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8

First, there are two different isomers of the lactic acid, the L(+)- and the D(-)-form. Both differ in the position of the OH-group in the molecule: Both turn polarized light in different ways, the D(-) to the left and the L(+) to the right. The physiological form of lactic acid for the human body is the L(+) form, which is taken up in the gut and then ...


3

Lactic acid has been found to act as a fuel for the muscles. Refer to: http://www.nytimes.com/2006/05/16/health/nutrition/16run.html?_r=0 Most athletes consider lactic acid their enemy, and think that training helps eliminate the metabolic waste product from their muscles so the muscles will function longer and harder. But UC Berkeley physiologist ...


4

There is not very much transport of ions or water through the upper layer of the skin, mainly responsible for that is the stratum corneum (SC). Through this layer you will get only with small lipids and also substances which are able to penetrate the lipid layer of the cells like chloroform or DMSO. I think therefore that it is pretty unlikely that you can ...


-2

I doubt it would be efficient. Your skin is a tight, water proof membrane designed to keep water and ions and other molecules inside while keeping the outside out. The molecules that are absorbed through the skin tend to be hydrophobic organic molecules. Ions, which any dissolved salt in water would become, do not easily pass through cellular membranes or ...


3

As I recall from textbooks I read as an undergrad, one mechanism of drug tolerance works by increasing the necessary thresh-hold at a synapse such that larger concentrations of neurotransmitter or more-frequent action potentials in the upstream axon were required to depolarize the membrane and propagate the signal. Yes - usually through a reduced ...


11

Women have erections too! These erections are called clitoral erection. These erections are usually accompanied by vaginal lubrification. Just like men, the absence of norepinephrine during the REM phase of the sleep causes erections. In women, this phenomenon is called Nocturnal clitoral tumescence while it is called Nocturnal penile tumescence in men. In ...


3

That is correct. When plasmodium infects red blood cells, it consumes the hemoglobin in the cell, leaving the heme behind, which they can not metabolize (heme is a heterocyclic porphyrine ring with an iron atom coordinated in the center). Since the heme (or $\alpha$-hematin) causes the production of reactive oxygen species and thus oxidative stress, it has ...


1

When you cry, you produce tears, which come out of your tear ducts. These are not only open to the eyes but also have a connection to your nose, see the image below: A part of your tears runs through this connection and mixes with the mucus which is present in your nasal system making it thinner and allow it to flow more easily. If the tear flow is ...


0

REST is not a deep sensation. We define various types of waves that are drawn using electroencephalogram. $\alpha$ waves: Awake but resting position. Frequency: 8-13 Hz. They originate from occipital region $\beta$ waves: Alert wide awake person. They originate from frontal region. Frequency about 14-30 Hz. $\theta$ waves: They occur under stress ...


2

Body temperature results from a balance between the heat generated by our cells and the heat “lost” to the environment. Heat created by our cells comes from the energy used to keep us alive. Heat is lost through our skin and the air we breathe out. Human beings have an average temperature of 98.6 degrees Fahrenheit. The brain monitors body temperature and ...


4

The Human Microbiome Project collected samples as shown in the image below from healthy volunteers: They give an estimate of about 8 Million genes in the human microbiome, which is about 360x the number of genes in the human genome. See here for their press release with a lot of information. Additionally these two articles are as well interesting, if you ...


2

Human Microbiome Project According to Published data on HMP website: The human microbiome consists of all the microorganisms that reside in or on the human body. They may cause illness but some are necessary for good health. There total count is 10 times more than Human cells. ~800 genomes had been sequenced. ~5000 Human sample had been used. Include 14 ...


2

Difference between rest and sleep There are many factors which describe the difference between rest and sleep. Rest Rest occurs with conscious breathing. This allows the autonomic nervous system (ANS) to rest. The autonomic nervous system belongs to the peripheral nervous system. ANS controls many organs and muscles in the body. In most situations, ...


2

There are two levels to take your question at. The first is simpler but I'm not sure if it is what you are looking for: If you imagine the heart and all the blood vessels in your body as a closed plumbing system with no leaks (not entirely accurate) then when the heart contracts and squeezes the blood from the ventricles the total surface area the blood is ...


27

Sometimes men wake up with an erection in the morning. Why does this happen? Shortly speaking: REM (Rapid Eye Movement) is one phase of sleep. During this phase we dream and some of our neurotransmitter are shut off. This include norepinephrine, which is involved in controlling erection. Norepinephrine prevents blood to enter the penis (preventing the ...


3

Yes it can but it is very rare. Most often when you get a nosebleed it is either a vein or capillary that ruptures. However in some cases it is arterial bleeding which is always an emergency. I have honestly noticed when I have nosebleeds often each one is worse than the previous with some having a lot of bleeding but still no gushing from an artery. ...


3

Yes. Usually only in the case of someone with hemophilia (no blood clotting) but it could theoretically occur with any serious uncontrolled nosebleed. Since blood in the stomach tends to cause vomiting, you could also lead to a scenario where someone who was uncomfortable with blood would pass out due to being scared of the blood and then aspirate (puke and ...


5

As @WYSIWYG pointed, muscular atrophy is the main cause for height decrease. A spine injury leads to neural impairment and paresis / paralysis. This affects directly muscular trophism. It also limits physical activity, this being another favoring factor for muscular atrophy and overweight issues [1]. Association of bone degenerative processes (osteoporosis, ...


9

Yes, it can, but it is extremely rare. ... nosebleeds are rarely fatal, accounting for only 4 of the 2.4 million deaths in the U.S. in 1999 [1]. The main issue is that epistaxis can be a sign of potentially fatal diseases: The instances in which nosebleed is potentially fatal are those in which there is a history of recent head injury, severe ...


5

Any injury, that results in external bleeding can lead to death, since it is a breach in the body's defenses and an entry point for pathogens. Explanation: When you have nose bleeding the blood must be coming from somewhere. Usually from inside your body. That means there is a hole in your body which is big enough for blood to stream out. That in return ...


1

Light can affect retina in many ways [1]: photothermal mechanisms - exposure to intense flashes of less than 20 microseconds that cause a rise in temperature of at least 10 degrees Celsius [5]; photomechanical mechanisms - exposure to flashes shorter than 5 nanoseconds [5]; photochemical mechanisms - light is absorbed by a chromophore and leads to the ...


2

Females are defined as the sex that produces that bigger gamete (ovule) while the males are those from the gender that produce the smaller gametes (spermatozoid). Because producing big gametes is costly, the number of females fix the reproductive limit in the population and in other words the variance in reproductive success in males is higher than in ...


10

I will just show the statistics of last attempt to mimic the brain process. Last year Japan launched there fastest supercomputer: K computer OR SPARC64 VIIIfx 2.0GHz Features: Manufacturer: Fujitsu Cores: 705,024 Linpack Performance (Rmax) 10,510 TFlop/s Theoretical Peak (Rpeak) 11,280.4 TFlop/s Power: 12,659.89 kW Memory: 1,410,048 GB ...


7

Interestingly this effect seems to be true - there is one paper which claims that fasting for three days leads to the depletion of unused (and especially damaged) immune cells to save energy. When food is back at normal rates, the body starts to renew these cells which have been depleted before. This process also seems to enhance the self-renewal process of ...


2

Thanks for the searching and quoting Ilmari. According to some theories, and perhaps there is some research on stool to support these, we can aid our intestines for producing beneficial bacteria by eating PREbiotic foods which supposedly help create a good environment in the intestines for producing healthy bacteria on its own. Some foods that are supposed ...


2

I am afraid you cannot build the classic ECG using only 1 hand. Probably, you can measure HR - heart rate accordingly to pressure detection and similar sensors and from that you can simulate ECG by picture. Simulate I mean you cannot build any reliably ECG curve on the monitor, but can show some waves after every heart beat.


1

Another possibility is K4 device and K4 device. Beyond spirometry it can measure other variables such as: Pulmonary Gas Exchange (VO2, VCO2) Breath by Breath Technology Telemetry Data Transmission up to 1000m Indirect Calorimetry Integrated GPS System Integrated Oxygen Saturation (SpO2) Integrated 12-lead Stress Testing ECG


3

What you are looking for is a spirometer. There are different types of spirometers serving different purposes like the Incentive spirometer and the peak flow meter. I would suggest that you go through the wikipedia page on it to get more info.


1

While it's always possible that a mutated eggplant will produce a new toxin, this is very unlikely. I don't know how much higher the mutation rate is near Fukushima than in general but the difference can't be huge. Even if it's, say, 5 or 10 times higher than normal (I'm making up these numbers), the risk is still tiny. Actually, plant breeders sometimes use ...


2

In general, if you want to know "exactly how much of X on an average is needed to be consumed to cause death", then the magic search term for Google is "LD50", that is the dose that kills 50% of victims. I've seen the LD50 for distilled water quoted as 90ml/kg for rats (that is, 90 ml per kg of body mass). I presume that figure comes not from theorising ...


1

I wouldn't say that a human is "likely" to get sick by drinking from a puddle, I'd say "at some risk". It isn't desperately dangerous, although don't take that as a recommendation. There are many infections you can get from water (bacterial, viral, amoebal, and I presume fungal). You don't want to risk them, but probably won't actually encounter them in that ...


9

During the time when you are not drinking water you still loose some water to sweating and urine. Sweating is (especially in hot climates) an important function of the body to maintain the body temperature in desired range. If this water is not replaced, the body gets dehydrated. This induces a reaction which reduces the activity of the "body thermostat" to ...


3

People with Shorter height may outlive Taller ones. It is a statistically established fact that they are more successful in terms of money, as the study published Journal of Applied Psychology, (Vol 89(3), Jun 2004, 428-441). But, still in the health, the counterpart succeed over the former. The Effect of Physical Height on Workplace Success and ...


1

In cerebral oedema the observations (blood pressure, pulse, respiratory rate etc.) can be all over the place. They can depend on the cause e.g. infectious more likely to have raised pulse (tachycardia) with lower blood pressure (shock) but with the anxiety there might be raised blood pressure. Then with the vomiting, a symptom of cerebral oedema, this could ...


3

The liver does quite a lot of "housekeeping". It is responsible for a lot of energy metabolism: Gluconeogenesis (the synthesis of glucose), Glycogenolysis (the breakdown of glycogen into glucose), Glycogenesis (the synthesis of glycogen from glucose). It is important for protein degradation as well as for amino acid synthesis, as well as in the lipid ...


1

Caffeine is the stimulant in tea. It has different effects on different people, but if you can sleep right after drinking it, it probably isn't strong enough to have long term 'refreshing effects', And yes, the duration of your sleep does matter. If you sleep for 12 hours, much more caffeine will filter out of your blood stream than after a 1 hour nap. ...


1

No, the L axis in the HSL color space does not really correspond to lightness as perceived by the human eye, except in the very crudest sense that, for given values of the H and S components, increasing L produces an increase in the perceived lightness. The L component of the standard HSL color space is simply calculated as the average of the lowest and the ...


9

There are 2 reasons for light to appear red through the eyelids. 1) Eyelids get a rich supply of blood which contains iron (in hemoglobin). The iron in blood absorbs all colors of light but reflects red light (reference). 2) Our tissue transmits red wavelengths of light very well, but it doesn't transmit blue or wavelengths of light towards the blue end of ...


16

Short answer, your eyelids does not block all light. Since they are only a thin layer of skin, the light is able to pass through although not completely obviously. Since the eyes are still completely functional when you close them, only covered by the eyelids, you are able to see when light strikes your face.


4

Alright, so this answer is partially based off the ideas presented by Bobson above. What i did was take his Excel spreadsheet idea and put that into the upper section. Then, I used the amounts used on the website he linked to check the proper amounts needed in the body. I then used those numbers to reverse engineer how much of each compound would be needed ...


3

I think that the advantages of using both hands with equal ease is quite evident whether it be sports, at your work or while you are doing your household chores. An obvious advantage is using both hands to write or draw with both at the same time. I would be focusing on the disadvantages that may be faced. 1) Ambidextrous people are more prone to ...



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