The concept of the contact angle in the process of oil film formation in internal combustion piston engines.

In internal combustion piston engines, the process of oil film formation differs from that in industrial machines. The adhesive strength of the molecules at the interface between the coating of engine parts and the lubricating oil affects the load carrying capacity and the ability to form a lubricated film. The geometry of the lubricating wedge between the surfaces of the piston rings and the cylinder wall is determined by the thickness of the oil film and the amount of oil coverage of the ring. This state is modified by many parameters describing the operation of the engine and the physical and chemical parameters of the coatings of the cooperating pairs. For lubricating molecules reaching energies greater than the energy barrier of adhesion at the boundary, sliding occurs. Therefore, the value of the contact angle of the liquid on the surface of the coating depends on the value of the intermolecular force of attraction. According to the author, there is a strong correlation between the contact angle and the lubrication effect. Research indicates that the potential barrier is a function of the contact angle and the contact angle hysteresis (CAH). The innovation of the work consists in the study of the contact angle and CAH in the conditions of thin layers of lubricating oil in cooperation with hydrophilic and hydrophobic coatings. The thickness of the lubricating film was measured under various speed and load conditions using optical interferometry. The study proves that CAH is a better interface parameter to correlate with the effect of hydrodynamic lubrication.

Widespread infection, diversification and old host associations of Nosema Microsporidia in European freshwater gammarids (Amphipoda).

The microsporidian genus Nosema is primarily known to infect insects of economic importance stimulating high research interest, while other hosts remain understudied. Nosema granulosis is one of the formally described Nosema species infecting amphipod crustaceans, being known to infect only two host species. Our first aim was to characterize Nosema spp. infections in different amphipod species from various European localities using the small subunit ribosomal DNA (SSU) marker. Second, we aimed to assess the phylogenetic diversity, host specificity and to explore the evolutionary history that may explain the diversity of gammarid-infecting Nosema lineages by performing a phylogenetic reconstruction based on RNA polymerase II subunit B1 (RPB1) gene sequences. For the host species Gammarus balcanicus, we also analyzed whether parasites were in excess in females to test for sex ratio distortion in relation with Nosema infection. We identified Nosema spp. in 316 individuals from nine amphipod species being widespread in Europe. The RPB1-based phylogenetic reconstruction using newly reported sequences and available data from other invertebrates identified 39 haplogroups being associated with amphipods. These haplogroups clustered into five clades (A-E) that did not form a single amphipod-infecting monophyletic group. Closely related sister clades C and D correspond to Nosema granulosis. Clades A, B and E might represent unknown Nosema species infecting amphipods. Host specificity seemed to be variable with some clades being restricted to single hosts, and some that could be found in several host species. We show that Nosema parasite richness in gammarid hosts is much higher than expected, illustrating the advantage of the use of RPB1 marker over SSU. Finally, we found no hint of sex ratio distortion in Nosema clade A infecting G. balcanicus. This study shows that Nosema spp. are abundant, widespread and diverse in European gammarids. Thus, Nosema is as diverse in aquatic as in terrestrial hosts.

The Theory of the Surface Wettability Angle in the Formation of an Oil Film in Internal Combustion Piston Engines.

In internal combustion piston engines, the formation of an oil film is completely different from that seen in industrial machines. The molecular adhesion force at the interface between the surface coating of engine parts and the lubricating oil determines the load-carrying capacity and the ability to form a lubricated film. The geometry of the lubricating wedge between the surfaces of the piston rings and the cylinder wall is created by the thickness of the oil film and the height of the ring's coverage with lubricating oil. This condition is affected by many of the parameters that characterize the engine's operation and the physical and chemical parameters of the coatings used for the cooperating pairs. For lubricant particles that reach energies that are higher than the potential energy barrier regarding adhesive attraction at the interface, slippage occurs. Therefore, the value of the contact angle of the liquid on the surface of the coating depends on the value of the intermolecular force of attraction. According to the current author, there is a strong relationship between the contact angle and the lubrication effect. The paper shows that the surface potential energy barrier is a function of the contact angle and contact angle hysteresis (CAH). The innovation of the current work consists in examining the contact angle and CAH under the conditions of thin layers of lubricating oil, in cooperation with hydrophilic and hydrophobic coatings. The thickness of the lubricant film was measured under various speed and load conditions, using optical interferometry. The study shows that CAH is a better interfacial parameter for correlation with the effect of hydrodynamic lubrication. This paper presents the mathematical relationships relating to a piston engine, various coatings, and lubricants.

Experimental Studies of Welded Joints in Structures Subject to High Impact Vibrations Using Destructive and Non-Destructive Methods.

This article presents the issues of control and quality assurance of high-strength railway rail joints. Selected test results and requirements for rail joints made by welding with stationary welders on the basis of the requirements included in the PN-EN standards have been described. In addition, destructive and non-destructive tests of weld quality were performed, including visual tests, geometrical measurements of irregularities, magnetic particle and penetration tests, fracture tests, observations of micro- and macro-structure and hardness measurements. The scope of these studies included conducting tests, monitoring the process and evaluating the results obtained. Laboratory tests on the rail joints confirmed the good quality of the rail joints from the welding shop. Increasingly less damage to the track in places of new welded joints is proof that the methodology of laboratory qualification tests is correct and fulfils its task. The presented research will help educate engineers on the welding mechanism and the importance of quality control of rail joints during their design. The results of this study are of key importance for public safety and will improve knowledge on the correct implementation of the rail joint and how to conduct quality control tests in accordance with the requirements of the currently applicable standards. It will help engineers choose the right welding technique and choose solutions to minimize cracks.

A new microsporidian parasite, Microsporidium theragrae n. sp., infecting Alaska pollock Gadus chalcogrammus (Teleostei: Gadidae).

A new microsporidian infecting Gadus chalcogrammus Pallas, 1814 (Gadidae), is described based on morphological, ultrastructural, and molecular studies. This microsporidian parasite develops inside intramuscular spindle-shaped lesions measuring approximately 1-2 mm in width and 4-8 mm in length. Infected cells encapsulated by a host-produced wall containing a sponge-like acellular zone. Sporogony presumably proceeds via segmentation of sporogonial plasmodium, resulting in a variable number of spores. Sporogonial stages develop in sporophorous vesicles (SVs), abutting a moderately electron-dense thick walled coat of a homogeneous amorphous material. SVs space contains rare granular and tubular inclusions. Neighboring SVs often interconnected by bridges of the host cell cytoplasm that were limited by membrane comparable with SV coat. The elongate-ovoid spores, measuring 4.29 ± 0.38 × 2.51 ± 0.26 µm (N 104), possess a bipartite polaroplast and polar tube with 15-16 coils arranged in 2-3 layers. The angle of tilt of the polar tube coils is less than 30°. The sequence analysis of SSU rDNA coding region showed that the studied microsporidians differs from other fish muscle-infecting species at least in 17 bp (2.58%) and is closely related to Microsporidium cypselurus Yokoyama et al. (2002) infecting the flying fish from East China Sea. The parasite is provisionally positioned as Microsporidium theragrae sp. n.

Prediction of slope stability using Tree Augmented Naive-Bayes classifier: modeling and performance evaluation.

Predicting slope stability is critical for identifying terrain that is prone to landslides and mitigating the damage caused by landslides. The relationships between factors that determine slope instability are complicated and multi-factorial, so it is sometimes difficult to mathematically characterize slope stability. In this paper, new Tree Augmented Naive-Bayes (TAN) model was developed to predict slope stability subjected to circular failures based on six input factors: cohesion, internal friction angle, pore pressure ratio, slope angle, unit weight, and slope angle. A total 87 slope stability case records obtained from published literature was used to train and test the proposed TAN model. According to the results of the performance indices-accuracy, precision, recall, F-score and Matthews correlation coefficient, the established TAN model was proven to be better at predicting slope stability with acceptable accuracy than other formerly developed empirical models in the literature. Furthermore, the slope height was revealed as the most sensitive factor in a sensitivity analysis.

Experimental Analysis of the Influence of the Application of TiN, TiAlN, CrN and DLC1 Coatings on the Friction Losses in an Aviation Internal Combustion Engine Intended for the Propulsion of Ultralight Aircraft.

Currently, there are many methods of reducing the friction losses of the main components of an internal combustion piston engine. The operating conditions of internal combustion piston engines intended for the propulsion of ultralight aircraft differ significantly from those prevailing in the case of using these engines for the propulsion of vehicles. There are many studies on the influence of selected anti-wear coatings on the friction coefficients when using various lubricants, measured via tribometers. Unfortunately, the conditions obtained in the laboratory significantly differ from those prevailing in an engine operating under external conditions. The study investigated the influence of a change in the tribological parameters of TiN, TiAlN, CrN and DLC1 anti-wear coatings on the moment of resistance to the piston movement of an aircraft engine. The operating parameters of a real engine working in an aircraft were simulated. The main focus was on the coating layers of the sliding surfaces of the piston rings and the cylinder running surface. The properties of the coatings affect the correlation of the scale of the adhesion and cohesion phenomena of the oil to the opposite planes, and this determines the nature of the changes in the moment of resistance to engine motion. As it is commonly known, with an increase in the value of the maximum pressure of the working medium in the combustion chamber, the share of mixed friction in liquid friction increases, similar to the high oil temperatures occurring in aircraft engines. Therefore, there is a justified need to supplement the research in the field of analyzing the characteristics of the torque of resistance to motion for these engines, in particular in the field of the usable rotational speeds of the crankshaft. Applicable anti-wear systems based on selected coatings can significantly improve operational safety and noticeably reduce fuel consumption.

A response to comment on prognostic factors in burns.

We would like to thank Dr Ewington et al. for the commentary on our review about prognostic factors in burns. First we would like to comment on the role of frailty in assessment of burns. The elderly population is of special interest in all fields of clinical medicine, owing to the ageing of the world population [1]. The definition of frailty is relatively concise. It is defined as a state of depletion of the homeostatic reserve due to changes accumulated during lifetime. In consequence, resolution of stressor sequelae is impaired [2]. Although the definition is straightforward, the methods of its application and quantification of frailty are not unequivocally accepted [3]. Ward and Romanowski in their papers used the Clinical Frailty Scale [4]. Other developed scales, to mention only a few, are the general Korean Frailty Index for Primary Care [5], the Modified Frailty Index 5 (mFI-5) [6], the more specialized Emergency General Surgery Frailty Index [7], and the Burn Frailty Index [8]. Some of them were evaluated in surgery patients, and the Burn Frailty Index was developed by Maxwell specifically to be used in burn patients [8]. A study comparing the usefulness of various frailty scales in a burn ward would be a welcome addition to the discussion about burn outcomes. We would also like to address one more aspect of frailty. Generally, the term is connected with the elderly population, i.e. more than 65 years old. This is based on the fact that one's frailty is a sum of deficits accumulated over the whole lifetime [9]. Yet even in younger age groups various tools used to assess frailty show a relatively high percentage of frail people [10, 11]. Research including patients undergoing orthopaedic surgery has proven that frailty assessment is a viable choice to predict complications even in younger groups [12]. Therefore we assume that frailty indexes will gradually become tools used also in younger groups of patients.

Molecular detection of Trypanosoma spp. in Lipoptena cervi and Lipoptena fortisetosa (Diptera: Hippoboscidae) and their potential role in the transmission of pathogens.

The family Hippoboscidae is a less known group of blood-sucking flies. Deer ked are particularly important for animal health; they may act as potential vectors of disease to ungulates, and may transmit pathogens to animals and humans. The aim of this study was to investigate the presence of Trypanosoma (Megatrypanum) DNA in deer keds using molecular methods. Results prove the presence of Megatrypanum trypanosome DNA in the studied winged adult deer keds and this is the first detection of this pathogen in Lipoptena fortisetosa. In addition, this paper evidences the occurrence of L. fortisetosa in two new locations: one in the Bialowieza Primeval Forest, and another in the Strzalowo Forest Inspectorate (Piska Forest), both in north-eastern Poland.

Prognostic factors in patients with burns.

There are many various medical scales used in different clinical situations for scoring and prognostication the disease outcome. Burns are a group of heterogeneous disorders, which, depending on severity, may be treated in various settings - from outpatient clinic to intensive care units. Consequently they are also associated with different outcome. Over the years many scales and models were created to assess the prognosis and, in consequence, to help choosing the mode of treatment. Simultaneously constant improvement in intensive care reduces the predictive value of older models. In this paper authors searched the available literature for prognostic factors in burn patients as well as for clinical scales based on that disease.

Is inhaled heparin a viable therapeutic option in inhalation injury?

Inhalation injury is a major cause of morbidity and mortality in patients with burns. Presence of airways injury adds to the need of fluid supplementation, increases risk of pulmonary complications. Due to many mechanisms involved in pathophysiology the treatment is complex. Among them the formation of fibrin casts inside airways constitutes a prominent element. The material residing in tracheobronchial tree causes ventilation-perfusion mismatch, complicates mechanical ventilation, provides a medium for bacterial growth. Many studies of animal models and single centre human studies investigated inhaled anticoagulation regimens employing heparin in management of inhalation injury. Simultaneously safety, especially in connection with possible bleeding risk, was the subject of research. The results suggest positive impact on treatment results, with low risk of side effects. This paper revise the available clinical data on inhaled heparin use in patients with burns.

Europe-wide reassessment of Dictyocoela (Microsporidia) infecting native and invasive amphipods (Crustacea): molecular versus ultrastructural traits.

Microsporidia are common parasites infecting animals and protists. They are specifically common pathogens of amphipods (Crustacea, Malacostraca), with Dictyocoela spp. being particularly frequent and highly prevalent, exhibiting a range of phenotypic and ecological effects. Until now, seven species of Dictyocoela were defined, predominantly based on the genetic distance. However, neither the taxonomic status of this provisionally erected genus (based on eight novel sequences and one micrograph of the spore), nor its internal phylogenetic relationships have been clearly revealed. The formal description of the genus and of most of the putative species are still lacking. Here we aimed to fill this gap and performed both ultrastructural and molecular studies (based on SSU, ITS and partial LSU) using different species delimitation methods. As a consensus of these results and following conservative data interpretation, we propose to distinguish five species infecting gammarid hosts, and to keep the names introduced by the authors of the type sequences: Dictyocoela duebenum, D. muelleri, D. berillonum and D. roeselum. We provide full descriptions of these species. Moreover, thanks to our extensive sampling, we extend the known host and geographic range of these Microsporidia.

Study of Loma acerinae (Microsporidia) detected from three Ponto-Caspian gobies (Gobiidae) in Ukraine.

A previously recognized Glugea-belonging Microsporidia (G. melanostomi, G. markievichi, G. naidenovi) were found in the intestinal mucosa of Neogobius melanostomus, N. fluviatilis, and Proterorhinchus semilunaris (Teleostei, Gobiidae) from lower Dnieper River and Black Sea coastal inlets, Ukraine. Light microscope observations demonstrated small spherical xenomes about 0.35 mm in diameter filled by developmental stages of parasites. Mature spores were ellipsoidal, slightly narrowed at anterior pole, sometimes ovoid or elongate in shape approximately 3.1-4.5 × 2.0-2.9 µm in size. The stained spores were elongate ovoid that are measured about 2.3-4.3 × 1.6-3.4 µm. Ultrastructural study showed that xenoma wall consisted of finely granular layer up to 350 nm wide. Numerous host-derived collagenous fibers adhered to the xenoma wall were noticed. Microtubular inclusions about 40 nm in diameter occupied the episporontal space. Mature spores displayed the polar filament arranged in one row. One to two last turns of polar filament were sharply tapered to half of diameter. The number of polar filament turns varied depending of host infected from 10 (9 + 1) in N. melanostomus to 13 (11 + 2) in N. fluviatilis and 14 (13 + 1) in P. semilunaris. The endospore thickness varied depending of host infected from 30-35 nm in case of N. fluviatiis to 40-50 nm in P. semilunaris and 60-80 nm in N. melanostomus. SSU 16S rRNA sequence analysis, blast searches, and ultrastuctural data revealed similarity of all studied microsporidians with Loma acerinae (Jirovec, 1930).

The role of particular ticks developmental stages in the circulation of tick-borne pathogens in Central Europe. 4. Anaplasmataceae

In Central European conditions, two species of Anaplasmataceae have epidemiological significance ­ Candidatus Neoehrlichia micurensis and Anaplasma phagocytophilum. Tick Ixodes ricinus is considered as their main vector, wild mammals as the animal reservoir. There is presented the transstadial transmission in ticks, due to the lack of transovarial mode the circulation goes mainly between immature ticks and hosts; pathogen circulates primarily in the cycle: infected rodent → the tick larva → the nymph → the mammal reservoir → the larva of the tick. The tick stages able to effectively infect human are nymphs and adult females, males do not participate in the follow transmission. The summary of available data of different A. phagocytophilum strains associations with different hosts revealed at least few distinct enzootic cycle, concern the same ticks species and different mammal hosts. It is possible to reveal in Central Europe the existence of at least three different epidemiological transmission cycles of A. phagocytophilum. The first cycle involves strains pathogenic for human and identical strains from horses, dogs, cats, wild boars, hedgehogs, possibly red foxes. The second cycle involves deer, European bison and possibly domestic ruminants. The third cycle contains strains from voles, shrew and possibly Apodemus mice. In Western Europe voles might be involved in separate enzootic cycle with Ixodes trianguliceps as the vector.

Coordinated increase of miRNA-155 and miRNA-196b expression correlates with the detection of the antigenomic strand of hepatitis C virus in peripheral blood mononuclear cells.

A tight relationship has been revealed between cellular microRNAs (miRNAs) and the course of hepatitis C virus (HCV) replication in human hepatoma cells. Although the detection of the antigenomic HCV RNA strand in peripheral blood mononuclear cells (PBMCs) has provided evidence for viral replication in PBMCs, no reports have shown how miRNAs are affected upon HCV RNA synthesis in PBMCs. The aim of the present study was to assess if and how the expression levels of miRNA-155 and miRNA-196b in PBMCs are related to HCV replication in PBMCs of chronic hepatitis C (CHC) patients. Supporting analyses were performed to evaluate the expression of precursor pri-miR-155 (BIC) and Dicer protein. The genomic and antigenomic HCV RNA strands in PBMCs were detected by strand-specific qRT-PCR. The expression levels of miRNAs, BIC RNA and Dicer protein were assayed on PBMCs by qRT-PCR and Western blotting, respectively. miRNA-155 and miRNA-196b were detected in all studied PBMC samples, but their levels varied according to the presence of the antigenomic HCV RNA strand in PBMCs. Increased expression levels of miRNA-155 and miRNA-196b were associated with the presence of the antigenomic HCV RNA strand in PBMCs. In this group of patients higher frequency of BIC RNA and Dicer protein detection was also found. This study demonstrates that HCV RNA replication in PBMCs of CHC patients is connected with the increased and coordinated expression of miRNA-155 and miRNA-196b.

[Respiratory tract burn injuries]. / Oparzenia dróg oddechowych.

Respiratory tract burns are one of the most serious injuries of human organism. They often accompany severe skin burns, increasing morbidity and mortality. Pathologic events happening in the lungs in the course of inhalation injury consist of: edema and necrosis of bronchial mucosa, increase of bronchial blood flow and vascular permeability, recruitment of inflammatory mediators, and obturation of bronchial tract with the casts composed of mucus, tissue debris, neutrophils and fibrin. The above mentioned processes lead to progressive disturbances of pulmonary gas exchange and tissue hypoxia. Introduction of standardized bronchoscopic procedures resulted in the possibility of early diagnosis and treatment of inhalation injuries. There are many treatment options, some of them combined with early and late complications, the optimal treatment protocol is still lacking. Early hyperbaric oxygen therapy is one of the most promising methods of treatment leading to decrease of mortality due to inhalation injury.