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Both parasitism and social contact are common sources of stress that many gregarious species encounter in nature. Upon encountering such stressors, individuals secrete glucocorticoids and although short-term elevation of glucocorticoids is adaptive, long-term increases are correlated with higher mortality and deleterious reproductive effects. Here, we used an experimental host-parasite system, social rodents Acomys cahirinus and their characteristic fleas Parapulex chephrenis, in a fully-crossed design to test the effects of social contact and parasitism on stress during pregnancy. By analysing faecal glucocorticoid metabolites, we found that social hierarchy did not have a significant effect on glucocorticoid concentration. Rather, solitary females had significantly higher glucocorticoid levels than females housed in pairs. We found a significant interaction between the stressors of parasitism and social contact with solitary, uninfested females having the highest faecal glucocorticoid metabolite levels suggesting that both social contact and infestation mitigate allostatic load in pregnant rodents. Therefore, the increased risk of infestation that accompanies group-living could be outweighed by positive aspects of social contact within A. cahirinus colonies in nature.
Single-phase Fe-Nb and Co-Nb Laves phase alloys were produced by arc melting and levitation melting. By casting the levitation melted alloys in a preheated mould and subsequent slow cooling to room temperature, solid rods of 15 mm in diameter and about 100 mm length of the brittle Laves phases were obtained. Within the extended homogeneity ranges of the NbFe2 and NbCo2 Laves phases, the Vickers hardness was measured in dependence on composition. The results show that the hardness has a maximum at the stoichiometric composition in both systems, indicating defect softening. Nanoindentation measurements on a Co-Nb diffusion couple confirm the dependence of the hardness on composition. In addition, these measurements indicate that the crystal structure of the Laves phase polytype – cubic or hexagonal – seems to have no effect on the hardness. Indentation fracture toughness KIC-IF data for the different polytypes of the Laves phases were evaluated from the Palmquist cracks originating from the edges of the Vickers indentations.
Transcranial direct current stimulation (tDCS) is a non-pharmacological intervention for depression. It has mixed results, possibly caused by study heterogeneity.
To assess tDCS efficacy and to explore individual response predictors.
Systematic review and individual patient data meta-analysis.
Data were gathered from six randomised sham-controlled trials, enrolling 289 patients. Active tDCS was significantly superior to sham for response (34% v. 19% respectively, odds ratio (OR) = 2.44, 95% CI 1.38–4.32, number needed to treat (NNT) = 7), remission (23.1% v. 12.7% respectively, OR = 2.38, 95% CI 1.22–4.64, NNT = 9) and depression improvement (B coefficient 0.35, 95% CI 0.12–0.57). Mixed-effects models showed that, after adjustment for other predictors and confounders, treatment-resistant depression and higher tDCS ‘doses' were, respectively, negatively and positively associated with tDCS efficacy.
The effect size of tDCS treatment was comparable with those reported for repetitive transcranial magnetic stimulation and antidepressant drug treatment in primary care. The most important parameters for optimisation in future trials are depression refractoriness and tDCS dose.
To describe a useful technique for infiltrating a bulking agent using a butterfly needle, as part of a transoral endoscopic vocal fold medialisation procedure.
This paper describes the procedure of grasping the needle with phonosurgery forceps and administering the injectate to the vocal fold through careful application of the syringe plunger via a length of rubber tubing from outside the mouth.
This procedure is performed routinely in our institution without complication. The advantages of this technique are discussed.
This is a safe and easy method of injecting into a vocal fold.
Fe-Al alloys with about 55 to 65 at.% Al undergo a eutectoid transformation at 1095 °C: Fe5Al8 (ε) ↔ FeAl + FeAl2. Hence, as-cast Fe-Al alloys in this composition range show a very fine-scaled lamellar microstructure (average lamellar spacing below 500 nm) consisting of the two phases FeAl and FeAl2. The microstructure looks similar to the α2 + γ lamellar microstructure of Ti-Al-based alloys, which is known for having well-balanced properties in terms of creep, ductility and strength. However, there is limited knowledge about the properties of Fe-Al-based alloys in this composition range. In this study, a series of as-cast as well as heat-treated Fe-Al alloys with compositions between 57 and 63 at.% Al were investigated. The microstructures and crystal structures were analysed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The composition dependence of all transition temperatures was obtained by differential thermal analysis (DTA).
Treatment for metastatic cutaneous head and neck squamous cell carcinoma is usually multimodal and associated with morbidity. This study aimed to evaluate the impact of treatment on patients' quality of life.
Cross-sectional survey of 42 patients (35 men, 7 women) at least 6 months after metastatic cutaneous head and neck squamous cell carcinoma treatment, using two standardised quality of life questionnaires: the Functional Assessment of Cancer Therapy – Head and Neck questionnaire and the Facial Disability Index, with statistical analysis to identify potential predictors of outcome.
Female gender correlated with significantly lower Facial Disability Index physical function scores (p = 0.017). Alcohol consumption correlated with significantly better scores for Functional Assessment social well-being (p = 0.016), general total score (p = 0.041) and overall total score (p = 0.033), and for Facial Disability Index physical function (p = 0.034). Marital status, education, employment, chemotherapy, time from last treatment, parotidectomy and facial nerve sacrifice did not affect quality of life. The commonest patient complaints were dry mouth (76 per cent), altered voice quality and strength (55 per cent), and physical appearance (45 per cent).
Female gender predicts worse quality of life, while alcohol consumption (versus none) predicted for better quality of life.
A couple of FeAl alloys containing up to 1.4 at.% Li have been produced by vacuum induction melting. Though previous reports indicated a significant effect of Li on the properties of FeAl, no marked changes with respect to binary FeAl are observed. Specifically, no decrease of the lattice constant and no significant increase in ductility are found by alloying with Li. If at all, there is a slight increase of the lattice constant.
This study aimed to compare recurrence and survival in patients undergoing either selective neck dissection or modified radical neck dissection to treat metastatic cutaneous head and neck squamous cell carcinoma to the cervical lymph nodes (levels I–V) only.
Twenty-eight year, retrospective analysis of a prospectively maintained database from a tertiary referral hospital, with a minimum follow up of two years.
There were 122 eligible patients: 96 males (79 per cent) and 26 (21 per cent) females (median age, 66 years). Sixty-six patients (54 per cent) underwent selective neck dissection and 56 (46 per cent) modified radical neck dissection. The former patients had a lower rate of regional recurrence compared with the latter (17 vs 23 per cent, respectively). There was no significant difference in five-year overall survival (61 vs 57 per cent, respectively) or five-year disease-free survival (74 vs 60 per cent, respectively), comparing the two groups. Overall survival and disease-free survival were significantly improved by the addition of adjuvant radiotherapy.
We found no difference in outcome in patients undergoing selective versus modified radical neck dissection. Adjuvant radiotherapy significantly improved outcome.
The martensitic microstructure of shape memory alloys is an aggregate of self accommodating plate groups. The principal character of this aggregate is its demonstration of pseudoplasticity, wherein a macroscopic shape change is brought about by extensive rearrangement and reorientation of the self accommodating martensite variants, and that of microstructural reversibility, wherein the polyvariant microstructure transforms back to the original grain of the parent phase after pseudoplastic deformation. These aspects of the shape memory intermetallic alloys are intriguing and, to a great extent, unsolved. The aim of this paper is to show that the underlying crystallographic interrelationships of the self accommodating microstructure of intermetallic alloys are responsible for the observed effect. The paper will discuss the relation between autocatalytic nucleation and self accommodation, the relation between microstructural reversibility and intervariant interfaces of the martensitic microstructure and the manifestations of microstructural irreversibility using results from the microstructural examination of the self accommodating microstructures.
The aim of this study is two-fold: first we reexamine the thermodynamic stability of γ’-Co3(Al,W) phase in the Co-Al-W ternary system. Secondly, we investigate the effect of a fourth alloying element (Ti or Ta) on the thermodynamic stability of the γ’ phase through microstructure observation, DSC measurement and EPMA analysis. Coarsened areas with γ/CoAl/Co3W phases are formed after annealing at 900 ºC for 2000 h in Co-Al-W ternary alloys with different Al/W ratios, which confirms that the three phases are in equilibrium with each other and that the γ’ phase is metastable at this temperature. The addition of a fourth alloying elements does not drastically change the microstructure formed after long term annealing at 900 ºC, indicating that the alloying elements do not improve the stability of the γ’ phase.
In order to clarify the phase stability of E21-type intermetallic carbides, the maximum solid solubility of carbon in Ni3AlC1-x was evaluated by taking into account the strain energy and the chemical energy for the formation of the Ni6C cluster (EM6C). It was found that the maximum carbon content calculated was 0 at.%C at EM6C≥0, 3.5 at.%C at EM6C = -5 kJ/mol, 6.5 at.%C at EM6C = -10 kJ/mol, 10 at.%C at EM6C = -15 kJ/mol and 13 at.%C at EM6C = -20 kJ/mol, respectively. Experimentally determined maximum carbon contents in Ni3Al in the literature can be explained when EM6C is ranged from -5 to -15 kJ/mol, and the solid solubility is found to be sensitive to EM6C. The attractive interaction between Ni and C seems to be due to covalent bonding. Similar attractive chemical interaction between transition metals and carbon must stabilize E21 phases.
Increasing demands on technical components for high-temperature applications (e.g. tur-bine blades) promote new developments not only in the field of alloy design, but also in surface engineering. This paper shows that it is possible to structure the surface of intermetallic titanium aluminides in-situ by locally controlled oxidation of the material due to selective doping with fluorine. The aim is to reproduce a shark-skin pattern (parallel riblets with valleys in between) in order to improve the surface aerodynamics. Riblets with widths in the single digit μm range have been generated. The nucleation process, the aspect ratio and the stability of the generated micro-structures are discussed as a function of the substrate composition and the oxidation conditions.
Plane wave ab initio density functional theory (DFT) calculations of the B2 NiTi (100), (110), and (111) surfaces, the B2 and B19´ phases of NiTi, and the supercell structures of NiTi, Ni4Ti3 and Ni3Ti are reported. Electronic energies from the electronic structure calculations are used to assess relative stability of the different surface and supercell geometries.
A Mg-Zn-Y alloy including a Mg12ZnY intermetallic compound exhibits excellent mechanical properties as compared to conventional magnesium alloys. The superior mechanical properties of this alloy seem to originate from the Mg12ZnY intermetallic compound; however, the mechanical properties of Mg12ZnY itself have not yet been fully investigated owing to the small size of this compound. In this study, a microfracture test was performed to investigate the fracture properties of the Mg12ZnY intermetallic compound. The material used in this test was a Mg88Zn5Y7 alloy. Micro-sized cantilever specimens composed of Mg12ZnY, with dimensions of 10 × 20 × 50 μm3, were prepared selectively isolated from the Mg88Zn5Y7 alloy using focused ion beam (FIB) machining. Notches with a width of 0.5 μm and a depth of 5 μm were also introduced into the micro-sized specimens. Microfracture tests were performed using a mechanical testing machine for microscale materials. The fracture toughness values (KQ) of Mg12ZnY were 1.2−3.0 MPam1/2. TEM observations indicated that the KQ values were dependent on the crack orientation in Mg12ZnY, with the higher KQ values correlating with cracks propagating parallel to the c-axis of Mg12ZnY. This suggests that the fracture toughness of Mg-Zn-Y alloys can be improved by controlling the orientation of the Mg12ZnY compound.
The site preference of ternary additions in GCP (geometrically close-packed) Ni3X-type compounds with D0a structure was determined from the direction of the single-phase region of the D0a phase in the reported ternary phase diagrams. The thermodynamic model based on the Bragg-Williams approximation, which is based on the change in heat of formation of the host compound by a small addition of ternary solute, was applied to predict the site preference of ternary additions. The heat of formation used in the thermodynamic calculation was derived from Miedema’s formula. Good agreement was obtained between the thermodynamic model and the result of the literature search.
The creep behavior of a new type of austenitic heat-resistant steel Fe-20Cr-30Ni-2Nb (at.%), strengthened by intermetallic Fe2Nb Laves phase, has been examined. Particular attention has been given to the role of grain boundary Laves phase in the strengthening mechanism during long-term creep. The creep resistance increases with increasing area fraction (ρ) of grain boundary Laves phase according to equation ε/ε = (1−ρ), where ε0 is the creep rate at ρ = 0. In addition, the creep rupture life is also extended with increasing ρ without ductility loss, which can yield up to 77% of elongation even at ρ = 89%. Microstructure analysis revealed local deformation and well-developed subgrains formation near the grain boundary free from precipitates, while dislocation pile-ups were observed near the grain boundary Laves phase. Thus, the grain boundary Laves phase is effective in suppressing the local deformation by preventing dislocation motion, and thereby increases the long-term creep rupture strength. This novel creep strengthening mechanism was proposed as “grain boundary precipitation strengthening mechanism” (GBPS).
Phase equilibria among γ-Fe, ε-Fe2Nb Laves and δ-Ni3Nb phases in Fe-Ni-Nb ternary system at 1473 K and 1373 K were experimentally examined, and also assessed by calculation in order to calculate the phase equilibria among these phases at 973 K. A ternary compound with hP24 structure with its limited composition range of Fe-21.5Nb- (56.8-59.8) Ni exists between Fe2Nb and Ni3Nb phase regions at both temperatures. Including the hP24 phase, the calculated isotherms at both temperatures are in good agreement with experimental ones. By using the optimized interaction parameters among the three elements in each phase, the isothermal section calculated at 973 K revealed a γ-Fe+ Fe2Nb + Ni3Nb three-phase coexisting region extended to Fe-rich composition of 80 at. % Fe. This suggests a possibility to develop austenitic heatresistant steels strengthened by both intermetallics phases.
Square-shaped micropillar of nearly stoichiometric TiAl single crystals with various loading axis orientations were prepared from TiAl PST crystals by focused ion beam (FIB) technique and deformed in compression using a micro hardness testing machine equipped with a flat diamond tip in order to investigate the values of CRSS for the three types of operative deformation modes, namely ordinary slip, superlattice slip and twinning. The selective activation of the three types of deformation modes was confirmed to be achieved by compression tests of -oriented single crystalline micropillars, respectively. The average CRSS values for ordinary slip, superlattice slip and deformation twinning obtained for micropillars with an initial side length between 3.8 and 7.9μm were estimated to be about 145, 284 and 113 MPa, respectively.