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The Influence of Gastrointestinal Nematodes on Modern Sheep Farming and Novel Control Strategies
Get PDFGastrointestinal nematodes represent parasites of great importance in veterinary medicine, especially in grazing animals such as small ruminants. In most cases, these parasites cause subclinical diseases with losses in body weight, reduced feed intake and decreased production. However, high worm burdens may lead to severe clinical signs such as anorexia, anaemia, diarrhoea, protein loss, oedema, decreased immunity and fertility, which can lead to fatal outcomes. Therefore, gastrointestinal nematodes hinder sheep farming in different ways leading to high economic losses that are estimated at several hundred million euros in Europe, although it is difficult to quantify it precisely. An additional problem is the development of anthelmintic resistance in nematodes that occur as a result of irrational use of commercial drugs, whereby the main risk factors are overfrequent treatments, underdosing, the use of only one drug without combination or rotation etc. This leads to a decrease in their effectiveness, and consequently to even higher economic losses (an additional 35-40 million euros). Moreover, these costs will tend to increase in the future due to widespread of resistance and the occurrence of multiresistant strains. For these reasons, the focus of nowadays research is finding alternative solutions including genetic selection of naturally resistant animals, pasture management, dietary manipulation, biological control (use of nematophagous fungi, bacteria or earthworms and dung beetles) and the use of plant-based formulations such as extracts and essential oils. All of the above strategies have shown promise, although it appears that none of them could be used independently. Therefore, future strategies for the control of gastrointestinal nematodes should be based on an integrated approach. This implies the combination of mentioned alternatives with rational use of anthelmintics based on refugia strategies (target treatments and target selective treatments)
The accumulation of manganese by Chlamydomonas acidophila strains isolated from acid mine drainage
Get PDFAcid mine drainage ponds represents a specific artificial ecosystem that gives advantage to extemophilic microalgae. The mechanisms of adaptaton of such strains to excess metal concentrations that are common for their habitat, are poorly understood. Herein, we analzyed two strains of the green microalga Chlamydomonas acidophila - 137 and PM01, which have been isolated from different mining sites, for their interactions with Mn ions. The effects of different concentrations of Mn2+ were investigated in the late exponential/early stationary phase of culture growth (15 days). Viability was determined by Evans blue assay. No toxic effects were observed at concentrations as high as 2 mM Mn2+. The the time dynamics of Mn accumulation in the biomass was determined using ICP. It was shown that the maximum accumulation of Mn in strain 137 (3.79 ± 0.68 μg/mg) was reached at 24h, while for PM01 the highest uptake (3.23 ± 0.17 μg/mg) was observed at 72 h. Next we analyzed redox settings by measuring the levels of reduced thiols unsing in vivo EPR spin probing. The treatment with 2 mM Mn2+ induced a rapid and irreversible decrease in the level of thiols which indicates that Mn2+ activated prooxidtaive processes. The maximum drop of thios levels were: from 4.80 ± 0.05 to 2.70 ± 0.05nmol/mg fresh weight after 1h for 137; and from 4.70 ± 0.05 to 3.40 ± 0.05 nmol/mg fresh weiht after 30 min for PM01. Further, the level of reactive oxygen species was evaluated using fluorescent probe DCFH-DA assay. The changes were in agreement with thiol levels. Both tested algal strains show resistance to Mn and are therefore good candidates for application in water bioremediation
Smart functional polymer-ceramiccomposites for sustainable energy harvesting and storage
Get PDFPolymer-based composites containing insulating inorganic fillers with different functionalities are attracting a great deal of interest for multiple applications, including embedded planar capacitors, flexible piezoelectric harvesters and portable devices for self-powered electronics. They combine typical properties of polymers, such as easy processing at low temperature, flexibility and high breakdown strength (BDS) with the dielectric or piezoelectric properties of some inorganic compounds and, in particular, of ferroelectric perovskites such as BaTiO3, 0.94 Na0.5Bi0.5TiO3 - 0.06 BaTiO3 and Ba1-yCayZrxTi1-xO3. A rational selection of components, good interface engineering and proper processing optimization allows a thorough comprehension of the complex process-structure-morphology-properties relationships of the multicomponent systems. Here, we present our most significant results on PVDF-ceramic composites for energy harvesting and storage. A careful multi-level characterization allows the optimization of the functional properties (dielectric behaviour, piezoelectricity, power density), performance and durability (mechanical strength, flexibility, fatigue resistance) as specifically required for the envisaged final devices
Структурна својства керамике BiFeO3 допиране лантаном и цирконијумом; Structural properties of BiFeO3 ceramics doped with lantanum and zirconium
Get PDFLevels of DDT in sterilized milk
Get PDFMilk is an important source of nutrients for newborns, babies, and children. Sterilized milk is a
nutritional food of modern times and a fast lifestyle. On the other hand, concerns about the safety
of milk date back to the end of the last century. Various sources of contamination can threaten the
safety of milk and the health of children, but also adults. The concern is primarily related to the
presence of pesticides, the main source of which is the feed and the environment. The aim of this
work is to systematize the results obtained from milk control in recent years. Research was carried
out by monitoring the presence of the sum of DDT metabolites in sterilized milk in the period from
2018 to 2022
Activation of Osmium by the Surface Effects of Hydrogenated TiO2 Nanotube Arrays for Enhanced Hydrogen Evolution Reaction Performance
No full textEfficient cathodes for the hydrogen evolution reaction (HER) in acidic
water electrolysis rely on the use of expensive platinum group metals (PGMs). However, to
achieve economically viable operation, both the content of PGMs must be reduced and
their intrinsically strong H adsorption mitigated. Herein, we show that the surface effects of
hydrogenated TiO2 nanotube (TNT) arrays can make osmium, a so far less-explored PGM,
a highly active HER electrocatalyst. These defect-rich TiO2 nanostructures provide an
interactive scaffold for the galvanic deposition of Os particles with modulated adsorption
properties. Through systematic investigations, we identify the synthesis conditions (OsCl3
concentration/temperature/reaction time) that yield a progressive improvement in Os
deposition rate and mass loading, thereby decreasing the HER overpotential. At the same
time, the Os particles deposited by this procedure remain mainly sub-nanometric and
entirely cover the inner tube walls. An optimally balanced Os@TNT composite prepared at
3 mM/55 °C/30 min exhibits a record low overpotential (η) of 61 mV at a current density
of 100 mA cm−2, a high mass activity of 20.8 A mgOs
−1 at 80 mV, and a stable performance in an acidic medium. Density functional
theory calculations indicate the existence of strong interactions between the hydrogenated TiO2 surface and small Os clusters, which
may weaken the Os−H* binding strength and thus boost the intrinsic HER activity of Os centers. The results presented in this study
offer new directions for the fabrication of cost-effective PGM-based catalysts and a better understanding of the synergistic electronic
interactions at the PGM|TiO2 interface
Ductile-to brittle transition of ferritic steels: A historical sketch and some recent trends
No full textThe phenomenon of ductile-to-brittle transition in ferritic steels has been a ubiquitous research challenge
for the last 50 years. The characterization of this problem using the fracture mechanics concept, from the
earliest studies based on the linear-elastic fracture mechanics to the application of the elastic-plastic
fracture mechanics, has become inevitable over time. The fracture toughness is not an intrinsic material
property but depends on geometrical factors (such as the specimen shape, thickness, and surface
roughness), defect type and distribution, loading mode, and environmental conditions. The pronounced
scatter of experimental data on fracture toughness, characteristic of all ferritic steels in the ductile-tobrittle
transition temperature region, necessitated the use of statistical methods for data processing. That
approach, which emerged in the 1970s, can still be found today as the basis for interpreting fracture
toughness data in ductile-to-brittle transition problems. This paper presents a brief historical overview of
such studies along with the problems that have arisen as a consequence of using fracture mechanics
concepts, such as constraint effects, as an example. In the time-honored research tradition, all the
proposed methods and models, as well as their criticisms, provided the basis for the development of new
approaches to the ductile-to-brittle characterization of ferritic steels. Specifically, these include size
effects and scaling of geometrically similar samples, with the aim of predicting material behavior beyond
experimental limits. Brief outlines of two new approaches are provided in this succinct review. The
criticisms of all presented methods are oriented mostly on the application domain, as well as their
capability to predict fracture toughness, with short overview of their most conspicuous advantages and
disadvantages
Activity Coefficients of the System {yNaCl + (1 – y)Na2HPO4}(aq) at T = 298.15 K Determined by Electromotive Force Measurements
No full textThe mean ionic activity coefficients of NaCl in a ternary system {yNaCl + (1 – y)Na2HPO4}(aq)
were determined from measurements of the electromotive force (EMF) where the NaCl ionic strength
fraction was y = (0.3012; 0.4015; 0.5011; 0.5988; 0.7706; 0.8997) in the range of total ionic strength of the
solution Im = 0.0701–1.0161 mol kg–1 at temperature T = 298.15 K. A cell of the Na–ISE| ,Na2HPO4|AgCl|Ag, type was employed for the EMF measurements. The experimental results
from this work and the model of Pitzer’s were used to determine the mixing parameters. Good agreement
was found between the experimental and calculated values of the mean ionic activity coefficients of NaCl
with a standard deviation of fit 1.5 × 10–3. The values of the osmotic coefficients of the system {yNaCl +
(1 – y)Na2HPO4}(aq) were estimated on the basis of the determined parameters and compared with liter ature data. The differences in the osmotic coefficients between the estimated and experimental values were
negligibl
VARIJABILNOST MORFOLOŠKIH KARAKTERISTIKA LISTOVA DIVLJE KRUŠKE (Pyrus pyraster (L.) Burgsd.) NA PODRUČJU PIO „KOSMAJ“
Get PDFDivlja kruška je na prostoru Srbije autohtona vrsta drveća koja je svrstana u
kategoriju vrsta „pod rizikom“. Hibridizacija sa kultivarima koji se uzgajaju za
proizvodnju voća je veoma česta, što otežava identifikaciju čistih divljih voćkarica i predstavlja jedan od ugrožavajućih faktora koji dovode do genetičke erozije
autohtonog genofonda. Cilj rada je utvrđivanje unutarpopulacione varijabilnosti
selekcionisanih test stabala divlje kruške na području Predela izuzetnih odlika
„Kosmaj“, kao osnove za konzervaciju raspoloživog genofonda. Listovi su sakupljeni
sa 16 test stabala selekcionisanih na području Kosmaja (100 listova po stablu), na
kojima su analizirani sledeći kvantitativni i kvalitativni parametri: dužina lisne
ploče, maksimalna širina lista, dužina lisne ploče od osnove lista do dela na kome
je merena maksimalna širina, dužina peteljke, ugao vrha lista, ugao osnove lista,
površina lisne ploče, obim lisne ploče, odnosno oblik lista, oblik osnove lista,
oblik vrha lista, obod lista. Sakupljeni listovi (ukupno 1600) su herbarizovani,
skenirani i izmereni pomoću softvera ImageJ, dok je statistička obrada podataka
urađena pomoću softvera Statgraphics Centurion XVII i Statistica 6.0. Materinsko
stablo 35 se izdavaja u odnosu na druga na osnovu dobijenih prosečnih vrednosti
kvantitativnih parametara, dok se materinsko stablo 27 izdvaja na osnovu kvalitativnih parameter. Rezultati istraživanja pokazali su da su sve dobijene vrednosti
statistički značajne (p < 0,05), što ukazuje na postojanje zadovoljavajućeg stepena
genetičke varijabilnosti između ispitivanih stabala, koji predstavlja dobru osnovu
za očuvanje i usmereno korišćenje genofonda ove vrste
Tuber balkanicum – new taxon defined by molecular, ecological and biogeographical methods
Get PDFTruffle diversity of Balkan Peninsula does not stop to surprise the scientific community with three new species from the melanosporum clade described in last year's (Mereny et al 2017, Milenković at al 2015, Slavova et al 2023). Out of large set of ITS sequences, Mereny at al. (2017) described T. cryptobrumale as connected to Pannonian region, but two other genetically quite distinctive populations were not distinguished as species. In this contribution, we have analyzed larger set of sequences and their habitats and detected strong connection between specimens with specific ITS/LSU region variants to ecologically specific habitats of Balkan peninsula. Soils and vegetation where these specimens have been detected rather resemble descriptions of T. melanosporum sites in Italy, while habitats of T. cryptobrumale resemble those of T. magnatum. Additionally, we have detected numerous populations of T. melanosporum in the coastal regions of Croatia, while this species has never been officially detected eastern from Dinaric alps in Balkan peninsula. We hypothesize that T. melanosporum could never overcome low temperatures of high and long Dinaric massive and is therefore localized in the western Mediterranean regions. This could be the reason why the melanosporum clade has been highly diversifying in Balkan regions. Moreover, the genetic variant widely distributed all over Europe and described as “T. brumale” has never been detected in the Balkans. Therefore, we propose that ecologically and genetically specific taxon that is widespread only in Balkan peninsula (and to some extent northwards) should be recognized as a different species - Tuber balkanicum