Healthy and Unhealthy Stool

 

The color of your stool can reveal a lot about your health.  Peter Cade/The Image Bank/Getty Images

Updated November 05, 2014.
Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Alternative medicine practitioners often ask clients about their stool as part of the assessment. Find out how they typically interpret green stool, light colored stool, yellow stool, blood in stool, mucus in stool, pencil thin stool, infrequent stool and more. Keep in mind that you should always talk to your doctor about any symptoms you may be experiencing.

What Does an Ideal Bowel Movement Look Like?

An ideal bowel movement is thought to be medium brown, the color of plain cardboard. It leaves the body easily with no straining or discomfort and is the consistency of toothpaste. Approximately 4 to 8 inches long, stool should enter the water smoothly without sticking to the toilet bowl. There should be little gas or odor.

Stool That Sinks Quickly

Rapidly sinking stool can indicate that a person isn't eating enough fiber-rich foods, such as vegetables, fruits, and whole grains or drinking enough water. This stool is often dark because it has been sitting in the intestines for a prolonged time. Learn 5 tips to boost your water intake.

Pale Stool

Stool that light colored (either pale, white, grey or clay colored) may be caused by a lack of bile in stool. Insufficient bile output or bile duct obstruction may be due to conditions such as cholecystitis, gallstones, giardia, parasitic infection, hepatitis, chronic pancreatitis, or cirrhosis. Bile salts secreted by the liver give stool its character brownish color. If there is decreased bile, stool is much lighter in color.

Certain medications such as bismuth subsalicylate (Pepto-Bismol, Kaopectate) or antacids containing aluminum hydroxide may also result in light colored stool. Stool may temporarily become pale after a barium enema test. Pale stool may also be shiny or greasy, float, and be foul smelling, due to undigested fat in the stool (see soft and smelly stool).

Floating Stool

Soft stool that floats, has odor, sticks to the side of the bowl, or is difficult to flush away may mean there is increased fat in the stools, called steatorrhea. Floating stool can also be caused by excess gas. Learn more about the causes of floating stool.

Green Stool

Seeing green stool in the toilet bowl can be alarming, but there are some common reasons why it occurs. Continue reading about the causes of green stool.

Mucus in Stool

Whitish mucus in stool may indicate there inflammation or irritation in the intestinal wall. Mucus in stool can occur with either constipation or diarrhea. Read more about the causes of mucus in stool.

Loose Stool

Two common causes of loose stool or diarrhea are GI tract infections or maldigestion (e.g. lactose intolerance). In traditional Chinese medicine, loose stools, abdominal bloating, lack of energy, and poor appetite can be signs of a condition known as spleen qi deficiency. It doesn't necessarily involve your actual spleen, but it is linked to tiredness and weak digestion brought on by stress and poor diet. Learn more about the causes of loose stool.

Pencil Thin Stool

Excess straining can result in a stool that is long and pencil thin because bearing down causes the anal sphincter to contract and narrow the opening of the anus.

Stool that is pencil thin can be caused by a condition known in traditional Chinese medicine as spleen qi deficiency. Other symptoms of spleen qi deficiency are: easy bruising, mental fogginess, bloating, gas, loose stools, fatigue, poor appetite, loose stools with little odor, symptoms that worsen with stress, undigested food in the stools, and difficulty ending the bowel movement. Spleen qi deficiency can be brought on by stress and overwork.

Eating certain foods in excess is thought to worsen spleen qi deficiency. Offending foods include fried or greasy foods, dairy, raw fruits and vegetables, and cold drinks, all believed to cause "cold" and "dampness" in the body. Dietary treatment of spleen qi deficiency involves eating warm, cooked foods. Ginger tea and cinnamon tea are also warming.

Pencil thin stool can also be caused by a bowel obstruction. Benign rectal polyps, prostate enlargement, colon, rectal or prostate cancer are some of the conditions that can cause obstruction.

Yellow Stool

Yellow stool can indicate that food is passing through the digestive tract relatively quickly. Yellow stool can be found in people with GERD (gastroesophageal reflux disease). Symptoms of GERD include heartburn, chest pain, sore throat, chronic cough, and wheezing. Symptoms are usually worse when lying down or bending. Foods that can worsen GERD symptoms include peppermint, fatty foods, alcohol, coffee, and chocolate.

Yellow stool may also indicate problems with the gallbladder and liver. Bile salts from the liver gives stool its brownish color and when bile output is diminished, it often first appears as yellow stool.

If the stool is also greasy and foul-smelling, there may be excess fat in the stool -- causes include malabsorption disorders such as celiac disease. If the onset is sudden, yellow stool can also be a sign of a bacterial infection in the intestines. Prolonged yellow stool may also be caused by giardia infection or other conditions.

Infrequent Stool

With constipation, infrequent or hard stool is passed often with straining. It is most commonly associated with a lack of both dietary fiber and water. Learn about the causes and remedies for constipation.

Stool That Comes Out in Small Pellets

Pellet stool is stool that comes out in small, round balls rather than long and smooth. It is often due to a lack of dietary fiber, as fiber forms a gel in the intestines when it is fermented by colon bacteria and combined with water. In traditional Chinese medicine, pellet stool is caused by a condition known as liver qi stagnation. Liver qi stagnation can be brought on by stress and a lack of exercise can worsen the problem. Find out more about the causes of pellet stool.

Undigested Food in Stool

Certain plant foods such as corn and grape skins may appear in recognizable pieces in stool, because humans lack the necessary enzymes to digest certain components of plant cell walls. According to Ayurveda, undigested food in stool indicates that agni (the body's digestive fire) is not functioning properly. Ginger tea may be recommended before meals. In traditional Chinese medicine, stool with undigested food may be due to kidney yang deficiency.

Continued on the next page...

The information contained on this site is intended for educational purposes only and is not a substitute for advice, diagnosis or treatment by a licensed physician. It is essential that you discuss with your doctor any symptoms or medical problems that you may be experiencing.

página 2

Updated November 05, 2014.
Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Dark Stool

Stool that is almost black, dark or tarry with a thick consistency may be an indication of bleeding in the upper part of the gastrointestinal tract. The most common medical conditions that cause dark, tar-like stool includes duodenal or gastric ulcer, esophageal varices, Mallory-Weiss tear (which can be linked with alcoholism) and gastritis.

Certain foods, supplements, and medications can temporarily turn stool black. These include:

• Bismuth compounds (e.g. Pepto-Bismol)
• Activated charcoal supplements
• Aspirin and NSAIDS (which can cause bleeding in the stomach)
• Dark foods such as black licorice, blueberries, Oreo cookies, blackberries, grape juice, or blueberries

Dark stool can also occur with constipation. Dark green stool from bile may look black in certain lighting.

If you experience this type of stool and it is not from food or supplements, you should see your doctor as soon as possible.

Bright Red Stool

When there is blood in stool, the color depends on where it is in the digestive tract. Blood from the upper part of the gastrointestinal tract, such as the stomach, will look dark by the time it exits the body as a bowel movement. Blood that is bright red, on the other hand, is more likely to come from bleeding in the lower intestinal tract, such as the large intestine or rectum due to arteriovenous malformations, hemorrhoids, anal fissures, ulcerative colitis, diverticulosis, or colon cancer.

Bright red stool is commonly caused by red food coloring (e.g. red or grape Kool-Aid or other drink mixes, gelatin, ice pops, red candy, red frosting, red licorice), beets, cranberries, or tomato juice or soup. Red medicines such as Amoxicillin may also turn stool red.

Blood in stool doesn't always appear bright red. Blood may be also present in stool but not visible, called "occult" blood. A test called the Fecal Occult Blood Test is used to detect hidden blood in stool.

Go to page 1 for other types of healthy and unhealthy stool

The information contained on this site is intended for educational purposes only and is not a substitute for advice, diagnosis or treatment by a licensed physician. It is essential that you discuss with your doctor any symptoms or medical problems that you may be experiencing.

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What It Means When Your Poop Is Green

 

Peter Cade/The Image Bank/Getty Images

Updated November 06, 2014.
Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

It may be alarming to see green stool (or other types of weird-looking stool) in the toilet but there are some common reasons why it can occur. Here are some of the more likely—and more worrisome—causes of green poop.

The liver secretes a bright green fluid called bile into the small intestine or it is concentrated and stored in the gallbladder.

Bile plays a role in the emulsification, absorption, and digestion of fat and fat soluble vitamins. It helps to soften stools and is responsible for giving stools their characteristic brown color. Bile helps to alkalinize the contents of the intestines. It is made up of bile salts, cholesterol, phospholipids, bilirubin, and electrolytes.

As bile makes its way through to the small intestine and then to the large intestine via the bile ducts, it progressively changes color from green to yellow to brown, due to the action of bacteria in the large intestine on the bile salts.

Green stool often indicates that food has passed through the intestines faster than normal (called decreased bowel transit time), before it could be changed from green to brown. Diarrhea decreases bowel transit time so any condition that causes diarrhea can result in green stool.

Conditions that can cause green stool include:

• Laxative use (e.g. OTC laxatives, insoluble fiber or senna, cascara sagrada, rhubarb) 
• Food poisoning
• Celiac disease
• Watery diarrhea due to Clostridium difficile (e.g. after antibiotic use) 
• Medication side effects (e.g. ciprofloxacin, lexapro, nyquil, zantac)
• Ulcerative colitis
• Crohn's disease
• Malabsorption
• Irritable bowel syndrome
• Bacterial overgrowth
• Infectious diarrhea - especially Salmonella and Giardia
• Traveler's diarrhea
• Cancer
• Graft versus host disease
• Alcohol consumption - ethanol stimulates bowel motility

In some cases, soluble fiber can be increased in the diet to slow transit time. You can get soluble fiber naturally through food such as oats, legumes (peas and other beans), rye, barley, certain fruits and vegetables (prune juice, plums, bananas, berries, carrots, the insides of apples and pears, root vegetables, psyllium seeds. Also see natural remedies for diarrhea for three ways to address diarrhea naturally.

, dyes and supplements that can cause green stool include:

• Spinach, kale and other green vegetables
• Blueberries
• Juicing with green vegetables or fruits or during a juice fast.
• Green or purple food coloring in drink mixes, frozen ice pops, cake icing, blue Gatorade, packaged fruit snacks and other foods.
• Grape-flavored Pedialyte may turn stools bright green.
• Foods that contain the green pigment chlorophyll can also cause temporarily green stool, including algae and grasses such as wheatgrassspirulinabarley grass, seaweed and chlorella.
• Nutritional supplements that contain chlorophyll such as greens powder. 
• Iron supplements and iron-enriched products including baby formula are another cause of green stool. 

When these foods, dyes and supplements are withdrawn from the diet, stool should return to its normal color within a day.

An infant's first bowel movements are typically green-black in color. This is called "meconium" - you should not see it after the infant is three days old.

Keep in mind that you should always discuss with your doctor any symptoms or health issues, including changes in stool.

SEE ALSO: Loose Stool | Floating Stool | Dark or Bright Red Stool | Mucus in Stool | Pellet Stool | More Poop Colors Explained

Disclaimer: The information contained on this site is intended for educational purposes only and is not a substitute for advice, diagnosis or treatment by a licensed physician. It is essential that you discuss with your doctor any symptoms or medical problems that you may be experiencing.

 

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Triple-jetting technology–What is it?

 

Introducing Triple-Jetting Possibilities
Work efficiently, expand production possibilities and achieve ultimate final-product realism.

Triple-jetting 3D printers employ the most advanced PolyJet technology.

Similar to inkjet document printing, PolyJet 3D printing jets micro-layers of liquid photopolymer onto a build tray, then cures it with UV light. The layers build up one at a time to create a fully realized 3D part or prototype. These fully cured parts can be handled and used immediately, without any additional curing or finishing.

Along with the selected model materials, triple-jetting 3D printers also jet a gel-like support material specially formulated to uphold overhangs and complex geometries during the printing process.

When completed, the gel is easily removed by WaterJet.

PolyJet 3D Printing technology benefits manufacturers with its professional quality and speed, high precision and wide choice of materials. PolyJet technology is also renowned for precision prototyping needs, setting the standard for finished-product realism.

 

It allows precise printing with three materials, which means parts can be created with more complexity and
sophistication than ever before – and in a wide range of material properties, from rigid to rubber-like.

These systems enable unprecedented production-floor efficiencies and product-development improvements with astounding versatility. Our newly evolved triple-jetting platform tackles a wide range of manufacturing and
design needs, from ultra-realistic color prototypes and custom jigs and fixtures to injection molds and end-use parts. Build whole products with diverse materials — or mix unrelated parts — in one automated job for maximum uptime and minimum intervention. With easy operation, great material capacity and hot-swapping capabilities, the workflow is as smooth and impressive as the parts you create.

Multiple Material Options for Multi-Material Parts
Rigid Opaque:
Use for precise, accurate tools, like check gauges and assembly fixtures, or for detailed
research models. Combine with other materials for complex parts.
Transparent:
Build clear models or transparent/opaque combinations including opaque model interiors
with transparent exteriors, and parts that allow liquid and air flow monitoring.
Rubber-like:
Enhance tools with soft, non-slip surfaces and add any number of flexible details to models and advanced prototypes.
Specialty materials:
Build custom medical devices and research aids with Bio-compatible material. Choose High temperature material for use with hot liquids and hot air-flow. Conduct advanced prototyping with Simulated Polypropylene.
Digital Materials:
The Connex2 and Connex3 platforms offer over 100 material options — including Digital
ABS™ — perfect for durable end-use parts.
Color:
Objet500 Connex3 is the only 3D printer to offer its extraordinary level of final product realism. Extensive true-to-life color options allow integration of vibrant colors into multimaterial parts — even in translucent or opaque combinations

Learn more at www.stratasys.com

Teens with earlier school start times have higher motor vehicle crash rates

 

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Accident scene (stock image). "When high school classes begin early in the morning, we ask teens to shine when their biological clock tells them to sleep," said American Academy of Sleep Medicine President Dr. Timothy Morgenthaler, a national spokesperson for the Healthy Sleep Project. "Many do not get adequate sleep as a result. Smarter school start times, that are more consistent with sleep needs, will improve students' safety, overall health, mood and academic performance."

A new study suggests that teen drivers who start class earlier in the morning are involved in significantly more motor vehicle accidents than peers with a later high school start time. The results underscore the importance of the "Awake at the Wheel" campaign of the National Healthy Sleep Awareness Project.

Results show that the weekday crash rate for teen drivers during the 2009 to 2010 school year was about 29 percent higher in Chesterfield County, Va., where high school classes began at 7:20 a.m., than in adjacent Henrico County, Va., where classes started at 8:45 a.m. Similar results were found for the 2010 to 2011 school year, when the weekday crash rate for 16-17 year old teens in Chesterfield County was about 27 percent higher than for those in Henrico County. In contrast, there was no difference in adult crash rates in the two counties for either year. A secondary analysis evaluating the causes and types of crashes found that Chesterfield County adolescents had a significantly higher rate of run-off-road crashes, which is a common feature of drowsy driving accidents.

"There are more and more data suggesting that insufficient sleep is common in our teens and that early high school start times are a contributor to teens' reduced sleep," said principal investigator and lead author Dr. Robert Vorona, associate professor in the Division of Sleep Medicine at Eastern Virginia Medical School in Norfolk, Va. "Insufficient sleep appears to have deleterious consequences such as decrements in mood and increased risk taking, impaired academics and increased crash rates."

The results corroborate the findings of a previous study by Vorona's team that evaluated teen crash rates from 2007 to 2008. Results of the current study are published in the November issue of the Journal of Clinical Sleep Medicine.

"When high school classes begin early in the morning, we ask teens to shine when their biological clock tells them to sleep," said American Academy of Sleep Medicine President Dr. Timothy Morgenthaler, a national spokesperson for the Healthy Sleep Project. "Many do not get adequate sleep as a result. Smarter school start times, that are more consistent with sleep needs, will improve students' safety, overall health, mood and academic performance."

Recently the Healthy Sleep Project launched the "Awake at the Wheel" campaign to increase public awareness of the risks of drowsy driving. More details are available at http://www.projecthealthysleep.org.

The study involved an analysis of data provided by the Virginia Department of Motor Vehicles. During both school years there were more than 520 motor vehicle accidents involving teen drivers in Chesterfield County and more than 320 teen crashes in Henrico County.

The American Academy of Sleep Medicine recommends that adolescents get a little more than nine hours of nightly sleep for optimal health and daytime alertness during the critical transition from childhood to adulthood. The AASM advises parents and local school boards to work together to implement high school start times that allow teens to get the healthy sleep they need to meet their full potential.

A new report from the AAA Foundation for Traffic Safety estimates that drowsy driving may cause 328,000 motor vehicle accidents and 6,400 fatal crashes on U.S. roads each year. Previous data analysis by AAA also shows that the prevalence of drowsy driving crashes is highest among drivers between the ages of 16 and 24 years.

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Story Source:

The above story is based on materials provided by American Academy of Sleep Medicine. Note: Materials may be edited for content and length.

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Journal Reference:

1. Robert Daniel Vorona, Mariana Szklo-Coxe, Rajan Lamichhane, J. Catesby Ware, Ann McNallen, David Leszczyszyn. Adolescent Crash Rates and School Start Times in Two Central Virginia Counties, 2009-2011: A Follow-up Study to a Southeastern Virginia Study, 2007-2008. Journal of Clinical Sleep Medicine, 2014; DOI: 10.5664/jcsm.4192

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Chronic kidney disease: Exercise provides clear benefits

 

November 15, 2014

American Society of Nephrology (ASN)

Simple exercises can help improve the health of patients with kidney disease, experts say. Heart disease is the leading cause of death in patients with chronic kidney disease (CKD). Because exercise capacity is significantly reduced in CKD patients, experts examined the effect of 12 months of exercise training on kidney function and measures of heart disease risk in patients with progressive CKD stages 3-4.

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Simple exercises can help improve the health of patients with kidney disease, according to studies that will be presented at ASN Kidney Week 2014 November 11-16 at the Pennsylvania Convention Center in Philadelphia, PA.

Heart disease is the leading cause of death in patients with chronic kidney disease (CKD). Because exercise capacity is significantly reduced in CKD patients, Sharlene Greenwood, MD (King's College Hospital, in London) and her colleagues examined the effect of 12 months of exercise training on kidney function and measures of heart disease risk in patients with progressive CKD stages 3-4. For the study, 20 patients were randomized to a rehabilitation group (REHAB, n = 10) that received exercise training (3 times per week) or standard care (UC, n = 10). A total of 18 participants completed the study (8 from the REHAB group and 10 from the UC group).

The researchers found that 12 months of exercise-based rehabilitation significantly slowed the rate of kidney function decline and improved cardio-respiratory fitness compared with standard care. "Exercise-based rehabilitation has the potential to be a kidney-protective therapy for patients with progressive stages 3-4 CKD, and larger studies are planned," said Dr. Greenwood. "Exercise, besides protecting the kidneys, also will improve fitness, general health, and quality of life and has the potential to reduce cardiovascular risk, a major cause of mortality and morbidity in patients with CKD."

In another study, Francesca Mallamaci, MD (National Research Council Institute of Clinical Physiology, in Italy) and her colleagues tested the effectiveness of a low-intensity, easy-to-implement, home exercise program on physical performance in dialysis patients. For the EXCITE trial, 151 patients were instructed to follow the cadence of an inexpensive metronome while walking, while 146 patients maintained their normal physical activity.

After 6 months, performance in a 6-minute walking test improved in the exercise group (with participants walking 41 meters more in that amount of time), but remained unchanged in the control group. A 'sit to stand' test also improved in the exercise group but not in the control group. "A personalized, low-intensity home exercise program improves physical performance in dialysis patients," the investigators concluded. "The simplicity and adaptability of the program make it suitable to the needs of a high-risk population such as the dialysis population."

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Story Source:

The above story is based on materials provided by American Society of Nephrology (ASN). Note: Materials may be edited for content and length.

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Mentally stressed young women with heart disease more likely to have reduced blood flow to heart

 

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Young women with stable coronary heart disease are more likely than men to have reduced blood flow to the heart if they're under emotional stress, but not physical stress, according to research presented at the American Heart Association's Scientific Sessions 2014.

Compared to men of the same age, when subjected to a mental stress test, women:

• age 55 and younger had three times greater reduction in blood flow to the heart;
• age 56-64 had double the reduction in blood flow to the heart; and
• age 65 and older had no difference in blood flow to the heart.

"Women who develop heart disease at a younger age make up a special high-risk group because they are disproportionally vulnerable to emotional stress," said Viola Vaccarino, M.D., Ph.D., study author and chairwoman of Cardiovascular Research and Epidemiology at Emory University's Rollins School of Public Health in Atlanta, Georgia.

Women generally develop heart disease later in life than men. However, younger women who have premature heart attacks are more likely to die than men of similar age. Risk factors, such as diabetes or high blood pressure, don't explain these mortality differences.

In the study, researchers gave a standardized mental stress test and, on a separate day, a traditional physical stress test (exercise treadmill test or pharmacological stress test) to 534 patients with stable coronary heart disease. For the mental stress protocol, patients were asked to imagine a stressful life situation and deliver a speech about this story in front of a small audience.

Researchers used nuclear imaging to take pictures of the heart while undergoing each of the two stress tests and while at rest. They also monitored heart rate and blood pressure during both mental and physical tests. Then, they analyzed the differences in coronary blood flow based on gender and age. In contrast to the large differences in blood flow observed with mental stress, there were no differences in blood flow with physical stress between women and men.

Young and middle-age women may be more vulnerable to emotional stress because they face considerable burden of stressors in everyday life such as managing kids, marriage, jobs and caring for parents, Vaccarino said. Biology may also play a role -- for example, a greater propensity towards abnormal blood vessel function during emotional stress, such as exaggerated constriction of coronary or peripheral blood vessels.

Healthcare providers should be aware of young and middle-age women's special vulnerability to stress and "ask the questions about psychological stress that often don't get asked," Vaccarino said.

"If they note that their patient is under psychological stress or is depressed, they should advise the woman to get relevant help or support from mental health providers, stress reduction programs or other means."

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Story Source:

The above story is based on materials provided by American Heart Association. Note: Materials may be edited for content and length.

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Running does not lead to knee osteoarthritis, may protect people from developing disease, experts say

 

 

Running as a habitual exercise at any stage in life not only does not increase a person's risk of developing knee osteoarthritis and may even help protect a person from developing the painful disease, according to new research findings presented this week at the American College of Rheumatology Annual Meeting in Boston.

Osteoarthritis, or OA, is the most common joint disease affecting middle-age and older people. It is characterized by progressive damage to the joint cartilage -- the cushioning material at the end of long bones -- and causes changes in the structures around the joint. These changes can include fluid accumulation, bony overgrowth, and loosening and weakness of muscles and tendons, all of which may limit movement and cause pain and swelling.

Knee osteoarthritis is a common form of OA and is caused by cartilage breakdown in the knee joint. Factors that can increase the risk of knee osteoarthritis include: being overweight, age, injury or stress to the joints and having a family history.

Past research on a possible connection between running and knee OA has focused on elite male runners, so those findings may not apply well to the general population, the study's authors noted. Concern that regular running might contribute to knee OA focuses on the fact that chronic, mechanical overloading of the knee joints might be damaging. Yet runners typically have a lower body mass index, or BMI, a factor that protects against developing knee OA.

"Recent CDC guidelines recommend that all adults participate in regular physical activity, as there is definitive evidence that increased physical activity is associated with reduced cardiovascular events and mortality," said Grace Hsiao-Wei Lo, MD, MSc of Baylor College of Medicine and a lead author of the study. "However, the influence of these physical activities on knee OA is unclear. Since running is a common leisure physical activity that involves repetitive loading, which could be harmful to the joint, I was particularly interested in studying how habitual running relates to the development of knee OA."

To find out if habitual running would increase knee OA risk for the general population, the researchers used data from a multicenter observational study, the Osteoarthritis Initiative (OAI). Of the 2,683 participants, 56 percent were female, the mean age was 64.5 and the mean BMI was 28.6. Twenty-nine percent of the participants reported that they ran at some time in their lives.

Patients had knee X-rays, were given symptom assessments, and were asked to complete the Lifetime Physical Activity Questionnaire (LPAQ), identifying the top three most frequently performed physical activities (≥ 10 times in life) they performed at different age ranges throughout their life. Age ranges included 12-18, 19-34, 35-49, and 50 years or older.

At the OAI 48-month visit, knee X-rays were taken and then scored for evidence of radiographic OA using the Kellgren-Lawrence (KL) grade scale. Participants with KL grades of two or higher were considered as having radiographic OA (ROA). The researchers also measured if participants had frequent knee pain at their 48-month visit. Researchers considered a participant to have symptomatic OA (SOA) if they had at least one knee with both ROA and frequent knee pain. Anyone with a total knee replacement was classified as having frequent knee pain, ROA and SOA.

After collecting all the data, the researchers reported that runners, regardless of the age when they ran, had a lower prevalence of knee pain, ROA and SOA than non-runners. For people who had run at any time in their lives, 22.8 percent had SOA compared to 29.8 percent of non-runners. People with the lowest BMI scores were the most likely to report being habitual runners. Regular running, even at a non-elite level, not only does not increase the risk of developing knee OA but may protect against it, the researchers concluded.

"This does not address the question of whether or not running is harmful to people who have pre-existing knee OA," said Dr. Lo. "However, in people who do not have knee OA, there is no reason to restrict participation in habitual running at any time in life from the perspective that it does not appear to be harmful to the knee joint."

'Not just a flavoring: Menthol, Nicotine, Combined Desensitize Airway Receptors

 

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Menthol acts in combination with nicotine to desensitize receptors in lungs' airways that are responsible for nicotine's irritation, say neuroscientists at Georgetown University Medical Center (GUMC).

"We know that a menthol cough drop soothes a scratchy, sore throat. The question we looked at is if and how it works when the irritant is nicotine," says a study author, Kenneth Kellar, PhD, a professor of pharmacology at GUMC.

The findings, which represent work by Georgetown University investigators in GUMC's Department of Pharmacology & Physiology, will be presented by Hoai Ton, PhD, a post-doctoral researcher, on Sunday, Nov. 16 at Neuroscience 2014, the Society for Neuroscience's annual meeting in Washington.

"This study supports the notion that menthol is not just a flavoring, but has a pharmacologic effect," Kellar says.

The U.S. Food and Drug Administration (FDA) is considering restrictions on menthol cigarettes because it has determined that menthol in cigarettes is likely associated with increased initiation and progression to regular cigarette smoking, increased dependence, and reduced success in smoking cessation, especially among African American menthol smokers. But FDA's review of the available research and evidence relating to menthol cigarettes, issued in July 2013, also concluded, "From the available studies, the weight of evidence supports the conclusion that menthol in cigarettes is not associated with an increase in disease risk to the user compared to non-menthol cigarette smokers."

At the same time, the use of menthol cigarettes is especially high among African-American smokers, and research has shown a higher rate of lung cancer in African American smokers compared to other smokers.

"The issue may be that menthol in the presence of nicotine may reduce the irritation enough that a smoker can inhale more deeply, bringing not just nicotine but toxic smoke products farther into the lungs," says co-investigator Gerald Ahern, PhD, an associate professor of pharmacology at GUMC. 'While beyond the scope of this study, it is possible that such deeper inhalation of menthol cigarettes, to the extent it occurs, increases the already substantial health harms from smoking."

The researchers say their study provides a better understanding of how menthol affects the function of the α3β4 receptor, one of the most prevalent nicotinic acetylcholine receptors expressed in the peripheral nervous system. These receptors are expressed in airway sensory nerves as well as other neurons.

"These receptors are also found in the brain, but we don't know yet what effect menthol has on those receptors, or whether they contribute, in any way, to nicotine addiction," Kellar says.

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Story Source:

The above story is based on materials provided by Georgetown University Medical Center. Note: Materials may be edited for content and length.

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Ultraviolet–visible spectroscopy / Microspectrophotometry - What is it?

 

Ultraviolet–visible spectroscopy or ultraviolet-visible spectrophotometry (UV-Vis or UV/Vis) refers to absorption spectroscopy or reflectance spectroscopy in the ultraviolet-visible spectral region. This means it uses light in the visible and adjacent (near-UV and near-infrared [NIR]) ranges. The absorption or reflectance in the visible range directly affects the perceived color of the chemicals involved. In this region of the electromagnetic spectrum, molecules undergo electronic transitions. This technique is complementary to fluorescence spectroscopy, in that fluorescence deals with transitions from the excited state to the ground state, while absorption measures transitions from the ground state to the excited state.

 

Microspectrophotometry

UV-visible spectroscopy of microscopic samples is done by integrating an optical microscope with UV-visible optics, white light sources, a monochromator, and a sensitive detector such as a charge-coupled device (CCD) or photomultiplier tube (PMT). As only a single optical path is available, these are single beam instruments. Modern instruments are capable of measuring UV-visible spectra in both reflectance and transmission of micron-scale sampling areas. The advantages of using such instruments is that they are able to measure microscopic samples but are also able to measure the spectra of larger samples with high spatial resolution. As such, they are used in the forensic laboratory to analyze the dyes and pigments in individual textile fibers, microscopic paint chips and the color of glass fragments. They are also used in materials science and biological research and for determining the energy content of coal and petroleum source rock by measuring the vitrinite reflectance. Microspectrophotometers are used in the semiconductor and micro-optics industries for monitoring the thickness of thin films after they have been deposited. In the semiconductor industry, they are used because the critical dimensions of circuitry is microscopic. A typical test of a semiconductor wafer would entail the acquisition of spectra from many points on a patterned or unpatterned wafer. The thickness of the deposited films may be calculated from the interference pattern of the spectra. A map of the film thickness across the entire wafer can then be generated and used for quality control purposes.

source: Wikipedia

Compact Measurement System for 300-mm Optics

 

Wed, 04/09/2014 - 3:19pm

 

Material Handling Systems

 

4D Technology has introduced a suite of products for high quality, low cost measurement of 300-mm diameter optics. The new measurement system for large optics combines the performance, flexibility and value of 4D Technology’s standard systems.

The system was designed around a standard, 100-mm aperture AccuFiz interferometer to take advantage of its high wavefront quality and reliability. A series of precision components were developed which enable measurement of large afocal optics and large diameter curved surfaces (using CGH null optics), as well as the entire range of optics that can be measured with the standard AccuFiz in stand-alone mode.

The suite of 300-mm components includes a compact, high performance 100- to 300-mm Beam Expander which can be used in horizontal or look-down measurement configurations. Kinematic mounting makes it possible to quickly remove the AccuFiz for free-standing operation, then to return it to the beam expander with no need for re-alignment. A visible coarse alignment laser is also available to quickly position the reference and test optics for rapid test setup.

The new 300-mm Rotational Mounts provide highly repeatable tip, tilt and rotation control of the test and reference optics. Precise adjustments enable 3-Flat Testing when extremely high accuracy measurement is required. The External Phase Shifting Mount adds the ability to measure in remote cavity setups.

All components were optimized for the AccuFiz but can also be adapted for use with other manufacturers' 100-mm aperture interferometers.

4D Technology Corp.