bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rational Design of Metal-Organic Frameworks/Gels As Efficient Catalysts for Oxygen Reduction Reaction
Authors: Wang Hao 
Published: February 2020

The growing pollution and energy crisis emphasize the need for the development of clean energy, such as fuel cells and metal-air batteries, in order to reduce the dependence on fossil fuels. In such clean energy devices, oxygen reduction reaction (ORR) is a key process in determining practical performance. Unfortunately it suffers from sluggish kinetics, resulting in large overpotentials and high efficiency penalties. To address this issue, rational design of non-precious metal catalysts with ORR performance comparable or even superior to precious metal is much needed.
Metal-organic frameworks (MOFs) are porous crystalline materials assembled from metal nodes and organic linkers. MOFs possess high surface areas, open metal sites, and tunable pore structures, and are therefore promising for ORR electrocatalysis, in pristine phases or as self-sacrificial templates (Fig. 1A). Besides MOFs, another class of metal-organic coordinated materials that are of great interest are metal-organic gels (MOGs). MOGs are viscoelastic solid-like materials assembled by metal-organic coordination in conjunction with other interactions. MOGs possess great inclusion properties, design flexibility and ease in synthesis, highlighting themselves as precursors for producing ORR electrocatalysts (Fig. 1A).
Herein, a series of MOFs/MOGs has been synthesized for ORR electrocatalysis. The catalytic ORR performance of the catalysts was evaluated through a rotating disk electrode technique, and the corresponding voltammograms are summarized in Fig. 1B. Several catalysts exhibit ORR activity comparable or greater than that of a commercial Pt/C benchmark, suggesting rational design approach of MOFs/MOGs offers a general solution for production of highly effective non-precious ORR electrocatalysts.

Figure 1
Hidden Features: Characterizing Carbon Electrodes in Low Ionic Strength Electrolytes for Capacitive Desalination Applications
Authors: Hawks Steven A , Fisher Adam , Knipe Jennifer M , Campbell Patrick G. , Stadermann Michael 
Published: February 2020

Capacitive desalination (CDI) is a promising technology for reducing the salinity of brackish water streams. CDI typically employs a nanoporous carbon supercapacitor architecture with the added ability to flow electrolyte through the cell for deionization. Unlike supercapacitors, though, CDI operates with low ionic-strength liquids (e.g., 20 mM NaCl). Characterization in these electrolytes unveils important features in the CV and EIS data that are not commonly observed in supercapacitor studies. Examples of such features are the emergence of a strong “charge-transfer” resistance at mid-to-high frequencies in the EIS spectrum, local minima in the CV curves that are related to a point of zero charge, and potential artifacts due to ion depletion. These features ultimately underlie the system capacitance, device resistance, and effective operational voltage window, which are all strongly related to desalination performance. Here we examine these features in flow-through electrode CDI devices (fteCDI) with activated hierarchical carbon aerogel monoliths (HCAMs) derived from carbonized and activated resorcinol-formaldehyde aerogel.
Work at LLNL was performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344.
A Versatile Redox Responsive Nanoferrogels Based Sensor for Metabolics Analytics
Authors: Mugo Samuel , Lu Weihao , Funk Nicole 
Published: February 2020

Developed is an inexpensive label free redox responsive nanoferrogel molecular receptor integrated in a chemoresisistive sensor for rapid detection of Reactive Oxygen Species (ROS) such as H2O2 and H2O2 deriving metabolites, species are of interest in myriad applications including clinical, environmental, food, and plant physiology.
Inexpensively fashioned by contact printing of redox responsive poly(N-isopropylacrylamide hydrogels herewith called ‘nanoferrogel’ on a conductive nanocellulose paper aerogel, the sensor is designed for specimen surface attachment as wearables, non-invasive transdermal sensors, and can be configured as microneedle sensor for in vivo analysis. Operating via ROS oxidation of the nanoferrogel trapped in the conductive aerogel film, the oxidized nanoferrogel volume change results in an overall change in conductivity, linearly proportional to ROS/ROS deriving metabolite concentration.
In the presentation, the responsivity of the nanoferrogel to different ROS species such as H2O2, oxylipin, antioxidants will be demonstrated. The nanoferrogel based H2O2 sensor figures of merit, featuring, rapid (≤ 1min) H2O2 response, high selectivity, low limits of detection (≤ 0.01 µM),and broad linear dynamic range of (≤ 0.03 µM to ≥ 1.5M) will be highlighted. The nanoferrogel is perfectly recyclable, by electrochemical regeneration, affording ≥ 15 multiple usable cycles.
Also showcased will be the adaptability of nanoferrogel for different sensor design configurations (e.g. micro/nanoelectrode systems), with some preliminary data attesting to the sensors utility for fundamental studies and detection of efflux of endogenous and exogenous H2O2 in single cells and other redox biomolecules, (e.g. glucose, choline).
Preliminarily the sensor can be used for detection of bacterial (model used in our study Escherichia coli) autoinducers and metabolites, of importance in bacterial communication-quorum sensing. This would be a useful platform for understanding bacterial biofilm formation. Further, the nanoferrogel sensor fashioned for utility as a wearable device for detection of redox potential and inherent sweat metabolites will be demonstrated.
Competitive Sensing Mode for Electrochemical Detection of Proteins
Authors: Gosai Agnivo , Shrotriya Pranav 
Published: February 2020

Electrochemical impedance based biosensors show promise for point-of-care and other applications due to low cost, ease of miniaturization, and label-free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in the impedance of the sensing surface, when a target molecule binds to an immobilized probe. The sensor response is proportional to the number of target molecules bound to the receptor modified surface. In complex matrices such as biological fluids, the sensor response is proportional to both the specific binding of analyte molecules to the receptors (desired signal) as well as non-specific binding of interfering molecules (noise) on the surface. Consequently, reliable detection of the analyte in complex matrices is limited by two parameters: 1) the specific binding affinity between the analyte and receptor molecules; and 2) the sensor sensitivity for analyte-receptor complexes over nonspecifically binding molecules.
We report a novel sensing approach for target detection in solution that can overcome the limitations in specificity due to a lack of sensitive discrimination between specific binding of target analyte and non-specific binding of interfering molecules. The sensing strategy involves functionalizing an array of sensing surfaces with receptor molecules with a reversible bond such that receptor molecules can be released from the surfaces on exposure to the target in solution. Thrombin and its specifically binding aptamer are used as ligand/receptor pair in the sensing experiments. Thrombin aptamers were first immobilized on the sensing surface using a reversible bond and the functionalized surface is exposed to free alpha thrombin in solution. Electrochemical impedance spectroscopy (EIS) is used to monitor the changes in aptamer surface coverage and thus determine the rate of receptor release in presence of thrombin molecules. As a negative control, functionalized surface were also exposed to gamma thrombin as it is structurally similar to alpha thrombin. Experimental results indicate that aptamer release rate is strongly dependent on specifically binding thrombin concentration while it is independent of the non-specifically binding gamma thrombin. In comparison to conventional sensing approaches, this competition sensing shows improvement in dynamic range followed by better sensitivity and specificity.
Porphyrin-Based Nanomaterials: Enhanced Electrochemiluminescence and the Application of Bioassay
Authors: Shan Dan , Zhang Guang-Yao , Cai Wen-Rong , Xin Wen-Li 
Published: February 2020

Electrochemiluminescence (ECL) has become a powerful analytical tool and has been widely applied in many fields. However, ECL still has shortcomings like poor ability to repeatedly electrochemically cycle an individual luminophore, a broad emission spectroscopy, and signal loss due to ECL reagents leaving the detection zone. Therefore, further improvement of ECL signal is still of significance. Nanomaterials can be incorporated into ECL sensor to improve efficiency, but also represent a new class of ECL emitters.
Porphyrins are 18p aromatic azaannulenes consisting of regularly arranged four methine carbons. Electrochemical and photochemical properties of porphyrins have attracted much attention for decades because of their unique aromatic structure and their beneficial characteristics such as high molar absorptivity, as well as the vital roles in biological processes such as photosynthesis, oxygen transport, and biocatalysis. Porphyrins have a flexible and adjustable molecular structure in chemical modification. The introduction of molecular-recognition motifs (e.g., hydrogen bonding, metal-ligand bonds andp-pstacking) into the porphyrin building blocks will make them form new structures, such as fibers, cubes, sheets, simple micelles and wheels. In our work, we have developed several enhanced ECL sensors based on porphyrin-nanocomposite.
For example, we synthesized zirconium-based porphyrinic metal−organic framework (MOF) for the detection of a phosphoprotein. The active center ZnTCPP in MOF-525-Zn as electron media reacts with O2 in the 3D nanocage to produce 1O2, resulting in enhanced ECL signal.

Figure 1
Bacteriophage-Assisted Magnetic Separation and Electrochemical Detection of Pathogenic Bacteria from Food Matrix
Authors: Ghuman Alyssa , Zhou Yan , Ramasamy Ramaraja P. 
Published: February 2020

Foodborne illnesses caused by pathogenic microorganisms are a major threat to worldwide public health. Listeria monocytogenes is among the most common pathogens contributing to domestically acquired foodborne illnesses (1). Most foodborne cases of listeriosis present as life-threatening illnesses in the forms of neonatal listeriosis, blood stream infection, and meningoencephalitis. There is a high priority amongst public health officials to identify Listeria outbreak sources and reduce mortality rates of this disease (2). Since the current methods for bacteria enrichment are time consuming and require sophisticated instruments, they are impossible to reproduce in a non-laboratory setting. There is a growing need to develop field-deployable technologies that are able to rapidly and accurately detect harmful pathogens in complex food matrices such as milk, juice, vegetables, meat, and poultry (3, 4).
This work describes a microfluidic cell sorting device that uses magnetophoresis to detect, separate, and concentrate tagged Listeria monocytogenes from food samples. Bacteriophage-functionalized magnetic particles will be used to isolate the bacteria in a food sample for pre-enrichment, which will allow for more rapid and selective cell sorting followed by impedimetric detection of Listeria in an electrochemical cell. We will report on the effects of flow rate and viscosity of the sample feed on the separation efficiency, as well as the throughput of enriched target bacteria from different food matrices. These enriched samples will be used in various biosensor applications for detection and identification of pathogenic bacteria in food samples.
References

E. Scallan, R. M. Hoekstra, F. J. Angulo, R. V. Tauxe, M. A. Widdowson, S. L. Roy, J. L. Jones and P. M. Griffin, Emerg Infect Dis, 17, 7 (2011).

B. Swaminathan and P. Gerner-Smidt, Microbes Infect, 9, 1236 (2007).

X. Weng and S. Neethirajan, Trends in Food Science & Technology, 65, 10 (2017).

Y. Jiang, S. Zou and X. Cao, Anal. Methods, 8, 6668 (2016).
Voltammetry of Valrubicin Quanticles
Authors: Miller Steven T , Trieu Vuong N 
Published: February 2020

Valrubicin (N-trifluoroacetyladriamycin-14-valerate) is a chemotherapy drug employed in the treatment of bladder cancer. It is currently available as Valstar®, a Cremophor-EL based formulation for intravesicular administration. At LipoMedics, we have developed a unique nanomedicinization process for water insoluble drugs using a combination of solvents and polymers we named quanticles. Here we report on the synthesis of valrubicin quanticles using phospholipid as polymer. Characterization includes particle size, drug incorporation, zeta potential and electrochemical analysis.
A series of stable phospholipid bound valrubicin quanticles were created using various combinations of PC6 (1,2-dihexanoyl-sn-glycero-3-phosphocholine), PC10 (1,2-didecanoyl-sn-glycero-3-phosphocholine), lysoPC10 (1-decanoyl-2-hydroxy-sn-glycero-3-phosphocholine) and cholesteryl oleate. Two methods of fabricating these quanticles were employed: high pressure homogenization and thin film evaporation. While characteristics like particle size and drug incorporation are similar, the methods result in formulations differing not only in their zeta potential but also in their voltammograms which indicate the formulations are either high capacitance material or low capacitance material.
As previously demonstrated with quanticles of paclitaxel, these quanticles can be distinguished by their zeta potentials and their voltammograms. Therefore, it appears to be the method of formulation that generates an ionic liquid capacitance material with distinctive high or low capacitive voltammic activity. In contrast to the previous work with paclitaxel, valrubicin adds its voltammic signature to the readings of the high capacitive material. A similar signature has not been detected in formulations of low capacitance material.
Electrochemical Detection of the Molecules of Life
Authors: Thomson Seamus David , Koehne Jessica E. 
Published: February 2020

Electrochemical sensor devices are of interest in planetary exploration missions where detection of life is a goal. All forms of life on Earth contain cellular machinery that can transform and regulate chemical energy through metabolic pathways. These processes are oxidation-reduction reactions that are performed by four key classes of molecules: flavins, nicotinamides, porphyrins, and quinones (Crawford, 2001). Electrochemical redox may prove a valuable technique for identifying and differentiating these biomolecules and become a useful tool in future life-detecting missions. In this study, we used cyclic voltammetry (CV) and differential pulse voltammetry (DPV) to measure these molecules in a 3D printed flow cell. Electrodes were fabricated from metal wires and interfaced with the flow cell through compression fittings. Glassy carbon (GC) and boron-doped diamond (BDD) electrodes were chosen as working electrodes and used to detect flavin adenine dinucleotide (FAD), riboflavin, plumbagin, anthraquinone, protoporphyrin IX and nicotinamide adenine dinucleotide (NAD). All procedures were performed in a synthetic sea water solution with a Ag/AgCl reference electrode and a platinum wire counter electrode. Limits of detection down to 10 nM were achieved by the GCE. The wide potential window of BDD proved successful in the detection all four classes of redox-active molecules in complex mixtures. Introduction of electrodes into the 3D-printed flow-cell resulted in reliable CV and DPV data, and present this electrode-integrated system as a robust device suitable for future life-detection missions.
Crawford, R. (2001). In Search of the Molecules of Life. Icarus, 154(2), 531–539. https://doi.org/10.1006/icar.2001.6714
Optical Studies of Reactively Sputtered CuGaO2 Thin Films
Authors: Saikumar Ashwin Kumar , Sundaram Kalpathy B 
Published: February 2020

Transparent conducting oxide semiconductors have been researched extensively in the past. Majority of that research has been focused primarily on the n-type transparent semiconductors. Studies on p-type transparent semiconductors have been comparatively lesser. In order to advance in the field of transparent p-n junction and other active devices, more and more researches are being done on p-type transparent semiconductors. CuGaO2 is one of the p-type transparent semiconductor that has the future prospects of being used extensively in the transparent electronics field.
For this work, CuGaO2 (50:50 of Cu2O: Ga2O3) thin films was RF sputter deposited onto both glass and quartz slides. Optical transmission studies was performed on these thin films to extract the band gap. Subsequently, optical transmission studies were performed on CuGaO2 thin films which were systematically post-sputtering annealed. The band gap extraction results of these annealed CuGaO2 thin films are reported.
Durability Test of Anode-Supported Solid Oxide Fuel Cell Under Diverse Load Conditions
Authors: Kim Youdong , Saqib Muhammad , Park Jun-Young 
Published: February 2020

Solid oxide fuel cells (SOFCs) provide an appealing electrochemical devices to convert chemical energy into electrical power with high efficiency and negligible carbon emissions. For utilizing in a wide spectrum of applications, SOFCs need to prove the operational stability over 40,000 h with less than 10% of power decay [1]. The performance deteriorations of SOFCs are induced by complex factors such as redox cycle [2], carbon deposition [3], S poisoning [4], and Cr poisoning. Therefore, understanding of fundamental degradation mechanisms under various operating conditions are important to improve the lifetime of SOFCs.
For past few decades, the durability study of SOFCs has carried out under prolonged periods of time in mainly ‘laboratory conditions’, i.e. constant current operations, well controlled fuel composition, and low level of impurities [5,6]. However, the real operating conditions normally include harsh conditions such as temperature fluctuations, current fluctuations, and fuel and air stop. Especially, the different load conditions can result in accelerating the degradation of cell components because of the local potential and temperature changing.
In this research, systematic durability investigations of anode-supported SOFCs are performed under a wide range of operating conditions including load cycle and load trip. In order to understand degradation mechanisms of the cell, various electrochemical investigations are performed such as the current-voltage polarization and electrochemical impedance spectroscopy. The morphology and microstructure of anode-supported cell are examined using field emission scanning electron microscoy and electron probe X-ray microanalyzer.

References

Y.-S. Chou, J.W. Stevenson, J.-P. Choi, J. Power Sources 250 (2014) 166–173.

T. Klemensø, C. Chung, P.H. Larsen, M.Mogensen, J. Electrochem. Soc. 152 (2005) A2186–A2192.

Mai, M. Becker, W. Assenmacher, F. Tietz, D. Hathiramani, E. Ivers-Tiffee, D. Stöver, W. Mader, Solid State Ionics 177 (2006) 1965–196

H. Yokokawa, T. Horita, K. Yamaji, H. Kishimoto, T. Yamamoto, M. Yoshikawa, Y. Mugikura, K. Tomida, Fuel Cells 13 (2013) 526–535.

Hagen, J.V.T. Høgh, R. Barfod, J. Power Sources 300 (2015) 223–228.

H. Yokokawa, ECS Trans. 35 (2011) 207–216.

T.-H. Lee, K.-Y. Park, J.-T. Kim, Y. Seo, K.B. Kim, S.-J. Song, B. Park, J.-Y. Park, J. Power Sources 276 (2015) 120–132.
Synthesis of γ’-Fe4n, a New Soft Magnetic Material for Inductors and Transformers
Authors: Stevens Tyler E , Pearce Charles Joseph , Atcitty Stan , Monson Todd 
Published: February 2020

γ’-Fe4N has many attractive properties, such as high saturation magnetization and electrical resistivity, making it an ideal candidate to replace current magnetic materials in power electronics. Doing so would allow transformers and inductors to operate in tandem with new high frequency semiconductor switches, ultimately enabling smaller devices. However, synthesis of γ’-Fe4N is challenging, especially if bulk material is desired. Furthermore, products often contain multiple phases of iron nitride or undesirable morphology and particle size. Our efforts are focused on the synthesis of nanoscale γ’-Fe4N as these materials have been shown to exhibit high permeability and therefore low loss as frequency is increased. Efforts toward the synthesis of this material, including nitridation of nanoscale iron and electrochemical nitridation of iron wire, will be presented.
Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.
(Invited) Functional Hybrids of Single-Walled Carbon Nanotubes Via π-Preserving Covalent Attachment
Authors: Reich Stephanie 
Published: February 2020

Single-walled carbon nanotubes have outstanding electronic and optical properties including ballistic transport and tunable infrared light emission. These properties arise from the delocalized π electrons of the sp
2 carbon structure and confinement effects around the nanotube circumference. There has been a long-standing need to controllably tailor single-walled nanotubes through the covalent attachment of functional groups. We recently introduced a novel way of nanotube functionalization using triazine anchors that preserves the p electrons of single-walled carbon nanotubes.[1] Infrared light emission from the optically active E
11 exciton was observed even at high degree of functionalization (4% of the carbon atoms). In this talk I will discuss functional hybrids that are built using the triazine groups to anchor functional units on single-walled carbon nanotubes. I will show how our platform provides routes toward controlled doping in carbon nanotubes and manipulating nanotube luminescence intensities via molecular switches and gold nanostructures. The presented hybrids have interesting application in ultra-high resolution bioimaging that will be discussed.
[1] Preserving π-conjugation in covalently functionalized carbon nanotubes for optoelectronic applications, A. Setaro, M. Adeli, M. Gläske, D. Przyrembel, T. Bisswanger, G. Gordeev, F. Maschietto, A. Faghani, B. Paulus, M. Weinelt, R. Arenal, R. Haag, and S. Reich, Nat. Comm.
8, 14281 (2017).