Electrical Conduction of the heart
The heart is an organ that pumps blood around the body that delivers oxygen to vital cells that undergo respiration. It is split into 4 chambers: Left Atria, Right Atria Left ventricle and right ventricle. When looking at diagrams the wall of the left ventricle is much thicker as the heart has to pump with more pressure to deliver blood around the body.
The rhythm of the heart is controlled by nerve impulse - Electrical excitation. Pacemaker cells are involved in controlling the rhythm of contraction. These are patches of specialised cells that control the contraction of the heart, consisting of SAN - (Sinoatrial Node) and AVN - (Atrioventricular Node). The Cardiac muscles that are found are known a: Myogenic meaning that they can contract on its own. Pacemakers SAN and AVN helps with the initiation and coordination of the heart.
Heart’s Electrical Conduction System
There is a short delay between SN and AVN which ensures that the atria has fully contracted and all the blood has gone to the ventricles. Otherwise if Atria and ventricles contract at the same time then blood will keep flowing up and down and won't leave the heart. However when pacemaker cells don’t work then we can have artificial pacemakers that can help with initiation and coordination with the heart.
The movements or the Electrical Activity can be monitored by doctors using an Electrocardiogram (ECG). Doctors can also check for any abnormalities in the rhythm of the heart beat.
We will continue in from the previous segment of this topic, in which we introduced nuclear weapons themselves and took a look at fission bombs.
The other primary type of nuclear weapon is fusion bombs. Fusions bombs are generally referred to as thermonuclear weapons or hydrogen bombs. These bombs rely on fusion reactions between isotopes of hydrogen, deuterium and tritium. All such weapons require a significant portion and sometimes a majority of their energy from fission. This is because a fission reaction is required as a trigger for the fusion reaction, and from their fusion reaction can themselves trigger additional fission reactions.
Thermonuclear bombs work by using the energy of a fission bomb to compress and heat fusion fuel. When a fission bomb is detonated, gamma rays and e-rays emitted first compress the fusion fuel, then heat it to thermonuclear temperatures. Thus ensuring reaction creates enormous numbers of high-speed neutrons, which can then induce fission in materials that are not normally prone to it, such as depleted uranium.
Since fusion reactions do not create fission by products, thus they contribute far less to the creation of nuclear fallout than fission reactions, but because all thermonuclear weapons contain at lesson one fission stage, thermonuclear weapons can generate as least as much fallout as fission only weapons.
Boosted fission weapon
This is a fission bomb that increases its explosive yield through a small amount of fusion reactions, but it is not a fusion bomb. In a boosted bomb the neutrons produced by the fusion reaction serve primarily as a way to increase the efficiency of the fission bomb.
A neutron bomb is a thermonuclear weapon that yields a relatively small explosion but has a relatively large amount of neutron radiation, such a device could theoretically be used to cause massive casualties while leaving infrastructure mostly intact and creating a minimal amount of fallout. The detonation of any nuclear weapons is accompanied by a blast of neutron radiation.
This is a device that surrounds a nuclear weapon with suitable material such as cobalt or gold. These bombs can produce exceptionally large quantities of long-lived radioactive fallout. It has been theorised that such a device could serve as a doomsday weapon because such a large quantity of radioactive material with half-lives of decades, lifted into the stratosphere where wind currents would distribute it around the globe, would make all life on the planet extinct.
Within recent news, the election of Donald Trump and the tensions within the middle east have seen the rise in threat of a nuclear war. The news and social media platforms have been constantly warning the general public about the threat of nuclear warheads. This article shall explain what is a nuclear bomb and its threat to humanity.
The definition of a nuclear bomb is an explosive device that derives its destructive force from nuclear reactions, such as fusion and fission (these have been explained in a previous article)
Both of these reactions releases a vast amount of energy. The first test of a fission bomb( also known as an atomic bomb) released the same amount of energy as approximately 20,000 tons of TNT or 84TJ. The first thermonuclear bomb (also known as a hydrogen bomb) released the same amount of energy as approximately 10 million tons of TNT or 42PJ. A thermonuclear weapon weighing as low as 1100 kg can produce e and explosive force of more than 1.2 million tons of TNT. Warheads the size of tradition bombs, can devastate entire cities by the blast fire and the radiation. Therefore nuclear weapons are known as Weapons of mass destruction of WMD’S, and their control has been a major focus of international relations.
Nuclear bombs have been used two times in Nuclear warfare, both time by the United States against Japan near the end of World War 11. These two bombs, that were dropped over Hiroshima and Nagasaki caused the deaths of around 200,000 civilians and military personnel
All current existing Nuclear bombs have some form of their explosive energy come from nuclear fission reactions. Weapons that have their energy come exclusively from fission reactions are known as atomic bombs. In fission weapons, a mass of fissile material ( a material capable of nuclear chain reactions ) such as enriched uranium or plutonium is assembled into a supercritical mass, which will be needed in order to start an exponentially growing nuclear chain reaction.
There are two methods of starting a fission reactions ; one is done by shooting one piece of sub-critical material into another, this is known as the gun method
Another method is by using explosive lenses , to compress the material so that it is many times its original density, this is known as the implosion device.
All fission reaction generate fission products, these are the radioactive remains of the atomic nuclei split by the fission reactions. These bombs are therefore a serious form of radioactive contamination, if not fully contained. Fission products are the principal radioactive component of nuclear fallout.
In the next segment of this mini-series we will look at fusion bombs and neutrons bombs
Woolly mammoths have sprung back into the news again in recent times, with news reports suggesting that they are “on a verge of resurrection” and will be back from extinction within two years. The statement was made by George Church, a lead scientist for the “Woolly Mammoth Revival” project at Harvard University.
However, in the wake of the news, many other commentators have read into the claims and they think that the reports of the mammoth’s imminent revival is fake news.
The woolly mammoth were closely related to today’s Indian elephants. They were covered in a thick coat of brown hair to keep them warm in their home of the frigid Arctic plains. They even had fur-lined ears, with curved tusks used for fighting and digging in order to survive. They were extinct almost 10,000 years ago, however some of the bodies have been preserved almost intact. They were around 13 ft tall and weighed approximately 6 tons.
As many mammoth corpses are so well preserved scientists have been able to extract DNA from the animals. The DNA could be used to clone woolly mammoths, bringing them back from extinction. Some objections are that the mammoth’s habitat isn't what it was when the creature roamed the Earth, so where would it live? George Church have used a gene-editing technique to insert the genes from the mammoth into the DNA of elephant skin cells. This is far from cloning , however, but it is a first step to manipulating the DNA found in mammoth corpses.
The woolly mammoth would not be the first species to be revived after being extinct. The world’s first de-extinct animal was born in 2003 in a laboratory in Spain. It was a type of wild mountain goat called a bucardo. Although the animal only lived for only a few minutes, the progress shown was exciting for scientists.
The world is warming, habitats are being lost, places are becoming more polluted and the biodiversity crisis is deepening. For all its worth, de-extinction is worthy of our attention because of the potential it has to help repair ailing ecosystems.
The recent press conference by NASA regarding the discovery of an extraordinary find within our own galaxy. This discovery is known as Trappists-1 or the ultra-cool dwarf star that is located 39.5 years from the sun in the constellation Aquarius.
As of February 2017, this star system shows to hold 7 terrestrial planets, larger than that previously recorded. Astronomers first discovered three Earth sized planets around the dwarf star in 2015, by using the Transiting Planets and planetesimals small telescope (Trappist-1). By using the NASA’s spitzer space telescope and among others, astronomers were able to discover another 4 planets orbiting the star system. From these 7 planters, 3 planets are said to be within the habitable zone of its solar system and may be capable of holding liquid water.
The planets have around the same masas as Earth and Venus.
Getting to Trappist-1
The distance from us to Trappist-1 is 369 Trillion Kilometers. Taking 39 years to get there if we were travelling at the speed of light. It would take Voyager-1, the most distant spacecraft sent by humans, that has left the solar system, 625,000 years to get there .
NASA’s space shuttle, that has a maximum speed of 28000 km/h would take 1.5 million years to reach the star system.
An ultrafast spacecraft that could reach TRAPPIST-1 in a much shorter time span is an interstellar space craft designed by Stephen Hawking.
Hawking's tiny, laser-propelled probes could theoretically fly as fast as 20 percent of the speed of light, or 134 million mph (216 million km/h). That's about 4,000 times faster than NASA's record-breaking New Horizons spacecraft! A spacecraft that fast could travel 39 light-years in less than 200 years. However this is still only a concept and has not been created yet.
With today’s technology, it is impossible for us to get to the Trappist-1 system within a life span. NASA predicts that it will take at least 800,000 years before mankind reaches for Trappist-1. However the discovery of the planet opens up doors that we have never seen, what else does the universe hold that we cannot see. One thing many can say is that this universe is not just ours, there is excitement that Trump could be preparing to launch another manned mission to the Moon. The art of space exploration has ironically slowed as our technology has advanced.
Beijing is currently under an epidemic, with an outbreak of H7N9 “bird flu”. As of the 18th of February, health officials have stated that eight deaths and 77 diagnosed cases in this month alone. The emergence of this viral disease has alarmed many, with officials claiming it to be one of the largest pandemic threats in the last 100 years. The toll of a modern pandemic could result in a very large toll unless the threat is isolated and reacted. Society is much denser than it was before, and despite the advances in technology and health, a repeat of the Spanish flu fears many. The Spanish flu was a deadly pandemic that began in the year 1918, and infected roughly 500 million people across the world, and caused the death of around 50 million at the lowest. Which at the time was around 3% of the world’s population. It was one of the deadliest natural disasters in human history.
Behind the virus, the strain, H7N9 is an avian influenza virus, that has the potency to infect people who come into close contact with newly killed birds, or infected birds. The China’s National Health and Family Planning Commission banned sales of live poultry in most areas across eastern,southern and southwestern China. The eastern province of Zhejiang demanded all live-poultry markets to be closed. Scientists are very concerned that the virus could eventually mutate into one that passes between people, at the moment, almost all confirmed infections have come from direct contact with birds.
H7N9 has a history, in China, reported to have spread in 2013. Many cases spiked each winter and spring, however this year’s spike was the deadliest in four years. In 2003, the outbreak of severe acute respiratory syndrome or SARS, caused many officials to hide the epidemic from the public. This lead to a public distrust that has been created due to the 336 people that died in China from the outbreak. At the moment many experts have claimed that the number of H7N9 cases will only increase, as it is too late to contain the virus in the poultry. WHO, has stated that the biggest risk is the disease spreading outside of the borders of China.
Scientists at the College of Veterinary Medicine, Northwest A&F University in Shaanxi, China were determined to figure out a solution to one of the biggest problems facing dairy farmers around the world: tuberculosis. The scientists concluded their examinations by creating ‘designer cows’ where they were able to be resistant to this infectious disease by simply editing their genes through newly-developed technology called CRISPR, whereby allows scientists globally with access to this software to edit genes to suit the needs to accomplish different objectives (resistance to infectious diseases etc.). This advancement spares farmers from having to kill their cattle to alleviate the spread of the tuberculosis infection to the other animals on site that contribute to the dairy industry in the farm. According to the researchers, the gene led to no adverse effects on the animal, but it did greatly increase TB resistance.
Crispr technology precisely changes target parts of genetic code. Unlike other gene-silencing tools, the Crispr system targets the genome's source material and permanently turns off genes at the DNA level. The DNA cut (known as a double strand break) closely mimics the kinds of mutations that occur naturally, for instance after chronic sun exposure. But unlike UV rays that can result in genetic alterations, the Crispr system causes a mutation at a precise location in the genome. When cellular machinery repairs the DNA break, it removes a small snip of DNA. In this way, researchers can precisely turn off specific genes in the genome.
To carry out the process, the healthy gene used to create a resistance against tuberculosis was inserted into the nucleus of another kind of bovine cell (a fibroblast), taken from a cow foetus. This edited nucleus was then transferred to the egg cell of a cow. The eggs were nurtured in the laboratory, and then fertilised in the lab to form embryos. These were then inserted into the cow and developed and were born as normal. A total of 11 calves with new genes inserted using CRISPR were assessed for resistance to tuberculosis and any adverse genetic effects. From this experiment, it ensured that 11 calves would be able to develop without having the risk to carry or infect other cows which may disturb the farm’s procedures in producing the amount set by external demands - from this advancement, it would also open up many opportunities for other farmers worldwide to use this sort of technology to save money on treatment for their cattle and to produce products more efficiently in the long run.
Scientists are appealing for more people to donate their brains for research, after they have died. This is due to the fact that they are lacking the brains of people with disorders such as post-traumatic stress disorder and depression. The shortage of brains results from a lack of awareness that such conditions are due to changes in brain wiring, hence why the scientists are in need of more brains for research and study.
More than 3000 brains are stored at the Harvard Brain Tissue Resource Centre, just outside Boston, making it one of the largest brain banks in the world. The researchers aim to develop new treatments for mental and neurological disorders such as depression, Parkinson’s Disease and Alzheimer's Disease.
The human brain is a very complex organ, which dictates the way we control our body and ultimately the way we live. Its wirings change and grow as we do. In recent years, researchers have made links between the shape of the brain and mental/neurological disorders. Most if the specimen brains used in research are from people with mental or neurological disorders.
However there is a problem. Scientists do not have enough specimens for the research community. New treatments for mental and neurological diseases are within the grasp of the research community, however the lack of brain tissue if halting the development. Once you die, you can get family consent for organs to be donated for research or transplant. Generally, many people object this due to the body having to be cut open, disturbing the soul of the human. Whilst there is a lack of brains that are being donated, there are many athletes that are donating their brains for research. This will allow scientists to advance in research into chronic traumatic encephalopathy (CTP) - a neurodegenerative disease that has been associated with head injuries. Frank Gifford and Ken Stabler were diagnosed with CTE after their deaths. Many neurodegenerative diseases have been troubling top scientists into finding a cure.
With the possibility of the biomedical world to make conclusions about these diseases and disorders, it would seem logical to donate your brain and other organs to help make a stop to somebody else from suffering and possibly save their life.
Barium is a chemical element found in the periodic table which has an atomic number of 56. It is found in group 2 of the periodic table and hence it is an alkaline metal. Barium is most commonly used in Hospitals under Radiology. Radiology is the study of X-rays and Ultrasounds. A radiographer or a radiologist is a person who specialises in dealing in this field of medicine. Hospitals use Barium in the form of liquid to conducts X-rays on the esophagus and the stomach to view soft tissues.
What are X-rays
An X-ray is part of an electromagnetic spectrum. It is a fast and painless procedure that takes various images of your body. It will only capture hard bones that are found in the body. X-rays are passed through the body anything that is dense; Bone it will be absorbed, and it will show as a white area on the image. However it will become much more difficult to visualise soft tissues on an X-ray. This is where Barium is used.
Barium swallows are a white coloured liquid form of Barium that is taken by patients before having an x-ray of the Esophagus or the stomach. Barium swallow will also contain small amounts of Barium Sulphate this will align the edges of the esophagus and the stomach, X-rays can’t pass through Barium as it is Dense. So it will show up as white on the image and radiographers can then be able to see the stomach and Esophagus.
Barium can also be used for Barium Meals, this is also used in Radiology. This is when again Barium is used in a liquid form to look for any problems that could be found in the stomach. The patient then sits down to allows the liquid to cover the whole of the digestive system. After taking the Barium you also take some Citric acid and and bicarbonate soda. The gases produced will help open the esophagus and the stomach much larger. This allows the radiologist to clearly see the insides.
The benefits to Radiologists of using barium meals and swallows outweighs all the risks from using Barium Swallow. Hence why Barium plays an important role in hospitals
People don’t know what happens when they eat overcooked and burnt foods. As result eating burnt food can lead to the intake of chemicals that can then eventually lead to cancer. Scientists and experts say that bread, chips and many other food should be cooked brown instead of them being burnt. It has been listed by FSA that this is classified as a ‘DANGER FOODS’
Breads, chips and other carbohydrates will contain starch. When this is cooked, fried or heated to high temperatures will produce Acrylamide. Its chemical name is known as: Prop-2-enamide which has a formula of C₃H₅NO. The main uses of Acrylamide is to make: paper, dyes and plastics. The buildings blocks or monomers of Acrylamide is Asparagine. During the heating of food a Maillard reaction takes place. A maillard reaction is when an amino acid and reducing sugars react together which gives food a brow colour and its taste. Alongside this reaction acrylamide can also be formed. Once this chemical is consumed it can enter the body and interact with the DNA causing harmful mutations which can lead to tumours. It is known to be a carcinogen. Acrylamide can also be used a neurotoxin in the body. Neurotoxins are toxins that can cause complete or partial destruction to nerve tissues.
However in some cases when digested acrylamide there is a P450 enzyme that can detoxify it by removing the toxic substances. Research and experiments have been conducted in laboratories on animals and humans to show the effects of acrylamide. However the effects in humans is still not clear and fully understood as of yet.For this reason food experts have set aside some tips of how to reduce the intake of acrylamide.
GO for gold - When frying, cooking or toasting food always cook them to a yellow or golden colour. This is when the production of acrylamide is less. Try and have a balanced and a healthier diet.
Always follow the cooking instructions on the packaging - There will also be advice on how to properly cook the meals to ensure that it prevents the formation of acrylamide.
Finally, never store potatoes in the fridge - Storing Potatoes in the fridges increases the sugar content by forming more sugars - Cold Sweetening. As a result when cooking it more acrylamide can be formed.
So next time when preparing foods you can understand why it is important to process them properly and not cause any problems like this.
The lung has and will always remain one of the most important organs in the human body. Lungs play a crucial role in allowing the body to let in oxygen and let out carbon dioxide. How would a human function without their lungs? Melissa Benoit, a 32 year old from Canada, was dying from a severe lung infection, that initiated organ failure and had an effect on the digestive system. The lung infection was a result of a super-bacteria, that was resistant to most antibiotics, and was able to spread the disease (cystic fibrosis), throughout her body. In what is the world’s first procedure, doctors removed her lungs entirely. Despite being so close to death, Melissa managed to survive due to a transplant that was made in time, however what is most astonishing, is that for 6 days, she survived without lungs. During this time she was placed on an incredibly sophisticated life support machine, which helped her heart pump blood. Two devices were connected to her heart, oxygenating her blood and removing carbon dioxide, whilst another device helped circulate the oxygen-rich blood throughout her body.
The trachea is the main airway from the nose down into the chest, it is a wide tube supported by incomplete rings of strong,and flexible c-shaped cartilage, which stop the trachea from collapsing. Within these trachea, and its branches, are lines of ciliated epithelium, with goblet cells between and below the epithelial cells. The goblet cell secrete mucus onto the lining of the trachea, to trap dust and microorganisms that have escaped the nose lining. The cilia beat and move the mucus away from the lungs, moving away trapped dirt and microorganisms. When cigarettes are smoked, than the cilia stops beating, causes the “smokers cough”. The trachea divides to form the left bronchi, which leads to the left lung, and the right bronchus that leads to the right lung. They are smaller structures of the trachea. The bronchioles divide to form many small bronchioles, which have no cartilage rings, and are of a diameter 1mm or less. The walls of the bronchioles are of smooth muscle, when this muscle contracts, the bronchioles close up. When the smooth muscle relaxes, the bronchioles dilate. This alters the amount of air that reach the lungs. Bronchioles are lined with a thin layer of flattened epithelium, which allows for gas exchange.
The alveoli carry out the most important aspects of gas exchange, the alveoli are tiny air sacs and are unique to mammalian lungs. They are extremely small and consist of a layer thin, flattened epithelial cells, along with some collagen and elastic fibres (elastin). These elastic tissues allow the alveoli to stretch as air is drawn in, and they help squeeze air out when they return to their resting size. This is the function of elastic recoil. The alveoli are efficient for gaseous exchange due to their large surface area, thin layers, good supply of blood; to maintain a steep concentration gradient. Along with good ventilation, through steep diffusion gradients for oxygen and carbon dioxide between the blood and the air in the lungs. The inner surface of the alveoli contain a lung surfactant, which allows for the alveoli to remain inflated.
Air is moved in and out of the lungs, by pressure changes in the chest cavity. The diaphragm is a broad and domed sheet of muscle that forms the floor of the thorax. When you take air in, energy is used, as the diaphragm contracts, and flattens. The external intercostal muscles contract, and move the ribs upwards and outwards, the volume of the thorax increases, and the pressure in the thorax is reduced. Air is drawn in through the nasal passage. When air is exhaled, the muscles relax due to it being a passive process. The diaphragm relaxes, and the external intercostal muscles relax so the ribs move down and inwards under gravity. The elastic fibres in the alveoli of the lung return to their normal length. This process decreases the volume of the thorax.
The lungs play a role, and a role that is incredibly complex and requires multiple processes to be carried out alongside, in order to maintain pressure. Lungs are taken for granted, not many realise what an important role it has in doing something as simple (to us) as breathing.
30 years ago, the world witnessed one of the most catastrophic nuclear accidents in history, causing death to 31 people and leaving hundreds of thousands displaced and homeless. 26th April 1986 after a safety test/experiment the reactors began to meltdown and lead to an explosion releasing radiation into the atmosphere. The disaster happened at Chernobyl Nuclear Power Plant, Pripyat Ukraine. To this date, there has been an exclusion zone of roughly 2600km squared in and around the power plant, with the land being completely unoccupied. This area once housed 120,000 people. The area is considered as too contaminated for residential and agricultural use. However, recently, the Ukrainian government wants to turn part of the exclusion zone into a solar farm. By 2005 deaths tallied up to 4,000 from the effects of radiation and cancer.
Could the world’s worst nuclear accident get a new lease of life?
Apart from a handful of radiation hot-spots, the exclusion zone has become safe to visit, as long as you’re staying for a short period of time. With the successful installation of the new sarcophagus, which will seal the damaged reactor for 100 years, the disaster site is about to see renewed activity.
A large field of 25 acres, which will be filled with solar panels, would generate 5MW. This solar farm would generate a huge amount of power. Along with the existing high-voltage infrastructure, there is an existing population trained in power plant operation.
Solar panels generate electricity from the Sun’s protons, storing electrons within a top layer of silicon that then flow to another silicon layer on the bottom. This generates an electric current. There are over 40 different types of solar panel technology available. With Chernobyl lying on the same latitude as Southern England, this offers excellent solar power generation. Furthermore China have been encouraging people to use damaged and contaminated areas for solar power and wind power farms to generate electricity.
Meanwhile this is just a plan for building solar panels in Chernobyl. Further discussion and talks by the government are deciding to reuse this abandoned space of land to generate more electricity, the magnitude of the project is large and so financially a lot of preparations need to be made. The dome proposal is set to cost £1.5 billion, and will last for 100 years, another excessive amount will be needed to build the solar panel. There is still dangerous amounts of radiation in Chernobyl, that will still take many years to go away.
According to the British Heart Foundation, most of the 600,000 people in the UK are completely unaware of the faulty heart gene they carry- and can pass on to their children. The number turned out to be 100,000 more than the previous estimate. Inherited heart conditions lead to heart failure, and even sudden death from cardiac arrest, if left undetected and untreated.
James Taylor, a former England and Nottinghamshire cricketer, retired last April in 2016 after a near death experience following a warm up session for a game in Cambridge. His heart rate rocketed up to 265 beats per minute and remained there for six to seven hours. The average heart rate for an adult is 60-100 beats per minute; for athletes, it is around 40-60 bpm. Taylor stated that his resting heart rate is around 50 bpm, meaning it shot up to more than 5 times than usual. After scans in a hospital, it was revealed that Taylor had arrhythmogenic right ventricular cardiomyopathy (ARVC) which is an inherited condition caused by a mutation in the genes.
ARVC is a progressive condition where the ventricles of the heart become thin and stretched because the heart muscles are replaced by fat and fibrous tissue. Since the ventricles are responsible for pumping blood to the rest of the body, they cannot distribute blood properly and efficiently when affected by this condition. This greatly increases the chances of cardiac arrest (when the heart stops pumping blood) and sudden death. Every week, 12 people who are 35 years old or under die unexpectedly from inherited heart conditions.
The faulty heart gene is inherited from your parents, which also means that you can pass it on to your children. Some people, called carriers, have the gene but do not express any of the symptoms, but can still pass it on. The gene is still present in their nucleus and when their cells divide meiotically, it will still be present in the gametes produced. Therefore, there is a 50:50 chance the child will acquire it, if one of the parents is a carrier. Signs of a genetic heart disorder can be seen in the family history. Some can include unexplained death at a young age, heart failure at a young age, fainting, blackouts and seizures that could not be treated with typical seizure medication, and if more than one relative has the same heart disease. This discovery will help scientists in allowing to identify how this gene can be eradicated, and reduce chances of it being inherited.