Investigation of the desorption process in UV matrix-assisted laser desorption/ionization with a liquid 3-nitrobenzyl alcohol matrix by photoacoustic analysis, fast-flash imaging, and UV-laser postionization
Rohlfing A.,University of Munster |
Rohlfing A.,Sequenom |
Leisner A.,University of Munster |
Leisner A.,Soft Solutions |
And 2 more authors.
Journal of Physical Chemistry C | Year: 2010
Ultraviolet matrix-assisted laser desorption/ionization mass spectrometry (UV-MALDI-MS) is a widely used method for the analysis of a variety of biomolecules. The technique relies on the codesorption of matrix and intact analyte molecules from the condensed to the gaseous phase and subsequent analyte ionization. In spite of numerous studies, the MALDI processes are not yet fully understood. Here, we used 3-nitrobenzyl alcohol as a liquid matrix and employed three complementary analytical techniques to monitor the phase transition and development of the ejected material plume. Each of these methods provided a time resolution in the nanosecond range. (i) Photoacoustic stress waves, generated by the recoil momentum of the ejected material, were recorded simultaneously with the corresponding MALDI-generated analyte ion signals. (ii) The MALDI plume expansion was monitored by using a second illumination laser for imaging the plume in dark-field and in scattered-light geometries, allowing discrimination between ejected droplets and gaseous plume domains. (iii) Time-and space-resolved UV-laser postionization of desorbed matrix molecules complemented these studies. The photoacoustic data indicate the transition from a primarily molecular ejection according to a quasithermal model at low laser fluences to a (layer-by-layer) phase explosion above a fluence threshold of about 170 J/m 2. Notably, this threshold coincides well with the onset of sizable ion generation. A few distinct droplets are detected over the whole of the investigated fluence range. © 2010 American Chemical Society.
Li X.,German Electron Synchrotron |
Li X.,Soft Solutions |
Kumar Y.,German Electron Synchrotron |
Kumar Y.,German Center for Neurodegenerative Diseases |
And 8 more authors.
EMBO Journal | Year: 2011
Missorting of Tau from axons to the somatodendritic compartment of neurons is a hallmark of Alzheimer's disease, but the mechanisms underlying normal sorting and pathological failure are poorly understood. Here, we used several Tau constructs labelled with photoconvertible Dendra2 to analyse its mobility in polarized neurons. This revealed a novel mechanism of sorting-a retrograde barrier in the axon initial segment (AIS) operating as cellular rectifier. It allows anterograde flow of axonal Tau but prevents retrograde flow back into soma and dendrites. The barrier requires binding of Tau to microtubules but does not require F-actin and thus is distinct from the sorting of membrane-associated proteins at the AIS. The barrier breaks down when Tau is phosphorylated in its repeat domain and detached from microtubules, for example, by the kinase MARK/Par1. These observations link the pathological hallmarks of Tau missorting and hyperphosphorylation in neurodegenerative diseases. © 2011 European Molecular Biology Organization.
Soft Solutions | Date: 2013-07-16
A method and system for providing a marketplace that enables enterprise collaboration. The method includes allowing an agent to receive a request for purchasing a product and place an order to provide the products to a customer. Further, the method includes allowing the agent to receive the requested products from a vendor and charge the customer for the products with a price as received from the vendor.
Soft Solutions | Date: 2016-01-22
A method for creating an overall image of an object from a plurality of recorded images that each depict a small area of the object, the method including: dividing the overall image into fields; assigning a part of the plurality of recorded images to each of the fields; and composing the plurality of recorded images into the overall image.
Soft Solutions | Date: 2016-03-24
A device, a method and a system for optically determining particle properties, in particular size and reflectivity. The device includes at least one light source assembly having at least one light source, a polarizer assembly, at least one sample holderwhich can be illuminated by the least one light source assemblyfor accommodating particle preparations to be investigated, at least one analyzer assembly, and at least one imaging device with at least one color-resolving matrix image sensor. The device is designed to guide light reflected by a particle preparation and having a color-coded polarization to the at least one matrix image sensor.
Soft Solutions | Date: 2012-07-17
News Article | August 17, 2009
What it means for you Here are some of the reasons you should join VB Profiles Get daily memos and ebooks to know everything that's shaking your industry. Find the newest companies, best candidates and successful investors in your market. Build your own ecosystem with just the companies you care about.
News Article | September 21, 2009
Microsoft is suing five online entities and the individuals behind them for spreading “malvertising,” or online advertising that delivers malware Microsoft announced on 18 Sept that it has filed lawsuits against five entities that it claims have been spreading “malvertising,” or online advertising used to port malware onto end users’ machines. Microsoft is asking the court to shut down those entities, saying that they used Microsoft’s AdManager service, which lets Website owners manage their own advertising inventory, to launch their attacks. The lawsuits are just the latest leveled by Microsoft against spreaders of malicious code. Earlier in the summer, Microsoft’s Internet Safety Enforcement Team filed a civil lawsuit in the U.S. District Court for Western Washington against what they described as a massive click-fraud scheme. In that case, the accused individuals had developed click-fraud attacks against online advertisements for auto insurance and World of Warcraft. In 2009, Microsoft also targeted legal action against a party, Funmobile, which it accused of “spimming,” or spreading links to possibly malicious software through instant messaging. Hong Kong-based Funmobile had apparently been sending instant messages to thousands of Windows Live Messenger users since March 2009. The 18 Sept filings represent yet another front in the battle. “Our filings in King County Superior Court in Seattle outline how we believe the defendants operated,” Tim Cranton, Microsoft’s associate general counsel, wrote in an official Microsoft blog posting on Sept. 1. “In general, malvertising works by camouflaging malicious code as harmless online advertisements. These ads then lead to harmful or deceptive content.” Microsoft’s court filings aim at entities using the business names “Soft Solutions,” “Direct Ad,” “qiweroqw.com,” “ITmeter INC” and “ote2008.info,” which Redmond says used malvertising to spread malware and scareware. “Although we don’t yet know the names of the specific individuals behind these acts,” Cranton continued in the blog posting, “we are filing these cases to help uncover the people responsible and prevent them from continuing their exploits.” The issue of malvertising became a high-profile one on the weekend of Sept. 12, when visitors to the NYTimes.com Website received pop-up messages warning of a virus and ordering them to install fake anti-virus software. The administrators of the site quickly Twittered a public warning: “Attn: NYTimes.com Readers: Do not click pop-up box warning about a virus—it’s an unauthorized ad we are working to eliminate.” Rouge anti-virus software has plagued the Web for years, persuading users to pay for software that either offers no antivirus protection or in fact steals data from their systems. In the April edition of Microsoft’s Security Intelligence Report, officials suggested that, of the top 25 malware or unwanted software “families,” seven had some connection to rogue security software. In 2008, Microsoft released eight security bulletins for 155 vulnerabilities, a 17 percent increase over 2007. Cranton offered some tips in his blog posting for end users looking to avoid malvertising. Much of this will seem standard issue to those regularly online:
News Article | September 19, 2009
Microsoft Corp on Thursday filed five civil lawsuits in Seattle, Washington against alleged “malvertisers.” Malvertising is the term used to describe harmful online advertising and works by camouflaging malicious code as harmless online advertisements, Microsoft's associate general counsel Tim Cranton wrote in a blog. “The lawsuits allege that individuals using the business names “Soft Solutions,” “Direct Ad,” “qiweroqw.com,” “ITmeter Inc” and “ote2008.info” used malvertisements to distribute malicious software or present deceptive websites that peddled scareware to unsuspecting Internet users,” he said. Cranton added that names of specific individuals behind these activities were not known and the lawsuits were being filed to help uncover the people responsible.