bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biomedical Applications of DNA‐Based Molecular Devices
Authors: Liu Shaoli , Jiang Qiao , Wang Yuanning , Ding Baoquan 
Published: April 2019

AbstractStrict Watson–Crick base pairing and availability by automated synthesis have allowed deoxyribonucleic acid (DNA) molecules to be used as engineerable building blocks for constructing versatile nanostructures. In recent decades, with the development of DNA nanotechnology, a range of DNA‐based dynamic molecular devices with sophisticated nanostructures have been designed and constructed. Featuring programmability and biocompatibility, the applications of DNA‐based nanodevices have been extensively focused on the interfaces of biological systems. This review summarizes the recent progress in the design of DNA devices exhibiting programmable functions for biomedical applications. In vitro and in vivo applications of DNA‐based nanodevices in cellular imaging and systemic drug delivery are highlighted. The challenges and open opportunities are also discussed.
White‐Light Generation Upon In‐Situ Amorphization of Single Crystals of [{(Me3P)3AuSn}(PhSn)3S6] and [{(Et3P)3AgSn}(PhSn)3S6]
Authors: Dornsiepen Eike , Dobener Florian , Mengel Nils , Lenchuk Olena , Dues Christof , Sanna Simone , Mollenhauer Doreen , Chatterjee Sangam , Dehnen Stefanie 
Published: April 2019

AbstractIn order to gain more information on the white‐light generation by amorphous molecular materials, the influence of metal complex substituents on the photophysical properties of potential white‐light emitters is investigated. Three compounds of the general type [{(R3P)3MSn}{PhSn}3S6)], with R/M = Me/Au (1), Et/Ag (4), and Me/Cu (5), are produced by reactions of the organotin sulfide cluster [(PhSn)4S6] (A) with the corresponding coinage metal complexes [M(PR3)3Cl]. Excess of the gold complex in the reaction leads to rearrangement and formation of [Au(PMe3)4][Au(PMe3)2][(PhSnCl)3S4] (2). The use of PMe3 instead of PEt3 in the reaction with the silver salt causes decomposition and affords [(Me3P)3AgSnCl3] (3). All compounds are structurally characterized, and the necessity of sterically stabilizing PEt3 groups at the silver complex in 4 are rationalized by density functional theory (DFT) calculations. Measurements of the photophysical properties of 1, 4, and 5 show that the introduction of the metallo‐ligands indeed affects the materials properties, and at the same time confirm that the reduction of the molecular symmetry alone is not a sufficient condition for white‐light generation (WLG), which still requires amorphicity of the compound. This is realized for 1 and 4 in situ, while reabsorption processes inhibit WLG in case of the copper compound 5.
Clean Enzymatic Oxidation of 12α‐Hydroxysteroids to 12‐Oxo‐Derivatives Catalyzed by Hydroxysteroid Dehydrogenase
Authors: Tonin Fabio , Alvarenga Natália , Ye Jia Zheng , Arends Isabel W. C. E. , Hanefeld Ulf 
Published: April 2019

AbstractThe C12 specific oxidation of hydroxysteroids is an essential reaction required for the preparation of pharmaceutical ingredients like ursodeoxycholic acid (UDCA) and chenodeoxycholic acid (CDCA), which can be synthesized by Wolff‐Kishner reduction of the obtained 12‐oxo‐hydroxysteroids. 12α‐hydroxysteroid dehydrogenases (12α‐HSDHs) have been shown to perform this reaction with high yields, under mild conditions and without the need of protection and deprotection steps, required in chemical synthesis. Here, the recombinant expression and biochemical characterization of the nicotinamide adenine dinucleotide (NAD+)‐dependent HSDH from Eggerthella lenta (El12α‐HSDH) are reported. This enzyme shows comparable properties with the well‐known nicotinamide adenine dinucleotide phosphate (NADP+)‐dependent enzyme from Clostridium sp. 48–50. In order to perform a viable and atom efficient enzymatic hydroxysteroid oxidation, NAD(P)H oxidase (NOX) was employed as cofactor regeneration system: NOX uses oxygen (O2) as sacrificial substrate and produces only water as side product. 10 mM of cholic acid was fully and selectively converted to 12‐oxo‐CDCA in 24 h. The possibility to employ this system on UCA and 7‐oxo‐deoxycholic acid (7‐oxo‐DCA) as substrates was additionally investigated. The performance of the El12α‐HSDH was evaluated also in combination with a “classical” regeneration system (oxaloacetate/malate dehydrogenase) showing full conversion in 4 h. Finally, the feasibility of a catalytic aerobic‐NAD+‐dependent enzymatic oxidation was shown on a preparative scale (oxidation of CA to 12‐oxo‐CDCA) employing the El12α‐HSDH‐NOX system in a segmented‐flow‐reactor.magnified image
A Deoximation Method for Deprotection of Ketones and Aldhydes Using a Graphene‐Oxide‐Based Co‐catalysts System
Authors: Tong Qiaolin , Liu Yang , Gao Xuezhi , Fan Zhanfang , Liu Tianfu , Li Bo , Su Dangsheng , Wang Qinghe , Cheng Maosheng 
Published: April 2019

AbstractThe deoximation of a wide range of ketoximes and aldoximes to their corresponding carbonyl compounds with high yields has been achieved using graphene oxide (GO) and sodium nitrite (NaNO2) as highly efficient catalysts and air as the green oxidant under mild conditions. The mechanism of deprotection and recycling use of catalyst were revealed in deep experiment. The carboxylic acid groups on the GO were essential for high catalytic activity.magnified image
Vulnerable Atherosclerotic Plaque Imaging by Small‐Molecule High‐Affinity Positron Emission Tomography Radiopharmaceutical
Authors: Yang Zhen , Li Feng , Yelamanchili Dedipya , Zeng Zihua , Rosales Corina , Youker Keith A. , Shen Haifa , Ferrari Mauro , Mahmarian John , Pownall Henry J. , Hamilton Dale J. , Li Zheng 
Published: April 2019

AbstractCardiovascular disease is the leading cause of death in the United States, and rupture of high‐risk or vulnerable plaques underlies most acute adverse cardiovascular events, that is, myocardial infarction and stroke. Methods to noninvasively detect and quantify the presence of vulnerable atherosclerotic plaques at the molecular/cellular level are highly desirable for timely therapeutic intervention. Currently, intraplaque neovascularization has been considered as a hallmark of unstable, vulnerable atherosclerotic plaques. Here, a high‐affinity positron emission tomography (PET) radiotracer is developed targeting vascular endothelial growth factors (VEGFR) based on a clinically used tyrosine kinase inhibitor vandetanib (ZD6474) and its potential for noninvasive detection of vulnerable plaques is tested. The in vivo PET imaging of ApoE−/− mice shows high specificity and sensitivity of the VEGFR‐PET radiotracer to vulnerable plaques. A further corroborating test of the imaging potential for clinical application is also conducted on human arterial atherosclerotic lesions. Specific VEGFR‐PET radiotracer uptake is observed by vulnerable plaques in the human arterial specimen with confirmed advanced coronary artery disease. This study suggests VEGFR as a valid biomarker for vulnerable plaque detection, and specific VEGFR‐PET is effective for noninvasive imaging of plaque vulnerability in at‐risk patients.
Short‐Channel Vertical Organic Field‐Effect Transistors with High On/Off Ratios
Authors: Dogan Tamer , Verbeek Roy , Kronemeijer Auke J. , Bobbert Peter A. , Gelinck Gerwin H. , van der Wiel Wilfred G. 
Published: April 2019

AbstractA unique vertical organic field‐effect transistor structure in which highly doped silicon nanopillars are utilized as a gate electrode is demonstrated. An additional dielectric layer, partly covering the source, suppresses bulk conduction and lowers the OFF current. Using a semiconducting polymer as active channel material, short‐channel (100 nm) transistors with ON/OFF current ratios up to 106 are realized. The electronic behavior is explained using space‐charge and contact‐limited current models and numerical simulations. The current density and switching speed of the devices are in the order of 0.1 A cm−2 and 0.1 MHz, respectively, at biases of only a few volts. These characteristics make the devices very promising for applications where large current densities, high switching speeds, and high ON/OFF ratios are required.
Designing the Charge Storage Properties of Li‐Exchanged Sodium Vanadium Fluorophosphate for Powering Implantable Biomedical Devices
Authors: Lai Chun‐Han (Matt) , Ashby David S. , Bashian Nicholas H. , Schoiber Jürgen , Liu Ta‐Chung , Lee Glenn S. , Chen San‐Yuan , Wu Pu‐Wei , Melot Brent C. , Dunn Bruce S. 
Published: April 2019

AbstractThe growing demand for bioelectronics has generated widespread interest in implantable energy storage. These implantable bioelectronic devices, powered by a complementary battery/capacitor system, have faced difficulty in miniaturization without compromising their functionality. This paper reports on the development of a promising high‐rate cathode material for implantable power sources based on Li‐exchanged Na1.5VOPO4F0.5 anchored on reduced graphene oxide (LNVOPF‐rGO). LNVOPF is unique in that it offers dual charge storage mechanisms, which enable it to exhibit mixed battery/capacitor electrochemical behavior. In this work, electrochemical Li‐ion exchange of the LNVOPF structure is characterized by operando X‐ray diffraction. Through designed nanostructuring, the charge storage kinetics of LNVOPF are improved, as reflected in the stored capacity of 107 mAh g−1 at 20C. A practical full cell device composed of LNVOPF and T‐Nb2O5, which serves as a pseudocapacitive anode, is fabricated to demonstrate not only high energy/power density storage (100 Wh kg−1 at 4000 W kg−1) but also reliable pulse capability and biocompatibility, a desirable combination for applications in biostimulating devices. This work underscores the potential of miniaturizing biomedical devices by replacing a conventional battery/capacitor couple with a single power source.
Zn0.35Co0.65O – A Stable and Highly Active Oxygen Evolution Catalyst Formed by Zinc Leaching and Tetrahedral Coordinated Cobalt in Wurtzite Structure
Authors: Wahl Sebastian , El‐Refaei Sayed M. , Buzanich Ana Guilherme , Amsalem Patrick , Lee Kug‐Seung , Koch Norbert , Doublet Marie‐Liesse , Pinna Nicola 
Published: April 2019

AbstractTo arrive to sustainable hydrogen‐based energy solutions, the understanding of water‐splitting catalysts plays the most crucial role. Herein, state‐of‐the‐art hypotheses are combined on electrocatalytic active metal sites toward the oxygen evolution reaction (OER) to develop a highly efficient catalyst based on Earth‐abundant cobalt and zinc oxides. The precursor catalyst Zn0.35Co0.65O is synthesized via a fast microwave‐assisted approach at low temperatures. Subsequently, it transforms in situ from the wurtzite structure to the layered γ‐Co(O)OH, while most of its zinc leaches out. This material shows outstanding catalytic performance and stability toward the OER in 1 m KOH (overpotential at 10 mA cm−2 ηinitial = 306 mV, η98 h = 318 mV). By comparing the electrochemical results and ex situ analyses to today's literature, clear structure‐activity correlations are able to be identified. The findings suggest that coordinately unsaturated cobalt octahedra on the surface are indeed the active centers for the OER.
Cross Talk between Transition Metal Cathode and Li Metal Anode: Unraveling Its Influence on the Deposition/Dissolution Behavior and Morphology of Lithium
Authors: Betz Johannes , Brinkmann Jan‐Paul , Nölle Roman , Lürenbaum Constantin , Kolek Martin , Stan Marian Cristian , Winter Martin , Placke Tobias 
Published: April 2019

AbstractLithium metal batteries (LMBs) combining a Li metal anode with a transition metal (TM) cathode can achieve higher practical energy densities (Wh L−1) than Li/S or Li/O2 cells. Research for improving the electrochemical behavior of the Li metal anode by, for example, modifying the liquid electrolyte is often conducted in symmetrical Li/Li or Li/Cu cells. This study now demonstrates the influence of the TM cathode on the Li metal anode, thus full cell behavior is analyzed in a way not considered so far in research with LMBs. Therefore, the deposition/dissolution behavior of Li metal and the resulting morphology is investigated with three different cathode materials (LiNi0.5Mn1.5O4, LiNi0.6Mn0.2Co0.2O2, and LiFePO4) by post mortem analysis with a scanning electron microscope. The observed large differences of the Li metal morphology are ascribed to the dissolution and crossover of TMs found deposited on Li metal and in the electrolyte by X‐ray photoelectron spectroscopy, energy‐dispersive X‐ray spectroscopy, and total reflection X‐ray fluorescence analysis. To support this correlation, the TM dissolution is simulated by adding Mn salt to the electrolyte. This study offers new insights into the cross talk between the Li metal anodes and TM cathodes, which is essential, when investigating Li metal electrodes for LMB full cells.
Penumbra detection in acute stroke with perfusion magnetic resonance imaging: Validation with 15O‐positron emission tomography
Authors: Zaro‐Weber Olivier , Fleischer Hermann , Reiblich Lucas , Schuster Alexander , Moeller‐Hartmann Walter , Heiss Wolf‐Dieter 
Published: April 2019

ObjectiveAccurate identification of the ischemic penumbra, the therapeutic target in acute clinical stroke, is of critical importance to identify patients who might benefit from reperfusion therapies beyond the established time windows. Therefore, we aimed to validate magnetic resonance imaging (MRI) mismatch–based penumbra detection against full quantitative positron emission tomography (15O‐PET), the gold standard for penumbra detection in acute ischemic stroke.MethodsTen patients (group A) with acute and subacute ischemic stroke underwent perfusion‐weighted (PW)/diffusion‐weighted MRI and consecutive full quantitative 15O‐PET within 48 hours of stroke onset. Penumbra as defined by 15O‐PET cerebral blood flow (CBF), oxygen extraction fraction, and oxygen metabolism was used to validate a wide range of established PW measures (eg, time‐to‐maximum [Tmax]) to optimize penumbral tissue detection. Validation was carried out using a voxel‐based receiver‐operating‐characteristic curve analysis. The same validation based on penumbra as defined by quantitative 15O‐PET CBF was performed for comparative reasons in 23 patients measured within 48 hours of stroke onset (group B).ResultsThe PW map Tmax (area‐under‐the‐curve = 0.88) performed best in detecting penumbral tissue up to 48 hours after stroke onset. The optimal threshold to discriminate penumbra from oligemia was Tmax >5.6 seconds with a sensitivity and specificity of >80%.InterpretationThe performance of the best PW measure Tmax to detect the upper penumbral flow threshold in ischemic stroke is excellent. Tmax >5.6 seconds–based penumbra detection is reliable to guide treatment decisions up to 48 hours after stroke onset and might help to expand reperfusion treatment beyond the current time windows. ANN NEUROL 2019;85:875–886.
A Novel Penning‐Trap Design for the High‐Precision Measurement of the 3He2 + Nuclear Magnetic Moment
Authors: Schneider Antonia , Mooser Andreas , Rischka Alexander , Blaum Klaus , Ulmer Stefan , Walz Jochen 
Published: April 2019

AbstractA new experiment is constructed aiming at the first direct high‐precision measurement of the helium‐3 nuclear magnetic moment with a relative precision of parts‐per‐billion or better. Methods similar to those used in proton and antiproton magnetic moment measurements are applied. As those techniques rely on the challenging detection of single spin‐flips, a novel Penning trap design optimized for nuclear spin‐flip detection is developed.
Effects of anthropogenic noise as a source of acoustic stress in wild populations of Hippocampus guttulatus in the Ria Formosa, south Portugal
Authors: Palma Jorge , Magalhães Marisa , Correia Miguel , Andrade José Pedro 
Published: April 2019

Abstract

This study evaluated the effects of underwater noise as a source of acoustic stress in the wild populations of Hippocampus guttulatus in the Ria Formosa, south Portugal. Two different scenarios of underwater noise were tested: transient motor boat sound (63.4–127.6 dB) and constant sound produced by the motor of the boat directly above the animals (up to 137.1 dB).
Observations were obtained in the wild between 4 and 10 m depth throughout a 3 min period, using a video camera and a hydrophone set, and compared with a control sample.
A significant increase (P < 0.05) in the respiratory rate was observed in 87% of the observed fish. Opercular movements per minute (OMPM) increased from 35.7 ± 10 (control sample) to 41.2 ± 15.5 after the first minute, to 45.5 ± 13.3 after the second (both under transient sound) and to 49.7 ± 12.5 after the third (under constant sound exposure). Differences in means between the control fish and fish observed during the second (P < 0.01) and third minute of observation (P < 0.0001) were significant. Concordantly, a significant increase (P < 0.05) in the OMPM of fish observed in the first minute and the third minute was noted. In addition to the OMPM increase, 37.5% of the animals abandoned the observation location presumably in an attempt to avoid the negative sound stimuli.
The noise caused by boat traffic generated an immediate physiological response, expressed as an increase in OMPM, and a behavioural response resulting in site abandonment, which together can be considered as a negative impact on the seahorse populations. This work contributes to an increasing number of studies that have shown that boat traffic can induce ecological and environmental consequences to aquatic species. Future research should evaluate how navigation exclusion areas could have a positive impact on the seahorse populations inhabiting shallow coastal areas.
Enterprise security economics: A self‐defense versus cyber‐insurance dilemma
Authors: Miaoui Yosra , Boudriga Noureddine 
Published: April 2019

AbstractWe propose a model that optimizes enterprise investments in cybersecurity using expected utility theory. The model allows computing (a) investment in self‐defense to reduce the risk of security breaches, (b) investment in cyber insurance to transfer the residual risk to insurance companies, and (c) investment in forensic readiness to make the insured firms capable of generating provable insurance claims about security breaches. A three‐phase–based model of vulnerability rate evolution over time is proposed and used to estimate the different planned security expenditures throughout the investment horizon. At the starting time of investment, a decision maker invests to cover the existing risk of breach and periodically spends to cover the additional risk observed due to the release of new vulnerabilities. In this work, the intermediate tranches are determined while considering three different attitudes of decision makers, namely, optimistic, pessimistic, and realistic. An analysis is conducted to assess the performance of the proposed models.
Operando Observation of Formation and Annihilation of Inhomogeneous Reaction Distribution in a Composite Electrode for Lithium‐Ion Batteries
Authors: Nakamura Takashi , Chiba Kazuki , Fakkao Mahunnop , Kimura Yuta , Nitta Kiyofumi , Terada Yasuko , Uchimoto Yoshiharu , Amezawa Koji 
Published: April 2019

AbstractInhomogeneous reaction distribution in battery electrodes can be a cause of serious capacity loss and degradation. Therefore, it is important to understand the mechanism of the reaction distribution formation. In this study, formation and annihilation of inhomogeneous charge/discharge reaction in a model LiCoO2 composite electrode were directly observed by operando two‐dimensional X‐ray absorption spectroscopy. The reaction distribution was clearly observed, and it was demonstrated that the reacted area became smaller with increasing the current density. The inhomogeneous charged situation remained even after 20 h of the open‐circuit rest and the discharge treatments. These results suggested that it is difficult to remove the inhomogeneity once it is formed in a composite electrode. High‐rate charge/discharge cycles may accumulate the inhomogeneity of the state of charge and result in significant capacity losses. The formation of the reaction distribution was strongly affected by the salt concentration in the liquid electrolyte. The expansion and annihilation rates of the charge/discharge reaction did not simply depend on the apparent ionic conductivity of the liquid electrolyte. This suggested that the salt concentration in a composite electrode varies locally by the lithiation/delithiation reactions especially under high‐rate operation. Such a local variation of the salt concentration can suppress or facilitate the charge/discharge reactions in a composite electrode.
Bifunctional Oxygen Electrocatalysts for Lithium‐Oxygen Batteries
Authors: Bae Youngjoon , Park Hyeokjun , Ko Youngmin , Kim Hyunah , Park Sung Kwan , Kang Kisuk 
Published: April 2019

AbstractThe front cover artwork is provided by the group of Prof. Kisuk Kang at the Materials Science and Engineering of Seoul National University. The image shows that the bifunctional catalyst (tunnel) lowers the polarization (congested roads) which occurs in both the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) during Li‐O2 battery operation. Read the full text of the Minireview at 10.1002/batt.201800127.
Development and validation of liquid chromatography–electrospray–tandem mass spectrometry method for determination of flibanserin in human plasma: Application to pharmacokinetic study on healthy female volunteers
Authors: Sultan Maha A. , El‐Eryan Rasha Th. , Attia Ali K. , Eissa Mona J. 
Published: April 2019

AbstractA novel rapid and highly sensitive ultra performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) bioanalytical method was established for the analysis of flibanserin in human plasma. Flibanserin d4 was used as internal standard (IS). Flibanserin and the internal standard (IS) were extracted from the plasma using protein precipitation technique with acetonitrile. A Kinetex C18 (2.6 μm, 2.1 × 50 mm) column was used for chromatographic separation and the mobile phase was a mixture of 20 mm ammonium acetate buffer (pH 4.5)–acetonitrile (50:50, v/v) with an isocratic elution mode and a flow rate of 0.3 mL/min. The analysis was performed on a Xefo TQD Waters mass spectrometer in multiple reaction monitoring mode with a positive electrospray ionization interface. The US Food and Drug Administration guidelines were followed during the bio‐analytical methods validation regarding linearity, precision, accuracy, carryover, selectivity, dilution integrity and stability. The analysis run time was carried out within 2 min over a wide linear concentration range of 5–1000 ng mL−1. Finally, the proposed method was successfully used in a pharmacokinetic study that measured flibanserin concentration in healthy, non‐pregnant female volunteers after a single 100 mg oral dose of flibanserin.