Air pollution

Main articles: Pollutant and Greenhouse gas

Before flue gas desulfurization was installed, the emissions from this power plant in New Mexico contained excessive amounts of sulfur dioxide.

Schematic drawing, causes and effects of air pollution: (1) greenhouse effect, (2) particulate contamination, (3) increased UV radiation, (4) acid rain, (5) increased ozone concentration, (6) increased levels of nitrogen oxides
An air pollutant is known as a substance in the air that can cause harm to humans and the environment. Pollutants can be in the form of solid particles, liquid droplets, or gases. In addition, they may be natural or man-made.[1]
Pollutants can be classified as either primary or secondary. Usually, primary pollutants are substances directly emitted from a process, such as ash from a volcanic eruption, the carbon monoxide gas from a motor vehicle exhaust or sulfur dioxide released from factories.
Secondary pollutants are not emitted directly. Rather, they form in the air when primary pollutants react or interact. An important example of a secondary pollutant is ground level ozone — one of the many secondary pollutants that make up photochemical smog.
Note that some pollutants may be both primary and secondary: that is, they are both emitted directly and formed from other primary pollutants.
About 4 percent of deaths in the United States can be attributed to air pollution, according to the Environmental Science Engineering Program at the Harvard School of Public Health.
Major primary pollutants produced by human activity include:
Sulfur oxides (SOx) - especially sulfur dioxide, a chemical compound with the formula SO2. SO2 is produced by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide. Further oxidation of SO2, usually in the presence of a catalyst such as NO2, forms H2SO4, and thus acid rain.[2] This is one of the causes for concern over the environmental impact of the use of these fuels as power sources.
Nitrogen oxides (NOx) - especially nitrogen dioxide are emitted from high temperature combustion. Can be seen as the brown haze dome above or plume downwind of cities. Nitrogen dioxide is the chemical compound with the formula NO2. It is one of the several nitrogen oxides. This reddish-brown toxic gas has a characteristic sharp, biting odor. NO2 is one of the most prominent air pollutants.
Carbon monoxide - is a colourless, odourless, non-irritating but very poisonous gas. It is a product by incomplete combustion of fuel such as natural gas, coal or wood. Vehicular exhaust is a major source of carbon monoxide.
Carbon dioxide (CO2) - a greenhouse gas emitted from combustion but is also a gas vital to living organisms. It is a natural gas in the atmosphere.
Volatile organic compounds - VOCs are an important outdoor air pollutant. In this field they are often divided into the separate categories of methane (CH4) and non-methane (NMVOCs). Methane is an extremely efficient greenhouse gas which contributes to enhanced global warming. Other hydrocarbon VOCs are also significant greenhouse gases via their role in creating ozone and in prolonging the life of methane in the atmosphere, although the effect varies depending on local air quality. Within the NMVOCs, the aromatic compounds benzene, toluene and xylene are suspected carcinogens and may lead to leukemia through prolonged exposure. 1,3-butadiene is another dangerous compound which is often associated with industrial uses.
Particulate matter - Particulates, alternatively referred to as particulate matter (PM) or fine particles, are tiny particles of solid or liquid suspended in a gas. In contrast, aerosol refers to particles and the gas together. Sources of particulate matter can be man made or natural. Some particulates occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels in vehicles, power plants and various industrial processes also generate significant amounts of aerosols. Averaged over the globe, anthropogenic aerosols—those made by human activities—currently account for about 10 percent of the total amount of aerosols in our atmosphere. Increased levels of fine particles in the air are linked to health hazards such as heart disease[2], altered lung function and lung cancer.
Persistent free radicals connected to airborne fine particles could cause cardiopulmonary disease.[3][4]
Toxic metals, such as lead, cadmium and copper.
Chlorofluorocarbons (CFCs) - harmful to the ozone layer emitted from products currently banned from use.
Ammonia (NH3) - emitted from agricultural processes. Ammonia is a compound with the formula NH3. It is normally encountered as a gas with a characteristic pungent odor. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to foodstuffs and fertilizers. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceuticals. Although in wide use, ammonia is both caustic and hazardous.
Odors — such as from garbage, sewage, and industrial processes
Radioactive pollutants - produced by nuclear explosions, war explosives, and natural processes such as the radioactive decay of radon.
Secondary pollutants include:
Particulate matter formed from gaseous primary pollutants and compounds in photochemical smog. Smog is a kind of air pollution; the word "smog" is a portmanteau of smoke and fog. Classic smog results from large amounts of coal burning in an area caused by a mixture of smoke and sulfur dioxide. Modern smog does not usually come from coal but from vehicular and industrial emissions that are acted on in the atmosphere by sunlight to form secondary pollutants that also combine with the primary emissions to form photochemical smog.
Ground level ozone (O3) formed from NOx and VOCs. Ozone (O3) is a key constituent of the troposphere (it is also an important constituent of certain regions of the stratosphere commonly known as the Ozone layer). Photochemical and chemical reactions involving it drive many of the chemical processes that occur in the atmosphere by day and by night. At abnormally high concentrations brought about by human activities (largely the combustion of fossil fuel), it is a pollutant, and a constituent of smog.
Peroxyacetyl nitrate (PAN) - similarly formed from NOx and VOCs.
Minor air pollutants include:
A large number of minor hazardous air pollutants. Some of these are regulated in USA under the Clean Air Act and in Europe under the Air Framework Directive.
A variety of persistent organic pollutants, which can attach to particulate matter.
Persistent organic pollutants (POPs) are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of this, they have been observed to persist in the environment, to be capable of long-range transport, bioaccumulate in human and animal tissue, biomagnify in food chains, and to have potential significant impacts on human health and the environment.

Mount Sinai Hospital, New York

This article is about the hospital in New York. For the medical school, see Mount Sinai School of Medicine.
Mount Sinai Hospital

Mount Sinai from Central Park
Location
One Gustave L. Levy Place, 1190 Fifth Avenue, New York, New York, United States
Organization
Hospital type
University, Teaching
Affiliated university
Mount Sinai School of Medicine
Beds
1,171
Founded
1852
Website
http://www.mountsinai.org/
Lists
Hospitals in the United States
Mount Sinai Hospital, founded in 1852, is one of the oldest and largest teaching hospitals in the United States. In 2009, Mount Sinai Hospital was ranked as one of the best hospitals in the U.S. by U.S. News & World Report in 11 specialties.[1]
Located on the eastern border of Central Park, at 100th Street and Fifth Avenue, in New York City's Manhattan, Mount Sinai has a number of hospital affiliates in the New York metropolitan area, and an additional campus, the Mount Sinai Hospital of Queens.
The hospital is also affiliated with one of the foremost centers of medical education and biomedical research, Mount Sinai School of Medicine, which opened in September 1968.[2] Together, the two comprise the Mount Sinai Medical Center

Reputation

U.S. News & World Report's "America's Best Hospitals 2009-10" issue ranked Mount Sinai Hospital among its "Honor Roll." Mount Sinai Hospital is ranked #3 in the U.S. for geriatric care and #7 in digestive disorders. Other honors from that issue included high rankings for cancer (#42), ear, nose & throat (#17), gynecology (#28), heart & heart surgery (#18), kidney disorders (#30), neurology & neurosurgery (#16), orthopedics (#21), psychiatry (#21), and rehabilitation (#19).[3]
New York Magazine's inaugural "Best Hospitals" list ranked Mount Sinai Medical Center as #2 for overall best hospital, #3 for emergency care, #3 for pediatrics, #4 for ENT, #3 for psychiatry, #3 for cancer, #3 for cardiac care, #1 for digestive disorders, #5 for orthopedics, #2 for OB-GYN, and #3 for neurology/neurosurgery.[4]
New York Magazine’s annual “Best Doctors” issue lists 224 Mount Sinai faculty and staff, including those who serve at an affiliated institution. Excluding affiliates, the Mount Sinai Medical Center maintained its strong position in the rankings, with 135 physicians listed. Mount Sinai also ranked above peer institutions including New York Presbyterian/Columbia, Presbyterian Hospital/Weill Cornell, and NYU Langone Medical Center.[5]
In 2010, the New York State Department of Health named Mount Sinai Hospital the safest place for a patient receiving angioplasty.[6]
In 2009, The Scientist magazine ranked Mount Sinai School of Medicine 15th overall in their “Best Places to Work in Academia” survey.[7]
In 2009, the American Nurses Credentialing Center (ANCC)'s Magnet Award for Nursing Excellence was awarded to Mount Sinai – the first full-service hospital in New York City to achieve redesignation. Only six percent of hospitals in the nation have received Magnet designation, and only two percent have received redesignation.[8]
In 2008, Mount Sinai Medical Center received the Public & Community Service Emmy Award presented by the National Academy of Television Arts & Sciences (NATAS).[9]
In 2008, Mount Sinai was recognized for improved performance in Thomson Reuters' "100 Top Hospitals" list. The Mount Sinai Medical Center, as a major teaching hospital, was the only hospital in Manhattan, New York to be awarded this high honor.[10]
In 2006, the American Society for Bariatric Surgery named Mount Sinai a "Surgery Center of Excellence."[11]
In 2006, Mount Sinai and its advertising agency, DeVito/Verdi, took home the highest honors at the 23rd Annual Healthcare Advertising Awards. The campaign was awarded top prize in the Large Hospitals Group for three different categories: Magazine, Billboard and Radio.[12]

Boxer's fracture

A boxer's fracture is the common name for a fracture at the neck of the bones which form the knuckles of the hand[1]. The fracture usually occurs at the neck of the fifth metacarpal, which forms the knuckle of the little finger[2], but the same name may also be used for a fracture at the neck of any of the metacarpals. This injury is also known as the brawler's fracture; a fracture of the neck of the fifth or fourth metacarpal can also be called a bar room fracture.[3]

Treatment
These fractures are often angulated, and if severely so require pins to be put in place and realignment as well as the usual splinting. However, the prognosis on these fractures is generally good, with total healing time not exceeding 12 weeks. The first two weeks will show significantly reduced overall swelling with improvement in clenching ability showing up first. Ability to extend the fingers in all directions appears to improve more slowly. Hard casts are rarely required and soft casts or splints can be removed for brief periods of time to allow for activities such as showers and "airing out" the cast or splinted area so as to avoid skin rotting and permit cleansing of the cast or splinted area. Pain from this injury is generally very mild and rarely requires medications beyond over the counter drugs such as ibuprofen or acetaminophen. Muscle atrophy in isolated areas of 5 to 15 percent should be expected with a rehabilitation period of approximately 4 months given adequate therapy. In the mildest of cases, full rehabilitation status can be achieved within 3 to 4 months.
For smaller angled fractures most discomfort is alleviated by raising the fracture above the heart, also if there is no cast warm water will relieve some of the pain. It is important that when the cast is removed that the hand is gently exercised by attempting the common functions of the hand.
Prevention
Boxers and other combat athletes routinely use hand wraps and boxing gloves to help stabilize the hand, greatly reducing pain and risk of injury during impact training such as working the heavy bag. Hand wraps are made with typical athletic tape. Karate and Tae kwon-do practitioners avoid this injury by striking with straight punches using the knuckles of the index and middle fingers. It has been concluded through martial arts training that punching with the tightest possible clenched fist can prevent this type of fracture as well.[citation needed]

Hand surgery

The field of hand surgery deals with both surgical and non-surgical treatment of conditions and problems that may take place in the hand or upper extremity (commonly from the tip of the hand to the shoulder). Hand surgery may be practiced by graduates of general surgery, orthopedic surgery and plastic surgery. Plastic surgeons and orthopedic surgeons receive significant training in hand surgery during their residency training, with some graduates continuing on to do an additional one year hand fellowship. These fellowships are sometimes also pursued by general surgeons. Plastic surgeons are particularly well suited to handle traumatic hand and digit amputations that require a "replant" operation. Orthopedic surgeons are trained to reconstruct all aspects to salvage the appendage: tendons, muscle, bone. Orthopedic surgeons are particularly well suited to handle complex fractures of the hand and injuries to the carpal bones that alter the mechanics of the wrist.
In a few countries such as Sweden, Finland and Singapore, Hand Surgery is recognized as a clinical specialty in its own right with a formal four to six years hand surgery resident training program. Hand surgeons going through these programs are trained in all aspects of hand surgery, combining and mastering all the skills traditionally associated with "Orthopedic hand surgeons" and "Plastic hand surgeons" to become equally adept at handling tendon, ligament and bone injuries as well as microsurgical reconstruction such as reattachment of severed parts or free tissue transfers and transplants.
Hand surgeons perform a wide variety of operations such as fracture repairs, releases, transfer and repairs of tendons and reconstruction of injuries, rheumatoid deformities and congenital defects. They also perform microsurgical reattachment of amputated digits and limbs, microsurgical reconstruction of soft tissues and bone, nerve reconstruction, and surgery to improve function in paralysed upper limbs.

History

Food processing dates back to the prehistoric ages when crude processing incorporated slaughtering, fermenting, sun drying, preserving with salt, and various types of cooking (such as roasting, smoking, steaming, and oven baking). Salt-preservation was especially common for foods that constituted warrior and sailors' diets, up until the introduction of canning methods. Evidence for the existence of these methods exists in the writings of the ancient Greek , Chaldean, Egyptian and Roman civilizations as well as archaeological evidence from Europe, North and South America and Asia. These tried and tested processing techniques remained essentially the same until the advent of the industrial revolution. Examples of ready-meals also exist from pre industrial revolution times such as the Cornish pasty and the Haggis
Modern food processing technology in the 19th and 20th century was largely developed to serve military needs. In 1809 Nicolas Appert invented a vacuum bottling technique that would supply food for French troops, and this contributed to the development of tinning and then canning by Peter Durand in 1810. Although initially expensive and somewhat hazardous due to the lead used in cans, canned goods would later become a staple around the world. Pasteurization, discovered by Louis Pasteur in 1862, was a significant advance in ensuring the micro-biological safety of food.
In the 20th century, World War II, the space race and the rising consumer society in developed countries (including the United States) contributed to the growth of food processing with such advances as spray drying, juice concentrates, freeze drying and the introduction of artificial sweeteners, colouring agents, and preservatives such as sodium benzoate. In the late 20th century products such as dried instant soups, reconstituted fruits and juices, and self cooking meals such as MRE food ration were developed.
In western Europe and North America, the second half of the 20th century witnessed a rise in the pursuit of convenience, food processors especially marketed their products to middle-class working wives and mothers. Frozen foods (often credited to Clarence Birdseye) found their success in sales of juice concentrates and "TV dinners". [1] Processors utilised the perceived value of time to appeal to the postwar population, and this same appeal contributes to the success of convenience foods today

Benefits
Mass production of food is much cheaper overall than individual production of meals from raw ingredients. Therefore, a large profit potential exists for the manufacturers and suppliers of processed food products. Individuals may see a benefit in convenience, but rarely see any direct financial cost benefit in using processed food as compared to home preparation. Poor quality ingredients and sometimes questionable processing and preservation methods detract greatly from the overall benefit gained by individual consumers.
More and more people live in the cities far away from where food is grown and produced. In many families the adults are working away from home and therefore there is little time for the preparation of food based on fresh ingredients. The food industry offers products that fulfill many different needs: From peeled potatoes that only have to be boiled at home to fully prepared ready meals that can be heated up in the microwave oven within a few minutes.
Benefits of food processing include toxin removal, preservation, easing marketing and distribution tasks, and increasing food consistency. In addition, it increases seasonal availability of many foods, enables transportation of delicate perishable foods across long distances, and makes many kinds of foods safe to eat by de-activating spoilage and pathogenic micro-organisms. Modern supermarkets would not be feasible without modern food processing techniques, long voyages would not be possible, and military campaigns would be significantly more difficult and costly to execute.
Modern food processing also improves the quality of life for people with allergies, diabetics, and other people who cannot consume some common food elements. Food processing can also add extra nutrients such as vitamins.
Processed foods are often less susceptible to early spoilage than fresh foods, and are better suited for long distance transportation from the source to the consumer. Fresh materials, such as fresh produce and raw meats, are more likely to harbour pathogenic micro-organisms (e.g. Salmonella) capable of causing serious illnesses

Three-dimensional (3D) image reconstruction

The principle

Because contemporary CT scanners offer isotropic or near isotropic, resolution, display of images does not need to be restricted to the conventional axial images. Instead, it is possible for a software program to build a volume by "stacking" the individual slices one on top of the other. The program may then display the volume in an alternative manner.^[25]

Multiplanar reconstruction

Typical screen layout for diagnostic software, showing one 3D and three MPR views

Multiplanar reconstruction (MPR) is the simplest method of reconstruction. A volume is built by stacking the axial slices. The software then cuts slices through the volume in a different plane (usually orthogonal). Optionally, a special projection method, such as maximum-intensity projection (MIP) or minimum-intensity projection (mIP), can be used to build the reconstructed slices.

MPR is frequently used for examining the spine. Axial images through the spine will only show one vertebral body at a time and cannot reliably show the intervertebral discs. By reformatting the volume, it becomes much easier to visualise the position of one vertebral body in relation to the others.

Modern software allows reconstruction in non-orthogonal (oblique) planes so that the optimal plane can be chosen to display an anatomical structure. This may be particularly useful for visualising the structure of the bronchi as these do not lie orthogonal to the direction of the scan.

For vascular imaging, curved-plane reconstruction can be performed. This allows bends in a vessel to be "straightened" so that the entire length can be visualised on one image, or a short series of images. Once a vessel has been "straightened" in this way, quantitative measurements of length and cross sectional area can be made, so that surgery or interventional treatment can be planned.

MIP reconstructions enhance areas of high radiodensity, and so are useful for angiographic studies. mIP reconstructions tend to enhance air spaces so are useful for assessing lung structure.

3D rendering techniques

Surface rendering

A threshold value of radiodensity is chosen by the operator (e.g. a level that corresponds to bone). A threshold level is set, using edge detection image processing algorithms. From this, a three-dimensional model can be constructed and displayed on screen. Multiple models can be constructed from various different thresholds, allowing different colors to represent each anatomical component such as bone, muscle, and cartilage. However, the interior structure of each element is not visible in this mode of operation.

Volume rendering

Surface rendering is limited in that it will only display surfaces which meet a threshold density, and will only display the surface that is closest to the imaginary viewer. In volume rendering, transparency and colors are used to allow a better representation of the volume to be shown in a single image—e.g. the bones of the pelvis could be displayed as semi-transparent, so that even at an oblique angle, one part of the image does not conceal another.

Image segmentation

Main article: Segmentation (image processing)

Where different structures have similar radiodensity, it can become impossible to separate them simply by adjusting volume rendering parameters. The solution is called segmentation, a manual or automatic procedure that can remove the unwanted structures from the image.

Example

Some slices of a cranial CT scan are shown below. The bones are whiter than the surrounding area. (Whiter means higher attenuation.) Note the blood vessels (arrowed) showing brightly due to the injection of an iodine-based contrast agent.

Computed tomography of human brain, from base of the skull to top. Taken with intravenous contrast medium.

Individual images of CT (click at right to hide or show)[show]

A volume rendering of this volume clearly shows the high density bones.

Bone reconstructed in 3D

After using a segmentation tool to remove the bone, the previously concealed vessels can now be demonstrated.

Xray Process

X-ray slice data is generated using an X-ray source that rotates around the object; X-ray sensors are positioned on the opposite side of the circle from the X-ray source. The earliest sensors were scintillation detectors, with photomultiplier tubes excited by (typically) cesium iodide crystals. Cesium iodide was replaced during the 1980s by ion chambers containing high pressure Xenon gas. These systems were in turn replaced by scintillation systems based on photo diodes instead of photomultipliers and modern scintillation materials with more desirable characteristics. Many data scans are progressively taken as the object is gradually passed through the gantry. They are combined together by the mathematical procedures known as tomographic reconstruction. The data are arranged in a matrix in memory, and each data point is convolved with its neighbours according with a seed algorithm using Fast Fourier Transform techniques. This dramatically increases the resolution of each Voxel (volume element). Then a process known as back projection essentially reverses the acquisition geometry and stores the result in another memory array. This data can then be displayed, photographed, or used as input for further processing, such as multi-planar reconstruction.

Newer machines with faster computer systems and newer software strategies can process not only individual cross sections but continuously changing cross sections as the gantry, with the object to be imaged, is slowly and smoothly slid through the X-ray circle. These are called helical or spiral CT machines. Their computer systems integrate the data of the moving individual slices to generate three dimensional volumetric information (3D-CT scan), in turn viewable from multiple different perspectives on attached CT workstation monitors. This type of data acquisition requires enormous processing power, as the data are arriving in a continuous stream and must be processed in real-time.

In conventional CT machines, an X-ray tube and detector are physically rotated behind a circular shroud (see the image above right); in the electron beam tomography (EBT) the tube is far larger and higher power to support the high temporal resolution. The electron beam is deflected in a hollow funnel-shaped vacuum chamber. X-rays are generated when the beam hits the stationary target. The detector is also stationary. This arrangement can result in very fast scans, but is extremely expensive.

The data stream representing the varying radiographic intensity sensed at the detectors on the opposite side of the circle during each sweep is then computer processed to calculate cross-sectional estimations of the radiographic density, expressed in Hounsfield units. Sweeps cover 360 or just over 180 degrees in conventional machines, 220 degrees in EBT.

CT scanner with cover removed to show the principle of operation

CT is used in medicine as a diagnostic tool and as a guide for interventional procedures. Sometimes contrast materials such as intravenous iodinated contrast are used. This is useful to highlight structures such as blood vessels that otherwise would be difficult to delineate from their surroundings. Using contrast material can also help to obtain functional information about tissues.

Pixels in an image obtained by CT scanning are displayed in terms of relative radiodensity. The pixel itself is displayed according to the mean attenuation of the tissue(s) that it corresponds to on a scale from +3071 (most attenuating) to -1024 (least attenuating) on the Hounsfield scale. Pixel is a two dimensional unit based on the matrix size and the field of view. When the CT slice thickness is also factored in, the unit is known as a Voxel, which is a three dimensional unit. The phenomenon that one part of the detector cannot differentiate between different tissues is called the "Partial Volume Effect". That means that a big amount of cartilage and a thin layer of compact bone can cause the same attenuation in a voxel as hyperdense cartilage alone. Water has an attenuation of 0 Hounsfield units (HU) while air is -1000 HU, cancellous bone is typically +400 HU, cranial bone can reach 2000 HU or more (os temporale) and can cause artifacts. The attenuation of metallic implants depends on atomic number of the element used: Titanium usually has an amount of +1000 HU, iron steel can completely extinguish the X-ray and is therefore responsible for well-known line-artifacts in computed tomograms. Artifacts are caused by abrupt transitions between low- and high-density materials, which results in data values that exceed the dynamic range of the processing electronics.