Strain-engineering in atomically thin metal dichalcogenides is a useful method for realizing single-photon emitters (SPEs) for quantum technologies. Correlating SPE position with local strain ...topography is challenging due to localization inaccuracies from the diffraction limit. Currently, SPEs are assumed to be positioned at the highest strained location and are typically identified by randomly screening narrow-linewidth emitters, of which only a few are spectrally pure. In this work, hyperspectral quantum emitter localization microscopy is used to locate 33 SPEs in nanoparticle-strained WSe
monolayers with sub-diffraction-limit resolution (≈30 nm) and correlate their positions with the underlying strain field via image registration. In this system, spectrally pure emitters are not concentrated at the highest strain location due to spectral contamination; instead, isolable SPEs are distributed away from points of peak strain with an average displacement of 240 nm. These observations point toward a need for a change in the design rules for strain-engineered SPEs and constitute a key step toward realizing next-generation quantum optical architectures.
Strain‐engineering in atomically thin metal dichalcogenides is a useful method for realizing single‐photon emitters (SPEs) for quantum technologies. Correlating SPE position with local strain ...topography is challenging due to localization inaccuracies from the diffraction limit. Currently, SPEs are assumed to be positioned at the highest strained location and are typically identified by randomly screening narrow‐linewidth emitters, of which only a few are spectrally pure. In this work, hyperspectral quantum emitter localization microscopy is used to locate 33 SPEs in nanoparticle‐strained WSe2 monolayers with sub‐diffraction‐limit resolution (≈30 nm) and correlate their positions with the underlying strain field via image registration. In this system, spectrally pure emitters are not concentrated at the highest strain location due to spectral contamination; instead, isolable SPEs are distributed away from points of peak strain with an average displacement of 240 nm. These observations point toward a need for a change in the design rules for strain‐engineered SPEs and constitute a key step toward realizing next‐generation quantum optical architectures.
The positions of spectrally pure quantum emitters in nanoparticle‐strained WSe2 monolayers are mapped to the underlying strain field with a resolution below the diffraction limit (≈30 nm). The quantum emitters are displaced from the local strain maxima by an average distance of 240 nm, which contradicts the assumption that strain‐induced quantum emitters are concentrated at the local strain maxima.
Ever since the first atomic structure of an enzyme was solved, the discovery of the mechanism and dynamics of reactions catalyzed by biomolecules has been the key goal for the understanding of the ...molecular processes that drive life on earth. Despite a large number of successful methods for trapping reaction intermediates, the direct observation of an ongoing reaction has been possible only in rare and exceptional cases.
Here, we demonstrate a general method for capturing enzyme catalysis "in action" by mix-and-inject serial crystallography (MISC). Specifically, we follow the catalytic reaction of the Mycobacterium tuberculosis β-lactamase with the third-generation antibiotic ceftriaxone by time-resolved serial femtosecond crystallography. The results reveal, in near atomic detail, antibiotic cleavage and inactivation from 30 ms to 2 s.
MISC is a versatile and generally applicable method to investigate reactions of biological macromolecules, some of which are of immense biological significance and might be, in addition, important targets for structure-based drug design. With megahertz X-ray pulse rates expected at the Linac Coherent Light Source II and the European X-ray free-electron laser, multiple, finely spaced time delays can be collected rapidly, allowing a comprehensive description of biomolecular reactions in terms of structure and kinetics from the same set of X-ray data.
In this study, a current source nine-switch ac/ac converter for microgrid application is presented. In contrast to traditional back-to-back configuration, the number of switching devices in the ...proposed converter decreases from 12 to 9 with three insulated gate bipolar transistors and three diodes reduced, which achieves simpler structure and lower cost on switching devices. In addition, in comparison with its voltage source counterparts, the proposed converter inherits the advantages of sinusoidal output voltage and current waveform and no use of dc-link electrolytic capacitor. Moreover, a model predictive control (MPC) without weighting factor selection issue is designed for the proposed converter to realise both sides’ power flow regulation. Simulation and experiments have been conducted, which validate the effectiveness of the proposed converter and MPC scheme.
PurposeThe paper aims to investigate how a tablet's design features, namely, its navigation design and visual appearance, influence users' enjoyment, concentration and control, when using tablets for ...problem-solving, and thereafter how their core flow experiences impact their perceived performance and efficiency with problem-solving.Design/methodology/approachThis study uses a field survey approach to engage 87 participants in a decision sciences class to use eTextbooks and a few other associated educational apps including CourseSmart app for e-notes and highlighting, sketchbook app and a calculator app in tablets to resolve class problems at a large US university.FindingsThis study finds that the tablet's interface design features (navigation and visual appearance) make users engrossed in their problem-solving processes with perceived enjoyment, concentration and control. This, in turn, impacts their perceived performance and efficiency. Moreover, visual appearance plays the most significant role in arousing users' affective emotions (i.e. enjoyment), while interface navigation is crucial to engage users' deep concentration (i.e. cognition) and control for problem-solving.Practical implicationsModern tablets are being used widely in various sectors. More in-depth user flow experience design associated with tablet use for problem-solving contexts should be further advocated in order to provide more engaging and meaningful flow experiences to users.Originality/valueThis study shows that the design of the tablet interface can engage users in problem-solving processes in both affective and cognitive ways. It provides valuable insights on tablet interface design for problem-solving.
Patients with Klippel-Feil syndrome may present with neurologic complaints such as neck pain, radiculopathy and gait instability. Here we describe surgical management of a patient with congenital ...fusion of the occipital-cervical region and also block circumferential fusion of dens to T3 with spinal cord compression. This report is the first of its kind with such extensive fusion.
Our patient was a 56 year-old female, who presented with neck pain and tingling in all extremities. On exam, she had a short neck, prominent jaw with extremely limited range of motion in neck and features of myelopathy. CT showed fusion of the dens to T3 vertebrae. Patient underwent sub-occipital craniectomy, C1 laminectomy and Occiput to T5 posterior fixation and fusion with neurologic improvement.
This is the first reported case of Klippel-Feil syndrome with fusion of all cervical vertebrae down to T3. We recommend surgery for advanced cases of myelopathy or radiculopathy due to stenosis and spinal instability.
Percutaneous approaches to the spine have been explored recently for various procedures, including transforaminal lumbar interbody fusion. It is known that facet decortication leads to higher rates ...of fusion, but effective percutaneous approaches have not been well documented. There are a set of instruments used in the cervical spine for percutaneous decortication, the CORUS™ Spinal System-X (DI# 00852776006508), which may be useful in this setting. Our aim was to investigate the feasibility of decorticating the lumbar facet joints with these instruments in cadavers to aid in minimally invasive lumbar fusion.
We performed percutaneous facet joint decortication at each facet joint in the lumbar spine in two adult cadavers. We tested varying degrees of laterality for entry points and angulation for access at each level to optimize the innovative procedure.
When using the CORUS™ Spinal System-X to obtain percutaneous access for facet decortication in the lumbar spine, we successfully dissected down to the facet joint without neurovascular injury. At the L1-L2 and L2-L3 levels, access was best obtained at 4 cm from midline with an angulation of 10°. At the L3-L4 and L4-L5 level, access was best obtained at 4 cm from midline with an angulation of 20°.
This study demonstrates that percutaneous lumbar facet joint decortication is feasible with the CORUS™ Spinal System-X instruments, and warrants further, comparative study in the clinical setting
We highlight the use of multimodal imaging to diagnose and report what is, to our knowledge, a novel presentation of bilateral choroidal neovascularization (CNV) and prominent macular choroidal folds ...(CFs) in a patient with pattern dystrophy. An 81-year-old Caucasian male presented with painless, blurry central vision in both eyes. Color fundus photography, spectral-domain optical coherence tomography (SD-OCT), fluorescein angiography (FA), fundus autofluorescence, and brightness scan ultrasonography supported the diagnosis of pattern dystrophy with bilateral CNV and CF. In the right eye, visually significant CNV worsened post-bevacizumab treatment but responded well to aflibercept. During 4-year follow-up, Snellen visual acuity remained excellent in both eyes at 20/20, including the treatment-naïve left eye. CFs remained markedly stable in both eyes.
B.J. Fogg's Functional Triad shows the manner in which computing technologies can persuade people by playing 3 different functional roles, namely, as tools, media, or social actors. However, the ...effects of user perceptions of these 3 functional roles are largely unknown. We advance Fogg's framework by developing a conceptual model to explain how a feature of a computing technology (ie, the trade‐off transparency feature of a recommendation agent RA, which interactively demonstrates the trade‐offs among product attribute values) can result in certain outcomes by shaping the beliefs of individuals regarding the 3 functional roles. We examine the effects of the perceived Functional Triad on the following 3 outcomes: (1) persuading users to use an RA (intention to use), (2) persuading users to follow the advice of the RA (recommendation adherence), and (3) persuading users to recommend the RA to others (recommendation to friends). We conducted a laboratory experiment to manipulate 4 levels of trade‐off transparency, thereby creating an adequate amount of variations for the perceived Functional Triad. A total of 160 participants were recruited from a large university in North America. Although designers could control the technology design aspects, these designs may not accomplish the intended effects on users, who have their own perceptions. This study contributes to existing literature by simultaneously evaluating the 3 different outcomes of the Functional Triad from the perspective of users.
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