Enhancement of Multi-Scale Self-Organization Processes during Inconel DA 718 Machining through the Optimization of TiAlCrSiN/TiAlCrN Bi-Nano-Multilayer Coating Characteristics

Optimization of the composition of a new generation of bi-nano-multilayered TiAlCrSiN/TiAlCrN-based coatings is outlined in this study for the machining of direct aged (DA) Inconel 718 alloy. Three types of TiAlCrSiN/TiAlCrN-based bi-nano-multi-layer coatings with varying chemical compositions were investigated: (1) a previous state-of-the-art Ti_0.2Al_0.55Cr_0.2Si_0.03Y_0.02N/Ti_0.25Al_0.65Cr_0.1N (coating A); (2) Ti_0.2Al_0.52Cr_0.2Si_0.08N/Ti_0.25Al_0.65Cr_0.1N with increased amount of Si (up to 8 at.%; coating B); (3) a new Ti_0.18Al_0.55Cr_0.17Si_0.05Y_0.05N/Ti_0.25Al_0.65Cr_0.1N coating (coating C) with an increased amount of both Si and Y (up to 5 at.% each). The structure of each coating was evaluated by XRD analysis. Micro-mechanical characteristics were investigated using a MicroMaterials NanoTest system and an Anton Paar-RST3 tester. The wear performance of nano-multilayered TiAlCrSiN/TiAlCrN-based coatings was evaluated during the finish turning of direct aged (DA) Inconel 718 alloy. The wear patterns were assessed using optical microscopy imaging. The tribological performance was evaluated through (a) a detailed chip characteristic study and (b) XPS studies of the worn surface of the coated cutting tool. The difference in tribological performance was found to correspond with the type and amount of tribo-films formed on the friction surface under operation. Simultaneous formation of various thermal barrier tribo-films, such as sapphire, mullite, and garnet, was observed. The overall amount of beneficial tribo-films was found to be greater in the new Ti_0.18Al_0.55Cr_0.17Si _0.05Y_0.05N/Ti_0.25Al_0.65Cr_0.1N nano-bi-multilayer coating (coating C) than in the previous state-of-the-art coatings (A and B). This resulted in over two-fold improvement of this coating’s tool life compared with those of the commercial benchmark AlTiN coating and coating B, as well as a 40% improvement of the tool life of the previous state-of-the-art coating A. Multi-scale self-organization processes were observed: nano-scale tribo-film formation on the cutting tool surface combined with micro-scale generation of strain-induced martensite zones as a result of intensive metal flow during chip formation. Both of these processes are strongly enhanced in the newly developed coating C.     

Packages of vitreous collagen (type II) in the human retina: an indication of postnatal collagen turnover?

The purpose of this study was to evaluate the vitreoretinal border in the (pre-)equatorial area in nonpathologic human donor eyes, because the majority of retinal defects induced by posterior vitreous detachment (PVD) are located there. Nine eyes (24-80 years) were fixed and embedded in Technovit 8100. After evaluation by light microscope, areas of interest were selected for immunotransmission electron microscope. Anti-type II collagen antibody was used to stain vitreous fibrils and lamellae; anti-type IV collagen antibody was used to identify the internal limiting lamina (ILL); anti-vimentin and anti-CD-68 antibodies stained retinal Muller cells and macrophages, respectively. Observations included fusing of lamellae with the ILL, an intravitreal course of the ILL, and clear focal interruptions in the ILL. In addition, an obvious finding was the presence of intraretinal packages of type II collagen. Interestingly these collagen packages were closely related to Muller cells and, in several eyes, also to macrophages, cell debris and interruptions in the ILL. In our opinion, the collagen packages can reflect the net result of a process of interactive remodelling, in which both breakdown and synthesis of vitreous and ILL collagens take place. Connections between vitreous and intraretinal collagen networks can make the (pre-)equatorial area more vulnerable to tearing and retinal detachment in the case of liquefaction and PVD.     

Furnishing spaceship environment: evaluation of bacterial biofilms on different materials used inside International Space Station

Performed inside International Space Station (ISS) from 2011 to 2016, VIABLE (eValuatIon And monitoring of microBiofiLms insidE International Space Station) ISS was a long-lasting experiment aimed at evaluating the bacterial contamination on different surface space materials subjected to different pre-treatment, to provide useful information for future space missions. In this work, surfaces samples of the VIABLE ISS experiment were analyzed to determine both the total bacterial load (ATP-metry, qPCR) and the composition of the microbial communities (16S rRNA genes amplicon sequencing).Data obtained showed a low bacterial contamination of all the surfaces, with values in agreement with those allowed inside ISS, and with a taxonomic composition similar to those found in previous studies (Enterobacteriales, Bacillales, Lactobacillales and Actinomycetales). No pre-treatment or material effect were observed on both the bacterial load and the composition of the communities, but for both a slight effect of the position (expose/not expose to air) was observed.In conclusion, under the conditions used for VIABLE ISS, no material or pre-treatment seems to be better than others in terms of quantity and type of bacterial contamination.     

原发性玻璃体后脱离致视网膜裂孔的治疗探讨

目的 分析玻璃体后脱离所致视网膜裂孔的确诊时间及不同处理对其预后的影响。方法 2000年10月至2002年8月对95例(95眼)由急性玻璃体后脱离所致视网膜裂孔眼进行临床分析。裂孔已导致视网膜脱离的行视网膜复位手术，干性视网膜裂孔行532激光封闭裂孔术。结果 59例伴有视网膜脱离的患者明确诊断时间长，经手术治疗(部分为玻璃体手术)后视功能有一定的恢复，但有些病人需多次手术。35例视网膜干性裂孔患者诊断及时，经光凝治疗后视力无明显改变。结论 玻璃体后脱离导致视网膜裂孔早期诊断，及时光凝是为患眼争取良好预后的关键。     

Bilateral above knee amputations after prolonged exposure to sorafenib and trebananib

Sorafenib is an oral tyrosine kinase inhibitor (TKI) that acts on many targets including RAF kinases, vascular endothelial growth factor (VEGF) 1, 2, 3, platelet derived growth factor and c-kit receptor and is currently FDA approved for unresectable hepatocellular carcinoma (HCC). Trebananib (AMG 386) is an angiopoietin 1/2 antagonist and acts as anti-angiogenic agent and may possess synergistic effects with sorafenib. Here we report a case of a 66-year-old male with a history of Hepatitis C, and a 22 pack year (PY) smoking history with unresectable multifocal HCC who was placed on both therapies for an extended period of time with an excellent clinical response but ended up developing bilateral critical limb ischemia requiring above knee amputations.     

Endovascular treatment of Angio‐Seal™‐related limb ischemia—Primary results and long‐term follow‐up

Objectives : To investigate primary success rates and long term follow‐up of endovascular treatment of AngioSeal?‐related limb ischemia. Background : Current knowledge on optimal therapy of ischemic complications following application of AngioSeal? is limited. Methods : A single‐center prospectively maintained database was retrospectively interrogated and AngioSeal?—related complications requiring endovascular treatment over an 8‐year‐time period was identified. Results : Fifteen patients fulfilling the inclusion criteria were identified, resulting in an approximated incidence of 0.26% of all devices implanted at our institution. In all cases, the complication was managed successfully in the absence of complications. Eleven patients were treated with balloon angioplasty (PTA) and four with stent implantation because of suboptimal PTA results. Twelve patients were available for noninvasive vascular follow‐up examination for a median time of 40 months postinterventionally. Only two patients needed a second intervention consisting of balloon angioplasty due to symptomatic restenosis. At final follow‐up all patients were asymptomatic with no relevant restenosis. Conclusion : Endovascular treatment for AngioSeal?‐related limb ischemia with or without stent implantation results in an excellent immediate and long‐term clinical and hemodynamic outcome. © 2009 Wiley‐Liss, Inc.     

Pharmacologic vitreolysis with microplasmin increases vitreous diffusion coefficients

Background Pharmacologic vitreolysis is a new approach to improve vitreo-retinal surgery and ultimately to liquefy and detach the vitreous from the retina to eliminate the contribution of the vitreous to retinopathy. The mechanism of action of the agents being developed for pharmacologic vitreolysis remains unclear. The effect of microplasmin on vitreous diffusion coefficients was investigated using the non-invasive technique of dynamic light scattering (DLS). Methods Vitreous diffusion coefficients in 18 intact porcine eyes were measured in vitro with dynamic light scattering (DLS). DLS was performed on all specimens at 37 °C 30 min after injections of human recombinant microplasmin at doses ranging from 0.125 to 0.8 mg, with 20-nm tracer nanospheres. Results DLS findings in untreated porcine vitreous were similar to the previously described findings in bovine and human vitreous. Microplasmin increased porcine vitreous diffusion coefficients in a dose-dependent manner (correlation coefficient, r=0.93), with an 85% increase after a 30-min exposure to the maximum dose. Conclusions Pharmacologic vitreolysis with human recombinant microplasmin increases vitreous diffusion coefficients in vitro. The results of these studies have implications for the dosing, route of administration, duration of action and methods of determining efficacy in future studies of pharmacologic vitreolysis to enhance vitreo-retinal surgery, as well as the design of clinical trials to induce prophylactic posterior vitreous detachment. This work is an abridgement of a thesis submitted in partial fulfillment of requirements for membership in the American Ophthalmological Society, May 2005.