6,020 research outputs found

    Fine-grained sketch-based image retrieval by matching deformable part models

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    (c) 2014. The copyright of this document resides with its authors. It may be distributed unchanged freely in print or electronic forms.Ā© 2014. The copyright of this document resides with its authors. An important characteristic of sketches, compared with text, rests with their ability to intrinsically capture object appearance and structure. Nonetheless, akin to traditional text-based image retrieval, conventional sketch-based image retrieval (SBIR) principally focuses on retrieving images of the same category, neglecting the fine-grained characteristics of sketches. In this paper, we advocate the expressiveness of sketches and examine their efficacy under a novel fine-grained SBIR framework. In particular, we study how sketches enable fine-grained retrieval within object categories. Key to this problem is introducing a mid-level sketch representation that not only captures object pose, but also possesses the ability to traverse sketch and image domains. Specifically, we learn deformable part-based model (DPM) as a mid-level representation to discover and encode the various poses in sketch and image domains independently, after which graph matching is performed on DPMs to establish pose correspondences across the two domains. We further propose an SBIR dataset that covers the unique aspects of fine-grained SBIR. Through in-depth experiments, we demonstrate the superior performance of our SBIR framework, and showcase its unique ability in fine-grained retrieval

    Frequency instability in Er/Yb fiber grating lasers due to heating by nonradiative transitions

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    Author name used in this publication: Demokan, M. S.Version of RecordPublishe

    Currentā€“Voltage Characteristics in Individual Polypyrrole Nanotube, Poly(3,4-ethylenedioxythiophene) Nanowire, Polyaniline Nanotube, and CdS Nanorope

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    In this paper, we focus on currentā€“voltage (Iā€“V) characteristics in several kinds of quasi-one-dimensional (quasi-1D) nanofibers to investigate their electronic transport properties covering a wide temperature range from 300 down to 2 K. Since the complex structures composed of ordered conductive regions in series with disordered barriers in conducting polymer nanotubes/wires and CdS nanowires, all measured nonlinearIā€“Vcharacteristics show temperature and field-dependent features and are well fitted to the extended fluctuation-induced tunneling and thermal excitation model (Kaiser expression). However, we find that there are surprisingly similar deviations emerged between theIā€“Vdata and fitting curves at the low bias voltages and low temperatures, which can be possibly ascribed to the electronā€“electron interaction in such quasi-1D systems with inhomogeneous nanostructures

    Enhanced Coagulation of Titanium Tetrachloride Aided by the Modified Compound Bioflocculant

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    Ā© 2015 American Society of Civil Engineers. The compound bioflocculant (CBF) was modified by graft copolymerization of acrylic amide and dimethyl diallyl ammonium chloride, and the novel copolymer was denoted as MCBF. The effect of MCBF used as coagulant aid with titanium tetrachloride (TiCl4) was investigated for both high and low molecule weight natural organic matter (NOM) removal. Floc characteristics were studied using a laser diffraction particle-sizing device. Results indicated that the monomers were successfully grafted onto the CBF, and the molecule weight and zeta potential of CBF were greatly improved. The MCBF with TiCl4 exhibited synergistic effect by promoting NOM removal, especially at low TiCl4 doses. Additionally, using MCBF as a coagulant aid with TiCl4 can significantly increase the floc growth rate, size, strength, and broken-floc recoverability. The effect of MCBF on fractal dimension of flocs generated by TiCl4 depended on NOM properties. Both coagulation performance and floc properties were significantly affected by dosing sequence

    Biomimetic and bioactive nanofibrous scaffolds from electrospun composite nanofibers

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    Electrospinning is an enabling technology that can architecturally (in terms of geometry, morphology or topography) and biochemically fabricate engineered cellular scaffolds that mimic the native extracellular matrix (ECM). This is especially important and forms one of the essential paradigms in the area of tissue engineering. While biomimesis of the physical dimensions of native ECMā€™s major constituents (eg, collagen) is no longer a fabrication-related challenge in tissue engineering research, conveying bioactivity to electrospun nanofibrous structures will determine the efficiency of utilizing electrospun nanofibers for regenerating biologically functional tissues. This can certainly be achieved through developing composite nanofibers. This article gives a brief overview on the current development and application status of employing electrospun composite nanofibers for constructing biomimetic and bioactive tissue scaffolds. Considering that composites consist of at least two material components and phases, this review details three different configurations of nanofibrous composite structures by using hybridizing basic binary material systems as example. These are components blended composite nanofiber, core-shell structured composite nanofiber, and nanofibrous mingled structure

    Currentā€“Voltage Characteristics in Individual Polypyrrole Nanotube, Poly(3,4-ethylenedioxythiophene) Nanowire, Polyaniline Nanotube, and CdS Nanorope

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    In this paper, we focus on currentā€“voltage (Iā€“V) characteristics in several kinds of quasi-one-dimensional (quasi-1D) nanofibers to investigate their electronic transport properties covering a wide temperature range from 300 down to 2 K. Since the complex structures composed of ordered conductive regions in series with disordered barriers in conducting polymer nanotubes/wires and CdS nanowires, all measured nonlinearIā€“Vcharacteristics show temperature and field-dependent features and are well fitted to the extended fluctuation-induced tunneling and thermal excitation model (Kaiser expression). However, we find that there are surprisingly similar deviations emerged between theIā€“Vdata and fitting curves at the low bias voltages and low temperatures, which can be possibly ascribed to the electronā€“electron interaction in such quasi-1D systems with inhomogeneous nanostructures

    An epidemiologic study of early biologic effects of benzene in Chinese workers.

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    Benzene is a recognized hematotoxin and leukemogen, but its mechanisms of action in humans are still uncertain. To provide insight into these processes, we carried out a cross-sectional study of 44 healthy workers currently exposed to benzene (median 8-hr time-weighted average; 31 ppm), and unexposed controls in Shanghai, China. Here we provide an overview of the study results on peripheral blood cells levels and somatic cell mutation frequency measured by the glycophorin A (GPA) gene loss assay and report on peripheral cytokine levels. All peripheral blood cells levels (i.e., total white blood cells, absolute lymphocyte count, platelets, red blood cells, and hemoglobin) were decreased among exposed workers compared to controls, with the exception of the red blood cell mean corpuscular volume, which was higher among exposed subjects. In contrast, peripheral cytokine levels (interleukin-3, interleukin-6, erythropoietin, granulocyte colony-stimulating factor, tissue necrosis factor-alpha) in a subset of the most highly exposed workers (n = 11) were similar to values in controls (n = 11), suggesting that benzene does not affect these growth factor levels in peripheral blood. The GPA assay measures stem cell or precursor erythroid cell mutations expressed in peripheral red blood cells of MN heterozygous subjects, identifying NN variants, which result from loss of the GPA M allele and duplication of the N allele, and N phi variants, which arise from gene inactivation. The NN (but not N phi) GPA variant cell frequency was elevated in the exposed workers compared with controls (mean +/- SD, 13.9 +/- 8.4 mutants per million cells versus 7.4 +/- 5.2 per million cells, (respectively; p = 0.0002), suggesting that benzene produces gene-duplicating but not gene-inactivating mutations at the GPA locus in bone marrow cells of exposed humans. These findings, combined with ongoing analyses of benzene macromolecular adducts and chromosomal aberrations, will provide an opportunity to comprehensively evaluate a wide range of early biologic effects associated with benzene exposure in humans

    Factors influencing pharmacists and pharmaceutical scientistsā€™ membership in professional organisations: an international survey

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    Background: Professional organisations exist as international or national organisations, with each country establishing at least one national professional association. There remains a knowledge gap about factors that influence professional organisational involvement of pharmacists and pharmaceutical scientists. This study aims to explore the motivators and barriers of pharmacy professionals holding organisation membership from a global perspective. Methods: An online questionnaire was developed and disseminated between May and July 2021. The survey was open to all pharmacists and pharmaceutical scientists. The survey consisted of four sections; demographic information, questions about professional organisations, about the International Pharmaceutical Federation (FIP) and its impact on the members. Data were analysed descriptively. Results: A total of 1033 complete survey responses were received and included in the analysis. Of all respondents, 761 (73.7%) respondents were current members of a professional organisation and 272 (26.3%) were not members of any professional organisation. Overall, findings demonstrated networking, education, training and professional development opportunities as the main interests and anticipated activities, while the lack of clarity or need to join organisation, time, and financial constraints as the main barriers of pharmacy professionals holding membership. The majority of FIP members are satisfied with current FIP activities, and anticipate further networking opportunities, educational resources and grants made available to members. Conclusions: Understanding the perceptions and needs, as well as factors that influence engagement of pharmacists and pharmaceutical scientists is the key to enhancing membership. Professional organisations are highly encouraged to strengthen and target activities according to the identified motivators and barriers

    Electrical Conductivity Studies on Individual Conjugated Polymer Nanowires: Two-Probe and Four-Probe Results

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    <p>Abstract</p> <p>Two- and four-probe electrical measurements on individual conjugated polymer nanowires with different diameters ranging from 20 to 190 nm have been performed to study their conductivity and nanocontact resistance. The two-probe results reveal that all the measured polymer nanowires with different diameters are semiconducting. However, the four-probe results show that the measured polymer nanowires with diameters of 190, 95&#8211;100, 35&#8211;40 and 20&#8211;25 nm are lying in the insulating, critical, metallic and insulting regimes of metal&#8211;insulator transition, respectively. The 35&#8211;40 nm nanowire displays a metal&#8211;insulator transition at around 35 K. In addition, it was found that the nanocontact resistance is in the magnitude of 10<sup>4</sup>&#937; at room temperature, which is comparable to the intrinsic resistance of the nanowires. These results demonstrate that four-probe electrical measurement is necessary to explore the intrinsic electronic transport properties of isolated nanowires, especially in the case of metallic nanowires, because the metallic nature of the measured nanowires may be coved by the nanocontact resistance that cannot be excluded by a two-probe technique.</p
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