Penggunaan Istilah/Perkataan Yang Tidak Tepat dalam menjawab soalan kimia

Bil	Tidak Tepat	Sepatutnya
1	Mendakan perang	Enapan perang
2	Atom yang stabil	Atom mencapai susunan elektron oktet yang stabil
3	Konfigurasi elektron	Susunan elektron
4	Larutan jernih	Larutan tanpa warna
5	Ion iodida bertindak balas lengkap	Ion iodida habis bertindak balas//semua ion iodida bertindak balas lengkap
6	Tindak balas tidak berlaku(pemerhatian)	Tiada perubahan
7	Mempercepatkan kadar tindak balas	Kadar tindak balas bertambah/meningkat
8	Pembakaran dengan karbon	Pembakaran dengan oksigen
9	Magnesium lebih aktif daripada zink	Magnesium lebih reaktif daripada zink
10	SEK	Siri elektrokimia
11	Magnesium lebih reaktif daripada zink (siri elektrokimia)	Magnesium lebih elektropositif daripada zink.
12	Magnesium lebih elektropositif daripada zink.(siri kereaktifan)	Magnesium lebih reaktif daripada zink
13	Campurkan ammonia	Campurkan larutan ammonia
14	Larutan kalium permanganat	Larutan kalium manganat(VII) berasid
15	Polistirena dapat mencegah kehilangan haba	Polistirena mengurangkan kehilangan haba
16	Takat lebur ialah takat dimana pepejal berubah menjadi cecair	Takat lebur ialah suhu dimana pepejal berubah menjadi cecair
17	Bilangan elektron terluar	Bilangan elektron di petala luar/terluar
18	Fungsi titian garam ialah melengkapkan litar dan mengasingkan larutan	Fungsi titian garam ialah membenarkan ion melaluinya
19	Natrium menderma elektron	Atom natrium menderma satu elektron
20	Struktur elektron stabil	Susunan elektron octet
21	Elektron sudah penuh dipetala luar	Terdapat lapan elektron di petala luar
22	Tarikan nukleus ke atas petala luar	Tarikan nukleus ke atas elektron di petala luar
23	Saiz unsur bertambah	Saiz atom bertambah
24	Kadar tindak balas cepat	Kadar tindak balas tinggi/meningkat/bertambah
25	Kadar tindak balas perlahan	Kadar tindak balas rendah/berkurang
26	Saiz bahan yang kecil mempunyai luas permukaan yang besar	Saiz bahan yang kecil mempunyai jumlah luas permukaan yang besar
27	Bilangan zarah bertambah apabila kepekatan bertambah	Bilangan zarah per unit isipadu bertambah apabila kepekatan bertambah
28	Sebatian ion dapat mengalirkan arus elektrik	Sebatian ion dapat mengalirkan arus elektrik dalam keadaan lebur atau akueus.
29	Jisim atom relatif sesuatu unsur berapa kali satu atom unsur itu lebih berat daripada hidrogen	Jisim atom relatif sesuatu unsur berapa kali satu atom unsur itu lebih berat daripada satu atom hidrogen
30	Hidrokarbon ialah sebatian yang mengandungi karbon dan hidrogen.	Hidrokarbon ialah sebatian yang mengandungi karbon dan hidrogen sahaja.
31	Nombor pengoksidaan ferum berubah	Nombor pengoksidaan ferum bertambah dari +2 ke +3
32	Daya tarikan sebatian ion kuat	Daya tarikan antara ion dalam sebatian kuat
33	Daya tarikan dalam molekul lemah	Daya tarikan antara molekul lemah
34	Polimer adalah bahan yang terdiri daripada monomer-monomer	Polimer adalah bahan yang terbentuk daripada penggabungan monomer-monomer
35	Warna kalium mangganat(VII)menjadi tanpa warna	Warna ungu larutan kalium mangganat(VII)menjadi tanpa warna
36	Atom natrium dan klorin terletak dalam kala yang sama kerana kedua-dua atom mempunyai tiga petala	Atom natrium dan klorin terletak dalam kala yang sama kerana kedua-dua atom mempunyai tiga petala berisi elektron
37	Sabun terdiri daripada bahagian hidrofilik dan hidrofobik.	Molekul sabun terdiri daripada bahagian hidrofilik dan hidrofobik.
38	Sabun merendahkan tegangan permukaan pakaian	Sabun merendahkan tegangan permukaan air
39	Zink karbonat berwarna kuning semasa panas dan putih semasa sejuk	Zink oksida berwarna kuning semasa panas dan putih semasa sejuk
40	Kuprum didiscas dikatod	Ion kuprum didiscas dikatod

Index to Knee Injury, Pain, and Common Disorders

A) Cartilage Injuries and Disorders

1) Chondromalacia

Chondromalacia (pronounced KON-DRO-MAH-LAY-SHE-AH), also called chondromalacia patellae, refers to softening of the articular cartilage of the kneecap. The disorder occurs most often in young adults and may be caused by trauma, overuse, parts out of alignment, or muscle weakness. Instead of gliding smoothly across the lower end of the thigh bone, the kneecap rubs against it, thereby roughening the cartilage underneath the kneecap. The damage may range from a slight abnormality of the surface of the cartilage to a surface that has been worn away completely to the bone. Traumatic chondromalacia occurs when a blow to the knee cap tears off either a small piece of articular cartilage or a large fragment containing a piece of bone (osteochondral fracture).

What Are the Symptoms of Chondromalacia? How Is It Diagnosed?

The most frequent symptom of chondromalacia is a dull pain around or under the kneecap that worsens when walking down stairs or hills. A client may also feel pain when climbing stairs or during other activities when the knee bears weight as it is straightened. The disorder is common in runners and is also seen in skiers, cyclists, and soccer players. A client's description of symptoms and a follow-up x-ray usually help the doctor make a diagnosis. Although arthroscopy can confirm the diagnosis of chondromalacia, it is not performed unless the condition requires extensive treatment.

How Is Chondromalacia Treated?

Many doctors recommend that clients with chondromalacia perform low-impact exercises that strengthen muscles, particularly the inner part of the quadriceps, without injuring joints. Swimming, riding a stationary bicycle, and using a cross-country ski machine are acceptable as long as the knee is not bent more than 90 degrees. Electrical stimulation may also be used to strengthen the muscles.

If these treatments fail to improve the condition, the physician may perform arthroscopic surgery to smooth the surface of the articular cartilage and "wash out" cartilage fragments that cause the joint to catch during bending and straightening. In more severe cases of chondromalacia, surgery may be necessary to correct the angle of the kneecap and relieve friction involving the cartilage or to reposition parts that are out of alignment.

2) Injuries to the Meniscus

The two menisci are easily injured by the force of rotating the knee while bearing weight. A partial or total tear of a meniscus may occur when a client quickly twists or rotates the upper leg while the foot stays still (for example, when dribbling a basketball around an opponent or turning to hit a tennis ball). If the tear is tiny, the meniscus stays connected to the front and back of the knee; if the tear is large, the meniscus may be left hanging by a thread of cartilage. The seriousness of a tear depends on its location and extent.

What Are the Symptoms of Injury?

Generally, when people injure a meniscus, they feel some pain, particularly when the knee is straightened. The pain may be mild, and the client may continue activity. Severe pain may occur if a fragment of the meniscus catches between the femur and tibia. Swelling may occur soon after injury if blood vessels are disrupted, or swelling may occur several hours later if the joint fills with fluid produced by the joint lining (synovium) as a result of inflammation.

If the synovium is injured, it may become inflamed and produce fluid to protect itself. This causes swelling of the knee. Sometimes, an injury that occurred in the past but was not treated becomes painful months or years later, particularly if the knee is injured a second time. After any injury the knee may click, lock, or feel weak. Symptoms of menisci injury may disappear on their own but frequently, symptoms persist or return and require treatment.

How Is Meniscal Injury Diagnosed?

In addition to listening to the client's description of the onset of pain and swelling, the physician may perform a physical examination and take x-rays of the knee. The examination may include a test in which the doctor flexes (bends) the leg then rotates the leg outward and inward while extending it. Pain or an audible click suggests a meniscal tear. An MRI test may be recommended to confirm the diagnosis. Occasionally, the doctor may use arthroscopy to help diagnose and treat a meniscal tear.

How Is an Injured Meniscus Treated?

If the tear is minor and the pain and other symptoms go away, the doctor may recommend a muscle-strengthening program. Exercises for meniscal problems are best performed with initial guidance from a doctor and physical therapist or exercise therapist. The therapist will make sure that the client does the exercises properly and without risk of new or repeat injury.

The following exercises after injury to the meniscus are designed to build up the quadriceps and hamstring muscles and increase flexibility and strength.

• Warming up the joint by riding a stationary bicycle, then straightening and raising the leg (but avoiding straightening the leg too much).
• Extending the leg while sitting (a weight may be worn on the ankle for this exercise).
• Raising the leg while lying on the stomach.
• Exercising in a pool, including walking as fast as possible in chest-deep water, performing small flutter kicks while holding onto the side of the pool, and raising each leg to 90 degrees in chest-deep water while pressing the back against the side of the pool.

If the tear to a meniscus is more extensive, the doctor may perform either arthroscopic surgery or "open surgery" to see the extent of injury and to repair the tear. The doctor can suture (sew) the meniscus back in place if the client is relatively young, the injury is in an area with a good blood supply, and the ligaments are intact. Most young athletes are able to return to vigorous sports with meniscus-preserving repair.

If the client is elderly or the tear is in an area with a poor blood supply, the doctor may cut off a small portion of the meniscus to even the surface. In some cases, the doctor removes the entire meniscus. However, degenerative changes, such as osteoarthritis, are more likely to develop in the knee if the meniscus is removed.

Medical researchers are currently investigating a procedure called an allograft, in which the surgeon replaces the meniscus with one from a cadaver. A grafted meniscus is fragile and may shrink and tear easily. Researchers have also attempted to replace a meniscus with an artificial one, but the procedure is even less successful than an allograft.

Recovery after surgery to repair a meniscus takes several weeks longer and post-operative activity is slightly more restricted than when the meniscus is removed. Nevertheless, putting weight on the joint actually fosters recovery. Regardless of the form of surgery, rehabilitation usually includes walking, bending the legs, and doing exercises that stretch and build up the leg muscles. The best results of treatment for meniscal injury are obtained in people who do not show articular cartilage changes and who have an intact anterior cruciate ligament.

3) Arthritis of the Knee

Arthritis of the knee is most often osteoarthritis, a degenerative disease where cartilage in the joint gradually wears away. In rheumatoid arthritis, which can also affect the knees, the joint becomes inflamed and cartilage may be destroyed. Arthritis not only affects joints, it may also affect supporting structures such as muscles, tendons, and ligaments.

Osteoarthritis may be caused by excess stress on the joint, such as from repeated injury, deformity, or if a client is overweight. It most often affects middle-aged and older people. A young client who develops osteoarthritis may have an inherited form of the disease or may have experienced continuous irritation from an un-repaired torn meniscus or other injury. Rheumatoid arthritis usually affects people at an earlier age than osteoarthritis.

What Are the Signs of Knee Arthritis and How Is It Diagnosed?

A client who has arthritis of the knee may experience pain, swelling, and a decrease in knee motion. A common symptom is morning stiffness that lessens after moving around. Sometimes the knee joint locks or clicks when the knee is bent and straightened, but these signs may also occur in other knee disorders. The doctor may confirm the diagnosis by performing a physical examination and taking x-rays, which typically show a loss of joint space.

Blood tests may be helpful for diagnosing rheumatoid arthritis, but other tests may be needed as well. Analysis of fluid from the knee joint may be helpful in diagnosing some kinds of arthritis. The doctor may use arthroscopy to directly visualize damage to cartilage, tendons, and ligaments and to confirm a diagnosis, but arthroscopy is usually done only if a repair procedure is to be performed.

How Is Arthritis of the Knee Treated?

Most often osteoarthritis of the knee is treated with analgesics (pain-reducing medicines), such as aspirin or acetaminophen (Tylenol):* non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Motrin, Nuprin, Advil); and exercises to restore joint movement and strengthen the knee. Losing excess weight can also help people with osteoarthritis.

Rheumatoid arthritis of the knee may require a treatment plan that includes physical therapy and use of more powerful medications. In people with arthritis of the knee, a seriously damaged joint may need to be surgically replaced with an artificial one. (Note: A new procedure designed to stimulate the growth of cartilage using a client's own cartilage cells is being used experimentally to repair cartilage injuries at the end of the femur at the knee. It is not a treatment for arthritis.)

B) Ligament Injuries

1) Anterior Cruciate (ACL) Ligament Injury

Ligaments are strong, elastic bands of tissue that connect bone to bone. They provide strength and stability to the joint. The ACL is one of four ligaments connect the femur and tibia:

The anterior cruciate ligament (ACL), in the center of the knee, limits rotation and the forward movement of the tibia.

What Are the Causes of Injury to the Cruciate Ligaments?

Injury to the cruciate ligaments of the knee is sometimes referred to as a "sprain." The anterior cruciate ligament is most often stretched, torn, or both by a sudden twisting motion (for example, when the feet are planted one way and the knees are turned another way). The posterior cruciate ligament is most often injured by a direct impact, such as in an automobile accident or football tackle.

What Are the Symptoms of Cruciate Ligament Injury? How Is Injury Diagnosed?

Injury to a cruciate ligament may not cause pain. Rather, the client may hear a popping sound, and the leg may buckle when he or she tries to stand on it. To diagnose an injury, the doctor may perform several tests to see if the parts of the knee stay in proper position when pressure is applied in different directions. A thorough examination is essential to the diagnosis. An MRI is very accurate in detecting a complete tear, but arthroscopy may be the only reliable means of detecting a partial tear.

How Are Cruciate Ligament Tears Treated?

For an incomplete tear, the doctor may recommend that the client begin an exercise program to strengthen surrounding muscles. The doctor may also prescribe a protective knee brace for the client to wear during activity. For a completely torn anterior cruciate ligament in an active athlete and motivated client, the doctor is likely to recommend surgery. The surgeon may reattach the torn ends of the ligament or reconstruct the torn ligament by using a piece (graft) of healthy ligament from the client (autograft) or from a cadaver (allograft).

Although repair using synthetic ligaments has been tried experimentally, the procedure has not yielded as good results as use of human tissue. One of the most important elements in a client's successful recovery after cruciate ligament surgery is following an exercise and rehabilitation program for 4 to 6 months that may involve the use of special exercise equipment at a rehabilitation or sports center. Successful surgery and rehabilitation will allow the client to return to a normal full lifestyle.

2) Posterior Cruciate (PCL) Ligament Injury

Ligaments are strong, elastic bands of tissue that connect bone to bone. They provide strength and stability to the joint. The PCL is one of four ligaments connect the femur and tibia:

The posterior cruciate ligament (PCL), also in the center of the knee, limits backward movement of the tibia.

What Are the Causes of Injury to the Cruciate Ligaments?

Injury to the cruciate ligaments of the knee is sometimes referred to as a "sprain." The anterior cruciate ligament is most often stretched, torn, or both by a sudden twisting motion (for example, when the feet are planted one way and the knees are turned another way). The posterior cruciate ligament is most often injured by a direct impact, such as in an automobile accident or football tackle.

What Are the Symptoms of Cruciate Ligament Injury? How Is Injury Diagnosed?

Injury to a cruciate ligament may not cause pain. Rather, the client may hear a popping sound, and the leg may buckle when he or she tries to stand on it. To diagnose an injury, the doctor may perform several tests to see if the parts of the knee stay in proper position when pressure is applied in different directions. A thorough examination is essential to the diagnosis. An MRI is very accurate in detecting a complete tear, but arthroscopy may be the only reliable means of detecting a partial tear.

How Are Cruciate Ligament Tears Treated?

For an incomplete tear, the doctor may recommend that the client begin an exercise program to strengthen surrounding muscles. The doctor may also prescribe a protective knee brace for the client to wear during activity. For a completely torn anterior cruciate ligament in an active athlete and motivated client, the doctor is likely to recommend surgery. The surgeon may reattach the torn ends of the ligament or reconstruct the torn ligament by using a piece (graft) of healthy ligament from the client (autograft) or from a cadaver (allograft).

Although repair using synthetic ligaments has been tried experimentally, the procedure has not yielded as good results as use of human tissue. One of the most important elements in a client's successful recovery after cruciate ligament surgery is following an exercise and rehabilitation program for 4 to 6 months that may involve the use of special exercise equipment at a rehabilitation or sports center. Successful surgery and rehabilitation will allow the client to return to a normal full lifestyle.

2) Medial Collateral (MCL) Ligament Injury

Ligaments are strong, elastic bands of tissue that connect bone to bone. They provide strength and stability to the joint. The MCL is one of four ligaments connect the femur and tibia:

The medial collateral ligament (MCL) provides stability to the inner (medial) aspect of the knee.

What Is the Most Common Cause of Injury to the Medial Collateral Ligament?

The medial collateral ligament is more easily injured than the lateral collateral ligament. It is most often caused by a blow to the outer side of the knee, which often happens in contact sports like football or hockey, which stretches and tears the ligament on the inner side of the knee.

What Are the Symptoms of Collateral Ligament Injury? How Is Injury Diagnosed?

When injury to the medial collateral ligament occurs, a client may feel a pop and the knee may buckle sideways. Pain and swelling are common. A thorough examination is essential to determine the nature and extent of injury. To diagnose a collateral ligament injury, the doctor exerts pressure on the side of the knee to determine the degree of pain and looseness of the joint. An MRI is helpful in diagnosing injuries to these ligaments.

How Are Collateral Ligament Injuries Treated?     

Most sprains of the collateral ligaments will heal if the client follows a prescribed exercise program. In addition to exercise, the doctor may recommend that the client apply ice packs to reduce pain and swelling and wear a small sleeve-type brace to protect and stabilize the knee. A sprain may take 2 to 4 weeks to heal. A severely sprained or torn collateral ligament may be accompanied by a torn anterior cruciate ligament, which usually requires surgical repair.

4) Lateral Collateral (LCL) Ligament Injury

Ligaments are strong, elastic bands of tissue that connect bone to bone. They provide strength and stability to the joint. The LCL is one of four ligaments connect the femur and tibia:

The lateral collateral ligament (LCL) provides stability to the outer (lateral) aspect of the knee.

What Is the Most Common Cause of Injury to the Lateral Collateral Ligament?

The LCL is usually injured by pressure placed on the knee-joint from the inside, resulting in stress on the outside of the joint (varus stress).

What Are the Symptoms of Collateral Ligament Injury? How Is Injury Diagnosed?

When injury to the medial collateral ligament occurs, a client may feel a pop and the knee may buckle sideways. Pain and swelling are common. A thorough examination is essential to determine the nature and extent of injury. To diagnose a collateral ligament injury, the doctor exerts pressure on the side of the knee to determine the degree of pain and looseness of the joint. An MRI is helpful in diagnosing injuries to these ligaments.

C) Tendon Injuries and Disorders

1) Tendonitis and Ruptured Tendons

Knee tendon injuries range from tendonitis (inflammation of a tendon) to a ruptured (torn) tendon. If a client overuses a tendon during certain activities such as dancing, cycling, or running, the tendon stretches like a worn-out rubber band and becomes inflamed. Movements such as trying to break a fall may cause excessive contraction of the quadriceps muscles and tear the quadriceps tendon above the patella or the patellar tendon below the patella. This type of injury is most likely to happen in older people whose tendons tend to be weaker.

Tendonitis of the patellar tendon is sometimes called jumper's knee. This is because in sports requiring jumping, such as basketball, the muscle contraction and force of hitting the ground after a jump strain the tendon. The tendon may become inflamed or tear after repeated stress.

What Are the Symptoms of Tendon Injuries? How Are Injuries Diagnosed?

People with tendonitis often have tenderness at the point where the patellar tendon meets the bone. They also may feel pain during faster movements, such as running, hurried walking, or jumping. A complete rupture of the quadriceps or patellar tendon is not only painful but also makes it difficult for a client to bend, extend, or lift the leg against gravity. If there is not much swelling, the doctor will be able to feel a defect in the tendon near the tear during a physical examination. An x-ray will show that the patella is lower in position than normal in a quadriceps tendon tear and higher than normal in a patellar tendon tear. The doctor may use an MRI to confirm a partial or total tear.

How Are Knee Tendon Injuries Treated?

Initially, the doctor may ask a client with tendonitis to rest, elevate, and apply ice to the knee and to take medicines such as aspirin or ibuprofen to relieve pain and decrease inflammation and swelling. If the quadriceps or patellar tendon is completely ruptured, a surgeon will reattach the ends. After surgery, the client will wear a cast for 3 to 6 weeks and use crutches. If the tear is only partial, the doctor might apply a cast without performing surgery.

A partial or complete tear of a tendon requires an exercise program as part of rehabilitation that is similar to but less vigorous than that prescribed for ligament injuries. The goals of exercise are to restore the ability to bend and straighten the knee and to strengthen the leg to prevent a repeat knee injury. A rehabilitation program may last 6 months, although the client can return to many activities before then.

2) Osgood-Schlatter Disease

Osgood-Schlatter disease is caused by repetitive stress or tension on a part of the growth area of the upper tibia (the apophysis). It is characterized by inflammation of the patellar tendon and surrounding soft tissues at the point where the tendon attaches to the tibia. The disease may also be associated with an avulsion injury, in which the tendon is stretched so much that it tears away from the tibia and takes a fragment of bone with it. The disease most commonly affects active young people, particularly boys between the ages of 10 and 15, who play games or sports that include frequent running and jumping.

What Are the Symptoms of Osgood-Schlatter Disease? How Is It Diagnosed?

People with this disease experience pain just below the knee joint that usually worsens with activity and is relieved by rest. A bony bump that is particularly painful when pressed may appear on the upper edge of the tibia (below the knee cap). Usually, motion of the knee is not affected. Pain may last a few months and may recur until a child's growth is completed.

Osgood Schlatter disease is most often diagnosed by the symptoms. An x-ray may be normal, or show an avulsion injury, or, more typically, show that the apophysis is in fragments.

How Is Osgood-Schlatter Disease Treated?

Usually, the disease disappears without treatment. Applying ice to the knee when pain first begins helps relieve inflammation and is sometimes used along with stretching and strengthening exercises. The doctor may advise the client to limit participation in vigorous sports. Children who wish to continue participating in moderate or less stressful sports may need to wear knee pads for protection and apply ice to the knee after activity. If a great deal of pain is felt during sports activities, participation may be limited until any remaining discomfort is tolerable.

3) Iliotibial Band Syndrome

This is an overuse inflammatory condition due to friction (rubbing) of a band of a tendon over the outer bone (lateral condyle) of the knee. Although iliotibial band syndrome may be caused by direct injury to the knee, it is most often caused by the stress of long-term overuse, such as sometimes occurs in sports training.

What Are the Symptoms of Iliotibial Band Syndrome and How Is It Diagnosed?

A client with this syndrome feels an ache or burning sensation at the side of the knee during activity. Pain may be localized at the side of the knee or radiate up the side of the thigh. A client may also feel a snap when the knee is bent and then straightened. Swelling is usually absent and knee motion is normal. The diagnosis of this disorder is usually based on the client's symptoms, such as pain at the lateral condyle, and exclusion of other conditions with similar symptoms.

How Is Iliotibial Band Syndrome Treated?

Usually, iliotibial band syndrome disappears if the client reduces activity and performs stretching exercises followed by muscle-strengthening exercises. In rare cases when the syndrome doesn't disappear, surgery may be necessary to split the tendon so it is not stretched too tightly over the bone.

D) Other Knee Injuries

1) Osteochondritis Dissecans

Osteochondritis dissecans results from a loss of the blood supply to an area of bone underneath a joint surface and usually involves the knee. The affected bone and its covering of cartilage gradually loosen and cause pain. A client with this disruption of the joint may eventually develop osteoarthritis. This disorder usually arises spontaneously in an active adolescent or a young adult. It may be due to a slight blockage of a small artery or to an unrecognized injury or tiny fracture that damages the overlying cartilage.

The bone undergoes avascular necrosis (degeneration from lack of a blood supply). The involvement of several joints or the appearance of osteochondritis dissecans in several family members may indicate that the disorder is inherited.

What Are the Symptoms of Osteochondritis Dissecans? How Is It Diagnosed?

If spontaneous healing doesn't occur, cartilage eventually separates from the diseased bone and a fragment breaks loose into the knee joint, causing locking of the joint, weakness, and sharp pain. An x-ray, MRI, or arthroscopy can determine the condition of the cartilage and be used to diagnose osteochondritis dissecans.

How Is Osteochondritis Dissecans Treated?

If cartilage fragments have not broken loose, a surgeon may fix them in place with pins or screws that are sunk into the cartilage to stimulate a new blood supply. If fragments are loose, the surgeon may scrape down the cavity to reach fresh bone and add a bone graft and fix the fragments in position. Fragments that cannot be mended are removed, and the cavity is drilled or scraped to stimulate new growth of cartilage. Research is currently being done to assess the use of cartilage cell transplants and other tissues to treat this disorder.

2) Plica Syndrome

Plica (pronounced PLI-KAH) syndrome occurs when plicae (bands of remnant synovial tissue) are irritated by overuse or injury. Synovial plicae are remnants of tissue pouches found in the early stages of fetal development. As the fetus develops, these pouches normally combine to form one large synovial cavity. If this process is incomplete, plicae remain as four folds or bands of synovial tissue within the knee. Injury, chronic overuse, or inflammatory conditions are associated with development of this syndrome.

What Are the Symptoms of Plica Syndrome? How Is It Diagnosed?

People with this syndrome are likely to experience pain and swelling, a clicking sensation, and locking and weakness of the knee. Because the symptoms are similar to symptoms of some other knee problems, plica syndrome is often misdiagnosed. Diagnosis usually depends on the exclusion of other conditions that cause similar symptoms.

How Is Plica Syndrome Treated?

The goal of treatment is to reduce inflammation of the synovium and thickening of the plicae. The doctor usually prescribes medicine such as ibuprofen to reduce inflammation. The client is also advised to reduce activity, apply ice and compression wraps (elastic bandage) to the knee, and do strengthening exercises. If this treatment program fails to relieve symptoms within 3 months, the doctor may recommend arthroscopic or open surgery to remove the plicae. A cortisone injection into the region of the plica folds helps about half of the clients treated. The doctor can also use arthroscopy to confirm the diagnosis and treat the problem.

Moral dan Motivasi Pelajar

7 Langkah Mencapai Matlamat

"Orang yang berjaya dalam hidup adalah orang yang nampak tujuannya dengan jelas dan menjurus kepadanya tanpa menyimpang." - Cecil B. DeMille

Artikel motivasi ini menjelaskan langkah-langkah, cara-cara, kaedah-kaedah, strategi-strategi, teknik-teknik, tip-tip, panduan-panduan atau rahsia-rahsia mencapai matlamat dan kejayaan yang anda inginkan.
Untuk mencapai matlamat anda dan berjaya dalam kehidupan, anda mestilah membina suatu kebiasaan berdasarkan langkah-langkah yang telah terbukti keberkesanannya seperti berikut:

1. Wujudkan Keinginan Anda Sebesar Mungkin
Keinginan tersebut mestilah yang benar-benar anda idamkan. Bagaimana menyemarakkan keinginan anda? Duduk dan tulis semua keinginan anda. Nyatakan faedah-faedah dan kebaikan-kebaikan mencapai segala keinginan anda itu. Fikir dan tulislah sepuas-puasnya. Apabila senarai anda menjangkau 50 hingga 100, suatu bentuk perasaan atau semangat pada diri anda akan timbul. Teruskan. Anda akan mula menjadi lebih bersemangat. Jika anda terus menulis dan menghayati segala matlamat anda itu, semangat anda akan bertambah menyala, berapi-api! InsyaAllah.

2. Tuliskan Matlamat-Matlamat Anda
TULIS matlamat-matlamat anda di atas sehelai kertas. Jika anda tidak tulis, ia hanya akan menjadi angan-angan sahaja. Salinkannya ke dalam Buku Matlamat anda. Ini PENTING, kerana dengan berbuat demikian, ia akan menjadi perkara yang penting bagi anda. Dengan berbuat demikian juga, ia akan mula meresap ke dalam minda separa sedar anda.

3. Tetapkan Tempoh dan Bila Anda Akan Mencapai Matlamat Anda
Kaji tahap atau kedudukan anda sekarang berbanding dengan apa yang anda inginkan. Kira dan tentukan berapa banyak masa yang anda perlukan untuk mencapai matlamat anda itu. TETAPKAN bila matlamat tersebut mesti anda capai.

4. Buat Perancangan
RANCANGKAN tindakan-tindakan anda. Senaraikan semua aktiviti mengikut susunan keutamaannya. Perbaiki senarai anda; optimumkannya, sempurnakannya.

5. Gambarkan Kejayaan Pada Minda Anda
Letakkan suatu Studio Filem di minda anda! Bayangkan satu GAMBARAN MENTAL yang anda telah berjaya mencapainya. Buat imej minda yang jelas dan terang pada mata minda anda. Mainkan gambaran itu berulang-ulang – berkali-kali di fikiran anda. Ingatlah bahawa: "Orang yang berjaya dalam hidup adalah orang yang nampak tujuannya dengan jelas dan menjurus kepadanya tanpa menyimpang." - Cecil B. DeMille. Ingatlah juga kata Mahatma Gandhi: Seseorang itu

6. Tangani Halangan
1) Kenalpastikan halangan-halangan yang perlu anda atasi.
2) Tumpukan kepada usaha mendapat bantuan; bantuan yang anda akan perlukan untuk mencapai matlamat anda - misalnya pengetahuan, pakar-pakar, penasihat-penasihat atau badan-badan tertentu. adalah hasil dari fikirannya. Apa yang dia fikir, itulah yang dia akan menjadi".

7. Baki 90% Adalah Usaha dan Keazaman Anda
Sokong rancangan anda dengan KEAZAMAN (Resolve) dan SEMANGAT TIDAK MENGENAL PUTUS ASA (Persistence). Tekadkan semangat. Tumpukan kepada kejayaan. Fokuskan segala perhatian dan tenaga anda untuk mencapai segala matlamat anda pada waktu yang anda sendiri tetapkan. Bulatkan hati dan fikiran. Jangan sekali-kali berputus asa terhadap sebarang cabaran. Lakukanlah tindakan-tindakan proaktif dan produktif.

Insya-Allah, dengan diiringi doa, keazaman, disiplin yang tinggi serta usaha gigih, anda akan mencapai apa juga matlamat yang anda ingini dan impikan.

petikan dari Taidin Suhaimi

Why do rainbows appear? What are the differences between primary rainbow and secondary rainbow?

White sunlight actually contains a wide variety of colors, which may be roughly classified as seven colors, namely, red, orange, yellow, green, blue, indigo and violet. Normally, we see the sun in white color. After rain, there are still some tiny water droplets remained in the air. If there is sunshine a white sunbeam will be reflected and refracted by these tiny droplets. Different colors of light have different refractivity. They will be reflected in slightly different directions inside a water droplet. If we observe the sky from different angles of elevation, we will see different water droplets reflecting out different colors of light. A rainbow is formed (Fig. 1).

Both the primary and secondary rainbows are phenomena that formed by the reflection and refraction of sunlight in tiny water droplets. When a sunbeam is being refracted twice and reflected once by the droplet, a primary rainbow will form (Fig. 2 a). If the beam is being refracted twice and reflected twice, a secondary rainbow will form (Fig. 2 b). As the secondary rainbow is formed by one more reflection than the primary rainbow, it is much fainter and rare to see. On the other hand, since the paths of sunbeams in a primary rainbow and a secondary rainbow are different, the colors of the secondary rainbow are arranged in just the reverse order of the primary one (compare Fig. 2 a and 2 b).

What is a mirage? How is it formed?

Fig. 1  In regions of air with temperature decreases with altitude, light will travel in a curved path due to refraction.

Fig. 2  Refraction occurs when a light beam travels from glass to the air. The angle of incidence i is smaller than the angle of refraction r.

Fig. 3  Total internal reflection occurs when the incident angle i is larger than the critical angle c.

Fig. 4   The path of light when a mirage happens.

A traveler has lost his way in the desert. Enduring thirst and hunger, he suddenly saw an oasis, so the overjoyed man quickly ran towards it. To his great disappointment, it was just an illusion produced by a mirage. Such an episode was often pictured in movies, yet the optical magic that the nature plays with us - mirage - really exists in reality. Its formation is a result of the refraction and the total internal reflection of light in the air. 

To investigate the formation of a mirage, we firstly need to understand why light is refracted in the air. Regions of air at different temperatures have different refractive indexes, just like many different mediums. The closer the air is to the ground, the hotter it will be, and its refractive index will be smaller. We could imagine the air as many layers of medium with a particular refractive index for every layer, and the refractive index is smaller for those that are closer to the ground. Thus when light travels in air, its path is as shown in Fig.1. 

On the other hand, we should also understand what total internal reflection is. If light travels from glass to the air with a small incident angle, part of the light will be reflected back while the remaining part will be refracted, passing out from the glass. As the refractive index of glass is larger than that of the air, the refracted angle is always larger than the incident angle (Fig. 2). When the incident angle becomes larger, the refracted light will get closer and closer to the interface between the air and the glass. When it is larger than the critical angle, the light will only be reflected but not refracted. This phenomenon is called total internal reflection (Fig. 3). 

Fig. 4 shows the path of light when a mirage happens. Suppose there is an oasis and the light it emits at point A is refracted by the air, the light will travel through a curved path. Total internal reflection occurs at point B and will cause the light to travel upwards. Then the light is refracted by the air again. At last, it will enter the eyes of the observer at point C, producing an illusion that the oasis is close to him. 

Total internal reflection has been discovered for a long time already. Some of its broad applications include optical fibre, single lens reflex camera and binocular telescope.

Why do sound waves transmit farther at night? Is it because it is quieter at night?

If you go to the beach on vacation, during the night, you will discover that voice of people far away can be heard clearly. You may wonder, it is because it is quieter at night than in the daytime. Therefore it is easy to hear the sound far away. However, it is only one of the reasons. Actually, sound transmits farther at night may be related to refraction of sound waves! First, sound is the vibration of air, and it is a kind of wave motion. The propagation of sound wave is faster in hot air and slower in cold air. Therefore regions of air at different temperatures have different refractive indices, just like media with different optical densities. When sound wave propagates in air whose temperature changes with altitude, refraction of air happens. Sound will move towards areas with lower temperatures. In the daytime, when the sun shines the earth, the air near the earth surface is hotter than the air above. Sound waves will be refracted to the sky (Fig. 1). On the contrary, in the nighttime, the air near the surface is cooler and sound waves are refracted to the earth surface (Fig. 2).