Harvesting clean energy from water evaporation has been extensively investigated due to its sustainability.To achieve high efficiency,energy conversion materials should contain multiple features which are difficult to...Harvesting clean energy from water evaporation has been extensively investigated due to its sustainability.To achieve high efficiency,energy conversion materials should contain multiple features which are difficult to be simultaneously obtained from single-component materials.Here we use composite laminar membranes assembled by nanosheets of graphene oxide and mica,and find a sustained power density induced by water evaporation that is two orders of magnitude larger than that from membranes made by either of the components.The power output is attributed to selective proton transport driven by water evaporation through the interlayer nanochannels in the membranes.This process relies on the synergistic effects from negatively charged and hydrophilic mica surfaces that are important for proton selectivity and water transport,and the tunable electrical conductivity of graphene oxide that provides optimized internal resistance.The demonstrated composite membranes offer a strategy of enhancing power generation by combining the advantages from each of their components.展开更多
Potassium （K） and nitrogen （N） are essential nutrients for plants. Adsorption and desorption in soils affect K＋ and NH4＋ avail- abilities to plants and can be affected by the interaction between the electrical d...Potassium （K） and nitrogen （N） are essential nutrients for plants. Adsorption and desorption in soils affect K＋ and NH4＋ avail- abilities to plants and can be affected by the interaction between the electrical double layers on oppositely charged particles because the interaction can decrease the surface charge density of the particles by neutralization of positive and negative charges. We studied the effect of iron （Fe）/aluminum （Al） hydroxides on desorption of K＋ and NH4＋ from soils and kaolinite and proposed desorption mechanisms based on the overlapping of diffuse layers between negatively charged soils and mineral particles and the positively charged Fe/Al hydroxide particles. Our results indicated that the overlapping of diffuse layers of electricM double layers between positively charged Fe/Al hydroxides, as amorphous Al（OH）3 or Fe（OH）3, and negatively charged surfaces from an Ultisol, an Alfisol, and a kaolinite standard caused the effective negative surface charge density on the soils and kaolinite to become less negative. Thus the adsorption affinity of these negatively charged surfaces for K＋ and NH4＋ declined as a result of the incorporation of the Fe/Al hydroxi- des. Consequently, the release of exchangeable K＋ and NH4＋ from the surfaces of the soils and kaolinite increased with the amount of the Fe/A1 hydroxides added. The greater the positive charge on the surfaces of Fe/Al hydroxides, the stronger was the interactive effect between the hydroxides and soils or kaolinite, and thus the more release of K＋ and NH4＋. A decrease in pH led to increased positive surface charge on the Fe/Al hydroxides and enhanced interactive effects between the hydroxides and soils/kaolinite. As a result, more K＋ and NH4＋ were desorbed from the soils and kaolinite. This study suggests that the interaction between oppositely charged particles of variable charge soils can enhance the mobility of K＋ and NH4＋ in the soils and thus increase their leaching loss.展开更多
Aim： To determine the short and long-term morphological effects on sperm as induced by intra-vas alteration of pH and electrical charge. Methods： Desired biophysical influences were obtained by injection of reversib...Aim： To determine the short and long-term morphological effects on sperm as induced by intra-vas alteration of pH and electrical charge. Methods： Desired biophysical influences were obtained by injection of reversible inhibition of sperm under guidance （RISUG） into the lumen of the vas deferens of human subjects and the monkey. RISUG is a polyelectrolyte hydrogel complex of styrene maleic anhydride （SMA） and dimethyl sulfoxide （DMSO） which generates an electrostatic charge and also lowers in a near space of pH domain. The morphology of sperm was examined by light microscopy, scanning and transmission electron microscopy. Human study enabled semen collection by masturbation as early as 3 h after injection and studies extended up to 6 months, in the monkey, on vas excision after RISUG implantation, sperm characteristics were examined in serial sections. Results： Semenology in clinical studies and histological data of the monkey showed a time-sequenced sperm plasma membrane, tail mitochondria and nuclear decondensation alterations in sperm structural components, which beared marked similarity to changes in the sperm head and tail during capacitation and entry into the ovum. Conclusion： The findings provide a means of causing such changes in the sperm that inhibit the fertilizing ability before the nucleus is affected. Therefore achieving non-obstructive vas-based contraception, without genotoxic or teratogenic effects caused by infertile sperm passing into the semen, is feasible.展开更多
An injury potential is the direct current potential difference between the site of spinal cord injury and the healthy nerves. Its initial amplitude is a significant indicator of the severity of spinal cord injury, and...An injury potential is the direct current potential difference between the site of spinal cord injury and the healthy nerves. Its initial amplitude is a significant indicator of the severity of spinal cord injury, and many cations, such as sodium and calcium, account for the major portion of injury potentials. This injury potential, as wel as injury current, can be modulated by direct current field stimulation;however, the appropriate parameters of the electrical field are hard to define. In this paper, injury potential is used as a parameter to adjust the intensity of electrical stimulation. Injury potential could be modulated to slightly above 0 mV （as the anode-centered group） by placing the anodes at the site of the injured spinal cord and the cathodes at the rostral and caudal sections, or around-70 mV, which is resting membrane potential （as the cathode-centered group） by reversing the polarity of electrodes in the anode-centered group. In addition, rats receiving no electrical stimulation were used as the control group. Results showed that the absolute value of the injury potentials acquired after 30 minutes of electrical stimulation was higher than the control group rats and much lower than the initial absolute value, whether the anodes or the cathodes were placed at the site of injury. This phenomenon il ustrates that by changing the polarity of the electrical field, electrical stimulation can effectively modulate the injury potentials in rats after spinal cord injury. This is also beneficial for the spontaneous repair of the cel membrane and the reduction of cation influx.展开更多
基金support from the National Key Research and Development Program of China(No.2019YFA0705400)the National Natural Science Foundation of China(Nos.21972121 and 22021001)the Fundamental Research Funds for the Central Universities(No.20720210017).
文摘Harvesting clean energy from water evaporation has been extensively investigated due to its sustainability.To achieve high efficiency,energy conversion materials should contain multiple features which are difficult to be simultaneously obtained from single-component materials.Here we use composite laminar membranes assembled by nanosheets of graphene oxide and mica,and find a sustained power density induced by water evaporation that is two orders of magnitude larger than that from membranes made by either of the components.The power output is attributed to selective proton transport driven by water evaporation through the interlayer nanochannels in the membranes.This process relies on the synergistic effects from negatively charged and hydrophilic mica surfaces that are important for proton selectivity and water transport,and the tunable electrical conductivity of graphene oxide that provides optimized internal resistance.The demonstrated composite membranes offer a strategy of enhancing power generation by combining the advantages from each of their components.
基金Supported by the Knowledge Innovation Program Foundation of the Chinese Academy of Sciences (No. KZCX2-EW-405)the National Natural Science Foundation of China (Nos. 40971135 and 40901110)
文摘Potassium （K） and nitrogen （N） are essential nutrients for plants. Adsorption and desorption in soils affect K＋ and NH4＋ avail- abilities to plants and can be affected by the interaction between the electrical double layers on oppositely charged particles because the interaction can decrease the surface charge density of the particles by neutralization of positive and negative charges. We studied the effect of iron （Fe）/aluminum （Al） hydroxides on desorption of K＋ and NH4＋ from soils and kaolinite and proposed desorption mechanisms based on the overlapping of diffuse layers between negatively charged soils and mineral particles and the positively charged Fe/Al hydroxide particles. Our results indicated that the overlapping of diffuse layers of electricM double layers between positively charged Fe/Al hydroxides, as amorphous Al（OH）3 or Fe（OH）3, and negatively charged surfaces from an Ultisol, an Alfisol, and a kaolinite standard caused the effective negative surface charge density on the soils and kaolinite to become less negative. Thus the adsorption affinity of these negatively charged surfaces for K＋ and NH4＋ declined as a result of the incorporation of the Fe/Al hydroxi- des. Consequently, the release of exchangeable K＋ and NH4＋ from the surfaces of the soils and kaolinite increased with the amount of the Fe/A1 hydroxides added. The greater the positive charge on the surfaces of Fe/Al hydroxides, the stronger was the interactive effect between the hydroxides and soils or kaolinite, and thus the more release of K＋ and NH4＋. A decrease in pH led to increased positive surface charge on the Fe/Al hydroxides and enhanced interactive effects between the hydroxides and soils/kaolinite. As a result, more K＋ and NH4＋ were desorbed from the soils and kaolinite. This study suggests that the interaction between oppositely charged particles of variable charge soils can enhance the mobility of K＋ and NH4＋ in the soils and thus increase their leaching loss.
文摘Aim： To determine the short and long-term morphological effects on sperm as induced by intra-vas alteration of pH and electrical charge. Methods： Desired biophysical influences were obtained by injection of reversible inhibition of sperm under guidance （RISUG） into the lumen of the vas deferens of human subjects and the monkey. RISUG is a polyelectrolyte hydrogel complex of styrene maleic anhydride （SMA） and dimethyl sulfoxide （DMSO） which generates an electrostatic charge and also lowers in a near space of pH domain. The morphology of sperm was examined by light microscopy, scanning and transmission electron microscopy. Human study enabled semen collection by masturbation as early as 3 h after injection and studies extended up to 6 months, in the monkey, on vas excision after RISUG implantation, sperm characteristics were examined in serial sections. Results： Semenology in clinical studies and histological data of the monkey showed a time-sequenced sperm plasma membrane, tail mitochondria and nuclear decondensation alterations in sperm structural components, which beared marked similarity to changes in the sperm head and tail during capacitation and entry into the ovum. Conclusion： The findings provide a means of causing such changes in the sperm that inhibit the fertilizing ability before the nucleus is affected. Therefore achieving non-obstructive vas-based contraception, without genotoxic or teratogenic effects caused by infertile sperm passing into the semen, is feasible.
基金supported by the National Natural Science Foundation of China,No.51177162
文摘An injury potential is the direct current potential difference between the site of spinal cord injury and the healthy nerves. Its initial amplitude is a significant indicator of the severity of spinal cord injury, and many cations, such as sodium and calcium, account for the major portion of injury potentials. This injury potential, as wel as injury current, can be modulated by direct current field stimulation;however, the appropriate parameters of the electrical field are hard to define. In this paper, injury potential is used as a parameter to adjust the intensity of electrical stimulation. Injury potential could be modulated to slightly above 0 mV （as the anode-centered group） by placing the anodes at the site of the injured spinal cord and the cathodes at the rostral and caudal sections, or around-70 mV, which is resting membrane potential （as the cathode-centered group） by reversing the polarity of electrodes in the anode-centered group. In addition, rats receiving no electrical stimulation were used as the control group. Results showed that the absolute value of the injury potentials acquired after 30 minutes of electrical stimulation was higher than the control group rats and much lower than the initial absolute value, whether the anodes or the cathodes were placed at the site of injury. This phenomenon il ustrates that by changing the polarity of the electrical field, electrical stimulation can effectively modulate the injury potentials in rats after spinal cord injury. This is also beneficial for the spontaneous repair of the cel membrane and the reduction of cation influx.
