Chemically-defined and scalable culture system for intestinal stem cells derived from human intestinal organoids.

Three-dimensional human intestinal organoids (hIO) are widely used as a platform for biological and biomedical research. However, reproducibility and challenges for large-scale expansion limit their applicability. Here, we establish a human intestinal stem cell (ISC) culture method expanded under feeder-free and fully defined conditions through selective enrichment of ISC populations (ISC3D-hIO) within hIO derived from human pluripotent stem cells. The intrinsic self-organisation property of ISC3D-hIO, combined with air-liquid interface culture in a minimally defined medium, forces ISC3D-hIO to differentiate into the intestinal epithelium with cellular diversity, villus-like structure, and barrier integrity. Notably, ISC3D-hIO is an ideal cell source for gene editing to study ISC biology and transplantation for intestinal diseases. We demonstrate the intestinal epithelium differentiated from ISC3D-hIO as a model system to study severe acute respiratory syndrome coronavirus 2 viral infection. ISC3D-hIO culture technology provides a biological tool for use in regenerative medicine and disease modelling.

Insight into Defect Engineering of Atomically Dispersed Iron Electrocatalysts for High-Performance Proton Exchange Membrane Fuel Cell.

Atomically dispersed and nitrogen coordinated iron catalysts (Fe-NCs) demonstrate potential as alternatives to platinum-group metal (PGM) catalysts in oxygen reduction reaction (ORR). However, in the context of practical proton exchange membrane fuel cell (PEMFC) applications, the membrane electrode assembly (MEA) performances of Fe-NCs remain unsatisfactory. Herein, improved MEA performance is achieved by tuning the local environment of the Fe-NC catalysts through defect engineering. Zeolitic imidazolate framework (ZIF)-derived nitrogen-doped carbon with additional CO2 activation is employed to construct atomically dispersed iron sites with a controlled defect number. The Fe-NC species with the optimal number of defect sites exhibit excellent ORR performance with a high half-wave potential of 0.83 V in 0.5 M H2 SO4 . Variation in the number of defects allows for fine-tuning of the reaction intermediate binding energies by changing the contribution of the Fe d-orbitals, thereby optimizing the ORR activity. The MEA based on a defect-engineered Fe-NC catalyst is found to exhibit a remarkable peak power density of 1.1 W cm-2 in an H2 /O2 fuel cell, and 0.67 W cm-2  in an H2 /air fuel cell, rendering it one of the most active atomically dispersed catalyst materials at the MEA level.

An On-/Off-Time Sensing-Based Load-Adaptive Mode Control of Triple Mode Buck Converter for Implantable Medical Devices.

Wireless power transfer (WPT) technology applied to implantable medical devices (IMDs) significantly reduces the need for battery replacement surgery health conditions. This paper presents an on-/off-time sensing-based load-adaptive mode control of triple mode buck converter for implantable medical devices; the converter can adjust the control mode for low power consumption and achieve high power conversion efficiency (PCE) under a small active area. The three modes in the proposed system are the pulse width modulation (PWM), pulse frequency modulation (PFM), and ultra-low power (ULP) modes. The on-time sensor can be used to adjust the system from PWM to PFM modes, and the off-time sensor can be used to adjust the system from PFM to ULP modes. It is fabricated using TSMC 0.18 µm CMOS technology. The input voltage lies in the range 2.2-5.0 V, the output voltage is 1.8 V, and the load current lies in the range 0.05-200 mA (x4000). The experimental results demonstrate the seamless mode transition under the step up/down load transient response. The peak PCE is approximately 94.3% at the 80 mA and the minimum PCE is approximately 65.4% within the load current range.

Reinforced Nafion Membrane with Ultrathin MWCNTs/Ceria Layers for Durable Proton-Exchange Membrane Fuel Cells.

For further commercializing proton-exchange membrane fuel cells, it is crucial to attain long-term durability while achieving high performance. In this study, a strategy for modifying commercial Nafion membranes by introducing ultrathin multiwalled carbon nanotubes (MWCNTs)/CeO2 layers on both sides of the membrane was developed to construct a mechanically and chemically reinforced membrane electrode assembly. The dispersion properties of the MWCNTs were greatly improved through chemical modification with acid treatment, and the mixed solution of MWCNTs/CeO2 was uniformly prepared through a high-energy ball-milling process. By employing a spray-coating technique, the ultrathin MWCNTs/CeO2 layers were introduced onto the membrane surfaces without any agglomeration problem because the solvent rapidly evaporated during the layer-by-layer stacking process. These ultrathin and highly dispersed MWCNTs/CeO2 layers effectively reinforced the mechanical properties and chemical durability of the membrane while minimizing the performance drop despite their non-ion-conducting properties. The characteristics of the MWCNTs/CeO2 layers and the reinforced Nafion membrane were investigated using various in situ and ex situ measurement techniques; in addition, electrochemical measurements for fuel cells were conducted.

Limosilactobacillus reuteri DS0384 promotes intestinal epithelial maturation via the postbiotic effect in human intestinal organoids and infant mice.

Little is known about the modulatory capacity of the microbiota in early intestinal development. We examined various intestinal models that respond to gut microbial metabolites based on human pluripotent stem cell-derived human intestinal organoids (hIOs): physiologically relevant in vitro fetal-like intestine, intestinal stem cell, and intestinal disease models. We found that a newly isolated Limosilactobacillus reuteri strain DS0384 accelerated maturation of the fetal intestine using 3D hIO with immature fetal characteristics. Comparative metabolomic profiling analysis revealed that the secreted metabolite N-carbamyl glutamic acid (NCG) is involved in the beneficial effect of DS0384 cell-free supernatants on the intestinal maturation of hIOs. Experiments in an intestinal stem cell spheroid model and hIO-based intestinal inflamed model revealed that the cell-free supernatant from DS0384 comprising NCG promoted intestinal stem cell proliferation and was important for intestinal protection against cytokine-induced intestinal epithelial injury. The probiotic properties of DS0384 were also evaluated, including acid and bile tolerance and ability to adhere to human intestinal cells. Seven-day oral administration of DS0384 and cell-free supernatant promoted the intestinal development of newborn mice. Moreover, NCG exerted a protective effect on experimental colitis in mice. These results suggest that DS0384 is a useful agent for probiotic applications and therapeutic treatment for disorders of early gut development and for preventing intestinal barrier dysfunction.

The effect of probiotic supplementation on systemic inflammation in dialysis patients.

BACKGROUND: Emerging evidence suggests that intestinal dysbiosis contributes to systemic inflammation and cardiovascular diseases in dialysis patients. The purpose of this study was to evaluate the effects of probiotic supplementation on various inflammatory parameters in hemodialysis (HD) patients. METHODS: Twenty-two patients with maintenance HD were enrolled. These patients were treated twice a day with 2.0 ×1010 colony forming units of a combination of Bifidobacterium bifidum BGN4 and Bifidobacterium longum BORI for 3 months. The microbiome and fecal short-chain fatty acids (SCFAs) were analyzed. The percentages of CD14+ CD16+ proinflammatory monocytes and CD4+ CD25+ regulatory T-cells (Tregs) before and after probiotic supplementation were determined by flow cytometry. Serum levels of calprotectin and cytokine responses upon lipopolysaccharide (LPS) challenge were compared before and after probiotic supplementation. RESULTS: Fecal SCFAs increased significantly after probiotic supplementation. Serum levels of calprotectin and interleukin 6 upon LPS stimulation significantly decreased. The anti-inflammatory effects of probiotics were associated with a significant increase in the percentage of CD4+ CD25+ Tregs (3.5% vs. 8.6%, p < 0.05) and also with a decrease of CD14+ CD16+ proinflammatory monocytes (310/ mm2 vs. 194/mm2 , p < 0.05). CONCLUSION: Probiotic supplementation reduced systemic inflammatory responses in HD patients and this effect was associated with an increase in Tregs and a decrease in proinflammatory monocytes. Hence, targeting intestinal dysbiosis might be a novel strategy for decreasing inflammation and cardiovascular risks in HD patients.

Modified Frailty Index (mFI) predicts 30-day complications after microsurgical breast reconstruction.

Frailty lacks a universal definition. The modified Frailty Index (mFI) using patient comorbidities can be used to measure frailty. We hypothesized that mFI predicts 30-day complications after microsurgical breast reconstruction. American College of Surgeons' (ACS) National Surgical Quality Improvement Project (NSQIP) was investigated to identify patients undergoing microsurgical breast reconstruction between 2005-2014 using Current Procedure Terminology (CPT) code, 19364. We used mFI as a measure of frailty. The patients were assigned a frailty score based on the number of preoperative comorbid conditions as defined by the mFI. Other risk indices used include age, BMI, wound class, ASA class. Stratification was performed in ascending order for each. The outcome measure was aggregate 30-day complications. Regression analysis was performed followed by Receptor Operating Characteristic (ROC) curve to determine the accuracy of each risk index in predicting 30-day complications. Of the 3237 patients 24% experienced complications. Univariate logistic regression analysis found odds ratio of complications for frailty score 1 = 22.1 (CI = 17.9-27.3, p < 0.01), and 2 = 28 (CI = 18.3-43, p < 0.01) compared to frailty score = 0. ROC curve demonstrated mFI with the highest concordance score (c-score = 0.816). Multivariable logistic regression found frailty as the strongest independent predictor of 30-day aggregate complications adjusted OR = 22.24, CI = 17.77-27.82, p < 0.01 when compared to other risk indices. The modified Frailty Index is a simple, reliable, and objective tool that can be used to predict postoperative complications after microsurgical breast reconstruction. The application of this tool can help microsurgeons preoperatively identify patients who are at high risk.Abbreviations: ACS: American College of Surgeons; ASA: American Society of Anesthesiologists; BMI: body mass index; CHF: congestive heart failure; CPT: current procedural terminology; COPD: chronic obstructive pulmonary disease; CVA: cerebrovascular accident; DM: diabetes mellitus; IRB: institutional review board; mfi: modified frailty index; MI: myocardial infarction; NSQIP: national surgical quality improvement program; PVD: peripheral vascular disease; ROC: receptor operating characteristic; TIA: transient ischemic attach.

Risk Factors for 30-Day Mortality After Head and Neck Microsurgical Reconstruction for Cancer: NSQIP Analysis.

OBJECTIVE: To identify the incidence and risk factors for 30-day postoperative mortality after microsurgical head and neck reconstruction following oncological resection. STUDY DESIGN: Retrospective case-control study. SETTING: American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. METHODS: Microsurgical head and neck reconstructive cases were identified from 2005 to 2018 using Current Procedural Terminology codes and oncologic procedures using the International Classification of Disease 9 and 10 codes. The outcome of interest was 30-day mortality. RESULTS: The 30-day postoperative mortality rate was 1.2%. Univariate logistic regression analysis identified the following associations: age >80 years, hypertension, poor functional status, preoperative wound infection, renal insufficiency, malnutrition, anemia, and prolonged operating time. Multivariable logistic regression models were used to stratify further by the degree of malnutrition and anemia. Hematocrit <30% was found to be an independent risk factor for 30-day postoperative mortality (odds ratio [OR] = 9.59, confidence interval [CI] 2.32-39.65, P < .1) with albumin <3.5 g/dL. This association was even stronger with albumin <2.5 g/dL (OR = 11.64, CI 3.06-44.25, P < .01). One-third of patients (36.6%) had preoperative anemia, of which less than 1% required preoperative transfusion, although one-quarter (24.6%) required intraoperative or 72 hours postoperative transfusion. CONCLUSIONS: Preoperative anemia is a risk factor for 30-day postoperative mortality. This association seems to get stronger with worsening anemia. Identification and optimization of such patients preoperatively may mitigate the incidence of 30-day postoperative mortality.

Uncovering the encapsulation effect of reduced graphene oxide sheets on the hydrogen storage properties of palladium nanocubes.

Decades of research on solute-induced phase transformation of metal hydride systems have shown the possibility to enhance hydrogen storage properties through novel material design such as nanoconfinement engineering. Nevertheless, the fundamentals of mechanical stress effect on confined Pd nanoparticles remain yet to be elucidated due to the difficulty in linking with hydrogen sorption thermodynamics. Here, a thermodynamic tuning of Pd nanocubes associated with hydrogen sorption as a result of encapsulation by reduced graphene oxide (rGO) layers is demonstrated. Pd nanocubes are constrained by rGO to such a degree that the chemical potential and the pressure hysteresis of the system during hydrogen sorption drastically change while showing a size dependence. A thorough thermodynamic analysis elucidates the role of constraints on hydrogen uptake and release; despite the nanoscale regime, the thermodynamic parameters (enthalpy and entropy) during phase transition considerably increase, a phenomenon not seen before in unconstrained Pd nanoparticle systems.

Perioperative Safety of Combined Augmentation-Mastopexy: An Evaluation of National Database.

INTRODUCTION: The safety of combined augmentation-mastopexy is controversial. This study evaluates a national database to analyze the perioperative safety of combined augmentation-mastopexy to either augmentation or mastopexy alone. METHODS: The American College of Surgeons National Surgical Quality Improvement Program database was queried to identify patients undergoing augmentation mammaplasty and mastopexy from 2005 to 2018. The patients were divided into the following groups: group I, augmentation; group II, mastopexy; group III, combined augmentation-mastopexy. Baseline characteristics and outcomes were compared. Outcomes were 30-day complications, reoperation, and readmission. RESULTS: We found 5868 (74.2%) augmentation only, 1508 (19.1%) mastopexy only and 534 (6.6%) combined augmentation-mastopexy cases. Mean operative time was highest among the combined group at 129 minutes compared with 127 minutes for mastopexy alone and 66 minutes for augmentation alone (P < 0.01). Rates of any complications and readmission were different among groups (0.8% vs 2.5% vs 1.5% respectively, P < 0.01 and 0.7% vs 1.5% vs 1.5% respectively, P = 0.049), whereas reoperation was not statistically different (1.2% vs 1.4% vs 1.5%, P = 0.75). The incidence of dehiscence (0.6%; P < 0.01) was highest in the combined group. Multivariable logistic regression analysis did not reveal an increased odds of complications, reoperation, or readmission with combined augmentation-mastopexy. CONCLUSIONS: An evaluation of the nationwide cohort suggests that combined augmentation-mastopexy is a safe procedure in the perioperative period.

A 6.78 MHz, 95.0% Peak Efficiency Monolithic Two-Dimensional Calibrated Active Rectifier for Wirelessly Powered Implantable Biomedical Devices.

In this paper, a fully integrated active rectifier with triple feedback loops is proposed to enhance power conversion efficiency (PCE) over a wide loading range by calibrating both the gate transition timing and power switch size. The on- and off-transitions of the power switches are calibrated using a hybrid delay-based gate control circuit (HDGCC) with hybrid feedback loops. Conventional active rectifiers that only focused on calibrating the gate transition timing of a NMOS power switch with a fixed power switch size exhibit a low PCE when the loading condition deviates from the predetermined range. Thus, an automatic size selector based on a third feedback loop is proposed, which changes the power switch size based on the loading condition and ensures a stable operation of the hybrid loops by maintaining the voltage drop across the NMOS switches. An active rectifier was fabricated using the standard 0.18 µm CMOS process. The effectiveness and robustness of the two-dimensional calibration were verified through measurements under an AC input voltage ranging from 2.5 to 5.0 V and an output power ranging from 1.25 to 125 mW. The peak voltage conversion ratio and peak PCE were 97.6% and 95.0%, respectively, at RL = 500 Ω.

Surface Area Graphic Evaluation (SAGE) Diagram Documentation in Burn Patients: Room for Quality Improvement.

Background The first step in the management of burn patients is an accurate estimation of the total body surface area (TBSA) involvement. Depending on which, burns are categorized as major (>20%) and minor (<20%). This then dictates fluid resuscitation and level of care. At the University of New Mexico Burn Center, we use Surface Area Graphic Evaluation (SAGE) diagramming to objectively estimate the body surface area involvement. We hypothesized patients undergoing SAGE documentation will have better outcomes.  Methods This is a retrospective study of 320 consecutive patients from 2014-2018 at the University of New Mexico Burn Center. Only patients treated surgically were included. We recorded patient demographics, comorbidities, and burn details. The primary measure of interest was SAGE documentation and the secondary measure of interest was outcomes associated with it. Results We found that a SAGE diagram was only documented for a minority of patients (40%). After comparing patients in the SAGE group vs. No SAGE group, we found that the patients were the same in both groups with regards to demographics, comorbidities, and burn characteristics. The use of a SAGE diagram did not appear to be a significant predictor of complications, including surgical site infections, graft loss, donor site complications, postoperative pneumonia, urinary tract infections, deep vein thrombosis, or myocardial infarction (p=0.254). Conclusion Only a minority of patients get a SAGE diagram documented. However, our study did not find any improved outcomes with the use of a SAGE diagram. There is a need for prospective studies to validate the utility of SAGE diagramming in predicting adverse outcomes in major burns.

Inpatient Versus Outpatient Operative Management of Isolated Facial Fractures.

BACKGROUND: Patients with isolated facial fractures requiring operative fixation can be managed on an inpatient or outpatient basis. The goal of this study was to compare the safety of each approach using a large multi-institutional database. METHODS: The American College of Surgeons' National Surgical Quality Improvement Project was reviewed for facial fractures between 2005 and 2018. Groups were identified using inpatient and outpatient status as designated in the database. Patients who required additional procedures, concurrent procedures, or other emergency procedures were excluded. Descriptive statistics were used for group comparisons and logistic regression models were used to identify risk factors for complications. RESULTS: We identified 4240 patients who underwent operative fixation of isolated facial fractures. The majority of these cases (67.9%) were done on an outpatient basis. Compared to those in the outpatient group, patients in the inpatient group were older, had more medical comorbidities, had higher wound class, and had higher American Society of Anesthesiologists class. Complication (5.9% versus 2.3%), reoperation (4.3% versus 1.7%), and readmission (5.7% versus 2.5%) rates were all higher in the inpatient group (P < 0.01). By logistic regression analysis, the odds ratios for complications, reoperation, and readmission were higher in the inpatient group. After adjusting for imbalanced preoperative patient characteristics, the increased risk of complications [odds ratio (OR) = 1.728, confidence interval (CI) 1.146-2.606, P = 0.01] and the increased risk of reoperation (OR = 2.302, CI 1.435-3.692, P = 0.01) in the inpatient group persisted, while the risk of readmission (OR = 1.684, CI 0.981-2.891, P = 0.06) no longer showed statistical significance between the inpatient and outpatient groups. CONCLUSIONS: Inpatient operative management of isolated facial fractures is associated with an increased risk of complications and a 2-fold increased risk of reoperation, though no increased risk of readmission.

Development of Magnesium-Based Material with Hydrogen-Storage Capacity of 7 wt.

TiCl3 was chosen as an additive to increase hydriding and dehydriding rates of Mg. In our previous works, we found that the optimum percentage of additives that improved the hydriding and dehydriding features of Mg was approximately ten. Specimens consisting of 90 wt% Mg and 10 wt% TiCl3 (named Mg-10TiCl3) were prepared by high-energy ball milling in hydrogen. The specimens' hydriding and dehydriding properties were then studied. Mg-10TiCl3 had an effective hydrogenstorage capacity (the quantity of hydrogen absorbed in 60 min) of approximately 7.2 wt% at 593 K under 12 bar H2 at the second cycle. After high-energy ball milling in hydrogen, Mg-10TiCl3 contained Mg, ß-MgH2, and small amounts of γ-MgH2 and TiH1.924. TiH1.924 remained undercomposed even after dehydriding at 623 K in a vacuum for 2 h. The hydriding and dehydriding properties of Mg-10TiCl3 were compared with those of other specimens such as Mg-10Fe2O3, Mg-10NbF5, and Mg-5Fe2O3-5Ni, for which the hydrogen-storage properties were previously reported.

Lung aspergilloma with pituitary invasive aspergillosis presenting as headache and hyponatraemia.

Fungal infections involving the pituitary gland are rare and can be life threatening. A 75-year-old man with hypertension and diabetes mellitus presented with headache and hyponatraemia. Imaging study showed right upper lung mass, and mass resection showed aspergilloma without tissue invasion on histology. The patient developed visual impairment a few weeks later, and MRI of the brain revealed bilateral sphenoid sinusitis and pituitary invasion. The trans-sphenoidal biopsy confirmed invasive Aspergillus infection. His sphenoidal sinuses were endoscopically debrided, and he was treated with oral voriconazole. Pituitary aspergillosis should be considered in the differential diagnosis in patients with lung aspergilloma with headache and sinusitis. Prompt biopsy and antifungal treatment are important due to the high mortality rate of the infection.

Morbidity Associated With Structural Graft Use in Paramedian Forehead Flap.

INTRODUCTION: Paramedian forehead flap for nasal reconstruction may involve the use of a structural graft. The authors hypothesized that the use of structural grafts with paramedian forehead flap is associated with an increased risk of 30-day complications. METHODS: This is a retrospective study of the American College of Surgeon (ACS) National Surgical Quality Improvement Program (NSQIP). We identified all patients undergoing paramedian forehead flap reconstruction from 2007 through 2018 using Current Procedural Terminology code 15731. Patients who had structural graft harvested at the time of paramedian forehead flap were identified using Current Procedural Terminology codes. Groups were defined based on the use of structural grafts. Propensity score matching was performed using preoperative and intraoperative characteristics to produce matched cohorts. The authors further stratified individual graft types to identify differential risks associated with each. Logistic regression was then used to determine whether the use of structural grafts was associated with increased risk for 30-day complications. RESULTS: The authors identified 1198 patients with paramedian forehead flap reconstruction, of whom 325 (27.1%) required structural grafts. Propensity score matching 1:1 yielded 247 patients in each of the matched cohorts. Overall 30-day complications (4.5% versus 5.3%), wound related complications (3.2% versus 4.1%), systemic complications (1.2% versus 2%), unplanned reoperation (6.5% versus 3.2%), and unplanned readmission (6.6% versus 10.2%) were similar between the 2 groups (P > 0.05). Subgroup analysis of different graft types showed that costochondral graft was associated with increased wound related complications (0.9% versus 8.3%, P = 0.03). The odds of having wound related complications with the use of costochondral graft was OR = 5.3, CI = 1.5-18.8, P = 0.02. CONCLUSIONS: Although the use of structural grafts does not increase risk of overall 30-day complications, there is an increased risk of wound related complications associated with the use of costochondral and rib grafts.

Rate-Controlling Steps for the Hydriding Reaction of the Intermetallic Compound Mg2Ni.

Mg2Ni samples were prepared by sintering a pelletized mixture under an argon atmosphere in a stainless steel crucible at 823 K. The XRD pattern of the prepared Mg2Ni sample showed a well crystallized Mg2Ni phase. The hydriding and dehydriding properties of the prepared samples were examined at 518-593 K under relatively low hydrogen pressures of 3-7 bar H2. At 573 K under 7 bar H2, the activation of the Mg2Ni sample was completed at the number of cycles of six (n = 6). At n = 7, the hydrided fractions of the sample were 0.53 (1.99 wt% H) at 4.97 min, 0.72 (2.71 wt% H) at 9.52 min, 0.81 (3.05 wt% H) at 31.15 min, and 0.81 (3.05 wt% H) at 60.07 min. The particle sizes of the prepared Mg2Ni were not homogeneous and the particles had irregular shapes. We analyzed the rate-controlling steps for the hydriding reaction of the intermetallic compound Mg2Ni by examining the dependences of hydriding rates on hydrogen pressure and temperature in the same reacted fraction ranges. The analyses in the same reacted fraction ranges were done in order to eliminate the influence of the interfacial area on the hydriding rate. When the driving force, which is the difference between the applied hydrogen pressure Po and equilibrium plateau pressure Peq at a given temperature, was low, the nucleation of Mg2Ni hydride controlled the hydriding rate of Mg2Ni. After the nucleation of the Mg2Ni hydride, the rate-controlling step of the hydriding reaction of Mg2Ni was analyzed to be the forced flow of hydrogen molecules through pores, inter-particle channels, or cracks.

Increasing the Hydrogenation and Dehydrogenation Rates of Magnesium by Incorporating CMC(Na) (Carboxymethylcellulose-Sodium Salt) and Nickel.

Samples with compositions of 95 wt% Mg + 5 wt% CMC(Na) [carboxymethylcellulose, sodium salt, {C6H7O2(OH)x(C2H2O3Na)y}n] [named Mg-5CMC(Na)] and 90 wt% Mg + 10 wt% CMC(Na) [named Mg-10CMC(Na)] were prepared via milling in hydrogen (hydride-forming milling). Mg-5CMC(Na) and Mg-10CMC(Na) had very high hydrogenation rates but low dehydrogenation rates. Adding Ni to Mg is known to increase the hydrogenation and dehydrogenation rates of Mg. We chose Ni as an additive to increase dehydrogenation rates of Mg-5CMC(Na) and Mg-10CMC(Na). A sample with a composition of 90 wt% Mg + 5 wt% CMC + 5 wt% Ni [named Mg-5Ni-5CMC(Na)] was prepared via hydride-forming milling. The activation of Mg-5Ni-5CMC(Na) was completed at the third hydrogenation-dehydrogenation cycle (N ═ 3). Mg-5Ni-5CMC(Na) had an effective hydrogen-storage capacity (the quantity of hydrogen absorbed for 60 min) of 5.83 wt% at 593 K in 12 bar hydrogen at N ═ 3. Mg-5Ni-5CMC(Na) released 2.73 wt% H for 10 min and 4.61 wt% H for 60 min at 593 K in 1.0 bar hydrogen at N ═ 3. Mg-5Ni-5CMC(Na) dehydrogenated at N ═ 4 contained Mg and small amounts of MgO, ß-MgH2, Mg2Ni, and Ni. Hydride-forming milling of Mg with CMC and Ni and Mg2Ni formed during hydrogenation-dehydrogenation cycling are believed to have increased the dehydrogenation rates of Mg-5CMC(Na) and Mg-10CMC(Na). As far as we know, this study is the first in which a polymer CMC(Na) and Ni were added to Mg via hydride-forming milling to improve the hydrogenation and dehydrogenation rates of Mg.

Enhancement of light-extraction efficiency of organic light-emitting diodes using silica nanoparticles embedded in TiO2 matrices.

We investigate two types of internal light-extraction layer structures for organic light-emitting diodes (OLEDs) that consist of silica nanoparticles (NPs) embedded in high-refractive-index TiO2 matrices. The composite of silica NPs and TiO2 matrices was coated on the glass substrate and fabricated with and without a SiO2 planarization layer. An increase in the optical out-coupling efficiency by a factor of 2.0 was obtained at a high luminance of 3,000 cd/m² from OLEDs containing the silica NPs embedded in TiO2 matrices between glass substrates and Zn-doped In2O3 (IZO) electrodes after additional planarization processes. This is consistent with the analytical result using the finite-difference time-domain (FDTD) method. Randomly distributed silica NPs acting as scattering centers could reduce the optical loss when extracting light. By using additional planarization processes with a PECVD-derived SiO2 layer, one can assure that smoother surfaces provide higher out-coupling efficiency, which attain 100% and 97% enhancements in power (lm/W) and current (cd/A) efficiencies, respectively.