A Novel Approach to Monitor the Concentration of Phosphate Buffers in the Range of 1 M to 0.1 M Using a Silicon-Based Impedance Sensor.

We present a novel and easy approach using a silicon-based impedance chip to determine the concentration of the given aqueous buffer solution. An accurate determination of the post-dilution concentration of the buffers is necessary for ensuring optimal buffer capacity, pH stability, and to assess solution reproducibility. In this study, we focused on phosphate buffer as the test liquid to achieve precise post-dilution concentration determinations. The impedance chip consisting of a top gold ring electrode, where a test volume of 20 µL to 30 µL of phosphate buffer was introduced for impedance measurements within the frequency range of 40 Hz to 1 MHz. For impedance investigation, we used phosphate buffers with three different pH values, and the impedance was measured after diluting the phosphate buffers to a concentration of 1.00 M, 0.75 M, 0.50 M, 0.25 M, 0.10 M, 0.05 M, and 0.01 M. In order to analyze the distinctive changes in the measured impedance, an equivalent circuit was proposed and modeled. From the impedance modeling, we report that the circuit parameter RAu/Si showed exponential dependence on the concentration of phosphate buffer and no dependence on the pH values of the phosphate buffer and on the added volume inside the ring electrode. The proposed silicon-based impedance chip is quick and uses reduced liquid volume for post-dilution concentration measurements of buffers and has perspective applications in the pharmaceutical and biological domains for regulating, monitoring, and quality control of the buffers.

Periodic and Aperiodic NiFe Nanomagnet/Ferrimagnet Hybrid Structures for 2D Magnon Steering and Interferometry with High Extinction Ratio.

Magnons, quanta of spin waves, are known to enable information processing with low power consumption at the nanoscale. So far, however, experimentally realized half-adders, wave-logic, and binary output operations are based on few µm-long spin waves and restricted to one spatial direction. Here, magnons with wavelengths λ down to 50 nm in ferrimagnetic Y3 Fe5 O12 below 2D lattices of periodic and aperiodic ferromagnetic nanopillars are explored. Due to their high rotational symmetries and engineered magnetic resonances, the lattices allow short-wave magnons to propagate in arbitrarily chosen on-chip directions when excited by conventional coplanar waveguides. Performing interferometry with magnons over macroscopic distances of 350 × λ without loss of coherency, unprecedentedly high extinction ratios of up to 26 (±8) dB [31 (±2) dB] for a binary 1/0 output operation at λ = 69 nm (λ = 154 nm) are achieved in this work. The reported findings and design criteria for 2D magnon interferometry are particularly important in view of the realization of complex neuronal networks recently proposed for interfering spin waves underneath nanomagnets.

Computational Approaches for Organic Semiconductors: From Chemical and Physical Understanding to Predicting New Materials.

While a complete understanding of organic semiconductor (OSC) design principles remains elusive, computational methods─ranging from techniques based in classical and quantum mechanics to more recent data-enabled models─can complement experimental observations and provide deep physicochemical insights into OSC structure-processing-property relationships, offering new capabilities for in silico OSC discovery and design. In this Review, we trace the evolution of these computational methods and their application to OSCs, beginning with early quantum-chemical methods to investigate resonance in benzene and building to recent machine-learning (ML) techniques and their application to ever more sophisticated OSC scientific and engineering challenges. Along the way, we highlight the limitations of the methods and how sophisticated physical and mathematical frameworks have been created to overcome those limitations. We illustrate applications of these methods to a range of specific challenges in OSCs derived from π-conjugated polymers and molecules, including predicting charge-carrier transport, modeling chain conformations and bulk morphology, estimating thermomechanical properties, and describing phonons and thermal transport, to name a few. Through these examples, we demonstrate how advances in computational methods accelerate the deployment of OSCsin wide-ranging technologies, such as organic photovoltaics (OPVs), organic light-emitting diodes (OLEDs), organic thermoelectrics, organic batteries, and organic (bio)sensors. We conclude by providing an outlook for the future development of computational techniques to discover and assess the properties of high-performing OSCs with greater accuracy.

24-Month Clinical Follow-Up and Mechanistic Insights From Intravascular Imaging Following Coronary Implantation of the Novel DynamX Bioadaptor Platform.

BACKGROUND/PURPOSE: Conventional stents "cage" the coronary arteries, impairing vascular function and physiology. The DynamX Bioadaptor is a cobalt­chromium platform with uncaging elements, designed to improve arterial pulsatility, vasomotion, compliance, and positive adaptive remodelling which may attenuate late clinical events associated with the caging of arteries through conventional stents. We present the first 24-month outcomes of this device. METHODS/MATERIALS: This European multicenter study enrolled 50 patients with 50 de novo lesions treated with the DynamX Bioadaptor. Clinical follow-up is scheduled until 36 months and imaging follow-up was performed at 9-12 months. RESULTS: 24-month endpoints were target lesion failure (2 cardiac deaths), myocardial infarction (1 non-target vessel myocardial infarction), target vessel revascularisation (n = 0), and definite or probable device thrombosis (n = 0). No endpoint events occurred beyond 9 months. Paired intravascular ultrasound analysis of 18 patients from a single center revealed a 0.22 mm2 increase in device cross-sectional area at 9-12 months. Pulsatility analysis showed an increase of in-device lumen area change by 46 % compared to the caged post-procedural configuration, reducing the compliance mismatch between the treated and not-treated vessel segments (segmental compliance). Likewise, vasomotion in response to nitroglycerin improved from 0.03mm2 post-procedure to 0.17mm2 at follow-up. CONCLUSIONS: 24-month clinical data demonstrate promising safety and efficacy of the DynamX Bioadaptor. Imaging data confirmed its unique capacity to improve arterial pulsatility, vasomotion, compliance and positive adaptive remodelling after "uncaging" which might have led to the promising clinical outcomes that need to be confirmed in larger studies.

Spin dynamics, loop formation and cooperative reversal in artificial quasicrystals with tailored exchange coupling.

Aperiodicity and un-conventional rotational symmetries allow quasicrystalline structures to exhibit unusual physical and functional properties. In magnetism, artificial ferromagnetic quasicrystals exhibited knee anomalies suggesting reprogrammable magnetic properties via non-stochastic switching. However, the decisive roles of short-range exchange and long-range dipolar interactions have not yet been clarified for optimized reconfigurable functionality. We report broadband spin-wave spectroscopy and X-ray photoemission electron microscopy on different quasicrystal lattices consisting of ferromagnetic Ni81Fe19 nanobars arranged on aperiodic Penrose and Ammann tilings with different exchange and dipolar interactions. We imaged the magnetic states of partially reversed quasicrystals and analyzed their configurations in terms of the charge model, geometrical frustration and the formation of flux-closure loops. Only the exchange-coupled lattices are found to show aperiodicity-specific collective phenomena and non-stochastic switching. Both, exchange and dipolarly coupled quasicrystals show magnonic excitations with narrow linewidths in minor loop measurements. Thereby reconfigurable functionalities in spintronics and magnonics become realistic.

Data storage architectures to accelerate chemical discovery: data accessibility for individual laboratories and the community.

As buzzwords like "big data," "machine learning," and "high-throughput" expand through chemistry, chemists need to consider more than ever their data storage, data management, and data accessibility, whether in their own laboratories or with the broader community. While it is commonplace for chemists to use spreadsheets for data storage and analysis, a move towards database architectures ensures that the data can be more readily findable, accessible, interoperable, and reusable (FAIR). However, making this move has several challenges for those with limited-to-no knowledge of computer programming and databases. This Perspective presents basics of data management using databases with a focus on chemical data. We overview database fundamentals by exploring benefits of database use, introducing terminology, and establishing database design principles. We then detail the extract, transform, and load process for database construction, which includes an overview of data parsing and database architectures, spanning Standard Query Language (SQL) and No-SQL structures. We close by cataloging overarching challenges in database design. This Perspective is accompanied by an interactive demonstration available at https://github.com/D3TaLES/databases_demo. We do all of this within the context of chemical data with the aim of equipping chemists with the knowledge and skills to store, manage, and share their data while abiding by FAIR principles.

Electronic, redox, and optical property prediction of organic π-conjugated molecules through a hierarchy of machine learning approaches.

Accelerating the development of π-conjugated molecules for applications such as energy generation and storage, catalysis, sensing, pharmaceuticals, and (semi)conducting technologies requires rapid and accurate evaluation of the electronic, redox, or optical properties. While high-throughput computational screening has proven to be a tremendous aid in this regard, machine learning (ML) and other data-driven methods can further enable orders of magnitude reduction in time while at the same time providing dramatic increases in the chemical space that is explored. However, the lack of benchmark datasets containing the electronic, redox, and optical properties that characterize the diverse, known chemical space of organic π-conjugated molecules limits ML model development. Here, we present a curated dataset containing 25k molecules with density functional theory (DFT) and time-dependent DFT (TDDFT) evaluated properties that include frontier molecular orbitals, ionization energies, relaxation energies, and low-lying optical excitation energies. Using the dataset, we train a hierarchy of ML models, ranging from classical models such as ridge regression to sophisticated graph neural networks, with molecular SMILES representation as input. We observe that graph neural networks augmented with contextual information allow for significantly better predictions across a wide array of properties. Our best-performing models also provide an uncertainty quantification for the predictions. To democratize access to the data and trained models, an interactive web platform has been developed and deployed.

Direct observation of multiband transport in magnonic Penrose quasicrystals via broadband and phase-resolved spectroscopy.

Quasicrystals are aperiodically ordered structures with unconventional rotational symmetry. Their peculiar features have been explored in photonics to engineer bandgaps for light waves. Magnons (spin waves) are collective spin excitations in magnetically ordered materials enabling non-charge-based information transmission in nanoscale devices. Here, we report on a two-dimensional magnonic quasicrystal formed by aperiodically arranged nanotroughs in ferrimagnetic yttrium iron garnet. By phase-resolved spin wave imaging at gigahertz frequencies, multidirectional emission from a microwave antenna is evidenced, allowing for a quasicontinuous radial magnon distribution, not observed in reference measurements on a periodic magnonic crystal. We observe partial forbidden gaps, which are consistent with analytical calculations and indicate band formation as well as a modified magnon density of states due to backfolding at pseudo-Brillouin zone boundaries. The findings promise as-desired filters and magnonic waveguides reaching out in a multitude of directions of the aperiodic lattice.

OCELOT: An infrastructure for data-driven research to discover and design crystalline organic semiconductors.

Materials design and discovery are often hampered by the slow pace and materials and human costs associated with Edisonian trial-and-error screening approaches. Recent advances in computational power, theoretical methods, and data science techniques, however, are being manifest in a convergence of these tools to enable in silico materials discovery. Here, we present the development and deployment of computational materials data and data analytic approaches for crystalline organic semiconductors. The OCELOT (Organic Crystals in Electronic and Light-Oriented Technologies) infrastructure, consisting of a Python-based OCELOT application programming interface and OCELOT database, is designed to enable rapid materials exploration. The database contains a descriptor-based schema for high-throughput calculations that have been implemented on more than 56 000 experimental crystal structures derived from 47 000 distinct molecular structures. OCELOT is open-access and accessible via a web-user interface at https://oscar.as.uky.edu.

Detecting Bacterial Cell Viability in Few µL Solutions from Impedance Measurements on Silicon-Based Biochips.

Using two different types of impedance biochips (PS5 and BS5) with ring top electrodes, a distinct change of measured impedance has been detected after adding 1-5 µL (with dead or live Gram-positive Lysinibacillus sphaericus JG-A12 cells to 20 µL DI water inside the ring top electrode. We relate observed change of measured impedance to change of membrane potential of L. sphaericus JG-A12 cells. In contrast to impedance measurements, optical density (OD) measurements cannot be used to distinguish between dead and live cells. Dead L. sphaericus JG-A12 cells have been obtained by adding 0.02 mg/mL of the antibiotics tetracycline and 0.1 mg/mL chloramphenicol to a batch with OD0.5 and by incubation for 24 h, 30 °C, 120 rpm in the dark. For impedance measurements, we have used batches with a cell density of 25.5 × 108 cells/mL (OD8.5) and 270.0 × 108 cells/mL (OD90.0). The impedance biochip PS5 can be used to detect the more resistive and less capacitive live L. sphaericus JG-A12 cells. Also, the impedance biochip BS5 can be used to detect the less resistive and more capacitive dead L. sphaericus JG-A12 cells. An outlook on the application of the impedance biochips for high-throughput drug screening, e.g., against multi-drug-resistant Gram-positive bacteria, is given.

Increased static dielectric constant in ZnMnO and ZnCoO thin films with bound magnetic polarons.

A novel small signal equivalent circuit model is proposed in the inversion regime of metal/(ZnO, ZnMnO, and ZnCoO) semiconductor/Si3N4 insulator/p-Si semiconductor (MSIS) structures to describe the distinctive nonlinear frequency dependent capacitance (C-F) and conductance (G-F) behaviour in the frequency range from 50 Hz to 1 MHz. We modelled the fully depleted ZnO thin films to extract the static dielectric constant (εr) of ZnO, ZnMnO, and ZnCoO. The extracted enhancement of static dielectric constant in magnetic n-type conducting ZnCoO (εr ≥ 13.0) and ZnMnO (εr ≥ 25.8) in comparison to unmagnetic ZnO (εr = 8.3-9.3) is related to the electrical polarizability of donor-type bound magnetic polarons (BMP) in the several hundred GHz range (120 GHz for CdMnTe). The formation of donor-BMP is enabled in n-type conducting, magnetic ZnO by the s-d exchange interaction between the electron spin of positively charged oxygen vacancies [Formula: see text] in the BMP center and the electron spins of substitutional Mn2+ and Co2+ ions in ZnMnO and ZnCoO, respectively. The BMP radius scales with the Bohr radius which is proportional to the static dielectric constant. Here we show how BMP overlap can be realized in magnetic n-ZnO by increasing its static dielectric constant and guide researchers in the field of transparent spintronics towards ferromagnetism in magnetic, n-ZnO.

Preclinical comparative assessment of a dedicated pediatric poly-L-lactic-acid-based bioresorbable scaffold with a low-profile bare metal stent.

BACKGROUND: Polymer-based bioresorbable scaffolds (PBBS) have been assessed for coronary revascularization with mixed outcomes. Few studies have targeted pediatric-specific scaffolds. We sought to assess safety, efficacy, and short-term performance of a dedicated drug-free PBBS pediatric scaffold compared to a standard low-profile bare metal stent (BMS) in central and peripheral arteries of weaned piglets. METHODS: Forty-two devices (22 Elixir poly-L-lactic-acid-based pediatric bioresorbable scaffolds [BRS] [6 × 18 mm] and 20 control BMS Cook Formula 418 [6 × 20 mm]) were implanted in the descending aorta and pulmonary arteries (PAs) of 14 female Yucatan piglets. Quantitative measurements were collected on the day of device deployment and 30 and 90 days postimplantation to compare device patency and integrity. RESULTS: The BRS has a comparable safety profile to the BMS in the acute setting. Late lumen loss (LLL) and percent diameter stenosis (%DS) were not significantly different between BRS and BMS in the PA at 30 days. LLL and %DS were greater for BRS versus BMS in the aorta at 30 days postimplantation (LLL difference: 0.96 ± 0.26; %DS difference: 16.15 ± 4.51; p < .05). At 90 days, %DS in the aortic BRS was less, and PA BRS LLL was also less than BMS. Histomorphometric data showed greater intimal proliferation and area stenosis in the BRS at all time points and in all vessels. CONCLUSIONS: A dedicated PBBS pediatric BRS has a favorable safety profile in the acute/subacute setting and demonstrates characteristics that are consistent with adult BRSs.

Metastable Chiral Azobenzenes Stabilized in a Double Racemate.

The self-assembly of chiral organic chromophores is gaining huge significance due to the abundance of supramolecular chirality found in natural systems. We report an interdigitated molecular assembly involving axially chiral octabrominated perylenediimide (OBPDI) which transfers chiral information to achiral aromatic moieties. The crystalline two-component assemblies of OBPDI and electron-rich aromatic units were facilitated through π-hole⋅⋅⋅π donor-acceptor interactions, and the charge-transfer characteristics in the ground and excited states of the OBPDI cocrystals were established through spectroscopic and theoretical techniques. The OBPDI cocrystals entail a remarkable homochiral segregation of P and M enantiomers of both molecular entities in the same crystal system, leading to twisted double-racemic arrangements. Synergistically engendered cavities with the stored chiral information of the twisted OBPDI stabilize higher-energy P/M enantiomers of trans-azobenzene through non-covalent interactions.

Imaging the magnetic structures of artificial quasicrystal magnets using resonant coherent diffraction of circularly polarized X-rays.

Unraveling nanoscale spin structures has long been an important activity addressing various scientific interests, that are also readily adaptable to technological applications. This has invigorated the development of versatile nanoprobes suitable for imaging specimens under native conditions. Here we have demonstrated the resonant coherent diffraction of an artificial quasicrystal magnet with circularly polarized X-rays. The nanoscale magnetic structure was revealed from X-ray speckle patterns by comparing with micromagnetic simulations, as a step toward understanding the intricate relationship between the chemical and spin structures in an aperiodic quasicrystal lattice. Femtosecond X-ray pulses from free electron lasers are expected to immediately extend the current work to nanoscale structure investigations of ultrafast spin dynamics, surpassing the present spatio-temporal resolution.

Extending the scope of the carbonyl facilitated triplet excited state towards visible light excitation.

A series of extended π-conjugated benzophenone analogs was synthesized through a facile Lewis-acid catalyzed Friedel-Crafts reaction in order to exploit the integral triplet state properties of benzophenone. Extending the π-conjugated plane of the phenyl ring of benzophenone allowed tuning of the excitation wavelength from the far-UV end (∼260 nm) to the visible spectrum (∼446 nm). Compared to benzophenone, significant red-shifts in the absorption (up to 450 nm in solution) with high photostability were observed for the synthesized benzophenone analogs. As is evident from the density functional theory calculations, expansion of the ring size of the aromatic part of the benzophenone analogs induces a decrease in the HOMO-LUMO gap. The considerable extension of the electron density to the carbonyl group in the LUMO substantiates the triplet nature associated with the benzophenone analogs. By virtue of the properties of the carbonyl functionality, an apparent increase in the triplet quantum yield (ΦT = 5.4% to 87.7%) was observed for the benzophenone analogs when compared to the corresponding bare polyaromatic hydrocarbon. The spin orbit coupling was computationally estimated for the benzophenone analogs to propose pathways for the observed intersystem crossing process. The plausibility to photoexcite the aromatic-ring-fused benzophenone frameworks for triplet activation in the visible range opens the door for a new class of materials for photonic application.

γ-Herringbone Polymorph of 6,13-Bis(trimethylsilylethynyl)pentacene: A Potential Material for Enhanced Hole Mobility.

The introduction of the trialkylsilylethynyl group to the acene core is known to predominantly transform the herringbone structure of pentacene to a slip-stacked packing. However, herein, the occurrence of an unforeseen polymorph of 6,13-bis(trimethylsilylethynyl)pentacene (TMS-pentacene), with an atypical γ-herringbone packing arrangement, is reported. Intermolecular noncovalent interactions in the γ-herringbone polymorph are determined from Hirshfeld surface and quantum theory of atoms-in-molecules (QTAIM) analyses. Furthermore, a comparative truncated symmetry-adapted perturbation theory (SAPT(0)) energy decomposition analysis discloses the role of exchange repulsions that govern molecular packing in the γ-herringbone polymorph. Moreover, the computationally predicted electronic coupling and anisotropic mobility reveal the possibility of enhanced hole transport (µh =3.7 cm2 V-1 s-1 ) in the γ-herringbone polymorph, in contrast to the reported polymorph with a hole mobility of µh =0.1 cm2 V-1 s-1 .

Serial Multimodality Imaging and 2-Year Clinical Outcomes of the Novel DESolve Novolimus-Eluting Bioresorbable Coronary Scaffold System for the Treatment of Single De Novo Coronary Lesions.

OBJECTIVES: This study sought to report the late multimodality imaging and clinical outcomes of the novel poly-l-lactic-acid-based DESolve novolimus-eluting bioresorbable coronary scaffold for the treatment of de novo coronary lesions. BACKGROUND: Bioresorbable scaffolds are an alternative to drug-eluting metallic stents and provide temporary vascular scaffolding, which potentially may allow vessel restoration and reduce the risk of future adverse events. METHODS: Overall, 126 patients were enrolled at 13 international sites between November 2011 and June 2012. The primary endpoint was in-scaffold late lumen loss at 6 months. Major adverse cardiac events, the main safety endpoint, were defined as the composite of cardiac death, target vessel myocardial infarction, or clinically indicated target lesion revascularization. All patients underwent angiography at 6 months. Serial intravascular ultrasound and optical coherence tomography were performed in a subset of patients. RESULTS: The scaffold device success rate was 97% (n = 122 of 126), and procedural success was 100% (n = 122 of 122). The major adverse cardiac event rate was 3.3% (n = 4 of 122) at 6 months and 7.4% (n = 9 of 122) at 24 months, including 1 probable stent thrombosis within the first month. At 6-month angiographic follow-up, in-scaffold late lumen loss was 0.20 ± 0.32 mm. Paired intravascular ultrasound analysis demonstrated a significant increase in vessel, lumen and scaffold dimensions between post-procedure and 6-month follow-up, and strut-level optical coherence tomography analysis showed full strut coverage in 99 ± 1.7%. CONCLUSIONS: Our results showed favorable performance of the DESolve scaffold, effective inhibition of neointimal hyperplasia, and for the first time, early luminal and scaffold growth at 6 months with sustained efficacy and safety through 2 years. (Elixir Medical Clinical Evaluation of the DESolve Novolimus Eluting Bioresorbable Coronary Scaffold System-The DESolve Nx Trial; NCT02086045).

Serial multimodality imaging and 2-Year clinical outcomes of the novel DESolve novolimus-eluting bioresorbable coronary scaffold system for the treatment of single de novo coronary lesions

OBJECTIVES:This study sought to report the late multimodality imaging and clinical outcomes of the novel poly-l-lactic-acid-based DESolve novolimus-eluting bioresorbable coronary scaffold for the treatment of de novo coronary lesions. BACKGROUND: Bioresorbable scaffolds are an alternative to drug-eluting metallic stents and provide temporary vascular scaffolding, which potentially may allow vessel restoration and reduce the risk of future adverse events...

A next-generation bioresorbable coronary scaffold system: from bench to first clinical evaluation: 6- and 12-month clinical and multimodality imaging results.

OBJECTIVES: This study sought to perform clinical and imaging assessments of the DESolve Bioresorbable Coronary Scaffold (BCS). BACKGROUND: BCS, which is drug eluting, may have potential advantages compared with conventional metallic drug-eluting stents. The DESolve system, designed to provide vessel support and neointimal suppression, combines a poly-l-lactic acid-based scaffold with the antiproliferative myolimus. METHODS: The DESolve First-in-Man (a non-randomized, consecutive enrollment evaluation of the DESolve myolimus eluting bioresorbable coronary stent in the treatment of patients with de novo native coronary artery lesions) trial was a prospective multicenter study enrolling 16 patients eligible for treatment. The principal safety endpoint was a composite of cardiac death, myocardial infarction, and clinically indicated target lesion revascularization. The principal imaging endpoint was in-scaffold late lumen loss (LLL) assessed by quantitative coronary angiography (QCA) at 6 months. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) imaging was performed at baseline and 6 months; multislice computed tomography (MSCT) was performed at 12 months. RESULTS: Acute procedural success was achieved in 15 of 15 patients receiving a study scaffold. At 12 months, there was no scaffold thrombosis and no major adverse cardiac events directly attributable to the scaffold. At 6 months, in-scaffold LLL (by QCA) was 0.19 ± 0.19 mm; neointimal volume (by IVUS) was 7.19 ± 3.56%, with no evidence of scaffold recoil or late malapposition. Findings were confirmed with OCT and showed uniform, thin neointimal coverage (0.12 ± 0.04 mm). At 12 months, MSCT demonstrated excellent vessel patency. CONCLUSIONS: This study demonstrated the feasibility and efficacy of the DESolve BCS. Results showing low in-scaffold LLL, low % neointimal volume at 6 months, no chronic recoil, and maintenance of lumen patency at 12 months prompt further study. (DESolve First-in-Man; EudraCT number 2011-000027-32).