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.

 

 

 

Mato Grosso do Sul–Brasil–imagens de rios.

 

Amazing Underwater Photos

 

 

 

 

 

 

 

 

 

Promising technology to expand hard cider industry

 

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Bruising from mechanically harvesting cider apples did not affect fruit or juice quality.

A new study by researchers at Washington State University shows that mechanical harvesting of cider apples can provide labor and cost savings without affecting fruit, juice or cider quality.

The study, published in the journal HortTechnology in October, is one of several focused on cider apple production in Washington state. It was conducted in response to growing demand for hard cider apples in the state and nation.

Quenching a thirst

Hard cider consumption is trending steeply upward in the region surrounding food-conscious Seattle, and Washington is part of the nation's hard cider revival. The amount of cider produced in the state tripled between 2007 and 2012.

The rapid expansion means cider apple growers are hard pressed to keep pace with demand. Because cider apples are smaller than dessert apples -- the kind we find in the grocery store for fresh eating -- it takes longer to harvest them. In fact, harvest labor can account for nearly half of the annual costs of an orchard in full production.

Regions like the Skagit Valley in western Washington that don't have large-scale commercial apple production lack experienced apple harvest crews.

"We simply don't have a dedicated agricultural labor market in western Washington," said horticulturalist Carol Miles, the lead author of the study. "High quality and affordable labor to hand-harvest cider apples is difficult to come by and costly."

Miles leads one of a handful of cider apple research programs in the nation, located at the WSU Northwestern Washington Research and Extension Center.

Over-the-row harvesting

Mechanical harvest is a logical solution to this challenge -- except for two complications. First, such a machine doesn't exist for apples, which are generally grown in compact trellis systems, hand-picked and carefully handled to avoid bruising.

The other issue is that mechanical harvest is likely to damage fruit, but just what this means for the final product is unknown.

To address the first challenge, Miles and her team used a mechanical raspberry harvesting machine to pick Brown Snout cider apples, a variety grown at the research center. The machine passes over fruit trees that are no higher than six feet, knocking the apples from trees onto a conveyer belt for collection by workers into tote bins.

Researchers assessed the level of damage to the trees and tested the fruit to see what impact, if any, bruising had on fruit and juice quality.

Olive harvester might be suitable

The two-year study showed that machine harvesting required up to four times less labor than hand harvesting, resulting in an average cost savings of $324 per acre. Bruising did occur on all of the fruit, but it didn't affect the quality of fruit or juice -- whether the apples were processed immediately or cold-stored for two to four weeks before pressing.

Miles noted that modifications to the small fruit mechanical harvester could further improve efficiencies for apple harvest. She dreams of one day testing an olive harvester, which can pass over trees that are 10-12 feet tall -- the common height for modern apple orchards.

If suitable equipment is available and affordable, then mechanical harvesting could be just what the industry needs to expand and keep up with demand for locally grown cider apples.

Technology developed to improve lung cancer detection, treatment

 

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Researchers from Loyola University Chicago Stritch School of Medicine have developed a technology that improves the detection of tumors during radiation therapy for early-stage lung cancer.

John Roeske, PhD, and colleagues presented how they developed and evaluated the technology at the recent annual meeting of the American Society for Therapeutic Radiology and Oncology.

Their approach uses dual-energy imaging combined with fluoroscopy to view tumors during radiation therapy. This technology does not require an X-ray that produces both high-and low-energy images. Existing hardware can be used to eliminate visuals of the ribs and other bones making it easier to see the tumor.

"Dual-energy imaging has been used for decades by radiologists to detect lung tumors," said Roeske, professor and director of Radiation Physics, Department of Radiation Oncology. "When combined with fluoroscopy, the hybrid dual-energy technology can enhance the visibility of tumors to improve treatment for patients."

Roeske and his colleagues have a patent on the technology. They report that if it becomes commercially available, their approach would provide a cost-benefit to hospitals.

"This technology does not require that hospitals replace their standard X-ray machines since the dual-energy images are created using a software approach," Roeske said. "The hybrid technique removes present obstacles making this a great benefit to clinicians and patients."

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Story Source:

The above story is based on materials provided by Loyola University Health System. Note: Materials may be edited for content and length.

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Could Depression Actually Be a Form of Infectious Disease?

 

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Major depressive disorder (MDD) should be re-conceptualized as an infectious disease, according to Turhan Canli, PhD, Associate Professor of Psychology and Radiology at Stony Brook University. In a paper published in Biology of Mood & Anxiety Disorders, Dr.Canli suggests that major depression may result from parasitic, bacterial, or viral infection. He presents examples that illustrate possible pathways by which these microorganisms could contribute to the etiology of MDD.

MDD remains highly prevalent disease with some 15 to 20 percent of the population experiencing MDD at some point. Recurrence is common, and pharmacological treatments have not changed. Because the causal aspects of the disease are not clearly defined, research to find causes remains paramount to help improve treatments.

"Given this track record of MDD, I propose reconceptualizing the condition as some form of infectious disease," said Dr. Canli, who is also Director of Stony Brook's SCAN Center, a member of the Program in Neuroscience, and a Senior Fellow in the Center for Medical Humanities, Compassionate Care, and Bioethics. "Future research should conduct a concerted effort search of parasites, bacteria, or viruses that may play a causal role in the etiology of MDD."

In the paper, Dr. Canli presents three arguments why reconceptualizing MDD as an infectious disease may be a fruitful endeavor.

First, he points out that patients with MDD exhibit illness behavior such as loss of energy, and that inflammatory biomarkers in MDD also suggest an illness-related origin. Second, he describes evidence that parasites, bacteria and viruses that infect humans in a way that alters their emotional behavior. Thirdly, Dr. Canli brings the notion of the human body as an ecosystem for microorganisms and the role of genetics.

Based on these points, Dr. Canli suggests a major research step would be to conduct large-scale studies with depressed patients, controls, and infectious-disease related protocols to determine the association or causal nature of infectious disease and depression.

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Story Source:

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

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Journal Reference:

1. Turhan Canli. Reconceptualizing major depressive disorder as an infectious disease. Biology of Mood & Anxiety Disorders, 2014; 4 (1): 10 DOI: 10.1186/2045-5380-4-10

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