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Vibrational polaritons, which have been primarily studied in Fabry-Pérot cavities with a large number of molecules (N â¼ 106-1010) coupled to the resonator mode, exhibit various experimentally observed effects on chemical reactions. However, the exact mechanism is elusively understood from the theoretical side, as the large number of molecules involved in an experimental strong coupling condition cannot be represented completely in simulations. This discrepancy between theory and experiment arises from computational descriptions of polariton systems typically being limited to only a few molecules, thus failing to represent the experimental conditions adequately. To address this mismatch, we used surface phonon polariton (SPhP) resonators as an alternative platform for vibrational strong coupling. SPhPs exhibit strong electromagnetic confinement on the surface and thus allow for coupling to a small number of molecules. As a result, this platform can enhance nonlinearity and slow down relaxation to the dark modes. In this study, we fabricated a pillar-shaped quartz resonator and then coated it with a thin layer of cobalt phthalocyanine (CoPc). By employing scattering-type scanning near-field optical microscopy (s-SNOM), we spatially investigated the dependency of vibrational strong coupling on the spatially varying electromagnetic field strength and demonstrated strong coupling with 38,000 molecules only-reaching to the small N limit. Through s-SNOM analysis, we found that strong coupling was observed primarily on the edge of the quartz pillar and the apex of the s-SNOM tip, where the maximum field enhancement occurs. In contrast, a weak resonance signal and lack of coupling were observed closer to the center of the pillar. This work demonstrates the importance of spatially resolved polariton systems in nanophotonic platforms and lays a foundation to explore polariton chemistry and chemical dynamics at the small N limit-one step closer to reconcile with high-level quantum calculations.
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One of the central aims of the field of spintronics is the control of individual electron spins to effectively manage the transmission of quantized data. One well-known mechanism for controlling electronic spin transport is the chiral-induced spin-selectivity (CISS) effect in which a helical nanostructure imparts a preferential spin orientation on the electronic transport. One potential application of the CISS effect is as a transduction pathway between electronic spin and circularly polarized light within nonreciprocal photonic devices. In this work, we identify and quantify the degree of chiral-induced spin-selective electronic transport in helical polyaniline films using magnetoconductive atomic force microscopy (mcAFM). We then induce circularly polarized quantum light emission from CdSe/CdS core/shell quantum dots placed on these films, demonstrating a degree of circular polarization of up to â¼21%. Utilizing time-resolved photoluminescence microscopy, we measure the radiative lifetime difference associated with left- and right-handed circular polarizations of single emitters. These lifetime differences, in combination with Kelvin probe mapping of the variation of surface potential with magnetization of the substrate, help establish an energy level diagram describing the spin-dependent transport pathways that enable the circularly polarized photoluminescence.
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BACKGROUND: Pleural procedures are essential for the investigation and management of pleural disease and can be associated with significant morbidity and mortality. There is a lack of pleural procedure complication data in the Australian and New Zealand region. AIMS: To review pleural procedure practices at Wollongong Hospital with an emphasis on the assessment of complications, use of thoracic ultrasound (TUS), pathology results and comparison of findings with international data. METHODS: Retrospective analysis of medical records was performed on pleural procedures identified through respiratory specialist trainee logbooks at Wollongong Hospital from January 2018 to December 2021. Comparison of complication rates was made to the British Thoracic Society 2011 a national pleural audit. RESULTS: One hundred and twenty-one pleural procedures were identified. There were 71 chest drains, 49 thoracocentesis and one indwelling pleural catheter (IPC) insertion. Ninety-seven per cent of procedures were performed for pleural effusions and 3% for pneumothorax. This audit demonstrated a complication rate (excluding pain) of 16.9% for chest drains and 4.1% for thoracocentesis. This gave an overall complication event rate of 10.8% (excluding pain) for pleural procedures. There was no major bleeding, organ puncture, pleural space infection or death. Bedside TUS was used in 99% of procedures. CONCLUSION: Complication rates for pleural procedures performed by respiratory specialist trainees at Wollongong Hospital are comparable with international outcomes. This audit provides data for comparison on pleural procedure complication rates in Australia. Future studies are required to determine complication rates with IPCs.
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Enfermedades Pleurales , Derrame Pleural Maligno , Derrame Pleural , Humanos , Estudios Retrospectivos , Resultado del Tratamiento , Australia/epidemiología , Derrame Pleural/diagnóstico por imagen , Derrame Pleural/epidemiología , Derrame Pleural/terapia , Enfermedades Pleurales/epidemiología , Enfermedades Pleurales/terapia , Hospitales de Enseñanza , Dolor , Catéteres de Permanencia/efectos adversos , Derrame Pleural Maligno/etiologíaRESUMEN
A gold surface is functionalized by chemisorption of the enantiopure N,N'-bis-[2,2';5',2â³]tert-thiophene-5-yl methylcyclohexane-1,2-diamine (2T3N), a chiral oligothiophene derivative, via overnight incubation in a 2T3N ethanol solution. The Au|2T3N interface is characterized by x-ray photoelectron circular dichroism and comparing x-ray photoemission spectroscopy and electro-desorption results. Charge transmission at the Au|2T3N| solution interface is characterized by recording the cyclic voltammetry of the Fe(III)/Fe(II) reversible redox couple, finding a charge transfer rate constant, k°, variation from 1 × 10-1 to 3.3 × 10-2 cm s-1, when comparing the bare Au and the Au|2T3N interfaces, respectively. The "anomalous" high value of k° found for the chiral Au|2T3N interface can be rationalized on the basis of the chiral-induced spin selectivity effect, as further proved by magnetic-conductive atomic force microscopy measurements at room temperature. A spin polarization of about 30% is found.
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Quantum light emitters capable of generating single photons with circular polarization and non-classical statistics could enable non-reciprocal single-photon devices and deterministic spin-photon interfaces for quantum networks. To date, the emission of such chiral quantum light relies on the application of intense external magnetic fields, electrical/optical injection of spin-polarized carriers/excitons or coupling with complex photonic metastructures. Here we report the creation of free-space chiral quantum light emitters via the nanoindentation of monolayer WSe2/NiPS3 heterostructures at zero external magnetic field. These quantum light emitters emit with a high degree of circular polarization (0.89) and single-photon purity (95%), independent of pump laser polarization. Scanning diamond nitrogen-vacancy microscopy and temperature-dependent magneto-photoluminescence studies reveal that the chiral quantum light emission arises from magnetic proximity interactions between localized excitons in the WSe2 monolayer and the out-of-plane magnetization of defects in the antiferromagnetic order of NiPS3, both of which are co-localized by strain fields associated with the nanoscale indentations.
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Defect engineering of van der Waals semiconductors has been demonstrated as an effective approach to manipulate the structural and functional characteristics toward dynamic device controls, yet correlations between physical properties with defect evolution remain underexplored. Using proton irradiation, we observe an enhanced exciton-to-trion conversion of the atomically thin WS2. The altered excitonic states are closely correlated with nanopore induced atomic displacement, W nanoclusters, and zigzag edge terminations, verified by scanning transmission electron microscopy, photoluminescence, and Raman spectroscopy. Density functional theory calculation suggests that nanopores facilitate formation of in-gap states that act as sinks for free electrons to couple with excitons. The ion energy loss simulation predicts a dominating electron ionization effect upon proton irradiation, providing further evidence on band perturbations and nanopore formation without destroying the overall crystallinity. This study provides a route in tuning the excitonic properties of van der Waals semiconductors using an irradiation-based defect engineering approach.
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Focused ion beam implantation is ideally suited for placing defect centers in wide bandgap semiconductors with nanometer spatial resolution. However, the fact that only a few percent of implanted defects can be activated to become efficient single photon emitters prevents this powerful capability to reach its full potential in photonic/electronic integration of quantum defects. Here an industry adaptive scalable technique is demonstrated to deterministically create single defects in commercial grade silicon carbide by performing repeated low ion number implantation and in situ photoluminescence evaluation after each round of implantation. An array of 9 single defects in 13 targeted locations is successfully created-a ≈70% yield which is more than an order of magnitude higher than achieved in a typical single pass ion implantation. The remaining emitters exhibit non-classical photon emission statistics corresponding to the existence of at most two emitters. This approach can be further integrated with other advanced techniques such as in situ annealing and cryogenic operations to extend to other material platforms for various quantum information technologies.
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Electrónica , Fotones , Retroalimentación , SemiconductoresRESUMEN
Primary snoring impacts a significant portion of the adult population and has the potential to significantly impair quality of life. The purpose of these guidelines is to provide evidence-based recommendations to assist Australasian practitioners in the management of adult patients who present with primary snoring without significant obstructive sleep apnoea. The Timetable, Methodology and Standards by which this Position Statement has been established is outlined in the Appendix S1. The main recommendations are: Weight loss, and reduced alcohol consumption should be recommended, where appropriate If clinical judgement dictates, benzodiazepine and opioid reduction or avoidance may be advised Positional therapy should be considered in supine dominant snorers In dentate patients, Mandibular advancement devices (MAD) should be recommended as a first line treatment following assessment by both an appropriate Dentist and Sleep physician Continuous positive airway pressure (CPAP) devices may be recommended in patients with primary snoring in those already committed to their use or willing to try Surgical treatment of primary snoring by an appropriately credentialled surgeon may be advised and includes nasal (adjunctive), palatal and other interventions This position statement has been designed based on the best available current evidence and our combined expert clinical experience to facilitate the management of patients who present with primary snoring. It provides clinicians with a series of both non-surgical and surgical options with the aim of achieving optimal symptom control and patient outcomes. This is the first such set of recommendations to be established within Australasia and has also been reviewed and endorsed by the Australasian Sleep Association.
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Avance Mandibular , Ronquido , Adulto , Humanos , Ronquido/etiología , Ronquido/terapia , Consenso , Calidad de Vida , Avance Mandibular/métodos , SueñoRESUMEN
The cross-electrophile coupling of either twisted-amides or heteroaryl halides with alkyl halides, enabled by ball-milling, is herein described. The operationally simple nickel-catalyzed process has no requirement for inert atmosphere or dry solvents and delivers the corresponding acylated or heteroarylated products across a broad range of substrates. Key to negating the necessity of inert reaction conditions is the mechanical activation of the raw metal terminal reductant: manganese in the case of twisted amides and zinc for heteroaryl halides.
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Actinide materials have various applications that range from nuclear energy to quantum computing. Most current efforts have focused on bulk actinide materials. Tuning functional properties by using strain engineering in epitaxial thin films is largely lacking. Using uranium dioxide (UO2 ) as a model system, in this work, the authors explore strain engineering in actinide epitaxial thin films and investigate the origin of induced ferromagnetism in an antiferromagnet UO2 . It is found that UO2+ x thin films are hypostoichiometric (x<0) with in-plane tensile strain, while they are hyperstoichiometric (x>0) with in-plane compressive strain. Different from strain engineering in non-actinide oxide thin films, the epitaxial strain in UO2 is accommodated by point defects such as vacancies and interstitials due to the low formation energy. Both epitaxial strain and strain relaxation induced point defects such as oxygen/uranium vacancies and oxygen/uranium interstitials can distort magnetic structure and result in magnetic moments. This work reveals the correlation among strain, point defects and ferromagnetism in strain engineered UO2+ x thin films and the results offer new opportunities to understand the influence of coupled order parameters on the emergent properties of many other actinide thin films.
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Akiyama atomic force microscopy probes represent a unique means of combining several of the desirable properties of tuning fork and cantilever probe designs. As a hybridized mechanical resonator, the vibrational characteristics of Akiyama probes result from a complex coupling between the intrinsic vibrational eigenmodes of its constituent tuning fork and bridging cantilever components. Through a combination of finite element analysis modeling and experimental measurements of the thermal vibrations of Akiyama probes we identify a complex series of vibrational eigenmodes and measure their frequencies, quality factors, and spring constants. We then demonstrate the viability of Akiyama probes to perform bimodal multi-frequency force sensing by performing a multimodal measurement of a surface's nanoscale photothermal response using photo-induced force microscopy imaging techniques. Further performing a parametric search over alternative Akiyama probe geometries, we propose two modified probe designs to enhance the capability of Akiyama probes to perform sensitive bimodal multifrequency force sensing measurements.
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Rapid and wide-ranging developments have established mechanochemistry as a powerful avenue in sustainable organic synthesis. This is primarily due to unique opportunities which have been offered in solvent-free - or highly solvent-minimised - reaction systems. Nevertheless, despite elegant advances in ball-milling technology, limitations in scale-up still remain. This tutorial review covers the first reports into the translation from "batch-mode" ball-milling to "flow-mode" reactive extrusion, using twin-screw extrusion.
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Técnicas de Química Sintética , SolventesRESUMEN
Herein, we report a new electrochemical method for alkoxy radical generation from alcohols using a proton-coupled electron transfer (PCET) approach, showcased via the deconstructive functionalization of cycloalkanols. The electrochemical method is applicable across a diverse array of substituted cycloalkanols, accessing a broad range of synthetically useful distally functionalized ketones. The orthogonal derivatization of the products has been demonstrated through chemoselective transformations, and the electrochemical process has been performed on a gram scale in continuous single-pass flow.
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The nickel-catalyzed cross-electrophile coupling of aryl halides and alkyl halides enabled by ball-milling is herein described. Under a mechanochemical manifold, the reductive C-C bond formation was achieved in the absence of bulk solvent and air/moisture sensitive setups, in reaction times of 2 h. The mechanical action provided by ball milling permits the use of a range of zinc sources to turnover the nickel catalytic cycle, enabling the synthesis of 28 cross-electrophile coupled products.
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A new and efficient strategy for the rapid formation of novel fluorinated tetrahydropyridazines and dihydrooxazines has been developed by fluorocyclisation of ß,γ-unsaturated hydrazones and oximes with the fluoroiodane reagent. Mechanochemical synthesis delivered fluorinated tetrahydropyridazines in similar excellent yields to conventional solution synthesis, whereas fluorinated dihydrooxazines were prepared in much better yields by ball-milling.
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Solid-state single-photon sources are essential building blocks for quantum photonics and quantum information technologies. This study demonstrates promising single-photon emission from quantum defects generated in single-wall carbon nanotubes (SWCNTs) by covalent reaction with guanine nucleotides in their single-stranded DNA coatings. Low-temperature photoluminescence spectroscopy and photon-correlation measurements on individual guanine-functionalized SWCNTs (GF-SWCNTs) indicate that multiple, closely spaced guanine defect sites within a single ssDNA strand collectively form an exciton trapping potential that supports a localized quantum state capable of room-temperature single-photon emission. In addition, exciton traps from adjacent ssDNA strands are weakly coupled to give cross-correlations between their separate photon emissions. Theoretical modeling identifies coupling mechanism as a capture of band-edge excitons. Because the spatial pattern of nanotube functionalization sites can be readily controlled by selecting ssDNA base sequences, GF-SWCNTs should become a versatile family of quantum light emitters with engineered properties.
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Nanotubos de Carbono , ADN , ADN de Cadena Simple , Óptica y Fotónica , FotonesRESUMEN
Chemical reactions between semiconducting single-wall carbon nanotubes (SWCNTs) and single-stranded DNA (ssDNA) achieve spatially patterned covalent functionalization sites and create coupled fluorescent quantum defects on the nanotube surface, tailoring SWCNT photophysics for applications such as single-photon emitters in quantum information technologies. The evaluation of relaxation dynamics of photoluminescence (PL) from those coupled quantum defects is essential for understanding the nanotube electronic structure and beneficial to the design of quantum light emitters. Here, we measured the PL decay for ssDNA-functionalized SWCNTs as a function of the guanine content of the ssDNA oligo that dictates the red-shifting of their PL emission peaks relative to the band-edge exciton. We then correlate the observed dependence of PL decay dynamics on energy red-shifts to the exciton potential energy landscape, which is modeled using first-principles approaches based upon the morphology of ssDNA-altered SWCNTs obtained by atomic force microscopy (AFM) imaging. Our simulations illustrate that the multiple guanine defects introduced within a single ssDNA strand strongly interact to create a deep exciton trapping well, acting as a single hybrid trap. The emission decay from the distinctive trapping potential landscape is found to be biexponential for ssDNA-modified SWCNTs. We attributed the fast time component of the biexponential PL decay to the redistribution of exciton population among the lowest energy bright states and a manifold of dark states emerging from the coupling of multiple guanine defects. The long lifetime component in the biexponential decay, on the other hand, is attributed to the redistribution of exciton population among different exciton trapping sites that arise from the binding of multiple ssDNA strands along the nanotube axis. AFM measurements indicate that those trapping sites are separated on average by â¼8 nm along the nanotube axis.
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Nanotubos de Carbono , ADN , ADN de Cadena Simple , Microscopía de Fuerza AtómicaRESUMEN
The majority of 2D IR spectrometers operate at 1-10 kHz using Ti:Sapphire laser technology. We report a 2D IR spectrometer designed around Yb:KGW laser technology that operates shot-to-shot at 100 kHz. It includes a home-built OPA, a mid-IR pulse shaper, and custom-designed electronics with optional on-chip processing. We report a direct comparison between Yb:KGW and Ti:Sapphire based 2D IR spectrometers. Even though the mid-IR pulse energy is much lower for the Yb:KGW driven system, there is an 8x improvement in signal-to-noise over the 1 kHz Ti:Sapphire driven spectrometer to which it is compared. Experimental data is shown for sub-millimolar concentrations of amides. Advantages and disadvantages of the design are discussed, including thermal background that arises at high repetition rates. This fundamental spectrometer design takes advantage of newly available Yb laser technology in a new way, providing a straightforward means of enhancing sensitivity.