Aims/hypothesis The aim of this study was to confirm a link between mitochondrial dysfunction and type 2 diabetes. Materials and methods Cellular levels of mitochondrial proteins, cellular ...mitochondrial DNA content, and mitochondrial function and morphology were assessed by MitoTracker staining and electron microscopy, in white adipose tissue of 12-week-old male wild-type, obese (ob/ob), and diabetic (db/db) mice. Results Levels of mitochondrial proteins were found to be very similar in the livers and muscles of all the mice studied. However, levels were greatly decreased in the adipocytes of db/db mice, but not in those of the wild-type and ob/ob mice. Levels of mitochondrial DNA were also found to be considerably reduced in the adipocytes of db/db mice. MitoTracker staining and under electron microscopy revealed that the number of mitochondria was reduced in adipocytes of db/db mice. Respiration and fatty acid oxidation studies indicated mitochondrial dysfunction in adipocytes of db/db mice. Interestingly, there was an increase in mitochondria and mitochondrial protein production in adipocytes of db/db mice treated with rosiglitazone, an agent that enhances insulin sensitivity. Conclusions/interpretation Taken together, these data indicate that mitochondrial loss in adipose tissue is correlated with the development of type 2 diabetes.
The hypothesis of cancer stem cells has been proposed to explain the therapeutic failure in a variety of cancers including lung cancers. Previously, we demonstrated acquisition of ...epithelial-mesenchymal transition, a feature highly reminiscent of cancer stem-like cells, in gefitinib-resistant A549 cells (A549/GR). Here, we show that A549/GR cells contain a high proportion of CXCR4+ cells that are responsible for having high potential of self-renewal activity in vitro and tumorigenicity in vivo. A549/GR cells exhibited strong sphere-forming activity and high CXCR4 expression and SDF-1α secretion compared with parent cells. Pharmacological inhibition (AMD3100) and/or siRNA transfection targeting CXCR4 significantly suppressed sphere-forming activity in A549 and A549/GR cells, and in various non-small cell lung cancer (NSCLC) cell lines. A549/GR cells showed enhanced Akt, mTOR and STAT3 (Y705) phosphorylation. Pharmacological inhibition of phosphatidyl inositol 3-kinase or transfection with wild-type PTEN suppressed phosphorylation of Akt, mTOR and STAT3 (Y705), sphere formation, and CXCR4 expression in A549/GR cells, whereas mutant PTEN enhanced these events. Inhibition of STAT3 by WP1066 or siSTAT3 significantly suppressed the sphere formation, but not CXCR4 expression, indicating that STAT3 is a downstream effector of CXCR4-mediated signaling. FACS-sorted CXCR4+ A549/GR cells formed many large spheres, had self-renewal capacity, demonstrated radiation resistance in vitro and exhibited stronger tumorigenic potential in vivo than CXCR4- cells. Lentiviral-transduction of CXCR4 enhanced sphere formation and tumorigenicity in H460 and A549 cells, whereas introduction of siCXCR4 suppressed these activities in A549/GR cells. Our data indicate that CXCR4+ NSCLC cells are strong candidates for tumorigenic stem-like cancer cells that maintain stemness through a CXCR4-medated STAT3 pathway and provide a potential therapeutic target for eliminating these malignant cells in NSCLC.
Despite the growing research on biomolecule-inorganic nanoflowers for multiple applications, it remains challenging to control their development on stationary platforms for potential portable and ...wearable devices. In this work, the self-assembly of Cu3(PO4)2–bovine serum albumin hybrid nanoflowers is facilitated by an alumina platform whose surface is tailored by wet plasma electrolysis. This allows an interlocking of hybrid nanoflowers with the surface motifs of the solid platform, resulting in a hierarchy similar to nanocarnation (NC) petals on an inorganic bed. Density functional theory calculations are performed to reveal the primary bonding mode between the organic and inorganic components and to identify the active sites of the protein structure in order to provide mechanistic insights that can explain self-assembly of NCs overall. The hybrid architecture displays an adaptive microstructure in different aqueous environment, giving rise to a dual-function based on its electrochemical stability and catalytic activity toward radical degradation of organic pollutant.
The RENO experiment has analyzed about 500 live days of data to observe an energy dependent disappearance of reactor νover ¯_{e} by comparing their prompt signal spectra measured in two identical ...near and far detectors. In the period between August of 2011 and January of 2013, the far (near) detector observed 31 541 (290 775) electron antineutrino candidate events with a background fraction of 4.9% (2.8%). The measured prompt spectra show an excess of reactor νover ¯_{e} around 5 MeV relative to the prediction from a most commonly used model. A clear energy and baseline dependent disappearance of reactor νover ¯_{e} is observed in the deficit of the observed number of νover ¯_{e}. Based on the measured far-to-near ratio of prompt spectra, we obtain sin^{2}2θ_{13}=0.082±0.009(stat)±0.006(syst) and |Δm_{ee}^{2}|=2.62_{-0.23}^{+0.21}(stat)_{-0.13}^{+0.12}(syst)×10^{-3} eV^{2}.
Polylactic acid (PLA), one of the well-known biodegradable polyesters, has been studied extensively for tissue engineering and drug delivery systems, and it was also used widely in human medicine. A ...new method to synthesize PLA (ring-opening polymerization), which allowed the economical production of a high molecular weight PLA polymer, broadened its applications, and this processing would be a potential substitute for petroleum-based products. This review described the principles of the polymerization reactions of PLA and, then, outlined the various materials properties affecting the performance of PLA polymer, such as rheological, mechanical, thermal, and barrier properties as well as the processing technologies which were used to fabricate products based on PLA. In addition, the biodegradation processes of products which were shaped from PLA were discussed and reviewed. The potential applications of PLA in the medical fields, such as tissue engineering, wound management, drugs delivery, and orthopedic devices, were also highlighted.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
In an endeavour to study the influence of vanadium pentoxide (V2O5) on 6061 Al alloy, a silicate-based electrolyte with suspended V2O5 particles was employed during plasma electrolytic oxidation for ...90 and 180 s, and the electrochemical stability of the resultant oxide layers was investigated. The addition of V2O5 particles reduced the number of microdefects found in the oxide layer after electrolysis. This was attributed mainly to the incorporation of V2O5 particles whose tendency was observed to be increased with time. Surface analysis revealed that the oxide layer comprised vanadium oxides (VxOy) in the oxidation state of +5 and + 4 referred to V2O5 and VO2, respectively. The formation of VO2, which was evident in longer processing time, would be associated to the decomposition of the V2O5 particles by high energy plasma. Accordingly, when a suitable combination of V2O5 and VO2 was achieved in 180 s, an attractive dark-green layer would be obtained. Finally, the electrochemical stability of the samples was improved with the increase of vanadium content, which was interpreted on the basis of Tafel extrapolation and equivalent circuit model.
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•The influence of V2O5 particles on the oxide layer was significant.•Suitable composition of V2O5 and VO2 endowed dark-green color.•The electrochemical stability of Al alloy was improved as VxOy increased.•With increase of vanadium oxides, the corrosion resistance enhanced significantly.
The present study investigates how sub-zero temperature affects the formation of the oxide layer of pure magnesium and subsequently alters their corrosion performance. To this end, a series of plasma ...electrolysis is carried out in alkaline-silicate electrolyte with two different temperatures of −5 and 25 °C. In contrast to the popular findings that low temperatures during anodic oxidation promotes superior corrosion protection, the present results show that the corrosion resistance of the sample processed at sub-zero condition is inferior to that processed at room temperature. In order to discuss such anomaly of the corrosion resistance, microstructural factors, including morphologies, compactness, and composition of the oxide layer would be taken into account.
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•Sub-zero electrolyte induced the formation of compact oxide layer.•The compactness of the oxide layer increased as temperature decreased.•Formation of Mg2SiO4 was suppressed in sub-zero electrolyte.•Contribution of Mg2SiO4 is significant for corrosion protection.
This study investigated the formation mechanism of the oxide layer generated by micro-arc oxidation (MAO) considering surface roughness of AZ31 Mg alloy. For this purpose, a series of MAO treatments ...under alternating current in a silicate-based electrolyte were performed on two present samples with grooved and flat surfaces. The time-voltage response presented that the grooved sample reached the breakdown voltage earlier than the flat sample. This indicated the appearance of micro-discharges on the grooved sample occurred earlier than that of the flat sample since the oxide fragments nucleated preferentially at the ridge areas where electrons were concentrated severely under high electrical field. The oxide layer of the grooved sample was relatively less dense than that of the flat sample. This was attributed to the fact that the oxide layer of the grooved sample was likely to grow with ease on pre-existing coating layer whereas the oxide layer of the flat sample developed conformably throughout the whole areas. Thus, the growth rate of the grooved sample was higher than that of the flat sample, which agreed well with micro-discharge activities. Such formation mechanism was proposed in relation to nucleation and growth of the oxide layer formed on different surface structures.
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•Role of surface roughness on formation of the oxide layer is significant.•Nucleation of the oxide layer is triggered as surface roughness increases.•Growth rate of the oxide layer at the valley is higher than that at the ridge.•The thick and porous oxide layer was made as surface roughness increases.
The present work investigated the influence of SiO2 and ZrO2 incorporated nanoparticles on the coating structure and the corrosion behavior of 6061 Al alloy coated by plasma electrolytic oxidation ...(PEO). To achieve this purpose, a set of PEO treatments were conducted in alternating current condition at a constant current density of 130 mAcm−2 in phosphate electrolytes containing each and both nanoparticles, respectively. Microstructure observations revealed that when SiO2 or/and ZrO2 nanoparticles were added to the electrolyte, both size and fraction of micropores tended to be decreased, which would be attributed to the incorporation of nanoparticles. SiO2 nanoparticles were preferentially embedded in the vicinity of micropores, meanwhile ZrO2 nanoparticles preferentially filled the cracks. m-ZrO2 was mostly converted to o-ZrO2 while SiO2 were partly converted to o-SiO2 and another part to mullite. Based on potentiodynamic polarization tests in 3.5 wt% NaCl solution, the coatings containing both SiO2 and ZrO2 nanoparticles exhibited excellent corrosion protection properties due to the combination of their roles as the micropores blocker and cracks filler so that the microstructural defects were minimized.
•SiO2 and ZrO2 nanoparticles were incorporated into the oxide layer via plasma electrolytic oxidation.•Micropores were closed by the dual incorporation of SiO2 and ZrO2.•Corrosion properties of 6061 Al alloy were enhanced by the dual incorporation of SiO2 and ZrO2.
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