Skeletal muscle dysfunction is associated with derangements in mitochondrial bioenergetics (but not UCP3) in a rodent model of sepsis

Muscle dysfunction is a common feature of severe sepsis and multi-organ failure. Recent evidence implicates bioenergetic dysfunction and oxidative damage as important underlying pathophysiological mechanisms. Increased abundance of uncoupling protein-3 (UCP-3) in sepsis suggests increased mitochondrial proton leak, which may reduce mitochondrial coupling efficiency but limit ROS production. Using a murine model, we examined metabolic, cardiovascular and skeletal muscle contractile changes following induction of peritoneal sepsis in wild-type and Ucp3(-/-) mice. Mitochondrial membrane potential (Δψm) was measured using two-photon microscopy in living diaphragm, and contractile function was measured in diaphragm muscle strips. The kinetic relationship between membrane potential and oxygen consumption was determined using a modular kinetic approach in isolated mitochondria. Sepsis was associated with significant whole body metabolic suppression, hypothermia and cardiovascular dysfunction. Maximal force generation was reduced and fatigue accelerated in ex vivo diaphragm muscle strips from septic mice. Mitochondrial membrane potential was lower in the isolated diaphragm from septic mice despite normal substrate oxidation kinetics and proton leak in skeletal muscle mitochondria. Even though wild-type mice exhibited an absolute 26 ± 6% higher UCP-3 protein abundance at 24 hours, no differences were seen in whole animal or diaphragm physiology, nor in survival rates, between wild-type and Ucp3(-/-) mice. In conclusion, this murine sepsis model shows a hypometabolic phenotype with evidence of significant cardiovascular and muscle dysfunction. This was associated with lower Δψm and alterations in mitochondrial ATP turnover and phosphorylation pathway. However, UCP-3 does not play an important functional role, despite its upregulation

Sweet taste exposure and the subsequent acceptance and preference for sweet taste in the diet : systematic review of the published literature

Background: There are consistent, evidence-based global public health recommendations to reduce intakes of free sugars. However, the corresponding evidence for recommending reduced exposure to sweetness is less clear. Objective: Our aim was to identify and review the published evidence investigating the impact of dietary exposure to sweet-tasting foods or beverages on the subsequent generalized acceptance, preference, or choice of sweet foods and beverages in the diet. Design: Systematic searches were conducted to identify all studies testing relations of variation in exposure to sweetness through foods and beverages with subsequent variation in the generalized acceptance, preference, or choice of sweetened foods or beverages, in humans aged >6 mo. Results: Twenty-one studies met our inclusion criteria, comprising 7 population cohort studies involving 2320 children and 14 controlled trials involving 1113 individuals. These studies were heterogeneous in study design, population, exposure, and outcomes measured, and few were explicitly designed to address our research question. The findings from these were inconsistent. We found equivocal evidence from population cohort studies. The evidence from controlled studies suggests that a higher sweet taste exposure tends to lead to reduced preferences for sweetness in the shorter term, but very limited effects were found in the longer term. Conclusions: A small and heterogeneous body of research currently has considered the impact of varying exposure to sweet taste on subsequent generalized sweet taste preferences, and this evidence is equivocal regarding the presence and possible direction of a relation. Future work should focus on adequately powered studies with well-characterized exposures of sufficient duration.Peer reviewe

Laboratory Experiment on the Effect of Carbibe Waste and Metakaolin on Strength and Durability Properties of Blended Concrete

The versatility of concrete makes it the most desirable construction material in the construction industry. The increase in global population growth and urbanization leads to a high demand for more basic infrastructure. The high cost of concrete structures is largely influenced by cost of the constituent materials and it is an important constituent in the making of concrete There are other cementing materials which have shown the ability to improve the properties of concrete and also presents both environmental sustainability and economic benefits. For this study investigation into the suitability of using calcium carbide waste and metakaolin in concrete production, this investigation involves the replacement of cement with blend of calcium carbide waste and metakaolin in an increment of 0, 5, 10, 15 and 20%. Concrete cube containing CCW-MK was tested for strength at 3, 7, 14, 28 and 56 days of curing age. The optimum compressive strength was recorded at 10% CCW-MK content. 5% concentration of H2SO4 was used to cure the concrete for 28 days. Oxide composition test was done on the CCW and MK. The results revealed that CCW had a CaO content of 86.43% and MK had a sum of Al2O3, SiO2 and Fe2O3 as 98.6%. The workability of CCW-MK increases with increase as the dosage of CCW-MK increase. The compressive strength of CCW-MK concrete increased with an increase in the dosage of CCW-MK and curing period respectively. The retained compressive strength of CCWMK concrete cured in H2SO4 with an increase in the dosage of CCW-MK. Furthermore, the water absorption increases with an increase in the dosage of CCW-MK. Microstructural analysis of CCW-MK concrete was done with the aid scanning electron microscope equipment. The microstructure of the maximum compressive strength sample shows a denser, more homogenous and compact hardened concrete with respect to the control. It was concluded that blended concrete with sufficient strength can be achieved with the addition of CCW and MK blends can as supplementary cementing materials in concrete production

Experimental behaviour of stainless steel cellular beam in fire

This paper appeared in a special Issue: Proceedings of Nordic Steel 201

Fracture simulation of welded RHS X-joints using GTN damage model

publishedVersionPeer reviewe

A rapid controller of temperature for use in determining Arrhenius profiles in biomembrane systems

To minimize artifacts in temperature-velocity (Arrhenius) profiles due to aging of preparations of biological membranes, a rapid controller of temperature was developed for spectrophotometric or polarographic (O 2 electrode) measurements. The reaction mixture is cooled or heated through contact with Peltier elements. One Pt temperature sensor in the cuvette or electrode holder controls current flow into the Peltier units, and another Pt temperature sensor in the reaction mixture is used to read out the sample temperature on a meter or recorder, and to provide feedback control. The sample temperature can be reproducibly set to within 0.1°C, with a noise level of 0.04°C or less; a change of 4°C takes 1 min.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44794/1/10863_2004_Article_BF00744744.pd

The Mitochondrial Ca(2+) Uniporter: Structure, Function, and Pharmacology.

Mitochondrial Ca(2+) uptake is crucial for an array of cellular functions while an imbalance can elicit cell death. In this chapter, we briefly reviewed the various modes of mitochondrial Ca(2+) uptake and our current understanding of mitochondrial Ca(2+) homeostasis in regards to cell physiology and pathophysiology. Further, this chapter focuses on the molecular identities, intracellular regulators as well as the pharmacology of mitochondrial Ca(2+) uniporter complex