Magnetic interactions in transition metal doped ZnO : An abinitio study

We calculate the nature of magnetic interactions in transition-metal doped ZnO using the local spin density approximation and LSDA+\textit{U} method of density functional theory. We investigate the following four cases: (i) single transition metal ion types (Cr, Mn, Fe, Co, Ni and Cu) substituted at Zn sites, (ii) substitutional magnetic transition metal ions combined with additional Cu and Li dopants, (iii) substitutional magnetic transition metal ions combined with oxygen vacancies and (iv) pairs of magnetic ion types (Co and Fe, Co and Mn, etc.). Extensive convergence tests indicate that the calculated magnetic ground state is unusually sensitive to the k-point mesh and energy cut-off, the details of the geometry optimizations and the choice of the exchange-correlation functional. We find that ferromagnetic coupling is sometimes favorable for single type substitutional transition metal ions within the local spin density approximation. However, the nature of magnetic interactions changes when correlations on the transition-metal ion are treated within the more realistic LSDA + \textit{U} method, often disfavoring the ferromagnetic state. The magnetic configuration is sensitive to the detailed arrangement of the ions and the amount of lattice relaxation, except in the case of oxygen vacancies when an antiferromagnetic state is always favored.Comment: 11 pages, 17 figure

THE EFFECTS OF DIET INDUCED OBESITY ON THE FORCE-LENGTH RELATIONSHIP IN RAT SOLEUS

INTRODUCTION Obesity is associated with chronic inflammation, which has been shown to affect the integrity of musculoskeletal tissues [1]. Previous data from our group suggests that obesity can result in intramuscular fat deposition [1]. It is unclear if this structural alteration has functional consequences, as the implications of obesity on muscle mechanics are not well understood. Therefore, the purpose of this study was to quantify the active force produced by soleus muscles of obese and non-obese rats at a range of muscle lengths. As the inclusion of fat into the muscle fibers will leave less room for contractile proteins, we hypothesized that obese rats will produce lower forces normalized to muscle mass at every length than non-obese control rats.   METHODS Fourteen rats were randomly allocated to a 12-week diet: either an obesity-inducing high fat high sucrose diet (DIO, 40% fat, 45% sucrose, n=8) or a standard chow diet (chow, 12% fat 0% sucrose, n=6). Prior to surgery, body composition was evaluated using dual energy X-ray absorptiometry. Custom-made tibial nerve cuffs were surgically attached to the right tibial nerve of each animal. The soleus was exposed, mechanically isolated, and clamped to a force transducer. The muscle was then stretched to a predetermined length and electrically stimulated at 3 times the motor unit threshold (50Hz) and the force output was measured [3]. Force tracings were digitized using WINDAQ® software. Passive, active, and total forces produced by the soleus were normalized to the maximum in vivo length of each animal. Forces were averaged into 5% length intervals within each animal. Students t-tests or a two-way ANOVA were conducted between groups, and a Bonferroni correction was used as needed, α=0.05. RESULTS DIO rats had increased body mass (DIO 816.4 ± 30.1g, chow 645.0 ± 28.3g; p<0.05) and body fat (DIO 39.2 ± 1.3%, chow 21.8 ± 2.1%; p<0.05) compared to chow-fed rats. Soleus mass (DIO: 0.28 ± 0.01 g, chow: 0.26 ± 0.11 g, p=0.32), was similar between the two groups. Absolute peak isometric force was similar between the two groups (DIO: 2.58 ± 0.10 N, chow: 2.18 ± 0.34 N, p=0.23). Active isometric force normalized to soleus mass was significantly higher in DIO group rats at every muscle length (Figure 1, p<0.05). DISCUSSION AND CONCLUSIONS On average, DIO rats produced more active force at a given normalized length and soleus mass than chow rats, a finding that refutes our original hypothesis. Since optimal length occurs at the same relative muscle length for both groups, and since the decline in force from maximum is similar between groups, it appears that fascicle length, and an associated shift in the force-length relationship cannot explain our results. Results of differences in the force-velocity relationship (not shown here) suggest that the DIO rats may have a higher proportion of fast twitch fibres, but the relative force among slow and fast fibres is similar, and thus also should not affect these results. The results suggest that the force per cross-sectional area is higher in muscles from obese compared to lean rats, a finding that defies explanation at this time and needs thorough investigation in the future. Histology and tests looking at fibre and cell level muscle structures may provide more insight

DIET INDUCED OBESITY MAY AFFECT THE FORCE-VELOCITY RELATIONSHIP IN RAT SOLEUS

INTRODUCTION Obesity is associated with chronic, low-grade inflammation that has been shown to affect several musculoskeletal tissues [1].  Previously, we observed that diet induced obesity (DIO) using a high-fat, high sugar diet results in molecular and morphological alterations in muscles, including an increase in intramuscular fat. However, it remains unclear if these alterations affect muscle function, as few studies have characterized the functional properties of muscles in obese individuals [2]. Arguably, one of the most important functional properties of skeletal muscle is the force-velocity relationship (FVR).  When muscles are shortening at increasing velocities, force decays exponentially as the proportion of attached cross bridges and the average force per cross-bridge decreases. As fat infiltration reduces the contractile material and structure of obese muscles, the functional properties of muscles, specifically the FVR may be affected. Therefore, the purpose of this study was to characterize the FVR in rat soleus muscles obtained from obese and normal rats. We hypothesized that soleus muscles of obese rats would produce lower absolute and relative forces at any given shortening velocity compared with muscles from control animals. METHODS Outbred, individually housed male Sprague-Dawley rats, aged 10-12 weeks, were randomized to a high fat, high sugar diet (DIO, 40% fat 45% sucrose, n=9) or a standard chow diet (n=5, chow, 12% fat, 0% sucrose) for 12 weeks. Prior to surgery, animals were sedated, weighed, and body composition was quantified using dual energy X-ray absorptiometry. The right soleus muscle was exposed and a custom cuff-type electrode was implanted on the tibial nerve. The soleus tendon was isolated from the Achilles with the calcaneus attached and fixed to a motor along the muscle’s natural alignment. The muscle was then stretched to its optimum length and electrically stimulated at 35Hz at 2.5x the motor unit threshold [3]. An isometric force reading was acquired over 2.5 s stimulation. The soleus was then stretched past its optimum length and shortened at increasing velocities, a force reading was collected at optimal length using Windaq Software. Data were collected at 1000Hz. Forces during shortening were measured at the same length and time point as the isometric reference force. This process was repeated for shortening velocities increasing from 2 mm/s to 70 mm/s. Animals were sacrificed and soleus muscles were harvested and weighed. Data were processed using a custom Matlab ® zero-phase filter program. Instantaneous forces were normalized to the peak isometric force for each animal. Comparisons were made using a Student’s t-tests, α=0.05. RESULTS On average, DIO animals had higher body mass and body fat compared to the control rats (p<0.001). Soleus mass was similar between DIO animals and chow (p=0.321), as was peak active isometric force (DIO: 2.48±0.10 N, chow: 2.08±0.33 p=0.183). FVR relationships were statistically different at shortening velocities between 3 and 35 mm/s (DIO > Chow at each given velocity; p<0.05, Fig. 1). DISCUSSION The results opposed the expected outcomes of this study and, therefore, the hypothesis was not satisfied. These findings could be due to a higher proportion of fast twitch fibers in the DIO or longer fascicle lengths in the DIO rats, but these speculations remain to be tested. Another possible explanation involves a potential increase in sensitivity to stimulation in the DIO soleus muscle resulting in increased force. Future work will examine other structural levels and muscle contractile proteins to understand these preliminary findings

Anterior cruciate ligament transection alters the n-3/n-6 fatty acid balance in the lapine infrapatellar fat pad

The infrapatellar fat pad (IFP) of the knee joint has received lots of attention recently due to its emerging role in the pathogenesis of osteoarthritis (OA), where it displays an inflammatory phenotype. The aim of the present study was to examine the infrapatellar fatty acid (FA) composition in a rabbit (Oryctolagus cuniculus) model of early OA created by anterior cruciate ligament transection (ACLT).Peer reviewe

The Eyes Have It: Sex and Sexual Orientation Differences in Pupil Dilation Patterns

Recent research suggests profound sex and sexual orientation differences in sexual response. These results, however, are based on measures of genital arousal, which have potential limitations such as volunteer bias and differential measures for the sexes. The present study introduces a measure less affected by these limitations. We assessed the pupil dilation of 325 men and women of various sexual orientations to male and female erotic stimuli. Results supported hypotheses. In general, self-reported sexual orientation corresponded with pupil dilation to men and women. Among men, substantial dilation to both sexes was most common in bisexual-identified men. In contrast, among women, substantial dilation to both sexes was most common in heterosexual-identified women. Possible reasons for these differences are discussed. Because the measure of pupil dilation is less invasive than previous measures of sexual response, it allows for studying diverse age and cultural populations, usually not included in sexuality research

Yielded to Christ or conformed to this world? Postwar Mennonite responses to labour activism

This is the accepted version of the manuscript.The urbanization of North American Mennonites after the Second World War necessitated a reconsideration of Mennonite religious beliefs. Post-war concerns for social justice led to a greater emphasis on non-violence and agape at the expense of Gelassenheit. The tenor of Mennonite church conference resolutions regarding labour union membership changed; while skepticism remained regarding the wisdom of union involvement, the door was left open for participation in unions. The labour militancy of the 1970s led Manitoba Mennonites to re-examine their engagement with the labour movement, a process that has continued to the present day. Without further research on Mennonite workplaces, it cannot be known exactly how the change in religious emphases has affected Mennonite identity.https://journals.sagepub.com/doi/abs/10.1177/00084298070360020

“It Was Easier in Prison!” : Russian Baptist Rehab as a Therapeutic Community, Monastery, Prison, and Ministry

This chapter revisits a Foucauldian concept of “complete and austere institutions,” using the ethnographic study of therapeutic communities, monasteries, prisons, and religious ministries to draw a line between those concepts, specifically addressing a Christian ministry in the Russian Baptist interpretation. My argument is based on an ethnographic account of the Russian Baptist ministry for people suffering from addiction. I unfold the concept of an Evangelical ministry, contrasting it to the Foucauldian austere institutions in order to highlight its nature. I argue that even though a rehabilitation ministry may use methods and techniques of austere institutions, and even resemble them in their implementation, the distinctive feature of a ministry is its focus on the result, rather than the process, interpreted as serving God by serving men.Peer reviewe

Medical student views of and responses to expectations of professionalism

Funding this study is part of the corresponding author's (EAS) doctoral programme of research funded by the University of Aberdeen, and supervised by EH and JC. Acknowledgements we thank all the students who took part in this project, and Professor Rona Patey, the Director of the Institute of Education for Medical and Dental Sciences, University of Aberdeen, for her support of this project.Peer reviewedPostprin