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Your unique smell can provide clues about how healthy you are

<p><em><a href="https://theconversation.com/profiles/aoife-morrin-1478132">Aoife Morrin</a>, <a href="https://theconversation.com/institutions/dublin-city-university-1528">Dublin City University</a></em></p> <p>Hundreds of chemicals stream from our bodies into the air every second. These chemicals release into the air easily as they have high vapour pressures, meaning they boil and turn into gases at room temperature. They give clues about who we are, and how healthy we are.</p> <p>Since ancient Greek times, we’ve known that we smell differently when we are unwell. While we rely on blood analysis today, ancient Greek physicians used smell to diagnose maladies. If they took a whiff of your breath and described it as <em>fetor hepaticus</em> (meaning bad liver), it meant you could be headed for liver failure.</p> <p>If a person’s whiff was sweet or fruity, physicians thought this meant that sugars in the digestive system were not being broken down, and that person had probably diabetes. Science has since shown the ancient Greeks were right – liver failure and <a href="https://tisserandinstitute.org/human-volatilome/">diabetes</a> and many <a href="https://link.springer.com/article/10.1007/s00216-023-04986-z">other diseases</a> including infectious diseases give your breath a distinctive smell.</p> <p>In 1971, <a href="https://www.nobelprize.org/prizes/peace/1962/pauling/facts/">Nobel Laureate chemist Linus Pauling</a> <a href="https://edu.rsc.org/feature/breath-analysis/2020106.article#:%7E:text=The%20'modern%20era'%20of%20breath,in%20an%20average%20breath%20sample.">counted 250 different</a> gaseous chemicals in breath. These gaseous chemicals are called volatile organic compounds or VOCs.</p> <figure><iframe src="https://www.youtube.com/embed/RzozmYPfCmM?wmode=transparent&amp;start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe></figure> <p>Since Pauling’s discovery, other scientists have <a href="https://link.springer.com/article/10.1007/s40291-023-00640-7">discovered hundreds more VOCs</a> in our breath. We have learned that many of these VOCs have distinctive odours, but some have no odour that our noses can perceive.</p> <p>Scientists believe that whether a VOC <a href="https://tisserandinstitute.org/human-volatilome/">has an odour</a> that our noses can detect or not, they can reveal information about how healthy someone is.</p> <p>A Scottish man’s Parkinson’s disease onset was <a href="https://www.bbc.co.uk/news/uk-scotland-47627179">identified by his wife</a>, retired nurse Joy Milner, after she was convinced the way he smelled had changed, years before he was diagnosed in 2005. This discovery has <a href="https://www.manchester.ac.uk/discover/news/smell-of-skin-could-lead-to-early-diagnosis-for-parkinsons/">led to research programmes</a> involving Joy Milner to identify <a href="https://www.scientificamerican.com/article/a-supersmeller-can-detect-the-scent-of-parkinsons-leading-to-an-experimental-test-for-the-illness/">the precise smell</a> of this disease.</p> <p>Dogs can <a href="https://www.nature.com/articles/d41586-022-01629-8">sniff out more diseases</a> than humans because of their more <a href="https://www.understandinganimalresearch.org.uk/news/the-science-of-sniffs-disease-smelling-dogs%20-%20I%20think%20the%20previous%20nature%20link%20has%20more%20credibility%20for%20here%20also">sophisticated olfactory talents</a>. But technological techniques, like <a href="https://www.britannica.com/science/mass-spectrometry">analytical tool mass spectrometry</a>, picks up even more subtle changes in VOC profiles that are being linked to <a href="https://www.thelancet.com/journals/ebiom/article/PIIS2352-3964(20)30100-6/fulltext">gut</a>, <a href="https://www-sciencedirect-com.dcu.idm.oclc.org/science/article/pii/S0165993618305168">skin</a> and <a href="https://err.ersjournals.com/content/28/152/190011">respiratory</a> diseases as well as neurological diseases like Parkinson’s. Researchers believe that one day some diseases will be diagnosed simply by breathing into a device.</p> <figure><iframe src="https://www.youtube.com/embed/Xjo2M-XMYfs?wmode=transparent&amp;start=0" width="440" height="260" frameborder="0" allowfullscreen="allowfullscreen"></iframe></figure> <h2>Where do VOCs come from?</h2> <p>Breath is not the only source of VOCs in the body. They are also emitted from skin, urine and faeces.</p> <p>VOCs from skin are the result of millions of skin glands removing metabolic waste from the body, as well as waste generated by bacteria and other microbes that live on our skin. Sweating produces extra nutrients for these bacteria to metabolise which can result in particularly odorous VOCs. Odour from sweat only makes up a fraction of the scents from VOCs though.</p> <p><a href="https://www.nature.com/articles/nrmicro.2017.157">Our skin</a> and also our gut microbiomes are made up from a delicate balance of these microbes. Scientists think <a href="https://journals.lww.com/co-gastroenterology/abstract/2015/01000/the_gut_microbiome_in_health_and_in_disease.12.aspx">they influence our health</a>, but we don’t yet understand a lot about how this relationship works.</p> <p>Unlike the gut, the skin is relatively easy to study – you can collect skin samples from living humans without having to go deep into the body. <a href="https://www-sciencedirect-com.dcu.idm.oclc.org/science/article/pii/S1471492221002087">Scientists think</a> skin VOCs can offer insights into how the microbiome’s bacteria and the human body work together to maintain our health and protect us from disease.</p> <p>In my team’s laboratory, <a href="https://iopscience.iop.org/article/10.1088/1752-7163/abf20a">we are investigating</a> whether the skin VOC signature can reveal different attributes of the person it belongs to. These signals in skin VOC signatures are probably how dogs distinguish between people by smell.</p> <p>We are at a relatively early stage in this research area but we have shown that you can tell males from females based on how acidic the VOCs from skin are. We use mass spectrometry to see this as the average human nose is not sophisticated enough to detect these VOCs.</p> <p>We can also predict a person’s age with reasonable accuracy to within a few years from their skin VOC profile. This is not surprising considering that oxidative stress in our bodies increases as we age.</p> <p><a href="https://www.metabolismjournal.com/article/S0026-0495(00)80077-3/pdf">Oxidative stress</a> happens when your antioxidant levels are low and causes irreversible damage to our cells and organs. <a href="https://pubs.acs.org/doi/10.1021/jasms.3c00315">Our recent research</a> found by-products of this oxidative damage in skin VOC profiles.</p> <p>Not only are these VOCs responsible for personal scent – they are used by plants, insects and animals as a communication channel. Plants are in a <a href="https://www.nature.com/articles/s41598-017-10975-x">constant VOC dialogue</a> with other organisms including pollinators, herbivores, other plants and their natural enemies such as harmful bacteria and insects. VOCs used for this back and forth dialogue are known as pheromones.</p> <h2>What has science shown about love pheromones?</h2> <p>In the animal kingdom, there is good evidence VOCs can act as aphrodisiacs. Mice for example have microbes which contribute to a particularly <a href="https://www.sciencedirect.com/science/article/pii/S0960982212012687">smelly compound called trimethylamine</a>, which allows mice to verify the species of a potential mate. <a href="https://www.sciencedirect.com/science/article/abs/pii/S0093691X21003083">Pigs</a> and <a href="https://www.nature.com/articles/4381097a">elephants</a> have sex pheromones too.</p> <p>It is possible that humans also produce VOCs for attracting the perfect mate. Scientists have yet to fully decode skin – or other VOCs that are released from our bodies. But evidence for human love pheromones so far is <a href="https://www.science.org/content/article/do-human-pheromones-actually-exist">controversial at best</a>. <a href="https://www.newscientist.com/article/dn3835-colour-vision-ended-human-pheromone-use/">One theory suggests</a> that they were lost about 23 million years ago when primates developed full colour vision and started relying on their enhanced vision to choose a mate.</p> <p>However, we believe that whether human pheromones exist or not, skin VOCs can reveal who and how we are, in terms of things like ageing, nutrition and fitness, fertility and even stress levels. This signature probably contains markers we can use to monitor our health and diagnose disease.<!-- Below is The Conversation's page counter tag. 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More info: https://theconversation.com/republishing-guidelines --></p> <p><a href="https://theconversation.com/profiles/aoife-morrin-1478132"><em>Aoife Morrin</em></a><em>, Associate Professor of Analytical Chemistry, <a href="https://theconversation.com/institutions/dublin-city-university-1528">Dublin City University</a></em></p> <p><em>Image credits: </em><em>Getty Images </em></p> <p><em>This article is republished from <a href="https://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/your-unique-smell-can-provide-clues-about-how-healthy-you-are-215311">original article</a>.</em></p>

Body

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Perfect perfume or eau de cat’s bum? Why scents smell different and 4 fragrance tips

<p>Mother’s Day is coming up in Australia and that means a surge in perfume sales. Of course, scents are purchased year-round and not just for mothers. Fragrance sales in Australia will amount to <a href="https://www.statista.com/outlook/cmo/beauty-personal-care/fragrances/australia%5D">over A$1 billion</a> this year.</p> <p>The word “perfume” is derived from the Latin per fumus, meaning “through smoke”. The <a href="https://www.amazon.com/Mendeleyevs-Dream-Elements-Paul-Strathern/dp/0312262043">very first account</a> of using perfumes dates back to 1200 BC when a <a href="https://books.google.com.au/books/about/Women_of_Science.html?id=S7DaAAAAMAAJ&amp;redir_esc=y">woman called Tapputi</a> mixed flowers, oils and various plants with water or solvents, then extracted their fragrance. The basis of this technique for making perfume is still used today.</p> <p>But how do we smell? What makes perfume appealing? And why does it smell differently on different people?</p> <h2>The science of smell</h2> <p>A sense of smell is vital to all species on Earth. One <a href="https://www.science.org/content/article/elephants-may-have-best-noses-earth">study</a> identified African elephants as having the “best noses” in the animal kingdom, not to mention the longest ones. It can help animals sniff out danger, food and mates.</p> <p>For humans, too, being able to smell is not just for the enjoyment of pleasant odours. It can also protect us from toxic chemicals with noxious smells, such as <a href="https://www.cdc.gov/niosh/ershdb/emergencyresponsecard_29750038.html#:%7E:text=Hydrogen%20cyanide%20(AC)%20gas%20has,as%20a%20solution%20in%20water.">hydrogen cyanide</a>.</p> <p>When something has an odour, it means it is chemically volatile – vaporising from a liquid to a gas. When we smell a scent, gas molecules enter our nose and stimulate specialised nerve cells called <a href="https://theconversation.com/curious-kids-how-do-we-smell-104772">olfactory sensory neurons</a>. When these neurons are triggered, they send a signal to the brain to identify the chemicals.</p> <p>Humans have around 10 million of those neurons and around <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1905909/">400 scent receptors</a>. The human nose can distinguish at least <a href="https://www.science.org/content/article/human-nose-can-detect-trillion-smells#:%7E:text=These%20are%20only%20three%20of,never%20been%20explicitly%20tested%20before.">1 trillion different odours</a>, from freshly brewed coffee to wet dog to mouldy cheese.</p> <p>The more volatile a compound is the lower its boiling point and, from a chemical perspective, the weaker the forces holding the molecules together. When this is the case, more molecules enter the gaseous state and the smell is more intense.</p> <h2>What makes things smell good though?</h2> <p>Different classes of chemical compounds can have more pleasant or offensive scents.</p> <p>Fish and decaying animal cells, for example, release chemicals called <a href="https://chem.libretexts.org/Courses/BridgeValley_Community_and_Technical_College/Fundamentals_of_Chemistry/11%3A_Organic_Chemistry/11.15%3A_Amines#:%7E:text=Amines%20generally%20have%20rather%20pungent,odor%20associated%20with%20dead%20fish.">amines</a>, which don’t smell appealing.</p> <p>Fruits, on the other hand, are composed of chemicals in a class of organic compounds called aldehydes, esters and ketones, which have sweeter and <a href="https://chem.libretexts.org/Courses/Sacramento_City_College/SCC%3A_CHEM_330_-_Adventures_in_Chemistry_(Alviar-Agnew)/09%3A_Organic_Chemistry/9.08%3A_Carboxylic_Acids_and_Esters#:%7E:text=Esters%20occur%20widely%20in%20nature,fragrances%20of%20fruits%20and%20flowers.">more pleasant odours</a>.</p> <p>Chemists have been able to identify the <a href="https://jameskennedymonash.wordpress.com/2014/01/04/table-of-organic-compounds-and-their-smells-revised-edition/">specific chemical smells</a> released by substances we encounter in everyday life.</p> <h2>Smells different</h2> <p>So it makes sense that pleasant-smelling aldehydes, ketones and esters are used to create perfumes. However, some perfumes also contain unusual ingredients that don’t smell nice on their own.</p> <p>For example, Chanel No. 5 perfume – the iconic 100-year-old favourite – contains civet as one of its base chemical notes. <a href="https://www.nytimes.com/1973/04/15/archives/a-boycott-of-chanel-no-5-urged-by-humane-groups.html">Civet</a> is used by perfumers for its <a href="https://theconversation.com/civet-musk-a-precious-perfume-ingredient-is-under-threat-steps-to-support-ethiopian-producers-and-protect-the-animals-193469">long-lasting, musky scent</a>. It is traditionally extracted from the anal glands of <a href="https://slate.com/technology/2012/07/chanel-no-5-a-brain-parasite-may-be-the-secret-to-the-famous-perfume.html">civet cats</a> but Chanel has used a synthetic form of civet <a href="https://www.ft.com/content/99a13235-cdb9-431b-b8f1-e52ce4a10486">since 1998</a>.</p> <h2>Tips for choosing and using perfumes</h2> <p>Our ability to smell a perfume will depend on two factors: how well our olfactory sensory neurons are performing (a virus or infection could affect function, for example) and the volatility of the chemicals in the perfume.</p> <p>1. Try before you buy</p> <p>You can’t really do much about your sensory neurons, but you can increase the intensity of perfumes, such as by warming up the perfume on your skin or applying to pulse points. This will help to give molecules more energy and increase the number of molecules entering the gaseous state.</p> <p>Specific perfumes will not smell the same on different people’s skin because the chemicals in them can be affected by the skin’s type and condition (dry or oily, acidic or base) and even their diet. Some foods we eat, such as garlic, are released from our bodies through our skin. Those chemicals can mask perfume chemicals.</p> <p>So, it is better to buy someone their tried and true favourite scent rather than risking a new one. And those department store sample sprays can be useful to try before you buy.</p> <p>2. Moisturise before use</p> <p>When you spray perfume on very dry skin, some of the perfume’s chemicals – the large organic ones that are similar to skin’s natural oils – are absorbed by the skin and then into the sebaceous glands. When some notes in a perfume are absorbed this way, it can take on a different smell. That’s also why it’s better to moisturise skin before spraying perfume, so perfume chemicals stay on the skin for longer.</p> <p>3. Experiment with spraying techniques</p> <p>To avoid changes in the scent of your favourite perfume and increase the time the perfume stays on you, you could spray your hair instead. Your hair is porous so perfume molecules might remain there longer. However, most perfumes contain alcohol, which dries out hair. Spraying perfume directly onto a hairbrush first, then brushing your hair, might prevent some of this drying effect.</p> <p><a href="https://www.byrdie.com/how-to-apply-perfume">Spraying then walking</a> through a mist of perfume so the chemicals settle on your hair, skin and clothes might work – but you risk losing a lot of precious perfume with that technique.</p> <p>4. Keep it cool</p> <p>Temperature will <a href="https://www.researchgate.net/publication/5674095_Effect_of_Temperature_on_the_Floral_Scent_Emission_and_Endogenous_Volatile_Profile_of_Petunia_axillaris">affect volatility</a>. To keep perfumes lasting longer in the bottle, keep them in the fridge or cool dark place and tightly sealed to prevent your expensive, heat-sensitive scent evaporating into thin air.</p> <p><em>This article originally appeared on <a href="https://theconversation.com/perfect-perfume-or-eau-de-cats-bum-why-scents-smell-different-and-4-fragrance-tips-203905" target="_blank" rel="noopener">The Conversation</a>.</em></p> <p><em>Images: Getty</em></p>

Beauty & Style

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7 natural ways to make your home smell better

<p>Nothing makes us feel more productive than whipping out our scrubs and subjecting our home to a deep cleansing session. Conversely, nothing makes us feel unhealthier than breathing in the chemical-laden scents that seem to linger for days. While cleaning often is paramount to maintaining a germ-free home, these harsh cleaning products can be hazardous to your health and also leave your home smelling like a hand sanitiser rather than a comfortable environment.</p> <p>It’s time to deodorise your home the right way to make it fresh for entertaining guests. That’s why we’ve concocted a few natural formulas below that will not only leave your home clean but smelling sweet.</p> <p><strong>1. Cutting board</strong></p> <p>You’re likely aware of the all-purpose benefits of coconut oil, but what you might not know is that it has natural antibacterial properties, making it the perfect ingredient to introduce into your cleaning routine. If you own a wooden cutting board, you know they require a bit more care. Not only should you regularly clean and sanitise it, but you’ll need to condition the wood at least once a month to keep it from cracking.</p> <p>They’ll also hold up longer and harbor less germs with a regular cleanse, which can be accomplished with coconut oil. First, spray your board with a little vinegar before washing well with warm soapy water. Once dry, gently massage coconut oil into the wood to condition the cutting board and leave it with a shiny finish.</p> <p><strong>2. Microwave</strong></p> <p>If you rely on your microwave to heat leftovers, the mix of aromas from various cuisines can create quite a stench. The stale air from the small, enclosed space in the machine doesn’t help either. Fortunately, deodorising it is incredibly easy. Fill a microwave-safe bowl halfway with water, and squeeze in one whole lemon. Heat the bowl in the microwave for five minutes, and then let it sit for a couple of minutes to cool. When you open the door, you’ll be met with a clean, fresh scent.</p> <p><strong>3. Garbage disposal</strong></p> <p>Your garbage disposal can be a deep, dark, scary place. It can also smell pretty horrific after mixing up a bad combination of old food. Get rid of offensive scents by tossing two cups of ice and one cup of salt down a clear disposal and run it with cold water. The ice, salt and water will negate the smell, but if you want to leave a fresh scent, follow this combo up by running it again with half a lemon.</p> <p><strong>4. Cookware</strong></p> <p>Even if you wash your pots and pans regularly with dish soap, they could still use an extra deep-clean in between meals to remove the buildup of excess grease and grime. This natural combo will clean, sanitise and deodorise your cookware and cutting boards with just two ingredients. First, squeeze the juice from one half of a lemon onto the surface; then sprinkle with a generous amount of coarse sea salt, and squeeze the second half of the lemon on top.</p> <p>Use the halved lemons as your sponges to scrub the salt into the board. Finish by removing the salt with damp paper towels. The lemon removes the potent scents of garlic and onions, and the salt works to sanitise the surface.</p> <p><strong>5. Glass and mirrors</strong></p> <p>Before there was Windex, there was vinegar. This throwback trick works just as well now to create a crystal-clear, smudge-free reflection in your glasses and mirrors. Simply mix distilled water with white vinegar in equal parts. While there’s vinegar specifically created for cleaning, you can also use a white vinegar from your cooking cabinet. If you’re not a big fan of the strong vinegar scent, mix in a couple drops of your favourite essential oil (we’re big fans of lavender) to dilute the sourness. Wipe down your windows and glass surfaces with a lint-free cloth for exceptional shine.</p> <p><strong>6. Oven</strong></p> <p>While cleaning out your oven might feel like an enormous feat, it’s imperative to make sure you don’t leave old food or grease laying around in fear of bad odours, or worse, a grease fire. Spritz your oven with water to wet (but not soak) the surface; then coat with baking soda to make a paste. Close the door and leave the paste on overnight or for a few hours during the day. Then scrub out all of the baking soda with some water. The paste will turn brown from all the grease and grime.</p> <p>Be sure to wipe off all of the baking soda before using the oven. You can also top it off with a vinegar-water mix from before to add extra shine.</p> <p><strong>7. Bathroom</strong></p> <p>The bathroom is a cleaner’s worst nightmare due to the endless list of places to clean – the tiles, the tub, the toilet, oh my! But just a few simple formulas can have the room spick-and-span. A sprinkle of baking soda mixed with water will take on tough stains on grout.</p> <p>Baking soda can also be used to freshen, clean, and sanitise the toilet: Coat the bowl, and scrub with a mixture of vinegar diluted with water. To tackle the tub, shower, and sink, use the 50/50 water and vinegar solution (mixed with essential oils if you prefer a sweeter scent) to remove scum from soap and shampoo.</p> <p>Do you have a nifty trick for keeping your home smelling great that you would like to share with us? Let us know in the comments below.</p> <p><em>Written by Meghan Rooney. First appeared on <strong><a href="http://www.domain.com.au/" target="_blank" rel="noopener"><span style="text-decoration: underline;">Domain.com.au.</span></a></strong></em></p> <p><em>Image: Getty</em></p>

Home Hints & Tips

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A history of head injuries could impact your sense of smell

<p dir="ltr">A history of head injuries could make you more likely to experience a loss of your sense of smell, according to a team of international researchers.</p> <p dir="ltr">The study, published in the journal <em><a href="https://doi.org/10.1001/jamaoto.2022.1920" target="_blank" rel="noopener">JAMA Otolaryngology-Head &amp; Neck Surgery</a></em>, found that out of 5,961 participants - including 1,666 people who had a history of head injuries - those who had suffered from at least two head injuries or had more severe injuries were more likely to report a loss of smell.</p> <p dir="ltr">If you’ve ever had a nose full of snot during a severe cold or sinus infection, you’ve likely experienced a temoorary bout of anosmia - a full or partial loss of your sense of smell - but it can also be permanent.</p> <p dir="ltr">The team reported that 24 percent of those with a history of head injuries self-reported a loss of smell, in comparison to 20 percent of those with no head injuries, with 15 percent having objective anosmia versus 13 percent in the cohort with no injuries.</p> <p dir="ltr">For those with traumatic brain injuries (TBI), previous studies have found that 14 to 20 percent suffer from a loss of smell, with this most-recent study finding that the likelihood of suffering from smell loss relied on both the number of head injuries and their severity.</p> <p dir="ltr">The researchers found that both self-reporting a loss of smell and being objectively assessed to have anosmia were associated with a person having a history of at least two head injuries which were moderate, severe or penetrating.</p> <p dir="ltr">As for how TBIs cause a loss of smell, the authors suggest that it could include the shearing of the olfactory nerve fibres anchored to the cribriform plate, a part of the ethmoid bone that is anchored in the nasal cavity that is covered in holes to allow for nerves to convey smells to the brain.</p> <p dir="ltr">They also suggest that injuries to the sinonasal tract, olfactory bulbs, and olfactory-eloquent cortical brain regions could be behind smell loss, but note that other factors such as severe depression, posttraumatic epilepsy, and medications prescribed to manage TBIs could be responsible.</p> <p dir="ltr">Surprisingly, the team reported that a high proportion of participants were unaware of the extent of their loss of smell, echoing findings from previous studies.</p> <p dir="ltr">They found that those with a history of head injuries were more likely to under-report or over-report the extent of their smell loss - which was also measured using objective olfactory testing - in comparison to those who hadn’t suffered a head injury.</p> <p dir="ltr">Given that a loss of smell is often inaccurately reported by those with head injuries and that it is associated with negative effects on mental and physical health, the team argue that their study has important considerations for health practitioners working with patients with a history of head injuries.</p> <p dir="ltr">“Findings also suggest important clinical considerations for the diagnosis and treatment of posttraumatic olfactory loss; that individuals with remote prior head injury are at risk for posttraumatic olfactory dysfunction but are unlikely to be aware of their deficits; and conversely, that individuals with prior head injury may be more likely to overreport subjective olfactory deficits, which may not be confirmed by objective testing,” they write.</p> <p dir="ltr">“Taken together, there should be consideration of objective psychophysical olfactory assessment in patients with head injury.”</p> <p><span id="docs-internal-guid-3fa7b9f3-7fff-41af-93ce-6d8988e762d4"></span></p> <p dir="ltr"><em>Image: Getty Images</em></p>

Mind

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When a smell evokes a memory

<p>In an episode of the popular TV series Black Mirror called <a rel="noopener" href="https://www.vox.com/culture/2017/12/29/16808458/black-mirror-crocodile-recap-season-4-review" target="_blank">Crocodile</a>, an investigator asks a witness to smell a bottle of beer. The aim is to refresh her memory of a crime scene (the crime took place near a brewery).</p> <p>This might not exactly be standard practice, but our sense of smell, or olfaction, is known for its ability to elicit memories. We all know the feeling. A whiff of a particular scent can take you back to your grandmother’s kitchen, the night of your first dance, or the sea shore.</p> <p>And think of “scent marketing”, where brand designers infuse “signature scents”, for example in fashion stores and hotel lobbies, to enhance brand recognition across the globe.</p> <p>Neuroscientists studying olfaction have long wondered about <a rel="noopener" href="https://doi.org/10.1016/s0166-2236(03)00076-6" target="_blank">the connection</a> between our sense of smell and memory. Is this relationship between memory and olfaction a result of the way the brain is wired? A study recently published in the journal <em><a rel="noopener" href="https://www.nature.com/articles/s41586-021-04242-3" target="_blank">Nature</a></em> has broken important ground towards answering this longstanding question.</p> <p>Before we look at the study, some background about how the brain facilitates our sense of smell. Scent molecules are initially detected by receptor neurons in the nose. The neurons send information about these encounters first to the <a rel="noopener" href="https://www.britannica.com/science/olfactory-bulb" target="_blank">olfactory bulb</a>, a brain structure about the size of your fingertip located above the nasal cavity.</p> <p>The olfactory bulb then sends signals to another brain structure called the <a rel="noopener" href="https://www.sciencedirect.com/topics/neuroscience/piriform-cortex" target="_blank">piriformk cortex</a>. It is believed odour recognition happens there – that is, we identify its potential source, like an apple, a banana, or freshly cut grass.</p> <p><strong>What the researchers did</strong></p> <p>To study how the brain combines olfactory and spatial information, Cindy Poo and her colleagues at the Champalimaud Centre for the Unknown in Portugal had six rats complete a navigation task.</p> <p>The rats had to repeatedly navigate a cross-shaped map with four corridors, as shown in the video below from about the two-and-a-half minute mark. At the beginning of each trial a light would point the rat down one of the corridors, where it would be exposed at random to one of four distinct smells (citrus, grass, banana or vinegar). The location of a water reward was dependent on which odour the rat was exposed to.</p> <p>For example, the citrus odour meant the water reward was at the end of the south corridor. If the rat was exposed to the citrus smell in the east corridor, it would need to travel south for the reward. If it received the smell in the south corridor in the first instance, it could stay put and receive the reward. The idea was that with practice, a given smell would signal to the rat the location of the reward.</p> <p><iframe width="440" height="260" src="https://www.youtube.com/embed/BunEBiU3MO0?wmode=transparent&amp;start=0" frameborder="0" allowfullscreen=""></iframe></p> <p>The surroundings of the maze were decorated with visual landmarks so the rats could also orientate themselves based on those landmarks. However, the rats’ starting point was different in each trial. If it had been fixed, they could theoretically just have memorised a sequence of turns to find the correct corridor, and not used any spatial memory at all. This meant that completing the task successfully relied on a combination of spatial navigation and olfaction.</p> <p>After about three weeks of training the rats did quite well; they were able to locate the water reward in roughly 70% of trials. This indicates that the rats were able to combine their internal map of the environment with locations of smells to locate the reward.</p> <p><strong>Looking at neuron activity</strong></p> <p>Neurons in the hippocampus, a part of the brain involved in memory and navigation, are known for functioning as “place cells”. These are cells which <a rel="noopener" href="https://www.nobelprize.org/prizes/medicine/2014/summary/" target="_blank">become active</a> at a specific location in an environment, which allows us to find our way around. Similar cells are also found in another part of the brain called the entorhinal cortex.</p> <p>The most striking finding of the new study is that such location-selective cells are not only present in the hippocampus and entorhinal cortex, but also in a brain area linked primarily to olfactory function, namely the piriform cortex, the place thought to be primarily responsible for odour recognition.</p> <p>The researchers in the study monitored the electrical activity of neurons in this area. Surprisingly, they found that only around 30% of neurons in this region of the rats’ brains responded to specific odours. Another 30% of neurons fired in response to both a particular smell and location.</p> <p>The remaining 40% of active neurons did not respond to specific odours at all, but rather to the locations where the rats had previously smelt the odours. These location-selective neurons would even start to fire when the rats were only just entering the corridor, before encountering any smell.</p> <p>The researchers then wanted to understand whether the hippocampus and piriform cortex “talked” to each other while the rats were solving the puzzle. They found that cells in both regions tended to fire in synchrony while the rats were navigating the maze.</p> <p><strong>So what does this tell us?</strong></p> <p>These results show that the olfactory system may play a role in spatial navigation, and that spatial memory and olfactory information converge in the piriform cortex. But why has the brain evolved to represent location and odour in the same area?</p> <p>The answer could be that odours are very useful clues for finding our way around. For example, a pine forest smells different from a meadow, while a fox’s burrow has a different smell to a rat’s nest. The rule holds even in man-made environments: an underground rail system smells different from a supermarket, an office different from a restaurant.</p> <p>So our brains might be wired to associate smells with places because this has been useful in our evolutionary past.</p> <p>This study was conducted in rats, which rely more on their sense of smell for navigation than humans do, since our perception is dominated by vision. But these findings do give new insights about how olfaction and spatial memory are likely connected in the human brain.<!-- Below is The Conversation's page counter tag. Please DO NOT REMOVE. --><img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important; text-shadow: none !important;" src="https://counter.theconversation.com/content/174477/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /><!-- End of code. If you don't see any code above, please get new code from the Advanced tab after you click the republish button. The page counter does not collect any personal data. More info: https://theconversation.com/republishing-guidelines --></p> <p><em><a rel="noopener" href="https://theconversation.com/profiles/michael-schmuker-175218" target="_blank">Michael Schmuker</a>, Professor of Neural Computation, <a rel="noopener" href="https://theconversation.com/institutions/university-of-hertfordshire-799" target="_blank">University of Hertfordshire</a></em></p> <p><em>This article is republished from <a rel="noopener" href="https://theconversation.com" target="_blank">The Conversation</a> under a Creative Commons license. Read the <a rel="noopener" href="https://theconversation.com/when-a-smell-evokes-a-memory-new-research-offers-clues-about-how-the-two-are-linked-in-the-brain-174477" target="_blank">original article</a>.</em></p> <p><em>Image: Getty Images</em></p>

Mind

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"That smell!": Permanent portaloo upsets neighbours

<p>NSW Central Coast residents are furious with their neighbour who abandoned a caravan and portaloo five years ago in their suburban street.</p> <p>The caravan is on an overgrown section on the street, but it's the portaloo that infuriates neighbours.</p> <p>"Disgusting, absolutely disgusting," neighbour Kylie Griffith told<span> </span><em>A Current Affair.</em></p> <p>"It looks like a bogan's house, like someone that doesn't care for it."</p> <p>Although things are bad now, they were worse when owner Hervander Bhandari was living there.</p> <p>He submitted plans to build a grand home after buying the site for $135,000 in 2014.</p> <p>"It was five storeys high," neighbour Stephen Crampton said.</p> <p>"The bricks turned up, the portaloo and virtually he was staying in it all the time."</p> <p>Neighbours were disgusted as they watched his personal routine, which included showering with a garden hose.</p> <p>That didn't bother them as much as the smell from the portaloo.</p> <p>"When he flushed the toilet, the water used to come back out of the port skip here and down the roadway, down his block of land into the neighbour's driveway, down the gutter and into the stormwater," Mr Crampton said.</p> <p>"It was disgusting. It was shocking. You would go, 'oh no, not again, that smell'.</p> <p>"We would have to have all our windows up and everything, we couldn't put up with it."</p> <p>Mr Crampton had enough and contacted the Central Coast Council, who instructed him to keep a diary of his movements.</p> <p>After enough evidence, the council took Mr Bhandari to the NSW Land and Environment Court, claiming that his living situation was illegal.</p> <p>Mr Bhandari told the court he has no interest in taking part in the case and it's currently understood that he has moved home to India.</p> <p>The Central Coast Council has said that Mr Bhandari has until January 17th to clean up the site before council moves in.</p> <p>Neighbours are upset at the decision as the council has told them they will only remove the portaloo, which means that the stack of bricks and the caravan will stay on the land.</p> <p>"They need to get rid of that stinking old caravan cause the smell is still here," Mr Crampton said.</p>

Real Estate

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How far away can dogs smell and hear?

<p>Great question Georgina. We know and learn about the world around us through our senses. The senses of smell and hearing in dogs mean they experience a different world to us.</p> <p>Dogs have many more <a href="https://www.frontiersin.org/articles/10.3389/fvets.2018.00056/full">smell receptors than humans</a> – a <a href="https://www.britannica.com/science/olfactory-receptor">receptor</a> is a part of the nose that recognises each unique smell particle.</p> <p>Dogs also have a lot more surface area in their noses and are better at moving air through their noses than us. Watch a dog sniffing and you can see this for yourself. If more air passes through their nose they have more chance to pick up smells.</p> <p>How far dogs can smell depends on many things, such as the wind and the type of scent. Under perfect conditions, they have been <a href="https://www.goodreads.com/book/show/17368247-the-perfect-dog">reported</a> to smell objects or people as far as 20km away.</p> <p>You might be interested to know dogs are not the only great smellers. The scientific family dogs belong to is Carnivora. This includes cats, bears and skunks.</p> <p>These animals have incredible senses of smell as well. Bears have some of the best senses of smell in the family. Polar bears can smell seals, which they hunt, from <a href="https://www.livescience.com/43673-weird-facts-about-polar-bears.html">more than 30km away</a>.</p> <p>How would it feel if you knew just by smell when your best friend was in the next room, even if you couldn’t see them? Wouldn’t you love to know where your parents had hidden your favourite chocolate biscuits in the pantry, just by sniffing them out?</p> <p><strong>Dog the detector</strong></p> <p>This amazing sense of smell means dogs have some of the most interesting jobs of any animal: the detection dog.</p> <p>Detection dogs help <a href="https://www.sarda.net.au/">search and rescue</a> organisations to find missing people, look for dangerous materials such as <a href="https://www.police.wa.gov.au/About-Us/Our-Agency/Specialist-Units/Mounted-and-Canine-Operations/Police-Dog-Squad">drugs and bombs</a>, <a href="https://www.abc.net.au/news/2017-06-10/afp-sniffer-dogs-training-explained/8606228">illegal imports</a> at airports, and help <a href="https://www.lfwseq.org.au/sniffing-solutions-detection-dogs-conservation/">find wild animals</a>.</p> <p>All of it’s done with their noses, which makes dogs some of the best sniffers in the world.</p> <p>One thing that might still puzzle you is why, when dogs have such a great sense of smell, they like to smell things that are disgusting to us, like other dogs’ bottoms. That’s a story for another day.</p> <p><strong>Hear and far</strong></p> <p>Now we know dogs can smell lots of things from far away, what about their hearing? What can dogs hear, and from how far? To find out, first we have to talk about what dogs and all animals (including us) hear: sound frequencies.</p> <p>Sounds have waves. The frequency of sound is how close together the sound waves are. The closer together the waves, the higher the frequency or pitch. You can think of this like the beach during a storm, when waves hit the beach more often.</p> <p>Dogs and people hear about the same at low frequencies of sound (around 20Hz). This changes at high frequencies of sound, where dogs hear up to 70-100kHz, much better than people at only 20kHz. Dogs hear sound frequencies at least three times as high compared to people.</p> <p>You may have wondered how those special silent dog whistles work? They make high-frequency sounds that dogs can hear but we can’t. Because dogs can hear higher frequencies than us, there are a lot more sounds for dogs to hear.</p> <p>They can also hear sounds that are softer or farther away, as far as a kilometre. That means dogs can be more sensitive to loud sounds. This is why <a href="https://positively.com/dog-behavior/behavior-problems/fears-and-phobias/noise-phobias/">some dogs are scared of fireworks or thunderstorms</a>. It is also why a dog might bark at a sound you cannot hear.</p> <p><strong>Prick up your ears</strong></p> <p>Part of how dogs hear so well has to do with their ear muscles. Dogs have more than a dozen muscles that allow them to tilt, lift and rotate each ear independently of one another.</p> <p>This helps dogs locate where sounds come from. It is also part of why dogs may <a href="https://www.petmd.com/dog/behavior/why-do-dogs-tilt-their-heads">tilt their heads</a> to some sounds. Police who use dogs say the first sign their dog has located a suspect is when they see their ears move around to focus on a place.</p> <p>Having great hearing also helps dogs with another one of their interesting jobs: the assistance dog. <a href="https://guidedogsaustralia.com/">Assistance dogs</a> work with people who need help in their daily lives, such as those who are blind or deaf.</p> <p>Excellent hearing means dogs can identify people arriving at a home or oncoming traffic at a walkway. With such great hearing, dogs can help people in need navigate the world around them too!</p> <p>Thinking about different senses is a great way to learn about all animals. What are their senses like? How does that help them think about the world differently to us?</p> <p>This was a fantastic question, Georgina, and we hope you enjoyed these answers as much as we enjoyed answering them.</p> <p>Excellent hearing means dogs can identify people arriving at a home or oncoming traffic at a walkway. With such great hearing, dogs can help people in need navigate the world around them too!</p> <p>Thinking about different senses is a great way to learn about all animals. What are their senses like? How does that help them think about the world differently to us?</p> <p><em>Written by Susan Hazel and Eduardo J Fernandez. Republished with permission of <a href="https://theconversation.com/curious-kids-how-far-away-can-dogs-smell-and-hear-139959">The Conversation.</a> </em></p> <p><em> </em></p>

Beauty & Style

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8 things we do that really confuse our dogs

<p>Dog behaviour is extraordinarily flexible – this is why we can keep them in our homes and take them to cafes with us at the weekend.</p> <p>Nevertheless, there are ways in which evolution has not equipped dogs for the challenges of living in our world, and puppies must learn how to cope.</p> <p>These are some of the things we do they struggle to understand.</p> <p><strong>1. We leave them alone</strong></p> <p>As born socialites, dogs make friends easily. Puppies are intensely interested in spending time with other dogs, people, and any species willing to interact with them socially. They usually play, rest, explore and travel with company. Yet we often leave dogs alone: at home, in kennels or the vet clinic.</p> <p>In these situations, naive dogs can’t be sure we’ll ever return to collect them. Only after experience are they likely to expect a reunion, and even then, their experience depends on the context.</p> <p>At home, we may try to enforce dog-free zones. Naturally, many dogs protest. How can they stay with their (human) social group when they’re separated behind impenetrable barriers (doors)? This explains why dogs so often demand to be let inside when their human family is there, and why those with separation-related distress frequently find some solace in being indoors.</p> <p><strong>2. We are visually driven</strong></p> <p>Dogs live in an olfactory world, while ours is chiefly visual. So, while TVs may offer a visual feast for humans, parks and beaches are an olfactory banquet for dogs.</p> <p>An additional challenge is dogs move while investigating the world, whereas we often sit still. They may not relish the inertia we enjoy in front of a noisy, flashing light-box.</p> <p><strong>3. We change our shape and smell</strong></p> <p>Shoes, coats, wallets, briefcases, bags and suitcases: countless smells cling to these items after we take them into shops and workplaces, then back to our dogs. Cleaning products, soaps, deodorants and shampoos also change the scents our dogs are used to.</p> <p>Towels, hats and bags change our shape when we’re using them. And when we’re pulling them on, jumpers and coats alter our visual outline and may catch dogs unaware.</p> <p>Dogs change their coats at least once a year. In contrast, we change our external cladding every day. This means the odours we carry are changing far more than dogs have evolved to expect.</p> <p>In their olfactory world, it must be puzzling for dogs to encounter our constantly changing smells, especially for a species that uses scent to identify familiar individuals and intruders.</p> <p><strong>4. We like to hug</strong></p> <p>How humans use their forelimbs contrasts sharply with how dogs do. We may use them to carry large objects a dog would have to drag, but also to grasp each other and express affection.</p> <p>Dogs grasp each other loosely when play-wrestling, and also when mating and fighting. Being pinned by another dog hinders a quick escape. How are puppies to know what a hug from a human means, when that behaviour from a dog might be threatening?</p> <p><strong>5. We don’t like to be bitten</strong></p> <p>Play-fighting is fun for many puppies and helps them bond with other dogs. But they must monitor the behaviour of other dogs in play-fights and know when they’ve used their tiny, razor-sharp teeth excessively.</p> <p>Humans are much more susceptible to pain from playful puppy jaws than other dogs are, and so we can react negatively to their attempts to play-fight with us.</p> <p>Dogs interact with objects almost entirely with their muzzle. And to feed, they use their jaws, teeth and tongue.</p> <p>Dogs also “mouth” other dogs when playing, expressing affection and communicating everything from “more” to “please don’t” to “Back off!”. So, naturally, they try to use their mouths when communicating with us, and must be puzzled by how often we take offence.</p> <p><strong>6. We don’t eat food from the bin</strong></p> <p>Dogs are opportunists who naturally acquire food anywhere they find it. In contrast, we present them with food in dishes of their own.</p> <p>Puppies must be puzzled by our reaction when we find them snacking from benches and tables, in lunchboxes and kitchen bins. We should not be surprised when dogs unearth food we left somewhere accessible to them.</p> <p><strong>7. We share territories</strong></p> <p>We visit the territories of other dogs, bringing back their odours, and allow unfamiliar human and canine visitors to enter our dogs’ home. Dogs have not evolved to accept such intrusions and threats to their safety and resources.</p> <p>We shouldn’t be surprised when our dogs treat visitors with suspicion, or when our dogs are treated with hostility when we bring them to the homes of others.</p> <p><strong>8. We use our hands a lot</strong></p> <p>Sometimes our hands deliver food, scratches, massages and toys. Other times, they restrain dogs, trim nails, administer ointments or tablets, and groom with brushes and combs that may pull hair.</p> <p>No wonder some dogs grow to fear the human hand as it moves about them. We can make it easier for dogs to accept many types of hand-related activities if we train them to cooperate with rewards.</p> <p>But humans often misread their fear and may even greet it with violence which compounds the problem. Hand-shy dogs can easily become defensive and find their way into pounds and shelters, where life expectancy for nippers and biters is poor.</p> <p>On the whole, dogs show a remarkable ability to adapt to the puzzles we throw at them. Their behavioural flexibility offers us lessons in resilience and how to live simply and socially. Our challenge is to understand the absence of guile and malice in everything they do.<!-- Below is The Conversation's page counter tag. Please DO NOT REMOVE. --><img style="border: none !important; box-shadow: none !important; margin: 0 !important; max-height: 1px !important; max-width: 1px !important; min-height: 1px !important; min-width: 1px !important; opacity: 0 !important; outline: none !important; padding: 0 !important; text-shadow: none !important;" src="https://counter.theconversation.com/content/122616/count.gif?distributor=republish-lightbox-basic" alt="The Conversation" width="1" height="1" /><!-- End of code. If you don't see any code above, please get new code from the Advanced tab after you click the republish button. The page counter does not collect any personal data. More info: http://theconversation.com/republishing-guidelines --></p> <p><em><a href="https://theconversation.com/profiles/melissa-starling-461103">Melissa Starling</a>, Postdoctoral researcher, <a href="https://theconversation.com/institutions/university-of-sydney-841">University of Sydney</a> and <a href="https://theconversation.com/profiles/paul-mcgreevy-139820">Paul McGreevy</a>, Professor of Animal Behaviour and Animal Welfare Science, <a href="https://theconversation.com/institutions/university-of-sydney-841">University of Sydney</a></em></p> <p><em>This article is republished from <a href="http://theconversation.com">The Conversation</a> under a Creative Commons license. Read the <a href="https://theconversation.com/8-things-we-do-that-really-confuse-our-dogs-122616">original article</a>.</em></p>

Family & Pets

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10 quick remedies to make your home smell better

<p>Unfortunately, no matter how much of a clean freak you are, sometimes unpleasant odours are unavoidable.</p> <p>However, these simple hacks will help you remove the smells that arise in different areas of your house.</p> <p><strong>1. Bin</strong></p> <p>Wash indoor bins with hot soapy water to remove smelly debris. Leave a few used fabric softener sheets in the bottom of the bin to absorb odours.</p> <p><strong>2. Stove</strong></p> <p>If you have a spill on your stovetop or oven, sprinkle salt on the spilt liquid to remove the burned smell. This trick will also make it easier for you to clean up later.</p> <p><strong>3. Freezer</strong></p> <p>To combat a musty freezer smell, place a clean sock with dry coffee grounds inside your freezer.</p> <p><strong>4. Microwave</strong></p> <p>If you have an unpleasant smell in your microwave, fill a large bowl with 1 ½ cups of water and three chopped lemons with a fragrant spice. Bring to boil in the microwave and then leave it to steam for 15 minutes. Leave the door open for an hour to air the microwave out once you remove the bowl.</p> <p><strong>5. Dishwasher</strong></p> <p>Before cleaning the dishwasher, check that the drain hose isn’t crimped and check the bottom of the machine for chucks of food or gunk. Then, pour 3L of vinegar into the bottom and let it sit for an hour. Run the dishwasher through a fully cycle. If the odour persists, call a plumber as it might be a sign of a bigger problem.</p> <p><strong>6. Cutting boards</strong></p> <p>Scrub your cutting board with a mixture of lemon juice and baking soda or salt. Rinse well.</p> <p><strong>7. Fridge</strong></p> <p>To remove an odour from your fridge, pour baking soda into a plastic container (like a margarine tub) and poke holes in the lid. Change as often as you need to.</p> <p><strong>8. Toilet</strong></p> <p>Pour one cup of vinegar into the bowl and let it sit for five minutes. Scrub briskly and then flush to remove the smell.</p> <p><strong>9. Mattress</strong></p> <p>If your mattress smells musty, spray with a disinfectant to kill the odour-causing bacteria. In between cleanings, sprinkle baking soda onto the mattress and wait 15 minutes before vacuuming.</p> <p><strong>10. Closet</strong></p> <p>If you are a coffee lover, you can hang clean socks filled with coffee grounds in your closet to remove an unpleasant smell.</p> <p>What are your tricks to remove unpleasant odours? Let us know in the comments below. </p>

Home & Garden

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The surprising reason why you love the smell of old books

<p class="Default"><span>If you’ve been known to breathe in </span><span>the well-worn pages of an old book</span><span> and find it so intoxicating that you can’t stop, you’re not alone. Chances are that t</span><span>he scent reminds you of something familiar and </span><span>comforting. Well, s</span><span>cience tells us that familiar smell is chocolate and coffee</span><span>.</span></p> <p class="Default"><span>According to a </span><span style="text-decoration: underline;"><strong><a href="https://heritagesciencejournal.springeropen.com/articles/10.1186/s40494-016-0114-1" target="_blank"><span class="Hyperlink0">study published in Heritage Science</span></a></strong></span><span>, two scientists conducted an experiment performed at Birmingham Museum and Art Gallery. According to their findings, the majority of the 79 test subjects found the old-book smell to be similar to chocolate and coffee.</span></p> <p class="Default"><strong>So, how does it work?</strong></p> <p class="Default"><span>Well, materials like chocolates and books can release small amounts of </span><strong><a href="http://hellogiggles.com/finally-know-old-books-smell-amazing/" target="_blank"><span class="Hyperlink0"><span style="text-decoration: underline;">volatile organic compounds</span></span></a></strong><span> (VOC) into the air. Our noses pick these up and then our brains </span><span>interpret </span><span>them. </span></p> <p class="Default"><span>Researchers were able to take these compounds and run them through scientific equipment (think sensors and a combination of the ‘ole gas chromatograph and mass spectrometer) where they</span><span> identif</span><span>ied various smell components.</span></p> <p class="Default"><strong>So, what does this mean?</strong></p> <p class="Default"><span>Stemming from their study, the same researchers are hoping to find a way to preserve smell in the same way society preserves old buildings so that future generations can enjoy them. They believe that smell plays an important role in shaping a person’s memories since it is so closely tied to the memory center in the brain.</span></p>

Books

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15 ingenious tips to make your house smell delicious

<p class="first-para">Never fear having unexpected guests walk into a smelly living area again! Here are a few simple DIYs to try – from unlit candles and stovetop potpourris to those sweet-smelling sachets you keep in your underwear drawer.</p> <p><strong>1. Tape dryer sheets to your air vents</strong></p> <p>Love the smell of Laundromats? Recreate it at home by taping a dryer sheet to any air vents. Air blowing through will distribute the scent throughout your home.</p> <p><strong>2. Deodorise shoes with teabags</strong></p> <p>Hate smelly shoes in your corridor, cupboards and under your bed? Place dry tea bags in the toes of your tennis shoes to nix any nasty odours and absorb excess moisture. Lavender, mint or apple-scented shoes, anyone?</p> <p><strong>3. Deal with musty tent odours</strong></p> <p>Insert dryer sheets inside empty luggage, camping gear (especially tents and sleeping bags!) and sports equipment before you stash them away in your basement, attic or garage. The sheets stop musty damp smells from permeating.</p> <p><strong>4. Vacuum bag air freshener</strong></p> <p>Soak a cotton ball in cologne and insert it into your vacuum cleaner bag. That way, as you vacuum, the scent will be slowly released into the room.</p> <p><strong>5. Make a stovetop potpourri</strong></p> <p>Lingering smells in your kitchen? Simmer water is a small saucepan, add one sliced lemon, a sprig of rosemary, a teaspoon of pure vanilla extract and about two inches of water. Bring to boil and reduce the heat, then continue to simmer on low, topping up with water as the water evaporates. You can use this over several days, adding more water when necessary.</p> <p><strong>6. Burn Le Papier d’Armerie</strong></p> <p>This <span style="text-decoration: underline;"><strong><a href="https://www.saison.com.au/papier-d-armenie-incense-original.html" target="_blank">scented paper</a></strong></span> is a staple in almost every French household. Simply tear away a sheet, fold accordion-style, and light one end before blowing. As the paper smoulders, it leaves an incredible floral and sandalwood scent that lasts for days.</p> <p><strong>7. Keep unlit candles in closets</strong></p> <p>Candles don’t have to be lit to work their magic. You can place your scented candles, unlit, in linen closets to have the fabrics absorb the scent.</p> <p><strong>8. Make your own drawer diffusers</strong></p> <p>Get small muslin bags and stuff them with your favourite dried herbs, flowers and spices, then place in your drawers to make your clothes smell lovely, naturally.</p> <p><strong>9. Mix your own vodka room spray</strong></p> <p>Create your own room spray by mixing a cup of water with two tablespoons of vodka and 25 drops of essential oil. Try different combinations based on what room you’re spraying – lavender and vanilla for a relaxing bedroom, peppermint and rosemary to help to stay alert in your study, and cinnamon, clove and tea tree – with their natural antibacterial properties – for the bathroom and kitchen.</p> <p><strong>10. Don’t throw out your citrus rinds</strong></p> <p>Fill your hollowed-out lemon and orange halves with sea salt and leave them to absorb nasty smells in your fridge.</p> <p><strong>11. Make frozen garbage disposal pellets</strong></p> <p>Make ice cubes out of white vinegar and lemon and orange peels. Once they’re frozen, remove from tray and place in a zip-lock bag to keep in the freezer. To use, put the cube down the garbage disposal and run it. Not only will it freshen up – the ice actually helps to sharpen the blades.</p> <p><strong>12. Deodorise dingy carpet</strong></p> <p>Simply sprinkle a box of bicarb soda on your carpet or rug, leave it for 30 minutes, and then vacuum it up (along with the smells).</p> <p><strong>13. Grind coffee beans</strong></p> <p>Buying coffee beans and grinding them at home isn’t just great for your morning brew – it also makes your house smell wonderful. Try hanging clean socks or pantyhose filled with coffee grounds in your musty closet or that stale-smelling freezer – it works wonders, trust us.</p> <p><strong>14. Deodorise your freezer with vanilla</strong></p> <p>After throwing out all the unidentified frozen foods in there, wipe down the sides with a cotton pad dampened with pure vanilla extract.</p> <p><strong>15. Cooking fish? Use preventative measures</strong></p> <p>When cooking fish, especially when frying, set a small bowl of white vinegar next to the stove to absorb and neutralise the smell.  </p> <p>What methods do you use to get rid of bad smells in your house? Share your tips in the comments below.</p> <p><em>Written by </em>Kathleen Lee-Joe<em>. First appeared on</em> <a href="https://www.domain.com.au/" target="_blank"><strong><em><span style="text-decoration: underline;">Domain.</span></em></strong></a></p>

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How to rid top 3 household odours

<p><em><strong>Craig Connelly, the Odour Dude, has been in the odour removal business since 2002. He is the odour expert behind <a href="http://www.odordude.com/"><span style="text-decoration: underline;">The Odour Dude</span>.</a></strong></em></p> <p>I’ve treated thousands of different pongs over the years but the main three I deal with are as follows:</p> <p><strong>1. Urine odour in the floor of the toilet</strong></p> <p>If you have grandkids, then you may well relate to the fact that the little tinkle sound at night is not always the sound of your bank account gaining interest, but rather the misfire from the grandson as he miscalculates the weight of the gumboots and the head wind in the ablution block.The end result being, your handpicked Italian tiles are soaked with urine with a bouquet of a sniper's armpit the following day.</p> <p>To complicate the situation, some cunning person thought it may be amusing to put grout between tiles just to make life more fun. Untreated grout soaks up urine and other nasties in deep and starts to produce the door one associates with an alley way rather than our beloved “Oval Office”. But never fear dear reader as I have a simple solution for you that is more cunning that the grout guys evil plan.</p> <p><span style="text-decoration: underline;">The solution using a simple household product</span><br /> A simple solution is to grab a bucket and put 3 litres of warm water in it. Add to this one scoop of quality laundry powder and let it sit for five minutes. The laundry powder will start to produce oxygen and you will see bubbles in the mix. (If you don’t see bubbles then your laundry powder has no sodium percarbonate in the ingredients and you may need to consider another plan equally as cunning or buy one with sodium percarbonate in it). Sodium Percarbonate produces oxygen when mixed with warm water which is a brilliant recent urine neutraliser.</p> <p><span style="text-decoration: underline;">Method</span>: Pour some of the solution onto the affected area and let it soak in deep. If you have a wet vacuum then tip a bit more on and start to suck it out straight away. Repeat and you will be jim-dandy before you can say “jim-dandy”. If you don’t have a wet vac then use towels to absorb the fluid.</p> <p><strong>2. Dog odour in the house</strong></p> <p>Dog odour is a very common issue and the most interesting thing about dog odour is the owners of the dog can never smell it. They say “Smell, what smell? I can’t smell a thing”. However, for someone walking into the house for the first time, it can be like being hit in the head with a piece of 4 x 2. Not an ideal way to greet your guests and once their nasal passages stop bleeding and the eyes are prised apart, they tend not to stay long even if you have a special pasta sauce recipe passed down from your mum. So in order to keep your guests in the house longer, here are some simple solutions. But first let’s look at the two most common causes of dog odour. Those with a weak stomach should now leave the room!</p> <p><span style="text-decoration: underline;">1. Dog bum odour<br /> </span>In most cases of strong dog smell, the odour typically comes from the dog’s rear end rubbing on carpet or furniture. This varies per dog breed (some dog breeds don’t have this issue whereas other are prone to it). So the solution if you have an offending rear end breed, is to spot clean the areas of the carpet that the dog tends to favour as a resting spot, using a good quality wet vac and a reliable carpet cleaner product with a small percentage of alkaline in (always spot test your carpet or furniture first in an inconspicuous area first to avoid colour damage or staining). In each dog owners house, there are normally three to four areas where the dog sits for long periods (near the dinner table or TV are good spots to start with) that should be spot cleaned. After spot cleaning and allowing the carpet to dry dust a bit of fragrant carpet deodoriser on and before long your friends will start to return and smile enthusiastically when they sample your homemade sauce.</p> <p><span style="text-decoration: underline;">2. Dog fur odour</span></p> <p>The other odour from dogs comes from the oils in their fur. Once again this is determined a lot of the time by the breed of dog and the odour always seems to be more prominent in areas where they tend to chill, such as lounge suites, near the TV etc. A similar odour removal approach to dog bum odour is used, where a slightly alkaline based cleaner is required to help break down the oils in conjunction with a good quality wet vac with strong suction to assist in removing the residues. Once again if you do not have a wet vac then a folded towel will suffice.</p> <p><strong>3. Household cooking smells</strong></p> <p>So now we are entering tricky territory as there are many types of cooking smells and many different causes, so I will start with the common one first: fried food.</p> <p>Frying foods produces two elements that odour removers like me despise. The dirty two that we don’t like to mention are steam and oil, which when combined are a formidable force to reckon with, particularly when they build up over many months or years. The steam and oil rise during the cooking process and embed themselves in the paintwork on the ceiling and walls, plus curtains, and carpet. Add to the mix some pungent spices and you have a difficult job on your hands.</p> <p><span style="text-decoration: underline;">Solution: </span><br />1. Buy a small container of Sugar Soap and mix with hot water to the recommended dosage written on the bottle using a 10 litre bucket. Wash the ceiling thoroughly using a soft cloth dipped into the sugar soap and hot water solution. (If the water ain't changing colour then you are doing it wrong). The sugar soap and heat from the hot water should start to break down some of the oil residues and they will transfer to the cloth. For bad cases, you may need to wash the ceiling area two to three times, changing the water each time.</p> <p>2. Remove all curtains and have then dry cleaned. Be sure to tell your dry cleaner you are dealing with cooking odours so they do a good job.</p> <p>3. Have your carpets cleaned professionally using an Alkaline Carpet Cleaner as a pre-spray (helps breaks down the oil). Ensure the carpet cleaner understands you are wanting to remove odours however do not use highly fragranced cleaning products as it will be more difficult to determine if the process has worked.</p> <p>4. Once everything is dry, reassess the odour contamination. It should be considerably better, if not please see below for more options.</p> <p>5. This should only be done if the smell persists. Try Ozone Gas for a minimum of 24 hours and reassess. If smell persists after an Ozone treatment you will need to paint the ceiling and walls using a sealer coat first then a top coat.</p> <p>*Please note: Quite often the sugar soap can change the appearance of the ceiling due to the water being cleaner in certain areas versus an area where you cleaned just before changing the water.</p> <p>Note: Always spot test your cleaning products on all surfaces you are about to treat first in an inconspicuous area. Not all fabrics and substrates react the same and although we use these techniques we take no responsibility for staining or damage to substrates you are treating. Consult an industry professional first if you have any doubts about the quality of your items prior to treating.</p> <p>Here’s to an odour free house!</p> <p><em>For more odour removal tips, visit Craig’s site <span style="text-decoration: underline;"><strong><a href="http://www.odordude.com/">The Odour Dude</a>.</strong></span></em></p> <p><strong>Related links:</strong></p> <p><a href="http://www.oversixty.co.nz/lifestyle/home-garden/2016/09/how-to-remove-mildew-smell-from-towels/"><span style="text-decoration: underline;"><em><strong>How to remove mildew smell from towels</strong></em></span></a></p> <p><a href="http://www.oversixty.co.nz/lifestyle/home-garden/2016/07/natural-ways-to-make-your-home-smell-better/"><span style="text-decoration: underline;"><em><strong>7 natural ways to make your home smell better</strong></em></span></a></p> <p><a href="http://www.oversixty.co.nz/lifestyle/home-garden/2016/06/can-your-house-be-too-clean/"><span style="text-decoration: underline;"><em><strong>Is it possible for your house to be too clean?</strong></em></span></a></p>

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How to remove mildew smell from towels

<p>There’s nothing worse than folding a stack of squeaky-clean towels only to catch a whiff of something less-than-sweet. Damp, musty towels not only smell awful but are also a breeding ground for mould, bacteria and other nasties. Here’s how to eradicate the smell for good.</p> <p><strong>1. Make sure you’re clean before you use your towel</strong></p> <p>Sounds strange, but the bacteria that builds up on our body ends up being transferred to your towel. If you’re a “in and out of the shower” kind of person, spend an extra few minutes thoroughly washing “sweaty spots” with a body wash or bar of soap to prevent bacteria transfer.</p> <p><strong>2.</strong> <strong>Always hang your towels</strong></p> <p>A balled up towel, even one heading for the wash, is almost guaranteed to get mouldy. Residual bacteria builds up on damp towels so ensuring that your towel is hung up either on a hook or towel rack ensures even drying.</p> <p><strong>3. Keep your machine clean</strong></p> <p>Ever wondered why your washing machine sometimes gets clogged up or slimy? Apart from washing powder residue it can also be due to a build-up of skin cells. People shed about one billion dead skin cells every day. Most of these end up in your washing machine. Try and disinfect your washer at least once a week to remove build up and keep it clean.</p> <p><strong>4. Choose a heavy duty wash</strong></p> <p>For the best result, wash towels in groups of no more than three. Choose the hottest setting and add in-wash booster/stain remover and hygiene rinse (like Dettol) along with your detergent. Make sure you remove your towels as soon as the wash cycle finishes and hang them to dry, ideally somewhere sunny as sun kills bacteria and mould.</p> <p>Have you got any nifty tricks for super clean smelling laundry? Share them with us in the comment section below.</p> <p><strong>Related links:</strong></p> <p><a href="/lifestyle/home-garden/2016/08/your-bed-sheets-could-be-making-you-sick/"><span style="text-decoration: underline;"><em><strong>Your bed sheets could be making you sick</strong></em></span></a></p> <p><a href="/lifestyle/home-garden/2016/08/how-to-clean-your-bathroom-like-a-professional/"><span style="text-decoration: underline;"><em><strong>How to clean your bathroom like a professional</strong></em></span></a></p> <p><a href="/lifestyle/home-garden/2016/08/ways-to-ripen-your-avocado-in-minutes/"><span style="text-decoration: underline;"><em><strong>5 ways to ripen your avocado in minutes</strong></em></span></a></p>

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5 plants that will keep your home smelling lovely

<p>For some people, the scents that accompany store-bought air-fresheners, candles, and wax melts are overpowering and headache-inducing. And while simple fresh air is lovely to have in the house, sometimes you feel like doing more than just opening your windows right up. So we’ve got some plants you should consider keeping around your home if you want to keep the air fragrant without being overpowering.</p> <p>Top tip: Position any of these plants by a window that gets a breeze for delicious wafts of subtle scent.</p> <p><strong>Basil:</strong> While you’re probably used to using this in dishes, you might not have realised you can get many different scented varieties of this beautiful herb. Try lemon or lime scents for a fresh, clean aroma.</p> <p><strong>Lavender:</strong> Not just a pretty face, lavender is another gorgeous-smelling herb with a deep, sweet scent.</p> <p><strong>Geraniums:</strong> With members of the geranium family smelling like everything, including orange, nutmeg, and chocolate, these gorgeous flowers can add colour and fragrance to your home.</p> <p><strong>Mint:</strong> We all know that mint is a great way to freshen up one’s breath after a meal, but its potently clean, fresh cent makes it a great way to freshen up the air in your kitchen or bathroom.</p> <p><strong>Anise hyssop:</strong> This one’s just for the liquorice fans, because it has a distinct liquorice smell and taste. You can actually eat this plant – it’s great as an unusual flavour enhancer for salads.</p> <p><strong>Related links:</strong></p> <p><span style="text-decoration: underline;"><strong><a href="http://www.oversixty.co.nz/lifestyle/home-garden/2016/05/uses-for-hydrogen-peroxide-at-home/"><em>28 great uses for hydrogen peroxide at home</em></a></strong></span></p> <p><span style="text-decoration: underline;"><strong><a href="http://www.oversixty.co.nz/lifestyle/home-garden/2016/04/most-common-stains-on-furniture-revealed/"><em>Most common stains on furniture revealed</em></a></strong></span></p> <p><span style="text-decoration: underline;"><strong><a href="http://www.oversixty.co.nz/lifestyle/home-garden/2016/04/infographic-house-cleaning-schedule/"><em>The ultimate house cleaning schedule</em></a></strong></span></p>

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