Modeling and admittance recursive simulation of anti-reflective coatings for photothermal conversion: synergy between subwavelength structures and gradient refractive index layers.

In the field of photothermal conversion, light-absorbing layers show limitations such as low solar energy utilization and excessive surface reflection. This paper proposes a new anti-reflective coating consisting of a gradient-doped fluorescent glass film covering a subwavelength structural layer for photothermal conversion. Its transmittance was simulated using equivalent medium theory and the admittance recursion method. The subwavelength structure provides a refractive index gradient, and its shape solves the problem of the sharp decrease in transmittance at high angles of incidence. Subsequently, we adjust the material parameters of the gradient refractive layers and control the thickness of each layer to minimize interlayer Fresnel reflections. Finally, the efficient light-trapping ability of the model was verified by calculating and comparing the transmittances of the optimized model and bare glass. Notably, within the visible spectrum, our model achieves an average transmittance of over 95% across wavelength and angle ranges, effectively suppressing surface reflections. At a larger light incident angle, the transmittance increases by 29.7%, and the minimum angle transmittance reaches 92.7%. This study proposes an innovative method to enhance the performance of transmission layers in photothermal conversion devices.

Enhancing Linearity of Light Response in Avalanche Photodiodes by Suppressing Electrode Size Effect.

The nonlinear characteristics of avalanche photodiodes (APDs) inhibit their performance in high-speed communication systems, thereby limiting their widespread application as optical detectors. Existing theoretical models have not fully elucidated complex phenomena encountered in actual device structures. In this study, actual APD structures exhibiting lower linearity than their ideal counterparts were revealed. Simulation analysis and physical inference based on GaN APDs reveal that electrode size is a noteworthy factor influencing response linearity. This discovery expands the nonlinear theory of APDs, suggesting that APD linearity can be enhanced by suppressing the electrode size effect. A physical model was developed to explain this phenomenon, which is attributed to charge accumulation at the edge of the contact layer. Therefore, we proposed an improved APD design that incorporates an additional gap layer and a buffer layer to stabilize the internal gain under high-current-density conditions, thereby enhancing linearity. Our improved APD design increases the linear threshold for optical input power by 4.46 times. This study not only refines the theoretical model for APD linearity but also opens new pathways for improving the linearity of high-speed optoelectronic detectors.

Modeling of the synergistic anti-reflection effect in gradient refractive index films integrated with subwavelength structures for photothermal conversion.

Photothermal materials generally suffer from challenges such as low photothermal conversion efficiency and inefficient full-spectrum utilization of solar energy. This paper proposes gradient refractive index transparent ceramics (GRITCs) integrated with subwavelength nanostructure arrays and simulates the synergistic anti-reflection effect by an admittance recursive model. An innovative subwavelength structure, possessing a superior light-trapping capability, is initially crafted based on this model. Subsequently, various intelligent optimization algorithms including genetic algorithm, particle swarm optimization, and simulated annealing are employed to optimize the structure of gradient refractive index films respectively. Finally, the photothermal conversion efficiencies of devices based on different photothermal materials are calculated. The simulations and finite-difference time-domain calculations demonstrate that the three-layer GRITCs integrated with an optimal SNA exhibit outstanding full-spectrum and omnidirectional anti-reflection performance. The solar transmittance of the devices can exceed 97% for light wavelengths ranging from 300 to 2500 nm over the full angle of incidence. Our results reveal that the synergistic anti-reflection effect in the SNAs and GRITCs can enhance the photothermal conversion efficiency by more than 20%.

Structures, principles, and properties of metamaterial perfect absorbers.

Metamaterials are a kind of artificial material with special properties, showing huge potential for applications in fields such as infrared measurement, solar cells, optical sensors, and optical stealth. A metamaterial perfect absorber (MPA) is designed based on a metamaterial, featuring strong absorption, small volume, light weight, ultra-bandwidth, tunability and other characteristics. This paper introduces the absorption mechanism of MPAs from microwave to optical wave band, and four directions of absorber design are elaborated. Equivalent impedance matching, plasma resonance and interference effect are the main absorption mechanisms of MPA. Multiband perfect absorption, ultra-wideband and ultra-narrowband perfect absorption, polarization and angle insensitive absorption, and dynamically controllable tunable absorption are the main design aspects. Among them, the proposal of a dynamically tunable absorber realizes the dynamic absorption. Finally, the problems and challenges of metamaterial perfect absorber design are discussed.

Flexible multicolor biaxial sensor for strain direction identification based on sandwich-structured mechanoluminescent materials.

Strain sensors capable of recognizing the direction of strain are crucial in applications such as robot attitude adjustment and detection of strain states in complex structures. In this study, a sandwich-structured flexible biaxial strain sensor was developed using polydimethylsiloxane as the substrate, mechanoluminescent materials as the luminescent elements, and rubber-ink as the light-blocking layer. By correlating the emitted light color with the stretching state, precise identification of the applied strain direction is achieved. Additionally, the mechanoluminescence of the sensor is collected by a photodiode, generating photocurrent that can be analyzed. This provides a solution for practical applications of sensor.

Effect of mindfulness-based mind-body therapies in patients with non-specific low back pain-A network meta-analysis of randomized controlled trials.

Background/objectives: Although mindfulness-based mind-body therapy (MBMBT) is an effective non-surgical treatment for patients with non-specific low back pain (NLBP), the best MBMBT mode of treatment for NLBP patients has not been identified. Therefore, a network meta-analysis (NMA) was conducted to compare the effects of different MBMBTs in the treatment of NLBP patients. Methods: PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science databases were searched for randomized controlled trials (RCTs) applying MBMBT for the treatment of NLBP patients, with all of the searches ranging from the time of database creation to January 2023. After 2 researchers independently screened the literature, extracted information, and evaluated the risks of biases in the included studies, the data were analyzed by using Stata 16.0 software. Results: A total of 46 RCTs were included, including 3,886 NLBP patients and 9 MBMBT (Yoga, Ayurvedic Massage, Pilates, Craniosacral Therapy, Meditation, Meditation + Yoga, Qigong, Tai Chi, and Dance). The results of the NMA showed that Craniosacral Therapy [surface under the cumulative ranking (SUCRA): 99.2 and 99.5%] ranked the highest in terms of improving pain and disability, followed by Other Manipulations (SUCRA: 80.6 and 90.8%) and Pilates (SUCRA: 54.5 and 71.2%). In terms of improving physical health, Craniosacral Therapy (SUCRA: 100%) ranked the highest, followed by Pilates (SUCRA: 72.3%) and Meditation (SUCRA: 55.9%). In terms of improving mental health, Craniosacral Therapy (SUCRA: 100%) ranked the highest, followed by Meditation (SUCRA: 70.7%) and Pilates (SUCRA: 63.2%). However, in terms of improving pain, physical health, and mental health, Usual Care (SUCRA: 7.0, 14.2, and 11.8%, respectively) ranked lowest. Moreover, in terms of improving disability, Dance (SUCRA: 11.3%) ranked lowest. Conclusion: This NMA shows that Craniosacral Therapy may be the most effective MBMBT in treating NLBP patients and deserves to be promoted for clinical use. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, PROSPERO [CRD42023389369].

Modeling Monte Carlo simulation on photon regeneration effects of perovskite FAPbI3 for photovoltaic applications.

Controlling the photon regeneration effects in FAPbI3 films is a noteworthy approach to improve the photovoltaic (PV) efficiency of FAPbI3-based solar cells. However, the lack of systematic study on the relationship between photon regeneration effects and PV efficiency in the experimental process makes it difficult to control the photon regeneration effects effectively. In this work, we combine the Monte Carlo sampling method and the polar coordinate calculation method to design a new algorithm for a detailed simulation of the main processes of photon regeneration effects affecting the PV efficiency in a model based on an n-i-p type FAPbI3 perovskite solar cell (PSC). The algorithm is validated to be used to compare the power-conversion efficiency (PCE) of different PSCs to filter out the PSC structure with the highest PCE or to determine the range of material parameter values corresponding to the highest PCE. This work opens up new ideas to effectively control the photon regeneration effects in PSCs to improve the device PV efficiency.

Structures, photoluminescence, and principles of self-activated phosphors.

Self-activated phosphors without any luminescent dopants, usually display excellent optical properties, such as high oscillator strength, large Stokes shift, and strong luminescence efficiency, and thus have been widely investigated by researchers for several decades. However, their recent advancements in scintillators, white-light illumination, displays and optical sensors compel us to urgently understand the basic principles and significant technological relevance of this worthy family of materials. Herein, we review the structures, photoluminescence principles, and applications of state-of-the-art self-activated phosphors, such as borate, gallate, niobate, phosphate, titanate, vanadate, tungstate, nitrides, oxyfluoride, perovskite, metal halides, and carbon dots. The photoluminescence principles of self-activated phosphors are mainly summarized as transitions between energy levels of rare-earth and transition metal ions, charge transfer transitions of some oxide compounds, and luminescence in all-inorganic semiconductors. The different self-activated phosphors exhibit various structures and site-dependent spectra. Additionally, we discuss the application prospect and main challenges of self-activated phosphors.

Effectiveness of cognitive behavioral therapy for patients after total knee arthroplasty: a systematic review and meta-analysis.

Total knee arthroplasty (TKA) is considered a common surgical option in patients with end-stage osteoarthritis of the knee. This systematic review and meta-analysis aimed to determine the effectiveness of cognitive behavioral therapy (CBT) for patients after TKA. PubMed, EMBASE, the Cochrane Library, Web of Science and CINAHL were searched for randomized controlled trials (RCTs) from inception to 20 August 2021. Included studies were evaluated with the Cochrane risk-of-bias tool. Six RCTs were included. Our study results demonstrated that a significant reduction in pain catastrophing was seen in patients receiving CBT at post-intervention (SMD -0.48, 95% CI = -0.72 to -0.23, I2 17.2%, p = 0.00) but not in 3-month or 12-month follow-up. There were no significant differences between CBT and usual-care patients regarding pain intensity or knee function at different time-points. This is the first time that meta-analysis has been conducted to determine the effectiveness of CBT for patients after TKA. It is necessary to conduct longer follow-ups, include larger samples and conduct rigorous RCTs to further explore this issue.

Pain catastrophizing and associated factors in preoperative total knee arthroplasty in Lanzhou, China: a cross-sectional study.

BACKGROUND: Pain catastrophizing in preoperative total knee arthroplasty (TKA) patients is associated with several poorly characterised factors in the literature. This study investigated the current state and associated factors of preoperative pain catastrophizing in patients undergoing TKA. METHODS: This descriptive cross-sectional study was conducted at the orthopedics ward of two tertiary hospitals in Lanzhou, China. Pain catastrophizing was measured using the Chinese versions of the Pain Catastrophizing Scale, Short Form-36 (physical function domain), Numerical Rating Scale, Oxford Knee Score, Hospital Anxiety and Depression Scale, and Life Orientation Test-Revised. RESULTS: The study included 360 participants. Preoperative TKA pain catastrophizing in all patients was high, with a mean score of 24.92 (SD: 12.38). The stepwise multiple linear regression analysis revealed anxiety (ß = 0.548, P < 0.01), education level (ß = - 0.179, P < 0.01), physical function (ß = - 0.156, P < 0.01), and pain intensity during activity (ß = 0.105, P = 0.015) as associated factors for pain catastrophizing, possibly explaining 51.2% of the total variation (F = 95.149, P < 0.01). CONCLUSION: Anxiety was the most relevant factor for pain catastrophizing in patients with preoperative TKA. Lower education levels, poor physical function, and stronger pain intensity during the activity were also associated with pain catastrophizing.

The feasibility and safety of cocktail treatment of triple anti-inflammatory agents loaded with gelatin sponge promotes early recovery after posterior percutaneous endoscopic cervical discectomy.

PURPOSE: To investigate whether a cocktail therapy of dexamethasone, ropivacaine, dexmedetomidine, and vitamin B12 can achieve satisfactory pain relief and promote early functional recovery after PPECD. METHODS: Eighty single-level patients with CDH who received PPECD were retrospectively divided into two groups: the cocktail and control groups. Clinical data were recorded and evaluated by a dedicated physician who was not involved in the patient's treatment. The primary clinical outcomes included visual analog scores (VASs) for upper limber pain and neck disability index (NDI) scores. The follow-up time points were preoperatively and postoperative 1 week, 1 month, 3 months, 6 months, and 12 months. The modified MacNab criteria was used to evaluate the surgical effect of the last follow-up. RESULTS: The follow-up data of 74 cases were complete, except 6 cases lost to follow-up. There was no significant difference between the two groups in demographics, duration of symptoms, operation stage (p > 0.05), and operation time (80.5 ± 5.5 vs. 81.5 ± 3.5 min). The VAS in the upper limbs pain was significantly higher postoperatively than preoperatively in both groups (p < 0.05). The cocktail group had a lower VAS than the control group 1 week postoperatively (p < 0.05); however, VAS not different between groups at the remaining time points. The NDI scores were significantly better postoperatively than preoperatively, and no significant differences were seen when comparing nodes at postoperative follow-up (p > 0.05). In the control group, two cases with foraminal stenosis were found to have unrelieved pain in the early postoperative period, but the pain was relieved at the final follow-up and did not convert to open decompression surgery. CONCLUSIONS: Cocktail treatment, in which a drug sustained-release material made of gelatin sponge was impregnated with dexamethasone, ropivacaine, dexmedetomidine and vitamin B12, facilitates pain relief and early postoperative recovery after PPECD.

Magnesene: a theoretical prediction of a metallic, fast, high-capacity, and reversible anode material for sodium-ion batteries.

Sodium-ion batteries (SIBs) have attracted great attention owing to their low cost and inherent safety. High-performance anode materials for SIBs should possess intrinsically metallic characteristic and be composed of non-toxic, earth abundant, and lightweight elements. We predict a two-dimensional Mg material (named magnesene) to be an excellent anode material, which can meet these design requirements. It is demonstrated to be stable in terms of the cohesive energy, phonon spectrum, ab initio molecular dynamics simulation, and elastic constants. The magnesene monolayer exhibits good SIB performances, including a high storage capacity of 551.3 mA h g-1, low diffusion energy barrier (0.16-0.19 eV), low open-circuit voltage (0.71-0.82 V), and small volume change (4.7%). Moreover, graphene or h-BN on top of magnesene could serve as a protective cover to preserve the performances of pristine magnesene, such as metallicity, strong Na adsorption capability, and fast ionic mobility. These intriguing theoretical findings make magnesene a promising anode material for SIBs.

Endo-TLIF versus MIS-TLIF in 1-segment lumbar spondylolisthesis: A prospective randomized pilot study.

OBJECTIVE: To evaluate the curative efficacy by comparing perioperative characteristics and 1.5-year observational outcomes in 1-segment lumbar spondylolisthesis between traditional minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and optimized Endoscopic TLIF techniques. METHODS: The study was a single-center, randomized controlled trial comparing two different treatment approaches for 1-segment lumbar spondylolisthesis. 102 patients treated by MIS-TLIF (48 cases) or Endo-TLIF (54 cases) were included from March 2018 to April 2019. Perioperative parameters and clinical outcomes were evaluated. Degree of slip were measured, and fusion rates were determined at 18 months after surgery. RESULTS: The Endo-TLIF group had similar return to work time and rate. Blood loss, left bed time, analgesic ratio were significantly less in Endo-TLIF group. The Endo-TLIF group had a significantly longer operative time. Significant postoperative reduction in %slip was showed in both groups. The VAS and ODI improved significantly in both groups after surgery. Significant decreases in low-back pain in Endo-TLIF group were found at postoperative day 1 and 3 months. The fusion rate in the two groups was similar. CONCLUSION: Endo-TLIF surgery with a C-shaped working tube and a visualization system may be regarded as an efficient alternative surgery for 1-segment lumbar spondylolisthesis. It is a safe and minimally invasive way to perform this surgery and has shown satisfactory clinical outcomes. TRIAL REGISTRATION: ChiCTR1800015197, 13 March 2018. TRIAL REGISTRY: Chinese Clinical Trial Registry. Registered 13 March 2018. http://www.chictr.org.cn/showproj.aspx?proj=25865.

Structures, plasmon-enhanced luminescence, and applications of heterostructure phosphors.

Heterostructure phosphor composites have been used widely in the fields of targeted bio-probes and bio-imaging, hyperthermia treatment, photocatalysis, solar cells, and fingerprint identification. The structures, plasmon-enhanced luminescence and mechanism of metal/fluorophore heterostructure composites, such as core-shell nanocrystals, multilayers, adhesion, islands, arrays, and composite optical glass, are reviewed in detail. Their extended applications were explored widely since the surface plasmon resonance effect increased the up-conversion efficiency of fluorophores significantly. We summarize their synthesis methods, size and shape control, absorption and excitation spectra, plasmon-enhanced up-conversion luminescence, and specific applications. The most important results acquired in each case are summarized, and the main challenges that need to be overcome are discussed.

Can Additional Facet Joint Block Improve the Clinical Outcome of Kyphoplasty for Acute Osteoporotic Vertebral Compression Fractures?

BACKGROUND: Percutaneous kyphoplasty (PKP) has been reported to provide a favorable analgesic effect for pain caused by osteoporotic vertebral compression fractures (OVCFs). However, a systematic review demonstrated that pain relief was only reported for approximately 86% of kyphoplasty treatments. OBJECTIVES: To explore whether an additional facet joint block (FJB) can minimize pain and improve the clinical outcome of PKP in patients with acute OVCFs. STUDY DESIGN: Prospective study. SETTING: All data were from Honghui Hospital in Xi'an. METHODS: According to the inclusion and exclusion criteria, 194 patients were eventually included in our study; they were randomly divided into 2 groups of 97 patients each and treated with either PKP + FJB or PKP alone. Follow-up consultations were scheduled 1 day, 3 days, 1 week, 1 month, 3 months, and 1 year postoperatively; the demographic characteristics, related surgical information, and complications observed within both groups were recorded. The clinical evaluation parameters included the intraoperative satisfaction score, the Visual Analog Scale (VAS) score, and the Oswestry Disability Index (ODI). RESULTS: A total of 171 patients (61 men and 110 women; age range: 62-85 years) completed the full postoperative follow-up schedule, with 83 patients in the PKP + FJB group and 88 in the PKP group. No significant differences were observed in the genders, ages, preoperative bone mineral density, surgical levels, or volume of cement injected between the 2 groups (P > 0.05, respectively). The average duration of the surgeries in the PKP + FJB group was slightly longer than that in the PKP group (35.5 ± 4.8 min vs. 31.8 ± 4.3 min; P = 0.038), and in terms of the clinical outcomes, the average intraoperative satisfaction score was significantly higher in the PKP + FJB group (8.6 ± 1.1 vs. 6.3 ± 1.3; P < 0.001). Compared with the preoperative data, significant improvements in the VAS scores of back pain and ODI were observed at each follow-up interval (P < 0.05, respectively). These scores were significantly higher in the PKP + FJB group than in the PKP group; however, this was only observed within the first month after the procedure. LIMITATIONS: A single-center noncontrol study. CONCLUSIONS: The addition of an FJB (which in our study involved a unique combination of ropivacaine, prednisolone, and vitamin B12) improved the short-term clinical outcome of PKP for acute OVCFs. The local anti-inflammatory and analgesic effects on the facet joints resulted in higher intraoperative satisfaction and lower VAS and ODI scores for the first postoperative month when compared with the PKP group.

[Treatment of senile lumbar spinal stenosis by unilateral approach and bilateral decompression with large channel endoscopy].

OBJECTIVE: To evaluate clinical effect of unilateral approach and bilateral decompression via large channel endoscopic system for the treatment of lumbar spinal stenosis. METHODS: The clinical data of 32 patients with lumbar spinal tenosis treated by unilateral approach and bilateral decompression via large channel endoscopy from February 2018 to February 2019 were retrospectively analyzed. There were 18 males and 14 females, aged 65 to 84 years old with an average of (70.6± 8.4) years. The course of disease was from 1 to 12 years. All 32 cases were accompanied by numbness or pain in the lower limbs, of which 28 cases were accompanied by intermittent claudication. Narrow segments were L3, 4 of 2 cases, L4, 5 of 19 cases, L5S1 of 13 cases, including double segments of 2 cases. Preoperative imaging showed 3 cases of central canal stenosis, 21 cases of bilateral lateral recess stenosis and 8 cases of mixed stenosis. Operation time and complications were recorded. X-ray, CT and MRI were analyzed at 3 days, 3 months and 1 year after operation. Visual analogue scale(VAS), Oswestry Disability Index (ODI), single continuous walking distance(SCWD) were observed before and after operation. Modified Macnab standard were used to evaluate the clinical effect at 1 year after operation. RESULTS: All the patients were followed up for 12-24 (17.68±2.43) months and all operations were successfully completed with the operation time of 70-160(85.64±11.94) min. Spinal dural tear occurred in 1 case during the operation, and sensory disturbance in the other side of lower limb in a short period of time occurred in 2 cases, all improved after corresponding treatment. Postoperative imaging showed that the spinal canal was significantly enlarged and the nerve root was fully released. Before operation and 3 days, 3 months, 1 year after operation, VAS scores of low back pain were 4.62 ±1.41, 2.73 ±1.35, 1.21 ±1.17, 1.11 ±0.34, respectively;VAS scores of leg pain were 6.83 ± 1.71, 3.10±1.50, 1.08±0.19, 0.89±0.24, respectively. VAS scores of low back pain and leg pain each time point after operation were obvious improved (P<0.05); there was significant difference between 3 months and 3 days after operation(P<0.05), and there was no significant difference between 3 months and 1 year after operation (P>0.05). Before operation and 3 days, 3 months, 1 year after operation, ODI scores were 38.40 ±6.48, 18.42 ±2.40, 5.48 ±0.77, 3.05 ±0.28, respectively; SCWD was (47.48±5.32) m, (52.89±11.23) m, (245.43±18.94) m, (468.97±55.87) m, respectively. The differences in ODI score and SCWD postoperative time points were statistically significant compared with those before operation (P<0.05). The difference between 3 months and 3 days after operation was statistically significant (P<0.05). The difference between 1 year and 3 months after operation was statistically significant (P<0.05). According to Macnab standard to evaluate clinical effect at 1 year after operation, 15 cases got excellent results, 14 good, 3 fair. CONCLUSION: It is a safe and effective way to treat lumbar spinal stenosis with unilateral approach and bilateral decompression via large channel endoscopic system. It has the advantages of sufficient decompression, less trauma, fast recovery, high safety and low incidence of postoperative complications. It can minimize the damage to the stable structure of the lumbar spine and is an ideal minimally invasive operation for the treatment of lumbar spinal stenosis.

Monte Carlo simulation and experimental evaluation of the quantum efficiency of Eu3+-doped glass at different temperatures.

The quantum efficiency (QE) is a key parameter to evaluate the optical properties of fluorescent glass. However, it is very difficult to measure the QE at high temperatures by the integrating sphere test system. In this paper, we report a new method to calculate the QE of five kinds of Eu3+-doped glasses at different temperatures based on experimental absorption and excitation spectra of Eu3+-doped glasses. The simulated QE values agree well with the experimental values of QE. Furthermore, the influence of the shape, refractive index and temperature on the QE and the spatial light intensity distribution of the Eu3+-doped glass is studied based on the Monte Carlo method. This work presents a simple method to calculate the QE and the spatial light intensity distribution at different temperatures.

Posterior percutaneous endoscopic versus traditional surgery for cervical disc herniation: A protocol for systematic review and meta analysis.

BACKGROUND: Posterior percutaneous endoscopic cervical diskectomy (P-PECD) can be used posterior microdiscectomy for cervical disc herniation. But only some small sample sizes of clinical studies have evaluated the efficacy and safety of P-PECD. This study aim to evaluated the efficacy and safety of P-PECD compared with traditional open surgery. METHODS: We will search the following seven electronic databases from their initiation to the May 1, 2020: PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature Database (CBM) and Wanfang database. All randomized controlled trials, non-randomized controlled trials and retrospective case controls that compared the efficacy and safety of P-PECD and traditional open surgery in the treatment of cervical disc herniation will be included. The pooled odds ratio with 95% credible intervals (CIs) was used for the dichotomous variables. The mean difference with 95% CIs was used for the continuous variables. All analyses were conducted by Comprehensive Meta Analysis 2.0. A 2-tailed P value < 0.05 is considered statistically significant. RESULTS: The results of systematic review and meta-analysis will be submitted to a peer-reviewed journal. CONCLUSION: Our study will provide clarity regarding for clinicians to choices best surgical approach for patients with cervical disc herniation. Any changes that need to be made during the process of this study will be explained in the final full-text publication. PROTOCOL REGISTRATION NUMBER: CRD42020164011.

Effect of light scattering on upconversion photoluminescence quantum yield in microscale-to-nanoscale materials.

Scattering affects excitation power density, penetration depth and upconversion emission self-absorption, resulting in particle size -dependent modifications of the external photoluminescence quantum yield (ePLQY) and net emission. Micron-size NaYF4:Yb3+, Er3+ encapsulated phosphors (∼4.2 µm) showed ePLQY enhancements of >402%, with particle-media refractive index disparity (Δn): 0.4969, and net emission increases of >70%. In sub-micron phosphor encapsulants (∼406 nm), self-absorption limited ePLQY and emission as particle concentration increases, while appearing negligible in nanoparticle dispersions (∼31.8 nm). These dependencies are important for standardising PLQY measurements and optimising UC devices, since the encapsulant can drastically enhance UC emission.

Comparison of Clinical and Radiologic Outcome Between Mini-Open Wiltse Approach and Fluoroscopic-Guided Percutaneous Pedicle Screw Placement: A Randomized Controlled Trial.

OBJECTIVE: To compare clinical efficacy, radiographic outcome, and radiation exposure between mini-open pedicle screw (MPS) fixation with the Wiltse approach and percutaneous pedicle screw (PPS) fixation in treatment of young and middle-aged patients with thoracolumbar burst fractures. METHODS: Of 60 patients with thoracolumbar vertebrae fractures treated in our hospital from January 2017 to January 2018, 30 were randomly assigned to the MPS group and 30 were randomly assigned to the PPS group. Clinical efficacy, radiographic outcome, and radiation exposure were compared between the 2 groups. RESULTS: The average age of patients was 42.2 ± 6.7 years in the MPS group and 43.0 ± 6.9 years in the PPS group (P = 0.668). There was no significant difference between the 2 groups in blood loss, hospital stay, postoperative visual analog scale score for back pain, and Oswestry Disability Index score. The vertebral body height and vertebral body angle of the MPS group were significantly better than those of the PPS group at the last follow-up. There was no significant difference in the accuracy rate of pedicle screw placement between the MPS group and the PPS group; the facet joint violation was significantly higher in the PPS group. The average radiation exposure dosage was lower in the MPS group. CONCLUSIONS: Both MPS fixation with the Wiltse approach and PPS fixation are safe and effective in the treatment of single-segment thoracolumbar vertebral fractures. Nevertheless, considering the surgical duration, radiation exposure, facet joint violation, vertebral body height, and vertebral body angle at the last follow-up, MPS fixation with the Wiltse approach is a better choice than PPS.