Thermal and elastic properties of Cu–Zr–Be bulk metallic glass forming alloys

The compositional dependence of thermal and elastic properties of Cu–Zr–Be ternary bulk metallic glass forming alloys was systematically studied. There exists a linear relationship between the glass transition temperature Tg and the total Zr concentration. G decreases linearly with increasing Zr concentration as well. The results also show that Tg, shear modulus G, and Poisson's ratio nu are very sensitive to changes in compositions. Low Tg, low G, and relatively high nu can be achieved with high Zr and Ti concentration

Critical and Liberative Theories: Applications in Engineering Education

Background. Higher educational programs in engineering today are seeking to correct disproportionately low enrollment and success rates of minoritized students. However, most diversity-related programming fails to address systems of structural oppression that cause particular students to be underrepresented in higher education. In addition, typical engineering pedagogical methods fail to address the reality and impacts of structural oppression, as educators cannot overcome the effects of structurally oppressive systems through traditional methods of controlling classroom and curriculum.Purpose. This paper explores the relationship between existing critical and liberative theories and engineering educational systems and re-frames the goals and problems of diversity and equity within engineering education from a critical and liberative lens.Methodology/Approach. We describe existing liberative pedagogies and their aim to dismantle oppressive systems through recognition of hegemonic structures, critical classroom discourse, and opportunities to build solidarity. We present an overview of previous uses of these pedagogies in engineering classrooms under the premise of Freirean critical theory, which is class-based, and other anti-oppressive theories based on race, gender, and sexual orientation. We propose a new model that situates these theories relative to one another within the broader classification of identity-based theories.Conclusions. Class-based exploitation under capitalist economic and governmental structures is identified as the root cause of inequitable educational outcomes. Thus, in order to correct inequities in education, the role of current educational systems in the perpetuation of capitalist oppression must itself be addressed. This will require pedagogical changes as well as explicitly restructuring the goals of engineering education to include equity and solidarity.Implications. Through an embrace of critical and liberative theories and their accompanying pedagogies, engineering educators and engineering education researchers can plant the seeds for change. When engineers develop the skills necessary to recognize and combat oppression, they will be able to work toward liberation for all oppressed peoples

Acute hemorrhagic demyelination in a murine model of multiple sclerosis

Acute hemorrhagic leukoencephalomyelitis (AHLE) is a rare neurological condition characterized by the development of acute hemorrhagic demyelination and high mortality. The pathomechanism of AHLE, as well as potential therapeutic approaches, have remained elusive due to the lack of suitable animal models. We report the first murine model of AHLE using a variation of the Theiler's Murine Encephalitis Virus (TMEV) MS model. During acute TMEV infection, C57BL/6 mice do not normally undergo demyelination. However, when 7 day TMEV infected C57BL/6 mice are intravenously administered the immunodominant CD8 T cell peptide, VP2121–130, animals develop characteristics of human AHLE based on pathologic, MRI and clinical features including microhemorrhages, increased blood-brain barrier permeability, and demyelination. The animals also develop severe disability as assessed using the rotarod assay. This study demonstrates the development of hemorrhagic demyelination in TMEV infected C57BL/6 mice within 24 hours of inducing this condition through intravenous administration of CD8 T cell restricted peptide. This study is also the first demonstration of rapid demyelination in a TMEV resistant non-demyelinating strain without transgenic alterations or pharmacologically induced immunosuppression

Functional Comparison of Six-Minute Walk Tests Between Shod and Minimalist Footwear Individuals in Mid-Life: A Preliminary Pilot Study Analysis

Research has shown that wearing minimalistic footwear can increase intrinsic and extrinsic foot muscle size and strength,although the effect of transitioning from shod to minimalist footwear on gait functionality–such as performance on a six-minute walk test–is not well documented. PURPOSE: We observed the differences in a six-minute functional walk test between mid-life (45yrs-65yrs) individuals who transitioned to minimalist footwear (MF) over a fourteen month period compared to habitually shod (HS) individuals. METHODS: Twenty mid-life individuals participated in this study. Participants were randomly assigned to either the MF (n=8, age= 56.5 ± 5.18 yrs, height= 162.71 ± 7.69 cm, weight= 82.71 ± 16.24 kg,) or HS (n=12, age= 57.36 ± 5.43 yrs, height= 162.91 ± 7.44 cm, weight= 73.48 ± 15.65 kg) group. MF participants were coached through a nine-week training to safely transition to MF. Participants assigned to the HS group were instructed to continue normal activity. Each participant underwent a data collection at 1 week, 9 weeks, 8 months, and 14 months. At each data collection, the individual was instructed to walk as far as possible around a set track for 6 minutes. Every lap around the track was 208 feet and partial laps were measured to the distance completed. RESULTS: A repeated measures ANOVA indicated a significant increase in distance walked at 8 months (1703.5 ± 190.2 ft, p=0.009) and 14 months (1708.1 ± 181.1 ft, p=0.025) compared to week 1 (1634.6 ± 194.7 ft). There was no significant difference between groups in the increase in walking distance (p=0.950). Significant covariates were biological sex (p=0.007) and height (p=0.034). CONCLUSION: Overall, participants in the study increased walking distance in the six-minute walk test regardless of group. Therefore, minimalist shoes do not appear to affect gait functionality in mid-life adults during the six-minute walk test

Pathway interactions between MAPKs, mTOR, PKA, and the glucocorticoid receptor in lymphoid cells

BACKGROUND: Glucocorticoids are frequently used as a primary chemotherapeutic agent in many types of human lymphoid malignancies because they induce apoptosis through activation of the glucocorticoid receptor, with subsequent alteration of a complex network of cellular mechanisms. Despite clinical usage for over fifty years, the complete mechanism responsible for glucocorticoid-related apoptosis or resistance remains elusive. The mitogen-activated protein kinase pathway is a signal transduction network that influences a variety of cellular responses through phosphorylation of specific target substrates, including the glucocorticoid receptor. In this study we have evaluated the pharmaceutical scenarios which converge on the mitogen-activated protein kinase pathway to alter glucocorticoid sensitivity in clones of human acute lymphoblastic CEM cells sensitive and refractory to apoptosis in response to the synthetic glucocorticoid dexamethasone. RESULTS: The glucocorticoid-resistant clone CEM-C1-15 displays a combination of high constitutive JNK activity and dexamethasone-induced ERK activity with a weak induction of p38 upon glucocorticoid treatment. The cells become sensitive to glucocorticoid-evoked apoptosis after: (1) inhibition of JNK and ERK activity, (2) stimulation of the cAMP/PKA pathway with forskolin, or (3) inhibition of mTOR with rapamycin. Treatments 1–3 in combination with dexamethasone alter the intracellular balance of phospho-MAPKs by lowering JNK phosphorylation and increasing the level of glucocorticoid receptor phosphorylated at serine 211, a modification known to enhance receptor activity. CONCLUSION: Our data support the hypothesis that mitogen-activated protein kinases influence the ability of certain malignant lymphoid cells to undergo apoptosis when treated with glucocorticoid. Activated/phosphorylated JNK and ERK appear to counteract corticoid-dependent apoptosis. Inhibiting these MAPKs restores corticoid sensitivity to a resistant clone of CEM cells. Forskolin, which activates the cAMP pathway, and rapamycin, which inhibits mTOR, also inhibit JNK. Further, the sensitizing treatments result in a largely dexamethasone-dependent increase in the total pool of glucocorticoid receptor phosphorylated at serine 211. The phospho-serine 211 receptor is known to be more potent in activating gene transcription and apoptosis. The interactive effects demonstrated here in reverting resistant cells to corticoid sensitivity could provide therapeutic clinical potential in the treatment of lymphoid malignancies

Vascular Alteration with Postural Change as Observed Using the Anterior Tibial Artery: A Pilot Study

Plantar fasciopathy and plantar fasciosis are common lower extremity conditions. Vascular health is an important aspect of plantar fascia health. Footwear choices are thought to influence lower extremity vascular flow, but how the anterior tibial artery is affected by purely postural changes over time is unknown. PURPOSE: To observe the anterior tibial artery vascular alterations over a ten-minute period after transitioning from a sitting to a standing position while barefoot. METHODS: Nine participants (age= 23.8yrs ±2.5, height= 176.0cm ±8.0, weight= 69.8kg ±10.2) were recruited from Brigham Young University for a single 30-minute visit. The participants had no previous lower extremity injuries within 6 months. The individual’s dominant foot arch height index was recorded, and the participant had a 3-lead ECG placed on their trunk. A Logic Fortis machine with an L8-18i probe was used to capture pulse wave (PW) images of the anterior tibial artery of the dominant foot. The participant sat barefoot on an elevated platform for five minutes and baseline PW was recorded. The participant then stood on the platform for 11 total minutes. PW images were captured once at the end of every minute for the first five minutes and a final PW measurement was captured after ten minutes of standing. A paired t-test was used to compare standing time points to baseline (α=0.05). RESULTS: After standing, time-averaged mean velocity (TAMean) significantly dropped through minutes one (pCONCLUSION: Blood flow through the anterior tibial artery is significantly altered with postural changes likely through cardiovascular responses. Vascular recovery is observed after three minutes while the average increase in vascular response occurs around ten minutes

Anatomic Femoral and Tibial Tunnel Placement During Anterior Cruciate Ligament Reconstruction: Anteromedial Portal All-Inside and Outside-In Techniques

Tunnel malposition is one of the most common technical reasons for anterior cruciate ligament reconstruction failure. Small changes in tunnel placement can result in significant differences in outcome. More anatomic placement of the tunnels can lead to greater knee stability and a more accurate reproduction of native knee kinematics. This Technical Note describes 2 tibial tunnel–independent methods to obtain anatomic femoral tunnel placement. The all-inside anteromedial portal technique requires only minimal surgical incisions but allows precise femoral tunnel placement. However, hyperflexion of the knee is required, adequate surgical assistance is necessary, and this technique may be susceptible to graft-tunnel mismatch. The outside-in technique may be more beneficial in obese patients, skeletally immature patients, or revision cases. On the downside, it does require an additional 2-cm surgical incision. This article also provides surgical pearls to fine-tune tibial tunnel placement