Immunology

Study suggests remarkable approach to MS treatment

(Medical Xpress)—Multiple sclerosis (MS) is an autoimmune inflammatory disorder in which the immune system attacks the myelin sheath enveloping and insulating the nerves. A progressive disease that often results in severe ...

Genetics

A single DNA tweak leads to blond hair

A single-letter change in the genetic code is enough to generate blond hair in humans, in dramatic contrast to our dark-haired ancestors. A new analysis by Howard Hughes Medical Institute (HHMI) scientists has pinpointed ...

Oncology & Cancer

Cancer therapy that boosts immune system ready for wider testing

Two clinical trials led by Johns Hopkins Kimmel Cancer Center researchers in collaboration with other medical centers, testing experimental drugs aimed at restoring the immune system's ability to spot and attack cancer, have ...

Medical research

Study identifies how zebrafish regrow their brains

(Medical Xpress)—An international team of scientists has discovered the mechanism by which zebrafish can re-grow brain neurons after they have suffered traumatic brain injury, and that this mechanism is associated with ...

Medical research

Gene therapy reverses type 1 diabetes in mice

An experimental cure for Type 1 diabetes has a nearly 80 percent success rate in curing diabetic mice. The results, to be presented Saturday at The Endocrine Society's 93rd Annual Meeting in Boston, offer possible hope of ...

Medical research

Scientists identify pathway to curb spread of brain cancer

UT Southwestern researchers have identified a molecular pathway responsible for the spread of glioblastoma to surrounding tissue in the brain, as well as an existing drug that curbed tumor growth in animal models. The findings, ...

Oncology & Cancer

A silver bullet to beat cancer?

The internet is awash with stories of how silver can be used to treat cancer. Now, lab tests have shown that it is as effective as the leading chemotherapy drug - and may have fewer side-effects.

Psychology & Psychiatry

Do deficits in brain cannabinoids contribute to eating disorders?

A new report in Biological Psychiatry suggests that deficits in endocannabinoid function may contribute to anorexia nervosa and bulimia. Endocannabinoids are substances made by the brain that affect brain function and chemistry ...

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Ligand

In coordination chemistry, a ligand is an ion or molecule (see also: functional group) that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from covalent to ionic. Furthermore, the metal-ligand bond order can range from one to three. Ligands are viewed as Lewis bases, although rare cases are known involving Lewis acidic "ligands."

Metal and metalloids are bound to ligands in virtually all circumstances, although gaseous "naked" metal ions can be generated in high vacuum. Ligands in a complex dictate the reactivity of the central atom, including ligand substitution rates, the reactivity of the ligands themselves, and redox. Ligand selection is a critical consideration in many practical areas, including bioinorganic and medicinal chemistry, homogeneous catalysis, and environmental chemistry.

Ligands are classified in many ways: their charge, their size (bulk), the identity of the coordinating atom(s), and the number of electrons donated to the metal (denticity or hapticity). The size of a ligand is indicated by its cone angle.

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