Convergence Gas Sensors with One-Dimensional Nanotubes and Pt Nanoparticles Based on Ultraviolet Photonic Energy for Room-Temperature NO2 Gas Sensing.

Zinc oxide (ZnO) is a promising material for nitrogen dioxide (NO2) gas sensors because of its nontoxicity, low cost, and small size. We fabricated one-dimensional (1D) and zero-dimensional (0D) convergence gas sensors activated via ultraviolet (UV) photonic energy to sense NO2 gas at room temperature. One-dimensional ZnO nanorod (ZNR)-based and ZnO nanotube (ZNT)-based gas sensors were synthesized using a simple hydrothermal method. All the sensors were tested under UV irradiation (365 nm) so that they could be operated at room temperature rather than a high temperature. In addition, we decorated 0D Pt nanoparticles (NPs) on the gas sensors to further improve their sensing responsivity. The NO2-sensing response of the ZNT/Pt NP convergence gas sensor was 2.93 times higher than that of the ZNR gas sensor. We demonstrated the complex effects of UV radiation on 1D ZnO nanostructures and 0D metal nanostructures in NO2 gas sensing.

Peripheral nerve block anesthesia/analgesia for patients undergoing primary hip and knee arthroplasty: recommendations from the International Consensus on Anesthesia-Related Outcomes after Surgery (ICAROS) group based on a systematic review and meta-analysis of current literature.

BACKGROUND: Evidence-based international expert consensus regarding the impact of peripheral nerve block (PNB) use in total hip/knee arthroplasty surgery. METHODS: A systematic review and meta-analysis: randomized controlled and observational studies investigating the impact of PNB utilization on major complications, including mortality, cardiac, pulmonary, gastrointestinal, renal, thromboembolic, neurologic, infectious, and bleeding complications.Medline, PubMed, Embase, and Cochrane Library including Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, NHS Economic Evaluation Database, were queried from 1946 to August 4, 2020.The Grading of Recommendations Assessment, Development, and Evaluation approach was used to assess evidence quality and for the development of recommendations. RESULTS: Analysis of 122 studies revealed that PNB use (compared with no use) was associated with lower ORs for (OR with 95% CIs) for numerous complications (total hip and knee arthroplasties (THA/TKA), respectively): cognitive dysfunction (OR 0.30, 95% CI 0.17 to 0.53/OR 0.52, 95% CI 0.34 to 0.80), respiratory failure (OR 0.36, 95% CI 0.17 to 0.74/OR 0.37, 95% CI 0.18 to 0.75), cardiac complications (OR 0.84, 95% CI 0.76 to 0.93/OR 0.83, 95% CI 0.79 to 0.86), surgical site infections (OR 0.55 95% CI 0.47 to 0.64/OR 0.86 95% CI 0.80 to 0.91), thromboembolism (OR 0.74, 95% CI 0.58 to 0.96/OR 0.90, 95% CI 0.84 to 0.96) and blood transfusion (OR 0.84, 95% CI 0.83 to 0.86/OR 0.91, 95% CI 0.90 to 0.92). CONCLUSIONS: Based on the current body of evidence, the consensus group recommends PNB use in THA/TKA for improved outcomes. RECOMMENDATION: PNB use is recommended for patients undergoing THA and TKA except when contraindications preclude their use. Furthermore, the alignment of provider skills and practice location resources needs to be ensured. Evidence level: moderate; recommendation: strong.

Fascial plane blocks: a narrative review of the literature.

Fascial plane blocks (FPBs) are increasingly numerous and are often touted as effective solutions to many perioperative challenges facing anesthesiologists. As 'new' FPBs are being described, questions regarding their effectiveness remain unanswered as appropriate studies are lacking and publications are often limited to case discussions or technical reports. It is often unclear if newly named FPBs truly represent a novel intervention with new indications, or if these new publications describe mere ultrasound facilitated modifications of existing techniques. Here, we present broad concepts and potential mechanisms of FPB. In addition, we discuss major FPBs of (1) the extremities (2) the posterior torso and (3) the anterior torso. The characteristics, indications and a brief summary of the literature on these blocks is included. Finally, we provide an estimate of the overall level of evidence currently supporting individual approaches as FPBs continue to rapidly evolve.

Improved Performance of GaN-Based Light-Emitting Diodes Grown on Si (111) Substrates with NH3 Growth Interruption.

We demonstrate the highly efficient, GaN-based, multiple-quantum-well light-emitting diodes (LEDs) grown on Si (111) substrates embedded with the AlN buffer layer using NH3 growth interruption. Analysis of the materials by the X-ray diffraction omega scan and transmission electron microscopy revealed a remarkable improvement in the crystalline quality of the GaN layer with the AlN buffer layer using NH3 growth interruption. This improvement originated from the decreased dislocation densities and coalescence-related defects of the GaN layer that arose from the increased Al migration time. The photoluminescence peak positions and Raman spectra indicate that the internal tensile strain of the GaN layer is effectively relaxed without generating cracks. The LEDs embedded with an AlN buffer layer using NH3 growth interruption at 300 mA exhibited 40.9% higher light output power than that of the reference LED embedded with the AlN buffer layer without NH3 growth interruption. These high performances are attributed to an increased radiative recombination rate owing to the low defect density and strain relaxation in the GaN epilayer.

Intraoperative Cardiac Arrest During Adult Liver Transplantation: Incidence and Risk Factor Analysis From 7 Academic Centers in the United States.

BACKGROUND: Intraoperative cardiac arrest (ICA) has a reported frequency of 1 in 10,000 anesthetics but has a much higher estimated incidence in orthotopic liver transplantation (OLT). Single-center studies of ICA in OLT are limited by small sample size that prohibits multivariable regression analysis of risks. METHODS: Utilizing data from 7 academic medical centers, we performed a retrospective, observational study of 5296 adult liver transplant recipients (18-80 years old) between 2000 and 2017 to identify the rate of ICA, associated risk factors, and outcomes. RESULTS: ICA occurred in 196 cases (3.7% 95% confidence interval [CI], 3.2-4.2) and mortality occurred in 62 patients (1.2%). The intraoperative mortality rate was 31.6% in patients who experienced ICA. In a multivariable generalized linear mixed model, ICA was associated with body mass index (BMI) <20 (odds ratio [OR]: 2.04, 95% CI, 1.05-3.98; P = .0386), BMI ≥40 (2.16 [1.12-4.19]; P = .022), Model for End-Stage Liver Disease (MELD) score: (MELD 30-39: 1.75 [1.09-2.79], P = .02; MELD ≥40: 2.73 [1.53-4.85], P = .001), postreperfusion syndrome (PRS) (3.83 [2.75-5.34], P < .001), living donors (2.13 [1.16-3.89], P = .014), and reoperation (1.87 [1.13-3.11], P = .015). Overall 30-day and 1-year mortality were 4.18% and 11.0%, respectively. After ICA, 30-day and 1-year mortality were 43.9% and 52%, respectively, compared to 2.6% and 9.3% without ICA. CONCLUSIONS: We established a 3.7% incidence of ICA and a 1.2% incidence of intraoperative mortality in liver transplantation and confirmed previously identified risk factors for ICA including BMI, MELD score, PRS, and reoperation and identified new risk factors including living donor and length of surgery in this multicenter retrospective cohort. ICA, while rare, is associated with high intraoperative mortality, and future research must focus on therapy to reduce the incidence of ICA.

Lack of July effect in the utilization of neuraxial and peripheral nerve block in US teaching hospitals: a retrospective analysis.

BACKGROUND: Given the steep learning curve for neuraxial and peripheral nerve blocks, utilization of general anesthesia may increase as new house staff begin their residency programs. We sought to determine whether "July effect" affects the utilization of neuraxial anesthesia, peripheral nerve blocks, and opioid prescribing for lower extremity total joint arthroplasties (TJA) in July compared with June in teaching and non-teaching hospitals. METHODS: Neuraxial anesthesia, peripheral nerve block use, and opioid prescribing trends were assessed using the Premier database (2006-2016). Analyses were conducted separately for teaching and non-teaching hospitals. Differences in proportions were evaluated via χ2 test, while differences in opioid prescribing were analyzed via Wilcoxon rank-sum tests. RESULTS: A total of 1 723 256 TJA procedures were identified. The overall proportion of neuraxial anesthesia use in teaching hospitals was 14.4% in both June and July (p=0.940). No significant changes in neuraxial use were seen in non-teaching hospitals (24.5% vs 24.9%; p=0.052). Peripheral nerve block utilization rates did not differ in both teaching (15.4% vs 15.3%; p=0.714) and non-teaching hospitals (10.7% vs 10.5%; p=0.323). Overall median opioid prescribing at teaching hospitals changed modestly from 262.5 oral morphine equivalents (OME) in June to 260 in July (p=0.026) while median opioid prescribing remained at a constant value of 255 OME at non-teaching hospitals (p=0.893). CONCLUSION: Utilization of neuraxial and regional anesthesia techniques was not affected during the initial transition period of new house staff in US teaching institutions. It is feasible that enough resources are available in the system to accommodate periods of turnover and maintain levels of regional anesthetic care including additional attending anesthesiologist oversight.

Magnetically enhanced luminescence of CdSe/ZnS quantum dot light-emitting diodes using circular ferromagnetic Co/Pt multilayer disks.

We investigate the effect of a magnetic field on red, green, and blue CdSe/ZnS quantum dot light-emitting diodes (QDLEDs). Circular multilayer ferromagnetic cobalt/platinum (Co/Pt) disks are deposited on a MgF2 layer covering an Al electrode, and a perpendicular magnetic field is applied to the QDs in the active layer. Carriers injected into the active layer are then trapped and efficiently recombined inside the QDs because of strong carrier localization caused by the perpendicular magnetic field. The luminescence of the QDLEDs in the multilayer increases by 33.31% at 7.5 V, 22.34% at 7.5 V, and 16.73% at 7.0 V compared with that of QDLEDs without the multilayer. The time-resolved photoluminescence of all the QDLEDs also indicates that their increased luminescence results from improved radiative recombination through the stronger carrier localization in the QDs.

Improved efficiency of InGaN/GaN light-emitting diodes with perpendicular magnetic field gradients.

The effect of magnetic fields on the optical output power of flip-chip light-emitting diodes (LEDs) with InGaN/GaN multiple quantum wells (MQWs) was investigated. Films and circular disks comprising ferromagnetic cobalt/platinum (Co/Pt) multilayers were deposited on a p-ohmic reflector to apply magnetic fields in the direction perpendicular to the MQWs of the LEDs. At an injection current of 20 mA, the ferromagnetic Co/Pt multilayer film increased the optical output power of the LED by 20% compared to an LED without a ferromagnetic Co/Pt multilayer. Furthermore, the optical output power of the LED with circular disks was 40% higher at 20 mA than the output of the LED with a film. The increase of the optical output power of the LEDs featuring ferromagnetic Co/Pt multilayers is attributed to the magnetic field gradient in the MQWs, which increases the carrier path in the MQWs. The time-resolved photoluminescence measurement indicates that the improvement of optical output power is owing to an enhanced radiative recombination rate of the carriers in the MQWs as a result of the magnetic field gradient from the ferromagnetic Co/Pt multilayer.

Enhanced optical output in InGaN/GaN light-emitting diodes by tailored refractive index of nanoporous GaN.

The light to be trapped inside light-emitting diodes (LEDs) greatly affects the luminous efficiency and device lifetime. Abrupt difference in refractive index between the sapphire substrate and GaN-based LEDs causes light trapping by total internal reflection, however, its optical loss has been taken for granted. In this study, we demonstrate that nanoporous GaN can be used as a refractive-index-matching layer to enhance the light transmittance at the sapphire-GaN interface in InGaN/GaN flip-chip light-emitting diodes (FCLEDs). The porosity and the refractive index of the nanoporous GaN layer are controlled by electrochemical etching of n-type GaN layer. The optical output power of FCLEDs with the nanoporous GaN layer grown on flat and patterned sapphire substrates is increased by 355% and 65% at an injection current of 20 mA, respectively, compared with that of an FCLED without the nanoporous GaN layer. The remarkable enhancement of optical output is mostly attributed to the nanoporous GaN layer which drastically increases the light extraction efficiency by decreasing the reflection of light at the sapphire-GaN interface.

Enhanced performance of InGaN/GaN MQW LED with strain-relaxing Ga-doped ZnO transparent conducting layer.

We report the enhanced optical and electrical properties of InGaN/GaN multiple quantum well (MQW) light-emitting diodes (LEDs) with strain-relaxing Ga-doped ZnO transparent conducting layers (TCLs). Ga-doped ZnO was epitaxially grown on p-GaN by metal-organic chemical vapor deposition. The optical output power of a LED with a 500-nm- thick-Ga-doped ZnO TCL increased by 30.9% at 100 mA, compared with that of an LED with an indium tin oxide (ITO) TCL. Raman spectroscopy measurement and the simulation of wavefunction overlap of electron and hole in MQWs revealed that the enhanced optical output power was attributed to the increased internal quantum efficiency due to the decreased compressive strain in the active region. The increase of optical output was also attributed to the increased optical transmittance of the Ga-doped ZnO TCL owing to its higher refractive index compared to that of ITO TCL. Furthermore, the forward voltage of LED with a Ga-doped ZnO TCL was lower than that of LED with an ITO TCL because of the increased carrier concentration and mobility in the Ga-doped ZnO TCL.

Self-assembled indium tin oxide nanoball-embedded omnidirectional reflectors for high photon extraction efficiency in III-nitride ultraviolet emitters.

The control of the refractive index and electrical conductivity in the dielectric layer of omnidirectional reflectors (ODRs) is essential to improve the low efficiency of AlGaN-based UV emitters. Here, we report self-assembled indium tin oxide (ITO) nanoball-embedded omnidirectional reflectors (NODRs) for use in high-efficiency AlGaN-based UV emitters at 365 nm. These NODRs consisted of a reflective Al layer, a self-assembled conducting ITO nanoball layer for current injection and spreading, and nanovoids that provided a low refractive index to achieve highly efficient UV emitters. The NODR was able to realize both high electrical conductivity and reflectivity by decreasing the average refractive index of the ITO nanoball layers. We observed diffuse reflection as well as omnidirectional reflection from the NODR UV emitters because of the corrugated interfaces of the nanovoids, ITO nanoball layer, and Al layer. These structural and optical properties of the NODRs remarkably increased the output power of a UV emitter by a Lambertian enhancement factor of 57% at an injection current of 50 mA at all emission angles compared with that of an ITO film/Al UV emitter.

Accumulation and temporal changes of PCDD/Fs and dioxin-like PCBs in finless porpoises (Neophocaena asiaeorientalis) from Korean coastal waters: Tracking the effectiveness of regulation.

Temporal trend studies are useful to evaluate the effectiveness of regulations on local pollutants. The emission of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) has been regulated by the Korean government in accordance with the Stockholm Convention. The accumulation and temporal trends of PCDD/Fs and dioxin-like PCBs were investigated in finless porpoises (Neophocaena asiaeorientalis) collected in Korean waters. Median concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs were 1.0, 1.1, 0.1, and 1.8pgTEQ/g lipid weight, respectively, which were lower than threshold values for marine mammals. Age- and sex-dependent accumulation patterns were found for PCDFs and DL-PCBs. Temporal trends in finless porpoises collected between 2003 and 2010 showed significant reduction rates of 57%, 54%, 69%, and 60% for PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs, respectively. Our results suggest that the regulations on dioxin-like contaminants have been effective for marine mammals in Korea.

Species-specific accumulation of methyl and total mercury in sharks from offshore and coastal waters of Korea.

Limited information is available on mercury (Hg) levels in various shark species consumed in Korea. The methyl-Hg (Me-Hg) and total Hg concentrations in all shark species ranged from 0.08 to 4.5 (mean: 1.2) mg/kg wet weight and from 0.1 to 7.0 (mean: 1.4) mg/kg wet weight, respectively. Inter-species differences in Hg accumulation were found among the species; however, Hg accumulation was homogenous between dorsal and pectoral fins within species. The highest Hg levels were found in aggressive carnivore shark species. Trophic position was important in determining Hg accumulation for aggressive carnivore sharks. Approximately 80% of shark species exceeded the safety limits for Me-Hg established by domestic and international authorities. The mean estimated daily intake of Me-Hg (1.3 µg/kg body weight/day) for Korean populations consuming various sharks was higher than the guidelines proposed by international regulatory authorities, suggesting that excessive shark fin consumption may pose potential health risks for Koreans.

Enhanced optical output power of InGaN/GaN light-emitting diodes grown on a silicon (111) substrate with a nanoporous GaN layer.

We report the growth of InGaN/GaN multiple quantum wells blue light-emitting diodes (LEDs) on a silicon (111) substrate with an embedded nanoporous (NP) GaN layer. The NP GaN layer is fabricated by electrochemical etching of n-type GaN on the silicon substrate. The crystalline quality of crack-free GaN grown on the NP GaN layer is remarkably improved and the residual tensile stress is also decreased. The optical output power is increased by 120% at an injection current of 20 mA compared with that of conventional LEDs without a NP GaN layer. The large enhancement of optical output power is attributed to the reduction of threading dislocation, effective scattering of light in the LED, and the suppression of light propagation into the silicon substrate by the NP GaN layer.

Polybrominated diphenyl ethers in thirteen shark species from offshore and coastal waters of Korea.

Limited reports are available on polybrominated diphenyl ethers (PBDEs) in sharks. In this study, PBDEs were measured in dorsal muscles (n=105) from 13 shark species collected from offshore and coastal waters of Korea. The PBDE concentrations varied greatly not only among species but also within species of sharks. The major PBDE congeners detected in our samples were BDEs 47, 28, 99, 153, 100, and 154. Concentrations of PBDEs in sharks in this study were lower than those reported for previous studies. The high PBDE concentrations were found for aggressive shark species. Inter-species differences in the concentrations and accumulation profiles of PBDEs are explained by differences in feeding habits and sampling locations. Several contributing factors such as growth velocity, trophic level, and local contamination may affect the bioaccumulation of PBDEs in sharks. The present study provides baselines for the occurrence and accumulation status of PBDEs in various shark species.

Persistent organochlorines in 13 shark species from offshore and coastal waters of Korea: Species-specific accumulation and contributing factors.

Data on persistent organochlorines (OCs) in sharks are scarce. Concentrations of OCs such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were determined in the muscle tissue of 13 shark species (n=105) collected from offshore (Indian and Pacific Oceans) and coastal waters of Korea, to investigate species-specific accumulation of OCs and to assess the potential health risks associated with consumption of shark meat. Overall OC concentrations were highly variable not only among species but also within the same species of shark. The concentrations of PCBs, DDTs, chlordanes, hexachlorobenzene, and heptachlor in all shark species ranged from

Improvement in the Electrical Performance of Ge-Doped InZnO Thin-Film Transistor.

We fabricated amorphous oxide semiconductor thin-film transistors (TFTs) using Ge-doped InZnO (Ge-IZO) thin films as active-channel layers. The Ge-IZO thin films were deposited at room temperature by radio-frequency (RF) magnetron co-sputtering system, and then annealed in air for 1 h at 300 °C. Some processing parameters such as sputtering oxygen partial pressure [O2/(Ar + O2)] and sputtering power for GeO2 target were changed to investigate what was the optimal amount of Ge in the Ge-IZO active layer. A small concentration of Ge added to IZO by co-sputtering enhanced the carrier concentration, mobility, and conductivity; but further increase in Ge concentration degraded the device performance. In order to optimize the electrical properties of Ge-IZO TFTs, we tried to adjust the processing parameters and the best Ge-IZO TFT was obtained at a co-sputtering oxygen partial pressure of 2% and GeO2 target power of 10 W. The fabricated Ge-IZO TFT exhibited an on/off ratio of 3.0 x 10(7), a saturation mobility of 13.05 cm2/V·s, a subthreshold swing of 0.95 V/dec, and a threshold voltage of 0 V. XPS and XRD analyses of Ge-IZO films were performed to investigate the binding energies of atoms in Ge-IZO films and the crystallinity of the films. 90% transmittance of visible light was achieved, which makes the technology useful for transparent devices.

Effects of Double Active Layer and Acetic Acid Stabilizer on the Electrical Properties of a Solution-Processed Zinc Tin Oxide Thin-Film Transistor.

We investigated the effects of a double active layer (DAL) and acetic acid stabilizer on zinc tin oxide (ZTO) thin-film transistors (TFTs) fabricated using a solution process. The DAL was composed of two layers created by a ZTO solution doped with the same or different percentiles of an atomic Sn concentration (30 at.%, 60 at.%). The electrical performance of the ZTO TFTs significantly was improved after we added acetic acid (AA) instead of monoethanolamine (MEA). This was accomplished by applying a type 2 DAL (bottom layer: Sn 60 at.%, top layer: Sn 30 at.%, 60/30) instead of other types (30/30 or 60/60). It was demonstrated that AA plays a role in lowering the decomposition temperature, enhancing the metal-oxygen bridge, and decreasing hydroxyl groups in the film. In addition, the type 2 DAL structure (60/30) lowered the Ioff of the ZTO TFT and controlled the carrier concentration in the channel. The best performances were obtained at a Sn concentration of 60 at.% in the bottom ZTO layer and 30 at.% in the top ZTO layer, with AA added as a stabilizer. The ZTO TFT exhibited an on/off ratio of 1.1 x 10(9), a saturation mobility of 5.04 cm2/V·s, a subthreshold slope of 0.11 V/decade, and a threshold voltage of 1.6 V.

Enhanced performance of InGaN/GaN multiple-quantum-well light-emitting diodes grown on nanoporous GaN layers.

We demonstrate the high efficiency of InGaN/GaN multiple quantum wells (MQWs) light-emitting diode (LED) grown on the electrochemically etched nanoporous (NP) GaN. The photoluminescence (PL) and Raman spectra show that the LEDs with NP GaN have a strong carrier localization effect resulting from the relaxed strain and reduced defect density in MQWs. Also, the finite-difference time-domain (FDTD) simulation shows that the light extraction efficiency (LEE) is increased by light scattering effect by nanopores. The output power of LED with NP GaN is increased up to 123.1% at 20 mA, compared to that of LED without NP GaN. The outstanding performance of LEDs with NP GaN is attributed to the increased internal quantum efficiency (IQE) by the carrier localization in the indium-rich clusters, low defect density in MQWs, and increased LEE owing to the light scattering in NP GaN.