Today I have a great news for the people who are a type of computer geek. Microsoft had announced that soon they will release the Windows 8 version for the public to buy on October 26, 2012. Microsoft had already released the Windows 8 Developer and Release Preview. If you want to feel the windows 8 before it is commercially launched, then you can download the Windows 8 Release Preview from the link below:
But remember to use dual boot setting to run windows 8 with windows 7 as it is said that Windows 8 Release Preview can be buggy and can stop working suddenly. Below is the link from where you can learn how to do dual boot:
But is don't like the Windows 8 Release Preview, then you might require to wait till October 26, 2012. But don't worry, because Microsoft had also announced that it will be releasing the Windows 8 RTM version which would be just like the commercial version for the Manufacturer's of Windows 8. So if you have some friend or relative working in the Microsoft then you can ask him to give you a look at it or just install it on your computer.
Today Stanford will tell you about the types of strokes in our brain. Just watch the video below:
Here are the notes that you can revise after watching the video:
Neurons communicate through Ions. Ions are passed through the cell membrane and the inside of the cell is negatively charged while the outside is positively charged. The neurons send electric signals to communicate known as action potential. The difference between the cell's inside and outside atmosphere is maintained by the proteins in the cell membrane.
They do so by pumping certain ions inside and certain ions outside,this pumping actino requires energy.
Neurons only work in aerobic conditions and they don't have their own energy stores. Brain only costs 2% of body weight, but requires about 20% of cardiac output, and 15% of oxygen take from the lungs. The blood to the brain reaches from the aorta is taken up to the brain by the carotid artery,
which takes 70% of it. The other 30% is taken up by basilar artery and verebral artery. This two artery are joined the base
of the skull and are then divided into six parts (2 parts each) -
The Circle of Willis is the place where all these arteries join to provide the brain with blood. This circle joined the right and left artries so that if one artery (either left or right) is not working, then the brain will still receive the blood instead of no blood. Now there are also many other deeper parts in our brain, this parts will get supplied by different arteries. If this arteries don't work properly, that certain part might not be able to function properly.
For example, if the blood does not reach the Broca's and Wernickel's area, this parts will stop working and that person might suffer from Broca's Affesia, a disease in which that person will have language related problems.
A stroke is defined to be an abrupt onset of focal or global neurological symptoms, caused by ischemia or hemorrhage.
Ischemia means restriction of blood in Greek. And it is usually caused due to factors in blood vessels, with resultant damage in tissues. Tissue damage is caused by shortage of O2 or Glucose.
Hamorrhage is discharge of blood from blood vessels AKA bleeding. Bleeding in the tissue or around the brain. Their are 3 types of strokes, Ischemic stroke, Intracerebral Hemorrhage, Subarachnoid Hemorrhage. Ischemic Strokes are usually caused by blood clotting in the brain which will result to no O2 and glucose supply to the brain. Intracerebral Hemorrhage is bleeding in the tissues and Subarachnold Hamorrhage is bleeding around the brain.
Warning signs of Stroke:
1. Sudden Numbness on the face or any other body part, especially on the one side of body.
2. Sudden Problems in speaking or understanding.
3. Sudden, severe headache with no known cause.
4. Sudden trouble walking, loss of balance or coordination, dizziness.
5. Sudden trouble seeing with one or both of our eyes.
If a patient walks in and says he/she has a stroke, we can do the image studying of the brain to confirm that, the images show us what type of stroke it is or either it has an other cause such as tumor, infection, epilepsy. Imaging also tells us how better the brain is getting blood from the blood vessels. Their are two methods of Imaging, MRI an CT scan.
We can also use the cerebral angiography scan to determine the stroke. The main symptomes of strokes are usually seen in people with High blood pressure, diabetes, people who smoke, drink or intake tobacco.
Ischemic stroke is caused when the thrombus is formed which leads to vessel occulsion leading to O2 depletion leads to membrane ion failure which leads to cell swelling and then cell death. Some thrombi take time to form but there are some other thrombi that are formed in the heart and are then sent to the brain from the heart. Some strokes can also be temporary but we must remember that they may be a sign of a stroke. tPA is a method to diagnose the deficits of stroke, but it is not very much effective. The occulsion of a cerebral vessel is followed by formation of a central irreversible infarct, with a peripheral zone, the penumbra, where the tissue is variable due to partial preservation of blood supply via collateral vessels. CT Perfusion shows up the penumbra and infracted area. CT Scanning uses the X-Rays to make a
photo of the brain, the X-Rays are projected to the patient by the X-Ray generator which rotates around the patient to get a good view of the brain, the image of the brain is regerated by a process known as Back Projection as the X-Rays are changed in velocity when they interact with the tissues. MRI works with the help of the photon molecules or molecules containing photons, the MRI take advantage of the photon as they spin at a certain frequency at certain chemical environment, so we use different photons for different tissues, the photons when are bought in an magnetic field, then releases some enery as protons which we can record as they pass through the tissue to get an image of the brain. Rcently, Stanford University and other Universities have made a device that can go through the artery and the surgeon will pass the
device until the surgeon see's the thrombus, afterward's, the device will pull out a string through the clot, and will then turn the string into spiral shape so that the thrombus is stuck in it without any problem and will then just drag the thrombus with the help of the string and take it out. Another thrombactic device is also there that can relatively suck the clot in it and then the device can be taken out of the artery. If the thrombus is sent through the heart, after it is removed, there are sligth chances that the heart might send another thrombus again, which would again cause the ischemia. To make sure that this does not happen, the patient is passed through certain medication after the thrombus is removed from the artery.
The cerebrovascular system is the only route for energy supply to the brain. Blood vessels are lining organs that are under constant state of vascular remodeling. Acquired and cognital problems of this system are important causes of stroke.
In hamorrhage, the blood vessels spell the blood in or around the brain, and as a result of that, that particular vessel does not supply that particular brain part with which it is associated and this leads to ischemic stroke. More people die because of hamorrhagic stroke than the ischemic stroke. The causes of hamorrhage are divided into Primary and Secondary causes, primary cause of hamorrhage is hypertension etc. Ischemic stroke can also be converted to hamorrhage as in
ischemic stroke the blood is not able to reach in the brain which can make the vessel blast as the thrombus won't allow the blood to pass through the artery and then the artery will not be able to take on the blood pressure and will blast off.
Ischemia can also lead to hypertension which would lead to hamorrhage. Surgery is the best way to treat hamorrhage but there are chances of accident in surgery which can lead to brain damage. Aneurysms are the defect in blood vessels where the blister's form. We don't know why the aneurysms occur. The people who suffer from aneurysms have brother's and sister's who also suffer from this aneurysms, this makes us think that there is some genetic problems related with it. The larger the aneurysms the bigger the chance to blow. There are several causes of SAH (Subarachnoid Hamorrhage) such as hypertension, alcohol, pregnancy, drug or cocaine, smoking.
Aneurysms usually happen where two arteries join. Aneurysms can be found in a Stroke, Seizure, or a headache pain.
We can tell if a patient has SAH if he is reporting a very worst headache of his/her life, nausia, vomiting, photophobia, neck pain, less control over eye or face, altered level of consciousness, sential headaches (warning leaks) may proceed major, clinically divastating SAH as in half of the cases. First thing to diagnose a SAH is to get an angiographic study of it. We can also do a 3D angiogram. We can treat aneurysms by surgery and enduvascular coiling. In the surgery, we first make a small window in the scalp to look inside the brain, and then we look through a microscope in it, find the aneurysms and then tie a clip around the aneurysms, this would not allow the blood to get into the aneurysms and so the aneurysms
will not bleed out. In endovascular coiling, we tie the aneurysms from the bottom to the top so that the blood can't enter into the aneurysms. The coil comes of different types and sizes. The endovascular coiling can be done with the Primary treatment, Ballon assisted treatment, and Stent assisted treatment. In primary treatment where the neck is not to much large, we just coil the aneurysms, but in ballon assisted aneurysms, we need to use a ballon so that the coil did not fall back to the vessel. There is a device known as flow diverter that can divert the flow of the blood into other blood vessel so that the surgeon can perform the surgery. Arteriovenous Malformations is an abnormal collection of blood vessels wherein
the arterial blood flow directly into the veins without proper capillary beds. Cognitial , but may enlarge with age, this may involve an abnormality or dysregulation of vascular development or remodelling. Usually in AVM's, they are seen like very large capillaries and the veins in AVM usually loss the two layers of their walls, as well as we are not able to see the brain tissue between them, this condition is named as enciephalomalacia. This may be due ischemia at that place or due to the hamorrhage as the veins are carrying blood at high pressure and they are not accustomed to it. This disease usually
is diagnosed at the adulthood as it starts creating problems at that time and it is a rare disease (1-2 people per 100,000)
We use CT (CT Angiography),MRI (MR Angiography), or angiogram to find AVM's. We can cure AVM's by using microneurosurgery, which is very good method for curing the less sophisticated AVM's as well as which are located on the upper side if the brain. AVM's might have been in the patient from their birth or it might have been developed with age but it usually is within the patients at their time of birth. The AVM usually occur when the capallaries are not able form the correct way and they grow thicker and thicker with the time. The AVM can also be treated with the help of Stereotactic Radiosurgery, in this process the AVM is cured with the help of radiation and this is only done when we usually cannot acces the AVM
surgically. We use Endovascular Embolization to make the microsurgey or the Stereotactic Radiosurgery more effective and this all is known as Multimodality approach,i.e., using two or three methods together to cure the Anteriovenous Malformation. The CyberKnife Radiosurgery is made by the Stanford Scientists and it is used to target the particular area directly by an image guided robot. Embolization helps us to get a 3d graph of the brain or the Anteriovenous Malformation as well as helping us to decide weather it is okay or not to do an surgery. We can also know about the risks of performing
a surgery there and also introduce flow-directed micro catheters to the patient's body so that will be assisting in the furture processes as well as to inject liquid in the blood which can literally block that portion of the blood vessel(AVM).
Galen AVM is a type of Anteriovenous Malformation in which the AVM is much dilated than the usual.
Just few days ago, I was having a problem with my sub - woofer on my pc as it was not working. I tried to search on the google about this but I was not able to find any answers in it. They all said that it might be an problem in the wiring or an sound card defect. But I tried every thing and nothing works. But I got it working, here's how:
First check if you have installed the right driver on your pc for the sound card or not. To check that, just see the speaker icon on the lower right corner of you moniter, if the speaker is with a red cross, this means that you have not installed the driver, install the correct driver or call the person from whom you bought the PC to know which drivers you need. Or if the speaker is with a stop sign with it, that means that you have accidentally turned off the volume. To turn it on, just drag the bar to the top.\
(To perform this step, first close the PC and the UPS) If Step 1 does not work, then you might not be knowing that the sub - woofer also requires power to run which it usually gets from the UPS. Many people forget about it and buy a new Woofer. The thing you need to check here is that look at the back the sub - woofer and you will find a wire in it, other than the speaker wire or the CPU one, follow that wire and see at which socket is it installed, after you have turned the UPS off, then just remove the pin from that socket and replug it or try to use another working socket, this would give your woofer the power supply and you will be able to use it again.
If the Step 2 don't work, then I recommend you to concern a professional in it.
Thanks for reading and I hope that your Sub - Woofer will work.
Today I will be teaching you how a cell divides. First, I would like to tell you an amazing fact about cell division, our human body cells divides about a thousands of time in one minute. I found it very amazing and I think you will also find it also amazing.
Now let's get into the cell division process. First I need to tell you that the germ cells and somatic cells are the two classification of the cells in our body and these cells divide in different ways. Germ cells a.k.a. Gamete cells are the cells that are reproduction cells, such as ovum in women and sperm in men. And somatic cells are the cells that do not reproduce.
Their is one common phase in the Cell cycle that both the cell types undergo that is interphase. There are three phases in the interphase. They are:
G1 Phase.
S Phase.
G2 Phase.
In the G1 Phase is the phase in which the cells start to divide. In this phase they just start the centrosome( An important part of cell) division and in this phase the cell is metabolically active and also the cell starts the division of cytosolic components.
During the S phase, the cell starts DNA replication, so that each type of new cell formed gets equal number of genes. Genes are a very important part of our cell, they are like the General Governor of the cell Army, each and every action usually starts from them. So, it is important that the genes must be divided equally so that the cell is able to perform the right way. The genes are the building units of the DNA.
During the G2 Phase, the centrosome replication is complete and the the DNA replication is also complete. At that time, the cell is usually synthesis proteins and other enzymes. But to be remembered that if some cell don't divide and the they are just locked in the G1 phase and are said to be in the G0 phase.
Interphase.
Now let's discuss about the mitosis and meiosis. The somatic cells divide through mitosis process and the germ cell divide through meiosis. First let's talk about mitosis, the mitosis is the process of cell division the includes 4 phases. Prophase, Metaphase, Anaphase, telophase.
In the Prophase, the cell starts dividing itself by first converting the Chromatids into Chromosomes. This is an important part as each cell should have the same amount of Chromosomes to perform the right way. Also in this stage, the cell's nuclear envelope breaks up and nucleoli disappears. The nucleoli is a part that is located within the nucleus of the cell. And the nuclear envelope protects the nucleus. And also in this phase the mitotic spindle starts to form. The mitotic Spindle is an important thing without which the cell could not divide.
To understand the process of mitosis better, here is an image :
Mitosis.
In the above image, we can see the full process of mitosis. In the image, the red and green marks indicate the chromosomes. The next phase is the Metaphase, the chromosomes are held together by centrosome, outside of the centrosome have a protein known as Kinetochore, the mitotic spindle attaches to them, and arrange them in a single line known as metaphasic plate. Then in the next phase, the chromosomes are separated into chromatids and they are pushed to the other side of the cells by the mitotic spindle. In this way, both the new cells will be having the same amount of chromatids. The next and the last phase in the process of mitosis is the telophase, in this phase,the nuclear envelope reappears and the parent cell is like pinched out in between to form the two new haploid cell.
The cytokinesis usually starts at the late anaphase and starts to divide the cytoplasmic material. It is usually completed in the telophase but the distribution is usually done roughly.
I will be writing the process of miesosis on later times because I think remembering this much today is still okay for you.
