Effect of two-photon absorption on trapping of plasmonic nanoparticles.

In this paper, we introduce a theoretical framework for optical trapping that integrates nonlinear polarization within the dipole approximation. This theory represents the most comprehensive analytic model to date capable of resolving the discrepancies between the observed and simulated trapping of plasmonic nanoparticles. Our theory elucidates how two-photon absorption can account for the stable trapping of gold nanoparticles, including their longitudinal stability, especially near their plasmon resonance.

DNA-PK is activated by SIRT2 deacetylation to promote DNA double-strand break repair by non-homologous end joining.

DNA-dependent protein kinase (DNA-PK) plays a critical role in non-homologous end joining (NHEJ), the predominant pathway that repairs DNA double-strand breaks (DSB) in response to ionizing radiation (IR) to govern genome integrity. The interaction of the catalytic subunit of DNA-PK (DNA-PKcs) with the Ku70/Ku80 heterodimer on DSBs leads to DNA-PK activation; however, it is not known if upstream signaling events govern this activation. Here, we reveal a regulatory step governing DNA-PK activation by SIRT2 deacetylation, which facilitates DNA-PKcs localization to DSBs and interaction with Ku, thereby promoting DSB repair by NHEJ.

Fostering diversity and a culture of inclusion in clinical research by training and hiring community members as clinical research assistants.

The University of Pittsburgh (Pitt) Clinical and Translational Science Institute (CTSI) and the nonprofit Bidwell Training Center co-developed a new program for translational workforce diversification and development to foster diversity and inclusion in clinical research. The STricklAnd Research Training (START) program provides students in the Medical Assistant program at Bidwell a career path in clinical research. We created a 12-hour didactic package that covers responsible conduct of human subjects research and good clinical practice as an add-on to existing vocational curriculums.

Body-of-revolution finite-difference time-domain modeling of hybrid-plasmonic ring resonators.

Development of a computational technique for the analysis of quasi-normal modes in hybrid-plasmonic resonators is the main goal of this research. Because of the significant computational costs of this analysis, one has to take various symmetries of these resonators into account. In this research, we consider cylindrical symmetry of hybrid-plasmonic ring resonators and implement a body-of-revolution finite-difference time-domain (BOR-FDTD) technique to analyze these resonators.

Hybrid acousto-optic/electro-optic leaky-mode deflectors.

We introduce a solution for enabling vertical parallax in solid-state leaky mode devices by integrating an electro-optic (EO) phased array. We present a simple proof of concept for an acousto-optic (AO)/EO modulator deflecting in two axes and describe how this could be refined and adapted for transparent large-format and near-eye holographic displays.

Fabrication and Testing of Miniature Automatic Photophoretic Trapping Rigs.

This paper presents an automated, rapid-fab-compatible, photophoretic trap test rig to enable the democratization and crowdsourcing of volumetric display research. The rig can be constructed within 2 h using a laser cutter, 3-dimensional (3D) printer, and common hand tools. In its current form, the rig can be used to test the following critical parameters: particle type, trap type, numerical aperture, and airflow at a rate of approximately 250 samples per hour.

Photophoretic trap testing rig for volumetric displays.

In this Note, we describe a test rig for optimizing the trapping parameters of optical trap displays. This rig allows targeted experimentation on software, hardware, and environmental variables. These variables affect the success and robustness of particle trapping.

Simulating virtual images in optical trap displays.

Optical trap displays (OTD) are an emerging display technology with the ability to create full-color images in air. Like all volumetric displays, OTDs lack the ability to show virtual images. However, in this paper we show that it is possible to instead simulate virtual images by employing a time-varying perspective projection backdrop.

Elongated neutrophil-derived structures are blood-borne microparticles formed by rolling neutrophils during sepsis.

Rolling neutrophils form tethers with submicron diameters. Here, we report that these tethers detach, forming elongated neutrophil-derived structures (ENDS) in the vessel lumen. We studied ENDS formation in mice and humans in vitro and in vivo.

Impact of Pool Testing in Detection of Asymptomatic Patients with COVID-19.

Objective: During the current pandemic, COVID-19 has been detected in patients using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) that confirms the presence of SARS-CoV-2 RNA. The demand for increased testing, particularly for asymptomatic individuals required alternative approaches to single-patient RT-PCR testing, such as pooling.

Methods: This study explored the impact of dilution on the detectability of SARS-CoV-2 in asymptomatic patients using RT-PCR and demonstrated that pooling can be effective in low prevalence populations.

One-pot synthesis of heterodimeric agonists that activate the canonical Wnt signaling pathway.

Fragment antigen-binding domains (Fabs) from anti-Frizzled and anti-LRP6 monoclonal antibodies were conjugated using SpyTag-SpyCatcher chemistry via a one-pot reaction. The resulting synthetic heterodimeric agonist outperformed the natural ligand, Wnt-3a, in activating canonical Wnt signaling in mammalian cells. This approach should be broadly applicable to activate receptor-mediated cellular signaling.

Improving photophoretic trap volumetric displays [Invited].

Since the introduction of optical trap displays in 2018, there has been significant interest in further developing this technology. In an effort to channel interest in the most productive directions, this work seeks to illuminate those areas that, in the authors' opinion, are most critical to the ultimate success of optical trap displays as a platform for aerial 3D imaging. These areas include trapping, scanning, scaling, robustness, safety, and occlusion.

Reversing the thermal equilibration by differential magneto-thermal force.

A special magnetic body force, the differential magneto-thermal (DMT) force, was proposed to reverse thermal equilibration by 'pushing' a fluid element colder than its surroundings to a colder region, and a fluid element hotter than its surroundings to a hotter region [1]. In this work, we discuss the fulfilment of the requirements for this force and the experiment to verify it. We present experimental and analytical results that clearly demonstrate: (1) approaching thermal equilibrium in our magnetic fluid sample was indeed 'reversed' as the magnetic body force introduces the localized flows that stop the conventional convective heat transfer; (2) the DMT force density calculated with experimental parameters agrees with the design principle.

Microplate-based surface area assay for rapid phenotypic antibiotic susceptibility testing.

Rapid delivery of proper antibiotic therapies to infectious disease patients is essential for improving patient outcomes, decreasing hospital lengths-of-stay, and combating the antibiotic resistance epidemic. Antibiotic stewardship programs are designed to address these issues by coordinating hospital efforts to rapidly deliver the most effective antibiotics for each patient, which requires bacterial identification and antimicrobial susceptibility testing (AST). Despite the clinical need for fast susceptibility testing over a wide range of antibiotics, conventional phenotypic AST requires overnight incubations, and new rapid phenotypic AST platforms restrict the number of antibiotics tested for each patient.

Hardware and software improvements to a low-cost horizontal parallax holographic video monitor: publisher's note.

This publisher's note corrects a trademark concern in Appl. Opt.57, A122 (2018)APOPAI0003-693510.

Both positional and chemical variables control proteolytic cleavage of a presenilin ortholog.

Mechanistic details of intramembrane aspartyl protease (IAP) chemistry, which is central to many biological and pathogenic processes, remain largely obscure. Here, we investigated the kinetics of a microbial intramembrane aspartyl protease (mIAP) fortuitously acting on the renin substrate angiotensinogen and the C-terminal transmembrane segment of amyloid precursor protein (C100), which is cleaved by the presenilin subunit of γ-secretase, an Alzheimer disease (AD)-associated IAP. mIAP variants with substitutions in active-site and putative substrate-gating residues generally exhibit impaired, but not abolished, activity toward angiotensinogen and retain the predominant cleavage site (His-Thr).

A photophoretic-trap volumetric display.

Free-space volumetric displays, or displays that create luminous image points in space, are the technology that most closely resembles the three-dimensional displays of popular fiction. Such displays are capable of producing images in 'thin air' that are visible from almost any direction and are not subject to clipping. Clipping restricts the utility of all three-dimensional displays that modulate light at a two-dimensional surface with an edge boundary; these include holographic displays, nanophotonic arrays, plasmonic displays, lenticular or lenslet displays and all technologies in which the light scattering surface and the image point are physically separate.

Performance of candidates disclosing dyslexia with other candidates in a UK medical licensing examination: cross-sectional study.

Purpose Of The Study: The aim of this study was to compare performance of candidates who declared an expert-confirmed diagnosis of dyslexia with all other candidates in the Applied Knowledge Test (AKT) of the Membership of the Royal College of General Practitioners licensing examination.

Study Design: We used routinely collected data from candidates who took the AKT on one or more occasions between 2010 and 2015. Multivariate logistic regression was used to analyse performance of candidates who declared dyslexia with all other candidates, adjusting for candidate characteristics known to be associated with examination success including age, sex, ethnicity, country of primary medical qualification, stage of training, number of attempts and time spent completing the test.

Hardware and software improvements to a low-cost horizontal parallax holographic video monitor.

Displays capable of true holographic video have been prohibitively expensive and difficult to build. With this paper, we present a suite of modularized hardware components and software tools needed to build a HoloMonitor with basic "hacker-space" equipment, highlighting improvements that have enabled the total materials cost to fall to $820, well below that of other holographic displays. It is our hope that the current level of simplicity, development, design flexibility, and documentation will enable the lay engineer, programmer, and scientist to relatively easily replicate, modify, and build upon our designs, bringing true holographic video to the masses.

Microparticle-mediated sequestration of cell-secreted proteins to modulate chondrocytic differentiation.

Unlabelled: Protein delivery is often used in tissue engineering applications to control differentiation processes, but is limited by protein instability and cost. An alternative approach is to control the cellular microenvironment through biomaterial-mediated sequestration of cell-secreted proteins important to differentiation. Thus, we utilized heparin-based microparticles to modulate cellular differentiation via protein sequestration in an in vitro model system of endochondral ossification.

Backside emission leaky-mode modulators.

We report on an advancement to leaky-mode modulators that allows for backside emission from the device. This is accomplished by adding a high spatial frequency surface relief grating (~300 nm period) to the backside of the modulator. The outcome being a theoretical arbitrary increase in usable output aperture, at the cost of angular deflection.

Paired leaky mode spatial light modulators with a 28° total deflection angle.

In this Letter, we present a paired set of waveguide spatial light modulators (SLMs) capable of a maximum light deflection nearing 28° for red. This deflection, which is several times larger than the angular sweep of current, state-of-the-art modulators, is made possible by the unilateral, near-collinear waveguide nature of the leaky mode interaction. The ability to double angular output in this way, which is either not possible or not practical in other SLMs, is possible in leaky mode devices, thanks to the absence of zero-order light and the lack of high-order outputs.

Isomeric Character of the Lowest Observed 4^{+} State in ^{44}S.

Previous experiments observed a 4^{+} state in the N=28 nucleus ^{44}S and suggested that this state may exhibit a hindered E2-decay rate, inconsistent with being a member of the collective ground state band. We populate this state via two-proton knockout from a beam of exotic ^{46}Ar projectiles and measure its lifetime using the recoil distance method with the GRETINA γ-ray spectrometer. The result, 76(14)_{stat}(20)_{syst}  ps, implies a hindered transition of B(E2;4^{+}→2_{1}^{+})=0.

Leaky-mode waveguide modulators with high deflection angle for use in holographic video displays.

Film display holograms typically diffract light over a wide enough view-angle to be viewed, directly, without intervening optics. However, all holographic video displays (with the exception of eye-tracked systems) must use optics beyond the hologram surface to overcome the challenges of small display extent and low diffraction angle by using some form of demagnification and derotation (i.e.