- Is there a survival advantage in diagnosing endometrial cancer in asymptomatic postmenopausal patients? An Israeli Gynecology Oncology Group study. [Journal Article]
- AJAm J Obstet Gynecol 2018 May 21
- CONCLUSIONS: Endometrial cancer diagnosed in asymptomatic post-menopausal women is not associated with higher survival rates. Operative hysteroscopy/curettage procedures in asymptomatic patients with ultrasonographically diagnosed endometrial polyps or thick endometrium are rarely indicated. It is reasonable to reserve these procedures for patients whose ultrasonographic findings demonstrate significant change over time.
- Ultralow Damping in Nanometer-Thick Epitaxial Spinel Ferrite Thin Films. [Journal Article]
- NLNano Lett 2018 May 24
- Pure spin currents, unaccompanied by dissipative charge flow, are essential for realizing energy-efficient nanomagnetic information and communications devices. Thin-film magnetic insulators have been...
Pure spin currents, unaccompanied by dissipative charge flow, are essential for realizing energy-efficient nanomagnetic information and communications devices. Thin-film magnetic insulators have been identified as promising materials for spin-current technology, since they are thought to exhibit lower damping compared to their metallic counterparts. However, insulating behavior is not a sufficient requirement for low damping, as evidenced by the very limited options for low-damping insulators. Here, we demonstrate a new class of nanometer-thick ultralow-damping insulating thin films, based on design criteria that minimize orbital angular momentum and structural disorder. Specifically, we show ultralow damping in <20-nm thick spinel-structure magnesium aluminum ferrite (MAFO), in which magnetization arises from Fe3+ ions with zero orbital angular momentum. These epitaxial MAFO thin films exhibit a Gilbert damping parameter of ≈0.0015 and negligible inhomogeneous linewidth broadening, resulting in narrow half-width-at-half-maximum linewidths of ≈0.6 mT around 10 GHz. Our findings offer an attractive thin-film platform for enabling integrated insulating spintronics.
- Effects of Enhanced Flexibility and Pore Size Distribution on Adsorption-Induced Deformation of Mesoporous Materials. [Journal Article]
- LLangmuir 2018 May 24
- We present a new model of adsorption-induced deformation of mesoporous solids. The model is based on a simplified version of Local Density Functional Theory in the framework of solvation free energy....
We present a new model of adsorption-induced deformation of mesoporous solids. The model is based on a simplified version of Local Density Functional Theory in the framework of solvation free energy. Instead of density, which is treated as constant here, we used the film thickness and pore radius as order parameters. This allows us to obtain a self-consistent system of equations describing simultaneously the processes of gas adsorption and adsorbent deformation, as well as conditions for capillary condensation and evaporation. In the limit of infinitely rigid pore walls, when the film becomes several monolayers thick the model reduces to the well-known Derjaguin-Broekhoff-de Boer (DBdB) theory for pores with cylindrical geometry. We have investigated the effects of enhanced flexibility of the solid as well as the influence of the pore size distribution on the adsorption/deformation process. The formulation of the theory allows to determine the average pore size and its width from desorption branch of the deformation isotherm only. The model reproduces the non-monotonic behavior of the deformation isotherm at low relative pressure. Furthermore we discuss the effect of rigidity of the adsorbent on the pore size distribution, showing qualitatively different results of the adsorption isotherms for rigid and highly flexible materials. In particular the shift of evaporation pressure to lower values and the absence of a limiting value of the loading at high relative pressure. We discuss as well the results of the theory with respect to experimental data obtained from the literature.
- Spatial and Temporal Variability in Emissions of Fluorinated Gases from a California Landfill. [Journal Article]
- ESEnviron Sci Technol 2018 May 24
- Emissions of twelve F-gases and methane were quantified using large-scale static chambers as a function of cover type (daily, intermediate, final) and seasonal variation (wet, dry) at a California la...
Emissions of twelve F-gases and methane were quantified using large-scale static chambers as a function of cover type (daily, intermediate, final) and seasonal variation (wet, dry) at a California landfill. The majority of the F-gas fluxes was positive and varied over 7 orders of magnitude across the cover types in a given season (wet: 10-8 to 10-1 g/m2-day; dry: 10-9 to 10-2 g/m2-day). The highest fluxes were from active filling areas with thin, coarse-grained daily covers, whereas the lowest fluxes were from the thick, fine-grained final cover. Historical F-gas replacement trends, waste age, and cover soil geotechnical properties affected flux with significantly lower F-gas fluxes than methane (10-4 to 10+1 g/m2-day). Both flux and variability of flux decreased with the order: daily to intermediate to final covers; coarser to finer cover materials; low to high fines content cover soils; high to low degree of saturation cover soils; and thin to thick covers. Cover-specific F-gas fluxes were approximately one order of magnitude higher in the wet than dry season, due to combined effects of comparatively high saturations, high void ratios, and low temperatures. Emissions were primarily controlled by type and relative areal extent of cover materials and secondarily by season.
- Increased diagnostic confidence in the diagnosis of pituitary micro-lesions with the addition of three-dimensional sampling perfection with application-optimized contrasts using different flip-angle evolutions sequences. [Journal Article]
- ARActa Radiol 2018 Jan 01; :284185118774954
- Background Conventional magnetic resonance imaging (MRI) is adversely affected by thick slices, small intersection gaps, and the partial volume effect, leading to the missed diagnosis or misdiagnosis...
Background Conventional magnetic resonance imaging (MRI) is adversely affected by thick slices, small intersection gaps, and the partial volume effect, leading to the missed diagnosis or misdiagnosis of pituitary micro-lesions. Purpose To evaluate the diagnostic yield of three-dimensional sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-T2 SPACE) sequences compared with a standard MRI protocol for the diagnosis of pituitary micro-lesions. Material and Methods The MRI findings of 664 patients with clinically suspected pituitary lesions were retrospectively analyzed. All patients underwent coronal 3D-T2 SPACE sequences followed by T1-weighted (T1W) imaging. Conventional scanning sequences included coronal and sagittal T1W imaging and post-contrast enhanced coronal and sagittal T1 imaging. All images were independently evaluated by two experienced neuroradiologists. The inter-observer agreement was analyzed using kappa statistics. Results Compared with conventional sequences, there was an increase in diagnostic confidence of 60.3% for the diagnosis of pituitary micro-lesions with the addition of 3D-T2 SPACE sequences. The lesion conspicuity scores of combined conventional and 3D-T2 SPACE sequences were significantly higher than those of conventional imaging (z = -6.403, P < 0.01) and 3D-T2 SPACE sequences (z = -4.243, P < 0.01). In addition, the inter-observer agreement of 3D-T2 SPACE sequences was good (κ = 0.826). Conclusion Combined with routine sequences, post-contrast enhanced 3D-T2 SPACE sequences effectively improve diagnostic confidence in the diagnosis of pituitary micro-lesions. Post-contrast enhanced 3D-T2 SPACE is suitable for detecting pico-adenomas, micro-lesions adjacent to the cavernous sinuses or sellar floor, lesions between the anterior and posterior lobes, and lesions with early phase enhancement.
- The Global Neurological Burden of Tuberculosis. [Journal Article]
- SNSemin Neurol 2018; 38(2):226-237
- Central nervous system (CNS) involvement of tuberculosis (TB) is the most severe manifestation of TB and accounts for approximately 5 to 10% of all extrapulmonary TB (EPTB) cases and approximately 1%...
Central nervous system (CNS) involvement of tuberculosis (TB) is the most severe manifestation of TB and accounts for approximately 5 to 10% of all extrapulmonary TB (EPTB) cases and approximately 1% of all TB cases. TB meningitis (TBM) is the most common form of CNS TB, though other forms occur, often in conjunction with TBM, including intracranial tuberculomas, tuberculous brain abscesses, and spinal tubercular arachnoiditis. CNS TB often presents with nonspecific clinical features that mimic symptoms of other neurological conditions, often making diagnosis difficult. Defining neuroimaging characteristics of TBM include thick basal meningeal enhancement, hydrocephalus, and parenchymal infarctions most commonly involving the basal ganglia and internal capsule. Traditional cerebrospinal fluid sample analysis frequently requires lengthy times-to-result and have low sensitivity. Given the pitfalls of conventional CNS TB diagnostic methods, various molecular-based methods, including immunoassays and polymerase chain reaction (PCR)-based assays have emerged as alternative diagnostic tools due to their rapidity, sensitivity, and specificity. Expert panels on TBM have recently emphasized the need for standard research procedures with updated case definitions and standardized study methods, which will hopefully pave the way for more robust multicenter international studies. In this article, we review the epidemiology, diagnosis, molecular factors associated with disease presentation and outcome, and treatment of CNS TB.
- Third-order aberration coefficients of a thick lens with a given value of its focal length. [Journal Article]
- AOAppl Opt 2018 May 20; 57(15):4263-4266
- The formulas are derived for calculation of the third-order aberration (Seidel) coefficients for a thick spherical lens in air with a given value of its focal length and for an object at infinity in ...
The formulas are derived for calculation of the third-order aberration (Seidel) coefficients for a thick spherical lens in air with a given value of its focal length and for an object at infinity in this paper. The explicit analytic dependence of individual aberration coefficients on a lens thickness is derived. Equations were described for the re-calculation of aberration coefficients for a different value of focal length and different values of entrance pupil and object positions. Such formulas make it possible to analyze analytically an influence of the lens thickness on lens aberration properties and the replacement of a thin lens optical system by a thick lens model.
- Visible light induced electropolymerization of suspended hydrogel bioscaffolds in a microfluidic chip. [Journal Article]
- BSBiomater Sci 2018 May 23
- The development of microengineered hydrogels co-cultured with cells in vitro could advance in vivo bio-systems in both structural complexity and functional hierarchy, which holds great promise for ap...
The development of microengineered hydrogels co-cultured with cells in vitro could advance in vivo bio-systems in both structural complexity and functional hierarchy, which holds great promise for applications in regenerative tissues or organs, drug discovery and screening, and bio-sensors or bio-actuators. Traditional hydrogel microfabrication technologies such as ultraviolet (UV) laser or multiphoton laser stereolithography and three-dimensional (3D) printing systems have advanced the development of 3D hydrogel micro-structures but need either expensive and complex equipment, or harsh material selection with limited photoinitiators. Herein, we propose a simple and flexible hydrogel microfabrication method based on a ubiquitous visible-light projection system combined with a custom-designed photosensitive microfluidic chip, to rapidly (typically several to tens of seconds) fabricate various two-dimensional (2D) hydrogel patterns and 3D hydrogel constructs. A theoretical layer-by-layer model that involves continuous polymerizing-delaminating-polymerizing cycles is presented to explain the polymerization and structural formation mechanism of hydrogels. A large area of hydrogel patterns was efficiently fabricated without the usage of costly laser systems or photoinitiators, i.e., a stereoscopic mesh-like hydrogel network with intersecting hydrogel micro-belts was fabricated via a series of dynamic-changing digital light projections. The pores and gaps of the hydrogel network are tunable, which facilitates the supply of nutrients and discharge of waste in the construction of 3D thick bio-models. Cell co-culture experiments showed the effective regulation of cell spreading by hydrogel scaffolds fabricated by the new method presented here. This visible light enabled hydrogel microfabrication method may provide new prospects for designing cell-based units for advanced biomedical studies, e.g., for 3D bio-models or bio-actuators in the future.
- Wide-Band "Black Silicon" with Atomic Layer Deposited NbN. [Journal Article]
- NNanotechnology 2018 May 23
- Antireflection surfaces are often utilized in optical components to reduce undesired reflection and increase absorption. We report on black silicon (b-Si) with dramatically enhanced absorption over a...
Antireflection surfaces are often utilized in optical components to reduce undesired reflection and increase absorption. We report on black silicon (b-Si) with dramatically enhanced absorption over a broad wavelength range (250-2500 nm) achieved by applying a 10-15 nm conformal coating of NbN with atomic layer deposition (ALD). The improvement is especially pronounced in the near infrared (NIR) range of 1100-2500 nm where absorption is increased by >90%. A significant increase of absorption is also observed over the ultraviolet (UV) range of 200-400 nm. Preceding NbN deposition with a nanostructured ALD Al<sub>2</sub>O<sub>3</sub> (n-Al<sub>2</sub>O<sub>3</sub>) coating to enhance the NbN texture was also examined. Such texturing further improves absorption in the NIR, especially at longer wavelengths, strong absorption up to 4-5 μm wavelengths has been attested. For comparison, double side polished silicon and sapphire coated with 10 nm-thick NbN exhibited absorption of only ~55% in the NIR range of 1100-2500 nm. The results suggest a positive correlation between the surface area of NbN coating and optical absorption. Based on the wide-band absorption, the presented NbN-coated b-Si may be an attractive candidate for use in e.g. spectroscopic systems, infrared microbolometers.
New Search Next
- Highly Oriented Monolayer Graphene Grown on a Cu/Ni(111) Alloy Foil. [Journal Article]
- ANACS Nano 2018 May 23
- Fast-growth of single crystal monolayer graphene by CVD using methane and hydrogen has been achieved on "homemade" single crystal Cu/Ni(111) alloy foils over large area. Full coverage was achieved in...
Fast-growth of single crystal monolayer graphene by CVD using methane and hydrogen has been achieved on "homemade" single crystal Cu/Ni(111) alloy foils over large area. Full coverage was achieved in 5 min or less for a particular range of composition (1.3 at.% to 8.6 at.% Ni), as compared to 60 min for a pure Cu(111) foil under identical growth conditions. These are the bulk atomic percentages of Ni, as a superstructure at the surface of these foils with stoichiometry Cu6Ni1 (for 1.3 to 7.8 bulk at.% Ni in the Cu/Ni(111) foil) was discovered by low energy electron diffraction (LEED). Complete large area monolayer graphene films are either single crystal or close to single crystal, and include folded regions that are essentially parallel and that were likely wrinkles that "fell over" to bind to the surface; these folds are separated by large, wrinkle-free regions. The folds occur due to the buildup of interfacial compressive stress (and its release) during cooling of the foils from 1075 °C to room temperature. The fold heights measured by atomic force microscopy (AFM) and scanning tunneling microscopy (STM) prove them to all be 3 layers thick, and scanning electron microscopy (SEM) imaging shows them to be around 10 to 300 nm wide and separated by roughly 20 μm. These folds are always essentially perpendicular to the steps in this Cu/Ni(111) substrate. Joining of well-aligned graphene islands (in growths that were terminated prior to full film coverage) was investigated with high magnification SEM and aberration-corrected high-resolution transmission electron microscopy (TEM) as well as AFM, STM, and optical microscopy. These methods show that many of the "join regions" have folds, and these arise from interfacial adhesion mechanics (they are due to the buildup of compressive stress during cool-down, but these folds are different than for the continuous graphene films-they occur due to "weak links" in terms of the interface mechanics). Such Cu/Ni(111) alloy foils are promising substrates for the large-scale synthesis of single-crystal graphene film.