[Temporal and Spatial Distribution, Utilization Status, and Carbon Emission Reduction Potential of Straw Resources in China].

Based on the crop yield data of China and each region from 1981 to 2020 (excluding data from Hong Kong, Macao, and Taiwan), by using the grain-straw ratio method, this study estimated the total amount of crop straw and collectable amount of crops, including corn, rice, wheat, other cereals, cotton, rapeseeds, peanuts, beans, tubers, sesame, fiber crops, sugarcane, and beetroots, and the spatial and temporal distribution characteristics of resource density and per capita resources of crop straw were analyzed. This study analyzed the current utilization mode, development, and change of crop straw in China. Finally, we used the life circle assessment (LCA) method to estimate the carbon emission reduction potential of biochar prepared from crop straw. The main findings were:from 1981 to 2020, the temporal distribution trend of theoretical crop straw resources and collectable straw resources in China generally showed a steady growth trend, and the two increased from 3.33×108 t and 3.04×108 t in 1981 to the highest values of 7.70×108 t and 6.63×108 t in 2020, with a net increase of 4.37×108 t and 3.59×108 t, respectively. The net increase in rice, wheat, and corn straw resources was 3.69×108t, accounting for between 77% and 85% of the total crop straw and always occupying the main position of straw resources in China. The proportion of wheat straw in the total amount of straw was maintained at approximately 20%, rice straw resources decreased from 44% to 28.4%, and corn straw increased from 19.9% to 34.2% from 1981 to 2020. In 2020, the total theoretical resources of crop straw in China were 7.72×108 t, and the source structures were:rice 28.4%, wheat 21.45%, corn 31.45%, other cereals 1.4%, beans 3.4%, tubers 0.82%, cotton 2.28%, peanuts 2.97%, rapeseeds 3.4%, sesame 0.12%, fiber crops 0.06%, beetroots 0.67%, and sugarcane 0.84%. As to the spatial distribution of crop straw resources in China in 2020, the locations with straw resources ≥ 60 million tons included Heilongjiang, Henan, and Shandong, of which Henan had as much as 88.56 million tons; those with between 40 million and 60 million tons included Hebei, Inner Mongolia, Jiangsu, and Anhui; those with between 20 million and 40 million tons included Liaoning, Jilin, Jiangxi, Hubei, Hunan, Sichuan, Yunnan, and Xinjiang; and the straw resources in the rest of the region were below 20 million tons. Rice straw was mostly distributed in the middle and lower reaches of the Yangtze River and the Northeast region, of which the amount of Heilongjiang rice straw was the largest, with 31.86 million tons; wheat straw was mainly distributed in North China, with Henan having the most abundant resources (48.04 million tons). Corn straw was mainly distributed in Northeast China and North China, of which Heilongjiang and Inner Mongolia corn straw resources were relatively rich, with 33.18 million tons and 29.90 million tons, respectively. Crop straw resource density and per capita resources were shared in 2020 in China. The average density of crop straw resources in China was 4.61 t·hm-2, and the average densities of crop straw resources in various agricultural areas were 5.39 t·hm-2 in Northeast China, 5.42 t·hm-2 in North China, 4.45 t·hm-2 in the Mengxin Region, 4.44 t·hm-2 in the middle and lower reaches of the Yangtze River, 3.92 t·hm-2in Tibet, 3.40 t·hm-2 in the Loess Plateau, 3.08 t·hm-2 in South China, and 2.91 t·hm-2 in Southwest China. The average per capita share of straw resources was 0.55 t. The average values of per capita straw resources in each region were:1.46 t in the Northeast area, 1.20 t in the Mengxin Region, 0.47 t in North China, 0.44 t in the middle and lower reaches of the Yangtze River, 0.40 t in the Loess Plateau, 0.37 t in the Southwest area, 0.33 t in the Qinghai-Tibet area, and 0.20 t in the South China area. The utilization of crop straw in China was diversified. Fertilizer and feed were the main utilizations, accounting for 62.1% and 15.4%, respectively. In 2020, collectable crop straw resources for the preparation of biochar totaled 2.04×108 t in China. Renewable energy replaced fossil fuels in the process of preparing biochar, which could reduce CO2e(CO2e:CO2 equivalent) emissions by 1.45×108 t. Biochar could sequester approximately 4.63×108 t of CO2e; biochar application was able to reduce chemical fertilizer application to achieve a CO2 emission reduction of 8.58×105 t; and biochar application could promote crop yield in order to reduce CO2e emissions by approximately 7.77×106 t. The inhibition of N2, respectively. In the process of biochar preparation and application, the total greenhouse gas emission was 3.32×107 t, and the net greenhouse effect emission reduction reached 5.86×108 t, i.e., it could sequester 0.88 t CO2e per ton of raw materials. The net greenhouse gas emission reduction of unused straw was 6.73×107 t in 2020. With the continuous harvest of grain crops in China, the potential of biochar preparation and carbon sequestration will increase yearly. Using crop straw to prepare biochar has great potential and will be one of the most effective ways to achieve carbon emission reduction in agriculture. It is suggested that government departments should pay attention to the preparation of biochar, support the field experiments of biochar application effects after applying soil on policy and funds, and then introduce relevant biochar standards to ensure the scientific application of biochar prepared by crop straw according to local conditions, so as to achieve the dual benefits of carbon emission reduction and soil remediation and yield increase.

[Effect of Ca-bentonite on Cu and Zn Forms in Compost and Soil, and Their Absorption by Chinese Cabbage].

Aerobic composting was conducted to evaluate the effects of the different ratios (0%, 2.5%, 5%, 7.5%, and 10%) of Ca-bentonite (CB) on the speciation of Cu and Zn during pig manure composting, while pot experiment was performed to investigate the role of CB-added compost on the bio-availability of Cu and Zn to Chinese cabbage and its biomass. The results showed that the exchangeable fractions of Cu and Zn decreased, while their oxidized and residual fractions gradually increased during composting; CB addition reduced the distribution ratios of bio-available Cu and Zn in mature compost by approximately 19.84%-48.90% and 4.94%-16.39%, compared to those in the 0% CB-added treatment, and the best result was found in the 10% CB-added treatment.. Meanwhile, the pot experiment confirmed that the addition of compost considerably increased soil organic matter (OM) and electrical conductivity (EC) but decreased soil pH value. On the contrary, the application of CB effectively decreased EC and increased soil pH but inhibited OM mineralization in soil as compared to non-amended treatment. While addition of compost significantly increased plant dry biomass as compared to that with soil alone, maximum biomass was obtained[(6.51±0.34) g·pot-1] in 10% CB-added compost. After the application of CB-added compost, the contents of the bio-available factions of Cu in the harvested soil increased, while the contents of the exchangeable fractions of Zn decreased by 38.91%, 43.69%, 46.02%, 45.12%, and 54.65%, respectively. The absorption of Cu and Zn by Chinese cabbage was considerably reduced after the application of compost, while the uptake of Zn in the plant declined as the CB rates increased, and the absorption of Cu increased. The study indicated that 10% CB addition could significantly reduce the bioavailability of Cu and Zn in compost, and also showed a continuous effect on restricting the bioavailability of Zn after land utilization. Meanwhile CB amendment enhanced Chinese cabbage biomass and reduced the uptake of Zn.

[Effects of Bentonite Amendment on Detoxification, Heavy Metal Passivation and Estrone Elimination of Sewage Sludge Compost].

Sewage sludge was amended with calcium-based bentonite with addition of no more than 10% in dry weight during the 52-day aerobic composting process, the variations of temperature, pH, organic carbon, EC, total nitrogen, nitrate(NH4+-N) and ammonium(NO3--N) were investigated, as well as the compost detoxification(germination test), heavy metals(Zn, Cu, Pb, Cd) passivation and estrone(E1) elimination. The results showed that the amendment facilitated the thermophilic phase, promoted the compost heat inactivation and brought the organic carbon mineral up to more than 15.27% -19.71%. During the composting, the compost pH increased at the beginning and then gradually decreased before reaching values of 6.76-7.05, while the amendments alleviated the dramatic pH value fluctuation. The bentonite amendment reduced the salinity of the compost with final product EC remarkably lower than 1132 µS·cm-1 of the control treatment, and the effect was enhanced with the increase of addition amount. The total nitrogen content increased with time, and there was a remarkable ammonia loss in the beginning stage for the control treatment, while the bentonite addition could facilitate the total nitrogen content increase by reducing the ammonia loss. With the composting variation, the contents of NH4+-N increased and then decreased while the NO3--N content increased gradually. The bentonite addition had a slight inhibitory effect on the plant germination but did not influence the compost maturity and detoxification; meanwhile, the amendment improved the heavy metal passivation and reduced the E1 content, especially from 90.48 to 28.27 µg·kg-1 with 5% treatment during the composting. The study indicated that bentonite addition of lower than 5% was acceptable for the sludge compost amendment, which had great potential in sludge hygienization, detoxification, heavy metal passivation and E1 elimination.

[Cd(â ¡) Ion Adsorption and Sealing onto SBA-15 Mesoporous Particles and the Related Potential on Cd(â ¡) Polluted Soil Remediation].

Aiming to expand the utilization of porous silicate minerals in the remediation of heavy metal contaminated soil,the mesoporous material SBA-15 was successfully synthesized by using sodium silicate as silica source in this study.And the obtained SBA-15 samples were characterized by TEM,X-ray diffraction,N2 adsorption-desorption and FTIR.Furthermore,characterization of Cd (Ⅱ) adsorption and sealing performance onto SBA-15 were evaluated through batch experiment,and the remediation potential of Cd (Ⅱ) contaminated soil was investigated by brassica planting in a pot experiment.The results showed that SBA-15 had the mesoporous structure with surface area of 507.3 m2·g-1 and pore size of 7.38 nm.The maximum Cd (Ⅱ) adsorption capacity was 76.43 mg·g-1 at pH above 7.0 with the adsorption isotherm fitting the Langmuir model in the solution of 100 mg·L-1 Cd (Ⅱ).The increase in ionic strength reduced the Cd (Ⅱ) adsorption capacity.The Cd (Ⅱ) loaded SBA-15 could be regenerated with 0.1 mol·L-1 HNO3,while Cd (Ⅱ) could be strongly sealed in the pore structure after introduction of sodium silicate into the system.The pot experiment proved that the addition of SBA-15(4.5 g·kg-1) into Cd-contaminated soil could reduce Cd (Ⅱ) availability,enhance the transformation of soluble and exchangeable Cd (Ⅱ) fractions into carbonate and Fe-Mn oxides bounded forms,inhibit the Cd (Ⅱ) accumulation in the plant tissue and improve the brassica growth.Based on these results,it can be concluded that combination of the SBA-15 particle with sodium silicate has great potential to remediate Cd (Ⅱ) contaminated soil through adsorption and sealing properties.

[Application Potential and Assessment of Metallurgical Contaminated Soil After Remediation in Tongguan of Shaanxi].

There has been a growing interest in soil replacement and in-situ stabilization techniques in recent years. Many techniques in the remediation of contaminated soils have been proven to be effective methods. In this study, lime and calcium phosphate were added to immobilize the heavy metals in contaminated soils. The long-term application potential of these techniques were evaluated by taking the demonstration project of the soil remediation in Tongguan of Shaanxi as the case study.The status of heavy metal contamination in the study area resulted from artisanal gold mining was discussed. The strategies of remediation and the evaluation of the remediation results including the safety of agricultural practices were also studied. The results showed that soil was seriously contaminated in the study area with Cd, Pb, and Hg, and the residue mining waste was the main source. The potential ecological risk index ranged from 668 to 10969, suggesting that all the samples posed a very strong ecological hazard. Based on the pollution status, the soil replacement method and stabilization method were applied. Acceptable remediation results were obtained with lower total metal content (except Cd) and decreased heavy metal availability. However, the metal content of agricultural products was higher than the permissible value according to GB 2762-2012, which means that agricultural practices pose risks on remediated soils. Soil replacement and stabilization would be practical techniques for heavy metal polluted soil remediation. However, a consecutive investigation should be conducted for the assurance of food safety.

[Adsorption Cd2+ from Solution by EDTA-modified Silicate Nanoparticles].

Silicate nanoparticles(nSiO2) are a kind of widely used engineering material. In order to improve the Cd2+ adsorption ability, the EDTA-modified nSiO2 nanoparticles were prepared by grafting method and characterized by TEM, N2 adsorption-desorption, FTIR, and TGA. The effects of solution pH, contact time, temperature and ionic strength were examined. The adsorption mechanism was further investigated by XPS. The results showed that the EDTA-nSiO2 nanoparticles possessed excellent stability, and were successfully prepared. Cd2+ adsorption was mainly controlled by solution pH. The raw nSiO2 had limited Cd2+ adsorption ability, while the EDTA-modified nSiO2 particles had significantly improved adsorption performance. At high pH, the Cd2+ adsorption rate increased and kept balance above pH 4.0. The Cd2+ adsorption was an endothermic spontaneous process which could be finished within 1 h. Langmuir model could be used to describe the adsorption isotherm. The temperature ranged from 293-313 K during the process, while the maximum adsorption was observed at higher temperature. Higher ionic strength could inhibit the Cd2+ adsorption. The Cd2+ adsorption decreased from 0.433 to 0.294 mmol·g-1, when NaCl concentration varied from 0 to 100 mmol·L-1. The desorption of Cd2+ from the EDTA-nSiO2 nanoparticles was carried out with distilled water, 0.1 mol·L-1 NaCl and 0.1 mol·L-1 HCl. The maximum Cd2+ desorption of 94.36% was obtained at 0.1 mol·L-1 HCl. Based on the results of thermodynamics, pH, ionic strength, and XPS analysis, it could be concluded that Cd2+ adsorption was a multiple process dominated by chemical chelating reaction, physical adsorption and ion exchange. This study indicated that the EDTA-nSiO2 is an effective engineering nanomaterial that could be used in Cd2+ adsorption.

[Effect of Alkali Solids Amendment on Sewage Sludge Aerobic Composting and the Potential of Related Products on Infertile Soil Amelioration].

Aiming to evaluate the influence of alkali solids amendment on the sewage sludge aerobic composting and to declare the potential of related composts on infertile soil amelioration, sewage sludge and sawdust mixture were amended with straw biochar, hardwood biochar, fly ash and lime by 10% addition ratio in dry weight during the aerobic composting process; finally, potential of the related composts on the infertile soil amelioration was investigated by pot experiment. The results showed that the alkali solids amendment could prolong the thermophilic phase, and promote the composting material heat inactivation. Addition of straw and hardwood biochar facilitated more than 21.65% and 18.16% organic matter degradation. During the composting, the compost pH decreased at the beginning and then gradually increased before reached values of 6.78-7.33, while the fly ash and lime amendments could lead to higher pH values in the beginning stage. The alkali solids amendment reduced the salinity of the compost with final products EC lower than 3000 µS·cm-1. The addition of straw and hardwood biochar could increase the total nitrogen content by reducing the ammonia loss at the beginning, while the fly ash and lime amendments would result in ammonia loss in the beginning stage. Despite the composting variation, the contents of nitrate increased and the ammonium salt content decreased gradually. The biochar addition can accelerate the nitrate transformation while the fly ash and lime amendment had slight inhibitory effect on the nitrate transformation and plant germination. The pot experiment revealed that applying compost products could significantly improve the brassica growth, Cu and Zn micronutrients accumulation since the compost addition could increase the soil organic carbon content, as well as soil N, P, and K contents. Compared with the non-amended compost, the alkali solids amendment could slightly reduce the Cu and Zn micronutrients accumulation, while the fertile potentials were acceptable. The study indicated that straw and hardwood biochar were more suitable than fly ash and lime as compost amendment, and the related compost products had great potential on infertile soil amelioration.

[Suprapubis-assisted umbilical laparoendoscopic mini-dual-site surgery for varicocele: a report of 80 cases].

OBJECTIVE: To study the safety, effectiveness and feasibility of suprapubis-assisted umbilical laparoendoscopic mini-dual-site surgery (SAU-LEMDS) in the treatment of varicocele. METHODS: This study included 80 varicocele patients aged 24 - 44 (mean 28.5 +/- 2.6) years, 25 cases of grade I, 45 cases of grade II and 10 cases of grade III, 58 cases in the left side, 6 in the right and 16 in both sides, and all with asthenospermia. The patients were treated by SAU-LEMDS under subarachnoid anesthesia combined with general anesthesia in a supine position with a head-down-feet-up slope of 15 degrees. Two 5 mm trocars were inserted bilaterally at the umbilical edge, one with a 5 mm 30 degrees laparoscope placed in it, and another into the abdominal cavity below the pubic hairline with a 5 mm laparoendoscopic clipper placed in it. The operation procedure was similar to that of standard laparoscopic ligation of spermatic veins, with reservation of the spermatic artery and double-ligation of spermatic veins. And the procedure was repeated for the contralateral lesion in the bilateral cases. Postoperative follow-up was conducted for the incidences of orchiatrophy and testicular hydrocele and changes of seminal parameters. RESULTS: All the operations were successful, with the mean operation time of (10 +/- 5.0) min (range 8 to 25 min) for the unilateral cases and (18 +/- 6.5) min (range 15 to 30 min) for the bilateral cases, the mean blood loss of (1.5 +/- 0.5) ml (range 1 to 2 ml), and the mean postoperative hospital stay of (2 +/- 0.5) d (range 1.5 to 3 d). The patients were followed up for 6 -24 (12 +/- 2.5) months, which showed significant improvement in sperm motility as compared with the baseline ([28.53 +/- 5.21] vs [19.62 +/- 3.56]%, P < 0.05), with 28 cases (35.0%) restored to normal. Recurrence was found in 4 cases (5.0%). Testicular hydrocele occurred in 7 cases (8.75%), but orchiatrophy in none. The scars in the umbilicus and suprapubis were invisible because of the wrinkles and pubic hair. CONCLUSION: SAU-LEMDS is safe, effective and feasible for the treatment of varicocele. It is superior to umbilical laparoendoscopic single-site surgery (U-LESS) for its less invasiveness, simpler operation, and better cosmetic appearance.

[Adsorption of Cd2+ ions in aqueous by diamine-modified ordered mesoporous SBA-15 particles].

Highly ordered channel structure SBA-15 was widely concerned as new adsorbents in environmental protection, in order to increase its heavy metal ions adsorption ability from aqueous solution, the diamine -modified porous silicate SBA-15 was synthesized by a hydrothermal grafting method and characterized by TEM, X-ray diffraction, FTIR and N2 adsorption-desorption. The SBA-15 and modified SBA-15 samples were used as sorbents to adsorb Cd(II) ions from aqueous solution. The effect of experimental parameters, such as pH, contact time, sorbent dosage and temperature were examined, and the maximum adsorption amount was also calculated. The results showed that under same conditions, the Cd(II) removal rate was higher for 2N-SBA-15 than that of the unmodified SBA-15. The adsorption process was controlled by system pH. The highest removal rate could reached about 95% after pH was higher than 4. Adsorption equilibrium was reached within 30 minutes,and more than 95% Cd2+ was adsorbed when 7.5-20 mg sorbent was added into 100 mL solution contained 25 mg x L(-1) Cd2+. The adsorption capacity increased from 94.73% to 98.22% with temperature increased from 25 degrees C to 35 degrees C. The Langmuir model can be used to describe adsorption isotherms. The adsorption capacity of Cd2+ was 0.9 mmol x g(-1) which is comparable to the adsorption capacity of various adsorbents reported in the literature, and 0.1 mol x L(-1) HCl could remove nearly 93% Cd2+ from 2N-SBA-15 particles. Based on the thermodynamic, pH, XPS and Zeta potential analysis results in this study, it could be concluded that the adsorption process was an endothermic and spontaneous reaction which contained physical adsorption, ion exchange and chelating reaction etc. The study indicated that the diamine -modified ordered mesoporous material SBA-15 is a potential sorbent which could be used for the aqueous Cd2+ removal.

[A study on the neuronal mechanism of retrieval of long-term digital memory in human by functional magnetic resonance imaging].

To investigate the neuronal mechanism of retrieval of long-term digital memory in healthy volunteers, functional magnetic resonance imaging (fMRI) technique was used in the study. Twenty-two right-handed volunteers were subjected to a long-term digital memory test with block-design. The memory task and control task were adopted in the experiment alternatively. The fMRI data were recorded by a Siemens 1.5T MR machine and analyzed by SPM99. The activated brain regions were shown in the Talairach coordinate. The results showed that the Brodmann's area (BA) 9 region in left middle frontal gyrus was the most activated cortex during the long-term digital memory task. The left medial frontal gyrus, left inferior frontal gyrus, right inferior frontal gyrus, cingulate gyrus, left inferior parietal lobule, left superior parietal lobule, right superior parietal lobule, right middle temporal gyrus, left lingual gyrus, left middle occipital gyrus, right middle brain, cerebellum and right caudate nucleus tail were also involved. The activation in cortices showed obvious left predominance. It is suggested that a series of brain regions with left predominance are involved in long-term digital memory. Left lateral frontal cortex would be the most important structure for information extraction, while the other cortices and their connections may be important for processing and long-term storage of digital information.

Preparation of a carbon-based solid acid catalyst by sulfonating activated carbon in a chemical reduction process.

Sulfonated (SO(3)H-bearing) activated carbon (AC-SO(3)H) was synthesized by an aryl diazonium salt reduction process. The obtained material had a SO(3)H density of 0.64 mmol·g-1 and a specific surface area of 602 m2·g-1. The catalytic properties of AC-SO(3)H were compared with that of two commercial solid acid catalysts, Nafion NR50 and Amberlyst-15. In a 10-h esterification reaction of acetic acid with ethanol, the acid conversion with AC-SO(3)H (78%) was lower than that of Amberlyst-15 (86%), which could be attributed to the fact that the SO(3)H density of the sulfonated carbon was lower than that of Amberlyst-15 (4.60 mmol·g-1). However, AC-SO(3)H exhibited comparable and even much higher catalytic activities than the commercial catalysts in the esterification of aliphatic acids with longer carbon chains such as hexanoic acid and decanoic acid, which may be due to the large specific surface area and mesoporous structures of the activated carbon. The disadvantage of AC-SO(3)H is the leaching of SO(3)H group during the reactions.

Cognitive stimulation therapy in the treatment of neuropsychiatric symptoms in Alzheimer's disease: a randomized controlled trial.

OBJECTIVE: to determine the efficacy of cognitive stimulation therapy (CST) in the treatment of neuropsychiatric symptoms in patients with Alzheimer's disease. DESIGN: a randomized, controlled, rater-blind clinical trial. SETTING: the military sanatorium. SUBJECTS: thirty-two patients with mild to moderate Alzheimer's disease exhibiting marked neuropsychiatric symptoms were included in the study. INTERVENTION: all 32 patients were randomly assigned to a cognitive stimulation therapy group (n = 16) or a control group (n = 16) for 10 weeks. MAIN MEASURE: the efficacy measures included the Mini Mental State Examination and the Neuropsychiatric Inventory. RESULTS: patients receiving cognitive stimulation therapy showed a greater improvement in the Neuropsychiatric Inventory total score (mean change - 2.06 points versus 0.00 points, t = -4.766, P<0.001) and in the Mini Mental State Examination total score (mean change 0.81 points versus -0.19 points, t =3.106, P =0.004) compared to control at week 10. Analysis of the individual Neuropsychiatric Inventory domains revealed a statistically significant benefit for cognitive stimulation therapy-treated patients in the areas of apathy (mean change -1.06 points versus -0.31 points, P =0.017) and depression/dysphoria (mean change -0.50 points versus 0.06 points, P =0.047). There were no statistically significant benefits for cognitive stimulation therapy-treated patients in the other individual Neuropsychiatric Inventory domains or in the caregiver distress score. CONCLUSIONS: cognitive stimulation therapy has significant efficacy in lowering apathy and depression symptomatology and in the Mini Mental State Examination in patients with mild to moderate Alzheimer's disease.

[Physical and chemical properties of land-filling pile and aged refuse in 5-year-old semi-aerobic and anaerobic landfills].

This paper studied the surface settlement, temperature, and gas production of land-filling pile, and the physical and chemical properties of aged refuse in 5-year-old semi-aerobic and anaerobic landfills. The pile's surface settlement and its volume reduction rate were significantly higher in semi-aerobic than in anaerobic landfill; and the treatment with leachate recycling brought larger uneven settlement than the treatment with water recycling. The temperature of anaerobic landfill pile (25.6 degrees C) was slightly higher than that of semi-aerobic landfill file (24.8 degrees C), but the difference was not significant. During land-filling period, the O2 concentration in semi-aerobic landfill pile was significantly higher than that in anaerobic one, while the CH4 concentration was in reverse. After 5 years land-filling, the contents of easily degradable organic matters in aged refuse, such as kitchen refuses and papers, decreased dramatically, while the contents of plastics, glasses, bricks, and woods increased. In addition, the contents of organic matters and nutrients in aged refuse were higher than those in typical southern China soils, and the concentrations of heavy metals except chromium in anaerobic landfill aged refuse were not beyond the grade three of Environmental Quality Standards for Soils (GB 15618-1995).

[Activated brain areas during simple and complex mental calculation--a functional MRI study].

Functional magnetic resonance imaging (fMRI) was used to study the activated brain areas of human during simple and complex digital calculation, and to investigate the role of cortical and subcortical structures involved in the mental calculation. Sixteen right-handed healthy volunteers performed mental calculation of simple and complex addition/subtraction respectively, while the fMRI data were recorded by a Seimens 1.5 T MR machine. Block-design was used in the tasks. Two calculation tasks and one base-line tasks were performed for the block-design. Simple calculation task was single-digit addition and subtraction, while the complex was multi-digit addition and subtraction. The base-line task was to tell whether the two numbers were the same in every trial. Statistical parametric mapping (SPM99) was employed to process data and localize functional areas. We compared the average activation intensity of each activated brain regions in the same calculation task and the activation intensity of the same regions in both tasks respectively. Both the cortex and the subcortical structures including basal ganglia and thalamus were activated during simple and complex mental calculations. Similar brain regions in subjects including frontal lobe, parietal lobe, occipital lobe, cingulate gyrus, thalamus and cerebellum were engaged in simple and complex addition/subtraction. In the same task, activation intensity of all activated brain areas differed insignificantly. Compared with the complex task, the right parietal lobe was not activated in the simple one. The subcortical structures such as the caudate nucleus and the left marginal division of the striatum (MrD) were activated in both two calculation tasks. The cortical regions involved in both simple and complex addition/subtraction were similar. In conclusion, both the cortex and the subcortical structures were activated during the mental calculation. The cortex including the frontal cortex, parietal cortex, and cingulate gyrus were activated during mental calculation, while the subcortical structures such as the caudate nucleus, the globus pallidum and the left marginal division of the striatum also played a critical role in the neural networks of the calculation at the same time. Right parietal lobe (supramarginal gyrus) was engaged only in the complex task, which suggested that this region might be involved in the visuospatial memory and processing.

[Ionic exchange modification mechanism between organic modifier and Lou soil].

The ionic exchange modification mechanism between cationic organic modifier, cetyltrimethylammonium bromide (CTMAB), and two layers of Lou soil, tillage layer (TLLS) and clay layer (CLLS), were studied. The results show that a simple and effective index, sum of amounts of CTMAB and Ca2+/2 (Scc), can be used to judge the essence of modification mechanism between CTMAB and Lou soil. St(CC) demonstrates that the modification of CTMAB to two layers of Lou soil is the coexist of both ionic exchange and hydrophobic bond mechanism. The hydrophobic bond modification appears in the range of modification ratio 20%-28% CEC and linearly increases with an increase of both modification ratio and molar fraction of CTMAB, but its effects on the properties of soil become emergence just until 50% CEC modification ratio, and the hydrophobic bond mode exceeds the ionic exchange mode at about 100% CEC modification ratio and becomes main modification mechanism. The Vanselow selectivity coefficients show that the adsorption preference of Lou soil to CTMAB is stronger than that to calcium ion. The results of thermodynamics indicate that with an increase of modification ratio, the modification reaction transform from exothermic and entropy decrease to endothermic and entropy increase in the range of modification ratio 25% -100% CEC, while both pseudo enthalpy change and pseudo entropy change display a decrease trend in the range of modification ratio 100%-200% CEC, and in total, the modification reaction is a spontaneous reaction which controlled by entropy change in range of modification ratio 25% -100% CEC but controlled by enthalpy change in range of modification ratio 100%-200% CEC. The rationality of modification mechanism could be demonstrated by the results of thermodynamics.

Simultaneous adsorption of phenol and cadmium on amphoteric modified soil.

Surface modification is an effective way to enhance adsorption of pollutants by soil. In this study, we investigated the individual adsorption of cadmium ion (Cd(2+)) and phenol and also in combination by the clay layer of a loessial soil treated with the amphoteric modifier, duodalkylbetaine (BS-12). Three levels of BS-12 modification were compared in this experiment: (1) unmodified soil (CK), (2) modification with an amount of BS-12 equivalent to 50% of the soil's CEC (50BS) and (3) modification with an amount of BS-12 equivalent to 100% of the soil's CEC (100BS). Cd(2+) adsorption was 0.92-1.70 times higher in the amphoteric modified soil compared to unmodified soil. Adsorption isotherms for Cd(2+) displayed a L1-type shape. Phenol adsorption was 1.25-4.35 times higher in the amphoteric modified soil compared to the unmodified control. The adsorption isotherms of phenol on amphoteric modified soils were generally linear, but changed to L1-type isotherms for modified soil in the Cd(2+)+phenol treatment at 40 degrees C. The results clearly showed that amphoteric modified soil had the ability to simultaneously adsorb Cd(2+) and phenol. Cd(2+) adsorption by the amphoteric modified soil was related to the initial concentration of Cd(2+) in the supernatant. Cd(2+) adsorption in the 100BS treatment exceeded adsorption in the 50BS treatment when Cd(2+) initial concentrations were higher than approximate 200 microg mL(-1). Phenol adsorption by modified soils decreased in the order: 100BS>50BS>CK and was primarily determined by the surface hydrophobicity of the soil. For the unmodified soil, total adsorption in the Cd(2+)+phenol treatment was slightly lower compared to treatments that contained only Cd(2+) or phenol. This indicated an antagonistic effect between the adsorption of Cd(2+) and phenol, which was reduced after amphoteric modification. A comparison of temperature effects on Cd(2+) and phenol adsorption indicated that Cd(2+) was both physically and chemically adsorbed by the amphoteric modified soil, but phenol was primarily adsorbed physically.