The microbial zoo in the C. elegans intestine: Bacteria, fungi and viruses

Press freedom has become one of the major challenges facing Journalism practice in the world. This paper explores the factors hindering press freedom in Nigeria using some relevant examples. The researcher used the qualitative method of research; using secondary data comprising of books and journals. The study is embedded on social responsibility theory. The study reveals that there are a lot of factors in Nigeria that hinders press freedom ranging from secrecy, legal pressure, direct censorship and force among others. Findings also reveal that Nigerian press freedom is a paradox and only exist on paper i.e. in the constitution but not in practice. The study recommends that since press freedom is granted in the constitution of Nigeria, there should be statutory backup and in order not to hinder press freedom, journalist should be allowed to have access to government sources and records so long as it will not bring chaos to the society at large

Engineering recombinant orsay virus directly in the metazoan host Caenorhabditis elegans

The recent identification of Orsay virus, the first virus that is capable of naturally infecting Caenorhabditis elegans, provides a unique opportunity to explore host-virus interaction studies in this invaluable model organism. A key feature of this system is the robust genetic tractability of the host, C. elegans, which would ideally be complemented by the ability to genetically manipulate Orsay virus in parallel. To this end, we developed a plasmid-based reverse genetics system for Orsay virus by creating transgenic C. elegans strains harboring Orsay virus cDNAs. Both wild-type and mutant Orsay viruses, including a FLAG epitope-tagged recombinant Orsay virus, were generated by use of the reverse genetics system. This is the first plasmid-based virus reverse genetics system in the metazoan C. elegans. The Orsay virus reverse genetics we established will serve as a fundamental tool in host-virus interaction studies in the model organism C. elegans. IMPORTANCE To date, Orsay virus is the first and the only identified virus capable of naturally infecting Caenorhabditis elegans. C. elegans is a simple multicellular model organism that mimics many fundamental features of human biology and has been used to define many biological properties conserved through evolution. Thus, the Orsay virus-C. elegans infection system provides a unique opportunity to study host-virus interactions. In order to take maximal advantage of this system, the ability to genetically engineer mutant forms of Orsay virus would be highly desirable. Most efforts to engineer viruses have been done with cultured cells. Here we describe the creation of mutant viruses directly in the multicellular organism C. elegans without the use of cell culture. We engineered a virus expressing a genetically tagged protein that could be detected in C. elegans. This provides proof of concept for modifying Orsay virus, which will greatly facilitate studies in this experimental system

Indole-thiophene conjugate inhibits proliferation of human cervical cancer cell lines through DNA damage

Purpose: To investigate the inhibitory effect of indole-thiophene conjugate (ITC) against cervical cancer cells. Methods: The effect of ITC on the proliferation of cervical cells was determined using 3 (4,5 dimethylthiazol 2 yl) 2,5 diphenyltetrazolium bromide (MTT) assay. The apoptosis-inducing effect of ITC was analysed with flow cytometry, while its effect on cell invasion was assessed using Transwell assay. Results: ITC inhibited proliferation of HeLa and Caski cancer cell lines, but it had no cytotoxicity against HCvEpC normal epithelial cells. Exposure to ITC at a dose of 12 μmol/L reduced the viability of HeLa and Caski cells to 22.56 and 24.78 %, respectively (p < 0.05). ITC treatment of HeLa cells enhanced the proportion of apoptotic cells. Exposure to ITC at a dose of 12 μmol/L led to near-complete inhibition of the invasive potential of HeLa cells. Moreover, exposure of HeLa cells to ITC downregulated the protein expressions of MMP-2 and MMP-9 (p < 0.05). The expressions of Bcl-2, p-ERK1/2 and p-Akt were markedly decreased in HeLa cells by ITC exposure. In addition, ITC increased Bax expression, and decreased Bcl-2/Bax ratio (p < 0.05). Conclusion: ICT inhibits the proliferation and invasion of cervical cancer cells, and induces their apoptosis. It exhibits these effects via the suppression of Akt and ERK phosphorylation, thereby downregulating the PI3K and MAPK pathways. Therefore, ITC may be beneficial for the treatment of cervical cancer

Numerical analysis on magnetic leakage field of pipeline defect

Pipeline magnetic flux leakage inspection, mainly used for pipeline defect detection, is an important means of inner examination technology on pipeline. Flux leakage testing can't obtain valid defect identification signals by one hundred percent because of magnetization of the magnetic leakage field, the measured shape, size and location of pipeline defects, materials and operating conditions, and lift-off value, pole pitch and the length of steel brush during the measurement as well as forged pipe fittings such as welding seam, stiffener, flange and tee on the pipeline to be tested. This article reaches a conclusion that magnetic flux density distribution is influenced by the depth and width of defect through respectively researching magnetic leakage field of individual defect and double defects (thickness type) by finite-element method. It also conducts the numerical analysis on pipeline welding seam, stiffener, flange (increased wall thickness type) and tee (compound) leakage magnetic field in detection conditions of the same direction, and concludes their distribution rules of magnetic flux density. The characteristic parameters of distinguishing defect magnetic flux leakage field and the part of the pipeline magnetic flux leakage, derived from analysis and comparison of results on defective pipeline and conduit joint, stiffener, flange and tee magnetic flux leakage, provide a foundation of qualitative identification for accurately recognizing pipeline defect and eliminating the impact of other ancillary fittings on a pipe on pipeline magnetic flux leakage, and they can also offer infallible data to pipeline maintenance as a basis of quantitative analysis

Entropy generation and exergy destruction in condensing steam flow through turbine blade with surface roughness

In the steam turbine, the wetness loss due to vapor condensation is one of the most crucial losses at low-pressure stage. This study focused on entropy generation and exergy destruction of condensing steam flow in turbine blade with the roughness. The governing equations including entropy transport equation combined with condensation model, transition SST model and roughness correlation were established and verified by experiments and theory. Flow field behaviors, such as wetness fraction, intermittency and turbulent viscosity distributions, controlled by the deviation angle were obtained to evaluate effects of back pressure ratio and surface roughness. The mass-averaged wetness fraction at outlet was also extracted considering the influence of uneven mass flux. Finally, each part of entropy generation derived from viscous, heat conduction, phase change and aerodynamic losses and exergy destruction ratio were analyzed. Research shows that roughness plays an important part in the intermittency and turbulent viscosity. The mass-averaged wetness fraction at outlet sharply drops with back pressure ratio but slightly decreases with the roughness. With the roughness rising or back pressure dropping, the entropy generation grows resulting in more exergy destruction. The maximum value of the total entropy generation is 84.520 J·kg−1·K−1, corresponding exergy destruction is 25.187 kJ·kg−1 and exergy destruction ratio is 4.43%

Finite Element Analysis on a Square Canister Piezoelectric Energy Harvester in Asphalt Pavement

Abstrac

Identity-Based Higncryption

Identity-based cryptography (IBC) is fundamental to security and privacy protection. Identity-based authenticated encryption (i.e., signcryption) is an important IBC primitive, which has numerous and promising applications. After two decades of research on signcryption,recently a new cryptographic primitive, named higncryption, was proposed. Higncryption can be viewed as privacy-enhanced signcryption, which integrates public key encryption, entity authentication, and identity concealment (which is not achieved in signcryption) into a monolithic primitive. Here, briefly speaking, identity concealment means that the transcript of protocol runs should not leak participants\u27 identity information. In this work, we propose the first identity-based higncryption (IBHigncryption). The most impressive feature of IBHigncryption, among others, is its simplicity and efficiency. The proposed IBHigncryption scheme is essentially as efficient as the fundamental CCA-secure Boneh-Franklin IBE scheme [18], while offering entity authentication and identity concealment simultaneously. Compared to the identity-based signcryption scheme [11], which is adopted in the IEEE P1363.3 standard, our IBHigncryption scheme is much simpler, and has significant efficiency advantage in total. Besides, our IBHigncryption enjoys forward ID-privacy, receiver deniability and x-security simultaneously. In addition, the proposed IBHigncryption has a much simpler setup stage with smaller public parameters, which in particular does not have the traditional master public key. Higncryption is itself one-pass identity-concealed authenticated key exchange without forward security for the receiver. Finally, by applying the transformation from higncryption to identity-concealed authenticated key exchange (CAKE), we get three-pass identity-based CAKE (IB-CAKE) with explicit mutual authentication and strong security (in particular, perfect forward security for both players). Specifically, the IB-CAKE protocol involves the composition of two runs of IBHigncryption, and has the following advantageous features inherited from IBHigncryption: (1) single pairing operation: each player performs only a single pairingoperation; (2) forward ID-privacy; (3) simple setup without master public key; (4) strong resilience to ephemeral state exposure, i.e., x-security; (5) reasonable deniability

Robust H

The robust H∞ filtering problem for a class of network-based systems with random sensor delay is investigated. The sensor delay is supposed to be a stochastic variable satisfying Bernoulli binary distribution. Using the Lyapunov function and Wirtinger’s inequality approach, the sufficient conditions are derived to ensure that the filtering error systems are exponentially stable with a prescribed H∞ disturbance attenuation level and the filter design method is proposed in terms of linear matrix inequalities. The effectiveness of the proposed method is illustrated by a numerical example