153 research outputs found
An Optical Design Theory for Focused Fragmentation Warhead
Focusing the dispersing direction of fragments with high-accuracy is one key issue in the design of advancedfocused fragmentation warhead for the application of aerial defence and antimissile. The similarity of mechanismbetween the focusing of geometrical optics and focusing of fragments is analysed in details, and it is proved thatthe driving direction of warhead fragment can be controlled according to the theory of geometrical optics. A newdesign model and method for Focused fragmentation warhead is obtained. The design is preliminary proved to beefficient by some tests, and it is found that 85 per cent of total fragment of the warhead can be focused within thedesigned focusing zone, which is an improvement to the 70 per cent obtained by other methods.Defence Science Journal, 2012, 62(4), pp.205-211, DOI:http://dx.doi.org/10.14429/dsj.62.106
The establishment and application of a dual Nano-PCR detection method for feline calicivirus and feline herpesvirus type I
Feline calicivirus (FCV) and Feline herpesvirus type I (FHV-I) are the main pathogens causing upper respiratory tract infections in cats, and some wild animals. These two viruses always coinfection and cause serious harm to pet industry and wild animals protection. Established a rapid and accurate differential diagnosis method is crucial for prevention and control of disease, however, the current main detection method for these two viruses, either is low sensitivity (immunochromatographic strip), or is time-consuming and cannot differential diagnosis (conventional single PCR). Nanoparticle-assisted polymerase chain reaction (Nano-PCR) is a recently developed technique for rapid detection method of virus and bacteria. In this study, we described a dual Nano-PCR assay through combining the nanotechnology and PCR technology, which for the clinical simultaneous detection of FCV and FHV-I and differential diagnosis of upper respiratory tract infections in cats or other animals. Under optimized conditions, the optimal annealing temperature for dual Nano-PCR was 51.5°C, and specificity test results showed it had no cross reactivity to related virus, such as feline panleukopenia virus (FPV), feline Infectious peritonitis virus (FIPV) and rabies virus (RABV). Furthermore, the detection limit of dual Nano-PCR for FCV and FHV-I both were 1 × 10−8 ng/μL, convert to number of copies of virus DNA was 6.22 × 103copies/μL (FCV) and 2.81 × 103copies/μL (FHV-I), respectively. The dual Nano-PCR detected result of 52 cat clinical samples, including ocular, nasal and faecal swabs, and (3 FCV-positive samples), was consistent with ordinary PCR and the clinical detection results. The dual Nano-PCR method established in this study with strong specificity and high sensitivity can be used for virus nucleic acid (FCV and FHV-I) detection of clinical samples of feline upper respiratory tract infections feline calicivirus and feline herpesvirus while providing support for the early diagnosis of cats that infected by FCV and FHV-I
AMI en Latinoamérica Aproximación, análisis y propuesta de medición sobre el contexto de la Alfabetización Mediática e Informacional en América Latina
Esta tesis doctoral desarrolla una metodología para la evaluación de la alfabetización mediática e informacional (AMI), que se basa en los marcos propuestos por la UNESCO (2011, 2013) y la Comisión Europea (Celot y Pérez Tornero, 2009), brindando una adaptación de las recomendaciones diseñadas por estos dos grandes representantes de la AMI aplicable al contexto específico de América Latina. También hace una revisión de literatura sobre las teorías generales relacionadas con la alfabetización mediática e informacional, así como de estudios en AMI llevados a cabo en diferentes países, principalmente en los once seleccionados para esta investigación. De esta manera, se plantea un enfoque amplio sobre la AMI que tiene en cuenta diversos autores e instituciones que trabajan en este campo (ACRL, 2000; Ainley et al., 2012; NAP-ICTL, 2012; Pérez-Tornero, 2007; UNESCO, 2008; Celot y Pérez-Tornero 2009; Lau y Cortés, 2009; Renee Hobbs, 2010; UNESCO, 2011, 2013; Giraldo et al., 2014, entre otros). Teorías relacionadas con la edu-comunicación, la alfabetización mediática, estudios de medios, alfabetización informacional, alfabetización TIC/digital, alfabetizaciones múltiples, etc., han sido comparadas y analizadas. El resultado es la creación de un marco teórico sólido tanto sobre la competencia mediática como sobre la evaluación del contexto AMI. El estudio se basa en un profundo análisis de contenidos que sistematiza variables relacionadas con políticas públicas, planes de estudios, planes nacionales en TIC, seguridad cibernética y elementos relacionados con la AMI en general (alfabetización informacional, alfabetización digital, competencia mediática) en los once países estudiados. También tiene en cuenta un amplio cuestionario aplicado a una muestra de 44 expertos en AMI provenientes de Argentina, Chile, Colombia, Costa Rica, Ecuador, México, Panamá, Perú, República Dominicana, Uruguay y Venezuela. La investigación muestra cómo los países de América Latina se están adaptando a la sociedad del conocimiento -a velocidades bastante diferentes- y describe (y se centra en ello) un escenario de rápido movimiento en el que se observa la manera en que algunos países de la región comienzan a concentrar sus esfuerzos en acciones que van más allá de la fase embrionaria de generación de oportunidades de acceso a las TIC (infraestructura TI en general, programas 1:1, ciber-centros, construcción de redes, etc.). También muestra cómo los países del mismo nivel de ingresos (medio-alto) han llevado a cabo diferentes estrategias digitales que, en algunos casos, han conducido a resultados de alto impacto. El resultado de esta investigación es una propuesta de "Índice de preparación AMI" y un amplio primer mapeo de los factores que favorecen a la AMI en la región.This thesis develops an assessment methodology on Media and Information Literacy (MIL), which is based on the frameworks proposed by UNESCO (2011, 2013) and the European Commission (Celot & Pérez Tornero, 2009), adapting the directions given by these two major representatives in the field of MIL to the specific context of Latin America. It also makes a literature review on media and information literacy general theories as well as on MIL studies carried out in different countries, mainly in the eleven selected for this research. A broad approach to MIL is drafted taking into account several authors and institutions working on this field (ACRL, 2000; Ainley et al., 2012; NAP-ICTL, 2012; Pérez-Tornero, 2007; UNESCO, 2008; Celot & Pérez-Tornero, 2009; Lau & Cortés, 2009; Renee Hobbs, 2010; UNESCO, 2011, 2013; Giraldo et al., 2014, among others). Theories related to edu-communication, media literacy, media studies, information literacy, digital/ICT literacy, multiple literacies, etc. have been compared and analyzed. The result is the creation of a robust theoretical framework both on media competence and on MIL context assessment. The study relies on a deep content analysis that systematizes variables related to public policy, school curriculum, ICT plans, cyber-security, and media and information literacy elements (informational literacy, digital literacy, media competence) in the eleven countries studied. It also takes into account a comprehensive questionnaire with a sample of 44 MIL experts from Argentina, Chile, Colombia, Costa Rica, Ecuador, Mexico, Panama, Peru, Dominican Republic, Uruguay and Venezuela. The research shows how countries in Latin America are adapting to the Knowledge Society -at very different speeds- and describes (and focuses on) a fast-moving scenario where some countries of the region are starting to concentrate their efforts on actions that go beyond the embryonic stage of generating opportunities to access ICT (general IT infrastructure, 1:1 programs, cyber-centers, networks building, etc.). It also shows how countries on the same income level (mid-high) have run very different digital strategies which, in some cases, have led to high impact outcomes. The result of this research is a "MIL Readiness Index" proposal and a rich first mapping of the MIL enabling factors in the region
Anti-tumor effect of adenovirus-mediated gene transfer of pigment epithelium-derived factor on mouse B16-F10 melanoma
<p>Abstract</p> <p>Background</p> <p>Angiogenesis plays an important role in tumor growth, invasion, and eventually metastasis. Antiangiogenic strategies have been proven to be a promising approach for clinical therapy for a variety of tumors. As a potent inhibitor of tumor angiogenesis, pigment epithelium-derived factor (PEDF) has recently been studied and used as an anticancer agent in several tumor models.</p> <p>Methods</p> <p>A recombined adenovirus carrying PEDF gene (Ad-PEDF) was prepared, and its expression by infected cells and in treated animals was confirmed with Western blotting and ELISA, respectively. Its activity for inhibiting human umbilical vein endothelial cell (HUVEC) proliferation was tested using the MTT assay. C57BL/6 mice bearing B16-F10 melanoma were treated with i.v. administration of 5 × 10<sup>8 </sup>IU/mouse Ad-PEDF, or 5 × 10<sup>8 </sup>IU/mouse Ad-Null, or normal saline (NS), every 3 days for a total of 4 times. Tumor volume and survival time were recorded. TUNEL, CD31 and H&E stainings of tumor tissue were conducted to examine apoptosis, microvessel density and histological morphology changes. Antiangiogenesis was determined by the alginate-encapsulated tumor cell assay.</p> <p>Results</p> <p>The recombinant PEDF adenovirus is able to transfer the PEDF gene to infected cells and successfully produce secretory PEDF protein, which exhibits potent inhibitory effects on HUVEC proliferation. Through inhibiting angiogenesis, reducing MVD and increasing apoptosis, Ad-PEDF treatment reduced tumor volume and prolonged survival times of mouse bearing B16-F10 melanoma.</p> <p>Conclusion</p> <p>Our data indicate that Ad-PEDF may provide an effective approach to inhibit mouse B16-F10 melanoma growth.</p
Corrigendum to: The TianQin project: current progress on science and technology
In the originally published version, this manuscript included an error related to indicating the corresponding author within the author list. This has now been corrected online to reflect the fact that author Jun Luo is the corresponding author of the article
Potential of Core-Collapse Supernova Neutrino Detection at JUNO
JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve
Detection of the Diffuse Supernova Neutrino Background with JUNO
As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO
Apelin attenuates the osteoblastic differentiation of aortic valve interstitial cells via the ERK and PI3-K/Akt pathways
Real-time Monitoring for the Next Core-Collapse Supernova in JUNO
Core-collapse supernova (CCSN) is one of the most energetic astrophysical
events in the Universe. The early and prompt detection of neutrinos before
(pre-SN) and during the SN burst is a unique opportunity to realize the
multi-messenger observation of the CCSN events. In this work, we describe the
monitoring concept and present the sensitivity of the system to the pre-SN and
SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is
a 20 kton liquid scintillator detector under construction in South China. The
real-time monitoring system is designed with both the prompt monitors on the
electronic board and online monitors at the data acquisition stage, in order to
ensure both the alert speed and alert coverage of progenitor stars. By assuming
a false alert rate of 1 per year, this monitoring system can be sensitive to
the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos
up to about 370 (360) kpc for a progenitor mass of 30 for the case
of normal (inverted) mass ordering. The pointing ability of the CCSN is
evaluated by using the accumulated event anisotropy of the inverse beta decay
interactions from pre-SN or SN neutrinos, which, along with the early alert,
can play important roles for the followup multi-messenger observations of the
next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
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