Carnitine deficiency and oxidative stress provoke cardiotoxicity in an ifosfamide-induced Fanconi Syndrome rat model

In addition to hemorrhagic cystitis, Fanconi Syndrome is a serious clinical side effect during ifosfamide (IFO) therapy. Fanconi syndrome is a generalized dysfunction of the proximal tubule which is characterized by excessive urinary excretion of glucose, phosphate, bicarbonate, amino acids and other solutes excreted by this segment of the nephron including L-carnitine. Carnitine is essential cofactor for β-oxidation of long-chain fatty acids in the myocardium. IFO therapy is associated with increased urinary carnitine excretion with subsequent secondary deficiency of the molecule. Cardiac abnormalities in IFO-treated cancer patients were reported as isolated clinical cases. This study examined whether carnitine deficiency and oxidative stress, secondary to Fanconi Syndrome, provoke IFO-induced cardiomyopathy as well as exploring if carnitine supplementation using Propionyl-L-carnitine (PLC) could offer protection against this toxicity. In the current study, an animal model of carnitine deficiency was developed in rats by D-carnitine-mildronate treatment Adult male Wistar albino rats were assigned to one of six treatment groups: the first three groups were injected intraperitoneally with normal saline, D-carnitine (DC, 250 mg/kg/day) combined with mildronate (MD, 200 mg/kg/day) and PLC (250 mg/kg/day), respectively, for 10 successive days. The 4th, 5th and 6th groups were injected with the same doses of normal saline, DC-MD and PLC, respectively for 5 successive days before and 5 days concomitant with IFO (50 mg/kg/day). IFO significantly increased serum creatinine, blood urea nitrogen (BUN), urinary carnitine excretion and clearance, creatine phosphokinase isoenzyme (CK-MB), lactate dehydrogenase (LDH), intramitochondrial acetyl-CoA/CoA-SH and thiobarbituric acid reactive substances (TBARS) in cardiac tissues and significantly decreased adenosine triphosphate (ATP) and total carnitine and reduced glutathione (GSH) content in cardiac tissues. In carnitine-depleted rats, IFO induced dramatic increase in serum creatinine, BUN, CK-MB, LDH, carnitine clearance and intramitochondrial acetyl-CoA/CoA-SH, as well as progressive reduction in total carnitine and ATP in cardiac tissues. Interestingly, PLC supplementation completely reversed the biochemical changes-induced by IFO to the control values. In conclusion, data from the present study suggest that: Carnitine deficiency and oxidative stress, secondary to Fanconi Syndrome, constitute risk factors and should be viewed as mechanisms during development of IFO-induced cardiotoxicity. Carnitine supplementation, using PLC, prevents the development of IFO-induced cardiotoxicity through antioxidant signalling and improving mitochondrial function

The Exprimental Parameters Effect on The Performance of Cromer Wheel System in Airconditioning Unit

The main aim of the present study is to design and test the dehumidify systemfor air-conditioning unit and testing rig to find out the performance of usingpolymer technique to control the inside conditions, that are represented by relativehumidity and temperature in testing room by using desiccant wheel (Cromer cycle),and testing the effect of some parameters which can improve the performance ofthis system. An air-conditioner unit of 2tons capacity was installed in this systemand used one type of desiccant material (silica gel) was used in this work. Twothicknesses of desiccant material and two widths (channels depth) were studied3.5mm with channel depth 5cm and 2.5 mm with channel depth 20 cm and wheelsdiameter of 90cm.Four rotational speeds for desiccant wheel were studied (36, 45,60, and 90) rph and the regeneration temperature was used to control the inletregeneration air temperature using a number of electrical heaters. The series of testshowed that, the best COP, efficiency and relative humidity control within theconditioned space was for the silica gel at thickness 2.5mm and channel depth20cm. The maximum adsorption and desorption rate was 0.5427g/kg and1.322g/kg respectively at 36 rph and (36.5 oC) regeneration temperature and thebest COP of A/C was about (5.12) at 36 rph and (42 oC) regeneration temperature.Experimentally the best sensible and total efficiency that can be achieved was(18.1%) and (17.98%) at 45 rph and (30.6 oC) regeneration temperature and(17.88%), (17.76%) at 36rph and (30.91oC) regeneration temperature. The bestlatent efficiency was (6.2 %) at 45 rph and (43.26 oC) regeneration temperatur

Temperature Dependent Surface Modification of Tungsten Exposed to High-Flux Low-Energy Helium Ion Irradiation

Nuclear fusion is a great potential energy source that can provide a relatively safe and clean limitless supply of energy using hydrogen isotopes as fuel material. ITER (international thermonuclear experimental reactor) is the world first fusion reactor currently being built in France. Tungsten (W) is a prime candidate material as plasma facing component (PFC) due to its excellent mechanical properties, high melting point, and low erosion rate. However, W undergoes a severe surface morphology change when exposed to helium ion (He+) bombardment under fusion conditions. It forms nanoscopic fiber-form structures, i.e., fuzz on the surface. Fuzz is brittle and can easily contaminate the plasma, and therefore preventing the fusion chain reaction. In this study, we report on the effect of temperature on the surface morphology evolution of W coatings under low energy He+ ion irradiation, relevant to fusion conditions. Submicron thickness W films have been deposited on Si (100) at room temperature using RF sputtering deposition technique. Several samples were cut from the same wafer and exposed to 100 eV He+ ions having a constant flux of 1.2 × 1021 ions m−2 s−1 (total fluence of 4.3 × 1024 ions m−2) at several temperatures in the range of 1073 – 1273 K. During each ion irradiation experiments the applied sample temperature were constant throughout that experiment. Post ion-irradiation samples (including pristine) were characterized using field emission scanning electron microscopy (FE-SEM), X-ray photoelectric spectroscopy (XPS), and optical reflectivity measurements for monitoring the changes in surface morphology, chemical composition, and surface roughness/optical properties, respectively. Our analysis shows a sequential enhancement in W fuzz density, sharpness, and protrusions from the film surface, with increasing sample temperature, during helium ion irradiation. Ex-situ XPS study shows the evidence of W2O3 phase formation due to natural oxidation of W fuzz in the open atmosphere, for all irradiated samples. The study is significant in the understanding processes of fuzz formation on high-Z refractory metals for fusion applications. In addition, the observed W2O3 fuzz structure may have potential applications in solar power concentration technology and in water splitting for hydrogen production

Nitrogen storage and use of biochemical indices to assess nitrogen deficiency and growth rate in natural plankton populations

Various newly developed indicators of N deficiency, physiological state (approximate growth rate), and N source for growth were measured during five cruises to Dabob Bay, Washington from early spring to summer. Although nitrate and ammonium in the surface layer were depleted early in the spring, the plankton populations never became extremely N deficient, as indicated by high intracellular amino acid/protein ratios. However, growth rates, estimated from protein/DNA or RNA/DNA ratios, were usually low unless nitrate concentrations were high or had recently been high, as indicated by large intracellular nitrate pools or high nitrate reductase activities. High growth rates were observed during the spring bloom or as a result of the sporadic supply of nitrate to the euphotic zone, which was inferred from measurements of biochemical indicators on several cruises after the spring bloom. The sporadic supply of nitrate could account for the lack of N deficiency in these populations and mask diel periodicity in N utilization. These results demonstrate that biochemical indicators can be easily measured in the field and that variations in indicators such as intracellular amino acid/protein, protein/DNA, RNA/DNA ratios, NR activities and intracellular nitrate concentrations are an aid in understanding plankton dynamics

Two Loop Low Temperature Corrections to Electron Self Energy

We recalculate the two loop corrections in the background heat bath using real time formalism. The procedure of the integrations of loop momenta with dependence on finite temperature before the momenta without it, has been followed. We determine the mass and wavefunction renormalization constants in the low temperature limit of QED, for the first time with this preferred order of integrations. The correction to electron mass and spinors in this limit is important in the early universe at the time of primordial nucleosynthesis as well as in astrophysics.Comment: 8 pages and 1 figure to appear in Chinese Physics

The role of Majorana CP phases in the bi-maximal mixing scheme -hierarchical Dirac mass case-

We discuss the energy scale profile of the bi-maximal mixing which is given at the GUT energy scale in the minimal SUSY model, associated with an assumption that Y_nu^dagger Y_nu is diagonal, where Y_nu is the neutrino-Yukawa coupling matrix. In this model, the Dirac mass matrix which appears in the seesaw neutrino mass matrix is determined by three neutrino masses, two relative Majorana phases and three heavy Majorana masses. All CP phases are related by two Majorana phases. We show that the requirement that the solar mixing angle moves from the maximal mixing at GUT to the observed one as the energy scale decreases by the renormalization effect. We discuss the leptogenesis, and the lepton flavor violation process by assuming the universal soft breaking terms.Comment: 19 pages, 2 figure

Neutrino Anomalies and Quasi-Dirac neutrinos

We discuss possibility of describing solar, atmospheric and LSND results with four neutrinos forming two quasi-degenerate pairs. The simplest versions of this 2+2 scheme with either $\nu_e$ or $\nu_\mu$ mixing exclusively with sterile neutrino is disfavored by the SNO and atmospheric neutrino results respectively. A generalized scheme with sterile state participating in both the solar and atmospheric oscillations is still allowed. We show thasolar and atmospheric oscillations is still allowed. We show that the complex pattern of mixing needed for this purpose follows from a simple L_e+L_\mu-L_\tau-L_s symmetry. Specific form of L_e+L_\mu-L_\tau-L_s symmetric mass matrix is determined from experimental results. Two theoretical schemes which lead to this form and a proper breaking of L_e+L_\mu-L_\tau-L_s symmetry are discussed.Comment: 15 pages, LATEX, minor corrections; addition of few reference