The role of nano colloid of TiO2 and butane tetra carboxylic acid on the alkali solubility and hydrophilicity of proteinous fibers

One of the main problems of wool as an important proteinous fiber is low resistance against alkali media. Finding a way to solve this problem without any influences on other fiber characteristics is still a matter of research. Using nano particles on textile materials is a new approach to produce novel properties. Here, nano titanium dioxide (NTO) particles along with butane tetra carboxylic acid (BTCA) were sonicated in the ultra sound bath and applied as a nano colloid on the wool fabric. BTCA played different roles as wool cross-linker, a polyanionic agent, and stabilizer for nano TiO2. Various concentrations of NTO and BTCA were applied through impregnation of the fabric in ultrasonic bath followed by curing. The resistance of fabrics against alkali was assessed by solubility in sodium hydroxide and the hydrophilicity monitored by the water drop absorption time and the contact angle before and after UV irradiation. Interestingly, the alkali solubility of the nano TiO2 treated wool fabrics reduced while the fabric became more hydrophilic. This fact was shown by the testing results and is thoroughly discussed in the article. The response surface methodology (RSM) was also applied to find the optimum conditions for the wool fabric treatment.

Enhanced photocatalytic activities of TiO2-SiO2 nanohybrids immobilized on cement-based materials for dye degradation

Using cement-based material as a matrix for photocatalytic hybrids is an important development for the large-scale application of photocatalytic technologies. In this work, photocatalytic activity of nanosized hybrids of TiO2/SiO2 (nano-TiO2-SiO2) for degradation of some organic dyes on cementitious materials was highlighted. For this purpose, an optimal inorganic sol-gel precursor was firstly applied to prepare the composites of nano-TiO2-SiO2 which was characterized by XRD, SEM and UV-Vis. Then, a thin layer was successfully coated on white Portland cement (WPC) blocks using a dipping process in a nano-TiO2-SiO2 solution. The effect of nano-TiO2-SiO2-coated WPC blocks on photocatalytic decomposition of three dyes, including Malachite green oxalate (MG), Methylene blue (MB) and Methyl orange (MO) were studied under UV irradiation and monitored by chemical oxygen demand tests. The results showed an increase in photocatalytic effects which depends on the structure and pH of the applied cement.

UV induces resistance in Arabidopsis Thaliana to the Oomycete Pathogen Hyaloperonospora Parasitica

Owing to their sessile nature, plants have evolved mechanisms to minimise the damaging effects of abiotic and biotic stresses. Attack by pathogenic fungi, viruses and bacterium is a major type of biotic stress. To resist infection, plants recognise invading pathogens and induce disease resistance through multiple signal transduction pathways. In addition, appropriate stimulation can cause plants to increase their resistance to future pathogen attack. We have found that exposure to non-lethal doses of UV-C (254 nm) renders a normally susceptible ecotype of Arabidopsis thaliana resistant to the biotrophic Oomycete pathogen Hyaloperonospora parasitica. The UV treatment induces an incompatible response in a dose-dependent fashion, and is still effective upon pathogen inoculation up to seven days after UV exposure. The degree of resistance diminishes with time but higher doses result in greater levels of resistance, even after seven days. Furthermore, the effect is systemic, occurring in parts of the plant that have not been irradiated. Incubation in the dark post?irradiation and prior to infection reduces the UV dose required to generate a specific level of pathogen resistance without affecting the duration of resistance. These observations, plus the inability of plants to photoreactivate UV photoproducts in the dark, strongly suggest that DNA damage induces the resistance phenotype. Currently, we are assessing the influence of DNA repair defects on UV-induced resistance, following the expression of a number of defence?related genes post-UV-C irradiation, and assessing the effect of UV in plant mutants deficient in specific signalling molecules involved in resistance.

Photocatalytic degradation of phenanthrene on soil surfaces in the presence of nanometer anatase TiO2 under UV-light

The effect of nanometer anatase TiO2 was investigated on the photocatalytic degradation of phenanthrene on soil surfaces under a variety of conditions. After being spiked with phenanthrene, soil samples loaded with different amounts of TiO2 (0 wt.%, 1 wt.%, 2 wt.%, 3 wt.%, and 4 wt.%) were exposed to UV-light irradiation for 25 hr. The results indicated that the photocatalytic degradation of phenanthrene followed the pseudo first-order kinetics. TiO2 significantly accelerated the degradation of phenanthrene with the half-life reduced from 45.90 to 31.36 hr for TiO2 loading of 0 wt.% and 4 wt.%, respectively. In addition, the effects of H2O2, light intensity and humic acid on the degradation of phenanthrene were investigated. The degradation of phenanthrene increased with the concentration of H2O2, light intensity and the concentration of humic acids. It has been demonstrated that the photocatalytic method in the presence of nanometer anatase TiO2 was a very promising technology for the treatments of soil polluted with organic substances in the future.

Sub-lethal UV-C radiation induces callose, hydrogen peroxide and defence-related gene expression in Arabidopsis thaliana

Exposure of plants to UV-C irradiation induces gene expression and cellular responses that are commonly associated with wounding and pathogen defence, and in some cases can lead to increased resistance against pathogen infection. We examined, at a physiological, molecular and biochemical level, the effects of and responses to, sub-lethal UV-C exposure on Arabidopsis plants when irradiated with increasing dosages of UV-C radiation. Following UV-C exposure plants had reduced leaf areas over time, with the severity of reduction increasing with dosage. Severe morphological changes that included leaf glazing, bronzing and curling were found to occur in plants treated with the 1000 J·m(-2) dosage. Extensive damage to the mesophyll was observed, and cell death occurred in both a dosage- and time-dependent manner. Analysis of H2 O2 activity and the pathogen defence marker genes PR1 and PDF1.2 demonstrated induction of these defence-related responses at each UV-C dosage tested. Interestingly, in response to UV-C irradiation the production of callose (β-1,3-glucan) was identified at all dosages examined. Together, these results show plant responses to UV-C irradiation at much lower doses than have previously been reported, and that there is potential for the use of UV-C as an inducer of plant defence.