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Spontaneous spinal epidural hematoma (SSEH) as an initial presentation of polycythemia vera (PV) is rare. It can present with the features ranging from simple back pain to complete paraplegia depending on the site of the spinal compression. Herein, we describe a case of undiagnosed PV presented as back pain with radiation to the chest wall in a 46-year-old male patient and subsequently diagnosed with spontaneous spinal epidural hemorrhage. To the best of our knowledge, only one case of spinal epidural hematoma-related PV has been reported so far. Emergent decompressive laminectomy was done within 10 h of initial presentation with excellent clinical outcome. Therefore, this condition must be promptly diagnosed and treated with decompression surgery to minimize the risk of neurological complication.

Reversible-deactivation radical polymerization (RDRP) serves as a powerful tool nowadays for the preparations of unique linear and non-linear macromolecules. In this study, enhanced spin capturing polymerizations (ESCPs) of styrene (St) and tert-butyl acrylate (tBA) monomers were, respectively, conducted in the presence of difunctional (1Z,1′Z)-1,1′-(1,4-phenylene) bis (N-tert-butylmethanimine oxide) (PBBN) nitrone. Four-arm (PSt)4 and (PtBA)4 star macroinitiators (MIs) can be afforded. By correspondingly switching the second monomer (i.e., tBA and St), miktoarm star copolymers (μ-stars) of (PSt)2-μ-(PtBA-b-PSt)2 and (PtBA)2-μ-(PSt-b-PtBA)2) were thus obtained. We further conducted hydrolysis of the PtBA segments to PAA (i.e., poly(acrylic acid)) in μ-stars to afford amphiphilic μ-stars of (PSt)2-μ-(PAA-b-PSt)2 and (PAA)2-μ-(PSt-b-PAA)2. We investigated each polymerization step and characterized the obtained two sets of “sequence-isomeric” μ-stars by FT-IR, 1H NMR, differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA). Interestingly, we identified their physical property differences in the case of amphiphilic μ-stars by water contact angle (WCA) and atomic force microscopy (AFM) measurements. We thus proposed two microstructures caused by the difference of polymer chain sequences. Through this polymerization transformation (Ŧ) approach (i.e., ESCP-Ŧ-NMP), we demonstrated an interesting and facile strategy for the preparations of μ-stars with adjustable/switchable interior and exterior polymer structures toward the preparations of various nanomaterials.

The properties of two-dimensional (2D) materials are readily affected by their surroundings. Therefore, the underlying substrates and surrounding materials always disturb the pristine properties of 2D materials. Herein, we describe how the pristine properties of suspended 2D materials can be precisely extracted from Raman and photoluminescence (PL) spectra with great signal enhancements by taking advantage of both air gap suspension and nanocavity enhancement effects. The modes of the Raman emission lines were enhanced to almost the same degree when the 2D materials were positioned over the nanocavity: the 2D/G peaks of suspended single-layer graphene (SLG) and the E12g/A1g peaks of MoS2 were significantly enhanced almost equally. Moreover, recording Raman and PL spectra at different positions of the suspended 2D materials was a very powerful tool for observing charge transfer between the pristine 2D materials and the surrounding materials. We also found that the residual holes of the suspended SLG could ...

The core assumption of Fowler theory is that excited hot electrons are distributed isotropically in momentum space inside a metal, and only a small fraction of the hot electrons within the emission cone perpendicular to the Schottky junction can possibly be injected into the semiconductor contact. A clearer understanding of the direction and momentum space of hot electrons should aid the development of various hot electron-based devices. In this study, in contrast to the assumption of Fowler theory, we first proved experimentally that the direction of hot electrons is highly related to the polarization state of the incident light. Furthermore, the anisotropic movement of hot electrons can be exploited, through the application of a magnetic field, to modulate the optoelectronic response to silicon (Si)-based photodetectors that operate at optical telecommunication wavelengths. Instead of using a noble metal, we applied nickel (Ni), a ferromagnetic material, to construct a hot electron-based photodetector for the detection of infrared (IR) radiation with photon energy well below the band edge of Si. We designed a series of experiments to verify the directionality and transport of hot electrons within the Ni–Si Schottky diode. When a magnetic field was applied to the device, the effects of Lorentz force and anisotropic magnetoresistance (AMR) greatly affected the transport of hot electrons. Furthermore, taking advantage of the anisotropic movement of hot electrons and magnetic effects, we could selectively enhance or weaken the IR radiation-induced signals. In addition, our device could be switched from polarization-insensitive to polarization-sensitive by applying a magnetic field. To the best of our knowledge, this study, combining the electrical, magnetic, and optical effects of hot electrons and Si-based devices, is the first to modulate the efficiency of Si-based photodetectors working at optical telecommunication wavelengths. This strategy would, presumably, also be potentially very useful when applied to other hot electron-based systems and devices.

Large-area graphene is commonly prepared through chemical vapor deposition (CVD); in situ and nondestructive methods for its characterization are desirable. In this paper, we demonstrate a practical method—exploiting magnetic dipole resonance and coupling effects—with which the Raman signals of graphene on copper (Cu) foil can be directly, faithfully, and greatly enhanced. The magnetic dipole resonance of a silicon nanoparticle (SiNP) can effectively couple its electromagnetic field with the Cu foil to induce an enormous electric field located solely at the position of the SiNP on the graphene. The coupled electromagnetic field can lead to hot spots of high electric field intensity (E2/E02 = 123.2) within the graphene. Even when we positioned only a few SiNPs upon the graphene/Cu foil, we obtained a Raman signal enhancement (ca. 206 times) much greater than that of graphene transferred onto a 300 nm oxide film (ca. 12 times). From a series of experiments comparing the Raman signals of graphene before and ...

Background: Most Aristolochiaceae plants are prohibited due to aristolochic acid nephropathy (AAN), except Xixin ( Asarum spp. ). Xixin contains trace amounts of aristolochic acid (AA) and is widely used in Traditional Chinese Medicine. Methylglyoxal and D-lactate are regarded as biomarkers for nephrotoxicity. Thus, this study aimed to evaluate tubulointerstitial injury and interstitial renal fibrosis by determining urinary methylglyoxal and D-lactate after withdrawal of low-dose AA in a chronic mouse model. Methods: C3H/He mice in the AA group ( n =24/group) were given ad libitum access to distilled water containing 3 µg/mL AA (0.5 mg/kg/day) for 56 days and drinking water from days 57 to 84. The severity of tubulointerstitial injury and fibrosis were evaluated using the tubulointerstitial histological score (TIHS) and Masson’s trichrome staining. Urinary and serum methylglyoxal were determined by high-performance liquid chromatography (HPLC); urinary D-lactate were determined by column-switching HPLC. Results: After AA withdrawal, serum methylglyoxal in the AA group increased from day 56 (429.4±48.3 μg/L) to 84 (600.2±99.9 μg/L), and peaked on day 70 (878.3±171.8 μg/L; p Conclusions: Methylglyoxal is induced after AA-induced tubulointerstitial injury, thus methylglyoxal excretion and metabolism may be a detoxification and repair strategy. A low cumulative AA dose is the key factor that limits tubulointerstitial injury and repair. Thus, AA-containing herbs, especially Xixin, should be used at low doses for short durations (less than one month).

In this paper, a method for automatically separating the mixed circular fringe patterns based on the fractional Fourier transform (FrFT) analysis is proposed. Considering the mixed two-dimensional (2-D) Gaussian-based circular fringe patterns, detected by using an image sensor, we propose a method that can efficiently determine the number and parameters of each separated fringe patterns by using the FrFT due to the observed higher sparsity in the frequency domain than that in the spatial domain. First, we review the theory of FrFT and the properties of the 2-D circular fringe patterns. By searching the spectral intensities of the various fractional orders in the FrFT projected along both the frequency axes, the proposed method can automatically determine the total fringe number, the central position, binary phase, and the maximum fringe width of each 2-D circular fringe pattern. In the experimental results, both the computer-simulated and optically mixed fringe patterns are used to verify the proposed method. In addition, the additive Gaussian noise effects on the proposed method are investigated. The proposed method can still successfully separate the mixed fringe pattern when the signal-to-noise ratio is higher than 7 dB.

We developed a nanocavity structure to enhance light outcoupling from different two-dimensional (2D) materials. The Raman and photoluminescence (PL) light emissions from 2D materials were enhanced dramatically while maintaining band-to-band ratios and peak positions precisely.

In this study, we found that the large area of electromagnetic field hot zone induced through magnetic dipole resonance of metal-free structures can greatly enhance Raman scattering signals. The magnetic resonant nanocavities, based on high-refractive-index silicon nanoparticles (SiNPs), were designed to resonate at the wavelength of the excitation laser of the Raman system. The well-dispersed SiNPs that were not closely packed displayed significant magnetic dipole resonance and gave a Raman enhancement per unit volume of 59 347. The hot zones of intense electric field were generated not only within the nonmetallic NPs but also around them, even within the underlying substrate. We observed experimentally that gallium nitride (GaN) and silicon carbide (SiC) surfaces presenting very few SiNPs (coverage: 50%) Raman signals. In contrast, the Raman signals of the underlying substrates were not enhanced by gold nanoparticles (AuNPs), even though these NPs displayed a localized surface plasmon resonance (LSPR) phenomenon. A comparison of the areas of the electric field hot zones (E 2 > 10) generated by SiNPs undergoing magnetic dipole resonance with the electric field hot spots (E 2 > 10) generated by AuNPs undergoing LSPR revealed that the former was approximately 70 times that of the latter. More noteworthily, the electromagnetic field hot zone generated from the SiNP is able to extend into the surrounding and underlying media. Relative to metallic NPs undergoing LSPR, these nonmetallic NPs displaying magnetic dipole resonance were more effective at enhancing the Raman scattering signals from analytes that were underlying, or even far away from, them. This application of magnetic dipole resonance in metal-free structures appears to have great potential for use in developing next-generation techniques for Raman enhancement.

Kelley and Lai (2011) recently proposed the use of accuracy in parameter estimation (AIPE) for sample size planning in structural equation modeling. The sample size that reaches the desired width for the confidence interval of root mean square error of approximation (RMSEA) is suggested. This study proposes a graphical extension with the AIPE approach, abbreviated as GAIPE, on RMSEA to facilitate sample size planning in structural equation modeling. GAIPE simultaneously displays the expected width of a confidence interval of RMSEA, the necessary sample size to reach the desired width, and the RMSEA values covered in the confidence interval. Power analysis for hypothesis tests related to RMSEA can also be integrated into the GAIPE framework to allow for a concurrent consideration of accuracy in estimation and statistical power to plan sample sizes. A package written in R has been developed to implement GAIPE. Examples and instructions for using the GAIPE package are presented to help readers make use of th...

The biocompatible thin film metallic glass (TFMGs) materials can be used to modify the substrate material due to their good corrosion resistance and adequate biocompatibility. In this work, five Fe–Zr–Nb TFMGs were fabricated on Si wafer and AISI420 stainless steel disk substrates using three pure targets co-sputtering system. The niobium target power was adjusted to grow TFMGs with different Nb contents ranging from 21.7 to 26.7 at%. Very fine and dense featureless microstructure was discovered for each Fe–Zr–Nb TFMG. The hardness, elastic modulus, H/E and H3/E2 ratios of Fe–Zr–Nb TFMG increased with increasing Nb content. Good adhesion property was revealed for each TFMG. The corrosion resistance of the bare AISI420 stainless steel disk was greatly improved by the deposited Fe–Zr–Nb TFMG. Very good biocompatibility and MG63 cell viability were also found for TFMGs implying their potential application as biomedical materials.

In-situ CVD doping and laser anneal can reach [P] and tensile strain as high as 2×1020 cm−3 and 0.34%, respectively, in Ge on SOI with low defect density and high activation rate (nearly 100% near the surface), and enables high performance of the junctionless (JL) Ge gate-all-around (GAA) nFETs. The device with the W fin of 13 nm, EOT of 10 nm, and nominal L G of 280 nm has I on = 350 µA/µm, I on /I off = 3×106, SS = 185 mV/dec, and DIBL = 16 mV/V. The device with the W fin of 9 nm and EOT of ∼ 0.8 nm achieves the record high I on of 828 µA/µm at V GS - V T = 1.5 V and V DS = 2 V with DIBL = 54 mV/V, I on /I off = 1×105 and SS = 150 mV/dec. Besides the epitaxial tensile strain (0.34%) generated by laser anneal due to the misfit of thermal expansion coefficients between Ge and Si, the enhanced tensile strain by the microbridge structure is also beneficial for I on . The drain current enhancement of ∼40% is achieved under the mechanical uniaxial tensile strain of ∼0.25% due to sub-band splitting and carrier repopulation into the L4 valleys with the small conductive effective mass. The non-uniform shape of Ge channel with a minimum width at the center leads to enhanced I on as compared to uniform channel. The extracted mobility of JL devices increases with increasing temperature, indicating the domination of impurity scattering. The threshold voltage of JL devices has the negative temperature coefficient and EOT scaling reduces the temperature dependence.

To meet the development of the international tourism market, international tourist hotels have gradually replaced tourist hotels in Taiwan. Owing to the industrial trend, foreign language proficiency, which is essentially communicative skill training required for undergraduate students/learners and industrial practitioners, has been significantly emphasized and noticed among educational institutions and hospitality industries. This study namely aimed at constructing a English curriculum model for hospitality field which infused from English for Specific Purposes. The modified Delphi technique was adopted to determine the relevant course contents of ESP curriculum model for hospitality derived from the consensus of both educators and practitioners. The results revealed that two dimensions of ESP curriculum model for hospitality field constructed as well as nine courses contained in this study respectively. Also, it appears that Taiwan’s hospitality educators and practitioners should assist students/learners to strengthen English proficiency.

A stretchable organic digital information storage device has been developed, which potentially advances the development of future smart and digital stretchable electronic systems. The stretchable organic memory with a buckled structure was configured by a mechanically flexible and elastic graphene bottom electrode and polymer compound. The current–voltage curve of the wrinkled memory device demonstrated electrical bistability with typical write-once-read-many times memory features and a high ON/OFF current ratio (∼105). Even under repetitive stretching, the stretchable organic memory exhibited excellent electrical switching functions and memory effects. We believe the first proof-of-concept presentation of the stretchable organic nonvolatile memory may accelerate the development of information storage device in various stretchable electronic applications, such as stretchable display, wearable computer and artificial skin. Stretchable and foldable electronic devices are very attractive, not only for their practicality but also for their potential in as-yet-undeveloped applications, such as artificial electronic skin. Now, Yang-Fang Chen from the National Taiwan University and co-workers have constructed a stretchable organic memory device. Although a variety of flexible organic electronic devices have already been built, which include transistors or solar cells, building stretchable memory devices has remained a challenge. This is because they typically contain a brittle metal electrode, and their fabrication also involves processes — such as spin coating — that are incompatible with flexible substrates. The researchers circumvented these issues by buckling both a graphene, rather than metallic, electrode and the active memory layers over a pre-stretched poly(dimethylsiloxane) elastomer. When the pre-strain was released, the materials adopted a wrinkled structure that endowed them with flexibility. The resulting device showed good electrical switching behavior and memory effects after several stretch/release cycles. A stretchable wrinkled organic memory has been successfully demonstrated. The stretchable organic memory with a graphene bottom electrode possesses rippled structures. The stretchable organic memory exhibits excellent electrical switching behaviors and memory effects even under repetitive stretching. It is believed that this stretchable organic memory may be beneficial for digital information storage in future stretchable electronic systems.

An experimental investigation of the twodimensional(2-D) flow normal to a flat plate at low to medium Reynolds numbers (ranging from 25 to 393 based on the breadth of the plate) is described. Both horizontal and vertical soap film tunnels are used to set up a truly 2-D experiment. The flow in the soap film is very thin and is a close approximation to 2-D flow. Momentum defect measurements are used to obtain the time averaged mean drag coefficient, cl, experienced by a normal flat plate via laser Doppler velocimetry. It is found that cl = 2.1 for the current Re range. The present data agree well with available nominally 2-D experimental results from previously published papers which were obtained in traditional towing tank, wind tunnel and water tunnel experiments with high plate aspect ratios. This measurement implies that the intrinsic 3-D motions in the previously nominally 2-D experiments are not significant on cl and the computational fluid dynamics results from previously published papers which are reviewed have overestimated cl. Introduction Bluff body flows are by nature very complex. Inevitably they involve boundary layer, free shear layer and wake flows, all accompanied by associated instabilities and non-linear interactions with each other and with the bluff body itself. Bluff body wake flows have direct engineering significance. The alternate shedding of vorticies in the near wake, in the classical vortex street configuration, leads to large fluctuating pressure forces in a direction some cases can trigger failure. A normal flat plate is in many ways the simp* Associate Professor, Department of Mechanical Engineering , Member AIAA ** Graduate Research Assistant, Department of Mechanical Engineering Copyright O 1998 by the American Institute of Aeronautics and Astronautics Inc . All right reserved. lest possible bluff body, since it has geometrically fixed separation points, and since the interaction between the body and the near wake formation region is minimized. However, in comparison to the bulk of contemporary literature dealing with circular cylinder flows, very few results have been published for normal flat plates. Of the normal flat plate results which are available, typically Strouhal shedding frequency, force and/or pressure coefficients are presented only as time averaged mean quantities. Lisoski' has reviewed published experimental and computational results for time averaged mean drag coefficient, cT, and Strouhal number, St, of nomianlly 2-D noraml flat plates extensively. The main thing to note about the reviewed results is the large difference in cT between the experimental results( typically c7 = 2.0 ) and the 2-D numerical models( typically c7 = 3.2 ),which in some cases have a drag of almost twice the experimental values. There has been a tendency to think of these truly 2-D computer models as being wrong, and to modify them by various means so that their results conform with "2-D" experiments which are indeed threedimensional. As has been noted by Lisoski, "this is the wrong approach." He then went on investigating the intrinsic( small scale ) and extrinsic( large scale ) 3-D motions in the towing tank and water channel experiments. A 2-D vortex element numerical model developed by Chua was also used for comparison with his experimental results. It is shown that agreement between normally 2-D experimental and 2-D numerical-model results is good at early times, indicating the experiments are 2-D until the breakdown of the closed wake bubble following the initial accerlation. The approach of this paper is different. A truly 2-D experiment is conducted to have a direct comparison with the previously 2-D numerical results on cl. Freely suspended flowing soap films are used to set up the truly 2-D flows. These films, which have a thickness of the order of a micron, offer an excellent opportunity for studying hydrodynamics American Institute of Aeronautics and Astronautics Copyright© 1997, American Institute of Aeronautics and Astronautics, Inc.