2 research outputs found
Development of a MALDI–TOF MS-Based Protein Fingerprint Database of Common Food Fish Allowing Fast and Reliable Identification of Fraud and Substitution
Fish
substitution and fish fraud are widely observed in the global
food market. To detect and prevent substitution, DNA-based methods
do not always meet the demand of being time- and cost-efficient; therefore,
methodology improvements are needed. The use of species-specific protein
patterns, as determined by matrix-assisted laser desorption/ionization
time-of-flight (MALDI–TOF) mass spectrometry, has recently
improved species identification of prokaryotes both time- and cost-wise.
We used the method to establish a database containing protein patterns
of common food fish prone to substitution. The database currently
comprises 54 fish species. Aspects such as the sensitivity of identification
on the species level and the impact of bacterial contamination of
fish filets are assessed. Most database entries are characterized
by low intraspecies but high interspecies variability. Hitherto, 118
validation samples were successfully determined. The results presented
herein underline the potential and reliability of eukaryotic species
identification via MALDI–TOF mass spectrometry
Ferroelectricity in Simple Binary ZrO<sub>2</sub> and HfO<sub>2</sub>
The transition metal oxides ZrO<sub>2</sub> and HfO<sub>2</sub> as well as their solid solution are widely researched and,
like
most binary oxides, are expected to exhibit centrosymmetric crystal
structure and therewith linear dielectric characteristics. For this
reason, those oxides, even though successfully introduced into microelectronics,
were never considered to be more than simple dielectrics possessing
limited functionality. Here we report the discovery of a field-driven
ferroelectric phase transition in pure, sub 10 nm ZrO<sub>2</sub> thin
films and a composition- and temperature-dependent transition to a
stable ferroelectric phase in the HfO<sub>2</sub>–ZrO<sub>2</sub> mixed oxide. These unusual findings are attributed to a size-driven
tetragonal to orthorhombic phase transition that in thin films, similar
to the anticipated tetragonal to monoclinic transition, is lowered
to room temperature. A structural investigation revealed the orthorhombic
phase to be of space group <i>Pbc</i>2<sub>1</sub>, whose
noncentrosymmetric nature is deemed responsible for the spontaneous
polarization in this novel, nanoscale ferroelectrics