Type 2 diabetes and reduced exercise tolerance: A review of the literature through an integrated physiology approach

The association between type 2 diabetes mellitus (T2DM) and heart failure (HF) is well established. Early in the course of the diabetic disease, some degree of impaired exercise capacity (a powerful marker of health status with prognostic value) can be frequently highlighted in otherwise asymptomatic T2DM subjects. However, the literature is quite heterogeneous, and the underlying pathophysiologic mechanisms are far from clear. Imaging-cardiopulmonary exercise testing (CPET) is a non-invasive, provocative test providing a multi-variable assessment of pulmonary, cardiovascular, muscular, and cellular oxidative systems during exercise, capable of offering unique integrated pathophysiological information. With this review we aimed at defying the cardiorespiratory alterations revealed through imaging-CPET that appear specific of T2DM subjects without overt cardiovascular or pulmonary disease. In synthesis, there is compelling evidence indicating a reduction of peak workload, peak oxygen assumption, oxygen pulse, as well as ventilatory efficiency. On the contrary, evidence remains inconclusive about reduced peripheral oxygen extraction, impaired heart rate adjustment, and lower anaerobic threshold, compared to non-diabetic subjects. Based on the multiparametric evaluation provided by imaging-CPET, a dissection and a hierarchy of the underlying mechanisms can be obtained. Here we propose four possible integrated pathophysiological mechanisms, namely myocardiogenic, myogenic, vasculogenic and neurogenic. While each hypothesis alone can potentially explain the majority of the CPET alterations observed, seemingly different combinations exist in any given subject. Finally, a discussion on the effects -and on the physiological mechanisms-of physical activity and exercise training on oxygen uptake in T2DM subjects is also offered. The understanding of the early alterations in the cardiopulmonary response that are specific of T2DM would allow the early identification of those at a higher risk of developing HF and possibly help to understand the pathophysiological link between T2DM and HF

Spin/orbit moment imbalance in the near-zero moment ferromagnetic semiconductor SmN

SmN is ferromagnetic below 27 K, and its net magnetic moment of 0.03 Bohr magnetons per formula unit is one of the smallest magnetisations found in any ferromagnetic material. The near-zero moment is a result of the nearly equal and opposing spin and orbital moments in the 6H5/2 ground state of the Sm3+ ion, which leads finally to a nearly complete cancellation for an ion in the SmN ferromagnetic state. Here we explore the spin alignment in this compound with X-ray magnetic circular dichroism at the Sm L2,3 edges. The spectral shapes are in qualitative agreement with computed spectra based on an LSDA+U (local spin density approximation with Hubbard-U corrections) band structure, though there remain differences in detail which we associate with the anomalous branching ratio in rare-earth L edges. The sign of the spectra determine that in a magnetic field the Sm 4f spin moment aligns antiparallel to the field; the very small residual moment in ferromagnetic SmN aligns with the 4f orbital moment and antiparallel to the spin moment. Further measurements on very thin (1.5 nm) SmN layers embedded in GdN show the opposite alignment due to a strong Gd-Sm exchange, suggesting that the SmN moment might be further reduced by about 0.5 % Gd substitution

Water-Assisted Concerted Proton-Electron Transfer at Co(II)-Aquo Sites in Polyoxotungstates With Photogenerated RuIII(bpy)33+ Oxidant

The cobalt substituted polyoxotungstate [Co6(H2O)2(α-B-PW9O34)2(PW6O26)]17− (Co6) displays fast electron transfer (ET) kinetics to photogenerated RuIII(bpy)33+, 4 to 5 orders of magnitude faster than the corresponding ET observed for cobalt oxide nanoparticles. Mechanistic evidence has been acquired indicating that: (i) the one-electron oxidation of Co6 involves Co(II) aquo or Co(II) hydroxo groups (abbreviated as Co6(II)−OH2 and Co6(II)−OH, respectively, whose speciation in aqueous solution is associated to a pKa of 7.6), and generates a Co(III)−OH moiety (Co6(III)−OH), as proven by transient absorption spectroscopy; (ii) at pH>pKa, the Co6(II)−OH→RuIII(bpy)33+ ET occurs via bimolecular kinetics, with a rate constant k close to the diffusion limit and dependent on the ionic strength of the medium, consistent with reaction between charged species; (iii) at p

Elusive enemies: consumptive and ovipositional effects on mosquitoes by predatory midge larvae are enhanced in dyed environments

Mosquito-borne disease incidences continue to proliferate and cause enormous mortality and debilitation rates. Predatory natural enemies can be effective in population management strategies targeting medically-important mosquito species. However, context-dependencies and target organism behavioural responses can impede or facilitate biological control agents. Black pond dye has been shown to be a strong mosquito oviposition attractant, and could potentially be used alongside predatory agents to create mosquito population sink effects. Here, we thus examine the predatory impact of larvae of the non-biting chaoborid midge Chaoborus flavicans towards larvae of the West Nile virus vector mosquito complex Culex pipiens in the presence and absence of black pond dye. We then examine the ovipositional responses of C. pipiens to predation risk and dye in laboratory-, semi-field- and field-based trials. Larval C. flavicans exhibited potentially population destabilising type II functional responses towards mosquito larvae irrespective of the presence of pond dye. Neither consumption rates nor functional response parameters (attack rates, handling times) were significantly influenced by the presence of dye, indicating a use of hydromechanics to detect mosquito prey by chaoborids. Wild-caught adult C. pipiens did not avoid predatory chaoborids when ovipositing, however they were significantly more attracted to oviposit in dye-treated water regardless of the presence of predators. We thus demonstrate high predatory impact towards mosquito larvae by non-biting chaoborid midges during their predaceous aquatic larval stages, and proliferations of such predators may assist or augment control efforts for mosquitoes. Our results suggest a lack of influence of predatory dipterans on oviposition selectivity by C. pipiens mosquitoes, and that pond dye may enhance the efficacy of select predatory biological control agents through the creation of population sinks, characterised by high rates of oviposition and subsequent predation

Magnetic Surgical Instruments for Robotic Abdominal Surgery.

This review looks at the implementation of magnetic-based approaches in surgical instruments for abdominal surgeries. As abdominal surgical techniques advance toward minimizing surgical trauma, surgical instruments are enhanced to support such an objective through the exploration of magnetic-based systems. With this design approach, surgical devices are given the capabilities to be fully inserted intraabdominally to achieve access to all abdominal quadrants, without the conventional rigid link connection with the external unit. The variety of intraabdominal surgical devices are anchored, guided, and actuated by external units, with power and torque transmitted across the abdominal wall through magnetic linkage. This addresses many constraints encountered by conventional laparoscopic tools, such as loss of triangulation, fulcrum effect, and loss/lack of dexterity for surgical tasks. Design requirements of clinical considerations to aid the successful development of magnetic surgical instruments, are also discussed

A methodological approach of QRA for slow-moving landslides at a regional scale

Landslides represent a serious worldwide hazard, especially in Italy, where exposure to hydrogeological risk is very high; for this reason, a landslide quantitative risk assessment (QRA) is crucial for risk management and for planning mitigation measures. In this study, we present and describe a novel methodological approach of QRA for slow-moving landslides, aiming at national replicability. This procedure has been applied at the basin scale in the Arno River basin (9100 km(2), Central Italy), where most landslides are slow-moving. QRA is based on the application of the equation risk = hazard (H) × vulnerability (V) × exposure (E) and on the use of open data with uniform characteristics at the national scale. The study area was divided into a grid with a 1 km(2) cell size, and for each cell, the parameters necessary for the risk assessment were calculated. The obtained results show that the total risk of the study area amounts to approximately 7 billion €. The proposed methodology presents several novelties in the risk assessment for the regional/national scale of the analysis, mainly concerning the identification of the datasets and the development of new methodologies that could be applicable over such large areas. The present work demonstrates the feasibility of the methodology and discusses the obtained results