Science and Nature

LOS ANGELES — It may sound like a West Side Story-style love story, but some dogs love big cats.

Cheetahs are the fastest mammals in the world, but they also are the world's biggest scaredy-cats — so much so that they don't breed easily and are in danger of going extinct.

Some zoos are introducing dogs to calm the skittish cats and bring attention to their plight. They're pairing "companion dogs" with some cheetahs to serve as playmates and to provide the cats with guidance.

"It's a love story of one species helping another species survive," said Jack Grisham, vice president of animal collections at the St. Louis Zoo and species survival plan coordinator for cheetahs in North America.

Or, to quote Stephen Stills, it's a matter of loving the one you're with, he said.

"It is all about comforting and reassuring the cheetah," said Janet Rose-Hinostroza, animal training supervisor at the San Diego Zoo Safari Park — the top U.S. breeder of cheetahs in captivity. In the past 40 years, 135 cheetahs have been born at the park's breeding facility.

The cheetahs most often found at zoos and wildlife parks are not considered good breeding candidates, they don't relate well to other cheetahs, or they are abandoned by their mothers, Rose-Hinostroza said. But they seem to take easily to companion dogs and look to the dogs for play and example.

Of the 19 cheetahs at Safari Park, four have dogs. Four of the zoo's cheetahs also have dogs.

The dogs, usually from animal shelters, and cheetah pups generally are introduced when they are about 3 months old.

"In this relationship, the dog is dominant, but we look for dogs that want to be a buddy," Rose-Hinostroza said. "The dog always has the cat's back, but it's never the other way around. Dogs worry about their cats. They protect their cats."

One of the most popular draws at Safari Park is the 100-meter cheetah run where the public gets to see firsthand the speed of "nature's perfect sprinter."

"Speed is incredibly important. It is their survival technique, in a nutshell," Rose-Hinostroza said. "If they can't run, they won't survive. They are not equipped to be confrontational."

A cheetah's claws don't retract, so they have footing that takes them from "zero to 60 in 3.4 seconds," she said.

"That's faster than every single car on the market, and it only takes three steps," Rose-Hinostroza said.

Cheetahs use their tails like a rotor to balance while they are running. Their top speed is 60 to 70 mph, based on size, but they can run that fast only for 20 or 30 seconds. Extending that to a minute or more puts the animal in serious jeopardy of death.

"Overexertion, heat exhaustion can literally cook their organs at that speed," Rose-Hinostroza said. She added the average cheetah chase in the wild is 200 to 300 meters.

Safari Park's cheetahs chase a lure for 100 meters, a sprint that seldom exceeds 6 seconds.

A century ago there were 100,000 cheetahs in the wild, Grisham said. Today there are fewer than 12,000. The species has become extinct in at least 13 countries. There are about 280 captive cheetahs in zoos across the United States.

As captive efforts to save the species continue, Grisham worries there is no wild to send them home to because habitat is being swallowed up by developers and poachers are killing the cats for their fur.

Cheetahs live 12 to 15 years in captivity. Males weigh 120 to 150 pounds, and females 100 to 120 pounds.

The dogs come in all sizes. At Safari Park, the smallest and sweetest is Hopper, a male mutt who weighs 40 pounds. He's teamed with Amara, the toughest female cheetah on the team, Rose-Hinostroza said.

Cheetah females don't go into heat like other cats. Instead, they have to be brought into estrus by a male cheetah, the experts explained. That's why breeding is so hard — because they aren't social animals, they live independently, and they seldom hang out with one another.

Although the dogs and cats live together, they are not always with one another. Dogs have play dates with other dogs and humans. Mealtimes always are spent apart. The dogs eat kibble, and the cheetahs eat steak.

"The dogs are the bosses in these relationships," Rose-Hinostroza said. "If they ate together there would be one really fat dog and a really skinny cheetah."

One of Safari Park's dogs — the only non-shelter dog — is Yeti, an Anatolian shepherd. She works with two cheetahs — Johari and her brother Shiley.

No one is sure when the idea of cheetah dogs started, but Anatolian shepherds helped advance it. The San Diego Zoo was given a pair of cheetahs in 1981 on the condition they be given dogs because they were used to them.

A few decades ago, Dr. Laurie Marker, founder and executive director of the Cheetah Conservation Fund in the southern African nation of Namibia, brought Anatolian shepherds from Turkey and raised them to protect area goat herds.

"The Anatolian shepherd weighs up to 150 pounds and isn't afraid of anything," Grisham said. "They'll square off against lions and leopards. They don't always win, but they are very protective.

"Marker gave the dogs to farmers to protect their herds," Grisham said. When cheetahs came looking for dinner, the dogs scared the cats away and saved the farmer's goats. At the same time, the dogs saved the cats from being killed by the farmers. There was plenty of other food in the wild for the cats, including gazelles, impalas, springhares, birds, warthogs, kudu and hartebeest.

The dogs have helped cheetah conservation in Africa. "For the first time in 30 years, the cheetah population in the wild is on the rise because ranchers don't have to shoot them anymore. They don't need to shoot them. The dog is that effective at keeping the cheetah away from the herd," Rose-Hinostroza said.

Not every zoo that breeds cheetahs uses dogs. The St. Louis Zoo, where Grisham is based, has seven cheetahs but does not use dogs. More than 30 cubs have been born at that zoo.

Visitors can still watch the skittish cats and learn what all the fuss is about, Grisham said.

"It helps us understand the plight of animals in nature. In Africa, cheetahs were treated as vermin for years, like people in the United States treat coyotes," Grisham said.

Reference:

Shelter Dogs Help Cheetahs Survive

The nervous cheetahs who need a canine companion to get them relaxed enough to breed

Lockheed Martin has joined a partnership to develop what it described as “the world’s largest wave energy project” to date, off the Victoria coast in southern Australia. Victorian Wave Partners Ltd. is an Australian special-purpose company owned by Ocean Power Technologies Australasia Pty Ltd., a developer of “wave energy” technology.

OPT’s PowerBuoy system uses a "smart" buoy to convert wave energy into electricity.  The buoy moves up and down with the rising and falling of waves, and the mechanical energy generated by this action drives an electrical generator, which transmits power to shore via an underwater cable.

The system is designed to be electrically tuned on a wave-by-wave basis to maximize the amount of electricity produced. In the Australian development, anticipated peak-power generating capacity is 62.5 megawatts. That would be sufficient to supply 10,000 homes.

The Victorian Wave project is scheduled to be built in three stages, with the first stage producing approximately 2.5 megawatts of peak power.

No starting date has been indicated for the installation.

Lockheed did not reveal the value of its investment.  It will provide overall project management, assist with the design for manufacturing the PowerBuoy systems, lead the production of selected components, and perform system integration of the wave energy converters.

"We are pleased to be working with Lockheed Martin in connection with this exciting project in Australia," explained OPT chief executive Charles F. Dunleavy. "Development of this project draws on core strengths of both our companies and represents an important undertaking for commercialization of the PowerBuoy technology."

Lockheed Martin’s participation in this project is reminiscent of Boeing’s recent participation in a tidal-energy project, though wave power is distinct from tidal power.

Wave power devices extract energy from the surface motion of ocean waves, which is very predictable and reportedly will generate electricity for more hours in a year than wind and solar sources.

"We are applying our design and system integration expertise to commercialize promising, emerging alternative energy technologies, including ocean power," stated Tim Fuhr, director of ocean energy for Lockheed Martin's Mission Systems and Training business. "This project extends our established relationship with OPT and Australian industry, and enables us to demonstrate a clean, efficient energy source for Australia and the world."

UNIVERSITY PARK, Pa. -- For the first time anywhere, a team of chemists and engineers at Penn State has placed tiny synthetic motors inside live human cells, propelled them with ultrasonic waves and steered them magnetically. It's not exactly "Fantastic Voyage," but it's close. The nanomotors, which are rocket-shaped metal particles, move around inside the cells, spinning and battering against the cell membrane.

Nanomotors are controlled, for the first time, inside living cells

"As these nanomotors move around and bump into structures inside the cells, the live cells show internal mechanical responses that no one has seen before," said Tom Mallouk, Evan Pugh Professor of Materials Chemistry and Physics. "This research is a vivid demonstration that it may be possible to use synthetic nanomotors to study cell biology in new ways. We might be able to use nanomotors to treat cancer and other diseases by mechanically manipulating cells from the inside. Nanomotors could perform intracellular surgery and deliver drugs noninvasively to living tissues."

Up until now, Mallouk said, nanomotors have been studied only "in vitro" in a laboratory apparatus, not in living human cells. Chemically powered nanomotors were first developed 10 years ago at Penn State by a team that included chemist Ayusman Sen and physicist Vincent Crespi, in addition to Mallouk.

For their experiments, the researchers use HeLa cells, an immortal line of human cervical cancer cells that typically is used in research studies. These cells ingest the nanomotors, which then move around within the cell tissue, powered by ultrasonic waves. At low ultrasonic power, Mallouk explained, the nanomotors have little effect on the cells. But when the power is increased, the nanomotors spring into action, moving around and bumping into organelles -- structures within a cell that perform specific functions. The nanomotors can act as egg beaters to homogenize the cell's contents, or they can act as battering rams to puncture the cell membrane.\

While ultrasound pulses control whether the nanomotors spin around or whether they move forward, the researchers can control the motors even further by steering them, using magnetic forces. Mallouk and his colleagues also found that the nanomotors can move autonomously -- independently of one another -- an ability that is important for future applications.

"Autonomous motion might help nanomotors selectively destroy the cells that engulf them," Mallouk said. "If you want these motors to seek out and destroy cancer cells, for example, it's better to have them move independently. You don't want a whole mass of them going in one direction."

The ability of nanomotors to affect living cells holds promise for medicine, Mallouk noted.

"One dream application of ours is Fantastic Voyage-style medicine, where nanomotors would cruise around inside the body, communicating with each other and performing various kinds of diagnoses and therapy. There are lots of applications for controlling particles on this small scale, and understanding how it works is what's driving us."

The researchers' findings were published in Angewandte Chemie International Edition on Feb. 10. In addition to Mallouk, co-authors include Penn State researchers Wei Wang, Sixing Li, Suzanne Ahmed, and Tony Jun Huang, as well as Lamar Mair of Weinberg Medical Physics in Maryland. The research was funded by the National Science Foundation (MRSECgrant DMR-0820404), the National Institutes of Health, the Huck Innovative and Transformative Seed Fund (HITS) and Penn State.

Most men don't consider more than one, two or maybe three ways to tie their tie, if they tie one at all—but the fact is, there are far more ways to do it than most would ever imagine and because of that mathematicians have at times set themselves the task of trying to discern if the number is finite, and if so, what that number might be.

Back in 1999, a pair of researches (Yong Mao and Thomas Fink) with the University of Cambridge came up with a mathematical language to describe all the actions that can be performed in tying a tie and used it to calculate that the total number of possible outcomes was a very reasonable 85. In this new effort the researchers say that number is far too small because it leaves out some good possibilities. They've extended the mathematical language and have used it to create a new upper limit—177,147.

Vejdemo-Johansson apparently came to believe that the number produced by Mao and Fink was too small after noting the unique tie knot in the movie "The Matrix Reloaded"—a knot that didn't appear in the researchers list, which meant something wasn't quite right. In reexamining the criteria that Mao and Fink used for inclusion, they noted the pair restricted the number of tucks that would occur at the end of the tie tying, to just one. The pair, it was noted, also assumed that any knot created would naturally be covered in part by a flat section of fabric. Also, they restricted the number of windings that could be made to just eight, believing any more than that would cause the tie to become too short.

Vejdemo-Johansson adjusted the parameters and added nomenclature for describing tie movements and after putting it all together, used their new math language to calculate the new total number of possible tie knots—though, it might not be the last word—some of their parameter assignments, such as setting the maximum winds at 11, for example, could perhaps be adjusted for longer ties, or those made of much thinner material.

Many studies point to the health and psychological benefits of marriage, but the new study published in the journal Families, Systems, & Health on Jan. 13 suggests that marriage may not be as great as it seems health-wise — at least not for men.

The scientists used data from Project EAT that monitored the diet, physical activity, and weight status of about 2,300 young adults in the Midwest. About 35% of the total sample were single or casually dating, 42% were in a committed relationship, and 23% were married.

The results suggest that married men were 25% more likely to be overweight or obese than single men or men in committed relationship. The scientists defined overweight as people having a body mass index over 25.

In the image below the first column of numbers shows the percent of men who are overweight and the last column shows the percent of women who are overweight. You can see that the married men column have the highest rate of obesity at 58.5%.

In the image below the first column of numbers shows the percent of men who eat breakfast and the last column of numbers shows the percent of women who eat breakfast at least five times per week. More than 60% of married eat breakfast regularly. 

There are tons of health benefits that come from eating breakfast, so the results of the study suggest that some married women may have a healthy edge.

This does not mean that being married will suddenly make you fat if you're a man, or make you crave breakfast if you're a woman. There are many other factors at play beyond the scope of the study, including who is likely to get married in the first place, the duration of relationships, and the tendency for people to select a partner based on shared habits.

The scientists found that relationship status made little difference in other health behaviors like eating lots of fruits and vegetables, eating less fast food, and exercising. Next they hope to examine how the quality of the relationship affects the health behaviors of the couple.

The war many organizations and public health care officials have been waging against cigarettes haven't been fruitless.

According to a study by the University of California San Diego, measures like baning smoking in public places and work actually help smokers cut back or entirely quit.

"When there's a total smoking ban in the home, we found that smokers are more likely to reduce tobacco consumption and attempt to quit than when they're allowed to smoke in some parts of the house," said Wael K. Al-Delaimy, MD, PhD, professor and chief of the Division of Global Health in the UC San Diego Department of Family and Preventive Medicine in apress statement. "The same held true when smokers report a total smoking ban in their city or town. Having both home and city bans on smoking appears to be even more effective."

An estimated 43.8 million people or 19 percent of all adults in the United States smoke cigarettes. Smoking is the leading cause of preventable deaths in the United States accounting for more than 440,000 deaths or one in every five deaths in the country each year.

For the study researchers surveyed 1,718 smokers in the state of California. They found that total smoking bans in homes was more effective in reducing smoking and successful quitting than partial bans. Researchers found that smokers were more likely to successfully quite smoking in states where bans were implemented than states where bans were not.

Another observation made in the study was that home smoking bans were more effective in reducing cigarette consumption among females and people above 65 years of age while total state bans were more effective in male smokers quitting.

In 1994, California became the first state to ban smoking and received a very positive response. The benefits of this ban were evident and prevented non-smokers from being affected by second-hand smoking. A previous study found that second-hand smoking, commonly known as passive smoking is more harmful than what people believe. It increases the long-term risk of developing lung disease, such as lung cancer and COPD (chronic obstructive pulmonary disease).

Recently popular coffee café Starbucks banned smoking 25 feet near its stores, Wall Street Journal reported. The ban was enforced across the stores 7,000 company-operated cafes in the U.S.

In Spain the majority of deaths related to cocaine are not correctly certified and therefore up until now very few studies have been carried out that analyse the consequences of consuming these drugs in terms of mortality.

"Death certificates rarely include any reference to these substances in the information contained therein," SINC was informed by Gregorio Barrio, a researcher at the Carlos III Health Institute in Madrid and one of the authors of this new study.

This, says Barrio, is because very often the immediate cause of death in these cases is an unspecified health problem, such as a myocardial infarction or suicide, which may be caused by factors unrelated to cocaine or a number of reasons.

"Also, when signs of cocaine consumption before death are revealed during possible forensic and toxicological investigations, the original certified cause of death generally goes uncorrected, thus being included in mortality statistics devoid of the surname 'cocaine'," adds the researcher.

Faced with the difficulty of directly quantifying the deaths related to cocaine based on general mortality statistics, the researchers compared mortality rates among a group of heroin and cocaine users with that of people among the general population of the same age and sex.

For this study, published in the Journal of Substance Abuse Treatment, two groups of cocaine users were taken, one of 8,825 people that also consumed heroin and another of 11,905 people who did not use this substance.

All the participants were admitted to treatment for psychoactive drug abuse or dependence in Madrid or Barcelona between 1997 and 2007; they were aged between 15 and 49 years at the time of being recruited and were cross-referenced with the general mortality register for the 1997-2008 period, in order to observe their vital condition.

Excess mortality - adjusted death rate ratio between participants and the general population - was considerable in both groups of participants. In fact, the death rate among those who also consumed heroin was 14.3 times higher than for the general population, while among those who did not consume this substance, it was 5.1 times higher.

The results also revealed that was a greater chance of men dying than women among those who also consumed heroin (1.5 times), while no differences were found according to sex among those who did not consume this substance.

The authors stated that the excess mortality found is within the range of the results published in the past in other countries (4-12 times higher).

Apart from the use of heroine, other factors related to the greater risk of death were identified, such as the absence of regular employment, drug use by injection or consuming cocaine on a daily basis.

"This excess mortality may be due to the consumption of cocaine or heroin, but there are also other factors that may be different among the general population and the participants, such as mental disorders, personality traits, social conditions, etc.," said Barrio.

Another interesting finding was that the excess mortality with regard to the general population of the same age and sex was significantly higher among women than among men, particularly among those who consumed cocaine but not heroin (8.6 times in women compared with 3.5 times in men).

"This information does not mean that female cocaine consumers have a significantly greater risk of death than their male counterparts, but that the relative increased risk of female cocaine consumers compared with women in the general population of their same age (with a very low death risk) is higher than the relative increase of consumers compared with men among the general population," he clarified.

For the authors, the conclusions of this work are important because they will enable better estimates to be obtained for mortalities attributable to cocaine and they also show that interventions need to be increased in order to reduce the consumption of these substances and the damage caused by them.

The outstanding feature of this artifical mini brain is its ability to learn by simple principles. "The network-controlled robot is able to link certain external stimuli with behavioral rules," says Professor Martin Paul Nawrot, head of the research team and professor of neuroscience at Freie Universität Berlin. "Much like honeybees learn to associate certain flower colors with tasty nectar, the robot learns to approach certain colored objects and to avoid others."

In the learning experiment, the scientists located the network-controlled robot in the center of a small arena. Red and blue objects were installed on the walls. Once the robot's camera focused on an object with the desired color-red, for instance-, the scientists triggered a light flash. This signal activated a so-called reward sensor nerve cell in the artificial network. The simultaneous processing of red color and the reward now led to specific changes in those parts of the network, which exercised control over the robot wheels. As a consequence, when the robot "saw" another red object, it started to move toward it. Blue items, in contrast, made it move backwards. "Just within seconds, the robot accomplishes the task to find an object in the desired color and to approach it," explains Nawrot. "Only a single learning trial is needed, similar to experimental observations in honeybees."

The current study was carried out at Freie Universität Berlin within an interdisciplinary collaboration between the research groups "Neuroinformatics" (Institute of Biology) led by Professor Martin Paul Nawrot and "Artificial Intelligence" (Institute of Computer Science) led by Professor Raúl Rojas. The scientists are now planning to expand their neural network by supplementing more learning principles. Thus, the mini brain will become even more powerful-and the robot more autonomous.

The Bernstein Focus "Neuronal Basis of Learning" with its project "Insect inspired robots: towards an understanding of memory in decision making" and the Bernstein Center Berlin are part of the National Bernstein Network Computational Neuroscience in Germany. With this funding initiative, the German Federal Ministry of Education and Research has supported the new discipline of Computational Neuroscience since 2004 with more than 170 million Euros.. The network is named after the German physiologist Julius Bernstein (1835-1917)

Citation: L. I. Helgadóttir, J. Haenicke, T. Landgraf, R. Rojas & M. P. Nawrot (2013): Conditioned behavior in a robot controlled by a spiking neural network. 6th International IEEE/EMBS Conference on Neural Engineering (NER), 891-894, http://dx.doi.org/10.1109/NER.2013.6696078

Medical marijuana may be lowering suicide rates in men, according to a new study.

Analysis of data taken from the National Vital Statistics System's Mortality Detail Files indicated that between 1990 and 2007, the growing legalization of medical marijuana in U.S. states resulted in a reduction in suicide rates among men ranging from 9-11 percent.

While data for women remained inconclusive, the analysis concluded that suicides among men aged 20 through 39 years of age fell following the legalization of medical marijuana in some states. Data also indicated that suicide rates remained constant or dropped less significantly in states that did not legalize the drug in comparison with those that did.

Still, much remains unanswered due to the fact man external influences very possibly skewed the data. Instances where even when using medicinal marijuana as a coping mechanism mortality rates increased were also found. The authors of the study admit that this data too could have been influenced by other detrimental habits among depressed individuals.

"The negative relationship between legalization and suicides among young men is consistent with the hypothesis that marijuana can be used to cope with stressful life events. However, this relationship may be explained by alcohol consumption," the researchers wrote.

Currently, 20 of the 50 states have legalized medicinal marijuana, in most cases with some restrictions. According to study co-author Daniel I. Rees Department of Economics, University of Colorado Denver, the effects the legalization of marijuana has on suicide rates among you men remains a topic open for future study.

The study was published in the American Journal of Public Health.

Antiseptic mouthwash is commonly used to quickly refresh and clean the mouth after brushing your teeth in the morning, after eating, and before going to bed. Frequently replacing mouthwash with toothpaste as a quick fix to kill off lingering germs, however, can become a deadly habit that you may need to spit out. According to a recent study published in the journal Free Radical Biology and Medicine, using a mouthwash twice daily — such as Corsodyl — may increase blood pressure up to 3.5 millimeters of mercury (mmHg), raising your heart attack risk.

High blood pressure (HBP) is a serious condition that can lead to coronary heart disease, heart failure, stroke, and a variety of health issues. In the U.S., approximately one in three adults have HBP, often showing no signs or symptoms, says the National Heart, Lung, and Blood Institute. HBP that stays high over time can damage the body and affects how the blood is pushed against the walls of the arteries while the heart pumps blood. A two point raise in blood pressure can enhance the risk of dying from a stroke by 10 percent, and heart disease by seven percent.

Age, family history, being overweight or obese, and physical inactivity are just some of the risk factors that may trigger HBP. People who are overweight or obese require more blood to provide oxygen and nutrients to their tissues, says the Mayo Clinic, while being physically inactive leads to higher heart rates. The higher a person’s heart rate, the harder the heart must work with each contraction, creating a stronger force on the arteries. These two risk factors go hand-in-hand as a lack of physical activity leads to a higher risk of being overweight. Now a team of researchers at Queen Mary University of London believe using antiseptic mouthwash daily could increase the odds of HBP due to a chemical that kills the “good” bacteria responsible for helping the blood vessels relax.

Professor Amrita Ahluwalia, lead author of the study, and her team of researchers, observed the effects of a chlorhexidine-based antiseptic mouthwash — Corsodyl — by measuring the blood pressure of a small cohort of healthy participants during a two-week period. Chlorhexidine is an antiseptic that treats gingivitis and others problems of the mouth and gums. A total of 19 participants were recruited for the study during an initial seven-day control period followed by a seven-day treatment period with the antiseptic mouthwash. The researchers recorded the oral nitrate-reducing capacity and nitrite levels after each study period.

The findings revealed Cordosyl use retracts the oral bacterial conversion from nitrate to nitrate which reduces the plasma nitrate levels that are associated with increases in blood pressure. The mouthwash led the participants’ blood pressure to rise between 2 to 3.5 mmHg, with a noticeable effect found within one day of using the mouthwash twice. 

The study authors believe killing off “good” oral bacteria plays a vital role in determining the plasma nitrate levels, and the bodily control of blood pressure. “Killing off all these bugs each day is a disaster, when small rises in blood pressure have significant impact on morbidity and mortality from heart disease and stroke,” said Ahluwalia, the Daily Mailreported. However, she adds, “We are not telling people to stop using antiseptic mouthwashes if they have a gum or tooth infection — but we would ask why anyone else would want to.”

According to GlaxoSmithKline, Corsodyl manufacturers, the antiseptic mouthwash contains 0.2 percent by volume of chlorhexidine. Corsodyl is recommended for patients with bleeding gums, irritated gums, mouth ulcers and infections, including post-surgery to promote healing, reads the website. The company also makes Corsodyl Daily, which contains 0.06 percent chlorhexidine for everyday use.

The findings of the study do not apply to all mouthwashes because not all mouthwashes contain the chemical chlorhexidine, such as the popular Listerine. The study authors caution other mouthwashes could still produce the same effects as Corsodyl by damaging the mouth’s healthy bacteria.

The American Dental Association does not recommend the use of mouthwash without a dentist’s advice. Depending on each person’s oral hygiene needs, a dentist can suggest using a mouthwash with fluoride or antimicrobial agents as part of their daily oral hygiene routine. Overall, mouthwash users who constantly rely on a battle to hide bad breath should visit their dentist to see if it’s attributed to an underlying cause that could be fixed.

Source: Ahluwalia A, Haydar MA S, Kapil Vikas, Lundberg JO, Pearl V, and Weitzberg E. Physiological role for nitrate-reducing oral bacteria in blood pressure control. Free Radical Biology and Medicine. 2014.