81 research outputs found
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Department of Chemical EngineeringColloidal semiconductor nanocrystals, also known as nanocrystal quantum dots(QDs), are being studied intensively as future optoelectronic materials due to its solution processing and outstanding optical properties. Among them, perovskite quantum dots(PeQDs) have a wide emission range from near-infrared to ultraviolet by controlling its composition, and are highly luminescent with narrow FWHM by easier synthesize process. Therefore, perovskite nanocrystals are receiving attention as a high-quality optoelectric device material.
However, there is a drop of quantum yield at specific composition includes chloride anion, which are covering blue to ultraviolet emission range. Due to the drop of quantum yield, high-quality blue LED with perovskite still not reported.
In this work, I report the highly luminescent chlorine-free blue perovskite nanoplatelets(PeNPLs) as pure bromide halide composition, which was synthesized by supporting of saturated amine ligand. The thickness of PeNPLs was controlled by reaction parameters such as reaction time and reaction temperature. Also, thickness homogeneity was secured by ligand assisted solubility adjustment method after synthesis. Through this two-step thickness control, photoluminescence properties of the synthesized PeNPLs could be easily concentrated on specific wavelength emission while the full width half maximum (FWHM) could be decreased under 22 nm. Furthermore, the time dependent stability of nanoplatelets increase through close-packed ligands which are less steric hindered. Lastly, blue light emitting diodes (LED) with surface-treated perovskite nanoplatelets could have higher efficiency than mixed-halide perovskite nanocrystal. It was possible by emitting material???s property improvement and close-stacked nanoplatelets arrange. I strongly believe that this work would be the basic approach of perovskite nanoplatelet device.ope
Puget Sound Dissolved Oxygen Modeling Study: Development of an Intermediate-Scale Hydrodynamic Model
The Washington State Department of Ecology contracted with Pacific Northwest National Laboratory to develop an intermediate-scale hydrodynamic and water quality model to study dissolved oxygen and nutrient dynamics in Puget Sound and to help define potential Puget Sound-wide nutrient management strategies and decisions. Specifically, the project is expected to help determine 1) if current and potential future nitrogen loadings from point and non-point sources are significantly impairing water quality at a large scale and 2) what level of nutrient reductions are necessary to reduce or dominate human impacts to dissolved oxygen levels in the sensitive areas. In this study, an intermediate-scale hydrodynamic model of Puget Sound was developed to simulate the hydrodynamics of Puget Sound and the Northwest Straits for the year 2006. The model was constructed using the unstructured Finite Volume Coastal Ocean Model. The overall model grid resolution within Puget Sound in its present configuration is about 880 m. The model was driven by tides, river inflows, and meteorological forcing (wind and net heat flux) and simulated tidal circulations, temperature, and salinity distributions in Puget Sound. The model was validated against observed data of water surface elevation, velocity, temperature, and salinity at various stations within the study domain. Model validation indicated that the model simulates tidal elevations and currents in Puget Sound well and reproduces the general patterns of the temperature and salinity distributions
Analysis of Flood Hazards for the Materials and Fuels Complex at the Idaho National Laboratory Site
Researchers at Pacific Northwest National Laboratory conducted a flood hazard analysis for the Materials and Fuels Complex (MFC) site located at the Idaho National Laboratory (INL) site in southeastern Idaho. The general approach for the analysis was to determine the maximum water elevation levels associated with the design-basis flood (DBFL) and compare them to the floor elevations at critical building locations. Two DBFLs for the MFC site were developed using different precipitation inputs: probable maximum precipitation (PMP) and 10,000 year recurrence interval precipitation. Both precipitation inputs were used to drive a watershed runoff model for the surrounding upland basins and the MFC site. Outflows modeled with the Hydrologic Engineering Centers Hydrologic Modeling System were input to the Hydrologic Engineering Centers River Analysis System hydrodynamic flood routing model
Nanomechanical In Situ Monitoring of Proteolysis of Peptide by Cathepsin B
Characterization and control of proteolysis of peptides by specific cellular protease is a priori requisite for effective drug discovery. Here, we report the nanomechanical, in situ monitoring of proteolysis of peptide chain attributed to protease (Cathepsin B) by using a resonant nanomechanical microcantilever immersed in a liquid. Specifically, the detection is based on measurement of resonant frequency shift arising from proteolysis of peptides (leading to decrease of cantilever's overall mass, and consequently, increases in the resonance). It is shown that resonant microcantilever enables the quantification of proteolysis efficacy with respect to protease concentration. Remarkably, the nanomechanical, in situ monitoring of proteolysis allows us to gain insight into the kinetics of proteolysis of peptides, which is well depicted by Langmuir kinetic model. This implies that nanomechanical biosensor enables the characterization of specific cellular protease such as its kinetics
Performance of the combined models of Pediatric Risk of Admission scores I and II, and C-reactive protein for prediction of hospitalization in febrile children who visited the emergency department
Purpose To study the performance of the combined models of Pediatric Risk of Admission (PRISA) scores I and II and C-reactive protein (CRP) for prediction of hospitalization in febrile children who visited the emergency department. Methods We reviewed febrile children aged 4 months - 17 years who visited a tertiary hospital emergency department between January and December 2017. White blood cell count, CRP concentration, the PRISA scores, and systemic inflammatory response syndrome score were calculated. We compared areas under the curves (AUCs) of the admission decision support tools for hospitalization using receiver operating characteristic curve analysis. Results Of 1,032 enrolled children, 423 (41.0%) were hospitalized. CRP and the PRISA scores were significantly higher in the hospitalization group than in the discharge group (all P < 0.001). Among the individual tools, CRP showed the highest AUC (0.69; 95% confidence interval [CI], 0.66-0.72). AUC was 0.71 (95% CI, 0.69-0.74) for the combined model of the PRISA I score and CRP, and 0.71 (95% CI, 0.68-0.74) for that of the PRISA II score and CRP. The AUC of PRISA score I and CRP combined was significantly higher than that of isolated CRP (P=0.048). Conclusion The combined model of the PRISA I score and CRP may be useful in predicting hospitalization of febrile children in emergency departments
Ferroelectric behavior in nominally relaxor lead lanthanum zirconate titanate thin films prepared by chemical solution deposition on copper foil
Therapeutic effect of ascorbic acid on dapsone-induced methemoglobinemia in rats
Objective Dapsone (diaminodiphenyl sulfone, DDS) is currently used to treat leprosy, malaria, dermatitis herpetiformis, and other diseases. It is also used to treat pneumocystis pneumonia and Toxoplasma gondii infection in HIV-positive patients. The most common adverse effect of DDS is methemoglobinemia from oxidative stress. Ascorbic acid is an antioxidant and reducing agent that scavenges the free radicals produced by oxidative stress. The present study aimed to investigate the effect of ascorbic acid in the treatment of DDS induced methemoglobinemia. Methods Male Sprague-Dawley rats were divided into three groups: an ascorbic acid group, a methylene blue (MB) group, and a control group. After DDS (40 mg/kg) treatment via oral gavage, ascorbic acid (15 mg/kg), MB (1 mg/kg), or normal saline were administered via tail vein injection. Depending on the duration of the DDS treatment, blood methemoglobin levels, as well as the nitric oxide levels and catalase activity, were measured at 60, 120, or 180 minutes after DDS administration. Results Methemoglobin concentrations in the ascorbic acid and MB groups were significantly lower compared to those in the control group across multiple time points. The plasma nitric oxide levels and catalase activity were not different among the groups or time points. Conclusion Intravenous ascorbic acid administration is effective in treating DDS-induced methemoglobinemia in a murine model
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Simple, Scalable Proteomic Imaging for High-Dimensional Profiling of Intact Systems
Combined measurement of diverse molecular and anatomical traits that span multiple levels remains a major challenge in biology. Here, we introduce a simple method that enables proteomic imaging for scalable, integrated, high-dimensional phenotyping of both animal tissues and human clinical samples. This method, termed SWITCH, uniformly secures tissue architecture, native biomolecules, and antigenicity across an entire system by synchronizing the tissue preservation reaction. The heat- and chemical-resistant nature of the resulting framework permits multiple rounds (>20) of relabeling. We have performed 22 rounds of labeling of a single tissue with precise co-registration of multiple datasets. Furthermore, SWITCH synchronizes labeling reactions to improve probe penetration depth and uniformity of staining. With SWITCH, we performed combinatorial protein expression profiling of the human cortex and also interrogated the geometric structure of the fiber pathways in mouse brains. Such integrated high-dimensional information may accelerate our understanding of biological systems at multiple levels.Simons Foundation. Postdoctoral FellowshipLife Sciences Research FoundationBurroughs Wellcome Fund (Career Award at the Scientific Interface)Searle Scholars ProgramMichael J. Fox Foundation for Parkinson's ResearchUnited States. Defense Advanced Research Projects AgencyNational Institutes of Health (U.S.) (1-U01-NS090473-01
Multiplexed and scalable super-resolution imaging of three-dimensional protein localization in size-adjustable tissues
The biology of multicellular organisms is coordinated across multiple size scales, from the subnanoscale of molecules to the macroscale, tissue-wide interconnectivity of cell populations. Here we introduce a method for super-resolution imaging of the multiscale organization of intact tissues. The method, called magnified analysis of the proteome (MAP), linearly expands entire organs fourfold while preserving their overall architecture and three-dimensional proteome organization. MAP is based on the observation that preventing crosslinking within and between endogenous proteins during hydrogel-tissue hybridization allows for natural expansion upon protein denaturation and dissociation. The expanded tissue preserves its protein content, its fine subcellular details, and its organ-scale intercellular connectivity. We use off-the-shelf antibodies for multiple rounds of immunolabeling and imaging of a tissue's magnified proteome, and our experiments demonstrate a success rate of 82% (100/122 antibodies tested). We show that specimen size can be reversibly modulated to image both inter-regional connections and fine synaptic architectures in the mouse brain.United States. National Institutes of Health (1-U01-NS090473-01
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