Methods Used in the Bio-Medical Industry

Methods Used in the Bio-Medical Industry In this essay we will be exploring three methods by which materials are either separated, analysed, or both and their relevance and application in the biomedical industry. We will be looking at Electrophoresis, Nuclear Magnetic Resonance (NMR), and Gas Liquid Chromatography-Mass Spectrometry (GLC-MS). Electrophoresis is a technique used to separate DNA material based on their size which has applications in DNA forensics. Nuclear Magnetic Resonance is a technique used to visually determine what the composition of a live tissue is which has applications in medical science. Gas Liquid Chromatography-Mass Spectrometry is a technique used to determine the chemical composition of the substance that is being tested which has applications in blood doping in sports where the blood needs to be chemically analysed for its composition whether it contains banned substances. Chemistry is a very broad subject which has influence in almost every industry. This essay will attempt to cover these three methods knowing that it has only skimmed the surface. The first separation technique that we will discuss is electrophoresis. Electrophoresis is used extensively in biochemical analysis. In particular, it is used in DNA fingerprinting and profiling in the field of forensic science. It can be used to separate, identify and purify proteins and nucleic acids. It can be used with amino acids and peptides obtained when a protein is hydrolysed. This basis for how this method works is that it depends on the fact that all DNA molecules are polar. Thus it is known to be impossible for there to have a compound with the same polarities. Another issue that might be raised is would the mass of the sample affect this separation technique? The answer is yes and no. It will affect it by making the DNA fingerprinting band hard to form. Thus chemists have developed different agarose medium gels for different compounds that have different properties such as pH and mass. The agarose gel can differ in density and pH, for example, to accommodate the differen t types of sample that is being tested. In that way, the effect that mass or even pH might on the result is negated and an accurate result is produced. The DNA of each person is basically similar in its chemical structure. The two strands in the double helix of DNA are held in place via hydrogen bonds between base pairs. The DNA stores the information – call the genes – that provide the genetic blueprints for making proteins. However, there are segments along the DNA molecules which do not seem to carry the instructions needed to make proteins. These bits of DNA are repeated along the DNA molecule. They are called ‘minisatellites’. The number and sequence of these is unique to each person. DNA fingerprinting is based on matching these minisatellite regions of DNA. We inherit half from our mother and the other half from our father. How does it work? Firstly, DNA would be extracted from a sample such as a murder weapon. Next, Restriction enzymes are used to ‘cut’ the DNA molecule at specific places where the same sequences occurs, making smaller fragments for analysis. Because DNA fragments are all negatively charged because of the phosphate groups present them will all move towards the positive electrode in gel electrophoresis. When they move towards the positive electrode in gel electrophoresis, the fragments move at different rates because they have different sizes. And this creates bands. The bands are then made visible by radioactive labelling of the bands with the phosphorus-32 isotope, which causes photographic film to fog. Thus the result is a film that can reveal the positions of the bands and by inference, the identity of the person whose DNA is being tested upon. The analytical technique of electrophoresis is based on separating ions placed in an electric field. If a sample is placed between two electrodes, positively charged ions will move towards a negatively charged electrode. Negatively charged ions will move towards a positively charged electrode. The sample is placed on absorbent paper or on a gel supported on a solid base such as a glass plate. A buffer solution carries the ions along. A buffer solution or medium is used in this method. This is to not only provide a means for the electricity to separate the ions but also as a means to stabilize the pH level because it will affect the movement of ions during electrophoresis. The rate at which the ions move towards the oppositely charged electrode depends, amongst other things, on the size and charge on the ions: larger ions will move more slowly; highly charged ions will move more quickly. Therefore the ions are separated as the electric field is applied. A series of lines or bands on the paper or gel appears once a chemical is applied. Sometimes ultraviolet light is used to show the bands up. The series of bands is called an electropherogram. The bands form a sort of fingerprint as every DNA will show up a different series of bands. In the same way that a thumbprint is uniqu e to a person, these bands made by DNA is unique to every person. A particular limitation is that this experiment does require electricity, an agarose gel medium, a container to store the gel, and it requires a lab free from impurities as it has a high intolerance for contaminants. This may limit the reach of DNA fingerprinting in rural areas or places in third-world countries where access to a biologically clean lab may be difficult. The transport equation for electrophoresis is . C would represent the concentration of the substance undergoing electrophoresis and t wold represent the transport after progressing for a time. This equation explains how time actually affects the concentration of the substance. (Jordan and Mills, 1966) The next technique that we will look at is an analytical technique called the nuclear magnetic resonance (NMR). NMR is mainly used to diagnose medical problems. The technique of MRI (Magnetic Resonance Imaging) scanning has been adapted from NMR spectroscopy. The patient is placed inside a body scanner which generates a powerful magnetic field. A computer analyses the radiowaves absorbed by 1H nuclei in successive ‘slices’ of the body, combining these to make a 3-D image of organs inside the body. The reason that a 3D picture of an organ can be produced just by flipping protons in different magnetic environments can be explained as such. By flipping the protons, a magnetic wave is produced. This wave contains energy that can be measured. When scanning the body, the strength and pattern of this wave is hugely affected by the type, density, and weight of the body that is being measured. Different parts of the body will give off a different wave because not all parts of the body are the same. Some parts of the body contain more muscle or bone than other parts. Thus after scanning the body, data is collected from scanning the different parts of the body that yield different results. Computer imaging software then processes the data that has been collected by the MRI machine and produces a 3D image based on the type of data that it receives. In this way NMR can be explained as such. MRI is much safer than high-energy X-ray imaging. As an example of its use, MRI can monitor the success of cancer treatment in reducing the size of tumours. Nuclear magnetic resonance (NMR) spectroscopy is a widely used analytical technique for organic compounds. NMR is based on the fact that the nucleus of each hydrogen atom in an organic molecule behaves like a tiny magnet. The nucleus of a hydrogen atom consists of a single proton. The proton can spin. This movement of the positively charged proton causes a very small magnetic field to be set up. In NMR the sample is goes to be analysed in a magnetic field. The hydrogen nuclei (protons) either line up with the field or, by spinning in the opposite direction, line up against it. There is a tiny difference in energy between the oppositely spinning 1H nuclei. This difference corresponds to the energy carried by waves in the radiowave range of the electromagnetic radiation spectrum. In NMR spectroscopy the nuclei ‘flip’ between the two energy levels. Only atoms whose mass number is an odd number, e.g. 1H or 13C, absorb energy in the range of frequencies that are analysed. The size of the gap between the nuclear energy levels varies slightly, depending on the other atoms in the molecule (the molecular environment). Therefore, NMR can be used to identify 1H atoms in different parts of a molecule. In NMR spectroscopy, we vary the magnetic field as that is easier than varying the wavelength of radiowaves. As the magnetic field is varied, the 1H nuclei in different molecular environments flip at different field strengths. The different field strengths are measured relative to a reference compound which is given a value of zero. The standard compound chosen is tetramethylsilane (TMS). TMS was chosen because it is an inert, volatile liquid which mixes well with most organic compounds. Its formula is Si (CH3)4, so all its H atoms are equivalent (i.e. they are all in the same molecular environment). TMS only gives one, sharp absorption, called a peak, and this peak is at a higher frequency than most other protons. All other absorptions are measured by their sh ift away from the TMS line on the NMR spectrum. This is called the chemical shift (ÃŽ ´), and is measured in units of parts per million (ppm). The spins within the MRI possess a natural frequency that is proportional to the magnetic field. This is called the Larmor relationship equation. This equation explains the method behind the MRI. Larmor relationship equation ω = ÃŽ ³B Some limitations that can be inferred from data would be that portability, the need for a large amount of electricity, the exclusion of people with tattoos that has ink mixed with metal, people with pacemakers, morbidly obese people, or people who are claustrophobic. Lastly we will look at a separation and analytical technique called the gas-liquid chromatography/mass spectrometer technique. To identify the components in a mixture, it is possible to link a gas-liquid chromatography (GLC) apparatus directly to a mass spectrometer. This combined technique is very sensitive, and any two solutes that can be separated with a time gap of 1 second on a GLC column can be identified almost instantly by the mass spectrometer without the need to be collected. Identification is by comparing the mass spectrum of each solute with the mass spectra of known compounds, using a computer’s spectral database. The generated is complex. There can be many components in a mixture, each with a peak at its particular retention time on the chromatogram, and each peak will generate its own characteristic series of lines in the mass spectrometer. It is possible to combine the chromatogram and the mass spectra to display the data on a 3-D graph. GLC linked to a mass spectrometer is used for analysing complex mixtures. The combined technique is fast and gives reliable results that can identify trace quantities of pollutants, drugs, biochemical molecules and toxins. This means it is used in: forensics, environmental monitoring of pollutants, drug testing in sports, geological and archaeological dating, or even airport security. Gas-liquid chromatography, referred to as GLC, uses partitioning to separate and identify the components in a mixture. How does it work? First, an inert carrier gas such as nitrogen passes in the gas chromatograph to flush the mixture of vapours through the instrument. The mixture to be separated is injected into the instrument through a self-sealing rubber port. Next, an oven heats the injector to vaporise the contents of the mixture, to turn the mixture into a gas if it is not a gas yet. The sample passes through a snail like column oven. After which, the column oven keeps the mixture inside the column in the gaseous state and at a constant temperature. Within the long and thin column there will be a stationary phase, which is often a non-volatile liquid coated onto a solid support. Next, the components of the mixture interact with the stationary phase to different extents, so they move through the column at different rates. Then it passes the sample on to the mass spectrometer to be identified through a tube that is kept at a warm temperature. The stationary phase is an inert carrier gas. This is packed tightly into a column. This has to be forced under pressure through the densely packed column where separation occurs. The tiny solid particles in the column have a very large surface area over which partitioning can occur, resulting in excellent separation. The more polar components in the mixture have a greater relative solubility in the polar solvent. Therefore they are carried through the column faster than components whose molecules are more non-polar (which dissolves better in the non-polar stationary phase in the column). The detector records retention times, i.e. how long it takes each component to pass through the column. The area under each peak recorded is proportional to the amount of solute emerging from the column. For quantitative analysis, the component peaks are first identified and then the area of each is measured. The peaks are roughly triangular in shape so their area follows the area formula. Area is The sample would now go into the mass spectrometer where it will analyse the components of the mixture as they emerge from the column. In the mass spectrometer’s results you can determine the relative proportions of the components of the mixture (from the relative areas of the peaks obtained from the recorded current flow) and the identity of each substance (by matching their mass spectra against a computer database of know spectra (fingerprinting). How does the mass spectrometer separate and identify the gas? First, The vacuum pump first removes unwanted previous sample and air which could interact with the sample by either colliding or reacting with the sample which would contaminate the sample and interfere with the final result. The sample then enters through the sample inlet to proceed to the inside of the mass spectrometer. Next, the sample would enter the vaporisation chamber where a heating coil in the vaporisation chamber converts the sample to a gas if it had not been a gas already. Following that, the sample would proceed into the ionisation chamber where an electron gun bombards electrons at the gaseous sample converting them to positive ions. The equation for this is . The sample at this stage would be go to the accelerator which contains negatively charged electric plates where it accelerates the ions towards the magnetic field. The gaseous ions when approaching the magnetic field would be separated according to t heir mass to charge ratio (). The lighter ions are deflected more, and the heavier ions are deflected less. At the end of the sample’s route is an ion detector where the signal is converted to an electric one. The electric signal is sent to a recorder that interprets this data and plots a graph for analysis because the ions hit the recorder in different positions according to their mass to charge ratio. Lastly, the position where the ions hit the detector plate tells you their relative atomic mass. A practical application for a gas-liquid chromatography/mass spectrometer is in the analysis of urine samples from athletes for banned substances such as steroids or stimulants or even in medical research to separate peptides and proteins. Some advantages of using this method in separating and analysing the sample is that it is possible to determine the percentages of dissolved oxygen, nitrogen, carbon dioxide and carbon monoxide in blood samples as small as 1.0 cm3. Some of the disadvantages are that similar compounds will have similar retention times and if a newly discovered compound is detected it will not have a match in the computer’s database of retention points. As a conclusion, electrophoresis, nuclear magnetic resonance (NMR), and gas-liquid chromatography/mass spectrometer are techniques that affect everyday life. Electrophoresis has a useful function in helping to match the DNA from a crime scene to the criminal in cases where more evidence were need to convict the right person. The nuclear magnetic resonance machines have a the ability to form a 3D image of your inner body and that is useful in the case where detailed analysis of patients in a hospital is important. Other techniques for analysis are mostly either too invasive or too slow. Last but not least is the gas-liquid chromatography/mass spectrometer whose function is to separate compounds to analyse the composition. 1

After a Decade of Global War on Terror Essay

The exodus of Russians from Afghanistan, the megalomania of Iraq’s Saddam, the spread of Islam in the West, the domestic and external pressure on the American economy, the 9/11 historical event, and the voluminous studies of latter-day Dr Strangelove’s clones nurtured and financed by massively-funded American think tanks were all contributing factors in a series of initiatives undertaken by Washington that came to be known as the Global War On Terror. The rise of neo-Christian fundamentalists to counter the upsurge in militant Islamic forces gave strong support to the hype created by President Bush advisors and analysts that Saddam possessed weapons of mass destruction and enabled him to put in motion the grand plan to globally spread American influence. Pakistan got caught in this tornado for some understandable reasons. The only Islamic nation possessing the bomb, bordering Afghanistan, controlling supply lines to Kabul, with ethnic and religious camaraderie transcending the border, largely dependant on Washington-controlled financing agencies, with a ballooning population under 25 years old that may be swayed by extremist elements, and the docility of it’s political and military leadership to United States’ dictation. Thus the loud threat of â€Å"you with us or you against us† worked pronto and Pakistan was touted as the frontline state in GWOT. The decade of this GWOT has made Pakistan front-page news day in and day out. Every week some American high-up or some Congressional delegation comes to Islamabad and, while breathing down the neck of the political and military leadership, proclaims the mantra of â€Å"Do More†. This has put Pakistan in a precarious position and its impact has been widespread all across the country. Over this eventful and volatile decade, Pakistan has faced situations that have fundamentally changed its political, economic, and social landscape. The GWOT enabled the democratic forces to unite against a government controlled by President General Pervez Musharraf and negotiate a new political order thru the notorious National Reconciliation Order. This paved the way for Benazir Bhutto and Nawaz Sharif to end their self-imposed and forced exiles. The assassination of Benazir Bhutto has been blamed on the terrorists and extremists that are the legacy of GWOT. The Liaquat Bagh Rawalpindi tragedy created a wave of sympathy and her party came into power with her tainted husband anointing himself as President. â€Å"Democracy is the best revenge† became the rallying slogan, but political instability, political expediency, and political distrust cast a glooming shadow on all imperative and crucial national decisions. The government hid its weaknesses, its insensitivity, and its in ability to undertake decisions by camouflaging it as outcome of its fulltime concentration and determination to weed out terrorism and extremism. On the social side, the nation has been horrendously affected by the ten years of intense involvement in the GWOT. The most sad and tragic outcome has been the death of over 35,000 citizens and military personnel. Scarce financial resources have been diverted to fighting this war at the cost of neglecting social sectors such as education and health. The track record of various governments has always been pathetic when it came to allocation for social sectors. No government has spent more that 3% of GDP on health and education and the GWOT also encroached on this allocation too. The rehabilitation and rebuilding of war-torn areas put a huge dent in the Treasury. Moreover, biased ethnicity, tribal rivalry, and parochial mindset all gained strength from the after-effects of this war and impacted on the decision making process of the government and the administration. Pakistan has been the worst sufferer in economic terms because of the GWOT. The Finance Ministry has estimated that the nation spent over US$ 68 billion during the past decade in fighting this war. This amount equals the combined 2010-11 import and export figure. In the past couple of years, the government has drastically cut down essential projects under the Pakistan Social Development Program while also arbitrarily raising electricity and gas rates. The GWOT, coupled with the annual floods, have also messed up the GDP rate which is less than 3% with scant chance of it crossing the 3.50% mark in the current fiscal year. Asian Development Bank has estimated an annual 7% growth rate to absorb the burgeoning labor force that is looking for meaningful employment. This is a tall order and there is no window of opportunity on the horizon. Pakistan’s image has been seriously tarnished due to the GWOT. This has put pressure on the development of new export markets and affected the comfort zone that importers of Pakistani products had in dealing with their suppliers. The law and order imbroglio, especially in Karachi, has also been detrimental to the progress of Pakistan’s economy. Notwithstanding the highest-ever exports in 2010-11, the fact is that it was more due to increase in world prices rather than additional increase in quantity. Today, unemployment is a major issue and it naturally induces the unemployed to succumb to the â€Å"sales pitch† of terrorist and extremist organizations. Pakistan’s defence bill is tremendously increasing inspite of the efforts of the military hierarchy not to open new military operation theatres to fight terrorism. Pakistan is not being timely compensated by America for the huge expenses incurred by the defence forces. Moreover, the Kerry-Luger-Bremen Act under which development aid would be forthcoming has also been a victim of the change in Washington’s perception of the Pakistan’s efforts. Even the International Financing Institutions, primarily IMF, also get their signals from Washington. Now, Pakistan is compelled to announce that it is abandoning the IMF program and not applying for a new initiative to tackle its economic requirements. All in all, with a limited financial base, with only about $200 billion GDP, with 185 million people, with tremendous competition in the global export market, with obvious political instability, with rise of extremist Islamic militants, with no signs of cessation of hostilities at the border, and with United States wanting Pakistan to â€Å"Do More†, Pakistan will not be the ultimate beneficiary of the Global War on Terror.

Emotional Quotient And Spiritual Intelligence In The Workplace Essay

As the world progresses and advances towards globalization, the global economy is demanding for the existence of well-managed companies and organizations. Responding to this demand, organizations are trying to find more effective formula that will enhance or improve their outputs. Two of the latest discoveries that attract companies and organizations are the concepts of emotional and spiritual development of their human resources. More and more companies are integrating the said formula in their programs and action plans as they recognize the need of these concepts that were long been neglected. In this paper, we will analyze the arguments of two chosen articles which focus on Emotional Intelligence (Must Have EQ by Anthony Landale) and Spiritual Intelligence (The Practical Application of Spiritual Intelligence in the Workplace by Mike George). Anthony Landale, in his article entitled â€Å"Must Have EQ†, argued that Emotional Intelligence or EQ (Emotional Quotient) the key for an organization to meet the challenge of getting people work together more effectively (Landale, Andrew Feb/March 2007, page 24). In line with this, the author presented his stand in four clear points. First, he argued that EQ is vital in keeping the organization or team members intact. Second, he argued that each team member must be able to learn how to manage our emotions by constantly checking our own individual behaviors. Landale made it clear that behaviors are innate in humans and that every person has his own set of good and bad behaviors. Relative to this, a person who has high emotional intelligence is able to manage even the undesirable behaviors by expressing them in the right place, time and manner. Third, Landale argued that EQ development requires empathy, which is putting oneself in the place of others. This means that one is required to constantly deal with others at work, learn to adjust as needed and be able to adapt with the situation. Lastly, the author stressed that communication is vital in the development of emotional intelligence and of keeping the organization healthy. To be able to do this, every member must maintain an open and honest communication. It was also stressed that a two-way communication line is required which means that feedback to and from management must be kept working. Emotional intelligence is therefore measured according to the person’s skill of managing his or her emotions and behaviors because EQ is actually â€Å"Self-Management. † In partnership with EQ, a company must also train its human resources to develop Spiritual Intelligence (SQ). The author centered his arguments on the practical applications of SQ especially in the workplace because SQ development focuses on the three deepest motivations of humans: creativity, meaning and purpose (George, Mike 2006, page 3). The author argued that since Spiritual Intelligence directly work with these three human motivations, SQ development will definitely make a company a vibrant workplace. If a person’s SQ is well-developed, he will be able to have a clear sense of his identity and a definite purpose. Spiritual intelligence enables a person to live with integrity by setting a good example. Because SQ gives the individual the power the flexibility to adapt to the environment, a person with high SQ is able to be cool and focused even in a stressful situation. By developing one’s self-awareness, a person with high SQ also will have the power to find the cause of his emotions, its meanings and be able to manage them. This in turn will develop one’s empathy. Spiritual intelligence focuses on the development on a person’s ability to fight the ego in order for him to adapt to changes. Finally, development of spiritual intelligence enables a person to recognize the non-material reality of his being that is humans have non-material needs which when recognized alleviates life’s insecurity. If cognitive intelligence is about thinking and emotional intelligence is about feeling, then spiritual intelligence is about being† (McMullen, Brian 2003). In line with the arguments of Landale and George, this statement is parallel with their point of view that EQ has something to do with self-management while SQ deals with self-awareness of the non-material reality of the being. In the modern world, people are inclined to boosting their cognitive intelligence (IQ) as this may seem the measuring device for one’s success in life. But the real working world does not acknowledge the importance of IQ alone, rather the development of all four basic intelligences that define the successful individual. â€Å"IQ appears to be related to minimum standards to enter a given a profession† (Wiggleswoth, Cindy ). In line with Landale’s claim that EQ is of managing emotions, a study of store managers in retail chain proved that efficient management of emotions especially with stress is important for success (Cherniss, Cary 2000). However Cherniss stressed that this is just one aspect of the complex scope of emotional intelligence. He said that â€Å"emotional intelligence has as much to do with knowing when and how to express emotion as it do with controlling it. † This statement corroborates Landale’s idea that EQ is of acknowledging and identifying the emotions and learning how to express them in a proper behavior (Landale, Andrew 2007, page 24). The importance of this aspect of EQ was proven worthwhile in modern organizations as with the experiment done in the US navy wherein researchers found that â€Å"the most effective leaders in the US Navy were warmer, more outgoing, emotionally expressive, dramatic, and sociable† (Barsade, S. t. al 1998). Another aspect of emotional intelligence is empathy which is proven by researchers that it contributes to occupational success (Cherniss, Cary 2000). This is the aspect that overlaps with the concept of spiritual development which also acknowledges the importance of empathy in recognizing the cause of the emotions and be able to utilize them in adapting to changes. â€Å"EQ is the development of the capacity for self-control and the ability to respond with sensitivity and empathy† (Oxford Leadership Academy). This is also important if a manager or someone in the organization would like to positively influence the work behaviors of other members. A practical application of this as cited in one article is that one’s effectiveness can influence others depending on one’s ability to connect with them particularly of understanding the feelings of others (Goleman, Daniel 1999). To effectively influence others we also need to be able to manage our own emotions. Connected to EQ development is the spiritual intelligence which centers on developing the skills of the person in managing the inner self or the non-material reality of one’s being as claimed by George. One author defined spiritual intelligence as â€Å"the ability to behave with Compassion and Wisdom while maintaining inner and outer peace (equanimity) regardless of the circumstances† (Wigglesworth, Cindy). Since compassion encompasses the ability to understand the feelings of others, as what empathy suggests, the concepts of EQ and SQ therefore work together towards the complete success of a person and the organization where he belongs. The practical point of this is that when someone is emotionally and spiritually intelligent, he will be able to make the most out of his skills, emotions, behaviors and traits in managing himself and in turn will give him the power to positively connect with others. That optimism is brought about by the fact that the person, with empathy and compassion, understands the emotions of others which give him the ability to stay calm and focused no matter what the situation brings. Relative to George’s argument that spiritual intelligence in necessary for a person to live a life with integrity and in line with the clear purpose, one author has the same perspective. According to 1Wigglesworth, spiritual intelligence development encompasses self and universal awareness including the ego and social mastery. In the management world, spiritually intelligent manager is a â€Å"wise and effective change agent† who makes compassionate and wise decisions. Wigglesworth further said that SQ enables managers to have the calming and healing presence in the midst of stressful workplace. In contrast with George who did not acknowledge the importance of communication in the development of SQ, Landale stressed that EQ development requires a manager to â€Å"prioritize the giving and receiving of feedbacks† (Landale, Anthony 2007). Connecting with other members of the organization builds and cultivates relationships and that can only be possible when open communication is active in the organization. Putting the essentials of emotional and spiritual intelligence, we clearly draw out the idea that the development of these basic intelligences focus on relationships which is especially important in building an effective, efficient working environment. The human resources of the organization are its most valuable assets so it is vital that that training and development should include the wholeness of their being. Companies of the modern economy is already recognizing the fact the business is not all about making money, rather it encompasses the building of organization members with multiple intelligence. An organization with personnel, especially leaders, who have well developed cognitive, emotional and spiritual intelligence, is a happy and enthusiastic working environment. Developing the emotional and spiritual intelligence is the answer to the intangible needs of the organization: healthy working relationships.

The Events of September 11, 2001

On the morning of September 11, 2001, Islamic extremists organized and trained by the Saudi-based jihadist group al-Qaeda hijacked four American commercial jet airliners and used them as flying bombs to carry out suicide terrorist attacks against the United States. American Airlines Flight 11 crashed into Tower One of the World Trade Center at 8:50 AM. United Airlines Flight 175 crashed into Tower Two of the World Trade Center at 9:04 AM. As the world watched, Tower Two collapsed to the ground at about 10:00 AM. This unimaginable scene was duplicated at 10:30 AM when Tower One fell.   At 9:37 AM, a third plane, American Airlines Flight 77, was flown into the west side of the Pentagon in Arlington County, Virginia. The fourth plane, United Airlines Flight 93, initially being flown toward an unknown target in Washington, D.C., crashed into a field near Shanksville, Pennsylvania at 10:03 AM, as passengers fought with the hijackers. Later confirmed as acting under the leadership of Saudi fugitive Osama bin Laden, the terrorists were believed to be attempting to retaliate for America’s defense of Israel and continued military operations in the Middle East since the 1990 Persian Gulf War.   The 9/11 terrorist attacks resulted in the deaths of nearly 3,000 men, women, and children and the injuries of more than 6,000 others. The attacks triggered major ongoing U.S. combat initiatives against terrorist groups in Iraq and Afghanistan and largely defined the presidency of George W. Bush. America’s Military Response to the 9/11 Terror Attacks No event since the Japanese attack on Pearl Harbor propelled the nation into World War II had the American people been brought together by a shared resolved to defeat a common enemy. At 9 PM on the evening of the attacks, President George W. Bush spoke to the American people from the Oval Office of the White House, declaring, â€Å"Terrorist attacks can shake the foundations of our biggest buildings, but they cannot touch the foundation of America. These acts shatter steel, but they cannot dent the steel of American resolve.† Foreshadowing America’s impending military response, he declared, â€Å"We will make no distinction between the terrorists who committed these acts and those who harbor them.† On October 7, 2001, less than a month after the 9/11 attacks, the United States, supported by a multinational coalition, launched Operation Enduring Freedom in an effort to overthrow the oppressive Taliban regime in Afghanistan and destroy Osama bin Laden and his al-Qaeda terrorist network. By the end of December 2001, U.S and coalition forces had virtually eradicated the Taliban in Afghanistan. However, a new Taliban insurgency in neighboring Pakistan resulted in the continuation of the war. On March 19, 2003, President Bush ordered U.S. troops into Iraq on a mission to overthrow Iraqi dictator Saddam Hussein, believed by the White House to be developing and stockpiling weapons of mass destruction while harboring Al Qaeda terrorists in his county. Following the overthrow and imprisonment of Hussein, President Bush would face criticism after a search by United Nations inspectors found no evidence of weapons of mass destruction in Iraq. Some argued that the Iraq War had unnecessarily diverted resources from the war in Afghanistan. Though Osama bin Laden remained at large for over a decade, the mastermind of the 9/11 terror attack was finally killed while hiding out in an Abbottabad, Pakistan building by an elite team of U.S. Navy Seals on May 2, 2011. With the demise of bin Laden, President Barack Obama announced the beginning of large-scale troop withdrawals from Afghanistan in June 2011. As Trump Takes Over, War Goes On Today, 16 years and three presidential administrations after the 9/11 terror attacks, the war continues. While its official combat role in Afghanistan ended in December 2014, the United States still had nearly 8,500 troops stationed there when President Donald Trump took over as Commander in Chief in January 2017. In August 2017, President Trump authorized the Pentagon to increase the troop levels in Afghanistan by several thousand and announced a change in policy regarding the release of future troop level numbers in the region. â€Å"We will not talk about numbers of troops or our plans for further military activities, Trump said. Conditions on the ground, not arbitrary timetables, will guide our strategy from now on,† he said. â€Å"Americas enemies must never know our plans or believe they can wait us out.† Reports at the time indicated that top US military generals had advised Trump that a â€Å"few thousand† additional troops would help the U.S. make progress in eliminating the insurgent Taliban and other ISIS fighters in Afghanistan. The Pentagon stated at the time that the additional troops would be conducting counterterrorism missions and training Afghanistan’s own military forces.   Updated by Robert Longley