High luminous efficiency and excellent thermal performance in rod-shaped YAG:Ce phosphor ceramics for laser lighting.

High power and high brightness laser lighting puts forward new requirements for phosphor converters such as high luminous efficiency, high thermal conductivity and high saturation threshold due to the severe thermal effect. The structure design of phosphor converters is proposed as what we believe to be a novel strategy for less heat production and more heat conduction. In this work, the rod-shaped YAG:Ce phosphor ceramics (PCs) and disc-shaped YAG:Ce PCs as control group were fabricated by the gel casting and vacuum sintering, to comparatively study the luminescence performance for LD lighting, on the premise that the total number of transverse Ce3+ ions and the volume of samples from two comparison groups were same. All rod YAG:Ce PCs with low Ce3+ concentration exhibited the high luminous efficiency and better thermal stability than YAG:Ce discs with high Ce3+ concentration. Under the laser power density of 47.8 W/mm2, the luminous saturation was never observed in all rod-shaped YAG:Ce PCs. The high luminous efficacy of 245∼274 lm/W, CRI of 56.3∼59.5 and CCT of 4509∼4478 K were achieved. More importantly, due to the extremely low Ce3+ doping concentration (0.01 at%), rod-shaped ceramics based LDs devices showed the excellent thermal performance and their surface temperatures were even below 30.5 °C surprisingly under the laser power density of 20.3 W·mm-2 (2 W). These results indicate that the rod shape of phosphor converter is a promising structure engineering for high power laser lighting.

High luminous efficiency and high saturation threshold in highly transparent LuAG:Ce phosphor ceramics for laser diodes lighting.

Lu3Al5O12:Ce (LuAG:Ce) phosphor ceramics (PCs) with the excellent thermal stability and high saturation threshold are considered as the best green-fluorescent converters for high-power laser diodes (LDs) lighting. In this study, the effects of sintering additives and sintering processes on the transmittance and microstructure of LuAG:Ce PCs were systematically studied, and the luminescence performance of ceramics with different transmittance was compared. LuAG:Ce PCs with the transmittance of 80% (@800 nm, 1.5 mm) were obtained by using 0.1 wt.% MgO and 0.5 wt.% TEOS as sintering additives, combined with optimized vacuum pre-sintering and hot isostatic pressing. Compared to the non-HIP samples, the transmittance had increased by 11%. The microstructure of ceramics indicated that high transparency was closely related to the decrease in intergranular pores. Notably, the luminous efficiency of 253 lm/W and its saturation thresholds of > 46 W/mm2 were obtained simultaneously in green-emitting LDs devices. Moreover, under 3W laser irradiation, highly transparent ceramics had the low surface temperature of 66.4 °C, indicating the good heat dissipation performance. The observed high luminous efficiency and high saturation threshold of LuAG:Ce PCs were attributed to fewer pores and oxygen vacancies. Therefore, this work proves that highly transparent LuAG:Ce PCs are promising green-fluorescent converters for high-power LDs lighting.

Rasch analysis of the 32-item motor function measure in ambulant patients with Duchenne muscular dystrophy.

OBJECTIVE: This study analyzed the 32-item Motor Function Measure in a cohort of ambulatory patients with Duchenne muscular dystrophy using Rasch measurement methods. DESIGN: This is a psychometric study. SETTING: Rehabilitation centre of a large public children's hospital in Shenzhen, China. PARTICIPANTS: Data from 176 genetically confirmed ambulant patients with Duchenne muscular dystrophy (mean age 7.3 years, SD 2.3 years, range 3.1-13.1 years) were analyzed. RESULTS: Rasch analyses supported the Motor Function Measure domain D1 as a reliable (person reliability = 0.88, person separation index = 2.71) and valid (acceptable targeting, little misfit, minimal category disordering) measure in ambulant patients with Duchenne muscular dystrophy. Remodelling the domain D1 by collapsing item 25 from 4 to 3 response categories addressed the problematic disordered thresholds, resulting in a rebuilt domain D1 with enhanced measurement properties. However, findings for domains D2 and D3 did not fulfil most Rasch model expectations. There were disordered thresholds for most items in domains D2 and D3, with low reliability coefficients, item mistargeting and misfit, and large ceiling effects. CONCLUSION: Rasch analyses confirmed that the Motor Function Measure domain D1 was reliable and valid and provided a unidimensional measure for motor function in ambulant Duchenne muscular dystrophy patients. Accuracy of measurement had been enhanced through remodelling, and a rebuilt domain D1 with category collapsing for item 25 was proposed. The analysis revealed multiple limitations of the domains D2 and D3 that certain essential psychometrics were poorly met and, therefore, should be used with caution in this patient group.

Chronic pain, psychological distress, and quality of life in males with Duchenne muscular dystrophy.

AIM: To describe chronic pain in Duchenne muscular dystrophy (DMD) from children's/adolescents' perspectives, explore patient variables associated with self-reported pain, and examine the relationship between chronic pain, psychological functioning, and health-related quality of life (HRQoL). METHOD: This observational study included a paediatric cohort (aged 8-18 years; median age 9 years 4 months) with DMD under multidisciplinary care (n = 45). Clinical data of the latest visit were extracted from the electronic health record and assessment of pain, psychological distress, and HRQoL were performed during the same visit. RESULTS: Thirty-two patients reported pain during the previous 4 weeks, and 18 reported persistent or recurrent chronic pain. Average pain intensity of chronic pain was mild, with regions of the legs (n = 12), lower back (n = 6), hips (n = 6), and shoulder (n = 6) most frequently affected. Older age, higher body mass index, being non-ambulatory, wheelchair dependency, and spinal deformities were contextual variables related to the presence of chronic pain. Furthermore, chronic pain was significantly associated with psychological distress and reduced HRQoL in paediatric patients with DMD. INTERPRETATION: Chronic pain in paediatric DMD is frequent and widespread, highlighting the need for pain to be addressed in the routine care of affected young people. Chronic pain may make a significant contribution to psychological distress and impaired HRQoL in paediatric patients with DMD. WHAT THIS PAPER ADDS: Chronic pain differs in aetiology, scope, and nature compared with acute pain in paediatric Duchenne muscular dystrophy (DMD). Older age, higher body mass index, being non-ambulatory, wheelchair dependency, and spinal deformities are important patient variables. Chronic pain is significantly associated with psychological distress and reduced health-related quality of life in paediatric DMD.

Responsiveness and Minimal Clinically Important Difference of the Chinese Version of the Motor Function Measure-32 in Children and Adolescents with Duchenne Muscular Dystrophy.

PURPOSE: This study aimed to examine the responsiveness and minimal clinically important difference of the Motor Function Measure 32-Chinese version (MFM 32-CN) in children and adolescents with Duchenne muscular dystrophy (DMD). METHODS: This observational, prospective cohort study assessed changes in motor function over 12 months using the MFM 32-CN in 108 pediatric patients with DMD. RESULTS: Moderate to high internal responsiveness was found for MFM total, D1, and D2 scores (SRM = 0.46-0.83). Sufficient external responsiveness was observed in all MFM scores, as determined by a good correlation with the Patient Global Impression of Change (PGIC) ratings (r = 0.54-0.72, p < .01). The estimated MCID values derived from different anchor-based methods ranged from 4.7 to 6.0, with a median of 5.0 points (%). CONCLUSION: The MFM 32-CN demonstrates sufficient internal and external responsiveness as a measure of motor function in children and adolescents with DMD. The present study established the MCID of MFM-32 in pediatric patients with DMD.

Enhanced CO Sensing Performances of PdO/WO3 Determined by Heterojunction Structure under Illumination.

The CO sensing performances and mechanism of PdO/WO3-based sensors were investigated by experiments and density functional theory calculations. The CO sensing performance can be significantly enhanced by decorating WO3 with PdO, which is attributed to the catalyst (chemical sensitization) and P-N junction (electronic effect). On the one hand, PdO is an excellent catalyst used to promote the adsorption of oxygen species. On the other hand, the constructed P-N junction structure between PdO and WO3 can facilitate the migration of carriers and suppress the recombination of electrons and holes, which promote the adsorption of more oxygen species. Furthermore, the calculation results verify that decorating WO3 with PdO can significantly enhance the CO sensing response by providing more adsorption sites available for oxygen species and make more electrons to transfer from CO to PdO/WO3 configuration. Moreover, the band gap energies of the WO3 sensor can be reduced by PdO decoration, and the light absorption range in the visible light region can be expanded. More photogenerated electron-hole pairs can be produced based on the P-N junction structure, which can promote the progress of electrochemical reactions. Thus, the PdO/WO3 material can be a promising candidate to detect CO, and it can effectively utilize the UV-visible light to destruct the CO contaminant.

Study of domain configurations in (Bi,Na)ZrO3-modified (K,Na)(Nb,Sb)O3 piezoelectric ceramics by acid-etching at different temperatures.

Domain structure often greatly affects piezoelectric performance of a ferroelectric ceramic. Accordingly, a convenient method that can well characterize the domain structure at various temperatures is highly desired for understanding the underlying mechanism. An improved acid-etching technique was recently developed for such purpose. Domain structure of poled 0.96(K0.48Na0.52)(Nb0.96Sb0.04)O3-0.04(Bi0.50Na0.50)ZrO3 ceramics with a large piezoelectric coefficient d33 of 535 pC/N was systematically investigated at three typical temperatures. It was found that domain configurations change significantly with temperature. Hierarchical nanodomain structure is widely observed in domain patterns acid-etched at 25 °C, due to the orthorhombic-tetragonal phase coexistence. By contrast, the majority part of those acid-etched at - 60 °C are simply some long parallel stripes, while a small amount of banded structure appears in broad stripes inside some grains. A nearly 63° intersectional angle is seen between two adjacent sets of parallel stripes in the domain pattern of a cuboid-shaped grain, indicating that orthorhombic phase remains down to - 60 °C. The domain patterns acid-etched at 80 °C become even simpler, mainly consisting of long parallel stripes that are several hundred nanometers wide and have quite straight edges. Fundamental issues associating with the possible domain configurations and the acid-etching were discussed on the simple mathematical basis.