The primary routes of exposure to nitrates and nitrites may differ depending on occupational and non occupational factors. Non-occupational factors may include:
Hobbies (such as gardening, arc welding, etc.),
History of inhalational drug use,
Source of drinking/cooking water and how it is supplied,
The chemical form of the nitrates and nitrites.
Occupational and Paraoccupational Exposures
Occupational exposure occurs primarily through the inhalation and dermal routes. Explosive and fertilizer industry workers may be exposed to nitrate through inhalation of dusts containing nitrate salts. Dusts can also dissolve in sweat exposing skin to concentrated solutions of the salts. Farmers may experience periodic exposures depending on their activities, especially with regard to the handling of fertilizers. Exposure of family members to nitrates from dusts brought home on work clothes has been reported.
The primary route of non-occupational exposure is ingestion of water or foodstuffs that contain high levels of nitrates or nitrites. Inhalation exposures may occur from inhalant drug use and dermal exposures may occur from some topical medications. These would be special instances and not the primary routes of exposure for the general population.
Primary occupational routes of exposure to nitrates and nitrites include inhalation and dermal routes.
The primary route of exposure to nitrates and nitrites for the general population is ingestion.
Inhalation and dermal exposures have been reported in non-occupational settings under certain circumstances, but are not the primary routes of exposure for the general population.
Understanding the environmental fate of nitrates and nitrites may help pinpoint potential sources of exposure. This would be important in assessment of patient exposure risk, prevention and mitigation of nitrate / nitrite overexposure and in the prevention of adverse health effects from exposure.
Environmental Nitrogen Cycle
In general, the following describes the activity of nitrates and nitrites in the environment. Microbial action in soil or water decomposes wastes containing organic nitrogen into ammonia, which is then oxidized to nitrite and nitrate.
Because nitrite is easily oxidized to nitrate, nitrate is the compound predominantly found in groundwater and surface waters.
Contamination with nitrogen-containing fertilizers (e.g. potassium nitrate and ammonium nitrate), or animal or human organic wastes, can raise the concentration of nitrate in water.
Nitrate-containing compounds in the soil are generally water soluble and readily migrate with groundwater.
Shallow, rural domestic wells are those most likely to be contaminated with nitrates, especially in areas where nitrogen-based fertilizers are widely used.
Approximately 15 percent of Americans rely on their own private drinking water supplies which are not subject to U.S. Environmental Protection Agency (EPA) standards, although some state and local governments do set guidelines to protect users of these wells.
In agricultural areas, nitrogen-based fertilizers are a major source of contamination for shallow groundwater aquifers that provide drinking water.
A recent United States Geological Survey study showed that 7 percent of 2,388 domestic wells and about 3 percent of 384 public-supply wells nationwide were contaminated with nitrate levels above the EPA drinking water standard of 10 parts per million (ppm) or 10 mg/L.
Elevated concentrations were most common in domestic wells that were shallow (less than 100 feet deep) and located in agricultural areas because of relatively large nitrogen sources, including septic systems, fertilizer use, and livestock.
Although suppliers of public water sources are required to monitor nitrate concentrations regularly, few private rural wells are routinely tested for nitrates.
During spring melt or drought conditions, both domestic wells and public water systems using surface water can show increased nitrate levels.
Drinking water contaminated by boiler fluid additives may also contain increased levels of nitrites.
Mixtures of nitrates / nitrites with other well contaminants such as pesticides and VOCs have been reported.
Nitrate and nitrite overexposure has been reported via ingestion of foods containing high levels of nitrates and nitrites. Inorganic nitrates and nitrites present in contaminated soil and water can be taken up by plants, especially green leafy vegetables and beet root.
Contaminated foodstuffs, prepared baby foods, and sausage / meats preserved with nitrates and nitrites have caused overexposure in children.
Although vegetables are seldom a source of acute toxicity in adults, they account for about 80% of the nitrates in a typical human diet.
Celery, spinach lettuce, red beetroot and other vegetables have naturally greater nitrate content than other plant foods do.
The remainder of the nitrate in a typical diet comes from drinking water (about 21%) and from meat and meat products (about 6%) in which sodium nitrate is used as a preservative and color- enhancing agent.
For infants who are bottle-fed, however, the major source of nitrate exposure is from contaminated drinking water used to dilute formula.
Bottled water is regulated by the U.S. Food and Drug Administration (FDA) as a food. It is monitored for nitrates, nitrites and total nitrates / nitrites.
Nitrate or nitrite exposure can occur from certain medications and volatile nitrite inhalants.
Accidental and inadvertent exposures to nitrites as well as ingestion in suicide attempts have been reported.
Deliberate abuse of volatile nitrites (amyl, butyl, and isobutyl nitrites) frequently occurs. Amyl nitrite (nicknamed by some as “poppers”) is used commercially as a vasodilator and butyl / isobutyl nitrites can be found in products such as room air fresheners.
Fatalities have been reported in adults exposed to nitrates in burn therapy; however infants and children are especially susceptible to adverse health effects from exposure to topical silver nitrate used in burn therapy.
Other medications implicated in methemoglobinemia include:
Quinone derivatives (antimalarials),
Bismuth subnitrite (antidiarrheal),
Ammonium nitrate (diuretic),
Amyl and sodium nitrites (antidotes for cyanide and hydrogen sulfide poisoning),
Isosorbide dinitrate/tetranitrates (vasodilators used in coronary artery disease therapy),
Benzocaine (local anesthetic), and
Other possible sources of exposure include ammonium nitrate found in cold packs and nitrous gases used in arc welding.
An ethyl nitrite folk remedy called “sweet spirits of nitre” has caused fatalities.
Shallow, rural domestic wells are those most likely to be contaminated with nitrates, especially in areas where nitrogen based fertilizers are in widespread use.
Other nitrate sources in well water include seepage from septic sewer systems and animal wastes.
Foodstuffs high in nitrates, home prepared baby foods, and sausage/meats preserved with nitrates and nitrites have caused overexposure in children.
Nitrate or nitrite exposure can occur from certain medications and volatile nitrite inhalants.
Leading neuroscientist Matthew Walker explains why sleep deprivation is increasing our risk of cancer, heart attack and Alzheimer’s – and what you can do about it.
Matthew Walker has learned to dread the question “What do you do?” At parties, it signals the end of his evening; thereafter, his new acquaintance will inevitably cling to him like ivy. On an aeroplane, it usually means that while everyone else watches movies or reads a thriller, he will find himself running an hours-long salon for the benefit of passengers and crew alike. “I’ve begun to lie,” he says. “Seriously. I just tell people I’m a dolphin trainer. It’s better for everyone.”
Walker is a sleep scientist. To be specific, he is the director of the Center for Human Sleep Science at the University of California, Berkeley, a research institute whose goal – possibly unachievable – is to understand everything about sleep’s impact on us, from birth to death, in sickness and health. No wonder, then, that people long for his counsel. As the line between work and leisure grows ever more blurred, it is rare to meet a person who doesn’t worry about their sleep. But even as we contemplate the shadows beneath our eyes, most of us don’t know the half of it – and perhaps this is the real reason he has stopped telling strangers how he makes his living. When Walker talks about sleep, he can’t in all conscience, limit himself to whispering comforting nothings about camomile tea and warm baths. It’s his conviction that we are in the midst of a “catastrophic sleep-loss epidemic”, the consequences of which are far graver than any of us could imagine. This situation, he believes, is only likely to change if government gets involved.
Walker has spent the last four and a half years writing Why We Sleep, a complex but urgent book that examines the effects of this epidemic close up, the idea being that once people know of the powerful links between sleep loss and, among other things, Alzheimer’s disease, cancer, diabetes, obesity and poor mental health, they will try harder to get the recommended eight hours a night (sleep deprivation, amazing as this may sound to Donald Trump types, constitutes anything less than seven hours). But, in the end, the individual can achieve only so much. Walker wants major institutions and law-makers to take up his ideas, too. “No aspect of our biology is left unscathed by sleep deprivation,” he says. “It sinks down into every possible nook and cranny. And yet no one is doing anything about it. Things have to change: in the workplace and our communities, our homes and families. But when did you ever see an NHS poster urging sleep on people? When did a doctor prescribe, not sleeping pills, but sleep itself? It needs to be prioritised, even incentivised. Sleep loss costs the UK economy over £30bn a year in lost revenue, or 2% of GDP. I could double the NHS budget if only they would institute policies to mandate or powerfully encourage sleep.”
Why, exactly, are we so sleep-deprived? What has happened over the course of the last 75 years? In 1942, less than 8% of the population was trying to survive on six hours or less sleep a night; in 2017, almost one in two people is. The reasons are seemingly obvious. “First, we electrified the night,” Walker says. “Light is a profound degrader of our sleep. Second, there is the issue of work: not only the porous borders between when you start and finish, but longer commuter times, too. No one wants to give up time with their family or entertainment, so they give up sleep instead. And anxiety plays a part. We’re a lonelier, more depressed society. Alcohol and caffeine are more widely available. All these are the enemies of sleep.”
But Walker believes, too, that in the developed world sleep is strongly associated with weakness, even shame. “We have stigmatised sleep with the label of laziness. We want to seem busy, and one way we express that is by proclaiming how little sleep we’re getting. It’s a badge of honour. When I give lectures, people will wait behind until there is no one around and then tell me quietly: ‘I seem to be one of those people who need eight or nine hours’ sleep.’ It’s embarrassing to say it in public. They would rather wait 45 minutes for the confessional. They’re convinced that they’re abnormal, and why wouldn’t they be? We chastise people for sleeping what are, after all, only sufficient amounts. We think of them as slothful. No one would look at an infant baby asleep, and say ‘What a lazy baby!’ We know sleeping is non-negotiable for a baby. But that notion is quickly abandoned [as we grow up]. Humans are the only species that deliberately deprive themselves of sleep for no apparent reason.” In case you’re wondering, the number of people who can survive on five hours of sleep or less without any impairment, expressed as a percent of the population and rounded to a whole number, is zero.
The world of sleep science is still relatively small. But it is growing exponentially, thanks both to demand (the multifarious and growing pressures caused by the epidemic) and to new technology (such as electrical and magnetic brain stimulators), which enables researchers to have what Walker describes as “VIP access” to the sleeping brain. Walker, who is 44 and was born in Liverpool, has been in the field for more than 20 years, having published his first research paper at the age of just 21. “I would love to tell you that I was fascinated by conscious states from childhood,” he says. “But in truth, it was accidental.” He started out studying for a medical degree in Nottingham. But having discovered that doctoring wasn’t for him – he was more enthralled by questions than by answers – he switched to neuroscience, and after graduation, began a PhD in neurophysiology supported by the Medical Research Council. It was while working on this that he stumbled into the realm of sleep.
“I was looking at the brainwave patterns of people with different forms of dementia, but I was failing miserably at finding any difference between them,” he recalls now. One night, however, he read a scientific paper that changed everything. It described which parts of the brain were being attacked by these different types of dementia: “Some were attacking parts of the brain that had to do with controlled sleep, while other types left those sleep centres unaffected. I realised my mistake. I had been measuring the brainwave activity of my patients while they were awake, when I should have been doing so while they were asleep.” Over the next six months, Walker taught himself how to set up a sleep laboratory and, sure enough, the recordings he made in it subsequently spoke loudly of a clear difference between patients. Sleep, it seemed, could be a new early diagnostic litmus test for different subtypes of dementia.
After this, sleep became his obsession. “Only then did I ask: what is this thing called sleep, and what does it do? I was always curious, annoyingly so, but when I started to read about sleep, I would look up and hours would have gone by. No one could answer the simple question: why do we sleep? That seemed to me to be the greatest scientific mystery. I was going to attack it, and I was going to do that in two years. But I was naive. I didn’t realise that some of the greatest scientific minds had been trying to do the same thing for their entire careers. That was two decades ago, and I’m still cracking away.” After gaining his doctorate, he moved to the US. Formerly a professor of psychiatry at Harvard Medical School, he is now professor of neuroscience and psychology at the University of California.
Does his obsession extend to the bedroom? Does he take his own advice when it comes to sleep? “Yes. I give myself a non-negotiable eight-hour sleep opportunity every night, and I keep very regular hours: if there is one thing I tell people, it’s to go to bed and to wake up at the same time every day, no matter what. I take my sleep incredibly seriously because I have seen the evidence. Once you know that after just one night of only four or five hours’ sleep, your natural killer cells – the ones that attack the cancer cells that appear in your body every day – drop by 70%, or that a lack of sleep is linked to cancer of the bowel, prostate and breast, or even just that the World Health Organisation has classed any form of night-time shift work as a probable carcinogen, how could you do anything else?”
There is, however, a sting in the tale. Should his eyelids fail to close, Walker admits that he can be a touch “Woody Allen-neurotic”. When, for instance, he came to London over the summer, he found himself jet-lagged and wide awake in his hotel room at two o’clock in the morning. His problem then, as always in these situations, was that he knew too much. His brain began to race. “I thought: my orexin isn’t being turned off, the sensory gate of my thalamus is wedged open, my dorsolateral prefrontal cortex won’t shut down, and my melatonin surge won’t happen for another seven hours.” What did he do? In the end, it seems, even world experts in sleep act just like the rest of us when struck by the curse of insomnia. He turned on a light and read for a while.
Will “Why We Sleep” have the impact its author hopes? I’m not sure: the science bits, it must be said, require some concentration. But what I can tell you is that it had a powerful effect on me. After reading it, I was absolutely determined to go to bed earlier – a regime to which I am sticking determinedly. In a way, I was prepared for this. I first encountered Walker some months ago, when he spoke at an event at Somerset House in London, and he struck me then as both passionate and convincing (our later interview takes place via Skype from the basement of his “sleep centre”, a spot which, with its bedrooms off a long corridor, apparently resembles the ward of a private hospital). But in another way, it was unexpected. I am mostly immune to health advice. Inside my head, there is always a voice that says “just enjoy life while it lasts”.
The evidence Walker presents, however, is enough to send anyone early to bed. It’s no kind of choice at all. Without sleep, there is low energy and disease. With sleep, there is vitality and health. More than 20 large scale epidemiological studies all report the same clear relationship: the shorter your sleep, the shorter your life. To take just one example, adults aged 45 years or older who sleep less than six hours a night are 200% more likely to have a heart attack or stroke in their lifetime, as compared with those sleeping seven or eight hours a night (part of the reason for this has to do with blood pressure: even just one night of modest sleep reduction will speed the rate of a person’s heart, hour upon hour, and significantly increase their blood pressure).
A lack of sleep also appears to hijack the body’s effective control of blood sugar, the cells of the sleep-deprived appearing, in experiments, to become less responsive to insulin, and thus to cause a prediabetic state of hyperglycaemia. When your sleep becomes short, moreover, you are susceptible to weight gain. Among the reasons for this are the fact that inadequate sleep decreases levels of the satiety-signalling hormone, leptin, and increases levels of the hunger-signalling hormone, ghrelin. “I’m not going to say that the obesity crisis is caused by the sleep-loss epidemic alone,” says Walker. “It’s not. However, processed food and sedentary lifestyles do not adequately explain its rise. Something is missing. It’s now clear that sleep is that third ingredient.” Tiredness, of course, also affects motivation.
Sleep has a powerful effect on the immune system, which is why, when we have flu, our first instinct is to go to bed: our body is trying to sleep itself well. Reduce sleep even for a single night, and your resilience is drastically reduced. If you are tired, you are more likely to catch a cold. The well-rested also respond better to the flu vaccine. As Walker has already said, more gravely, studies show that short sleep can affect our cancer-fighting immune cells. A number of epidemiological studies have reported that night-time shift work and the disruption to circadian sleep and rhythms that it causes increase the odds of developing cancers including breast, prostate, endometrium and colon.
Getting too little sleep across the adult lifespan will significantly raise your risk of developing Alzheimer’s disease. The reasons for this are difficult to summarise, but in essence it has to do with the amyloid deposits (a toxin protein) that accumulate in the brains of those suffering from the disease, killing the surrounding cells. During deep sleep, such deposits are effectively cleaned from the brain. What occurs in an Alzheimer’s patient is a kind of vicious circle. Without sufficient sleep, these plaques build up, especially in the brain’s deep-sleep-generating regions, attacking and degrading them. The loss of deep sleep caused by this assault therefore lessens our ability to remove them from the brain at night. More amyloid, less deep sleep; less deep sleep, more amyloid, and so on. (In his book, Walker notes “unscientifically” that he has always found it curious that Margaret Thatcher and Ronald Reagan, both of whom were vocal about how little sleep they needed, both went on to develop the disease; it is, moreover, a myth that older adults need less sleep.) Away from dementia, sleep aids our ability to make new memories, and restores our capacity for learning.
And then there is sleep’s effect on mental health. When your mother told you that everything would look better in the morning, she was wise. Walker’s book includes a long section on dreams (which, says Walker, contrary to Dr Freud, cannot be analysed). Here he details the various ways in which the dream state connects to creativity. He also suggests that dreaming is a soothing balm. If we sleep to remember (see above), then we also sleep to forget. Deep sleep – the part when we begin to dream – is a therapeutic state during which we cast off the emotional charge of our experiences, making them easier to bear. Sleep, or a lack of it, also affects our mood more generally. Brain scans carried out by Walker revealed a 60% amplification in the reactivity of the amygdala – a key spot for triggering anger and rage – in those who were sleep-deprived. In children, sleeplessness has been linked to aggression and bullying; in adolescents, to suicidal thoughts. Insufficient sleep is also associated with relapse in addiction disorders. A prevailing view in psychiatry is that mental disorders cause sleep disruption. But Walker believes it is, in fact, a two-way street. Regulated sleep can improve the health of, for instance, those with bipolar disorder.
I’ve mentioned deep sleep in this (too brief) summary several times. What is it, exactly? We sleep in 90-minute cycles, and it’s only towards the end of each one of these that we go into deep sleep. Each cycle comprises two kinds of sleep. First, there is NREM sleep (non-rapid eye movement sleep); this is then followed by REM (rapid eye movement) sleep. When Walker talks about these cycles, which still have their mysteries, his voice changes. He sounds bewitched, almost dazed.
“During NREM sleep, your brain goes into this incredible synchronised pattern of rhythmic chanting,” he says. “There’s a remarkable unity across the surface of the brain, like a deep, slow mantra. Researchers were once fooled that this state was similar to a coma. But nothing could be further from the truth. Vast amounts of memory processing is going on. To produce these brainwaves, hundreds of thousands of cells all sing together, and then go silent, and on and on. Meanwhile, your body settles into this lovely low state of energy, the best blood-pressure medicine you could ever hope for. REM sleep, on the other hand, is sometimes known as paradoxical sleep, because the brain patterns are identical to when you’re awake. It’s an incredibly active brain state. Your heart and nervous system go through spurts of activity: we’re still not exactly sure why.”
Does the 90-minute cycle mean that so-called power naps are worthless? “They can take the edge off basic sleepiness. But you need 90 minutes to get to deep sleep, and one cycle isn’t enough to do all the work. You need four or five cycles to get all the benefit.” Is it possible to have too much sleep? This is unclear. “There is no good evidence at the moment. But I do think 14 hours is too much. Too much water can kill you, and too much food, and I think ultimately the same will prove to be true for sleep.” How is it possible to tell if a person is sleep-deprived? Walker thinks we should trust our instincts. Those who would sleep on if their alarm clock was turned off are simply not getting enough. Ditto those who need caffeine in the afternoon to stay awake. “I see it all the time,” he says. “I get on a flight at 10am when people should be at peak alert, and I look around, and half of the plane has immediately fallen asleep.”
So what can the individual do? First, they should avoid pulling “all-nighters”, at their desks or on the dancefloor. After being awake for 19 hours, you’re as cognitively impaired as someone who is drunk. Second, they should start thinking about sleep as a kind of work, like going to the gym (with the key difference that it is both free and, if you’re me, enjoyable). “People use alarms to wake up,” Walker says. “So why don’t we have a bedtime alarm to tell us we’ve got half an hour, that we should start cycling down?” We should start thinking of midnight more in terms of its original meaning: as the middle of the night. Schools should consider later starts for students; such delays correlate with improved IQs. Companies should think about rewarding sleep. Productivity will rise, and motivation, creativity and even levels of honesty will be improved. Sleep can be measured using tracking devices, and some far-sighted companies in the US already give employees time off if they clock enough of it. Sleeping pills, by the way, are to be avoided. Among other things, they can have a deleterious effect on memory.
Those who are focused on so-called “clean” sleep are determined to outlaw mobiles and computers from the bedroom – and quite right, too, given the effect of LED-emitting devices on melatonin, the sleep-inducing hormone. Ultimately, though, Walker believes that technology will be sleep’s saviour. “There is going to be a revolution in the quantified self in industrial nations,” he says. “We will know everything about our bodies from one day to the next in high fidelity. That will be a seismic shift, and we will then start to develop methods by which we can amplify different components of human sleep, and do that from the bedside. Sleep will come to be seen as a preventive medicine.”
What questions does Walker still most want to answer? For a while, he is quiet. “It’s so difficult,” he says, with a sigh. “There are so many. I would still like to know where we go, psychologically and physiologically, when we dream. Dreaming is the second state of human consciousness, and we have only scratched the surface so far. But I would also like to find out when sleep emerged. I like to posit a ridiculous theory, which is: perhaps sleep did not evolve. Perhaps it was the thing from which wakefulness emerged.” He laughs. “If I could have some kind of medical Tardis and go back in time to look at that, well, I would sleep better at night.”
Sleep in numbers:
■ Two-thirds of adults in developed nations fail to obtain the nightly eight hours of sleep recommended by the World Health Organisation.
■ An adult sleeping only 6.75 hours a night would be predicted to live only to their early 60s without medical intervention.
■ A 2013 study reported that men who slept too little had a sperm count 29% lower than those who regularly get a full and restful night’s sleep.
■ If you drive a car when you have had less than five hours’ sleep, you are 4.3 times more likely to be involved in a crash. If you drive having had four hours, you are 11.5 times more likely to be involved in an accident.
■ A hot bath aids sleep not because it makes you warm, but because your dilated blood vessels radiate inner heat, and your core body temperature drops. To successfully initiate sleep, your core temperature needs to drop about 1C.
■ The time taken to reach physical exhaustion by athletes who obtain anything less than eight hours of sleep, and especially less than six hours, drops by 10-30%.
■ There are now more than 100 diagnosed sleep disorders, of which insomnia is the most common.
■ Morning types, who prefer to awake at or around dawn, make up about 40% of the population. Evening types, who prefer to go to bed late and wake up late, account for about 30%. The remaining 30% lie somewhere in between.
The Soeks Ecovisor F4 is a handy device to have at home which carries out 4 important environmental tests. Namely: nitrate tester, dosimeter, EMF & water quality tester. The device is compact and easy to use. It features an intuitive touchscreen. To turn it on, you press and hold the OK button until it lights up. There is no setting up of any kind required, this device is ready to use straight out of the box.
CPAP, or continuous positive airway pressure, is a treatment that uses mild air pressure to keep the airways open. When a person sleeps, the muscles of the entire body relaxes. This includes the upper airway muscles surrounding the throat. These muscles may relax enough to collapse on the airway causing an obstruction of oxygen into the lungs and carbon dioxide out of the lungs; This is called obstructive sleep apnea (OSA). CPAP helps to prevent this collapse by pushing air into the throat creating an air stent. Once the airway is open, the person will be able breathe easily as he/she sleeps.
CPAP treatment involves a CPAP machine, which has three main parts:
A mask or other device that fits over your nose or your nose and mouth. Straps keep the mask in place while you’re wearing it.
A tube that connects the mask to the machine’s motor.
A motor that blows air into the tube.
Some CPAP machines have other features as well, such as heated humidifiers. CPAP machines can be small. They are also lightweight and fairly quiet.
CPAP is often the best treatment for obstructive sleep apnea. Sleep apnea is a common disorder that causes pauses in breathing or shallow breaths while you sleep. As a result, not enough oxygen reaches your lungs.
In obstructive sleep apnea, your airway collapses or is blocked during sleep. When you try to breathe, any air that squeezes past the blockage can cause loud snoring. Your snoring may wake other people in the house.
The mild pressure from CPAP can prevent your airway from collapsing or becoming blocked.
The animation below shows how CPAP works to treat sleep apnea. Click the “start” button to play the animation. Written and spoken explanations are provided with each frame. Use the buttons in the lower right corner to pause, restart, or replay the animation, or use the scroll bar below the buttons to move through the frames.
If your doctor prescribes CPAP, you’ll work with someone from a home equipment provider to select a CPAP machine. Home equipment providers sometimes are called durable medical equipment, or DME.
Your doctor will work with you to make sure the settings that he or she prescribes for your CPAP machine are correct. He or she may recommend an overnight sleep study to find the correct settings for you. Your doctor will want to make sure the air pressure from the machine is just enough to keep your airway open while you sleep.
There are many kinds of CPAP machines and masks. Let your home medical provider know if you’re not happy with the type you’re using. He or she may suggest switching to a different type that might work better for you.
CPAP has many benefits. It can:
Keep your airway open while you sleep
Correct snoring so others in your household can sleep
Improve your quality of sleep
Relieve sleep apnea symptoms, such as excessive daytime sleepiness
Decrease or prevent high blood pressure
Many people who use CPAP report feel more energetic once they begin treatment. They’re more attentive and better able to work during the day. They also report fewer complaints from bed partners about snoring and sleep disruption.
Q：What is the difference between lithium rechargeable batteries and other rechargeable batteries?
A：First of all, this product belongs to the “polymer lithium ion battery,” namely “lithium battery “. Whereas the “rechargeable battery” refers to nickel-metal hydride or nickel-cadmium batteries, which are fundamentally different. Compared with NiMH or NiCd batteries, the lithium battery has such characteristics as high energy density, long cycle life, no memory effect, quick charging speed, ultra-low self-discharge, light weight and environment-friendly. In other word, the phone battery we use now is basically the lithium battery, which is well understood. The phone battery is also developed from nickel-cadmium and nickel hydrogen batteries. “Lithium battery” represents the best battery energy technology at present.
Q：Before that, is there no AA or AAA rechargeable lithium battery?
A：All along, AA or AAA batteries have no lithium batteries in real sense, mainly because the electronic devices on the market using standardized batteries are all designed based on the voltage characteristics of dry batteries (Single voltage of 1.5V). Compared to the traditional standardized batteries, lithium-ion battery’s output voltage is higher (Single voltage of 3.7V). This unique chemical characteristic makes it, the best contemporary energy, have not been possible to enter this field, resulting in serious deficiencies of lithium-ion rechargeable battery in the application field of standardized cylindrical battery.
Q：How can Lithium Polymer Battery be in common use?
A：The 1.5V universal polymer lithium-ion batteries are the major research after years of exploration and research in seeking optimal power solution to portable electronics. It adopts the voltage conversion technology, converting the output voltage of 3.7V into 1.5V, which is fully compatible and alternative to traditional batteries. It has completed a great creation in the field of traditional standard batteries, making the lithium battery step forward to be universal.
Q：What is the difference between polymer lithium ion battery and ordinary lithium ion battery?
A：According to different electrolyte materials, lithium-ion batteries can be divided into polymer lithium ion battery (PLIB), and Li-ion battery (LIB). Ordinary lithium-ion battery refers to liquid lithium battery. In contrast, polymer lithium-ion battery has such characteristics as high energy density and good safety performance. Its quality increases by 20% compared with ordinary lithium-ion (liquid) battery.
Q：How long does it take to charge batteries?
A：It takes about 3 hours to fully charge AA battery and about 2 hours to fully charge AAA battery.
Tips: Due to the special charging characteristics of lithium battery, when the charging time reaches half of the entire charge cycle, the battery has reached more than 85% of the full electric quantity. So in the case of emergencies, it just need half the charging time, thus saving your valuable time.
Q：What does the dual voltage of 1.5V / 3.7V on the battery label mean?
A：There are two sets of output voltage on the positive electrode of lithium batteries. The protruding one of 1.5V is universal battery voltage, users can use it normally, and the other is 3.7V in the groove, which is used to charge the battery.
Q：Why the product is marked of mWh rather than mAh?
A：mWh represents “milliwatt hour”, on behalf of the battery capacity. It is labelled in accordance with the new labeling specifications of lithium-ion batteries. mWh = mAh * voltage.
Q：What is the difference between lithium iron phosphate battery and universal polymer lithium battery?
A：The differences lie in:
1) Voltage: the voltage of lithium iron phosphate battery is 3.2 V. When fully charged, its actual voltage is 3.6 V or so. Such a high voltage is beyond the limit voltage of the appliances using AA or AAA universal battery. So it is easy to damage the appliances (note: this is why the businessman has repeatedly remind users that the battery fully charged should be placed more than 1 hour until the voltage drop, then they can use); universal lithium battery uses intelligent voltage transformation technology, with the constant voltage output voltage of 1.5 V, to ensure the standard voltage of the appliances. (You can check the input voltage parameters on the labels of electrical appliances) Note: the use of this product is like the use of ordinary dry batteries, don’t need to add another bit bucket!
2) Security: Strictly speaking, lithium iron phosphate battery cannot be considered as “batteries”, it is just a cell, without protection circuit; uinversal lithium battery uses multiple intelligence protection circuit preventing overcharge, over discharge, short circuit, overheating, very safe to use. This is also a reason why the cost of the product is higher. Note: lithium iron phosphate battery, because of no protection circuit, have been over discharged when many electrical equipment reach the lowest limit voltage. This is why businesses repeatedly remind users that: Do not charge the battery until it is completely discharged!
3) Capacity: generally, the highest capacity of lithium iron phosphate battery is 600mAh. Its nominal voltage is 3.2V, to be used with bit bucket. Take the electrical equipment using two AA batteries for example. Lithium iron phosphate battery: 600mAh * 3.2V * 1 = 1920mWh; Battery: 760mAh * 3.7V * 2 = 5624mWh; it can be seen that the capacity of lithium batteries is nearly three times that of lithium iron phosphate in the practical application.
Q：What is the concept of the product compared with the ordinary disposable batteries?
A：The product uses polymer lithium cells, which can be recycled 500 to 1000 times. The full charged electricity once is equivalent to that of 2 to 5 batteries. It is no exaggeration to say that a universal lithium battery is equivalent to 1000 to 1500 alkaline batteries, 5000 to 6000 ordinary KK batteries. That’s economical and environment-friendly.
Q：Can we charge other common rechargeable batteries with the special lithium battery’s charger? Or charge universal lithium batteries with ordinary NiMH battery’s charger?
A：No, you can’t! Because charging voltage is different, lithium battery charger is much more complex.
Q：How many mAh is the AA/PH5 battery of 2800 mWh equivalent to?
A：As this is a lithium polymer battery with nominal voltage of 3.7V, and batteries capacity of 760 mAh, when the voltage is converted into the output voltage of 1.5V, it will be more accurate to calculate in “mWh” (power) according to the latest national labelling standard. But compared with the nickel-metal hydride battery, when 1.2 V is divided by 2800 mWh, it is equivalent to more than 2330 mAh. But because the universal lithium is a constant voltage output, the efficient capacity can be released completely, so the stronger battery life of devices using larger electricity reflecting is several times stronger than that of the nickel-metal hydride batteries, or even ten times more.
Q：Is the battery safe?
A：It is very safe, because there are multiple protection mechanism inside the battery. If the voltage conversion circuit is damaged, protection circuit will truncate the output, and the output voltage will be zero.
Q：How about the 1.5 V AA rechargeable lithium battery?
A：Batteries of the AA / AAA rechargeable lithium ion are the best on the universal batteries market, according to the “best” does not mean that the battery manufacturing technology so mystical, but the materials inside the battery – “cells” are changed, used polymer lithium ion cells, while the polymer lithium ion represents the contemporary the most optimal battery technology, so we said the battery is the “best”. , of course, the “best” is relative, lithium batteries due to a high energy, no memory effect, long cycle life, light weight and fast charging itself unique performance advantage has become the mainstream of the current battery power, and all of these “performance advantages of lithium battery is also relative to Ni-MH batteries, we have seen, in the high-end electronic products market is almost can not see the figure of Ni-MH batteries, replaced by lithium batteries; And in the field of general battery, namely we are the most common AA /AAA standard battery system development has been to stay in “nickel metal hydride phase,” battery is precisely at this time, apply a “voltage transformation technology” to “introduction” general batteries, lithium-ion batteries for contemporary general battery and battery technology “synchronous”. We can imagine, with the development of science and technology, technology updates, there may be a fuel cell in the future, better batteries energy sources such as nuclear power battery, but in the present stage of batteries, lithium batteries will occupy the mainstream market in a long time.
What Is the Biologic Fate of Nitrates and Nitrites in the Body?
Exposure to nitrates and nitrites may come from both internal nitrate production and external sources.
Intake of some amount of nitrates is a normal part of the nitrogen cycle in humans.
The mean intake of nitrate per person in the United States is about 40–100 milligrams per day (mg/day) (in Europe it is about 50–140 mg/day).
Nitrate can be synthesized endogenously from nitric oxide (especially in the case of inflammation), which reacts to form nitrite.
Nitrite and nitric oxide can be produced and utilized from exogenous and endogenous sources.
Absorption Nitrates and Nitrites
In the proximal small intestine, nitrate is rapidly and almost completely absorbed (bioavailability at least 92%).
Inorganic nitrate/nitrite can be absorbed via inhalation.
Inorganic nitrate/nitrite does not undergo first pass metabolism.
Distribution Nitrates and Nitrites
Inorganic nitrates/nitrites are distributed widely through the circulation with approximately 25% of absorbed nitrate concentrating in the salivary glands.
Salivary, plasma, and urinary levels of nitrate and then nitrite rise abruptly after ingestion.
An increase in inorganic nitrite levels peaks around 3 hours post ingestion and can be detected about an hour after ingestion.
Metabolism of Inorganic Nitrates and Nitrites
The two main metabolic pathways for inorganic nitrates / nitrites are
The nitrate-nitrite-NO pathway (Figure 1) and
Enterosalivary circulation pathway (nitrate reductase activity of bacteria on the tongue generates nitrite and nitrite which is metabolized to NO in the stomach and circulation).
Approximately 5%–10% of the total nitrate intake is converted to nitrite by bacteria in the saliva, stomach, and small intestine.
In vivo conversion of nitrates to nitrites significantly enhances nitrates’ toxic potency.
This reaction is pH dependent, with no nitrate reduction occurring below pH 4 or above pH 9.
The high pH of the infant gastrointestinal system makes them more susceptible to nitrite toxicity from elevated nitrate/nitrite ingestion.
The metabolic pathway of plasma and tissue nitrates depends on local conditions such as tissue oxygenation, and inflammatory state. In the skin, local conditions also include ultraviolet light exposure.
Nitrate can be reduced to nitrite and nitric oxide when needed physiologically or as part of pathological processes (see Figure 1).
Mammalian metalloproteins and enzymes that have nitrate reductase activity include aldehyde oxidase, heme proteins, mitochondria and xanthine reductase.
The reaction of nitrite with endogenous molecules to form N-nitroso compounds may have toxic or carcinogenic effects.
Excretion Nitrates and Nitrites
Approximately 60% to 70% of an ingested nitrate dose is excreted in urine within the first 24 hours.
About 25% is excreted in saliva through an active blood nitrate transport system and potentially is reabsorbed.
Half-lives of parent nitrate compounds are usually less than 1 hour; half-lives of metabolites range from 1 hour to 8 hours.
In the Fourth National Report on Human Exposure to Environmental Chemicals, urinary levels of nitrate were measured in a subsample of the National Health and Nutrition Examination Survey (NHANES) consisting of participants aged 6 years and older during 2007-2008. The geometric mean for urinary nitrate (in mg/g of creatinine) for the US population aged 6 years and older during 2007-2008 was 47.7, with a 95% confidence interval of 45.9-49.7. Note that these measurements are used in population based public health research and not intended for clinical decision making on individual patients.
Key Points the Biologic Fate of Nitrates and Nitrites in the Body
Exposure to nitrate and nitrites may come from both internal nitrate production and external sources.
Intake of some amount of nitrates is a normal part of the nitrogen cycle in humans.
Nitrate can be reduced to nitrite and nitric oxide when needed physiologically or as part of pathological processes depending on local conditions such as inflammation and tissue oxygenation.
In vivo conversion of nitrates to nitrites significantly enhances nitrates’ toxic potency.
Approximately 5%–10% of the total nitrate intake is converted to nitrite by bacteria in the saliva, stomach, and small intestine.
60-70% of an ingested nitrate dose is excreted in urine within 24 hours.
During deep sleep, cerebrum cleans what it doesn’t need, study finds
During deep sleep, the brain may be tidying up the detritus that accumulates during a hard day of thinking, a recent study suggests.
Researchers have found that during slow-wave sleep in particular – the type of slumber sandwiched between periods of dreaming – a sort of cleaning fluid pulses into the brain, taking out the trash as it recedes, according to a report published in Science.
Using high-speed brain imaging, the researchers were able to map out a series of events that occur as the brain enters deep sleep and brain waves start to slow and synchronize.
They found that the blood flow to the brain diminishes, allowing for an influx of clear, colourless cerebrospinal fluid (CSF). That fluid surges in and sloshes around, washing away the day’s detritus of proteins and other waste substances that might harm the brain if they aren’t cleared out.
“We haven’t ever seen CSF waves on this scale in the awake brain, suggesting that sleep involves a unique pattern of fluid flow in the brain,” said Laura Lewis, an assistant professor of biomedical engineering at Boston University and the study’s senior author.
“Previous studies in animals from other labs have shown that during sleep, proteins such as beta-amyloid (one of two hallmark proteins implicated in Alzheimer’s disease) are cleared more rapidly from the brain,” Lewis said. “Based on these studies; we wondered why this might occur and we wanted to ask whether CSF changes during sleep because CSF is thought to be important for waste removal.”
Lewis and her colleagues suspect that poor sleep in patients with neurological disorders might impact the tidying up process, leaving waste materials to accumulate, eventually leading to degeneration.
“We’re running new studies to test how these CSF waves may change in healthy aging and in neurological disorders,” she said. “We’re also going to test whether this would be associated with less waste removal from the brain during sleep in these patients.”
The new research shows how the rhythmic flow of fluid during deep sleep could be the way the brain washes away waste, Danish researchers write in a commentary that accompanied the new study.
Understanding that process might shed a light on how disturbed sleep could be linked to certain neurologic disorders, write Soren Grubb, an assistant professor in the department of neuroscience at the University of Copenhagen, and Martin Lauritzen, a professor of clinical neurophysiology at Rigshospitalet.
“Disturbances of (slow wave sleep) commonly accompany aging, major depressive disorders and dementia,” they note.
“It will be interesting to assess whether the CSF dynamics linked to SWS can be used as a biomarker for disease states and whether strategies to restore SWS can rescue brain function in neurodegeneration.”