Raman spectroscopic investigation on the microenvironment of the liver tissues of Zebrafish (Danio rerio) due to titanium dioxide exposure

Nano titanium dioxide (nTiO₂), generally considered to be toxicologically inert, is manufactured in large quantities and extensively applied in consumer products. The small size and large surface area endow them with an active group or intrinsic toxicity. Advances in instrumentation are making Raman spectroscopy the tool of choice for an increasing number of (bio) chemical applications. One of the great advantages of this technique is its ability to provide information on the concentration, structure and interaction of biochemical molecules in their microenvironments within intact cells and tissues, non-destructively. Zebrafish (Danio rerio), one of the most important vertebrate model organisms used in developmental biology, are increasingly used in biomedical research, particularly as a model of human disease. In the present work, an attempt is made to study the effect of titanium dioxide, both nano and bulk, on the microenvironment of the liver tissues of Zebrafish using FT-Raman spectroscopy. The results of the present study suggest that TiO₂ exposure demonstrate a marked influence on the microenvironments of the liver tissues of Zebrafish. A shift to a higher wavenumber and an increase in the intensity of the band at ∼1087 cm⁻¹ in the TiO₂ exposed tissues suggest that some of the conformational changes resulting from the alkali recovery process takes place due to TiO₂ exposure. The decreased intensity ratio (I₃₂₂₀/I₃₄₀₀) observed in the titanium-exposed tissues suggests a decreased water domain size, which could be interpreted in terms of weaker hydrogen-bonded molecular species of water in the TiO₂ exposed tissues. The observed shift of COO⁻ bands to higher frequencies shows the disruption of salt bridges as a result of a change in the oppositely charged partners and due to the enhanced random coil conformation. The variation in the intensity ratio of the tyrosyl doublet (I₈₅₈/I₈₂₅) indicates variation in the hydrogen bonding of the phenolic hydroxyl group due to TiO₂ exposure. The results further suggest that the microenvironments are greatly altered due to titanium nano exposure when compared to titanium bulk. In conclusion, the results indicate that FT-Raman spectroscopy might be a useful tool for rapid assessment of nano particle biological interactions.     

The study of the changes in the thermal properties of <Emphasis Type="Italic">Labeo rohita</Emphasis> bones due to arsenic exposure

The paper presents the changes in the thermal properties of control, arsenic exposed and DMSA treated Labeo rohita bones by using thermo analytical techniques. The result shows that the mass loss due to the thermal decomposition occurs in three distinct steps due to loss of water, organic and inorganic materials. The arsenic exposed bones present a different thermal behaviour compared to the control bones. The residue masses are increased due to arsenic exposure, while the DMSA treatment reduces the residue mass level. These thermal characteristics can be used as a qualitative method to check the metal accumulation in samples.     

Comparison between the conventional method of extraction of essential oil of Laurus nobilis L. and a novel method which uses microwaves applied in situ, without resorting to an oven

A novel microwave method has been applied to the hydrothermal extraction of essential oil from plants. An insulated microwave coaxial antenna was introduced inside a 1000 ml glass flask containing dry Laurus nobilis L. leaves and tap water. Microwave power up to 800 W at 2450 MHz was emitted in continuous wave regime (CW) or in pulsed regime (PR) at 8 kW peak power. Stirring with a magnetic bar and a Clevenger refrigerator connected to the flask enabled to complete the extraction in 1 h. The results of the in situ microwave extraction were compared with those obtained by heating the same reactor with a conventional electric mantle by gas chromatography-mass spectrometry (GC-MS) analysis. Differences were observed both in the composition of the essential oil and from the energetic point of view. The essential oil obtained with microwave (MW) methods contained substantially higher amounts of oxygenated compounds and lower amounts of monoterpenes than conventional method. The in situ microwave heating is safe and versatile; it presents time and energy saving advantages, and therefore it can be considered useful also for industrial applications.     

Use of solid-phase micro-extraction as a sampling technique in the determination of volatiles emitted by flowers,isolated flower parts and pollen

The volatiles emitted by fresh whole flowers or isolated flower parts of mandarin, Citrus deliciosa Ten. (Rutaceae), were sampled using solid-phase micro-extraction (SPME). This technique offers several advantages over dynamic headspace sampling techniques used in previous investigations. In particular, SPME requires smaller sample sizes and very short sampling times, which can minimize the formation of artifacts due to damage to the plant, and contaminations or loss of compounds. This was especially applicable to the collection of volatiles from pollen.     

On the system of functional equationsf(x + y) = f(x) + f(y) andf(xy) = p (x)f(y) + q(y)f(x)

Aequationes mathematicae -     

Some relations between additive functions,II

Aequationes mathematicae -     

Spectral and scattering theory for a Schrödinger operator with a class of momentum-dependent long-range potentials

Let be the selfadjoint operator for the static electromagnetic field where W _j for 0, 1, 2, ..., n is a sum of (i) a short-range potential and (ii) a smooth long-range potential decreasing at as |x|^- with in (0, 1]. Then for >1/2, asymptotic completeness holds for the scattering system (H, H ₀).