Novel Mn4+-activated LiLaMgWO6 far-red emitting phosphors: high photoluminescence efficiency,good thermal stability,and potential applications in plant cultivation LEDs

Double perovskite-based LiLaMgWO₆:Mn⁴⁺ (LLMW:Mn⁴⁺) red phosphors were synthesized by traditional solid-state route under high temperature, and they showed bright far-red emission under excitation of 344 nm. The crystal structure, luminescence performance, internal quantum efficiency, fluorescence decay lifetimes, and thermal stability were investigated in detail. All samples exhibited far-red emissions around 713 nm due to the ²E_g → ⁴A_2g transition of Mn⁴⁺ under excitation of near-ultraviolet and blue light, and the optimal doping concentration of Mn⁴⁺ was about 0.7 mol%. The CIE chromaticity coordinates of the LLMW:0.7% Mn⁴⁺ sample were (0.7253, 0.2746), and they were located at the border of the chromaticity diagram, indicating that the phosphors had high color purity. Furthermore, the internal quantum efficiency of LLMW:0.7% Mn⁴⁺ phosphors reached up to 69.1%, which was relatively higher than those of the reported Mn⁴⁺-doped red phosphors. Moreover, the sample displayed good thermal stability; the emission intensity of LLMW:0.7% Mn⁴⁺ phosphors at 423 K was 49% of the initial value at 303 K, while the activation energy was 0.39 eV. Importantly, there was a broad spectral overlap between the emission band of LLMW:Mn⁴⁺ phosphors and the absorption band of phytochrome P_FR under near-ultraviolet light. All of these properties and phenomena illustrate that the LLMW:Mn⁴⁺ phosphors are potential far-red phosphors for applications in plant cultivation LEDs.

Novel Mn⁴⁺-activated LiLaMgWO₆ far-red emitting double-perovskite phosphors with high photoluminescence efficiency and good thermal stability were developed for applications in plant cultivation LEDs.     

Thermally stable La2LiSbO6:Mn4+,Mg2+ far-red emitting phosphors with over 90% internal quantum efficiency for plant growth LEDs

In this paper, we reported on the high-efficiency and thermally-stable La₂LiSbO₆:Mn⁴⁺,Mg²⁺ (LLS:Mn⁴⁺,Mg²⁺) far-red emitting phosphors. Under 338 nm excitation, the composition-optimized LLS:0.3%Mn⁴⁺,1.6%Mg²⁺ phosphors which were made up of [SbO₆], [LiO₆], and [LaO₈] polyhedrons, showed intense far-red emissions peaking at 712 nm (²E_g → ⁴A_2g transition) with internal quantum efficiency as high as 92%. The LLS:0.3%Mn⁴⁺,1.6%Mg²⁺ phosphors also exhibited high thermal stability, and the emission intensity at 423 K only reduced by 42% compared with its initial value at 303 K. The far-red light-emitting device has also been made by using the LLS:0.3%Mn⁴⁺,1.6%Mg²⁺ phosphors and a 365 nm emitting InGaN chip, which can emit far-red light that is visible to the naked eye. Importantly, the emission spectrum of the LLS:0.3%Mn⁴⁺,1.6%Mg²⁺ phosphors can match well with the absorption spectrum of phytochrome P_FR, indicating the potential of these phosphors to be used in plant growth light-emitting diodes.

Double perovskite La₂LiSbO₆:Mn⁴⁺,Mg²⁺ far-red emitting phosphors with internal quantum efficiency as high as 92% and good thermal stability were developed for plant growth LEDs.     

Preparation,characterization, and luminescence properties of double perovskite SrLaMgSbO6:Mn4+ far-red emitting phosphors for indoor plant growth lighting

Mn⁴⁺-activated SrLaMgSbO₆ far-red emitting phosphors with double perovskite structure were prepared by traditional solid-state reaction. The research on the crystal structure of the SrLaMgSbO₆:0.8%Mn⁴⁺ (SLMS:0.8%Mn⁴⁺) phosphors showed that the as-prepared sample was made up of two polyhedrons, [SbO₆] and [MgO₆]. Under the excitation of 333 nm, the SLMS:0.8%Mn⁴⁺ phosphors exhibited an intense far-red emission in the 625–800 nm wavelength range with CIE chromaticity coordinates of (0.733, 0.268), which could match well with the absorption spectrum of phytochrome P_FR. The optimal concentration of Mn⁴⁺ ions in the SLMS:Mn⁴⁺ phosphors was 0.8 mol%. Importantly, the as-prepared SLMS:0.8%Mn⁴⁺ phosphors had an internal quantum efficiency of 35%. The thermal stability of SLMS:0.8%Mn⁴⁺ phosphors was also investigated, and the activation energy was found to be 0.3 eV. Thus, the Mn⁴⁺-activated SLMS phosphors have great potential to serve as far-red emitting phosphors in indoor plant growth lighting.

Novel far-red emitting double perovskite SrLaMgSbO₆:Mn⁴⁺ phosphors were prepared and their photoluminescence properties were studied for applications in indoor plant growth lighting.     

A critical appraisal of pinhole scintigraphy of the ankle and foot

BACKGROUND: Scintigraphy is an established imaging technique for injuries of the ankle and foot that are not apparent on plain radiographs. The scintigraphic technique has varied, with planar and pinhole images being used. MATERIALS AND METHODS: The incremental value of pinhole scintigraphy over planar imaging was studied in 16 patients with established diagnoses. Inter-reporter reproducibility was also measured. RESULTS: Pinhole scintigraphy improved the diagnostic specificity in nearly one half of the patients (48%). It did not contribute substantial information in 46% and led to confusion in the diagnosis of one patient. Inter-reporter agreement was good, with a kappa value of 0.78. Diagnoses varied from fractures of the talar dome to avulsion fractures of the malleoli and impingement syndromes. CONCLUSIONS: Pinhole images add a significant incremental value to planar scintigraphy of the foot and ankle. Although this had been perceived intuitively in the past, it has not been critically evaluated. The technique has good inter-reporter agreement.     

Advanced uterovaginal prolapse: is vaginal hysterectomy with McCall culdoplasty as effective as in lesser degrees of prolapse?

Introduction and hypothesis

There is a paucity of data on the success of vaginal surgery for severe prolapse. The authors hypothesized that the success rates of total vaginal hysterectomy (TVH) with McCall culdoplasty in women with advanced pelvic organ prolapse (POP) and in women with less severe POP are similar.

Methods

This was a retrospective review of women undergoing TVH with McCall culdoplasty from 2005 to 2014. Advanced POP was defined as exteriorized uterovaginal prolapse with Pelvic Organ Prolapse Quantification (POP-Q) point C, Ba or Bp ≥50% of the total vaginal length. The primary aim was to compare surgical success of TVH with McCall culdoplasty for the repair of advanced POP and less severe POP at ≥1 year.

Results

A total of 311 women were included, 38 with advanced POP and 273 with less severe POP. Women with advanced POP were older (71.6 vs. 61.8 years, respectively; p < 0.0001), but there were no significant differences in the length of follow-up (102.5 vs. 117 weeks, p = 0.2378), success rates (76.3% vs. 68.5%, p = 0.3553) or reoperation rates (2.6% vs. 4%, p > 0.9999) between women with advanced POP and less severe POP, respectively. There was a higher failure rate in the anterior compartment in those with advanced POP (18.4% vs. 6.2%, p = 0.0168), but not in the apical or posterior compartment.

Conclusions

TVH with McCall culdoplasty is equally effective for the treatment of advanced uterovaginal prolapse as for the treatment of less severe POP. Surgeons should consider this traditional surgery for their patients even if they have high-stage uterovaginal prolapse.

     

Influence of Lifestyle Factors on Quantitative Heel Ultrasound Measurements in Middle-Aged and Elderly Men

We examined the distribution of quantitative heel ultrasound (QUS) parameters in population samples of European men and looked at the influence of lifestyle factors on the occurrence of these parameters. Men aged between 40 and 79 years were recruited from eight European centers and invited to attend for an interviewer-assisted questionnaire, assessment of physical performance, and quantitative ultrasound (QUS) of the calcaneus (Hologic; Sahara). The relationships between QUS parameters and lifestyle variables were assessed using linear regression with adjustments for age, center, and weight. Three thousand two hundred fifty-eight men, mean age 60.0 years, were included in the analysis. A higher PASE score (upper vs. lower tertile) was associated with a higher BUA (β coefficient = 2.44 dB/Mhz), SOS (β = 6.83 m/s), and QUI (β = 3.87). Compared to those who were inactive, those who walked or cycled more than an hour per day had a higher BUA (β = 3.71 dB/Mhz), SOS (β = 6.97 m/s), and QUI (β = 4.50). A longer time to walk 50 ft was linked with a lower BUA (β = ?0.62 dB/Mhz), SOS (β = ?1.06 m/s), and QUI (β = ?0.69). Smoking was associated with a reduction in BUA, SOS, and QUI. There was a U-shaped association with frequency of alcohol consumption. Modification of lifestyle, including increasing physical activity and stopping smoking, may help optimize bone strength and reduce the risk of fracture in middle-aged and elderly European men.     

In-house preparation of iodine -131 metaiodo benzyl guanidine for scintigraphy of neuroendocrine tumors. Fourteen years experience in South India

Iodine-131 metaiodobenzyl guanidine ((131)I-MIBG) is routinely used for imaging and treatment of neuroendocrine tumors (NET). As the commercially available radiopharmaceutical was very expensive, we developed an in-house method of labeling MIBG with (131)I in 1993. A total of 247 batches of (131)I-MIBG were prepared and used in our hospital between April 1993 and September 2006. We report our experience over these 14 years of preparation of this tracer in our hospital radiopharmacy, for the scintigraphy of NET. The technique of preparation is simple and the labeled product was found to be of acceptable quality. With the routine availability and cost effectiveness, the utilization of this radiopharmaceutical for scintigraphy increased remarkably in our institution.     

Mn4+-activated Li3Mg2SbO6 as an ultrabright fluoride-free red-emitting phosphor for warm white light-emitting diodes

In this paper, we report on highly efficient Mn⁴⁺-activated double perovskite Li₃Mg₂SbO₆ (LMS) red-emitting phosphors. These LMS:Mn⁴⁺ phosphors can be efficiently excited over a broad wavelength band from 235 nm to 600 nm peaking at 344 nm and 469 nm, and exhibited an intense red emission band with a range from 600 nm to 800 nm centered around 651 nm. The optimal Mn⁴⁺ doping concentration of LMS:Mn⁴⁺ was 0.6 mol% and its internal quantum efficiency can reach as high as 83%. Besides, the thermal quenching effect on the optical property was also analyzed. Finally, a warm white light-emitting diode (WLED) lamp was fabricated by using a 454 nm InGaN blue LED chip combined with a blend of YAG:Ce³⁺ yellow phosphors and the as-prepared LMS:0.6% Mn⁴⁺ red phosphors, which showed bright white light with CIE chromaticity coordinates (0.4093, 0.3725), correlated color temperature (CCT = 3254 K), color rendering index (CRI = 81) and luminous efficacy (LE = 87 lm/W).

Mn⁴⁺-activated Li₃Mg₂SbO₆ red-emitting phosphor with internal quantum efficiency as high as 83% was developed for blue-pumped warm-white light-emitting diodes.