165 research outputs found
"Whiter than white": interactions between optical brighteners and surfactants in detergents
The interactions between an optical brightener and surfactants commonly found in laundry detergents were studied. Three techniques were used; fluorescence spectroscopy was used to determine the effect of the addition of surfactants on the rate of brightener deposition, while small-angle X-ray scattering (SAXS) and molecular dynamics (MD) simulations were used to determine the effect of the brightener on the micellar structure pre-deposition. In addition, the effect of calcium ions on micellar structure was studied using these techniques. The effect of surfactant addition on CaCO3 crystallisation was also studied.
It was found that the addition of nonionic surfactants inhibited the deposition of brightener onto fabric surfaces, whereas the addition of anionic surfactants aided this deposition process. This was correlated to the micellar structures found using SAXS and MD simulations; the anionic surfactant system formed ellipsoidal structures, in which the brightener was incorporated onto the surface of the hydrocarbon core, whereas the nonionic surfactant formed spherical structures where the brightener was held within the outer shell, which appeared to hamper its ability to be deposited. In addition, the brightener was shown to affect micellar radius and aggregation number of the nonionic surfactant, in a manner similar to the addition of anionic surfactant to nonionic surfactant.
The addition of calcium ions at concentrations up to 0.36 g L-1 Ca2+ (for SAXS) and 0.77 g L-1 Ca2+ (for MD simulations) to nonionic and anionic surfactant systems was not seen to significantly affect their micellar structure, although a greater affinity was seen between the calcium and the anionic surfactant than between the calcium and the nonionic surfactant. The effect of the addition of surfactants on the rate of CaCO3 crystallisation and the polymorphs produced was determined
Exporting vegetables in bulk : reducing supply chain costs without compromising quality
Increased competition, a strong Australian dollar and increased production costs have seen Australian grown vegetables steadily lose their share in traditional export markets.
As competition increases, we need to investigate production and handling techniques that improve our price and quality competitiveness.
Improving the effi ciency of the supply chain to export markets is one way Australian growers can reduce production and shipping costs and improve product quality.https://researchlibrary.agric.wa.gov.au/bulletins/1121/thumbnail.jp
Nonclassical crystallization of dipicolinic acid in microemulsions
Dipicolinic acid (DPA) was crystallised in microemulsions to investigate the effect of 3D nanoconfinement on the crystallisation process. The microemulsions were acidified with 2M HCl to prevent the formation of DPA metal salts, which occurs due to a pH shift towards neutrality arising from the nanoconfinement. TEM analysis showed that 30-100 nm square-plate nanoaggregates crystallised from these acidified microemulsions. Higher resolution TEM images revealed that the nanoaggregates consisted of smaller 3-10 nm nanocrystals. The FFTās obtained from images of these nanocrystals were similar to the diffraction pattern arising from the whole nanoaggregate confirming that the nanocrystals exhibited ordered packing and resembled mesocrystals. The crystallisation of the nanoaggregates is aided by the suppression of Ostwald ripening of the nanocrystals in the nm-sized microemulsion droplets and surfactant adsorption onto the nanocrystals
Differential Hox expression in murine embryonic stem cell models of normal and malignant hematopoiesis
The Hox family are master transcriptional regulators of developmental processes, including hematopoiesis. The Hox regulators, caudal homeobox factors (Cdx1-4), and Meis1, along with several individual Hox proteins, are implicated in stem cell expansion during embryonic development, with gene dosage playing a significant role in the overall function of the integrated Hox network. To investigate the role of this network in normal and aberrant, early hematopoiesis, we employed an in vitro embryonic stem cell differentiation system, which recapitulates mouse developmental hematopoiesis. Expression profiles of Hox, Pbx1, and Meis1 genes were quantified at distinct stages during the hematopoietic differentiation process and compared with the effects of expressing the leukemic oncogene Tel/PDGFR;2. During normal differentiation the Hoxa cluster, Pbx1 and Meis1 predominated, with a marked reduction in the majority of Hox genes (27/39) and Meis1 occurring during hematopoietic commitment. Only the posterior Hoxa cluster genes (a9, a10, a11, and a13) maintained or increased expression at the hematopoietic colony stage. Cdx4, Meis1, and a subset of Hox genes, including a7 and a9, were differentially expressed after short-term oncogenic (Tel/PDGFR;2) induction. Whereas Hoxa4-10, b1, b2, b4, and b9 were upregulated during oncogenic driven myelomonocytic differentiation. Heterodimers between Hoxa7/Hoxa9, Meis1, and Pbx have previously been implicated in regulating target genes involved in hematopoietic stem cell (HSC) expansion and leukemic progression. These results provide direct evidence that transcriptional flux through the Hox network occurs at very early stages during hematopoietic differentiation and validates embryonic stem cell models for gaining insights into the genetic regulation of normal and malignant hematopoiesis
An evaluation of Independent Child Trafficking Guardians ā early adopter sites
This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated. To view this licence, visit nationalarchives.gov.uk/doc/open-government-licence/version/3This evaluation, conducted by the Home Office and the University of Bedfordshire has assessed the ICTG service in the three original early adopter sites (Greater Manchester, Hampshire, and Wales). The evaluation, conducted across a two-year period from February 2017 ā January 2019, considers the original model for the ICTG service which provided one-to-one ICTG support for all children. The overall aim of the evaluation is to answer the question:
What is the āadded valueā of the ICTG service, and is this different for different groups of children and in different early adopter sites
Teknik Proteksi Silang Untuk Pengendalian CMV Pada Krisan
. Rahardjo, I.B., E. Diningsih, and Y. Sulyo. 2008. Cross Protection Technique for Controlling CMV on Chrysanthemum. One of viru s attack chry santhemum is CMV. The alternative to control CMV is the use of vacc ine CARNA 5. The objective of the experiment was to test the cr oss protection tech nique for controlling of CMV on several chry santhemum varieties. The experiment was conduc ted in Virology Laboratory of Indonesian Ornamental Plant Research Institute (IOPRI) in Segu nung, Pacet, Cianjur , West Java, from Augu st to December 2004, using a RC BD split-plot design with 3 replications. The main plot was 5 chry santhemum varieties of White Reagent, Town Talk, Dark Fiji, Stroika, and Revert. The subplot was treatments of vacc ine and CMV, i.e. without vacc ine and CMV, CMV only, vacc ine only, and both vacc ine and CMV. The results of the experiment showed that CARNA 5 vacc ine was able to protect chry santhemum varieties of White Reagent, Town Talk, Dark Fiji, Stroika, and Revert from CMV with normal plant growth and produced good flower quality
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Reconstructing the accumulation history of a saltmarsh sediment core: which age-depth model is best?
Saltmarsh-based reconstructions of relative sea-level (RSL) change play a central role in current efforts seeking to quantify the relationship between climate and sea-level rise. The development of an accurate chronology is pivotal, since errors in age-depth relationships will propagate to the final record as alterations in both the timing and magnitude of reconstructed change. A range of age-depth modelling packages are available but differences in their theoretical basis and practical operation mean contrasting accumulation histories can be produced from the same dataset.
We compare the performance of five age-depth modelling programs (Bacon, Bchron, Bpeat, Clam and OxCal) when applied to the kinds of data used in high resolution, saltmarsh-based RSL reconstructions. We investigate their relative performance by comparing modelled accumulation curves against known age-depth relationships generated from simulated stratigraphic sequences. Bpeat is particularly sensitive to non-linearities which, whilst maximising the detection of small rate changes, has the potential to generate spurious variations, particularly in the last 400 years. Bacon generally replicates the pattern and magnitude of change but with notable offsets in timing. Bchron and OxCal successfully constrain the known accumulation history within their error envelopes although the best-fit solutions tend to underestimate the magnitude of change. The best-fit solutions of Clam generally replicate the timing and magnitude of changes well, but are sensitive to the underlying shape of the calibration curve, performing poorly where plateaus in atmospheric 14C concentration exist.
We employ an ensemble of age-depth models to reconstruct a 1500 year accumulation history for a saltmarsh core recovered from Connecticut, USA based on a composite chronology comprising 26 AMS radiocarbon dates, 210Pb, 137Cs radionuclides and an historical pollen chronohorizon. The resulting record reveals non-linear accumulation during the late Holocene with a marked increase in rate around AD1800. With the exception of the interval between AD1500 and AD1800, all modelsproduce accumulation curves that agree to within ~10 cm at the century-scale. The accumulation rate increase around AD1800 is associated with the transition from a radiocarbon-based to a 210Pb dominated chronology. Whilst repeat analysis excluding the 210Pb data alters the precise timing and magnitude of this acceleration, a shift to faster accumulation compared to the long-term rate is a robust feature of the record and not simply an artefact of the switch in dating methods. Simulation indicates that a rise of similar magnitude to the post-AD1800 increase (detrended increase of ~16 cm) is theoretically constrained and detectable within the radiocarbon-dated portion of the record. The absence of such a signal suggests that the recent rate of accumulation is unprecedented in the last 1500 years. Our results indicate that reliable (sub)century-scale age-depth models can be developed from saltmarsh sequences, and that the vertical uncertainties associated with them translate to RSL reconstruction errors that are typically smaller than those associated with the most precise microfossil-based estimates of palaeomarsh-surface elevation
Analisis Struktur Daerah Integral dari Himpunan Polinomial Berdasarkan Struktur Polinomial Gelanggang
Himpunan R[x] polinomial dengan koefisien dari gelanggang R juga merupakan sebuah gelanggang dengan berbagai operasi polinomial jumlahan dan perkalian, dan bahwa R merupakan gelanggang bagian dari R[x]. Oleh karena itu akan ditunjukkan bahwa jika D adalah sebuah daerah integral maka demikian juga dengan himpunan polinomial dengan koefisien di dalam D, yaitu D[X]
Using multiple chronometers to establish a long, directly-dated lacustrine record:Constraining >600,000 years of environmental change at Chew Bahir, Ethiopia
Despite eastern Africa being a key location in the emergence of Homo sapiens and their subsequent dispersal out of Africa, there is a paucity of long, well-dated climate records in the region to contextualize this history. To address this issue, we dated a ā¼293 m long composite sediment core from Chew Bahir, south Ethiopia, using three independent chronometers (radiocarbon, 40Ar/39Ar, and optically stimulated luminescence) combined with geochemical correlation to a known-age tephra. The site is located in a climatically sensitive region, and is close to Omo Kibish, the earliest documented Homo sapiens fossil site in eastern Africa, and to the proposed dispersal routes for H. sapiens out of Africa. The 30 ages generated by the various techniques are internally consistent, stratigraphically coherent, and span the full range of the core depth. A Bayesian age-depth model developed using these ages results in a chronology that forms one of the longest independently dated, high-resolution lacustrine sediment records from eastern Africa. The chronology illustrates that any record of environmental change preserved in the composite sediment core from Chew Bahir would span the entire timescale of modern human evolution and dispersal, encompassing the time period of the transition from Acheulean to Middle Stone Age (MSA), and subsequently to Later Stone Age (LSA) technology, making the core well-placed to address questions regarding environmental change and hominin evolutionary adaptation. The benefits to such studies of direct dating and the use of multiple independent chronometers are discussed.
Highlights
ā¢ Four independent dating methods applied to ā¼293 m lake core from southern Ethiopia.
ā¢ Reveals 620 ka high-resolution sedimentary record near key fossil hominin sites.
ā¢ Mean accumulation rate of 0.47 mm/a comparable to other African lacustrine sediments.
ā¢ Accumulation rate fell to 0.1 mm/a during MIS 2, likely due to reduced sediment supply.
ā¢ Use of multiple independent chronometers is a powerful approach in lake settings
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