[Objective] This study aimed to investigate the effects of three kinds of diuretics on the water drinking amount and urination volume of sheep fed with cottonseed hulls. [Method] The method of self-control was adopted...[Objective] This study aimed to investigate the effects of three kinds of diuretics on the water drinking amount and urination volume of sheep fed with cottonseed hulls. [Method] The method of self-control was adopted. Five two-year-old male Kazak sheep about 40 kg which never had intake of the feeds containing gossypol were selected. The experiment was divided into five periods, namely the control period, a period with the supplement of 300 mg/d of hydrochlorothiazide, a period with the supplement of 200 mg/d of hydrochlorothiazide, a period with the supplement of 350 mg of GY-01 and a period with the supplement of 200 mg of GY-01. The sheep were fed with the concentrate and the cottonseed hulls in the control period, and corresponding diuretics were supplemented in the rest four periods. The water drinking amount, urination volume and the contents of the hormone and ion in the blood were determined in each period. [Result] After 350 mg GY-01 was supplemented, the water drinking amount of each sheep had an increase of 60.14% compared with that of the sheep in the control period and the urination volume was 2.67 times of that of the latter, and the differences were both significant （P0.01）. The antidiuretic hormone declined by 32.59% compared with that of the sheep in the control period, with the significant difference （P 0.05）. The adrenocorticotropic hormone content increased by 81.93% compared with that of the sheep in the control period and the difference was significant （P0.01）. An increase of 28.04% （P 0.05） and 39.39% （P 0.01） was found in the contents of serum potassium and phosphorus respectively compared with that of sheep in the control period. [Conclusion] The diet with supplement of GY-01 can increase the urination volume of livestock fed with the cottonseed hulls, and the most appropriate supplement amount is 200 mg GY-01.展开更多
Background. Our previous studies indicated that the increased arginine vasopressin(AVP) in ischemic brain regions of gerbils could exacerbate the ischemic brain edema. This experiments is further clarify the relation ...Background. Our previous studies indicated that the increased arginine vasopressin(AVP) in ischemic brain regions of gerbils could exacerbate the ischemic brain edema. This experiments is further clarify the relation between AVP and cerebral ischemia at the molecular level. Methods. The contents of AVP, AVP mRNA, AVP immunoreactive(ir) neurons in supraoptic nucleus(SON) and paraventricular nucleus(PVN) after cerebral ischemia and reperfusion were respectively determined by radioimmunoassay(RIA), immunocytochemistry(ⅡC), situ hybridization and computed image pattern analysis. Results. The contents of AVP in SON, PVN were increased, and the AVP ir positive neurons in SON and PVN were also significantly increased as compared with the controls after ischemia and reperfusion. And there were very light staining of AVP ir positive neurons in the other brain areas such as suprachiasmatic nucleus (SC) and periventricular hypothalamic nucleus (PE), but these have no significant changes as compared with the controls. During different periods of cerebral ischemia (30～120 min) and reperfusion (30 min), AVP mRNA expression in SON and PVN were more markedly increased than the controls. Conclusions. The transcription of AVP gene elevated, then promoting synthesis and release of AVP in SON, PVN. Under the specific condition of cerebral ischemia and reperfusion, the activity and contents of central AVP increased abnormally is one of the important factors which causes ischemia brain damage.展开更多
Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N ferti...Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N fertilizer treatments, applied in triplicate, were 0 （control）, 100, 200, 300, or 350 kg N ha^-1. After urea was applied to the surface water, a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field. Total N losses through ammonia volatilization generally increased with the N application rate, and the two higher N application rates （300 and 350 kg N ha^-1） showed a higher ratio of N lost through ammonia volatilization to applied N. Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N. Increasing the application rate generally decreased the ratio of N in the seed to N in the plant. For all N treatments, the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%. Surplus N with the highest N rate resulted in lodging of rice plants, a decreased rate of nitrogen fertilizer utilization, and reduced rice yields. Calculated from this experiment, the most economical N fertilizer application rate was 227 kg ha^-1 for the type of paddy soil in the Taihu Lake region. However, recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.展开更多
Spontaneous Ca2+ oscillations in vascular smooth muscle cells have been modeled using a single Ca2+ pool. This report describes spontaneous Ca2+ oscillations dependent on two separate Ca2+ sources for the nuclear vers...Spontaneous Ca2+ oscillations in vascular smooth muscle cells have been modeled using a single Ca2+ pool. This report describes spontaneous Ca2+ oscillations dependent on two separate Ca2+ sources for the nuclear versus cytoplas- mic compartments. Changes in free intracellular Ca2+ were monitored with ratiometric Ca2+- fluorophores using confo- cal microscopy. On average, spontaneous oscillations developed in 79% of rat aortic smooth muscle cells that were synchronous between the cytoplasm and nucleus. Reduction of extracellular Ca2+ (< 1 μM) decreased the frequency and amplitude of the cytoplasmic oscillations with 48% of the oscillations asynchronous between the nuclear and cytoplasmic compartments. Similar results were obtained with the Ca2+ channel blockers, nimodipine and diltiazem. Arg-vasopressin (AVP) induced a rapid release of intracellular Ca2+ stores that was greater in the nuclear compartment (4.20 ± 0.23 ratio units, n = 56) than cytoplasm (2.54 ± 0.28) in cells that had spontaneously developed prior oscillations. Conversely, cells in the same conditions lacking oscillations had a greater AVP-induced Ca2+ transient in the cytoplasm (4.99 ± 0.66, n = 17) than in the nucleus (2.67 ± 0.29). Pre-treatment with Ca2+ channel blockers depressed the AVP responses in both compartments with the cytoplasmic Ca2+ most diminished. Depletion of internal Ca2+ stores prior to AVP exposure blunted the nuclear response, mimicking the response of cells that lacked prior oscillations. Spontaneous oscillating cells had a greater sarcoplasmic reticulum network than cells that did not oscillate. We propose that sponta- neous nuclear oscillations rely on perinuclear sarcoplasmic reticulum stores, while the cytoplasmic oscillations rely on Ca2+ influx.展开更多
Mongolian gerbils were used as delayed neuronal damage (DNDi animal models. At the end of 15Abstract:Mongolian gerbils were used as delayed neuronal damage (DND)animal models. At the end of 15 minute cerebral ischemi...Mongolian gerbils were used as delayed neuronal damage (DNDi animal models. At the end of 15Abstract:Mongolian gerbils were used as delayed neuronal damage (DND)animal models. At the end of 15 minute cerebral ischemia and at various reperfusion time ranging from 1 to 96 hours, the content of water and arginine vasopressin (AVP) in the CA1 sector of hippocampus were measured by the specific gravity method and radioimmunoassay. Furthermore, we also examined the effect of intracerebroventricular (ICV) injection of AVP, AVP antiserum on calcium, Na+, K+-ATPase activrty in the CA1 sector after ischemia and 96 hour reperfusion. The results showed that AVP contents of CA1 sector of hippocampus during 6 to 96 hour recirculation, and the water content of CA1 sector during 24 to 96 hour were significantly and continuously increased. After ICV inJection of AVP, the water content and calcium in CA1 sector of hippocampus at cerebral ischemia and 96 hour recirculation further increased, and the Na+, K+- ATPase activity in CA1 sector was remarkably decreased as compared with that of control. While ICV injection of AVP antiserum, the water content and calcium in CA1 sector were significantly decreased as com pared with that of control. These suggested that AVP was involved in the pathophysiologic process of DND in hippocampus following cerebral ischemia and reperfusion. Its mechanism might be through the change of intracellular action mediated by specific AVP receptor to lead to Ca ions over-load of neuron and inhibit the Na+, K+- ATPase activity , thereby to exacerbate the DND in hippocampus.展开更多
Ascites is one of the major complications of liver cirrhosis and is associated with a poor prognosis. It is important to distinguish noncirrhotic from cirrhotic causes of ascites to guide therapy in patients with nonc...Ascites is one of the major complications of liver cirrhosis and is associated with a poor prognosis. It is important to distinguish noncirrhotic from cirrhotic causes of ascites to guide therapy in patients with noncirrhotic ascites. Mild to moderate ascites is treated by salt restriction and diuretic therapy. The diuretic of choice is spironolactone. A combination treatment with furosemide might be necessary in patients who do not respond to spironolactone alone. Tense ascites is treated by paracentesis, followed by albumin infusion and diuretic therapy. Treatment options for refractory ascites include repeated paracentesis and transjugular intrahepatic portosystemic shunt placement in patients with a preserved liver function. Potential complications of ascites are spontaneous bacterial peritonitis (SBP) and hepatorenal syndrome (HRS). SBP is diagnosed by an ascitic neutrophil count > 250 cells/mm3 and is treated with antibiotics. Patients who survive a first episode of SBP or with a low protein concentration in the ascitic fluid require an antibiotic prophylaxis. The prognosis of untreated HRS type 1 is grave. Treatment consists of a combination of terlipressin and albumin. Hemodialysis might serve in selected patients as a bridging therapy to liver transplantation. Liver transplantation should be considered in all patients with ascites and liver cirrhosis.展开更多
1,3-disubstituted ureas of adamantine series are potent for hypertension and inflammatory treatment. The most valuable parameters of these compounds are melting point and solubility. Higher melting point leads to lowe...1,3-disubstituted ureas of adamantine series are potent for hypertension and inflammatory treatment. The most valuable parameters of these compounds are melting point and solubility. Higher melting point leads to lower bioavailability and for most of the compounds investigated before it was very high. Usage of isocyanates containing 1,3-dimethyladamantane fragment will significantly decrease the melting point, improve solubility and therefore improve bioavailability of 1,3-disubstituted ureas and other biologically active compounds produced on its base. This article presents new 1,3-disubstituted ureas and biureas synthesized by the authors.展开更多
Objective： To evaluate plasma arginine vasopressin （AVP） level in patients with traumatic brain injury and investigate the role of AVP in the process of brain edema. Methods ： A total of 30 patients with traumatic...Objective： To evaluate plasma arginine vasopressin （AVP） level in patients with traumatic brain injury and investigate the role of AVP in the process of brain edema. Methods ： A total of 30 patients with traumatic brain injury were involved in our study. They were divided into two groups by Glasgow Coma Scale： severe tranmatic brain injury group （ STBI, GCS ≤ 8 ） and moderate traumatic brain injury group （ MTBI, GCS 〉 8 ）. Samples of venous blood were collected in the morning at rest from 15 healthy volunteers （control group）and within 24 h after traumatic brain injury from these patients for AVP determinations by radioimmunoassay. The severity and duration of the brain edema were estimated by head CT scan. Results： plasma AVP levels （ng/L） were （mean± SD） control, 3.06 ± 1.49; MTBI, 38. 12 ± 7. 25; andSTBI, 66. 61 ± 17. 10. The plasma level of AVP was significantly increased within 24 h after traumatic brain injury and followed by the reduction of GCS, suggesting the deterioration of cerebral injury （ P 〈 0.01 ）. And the AVP level was correlated with the severity （ STBI r = 0. 919, P 〈 0.01 ; MTBI r = 0. 724, P 〈 0.01 ） and the duration of brain edema （STBI r =0.790, P 〈0.01; MTBI r =0.712, P〈0.01）. Conclusions. The plasma AVP level is dosely associated with the severity of traumatic brain injury. AVP may play an important role in pathogenesis of brain edema after traumatic brain injury.展开更多
The effectiveness of polyolefin-coated urea （Meister-5 and Meister-10; CU） in a wheat （Triticum aestivum L.）-maize （Zea mays L.） rotation system was studied in lysimeter plots located in the North China Plain fo...The effectiveness of polyolefin-coated urea （Meister-5 and Meister-10; CU） in a wheat （Triticum aestivum L.）-maize （Zea mays L.） rotation system was studied in lysimeter plots located in the North China Plain for three consecutive maizewheat-maize cropping seasons. An isotopic method was used to compare the fate of CU to that of non-coated urea （NCU）, and N application rates of 0, 100, 150 and 225 kg N ha-1 were evaluated. The results showed that the nitrogen use efficiency （15NUE） of CU was 13.3%-21.4% greater than that of NCU for the first crop. Alternatively, when the difference method was applied （apparent NUE）, no significant variations were observed among treatments in all three seasons. Although inorganic N leached from the 1.3 m layer was less than 1% of the total applied N, unidentified losses of 15N （losses of 15N = 15N applied as fertilizer - 15N absorbed by crops - 15N remaining in the 0-0.2 m layer - 15N leached from the 1.3 m layer） in CU-treated plots were 24.2%-26.5% lower than those of NCU-treated plots. The nitrate concentration in the 0-1.3 m layer of CU plots at the end of the experiment was 53% lower than that of NCU-treated plots. Thus, CU increased crop N uptake from fertilizer and reduced unidentified losses of applied N, which can reduce the risk of groundwater pollution.展开更多
基金Supported by the Technology Development and Integration Model of Dairy Industry in Northwest of National Key Technology R&D Program(2006BAD04A11-06)during the Eleventh Five-Yearthe "Standardized Raising of Beef Cattle and Mutton Sheep" of the Eleventh Five-Year Major Projects in Autonomous Regions(200731135-2)+1 种基金the "Technology Development and Integration Model of Dairy Industry" of the Eleventh Five-Year Major Projects in Autonomous Regions(200731134)Science and Technology Projects for Green Food of Science and Technology Department of Xinjiang(200631107)~~
文摘[Objective] This study aimed to investigate the effects of three kinds of diuretics on the water drinking amount and urination volume of sheep fed with cottonseed hulls. [Method] The method of self-control was adopted. Five two-year-old male Kazak sheep about 40 kg which never had intake of the feeds containing gossypol were selected. The experiment was divided into five periods, namely the control period, a period with the supplement of 300 mg/d of hydrochlorothiazide, a period with the supplement of 200 mg/d of hydrochlorothiazide, a period with the supplement of 350 mg of GY-01 and a period with the supplement of 200 mg of GY-01. The sheep were fed with the concentrate and the cottonseed hulls in the control period, and corresponding diuretics were supplemented in the rest four periods. The water drinking amount, urination volume and the contents of the hormone and ion in the blood were determined in each period. [Result] After 350 mg GY-01 was supplemented, the water drinking amount of each sheep had an increase of 60.14% compared with that of the sheep in the control period and the urination volume was 2.67 times of that of the latter, and the differences were both significant （P0.01）. The antidiuretic hormone declined by 32.59% compared with that of the sheep in the control period, with the significant difference （P 0.05）. The adrenocorticotropic hormone content increased by 81.93% compared with that of the sheep in the control period and the difference was significant （P0.01）. An increase of 28.04% （P 0.05） and 39.39% （P 0.01） was found in the contents of serum potassium and phosphorus respectively compared with that of sheep in the control period. [Conclusion] The diet with supplement of GY-01 can increase the urination volume of livestock fed with the cottonseed hulls, and the most appropriate supplement amount is 200 mg GY-01.
文摘Background. Our previous studies indicated that the increased arginine vasopressin(AVP) in ischemic brain regions of gerbils could exacerbate the ischemic brain edema. This experiments is further clarify the relation between AVP and cerebral ischemia at the molecular level. Methods. The contents of AVP, AVP mRNA, AVP immunoreactive(ir) neurons in supraoptic nucleus(SON) and paraventricular nucleus(PVN) after cerebral ischemia and reperfusion were respectively determined by radioimmunoassay(RIA), immunocytochemistry(ⅡC), situ hybridization and computed image pattern analysis. Results. The contents of AVP in SON, PVN were increased, and the AVP ir positive neurons in SON and PVN were also significantly increased as compared with the controls after ischemia and reperfusion. And there were very light staining of AVP ir positive neurons in the other brain areas such as suprachiasmatic nucleus (SC) and periventricular hypothalamic nucleus (PE), but these have no significant changes as compared with the controls. During different periods of cerebral ischemia (30～120 min) and reperfusion (30 min), AVP mRNA expression in SON and PVN were more markedly increased than the controls. Conclusions. The transcription of AVP gene elevated, then promoting synthesis and release of AVP in SON, PVN. Under the specific condition of cerebral ischemia and reperfusion, the activity and contents of central AVP increased abnormally is one of the important factors which causes ischemia brain damage.
基金Project supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No.KZCX2-413-3)National Natural Science Foundation of China (No.30390080)National Basic Research Program of China (No.2005CB121108)
文摘Ammonia volatilization losses, nitrogen utilization efficiency, and rice yields in response to urea application to a rice field were investigated in Wangzhuang Town, Changshu City, Jiangsu Province, China. The N fertilizer treatments, applied in triplicate, were 0 （control）, 100, 200, 300, or 350 kg N ha^-1. After urea was applied to the surface water, a continuous airflow enclosure method was used to measure ammonia volatilization in the paddy field. Total N losses through ammonia volatilization generally increased with the N application rate, and the two higher N application rates （300 and 350 kg N ha^-1） showed a higher ratio of N lost through ammonia volatilization to applied N. Total ammonia loss by ammonia volatilization during the entire rice growth stage ranged from 9.0% to 16.7% of the applied N. Increasing the application rate generally decreased the ratio of N in the seed to N in the plant. For all N treatments, the nitrogen fertilizer utilization efficiency ranged from 30.9% to 45.9%. Surplus N with the highest N rate resulted in lodging of rice plants, a decreased rate of nitrogen fertilizer utilization, and reduced rice yields. Calculated from this experiment, the most economical N fertilizer application rate was 227 kg ha^-1 for the type of paddy soil in the Taihu Lake region. However, recommending an appropriate N fertilizer application rate such that the plant growth is enhanced and ammonia loss is reduced could improve the N utilization efficiency of rice.
文摘Spontaneous Ca2+ oscillations in vascular smooth muscle cells have been modeled using a single Ca2+ pool. This report describes spontaneous Ca2+ oscillations dependent on two separate Ca2+ sources for the nuclear versus cytoplas- mic compartments. Changes in free intracellular Ca2+ were monitored with ratiometric Ca2+- fluorophores using confo- cal microscopy. On average, spontaneous oscillations developed in 79% of rat aortic smooth muscle cells that were synchronous between the cytoplasm and nucleus. Reduction of extracellular Ca2+ (< 1 μM) decreased the frequency and amplitude of the cytoplasmic oscillations with 48% of the oscillations asynchronous between the nuclear and cytoplasmic compartments. Similar results were obtained with the Ca2+ channel blockers, nimodipine and diltiazem. Arg-vasopressin (AVP) induced a rapid release of intracellular Ca2+ stores that was greater in the nuclear compartment (4.20 ± 0.23 ratio units, n = 56) than cytoplasm (2.54 ± 0.28) in cells that had spontaneously developed prior oscillations. Conversely, cells in the same conditions lacking oscillations had a greater AVP-induced Ca2+ transient in the cytoplasm (4.99 ± 0.66, n = 17) than in the nucleus (2.67 ± 0.29). Pre-treatment with Ca2+ channel blockers depressed the AVP responses in both compartments with the cytoplasmic Ca2+ most diminished. Depletion of internal Ca2+ stores prior to AVP exposure blunted the nuclear response, mimicking the response of cells that lacked prior oscillations. Spontaneous oscillating cells had a greater sarcoplasmic reticulum network than cells that did not oscillate. We propose that sponta- neous nuclear oscillations rely on perinuclear sarcoplasmic reticulum stores, while the cytoplasmic oscillations rely on Ca2+ influx.
文摘Mongolian gerbils were used as delayed neuronal damage (DNDi animal models. At the end of 15Abstract:Mongolian gerbils were used as delayed neuronal damage (DND)animal models. At the end of 15 minute cerebral ischemia and at various reperfusion time ranging from 1 to 96 hours, the content of water and arginine vasopressin (AVP) in the CA1 sector of hippocampus were measured by the specific gravity method and radioimmunoassay. Furthermore, we also examined the effect of intracerebroventricular (ICV) injection of AVP, AVP antiserum on calcium, Na+, K+-ATPase activrty in the CA1 sector after ischemia and 96 hour reperfusion. The results showed that AVP contents of CA1 sector of hippocampus during 6 to 96 hour recirculation, and the water content of CA1 sector during 24 to 96 hour were significantly and continuously increased. After ICV inJection of AVP, the water content and calcium in CA1 sector of hippocampus at cerebral ischemia and 96 hour recirculation further increased, and the Na+, K+- ATPase activity in CA1 sector was remarkably decreased as compared with that of control. While ICV injection of AVP antiserum, the water content and calcium in CA1 sector were significantly decreased as com pared with that of control. These suggested that AVP was involved in the pathophysiologic process of DND in hippocampus following cerebral ischemia and reperfusion. Its mechanism might be through the change of intracellular action mediated by specific AVP receptor to lead to Ca ions over-load of neuron and inhibit the Na+, K+- ATPase activity , thereby to exacerbate the DND in hippocampus.
文摘Ascites is one of the major complications of liver cirrhosis and is associated with a poor prognosis. It is important to distinguish noncirrhotic from cirrhotic causes of ascites to guide therapy in patients with noncirrhotic ascites. Mild to moderate ascites is treated by salt restriction and diuretic therapy. The diuretic of choice is spironolactone. A combination treatment with furosemide might be necessary in patients who do not respond to spironolactone alone. Tense ascites is treated by paracentesis, followed by albumin infusion and diuretic therapy. Treatment options for refractory ascites include repeated paracentesis and transjugular intrahepatic portosystemic shunt placement in patients with a preserved liver function. Potential complications of ascites are spontaneous bacterial peritonitis (SBP) and hepatorenal syndrome (HRS). SBP is diagnosed by an ascitic neutrophil count > 250 cells/mm3 and is treated with antibiotics. Patients who survive a first episode of SBP or with a low protein concentration in the ascitic fluid require an antibiotic prophylaxis. The prognosis of untreated HRS type 1 is grave. Treatment consists of a combination of terlipressin and albumin. Hemodialysis might serve in selected patients as a bridging therapy to liver transplantation. Liver transplantation should be considered in all patients with ascites and liver cirrhosis.
文摘1,3-disubstituted ureas of adamantine series are potent for hypertension and inflammatory treatment. The most valuable parameters of these compounds are melting point and solubility. Higher melting point leads to lower bioavailability and for most of the compounds investigated before it was very high. Usage of isocyanates containing 1,3-dimethyladamantane fragment will significantly decrease the melting point, improve solubility and therefore improve bioavailability of 1,3-disubstituted ureas and other biologically active compounds produced on its base. This article presents new 1,3-disubstituted ureas and biureas synthesized by the authors.
文摘Objective： To evaluate plasma arginine vasopressin （AVP） level in patients with traumatic brain injury and investigate the role of AVP in the process of brain edema. Methods ： A total of 30 patients with traumatic brain injury were involved in our study. They were divided into two groups by Glasgow Coma Scale： severe tranmatic brain injury group （ STBI, GCS ≤ 8 ） and moderate traumatic brain injury group （ MTBI, GCS 〉 8 ）. Samples of venous blood were collected in the morning at rest from 15 healthy volunteers （control group）and within 24 h after traumatic brain injury from these patients for AVP determinations by radioimmunoassay. The severity and duration of the brain edema were estimated by head CT scan. Results： plasma AVP levels （ng/L） were （mean± SD） control, 3.06 ± 1.49; MTBI, 38. 12 ± 7. 25; andSTBI, 66. 61 ± 17. 10. The plasma level of AVP was significantly increased within 24 h after traumatic brain injury and followed by the reduction of GCS, suggesting the deterioration of cerebral injury （ P 〈 0.01 ）. And the AVP level was correlated with the severity （ STBI r = 0. 919, P 〈 0.01 ; MTBI r = 0. 724, P 〈 0.01 ） and the duration of brain edema （STBI r =0.790, P 〈0.01; MTBI r =0.712, P〈0.01）. Conclusions. The plasma AVP level is dosely associated with the severity of traumatic brain injury. AVP may play an important role in pathogenesis of brain edema after traumatic brain injury.
基金Supported by the National Basic Research Program (973 Program) of China (No. 2007CB109302)the Special Fund for Agro-Scientific Research in the Public Interest, China (No. 201103007)the Japan-China Co-operation Project
文摘The effectiveness of polyolefin-coated urea （Meister-5 and Meister-10; CU） in a wheat （Triticum aestivum L.）-maize （Zea mays L.） rotation system was studied in lysimeter plots located in the North China Plain for three consecutive maizewheat-maize cropping seasons. An isotopic method was used to compare the fate of CU to that of non-coated urea （NCU）, and N application rates of 0, 100, 150 and 225 kg N ha-1 were evaluated. The results showed that the nitrogen use efficiency （15NUE） of CU was 13.3%-21.4% greater than that of NCU for the first crop. Alternatively, when the difference method was applied （apparent NUE）, no significant variations were observed among treatments in all three seasons. Although inorganic N leached from the 1.3 m layer was less than 1% of the total applied N, unidentified losses of 15N （losses of 15N = 15N applied as fertilizer - 15N absorbed by crops - 15N remaining in the 0-0.2 m layer - 15N leached from the 1.3 m layer） in CU-treated plots were 24.2%-26.5% lower than those of NCU-treated plots. The nitrate concentration in the 0-1.3 m layer of CU plots at the end of the experiment was 53% lower than that of NCU-treated plots. Thus, CU increased crop N uptake from fertilizer and reduced unidentified losses of applied N, which can reduce the risk of groundwater pollution.
