Corrosion properties of Ca65-xMg17.5Zn17.5+x (x = 0, 2.5, 5) alloys

The aim of the paper is to study the effect of zinc addition on the corrosion behavior of Ca65–xMg17.5Zn17.5+x (x = 0, 2.5, 5 at.%) alloys in simulated physiological fluids at 37°C. The electrochemical measurements allowed to determine a corrosion potential, which showed a positive shift from –1.60 V for Ca65Mg17.5Zn17.5 alloy to –1.58 V for Ca60Mg17.5Zn22.5 alloy, adequately. The more significant decrease of hydrogen evolution was noticed for Ca60Mg17.5Zn22.5 alloy (22.4 ml/cm2) than for Ca62.5Mg17.5Zn20 and Ca65Mg17.5Zn17.5 samples (29.9 ml/cm2 and 46.4 ml/cm2), consequently. The corrosion products after immersion tests in Ringer’s solution during 1 h were identified by X-ray diffraction and X-ray photoelectron spectroscopy as calcium, magnesium oxides, carbonates, hydroxides and calcium hydrate

Thermal and magnetic propertiesof selected Fe-based metallic glasses

Purpose: The work presents a thermal stability characterization and soft magnetic properties analysis of selected Fe-based metallic glasses. Design/methodology/approach: The studies were performed on ribbons prepared by the planar flow casting technique, which is a method of continuous casting of the liquid alloy on a surface of turning copper based wheel. The methods of X-ray diffraction were used for the qualitative phase analysis. The thermal properties associated with crystallization temperature of the glassy alloys were measured using the differential thermal analysis. The magnetic properties were determined by the Maxwell-Wien bridge, fluxometer and VSM methods. Findings: The studied Fe72B20Si4B4 and Fe36Co36B19Si5Nb4 metallic glasses in as-cast state were fully amorphous. The Curie temperature (Tc) for Fe72B20Si4B4 alloy has a value of 582 K and Fe36Co36B19Si5Nb4 has higher Tc, which has a value of 605 K. The obtained magnetic properties allow to classify the studied amorphous alloys in as-cast state as soft magnetic materials. The coercive field of tested alloys has a value about 8 A/m. The maximum magnetic permeability of Fe72B20Si4B4 alloy (!max = 21500) is much higher than Fe36Co36B19Si5Nb4 metallic glasses (!max = 3200). Similarly, saturation magnetization of Fe72B20Si4B4 alloy (Bs = 1.04 T) is higher than Fe36Co36B19Si5Nb4 (Bs = 0.99 T) amorphous alloy. Practical implications: The studied glassy alloys are suitable materials for many electrical application in different elements of magnetic circuits and for manufacturing of sensors and precise current transformers. Originality/value: The obtained results confirm the utility of applied investigation methods in the thermal and magnetic properties analysis of examined amorphous alloys

Effects of maleimide-polyethylene glycol-modified human hemoglobin (MP4) on tissue necrosis in SKH1-hr hairless mice

<p>Abstract</p> <p>Objective</p> <p>Tissue hypoxia after blood loss, replantation and flap reperfusion remains a challenging task in surgery. Normovolemic hemodilution improves hemorheologic properties without increasing oxygen carrying capacity. Red blood cell transfusion is the current standard of treatment with its attendant risks. The aim of this study was to investigate the potential of the chemically modified hemoglobin, MP4, to reduce skin flap necrosis and its effect on selected blood markers and kidneys.</p> <p>Materials and methods</p> <p>Tissue ischemia was induced in the ear of hairless mice (n = 26). Hemodilution was performed by replacing one third of blood volume with the similar amount of MP4, dextran, or blood. The extent of non-perfused tissue was assessed by intravital fluorescent microscopy.</p> <p>Results</p> <p>Of all groups, MP4 showed the smallest area of no perfusion (in percentage of the ear ± SEM: 16.3% ± 2.4), the control group the largest (22.4% ± 3.5). Leukocytes showed a significant increase in the MP4 and dextran group (from 8.7 to 13.6 respectively 15.4*10⁹/l). On histology no changes of the kidneys could be observed.</p> <p>Conclusion</p> <p>MP4 causes an increase of leukocytes, improves the oxygen supply of the tissue and shows no evidence of renal impairment.</p

A 10-Year Retrospective Analysis of Methyl Aminolevulinate Photodynamic Therapy Consultation at the Hospital de Braga

Photodynamic therapy (PDT) is a well-established treatment for actinic keratosis (AK), basal cell carcinoma (BCC), and Bowen's disease (BD). The object of this study was to describe the results of a retrospective analysis of patients treated with methyl aminolevulinate PDT (MAL-PDT) with red light, over the past decade at the Hospital de Braga (Braga, Portugal)

Timing the multiple cell death pathways initiated by Rose Bengal acetate photodynamic therapy

Rose Bengal acetate photodynamic therapy (RBAc–PDT) induced multiple cell death pathways in HeLa cells through ROS and ER stress. Indeed, apoptosis was the first preferred mechanism of death, and it was triggered by at least four different pathways, whose independent temporal activation ensures cell killing when one or several of the pathways are inactivated. Apoptosis occurred as early as 1 h after PDT through activation of intrinsic pathways, followed by activation of extrinsic, caspase-12-dependent and caspase-independent pathways, and by autophagy. The onset of the different apoptotic pathways and autophagy, that in our system had a pro-death role, was timed by determining the levels of caspases 9, 8, 3 and 12; Bcl-2 family; Hsp70; LC3B; GRP78 and phospho-eIF2α proteins. Interestingly, inhibition of one pathway, that is, caspase-9 (Z-LEHD-FMK), caspase-8 (Z-IETD-FMK), pan-caspases (Z-VAD-FMK), autophagy (3-MA) and necrosis (Nec-1), did not impair the activation of the others, suggesting that the independent onset of the different apoptotic pathways and autophagy did not occur in a subordinated manner. Altogether, our data indicate RBAc as a powerful photosensitiser that induces a prolonged cytotoxicity and time-related cell death onset by signals originating from or converging on almost all intracellular organelles. The fact that cancer cells can die through different mechanisms is a relevant clue in the choice and design of anticancer PDT

Haemodynamics and Oxygenation of the Tumor Microcirculation

Abnormalities of the tumor vasculature and their consequences on the microenvironment of tumor cells impact on tumor progression and response to both blood-borne anti-cancer agents and radio-therapy, as well as making tumor blood vessels a target for therapy in their own right. Intravital microscopy of experimental tumors, most commonly grown in ‘window’ chambers, such as the dorsal skin fold chamber in mice and rats, enables investigations of tumor microcirculatory function. This is needed both to understand the molecular control of tumor vascular function and to measure the response of the vasculature to treatment. In particular, intravital microscopy enables parameters associated with blood supply, vascular permeability and oxygenation to be estimated, at high spatial and temporal resolution. In this chapter, methods used for measuring a range of these parameters, specific examples of their applications, the significance of findings and some of the limitations of the techniques are described