Coronary Heart Disease

Figure 1 - The artery on the right is a normal healthy artery.
The artery on the left is suffering from CHD since
it's walls are narrowing because of the fatty deposits.

Figure 2 - This diagram shows the dangers of atherosclerosis. The artery in
the middle right, has been developing atherosclerosis and has been filling up
with plaque reducing blood flow. The bottom artery is blocked which
could lead to heart attacks and strokes due to no oxygen through the blood.

Different types of fat can have many different outcomes on human health. However, the main concern and the most harmful issue is the coronary heart disease (CHD).  When CHD occurs the coronary arteries in our circulatory system, are blocked by fats, which lead to harmful outcomes such as blood clotting and heart attacks. Our hearts and all other muscles in our bodies need oxygen to function. Due to diseases such as CHD, the oxygen rich blood is unable to reach our hearts (and other muscles) because the arteries have developed a blockage. These fatty deposits are also known as plaque which cause the blockage. Plaque is made out of cholesterol and other fatty substances.

Due to the buildup of plaque, over the course of several years, one is able to develop a condition called Atherosclerosis, which in fact is the hardening of the arteries, where the plaque builds up inside the arteries’ walls. The plaque is able to harden and even break off over time. The hardened plaque narrows the arteries which results in the decrease of oxygen rich blood flow to the heart. If the plaque breaks off or ruptures it is able to create a blood clot which could for the most part block blood or completely block blood flow through the coronary arteries. This leads to heart attacks and strokes. If heart attacks and strokes are not treated quick, the consequences can be fatal for the patient.

The fatty deposits which are made of fats play a big role in the development of CHD. One of the fats that have impact is saturated fats. Saturated fats are a fatty acid with single bonds between the carbon atoms containing extra hydrogen. Saturated fats are able to raise the levels of cholesterol in your blood. High levels of cholesterol are the key factor of plaque formations which cause CHD.  Another fat is the unsaturated fatty acid which consists of one or more carbon bonds. However, unsaturated fats can assist to decrease high cholesterol levels in the bloodstream and simultaneously lowering the risk of heart diseases such as CHD. Another fat that plays a big role in CHD are trans-fatty acids which are a result of the hydrogenation process from oils. According to the American Heart Association, the trans- fats will increase the harmful (LDL- low density lipoprotein) cholesterol levels but lower the good (HDL – High density lipoprotein) cholesterol levels. This Association also states that the consummation of trans- fats will increase ones’ risks of developing heart diseases such as CHD, strokes, and type 2 diabetes.

Figure 3 - This diagram shows an artery under high
blood pressure. The blood pressure is high enough to
damage the walls of the artery and the heart.

There are many factors which increase ones chances of developing heart diseases such as high blood pressure, smoking, obesity and stress. The blood pressure is one of the factors that leads to CHD since if the blood pressure is constantly high it can damage the heart and aid to develop plaque in the artery walls. Obesity or overweightness raises risks of CHD and other issues people who suffer from obesity have other preexisting factors that contribute to the development of heart problems through high levels of cholesterol, triglyceride, diabetes and blood pressure. Smokers also have a higher chance of developing CHD because tobacco triggers a buildup of plaque on the artery walls. Smoking can also cause blood clots which could potentially lead to heart attacks. Stress, anxieties and other similar issues may trigger one’s arteries to tighten. Therefore the blood pressure would increase potentially establishing CHD.

Works Cited: 

"What Is Coronary Heart Disease?" - NHLBI, NIH. N.p., n.d. Web. 20 Jan. 2016.

"Coronary Heart Disease Risk Factors." - NHLBI, NIH. N.p., n.d. Web. 20 Jan. 2016

"Good vs. Bad Cholesterol." Good vs. Bad Cholesterol. N.p., n.d. Web. 21 Jan. 2016.

"Trans Fats." Trans Fats. N.p., n.d. Web. 21 Jan. 2016.

Allott, Andrew. IB Biology Course Compagnion. N.p.: Oxford, n.d. Print.

Coronary Heart Disease

Matija Draskovic

Biology 11

1/18/2016

Coronary Heart Disease

The heart like any other muscle in the human body requires adequate blood supply in order for then it to provide the rest of the body with oxygen. This then allows the muscles to contract and to pump. Due to the blood pumping, it provides the whole body with enough blood, and not only does it do this with the rest of the body it also pumps blood to the heart itself. Since this is a very fragile process the heart is open to major heart diseases, one of them being coronary heart disease.

What is Coronary Heart Disease?

Coronary heart disease (CHD) is when the small blood vessels that supply blood and oxygen to the heart narrow down, and become tighter, as seen in figure 1. This is due to the buildup of plaque in the arteries that become narrowed by a gradual build-up of fatty material within their walls. “This condition is called atherosclerosis and the fatty material is called atheroma” (http://www.nhlbi.nih.gov/health/health-topics/topics/cad). Thus arteries become harden and therefore the transmission of blood through these arteries slows down or stops entirely. If blood was to stop or in other words if the arteries was clothed up angina or a heart attack are possible to occur.

Figure 1: Shows the heart and the blockage of the blood flow by the plaque (fatty acids)

What are the risk factors?

Many risk factors resulting in coronary heart disease include the diets that people intake, along with other important factors, like unhealthy blood cholesterol levels: this includes high LDL cholesterol (which is referred to as “bad” cholesterol) and low HDL cholesterol (otherwise known as “good"). Along with these risk factors others include: high blood pressure, smoking, insulin resistance, diabetes and lack of physical activities (http://www.nhlbi.nih.gov/health/health-topics/topics/cad/atrisk).Foods that contain high saturation and tran fats, sodium, cholesterol and many of the other risk factors I have mentioned above can add on to the risk of obtaining coronary heart disease, which will most likely lead to a heart attack. People who are more likely to suffer from a heart disease should therefore substitute each one of these fatty acids with other healthier options. Diet is therefore the key to curing or rather treating CHD. The good and the bad news about these risk factors are that some are changeable while others irreversible.

Figure 2: Shows how cholesterol blocks the heart artery and slows down the transmission of blood

Symptoms based on CHD

Symptoms that usually/generally follow this type of disease (CHD) are chest pain or discomfort. People have told that it feels as if “you have someone squeezing your heart”. This may be felt underneath the sternum, neck, arms or stomach. This is generally known as angina. One of the ways to test your heart activity is through an EKG scan, which is the most common/reliable and least painful method (http://www.webmd.com/heart-disease/electrocardiogram). Doctors usually test your heart activity in order to receive information about your conditions.  Along with EKG scans, stress testing is a great way in order to see if there is irregularity with the way your heart beats, or generally your heart. Other ways include x-rays and blood samples.

Why is finding results for CHD difficult?
Even though we can get information data regarding CHD from animals, they do not necessarily resemble the same causes in humans. While human experiments is also possible, many people are not prone to following strict diet plans and exercises, they would rather risk their health in order to enjoy bad habits. Since DNA can also effect CHD in different people finding a group of people with similar genetic material could be close to impossible, unless the person has a fraternal twin.

Treatments and Prevention 

The best treatment and protection from this disease is to live a healthy lifestyle. Quitting smoking and eliminating fatty foods is the first step to treating CHD.  If an individual has a more severe condition, actions such as, medication, and surgery (like EKG) are crucial for further treatment of the disease.

Figure 3: Shows a normal heart in comparison to the sick one

Word count:634

Bibliography: 

   
        Allott, Andrew, and David Mindorff. IB Biology. 2014 ed. Oxford: Oxford U, n.d. Print.

     "Coronary Heart Disease: MedlinePlus Medical Encyclopedia." U.S National Library of Medicine. U.S. National Library of Medicine, 8 Dec. 2014. Web. 20 Jan. 2016. <https://www.nlm.nih.gov/medlineplus/ency/article/007115.htm>.

  "Coronary Heart Disease." - Heart Health. N.p., n.d. Web. 20 Jan. 2016. <https://www.bhf.org.uk/heart-health/conditions/coronary-heart-disease>.

       "Coronary Heart Disease Risk Factors." - NHLBI, NIH. US Department of Health and Service, 23 Oct. 2015. Web. 20 Jan. 2016. <http://www.nhlbi.nih.gov/health/health-topics/topics/hd/atrisk> 

       

        "How Can Coronary Heart Disease Be Prevented or Delayed?" - NHLBI, NIH. US Department of Health and Service, 23 Oct. 2015. Web. 21 Jan. 2016. <http://www.nhlbi.nih.gov/health/health-topics/topics/cad/prevention>.

        "What Is an Electrocardiogram (EKG or ECG) Test?" WebMD. WebMD, n.d. Web. 20 Jan. 2016. <http://www.webmd.com/heart-disease/electrocardiogram>

              

         

Factors Leading to Coronary Heart Disease (CHD)

As of 2010 the leading cause of death is coronary heart disease resulting in over 7 million deaths. Coronary heart disease or short CHD is a heart disease which is caused by gradual build up of fatty material inside the coronary artery which supply's the heart with oxygen as show in picture 1.

Picture 1: Coronary Heart Disease

The arteries get narrowed stopping the red blood cells to reach the heart. This process is is called atherosclerosis and the fatty material is called atheroma. The fatty material that builds up in the arteries is mostly low density lipoprotein (LDL) or bad cholesterol. Lipoprotein is a molecule that carries cholesterol throughout the bloodstream. Cholesterol is a fat that is produce by the liver from the saturated fat in the diet.

There are many factors that lead to coronary heart disease. One of them is obesity. If people are obese they have a greater chance of heart failure because fatty material build up more gradually since they intake more fats in their diet than they need. There is a greater chance of a blood clot and a stroke because there is too much fatty material on artery walls.

Obesity also raises blood pressure which also affects the chance of getting a stroke. Since the heart pumps faster and stronger in order to get enough blood it builds up pressure inside the arteries which can damage them and make them weaker. High blood pressure can also be cause by stress even if you are not obese. Your heart will work faster and the pressure will still raise.

Another factor that causes CHD is smoking. Smoking can damage lining of arteries making it easier for fatty material to build up. Also the carbon-monoxide from cigarettes can decrease the amount of oxygen in the blood which makes the hearth pump stronger raising the blood pressure. Also nicotine increases the level of adrenaline in the body which makes the heart beat faster which also raises blood pressure. Blood is also more likely to clot.

People who have diabetes have a much higher chance of getting CHD than people without it. Diabetes causes high levels of glucose in the body which affects the strength of artery walls and makes them more likely to develop fatty deposits.

High levels of cholesterol can also cause CHD. There are two types of cholesterol. The LDL as mentioned before and HDL. HDL is a high density lipoprotein which is also known as good cholesterol. While LDL builds up on the artery walls HDL is cleaning it. It is due to the structure of the lipoproteins as shown in picture 2. High concentration of triglyceride makes LDL stick to artery walls while HDL structure, which contains more protein is dissolving it. The lower the level of HDL the bigger the chance of getting CHD.

Picture 2: Structures of HDL and LDL

Coronary heart disease is the leading cause of death as of 2010. Research is being done in order to prevent it by the American Heart Assosiation.


Bibliography:

"Prevention of Sudden Deaths from Heart Disease." American Heart Journal5.3 (2010): 386. Web.

"Diabetes and Your Heart." Diabetes. N.p., n.d. Web. 22 Jan. 2016. <https://www.bhf.org.uk/heart-health/risk-factors/diabetes>.

"Smoking." - Heart Health. N.p., n.d. Web. 22 Jan. 2016. <https://www.bhf.org.uk/heart-health/risk-factors/smoking>.

"Coronary Artery Disease - Coronary Heart Disease." Coronary Artery Disease - Coronary Heart Disease. N.p., n.d. Web. 22 Jan. 2016. <http://www.heart.org/HEARTORG/Conditions/More/MyHeartandStrokeNews/Coronary-Artery-Disease---Coronary-Heart-Disease_UCM_436416_Article.jsp#.VqFMCfmrTIU>.

"HDL Cholesterol: "The Good Cholesterol"" WebMD. WebMD, n.d. Web. 22 Jan. 2016. <http://www.webmd.com/cholesterol-management/hdl-cholesterol-the-good-cholesterol>.

"LDL Cholesterol: How It Effects Your Heart Disease Risk." WebMD. WebMD, n.d. Web. 22 Jan. 2016. <http://www.webmd.com/cholesterol-management/ldl-cholesterol-the-bad-cholesterol>.

"Obesity and Heart Disease." Obesity and Heart Disease. N.p., n.d. Web. 22 Jan. 2016. <http://circ.ahajournals.org/content/96/9/3248.full>.

"Coronary Heart Disease - Causes ." Coronary Heart Disease. N.p., n.d. Web. 22 Jan. 2016. <http://www.nhs.uk/Conditions/Coronary-heart-disease/Pages/Causes.aspx>.

"Heart Disease and Stroke Statistics-2015 Update." Heart Disease and Stroke Statistics-2015 Update. N.p., n.d. Web. 22 Jan. 2016. <http://circ.ahajournals.org/content/131/4/e29.full.pdf+html>

Factors that lead to CHD

Aron T.

Biology 11

1/20/2016

Factors That Lead to Coronary Heart Disease

Coronary Heart Disease (CHD) is when blood flow to the heart is temporarily or permanently blocked. This is problematic to the wellbeing of one’s heart, because blood transports the materials (nutrients, minerals, oxygen) that are required for heart muscles (or any muscle) to contract and sustain the life of those cells. Caption #1 shows the muscles in the heart that are affected by CHD. Coronary Heart Disease can be caused by the buildup of plaque (cholesterol) in the arteries which direct blood to the heart, and by the increase in blood pressure.

Caption #1: Shows the muscles that are damaged by CHD	Caption #2: Shows the changes on a fatty acid after hydrogenation.

Plaque building up in the arteries, also called atherosclerosis, is mainly affected by one’s diet, specifically in the ingestion of lipids. The lipids that are likely to cause CHD are: saturated fats, and trans fats. Trans fats are created artificially from hydrogenated vegetable oils, which would usually be unsaturated, which changes the physical properties of the lipids. Caption #2 shows how the hydrogenation of an unsaturated fat results in a saturated fat that has hydrogen atoms added to its structure. The physical changes allow trans fats to become solid at room temperature. Trans fats also increases LDL (low-density lipoprotein) cholesterol in the body, while decreasing the concentration of HDL (high-density lipoprotein). LDL and HDL transport cholesterol through the body, and LDL is considered to be negative since it contributes to plaque (cholesterol) buildup in arteries.

Caption #3: Shows the results of hypertension on blood vessels.

CHD can also be caused if the blood pressure of an individual is too high, which can be caused by the ingestion of salts. High blood pressure causes hypertension, which accounts for the slight damage to blood vessels and can cause blood vessels to narrow. The narrowing of blood vessels may also contribute to plaque (cholesterol) and fat buildup (atherosclerosis) in the arteries. Caption #3 shows how an increase in blood pressure can affect the buildup of plaque (cholesterol) in blood vessels.

Other factors that can help the rate of CHD, which are not diet related, may be seen as: smoking, physical inactivity, and diabetes. Smoking regularly may raise blood pressure (caused by nicotine), damage the lining of one’s blood vessels, and (similar to trans fats) increases LDL while lowering HDL. Physical activity can help reduce the risk of CHD by regulating blood pressure and the levels of lipids in blood cells. Without regular physical activity, these benefits are not being exploited, and a high blood pressure and high lipid concentration may lead to CHD. Diabetes is a risk for CHD because it promotes high glucose levels in blood cells. This is because the hormone insulin, that helps transport glucose to other cells, is not being created or isn’t being used properly. The result could be an abnormal level of sugar in blood cells. These symptoms can lead to CHD, because it also promotes hypertension and abnormal lipid levels in the body.

While scientists have found connections with trans fats, and other lipids, to CHD, there are often many roadblocks in the development of this research. Human volunteers for the experiment would have to undergo certain diets and exercise, which might be hard to sustain over long periods of time (Allott/Mindorff 84). The outcome of the experiments could also be affected by the patient's’ DNA, and finding a group with the same genes would be difficult (Allott/Mindorff 84). While scientists have also tried to experiment on animals, the data collected would not necessarily fit symptoms for humans (Allott/Mindorff 84).

Word Count: 591

Bibliography

"About Heart Disease." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 2015. Web. 21 Jan. 2016. <http://www.cdc.gov/heartdisease/about.htm>.

"Cardiovascular Disease Risk Factors." Cardiovascular Disease Risk Factors. Web. 21 Jan. 2016. <http://www.world-heart-federation.org/cardiovascular-health/cardiovascular-disease-risk-factors/>.

"Trans Fats." Trans Fats. American Heart Association. Web. 21 Jan. 2016. <http://www.heart.org/HEARTORG/HealthyLiving/HealthyEating/Nutrition/Trans-Fats_UCM_301120_Article.jsp#.VqDgLPkrLIU>.

"Good vs. Bad Cholesterol." Good vs. Bad Cholesterol. American Heart Association. Web. 21 Jan. 2016. <http://www.heart.org/HEARTORG/Conditions/Cholesterol/AboutCholesterol/Good-vs-Bad-Cholesterol_UCM_305561_Article.jsp#.VqDh8PkrLIU>.

"Basics About Diabetes." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 2015. Web. 21 Jan. 2016. <http://www.cdc.gov/diabetes/basics/diabetes.html>.

Allott, Andrew, and David Mindorff. IB Biology. 2014 ed. Oxford UP. Print.

Coronary Heart Disease

Fatty Acids, Good or Bad? 

by Celine Ernest

Figure 1- Shows the different stages from being anorexic to obese and vise versa.

It is important for us humans to stay well nourished, in other words, keeping a healthy diet. Staying well nourished depends on the foods and drinks a person consumes daily. Fats can however affect peoples lives, while on the other hand people can lack levels of fats that affect their lives as well. For example, there are mental and physical circumstances connected to eating. A person can discover a psychological condition that involves voluntary starvation, which then leads to a loss of body mass. The condition is called anorexia nervosa, anorexia is the third most common psychological condition amongst teens. Anorexia has affected the majority of the population as it is the most common cause of death. The opposite of Anorexia is Obesity, when a person is obese they tend to intake more goods (usually considered to be unhealthy containing unhealthy fats), without any additional exercises. Obesity can lead to coronary heat disease and type two diabetes, CHD reduces life expectancy, as well as increasing health costs. "More than 35% of U.S adults are obese.". Both conditions are caused by either the lack of fats or the excessive intake of fats as shown in Figure 1. 

Figure 2- Displays the Saturated fatty acid and the Unsaturated
Fatty Acid. As shown above Saturated fatty acids contain single
bonds whereas Unsaturated fatty acids one or more double bonds.

 Fatty acids are part of the carboxyl group (-COOH). A long hydrocarbon chain made up of a chain of carbon atoms with hydrogen atoms liked by single covalent bonds. The chain can be up to 14-20 atoms long. The chain is either saturated or unsaturated. Saturated fatty acids contain single bonds between all carbon atoms, therefore containing a lot of extra hydrogen. Unsaturated fatty acids is when the molecule contains one or more double bonds. However trans fats or trans-unsaturated fatty acids are uncommon to find but are produced artificially by hydrogenation of vegetable or fish oils. According to Harvard T.H. Chan, trans fat raise LDL cholesterol levels and lower HDL cholesterol levels. Which means that once a person overly abuses trans fats, it will increase risks of developing heart diseases such as coronary heart disease. 

Figure 3- Shows the difference between a normal
artery with a healthy blood flow, versus an artery
showing fatty plaque.

Coronary heart disease can be a side affect of obesity. Coronary heat disease, is when your coronary arteries become narrowed down by fatty material (atheroma) within their walls. The arteries affected are those that supply the heart with oxygen and rich blood. Over many years the build up of plaque occurs in the artery, which is called atherosclerosis. However, correlation has been found that saturated fatty acid does not affect rates of CHD. In the text book, they mention the Maasai of Kenya whom have a diet that is rich in meat, fat, blood and milk. Maasai do however stay active and work, and are in need of those fats in order to give them minerals, vitamins, and energy. And Maasai's do not have enough food to eat for Breakfast, Lunch and Dinner, meaning that the next meal can be in over a day or two. This additional information does show that their comparison is too specific and should be generalized to people who consume too many of the fats such as saturated fatty acids, cis- monounsaturated fatty acids, trans fat, etc. It all concludes to the importance of staying nourished, keeping active, having a healthy social life as stress can cause heart diseases too (chronic stress). Too much of a substance will always remain to be unhealthy as our body is in need of a balanced diet. 

Bibliography:

"How Many People Are Affected By/at Risk for Obesity & Overweight?" NIH, n.d. Web.

Allott, Andrew. Biology for the IB Diploma: Standard and Higher Level. Oxford: Oxford UP, 2011. Print.

"Anorexia Facts and Statistics - Futures." Futures of Palm Beach. N.p., n.d. Web. 20 Jan. 2016.

"The Truth about Fats: The Good, the Bad, and the In-between." Harvard Health Publications, 3 Feb. 2015. Web. 20 Jan. 2016.

Elena: Factors Leading to Coronary Heart Disease (CHD)

Coronary Heard Disease is a condition which defines the blockage of arteries that supply blood to the heart. Our heart is a muscle and cannot function without oxygen. The blood flowing through the arteries contains oxygen, therefore the blockage of these arteries leads to the dysfunction of our heart muscle. As visible in figure 1, an artery of an individual with the condition of CHD has a lower rate of blood supply due to the clotting within the artery, while an individual that does not suffer such disease provides the heart with maximum supply of blood.

Figure 1: comparison beween a healthy and clotted artery.

Figure 2: Human heart diagram with labelled coronary arteries

 In figure 2, we can see that there are two main coronary arteries in the human heart, the left and the right, which separate into many smaller arteries in order to distribute the oxygen-filled blood throughout the entire heart.

However, once there is blockage in one artery, that doesn't cut down the circulation of blood throughout the entire heart, but only that particular part of the heart. This partial blockage leads to severe chest pain, which spreads towards the shoulders, arms, neck, upper back, the general area around the chest. This pain is also known as angina. However, if there is blockage in both main arteries, a heart attack occurs, which if strong enough may lead to death.

There are many ways that an unhealthy lifestyle leads to heart disease, such as smoking, diabetes, or obesity. A person's diet with high doses of cholesterol or fat causes plaque, also known as patches formed that cause clotting, to form on the inside of arteries, taking up space, therefore preventing blood flow. This condition is also known as atherosclerosis. On the other hand, CHD isn't only caused through and unhealthy living, sometimes there are genetic factors that determine the situation, and also aging. When we age, it is very possible that our artery walls form a more fixed, less elastic shape and become less flexible, limiting the efficiency of blood flow.

The usual symptom of CHD is angina, as mentioned above. However, there is a way of testing your heart activity in order to draw a reliable conclusion. One of the least painful and reliable ways to test your cardiovascular health is through an electrocardiogram or EKG test. Stress testing is also another way to test your health. Whether the stress testing shows abnormality in one's blood pressure or heart rate, length of breaths taken or condition of the chest pain, it is likely one is diagnosed with CHD. Other ways doctors test this disease is through blood samples and X rays as well.

Figure 3: ways to treat coronary heart disease (medications,
angioplasty, and surgery).

The positive aspect is that there are medications and ways to improve your daily life and treat this condition. The main way to not only treat, but also avoid CHD is by making healthy diet and life choices, which include avoiding smoking, forming a low fat, salt and sugar diet, and exercise. On the other hand, if one;s condition is much more severe and cannot be cured with only changing their lifestyle, medications will be suggested by a doctor which will raise the level of oxygen within an individual's blood stream and cause their heart to work more efficiently. Lastly, another way that severe heart conditions are cured is through surgery, all including the increase of blood supply to one's body. Figure 3 provides a visual representation of three effective ways to treat this disease. As already mentioned, medication and surgery, but also angioplasty which has multiple methods to insert tools inside the artery and separate the plaque into small fragments that are later washed away by the blood.


Works Cited:

"How is coronary heart disease diagnosed?" National Heart, Lung, and Blood Institute. N.p., n.d.Web. 21 Jan. 2016. <http://www.nhlbi.nih.gov/health/health-topics/topics/cad/diagnosis>.

"Coronary Heart Disease." British Heart Foundation. N.p., n.d. Web. 21 Jan. 2016.<https://www.bhf.org.uk/heart-health/conditions/coronary-heart-disease>. 

"Heart Disease Health Center." WebMD. N.p., n.d. Web. 21 Jan. 2016. <http://www.webmd.com/heart-disease/guide/heart-disease-coronary-artery-disease>. 

"Cholesterol Health." BergaMet. N.p., n.d. Web. 21 Jan. 2016. <http://bergamet.co.uk/cholesterol-health>. 

"Treatment of Coronary Artery Disease." Heart Point. N.p., n.d. Web. 21 Jan. 2016.<http://www.heartpoint.com/treatcoronaryartdis.html>.