Stainless steel, CoCrMo alloy and titanium alloy are the most commonly used metal materials for artificial joint. But the generation of wear debris and metal ions limits the use of the metal, ...especially for the metal-on-metal type artificial joint. Diamond like carbon (DLC) coating can reduce the wear and corrosion of these metal alloys. But the service behavior of the DLC coating on different metal substrates may be different. This paper studied the difference of the structure, adhesion, wear and corrosion properties of the DLC coating on different substrates (stainless steel, CoCrMo or titanium alloy). The results show that the structure of the DLC coating on these substrates is similar. The DLC coating on titanium alloy shows the best adhesion than that on stainless steel and CoCrMo alloy, because the chemical bond energy holding Ti atom (of titanium alloy surface) and C atom (of DLC) together is the strongest. The failure mode of DLC coatings on 316L stainless steel and CoCrMo alloy in the friction test is coating delamination. The DLC coating on Ti6Al4V alloy shows the best wear resistance due to its good adhesion. Immersion and electrochemical tests show that the DLC coating on Ti6Al4V substrate has better stability than that on 316L stainless steel and CoCrMo alloy because the Ti6Al4V substrate can prevent the corrosion more efficiently than 316L stainless steel and CoCrMo alloy. In the case of no interlayer, Ti6Al4V alloy is the most feasible metal joint material for DLC modification with good adhesion, wear and corrosion resistance compared with 316L stainless steel and CoCrMo alloy.
•The structure of DLC coatings on 316L SS, CoCrMo and Ti6Al4V is similar.•The DLC on Ti6Al4V has the best adhesion compared with the ones on 316L SS and CoCrMo.•The failure mode of DLC coating on 316L SS and CoCrMo in PBS is coating spallation.•The DLC/Ti6Al4V has better stability than the ones on 316L SS and CoCrMo in PBS.
In this paper, we report a 3.7 kW all fiber narrow linewidth single mode fiber laser. The full width at half-maximum is about 0.30 nm, and the beam quality is Mx2=1.358, My2=1.202 at maximum output ...power. The laser is achieved by simultaneously suppressing nonlinear effects and mode instability (MI). Different seeds are injected into the main amplifier to study stimulated Raman scattering (SRS) effect. The results show that the phase modulated single frequency seed is benefit to suppress the SRS effect. For the phase modulated single frequency seed, inserting a filter in preamplifier will suppress amplified spontaneous emission (ASE) and decrease the backward power. By optimizing the coiling of active fiber, the MI effect is suppressed.
Bimetallic NiCu catalysts supported on mesoporous SiO
2
nanorods were prepared by impregnation method with the help of complexing agents. The introduction of various complexing agents including ...citric acid (CA), polyvinyl pyrrolidone (PVP), triethanolamine (TEOA), triethylamine (TEA) and ammonia (AMH) significantly affected the metal particle size, surface chemical state, redox and acidic properties. The NiCu/SiO
2
–PVP catalyst had the smallest metal nanoparticle sizes of 2.3 nm among the catalysts. The variation of metal particle size resulted in the differences of the metal-support interaction, which further caused the changes of the redox property. Acidic property was another indispensable factor to promote this reaction, and the types of complexing agents did not change the acidic strength distribution but the total number of that. The apparent activation energy on NiCu/SiO
2
–PVP was 26.55 kJ/mol, which was obviously lower than that on NiCu/SiO
2
–AMH (37.49 kJ/mol). Consequently, the NiCu/SiO
2
–PVP catalyst exhibited the best activity compared to other catalysts in the gas phase catalytic hydrogenation of levulinic acid with formic acid as the hydrogen source, achieving the highest levulinic acid conversion of 76.9% and γ-valerolactone selectivity of 91.6%. It also showed good catalytic stability within 20 h time-on-stream.
For physical surface modification of a complex workpiece, the incoming particles are difficult to arrive at the inclined surface of the complex workpiece due to self-shadowing effect. This will ...result in the non-uniformity distribution of structure and properties of the films on different surfaces of the complex workpiece. In order to mitigate the self-shadowing effect and improve the uniformities of film structure and properties, high power pulsed magnetron sputtering (HPPMS) was used to fabricate TiN films on 316L stainless steel substrate with different inclination angles. During deposition, the electrical characteristic of HPPMS was recorded by an oscilloscope, and the plasma component was diagnosed by optical emission spectroscopy. The structure, mechanical and corrosion properties of the TiN films deposited on substrate with different inclination angles by DC magnetron sputtering (DCMS) and HPPMS also were studied respectively. Compared with DCMS, the results showed that high ion/atom ratio and large ion flux in HPPMS led to stronger ion bombardment and adatom mobility, which caused densification of the TiN films. The uniformities of hardness and corrosion resistance of the TiN films deposited on the substrate with different inclination angles were improved by HPPMS. And for HPPMS, the longer pulses at same duty cycle could efficiently mitigate the self-shadowing effect and improve the hardness and corrosion resistance of the TiN-coated stainless steel.
•The TiN films deposited at different inclination angles by DCMS show bad uniformity.•The uniformities of film hardness and corrosion resistance can be improved by HPPMS.•The longer pulses are helpful to mitigate the self-shadowing effect at same duty cycle for HPPMS.
Tobacco smoking and dermatologic surgery Gill, Jing F., MD; Yu, Siegrid S., MD; Neuhaus, Isaac M., MD
Journal of the American Academy of Dermatology,
01/2013, Letnik:
68, Številka:
1
Journal Article
Recenzirano
Background Cigarette smoking is the leading cause of preventable death and a major public health concern. Numerous clinical and experimental studies have examined the effect of nicotine on wound ...healing and surgical procedures, but there are limited published reports in the dermatologic surgery literature. Objective This article seeks to develop evidence-based recommendations regarding the effect of tobacco use in patients undergoing dermatologic surgery procedures. Methods This article reviews the existing published English-language literature pertaining to the effects of tobacco on wound healing and surgical complications. Results Tobacco use is associated with a higher incidence of postoperative complications including wound dehiscence, flap or graft necrosis, prolonged healing time, and infections. Limitations This review article only summarizes past reports and studies. Conclusion Recommendations for smoking cessation before dermatologic surgery are provided based on the available data.
TiN film has been used in the surface modification of orthopaedic implants due to its favorable biocompatibility and tribological properties. Copper ions have low toxicity and biological functions. ...In this study, copper was doped to TiN film to enhance the viability of osteoblast and decrease the inflammatory response of macrophages for TiCuN film applications in orthopaedic implants. TiCuN films with different Cu contents were deposited on Si wafers by direct current (DC) magnetron sputtering technique. The effects of Cu content on the TiCuN film structure, surface morphology, and surface energy were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and contact angle measurements. The results demonstrated that Cu doping could suppress the columnar structure of TiN films, change the surface of the TiN film from hydrophilic to hydrophobic, and reduce its surface energy. When the Cu content reached 11.1 at.%, Cu nanocrystals were formed in the TiCuN film. The biocompatibility of the TiCuN films with different Cu contents was analyzed based on osteoblasts and macrophages. The results demonstrated that the viability and morphology of osteoblasts on the TiCuN films with a Cu content of 2.4 at.% were significantly improved compared with those of the CoCrMo alloy and TiN film. The inflammatory response induced by the TiCuN films with Cu contents of 2.4 and 4.2 at.% was lower than that induced by the CoCrMo alloy and TiN film without Cu doping. The TiCuN film with optimum Cu content of 2.4 at.% promoted the viability of osteoblasts and reduced the inflammatory response of macrophages.
•As Cu content increases, columnar structure of the TiN film gradually transforms into a dense and featureless structure.•When the Cu content reaches 11.1 at.%, Cu nanocrystals are formed in the TiCuN film.•TiCuN film with a Cu content of 2.4 at.% promoted osteoblast viability and reduced the macrophage inflammatory response.
With arterial hypertension as a global risk factor for cerebrovascular and cardiovascular diseases, we examined whether retinal blood vessel caliber and tortuosity assessed by a vessel-constraint ...network model can predict the incidence of hypertension.
The community-based prospective study included 9230 individuals who were followed for 5 years. Ocular fundus photographs taken at baseline were analyzed by a vessel-constraint network model.
Within the 5-year follow-up, 1279 (18.8%) and 474 (7.0%) participants out of 6813 individuals free of hypertension at baseline developed hypertension and severe hypertension, respectively. In multivariable analysis, a higher incidence of hypertension was related to a narrower retinal arteriolar diameter ( P < 0.001), wider venular diameter ( P = 0.005), and a smaller arteriole-to-venule diameter ratio ( P < 0.001) at baseline. Individuals with the 5% narrowest arteriole or the 5% widest venule diameter had a 17.1-fold 95% confidence interval (CI):7.9, 37.2 or 2.3-fold (95% CI: 1.4, 3.7) increased risk for developing hypertension, as compared with those with the 5% widest arteriole or the 5% narrowest venule. The area under the receiver operator characteristic curve for predicting the 5-year incidence of hypertension and severe hypertension was 0.791 (95% CI: 0.778, 0.804) and 0.839 (95% CI: 0.821, 0.856), respectively. Although the venular tortuosity was positively associated with the presence of hypertension at baseline ( P = 0.01), neither arteriolar tortuosity nor venular tortuosity was associated with incident hypertension (both P ≥ 0.10).
Narrower retinal arterioles and wider venules indicate an increased risk for incident hypertension within 5 years, while tortuous retinal venules are associated with the presence rather than the incidence of hypertension. The automatic assessment of retinal vessel features performed well in identifying individuals at risk of developing hypertension.
An image retrieval framework that integrates efficient region-based representation in terms of storage and complexity and effective on-line learning capability is proposed. The framework consists of ...methods for region-based image representation and comparison, indexing using modified inverted files, relevance feedback, and learning region weighting. By exploiting a vector quantization method, both compact and sparse (vector) region-based image representations are achieved. Using the compact representation, an indexing scheme similar to the inverted file technology and an image similarity measure based on Earth Mover's Distance are presented. Moreover, the vector representation facilitates a weighted query point movement algorithm and the compact representation enables a classification-based algorithm for relevance feedback. Based on users' feedback information, a region weighting strategy is also introduced to optimally weight the regions and enable the system to self-improve. Experimental results on a database of 10 000 general-purposed images demonstrate the efficiency and effectiveness of the proposed framework.
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