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New type desktop head-up display (HUD) can reduce visual fatigue and protect vision through long viewing distance. In this study, participants evaluated visual performance, fatigue, and discomfort of desktop HUD under two contrast polarity (N = 36) and five display luminance levels (N = 21). A positive polarity advantage was found over negative in visual fatigue and discomfort (p < .05). Statistically significant effect of luminance was found on visual performance, fatigue, and discomfort (p < .05). The calculated optimum display luminance by the proposed inverted-U fitted model was 153 cd/m2 under 300 lx, higher than that of traditional desktop displays. It is speculated that higher luminance is required to offset the reduction in contrast sensitivity due to smaller target angular size, which caused by longer viewing distance. These findings suggest that positive polarity and 153 cd/m2 can be used to improve performance and avoid fatigue and discomfort when utilising desktop HUD under 300 lx.
A visual ergonomic study was conducted on new type desktop HUD. With visual performance, fatigue, and discomfort as optimisation goals, positive polarity and 153 cd/m2 was recommended under 300 lx. Compared with traditional desktop displays, higher luminance was required in desktop HUD under the same illumination.
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Objective: Laparoscopic cholecystectomy (LC) combined with laparoscopic common bile duct exploration (LCBDE) and endoscopic retrograde cholangiopancreatography (ERCP) or endoscopic sphincterotomy (EST) combined with LC are the two primary treatment modalities for common bile duct stones (CCL) at present. The aim of this study is to compare the efficacy and safety of the two surgical approaches in treating CCL and analyze the risk factors for the recurrence of common bile duct stones. Methods: The clinical data of 148 CCL patients treated in the hospital from March 2014 to March 2016 were retrospectively analyzed. ERCP+LC was performed for 74 patients (ERCP+LC group), while the remaining 74 patients underwent LC+LCBDE (LC+LCBDE group). The success rate of lithotomy, operation time, total hospital stay time, postoperative hospital stay time, clinical symptoms, incidence rate of complications, and hospitalization expenses were compared between the two groups. The patients were followed up, the recurrence of choledocholithiasis was recorded, and the risk factors for recurrence were analyzed. Results: The success rate of lithotomy was 97.3% in the LC+LCBDE group and 94.6% in the ERCP+LC group. In the ERCP+LC group and LC+LCBDE group, the average operation time was (125.7±20.3) min and (106.5±25.4) min, the postoperative anal ventilation time was (20.8±3.5) d and (18.7±3.7) d, and the postoperative hospital stay time was (9.3±3.1) d and (7.7±3.3) d, respectively. It can be seen that the above three indexes were all significantly shorter in the LC+LCBDE group than those in ERCP+LC group (P < .001, P < .001, P = .003). The hospitalization expenses in the LC+LCBDE group [(19±1) thousand yuan] were obviously lower than those in the ERCP+LC group [(26±2) thousand yuan] (P < .001). The postoperative symptoms included fever, vomiting, abdominal pain and abdominal distension. The incidence rate of abdominal pain in the LC+LCBDE group was far higher than that in the ERCP+LC group (P = .025), and that of the remaining symptoms had no statistically significant difference between the two groups (P > .05). The postoperative complications mainly included incision infection, bile duct bleeding, biliary fistula, abdominal infection, bile duct pneumatosis, cholangitis and acute pancreatitis. Hyperamylasemia occurred in 8 cases after operation in the ERCP+LC group, greatly more than that in the LC+LCBDE group (1 case) (P = .016), while the incidence of other complications had no statistically significant difference between the two groups (P > .05). The patients were followed up for 3-5 years, and it was found that the recurrence rate of choledocholithiasis was 17.6% and 13.5%, and the mean postoperative recurrence time was 13.7 months and 13.9 months, respectively, in ERCP+LC group and LC+LCBDE group. The results of multivariable logistic regression analysis revealed that the level of cholesterol >572 mm/L (OR=5.108, 95%CI: 1.263-11.472, P = .038), choledochectasia (OR=2.165, 95%CI: 1.019-8.418, P = .034) and parapapillary diverticulum (OR=6.761, 95%CI: 1.334-15.613, P = .039) were independent risk factors for postoperative recurrence of choledocholithiasis. Conclusions: In our study, we found that ERCP+LC and LC+LCBDE have definite efficacy in the treatment of CCL. Patients treated with LC+LCBDE need short hospital stay time and low treatment expenses and have relatively few long-term complications.
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The self-luminous cockpit displays need to be adaptive to a wide range of ambient light levels, which changes from very low illuminance to very high levels. Yet, current studies on evaluation and luminance setting of displays in bright surroundings are still limited. In this study, a three-dimensional visual ergonomic experiment was carried out to investigate how bright a cockpit display should be to meet aircrew operational requirements under different illuminance. A lab study with a within-subjects (N = 12) design was conducted in a simulated cockpit. According to the Weber-Fechner's Law, human observers evaluated five display luminance conditions (101, 101.5, 102, 102.5, 103 cd/m2) under five ambient illuminance conditions (10°, 101, 102, 103, 104 lx). Visual performance, visual fatigue and visual comfort were used as evaluation bases, which were measured by d2 task, subjective fatigue questionnaire and visual perception semantic scales. Nonlinear function fitting was used to calculate the optimal luminance under a certain illuminance. Finally, curvilinear regression was used to analyze the illuminance and its corresponding optimal luminance. Based on Silverstein luminance power function, a luminance adjustment model with the form of power function was obtained. The proposed three-dimensional model fits the experimental data well and is consistent with the existing studies. It can be regarded as a supplement and optimization of the previous model under high ambient illuminance. This study can contribute not only to the pleasing luminance setting of panel displays in aircraft cockpits but also to other self-luminous devices, such as tablet devices, outdoor monitoring equipment and advertising screens.
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Luz , Percepción Visual , Humanos , Presentación de DatosRESUMEN
Light is an important external factor that affects human circadian rhythms. This study aimed to explore the effects of different dimensions of diurnal light exposure on the physiological circadian phase shift (CPS) of the human body. A strict light exposure experiment with different timing schemes (8:00-12:00, 13:00-17:00, 18:00-22:00), durations (4 h, 8 h) and effective circadian stimulus levels (circadian stimulus: 0.35, 0.55) was performed in an enclosed laboratory. Fourteen participants, including seven males and seven females, with a mean age of 24.29 ± 2.43 (mean ± standard deviation), participated in this experiment and experienced all six lighting schemes. The results showed that both time factor (F 3,40 = 29.079, p < 0.001, the power of the sample size = 0.98) and circadian stimulus levels (T 20 = - 2.415, p = 0.025, the power of sample size = 0.76) significantly affect the CPS. On this basis, a diurnal circadian lighting accumulation (DCLA)-CPS model was proposed in the form of the Boltzmann function, and was validated by experimental data with high correlation (R 2 = 0.9320, RSS = 0.1184), which provides strong support for rationally arranging the light level at different times of the day.