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Holmium metal
Holmium alloy
Holmium powder
Holmium granule
Holmium is a metallic element with chemical symbol Ho, atomic number 67 and atomic weight 164.93. The element name comes from the birthplace of the discoverer. In 1878, Sorit discovered holmium from the spectrum of erbium soil, and the following year, Clive in Sweden separated holmium from erbium soil by chemical method. Holmium has a content of 0.000115% in the earth's crust and is found in monazite and rare earth minerals along with other rare earth elements. The natural stable isotope is holmium 165 only. Holmium is a silver-white metal, soft and malleable. Melting point 1474°C, boiling point 2695°C, density 8.7947 g/cc. Holmium is stable in dry air and oxidizes quickly at high temperature. Holmium oxide is the most paramagnetic substance known. Holmium compounds can be used as additives for new ferromagnetic materials. Holmium iodide is used to make metal halogen lamps -- holmium lamps. Holmium laser is also widely used in the medical field
Holmium Ho is a rare earth element, and its main uses are [2] :
(1), used as an additive for metal halogen lamp, metal halogen lamp is a kind of gas discharge lamp, it is developed on the basis of high-pressure lamp, its characteristics are filled with a variety of rare earth halides in the bulb. The main use is rare earth iodide, which emits different spectral line light colors when the gas is discharged. Holmium iodide is used as the working substance in the holmium lamp, which can obtain a higher concentration of metal atoms in the arc zone, thus greatly improving the radiation efficiency.
(2) holmium can be used as an additive of yttrium iron or yttrium aluminum garnet;
holmium
holmium
(3) Yttrium aluminum garnet doped with holmium :YAG (Ho:YAG) can emit 2μm laser, and the absorption rate of 2μm laser in human tissue is almost 3 orders of magnitude higher than Hd:YAG. Therefore, when Ho:YAG laser is used for medical operation, it can not only improve the efficiency and accuracy of operation, but also reduce the thermal damage area. The free beam produced by holmium crystals can eliminate fat without generating excessive heat, thus reducing thermal damage to healthy tissue. It has been reported that holmium laser treatment for glaucoma in the United States can reduce the pain of surgery for patients. The level of 2μm laser crystal in China has reached the international level, so great efforts should be made to develop and produce this kind of laser crystal.
(4) In magnetostrictive alloy Terfenol-D, a small amount of holmium can also be added to reduce the external field required by the saturation magnetization of the alloy [3].
(5) In addition, holmium doped fiber can be used to make fiber laser, fiber amplifier, fiber sensor and other optical communication devices in today's rapid fiber communication will play a more important role.
Holmium laser
Holmium laser drilling
Holmium laser drilling
Holmium laser lithotripsy [4] : Medical holmium laser lithotripsy is suitable for hard kidney stones, ureteral stones and bladder stones that cannot be broken by extracorporeal shock wave lithotripsy. In medical holmium laser lithotripsy, the slim optical fiber of medical holmium laser reaches the bladder stone, ureteral stone and kidney stone through urethra and ureter with the help of cystoscope and ureteral soft mirror, and then urological experts manipulate the holmium laser to break the stone. The advantage of this treatment is that it can resolve ureteral stones, bladder stones and most kidney stones. The disadvantage is that for some calculi of the upper and lower renal calyces, a small amount of calculi may remain because the holmium laser fiber entering from the ureter cannot reach the calculi site.
Holmium laser is a new laser produced by pulsed solid laser device which is made of yttrium aluminum garnet (YAG) as activation medium and doped with sensitized ion chromium (Cr), energy-carrying ion thulium (Tm) and activator ion holmium (Ho) laser crystal (Cr:Tm:Ho:YAG). It can be used in urology, ent, dermatology, gynecology and other departments. The laser procedure is non-invasive or minimally invasive, and the patient is treated with very little pain.
Storage method editor broadcast
Store in a cool, ventilated warehouse. Keep away from fire and heat. It should be stored separately from oxidizers, acids, halogens, and do not mix storage. Explosion-proof lighting and ventilation facilities are adopted. Do not use mechanical equipment and tools that are prone to spark. The storage area should be equipped with suitable materials to contain leaks.
The poison editor reports
cytotoxicity
The toxicity of holmium nitrate is easily detected at cellular and subcellular levels [2]. It has been shown that the root tips of broad bean were treated with holmium nitrate at concentrations higher than 4mg/L. That is, it can cause root tip texture hardening, color darkening, growth slowing, cell division index decline and other phenomena, and with the increase of dose or prolonged exposure time, the degree of damage to root tip cells showed an aggravating trend. It was also observed that the nuclei were condensed and deeply stained, the nucleolus particles were reduced, the nucleolus and nucleolus were not clear, and the cells were aggregated into clumps. Progressive tissue fibrosis and other phenomena. Similar results have been seen in vivo in animal studies when dosages are used. Holmium nitrate inhibited the proliferation of bone marrow cells in mice treated with 20mg/kg body weight. In addition, abnormalities such as lymphocyte nucleus condensation, hyperstaining, fragmentation, chromatin boundary set, protrusion, and indention were also observed under the microscope, and the degree and proportion of nuclear abnormalities increased with the increase of dose. All these indicated that holmium nitrate had a certain toxic effect on cells, which was consistent with the reported toxicity of lanthanum, cerium, erbium and 14 other rare earth elements.
Biochemical toxicity
Animal experiments have found [2] that holmium nitrate can improve the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) under a certain dose, and can remove excess superoxide anion free radicals (O2-·) and inhibit lipid peroxidation. The activities of SOD, POD and CAT in the liver of mice increased when the dosage of holmium nitrate was low (10-40mg/kg body weight), and the activities of the three antioxidant enzymes were inhibited when the dosage reached 80 and 160mg/kg body weight. These results indicate that low dose holmium can reduce the oxidative damage of free radicals to biomacromolecules and cells, but high dose holmium can reduce the activity of antioxidant enzymes, so that free radicals accumulate in the body and destroy the structure and function of cells, leading to mutations, indicating that holmium has a certain mutagenic effect at high dose.
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