Search results
Results from the WOW.Com Content Network
The lanthanide contraction is the greater-than-expected decrease in atomic radii and ionic radii of the elements in the lanthanide series, from left to right. It is caused by the poor shielding effect of nuclear charge by the 4f electrons along with the expected periodic trend of increasing electronegativity and nuclear charge on moving from left to right.
The lanthanide contraction, i.e. the reduction in size of the Ln 3+ ion from La 3+ (103 pm) to Lu 3+ (86.1 pm), is often explained by the poor shielding of the 5s and 5p electrons by the 4f electrons. [18] Lanthanide oxides: clockwise from top center: praseodymium, cerium, lanthanum, neodymium, samarium and gadolinium.
Fiber length is also a key variable in muscle anatomy. Fiber length is the product of both the number of sarcomeres in series in the fiber and their individual lengths. As a fiber changes length, the individual sarcomeres shorten or lengthen, but the total number does not change (except on long timescales following exercise and conditioning).
For example, the pronator teres muscle of the forearm. Unipennate muscles have fibres that run the entire length of only one side of a muscle, like a quill pen. For example, the fibularis muscles. Bipennate muscles consist of two rows of oblique muscle fibres, facing in opposite diagonal directions, converging on a central tendon.
The effect of the lanthanide contraction can be observed in the REE behaviour both in a CHARAC-type geochemical system (CHArge-and-RAdius-Controlled [40]) where elements with similar charge and radius should show coherent geochemical behaviour, and in non-CHARAC systems, such as aqueous solutions, where the electron structure is also an ...
With the large 4f orbitals, lanthanide elements display properties significantly different from the common d-block transition metals. The large ionic radii limits the extent to which 4f orbitals can overlap with ligands, but at the same time allows the organolanthanide complexes to attain higher coordination numbers. [ 5 ]
Diagram of skeletal muscle fiber structure. Skeletal muscle cells are the individual contractile cells within a muscle and are more usually known as muscle fibers because of their longer threadlike appearance. [10] Broadly there are two types of muscle fiber performing in muscle contraction, either as slow twitch or fast twitch .
A classic example of a syncytium is the formation of skeletal muscle.Large skeletal muscle fibers form by the fusion of thousands of individual muscle cells. The multinucleated arrangement is important in pathologic states such as myopathy, where focal necrosis (death) of a portion of a skeletal muscle fiber does not result in necrosis of the adjacent sections of that same skeletal muscle ...