... Carp (Cyprinus carpio) /were held/ for 48 hr in lead nitrate concn of between 0 and 20 mg lead/L, with and without one of the three complexans, EDTA, NTA, or DTPA. The accumulation of lead in both viscera and gills was dose-related, with the highest levels for viscera and gills being 86,000 and 4,560 mg/kg dry wt, respectively. The complexans reduced the uptake of lead at all dose levels. Concn in viscera ranged from 399 to 690 mg/kg for the three complexans, and 298 to 645 mg/kg in gills, after exposure to 20 mg/Lead (which had given the above levels without chelating agents).
Lead is absorbed following inhalation, oral, and dermal exposure. It is then distributed mainly to the bones and red blood cells. In the blood lead may be found bound to serum albumin or the metal-binding protein metallothionein. Organic lead is metabolized by cytochrome P-450 enzymes, whereas inorganic lead forms complexes with delta-aminolevulinic acid dehydratase. Lead is excreted mainly in the urine and 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, L136)
Lead mimics other biologically important metals, such as zinc, calcium, and iron, competing as cofactors for many of their respective enzymatic reactions. For example, lead has been shown to competitively inhibit calcium's binding of calmodulin, interferring with neurotransmitter release. It exhibits similar competitive inhibition at the NMDA receptor and protein kinase C, which impairs brain microvascular formation and function, as well as alters the blood-brain barrier. Lead also affects the nervous system by impairing regulation of dopamine synthesis and blocking evoked release of acetylcholine. However, it's main mechanism of action occurs by inhibiting delta-aminolevulinic acid dehydratase, an enzyme vital in the biosynthesis of heme, which is a necesssary cofactor of hemoglobin. 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, T4, A20, A22, L136)
来源:Toxin and Toxin Target Database (T3DB)
毒理性
致癌性证据
无法评估...硝酸铅的致癌性。
No evaluation could be made of the carcinogenicity of ... lead nitrate.
来源:Hazardous Substances Data Bank (HSDB)
毒理性
致癌性证据
铅、铅化合物：合理预期为人类致癌物
Lead, lead compounds: Reasonably anticipated to be a human carcinogen
A3; Confirmed animal carcinogen with unknown relevance to humans. /Lead, elemental, and inorganic compounds, as Pb/ American Conference of Governmental Industrial Hygienists TLVs and BEIs.
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，对人类可能是致癌的（2A组）。
Ingested nitrate or nitrite under conditions that result in endogenous nitrosation is probably carcinogenic to humans (Group 2A). (L135)
The retention and tissue distribution of (210)Pb were studied on 10-day-old, 150-day-old, and adult Macaca fascicularis monkeys, each age-group comprising four animals ... Lead nitrate, 10 ug lead/kg bw, containing 10 u-Ci (210)Pb/ug Pb was administered by gavage after a 12-hr fast. The (210)Pb excreted in urine and feces was monitored for 96 hr. All monkeys were necropsied 96 hr after dosing, and the (210)Pb contents of various tissues was determined. The data demonstrate that infant monkeys retain significantly more lead than adults. Blood (210)Pb levels 96 hr after dosing did not vary significantly between age groups, and of the (210)Pb contained in blood, 98-99% was found in the cells, and 1-2% in the plasma. In the cells, 5-8% of the (210)Pb was bound to the cell membranes. The distribution between blood components did not vary significantly with age. The percentage of the lead dose excreted in urine did not vary significantly between age groups. Both the tissue Pb concn and tissue-blood Pb ratios were significantly higher in the bone structures of the young animals than in the adults. The brain:blood Pb ratio in the infants was significantly higher than in the older groups.
来源:Hazardous Substances Data Bank (HSDB)
吸收、分配和排泄
在禁食条件下，硝酸铅、硫化铅和铅胱氨酸的吸收率在16%到53%之间。
... Under fasting conditions absorption of lead nitrate, lead sulfide, and lead cysteine ranged from 16 to 53%.
Much of an oral dose of (203)Pb lead nitrate was poorly absorbed and thus ... excreted fairly rapidly from the lactating cow. In 6 days, 95% ... excreted in ... feces, 0.2% in ... urine, and 0.02% in the milk. The biological half lives were 18 hr for the unabsorbed and 72 hr for ... absorbed (203)Pb.
来源:Hazardous Substances Data Bank (HSDB)
吸收、分配和排泄
铅对骨骼有特别的亲和力，在大鼠接受硝酸铅处理后4天，其骨骼中的铅含量比软组织高出七倍。
Lead had a particular affinity for bone which, in rats 4 days after lead nitrate treatment, contained sevenfold more lead than the soft tissue.
Oxidation of organic compounds having benzylic carbon atoms in water
申请人：Allied-Signal Inc.
公开号：US05171880A1
公开（公告）日：1992-12-15
The present invention is directed to a process of oxidizing organic compounds having benzylic carbon atoms. The process of this invention comprises reacting an organic compound having one or more benzylic carbon atoms with an effective amount of an effective oxidizing agent in water at a temperature equal to or greater than about 350.degree. C. and at a pressure equal to or greater than about 175 atmospheres, wherein said agent is selected from the group consisting of a combination of one or more bases and one or more of elemental sulfur, an oxidized form of elemental sulfur and/or an organic or inorganic sulfur containing compounds capable of forming elemental sulfur, said oxidized forms or a combination thereof in situ under process conditions, and organic or inorganic compounds which form one or more bases and elemental sulfur, oxidized forms of sulfur or a combination thereof in situ under process conditions.
A method of producing explosive for priming explosive devices by reacting components in situ in a device.
一种通过在装置中原位反应组分以制备引爆装置的爆炸物的方法。
Preparation of titanates
申请人：Murata Manufacturing Co., Ltd.
公开号：US04061583A1
公开（公告）日：1977-12-06
A process for the preparation of a titanate which comprises adding an aqueous solution containing ions of titanium and at least one metal selected from the group consisting of Ba, Ca, Sr, Zn, Cd and Pb to an aqueous alkaline solution containing hydrogen peroxide, recovering the resulting precipitate and heating the precipitate at a temperature not lower than 100.degree. C to give the titanate of the metal as used in uniformly fine particles. The resulting titanate can be used as ceramic materials for electronic elements.
An indicator element which provides a visual indication when subjected to correct steam sterilization conditions in an autoclave, the element comprising a substrate having coated thereon an ink formulation comprising as the primary visual change component: (i) a sulfur-containing compound capable of decomposition to yield a metal sulfide under steam sterilization conditions, or (ii) the precursors of which a sulfur-containing compound which will yield said sulfur-containing compound under aqueous conditions.
Ceramic oxide powder, method for producing the ceramic oxide powder, ceramic paste produced using the ceramic oxide powder, and method for producing the ceramic paste
申请人：Samsung Electro-Mechanics Co., Ltd.
公开号：US06319421B1
公开（公告）日：2001-11-20
A method for producing ceramic oxide powder having a grain size of 5 &mgr;m or less and exhibiting a uniform grain size distribution is disclosed. The method includes the steps of sufficiently dissolving or uniformly dispersing a raw material of constituent ceramic elements in a solvent or dispersion medium, thereby preparing a solution or dispersed mixture containing the constituent ceramic elements, adding citric acid in the solution or dispersed mixture, in which the constituent ceramic elements are dissolved or dispersed, at least in an amount required to generate an oxidative-reductive combustion reaction with anions of the constituent ceramic elements, thereby preparing a mixed solution, and thermally treating the mixed solution at a temperature of 100 to 500° C., thereby evaporating the solvent or dispersed medium while causing the citric acid to act as a reductive combustion aid, thereby generating a non-explosive oxidative-reductive combustion reaction with the anions of the constituent ceramic elements, so that ceramic oxide is produced without any scattering by virtue of heat generated during the combustion reaction. Using the ceramic oxide powder, ceramic paste having a micro grain size and exhibiting a superior reaction property can be produced using a single combustion process at a low temperature.
