Nickel: Properties, Reactions, Health and Environmental Impacts
Nickel: Properties, Reactions, Health, and Environmental Impacts
Chemical Properties of Nickel
Nickel (Ni), atomic number 28, is a hard, silvery-white, ductile, and malleable metal. Its atomic mass is 58.71. Nickel is primarily used in stainless steel and other corrosion-resistant alloys. It is also used in currencies as a silver substitute. Finely divided nickel serves as a catalyst for hydrogenation.
Chemical Reactions of Nickel
- Sodium Hydroxide (NaOH) Solutions: Forms a green nickel oxide precipitate,
Microorganism Cultivation and Isolation Techniques
Nutritive Agar for Undemanding Microorganisms
Peptone Water
Liquid culture medium for prior non-selective isolation of bacteria. Incubation: Approximately 18 hours at 37ºC.
Blood Agar, 6.8 pH
Isolation, cultivation, and identification of various bacteria.
Potato Dextrose Agar
Cultivation, isolation, and determination of the number of yeast and mold organisms. Incubation: Up to 5 days at room temperature.
Sabouraud Agar
Clear culture medium recommended for the cultivation of dermatophytes and the sensitivity
Read MoreNerve Signals, Muscle Control, and Synaptic Function
Nerve Membrane Potential and Nerve Transmission
General
All nerve signals are transmitted by nerve fibers, either in the brain, spinal cord, or peripheral nerves. These long nerve fibers are called axons. The axon is a tubular structure bounded by a cell membrane and filled with a liquid called axoplasm. Within the membrane of all nerve fibers, an electrical potential of about -90 millivolts exists. This is known as the membrane potential, generated by ionic concentration differences across the cell
Read MoreBacterial Structure, Types, and Functions
Bacteria are very simple organisms, classified as prokaryotes. Based on their shape, they can be categorized as:
- Rod-shaped bacilli
- Spherical cocci
- Spiral spirilla
- Comma-shaped vibrios
Bacterial Structure
Capsule
The capsule is a mucus layer that surrounds the bacterial wall, present only in some bacteria.
Function:
- Makes it difficult for antibodies and phagocytic cells of the host to recognize and destroy the bacteria.
- Facilitates the formation of colonies.
- Participates in exchange processes involving water,
Stem Cells, Genetic Engineering, and Infectious Diseases
Stem Cells and Transplants
ITEM 5. Who can donate? Usually, a person in a situation of brain death, or *encephalic* death. A person who has died and whose brain has stopped functioning, but whose heart is still beating artificially, can have their organs transplanted, as they are in perfect condition. In some types of transplants, the donor may be a living person (skin, bone marrow, kidney, etc.).
Immune Rejection
Our immune system can distinguish self from foreign. If white blood cells detect something
Read MoreHuman Body: Functions, Systems, and Anatomy
Living Things vs. Non-Living Things
Living things possess life and include animals, bacteria, and algae. They move, reproduce, and nurture relationships. These are the three vital functions.
- Heterotrophic Animal Nutrition
- Autotrophic Plant Nutrition: Photosynthesis
- Fungi: Heterotrophic nutrition (they are not plants because they acquire food by absorption, not ingestion)
All plants adapted to the air environment (not water) have a root, stem, and leaf. However, moss does not, as it represents an evolutionary
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