Groups of nucleotide sequences in the genes coding for the chains of the T cell receptor and in the immunoglobulin heavy- and light-chain genes which are recombined during lymphocyte development and which contribute to the genes coding for variable domains.

2. J wave of Osborn
Author: Guo Li
Definition:

The J wave of Osborn is an electrographic abnormality that is indicative of hypothermia. It is an upward wave immediately following the S wave in a QRS complex.

3. Jaccard coefficient (SJ)
Author: Mirrored from Tsute Chen's Glossary of Microbiology
Definition:

An association coefficient used in numerical taxonomy; it is the proportion of characters that match, excluding those that both organisms lack.

4. jack
Author:
Definition:

Young salmon, usually a male, that matures precociously.

5. jack (jackstraw)
Author:
Definition:

Bank protection element consisting of wire or cable strung on three mutually perpendicular struts.

6. jacklines
Author:
Definition:

A series of large steel or iron "jacks," usually up to 10 feet in height and cabled together at intervals and "deadmanned" to the bank or tied to trees along the margin of a stream to prevent cutting and eroding by slowing down high velocity flows. Can help reclaim eroded soils by trapping silt, sand, etc.

7. jam
Author:
Definition:

Wedged collection of drift in a constriction of a channel, such as a gorge or bridge opening.

8. Japanese B encephalitis
Definition:

An epidemic viral encephalitis that strikes populations in Japan and other East Asian countries, typically in summer months. Symptoms can resemble poliomyelitis, but the disease can also be virtually symptomless.

9. jaundice (icterus)
Definition:

Yellowing of the skin and eyes due to excessive bilirubins (bile pigments) in the blood; it is often a major symptom of hepatitis. Jaundice becomes recognizable when the total amount of blood bilirubins is greater than 50 umols per liter.

10. jaw thrust maneuver
Author: Guo Li
Definition:

The jaw thrust maneuver is a method of maintaining an open airway of an unconscious individual. Jaw thrust is used to open the mouth and lift the tongue which obstructs the patency of the airway. It is usually performed by placing on each side of the face, the index and middle fingers at the angle of the mandible. The thumbs are placed on the chin just below the lower lip. As the mouth is opened by exerting downward force on the chin, the index and middle fingers would lift the entire mandible anterior thus moving the base of the tongue out of obstruction.

11. jejunostomy
Author: Guo Li
Definition:

Jejunostomy is surgery in which the jejunum is brought outside of the abdominal wall and opened.

12. jejunum
Definition:

The jejunum is the portion of the small intestine which joins the pylorus of the stomach to the cecum. It is the middle part of the small intestine, between the duodenum and the ileum.

13. jelly fungus (trembling fungus, tremmellales)
Definition:

Any of several fungi in the order Tremellales, which are characterized by gelatinous fruiting bodies.

14. jet
Author:
Definition:

An effluent stream from a restricted channel, including a fast current through a slower stream.

15. jetty
Author:
Definition:

An elongate artificial obstruction projecting into a stream or the sea from bank or shore to control shoaling and scour by deflection of strength of currents and waves.

16. jimson weed (jimsonweed, jimpson, datura)
Definition:

A poisonous annual plant (Datura stramonium) in Solanaceae, the nightshade family. It has stinky leaves and white trumpet-shaped blooms and is the source of many useful alkaloids, including atropine, hyoscine and hyoscamine. It's name is a corruption of "Jamestown weed"; reputedly, the early settlers in Jamestown, Virginia discovered the toxic effects of the plant when a cook collected several of them as a side dish to a meal.

17. Johansen, Wilhelm
Definition:

A Dutch geneticist who lived from 1857 to 1927; he coined the word "gene" and demonstrated that environmental adaptations are not inherited.

18. joining segment
Author: Susan A.Hagedorn
Definition:

A small DNA segment that links genes to yield a functional gene encoding an immunoglobulin.

19. joints
Definition:

A joint is the place where two or more bones connect. Joints are made of connective tissue and cartillage and can be classified as:

• fibrous joints (such as those in the skull) connect bones with fibrous connective tissue; they allow little or no movement.
• cartilaginous joints (vertebrae, for example) connect bones with cartilage and fibrous connective tissue; they also allow little or no movement.
• synovial joints contain synovial fluid, which lubricate the joint and absorbs frictional heat created by the joint's movement. There are several sub-types of synovial joints:
  • ball and socket joint: the rounded head of one bone fits into a socket-like cavity of another, such as the hip and shoulder joints. These joints allow free rotation
  • hinge joint: elbow and ankles. These joints allow for flexion and extension.