Polyurethane (PU) matrix composites were prepared with various carbon fillers at different filler contents in order to investigate their structure, mechanical and microwave absorbing properties. As ...fillers, flat carbon microparticles, carbon microfibers and multiwalled carbon nanotubes (MWNT) were used. The microstructure of the composite was examined by scanning electron microscopy and transmission electron microscopy. Mechanical properties, namely universal hardness, plastic hardness, elastic modulus and creep were assessed by means of depth sensing indentation test. Mechanical properties of PU composite filled with different fillers were investigated and the composite always exhibited higher hardness, elastic modulus and creep resistance than un-filled PU. Influence of filler shape, content and dispersion was also investigated.
A
bstract
A search for the
K
+
→
π
+
X
decay, where
X
is a long-lived feebly interacting particle, is performed through an interpretation of the
K
+
→
π
+
ν
ν
¯
analysis of data collected in 2017 by ...the NA62 experiment at CERN. Two ranges of
X
masses, 0–110 MeV
/c
2
and 154–260 MeV
/c
2
, and lifetimes above 100 ps are considered. The limits set on the branching ratio, BR(
K
+
→
π
+
X
), are competitive with previously reported searches in the first mass range, and improve on current limits in the second mass range by more than an order of magnitude.
European-Union countries undergo the process of unifying laws. This is also true for protocols designated for monitoring and evaluation of pests and pesticide risks. This study was aimed at exploring ...whether different methods of sampling and extracting pests would lead to different pest population estimation. We compared two methods of sampling (surface sampling with cup-sampler vs. subsurface sampling with spear-sampler) and two methods of pests’ extraction from samples (automated sieving vs. Tullgren apparatus) taken from a highly pest infested flat grain store. Overall eight species of mites, seven species of beetles and two species of psocids were identified. The pest population density ranged between 0–12 individuals per sample (200 g) in psocids, 0–14 in beetles and 2–25060 in mites. Surface sampling with cup-sampler was significantly more effective than sampling using subsurface spear-sampler. The number of trapped species was influenced neither by sampling nor by extracting method. This study revealed variation in pest population density and spatial distribution when estimated by different sampling methods thereby indicating necessity for common European protocol for sampling and detection of storage pests.
Psocids of the genus Liposcelis (Psocoptera: Liposcelididae) are stored product pests that are difficult to identify morphologically. A molecular method based on Restriction Fragment Length ...Polymorphism (RFLP) of the PCR-amplified 16S rDNA gene was developed for the rapid discrimination of four common species (L. bostrychophila, L. entomophila, L. decolor, and L. paeta). Different developmental stages and populations (P.R. China and Czech Republic) were tested. One DNA fragment of about 500 bp in length was amplified from genomic DNA and the fragment was then digested using the restriction endonuclease DraI. Identification of the relevant banding pattern allowed all the developmental stages and both sexes to be discriminated in the species tested. The banding patterns of L. entomophila from all populations were identical, while the relevant restriction digests and sequence analysis confirmed that the Chinese and Czech populations of L. bostrychophila, L. decolor, and L. paeta differed. In conclusion, PCR-RFLP with one pair of primers (16Sar and 16Sbr) and one restrictive endonuclease, DraI, proved to be a reliable method for rapidly discriminating the Liposcelis species tested.
Characterisation of Pasteurella multocida isolated from rabbits in the Czech Republic Jaglic, Z.(Vyzkumny Ustav Veterinarniho Lekarstvi, Brno (Czech Republic)) E-mail:jaglic@vr.cz; Kucerova, Z.(Vyzkumny Ustav Veterinarniho Lekarstvi, Brno (Czech Republic)); Nedbalcova, K.(Vyzkumny Ustav Veterinarniho Lekarstvi, Brno (Czech Republic)) ...
Veterinární medicína,
05/2006, Volume:
51, Issue:
5
Journal Article
Peer reviewed
Open access
Twenty seven Pasteurella multocida rabbit isolates were characterised by pulsed-field gel electrophoresis (PFGE), generated by restriction endonuclease ApaI, examined for the presence of capsule and ...fimbriae, and tested for haemolytic activity and endotoxin release in presence of rabbit plasma. Twenty different PFGE types were observed among the isolates. All isolates were found to be encapsulated, 4 of them also possessed fimbriae. Although the presence of the aphA gene, conferring a haemolytic phenotype for Escherichia coli under anaerobic conditions, was indicated in all of the isolates by PCR, clear haemolytic activity was observed in only one isolate when grown anaerobically. All of the isolates grew easily in the presence of rabbit plasma, which showed a high capacity to bind the released endotoxin.
Due to dramatic effects of even small changes in mobile phase composition on the retention, separations of high-molecular compounds are very difficult, if possible at all, at isocratic conditions and ...need gradient elution. The theory of gradient elution for small molecules is well established, however its applications to reversed-phase gradient separations of biopolymers are not straightforward because of specific problems, such as slow diffusion, limited accessibility of the stationary phase for larger molecules, or possible sample conformation changes during the elution. Theoretical prediction of gradient data needs the parameters of model retention equations to be known, which however cannot be determined at isocratic conditions. The present work overviews the attempts at implementation of the conventional gradient theory developed for low-molecular compounds to the description and prediction of gradient separations of peptides and proteins on various types of HPLC columns: conventional analytical columns packed with wide-pore fully porous, fused-core superficially porous and non-porous particles; silica-based monolithic columns and organic-polymer poly(alkylmethacrylate) and poly(styrene–divinylbenzene) monolithic columns in capillary and disc formats. The attention is focused on the determination of the parameters necessary to predict gradient retention times (volumes) and bandwidths using the theoretical model equations. The accuracy of the prediction of protein retention on totally porous columns improves if size exclusion effect is taken into account, but this is not necessary with non-porous or superficially porous particles. Band dispersion effects counteracting band compression in gradient elution depend on the type of column, on the protein and on the gradient volume (steepness) and complicate the prediction of band broadening in gradient chromatography of proteins, however the conventional gradient model can be employed to estimate the effects of changing gradient parameters on the bandwidths, as well as on the elution times (volumes) of proteins.
The aim of this work was to explore whether the risk of infestation of stored grain by pests is different in various types of storage premises. There was compared the level of infestation and the ...pest species composition in the two main types of grain stores in Central Europe that includes horizontal flat-stores (HFS) and vertical silo-stores (elevators) (VSS). A total of 147 grain stores located in Bohemia, Czech Republic was inspected. We found that both types of stores were infested with arthropods of three main taxonomic groups: mites (25 species, 120 000 individuals), psocids (8 species, 5 600 individuals) and beetles (23 species, 4 500 individuals). We found that VSS and HFS differ in species composition of mites, psocids and beetles. However, the primary grain pests (i.e. Lepidoglyphus destructor, Acarus siro, Tyrophagus putrescentiae, Lachesilla pedicularia, Sitophilus oryzae, Rhyzopertha dominica, Oryzaephilus surinamensis and Cryptolestes ferrugineus) occurred in both types of stores. The only exception was higher frequency and abundance of two serious beetle-pests (Tribolium castaneum, Sitophilus granarius) in HFS than in VSS.
Performance of the NA62 trigger system Cortina Gil, E.; Kleimenova, A.; Minucci, E. ...
The journal of high energy physics,
03/2023, Volume:
2023, Issue:
3
Journal Article
Peer reviewed
Open access
A
bstract
The NA62 experiment at CERN targets the measurement of the ultra-rare
K
+
→
π
+
ν
ν
¯
decay, and carries out a broad physics programme that includes probes for symmetry violations and ...searches for exotic particles. Data were collected in 2016–2018 using a multi-level trigger system, which is described highlighting performance studies based on 2018 data.
A
bstract
Measurement of the ultra-rare
K
+
→
π
+
ν
ν
¯
decay at the NA62 experiment at CERN requires high-performance particle identification to distinguish muons from pions. Calorimetric ...identification currently in use, based on a boosted decision tree algorithm, achieves a muon misidentification probability of 1
.
2 × 10
−
5
for a pion identification efficiency of 75% in the momentum range of 15–40 GeV/
c
. In this work, calorimetric identification performance is improved by developing an algorithm based on a convolutional neural network classifier augmented by a filter. Muon misidentification probability is reduced by a factor of six with respect to the current value for a fixed pion-identification efficiency of 75%. Alternatively, pion identification efficiency is improved from 72% to 91% for a fixed muon misidentification probability of 10
−
5
.
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