Biology pertaining to humans.

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Consequence of touching Formaldehyde

I accidently touched formaldehyde some days ago. Skin on my hand got dehydrated as if I had placed it in salt solution. I washed it with water and it returned to normal state after 5 minutes. But now ...
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1answer
75 views

What causes Paresthesia (Pins and Needles) at a cellular level?

I've looked it up in plenty of places like the Wikipedia page and such, and it is clear that the most common cause of Paresthesia is either a fair amount of pressure on a specific patch of skin ...
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13 views

What are conditions for a membrane to be settled ? (centrifugation)

The cell membranes have 60% of proteins and 40% of lipids. And we know that medium density of proteins is 1,2 g/cm3 and the medium density of lipids is 0.92 g/cm3. How can we calculate the medium ...
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1answer
54 views

What's the minimum distance of focus for the lens of a human eye to reach maximum flatness?

According to the Wikipedia article on eye accomodation, the range in which a human eye can focus is from 7 centimetres away up to essentially an infinite distance. Of course, people can't see things ...
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119 views

Is solving cancer required in order to avoid aging?

When the telomerase enzyme is not active the telomere shortens every time the cell duplicates leading to a reproductive limit (Hayflicks limit). On one hand this is a believed reason for aging. On the ...
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582 views

Do we actually get more sick (flu/cold) during winter?

The word flu derives from the Italian phrase "influenza de freddo" meaning "influence of the cold". Indeed it is that time of the year when my colleagues seem to have the flu/cold more often than ...
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2k views

Why do we sweat after drinking water and running?

Why do we sweat after running? Also we sweat sometime after drinking lots of water. Why it is so? Can someone please enlighten me in this regard?
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3answers
10k views

Death because of distilled water consumption

One of my friends said that I would die if I drank distilled water (we were using it in a chemistry experiment) I gave it a go and surprisingly did not die. I did a bit of Googling and found this ...
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19 views

Functioning of BCG vaccine

I read (from Nature Volume507, S4–S7 (06 March 2014) : For reasons that are poorly understood, BCG protects only infants; it is ineffective in older children and adults. Its efficacy also ...
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2answers
5k views

Why do vaccines cause your arm to hurt?

When you get a shot for a vaccine (for example, the annual flu vaccine), the nurse frequently indicates that your arm will ache for a day or two, maybe more. This ache is typically not just a pain ...
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16 views

The distance the electromagnetic field of the heart can be detected

A very smart friend of mine seems to get taken in by junk science. He started telling me last night that the electromagnetic field of the heart can be detected beyond 30 feet. What is the actual ...
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13 views

Association of shorter telomeres with heart disease

From this paper Those with shorter telomeres in blood DNA had poorer survival, attributable in part to a 3.18-fold higher mortality rate from heart disease (95% CI 1(.)36-7.45, p=0.0079), and ...
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Where people age at slower pace - mountain or seashore [closed]

where people live longer - mountain or seashore? If mountain then at what elvation they age at a slower pace?
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1answer
145 views

Why can't ciliary muscles in the human eye relax like other muscles?

I had laser eye surgery a decade ago, but in recent years my eyesight has become significantly myopic. I consulted an ophthalmologist to see if this was eye strain because I work at computers a lot, ...
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2answers
193 views

What is the eye muscle status when you stare at distant view through a glass wall?

The book said when you look at object close to you, the eye muscles contract and vice versa. I wonder what will be the status of the eye muscles when I stare at distance view (such as a mountain) ...
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67 views

How many different smells can a human recognize?

How many different smells can a human recognize? If the space of smells is not discrete, how many dimensions it has (for example, the space of colors is three-dimensional).
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59 views

Evolution of Homo Erectus to Homo Sapiens

I just read an article on Wikipedia and noticed that some similarities between Homo Erectus and Homo Sapiens in the "Comparative table of Homo species". My question is; Is it possible to say that ...
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36 views

Is it easier to burn a calorie of fat or a calorie of a carbohydrate?

Say someone eats 100 calories of chocolate vs. 100 calories of carrots. Something tells me that eating the chocolate will lead to you generating more fat. Will it? Is it harder to burn the calories ...
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2answers
256 views

How does a veggie-less diet affect the human body?

I have some question, which I'm sure would fit better in the fitness section but proper answers should probably come from someone that knows biology. My question is rather simple. How can a person ...
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52 views

From a purely biological perspective, how does an optimal human diet look? [closed]

There is hardly any subject as contested in the media as what humans should eat. Usually, such discussions are devoid of actual scientific reasoning, though they all claim to be backed by scientific ...
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1answer
83 views

Raising two legs together while lying on bed

Let's do some exercise(duh!) Ok so lie on the bed. Lift your left leg. Put it down. Lift your right leg.Put it down. Easy? Now lift your left leg and without putting it down, lift your right leg. ...
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1answer
82 views

Why don't we have more cone cells (bigger fovea)?

Background Apart from being able to sense color, cone cells are able to perceive finer detail and more rapid changes in images, because their response times to stimuli are faster than those of rods. ...
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3k views

Can humans eat grass?

Can a human eat grass and digest it? Could it be possible to use it as food just like other plants such as wheat or beans?
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25 views

Surrogacy Post Fertilization

The wikipedia page on surrogacy highlights two main forms of surrogacy: Traditional Surrogacy and Gestational Surrogacy. Traditional surrogacy inseminates the surrogate mother with sperm, while ...
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175 views

Is urine dirty as soon as it leaves the human body?

Human urine is sterile as long as it is in the human body. But is it dirty after leaving the human body? Could you get sick from it, if you drink it or don't wash your hands, for example?
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69 views

Electronic cigarettes (e-cigs), any health risks?

Background: An electronic cigarette (e-cig or e-cigarette) is a battery-powered device which simulates tobacco smoking patented in 1963 by Herbert A. Gilbert. It generally uses a heating element ...
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2answers
112 views

Are humans the only animal that requires “clean water”?

I've seen a number of animals - dogs, cats, squirrels, ducks and geese, etc drink from puddles, some of them were muddy, others had green flora growing under water. Same goes for lakes and rivers. A ...
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3answers
5k views

Healing process in mouth wounds

When we have an external wound the wound generally tents to clot and there is a layer of solid scab formed. Now,Yesterday while brushing my teeth i somehow hurt my gums and it got all bloody but ...
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Nearly Exhaustive List for Cholesterol Pathways

I have run across an interesting case that is similar to only two others I've encountered. What makes it interesting is the combination of undetectable (under normal testing conditions, can elaborate ...
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30 views

How can one accurately diagnose human hearing loss without surgery?

In a human, if you were to avoid a tympanotomy, how could you distinguish between a blocked Eustachian Tube, a ruptured eardrum, or Perilymph Fistula? For instance take the situation where a young ...
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2answers
884 views

How do we know that everybody's DNA fingerprint is unique?

How do we know that everybody's DNA fingerprint is unique? I know, I know, everybody's DNA is unique. But when we do DNA fingerprinting, we're looking at very specific regions of high variability. ...
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50 views

What causes DNA to skew in gel electrophoresis?

In gel electrophoresis, what causes effects like these (see collumn 11 in the first one, an collumn 6 in the second). ? (These images were samples that I took from an online activity we did for ...
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2answers
3k views

Why do toenails grow much slower than fingernails?

As the title suggests, I've noticed that my fingernail grow much faster than my toenails. For instance, I usually trim my fingernails every two week or so, but for toenails the number would be about 6 ...
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59 views

Improving myopia

I have a friend who no longer needs glasses. He previously had myopia in both eyes but over the years it has improved until he no longer needs glasses clinically. He's had glasses for over 30 years ...
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38 views

Is there a scientific name for the field of study focusing on the hemispheres of the brain and their control of opposite sides of the body?

I'm assuming this field of study would focus on motor controls, movement, and exercise, but it could also focus on activities which strengthen the corpus callosum or stimulate a specific half of the ...
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56 views

Do Asian women have more difficult births than Europeans?

I recently heard a claim that Asians in general have more difficult births than Europeans. Is this true? I have found a few studies(1,2) on the effect of ethnicity on birth outcomes but they seem to ...
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2answers
39 views

Why do humans circulate monosaccharides instead of disaccharides as in plants?

Plants transport food mostly in the form of disaccharides like sucrose but humans transport them in the form of a monosaccharide - glucose. What is the reason behind this ?
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177 views

Why do most breast cancers occur in women?

According to Korde et al. (2010): Male breast cancer accounts for less than 1% of all cancers in men and less than 1% of breast cancers. This raises the question: Why do most breast cancers ...
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31 views

Systemic sensory confusion?

Sometimes when a person gets touched on one part of the body they feel it else where and may think it came from a different part of the body. What causes this? Other examples are similar to why you ...
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2answers
90 views

How does the brain know where a signal came from? What is the addressing system

I am an electronic engineer so I am thinking about this from an electronics outlook. How does the addressing system work, As I see it, the nervous system is small parallel branches attached to larger ...
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89 views

Chills down the spine with certain music?

I am sure many of us know the feeling of that tingling chill down our spines when listening to certain music. I experienced this most when my younger brother played an emotional piano piece for a ...
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1k views

Why do sneezes come in pairs or more?

I very rarely sneeze just once, usually there's two coming in a row, and I've noticed the same thing in other people and even in animals. Is there any reason for this?
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56 views

Will we ever be able to read the thoughts from brain activity? [closed]

Is it theoretically possible to "read" a human's thought from brain activity? As far as I know we can already detect in what kind of mood a person is. Personally, I don't think "reading" word by word ...
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27 views

How usable is the Human Metabolic Model to predict biomass?

In order to use the Human Metabolic Model for Flux Balance Analysis of specific cancer cell lines, we would like to know what sort of flux values have been determined for the Human Metabolic Model. ...
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17 views

What are good data on the Human Metabolic Model and where can I get them?

Trying to get a good SBML representation of the Human Metabolic Model for use in Flux Balance Analysis and drug targetting (i.e. gene knockout) simulations. What are good sources for these data? ...
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57 views

Does playing music during sleep actually suppress rather than rouse the brain?

I've long been interested in the effect of music/sound on dreaming, and even built 2 apps that play music during REM period. Now I'm looking at this article about FMRI studies of a sleeping brain, and ...
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18 views

Is there a homeostatic setpoint for number of hours of sleep required by a human?

I've heard this TED.com talk about dieting and it mentions that there's a very definitive setpoint within the human brain about how much a human should weight. The speaker mentions that after as much ...
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4answers
12k views

What is the armpit hair for?

Modern human beings, especially women, cut their armpit hair. It seems to me the armpit hair is trivial/useless. Shortly speaking, what is the armpit hair for?
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43 views

Do humans have a “dominant” neurotransmitter system/sensitivity within their brain?

I've recently heard a podcast, in which Dr. Helen Fisher suggests that there are "4 broad personality types", and each one is associated with a particular neurotransmitter: The corresponding ...
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214 views

Are humans an eusocial species?

In the evolution of sociality among animals, different degrees are acknowledged. Some species present overlapping generations, some division of labor, and the minority present reproductive division. ...