Bone screws, also known as fracture fixation screws, are commonly used in clinical practice to fix orthopedic implants.
Bone screws are usually used to fix internal fractures or dislocations by directly screing into two different bone blocks or fixing an internal implant such as a bone plate to achieve fracture fixation, position the bone and promote its healing. Bone screws are used in a wide range of areas, including the shoulder, elbow, hip, knee, spine, etc. For example, pedicle screw systems are used for spinal fusion, and compression bone screws are commonly used for foot and ankle surgery or fixation of other fractures under pressure. Similar to traditional mechanical screws, the main structures of bone screws also include nail cap, nail body, and nail tip. Screws can be used to fix bone plates or bone fragments. When used for the former, they are called plate screws, and when used for the latter (to prevent the collapse of bone fragments), they are called positional screws. The latter can be inserted into the plate holes, and can be placed on the bone alone (also known as compression screws). Compression screws can be used to increase interfragment pressure.
(1) The screw cap
The screw cap has three main functions: the first is to optimize the force. The protruding cap makes the contact area between the screw and bone larger, increases the load area, optimizes the local force at the screw insertion site, and reduces the risk of bone rupture caused by excessive stress. The second is the positioning effect. The prominent cap makes the bone nail can only be screwed into a certain depth to prevent the whole bone nail from being screwed into the bone completely. The third function is to provide the position of force application by rotating the force groove at the cap to move the bone nail forward and drive it into the bone. Now, the force groove is mostly inner hexagonal, which does not require axial force to maintain the actuator in the center position and is suitable for a wider range of fractures.
(2) Screw the body
The size of the nail body determines the strength and fatigue resistance of the bone nail. The larger the diameter of the nail body, the stronger the strength will be, and the corresponding fatigue resistance will be better. In addition to the diameter of the nail body, the pitch and tooth depth of the screw body thread are also the key parameters of the nail body design. Different thread design has an important effect on the pressure and occlusal performance of the screw.
(3) Screw tip
Tapping is the process of phalangeal nail cutting thread in the bone. According to the shape of the nail tip, the bone nail can be divided into self-tapping nail and non-self-tapping nail. The nail tip of the self-tapping nail is sharper and can be directly screwed into the bone without pre-drilling. Usually, self-tapping screws are used for Cancellous bone, and the bone is compressed when the screw is inserted, so as to increase the bone density of the occlusal part locally and enhance the occlusal effect. However, when inserting screws in Cortical bone, the screw channel is generally pre-punched, and then the bone screw is screwed. Usually, the self-tapping screw is not directly used to prevent the bone screw from being stuck or damaged because the cortical bone is too hard.
Bone Screw,Cancellous Screw,screws in bone,Cortical Screw Jiangsu Aomed Ortho Medical Technology Co.,Ltd , https://www.aomedortho.com
Spice processing technology
Spiced oyster sauce is a nutritious and flavorful condiment that has gained widespread popularity among consumers due to its convenience, hygiene, and unique taste. It is not only rich in essential nutrients but also offers a distinct culinary experience, making it a preferred choice for many households and food businesses.
The main ingredients used in the preparation of spiced wolfberry (a type of preserved delicacy) include 5 kg of soy sauce, 13.5 kg of salt (with 12.5 kg used for salting and 1 kg for boiling), 1 kg of sugar, 500 grams of rice wine, 200 grams of monosodium glutamate, 5 grams of sodium nitrite, and a variety of spices such as 30 grams of star anise, 25 grams of pepper, 16 grams of fennel, 15 grams of cinnamon, 10 grams of cloves, 100 grams of onion, and 60 grams of ginger. These spices are typically wrapped in gauze to prevent them from mixing directly with the product during cooking.
The processing procedure involves several detailed steps:
1. First, healthy crickets are slaughtered, cleaned thoroughly by removing their hair, mouth, toes, wing tips, and anus. The internal organs are then removed and the body is washed repeatedly under running water to ensure cleanliness.
2. After drying the cleaned crickets, they are lightly salted to enhance firmness. The amount of salt used is about 2.5% of the total weight of the crickets. The marinating time varies depending on the season—longer in winter and shorter in summer. Typically, it takes around 1 to 2 hours at room temperature. After marinating, the crickets are rinsed again to remove excess salt.
3. The next step involves shaping the crickets by flattening them and crossing their legs so that the ankle joints are inserted into the anus, giving them a neat and compact form.
4. The shaped crickets are then fried in oil heated to 180°C–210°C for 2–3 minutes until golden brown. They are quickly removed and placed in a basket to drain excess oil and cool down.
5. In the braising stage, all the prepared ingredients are added to a pot along with old broth. Water is added equal to the weight of the crickets, and the fried crickets are then placed inside. The mixture is cooked at 90°C–95°C for approximately one hour to allow the flavors to fully develop.
6. Once cooked, the crickets are carefully removed from the pot and cooled in a refrigerated room maintained at 4°C–7°C to preserve their texture and quality.
7. The cooled product is then weighed accurately in a clean packaging area and placed into vacuum-seal bags using a vacuum packing machine to ensure freshness and extend shelf life.
8. The sealed packages are sterilized in an autoclave at 121°C under a pressure range of 12.7 MPa–14.5 MPa for 5–10 minutes to eliminate any harmful microorganisms.
9. After sterilization, the packages are taken out, dried, and inspected for any defects such as air pockets or broken seals. A sample from each batch is tested for both physicochemical and microbiological properties to ensure safety and quality.
10. Finally, the qualified products are packed into colored bags and placed into boxes for storage or sale. The storage environment should be kept at a stable temperature, ideally around 0°C, to maintain product integrity and freshness.
This detailed process ensures that the final product is not only delicious but also safe and of high quality, meeting the expectations of modern consumers.