Molecular quantum spintronics: supramolecular spin valves based on single-molecule magnets and carbon nanotubes

We built new hybrid devices consisting of chemical vapor deposition (CVD) grown carbon nanotube (CNT) transistors, decorated with TbPc(2) (Pc = phthalocyanine) rare-earth based single-molecule magnets (SMMs). The drafting was achieved by tailoring supramolecular π-π interactions between CNTs and SMMs. The magnetoresistance hysteresis loop measurements revealed steep steps, which we can relate to the magnetization reversal of individual SMMs. Indeed, we established that the electronic transport properties of these devices depend strongly on the relative magnetization orientations of the grafted SMMs. The SMMs are playing the role of localized spin polarizer and analyzer on the CNT electronic conducting channel. As a result, we measured magneto-resistance ratios up to several hundred percent. We used this spin valve effect to confirm the strong uniaxial anisotropy and the superparamagnetic blocking temperature (T(B) ~ 1 K) of isolated TbPc(2) SMMs. For the first time, the strength of exchange interaction between the different SMMs of the molecular spin valve geometry could be determined. Our results introduce a new design for operable molecular spintronic devices using the quantum effects of individual SMMs.     

Microstructural and phase transformations during sintering of a phillipsite rich zeolitic tuff

Microstructural and phase transformations during sintering of a Phillipsite rich zeolitic tuff, from Tenerife, Canary Islands, was investigated in order to their utilization in ceramic manufacturing industries. Green samples were obtained from powders and pressed at 150 MPa and heat-treated for 1 hour in the temperature range between 900-1080 °C. The zeolitic tuffs show endothermic peaks at about 100 °C and 200 °C, corresponding to dehydration of zeolitic water observed in the thermo- gravimetric curves and at ∼700 °C a small endothermic peak was identified corresponding to the structural breakdown of Phillipsite. According to the dilatometric traces, at about 870 °C, sintering of solid particles starts and a linear shrinkage of about 6% is reached at about 1050 °C. The maximum absolute and apparent densities were obtained after sintering at 1040 °C (absolute density = 2.59 g/cm³; apparent density = 2.33 g/cm³). Over this temperature, the sample heat-treated at 1060 °C, density results show a decreasing trend. The chemical composition of studied zeolitic tuffs make possible the liquid phase formation during heat-treatment, through the supplement of alkaline oxides. SEM image of the sample obtained at 1040 °C shows a zone with micro-crystallinity around the boundary of Sanidine grain highlighting the beginning of the phase transition from Sanidine, to Microcline. Heat-treatment effect of zeolitic tuff leads to the decomposition of Phillipsite and Sanidine and the formation of a new crystal phase of Hematite.     

Fatty Acid Status Determination by Cheek Cell Sampling Combined with Methanol-Based Ultrasound Extraction of Glycerophospholipids

Tissue and blood fatty acid compositions are used as biological markers of fatty acid intakes to improve dietary assessments. These approaches are invasive and not well accepted, particularly in infants and young children. We developed a sensitive method for the analysis of fatty acids in cheek cell glycerophospholipids, which includes significant improvements of cell sampling, non-chromatographic isolation of glycerophospholipids and base-catalyzed synthesis of fatty acid methyl esters. Sphingophospholipids are not detected by this method. This enables a highly accurate determination of cheek cell glycerophospholipid fatty acids, even if cell numbers are limited. Coefficients of variation for fatty acids contributing more than 0.3% to total glycerophospholipid fatty acids are below 10% in samples with more than 10⁵ cells. Good correlations were shown between docosahexaenoic and eicosapentaenoic acid percentages in cheek cell and plasma glycerophospholipids (r = 0.83 and 0.64, respectively; P < 0.001) with a linear relationship over the whole concentration range observed in adult study participants (n = 29). Cheek cell sampling is non-invasive and can easily be applied in infants. The accuracy and reliability of this new method is comparable to conventional invasive methods for the determination of the n-3 fatty acid status in humans, and it is well applicable in interventional or epidemiological studies.     

Melt processing of ethylene–vinyl acetate/banana starch/Cloisite 20A organoclay nanocomposite films: structural,thermal and composting behavior

This work shows the preparation of ethylene vinyl acetate copolymer/banana starch/Cloisite 20A organoclay (EVA/starch/C20A) nanocomposites by melt processing. Wide angle X-ray diffraction (WAXD), field emission scanning electron microscopy (FE-SEM), differential scanning calorimetry and thermogravimetric analysis were used to characterize the obtained nanocomposites. Mechanical properties were also determined. In addition, the performance of the nanocomposite films under composting was preliminarily studied; it was conducted using the soil burial test method. Despite knowing that the starch is difficult to process by extrusion, nanocomposite films with high homogeneity were obtained. In this case, C20A organoclay acts as an effective surfactant to make the starch natural polymer compatible with the EVA synthetic polymer. The good compatibility between EVA, starch and C20A clay was also deduced by the formation of intercalated and intercalated-exfoliated structures determined by WAXD and FE-SEM. Physical evidence of the damage in EVA/starch/C20A nanocomposite films after the composting test was observed. It is worth noting that despite the absence of starch, the EVA/C20A nanocomposite film, used as a control, also showed surface damage. This behavior is related to the organic modifier linked to clay C20A, which contains molecules derived from fatty acids that can be used as a food source for microorganisms.

     

Portrait of Cancer Stem Cells on Colorectal Cancer: Molecular Biomarkers,Signaling Pathways and miRNAome

Colorectal cancer (CRC) is a leading cause of cancer death worldwide, and about 20% is metastatic at diagnosis and untreatable. Increasing evidence suggests that the heterogeneous nature of CRC is related to colorectal cancer stem cells (CCSCs), a small cells population with stemness behaviors and responsible for tumor progression, recurrence, and therapy resistance. Growing knowledge of stem cells (SCs) biology has rapidly improved uncovering the molecular mechanisms and possible crosstalk/feedback loops between signaling pathways that directly influence intestinal homeostasis and tumorigenesis. The generation of CCSCs is probably connected to genetic changes in members of signaling pathways, which control self-renewal and pluripotency in SCs and then establish function and phenotype of CCSCs. Particularly, various deregulated CCSC-related miRNAs have been reported to modulate stemness features, controlling CCSCs functions such as regulation of cell cycle genes expression, epithelial-mesenchymal transition, metastasization, and drug-resistance mechanisms. Primarily, CCSC-related miRNAs work by regulating mainly signal pathways known to be involved in CCSCs biology. This review intends to summarize the epigenetic findings linked to miRNAome in the maintenance and regulation of CCSCs, including their relationships with different signaling pathways, which should help to identify specific diagnostic, prognostic, and predictive biomarkers for CRC, but also develop innovative CCSCs-targeted therapies.     

Development of UV-curable ZrO2 slurries for additive manufacturing (LCM-DLP) technology

Digital Light Processing (DLP) is a powerful technique for the preparation of ceramic parts with high resolution and complex shapes. In the last years, the development of photosensitive slurries for the production of ceramics with good mechanical properties has received much attention. In this work, ZrO₂ UV-curable slurries were prepared in two steps for their application in DLP. Firstly, the surface modification of the ZrO₂ particles was carried out using a dispersing agent and secondly, the modified powder was dispersed in an acrylate based mixture. Parts with different geometries were printed and a resolution experiment was also carried out in order to determine the limitations of the slurry. Finally, 30 bars were produced to study the mechanical properties of the sintered parts (ρ = 6.00 ± 0.01 g/mL) by 4-point bending tests and Weibull analysis, obtaining a flexural strength σ₀ = 741 (718–765) MPa with a Weibull coefficient of 11.4.     

Oxidation Behavior of Aerospace Materials in High Enthalpy Flows Using an Oxyacetylene Torch Facility

The oxyacetylene torch facility is used to measure the ablation rates of graphite and the surface temperatures of different aerospace materials. The free‐stream flame environment is characterized as a function of flame chemistry for heat flux, pO₂, and flow velocity. Measured ablation rates for graphite increase as a function of increasing heat flux and pO₂, which are validated by applying an oxygen diffusion based model. The model uses experimentally measured values for temperature, pO₂, and gas velocity in order to confirm torch testing results are reliable and reproducible. Surface temperatures of ultra‐high temperature ceramic composites are measured as a function of increasing heat flux and show an enthalpic cooling effect on the flame during oxidation testing.     

Novel Heterogenized Palladium(II) Complexes Anchored to Polymer Matrices Functionalized with Bis(diphenylphosphino)methane Moieties

The synthesis and structural characterization of a novel bidentate ligand such as bis(diphenylphosphino) methane bound to a cross-linked styrene/divinylbenzene resin and to linear poly(styrene) are reported. Moreover, the anchoring of palladium acetate to the above polymeric ligands is described and the structure of the heterogenized palladium(II) complexes obtained is proposed.     

Polyphenolic fractions improve the oxidative stability of microencapsulated linseed oil

The main objective of this study was to evaluate the effect of incorporating polyphenolic‐enriched fractions from murta leaves on the oxidative stability of linseed oil microencapsulated by spray drying. For this purpose, polyphenol‐enriched fractions from murta leaves were separated by gel permeation chromatography and chemically characterized. The oxidative stability of microencapsulated linseed oil (MLO) with antioxidants was evaluated in storage conditions at 25°C for 40 days. The antioxidant effects of the polyphenolic fractions and commercial antioxidants (BHT and trolox) on microencapsulated oil were evaluated by the value of conjugated dienes, peroxide, and p‐anisidine. In the initiation step of the oxidation, no significant oxidation delay (p>0.05) in MLO containing fractions F₆, F₈, or BHT and trolox was observed. However, in the termination step of the oxidation, the addition of fractions F₆, F₈, and BHT and trolox decreases significantly (p ≤ 0.05) the rancidity in MLO. Furthermore, the results of this study demonstrated the importance of the addition of natural antioxidants such as fractions of murta leaf extract in microencapsulated linseed oil to increase its resistance to oxidation. Practical applications: For incorporating linseed oil, a source of omega‐3 fatty acids, in the diet it is necessary to protect it against oxidative rancidity, the main cause of deterioration that affects food with a high unsaturated fat content. Microencapsulation is effective in retarding or suppressing the oxidation of unsaturated fatty acids and natural plants extracts are effective in inhibiting the lipid oxidation of microencapsulated oil. The use of process technology and a natural additive is expected to increase storage stability and enable its use in dry foods such as instant products. Linseed oil can be used in human nutrition as well as in animal feed as a replacement for fish oil.