The cerium oxide nanoparticles toxicity induced physiological, histological and biochemical alterations in freshwater mussels, Unio crassus.

INTRODUCTION: Releasing of cerium oxide nanoparticles (nano-CeO2) to the nature has increased due to the widespread use in many fields ranging from cosmetics to the food industry. Therefore, nano-CeO2 has been included in the Organization for Economic Co-operation and Development's (OECD) priority list for engineering nanomaterials. In this study, the effects of nano-CeO2 on the freshwater mussels were investigated to reveal the impact on the freshwater systems on model organism. METHODS: First, the chemical and structural properties of nano-CeO2 were characterized in details. Second, the freshwater mussels were exposed to environmentally relevant concentrations of nano-CeO2 as 10 mg, 25 mg and 50 mg/L during 48-h and 7-d. Third, after the exposure periods, hemolymph and tissue samples were taken to analyse the Total Hemocyte Counts (THCs) histology and oxidative stress parameters (total antioxidant status, glutathione, glutathione-S-transferase, and advanced oxidative protein products). RESULTS: Significant decrease of the THCs was observed in the nano-CeO2 exposed mussels compared to the control group (P < 0.05). The histological results showed a positive association between nano-CeO2 exposure concentration in the water and level of tissue damage and histopathological alterations were detected in the gill and the digestive gland tissues. Oxidative stress parameters were slightly affected after exposure to nano-CeO2 (P > 0.05). In conclusion, this study showed that acute exposure of freshwater mussels to nano-CeO2 did not pose significant biological risk. However, it has been proven that mussels are able to accumulate nano-CeO2 significantly in their bodies. CONCLUSION: This suggests that nano-CeO2 may be a potential risk to other organisms in the ecosystem through trophic transfer in the food-web based on their habitat and niche in the ecosystem.

Clinicopathological diagnosis of orofacial granulomatosis.

Orofacial granulomatosis is a rare chronic inflammatory disorder characterized by persistent or recurrent soft tissue swellings, oral ulceration, and other orofacial features in the absence of an identifiable granulomatous disease. We report a case of a 61-year-old woman with recurrent ulcerations and swellings in her oral mucosa. She was diagnosed as orofacial granulomatosis based upon clinicopathological correlation after exclusion of other granulomatous diseases and showed a favorable response to systemic corticosteroid treatment.

Arteriovenous malformations in the differential diagnosis of palatal swellings.

An arteriovenous malformation (AVM) is composed of abnormal communications between arteries and veins without the normal intervening capillary bed. AVM of the head and neck is a rare vascular anomaly. We present here an unusual case of AVM with the size of 4x3 cm at the left posterior palatal area. Incisionel biopsy revealed AVM. Resection of the lesion following angiography was suggested to the patient however, he refused the treatment. The patient was considered to be under control. AVM should always be kept in mind in the differential diagnosis of palatal swellings.

Eosinophilic granuloma: resolution of lesion after biopsy.

Langerhans cell histiocytosis is a collective term used to describe a group of enigmatic proliferative disorders. Three disease variants include eosinophilic granuloma, Letterer-Siwe disease, and Hand-Schuller-Christian syndrome. Eosinophilic granuloma is reported to be the most benign type of the triad. In this report, a 7-year-old child with an eosinophilic granuloma of the left side of her mandible is presented. There was a painless, hard, tender mass arising from the left side of the molar region. Panoramic radiographs showed a radiolucent area at the molar region. The lesion was resolved 2 weeks after the biopsy. The 1.5 years of radiographic and clinical follow-up was satisfactory.

From heterogeneous to homogeneous nucleation of isotactic poly(propylene) confined to nanoporous alumina.

The crystallization of highly isotactic polypropylene confined in self-ordered nanoporous alumina is studied by differential scanning calorimetry. A transformation from a predominantly heterogeneous to predominantly homogeneous nucleation takes place if the pore diameter is smaller than 65 nm. Crystallization is suppressed with decreasing pore size, and the absence of nucleation below 20 nm pores indicates the critical nucleus size. The results reported here might enhance the understanding of nanocomposites containing semicrystalline polymers and reveal design criteria for polymeric nanofibers with tailored mechanical and optical properties.

High-vacuum vapor deposition and in situ monitoring of N-carboxy anhydride benzyl glutamate polymerization.

A high-vacuum physical vapor deposition (PVD) method was used to grow polypeptide chains from gold surfaces coupled with in situ monitoring using surface plasmon resonance spectroscopy (SPR). Polymerization of N-carboxy anhydride of benzyl-L-glutamate (BLG-NCA) was demonstrated, forming grafted polybenzyl-L-glutamate (PBLG) films. 2-Aminoethanethiol (AET) was used as the initiating site either deposited as a self-assembled monolayer (SAM), as a PVD film, or codeposited on the gold substrates. PBLG films up to 30 nm thick in which the formation of different secondary structures was monitored by in situ SPR and ex situ Fourier transform infrared spectroscopy (FT-IR) methods based on the parameters for deposition were prepared. Furthermore, surface topology and film morphology properties were determined on the basis of AFM measurements and were found to depend largely on the deposition process of the AET. Besides investigation of the AET surface density effects, the orientation of the PBLG chains was also characterized using ex situ FT-IR.

In situ characterization of N-carboxy anhydride polymerization in nanoporous anodic alumina.

Poly(gamma-benzyl-L-glutamate) (PBLG) has been a popular model polypeptide for a range of physicochemical studies, and its modifiable ester side chains make it an attractive platform for various potential applications. Thin films of Poly(gamma-benzyl-L-glutamate) PBLG were surface grafted within nanoporous anodic alumina (AAO) by surface-initiated polymerization of the N-carboxy anhydride of benzyl-L-glutamate (BLG-NCA). The grafting process was characterized by optical waveguide spectroscopy (OWS), infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). OWS was able to track the PBLG layer thickness increase in situ, and ex situ FT-IR gave complementary information on the PBLG chain's secondary structure. Transitions in the PBLG growth rate could be correlated with transitions in the polypeptide secondary structure. The emergence of a three-dimensional, anisotropic PBLG morphology within the cylindrical pores of the AAO membrane was also identified as the grafted PBLG average layer thickness increased. Comparison of the PBLG/AAO results with those on a planar silicon dioxide surface indicated that both the conformational transitions and the PBLG nanostructure development could be attributed to the confining geometry within the pores of the nanoporous AAO matrix. The use of a nanoporous AAO matrix, combined with the surface grafting of a thin film of PBLG chains with multiple modifiable side chains, could potentially offer a nanoporous platform with a very high density of functional sites.