151 research outputs found
Evapotranspiration Landfill Cover at Wollert, Victoria
No full textDifficulties associated with the construction and maintenance of conventional landfill barrier caps has prompted a number of alternative capping solutions. One particular example is an evapotranspiration (ET) landfill cap. These covers rely on the manipulation of water balance components rather than a barrier approach in order to minimise the infiltration of water into the landfill. The overall ET cover design philosophy and process is significantly different from that employed in the construction of conventional covers.
Currently Hanson Australia, in collaboration with Melbourne University, is working through the design and research of an ET cover at Wollert landfill in Victoria. This paper presents the background and objectives of the project, a summary of the progress to date and intended future research. An insight is given into cover material and plant selection and required field, laboratory and glasshouse trials.Full Tex
A comparative study of green composites based on tapioca starch and celluloses
No full textThe objective of this study was to compare the properties of green composites based on tapioca starch (TS) and celluloses isolated from empty fruit bunches (EFB) and commercial celluloses from cotton linter (supplied by Sigma). Empty fruit bunches (EFB) acted as the main source to obtain the cellulose by using a chemical approach whereas the commercial cellulose from Sigma was used as reference. The TS/cellulose composite films were prepared using cellulose in varying proportions as filler into TS matrix by a casting method. The amount of celluloses added into the tapioca starch were 5, 10, 15, 20 and 25 phr (as per dry mass of TS). The celluloses were characterized using Fourier transform infrared (FTTR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). While the green composite films were analyzed in terms of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), SEM and tensile properties. FTTR analysis confirmed the removal of non-cellulosic materials such as hemicelluloses and lignin from raw EFB after the chemical treatment. XRD diffractograms revealed that the crystallinity of celluloses EFB increased from 43.1 % of raw EFB to 52.1 %. SEM images showed the fibrillar structure of cellulose isolated from EFB. The TGA and derivative thermogravimetric (DTG) curves of green composite films showed no significant effect on the thermal stability. Melting temperature of TS/cellulose EFB higher than neat TS while TS/cellulose Sigma lower than neat TS. The green composite films with 15 phr cellulose from EFB filler loading provided the best tensile properties in term of its strength and modulus. However, in term of elongation at break, the percentage elongation decreased with the increased of the amount of filler loading. SEM images of the films demonstrated a good interaction between cellulose filler and TS matrix especially with the addition of 15 phr of cellulose from EFB. © 2017 Author(s)
Toward the Construction of a Kinetic Model of Methionine and Thereonine Biosynthesis to Increase Seed Nutritional Value: Characterization of Threonine Synthase.
No full textImproving the nutritional quality of crop species, like Cicer arietinum and Lens culinaris, is of particular interest to agricultural biotechnology. These crops are deficient, from a human dietary perspective, in the essential amino acid L-methionine (L-Met). In plants, the biosynthesis of L-Met is initiated by the formation of L-cystathionine from O-phospho-L-homoserine (OPHS) catalyzed by cystathionine γ-synthase (CGS). OPHS occupies the branch-point between L-Met and L-threonine (L-Thr) biosynthesis, catalyzed by threonine synthase (TS), making these two enzymes targets for metabolic engineering studies to increase L-Met production. The construction of a kinetic model recreating the branch-point can facilitate the metabolic engineering of important crop species by providing a tool for anticipating disturbances in metabolic flux caused by manipulations to the branch-point. The focus of the research described in this thesis is to provide a starting point for the creation of a kinetic model of the OPHS branch-point in the target species. The characterization of plant TS requires a continuous spectrophotometric assay, which was developed using a non-allosteric variant of threonine deaminase from Escherichia coli (eTDL447F) and hydroxyisocaproate dehydrogenase (HO-HxoDH) from Lactobacillus delbrueckii. The assay was verified for suitability for use under the various pH optima of TS across phyla. The functional coding sequences of TS from C. arietinum (CaTS) and L. culinaris (LcTS) share approximately 80% amino acid sequence identity with TS from Glycine max, and the residues of the allosteric site are conserved with those of TS from other plant species. The PLP-binding motif, which is conserved across plant and microbial species, is present in the active site of both enzymes. The kinetic parameters of CaTS, LcTS, and AtTS2 were measured with 100 µM of the allosteric activator S-adenosyl-L-methionine (SAM), with the parameters of AtTS1 measured as a control. SAM increases the kcat/KmOPHS of AtTS2, LcTS, CaTS, and AtTS1 by 10-, 20-, 25-, and 80-fold, respectively. Due to the varying flux control patterns of TS from A. thaliana, C. arietinum, and L. culinaris, the construction of a species-specific kinetic model of the branch-point is needed for future aimed at increasing L-Met biosynthesis to nutritionally significant levels
Engineering of <it>N. benthamiana </it>L. plants for production of N-acetylgalactosamine-glycosylated proteins - towards development of a plant-based platform for production of protein therapeutics with mucin type O-glycosylation
No full textAbstract Background Mucin type O-glycosylation is one of the most common types of post-translational modifications that impacts stability and biological functions of many mammalian proteins. A large family of UDP-GalNAc polypeptide:N-acetyl-α-galactosaminyltransferases (GalNAc-Ts) catalyzes the first step of mucin type O-glycosylation by transferring GalNAc to serine and/or threonine residues of acceptor polypeptides. Plants do not have the enzyme machinery to perform this process, thus restricting their use as bioreactors for production of recombinant therapeutic proteins. Results The present study demonstrates that an isoform of the human GalNAc-Ts family, GalNAc-T2, retains its localization and functionality upon expression in N. benthamiana L. plants. The recombinant enzyme resides in the Golgi as evidenced by the fluorescence distribution pattern of the GalNAc-T2:GFP fusion and alteration of the fluorescence signature upon treatment with Brefeldin A. A GalNAc-T2-specific acceptor peptide, the 113-136 aa fragment of chorionic gonadotropin β-subunit, is glycosylated in vitro by the plant-produced enzyme at the "native" GalNAc attachment sites, Ser-121 and Ser-127. Ectopic expression of GalNAc-T2 is sufficient to "arm" tobacco cells with the ability to perform GalNAc-glycosylation, as evidenced by the attachment of GalNAc to Thr-119 of the endogenous enzyme endochitinase. However, glycosylation of highly expressed recombinant glycoproteins, like magnICON-expressed E. coli enterotoxin B subunit:H. sapiens mucin 1 tandem repeat-derived peptide fusion protein (LTBMUC1), is limited by the low endogenous UDP-GalNAc substrate pool and the insufficient translocation of UDP-GalNAc to the Golgi lumen. Further genetic engineering of the GalNAc-T2 plants by co-expressing Y. enterocolitica UDP-GlcNAc 4-epimerase gene and C. elegans UDP-GlcNAc/UDP-GalNAc transporter gene overcomes these limitations as indicated by the expression of the model LTBMUC1 protein exclusively as a glycoform. Conclusion Plant bioreactors can be engineered that are capable of producing Tn antigen-containing recombinant therapeutics.</p
An extracellular steric seeding mechanism for Eph-ephrin signaling platform assembly
No full textErythropoetin-producing hepatoma (Eph) receptors are cell-surface protein tyrosine kinases mediating cell-cell communication. Upon activation, they form signaling clusters. We report crystal structures of the full ectodomain of human EphA2 (eEphA2) both alone and in complex with the receptor-binding domain of the ligand ephrinA5 (ephrinA5 RBD). Unliganded eEphA2 forms linear arrays of staggered parallel receptors involving two patches of residues conserved across A-class Ephs. eEphA2-ephrinA5 RBD forms a more elaborate assembly, whose interfaces include the same conserved regions on eEphA2, but rearranged to accommodate ephrinA5 RBD. Cell-surface expression of mutant EphA2s showed that these interfaces are critical for localization at cell-cell contacts and activation-dependent degradation. Our results suggest a 'nucleation' mechanism whereby a limited number of ligand-receptor interactions 'seed' an arrangement of receptors which can propagate into extended signaling arrays
Blind deconvolution of sparse pulse sequences under a minimum distance constraint: a partially collapsed Gibbs sampler method
No full textFor blind deconvolution of an unknown sparse sequence convolved with an unknown pulse, a powerful Bayesian method employs the Gibbs sampler in combination with a Bernoulli–Gaussian prior modeling sparsity. In this paper, we extend this method by introducing a minimum distance constraint for the pulses in the sequence. This is physically relevant in applications including layer detection, medical imaging, seismology, and multipath parameter estimation. We propose a Bayesian method for blind deconvolution that is based on a modified Bernoulli–Gaussian prior including a minimum distance constraint factor. The core of our method is a partially collapsed Gibbs sampler (PCGS) that tolerates and even exploits the strong local dependencies introduced by the minimum distance constraint. Simulation results demonstrate significant performance gains compared to a recently proposed PCGS. The main advantages of the minimum distance constraint are a substantial reduction of computational complexity and of the number of spurious components in the deconvolution result
Phytocapping of Landfills
No full textPhytocapping presents a sustainable alternative to the conventional top barrier cover design. It relies on the capacity of a porous substrate (usually of locally available soil) to store water together with the natural processes of surface evaporation and plant transpiration to remove the stored water as a means of controlling water ingress into the landfill. This chapter is based on the Australian experience in researching and implementing phytocaps as final covers for municipal waste landfills. In 2006, the Australian Alternative Cover Assessment Program (A-ACAP) was established to compare the performance (in terms of drainage, landfill gas, and plant growth) of phytocapping against traditional compacted clay barrier caps. The trials showed that phytocapping has the potential to reduce drainage as effectively as compacted clay barrier caps and in a more predictable manner; to oxidize fugitive methane emissions more effectively than barrier caps; and to enable more variable and sustainable vegetation communities to be established. Guidelines published as an outcome of the A-ACAP have been adopted in Australia as a basis for design and are being referenced in regulatory guidance as they are reviewed and updated. Phytocapping has now been approved and constructed in all mainland States (with the exception of Western Australia, where construction is due to commence shortly). The full-scale experience has shown that phytocapping is an alternative to conventional barrier caps but requires specialized input into design and different techniques for construction and maintenance to ensure its continued performance.No Full Tex
The ascension, pleroma and ecclesia concepts in Ephesians
No full textThe basic aim of the study is to investigate
the relationship between a number of christological
and ecclesiological themes. The first section of the
essay is concerned with the identification of the
traditions employed by the author in his presentation
of an ascension theology in 1:20-23 and 4:8-10.
Having once established these traditions, an attempt
is made to trace a Traditiongeschichte for them.
The second part of the essay is concerned with the
relationship between the ascension theology and the
kephale and pleroma motifs which are present in both
pericopes. This investigation necessitates an
examination of the Pauline theology. At the same
time within this section an attempt is made to trace
the source of the pleroma terminology as used by the
author of the epistle. In the third section of the
essay the interest is more general; an attempt is
made to discover how the "component parts" of the
author's ascension theology are used elsewhere in the
epistle. In the fourth and last section of the essay
the interest is again with traditions, specifically
the use made of the traditions inherent in the
ascension pericopes in the epistle in the writings
of both the Church Fathers and of authors outside
the main stream of Christian thought
South African travel writing and bias
No full textIncludes bibliographical references (leaves 92-96).This thesis spotlights the travel and leisure magazine industry within South Africa. It contends that the travel writing genre is susceptible to a number of biases, both past and present, which ultimately affect the way its overall content is produced and presented to the public. This work was substantiated through a set of qualitative interviews with key professionals within the South African travel and leisure magazine industry, as well as through a theme- based content analysis of a number of local travel writing publications. This study adds to a rather extensive line of research written on the topic of travel writing regarding a number of older criticisms of bias including 'othering', escapism, and gendering. However, it also focuses on a number of more modem biases such as direct advertising, advertorial usage, as well as the acceptance of 'freebies' and barter agreements, none of which has been given much attention in previous research. The sheer existence of these and other biases within the modem South African travel and leisure magazine industry exhibits an absolute necessity of examination into such a topic, especially given the importance and overall influence that the travel writing industry has on a country's economic standing and overall image
Mood instability, mental illness and suicidal ideas : results from a household survey
No full textPurpose:
There is weak and inconsistent evidence that mood instability (MI) is associated with depression, post traumatic stress disorder (PTSD) and suicidality although the basis of this is unclear. Our objectives were first to test whether there is an association between depression and PTSD, and MI and secondly whether MI exerts an independent effect on suicidal thinking over and above that explained by common mental disorders.
Methods:
We used data from the Adult Psychiatric Morbidity Survey 2007 (N = 7,131). Chi-square tests were used to examine associations between depression and PTSD, and MI, followed by regression modelling to examine associations between MI and depression, and with PTSD. Multiple logistic regression analyses were used to assess the independent effect of MI on suicidal thinking, after adjustment for demographic factors and the effects of common mental disorder diagnoses.
Results:
There are high rates of MI in depression and PTSD and the presence of MI increases the odds of depression by 10.66 [95 % confidence interval (CI) 7.51–15.13] and PTSD by 8.69 (95 % CI 5.90–12.79), respectively, after adjusting for other factors. Mood instability independently explained suicidal thinking, multiplying the odds by nearly five (odds ratio 4.82; 95 % CI 3.39–6.85), and was individually by some way the most important single factor in explaining suicidal thoughts.
Conclusions:
MI is strongly associated with depression and PTSD. In people with common mental disorders MI is clinically significant as it acts as an additional factor exacerbating the risk of suicidal thinking. It is important to enquire about MI as part of clinical assessment and treatment studies are required
- …
