In growing Arabidopsis root hairs, the nucleus locates at a fixed distance from the apex, migrates to a random position during growth arrest, and moves from branch to branch in a mutant with branched hairs. Consistently, an artificial increase of the distance between the nucleus and the apex, achieved by entrapment of the nucleus in a laser beam, stops cell growth. Drug studies show that microt...

The two aspects of a scanning tunneling microscopy tip, the macroscopic profile and the nanoscale apex, can be tailored by controlling the tension during electrochemical etching and the solution-electrode contact area via acetone vapor. The apex diameter is shown to be proportional to the square root of the tension, and is demonstrated over apex diameters of 150-500 nm. The apex was found to be...

The objective of this study was to compare, ex vivo, the accuracy of three electronic apex locators (EALs), Root ZX II, Root ZX Mini and RomiApex A-15, in detecting the apical foramen (AF). Forty extracted single-Rooted human teeth with vital pulp were used in this study. After access preparation, the Root canal length of each tooth was measured by placing a #10 file until the tip was visible a...

Background. In this study, the cut-out risk of Dynamic Hip Screw (DHS) was investigated in nine different positions of the lag screw for two fracture types by using Finite Element Analysis (FEA). Methods. Two types of fractures (31-A1.1 and A2.1 in AO classification) were generated in the femur model obtained from Computerized Tomography images. The DHS model was placed into the fractured femur...

The effect of tip chemical reactivity on the lateral manipulation of intrinsic Si adatoms toward a vacancy site on a Si(111)-(7 × 7) surface has been investigated by noncontact atomic force microscopy at room temperature. Here we measure the atom-hopping probabilities associated with different manipulation processes as a function of the tip-surface distance by means of constant height scans wit...

We have measured forces between an atomically defined W(111) tip and an Au(111) sample in ultrahigh vacuum at 150 K. The W tips are manipulated and characterized on an atomic scale both before and after sample approach by field ion microscopy. Forces between the tip and the sample are measured by an in situ differential interferometer. We observe strong attractive adhesion forces, which turn re...

introduction: the aim of this in vitro study was to evaluate the correlation between accuracy of root zx electronic foramen locator and root canal curvature. methods and materials: one hundred and ten extracted mandibular molars were selected. access cavity was prepared and coronal enlargement of mesiobuccal canal was performed. a #10 flexofile was inserted into the mesiobuccal canal, and a rad...

Creating and maintaining cell polarity are complex processes that are not fully understood. Fungal hyphal tip growth is a highly polarized and dynamic process involving both F-actin and microtubules (MTs), but the behaviour and roles of the latter are unclear. To address this issue, MT dynamics and subunit distribution were analysed in a strain of Aspergillus nidulans expressing GFP-alpha-tubul...

The efficacy of tactile detection of the apical constriction in flared and nonflared root canals was examined in 120 root canals of adult patients. In 68 nonflared (group 1) root canals, a #15 or #20 K-file was used to detect ("feel") the apical constriction. In 52 teeth (group 2), Hedstrom files, Gates Gliden drills #2 to #4, and ultrasonic files were used to enlarge the canal orifice and flar...

Tunneling between a photoexcited p-type silicon tip and a gold surface is studied as a function of tip bias, tip-sample distance, and light intensity. In order to extend the range of application of future spin injection experiments, the measurements are carried out under nitrogen gas at room temperature. It is found that, while tunneling of valence band electrons is described by a standard proc...