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The Australian pork industry recognises that antimicrobial resistance (AMR) is a global threat to animal, human and environmental health. As early as the 1960s, caesarean-derived pigs were used to populate high health status farms. Depopulation of the herd and repopulation with high health status pigs enables producers to produce pigs without the need for antimicrobial protection against pleuropneumonia. Different management systems have replaced traditional systems to better manage pig flow, reduce disease transmission between and within pig batches and consequently reduce antimicrobial use. [Extracted from the article]

Hafnium carbide/tungsten ( HfC/ W) cermets were prepared by an in situ reaction sintering process, using hafnium oxide ( HfO2) and tungsten carbide ( WC) as the raw materials. The reaction path, densification behavior, microstructure development, and mechanical properties of the cermets were comprehensively investigated. It was found that WC decomposed to tungsten semicarbide ( W2 C) and tungsten ( W) in sequence, and meanwhile HfC was formed by carbothermal reduction between HfO2 and as-released carbon from the dissociation of WC. The solid solution formation between HfC and W during sintering was also studied. The obtained cermets (>98% TD) have a Vickers' hardness of 8.16 GPa, a fracture toughness of 14.45 MPa m1/2, and a high flexural strength of 1211 MPa. [ABSTRACT FROM AUTHOR]

Composites consisting of 70 vol% ZrB2 and 30 vol% α- SiC particles were hot pressed to near full density and subsequently annealed at temperatures ranging from 1000°C to 2000°C. Strength, elastic modulus, and hardness were measured for as-processed and annealed composites. Raman spectroscopy was employed to measure the thermal residual stresses within the silicon carbide ( SiC) phase of the composites. Elastic modulus and hardness were unaffected by annealing conditions. Strength was not affected by annealing at 1400°C or above; however, strength increased for samples annealed below 1400°C. Annealing under uniaxial pressure was found to be more effective than annealing without applied pressure. The average strength of materials annealed at 1400°C or above was ~700 MPa, whereas that of materials annealed at 1000°C, under a 100 MPa applied pressure, averaged ~910 MPa. Raman stress measurements revealed that the distribution of stresses in the composites was altered for samples annealed below 1400°C resulting in increased strength. [ABSTRACT FROM AUTHOR]

Direct synthesis of silicon carbide ( SiC) nanopowders (size 50-200 nm, BET ~20 m2/g) in Si- C system is conducted in an inert atmosphere (argon) using a self-propagating high-temperature synthesis ( SHS) approach. A preliminary short-term (e.g., minutes) high-energy ball milling ( HEBM) of the initial mixture, which involves pure Si and C powders, is used to enhance system reactivity. Two conditions of HEBM with different force fields (17G and 90G) are applied and the results are compared. The influence of HEBM's conditions on the microstructure of mechanically treated mixtures and combustion products is also investigated and discussed. Obtained results suggest that by changing the intensity of mechanical treatment one may prepare a completely amorphous reactive mixture containing carbon and silicon, or gradually change the ratio of ( Si/ C)- SiC phases and finally produce pure silicon carbide powder during the milling process. The influence of HEBM on the combustibility of the Si/ C mixture possesses a critical character: the self-sustained reaction becomes feasible only after a critical time of ball milling (i.e., 10 min for 90G; 30 min for 17G). Comparison of the microstructures for as-milled and as-synthesized powders reveals that for all investigated conditions the morphologies of the as-milled reactive Si/ C media are essentially the same as that for SiC combustion products. The mechanism for direct synthesis of SiC by combustion reaction is also proposed. [ABSTRACT FROM AUTHOR]

The fabrication of dense submicrometer grained B4 C- TiB2 composite (molar ratio equal to 1:1) is investigated in this work through the combination of mechanical (Ball Milling) and electric current (spark plasma sintering or SPS) activation of Ti, B, and graphite reactants. The full conversion of 8 h milled powders is obtained at much lower temperature (about 1200°C), as compared with simply blended reactants (>1600°C). The formation of TiB2 generally precedes that of B4 C. In addition, regardless of the milling treatment, an increase in the heating rate during SPS is found to produce a transition of the mechanism governing the formation of TiB2 and B4 C, from gradual solid-solid to rapid combustion-type behavior. Nevertheless, when unmilled powders are used, not negligible amounts of unreacted and intermediate species are still present in the product resulting after the combustion synthesis event. In contrast, ball milled powders reacted completely under combustion regime, even when relatively milder heating rate conditions are adopted. As a consequence of the mechanical treatment, SPS product density increases from about 82% to 94% of the theoretical value ( I = 1100 A). Correspondingly, a material with homogeneous phase distribution and grain size down to 100-200 nm is obtained. In this regard, when a combustion synthesis regime is established, a slight coarsening in product microstructure (1-2 μm) is observed. A further improvement of product density (higher than 96.5%) is obtained, at the expenses of a certain grain growth, when the applied current intensity is augmented to 1200 A. [ABSTRACT FROM AUTHOR]

The synthesis of multicomponent ceramic materials in the titanium-diboride-carbide-nitride-carbonitride system by the mechanochemical process known as the mechanically induced self-sustaining reaction ( MSR) was investigated. Ceramic composite powders containing TiB2 and TiC, TiN or TiC x N1− x were prepared from a blended mixture of the elements by exploiting the highly exothermic nature of the formation reactions. The synthesis of the composite materials was made possible by the ability of the MSR to simultaneously induce independent self-sustaining reactions, generating a mixture of ceramic phases. The composition of the ceramic composites was designed using the initial atomic ratio of the reactants, and the achieved microstructure was characterized by TiB2 particles in the micrometric range, surrounded by submicrometric and nanometric TiC, TiN, or TiC x N1− x crystals. [ABSTRACT FROM AUTHOR]

The gelling process in the aqueous lanthanum-cobalt-citric acid system was studied using UV-VIS and IR spectroscopic methods, as well as viscosity measurements, to establish the gelling mechanism of transition metal ions ( La3+ and Co2+) in the presence of chelating agent. Lanthanum and cobalt nitrates and lanthanum and cobalt acetates, respectively, were used as starting reagents, and the citric acid was used as chelating agent. The gelation process was investigated at room temperature and at 80°C. At elevated temperature, the gels were obtained after 30 h, whereas at room temperature, these were obtained in 1 month. Complex gels were formed for the both studied systems. The Co2+ ions mainly present an octahedral symmetry during the whole gelation process, whereas the citric acid acts as monodentate or bridging ligand depending on the metal precursors used. The mechanism of formation of the La-Co-CA based gels with the coordinative structures was proposed. [ABSTRACT FROM AUTHOR]

Flexural strength, elastic modulus, and hardness were used to characterize the mechanical properties of ZrB2-SiC composites that contained varying SiC particle sizes. Dense ZrB2-SiC composites consisting of 70 vol% ZrB2 and 30 vol% α-SiC were produced via hot pressing. This series of composites had maximum SiC particle sizes that ranged from 4.4 to 18 μm. The mechanical properties scaled with the maximum SiC particle size, not with ZrB2 grain size. Flexural strength decreased as the maximum size of SiC particles increased from 1150 MPa at 4.4 μm to 245 MPa at 18 μm with an abrupt decrease in strength at ~11.5 μm. Elastic modulus remained constant at ~530 GPa for compositions containing SiC particles smaller than 11.5 μm, but exhibited a decrease with larger SiC particle sizes. Vickers and Knoop hardness were 21.4 and 17.2 GPa, respectively, for ceramics with SiC particle sizes <11.5 μm, but hardness decreased for larger SiC particle sizes. The decreases in strength, elastic modulus, and hardness with SiC particles larger than 11.5 μm were coincident with stress-induced microcracking in the composites. [ABSTRACT FROM AUTHOR]

Green body formation with nanoscale powders poses unique challenges. This report discusses two specific green-forming procedures: pressure filtration and dry-powder compaction. Green compacts were formed from suspensions of hydrothermally derived YTZP prepared in the presence of bicine, which acts as a protective colloid and dispersant. However, due to capillary forces encountered when drying filter-pressed, nanoporous compacts, green bodies could not be recovered intact. Dry-powder compaction is explored as an alternative green-forming technique. The effect of powder recovery procedure on compaction behavior and microstructural homogeneity are discussed. Strong capillary forces also act on nanoparticles during pan-drying, yielding high-strength aggregates which are difficult to deform during compaction. Drying particles from a lower surface tension liquid, such as ethanol, is found to have little effect on aggregate strength. Freeze-drying is demonstrated as the preferred powder recovery technique since particles are kept in a dispersed state during drying, and compression of agglomerates by capillary forces is avoided. Compaction behavior of recovered powders is examined with a model that describes powder consolidation as an activated process. From this analysis, it is demonstrated that granule deformation and rearrangement contribute equally to the compaction process in pan-dried nanopowders. It is also shown that primary particle rearrangement accounts for the majority of compaction in freeze-dried nanopowders. [ABSTRACT FROM AUTHOR]

Ceramic composite rods of alumina filled with varying volume fractions of silicon carbide whiskers ( SiCw) were made by extrusion and pressureless-sintering. The electrical response was measured over a wide range of frequency (1 mHz-1.8 GHz) and was compared to that of disks made by dry-pressing and pressureless-sintering the same starting powder blends. Extrusion resulted in increased whisker alignment and electrical conductivity along the processing direction compared to dry-pressing. Pressureless sintering resulted in anisotropic shrinkage and the rods having lower density ( D), dc conductivity (σdc), and SiCw-SiCw connection quality compared to fully dense hot-pressed disks. Porosity ( P = 1 − D) increased with SiCw loading and was linearly related to the rod elastic modulus, which was determined via sonic resonance. SiCw percolation in the extruded rods required greater SiCw loading, took place over a wider compositional range, and resulted in significantly decreased σdc for the rods compared to hot-pressed disks. The σdc of percolated rods having composition near the percolation threshold was sensitive to small changes in porosity and was correlated to the elastic modulus. The weak percolation transition was correlated to a gradual evolution of the complex permittivity spectra. As SiCw content was increased, such spectra exhibited dc-conductivity tails in the loss which grew in magnitude, and dielectric relaxations which grew in strength, shifted to lower frequency, spread out over wider frequency ranges, and seemed to evolve toward power-law behavior for the dielectric constant. [ABSTRACT FROM AUTHOR]

The tribological behavior of 5 wt% copper oxide-doped tetragonal zirconia polycrystal composite has been investigated while it slides against an alumina counterface under high temperature conditions. The effects of load (1, 2.5, and 5 N) and velocity (0.05 and 0.1 m/s) on the wear mechanism have been investigated. The results were compared with undoped zirconia at 595°C. A coefficient of friction ( COF) of 0.35 and a specific wear rate less than 10−6 mm3/Nm were obtained at 595°C when copper oxide was added to zirconia. Further, it has been observed that a self-lubricating layer is formed at the interface. Scanning electron microscopy and X-ray photoelectron spectroscopy have been used to investigate the formation of the self-lubricating copper-rich layer at the interface between the disk and counterface materials. The formation of a self-lubricating layer, as well as the wear mechanisms at different operational conditions (load and velocity) are discussed. It appears that plastic deformation of copper-rich phase at higher temperature is responsible for the decrease in friction and wear. [ABSTRACT FROM AUTHOR]

A new synthesis method of using dehydration of sugar (sucrose) with concentrated sulfuric acid was developed to synthesize mixed oxide ceramic particles with flaky shape. The anode disks prepared from flake-shaped NiO- YSZ particles without a pore-forming additive exhibited uniform dispersion of NiO and YSZ and a high porosity (45.6%), leading to improved cell performance as compared with an anode prepared from conventional NiO- YSZ powder in Ni- YSZ/YSZ/LSM single cells operated with H2 as the fuel; their maximum power densities were 381 and 300 mW·cm−2 at 850°C, respectively. [ABSTRACT FROM AUTHOR]

In this paper, we characterize a temperature dependence in longan ( Dimocarpus longan Lour.) cultivars using the high annealing temperature random-amplified polymorphic DNA (HAT-RAPD) methodology. This form of genomic analysis allows a random sampling of the complete genome to provide information about phenotypic traits of interest. Using a set of 18 unique decamer primers, polymorphic bands ranging from 100 to 2500 bp were examined for 14 longan varieties from which banding patterns of interest were selected for conversion to the more reproducible and robust sequence characterized amplified region (SCAR) markers. In particular, one SCAR marker produced an electrophoresis banding pattern which could distinguish between longan varieties requiring a sustained interval at low temperatures for fruit production vs. those that do not. This band was composed of a nucleotide region 275 bases in length (DQ539047) in which the initial 90 nucleotides were >85 % identical to the 12-oxophytodienoic acid (OPDA) reductase gene. OPDA is an immediate precursor to jasmonic acid which has been described as the ‘master switch’ for lipid-derived environmental signalling to factors such as flowering and osmotic stress. The possible involvement of the jamonic acid signalling pathway could explain the recent success of potassium chlorate to induce off-season flowering and fruit formation. [ABSTRACT FROM AUTHOR]

R-curve behavior of Si3N4-BN composites and monolithic Si3N4 for comparison was investigated. Si3N4-BN composites showed a slowly rising R-curve behavior in contrast with a steep R-curve of monolithic Si3N4. BN platelets in the composites seem to decrease the crack bridging effects of rod-shaped Si3N4 grains for small cracks, but enhanced the toughness for long cracks as they increased the crack bridging scale. Therefore, fracture toughness of the composites was relatively low for the small cracks, but it increased significantly to ∼8 MPa·m½ when the crack grew longer than 700 μm, becoming even higher than that of the monolithic Si3N4. [ABSTRACT FROM AUTHOR]

Investigates the correlation of the lattice oxygen content and thermal conductivity of the fabricated beta-silicon nitride with additives. Determination of the oxygen content using hot-gas extraction and electron spin resonance; Relationship of the microstructure, grain-boundary phase, lattice oxygen content and thermal conductivity of the sintered bodies.

Colestipol and gemfibrozil may be used in combination to lower serum cholesterol and triglycerides. Since colestipol is known to bind certain anionic drugs, we studied the effect of colestipol on the pharmacokinetics of gemfibrozil in 10 patients with elevated serum cholesterol and triglycerides. Each patient received 600 mg of gemfibrozil by mouth during four different studies. Gemfibrozil was given randomly either alone, with, 2 hours before, or 2 hours after 5 grams of colestipol. The serum gemfibrozil concentration time curves were similar when gemfibrozil was given alone or two hours before or after colestipol. There was also no statistical difference in peak gemfibrozil concentration (Cmax), time to Cmax (tmax), area under the curve (AUC), or serum elimination half-life (t1/2) between any of these three treatments. However, when colestipol was given with gemfibrozil, there was a decrease in AUC (43.6 ± 21.9 mg*hr/L) compared with gemfibrozil given alone (62.6 ± 10.3 mg*hr/L) which was statistically different by both ANOVA and paired t-test. This finding suggests a decrease in gemfibrozil bioavailability. Cmax when colestipol was given with gemfibrozil (14.7 ± 6.6 mg/L) was not statistically different from gemfibrozil alone (20.1 ± 4.9 mg/L). However, the mean serum concentrations when gemfibrozil was given with colestipol were significantly lower at the 0.5, 1.0 and 1.5 hour sampling times when compared to the other regimens. Gemfibrozil serum elimination half-life was not significantly altered by combination with colestipol. The data suggest a reduction of gemfibrozil bioavailability when colestipol is administered concomitantly. Separating the administration of these two drugs by at least two hours will avoid this drug interaction. [ABSTRACT FROM AUTHOR]

The article comments on the value of science-based welfare assessment in animal farming. Researchers argue that it should encompass moral and ethical considerations as shown of sows' confinement in stalls. According to the authors, it is only consumers who can encourage the pig industry to invest in the construction of new housing for sows that is financially sustainable for the farmer. They emphasize the role of the government in facilitating demand for certified range-bred products.

The role of the gastrointestinal microbiome in predisposing to chronic graft-versus-host disease (cGVHD), an immune-mediated haematopoietic cell transplant (HCT) complication, is not well defined. We examined the relationship of the host faecal microbiome with subsequent cGVHD development by analysing baseline stool samples as well as post-HCT changes in microbiome composition and metabolite pathway analyses. We analysed pre-transplant baseline samples from 11 patients who subsequently developed cGVHD compared to 13 controls who did not develop acute GVHD or cGVHD at any time. We found a significant differential abundance of multiple taxa at baseline between cGVHD versus controls, including the Actinobacteria phylum and Clostridium genus. A subgroup analysis of longitudinal samples within each patient revealed a greater loss of alpha diversity from baseline to post-engraftment in patients who subsequently developed cGVHD. Metabolic pathways analysis revealed that two pathways associated with short-chain fatty acid metabolism were enriched in cGVHD patient microbiomes: β-oxidation and acyl-CoA synthesis, and γ-aminobutyrate shunt. In contrast, a tryptophan catabolism pathway was enriched in controls. Our findings show a distinct pattern of baseline microbiome and metabolic capacity that may play a role in modulating alloreactivity in patients developing cGVHD. These findings support the therapeutic potential of microbiome manipulation for cGVHD prevention., (© 2023 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

To examine the renal effects of ibopamine HCl we evaluated 15 patients with New York Heart Association Class II-III congestive heart failure and mild renal insufficiency (creatinine clearance [CLcr] = 45-85 ml min-1). Diuretics and vasodilators were withheld and a sodium (Na+)-restricted diet was initiated. All patients exhibited positive Na+ balance at the time of evaluation. Hourly urine volumes, urine chemistries, serum chemistries, PAH and inulin/iothalamate clearances were determined 2 h pre and 4 h post a single 200 mg oral dose of ibopamine. Effective renal plasma flow, creatinine clearance, filtration fraction, and the fractional excretion of sodium and potassium were not significantly altered postdose. A significant increase in urine output and decrease in urine osmolality were seen at all time points postdose. A significant reduction in serum potassium (2 and 3 h) and blood urea nitrogen (1, 3 and 4 h) concentrations occurred. Measurements of glomerular filtration rate by inulin or [125I]-iothalamate produced differing results in the patient groups studied. We conclude that a single dose of ibopamine does not produce significant improvements in renal function in patients with congestive heart failure, mild renal insufficiency and positive sodium balance.