We brush our teeth daily, but do you know everything you need to know about dental care and hygiene? Believe it or not, there is a lot more than most people realize. Luckily, here are several apps that can help you.

●Brush DJ

    You should brush your teeth for full two minutes as recommended by dentists, but that time can be difficult to judge. Many recommend you listen to music, because many songs are just around two minutes in length. Brush DJ has loads of great tunes that will get you into the two­minute habit. There are both songs to listen to, and videos to watch, and you'll find a variety of awesome tunes.

●Orasphere

    It's recommended that Orasphere videos be used by dentists for their patients, so they can learn about procedures. Those who do use these videos say that the software can greatly decrease the amount of time it takes to explain procedures to patients.

●American Dental Association(ADA)

    Everything you ever wanted to know about your teeth, and then some, can be found on the American Dental Association(ADA) website. You'll find loads of great articles that have the latest news about dentistry（牙科）. Those interested in dental careers will find plenty of information to head them in the right direction, and there's even a section devoted to public dental programs, including Give Kids a Smile and Fluoride in Water.

●DDS GP

    Here is more presentation software that explains all types of dental procedures. This is helpful for dentists to have, because they can better explain procedures to their patients.

●Dentistry IQ

    You can find information for dentists, hygienists, assistants, office managers, and more at Dentistry IQ. You can also get information about new products, clinical practices, and much more. In addition, you can learn about career opportunities, the most recent practices, and a whole lot more.

He was 50 years old when I was born, and a "Mr. Mom" long before anyone had a name for it. I didn't know why he was home instead of Mom, but I was young and the only one of my friends who had their dad around. I considered myself very lucky.

Dad did so many things for me during my grade-school years. He asked the school bus driver to pick me up at my house instead of the usual bus stop that was six blocks away. He always had my lunch ready for me when I came home—usually a peanut butter and sandwich that was shaped for the season. My favorite was at Christmas. The sandwiches would be covered with green sugar and cut in the shape of a tree.

As I got a little older and tried to gain my independence, I wanted to move away from those "childish" signs of his love. But he wasn't going to give up. In high school and no longer able to go home for lunch, I began taking my own. Dad would get up a little earlier and make it for me. I never knew what to expect. The outside of the bag might be covered with his way of a mountain scene (it became his trademark or a heart with the word "Dad-n-Angel" in its center. Inside there would be a note with that same heart or an "I love you". Many times he would write a joke or a riddle. He always had some silly saying to make me smile and let me know that he loved me.

    I used to hide my lunch so no one would see the bag or read the note, but that didn't last long. One of my friends saw the note one day, grabbed it, and passed it around the lunch room. My face burned. To my astonishment, the next day all my friends were waiting to see the note. From the way they acted, I think they all wished they had someone who showed them that kind of love. I was so proud to have him as my father. Throughout the rest of my high school years, I received those notes, and still have a majority of them.

    And still it didn't end. When I left home for college (the last one to leave), I thought the messages would stop. But my friends and I were glad that his action continued.

I began getting letters almost every Friday. The front-desk worker always knew who the letters were from—the return address said, "The Hunk." Many times the envelopes were addressed in crayon and along with the enclosed letters were usually drawings of our cat and dog, stick figures of him and mom and if I had been home the weekend before, of me racing around town with friends and using the house as a pit stop. He also had his mountain scene and the hearten-cased inscription, "Dad-n-Angle".

Do you like spicy food?

    What's your opinion on spicy food? Some people cannot handle even the smallest amount of chili-red pepper-in their dinner while others can't get enough of it.

    Scientists have long been puzzled by why some people love chili while others loathe it. Plenty of research has been done on the subject, dating as far back as the 1970s. Previous results showed that a love of chili is related to childhood experiences, and cultural influences affect our taste buds too. But the latest study has found that a person's love of spicy food may be linked to his or her personality more than anything else, CBC News reported.

    "We have always assumed that liking drives intake-we eat what we like and we like what we eat. But no one has actually directly bothered to connect these personality traits with intake of chili peppers,"said Professor John Hayes from Pennsylvania State University, who led the study.

    But before you look at the study, you should first know that "spicy" is not a taste, unlike sour, sweet, bitter and salty. It is, in fact, a burning sensation that you feel on the surface of your tongue. This got scientists thinking that maybe a love of spicy food is brought about by people's longing for thrill, something they usually get from watching action movies or riding a roller coaster.

    In the study, 97 participants, both male and female, were asked to fill out questionnaires about certain traits of their personality, for example, whether they like new experiences or tend to avoid risks. They were then given a glass of water with capsaicin, the plant chemical that makes a chili burn, mixed into it.

    By comparing the answers to the questionnaire and what participants said they felt about the spicy water, researchers found that those who tended to enjoy action movies or take risks were about six times more likely to enjoy the spicy water.

    Interestingly, we used to believe that the reason some people can withstand spicy food is that their tongues have become less sensitive to it. However, this latest study has found otherwise. "It's not that it doesn't burn as badly, it's that you actually learn to like the burn," Hayes explained.

    New research brings some good news for lovers of spicy(辛辣的) foods, after finding that eating hot red chili peppers might help to extend lifespan（寿命）.

    Consuming hot red chili peppers might reduce death risk, say Chopan and Littenberg from the research team. In hot peppers, such as Mexico peppers, the strong flavor comes from a compound(复合物), which does not exist in sweet peppers or onions. Studies have suggested that this compound can offer a welth of health benefits.

    A study of more than 16,000 people in the United States revealed that individuals who consumed red chili peppers had a lower risk of death from all causes over an average of 18 years than those who did not eat the spicy food. Compared with participants who did not consume hot red chili peppers, those who did were found to be at 13 percent reduced risk of all-cause death.

    For example, a recent study reported by Medical News Today, found that the compound might have the potential to stop breast cancer, while an earlier study linked the compound to a reduced risk of digest system cancers. Still, the available data suggested that hot red chili pepper consumption was most strongly associated with a reduced risk of death from heart disease.

    While the researchers are unable to identify the concrete compound by which red chili peppers might extend lifepan, the team says that it is likely due to the compound that is effectively against obesity(肥胖症).

    Overall, the team says that these latest findings support those of the 2015 study, linking spicy food intake to reduced risk of death by showing “a significant decrease in death associated with hot red chili pepper consumption.” However, Chopan and Littenberg note that the earlier study was only conducted in Chinese adults, so the now research makes these findings more credible.

Quantum mechanics (量子力学) is a branch of science that studies the smallest particles (粒子) in the universe, like atoms (原子) and even smaller things. It might sound super complex, but let's break it down in simple language.

Imagine you have a small particle, like an atom. In the world of quantum mechanics, these particles don't behave like the things we see in our everyday lives, like balls or cars. Instead, they act kind of like waves and particles at the same time, which is really strange!

One of the most famous ideas in quantum mechanics is the "Uncertainty Principle", raised by physicist Wemer Heisenberg. This principle says that we can't precisely know both the position and the speed of particle at the same time. It's not because our measuring tools are bad; it's because the particles themselves are naturally uncertain.

Another weird thing about quantum mechanics is something called "Entanglement". Imagine you have two particles that are connected in a special way. If you change one of them, the other instantly changes, no matter how far apart they are. It's like they're talking to each other faster than the speed of light, which goes against what we know from everyday experiences.

Quantum mechanics also deals with probabilities. Instead of saying, "This particle will be here at this exact time," scientists say, "There's a certain chance it'll be here, and a certain chance it won't." It's like predicting the weather, but on a super small scale.

In a nutshell, quantum mechanics is a strange and fascinating world where particles act both like waves and particles, where you can't know everything about a particle at once, and where particles can be mysteriously connected no matter how far apart they are. It's a mind-boggling field that challenges our understanding of how the universe works, and even though it's tough to grasp, it's an essential part of modern physics.