The aim of this study was to investigate the possibility of detecting root canal constrictions by using an apex locator. Seventy impenetrable canals in extracted human teeth were used. Based on contact microradiographic findings, they were divided into three groups: group A (constricted within 3 mm of the radiographic apex, 23 canals), group B (nonconstricted within 3 mm of the radiographic ape...

Root canal impedance measurement was carried out in vivo on a series of patients and in vitro on a model (tooth dipped into a saline solution). Impedance was measured for several file tip displacements from apical foramen in the frequency range from 100 Hz to 1 MHz. Comparison between in vivo and in vitro results was performed for the measured value of impedance and for the components (Rp, Cp) ...

BACKGROUND In unaided caudal epidural block (CEB), incorrect needle insertion has been reported to occur in 15% to 38% of attempts. OBJECTIVE To statistically analyze the anatomical variables affecting difficult CEB using ultrasonographic measurement. METHODS Preprocedural ultrasonography was performed and the following measurements were obtained in 146 patients: the distance from the skin ...

BACKGROUND The pedicle screw placement in scoliosis correction at the apex underlies potential risk for neurological injury. This research is to investigate the relative position of spinal cord at the apex in idiopathic thoracic scoliosis and to explore the risk of spinal cord injury from pedicle screw at the apex. METHODS Thirty-three adolescents with thoracic scoliosis were recruited in thi...

Many nanofabrication methods based on scanning probe microscopy have been developed during the last decades. Local anodic oxidation (LAO) is one of such methods: Upon application of an electric field between tip and surface under ambient conditions, oxide patterning with nanometer-scale resolution can be performed with good control of dimensions and placement. LAO through the non-contact mode o...

A practical experimental strategy is proposed that could potentially enable greater control of the tip apex in non-contact atomic force microscopy experiments. It is based on a preparation of a structure of interest alongside a reference surface reconstruction on the same sample. Our proposed strategy is as follows. Spectroscopy measurements are first performed on the reference surface to ident...

Pollen tube growth is a polarized growth process whereby the tip-growing tubes elongate within the female reproductive tissues to deliver sperm cells to the ovules for fertilization. Efficient and regulated membrane trafficking activity incorporates membrane and deposits cell wall molecules at the tube apex and is believed to underlie rapid and focused growth at the pollen tube tip. Rab GTPases...

We have used propidium iodide (PI) to investigate the dynamic properties of the primary cell wall at the apex of Arabidopsis (Arabidopsis thaliana) root hairs and pollen tubes and in lily (Lilium formosanum) pollen tubes. Our results show that in root hairs, as in pollen tubes, oscillatory peaks in PI fluorescence precede growth rate oscillations. Pectin forms the primary component of the cell ...