Comparative clinico-pathological observations in young Zebu (Bos indicus) cattle experimentally infected with Trypanosoma vivax isolates from tsetse infested and non-tsetse infested areas of Northwest Ethiopia

BACKGROUND: The Northwest region of Ethiopia is affected by both tsetse and non-tsetse transmitted trypanosomosis with a huge impact on livestock productivity. The objective of this experimental study was to determine clinical and pathological findings in young Zebu cattle experimentally infected with Trypanosoma vivax isolates from tsetse infested and non-tsetse infested areas of Northwest Ethiopia. A total of 18 cattle (Bos indicus) aged between 6 and 12 months, purchased from a trypanosome-free and confirmed to be trypanosome negative divided into three groups of six animals were used. Animals in the first two groups (Group TT: tsetse infested isolate infected and Group NT: non-tsetse infested isolate infected) received 2 mL of infected blood from donor animals at 10(6) trypanosomes/mL, and the remaining group was non-infected control (NIC). Each group was observed for a period of eight consecutive weeks, daily for clinical signs and once per week for parasitaemia. Postmortem examinations were done on euthanized animals, and tissue samples were taken for histopathological analysis. RESULTS: The prepatent period of the disease was earlier in the NT group 6 days post infection (dpi) than TT group 12 dpi. The infection was characterized by reduced feed intake, intermittent pyrexia and parasitaemia, enlarged lymph nodes, lacrimation, reduced feed intake and emaciation. Less frequently diarrhea, oedema and nervous signs were observed in both groups of infected animals. At necropsy, infected animals showed enlarged spleen, enlarged lymph nodes, pneumonic and emphysematous lung, enlarged liver, and haemorrhages on the brain and intestine. Histopathological analysis revealed lymphoid hyperplasia of the spleen, necrosis of the liver, encephalitis and hyperplasia of lymph nodes. CONCLUSION: Trpanosoma vivax isolates from both tsetse infested and non-tsetse areas showed a variety of virulence factors leading to the development of acute clinical signs, gross and histopathological lesions. However, the parasitaemia and clinical signs appeared earlier in the NT compared to TT infected groups

In vitro antileishmanial and antischistosomal activities of anemonin isolated from the fresh leaves of Ranunculus multifidus forsk

Leishmaniasis and schistosomiasis are neglected tropical diseases (NTDs) infecting the world's poorest populations. Effectiveness of the current antileishmanial and antischistosomal therapies are significantly declining, which calls for an urgent need of new effective and safe drugs. In Ethiopia fresh leaves of Ranunculus multifidus Forsk. are traditionally used for the treatment of various ailments including leishmaniasis and eradication of intestinal worms. In the current study, anemonin isolated from the fresh leaves of R. multifidus was assessed for its in vitro antileishmanial and antischistosomal activities. Anemonin was isolated from the hydro-distilled extract of the leaves of R. multifidus. Antileishmanial activity was assessed on clinical isolates of the promastigote and amastigote forms of Leishmania aethiopica and L. donovani clinical isolates. Resazurin reduction assay was used to determine antipromastigote activity, while macrophages were employed for antiamastigote and cytotoxicity assays. Antischistosomal assays were performed against adult Schistosoma mansoni and newly transformed schistosomules (NTS). Anemonin displayed significant antileishmanial activity with IC50 values of 1.33 nM and 1.58 nM against promastigotes and 1.24 nM and 1.91 nM against amastigotes of L. aethiopica and L. donovani, respectively. It also showed moderate activity against adult S. mansoni and NTS (49% activity against adult S. mansoni at 10 microM and 41% activity against NTS at 1 microM). The results obtained in this investigation indicate that anemonin has the potential to be used as a template for designing novel antileishmanial and antischistosomal pharmacophores

Tribological behaviour of ARC sprayed coatings made of Fe-Cr-B-Al cored wires under the service conditions of the http valve spindles

Досліджено трибологічну поведінку електродугових покриттів із ПД системи Fe-Cr-B-Al за робочих умов штоків запірних вентилів ТЕС. Встановлено, що коефіцієнт тертя досліджуваних покриттів за умов сухого тертя та прикладеному навантаженні більше 4 МПа є таким же, як і для сталі ШХ 15. Виявлено, що дані покриття добре працюють у контакті з графітовим ущільненням. Також виявлено позитивний вплив просочування електродугових покриттів синтетичними оливами для умов роботи сухого тертя, що зумовлено їхньою структурою, і не залежить від системи легування.The tribological behavior of arc sprayed coatings made of Fe-Cr-B-Al cored wires has been investigated under the service conditions of the heat power plant valve spindle. The arc sprayed coatings have a characteristic lamella structure, lamellas being the solidified droplets separated by oxide films of different nature and thickness, the grinded surface of which is the composite –in the matrix from steel lamellas the particles of oxide phases are available, therefore the structure of such coatings causes their special tribological behavior. It was investigated, that in the dry friction condition under loading of 2 MPa, the friction coefficient of the ШХ 15 steel is lower than for the coating obtained from Fe-Cr-B-Al cored wire, and is equal to 0.32, and under loading more than 4 MPa it equals 0.42. It testifies that under loading less than 2 MPa the tribological properties of ШХ 15 steel are better, however with the increase of loading this phenomenon is not available. It was suggested to investigate the influence of solid lubricant CaF2 on the friction coefficient behavior of arc sprayed coatings made of Fe-Cr-B-Al cored wires. The adding of the CaF2 powder to the mixture of cored wires provides the change of the coating friction coefficient and its behavior is similar to the behavior of the ШХ 15 steel friction coefficient, but, nevertheless, the nominal values are too high and under loading – 5 MPa it equals 0.4. It was found that under the dry friction condition when the loading was 5-6 MPa the temperature on the surface of the coating equals 250-300ºС and the oxide films are formed there. The oxide film is formed on the surface on steel – less-alloyed Cr, on coatings – much-alloyed Cr. In the friction tests these oxide films break and form abrasive particles which cause the significant abrasive wear of both, coating and counterbody – 3X13 steel. It was found that such coatings have very low values of friction coefficients – 0.12-0.15 under conditions of the dry friction in contact with counterbody with built-in graphite. Moreover, with the increase of loading from 2 to 10 MPa the friction coefficient decreases. It was explained by the fact that arc sprayed coatings have on its surface pores and the graphite is accumulated in them during friction and then it forms the boundary friction film on the friction surface. It was found that during wear resistance tests the ШХ15 steel wears the least but its counterdody made of 3X13 steel is subject to significant wear under the dry friction condition, therefore the total wear of this friction pair is higher than for the arc sprayed coating. The positive influence of sealing arc sprayed coatings with synthetic oil was revealed too for the dry friction condition. It was determined that sealing of arc sprayed coatings made of Fe-Cr-B-Al cored wires with synthetic oil Synth 5W40 provides the increasing of their wear resistance in 12 times as compared with those made of ШХ 15 steel and in 9 times as compared with unsealed coatings. The sealed arc sprayed coatings made of Fe-Cr-C-Al cored wires provide the increase of their wear resistance in 9 times in comparison with ШХ 15 steel and in 5 times as compared with unsealed coatings. Such influence of sealing coatings with oil on their wear resistance is likely to be caused by their structure which depends on spraying parameters and doesn’t depend on their alloying system