A deep understanding of defects in terms of stability and optoelectronic properties is essential for optimizing semiconductor devices. For faster and more accurate investigation of defects, we ...examined whether the hybrid density functional theory calculation can be performed cost-effectively by downsampling the k-point meshes for Fock exchange potential. The P dopant and Si self-interstitial defects were used to check the convergence of the total energy. Our calculation shows that the defect properties like the formation energy and the charge transition levels can be cost-effectively calculated by using downsampled k-point meshes. We also investigated the intrinsic vacancy defects and obtained consistent results with previous studies.
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The morphology of heterostructured semiconductor nanocrystals (h-NCs) dictates the spatial distribution of charge carriers and their recombination dynamics and/or transport, which are the main ...performance indicators of photonic applications utilizing h-NCs. The inability to control the morphology of heterovalent III-V/II-VI h-NCs composed of heavy-metal-free elements hinders their practical use. As a case study of III-V/II-VI h-NCs, the growth control of ZnSe epilayers on InP NCs is demonstrated here. The anisotropic morphology in InP/ZnSe h-NCs is attributed to the facet-dependent energy costs for the growth of ZnSe epilayers on different facets of InP NCs, and effective chemical means for controlling the growth rates of ZnSe on different surface planes are demonstrated. Ultimately, this article capitalizes on the controlled morphology of InP/ZnSe h-NCs to expand their photophysical characteristics from stable and pure emission to environment-sensitive one, which will facilitate their use in a variety of photonic applications.
Optimal pain management after insertion of a central venous catheter in children remains unclear.
This study aimed to evaluate the effects of a selective supraclavicular nerve block on postoperative ...analgesia in pediatric patients undergoing hickman catheter or chemoport insertion.
Fifty patients aged 3-18 years scheduled for elective Hickman or chemoport insertion were randomized into two groups of 25 each: one group received an ultrasound-guided selective supraclavicular nerve block with 0.1 mL/kg of 0.5% ropivacaine (SSCNB group), and the other group did not receive a nerve block (control group). The primary outcome was the postoperative Wong-Baker Faces Pain Rating Scale score measured between 10 and 30 min after surgery. Secondary outcomes included pain scores at 1, 3, and 24 h after the surgery, block-related complications, length of stay in the postanesthesia care unit, postoperative analgesic consumption, and time to first analgesic use 24 h after surgery.
The worst pain score within 30 min in the recovery room was significantly lower in the SSCNB group compared to the control group (6 5-7 vs. 3 2-4; median difference, -3; 95% CI, -4 to -1; p < .001). Pain scores at 1, 3, and 24 h after surgery were also significantly lower in the SSCNB group. The need for both opioid and non-opioid analgesics in the postoperative period was significantly lower in the SSCNB group (36.0% vs. 0%; p = .002 and 44.0% vs. 16.0%; mean difference, -28%; 95% CI, -56 to 0.19; p = .033, respectively), while other secondary outcomes were not significantly different between the two groups.
Ultrasound-guided SSCNB is an effective method for managing postoperative pain in children undergoing Hickman catheter or chemoport insertion, reducing the need for analgesics within 24 h after surgery.
The electronic structure and related optical properties of an emerging thin-film photovoltaic material CH3NH3PbBr3 are studied. A block-shaped α-phase CH3NH3PbBr3 single crystal with the natural ...⟨100⟩ surface is synthesized solvothermally. The room-temperature dielectric function ε = ε1 + iε2 spectrum of CH3NH3PbBr3 is determined by spectroscopic ellipsometry from 0.73 to 6.45 eV. Data are modeled with a series of Tauc–Lorentz oscillators, which show the absorption edge with a strong excitonic transition at ∼2.3 eV and several above-bandgap optical structures associated with the electronic interband transitions. The energy band structure and ε data of CH3NH3PbBr3 for the CH3NH3 + molecules oriented in the ⟨111⟩ and ⟨100⟩ directions are obtained from first-principles calculations. The overall shape of ε data shows a qualitatively good agreement with experimental results. Electronic origins of major optical structures are discussed.
The inconsistent vitality and efficiency of plant growth promoting bacteria (PGPB) are technical limitations in the application of PGPB as biofertilizer. To improve these disadvantages, we examined ...the potential of micro Dielectric Barrier Discharge (DBD) plasma to enhance the vitality and functional activity of a PGPB, Bacillus subtilis CB-R05. Bacterial multiplication and motility were increased after plasma treatment, and the level of a protein involved in cell division was elevated in plasma treated bacteria. Rice seeds inoculated with plasma treated bacteria showed no significant change in germination, but growth and grain yield of rice plants were significantly enhanced. Rice seedlings infected with plasma treated bacteria showed elevated tolerance to fungal infection. SEM analysis demonstrated that plasma treated bacteria colonized more densely in the broader area of rice plant roots than untreated bacteria. The level of IAA (Indole-3-Acetic Acid) and SA (Salicylic Acid) hormone was higher in rice plants infected with plasma treated than with untreated bacteria. Our results suggest that plasma can accelerate bacterial growth and motility, possibly by increasing the related gene expression, and the increased bacterial vitality improves colonization within plant roots and elevates the level of phytohormones, leading to the enhancement of plant growth, yield, and tolerance to disease.
Abstract
Colloidal Ag(In,Ga)S
2
nanocrystals (AIGS NCs) with the band gap tunability by their size and composition within visible range have garnered surging interest. High absorption cross-section ...and narrow emission linewidth of AIGS NCs make them ideally suited to address the challenges of Cd-free NCs in wide-ranging photonic applications. However, AIGS NCs have shown relatively underwhelming photoluminescence quantum yield (PL QY) to date, primarily because coherent heteroepitaxy has not been realized. Here, we report the heteroepitaxy for AIGS-AgGaS
2
(AIGS-AGS) core-shell NCs bearing near-unity PL QYs in almost full visible range (460 to 620 nm) and enhanced photochemical stability. Key to the successful growth of AIGS-AGS NCs is the use of the Ag-S-Ga(OA)
2
complex, which complements the reactivities among cations for both homogeneous AIGS cores in various compositions and uniform AGS shell growth. The heteroepitaxy between AIGS and AGS results in the Type I heterojunction that effectively confines charge carriers within the emissive core without optically active interfacial defects. AIGS-AGS NCs show higher extinction coefficient and narrower spectral linewidth compared to state-of-the-art heavy metal-free NCs, prompting their immediate use in practicable applications including displays and luminescent solar concentrators (LSCs).
Obtaining high performance of hematite (α-Fe2O3) in a photoelectrochemical (PEC) water splitting cell is a challenging task because of its poor electrical conductivity and extremely short carrier ...lifetime. Here, we introduce a new hydrothermal method, called gap hydrothermal synthesis (GAP-HS), to obtain textured hematite thin films with an outstanding PEC water oxidation performance. GAP-HS proceeds in a precursor-solution-filled narrow gap to induce an anisotropic ion supply. This gives rise to an interesting phenomenon associated with the growth of nanomaterials that reflect the texture of the used substrates. Also, GAP-HS causes the preferential growth of hematite crystal along the 110 direction, leading to improved electrical conductivity within the (001) basal plane. The hematite thin films obtained via GAP-HS exhibit a very high photocurrent of more than 1.3 mA cm–2 at 1.23 V with respect to the reversible hydrogen electrode with 550 °C annealing only. It is the highest photocurrent, to the best of our knowledge, obtained for the hydrothermally synthesized pristine hematite photoanode. Because the low-temperature annealing allows avoiding of substrate deformation, the hematite thin films obtained via GAP-HS are expected to be advantageous for tandem-cell configuration.
Background
The light reflex, which reflects central nervous system dysfunction, can also be affected by anesthetic agents.
Aims
We evaluated whether these effects differed according to the anesthetic ...agent in pediatric patients.
Methods
Twenty children aged 3–12 years who were scheduled to undergo elective surgery under general anesthesia were randomly allocated to propofol and sevoflurane groups and underwent pupillometric assessments at five points during anesthesia: T1, after confirming loss of consciousness; T2, after endotracheal intubation; T3, at the time of skin incision; T4, 1 h after skin incision; and T5, before endotracheal extubation. The primary outcome was the Neurological Pupil index at T4, and the secondary outcomes were other pupillometric parameters, including pupil diameter, percentage of change in pupil diameter, dilation velocity, and constriction velocity.
Results
At T4, the Neurological Pupil index was significantly lower in the sevoflurane group (median difference, 0.30; 95% CI, 0.00 to 0.70; p = .036). Furthermore, the Neurological Pupil index at all time points was lower in the sevoflurane group. The time‐and‐group interaction effects on constriction velocity and dilation velocity were significantly different F(1, 4) = 16.68, p = .002; F(1, 4) = 14.78, p = .008, respectively but were not different on the Neurological Pupil index, pupil diameter, and percentage of change in pupil diameter. No intergroup differences were observed in the baseline characteristics, the flow rate of remifentanil at each time point, and total infused remifentanil.
Conclusion
The Neurological Pupil index value in pediatric patients under general anesthesia is affected by the anesthetic agent used; this factor requires consideration in evaluations of the Neurological Pupil index during general anesthesia.
A chemical stability between polysulfides and electrolyte is considered to be crucial to achieving good electrochemical performance of lithium–sulfur (Li–S) batteries since long-chain polysulfides ...which dissolve easily into common electrolyte can trigger substantial electrolyte decomposition due to their nucleophilic nature. In this work, we investigated the chemical reactivity of polysulfides toward carbonate-based electrolytes through a simple probing experimental method and found that the polysulfides react with carbonate-based electrolytes via a nucleophilic addition or substitution reaction leading to a sudden capacity fading of lithium sulfur cells by loss of active sulfur. This study strongly suggests that electrolytes for Li–S system should not possess an electrophilic functionality to avoid undesired chemical reaction with polysulfides. In addition, we show that the methodology developed in this work for the verification of chemical stability between polysulfides and electrolyte can be widely applicable to screening other potential electrolyte candidates.
Heavy metal contamination caused by abandoned mines is a serious environmental problem in Korea. Acid mine drainage (AMD) contains various toxic heavy metals as well as dissolved iron and aluminum ...that contaminate downstream areas. Recent research on the removal and recovery of metals in AMD has attempted to solve environmental problems related to AMD. In a previous study, we reported that dissolved Fe, Al, Cu, and Zn/Ni can be recovered from AMD via selective precipitation. However, the recovery process consumed too many chemicals, both neutralizing and oxidizing agents. To solve this problem, the current intensity study investigated the potential of electrochemical methods to produce oxidizing and neutralizing agents that will decrease the need for chemicals. Fe(II) in anolyte was directly oxidized to Fe(III) on the electrode surface, not by oxidants. Anode material and current intensity influence oxidation reaction rate. Graphite anode resulted in the highest oxidation rate, and higher current intensity enhanced oxidation rate. In the connecting media experiments, the cation exchange membrane (CEM) and anion exchange membrane (AEM) demonstrated high loss of Fe (about 40∼50%) caused by precipitation on the membrane surface and in the catholyte. The Fe loss used for salt bridge (SB) was about 10%. The catholyte contained a high concentration of hydroxide generated by the cathodic reaction that can be used as a neutralizing agent. The neutralizing agent produced by electrochemical reactions can be used to selectively recover dissolved metals. Additionally, the use of solar cell reduced energy consumption. Based on the results, it is possible to oxidize Fe(II) to Fe(III) while producing neutralizing agents for selective recovery of dissolved metals from AMD.
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