220 results on '"Kuhn, Alexander"'
Search Results
2. Bipolar electrochemiluminescence at the water/organic interface.
- Author
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Yuheng Fu, Bingbing Xie, Miaoxia Liu, Shaojuan Hou, Qunyan Zhu, Kuhn, Alexander, Lin Zhang, Wensheng Yang, and Sojic, Neso
- Published
- 2024
- Full Text
- View/download PDF
3. Annihilation Electrochemiluminescence Triggered by Bipolar Electrochemistry.
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Arias‐Aranda, Leslie R., Salinas, Gerardo, Li, Haidong, Hogan, Conor F., Kuhn, Alexander, Bouffier, Laurent, and Sojic, Neso
- Subjects
SPATIAL arrangement ,ELECTROCHEMILUMINESCENCE ,ELECTROCHEMISTRY ,ELECTRODES ,OXIDATION-reduction reaction - Abstract
Bipolar electrochemistry (BE) combined with electrochemiluminescence (ECL) has gained considerable attention as a versatile and powerful analytical technique operating in a wireless manner. However, only co‐reactant ECL has been reported so far when using a BE setup. In this work, the generation of annihilation ECL at the anodic extremity of a bipolar electrode (BPE) is demonstrated in two different spatial arrangements of the electrodes. The reported approach is based on a synergetic effect between the asymmetric electroactivity induced across the BPE, which produces different redox states of [Ru(bpy)3]2+, and the electro‐migration mechanism of the formed ionic species, allowing the localization and concentration of the ECL emission. The presented approach demonstrating annihilation ECL via BE, paves the way for the design of easy and straightforward light‐emitting platforms for multiple applications. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
- View/download PDF
4. Chemically‐Driven Autonomous Janus Electromagnets as Magnetotactic Swimmers.
- Author
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Lozon, Cara, Cornet, Antoine, Reculusa, Stephane, Garrigue, Patrick, Kuhn, Alexander, and Salinas, Gerardo
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ELECTROMAGNETS ,SWIMMERS ,MAGNETIC flux density ,FERROMAGNETIC materials ,ELECTRIC currents - Abstract
An electromagnet is a particular device that takes advantage of electrical currents to produce concentrated magnetic fields. The most well‐known example is a conventional solenoid, having the form of an elongated coil and creating a strong magnetic field through its center when it is connected to a current source. Spontaneous redox reactions located at opposite ends of an anisotropic Janus swimmer can effectively mimic a standard power source, due to their ability to wirelessly generate a local electric current. Herein, we propose the coupling of thermodynamically spontaneous redox reactions occurring at the extremities of a hybrid Mg/Pt Janus swimmer with a solenoidal geometry to generate significant magnetic fields. These chemically driven electromagnets spontaneously transform the redox‐induced electric current into a magnetic field with a strength in the range of μT upon contact with an acidic medium. Such on‐board magnetization allows them to perform compass‐like rotational motion and magnetotactic displacement in the presence of external magnetic field gradients, without the need of using ferromagnetic materials for the swimmer design. The torque force experienced by the swimmer is proportional to the internal redox current, and by varying the composition of the solution, it is possible to fine‐tune its angular velocity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. Chemically‐Driven Autonomous Janus Electromagnets as Magnetotactic Swimmers.
- Author
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Lozon, Cara, Cornet, Antoine, Reculusa, Stephane, Garrigue, Patrick, Kuhn, Alexander, and Salinas, Gerardo
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MAGNETIC flux density ,FERROMAGNETIC materials ,ELECTRIC currents ,MAGNETIC fields ,ROTATIONAL motion - Abstract
An electromagnet is a particular device that takes advantage of electrical currents to produce concentrated magnetic fields. The most well‐known example is a conventional solenoid, having the form of an elongated coil and creating a strong magnetic field through its center when it is connected to a current source. Spontaneous redox reactions located at opposite ends of an anisotropic Janus swimmer can effectively mimic a standard power source, due to their ability to wirelessly generate a local electric current. Herein, we propose the coupling of thermodynamically spontaneous redox reactions occurring at the extremities of a hybrid Mg/Pt Janus swimmer with a solenoidal geometry to generate significant magnetic fields. These chemically driven electromagnets spontaneously transform the redox‐induced electric current into a magnetic field with a strength in the range of μT upon contact with an acidic medium. Such on‐board magnetization allows them to perform compass‐like rotational motion and magnetotactic displacement in the presence of external magnetic field gradients, without the need of using ferromagnetic materials for the swimmer design. The torque force experienced by the swimmer is proportional to the internal redox current, and by varying the composition of the solution, it is possible to fine‐tune its angular velocity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. Synthesis of Multi‐Functional Graphene Monolayers via Bipolar Electrochemistry.
- Author
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Gao, Ruchao, Beladi‐Mousavi, Mohsen, Salinas, Gerardo, Zhang, Lin, and Kuhn, Alexander
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- 2024
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7. Fine‐Tuning the Optoelectronic and Redox Properties of an Electropolymerized Thiophene Derivative for Highly Selective OECT‐Based Zinc Detection.
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Nicolini, Tommaso, Shinde, Shekhar, El‐Attar, Reem, Salinas, Gerardo, Thuau, Damien, Abbas, Mamatimin, Raoux, Matthieu, Lang, Jochen, Cloutet, Eric, and Kuhn, Alexander
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ZINC ,THIOPHENES ,BIOELECTRONICS ,OXIDATION-reduction reaction ,THIN films ,POLYMERS - Abstract
Organic mixed ionic‐electronic conductors (OMIEC) have emerged as pivotal materials in organic bioelectronics, particularly when integrated into organic electrochemical transistors (OECTs). Conducting polymer‐based devices have indeed demonstrated their capability to transduce biological signals into amplified output signals, harnessing the high transconductance of OECTs. The OECT operating principle and sensing capability strongly depend on ion‐conjugated backbone coupling: the dual nature of OMIECs, i.e. ion‐conductor and electron/hole‐conductor, presents an intrinsic interface in the bulk of the thin film across which transduction of ionic signals into electronic signals and vice versa occurs. Recent works have shown how selective sodium and potassium detection can be achieved by direct chemical modification of the polymer. Such modifications introduce ligands with affinity for the cations of interest as substituents on the polymer chain. The present work explores the integration of specifically modified conducting polymers into OECT channels, offering selectivity for zinc cations. Zinc fluxes are crucial in various biological processes, and their reliable detection, especially at low concentrations, is an important challenge. By electropolymerizing a thiophene‐based trimer, modified with a dipicolylamine (DPA) substituent, a conducting polymer‐based OECT is obtained that can selectively detect Zn2+ in the 10−6 to 10−3 mol L−1 concentration range in physiological buffers. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Complex electrochemiluminescence patterns shaped by hydrodynamics at a rotating bipolar electrode.
- Author
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Arias-Aranda, Leslie R., Salinas, Gerardo, Kuhn, Alexander, Xu, Guobao, Kanoufi, Frédéric, Bouffier, Laurent, and Sojic, Neso
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- 2024
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9. Wireless Multimodal Light-Emitting Arrays Operating on the Principles of LEDs and ECL.
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Liu, Miaoxia, Arias-Aranda, Leslie R., Haidong Li, Bouffier, Laurent, Kuhn, Alexander, Sojic, Neso, and Salinas, Gerardo
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- 2024
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10. Wireless Light‐Emitting Electrode Arrays for the Evaluation of Electrocatalytic Activity.
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Boukarkour, Youness, Reculusa, Stephane, Sojic, Neso, Kuhn, Alexander, and Salinas, Gerardo
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ELECTROCATALYSTS ,OXYGEN evolution reactions ,ELECTRODES ,HYDROGEN evolution reactions ,HYDROGEN production ,LIGHT emitting diodes ,ELECTROCHEMISTRY - Abstract
Water splitting has become a sustainable and clean alternative for hydrogen production. Commonly, the efficiency of such reactions is intimately related to the physico‐chemical properties of the catalysts that constitute the electrolyzer. Thus, the development of simple and fast methods to evaluate the electrocatalytic efficiency of an electrolyzer is highly required. In this work, we present an unconventional method based on the combination of bipolar electrochemistry and light‐emitting diodes, which allows the evaluation of the electrocatalytic performance of the two types of catalysts, composing an electrolyzer, namely for oxygen and hydrogen evolution reactions, respectively. The integrated light emission of the diode acts as an optical readout of the electrocatalytic information, which simultaneously depends on the composition of the anode and the cathode. The electrocatalytic activity of Au, Pt, and Ni electrodes, connected to the LED in multiple anode/cathode configurations, towards the water splitting reactions has been evaluated. The efficiency of the electrolyzer can be represented in terms of the onset electric field (ϵonset) for light emission, obtaining variations that are in agreement with data reported with conventional electrochemistry. This work introduces a straightforward method for evaluating electrocatalysts and underscores the importance of material characterization in developing efficient electrolyzers for hydrogen production. [ABSTRACT FROM AUTHOR]
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- 2024
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11. Enantioselective recognition, synthesis, and separation of pharmaceutical compounds at chiral metallic surfaces.
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Suwankaisorn, Banyong, Aroonratsameruang, Ponart, Kuhn, Alexander, and Wattanakit, Chularat
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- 2024
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12. Additive Fertigung mit Beton – Leitfaden für die Planung und die Durchführung von Projekten.
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Mechtcherine, Viktor, Kuhn, Alexander, Mai, Inka, Nerella, Venkatesh Naidu, Weger, Daniel, Ivaniuk, Egor, and Wiens, Udo
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CONCRETE construction ,CONSTRUCTION laws ,CONSTRUCTION projects ,CONCRETE testing ,CONCRETE additives ,TEXTILE machinery - Abstract
Copyright of Beton- Und Stahlbetonbau is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2024
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13. Wireless Magnetoelectrochemical Induction of Rotational Motion.
- Author
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Tieriekhov, Kostiantyn, Sojic, Neso, Bouffier, Laurent, Salinas, Gerardo, and Kuhn, Alexander
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ROTATIONAL motion ,MAGNETIC fields ,ENERGY conversion ,ELECTRIC fields ,PHENOMENOLOGICAL theory (Physics) ,MOTION - Abstract
Electromagnetically induced rotation is a key process of many technological systems that are used in daily life, especially for energy conversion. In this context, the Lorentz force‐induced deviation of charges is a crucial physical phenomenon to generate rotation. Herein, they combine the latter with the concept of bipolar electrochemistry to design a wireless magnetoelectrochemical rotor. Such a device can be considered as a wet analog of a conventional electric motor. The main driving force that propels this actuator is the result of the synergy between the charge‐compensating ion flux along a bipolar electrode and an external magnetic field applied orthogonally to the surface of the object. The trajectory of the wirelessly polarized rotor can be controlled by the orientation of the magnetic field relative to the direction of the global electric field, producing a predictable clockwise or anticlockwise motion. Fine‐tuning of the applied electric field allows for addressing conducting objects having variable characteristic lengths. [ABSTRACT FROM AUTHOR]
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- 2024
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14. Light-emitting bipolar electrochemistry: a straightforward way to illustrate thermodynamic aspects to students.
- Author
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Salinas, Gerardo, Bouffier, Laurent, Sojic, Neso, and Kuhn, Alexander
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GIBBS' free energy ,PHYSICAL & theoretical chemistry ,ELECTROCHEMISTRY ,ELECTROMOTIVE force ,CHEMICAL reactions - Abstract
Thermodynamics is one of the most fascinating parts of physical chemistry, involved in different natural phenomena. In particular, the spontaneity or non-spontaneity of a chemical reaction is directly linked to fundamental thermodynamic parameters such as the Gibbs free energy change. Commonly this can be easily correlated with the electric work produced or required during an electrochemical reaction. In this context, the direct visualization of the electromotive force facilitates the student's understanding of the fundamental concepts behind the spontaneity of coupled reactions. Herein, we take advantage of the concepts of endogenous and exogenous bipolar electrochemistry to develop an easy and straightforward approach for the introduction of the thermodynamic concept of spontaneity to undergraduate students. In such a wireless electrochemical approach, the chemical information of two coupled reactions is encoded by the light emission of a light-emitting diode employed as bipolar electrode. This results in a direct optical readout of thermodynamic information of the involved redox reactions. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
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15. Bulk Electrosynthesis of Patchy Particles with Highly Controlled Asymmetric Features.
- Author
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Chassagne, Paul, Garrigue, Patrick, and Kuhn, Alexander
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- 2024
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16. Cable Bacteria Skeletons as Catalytically Active Electrodes.
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Digel, Leonid, Mierzwa, Maciej, Bonné, Robin, Zieger, Silvia E., Pavel, Ileana‐Alexandra, Ferapontova, Elena, Koren, Klaus, Boesen, Thomas, Harnisch, Falk, Marshall, Ian P. G., Nielsen, Lars Peter, and Kuhn, Alexander
- Abstract
Cable bacteria are multicellular, filamentous bacteria that use internal conductive fibers to transfer electrons over centimeter distances from donors within anoxic sediment layers to oxygen at the surface. We extracted the fibers and used them as free‐standing bio‐based electrodes to investigate their electrocatalytic behavior. The fibers catalyzed the reversible interconversion of oxygen and water, and an electric current was running through the fibers even when the potential difference was generated solely by a gradient of oxygen concentration. Oxygen reduction as well as oxygen evolution were confirmed by optical measurements. Within living cable bacteria, oxygen reduction by direct electrocatalysis on the fibers and not by membrane‐bound proteins readily explains exceptionally high cell‐specific oxygen consumption rates observed in the oxic zone, while electrocatalytic water oxidation may provide oxygen to cells in the anoxic zone. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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17. Kabelbakterienskelette als katalytisch aktive Elektroden.
- Author
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Digel, Leonid, Mierzwa, Maciej, Bonné, Robin, Zieger, Silvia E., Pavel, Ileana‐Alexandra, Ferapontova, Elena, Koren, Klaus, Boesen, Thomas, Harnisch, Falk, Marshall, Ian P. G., Nielsen, Lars Peter, and Kuhn, Alexander
- Abstract
Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2024
- Full Text
- View/download PDF
18. Tuning the Electrochemical Properties of Poly‐thiophenes with a 2,5‐Dithienil‐N‐subtituted‐pyrrole Bearing an Aniline Moiety for Electrochromic Devices.
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Nicolini, Tommaso, Frontana‐Uribe, Bernardo A., Kuhn, Alexander, and Salinas, Gerardo
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ELECTROCHROMIC devices ,CROSSLINKED polymers ,MOIETIES (Chemistry) ,CONDUCTING polymers ,POLYTHIOPHENES ,ANILINE ,THIOPHENES - Abstract
Conducting polymers find applications as active materials in electrochromic devices thanks to their tunable optoelectronic and electrochemical properties. Such versatility can be further enhanced by copolymerizing various aromatic monomers in order to produce new materials. In this work, we present different copolymers obtained by electropolymerization of an N‐substituted dithienylpyrrole (SNSBA) with either 3,4‐ethylendioxythiophene (EDOT) or bithiophene (BTh). The electrochemical, spectroscopic, and electrical properties were characterized across their different neutral and charged states by means of ex‐situ and in‐situ spectroelectrochemical techniques. The peculiar feature of SNSBA lies in the aniline bearing substituent of the central pyrrole unit that allows polymerization to occur at three different sites, yielding a cross‐linked polymer network. Our findings show that the SNSBA comonomer not only influences the optoelectronic properties of the final materials with respect to their homopolymers, but also induces a lowering of the hysteresis of the insulating/conducting transition (ΔEG<280 mV), likely due to the cross‐linked nature of the polymer layer. These features are promising to develop a new class of copolymers for electrochromic devices with stable, reversible, and fast operation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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19. Macroporous Polymer Cantilever Resonators for Chemical Sensing Applications.
- Author
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Dąbrowski, Marcin, Reculusa, Stéphane, Thuau, Damien, Ayela, Cédric, and Kuhn, Alexander
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MACROPOROUS polymers ,IMPRINTED polymers ,RESONATORS ,CANTILEVERS ,MICROELECTROMECHANICAL systems ,CRYSTAL resonators - Abstract
A novel, cost‐effective strategy for sensing performance enhancement of cantilever‐shaped, mass‐sensitive sensors is presented. The developed strategy relies on the introduction of macroporosity in the recognition unit. The developed sensors are successfully applied in air humidity monitoring as well as in chemical sensing. As mass‐sensitive transducers, polymer microelectromechanical systems (MEMS) in the form of poly(vinylidene fluoride‐trifluoroethylene) [P(VDF‐TrFE)] cantilever resonators are specifically developed. These resonators are modified with a hierarchically structured macroporous poly(2,3′‐bithiophene) film, acting as a sensing layer. The design of the recognition layer takes advantage of the synergistic combination of inverse opal structuring, surface imprinting, and semi‐covalent imprinting of proteins. The resulting cantilever resonators are first successfully tested for air humidity monitoring in the whole relative humidity range (ca.10 – 90%). When the recognition layer is composed of human serum albumin‐imprinted polymer (HSA‐MIP) with a hierarchical structure, it can also be used as a selective chemosensor in a concentration range from 10 pM to 20 µM. The obtained results demonstrate that the macroporosity of the receptor film significantly enhances the sensor performance. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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20. Highly Enantioselective Synthesis of Pharmaceuticals at Chiral‐Encoded Metal Surfaces.
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Somsri, Supattra, Suwankaisorn, Banyong, Yomthong, Krissanapat, Srisuwanno, Wanmai, Klinyod, Sorasak, Kuhn, Alexander, and Wattanakit, Chularat
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METALLIC surfaces ,HETEROGENEOUS catalysts ,ENANTIOSELECTIVE catalysis ,ASYMMETRIC synthesis ,PHARMACEUTICAL chemistry - Abstract
Enantioselective catalysis is of crucial importance in modern chemistry and pharmaceutical science. Although various concepts have been used for the development of enantioselective catalysts to obtain highly pure chiral compounds, most of them are based on homogeneous catalytic systems. Recently, we successfully developed nanostructured metal layers imprinted with chiral information, which were applied as electrocatalysts for the enantioselective synthesis of chiral model compounds. However, so far such materials have not been employed as heterogeneous catalysts for the enantioselective synthesis of real pharmaceutical products. In this contribution, we report the asymmetric synthesis of chiral pharmaceuticals (CPs) with chiral imprinted Pt−Ir surfaces as a simple hydrogenation catalyst. By fine‐tuning the experimental parameters, a very high enantioselectivity (up to 95 % enantiomeric excess) with good catalyst stability can be achieved. The designed materials were also successfully used as catalytically active stationary phases for the continuous asymmetric flow synthesis of pharmaceutical compounds. This illustrates the possibility of producing real chiral pharmaceuticals at such nanostructured metal surfaces for the first time. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
21. Endogenous and exogenous wireless multimodal light-emitting chemical devices.
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Liu, Miaoxia, Salinas, Gerardo, Yu, Jing, Cornet, Antoine, Li, Haidong, Kuhn, Alexander, and Sojic, Neso
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- 2023
- Full Text
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22. Bi-enzymatic chemo-mechanical feedback loop for continuous self-sustained actuation of conducting polymers.
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Arnaboldi, Serena, Salinas, Gerardo, Bichon, Sabrina, Gounel, Sebastien, Mano, Nicolas, and Kuhn, Alexander
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BILIRUBIN oxidase ,POLYMER films ,REDOX polymers ,GLUCOSE oxidase ,SOFT robotics ,OXIDATION of glucose ,CONDUCTING polymers - Abstract
Artificial actuators have been extensively studied due to their wide range of applications from soft robotics to biomedicine. Herein we introduce an autonomous bi-enzymatic system where reversible motion is triggered by the spontaneous oxidation and reduction of glucose and oxygen, respectively. This chemo-mechanical actuation is completely autonomous and does not require any external trigger to induce self-sustained motion. The device takes advantage of the asymmetric uptake and release of ions on the anisotropic surface of a conducting polymer strip, occurring during the operation of the enzymes glucose oxidase and bilirubin oxidase immobilized on its surface. Both enzymes are connected via a redox polymer at each extremity of the strip, but at the opposite faces of the polymer film. The time-asymmetric consumption of both fuels by the enzymatic reactions produces a double break of symmetry of the film, leading to autonomous actuation. An additional break of symmetry, introduced by the irreversible overoxidation of one extremity of the polymer film, leads to a crawling-type motion of the free-standing polymer film. These reactions occur in a virtually unlimited continuous loop, causing long-term autonomous actuation of the device. Owing to their interesting applications from soft robotics to biomedicine, methodologies to produce artificial actuators are desirable. Herein the authors develop an autonomous soft bioelectrochemical actuator with self-sustained motion triggered by spontaneous enzymatic reactions. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
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23. Use of comprehensive recruitment strategies in the glycemia reduction approaches in diabetes: A comparative effectiveness study (GRADE) multi-center clinical trial.
- Author
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Cherrington, Andrea L, Krause-Steinrauf, Heidi, Aroda, Vanita, Buse, John B, Fattaleh, Basma, Fortmann, Stephen P, Hall, Stephanie, Hox, Sophia H, Kuhn, Alexander, Killean, Tina, Loveland, Amy, Phillips, Lawrence S, Jackson, Analyn Uy, Waltje, Andrea, and McKee, M Diane
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DIABETES prevention ,EVALUATION of medical care ,RESEARCH ,STRATEGIC planning ,GLYCEMIC control ,HUMAN services programs ,RANDOMIZED controlled trials ,COMPARATIVE studies ,CLINICAL medicine ,RESEARCH funding ,STATISTICAL sampling ,ELECTRONIC health records ,HUMAN beings - Abstract
Background/Aims: We present and describe recruitment strategies implemented from 2013 to 2017 across 45 clinical sites in the United States, participating in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study, an unmasked, randomized controlled trial evaluating four glucose-lowering medications added to metformin in individuals with type 2 diabetes mellitus (duration of diabetes <10 years). We examined the yield of participants recruited through Electronic Health Records systems compared to traditional recruitment methods to leverage access to type 2 diabetes patients in primary care. Methods: Site selection criteria included availability of the study population, geographic representation, the ability to recruit and retain a diverse pool of participants including traditionally underrepresented groups, and prior site research experience in diabetes clinical trials. Recruitment initiatives were employed to support and monitor recruitment, such as creation of a Recruitment and Retention Committee, development of criteria for Electronic Health Record systems queries, conduct of remote site visits, development of a public screening website, and other central and local initiatives. Notably, the study supported a dedicated recruitment coordinator at each site to manage local recruitment and facilitate screening of potential participants identified by Electronic Health Record systems. Results: The study achieved the enrollment goal of 5000 participants, meeting its target with Black/African American (20%), Hispanic/Latino (18%), and age ≧60 years (42%) subgroups but not with women (36%). Recruitment required 1 year more than the 3 years originally planned. Sites included academic hospitals, integrated health systems, and Veterans Affairs Medical Centers. Participants were enrolled through Electronic Health Record queries (68%), physician referral (13%), traditional mail outreach (7%), TV, radio, flyers, and Internet (7%), and other strategies (5%). Early implementation of targeted Electronic Health Record queries yielded a greater number of eligible participants compared to other recruitment methods. Efforts over time increasingly emphasized engagement with primary care networks. Conclusion: Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness successfully recruited a diverse study population with relatively new onset of type 2 diabetes mellitus, relying to a large extent on the use of Electronic Health Record to screen potential participants. A comprehensive approach to recruitment with frequent monitoring was critical to meet the recruitment goal. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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24. Enantioselective resolution of two model amino acids using inherently chiral oligomer films with uncorrelated molecular structures.
- Author
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Nulek, Thitapond, Arnaboldi, Serena, Salinas, Gerardo, Bonetti, Giorgia, Cirilli, Roberto, Benincori, Tiziana, Wattanakit, Chularat, Flood, Adrian E., and Kuhn, Alexander
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MOLECULAR structure ,MONOMOLECULAR films ,ASPARAGINE ,KINETIC resolution ,CRYSTALLIZATION ,MOLECULES - Abstract
Preferential crystallization induced by chiral surfaces is an interesting alternative to isolate enantiopure antipodes. Herein, we take advantage of the outstanding enantiorecognition capabilities of inherently chiral oligomers to induce an enantioselective crystallization process. We exemplify this strategy with two amino acid model molecules, asparagine and glutamic acid, having a completely uncorrelated structure with respect to the template. This illustrates the versatility of the approach with potential applications in the resolution of pharmaceutical compounds. [ABSTRACT FROM AUTHOR]
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- 2023
- Full Text
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25. Electrofuels: general discussion.
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Ashraf, Talal, Avanthay, Mickaël, Batanero, Belen, Bondue, Christoph, Boucher, Dylan G., Gerulskis, Rokas, Kuhn, Alexander, Minteer, Shelley D., Mount, Andrew, Nguyen, Zachary A., Price, Robert, Rasul, Shahid, Shida, Naoki, Sokalu, Eniola, and Tan, Jeannie Z. Y.
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- 2023
- Full Text
- View/download PDF
26. Understanding and controlling organic electrosynthesis mechanism: general discussion.
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Avanthay, Mickaël, Batanero, Belen, Bondue, Christoph, Boucher, Dylan G., Broersen, Pim, Brown, Richard C. D., Chen, Luke, Choi, Anthony, Fong, Ching Wai, Fuchigami, Toshio, Hickey, David P., Kuhn, Alexander, Lam, Kevin, Liao, Yun-Ju, Liu, T. Leo, Minteer, Shelley D., Moeller, Kevin, Nguyen, Zachary A., and Shida, Naoki
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- 2023
- Full Text
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27. Interdisciplinary electrosynthesis: general discussion.
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Ackermann, Lutz, Avanthay, Mickaël, Batanero, Belen, Boucher, Dylan G., Broersen, Pim, Carroll, Emily, Flexer, Victoria, Francke, Robert, Fuchigami, Toshio, Gerulskis, Rokas, Hickey, David P., Hockin, Bee, Kuhn, Alexander, Milner, Matthew J., Minteer, Shelley D., Moeller, Kevin, Nguyen, Zachary A., Nokami, Toshiki, Rasul, Shahid, and Shida, Naoki
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- 2023
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28. Selective organic electrosynthesis: general discussion.
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Avanthay, Mickaël, Batanero, Belen, Boucher, Dylan G., Bondue, Christoph, Broersen, Pim, Brown, Richard C. D., Francke, Robert, Fuchigami, Toshio, Kuhn, Alexander, Lam, Kevin, Lin, Chia-Yu, Liu, T. Leo, Luo, Long, Minteer, Shelley D., Moeller, Kevin, Nokami, Toshiki, Price, Robert, Rasul, Shahid, and Sokalu, Eniola
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- 2023
- Full Text
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29. Magnetic field-enhanced redox chemistry on-the-fly for enantioselective synthesis.
- Author
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Salinas, Gerardo, Arnaboldi, Serena, Garrigue, Patrick, Bonetti, Giorgia, Cirilli, Roberto, Benincori, Tiziana, and Kuhn, Alexander
- Abstract
Chemistry on-the-fly is an interesting concept, extensively studied in recent years due to its potential use for recognition, quantification and conversion of chemical species in solution. In this context, chemistry on-the-fly for asymmetric synthesis is a promising field of investigation, since it can help to overcome mass transport limitations, present for example in conventional organic electrosynthesis. Herein, the synergy between a magnetic field-enhanced self-electrophoretic propulsion mechanism and enantioselective redox chemistry on-the-fly is proposed as an efficient method to boost stereoselective conversion. We employ Janus swimmers as redox-active elements, exhibiting a well-controlled clockwise or anticlockwise motion with a speed that can be increased by one order of magnitude in the presence of an external magnetic field. While moving, these bifunctional objects convert spontaneously on-the-fly a prochiral molecule into a specific enantiomer with high enantiomeric excess. The magnetic field-enhanced self-mixing of the swimmers, based on the formation of local magnetohydrodynamic vortices, leads to a significant improvement of the reaction yield and the conversion rate. [ABSTRACT FROM AUTHOR]
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- 2023
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30. Towards narrowing the reality gap in electromechanical systems: error modeling in virtual commissioning.
- Author
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Kuhn, Alexander Michael, May, Marvin Carl, Liu, Yuhui, Kuhnle, Andreas, Tekouo, William, and Lanza, Gisela
- Abstract
Digital factories and smart manufacturing systems have been increasingly researched and multiple concepts were developed to cope with prevailing ever-shortening life-cycles. The ubiquitous digital twin, despite many definitions, is often praised for accurate virtual models. One key idea to improve manufacturing through such virtual models is virtual commissioning (VC), aiming at early machine code validation. VC and its virtual models are still lacking behind their real counterparts. This gap between reality and its virtual model, commonly termed reality gap, increases the complexity of creating cyber-physical systems. An especially stark contrast is visible between the idealized virtual model and a real machine encountering errors. While error simulations exist in other fields of research, a thorough investigation in VC is missing. Thus, this paper addresses the task of narrowing the reality gap in VC based on two steps. First, a comprehensive body of research of possible errors encountered in virtual commissioning is analyzed. Secondly, the feasibility of error implementation is discussed. This paper lays the foundation for narrowing the reality gap and enabling test automation and digital twin-based control. [ABSTRACT FROM AUTHOR]
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- 2023
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31. Controlled Patterning of Complex Resistance Gradients in Conducting Polymers with Bipolar Electrochemistry.
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Salinas, Gerardo, Arnaboldi, Serena, Garrigue, Patrick, and Kuhn, Alexander
- Subjects
CONDUCTING polymers ,ELECTROCHEMISTRY ,X-ray spectroscopy ,MICROELECTRONICS ,POLYPYRROLE - Abstract
Conducting polymers have gained considerable attention for the possible design of localized electroactive patterns for microelectronics. In this work, the authors take advantage of the properties of polypyrrole, in synergy with a wireless polarization, triggered by bipolar electrochemistry, to produce localized resistance gradient patterns. The physicochemical modification is caused by the reduction and overoxidation of polypyrrole, which produces highly resistive regions at different positions along the conducting substrate at predefined locations. Due to the outstanding flexibility of polypyrrole, U‐, S‐, and E‐shaped bipolar electrodes can be formed for prove‐of‐concept experiments, and electrochemically modified in order to generate well‐defined resistance gradients. Energy‐dispersive X‐ray spectroscopy analysis of the samples confirms the localized physicochemical modifications. This approach presents as main advantages the wireless nature of bipolar electrochemistry and the possible fine‐tuning of the spatial distribution of the electrochemical modification, in comparison with more conventional patterning methods. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
32. Bottom‐Up Designed Porous Coaxial Twin‐Electrodes for Efficient Redox Cycling.
- Author
-
Šafarik, Tatjana, Karajić, Aleksandar, Reculusa, Stéphane, Bartlett, Philip N., Mano, Nicolas, and Kuhn, Alexander
- Subjects
FARADAIC current ,OXIDATION-reduction reaction ,POROUS materials ,REDUCTION potential - Abstract
Redox cycling (RC) is a powerful tool capable of amplifying faradaic currents in electroanalytical measurements, thus allowing an enhancement of sensitivity through fast multiple sequential oxidation and reduction reactions of a redox‐active analyte. Present state‐of‐the‐art RC devices are mostly based on planar electrode geometries either in 2D or 3D configurations, requiring cleanroom facilities and expensive microfabrication techniques. Here, the electrochemical elaboration and characterization of a 3D coaxial macroporous twin‐electrode is reported, obtained by following a low‐cost bottom‐up approach. A nanoengineered highly organized porous material is the basis for the design of two threaded cylindrical porous gold microelectrodes with a gap in the micrometer range that can be fine‐tuned. The potentials of the outer and inner electrodes are biased at values above and below the redox potential of the analyte so that a given molecule can participate several times in the electron exchange reaction by shuttling between both electrodes. The resulting signal amplification, combined with a straightforward synthesis strategy of the electrode architecture, allows envisioning numerous (bio)electroanalytical applications. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
33. Wireless electromechanical enantio‐responsive valves.
- Author
-
Salinas, Gerardo, Malacarne, Filippo, Bonetti, Giorgia, Cirilli, Roberto, Benincori, Tiziana, Arnaboldi, Serena, and Kuhn, Alexander
- Subjects
VALVES ,CONDUCTING polymers ,OXIDATION-reduction reaction ,CHIRAL recognition ,ELECTRIC fields ,MICROFLUIDICS - Abstract
Microfluidic valves based on chemically responsive materials have gained considerable attention in recent years. Herein, a wireless enantio‐responsive valve triggered by bipolar electrochemistry combined with chiral recognition is reported. A conducting polymer actuator functionalized with the enantiomers of an inherently chiral oligomer was used as bipolar valve to cover a tube loaded with a dye and immersed in a solution containing chiral analytes. When an electric field is applied, the designed actuator shows a reversible cantilever‐type deflection, allowing the release of the dye from the reservoir. The tube can be opened and closed by simply switching the polarity of the system. Qualitative results show the successful release of the colorant, driven by chirality and redox reactions occurring at the bipolar valve. The device works well even in the presence of chemically different chiral analytes in the same solution. These systems open up new possibilities in the field of microfluidics, including also controlled drug delivery applications. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
34. Wireless electrochemical light emission in ultrathin 2D nanoconfinements.
- Author
-
Beladi-Mousavi, S. Mohsen, Salinas, Gerardo, Bouffier, Laurent, Sojic, Neso, and Kuhn, Alexander
- Published
- 2022
- Full Text
- View/download PDF
35. Autonomous Chiral Microswimmers with Self‐mixing Capabilities for Highly Efficient Enantioselective Synthesis.
- Author
-
Arnaboldi, Serena, Salinas, Gerardo, Bonetti, Giorgia, Garrigue, Patrick, Cirilli, Roberto, Benincori, Tiziana, and Kuhn, Alexander
- Subjects
HETEROGENEOUS catalysis ,HETEROGENEOUS catalysts ,POWER resources ,ELECTROCATALYSIS ,ELECTRODES ,ENANTIOMERS ,SUSTAINABLE chemistry - Abstract
The development of chiral catalysts plays a very important role in various areas of chemical science. Heterogeneous catalysts have the general advantage of allowing a more straightforward separation from the products. One specific case of heterogeneous catalysis is electrocatalysis, being potentially a green chemistry approach. However, a typical drawback is that the redox conversion of molecules occurs only at the electrode/electrolyte interface, and not in the bulk of the electrolyte. The second limitation is that the electrodes have to be physically connected to a power supply to induce the desired reactions. To circumvent these problems, we propose here a complementary approach by replacing macroscopic electrodes with an ensemble of self‐propelled redox active microswimmers. They move autonomously in solution while transforming simultaneously a prochiral starting compound into a specific enantiomer with a very high enantiomeric excess, accompanied by a significantly increased production rate of the favorite enantiomer. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
36. Autonomous Chiral Microswimmers with Self‐mixing Capabilities for Highly Efficient Enantioselective Synthesis.
- Author
-
Arnaboldi, Serena, Salinas, Gerardo, Bonetti, Giorgia, Garrigue, Patrick, Cirilli, Roberto, Benincori, Tiziana, and Kuhn, Alexander
- Subjects
HETEROGENEOUS catalysis ,HETEROGENEOUS catalysts ,POWER resources ,ELECTROCATALYSIS ,ELECTRODES ,ENANTIOMERS ,SUSTAINABLE chemistry - Abstract
The development of chiral catalysts plays a very important role in various areas of chemical science. Heterogeneous catalysts have the general advantage of allowing a more straightforward separation from the products. One specific case of heterogeneous catalysis is electrocatalysis, being potentially a green chemistry approach. However, a typical drawback is that the redox conversion of molecules occurs only at the electrode/electrolyte interface, and not in the bulk of the electrolyte. The second limitation is that the electrodes have to be physically connected to a power supply to induce the desired reactions. To circumvent these problems, we propose here a complementary approach by replacing macroscopic electrodes with an ensemble of self‐propelled redox active microswimmers. They move autonomously in solution while transforming simultaneously a prochiral starting compound into a specific enantiomer with a very high enantiomeric excess, accompanied by a significantly increased production rate of the favorite enantiomer. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
37. Electrochemiluminescent enantioselective detection with chiral-imprinted mesoporous metal surfaces.
- Author
-
Butcha, Sopon, Yu, Jing, Pasom, Zikkawas, Goudeau, Bertrand, Wattanakit, Chularat, Sojic, Neso, and Kuhn, Alexander
- Subjects
METALLIC surfaces ,EXCITED states ,ELECTROCHEMILUMINESCENCE ,ENANTIOMERS ,PHENYLALANINE ,POROUS metals - Abstract
Chiral-imprinted mesoporous Pt–Ir alloy surfaces were combined in a synergetic way with electrochemiluminescence (ECL) to detect the two enantiomers of phenylalanine (PA) as a model compound, acting simultaneously as a chiral target and as a co-reactant to generate significant differences in ECL signals. The chiral features of the metal surfaces are converted into an enantioselective electrogeneration of the excited state of the [Ru(bpy)
3 ]2+ dye, which in fine produces the differentiating light emission with up to 20-fold differences in intensity for the two enantiomers. These findings open up the possibility of developing new ECL-based bioassays and microscopy of chiral environments. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
38. Spatially Controlled CO2 Conversion Kinetics in Natural Leaves for Motion Generation.
- Author
-
Melvin, Ambrose A., Goudeau, Bertrand, Nogala, Wojciech, and Kuhn, Alexander
- Subjects
LIGHT intensity ,CARBON dioxide ,LEAF physiology ,PHOTOSYNTHESIS ,SPERMATOZOA - Abstract
Living systems that can spontaneously exhibit directional motion belong to diverse classes such as bacteria, sperm and plankton. They have fascinated scientists in recent years to design completely artificial or biohybrid mobile objects. Natural ingredients, like parts of plants, have been used to elaborate miniaturized dynamic objects, which can move when they are combined with other, non‐natural, building blocks. Herein, we report that the precise structural tailoring of natural plant leaves allows generating a spatially predefined and confined release of oxygen gas, due to the conversion of carbon dioxide. This constitutes the driving force for generating motion, which is solely due to the respiration of leaves by photosynthesis. The rate of gas evolution can be fine‐tuned by changing the light intensity and the leaf size, allowing ultimately to control the motility of objects with dimensions ranging from the millimeter to the micrometer scale. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
39. Spatially Controlled CO2 Conversion Kinetics in Natural Leaves for Motion Generation.
- Author
-
Melvin, Ambrose A., Goudeau, Bertrand, Nogala, Wojciech, and Kuhn, Alexander
- Subjects
LIGHT intensity ,CARBON dioxide ,LEAF physiology ,PHOTOSYNTHESIS ,SPERMATOZOA - Abstract
Living systems that can spontaneously exhibit directional motion belong to diverse classes such as bacteria, sperm and plankton. They have fascinated scientists in recent years to design completely artificial or biohybrid mobile objects. Natural ingredients, like parts of plants, have been used to elaborate miniaturized dynamic objects, which can move when they are combined with other, non‐natural, building blocks. Herein, we report that the precise structural tailoring of natural plant leaves allows generating a spatially predefined and confined release of oxygen gas, due to the conversion of carbon dioxide. This constitutes the driving force for generating motion, which is solely due to the respiration of leaves by photosynthesis. The rate of gas evolution can be fine‐tuned by changing the light intensity and the leaf size, allowing ultimately to control the motility of objects with dimensions ranging from the millimeter to the micrometer scale. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
40. Site‐Selective Bipolar Electrodeposition of Gold Clusters on Graphene Oxide Microsheets at a 3D Air|Liquid Interface.
- Author
-
Kankla, Pacharapon, Luksirikul, Patraporn, Garrigue, Patrick, Goudeau, Bertrand, Bouffier, Laurent, and Kuhn, Alexander
- Subjects
GOLD clusters ,GRAPHENE oxide ,ELECTROPLATING ,GOLD ,ELECTRIC batteries ,NONIONIC surfactants ,FOAM - Abstract
An innovative wireless approach is proposed for asymmetric site‐selective deposition of gold clusters on graphene oxide microsheets by performing bipolar electrochemistry at the 3D air|liquid interface present in an assembly of bubbles constituting a foam. Exfoliated graphene oxide (EGO) microsheets are introduced into a bipolar electrochemical cell, which is filled with the foam composed of a nonionic surfactant, water, and a gold metal precursor. The EGO microparticles are located exclusively at the air|liquid interface, providing a unique 2D reaction space for bipolar electrodeposition, deployed in the 3D volume of the reactor. The application of an external electric field on such a medium enables a focalization of the polarization potential gradient and simultaneously restricts the mobility of the EGO particles, leading to their preferential in‐plane orientation with respect to the electric field lines, greatly facilitating their successful site selective modification with gold clusters. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
41. Clinical and Metabolic Characterization of Adults With Type 2 Diabetes by Age in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE) Cohort.
- Author
-
Aroda, Vanita R., Krause-Steinrauf, Heidi, Kazemi, Erin J., Buse, John B., Gulanski, Barbara I., Florez, Hermes J., Ahmann, Andrew J., Loveland, Amy, Kuhn, Alexander, Lonier, Jacqueline Y., Wexler, Deborah J., Crandall, J.P., McKee, M.D., Behringer-Massera, S., Brown-Friday, J., Xhori, E., Ballentine-Cargill, K., Duran, S., Estrella, H., and Gonzalez de la torre, S.
- Abstract
OBJECTIVE: Differences in type 2 diabetes phenotype by age are described, but it is not known whether these differences are seen in a more uniformly defined adult population at a common early stage of care. We sought to characterize age-related clinical and metabolic characteristics of adults with type 2 diabetes on metformin monotherapy, prior to treatment intensification. RESEARCH DESIGN AND METHODS: In the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness Study (GRADE), participants were enrolled who had type 2 diabetes duration <10 years, had HbA
1c 6.8–8.5%, and were on metformin monotherapy. Participants were randomly assigned to one of four additional glucose-lowering medications. We compared baseline clinical and metabolic characteristics across age categories (<45, 45 to <55, 55 to <65, and ≥65 years) using ANOVA and Pearson χ2 tests. RESULTS: Within the GRADE cohort (n = 5,047), we observed significant differences by age, with younger adults having greater racial diversity, fewer medications for common comorbidities, lower prevalence of CVD, higher weight and BMI, and more pronounced hyperglycemia and diabetic dyslipidemia and with metabolic profile indicating lower insulin sensitivity (inverse fasting insulin [1/(fasting insulin)], HOMA of steady-state insulin sensitivity, Matsuda index) and inadequate β-cell response (oral disposition index) (P < 0.05 across age categories). CONCLUSIONS: Clinical and metabolic characteristics of type 2 diabetes differ by age within the GRADE cohort. Younger adults exhibit more prominent obesity-related characteristics, including higher obesity levels and lower insulin sensitivity and β-cell compensation. Given the increasing burden of type 2 diabetes and complications, particularly among younger populations, these age-related distinctions may inform risk factor management approaches and treatment priorities. Further study will determine whether age-related differences impact response to therapy. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
42. Voice activated remote monitoring technology for heart failure patients: Study design, feasibility and observations from a pilot randomized control trial.
- Author
-
Shara, Nawar, Bjarnadottir, Margret V., Falah, Noor, Chou, Jiling, Alqutri, Hasan S., Asch, Federico M., Anderson, Kelley M., Bennett, Sonita S., Kuhn, Alexander, Montalvo, Becky, Sanchez, Osirelis, Loveland, Amy, and Mohammed, Selma F.
- Subjects
TELEMEDICINE ,HEART failure patients ,MEDICAL care use ,MEDICAL care costs ,PATIENT participation ,MEDICAL personnel ,HEART assist devices - Abstract
Background: Heart failure (HF) is a serious health condition, associated with high health care costs, and poor outcomes. Patient empowerment and self-care are a key component of successful HF management. The emergence of telehealth may enable providers to remotely monitor patients' statuses, support adherence to medical guidelines, improve patient wellbeing, and promote daily awareness of overall patients' health. Objective: To assess the feasibility of a voice activated technology for monitoring of HF patients, and its impact on HF clinical outcomes and health care utilization. Methods: We conducted a randomized clinical trial; ambulatory HF patients were randomized to voice activated technology or standard of care (SOC) for 90 days. The system developed for this study monitored patient symptoms using a daily survey and alerted healthcare providers of pre-determined reported symptoms of worsening HF. We used summary statistics and descriptive visualizations to study the alerts generated by the technology and to healthcare utilization outcomes. Results: The average age of patients was 54 years, the majority were Black and 45% were women. Almost all participants had an annual income below $50,000. Baseline characteristics were not statistically significantly different between the two arms. The technical infrastructure was successfully set up and two thirds of the invited study participants interacted with the technology. Patients reported favorable perception and high comfort level with the use of voice activated technology. The responses from the participants varied widely and higher perceived symptom burden was not associated with hospitalization on qualitative assessment of the data visualization plot. Among patients randomized to the voice activated technology arm, there was one HF emergency department (ED) visit and 2 HF hospitalizations; there were no events in the SOC arm. Conclusions: This study demonstrates the feasibility of remote symptom monitoring of HF patients using voice activated technology. The varying HF severity and the wide range of patient responses to the technology indicate that personalized technological approaches are needed to capture the full benefit of the technology. The differences in health care utilization between the two arms call for further study into the impact of remote monitoring on health care utilization and patients' wellbeing. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
43. Bifunctional Pt/Au Janus electrocatalysts for simultaneous oxidation/reduction of furfural with bipolar electrochemistry.
- Author
-
Ketkaew, Marisa, Assavapanumat, Sunpet, Klinyod, Sorasak, Kuhn, Alexander, and Wattanakit, Chularat
- Subjects
FURFURAL ,ELECTROCHEMISTRY ,ELECTROCATALYSTS ,FURFURYL alcohol ,ELECTROSYNTHESIS ,OXIDATION ,OXYGEN reduction - Abstract
The sustainable conversion of biomass-derived compounds into high added-value products is a very important contemporary scientific challenge. In this context, we report here the simultaneous electro-oxidation/-reduction of a biomass-derived compound in a one-pot approach using bipolar electrochemistry. Bifunctional Pt/Au Janus electrocatalysts are employed for a selective conversion of furfural into both, furfuryl alcohol and furoic acid, which can't be achieved when using non-Janus particles. The results emphasize the benefits of bipolar electrochemistry in the frame of electrosynthesis processes. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
44. Self-assembled monolayer protection of chiral-imprinted mesoporous platinum electrodes for highly enantioselective synthesis.
- Author
-
Butcha, Sopon, Lapeyre, Véronique, Wattanakit, Chularat, and Kuhn, Alexander
- Published
- 2022
- Full Text
- View/download PDF
45. Elektrokatalytische NADH‐Cofaktor‐Regenerierung in der Bulkphase mit bipolarer Elektrochemie.
- Author
-
Zhang, Chunhua, Zhang, Huiting, Pi, Junying, Zhang, Lin, and Kuhn, Alexander
- Subjects
DISPERSION (Chemistry) - Abstract
Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2022
- Full Text
- View/download PDF
46. Bulk Electrocatalytic NADH Cofactor Regeneration with Bipolar Electrochemistry.
- Author
-
Zhang, Chunhua, Zhang, Huiting, Pi, Junying, Zhang, Lin, and Kuhn, Alexander
- Subjects
COFACTORS (Biochemistry) ,ELECTRIC batteries ,ELECTROCHEMISTRY ,MICROELECTRODES ,BIPOLAR cells ,OXIDATION-reduction reaction - Abstract
Electrochemical regeneration of reduced nicotinamide adenine dinucleotide (NADH) is an extremely important challenge for the electroenzymatic synthesis of many valuable chemicals. Although some important progress has been made with modified electrodes concerning the reduction of NAD+, the scale‐up is difficult due to mass transport limitations inherent to large‐size electrodes. Here, we propose instead to employ a dispersion of electrocatalytically active modified microparticles in the bulk of a bipolar electrochemical cell. In this way, redox reactions occur simultaneously on all of these individual microelectrodes without the need of a direct electrical connection. The concept is validated by using [Rh(Cp*)(bpy)Cl]+ functionalized surfaces, either of carbon felt as a reference material, or carbon microbeads acting as bipolar objects. In the latter case, enzymatically active 1,4‐NADH is electroregenerated at the negatively polarized face of the particles. The efficiency of the system can be fine‐tuned by controlling the electric field in the reaction compartment and the number of dispersed microelectrodes. This wireless bioelectrocatalytic approach opens up very interesting perspectives for electroenzymatic synthesis in the bulk phase. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
47. Recent Advances in Bipolar Electrochemistry with Conducting Polymers.
- Author
-
Salinas, Gerardo, Arnaboldi, Serena, Bouffier, Laurent, and Kuhn, Alexander
- Subjects
ELECTROCHEMISTRY ,ENVIRONMENTAL remediation ,SURFACE analysis ,CONDUCTING polymers ,ELECTROSYNTHESIS ,ENERGY storage ,CONJUGATED polymers - Abstract
Conducting polymers have been extensively studied due to their potential applications ranging from sensing to energy storage, and environmental remediation. They can be easily generated by electrosynthesis and have also very interesting electrochemical features, which have been mostly examined with classic electrochemical approaches. Bipolar electrochemistry offers an attractive alternative way to synthesize and characterize the physico‐chemical properties of conducting polymers. The wireless and asymmetric features of bipolar electrochemistry can be advantageously combined with the electroactivity, tunability and easy processability of conducting polymers. This synergy has been increasingly explored in recent years for the controlled electrogeneration, surface modification and characterization of different π‐conjugated polymers. This review summarizes the advances in this context and also discusses some unconventional applications such as wireless light‐emitting devices and actuators. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
48. Hybrid light‐emitting devices for the straightforward readout of chiral information.
- Author
-
Salinas, Gerardo, Arnaboldi, Serena, Bonetti, Giorgia, Cirilli, Roberto, Benincori, Tiziana, and Kuhn, Alexander
- Subjects
CHIRAL recognition ,ANALYTICAL chemistry ,LIGHT emitting diodes ,LIGHT intensity ,OXIDATION-reduction reaction ,ENANTIOMERS - Abstract
Bipolar electrochemistry has gained increasing attention in recent years as an attractive transduction concept in analytical chemistry in general and, more specifically, in the frame of chiral recognition. Herein, we use this concept of wireless electrochemistry, based on the combination of the enantioselective oxidation of a chiral probe with the emission of light from a light‐emitting diode (LED), as an alternative for an easy and straightforward readout of the presence of chiral molecules in solution. A hybrid polymer‐microelectronic device was designed, using an inherently chiral oligomer, that is, oligo‐(3,3′‐dibenzothiophene) and a polypyrrole strip as the anode and cathode of a miniaturized LED. The wireless induced redox reactions trigger light emission when the probe with the right chirality is present in solution, whereas no light emission is observed for the opposite enantiomer. The average light intensity shows a linear correlation with the analyte concentration, and the concept opens the possibility to quantify the enantiomeric excess in mixtures of the molecular antipodes. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
49. Threshold-voltage control and enhancement-mode characteristics in multilayer tin disulfide field-effect transistors by gate-oxide passivation with an alkylphosphonic acid self-assembled monolayer.
- Author
-
Zschieschang, Ute, Holzmann, Tanja, Kuhn, Alexander, Aghamohammadi, Mahdieh, Lotsch, Bettina V., and Klauk, Hagen
- Subjects
TIN compounds synthesis ,DISULFIDES synthesis ,FIELD-effect transistors ,CHEMICAL vapor deposition ,THRESHOLD voltage - Abstract
We have synthesized crystals of two-dimensional layered tin disulfide (SnS
2 ) by chemical vapor transport and fabricated field-effect transistors based on mechanically exfoliated SnS2 multilayer platelets. We demonstrate that the threshold voltage of these transistors can be modified by passivating the gate-oxide surface with a self-assembled monolayer of an alkylphosphonic acid, affording transistors with desirable enhancement-mode characteristics. In addition to a positive threshold voltage and a large on/off current ratio, these transistors also have a steep subthreshold swing of 4 V/decade. [ABSTRACT FROM AUTHOR]- Published
- 2015
- Full Text
- View/download PDF
50. Digitaler Betonbau durch additive Verfahren – Sachstand und Forschungsbedarf.
- Author
-
Mechtcherine, Viktor, Dreßler, Inka, Empelmann, Martin, Gehlen, Christoph, Glock, Christian, Kuhn, Alexander, Lanwer, Jan Paul, Lowke, Dirk, Müller, Steffen, Neef, Tobias, Nerella, Venkatesh Naidu, Stephan, Dietmar, Vasilic, Ksenija, Weger, Daniel, and Wiens, Udo
- Subjects
CONCRETE construction ,RAPID prototyping ,MATERIALS testing ,MANUFACTURING processes ,THREE-dimensional printing - Abstract
Copyright of Beton- Und Stahlbetonbau is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
- Full Text
- View/download PDF
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