Influence of the apparatus on the intensity ratio of the measured Raman peaks.

We report an analytic result about the influence of the apparatus on the intensity ratio of the Raman peaks. This ratio of the Raman peak with the larger linewidth to the one with the smaller linewidth will increase with the increasing width of the instrument response function and the linewidth of the incident laser. For the applications of the empirical equations based on the intensity ratio of Raman peaks, the spectral resolution of the instrument should be indicated, and the fitting associated with a measured instrument response function is recommended.

Spatiotemporal transcriptomic atlas of mouse organogenesis using DNA nanoball-patterned arrays.

Spatially resolved transcriptomic technologies are promising tools to study complex biological processes such as mammalian embryogenesis. However, the imbalance between resolution, gene capture, and field of view of current methodologies precludes their systematic application to analyze relatively large and three-dimensional mid- and late-gestation embryos. Here, we combined DNA nanoball (DNB)-patterned arrays and in situ RNA capture to create spatial enhanced resolution omics-sequencing (Stereo-seq). We applied Stereo-seq to generate the mouse organogenesis spatiotemporal transcriptomic atlas (MOSTA), which maps with single-cell resolution and high sensitivity the kinetics and directionality of transcriptional variation during mouse organogenesis. We used this information to gain insight into the molecular basis of spatial cell heterogeneity and cell fate specification in developing tissues such as the dorsal midbrain. Our panoramic atlas will facilitate in-depth investigation of longstanding questions concerning normal and abnormal mammalian development.

Two-Dimensional TiVC Solid-Solution MXene as Surface-Enhanced Raman Scattering Substrate.

Two-dimensional (2D) MXenes are attractive candidates as surface-enhanced Raman scattering (SERS) substrates because of their metallic conductivity and abundant surface terminations. Herein, we report the facile synthesis of bimetallic solid-solution TiVC (MXene) and its application in SERS. The few-layered MXene nanosheets with high crystallinity were successfully prepared using a one-step chemical etching method without ultrasonic and organic solvent intercalation steps. SERS activity of the as-prepared MXene was investigated by fabricating free-standing TiVC film as the substrate. A SERS enhancement factor of 1012 and femtomolar-level detection limit were confirmed using rhodamine 6G as a model dye with 532 nm excitation. The fluorescent signal of the rhodamine 6G dye was effectively quenched, making the SERS spectrum clearly distinguishable. Furthermore, we demonstrate that the TiVC-analyte system with ultrahigh sensitivity is dominated by the chemical mechanism (CM) based on the experimental and simulation results. The abundant density of states near the Fermi level of the TiVC and the strong interaction between the TiVC and analyte promote the intermolecular charge transfer resonance in the TiVC-analyte complex, resulting in significant Raman enhancement. Additionally, several other probe molecules were used for SERS detection to further verify CM-based selectivity enhancement on the TiVC substrates. This work provides guidance for the facile synthesis of 2D MXene and its application in ultrasensitive SERS detection.

Novel hierarchical Sn3O4/BiOX (X = Cl, Br, I) p-n heterostructures with enhanced photocatalytic activity under simulated solar light irradiation.

Sn3O4/BiOX (X = Cl, Br, I), a series of p-n-heterojunction-based photocatalysts, were prepared by a combination of an ultrasonic-assisted precipitation-deposition method and hydrothermal method. The photodegradation of Rhodamine B among all the materials, under simulated solar light irradiation, was investigated in detail. The photocatalyst test showed that the novel composite, Sn3O4/BiOCl, was able to degrade 99% of Rhodamine B (RhB) and its intermediates in 9 minutes, which is faster than Sn3O4/BiOBr (21 min) and Sn3O4/BiOI (12 min). Moreover, the degradation rate of RhB for Sn3O4/BiOCl samples (Sn : Bi = 1/4) was the highest, about 99%, slightly higher than that of Sn3O4/BiOCl-1/8 (95%), which was significantly higher than those of Sn3O4/BiOCl-1/2 (78%), BiOCl (77%), P25 (62%) and Sn3O4 (16%) after nine minutes of irradiation under a xenon lamp. It can be inferred that when the bismuth/tin ratio was optimum, BiOCl enabled the formation of the enough space charge regions on the surface of Sn3O4, which promoted the separation of photogenerated electron-hole pairs. This implied that high-quality interfaces in the heterostructure catalysts play a key role in improving the photocatalytic performance. The enhanced photocatalytic performance can be attributed to the synergistic effects from two main factors: (1) the layered multi-stage structure increases the scattering of light on the catalyst surface, which proves to be beneficial in enhancing the absorption of the visible light; (2) the p-n heterojunctions between Sn3O4 and BiOX (X = Cl, Br, I) efficiently promote the separation of photogenerated carriers and accelerate the migration of photogenerated carriers. In addition, the results of the 'active species trapping' experiment illustrated that in the Sn3O4/BiOCl composite, holes contribute more to the high photocatalytic performance, while hydroxyl radicals show less importance to degrade RhB. Moreover, the photocatalytic mechanism was also discussed based on the investigation of reactive species and the band structure of Sn3O4/BiOCl.

Guidelines and recommendations on the clinical use of shear wave elastography for evaluating thyroid nodule1.

Ultrasound elastography has been introduced into clinical practice for a decade and arisen continuous increasing attention worldwide. Shear wave elastography (SWE) is a further extension of ultrasound elastography on the basis of strain elastography, providing a two-dimensional distribution map of tissue stiffness and quantitative measurement of the tissue stiffness in Young's modulus (kPa) and/or shear wave speed (m/s). The Society of Ultrasound in Medicine, Chinese Medical Association (CMA) has recently released a series of guidelines for the use of SWE, including the technique and principle of SWE, and use of SWE in liver fibrosis, breast, thyroid, and musculoskeletal system. Herein, a part of SWE in thyroid nodules is presented. In this guideline, the background, classification and technology of SWE, examination methods, diagnostic performance, prognosis evaluation, reproducibility, and limitations are discussed and recommendations are given. The recommendations are based on the published literatures with regard to SWE with different levels of evidence, particularly a mid-term result of the prospective multi-center clinical trial of SWE in thyroid, as well as the Society of Ultrasound in Medicine, CMA expert's consensus. The document provides an overall analysis of SWE in thyroid from clinical perspective, which aimed to provide recommendations to the clinicians with regard to the management of thyroid nodules by the assistance of SWE.

Chinese association of ultrasound in medicine and engineering, superficial organs and peripheral vessels committee expert consensus on clinical frequently asked questions in breast ultrasonography, June 2018.

Ultrasonography, the preferred imaging modality for breast diseases, has merits such as absence of radiation, high diagnostic accuracy, and convenience for follow-up, thus playing an important role in clinical diagnosis and management. The American College of Radiology (ACR) proposed Breast Imaging-Reporting and Data System (BI-RADS ) and has updated for several times. Gradually, the BI-RADS has been accepted and adopted by ultrasound physicians at all levels of hospitals in China, and it has played a certain role in improving the diagnostic level of breast ultrasound in China. In order to standardize breast ultrasound application and raise the status of ultrasound in clinical decision-making of breast diseases, based on the latest edition of ACR BI-RADS Atlas 2013, the committee has reached the "Expert Consensus on Clinical Frequently Asked Questions in Breast Ultrasonography"on a number of controversial Frequently Asked Questions (FAQs) in clinical practice (hereafter referred to as "Consensus"), and will be dedicated to updating the contents of the "Consensus", through further experience in clinical practice and the advent of new information from further studies. This consensus is only for reference purposes for medical personnel, and the processes outlined are not mandatory by law.

Enhanced UV-Visible Light Photocatalytic Activity by Constructing Appropriate Heterostructures between Mesopore TiO2 Nanospheres and Sn3O4 Nanoparticles.

Novel TiO2/Sn3O4 heterostructure photocatalysts were ingeniously synthesized via a scalable two-step method. The impressive photocatalytic abilities of the TiO2/Sn3O4 sphere nanocomposites were validated by the degradation test of methyl orange and •OH trapping photoluminescence experiments under ultraviolet (UV) and visible light irradiation, respectively. Especially under the visible light, the TiO2/Sn3O4 nanocomposites demonstrated a superb photocatalytic activity, with 81.2% of methyl orange (MO) decomposed at 30 min after irradiation, which greatly exceeded that of the P25 (13.4%), TiO2 (0.5%) and pure Sn3O4 (59.1%) nanostructures. This enhanced photocatalytic performance could be attributed to the mesopore induced by the monodispersed TiO2 cores that supply sufficient surface areas and accessibility to reactant molecules. This exquisite hetero-architecture facilitates extended UV-visible absorption and efficient photoexcited charge carrier separation.

Reduced Myocardial Reserve in Young X-Linked Muscular Dystrophy Mice Diagnosed by Two-Dimensional Strain Analysis Combined with Stress Echocardiography.

BACKGROUND: Early, sensitive, and reproducible evaluation of left ventricular function is imperative for the diagnosis of cardiac dysfunction in patients with Duchene muscular dystrophy. The aim of this study was to test the hypothesis that combining two-dimensional strain analysis with catecholamine stress could be a sensitive method for detecting early cardiac dysfunction. METHODS: Mdx (C57BL/10ScSn-Dmdmdx/J, a mouse model of DMD) and control (C57BL/10ScSn) mice were studied with conventional M-mode and high-frequency ultrasound-based two-dimensional speckle-tracking echocardiography using long- and short-axis images of the left ventricle at baseline and after intraperitoneal isoprenaline (ISO) administration (2 µg/g body weight). RESULTS: Conventional M-mode analysis showed no differences in left ventricular fractional shortening, wall thickness, or internal diameter at diastole between mdx and control mice before the age of 6 months. ISO increased left ventricular ejection fraction and fractional shortening to the same extent in mdx and control mice at young ages (3, 4, and 5 months). No differences in basal peak systolic strain (PSS) but increased SDs of times to PSS between young mdx and control mice were found. After ISO, PSS and percentile changes of PSS were significantly diminished in mdx mice compared with control mice at young ages. ISO increased the normalized maximum difference of times to PSS in young mdx mice but not in young control mice, suggesting that ISO reduces cardiac contractile synchrony in young mdx mice. CONCLUSIONS: This study suggests that catecholamine stress coupled with two-dimensional strain analysis is a feasible and sensitive approach for detecting early onset of cardiac dysfunction, which is instrumental for early diagnosis of cardiac dysfunction and early treatment.

Bonding and Anti-bonding Modes of Plasmon Coupling Effects in TiO2-Ag Core-shell Dimers.

Bonding and anti-bonding modes of plasmon coupling effects are numerically investigated in TiO2-Ag core-shell nano dimers. First, splitting phenomena of the coupled anti-bonding modes are observed under the longitudinal polarization when the distance between the monomers decreases to a certain level. Second, one of the split resonance modes is identified to be formed by the dipole anti-bonding mode of the monomers from charge density distribution patterns. Those split modes have similar redshift behaviors as the coupled dipole bonding modes in the same situations. Furthermore, the intensities of those anti-bonding modes weaken with decreasing distance between the monomers, because of the interaction of the induced dipole moment in the monomers and the charge distribution variation on the facing surfaces of the gap by the coulomb attraction. Other split bands are the higher-order mode (octupole-like or triakontadipole-like), which do not have obvious peak-shift behavior, and the intensities have very little attenuation with decreasing distance. Finally, the coupling of the bonding and anti-bonding modes under the longitudinal polarization is symmetric (bonding).

Synthesis of Nanocrystalline SnO2 Microspheres and Their Hydrogen Absorption Characteristics.

SnO2 solid microspheres and multilayered nanocrystalline SnO2 hollow microspheres (MHS-SnO2) have been successfully synthesized in the solvothermal environment by using different solvents. The morphology, structure and composition of the as-prepared products are characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) and X-ray diffraction (XRD). The growth mechanism of SnO2 solid microspheres and MHS-SnO2 are proposed and attributed to the viscosity of solvent. The studies on hydrogen absorption characteristics of SnO2 solid structure and MHS-SnO2 show an absorption capability of 0.50 wt.% and 0.92 wt.%, respectively.

Optical control of fluorescence through plasmonic eigenmode extinction.

We introduce the concept of optical control of the fluorescence yield of CdSe quantum dots through plasmon-induced structural changes in random semicontinuous nanostructured gold films. We demonstrate that the wavelength- and polarization dependent coupling between quantum dots and the semicontinuous films, and thus the fluorescent emission spectrum, can be controlled and significantly increased through the optical extinction of a selective band of eigenmodes in the films. This optical method of effecting controlled changes in the metal nanostructure allows for versatile functionality in a single sample and opens a pathway to in situ control over the fluorescence spectrum.

Effect of atomic percentage of Zn on the size and optical properties of porous ZnMn2O4 nanoparticles.

The porous ZnMn2O4 nanostructures have been synthesized by hydrothermal method by using Mn3O4 and Zn powder as precursors. The morphology of the nanoparticles could be tuned by changing the molar ratio of Zn in the reaction system. The final products have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, UV-visible spectroscopy and the florescence spectrometer. Room temperature photoluminescence investigation indicates that the nanostructures have strong band-gap emission at yellow and orange bands. Absorption properties of ZnMn2O4 nanostructures indicated that the band gap energy varied with change in the atomic percentage of Zn in hetaerolite ZnMn2O4. The mechanism of this peculiar optical property was analyzed.

Far-field plasmonic resonance enhanced nanoparticle image velocimetry within a microchannel.

In this paper, a novel far-field plasmonic resonance enhanced nanoparticle-seeded particle image velocimetry has been demonstrated to measure the velocity profile in a microchannel. Chemically synthesized silver nanoparticles have been used to seed the flow in the microchannel. By using discrete dipole approximation, plasmonic resonance enhanced light scattering has been calculated for spherical silver nanoparticles with diameters ranging from 15 to 200 nm. Optimum scattering wavelength is specified for the nanoparticles in two media: water and air. The diffraction-limited plasmonic resonance enhanced images of silver nanoparticles at different diameters have been recorded and analyzed. By using standard particle image velocimetry techniques, the velocity profile within the microchannel has been determined from the images.

Ultraviolet Extinction and Visible Transparency by Ivy Nanoparticles.

Though much research has been conducted for nanoparticles, naturally occurring nanoparticles have not yet been well explored for their diverse properties and potential applications. This paper reports the optical absorption and scattering properties of nanoparticles secreted by English ivy. Both experimental and theoretical studies have been conducted. Strong ultraviolet extinction and excellent visible transparency are observed, compared to the inorganic TiO(2) and ZnO nanoparticles at similar concentrations. The contributions of absorption and scattering to the total extinction are quantified by simulation of the Mie scattering theory.

Naturally occurring nanoparticles from English ivy: an alternative to metal-based nanoparticles for UV protection.

BACKGROUND: Over the last decade safety concerns have arisen about the use of metal-based nanoparticles in the cosmetics field. Metal-based nanoparticles have been linked to both environmental and animal toxicity in a variety of studies. Perhaps the greatest concern involves the large amounts of TiO2 nanoparticles that are used in commercial sunscreens. As an alternative to using these potentially hazardous metal-based nanoparticles, we have isolated organic nanoparticles from English ivy (Hedera helix). In this study, ivy nanoparticles were evaluated for their potential use in sunscreens based on four criteria: 1) ability to absorb and scatter ultraviolet light, 2) toxicity to mammalian cells, 3) biodegradability, and 4) potential for diffusion through skin. RESULTS: Purified ivy nanoparticles were first tested for their UV protective effects using a standard spectrophotometric assay. Next the cell toxicity of the ivy nanoparticles was compared to TiO2 nanoparticles using HeLa cells. The biodegradability of these nanoparticles was also determined through several digestion techniques. Finally, a mathematical model was developed to determine the potential for ivy nanoparticles to penetrate through human skin. The results indicated that the ivy nanoparticles were more efficient in blocking UV light, less toxic to mammalian cells, easily biodegradable, and had a limited potential to penetrate through human skin. When compared to TiO2 nanoparticles, the ivy nanoparticles showed decreased cell toxicity, and were easily degradable, indicating that they provided a safer alternative to these nanoparticles. CONCLUSIONS: With the data collected from this study, we have demonstrated the great potential of ivy nanoparticles as a sunscreen protective agent, and their increased safety over commonly used metal oxide nanoparticles.

Papillary thyroid carcinoma on sonography.

OBJECTIVE: The purpose of this study is to investigate the characteristics of papillary thyroid carcinomas (PTCs) on color duplex sonography (CDUS). METHODS: We retrospectively reviewed 115 nodules (104 patients) with PTC confirmed by pathology from February 1, 2005, to August 31, 2008. The size, border, calcification, echotexture, hemodynamics (peak systolic velocity and resistance index) of the thyroid nodules and cervical lymph nodes on CDUS were analyzed. RESULTS: There was a close relationship between the size of the nodule and the vascularity of the thyroid carcinoma (P=.000). Microcalcification increased the suspicion for malignancy of the thyroid nodule. A hypoechoic thyroid nodule with abundant internal vascularity, ill-defined border and microcalcification was highly suggested PTC. CONCLUSION: CDUS plays an important role in the early detection of PTC and cervical lymph node metastasis, which would provide surgeons with valuable information for planning surgical intervention. Mastering manifestations of PTC on CDUS will improve the accuracy in the diagnosis of PTC. CDUS-guided fine needle aspiration of the thyroid nodule is the standard in the diagnosis of thyroid carcinoma and metastasis pre- and postthyroidectomy.

Predicting endometrium receptivity with parameters of spiral artery blood flow.

In order To evaluate whether the parameters of spiral artery blood flow, as measured by transvaginal color Doppler, may be used to assess endometrium receptivity prior to embryo transfer (ET), a retrospective study of 94 infertile women who had undergone ART treatments with different outcomes (pregnant or nonpregnant) was done. Subendometrial blood flow was evaluated. The resistance index (RI), systolic/diastolic ratio (S/D) and pulsatility index (PI) were significantly lower in those who achieved pregnancy as compared with those who did not: 0.62+/-0.04 vs 0.68+/-0.04 (P<0.001), 2.66+/-0.33 vs 3.19+/-0.39 (P<0.01) and 1.15+/-0.17 vs 1.34+/-0.22 (P<0. 05), respectively. Furthermore, when RI>0. 2, PI>1. , and S/D>3. , no pregnancy occurred. These data suggest that the parameters of spiral artery blood flow could be used as a new assay in predicting endometrial receptivity before ET.

Broadband optical limiting and two-photon absorption properties of colloidal GaAs nanocrystals.

GaAs nanocrystals have been prepared by a mechanical ball milling technique. The optical limiting properties of colloidal ethanol suspensions of these crystals were investigated by use of a nanosecond optical parametric oscillator pumped by a Nd:YAG system. Not only at a wavelength of 1064 nm but also in the 490-670 nm visible region, colloidal GaAs nanocrystals with a concentration of 0.023 mg/mL exhibit strong optical limiting performance, which is better than that of C60 in toluene with the same linear transmittance at a wavelength of 532 nm. Two-photon absorption is regarded as the dominant mechanism for this technique, and the two-photon absorption coefficients of GaAs nanocrystals are estimated to be 5.6 and 21.1-37.0 cm/GW in the near-infrared and visible regions, respectively.

[Non-dilated coronary artery lesion and myocardial perfusion in children with Kawasaki disease: analysis of 43 cases].

OBJECTIVE: The study was designed to investigate the impact of non-dilated coronary artery wall lesion on myocardial perfusion. METHODS: Doppler tissue image (DTI) was used to measure regional ventricular wall motion in 43 Kawasaki children with non-dilated coronary arterial wall echocardiographic abnormalities (rough intima and arterial wall thickening) detected by two-dimensional echocardiography (2DE) at acute phase. A total of 31 cases who had both non-dilated coronary lesion and lowered ventricular wall motion velocity at subacute and convalescence phase underwent submaximal exercise single photon emitting computerized tomography (SPECT) for the evaluation of myocardial perfusion. RESULTS: In 43 cases of Kawasaki disease with non-dilated coronary arterial wall abnormalities, 36 cases (83.7%) still had such lesions at subacute phase and 32 (74.4%)at convalescence. At the same time, lowered regional ventricular wall motion (RVWM) was found in 34 cases at subacute phase and in 31 cases at convalescence. DTI and 2DE had a very good correlation in the detection of such abnormalities (chi(c)2 = 9.64, P < 0.01 in subacute period, and chi(c)2 = 7.14, P < 0.01 in convalescence). In 31 cases accepting SPECT, 17 were positive. A total of 22 ischemic regions were detected. Eighteen out of 22 cases having ischemic regions had abnormal RVWM on DTI. SPECT ischemic regions were significantly in accordance with lowered RVWM in ventricular septum and anterior wall (chi(c)2=5.07 and 7.48, P < 0.05 and P < 0.01, respectively) noted in DTI. CONCLUSION: Non-dilated coronary arterial wall abnormality is one of the forms of coronary artery wall lesions which could reduce myocardial flow perfusion. Its clinical significance is worthy of attention.