This paper is to investigate a variable-coefficient modified Kortweg-de Vries （vc-mKdV） model, which describes some situations from fluid mechanics, ocean dynamics, and plasma mechanics. By the AblowRz-Kaup-NewellSe...This paper is to investigate a variable-coefficient modified Kortweg-de Vries （vc-mKdV） model, which describes some situations from fluid mechanics, ocean dynamics, and plasma mechanics. By the AblowRz-Kaup-NewellSegur procedure and symbolic computation, the Lax pair of the vc-MKdV model is derived. Then, based on the aforementioned Lax pair, the Darboux transformation is constructed and a new one-soliton-like solution is obtained as weft Features of the one-soliton-like solution are analyzed and graphically discussed to illustrate the influence of the variable coefficients in the solitonlike propagation.展开更多
AIM To assess the efficiency of endoscopic trans-esophageal submucosal tunneling surgery(EESTS) technique for diseases located around the aorta ventralis.METHODS Nine pigs were assigned to EESTs. The procedures were a...AIM To assess the efficiency of endoscopic trans-esophageal submucosal tunneling surgery(EESTS) technique for diseases located around the aorta ventralis.METHODS Nine pigs were assigned to EESTs. The procedures were as follows: First, a long esophageal submucosal tunnel was established. Second, full-thickness myotomy was created. Third, an endoscope was entered into the abdominal cavity through a muscle incision and the endoscope was around the aorta ventralis. Eventually,celiac trunk ganglion neurolysis, partial hepatectomy and splenectomy, partial tissue resection in the area of the posterior peritoneum, and endoscopic submucosal dissection(ESD) combined with lymph node dissection were performed. The animals were given antibiotics for 5 d and necropsied 7 d after surgery.RESULTS In all surgeries, one pig died from intraperitoneal hemorrhage after doing partial splenectomy, while the other pigs were alive after successfully operating other surgeries. For surgery of celiac trunk ganglion damage, at necropsy, there was no exudation in the abdominal cavity. Regarding surgery of partial hepatectomy, the wound with part healing was observed in the left hepatic lobe, and no bleeding or obvious exudation was seen. In surgery of partial splenectomy, massive hemorrhage was observed on the splenic wound surface, and the metal clips could not stop bleeding. After surgery of retroperitoneal tissue resection, mild tissue adhesion was observed in the abdominal cavity of one animal, and another one suffered from severe infection. For surgery of ESD and lymph node dissection, a moderate tissue adhesion was observed.CONCLUSION EESTS is a feasible and safe technique for diseases located around the aorta ventralis.展开更多
Locoregional treatments(LRT) represent a broad strategy used for reducing the risk of drop-off and contextually improving the survivals in patients with hepatocellular cancer receiving a liver transplantation(LT). How...Locoregional treatments(LRT) represent a broad strategy used for reducing the risk of drop-off and contextually improving the survivals in patients with hepatocellular cancer receiving a liver transplantation(LT). However, it is not sufficiently clear if LRT are only a surrogate of tumor aggressiveness or if they consent a real benefit in terms of tumor stabilization. A recent study by Pommergaard et al reported the results from the European Liver Transplant Registry. Patients receiving LRT before LT had better 5-year survival rates respect to no-LRT cases(69.7% vs 65.8%; P < 0.001). When the number of LRT was tested, one-to-two treatments were connected with improved survivals respect to no treatment [hazard ratio(HR) = 0.85 and 0.71, respectively]. The efficacy of LRT was also reported in the presence of larger tumors(HR = 0.78) and micro-macrovascular invasion(HR = 0.71). The results observed in the present study are partially in discordance with other analyses showing a detrimental effect of LRT. The main problem in the interpretation of these results is connected with the possible initial selection biases present in the studies. The most recent guidelines suggest to perform LRT before the transplant, but the level of evidence is typically low due to the absence of prospectively designed studies.展开更多
The notion that animals could be used as predictive models in science has been influenced by relatively recent developments in the fields of complexity science, evolutionary and developmental biology, genetics, and ev...The notion that animals could be used as predictive models in science has been influenced by relatively recent developments in the fields of complexity science, evolutionary and developmental biology, genetics, and evolutionary biology in general. Combined with empirical evidence, which has led scientists in drug development to acknowledge that a new, nonanimal model is needed, a theory—not a hypothesis—has been formed to explain why animals function well as models for humans at lower levels of organization but are unable to predict outcomes at higher levels of organization. Trans-Species Modeling Theory (TSMT) places the empirical evidence in the context of a scientific theory and thus, from a scientific perspective, the issue of where animals can and cannot be used in science has arguably been settled. Yet, some in various areas of science or science-related fields continue to demand that more evidence be offered before the use of animal models in medical research and testing be abandoned on scientific grounds. In this article, I examine TSMT, the empirical evidence surrounding the use of animal models, and the opinions of experts. I contrast these facts with the opinions and positions of those that have a direct or indirect vested interest—financial or otherwise—in animal models. I then discuss the ethical implications regarding research constructed to find cures and treatments for humans.展开更多
The so-called “global polytropic model” is based on the assumption of hydrostatic equilibrium for the solar system, or for a planet’s system of statellites (like the Jovian system), described by the Lane-Emden diff...The so-called “global polytropic model” is based on the assumption of hydrostatic equilibrium for the solar system, or for a planet’s system of statellites (like the Jovian system), described by the Lane-Emden differential equation. A polytropic sphere of polytropic index?n?and radius?R1?represents the central component?S1?(Sun or planet) of a polytropic configuration with further components the polytropic spherical shells?S2,?S3,?..., defined by the pairs of radi (R1,?R2), (R2,?R3),?..., respectively.?R1,?R2,?R3,?..., are the roots of the real part Re(θ) of the complex Lane-Emden function?θ. Each polytropic shell is assumed to be an appropriate place for a planet, or a planet’s satellite, to be “born” and “live”. This scenario has been studied numerically for the cases of the solar and the Jovian systems. In the present paper, the Lane-Emden differential equation is solved numerically in the complex plane by using the Fortran code DCRKF54 (modified Runge-Kutta-Fehlberg code of fourth and fifth order for solving initial value problems in the complex plane along complex paths). We include in our numerical study some trans-Neptunian objects.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No. 60772023by the Open Fund of the State Key Laboratory of Software Development Environment under Grant No. BUAA-SKLSDE-09KF-04+1 种基金Beijing University of Aeronautics and Astronautics, by the National Basic Research Program of China (973 Program) under Grant No. 2005CB321901by the Specialized Research Fund for the Doctoral Program of Higher Education under Grant Nos. 20060006024 and 200800130006, Chinese Ministry of Education
文摘This paper is to investigate a variable-coefficient modified Kortweg-de Vries （vc-mKdV） model, which describes some situations from fluid mechanics, ocean dynamics, and plasma mechanics. By the AblowRz-Kaup-NewellSegur procedure and symbolic computation, the Lax pair of the vc-MKdV model is derived. Then, based on the aforementioned Lax pair, the Darboux transformation is constructed and a new one-soliton-like solution is obtained as weft Features of the one-soliton-like solution are analyzed and graphically discussed to illustrate the influence of the variable coefficients in the solitonlike propagation.
基金Scientific Research Support Fund for Chinese PLA General Hospital,No.2012FCTSYS-3035
文摘AIM To assess the efficiency of endoscopic trans-esophageal submucosal tunneling surgery(EESTS) technique for diseases located around the aorta ventralis.METHODS Nine pigs were assigned to EESTs. The procedures were as follows: First, a long esophageal submucosal tunnel was established. Second, full-thickness myotomy was created. Third, an endoscope was entered into the abdominal cavity through a muscle incision and the endoscope was around the aorta ventralis. Eventually,celiac trunk ganglion neurolysis, partial hepatectomy and splenectomy, partial tissue resection in the area of the posterior peritoneum, and endoscopic submucosal dissection(ESD) combined with lymph node dissection were performed. The animals were given antibiotics for 5 d and necropsied 7 d after surgery.RESULTS In all surgeries, one pig died from intraperitoneal hemorrhage after doing partial splenectomy, while the other pigs were alive after successfully operating other surgeries. For surgery of celiac trunk ganglion damage, at necropsy, there was no exudation in the abdominal cavity. Regarding surgery of partial hepatectomy, the wound with part healing was observed in the left hepatic lobe, and no bleeding or obvious exudation was seen. In surgery of partial splenectomy, massive hemorrhage was observed on the splenic wound surface, and the metal clips could not stop bleeding. After surgery of retroperitoneal tissue resection, mild tissue adhesion was observed in the abdominal cavity of one animal, and another one suffered from severe infection. For surgery of ESD and lymph node dissection, a moderate tissue adhesion was observed.CONCLUSION EESTS is a feasible and safe technique for diseases located around the aorta ventralis.
文摘Locoregional treatments(LRT) represent a broad strategy used for reducing the risk of drop-off and contextually improving the survivals in patients with hepatocellular cancer receiving a liver transplantation(LT). However, it is not sufficiently clear if LRT are only a surrogate of tumor aggressiveness or if they consent a real benefit in terms of tumor stabilization. A recent study by Pommergaard et al reported the results from the European Liver Transplant Registry. Patients receiving LRT before LT had better 5-year survival rates respect to no-LRT cases(69.7% vs 65.8%; P < 0.001). When the number of LRT was tested, one-to-two treatments were connected with improved survivals respect to no treatment [hazard ratio(HR) = 0.85 and 0.71, respectively]. The efficacy of LRT was also reported in the presence of larger tumors(HR = 0.78) and micro-macrovascular invasion(HR = 0.71). The results observed in the present study are partially in discordance with other analyses showing a detrimental effect of LRT. The main problem in the interpretation of these results is connected with the possible initial selection biases present in the studies. The most recent guidelines suggest to perform LRT before the transplant, but the level of evidence is typically low due to the absence of prospectively designed studies.
文摘The notion that animals could be used as predictive models in science has been influenced by relatively recent developments in the fields of complexity science, evolutionary and developmental biology, genetics, and evolutionary biology in general. Combined with empirical evidence, which has led scientists in drug development to acknowledge that a new, nonanimal model is needed, a theory—not a hypothesis—has been formed to explain why animals function well as models for humans at lower levels of organization but are unable to predict outcomes at higher levels of organization. Trans-Species Modeling Theory (TSMT) places the empirical evidence in the context of a scientific theory and thus, from a scientific perspective, the issue of where animals can and cannot be used in science has arguably been settled. Yet, some in various areas of science or science-related fields continue to demand that more evidence be offered before the use of animal models in medical research and testing be abandoned on scientific grounds. In this article, I examine TSMT, the empirical evidence surrounding the use of animal models, and the opinions of experts. I contrast these facts with the opinions and positions of those that have a direct or indirect vested interest—financial or otherwise—in animal models. I then discuss the ethical implications regarding research constructed to find cures and treatments for humans.
文摘The so-called “global polytropic model” is based on the assumption of hydrostatic equilibrium for the solar system, or for a planet’s system of statellites (like the Jovian system), described by the Lane-Emden differential equation. A polytropic sphere of polytropic index?n?and radius?R1?represents the central component?S1?(Sun or planet) of a polytropic configuration with further components the polytropic spherical shells?S2,?S3,?..., defined by the pairs of radi (R1,?R2), (R2,?R3),?..., respectively.?R1,?R2,?R3,?..., are the roots of the real part Re(θ) of the complex Lane-Emden function?θ. Each polytropic shell is assumed to be an appropriate place for a planet, or a planet’s satellite, to be “born” and “live”. This scenario has been studied numerically for the cases of the solar and the Jovian systems. In the present paper, the Lane-Emden differential equation is solved numerically in the complex plane by using the Fortran code DCRKF54 (modified Runge-Kutta-Fehlberg code of fourth and fifth order for solving initial value problems in the complex plane along complex paths). We include in our numerical study some trans-Neptunian objects.
