In June 2008, a surveillance study for metals in honeybees was performed in the Netherlands. Randomly, 150 apiaries were selected. In each apiary, five colonies were sampled. Per apiary, the hive samples were pooled. The apiary sample was analysed for Al, As, Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Sb, Se, Sn, Sr, Ti, V and Zn. All metals could be detected in all apiaries. As, Li, Sb, Sn and V were...

BACKGROUND Apical extrusion of debris during instrumentation is detrimental to the patient. AIM The aim of this study was to evaluate the apical extrusion of debris during root canal instrumentation using two single file rotary Ni-Ti systems. MATERIALS AND METHODS Thirty freshly extracted mandibular premolars with straight roots were sterilized and divided into two groups instrumented using...

In the present study, structural characterization of NiTi smart shape memory alloys (SMAs), produced by an alternative powder metallurgy approach named mechanically activated reactive forging (MARFOS), was carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was observed that MARFOS materials had a multiphase nanocrys...

Context. The chemical analysis of secondary stars of low mass X-ray binaries provides an opportunity to study the formation processes of compact objects, either black holes or neutron stars. Aims. Following the discovery of overabundances of α-elements in the Keck I/HIRES spectrum of the secondary star of Nova Scorpii 1994 (Israelian et al. 1999), we obtained VLT/UVES high-resolution spectrosco...

Purpose To evaluate the retinal vessel oxygen saturation in central serous chorioretinopathy (CSC) cases among the Chinese. Methods Relative oxygen saturation of retinal blood vessels was measured in 33 Chinese patients with single-eye CSC using the Oxymap T1 retinal oximeter. The contralateral eyes were the control. The mean saturation of the retinal arteriole (AS) and venule (VS), arteriove...

AIM To develop an accurate finite element (FE) model for studying rotary endodontic instruments and to demonstrate the usefulness of the FE method in improving the knowledge of the mechanical behaviour of these instruments during root canal preparation. METHODOLOGY An accurate geometrical model of a Ni-Ti ProTaper F1 instrument was created. The interaction between the rotating instrument and ...

Safety and reliability are crucial issues for medical instruments and implants. In the past few decays, bulk metallic glasses (BMGs) have drawn attentions due to their superior mechanical properties, good corrosion resistance, antibacterial and good biocompatibility. However, most Zr-based and Ti-based BMGs contain Ni as an important element which is prone to human allergy problem. In this stud...

BACKGROUND Different environmental conditions, such as high temperature or exposure to some chemical agents, may affect the force decay of different methods of space closure during orthodontic treatment. The aim of this in vitro study was to evaluate the force decay pattern in the presence of tea as a popular drink in some parts of the world and two mouthwashes that are usually prescribed by th...

The objective of this study was to evaluate the effects of metal ions, which may be released from orthopedic or dental implants, on osteoblast metabolism and differentiation. ROS 17/2.8 cells were cultured in F-12 medium for 7 days. Then Al+3, Co+2, Cr+3, Ni+2, Ti+4, and V+3 were added at concentrations less than their cytotoxic concentrations. After 3 days, DNA synthesis, succinate dehydrogena...