This study aims to utilize silicon carbide (SiC) powder and phenol-formaldehyde resin (PF) as the primary raw materials to prepare phenol-formaldehyde coated silicon carbide composite (PCSC) using a thermal coating method. Then, single-factor experiment and orthogonal experiment were used to optimize the process parameters of selective laser sintering (SLS). Finally, SiC precursors were formed using optimized process parameters with excellent density and dimensional accuracies. The results show that the best combination of process parameters is: laser power of 25 W, scanning speed of 1.7 m/s, scanning spacing of 0.12 mm and layer thickness of 0.16 mm.

Dialogue discourse parsing is a fundamental natural language processing task. It can benefit a series of conversation-related downstream tasks including dialogue summarization and emotion recognition in conversations. However, existing parsing approaches are constrained by predefined relation types, which can impede the adaptability of the parser for downstream tasks. To this end, we propose to introduce a task-aware paradigm to improve the versatility of the parser in this paper. Moreover, to alleviate error propagation and learning bias, we design a graph-based discourse parsing model termed DialogDP. Building upon the symmetrical property of matrix-embedded parsing graphs, we have developed an innovative self-supervised mechanism that leverages both bottom-up and top-down parsing strategies. This approach allows the parsing graphs to mutually regularize and enhance each other. Empirical studies on dialogue discourse parsing datasets and a downstream task demonstrate the effectiveness and flexibility of our framework.

Gadolinium oxysulfide (Gd2O2S, GOS) doped with rare earth elements was often used as imaging materials for X-Ray imaging equipment because of its excellent properties of absorbing incident X-rays and converting them into visible light. The flat-panel detector based on the GOS phosphor screen is the core imaging component of the digital radiography. In this paper, GOS slurry was prepared to form phosphor screen by tape casting, and the influence of slurry solvents and different additives on the rheological properties of the slurry was systematically studied. Based on the results of rheological properties, the optimal solid content of the slurry and the optimal addition range of the additives, like dispersants, binders and plasticizers, were determined. The solid content of the slurry is 70%, and the best amount of dispersant is 0.5%~1% of the powder mass. The optimized dosage of binder is 4.5%~7% of the powder mass, and the best plasticizer content is 1.0~1.5 times of the binder content. Then, the GOS fluorescent layer with smooth and flat surface, uniform and controllable thickness, and good bonding ability, was successfully prepared by tape casting the optimized slurry.

Mitochondria are dynamic organelles responsible for energy production and cell metabolism. Disorders in mitochondrial function impair tissue integrity and have been implicated in multiple human diseases. Rather than constrained in host cells, mitochondria were recently found to actively travel between cells through nanotubes or extracellular vesicles. Mitochondria transportation represents a key mechanism of intercellular communication implicated in metabolic homeostasis, immune response, and stress signaling. Here we reviewed recent progress in mitochondria transfer under physiological and pathological conditions. Specifically, tumor cells imported mitochondria from adjacent cells in the microenvironment which potentially modulated cancer progression. Intercellular mitochondria trafficking also inspired therapeutic intervention of human diseases with mitochondria transplantation. Artificial mitochondria, generated through mitochondria genome engineering or mitochondria-nucleus hybridization, further advanced our understanding of mitochondrial biology and its therapeutic potential. Innovative tools and animal models of mitochondria transplantation will assist the development of new therapies for mitochondrial dysfunction-related diseases.

Background Acute myocardial infarction (MI) is the primary factor leading to cardiovascular diseases, which are the main causes of morbidity and mortality in developed countries. Mesenchymal stem cell (MSC)-derived exosomes have been reported to improve heart function after MI; however, the molecular mechanisms responsible for this are unknown. In vivo imaging can reveal the trafficking process and in vivo biodistribution of exosomes, which may provide an insight into the communication mechanisms and pharmacokinetics of exosomes. Methods Glucose modified gold nanoparticles were used to label MSC-derived exosomes, aimed at minimizing membrane damage and maintaining the integrity of the exosomes. After labeling, the exosomes were visualized by in vivo computed tomography (CT) imaging to determine the biodistribution at 4 and 24 h after injection into a MI mouse model. Results MSC-derived exosomes were successfully labeled by glucose modified gold nanoparticles and CT imaging of these labeled exosomes indicated that MSC-Exo remained in the MI area for up to 24 h after intramyocardial injection. Additionally, few MSC-Exo were observed in some other organs, particularly the liver, spleen, and kidney. Conclusions A gentle method was used for loading GNPs into exosomes, and their successful labeling without causing aggregation was verified. In vivo CT imaging revealed the retention of MSC-Exo in the MI area, indicating their usefulness for improving heart function after infarction.

BACKGROUND Manual or machine-based analysis of chest radiographs needs the images acquired with technical adequacy. Currently, the equidistance between the medial end of clavicles and the center of spinous processes serves as the only criterion to assess whether a frontal PA chest radiograph is taken with any rotation. However, this measurement is normally difficult to implement because there exists overlapping of anatomies within the region. Moreover, there is no way available to predict exact rotating angles even the distances were correctly measured from PA chest radiographs. OBJECTIVE To quantitatively assess positioning adequacy of PA chest examination, this study proposes and investigates a new method to estimate rotation angles from asymmetric projection of thoracic cage on radiographs. METHOD By looking into the process of radiographic projection, generalized expressions have been established to correlate rotating angles of thorax with projection difference of left and right sides of thoracic cage. A trunk phantom with different positioning angles is employed to acquire radiographs as standard reference to verify the theoretical expressions. RESULTS The angles estimated from asymmetric projections of thoracic cage yield good agreement with those actual rotated angles, and an approximate linear relationship exists between rotation angle and asymmetric projection of thoracic cage. Under the experimental projection settings, every degree of rotation corresponds to the width difference of two sides of thoracic cage around 13-14 pixels. CONCLUSION The proposed new method may be used to quantify rotating angles of chest and assess image quality for thoracic radiographic examination.

We aimed to investigate the role of the miR‐29b and its effect on TGF‐β3 pathway in vascular and valvular calcification in a rat model of calcific aortic valve diseases (CAVD). A rat model of CAVD was established by administration of warfarin plus vitamin K. The expression levels of miR‐29b, osteogenic markers and other genes were determined by qRT‐PCR, Western blot and/or immunofluorescence and immunohistochemistry. The calcium content and alkaline phosphatase (ALP) activity were measured. The calcium content, ALP activity and osteogenic markers levels in calcified aorta and aortic valve were augmented compared to controls. The expression of miR‐29b, p‐Smad3, and Wnt3 and β‐catenin was significantly up‐regulated, whereas TGF‐β3 was markedly down‐regulated. However, compared with the CAVD model group, the calcium content and ALP activity in rats treated with antagomiR‐29b were significantly decreased, and antagomiR‐29b administration reversed the effects of CAVD model on the expression of miR‐29b and osteogenic markers. Inhibition of miR‐29b in CAVD rats prevented from vascular and valvular calcification and induced TGF‐β3 expression, suggesting that the miR‐29b/TGF‐β3 axis may play a regulatory role in the pathogenesis of vascular and valvular calcification and could play a significant role in the treatment of CAVD and other cardiovascular diseases.

Gd 2 O 2 S: Tb (GOS) phosphor screen has been widely used in digital X-ray imaging, and so far, numerous studies have been focused on the doping ions to improve the luminescence performance of the GOS phosphors. GOS: Tb, Dy phosphors were synthesized by the solid-state reaction process, and their phase composition, particle size, morphology and luminescence properties were characterized. The results showed that co-doping Dy 3+ can promote the luminescence and the optimal doping concentration of Dy3 + ions were about 0.2%, however concentration quenching will occur when the doping concentration exceeded 0.5%. Ta 5+ ion was also studied in the GOS: Tb and GOS: Tb; Dy phosphors prepared by the same method. The results showed that when the Ta 5+ co-doping concentration was 100ppm, the strongest emitted light intensity would be obtained for both phosphors. The photoluminescence spectra revealed a different influencing mechanism of Ta 5+ ion comparing to Dy 3+ , which is by a strong energy transfer between Dy 3+ and Tb 3+ .

Gd2O2S:Tb (GOS) phosphor screen, generally with a multilayer structure, has been widely used in digital X-ray imaging. GOS phosphor screen is fabricated via a slip casting route, which is an effective method to obtain multilayer composites with good strength. The GOS slurry was prepared using the menhaden oil, polyvinyl butyral and PEG-400 as dispersant, binder and plasticizer, respectively, and slip casted on a support layer. After the GOS scintillation layer is formed, a transparent polyethylene terephthalate film is covered on it as a protective layer. The X-ray excited emission spectra of the obtained GOS phosphor screen is well match to the spectral response of a-Si:H photodiode, and the spatial resolution was close to 3.7 LP/mm, which could meet the request of the commercial application.

Crystallized Gd-2(OH)(4)SO4 center dot nH(2)O precursor was synthesized in hot water bath using oxide powders and concentrated sulfuric acid as raw materials. Calcining the precursor in air produced the intermediate product Gd2O2SO4 and Gd2O2S powders with high phase purity was obtained by hydrogen reduction. The Gd2O2S powders showed layered structure and severe agglomeration with S-BET = 6.321 m(2)/g. Using this powders, a two-step sintering method comprised of pre-sintering in vacuum and hot isostatic pressing post-treatment was introduced for the fabrication of Gd2O2S:Tb ceramics. The relative density increased from 95.7% in pre-sintered body to 99.2% in final ceramics. Densification processes and chemical homogeneity of the ceramics were discussed. Photoluminescence and X-ray excited luminescence of the final ceramics demonstrated a bright green emission centered at 545 nm due to the D-5(4)-F-7(5) transition of Tb3+.

Recently, a variety of nanoparticles have been widely used as imaging agents or carriers for the diagnosis and therapy of lung cancer. However, their poor imaging effect, high toxicity, pro-inflammatory effect and ineffective treatment are still a great challenge. In this work, we reported a novel kind of BiOI@CuS nanoparticle to achieve safe and effective therapy of lung cancer by co-loading hydrochloric acid doxorubicin (DOX) and aspirin phenacetin and caffeine (APC). The nanoparticles can effectively relieve inflammatory reactions induced by photo-thermal therapy (PTT). In vitro and in vivo assays showed that DOX/APC co-loaded BiOI@CuS exhibited an effective chemo-photothermal comprehensive therapy effect and good CT imaging capability. Consequently, this multifunctional nanosystem provides a versatile and promising platform in the imaging and treatment of lung cancer in further applications.

以通过PE100级认证的管材专用高密度聚乙烯(牌号为TUB121N3000)为基体,紫外光老化和热氧老化时间为核心评价指标,开发出性能优异的橙色管材专用PE100级树脂.结果表明:橙色母料2544或2029B用量为最小单位用量的2倍,受阻胺光稳定剂、紫外光吸收剂、复合抗氧剂质量比为2:3:4时,制备的橙色管材专用PE100级树脂的氧化诱导时间大于30 min,颜料分散级别小于2级,紫外光老化2000 h后色差小于3,烘箱老化后断裂标称应变保留率大于50％.

This paper focuses on the preparation of mix ingredients through White &Black routine or by mixing recycled materials during pipe production.The availability,stability,adding amount of tracer in polyethylene(PE)100 tube specialty TUB121N3000B were investigated in laboratory by use of X-ray fluorescence spectrometer (XRF) and handheld detector,based on which the industrial production of anti-fake TUB121N3000B was realized.The test results show that the tracer can be used to distinguish the mix materials.The results obtained from XRF and handheld detector are identical to theoretical values.The deviation of XRF ranges from 1.0 to 2.0 μg/g and that of handheld detector of 4.0-8.0 μg/g.The tracer suffers less loss during repeated extrusion,showing its stability.XRF can be used for the quantification of the mix ingredients in mix material and the handheld detector for qualification only.

采用固相反应法按式Mg3(Si1-xCex)2O7(x=0.2,0.3,0.4和0.5)制备了MgO-SiO2-CeO2系列微波介质陶瓷材料,研究了不同组分体系的相组成与结构、微观结构与微波介电性能之间的影响关系.结果显示:MgO-SiO2-CeO2体系在研究组分范围内的晶相主要由正交相的Mg2SiO4与立方相的CeO2组成;其中,当x=0.5时出现了少量的未知相;经EDS分析可知,该未知相是由Mg、Si、Ce和O元素组成的新相;随着x值的增加,体系εr和τf值在1350～1600℃烧结温度下的变化不明显,而体系的Q×f值则呈先降后升趋势.此外,尽管体系并未能确定形成RP相层状结构,但其研究结果仍对探索新型RP相微波介质材料具有借鉴作用.

Sm2O3-Nd2O3-MgO-CeO2 ceramic systems of the form Sm1-xNdx(Mg0.5Ce0.5)03 (0.0 <= x <= 1.0) were synthesized by a conventional solid-state reaction method, and the phase structural characteristics, microstructures, sintering behaviors and microwave dielectric properties were investigated systematically. X-ray diffraction analyses revealed that a cubic fluorite-type structure with Fm-3m (225) space group was identified as the main crystalline phase in the composition range of x=0.0-1.0, while some secondary phases were also detected in all the Sm1-xNdx(Mg0.5Ce0.5)O-3 samples. The phase structural characteristics of Sm2O3-Nd2O3-MgO-CeO2 quaternary ceramic systems were significantly affected by a certain amount of Mg2+ ion volatilization, detected by the typical EDS data. Additionally, both an example of EDS analysis in the second phases regions and some details of the diffraction peaks implied that the unknown phases were mainly composed of MgO phase. Furthermore, for the microwave characteristics, the relative permittivity (epsilon(r)) was closely related to the dense degree and phase compositions, and also, the quality factor (Q x f) had been strongly depended on the compactness and lattice defects in these investigated ceramics. Wherein, after sintering at 1450 degrees C for 4 h, the x = 0.0 sample demonstrated the excellent microwave dielectric performance: epsilon(r) similar to 16.6, Q x f 111,280 GHz (at 7.938 GHz) and tau(f) similar to -56.7 ppm/C. These results also indicated that the Ce(1-x)Ln(x)O(2-delta) (Ln=Sm and Nd) solid solutions could be a good candidate for dielectric resonators, filters and other microwave electronic device applications. (C) 2017 Elsevier B.V. All rights reserved.

This article reviewed the research progress of the impact of doping on the microwave dielectric loss of Al2O3 ceramics,generalized the impact factors of the microwave dielectric loss of Al2O3 ceramics,focused on the influence of dopants with different valence states on the microwave dielectric loss of Al2O3 ceramics.In the final of the article some expectations on the future development were proposed,which can provide some profitable references for improving the microwave dielectric loss of Al2O3 ceramics.

Novel Eu3+ doped mayenite glass phosphors with Eu element homogeneously doped and high transparency were successfully synthesized by aerodynamic levitation method. The transmittance reached as high as 88% from the visible light up to 6µm in the mid-infrared wavelength. Under the excitation of 254nm (charge transfer), 393nm (Eu3+, 7F0→5L6 transition) and 464nm (Eu3+, 7F0→5D2 transition), glass phosphors emitted strong red luminescence with 615nm (5D0→7F2 transition) predominant in the emission spectra. Differences of decay lifetime in excitation wavelengths and Eu dopant concentrations could be ascribed to the non-radiation relaxation process and luminescent concentration before the quenching effect. Furthermore, Eu doped mayenite glass could also emit red light at 615nm (5D0→7F2 transition) under the X-ray excitation. Therefore, the high transparent C12A7: Eu glass phosphors could be promising candidates for solid state lighting, X-ray radiation detection, and even transparent displaying in the visible and mid-infrared ranges.

In this study, translucent CeF3 ceramics was firstly fabricated by hot‐pressing, aiming to develop an economical, radiation hard scintillation material. After sintering at 950°C and pressure exertion of 300MPa for 2 h, a transmittance of 10–25% was achieved in the visible region, through a thickness of 0.75 mm. Microstructure investigations indicated the average grain size was around 42.7 μm, with no obvious pores observed on the fracture surface. The X‐ray luminescence spectra, decay time, and thermoluminescence spectra were measured, and the results of the ceramics were similar to its corresponding single crystals, which proved it to be a promising scintillation material.