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Simple urea-based chemicals have been used in the textile industry for "ironing-free clothes" for decades. One of the most used chemicals is 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU), which consists of urea, glyoxal and formaldehyde. DMDHEU and related chemicals are considered safe and environmentally benign. We have therefore synthesized these compounds and studied their properties as H 2 S scavengers as alternatives to the "triazine" compounds used in the offshore industry today. Several derivatives are easily available, and we have evaluated their scavenging properties using Raman spectroscopy. This study reveals that this class of compounds scavenges H 2 S under conditions similar to the triazine-based scavengers and gives insight into the structural requirements needed.

In this study, the mechanism of self-promoted N-glycosylations is extensively investigated through kinetic experiments, computational studies, and nucleophilic competition experiments. Based on the findings, the mechanism is proposed to be initiated by proton transfer from the acidic sulfonyl carbamate to the trichloroacetimidate, upon formation of an associated contact ion pair. This ion pair then collapses in an S N 1-like fashion, with formation of an oxocarbeniumion-like intermediate. According to the proposed mechanism, stereospecificity arises from the associated nature of all intermediates formed throughout the reaction. During the mechanistic study, it was also found that the sulfonyl carbamates have catalytic properties if a competing nucleophile is present., (© 2024 Wiley-VCH GmbH.)

One of the most promising approaches towards large-scale quantum computation uses devices based on many Josephson junctions. Yet, even today, open questions regarding the single junction remain unsolved, such as the detailed understanding of the quantum phase transitions, the coupling of the Josephson junction to the environment or how to improve the coherence of a superconducting qubit. Here we design and build an engineered on-chip reservoir connected to a Josephson junction that acts as an efficient bolometer for detecting the Josephson radiation under non-equilibrium, that is, biased conditions. The bolometer converts the a.c. Josephson current at microwave frequencies up to about 100 GHz into a temperature rise measured by d.c. thermometry. A circuit model based on realistic parameter values captures both the current-voltage characteristics and the measured power quantitatively. The present experiment demonstrates an efficient, wide-band, thermal detection scheme of microwave photons and provides a sensitive detector of Josephson dynamics beyond the standard conductance measurements., Competing Interests: Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

We report measurements of the current-phase relation of two voltage-controlled semiconductor-superconductor hybrid Josephson junctions (JJs) in series. The two hybrid junctions behave similar to a single-mode JJ with effective transparency determined by the ratio of Josephson coupling strengths of the two junctions. Gate-voltage control of Josephson coupling (measured from switching currents) allows tuning of the harmonic content from sinusoidal, for asymmetric tuning, to highly nonsinusoidal, for symmetric tuning. The experimentally observed tunable harmonic content agrees with a model based on two conventional (sinusoidal) JJs in series.

Gluconolactone serves as a readily available and inexpensive starting material for synthesizing the potential platform chemical (Z)-3-deoxy-1,2 : 5,6-di-O-isopropylidene-D-erythro-hex-3-enolactone in two steps. In this work, the selective elimination of triacetone gluconolactone was optimized. The resulting product is a versatile molecule, capable of being transformed into various compound classes in one or a few steps, i. e. potentially a new biomass-based platform chemical. This study demonstrates how it can be transformed into furanics, rare sugars, β-ketoamides, and amino furanones., (© 2024 The Author(s). Chemistry - A European Journal published by Wiley-VCH GmbH.)

In this communication, a practical method for using cheap and easily available silylene chlorides for diol protection is presented. The method is based on activation of the reagents using Finkelstein-like conditions. Silylene acetals of carbohydrates are synthesized, and it is furthermore shown how these can be regioselectively opened using Grignard reagents.

In this work, we present the synthesis of a series of L-thiorhamnosyl donors containing O -carbamate protective groups and the study of their influence on the selectivity in rhamnosylations. It is found that a carbamate on the C-4 position increased the β selectivity compared with carbamates on the C2 or C3 positions, respectively, and when no carbamate group was installed. In addition it is found that the observed β selectivity was greater when the 4- O carbamate had less electron withdrawing groups on the nitrogen. The influence of using triflic acid catalysis was studied as well and it was found to lower the β-selectivity. In addition a new efficient one step synthesis of selectively 2,4- O -benzylated rhamnosides was established using phase transfer catalysis.

Objective(s): This randomized controlled study evaluated the effectiveness of a Telehealth Aural Rehabilitation (TeleAR) training protocol to improve outcomes for adult cochlear implant (CI) users., Methods: This was a multisite clinical study with participants randomized to either an AR treatment or active control group. The AR protocol consisted of auditory training (words, sentences, and speech tracking), informational counseling, and communication strategies. The control group participants engaged in cognitive stimulation activities (crosswords, sudoku, etc.). Each group completed 6 weekly 90-min individual treatment sessions delivered remotely. Twenty postlingually deafened adult CI users participated. Assessments were completed pretreatment and 1 week and 2 months posttreatment., Results: Repeated-measures ANOVA and planned contrasts were used to compare group performance on AzBio Sentences, Hearing Handicap Inventory (HHI), Client Oriented Scale of Improvement (COSI), and Glasgow Benefit Inventory (GBI). The two groups were statistically equivalent on all outcome measures at pre-assessment. There was a statistically significant main effect of time for all measures. Improvement over time was observed for participants in both groups, with greater improvement seen for the AR than the CT group on all outcome measures. The AR group showed medium to large effect sizes on all measures over time, suggesting clinically significant outcomes., Conclusion: This randomized controlled study provides evidence of improved speech recognition and psychosocial outcomes following 6 weeks of TeleAR intervention. For adult post-lingually deafened CI users, including those >3 months post-activation, AR treatment can leverage neuroplasticity to maximize outcomes., Level of Evidence: 2 Laryngoscope, 134:1861-1867, 2024., (© 2023 The American Laryngological, Rhinological and Otological Society, Inc.)

If a quantum dot is coupled to a topological superconductor via tunneling contacts, each contact hosts a Majorana zero mode in the limit of zero transmission. Close to a resonance and at a finite contact transparency, the resonant level in the quantum dot couples the Majorana modes, but a ground-state degeneracy per fermion parity subspace remains if the number of Majorana modes coupled to the dot is five or larger. Upon varying shape-defining gate voltages while remaining close to resonance, a nontrivial evolution within the degenerate ground-state manifold is achieved. We characterize the corresponding non-Abelian holonomy for a quantum dot with chaotic classical dynamics using random matrix theory and discuss measurable signatures of the non-Abelian time evolution.

In analogy to conventional semiconductor diodes, the Josephson diode exhibits superconducting properties that are asymmetric in applied bias. The effect has been investigated in a number of systems recently, and requires a combination of broken time-reversal and inversion symmetries. We demonstrate a dual of the usual Josephson diode effect, a nonreciprocal response of Andreev bound states to a superconducting phase difference across the normal region of a superconductor-normal-superconductor Josephson junction, fabricated using an epitaxial InAs/Al heterostructure. Phase asymmetry of the subgap Andreev spectrum is absent in the absence of in-plane magnetic field and reaches a maximum at 0.15 T applied in the plane of the junction transverse to the current direction. We interpret the phase diode effect in this system as resulting from finite-momentum Cooper pairing due to orbital coupling to the in-plane magnetic field. At higher magnetic fields, we observe a sign reversal of the diode effect that appears together with a reopening of the spectral gap. Within our model, the sign reversal of the diode effect at higher fields is correlated with a topological phase transition that requires Zeeman and spin-orbit interactions in addition to orbital coupling.

Background and Aim: Patients with inflammatory bowel disease (IBD) treated with thiopurines are at increased risk of keratinocyte skin cancer (KSC). Most international guidelines recommend yearly dermatological screening of thiopurine-treated patients. Whether the association between the development of KSC and the use of thiopurines is dose-dependent remains unclear. The aim of this study was to investigate the association between the cumulative thiopurine dose and KSC development in patients with IBD which can be helpful to assist in further skin cancer risk stratification and personalization of screening recommendations in patients with IBD., Methods: We performed a single-center case-control study, including patients with IBD with and without a history of KSC (cases and controls, respectively). The primary outcome was the association of cumulative azathioprine, mercaptopurine and thioguanine dose with KSC development. Univariable and multivariable logistic regression analyses were performed, the latter corrected for age and smoking, known risk factors of KSC., Results: We included 50 cases and 150 controls, predominantly white population. Age and current azathioprine use were univariably significantly associated with KSC development. In multivariable logistic regression analyses, age at inclusion remained significantly associated. Cumulative doses of thiopurines (separate or combined) or duration of thiopurine use did not impact KSC risk, also after correcting for age and smoking., Conclusion: Cumulative thiopurine dose and duration did not show an association with KSC development. Future KSC risk stratification, based on all available KSC risk factors, may aid in selecting individuals who can benefit most from dermatologic screening programs., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Carbon dioxide (CO 2 ) emissions from industrial processes, power generation, and transportation contribute significantly to global warming and climate change. Carbon capture and storage (CCS) technologies are essential to reduce these emissions and mitigate the effects of climate change. Cyclodextrins (CDs), cyclic oligosaccharides, are studied as potential CO 2 capture agents due to their unique molecular structures and high selectivity towards CO 2 . In this paper we have investigated binding efficiency of a number of cyclodextrins towards CO 2 . It is found that the crystal structure of α-cyclodextrin with CO 2 has a 1:1 stoichioimetry and that a number of simple and modified cyclodextrins bind CO 2 in water with a K g of 0.18-1.2 bar -1 (7-35 M -1 ) with per- O -methyl α-cyclodextrin having the highest CO 2 affinity., (Copyright © 2023, Jessen et al.)

Herein, we report choline chloride-based deep eutectic solvents (DESs) promoted conversion of N -acetyl-d-glucosamine (GlcNAc) into nitrogen-containing compounds, i.e., 3-acetamido-5-(1',2'-dihydroxyethyl) furan (Chromogen III) and 3-acetamido-5-acetylfuran (3A5AF). The binary deep eutectic solvent choline chloride-glycerin (ChCl-Gly), was found to promote the dehydration of GlcNAc to form Chromogen III, which reaches a maximum yield of 31.1%. On the other hand, the ternary deep eutectic solvent, choline chloride-glycerol-B(OH) 3 (ChCl-Gly-B(OH) 3 ), promoted the further dehydration of GlcNAc into 3A5AF with a maximum yield of 39.2%. In addition, the reaction intermediate, 2-acetamido-2,3-dideoxy-d- erythro -hex-2-enofuranose (Chromogen I), was detected by in situ nuclear magnetic resonance (NMR) techniques when promoted by ChCl-Gly-B(OH) 3 . The experimental results of the 1 H NMR chemical shift titration showed ChCl-Gly interactions with α-OH-3 and α-OH-4 of GlcNAc, which is responsible for promoting the dehydration reaction. Meanwhile, the strong interaction between Cl - and GlcNAc was demonstrated by 35 Cl NMR., Competing Interests: The authors declare no competing interests., (© 2023 The Author(s).)

A new way of performing reaction optimization within carbohydrate chemistry is presented. This is done by performing closed-loop optimization of regioselective benzoylation of unprotected glycosides using Bayesian optimization. Both 6- O -monobenzoylations and 3,6- O -dibenzoylations of three different monosaccharides are optimized. A novel transfer learning approach, where data from previous optimizations of different substrates is used to speed up the optimizations, has also been developed. The optimal conditions found by the Bayesian optimization algorithm provide new insight into substrate specificity, as the conditions found are significantly different. In most cases, the optimal conditions include Et 3 N and benzoic anhydride, a new reagent combination for these reactions, discovered by the algorithm, demonstrating the power of this concept to widen the chemical space. Further, the developed procedures include ambient conditions and short reaction times., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Andreev bound states with opposite phase-inversion asymmetries are observed in local tunneling spectra at the two ends of a superconductor-semiconductor-superconductor planar Josephson junction in the presence of a perpendicular magnetic field, while the nonlocal spectra remain phase symmetric. Spectral signatures agree with a theoretical model, yielding a physical picture in which phase textures in superconducting leads localize and control the position of Andreev bound states in the junction, demonstrating a simple means of controlling the position and size of Andreev states within a planar junction.

We report simultaneously acquired local and nonlocal transport spectroscopy in a phase-biased planar Josephson junction based on an epitaxial InAs-Al hybrid two-dimensional heterostructure. Quantum point contacts at the junction ends allow measurement of the 2×2 matrix of local and nonlocal tunneling conductances as a function of magnetic field along the junction, phase difference across the junction, and carrier density. A closing and reopening of a gap was observed in both the local and nonlocal tunneling spectra as a function of magnetic field. For particular tunings of junction density, gap reopenings were accompanied by zero-bias conductance peaks (ZBCPs) in local conductances. End-to-end correlation of gap reopening was strong, while correlation of local ZBCPs was weak. A model of the device, with disorder treated phenomenologically, shows comparable conductance matrix behavior associated with a topological phase transition. Phase dependence helps distinguish possible origins of the ZBCPs.

Protected 2-O-benzyolated glycosyl formates were synthesized in one-step from the corresponding orthoester using formic acid as the sole reagent. Glucopyranosyl, mannopyranosyl and galactopyranosyl donors were synthesized and their glycosylation properties studied using model glycosyl acceptors of varied steric bulk and reactivity. Bismuth triflate was the preferred catalyst and KPF 6 was used as an additive. The 1,2-trans-selectivities resulting from neighboring-group participation were excellent and the glycosylations were generally high-yielding.

One of the most intriguing aspects of synthetic chemistry is the interplay of numerous dependent and independent variables en route to achieve a successful, high-yielding chemical transformation. The experienced synthetic chemist will probe many of these variables during reaction development and optimization, which will routinely involve investigation of reaction temperature, solvent, stoichiometry, concentration, time, choice of catalyst, addition sequence or quenching conditions just to name some commonly addressed variables. Remarkably, little attention is typically given to the choice of reaction vessel material as the surface of common laboratory borosilicate glassware is, incorrectly, assumed to be chemically inert. When reviewing the scientific literature, careful consideration of the vessel material is typically only given during the use of well-known glass-etching reagents such as HF, which is typically only handled in HF-resistant, polyfluorinated polymer vessels. However, there are examples of chemical transformations that do not involve such reagents but are still clearly influenced by the choice of reaction vessel material. In the following review, we wish to condense the most significant examples of vessel effects during chemical transformations as well as observations of container-dependent stability of certain molecules. While the primary focus is on synthetic organic chemistry, relevant examples from inorganic chemistry, polymerization reactions, atmospheric chemistry and prebiotic chemistry are also covered., Competing Interests: The authors declare no conflict of interest., (This journal is © The Royal Society of Chemistry.)

Despite many years of invention, the field of carbohydrate chemistry remains rather inaccessible to non-specialists, which limits the scientific impact and reach of the discoveries made in the field. Aiming to increase the availability of stereoselective glycosylation chemistry for non-specialists, we have discovered that several commercially available pyrylium salts catalyze stereoselective O-glycosylations of a wide range of phenols and alkyl alcohols. This catalytic reaction utilizes trichloroacetimidates, an easily accessible and synthetically proven electrophile, takes place under air and only initiates when all three reagents are mixed, which should provide better reproducibility by non-specialists. The reaction exhibits varying degrees of stereospecificity, resulting in β-selective glycosylations from α-trichloroacetimidates, whilst an α-selective glycosylation proceeds from β-trichloroacetimidates. A mechanistic study revealed that the reaction likely proceeds via an S N 2-like substitution on the protonated electrophile., (© 2021 Wiley-VCH GmbH.)

Glycosylations were carried out with the two glycosyl donors 4-O-acetyl-2,3-O-isopropylidene-1-O-trichloroacetimidoyl-α-l-rhamnopyranose and 2,3,4-tri-O-benzyl-1-O-trichloro-acetimidoyl-α-l-rhamnopyranose in combination with the two alcohols 1-adamantanol and l-menthol as model glycosyl acceptors. As catalysts, the five lithium salts LiNTf 2 , LiI, LiClO 4 , LiPF 6 and LiOTf were investigated. We demonstrated that both lithium and the respective counterions are playing a role in the activation of trichloroacetimidate glycosyl donors at rt. Under these very mild conditions, the glycosylations are slow and completed in two to eight days. Depending on the counterion, the rate and yield of the reaction differs; however, the selectivity of all investigated lithium salts is deficient., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Despite being used as an anti-leukemic drug, the poor solubility of 6-mercaptopurine (6-MP) limits its use in topical and parenteral applications. Dendrimers are commonly used as drug carriers to improve their solubility in aqueous solution. In this work, the interactions between 6-MP and the amine-terminated poly(amidoamine) dendrimers (PAMAM-NH 2 ) were investigated by various NMR technology. The chemical shift titrations disclosed that the 6-MP interacted with the surface of PAMAM-NH 2 mainly through electrostatics. The determination of diffusion coefficient and relaxation measurements further confirmed the presence of interactions in 6-MP/PAMAM-NH 2 complexes. In addition, the encapsulation of 6-MP within the cavity of PAMAM-NH 2 was revealed through nuclear Overhauser effect spectroscopy and Saturation Transfer Double Difference analysis. Finally, the binding strength (H-8 is 100% and H-2 is 70%) of 6-MP to PAMAM-NH 2 was quantitatively expressed using epitope maps. This study provides a systematic methodology for qualitative and quantitative studies of the interactions between dendrimers and drug molecules in general., (© 2021 Wiley-VCH GmbH.)

Liposomes are versatile three-dimensional, biomaterial-based frameworks that can spatially enclose a variety of organic and inorganic biomaterials for advanced targeted-delivery applications. Implementation of external-stimuli-controlled release of their cargo will significantly augment their wide application for liposomal drug delivery. This paper presents the synthesis of a carbohydrate-derived lipid, capable of changing its conformation depending on the presence of Zn 2+ : an active state in the presence of Zn 2+ ions and back to an inactive state in the absence of Zn 2+ or when exposed to Na 2 EDTA, a metal chelator with high affinity for Zn 2+ ions. This is the first report of a lipid triggered by the presence of a metal chelator. Total internal reflection fluorescence microscopy and a single-liposome study showed that it indeed was possible for the lipid to be incorporated into the bilayer of stable liposomes that remained leakage-free for the fluorescent cargo of the liposomes. On addition of EDTA to the liposomes, their fluorescent cargo could be released as a result of the membrane-incorporated lipids undergoing a conformational change., (© 2021 Wiley-VCH GmbH.)

Background: Increasing numbers of adults are receiving cochlear implants (CIs) and many achieve high levels of speech perception and improved quality of life. However, a proportion of implant recipients still struggle due to limited speech recognition and/or greater communication demands in their daily lives. For these individuals a program of aural rehabilitation (AR) has the potential to improve outcomes., Purpose: The study investigated the effects of a short-term AR intervention on speech recognition, functional communication, and psychosocial outcomes in post lingually deafened adult CI users., Research Design: The experimental design was a multisite clinical study with participants randomized to either an AR treatment or active control group. Each group completed 6 weekly 90-minute individual treatment sessions. Assessments were completed pretreatment, 1 week and 2 months post-treatment., Study Sample: Twenty-five post lingually deafened adult CI recipients participated. AR group: mean age 66.2 (48-80); nine females, four males; months postactivation 7.7 (3-16); mean years severe to profound deafness 18.4 (2-40). Active control group: mean age 62.8 (47-85); eight females, four males; months postactivation 7.0 (3-13); mean years severe to profound deafness 18.8 (1-55)., Intervention: The AR protocol consisted of auditory training (words, sentences, speech tracking), and psychosocial counseling (informational and communication strategies). Active control group participants engaged in cognitive stimulation activities (e.g., crosswords, sudoku, etc.)., Data Collection and Analysis: Repeated measures ANOVA or analysis of variance, MANOVA or multivariate analysis of variance, and planned contrasts were used to compare group performance on the following measures: CasperSent; Hearing Handicap Inventory; Nijmegen Cochlear Implant Questionnaire; Client Oriented Scale of Improvement; Glasgow Benefit Inventory., Results: The AR group showed statistically significant improvements on speech recognition performance, psychosocial function, and communication goals with no significant improvement seen in the control group. The two groups were statistically equivalent on all outcome measures at preassessment. The robust improvements for the AR group were maintained at 2 months post-treatment., Conclusion: Results of this clinical study provide evidence that a short-term AR intervention protocol can maximize outcomes for adult post lingually deafened CI users. The impact of this brief multidimensional AR intervention to extend CI benefit is compelling, and may serve as a template for best practices with adult CI users., Competing Interests: None declared., (American Academy of Audiology. This article is published by Thieme.)

A method for introducing dimethylphenylsilyl at the 4-position in carbohydrates has been developed. Two C-silylated glycosyl donors were prepared via levoglucosenone, starting from cellulose. The glycosylation properties were studied using three glucoside acceptors, a 3-OH, 4-OH, and 6-OH. Compared with the 4-deoxy variant, it was found that the anomeric selectivity was influenced more by the C-2 substituents orientation than the silyl in the 4-position. In general, the reactivity of these donors was higher than the corresponding 4-deoxy-analogue, albeit a competition experiment showed that the introduction of a C-Si increases the relative reactivity by a modest factor of around two., (© 2020 Wiley-VCH GmbH.)

We investigate transmon qubits made from semiconductor nanowires with a fully surrounding superconducting shell. In the regime of reentrant superconductivity associated with the destructive Little-Parks effect, numerous coherent transitions are observed in the first reentrant lobe, where the shell carries 2π winding of superconducting phase, and are absent in the zeroth lobe. As junction density was increased by gate voltage, qubit coherence was suppressed then lost in the first lobe. These observations and numerical simulations highlight the role of winding-induced Andreev states in the junction.

In this paper we describe the synthesis of a new carbohydrate-based building block functionalized with azido or amino groups on the 2 and 4 positions. The building block can be synthesized in anomerically pure form in only five scalable steps starting from commercially available levoglucosan. It was shown that the building block could undergo alkylations under strongly basic conditions. The building block with azido groups could furthermore take part in CuAAC reactions, generating derivatives with ester or carboxylic acid functionalities. In addition, the anomeric mixture of the building block was used for the synthesis of a molecule that could act as an emulsifier only in the presence of Zn 2+ ions., (Copyright © 2020, Holmstrøm et al.; licensee Beilstein-Institut.)

A semiconductor transmon with an epitaxial Al shell fully surrounding an InAs nanowire core is investigated in the low E&#95;{J}/E&#95;{C} regime. Little-Parks oscillations as a function of flux along the hybrid wire axis are destructive, creating lobes of reentrant superconductivity separated by a metallic state at a half quantum of applied flux. In the first lobe, phase winding around the shell can induce topological superconductivity in the core. Coherent qubit operation is observed in both the zeroth and first lobes. Splitting of parity bands by coherent single-electron coupling across the junction is not resolved beyond line broadening, placing a bound on Majorana coupling, E&#95;{M}/h<10  MHz, much smaller than the Josephson coupling E&#95;{J}/h∼4.7  GHz.

An odd-occupied quantum dot in a Josephson junction can flip transmission phase, creating a π junction. When the junction couples topological superconductors, no phase flip is expected. We investigate this and related effects in a full-shell hybrid interferometer, using gate voltage to control dot-junction parity and axial magnetic flux to control the transition from trivial to topological superconductivity. Enhanced zero-bias conductance and critical current for odd parity in the topological phase reflects hybridization of the confined spin with zero-energy modes in the leads.

Coherence of superconducting qubits can be improved by implementing designs that protect the parity of Cooper pairs on superconducting islands. Here, we introduce a parity-protected qubit based on voltage-controlled semiconductor nanowire Josephson junctions, taking advantage of the higher harmonic content in the energy-phase relation of few-channel junctions. A symmetric interferometer formed by two such junctions, gate-tuned into balance and frustrated by a half-quantum of applied flux, yields a cos(2φ) Josephson element, reflecting coherent transport of pairs of Cooper pairs. We demonstrate that relaxation of the qubit can be suppressed tenfold by tuning into the protected regime.

Majorana zero modes are leading candidates for topological quantum computation due to non-local qubit encoding and non-abelian exchange statistics. Spatially separated Majorana modes are expected to allow phase-coherent single-electron transport through a topological superconducting island via a mechanism referred to as teleportation. Here we experimentally investigate such a system by patterning an elongated epitaxial InAs-Al island embedded in an Aharonov-Bohm interferometer. With increasing parallel magnetic field, a discrete sub-gap state in the island is lowered to zero energy yielding persistent 1e-periodic Coulomb blockade conductance peaks (e is the elementary charge). In this condition, conductance through the interferometer is observed to oscillate in a perpendicular magnetic field with a flux period of h/e (h is Planck's constant), indicating coherent transport of single electrons through the islands, a signature of electron teleportation via Majorana modes.

We demonstrate strong suppression of charge dispersion in a semiconductor-based transmon qubit across Josephson resonances associated with a quantum dot in the junction. On resonance, dispersion is drastically reduced compared to conventional transmons with corresponding Josephson and charging energies. We develop a model of qubit dispersion for a single-channel resonance, which is in quantitative agreement with experimental data.

We demonstrate concomitant measurement of phase-dependent critical current and Andreev bound state spectrum in a highly transmissive InAs Josephson junction embedded in a dc superconducting quantum interference device (SQUID). Tunneling spectroscopy reveals Andreev bound states with near unity transmission probability. A nonsinusoidal current-phase relation is derived from the Andreev spectrum, showing excellent agreement with the one extracted from the SQUID critical current. Both measurements are reconciled within a short junction model where multiple Andreev bound states, with various transmission probabilities, contribute to the entire supercurrent flowing in the junction.

Hybrid semiconductor-superconductor nanowires have emerged as a promising platform for realizing topological superconductivity (TSC). Here, we present a route to TSC using magnetic flux applied to a full superconducting shell surrounding a semiconducting nanowire core. Tunneling into the core reveals a hard induced gap near zero applied flux, corresponding to zero phase winding, and a gapped region with a discrete zero-energy state around one applied flux quantum, corresponding to 2π phase winding. Theoretical analysis indicates that the winding of the superconducting phase can induce a transition to a topological phase supporting Majorana zero modes. Measured Coulomb blockade peak spacing around one flux quantum shows a length dependence that is consistent with the existence of Majorana modes at the ends of the nanowire., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Six N-(o-methoxyphenyl)trifluoroacetimidate glycosyl donors have been synthesized and their role as glycosyl donors has been investigated. The donors were synthesized with complete β-selectivity, except in one case, and were found to be stable. When Bi(OTf)3, Fe(OTf)2, and Zn(OTf)2 were employed as catalysts, the glycosylations were found to be highly α-selective in Et2O. The selectivity and reaction rate changed with a change in the acceptor reactivity.

Creating a transmon qubit using semiconductor-superconductor hybrid materials not only provides electrostatic control of the qubit frequency, it also allows parts of the circuit to be electrically connected and disconnected in situ by operating a semiconductor region of the device as a field-effect transistor. Here, we exploit this feature to compare in the same device characteristics of the qubit, such as frequency and relaxation time, with related transport properties such as critical supercurrent and normal-state resistance. Gradually opening the field-effect transistor to the monitoring circuit allows the influence of weak-to-strong dc monitoring of a "live" qubit to be measured. A model of this influence yields excellent agreement with experiment, demonstrating a relaxation rate mediated by a gate-controlled environmental coupling.

We present conductance-matrix measurements of a three-terminal superconductor-semiconductor hybrid device consisting of two normal leads and one superconducting lead. Using a symmetry decomposition of the conductance, we find that antisymmetric components of pairs of local and nonlocal conductances qualitatively match at energies below the superconducting gap, and we compare this finding with symmetry relations based on a noninteracting scattering matrix approach. Further, the local charge character of Andreev bound states is extracted from the symmetry-decomposed conductance data and is found to be similar at both ends of the device and tunable with gate voltage. Finally, we measure the conductance matrix as a function of magnetic field and identify correlated splittings in low-energy features, demonstrating how conductance-matrix measurements can complement traditional single-probe measurements in the search for Majorana zero modes.

Nanowires can serve as flexible substrates for hybrid epitaxial growth on selected facets, allowing for the design of heterostructures with complex material combinations and geometries. In this work we report on hybrid epitaxy of freestanding vapor-liquid-solid grown and in-plane selective area grown semiconductor-ferromagnetic insulator-superconductor (InAs/EuS/Al) nanowire heterostructures. We study the crystal growth and complex epitaxial matching of wurtzite and zinc-blende InAs/rock-salt EuS interfaces as well as rock-salt EuS/face-centered cubic Al interfaces. Because of the magnetic anisotropy originating from the nanowire shape, the magnetic structure of the EuS phase is easily tuned into single magnetic domains. This effect efficiently ejects the stray field lines along the nanowires. With tunnel spectroscopy measurements of the density of states, we show that the material has a hard induced superconducting gap, and magnetic hysteretic evolution which indicates that the magnetic exchange fields are not negligible. These hybrid nanowires fulfill key material requirements for serving as a platform for spin-based quantum applications, such as scalable topological quantum computing.

Glycosyl donors functionalized with 2,2'-bipyridine moieties on the 3-OH and 6-OH or the 2-OH and 4-OH undergo a conformational change when forming 1:1 complexes with Zn 2+ ions. The pyranoside ring of the zinc complexes adopted axial-rich skew boat conformations. The reactivities of the two glycosyl donors were investigated by performing a series of glycosylations in the presence or absence of Zn 2+ ions. These glycosylations suggested a decrease in reactivity when binding Zn 2+ . The conformational effect of binding Zn 2+ was therefore studied using a third glycosyl donor, unable to undergo conformational changes when binding Zn 2+ . From competition experiments, it was observed that the binding-induced conformational change increased the reactivity slightly compared to the glycosyl donor unable to undergo a conformational change.

The Fischer-Tropsch (FT) process is a practical approach to convert synthesis gas (CO and H 2 ) into hydrocarbons and oxygenates, and these product mixtures are usually well-characterized. However, the analysis of Fischer-Tropsch waste water (FTW) is still somewhat underdeveloped and the exact composition of FTW remains unclear. Herein, various qualitative NMR techniques, especially diffusion-ordered spectroscopy (DOSY) and one dimension (1D) selective gradient total correlation spectroscopy (SelTOCSY) were strategically applied in the analysis of FTW. The NMR results show that the DOSY technique can pseudo-separate most of components in complex mixtures over the diffusion dimension. The SelTOCSY technique is used as a supporting method in the cases where the DOSY technique cannot clearly distinguish overlapped signals. Moreover, the quantitative 1 H NMR (qNMR) was further used to quantify the components of the sample. These routine and advanced qualitative and quantitative NMR technique utilized here provide a fast, effective and feasible method for the identification of complex mixtures in FTW, which might be a powerful and fast alternative to gas chromatography or high performance liquid chromatography for FTW research., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Quantum dot arrays are a versatile platform for the implementation of spin qubits, as high-bandwidth sensor dots can be integrated with single-, double-, and triple-dot qubits yielding fast and high-fidelity qubit readout. However, for undoped silicon devices, reflectometry off sensor ohmics suffers from the finite resistivity of the two-dimensional electron gas (2DEG), and alternative readout methods are limited to measuring qubit capacitance, rather than qubit charge. By coupling a surface-mount resonant circuit to the plunger gate of a high-impedance sensor, we realized a fast charge sensing technique that is compatible with resistive 2DEGs. We demonstrate this by acquiring at high speed charge stability diagrams of double- and triple-dot arrays in Si/SiGe heterostructures as well as pulsed-gate single-shot charge and spin readout with integration times as low as 2.4 μs.

One-dimensional (1D) electronic transport and induced superconductivity in semiconductor nanostructures are crucial ingredients to realize topological superconductivity. Our approach for topological superconductivity employs a two-dimensional electron gas (2DEG) formed by an InAs quantum well, cleanly interfaced with an epitaxial superconductor (epi-Al). This epi-Al/InAs quantum well heterostructure is advantageous for fabricating large-scale nanostructures consisting of multiple Majorana zero modes. Here, we demonstrate transport studies of building-blocks using a high-quality epi-Al/InAs 2DEG heterostructure, which could be put together to realize various proposed 1D nanowire-based nanostructures and 2DEG-based networks that could host multiple Majorana zero modes. The studies include (1) gate-defined quasi-1D channels in the InAs 2DEG and (2) quantum point contacts for tunneling spectroscopy, as well as induced superconductivity in (3) a ballistic Al-InAs 2DEG-Al Josephson junction. From 1D transport, systematic evolution of conductance plateaus in half-integer conductance quanta is observed with Landé g-factor of 17, indicating the strong spin-orbit coupling and high quality of the InAs 2DEG. The improved 2DEG quality leads to ballistic Josephson junctions with enhanced characteristic parameters such as I c R n and I exc R n , the product of superconducting critical current I c (and excess current I exc ) and normal resistance R n . Our results of electronic transport studies based on the 2D approach suggest that the epitaxial superconductor/2D semiconductor system with improved 2DEG quality is suitable for realizing large-scale nanostructures for quantum computing applications.

Majorana zero modes-quasiparticle states localized at the boundaries of topological superconductors-are expected to be ideal building blocks for fault-tolerant quantum computing 1,2 . Several observations of zero-bias conductance peaks measured by tunnelling spectroscopy above a critical magnetic field have been reported as experimental indications of Majorana zero modes in superconductor-semiconductor nanowires 3-8 . On the other hand, two-dimensional systems offer the alternative approach of confining Majorana channels within planar Josephson junctions, in which the phase difference φ between the superconducting leads represents an additional tuning knob that is predicted to drive the system into the topological phase at lower magnetic fields than for a system without phase bias 9,10 . Here we report the observation of phase-dependent zero-bias conductance peaks measured by tunnelling spectroscopy at the end of Josephson junctions realized on a heterostructure consisting of aluminium on indium arsenide. Biasing the junction to φ ≈ π reduces the critical field at which the zero-bias peak appears, with respect to φ = 0. The phase and magnetic-field dependence of the zero-energy states is consistent with a model of Majorana zero modes in finite-size Josephson junctions. As well as providing experimental evidence of phase-tuned topological superconductivity, our devices are compatible with superconducting quantum electrodynamics architectures 11 and are scalable to the complex geometries needed for topological quantum computing 9,12,13 .

A stereoselective and self-promoted glycosylation for the synthesis of various N -glycosides and glycosyl sulfonamides from trichloroacetimidates is presented. No additional catalysts or promoters are needed in what is essentially a two-component reaction. When α-glucosyl trichloroacetimidates are employed, the reaction resulted in the stereospecific formation of the corresponding β- N -glucosides in high yields at ambient conditions. On the other hand, when equatorial glucosyl donors were used, the stereospecificity decreased and resulted in a mixture of anomers. By NMR-studies, it was concluded that this decrease in stereospecificity was due to an, until now, unpresented anomerization of the trichloroacetimidate under the very mildly acidic conditions. The mechanism and kinetics of the glycosylations have been studied by NMR-experiments, which gave an insight into the activation of trichloroacetimidates, suggesting an S N i-like mechanism involving ion pairs. The scope of glycosyl donors and sulfonamides was found to be very broad including popular N -protective groups and common glycosyl donors of various reactivity. Peracetylated GlcNAc trichloroacetimidate could be used without the need for any promotors or additives and a tyrosine side chain was glycosylated as an N -glycosyl carbamate. The N -carbamates and the N -sulfonyl groups functioned as orthogonal protective groups of the N -glycoside and hence allowed further N -functionalization without risking mutarotation of the N -glycoside. The N -glycosylation was also performed on a gram scale, without a drop in stereoselectivity nor yield.

Scalable quantum processors require tunable two-qubit gates that are fast, coherent and long-range. The Heisenberg exchange interaction offers fast and coherent couplings for spin qubits, but is intrinsically short-ranged. Here, we demonstrate that its range can be increased by employing a multielectron quantum dot as a mediator, while preserving speed and coherence of the resulting spin-spin coupling. We do this by placing a large quantum dot with 50-100 electrons between a pair of two-electron double quantum dots that can be operated and measured simultaneously. Two-spin correlations identify coherent spin-exchange processes across the multielectron quantum dot. We further show that different physical regimes of the mediated exchange interaction allow a reduced susceptibility to charge noise at sweet spots, as well as positive and negative coupling strengths up to several gigahertz. These properties make multielectron dots attractive as scalable, voltage-controlled coherent coupling elements.

We present measurements of one-dimensional superconductor-semiconductor Coulomb islands, fabricated by gate confinement of a two-dimensional InAs heterostructure with an epitaxial Al layer. When tuned via electrostatic side gates to regimes without subgap states, Coulomb blockade reveals Cooper-pair mediated transport. When subgap states are present, Coulomb peak positions and heights oscillate in a correlated way with magnetic field and gate voltage, as predicted theoretically, with (anti)crossings in (parallel) transverse magnetic field indicating Rashba-type spin-orbit coupling. Overall results are consistent with a picture of overlapping Majorana zero modes in finite wires.

The motif α-D-Gal p NAc-(1-3)-D-Gal p NAc is very common in Nature and hence its synthesis highly relevant. The synthesis of its azido precursor has been studied and optimized in terms of steps, yields and selectivity. It has been found that glycosylation of the 3,4-diol acceptor is an advantage over the use of a 4- O -protected acceptor and that both regio- and anomeric selectivity is enhanced by bulky 6- O -protective groups. The acceptors and donors are made from common building blocks, limiting protective manipulations, and in this context, unavoidable side reactions.