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"Zmuda, Piotr"
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Preparation and Properties of PETG Filament Modified with a Metallic Additive
The materials used as filaments for additive techniques should exhibit various properties depending on the application and the requirements. The motivation for this study was the need to obtain a filament exhibiting appropriate aesthetic (metal-like) and mechanical properties. Glycol-modified poly(ethylene terephthalate) copolymer (PETG) and micrometric steel powder were used for composite preparation. Subsequently, the obtained material was used as a filament for 3D printing, i.e., by fused deposition modeling (FDM) technique. The physicochemical properties of the obtained filaments were determined, such as morphology (roughness), moisture sorption ability, thermal properties, and mechanical performance (tensile and compressive strength). Importantly, the metal filler did not modify the thermal properties of the polyester matrix, indicating that the filament containing steel microfiller could be processed using the same parameters as for neat PETG. The thermal stability was slightly enhanced after steel powder addition (for 13 wt.% content, the temperature of 75% weight loss was 466 °C; for comparison, that for the reference sample was 446 °C). The reinforcing effect of steel microfiller was noted based on mechanical performance measurements. The steel particles acted as a stiffening agent; the highest maximal tensile strength was observed for the composite with 3 wt.% steel powder content (ca. 68 MPa). Further increasing the microfiller load resulted in a slight decrease in the value of this parameter. A different trend was reported considering the compressive strength, i.e., the value of this parameter increased with steel content. Based on the obtained results, the new PETG composites could be applied as structural materials.
Journal Article
The preliminary assessment of using the artificial neural networks to diagnose ketosis in Polish Red cattle based on β-hydroxybutyric acid and haematological parameters
Polish Red (PR) cows belong to an autochthonous conservation breed, kept mainly in the sub-mountain regions of southern Poland. The breed is characterized by good health, but it is susceptible to metabolic disorders such as ketosis. This type of metabolic disease is primarily diagnosed through analyses of β-hydroxybutyric acid (BHB) in milk or blood. Haematological parameters during ketosis might have change and also, be crucial for detecting ketosis as a metabolic disorder. However, limited research study has examined how these parameters change during ketosis onset. The aim of this preliminary study was to use the BHB and haematological parameters to detect cows at risk of subclinical ketosis in PR cattle breed using an artificial neural network (ANN) Multi-Layer Perceptron (MLP) model. The 45% of the animals analysed had elevated plasma BHB concentrations ranging from 0.86 to 6.7 mmol/L. The sensitivity analysis showed satisfied relevance for haematological parameters like lymphocyte count, haemoglobin levels, and blood cells. The effects of the MLP model were verified by the area under the curve (AUC), which was equal to AUC = 0.633 for lymphocytes, AUC = 0.631 for red blood cells volume, and AUC = 0.616 for haemoglobin. Therefore, the novel findings prove the haematological parameters are accurate to build the MLP-ANN model. However, a new bigger data set, and more information criteria are needed in the future work to provide guidance on the choice of the most appropriate MLP-ANN architecture to detect cows with ketosis.
Journal Article
Genetic analysis reveals the genetic diversity and zoonotic potential of Streptococcus dysgalactiae isolates from sheep
Streptococcus dysgalactiae
(
S. dysgalactiae
) is a common pathogen of humans and various animals. However, the phylogenetic position of animal
S. dysgalactiae
isolates and their zoonotic potential remain unclear. Most molecular epidemiological studies explicate beta-hemolytic streptococci according to their MLST and M protein gene (
emm
) types. Although human
S. dysgalactiae
isolates are relatively well characterized, the data concerning animal isolates are scarce. Here, we report the molecular characteristics and antimicrobial resistance of
S. dysgalactiae
strains recovered from sheep and their genetic relationship with isolates from other animal hosts and humans. Overall, 11 PFGE pulsotypes, five MLST sequence types (STs), and two
emm
types were distinguished, with ST248 and
stL1376
being the most prevalent, indicating genetic diversity among tested 17 ovine isolates. Some isolates exhibited resistance to doxycycline (59%), erythromycin (6%), ciprofloxacin (6%), and trimethoprim/sulfamethoxazole (6%), harboring various resistance determinants. Phylogenetic analysis showed that studied ovine isolates grouped together with human
S. dysgalactiae
isolates from the cases of zoonotic infections. Moreover, some ovine isolates shared identical STs and
emm
gene sequences with human non-invasive and invasive
S. dysgalactiae
strains. These findings suggest a possible link between human and ovine isolates and indicate the zoonotic potential of this pathogen.
Journal Article
Q fever as a potential cause of abortions in sheep (Ovis aries) in the Malopolskie Province – a preliminary study
Q fever is a dangerous zoonosis caused by Coxiella burnetii. The disease occurs mainly in ruminants and may cause reproductive system disorders, including abortions in sheep. Therefore, following an increase in the abortion rate in a village in the Małopolska Region which was investigated for C. burnetii. In 2019 and 2021. Blood was collected from 177 ewes from seven herds, as well as vaginal swabs and milk from 100 ewes. The obtained serum samples were tested with commercial serological ELISA, and the swabs and milk subjected to PCR testing. Of the 177 tested sheep, 23 (13%) were seropositive. The risk of seropositivity was positively correlated with age, but this relationship was weak. All samples were PCR negative. Hence, C. burnetii seems not to be the main cause of abortions in this region. However, due to the high consumption of unpasteurized sheep milk products in this region, further research is needed, particularly regarding agents with zoonotic potential.
Journal Article
Microbiological assessment of sheep lymph nodes with lymphadenitis found during post-mortem examination of slaughtered sheep: implications for veterinary-sanitary meat control
Background
Microbiological examination of lesions found in slaughtered animals during meat inspection is an important part of public health protection as such lesions may be due to zoonotic agents that can be transmitted by meat. Examination of inflamed lymph nodes also plays a particular important role, as lymphadenitis may reflect a more widespread infection. Such lesions in sheep are mainly caused by pyogenic bacteria but also mycobacteria are occasionally found. Meat inspection data from 2017 to 2018 from southern Poland, especially from the Małopolska region, indicate that purulent or caseous lymphadenitis involving the mediastinal and tracheobronchial lymph nodes (MTLNs) is a common finding. The primary aim of the current study was to determine the aetiology of these lesions. Furthermore, it was investigated how presence of lesions was correlated with age and grazing strategy of affected sheep.
Results
Post
-
mortem
examination revealed purulent or caseous lymphadenitis in the MTLNs of 49 out of 284 animals (17.3%). Subsequent microbiological examination revealed the presence of
Corynebacterium pseudotuberculosis
(34.7%),
Streptococcus dysgalactiae
subsp.
equisimilis
(34.7%),
Staphylococcus aureus
(8.2%),
Enterococcus
spp. (2.0%),
Trueperella pyogenes
(2.0%), and β-haemolytic strains of
Escherichia coli
(2.0%).
Mycobacterium
spp. and
Rhodococcus equi
were not detected. In older sheep, the probability of the presence of purulent or caseous lymphadenitis was higher than in younger, and the risk was increasing by 1.5% with each month of life. Sheep grazing locally had 4.5-times greater risk of having purulent or caseous lymphadenitis than individuals summer grazing in the mountains.
Conclusion
The most common aetiological agents of purulent or caseous lymphadenitis in the MTLNs of sheep in the Małopolska region were
C. pseudotuberculosis
and
S. dysgalactiae
subsp.
equisimilis
. Particular attention during
post
-
mortem
examination should be paid to the carcasses of older sheep and sheep grazing on permanent pastures, as they seem more prone to develop purulent or caseous lymphadenitis.
Journal Article
Epidemiological characterization of Mycobacterium caprae strains isolated from wildlife in the Bieszczady Mountains, on the border of Southeast Poland
Background
The majority of animal tuberculosis (TB) cases reported in wildlife in Poland over the past 20 years have concerned the European bison inhabiting the Bieszczady Mountains in Southeast Poland: an area running along the border of Southeast Poland. As no TB cases have been reported in domestic animals in this region since 2005, any occurrence of TB in the free-living animals inhabiting this area might pose a real threat to local livestock and result in the loss of disease-free status. The aim of the study was to describe the occurrence of tuberculosis in the wildlife of the Bieszczady Mountains and determine the microbiological and molecular characteristics of any cultured strains. Lymph node samples were collected for analysis from 274 free-living animals, including European bison, red foxes, badgers, red deer, wild boar and roe deer between 2011 and 2017. Löwenstein–Jensen and Stonebrink media were used for culture. Molecular identification of strains was performed based on
hsp65
sequence analysis, the GenoType®MTBC (Hain Lifescience, Germany
)
test, spoligotyping and MIRU-VNTR analysis.
Results
Mycobacterium caprae
was isolated from the lymph nodes of 21 out of 55 wild boar (38.2%; CI 95%: 26.5%, 51.4%) and one roe deer. Since 2014, no new TB cases have been reported in the Bieszczady European bison population.
Conclusions
The identification of TB in wild boar in the Bieszczady is an alarming phenomenon, which requires further investigation. The Bieszczady mountains are a precious, unique area, home to many protected species. However, it is also the only area in Poland where TB cases have been reported in free-living animals. The occurrence of TB in wild boar inhabiting this area might pose a real threat to local livestock and many of the protected species (for example European bison that can share feeding places with wild boar). Given this situation, ongoing monitoring of the prevalence of TB should be conducted, and protective measures should be considered.
Journal Article
