Domain wall fermions for planar physics

In 2+1 dimensions, Dirac fermions in reducible, i.e. four-component representations of the spinor algebra form the basis of many interesting model field theories and effective descriptions of condensed matter phenomena. This paper explores lattice formulations which preserve the global U(2N) symmetry present in the massless limit, and its breakdown to U(N)xU(N) implemented by three independent and parity-invariant fermion mass terms. I set out generalisations of the Ginsparg-Wilson relation, leading to a formulation of an overlap operator, and explore the remnants of the global symmetries which depart from the continuum form by terms of order of the lattice spacing. I also define a domain wall formulation in 2+1+1d, and present numerical evidence, in the form of bilinear condensate and meson correlator calculations in quenched non-compact QED using reformulations of all three mass terms, to show that U(2N) symmetry is recovered in the limit that the domain-wall separation L tends to infinity. The possibility that overlap and domain wall formulations of reducible fermions may coincide only in the continuum limit is discussed

Iron Accumulation with Age, Oxidative Stress and Functional Decline

Identification of biological mediators in sarcopenia is pertinent to the development of targeted interventions to alleviate this condition. Iron is recognized as a potent pro-oxidant and a catalyst for the formation of reactive oxygen species in biological systems. It is well accepted that iron accumulates with senescence in several organs, but little is known about iron accumulation in muscle and how it may affect muscle function. In addition, it is unclear if interventions which reduced age-related loss of muscle quality, such as calorie restriction, impact iron accumulation. We investigated non-heme iron concentration, oxidative stress to nucleic acids in gastrocnemius muscle and key indices of sarcopenia (muscle mass and grip strength) in male Fischer 344 X Brown Norway rats fed ad libitum (AL) or a calorie restricted diet (60% of ad libitum food intake starting at 4 months of age) at 8, 18, 29 and 37 months of age. Total non-heme iron levels in the gastrocnemius muscle of AL rats increased progressively with age. Between 29 and 37 months of age, the non-heme iron concentration increased by approximately 200% in AL-fed rats. Most importantly, the levels of oxidized RNA in gastrocnemius muscle of AL rats were significantly increased as well. The striking age-associated increase in non-heme iron and oxidized RNA levels and decrease in sarcopenia indices were all attenuated in the calorie restriction (CR) rats. These findings strongly suggest that the age-related iron accumulation in muscle contributes to increased oxidative damage and sarcopenia, and that CR effectively attenuates these negative effects

Identifying a Window of Vulnerability during Fetal Development in a Maternal Iron Restriction Model

It is well acknowledged from observations in humans that iron deficiency during pregnancy can be associated with a number of developmental problems in the newborn and developing child. Due to the obvious limitations of human studies, the stage during gestation at which maternal iron deficiency causes an apparent impairment in the offspring remains elusive. In order to begin to understand the time window(s) during pregnancy that is/are especially susceptible to suboptimal iron levels, which may result in negative effects on the development of the fetus, we developed a rat model in which we were able to manipulate and monitor the dietary iron intake during specific stages of pregnancy and analyzed the developing fetuses. We established four different dietary-feeding protocols that were designed to render the fetuses iron deficient at different gestational stages. Based on a functional analysis that employed Auditory Brainstem Response measurements, we found that maternal iron restriction initiated prior to conception and during the first trimester were associated with profound changes in the developing fetus compared to iron restriction initiated later in pregnancy. We also showed that the presence of iron deficiency anemia, low body weight, and changes in core body temperature were not defining factors in the establishment of neural impairment in the rodent offspring

Integrating lifestyle approaches into osteoarthritis care

Matthew J Garver,1 Brian C Focht,2 Sarah J Taylor3 1Department of Kinesiology and Nutrition, Abilene Christian University, Abilene, TX, 2Department of Human Sciences, Ohio State University, Columbus, OH, 3School of Occupational Therapy, Texas Woman's University, Dallas, TX, USA Abstract: As the lifetime risk, societal cost, and overall functional impact of osteoarthritis (OA) is imposing, it is imperative that clinicians provide an individualized care model for patients. Patients must be offered a multiplicity of care strategies and encouraged to embrace lifestyle approaches for self-managing the effects and symptoms of OA. Certainly, the attitude of the clinician and patient will directly influence receptivity and implementation of lifestyle approaches. This work proposes how the use of structured and routine assessments and cognitive therapy ideologies may complement a comprehensive treatment plan. Assessments described herein include objective and/or self-report measures of physical function, pain, attitude about social support, and sleep quality. Baseline assessments followed by systematic monitoring of the results may give patients and clinicians valuable insight into the effectiveness of the care plan. Empirical evidence from randomized trials with OA patients highlights the effectiveness of cognitive behavioral change strategies for addressing salient concerns for OA (pain control, mobility performance, and sleep quality). Cognitive restructuring can provide patients with renewed power in managing their disease. Cognitive therapy topics discussed presently include: 1) what is OA?, 2) effectiveness of exercise and FITT (frequency, intensity, time, and type) principles for OA patients, 3) goal-setting and barriers, and 4) translating to independent care. Woven within the discussion about cognitive therapy are ideas about how the results from baseline assessments and group-mediated dynamics might assist more favorable outcomes. There are a plethora of assessments and cognitive therapy topics that could be utilized in the care strategy that we are promoting, but the present topics were selected for their low clinician and patient burden and promising results in trials with OA patients. Clinicians who are comfortable and knowledgeable about a wider range of management tools may serve more effectively in the critical, central management process and help patients embrace personal care more successfully. Keywords: osteoarthritis, lifestyle approaches, assessments, cognitive behavioral therap