Experimental study of carbon nanotubes in high viscosity lubricants

Carbon nanotubes (CNTs) beneficial tribological properties were reported in numerous studies performed mostly in idealized tribometer conditions, previously described full engine tests confirmed that CNTs added to the lubricating oil reduced friction significantly. Apparently the engine application requires low CNT concentration in oil, otherwise when increasing the CNT concentration beyond a certain level oil viscosity increases, rapidly forming a greasy substance not suitable for engine lubrication. In this paper we report a study of tribological properties of such a high viscosity lubricant performed in Amsler tribometer in comparison to high quality commercially available lithium grease. The CNT based high viscosity lubricant in its current formulation turned out as not reliable for general application due to its low adhesion to the metal surface. In contrary to some samples made of a polymer widely used in industry as a friction component, we observed wear reduction reaching nearly 50% when replacing the best suitable lithium grease by a CNT based lubricant. This effect was first observed after 30 min into a friction test, suggesting a CNT related mechanism of anti-wear protection which still need to be explained

Selected issues of tribological processes in road transport influence

his article investigates the issue of the environmental impact of car transport. This topic is discussed in the context of tribological processes, which result in increased fuel consumption and consequently increased emissions of exhaust gas components. Based on data found in the literature, the share of frictional resistance in the total fuel consumption of individual cars, trucks and buses was determined. Using statistical data for Poland, the effects of friction processes in individual vehicle groups on the annual CO2 emissions from transport vehicles were also determined. The final part of the paper presents the results of the preliminary research on the possibility of lowering the friction resistance in various friction nodes found in motor vehicles by introducing carbon nanomaterials into the lubricating oils.Artykuł poświęcony jest zagadnieniom uciążliwości transportu samochodowego dla środowiska. Problematyka ta omówiona jest w kontekście procesów tribologicznych, których efektem jest zwiększone zużycie paliwa i w konsekwencji zwiększona emisja składników gazów spalinowych. Na podstawie danych literaturowych określono udział oporów tarcia w poszczególnych zespołach samochodów osobowych, ciężarowych i autobusów w sumarycznej konsumpcji paliwa. Wykorzystując dane statystyczne dla Polski określono wpływ procesów tarcia w poszczególnych grupach pojazdów na roczną emisję CO2 ze środków transportu. W końcowej części artykułu przedstawiono wyniki wstępnych badań nad możliwością obniżania oporów tarcia w różnych węzłach tarcia występujących w pojazdach samochodowych przez wprowadzenie do olejów smarowych nanomateriałów węglowych

Intraretinal Cysts as a Manifestation of Retinal Angiomatous Proliferation in Optical Coherence Tomography Angiography

Background and Objectives: Intraretinal cysts are common pathology observed inspectral domain optical coherence tomography (SDOCT) in patients with neovascular form of age-related macular degeneration (AMD). The aim of the study was to determine if the presence of intraretinal cysts is positively correlated with diagnosis of retinal angiomatous proliferation (RAP) in optical coherence tomography angiography (OCTA). Material and Methods: A total of 21 eyes with intraretinal cysts in SDOCT exam (Group1) and 21 eyes with subretinal fluid(Group 2) were enrolled into the study. In each eye, the presence of intraretinal neovascularization (IRN) and chorioretinal anastomosis (CRA) was evaluated in OCTA by two experienced graders. Results: IRN was observed in 20 eyes (95.2%) from Group 1 and 5 eyes (23.8%) from Group 2. Features of CRA were found in 18 eyes (80.95%) and 16 eyes (76.2%) respectively for Group 1 and 2. Patients with cysts are 50 (95% CI: 5.43–460.52) times more likely to have IRN (p Conclusions: The presence of intraretinal cysts on SDOCT retinal sections in eyes with neovascular AMD corresponds to the presence of IRN on OCTA examination. The results indicate that the absence of a cyst does not exclude the presence of IRN and CRA which can be identified on OCTA

Biological activity of carbon nanoparticles produced in combustion process

In the recent years industrial applications of carbon allotropes such as carbon nanotubes (CNTs) and graphene have been tested extensively, thus justifying research on the environmental impact these materials have. In the current paper we compare EDS spectroscopy results of a cabin filter used in a car to a filter used in an air purifier inside a residential space. The contaminants adsorbed on the car-bon nanoparticles trapped in both types of filters allows for determining of their source of origin demonstrating clearly the dominant role of non-road emissions in Poland. Finally we present the experimental study on the growth of plants on substrates intentionally enriched with CNTs

Deficiency of long-chain polyunsaturated fatty acids in phenylketonuria: a cross-sectional study

The etiology of altered blood fatty acid (FA) profile in phenylketonuria (PKU) is understood only partially. We aimed to determine whether FAs deficiency is dependent on the diet or metabolic disturbances. The study comprised 40 PKU patients (20 female, 20 male; aged 11 to 35 years; 12 children and 28 adults) and 40 healthy subjects (HS; 20 female, 20 male, aged 18 to 33 years). We assessed the profile of FAs (gas chromatography/mass spectrometry) and analyzed the 72-hour dietary recalls. The amount of C14:0, C16:0 and C16:1n-7, C18:1n-9 did not differ between the analyzed groups. The percentage of C18:0 was higher, while C20:3n-9, C18:2n-6, C20:2n-6, C20:4n-6, C22:4n-6, C22:5n-6 and C22:6n-3 was lower in PKU than in HS. However, C18:3n-6, C18:3n-3 and n-6/n-3 ratio were higher in PKU patients. The C20:4n-6/C20:3n-6 ratio (reaction catalyzed by Δ5-desaturase), the C22:5n-6/C22:4n-6 and the C22:6n-3/C22:5n-3 ratio (both reactions catalyzed by Δ6 desaturase) were significantly lower in PKU patients. Therefore, the deficiency of long-chain polyunsaturated fatty acids in PKU patients may result not only from inadequate supply but also from metabolic disturbances

Reduced Quality of Life and Sexual Satisfaction in Isolated Hypogonadotropic Hypogonadism

(1) Background: Isolated hypogonadotropic hypogonadism (IHH) is a genetic condition characterized by impaired puberty and fertility. IHH can significantly impact patient health-related quality of life (HRQoL), sexual satisfaction (SS) and mood. (2) Methods: Participants included 132 IHH subjects (89 men and 43 women) and 132 sex- and age-matched controls. HRQoL, depressive symptoms, erectile dysfunction (ED), and SS were assessed in an online survey using the Zung Self-Rating Depression Scale (SDS), 15D instrument of HRQoL (15D), Sexual Satisfaction Questionnaire (SSQ), and 5-item International Index of Erectile Function (IIEF-5). (3) Results: QoL and SS were significantly lower in the IHH group vs. controls. There was a high rate of ED (53.2% vs. 33%, p = 0.008) and depressive symptoms (45.00 ± 17.00 vs. 32.00 ± 12.00, p < 0.001) in patients vs. controls. The age of patients at IHH diagnosis inversely correlated with their overall 15D scores. An alarming non-compliance rate was seen (51.6%). No differences were found between scores of patients receiving hormone replacement therapy (HRT) and untreated subjects in any of the scales. (4) Conclusions: The HRQoL, SS, ED, and depression levels observed in IHH patients, despite HRT, are alarming. Late IHH diagnosis may have a particularly negative impact on HRQoL. More attention should be devoted to HRT adherence and various HRQoL aspects of IHH patients

Anthropometric Parameters in Patients with Fatty Acid Oxidation Disorders: A Case–Control Study, Systematic Review and Meta-Analysis

This study compared the anthropometric parameters of patients with fatty acid oxidation disorders (FAOD) and healthy controls, showing an increased prevalence of abnormal body weight (overweight and obesity) in the FAOD group. First, differences in BMI, BMI percentiles and z-scores, and weight and weight percentiles were compared in a cohort of 39 patients with FAOD and 156 healthy controls, as well as between patients born before and after the introduction of a populational newborn screening programme (NBS) in 2014 in Poland. We also performed a systematic literature review yielding 12 studies mentioning anthropometric parameters in 80 FAOD patients and 121 control subjects, followed by a meta-analysis of data from 8 studies and our cohort. There were significant differences in body weight percentiles (p = 0.001), BMI (p = 0.022), BMI percentiles (p = 0.003) and BMI z-scores (p = 0.001) between FAOD patients and controls in our cohort but not between pre- and post-newborn-screening patients. The meta-analysis did not show any differences in weight and BMI in all tested subgroups, i.e., all FAOD patients vs. controls, medium-chain acyl-CoA dehydrogenase (MCADD) patients vs. controls and patients with FAOD types other than MCAD vs. controls. These results, however, should be interpreted with caution due to the overall low quality of evidence as assessed by GRADE, the small sample sizes and the significant heterogeneity of the included data

Shear Wave Elastography: A New Noninvasive Tool to Assess the Intensity of Fibrosis of Irradiated Salivary Glands in Head and Neck Cancer Patients

The aim of the study was to assess salivary gland parenchyma by means of sonoelastography in patients irradiated for head and neck squamous cell carcinoma (HNSCC). The studied group consisted of 52 patients after radiotherapy (RT) and 54 healthy volunteers. All of the former were treated for advanced larynx (40), oropharynx (9), or maxilla (3) squamous cancers and suffered from chronic dryness. Ultrasonography (US) and elastography (ES) were performed, as well as an assessment of the amount of saliva and Common Terminology Criteria for Adverse Events (CTCAE) scale. There was a statistical difference between ES values in the RT group and in the controls for parotid glands (41.7 kPa versus 26.03 kPa, P=0.0018) and for submandibular glands (37.6 kPa versus 22.4 kPa; P=0.005). There was a significant correlation between the CTCAE scores and objective saliva amount (P=0.0005), and the median amount of saliva in the examined group was lower than in the reference group (1.86 g versus 2.75 g, P=0.0006). In conclusion sonoelastography adds a new parameter to ultrasonography in “one touch examination” and may be a useful tool for major salivary gland evaluation during the radiotherapy course and follow-up period