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• An open-source Modelica-based methodology for PCHE modelling is shared, called SCOPE. • The proposed 1D PCHE model is tested against both literature and experiments. • The SCOPE is feasible under steady, part-load and transient scenarios. As the most widely-used heaters and recuperators in supercritical CO 2 (sCO 2) power cycles, the Printed Circuit Heat Exchangers (PCHEs) have received considerable interest to investigate their steady, off-design and transient behaviour mainly by simulations, which remains a challenging task accounting for various application scenarios. After an introduction and comparison about the state-of-art PCHEs numerical approaches, this paper presents a generic one-dimensional (1D) numerical PCHE modelling methodology featured by (1) ability fulfilling the steady, off-design and transient simulation; (2) precise capture of the non-linear local variations in the thermo-physical properties of sCO 2 ; (3) feasibility for a wide range of flow patterns, working fluids, and operation conditions. The off-design prediction via the proposed 1D PCHE modelling methodology is justified by validating its Modelica implementation against previous literature. Later, one optimal Nusselt correlation out of five candidates is identified to reproduce two typical transient power cycle operations, i.e., 'shutdown and startup' and 'ramp-up' scenario. These scenarios are validated by experiments at the Pinjarra Hills High Pressure Loop (PHPL) of the University of Queensland. The proposed 1D PCHE model successfully follows the changing rules of the time-varying temperature of both hot- and cold-side working fluids, though a slight time lag is observed between the simulation and experiment, which is caused by the modelling assumptions. In general, the presented 1D PCHE modelling methodology is credited for the steady, part-load and transient performance evaluation of sCO 2 power blocks and the corresponding control strategy development. Several crucial future work is summarized for guidance. [ABSTRACT FROM AUTHOR]

Highlights: [•] Proposal for cooling condensers of geothermal plants in central Australia. [•] Suitable reserves of groundwater at <25°C are shown to be available. [•] For low-temperature geothermal brines the hot-weather plant performance is improved. [•] For high-temperature (>250°C) geothermal brines performance improvement is small. [ABSTRACT FROM AUTHOR]

Abstract: Group A streptococci (GAS) cause a number of human diseases ranging from pharyngitis to necrotizing fasciitis. GAS are hypothesized to escape killing by either the immune system or beta lactam antibiotics by internalization into epithelial cells. A Tn917 library of transposon mutants was screened for capacity to invade and survive in human epithelial cells using a novel blood agar overlay method. Although the screen revealed that a majority of Tn917 insertions occurred within a 10kb region of the genome, GAS genes identified as essential for internalization into epithelial cells included ABC transporters, and DNA maintenance proteins, and citrate metabolism enzymes, underlining the importance of adaptation to the intracellular environment. [Copyright &y& Elsevier]

Abstract: The superantigens, toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxin B (SEB), were recently reported to repress global exoprotein synthesis in Staphylococcus aureus. To investigate if this phenomenon could be observed in a different Gram-positive pathogen, the effects of two major Streptococcus pyogenes superantigens on streptococcal secretome expression were examined. Using mutagenesis and genetic complementation, we demonstrated that neither streptococcal pyrogenic exotoxin A (SPEA) nor streptococcal mitogenic exotoxin Z (SMEZ) had any consistent effect on global protein expression or on transcription of genes encoding the secreted exoproteins, DNase B, SPEB and SPEG. In S. pyogenes, superantigen production does not appear to have a major regulatory role. [Copyright &y& Elsevier]

In thermal power cycles including concentrating solar thermal (CST) plants, natural draft cooling towers (NDCTs) are widely used heat-dumping facilities. One inherent drawback of NDCTs is that their cooling performance can be compromised by changes in ambient conditions, particularly temperature, which inevitably reduces the net power output of the cycles. Current methods resolving this issue are limited in a few options including inlet air pre-cooling, exit air heating, and fan assistance, each with considerable operational or initial cost. To more economically reduce energy efficiency losses of the power cycles due to inefficient cooling, this paper proposes a new concept of swirling plume method for both dry- and wet-type NDCTs. The method is to rotate the plume strongly like a tornado in the tower upper part and above the towers to increase the overall tower updraft capacity (pressure). The swirling plume is induced by high-speed air jets distributed at certain locations using a much smaller flow rate. A numerical investigation on a 20 m-tall dry-type NDCT model has been conducted verifying that this concept increases the airflow and the water temperature drop of the heat exchanger by at least 53.6% and 3.57 °C (39.2%), respectively, under 35 °C ambient temperature. This cooling performance enhancement enables a half megawatt-scale sCO 2 -based CST power cycle to recover its net power output, by 4.98%, to the level almost same as that at 30 °C ambient temperature. The air jet to create such a swirling plume consumes only 1/7 of the recovered power roughly. Compared with a traditional fan-forced cooler working under exactly the same condition, this concept requires significantly smaller energy in long-term operations as it would run only during temperature extremes. A simplified analytical modelling has found that the cooling tower performance is improved due to that the swirling plume creates an equivalent extra draft height on top of the tower which is attributed to two different vortical effects. The overall angular momentum of the swirl is a critical factor in these effects. [ABSTRACT FROM AUTHOR]

Taylor–Couette–Poiseuille flow commonly occurs in rotating machinery in the annulus between the outer casing and rotating shaft as part of lubrication or thermal management systems. To improve efficiency of these machines, industry is beginning to work with low viscosity, high density fluids operating at high pressures, such as supercritical carbon dioxide turbines. Within existing literature, vast high quality heat transfer data exists for air under Taylor–Couette–Poiseuille flow regimes. However, for other fluids, these data are limited in their experimental coverage, especially at high Taylor numbers (i.e. > 1 × 10 10). This paper presents first of its kind experimental data for supercritical carbon dioxide. The data are analysed to provide insight into the heat transfer processes and to provide a Taylor–Couette–Poiseuille flow heat transfer correlation. Operating conditions of the experimental campaign cover pressures of 7 and 10 MPa, a temperature range of 315 to 333 K, and rotational speeds of 10 to 25 kRPM. This equates to Taylor number and axial Reynolds number ranges of 9.52 × 10 10 to 8.73 × 10 11 and 3.41 × 10 4 to 5.4 × 10 4 , respectively. The range of conditions tested covers the operational envelope of those found in thermal management systems for supercritical carbon dioxide turbine designs. It is found that heat transfer of supercritical carbon dioxide is significantly higher than that of ideal gases (e.g. air) for the same Taylor number range. Further findings show that change in fluid properties near the critical point (i.e. heat capacity and density) increase the Nusselt number from 1.5 × 10 3 at 10 MPa to 3.1 × 10 3 at 7 MPa at an effective Reynolds number of 2.5 × 10 6. A dimensional analysis shows the importance of capturing the change in fluid properties when near the critical point and to account for tangential energy transport. To capture this we introduce a non-dimensional parameter, Ψ , being the ratio of tangential energy flux to inertial energy flux. Including Ψ in heat transfer correlations improves their validity by capturing additional mechanisms that influence heat transfer. The suitability of correlations including Ψ are demonstrated using air and supercritical carbon dioxide data sets. Finally, analysing heat transfer trends across the range of Ψ tested provides insight on how heat transfer mechanisms vary with operating condition. This work provides a vital step forward for the unification of Taylor–Couette–Poiseuille flow heat transfer correlations across multiple experimental data sets. [ABSTRACT FROM AUTHOR]

Ground source heat pumps (GSHPs) are one of the most widespread forms of geothermal energy technology. They utilise the near-constant temperature of the ground below the frost line to achieve energy-efficiencies two or three times that of conventional air-conditioners, consequently allowing a significant offset in electricity demand for space heating and cooling. Relatively mature GSHP markets are established in Europe and North America. GSHP implementation in Australia, however, is limited, due to high capital price, uncertainties regarding optimum designs for the Australian climate, and limited consumer confidence in the technology. Existing GSHP design standards developed in the Northern Hemisphere are likely to lead to suboptimal performance in Australia where demand might be much more cooling-dominated. There is an urgent need to develop Australia's own GSHP system optimisation principles on top of the industry standards to provide confidence to bring the GSHP market out of its infancy. To assist in this, the Queensland Geothermal Energy Centre of Excellence (QGECE) has commissioned a fully instrumented GSHP experimental facility in Gatton, Australia, as a publically-accessible demonstration of the technology and a platform for systematic studies of GSHPs, including optimisation of design and operations. This paper presents a brief review on current GSHP use in Australia, the technical details of the Gatton GSHP facility, and an analysis on the observed cooling performance of this facility to date. [ABSTRACT FROM AUTHOR]

In this study, a nanoindentation-based microcantilever bending technique was utilized to investigate the interfacial properties of a β-Mg 17 Al 12 /AZ91 Mg alloy film/substrate system under tensile loading conditions. Finite element analysis (FEA) was first undertaken to optimise the design of cantilever structures for inducing high tensile stresses at the interface. Cantilevers consisting of a necked region or notch at the interface were determined to be the most successful designs. Microcantilevers containing the β-Mg 17 Al 12 /AZ91 interface were then made using focused ion beam (FIB) milling technique. Necks were made in the cantilevers to intensify the tension at the interface and notches were used to introduce a stress concentration to the interface. During bending, the cantilevers were deflected to failure. Subsequent analysis of the deformed cantilevers using electron microscopies revealed that plastic deformation, and subsequent ductile rupture, of the AZ91 phase was the dominant failure mechanism. When the β-Mg 17 Al 12 /AZ91 film/substrate system was subjected to tension, the softer AZ91 phase failed prior to interfacial delamination, demonstrating that the strength of the interface exceeded the stresses that caused ductile failure in the substrate material. [ABSTRACT FROM AUTHOR]

Automated planar patch clamp systems are widely used in drug evaluation studies because of their ability to provide accurate, reliable, and reproducible data in a high-throughput manner. Typically, CHO and HEK tumorigenic cell lines overexpressing single ion channels are used since they can be harvested as high-density, homogenous, single-cell suspensions. While human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) are physiologically more relevant, these cells are fragile, have complex culture requirements, are inherently heterogeneous, and are expensive to produce, which has restricted their use on automated patch clamp (APC) devices. Here, we used high efficiency differentiation protocols to produce cardiomyocytes from six different hPSC lines for analysis on the Patchliner (Nanion Technologies GmbH) APC platform. We developed a two-step cell preparation protocol that yielded cell catch rates and whole-cell breakthroughs of ∼80%, with ∼40% of these cells allowing electrical activity to be recorded. The protocol permitted formation of long-lasting (>15 min), high quality seals (>2 GΩ) in both voltage- and current-clamp modes. This enabled density of sodium, calcium, and potassium currents to be evaluated, along with dose-response curves to their respective channel inhibitors, tetrodotoxin, nifedipine, and E-4031. Thus, we show the feasibility of using the Patchliner platform for automated evaluation of the electrophysiology and pharmacology of hPSC-CMs, which will enable considerable increase in throughput for reliable and efficient drug evaluation. [ABSTRACT FROM AUTHOR]

The article examines the interaction between Gram-positive bacterial superantigens and toll-like receptor 2 (TLR2) in health and critical illness. The authors report that superantigens up-regulate monocyte surface TLR2 expression through major histocompatibility complex class II signaling. The authors add that enhanced surface TLR2 expression may be a specific feature of patients with Streptococcus pyogenes-induce shock.

Lethal necrotizing fasciitis caused by Streptococcus pyogenes is characterized by a paucity of neutrophils at the site of infection. Interleukin (IL)-8, which is important for neutrophil transmigration and activation, can be degraded by S. pyogenes. Blood isolates of S. pyogenes were better able to degrade human IL-8 than throat isolates. Degradation of IL-8 was the result of a single specific cleavage between 59glutamine and 60arginine within the IL-8 C-terminal α helix. Cleaved IL-8 reduced neutrophil activation and migration. IL-8-cleaving activity was found in partially purified supernatant of a necrotizing fasciitis isolate, and this activity was associated with an ∼150-kDa fraction containing S. pyogenes cell envelope proteinase (SpyCEP). IL-8-cleaving activity corresponded with the presence of SpyCEP in the supernatant. Cleavage of IL-8 by S. pyogenes represents an unprecedented mechanism of immune evasion, effectively preventing IL-8 C-terminus-mediated endothelial translocation and subsequent recruitment of neutrophils. [ABSTRACT FROM AUTHOR]

The use of microarrays in the analysis of gene expression is becoming widespread for many organisms, including yeast. However, although the genomes of a number of filamentous fungi have been fully or partially sequenced, microarray analysis is still in its infancy in these organisms. Here, we describe the construction and validation of microarrays for the fungus Aspergillus nidulans using PCR products from a 4092 EST conidial germination library. An experiment was designed to validate these arrays by monitoring the expression profiles of known genes following the addition of 1% (w/v) glucose to wild-type A. nidulans cultures grown to mid-exponential phase in Vogel’s minimal medium with ethanol as the sole carbon source. The profiles of genes showing statistically significant differential expression following the glucose up-shift are presented and an assessment of the quality and reproducibility of the A. nidulans arrays discussed. [Copyright &y& Elsevier]

Examines the accumulation of stress and inducer-dependent plant-cell-wall-degrading enzymes in Aspergillus nidulans during asexual development. Interpretation of fungal gene expression profiles based on digital reconstruction of expressed sequence tags; Metabolism functions associated with the transcripts; Cause of the accumulation of stress.