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Is transmission of HIV a chain reaction?
HIV Chain Reaction In that one person is infected by another, then infects a third person, who then goes on to infect another person, yes, HIV is a chain reaction. It is spread through human conctact and transmission of the virus through the blood and body fluids.
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Answer . The assassination of Franz Ferdinand led to Austria-Hungary declaring war on Serbia which led to Russia mobilizing, followed by Germany declaring war on Russia, wh…ich led to Germany invading Belgium, followed by Germany declaring war on France, followed by Britain declaring war on Germany.. This chain started with the assassination of Franz Ferdinand and all of these powers were pulled into WWI by treaties and alliances made with other European powers.
The polymerase chain reaction (PCR) is used to amplify DNA samples so there are enough copies present to do further experiments.
Polymerase chain reaction (PCR) is used to amplify nucleic acids. It was invented in its current form by Kary Mullins in 1983/1986. The template (DNA or RNA) is duplicated b…y a thermostable DNA polymerase - originally from Thermus aquaticus - using sequence specific primers (short single-strand oligonucleotides) that are designed to sit on either side of the piece of template that is to be amplified. Changes in temperature are used to move through the different stages required to duplicate the DNA. . 95Â°C denatures DNA to two single strands. . The temperature is decreased to ~50-60Â°C to allow the primers to anneal (bind) to the 5' end of the DNA templates - the exact temperature is 5Â°C lower than the primer's sequence-determined melting point (T m ). At the melting point half of the dissolved primers in solution would be annealed to the template DNA. . The temperature then climbs to 72Â°C where the polymerase adds dNTPs to the 3' end of the primer - most commercial DNA polymerases can elongate 1000 bases per minute. Some have "proof-reading" activity, where it can correct a wrong base it may have inserted. If the template is RNA then a reverse transcriptase is used - it reads the RNA, but makes DNA. . The reaction is heated again to 95Â°C to restart the cycle. After the last cycle the reaction is held at 72Â°C for a few minutes to ensure that all the strands are fully elongated. Each cycle duplicates the template, meaning an exponential increase in the amount of the target sequence. Usually, 30 cycles produce sufficient DNA for downstream applications. More cycles may produce more, but at some point the enzyme becomes less efficient or the dNTPs run out.
When a series of events occurs and each event was caused by the previous event, this is called a chain reaction. The domino effect is an example of a chain reaction.
The DNA fragment is placed into a thermocycler at 95°, this temperature breaks the hydrogen bonds between the double stranded DNA fragment. The thermocycler is then cooled to… 55°, this temperature allows primers that are added to anneal to the starting sequences of the two strands of DNA. Primers allow DNA polymerase to function. The thermocycler is then heated to 72°, where DNA polymerase is added. DNA polymerase then anneals nucleotides that are added to the template strands of DNA. Each cycle produces double the DNA that was inserted initially.
Heavy, unstable elements like Plutonium or Uranium has far more neutrons than protons intheir nucleus. When they are exposed to more neutrons, they become unstable and split u…p into lighter elements through fission. This releases more neutrons along with a lot of energy from the atom that split up. The released neutrons interact with more of the heavy atoms which repeat the reaction. This happens with all the atoms of the heavy element creating the chain reaction. Ultimately, what causes the chain reaction is unstable, heavy elements interacting with neutrons.
It allows us to make many copies of a targeted segment of DNA.
The control of the chain reaction in a nuclear reaction is accomplished in a number of ways, and this will depend on the reaction being controlled. In nuclear reactors, the mo…derator acts to slow down neutrons that are produced in fissions. And in the very common pressurized water reactors, the nuclear chain is controlled by the density of the water, which is a function of the temperature of that water. Let's take a quick look. A nuclear reactor (a pressurized water one) is idling at a few percent power while we roll the turbines and warm up the secondary plant. The control rods have been pulled to get us up to criticality and set up an average operating temperature in the core. The nuclear chain reaction is happening, and as these reactions release energy (and a few more neutrons), they heat the water. As the water gets hotter, it becomes less dense. The less dense water is less effective as a moderator (it doesn't slow down the neutrons quite as well), and as a result, more neutrons fail to slow down sufficiently. These neutrons, the "less slowed" ones, have a lower chance of causing another fission, and they escape. An equilibrium is established. As the main steam stops are opened, steam rushes down the headers and the turbines begin to spin. In the steam generator, the primary coolant that has been circulating there to make the steam comes back to the reactor cooler. That's because the feed pumps are pushing more cooler water into the steam generators as steam is being drawn off. That primary coolant returning to the reactor at a lower temperature is more dense, and is a more effective moderator. More neutrons are slowed down, and more fissions occur. More power is generated, and the reactor coolant leaves the reactor hotter and less dense. A new equilibrium is reached where the average temperature in the primary coolant is "back to normal" and more fissions are happening. More energy drawn off (taken out of the secondary system) has caused the primary coolant to more effectively moderate the reactor. More moderation means more fissions, and more power out. The temperature differential across the reactor is wider, but the average temperature is essentially the same. If you have been able to wade through all that, you know that the chain reaction in the reactor is controlled "automatically" by the amount of steam demand in the secondary system. The control rods are pulled to set up the initial conditions, and then the reactor core operates "by itself" to generate power. The chain is controlled by the amount of energy taken out of the secondary system.
If you're asking scientifically: A nuclear chain reaction (which is a continuous series of nuclear fission reactions) can only be controlled/stopped by a material that can abs…orb it. Think about it- during fission a nucleus splits into two (or more) fragments and releases two thing- neutrons and energy. The neutrons collide with other nuclei creating a chain reaction. I suppose a chain reaction can also be controlled if you find a way to take the neutrons produced away from a fissionable substance that relies on chain reactions to sustain itself so that the the substance isn't sustained and the chain reaction never takes place. But I'm not sure how to do that. :) I hope this help...
PCR can repeatedly duplicate a DNA (or RNA) fragment, so it's a chain reaction. After each cycle, PCR can repeat and repeat again to produce many copies of the same DNA segmen…t.
Unprotected sex accounts for the majority of new HIV infections. HIV is transmitted through contact with blood, semen, vaginal fluid or breast milk. While coming in contact wi…th an HIV+ person's blood carries the highest risk for infection, it is far more likely for someone to exposed during sexual intercourse to semen or vaginal fluid.
Dont share liquids with any other person. These are some examples of ways you can get these deseases: Kissing, sexual behavore, drinking after another person, being "Blo…od brothers" ect.!! Maybe its time we learn to stop doing these things.
Uranium produces spontaneous fissions in small numbers, and each fission releases two or three free neutrons, so there is always a source of neutrons present in any assembly o…f uranium fuel. If enough fuel is assembled, in a geometrical array with a moderator, the conditions are there to start a chain reaction, and this will happen whenever the reactor approaches what is called criticality, which is when the number of free neutrons present starts to reach a high level. The approach to criticality is controlled by slowly withdrawing the control rods, and if at stages the rods are held steady, the neutron flux also steadies out. As criticality is approached, the flux gets higher and when the rods are pulled a bit more beyond the critical point it will start to increase exponentially, the reactor is then said to be supercritical and the neutron flux will go on increasing with a certain doubling time. So with a nuclear reactor there is no need to do anything to cause "ignition" as in a coal furnace, it is just a matter of getting the amount of neutron absorber reduced to the point where the reactor is critical. Note that often a neutron source is loaded into the reactor as a permanent feature, this is done to enable the flux measuring instruments to see a reading during the approach to critical, but even without this the reactor will still start itself, if the rods are withdrawn.
A chain reaction is the continuation of a reaction initiated by the reaction itself. In some cases it is a closed reaction, where the repetition ends. In others, it will conti…nue until it exhausts the available reactants. A nuclear chain reaction would include 1) fission, where the neutrons released by a split atom travel outward and cause fission in other radioactive atoms 2) fusion, where the heat energy released by the reaction triggers the fusion of more atoms in a very hot and dense plasma A nuclear reactor moderates a safe fission reaction in a critical mass of radioactive material by allowing only a portion of the neutrons to reach other fissionable atoms. Otherwise, the reaction would cascade into a runaway criticality that would generate too much heat, melting and damaging the nuclear pile. In an atomic bomb, the chain reaction spreads to millions of atoms practically instantaneously. The reaction only lasts a fraction of a second but releases an incredible amount of energy.
In HIV and AIDS
No, circumcision does NOT prevent the transmission of HIV. Condoms can dramatically reduce the chance of HIV transmission. There's some evidence that circumcised men face a l…ittle less risk of catching HIV, but that's still far away from saying it's safe.