In evolutionary genetics, Muller's ratchet (named after Hermann Joseph Muller, by analogy with a ratchet effect) is a process in which absence of recombination, especially in an asexual population, results in accumulation of deleterious mutations (harmful mutations) in an irreversible manner.
Sexual dimorphism is the condition where the two sexes of the same species exhibit different characteristics beyond the differences in their sexual organs. The condition occurs in many animals and some plants.
对我6+年的phd只有两个诉求
1. 英语太烂了，想要英语尽量close to native，能够自由地表达自己的情感，以及和别人自在地讨论research
2. 尽量knowledgable in biology especially in my field，能够自信地给别人解答问题，对biology有自己地见解和追求
别的真的无所谓
1. 英语太烂了，想要英语尽量close to native，能够自由地表达自己的情感，以及和别人自在地讨论research
2. 尽量knowledgable in biology especially in my field，能够自信地给别人解答问题，对biology有自己地见解和追求
别的真的无所谓
多维标度（Multidimensional scaling，缩写MDS，又译“多维尺度”）也称作“相似度结构分析”（Similarity structure analysis），属于多重变量分析的方法之一
Cell culture procedures are conducted with two types of cells:
Primary Cells – Cells isolated directly from human or animal tissue using enzymatic or mechanical methods. Once isolated, they are placed in an artificial environment in plastic or glass containers supported with specialized medium containing essential nutrients and growth factors to support proliferation. Primary cells could be of two types – adherent or suspension. Adherent cells require attachment for growth and are said to be anchorage-dependent cells. The adherent cells are usually derived from tissues of organs. Suspension cells do not require attachment for growth and are said to be anchorage-independent cells. Most suspension cells are isolated from blood system. Some tissue-derived suspension cells are available such as hepatocytes or intestinal cells which are suitable for ADMET applications. Although primary cells usually have a limited lifespan, they offer a huge number of advantages compared to cell lines. When performing primary cell culture, researchers are acquiring an opportunity to study donors and not just cells. Several factors such as age, medical history, race, and sex can be considered when building an experimental model. With a growing trend towards personalized medicine, such donor variability and tissue complexity can only be achieved with use of primary cells and are difficult to replicate with cell lines that are very systematic and uniform in nature and do not capture the true diversity of a living tissue.
Cell Lines – Cells that have been continually passaged over a long period of time and have acquired homogenous genotypic and phenotypic characteristics. Cell lines can be finite or continuous. An immortalized or continuous cell line has acquired the ability to proliferate indefinitely, either through genetic mutations or artificial modifications. A finite cell line has been sub-cultured for 20-80 passages after which they senesce. Cell lines are preferably used for convenience as they are easy to handle and widely published. However, they are less preferred as a biologically relevant option, since they have lost the true characteristics of the original tissue from which they were isolated. Serial passaging is known to cause genotypic and phenotypic variation in cell lines. Variation can often be so far from that of the original tissue to where they do not mimic the in vivo environment very closely. Cells that do not represent the original tissue could result in false negative or false positive findings.
https://bioscience.lonza.com/lonza_bs/US/en/what-are-primary-cells-and-how-do-they-differ-from-cell-lines
Primary Cells – Cells isolated directly from human or animal tissue using enzymatic or mechanical methods. Once isolated, they are placed in an artificial environment in plastic or glass containers supported with specialized medium containing essential nutrients and growth factors to support proliferation. Primary cells could be of two types – adherent or suspension. Adherent cells require attachment for growth and are said to be anchorage-dependent cells. The adherent cells are usually derived from tissues of organs. Suspension cells do not require attachment for growth and are said to be anchorage-independent cells. Most suspension cells are isolated from blood system. Some tissue-derived suspension cells are available such as hepatocytes or intestinal cells which are suitable for ADMET applications. Although primary cells usually have a limited lifespan, they offer a huge number of advantages compared to cell lines. When performing primary cell culture, researchers are acquiring an opportunity to study donors and not just cells. Several factors such as age, medical history, race, and sex can be considered when building an experimental model. With a growing trend towards personalized medicine, such donor variability and tissue complexity can only be achieved with use of primary cells and are difficult to replicate with cell lines that are very systematic and uniform in nature and do not capture the true diversity of a living tissue.
Cell Lines – Cells that have been continually passaged over a long period of time and have acquired homogenous genotypic and phenotypic characteristics. Cell lines can be finite or continuous. An immortalized or continuous cell line has acquired the ability to proliferate indefinitely, either through genetic mutations or artificial modifications. A finite cell line has been sub-cultured for 20-80 passages after which they senesce. Cell lines are preferably used for convenience as they are easy to handle and widely published. However, they are less preferred as a biologically relevant option, since they have lost the true characteristics of the original tissue from which they were isolated. Serial passaging is known to cause genotypic and phenotypic variation in cell lines. Variation can often be so far from that of the original tissue to where they do not mimic the in vivo environment very closely. Cells that do not represent the original tissue could result in false negative or false positive findings.
https://bioscience.lonza.com/lonza_bs/US/en/what-are-primary-cells-and-how-do-they-differ-from-cell-lines
水水的摸鱼日常
“据统计，2020年1月至4月，就有超过6700篇新冠疫情相关论文以预印本的形式率先公开发表在网络平台” tql……
一项发表在PLOS Biology（《科学公共图书馆·生物》）上的最新统计显示，从第一例确诊病例之后的10个月内，科学家迅速响应，全球总共发表了12.5万篇新冠相关论文，其中超过3万篇公布在bioRxiV、medRxiv等预印本网站上。