52 research outputs found

    Effective Stress Analysis of a Sheet Pile Quaywall

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    In 1983, Nihonkai Chubu Earthquake of magnitude 7.7 hit northern part of Japan. The earthquake caused damage to quaywalls at Akita Port located about 100 km from the epicenter. The damage was associated with the liquefaction of backfill sand. In order to analyze the mechanism of the damage, soils are taken from the site for laboratory tests. The record of the earthquake motion is digitized. Based on these investigations, a two dimensional effective stress analysis is conducted. The model used in this study consists of a multiple virtual simple shear mechanisms oriented in arbitrary directions. The results of the effective stress analysis indicate that a fundamental mechanism in producing deformation of the soil and the structure is due to the initial stress and its release in accordance with the progress of cyclic mobility. This mechanism of deformation is quite different from that indicated by the conventional Newmark\u27s sliding block concept

    The Emergence of HIV-1 Transmitted Drug Resistance Mutations Among Antiretroviral Therapy-naive Individuals in Buleleng, Bali, Indonesia

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    Background: the global scale-up of antiretroviral therapy (ART) is the primary factor contributing to the decline in deaths from acquired immune deficiency syndrome (AIDS)-related illnesses. However, the emergence of transmitted drug resistance (TDR) compromises the effects of ART in treatment-naïve individuals, which may hinder treatment success. The present study aimed to identify the presence of TDR among treatment-naive individuals in Buleleng, Bali, which is currently ranked sixth among Indonesian provinces with the highest cumulative human immunodeficiency virus type 1 (HIV-1) infection cases. Methods: thirty-nine ART-naive individuals in Buleleng Regency General Hospital were enrolled in the present study. Blood samples from participants were subjected to a genotypic analysis. Results: 28 protease (PR) and 30 reverse transcriptase (RT) genes were successfully amplified and sequenced from 37 samples. HIV-1 subtyping revealed CRF01_AE as the dominant circulating recombinant form in the region. No TDR for PR inhibitors was detected; however, TDR for RT inhibitors was identified in five out of 30 samples (16.7%). Conclusion: these results indicate the emergence of TDR among ART-naive individuals in Buleleng, Bali. This issue warrants serious consideration because TDR may hamper treatment success and reduce ART efficacy among newly diagnosed individuals. Continuous surveillance with a larger sample size is necessary to monitor TDR among ART-naive individuals

    A NEW COPPER (II)-IMIDAZOLE DERIVATIVE EFFECTIVELY INHIBITS REPLICATION OF DENV-2 IN VERO CELL

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    Background: Dengue is a kind of infectious disease that was distributed in the tropical and sub-tropical areas. To date, there is no clinically approved dengue vaccine or antiviral for humans, even though there have been great efforts towards this end. Therefore, finding the effective compound against dengue virus (DENV) replication is very important. Among the complex compounds, copper(II)-imidazole derivatives are of interest because of their biological and medicinal benefits. Materials and Methods: In the present study, antiviral activity of [Cu(2,4,5-triphenylimidazole)2]n, was evaluated against different stages of dengue virus type 2 (DENV-2) replication in Vero cell using focus forming unit reduction assay and quantitative ELISA. Results: [Cu(2,4,5-triphenylimidazole)2]n inhibited DENV-2 replication in Vero cells with IC50 = 2.3 μg/ml and SI= 19.42 when cells were treated 2 days after virus infection, whereas its CC50 for cytotoxicity to Vero cells was 44.174 μg/ml. Conclusion: The compound has high anti-DENV2 activity, less toxicity, and a high possibility to be considered a drug candidate

    Sero- and Molecular Epidemiology of HIV-1 in Papua Province, Indonesia

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    Background: human immunodeficiency virus (HIV) infection and acquired immune deficiency syndrome (AIDS) cause serious health problems and affect the Indonesian economy. Papua province has the highest prevalence of HIV infection in the country; however, epidemiological data are limited. Therefore, in order to reveal the current situation of HIV/AIDS in Papua province, sero- and molecular epidemiological studies of HIV were conducted. Methods: serological tests were conducted on 157 healthy individuals from the general population residing in Paniai, Papua. In addition, a molecular epidemiological study was then conducted on HIV type 1 (HIV-1) genes derived from infected individuals. Peripheral blood samples from HIV-1-positive individuals and 15 additionally enrolled, previously confirmed HIV-1-positive individuals were subjected to a genotypic analysis. Results: serological tests revealed that 2 out of 157 (1.27%) healthy individuals were HIV-positive. In addition, HIV-1 subtyping revealed that subtype B and CRF01_AE were the major subtype and circulating recombinant form (CRF) of HIV-1 prevalent in the region, while subtype A1 and a recombinant form including viral gene fragments of CRF01_AE and subtype B was also detected. In addition, HIV drug resistance-associated major mutations were detected in the reverse transcriptase gene derived from infected individual on antiretroviral therapy. Conclusion: these results provide important information for clearer understanding on the current situation of HIV/AIDS in Papua province in Indonesia

    HIV-1 transmitted drug resistance mutations among antiretroviral therapy-Naïve individuals in Surabaya, Indonesia

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    BACKGROUND: The emergence of transmitted drug resistance (TDR) compromises the effect of antiretroviral therapy (ART), resulting in treatment failure of human immunodeficiency virus (HIV) disease. Although more than a decade has passed since ART was introduced into Indonesia, information on TDR is limited. Here, a genotypic study of TDR among ART-naïve individuals was conducted in Surabaya, Indonesia. METHOD: HIV-1 seropositive participants were recruited from the communities of commercial sex workers and intravenous drug users as well as from the university teaching hospital in Surabaya. Protease (PR) and reverse transcriptase (RT) genes were sequenced in order to conduct HIV-1 subtyping and phylogenetic analysis and to detect TDR. TDR was defined as the presence of at least one surveillance drug resistance mutation on the WHO list or major drug resistance mutations in the International AIDS Society-USA panel. RESULT: Fifty two and 47 of the PR and RT genes, respectively, were successfully sequenced in the 58 samples. HIV-1 subtyping revealed that 86.3% (50/58) of the sequenced samples were classified as CRF01_AE, 8.6% as subtype B, 3.4% as B/CRF01_AE, and 1.7% as A/G/CRF01_AE. TDR of PR inhibitors was not detected in this study. In contrast, TDR of RT inhibitors was detected in 4.3% (2/47) of samples. In addition, minor drug resistance mutations were detected in 98.1% (51/52) and 12.8% (6/47) of PR and RT genes, respectively. CONCLUSION: This study clarified the predominance of the CRF01_AE strain in Surabaya, Indonesia. The prevalence of TDR was below 5%, indicating that the currently available first-line regimen is still effective in Surabaya. However, the prevalence might be underestimated since we detected only major population of HIV-1 in individuals. Therefore, continuous surveillance is required in order to detect the emergence of TDR in the early phase. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12981-015-0046-y) contains supplementary material, which is available to authorized users

    Robust speech dereverberation based on non-negativity and sparse nature of speech spectrograms

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    This paper presents a blind dereverberation method designed to recover the subband envelope of an original speech signal from its reverberant version. The problem is formulated as a blind deconvolution problem with non-negative constraints, regularized by the sparse nature of speech spectrograms. We derive an iterative algorithm for its optimization, which can be seen as a special case of the non-negative matrix factor deconvolution. We confirmed through experiments that the algorithm is fast and robust to speaker movement. Index Terms — Speech dereverberation, temporal envelope filtering, non-negative blind deconvolution, sparseness 1

    Construction of Fosmid-based SARS-CoV-2 replicons for antiviral drug screening and replication analyses in biosafety level 2 facilities

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    The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), has necessitated the global development of countermeasures since its outbreak. However, current therapeutics and vaccines to stop the pandemic are insufficient and this is mainly because of the emergence of resistant variants, which requires the urgent development of new countermeasures, such as antiviral drugs. Replicons, self-replicating RNAs that do not produce virions, are a promising system for this purpose because they safely recreate viral replication, enabling antiviral screening in biosafety level (BSL)-2 facilities. We herein constructed three pCC2Fos-based RNA replicons lacking some open reading frames (ORF) of SARS-CoV-2: the Δorf2–8, Δorf2.4, and Δorf2 replicons, and validated their replication in Huh-7 cells. The functionalities of the Δorf2–8 and Δorf2.4 replicons for antiviral drug screening were also confirmed. We conducted puromycin selection following the construction of the Δorf2.4-puro replicon by inserting a puromycin-resistant gene into the Δorf2.4 replicon. We observed the more sustained replication of the Δorf2.4-puro replicon by puromycin pressure. The present results will contribute to the establishment of a safe and useful replicon system for analyzing SARS-CoV-2 replication mechanisms as well as the development of novel antiviral drugs in BSL-2 facilities

    Japanese Encephalitis DNA Vaccines with Epitope Modification Reduce the Induction of Cross-Reactive Antibodies against Dengue Virus and Antibody-Dependent Enhancement of Dengue Virus Infection

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    Infection with viruses belonging to the genus Flavivirus, such as Japanese encephalitis virus (JEV) and dengue virus (DENV), is a worldwide health problem. Vaccines against JEV and DENV are currently available. However, the dengue vaccine possibly increases the risk of severe dengue due to antibody-dependent enhancement (ADE). Moreover, the Japanese encephalitis (JE) vaccine reportedly induces cross-reactive ADE-prone antibodies against DENV, potentially leading to symptomatic dengue. Therefore, it is necessary to eliminate the risk of ADE through vaccination. In this study, we attempted to develop a JE vaccine that does not induce ADE of DENV infection using an epitope modification strategy. We found that an ADE-prone monoclonal antibody cross-reactive to DENV and JEV recognizes the 106th amino acid residue of the E protein of JEV (E-106). The JE DNA vaccine with a mutation at E-106 (E-106 vaccine) induced comparable neutralizing antibody titers against JEV to those induced by the wild-type JE DNA vaccine. Meanwhile, the E-106 vaccine induced 64-fold less cross-reactive ADE-prone antibodies against DENV. The mutation did not compromise the protective efficacy of the vaccine in the lethal JEV challenge experiment. Altogether, the modification of a single amino acid residue identified in this study helped in the development of an ADE-free JE vaccine
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