Connection between Mechanical Relaxation and Equilibration Kinetics in a High-Entropy Metallic Glass.

The slow transition from an out-of-equilibrium glass towards a supercooled liquid is a complex relaxation phenomenon. In this Letter, we study the correlation between mechanical relaxation and equilibration kinetics in a Pd_{20}Pt_{20}Cu_{20}Ni_{20}P_{20} high-entropy metallic glass. The evolution of stress relaxation with aging time was obtained with an unprecedented detail, allowing us to pinpoint new interesting features. The long structural relaxation towards equilibrium contains a wide distribution of activation energies, instead of being just associated to the ß relaxation as commonly accepted. The stress relaxation time can be correlated with the equilibration rate and we observe a decrease of microstructural heterogeneity which contrasts with an increase of dynamic heterogeneity. These results significantly enhance our insight of the interplay between relaxation dynamics and thermodynamics in metallic glasses.

Erratum: Intrinsic Correlation between the Fraction of Liquidlike Zones and the ß Relaxation in High-Entropy Metallic Glasses [Phys. Rev. Lett. 129, 175501 (2022)].

This corrects the article DOI: 10.1103/PhysRevLett.129.175501.

Intrinsic Correlation between the Fraction of Liquidlike Zones and the ß Relaxation in High-Entropy Metallic Glasses.

Lacking the structural information of crystalline solids, the origin of the relaxation dynamics of metallic glasses is unclear. Here, we report the evolution of stress relaxation of high-entropy metallic glasses with distinct ß relaxation behavior. The fraction of liquidlike zones, determined at each temperature by the intensity of stress decay, is shown to be directly related to both the aging process and the spectrum of relaxation modes obtained by mechanical spectroscopy. The results shed light on the intrinsic correlation between the static and dynamic mechanical response in high-entropy and conventional metallic glasses, pointing toward a sluggish diffusion high-entropy effect in the liquid dynamics.

A highly distorted ultraelastic chemically complex Elinvar alloy.

The development of high-performance ultraelastic metals with superb strength, a large elastic strain limit and temperature-insensitive elastic modulus (Elinvar effect) are important for various industrial applications, from actuators and medical devices to high-precision instruments1,2. The elastic strain limit of bulk crystalline metals is usually less than 1 per cent, owing to dislocation easy gliding. Shape memory alloys3-including gum metals4,5 and strain glass alloys6,7-may attain an elastic strain limit up to several per cent, although this is the result of pseudo-elasticity and is accompanied by large energy dissipation3. Recently, chemically complex alloys, such as 'high-entropy' alloys8, have attracted tremendous research interest owing to their promising properties9-15. In this work we report on a chemically complex alloy with a large atomic size misfit usually unaffordable in conventional alloys. The alloy exhibits a high elastic strain limit (approximately 2 per cent) and a very low internal friction (less than 2 × 10-4) at room temperature. More interestingly, this alloy exhibits an extraordinary Elinvar effect, maintaining near-constant elastic modulus between room temperature and 627 degrees Celsius (900 kelvin), which is, to our knowledge, unmatched by the existing alloys hitherto reported.

A family history of knee joint replacement increases the progression of knee radiographic osteoarthritis and medial tibial cartilage volume loss over 10 years.

OBJECTIVES: Osteoarthritis (OA) has a genetic component but it is uncertain if the offspring of those with knee OA are at a greater risk. The aim of this study was to describe radiographic OA (ROA) progression and cartilage loss over 10 years in a midlife cohort with some having a family history of OA and some community based controls. METHODS: 220 participants [mean-age 45 (26-61); 57% female] were studied at baseline and 10 years. Half were adult offspring of subjects who underwent knee replacement for OA and the remainder were randomly selected controls. Joint space narrowing (JSN) and osteophytes were assessed on radiographs and cartilage volume (tibial, femoral and patellar), cartilage defects, bone marrow lesions (BMLs) and meniscal tears were assessed on Magnetic resonance imaging (MRI). RESULTS: For ROA, there was a significant difference between offspring and controls in unadjusted analysis for change in total ROA, medial JSN, total medial, total lateral and total osteophyte scores. This difference persisted for medial JSN (difference in ratios = +1.93 (+1.04, +3.51)) only, after adjustment for confounders and baseline differences. In unadjusted analysis for cartilage loss, offspring lost more cartilage at the medial tibial (difference in means = -79.13 (-161.92, +3.71)) site only. This difference became of borderline significance after adjustment for baseline differences (P = 0.055). CONCLUSION: The offspring of subjects having a total knee replacement have a greater worsening of ROA (both JSN and osteophytes) and higher medial tibial cartilage volume loss over 10 years. Most of these changes are mediated by differences in baseline characteristics of offspring and controls except for increase in medial JSN.

Feeding resistance after parenteral hyperalimentation.

Infants requiring prolonged hyperalimentation for a variety of conditions may experience difficulty in establishing oral feedings. Indeed, active resistance to oral feeding is often observed. We describe an infant who was deprived of normal oral feedings for the first ten months of life. Because subsequent feeding resistance was apparently due to behavioral and developmental factors, we suggest that the approach to such cases should involve particular attention to these areas. The child development literature and our surgical experience with esophageal atresia give supporting evidence.

[Lipoma of the small intestine revealed by ileocaecal intussusception (author's transl)]. / Lipome de la dernière anse grêle révélé par une invagination intestinale aiguë.

The authors report a personal case of ileocaecal intussusception in an adult, revealing a benign lipoma of the last ileal loop. A review of the available bibliography was made emphasizing the essential characteristics of this rare type of lesion.

[Inflammatory pseudo-tumors of appendiceal origin. Study of twelve cases (author's transl)]. / Pseudo-tumeurs inflammatoires d'origine appendiculaire. Etude de 12 cas.

The authors relate their experience concerning twelve cases of inflammatory pseudo-tumors of appendiceal origin treated during the last five years. Their personal acquisitions are confronted with the literature and they propose a protocole of clinical, roentgenological and intra-operatory diagnosis thus permitting rational and adapted management.