The exploitation of renewable resources creates many complex problems for culture, ecology and economics as well. Ascertaining the essentials behind the coraplex problems is very important, in this paper, we mainly st...The exploitation of renewable resources creates many complex problems for culture, ecology and economics as well. Ascertaining the essentials behind the coraplex problems is very important, in this paper, we mainly study various complex relations appearing in the optimal exploitation process for renewable resources. First, we derive a sufficient condition on the existence of optimal harvesting policies for one-species population resources. Then we present every possible optimal harvesting pattern for such a modeh On the basis of this, we give a computing formula for estimating the optimal harvesting period, optimal transitional period, and optimal recruitment period. The main difference with respect to the previous works in literature is that our optimal harvesting policy is a piece-wise continuous function of time t, at the piecewise point to, which is called switching time. At the switching time we switch the harvesting rate from h to some transitional control u,, then to 0. Clearly this kind of harvesting policy is easier to carry out than those by others, provided that there exists a managing department which can highly supervise the resources.展开更多
To repair the blood–brain barrier(BBB)after traumatic brain injury(TBI)remains a multidisciplinary challenge.No first-line drugs are available.Here,we reported a novel and non-toxic functional negative-charged carbon...To repair the blood–brain barrier(BBB)after traumatic brain injury(TBI)remains a multidisciplinary challenge.No first-line drugs are available.Here,we reported a novel and non-toxic functional negative-charged carbon dots(CDs)generated from green Semen pruni persicae and Carthamus tinctorius L.(TH-CDs)through a hydrothermal synthesis without any organic solvent.The surface of TH-CDs retained part functional groups of active pharmacophores from both drugs.TH-CDs could improve the neurological function,brain edema,neuronal damage,and the BBB permeability by tail vein injection of mice models without systemic toxicity.Furthermore,higher expression of tight junction proteins claudin 5 and ZO-1 was observed after TH-CDs administration,which may be due to the electrostatic interaction between TH-CDs and claudin 5.Our study highlights an inexpensive,green,non-toxic,and intravenous functional TH-CD,which represents a potential TBI treatment strategy.展开更多
基金This Work is supported by National Natural Science Fund of China Under Grant No.70271066
文摘The exploitation of renewable resources creates many complex problems for culture, ecology and economics as well. Ascertaining the essentials behind the coraplex problems is very important, in this paper, we mainly study various complex relations appearing in the optimal exploitation process for renewable resources. First, we derive a sufficient condition on the existence of optimal harvesting policies for one-species population resources. Then we present every possible optimal harvesting pattern for such a modeh On the basis of this, we give a computing formula for estimating the optimal harvesting period, optimal transitional period, and optimal recruitment period. The main difference with respect to the previous works in literature is that our optimal harvesting policy is a piece-wise continuous function of time t, at the piecewise point to, which is called switching time. At the switching time we switch the harvesting rate from h to some transitional control u,, then to 0. Clearly this kind of harvesting policy is easier to carry out than those by others, provided that there exists a managing department which can highly supervise the resources.
基金supported by the National Natural Science Foundation of China(No.81973665)the Science and Technology Innovation Program of Hunan Province(No.2021RC3030)+1 种基金the Fundamental Research Funds for the Central Universities of Central South University(No.2021zzts1028)the InnovationDriven Project of Central South University(No.2020CX047).
文摘To repair the blood–brain barrier(BBB)after traumatic brain injury(TBI)remains a multidisciplinary challenge.No first-line drugs are available.Here,we reported a novel and non-toxic functional negative-charged carbon dots(CDs)generated from green Semen pruni persicae and Carthamus tinctorius L.(TH-CDs)through a hydrothermal synthesis without any organic solvent.The surface of TH-CDs retained part functional groups of active pharmacophores from both drugs.TH-CDs could improve the neurological function,brain edema,neuronal damage,and the BBB permeability by tail vein injection of mice models without systemic toxicity.Furthermore,higher expression of tight junction proteins claudin 5 and ZO-1 was observed after TH-CDs administration,which may be due to the electrostatic interaction between TH-CDs and claudin 5.Our study highlights an inexpensive,green,non-toxic,and intravenous functional TH-CD,which represents a potential TBI treatment strategy.
