Many organs are composed of epithelial tubes that transport vital fluids. Such tubular organs develop in many different ways and generate tubes of widely varying sizes and structures, but always with the apical epithelial surface lining the lumen. We describe recent progress in several diverse cell culture and genetic models of tube morphogenesis, which suggest apical membrane biogenesis, vesic...

BACKGROUND AND AIMS In trees, bud development is driven by endogenous and exogenous factors such as species and climate, respectively. However, knowledge is scarce on how these factors drive changes in bud size across different time scales. METHODS The seasonal patterns of apical bud enlargement are related to primary and secondary growth in two coexisting Mediterranean oaks with contrasting ...

AIM To evaluate root canal transportation at the major foramen through the use of stainless steel size 08 K-Flex files, size 10 reamers, and XF finger spreaders when used as patency instruments. METHODOLOGY One hundred and two mesiobuccal canals of maxillary and mandibular first molars were randomly divided into three groups (34 canals each). Size 08 stainless steel K-Flex files, size 10 stai...

the quality of plant stocks in the nursery has proven to be a key determinant factor in precocity of fruit bearing period and the size of tree crops. the quality of these trees is related to growth strength of the applied rootstock, the tendency of the cultivars to produce branches, the growth season's weather conditions as well as the efficiency of different treatments stimulating branchi...

introduction: determination of the canal working length with radiographs has many drawbacks. electronic apex locators have been developed to overcome some of these problems. recently, a newly designed apex locator called novapex has been introduced. all the studies conducted to determine the accuracy of novapex have been carried out in-vitro on extracted teeth. the aim of this in vivo study was...

The switch of neural stem and progenitor cells from proliferation to differentiation during development is a crucial determinant of brain size. This switch is intimately linked to the architecture of the two principal classes of neural stem and progenitor cells, the apical (neuroepithelial, radial glial) and basal (intermediate) progenitors, which in turn is crucial for their symmetric versus a...

OBJECTIVES To evaluate the effect of spreader size on apical leakage of maxillary incisor teeth. MATERIALS AND METHODS A total of 75 permanent human teeth with no carious and no fracture or crack were used for this study. After removing the crown from the cementoenamel junction and the standardization of the root lengths, the specimens were randomly divided into five groups: Group 1 - Roots w...

objectives: this study aimed to assess and compare the apical sealing ability of herofill® soft-core system and lateral condensation technique in fine curved canals using the fluid filtration method. materials and methods: forty human mesiobuccal root canals of mandibular first molars with 25° to 40° curvatures were instrumented to an apical size 30/0.04. roots were randomly assigned to two exp...