Influence of pars plana vitrectomy on ocular surface using noninvasive Keratograph 5M

AIM: To evaluate the influence of pars plana vitrectomy (PPV) on ocular surface using Keratograph 5M. METHODS: Totally 30 consecutive patients (30 eyes) undergoing primary 23-gauge PPV were recruited in the study. Ocular Surface Disease Index (OSDI) questionnaire was performed. Ocular surface parameters, including tear meniscus height (TMH), noninvasive tear break up time (NITBUT) and bulbar redness score were obtained preoperatively, in 1, 2, 4, 8 and 12wk postoperatively by Keratograph 5M. Correlations between all the clinical parameters were analyzed further. RESULTS: The percentages of both photophobia and gritty within 4wk after PPV were significantly higher than pre-operation, while they decreased to the preoperative levels in both 8wk and 12wk postoperatively. The percentage of sore eyes in the first week postoperatively was significantly higher than pre-operation, but there were no significant differences between the percentages of pre-operation and 2, 4, 8, and 12wk postoperatively. OSDI score increased significantly within 4wk postoperatively, but it returned to the preoperative level in 8 and 12wk. TMH increased with 2wk postoperatively, but there were no significant differences compared with preoperation. Both NITBUT-first and NITBUT-average shortened significantly within 8 weeks postoperatively, but they gradually improved to the preoperative levels in 12wk. Bulbar redness score was significantly higher than the preoperative level within 4wk postoperatively, but it returned to the preoperative level in 8wk. NITBUT-first and NITBUT-average had a significant positive correlation at each visit. TMH had a significant positive correlation with NITBUT-average in the first week postoperatively. CONCLUSION: Keratograph 5M can provide a reliable noninvasive method to assess the influence of PPV on the ocular surface. PPV may cause various changes in both symptoms and signs of ocular surface damages at the early stage, while all these changes will return to preoperative levels gradually in 12wk postoperatively.

Study on Improving the Precise Machinability of Single Crystal SiC by an Ultrasonic-Assisted Hybrid Process

Silicon carbide (SiC) devices have become one of the key research directions in the field of power electronics. However, due to the limitation of the SiC wafer growth process and processing capacity, SiC devices, such as SiC MOSFET (Metal-oxide-semiconductor Field-effect Transistor), are facing the problems of high cost and unsatisfied performance. To improve the precise machinability of single-crystal SiC wafer, this paper proposed a new hybrid process. Firstly, we developed an ultrasonic vibration-assisted device, by which ultrasonic-assisted lapping and ultrasonic-assisted CMP (chemical mechanical polishing) for SiC wafer were fulfilled. Secondly, a novel three-step ultrasonic-assisted precise machining route was proposed. In the first step, ultrasonic lapping using a cast iron disc was conducted, which quickly removed large surface damages with a high MRR (material removal rate) of 10.93 μm/min. In the second step, ultrasonic lapping using a copper disc was conducted, which reduced the residual surface defects with a high MRR of 6.11 μm/min. In the third step, ultrasonic CMP using a polyurethane pad was conducted, which achieved a smooth and less damaged surface with an MRR of 1.44 μm/h. These results suggest that the ultrasonic-assisted hybrid process can improve the precise machinability of SiC, which will hopefully achieve high-efficiency and ultra-precision machining.

Feasibility studies on wet grinding of carbon fibre reinforced epoxy polymer at minimum defect condition via eccentric sleeve grinding

Although surface grinding is reported to be capable of precision material removal in carbon fibre reinforced epoxy polymer composites (CFRPs), it is highly limited by deprived cutting temperature dissipation, tool wear and sensitivity to undesired cutting defects. Continuous engagement of abrasive grains and successive accumulation of heat at cutting interface in conventional surface grinding results in severe surface damages. Though the controlled application of cutting fluids exhibited improved surface integrity, entrapment of fluid droplets into the defective zones/cracks of fibre, matrix and its interfaces are shown to be stimulating further defect propagation. Present paper investigates the feasibility of improving cutting fluid application in CFRP grinding, establishing a minimum surface defect condition through eccentric sleeve grinding (ESG). The reduction of post-grinding surface defects through an intermittent-progressive cutting scheme in ESG is demonstrated and the efficacy of cutting fluids in such a grinding scheme is illustrated through the comparison of grinding forces and surface characteristics.

Aerodynamic Differences between New and Used Soccer Balls

The surface structure of soccer balls, such as the number and shapes of the ball panels, has recently changed, and research on the aerodynamics and flight trajectories of new soccer balls is actively proceeding. However, these studies are focused on new soccer balls, whereas the used soccer balls were never studied. In this study, the aerodynamic characteristics of soccer balls kicked 1000 times by a robot were investigated through wind tunnel tests. The results were compared with those obtained using new soccer balls. Regarding the aerodynamic characteristics of the soccer balls, it was found that the critical Reynold number, Recrit, changes with usage. This is related to the transition from laminar to turbulent flow of airflow around the ball. The comparison of the drag coefficients of the balls at Recrit showed that the drag coefficients of the new and used Telstar18 balls were 0.15 (Re = 2.5 × 105) and 0.14 (Re = 2.2 × 105), respectively; those of the new and used Merlin were 0.13 (Re = 2.8 × 105) and 0.13 (Re = 2.2 × 105), respectively; and finally, those of the new and used Derbystar were 0.14 (Re = 2.1×105) and 0.14 (Re = 2.1×105), respectively. The surface conditions of a soccer ball, such as the surface roughness and surface damages, are essential factors to determine the aerodynamics of the soccer balls.

Calculation of wear of teeth of open tooth gears

Abrasive wear and, in particular, wear of gear couplings in the presence of abrasive particles is studied. Under conditions of contact abrasive wear, with an increase in steel hardness and carbon content, the volumes of single surface damages caused by crushing of abrasive particles decrease, while the process does not qualitatively change. The direct fracture of the material in wear continues to be decisive. Keywords: gear coupling, wear, adhesion, abrasive grains, loading, friction force [email protected]

In-Process Monitoring of Laser Surface Modification

The laser cleaning process has the potential to become an alternative to the existing chemical-based cleaning process if integrated with an effective in-process monitoring system that could serve as a control mechanism over surface damages or contaminants through which the desired surface cleanliness could be achieved. This paper presents results of an investigation into the characteristics and viability of utilizing probe beam reflection (PBR) and laser plume-emission spectroscopy (PES) as respective integrated monitoring systems during and after cleaning of titanium alloy sheets using a frequency-tripled Nd:YAG laser. The results present the probe beam reflection as a better system with the ability to differentiate between cleaned and un-cleaned surfaces for both small and large surface areas.

Integrated Western and Chinese Medicine Interventions for Atopic Dermatitis: A Systematic Review and Meta-analysis

BackgroundAtopic Dermatitis (AD) is a chronic relapsing skin disease characterized by recurring episodes of itchiness with skin erythema and surface damages. Chinese medicine (CM) is widely used for the management of AD in China not only by its own, but also used in combination with conventional therapy (integrated Western-Chinese medicine, ICWM) in China. Although many clinical trials on the effectiveness of ICWM on AD have been reported; however, up to date, no sound evidence has been established on the clinical effectiveness and safety of ICWM for AD. ObjectivesTo systematically review the currently available clinical evidence on the clinical effectiveness and safety of ICWM for AD. MethodsRandomized and quasi-randomized controlled trials, which investigated ICWM interventions with at least one control group using the same conventional interventions, no treatment or placebo treatment, were included. Four English (CENTRAL, MEDLINE, EMBASE, AMED) and three Chinese (CNKI, CBM, WanFang Med) databases were searched. Risk of bias was assessed according to the Cochrane’s tool. Meta-analysis were performed to pool the data. ResultsFrom 1473 database entries, 55 studies were included, of which 5953 participants aged between 35 days to 67 years old were involved. Duration of treatment ranged from 1 to 24 weeks. Only 2 studies were judged to be at low risk of bias, 3 studies at unclear risk of bias, and the other 50 studies at high risk of bias. The research findings suggested that ICWM was superior over WM alone in improving clinical severity of AD (measured by EASI, SCORAD), health-related quality of life (measured by CDLQI, DLQI), long term control of AD (recurrence rate), patients/ investigator global score (effectiveness rate), and serum IgE level. No more adverse events associated with ICWM was found when compared with WM alone. ConclusionAdopting ICWM may be superior to using WM alone in managing AD without risk of more adverse events. However, the current available evidence is still too weak to generate conclusive results.