No abstract

X-ray absorption near-edge structure (XANES) spectroscopy has been used to characterize the chemistry of antiwear (AW) films generated from mineral base oil containing a zinc dialkyl dithiophosphate additive. These films were formed on rubbed steel surfaces with a reciprocating boundary contact using different sliding frequencies. The phosphorus L-edge XANES spectra show that these films have slightly different chemical natures. Longer chain polyphosphates were present on the steel surface prepared at the higher sliding frequencies. The surface morphology of these films was investigated using atomic force microscopy. These images show that the surface morphology of the AW films changes with the sliding frequency. Round and bigger antiwear pads were formed at a lower frequency while higher frequencies resulted in thinner films and flattened surfaces. Nanomechanical properties of these antiwear films were investigated by nanoindentation measurement and the elastic moduli extracted from force-displacement (f-d) curves are similar for all antiwear films, 100 ± 10 GPa.

X-ray absorption near edge structure (XANES) spectroscopy has been used to characterize the chemistry of thermal films on steel samples, which were generated from a mineral base oil containing a zinc dialkyl dithiophosphate (ZDDP) additive. These films were formed at 150°C by immersing steel coupons in ZDDP oil solutions. The phosphorus L-edge XANES spectra show that these films are composed of polyphosphates, unreacted ZDDP and other thiophosphate intermediates. Phosphorus K-edge FY XANES was used to monitor the thickness of these films, and the data are consistent with thickness derived by focussed ion beam (FIB) milling and SEM imaging. The sulphur K-edge TEY and FY XANES spectra show that these films are composed of different sulphur components, which depend upon the formation times. The surface morphology of these films was investigated using atomic force microscopy (AFM). These images show that the surface morphology of the thermal films changes with the formation time. 31P NMR spectra show that both primary and secondary ZDDP decomposes gradually at 150°C.

Antiwear (AW) films, generated from a mineral base oil containing a zinc dialkyl dithiophosphate (ZDDP) additive, were studied as a function of formation temperature, load and rubbing time. The surface morphology of these films was investigated using atomic force microscopy (AFM), and surface roughness calculated for the observed differing surface morphologies. The morphology of the films is heterogeneous for all the tested conditions, but the surface roughness is dependent on the rubbing condition. X-ray absorption near edge structure (XANES) spectroscopy has been used to characterize the chemistry of these films, and the intensity of the phosphorus K-edge was also used to monitor their thickness. The thickness of these films is in the range of 10-90 nm depending on the running conditions. Phosphorus L-edge spectra show that these films have a similar chemical nature with variable polyphosphate chain-lengths. 31P NMR was used to study the decomposition of ZDDP in the residual oils. The spectra show that the primary and secondary ZDDP react differently under the various conditions. The tribological characteristics of these AW films were probed by measuring the coefficients of friction (l) and the wear scar width (WSW) of the counter faces. l is highly related to the applied load and the results of WSW measurements show that the wear performance is related to all the tested parameters, temperature, load and rubbing time.

We conducted a meta-analysis to evaluate the relationship between erythropoietin (EPO) polymorphisms and diabetic microvascular complications. We searched the PubMed, Embase, Cochrane library, Web of Science, Wanfang, and Chinese National Knowledge Infrastructure databases for appropriate studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the associations. Ultimately, eight studies consisting of 2,861 cases and 2,136 controls were identified and included in our meta-analysis. Results with our genotype model indicated an association between rs1617640 polymorphisms and diabetic microvascular complications (TT vs. GG: OR = 1.544, 95% CI = 1.089–2.189, P = 0.015). No clear associations between the rs1617640 and rs507392 polymorphisms and diabetic retinopathy were observed. By contrast, rs551238 polymorphisms were associated with increased diabetic retinopathy risk (allele model: OR = 0.774, 95% CI = 0.658–0.911, P = 0.002; genotype model: AC vs. CC: OR = 0.598, 95% CI = 0.402–0.890, P = 0.011; dominant model: OR = 0.561, 95% CI = 0.385–0.817, P = 0.003; recessive model: OR = 0.791, 95% CI = 0.643–0.973, P = 0.026). These results indicate that EPO polymorphisms are a risk factor for diabetic microvascular complications.

To explore the effects of atorvastatin on hydrocephalus, neurocyte apoptosis, and the level of plasma matrix metalloproteinase-9 (MMP-9) after intracerebral hemorrhage (ICH) in rats. A rat model of ICH was established by intracerebral injection of collagenase. The brain water content was determined by the wet/dry weight ratio, ultrastructural changes in brain tissue were observed by electron microscopy, and the level of plasma MMP-9 was quantified by ELISA. Atorvastatin showed significant effects in reducing the brain water content, blocking neuron apoptosis, and decreasing plasma MMP-9 in rats with ICH. There was a positive linear correlation between plasma MMP-9 and the brain water content. Atorvastatin can significantly relieve brain edema, decrease the brain injury caused by MMP-9 and protect neurons in rats with ICH.

Aim To analyse the patient safety competency (PSC) of Chinese nurses with associate degrees (ADNs) and explore factors. Design A cross‐sectional study. Methods A convenience sample of 451 ADNs working in 18 hospitals located in Chongqing city of China was investigated using the Patient Safety Competency Nurse Evaluation Scale (PSCNES). Descriptive and inferential statistics were used to analyse the data. Results ADNs had a moderate level of PSC. In terms of the six dimensions of PSC, ADNs performed well in clinical practice and safety risk management, while they performed poorly in patient‐centred care and patient safety culture. Statistically significant differences were reported in two items. Firstly, ADNs who have participated in patient safety training had a higher level in all dimensions of PSC than those who have not participated in related training. Secondly, ADNs without professional titles had a higher level of patient safety culture than those with professional titles.

X-ray absorption near-edge structure (XANES) analysis has been used to characterize the chemistry of antiwear films formed in a mineral base oil containing a zinc dialkyl dithiophosphate (ZDDP) additive. These films were formed by rubbing the AISI 1095 steel samples under a reciprocating boundary contact. The steel samples were tempered to produce different Vickers hardness values. The phosphorus L-edge XANES spectra show that these films differ slightly in their chemical nature, with longer chain polyphosphates being formed on samples with higher hardness value. The surface morphology of the films was investigated using Atomic force microscopy (AFM) and the film thickness was probed by Focussed ion beam and Scanning electron microscopy (FIB/SEM) techniques. Furthermore, the nanomechanical properties of these antiwear films were investigated by nanoindentation methods. Tribological measurements of the coefficient of friction (l) and wear scar width (WSW) indicate that the poorest antiwear film was formed on the softest substrate, which exhibited the largest WSW and the highest average l. FIB/ SEM images show that the thicknesses of the antiwear pads and the degree of damage on the substrates both change with the hardness value of the samples.