Unjuk Kerja Separator Gas Liquid Cylindical Cyclone (GLCC Metering Loop)

Separator siklon silinder vertikal (Gas Liquid Cylindrical Cyclones) merupakan alat pemisahan aliran multifase yang umum dipergunakan dalam industri perminyakan. Penelitian ini bertujuan untuk mengevaluasi unjuk kerja dan perilaku hidrodinamika fluida separator GLCC metering loop pada pemisahan aliran campuran udara dan air. Eksperimen dilakukan dengan membuat separator skala uji laboratorium menggunakan pipa acrylic plexyglass diameter 6,25 cm, tinggi 140 cm dengan sistem inlet tangensial pada sudut inklinasi 30o, serta dilengkapi 5 variasi posisi saluran keluaran. Percobaan dilakukan dengan memvariasikan debit udara dan efek posisi saluran keluaran (recombination point). Beberapa aspek penting seperti kecepatan superficial gas (Vsg), kecepatan superficial cairan (Vsl), level cairan kesetimbangan (Leq), liquid carry over (LCO) dan gas carry under (GCU) menjadi perhatian selama percobaan. Hasil penelitian menunjukkan bahwa empat regim aliran yaitu aliran gelembung (bubble flow), aliran gelembung paket (packed bubble flow), aliran kantung gas atau sumbat cair (slug flow) dan aliran acak (churn flow) dipengaruhi oleh konfigurasi rasio aliran gas-cairan dan posisi rekombinasinya. Rasio kecepatan superfisial antara udara dan cairan memainkan peran penting terhadap terbentuknya regim aliran dan ketinggian level cairan kesetimbangan.

SANTA-SIM: simulating viral sequence evolution dynamics under selection and recombination

Simulations are widely used to provide expectations and predictive distributions under known conditions against which to compare empirical data. Such simulations are also invaluable for testing and comparing the behaviour and power of inference methods. We describe SANTA-SIM, a software package to simulate the evolution of a population of gene sequences forwards through time. It models the underlying biological processes as discrete components: replication, recombination, point mutations, insertion–deletions, and selection under various fitness models and population size dynamics. The software is designed to be intuitive to work with for a wide range of users and executable in a cross-platform manner.

SANTA-SIM: Simulating Viral Sequence Evolution Dynamics Under Selection and Recombination

Simulations are widely used to provide expectations and predictive distributions under known conditions against which to compare empirical data. Such simulations are also invaluable for testing and comparing the behavior and power of inference methods. We describe SANTA-SIM, a software package to simulate the evolution of a population of gene sequences forwards through time. It models the underlying biological processes as discrete components: replication, recombination, point mutations, insertion-deletions, and selection under various fitness models and population size dynamics. The software is designed to be intuitive to work with for a wide range of users and executable in a cross-platform manner.

Characterization of a novel recombination event in the Deformed wing bee virus polymerase gene

Honeybee populations are known to be infected by numerous viruses. Reverse transcription-PCR (RT-PCR) of regions of the RNA-dependent RNA polymerase is often used to diagnose the presence in apiaries and also to classify the type of virus detected. In this report, through analysis of the RdRp gene, we describe a novel recombination event in the DWV genome. Similarity plot analysis amplified from hundred positive individuals identified a previously undescribed recombination point in the 5’ region of the polymerase gene. To our knowledge this is the first description of recombination in the DWV polymerase gene and highlights the continuous genetic evolution of these viruses.

C-Myc misregulation triggers complex process of genomic instability

Genetic stability is an essential factor for the cellular integrity. Failure in its maintenance leads to accumulation of errors derived from the process of DNA replication, cellular metabolism, action of endogenous and exogenous DNA damaging factors and eventually, as a final outcome tumor initiation and progression occur. Overall manifestation of c-Myc deregulation in many tumors and different mechanisms of Myc?s action toward genomic stability suggest that this gene plays a central role in destabilization of genome. Microarray studies and functional genomics approach led us to conclusion that c-Myc can control nuclear architecture in global fashion since about 15% of all cellular genes are regulated by this transcription factor. Deregulation of c-Myc gene triggers a composite network of genomic instability that may result in several different outcomes as: locus-specific amplification, formation of extrachromosomal elements (EEs), chromosomal instability, long-range illegitimate recombination, point mutations, DNA breakage and nuclear structure reorganization. This review outlines the growing evidence that c-Myc oncogene induces a complex network of genomic instability and describes systems and circumstances under which deregulation of c-Myc results in specific types of genomic alteration.

Analysis of a Larger SNP Dataset from the HapMap Project Confirmed That the Modern Human A Allele of the ABO Blood Group Genes Is a Descendant of a Recombinant between B and O Alleles

The human ABO blood group gene consists of three main alleles (A, B, and O) that encode a glycosyltransferase. The A and B alleles differ by two critical amino acids in exon 7, and the major O allele has a single nucleotide deletion (Δ261) in exon 6. Previous evolutionary studies have revealed that the A allele is the most ancient, B allele diverged from the A allele with two critical amino acid substitutions in exon 7, and the major O allele diverged from the A allele with Δ261 in exon 6. However, a recent phylogenetic network analysis study showed that the A allele of humans emerged through a recombination between the B and O alleles. In the previous study, a restricted dataset from only two populations was used. In this study, therefore, we used a large single nucleotide polymorphism (SNP) dataset from the HapMap Project. The results indicated that the A101-A201-O09 haplogroup was a recombinant lineage between the B and O haplotypes, containing the intact exon 6 from the B allele and the two critical A type sites in exon 7 from the major O allele. Its recombination point was assumed to be located just behind Δ261 in exon 6.

Near-Full Genome Characterisation of Two Natural Intergenotypic 2k/1b Recombinant Hepatitis C Virus Isolates

Few natural intergenotypic hepatitis C virus (HCV) recombinants have been characterised, and only RF1_2k/1b has demonstrated widespread transmission. The near-full length genome sequences for two cases of 2k/1b recombinants (CYHCV037 and CYHCV093) sampled in Cyprus were obtained using strain-specific RT-PCR amplification and sequencing protocols. Sequence analysis confirmed their similarity with the original RF1_2k/1b strain from St. Petersburg, N687. These two isolates significantly contribute to the sequence data available on this recombinant and confirm its increasing spread among individuals from Eastern Europe, and its association with transmission through intravenous drug use. Phylogenetic analyses reveal clustering of the sequence 3′ to the recombination point, not seen in the topology of the 5′ sequences, implying a more complicated evolutionary history than that held to date. The increasing cases of HCV recombinant strains underline the requirement of their contribution to the standardised rules of HCV classification and nomenclature, molecular epidemiology, diagnosis, and treatment.

Norovirus recombination

RNA recombination is a significant driving force in viral evolution. Increased awareness of recombination within the genus Norovirus of the family Calicivirus has led to a rise in the identification of norovirus (NoV) recombinants and they are now reported at high frequency. Currently, there is no classification system for recombinant NoVs and a widely accepted recombinant genotyping system is still needed. Consequently, there is duplication in reporting of novel recombinants. This has led to difficulties in defining the number and types of recombinants in circulation. In this study, 120 NoV nucleotide sequences were compiled from the current GenBank database and published literature. NoV recombinants and their recombination breakpoints were identified using three methods: phylogenetic analysis, SimPlot analysis and the maximum χ 2 method. A total of 20 NoV recombinant types were identified in circulation worldwide. The recombination point is the ORF1/2 overlap in all isolates except one, which demonstrated a double recombination event within the polymerase region.

THE RECOMBINATION OF HUMAN ENTEROVIRUS 71

In 1998, the enterovirus (EV) infections outbreak in Taiwan caused 78 fatalities. Since then, EV infections have continuously posed a threat to the public. Among the 64 serotypes of enteroviruses known to infect human, the enterovirus 71(EV71) is suspected to be the major cause for severe cases. In this study, we estimate the recombination point of enterovirus 71 vp1 by using the method of Likelihood Analysis of Recombination in DNA. The datasets of enterovirus 71 DNA sequences are available in GenBank. After careful cross validation, eight candidate sequences are chosen to advance analysis, including 2734TAI98, TW227298, 1423SIN98 and other five DNA sequences as well. Then, the construction of the phylogeny trees (neighbor-joining trees will be used in this paper) would support for recombination in EV71 virus. In these two methods, the breakpoint was found to be in similar position, demonstrating that a single recombination event occurred prior to the divergence of these two strains.

New Natural Intergenotypic (2/5) Recombinant of Hepatitis C Virus

ABSTRACT A 9.2-kb sequence from a hepatitis C virus (HCV) strain found in southwest France was compared to sequences from reference strains in HCV sequence databases. We found a recombinant virus with genotype 2 at the 5′ end and genotype 5 at the 3′ end. The crossover point was located between genes NS2 and NS3. Recombination between HCV genotypes must now be considered in studies on HCV epidemiology and evolution and in predictions of the virus response to antiviral therapy. Knowing the location of the recombination point may also be useful for constructing infectious chimeric viruses.