Interacting circular nanomagnets

Regular 2D rectangular lattices of permalloy nanoparticles (40 nm in diameter) were prepared by the method of the electron lithography. The magnetization curves were studied by Hall magnetometry with the compensation technique for different external field orientations at 4.2K and 77K. The shape of hysteresis curves indicates that there is magnetostatic interaction between the particles. The main peculiarity is the existence of remanent magnetization perpendicular to easy plain. By numerical simulation it is shown, that the character of the magnetization reversal is a result of the interplay of the interparticle interaction and the magnetization distribution within the particles (vortex or uniform).Comment: 16 pages, 8 figure

Assorted effects of TGFβ and chondroitinsulfate on p38 and ERK1/2 activation levels in human articular chondrocytes stimulated with LPS

SummaryObjectivesInadequate cellular response of chondrocytes to stress frequently terminates in osteoarthritis (OA). Adequate response is fundamentally modulated by concerted cytokine signaling events, directing degradation and synthesis of cartilage on articular surfaces where and whenever necessary. Transforming growth factor (TGF)β is a prominent mediator in cartilage anabolism, although particular catabolic activities are occasionally reported. Clearly, before the TGFβ signal gets through to the gene regulatory machinery, cross talk with modulators occurs.MethodWe tested the hypothesis whether chondroitinsulfate (CS) modulates cell signaling. TGFβ and/or soluble CS was added to human articular chondrocytes (HACs) and activation of p38 and extracellular signal related kinase (ERK)1/2 was determined by immunoblot analysis. Expression levels of mRNA of matrix metalloproteinase (MMP)-2, -3 and -13 were determined by real-time polymerase chain reaction (PCR).ResultsNo significant effects were observed unless cells were stimulated with lipopolysaccharide (LPS), invigorating catabolic metabolism in chondrocytes. LPS effects, however, were profoundly modulated by TGFβ, CS and both applied in combination. Most prominent, the silencing of p38 stress signal by CS was superimposable to that of TGFβ. Phospho-ERK1/2 levels were raised by TGFβ three-fold over LPS induced levels. In contrast, CS treatment, alone or combined with TGFβ, reduced phosphorylation significantly below LPS induced levels. Finally, suppression of LPS induced MMP-13 mRNA levels resulted with CS.ConclusionSoluble CS modulates signaling events in chondrocytes concurrent with MMP-13 down regulation. The effects observed suggest a feedback signaling mechanism cross talking with TGFβ-signal pathways and may serve an explanation, on the cellular level, for the beneficial effects found in clinical studies with pharmacologic application of CS

Dietary nitrate increases arginine availability and protects mitochondrial complex I and energetics in the hypoxic rat heart

This is the final version. It was first published by Wiley in The Journal of Physiology at http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2014.275263/abstract.Hypoxic exposure is associated with impaired cardiac energetics in humans and altered mitochondrial function, with suppressed complex I-supported respiration, in rat heart. This response might limit reactive oxygen species (ROS) generation, but at the cost of impaired electron transport chain (ETC) activity. Dietary nitrate supplementation improves mitochondrial efficiency and can promote tissue oxygenation by enhancing blood flow. We therefore hypothesised that ETC dysfunction, impaired energetics and oxidative damage in the hearts of rats exposed to chronic hypoxia could be alleviated by sustained administration of a moderate dose of dietary nitrate. Male Wistar rats (n=40) were given water supplemented with 0.7 mmol/L NaCl (as control) or 0.7 mmol/L NaNO3, elevating plasma nitrate levels by 80%, and were exposed to 13% O2 (hypoxia) or normoxia (n=10 per group) for 14 days. Respiration rates, ETC protein levels, mitochondrial density, ATP content and protein carbonylation were measured in cardiac muscle. Complex I respiration rates and protein levels were 33% lower in hypoxic/NaCl rats compared with normoxic/NaCl controls. Protein carbonylation was 65% higher in hearts of hypoxic rats compared with controls, indicating increased oxidative stress, whilst ATP levels were 62% lower. Respiration rates, complex I protein and activity, protein carbonylation and ATP levels were all fully protected in the hearts of nitrate-supplemented hypoxic rats. Both in normoxia and hypoxia, dietary nitrate suppressed cardiac arginase expression and activity and markedly elevated cardiac L-arginine concentrations, unmasking a novel mechanism of action by which nitrate enhances tissue NO bioavailability. Dietary nitrate therefore alleviates metabolic abnormalities in the hypoxic heart, improving myocardial energetics

Confidentiality and public protection: ethical dilemmas in qualitative research with adult male sex offenders

This paper considers the ethical tensions present when engaging in in-depth interviews with convicted sex offenders. Many of the issues described below are similar to those found in other sensitive areas of research. However, confidentiality and public protection are matters that require detailed consideration when the desire to know more about men who have committed serious and harmful offences is set against the possibility of a researcher not disclosing previously unknown sensitive information that relates to the risk of someone being harmed.</p

Tunneling Anisotropic Magnetoresistance in Co/AlOx/Au Tunnel Junctions

We observe spin-valve-like effects in nano-scaled thermally evaporated Co/AlOx/Au tunnel junctions. The tunneling magnetoresistance is anisotropic and depends on the relative orientation of the magnetization direction of the Co electrode with respect to the current direction. We attribute this effect to a two-step magnetization reversal and an anisotropic density of states resulting from spin-orbit interaction. The results of this study points to future applications of novel spintronics devices involving only one ferromagnetic layer.Comment: 11 pages, 5 figures. Accpted for publishing on Nano Letters, 200

How Coaching Philosophy Drives Coaching Action : A Case Study of Renowned Wrestling Coach J Robinson

This case study examined the coaching philosophy of J Robinson, one of the most respected and successful NCAA wrestling coaches in the United States, and the founder of J Robison Intensive Wrestling Camps. Research has that shown that his camps foster short and long term psychological development in its youth participants (Driska et al., in press; Pierce, et al., 2016). He has established a well-delineated system for developing psychological skills in young athletes. The researchers were therefore interested in understanding the link between his coaching philosophy and coaching behavior, and in identifying factors that have influenced the development of this coaching philosophy over his lifetime. Using a case study approach, in-depth interviews at several points in time with Robinson were conducted. These were supplemented with interviews with camp staff and observations of the camp and Robinson’s coaching. Results revealed that Robinson had a clearly defined philosophy, was very intentional in developing mental skills, and had clearly thought out rationales that guided his coaching actions. The coaching philosophy and approach to developing psychological skills in youth evolved over 35 years of implementing these camps and from Robinson’s own life experiences. Implications for studying coach development and delivering coaching education are provided

Ultralong Copper Phthalocyanine Nanowires with New Crystal Structure and Broad Optical Absorption

The development of molecular nanostructures plays a major role in emerging organic electronic applications, as it leads to improved performance and is compatible with our increasing need for miniaturisation. In particular, nanowires have been obtained from solution or vapour phase and have displayed high conductivity, or large interfacial areas in solar cells. In all cases however, the crystal structure remains as in films or bulk, and the exploitation of wires requires extensive post-growth manipulation as their orientations are random. Here we report copper phthalocyanine (CuPc) nanowires with diameters of 10-100 nm, high directionality and unprecedented aspect ratios. We demonstrate that they adopt a new crystal phase, designated eta-CuPc, where the molecules stack along the long axis. The resulting high electronic overlap along the centimetre length stacks achieved in our wires mediates antiferromagnetic couplings and broadens the optical absorption spectrum. The ability to fabricate ultralong, flexible metal phthalocyanine nanowires opens new possibilities for applications of these simple molecules

Endothelial cell regulation of systemic haemodynamics and metabolism acts through the HIF transcription factors.

BackgroundThe vascular endothelium has important endocrine and paracrine roles, particularly in the regulation of vascular tone and immune function, and it has been implicated in the pathophysiology of a range of cardiovascular and inflammatory conditions. This study uses a series of transgenic murine models to explore for the first time the role of the hypoxia-inducible factors, HIF-1α and HIF-2α in the pulmonary and systemic circulations as potential regulators of systemic vascular function in normoxic or hypoxic conditions and in response to inflammatory stress. We developed a series of transgenic mouse models, the HIF-1α Tie2Cre, deficient in HIF1-α in the systemic and pulmonary vascular endothelium and the L1Cre, a pulmonary endothelium specific knockout of HIF-1α or HIF-2α. In vivo, arterial blood pressure and metabolic activity were monitored continuously in normal atmospheric conditions and following an acute stimulus with hypoxia (10%) or lipopolysaccharide (LPS). Ex vivo, femoral artery reactivity was assessed using wire myography.ResultsUnder normoxia, the HIF-1α Tie2Cre mouse had increased systolic and diastolic arterial pressure compared to litter mate controls over the day-night cycle under normal environmental conditions. VO2 and VCO2 were also increased. Femoral arteries displayed impaired endothelial relaxation in response to acetylcholine mediated by a reduction in the nitric oxide dependent portion of the response. HIF-1α L1Cre mice displayed a similar pattern of increased systemic blood pressure, metabolic rate and impaired vascular relaxation without features of pulmonary hypertension, polycythaemia or renal dysfunction under normal conditions. In response to acute hypoxia, deficiency of HIF-1α was associated with faster resolution of hypoxia-induced haemodynamic and metabolic compromise. In addition, systemic haemodynamics were less compromised by LPS treatment.ConclusionsThese data show that deficiency of HIF-1α in the systemic or pulmonary endothelium is associated with increased systemic blood pressure and metabolic rate, a pattern that persists in both normoxic conditions and in response to acute stress with potential implications for our understanding of the pathophysiology of vascular dysfunction in acute and chronic disease