The effect of arsenic exposure on the biochemical and mineral contents of Labeo rohita bones: An FT-IR study

Arsenic compounds are ubiquitous and widespread in the environment as a result of natural or anthropogenic occurrence. Fish are the major source of protein for human consumption. They are also a source of contamination, because of the amounts of heavy elements they can contain, some of which are highly toxic. Fish bones are high in calcium, which is an essential mineral for normal body function. It consists of water, organic material, and mineral matter. Chelating agents have been used clinically as antidotes for acute and chronic metal intoxications. In the present study, an attempt is made to investigate the bio-accumulation of arsenic and its effect on the biochemical and mineral contents of Labeo rohita bones using, Fourier transform infrared (FT-IR) spectroscopy. The results of the present study indicate that arsenic exposure induces significant reduction on the biochemical and mineral contents of the L. rohita bones. Further, the DMSA treatment significantly improves these levels. This shows that DMSA is an effective chelator for arsenic toxicity. Quantitative curve-fitting analyses of amide I band have proved useful in studying the nature and the extent of protein conformational changes. A decrease in α-helical and random coil structures and an increase in β-sheet structures have been observed due to arsenic exposure. In conclusion, the present study shows that the FT-IR spectroscopy coupled with second derivative and curve-fitting analysis gives useful information about the biochemical and mineral contents of the L. rohita bones.     

Bioconcentration of zinc and its effect on the biochemical constituents of the gill tissues of Labeo rohita: An FT-IR study

In the present work, an attempt has been made to assess the bioconcentration and distribution of zinc on the selected organs of Labeo rohita and to study the effect of zinc exposure on the biochemical constitutions of gill tissues of L. rohita by using FT-IR Spectroscopy. The concentration pattern in the organs reveals that the liver is the prime site of metal binding and muscle accumulates least metal concentration. The accumulation profile is in the order: liver > gill > kidney > brain > bone > muscle. It has also been observed that the administration of chelating agent d-Penicillamine (DPA) reduces the zinc concentration in all tissues more effectively than the administration of the chelating agent Ethylene Diamine Tetra Acetic acid. The FT-IR spectra reveal that zinc exposure causes significant changes in the biochemical constitutions of the gill tissues. It causes an alteration in the protein secondary structures by decreasing the α-helix and increasing the β-sheet contents. Further, it has been observed that the administration of chelating agent DPA improves the protein and lipid contents in the gill tissues compared to zinc exposed tissues. This result shows that DPA is the effective chelator of zinc in reducing the body burden of L. rohita fingerlings. In conclusion, the findings of the current study suggest that zinc exposure causes significant changes in both lipids and proteins of the gill tissues, and changes the protein profile in favour of β-sheet structure.     

A FT-IR spectroscopic study of ultrasound effect on aqueous imidazole based ionic liquids having different counter ions

Ultrasound (US) effect on 1-butyl-3-methyl-imidazolium (BMI) ionic liquids having different counter anions, BF₄⁻, PF₆⁻ and Cl⁻ in aqueous medium was studied by FT-IR spectroscopy. Their deconvolution spectra were used to analyze the change of hydrogen bond in the absence and presence of US exposure to the ionic liquid. The FT-IR spectra were measured in different water contents without and with US at 23 kHz. These results indicated that the counter anion species in the imidazole based the ionic liquids played an important role for water solvation, when the US was exposed. The US hardly changed hydrogen bonding in the aqueous BMI–PF₆, while the BMI–BF₄ and BMI–Cl showed obvious change in their FT-IR spectra. Especially for the BMI–Cl, significant change was observed by the US exposure in the range of 2.6 wt% to 20 wt% of water contents. The results showed that the US could break the hydrogen bond in the BMI–Cl ionic liquids. In the case of BMI–BF₄, the FT-IR band at 950–1152 cm⁻¹ was significantly intensified under US exposure, due to that the US influenced BF₄⁻-water interaction. But, it was observed that the ionic liquid having PF₆⁻ was very less changed in the US system.     

FT-IR study of the acid sites on the surface of silica supported ruthenium oxide

FT-IR spectra of adsorbed CO, pyridine and acetone indicate that on the surface of RuO₂/SiO₂ are present Brønsted and Lewis acid sites and different reduced metal sites.     

FT-IR study of the surface properties of K2O-TiO2

K₂O-TiO₂ samples have been prepared by impregnation using KOH in water solution. The surface area decreases by increasing the loading, after calcination at 673 K. Samples containing about one K⁺ atom each 11 Ų reveal a complete modification of the titania surface, attributed to the formation of a “surface-K₂O-phase”. Such a surface presents, after activation, coordinatively unsaturated K⁺ cations that act as weak Lewis acid sites and are also able to interact with hydrocarbons such as propylene and basic sites where ammonia is hydrogen-bonded and water and formic acid are dissociated. Neither ammonia nor propylene dissociate to a detectable extent at room temperature on K₂O-TiO₂. Surface hydroxy groups are also observed, having a low acidic character.     

FTIR study of zinc-induced biochemical changes in the liver of Indian carp <Emphasis Type="Italic">Labeo rohita</Emphasis>

Zinc is an essential metal for different physiological functions and becomes toxic when elevated concentrations are introduced into the environment. In the present study, an attempt is made to analyze zinc-induced biochemical changes in the liver tissues of freshwater fingerlings of Labeo rohita using Fourier Transformation Infrared Spectroscopy. Several important features have been observed in the FTIR spectra of zinc-intoxicated liver tissues, namely, altered membrane lipid, altered protein profile, and increased glycogen content, indicating an alteration in the lipid and protein profiles leading to modification in membrane composition. Further, it is observed that acute exposure to zinc causes some alteration in protein profile with a decrease in α-helix and an increase in random coil structure. Treatment with the chelating agent D-penicillamine reduces the biochemical contents in the liver tissues. This shows that D-penicillamine is a good antidote for zinc toxicity. Published in Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 5, pp. 746–752, September–October, 2008.     

Temperature effect on water desorption from methylcellulose films studied by thermal FT-IR microspectroscopy

Temperature-induced desorption behavior of water from methylcellulose (MC) film was investigated by a novel microscopic Fourier transform infrared (FT-IR) spectroscopy equipped with thermal analyzer (thermal FT-IR microscopic system) and thermogravimetric analysis (TGA). The result indicates that the weight loss of water from MC film was markedly correlated to the IR spectral changes of OH stretching (3000-3800 cm⁻¹) and bending (1649 cm⁻¹) modes of water molecules. The shift of OH stretching mode from 3461 to 3481 cm⁻¹ was accompanied with the water loss from MC film induced by temperature effect. Two stages of water desorption from MC film were proposed: the first stage within the 35-65 °C had a dramatic IR peak shift from 3461 to 3477 cm⁻¹ and accompanied with a largest weight loss of water from MC film, which might be mainly due to the desorption of free water with minor weakly hydrogen-bonded water; the second stage beyond 65 °C would be desorption of moderately hydrogen-bonded bound water, due to the gradual IR spectral shift from 3477 to 3481 cm⁻¹ and a slower weight loss of water from MC film. The changes in peak area ratio of 1649 cm⁻¹/1374 cm⁻¹ with the temperature also confirmed the IR spectral peak shift of the OH stretching mode via the water loss from MC film. The temperature-dependent dissociation of intermolecular and intramolecular hydrogen bonds within water molecules and/or between water/MC interaction might be responsible for the desorption kinetics of water from MC film.     

Diagnostic study of the roughness surface effect of zirconium on the third-order nonlinear-optical properties of thin films based on zinc oxide nanomaterials

Zinc oxide (ZnO) and zirconium doped zinc oxide (ZnO:Zr) thin films were deposited by reactive chemical pulverization spray pyrolysis technique on heated glass substrates at 500 °C using zinc and zirconium chlorides as precursors. Effects of zirconium doping agent and surface roughness on the nonlinear optical properties were investigated in detail using atomic force microscopy (AFM) and third harmonic generation (THG) technique. The best value of nonlinear optical susceptibility χ⁽³⁾ was obtained from the doped films with less roughness. A strong third order nonlinear optical susceptibility χ⁽³⁾ = 20.12 × 10⁻¹² (esu) of the studied films was found for the 3% doped sample.     

The effect of microsegregation on the generation of dislocations in zinc single crystals

The applicability of Tiller's considerations on the production of dislocations is proved. The density of dislocations appearing during impurity microsegregation increases with increasing rate of growth as a consequence of the corresponding change in the effective distribution coefficient. The real value of C at the microsegregation boundaries is at least twice as great as the average value of the concentration of impurities in the crystal in question.

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研磨影响粘土结构的红外光谱研究

将高岭石和蒙石两种粘土矿物分别用干法和湿法连续研磨,通过不同研磨时间的各粉城叶变换红外光谱（ＦＴ－ＩＲ）的实测和比较,发现干法研１２ｈ高岭石和蒙脱古老珠结构均开发改变,经４２ｈ高岭石的层状结构完全破坏,而经２４ｈ蒙脱石的层状结构即被破坏,但在湿法条件下研磨５４ｈ,它们的结构均无明显变化。由此可见,湿法研磨比干法好,文中还初步探讨了研磨影响粘土结构的原因。     

The effect of accelerator contents on the vulcanizate structures of SSBR/silica vulcanizates

Physical properties of rubber compounds are affected by the filler–rubber interaction, filler dispersion in the rubber matrix, and cross-link structure formed during vulcanization. In particular, the cross-link structure is closely related to the physical properties of vulcanizates and has been analyzed using the swelling test and Flory-Rehner equation. However, the relationship between the structure and physical properties of vulcanizates cannot be explained by the cross-link density obtained using these methods. The cross-link density obtained from the swelling test is a complex result of the filler–rubber interaction occurring during the compounding as well as the chemical cross-link structure formed by sulfur during the vulcanization. Moreover, the rubber vulcanizates that use silica need to be separately analyzed for each factor as its physical properties are affected more by the filler–rubber interaction than by carbon black. Therefore, this study determines the factors that contribute to the total cross-link density of vulcanizates into chemical cross-link density and filler–rubber interaction via quantitative analysis using the swelling test results and Flory-Rehner and Kraus equations. The vulcanizates used for the analysis were carbon black-filled and silica-filled non-functionalized SSBR compounds with varying cure accelerator for each filler loading. Their chemical cross-link density was measured and the effect of the filler–rubber interactions on their mechanical and dynamic viscoelastic properties was investigated. Furthermore, the relationship between the structure and physical properties of rubber vulcanizates was elucidated.     

铼配合物光异构化的拉曼和红外光谱研究

光敏分子和它们在光作用下发生的异构化一直是分子光化学研究领域中感光趣的课题。含有光敏基团的铼配合物的一个新颖特性是其具有电致发光性质。为弄清结构与功能性质的联系 ,本文研究了 Re(CO) 3 (2 ,2 '-联吡啶 ) [4- (4'-硝基苯己烯基吡啶 ) ]高氯酸盐的 FT-Raman和 FT- IR光谱 ,指认了光照前和光照后的拉曼位移。讨论了这些变化与金属到配体电荷转移的联系     

The effect of oxygen exposure on pentacene electronic structure

We use ultraviolet photoelectron spectroscopy to investigate the effect of oxygen and air exposure on the electronic structure of pentacene single crystals and thin films. It is found that O₂ and water do not react noticeably with pentacene, whereas singlet oxygen/ozone readily oxidize the organic compound. Also, we obtain no evidence for considerable p-type doping of pentacene by O₂ at low pressure. However, oxygen exposure lowers the hole injection barrier at the interface between Au and pentacene by 0.25 eV, presumably due to a modification of the Au surface properties.     

On the decay of the polarization charge on zinc oxide induced by the pyroelectric effect

Using a method which was mainly developed to measure surface charges on insulators, the decay of pyroelectrically induced polarization charges on zinc oxide was studied. If no charge carriers were injected into the crystal, the decay of the charge was found to obey a logarithmic time law. Since field dependent processes could be ruled out to cause the decay, this law is indicative for processes, the thermal activation energies of which are continuously distributed.     

Duration of whole-body vibration exposure its effect on comfort

Most human response to vibration standards imply that low vibration levels are acceptable for longer periods than higher levels. In such standards it is usually assumed that the relationship between exposure duration and vibration level is of a similar form for a wide range of different types of motion. The experiment described in this paper was conducted to determine whether the relative discomfort produced by 4 Hz and 16 Hz sinusoidal whole-body vertical (a_z) vibration was dependent on the duration of the vibration exposure.Each of eight seated subjects was exposed to two 36-minute vibration sessions. Both sessions consisted of ten-second periods of 4 Hz and 16 Hz vibration alternating continuously. In one session the 4 Hz motion was set at the “standard” level of 0·75 m/s² r.m.s. while the level of the 46 Hz “test” motion could be adjusted by the subjects. In the other session the 16 Hz motion was the standard at 0·75 m/sl r.m.s. and the level of the 4 Hz motion could be adjusted. The subjects were required to control the intensity of the test motion to compensate for periodic changes in its intensity made by the experimenter and so to maintain it at a level which produced similar discomfort to that caused by the standard motion.It was found that the relationship between the average levels of the two motions when adjusted to produce similar discomfort was independent of the vibration duration. The findings are discussed in relation to other laboratory research and the need for a better understanding of the effects of the duration of a vibration on its acceptability.     

On the effect of impurities on the critical resolved shear stress of zinc single crystals

The dependence of the critical resolved shear stress of zinc single crystals on the impurity content and the dislocation density is observed. It is shown that the effect of impurities on the critical resolved shear stress is indirect.

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Ultrastructural and biochemical changes of the medial pterygoid muscle induced by unilateral exodontia

The aim of the present study was to investigate the histological, biochemical and ultrastructural effects of occlusal alteration induced by unilateral exodontia on medial pterygoid muscle in guinea pigs, Cavia porcellus. Thirty (n=30) male guinea pigs (450g) were divided into two groups: experimental-animals submitted to exodontia of the left upper molars, and sham-operated were used as control. The duration of the experimental period was 60 days. Medial pterygoid muscles from ipsilateral and contralateral side were analyzed by histological (n=10), histochemical (n=10), and ultrastructural (n=10) methods. The data were submitted to statistical analysis. When the ipsilateral side was compared to the control group, it showed a significantly shorter neuromuscular spindle length (P<0.05), lower oxidative metabolic activity, and microvessel constriction, in spite of the capillary volume and surface density were not significantly different (P>0.05). In the contralateral side, the neuromuscular spindles showed significantly shorter length (P<0.05), the fibers reflected a higher oxidative capacity, the blood capillaries showed endothelial cell emitting slender sprouting along the pre-existing capillary, and significantly higher blood capillary surface density, and volume density (V(v)=89% Mann-Whitney test, P<0.05). This finding indicated a complex morphological and functional medial pterygoid muscle adaptation to occlusal alteration in this experimental model. Considering that neuromuscular spindles are responsible for the control of mandibular positioning and movements, the professional should consider if these changes interfere in the success of clinical procedures in medical field involving stomatognathic structures.