Synthesis of Nanophased Metal Oxides in Supercritical Water: Catalysts for Biomass Conversion

Nanoparticles of zinc oxide-based materials (ZnO, ZnAl₂O₄) with various morphologies were synthesized in supercritical water (SCW) with a flow-type apparatus and in sub- and supercritical water with a batch reactor. In the flow-type apparatus, smaller particles were obtained. Depending on the precursors, the morphology of crystallites is rod, hexagonal, or rectangular shaped. ZnAl₂O₄ was synthesized with a high specific surface area ( S _BET) reaching 210 m²/g and nanocrystallite sizes ≤10 nm. The KOH concentration played a major role in the formation of ZnO and ZnAl₂O₄ phases. Then, the synthesized materials were used as catalysts for the biomass conversion by the oxidation process to produce hydrogen.     

Approach to the lifetime assessment of the bayonet back plate for IFMIF target

The IFMIF facility is aimed at the production of high flux (10¹⁸ n/m²/s) of 14 MeV neutrons to test the candidate Fusion materials under significant neutron damage, up to 50 dpa/year. The conceptual configuration of the IFMIF target, based on the bayonet back plate (BP), has been developed in the past years by several authors. The appropriate engineering design of the back plate, to be developed in the EVEDA (Engineering Validation and Engineering Design Activities) phase, would require a very high level of knowledge on the materials behaviour under irradiation, that will be acquired only after some years of IFMIF experimental activities. For this reason the back plate, which is primarily invested by the highest IFMIF neutron flux, has to be considered a sacrificial component. In spite of its systematic replacement, the engineering design has to be optimised and the lifetime analysis has to be made carefully, in order to credibly estimate the expected replacement frequency. Since the replacement time interval must be conservatively shorter than the back plate lifetime and, at each replacement, the facility has to be stopped for, at least, one week and subjected to risky and uncomfortable operations, it is necessary to perform a trustworthy analysis of the lifetime. To this purpose the various interconnections between the main damaging causes are discussed in order to evidence the most plausible reasons of back plate malfunctioning. Due to the lack of knowledge in some fields and the early stage of design, the analysis is only semi-quantitative. The analysis, which accounts for erosion/corrosion, hydraulic stability, neutron damage and thermo-mechanical stress as the main damaging causes, evidences also the research areas which deserve foremost attention during the EVEDA phase. The considered malfunctions are: lithium boiling, burning/piercing of the back plate, non-sufficient neutron flux, brittle rupture of the back plate, creep rupture, loss of tightness of the back plate sealing.     

Development of remote handling technology of liquid lithium target and replaceable back plate with lip seal in IFMIF-EVEDA

The IFMIF is an accelerator-based intense neutron source for testing candidate fusion materials. Intense neutrons equivalent to neutron irradiation damage of about 50 dPa/y are emitted inside the Li flow through a back plate. Around the back plate, a lip seal made of 316 L is welded by laser-welding system for replacement by remote handling. The back plate will be designed for replacement at least every year. According to material tests of the lip seal weld joint (316 L/316 L) at room temperature, significant deterioration was not observed. Further investigation of the welding process of the lip seal such as a welding direction and a welding joint shape is in progress. Remote handling procedure of the back plate is examined. At first, three lip seal joints of connection piping will be cut by the laser cutting/welding device and then the target assembly with the back plate will be moved to a hot cell. The back plate lip seal will be cut by the laser arm in the hot cell. After machining and Li cleaning of the lip seal, a new back plate will be welded and moved to test cell/target room.     

PARP Inhibitor Decreases Akt Phosphorylation and Induces Centrosome Amplification and Chromosomal Aneuploidy in CHO-K1 Cells

Cancer cells are known to have chromosomal number abnormalities (aneuploidy), a hallmark of malignant tumors. Cancer cells also have an increased number of centrosomes (centrosome amplification). Paradoxically, cancer therapies, including γ-irradiation and some anticancer drugs, are carcinogenic and can induce centrosome amplification and chromosomal aneuploidy. Thus, the processes of carcinogenesis and killing cancer cells might have some mechanisms in common. Previously, we found that the inhibitors of polyADP-ribosylation, a post-translational modification of proteins, caused centrosome amplification. However, the mechanism of action of the inhibitors of polyADP-ribosylation is not fully understood. In this study, we found that an inhibitor of polyADP-ribosylation, 3-aminobenzamide, caused centrosome amplification, as well as aneuploidy of chromosomes in CHO-K1 cells. Moreover, inhibitors of polyADP-ribosylation inhibited AKT phosphorylation, and inhibitors of AKT phosphorylation inhibited polyADP-ribosylation, suggesting the involvement of polyADP-ribosylation in the PI3K/Akt/mTOR signaling pathway for controlling cell proliferation. Our data suggest a possibility for developing drugs that induce centrosome amplification and aneuploidy for therapeutic applications to clinical cancer.     

Antisense Oligonucleotide Induction of the hnRNPA1b Isoform Affects Pre-mRNA Splicing of SMN2 in SMA Type I Fibroblasts

Spinal muscular atrophy (SMA) is a severe, debilitating neuromuscular condition characterised by loss of motor neurons and progressive muscle wasting. SMA is caused by a loss of expression of SMN1 that encodes the survival motor neuron (SMN) protein necessary for the survival of motor neurons. Restoration of SMN expression through increased inclusion of SMN2 exon 7 is known to ameliorate symptoms in SMA patients. As a consequence, regulation of pre-mRNA splicing of SMN2 could provide a potential molecular therapy for SMA. In this study, we explored if splice switching antisense oligonucleotides could redirect the splicing repressor hnRNPA1 to the hnRNPA1b isoform and restore SMN expression in fibroblasts from a type I SMA patient. Antisense oligonucleotides (AOs) were designed to promote exon 7b retention in the mature mRNA and induce the hnRNPA1b isoform. RT-PCR and western blot analysis were used to assess and monitor the efficiency of different AO combinations. A combination of AOs targeting multiple silencing motifs in hnRNPA1 pre-mRNA led to robust hnRNPA1b induction, which, in turn, significantly increased expression of full-length SMN (FL-SMN) protein. A combination of PMOs targeting the same motifs also strongly induced hnRNPA1b isoform, but surprisingly SMN2 exon 5 skipping was detected, and the PMO cocktail did not lead to a significant increase in expression of FL-SMN protein. We further performed RNA sequencing to assess the genome-wide effects of hnRNPA1b induction. Some 3244 genes were differentially expressed between the hnRNPA1b-induced and untreated SMA fibroblasts, which are functionally enriched in cell cycle and chromosome segregation processes. RT-PCR analysis demonstrated that expression of the master regulator of these enrichment pathways, MYBL2 and FOXM1B, were reduced in response to PMO treatment. These findings suggested that induction of hnRNPA1b can promote SMN protein expression, but not at sufficient levels to be clinically relevant.     

Biological evaluation of mechanically deboned chicken meat protein quality

Mechanically deboned chicken meat (MDCM) is a meat product obtained by crushing tissues after meat removal and is largely used in meat products. Protein quality of flour prepared from defatted MDCM and from fresh chicken breast meat (FCBM) was chemically and biologically evaluated by rat growth and nitrogen balance studies. Proximate chemical composition, on a dry basis, of MDCM and FCBM showed protein contents of 90.5% and 82.2%, lipid contents of 3.0% and 13.2% and ash contents of 6.1% and 4.2%, respectively. There was a relatively good balance of essential amino acids in both samples although lysine was in low concentration in MDCM being a limiting amino acid. Feeding of flour diets resulted in high protein efficiency ratio, a high net protein utilization and high nitrogen balance, thus showing a high biological value and also high true digestibility and, consistently, NPU for both samples is similar to casein.     

Smoking practices, risk perception of smoking, and environmental tobacco smoke exposure among 6th-grade students in Ciudad Juárez, Mexico.

This study assessed the smoking practices, risk perception of smoking, and environmental tobacco smoke (ETS) exposure among adolescents in Ciudad Juárez, Mexico. We used a cross-sectional method to examine the smoking practices, risk perception of smoking, and ETS exposure of 6th-grade students (N=506), aged 11-13 years, attending six randomly selected middle schools. Schools were classified by school setting (i.e., public vs. private) and socioeconomic status (SES; i.e., low, middle, or high). The results indicated that 6th-grade students attending a public, low-SES school setting in Ciudad Juárez not only exhibited significantly higher rates of ETS exposure at home and in public places (p<.01) but also were more likely to have tried smoking (p<.01) and to be current smokers (p<.01), and were less likely to support a ban on smoking in public places (p<.01), compared with students who attended a private school or a public, middle- or high-SES school setting. These results provide further evidence that public health interventions to prevent initiation of smoking and to assist in smoking cessation among adolescents and to reduce their ETS exposure at home and in public need to target all school-aged students, especially those attending school in a low-SES settings.     

Hypoxia Differently Affects TGF-β2-Induced Epithelial Mesenchymal Transitions in the 2D and 3D Culture of the Human Retinal Pigment Epithelium Cells

The hypoxia associated with the transforming growth factor-β2 (TGF-β2)-induced epithelial mesenchymal transition (EMT) of human retinal pigment epithelium (HRPE) cells is well recognized as the essential underlying mechanism responsible for the development of proliferative retinal diseases. In vitro, three-dimensional (3D) models associated with spontaneous O₂ gradients can be used to recapitulate the pathological levels of hypoxia to study the effect of hypoxia on the TGF-β2-induced EMT of HRPE cells in detail, we used two-dimensional-(2D) and 3D-cultured HRPE cells. TGF-β2 and hypoxia significantly and synergistically increased the barrier function of the 2D HRPE monolayers, as evidenced by TEER measurements, the downsizing and stiffening of the 3D HRPE spheroids and the mRNA expression of most of the ECM proteins. A real-time metabolic analysis indicated that TGF-β2 caused a decrease in the maximal capacity of mitochondrial oxidative phosphorylation in the 2D HRPE cells, whereas, in the case of 3D HRPE spheroids, TGF-β2 increased proton leakage. The findings reported herein indicate that the TGF-β2-induced EMT of both the 2D and 3D cultured HRPE cells were greatly modified by hypoxia, but during these EMT processes, the metabolic plasticity was different between 2D and 3D HRPE cells, suggesting that the mechanisms responsible for the EMT of the HRPE cells may be variable during their spatial spreading.     

A surfactant dispersed SWCNT-polystyrene composite characterized for electrical and mechanical properties

Single wall carbon nanotubes (SWCNTs) were dispersed in polystyrene (PS) at 0.1, 0.2, 0.3 and 1.0 wt.% (weight percent) concentrations using a surfactant assisted method. The resulting nanocomposites were characterized for their electrical conductivity, mechanical strength and fracture toughness properties. Results show a significant improvement in electrical conductivity with electrical percolation occurring by 0.2 wt.% SWCNT loading and the SWCNT-PS nanocomposite fully conductive at 1.0 wt.%. Three-point bend tests showed a decline in flexural strength and break strain with the addition of 0.1 wt.% SWCNTs. Improvements in the flexural modulus, strength and break strain with increasing SWCNT wt.% content followed The fracture toughness of the SWCNT-PS nanocomposites, in terms of the critical stress-intensity factor K_IC, was reduced relative to the neat material. From optical and high resolution scanning electron microscopy the presence of the carbon nanotubes is shown to have an adverse effect on the crazing mechanism in this PS material, resulting in a deterioration of the mechanical properties that depend on this mechanism.     

Simple photoreduction of graphene oxide nanosheet under mild conditions

Graphene oxide (GO) nanosheets were reduced by UV irradiation in H2 or N2 under mild conditions (at room temperature) without a photocatalyst. Photoreduction proceeded even in an aqueous suspension of nanosheets. The GO nanosheets reduced by this method were analyzed by X-ray photoelectron spectroscopy and Raman spectroscopy. It was found that epoxy groups attached to the interiors of aromatic domains of the GO nanosheet were destroyed during UV irradiation to form relatively large sp2 islands resulting in a high conductivity. I-V curves were measured by conductive atomic force microscopy (AFM; perpendicular to a single nanosheet) and a two-electrode system (parallel to the nanosheet). They revealed that photoreduced GO nanosheets have high conductivities, whereas nonreduced GO nanosheets are nearly insulating. Ag+ adsorbed on GO nanosheets promoted the photoreduction. This photoreduction method was very useful for photopatterning a conducting section of micrometer size on insulating GO. The developed photoreduction process based on a photoreaction will extend the applications of GO to many fields because it can be performed in mild conditions without a photocatalyst.