In this paper, we consider a new Monod type chemostat model with time delay and impulsive input concentration of the nutrient in a polluted environment. Using the discrete dynamical system determined by the stroboscop...In this paper, we consider a new Monod type chemostat model with time delay and impulsive input concentration of the nutrient in a polluted environment. Using the discrete dynamical system determined by the stroboscopic map, we obtain a ＂microorganism-extinction＂ periodic solution. Further, we establish the sufficient conditions for the global attractivity of the microorganism-extinction periodic solution. Using new computational techniques for impulsive and delayed differential equation, we prove that the system is permanent under appropriate conditions. Our results show that time delay is ＂profitless＂.展开更多
OBJECTIVE To reveal the biological effects and effective dosage in radiotherapy model which applies high single-dose irradiation by animal experiment. METHODS We inoculated subcutaneouly human pancreatic carcinoma cel...OBJECTIVE To reveal the biological effects and effective dosage in radiotherapy model which applies high single-dose irradiation by animal experiment. METHODS We inoculated subcutaneouly human pancreatic carcinoma cell line （MIA PaCa-2） in the lateral of the right lower extremity of the athymic mouse to grow transplantation tumor. While the median diameter of transplantation tumor reached 10 mm approximately, the animals were randomly divided into 7 groups （6 animals per group） and irradiation by different dose in one fixed with consciousness for fraction （0, 2, 5, 10, 17, 25, 35 Gy）. All were kept on to be bred for observation of the change in gross tumor volume, calculation of delayed growth time and delayed growth curve. RESULTS With increased dose per fraction, cutaneous reaction on the neoplasma surface of the animal, which was mainly moist yellow effusion was more and more severe. When dosage is less than 10 Gy, all animals showed similar effects, that＇s the delayed tumor growth was not obvious. Tumors receiving more than 10 Gy in one fraction showed very good biological effect and the delayed tumor growth was obviously related to dosage. The difference in delayed tumor growth between the 2 groups was statistically significant. The delayed tumor growth time in 10, 17, 25 Gy group was respectively 3 weeks, 6 weeks and more. CONCLUSION The biological effect of the model which applies high single-dose irradiation （more than 10 Gy in one fraction） was very good. The effect of delayed tumor growth was obviously related to the dosage after transplantation tumor was radiated. Because of its higher dose per fraction and biological effects, the model of high single-dose irradiation can get better clinical effects.展开更多
Background： Delayed puberty can result either from constitutional delay of growth and puberty （CDP） or idiopathic hypogonadotropic hypogonadism （IHH）. Gonadotropin-releasing hormone （GnRH） stimulation test has ...Background： Delayed puberty can result either from constitutional delay of growth and puberty （CDP） or idiopathic hypogonadotropic hypogonadism （IHH）. Gonadotropin-releasing hormone （GnRH） stimulation test has been generally accepted as a current method for diagnosing delayed puberty. The objective of this research was to assess the cut-offvalues and the efficacy of GnRH stimulation test in the diagnosis of delayed puberty in both males and females. Methods： A study of 91 IHH, 27 CDP patients, 6 prepubertal children, and 20 pubertal adults was undertaken. Blood samples were obtained at 0, 30, 60, and 120 rain after GnRH administration and the levels of luteinizing hormone （LH） and follicle-stimulating hormone （FSH） were rneast, red. For each paralneter, the sensitivities and specificities were estimated, and the receiver operating characteristic （ROC） curves were constructed. Resulis： The ROC curves indicated that a serunl basal LH 〈0.6 IU/L or peak LH 〈9.74 IU/L resulted in moderate sensitivity （73.8% or 80.0%） and specificity （90.9% or 86.4%） in the diagnosis of HH in males. Serum basal LH 〈0.85 IU/L or basal FSH 〈2.43 IU/L resulted in moderate sensitivity （80.0% or 100.0%） and specificity （75.0% or 50.0%） in the diagnosis of HH in females. Conclusions： Our data suggest that isolated use of the gonadorelin stimulation test is almost sufficient to discriminate between HH and CDP in males, but unnecessary in females. The most useful predictor is serum basal or peak LH to differentiate these two disorders in males, but serum basal LH or FSH in females.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.10471117 and 10771179)the Natural Science Foundation of Shandong University of Science and Technology(No.05g016)
文摘In this paper, we consider a new Monod type chemostat model with time delay and impulsive input concentration of the nutrient in a polluted environment. Using the discrete dynamical system determined by the stroboscopic map, we obtain a ＂microorganism-extinction＂ periodic solution. Further, we establish the sufficient conditions for the global attractivity of the microorganism-extinction periodic solution. Using new computational techniques for impulsive and delayed differential equation, we prove that the system is permanent under appropriate conditions. Our results show that time delay is ＂profitless＂.
文摘OBJECTIVE To reveal the biological effects and effective dosage in radiotherapy model which applies high single-dose irradiation by animal experiment. METHODS We inoculated subcutaneouly human pancreatic carcinoma cell line （MIA PaCa-2） in the lateral of the right lower extremity of the athymic mouse to grow transplantation tumor. While the median diameter of transplantation tumor reached 10 mm approximately, the animals were randomly divided into 7 groups （6 animals per group） and irradiation by different dose in one fixed with consciousness for fraction （0, 2, 5, 10, 17, 25, 35 Gy）. All were kept on to be bred for observation of the change in gross tumor volume, calculation of delayed growth time and delayed growth curve. RESULTS With increased dose per fraction, cutaneous reaction on the neoplasma surface of the animal, which was mainly moist yellow effusion was more and more severe. When dosage is less than 10 Gy, all animals showed similar effects, that＇s the delayed tumor growth was not obvious. Tumors receiving more than 10 Gy in one fraction showed very good biological effect and the delayed tumor growth was obviously related to dosage. The difference in delayed tumor growth between the 2 groups was statistically significant. The delayed tumor growth time in 10, 17, 25 Gy group was respectively 3 weeks, 6 weeks and more. CONCLUSION The biological effect of the model which applies high single-dose irradiation （more than 10 Gy in one fraction） was very good. The effect of delayed tumor growth was obviously related to the dosage after transplantation tumor was radiated. Because of its higher dose per fraction and biological effects, the model of high single-dose irradiation can get better clinical effects.
文摘Background： Delayed puberty can result either from constitutional delay of growth and puberty （CDP） or idiopathic hypogonadotropic hypogonadism （IHH）. Gonadotropin-releasing hormone （GnRH） stimulation test has been generally accepted as a current method for diagnosing delayed puberty. The objective of this research was to assess the cut-offvalues and the efficacy of GnRH stimulation test in the diagnosis of delayed puberty in both males and females. Methods： A study of 91 IHH, 27 CDP patients, 6 prepubertal children, and 20 pubertal adults was undertaken. Blood samples were obtained at 0, 30, 60, and 120 rain after GnRH administration and the levels of luteinizing hormone （LH） and follicle-stimulating hormone （FSH） were rneast, red. For each paralneter, the sensitivities and specificities were estimated, and the receiver operating characteristic （ROC） curves were constructed. Resulis： The ROC curves indicated that a serunl basal LH 〈0.6 IU/L or peak LH 〈9.74 IU/L resulted in moderate sensitivity （73.8% or 80.0%） and specificity （90.9% or 86.4%） in the diagnosis of HH in males. Serum basal LH 〈0.85 IU/L or basal FSH 〈2.43 IU/L resulted in moderate sensitivity （80.0% or 100.0%） and specificity （75.0% or 50.0%） in the diagnosis of HH in females. Conclusions： Our data suggest that isolated use of the gonadorelin stimulation test is almost sufficient to discriminate between HH and CDP in males, but unnecessary in females. The most useful predictor is serum basal or peak LH to differentiate these two disorders in males, but serum basal LH or FSH in females.
