High-temperature creep of single-crystal nickel-based superalloy : microstructural changes and effects of thermal cycling

Creep tests were performed on MC2 single crystal superalloy at 950°C/200 MPa and 1150°C/80 MPa under isothermal and thermal cycling conditions with a tensile axis along the [0 0 1] direction. It was found that the thermal cycles strongly affect the creep behavior at 1150°C but not at 950°C. This was related to the repetitive precipitation and dissolution of small γ′ rafts at the higher temperature, as revealed by quantitative characterization of the γ/γ′ microstructure. The dislocation microstructure exhibits similar trends in all the tested conditions, with a very high activity of a[1 0 0]-type dislocations climbing through the rafts. Such climbing dislocations constitute a recovery process for the deformation active system. It appears that the density of a[1 0 0] dislocations, and not their climb velocity or diffusion rate, is the key parameter for the control of creep rate. The thermal cycles, which imply the creation and subsequent dissolution of rafts, provided new dislocations, which explains the acceleration of creep observed under such conditions

Influence of oxide films on primary water stress corrosion cracking initiation of alloy 600

In the present study alloy 600 was tested in simulated pressurised water reactor (PWR) primary water, at 360 °C, under an hydrogen partial pressure of 30 kPa. These testing conditions correspond to the maximum sensitivity of alloy 600 to crack initiation. The resulting oxidised structures (corrosion scale and underlying metal) were characterised. A chromium rich oxide layer was revealed, the underlying metal being chromium depleted. In addition, analysis of the chemical composition of the metal close to the oxide scale had allowed to detect oxygen under the oxide scale and particularly in a triple grain boundary. Implication of such a finding on the crack initiation of alloy 600 is discussed. Significant diminution of the crack initiation time was observed for sample oxidised before stress corrosion tests. In view of these results, a mechanism for stress corrosion crack initiation of alloy 600 in PWR primary water was proposed

Loss of strength in Ni3Al at elevated temperatures

Stress decrease above the stress peak temperature (750 K) is studied in h123i single crystals of Ni3(Al, 3 at.% Hf ). Two thermally activated deformation mechanisms are evidenced on the basis of stress relaxation and strain rate change experiments. From 500 to 1070 K, the continuity of the activation volume/temperature curves reveals a single mechanism of activation enthalpy 3.8 eV/atom and volume 90 b3 at 810K with an athermal stress of 330 MPa. Over the very same temperature interval, impurity or solute diffusion towards dislocation cores is evidenced through serrated yielding, peculiar shapes of stress–strain curves while changing the rate of straining and stress relaxation experiments. This complicates the identification of the deformation mechanism, which is likely connected with cube glide. From 1070 to 1270 K, the high-temperature mechanism has an activation enthalpy and volume of 4.8 eV/atom and 20 b3, respectively, at 1250 K

Relation between composition, microstructure and oxidation in iron aluminides

The relation between chemical composition, microstructure and oxidation properties has been investigated on various FeAl based alloys, the aim being to induce changes in the microstructure of the compound by selective oxidation of aluminium. Oxidation kinetics that was evaluated on bulk specimens showed that, due to fast diffusion in the alloys, no composition gradient is formed during the aluminium selective oxidation. Accordingly, significant aluminium depletion in the compound could be observed in the thinnest part of oxidised wedge-shape specimens. Another way to obtain samples of variable aluminium content was to prepare diffusion couples with one aluminide and pure iron as end members. These latter specimens have been characterised using electron microscopy and first results of oxidation experiments are presented

Correspondences, an exhibition of installations : Peter Burgess et al

Correspondences, an exhibition of installations : Peter Burgess et al Catalogue of Exhibition held at the Tasmanian School of Art, University of Tasmania 4 July-20 July, 1984 Works by Peter Burgess, Peter Callas, Adrian Hall, Maryrose Sinn, Gregory Smith, Neil Stevenson, Alain Viguier, John Youn

Size and shape constancy in consumer virtual reality

With the increase in popularity of consumer virtual reality headsets, for research and other applications, it is important to understand the accuracy of 3D perception in VR. We investigated the perceptual accuracy of near-field virtual distances using a size and shape constancy task, in two commercially available devices. Participants wore either the HTC Vive or the Oculus Rift and adjusted the size of a virtual stimulus to match the geometric qualities (size and depth) of a physical stimulus they were able to refer to haptically. The judgments participants made allowed for an indirect measure of their perception of the egocentric, virtual distance to the stimuli. The data show under-constancy and are consistent with research from carefully calibrated psychophysical techniques. There was no difference in the degree of constancy found in the two headsets. We conclude that consumer virtual reality headsets provide a sufficiently high degree of accuracy in distance perception, to allow them to be used confidently in future experimental vision science, and other research applications in psychology

Integrated microfluidic tmRNA purification and real-time NASBA device for molecular diagnostics.

We demonstrate the first integrated microfluidic tmRNA purification and nucleic acid sequence-based amplification (NASBA) device incorporating real-time detection. The real-time amplification and detection step produces pathogen-specific response in < 3 min from the chip-purified RNA from 100 lysed bacteria. On-chip RNA purification uses a new silica bead immobilization method. On-chip amplification uses custom-designed high-selectivity primers and real-time detection uses molecular beacon fluorescent probe technology; both are integrated on-chip with NASBA. Present in all bacteria, tmRNA (10Sa RNA) includes organism-specific identification sequences, exhibits unusually high stability relative to mRNA, and has high copy number per organism; the latter two factors improve the limit of detection, accelerate time-to-positive response, and suit this approach ideally to the detection of small numbers of bacteria. Device efficacy was demonstrated by integrated on-chip purification, amplification, and real-time detection of 100 E. coli bacteria in 100 microL of crude lysate in under 30 min for the entire process

Expression of Foxp3 in colorectal cancer but not in Treg cells correlates with disease progression in patients with colorectal cancer

Background: Regulatory T cells (Treg) expressing the transcription factor forkhead-box protein P3 (Foxp3) have been identified to counteract anti-tumor immune responses during tumor progression. Besides, Foxp3 presentation by cancer cells itself may also allow them to evade from effector T-cell responses, resulting in a survival benefit of the tumor. For colorectal cancer (CRC) the clinical relevance of Foxp3 has not been evaluated in detail. Therefore the aim of this study was to study its impact in colorectal cancer (CRC). Methods and Findings: Gene and protein analysis of tumor tissues from patients with CRC was performed to quantify the expression of Foxp3 in tumor infiltrating Treg and colon cancer cells. The results were correlated with clinicopathological parameters and patients overall survival. Serial morphological analysis demonstrated Foxp3 to be expressed in cancer cells. High Foxp3 expression of the cancer cells was associated with poor prognosis compared to patients with low Foxp3 expression. In contrast, low and high Foxp3 level in tumor infiltrating Treg cells demonstrated no significant differences in overall patient survival. Conclusions: Our findings strongly suggest that Foxp3 expression mediated by cancer cells rather than by Treg cells contribute to disease progression

Long-Term Impact of Cyclosporin Reduction with MMF Treatment in Chronic Allograft Dysfunction: REFERENECE Study 3-Year Follow Up

Calcineurin inhibitor (CNI) toxicity contributes to chronic allograft nephropathy (CAN). In the 2-year, randomized, study, we showed that 50% cyclosporin (CsA) reduction in combination with mycophenolate mofetil (MMF) treatment improves kidney function without increasing the risk for graft rejection/loss. To investigate the long-term effect of this regimen, we conducted a follow up study in 70 kidney transplant patients until 5 years after REFERENCE initiation. The improvement of kidney function was confirmed in the MMF group but not in the control group (CsA group). Four graft losses occurred, 2 in each group (graft survival in the MMF group 95.8% and 90.9% in control group). One death occurred in the control group. There was no statistically significant difference in the occurrence of serious adverse events or acute graft rejections. A limitation is the weak proportion of patient still remaining within the control group. On the other hand, REFERENCE focuses on the CsA regimen while opinions about the tacrolimus ones are still debated. In conclusion, CsA reduction in the presence of MMF treatment seems to maintain kidney function and is well tolerated in the long term

Efficacy and safety of abrocitinib in patients with severe and/or difficult-to-treat atopic dermatitis: a post hoc analysis of the randomized phase 3 JADE COMPARE trial

Background: Traditional systemic immunosuppressants and advanced therapies improve signs and symptoms of moderate-to-severe atopic dermatitis (AD). However, data are limited in severe and/or difficult-to-treat AD. In the phase 3 JADE COMPARE trial of patients with moderate-to-severe AD receiving background topical therapy, once-daily abrocitinib 200 mg and 100 mg showed significantly greater reductions in the symptoms of AD than placebo and significantly greater improvement in itch response (with abrocitinib 200 mg) than dupilumab at week 2. Objective: This study assessed the efficacy and safety of abrocitinib and dupilumab in a subset of patients with severe and/or difficult-to-treat AD in a post hoc analysis of the JADE COMPARE trial. Methods: Adults with moderate-to-severe AD received once-daily oral abrocitinib 200 mg or 100 mg, dupilumab 300 mg subcutaneous injection every 2 weeks, or placebo with concomitant medicated topical therapy. Severe and/or difficult-to-treat AD subgroups were classified by baseline characteristics [Investigator’s Global Assessment (IGA) 4, Eczema Area and Severity Index (EASI) > 21, failure or intolerance to prior systemic agents (excluding patients who took only corticosteroids), percentage of body surface area (%BSA) > 50, upper quartiles of EASI (EASI > 38) and %BSA (%BSA > 65), and combined subgroup of IGA 4, EASI > 21, and %BSA > 50, and failure or intolerance to prior systemic agents (excluding patients who took only corticosteroids)]. Assessments included IGA score of 0 (clear) or 1 (almost clear) and a ≥ 2-point improvement from baseline, ≥ 75% and ≥ 90% improvement from baseline in EASI (EASI-75 and EASI-90), ≥ 4-point improvement from baseline in Peak Pruritus-Numerical Rating Scale (PP-NRS4), time to PP-NRS4, least squares mean (LSM) change from baseline in 14-day PP-NRS (days 2–15), Patient-Oriented Eczema Measure (POEM), and Dermatology Life Quality Index (DLQI) up to week 16. Results: The proportion of patients achieving IGA 0/1, EASI-75, and EASI-90 responses was significantly greater with abrocitinib 200 mg than placebo (nominal p < 0.05) across all subgroups with severe and/or difficult-to-treat AD. Across most subgroups, PP-NRS4 response was significantly greater with abrocitinib 200 mg than placebo (nominal p < 0.01); the time to achieve this response was shorter with abrocitinib 200 mg (range 4.5–6.0 days) than abrocitinib 100 mg (range 5.0–17.0 days), dupilumab (range 8.0–11.0 days), and placebo (range 3.0–11.5 days). LSM change from baseline in POEM and DLQI was significantly greater with abrocitinib 200 mg than placebo (nominal p < 0.001) across all subgroups. Clinically meaningful differences were observed between abrocitinib and dupilumab for most evaluated endpoints across several subgroups, including in patients who failed or were intolerant to prior systemic therapy. Conclusions: Abrocitinib provided rapid and substantially greater improvements in skin clearance and quality of life compared with placebo and dupilumab in subgroups of patients with severe and/or difficult-to-treat AD. These findings support the use of abrocitinib for severe and/or difficult-to-treat AD. Trial registration:: ClinicalTrials.gov, NCT03720470