Ameliorating Uniformity and Color Conversion Efficiency in Quantum Dot-Based Micro-LED Displays through Blue-UV Hybrid Structures.

Quantum dot (QD)-based RGB micro light-emitting diode (µ-LED) technology shows immense potential for achieving full-color displays. In this study, we propose a novel structural design that combines blue and quantum well (QW)-intermixing ultraviolet (UV)-hybrid µ-LEDs to achieve high color-conversion efficiency (CCE). For the first time, the impact of various combinations of QD and TiO2 concentrations, as well as thickness variations on photoluminescence efficiency (PLQY), has been systematically examined through simulation. High-efficiency color-conversion layer (CCL) have been successfully fabricated as a result of these simulations, leading to significant savings in time and material costs. By incorporating scattering particles of TiO2 in the CCL, we successfully scatter light and disperse QDs, effectively reducing self-aggregation and greatly improving illumination uniformity. Additionally, this design significantly enhances light absorption within the QD films. To enhance device reliability, we introduce a passivation protection layer using low-temperature atomic layer deposition (ALD) technology on the CCL surface. Moreover, we achieve impressive CCE values of 96.25% and 92.91% for the red and green CCLs, respectively, by integrating a modified distributed Bragg reflector (DBR) to suppress light leakage. Our hybrid structure design, in combination with an optical simulation system, not only facilitates rapid acquisition of optimal parameters for highly uniform and efficient color conversion in µ-LED displays but also expands the color gamut to achieve 128.2% in the National Television Standards Committee (NTSC) space and 95.8% in the Rec. 2020 standard. In essence, this research outlines a promising avenue towards the development of bespoke, high-performance µ-LED displays.

Carpal tunnel syndrome in dentists compared to other populations: A nationwide population-based study in Taiwan.

BACKGROUND: Dentists may be at a higher risk of developing carpal tunnel syndrome (CTS) because of their use of frequent wrist and vibratory instruments at work; however, this issue remains unclear. Therefore, we conducted this study to clarify it. METHODS: Taiwan National Health Insurance Research Database was used for this nationwide population-based study. We identified 11,084 dentists, 74,901 non-dentist healthcare professionals (HCPs), and identical number of age- and sex-matched participants from the general population. Participants who had the diagnosis of CTS before 2007 were excluded. Between 2007 and 2011, the risk of developing CTS among dentists, non-dentist HCPs, and the general population was compared by following their medical histories. RESULTS: The cumulative incidence rate of CTS among dentists was 0.5% during the 5-year follow-up period. In dentists, the risk was higher in women (women: 0.7%; men: 0.4%) and older individuals (≥60 years: 1.0%; <60 years: 0.4%). After adjusting for age, sex, and underlying comorbidities, dentists had a lower risk of CTS than the general population (adjusted odds ratio [AOR]: 0.65, 95% confidence interval [CI]: 0.45-0.92). Dentists had a higher risk for CTS compared with non-dentist HCPs, although the difference was not statistically significant (AOR: 1.21; 95% CI: 0.90-1.64). CONCLUSIONS: In CTS, dentists had a lower risk than the general population and a trend of higher risk than non-dentist HCPs. The difference between dentists and non-dentist HCPs suggests that we should pay attention to dentists for potential occupational risk of this disease. However, further studies are warranted to better clarify it.

Recent Advances in Micro-LEDs Having Yellow-Green to Red Emission Wavelengths for Visible Light Communications.

Visible light communication (VLC), which will primarily support high-speed internet connectivity in the contemporary world, has progressively come to be recognized as a significant alternative and reinforcement in the wireless communication area. VLC has become more popular recently because of its many advantages over conventional radio frequencies, including a higher transmission rate, high bandwidth, low power consumption, fewer health risks, and reduced interference. Due to its high-bandwidth characteristics and potential to be used for both illumination and communications, micro-light-emitting diodes (micro-LEDs) have drawn a lot of attention for their use in VLC applications. In this review, a detailed overview of micro-LEDs that have long emission wavelengths for VLC is presented, along with their related challenges and future prospects. The VLC performance of micro-LEDs is influenced by a number of factors, including the quantum-confined Stark effect (QCSE), size-dependent effect, and droop effect, which are discussed in the following sections. When these elements are combined, it has a major impact on the performance of micro-LEDs in terms of their modulation bandwidth, wavelength shift, full-width at half maximum (FWHM), light output power, and efficiency. The possible challenges faced in the use of micro-LEDs were analyzed through a simulation conducted using Crosslight Apsys software and the results were compared with the previous reported results. We also provide a brief overview of the phenomena, underlying theories, and potential possible solutions to these issues. Furthermore, we provide a brief discussion regarding micro-LEDs that have emission wavelengths ranging from yellow-green to red colors. We highlight the notable bandwidth enhancement for this paradigm and anticipate some exciting new research directions. Overall, this review paper provides a brief overview of the performance of VLC-based systems based on micro-LEDs and some of their possible applications.

Design and Simulation of InGaN-Based Red Vertical-Cavity Surface-Emitting Lasers.

We propose a highly polarized vertical-cavity surface-emitting laser (VCSEL) consisting of staggered InGaN multiple quantum wells (MQWs), with the resonance cavity and polarization enabled by a bottom nanoporous (NP) n-GaN distributed Bragg reflectors (DBRs), and top TiO2 high-index contrast gratings (HCGs). Optoelectronic simulations of the 612 nm VCSEL were systematically and numerically investigated. First, we investigated the influences of the NP DBR and HCG geometries on the optical reflectivity. Our results indicate that when there are more than 17 pairs of NP GaN DBRs with 60% air voids, the reflectance can be higher than 99.7%. Furthermore, the zeroth-order reflectivity decreases rapidly when the HCG's period exceeds 518 nm. The optimal ratios of width-to-period (52.86 ± 1.5%) and height-to-period (35.35 ± 0.14%) were identified. The staggered MQW design also resulted in a relatively small blue shift of 5.44 nm in the emission wavelength under a high driving current. Lastly, we investigated the cavity mode wavelength and optical threshold gain of the VCSEL with a finite size of HCG. A large threshold gain difference of approximately 67.4-74% between the 0th and 1st order transverse modes can be obtained. The simulation results in this work provide a guideline for designing red VCSELs with high brightness and efficiency.

Comparison of the Risk for Peripheral Vertigo between Physicians and the General Population.

BACKGROUND: Because of the limited information available regarding peripheral vertigo (PV) in physicians, we conducted this study to clarify this issue. METHODS: We used Taiwan National Health Insurance Research Database to identify 26,309 physicians and an identical number of general population matched by age and sex. All the participants who had PV before 2007 and residents were excluded. By tracing their medical histories between 2007 and 2013, comparisons of PV risk between physicians and general population and among physicians were performed. RESULTS: Physicians had a significantly lower PV risk than the general population (adjusted odds ratio [AOR]: 0.811; 95% confidence interval [CI]: 0.662-0.994). In comparison among physicians, otolaryngologists had a significantly higher PV risk than other specialties. Physicians who were older or served in local hospitals or clinics had a significantly higher PV risk than physicians in medical centers. CONCLUSION: Physicians had a significantly lower PV risk than the general population. Better medical knowledge in physicians than in the general population may explain the findings; however, further studies are warranted for elucidating the detailed mechanisms.

Asymmetrical bidirectional optical wireless communication system based on a transmissive 1D LC-SLM for NG-PON2.

An asymmetric bidirectional optical wireless communication (B-OWC) system using optical fibers as the transmitter and receiver and capable of wavelength switching is proposed for next generation passive optical network stage two (NG-PON2) extension to home area network (HAN), without optical/electrical (O/E) and electrical/optical (E/O) conversions, which is based on a transmissive "floating" pixel size one-dimensional (1D) liquid crystal spatial light modulator (LC-SLM) at the access node (AN) and a modulated retroreflector (MRR) at the terminal user (TU). The utilization of a reflective grating element and a low-cost LC-SLM in the AN offers a high flexibility of beam steering and wavelength selection in the scenario of B-OWC. Instead of a light source used at conventional TU, a MRR was employed at a TU in order to improve the problems of the power consumptions, alignment difficulties, wavelength contentions, and cost of the TUs. Downlink and uplink data transmissions at a link speed over 2.5 Gbits/s, using wavelengths between 1590∼1603nm and 1524∼1544nm, respectively, corresponding to the downlink and uplink wavelengths specified by the NG-PON2 standard, have been experimentally demonstrated successfully, with quality factors (Q-factors) beyond the forward error correction limit (Q-factor=16.9dB, bit error rate=10-12).

Comparison of the risk of developing lumbar herniated intervertebral disc between dentists and other occupations: A nationwide population-based study in Taiwan.

OBJECTIVES: Dentists may have a higher risk of developing lumbar herniated intervertebral disc (HIVD) due to prolonged sitting and improper postures during work. We conducted this study to delineate this issue, which is still unclear. METHODS: This nationwide population-based study was conducted using Taiwan National Health Insurance Research Database. We identified 10 734 dentists, 72 066 non-dentist health-care providers (HCPs), and an identical number of age- and gender-matched participants from the general population. The risk of developing lumbar HIVD among dentists, non-dentist HCPs, and general population was compared by tracing their medical histories between 2007 and 2011. RESULTS: The cumulative incidence rate of lumbar HIVD among dentists during the 5-year follow-up period was 1.40%. After adjusting for age, gender, and comorbidities, the risk of developing lumbar HIVD was found to be lower among dentists than that among the general population (adjusted odds ratio [AOR]: 0.80, 95% confidence interval [CI]: 0.64-1.00) and non-dentist HCPs (AOR: 0.81, 95% CI: 0.68-0.96). CONCLUSIONS: Dentists in Taiwan have a lower risk of developing lumbar HIVD than that among other occupations. Although this result is different from the general cognition, it does not imply that the prevention of lumbar HIVD in dentists is not important. Further studies are warranted to better address this issue.

Validation of Decision Groups in Patients with Dengue Fever: A Study during 2015 Outbreak in Taiwan.

The management of dengue fever (DF) has been suggested to be categorized into decision groups A, B, and C; however, its usefulness in predicting mortality is still unclear, and hence we conducted this study to clarify this issue. We conducted a study by recruiting 2,358 patients with DF from the 2015 outbreak in the Chi-Mei Medical Center. Demographic data, vital signs, clinical symptoms and signs, coexisting morbidities, laboratory data, decision groups categorized according to World Health Organization for clinical management of dengue in 2012, and 30-day mortality rates were included for analysis. The overall 30-day mortality rate was 1.4%. The 30-day mortality rates in decision groups A, B, and C were 0%, 0.5%, and 46.2%, respectively. Compared with Group A, there was a higher mortality risk in Group C (odds ratio [OR]: 1,480, 95% confidence interval [CI]: 195-11,200). The area under the curve of the variable of Group C was excellent (OR: 0.92, 95% CI: 0.85-0.99). The sensitivity, specificity, positive predictive value, and negative predictive value for predicting 30-day mortality in Group C were 88.2%, 98.5%, 46.2%, and 99.8%, respectively. This study showed that decision Group C has a good predictive value for 30-day mortality. Further studies including validation in other nations are warranted.

Comparing the antiswelling and analgesic effects of three different ice pack therapy durations: a randomized controlled trial on cases with soft tissue injuries.

BACKGROUND: Ice pack therapy has been widely used in treatment for soft tissue injuries. However, no studies have yet explored the most appropriate and effective duration for ice therapy with ice packs. PURPOSE: This study explored the antiswelling and analgesic effects of different ice pack therapy durations on soft tissue injuries as well as patient discomfort. METHODS: An experimental design including pretest and three posttests with three groups was used in this study. Using convenience sampling and randomized block assignment, 99 participants with soft tissue injuries from the emergency department of a medical center in southern Taiwan were included in this study. With 33 participants in each group, three groups with ice pack therapy for 10, 20, and 30 minutes were indicated to compare skin temperature, swelling, and pain differences in ice-treated areas as well as participant discomfort. RESULTS: This study found no significant differences in the effect of different ice pack therapy durations among the three groups. However, this study identified significant differences between pretest and each posttest in terms of changes in skin temperature, pain, and numbness and rash-related discomfort in each group. CONCLUSION/IMPLICATIONS FOR PRACTICE: Research results found that the three different ice pack therapy durations could lower skin temperature and reduce partial pain. The different ice pack therapy durations would cause similar discomfort incidence rates in the three groups. Ice pack therapy for 10 minutes could reduce partial swelling and pain effectively. Accordingly, we suggest that 10 minutes is the optimal ice pack therapy duration for persons with soft tissue injuries. However, the ice pack therapy duration should be adjusted according to individual needs and situation.