Mechanical Dispersion of a Semi-Solid Binder in a Wet Granulation Process

High viscosity surfactant pastes have recently gained popularity in the production of high efficiency laundry detergents due to their ability to increase surfactant loading in granules. When using high viscosity semi-solid binders a unique challenge is presented because it forces granules to be formed primarily by mechanical dispersion; a relatively poorly understood process. Developing mechanistic models of this process will enhance knowledge of mechanical dispersion processes and improve process development for granules produced using this method. Experiments to determine the effect of three process parameters; paste temperature, impeller RPM, and time were carried out in a lab-scale granulator. Binder temperature was varied between 40-60 degrees Celsius to cover paste temperatures from solidification to decomposition. Impeller RPM was varied between 600 -1200 RPM to capture the full range of potential industrial impeller velocities. Mixing time was varied from zero to ten seconds; the time scale of the industrial process. The particle size distribution for the process was determined to rely primarily on mixing time especially at impeller speeds above 900 RPM where fully developed annular flow occurs in the mixer. The Sauter mean diameter of particles was determined to be linearly related to mixing RPM, while temperature was shown to have little effect on the Sauter mean diameter. Experimental data was in relatively good agreement with values predicted by an existing breakage simulation, but could be improved upon. These conclusions will be used in developing a breakage kernel for the process based on material properties

Simple fence modification increases land movement prospects for freshwater turtles on floodplains

Installing conservation fences to prohibit feral animal access to wetlands can become a barrier for non-target species of interest. We collected 161 turtles (Chelodina rugosa, Emydura subglobosa worrelli, Myuchelys latisternum) from twenty floodplain and riverine wetlands during post-wet (June–August) and late-dry season (November–December) surveys (2015–2018) in northern Australia. Wetlands were fenced (150 × 150 mm square, 1.05 m high wire mesh) or unfenced around the wet perimeter. Ninety-seven percent of individuals caught in either fenced or unfenced wetlands had a shell carapace width greater than mesh width, of these 44 (46%) were captured inside fenced wetlands, while 50 were caught in unfenced wetlands. The remaining 35 turtles were smaller than 150 mm and would likely pass easily through fence mesh. Sixty-five turtles partook in a fencing manipulative experiment. Turtles with carapace widths wider than mesh often successfully escaped through fences by lifting one side of their shell and passing diagonally through the mesh. In a second experiment where a piece of vertical wire (1500 × 300 mm) was removed, turtles located ‘gates' after prospecting and fitting through meshing areas that were too small to pass. Ninety-two percent of turtles were able to locate and pass through gates, while 8% failed to locate a gate after 2 h. Gates applied every 4 m showed an 83% passage rate, every 2 m was 91%, and every 1 m was 100%. Combing field and manipulative experiments revealed that large turtles will prospect and move along a fence until they find suitable passage, which has important consequences when considering that gates could be easily retrofitted to existing sites, as well in new fencing programs, which has enormous positive conservation benefits for turtles in an already challenging and changing floodplain environment

Enzyme-catalysed polymer cross-linking:Biocatalytic tools for chemical biology, materials science and beyond

Intermolecular cross-linking is one of the most important techniques that can be used to fundamentally alter the material properties of a polymer. The introduction of covalent bonds between individual polymer chains creates 3D macromolecular assemblies with enhanced mechanical properties and greater chemical or thermal tolerances. In contrast to many chemical cross-linking reactions, which are the basis of thermoset plastics, enzyme catalysed processes offer a complimentary paradigm for the assembly of cross-linked polymer networks through their predictability and high levels of control. Additionally, enzyme catalysed reactions offer an inherently ‘greener’ and more biocompatible approach to covalent bond formation, which could include the use of aqueous solvents, ambient temperatures, and heavy metal-free reagents. Here, we review recent progress in the development of biocatalytic methods for polymer cross-linking, with a specific focus on the most promising candidate enzyme classes and their underlying catalytic mechanisms. We also provide exemplars of the use of enzyme catalysed cross-linking reactions in industrially relevant applications, noting the limitations of these approaches and outlining strategies to mitigate reported deficiencies

Regional seasonality of fire size and fire weather conditions across Australia's northern savanna

Australia's northern savannas have among the highest fire frequencies in the world. The climate is monsoonal, with a long, dry season of up to 9 months, during which most fires occur. The Australian Government's Emissions Reduction Fund allows land managers to generate carbon credits by abating the direct emissions of CO2 equivalent gases via prescribed burning that shifts the fire regime from predominantly large, high-intensity late dry season fires to a more benign, early dry season fire regime. However, the Australian savannas are vast and there is significant variation in weather conditions and seasonality, which is likely to result in spatial and temporal variations in the commencement and length of late dry season conditions. Here, we assess the temporal and spatial consistency of the commencement of late dry season conditions, defined as those months that maximise fire size and where the most extreme fire weather conditions exist. The results demonstrate that significant yearly, seasonal and spatial variations in fire size and fire weather conditions exist, both within and between bioregions. The effective start of late dry season conditions, as defined by those months that maximise fire size and where the most extreme fire weather variables exist, is variable across the savannas

Capturing Fleeting Intermediates in a Catalytic C-H Amination Reaction Cycle

We have applied an ambient ionization technique, desorption electrospray ionization MS, to identify transient reactive species of an archetypal C–H amination reaction catalyzed by a dirhodium tetracarboxylate complex. Using this analytical method, we have detected previously proposed short-lived reaction intermediates, including two nitrenoid complexes that differ in oxidation state. Our findings suggest that an Rh-nitrene oxidant can react with hydrocarbon substrates through a hydrogen atom abstraction pathway and raise the intriguing possibility that two catalytic C–H amination pathways may be operative in a typical bulk solution reaction. As highlighted by these results, desorption electrospray ionization MS should have broad applicability for the mechanistic study of catalytic processes

Presentation and Outcomes After Medical and Surgical Treatment Versus Medical Treatment Alone of Spontaneous Infectious Spondylodiscitis: A Systematic Literature Review and Meta-Analysis.

Study Design: Systematic literature review. Objectives: The aims of this study were to (1) describe the clinical features, disabilities, and incidence of neurologic deficits of pyogenic spondylodiscitis prior to treatment and (2) compare the functional outcomes between patients who underwent medical treatment alone or in combination with surgery for pyogenic spondylodiscitis. Methods: A systematic literature review was performed using PubMed according to PRISMA guidelines. No year restriction was put in place. Statistical analysis of pooled data, when documented in the original report (ie, number of patients with desired variable and number of patients evaluated), was conducted to determine the most common presenting symptoms, incidence of pre- and postoperative neurologic deficits, associated comorbidities, infectious pathogens, approach for surgery when performed, and duration of hospitalization. Outcomes data, including return to work status, resolution of back pain, and functional recovery were also pooled among all studies and surgery-specific studies alone. Meta-analysis of studies with subgroup analysis of pain-free outcome in surgical and medical patients was performed. Results: Fifty of 1286 studies were included, comprising 4173 patients undergoing either medical treatment alone or in combination with surgery. Back pain was the most common presenting symptom, reported in 91% of patients. Neurologic deficit was noted in 31% of patients. Conclusion: Medical management remains first-line treatment of infectious pyogenic spondylodiscitis. Surgery may be indicated for progressive pain, persistent infection on imaging, deformity or neurologic deficits. If surgery is required, reported literature shows potential for significant pain reduction, improved neurologic function and a high number of patients returning to a normal functional/work status

An evaluation of nest predator impacts and the efficacy of plastic meshing on marine turtle nests on the western Cape York Peninsula, Australia

Nest predation is considered to be one of the most significant biotic threats to marine turtle populations globally. The introduction of feral predators to nesting beaches has dramatically increased nest predation, reaching near total egg loss in some regions. We monitored a 48 km stretch of beach along western Cape York Peninsula, Australia, from June – November 2018. We recorded a total of 360 nests comprising 117 flatback and 243 olive ridley nests. We installed plastic meshing (90 cm × 100 cm) on 110 olive ridley nests (45.2% of total olive ridley clutches laid) within the study area. We classified all nest predation attempts into three categories: complete, partial, or failed predation events. In total, 109 (30.2%) of all marine turtle nests were depredated by a variety of predators, including feral pigs, dingoes, goannas, and humans. The addition of plastic meshing reduced the likelihood of dingoes gaining access to eggs, but not goannas or feral pigs. Further, we found no difference in the proportion of hatchling emergence between meshed and un-meshed nests. Additionally, while hatchling emergence was reduced in nests that had been partially depredated, these nests still produced live hatchlings and contributed to recruitment. The success of particular predator control methods is often predator, and/or regionally, specific. Our findings highlight a thorough understanding of predator guilds and their relative impacts is required to deploy targeted and predator-specific strategies to maximize conservation results. We present a strong case for data-driven adaptive management that has implications for designing optimal predator management plans

Sterol 3β-glucosyltransferase biocatalysts with a range of selectivities, including selectivity for testosterone

The main objectives of this work were to characterise a range of purified recombinant sterol 3β-glucosyltransferases and show that rational sampling of the diversity that exists within sterol 3β-glucosyltransferase sequence space can result in a range of enzyme selectivities. In our study the catalytically active domain of the Saccharomyces cerevisiae 3β-glucosyltransferase was used to mine putative sterol 3β-glucosyltransferases from the databases. Selected diverse sequences were expressed in and purified from Escherichia coli and shown to have different selectivities for the 3β-hydroxysteroids ergosterol and cholesterol. Surprisingly, three enzymes were also selective for testosterone, a 17β-hydroxysteroid. This study therefore reports for the first time sterol 3β-glucosyltransferases with selectivity for both 3β- and 17β-hydroxysteroids and is also the first report of recombinant 3β-glucosyltransferases with selectivity for steroids with a hydroxyl group at positions other than C-3. These enzymes could therefore find utility in the pharmaceutical industry for the green synthesis of a range of glycosylated compounds of medicinal interest

Assembly of 809 whole mitochondrial genomes with clinical, imaging, and fluid biomarker phenotyping

INTRODUCTION: Mitochondrial genetics are an important but largely neglected area of research in Alzheimer's disease. A major impediment is the lack of data sets. METHODS: We used an innovative, rigorous approach, combining several existing tools with our own, to accurately assemble and call variants in 809 whole mitochondrial genomes. RESULTS: To help address this impediment, we prepared a data set that consists of 809 complete and annotated mitochondrial genomes with samples from the Alzheimer's Disease Neuroimaging Initiative. These whole mitochondrial genomes include rich phenotyping, such as clinical, fluid biomarker, and imaging data, all of which is available through the Alzheimer's Disease Neuroimaging Initiative website. Genomes are cleaned, annotated, and prepared for analysis. DISCUSSION: These data provide an important resource for investigating the impact of mitochondrial genetic variation on risk for Alzheimer's disease and other phenotypes that have been measured in the Alzheimer's Disease Neuroimaging Initiative samples