Lexikon

1 - 19 / 19 megjelenítése
1 | 2 | 6 | 9 | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Z
aliphatic hydrocarbons
hydrocarbons in which the carbon-hydrogen groupings are arranged in open chains (that might include branches). The term includes paraffins and olefins and provides a distinction from aromatics and naphthenes, which have at least some of their carbon atoms arranged in closed chains or rings. The paraffins, called also alkanes are saturated hydrocarbons, in their molecules the carbon atoms are bound by single bonds, e.g. hexadecane (C16H34). The olefins are unsaturated hydrocarbons, in their molecules there are carbon atoms, which are bound by double bond, e.g. hexadecene (C16H34) contains one double bond, butadiene (C4H4) contains two double bonds.
androgen hormones

any steroid hormone that promotes male secondary sex characters. The two main androgens are androsterone and testosterone. Called also androgenic hormone.  

The androgenic hormones are internal endocrine secretions circulating in the bloodstream and manufactured mainly by the testes under stimulation from the pituitary gland. To a lesser extent, androgens are produced by the adrenal glands in both sexes, as well as by the ovaries in women. Thus women normally have a small percentage of male hormones, in the same way that men's bodies contain some female sex hormones, the estrogens. Male secondary sex characters include growth of the beard and deepening of the voice at puberty. Androgens also stimulate the growth of muscle and bones throughout the body and thus account in part for the greater strength and size of men as compared to women.

Source: medical-dictionary.thefreedictionary.com/Anti-androgen

antiandrogen

antoandrogen is a substance that blocks the action of androgens, the hormones responsible for male characteristics. Used to treat prostate cancers that require male hormones for growth.

Many of the natural and man-made environmental contaminants have antiandrogenic effect, phtalates are one example for that.

Environmental compounds affecting the endocrine system, are called are antagonistic to any biochemical molecule of the hormon system. Antiandrogenic chemical substances antagonistically affect androgen receptors and androgen production can negatively affect individuals that come in contact with the compounds. As antoandrogens affect male sex-hormone system, thay are considered as reprotoxic chemical substances, impacting future generations too.

Certain pesticides and insecticides as well as in industrial chemicals contain antiandrogenic chemicals. Natural compounds, such as biologically active phytochemicals may also have antiandrogenic effects. Exposure to these environmental antiandrogens has resulted in adverse effects on animals and from animal testresults and biomonitoring data we can predict the human health riskss of these chemical compound.

Exposure to pesticides and insecticides with antiandrogenic properties has been found to negatively affect humans and laboratory animals. Androgens are important in fetal development as well as in pubertal development. Exposure during critical periods of development can cause reproductive malformations in males while exposure after birth and before puberty can delay pubertal development (Wikipedia).

Animal studies with vinclozolin, procymidone, linuron, and the DDT metabolite dichlorodiphenyldichloroethylene (p.p’-DDE) show irregular reproductive development due to their function as androgen receptor antagonists that inhibit androgen-activated gene expression. Even with low doses of antiandrogenic pesticides, developmental effects such as reduced anogenital distance and induction of areolas were seen in male rats (Gray et al. 2001).

Animal studies show that deformities result in offspring exposed to antiandrogens. Male mice can display malformations that resemble the reproductive organs of females as in the case of exposure to vinclozolin or proymidone. Exposure to vinclozolin or procymidone in utero feminized male offspring, as seen in abnormalities of anogenital distance, small or absent sex accessory glands, hypospadias, undescended testes, retained nipples, cleft phallus, and presence of a vaginal pouch. Male mice exposed before puberty to vinclozolin experienced delayed pubertal development visualized by delayed onset of androgen-dependent preputial separation (Grey et al. 2001).

Ketoconazole's imidazole derivative is used as a broad-spectrum antifungal agent effective against a variety of fungal infections. Although ketoconazole is a relatively weak antiandrogen, side-effects seen as a result of exposure include serious liver damage and reduced levels of androgens from both the testicles and adrenal glands (Grey et al. 2001)

Many organophostphate insecticides behave as androgen receptor antagonists.

Industrial chemicals with antiandrogenic effects are ubiquitous in the environment. Consumer products such as toys and cosmetics may contain phthalates. Phthalates are mainly found in plastics. Fetuses that are exposed to a mixture of pthalates in utero may show signs of disrupted reproductive development. When Di-n-butyl phthalate (DBP), diisobutyl phthalate (DiBP), benzyl butyl phthalate (BBP), Bis(2-ethylhexyl) phthalate (DEHP) and di-n-pentyl phthalate (DPP) were combined, reductions in both testosterone synthesis and gene expression of steroidogenic pathway proteins were seen. The result in male rats was undescended testes and abnormal development of reproductive tissues ( Rieder et al. 2010)

Parabens are commonly found in cosmetics and pharmaceuticals. Paraben esters have been found to mimic androgen antagonist activity. Antiandrogenic endocrine disruption has been shown in aquatic species but the mechanism is unknown.

Natural antiandrogenic chemicals of plant origin are mentioned here (Wikipedia):

3,3'-Diindolylmethane (DIM) is definitely antiandrogen, deriving from the digestion of indole-3-carbinol, found in cruciferous vegetables such as broccoli, Brussels sprouts, cabbage and kale. Spearmint tea has antiandrogenic properties in females with hirsutism (excessive hairiness on women). The plant Scutellaria baicalensis (North American skullcap) may also have antiandrogenic properties. The compound N-butylbenzene-sulfonamide (NBBS) isolated from Pygeum africanum (an evergreen tree from Sub-Saharan Africa) is a specific androgen antagonist. Glycyrrhiza glabra (liquorice, a plant to extract sweetener from) has shown antiandrogenic activity in male rats. A herbal formula (termed KMKKT) containing Korean Angelica gigas (a perennial plant grown in China and Korea) Nakai (AGN) root and nine other oriental herbs has shown in vitro anti-androgen activity.

Sources:

Gray LE, Ostby J, Furr J, Wolf CJ, Lambright C, Parks L, Veeramachaneni DN, Wilson V, Price M, Hotchkiss A, Orlando E, Guillette L. (2001). "Effects of environmental antiandrogens on reproductive development in experimental animals". Human Reproduction Update 2: 248–64, http://www.ncbi.nlm.nih.gov/pubmed/11392371

Rider CV, Furr JR, Wilson VS, Gray LE Jr. (Apr 2010). "Cumulative effects of in utero administration of mixtures of reproductive toxicants that disrupt common targe tissues via diverse mechanisms of toxicity". International Journal of Andrology 33: 443–62, http://www.ncbi.nlm.nih.gov/pubmed/2048704

Wikipedia: http://en.wikipedia.org/wiki/Antiandrogen

contaminant hydrology
the study of the environmental fate and transport of antropogenic chemicals in groundwater (Source: EUGRIS)
DRO
DRO range, Diesel Range Organics called also as extractable Total petroleum hydrocarbon (EPTH) consists of hydrocarbons containing of 10 to 30 carbon atoms with boiling point of 160-560 oC and includes a mixture of polyaromatic compounds, alkanes, cycloalkanes, branched alkanes, alkenes and heterocyclic compounds. The Extended DRO range includes compounds with up to 40 carbon atoms and includes compounds found in lubricating oils. DRO is distinguished from GRO (Gasoline Range Organics) containing the volatile (lower than C12) organic compounds.
drought

drought means the naturally occurring phenomenon that exists when precipitation has been significantly below normal recorded levels, causing serious hydrological imbalances that adversely affect land resource production systems;

effective hydrodynamic radius
effective radius of a hydrated molecule in solution or the radius of a hard sphere that diffuses at the same rate as the molecule, expressed in m.
hydrocarbons

molecules that consist only of hydrogen and carbon atoms. hydrocarbons can be found in raw oil (petroleum hydrocarbons), gas and coal. hydrocarbons can be aliphatic hydrocatrbons with methane as the simplest and aromatics with benzene as the basic unit. The aliphatic hydrocarbons can be divided into alkanes, alkenes and alkines depending on the carbon-carbon bond.

hydroelectricity

water generates electricity when it drops gravitationally, driving a turbine and generator. While most hydroelectricity is produced by water falling from dams, some is produced by water flowing down rivers (run-of-the-river electricity).

Conventionally, hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. The power extracted from the water depends on the volume and on the difference in height between the source and the water's outflow. This height difference is called the head. The amount of potential energy in water is proportional to the head. A large pipe (the "penstock") delivers water to the turbine.

Pumped-storage hydroelectric power plant produces electricity to supply high peak demands by moving water between reservoirs at different elevations. At times of low electrical demand, excess generation capacity is used to pump water into the higher reservoir. When there is higher demand, water is released back into the lower reservoir through a turbine. Pumped-storage schemes currently provide the most commercially important means of large-scale grid energy storage and improve the daily capacity factor of the generation system.

Run-of-the-river hydroelectric stations are those with small or no reservoir capacity, so that the water coming from upstream must be used for generation at that moment, or must be allowed to bypass the dam.

A tidal power plant makes use of the daily rise and fall of ocean water due to tides; such sources are highly predictable, and if conditions permit construction of reservoirs, can also be dispatchable to generate power during high demand periods. Less common types of hydro schemes use water's kinetic energy or undammed sources such as undershot waterwheels.

An underground power station makes use of a large natural height difference between two waterways, such as a waterfall or mountain lake. An underground tunnel is constructed to take water from the high reservoir to the generating hall built in an underground cavern near the lowest point of the water tunnel and a horizontal tailrace taking water away to the lower outlet waterway.

Source: http://en.wikipedia.org/wiki/Hydroelectricity

hydrogen fuel cell vehicle (HFCV)

hydrogen fuel cell vehicles (HFCVs) use a fuel cell to convert hydrogen fuel and oxygen from air into electricity which is used to run an electric motor. HFCVs are truly clean only if the hydrogen is produced by passing WWS-derived electricity through water (electrolysis). Several companies have prototype HFCVs, and California has about 200 HFCVs on the road (California Fuel Cell Partnership, 2009). Hydrogen fueling stations, though, are practically non-existent and most hydrogen today is produced by steam-reforming of natural gas, which is not as clean as that produced by WWS-electrolysis.

hydrogeology, EUGRIS

is the area of geology that deals with the distribution and movement of groundwater in the soil and rocks of the Earth's crust, (commonly in aquifers). The term geohydrology is often used interchangeably. Some make the minor distinction between a hydrologist or engineer applying themselves to geology (geohydrology), and a geologist applying themselves to hydrology (hydrogeology). (Source: Wikipedia)

EUGRIS defines hydrogeology as the study of the geological factors relating to the subsurface waters.

hydrolysis
hydrometry
hydroxypropyl beta-cyclodextrin
abbreviated as HPBCD, a sugar derivative of good solubilizing capacity. By molecular encapsulation (inclusion complex formation) it can dissolve water-insoluble organic compounds, e.g. hydrocarbons in water. It is of ring shape molecule, a cyclodextrin unit with 3-6 hydroxypropyl substituents. It is utilized for mobilizing the organic pollutants in soil (→"sugar flushing" technology), for improving the bioavailability and biodegradability of these contaminants. HPBCD is fast biodegraded in soils (half life time is < 1 year). It is not harmful for the soil microflora, improves the availability of their nutrients. It is harmless for the humans as well, is used as pharmaceutical excipient and as an additive in various food products.
petroleum hydrocarbon
polycyclic aromatic hydrocarbons
abbreviated as PAH (see PAH)
syndrome

the group or recognizable pattern of symptoms or abnormalities that indicate a particular trait or disease.

Total Petroleum Hydrocarbon (TPH)
water scarcity and drought

water scarcity and drought are different phenomena although they are liable to aggravate the impacts of each other. In some regions, the severity and frequency of droughts can lead to water scarcity situations, while overexploitation of available water resources can exacerbate the consequences of droughts. Therefore, attention needs to be paid to the synergies between these two phenomena, especially in river basins affected by water scarcity.

Water scarcity occurs where there are insufficient water resources to satisfy long-term average requirements. It refers to long-term water imbalances, combining low water availability with a level of water demand exceeding the supply capacity of the natural system.

Water availability problems frequently appear in areas with low rainfall but also in areas with high population density, intensive irrigation and/or industrial activity. Large spatial and temporal differences in the amount of water available are observed across Europe.

Beyond water quantity, a situation of water scarcity can also emerge from acute water quality issues (e.g. diffuse or point source pollutions) which lead to reduced fresh/clean water availability.

Currently the main way of assessing Water Scarcity is by means of the Water Exploitation Index (WEI) applied on different scales (i.e. national, river basin). The WEI is the average demand for freshwater divided by the long-term average freshwater resources. It illustrates to which extent the total water demand puts pressure on the available water resource in a given territory and points out the territories that have high water demand compared to their resources.

The maps attached as links show the WEI for the European river basins in 2000 and for a forecasted scenario in 2030.