Microstructure and mechanical properties of sintered (2-4)Mn-(0¿6.-0¿8)C steels

YesMechanical properties of 2¿4% manganese PM steels were determined in tension and in bending following laboratory sintering in dry, hydrogen rich atmospheres. Young's modulus determined by an extensometric technique was about 115 GPa; when measured by an ultrasonic method it was about 153 GPa, in accordance with the`law of mixtures¿. The microstructures, significantly devoid of oxide networks, were predominantly pearlitic, but frequently with variability for specimens similarly processed, resulting in appreciable variations in the stresses for macroscopic yielding and fracture. The majority of the experiments were conducted on 3 and 4Mn¿0·6C alloys and for these R0·1 was in the range 275¿500 MPa, tensile strength (TS) 300¿600 MPa, and (apparent) transverse rupture strength (TRS) 640¿1260 MPa. Statistical techniques were employed to analyse the data. When careful control of processing was maintained, the Weibull modulus was highest, at about 17, for TS of furnace cooled specimens, and lowest, about 6, for TRS of the rapidly cooled specimens. In order to interpret the significant differences between the TRS and the TS values, both apparently measuring the critical stress for cracking after strains of up to 7%, a two stage normalising technique for TRS was adopted. By taking account of the plastic strains preceding failure, the elastic`strength of materials¿ formula was modified to allow true fracture stresses to be calculated. It was also postulated that failure was initiated from a population of flaws of variable size and then the `normalised¿ bend strengths, smaller than TRSs, were shown to correspond well with TSs. It is suggested that this combined plasticity correction and Weibull analysis approach, which has a sound scientific basis, should be employed to interpret bend test data in preference to empirical correlations between TS and TRS

Investigation of methods for loss of mains detection for domestic scale distributed generation

PhD ThesisThe drive to lower the environmental impact of power generation has underlined the importance of distributed generation (DG). DG allows a multitude of dispersed renewable technologies to be included within the energy supply network. The energy generation of a DG installation doesn’t necessarily coincide with local power consumption; grid connec- tion allows surplus local power to be distributed using the wider power network. This results in a variety of DG units requiring grid connection. A power electronics interface is commonly needed to achieve connection between the DG unit and the distribution network. Whilst DG units are available in a multitude of sizes, the focus of this work is domestic scale DG. Single phase power inverters are commonly used to connect DG units to the utility. An issue associated with the interconnection of generators within the distribution network is the formation of power islands. A power island is defined as a section of the power network, consisting of generators and loads, which becomes electrically isolated from the wider power network. The majority of grid connection standards stipulate that the grid con- nection power electronics interface must include a robust loss of mains (LOM) detection routine. Once a LOM event has been detected the output power of the DG unit must be reduced to zero to guarantee no power island exists. This thesis details the work carried out during the completion of an En- gineering Doctorate (EngD) Degree in Power Electronics, Machines and Drives. A low voltage laboratory test bench and associated simulation model have been designed and constructed to allow multiple in-the-loop based LOM detection methods to be presented, analysed and compared. A new LOM detection technique has been created, referred to as the proposed technique. The proposed technique is a hybrid LOM detection technique which uses a passive routine to signal when a LOM event may have occurred and an active technique to confirm the LOM event. The passive routine uses Fourier analysis to constantly monitor the magni- tude and spread of high frequency voltage components present at the DG unit connection point. The active confirmation routine is an active power shift function. A fully rated 500W laboratory test bench was created which allows the proposed technique to be verified at power levels more realistic for a standard DG unit installation.Narec: EPSRC

Relationship between community drug administration strategy and changes in trachoma prevalence, 2007 to 2013

Australia is the only high income country with persisting endemic trachoma and a national control program has been in place since 2006. The program involves annual screening of children for trachoma in communities designated to be at high risk of disease and treatment of those affected with the antibiotic azithromycin. Depending on the level of trachoma detected in children, antibiotic treatment is also given to households and other community members. We used data collected annually from 2007 to 2013 to examine what effect the extent of azithromycin treatment had on subsequent levels of trachoma in children aged 5–9 years. We found that in communities with high levels of trachoma, when all community members received azithromycin (community-wide treatment), the greatest reduction in trachoma level was achieved. However in communities with moderate levels of trachoma, using either community-wide treatment or more targeted (household) treatment resulted in equivalent reductions in trachoma. This observation needs to be confirmed in other studies before changes to current recommendations regarding trachoma control strategies are considered

Opinion piece: non-traditional practical work for traditional campuses

Traditional practical work for higher education in STEM subjects is under pressure from rising student numbers and adesired increase in active learning. Investing in more buildings and staff is financially challenging, while stretching existing resources affects outcomes, health, and participation. A more pragmatic approach is to embrace a less instrumentalist view of practical work in physical spaces and instead adopt a critical post-humanist approach which mixes both humanity and technology to achieve a sum greater than the parts, not bound by the limits of either. We share the experiences of leading UK exponents of non-traditional laboratories in the four main categories of simulation, virtual laboratories, real-asynchronous, and real- synchronous activities, as well as experts in scaling digital education initiatives for university-wide adoption. We foreshadow opportunities, challenges and potential solutions to increasing the opportunity for active learning by students studying at traditional campuses, via the complementary addition of non-traditional practical work

A Development Methodology for Concurrent Programs

This paper describes a development methodology for the design of concurrent programs that provides a migration path from existing sequential C and FORTRAN programs. These programs may be executed immediately, without change, using the entire physical memory of a distributed memory machine or a network of ATM-coupled shared-memory multiprocessors. Subsequent program refinements may involve data and control decomposition together with explicit message passing to improve performance. Each step in the program development may utilize new hardware mechanisms supporting shared memory, segmentation and protection. The ideas presented in this paper are currently being implemented within the Multiflow compiler which is being targetted for the M-Machine. Although the examples we present use the C programming language, the concepts will also be available in FORTRAN

Missed opportunities for diagnosing brain tumours in primary care: a qualitative study of patient experiences.

BACKGROUND: Brain tumours are uncommon, and have extremely poor outcomes. Patients and GPs may find it difficult to recognise early symptoms because they are often non-specific and more likely due to other conditions. AIM: To explore patients' experiences of symptom appraisal, help seeking, and routes to diagnosis. DESIGN AND SETTING: Qualitative study set in the East and North West of England. METHOD: In-depth interviews with adult patients recently diagnosed with a primary brain tumour and their family members were analysed thematically, using the Model of Pathways to Treatment as a conceptual framework. RESULTS: Interviews were carried out with 39 patients. Few participants (n = 7; 18%) presented as an emergency without having had a previous GP consultation; most had had one (n = 15; 38%), two (n = 9; 23%), or more (n = 8; 21%) GP consultations. Participants experienced multiple subtle 'changes' rather than 'symptoms', often noticed by others rather than the patient, which frequently led to loss of interest or less ability to engage with daily living activities. The most common changes were in cognition (speaking, writing, comprehension, memory, concentration, and multitasking), sleep, and other 'head feelings' such as dizziness. Not all patients experienced a seizure, and few seizures were experienced 'out of the blue'. Quality of communication in GP consultations played a key role in patients' subsequent symptom appraisal and the timing of their decision to re-consult. CONCLUSION: Multiple subtle changes and frequent GP visits often precede brain tumour diagnosis, giving possible diagnostic opportunities for GPs. Refined community symptom awareness and GP guidance could enable more direct pathways to diagnosis, and potentially improve patient experiences and outcomes

High PD-1/PD-L1 Checkpoint Interaction Infers Tumor Selection and Therapeutic Sensitivity to Anti-PD-1/PD-L1 Treatment

Many cancers are termed immunoevasive due to expression of immunomodulatory ligands. Programmed death ligand-1 (PD-L1) and cluster of differentiation 80/86 (CD80/86) interact with their receptors, programmed death receptor-1 (PD-1) and cytotoxic T-lymphocyte antigen-4 (CTLA-4), respectively, on tumor-infiltrating leukocytes eliciting immunosuppression. Immunotherapies aimed at blocking these interactions are revolutionizing cancer treatments, albeit in an inadequately described patient subset. To address the issue of patient stratification for immune checkpoint intervention, we quantitatively imaged PD-1/PD-L1 interactions in tumor samples from patients, employing an assay that readily detects these intercellular protein-protein interactions in the less than or equal to 10 nm range. These analyses across multiple patient cohorts demonstrated the intercancer, interpatient, and intratumoral heterogeneity of interacting immune checkpoints. The PD-1/PD-L1 interaction was not correlated with clinical PD-L1 expression scores in malignant melanoma. Crucially, among anti-PD-1-treated patients with metastatic non-small cell lung cancer, those with lower PD-1/PD-L1 interaction had significantly worsened survival. It is surmised that within tumors selecting for an elevated level of PD-1/PD-L1 interaction, there is a greater dependence on this pathway for immune evasion and hence, they exhibit more impressive patient response to intervention. SIGNIFICANCE: Quantitation of immune checkpoint interaction by direct imaging demonstrates that immunotherapy-treated patients with metastatic NSCLC with a low extent of PD-1/PD-L1 interaction show significantly worse outcome.This work was supported, in part, by Department of Education, Basque Government- IT1270-19, Elkartek grant (BG18), and the Spanish Ministry grant (MINECO) PROJECTS of EXCELLENCE (BFU2015-65625-P). P.J. Parker was supported by a core grant to the Francis Crick Institute, from Cancer Research UK (FC001130), the UK Medical Research Council (FC001130), and the Wellcome Trust (FC001130).Peer reviewe

The structural basis of bacterial manganese import

肺炎球菌が細胞内にマンガンイオンを取り込むしくみ --膜輸送体PsaBCの立体構造の解明--. 京都大学プレスリリース. 2021-09-15.Metal ions are essential for all forms of life. In prokaryotes, ATP-binding cassette (ABC) permeases serve as the primary import pathway for many micronutrients including the first-row transition metal manganese. However, the structural features of ionic metal transporting ABC permeases have remained undefined. Here, we present the crystal structure of the manganese transporter PsaBC from Streptococcus pneumoniae in an open-inward conformation. The type II transporter has a tightly closed transmembrane channel due to “extracellular gating” residues that prevent water permeation or ion reflux. Below these residues, the channel contains a hitherto unreported metal coordination site, which is essential for manganese translocation. Mutagenesis of the extracellular gate perturbs manganese uptake, while coordination site mutagenesis abolishes import. These structural features are highly conserved in metal-specific ABC transporters and are represented throughout the kingdoms of life. Collectively, our results define the structure of PsaBC and reveal the features required for divalent cation transport