CEO Foreword: The Centennial Presidential Advisory

Most animal cells comprise a pair of centrioles together called a centrosome. The cell duplicates its centrosome and contains two centrosomes side-by-side, which begin to move apart during the prophase. As the centrosomes migrate to two different sides of the cell, microtubules start extending from each centrosome toward the other end. The mitotic spindle is composed of the centrosomes and their emerging microtubules.
Near the end of the prophase, also called late prophase or...

Pseudo forces, or fictitious forces, appear to act on an object in motion in a rotating frame of reference with respect to an inertial reference frame. These forces are not real forces but rather mathematical constructs and are introduced to simplify calculations in a non-inertial frame while using Newton's laws of motion. Common examples of pseudo forces include centrifugal, Coriolis, and Euler forces. These forces are essential in fields such as mechanics, astrophysics, and fluid...

The center of mass of an object is defined as the mass-weighted average position of all the particles that comprise the object. The significance of the center of mass of an object can be seen by looking at its dynamics. The time derivative of the center of mass gives its velocity, assuming that the object's mass remains constant over time. Furthermore, the total linear momentum of an object can be seen as the linear momentum of a single particle of the object's total mass moving with...

The primary microtubule organizing center (MTOC) in animal cells is the centrosome. A centrosome has two cylindrical centrioles at its core. Each centriole consists of nine sets of three microtubules held together by proteins. The centrioles are positioned at right angles to each other and surrounded by a shapeless protein cloud called the pericentriolar matrix, or pericentriolar material (PCM).
To ensure that each daughter cell receives a centrosome after cell division, centrosome duplication...

The paraboloid of revolution is an axially symmetric surface generated by rotating a parabola around its axis. This shape has several applications in mechanical engineering due to its advantageous structural properties, such as strength against stress concentration points and rotational symmetry.
The centroid for the paraboloid of revolution is the point where all the mass of the paraboloid is concentrated. This centroid is important for engineering applications, as it determines how forces are...

The centroid is an important concept in engineering, physics, and mechanics. It is the geometric center of a body. It always lies within the body except in cases with holes or cavities. When the material that a body is composed of is uniform or homogeneous, the centroid coincides with its center of mass or the center of gravity.
For a homogeneous body with constant density, the centroid can usually be found using equations representing a balance of the moments of the body's volume. If the...