Unusual Deformation Research Articles

Lipoblastomatosis appearing as an unusual symmetric upper lip deformity

We report an unusual case of a bilateral, symmetric upper lip deformity. The submucosal tissue of the resected redundant portion of the lip was occupied by a mass that was diagnosed histopathologically as lipoblastomatosis. Differential diagnoses of lesions with symmetric upper lip deformity and current controversy regarding the surgical treatment are discussed here.

Co‐occurring SHOC2 and PTPN11 mutations in a patient with severe/complex Noonan syndrome‐like phenotype

Noonan syndrome (NS) is a heterogeneous disorder caused by activating mutations in the RAS-MAPK signaling pathway. It is associated with variable clinical expression including short stature, congenital heart defect, unusual pectus deformity, and typical facial features and the inheritance is autosomal dominant. Here, we present a clinical and molecular characterization of a patient with Noonan-like syndrome with loose anagen hair phenotype and additional features including mild psychomotor developmental delay, osteoporosis, gingival hyperplasia, spinal neuroblastoma, intrathoracic extramedullary hematopoiesis, and liver hemangioma. Mutation analysis of PTPN11, SOS1, RAF1, KRAS, BRAF, MEK1, MEK2, NRAS, and SHOC2 was conducted, revealing a co-occurrence of two heterozygous previously identified mutations in the index patient. The mutation SHOC2 c.4A > G; p.Ser2Gly represents a de novo mutation, whereas, PTPN11 c.1226G > C; p.Gly409Ala was inherited from the mother and also identified in the brother. The mother and the brother present with some NS manifestations, such as short stature, delayed puberty, keratosis pilaris, café-au-lait spots, refraction error (mother), and undescended testis (brother), but no NS facial features, supporting the notion that the PTPN11 p.Gly409Ala mutation leads to a relatively mild phenotype. We propose that, the atypical phenotype of the young woman with NS reported here is an additive effect, where the PTPN11 mutation acts as a modifier. Interestingly, co-occurrence of RAS-MAPK mutations has been previously identified in a few patients with variable NS or neurofibromatosis-NS phenotypes. Taken together, the results suggest that co-occurrence of mutations or modifying loci in the RAS-MAPK pathway may contribute to the clinical variability observed among NS patients.

Relation between icosahedral short-range ordering and plastic deformation in Zr–Nb–Cu–Ni–Al bulk metallic glasses

The relation between icosahedral short-range ordering (ISRO) and plastic deformation was investigated in Zr 70− x Nb x Cu 13.5Ni 8.5Al 8 (at.%, x = 0, 2, 4, 6, 7, 8, 10) bulk metallic glasses (BMG). The formation of icosahedral quasicrystal (I-phase) during the annealing process implies that ISRO widely exists in these materials. The degree of ISRO is thermodynamically evaluated to show that ISRO increases with increasing Nb content. Compression tests indicate that BMG with 0–7 at.% Nb possess similar unusual plastic deformability, which is attributed to ISRO-mediated local distribution of free volume (FV) and ISRO prompted deformation-induced crystallization. A proposed core–shell model coupled with transmission electron microscopy analysis demonstrates that the FV is distributed more heterogeneously with increasing ISRO, which is beneficial for multiplying the shear bands. Deformation-induced crystallization is facilitated, owing to the low interfacial energy of the nucleation and growth of the crystals attributed to ISRO in the amorphous matrix, which improves plasticity by consuming energy and the product altering the stress field in the amorphous matrix. Design of new ductile BMG is discussed in these strategies.

Development of Ni- and Cu-Free Zr-Based Bulk Metallic Glasses for Biomedical Applications

Two Ni- and Cu-free bulk metallic glasses (BMGs) of Zr65Pd17:5Fe10Al7:5 and Zr65Pd12:5Ag5Fe10Al7:5, with a critical casting diameter of 6 mm and a compressive strength above 1500 MPa, were developed. While the Zr65Pd17:5Fe10Al7:5 alloy showed little plastic strain before fracture, the Zr65Pd12:5Ag5Fe10Al7:5 alloy exhibited much larger plasticity by the relatively stable, intermittent propagation of the major shear band under compression. This unusual plastic deformation behavior was interpreted on the basis of the contribution of the icosahedral shortrange order. Potentiodynamic polarization tests revealed that the Zr65Pd12:5Ag5Fe10Al7:5 alloy has a higher corrosion resistance than the Zr65Pd17:5Fe10Al7:5 alloy in phosphate buffered saline at 37 � C. X-ray photoelectron spectroscopy analysis revealed that the passive film of Zr65Pd12:5Ag5Fe10Al7:5 alloy consisted mostly of ZrO2, which may be responsible for the excellent corrosion resistance of this alloy. Ni- and Cufree BMGs with a critical diameter of 6 mm, together with enhanced mechanical properties and corrosion resistance, may be promising in biomedical applications. [doi:10.2320/matertrans.M2010068]

Deformation and structural densification in Al 2O 3–Y 2O 3 glass

In this article, we examine the unusual plastic deformation under uniaxial compression of an Al 2O 3–15 mol.% Y 2O 3 (A15Y) glass synthesized by a wet chemical route. At a low temperature of 650–725 °C, plastic deformation of this glass is largely non-viscous through shear instabilities. In contrast, deformation near the crystallization temperature (850 °C) occurs homogeneously with work hardening and with a monotonic increase in the true density of the glass by 10–12%, accompanied by an increase in hardness ( H) and elastic modulus ( E) of up to 100%. We hypothesize a phenomenon of molecular densification of the amorphous structure through a hierarchy of multiple phases, analogous to density- or entropy-driven amorphous-to-amorphous phase transitions (polyamorphism). These results suggest that the present method of preparation and the unusual behavior can trigger a search for many more systems that display such behavior.

Influence of exsolved gases on slope performance at the Sarnia approach cut to the St. Clair Tunnel

In 1993, over 100 years after the completion of the original St. Clair Tunnel and its approach cuts, work commenced on the new St. Clair Tunnel. The new tunnel used the existing approaches, but required additional excavation to widen and deepen the original cuts. In Sarnia, the new work initiated unusual deep-seated deformations on the south slope of the approach. Effective stress finite element analysis (FEA), using an elliptical cap soil model coupled with Biot consolidation theory, was used to model the 1993 construction, but initial predictions were unable to capture the trend of deformations noted in the field. Naturally occurring gases are frequently encountered near the base of the overburden in the Sarnia area and this phenomenon was observed during drilling investigations in the Sarnia approach cut. Including the effects of the presence of exsolved natural gases in fine-grained soils subjected to unloading in the FEA results in substantially better predictions in the trend of deformations on the slopes of the approach cut.

Technical Challenges of Total Knee Arthroplasty in Skeletal Dysplasia

Total knee arthroplasty (TKA) in patients with skeletal dysplasias is particularly challenging as a result of the anatomic variances and substantial bony deformities. Little has been written regarding technical considerations that should be made when performing TKA in skeletal dysplasia. We describe special operative considerations that must be made when performing TKA on patients with skeletal dysplasia, including implant selection and ligamentous balancing. We retrospectively reviewed 12 TKAs in eight patients with varying degrees of deformity (ranging from 30° of varus to 45° of valgus) secondary to three types of skeletal dysplasias: multiple hereditary exostosis, achondroplasia, and osteogenesis imperfecta. Clinical notes, operative records, and radiographic data were reviewed. Minimum followup was 1 year (average, 4 years; range, 1-10 years). We used customized implants in three of the 12 knees. Constrained tibial inserts were used in five knees. All 12 knees underwent releases (soft tissue or epicondylar osteotomy) to address gap balancing or patellar tracking. Average Knee Society scores improved from 35.9 preoperatively to 82.9 postoperatively and average function scores improved from 47.9 preoperatively to 96.7 postoperatively. Complications included two transient peroneal nerve palsies. Special considerations must be made with regard to implant selection and ligamentous balancing as a result of the unusual anatomy and deformities that accompany skeletal dysplasia, but the short-term clinical results reveal consistent improvements in pain and function. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

High Glass-Forming Ability and Unusual Deformation Behavior of New Zr-Cu-Fe-Al Bulk Metallic Glasses

A new series of bulk metallic glasses were developed by addition of Fe into the ternary Zr60Cu30Al10 alloy. Although Fe-Cu element pair shows distinct immiscibility with a large positive heat of mixing, substitution of Fe for Cu significantly improves the glass-forming ability of the ternary Zr60Cu30Al10 alloy. The critical diameter for glass-formation increases from 8 mm for Zr60Cu30Al10 alloy to 20 mm for Zr60Cu25Fe5Al10 and Zr62.5Cu22.5Fe5Al10 alloys. As compared with the ternary Zr60Cu30Al10 alloy, the new quaternary Zr-Cu-Fe-Al alloys show lower liquidus temperatures. The Zr60Cu25Fe5Al10 and Zr62.5Cu22.5Fe5Al10 alloys, the best BMG-formers in this alloy system, are found to locate very near a Zr-Cu-Fe-Al eutectic point. The new Zr-Fe-Cu-Al bulk metallic glasses exhibit high strength of about 1700 MPa. The plastic strain increases from 7.8% to 11.3% with increasing the content of Fe from 0 to 12.5%. The finding of a Ni-free Zr-based bulk glassy alloy with the extremely high glass-forming ability is expected to extend the future application of bulk metallic glasses.

Extreme nuclear shapes examined via giant dipole resonance lineshapes in hot light-mass systems

The influence of alpha clustering on nuclear reaction dynamics is investigated using the giant dipole resonance (GDR) lineshape studies in the reactions 20Ne (Elab=145,160 MeV) + 12C and 20Ne (Elab=160 MeV) + 27Al, populating 32S and 47V, respectively. The GDR lineshapes from the two systems are remarkably different from each other. Whereas, the non alpha-like 47V undergoes Jacobi shape transition and matches exceptionally well with the theoretical GDR lineshape estimated under the framework rotating liquid drop model (RLDM) and thermal shape fluctuation model (TSFM) signifying shape equilibration, for alpha cluster 32S an extended prolate kind of shape is observed. This unusual deformation, seen directly via -decay for the first time, is predicted to be due to the formation of orbiting di-nuclear configuration or molecular structure of 16O+ 16O in 32S superdeformed band.

Unusual plastic deformability in a Zr-based bulk metallic glass after structural relaxation

The structural stability is an essential problem for engineering application of bulk metallic glasses (BMGs). Constant-heating dilatometric measurements were conducted for 2 mm Zr 63.78Cu 14.72Ni 10Al 10Nb 1.5 BMG rods and two visible structural relaxation processes below T g were found, which correspond to the obvious annihilation of free volume (FV) and the continuous decrease in coefficient of linear thermal expansion ( α). After annealing the BMGs near the temperature of the main structural relaxation processes and T g for 3600 s, the BMG rods have much FV relaxed, but still remain the amorphous structure. The microhardness of the annealed samples increases with increasing the annealing temperature, but the plastic strains remain unchanged considering the uncertainty of uniaxial compression after annealing the BMGs at the temperature below T g . The excellent plasticity of the BMGs experienced the structural relaxation is absolutely different from those previous results of embrittlement after structural relaxation below T g . The mechanisms of this unusual plastic deformability for the BMGs experienced the structural relaxation below T g is discussed in the light of apparent activation volume.

Characteristic length scales governing plasticity/brittleness of bulk metallic glasses at ambient temperature

In this letter, we propose a unified theory for the size-dependent plasticity of bulk metallic glasses (BMGs) at room temperature. Based on the principle of energy balance and the shear-banding kinetics, two characteristic length scales are derived. One is a sample-geometry dependent variable related to the elastic energy released to drive shear-band propagation and the other is a material-dependent constant related to the internal resistance to brittle fracture. It is shown that this unified theory is effective in explaining many unusual deformation and fracture behaviors of BMGs.

TANINIZ NEDİR?

A 36-year-old woman presented with an unusual deformity in her hands that began ten years ago. She noticed thermal sensory loss in her hands. On examination, her fingers were thickened, nails deformed, and there were slowly healing ulcers and fissures in her palms (Figure 1). On neurological examination, there was touch, thermal and pain sensory loss limited to her arms. The cranial nerves were normal. Tendon reflexes were normal in the arms, and exaggerated in the legs. Hoffmann and Babinski signs were elicited bilaterally.

Linear bendings of star-like bipyramids

This paper is a revised and an extended version of the article [A.D. Milka, Linear bending of star-like pyramids, Comptes Rendus Mecanique 331 (12) (2003) 805–810]. A family of polyhedra possessing unusual deformation properties is found. On one hand, models of these polyhedra admit free continuous large reversible bendings without visible distortions of the material. On the other hand, the polyhedra themselves are mathematically rigid and do not admit continuous bendings in the sense of O. Cauchy. The found polyhedra are called model flexors in order to distinguish them from theoretical flexors of R. Connelly. Bendings of the models are asymptotically exactly approximated by linear bendings of polyhedra. They represent a non-rigid, soft or retarded, loss of stability which corresponds to the loss of stability “in the small” in the sense of L. Euler. This new phenomenon in mechanics of deformable solid bodies may be considered as an original geometric catastrophe machine which supplements known physical models by E.C. Ziman and T. Poston.

Percutaneous Distraction Osteogenesis for Treatment of Brachymetatarsia

Brachymetatarsia is not an unusual deformity and is often associated with functional and cosmetic issues that warrant surgical reconstruction. Lengthening of the affected metatarsal can be undertaken on an acute basis in a single operative procedure that involves the use of a bone graft or by means of gradual callus distraction. Because of the risk of metatarsophalangeal joint malalignment, it is important for the surgeon to take steps to stabilize the joint during the lengthening process. In this report, a percutaneous method of callus distraction for repair of brachymetatarsia and maintenance of metatarsophalangeal joint alignment is presented.

An efficient constitutive model for room-temperature, low-rate plasticity of annealed Mg AZ31B sheet

Metals and alloys with hexagonal close packed (HCP) crystal structures can undergo twinning in addition to dislocation slip when loaded mechanically. The complexity of the plastic response and the limited extent of twinning are impediments to their room-temperature formability and thus their widespread adoption. In order to exploit the unusual deformation characteristics of twinning sheet materials in designing novel forming operations, a practical plane stress material model for finite element implementation was sought. Such a model, TWINLAW, has been constructed based on three phenomenological deformation modes for Mg AZ31B: S (slip), T (twinning), and U (untwinning). The modes correspond to three testing regimes: initial in-plane tension (from the annealed state), initial in-plane compression, and in-plane tension following compression, respectively. A von Mises yield surface with initial non-zero back stress was employed to account for plastic yielding asymmetry, with evolution according to a novel isotropic and nonlinear kinematic hardening model. Texture and its evolution were represented throughout deformation using a weighted discrete probability density function of c-axis orientations. The orientation of c-axes evolves with twinning or untwinning using explicit rules incorporated in the model. TWINLAW was implemented in Abaqus/Standard through UMAT with constitutive parameters obtained from in-plane tension/compression tests. Simulation of various tests showed good agreement with experiments, where available. Tests to assess the stability of the model for complex loading paths, for which no experimental results were available, have also been carried out. Comparison of computation times showed that TWINLAW is two orders of magnitude faster than a viscoplastic self-consistent polycrystal model incorporating twinning, but an order of magnitude slower than a conventional continuum model with isotropic hardening. TWINLAW reproduces all of the standard and special features of Mg deformation in terms of slip, twinning, and untwinning, for a range of strain states and transitions among such states, but has not been verified for multi-cycle strain paths.

Stable flowing of localized shear bands in soft bulk metallic glasses

Abstract This paper reports a novel class of Zr–Cu–Fe–Al bulk metallic glasses (BMGs) with high Zr content and unusual deformation behavior. Higher content of Zr results in lower hardness, but favors the generation of highly localized shear bands, even if nanocrystalline phases precipitate in the glassy matrix. Moreover, flow of the dominant shear band proceeds slowly under compressive stress without rapid shear rupture and facture. The unusual deformation behavior suggests that designing BMG with a high content of solvent element and low hardness might be a promising new way of developing ductile BMG.

Tensile Deformation and Fracture Mechanism of Bulk Bimodal Ultrafine-Grained Al-Mg Alloy

The tensile fractures of ultrafine-grained (UFG) Al-Mg alloy with a bimodal grain size were investigated at the micro- and macroscale using transmission electron microscopy (TEM), scanning electron microscopy (SEM) equipped with focused ion beam (FIB), and optical microscopy. The nanoscale voids and crack behaviors near the tensile fracture surfaces were revealed in various scale ranges and provided the evidence to determine the underlying tensile deformation and fracture mechanisms associated with the bulk bimodal metals. The bimodal grain structures exhibit unusual deformation and fracture mechanisms similar to ductile-phase toughening of brittle materials. The ductile coarse grains in the UFG matrix effectively impede propagation of microcracks, resulting in enhanced ductility and toughness while retaining high strength. In view of the observations collected, we propose a descriptive model for tensile deformation and fracture of bimodal UFG metals.

Abstract: P1395 EFFECT OF CHOLESTERYL ESTER TRANSFER PROTEIN (CETP) DEFICIENCY ON HDL COMPOSITION AND FUNCTION

Chondrosia reniformis is a common marine demosponge that shows striking tissue plasticity and unusual body deformability. This sponge can develop long and slender outgrowths extending from the parental body. According to some authors, this phenomenon, called “creeping”, can be related to asexual reproduction, atypical mechanisms of «localized» locomotion or passive response to environmental stress. Here we address this phenomenon by means of an interdisciplinary approach consisting of field survey, experimental field studies and experimental laboratory studies. During field survey and field experimental survey we observed that the instability of substratum is an important factor that trigs the beginning of creeping. The sponge size does not seem to be directly involved in the occurrence of the phenomenon. Specimens of Bergeggi (Ligurian Sea, northern Italy) show a high correlation between the creeping phenomenon and the sea temperature; this seems to support the hypothesis that the phenomenon is related to asexual reproduction, which is in its turn seasonally regulated by environmental temperature. In addition, experimental laboratory studies performed in different mechanical conditions on isolated samples of both ectosome and choanosome showed that temperature affects mesohyl mechanical properties: the lower is the temperature the stiffer is the mesohyl.The different physiological states recorded by the laboratory experiments are expressions of the mechanical adaptability of the collagenous mesohyl of C. reniformis and suggest that stiffness variability is under cellular control. On the basis of present results we can infer that C. reniformis can exert some control on the creeping phenomenon and that the primary factors implied in inducing creeping phenomena are the instability of substratum and the temperature.Interestingly the capability to modulate the mechanical properties of the collagenous matrix is an uncommon feature that C. reniformis shares with the mutable collagenous tissue (MCT) of Echinoderms. This close analogy, which is supported by morphological and physiological evidence, is an intriguing point that opens a wide range of evolutionary and functional questions.

Nonlinear tensile deformation behavior of small-sized metallic glasses

Unusual nonlinear deformation behavior with irreversible elongation has been observed in micrometer sized Co-based amorphous wires, and our analysis indicated that this nonlinear deformation is related to the formation of sub-nanometer voids coalesced from flow defects under the tensile stress. Amorphous wires with smaller diameters exhibit a lower apparent yield point, and the smaller shear transformation zone energy barriers associated with faster cooling rates applied during the fabrication process of these wires are responsible for their earlier apparent yielding and resultant elongation.

In situ observations of unusual drop deformation and wobbling in simple shear flow

Deformation and wobbling of a liquid drop immersed in a liquid matrix were studied under mild shear conditions for various viscosity ratios. In situ visualization experiments were conducted on a homemade transparent Couette cell incorporated to the Paar Physica MCR500 shear rheometer. The effect of drop or matrix elasticity was examined and was found to play a major role in both deformation and wobbling processes. Experimental results were compared to Jackson and Tucker (J Rheol 47:659–682, 2003), Maffettone and Minale (J Non-Newton Fluid Mech 78:227–241, 1998) and Yu and Bousmina (J Rheol 47:1011–1039, 2003) ellipsoidal models. It was found that the agreement between the Newtonian models and the experimental results required an increase in the drop viscosity. Such increment in viscosity was found to scale with the first normal stress difference.