Mechanical and Tribological Properties of TiN Coatings Produced by PIII&D Technique

The structure, mechanical and tribological properties TiN coatings рroduced with PIII&D by using rectilinear filtered vacuum arc plasma system are present. The results of scratch testing and wear reciprocating testing clearly revealed the positive effect of pulse bias (0.5÷2.5 kV) application on tribological behavior of the TiN coatings in comparison the coatings deposited with DC bias (150 V). Application of pulsed bias potential leads to a significant reduction in the friction coefficient and increasing of coatings wear resistance due to a change in their structure. The orientation of crystal planes parallel to the surface changes from (111) to (220) with the application of pulse bias, which is accompanied by a transition from fibrous grains structure to denser columnar grains. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3518

Performance Evaluation of Gradient Routing Strategies for Wireless Sensor Networks

International audienceWe consider Wireless Sensor Networks (WSN) applications in which sensors have to send data to a unique sink in a multi-hop fashion. Gradient routing protocol is a scalable way to route data in these applications. Many gradient routing protocols exist, they mainly differ in their performances (delay, delivery ratio, etc.). In this paper, we propose an extensive performance evaluation study of some gradient routing protocols in order to give guidelines for WSN developers

Test-retest reliability of tetrax® static posturography system in young adults with low physical activity level

Purpose/Background: Assessment of postural sway with force plates can be affected by type of measurement and various clinical parameters such as age and activity level of the individual person. For this reason, variability is detected in postural reactions of healthy subjects without balance impairment. Test-retest reliability of postural sway in adolescent athletes has been measured using a force plate and additional test-retest studies have been suggested for subjects of different age groups with different activity levels. Therefore, the purpose of this research was to assess test-retest reliability of Tetrax (R) Static Posturography in young adults with low physical activity level, and examine the relationship between posturography results and low activity level.Methods: Young adults older than 18 years of age were included in the study. Demographic characteristics of the cases were recorded including age, weight, height, body mass index (BMI, kg/m(2)) and dominant extremity. Number of falls in the previous six months, lower body endurance (sit to stand test) and single-leg eyes closed stance test were recorded. Activity level of participants was determined according to the International Physical Activity Questionnaire (IPAQ). Posturographic evaluation of all volunteers was completed using the Tetrax (R) Interactive Postural Balance System (Sunlight Medical Ltd, Israel). Fall risk and general stability index (SI) calculated by the Tetrax (R) were recorded. Following the first test, measurements were repeated 24 to 48 hours later for reliability purposes.Results: Sixty-five subjects (28 male, 37 female; mean age 22.2 +/- 1.1 years, mean BMI 22.6 +/- 3.3 kg/m(2)) were evaluated. All participants were classified as minimally active according to mean IPAQ score (1042.1 +/- 517.7 [231 -2826] MET-minutes per week). ICC scores between the first and second tests for fall index and total stability index were excellent (ICC2,1 = 0.858, 0.850, respectively). Fall risk determined by using the Tetrax (R) device was negatively correlated with lower body endurance (p=0.001, r=-0.446), vigorous activity score (p=0.011, -0.312) and total activity score (p=0.029, r=-0.271), and positively correlated with single leg stance score (p=0.001, r=0.606). There was a weak correlation between fall risk history and the fall risk determined by using Tetrax (R) device (p=0.04, r=0.255). There were no correlations between fall risk and height, weight, and BMI (p>0.05).Conclusions: The results demonstrated the high test-retest reliability of Tetrax (R) interactive balance system in young healthy adults with low physical activity level. Future studies are needed to determine the effectiveness of increasing physical activity level on postural control

Mechanical and Tribological Properties of TiN Coatings Produced by PIII&D Technique

The structure, mechanical and tribological properties TiN coatings рroduced with PIII&D by using rectilinear filtered vacuum arc plasma system are present. The results of scratch testing and wear reciprocating testing clearly revealed the positive effect of pulse bias (0.5÷2.5 kV) application on tribological behavior of the TiN coatings in comparison the coatings deposited with DC bias (150 V). Application of pulsed bias potential leads to a significant reduction in the friction coefficient and increasing of coatings wear resistance due to a change in their structure. The orientation of crystal planes parallel to the surface changes from (111) to (220) with the application of pulse bias, which is accompanied by a transition from fibrous grains structure to denser columnar grains. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3518

The Transient Ultra-luminous X-ray Source, ULX-4, in M51

We present the results of a temporal and spectral analysis of the transient source ULX-4 in the galaxy M51. The data used were drawn from Chandra, XMM-Newton and Swift-XRT archives, spanning the years 2000-2019. The X-ray flux of the source is seen to vary by two orders of magnitudes within a month but a short-term variability was not observed over the time intervals of 100-2000 second in the 0.3-10 keV energy band. We find some evidence for the existence of bi-modality feature in the flux distribution of ULX-4. We identified two optical sources as possible counterparts within an error radius of 0."18 at 95% confidence level for ULX-4 based on the archival HST/ACS and HST/WFC3 data. Blackbody fits of the spectral energy distributions (SEDs) indicate the spectral type to be B-type stars. One of these counterparts exhibits a low-amplitude optical periodicity of 264 days in the F606W filter; if we assume this apparent periodicity is associated with the orbital motion of the donor, then it is more likely that the donor is a red supergiant satisfying the long periodicity and accretion via Roche-lobe overflow. Consequently, the SED would then have to be interpreted as a superposition of emissions from a cold donor and a hot flow component, most likely from an accretion disk. If, on the other hand, the periodicity is super orbital in nature i.e., due to possible interactions of the compact object with a circumstellar disk, the donor could then be a Be/X star hosting a neutron star.Comment: Accepted for publication in MNRAS. 16 pages, 12 figures, 6 table

Bodipy-based photosensitizers with long alkyl tails at the meso position: efficient singlet oxygen generation in Cremophor-EL micelles

Bodipy dyes with n-decyloxyphenyl-(4, 5) and pentadecyl-(8) meso substituents can easily embed themselves into micellar structures formed from Cremophor-EL. In micelles of approximately 20 nm median size, heavy-atom substituted dyes show remarkable photosensitization properties as evidenced by the rate of reaction with an anthracene-based selective singlet oxygen trap in buffered aqueous solutions. Considering the ease of Bodipy derivatization and the advantages of Cremophor-EL carried therapeutic agents, these photosensitizing agents may offer novel targeting opportunities and enhanced chemical and photophysical stability. © 2016 Elsevier Lt

Evaluation of virulence factors in enterococcus species

Enterococci have recently become important due to their increased isolation rates in community-based and nosocomial infections and resistance to many antibiotics, including glycopeptides. The aim of this study was to evaluate the antimicrobial susceptible patterns and virulence factors of various clinical specimens; urine (n= 149), blood (n= 38), wound (n= 17), stool (n= 13), and other (n= 12) with a total of 229 enterococci including 138 E. faecalis and 91 E. faecium isolates. Aggregation factor (AF), enterococcus surface protein (esp), cytolysins and gelatinase encoding genes (asa1, esp, cylM, cylBcyl A, cylll, cylls, gelE, respectively) were investigated by molecular methods. Haemolysin production and gelatinase were studied phenotypically. A total of 30 isolates, 29 of E. faecium and one of E. faecalis isolates were resistant to vancomycin. High-level gentamicin and high-level streptomycin resistance in E. faecalis were 40.7% and 63.7% however, they were 47.1% and 55.8% in E. faecalis isolates. All strains were susceptible to linezolid. Ampicillin, penicillin and vancomycin resistance in E. faecium isolates were found to be higher than E. faecalis isolates (p= 0.001, p= 0.008 and p< 0.001). Asa1 (p< 0.001), cylll (p= 0.002) and cylls (p< 0.001) as well as gelatinase activity in isolates of E. faecalis were significantly higher than the isolates of E. faecium (p< 0.001). The most common virulence genes in our study were asa1 gene (45%), cyLs gene (33.2%) and esp gene (32.3%). Ciprofloxacin resistance in cylLL and cyLs gene positive isolates of E. faecalis were significantly higher compared to isolates that do not contain these genes (p= 0.035 and p= 0.047). Likewise, haemolysin producing E. faecium isolates were significantly more resistant to vancomycin compared to isolates that do not produce hemolysin (p< 0.001). When the virulence factors of vancomycin resistant and susceptible isolates were compared, the esp gene level in VRE E. faecium isolates was found to be 24.1%, while no esp gene was found in VRE E. faecalis isolates. The existence of asa1was negative in both VRE E. faecium and VRE E. faecalis isolates. The activity of hemolysin was found 42.3% for E. faecalis and 19.3% for E. faecium. In vancomycin-sensitive enterococcus (VSE) species, esp gene activity was 35.1% for E. faecalis, 29.4% for E. faecium, asa1 gene activity was 60.8% for E. faecalis and 47.1% for E. faecium, hemolysin activity was 52.8% for E. faecalis and 23.5% for E. faecium. In our study, it was found that VSE isolates have more virulence genes than VRE isolates. It should be kept in mind that VRE can causeinfections which are difficult-to-treat especially in hospitalized patients and VSE have significant virulence factors that can cause severe infections

Strain hardening behavior of lightweight hybrid polyvinyl alcohol (PVA) fiber reinforced cement composites

Experimental results on the strain hardening and multiple cracking behaviors of polyvinyl alcohol (PVA) fiber reinforced cementitious composites under bending are reported in this paper. Different hybrid combinations of PVA fibers with different lengths and volume fractions are considered to reinforce the mortar matrix. Among different hybrid combinations, the composite containing 2% thicker PVA fibers of 12 mm length and 1% thinner PVA fibers of 6 mm length and the composite containing 2% thicker PVA fibers of 24 mm length and 1% thinner PVA fibers of 6 mm length showed the best performance in terms of highest ultimate load, largest CMOD (crack mouth opening displacement) at peak load and multiple cracking behavior. The effects of four types of light weight sands on the strain hardening and multiple cracking behavior of hybrid fiber composites are also evaluated in this study. It has been observed that the ultimate load and CMOD at peak load for all light weight hybrid fiber composites are almost the same irrespective of volume fractions of light weight sand. The composites containing finer light weight sands exhibited higher ultimate load than those containing coarser light weight sands. It is also observed that the hybrid fiber composite containing normal silica sand exhibited higher ultimate load than the composites with light weight sands