Sexual reproduction of flowering plants depends on delivery of the sperm to the egg, which occurs through a long, polarized projection of a pollen cell, called the pollen tube. The pollen tube grows exclusively at its tip, and this growth is distinguished by very fast rates and reaches extended lengths. Thus, one of the most fascinating aspects of pollen biology is the question of how enough ce...

Many objects in the real world are tubular in shape and this paper is about understanding this object class, which we refer to in the paper as generalized tubes (hereafter GTs). Intuitively, a GT is constructed by sweeping some planar closed curve (the GT cross-section) along a 3D space curve (the GT axis). First, we examine the GT class as a whole and identify two important GT subclasses where...

Background: Protein-calorie malnutrition is a common problem that develops in patients requiring management in the surgical intensive care unit (SICU). The use of durable enteral feeding tubes to help meet their nutritional needs has grown dramatically over that past three decades. However, prepyloric enteral feeding has been associated with increased aspiration risks. Hypothesis: We hypothesiz...

Pollen tubes formed following compatible and incompatible intraspecific matings in Petunia have been examined with light and electron microscopes. Compatible and incompatible tubes develop in an identical fashion on the stigma but, on entry into the top 1 mm of the stylar transmitting tissue changes occur both to the cytology of the tubes and their rates of growth. The early cytological changes...

The effects of several hormones on pollen tube growth were compared in Torenia fournieri and it was found that IAA was the most effective, stimulating pollen tube growth and causing the shank part of pollen tubes to be slender and straighter. The role of IAA was investigated by studying the changes in ultrastructure and PM H(+)-ATPase distribution in the pollen tubes and the modification of the...

Cylindrical thin-walled tubes due to construction and easy installation, high energy absorption capacity are used in the automotive industry as an impact energy absorber. However, the main weakness of cylindrical tubes is in the high initial peak load. Therefore, in this paper, to overcome this weakness, a buckling initiator is used at the top of the tube. This buckling initiator is a steel rod...

In this study, the concrete-steel bond strength of concrete filled cylindrical steel tubes has been experimentally investigated. 22 short, high strength and normal concrete filled circular steel tubes were tested. Push-out test was carried out as the common method to evaluate the bond carrying capacity. Four different concrete mixes were used in preparing the specimens. The steel tubes were w...

cylindrical thin-walled tubes due to construction and easy installation, high energy absorption capacity are used in the automotive industry as an impact energy absorber. however, the main weakness of cylindrical tubes is in the high initial peak load. therefore, in this paper, to overcome this weakness, a buckling initiator is used at the top of the tube. this buckling initiator is a steel rod...

We tested for soil substrate effects on the movement and infectivity of naturally co-occurring entomopathogenic nematodes Steinernema feltiae and Heterorhabditis marelatus, alone and in combination. We manipulated the presence and bulk density of soil and added Galleria mellonella baits within capped and perforated 15mL centrifuge tubes. Sampling tubes were then deployed in situ into field and ...

BACKGROUND Molar bonding procedures need continuous improvement to be widely accepted clinically and eventually replace molar bands. MATERIAL AND METHODS The purpose of this study was to determine the effects of enamel micro-abrasion and silane coating of the base of molar tubes on shear and tensile bond strengths of orthodontic molar tubes. A total of 200 third molars were randomly allocated...