How It Works
Electron Transfer Dissociation
The Scientist Staff | May 1, 2008
Collision-activated dissociation (CAD), the most widely used peptide ion fragmentation technique for peptide sequence analysis by tandem mass spectrometry, works great for small peptides but is problematic for labile posttranslational modifications (PTMs). In the last decade, researchers have developed an alternative, electron capture dissociation (ECD), which involves reacting multiply-p
How It Works: Two-Photon Microscopy
Alla Katsnelson | Nov 1, 2007
Related Articles Going Live Tips for choosing a microscope setup Pooling resources Prioritizing speed Mix and match Deep down view Sticking to the surface Two-photon microscopy offers two advantages over other live cell imaging techniques: It penetrates up to 1 mm into tissue and it minimizes phototoxicity because the beam excites just a single focal point at a time. In order to excite a fluorophore labeling the tissue, two long-wavelength, low-energy photons must meet nearly simultan
How It Works: Patch Clamping
Brendan Maher | Oct 1, 2006
http://www.the-scientist.com/supplementary/flash/24912/1.html Click here to view diagram _blank Credit: ILLUSTRATION: ANDREW MEEHAN" />http://www.the-scientist.com/supplementary/flash/24912/1.html Click here to view diagram _blank Credit: ILLUSTRATION: ANDREW MEEHAN Related Articles A Master Regulator in the Brain Meeting of the Minds Singing in the Bird Brain Patch Clamping Unhooked Ten Steps to Better Patch Clamping Paul Greengard and Per Svenningson discuss DARPP-
HIW - FTICR-MS
Jeffrey M. Perkel | Sep 1, 2006
http://www.the-scientist.com/supplementary/flash/24575/1.html Click to view enlarged diagram _blank Credit: ILLUSTRATION: ANDREW MEEHAN" />http://www.the-scientist.com/supplementary/flash/24575/1.html Click to view enlarged diagram _blank Credit: ILLUSTRATION: ANDREW MEEHAN Sporting greater mass accuracy than other mass spectrometers, Fourier transform-ion cyclotron resonance (FTICR) mass spectrometry instruments have the ability to resolve and sequence intact
Bead-Based Multiplexing
Jeffrey M. Perkel | Aug 1, 2006
http://www.the-scientist.com/article/flash/24106/1/ Click to view enlarged diagram Credit: ILLUSTRATION: ANDREW MEEHAN" />http://www.the-scientist.com/article/flash/24106/1/ Click to view enlarged diagram Credit: ILLUSTRATION: ANDREW MEEHAN There are a number of ways to multiplex, but one of the most common relies on solution-based arrays of microscopic beads measuring several microns in diameter.Like planar microarrays, these arrays are addressable - that is,
Atomic Force Microscopy
Jeffrey M. Perkel | Jul 1, 2006
http://www.the-scientist.com/article/flash/23821/1/ Click to view enlarged diagram Credit: ILLUSTRATION: ANDREW MEEHAN" />http://www.the-scientist.com/article/flash/23821/1/ Click to view enlarged diagram Credit: ILLUSTRATION: ANDREW MEEHAN Invented in 1986 atomic force microscopy (AFM) has become a valuable tool for life scientists, offering the ability to image aqueous biological samples, like membranes, at nanometer resolution. The technique is akin to
TIRF Microscopy
Jeffrey M. Perkel | Jun 1, 2006
/article/flash/23556/1/Click to view enlarged diagram Credit: ILLUSTRATION: ANDREW MEEHAN/ACKNOWLEDGEMENT: MICHAEL DAVIDSON" />/article/flash/23556/1/Click to view enlarged diagram Credit: ILLUSTRATION: ANDREW MEEHAN/ACKNOWLEDGEMENT: MICHAEL DAVIDSONStick a soda straw into a glass of water, and from the side, the straw will appear to bend at the interface between air and water. That effect is caused by the different refractive indexes of the air and water, which causes the li
Miniaturizing HPLC
Jeffrey M. Perkel | May 1, 2006
insert urlClick to view enlarged diagram Credit: ILLUSTRATION: ANDREW MEEHAN" />insert urlClick to view enlarged diagram Credit: ILLUSTRATION: ANDREW MEEHAN The two chips illustrated below represent the next generation of high-performance liquid chromatography (HPLC). Their manufacturers - Agilent Technologies and Nanostream - have miniaturized and simplified the traditionally reagent-intensive process with microfluidics in order to boost sensitivity and thro
Quantitative Molecular Microscopy
Jeffrey M. Perkel | Apr 1, 2006
Credit: COURTESY OF MARISA DOLLED-FILHAST, HISTO Rx" /> Credit: COURTESY OF MARISA DOLLED-FILHAST, HISTO Rx Traditional histopathology analysis has two basic problems. First, it isn't granular enough: Pathologists typically grade overall marker-staining intensity using a four-point scale. The other problem is that these measurements don't account for the sometimes-subtle changes in subcellular localization that can indicate disease. Beta-catenin, for instance, is a biomarker for colon can
The Multimode Microplate Reader
Jeffrey M. Perkel | Mar 1, 2006
Credit: ILLUSTRATION: ANDREW MEEHAN/ACKNOWLEDGMENT: CLAUS LARSEN, BMG LABTECH" /> Credit: ILLUSTRATION: ANDREW MEEHAN/ACKNOWLEDGMENT: CLAUS LARSEN, BMG LABTECH View enlarged diagramThe days of single-mode microplate readers are over; multimode readers have taken over the lab. One such instrument, BMG Labtech's PHERAstar (shown here), can acquire fluorescence intensity, fluorescence polarization, time-resolved fluorescence, luminescence, absorbance, and PerkinElmer AlphaSc
Genotyping Microarrays
Aileen Constans | Feb 1, 2006
For most researchers DNA microarrays are synonymous with high-throughput gene expression analysis. But they also are invaluable genotyping tools. Now that the International HapMap Project (see article, p.68) is complete companies are putting ?these tools into researchers hands, including the HumanHap300 BeadChip from San Diego-based Illumina, whose construction is illustrated here.Unlike other microarray platforms, in which specific oligonucleotide probes are either synthesized
Q-Tof Mass Spectrometer
Aileen Constans | Jan 1, 2006
Invented a half-century ago by Nobel laureate Wolfgang Paul, the quadrupole mass filter has become an integral part of some of the most sophisticated mass spectrometers. Consisting of four parallel metal rods on which a fixed direct-current voltage and alternating radio-frequency voltage are applied, quadrupole mass filters allow users to selectively filter all ions except for those of a specified mass to charge ratio (m/z), depen
How It Works | Lab-on-a-Chip
The Scientist Staff | Aug 28, 2005
With their tiny reaction volumes and parallel architecture, lab-on-a-chip systems promise to lower the cost and raise the quality of life science research.
How It Works | Optical Trap
The Scientist Staff | Aug 28, 2005
Unlike the other technologies highlighted in this issue, optical trapping systems are not typically purchased off-the-shelf.
How It Works | Automated DNA Sequencer
The Scientist Staff | Aug 28, 2005
Sequencers have come a long way since 1986.
How It Works | BLAST
The Scientist Staff | Aug 28, 2005
It's common knowledge that BLAST's Web interface puts the power of the National Center for Biotechnology Information (NCBI) on users' desktops.
How It Works | Microarray Scanner
The Scientist Staff | Aug 28, 2005
Microarrays are nothing without their scanners, the instruments that extract the array's data in computer-readable form.
How It Works | Yeast Two-Hybrid Assay
The Scientist Staff | Aug 28, 2005
The ultimate realization of the yeast two-hybrid (Y2H) assay is the interactome.
How It Works | MALDI-TOF/TOF
The Scientist Staff | Aug 28, 2005
It's been 20 years since Hillenkamp and Karas developed MALDI.
Improving Lab-on-a-Chip
Aileen Constans | Jan 30, 2005
has upped the ante in microfluidics-based gel electrophoresis.