z****u
发帖数: 1007 | 1 关于是否sample 混杂. 我的理解是，因为我在寻找一个在这个population里高表达的
gene, 希望在不同的老鼠里都同样的高表达，所以把很多sample pool together应该有
好处。500个cell/mouse实在太少了 。
我们的core说mRNA量在20ng以上，按照mRNA占总RNA 5%左右的比例计算，预测需要1ug
的总RNA.
对single cell sequencing或者RNA amplification 实在有些没信心，能推荐个啥公司
做这玩意的吗。我们的core 反正做不了。 |
|
i******1
发帖数: 21 | 2 1. RNA level check: 1) to make sure the real-time rt-PCR resulst are
specific, using >=2 unique sequences of your target transcript in the
presence of proper controls than unambiguously tell quantification accuracy
and amplification specificity. 2) see how many isoforms in your cell line;
are they in similar lengths; do they share the sequence that can be targeted
by your all your siRNAs? is it possible that the one that cannot be knocked
down have predominant abundance and it it functionally ne... 阅读全帖 |
|
s********8
发帖数: 619 | 3 有人有经验吗?
手上的课题需要从极少量的FACSed细胞中提取RNA做RNAseq.现在一次sorting只能拿到
差不多3000个细胞,运气好的话应该一次可以拿到6000个细胞.
本来打算直接sort到Trizol里面冻起来,这样多sort几次,攒在一起提RNA.可是FACS
facility又不让我用Trizol,所以现在是sort到 RNaqueous micro kit 的lysis buffer
里.提完了RNA一测,几乎啥也测不出来,因为大概也只有十几个ng的样子.
所以我是不是应该考虑用commercial kit来做个amplification?求大牛推荐kit或者好
的方法! |
|
s********8
发帖数: 619 | 4 谢谢楼上各位的回复！我们的sequencing facility好像没有amplification的经验，他
们说要200ng RNA。我再去问问吧。
我也不太想扩增，尽量多做几次FACS，冻起来一起提吧。 |
|
s********6
发帖数: 89 | 5 http://www.amc.edu/PR/PressRelease/04_20_15_drs.html
http://www
Albany Med Announces 2015 Recipients of Albany Prize in Medicine
Albany, N.Y., April 20, 2015—A pair of scientist/inventors who developed
widely used modern research technologies that promise to accelerate medical
discoveries have been announced as the recipients of the Albany Medical
Center Prize in Biomedicine and Biomedical Research for 2015. They are:
Karl Deisseroth, M.D., Ph.D., D.H. Chen Professor, Professor of
Bioengineering... 阅读全帖 |
|
e****l
发帖数: 115 | 6 http://jmd.amjpathol.org/article/S1525-1578(15)00046-X/abstract
Journal of Molecular Diagnostics
May 2015 Volume 17, Issue 3, Pages 273–283
Accurate Classification of Germinal Center B-Cell–Like/Activated B-Cell–
Like Diffuse Large B-Cell Lymphoma Using a Simple and Rapid Reverse
Transcriptase–Multiplex Ligation-Dependent Probe Amplification Assay
A CALYM Study
Please send to [email protected]
/* */
Thanks so much!! |
|
l********n
发帖数: 260 | 7 Molecular Diagnosis & Therapy
October 2014, Volume 18, Issue 5, pp 579-585
Date: 12 Jul 2014
Development and Validation of a Tetra-Primer Amplification Refractory
Mutation System-Polymerase Chain Reaction Combined with Melting Analysis-
Assay for Clinical JAK2 V617F Mutation Detection
Weiwei Liu, Tingting Hu, Yuming Chen, Xinju Zhang, Xiaoye Gu, Ming Guan |
|
l***7
发帖数: 50 | 8 Nature Protocols 3, 1452 - 1456 (2008)
Touchdown PCR for increased specificity and sensitivity in PCR amplification
Please send to [email protected]
/* */
Thank you very much! |
|
Q**********r
发帖数: 214 | 9 谁能帮忙下载这篇文章
Nat Methods. 2006 Jul;3(7):545-50.
Amplification of complex gene libraries by emulsion PCR.
email:[email protected]
/* */
多谢了！ |
|
Q**********r
发帖数: 214 | 10 Nat Methods. 2007 Mar;4(3):257-62. Epub 2007 Feb 18.
Rapid SNP diagnostics using asymmetric isothermal amplification and a new
mismatch-suppression technology.
这几天在本版求了三篇文章了，真感谢大家在谢张争论的百忙中帮忙！ |
|
i***l
发帖数: 1656 | 11 sensitivity are the same-----both with resolution of single base
specificity is N/A--------one targeted, the other non-targeted.
it's not "比sanger快", say, it is with much higher capacity (amplification
capacity per reaction) 比sanger
惑, |
|
x*****e
发帖数: 309 | 12 "后者是一对一的关系，又没有放大信号"?? 得看你的蛋白被标记了多少个biotin吧. |
|
F****8
发帖数: 289 | 13 Google讨论中，一位叫Mike的回应。
https://groups.google.com/forum/#!topic/crispr/V1FALNbspCo
This looks sketchy.
In the discussion following this tweet @GaetanBurgio claims that this is a
PCR result (not a T7E1 assay). The significantly smaller bands in sample
lanes(1-7) was deletion bands caused by NgAgo. And yet on his control lane (
Lane 8 according to him) there's also smaller bands.
He didn't do T7E1 assay because (from what I gathered in the tweets and
sorry if I got it wrong) the effects of NgAgo is ... 阅读全帖 |
|
l*****7
发帖数: 8463 | 14 1
http://disinfo.com/2011/05/could-human-photosynthesis-power-the-future/
Could Human Photosynthesis Power The Future?
Posted By: phunkychic666 MAY 4, 2011
Chlorophyll. Photo: Wilfredo R. Rodriguez H. (CC)
Chlorophyll. Photo: Wilfredo R. Rodriguez H. (CC)
By Hank Mills for Pure Energy System News:
Dr. Arturo Solis Herrera has developed a technology that utilizes the
properties of melanin – the animal analogue to chlorophyll. His melanin
based (polihydroxyindol) photo-cell absorbs a broad spectru... 阅读全帖 |
|
c********n
发帖数: 225 | 15 【记录历史】NgAgo实验流程Addgene更新前后的比对
读好书，读好文，有益身心健康。
看文章，做记录，做总结，找原因，找规律，可以避免浪费以后的时间和精力
我们来记录一下韩春雨实验室提供的NgAgo实验流程，
在Addgene 2016年8月8日 更新前后，做一下比对
Reference：
原始发表的protocol
doi:10.1038/nbt.3547-s1, supplementary information
更新后的protocol
Addgene Han Lab added tips 2016年8月8日
https://www.addgene.org/78253/
under “RESOURCE INFORMATION” section “Supplemental Documents”
先看title
更新前
A general protocol of NgAgo/gDNA-mediated genome editing and examination (
T7E1 assay)
更新后
A general protocol of NgAgo/gDNA-mediate... 阅读全帖 |
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c********n
发帖数: 225 | 16 【生物界的“坏小子们”】（二）PCR
三十几年以前，1983年，Kary Mullis 发明了Polymerase Chain Reaction
（PCR）。
这是一个disruptive technology。
生物研究领域被拓宽了，也影响到了人们生活的各个方面。
n年以前，大学秋季刚开学的时候，有这么一个讲座。
幻灯片投影的大屏幕上是一张意大利某教堂的地砖图案。
“See，the Double Helix has always been there！”
演讲者不停的前后左右摇摆着，一只脚还在 “一二三”，“一二三二一” 不断
变换的踩着节拍。他穿着一套有点别扭的深蓝色西装，里面是件浅蓝色衬衣，
没有打领带，领子就这么随意的竖起来。他的眼睛里时不时发射出一点“闪
闪”的光，随意的扫一扫满满的几百人的阶梯教室。
不管以前有没有读过有关他背景的信息，看到这么一个人，站在这么一个正式
的Scientific Seminar的讲台上，都会震惊一下 - 这真就是Kary
Mullis，inventor of PCR， 诺奖获得者？
接下去，Kary Mullis 谈到了他如何在高速公路128上... 阅读全帖 |
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m****j
发帖数: 120 | 17 请好心人帮忙下载这边文章的全文：
Controlled stem cell amplification by HOXB4 depends on its unique proline-
rich region near the N terminus.
Blood. 2017 Jan 19;129(3):319-323. doi: 10.1182/blood-2016-04-706978. Epub
2016 Nov 8.
多谢！ |
|
s****t
发帖数: 461 | 18 Liu W, Dong D, Yang Z, Zou D, Chen Z, Yuan J, Huang L (2015) Polymerase
spiral reaction (PSR): A novel isothermal nucleic acid amplification method.
Sci Rep 5:12723–12730.
大家来敬仰一下nucleic acid parallel synthsis的新发现。
这个尽然也能发表？审稿的都是文科生吗？ |
|
发帖数: 1 | 19 我这个半吊子biologist来说一句：
DNA/RNA和protein
NGS/MS
最大的区别，还是：
核酸可以很容易的amplification
而蛋白质不可以？
gene
MS |
|
A******y
发帖数: 2041 | 20 So how much RNA or cDNA sample do you add to your qPCR? What you do is take
a sample (usually control), do a x2 serial dilution and see if your cycle
is close to a single cycle per dilution and if it is linear. It is call PCR
amplification efficiency. It doesn't have to 100% but I think you should
have >90% and linear. |
|
m*****1
发帖数: 5879 | 21 年底毕业，求职中，请有工作机会的推荐，谢谢。
经验：
Instrument operation and maintenance: Varian GC-MS, Shimadzu GC, Beckman
HPLC, Agilent HPLC,
Thermo LTQ, Thermo TSQ vantage. Thermo nLC-NSI-LC/MS/MS,
Separation: Nano and μ-LC, HPLC, PAGE, Agrose gel
Detection: mass spectrometry, UV spectroscopy.
Biological technique: Cell Culture, RT-PCR, siRNA-knockdown, Plasmid
Amplification and
Transformation, RNA and DNA extraction from cells and tissue, SDS-PAGE
paper 有一篇10分的一作，若干5分左右的非一作。
希望找公司的工作，暂时不考虑博后位置，谢谢。请站内。 |
|
m*****1
发帖数: 5879 | 22 经验：
Instrument operation and maintenance: Varian GC-MS, Shimadzu GC, Beckman
HPLC, Agilent HPLC,
Thermo LTQ, Thermo TSQ vantage. Thermo nLC-NSI-LC/MS/MS,
Separation: Nano and μ-LC, HPLC, PAGE, Agrose gel
Detection: mass spectrometry, UV spectroscopy.
Biological technique: Cell Culture, RT-PCR, siRNA-knockdown, Plasmid
Amplification and
Transformation, RNA and DNA extraction from cells and tissue, SDS-PAGE
paper 有一篇JACS的一作，一篇10几分的二作，若干5分左右的非一作。
求工作。站内或者回帖留下联系方式。 谢谢。 |
|
e**d
发帖数: 42 | 23 哪位大侠能帮忙找到这篇中国专利？先拜谢了。
Patent Information
Sep 16, 2015
CN 104910001
A
Faming Zhuanli Shenqing
7pp.
Patent
2015
CODEN:CNXXEV
Method for synthesizing 5-chloro-1-indanone
By: Xu, Wei; Wang, Yi; Zhan, Changjuan; Wang, Hua; Yang, Xiao
Assignee: Peop. Rep. China
Abstract:
The invention discloses a method for synthesizing 5-chloro-1-indanone, and
belongs to the field of org. synthesis. The method comprises the steps of:
carrying out a reaction between 3-chlorobenzaldehyde as raw material and
malonic a... 阅读全帖 |
|
y****a
发帖数: 172 | 24 这个也太粗糙了。1979年的东西还拿出来用？
感觉就是回归出来的。
首先，震源深度就没考虑。
最重要的还是场地条件。岩石，硬土，软土，差别很大。现在这种估算至少要做一个
one dimensional amplification. |
|
a*******r
发帖数: 344 | 25 My guess is as long as the frequecy of your expected exitation force (for
example truck running over a series of speed bumps) is far away from the
pipe's resonant frequency (and it is very likely so), your pipes are going to
be fine in terms of dynamic forces.
Worst case of scenario, your truck hit on speed bump at high speed, the
force transfered from timber block to pipe will be a pulse excitation. If
this is true, a dynamic amplification factor of 2 should be ok.
Buckling of pipe wall under i... 阅读全帖 |
|
a*******r
发帖数: 344 | 26 My guess is as long as the frequecy of your expected exitation force (for
example truck running over a series of speed bumps) is far away from the
pipe's resonant frequency (and it is very likely so), your pipes are going to
be fine in terms of dynamic forces.
Worst case of scenario, your truck hit on speed bump at high speed, the
force transfered from timber block to pipe will be a pulse excitation. If
this is true, a dynamic amplification factor of 2 should be ok.
Buckling of pipe wall under i... 阅读全帖 |
|
h**e
发帖数: 410 | 27 Thanks for your comments, very helpful.
One more question to bother, Per AASHTO code, vehicle dynamic amplification
factor IM = 1.33, which code you cited here to get factor as of 2?
to
fo running an "analysis". |
|
f**c
发帖数: 629 | 28 check out AREMA manual or Hays railraod engineering book
For railraod track analysis, there is a equation for computing dynamic
impact factor, which is a function of the train speed. I remember it can go
up to 2.
amplification |
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a*******r
发帖数: 344 | 29 2 is the upper bound of dynamic response to static response of a step
function.
I just want to be conservative.
amplification |
|
d*b
发帖数: 130 | 30 Epicom New Hires Job Descriptions:
1. RF EE Design Engineer:
(1) RF Front End MMIC design experience: Handset Power Amplifier, WiFi/WiMax
Power Amplifer, Low Noise Amplifier, Switch, filter design, Frequency ~
1GHz-10GHz
(2) PCB design experience: PCB design to test PA, LNA, Switch, filter, etc.
(3) Familiar with MMIC design tools, such as Agilent ADS, AWR MWO or AO,
HFSS, SONET, AutoCad, Cadence, etc.
(4) Familiar with Device (HBT, PHEMT, Diode, etc.) and Device Modeling tool,
such as Agilent I |
|
f*****0
发帖数: 489 | 31 most (voltage feedback) opamps follow the Linn 3-stage topology: a
differential pair upfront for better DC control, a high gain (typically
single-ended) voltage amplification stage (VAS) and a 0db buffer / current
amplifier. the VAS typically have very high output impedance (typically into
the mega ohm range inside of a chip). so even the slightest load will
severely overload a VAS, causing the gain to drop pecipitiously.
what the buffer does is to isolate the VAS from the load. from that
perspe |
|
s******e
发帖数: 2181 | 32 First of all, thank fku0000 to settle my power amplifier question.
Does there exist ultra frequency amplifer? I mean ranges from 0Hz to higer.
Since I want to receive respiration signals, whose frequency is normally 0.2
-0.5Hz.
I found the lowest frequency for TDAs is 10 Hz unfortunately. |
|
f*****0
发帖数: 489 | 33 what exactly do you want to know? |
|
f*****0
发帖数: 489 | 34
those transistors have ft around 200 - 300mhz. they are at best good for
IF amplification and you will need true RF transistors to amplify OTA
signals.
pretty much all OTA receivers have AGC and you don't really need a
booster unless the receiver really sucks. |
|
ET
发帖数: 10701 | 35 想了半天，终于明白了你这个问题了。
你的意思是说，flicker noise的corner frequncy ，在经过一个single ended amplif
ier (2-pole filter),这个corner frequency 会会被spread out?
这个flicker noise的noise corner是基于noise density.
而经过一个single-ended amplifier后（two-pole), 算出的noise是total noise. 这时
的bandwith是这个filter的bw.
我认为不是一个概念。
but
for
noise |
|
m*****t
发帖数: 3477 | 36 to simplify my question:
If you plot the output noise current power spectre, the corner frquency is
much higher than that of the equivalent input noise voltage power spectre.
why is that?
amplif
这时 |
|
ET
发帖数: 10701 | 37 问个简单问题，
single-ended nmos amplifer, 如果是current 用来biasing,
增加这个current, gain 增加还是减少？（saturation region)
这玩意，output resistance 用1/(lammda*Id)来看是减少的
gm=sqrt(kn(w/L)Id)是增加的，最后的增加还是减少难道不是还要看具体值？ |
|
s*****o
发帖数: 22187 | 38 不得不赞学习精神先，我明天有空也好好学习一下：）
amplif
amplifie |
|
l****o
发帖数: 184 | 39 首先谢谢回答得这么仔细，赞一下学习精神：）
关于transfer function 我是这么推导的，见附图
Gain boosted amplifier在这里的作用就是把gm2提高了(AGE+1)倍
所以在表达式中与普通cascode 不同的地方就是多了一个(AGE(S)+1)
这个+1的部分就create another zero, 但是这个transfer function所表示出来的
Non-dominate poles 分别是the output of the gain boosted amplifier(V2)和node
v1，
这就与另外一个pole需要和zero在一起的假设相矛盾。
我不太明白我这样推倒错在什么地方，我分别看了2002年的一篇tcas 和berkeley的
lecture video,
都有相似的结果。
至于我说把gm3/c3 push到high frequency上面，这个当然要具体问题具体分析，越往
外推越好。
再次感谢帮我解答问题，，：）
amplif
amplifie |
|
l****o
发帖数: 184 | 40 忘记加图片了
。。
amplif
amplifie |
|
l****o
发帖数: 184 | 41 这个计算transfer function的方法确实不错，简化了不少，只是如果把output
resistance全部省略，会不会对最后的gain计算会有影响？
Additional amplifier确实只是boost the output impedance,,整个amplifer得gm 还
是约等于gm1,但是你如果计算一下the impedance @V1， 你会发现V1 is voltage
sampled, and the impedance is
1/(gm2*(AGE+1)),
当然在那么高的frequency，AGE早就消失了。
换个角度来说，GE amplifier的作用就是keep the drain of bottom transistor more
constant.当然相对来说，the impedance at V1 is smaller.
不知道这样的说法对不对
opamp
/ |
|
S****e
发帖数: 1063 | 42
offset呢
I don't know why you keep refering to OTA, and I run out of words to explain
it. however, you can refer to this app note for how a voltage error
amplifer (compensator) works. Vout-Vref=0 does not mean the output Ic(t)=0.
http://www.intersil.com/data/tb/tb417.pdf
If you take a look at the pdf i linked previously, it explains your question
regarding D>0.5 alot better than I can do in a post. |
|
q*******n
发帖数: 52 | 43 谢谢大家的讨论.
不是专门做LDO去卖, 是系统里的一部分.
需要做的是把5V转成3.3V, 用来supply大概6-20mA的一块电路.(一半analog一半
digital runs at 1MHz).
有两个问题在考虑:
1. 要求Cload 0 – 0.1uF 之间都稳定, 不知道普通的miller compensation 是否够
用.
2. load current 快速变化的时候(1MHz), Vregular spike 最好小于200mV.
想先用一个cascode amplifer 加Pmos 和 Resistors 搭一下, 看看结果怎样. |
|
Q*S
发帖数: 395 | 44 你这是在调戏电路板大牛们了。我是学医出身的，搞 bio 的人那点电路知识我还不知
道。
首先这不算电路图，三角也不是运放，这最多算个框图什么的，一个三角算一个功能单
元，
至于它是什么功能完全看心情，不过在这张图上已经把主要功能给标注了，所以可以大概
猜个差不多。
Input voltage 通过 Control amplifer 驱动 counter electrode, 驱动电位等同于
Working Electrode 和 Reference Electrode 之间的电极电压 （这样CE/RE之间电压差
基本是零，Electrometer 单元等比放大 Working Electrode 和 Reference Electrode
之间的电压 （供纪录Working Electrode 电位 ）而Working Electrode 对 Reference
Electrode 之间的电压差通过 Rk 转换成电极电流(供纪录Working Electrode 电流）。
基本上就是一个cyclic voltammetry的电路图。 |
|
|
b*******t
发帖数: 33714 | 46 二手仪器买来或者买前找找spec和manual
你的系统关心的第一件事情是频率范围，第二是最终接到transducer上的电信号需要多
大amplitude，看看amplifier的输出功率能不能支持。所谓50dB flat amplification
是放大小信号用的，在saturate之前可以做到输入信号的线性放大 |
|
p****i
发帖数: 5597 | 47
amplification
多谢獭獭，学习了～～
我的输出的线是50欧的，我从0.1V输入开始试的，结果输出基本为0。。。。后来把50
欧的线拔了，输出有3V。然后输入是1V的时候，输出有67V。但是都是在输出没有接线
的情况下，接线的话最大只能到3V |
|
|
c***u
发帖数: 843 | 49 这个公司 产品线很多啊! 不过貌似欧洲工资比美国低不少？ |
|
m******n
发帖数: 194 | 50 I guess you are talking about Chinese teams,
THE PCR patent must be more than the following two
# the Cohen-Boyer patents on the basic techniques of genetic engineerin
g, which brought in around $195 million for Stanford University and the
University of California prior to its expiration in 1997;
# the Axel Patents on co-amplification of plasmids in eukaryotic cells,
which brought in $395 million to Columbia University prior to its expira
tion in 2001; |
|
