A simple and sensitive spectrophotometric assay for quaternary ammonium compounds (QACs) based on Dragendorff's reagent is described. Although not specific for a particular QAC, the assay allows for rapid survey of tissue for QAC content. A separation method for QACs in halophyte tissue containing high levels of cations was developed using ion exchange resins and ninhydrin to remove the amino a...

The aim in this study was to assess the effectiveness of a quaternary ammonium chloride (QAC) surfactant in reducing surface staphylococcal contamination in a routinely operating medical ward occupied by patients who had tested positive for methicillin-resistant Staphylococcus aureus (MRSA). The QAC being tested is an antibacterial film that is sprayed onto a surface and can remain active for u...

Query auto completion (QAC) models recommend possible queries to web search users when they start typing a query prefix. Most of today’s QAC models rank candidate queries by popularity (i.e., frequency), and in doing so they tend to follow a strict query matching policy when counting the queries. That is, they ignore the contributions from so-called homologous queries, queries with the same ter...

OBJECTIVES To examine the distribution of all genes known to be responsible for resistance to quaternary ammonium compounds (QACs), and their association with resistance to QACs and other antimicrobials, in Escherichia coli recovered from retail meats. METHODS A total of 570 strains of E. coli isolated from US retail meats in 2006 were screened for the presence of 10 QAC resistance genes [qac...

BACKGROUND Non-tuberculous mycobacteria (NTM) are increasingly important as opportunistic infections after major and minor surgical procedures, likely because they are ubiquitous and not effectively killed by many commonly used disinfectants. Outbreaks of soft tissue infections with NTM appeared related to the use of commercial disinfectants based on quaternary ammonium compounds (QACs). METH...

qAC 0 2] is the class of languages computable by circuits of constant depth and quasi-polynomial (2 log O(1) n) size with unbounded fan-in AND, OR, and PARITY gates. Symmetric functions are those functions that are invariant under permutations of the input variables. Thus a symmetric function f n : f0; 1g n ! f0; 1g can also be seen as a function f n : f0; 1; ; ng ! f0; 1g. We give the followin...

This paper presents the architecture of the Concept-based Vector Space Model Question Answering System (CBVSM-QAS) developed at the Nagaoka University of Technology (NUT) and used in the 4-th NTCIR workshop Question Answering Challenge (QAC) evaluation. The CBVSM-QAS runs on the factual question, which is, correspond to the subtask-1 in the NTCIR-4’s QAC. One major peculiarity of this system is...

Contextual data plays an important role in modeling search engine users’ behaviors on both query auto-completion (QAC) log and normal query (click) log. User’s recent search history on each log has been widely studied individually as the context to benefit the modeling of users’ behaviors on that log. However, there is no existing work that explores or incorporates both logs together for contex...

The choice of analogue ion of the mobile phase additive is shown to significantly affect the analysis of quaternary ammonium compounds (QACs) in ion-pair reversed-phase high-performance liquid chromatography. A series of bromide-containing and dodecyl-sulfate-containing mobile phase additives are investigated using two QAC probe analytes. In all instances, the quaternary-ammonium-containing mob...

The percutaneous absorption of an organosilicon quaternary ammonium chloride (14C)-3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (14C-Si-QAC) was studied in rabbits. Aqueous solution of 14C-Si-QAC was either applied to the intact, clipped back of animals for 10 days or administered by a single intravenous dose. Urine and feces were collected at 24-h intervals and tissue concentr...