Effectiveness of regdanvimab treatment for SARS-CoV-2 delta variant, which exhibited decreased in vitro activity: a nationwide real-world multicenter cohort study.

Background: Immune-evading severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants are emerging continuously. The clinical effectiveness of monoclonal antibody agents that exhibit decreased in vitro activity against SARS-CoV-2 variants needs to be elucidated. Methods: A nationwide, multicenter, retrospective cohort study was designed to evaluate the effectiveness of regdanvimab, an anti-SARS-CoV-2 monoclonal antibody agent. Regdanvimab was prescribed in South Korea before and after the emergence of the delta variant, against which the in vitro activity of regdanvimab was decreased but present. Mild to moderate coronavirus 2019 (COVID-19) patients with risk factors for disease progression who were admitted within seven days of symptom onset were screened in four designated hospitals between December 2020 and September 2021. The primary outcomes, O2 requirements and progression to severe disease within 21 days of admission, were compared between the regdanvimab and supportive care groups, with a subgroup analysis of delta variant-confirmed patients. Results: A total of 2,214 mild to moderate COVID-19 patients were included, of whom 1,095 (49.5%) received regdanvimab treatment. In the analysis of the total cohort, significantly fewer patients in the regdanvimab group than the supportive care group required O2 support (18.4% vs. 27.1%, P < 0.001) and progressed to severe disease (4.0% vs. 8.0%, P < 0.001). In the multivariable analysis, regdanvimab was significantly associated with a decreased risk for O2 support (HR 0.677, 95% CI 0.561-0.816) and progression to severe disease (HR 0.489, 95% CI 0.337-0.709). Among the 939 delta-confirmed patients, O2 support (21.5% vs. 23.5%, P = 0.526) and progression to severe disease (4.2% vs. 7.3%, P = 0.055) did not differ significantly between the regdanvimab and supportive care groups. In the multivariable analyses, regdanvimab treatment was not significantly associated with a decreased risk for O2 support (HR 0.963, 95% CI 0.697-1.329) or progression to severe disease (HR 0.665, 95% CI 0.349-1.268) in delta-confirmed group. Conclusions: Regdanvimab treatment effectively reduced progression to severe disease in the overall study population, but did not show significant effectiveness in the delta-confirmed patients. The effectiveness of dose increment of monoclonal antibody agents should be evaluated for variant strains exhibiting reduced susceptibility.

Mechanistic Insight into Wettability Enhancement of Lithium-Ion Batteries Using a Ceramic-Coated Layer.

The crucial issue of wettability in high-energy-density lithium-ion batteries (LIBs) has not been comprehensively addressed to date. To overcome the challenge, state-of-the-art LIBs employing a ceramic-coated separator improves the safety- and wettability-related aspects of LIBs. Here, we present a mechanistic study of the effects of a ceramic-coated layer (CCL) on electrode wettability and report the optimal position of the CCL in LIBs. The electrolyte wetting was investigated using the multiphase lattice Boltzmann method and electrochemical impedance spectroscopy for capturing the electrolyte-transport dynamics in porous electrodes and impedance spectra in pouch-type LIBs, respectively. Results indicate that the CCL caused the velocity vector to transport the electrolyte further, resulting in an increase in the wetting rate. Moreover, the location of the CCL considerably affected the wettability of the LIBs. This study provides mechanical insight into the design and fabrication of high-performance LIBs by incorporating CCLs.

Anomalous Photocurrent Reversal Due to Hole Traps in AlGaN-Based Deep-Ultraviolet Light-Emitting Diodes.

The trap states and defects near the active region in deep-ultraviolet (DUV) light-emitting diodes (LED) were investigated through wavelength-dependent photocurrent spectroscopy. We observed anomalous photocurrent reversal and its temporal recovery in AlGaN-based DUV LEDs as the wavelength of illuminating light varied from DUV to visible. The wavelength-dependent photocurrent measurements were performed on 265 nm-emitting DUV LEDs under zero-bias conditions. Sharp near-band-edge (~265 nm) absorption was observed in addition to broad (300-800 nm) visible-range absorption peaks in the photocurrent spectrum, while the current direction of these two peaks were opposite to each other. In addition, the current direction of the photocurrent in the visible wavelength range was reversed when a certain forward bias was applied. This bias-induced current reversal displayed a slow recovery time (~6 h) when the applied forward voltage was removed. Furthermore, the recovery time showed strong temperature dependency and was faster as the sample temperature increased. This result can be consistently explained by the presence of hole traps at the electron-blocking layer and the band bending caused by piezoelectric polarization fields. The activation energy of the defect state was calculated to be 279 meV using the temperature dependency of the recovery time.

Effectiveness of Regdanvimab Treatment in High-Risk COVID-19 Patients to Prevent Progression to Severe Disease.

Objective: To evaluate clinical effectiveness of regdanvimab, a monoclonal antibody agent for treating coronavirus 2019 (COVID-19). Methods: A retrospective cohort study was conducted at two general hospitals during the study period of December 2020 to May 2021. Mild COVID-19 patients with risk factors for disease progression admitted to the hospitals within seven days of symptom onset were enrolled and followed until discharge or referral. Multivariate analyses for disease progression were conducted in the total and propensity score (PS)-matched cohorts. Results: A total of 778 mild COVID-19 patients were included and classified as the regdanvimab (n = 234) and supportive care (n = 544) groups. Significantly fewer patients required O2 supplementation via nasal prong in the regdanvimab group (8.1%) than in the supportive care group (18.4%, P < 0.001). The decreased risk for O2 support by regdanvimab treatment was noticed in the multivariate analysis of the total cohort (HR 0.570, 95% CI 0.343-0.946, P = 0.030), but it was not statistically significant in the PS-matched cohort (P = 0.057). Progression to severe disease was also significantly lower in the regdanvimab group (2.1%) than in the supportive care group (9.6%, P < 0.001). The significantly reduced risk for progression to severe disease by regdanvimab treatment was observed in the analysis of both the total cohort (HR 0.262, 95% CI 0.103-0.667, P = 0.005) and PS-matched cohort (HR 0.176, 95% CI 0.060-0.516, P = 0.002). Potential risk factors for progression were investigated in the supportive care group and SpO2 < 97% and CRP elevation >1.5 mg/dL were common risk factors for O2 support and progression to severe disease. Among the patients with any of these factors, regdanvimab treatment was associated with decreased risk for progression to severe disease with slightly lower HR (HR 0.202, 95% CI 0.062-0.657, P = 0.008) than that of the total cohort. Conclusion: Regdanvimab treatment was associated with a decreased risk of progression to severe disease.

Analysis of Thermal Characteristics of AlGaN/GaN Heterostructure Field-Effect Transistors Using Micro-Raman Spectroscopy.

We investigated the heat dissipation in heterostructure field-effect transistors (HFETs) using microRaman measurement of the temperature in active AIGaN/GaN. By varying the gate structure, the heat dissipation through the gate was clearly revealed. The temperature increased to 120 °C at the flat gate device although the inserted gate increased to only 37 °C. Our results showed that the inserted gate structure reduced the self-heating effect by three times compared to the flat gate structure. Temperature mapping using micro-Raman measurement confirmed that the temperature of the near gate area was lower than that of the near drain area. This indicated that the inserted gate electrode structure effectively prohibited self-heating effects.

Light-soaking effects and capacitance profiling in Cu(In,Ga)Se2 thin-film solar cells with chemical-bath-deposited ZnS buffer layers.

We fabricated Cu(In,Ga)Se2 (CIGS) solar cells with chemical-bath deposited (CBD) ZnS buffer layers with different deposition times. The conversion efficiency and the fill factor of the CIGS solar cells reveal a strong dependence on the deposition time of CBD-ZnS films. In order to understand the detailed relationship between the heterojunction structure and the electronic properties of CIGS solar cells with different deposition times of CBD-ZnS films, capacitance-voltage (C-V) profiling measurements with additional laser illumination were performed. The light-soaking effects on CIGS solar cells with a CBD-ZnS buffer layer were investigated in detail using current density-voltage (J-V) and C-V measurements with several different lasers with different emission wavelengths. After light-soaking, the conversion efficiency changed significantly and the double diode feature in J-V curves disappeared. We explain that the major reason for the improvement of efficiency by light-soaking is due to the fact that negatively charged and highly defective vacancies in the CIGS absorber near the interface of CBD-ZnS/CIGS were formed and became neutral due to carriers generated by ultra-violet absorption in the buffer layer.

Behavior of Photocarriers in the Light-Induced Metastable State in the p-n Heterojunction of a Cu(In,Ga)Se2 Solar Cell with CBD-ZnS Buffer Layer.

We fabricated Cu(In,Ga)Se2 (CIGS) solar cells with a chemical bath deposition (CBD)-ZnS buffer layer grown with varying ammonia concentrations in aqueous solution. The solar cell performance was degraded with increasing ammonia concentration, due to actively dissolved Zn atoms during CBD-ZnS precipitation. These formed interfacial defect states, such as hydroxide species in the CBD-ZnS film, and interstitial and antisite Zn defects at the p-n heterojunction. After light/UV soaking, the CIGS solar cell performance drastically improved, with a rise in fill factor. With the Zn-based buffer layer, the light soaking treatment containing blue photons induced a metastable state and enhanced the CIGS solar cell performance. To interpret this effect, we suggest a band structure model of the p-n heterojunction to explain the flow of photocarriers under white light at the initial state, and then after light/UV soaking. The determining factor is a p+ defect layer, containing an amount of deep acceptor traps, located near the CIGS surface. The p+ defect layer easily captures photoexcited electrons, and then when it becomes quasi-neutral, attracts photoexcited holes. This alters the barrier height and controls the photocurrent at the p-n junction, and fill factor values, determining the solar cell performance.

Carrier-induced transient defect mechanism for non-radiative recombination in InGaN light-emitting devices.

Non-radiative recombination (NRR) of excited carriers poses a serious challenge to optoelectronic device efficiency. Understanding the mechanism is thus crucial to defect physics and technological applications. Here, by using first-principles calculations, we propose a new NRR mechanism, where excited carriers recombine via a Frenkel-pair (FP) defect formation. While in the ground state the FP is high in energy and is unlikely to form, in the electronic excited states its formation is enabled by a strong electron-phonon coupling of the excited carriers. This NRR mechanism is expected to be general for wide-gap semiconductors, rather than being limited to InGaN-based light emitting devices.

Synthesis of silver nanoplates by two-dimensional oriented attachment.

Synthesis of silver nanoplates was studied in the modified polyol method, where the nucleation and seed stage occurred in a poly(ethylene glycol) (PEG)-water mixture solution, and the growth stage happened in the PEG environment. The morphological evolution of nanoplates was characterized using UV, SEM, and TEM. Interestingly, plane nanostructures with unusual jagged edges were finally formed in our modified polyol method. Using TEM, we observed the medium state of fusion between two nanoplates, resulting in generating unusual jagged edges. Therefore, a novel two-dimensional oriented attachment occurred in our modified polyol method, which involves smaller nanoplates as the building blocks. Further control experiments showed that the presence of water could break this kinetic preferred reactivity, leading to the formation of nanoparticles.

Localized surface plasmon enhanced quantum efficiency of InGaN/GaN quantum wells by Ag/SiO2 nanoparticles.

Optical properties of InGaN/GaN multi-quantum-well (MQW) structures with a nanolayer of Ag/SiO2 nanoparticle (NP) on top were studied. Modeling and optical absorption (OA) measurements prove that the NPs form localized surface plasmons (LSP) structure with a broad OA band peaked near 440-460 nm and the fringe electric field extending down to about 10 nm into the GaN layer. The presence of this NP LSP electrical field increases the photoluminescence (PL) intensity of the MQW structure by about 70% and markedly decreases the time-resolved PL (TRPL) relaxation time due to the strong coupling of MQW emission to the LSP mode.

Arrays of silicon micro/nanostructures formed in suspended configurations for deterministic assembly using flat and roller-type stamps.

The ability to create and manipulate large arrays of inorganic semiconductor micro/nanostructures for integration on unconventional substrates provides new possibilities in device engineering. Here, simple methods are described for the preparation of structures of single crystalline silicon in suspended and tethered configurations that facilitate their deterministic assembly using transfer-printing techniques. Diverse shapes (e.g., straight or curved edges), thicknesses (between 55 nm and 3 µm), and sizes (areas of 4000 µm(2) to 117 mm(2) ) of structures in varied layouts (regular or irregular arrays, with dense or sparse coverages) can be achieved, using either flat or cylindrical roller-type stamps. To demonstrate the technique, printing with 100% yield onto curved, rigid supports of glass and ceramics and onto thin sheets of plastic is shown. The fabrication of a printed array of silicon p(+) -i-n(+) junction photodiodes on plastic is representative of device-printing capabilities.

Trichuris trichiura infection diagnosed by colonoscopy: case reports and review of literature.

Trichuris trichiura, commonly referred to as a whipworm, has a worldwide distribution, particularly among countries with warm, humid climates. In Korea, trichuriasis was a highly prevalent soil-transmitted helminthiasis until the 1970s. However, the nationwide prevalence decreased to 0.02% in 2004 as a result of national control activities and improvement in the socioeconomic status of Koreans. Most infected individuals have no distinct symptoms, if lightly infected. The diagnosis is typically confirmed by detection of T. trichiura eggs on examination of a stool sample; few reports have described detection of the parasite during colonoscopy. Recently, we managed 4 patients with trichuriasis who were diagnosed by detection of the parasite on colonoscopy, and we reviewed the literature on the colonoscopic diagnosis of T. trichiura in Korea. We suggest that colonoscopy might be a useful diagnostic tool, especially when infected by only a few male worms with no eggs in the stool.

Plasmon resonance changes of gold nanoparticle arrays upon modification.

Periodic Au nanoparticle arrays, fabricated using electron beam lithography, have been modified by chemical reaction in solutions having various concentrations of a reducing agent. As the nanoparticles enlarge due to the formation of additional Au nanolumps on the surface, both the position and intensity of plasmon absorbance of Au nanoparticle arrays change in proportion to the concentration of the reducing agent. Moreover, the plasmon absorbance is split into dipole and quadrupole modes as conductive connections form between the particles. Our results demonstrate that the changes in both the position and intensity of plasmon absorbance can be employed together as complementary readout values of nanosensors.

A case of Diphyllobothrium latum infection with a brief review of diphyllobothriasis in the Republic of Korea.

A case of Diphyllobothrium latum infection in a 49-year old man is described, and diphyllobothriasis latum in the Republic of Korea is briefly reviewed. An incomplete strobila of a tapeworm, 95 cm in length, without scolex and neck, was spontaneously discharged in the feces of a patient. On the basis of morphologic characteristics of the worm and eggs, the worm was identified as D. latum. The patient was successfully treated with a single dose (15 mg/kg) of praziquantel. The most probable source of infection was salmon flesh according to the past history of the patient. The first case of D. latum infection was documented in 1971, and this is the 43rd recorded case in the Republic of Korea. The 43 cases were briefly reviewed. The patientso main complaints were gastrointestinal troubles, such as mild abdominal pain, indigestion, and diarrhea, and discharge of tapeworm segments in the feces. The suspected infection sources included raw or improperly cooked flesh of fresh or brackish water fish, including the perch, mullet, salmon, and trout.

Large enhancement of fluorescence efficiency from CdSe/ZnS quantum dots induced by resonant coupling to spatially controlled surface plasmons.

Nanoengineered fluorescent response is reported from semiconductor core-shell (CdSe/ZnS) quantum dots in proximity to the surface plasmon polariton field of periodic Ag nanoparticle arrays. Tuning the surface plasmon polariton resonance to the quantum dot exciton emission band results in an enhancement of up to approximately 50-fold in the overall fluorescence efficiency, in a design where each Ag nanoparticle is interconnected by a continuous Ag thin film. Propagating modes of surface plasmon resonances have a direct impact on the fluorescence enhancement.

A study on stack configuration of continuous electrodeionization for removal of heavy metal ions from the primary coolant of a nuclear power plant.

This study investigated the production of high-purity water in the primary coolant of a nuclear power plant via the continuous electrodeionization (CEDI) process, using ion exchange resins as ion-conducting media between ion exchange membranes. The effectiveness of this method was examined with respect to the removal of heavy metals. The study was carried out on a laboratory scale with an effective area of 20 cm(2). The CEDI system was operated with a layered bed of cation exchange resins, anion exchange resins, and mixed-bed ion exchange resins. The stack configuration was designed to prevent a reaction between metal ions and hydroxide ions. The CEDI operation with the layered bed removed more than 99% of the ions at 30% of the current efficiency. The results showed that, with an inlet conductivity of 40 microScm(-1), a linear velocity of 4.17 cms(-1), and an applied current density of 17 mAcm(-2), the CEDI process yielded an outlet conductivity of 0.5 microScm(-1), thereby preventing the precipitation of metal ions. This study therefore successfully demonstrated the feasibility of the CEDI operation for the removal of heavy metals at a very low concentration.