Publications by authors named "Chanana A"

The size of the bandgap in a photonic crystal ring is typically intuitively considered to monotonically grow as the modulation amplitude of the grating increases, causing increasingly large frequency splittings between the "dielectric" and "air" bands. In contrast, here we report that as the modulation amplitude in a photonic crystal ring increases, the bandgap does not simply increase monotonically. Instead, after the initial increase, the bandgap closes and then reopens again with the two bands flipped in energy.

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In a popular integration process for quantum information technologies, localization microscopy of quantum emitters guides lithographic placement of photonic structures. However, a complex coupling of microscopy and lithography errors degrades registration accuracy, severely limiting device performance and process yield. We introduce a methodology to solve this widespread but poorly understood problem.

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Background: The gut microbiota (GM) of the human body comprises several species of microorganisms. This microorganism plays a significant role in the physiological and pathophysiological processes of various human diseases.

Methods: The literature review includes studies that describe causative factors that influence GM.

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Article Synopsis
  • Micro-/nanocavities are crucial for enhancing light-matter interactions in cavity quantum electrodynamics (cQED), with whispering gallery mode (WGM) geometries offering ease of design but limited mode volume.
  • New photonic crystal ring (PhCR) designs, specifically "rod" and "slit" unit cells, maintain high quality factors and improve defect localization compared to traditional WGM structures.
  • The study highlights that these new PhCRs are easier to fabricate and provide a promising platform for further exploration in cQED applications.
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Frequency engineering of whispering-gallery resonances is essential in microcavity nonlinear optics. The key is to control the frequencies of the cavity modes involved in the underlying nonlinear optical process to satisfy its energy conservation criterion. Compared to the conventional method that tailors dispersion by cross-sectional geometry, thereby impacting all cavity mode frequencies, grating-assisted microring cavities, often termed as photonic crystal microrings, provide more enabling capabilities through mode-selective frequency control.

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The scaling of many photonic quantum information processing systems is ultimately limited by the flux of quantum light throughout an integrated photonic circuit. Source brightness and waveguide loss set basic limits on the on-chip photon flux. While substantial progress has been made, separately, towards ultra-low loss chip-scale photonic circuits and high brightness single-photon sources, integration of these technologies has remained elusive.

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Continuous wave optical parametric oscillation (OPO) provides a flexible approach for accessing mid-infrared wavelengths between 2 µm and 5 µm, but operation at these wavelengths has not yet been integrated into silicon nanophotonics. Typically, a Kerr OPO uses a single transverse mode family for pump, signal, and idler modes, and relies on a delicate balance to achieve normal (but close-to-zero) dispersion near the pump and the requisite higher-order dispersion needed for phase- and frequency-matching. Within integrated photonics platforms, this approach results in two major problems.

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Utilizing the spin degree of freedom of photoexcitations in hybrid organic inorganic perovskites for quantum information science applications has been recently proposed and explored. However, it is still unclear whether the stable photoexcitations in these compounds correspond to excitons, free/trapped electron-hole pairs, or charged exciton complexes such as trions. Here we investigate quantum beating oscillations in the picosecond time-resolved circularly polarized photoinduced reflection of single crystal methyl-ammonium tri-iodine perovskite (MAPbI) measured at cryogenic temperatures.

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Objectives: While high-risk HPV (hrHPV) testing is not formally recommended as a surveillance modality in patients with a history of cervical cancer, it is often performed in routine practice. It is unclear whether the presence of hrHPV infection after cervical cancer treatment is associated with recurrent disease.

Methods: Patients with a cervical cancer diagnosis who were seen in a single institution between May 2012 and December 2019 were retrospectively identified.

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Article Synopsis
  • The omentum, a part of the body where ovarian cancer often spreads, has immune cell groups called milky spots, but their role in cancer metastasis is unclear.
  • Researchers discovered that omental macrophages (a type of immune cell) help ovarian cancer cells move and settle in the omentum by releasing specific chemokines that interact with CCR1 receptors.
  • Reducing or blocking the function of these macrophages and their signaling pathways significantly decreased the spread of ovarian cancer in the omentum, highlighting the importance of omental macrophages in cancer migration.
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The two-dimensional (2D) Ruddlesden-Popper organic-inorganic halide perovskites such as (2D)-phenethylammonium lead iodide (2D-PEPI) have layered structure that resembles multiple quantum wells (MQW). The heavy atoms in 2D-PEPI contribute a large spin-orbit coupling that influences the electronic band structure. Upon breaking the inversion symmetry, a spin splitting ('Rashba splitting') occurs in the electronic bands.

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Using first-principles density functional theoretical analysis, we predict coexisting ferroelectric and semimetallic states in a two-dimensional monolayer of h-NbN subjected to an electric field and in-plane strain (ε). At strains close to ε=4.85%, where its out-of-plane spontaneous polarization changes sign without inverting the structure, we demonstrate a hysteretic response of its structure and polarization to an electric field, and uncover a three-state (P=±P_{o}, 0) switching during which h-NbN passes through Dirac semimetallic states.

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Article Synopsis
  • * The study focuses on "magnetic" organic light-emitting diodes using ferromagnetic electrodes (like Co and NiFe), revealing that the magnetic field strength directly influences the fringe field in the organic layer.
  • * Two types of fringe fields are observed in the NiFe film when exposed to an out-of-plane magnetic field: one remains constant regardless of distance and another that decreases with distance, indicating a complex interaction within the materials used.
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Three-dimensional (3D) semimetals have been predicted and demonstrated to have a wide variety of interesting properties associated with their linear energy dispersion. In analogy to two-dimensional (2D) Dirac semimetals, such as graphene, CdAs has shown ultrahigh mobility and large Fermi velocity and has been hypothesized to support plasmons at terahertz frequencies. In this work, we experimentally demonstrate synthesis of high-quality large-area CdAs thin films through thermal evaporation as well as the experimental realization of plasmonic structures consisting of periodic arrays of CdAs stripes.

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Purpose Of Review: To provide an update on cell-based immunotherapies in solid tumors particularly in gynecological cancers.

Recent Findings: Improvements have been made in engineering T cells to overcome the immunosuppressive environment in ovarian cancer. Significant efforts are underway to create 'off the shelf' cell therapies which leverage natural killer (NK) cells and would not rely on engineering a patient's T cells.

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Article Synopsis
  • The research focuses on developing ultrafast, frequency-agile terahertz metamaterials using multiple perovskites, enabling advanced applications in spectroscopy and communications.
  • A unique fabrication technique protects previously deposited perovskites from solvents, allowing for precise micrometer-scale patterning and proximity of different perovskites within a unit cell.
  • The ability to tune terahertz resonances based on varying optical pump fluences and wavelengths leads to new functionalities, including resonance tuning and suppression, paving the way for innovative terahertz device capabilities.
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We report on terahertz characterization of La-doped BaSnO (BSO) thin-films. BSO is a transparent complex oxide material, which has attracted substantial interest due to its large electrical conductivity and wide bandgap. The complex refractive index of these films is extracted in the 0.

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Controlling and modulating terahertz signals is of fundamental importance to allow systems level applications. We demonstrate an innovative approach for controlling the propagation properties of terahertz (THz) radiation, through use of both the excitation optical wavelength (colour) and intensity. We accomplish this using two-dimensional (2D) layered hybrid trihalide perovskites that are deposited onto silicon substrates.

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Background: Aberrant hedgehog signalling underlies the development of basal-cell carcinomas. We previously reported the interim analysis of a multicentre, randomised, double-blind, placebo-controlled, phase 2 trial in patients with the basal-cell nevus (Gorlin) syndrome indicating that the smoothened inhibitor vismodegib reduces basal-cell carcinoma tumour burden and prevents new basal-cell carcinoma growth in patients with basal-cell nevus syndrome. We report the final results of this 36 month trial.

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Purpose Of Review: The article provides an overview of advances in the induced pluripotent stem cell field to model cardiomyopathies of inherited inborn errors of metabolism and acquired metabolic syndromes in vitro.

Recent Findings: Several inborn errors of metabolism have been studied using 'disease in a dish' models, including Pompe disease, Danon disease, Fabry disease, and Barth syndrome. Disease phenotypes of complex metabolic syndromes, such as diabetes mellitus and aldehyde dehydrogenase 2 deficiency, have also been observed.

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Boiling, a dynamic and multiscale process, has been studied for several decades; however, a comprehensive understanding of the process is still lacking. The bubble ebullition cycle, which occurs over millisecond time-span, makes it extremely challenging to study near-surface interfacial characteristics of a single bubble. Here, we create a steady-state vapor bubble that can remain stable for hours in a pool of sub-cooled water using a femtosecond laser source.

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Importance: Keratocystic odontogenic tumors (KCOTs) of the jaw affect more than 65% of patients with basal cell nevus syndrome (BCNS). Surgery frequently causes facial disfigurement and is not always curative. Most BCNS-related and some sporadic KCOTs have malignant activation of the Hedgehog signaling pathway.

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Sporadic human basal cell carcinomas (BCC) are generally well managed with current surgical modalities. However, in the subset of high-risk patients predisposed to developing large numbers of BCCs, there is an unmet need for effective, low-morbidity chemoprevention. This population includes fair-skinned patients with extensive sun exposure and those with genodermatoses such as the basal cell nevus (Gorlin) syndrome (BCNS).

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