310 research outputs found

    Performance and Emission Analysis of a Diesel Engine Using Linseed Biodiesel Blends

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    The core object of this study is to examine the suitability of linseeds for biodiesel production. The performance of an engine at different proportions of linseed blends with petro-diesel and the amount of emissions rate were investigated. Initially, linseed biodiesel was produced through transesterification process, and then it was mixed with petro-diesel fuel (D100) blends at volumetric ratios of 10% (LB10), 20% (LB20), and 30% (LB30). The properties of linseed biodiesel and its blends were investigated and compared with petro-diesel properties with reference to ASTM standards. It has been observed that the fuel properties of produced biodiesel are within ASTM permissible limits. The specific fuel consumption (SFC) of LB10 blend has been found lesser compared to LB20 and LB30. SFC of D100 is slightly less than that of all the blends. The brake thermal efficiency (BTE) of LB30 is greater than that of pure diesel D100 at maximum load and greater than that of LB10 and LB20. The heat dissipation rate in all linseed blends is found to have been less than that of D100. Carbon monoxide, carbon dioxide and NOx emissions of linseed blends are mostly lower in comparison with D100’s. Among all blends, LB10 was found more suitable alternative fuel for diesel engines and can be blended with petro diesel without engine modifications. It can be concluded that cultivation and production of linseed in Pakistan is very promising, therefore, it is recommended that proper exploitation and use of linseed for energy production may be encouraged through pertinent agencies of Pakistan

    Social presence and dishonesty in retail

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    Self-service checkouts (SCOs) in retail can benefit consumers and retailers, providing control and autonomy to shoppers independent from staff, together with reduced queuing times. Recent research indicates that the absence of staff may provide the opportunity for consumers to behave dishonestly, consistent with a perceived lack of social presence. This study examined whether a social presence in the form of various instantiations of embodied, visual, humanlike SCO interface agents had an effect on opportunistic behaviour. Using a simulated SCO scenario, participants experienced various dilemmas in which they could financially benefit themselves undeservedly. We hypothesised that a humanlike social presence integrated within the checkout screen would receive more attention and result in fewer instances of dishonesty compared to a less humanlike agent. This was partially supported by the results. The findings contribute to the theoretical framework in social presence research. We concluded that companies adopting self-service technology may consider the implementation of social presence in technology applications to support ethical consumer behaviour, but that more research is required to explore the mixed findings in the current study.<br/

    Concerted Action of Two Formins in Gliding Motility and Host Cell Invasion by Toxoplasma gondii

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    The invasive forms of apicomplexan parasites share a conserved form of gliding motility that powers parasite migration across biological barriers, host cell invasion and egress from infected cells. Previous studies have established that the duration and direction of gliding motility are determined by actin polymerization; however, regulators of actin dynamics in apicomplexans remain poorly characterized. In the absence of a complete ARP2/3 complex, the formin homology 2 domain containing proteins and the accessory protein profilin are presumed to orchestrate actin polymerization during host cell invasion. Here, we have undertaken the biochemical and functional characterization of two Toxoplasma gondii formins and established that they act in concert as actin nucleators during invasion. The importance of TgFRM1 for parasite motility has been assessed by conditional gene disruption. The contribution of each formin individually and jointly was revealed by an approach based upon the expression of dominant mutants with modified FH2 domains impaired in actin binding but still able to dimerize with their respective endogenous formin. These mutated FH2 domains were fused to the ligand-controlled destabilization domain (DD-FKBP) to achieve conditional expression. This strategy proved unique in identifying the non-redundant and critical roles of both formins in invasion. These findings provide new insights into how controlled actin polymerization drives the directional movement required for productive penetration of parasites into host cells

    High levels of T lymphocyte activation in Leishmania-HIV-1 co-infected individuals despite low HIV viral load

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    <p>Abstract</p> <p>Background</p> <p>Concomitant infections may influence HIV progression by causing chronic activation leading to decline in T-cell function. In the Americas, visceral (AVL) and tegumentary leishmaniasis (ATL) have emerged as important opportunistic infections in HIV-AIDS patients and both of those diseases have been implicated as potentially important co-factors in disease progression. We investigated whether leishmaniasis increases lymphocyte activation in HIV-1 co-infected patients. This might contribute to impaired cellular immune function.</p> <p>Methods</p> <p>To address this issue we analyzed CD4<sup>+ </sup>T absolute counts and the proportion of CD8<sup>+ </sup>T cells expressing CD38 in <it>Leishmania</it>/HIV co-infected patients that recovered after anti-leishmanial therapy.</p> <p>Results</p> <p>We found that, despite clinical remission of leishmaniasis, AVL co-infected patients presented a more severe immunossupression as suggested by CD4<sup>+ </sup>T cell counts under 200 cells/mm<sup>3</sup>, differing from ATL/HIV-AIDS cases that tends to show higher lymphocytes levels (over 350 cells/mm<sup>3</sup>). Furthermore, five out of nine, AVL/HIV-AIDS presented low CD4<sup>+ </sup>T cell counts in spite of low or undetectable viral load. Expression of CD38 on CD8<sup>+ </sup>T lymphocytes was significantly higher in AVL or ATL/HIV-AIDS cases compared to HIV/AIDS patients without leishmaniasis or healthy subjects.</p> <p>Conclusions</p> <p><it>Leishmania </it>infection can increase the degree of immune system activation in individuals concomitantly infected with HIV. In addition, AVL/HIV-AIDS patients can present low CD4<sup>+ </sup>T cell counts and higher proportion of activated T lymphocytes even when HIV viral load is suppressed under HAART. This fact can cause a misinterpretation of these laboratorial markers in co-infected patients.</p

    ADP-Ribosylation Factor 6 Expression and Activation Are Reduced in Myometrium in Complicated Pregnancies

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    ARF6 (ADP-ribosylation factor 6) small GTP binding protein plays critical roles in actin cytoskeleton rearrangements and membrane trafficking, including internalisation of G protein coupled receptors (GPCR). ARF6 operates by cycling between GDP-bound (inactive) and GTP-bound (active) forms and is a potential regulator of GPCR-mediated uterine activity during pregnancy and labour. ARF6 contains very low intrinsic GTP binding activity and depends on GEFs (guanine nucleotide exchange factors) such as CYTH3 (cytohesin 3) to bind GTP. ARF6 and CYTH3 were originally cloned from human placenta, but there is no information on their expression in other reproductive tissues.The expression of ARF6, ARF1, and CYTH1-4 was investigated by measuring mRNA (using RT-PCR) and protein levels (using immunoblotting) in samples of myometrium obtained from non-pregnant women, and women with normal pregnancies, before or after the spontaneous onset of labour. We also analysed myometrial samples from women with spontaneous preterm labour and from women with complicated pregnancies requiring emergency preterm delivery. The GST)-effector pull down assay was used to study the presence of active ARF6 and ARF1 in all myometrial extracts.ARF6, ARF1 and CYTH3 but not CYTH1, CYTH2 and CYTH4 were expressed in all samples and the levels did not change with pregnancy or labour. However, ARF6 and CYTH3 but not ARF1 levels were significantly reduced in complicated pregnancies. The alterations in the expression of ARF6 and its GEF in human myometrium indicate a potential involvement of this signalling system in modulating the response of myometrial smooth muscle in complicated pregnancies. The levels of ARF6-GTP or ARF1-GTP did not change with pregnancy or labour but ARF6-GTP levels were significantly decreased in women with severe complications of pregnancy.We have demonstrated a functional ARF6 system in human myometrium and a correlation between ARF6 level and activity in uterine and abnormal pregnancy
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