286 research outputs found

    Characterization of different tannins for possible industrial resin production

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    Tannins are the fourth most abundant component in plant material after cellulose, hemicellulose, and lignin, and have received extensive attention due to their high content of phenolic and carboxyl groups. The earliest use of tannins can be traced back to the Neolithic Age for leather making. Although many researchers have tried to describe tannins in detail, the properties obtained from different sources by different analytical methods vary greatly. In order to tailor the commercial use of tannins, it is very important to characterize tannin samples before commercial applications. In this thesis, six kinds of tannins were extensively characterized with various methods to explore the differences between different industrial processed tannins, and their feasibility as a substitute for petroleum-derivative phenol in the production of resins. First, the physical properties of the tannins were determined, including pH, moisture content, ash content and elemental analysis. The elemental analysis was performed on crude tannins and tannin ash using SEM-EDS. In this thesis, DSC and TGA characterization of crude tannins were performed to provide thermogravimetric information. In addition, GPC and FT-IR methods were used to determine the molar mass and functional groups of tannins, respectively. Secondly, in order to investigate the composition of tannins in addition to moisture and ash content, ASE with six solvents of increasing polarity was used to sequentially extract the crude tannins, and the extracts were analyzed by SEC-MALS. Acid hydrolysis and methanolysis combined with GC analysis techniques were used to determine the composition of cellulose and non-cellulosic polysaccharides in crude tannins and short column GC combined with GC-MS was used for qualitative and quantitative analysis of the extracts. Finally, pyrolysis-GC MS and different NMR analysis techniques including 13C, HSQC and 31P NMR were used to determine the structure of the tannin molecules. The results show that the different methods described above can effectively characterize the obtained tannin samples and provide information for their possible industrial application

    Concomitant pulmonary and thyroid tumors identified by FDG PET/CT and immunohistochemical techniques

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    <p>Abstract</p> <p>Background</p> <p>The exact diagnosis of double primary papillary adenocarcinoma of thyroid and lung is even rarer, to our knowledge no report in the literature by [<sup>18</sup>F]-2-fluoro-2-deoxy-D-glucose-positron emission tomography/X-ray CT(FDG PET/CT) with surgical specimens immunohistochemistry(IHC). We report a patient with abnormal FDG PET/CT in thyroid and lung, this unusual presentation may lead to misdiagnosis without surgical specimens IHC.</p> <p>Case presentation</p> <p>A 56-year-old man with coughing three months. FDG PET/CT was performed, and resection specimens of lung and thyroid were detected by hematoxylin eosin staining (HE) and IHC. PET/CT: lung tumor SUVmax: 3.69, delay: 5.17; and thyroid tumor SUVmax 19.97. HE reveal papillary adenocarcinoma, but histological differentiation of primary pulmonary adenocarcinoma from metastatic adenocarcinoma is sometimes difficult because of their phenotypic similarities. So IHC was performed, the IHC of lung tumor: cytokeratin 20 (CK20)(-), thyroglobulin(Tg)(-), cytokeratin7(CK7)(+), thyroid transcription factor-1 (TTF-1)(+); thyroid tumor: CK7(+), TTF-1(+), thyroglobulin (+), CK20(-). Therefore, the final diagnosis was double primary adenocarcinomas of thyroid and lung.</p> <p>Conclusion</p> <p>FDG PET/CT has preliminary diagnostic capacity of multiple primary tumors; the final diagnosis should be adopted for specimens after tumor-specific markers IHC to obtain. Consequently, effective therapeutic approaches can be designed and conducted.</p

    An organosilane self-assembled monolayer incorporated into polymer solar cells enabling interfacial coherence to improve charge transport

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    The reproducible silylation of titanium oxide (TiO2) with small molecular (dichloromethyl) dimethylchlorosilane (DCS) as the cathode buffer layer was developed to improve electron extraction. Through incorporating the DCS capping layer into polymer solar cells (PSCs), the interfacial coherence of devices could be enhanced, leading to a shift in nanocrystallite size and a smaller internal charge transport resistance. Furthermore, a TiO2/DCS combined interfacial layer could serve as both an exciton dissociation center and a charge transfer channel, which results in a reduction in the energy barrier and electron loss, improving hole-blocking and surface-state passivation in the TiO2 interfacial layer. The Kelvin probe measurements demonstrate that the employment of the DCS nanolayer decreases conduction band energy of TiO2 via forming a dipole layer at the interface of TiO2 and the DCS nanolayer, which tunes the work-function of the device and ulteriorly enhances charge carrier transfer between the electrode and the active layer. As a result, the photocurrent and the fill factor of the PSCs are both increased, resulting in an increased power conversion efficiency (PCE) of 6.959%

    An organosilane self-assembled monolayer incorporated into polymer solar cells enabling interfacial coherence to improve charge transport

    Get PDF
    The reproducible silylation of titanium oxide (TiO2) with small molecular (dichloromethyl) dimethylchlorosilane (DCS) as the cathode buffer layer was developed to improve electron extraction. Through incorporating the DCS capping layer into polymer solar cells (PSCs), the interfacial coherence of devices could be enhanced, leading to a shift in nanocrystallite size and a smaller internal charge transport resistance. Furthermore, a TiO2/DCS combined interfacial layer could serve as both an exciton dissociation center and a charge transfer channel, which results in a reduction in the energy barrier and electron loss, improving hole-blocking and surface-state passivation in the TiO2 interfacial layer. The Kelvin probe measurements demonstrate that the employment of the DCS nanolayer decreases conduction band energy of TiO2 via forming a dipole layer at the interface of TiO2 and the DCS nanolayer, which tunes the work-function of the device and ulteriorly enhances charge carrier transfer between the electrode and the active layer. As a result, the photocurrent and the fill factor of the PSCs are both increased, resulting in an increased power conversion efficiency (PCE) of 6.959%

    When graph convolution meets double attention: online privacy disclosure detection with multi-label text classification

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    With the rise of Web 2.0 platforms such as online social media, people’s private information, such as their location, occupation and even family information, is often inadvertently disclosed through online discussions. Therefore, it is important to detect such unwanted privacy disclosures to help alert people affected and the online platform. In this paper, privacy disclosure detection is modeled as a multi-label text classification (MLTC) problem, and a new privacy disclosure detection model is proposed to construct an MLTC classifier for detecting online privacy disclosures. This classifier takes an online post as the input and outputs multiple labels, each reflecting a possible privacy disclosure. The proposed presentation method combines three different sources of information, the input text itself, the label-to-text correlation and the label-to-label correlation. A double-attention mechanism is used to combine the first two sources of information, and a graph convolutional network is employed to extract the third source of information that is then used to help fuse features extracted from the first two sources of information. Our extensive experimental results, obtained on a public dataset of privacy-disclosing posts on Twitter, demonstrated that our proposed privacy disclosure detection method significantly and consistently outperformed other state-of-the-art methods in terms of all key performance indicators

    Enhanced electron extraction capability of polymer solar cells \u3ci\u3evia\u3c/i\u3e modifying the cathode buffer layer with inorganic quantum dots

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    Enhanced performance of polymer solar cells (PSCs) based on the blend of poly[N-9 -hepta-decanyl- 2,7-carbazole-alt-5,5-(4\u27,7\u27-di-2-thienyl-2\u27,1\u27,3\u27-benzothiadiazole)] (PCDTBT):[6,6]-phenyl-C70-butyric acid methyl ester (PC71BM) is demonstrated by titanium dioxide (TiO2) interface modification via CuInS2/ZnS quantum dots (CZdots). Devices with a TiO2/CZdots composite buffer layer exhibit both a high shortcircuit current density (Jsc) and fill factor (FF), leading to a power conversion efficiency (PCE) up to 7.01%. The charge transport recombination mechanisms are investigated by an impedance behavior model, which indicates that TiO2 interfacial modification results in not only increasing the electron extraction but also reducing impedance. This study provides an important and beneficial approach to develop high efficiency PSCs

    Analysis of the Risk Factors for Elevated D-Dimer Level After Breast Cancer Surgery: A Multicenter Study Based on Nursing Follow-Up Data

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    D-dimer level is often used to assess the severity of trauma as well as the risk of thrombosis. This study investigated the risk factors for high postoperative D-dimer level. This study included a total of 2706 patients undergoing breast cancer surgery to examine the associations between various clinicopathological factors and variation in D-dimer levels. After adjusting for other factors, T stage, neoadjuvant chemotherapy, blood loss, surgery type, diabetes, and elevated leukocyte and neutrophil counts were found to be significant risk factors for D-dimer variation. This study identified several factors associated with elevated D-dimer levels and consequent thrombosis after breast cancer surgery, which may aid in the development of more precise preventive measures and interventions as well as serve as a reference for future research

    A Macromolecular Approach to Eradicate Multidrug Resistant Bacterial Infections while Mitigating Drug Resistance Onset

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    Polymyxins remain the last line treatment for multidrug-resistant (MDR) infections. As polymyxins resistance emerges, there is an urgent need to develop effective antimicrobial agents capable of mitigating MDR. Here, we report biodegradable guanidinium-functionalized polycarbonates with a distinctive mechanism that does not induce drug resistance. Unlike conventional antibiotics, repeated use of the polymers does not lead to drug resistance. Transcriptomic analysis of bacteria further supports development of resistance to antibiotics but not to the macromolecules after 30 treatments. Importantly, high in vivo treatment efficacy of the macromolecules is achieved in MDR A. baumannii-, E. coli-, K. pneumoniae-, methicillin-resistant S. aureus-, cecal ligation and puncture-induced polymicrobial peritonitis, and P. aeruginosa lung infection mouse models while remaining non-toxic (e.g., therapeutic index—ED50/LD50: 1473 for A. baumannii infection). These biodegradable synthetic macromolecules have been demonstrated to have broad spectrum in vivo antimicrobial activity, and have excellent potential as systemic antimicrobials against MDR infections

    Progress Towards the Miniaturization of an Ultrasonic Scalpel for Robotic Endoscopic Surgery Using Mn:PIN-PMN-PT High Performance Piezocrystals

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    Mn:PIN-PMN-PT piezocrystals are under consideration for potential use in miniaturised ultrasonic scalpels for robotic minimally-invasive surgery where small size and light weight may be advantageous. Electromechanical coupling coefficient k &gt; 0.9 for both [001] and [011] poled Mn:PIN-PMN-PT was calculated, confirming the well-recognized higher efficiency of this material when compared to standard piezoceramics. Novel transducer design strategies have been explored, and outcomes are discussed. The introduction of components with additional compliance in a standard d 31 mode transducer has been shown to drop the resonant frequency of the first longitudinal mode by more than 17%, with more than 75% improvement in tip/blade displacement. Results suggest that the combination of high performance piezocrystals with highly compliant components may be a useful route to follow to achieve our miniaturisation target
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