chromium

(redirected from Chromebook)
Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
Related to Chromebook: Chromebook Pixel

chromium

 (Cr) [kro´me-um]
a chemical element, atomic number 24, atomic weight 51.996. (See Appendix 6.) It is an essential dietary trace element, but hexavalent chromium is carcinogenic.
chromium 51 a radioactive isotope of chromium having a half-life of 27.7 days and decaying by electron capture, emitting gamma rays. It is used to label red blood cells for measurement of red cell mass or volume, survival time, and sequestration studies, and for the diagnosis of gastrointestinal bleeding, and is used to label platelets to study their survival. Symbol 51Cr.

chro·mi·um (Cr),

(krō'mē-ŭm),
A metallic element, atomic no. 24, atomic wt. 51.9961. A dietary essential bioelement. 51Cr (half-life of 27.70 days) is used as a diagnostic aid in many disorders (for example, gastrointestinal protein loss).
[G. chroma, color]

chromium

/chro·mi·um/ (Cr) (kro´me-um) a chemical element, at. no. 24. It is an essential dietary trace element, but hexavalent chromium is carcinogenic.
chromium 51  a radioactive isotope of chromium having a half-life of 27.7 days and decaying by electron capture with emission of gamma rays (0.32 MeV); it is used to label red blood cells for measurement of mass or volume, survival time, and sequestration studies, for the diagnosis of gastrointestinal bleeding, and to label platelets to study their survival.
chromium trioxide  chromic acid.

chromium (Cr)

[krō′mē·əm]
Etymology: Gk, chroma, color
a hard, brittle metallic element. Its atomic number is 24; its atomic mass is 51.99. It does not occur naturally in pure form but exists in combination with iron and oxygen in chromite, a mineral found chiefly in Africa, Albania, Russia, and Turkey. Chromium strongly resists corrosion and is used extensively to plate other metals, harden steel, and, in combination with other elements, form colored compounds. Stainless steels are more than 10% chromium and strongly resist rusting. Traces of chromium occur in plants and animals, and there is evidence that this element may be important in human nutrition, especially in carbohydrate metabolism. Some experts estimate that the safe and adequate daily intake of chromium ranges from 0.1 to 0.2 mg, depending on the age of the individual. Workers in chromite mines are susceptible to pneumoconiosis caused by the inhalation of chromite dust particles that lodge in the lung. Chromate salts have been identified as potential carcinogens. Chromium 51 isotope is used in blood studies.

chromium

A metallic element (atomic number 24; atomic number 51.99), which is an essential mineral that potentiates the action of insulin and is present in trace amounts in various enzymes; chromium is present in various foods including brewers’ yeast, whole grains, peanuts, wheat germ and skim milk.

chro·mi·um

(Cr) (krō'mē-ŭm)
A metallic element, atomic no. 24, atomic wt. 51.9961. A dietary essential bioelement, 51Cr (half-life of 27.70 days) is used as a diagnostic aid in many disorders (e.g., gastrointestinal protein loss).
[G. chrōma, color]

minerals

inorganic substances which are obtained in a well-balanced diet. The substances required in the largest amounts (sometimes known as macrominerals) are sodium, potassium, calcium, phosphorus and magnesium, and many others are essential in smaller amounts. Minerals are essential in all metabolic processes, from maintenance of cell volume and structure to muscle contraction and relaxation, regulation of acid-base equilibrium, protection from oxidative stress, bone metabolism, immune function and haemoglobin synthesis. No mineral supplements should be required for athletes who are consuming a well-balanced diet but they frequently take them, especially iron, magnesium and chromium. See Table 1.
Table 1: Micronutrients: minerals
Name and chemical symbolReference nutrient intake (adults, per day)SourcesFunctionsDeficiencyExcess
Calcium Ca700 mgMilk and milk products, green vegetables, soya beans, white bread, hard water
  • Crucial role in all cellular function, in neural transmission, muscle contraction, blood coagulation.
  • As phosphate in bones and teeth
  • Dietary deficiency not uncommon.
  • Rickets, osteomalacia from failure of Ca absorption in Vit D deficiency.
  • Low blood [Ca2+] causes tetany
Calcium deposits in soft tissue can occur, but probably not related to high intake
Chlorine Cl3.4 g (as chloride)Salt-containing foods
  • Major anion in ECF.
  • Role in maintaining electrical gradient across cell membranes
Unlikely with normal dietAs NaCl, risk factor for high blood pressure
Chromium Cr25 μgVegetables, cereals, meats, vegetable oils, whole grainsCo-factor for some enzymes involved in glucose and energy metabolism
  • Rare.
  • Impaired glucose metabolism
  • Inhibition of enzymes.
  • Occupational exposures can cause skin and kidney damage
Copper Cu900 μgMeat, drinking waterCo-factor for some enzymes; intermediate in electron transfer during oxidative phosphorylationLow activity of antioxidant enzymesVery high intake can cause liver damage
Iodine I140 μgSeafood, iodized salt, milk and milk products, meat and eggsSynthesis of thyroid hormonesThyroid swelling (goitre) with hypothyroidism: low BMR, lethargyRarely any effect; may exacerbate some skin diseases
Iron Fe
  • Women 14.8 mg
  • Men 8.7 mg
Liver, kidney, red meat, egg yolk, wholegrains, pulses, dark green vegetables, dried fruit, treacle, cocoa, molassesComponent of haemoglobin, myoglobin and many enzymes
  • Iron deficiency anaemia not uncommon.
  • In childhood, poor growth; impaired intellectual development
Can be toxic if very excessive. (from blood transfusions rather than from diet); gastrointestinal upset; may promote vascular disease
Fluoride F3-4 mgDrinking water, mostly as calcium fluoride; tea, seafoodMay be important in maintenance of bone structureIncreased risk of tooth decayUnlikely from dietary sources
Magnesium Mg
  • Women 270 mg
  • Men 300 mg
Cereals, milk, nuts, seeds, and green vegetablesCo-factor for enzymes essential in metabolism; role in calcium homeostasis; skeletal development; neuromuscular functionUncommon; can occur with malabsorption or in chronic renal failure, when it accompanies hypocalcaemiaUnlikely from dietary sources
Phosphorus-P550 mg (as phosphate)Milk, cheese, yogurt, meat, poultry, grains, fishAdenosine phosphate compounds vital in energy metabolism. With Ca in bones and teethOnly in severe malnutrition; muscle weakness, bone pain, rickets, anorexia, anaemiaIn treatment of osteoporosis or bone cancer with biphosphonates
Potassium K3.5 gFruit, vegetables, meat, wholegrains
  • Major intracellular cation; muscle contraction and nerve excitability.
  • Linked to acid-base regulation
  • Poor dietary intake rare. Can occur with prolonged use of diuretics and purgatives.
  • Muscular weakness; depression; confusion; cardiac arrhythmia
High ECF [K+] (hyperkalaemia) causes cardiac arrest
Selenium Se
  • Women 50 μg
  • Men 70 μg
Seafood, meat, grains, wheat flourKey component in the endogenous antioxidant, glutathione peroxidaseHealth implications of low intake in UK currently under DoH review. May cause abnormality of heart muscleExcessive supplements: hair loss, skin rash, neurological disorder
Sodium Na1.6 gMainly as salt: table salt, and in milk, meat, vegetables, sauces, pickles, processed foods, snacks, cheeseMajor extracellular cation; linked to ECF volume, hence to blood volume and blood pressure. Component of bone mineralLoss in sweat and diarrhoea; dilution in body fluids due to excess water intake. Weakness, cramp; faintness, confusionOedema, hypertension
Zinc Zn
  • Women 7.0 mg
  • Men 9.5 mg
Red meat, dairy products, eggs, wholegrains, peas, beans, nuts, lentils
  • Co-factor for many enzymes.
  • Synthesis of some proteins. Wound healing; immune system; physical and sexual development
  • Retarded skeletal growth; sexual immaturity.
  • Anorexia, fatigue
  • Nausea, vomiting, or anaemia with chronic excess.
  • Also decreases iron and copper bioavailability

chromium,

n an essential mineral that is associated with glucose tolerance, high cholesterol, blocked arteries, glaucoma, obesity, diabetes, and hypoglycemia. Not for use by chil-dren or pregnant or nursing women. Also called
chromium picolinate, chromium polynicotinate, or
chromium chloride.

chro·mi·um

(krō'mē-ŭm)
A metallic element and essential dietary bioelement; used as diagnostic aid in many disorders (e.g., gastrointestinal protein loss).
[G. chroma, color]

chromium

a chemical element, atomic number 24, atomic weight 51.996, symbol Cr. See Table 6.

chromium-51
a radioisotope of chromium having a half-life of 27.8 days; used to label red blood cells to determine red cell volume and red cell survival time. Symbol 51Cr. See also cr51edta.
chromium nutritional deficiency
possibly causally related to the onset of diabetes mellitus in primates.
chromium trioxide
possibly carcinogenic in humans. See also chromate.
References in periodicals archive ?
Specifically, data suggests a 2016 sales surge in both Chromebooks and ultraportable PCs as consumers continue to adopt Chromebooks into classroom settings and 2-in-1 ultraportable PCs maintain their trend status as the future of portable computing.
Chrome apps for Chromebooks, and books that can be enjoyed from any web browser.
Acer has been a leader in the Chromebook market, from
Finally, Chromebooks are best for consumers who are into Google's ecosystem and for those who spends much time browsing the internet.
At Summit, "acronymed" SIS, 60 Chromebooks are being launched as a Pilot Project (for we believe the first Private School in the UAE) especially focusing on the Grade 7 boys' classes.
The Chromebook also has the advantage of having a Linux operating system on top of the remote application, which runs Microsoft.
Laptops with Google's Chrome operating system, an alternative to Windows or Mac, are Chromebooks, and they are selling big.
The Chromebook comes with a 1366 x 768 pixel display, 16GB storage, 2GB of RAM, and a battery that is said to provide 6.
Google introduced the first Chromebook in mid-2010 in a challenge to Windows operating software at the heart of Microsoft's empire.
Data Memory Systems are asking whether Chromebooks really are the laptops of the future.
LITTLE multi-processing technology delivers the highest performance and efficiency across the widest range of workloads and it is a significant endorsement to see it used in the new Google Chromebook," said Nandan Nayampally, vice president of marketing, CPU group, ARM.
8226; Simple one-zip auto wake design that allows full access to Chromebook when open