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1.
Sci Rep ; 14(1): 15171, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38956417

ABSTRACT

We present the first machine learning-based autonomous hyperspectral neutron computed tomography experiment performed at the Spallation Neutron Source. Hyperspectral neutron computed tomography allows the characterization of samples by enabling the reconstruction of crystallographic information and elemental/isotopic composition of objects relevant to materials science. High quality reconstructions using traditional algorithms such as the filtered back projection require a high signal-to-noise ratio across a wide wavelength range combined with a large number of projections. This results in scan times of several days to acquire hundreds of hyperspectral projections, during which end users have minimal feedback. To address these challenges, a golden ratio scanning protocol combined with model-based image reconstruction algorithms have been proposed. This novel approach enables high quality real-time reconstructions from streaming experimental data, thus providing feedback to users, while requiring fewer yet a fixed number of projections compared to the filtered back projection method. In this paper, we propose a novel machine learning criterion that can terminate a streaming neutron tomography scan once sufficient information is obtained based on the current set of measurements. Our decision criterion uses a quality score which combines a reference-free image quality metric computed using a pre-trained deep neural network with a metric that measures differences between consecutive reconstructions. The results show that our method can reduce the measurement time by approximately a factor of five compared to a baseline method based on filtered back projection for the samples we studied while automatically terminating the scans.

2.
Nat Commun ; 14(1): 605, 2023 Feb 04.
Article in English | MEDLINE | ID: mdl-36739274

ABSTRACT

Recent experiments on kagome metals AV3Sb5 (A=K,Rb,Cs) identify twofold van Hove singularities (TvHS) with opposite concavity near the Fermi energy, generating two approximately hexagonal Fermi surfaces - one electron-like and the other hole-like. Here we propose that a TvHS generates a novel time-reversal symmetry breaking excitonic order - arising due to bound pairs of electrons and holes located at opposite concavity van Hove singularities. We introduce a minimal model for the TvHS and investigate interaction induced many-body instabilities via the perturbative renormalisation group technique and a free energy analysis. Specialising to parameters appropriate for the kagome metals AV3Sb5, we construct a phase diagram comprising chiral excitons, charge density wave and a region of coexistence. We propose this as an explanation of a diverse range of experimental observations in AV3Sb5. Notably, the chiral excitonic state gives rise to a quantum anomalous Hall conductance, providing an appealing interpretation of the observed anomalous Hall effect in kagome metals. Possible alternative realisations of the TvHS mechanism in bilayer materials are also discussed. We suggest that TvHS open up interesting possibilities for correlated phases, enriching the set of competing ground states to include excitonic order.

3.
Phys Rev Lett ; 130(6): 066001, 2023 Feb 10.
Article in English | MEDLINE | ID: mdl-36827571

ABSTRACT

We theoretically study a moiré superlattice geometry consisting of mirror-symmetric twisted trilayer graphene surrounded by identical transition metal dichalcogenide layers. We show that this setup allows us to switch on or off and control the spin-orbit splitting of the Fermi surfaces via application of a perpendicular displacement field D_{0} and explore two manifestations of this control: first, we compute the evolution of superconducting pairing with D_{0}; this features a complex admixture of singlet and triplet pairing and, depending on the pairing state in the parent trilayer system, phase transitions between competing superconducting phases. Second, we reveal that, with application of D_{0}, the spin-orbit-induced spin textures exhibit vortices which lead to "Möbius fermi surfaces" in the interior of the Brillouin zone: diabatic electron trajectories, which are predicted to dominate quantum oscillation experiments, require encircling the Γ point twice, making their Möbius nature directly observable. Further, we show that the superconducting order parameter inherits the unconventional, Möbius spin textures. Our findings suggest that this system provides a promising experimental avenue for systematically studying the impact of spin-orbit coupling on the multitude of topological and correlated phases in near-magic-angle twisted trilayer graphene.

4.
Sci Rep ; 12(1): 14318, 2022 08 22.
Article in English | MEDLINE | ID: mdl-35996007

ABSTRACT

The objective of Trial 1 was to determine the effects of condensed tannins (CT) from sericea lespedeza [SL; Lespedeza cuneata (Dum. Cours.) G. Don] on in vitro digestible organic matter (IVDOM), total gas production (GP), methane (CH4) emission, and ruminal fluid parameters after fermentation. Substrates used in four 48-h in vitro fermentations were 100% bermudagrass [(Cynodon dactylon (L.) Pers.] hay (0SL), 100% SL hay (100SL), and a mix of both hays (50SL). Linear reductions were observed for all parameters (P < 0.05) with the inclusion of SL, except for CH4 in relation to GP, that presented a quadratic effect (P = 0.005). In Trial 2, SL plants were enriched with 13C-CO2 to obtain pure enriched CT to identify the destination of fermentation end products of CT degradation. The enrichment of CT through the SL was successful (P < 0.001), and carbon originated from CT was detected in the fermentation end products [microbial mass, clarified rumen fluid, and in the CH4 produced (P < 0.001)]. Therefore, inclusion of SL was effective in reducing in vitro CH4 production and compound-specific tracing of δ13C abundance provided better quantitative understanding of the mechanisms of partitioning CT during ruminal fermentation processes.


Subject(s)
Lespedeza , Proanthocyanidins , Animal Feed/analysis , Animals , Diet , Fermentation , Goats/metabolism , Isotopes/metabolism , Methane/metabolism , Proanthocyanidins/pharmacology , Rumen/metabolism
5.
Sci Rep ; 12(1): 14220, 2022 08 20.
Article in English | MEDLINE | ID: mdl-35987790

ABSTRACT

The objectives of this study were to determine the emission of nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), as well as the isotopic composition of N2O from excreta of beef steers fed 'AU Grazer' sericea lespedeza hay [SL; Lespedeza cuneata (Dum. Cours.) G. Don]. Fifteen Brahman × Angus crossbred steers were fed one of three experimental diets: 0, 50, or 100% inclusion of SL into 'Tifton 85' bermudagrass hay (Cynodon spp.). Gas sampling occurred on days 0, 1, 3, 5, 7, 14, 18, 25, and 32 after urine or feces application to static chambers for two experimental periods. Effect of the day after feces application (P < 0.001), while day × inclusion of SL interaction was observed in urine (P < 0.001) for all greenhouse gases (GHG) analyzed. Peaks of emission of all GHG in urine and feces occurred in the first days (P < 0.001), with days 3 and 5 being most depleted in 15N-N2O in feces, and days 3, 5, and 7, in urine (P < 0.001). Feeding SL to beef steers was effective in mitigating the emission of GHG from the excreta, but further research is necessary to investigate the mechanisms behind the reductions.


Subject(s)
Fabaceae , Greenhouse Gases , Lespedeza , Animal Feed/analysis , Animals , Cattle , Diet/veterinary , Methane , Nitrous Oxide , Tannins , Vegetables
6.
J Inorg Biochem ; 225: 111598, 2021 12.
Article in English | MEDLINE | ID: mdl-34517168

ABSTRACT

Silver is commonly included in a range of household and medical items to provide bactericidal action. Despite this, the chemical fate of the metal in both mammalian and bacterial systems remains poorly understood. Here, we applied a metallomics approach using X-ray absorption spectroscopy (XAS) and size-exclusion chromatography hyphenated with inductively coupled plasma mass spectrometry (SEC-ICP-MS) to advance our understanding of the biochemical fate of silver ions in bacterial culture and cells, and the chemistry associated with these interactions. When silver ions were added to lysogeny broth, silver was exclusively associated with moderately-sized species (~30 kDa) and bound by thiolate ligands. In two representative bacterial pathogens cultured in lysogeny broth including sub-lethal concentrations of ionic silver, silver was found in cells to be predominantly coordinated by thiolate species. The silver biomacromolecule-binding profile in Staphylococcus aureus and Escherichia coli was complex, with silver bound by a range of species spanning from 20 kDa to >1220 kDa. In bacterial cells, silver was nonuniformly colocalised with copper-bound proteins, suggesting that cellular copper processing may, in part, confuse silver for nutrient copper. Notably, in the treated cells, silver was not detected bound to low molecular weight compounds such as glutathione or bacillithiol.


Subject(s)
Anti-Bacterial Agents/metabolism , Escherichia coli/metabolism , Silver/metabolism , Staphylococcus aureus/metabolism , Anti-Bacterial Agents/chemistry , Chromatography, Gel , Mass Spectrometry , Metabolomics , Silver/chemistry , Sulfur/chemistry , X-Ray Absorption Spectroscopy
7.
J Anim Sci ; 99(8)2021 Aug 01.
Article in English | MEDLINE | ID: mdl-34333648

ABSTRACT

An experiment was conducted to evaluate the effects of different proportions of 'Au Grazer' sericea lespedeza [SL, Lespedeza cuneata (Dum. Cours.) G. Don], a legume rich in condensed tannins (CT), on nutrient intake and digestibility, and to estimate methane (CH4) emissions and 13C isotopic composition (δ13CCH4) from beef steers consuming a forage-based diet. Twenty-five Angus-crossbred steers were distributed in a randomized complete block design (344 ± 48 kg initial BW), and randomly assigned to one of five treatments: 0SL, 25SL, 50SL, 75SL, and 100SL, diets containing 0%, 25%, 50%, 75%, and 100% of SL hay, respectively, mixed with 'Tifton-85' bermudagrass hay (Cynodon spp.). The study was carried out for two experimental periods of 21-d each. The statistical model included the fixed effect of treatment and random effects of block, experimental period, and their interaction. Apparent total tract digestibility of crude protein, neutral detergent fiber, and acid detergent fiber was linearly decreased (P < 0.001) by the inclusion of SL. No effects were observed for total CH4 emissions per day, nor for CH4 relative to organic matter intake or digestible organic matter with the inclusion of SL. However, emission of CH4 in relation to intake of CT was affected by treatment (P < 0.001). A linear (P < 0.001) decrease and a quadratic effect (P < 0.001) were observed for δ13C of diets and gas, respectively, in which diets and enteric CH4 with greater inclusion of SL were more depleted in 13C. Moreover, the difference in δ13C between diets and gas (Δδ13C) had a linear decrease (P = 0.001) with the inclusion of SL. The model developed to predict the C3 proportions in the enteric CH4 fitted to predicted values (P < 0.0001). Therefore, greater proportions of SL resulted in lesser CH4 emission when CT intake was considered and the isotopic composition from enteric CH4 was able to predict the contribution of SL in the emissions.


Subject(s)
Lespedeza , Animal Feed/analysis , Animals , Cattle , Cynodon , Diet/veterinary , Digestion , Methane , Rumen
8.
Front Vet Sci ; 8: 628445, 2021.
Article in English | MEDLINE | ID: mdl-33748210

ABSTRACT

This review provides an update of ecologically relevant phytochemicals for ruminant production, focusing on their contribution to advancing nutrition. Phytochemicals embody a broad spectrum of chemical components that influence resource competence and biological advantage in determining plant species' distribution and density in different ecosystems. These natural compounds also often act as plant defensive chemicals against predatorial microbes, insects, and herbivores. They may modulate or exacerbate microbial transactions in the gastrointestinal tract and physiological responses in ruminant microbiomes. To harness their production-enhancing characteristics, phytochemicals have been actively researched as feed additives to manipulate ruminal fermentation and establish other phytochemoprophylactic (prevent animal diseases) and phytochemotherapeutic (treat animal diseases) roles. However, phytochemical-host interactions, the exact mechanism of action, and their effects require more profound elucidation to provide definitive recommendations for ruminant production. The majority of phytochemicals of nutritional and pharmacological interest are typically classified as flavonoids (9%), terpenoids (55%), and alkaloids (36%). Within flavonoids, polyphenolics (e.g., hydrolyzable and condensed tannins) have many benefits to ruminants, including reducing methane (CH4) emission, gastrointestinal nematode parasitism, and ruminal proteolysis. Within terpenoids, saponins and essential oils also mitigate CH4 emission, but triterpenoid saponins have rich biochemical structures with many clinical benefits in humans. The anti-methanogenic property in ruminants is variable because of the simultaneous targeting of several physiological pathways. This may explain saponin-containing forages' relative safety for long-term use and describe associated molecular interactions on all ruminant metabolism phases. Alkaloids are N-containing compounds with vast pharmacological properties currently used to treat humans, but their phytochemical usage as feed additives in ruminants has yet to be exploited as they may act as ghost compounds alongside other phytochemicals of known importance. We discussed strategic recommendations for phytochemicals to support sustainable ruminant production, such as replacements for antibiotics and anthelmintics. Topics that merit further examination are discussed and include the role of fresh forages vis-à-vis processed feeds in confined ruminant operations. Applications and benefits of phytochemicals to humankind are yet to be fully understood or utilized. Scientific explorations have provided promising results, pending thorough vetting before primetime use, such that academic and commercial interests in the technology are fully adopted.

9.
Metallomics ; 13(1)2021 01 16.
Article in English | MEDLINE | ID: mdl-33570135

ABSTRACT

The antibacterial properties of silver have been known for centuries and the threat of antibiotic-resistant bacteria has led to renewed focus on the noble metal. Silver is now commonly included in a range of household and medical items to imbue them with bactericidal properties. Despite this, the chemical fate of the metal in biological systems is poorly understood. Silver(I) is a soft metal with high affinity for soft donor atoms and displays much similarity to the chemistry of Cu(I). In bacteria, interaction of silver with the cell wall/membrane, DNA, and proteins and enzymes can lead to cell death. Additionally, the intracellular generation of reactive oxygen species by silver is posited to be a significant antimicrobial action. While the antibacterial action of silver is well known, bacteria found in silver mines display resistance against it through use of a protein ensemble thought to have been specifically developed for the metal, highlighting the need for judicious use. In mammals, ∼10-20% of ingested silver is retained by the body and thought to predominantly localize in the liver or kidneys. Chronic exposure can result in argyria, a condition characterized by blue staining of the skin, resulting from subdermal deposition of silver [as Ag(0)/sulfides], but more insidious side effects, such as inclusions in the brain, seizures, liver/kidney damage, and immunosuppression, have also been reported. Here, we hope to highlight the current understanding of the biological chemistry of silver and the necessity for continued study of these systems to fill existing gaps in knowledge.


Subject(s)
Silver/pharmacology , Animals , Anti-Bacterial Agents/adverse effects , Anti-Bacterial Agents/pharmacokinetics , Anti-Bacterial Agents/pharmacology , Cell Wall/drug effects , DNA/drug effects , Humans , Kidney/metabolism , Liver/metabolism , Microbial Sensitivity Tests , Proteins/drug effects , Reactive Oxygen Species/metabolism , Silver/adverse effects , Silver/pharmacokinetics
10.
Molecules ; 25(19)2020 Oct 04.
Article in English | MEDLINE | ID: mdl-33020442

ABSTRACT

Silver(I)-based coordination polymers or metal-organic frameworks (MOFs) display useful antibacterial properties, whereby distinct materials with different bonding can afford control over the release of silver(I) ions. Such silver(I) materials are comprised of discrete secondary building units (SBUs), and typically formed with ligands possessing only soft or borderline donors. We postulated that a linker with four potential donor groups, comprising carboxylate and soft thioether donors, 2,5-bis (allylsulfanyl) benzene dicarboxylic acid (ASBDC), could be used to form stable, highly connected coordination polymers with silver(I). Here, we describe the synthesis of a new material, (Ag2(ASBDC)), which possesses a rod-like metal node-based 3D honeycomb structure, strongly -stacked linkers, and steric bulk to protect the node. Due to the rod-like metal node and the blocking afforded by the ordered allyl groups, the material displays notable thermal and moisture stability. An interesting structural feature of (Ag2(ASBDC)) is contiguous Ag-S bonding, essentially a helical silver chalcogenide wire, which extends through the structure. These interesting structural features, coupled with the relative ease by which MOFs made with linear dicarboxylate linkers can be reticulated, suggests this may be a structure type worthy of further investigation.


Subject(s)
Anti-Bacterial Agents/chemistry , Coordination Complexes , Dicarboxylic Acids/chemistry , Polymers , Silver/chemistry , Coordination Complexes/chemical synthesis , Coordination Complexes/chemistry , Polymers/chemical synthesis , Polymers/chemistry
11.
J Anim Sci ; 98(7)2020 Jul 01.
Article in English | MEDLINE | ID: mdl-32674157

ABSTRACT

Achieving high animal productivity without degrading the environment is the primary target in pasture-based dairy farming. This study investigated the effects of changing the forage base in spring from grass-clover pastures to forb or legume-based pastures on milk yield, N utilization, and methane emissions of Jersey cows in Western Oregon. Twenty-seven mid-lactation dairy cows were randomly assigned to one of three pasture treatments: grass-clover-based pasture composed of festulolium, tall fescue, orchardgrass, and white clover (Grass); forb-based pasture composed of chicory, plantain, and white clover (Forb); and legume-based pasture composed of red clover, bird's-foot trefoil, berseem clover, and balansa clover (Legume). Pastures were arranged in a randomized complete block design with three replicates (i.e., blocks) with each replicate grazed by a group of three cows. Production and nutritive quality of the forages, animal performance, milk components, nitrogen partitioning, and methane emissions were measured. Feed quality and dry matter intake (DMI) of cows were greater (P ≤ 0.05) for Legume and Forb vs. Grass, with consequent greater milk and milk solids yields (P < 0.01). Cows grazing Forb also had more (P < 0.01) lactose and linoleic acid in milk compared with cows grazing the other pastures, and less (P = 0.04) somatic cell counts compared with Grass. Cows grazing Forb had substantially less (P < 0.01) N in urine, milk, and blood compared with cows grazing the other pastures, with not only a greater (P < 0.01) efficiency of N utilization for milk synthesis calculated using milk urea nitrogen but also a larger (P < 0.01) fecal N content, indicating a shift of N from urine to feces. Both Forb and Legume had a diuretic effect on cows, as indicated by the lower (P < 0.01) creatinine concentration in urine compared with Grass. Methane emissions tended to be less (P = 0.07) in cows grazed on Forb vs. the other pastures. The results indicate that Forb pasture can support animal performance, milk quality, and health comparable to Legume pasture; however, Forb pasture provides the additional benefit of reduced environmental impact of pasture-based dairy production.


Subject(s)
Cattle/physiology , Cichorium intybus , Lactation/physiology , Medicago , Methane/biosynthesis , Poaceae , Animal Feed/analysis , Animal Nutritional Physiological Phenomena , Animals , Blood Urea Nitrogen , Cattle/metabolism , Diet/veterinary , Feces , Female , Milk/physiology , Nitrogen , Nutritive Value , Seasons
12.
J Intellect Disabil Res ; 64(1): 45-56, 2020 01.
Article in English | MEDLINE | ID: mdl-31478300

ABSTRACT

BACKGROUND: Longitudinal data on medication use in adults with intellectual disability (ID) are scarce. We describe the longitudinal use of and factors associated with psychotropic medication prescribing in adults with ID living in the Australian community. METHODS: Longitudinal data were obtained from adults with ID in the community in Queensland, Australia, between 1999 and 2015. Participant characteristics and medication use information were extracted from baseline questionnaires and health check booklets. Logistic regression was used to investigate the associations between participant characteristics and psychotropic medication use, commencement or cessation. RESULTS: Longitudinal data were available for 138 participants on 697 reviews. The proportion of participants prescribed psychotropic medications increased from 43% to 54% between 1999 and 2015. The rates of commencement and cessation of psychotropic medications between consecutive time periods ranged from 9% to 18% and 7% to 15%, respectively. Challenging behaviour was associated with psychotropic medication use (adjusted odds ratio = 4.1; 95% confidence interval: 2.1-7.9). Presence of challenging behaviour, either consistent or newly identified, was positively associated with ongoing use or commencement of psychotropic medications. CONCLUSIONS: Psychotropic medications are commonly prescribed to adults with ID. Challenging behaviour is positively associated with ongoing use and commencement.


Subject(s)
Drug Prescriptions/statistics & numerical data , Intellectual Disability/drug therapy , Problem Behavior , Psychotropic Drugs/therapeutic use , Adolescent , Adult , Aged , Cohort Studies , Humans , Longitudinal Studies , Middle Aged , Queensland , Young Adult
13.
Int J Tuberc Lung Dis ; 23(10): 1055-1059, 2019 10 01.
Article in English | MEDLINE | ID: mdl-31627769

ABSTRACT

SETTING: The main hospital tuberculosis (TB) clinic in South Tarawa, the capital of the Republic of Kiribati, a Pacific nation located in the central Pacific Ocean.OBJECTIVE: To determine if higher levels of HbA1c were associated with greater odds of TB.DESIGN: A case-control study to assess the association between TB and diabetes (DM). We recruited 275 TB cases and 498 controls (persons without signs and symptoms of TB), aged 18 years and above. A standardised questionnaire was administered and HbA1c was measured in all participants.RESULTS: The median HbA1c among cases was 6.0%; among controls it was 5.6% (P < 0.001). Comparing cases to controls, the odds ratio for TB was 2.8 (95%CI 2.0-4.1). Adjusted odds ratios for TB associated with HbA1c groupings of 5.7-6.4%, 6.5-8.5% and >8.5% were 1.5, 2.7 and 4.3, respectively (P ≦ 0.001 for trend).CONCLUSIONS: The median HbA1c was higher among TB patients than controls. As the HbA1c rose so did the odds of TB. This demonstrates the importance of targeted TB screening of people with DM in TB-endemic settings. Optimal glycaemic control is also crucial as this reduces DM-related end organ damage and may also reduce TB risk.


Subject(s)
Diabetes Mellitus/epidemiology , Glycated Hemoglobin/metabolism , Mass Screening/methods , Tuberculosis/epidemiology , Adult , Blood Glucose/metabolism , Case-Control Studies , Diabetes Mellitus/diagnosis , Female , Humans , Male , Micronesia/epidemiology , Surveys and Questionnaires , Tuberculosis/diagnosis
14.
J Anal Methods Chem ; 2019: 6164058, 2019.
Article in English | MEDLINE | ID: mdl-30944753

ABSTRACT

TOF-ND elastic scattering of thermal neutrons offers some important advantages over X-ray diffraction (XRD), X-ray fluorescence (XRF), and metallography for the study of archaeological and numismatic problems. Traditional analytical methods are usually destructive and often probe only the surface. Neutrons deeply penetrate samples, simultaneously giving nondestructive bulk information about the crystal structure, composition, and texture (alignment of crystallites) from which thermomechanical manufacturing processes (e.g., cast, struck, or rolled) may be inferred. An analysis of the metal composition and minting processes used for making ancient Judaean bronze and leaded bronze coins from first century BCE and CE is used as a case study. One of the first ND analyses of the temperature used for striking bronze coins is also presented.

15.
Rev Sci Instrum ; 89(9): 092901, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30278774

ABSTRACT

In situ neutron scattering is a powerful tool to reveal materials atomic structural response such as phase transformation, lattice straining, and texture under external stimuli. The advent of a high flux neutron source such as the Spallation Neutron Source (SNS) allows fast measurement in even non-equilibrium conditions, i.e., phase transformation in steels. However, the commercial fast heating apparatus such as commercial physical simulation equipment is not designed for in situ neutron scattering, which limits its application to in situ materials research by using neutrons. Here we present a resistive heating gas enclosure loadframe (RHEGAL) for non-equilibrium phase transformation studies by using in situ neutron scattering, which takes the advantage of high flux neutron sources like SNS. RHEGAL enables fast resistive heating of metal samples to 1200 °C at a rate up to 60 °C/s in an inert atmosphere. It provides both horizontal and vertical positions for scattering optimization. The mechanical loading capability also allows in situ high temperature tension above the oxidation temperature limit. The optimized translucent neutron scattering window by silicon allows both reflection and transmission measurements, making this equipment applicable for neutron diffraction, small angle scattering, and imaging. To demonstrate the fast heating capability, the phase transformations of an example of advanced high strength steel heated at 3 °C/s and 30 °C/s were measured with the VULCAN engineering diffractometer, and the different phase transformation kinetics by neutron diffraction were presented.

16.
Epidemiol Infect ; 144(14): 3091-3100, 2016 10.
Article in English | MEDLINE | ID: mdl-27457660

ABSTRACT

Dengue is the world's most prevalent mosquito-borne disease, with more than 200 million people each year becoming infected. We used a mechanistic virus transmission model to determine whether climate warming would change dengue transmission in Australia. Using two climate models each with two carbon emission scenarios, we calculated future dengue epidemic potential for the period 2046-2064. Using the ECHAM5 model, decreased dengue transmission was predicted under the A2 carbon emission scenario, whereas some increases are likely under the B1 scenario. Dengue epidemic potential may decrease under climate warming due to mosquito breeding sites becoming drier and mosquito survivorship declining. These results contradict most previous studies that use correlative models to show increased dengue transmission under climate warming. Dengue epidemiology is determined by a complex interplay between climatic, human host, and pathogen factors. It is therefore naive to assume a simple relationship between climate and incidence, and incorrect to state that climate warming will uniformly increase dengue transmission, although in general the health impacts of climate change will be negative.


Subject(s)
Climate Change , Dengue Virus/physiology , Dengue/epidemiology , Australia/epidemiology , Climate , Dengue/virology , Humans , Incidence , Models, Theoretical
17.
Epidemiol Infect ; 143(13): 2856-64, 2015 Oct.
Article in English | MEDLINE | ID: mdl-25591942

ABSTRACT

We aimed to reparameterize and validate an existing dengue model, comprising an entomological component (CIMSiM) and a disease component (DENSiM) for application in Malaysia. With the model we aimed to measure the effect of importation rate on dengue incidence, and to determine the potential impact of moderate climate change (a 1 °C temperature increase) on dengue activity. Dengue models (comprising CIMSiM and DENSiM) were reparameterized for a simulated Malaysian village of 10 000 people, and validated against monthly dengue case data from the district of Petaling Jaya in the state of Selangor. Simulations were also performed for 2008-2012 for variable virus importation rates (ranging from 1 to 25 per week) and dengue incidence determined. Dengue incidence in the period 2010-2012 was modelled, twice, with observed daily weather and with a 1 °C increase, the latter to simulate moderate climate change. Strong concordance between simulated and observed monthly dengue cases was observed (up to r = 0·72). There was a linear relationship between importation and incidence. However, a doubling of dengue importation did not equate to a doubling of dengue activity. The largest individual dengue outbreak was observed with the lowest dengue importation rate. Moderate climate change resulted in an overall decrease in dengue activity over a 3-year period, linked to high human seroprevalence early on in the simulation. Our results suggest that moderate reductions in importation with control programmes may not reduce the frequency of large outbreaks. Moderate increases in temperature do not necessarily lead to greater dengue incidence.


Subject(s)
Aedes , Climate Change , Dengue/epidemiology , Dengue/transmission , Entomology/methods , Models, Theoretical , Animals , Humans , Malaysia/epidemiology , Software
18.
Trop Med Int Health ; 20(5): 643-649, 2015 May.
Article in English | MEDLINE | ID: mdl-25630576

ABSTRACT

OBJECTIVES: To determine the association between diabetes and the clinical features and treatment outcomes of TB in Kiribati. METHODS: We enrolled consecutive patients with TB who presented from August 2010 to February 2012 and compared clinical features and TB treatment outcomes for patients with and without diabetes, as measured by haemoglobin A1c assay. Poor outcome was defined as death, default or treatment failure, and good outcome as treatment success or cure. RESULTS: Two hundred and seventy-five eligible persons with TB disease were enrolled; 101 (37%) had diabetes. TB patients with diabetes were more likely to have acid-fast bacilli (AFB) seen on sputum smear microscopy (RR: 1.3; 95% CI: 1.03-1.62). The risk of poor outcome did not differ between patients with or without diabetes (RR: 1.1; 95% CI: 0.5-2.7). CONCLUSION: TB patients with diabetes are more likely than those without to have sputum with AFB on microscopy. This could increase transmission in the community. Early detection of TB by screening patients with diabetes, and the converse, could be important public health interventions where diabetes and TB are prevalent.

19.
Trop Med Int Health ; 20(5): 650-657, 2015 May.
Article in English | MEDLINE | ID: mdl-25598275

ABSTRACT

OBJECTIVES: To better inform local management of TB-diabetes collaborative activities, we aimed to determine the prevalence of diabetes among persons with and without TB and to determine the association between TB and diabetes in Kiribati, a Pacific Island nation. METHODS: We compared consecutively enrolled TB cases to a group of randomly selected community controls without evidence of TB. Diabetes was diagnosed by HbA1c, and clinical and demographic data were collected. A tuberculin skin test was administered to controls. The chi-square test was used to assess significance in differences between cases and controls. We also calculated an odds ratio, with 95% confidence intervals, for the odds of diabetes among cases relative to controls. Unweighted multivariate logistic regression was performed to adjust for the effects of age and sex. RESULTS: A total of 275 TB cases and 499 controls were enrolled. The diabetes prevalence in cases (101, 37%) was significantly greater than in controls (94, 19%) (adjusted odds ratio: 2.8; 95% CI 2.0-4.1). Fifty-five percent (108) of all diabetic diagnoses were new; this proportion was higher among controls (64.8%) than cases (46.5%). Five patients with TB were screened to detect one patient with diabetes. CONCLUSIONS: There is a strong association between TB and diabetes in Kiribati and bidirectional screening should be conducted in this setting.

20.
Sci Rep ; 2: 747, 2012.
Article in English | MEDLINE | ID: mdl-23087812

ABSTRACT

We report an in-situ neutron diffraction study of a large format pouch battery cell. The succession of Li-Graphite intercalation phases was fully captured under an 1C charge-discharge condition (i.e., charge to full capacity in 1 hour). However, the lithiation and dilithiation pathways are distinctively different and, unlike in slowing charging experiments with which the Li-Graphite phase diagram was established, no LiC24 phase was found during charge at 1C rate. Approximately 75 mol. % of the graphite converts to LiC6 at full charge, and a lattice dilation as large as 4% was observed during a charge-discharge cycle. Our work demonstrates the potential of in-situ, time and spatially resolved neutron diffraction study of the dynamic chemical and structural changes in "real-world" batteries under realistic cycling conditions, which should provide microscopic insights on degradation and the important role of diffusion kinetics in energy storage materials.


Subject(s)
Electric Power Supplies , Lithium/chemistry , Electrodes , Graphite/chemistry , Ions/chemistry , Neutron Diffraction
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