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Background: Hyperperfusion syndrome (HPS) following carotid angioplasty with stenting (CAS) is associated with significant morbidity and mortality. At present, there are no reliable parameters to predict HPS. The aim of this study was to clarify whether perfusion computed tomography (CT) is a feasible and reliable tool in predicting HPS after CAS. Methodology/Principal Findings: We performed a retrospective case-control study of 54 patients (11 HPS patients and 43 non-HPS) with unilateral severe stenosis of the carotid artery who underwent CAS. We compared the prevalence of vascular risk factors and perfusion CT parameters including regional cerebral blood volume (rCBV), regional cerebral blood flow (rCBF), and time to peak (TTP) within seven days prior to CAS. Demographic information, risk factors for atherosclerosis, and perfusion CT parameters were evaluated by multivariable logistic regression analysis. The rCBV index was calculated as [(ipsilateral rCBV - contralateral rCBV)/contralateral rCBV], and indices of rCBF and TTP were similarly calculated. We found that eleven patients had HPS, including five with intracranial hemorrhages (ICHs) of whom three died. After a comparison with non-HPS control subjects, independent predictors of HPS included the severity of ipsilateral carotid artery stenosis, 3- hour mean systolic blood pressure (3 h SBP) after CAS, pre-stenting rCBV index .0.15 and TTP index .0.22. Conclusions/Significance: The combination of severe ipsilateral carotid stenosis, 3 h SBP after CAS, rCBV index and TTP index provides a potential screening tool for predicting HPS in patients with unilateral carotid stenosis receiving CAS. In addition, adequate management of post-stenting blood pressure is the most important treatable factor in preventing HPS in these high risk patients. [ABSTRACT FROM AUTHOR]

At the National Synchrotron Radiation Research Center (NSRRC), which operates a 1.5 GeV storage ring, a dedicated small-angle X-ray scattering (SAXS) beamline has been installed with an in-achromat superconducting wiggler insertion device of peak magnetic field 3.1 T. The vertical beam divergence from the X-ray source is reduced significantly by a collimating mirror. Subsequently the beam is selectively monochromated by a double Si(111) crystal monochromator with high energy resolution (ΔE/E ≃ 2 x 10-4) in the energy range 5-23 keV, or by a double Mo/B4C multilayer mono- chromator for 10-30 times higher flux (∼1011 photons s-1) in the 6-15 keV range. These two monochromators are incorporated into one rotating cradle for fast exchange. The monochromated beam is focused by a toroidal mirror with 1:1 focusing for a small beam divergence and a beam size of ∼0.9 mm x 0.3 mm (horizontal x vertical) at the focus point located 26.5 m from the radiation source. A plane mirror installed after the toroidal mirror is selectively used to deflect the beam downwards for grazing-incidence SAXS (GISAXS) from liquid surfaces. Two online beam-position monitors separated by 8 m provide an efficient feedback control for an overall beam-position stability in the 10 μm range. The beam features measured, including the flux density, energy resolution, size and divergence, are consistent with those calculated using the ray-tracing program SHADOW. With the deflectable beam of relatively high energy resolution and high flux, the new beamline meets the requirements for a wide range of SAXS applications, including anomalous SAXS for multiphase nanoparticles (e.g. semiconductor core-shell quantum dots) and GISAXS from liquid surfaces. [ABSTRACT FROM AUTHOR]

Using a superconducting-wavelength-shifter X-ray source with a photon flux density of 1011–1013 photons s−1 mrad−1 (0.1% bandwidth)−1 (200 mA)−1 in the energy range 5–35 keV, three hard X-ray beamlines, BL01A, BL01B and BL01C, have been designed and constructed at the 1.5 GeV storage ring of the National Synchrotron Radiation Research Center (NSRRC). These have been designed for structure-related research using X-ray imaging, absorption, scattering and diffraction. The branch beamline BL01A, which has an unmonochromatized beam, is suitable for phase-contrast X-ray imaging with a spatial resolution of 1 µm and an imaging efficiency of one frame per 10 ms. The main beamline BL01B has 1:1 beam focusing and a medium energy resolution of ∼10−3. It has been designed for small-angle X-ray scattering and transmission X-ray microscopy, used, respectively, in anomalous scattering and nanophase-contrast imaging with 30 nm spatial resolution. Finally, the branch beamline BL01C, which features collimating and focusing mirrors and a double-crystal monochromator for a high energy resolution of ∼10−4, has been designed for X-ray absorption spectroscopy and high-resolution powder X-ray diffraction. These instruments, providing complementary tools for studying multiphase structures, have opened up a new research trend of integrated structural study at the NSRRC, especially in biology and materials. Examples illustrating the performances of the beamlines and the instruments installed are presented. [ABSTRACT FROM AUTHOR]

In this work, the excimer-laser-induced crystallization of amorphous silicon (a-Si) films was investigated numerically and experimentally. The basic structure is an a-Si film on a glass substrate. The control parameters are the laser intensity and the pulse number. The effects of SiO2 and Si3N4 layers located between the Si film and glass substrate were also studied. In the microstructure analysis of the laser-irradiated area, the critical fluences (full-melt threshold, FMT) between the partial melting and complete melting regimes can be found by applying scanning electron microscopy. An efficient two-dimensional numerical model is carried out to predict the critical fluences (FMT) and the transient temperature distribution during the laser processing. From the analysis of temperature responses, the FMT obtained from the simulation results of the proposed model agree fairly well with those from the experimental data reported in the literature and acquired in this research. [ABSTRACT FROM AUTHOR]

Abstract: A method to achieve wavelength tunability and single-longitudinal-mode oscillation in an S-band erbium-doped fiber (EDF) ring laser is proposed and demonstrated. A saturable-absorber-based autotracking filter consisting of an unpumped EDF and an optical reflector is utilized to provide fine mode restriction and guarantee the single-frequency operation. The performance of output power of larger than 1dBm, power stability of smaller than 0.02dB, wavelength variation of less than 0.01nm and side-mode suppression ratio of larger than 31dB has been experimentally demonstrated for this single-frequency fiber laser operating from 1482 to 1512nm. [Copyright &y& Elsevier]

Abstract: A stable and tunable S-band erbium-doped fiber (EDF) double-ring laser has been proposed and experimentally demonstrated. Based on the double-ring configuration, the EDF ring laser exhibits more stable output wavelengths and powers than those of the single-ring. Wide tunable range of 1484–1518nm, the side-mode suppression ratio (SMSR) of larger than 44.7dB/0.05nm and the output power of larger than −2.2dBm over the operation range of 1484–1510nm have been retrieved. [Copyright &y& Elsevier]

Abstract: A forward optical feedback technique for gain-clamping erbium-doped waveguide amplifier has been proposed and experimentally investigated. Three different saturated tones are selected in this proposed structure over the operation range from 1530 to 1550 nm to realize the amplification behaviors. Therefore, a dynamic range of input signal power from −9 to −40 dBm at 1552 nm is obtained when different power level and lasing position of the saturated tone are applied. In addition, the gain clamping performance has also been investigated experimentally under different operation conditions such as the lasing wavelength, the cavity loss and the input signal wavelength. [Copyright &y& Elsevier]

The incidence of ischemic stroke (IS) is higher in nephrotic syndrome (NS) patients compared to general population. However, there is limited information on the specific characteristics to stroke patients with NS. In this study, we aimed to examine the clinical manifestations of acute IS in a large group of NS patients, comparing to those without NS. We conducted a retrospective cohort study to compare the clinical presentations of acute IS in patients with and without NS. This study was a multi-institutional study and used data from Chang Gung Research Database of Taiwan from 1 January 2001, to 31 December 2017. A total of 233 IS patients with NS and 1358 IS patients without NS were enrolled. The median age of participants was 68 (range: 59-79) years. The risk of dependent functional status (modified Rankin Scale score≤3) after IS was higher in NS patients compared to those without NS (Odd ratio (OR) 4.02, 95% confidence interval (CI) 2.39 to 6.76, p < 0.001), particularly in stroke subtypes as small-artery occlusion (OR 8.02, 95% CI 3.94 to 16.32, p < 0.001), and stroke of undetermined etiology (OR 2.47, CI 1.06 to 5.76, p = 037). The risks of mortality or stroke recurrence within 30 days were similar between the two groups for all stroke subtypes. In conclusion, NS was associated with a higher risk of functional dependence following IS. Intensive treatment and rehabilitation should be considered for IS patients with NS. [ABSTRACT FROM AUTHOR]

Band selection (BS) is one of the important topics in hyperspectral image (HSI) processing. Many types of BS algorithms were proposed in the last decade. However, most of them were designed for off-line use. They can only be used with pre-collected data, and are sometimes ineffective for applications that require timeliness, such as disaster prevention or target detection. This paper proposes an online BS method that allows us obtain instant BS results in a progressive manner during HSI data transmission, which is carried out under band-interleaved-by-sample/pixel (BIS/BIP) format. Such a revolutionary method is called progressive sample processing of band selection (PSP-BS). In PSP-BS, BS can be done recursively pixel by pixel, so that the instantaneous BS can be achieved without waiting for all the pixels of an image. To develop a PSP-BS algorithm, we proposed PSP-OMPBS, which adopted the recursive version of a self-sparse regression BS method (OMPBS) as a native algorithm. The experiments conducted on two real hyperspectral images demonstrate that PSP-OMPBS can progressively output the BS with extremely low computing time. In addition, the convergence of BS results during transmission can be further accelerated by using a pre-defined pixel transmission sequence. Such a significant advantage not only allows BS to be done in a real-time manner for the future satellite data downlink, but also determines the BS results in advance, without waiting to receive every pixel of an image. [ABSTRACT FROM AUTHOR]

Digital signal processing (DSP) with both linear equalization and nonlinear compensations are studied in this paper for the single-carrier 400G system based on 65-GBaud 16-quadrature amplitude modulation (QAM) signals. The 16-QAM signals are generated and pre-processed with pre-equalization (Pre-EQ) and Look-up-Table (LUT) based pre-distortion (Pre-DT) at the transmitter (Tx)-side. The implementation principle of training-based equalization and pre-distortion are presented here in this paper with experimental studies. At the receiver (Rx)-side, fiber-nonlinearity compensation based on digital backward propagation (DBP) are also utilized to further improve the transmission performances. With joint LUT-based Pre-DT and DBP-based post-compensation to mitigate the opto-electronic components and fiber nonlinearity impairments, we demonstrate the unrepeatered transmission of 1.6Tb/s based on 4-lane 400G single-carrier PDM-16QAM over 205-km SSMF without distributed amplifier. [ABSTRACT FROM AUTHOR]

Background: To investigate if initial blood pressure (BP) on admission is associated with stroke severity and predictive of admission costs and one-year-outcome in acute ischemic (IS) and hemorrhagic stroke (HS).Methods: This is a single-center retrospective cohort study. Stroke patients admitted within 3 days after onset between January 1st and December 31st in 2009 were recruited. The initial BP on admission was subdivided into high (systolic BP ≥ 211 mmHg or diastolic BP ≥ 111 mmHg), medium (systolic BP 111-210 mmHg or diastolic BP 71-110 mmHg), and low (systolic BP ≤ 110 mmHg or diastolic BP ≤ 70 mmHg) groups and further subgrouped with 25 mmHg difference in systole and 10 mmHg difference in diastole for the correlation analysis with demographics, admission cost and one-year modified Rankin scale (mRS).Results: In 1173 IS patients (mean age: 67.8 ± 12.8 years old, 61.4% male), low diastolic BP group had higher frequency of heart disease (p =0.001), dehydration (p =0.03) and lower hemoglobin level (p <0.001). The extremely high and low systolic BP subgroups had worse National Institutes of Health Stroke Scale (NIHSS) score (p =0.03), higher admission cost (p <0.001), and worse one-year mRS (p =0.03), while extremely high and low diastolic BP subgroups had higher admission cost (p <0.01). In 282 HS patients (mean age: 62.4 ± 15.4 years old, 60.6% male), both low systolic and diastolic BP groups had lower hemoglobin level (systole: p =0.05; diastole: p <0.001). The extremely high and low BP subgroups had worse NIHSS score (p =0.01 and p <0.001, respectively), worse one-year mRS (p =0.002 and p =0.001, respectively), and higher admission cost (diastole: p <0.002).Conclusions: Stroke patients with extremely high and low BP on admission have not only worse stroke severity but also higher admission cost and/or worse one-year outcome. In those patients with low BP, low admission hemoglobin might be a contributing factor. [ABSTRACT FROM AUTHOR]

Abstract: A simple multi-band QPSK signal transmission scheme, constructed by using an optical remote up-conversion technique and a Schottky diode RF detector, is theoretically analyzed and experimentally implemented in a 60-GHz millimeter wave (mm-wave) radio over fiber (RoF) system, for the first time. There is no need for complex system architecture or any expensive high-frequency clock source in our scheme. Simulation results show that our scheme is highly tolerant to fiber dispersion, compared with the conventional 60GHz multi-band RoF system. In the experimental demonstration, successful delivery of QPSK signals at two 60-GHz sub-bands is achieved over 50-km fiber and 4-m wireless distance. [Copyright &y& Elsevier]

At the National Synchrotron Radiation Research Center, a small/wide-angle X-ray scattering (SAXS/WAXS) instrument has been installed at the BL23A beamline with a superconducting wiggler insertion device. This beamline is equipped with double Si(111) crystal and double Mo/B4C multilayer monochromators, and an Si-based plane mirror that can selectively deflect the beam downwards for grazing-incidence SAXS (GISAXS) studies of air-liquid or liquid-liquid interfaces. The SAXS/WAXS instrument, situated in an experimental hutch, comprises collimation, sample and post-sample stages. Pinholes and slits have been incorporated into the beam collimation system spanning a distance of ∼5 m. The sample stage can accommodate various sample geometries for air-liquid interfaces, thin films, and solution and solid samples. The post-sample section consists of a 1 m WAXS section with two linear gas detectors, a vacuum bellows (1-4 m), a two-beamstop system and the SAXS detector system, all situated on a motorized optical bench for motion in six degrees of freedom. In particular, the vacuum bellows of a large inner diameter (260 mm) provides continuous changes of the sample-to-detector distance under vacuum. Synchronized SAXS and WAXS measurements are realized via a data-acquisition protocol that can integrate the two linear gas detectors for WAXS and the area detector for SAXS (gas type or Marl65 CCD); the protocol also incorporates sample changing and temperature control for programmable data collection. The performance of the instrument is illustrated via several different measurements, including (1) simultaneous SAXS/WAXS and differential scanning calorimetry for polymer crystallization, (2) structural evolution with a large ordering spacing of ∼250 nm in a supramolecular complex, (3) SAXS for polymer blends under in situ drawing, (4) SAXS and anomalous SAXS for unilamellar lipid vesicles and metalloprotein solutions, (5) anomalous GISAXS for oriented membranes of Br-labeled lipids embedded with peptides, and (6) GISAXS for silicate films formed in situ at the air-water interface. [ABSTRACT FROM AUTHOR]

Background and Purpose: The purpose of the present study was to assess whether the direction of flow via the circle of Willis (CoW) changed after stenting for severe internal carotid artery (ICA) stenosis. Methods: 65 patients (38 men, mean age 63.2 ± 8.4 years, range 44–82) with a symptomatic ICA occlusion were investigated. Magnetic resonance angiography was performed prior to and 1 week after carotid artery stenting (CAS). The pattern in the CoW was assessed. Results: One third of the subjects (35.38%) had a significantly altered flow pattern in the CoW after unilateral CAS, including blocked ipsilateral A1 segment collateral (n = 4), blocked contralateral A1 segment collateral (n = 5), blocked ipsilateral posterior communicating artery (PCoA) segment collateral (n = 4), blocked ipsilateral A1 segment and P1 segment collateral (n = 1), opening of ipsilateral A1 segment collateral (n = 5), opening of ipsilateral PCoA segment collateral (n = 3) and opening of ipsilateral P1 segment collateral (n = 1). Conclusions: CoW segmental hypoplasia is not a static feature. Willisian collateralization with recruitment of the CoW segment (A1, P1 and PCoA) may be blocked after CAS. CAS also leads to the opening of new willisian collateralization, either for relief of reperfusion pressure or for other hypoperfused areas. Copyright © 2009 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Abstract: A multiwavelength fiber ring laser that is based on an S-band erbium-doped fiber amplifier (EDFA) and a semiconductor optical amplifier (SOA) is developed. An optical switch is used to switch the multiwavelength fiber laser between S-band and L-band. This fiber laser can stably lase seven wavelengths in the S-band or 28 wavelengths in the L-band. Additionally, the lasing wavelengths with a signal-to-noise ratio of over 33dB and a wavelength spacing of 100GHz are demonstrated experimentally. The average powers of the lasing wavelength in the S-band and the L-band are −7.53 and −12.15dBm, respectively. [Copyright &y& Elsevier]