Aluminum is poorly absorbed following either oral or inhalation exposure and is essentially not absorbed dermally. The bioavailability of aluminum is strongly influenced by the aluminum compound and the presence of dietary constituents which can complex with aluminum and enhance or inhibit its absorption. Aluminum binds to various ligands in the blood and distributes to every organ, with highest concentrations found in bone and lung tissues. In living organisms, aluminum is believed to exist in four different forms: as free ions, as low-molecular-weight complexes, as physically bound macromolecular complexes, and as covalently bound macromolecular complexes. Absorbed aluminum is excreted principally in the urine and, to a lesser extent, in the bile, while unabsorbed aluminum is excreted in the faeces. Intake of some amount of nitrates and nitrites is a normal part of the nitrogen cycle in humans. In vivo conversion of nitrates to nitrites can occur in the gastrointestional tract under the right conditions, significantly enhancing nitrates' toxic potency. The major metabolic pathway for nitrate is conversion to nitrite, and then to ammonia. Nitrites, nitrates, and their metabolites are excreted in the urine. (L1137, L739)
The main target organs of aluminum are the central nervous system and bone. Aluminum binds with dietary phosphorus and impairs gastrointestinal absorption of phosphorus. The decreased phosphate body burden results in osteomalacia (softening of the bones due to defective bone mineralization) and rickets. Aluminum's neurotoxicity is believed to involve several mechanisms. Changes in cytoskeletal protein functions as a results of altered phosphorylation, proteolysis, transport, and synthesis are believed to be one cause. Aluminum may induce neurobehavioral effects by affecting permeability of the blood-brain barrier, cholinergic activity, signal transduction pathways, lipid peroxidation, and impair neuronal glutamate nitric oxide-cyclic GMP pathway, as well as interfere with metabolism of essential trace elements because of similar coordination chemistries and consequent competitive interactions. Aluminum can also interact with estrogen receptors, increasing the expression of estrogen-related genes and contributing to the progression of breast cancer. Certain aluminum salts induce immune responses by activating inflammasomes. Nitrate's toxicity is a result of it's conversion to nitrite once in the body. Nitrite causes the autocatalytic oxidation of oxyhemoglobin to hydrogen peroxide and methemoglobin. This elevation of methemoglobin levels is a condition known as methemoglobinemia, and is characterized by tissue hypoxia, as methemoglobin cannot bind oxygen. (A2450, L1613, L739, A235, A236)
来源:Toxin and Toxin Target Database (T3DB)
毒理性
致癌性证据
A4：未被分类为人类致癌物。/铝金属和不可溶性化合物/
A4: Not classifiable as a human carcinogen. /Aluminum metal and insouble compound/
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌物分类
摄入硝酸盐或亚硝酸盐，在导致内源性亚硝化的条件下，可能对人类具有致癌性（2A组）。
Ingested nitrate or nitrite under conditions that result in endogenous nitrosation is probably carcinogenic to humans (Group 2A). (L135)
Aluminum targets the nervous system and causes decreased nervous system performance and is associated with altered function of the blood-brain barrier. The accumulation of aluminum in the body may cause bone or brain diseases. High levels of aluminum have been linked to Alzheimer's disease. A small percentage of people are allergic to aluminium and experience contact dermatitis, digestive disorders, vomiting or other symptoms upon contact or ingestion of products containing aluminium. Nitrate and nitrite poisoning causes methemoglobinemia. Nitrites may cause pregnancy complications and developmental effects. They may also be carcinogenic. (L1137, L739, L740)
...No significant diferences were found in alumium uptake and distribution and its effect on lactate dehydragenase leakage and lactate formation when the metal ion was given as aluminum chloride, aluminum nitrate, or Al (lactate)3. Aluminum concentrations (AlCl2) >250 uM severely disturbed the determination of lactate dehdrogenase AST and lactate in a cell-free system. ...
Young (21 days old), adult (8 months), and old (16 months) rats were exposed to 50 and 100 mg aluminum/kg bw administered as aluminum nitrate in drinking water for a period of 6 months. Brain concentrations were found to be higher in young rats. Urinary aluminum levels of old rats tended to increase.
Following a single maximum safe oral dose of the water soluble compounds aluminum chloride (333 mg Al/kg), aluminum nitrate (934 mg Al/kg), aluminum citrate (1,081 mg Al/kg), and aluminum lactate (2,942 mg Al/kg) in rabbits, aluminum absorption was 0.57, 1.16, 2.18, and 0.63%, respectively.
Aluminium nitrate was administered in the drinking water of four groups of 10 female SD rats for one month at the following doses: 0, 375, 750, or 1500 mg/kg bw/day. Food and water consumption and urine volume were measured daily. Body weight and protein efficiency coefficients were calculated each week. On days 10, 20, and 30, blood was analyzed. At necropsy various tissues were sampled, examined histopathologically, weighed and aluminium content determined by atomic absorption spectrophotometry. Rats fed 1500 mg aluminium/kg bw/day excreted less urine (6 +/- 2 mL) than control rats (35 +/- 14 mL). There were no significant differences in relative organ weights between treated and control rats. Blood parameters were unchanged by aluminium treatment. Although tissue aluminium concentration was generally higher in treated animals the increases were only significant for spleen, heart, stomach and small and large intestine in rats receiving the highest aluminium concentration.
The production and selection of precursor mixtures used to produce fine powders and methods for making fine powders using the selected precursor. The precursor mixture comprises at least one metal containing precursor, the metal containing precursor has an average molecular weight of less than 2000 grams per unit mol of the metal, the metal containing precursor has a normal boiling point greater than 350K, and the viscosity of the precursor mixture is between 0.1 to 250 cP. The precursor mixture is processed under conditions that produce a fine powder from the precursor mixture. Fine powders produced are of size less than 100 microns, preferably less than 10 micron, more preferably less than 1 micron, and most preferably less than 100 nanometers.
Pyridine bases are produced in higher yield from at least one of aliphatic carbonyl compounds and ammonia by reaction at 350.degree. to 550.degree.C under the atmospheric pressure at a space velocity of 100 to 10,000 hr.sup.-.sup.1 in the presence of a catalyst prepared by immersing silica-alumina or a silica-alumina mixture containing a promoter in an aqueous solution of ammonium halide such as ammonium chloride, ammonium iodide or ammonium bromide at a concentration of not more than 20% by weight at room temperature to 80.degree.C, washing the immersed silica-alumina or the mixture with water, and drying and calcining the same at 300.degree.C or higher. Regeneration of the catalyst after the reaction can be carried out for a much shortened time.
Solutions of accelerator systems comprising a binary system comprising a) 10 to 90% by weight of a salt of formula I [Me].sub.m.sup.x.sym. [R].sub.n.sup.y.crclbar. (I), wherein x and y are the respective number of charges and m and n are each a number 1, 2, 3 or 4, Me is a metal atom and R is the radical of an alcohol, phenol or thiophenol or of a carboxylic acid or thiocarboxylic acid, or 10 to 90% by weight of a salt of formula II [Me.sub.1 ].sub.m.sup.x.sym. [A].sub.n.sup.y.crclbar. (II), with an organic complex former containing one or more hetero atoms having free electron pairs, wherein Me.sub.1 is a metal atom or a group of the formula N(R.sub.1).sub.4, S(R.sub.1).sub.3 or P(R.sub.1).sub.4 wherein each R.sub.1 independently of the others is hydrogen, an unsubstituted or substituted C.sub.1 -C.sub.6 alkyl or aryl radical, A is any anion and x, y, m and n are as defined above, and b) 90 to 10% by weight of an organic solvent containing at least one --OH, --OR.sub.1, --COOH, --COOR.sub.1, --COR.sub.1 or --CON(R.sub.1).sub.2 group wherein R.sub.1 is hydrogen, an unsubstituted or substituted C.sub.1 -C.sub.6 alkyl or aryl radical, are storage-stable with respect to temperature and time and do not precipitate, and the use thereof, for example for accelerating the hardening of epoxy resin/amine combinations, the drying times being in the range of about 15 to 40 minutes.
Lithium aluminate/zirconium material useful in the production of tritium
申请人：The United States of America as represented by the Department of Energy
公开号：US04475948A1
公开（公告）日：1984-10-09
A composition is described useful in the production of tritium in a nuclear eactor. Lithium aluminate particles are dispersed in a matrix of zirconium. Tritium produced by the reactor of neutrons with the lithium are absorbed by the zirconium, thereby decreasing gas pressure within capsules carrying the material.
A method for producing α-alumina powder is described. The method comprises the steps of removing water from a compound containing the following (1), (2), (3) and (4), and calcining the results: (1) α-alumina precursor, (2) seed crystal, (3) water, (4) nitrate ion in an amount of from 2.8 to 3.3 mol per mol of aluminum (Al) contained in the α-alumina precursor and the seed crystal.
