On fractional order models for Hepatitis C

In this paper we present a fractional order generalization of Perelson et al. basic hepatitis C virus (HCV) model including an immune response term. We argue that fractional order equations are more suitable than integer order ones in modeling complex systems which include biological systems. The model is presented and discussed. Also we argue that the added immune response term represents some basic properties of the immune system and that it should be included to study longer term behavior of the disease

Carbon monoxide intoxication from domestic fuel-burning furncaces and appliances

The aim of this research paper is to determine if dwellers of rural areas who cook using fuel-burning furnaces and appliances such as woods, charcoal and natural gas are exposed to carbon monoxide (CO) intoxication and to measure the extent of CO intoxication on dwellers resulting from their cooking activities. The data on CO concentration and health problems for this research study were gathered through the means of observation and interview. Samplings were also carried out to measure the CO level at the selected areas, which were identified based on the criteria of the research. These two steps were done concurrently. The measurements of CO in the houses at Kampong Orang Asli Simpang Arang, Gelang Patah residential were taken outside of the houses, inside the kitchen areas before switching the stove on, after the stove was switched on, during the cooking process and after the cooking was completed. The study shows that the dwellers of rural areas who cook using woods as cooking fuels are found to be exposed to CO intoxication and the factors that influence the health risks are duration of cooking activities per meal, frequency of cooking activities, the absence of proper ventilation as well as the amount of CO concentration released during cooking activities. The measured CO concentration from woods during the experiment was in the range of 150 to 500 ppm. Through CO samplings of charcoal and natural gas as control experiments, it is also found that both sources did not contribute to any serious health effects to the people using them as cooking fuels. Meanwhile, the average CO toxicant produced from burning woods was the highest and this indicates that the CO level from woods is the most risky one among the other domestic fuels commonly used

Spatio-temporal analysis of PM10 in Southern Peninsular Malaysia

In this study, the particulate matter with diameter less than 10 micrometers (PM10 ) is being observed. Other factors that influenced the pollutant dispersion are also being studied prior to identification of their relationsh ip. The aim of this study is to identify the trend of PM10 concentrations in the Southern Peninsular of Malaysia during the peri od 2005 to 2015 by using spatio-temporal analysis in regards to air pollution. The inverse distance weighted (IDW) is used for the spati o interpolation data and mapping. The trends of the PM10 concentration are illustrated via map which indicates the affected and vulnerabl e area of Southern Peninsular Malaysia especially during Haze episode

The Discovery of New Galaxy Members in the NGC 5044 and NGC 1052 Groups

We present the results of neutral hydrogen (HI) observations of the NGC 5044 and NGC 1052 groups, as part of a GEMS (Group Evolution Multiwavelength Study) investigation into the formation and evolution of galaxies in nearby groups. Two new group members have been discovered during a wide-field HI imaging survey conducted using the ATNF Parkes telescope. These results, as well as those from followup HI synthesis and optical imaging, are presented here. J1320-1427, a new member of the NGC 5044 Group, has an HI mass of M_HI=1.05e9Msun and M_HI/L_B=1.65 Msun/Lsun, with a radial velocity of v=2750km/s. The optical galaxy is characterised by two regions of star formation, surrounded by an extended, diffuse halo. J0249-0806, the new member of the NGC 1052 Group, has M_HI=5.4e8Msun, M_HI/L_R=1.13 Msun/Lsun and v=1450km/s. The optical image reveals a low surface brightness galaxy. We interpret both of these galaxies as irregular type, with J0249-0806 possibly undergoing first infall into the NGC 1052 group.Comment: Accepted for publication in MNRAS. 21 pages, 13 figures. Also available with high-resolution figures at http://www.astro.livjm.ac.uk/~npfm/Papers/mmb04.ps.g

Galaxy interactions - poor starburst triggers

We report on a study of tidally triggered star formation in galaxies, based on spectroscopic/photometric observations in the optical/near-IR of a magnitude limited sample of 59 systems of interacting and merging galaxies and a comparison sample of 38 normal isolated galaxies. In contrast to results from previous investigations, our global UBV colours do not support a significant enhancement of starforming activity in the interacting/merging galaxies. We claim that this is true also for Arp galaxies. A moderate increase in star formation is found in the very centres of the interacting galaxies contributing marginally to the total luminosity. The interacting and in particular the merging galaxies are characterized by increased far infrared (hereafter FIR) luminosities and temperatures that weakly correlate with the central activity. The L(FIR)/L(B) ratio however, is remarkably similar in the two samples, indicating that true starbursts normally are not hiding in the central regions of the FIR luminous cases. The gas mass-to-luminosity ratio in optical-IR is practically independent of luminosity, lending further support to the paucity of true massive starburst galaxies triggered by interactions/mergers. Our conclusion is that interacting and merging galaxies, from the global star formation aspect, generally do not differ dramatically from scaled up versions of normal, isolated galaxies. No drastic change with redshift is expected.Comment: 26 pages, 23 figures, accepted for publication in Astronomy & Astrophysics; figures rescaled, typos correcte

From Biology to Mathematical Models and Back: Teaching Modeling to Biology Students, and Biology to Math and Engineering Students

We describe the development of a course to teach modeling and mathematical analysis skills to students of biology and to teach biology to students with strong backgrounds in mathematics, physics, or engineering. The two groups of students have different ways of learning material and often have strong negative feelings toward the area of knowledge that they find difficult. To give students a sense of mastery in each area, several complementary approaches are used in the course: 1) a “live” textbook that allows students to explore models and mathematical processes interactively; 2) benchmark problems providing key skills on which students make continuous progress; 3) assignment of students to teams of two throughout the semester; 4) regular one-on-one interactions with instructors throughout the semester; and 5) a term project in which students reconstruct, analyze, extend, and then write in detail about a recently published biological model. Based on student evaluations and comments, an attitude survey, and the quality of the students' term papers, the course has significantly increased the ability and willingness of biology students to use mathematical concepts and modeling tools to understand biological systems, and it has significantly enhanced engineering students' appreciation of biology

The Fueling and Evolution of AGN: Internal and External Triggers

In this chapter, I review the fueling and evolution of active galactic nuclei (AGN) under the influence of internal and external triggers, namely intrinsic properties of host galaxies (morphological or Hubble type, color, presence of bars and other non-axisymmetric features, etc) and external factors such as environment and interactions. The most daunting challenge in fueling AGN is arguably the angular momentum problem as even matter located at a radius of a few hundred pc must lose more than 99.99 % of its specific angular momentum before it is fit for consumption by a BH. I review mass accretion rates, angular momentum requirements, the effectiveness of different fueling mechanisms, and the growth and mass density of black BHs at different epochs. I discuss connections between the nuclear and larger-scale properties of AGN, both locally and at intermediate redshifts, outlining some recent results from the GEMS and GOODS HST surveys.Comment: Invited Review Chapter to appear in LNP Volume on "AGN Physics on All Scales", Chapter 6, in press. 40 pages, 12 figures. Typo in Eq 5 correcte

Hepatitis C virus envelope glycoprotein fitness defines virus population composition following transmission to a new host

Genetic variability is a hallmark of RNA virus populations. However, transmission to a new host often results in a marked decrease in population diversity. This genetic bottlenecking is observed during hepatitis C virus (HCV) transmission and can arise via a selective sweep or through the founder effect. To model HCV transmission, we utilized chimeric SCID/Alb-uPA mice with transplanted human hepatocytes and infected them with a human serum HCV inoculum. E1E2 glycoprotein gene sequences in the donor inoculum and recipient mice were determined following single-genome amplification (SGA). In independent experiments, using mice with liver cells grafted from different sources, an E1E2 variant undetectable in the source inoculum was selected for during transmission. Bayesian coalescent analyses indicated that this variant arose in the inoculum pretransmission. Transmitted variants that established initial infection harbored key substitutions in E1E2 outside HVR1. Notably, all posttransmission E1E2s had lost a potential N-linked glycosylation site (PNGS) in E2. In lentiviral pseudoparticle assays, the major posttransmission E1E2 variant conferred an increased capacity for entry compared to the major variant present in the inoculum. Together, these data demonstrate that increased envelope glycoprotein fitness can drive selective outgrowth of minor variants posttransmission and that loss of a PNGS is integral to this improved phenotype. Mathematical modeling of the dynamics of competing HCV variants indicated that relatively modest differences in glycoprotein fitness can result in marked shifts in virus population composition. Overall, these data provide important insights into the dynamics and selection of HCV populations during transmission

T- and B-cell responses to multivalent prime-boost DNA and viral vectored vaccine combinations against hepatitis C virus in non-human primates.

Immune responses against multiple epitopes are required for the prevention of hepatitis C virus (HCV) infection, and the progression to phase I trials of candidates may be guided by comparative immunogenicity studies in non-human primates. Four vectors, DNA, SFV, human serotype 5 adenovirus (HuAd5) and Modified Vaccinia Ankara (MVA) poxvirus, all expressing hepatitis C virus Core, E1, E2 and NS3, were combined in three prime-boost regimen, and their ability to elicit immune responses against HCV antigens in rhesus macaques was explored and compared. All combinations induced specific T-cell immune responses, including high IFN-γ production. The group immunized with the SFV+MVA regimen elicited higher E2-specific responses as compared with the two other modalities, while animals receiving HuAd5 injections elicited lower IL-4 responses as compared with those receiving MVA. The IFN-γ responses to NS3 were remarkably similar between groups. Only the adenovirus induced envelope-specific antibody responses, but these failed to show neutralizing activity. Therefore, the two novel regimens failed to induce superior responses as compared with already existing HCV vaccine candidates. Differences were found in response to envelope proteins, but the relevance of these remain uncertain given the surprisingly poor correlation with immunogenicity data in chimpanzees, underlining the difficulty to predict efficacy from immunology studies.This work was supported by European Union contract QLK2-CT-1999- 00356, by the Biomedical Primate Research Centre, The Netherlands, and by the Swedish Research Council. We are grateful to Alexander van den Berg for technical assistance with the ICS, to our colleagues from Animal Science Department for technical assistance and expert care of the macaques, to the participants of the European HCVacc Cluster who provided help and support, and to Thomas Darton (Oxford Vaccine Group, UK) for input and advice on the manuscript. Christine Rollier is an Oxford Martin fellow and a Jenner Insitute Investigator.This is the author accepted manuscript. The final version is available from Nature Publishing Group at https://doi.org/10.1038/gt.2016.55