h******1
发帖数: 13 | 1 问个位化学专家一个问题.
meta-Phosphoric acid 是磷酸 (正磷酸, Phosphoric acid, also known as
orthophosphoric acid) 加热, 脱水, 聚合而成 (Upon heating orthophosphoric
acid, condensation of the phosphoric units can be induced by driving off the
water formed from condensation. When an average of one molecule of water
per phosphoric unit has been driven off, the resulting substance is a glassy
solid having an empirical formula of HPO3 and is called meta-phosphoric
acid). 按这个原理, meta-phosphoric acid 溶于水后, 它应该又变回磷酸. 对不对?
我有一个维... 阅读全帖 |
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h******1
发帖数: 13 | 2 问个位化学专家一个问题.
meta-Phosphoric acid 是磷酸 (正磷酸, Phosphoric acid, also known as
orthophosphoric acid) 加热, 脱水, 聚合而成 (Upon heating orthophosphoric
acid, condensation of the phosphoric units can be induced by driving off the
water formed from condensation. When an average of one molecule of water
per phosphoric unit has been driven off, the resulting substance is a glassy
solid having an empirical formula of HPO3 and is called meta-phosphoric
acid). 按这个原理, meta-phosphoric acid 溶于水后, 它应该又变回磷酸. 对不对?
我有一个维... 阅读全帖 |
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h******y
发帖数: 351 | 3 What kind of cells, which fatty acids are you using? Please give more
details.
Here is what I used for hepatocyte.
Preparation of the fatty acid stocks
The free fatty acids are prepared by dissolving each individual free fatty
acid in 100% ethanol. Most are readily dissolved in ethanol, though some
require heating to achieve fully solubility.
A final concentration of 100 mM for each of the fatty acids as follows:
31 ul 1 M Palmitic Acid Solid, 1 g / 3.3 ml EtOH
... 阅读全帖 |
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h******1
发帖数: 13 | 4 问个位化学专家一个问题.
meta-Phosphoric acid 是磷酸 (正磷酸, Phosphoric acid, also known as
orthophosphoric acid) 加热, 脱水, 聚合而成 (Upon heating orthophosphoric
acid, condensation of the phosphoric units can be induced by driving off the
water formed from condensation. When an average of one molecule of water
per phosphoric unit has been driven off, the resulting substance is a glassy
solid having an empirical formula of HPO3 and is called meta-phosphoric
acid). 按这个原理, meta-phosphoric acid 溶于水后, 它应该又变回磷酸. 对不对?
我有一个维... 阅读全帖 |
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h******y
发帖数: 351 | 5 这几种脂肪酸中，Palmitic Acid 和 Stearic Acid常温下是固体，计算摩尔浓度比较
容易。其他几种常温下是液体，但是大体上他们的密度和水的密度很相近，1ml近似1g
。这些脂肪酸都极易溶于乙醇。溶解Palmitic Acid需要略微加热（50C)。
The free fatty acids are toxic unless they are presented bound to purified,
fatty acid free, endotoxin-free serum albumin, which is used at a typical
concentration of 0.1–0.2%.
Take 31ul 1M palmitic acid, 2.8ul 1M Palmitoleic acid etc and bring the
final volume to 1000ul with 100% EtOH, you will get 0.1M FFA. Add 76ul of
the mixture to 1L culture medium and you w... 阅读全帖 |
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f****n
发帖数: 95 | 7 我在为含氟的丙烯酸酯/丙烯酰胺类高分子寻找good solvent,发现trifluoroacetic
acid (TFA)的溶解能力特别强，很好用。可是，高分子（白色粉末）溶解于新鲜的TFA
之后溶液由无色透明慢慢变为淡黄色透明。
是不是因为TFA是强酸有所谓的发烟现象？浓盐酸就是淡黄色，因为含有少量杂质Cl2
。另外， 含卤素或含硝基的化合物容易变颜色,是少量变质导致的吗？
谢谢！
p.s.
查到有这么一句：“olutions of proteins in trifluoroacetic acid prepared in
vacuo
are clear and colourless; on exposure to air, a purple colour develops.”不
解中···
Nature 174, 509 (11 September 1954); doi:10.1038/174509a0
Anhydrous Trifluoroacetic Acid as a Solvent for Proteins
JOSEPH J. KATZ
Chemistry Di... 阅读全帖 |
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a**********g
发帖数: 48 | 8 Application Development Scientist
Location: South Jersey
Salary Range: Competitive
Benefits: Standard
Employment Type: Full Time
Description: Please send your cover letter and resume to: aiconsulting@
hotmail.com for consideration.
Description of Company:
A non-disclosed biology company is an innovative young company in South
Jersey. The company is creating breakthrough scientific insights and
revolutionary technologies that emerge from the convergence of physics,
nanotechnology, ... 阅读全帖 |
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a**********g
发帖数: 48 | 9 Research Scientist
Location: South Jersey
Salary Range: TBD
Benefits: Standard
Employment Type: Full Time
Description: Please send your cover letter and resume to: aiconsulting@
hotmail.com for consideration.
Description of Company:
A non-disclosed biology company is an innovative young company in South
Jersey. The company is creating breakthrough scientific insights and
revolutionary technologies that emerge from the convergence of physics,
nanotechnology, and biology. It works w... 阅读全帖 |
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t**********1
发帖数: 550 | 10 两个都是ACID，才可能是ACID，而且一定可以是ACID。如果有任何一个不是的话才有问
题。
既然可以做ACID是能够证明的，你问我怎么做就没意思了对吧？咱们讨论的就是设计是
否可行。
这个和design以及实现有关么？告诉你了，design用了ACID MQ，design错了没？ |
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j******g
发帖数: 386 | 11 明白了，也就是说我以前概念有误，beer里的folic acid没那么多，不足以抵消
alcohol对folic acid吸收的阻碍作用。不过你这里算法有点问题，把beer算成folic
acid的唯一来源，这样的话要是不喝beer岂不是肯定有folic acid deficiency啦...
.
acid |
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w*******y
发帖数: 60932 | 12 Drew Estate's ACID line is a monster. Not like a Frankenstein-type monster,
but a sales monster - although I guess it's a little of both. Infused with
herbs and botanicals, ACID creates a unique and highly interesting
experience that's premium in every sense. Others have tried to replicate its
flavor, but one after another, they've failed. ACID stands alone. This week
, enjoy a 60% discount on the small-batch ACID Opulence 3 Torpedo (6 x 54)
10-packs are just $39.99.
To create the ACID Opulence |
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t**********1
发帖数: 550 | 13 其实严肃讨论的，我的12306架构又转移到出票机（支付系统）上面来了。
如果要达到我说的性能，其实支付端要实现一个ACID的系统。幸好我们的应用简单，不
需要通用ACID数据库，只需要简化成一个ACID message queue就好了。
ACID message queue，输入是有序的message。每个message带一个单调递增的message
ID。甚至增量严格定义为1没有问题。
如果抢票机死掉，这个message queue负责回放某个message ID开始的所有交易。恢复
现场。
其实这个message queue关键技术在于存储。存储设备的IOPS要达到至少1M IOPS。
网上搜搜，就可以看到多少battery backed RAMDisk或者SSD能够达标就好了。
思索的几点误区：
1. 文件系统开销呢？
答：raw memory map file，可以确保每次写一个record（512 byte以内）正好一个IO
。记住一定每个记录都要fsync阿。呵呵。
2. message queue挂了怎么办？
答：多于一个串联，甚至可以跨DC partition。这也是... 阅读全帖 |
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t**********1
发帖数: 550 | 14 已经跟他说了，从MQ开始就ACID，他就应该shut up了。MQ到支付也是ACID。因为支付
是ACID他不敢否认吧？
ACID一路到底，还纠结个啥？出结果是必须的。
LOL |
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d****i
发帖数: 2346 | 15 非常感谢！
我们用的是palmitic Acid和Stearic Acid两种，分别去treatmacrophage。据说是先用
乙醇溶解，然后再加入BSA，但是我不太明白你这个protocol。
1. 前面那个31uL、2.8uL。。。是什么的体积？
2. 2.8 ul 1 M Palmitoleic Acid Liquid, 1 ml(1g)+2.93ml EtOH
这里面 1 M Palmitoleic Acid是配好后的浓度？ 1 ml(1g)+2.93ml EtOH里面的1 ml(
1g)的1mL和1g分别是啥意思？
再次感谢！
follows: |
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x*****n
发帖数: 885 | 16 Hi, I am trying to repeat an experiment from a published paper, but I got
confused about one thing.
The process need a PH 3 solution with 8 M urea. The author adjusted the pH
by 0.1% acetic acid.
However, the PKa of acetic acid is 4.75. Should not the buffer always be
arround 4.75 no matter how much acetic acid I am adding?
In another word, what decides the final pH, the PKa or the concentration of
the acid?
Thanks!
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l*********0
发帖数: 85 | 17 Recommended folic acid daily doses: 0.2 mg for children and 0.4 mg for
adults.
A 200-ml glass of beer contains 0.06 mg of folic acid.
Without any extra folic acid supplement, for daily basic requirement, you
need drink 200*(0.4/0.06)=1280 ml beer (355ml/12oz, 1280/355 almost 4
bottles), regardless the negative effect of alcohol in beer.
Less than 1280 ml beer daily, you may gradually suffer from folic acid
deficiency.
But higher than 1280 ml beer daily, alcohol may be the major problem later.
Co |
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y*******d
发帖数: 1674 | 18 我平时吃prenental vitamins的同时还吃2颗每片400mcg的那种folic acid。今天才发
现我吃的prenental vitamins里面已经有 800 mcg folic acid。 相当于我一直都吃
1600 mcg我大概查了一下，说对我的身体比如神经系统不利，但是对宝宝呢？？555现
在都４个多月了， 好担心吃多了药对宝宝不好。folic acid 吃多了是不是不好啊。 |
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t**********1
发帖数: 550 | 19 其实是你没搞清楚状况。
别忘了抢票机是单机。抢到票后给MQ发给消息就好了。别忘了MQ是ACID的。因此消息是
ACID的。至于MQ后如何付钱。是标准网购的程序，真不需要我来说。
至于你说支付系统性能，这不是我操心的问题。但是支付是容易scale out的。这个你
要承认。
只要你承认ACID MQ能做就好了。
关键是MQ的消息设计，消息必须要包含足够信息才行。信息不足就死。但是消息我们自
己随便定义。
其实communication as transaction是关键。 |
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t****n
发帖数: 263 | 20 “两个都是ACID，才可能是ACID，而且一定可以是ACID”。我和你没什么好说的了。我
又不是老师，没义务帮你解惑 |
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t****n
发帖数: 263 | 21 “两个都是ACID，才可能是ACID，而且一定可以是ACID”。我和你没什么好说的了。我
又不是老师，没义务帮你解惑 |
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T**********t
发帖数: 1604 | 22 主要是让蛋白变性沉积，跟covalent bond没啥关系。
http://en.wikipedia.org/wiki/Fixation_%28histology%29
Precipitating fixatives - Alcohols
Precipitating (or denaturing) fixatives act by reducing the solubility of
protein molecules and (often) by disrupting the hydrophobic interactions
that give many proteins their tertiary structure. The precipitation and
aggregation of proteins is a very different process from the crosslinking
that occurs with the aldehyde fixatives.
The most common precipitating fixatives are et... 阅读全帖 |
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g*********3
发帖数: 177 | 24 1. Do we know any other signal pathways mediating amino acid response?
发现大部分关于amino acid的研究是关于mTOR的和mTOR相关的。
2. 上次版上有人提到了amino acid receptor是个悬而未决的问题，不知道是哪位牛提
到的。能展开说说吗？自己查了一下，确实研究的不是很多。 |
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h******y
发帖数: 1374 | 25 请问在in vitro里有啥好方法测量肿瘤细胞的fatty acid metabolism和fatty acid
oxidation?
谢谢！ |
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k****o
发帖数: 728 | 26 一个很简单的反应，2-Sulfobenzoic acid cyclic anhydride跟R-OH在triethylamine
(TEA)存在下开环生成苯磺酸。很简单的一步。但问题是Sigma只能买到90%的technical
grade，结果溶到THF（freshly distilled）后，加入TEA（freshly distilled）
后就马上出现很多白色固体，估计就是不纯的东西比如苯磺酸之类跟TEA生成盐。怎么提纯一
下这个commercial的2-Sulfobenzoic acid cyclic anhydride？我不是有机的，
不过实验室基本反应条件还是有的。
或者谁知道哪里能买到高纯度的2-Sulfobenzoic acid cyclic anhydride?
谢谢！ |
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t*****e
发帖数: 3544 | 27 You may not need to remove the inhibitor in acrylic acid. It only has 100-
200 ppm. De-hibit resin contains amine and I don't know if it works on
acrylic acid. It's not fun to run acrylic acid through column any way. |
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j******g
发帖数: 386 | 28 记得beerl里含大量folic acid,不会引起folic acid缺乏吧？UW CK里一道题，喝了一
年beer，有贫血，结果是缺乏folic acid引起的。想不通。 |
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j******g
发帖数: 386 | 29 可是明明记得Step1时候，alcoholism引起的folic acid缺乏，beer是个例外，只喝
beer不会造成folic acid缺乏，因为beer里含有大量folic acid。 |
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on
发帖数: 199 | 30 There is a lot of articles in internet about low stomach acid problems. Some
claims most people suffer too low instead of too much stomach acid. On the
other hand I failed to find a reputable site and it appears to me the
mainstream view is that if one has a reflux issue an acid suppressor would
be prescribed..
Is the above observation correct? Any comments/thoughts? (I'm a a lay person
) |
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A*******s
发帖数: 9638 | 31 I remember GI used to say: No acid, no ulcer. Even with the finding of H.
Pylori, I still think it is valid. That is why antiacid treatment works for
ulcer.
GERD's symptoms are also related to the acid, it does not matter how much.
In addition, the acid secretion is dynamic, the average base line may be
low, but the peak could be high enough to cause symptoms. |
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d*b
发帖数: 21830 | 33 基本跟年代没啥直接联系，早80年代邓矮改革初，上海丰华圆珠笔厂就生产过acid
free的圆珠笔芯，号称档案芯，也有很多发票是acid free的纸。 |
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az
发帖数: 16686 | 34 Foods high in folic acid
Food Folic Acid μg/Serving
Dietary Folate Equivalents*(DFE)
Ready-to-eat breakfast cereal 100 – 400/serving; read labels
Enriched wheat tortilla 98 / one 8” tortilla
Whole wheat tortilla 24 / one 8” tortilla
Enriched white bread 39 / slice
Enriched pasta, cooked 92 / half cup
Whole wheat bread 14 / slice
Whole wheat pasta 23 / half cup
Lentils, cooked 180 / cup
Black-eyed peas, dried, cooked 105 / half cup
Pinto beans or chickpeas, cooked |
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f****t
发帖数: 25 | 35 突然想要小孩了，不知道要吃哪种。看到pregnatal vitamins+DHA里面好像含folic
acid，那还要单独吃folic acid吗？
也不知道吃多长时间就可以怀了，请妈妈们给点经验，谢谢先！ |
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B******U
发帖数: 631 | 36 第一周的check up时，跟医生说头天晚上发现宝宝呼吸声很奇怪，像是人感冒了鼻子不
通的样子，医生说是acid reflux, 然后给宝宝洗了鼻子，有吸出来好多白白的东西。
看着这么多东西从宝宝鼻子里出来，好心疼啊~
后来，宝宝的症状还是有，我和老公想试着给宝宝吸鼻子的，可是笨手笨脚的倒好像是
吹进去了不少。
请问版上的jms有没有办法避免让宝宝产生acid reflux啊？多谢！ |
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e*****a
发帖数: 545 | 37 感觉你这个不象acid reflux，我娃有严重的silent reflux，也就是不吐出来，但是奶
一直上上下下，胃酸就烧到食道，造成heartburn，也就是所谓的acid reflux。因为我
乳腺炎没有母乳了，她全奶粉消化不良，所以这样。症状是拒绝吃奶，经常听到嗓子眼
有反奶的声音，再有就是严重的时候听她嗓子有非常难受的抽抽的声音（这个很难形容
，你将就着想象一下吧）。
看你描述的，像是gas pain。娃经常会蜷缩起来吗？腿蜷到胸前那样？你要是纯母乳，
是不是吃了些产气的东西，听说那样会让宝宝gas。
你可以试试gripe water，纯草药的成分，我们之前用过，效果不错。
reflux,
★ 发自iPhone App: ChineseWeb 8.6 |
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j*******g
发帖数: 119 | 38 Neocell Laboratories Super Collagen Plus C 和Neocell Laboratories Fish
Collagen + Hyaluronic Acid 哪个更好？还有Neocell Laboratories Fish Collagen
+ Hyaluronic Acid胶原蛋白是哪个类型的，谢谢 |
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t**********1
发帖数: 550 | 39 MQ只不过保持ordered message的ACID。
注意两个词，
第一，ordered是有序的，顺序不能错。
第二，ACID
抢票机保持所有票的状态。你说一共多少票？每天能出多少票？
抢到票，reserve票不给别人了，给MQ就行。MQ挂了，抢票机就不服务了。
退票用另一个MQ 做输入总行吧？
记住MQ消息是有序的。
别忘了，抢票机挂了，可以用另外一个standby抢票机补上。
这个standby抢票机说目前内存所有票的状态是这样，我同步到了消息12345670了。
然后他问MQ，把12345670以后的message给我，因为我是异步同步的。MQ给他，更新状
态，转换成production mode。
别问我所有standby都挂了怎么办？核战争怎么办？ |
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t****n
发帖数: 263 | 40 两年前被人踩过两个原子操作放在一起就不是一个原子操作了。好不容易弄明白了，还
“fix”了据说。现在又来两个acid放在一起还说acid。LOL。一点记性都不长 |
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h******y
发帖数: 351 | 41 I think so. Remember to use fatty acid-free BSA (Sigma, A8806) since you are
looking at the effect of exogenous fatty acid. |
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k***i
发帖数: 662 | 42 August 9, 2007
Business
More Propionic Acid For BASF
Firm will expand capacity in Ludwigshafen and Nanjing
Patricia L. Short
BASF is increasing its annual capacity for propionic acid at its sites in Ludwigshafen and Nanjing.
Production in Ludwigshafen will be expanded by 30,000 metric tons per year and by 9,000 metric tons per year in Nanjing. In Nanjing, production is handled by BASF YPC, a joint venture of BASF and Sinopec.
Once the expansion of the two production facilities is completed by mi |
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t*******n
发帖数: 66 | 43 I wanna to copolymerizw acrylamide and acrylic acid. However, there is some
inhibitor in acrylic acid. I know I need to pass some sort of column. Could
you anyone tell me which clolum and where to by them?? Thanks a lot. |
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s**********e
发帖数: 2888 | 44 是不是变成fatty acid ester之后会容易纯化一点？
我现在做的两个fatty acid isomers的混合物，结构差异很小，一个是一个primary
alcohol，一个是secondary alcohol，有没有什么化学反应可以区分的？
因为需要大量的分离，所以虽然HPLC可以实现，但是还是想找到尽量简单的方法。
谢谢 |
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t*******n
发帖数: 66 | 45 I wanna to copolymerizw acrylamide and acrylic acid. However, there is some
inhibitor in acrylic acid. I know I need to pass some sort of column. Could
you anyone tell me which clolum and where to by them?? Thanks a lot. |
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k***l
发帖数: 25 | 46 Acrylic acid [79-10-7] M 72.1, m 1 3o, b 3 0o/3mm, 7 0o/50mm, d 4
20 1.051, pK2 5 4.25. It can be purified by steam distillation, or vacuum
distillation through a column packed with copper gauze to inhibit
polymerisation. (This treatment also removes inhibitors such as methylene
blue that may be present.) Azeotropic distillation of the water with *
benzene converts aqueous acrylic acid to the anhydrous material.[Beilstein 2
H 397, 2 I 186, 2 II 383, 2 III 1215, 2 IV 1455.] |
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on
发帖数: 199 | 48
Thanks. But this doesn't address the question which is: some claims low
stomach acid can lead to Reflux problems and thus PPI, etc to reduce acid
production is NOT the right solution. However, I don't see any reputable
site to make this argument, so wonder if this argument is in the same
category like vaccine/autsim, etc; |
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