Quantitative assessment of mobile protein levels in human knee synovial fluid: feasibility of chemical exchange saturation transfer (proteinCEST) MRI of osteoarthritis

Purpose

To establish the feasibility of chemical exchange saturation transfer (proteinCEST) MRI in the differentiation of osteoarthritis (OA) knee joints from non-OA joints by detecting mobile protein and peptide levels in synovial fluid by determining their relative distribution.

Materials and Methods

A total of 25 knees in 11 men and 12 women with knee injuries were imaged using whole knee joint proteinCEST MRI sequence at 3 T. The joint synovial fluid was segmented and the asymmetric magnetization transfer ratio at 3.5 ppm MTR_asym (3.5 ppm) was calculated to assess protein content in the synovial fluid. The 85th percentile of synovial fluid MTR_asym (3.5 ppm) distribution profile was compared using the independent Student's t test. The diagnostic performance of the 85th percentile of synovial fluid MTR_asym (3.5 ppm) in differentiating OA and non-OA knee joints was evaluated.

Results

The 85th percentile of synovial fluid MTR_asym (3.5 ppm) in knee joints with OA was 8.6%±3.4% and significantly higher than that in the knee joints without OA (6.3%±1.4%, P<.05). A knee joint with an 85th percentile of synovial fluid MTR_asym (3.5 ppm) greater than 7.7% was considered to be an OA knee joint. With the threshold, the sensitivity, specificity and overall accuracy for differentiating knee joints with OA from the joints without OA were 54% (7/13), 92% (11/12) and 72% (18/25), respectively.

Conclusion

proteinCEST MRI appears feasible as a quantitative methodology to determine mobile protein levels in synovial fluid and identify patterns characteristic for OA disease.     

Influence of temperature on structure as well as adhesion and friction and wear behavior of hydrogenated carbon nitride films prepared on silicon substrate

Hydrogenated-carbon nitride (CN_x:H) films were synthesized on silicon substrate in a large quantity by the pyrolysis of ethylenediamine in a temperature range of 700-950 °C. The influence of temperature on the morphology, structure, adhesion to substrate, and friction and wear behavior of CN_x:H films was investigated. It has been found that CN_x:H films obtained at 700 °C and 800 °C are amorphous, and those prepared at 900 °C and 950 °C consist of carbon nitride nanocrystal. Besides, CN_x:H film sample obtained at 700 °C has the maximum N content of 9.1 at.% but the poorest adhesion to Si substrate, while the one prepared at 900 °C has the lower N content and the highest adhesion to substrate. As a result, nanocrystalline CN_x:H (nc-CN_x:H) film synthesized at 900 °C possesses the best wear resistance when slides against stainless steel counterpart. N atom is incorporated into the graphitic network in three different bonding forms, and their relative content is closely related to temperature, corresponding to different adhesion as well as friction and wear behavior of the films obtained at different temperatures. Furthermore, the friction coefficient and antiwear life of as-deposited CN_x:H films vary with varying deposition temperature and thickness, and the film with thickness of 1.3 μm, obtained at 900 °C, has the longest antiwear life of over 180,000 s.     

Effects of thermo-hygro-mechanical densification on the surface characteristics of trembling aspen and hybrid poplar wood veneers

The effect of thermo-hygro-mechanical (THM) densification temperature on the surface color, roughness, wettability, and chemical composition of trembling aspen (Populus tremuloides) and hybrid poplar (Populus maximowiczii × P. balsamifera) veneers was investigated. Veneers were subjected to four THM densification temperatures (160 °C, 180 °C, 200 °C, and 220 °C). Veneer color darkened with increasing THM densification temperature. Surface roughness decreased between 160 °C and 200 °C. Wettability decreased after THM densification, but no significant difference was found between treated specimens. ATR-FTIR and XPS results confirmed that THM densification caused major chemical changes in veneer surfaces, and more pronounced at temperatures higher than 160 °C.     

In situ growth stresses during the phase separation of immiscible FeCu thin films

This paper addresses the in situ growth stress evolution and post-growth stress relaxation during the phase separation of immiscible Fe_0.51Cu_0.49 thin films at various in situ deposition temperatures. Each film was sputter-deposited onto a 10 nm Si₃N₄ underlayer that was grown on top of Si [0 0 1] substrate at 25 °C, 145 °C, 205 °C, 265 °C or 325 °C. The thin film stress was measured using a wafer curvature technique. The in situ growth stress increased in compression with increasing substrate temperature. The stress relaxation of the Fe_0.51Cu_0.49 was found to have a linear increase with the inverse grain size for films deposited at temperatures greater than 205 °C. The stress state was correlated to the films’ phase and morphology by X-ray diffraction, (scanning) transmission electron microscopy and atomic force microscopy techniques.     

Influence of the substrate position angle on the adhesion of ZnO thin films deposited on polyimide foil substrates

ZnO thin films, as polymer protection layers against ultraviolet radiation, were deposited on polyimide foil substrates using cathodic vacuum arc deposition technique. X-ray diffraction results showed that all the samples had (0 0 2) preferred orientation and the FWHM decreased as the position angle decreased. A fragmentation test was employed to investigate the influence of substrate position angle on the adhesion of ZnO thin films. It was found that the intrinsic adhesion between the ZnO film and the polyimide substrate is about 60 MPa at the substrate position angle of 0°. When the position angle increases to ±60°, the value of intrinsic adhesion decreases to about 30 MPa.     

AFM investigation on surface evolution of amorphous carbon during ion-beam-assisted deposition

Hydrogen-free amorphous carbons (a-C) have been prepared on mirror-polished Si(1 1 1) wafers through thermally evaporated C₆₀ with simultaneous bombardments of Ne⁺ ions. The time evolution of film surfaces has been characterized by atomic force microscopy (AFM) at two temperatures of 400 and 700 °C, respectively. Based on the topography images and the root-mean-square (rms) roughness analysis, it is found that the a-C surfaces present roughening growth at the initial stage. With increasing growth time, the cooperative nucleation of the islands and pits appears on the surfaces, suggesting three-dimensional growth, and then they continue to evolve to irregular mounds at 400 °C, and elongated mounds at 700 °C. At the steady growth stage, these surfaces further develop to the structures of bamboo joints and ripples corresponding to these two temperatures, respectively. It is believed that besides ion sputtering effect, the chemical bonding configurations in the amorphous carbon films should be taken into considerations for elucidating the surface evolutions.     

Ultrasound assisted oxidative desulfurization of model diesel fuel

Very stringent environmental regulations have limited the level of sulfur in diesel, therefore deep desulfurization of fuels is required. For that purpose, the frequently used industrial process is hydrodesulfurization (HDS) which enables effective elimination of sulfur compounds such as mercaptanes, thiols, sulfides, disulfides from diesel oil, but removal of thiophene sulfur compounds (benzothiophene, dibenzothiophene, 4,6 dimethyldibenzothiophene) is insufficient. Ultrasound assisted oxidative desulfurization (UAOD) as one of several new technologies enables performance under mild conditions without use of explosive hydrogen. A higher reactivity of thiophene sulfur compounds during UAOD also provides conversion into highly polar sulfoxides and sulfones that are easily removed by adsorption or extraction. Nowadays, different catalyst/oxidants systems are being studied to improve oxidation reaction efficiency and enhance the mass transfer in the interfacial region. In this paper, the effect of reaction temperature (40–70 °C) and oxidation time (5–150 min) for UAOD of model diesel fuel with a catalyst/oxidants system (acetic acid/hydrogen peroxide) was investigated in a 70 ml batch reactor. Furthermore, the effects of different initial concentrations of dibenzothiophene (DBT) and of ultrasound amplitude were additionally examined to achieve efficient sulfur removal. The obtained results indicated that temperature and US amplitude of 70 °C and 80% respectively were efficient for conversion of DBT (sulfur concentration up to 3976.86 ppm). The results indicate a rise in the yield of sulfones at higher temperatures and subsequent extraction with N,N-dimethylformamide conducted after the process of oxidation at different solvent/oil ratio revealed sulfur removal efficiency of 98.35%.     

Trace element changes during hibernation of Drosophila melanogaster by WDXRF analyses at chilling temperature

Fruit flies (Drosophila melanogaster) were exposed to low temperature (4 °C, 3d), after controlled acclimation (15 °C, 1d) and passed to artificial hibernation. The concentrations of elements in almost 1000 mature flies were measured by Wavelength-Dispersive X-ray Fluorescence (WDXRF) spectrometry. Concentration changes of Zn, K, S, Ca (33.5%, 11.2%, 10.3% and 7.5%, respectively) and especially Cr and Mn (99.90 and 99.60) were observed. Concentrations of Cr, Zn, S and Ca increased significantly, but concentrations of Mn and K decreased in with comparison to the control group.     

Effect of annealing temperature on microstructure, hardness and adhesion properties of TiSixNy superhard coatings

A series of TiSi_xN_y superhard coatings with different Si contents were prepared on M42 steel substrates using two Ti and two Si targets by reactive magnetron sputtering at 500 °C. These samples were subsequently vacuum-annealed at 500, 600, 700, 800 and 900 °C, respectively. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), microindenter, Rockwell hardness tester and scratch tester were applied to investigate the microstructure, phase configuration, hardness and adhesion properties of as-deposited and annealed samples. The results indicated that there were two bonds, TiN and Si₃N₄, in all presently deposited TiSi_xN_y thin films, that structure was nanocomposite of nanocrystalline (nc-) TiN embedded into amorphous Si₃N₄ matrices. Annealing treatment below 900 °C played a little role in microstructure and hardness of the coatings although it greatly affected those of steel substrates. The film-substrate adhesion strength was slightly increased, followed by an abrupt decrease with increasing annealing temperature. Its value got to the maximum at 600 °C. Annealing had little effect on the friction coefficient with its value varying in the range of 0.39-0.40.     

Manganese-enhanced magnetic resonance imaging investigation of the interferon-α model of depression in rats

Therapeutic effects of interferon-α (IFN-α) are known to be associated with CNS toxicity in humans, and in particular with depression symptoms. Animal models of IFN-α-induced depression (sickness behaviour) have been developed in rodents using various preparations, dosing schedules or routes of administrations. In this work, Manganese Enhanced MRI (MEMRI) has been applied to investigate an experimental model of sickness behaviour induced by administration of IFN-α in rats. IFN-α (3.10⁵ U/kg), or vehicle, was daily administered i.p., for 7 days in rats (n = 20 IFN-α treated and n = 20 controls). After treatment, animals were assigned to behavioural (n = 10 treated, n = 10 control) or MRI (n = 10 treated and n = 10 control) studies. Animals assigned to the MRI study received two repeated i.p. injections of MnCl₂, before image acquisition. Images were acquired at 4.7 T using T₁ mapping for determination of Mn concentration in brain. After co-registration of T₁ maps to a digital brain atlas, differences between brains of treated and untreated animals were assessed pixel-to-pixel by statistical analysis.