To understand the tolerance to salinity and osmoregulation of the introduced Trachemys scripta elegans, the salinity stress of four groups （salinity 5‰, 15‰, 25‰ and control group） were conducted. Inorganic ions,...To understand the tolerance to salinity and osmoregulation of the introduced Trachemys scripta elegans, the salinity stress of four groups （salinity 5‰, 15‰, 25‰ and control group） were conducted. Inorganic ions, osmotic pressure, glucose and aldosterone of blood and urine in T. s. elegans （BW： 125.60 ±19.84 g） were analyzed at 30 d, 60 d and 90 d stress. The results showed that： 1） inorganic ions concentration of blood and urine increased with ambient salinity, which indicated that high influx of ions was combined with higher outflow when exposed to saline water in T. s. elegans. However, blood aldosterone decreased with increasing salinity, which indicated that an increased sodium intake resulting in a diminished aldosterone production. However, with elapsed time, inorganic ions in urine decreased, which indicated that inorganic ions in blood would be accumulated, and Na^＋ and Cl^- in the plasma inevitably build up to harmful levels, at last death was happening when T. s. elegans was exposed to salinity 25 during 90 d salinity stress; 2） blood osmotic pressure increased as ambient salinity increased, it would reach 400 mOsm/kg in the group of salinity 25, which was about 1.5 fold of the control group. Higher blood osmotic pressure was due to both higher blood ions and urea concentrations. There may be another mechanism to avoid an excess of NaCl together with an important loss of water using one of the end-products of nitrogen metabolism; 3） blood glucose in each group except the group of salinity 5 decreased with time elapsed and with salinity increased. Therefore, we can conclude that T. s. elegans is an osmoregulator that limits the entry of Na^＋ and Cl^-, but can also tolerate certain degrees of increases in plasma Na^＋ and Cl^-. When ambient salinity was lower than 15‰, T. s. elegans can increase blood osmotic pressure by balancing the entry of NaCl with the secretion of aldosterone decreased, and by accumulating blood urea for osmoregulation effectors, and survive for at least three months. These results could provide theoretical basis for salinity tolerance and the invasion on physiological mechanism for T. s. elegans.展开更多
The high-pressure structural,vibrational and electrical properties for realgar were investigated by in-situ Raman scattering and electrical conductivity experiments combined with first-principle calculations up to~30....The high-pressure structural,vibrational and electrical properties for realgar were investigated by in-situ Raman scattering and electrical conductivity experiments combined with first-principle calculations up to~30.8 GPa.It was verified that realgar underwent an isostructural phase transition at~6.3 GPa and a metallization at a higher pressure of~23.5 GPa.The isostructural phase transition was well evidenced by the obvious variations of Raman peaks,electrical conductivity,crystal parameters and the As–S bond length.The phase transition of metallization was in closely associated with the closure of bandgap rather than caused by the structural phase transition.And furthermore,the metallic realgar exhibited a relatively low compressibility with the unit cell volume V_(0)=718.1.4Å^(3)and bulk modulus B_(0)=36.1 GPa.展开更多
The vibrational and electrical transport properties of natural siderite are systematically investigated by means of in-situ Raman spectroscopy and alternating current impedance spectroscopy under conditions of 0.6-55....The vibrational and electrical transport properties of natural siderite are systematically investigated by means of in-situ Raman spectroscopy and alternating current impedance spectroscopy under conditions of 0.6-55.6 GPa,298-873 K and different hydrostatic environments using a diamond anvil cell(DAC).Upon non-hydrostatic compression,all of these observable characteristic variations of siderite including the appearance of three absolutely new Raman peaks(L’,v4'and v1'),the disappearance of Raman peaks(T,L and v4)and the discontinuity in the pressure-dependent electrical conductivity can provide robust evidence of electronic spin transitions of Fe^(2+)from high-spin to mixed-spin to low-spin states at the respective pressures of 42.5 GPa and 48.5 GPa.As far as hydrostatic condition,the electronic spin states from high-spin to mixed-spin to low-spin states occurred at the higher pressures of 45.7 GPa and 50.4 GPa,respectively,which implied the highly sensitive hydrostaticity of electronic spin transition pressures.Upon decompression,the reverse electronic spin transitions from low-spin to mixed-spin to high-spin states were detected at the respective pressures of 47.2 GPa and 28.7 GPa under non-hydrostatic condition,and as well as at the pressures of 49.4 GPa and 25.1 GPa under hydrostatic condition,respectively.The huge pressure hysteresis of 13.8 GPa and 20.6 GPa for the electronic spin state transition was revealed under non-hydrostatic and hydrostatic environments,respectively.In order to explore the effect of temperature on the electronic spin transition,a series of electrical conductivity experiments on siderite were performed over the temperature range of 323-873 K under conditions of three typical pressures of 47.7,49.8 and 51.6 GPa.Furthermore,the functional relationships between the temperature and pressure describing the high-spin to mixed-spin to low-spin transitions for siderite were successfully established:P1(GPa)=39.318+0.015 T(K)and P2(GPa)=41.277+0.018 T(K),respectively.In conclusion,our acquired phase diagram of the electronic spin transition on siderite is beneficial to deep insight into the electronic spin behavior for those of iron-bearing carbonate minerals under high-temperature and high-pressure conditions.展开更多
基金the project of National Natural Science Foundation of China (Nos. 31360642 and 31372228)Key Project of Chinese Ministry of Education (No.211145)Natural Science Foundation of Hainan Province of China (No. 303148)" for financial support
文摘To understand the tolerance to salinity and osmoregulation of the introduced Trachemys scripta elegans, the salinity stress of four groups （salinity 5‰, 15‰, 25‰ and control group） were conducted. Inorganic ions, osmotic pressure, glucose and aldosterone of blood and urine in T. s. elegans （BW： 125.60 ±19.84 g） were analyzed at 30 d, 60 d and 90 d stress. The results showed that： 1） inorganic ions concentration of blood and urine increased with ambient salinity, which indicated that high influx of ions was combined with higher outflow when exposed to saline water in T. s. elegans. However, blood aldosterone decreased with increasing salinity, which indicated that an increased sodium intake resulting in a diminished aldosterone production. However, with elapsed time, inorganic ions in urine decreased, which indicated that inorganic ions in blood would be accumulated, and Na^＋ and Cl^- in the plasma inevitably build up to harmful levels, at last death was happening when T. s. elegans was exposed to salinity 25 during 90 d salinity stress; 2） blood osmotic pressure increased as ambient salinity increased, it would reach 400 mOsm/kg in the group of salinity 25, which was about 1.5 fold of the control group. Higher blood osmotic pressure was due to both higher blood ions and urea concentrations. There may be another mechanism to avoid an excess of NaCl together with an important loss of water using one of the end-products of nitrogen metabolism; 3） blood glucose in each group except the group of salinity 5 decreased with time elapsed and with salinity increased. Therefore, we can conclude that T. s. elegans is an osmoregulator that limits the entry of Na^＋ and Cl^-, but can also tolerate certain degrees of increases in plasma Na^＋ and Cl^-. When ambient salinity was lower than 15‰, T. s. elegans can increase blood osmotic pressure by balancing the entry of NaCl with the secretion of aldosterone decreased, and by accumulating blood urea for osmoregulation effectors, and survive for at least three months. These results could provide theoretical basis for salinity tolerance and the invasion on physiological mechanism for T. s. elegans.
基金the strategic priority Research Program(B)of the Chinese Academy of Sciences(Grant No.18010401)Key Research Program of Frontier Sciences of CAS(Grant No.QYZDB-SSW-DQC009)+3 种基金Hundred Talents Program of CAS,NSF of China(Grant Nos.41774099 and 41772042)Youth Innovation Promotion Association of CAS(Grant No.2019390)Special Fund of the West Light Foundation of CASthe Supercomputer Center of Fujian Institute of Research on the Structure of Matter(FJIRSM)is acknowledged.
文摘The high-pressure structural,vibrational and electrical properties for realgar were investigated by in-situ Raman scattering and electrical conductivity experiments combined with first-principle calculations up to~30.8 GPa.It was verified that realgar underwent an isostructural phase transition at~6.3 GPa and a metallization at a higher pressure of~23.5 GPa.The isostructural phase transition was well evidenced by the obvious variations of Raman peaks,electrical conductivity,crystal parameters and the As–S bond length.The phase transition of metallization was in closely associated with the closure of bandgap rather than caused by the structural phase transition.And furthermore,the metallic realgar exhibited a relatively low compressibility with the unit cell volume V_(0)=718.1.4Å^(3)and bulk modulus B_(0)=36.1 GPa.
基金supported by the NSF of China(Grant Nos.42072055,42274137 and 42302047).
文摘The vibrational and electrical transport properties of natural siderite are systematically investigated by means of in-situ Raman spectroscopy and alternating current impedance spectroscopy under conditions of 0.6-55.6 GPa,298-873 K and different hydrostatic environments using a diamond anvil cell(DAC).Upon non-hydrostatic compression,all of these observable characteristic variations of siderite including the appearance of three absolutely new Raman peaks(L’,v4'and v1'),the disappearance of Raman peaks(T,L and v4)and the discontinuity in the pressure-dependent electrical conductivity can provide robust evidence of electronic spin transitions of Fe^(2+)from high-spin to mixed-spin to low-spin states at the respective pressures of 42.5 GPa and 48.5 GPa.As far as hydrostatic condition,the electronic spin states from high-spin to mixed-spin to low-spin states occurred at the higher pressures of 45.7 GPa and 50.4 GPa,respectively,which implied the highly sensitive hydrostaticity of electronic spin transition pressures.Upon decompression,the reverse electronic spin transitions from low-spin to mixed-spin to high-spin states were detected at the respective pressures of 47.2 GPa and 28.7 GPa under non-hydrostatic condition,and as well as at the pressures of 49.4 GPa and 25.1 GPa under hydrostatic condition,respectively.The huge pressure hysteresis of 13.8 GPa and 20.6 GPa for the electronic spin state transition was revealed under non-hydrostatic and hydrostatic environments,respectively.In order to explore the effect of temperature on the electronic spin transition,a series of electrical conductivity experiments on siderite were performed over the temperature range of 323-873 K under conditions of three typical pressures of 47.7,49.8 and 51.6 GPa.Furthermore,the functional relationships between the temperature and pressure describing the high-spin to mixed-spin to low-spin transitions for siderite were successfully established:P1(GPa)=39.318+0.015 T(K)and P2(GPa)=41.277+0.018 T(K),respectively.In conclusion,our acquired phase diagram of the electronic spin transition on siderite is beneficial to deep insight into the electronic spin behavior for those of iron-bearing carbonate minerals under high-temperature and high-pressure conditions.
