BACKGROUND Valve sparing aortic root reimplantation technique in patients with aortic root aneurysm have shown excellent mid-term results. In conjunction with the diameter of the aortic root the mechanical leaflet stress increase, which might have an impact on long-term aortic valve function after valve sparing aortic root reimplantation. METHODS AND RESULTS From July 1993 to October 2001, 16...

statement of problem: currently there are three recognized theories about the diameter of prepared dowel space in endodontically treated teeth. diameter of the dowel is commonly contributed to the root fracture. purpose: this study used a 3 dimensional (3d) finite element method to predict stress distribution in endodontically treated central maxillary tooth with cast post and core with various...

There are many examples of branching networks in nature, such as tree crowns, river systems, arteries and lungs. These networks have often been described as being self-similar, or following scale-invariant branching rules, and this property has been used to derive several scaling laws. In this paper we model root systems of Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) as bra...

Growth of temperate lettuce (Lactuca sativa) plants aeroponically in tropical greenhouses under ambient root-zone temperatures (A-RZTs) exposes roots to temperatures of up to 40 degrees C during the middle of the day, and severely limits root and shoot growth. The role of ethylene in inhibiting growth was investigated with just-germinated (24-h-old) seedlings in vitro, and 10-d-old plants grown...

Characterization of decomposition dynamics of fine roots is essential for understanding vegetation–soil feedbacks and predicting ecosystem responses to future climate scenarios, given their more rapid turnover rates. Using a branch-order classification, we separated the fine root systems of Larix gmelinii into two classes: firstand second-order roots combined into one (lower-order); thirdand fo...

Although the optic tectum in non-mammals and its mammalian homolog, the superior colliculus, are involved in avoidance behaviors, whether and how tectal neurons respond to an object approaching on a collision course towards the animal remain unclear. Here we show by single unit recording that there exist three classes of looming-sensitive neurons in the pigeon tectal layer 13, which sends loomi...

Root reinforcement is a mechanism through which forests contribute to the prevention and mitigation of shallow instabilities in soils, one main hazards mountain areas. This study aims assess how spatial tree distribution whether thinning operations affect root most common forest types European Southern Alps. We measured size position trees 119 stands, belonging sweet chestnut, beech, Norway spr...