Inserting colloidal quantum dots into GaN mesa-array subsurface porous structures through electrochemical etching for display color conversion application.

High-efficiency photon color conversion is an approach of great potential for implementing color display. Inspired by the observation of emission enhancement in a nanoscale cavity, a novel technique to fabricate an array of color converter by mixing colloidal quantum dots (QDs) with the electrolyte of an electrochemical etching (ECE) process is demonstrated. In this process, QDs flow with the electrolyte into the etched subsurface nanoscale porous structure (PS) and settle inside. Since the PS formation and hence QD insertion are controlled by the flow path of the applied electric current in the ECE process, this technique can be used for fabricating any graphic pattern. The nanostructure of such a QD-inserted mesa is examined to confirm QD insertion. Although only single-color mesa arrays are demonstrated in this paper, this technique can be used for fabricating a multiple-color mesa array if a QD or a light-emitting nanoparticle of higher thermal stability is available.

Improving the detection of hypo-vascular liver metastases in multiphase contrast-enhanced CT with slice thickness less than 5 mm using DenseNet.

INTRODUCTION: Thinner slices are more susceptible in detecting small lesions but suffer from higher statistical fluctuation. This work aimed to reduce image noise in multiphase contrast-enhanced CT reconstructed with slice thickness thinner than the clinical setting (i.e., 5 mm) using convolutional neural network (CNN) for enabling better detection of hypo-vascular liver metastasis. METHODS: A DenseNet model was used to generate noise map for multiphase CT reconstructed with slice thickness of 2.5 mm and 1.25 mm. Image denoising was conducted by subtracting the CNN-generated noise map from CT images with reduced photon flux due to thinner slice thickness. The performance of DenseNet was evaluated on CT scans of electron density phantoms and patients with hypovascular liver metastases less than 1.5 cm in terms of Hounsfield Unit (HU) variation, statistical fluctuation, and contrast-to-noise ratio (CNR). RESULTS: The phantom study demonstrated that the CNN-based denoising method was able to reduce statistical fluctuation in CT images reconstructed with slice thickness of 2.5 mm and 1.25 mm without causing significant edge blurring or variation in HU values. With regards to patient study, it was found that the denoised 2.5-mm and 1.25-mm slices had higher CNR than the conventional 5-mm slices for hypo-vascular liver metastases in all 4 phases of multiphase CT. CONCLUSION: Our results demonstrated that the detection of hypo-vascular liver metastases in multiphase contrast-enhanced CT with slice thickness less than 5 mm could be improved by using the CNN-based denoising method. IMPLICATIONS FOR PRACTICE: Reconstruction slice thickness has a strong influence on the image quality of CT imaging. A CNN-based denoising method was used in this work to reduce the image noise in multiphase contrast-enhanced CT reconstructed with slice thickness less than 5 mm.

Surface plasmon coupling effects on the photon color conversion behaviors of colloidal quantum dots in a GaN nanoscale hole with a nearby quantum-well structure.

To improve color conversion performance for color display application, we study the near-field-induced nanoscale-cavity effects on the emission efficiency and Förster resonance energy transfer (FRET) under the condition of surface plasmon (SP) coupling by inserting colloidal quantum dots (QDs) and synthesized Ag nanoparticles (NPs) into surface nano-holes fabricated on a GaN template and an InGaN/GaN quantum-well (QW) template. In the QW template, the inserted Ag NPs are close to either QWs or QDs for producing three-body SP coupling to enhance color conversion. Time-resolved and continuous-wave photoluminescence (PL) behaviors of the QW- and QD-emitting lights are investigated. The comparison between the nano-hole samples and the reference samples of surface QD/Ag NP shows that the nanoscale-cavity effect of the nano-hole leads to the enhancements of QD emission, FRET between QDs, and FRET from QW into QD. The SP coupling induced by the inserted Ag NPs can enhance the QD emission and FRET from QW into QD. Its result is further enhanced through the nanoscale-cavity effect. The relative continuous-wave PL intensities among different color components also show the similar behaviors. By introducing SP coupling to a color conversion device with the FRET process in a nanoscale cavity structure, we can significantly improve the color conversion efficiency. Simulation results confirm the basic observations in experiment.

Photon color conversion enhancement of colloidal quantum dots inserted into a subsurface laterally-extended GaN nano-porous structure in an InGaN/GaN quantum-well template.

To improve the color conversion performance, we study the nanoscale-cavity effects on the emission efficiency of a colloidal quantum dot (QD) and the Förster resonance energy transfer (FRET) from quantum well (QW) into QD in a GaN porous structure (PS). For this study, we insert green-emitting QD (GQD) and red-emitting QD (RQD) into the fabricated PSs in a GaN template and a blue-emitting QW template, and investigate the behaviors of the photoluminescence (PL) decay times and the intensity ratios of blue, green, and red lights. In the PS samples fabricated on the GaN template, we observe the efficiency enhancements of QD emission and the FRET from GQD into RQD, when compared with the samples of surface QDs, which is attributed to the nanoscale-cavity effect. In the PS samples fabricated on the QW template, the FRET from QW into QD is also enhanced. The enhanced FRET and QD emission efficiencies in a PS result in an improved color conversion performance. Because of the anisotropic PS in the sample surface plane, the polarization dependencies of QD emission and FRET are observed.

[Role of inducible costimulatory molecules (ICOS) and related cytokines in immune regulation of Echinococcus granulosus infections in mice].

OBJECTIVE: To investigate the roles of inducible costimulatory molecules (ICOS) and related cytokines in the immune regulation of Echinococcus granulosus infections in mice. METHODS: Eighty BALB/c mice (weight 18-22 g) were divided into the control and infection groups, of 40 animals in each group. E. granulosus infection was modeled in mice by intraperitoneal injection of 10 000 protoscoleces per mouse. Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) and peripheral interleukin-4 (IL-4) and IL-10 levels were measured 2, 8, 30, 60, 180 days post-infection. Mouse liver specimens were excised for hematoxylin-eosin (HE) staining and immunostaining, and ICOS expression was quantified in mouse liver specimens using quantitative real-time PCR (qPCR) assay. RESULTS: There were no significant differences in serum ALT (F = 12.082, P < 0.05), AST (F = 6.347, P < 0.05) or ALP levels (F = 52.186, P < 0.05) in mice 2, 8, 30, 60 and 180 days post-infection with E. granulosus. The serum ALT levels were significantly higher in the infection group than in the control group 2 [(61.72 ± 9.89) vs. (50.65 ± 4.67)U/L, P < 0.05] and 30 days post-infection [(80.61 ± 23.71)vs.(67.75 ± 9.79)U/L, P < 0.05], and the serum ALT levels were significantly higher in the infection group than in the control group 2 [(181.06 ± 60.61) vs.(115.58 ± 17.66)U/L, P < 0.05] and 180 days post-infection [(137.84 ± 29.01) vs. (108.05 ± 10.33) U/L, P < 0.05], while greater serum ALP levels were measured in the infection group than in the control group 2 [(162.90 ± 21.04)vs.(64.54 ± 5.99)U/L, P < 0.05], 8[(176.36 ± 24.56) vs. (62.70 ± 9.21)U/L, P < 0.05] and 30 days post-infection [(138.86 ± 13.59) vs. (58.60 ± 5.28) U/L, P < 0.05]. A few inflammatory cells were seen in mouse liver in the infection group 30 days post-infection, and no apparent changes were found in the mouse hepatic structure 60 days post-infection. On day 180 post-infection, a large number of epithelium-like cells presented fibrotic growth in mouse liver in the cyst-infiltrating regions, with cuticula formation seen, and plenty of red cells were present in lesions and hepatocyte space. Positive ICOS expression was detected in mouse liver in the infection group, with ICOS-positive cells predominantly seen in the cytoplasm of the hepatocyte, and the ICOS expression increased over time. The relative ICOS mRNA expression was 2.732 ± 0.094 on day 180 post-infection, which was significantly greater than that on day 2 postinfection (0.746 ± 0.049). There were no significant differences in serum IL-4 or IL-10 levels at different time points after E. granulosus infections, while the serum IL-4 and IL-10 levels peaked in the infection group 180 days and 60 days post-infection, respectively. Higher serum IL-4 levels were measured in the infection group than in the control group 8 [(22.50 ± 3.24) vs. (5.82 ± 0.49) pg/mL, P < 0.05], 30 [(15.49 ± 4.73) vs. (5.10 ± 1.38) pg/mL, P < 0.05], 60 [(36.93 ± 6.14) vs. (4.13 ± 1.19) pg/mL, P < 0.05] and 180 days post-infection [(198.35 ± 0.70) vs. (4.19 ± 0.98) pg/mL, P < 0.05], and higher IL-10 levels were measured in the infection group than in the control group 2 [(4.84 ± 1.91) vs. (2.11 ± 1.03) pg/mL, P < 0.05], 8 [(44.72 ± 14.63) vs. (3.16 ± 0.60) pg/mL, P < 0.05], 30 [(25.47 ± 8.00) vs. (3.83 ± 1.87) pg/mL, P < 0.05], 60 [(187.16 ± 60.44) vs. (3.69 ± 1.05) pg/mL, P < 0.05] and 180 days post-infection [(85.40 ± 7.15) vs. (3.25 ± 0.93) pg/mL, P < 0.05]. CONCLUSIONS: High ICOS expression is present in the liver of mice with E. granulosus infections. The positive ICOS expression and immune activation levels increase with the time of E. granulosus infections, leading to aggravation of hepatocyte injury caused by inflammation.

Enhancing deep-UV emission at 234 nm by introducing a truncated pyramid AlN/GaN nanostructure with fine-tuned multiple facets.

The external quantum efficiency of a high-Al content (>0.6) AlGaN deep-ultraviolet (DUV) light-emitting diode is typically below 1% in the sub-250 nm wavelength range. One of the main reasons for this low efficiency is the fundamental properties of high-Al content AlGaN comprising the transverse-magnetic (TM)-dominant emission and low light extraction due to the total internal reflection (TIR). This work demonstrates a truncated pyramid nanostructure with fine-tuned multiple facets in an (AlN)8/(GaN)2 digital alloy to achieve highly efficient DUV emission at 234 nm. By applying nanoimprint lithography, dry and wet etching, a hexagonal truncated pyramid nanohole structure is fabricated featuring multiple crystal facets of (0001), (10-13), and (20-21) planes. These fine-tuned multiple facets act as reflecting mirrors that can effectively modulate the light propagation and extraction patterns to overcome the TIR via multiple reflections and enhanced scattering. Consequently, significant light extraction enhancements of 5.6 times and 1.1 times for TM and transverse-electric emissions are achieved in the truncated pyramid nanohole structure, respectively. The total luminous intensity of this unique nanostructure is greatly increased by 191% compared to that of a conventional planar structure. The truncated pyramid AlN/GaN nanostructure with fine-tuned multiple facets used in this work provides a promising approach for realizing highly efficient sub-250 nm DUV light-emitting devices.

Mesh size control in forming an Ag/AgO nano-network structure for transparent conducting application.

The variation behaviors of the morphology, transmission, and sheet resistance of the surface Ag/AgO nano-network (NNW) structures fabricated under different illumination conditions and with different Ag deposition thicknesses and thermal annealing temperatures in forming initial Ag nanoparticles (NPs) are studied. Generally, an NNW structure with a smaller mesh size or a denser branch distribution has a lower transmission and a lower sheet resistance level. Under the fabrication condition of a broader illumination spectrum, a lower thermal annealing temperature, or a thicker Ag deposition, we can obtain an NNW structure of a smaller mesh size. The mesh size of an NNW structure is basically controlled by the seed density of Brownian tree (BT) at the beginning of light illumination. A BT seed can be formed through a stronger local localized surface plasmon resonance for accelerating Ag oxidation in a certain region. Once an Ag/AgO BT seed is formed, the surrounding Ag NPs are reorganized to form the branches of a BT. Multiple BTs are connected to form a large-area NNW structure, which can serve as a transparent conductor. Under the fabrication conditions of a broader illumination spectrum, 3 nm Ag deposition, and 100 °C thermal annealing, we can implement an NNW structure to achieve ∼1.15µm in mesh size, ∼90 Ω sq-1in sheet resistance, and 93%-77% in transmittance within the wavelength range between 370 and 700 nm.

Improvement of p-Type AlGaN Conductivity with an Alternating Mg-Doped/Un-Doped AlGaN Layer Structure.

Using molecular beam epitaxy, we prepared seven p-type AlGaN samples of ~25% in Al content, including six samples with Mg-doped/un-doped AlGaN alternating-layer structures of different layer-thickness combinations, for comparing their p-type performances. Lower sheet resistance and higher effective hole mobility are obtained in a layer-structured sample, when compared with the reference sample of uniform Mg doping. The improved p-type performance in a layer-structured sample is attributed to the diffusion of holes generated in an Mg-doped layer into the neighboring un-doped layers, in which hole mobility is significantly higher because of weak ionized impurity scattering. Among the layer-structured samples, that of 6/4 nm in Mg-doped/un-doped thickness results in the lowest sheet resistance (the highest effective hole mobility), which is 4.83 times lower (4.57 times higher) when compared with the sample of uniform doping. The effects of the Mg-doped/un-doped layer structure on p-type performance in AlGaN and GaN are compared.

Surface plasmon coupling effects on the förster resonance energy transfer from quantum dot into rhodamine 6G.

Rhodamine 6G (R6G) molecules linked CdZnSeS/ZnS green-emitting quantum dots (QDs) are self-assembled onto Ag nanoparticles (NPs) for studying the surface plasmon (SP) coupling effect on the Förster resonance energy transfer (FRET) process from QD into R6G. SP coupling can enhance the emission efficiency of QD such that FRET has to compete with QD emission for transferring energy into R6G. It is found that FRET efficiency is reduced under the SP coupling condition. Although R6G emission efficiency can also be enhanced through SP coupling when it is directly linked onto Ag NP, the enhancement decreases when R6G is linked onto QD and then the QD-R6G complex is self-assembled onto Ag NP. In particular, R6G emission efficiency can be reduced through SP coupling when the number of R6G molecules linked onto a QD is high. A rate-equation model is built for resembling the measured photoluminescence decay profiles and providing us with more detailed explanations for the observed FRET and SP coupling behaviors.

Förster resonance energy transfer in surface plasmon coupled color conversion processes of colloidal quantum dots.

Förster resonance energy transfer (FRET) from a green-emitting quantum dot (GQD) into a red-emitting quantum dot (RQD) is an important mechanism in a multiple-color conversion process, particularly under the surface plasmon (SP) coupling condition for enhancing color conversion efficiency. Here, the dependencies of FRET efficiency on the relative concentrations of GQD and RQD in their mixtures and their surface molecule coatings for controlling surface charges are studied. Also, the SP coupling effects induced by two kinds of Ag nanoparticles on the emission behaviors of GQD and RQD are demonstrated, particularly when FRET is involved in the coupling process. FRET efficiency is reduced under the SP coupling condition. SP coupling can enhance the color conversion efficiency of either GQD or RQD. The combination of SP coupling and FRET can be used for controlling the relative converted light intensities in a multiple-color conversion process.

Combined effects of surface plasmon coupling and Förster resonance energy transfer on the light color conversion behaviors of colloidal quantum dots on an InGaN/GaN quantum-well nanodisk structure.

By forming nanodisk (ND) structures on a blue-emitting InGaN/GaN quantum-well (QW) template, the QWs become close to the red-emitting quantum dots (QDs) and Ag nanoparticles (NPs) attached onto the sidewalls of the NDs such that Förster resonance energy transfer (FRET) and surface plasmon (SP) coupling can occur to enhance the efficiency of blue-to-red color conversion. With a larger ND height, more QWs are exposed to open air on the sidewall for more QD/Ag NP attachment through QD self-assembly and Ag NP drop casting such that the FRET and SP coupling effects, and hence the color conversion efficiency can be enhanced. A stronger FRET process leads to a longer QD photoluminescence (PL) decay time and a shorter QW PL decay time. It is shown that SP coupling can enhance the FRET efficiency.

Prognostic Impact of Delirium in Older People With/Without Dementia: A Retrospective Cohort Study in Taiwan.

OBJECTIVES: To elucidate the hypothetically different interactions between delirium and post-discharge prognostic indicators in elderly hospital inpatients with versus without dementia. DESIGN: Retrospective cohort study of claims data by Taiwan National Health Insurance beneficiaries between 2002-2013. SETTING: Records of public hospital admissions in the Taiwan National Health Insurance Research database. PARTICIPANTS: Propensity-score matched subgroups of patients with delirium superimposed on dementia (n = 922) versus dementia alone (n = 922), delirium alone (n = 680) versus neither delirium nor dementia (n = 680). MEASUREMENTS: Mortality, emergency department visits, readmissions, and psychotropic drug use, within 30, 180, and 365 days of discharge, were analyzed using multivariate proportional hazards or logistic regression analyses. RESULTS: Delirium superimposed on dementia was not associated with increased post-discharge mortality, or emergency department visits, but significantly increased the risk of readmissions at 365-day follow-up (adjusted HR, 95% CI: 1.26, 1.01-1.56). However, delirium without dementia was significantly associated with increased post-discharge mortality, emergency department visits and readmissions at 180 days and 365 days (respective adjusted HRs: mortality, 1.63 and 1.79; adjusted ORs: emergency department visits, 1.89 and 1.81; readmissions, 1.47 and 1.53). Delirium in patients both with dementia and without, was associated with six-fold higher likelihood of in-hospital psychotropic drug use, and doubled post-discharge psychotropic drug usage. CONCLUSIONS: The obvious association between in-hospital delirium and worsened long-term prognosis, irrespective of dementia, raises awareness to warrants proactive and multimodal prevention and intervention strategies. Furthermore, the mechanisms about different influence of delirium for patients with/without dementia need to be further explored.

A case of GNE myopathy mimicking hereditary motor neuropathy.

A 36-year-old woman who presented with upper limb distal weakness since the age of 15 years, with gradual progression to the lower limbs, is reported. Hereditary motor neuropathy was initially suspected based on distal weakness and hyporeflexia; however, whole exome sequencing accidentally revealed a compound heterozygous variant in the GNE gene, and ultrasound revealed increased homogeneous echogenicity in the involved muscles, which is characteristic of myopathic changes. Muscle magnetic resonance imaging revealed fatty infiltration in all limb muscles, sparing the triceps brachii, vastus lateralis and vastus medialis. Muscle biopsy revealed intracytoplasmic rimmed vacuole, supporting the diagnosis of GNE myopathy.

Correlation between Obstructive Sleep Apnea and Non-Alcoholic Fatty Liver Disease before and after Metabolic Bariatric Surgery.

BACKGROUND: Emerging evidence has revealed that obstructive sleep apnea (OSA) is associated with non-alcoholic fatty liver disease (NAFLD). However, the impact of OSA on NAFLD among obese patients undergoing metabolic and bariatric surgery (MBS), especially during follow-up period, remains unclear. OBJECTIVE: To analyze the correlation based on preoperative characteristics and postoperative conditions among bariatric patients with comorbid OSA and NAFLD. METHODS: Clinical data of patients who underwent MBS in our institution between January 2016 and June 2019 were reviewed retrospectively. Correlation analysis and linear regressions were used to identify how OSA links with NAFLD before and after treatment of MBS. RESULTS: Of 308 patients, 181 were diagnosed with OSA and enrolled in the present study, and 127 completed follow-up visits at 6 months. The proportion of NAFLD in the mild-moderate OSA and severe OSA groups was 75.0% and 96.0%, respectively. MBS was effective at improving sleep apnea and nocturnal hypoxia, as well as liver steatosis and fibrosis (P < 0.05). And we also found that there were significant correlations not only between OSA- and NAFLD-related characteristics at baseline but also between their improvements after surgery, eventually leading to similar prognosis of NAFLD for both groups (P < 0.05), no matter what presurgical differences existed. In addition, the results of the univariate and multivariate linear regression analyses supported preoperative liver/spleen Hounsfield units ratio (LSR) by computerized tomography (CT) as an independent predictor of the effect of MBS on liver steatosis. CONCLUSION: In conclusion, MBS plays a pivotal role in the control of medical conditions in obese patients with OSA and NAFLD. Given the correlation between OSA and NAFLD in the present study, in the case of both the severity at baseline as well as the improvement after surgery, OSA may pose an impact on the prognosis of NAFLD in bariatric patients.

Important role of surface plasmon coupling with the quantum wells in a surface plasmon enhanced color-converting structure of colloidal quantum dots on quantum wells.

To improve the color-conversion efficiency based on a quantum-well (QW) light-emitting diode (LED), a more energy-saving strategy is needed to increase the energy transfer efficiency from the electrical input power of the LED into the emission of over-coated color-converter, not just from LED emission into converted light. In this regard, the efficiency of energy transfer of any mechanism from LED QW into the color-converter is an important issue. By overlaying blue-emitting QW structures and GaN templates with both deposited metal nanoparticles (DMNPs) and color-converting quantum dot (QD) linked synthesized metal nanoparticles (SMNPs) of different localized surface plasmon (LSP) resonance wavelengths for producing multiple surface plasmon (SP) coupling mechanisms with the QW and QD, we study the enhancement variations of their internal quantum efficiencies and photoluminescence decay times. By comparing the QD emission efficiencies between the samples with and without QW, one can observe the advantageous effect of QW coupling with LSP resonances on QD emission efficiency. Also, with the LSP resonance wavelengths of both DMNPs and SMNPs close to the QW emission wavelength for producing strong SP coupling with the QW and hence QD absorption, a higher QD emission or color-conversion efficiency can be obtained.

Spatial range of the plasmonic Dicke effect in an InGaN/GaN multiple quantum well structure.

The plasmonic Dicke effect means a cooperative emission mechanism of multiple light emitters when they are simultaneously coupled with the same surface plasmon (SP) mode of a metal nanostructure to achieve a higher collective emission efficiency. Here, we compare the enhancements of emission efficiency among a series of SP-coupled InGaN/GaN quantum-well (QW) structures of different QW period numbers to show an emission behavior consistent with the plasmonic Dicke effect. The relative enhancement of overall emission efficiency increases with QW period number until it reaches a critical value, beyond which the enhancement starts to decrease. This critical QW period number corresponds to the effective depth range of the plasmonic Dicke effect in a multiple-QW system. It also represents an optimized QW structure for maximizing the SP coupling effect. Internal quantum efficiency and time-resolved photoluminescence are measured for comparing the enhanced emission efficiencies of blue and green QW structures with different QW period numbers through SP coupling induced by surface Ag nanoparticles.

Theoretical analysis of a white-light LED array based on a GaN nanorod structure.

Based on the experimentally demonstrated In content distribution in the InGaN/GaN quantum wells on a two-section GaN nanorod (NR) sidewall, a white-light light-emitting diode (LED) without phosphor is designed and simulated. Following the dependencies of the In diffusion length and incorporation ratio on NR geometric variables of a theoretical model, the height, radius, and tapering section geometry of the GaN NR are designed for controlling the relative intensities of a blue and a yellow emission component to mix into white light. The higher-In upper section of the NR is first excited to emit a relatively stronger yellow component when injection current is low. As the injection current increases, more current spreads into the lower-In lower section, eventually leading to a stronger blue emission component. The proposed NR LED structure provides an alternative solution for phosphor-free white-light generation.