Small Disk Research Articles

TMOD-09. NEWLY DESIGNED TUMOR TREATING FIELDS (TTFIELDS) ARRAYS FOR THE MOUSE HEAD DEMONSTRATE EFFICACY FOR TREATMENT OF GLIOBLASTOMA

Abstract Tumor Treating Fields (TTFields) therapy is a cancer treatment modality based on continuous, non-invasive delivery of electric fields. TTFields therapy is approved for treatment of glioblastoma (GBM), delivered to the patient’s brain by two array pairs placed on the scalp. Further research in animals to expand the knowledge regarding TTFields treatment of GBM is limited, as this is mainly performed in mouse models and arrays for application of TTFields to the mouse head are lacking. The small dimensions and specific geometries of the mouse head make the development of such arrays challenging. The aim of this study was to design arrays that will allow efficient and stable delivery of TTFields to the mouse head. To overcome the small head size, we developed a layout with two arrays situated on the head of the mouse, each divided into two smaller disks, and positioned opposite two arrays on the torso. We identified a thin and transparent adhesive tape (facilitating correct array positioning) with good tackiness and easy removal (without leaving residual adhesive on the skin). The arrays met the minimum treatment requirements: current ≥ 50 mA, usage ≥ 75%, field intensity ≥ 1 V/cm RMS. We then conducted an efficacy study with the new arrays, using GL-261 GBM cells intracranially injected into C57BL/6 mice. Treatment with sham-heat (control) or TTFields was initiated 11 days following tumor inoculation and maintained continuously for 12 days. Efficacy was measured via magnetic resonance imaging (MRI) of tumor volume, showing a decrease of 31% at treatment end in TTFields-treated mice versus the control. Overall, the new arrays are flexible, strongly adherent, deliver TTFields at a sufficient intensity, and showed efficacy for treating GBM in mice.

A small disc size, a big challenge: effect of optic disc size on the correlation between peripapillary choroidal thickness, peripapillary retinal nerve fiber layer, and ganglion cell layer.

We aimed to analyze the effect of optic disc size on the correlation between the peripapillary choroid (PPC), peripapillary retinal nerve fiber layer (RNFL), and macular ganglion cell inner plexiform layer (MGCIPL) thicknesses in subjects with ocular hypertension (OHT) and primary open angle glaucoma (POAG). This study included 61 eyes with a disc area (DA) of ≤ 1.63 mm2, 92 eyes with a DA of 1.63-2.42 mm2, and 59 eyes with a DA of ≥ 2.42 mm2 in small disc, regular disc, and large disc groups, respectively. The swept-source optical coherence tomography scans of the PPC, RNFL, and MGCIPL were analyzed according to disc size. The three groups did not significantly differ in RNFL or MGCIPL measurements, but the PPC measurement was statistically significantly higher in the small disc group and statistically significantly thinner in the large disc group. Most of the correlations observed between the RNFL and MGCIPL measurements and eye characteristics in the regular disc group were not detected in the small and large disc groups. While the RNFL and MGCIPL were well correlated in all disc size groups, the PPC did not correlate with the RNFL or MGCIPL in any of the groups. Overall, the RNFL and MGCIPL measurements were consistent across all three disc sizes. While the PPC was thicker in small discs than in larger discs, it was not correlated with the RNFL or MGCIPL.

Constraints on the accretion properties of quasi-periodic erupters from GRMHD simulations

Some apparently quiescent supermassive black holes (BHs) at centers of galaxies show quasi-periodic eruptions (QPEs) in the X-ray band, the nature of which is still unknown. A possible origin for the eruptions is an accretion disk. However, the properties of such disks are restricted by the timescales of recurrence and the duration of the flares. In this work, we test the possibility that the temporal properties of known QPEs can be explained by accretion from a compact accretion disk with an outer radius out g and we focus on a particular object, GSN 069. We ran several 3D general relativistic magnetohydrodynamic (GRMHD) simulations with the H-AMR code of thin and thick disks and studied how the initial disk parameters such as thickness, magnetic field configuration, magnetization, and Kerr parameter affect the observational properties of QPEs. We show that accretion onto a slowly rotating BH through a small, moderately thin accretion disk with an initially low plasma beta can explain the observed time between outbursts and the lack of evidence for a variable jet emission. In order to form such a disk, the accreting matter should have a low net angular momentum. A potential source for such low angular momentum matter with a quasi-periodic feeding mechanism might be a tight binary of wind-launching stars. Apart from their primary application, our results can also be useful for general studies of systems with small accretion disks, in which evolution occurs very rapidly so that the disks cannot be considered stationary. For such systems, it is important to understand how the initial conditions affect the results.

Electromagnetic signatures of black hole clusters in the center of super-Eddington galaxies

Supermassive black holes (SMBHs) at the centers of active galaxies are fed by accretion disks that radiate from the infrared or optical to the X-ray bands. Several types of objects can orbit SMBHs, including massive stars, neutron stars, clouds from the broad- and narrow-line regions, and X-ray binaries. Isolated black holes with a stellar origin (BHs of ∼10 M⊙) should also be present in large numbers within the central parsec of the galaxies. These BHs are expected to form a cluster around the SMBH as a result of the enhanced star formation rate in the inner galactic region and the BH migration caused by gravitational dynamical friction. However, except for occasional microlensing effects on background stars or gravitational waves from binary BH mergers, the presence of a BH population is hard to verify. In this paper, we explore the possibility of detecting electromagnetic signatures of a central cluster of BHs when the accretion rate onto the central SMBH is greater than the Eddington rate. In these supercritical systems, the accretion disk launches powerful winds that interact with the objects orbiting the SMBH. Isolated BHs can capture matter from this dense wind, leading to the formation of small accretion disks around them. If jets are produced in these single microquasars, they could be sites of particle acceleration to relativistic energies. These particles in turn are expected to cool by various radiative processes. Therefore, the wind of the SMBH might illuminate the BHs through the production of both thermal and nonthermal radiation.

A novel bionic constructional left atrial appendage occlude device: the result of preclinical experiment and first-in-human study

Abstract Objectives Left atrial appendage occlusion (LAAO) has emerged as a viable substitute for oral anticoagulation (OAC) for stroke prevention among individuals with atrial fibrillation (AF) these years. The high variability of left atrial appendage (LAA) in different individuals would lead to failure of LAAO or significant PDL post procedure using the existing occluders. Therefore, novel occluder which could address these issues is of great urgent. Methods SimuLock® occluders were implanted in 18 healthy canines percutaneously. Angiography and transesophageal echocardiography were employed to evaluate the effect of closure. The canines were sacrificed post-procedure immediately or on 30th, 90th and 180th. Subsequently, the gross anatomy was examined and endothelialization of device surface was evaluated by HE staining. 3 patients who had non-valvular AF and underwent LAAO in Zhongshan hospital, Fudan University using SimuLock® were enrolled in this study. They all had a follow-up of 3 months. Results All animals were implanted with the SimuLock® device. In 27.8% of animal cases, a LAA occluder of the "large umbrella and small disc" type which could adapt to LAA morphology well was employed, and all surpassed the specifications of existing occluders. None of residual shunt was observed all canines in 180 days post procedure. In addition, none adverse events were documents during the 6-month follow-up. In the first-in-human study, the SimuLock® occluder were successfully implanted in 3 subjects, all subjects achieved complete occlusion, without residual shunt > 3mm. The incidence of major adverse events, operation-related serious adverse events and device-related serious adverse events in all subjects were not documented in 3 months after operation. Conclusions In the animal experiment and first-in-human study, SimuLock® device showed the ability of adapting to various LAA morphology well and rapid endothelialization. The utilization of SimuLock® for LAAO exhibited high efficacy and safety.Central figure

Considerations for digitalisation of nickel electroforming

ABSTRACT This paper is a ‘follow-on’ from a paper previously published in this journal dealing with the laboratory to pilot scaling up approach using Industry 4.0 manufacturing methods. In particular, the paper reports a strategy for developing a model for the electroforming of nickel from a sulphamate electrolyte at laboratory scale which could subsequently provide an educated approach for transferring the process to a larger scale. At the laboratory scale, a rotating disc electrode assembly was used, which is a standard instrument to determine electrochemical parameters. Thereafter, small scale nickel discs were electroplated using this equipment, and a model of this process was developed and validated against those experimental results. These parameters were then used to actually produce electroforms in a prototype, 18 L tank system. Cross-validation between practical experiments and simulations followed which allowed for fine-tuning the model until it was consistently predicting the real process results within an acceptable error. Overall, it was found that a secondary current distribution model could be used for reasonably accurate description for the electroforming process, and could provide a quick virtual tool at a production facility.

An Electrically Small Patch Antenna Sensor for Salt Concentration Measurement of NaCl Solution.

In this paper, a complementary split-ring resonator (CSRR)-based patch antenna is proposed as a microwave sensor to measure the salt concentration of NaCl solution. The microwave sensor consists of an RF-4 substrate, where a small copper disc is attached on the top as the radiator, a larger copper disc integrated with two CSRRs is attached on the bottom side as the finite ground plane, and a coaxial feeding port is introduced at the ground plane center. During salt concentration sensing, only the top disc is immersed into NaCl solution. The results indicate that the proposed microwave sensor can measure salt concentrations ranging from 5‱ to 35‱ with a maximum sensitivity of 0.367 (kHz/(mg/L)). The proposed microwave sensor is low-cost, low-profile, electrically small, lightweight, and easy to fabricate, and it also can be applied to other solutions' concentration sensing.

Explaining the oblate morphology of dwarf spheroidals with wave dark matter perturbations

ABSTRACT We investigate whether the oblate, spheroidal morphology of common dwarf spheroidal galaxies (dSph) may result from the slow relaxation of stellar orbits within a halo of wave dark matter ($\psi$DM) when starting from an initial disc of stars. Stellar orbits randomly walk over a Hubble time, perturbed by the pervasive ‘granular’ interference pattern of $\psi$DM, that fully modulates the dark matter density on the de Broglie scale. Our simulations quantify the level of stellar disc thickening over the Hubble time, showing that distribution of stars is predicted to become an oblate spheroid of increasing radius, that plausibly accounts for the morphology of dSph galaxies. We predict a low level of residual rotation remains after a Hubble time at the 1–3 km/s level, depending on orientation, that compares with recent claims of rotation for some well-studied local dSph galaxies. This steady internal dynamical evolution may be witnessed directly with JWST for well-resolved dwarf galaxies, appearing more oblate with look back time and tending to small discs of young stars at high redshift.

Comparison In Vitro Study on the Interface between Skin and Bone Cell Cultures and Microporous Titanium Samples Manufactured with 3D Printing Technology Versus Sintered Samples.

Percutaneous implants osseointegrated into the residuum of a person with limb amputation need to provide mechanical stability and protection against infections. Although significant progress has been made in the biointegration of percutaneous implants, the problem of forming a reliable natural barrier at the level of the surface of the implant and the skin and bone tissues remains unresolved. The use of a microporous implant structure incorporated into the Skin and Bone Integrated Pylon (SBIP) should address the issue by allowing soft and bone tissues to grow directly into the implant structure itself, which, in turn, should form a reliable barrier to infections and support strong osseointegration. To evaluate biological interactions between dermal fibroblasts and MC3T3-E1 osteoblasts in vitro, small titanium discs (with varying pore sizes and volume fractions to achieve deep porosity) were fabricated via 3D printing and sintering. The cell viability MTT assay demonstrated low cytotoxicity for cells co-cultured in the pores of the 3D-printed and sintered Ti samples during the 14-day follow-up period. A subsequent Quantitative Real-Time Polymerase Chain Reaction (RT-PCR) analysis of the relative gene expression of biomarkers that are associated with cell adhesion (α2, α5, αV, and β1 integrins) and extracellular matrix components (fibronectin, vitronectin, type I collagen) demonstrated that micropore sizes ranging from 200 to 500 µm of the 3D printed and sintered Ti discs were favorable for dermal fibroblast adhesion. For example, for representative 3D-printed Ti sample S6 at 72 h the values were 4.71 ± 0.08 (α2 integrin), 4.96 ± 0.08 (α5 integrin), 4.71 ± 0.08 (αV integrin), and 1.87 ± 0.12 (β1 integrin). In contrast, Ti discs with pore sizes ranging from 400 to 800 µm demonstrated the best results (in terms of marker expression related to osteogenic differentiation, including osteopontin, osteonectin, osteocalcin, TGF-β1, and SMAD4) for MC3T3-E1 cells. For example, for the representative 3D sample S4 on day 14, the marker levels were 11.19 ± 0.77 (osteopontin), 7.15 ± 0.29 (osteonectin), and 6.08 ± 0.12 (osteocalcin), while for sintered samples the levels of markers constituted 5.85 ± 0.4 (osteopontin), 4.45 ± 0.36 (osteonectin), and 4.46 ± 0.3 (osteocalcin). In conclusion, the data obtained show the high biointegrative properties of porous titanium structures, while the ability to implement several pore options in one structure using 3D printing makes it possible to create personalized implants for the best one-time integration with both skin and bone tissues.

Uncovering accurate values of the polarization resistance in molten fluorides using electrochemical impedance spectroscopy

High-temperature operation and the presence of oxidizing impurities in molten chloride and fluoride salts pose significant corrosion risks to structural alloys in molten salt nuclear reactors. Electrochemical impedance spectroscopy (EIS) offers an operando, real-time method to study the instantaneous corrosion behavior of these materials non-destructively. However, signal noises may originate from sources extraneous to the electrochemical systems that limit the ability to perform quality impedance measurements in low-frequency regime where polarization resistance (Rp) dominates. Using the exposure of pure Cr in molten LiF-NaF-KF containing 1 wt% EuF3 at 600 °C as a model corrosion system, the extent of Non-Uniform Current and Potential (NUCP) distribution during an AC perturbation associate with the disk electrodes is evaluated in terms of two dimensionless correction factors kfRct(=Rct/Reff) and kfCdl(=Cdl/Ceff). Results show that a small area Cr disk electrode increases the transition frequency that marks the dominance of Rp to a conventional terminational frequency above 10−2 Hz, enabling a reliable charge-transfer resistance (Rct) value to be determined via circle fitting of an electrical equivalent circuit model (ECM) model. Experimental results were supported by EIS simulations considering commonly used ECM models that factor in the NUCP effect of disk geometries.

Ambiguous apparent motion in exchanging disks

A large and a small disk with radii R and r, side by side, exchange positions repetitively at 1.33 Hz. The motion is ambiguous. If r/ R < 0.8 then observers perceive a single large disk jumping back and forth across a small static disk. But if r/ R > 0.8, observers perceive two static disks that expand and contract in counter phase, with no motion across the gap between the disks. Observers respond to the movement of the centroid, which is greatest when r/ R < 0.8.

The MIRI Exoplanets Orbiting White dwarfs (MEOW) Survey: Mid-infrared Excess Reveals a Giant Planet Candidate around a Nearby White Dwarf

The MIRI Exoplanets Orbiting White dwarfs survey is a cycle 2 JWST program to search for exoplanets around dozens of nearby white dwarfs via infrared excess and direct imaging. In this Letter, we present the detection of mid-infrared excess at 18 and 21 μm toward the bright (V = 11.4) metal-polluted white dwarf WD 0310–688. The source of the IR excess is almost certainly within the system; the probability of background contamination is <0.1%. While the IR excess could be due to an unprecedentedly small and cold debris disk, it is best explained by a 3.0−1.9+5.5 M Jup cold (248 −61+84 K) giant planet orbiting the white dwarf within the forbidden zone (the region where planets are expected to be destroyed during the star’s red giant phase). We constrain the source of the IR excess to an orbital separation of 0.1–2 au, marking the first discovery of a white dwarf planet candidate within this range of separations. WD 0310–688 is a young remnant of an A- or late B-type star, and at just 10.4 pc, it is now the closest white dwarf with a known planet candidate. Future JWST observations could distinguish the two scenarios by either detecting or ruling out spectral features indicative of a planet atmosphere.

Visual Dose Monitoring for Whole Breast Radiation Therapy Treatments via Combined Cherenkov Imaging and Scintillation Dosimetry

PurposeThis study investigates scintillation dosimetry coupled with Cherenkov imaging for in vivo dose monitoring during whole breast radiotherapy (WBRT). Given recent observations of excess dose to the contralateral breast (CB), in vivo dosimetry (IVD) could help ensure accurate dose delivery and decrease risks of secondary cancer. This work presents a rapid, streamlined alternative to traditional IVD, providing direct visualization of measurement location relative to the treatment field on the patient. Methods and Materials10 WBRT patients consented under an IRB-approved protocol were monitored with scintillation dosimetry and always-on Cherenkov imaging, on both their treated and CB for one to three fractions. Scintillator dosimeters, small plastic discs 1mm thick and 15mm in diameter, were calibrated against optically-stimulated luminescent dosimeters (OSLDs) to generate an integral output-to-dose conversion, where integral output is measured in post-processing through a custom fitting algorithm. The discs have been extensively characterized in a previous study for various treatment conditions including beam energy and treatment geometry. ResultsN=44 dosimetry measurements were evaluated, including 22 treated breast and 22 CB measurements. Following integral output-to-dose calibration, in vivo scintillator dosimeters exhibited high linearity (R2=0.99) with paired OSLD readings across all patients. The difference between scintillation and OSLD dose measurements averaged 2.8% of the prescribed dose, or an absolute dose difference of approximately 7 cGy. ConclusionsIntegration of scintillation dosimetry with Cherenkov imaging offers an accurate, rapid alternative for in vivo dose verification in WBRT, circumventing the limitations of conventional point dosimeters. The additional benefit of visualizing measurement locations relative to the treatment field provides users an enhanced understanding of results and allows for detection of high dose gradients. Future work will explore the applicability of this technique across a broader range of radiotherapy treatments, aiming to streamline IVD practices.

Protostellar Disk Formation Regimes: Angular Momentum Conservation versus Magnetic Braking

Protostellar disks around young protostars exhibit diverse properties, with their radii ranging from less than ten to several hundred astronomical units. To investigate the mechanisms shaping this disk radius distribution, we compiled a sample of 27 Class 0 and I single protostars with resolved disks and dynamically determined protostellar masses from the literature. Additionally, we derived the radial profile of the rotational-to-gravitational-energy ratio in dense cores from the observed specific angular momentum profiles in the literature. Using these observed protostellar masses and rotational energy profile, we computed theoretical disk radii from the hydrodynamic and nonideal magnetohydrodynamic (MHD) models in Y.-N. Lee et al. and generated synthetic samples to compare with the observations. In our theoretical model, the disk radii are determined by hydrodynamics when the central protostar+disk mass is low. After the protostars and disks grow and exceed certain masses, the disk radii become regulated by magnetic braking and nonideal MHD effects. The synthetic disk radius distribution from this model matches well with the observations. This result suggests that hydrodynamics and nonideal MHD can be dominant in different mass regimes (or evolutionary stages), depending on the rotational energy and protostar+disk mass. This model naturally explains the rarity of large (>100 au) disks and the presence of very small (<10 au) disks. It also predicts that the majority of protostellar disks have radii of a few tens of astronomical units, as observed.

Placental lesions in systemic lupus erythematosus pregnancies associated with small for gestational age infants.

Up to a quarter of pregnant individuals with systemic lupus erythematosus (SLE) have small for gestational age (SGA) infants. We aimed to characterize placental pathology associated with SGA infants in SLE. We retrospectively analyzed SLE deliveries with placental analysis at UCSD from 11/2018-10/2023, comparing SLE pregnancies resulting in SGA to those that did not, and additionally, to matched pregnancies with SGA but without SLE. Placental analysis was available only for 28/70 (40%) SLE deliveries, which had high rates of adverse outcomes (75%). All exhibited at least one histopathologic abnormality. Key findings distinguishing 12 SLE placentas resulting in SGA infants (vs.16 without) included small placental disc for gestational age (100% vs 56%, p= 0.01), placental disc infarct (50% vs 6%, p= 0.02), and increased perivillous fibrin deposition (PVFD, 58% vs 0%, p= 0.001). All seven SLE placentas with increased PVFD resulted in SGA infants. Compared with matched non-SLE pregnancies with SGA (n = 36), the only distinguishing placental lesion was a higher prevalence of increased PVFD in SLE-associated SGA (58% vs 22%, p= 0.03). The higher prevalence of increased PVFD in placentas of SLE-associated SGA may indicate a specific mechanism of placental injury leading to SGA in this context. Thus, its presence, particularly in context of SGA, should prompt providers to screen for an underlying autoimmune disease, including SLE. Systematic placental examination in context of SLE and associated autoimmune diseases could help evaluate responses to existing therapies, comparative studies of novel therapies, and correlation to adverse outcomes.

Task-based assessment for neural networks: evaluating undersampled MRI reconstructions based on human observer signal detection.

Recent research explores using neural networks to reconstruct undersampled magnetic resonance imaging. Because of the complexity of the artifacts in the reconstructed images, there is a need to develop task-based approaches to image quality. We compared conventional global quantitative metrics to evaluate image quality in undersampled images generated by a neural network with human observer performance in a detection task. The purpose is to study which acceleration (2×, 3×, 4×, 5×) would be chosen with the conventional metrics and compare it to the acceleration chosen by human observer performance. We used common global metrics for evaluating image quality: the normalized root mean squared error (NRMSE) and structural similarity (SSIM). These metrics are compared with a measure of image quality that incorporates a subtle signal for a specific task to allow for image quality assessment that locally evaluates the effect of undersampling on a signal. We used a U-Net to reconstruct under-sampled images with 2×, 3×, 4×, and 5× one-dimensional undersampling rates. Cross-validation was performed for a 500- and a 4000-image training set with both SSIM and MSE losses. A two-alternative forced choice (2-AFC) observer study was carried out for detecting a subtle signal (small blurred disk) from images with the 4000-image training set. We found that for both loss functions, the human observer performance on the 2-AFC studies led to a choice of a 2× undersampling, but the SSIM and NRMSE led to a choice of a 3× undersampling. For this detection task using a subtle small signal at the edge of detectability, SSIM and NRMSE led to an overestimate of the achievable undersampling using a U-Net before a steep loss of image quality between 2×, 3×, 4×, 5× undersampling rates when compared to the performance of human observers in the detection task.

Rocky planet formation in compact disks around M dwarfs

Due to the improvements in radial velocity and transit techniques, we know that rocky or rocky-icy planets, in particular close-in super-Earths in compact configurations, are the most common ones around M dwarfs. On the other hand, thanks to the high angular resolution of ALMA we know that many disks around very low-mass stars (between 0.1 and 0.5 M$_ are rather compact and small (without observable substructures and radius less than 20 au), which favors the idea of an efficient radial drift that could enhance planet formation in the terrestrial zone. Our aim was to investigate the potential formation paths of the observed close-in rocky exoplanet population around M dwarfs, especially close-in super-Earths, assuming that planet formation could take place in compact disks with an efficient dust radial drift. We developed N-body simulations that include a sample of embryos growing by pebble accretion exposed to planet-disk interactions, star-planet tidal interactions, and general relativistic corrections that include the evolution of the luminosity, radius, and rotational period of the star. For a star of 0.1 M$_ we considered different gas disk viscosities and initial embryo distributions. We also explored planet formation by pebble accretion around stars of 0.3 M$_ and 0.5 M$_ Lastly, for each stellar mass, we ran simulations that include a sample of embryos growing by planetesimal accretion instead of pebble accretion. Our main result is that the sample of simulated planets that grow by pebble accretion in a gas disk with low viscosity ($ $) can reproduce the close-in low-mass exoplanet population around M dwarfs in terms of multiplicity, mass, and semi-major axis. Furthermore, we found that a gas disk with high viscosity ($ $), and thus lower pebble accretion rates, cannot reproduce the observed planet masses as no planet more massive than 0.5 M$_ could be formed in our simulations. In addition, we show that planetesimal accretion favors the formation of smaller planets than pebble accretion does. Whether this planet population truly exists remains unknown with the current instrumental sensitivity. Rocky planet formation around M dwarfs can take place in compact and small dust disks driven by an efficient radial drift in a gas disk with low viscosity ($ $). This result points toward a new approach in the direction of the disk conditions needed for rocky planet formation around very low-mass stars.

Myopia and Other Refractive Error and Their Relationships to Glaucoma Screening.

A large disk, a large parapapillary delta zone and a long axial length may be used as screening criteria to detect glaucomatous optic neuropathy in highly myopic eyes. To describe aspects for screening of glaucomatous optic neuropathy in dependence of refractive error, under special consideration of high myopia. Studies on the anatomy of the myopic optic nerve head and results of investigations on the relationship between glaucomatous optic neuropathy and axial myopia were included. In the range from hyperopia to moderate myopia, refractive error is not a strong glaucoma risk factor and may not be included in glaucoma screening strategies. Care should be taken, that in moderate myopia, a shift of Bruch´s membrane opening usually into the temporal direction leads to parapapillary gamma zone and a corresponding shortening of the horizontal disk diameter. In these moderately myopic eyes, a secondarily small optic disk with a correspondingly small optic cup should not lead to an overlooking of intrapapillary glaucomatous changes. Prevalence of glaucomatous or glaucoma-like optic nerve atrophy (GOA) steeply increases with longer axial length in highly myopic eyes (cutoff approximately -8 diopters/axial length 26.5mm), with prevalences higher than 50% in extremely high myopia. Besides longer axial length, morphological parameters associated with GOA in highly myopic eyes are a secondarily enlarged disk and large parapapillary delta zone. Both parameters, together with long axial length, may be used as screening criteria in high myopia for GOA. The latter is characterized by an abnormal neuroretinal rim shape, that is, vessel kinking close to the intrapapillary disk border. Factors associated with nonglaucomatous optic neuropathy are larger gamma zone and longer axial length, potentially due to an axial elongation-related retinal nerve fiber stretching.

A study of clinical &amp; radiological outcomes of small single enhancing lesions in CT brain - in a tertiary care hospital

Introduction Small single enhancing lesion in CT (SSECT) scan as an entity came into existence in India in early 1980, with the advent of CT scan. Tandon et al3 labeled them as intracranial tuberculomas. They identified two types of lesions based on the appearance of the lesion in the C T Scan brain. Small ring and disc lesions were called as immature tuberculomas and large lobulated lesions were called as mature tuberculomas. ATT was invariably started in these patients. Sethi et al5 &amp; Bansal et al6 noted that these lesions disappeared spontaneously without treatment. Natarajan and Arjundas et al37 at the Institute of Neurology, Chennai also noted spontaneous disappearance of these lesions without specific treatment. The exact cause of these lesions could not be deciphered because apart from tuberculoma, cysticercus granuloma, pyogenic abscess, metastases, fungal granuloma, and glioma had been reported to cause similar appearance in CT scan brain as more centers acquired C.T. Scan facility. Hence the exact aetiology of these lesions became a subject of speculation. A significant breakthrough came in 1987 at Vellore 8 when stereo tactic biopsy was done on 15 patients with SSECT. Most of the lesions were identified as cysticercus and none were of tuberculous etiology. Bhargava and Tandon in 1988 and Wadia, Makhalle in 19863,4, found evidence of tuberculous lesions in histopathology. However they failed in defining the size of the lesion. Rajshekhar et al8 then defined a small single lesion based on CT appearance as “A solitary, contrast-enhancing lesion of less than 20- mm diameter lesion without severe cerebral edema (no midline shift)”.this definition is often equated to cysticercous granuloma but there is every possibility that these lesions could be a tuberculoma.

All-optical multichannel switch and slow light based on dynamically tunable plasmon-induced transparency

The triple plasmon-induced transparency (PIT) effect based on a metal–insulator–metal waveguide structure comprising two groups of big and small disk resonators (BSDRs) is investigated theoretically and numerically. As a tool employed to explain the PIT, N-order coupled mode theory (CMT), is established, and the calculated results of the triple-PIT effect exhibit excellent consistency with finite-difference time-domain simulations. The influence of the separation between the small disk resonators on the triple-PIT response is discussed in detail through the dynamical equation. Further research shows that the central wavelengths of the triple-PIT transmission window can be adjusted with extremely low pump intensity and ultrafast optical response when monolayer graphene covers the surface of the BSDRs. Meaningfully, light traveling at resonant wavelengths can be effectively slowed down, with the highest group index reaching 368. Based on the PIT effect, a low-power and ultrafast switch is realized with a modulation amplitude of more than 93% at the corresponding wavelengths of the eight depressions. Thus, not only do the insights put forward new ideas, to the best of our knowledge, for highly tunable optoelectronic devices, but the results from the N-order CMT also offer new theory progress and references in the plasmonic waveguide structures.