Electron paramagnetic resonance imaging (EPRI) is a relatively recent imaging technique, which provides potentially multidimensional imaging of the spatial distribution of paramagnetic species. Thanks to the use of st...Electron paramagnetic resonance imaging (EPRI) is a relatively recent imaging technique, which provides potentially multidimensional imaging of the spatial distribution of paramagnetic species. Thanks to the use of stable spin probes, low frequency EPR imaging has recently allowed the use of large tissue samples or whole animals in vivo in the field of biology and medicine. It is normally necessary to introduce prior intravenous or intramuscular infusion of stable or slowly metabolizable non-toxic water-soluble paramagnetic materials, or stable implantable particulate materials as spin probes into the system. The classification and research progress of spin probes at present were described briefly. Three important potential approaches in water-soluble paramagnetic materials design including deuterated, site-specific and macromolecular conjugated nitroxides were also investigated.展开更多
NITRIC oxide (NO) is the important cell messenger molecule that regulates the central ner-vous, cardiovascular, endocrine and immunity systems. The study of NO not only canexplain many physiological phenomena, but als...NITRIC oxide (NO) is the important cell messenger molecule that regulates the central ner-vous, cardiovascular, endocrine and immunity systems. The study of NO not only canexplain many physiological phenomena, but also can provide new ways to prevent and treat alot of diseases. However, at present, most of the methods for assaying NO produced by or-ganism have some defects, for example, low sensitivity, no specificity, no convenience.展开更多
A nuclear spin gyroscope based on an alkali-metal–noble-gas co-magnetometer operated in spin-exchange relaxationfree(SERF) regime is a promising atomic rotation sensor for its ultra-high fundamental sensitivity. Howe...A nuclear spin gyroscope based on an alkali-metal–noble-gas co-magnetometer operated in spin-exchange relaxationfree(SERF) regime is a promising atomic rotation sensor for its ultra-high fundamental sensitivity. However, the fluctuation of probe light intensity is one of the main technical error sources that limits the bias stability of the gyroscope. Here we propose a novel method to suppress the bias error induced by probe light intensity fluctuations. This method is based on the inherent magnetic field response characteristics of the gyroscope. By the application of a bias magnetic field, the gyroscope can be tuned to a working point where the output signal is insensitive to probe light intensity variation, referred to herein as ‘zero point’, thus the bias error induced by intensity fluctuations can be completely suppressed. The superiority of the method was verified on a K–Rb–21 Ne co-magnetometer, and a bias stability of approximately 0.01°/h was obtained. In addition, the method proposed here can remove the requirement of the closed-loop control of probe light intensity, thereby facilitating miniaturization of the gyroscope volume and improvement of reliability.展开更多
Electron spin resonance (ESR) technique has been widely used as a modern biophysicalmethod in every field of life science. Spin probe method is a special ESR technique. Inorder to extend the biological application of ...Electron spin resonance (ESR) technique has been widely used as a modern biophysicalmethod in every field of life science. Spin probe method is a special ESR technique. Inorder to extend the biological application of the spin probe method.a nitroxide radicalanalogous to imidazole F was synthesized:展开更多
Oxygen spin probe method is a modern biophysics technique, which is applied to theobservation of metabolic process of oxygen in cells. Here, another application of thismethod is developed in our current work, in which...Oxygen spin probe method is a modern biophysics technique, which is applied to theobservation of metabolic process of oxygen in cells. Here, another application of thismethod is developed in our current work, in which the trace sample reaction’s kineticswas studied.Nitroxide free radical 3-carbamoyl-2, 2, 5, 5。展开更多
To construct pulsed high magnet, with rapid adjustments to large changes in the field strength, it is a mandatory acces-sory to development a special NMR probes to provide a precise real-time map of the magnetic field...To construct pulsed high magnet, with rapid adjustments to large changes in the field strength, it is a mandatory acces-sory to development a special NMR probes to provide a precise real-time map of the magnetic field. In order to do so, it is necessary to understand the variations of the spin transition and susceptibility of NMR samples in a time dependent longitudinal field. This work analyzes the effect on the spin transition by a time dependent longitudinal field. For a 1/2 spin system, we have derived a simple formula for the prediction of the probabilities of occupation of the 1/2 and ?1/2 states in a non-static field. We also calculate the magnetic susceptibility of the water and give an analysis of the effect on the magnetic susceptibility in a time dependent longitudinal field and RF frequency.展开更多
The polymer-polymer interaction parameters of STVPh/PPC blends were calculated by Hildebrand solubility parameter. Accordingly the miscibility of the blends was predicted. The segment motion and miscibility of blends ...The polymer-polymer interaction parameters of STVPh/PPC blends were calculated by Hildebrand solubility parameter. Accordingly the miscibility of the blends was predicted. The segment motion and miscibility of blends were also investigated by electron spin resonance(ESR) spin probe method. ESR spectra were measured as a function of temperature and the hydroxyl content in STVPh. For all blends, two spectral components with different rates of motion, a "fast" and a "slow" component were observed. This result showed that the nitrooxide radical existed in two different matrixes, a more flexible PPC-rich and a more rigid STVPh-rich micro domain. In addition, T 5mT and rotational correlation time τ c and activation energy E a were obtained from ESR spectra, which indicated the hydrogen bonding between the carbonyl and ether oxygen in PPC and the hydroxyl in STVPh was enhanced with increasing the hydroxyl content in STVPh.展开更多
A spin-labeling fluorophore(NA-TEMPO ·), formed by labeling α-naphthalene with a paramagnetic nitroxide(4-hydroxyl-2,2,6,6-tetramethylpiperidinyl-1-oxy), was explored for biologically relevant carbon-centered ra...A spin-labeling fluorophore(NA-TEMPO ·), formed by labeling α-naphthalene with a paramagnetic nitroxide(4-hydroxyl-2,2,6,6-tetramethylpiperidinyl-1-oxy), was explored for biologically relevant carbon-centered radicals. The horseradish peroxidase (HPR)/H 2O 2 reaction was used to generate radicals in derivatives of tyrosine and phenylalanine, and the Fenton reaction was used to generate radicals in deoxyguanosine, guanosine, bovine serum albumin(BSA) and DNA. TEMPO ·-NA, a weak fluorescent compound, showed a dramatic increase in fluorescence intensity after scavenging carbon-centered radicals. The spin-labeling fluorophore with dual function groups, the radical recognizing group and fluorescent group, would be significantly useful in monitoring the formation and translocation of carbon-centered radicals in complex biological systems.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.50773060)Hubei Provincial International Project for Science and Technology Cooperation (Grant No.2007CA015)+1 种基金Hubei Provincial Key Technologies Research and Development Program (Grant No.2007AA301B24)2007 Endeavour Research Award of the Australian Government (Grant ERF-PDR-194-2007)
文摘Electron paramagnetic resonance imaging (EPRI) is a relatively recent imaging technique, which provides potentially multidimensional imaging of the spatial distribution of paramagnetic species. Thanks to the use of stable spin probes, low frequency EPR imaging has recently allowed the use of large tissue samples or whole animals in vivo in the field of biology and medicine. It is normally necessary to introduce prior intravenous or intramuscular infusion of stable or slowly metabolizable non-toxic water-soluble paramagnetic materials, or stable implantable particulate materials as spin probes into the system. The classification and research progress of spin probes at present were described briefly. Three important potential approaches in water-soluble paramagnetic materials design including deuterated, site-specific and macromolecular conjugated nitroxides were also investigated.
文摘NITRIC oxide (NO) is the important cell messenger molecule that regulates the central ner-vous, cardiovascular, endocrine and immunity systems. The study of NO not only canexplain many physiological phenomena, but also can provide new ways to prevent and treat alot of diseases. However, at present, most of the methods for assaying NO produced by or-ganism have some defects, for example, low sensitivity, no specificity, no convenience.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFB0501600 and 2017YFB0503100)the National Natural Science Foundation of China(Grant Nos.61773043,61673041,and 61721091)
文摘A nuclear spin gyroscope based on an alkali-metal–noble-gas co-magnetometer operated in spin-exchange relaxationfree(SERF) regime is a promising atomic rotation sensor for its ultra-high fundamental sensitivity. However, the fluctuation of probe light intensity is one of the main technical error sources that limits the bias stability of the gyroscope. Here we propose a novel method to suppress the bias error induced by probe light intensity fluctuations. This method is based on the inherent magnetic field response characteristics of the gyroscope. By the application of a bias magnetic field, the gyroscope can be tuned to a working point where the output signal is insensitive to probe light intensity variation, referred to herein as ‘zero point’, thus the bias error induced by intensity fluctuations can be completely suppressed. The superiority of the method was verified on a K–Rb–21 Ne co-magnetometer, and a bias stability of approximately 0.01°/h was obtained. In addition, the method proposed here can remove the requirement of the closed-loop control of probe light intensity, thereby facilitating miniaturization of the gyroscope volume and improvement of reliability.
基金Project supported by the National Natural Science Foundation of China.
文摘Electron spin resonance (ESR) technique has been widely used as a modern biophysicalmethod in every field of life science. Spin probe method is a special ESR technique. Inorder to extend the biological application of the spin probe method.a nitroxide radicalanalogous to imidazole F was synthesized:
基金Project supported by the National Natural Science Foundation of China.
文摘Oxygen spin probe method is a modern biophysics technique, which is applied to theobservation of metabolic process of oxygen in cells. Here, another application of thismethod is developed in our current work, in which the trace sample reaction’s kineticswas studied.Nitroxide free radical 3-carbamoyl-2, 2, 5, 5。
文摘To construct pulsed high magnet, with rapid adjustments to large changes in the field strength, it is a mandatory acces-sory to development a special NMR probes to provide a precise real-time map of the magnetic field. In order to do so, it is necessary to understand the variations of the spin transition and susceptibility of NMR samples in a time dependent longitudinal field. This work analyzes the effect on the spin transition by a time dependent longitudinal field. For a 1/2 spin system, we have derived a simple formula for the prediction of the probabilities of occupation of the 1/2 and ?1/2 states in a non-static field. We also calculate the magnetic susceptibility of the water and give an analysis of the effect on the magnetic susceptibility in a time dependent longitudinal field and RF frequency.
文摘The polymer-polymer interaction parameters of STVPh/PPC blends were calculated by Hildebrand solubility parameter. Accordingly the miscibility of the blends was predicted. The segment motion and miscibility of blends were also investigated by electron spin resonance(ESR) spin probe method. ESR spectra were measured as a function of temperature and the hydroxyl content in STVPh. For all blends, two spectral components with different rates of motion, a "fast" and a "slow" component were observed. This result showed that the nitrooxide radical existed in two different matrixes, a more flexible PPC-rich and a more rigid STVPh-rich micro domain. In addition, T 5mT and rotational correlation time τ c and activation energy E a were obtained from ESR spectra, which indicated the hydrogen bonding between the carbonyl and ether oxygen in PPC and the hydroxyl in STVPh was enhanced with increasing the hydroxyl content in STVPh.
文摘A spin-labeling fluorophore(NA-TEMPO ·), formed by labeling α-naphthalene with a paramagnetic nitroxide(4-hydroxyl-2,2,6,6-tetramethylpiperidinyl-1-oxy), was explored for biologically relevant carbon-centered radicals. The horseradish peroxidase (HPR)/H 2O 2 reaction was used to generate radicals in derivatives of tyrosine and phenylalanine, and the Fenton reaction was used to generate radicals in deoxyguanosine, guanosine, bovine serum albumin(BSA) and DNA. TEMPO ·-NA, a weak fluorescent compound, showed a dramatic increase in fluorescence intensity after scavenging carbon-centered radicals. The spin-labeling fluorophore with dual function groups, the radical recognizing group and fluorescent group, would be significantly useful in monitoring the formation and translocation of carbon-centered radicals in complex biological systems.
