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全部话题 - 话题: fragment
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h****r
发帖数: 2056
1
来自主题: Programming版 - 请教关于C++内存管理
tcmalloc相gnu libc malloc, 对多线程环境下的memory fragmentation有点帮助,但
是不大。
主流的几个allocator对数组性质的连续内存(比如vector或者其他的固定size的数组
)的管理都有自己的保留,
在free后,并不立即返还给系统,而是留着备用。这个不是memory fragmentation,但
是和memory fragmentation造成同样的问题。
一般vector的resize都是装满一半后开始,如果多个vector的初使size都差不多。
c*******o
发帖数: 8869
2
digestion of PCR product can be very tricky, what i do is following:
1 purify your PCR product with qiagen kit
2 use T4 PNK phosphorylate your PCR product's blunt end
3 ligate your blunt PCR fragment into any vector cutted with blunt end enzyme
(like EcoRV)
4 transformation and mini prep plasmid
5 then use hindIII and EcoRI cut the fragment out of vector
6 purify your hindIII-EcoRI fragment with kit and insert it into the vector
you want to use
this will add one more subcloning step but i am sur
h******n
发帖数: 493
3
来自主题: Biology版 - Re: Yeast Enolase_2 Help

I guess you didn't pick the right protein. :)
My boss did quite a lot of such study before.
For transferrin, a ~75kD glycoprotein, he was able to get
a lot of fragmentation at the C-terminus and got a good
ID using that stretch of sequence.
However, for most other protein, it is really hard to get
enough sequence information for a good protein ID.
ECD, UV laser photodissociation or other high energy
fragmentation methods may producce more fragments.
Low enerygy ways, such as IRMPD, CID and BIRD
z*h
发帖数: 773
4
来自主题: Biology版 - My solution to this.Re: cloning problem
I just did it 1.5 month ago.
Let me explain my ways,
For double disgested vector, using agrose to separate the DNA fragment and
using QIAGEN gel kit to get it.
For mutated DNA fragment, you should design the primer containing restriction
enzyme cutting size plus several NT to ensure the resricting enzymes can work
efficiently. Check this information from Appendiex of NEB catalogue.After
digestion, using DNA concentrator kit to remove enzyme, salt and small end of
DNA fragment.
Mix your vector pl
D*********t
发帖数: 370
5
来自主题: Biology版 - 跪求帮助:为什么克隆不出来
This is very difficult. I don't think I've done 4-fragment ligation (large
fragments!). You may try to
use a shuttle. E.g., put two of them into pKS first. Then ligate another
one. Then you cut out a
(big) single fragment and ligate with your vector. Someone may have
suggested this, I didn't read
all the posts.
H****N
发帖数: 997
6
It should work. Just be aware that you will have two possible recombination
events: in one event, the middle fragment is used and therefore you
insertion will not be introduced; in another, the fragment on the side is
used and you will have the desired allele with you insertion. You have
to have a genotyping strategy that can distinguish these two events. You may
also increase the length of the homologous fragment on the side to maximize
your chance of success. This is actually very similary to
b*******r
发帖数: 179
7
the other thing is
you can try coexpressing the same protein
but use truncations
like you expresses the 20kd fragment
and then expresses the other 20kd fragment as well
and put them together
some times if the two domains are tightly linked
and just have a small flexible linker
some times if u just coexpress them together
they end up touching each other enough
in all honesty
if you doing crystallography
he should just do the two fragments and put them in the xtal tray
as long as you wait for the
w********e
发帖数: 275
8
来自主题: Biology版 - protein mass spec
I'm not familiar with protein mass spec,I'd appreciate some help for a
question.
The protein samples was digested by trypsin, which cuts after K and R. But
why some peptide fragments follow amino acids other than K and R in the
result file? and the same fragment appears more then once. are those
fragments real?
Thanks a lot!
n********k
发帖数: 2818
9
for not very big fragments, what the 2L said works well with 3 fragments or even
more, I never tried more than 4 though. For big fragments, could be harder..
.alternatively, fusion PCR, many of this kind of cloning can be done in a
single fusion-PCR reaction...
S******e
发帖数: 393
10
一个蛋白有没有可能有多个binding sites 与另一个蛋白binding?
我将蛋白A分成4段(no overlap)去做与B的binding,结果显示只有蛋白A的C端那个fragment与B没有binding, 其它3个fragments都与B有binding,这可能吗?
还是我IP有问题? (A的每个fragments都约70kD以上)
顺便再问一下大家做co-IP都用多少总蛋白以及binding多久?
非常感谢!
b******e
发帖数: 88
11
完全可能,非常常见,如果能做定量的话还可以测一下各个fragment之间有没有
competing或者帮助binding的事情
后面那个问题不懂

fragment与B没有binding, 其它3个fragments都与B有binding,这可能吗?
H*g
发帖数: 2333
12
Just curious, how do you know each fragment of protein A maintains the same
tertiary structure as in their endogenous uncut state? If not 100% sure
about this, how do you know any binding information you got from IP is true
or biological meaningful? Why not do mutations/substitutions?

fragment与B没有binding, 其它3个fragments都与B有binding,这可能吗?
b******y
发帖数: 627
13
It is common to divide a huge protein into a few fragments based its domain
structure and use these fragments to narrow down its binding site with
another protein. There are no other obvious ways to do it. Of course, by
doing so, you may not find the robust binding if it is provided through
cooperativity among more than one binding surfaces. This scenario is not
uncommon in biology.
My guess is that your protein A is the extracellular portion of a protein.
If so, I am sure there are a lot of wel... 阅读全帖
l**********1
发帖数: 5204
14
来自主题: Biology版 - 蛋白互做检测: Split GFP vs FRET
Y-2-H 用多重标记 做对照和比较
比如以下的 split-luciferase+GST+HA-epitope tagged
三重标记
they found new proteins interaction paper:
//www.ncbi.nlm.nih.gov/pubmed/21530591
Protocol details:
>the wheat germ in vitro translation system for use in the splitlu
ciferase
assay and co-purifications with glutathione S transferase
(GST)- and HA-epitope tagged proteins (Fig. 2A).
>
In the split-luciferase assay, proteins of interest are fused to
N- and C-terminal fragments of luciferase. If the proteins interact,
the N... 阅读全帖
l******o
发帖数: 103
15
I have the following problem. I want to introduce a point mutation to my
plasmid. The plasmid is super big. So I first cut out a fragment(~4kb) with
XbaI and then ligate it to another vector. After introducing mutation with
mutagenesis kit, the sequencing result is as expected.
Next step is to put the XbaI-XbaI fragment containing the mutation back
into the original clone. After ligation and transformation with DH5alpha I
get a number of colonies (~20) but no colonies in the negative control. B... 阅读全帖
z*******6
发帖数: 679
16
这只是我粗浅的感慨而已...
不知道你了解NET吗?简单说一下,就是neutrophil(也有其他细胞被报道)在收到各
种刺激,细菌病毒,ROS什么的,就会经过一些列酶解的过程释放自己的DNA和histone
到体外,然后形成一个很大的trap,这里同时有high concentration的各种杀菌酶,比
如neutrophil elastase,MPO等等,然后可以将细菌真菌trap同时杀死... 在这个过程
中,出了那些酶类,其实histone fragments本身就具有很强的杀菌能力,号称把
histone fragments(不是whole histone)加到简单的saline之类的buffer里面,细菌
就会被杀死...
这些就是让我感叹neutrophil像最前线的战士一样,尽自己最大的努力阻止外界各种
microbe,最后死的时候还会爆发一下小宇宙,发出histone fragments和NET这种厉害
的武器...
PS 昨天那个review看的真的很不淡定,感叹host和microbe互相竞争同时促进进化...
各种细菌也进化出对付NET的方法,比如说有的就可以... 阅读全帖
s****l
发帖数: 10462
17
有人愿意讨论这里面提及的测序技术吗?优缺点,可行性,第一手经验等等
这里面谁现在是赢家很清楚,但是可见的将来和更远的将来谁会赢?
http://cen.acs.org/articles/92/i33/Next-Gen-Sequencing-Numbers-
全文拷贝如下
试试看图能不能贴上
/1407973177171.jpg
/1408028636124.jpg
OVER STORY
Next-Gen Sequencing Is A Numbers Game
As technical and cost barriers fall, instrument firms move their systems
into research and clinical markets
By Ann M. Thayer
Department: Business
Keywords: instrumentation, gene sequencing, diagnostics, genomics, cancer
[+]Enlarge
09233-cover-Openercxd_17647969-690
A... 阅读全帖
m*********D
发帖数: 1727
18
我是snowyday说的老式酶切连接的老疙瘩了。你这个3KB应该是小菜一碟。上面有人提
到的Q5不错。那个GC-melt对付genomic DNA很好,唯一提醒的是primer(match的部分
)长一点,我一般25-28nt. 在加GC-melt的情况下,annealing的温度适当比用普通Taq
低点,3-5度。
genomc DNA可以用Qiagen的blood and tissue kit提取.一般12-well plate,一个well
就够用20-50次PCR了。
我一般把要PCR的fragment在网上扫描一下酶切位点,重点在don't cut和single cut
list。3kb应该很容易找到合适的位点。然后看自己的vector找合适的酶,加到pcr
primer的5’end。一般情况下,我会在酶点外再加4 nt,很多酶是不能切直接裸露在5’
外的位点的。所以,你的primer该是:4nt-酶点-25ntmatching seq. 3kb,很多情况下
可以用两个不同的酶来克隆。Sal I是老鼠和人genome里少见的酶位点,我几乎每次都
能用上。其他的看运气,识别8 ... 阅读全帖
h**********r
发帖数: 671
19
Thermo的网站上说的:
the average error rate of gBlocks Gene Fragments was determined to
be 1 error per 1,329 bp;
the mean sequence error rate of GeneArt Strings DNA Fragments was 5x lower
than gBlocks Gene Fragments, with 1 error per 6,757 bp.
c*********r
发帖数: 1312
20
来自主题: Biology版 - NGS vs mass spectrometry
ptm
这个我觉得很有用。
关于fragmentation我又想起一点,MS的coverage和DNA/RNA测序的coverage很不一样。
后者可以做到比较均一,毕竟fragmentation还是比较随机的。但是蛋白的就高度依赖
于蛋白酶和被切的蛋白序列。所以有些区域不管用什么酶消化,就是得不到合适大小的
fragment,这样的时候就比较无奈了。。。我的一点个人感受,不知道在实际应用里是
不是一个问题?
g*****x
发帖数: 3283
21
来自主题: Biology版 - NGS vs mass spectrometry
这个不是有或无这么简单。比如在一级质谱测到了一个峰是737.1837 m/z,那么它是不
是一个peptide,或者只是一个nobody?这个就得具体看二级质谱里fragmentation之后
的碎片,能不能和amino acid的pattern match上。假如一个十肽中检测到十八九个碎
片离子而且质量和数据库序列计算出的理论质量吻合很好,那么对于这个十肽的score
就比较高;相反如果只检测到一两个fragment或者质量match的误差较大,那么对应的
score就低。
对于质谱de novo蛋白测序,本质上就是鸟枪法 拼图,在样品纯度高的时候work得不错
,但因为氨基酸复杂程度比核酸高太多,所以对复杂体系基本无能为力,所以应用远不
如bottom-up proteomics广泛。


: 这两个系统的打分系统一样吗?可以互换或者类比吗?

: “如果match不好,那么peptide得到的匹配分数就很低。但是你要
是不介意也可
以使用

: 。”

: 理论上,如果仪器没有问题,测出来的信号就应该表示是样本里存在的蛋
白序列
... 阅读全帖
s****h
发帖数: 31
22
来自主题: Chemistry版 - 急问:关于LTQ Velos ETD参数的设定
最近使用LTQVelos+ETD,使用Thermo自己提供的"Nth double play (ETD)"模板建立MS
方法。
Tuning采用AgiotensinI,1pmol/ul,能看见清晰的fragments。问题是,当我使用这个
tuning file做我的sample时,fragments几乎没有(CID的fragments是没问题的)。请
问各位大侠支招。不胜感谢。在线等。
J******d
发帖数: 506
23
来自主题: Quant版 - memory allocation about vector
Maybe he didn't express his question clearly or you misunderstood?
If he actually meant "which way is less likely to get the memory
fragmented?" (or "safer to use if want to avoid fragmentation"), then of
course, (2).
Basically, I am asking if "fragmentation" is the result of the reason.

>10-
z*******n
发帖数: 1034
24
http://gamerboom.com/archives/83506
发布时间:2014-04-24 11:23:24 Tags:Facebook游戏收益,mark pincus,发现游戏渠道
1)据gamasutra报道,Facebook日前宣布其游戏收益在上个季度仍然强劲,但预计未来
发展将出现困难,因为大量Facebook用户已从桌面平台转向移动平台,而Facebook目前
主要游戏支付收益却是来自桌面平台。
Facebook“整体支付及其他费用”收益是Facebook游戏的主要收益来源,在2014年第一
季度(截止3月31日)达到2.37亿美元,同比去年第一季度增长10%,但其中主要增长却
并非来自游戏业务。
facebook-q12014 payments(from gamasutra)
facebook-q12014 payments(from gamasutra)
Facebook首席财务官David Ebersman表示第一季度Facebook游戏支付收益同比上年仅增
长1%,远低去2013年时Facebook报告所显示的8%年增长率,可见Facebook游戏支付收益... 阅读全帖
C********g
发帖数: 9656
25
转基因玉米的神话
http://www.rainbowplan.org/bbs/topic.php?topic=107689
送交者: 六指 于 2010-03-25 12:25:45
转基因现在是网上的热门话题,这其中自然少不了在转基因食品上市前就已试吃过的方
老师的身影。学习完他的科普熊文“转基因玉米更有益健康”后,再做延伸阅读,稍加
搜索就看到一篇2004年的洋文”Bt corn reduces serious birth defects”【http://westernfarmpress.com/news/10-27-04-Bt-corn-birth-defects/ 】。方老师的文章基本观点,数据,内容编排都和这篇雷同,不少句子更是原文照译。这进一步验证了一条世人皆知的谣言“方老师写的东西,也有成段的引文献或者直接是英语文章翻过来的”。方老师打开门辟谣,关上门立马就造谣,此等大无畏的勇气和人格力量实在是让我等折服。
方老师涉嫌抄袭早已不是什么新鲜话题,这里说说转基因。这篇洋文的两位作者实际上
是做”二阶科学传播“,主要介绍了当年在“营养学杂志”发表的一篇综述【http://jn... 阅读全帖
d*****g
发帖数: 1616
26
http://iwr.cass.cn/zjymz/201109/t20110923_8254.htm
摩尼教是3世纪在波斯兴起的一种宗教,因其创始人为摩尼(216-277?)而得名。
中国旧译明教、明尊教、二尊教、末尼教、牟尼教等。该教在拜火教的理论基础上,吸
收了基督教、诺斯替教和佛教等教义思想而形成自己的信仰,其主要思想是世上光明与
黑暗斗争的二元论。摩尼教在波斯曾盛极一时,后来因受波斯王瓦拉姆一世(274=277
)的残酷迫害,教徒流徙四方。其中向东的一支传入河中地区,以后逐渐东传进入中国
,于762/763年再传入回纥。8-9世纪时,在回纥取得了长足的发展,不久便替代了原来
盛行的萨满教,一跃成为回纥的国教。在漠北回纥汗国(744-840)的推动下,摩尼教
在中原地区也得到了较大的发展。除了伊朗、中亚、中国之外,摩尼教还曾流行于叙利
亚、埃及、巴勒斯坦、北非、欧洲、小亚细亚乃至南亚次大陆等许多地方。摩尼教的经
典也曾由叙利亚文先后译成拉丁文、希腊文、亚美尼亚文、中古波斯文、帕提亚文、突
厥文、粟特文、汉文、大夏文、回鹘文、阿拉伯文等十余种文字。
摩尼教由于屡受迫... 阅读全帖
E******u
发帖数: 3920
27
呵呵,谢谢啊。
后来我也去wiki了一把,这哥们儿真命大,受伤了五次,居然活到现在九十多了
Wounded: Fragment in upper right arm 30 May 1941
Wounded: Bullet wound in left forearm 2 September 1941
Wounded: Shot in back 5 February 1943
Wounded: Wounded in back by strafing enemy fighter-bomber 3 June 1944
Wounded: Shell fragment in Mouth 20 December 1944

7
.
command
he
q*******2
发帖数: 431
28
来自主题: History版 - 北欧为什么没有被西欧殖民
Well, for starters, European nations were not colonized. Being part of a
multi-ethic empire is one thing, turning into a colony is a whole different
matter (once nationalistic feeling started to dominate and nation state
started to replace kindgom and empires as the predominant political entities
, empires just wouldn't survive, Europe just, due to geopolitical reality,
geographical proximity and the fact that Europe got enlightened way earlier
than the rest of the world, even the most backward,... 阅读全帖
t**g
发帖数: 784
29
来自主题: History版 - 死海古卷造假
http://www.bbc.com/news/world-us-canada-45948986
Bible Museum says five of its Dead Sea Scrolls are fake
The Museum of the Bible, in Washington DC, sent five of its 16 fragments for
analysis in Germany.
But results showed "characteristics inconsistent with ancient origin", the
museum said.
Costing $500m (£386m), the museum was opened by Evangelical Christian
and billionaire Steve Green in 2017.
The Dead Sea Scrolls are a set of ancient manuscripts of the Hebrew Bible.
The first of the scrol... 阅读全帖
s********n
发帖数: 26222
30
方舟子在此文中说“虫子不吃的, 人能吃吗”是中国人的质疑, 而美国人是不会问这
样的问题的, 这显然是骗人的。见下文和其中引用的文献, 其中不少是美国人的科研

"Comments on the human health impact of Bacillus thuringiensis toxin gene
product in genetically modified crops"
EPA Review Docket Number OPP-00678B
Professor Joe Cummins
Professor Emeritus of Genetics
University of Western Ontario
I have studied the Environment Protection Agency (EPA) document "Bt Plant-
Pesticides Biopesticides Registration Action Document B. HUMAN HEALTH
ASSESSMENT" and comment in the following ... 阅读全帖
i*****g
发帖数: 11893
31
再说一句,去和做市场销售的人聊天
中国做销售很靠人际人脉,关系,权力,此乃公认
或者更简明扼要概括:中国的市场fragmentation,还不是美国社会那种市场。
此‘市场’非彼‘市场’。
中国出口利润微薄,就是因为这些fragmentation,多个生产者(企业,市,省)一起
向海外,自相竞争。然后产品又是同一类的竞争,只能杀价,还没有形成完整丰富的产
业链(产业生态群落)错开直接切喉式(cut throat)的竞争。
r*******3
发帖数: 10886
32
NEW YORK (AP) — All nine people injured during a dramatic confrontation
between police and a gunman outside the Empire State Building were wounded
by gunfire from the two officers, police said Saturday, citing ballistics
evidence.
The veteran patrolmen who opened fire on the suit-clad gunman, Jeffrey
Johnson, had only an instant to react when he whirled around and pointed a .
45-caliber pistol at them as they approached him from behind on a busy
sidewalk.
Officer Craig Matthews shot seven times,... 阅读全帖
p**********6
发帖数: 3408
33
你这幅就是著名的Prince of the_Lilies:
http://en.wikipedia.org/wiki/Prince_of_the_Lilies
The reconstitution of the so-called "Priest-king" from Knossos is one of the
more popular figures of minoan art. It is made with three ancient fragments
of painted plaster (the crown, the torso, the left leg); the other parts
are modern, hypothetic painting. When Arthur Evans uncovered the plaster
fragments in 1901, he wrote that they belonged to different personages and "
the torso may suggest a boxer".[4]
Anatomica... 阅读全帖
y***u
发帖数: 7039
34
英文版】何新:希腊伪史论的关键六点
2014-03-03 07:11:08| 分类: 默认分类 |举报|字号 订阅
He Xin: Six Key Aspects of Greece Pseudohistory
[ws按:说对了,老何真滴很高兴。他出版《希腊伪史考》,其实就是冒天下之大不韪
,成心对中外的真、假洋鬼子下战书,向已经堆积如山的中外希腊伪史叫板和挑战。在
高某之前一直没有得到有点分量的回应,让他感到有点寂寞。所以读到高文后,他连说
谢谢!]
The key point of the question of authenticity of Greek civilization lies in
six aspects as follows. And these are the vital points of the fact that all
the cunning foreign devils and those fake ones all the time averted positive
response elaborately:
I. The vital point... 阅读全帖
c******n
发帖数: 5697
35
来自主题: Military版 - 飞机残骸终于找到了
Vietnamese searchers looking for a missing Malaysian Airline Boeing Co. (BA)
777-200 said they found a suspected window or door fragment as efforts to
learn the plane’s fate extended to scrutiny of security camera images of
two passengers using stolen passports.
Le Van Minh, a Vietnamese coast guard commander, said in a telephone
interview today that the fragment is suspected to be part of a plane’s
emergency door or window, and that rough seas and darkness were preventing
crews from retrieving ... 阅读全帖
w*****8
发帖数: 703
36
Downed Airliner: Fake Audio Tape Shows US-Backed Hit to Frame Russia
West Blaming Putin for MH17 tragedy.
West Blaming Putin for MH17 tragedy.
Within hours of Malaysia Airlines Flight MH17 crashing into a wheat field in
the Donetsk region of eastern Ukraine last Thursday, Western governments
and media have gradually stoked a frenzy of accusations that Moscow had a
hand in the disaster.
by Finian Cunningham
Strategic Culture
In a devastating twist to emerge over the weekend it now seems that the
... 阅读全帖
D***r
发帖数: 7511
37
来自主题: Military版 - 没有突厥人可能也就没有新疆
别扯了,吐火罗根本不是波斯人后裔
他们的语言跟波斯和印度没有太亲密的关系,除了都是印欧
The existence of the Tocharian languages and alphabet was not even suspected
until archaeological exploration of the Tarim basin by Aurel Stein in the
early 20th century brought to light fragments of manuscripts in an unknown
language, dating from the 6th to 8th centuries AD.[4]
It soon became clear that these fragments were actually written in two
distinct but related languages belonging to a hitherto unknown branch of
Indo-European, now known as Toch... 阅读全帖
C*I
发帖数: 4736
38
相比较而言,石正丽的《Bat origin of human coronaviruses/蝙蝠是人类冠状病毒的
来源》是扎扎实实的抓蝙蝠,解剖蝙蝠,分离病毒,对比DNA,RNA后得出得结论。
请lobbock读一读,说一说,走两步!
http://virologyj.biomedcentral.com/articles/10.1186/s12985-015-0422-1
Review
Open Access
Published: 22 December 2015
Bat origin of human coronaviruses
Ben Hu, Xingyi Ge, Lin-Fa Wang & Zhengli Shi
Virology Journal volume 12, Article number: 221 (2015) Cite this article
Abstract
Bats have been recognized as the natural reservoirs of a large variety of
viruses. Special attention has ... 阅读全帖
G*******1
发帖数: 6411
39
来自主题: Military2版 - 雷达和导弹如何啊?
aim120c range 65miles (>105km)
=================================================================
AIM-120A/B AIM-120C-5
Length 3.66 m (12 ft)
Wingspan 53.3 cm (21 in) 44.7 cm (17.6 in)
Finspan 63.5 cm (25 in) 44.7 cm (17.6 in)
Diameter 17.8 cm (7 in)
Weight 157 kg (345 lb)
Speed Mach 4
Range 50-70 km (30-45 miles) > 105 km (65 miles)
Propulsion Hercules/Aerojet solid-fueled rocket
Warhead 23 kg (50 lb) WDU-33/B blast-fragmentation 18 kg (40 lb) WDU-
... 阅读全帖
d**********0
发帖数: 13081
40
http://www.bbc.com/news/world-europe-31978578
19 March 2015 Last updated at 19:13 ET Share this pagePrint
ShareFacebookTwitter
MH17 disaster: Missile fragment 'found at crash site'
Dutch broadcaster RTL says it has new evidence that the Malaysia Airlines
plane shot down over Ukraine last July was hit by a surface-to-air missile.
Forensic analysis of a metal fragment found at the crash site of flight MH17
by a journalist indicated it was from the warhead of a Russian-made Buk.
This would support ... 阅读全帖
S**I
发帖数: 15689
41
☆─────────────────────────────────────☆
coconut001 (coconut001) 于 (Sat Apr 16 20:51:09 2011, 美东) 提到:
我是这周三面试的,周四回来歇了两天,压跟就没有心情来版上询问。我总共面了6个
人,5个
leader(真的各个title都是leader or senior leader,我就纳闷,M家木有engineer
吗?)和一
个PM。 问题比较简单,
实现strcmp,
实现malloc and free,讨论memory leak怎么解决,以及memory fragment问题
pointer问题(这个问的很杂,比如什么指针存的是一个已经out of scope的address之
后会发生
什么之类的,具体记不清楚了)
multi-processor相关问题,比如multi-processor的机器实现lock要怎么做,我好像说
了memory
bus之类的,中断这时候不起作用了。
Open question(这个问题我用数学模型解释,以至于面我的人以为我是Math的。。。
。。。... 阅读全帖
s*****n
发帖数: 5488
42
malloc一个对象的overhead好想是32bytes.这个大家可以放狗。
那么着就太贵了。而且会造成内存碎片。
如果很小。不如做成固定大小的slot. 改external fragment为internal fragment.
另外一个问题是garbage collection.改成page table方式加上bitmap.
应该不用compact。
基本还是OS书上的内容吧。
g********t
发帖数: 212
43
额 那道题目的话,完整是给你int read_buffer(char*buffer, int len),返回值是-1
或者填好的buffer的大小。如果不是-1需要可能再次调用,再取下一段。
我讨论了这些内容:
1. read_line()的返回值怎么传: 在read_line()里面分配好,还是api调用者分配好把
大小传进来? 如果用c++既有的string类,跨函数体的时候复制是怎么做的,内部内存
表示是怎样的?这些实现在这个scenario里面会有哪些缺陷?在这个scenario里会产生
内存fragmentation吗?有没有办法用一个自己管理的内存池减少fragmentation?当然
,难的设计只是提一下,也没有时间写出来。
2. 然后我用了一个read_line()自己的可以复用的固定大小buffer,一个指针指到上次
自己的内部buffer用了多少了,再遇到read_line就找下一个'n',如果用完了就把
buffer刷新。还有一些边界判定,比如上次取下来的buffer没有取满之类的。
3. 最后简化解是,最后写代码就用了unique_ptr, 里面... 阅读全帖
g********t
发帖数: 212
44
额 那道题目的话,完整是给你int read_buffer(char*buffer, int len),返回值是-1
或者填好的buffer的大小。如果不是-1需要可能再次调用,再取下一段。
我讨论了这些内容:
1. read_line()的返回值怎么传: 在read_line()里面分配好,还是api调用者分配好把
大小传进来? 如果用c++既有的string类,跨函数体的时候复制是怎么做的,内部内存
表示是怎样的?这些实现在这个scenario里面会有哪些缺陷?在这个scenario里会产生
内存fragmentation吗?有没有办法用一个自己管理的内存池减少fragmentation?当然
,难的设计只是提一下,也没有时间写出来。
2. 然后我用了一个read_line()自己的可以复用的固定大小buffer,一个指针指到上次
自己的内部buffer用了多少了,再遇到read_line就找下一个'n',如果用完了就把
buffer刷新。还有一些边界判定,比如上次取下来的buffer没有取满之类的。
3. 最后简化解是,最后写代码就用了unique_ptr, 里面... 阅读全帖
c*********5
发帖数: 458
45
来自主题: Medicine版 - 妈妈骨折求教

FINDINGS: 3 views of the right elbow. Dislocation of
the elbow
joint. Several fracture fragments are evident. The donor
sites are not
clearly visible. There is evidence for fracture of at
least to the
olecranon and the radial head.

IMPRESSION:
1. Dislocated elbow joint.
2. Several fracture fragments are identified without
clearly defined
don... 阅读全帖
y***o
发帖数: 416
46
来自主题: Medicine版 - 男科诊断咨询
男科睾丸活体切片分析结果:
Both biopsies fragments show atrophic seminiferous tubules. These display
thickened basement membranes and are occupied by sertoli cells only.
Spermatogonia are not seen. The interstitium is scant and fragmented,
however, leydig cells appear increased in number with few clusters. Clinical
correlation is suggested.
背景:四年前曾有生育史,最近查出无精子。所以做了睾丸活体检测。医生也说不出为
什么会无精子。
请各位医生帮忙看看,会是什么问题。谢谢!
l**x
发帖数: 110
47
下面这个患者希望能得到版上医生专家的指导意见,危险多大,如何治疗,预后如何?
患者44岁,男,6年前因为肝癌做了肝移植 (符合米兰标准),之后无灾无病好几年。
去年2016年初发现轻微贫血,血色素12,因为当时在服小剂量阿司匹林,于是停服,看
看有没好转。托托拉拉到了年底,还是贫血,血色素10.5。医生说做个内镜。于是在胃
内发现一个肿瘤,内镜医生直觉是GIST。随后CT,但CT却没有异常。4月初第二次胃镜
,GIST依然还在,取样活检表明可能肝癌转移或者是非常罕见的HAC。第二次CT 报告大
小46x35mm,说比较第一次32mm变大了。可能第一次看片医生那天喝多了?肿瘤位置在
Fundus,非常接近GOJ。
AFP好久没有查了,因为肝上的情况一直很好,肝移植前AFP 100多,移植后AFP一直小
于2。上一次至少是2,3年前。也是疏忽了。现在AFP 254. 显然胃上这个要么是转移,
要么是HAC。
下周二医生还要安排一次PETCT,周三见外科医生,估计排除转移外就安排切除了。 求
这里的专家教授指点,这个情况如何是好?下面我贴上最近几个报告。
个人感觉肝移植后5,6年转移到胃实在... 阅读全帖
f******s
发帖数: 314
48
来自主题: Returnee版 - 突然发现姚庆伟他导师很变态啊
姚庆伟 教授
天津大学特聘教授 天津市特聘专家
移动电话:15xxxxxxxxxxx
办公室:022-xxxxxxxxx
Email: x*[email protected]; x**[email protected]
教育背景
l 山西医科大学,学士, 1983
l 山西大学,硕士, 1988
l 伊利诺伊大学-芝加哥分校(Chicago), 博士, 1991
l 哥伦比亚大学(New York), 博士后, 1996-1998
工作经历
l 山西医科大学,助教, 1983-1985
l 山西大学,讲师, 1988-1991
l 北伊利诺伊大学 (DeKalb), 助理教授(tenure track), 1998-2003
l 北伊利诺伊大学 (DeKalb), 副教授(tenured), 2003-2010
研究方向
l 有机合成化学,有机合成方法,过渡金属化学及催化
l 自由基化学,有机反应机理,组合化学
... 阅读全帖
c*********o
发帖数: 1734
49
来自主题: Immigration版 - Review opportunity, 制药
我可以把你推荐给editor,感兴趣的话,尽快PM我。
你需要把你的简单背景发给我, 包括名字,email,现在的organization和title。 还
要在这个journal的reviewer database注册一下。
Title: Thermally induced degradation pathways of three different antibody-
based drug development candidates
European Journal of Pharmaceutical Sciences
ABSTRACT:
Protein-based medicinal products are prone to undergo a variety of chemical
and physical degradation pathways. One of the most important exogenous
stress condition to consider during manufacturing, transport and storage
pro... 阅读全帖
r****y
发帖数: 263
50
收入推荐信模板类别http://user.qzone.qq.com/2915799706/blog/1398826316
Angellee推荐信1
U.S. Departmentof Homeland Security
Feb 19, 2013 Citizenship and Immigration
Services
RE: OpinionLetter to SupportI-140 Immigrant Visa Application Applicant:
Angellee, Ph.D.
Fields of Expertise: Chemical Biology, Antibody Engineering, Protein
Therapeutics, Nanobiotechnology, and Cancer Therapy
Dear Sir/Madam:
I am writing this le... 阅读全帖
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