bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ruthenium-Modified Sensitive NO Sensors: Quantifying Nitric Oxide in the Pathobiology of Cystic Fibrosis
Authors: Bose Tiyash , Bayachou Mekki 
Published: February 2020

This is a preliminary work towards preparing a device capable to measure nitric oxide levels in a cystic fibrosis cell line model. It has been found that exhaled NO levels remains unchanged or reduced in cystic fibrosis patients unlike other inflammatory lung diseases like asthma where it increases. However it is not clear whether the lower NO levels in cystic fibrosis correlate with lowered production of this metabolite in the bronchial epithelium. We will present preliminary results of our ruthenium oxide modified combined electrodes and how they can be applied to the study of cystic fibrosis at the cellular level.
In this work, we explore the performance of combined reference/working electrodes modified with ruthenium oxide and Poly(3,4-ethylenedioxythiophene) (PEDOT) in the detection of nitric oxide with the goal to measure nitric oxide at the level of single or collective cultured cells. The synergistic effect of the electrocatalytic activity of ruthenium oxide and the enhanced surface area for catalytic activity provided by the polymer greatly enhanced the analytical performance of our sensors in terms of sensitivity, selectivity and stability. With the incorporation of a layer by layer method of electrodeposition we attained a normalized sensitivity of 8.38E-4 pA/nM/μM2 and 1.16E-2 pA/nM/μM2 towards NO in the linear range of 0.2-1.6 mM and 2-16 nM respectively, at an applied potential of 0.8 V vs Ag/AgCl and a detection limit in the vicinity of 500 pM. In order to improve the selectivity of our sensors we coated the surface with nafion and also an ionic liquid composite and lowered the applied to 0.6 V vs. Ag/AgCl. We also measured the response to NO using Differential Pulse Amperometry to further decrease response from biological interferents especially nitrite and ascorbic acid.
Corrosion of Carbon Steel Wire Roads Containing Various Sulfur Content in Sour Solutions
Authors: Kim Su-Won , Park Chan-Jin 
Published: February 2020

High strength carbon steel wire roads have been widely used in armor cables for offshore oil drilling plants. However, the materials can undergo some corrosions and hydrogen related damages such as hydrogen induced cracking (HIC) and sulfide stress cracking (SSC). In particular, it has been reported that HIC is highly influenced by content of MnS containing inside the steels. However, effects of sulfur content on the corrosion of carbon steel wire rod have scarcely been reported systematically. In this study, the effects of sulfur and propagation of corrosion in carbon steel wire rod were investigated in sour solutions with various pH.
The carbon steel wire rods containing various sulfur content were used. All electrochemical tests were conducted using three-electrode system with a saturated calomel electrode (SCE) as the reference electrode and a Pt wire as the counter electrode. In addition, acetic acid based solution containing 95% CO2 and 5% H2S were used to adjust pH in the range of 2.5-6.5 at the room temperature for corrosion tests. Before testing, the carbon steel wire words were polished by abrasive papers and then washed with ethanol, and deionized water. The overall corrosion behaviors and corrosion rate of the samples were analyzed using potentiodynamic tests. In addition, the HIC characteristic of the steels was investigated by immersing the samples in the solution followed by observing the crack propagation inside the samples. Surface morphologies of the samples after tests were also observed by optical microscope (OM) and scanning electron microscope (SEM).
The corrosion current densities (icorr
) of carbon steel increased with the increasing in sulfur contents in the steels. Further, from the polarization curves, it is observed that cathodic current density increased with sulfur content in steels. It is noticeable that the anodic current density rarely changes. This result indicates that the cathodic hydrogen evolution process on the surface of the steels was promoted by S content inside the steels. In addition, the samples without applied stress showed the internal macro-cracks in cross sections in pH 2.5~5.1, while only small micro-cracks were found in solution pH 5.1~6.5. The length of crack increased with increasing sulfur content except in the solution with pH 5.1~6.5. In particular, the micro-cracks by HIC appeared to initiate around inclusions. Some tracing of the cracks will be shown in this presentation.
Signal Amplification of a Universal Four-Way Junction Based Nucleic Acid Sensor through Modification of Electrochemical Technique Parameters
Authors: Mills Dawn M , Chumbimuni-Torres Karin Y. 
Published: February 2020

Here, we report the characterization of a four-way junction (4J) universal electrochemical sensor that consists of an electrode-immobilized DNA stem-loop (SL) probe and two adaptor strands (m and f). The “m” adaptor strand was labeled with a methylene blue (MeB) redox marker. The adaptor strands hybridize to the DNA SL probe and target nucleic acid to form a 4J structure. In this orientation the MeB is in close proximity to the electrode’s surface thus enabling its reduction and subsequent electrochemical signal. The experimental timing for immobilization of the DNA SL probe and hybridization with adaptor strands and miRNA-122 was investigated. In addition, the density of the DNA SL probe coverage was evaluated using chronocoulometry to determine the ideal concentration of immobilized DNA SL probe. The sensor performance was investigated using cyclic voltammetry (CV), alternating current voltammetry (ACV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV). Specifically, a single parameter from each voltammetric technique was modified to evaluate the sensor’s response. The DNA SL probe demonstrated an efficient immobilization after 30 minutes and optimal hybridization occurred at 1.5 hours. The 4J sensor was characterized with ACV at a frequency range from 1 to 5000 Hz and the current increased from 1 to 600 Hz where the threshold of the sensor was reached, followed by a drastic decrease in signal at higher frequencies. The 4J sensor was also characterized with SWV at frequencies ranging from 1 to 5000 Hz and exhibited an increase in signal from 1 to 1500 Hz, where the signal stabilized until reaching the threshold frequency of 4000 Hz, where the current then began to decrease. CV was used to evaluate the sensor’s performance at scan rates ranging from 0.1 to 800 V/s. The peak separation increased at faster scan rates (529 mV) and the signal was saturated after 500 V/s. Finally, the sensor performance was monitored using DPV at pulse widths ranging from 1 to 100 ms. The current was highest at short pulse widths (1 ms) and the current decreased rapidly as the pulse width was increased. Amplification of the 4J sensor was achieved by modifying a specific parameter for each electrochemical technique which can provide insight into the sensor performance to facilitate lower limits of detection of nucleic acids.
Synthesis of Photocatalytic Nanocomposite Biomaterials for Enhanced Water Filtration Application
Authors: Murray Jacob , Senese Elizabeth , Rech Jeromy J , Keleher Jason J 
Published: February 2020

Clean and drinkable water is a critical necessity for all human and economic development; unfortunately, millions of people do not have access to potable water, resulting in the death of over 2 million children every year. Over the past decade, emphasis has been placed on the synthesis and design of photocatalytic nanocomposites to enhance the chemical degradation of organic pollutants as a cost effective vehicle for clean water production. Amongst the many semiconducting nanoparticles explored in literature, TiO2has stood out for its favorable physiochemical properties, low toxicity, easy availability, high stability, and low cost. When TiO2is irradiated by ultraviolet light, there is creation an electron-hole pair which provides sites for effective reduction or oxidization of the pollutant, converting the pollutant to carbon dioxide, water, and mineral acids. One major shortcoming of TiO2 is related to the efficiency of these systems to harness the entire solar spectrum; therefore, a main focus of this work is the modification of the TiO2 nanoparticles to increase the photon capture efficiency in the visible light region. Of the various possible functionalization pathways, this work focuses on dye sensitization, noble metal deposition, and silane functionalization as well as understanding the synergy between all three. When looking at the rate of remediation of a organic dye pollutant in a simulated sunlight environment, the functionalized particles completely remediated an organic dye pollutant. These functionalized nanoparticles were then deposited into a cellulose matrix of highly absorbent beads in order to prepare a nanocomposite. Results show there is a decrease in the chemical degradation of the pollutant when in the nanocomposite, but a significant increase in a physio-absorption capacity, thus maintaining the rate of total remediation. In addition, the binding interaction between the dye and the particle is a major component in chemical degradation; an aminosilane can be covalently added to the surface of the nanoparticle, and increase the ability of various dyes to adhere to the surface of the TiO2. The incorporation of Ag-functionalized nanocomposites resulted in a synergistic antimicrobial effect, which eliminated both E. coli and S. aureus from the water sample, in addition to increasing the photochemical degradation rate. The specific aim of this work was to create functionalized TiO2 particles with silane groups, organic dyes, and Ag, for the incorporation into a photocatalytic biomimetic nanocomposite membrane which utilizes sunlight to degrade pollutants and inhibit the growth of deadly bacteria.
Organic Single-Crystal Transistors Based on DBT3 Derivatives
Authors: Onozuka Tomoya , Tsutsui Masanori , Okamoto Kazuo , Kunugi Yoshihito 
Published: February 2020

Heteroacenes that contain chalcogenophene have been actively investigated as semiconducting materials because they are more stable in air than acenes and various chemical modifications of the compounds are possible. While there have been many attempts to combine benzene with thiophene rings to produce higher-performance materials, only a few derivatives are known to show high mobilities above 1 cm2 /Vs. Also OFETs of high performance have been often achieved by using expanded heteroaromatic of π-conjugated including thiophene oligomers as the semiconducting materials.
In this work, we synthesize new type of fused chalcogenophene based transistor materials, 54DBTTT and 8-67DBTTT (Fig. 1), and investigate the characterization of organic single-crystal transistors based on the newly developed materials.
We made organic single crystals of 54DBTTT and 8-67DBTTT by physical vapor transport (PVT) and drop-cast method. We used an n
+-doped Si wafer with 220 nm thickness thermally grown SiO2, which was covered with a thin film (ca. 27.8 nm) of CYTOP insulator or a thin film (ca. 30 nm) of poly(methyl methacrylate) (PMMA) insulator. Source and drain electrodes were painted with a colloidal graphite paste. The field-effect mobility (μ) of the OFET devices were measured under vacuum from the saturation regime according to the equation: I
d=μC
i(W/2L)(V
g-V
th)2, where C
i is capacitance of the insulator, V
d and V
th are the gate and threshold voltages, respectively.
To investigate the molecular conformation and stacking of the molecules in the crystal states, single-crystal X-ray analysis was performed. In contrast to the herringbone structure 54DBTTT, 8-67DBTTT molecules exhibit a two-dimensional brick-wall packing arrangement (Fig. 2).
Organic single-crystal transistors based on DBTTT derivatives showed typical p-channel FET characteristic. The best field-effect mobility of 0.3 cm2 /Vs was obtained for 54DBTTT based single-crystal device with a CYTOP covered Si/SiO2 substrate. On the other hand, the mobility for the 8-67DBTTT based transistor was 8.1x10-3 cm2 /Vs. As shown above, molecular packing structure of the 8-67DBTTT is brick-wall packing. Acoording to the Fig. 2(d) alkyl chain placed between the DBTTT cores, which is not preferable to the high performance OFET device.

Figure 1
(Invited) Upconverting Fluoride Nanocrystals - Synthesis and Optical Properties
Authors: Noculak Agnieszka , Podhorodecki Artur 
Published: February 2020

Over the past decade, high-quality lanthanide doped upconverting nanocrystals (UPCNCs) have been successfully synthesized with the rapid development of nanotechnology. Several materials (i.e. CaF2, NaYF4, NaGdF4) have been successfully applied so far as potential matrix for Yb3+-RE3+combinations, where the low crystal field symmetry and low phonon frequency are the main factors defining the best matrix selection. These materials have already found several potential applications in biology, medicine as well as in photovoltaics and photocatalysis – as the most common examples. However, to change the commercial potential of UPCNCs to real devices still a several problems must be solved, where week emission quantum efficiency (EQE typically < 2%) is one of the most important one. The EQE is directly related to other challenges in this field: growth of small size <10 nm UPCNCs, UPCNCs shape and architecture control and control of UPCNCs surface properties. To solve all abovementioned problems the correlation between technological, morphological and physical parameters is needed. This is however a difficult task because the system itself is very complicated and consist number of correlated parameters. Thus, still a better understanding of physical processes responsible for the optical properties of UPCNCs in needed to bring this fascinating material to commercial use.
In this work, we will discuss synthesis and optical properties of NaGdF4-based up-converting nanocrystals. We will discuss how to control size, shape and core-shell architecture of lanthanide doped NaGdF4 nanocrystals focusing mainly on Yb-Er co-doping. We will discuss how doping influencing the nanocrystals size, shape and their optical properties (Fig.1.). This will be done based on experimental results obtained from photoluminescence (PL) measurements, PL-excitation spectroscopy, PL-decay measurements, microscopic imaging and structural data obtained from HRTEM and XRD. Our conclusions will be supported by results obtained from numerical Monte Carlo modeling used to model the kinetic properties of nanocrystals emission and to model the ions distribution within the nanocrystals volume. Finally, based on our work on nanocrystals surface functionalization and their toxicity tests we will briefly discuss the potential use of UPCNCs in biology and medicine.
Figure 1. ß-NaGdF4:Yb, Er nanocrystals with different shapes and architectures.

Figure 1
(Invited) Plasmonic Hot Carrier Injection in Wide Bandgap Nitride Semiconductors
Authors: Narang Prineha 
Published: February 2020

Despite more than a decade of intensive scientific exploration, new plasmonic phenomena continue to be discovered, including quantum interference of plasmons, observation of quantum coupling of plasmons to single particle excitations, and quantum confinement of plasmons in single-nm scale plasmonic particles. Simultaneously, plasmonic structures find widening applications in integrated nanophotonics, biosensing, photovoltaic devices, single photon transistors and single molecule spectroscopy. Decay of surface plasmons to hot carriers is a new direction that has attracted considerable fundamental and application interest, yet a theoretical understanding of ultrafast plasmon decay processes and the underlying microscopic mechanisms remain incomplete.
Recently we analyzed the quantum decay of surface plasmon polaritons and found that the prompt distribution of generated carriers is extremely sensitive to the energy band structure of the plasmonic material. A theoretical understanding of plasmon-driven hot carrier generation and relaxation dynamics at femtosecond timescales is presented here. We report the first ab initio calculations of phonon-assisted optical excitations in metals, which are critical to bridging the frequency range between resistive losses at low frequencies and direct interband transitions at high frequencies. We also present calculations of energy-dependent lifetimes and mean free paths of hot carriers, accounting for electron-electron and electron-phonon scattering, lending insight towards transport of plasmonically-generated carriers at the nanoscale. We will discuss calculations for multiplasmon and nonlinear processes in the ultrafast regime from the mid-IR to visible and in different geometries. Employing a Feynman diagram approach here has been critical to determine the relevant processes.
Based on these theoretical predictions, we designed a solid-state system with wide-bandgap semiconductors and studied the photocurrent generated upon plasmon decay across the extended UV and visible regime for different metals and plasmonic structures. Direct comparison with ab-initio calculations allow us to assess the contribution of direct and indirect transitions and identify guidelines for engineering the generation of plasmonic hot-carriers in the UV-VIS regime.
Reversible Magnetization Modulation in Ordered Mesoporous Mixed Metal Oxide Thin Films By Double Layer Charging and Topotactic Lithium Insertion
Authors: Reitz Christian , Brezesinski Torsten 
Published: February 2020

Mesostructured metal oxide thin films have received much attention in recent years. The primary reason for this is the fact that many such materials have been shown to outperform their bulk counterparts. Energy storage and conversion is one of the fields where this is very evident. Advances in polymer templating over the past 10 years have enabled the preparation of various thin film materials with cubic and 2D-hexagonal pore structures and different ordering lenghts.[1] Their formation relies in principle on the coassembly of either sol-gel precursors or preformed building blocks with an amphiphilic polymer structure-directing agent. Despite the progress made so far, complex metal oxides (mixed metal oxides) often exhibit an ill-defined mesoporous morphology after removal of the polymer template and thermally-induced crystallization because of their limited stability.
Here, we describe the evaporation-induced self-assembly (EISA)[2] synthesis of cubic mesoporous mixed metal oxide thin films with >15 nm diameter pores and nanocrystalline walls by using a large polyisobutylene-block-poly(ethylene oxide) diblock copolymer. We focus specifically on perovskite-type La1–x
Sr
x
MnO3 (LSMO) and La1–y
Ca
y
MnO3 (LCMO) as well as spinel-type LiFe5O8. These materials were characterized by various state-of-the-art techniques, including electron microscopy, GISAXS, RBS, XRD and XPS, and were found to be of high quality after calcination at elevated temperatures. For LSMO and LCMO, we show that the charge carrier density, and therefore the magnetization, can be modulated through double layer charging (i.e., electrostatic hole- or electron-doping).[3] Magnetization modulation values of up to 10% have been achieved, the highest thus far reported for electrolyte-gated mixed-valence manganese oxides. Apart from that, we show that the room temperature magnetization of LiFe5O8 can be tuned by topotactic insertion/extraction of Li-ions into/from the spinel lattice and provide insights into the mechanism. Both processes allow for control of magnetism, are highly reversible, and strongly benefit from the high surface-to-volume ratio of the films.
[1] C. Sanchez, C. Boissiere, D. Grosso, C. Laberty, and L. Nicole, Chem.
Mater.20, 682 (2008).
[2] C. J. Brinker, Y. F. Lu, A. Sellinger, and H. Y. Fan, Adv. Mater. 11, 579 (1999).
[3] C. Reitz, P. M. Leufke, R. Schneider, H. Hahn, and T. Brezesinski, Chem. Mater. 26, 5745 (2014).
The Promotion of the Methanol Electrooxidation Performance of Pt/CNTs By Lanthanide Oxides
Authors: Chu Haibin 
Published: February 2020

The exploration of anode catalyst materials with low platinum loading, high catalytic activity and high CO tolerant ability is one the most important issues for the development of direct methanol fuel cell (DMFC). Recently, CeO2 are found to be an efficient promoter for the Pt/C catalysts towards methanol oxidation with both higher electro-catalytic activity and better stability [1, 2]. However, the poor conductivity of CeO2 is not benefit for the fast electron transfer on the electrode catalysts, which may lead to the poor performance of the catalysts. We have synthesized doped lanthanide oxides with different compositions, sizes and exposed facets, and combine them with Pt/MWCNTs [3] via different routes. Then the oxygen storage behaviors and variable valences of lanthanide ions are optimized to improve the electro-catalytic activities and CO tolerant abilities of Pt/nanocarbon in methanol oxidation. After the investigation of the relationship between the interface structures of lanthanide oxide- Pt/MWCNTs, the mechanisms about the promotion of the catalytic performance of Pt/MWCNTs by lanthanide oxides will be discussed.
Reference:
[1] Kakati, N., Maiti, J., Lee, S. H., Jee, S. H., Viswanathan, B., Yoon, Y. S., Anode Catalysts for Direct Methanol Fuel Cells in Acidic Media: Do We Have Any Alternative for Pt or Pt-Ru?,
Chemical Reviews
2014, 114, 12397.
[2] Chu, Y. Y., Wang, Z. B., Jiang, Z. Z., Gu, D. M., Yin, G. P., A novel structural design of a Pt/C-CeO 2 catalyst with improved performance for methanol electro-oxidation by β-cyclodextrin carbonization Advanced Materials
2011, 23, 3100.
[3] Chu, H. B., Shen, Y. H., Lin, L., Qin, X. J., Feng, G., Lin, Z. Y., Wang, J. Y., Liu, H. T., Li, Y., Ionic-Liquid-Assisted Preparation of Carbon Nanotube-Supported Uniform Noble Metal Nanoparticles and Their Enhanced Catalytic Performance. Advanced Functional Materials, 2010,20, 3747-3752.