Defining Dry Eye from a Clinical Perspective

Over the past decades, the number of patients with dry eye disease (DED) has increased dramatically. The incidence of DED is higher in Asia than in Europe and North America, suggesting the involvement of cultural or racial factors in DED etiology. Although many definitions of DED have been used, discrepancies exist between the various definitions of dry eye disease (DED) used across the globe. This article presents a clinical consensus on the definition of DED, as formulated in four meetings with global DED experts. The proposed new definition is as follows: “Dry eye is a multifactorial disease characterized by a persistently unstable and/or deficient tear film (TF) causing discomfort and/or visual impairment, accompanied by variable degrees of ocular surface epitheliopathy, inflammation and neurosensory abnormalities.” The key criteria for the diagnosis of DED are unstable TF, inflammation, ocular discomfort and visual impairment. This definition also recommends the assessment of ocular surface epitheliopathy and neurosensory abnormalities in each patient with suspected DED. It is easily applicable in clinical practice and should help practitioners diagnose DED consistently. This consensus definition of DED should also help to guide research and clinical trials that, to date, have been hampered by the lack of an established surrogate endpoint.     

Molding of reprocessed thermoplastics with preplastication injection molding

The injection molding of reprocessed plastics with a preplastication plunger injection‐molding machine was investigated with a focus on the processing conditions. The process of the filling of the resin into the mold is much better controlled with preplastication than with processing in a conventional injection‐molding machine. Reprocessing of the resin leads to a reduction in molecular weight due to drastic changes in the resin morphology, thereby causing a reduction in melt viscosity. Direct experimental evidence for reduced viscosity was obtained from measurements of the filling pressure recorded on the machine and also with a melt‐flow indexer. The results of this study provide a practical solution for reducing the resin temperature when reprocessed resin is used in the injection molding of plastics. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1455–1461, 2001     

Structure and properties of poly(vinyl alcohol)/κ‐carrageenan blends

Blends of a commercial atactic poly(vinyl alcohol) (a‐PVA) derived from vinyl acetate and κ‐carrageenan were prepared by mixing the aqueous solutions of both samples. Blend films prepared by casting were transparent. In the DSC curves of the blend films, the endothermic peaks shifted to lower temperature with an increase of the content of κ‐carrageenan. The Young's modulus and the strength at break increased with an increase of the content of a‐PVA. As the standing temperature of the blend solutions decreased, the gelation region increased also at high content of carrageenan. In the amorphous regions of blend films, a‐PVA and κ‐carrageenan were miscible. © 2001 Society of Chemical Industry     

Preparation of Mn2+-Cu+ co-doped P2O5–ZnO–Al2O3 glasses and their red fluorescence properties

To make a Mn²⁺-doped red glass phosphor that can be excited with ultraviolet (UV) light of light-emitting diodes (LEDs), 60P₂O₅-35ZnO-5Al₂O₃-8MnO-xCu₂O glasses (x = 0-1.00) were prepared by a melt-quenching method at 1200-1400°C for 30-180 minutes in atmospheric air, and the redox of Mn and Cu as well as fluorescence properties were investigated. The Mn²⁺ ion was not reduced and oxidized in the melting, quenching, and annealing processes. The valence of Cu in the glasses changed in the order of 0, 1+, and 2+ with the increase in the amount of Cu₂O and in the melting temperature and time. In this study, a 60P₂O₅-35ZnO-5Al₂O₃-8MnO-0.10Cu₂O glass melted at 1250°C for 90 minutes, having the highest Cu⁺ concentration, showed the strongest Mn²⁺ red fluorescence under the UV light at 275 nm. This strong Mn²⁺ red fluorescence has been caused by the energy transfer from excited Cu⁺ ions to Mn²⁺ ions.     

Machine tool component error extraction and error compensation by incorporating statistical analysis

The extraction of component errors of a machine tool’s axes is a critical step for the synthesis of 3D volumetric error mapping, which is a prerequisite to improve the machine tool accuracy by numerical error compensation. This paper presents a method for the extraction of machine tool component errors from a statistical point of view. First, the B-Spline mathematical model is established to represent the component error function, and the least-squares fitting method to measured data points is presented. Then, statistical analysis is used to select the B-Spline model with proper flexibility, so as to separate repeatable errors from random errors in the measured data. Finally, based on the component error extraction method, numerical error compensation experiments were conducted on the XY-plane of a high precision machine tool by using a cross-grid scale system. According to the statistical analysis of the experimental data, all repeatable errors except the dynamic errors caused by machine tool control system were compensated for.     

Oxidation Resistance Evaluation of Silicon Carbide Ceramics with Various Additives

Five silicon carbide ceramics with various additives were evaluated for oxidation resistance at 1300°C in flowing dry and wet air. In the dry atmosphere, the oxidation of the five samples was diffusion-controlled, and in wet atmosphere they exhibited a linear relation beween weight gain by oxidation and water vapor content. Water vapor in the atmosphere strongly accelerated oxidation. The influence of oxidation on room-temperature strength was complex, but the samples were not as affected by oxidation.     

Synthesis of High-Purity Zirconium Fluoride for Fluoride Glass Fibers by Chemical Vapor Deposition

A technique for synthesizing ultra-high-purity ZrF₄ using chemical vapor deposition in a ZrBr₄–HF system is developed and a purification mechanism is clarified. The Fe concentration in ZrF₄ is evaluated at less than 10 ppb based on analysis of the transmission loss spectrum of a fiber prepared using synthesized ZrF₄. Purification is achieved mainly in a sublimation process of ZrBr₄, and purification efficiency is determined by sublimation temperature and activity of impurities in ZrBr₄. The concentration of transition-metal impurities in ZrF₄, synthesized by chemical vapor deposition in the ZrBr₄–HF system, is expected to be less than 1 ppb.     

Spherical-Impact Damage and Strength Degradation in Silicon Nitrides for Automobile Turbocharger Rotors

Spherical-impact damage to two silicon nitrides is investigated. Gas-pressure-sintered silicon nitride exhibits an elastic response to impact by spherical partially stabilized zirconia particles, resulting in Hertzian cone-crack initiation in the sintered body. Pressureless-sintered silicon nitride, on the other hand, demonstrated an elastic/plastic response, with median/radical-crack initiation. These differences in behavior are due to their microstructural differences as well as to the different hardness values of the silicon nitrides in relation to those of the PSZ spheres. The postimpact bend strength of silicon nitrides is also degraded when crack length exceeds the inherent flaw size.     

Sintering of the Mechanochemically Activated Powders of Hexagonal Boron Nitride

Pressureless sintering of hexagonal boron nitride (BN) was performed using a powder activated by mechano-chemical treatments. Physical properties of the sintered BN bodies depend on the type of starting powder and the conditions of the treatments. The BN body, which was obtained at 2000°C using an appropriate activated powder, was 99 wt% pure and was excellent in mechanical and physical properties, in spite of its low density (1.64 g/cm³).