Navigation Links
Picking particles faster than one at a time

s, who is also a professor of biochemistry and molecular biology at the University of California at Berkeley, calls "crystallization in silico."

"In theory, you need twice as many particles as the molecular weight of what you want to image," explains Umesh Adiga, a member of Glaeser's laboratory and a staff scientist in the Physical Biosciences Division. Molecular weight roughly corresponds to the number of atoms in the molecule. "So for a molecule with half a million atoms, you need a million particle images -- thousands for each orientation."

These must be chosen from many millions of candidates, and each must show the whole particle and nothing but the particle. A typical micrograph may show fifteen hundred or more particles, but picking them out isn't easy. The microscope's electron beam has to be kept at low power to prevent radiation damage, so the signal-to-noise ratio is low and the particles are barely perceptible shapes in a field of gray.

"It's hard to find good candidates even with an expert eye," says Adiga. "Having to choose hundreds of thousands of particles is a bottleneck in the process of single-particle reconstruction."

Automatic particle-picking methods have been devised to meet this challenge, but until now even the best yield more than 30 percent false positives -- either poor-quality images of particles or something else altogether, like debris or background noise. Therefore "a human still has to go through them and pick out the good ones," Adiga says.

Adiga and his colleagues decided that concentrating too much attention on the particle itself in the early stages of picking -- for example, approximating its shape and creating a template into which real images are forced to fit, a process common to all previous automatic methods -- simply added to the difficulty. "We decided that if there's noise, there's noise, so at first let's not deal with the particle but with the noise," he says. "If the parti
'"/>

Source:DOE/Lawrence Berkeley National Laboratory


Page: 1 2 3 4 5

Related biology news :

1. Picking apart how neurons learn
2. DNA Molecules Used To Assemble Nanoparticles
3. Tiny particles could solve billion-dollar problem
4. Imaging Lymph Nodes with Nanoparticles
5. Probing The Promise And Perils Of Nanoparticles
6. Probing the promise and perils of nanoparticles
7. Nanoparticles offer new hope for detection and treatment
8. Novel gene-silencing nanoparticles shown to inhibit Ewings sarcoma
9. Basis for DNA ejection from single phage particles
10. Using nanoparticles, in vivo gene therapy activates brain stem cells
11. Breakthrough: Scientists create worlds tiniest organic particles
Post Your Comments:
*Name:
*Comment:
*Email:
TAG: Picking particles faster than one time

(Date:5/11/2015)... May 11, 2015  Through a well-rounded UAS delegation representing ... had a strong showing at AUVSI,s Unmanned 2015 conference last ... Ohio,s UAS industry met with over ... all points along the UAS ecosystem. "Our ... Vice President for Aerospace Rich Knoll . "If you ...
(Date:5/10/2015)... GOTHENBURG, Sweden , May 11, 2015 ... touch fingerprint sensors FPC1025 and FPC1155 from the distributor World ... one of FPC,s distributors in Asia . ... the sensors will be used by smartphone manufacturers in ... is included in the communicated revenue guidance of + 1 000 ...
(Date:5/7/2015)... 2015 Fingerprint Cards (FPC) ... FPC1035, FPC,s smallest touch fingerprint sensors to date.  ... for integration on the backside of the phone, ... possibilities to integrate touch fingerprint sensors in the ... possibilities for module manufacturers to customize the look ...
Breaking Biology News(10 mins):Ohio Flies High at Unmanned '15, Sets Stage for Ohio UAS Conference 2Fingerprint Cards Receives Touch Fingerprint Sensor Order of SEK 235 Million 2FPC Introduces its Smallest Touch Fingerprint Sensors to Date 2
... frogs and finches are becoming more common as pets, ... households now includes some of the most exotic creatures ... become a multi-billion dollar enterprise, but expansion of the ... the maladies that afflict these unusual animals. The ...
... team led by two Texas A&M University anthropologists now ... to 2,000 years earlier than the 13,500 years ago ... The teams findings are outlined in a review article ... Modern Humans in the Americas, which synthesizes new data ...
... found in dye-sensitised solar cells. This type of cell imitates ... plants and light-sensitive bacteria. Annemarie Huijser has succeeded in substantially ... is similar to Grtzel cells. Huijser will receive her PhD ... The use of solar cells is increasing very slowly. ...
Cached Biology News:Veterinarians' guide to hedgehogs, chinchillas and chelonians.....oh, my! 2Substantial improvement in essential cheap solar cell process 2
(Date:5/27/2015)... 27, 2015 The Academy of Model Aeronautics ... celebrating National Model Aviation Day. The third annual celebration will ... to celebrate the model aviation hobby nation-wide and to introduce ... its approximately 2,350 chartered clubs to celebrate the hobby and ... their communities. There will also be a local event at ...
(Date:5/27/2015)... 27, 2015 Empowering biomedical researchers ... disease, Cubresa Inc. today announced its MR Compatible ... in-bore PET Scanner uses silicon photomultiplier detector technology, ... MRI machines from manufacturers like Bruker and Agilent,” ... Winnipeg, Canada. “This enables simultaneous PET and MRI ...
(Date:5/27/2015)... drug discovery and development company, Novogen Limited (ASX: NRT; NASDAQ: ... the Brain Tumor Biotech Summit 2015, being held in ... venue is the Lennox Hill Hospital, East 76 th ... Brain Tumor Biotech Summit brings together the nation,s top cancer ... to promote innovative new therapies for brain tumors.  ...
(Date:5/26/2015)... 26, 2015 Regenestem Network ... cells clinic in Buenos Aires, Argentina. The clinic will ... care specialist. Pastrana has assembled a multidisciplinary team of ... in her state-of-the-art Puerto Madero office. , The ... to phase IV clinical studies in cellular therapies, and ...
Breaking Biology Technology:Academy of Model Aeronautics Foundation to host National Model Aviation Day Motorcycle Rally and Family Fest in Muncie, IN 2Academy of Model Aeronautics Foundation to host National Model Aviation Day Motorcycle Rally and Family Fest in Muncie, IN 3Cubresa Launches Simultaneous PET/MRI Technology 2Novogen to Present at Brain Tumor Biotech Summit 2015 2Novogen to Present at Brain Tumor Biotech Summit 2015 3Novogen to Present at Brain Tumor Biotech Summit 2015 4Novogen to Present at Brain Tumor Biotech Summit 2015 5Regenestem Network and Silvina Pastrana, M.D. Announce the Opening of a New Stem Cell Clinic in Buenos Aires 2Regenestem Network and Silvina Pastrana, M.D. Announce the Opening of a New Stem Cell Clinic in Buenos Aires 3
... 28 Nycomed has granted,Sepracor, Inc. (NASDAQ: ... and,commercialisation rights for Ciclesonide in the United ... novel principle of action. It,is the active ... the,treatment of asthma and in the Omnaris(TM) ...
... China, Jan. 28 /Xinhua-PRNewswire-FirstCall/ -- 3SBio Inc.,(Nasdaq: ... China-based,biotechnology company focused on researching, developing, manufacturing and,marketing ... to the position of Chief Financial Officer effective ... who is resigning for personal,reasons. To assist with ...
... NOVATO, Calif., Jan. 28 BioMarin,Pharmaceutical Inc. (Nasdaq ... Gordon Vehar as Vice President of Research. Former ... Dr. Vehar is the,inventor of numerous biotechnology patents ... awards including two Distinguished,Inventor of the Year Awards ...
Cached Biology Technology:Nycomed's Ciclesonide to be Commercialised in the United States by Sepracor 2Nycomed's Ciclesonide to be Commercialised in the United States by Sepracor 3Nycomed's Ciclesonide to be Commercialised in the United States by Sepracor 4Nycomed's Ciclesonide to be Commercialised in the United States by Sepracor 5Nycomed's Ciclesonide to be Commercialised in the United States by Sepracor 63SBio Inc. Announces Appointment of Kevin Sow Peng Teo as Chief Financial Officer 23SBio Inc. Announces Appointment of Kevin Sow Peng Teo as Chief Financial Officer 3BioMarin Appoints Dr. Gordon Vehar, Vice President of Research 2BioMarin Appoints Dr. Gordon Vehar, Vice President of Research 3
MiniCycler thermal cycler with Hot Bonnet heated lid, holds 25x0.2ml tubes...
For demonstration of Helicobacter pylori...
... with SR-101 Labeled Substrates (red fluorescence; ... measure serine protease activation • No ... FLISP Kits utilize cell-permeable, fluorescently labeled ... measure chymotrypsin-like activity in whole living ...
... the mitochondrial transmembrane potential is ... events that occur following induction ... Detection Kit utilizes a lipophilic ... a mitochondrial activity marker. MitoLight ...
Biology Products: