其含量范围为0.072%~2.056%。19份烟油样品的^(1)H qNMR定量结果与高效液相色谱法定量结果无显著性差异。该研究所建立的电子烟油中SCRAs的定量分析^(1)H qNMR法无需标准物质,操作简单,定量结果准确,解决了缺乏标准物质时复杂基质中SCRAs定量分析的难题。目前国内外尚未有采用^(1)H qNMR对电子烟油中75种SCRAs定量分析的报道。该研究进一步拓宽了^(1)H qNMR技术在禁毒领域的应用范围,为复杂基质中毒品和新精神活性物质的定量分析提供了新的思路。

低场^(1)H qNMR定量分析缴获毒品中氯胺酮及4种掺杂物

建立了可同时定量分析缴获毒品中氯胺酮、二甲基砜、磺胺、烟酰胺和非那西丁的低场氢谱核磁共振定量方法(LF-^(1)H qNMR),并将其定量能力与高场氢谱核磁共振定量方法(HF-^(1)H qNMR)进行了比较。对于LF-^(1)H qNMR,氯胺酮和4种掺杂物的日内相对标准偏差(RSD)、日间RSD和定量下限分别为0.50%~2.9%、2.0%~7.4%和0.3~5 mg/mL;对于HF-^(1)H qNMR,氯胺酮和4种掺杂物的日内RSD、日间RSD和定量下限分别为0.40%~1.1%、1.5%~3.9%和0.003~0.05 mg/mL。采用LF-^(1)H qNMR和HF-^(1)H qNMR对167份缴获氯胺酮样品进行定量分析,两种方法定量结果的相对误差均小于15%。LF-^(1)H qNMR测得氯胺酮、二甲基砜、磺胺、烟酰胺和非那西丁的纯度分别为13.5%~102.6%、1.1%~81.3%、2.6%~83.4%、1.8%~22.7%和3.4%~43.8%;HF-^(1)H qNMR测得的纯度分别为13.2%~99.7%、1.0%~78.4%、2.5%~75.9%、1.7%~21.3%和3.0%~43.5%。两种方法均可在不使用标准物质的情况下实现对氯胺酮和掺杂物的同时定量分析。虽然LF-^(1)H qNMR法的精密度和灵敏度略低于HF-^(1)H qNMR法,但其对复杂基质中多组分同时定量分析的能力较好。LF-^(1)H qNMR的仪器购置和日常维护费用远低于HF-^(1)H qNMR,未来将在法庭科学实验室中得到更广泛的应用。

~1H-qNMR法同时测定保健食品中抗坏血酸同分异构体含量

建立一种同时检测保健食品中抗坏血酸同分异构体含量的^(1)H-qNMR法。样品经偏磷酸水溶解超声提取,离心过膜后,取适量上清液于NMR管中,以对苯二酚为内标,以氘水为锁场溶剂,采用^(1)H-qNMR直接对保健食品中的抗坏血酸同分异构体进行定性定量分析。结果表明:抗坏血酸同分异构体和和内标对苯二酚能够很好地分离,2种抗坏血酸的质量浓度在400~4500μg/mL范围内线性良好,相关系数R~2>0.99。方法的日内精密度为1.14%~2.47%,日间精密度为2.22%~3.87%;检出限(LOD)分别为120和130μg/mL;平均加标回收率为93.38%~108.15%,相对标准偏差(RSDs,n=6)为1.74%~4.46%。该方法简单高效、重现性好,10 min内即可完成测样。对市售不同剂型保健食品进行检测,均未检出异抗坏血酸。该方法与高效液相色谱法检测结果无显著性差异,适用于保健食品中抗坏血酸同分异构体含量的测定。

农产品检测用脱氧雪腐镰刀菌烯醇纯度标准物质的研制

[目的]本文旨在研制脱氧雪腐镰刀菌烯醇(deoxynivalenol,DON)国家级纯度标准物质,为农产品中DON的检测等工作提供物质基础。[方法]利用质量平衡法和定量核磁共振法对DON纯度标准物质进行纯度定值。质量平衡法包括采用液相色谱面积归一化法测定DON主成分含量,采用卡尔费休库仑法测定纯度标准物质中水分含量,采用顶空气相色谱-质谱法测定挥发性杂质含量,以及采用电感耦合等离子质谱法测定无机离子杂质含量。定量核磁共振法采用苯甲酸为内标,选择合适的共振峰,内标法定量标准物质的纯度,并对标准物质进行均匀性、稳定性检测和不确定度评估。[结果]质量平衡法的纯度定值结果为99.47%,定量核磁共振法定值结果为99.45%,最终所研制的DON纯度标准物质的纯度为99.5%,扩展不确定度为0.4%,均匀性良好,且满足12个月以上的稳定性要求。[结论]本试验所研制的DON纯度标准物质符合国家标准物质技术规范,目前已被批准为国家一级标准物质,并已被用于小麦、玉米等农产品实际检测过程中。

定量核磁共振波谱法快速测定灭火剂材料中全氟辛烷磺酰基化合物

泡沫灭火剂中全氟辛烷磺酰基化合物(PFOS)的使用受到严格管控.针对灭火剂中PFOS快速测定的需求,建立了基于19F的定量核磁共振波谱(qNMR)检测方法.方法以全氟丁基磺酸钾为标准物质,通过计算全氟丁基磺酸钾的-CF3在化学位移δ-78.94处19F特征峰和PFOS的-CF2在化学位移δ-117.12处19F特征峰的积分面积比值,进而实现PFOS定量分析.经测试,全氟丁基磺酸钾百分含量与定量峰面积线性相关系数为0.9955,检出限为0.024%,定量限为0.080%.8种灭火剂产品的定性测定结果与实际标注情况相吻合,其中4种泡沫灭火剂产品中PFOS含量在0.106%~1.339%之间.研究结果表明,方法受基质干扰小、检测速度快、灵敏度高,可为泡沫灭火剂中PFOS的管控提供可靠的检测方法与数据支撑.

俾路支褐煤有机结构特征及大分子模型构建

以巴基斯坦俾路支褐煤(BL)为研究对象,由元素分析得出BL化学式为C_(167)H_(130)O_(53)N_(2)S。经X射线光电子能谱(XPS)分析BL有机结构中氧、氮和硫元素存在形式。利用傅里叶变换红外光谱(FT-IR)研究BL有机结构中主要官能团特征,-CH和-CH^(2)为BL脂肪族结构中主要官能团。BL中苯环主要取代形式为三取代和四取代。运用核磁共振光谱(^(13)C-NMR)探究BL有机结构碳骨架结构。BL分子结构中,芳香桥碳与周碳之比X_(BP)为0.21,碳主要由芳香碳和脂肪碳2部分构成,其中脂肪碳质量分数53.23%,芳香碳占比41.93%。芳香结构以苯环和萘环为主,氧主要以羧基、羰基、醚氧和酚羟基形式存在,而氮主要以吡咯氮形式存在,硫主要为噻吩。建立BL二维分子结构模型,通过Materials Studio对其进行加氢饱和,构建BL分子模型三维立体结构,进一步优化所得分子模型,空间效果显著,得到能量最低的BL三维结构模型,发现范德华能是BL分子结构稳定的关键因素。通过计算得到的BL模型结构^(13)C NMR谱图与试验所测谱图基本一致,验证了所构建BL结构模型的合理性。

基于元素俘获谱测井和核磁共振测井的碳酸盐岩储层硅化作用类型判别

硅化作用在巴西桑托斯盆地A油田广泛发育,对储层物性有很大影响。在前人对该区硅化作用研究的基础上,以常规测井、元素俘获谱测井和核磁共振测井综合分析为主要手段,结合储层物性数据、X衍射数据和薄片等资料,将硅化作用成因类型进行了进一步细分,分析了不同硅化作用对储层物性的影响,总结出不同硅化作用的典型测井响应特征和判别方法。研究表明,不同硅化类型对储层物性影响不同,早成岩a型对储层物性的影响较小,早成岩b型和后热液b型储层物性随硅质含量的增加而变差,后热液a型储层物性变得极差,非该区域有效储层。在元素俘获谱测井定量计算地层硅质含量的基础上,综合分析常规测井和核磁共振测井曲线特征可以判别出碳酸盐岩储层硅化作用类型,该研究对其他相似地区进行硅化作用类型判别有借鉴意义。

台式小核磁共振波谱法测定聚乙烯密度

以密度梯度柱法测得的线型低密度聚乙烯(LLDPE)试样的密度为标准,建立了台式小核磁共振波谱法(简称小核磁法)测试LLDPE密度的标准曲线,分析了试样存放时间、恒温测试温度、存放温度对小核磁法准确度和重复性的影响。实验结果表明,存放时间60~120 d的LLDPE试样可用作标准试样;恒温温度分别为35.0℃和34.5℃时,小核磁法测得的密度与密度梯度柱法得到的密度较吻合。造粒后LLDPE立即在-23℃下冷冻后可用于建立标准曲线。利用标准曲线,对生产装置取出的试样立刻用小核磁法测试密度,结果满足重复性与准确度的要求。小核磁法测密度快速且可批量测试,节省人力和时间,维护简单,健康环保。利用LLDPE粒料存放时间与小核磁法密度的关系表,可通过小核磁法快速准确测定已知生产时间的LLDPE的密度。

冬虫夏草成分分析技术进展

综述了冬虫夏草成分分析技术进展。冬虫夏草成分分析技术主要包括色谱及其联用技术、光谱技术、核磁共振波谱技术等。色谱及其联用技术操作简单、分离效果好、效率高、易于自动化,广泛用于冬虫夏草核苷类、多糖类和甾醇类等成分的分离分析中;光谱技术分析速度快,检出限低、灵敏度高,能够精准实现冬虫夏草多糖类、氨基酸和重金属的定性定量分析;核磁共振波谱技术常用于辨别复杂混合物的化学性质,具有高重现性、非选择性、非破坏性等特点,能对冬虫夏草多种成分进行同步分析。提高冬虫夏草成分分析灵敏度与精确度,降低其检出限,研发出更多的新型分析技术与多技术联用将会是未来发展的重点方向。

高温高压降解制备低分子量水溶性酵母葡聚糖

以啤酒酵母粉为原料,利用硫酸苯酚法和高效凝胶排阻色谱法,分析在压力为0.1MPa时不同温度条件下降解得到的水溶性酵母葡聚糖的得率和分子量,并利用傅里叶变换红外光谱和核磁共振波谱技术,分析不同降解条件下水溶性酵母葡聚糖结构的变化。研究结果表明,120℃条件下水溶性酵母葡聚糖得率低于20%。而温度升高到135℃,pH值在3~5之间可以使水溶性酵母葡聚糖得率升高到60%~80%。pH值越低,水解时间越长,制备出水溶性酵母葡聚糖和葡寡糖得率越高。135℃、pH3降解3.0~6.0 h,主要得到葡寡糖,得率可达79.89%;pH4降解4.0~6.0 h、pH5降解6.0 h,主要得到12~100 kDa的水溶性酵母葡聚糖。傅里叶变换红外光谱和核磁共振波谱结果发现,高温高压降解后该葡聚糖仍以β-(1,3)为主链,以β-(1,6)为支链。但是pH值越低,β-(1,6)支链含量越低,pH3时β-(1,6)/β-(1,3)积分最低,为0.61。因此,通过控制降解的pH值、温度和时间,高温高压降解法可以有效制备不同分子量的水溶性酵母葡聚糖和葡寡糖。

蔗渣生物炭对岩溶峰丛洼地石灰土土-水特征曲线的影响

岩溶地区岩石裸露、土壤浅薄且持水能力较低,其土壤水分保持和运动状况是其水土漏失治理的重要因素。生物炭拥有多孔结构和高比表面积,能改变土壤持水能力,但其种类、粒径、添加量和土壤类型等因素对土壤持水能力产生正面或负面作用,为了研究添加不同比例蔗渣生物炭对岩溶峰丛洼地石灰土持水特性的影响,选取位于广西河池地区岩溶峰丛洼地的石灰土壤作为试验样本,分别添加不同比例生物炭(0%,2%,4%,6%),利用滤纸法测定生物炭-石灰土混合土在0~40MPa吸附能力下土水特性曲线,并使用扫描电子显微镜(SEM)和核磁共振波谱法(NMR),观察生物炭-石灰土混合土的微观孔隙结构。研究结果表明:当土壤含水量超过30%时,不同比例生物炭掺入量的持水能力相似,土壤的持水性并不会随着生物炭掺入量的增加而持续提升。在添加生物炭0%,2%,4%时混合土的持水能力是在逐渐提高的,添加4%和6%时混合土的持水能力基本一致,这表明添加生物炭存在一个最优值和适用范围。建议岩溶峰丛地区石灰土含水率在30%以下时,施加4%~6%的蔗渣生物炭,可提高土壤的持水能力。