• Journal of computational fluids engineering
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• v.20 no.1
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• pp.16-25
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• 2015

The present study investigates the sloshing phenomena in a two-dimensional rectangular tank at a low filling level by using a level set method based on finite volume method. The code validations are performed by comparing between the present results and previous numerical and experimental results, which gives a good agreement. Various excitation frequencies and excitation amplitude of the 30% filling height tank have been considered in order to observe the dependence of the sloshing behavior on the excitation frequency and amplitude. Regardless of excitation amplitude, the maximum value of wall pressure occurs when the excitation frequency reaches the natural frequency. The time sequence of free surface and corresponding streamlines for excitation frequencies have been presented to analysis the variation of wall pressure according to time, which contributes to explain the double peaks in the time variation of wall pressure.

• Parasites, Hosts and Diseases
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• v.46 no.1
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• pp.1-15
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• 2008

Introduction of double-stranded RNA (dsRNA) into some cells or organisms results in degradation of its homologous mRNA, a process called RNA interference (RNAi). The dsRNAs are processed into short interfering RNAs (siRNAs) that subsequently bind to the RNA-induced silencing complex (RISC), causing degradation of target mRNAs. Because of this sequence-specific ability to silence target genes, RNAi has been extensively used to study gene functions and has the potential to control disease pathogens or vectors. With this promise of RNAi to control pathogens and vectors, this paper reviews the current status of RNAi in protozoans, animal parasitic helminths and disease-transmitting vectors, such as insects. Many pathogens and vectors cause severe parasitic diseases in tropical regions and it is difficult to control once the host has been invaded. Intracellularly, RNAi can be highly effective in impeding parasitic development and proliferation within the host. To fully realize its potential as a means to control tropical diseases, appropriate delivery methods for RNAi should be developed, and possible off-target effects should be minimized for specific gene suppression. RNAi can also be utilized to reduce vector competence to interfere with disease transmission, as genes critical for pathogenesis of tropical diseases are knockdowned via RNAi.

• Molecules and Cells
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• v.26 no.6
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• pp.554-557
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• 2008

Double-stranded RNA (dsRNA) induces gene silencing in a sequence-specific manner by a process known as RNA interference (RNAi). The RNA-induced silencing complex (RISC) is a multi-subunit ribonucleoprotein complex that plays a key role in RNAi. VIG (Vasa intronic gene) has been identified as a component of Drosophila RISC; however, the role VIG plays in regulating RNAi is poorly understood. Here, we examined the spatial and temporal expression patterns of VIG-1, the C. elegans ortholog of Drosophila VIG, using a vig-1::gfp fusion construct. This construct contains the 908-bp region immediately upstream of vig-1 gene translation initiation site. Analysis by confocal microscopy demonstrated GFP-VIG-1 expression in a number of tissues including the pharynx, body wall muscle, hypodermis, intestine, reproductive system, and nervous system at the larval and adult stages. Furthermore, western blot analysis showed that VIG-1 is present in each developmental stage examined. To investigate regulatory sequences for vig-1 gene expression, we generated constructs containing deletions in the upstream region. It was determined that the GFP expression pattern of a deletion construct (${\Delta}-908$ to -597) was generally similar to that of the non-deletion construct. In contrast, removal of a larger segment (${\Delta}-908$ to -191) resulted in the loss of GFP expression in most cell types. Collectively, these results indicate that the 406-bp upstream region (-596 to -191) contains essential regulatory sequences required for VIG-1 expression.

• ALGAE
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• v.18 no.3
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• pp.191-197
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• 2003

Histones are important proteins that interact with the DNA double helix to form nucleosome. Two putative histone genes, GjH2A-1 and GjH2A-2 were isolated from a red alga Griffithsia japonica. The putative open reading frame of GjH2A-1 and GjH2A-2 shared high similarity with the previously reported amino acid sequences of histone H2As. They have a motif consisting of seven amino acids A-G-L-Q-F-P-V, which matches the histone H2A motif [AC]-G-L-x-F-P-V. Phylogenetic trees were constructed from amino acid sequences of 38 histone H2As. The histone H2As were divided into two groups: major H2As and H2A.F/Z variants. The major histone H2A group consisted of animals, fungi, plants + green algae, and red algae H2A subgroups. The animal histone H2A subgroup was divided into vertebrates, echinoderms, nematodes, insects, and segmented worms H2As. The putative red algal histone genes, GjH2A-1 and GjH2A-2, constituted an independent lineage. This is the first report on red algal histone genes.

• Investigative Magnetic Resonance Imaging
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• v.20 no.1
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• pp.36-43
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• 2016

Visualization of the tissue loss tangent property can provide distinct contrast and offer new information related to tissue electrical properties. A method for non-invasive imaging of the electrical loss tangent of tissue using magnetic resonance imaging (MRI) was demonstrated, and the effect of loss tangent was observed through simulations assuming a hyperthermia procedure. For measurement of tissue loss tangent, radiofrequency field maps ($B_1{^+}$ complex map) were acquired using a double-angle actual flip angle imaging MRI sequence. The conductivity and permittivity were estimated from the complex valued $B_1{^+}$ map using Helmholtz equations. Phantom and ex-vivo experiments were then performed. Electromagnetic simulations of hyperthermia were carried out for observation of temperature elevation with respect to loss tangent. Non-invasive imaging of tissue loss tangent via complex valued $B_1{^+}$ mapping using MRI was successfully conducted. Simulation results indicated that loss tangent is a dominant factor in temperature elevation in the high frequency range during hyperthermia. Knowledge of the tissue loss tangent value can be a useful marker for thermotherapy applications.

• Computers and Concrete
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• v.21 no.1
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• pp.55-66
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• 2018

A large main shock may consist of numerous aftershocks with a short period. The aftershocks induced by a large main shock can cause the collapse of a structure that has been already damaged by the preceding main shock. These aftershocks are important factors in structural damages. Furthermore, despite what is often assumed in seismic design codes, earthquakes do not usually occur as a single event, but as a series of strong aftershocks and even fore shocks. For this reason, this study investigates the effect and potential of consecutive earthquakes on the response and behavior of concrete structures. At first, six moment resisting concrete frames with 3, 5, 7, 10, 12 and 15 stories are designed and analyzed under two different records with seismic sequences from real and artificial cases. The damage states of the model frames were then measured by the Park and Ang's damage index. From the results of this investigation, it is observed that the sequences of ground motions can almost double the accumulated damage and increased response of structures. Therefore, it is certainly insufficient to ignore this effect in the design procedure of structures. Also, the use of artificial seismic sequences as design earthquake can lead to non-conservative prediction of behavior and damage of structures under real seismic sequences.

• Journal of Power Electronics
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• v.13 no.4
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• pp.558-568
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• 2013

In this paper, a new decoupling technique for a flyback inverter using an active power decoupling circuit with auxiliary winding and a novel switching pattern is proposed. The conventional passive power decoupling method is applied to control Maximum Power Point Tracking (MPPT) efficiently by attenuating double frequency power pulsation on the photovoltaic (PV) side. In this case, decoupling capacitor for a flyback inverter is essentially required large electrolytic capacitor of milli-farads. However using the electrolytic capacitor have problems of bulky size and short life-span. Because this electrolytic capacitor is strongly concerned with the life-span of an AC module system, an active power decoupling circuit to minimize input capacitance is needed. In the proposed topology, auxiliary winding defined as a Ripple port will partially cover difference between a PV power and an AC Power. Since input capacitor and auxiliary capacitor is reduced by Ripple port, it can be replaced by a film capacitor. To perform the operation of charging/discharging decoupling capacitor $C_x$, a novel switching sequence is also proposed. The proposed topology is verified by design analysis, simulation and experimental results.

• Korean Journal Plant Pathology
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• v.11 no.1
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• pp.73-79
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• 1995

Complementary DNAs (cDNAs) to the coat protein gene of an ordinary Korean strain of potato virus Y (PVY-OK) isolated from potato (cv. Superior) were synthesized and cloned into a plasmid pUC119 and sequenced. The RNA of the virus propagated in tobacco (Nicotinaa sylvestris) was extracted by the method of phenol extraction. The first strand of cDNAs to the coat protein penomic RNA of the virus was made by Moloney murine leukemia virus reverse transcriptase. The cDNA were synthesized and amplified by the method of polymerase chain reaction (PCR) using a pair of oligonucleotide primers. PVYCP3P and PVYCP3M. The size of cDNAs inserted in pUC119 plasmid was estimated as about 840 bp upon agarose gel electrophoresis. Double stranded cDNAs were transformed into the competent cell of E. coli JM109. Sequence analysis of cDNAs was conducted by the dideoxynucleotide chain termination method. Homology of cDNAs of the PVY-OK coat protein genomic RNA with those of PVY-O (Japan), PVY-T (Japan), PVY-TH (Japan), PVYN (The Netherlands),and PVYY (France) was represented as 97.3%, 88.9%, 89.3%, 89.6% and 98.5%, respectively. Homology at the amino acid level turned out to the be 97.4%, 92.5%, 92.9%, 92.9% and 98.5%, respectively.

• The Plant Pathology Journal
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• v.30 no.2
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• pp.151-158
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• 2014

Three double-stranded RNAs (dsRNAs), approximately 1.85, 1.65 and 1.27 kb in size, were detected in an isolate of Cytospora sacchari from Iran. Partial nucleotide sequence revealed a 1,284 bp segment containing one ORF that potentially encodes a 405 aa protein. This protein contains conserved motifs related to RNA dependent RNA polymerases (RdRp) that showed similarity to RdRps of partitiviruses. The results indicate that these dsRNAs represent a novel Partitivirus that we tentatively designate Cytospora sacchari partitivirus (CsPV). Treatment of the fungal strain by cyclohexamide and also hyphal tip culture had no effect on removing the putative virus. Phylogenetic analysis of putative RdRp of CsPV and other partitiviruses places CsPV as a member of the genus Partitivirus in the family Partitiviridae, and clustering with Aspergillus ochraceous virus 1.

• Natural Product Sciences
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• v.22 no.3
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• pp.209-215
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• 2016

Kigelia africana (Lam.) Benth. (Bignoniaceae) is a flowering plants in South, Central and West Africa and commonly known as the sausage tree (Eng.); worsboom (Afr.); umVunguta, umFongothi (Zulu); Modukguhlu (North Sotho); Muvevha (Venda). The dried, powdered fruits are used as dressing for wounds and ulcers, haemorrhoids, rheumatism, purgative, skin-firming, lactation in breast-feeding mothers. The aim of this study is to investigate the cytotoxic and apoptotic potentials of 70% ethanolic extracts of Kigelia africana fruits in HCT116 human colon cancer cells. Treatment of Kigelia africana fruits with various concentrations resulted in a sequence of characteristic of apoptosis, including loss of cell viability and morphological changes. Flow cytometry analysis showed Kigelia africana fruits increased the sub-G1 phase (apoptosis) population. Apoptosis confirmed by annexin V-fluorescein isothiocyanate and propidium iodide double staining in HCT116 human colon cancer cell lines. Moreover, analysis of the mechanism indicated that Kigelia africana fruits showed an increased Bax and Bcl-2 expressions in a dose-dependent manner, resulting in activation of hallmarks of apoptotic events, caspase-3, caspase-9 and cleaved poly-ADP-ribose polymerase. This is the first report to demonstrate the cytotoxicity of Kigelia africana fruits on HCT116 human colon cancer cells.