Monomethylhydrazine: Hydrazine substituted by one methyl group.Maximum Allowable Concentration: The maximum exposure to a biologically active physical or chemical agent that is allowed during an 8-hour period (a workday) in a population of workers, or during a 24-hour period in the general population, which does not appear to cause appreciable harm, whether immediate or delayed for any period, in the target population. (From Lewis Dictionary of Toxicology, 1st ed)Spacecraft: Devices, manned and unmanned, which are designed to be placed into an orbit about the Earth or into a trajectory to another celestial body. (NASA Thesaurus, 1988)Diving: An activity in which the organism plunges into water. It includes scuba and bell diving. Diving as natural behavior of animals goes here, as well as diving in decompression experiments with humans or animals.Atmosphere: The gaseous envelope surrounding a planet or similar body. (From Random House Unabridged Dictionary, 2d ed)Chemical Terrorism: The use of chemical agents in TERRORISM. This includes the malevolent use of nerve agents, blood agents, blister agents, and choking agents (NOXAE).Saturn: The sixth planet in order from the sun. It is one of the five outer planets of the solar system. Its twelve natural satellites include Phoebe and Titan.Space Flight: Travel beyond the earth's atmosphere.New HampshirePlants, Edible: An organism of the vegetable kingdom suitable by nature for use as a food, especially by human beings. Not all parts of any given plant are edible but all parts of edible plants have been known to figure as raw or cooked food: leaves, roots, tubers, stems, seeds, buds, fruits, and flowers. The most commonly edible parts of plants are FRUIT, usually sweet, fleshy, and succulent. Most edible plants are commonly cultivated for their nutritional value and are referred to as VEGETABLES.Vegetables: A food group comprised of EDIBLE PLANTS or their parts.Fruit: The fleshy or dry ripened ovary of a plant, enclosing the seed or seeds.Diet: Regular course of eating and drinking adopted by a person or animal.Ethnobotany: The study of plant lore and agricultural customs of a people. In the fields of ETHNOMEDICINE and ETHNOPHARMACOLOGY, the emphasis is on traditional medicine and the existence and medicinal uses of PLANTS and PLANT EXTRACTS and their constituents, both historically and in modern times.MaineAerosol Propellants: Compressed gases or vapors in a container which, upon release of pressure and expansion through a valve, carry another substance from the container. They are used for cosmetics, household cleaners, and so on. Examples are BUTANES; CARBON DIOXIDE; FLUOROCARBONS; NITROGEN; and PROPANE. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Tongue Habits: Acquired responses regularly manifested by tongue movement or positioning.Gas PoisoningMars: The fourth planet in order from the sun. Its two natural satellites are Deimos and Phobos. It is one of the four inner or terrestrial planets of the solar system.Ultrasonography, Doppler, Transcranial: A non-invasive technique using ultrasound for the measurement of cerebrovascular hemodynamics, particularly cerebral blood flow velocity and cerebral collateral flow. With a high-intensity, low-frequency pulse probe, the intracranial arteries may be studied transtemporally, transorbitally, or from below the foramen magnum.Extraterrestrial Environment: The environment outside the earth or its atmosphere. The environment may refer to a closed cabin (such as a space shuttle or space station) or to space itself, the moon, or other planets.Blood Flow Velocity: A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.Logic: The science that investigates the principles governing correct or reliable inference and deals with the canons and criteria of validity in thought and demonstration. This system of reasoning is applicable to any branch of knowledge or study. (Random House Unabridged Dictionary, 2d ed & Sippl, Computer Dictionary, 4th ed)Tricuspid Valve Stenosis: The pathologic narrowing of the orifice of the TRICUSPID VALVE. This hinders the emptying of RIGHT ATRIUM leading to elevated right atrial pressure and systemic venous congestion. Tricuspid valve stenosis is almost always due to RHEUMATIC FEVER.Telemetry: Transmission of the readings of instruments to a remote location by means of wires, radio waves, or other means. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Equipment Design: Methods of creating machines and devices.Automobile Driving: The effect of environmental or physiological factors on the driver and driving ability. Included are driving fatigue, and the effect of drugs, disease, and physical disabilities on driving.Aortic Valve: The valve between the left ventricle and the ascending aorta which prevents backflow into the left ventricle.Vehicle Emissions: Gases, fumes, vapors, and odors escaping from the cylinders of a gasoline or diesel internal-combustion engine. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed & Random House Unabridged Dictionary, 2d ed)Illusions: The misinterpretation of a real external, sensory experience.Patents as Topic: Exclusive legal rights or privileges applied to inventions, plants, etc.Chlorofluorocarbons: A series of hydrocarbons containing both chlorine and fluorine. These have been used as refrigerants, blowing agents, cleaning fluids, solvents, and as fire extinguishing agents. They have been shown to cause stratospheric ozone depletion and have been banned for many uses.Plasma Gases: Ionized gases, consisting of free electrons and ionized atoms or molecules which collectively behave differently than gas, solid, or liquid. Plasma gases are used in biomedical fields in surface modification; biological decontamination; dentistry (e.g., PLASMA ARC DENTAL CURING LIGHTS); and in other treatments (e.g., ARGON PLASMA COAGULATION).Hydrocarbons, FluorinatedJupiter: The fifth planet in order from the sun. It is one of the five outer planets of the solar system. Its sixteen natural satellites include Callisto, Europa, Ganymede, and Io.Tissue Engineering: Generating tissue in vitro for clinical applications, such as replacing wounded tissues or impaired organs. The use of TISSUE SCAFFOLDING enables the generation of complex multi-layered tissues and tissue structures.Ecological Systems, Closed: Systems that provide for the maintenance of life in an isolated living chamber through reutilization of the material available, in particular, by means of a cycle wherein exhaled carbon dioxide, urine, and other waste matter are converted chemically or by photosynthesis into oxygen, water, and food. (NASA Thesaurus, 1988)Dictionaries, MedicalHeadache: The symptom of PAIN in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of HEADACHE DISORDERS.Dictionaries as Topic: Lists of words, usually in alphabetical order, giving information about form, pronunciation, etymology, grammar, and meaning.Headache Disorders: Various conditions with the symptom of HEADACHE. Headache disorders are classified into major groups, such as PRIMARY HEADACHE DISORDERS (based on characteristics of their headache symptoms) and SECONDARY HEADACHE DISORDERS (based on their etiologies). (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Tension-Type Headache: A common primary headache disorder, characterized by a dull, non-pulsatile, diffuse, band-like (or vice-like) PAIN of mild to moderate intensity in the HEAD; SCALP; or NECK. The subtypes are classified by frequency and severity of symptoms. There is no clear cause even though it has been associated with MUSCLE CONTRACTION and stress. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Cluster Headache: A primary headache disorder that is characterized by severe, strictly unilateral PAIN which is orbital, supraorbital, temporal or in any combination of these sites, lasting 15-180 min. occurring 1 to 8 times a day. The attacks are associated with one or more of the following, all of which are ipsilateral: conjunctival injection, lacrimation, nasal congestion, rhinorrhea, facial SWEATING, eyelid EDEMA, and miosis. (International Classification of Headache Disorders, 2nd ed. Cephalalgia 2004: suppl 1)Liver Diseases: Pathological processes of the LIVER.Neurofeedback: A technique to self-regulate brain activities provided as a feedback in order to better control or enhance one's own performance, control or function. This is done by trying to bring brain activities into a range associated with a desired brain function or status.Sleep Initiation and Maintenance Disorders: Disorders characterized by impairment of the ability to initiate or maintain sleep. This may occur as a primary disorder or in association with another medical or psychiatric condition.Biofeedback, Psychology: The therapy technique of providing the status of one's own AUTONOMIC NERVOUS SYSTEM function (e.g., skin temperature, heartbeats, brain waves) as visual or auditory feedback in order to self-control related conditions (e.g., hypertension, migraine headaches).Imagery (Psychotherapy): The use of mental images produced by the imagination as a form of psychotherapy. It can be classified by the modality of its content: visual, verbal, auditory, olfactory, tactile, gustatory, or kinesthetic. Common themes derive from nature imagery (e.g., forests and mountains), water imagery (e.g., brooks and oceans), travel imagery, etc. Imagery is used in the treatment of mental disorders and in helping patients cope with other diseases. Imagery often forms a part of HYPNOSIS, of AUTOGENIC TRAINING, of RELAXATION TECHNIQUES, and of BEHAVIOR THERAPY. (From Encyclopedia of Human Behavior, vol. 4, pp29-30, 1994)Pilot Projects: Small-scale tests of methods and procedures to be used on a larger scale if the pilot study demonstrates that these methods and procedures can work.Alpha Rhythm: Brain waves characterized by a relatively high voltage or amplitude and a frequency of 8-13 Hz. They constitute the majority of waves recorded by EEG registering the activity of the parietal and occipital lobes when the individual is awake, but relaxed with the eyes closed.Spectroscopy, Near-Infrared: A noninvasive technique that uses the differential absorption properties of hemoglobin and myoglobin to evaluate tissue oxygenation and indirectly can measure regional hemodynamics and blood flow. Near-infrared light (NIR) can propagate through tissues and at particular wavelengths is differentially absorbed by oxygenated vs. deoxygenated forms of hemoglobin and myoglobin. Illumination of intact tissue with NIR allows qualitative assessment of changes in the tissue concentration of these molecules. The analysis is also used to determine body composition.