Effect of Acid Elution on the Surface Structure Characteristics and Spectral Characteristics of Biochars.

Biochar often refers to a carbon-rich product obtained by pyrolyzing biomass at relatively low temperatures (<700 ℃). The increasing interest in the applications of biochar in soil amendment and environmental contaminant reduction has spurred many studies in recent years. Due to the high content of ash in biochar, the adsorption capacity of bichar is limited. The ash of biochar formed during pyrolysis has great influence on the structure characteristics and spectral characteristics of biochar. The ash of biochar is expected to enchance their efficacy and minimize their influence. For this purpose, the corn straw biochar made at two different temperatures (400 and 600 ℃) was used to study the effect on the structure characteristics of biochars under the acid elution. The samples were characterized with element analysis, Brunaner-Emmett-Teller-N2 surface areas, pore size distributions and micro infrared for structure analysis in this study. The result indicate that: the elution solvent could remove the by-products and improve the adsorptive capacity of biochars. (1)After acid elution, the carbon content, hydrophobicity and the aromatic functional group content were increased; the polarity of biochar was decreased. (2) After acid treated, the specific surface area of the biochars was significantly increased, the increment of two biochars was 3.46 times and 6.75 times; the pore volume and the mesoporous quantity were also enhanced. (3) After acid elution, the infrared analysis is similar, but the content of key functional groups was different significantly. The result of infrared analysis showed that, several absorbance peaks were decrease at 3 398~3 447, 2 924~3 056, 1 378~1 439 cm-1, and the acid treated can make the content of aliphatic chain char and hydroxyl reduce. (4) Biochar with low polarity and high aromaticity displayed a superior 2,4- dichlorophenoxyacetic acid adsorption capacity. Acid elution made the surface of biochar exposed more organic surface and porosity and it is one of the most important factors for the adsorption of biochar. The date with elemental analyzer, BET，FTIR techniques and batch experiment allowed us to develop a better understanding of evolution of biochar properties during the acid elution and these results have significant implications for using biochar as a soil additive for soil pollution.

[Effects of different fertilization treatments on soil humic acid structure characteristics].

The present article used soil humic acid as research object to study effects on the structure characteristics of soil humic acid under the condition of applying cake fertilizer, green manure, straw fertilizer with the same contents of nitrogen and phosphorus. It used element analysis, micro infrared, and solid 13C-NMR for structure analysis, the results indicated that: The chemical composition and structure characteristics of humic acids were similar, but they also had many obvious differences. (1) The atomic ratios of H/C, O/C, and C/N were all different for the humic acids, the soil humic acid of cake fertilizer processing had the highest contents of H and N, green manure processing of soil humic acid contained the highest content of O, while straw fertilizer processing of soil humic acid contained highest content of C. (2) Infrared analysis displayed that the three soil humic acids contained protein Cake fertilizer processing of soil humic acid contained the most amino compounds, green manure processing of soil humic acid contained the maximum contents of hydroxyl and aliphatic hydrocarbon, while straw fertilizer processing of soil humic acid contained the highest contents of alcohol and phenol. (3) Solid 13C-NMR data indicated that cake fertilizer processing of soil humic acid contained the most carboxyl carbon, green manure processing of soil humic acid contained the highest contents of alkyl carbon and carbonyl carbon, while straw fertilizer processing of soil humic acids had the most alkoxy carbon and aromatic carbon

The efficacy and safety of melatonin in concurrent chemotherapy or radiotherapy for solid tumors: a meta-analysis of randomized controlled trials.

BACKGROUND: Recently, melatonin has been associated with cancer both in vitro and in vivo. However, the value of melatonin in the treatment of cancer remains disputable. Hence, we performed a systematic review of randomized controlled trials (RCTs) of melatonin in solid tumor cancer patients and observed its effect on tumor remission, 1-year survival, and side effects due to radiochemotherapy. METHODS: An electronic search was conducted using the databases Pubmed, Medline, EMBASE, Cochrane library, and CNKI, from inception to November 2011. Trials using melatonin as adjunct treatment concurrent with chemotherapy or radiotherapy for cancer were included. Pooled relative risk (RR) for the tumor remission, 1-year survival, and radiochemotherapy-related side effects were calculated using the software Revman 5.0. RESULTS: The search strategy identified 8 eligible RCTs (n = 761), all of which studied solid tumor cancers. The dosage of melatonin used in the 8 included RCTs was 20 mg orally, once a day. Melatonin significantly improved the complete and partial remission (16.5 vs. 32.6%; RR = 1.95, 95% CI, 1.49-2.54; P < 0.00001) as well as 1-year survival rate (28.4 vs. 52.2%; RR = 1.90; 95% CI, 1.28-2.83; P = 0.001), and dramatically decreased radiochemotherapy-related side effects including thrombocytopenia (19.7 vs. 2.2%; RR = 0.13; 95% CI, 0.06-0.28; P < 0.00001), neurotoxicity (15.2 vs. 2.5%; RR = 0.19; 95% CI, 0.09-0.40; P < 0.0001), and fatigue (49.1 vs. 17.2%; RR = 0.37; 95% CI, 0.28-0.48; P < 0.00001). Effects were consistent across different types of cancer. No severe adverse events were reported. CONCLUSIONS: Melatonin as an adjuvant therapy for cancer led to substantial improvements in tumor remission, 1-year survival, and alleviation of radiochemotherapy-related side effects.

[Adsorption characteristics and mechanism of atrazine on three types of humic acid].

This study mainly researched the adsorption properties and adsorption mechanism of atrazine on three different types of humic acids: the black soil humic acid, the chestnut soil humic acid and the humic acid purchased. After the extraction of humic acid from the two different types of soil, the black soil and chestnut soil, adsorption experiments were carried out using the batch equilibrium techniques. Then FTIR and ESR spectral analysis methods were employed to explain the functional mechanism between atrazine and humic acid. The results showed that the sorption of humic acid on atazine was very fast at the beginning, then went to slower and finally came to equilibrium. The relationship between the amount of atrazine sorbed by the three humic acids and reaction time all fitted logarithmic and hyperbolic equations well. Adsorption isotherms of atrazine on the three humic acids all are L-type and in accordance with the linear model and the Freundlich model. Because of the different structure, there is significant difference between the adsorption isotherm of atrazine on purchased humic acid and extract humic acid. The interactions between humic acid and atrazine are mostly weak forces, such as the H-bond, proton transfer, charge transfer, van der Waals force and so on. In addition, ESR analysis proved that charge transfer exists between humic acid and atrazine during the process of adsorption.

[Effect of different tillage managements on black humic fractions and IR spectral feature].

The present study was based on the long-term (10 years) field conservation tillage experiment, in which four tillage treatments were designed as following: Conventional tillage (CT) by moldboard plowing with ridge culture; Rotary tillage with ridge culture (RT); Alternant tillage by rotary on wide row and loosing on narrow row (WN); Rotary tillage plus deep loosing annually (RD). Humic acids were extracted from black soil profiles under these tillage managements. The elements visible spectra and FTIR of HA in black soil were analyzed. The results indicated that the elements of HA were affected by different tillage managements, WN increased N/C, H/C and O/C values of HA in the 0-20 cm layer. The lowest E4/E6 value of HA was found under CT treatment, while the highest E4/E6 value was found under WN treatment; FTIR indicated that CT treatment increased the amount of C=N groups and aromatic ring condensation of HA in 0-20 cm soil, while WN decreased aromatic ring condensation and increased the content of nitrogen compound and aliphatic compound. RT increased the functional groups of OH, aliphatic CH2 and nitrogen compound. CT and RD increased the content of C=O and C-O.

[Effects of different managements on soil humic acid structural features in chestnut soil on typical Leymus chinensis steppe, Inner Mongolia, China].

Grazing has a lot of effects on grassland soil properties. The objective of the present study is to investigate the effects of different managements on soil humic acids. Soil samples were collected from the surface soil of four adjacent plots ( I , II , III and IV) at a long-term experiment site of the Inner Mongolia Grassland Ecosystem Research Station (IMGERS), the Chinese Academy of Sciences. The structure features of humic acids were investigated by cross-polarization magic angle spinning 13C-nuclear magnetic resonance spectroscopy (CP/MAS 13C-NMR), FTIR and elemental analysis. The results indicated that the humic acid extracted from the grazing plots were characterized by a higher degree of humification, including loss of polysaccharides, decrease in lignin content and increase in aromaticity. Compared with the humic substances from the grazing plots, the humic substances from fenced plots showed a lower degree of humification and were considerably more aliphatic in nature.

[Adsorption characteristics and mechanism of 2,4-D on two types of humic acid].

This study mainly focused on the adsorption properties and adsorption mechanism of 2,4-D on two different humic acids. After the extraction of humic acid from the two different types of soil, the black soil and chestnut soil, adsorption experiments were carried out using the batch equilibrium techniques. Then FTIR and ESR spectral analysis methods were employed to explain the functional mechanism between 2,4-D and humic acid. The results showed the relationship between the amount of 2, 4-D sorbed by the two humic acids and the reaction time, with the adsorption process for both acids being very fast at the beginning, then becoming slower and finally reaching equilibrium. The adsorption capacity of 2, 4-D on black soil humic acid and chestnut soil humic acid were 0.39 and 0.42 mg x kg(-1) respectively. More carboxylic acid structure made the initial adsorption rate of 2,4-D on black soil humic acid much faster than on chestnut soil humic acid. Adsorption isotherm of 2,4-D on the two humic acids was both in accordance with the linear model and the Freundlich model. The interactions between humic acid and 2,4-D are mostly weak forces, such as the H-bond, proton transfer, charge transfer, van der Waals force and so on. In addition, ESR analysis found that covalent bond exists between humic acid and 2,4-D or its degradation product during the process of adsorption.

[Comparison of various spatial interpolation methods for non-stationary regional soil mercury content].

Accurate delineating of the spatial distribution of soil heavy metal content is essential for pollution assessment and remediation. The objective of this paper is to evaluate various spatial interpolation methods, including ordinary Kriging (OK), simple Kriging (SK), lognormal Kriging (LNK), universal Kriging (UK), disjunctive Kriging (DK) and inverse distance weighting interpolation (IDW) for estimating soil surface Hg content with lognormal distribution, the linear and second-order polynomial trend, and to determine the optimal interpolation method. The predicted errors, statistical feature values and prediction maps obtained by different interpolation methods were compared. The result indicated that first-order trend OK method performed better than both zero and second-order OK methods. Within the method of first-order trend OK, Gaussian semi-variogram model performed better than both the spherical and exponential models. The method using transformed data performed worse than the methods without data transformation because of the 'distortion' effect arising from log transformation. Those with trend effect were better than those without trend effect. First-order trend UK method is the best method among the six methods studied, while the IDW method is the least.