Prochlorococcus is the dominant population of the autotrophs in the oceanic area in theSouth China Sea; and contributes significantly to picoplanktonic (【2μm) carbon biomass. However, thereis no availabe data on its...Prochlorococcus is the dominant population of the autotrophs in the oceanic area in theSouth China Sea; and contributes significantly to picoplanktonic (【2μm) carbon biomass. However, thereis no availabe data on its growth the and productivity so far. In the present study, the in situ populationgrowth rate of Prochlorococus at the chlorophyll maximum layer at 6 .3°N, 110°E in the South China展开更多
The therapeutic options for patients with metastatic renal cell carcinoma(mRCC) have completely changed during the last ten years. With the sequential use of targeted therapies, median overall survival has increased i...The therapeutic options for patients with metastatic renal cell carcinoma(mRCC) have completely changed during the last ten years. With the sequential use of targeted therapies, median overall survival has increased in daily practice and now it is not uncommon to see patients surviving kidney cancer for more than four to five years. Once treatment fails with the first line targeted therapy, head to head comparisons have shown that cabozantinib, nivolumab and the combination of lenvatinib plus everolimus are more effective than everolimus alone and that axitinib is more active than sorafenib. Unfortunately, it is very unlikely that we will ever have prospective data comparing the activity of axitinib, cabozantinib, lenvatinib or nivolumab. It is frustrating to observe the lack of biomarkers that we have in this field, thus there is no firm recommendation about the optimal sequence of treatment in the second line. In the absence of reliable biomarkers, there are several clinical endpoints that can help physicians to make decisions for an individual patient, such as the tumor burden, the expected response rate and the time to achieve the response to each agent, the prior response to the agent administered, the toxicity profile of the different compounds and patient preference. Here, we propose the introduction of the tumor-growth rate(TGR) during first-line treatment as a new tool to be used to select the second line strategy in m RCC. The rapidness of TGR before the onset of the treatment reflects the variability between patients in terms of tumor growth kinetics and it could be a surrogate marker of tumor aggressiveness that may guide treatment decisions.展开更多
The maximum growth rate of Nitzschia closterium at various concentrations of petroleum hydrocarbon was studied. The influence of petroleum hydrocarbon on cell size as a function of concentration was discussed. The rel...The maximum growth rate of Nitzschia closterium at various concentrations of petroleum hydrocarbon was studied. The influence of petroleum hydrocarbon on cell size as a function of concentration was discussed. The relationship between maximum growth rate of Nitzschia closterium and cell median equivalent spherical diameter (MESD) was also carefully studied. The experimental results showed that the growth rate of Nitzschia closterium was generally suppressed by petroleum hydrocarbon, which had greater effects at both low and high concentrations than at intermediate concentrations. No significant changes in cell size distribution were observed during the growth period of Nitzschia closterium. The Gaussian function could give a clear description of the cell size distribution of Nitzschia closterium, and the MESD value ranged from 2.71 to 6.82 μm. The MESD decreased when the cell was exposed to petroleum hydrocarbon, and the reduction of cell MESD was much more significant at both relatively high and low hydrocarbon concentrations. The presence of petroleum hydrocarbon changed the relationship between μmax and MESD from an allometric function to a U-shaped curve. When the MESD was below 5.07 μm, μmax decreased along with increased MESD, whereas when MESD was above 5.07 μm, μmax increased along with MESD, which deviated from the allometric model.展开更多
The understanding of the macroscopic phenomenological models of the population growth at a microscopic level is important to predict the population behaviors emerged from the interactions between the individuals. In t...The understanding of the macroscopic phenomenological models of the population growth at a microscopic level is important to predict the population behaviors emerged from the interactions between the individuals. In this work, we consider the influence of the population growth rate R on the cell-cell interaction in a tumor system and show that, in most cases especially small proliferative probabilities, the regulative role of the interaction will be strengthened with the decline of the intrinsic proliferative probabilities. For the high replication rates of an individual and the cooperative interactions, the proliferative probability almost has no effect. We compute the dependences of R on the interactions between the cells under the approximation of the nearest neighbor in the rim of an avascular tumor. Our results are helpful to qualitatively understand the influence of the interactions between the individuals on the growth rate in population systems.展开更多
基金This study was supported by the 973 Project No.G2000078500,863 Project No.2001AA630509-2,NSFC Project No.4O232021,30170189 and 4017603
文摘Prochlorococcus is the dominant population of the autotrophs in the oceanic area in theSouth China Sea; and contributes significantly to picoplanktonic (【2μm) carbon biomass. However, thereis no availabe data on its growth the and productivity so far. In the present study, the in situ populationgrowth rate of Prochlorococus at the chlorophyll maximum layer at 6 .3°N, 110°E in the South China
文摘The therapeutic options for patients with metastatic renal cell carcinoma(mRCC) have completely changed during the last ten years. With the sequential use of targeted therapies, median overall survival has increased in daily practice and now it is not uncommon to see patients surviving kidney cancer for more than four to five years. Once treatment fails with the first line targeted therapy, head to head comparisons have shown that cabozantinib, nivolumab and the combination of lenvatinib plus everolimus are more effective than everolimus alone and that axitinib is more active than sorafenib. Unfortunately, it is very unlikely that we will ever have prospective data comparing the activity of axitinib, cabozantinib, lenvatinib or nivolumab. It is frustrating to observe the lack of biomarkers that we have in this field, thus there is no firm recommendation about the optimal sequence of treatment in the second line. In the absence of reliable biomarkers, there are several clinical endpoints that can help physicians to make decisions for an individual patient, such as the tumor burden, the expected response rate and the time to achieve the response to each agent, the prior response to the agent administered, the toxicity profile of the different compounds and patient preference. Here, we propose the introduction of the tumor-growth rate(TGR) during first-line treatment as a new tool to be used to select the second line strategy in m RCC. The rapidness of TGR before the onset of the treatment reflects the variability between patients in terms of tumor growth kinetics and it could be a surrogate marker of tumor aggressiveness that may guide treatment decisions.
基金supported by the Chinese National Programs for High Technology Research and Development (No.2007AA09Z106).
文摘The maximum growth rate of Nitzschia closterium at various concentrations of petroleum hydrocarbon was studied. The influence of petroleum hydrocarbon on cell size as a function of concentration was discussed. The relationship between maximum growth rate of Nitzschia closterium and cell median equivalent spherical diameter (MESD) was also carefully studied. The experimental results showed that the growth rate of Nitzschia closterium was generally suppressed by petroleum hydrocarbon, which had greater effects at both low and high concentrations than at intermediate concentrations. No significant changes in cell size distribution were observed during the growth period of Nitzschia closterium. The Gaussian function could give a clear description of the cell size distribution of Nitzschia closterium, and the MESD value ranged from 2.71 to 6.82 μm. The MESD decreased when the cell was exposed to petroleum hydrocarbon, and the reduction of cell MESD was much more significant at both relatively high and low hydrocarbon concentrations. The presence of petroleum hydrocarbon changed the relationship between μmax and MESD from an allometric function to a U-shaped curve. When the MESD was below 5.07 μm, μmax decreased along with increased MESD, whereas when MESD was above 5.07 μm, μmax increased along with MESD, which deviated from the allometric model.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11675008 and 21434001
文摘The understanding of the macroscopic phenomenological models of the population growth at a microscopic level is important to predict the population behaviors emerged from the interactions between the individuals. In this work, we consider the influence of the population growth rate R on the cell-cell interaction in a tumor system and show that, in most cases especially small proliferative probabilities, the regulative role of the interaction will be strengthened with the decline of the intrinsic proliferative probabilities. For the high replication rates of an individual and the cooperative interactions, the proliferative probability almost has no effect. We compute the dependences of R on the interactions between the cells under the approximation of the nearest neighbor in the rim of an avascular tumor. Our results are helpful to qualitatively understand the influence of the interactions between the individuals on the growth rate in population systems.
