作为新型海洋污染物,海洋塑料垃圾入海通量计算过程中涉及的源汇过程、迁移途径、输运过程等尚未完全清楚,需进一步研究完善。以工业高速发展的厦门湾为研究对象,考虑潮流、入海径流、风等因素的影响,基于MIKE3软件的生物仿真模拟技术(A...作为新型海洋污染物,海洋塑料垃圾入海通量计算过程中涉及的源汇过程、迁移途径、输运过程等尚未完全清楚,需进一步研究完善。以工业高速发展的厦门湾为研究对象,考虑潮流、入海径流、风等因素的影响,基于MIKE3软件的生物仿真模拟技术(Agent Based Modelling),模拟研究了漂浮及悬浮塑料垃圾的分布特征和迁移规律,并提出经验公式对沉积塑料垃圾的通量进行了预测。结果表明漂浮塑料垃圾在不利风、常风向和最大风的作用下集中堆积于岸线处。而悬浮塑料垃圾由海面向下呈现指数式下降的分布特征,且其水平迁移分布与潮流运动密切相关;流速小的区域悬浮塑料垃圾更容易堆积使局部浓度升高。悬浮塑料垃圾的扩散速率也与塑料颗粒的物理性质有关,沉降速度小的塑料颗粒在水中悬浮的时间更长,更容易被传输到距离污染源更远的地方。同时,研究发现沉积微塑料通量的增长规律近似为线性变化,通量大小与厦门塑料产量和厦门湾的水动力特性相关。展开更多
Rising worldwide cancer incidence and resistance to current anti-cancer drugs necessitate the need for new pharmaceutical compounds and drug delivery system. Malfunction of the immune system, particularly in the tumor...Rising worldwide cancer incidence and resistance to current anti-cancer drugs necessitate the need for new pharmaceutical compounds and drug delivery system. Malfunction of the immune system, particularly in the tumor microenvironment, causes tumor growth and enhances tumor progression. Thus, cancer immunotherapy can be an appropriate approach to provoke the systemic immune system to combat tumor expansion. Texosomesj which are endogenous nanovesicles released by all tumor cells, contribute to cell-cell communication and modify the phenotypic features of recipient cells due to the texosomes＇ ability to transport biological components. For this reason, texosome-based delivery system can be a valuable strategy for therapeutic purposes. To improve the pharmaceutical behavior of this system and to facilitate its use in medical applications, biotechnology approaches and mimetic techniques have been utilized. In this review, we present the development history oftexosome-based delivery systems and discuss the advantages and disadvantages of each system.展开更多
The motion of small bacteria consists of two phases:relatively long runs alternate with intermittent stops,back-ups,or tumbles,depending on the species.In polar monotrichous bacteria,the flagellum is anchored at the c...The motion of small bacteria consists of two phases:relatively long runs alternate with intermittent stops,back-ups,or tumbles,depending on the species.In polar monotrichous bacteria,the flagellum is anchored at the cell pole inherited from the parent generation(old pole) and is surrounded by a chemoreceptor cluster.During forward swimming,the leading pole is always the pole recently formed in cell division(new pole).The flagella of the peritrichous bacterium Escherichia coli often form a bundle behind the old pole.Its cell orientation and receptor positioning during runs generally mimic that of monotrichous bacteria.When encountering a solid surface,peritrichous bacteria exhibit a circular motion with the leading pole dipping downward.Some polar monotrichous bacteria also perform circular motion near solid boundaries,but during back-ups.In this case,the leading pole points upward.Very little is known about behavior near milieu-air interfaces.Biophysical simulations have revealed some of the mechanisms underlying these phenomena,but leave many questions unanswered.Combining biophysics with molecular techniques will certainly advance our understanding of bacterial locomotion.展开更多
文摘作为新型海洋污染物,海洋塑料垃圾入海通量计算过程中涉及的源汇过程、迁移途径、输运过程等尚未完全清楚,需进一步研究完善。以工业高速发展的厦门湾为研究对象,考虑潮流、入海径流、风等因素的影响,基于MIKE3软件的生物仿真模拟技术(Agent Based Modelling),模拟研究了漂浮及悬浮塑料垃圾的分布特征和迁移规律,并提出经验公式对沉积塑料垃圾的通量进行了预测。结果表明漂浮塑料垃圾在不利风、常风向和最大风的作用下集中堆积于岸线处。而悬浮塑料垃圾由海面向下呈现指数式下降的分布特征,且其水平迁移分布与潮流运动密切相关;流速小的区域悬浮塑料垃圾更容易堆积使局部浓度升高。悬浮塑料垃圾的扩散速率也与塑料颗粒的物理性质有关,沉降速度小的塑料颗粒在水中悬浮的时间更长,更容易被传输到距离污染源更远的地方。同时,研究发现沉积微塑料通量的增长规律近似为线性变化,通量大小与厦门塑料产量和厦门湾的水动力特性相关。
文摘Rising worldwide cancer incidence and resistance to current anti-cancer drugs necessitate the need for new pharmaceutical compounds and drug delivery system. Malfunction of the immune system, particularly in the tumor microenvironment, causes tumor growth and enhances tumor progression. Thus, cancer immunotherapy can be an appropriate approach to provoke the systemic immune system to combat tumor expansion. Texosomesj which are endogenous nanovesicles released by all tumor cells, contribute to cell-cell communication and modify the phenotypic features of recipient cells due to the texosomes＇ ability to transport biological components. For this reason, texosome-based delivery system can be a valuable strategy for therapeutic purposes. To improve the pharmaceutical behavior of this system and to facilitate its use in medical applications, biotechnology approaches and mimetic techniques have been utilized. In this review, we present the development history oftexosome-based delivery systems and discuss the advantages and disadvantages of each system.
文摘The motion of small bacteria consists of two phases:relatively long runs alternate with intermittent stops,back-ups,or tumbles,depending on the species.In polar monotrichous bacteria,the flagellum is anchored at the cell pole inherited from the parent generation(old pole) and is surrounded by a chemoreceptor cluster.During forward swimming,the leading pole is always the pole recently formed in cell division(new pole).The flagella of the peritrichous bacterium Escherichia coli often form a bundle behind the old pole.Its cell orientation and receptor positioning during runs generally mimic that of monotrichous bacteria.When encountering a solid surface,peritrichous bacteria exhibit a circular motion with the leading pole dipping downward.Some polar monotrichous bacteria also perform circular motion near solid boundaries,but during back-ups.In this case,the leading pole points upward.Very little is known about behavior near milieu-air interfaces.Biophysical simulations have revealed some of the mechanisms underlying these phenomena,but leave many questions unanswered.Combining biophysics with molecular techniques will certainly advance our understanding of bacterial locomotion.
