BACKGROUND AND AIMS: For the last decade, there has been an increasing global interest in using biochar to mitigate climate change by storing carbon in soil. However, there is a lack of detailed ...knowledge on the impact of biochar on the crop productivity in different agricultural systems. The objective of this study was to quantify the effect of biochar soil amendment (BSA) on crop productivity and to analyze the dependence of responses on experimental conditions. METHODS: A weighted meta-analysis was conducted based on data from 103 studies published up to April, 2013. The effect of BSA on crop productivity was quantified by characterizing experimental conditions. RESULTS: In the published experiments, with biochar amendment rates generally <30 t ha⁻¹, BSA increased crop productivity by 11.0 % on average, while the responses varied with experimental conditions. Greater responses were found in pot experiments than in field, in acid than in neutral soils, in sandy textured than in loam and silt soils. Crop response in field experiments was greater for dry land crops (10.6 % on average) than for paddy rice (5.6 % on average). This result, associated with the higher response in acid and sandy textured soils, suggests both a liming and an aggregating/moistening effect of BSA. CONCLUSIONS: The analysis suggests a promising role for BSA in improving crop productivity especially for dry land crops, and in acid, poor-structured soils though there was wide variation with soil, crop and biochar properties. Long-term field studies are needed to elucidate the persistence of BSA’s effect and the mechanisms for improving crop production in a wide range of agricultural conditions. At current prices and C-trading schemes, however, BSA would not be cost-effective unless persistent soil improvement and crop response can be demonstrated.
Full text
Available for:
BFBNIB, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NMLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Competitive utilization of straw is a challenge faced by developing countries such as China with the increase of crop production. Biochar, briquette fuel and combined heat and power generation are ...the three main new measures for straw utilization in recent years; however, there is still a knowledge gap for environmental and economic effects of these utilizations in China. To address this issue, combined life-cycle analysis and cost-benefit analysis was employed to assess the environmental impacts and economic benefits of biochar, briquette fuel and combined heat and power generation applications based on three cases in China. The results suggested that biochar was the most promising technology for straw utilization in China for its highest greenhouse gas mitigation potential i.e. −0.94 t CO2 equivalent (CO2e) per ton straw utilized and high profit with a net present value per ton straw of 20.98 U.S. dollars with the baseline of crop straw return including carbon revenue. Briquette fuel also deserves to achieve a best net present value ratio of 5.06 and GHG abatement potential being −0.9 t CO2e t−1 straw. However, the waste of straw ash could bring some pollution risk without suitable treatment. The economic potential of the combined heat and power generation project that produces bioelectricity, is not considerable with a very low net present value ratio of 0.007 and a mitigation potential of −0.03 tCO2e t−1 straw due to low energy utilization efficiency of direct combustion. Biochar could be one of the most potential economic and environmental sustainable straw utilization technologies in China though the wide production and application is still a big challenge in future.
•The environmental impacts and economic efficiency of different crop residue competitive utilization were assessed.•Biochar was one of the most promising straw utilization measures for its highest carbon abatement and economic profit.•The sensitivity of carbon abatement potential and economic performance to key parameters was further evaluated.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Biochar soil amendment had been increasingly advocated for improving crop productivity and reducing carbon footprint in agriculture worldwide. However, the long-term benefits of biochar application ...with farming systems had not been thoroughly understood. This study quantified and assessed emergy, energy, and economic benefits of rice and wheat production throughout 6 rotation years following a single biochar amendment in a rice paddy from Southeastern China. Using the data from farm inventory, the quantified emergy indices included grain outputs, unit emergy value, and relative percentage of free renewable resources, environmental loading ratio, emergy yield ratio, and emergy sustainability index (ESI). The results indicated contrasting differences in these emergy values between biochar-amended and unamended production systems over the 6 years. The overall emergy efficiency of rice and wheat productions in biochar-amended system were higher by 11–28 and 15–47%, respectively, than that of unamended one of which the production being highly resource intensive. Moreover, ESI on average was 0.46 for rice and 0.63 for wheat in amended system, compared to 0.35 for rice and 0.39 for wheat in unamended one. Furthermore, over the 6 years following a single application, the ESI values showed considerable variation in the unamended system but consistently increasing in the amended system. Again, the biochar-amended system exerted significantly higher energy and economic return than the unamended one. Nonetheless, there was a tradeoff between rice and wheat in grain yield and net economic gain. Overall, biochar amendment could be a viable measure to improve the resilience of grain production while to reduce resource intensity and environment impacts in paddy soil from China.
Background and aims For the last decade, there has been an increasing global interest in using biochar to mitigate climate change by storing carbon in soil. However, there is a lack of detailed ...knowledge on the impact of biochar on the crop productivity in different agricultural systems. The objective of this study was to quantify the effect of biochar soil amendment (BSA) on crop productivity and to analyze the dependence of responses on experimental conditions. Methods A weighted meta-analysis was conducted based on data from 103 studies published up to April, 2013. The effect of BSA on crop productivity was quantified by characterizing experimental conditions. Results In the published experiments, with biochar amendment rates generally < 30 t ha⁻¹, BSA increased crop productivity by 11.0 % on average, while the responses varied with experimental conditions. Greater responses were found in pot experiments than in field, in acid than in neutral soils, in sandy textured than in loam and silt soils. Crop response in field experiments was greater for dry land crops (10.6 % on average) than for paddy rice (5.6 % on average). This result, associated with the higher response in acid and sandy textured soils, suggests both a liming and an aggregating/moistening effect of BSA. Conclusions The analysis suggests a promising role for BSA in improving crop productivity especially for dry land crops, and in acid, poor-structured soils though there was wide variation with soil, crop and biochar properties. Long-term field studies are needed to elucidate the persistence of BSA's effect and the mechanisms for improving crop production in a wide range of agricultural conditions. At current prices and C-trading schemes, however, BSA would not be cost-effective unless persistent soil improvement and crop response can be demonstrated.
Full text
Available for:
BFBNIB, DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NMLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The pressure drop of gas-liquid two-phase flow in microchannel is of fundamental importance in heat and mass transfer processes. In this work,the pressure drop of gas-liquid two-phase flow in ...horizontal rectangular cross-section microchannels was measured by a pressure differential transducer system. Water,ethanol and n-propanol were used as liquid phase to study the effects of capillary number on pressure drop;air was used as the gas phase. Four microchannels with various dimensions of 100 μm × 200 μm,100 μm × 400 μm,100 μm × 800 μm and 100 μm × 2000 μm（depth × width） were used for determining the influence of configuration on the pressure drop. Experimental results showed that in micro-scale,the capillary number also affected the pressure drop remarkably,and in spite of only one-fold difference in aspect ratio,the variation of pressure drop reached up to near three times under the same experimental conditions. Taking the effects of aspect ratio and surface tension into account,a modi-fied correlation for Chisholm parameter C in the Chisholm model was proposed for predicting the frictional multi-plier,and the predicted values by the proposed correlation showed a satisfactory agreement with experimental data.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
External stimuli, such as ultrasound, magnetic field, and light, can be applied to activate in vivo tumor targeting. Herein, we fabricated polymer encapsulated gold nanorods to couple the ...photothermal properties of gold nanorods and the thermo- and pH-responsive properties of polymers in a single nanocomposite. The activation mechamism was thus transformed from heat to near-infrared (NIR) laser, which can be more easily controlled. Doxorubicin, a clinical anticancer drug, can be loaded into the nanocomposite through electrostatic interactions with high loading content up to 24%. The nanocomposite’s accumulation in tumor post systematic administration can be significantly enhanced by NIR laser irradiation, providing a prerequisite for their therapeutic application which almost completely inhibited tumor growth and lung metastasis. Since laser can be manipulated very precisely and flexibly, the nanocomposite provides an ideally versatile platform to simultaneously deliver heat and anticancer drugs in a laser-activation mechanism with facile control of the area, time, and dosage. The NIR laser-induced targeted cancer thermo-chemotherapy without using targeting ligands represents a novel targeted anticancer strategy with facile control and practical efficacy.
Full text
Available for:
IJS, KILJ, NUK, PNG, UL, UM
Mesoporous silica‐coated gold nanorods (Au@SiO2) are developed as a promising and versatile theranostic platform for cancer treatment. Intracellular localization of Au@SiO2 is visualized through ...two‐photon imaging. With doxorubicin hydrochloride loaded, Au@SiO2–DOX show two light‐mediated therapeutic modes: low power density laser‐triggered drug release for chemotherapy, and high power density laser‐induced hyperthermia, which suggest the potential for in‐vivo applications.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract Gold nanorods (Au NRs) have been recognized as promising materials for biomedical applications, like sensing, imaging, gene and drug delivery and therapy, but their toxicological issues are ...still controversial, especially for the Au NRs synthesized with seed-mediated method. In this study, we investigated the influence of aspect ratio and surface coating on their toxicity and cellular uptake. The cellular uptake is highly dependent on the aspect ratio and surface coating. However, the surface chemistry has the dominant roles since PDDAC-coated Au NRs exhibit a much greater ability to be internalized by the cells. The present data demonstrated shape-independent but coating-dependent cytotoxicity. Both the CTAB molecules left in the suspended solution and on the surface of Au NRs were identified as the actual cause of cytotoxicity. CTAB can enter cells with or without Au NRs, damage mitochondria, and then induce apoptosis. The effects of surface coating upon toxicity and cellular uptake were also examined using Au NRs with different coatings. When Au NRs were added into the medium, the proteins were quickly adsorbed onto the Au NRs that made the surface negatively charged. The surface charge may not directly affect the cellular uptake. We further demonstrated that the amount of serum proteins, especially for BSA, adsorbed on the Au NRs had a positive correlation with the capacity of Au NRs to enter cells. In addition, we have successfully revealed that the cationic PDDAC-coated Au NRs with an aspect ratio of 4 possess an ideal combination of both negligible toxicity and high cellular uptake efficiency, showing a great promise as photothermal therapeutic agents.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Covalent organic frameworks (COFs) are one booming class of porous materials that are assembled through covalent bonds. Owing to the excellent properties including three-dimensional frameworks, large ...specific surface, porous structure, multiple functional groups, good absorptivity, flexible design about various COFs, it has been introduced in sample preparation and some efficient COF coatings have been developed for solid-phase microextraction (SPME). COFs can be synthesized by different methods, and they also can be functionalized or modified for the regulation of their properties, so as to improve extraction performance. These COF materials presented good extraction effect to organic pollutants from diverse samples. This review paper focuses on the classification of COFs and their applications in SPME (direct immersion fiber SPME, headspace fiber SPME, and other SPME) as well as the extraction mechanism (π-π stacking, hydrogen bonding, hydrophobic, hydrophilic and electrostatic interactions, etc.) for various analytes in recent five years. Based on the flexible design and rich functionalization, COFs have large potential applications in sample preparation, and an outlook for current challenges and future trends about the development of COFs for SPME is also given.
•The main types of COFs are described.•The recent advances of COFs in direct immersion SPME are reviewed.•The recent advances of COFs in headspace SPME are reviewed.•The recent advances of COFs in other SPME are reviewed.•The prospects and challenges of COFs in the field of SPME are discussed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
