The ability of light to carry and deliver orbital angular momentum (OAM) in the form of optical vortices has attracted much interest. The physical properties of light with a helical wavefront can be ...confined onto two-dimensional surfaces with subwavelength dimensions in the form of plasmonic vortices, opening avenues for thus far unknown light-matter interactions. Because of their extreme rotational velocity, the ultrafast dynamics of such vortices remained unexplored. Here we show the detailed spatiotemporal evolution of nanovortices using time-resolved two-photon photoemission electron microscopy. We observe both long- and short-range plasmonic vortices confined to deep subwavelength dimensions on the scale of 100 nanometers with nanometer spatial resolution and subfemtosecond time-step resolution. Finally, by measuring the angular velocity of the vortex, we directly extract the OAM magnitude of light.
Transformation of light carrying spin angular momentum (SAM) to optical field vortices carrying orbital angular momentum (OAM) has been of wide interest in recent years. The interactions between two ...optical fields, each carrying one of those degrees of freedom, and furthermore, the transfer of the resulting angular momentum product to matter are seldom discussed. Here, we measure the interaction between 3D light carrying axial SAM and 2D plasmon-polariton vortices carrying high-order transverse OAM. The interaction is mediated by two-photon absorption within a gold surface, imprinting the resulting angular-momentum mixing into matter by excitation of electrons that are photo-emitted into vacuum. Interestingly, the spatial distribution of the emitted electrons carries the signature of a subtraction of the spin from the orbit angular momenta. We show experimentally and theoretically that the absorptive nature of this interaction leads to both single and double photon-plasmon angular momentum mixing processes by one- and two- photon interactions. Our results demonstrate high order angular momenta light-matter interactions, provide a glimpse into specific electronic excitation routes, and may be applied in future electronic sources and coherent control.
Visible wavelengths of light control the quantum matter of atoms and
molecules and are foundational for quantum technologies, including
computers, sensors, and clocks. The development of visible ...integrated
photonics opens the possibility for scalable circuits with complex
functionalities, advancing both science and technology frontiers. We
experimentally demonstrate an inverse design approach based on the
superposition of guided mode sources, allowing the generation and
complete control of free-space radiation directly from within a single
150 nm layer , showing low loss across visible and
near-infrared spectra. We generate diverging circularly polarized
beams at the challenging 461 nm wavelength that can be directly used
for magneto-optical traps of strontium atoms, constituting a
fundamental building block for a range of atomic-physics-based quantum
technologies. Our generated topological vortex beams and the potential
for spatially varying polarization emitters could open unexplored
light–matter interaction pathways, enabling a broad new
photonic–atomic paradigm. Our platform highlights the generalizability
of nanoscale devices for visible-laser emission and will be critical
for scaling quantum technologies.
Cyclo-oxygenase (COX) 1 mediates the production of thromboxane A2 in platelets, leading to platelet aggregation and vasoconstriction. Conversely, COX2 catalyzes endothelial prostacyclin synthesis, ...which effectively counteracts thromboxane A2, triggering vasodilation and platelet inhibition. Selective COX2 inhibitors decrease prostacyclin production, potentially disrupting homeostasis and creating a prothrombotic state. The VIGOR study findings of increased cardiovascular risk with rofecoxib were subsequently confirmed by large meta-analyses, observational studies and recent APPROVe trial publication. The APC trial findings of increased cardiovascular risk with Celebrex (celecoxib) conflict with those in the ADAPT trial, the upcoming PreSAP publication, a case-control study by Graham et al. and prior large clinical trials, meta-analyses and observational studies of this drug. Therefore, while an adverse class effect is a possibility for COX2 inhibitors, the published data are inconsistent. Baseline cardiovascular risk in patients might contribute significantly to these findings. In light of the negative Vioxx (rofecoxib) publicity, however, COX2 inhibitors might forever remain underinvestigated. The relative selectivity of these compounds for COX2 is extremely variable, casting significant doubt on the class-effect hypothesis. Improved endothelial function has also been reported with celecoxib, leading to endothelium-dependent vasodilation, and associated decreases in C-reactive protein and LDL cholesterol. The addition of meloxicam to low-dose aspirin and heparin has improved clinical outcomes after acute coronary syndromes. These are the first studies suggesting improvement in endothelial function and reduction of inflammation with COX2 inhibition. Thus, more randomized controlled trials are needed to study the relative cardiovascular effects of different COX2 inhibitors, alone and in combination with aspirin.
The authors investigated whether practice (or graded) quizzes, with or without provision of correct answers, would be more beneficial for introductory psychology exam performance. In six sections (N ...= 249) of an introductory psychology class, taught by the same professor, different approaches to quizzes were applied across sections to measure effect on exam performance. Findings showed that compared to other conditions, students performed significantly better on exams with practice rather than graded quizzes but only when correct answers to the quizzes were provided. It may be that practice quizzes help facilitate students' intrinsic motivation.
Developmentally regulated endothelial locus-1 (Del-1) is an extracellular matrix protein that is expressed by endothelial cells during embryological vascular development. We speculated that Del-1 may ...be reexpressed in ischemia and may be involved in endogenous angiogenesis.
Del-1 protein was detected by immunohistochemistry in murine ischemic hindlimb after femoral artery excision. To determine whether exogenous Del-1 would augment angiogenesis in vivo, Del-1 or vehicle was administered for 3 weeks by intramuscular injection of murine ischemic hindlimbs. Angiogenesis was quantified by gadolinium-MRI perfusion and capillary densitometry. We used a disc angiogenesis system (DAS) to characterize the angiogenic response to vehicle (PBS), Del-1, Del-1 mutant (altered RGD domain), Del-1 minor (truncated discoidin-I-like domain), or basic fibroblast growth factor. After 14 days, the discs were extracted and sectioned to quantify vascular growth by morphometry. Endogenous Del-1 protein expression was increased in ischemic hindlimbs. Administration of Del-1 increased hindlimb vascular flow index and capillary density. In the DAS, Del-1 doubled fibrovascular growth, as did basic fibroblast growth factor. However, angiogenesis was not enhanced by the Del-1 mutant or Del-1 minor proteins.
Del-1 is expressed in ischemic tissue. Del-1 stimulates angiogenesis, an effect that is dependent on the RGD motif and a second signaling sequence in the discoidin-I-like domain. Exogenous intramuscular administration of Del-1 significantly enhances angiogenesis in the murine ischemic hindlimb. Del-1 may prove to be a novel therapeutic agent for patients with ischemia.
The supervisory working alliance is an important outcome for supervision success (Ladany, Ellis, & Friedlander, 1999), and it has been proposed that the alliance is influenced by interpersonal, ...affective, and cultural supervisee characteristics (Bennett, Mohr, Deal, & Hwang, 2013; Bhat & Davis, 2007; Dickson, Moberly, Marshall, & Reilly, 2011). To that effect, the aim of the present study was to examine a proposed model of relationships between trainee ratings of the supervisory working alliance, trainee willingness to disclose in supervision, supervisee shame-proneness, and interdependent self-construal using structural equation modeling. A sample of 201 counselors-in- training participated in the study, and results suggested that the target model exhibited good fit to the data. An alternate model of relationships was also examined and similarly evidenced good fit to the data but did not significantly improve model fit. The following hypothesized relationships were supported: 1) higher interdependent self-construal predicted greater shame-proneness for trainees and 2) greater willingness to disclose in supervision predicted higher ratings of the supervisory working alliance. However, shame-proneness was not a significant predictor of trainee disclosure or of the supervisory working alliance, and trainee willingness to disclose was not found to mediate the relationship between shame-proneness and the supervisory working alliance. Implications, limitations, and future directions are discussed.
One theory explains the consistent negative stereotype toward stutterers by suggesting that it is formed by a process of inference. Fluent speakers use their own experiences of normal dysfluency to ...infer the personality of persons who are often dysfluent: stutterers. This was examined by analyzing the relationships between 164 adolescents' attitudes toward their own communication, measured by the Erickson Scale, & their attitudes toward stuttering adolescents. Attitudes toward stutterers were measured by a semantic differential questionnaire with 25 bipolar adjective scales divided into the Tenseness & Pleasantness Scale. The effect of stutterers' sex & participants' sex was examined as well. The results showed a weak positive correlation between boys' attitudes toward their own communication & their attitudes toward male stutterers on the Tenseness Scale only. These results only partially supported the inference theory. In addition, the sex of the persons who stutter had no effect on the attitudes expressed toward them, showing that female stutterers did not have a double minority status. On the other hand, female participants showed significantly more positive attitudes toward stutterers on the Pleasantness Scale of the semantic differential questionnaire. Finally, a positive correlation was found between attitudes toward own communication & social self-image, emphasizing the importance of communication skills for social adjustment. 3 Tables, 46 References. Adapted from the source document
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