This paper investigates optimal sensor placement strategies for angle-of-arrival (AOA) localization in three-dimensional space. We adopt the A-optimality criterion to determine optimal sensor ...placements under the Gaussian measurement noise. A comprehensive analysis of optimal sensor-target geometries is provided with no restriction on the number of AOA sensors, sensor-target range, and noise variances. A resistor network analogy is also presented to enable quick determination of optimal sensor-target geometries. The analytical results are verified by extensive simulation studies.
Metal-organic frameworks (MOFs) are porous crystalline materials constructed from metal ions or clusters and multidentate organic ligands. Recently, the use of MOFs or MOF composites as catalysts for ...synergistic catalysis and tandem reactions has attracted increasing attention due to their tunable open metal centres, functional organic linkers, and active guest species in their pores. In this review, the applications of MOFs with multiple active sites in synergistic organic catalysis, photocatalysis and tandem reactions are discussed. These multifunctional MOFs can be categorized by the type of active centre as follows: (i) open metal centres and functional organic linkers in the MOF structure, (ii) active guest sites in the pores and active sites in the MOF structure, and (iii) bimetallic nanoparticles (NPs) on MOF supports. The types of synergistic catalysis and tandem reactions promoted by multifunctional MOFs and their proposed mechanisms are presented in detail. Here, catalytic MOFs with a single type of active site and MOFs that only serve as supports to enhance substrate adsorption are not discussed.
Various active sites incorporated into metal-organic frameworks (MOFs) are suitable for synergistic catalysis and tandem reactions.
Soft electronics are intensively studied as the integration of electronics with dynamic nonplanar surfaces has become necessary. Here, a discussion of the strategies in materials innovation and ...structural design to build soft electronic devices and systems is provided. For each strategy, the presentation focuses on the fundamental materials science and mechanics, and example device applications are highlighted where possible. Finally, perspectives on the key challenges and future directions of this field are presented.
Soft electronics are intensively studied as the integration of electronics with dynamic nonplanar surfaces has become necessary. The advances that have been made so far in materials innovation and structural design for soft electronics are summarized and some key challenges and future directions of this field are discussed.
Variational quantum eigensolver (VQE) with a unitary coupled cluster (UCC) ansatz has been suggested as a promising method for electronic structure calculations on future quantum computers. However, ...the complexity of the excitation terms for UCC with the single and double excitations (UCCSD) ansatz is up‐bounded to OM−N2N2, where N is the number of electrons and M is the number of spin orbitals. The gate complexity of quantum circuit for the UCCSD ansatz is up‐bounded to OMM−N2N2 using the Jordan–Wigner transformation. These complexities significantly limit the implementation of UCCSD on current Noisy Intermediate‐Scale Quantum (NISQ) devices. Herein, we developed a k‐QUpCCGSD ansatz which is based on the generalized paired double excitation operators and the particle preserving exchange gate. The former reduces the number of the excitation operators, the latter reduces the number of qubit gates for transforming excitation operators to quantum circuit. The gate complexity of the proposed k‐QUpCCGSD ansatz is up‐bounded to O(kM2), which significantly reduce the complexity of the VQE algorithm on NISQ devices. The performance of the proposed ansatz on VQE is demonstrated by calculating ground‐state dissociation energy curves of the H6, LiH, H2O, and BeH2 molecules with the STO‐3G minimal basis set, and the accuracy is evaluated by comparing to the full configuration interaction (FCI) benchmarks. Moreover, we compare the number of quantum gates, especially the CNOT gates, and accuracies of various ansatzes. The assessments have shown that the accuracy of qubit unitary coupled cluster (QUCC) ansatzes is slightly worse than that of the UCC ones, but the circuit complexity of QUCC is much less than that of UCC. Among the tested QUCC ansatzes, k‐QUpCCGSD achieves higher accuracy with fewer quantum gates than QUCCSD, and k‐QUpCCGSD is a promising ansatz for VQE calculation on NISQ devices.
A new k‐QUpCCGSD ansatz is proposed for the VQE algorithm, which is based on the generalized paired double excitation operators and the particle preserving exchange gate. Theoretical analysis demonstrates that the k‐QUpCCGSD ansatz has a gate complexity of OkM2, much less than the UCCSD ansatz. Numerical calculations show that k‐QUpCCGSD achieves considerable accuracy with fewer quantum gates than the UCCSD ansatz. k‐QUpCCGSD is a promising method for the electronic structure calculation on NISQ devices.
Transition‐metal phosphides have stimulated great interest as catalysts to drive the hydrogen evolution reaction (HER), but their use as bifunctional catalytic electrodes that enable efficient ...neutral‐pH water splitting has rarely been achieved. Herein, we report the synthesis of ternary Ni0.1Co0.9P porous nanosheets onto conductive carbon fiber paper that can efficiently and robustly catalyze both the HER and water oxidation in 1 m phosphate buffer (PBS; pH 7) electrolyte under ambient conditions. A water electrolysis cell comprising the Ni0.1Co0.9P electrodes demonstrates remarkable activity and stability for the electrochemical splitting of neutral‐pH water. We attribute this performance to the new ternary Ni0.1Co0.9P structure with porous surfaces and favorable electronic states resulting from the synergistic interplay between nickel and cobalt. Ternary metal phosphides hold promise as efficient and low‐cost catalysts for neutral‐pH water splitting devices.
Sheets and paper: Ternary Ni0.1Co0.9P porous nanosheets anchored onto conductive carbon fiber paper, can be used as a bifunctional catalytic material for driving both water reduction and oxidation reactions efficiently in neutral‐pH electrolyte under ambient conditions.
Abstract
Background
The emergence of coronavirus disease 2019 (COVID-19) is a major healthcare threat. The current method of detection involves a quantitative polymerase chain reaction (qPCR)–based ...technique, which identifies the viral nucleic acids when present in sufficient quantity. False-negative results can be achieved and failure to quarantine the infected patient would be a major setback in containing the viral transmission. We aim to describe the time kinetics of various antibodies produced against the 2019 novel coronavirus (SARS-CoV-2) and evaluate the potential of antibody testing to diagnose COVID-19.
Methods
The host humoral response against SARS-CoV-2, including IgA, IgM, and IgG response, was examined by using an ELISA-based assay on the recombinant viral nucleocapsid protein. 208 plasma samples were collected from 82 confirmed and 58 probable cases (qPCR negative but with typical manifestation). The diagnostic value of IgM was evaluated in this cohort.
Results
The median duration of IgM and IgA antibody detection was 5 (IQR, 3–6) days, while IgG was detected 14 (IQR, 10–18) days after symptom onset, with a positive rate of 85.4%, 92.7%, and 77.9%, respectively. In confirmed and probable cases, the positive rates of IgM antibodies were 75.6% and 93.1%, respectively. The detection efficiency by IgM ELISA is higher than that of qPCR after 5.5 days of symptom onset. The positive detection rate is significantly increased (98.6%) when combining IgM ELISA assay with PCR for each patient compared with a single qPCR test (51.9%).
Conclusions
The humoral response to SARS-CoV-2 can aid in the diagnosis of COVID-19, including subclinical cases.
The time kinetics of humoral responses against the novel coronavirus (SARS-CoV-2) are characterized in patients with COVID-19 by nucleocapsid-based enzyme-linked immunosorbent assay. The antibody testing can aid in the diagnosis of COVID-19 when combined with quantitative polymerase chain reaction, including in subclinical cases.
One-dimensional （1D） ZnO nanostructures have been studied intensively and extensively over the last decade not only for their remarkable chemical and physical properties, but also for their diverse ...current and future technological applications. This article gives a comprehensive overview of the progress that has been made within the context of 1D ZnO nanostructures synthesized via wet chemical methods. We will cover the synthetic methodologies and the corresponding growth mechanisms, various nanostructures grown, their doping and alloying, and position-controlled growth on substrates. Finally, we will review their functional properties in catalysis, hydrophobic surface modification, sensing, and electronic, optical, optoelectronic, and energy harvesting devices.
The anode oxygen evolution reaction (OER) is known to largely limit the efficiency of electrolyzers owing to its sluggish kinetics. While crystalline metal oxides are promising as OER catalysts, ...their amorphous phases also show high activities. Efforts to produce amorphous metal oxides have progressed slowly, and how an amorphous structure benefits the catalytic performances remains elusive. Now the first scalable synthesis of amorphous NiFeMo oxide (up to 515 g in one batch) is presented with homogeneous elemental distribution via a facile supersaturated co‐precipitation method. In contrast to its crystalline counterpart, amorphous NiFeMo oxide undergoes a faster surface self‐reconstruction process during OER, forming a metal oxy(hydroxide) active layer with rich oxygen vacancies, leading to superior OER activity (280 mV overpotential at 10 mA cm−2 in 0.1 m KOH). This opens up the potential of fast, facile, and scale‐up production of amorphous metal oxides for high‐performance OER catalysts.
Amorphous NiFeMo oxide (up to 515 g one batch) with homogeneous elemental distribution was synthesized through a facile supersaturated co‐precipitation method. The amorphous NiFeMo oxide undergoes rapid surface self‐reconstruction during OER that forms a metal oxy(hydroxide) active layer with oxygen vacancies, enabling efficient OER catalysis.
Summary
Purple carrots, the original domesticated carrots, accumulate highly glycosylated and acylated anthocyanins in root and/or petiole. Previously, a quantitative trait locus (QTL) for ...root‐specific anthocyanin pigmentation was genetically mapped to chromosome 3 of carrot. In this study, an R2R3‐MYB gene, namely DcMYB113, was identified within this QTL region. DcMYB113 expressed in the root of ‘Purple haze’, a carrot cultivar with purple root and nonpurple petiole, but not in the roots of two carrot cultivars with a purple root and petiole (Deep purple and Cosmic purple) and orange carrot ‘Kurodagosun’, which appeared to be caused by variation in the promoter region. The function of DcMYB113 from ‘Purple haze’ was verified by transformation in ‘Cosmic purple’ and ‘Kurodagosun’, resulting in anthocyanin biosynthesis. Transgenic ‘Kurodagosun’ carrying DcMYB113 driven by the CaMV 35S promoter had a purple root and petiole, while transgenic ‘Kurodagosun’ expressing DcMYB113 driven by its own promoter had a purple root and nonpurple petiole, suggesting that root‐specific expression of DcMYB113 was determined by its promoter. DcMYB113 could activate the expression of DcbHLH3 and structural genes related to anthocyanin biosynthesis. DcUCGXT1 and DcSAT1, which were confirmed to be responsible for anthocyanins glycosylation and acylation, respectively, were also activated by DcMYB113. The WGCNA identified several genes co‐expressed with anthocyanin biosynthesis and the results indicated that DcMYB113 may regulate anthocyanin transport. Our findings provide insight into the molecular mechanism underlying root‐specific anthocyanin biosynthesis and further modification in carrot and even other root crops.
SnSe is challenging to use in thermoelectric devices due to difficulties in simultaneously optimizing its thermoelectric and mechanical properties. Here, the authors show a unique solvothermal ...synthetic environmental design to fabricate super‐large and micro/nanoporous Sn0.965Se microplates by using CrCl3. Cl− ions to trigger Sn‐vacancy formation and optimize the hole concentration to ≈3 × 1019 cm−3, while the as‐formed Cr(OH)3 colloidal precipitations act as “templates” to achieve micro/nanoporous features, leading to low lattice thermal conductivity of ≈0.2 W m−1 K−1 in the as‐sintered polycrystal, contributing to a high ZT of ≈2.4 at 823 K and an average ZT of ≈1.1. Of particular note, the polycrystal exhibits high hardness (≈2.26 GPa) and compression strength (≈109 MPa), strengthened by grain refinement and vacancy‐induced lattice distortions and dislocations; while a single‐leg device provides a stable output power (>100 mW) and conversion efficiency of ≈10% by a temperature difference of 425 K, indicating great potential for applying to practical thermoelectric devices.
A solvothermal synthetic environmental design to fabricate super‐large and micro/nanoporous Sn0.965Se microplates using CrCl3 is employed, and the mechanically robust polycrystals sintered from these microplates exhibit a high ZT of ≈2.4 at 823 K and an average ZT of ≈1.1, leading to a conversion efficiency of ≈10% by a temperature difference of 425 K in the single‐leg device.
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