月: 2023年1月

What Is a Pipette?

A pipette is a laboratory apparatus used to suck out a desired amount of liquid and transfer it to a container or other medium.

A pipette is used in a wide range of fields, from natural sciences such as chemistry and biology to applied sciences such as medicine and pharmacy. There are several types of pipettes, and they are used for different purposes. The two main materials used are glass and plastic.

Glass pipettes have excellent chemical and heat resistance and can be reused by washing or dry heat sterilization. Plastic pipette is less resistant to chemicals and heat than glass pipette. However, they are inexpensive and disposable, saving time and effort in cleaning and preventing contamination.

A similar product to a pipette is a dropper. While droppers are made of plastic and a fixed amount is sucked in, a pipette is made of plastic or glass and comes in various types, depending on the product. Some pipettes have attachments that allow the user to adjust the amount to be aspirated depending on the attachment and settings.

Uses of Pipettes

Pipettes are mainly used for the following two purposes:

• Measuring liquids (liquid dispensing)
• To transfer a liquid to another container (liquid transfer)

The pipettes used differ depending on the purpose. Therefore, it is necessary to select pipettes in consideration of the intended use.

Principle of Pipettes

A micropipette consists of a tip holder, a grip, a push button, and a volume-setting dial.

The amount of liquid to be aspirated is adjusted by operating the liquid volume setting dial, and the push button moves the internal piston to change the amount of air, thereby aspirating and dispensing the liquid (air displacement method). There is a circular rubber O-ring inside that allows the internal piston to move while maintaining an airtight seal.

There is also a spring inside, and the push button is automatically returned by the force of the spring to enable aspirating and dispensing of liquid.

Types of Pipettes

There are various types of pipettes, and it is important to select the appropriate one. The usage also differs depending on the type.

1. Pipettes for Liquid Sampling

Hole Pipettes
Hole pipettes are instruments used to accurately measure liquids. The center of the glass tube is distended, and a graduation line is drawn on the top. The pipettes are finely made and can measure liquids with a very high degree of accuracy.

The tip of the pipettes is dipped into the liquid, and the liquid is put into the glass capillary as if sucking it through a straw. However, nowadays, to prevent accidental ingestion of dangerous reagents when sucking, rubber safety pipettes or auto pipettes are often attached to the top to aspirate and dispense the liquid.

Female Pipettes
Female pipettes are another instrument for accurately measuring liquids. They are made of glass or plastic and are graduated throughout the pipettes. Like hole pipettes, it has rubber safety pipettes or auto pipettes attached to the top to aspirate and dispense liquid.

Micropipette
Micropipettes are instruments for measuring liquids in microliters. To use micropipettes, first turn the dial to set the amount of liquid to be aspirated. Next, grasp the grip with your dominant hand and place your thumb on the push button at the top.

Attach a tip of the appropriate size to the end of the tip holder and fit it securely. Then press the push button to aspirate and dispense the liquid. Finally, press the ejector button near the push button to remove the tip. 

2. Pipettes for Transferring Liquid

Komagome Pipettes
Komagome pipettes are used when you want to transfer a liquid to another container. It is similar in shape to an eyedropper but is often made of chemical-resistant glass or other materials designed for use with chemicals. A rubber ball is attached to the top to aspirate and dispense liquid.

Pasteur Pipettes
Pasteur pipettes are glass pipettes with long, thin tips for aspirating liquid. Since Pasteur pipettes do not have a scale, they are often used to transfer small amounts of liquid and are basically disposable. As with Komagome pipettes, a rubber ball is attached to the top, to aspirate and dispense liquid.

What Is a Fine Ceramic?

Materials in the world can be broadly classified into three categories: metallic materials, organic polymer materials, and ceramics. Among these, ceramics are characterized by their high hardness and thermal and chemical stability. Conventional ceramics are called old ceramics and are formed by mixing or firing natural minerals in glass, cement, ceramics, etc. A fine ceramic is made based on chemical processes.

Fine ceramics are defined by their superior mechanical, electronic, physical, and chemical properties, as well as enhanced functionality compared to traditional ceramics, due to precise control of their chemical composition, crystal structure, and particle shape in the manufacturing process. Fine ceramic is said to have originated in 1940 when the application of ceramics to industrial products and the development of new functions began to flourish.

Uses of Fine Ceramics

Fine ceramics are used in a wide range of fields as structural, electronic, engineering, biological, and magnetic materials. For example, they are used in electronic components, industrial equipment, medical devices, and other equipment necessary for manufacturing operations.

In semiconductor and liquid crystal manufacturing equipment, wafers, which are used as elements, are processed using fine ceramics to secure them to the equipment and polish the surfaces.

In medical equipment, fine ceramics are used for surgical instruments, implant parts, and X-ray insulating parts for radiation equipment.

In addition to the above, fine ceramics are applied in information equipment, environmental, energy, aerospace, and electronics industry components.

Characteristics of Fine Ceramics

Fine ceramics are difficult to define but are often defined as “mainly non-metallic inorganic materials” with new functions or properties that are manufactured by precisely controlling their chemical composition, crystal structure, microstructure, grain boundaries, shape, and manufacturing process.

The manufacturing process for fine ceramics begins with the preparation of raw materials, followed by granulation, molding, raw processing, firing, secondary processing, and inspection.

Fine ceramics are made by mixing raw material powders that are more granular or purer than ordinary ceramics, and then using precision equipment to control the structure at the micro to nano level. Fine ceramics are especially useful inside industrial equipment, where heat can easily build up because their thermal properties are superior to those of metals and organic materials.

On the other hand, the disadvantage of fine ceramics is that they are brittle and difficult to process. Because they are formed from powdered raw materials, even a simple drop from a high place can cause them to crack with the impact. This also makes it difficult to process Fine Ceramics into other shapes once they have been formed into one shape.

Types of Fine Ceramics

Fine ceramics can be broadly classified into two types. The first is engineering ceramics, to which a sintering process is added. These ceramics can only be ground and polished, but they have excellent wear resistance. Materials include alumina, silicon nitride, and zirconia.

On the other hand, machinable ceramics are those to which no sintering process is added, and although their strength is weaker than engineering ceramics, they can be machined. Fine ceramics include Hortobell, Macerite, and Makor.

Fine ceramics are also available in a variety of materials, each of which has different properties. Here are some typical ceramic materials.

Alumina (AI2O3)

Alumina is aluminum oxide and is the most common ceramic material. It is characterized by excellent electrical insulation, wear resistance, heat resistance, and chemical stability while being extremely inexpensive.

Zirconia (ZrO2)

Zirconia has excellent strength and toughness and is sometimes used in combination with metals because its thermal expansion coefficient is close to that of metals. It is also used in blades such as scissors, which is difficult to do with ceramics.

Silicon Carbide(SiC)

Silicon carbide is a man-made compound that does not exist naturally; it has excellent strength even at temperatures as high as 1500°C. It is also lightweight and highly corrosion-resistant. Because of these characteristics, it is used as a heat-resistant material in applications such as heater peripheral parts.

There is a wide variety of other types of fine ceramics, including special ceramics such as porous ceramics and transparent ceramics. It is important to select fine ceramics with appropriate materials and properties for the environment in which they will be used.

What Is a Fan Coil Unit?

A fan coil unit is a device for air conditioning that generally consists of a heat exchanger (coil), air filter, and fan motor unit.

Cold or hot water sent from the main unit through piping is used to adjust room temperature and humidity through the heat exchanger, and dust is removed by the air filter and sent to the air conditioning area by the fan motor unit.

This is a relatively small and simple air conditioning unit and is also called a fan convector, especially in the case of a dedicated heating unit.

Uses of Fan Coil Units

They are generally installed and used in offices, hotels, hospitals, schools, and large commercial facilities. The most common type of fan coil unit is a square vent air conditioning unit installed in the ceiling of each room.

Fan coil units are mainly used for indoor temperature control, while the air conditioning unit (AHU) is used to communicate with the outside air. The air conditioning and heating systems for the entire building are unified and are often used for overall air conditioning purposes rather than for individual needs.

Principle of Fan Coil Units

Air conditioners consist of an indoor air conditioning unit and an outdoor unit accompanied by a fan, which operates in pairs, and each air conditioner is used for different purposes such as cooling, heating, and dehumidification. On the other hand, the fan coil unit air-conditions cold or hot water sent from the main unit through piping via heat exchangers in each room unit, so the type of air-conditioning for the entire building is determined.

They are often used in large commercial facilities, hotels, hospitals, etc., where the purpose of air conditioning the entire building is fixed and can provide heating and cooling more efficiently and economically through centralized control than by installing individual air conditioners in each room.

Recently, fan coil units have been used in combination with air conditioners, taking advantage of their compactness and simplicity. The fan coil unit performs load control in the perimeter zone near exterior walls and windows, while the air conditioner performs temperature control in the interior zone.

Types of Fan Coil Units

Fan coil units are available in 2-tube, 3-tube, 4-tube, standard motor-equipped, and energy-saving motor-equipped types.

1. 2-Tube Type

With only one coil, the cooling and heating water is switched as necessary between the heating and cooling seasons. It is relatively inexpensive, requires fewer pipes, and takes up less space.

2. 3-Pipe Type

This type has a hot water coil and a cold water coil and has only one cold and hot water return pipe.

3. 4-Pipe Type

There is a hot water coil and a cold water coil, and the number of pipes is large. It is used in rooms that need to switch between heating and cooling during the day. It is finely adjustable, but more expensive to install and operate than 2-pipe or 3-pipe systems.

4. Standard Motor-Equipped Type

This type is equipped with an AC motor and can be installed according to the space and application of the building. The main installation methods include floor-mounted type, ceiling-suspended type, ceiling-recessed type, and ceiling cassette type.

5. Energy-Saving Motor-Equipped Type

This type is equipped with a DC brushless motor. The environmentally friendly energy-saving motor reduces carbon dioxide (CO2) emissions, and the low air volume saves power consumption and reduces running costs. Installation methods include floor-mounted exposed type, floor-mounted concealed type, ceiling-suspended concealed type, and cassette type.

Structure of Fan Coil Units

Fan coil units are available in a variety of configurations, including double-floor-blowout, duct-connected, wall-mounted, floor-mounted, ceiling-suspended, and ceiling-mounted cassette types.

1. Double-Floor Blowout Type

Warm or cold air is blown out from inside the double-floor unit and is used in double-floor rooms such as computer rooms.

2. Duct Connection Type

The unit can be connected to ducts and installed in any desired location.

3. Wall-Mounted Type

This type is mounted on the wall.

4. Floor-Mounted Type

This type is used by placing it on the floor.

5. Ceiling-Suspended Type

This type is used in warehouses and other locations where the ceiling framework is exposed.

6. Ceiling-Mounted Cassette Type

Installed in the ceiling, this type has an outlet and an intake on the surface.

What Is a Pulley?

Pulleys are mechanical parts that transmit rotational force from shaft to shaft via a belt. There are various shapes and types of pulleys. The belt and pulley are used in combination with other pulleys of the same type. There are pulleys for flat belts, V-belts, toothed pulleys, round belts, metal belts, etc., and there are belts that match each type of pulley. There are also a number of belts manufactured according to the manufacturer’s own specifications.

Uses of Pulleys

Flat belt pulleys have high transmission efficiency and are used for power transmission in agricultural machinery and for paper transport in office automation equipment.

Pulleys for V-belts are resistant to high loads and can be used to apply multiple belts side by side. They are used for power transmission in drilling machines, automobile engines, dust collectors, etc.

Toothed pulleys are used in places where slippage is not desired. They are used in equipment that performs high-precision and precise positioning and conveyance by servomotors and stepping motors, printer equipment, etc.

Pulleys for round belts are not suitable for high loads. However, they have a high degree of freedom and are used in toys, office automation equipment, etc.

Principle of Pulleys

As mentioned above, pulleys transmit rotational force in combination with belts. There are two methods of transmission: friction transmission and meshing transmission.

Pulleys for flat belts, V-belt pulleys, and round belt pulleys are friction motors, which transmit rotational force by the frictional force of the contact surface between the pulleys and the belt. The transmission force is greater than that of a flat belt pulley. Slip is inevitable in friction transmission, and it is used in situations where it is tolerated. However, in some cases, friction transmission is considered to work as a safety device, taking advantage of the fact that the pulleys and belts slip and spin when an excessive load is applied. For example, when something is caught in the drive system, slipping prevents overloading by preventing a certain amount of force from being applied.

Toothed pulleys are an engaged transmission. The pulleys and belts have teeth that engage with each other to transmit power, so slippage does not occur. Therefore, it is used in situations where high-precision positioning is required. Sprockets and chains are similar mechanical components, but toothed pulleys are lighter, quieter, and require less lubrication.

What Is a Forklift?

Forklifts are equipment developed to improve the efficiency of cargo transport operations.

It has forks to insert into a pallet and a mast to raise and lower the pallet and is operated by hydraulic or electric power.

Forklift operation requires safety precautions to prevent tipping over and collisions, and requires completion of a prescribed skills training course. When transporting goods, they can be loaded on pallets with holes in the sides and lifted by pointing the forks at the holes.

Uses of Forklifts

Forklifts are used in factories and distribution warehouses to improve the efficiency of cargo handling operations. Forklifts are used to quickly move loads that are difficult to lift by hand.

In recent years, batteries have become the main power source for forklifts, due to their lower exhaust emissions and improved operability. Forklifts are designed to be maneuverable, but smaller, non-powered handlifts are used for moving and transporting in confined spaces.

Principle of Forklifts

The part of the forklift that lifts and carries the load is called the load handling unit, which operates mainly by hydraulic pressure. When high-pressure hydraulic fluid is fed into the cylinder, the cylinder of the load handling unit is moved to lift the load, and when the load is lowered, the hydraulic fluid is returned to the tank to lift and tilt the forks.

A standard load is specified for the weight that can be carried with the forks lifted to a certain height, but when the forks are lifted higher for use, it is important to limit the load capacity in consideration of the center of gravity. The maximum load according to height is indicated on the lift as the allowable load.

It is important to always pay attention to the position of the center of gravity when operating the lift. Carrying a load in excess of the allowable load capacity or tilt operation with the forks raised high is prohibited because the center of gravity will move forward and upward, causing the lift to tip over. When traveling uphill, the forks should be moved forward and backward.

Types of Forklifts

Forklifts are mainly classified into five types

1. Counter Lift

This is the most common type of forklift and is constructed to withstand heavy weights. Weights are installed at the rear of the vehicle body to maintain equilibrium when lifting and carrying heavy objects. The vehicle body is stable, can be operated from a seated position, and the forklift is fast. However, the vehicle body is large and is not suitable for use in confined spaces.

2. Reach Forklift Truck

The forks can be moved back and forth without moving. Operated from a standing position, the forks can be pulled inward regardless of the weight of the load. Tires rotate 90°, making it easy to maneuver indoors and in other confined spaces.

3. Side Forklift

The forks are located next to the vehicle body, and the operator’s seat is high. It has a wide cargo bed and is suitable for transporting long items such as pipes and lumber.

4. Walkie Forklift Truck

It can be moved by hand while the operator walks without getting into the vehicle. Since it is electrically powered, it does not require much force to move by hand. Its compact size allows it to move in narrow aisles, and it can be loaded and unloaded in an elevator.

5. Multi-Directional Forklift

The forklift can move not only forward and backward but also sideways. Because it can move sideways, it does not need to turn around in narrow aisles.

Structure of Forklifts 

Forklifts are powered by either storage batteries or internal combustion engines.

1. Battery-Powered

The electricity stored in the battery powers the motor. Battery-type storage batteries have been widely used in forklifts since early times. At present, battery-type forklifts are often used in small forklifts of 3 tons or less.

Battery-powered forklifts make little noise and are suitable for working in residential areas late at night or early in the morning. They are environmentally friendly as they do not emit exhaust gases and are safe even in closed areas such as refrigerated warehouses.

2. Internal Combustion Engine Type

This type uses gasoline, compressed natural gas, liquefied petroleum gas, or diesel as fuel. Diesel is often used when power is more important than speed. However, exhaust fumes pose a health risk and they cannot be used in enclosed areas.

What Is Saccharin?

Saccharin is an organic compound used as an artificial sweetener. It has the chemical formula C7H5NO3S and is composed of a benzene ring fused to a sultam ring. It is also known as o-sulfobenzimide and o-benzoic acid sulfimide, and other names.

It has a molecular weight of 183.18 and a melting point of 228.8° C. At room temperature, it is in the form of clear, colorless crystals or a white powder.

It has a slight aromatic odor. It has a density of 0.828 g/cm3 and an acid dissociation constant pKa of 1.6. It is soluble in ethanol and acetone and slightly soluble in water.

Uses of Saccharin

The main use of saccharin is as a sweetener. It has a sweetness of 200-700 compared to sucrose, which has a sweetness of 1, even in a 10,000-fold aqueous solution.

Saccharin itself is used only in limited foods such as chewing gum due to its low water solubility, and sodium saccharin, a water-soluble sodium salt, is generally used in a variety of processed foods.

Sodium saccharin is also used in medicines and foods where there is a need to prevent spoilage due to sugar, such as toothpaste, gum, pickles, and confections. It is a substance that is not readily absorbed by the body because it contains no glucose when broken down, and has a smaller energy intake than sucrose and other sugars.

It is used as an alternative to sugar in diabetics and other diets where sweetness is restricted, and in diet foods and beverages.

Properties of Saccharin

Aqueous solutions of saccharin are 350 times sweeter than sucrose, or 200-700 times sweeter, and have a numbing, pungent aftertaste. However, at high concentrations, it is said to have a bitter taste.

The substance is stable under normal storage conditions. However, it may be altered by light, and contact with strong oxidizing agents should be avoided. Hazardous decomposition products include carbon monoxide, carbon dioxide, nitrogen oxides, and sulfur oxides.

Types of Saccharin

Saccharin is sold as a reagent product for research and development and as a sweetener and food additive raw material.

As reagent products for research and development, saccharin is sold as sodium saccharin hydrate as well as saccharin alone, in capacities of 25 g, 500 g, etc. Both are usually sold as reagent products that can be stored at room temperature. In research, their applications include physiological research and raw materials for organic synthesis.

Most sweetener and food additive raw material products are sold as sodium saccharin. Most of the capacity types are relatively large capacities such as 1 kg x 20 /carton. Saccharin is supplied for industrial use, such as in factories.

Other Information on Saccharin

1. Synthesis of Saccharin

Saccharin was accidentally discovered in 1878 from the study of coal tar. Many synthetic methods have been reported.

Originally, it was synthesized from toluene (one of the components of coal tar), but the yield was low, and in 1950, an improved synthetic method was reported in which methyl anthranilate is sequentially reacted with nitrous acid, sulfur dioxide, chlorine, and ammonia.

Other synthetic methods include a synthetic reaction using 2-chlorotoluene as a raw material.

2. Safety of Saccharin

Saccharin was banned for a period of time in the 1970s because the results of animal testing suggested a carcinogenic risk. The ban was later withdrawn because various tests conducted thereafter did not confirm carcinogenicity.

Because of this regulatory history, saccharin has been replaced in many foods by other artificial sweeteners such as sucralose, acesulfame potassium, and aspartame.

What Is Coal Tar Pitch?

Coal tar pitch is a substance derived from the fractional distillation of coal tar. It appears as a sticky, dark brown or black liquid with a strong aroma.

Coal tar pitch is recognized as a health risk and is classified as carcinogenic. In 2010, the International Agency for Research on Cancer (IARC) concluded, based on epidemiological studies, that there is sufficient evidence that occupational exposure to coal tar pitch during road paving and roofing operations is carcinogenic to humans. Skin tumors, including skin cancer, have also been observed in experimental animals like mice. Due to this evidence, coal tar pitch is classified as Group 1 in the IARC’s carcinogenicity classification.

Uses of Coal Tar Pitch

Coal tar pitch is utilized as a carbon material, binder, waterproofing agent, and rust inhibitor. When subjected to dry distillation, coal tar pitch yields pitch coke, a black carbonaceous material that serves as the raw material for specialty carbon products. Pitch coke is used as an electrode material in aluminum refining, as a carburizer in electric steelmaking furnaces, and in the production of special carbon products for semiconductors.

Pitch coke is also blended with coking coal as a binder in the production of casting coke, which requires strength during heat generation.

What Is Coal Tar?

Coal tar is a liquid substance obtained from the dry distillation of coal by cooling a hot gaseous substance.

There are two types of coal tar: low-temperature coal tar produced by low-temperature distillation and high-temperature coal tar produced by high-temperature distillation. Low-temperature coal tar is generally used.

It is basically a mixture of various aromatic hydrocarbons, and its CAS registration number is 8007-45-2.

Coal Tar used to be obtained as a byproduct of coal dry distillation in the production of city gas. However, since the raw materials for city gas have shifted to natural gas, coal tar is now produced as a byproduct of coke production for steelmaking at steel mills.

Uses of Coal Tar

The main uses of coal tar are as a raw material for tar distillation products, anti-corrosion paint, fishing net dye, oil smoke, and fuel.

In the past, it was widely used as a preservative for wood such as sleepers and wooden poles, and as a coating for tin roofs, but its use has declined in recent years due to changes in building materials and the widespread use of concrete.

It was also used as a support material for carbon electrodes.

Coal tar preparations also used to be a substance used in medicine because of its keratolytic, plasmolytic and antipruritic properties. In particular, psoriasis, a type of skin disease, was once treated with the Geckelman therapy, in which coal tar was applied externally. However, since its carcinogenicity, which will be discussed later, it is no longer used.

Tar Distillation Products

Coal tar is used as a raw material for distillation to produce tar distillate products. Tar light oil, a relatively light fraction of the fractional components, is used for BTX (benzene, toluene, and xylene) and styrene monomer.

Carbol oil and naphthalene oil are used for phenol and cresol.

Anthracene oil is used for carbon black and pitch is used for pitch coke.

Properties of Coal Tar

The main components of Coal Tar are polycyclic aromatic hydrocarbons.

The main compounds and their content are as follows:

• Naphthalene: 5%-15
• Benzene: 0.3%-1
• Phenol: 0.5%-1.5
• Benzo[a]pyrene: 1%-3
• Phenanthrene: 3%-8

It is brown or black in color, viscous liquid. It has a peculiar naphthalene-like odor. Its specific gravity is 1.18-1.23. It is slightly soluble in water and mostly soluble in benzene and nitrobenzene.

It is also partially soluble in some alcohols and caustic soda solutions.

Types of Coal Tar

Coal tar is sold as a corrosion inhibitor for various steel products, as a wood preservative, and as a reagent product for research and development.

As an anticorrosion and corrosion inhibitor, the product is available in 16 kg, 2.5 kg, and other capacities. As R&D products, they are available in capacities of 100 mL, 500 mL, etc.

Coal tar is also fractionated by distillation and sold as tar fractionated products. The main products and their applications are as follows:

• Pitch: binder for electrodes
• Creosote oil: preservative, paint
• Naphthalene: dye, pigment
• Tartaric acid: resin raw material, pigment

Other Information on Coal Tar

1. Stability and Reactivity of Coal Tar

Coal tar is stable under normal handling conditions, but will react with oxidizing substances. Contact with oxidizing substances should be avoided in storage.

Combustion of coal tar will produce black smoke, carbon monoxide, carbon dioxide, and other toxic substances. 

2. Coal Tar Safety

Coal Tar is a substance that has been shown to be harmful to the human body. Specifically, it is carcinogenic, toxic by oral ingestion, mildly irritating to the skin, may cause allergic skin reactions, may cause serious eye damage, may cause genetic disorders, may damage the nervous system, and may irritate the respiratory tract.

What Is Chondroitin Sulfate?

Sodium chondroitin sulfate is the sodium salt of chondroitin sulfate, an acidic mucopolysaccharide found in the cartilage of whales and sharks.

Chondroitin sulfate usually exists as a proteoglycan (a complex of sugar and protein with a special structure) and is widely distributed in connective tissues such as cartilage and skin, and in all tissues including the brain. Due to its water retention and viscosity, it also acts as a cushioning material in joints.

Its salt, chondroitin sulfate is a substance used as a medical drug and an over-the-counter drug.

Uses of Sodium Chondroitin Sulfate

Sodium Chondroitin Sulfate is a substance used in pharmaceuticals, foods, cosmetics, etc.

1. Pharmaceuticals

In pharmaceutical applications, it is a drug that is sold as both a prescription drug and an over-the-counter drug. As an ethical drug, it is indicated for the treatment of lumbago, arthralgia, and periarthritis of the shoulder in the form of an injectable solution, and for the protection of the superficial layer of the cornea in the form of eye drops.

As an over the counter drug, it is indicated for the treatment of arthralgia and neuralgia in oral form, and is also used as eye drops to protect the surface layer of the cornea in the same way as ethical drugs.

2. Food

In food applications, chondroitin sulfate is used as an emulsion stabilizer in the manufacturing process for mayonnaise, dressings, and other products. This is because chondroitin sulfate has excellent water absorption and water retention properties. It is also used in fish sausages to eliminate fish odor.

3.Cosmetics

In cosmetic applications, it is used as a moisturizer due to its smooth feel.

Properties of Chondroitin Sulfate

Chondroitin sulfate has a structure in which a sulfate is attached to a repeating disaccharide chain consisting of D-glucuronic acid (GlcA) and N-acetyl-D-galactosamine (GalNAc). Since there are variations in the position of the sulfate group and the presence or absence of GlcA epimerization in the repeating structure of this disaccharide unit, there are multiple isomers of chondroitin sulfate. Chondroitin sulfate sodium is a sulfate of each of these isomers.

Structure of Chondroitin Sulfate

In the monosaccharides that make up chondroitin sulfate sodium, the sulfate groups are mainly attached to the 4- and 6-positions of GalNAc. In chondroitin sulfate B (dermatan sulfate), GlcA of chondroitin sulfate is epimerized to form iduronic acid.

In chondroitin sulfate E, both positions 4 and 6 are sulfated, and in chondroitin sulfate D, the hydroxyl group of glucuronic acid is sulfated.

Types of Chondroitin Sulfate

The types of chondroitin sulfate sold include reagent products for research and development, chemical products, and pharmaceuticals.

1. Reagent Products for Research and Development

Reagent products for research and development include 0.1 g, 5 g, 25 g, and other capacities. In addition to those sold as chondroitin sulfate, isolated products of each of the aforementioned A~E types may also be sold.

In such cases, they are sold under product names such as Chondroitin Sulfate A Sodium, Chondroitin Sulfate B Sodium, Chondroitin Sulfate C Sodium, and Chondroitin Sulfate E Sodium, respectively. These reagent products are mainly used in the fields of cell biology and biochemistry, and are manufactured using chicken cartilage, porcine skin, squid cartilage, etc. as raw materials.

Note that products for research and development cannot be used for clinical purposes. 

2. Pharmaceutical Products

There are prescription drugs such as 200 mg injectable solution, 1%/3% eye drops, and various other over-the-counter drugs.

What Is Cholesterol?

Cholesterol is an organic compound with a steroidal structure. It is an essential component of cell membranes in animal cells. It is also a raw material for steroid hormones, sex hormones, and bile acids that promote fat absorption.

Since it is insoluble in blood, it must be transported in the form of particles called lipoproteins. Lipoproteins include LDL (low-density lipoprotein) and HDL (high-density lipoprotein), and the corresponding cholesterol is called LDL cholesterol and HDL cholesterol, respectively.

Uses of Cholesterol

The main uses of cholesterol are as a raw material for cosmetics, pharmaceuticals, and industrial products.

In cosmetics, cholesterol is used in creams and emulsions, and in pharmaceuticals, it is used in oral and topical formulations (e.g., anti-inflammatory ointments).

The esters of cholesterol and fatty acids have liquid crystalline properties. This is applied to industrial products in the form of liquid crystal materials called cholesteric liquid crystals. Cholesteric liquid crystals are used in electronic paper display technology and temperature sensors.

Properties of Cholesterol

Cholesterol is a white to pale yellow crystal with chemical formula C₂₇H₄₆O and a molecular weight of 386.65. It is lipophilic, nearly insoluble in water, and has a melting point of 149℃.

The coloring reaction can be seen in the Salkowski reaction and the Liebermann-Burchard reaction. In the Salkowski reaction, cholesterol is dissolved in chloroform and mixed with concentrated sulfuric acid. The chloroform layer turns red and the sulfuric acid layer turns yellow and fluoresces green.

In the Liebermann-Burchard reaction, cholesterol is dissolved in chloroform, a few drops of acetic anhydride are added, and then a few drops of concentrated sulfuric acid are added and mixed. The chloroform layer turns rose-colored and eventually turns green.

Structure of Cholesterol

Cholesterol has a steroidal skeleton consisting of three six-membered rings and one five-membered ring.

Cholesterol is a sterol because it has a hydroxyl group at position 3 of the steroid skeleton.

Other Information on Cholesterol

1. How It Is Synthesized in the Body

Cholesterol is mainly synthesized in the liver from the three major nutrients (carbohydrates, proteins, and fats). Acetyl coenzyme A is the first product of the breakdown of the three macronutrients.

Acetyl CoA is converted to mevalonic acid by the action of several enzymes. Mevalonic acid undergoes several chemical reactions to produce squalene, which has a steroidal skeleton. Squalene undergoes several more chemical reactions and is finally converted to cholesterol. 

2. Absorption in the Body

Cholesterol ingested from food is absorbed in the small intestinevia a protein called cholesterol transporter.

3. Action in the Body (LDL Cholesterol)

LDL cholesterol carries cholesterol to the cells and tissues of the body. When the amount of LDL cholesterol in the blood increases due to some abnormality, LDL cholesterol accumulates and oxidizes in the walls of blood vessels. The result is atherosclerosis.

LDL cholesterol is also called bad cholesterol because it promotes atherosclerosis. 

4. Action in the Body (HDL Cholesterol)

The function of HDL cholesterol is to collect unwanted cholesterol in cells and cholesterol deposited in blood vessel walls and return it to the liver.

HDL cholesterol is also called good cholesterol because it inhibits atherosclerosis. 

5. Criteria for Blood Cholesterol Levels

When the levels of LDL cholesterol and HDL cholesterol meet the following criteria, dyslipidemia is suspected.

• LDL Cholesterol: 140 mg/dl or higher
• HDL Cholesterol: less than 40 mg/dl