The possibility to use a vibration signal to estimate friction processes in sliding couplings

In the article the results of the preliminary vibroacustic research and the stereometry examination of the surface of ball bearings used in the timing belt tensioner pulley of cars were presented. For comparative purposes the research was performed for the group of newly manufactured bearings and for the group of bearings after 110 thousand km mileage of the car. The analysis of the wear process of the rolling bearing elements was showed and also the theoretical study of the vibrations generated during a work of bearing-shaft coupling was discussed. The vibration signal components characteristic for the shaft and the elements of a bearing were described and estimated according to a review of literature. In the article the research program and experimental details of the preliminary signal vibration measurements were explained. The vibration tests (curves of instantaneous values of vibration acceleration during time) were carried out with industrial unit CSI 2130 by Emerson and with accelerometer A0760GP for new bearings and bearings after long operation. The amplitude-frequency signal spectrums were recorded for both group of bearings at the same work conditions, than compared between each other and with calculated characteristic theoretical signal components. During the project the laboratory investigation of the rolling bearings surface stereometry was also conducted. The results revealed the occurrence of the following wear processes: abrasive wear, adhesion-abrasive wear, pitting on the surface of the rollers mating with the bearing race, corrosion wear and also fretting in place of permanent connection. Based on the preliminary research of the rolling bearings used in the timing belt tensioner pulley it was assumed that vibrations spectrum for new bearings and after operation were significantly differed. It confirmed the used test equipment and the methodology of the laboratory tests had sufficient sensitivity and could be applied to the reliability research of other types of rolling bearings at the test stand and could be also used to estimate a key goal and range of the further research projects

The role of polymorphisms of genes encoding collagen IX and XI in lumbar disc disease

The intervertebral disc disease (IDD) is one of the most common musculoskeletal disorders. A number of environment and anthropometric risk factors may contribute to it. The recent reports have suggested the importance of genetic factors, especially these which encode collagen types IX and XI. The allelic variants in the collagen IX genes – COL9A2 (Trp2) and COL9A3 (Trp3) have been identified as genetic risk factors for IDD, because they interfere the cross-linking between collagen types II, IX and XI and result in decreased stability of intervertebral discs. Type XI collagen is a minor component of cartilage collagen fibrils, but it is present in the annulus fibrosus and nucleus pulposus of intervertebral discs. Some studies have shown the association between gene COL11A1 polymorphism c.4603C>T and IDD. The frequency of 4603T allele was significantly higher in the patients with IDD than in the healthy controls

The effect of methyl jasmonate vapors on content of phenolic compounds in seedlings of common buckwheat (Fagopyrum esculentum Moench)

The effect of methyl jasmonate (MJ) vapors on content of phenolic compounds: free phenolic acids, total quercetin, and total phenolics in etiolated buckwheat seedlings were studied. The data presented show that low concentration of MJ (10-8 M) had no influence on trans-cinnamic acid (CA), but stimulated the accumulation of chlorogenic acid in hypocotyls and cotyledons of buckwheat seedlings. A moderate dose of MJ (10-6 M) did not change the level of chlorogenic acid in the hypocotyls and cotyledons, but CA synthesis was promoted in cotyledons, whereas in hypocotyls no significant effect was found. Highest concentration of MJ (10-4 M) caused small decline of CA in hypocotyls, but large stimulation of the acid production in cotyledons was noted. MJ had stimulatory effect on caffeic acid forming, but inhibited synthesis of vanillic acid in hypocotyls and cotyledons. Lowest concentration of MJ (10-8 M) elicited accumulation of quercetin glycosides in both studied tissues of buckwheat seedlings, however at higher doses (10-8 and 10-4 M) did not affect the flavonol level. The obtained results suggest that nonequivalent influence of methyl jasmonate on the phenolics composition can be a result of various mechanisms of MJ uptake, transforming and/or its translocation in buckwheat hypocotyls and cotyledons. Decline of anthocyanins level in buckwheat hypocotyls caused by MJ cannot be explained by enhanced accumulation of quercetin glycosides or free phenolic acids, but probably by synthesis of other unknown phenolic compounds

The influence of selected plant polyamines on feeding and survival of grain aphid (Sitobion avenae F.)

Abstract: The influence of common plant polyamines on feeding behaviour and survival of grain aphid (Sitobion avenae F., Hemiptera: Aphididae) has been studied. Laboratory tests showed that wingless females of S. avenae assimilated higher quantities of food from triticale seedlings placed in 0.01% solutions of agmatine and cadaverine, and lower in case of spermidine and spermine. Increase in the polyamines concentrations up to 0.10% caused strong decrease in food assimilation, especially under the agmatine, cadaverine and putrescine treatment. Moreover, 0.10% concentration of the all analyzed polyamines decreased body mass and reduced survival of grain aphid wingless females. The 0.01% concentration of the polyamines were not affecting survival and body mass of S. avenae with exception of spermidine. Importance of the polyamines as potential natural biopesticides to the grain aphid is discussed

Biodiversity of soil bacteria exposed to sub-lethal concentrations of phosphonium-based ionic liquids: Effects of toxicity and biodegradation

Little is known about the effect of ionic liquids (ILs) on the structure of soil microbial communities and resulting biodiversity. Therefore, we studied the influence of six trihexyl(tetradecyl)phosphonium ILs (with either bromide or various organic anions) at sublethal concentrations on the structure of microbial community present in an urban park soil in 100-day microcosm experiments. The biodiversity decreased in all samples (Shannon's index decreased from 1.75 down to 0.74 and OTU's number decreased from 1399 down to 965) with the largest decrease observed in the microcosms spiked with ILs where biodegradation extent was higher than 80%. (i.e. [P66614][Br] and [P66614][2,4,4]). Despite this general decrease in biodiversity, which can be explained by ecotoxic effect of the ILs, the microbial community in the microcosms was enriched with Gram-negative hydrocarbon-degrading genera e.g. Sphingomonas. It is hypothesized that, in addition to toxicity, the observed decrease in biodiversity and change in the microbial community structure may be explained by the primary biodegradation of the ILs or their metabolites by the mentioned genera, which outcompeted other microorganisms unable to degrade ILs or their metabolites. Thus, the introduction of phosphonium-based ILs into soils at sub-lethal concentrations may result not only in a decrease in biodiversity due to toxic effects, but also in enrichment with ILs-degrading bacteria

Characterization of patients with pulmonary arterial hypertension : data from the polish registry of pulmonary hypertension (BNP-PL)

Current knowledge of pulmonary arterial hypertension (PAH) epidemiology is based mainly on data from Western populations, and therefore we aimed to characterize a large group of Caucasian PAH adults of Central-Eastern European origin. We analyzed data of incident and prevalent PAH adults enrolled in a prospective national registry involving all Polish PAH centers. The estimated prevalence and annual incidence of PAH were 30.8/mln adults and 5.2/mln adults, respectively and they were the highest in females ≥65 years old. The most frequent type of PAH was idiopathic (n = 444; 46%) followed by PAH associated with congenital heart diseases (CHD-PAH, n = 356; 36.7%), and PAH associated with connective tissue disease (CTD-PAH, n = 132; 13.6%). At enrollment, most incident cases (71.9%) were at intermediate mortality risk and the prevalent cases had most of their risk factors in the intermediate or high risk range. The use of triple combination therapy was rare (4.7%). A high prevalence of PAH among older population confirms the changing demographics of PAH found in the Western countries. In contrast, we found: a female predominance across all age groups, a high proportion of patients with CHD-PAH as compared to patients with CTD-PAH and a low use of triple combination therapy