265 research outputs found
Scientific Developments Connected with the Second Industrial Revolution: A. Baracca, S. Ruffo, and A. Russo, Scienza e Industria 1848â1915, 41 years later
The pioneering work, Scienza e Industria 1848â1915: Gli sviluppi scientifici connessi alla seconda rivoluzione industriale (Science and Industry 1848â1915: Scientific developments related to the second industrial revolution) by Angelo Baracca, Stefano Ruffo, and Arturo Russo is reproduced in this preprint. Published in Italian by Laterza in 1979, it is an unjustly forgotten treasure of a highly fertile and innovative period of the history of science. The introduction to the preprint describes the historical circumstances in which this book and the approach it proposes emerged. It covers a wide range of subjects, from the different ways in which the Second Industrial Revolution unfolded in Great Britain and in continental Europe to the upheaval in modern science, in particular in chemistry in the latter half of the nineteenth century and in physics at the beginning of the twentieth century. Although each of these themes has meanwhile become the subject of detailed historical investigations, the survey and overall picture that Scienza e Industria provides is still intriguing: it connects the new knowledge economy of the Second Industrial Revolution with the conceptual revolutions in modern physics by pointing to the mediatory role of chemistry
Is supercomplex organization of the respiratory chain required for optimal electron transfer activity?
AbstractThe supra-molecular assembly of the main respiratory chain enzymatic complexes in the form of âsupercomplexesâ has been proved by structural and functional experimental evidence. This evidence strongly contrasts the previously accepted Random Diffusion Model stating that the complexes are functionally connected by lateral diffusion of small redox molecules (i.e. Coenzyme Q and cytochrome c).This review critically examines the available evidence and provides an analysis of the functional consequences of the intermolecular association of the respiratory complexes pointing out the role of Coenzyme Q and of cytochrome c as channeled or as freely diffusing intermediates in the electron transfer activity of their partner enzymes
Long-Term Oral Administration of Theaphenon-E Improves Cardiomyocyte Mechanics and Calcium Dynamics by Affecting Phospholamban Phosphorylation and ATP Production
Background/Aims: Dietary polyphenols from green tea have been shown to possess cardio-protective activities in different experimental models of heart diseases and age-related ventricular dysfunction. The present study was aimed at evaluating whether long term in vivo administration of green tea extracts (GTE), can exert positive effects on the normal heart, with focus on the underlying mechanisms. Methods: The study population consisted of 20 male adult Wistar rats. Ten animals were given 40 mL/day tap water solution of GTE (concentration 0.3%) for 4 weeks (GTE group). The same volume of water was administered to the 10 remaining control rats (CTRL). Then, in vivo and ex vivo measurements of cardiac function were performed in the same animal, at the organ (hemodynamics) and cellular (cardiomyocyte mechanical properties and intracellular calcium dynamics) levels. On cardiomyocytes and myocardial tissue samples collected from the same in vivo studied animals, we evaluated: (1) the intracellular content of ATP, (2) the endogenous mitochondrial respiration, (3) the expression levels of the Sarcoplasmic Reticulum Ca2+-dependent ATPase 2a (SERCA2), the Phospholamban (PLB) and the phosphorylated form of PLB, the L-type Ca2+ channel, the Na+-Ca2+ exchanger, and the ryanodine receptor 2. Results: GTE cardiomyocytes exhibited a hyperdynamic contractility compared with CTRL (the rate of shortening and re-lengthening, the fraction of shortening, the amplitude of calcium transient, and the rate of cytosolic calcium removal were significantly increased). A faster isovolumic relaxation was also observed at the organ level. Consistent with functional data, we measured a significant increase in the intracellular ATP content supported by enhanced endogenous mitochondrial respiration in GTE cardiomyocytes, as well as higher values of the ratios phosphorylated-PLB/PLB and SERCA2/PLB. Conclusions: Long-term in vivo administration of GTE improves cell mechanical properties and intracellular calcium dynamics in normal cardiomyocytes, by increasing energy availability and removing the inhibitory effect of PLB on SERCA2
The ATPase Inhibitory Factor 1 (IF1) regulates the expression of the mitochondrial Ca2+ uniporter (MCU) via the AMPK/CREB pathway
â˘IF1 regulates MCU-dependent mitochondrial Ca2+ uptake.
â˘IF1 loss induces MCU upregulation through activation of the AMPK/CREB pathway.
â˘OMA1 depletion restores physiological MCU levels and mitochondrial Ca2+ entry
An Innovative Hyperbaric Hypothermic Machine Perfusion Protects the Liver from Experimental Preservation Injury
Purpose. Hypothermic machine perfusion systems seem more effective than the current static storage to prevent cold ischemic liver injury. Thus, we test an innovative hyperbaric hypothermic machine perfusion (HHMP), which combines hyperbaric oxygenation of the preservation solution and continuous perfusion of the graft. Methods. Rat livers were preserved with Celsior solution according to 4 different modalities: normobaric static preservation; hyperbaric static preservation at 2 atmosphere absolute (ATA); normobaric dynamic preservation, with continuous perfusion; hyperbaric dynamic preservation, with continuous perfusion at 2 ATA. After 24âh cold preservation, we assessed different parameters. Results. Compared to baseline, livers preserved with the current static storage showed severe ultrastructural damage, glycogen depletion and an increased oxidative stress. Normobaric perfused livers showed improved hepatocyte ultrastructure and ameliorated glycogen stores, but they still suffered a significant oxidative damage. The addition of hyperbaric oxygen produces an extra benefit by improving oxidative injury and by inducing endothelial NO synthase (eNOS) gene expression. Conclusions. Preservation by means of the present innovative HHMP reduced the liver injury occurring after the current static cold storage by lowering glycogen depletion and oxidative damage. Interestingly, only the use of hyperbaric oxygen was associated to a blunted oxidative stress and an increased eNOS gene expression
Prevalence of thoracic vertebral fractures in hospitalized elderly patients with heart failure
ObjectiveHeart failure (HF) has been associated with increased risk of fragility fractures. Indeed, most literature data on fractures were based on an historical and clinical approach focused on the identification of peripheral fractures, whereas the risk of vertebral fractures in this clinical setting is still unclear.DesignCross-sectional study.AimTo evaluate the prevalence and determinants of radiological thoracic vertebral fractures in patients with HF.MethodsThe study includes 1031 elderly hospitalized patients (491 females and 540 males; median age, 75 years; range, 65â90; 430 patients with HF) who were evaluated for the presence of thoracic vertebral fractures by quantitative morphometric analysis, using chest X-ray routinely performed in the diagnostic work-up of HF.ResultsVertebral fractures were found in 166 patients (16.1%), the prevalence being significantly higher in patients with HF as compared with those without HF, both in females (30.9 vs 15.8%; P<0.001) and in males (16.4 vs 7.4%; P=0.001). The association between HF and vertebral fractures remained statistically significant (odds ratio, 2.14; 95% CI, 1.25â3.66; P=0.01) even after adjustment for age, sex, loop diuretic therapy, anticoagulant therapy, proton pump therapy, coexistent chronic obstructive pulmonary disease, diabetes mellitus, renal insufficiency, and chronic liver diseases. In patients with HF, vertebral fractures were positively correlated with female sex, duration of HF, ischemic heart disease, cigarette smoking, and treatment with anti-osteoporotic drugs, and inversely correlated with left ventricular ejection fraction.ConclusionsHospitalized patients suffering from HF are at higher risk of vertebral fractures than patients without HF in the same clinical context
The Mixed Vector Current Correlator <0|T(V^3_\mu V^8_\nu )|0> To Two Loops in Chiral Perturbation Theory
The isospin-breaking correlator of the product of flavor octet vector
currents, and , is computed to
next-to-next- to-leading (two-loop) order in Chiral Perturbation Theory. Large
corrections to both the magnitude and -dependence of the one-loop result
are found, and the reasons for the slow convergence of the chiral series for
the correlator given. The two-loop expression involves a single
counterterm, present also in the two-loop expressions for
and , which counterterm
contributes a constant to the scalar correlator . The
feasibility of extracting the value of this counterterm from other sources is
discussed. Analysis of the slope of the correlator with respect to using
QCD sum rules is shown to suggest that, even to two-loop order, the chiral
series for the correlator may not yet be well-converged.Comment: 32 pages, uses REVTEX and epsfig.sty with 7 uuencoded figures. Entire
manuscript available as a ps file at
http://www.physics.adelaide.edu.au/theory/home.html Also available via
anonymous ftp at ftp://adelphi.adelaide.edu.au/pub/theory/ADP-95-27.T181.p
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