Publications by authors named "Malek O"

Nanocelluloses are emerging as natural materials with favourable properties for coating industry and can be applied by state-of-the-art spraying technology. While additional functionalities are commonly introduced through chemical modification, the surface microstructuring of nanocellulose coatings with high throughput methods remains unexplored. Here, a femtosecond laser is used for texturing spray-coated coatings made of cellulose nanofibrils (CNF) or cellulose nanocrystals (CNC).

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Ultrafast laser processing of zirconia/alumina nanocomposite ceramics, the current gold standard material for ceramic bearing components in orthopedics, was investigated. Instead of considering the substrate as a homogeneous material, as commonly assumed in laser micromachining, the damage behavior of different phases around the laser ablation threshold upon ultrafast laser irradiation was investigated. Under appropriate experimental conditions, the zirconia phase was selectively ablated while the alumina phase remained intact.

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Background: Micronutrient deficiencies (MNDs) are a chronic lack of vitamins and minerals and constitute a huge public health problem. MNDs have severe health consequences and are particularly harmful during early childhood due to their impact on the physical and cognitive development. We estimate the costs of illness due to iron deficiency (IDA), vitamin A deficiency (VAD) and zinc deficiency (ZnD) in 2 age groups (6-23 and 24-59 months) of Filipino children by socio-economic strata in 2008.

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Partial and some few cases of complete spontaneous regression have been observed in cutaneous melanoma patients but little is known about the molecular mechanisms involved. The Melanoblastoma-bearing Libechov Minipig (MeLiM) is a suitable animal model to study the phenomenon of spontaneous regression because MeLiM pigs exhibit naturally occurring melanomas which regress completely 6 months after birth. In this study, we used suppression subtractive hybridization (SSH) to identify molecular determinants of melanoma regression within swine melanoma tissues and melanoma cell cultures.

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Sarcoma is a relatively rare malignant disease with high mortality, bad prognosis and response to conventional therapy. Two possible models of this disease were tested: the K2 rat sarcoma cell line, which was described previously, and the new rat R5-28 cell line derived from a spontaneously growing rat neoplasm with sarcoma morphology. While all rats inoculated with K2 cells developed tumours at 22th-25th day after inoculation (D = 22-25), only 60%-75% of R5-28-inoculated rats were affected by tumours.

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Frzb-1 is a secreted protein, presenting similarity with the Wnt-binding domain of the frizzled family of receptors, which acts as an antagonist of Wnt signaling. Using mRNA differential display in the rat aorta balloon injury model, we identified overexpression of Frzb-1 mRNA and determined its cDNA sequence. By quantitative reverse transcription-polymerase chain reaction and RNase protection assay, a biphasic upregulation of rFrzb-1 expression was observed, with significant peaks of a 1.

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RNA editing affects messenger RNAs and transfer RNAs in plant mitochondria by site-specific exchange of cytidine and uridine bases in both seed and nonseed plants. Distribution of the phenomenon among bryophytes has been unclear since RNA editing has been detected in some but not all liverworts and mosses. A more detailed understanding of RNA editing in plants required extended data sets for taxa and sequences investigated.

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The fragmentation of group II introns without concomitant loss of splicing competence is illustrated by extraordinary gene arrangements in plant mitochondrial genomes. The mitochondrial genes nad1, nad2, and nad5, all encoding subunits of the NADH dehydrogenase, require trans-splicing for functional assembly of their mRNAs in flowering plants. Tracing the origins of trans-splicing group II introns shows that they have evolved from formerly cis-arranged homologs whose descendants can still be identified in lineages of early branching land plants.

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Trans-splicing in angiosperm plant mitochondria connects exons from independent RNA molecules by means of group II intron fragments. Homologues of trans-splicing introns in the angiosperm mitochondrial nad2 and nad5 genes are now identified as uninterrupted group II introns in the ferns Asplenium nidus and Marsilea drummondii. These fern introns are correctly spliced from the pre-mRNA at the sites predicted from their well-conserved secondary structures.

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The Magnoliaceae are discussed as one of the key species at the root of the flowering plants. To obtain molecular information for one of these phylogenetically interesting plant species, we determined genomic and cDNA sequences of the mitochondrial cox3 gene in Magnolia grandiflora. Twenty-two RNA editing events are identified to alter cytidines in the mRNA to uridines, all but one of which change the encoded amino acid identity.

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RNA editing has been observed to date in all groups of vascular plants, but not in bryophytes. Its occurrence was therefore assumed to correlate with the evolution of tracheophytes. To gain more insight into both the phylogeny of early land plants and the evolution of mitochondrial RNA editing we have investigated a number of vascular and non-vascular plant species.

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