42

Thiomersal is broken down into two compounds, thiosalicylate and ethylmercury (Ensink 2015). The thiosalicylate it is relatively non-toxic, and there is even some evidence that this compound could counteract some of the effects of mercury poisoining (Asadi et al 2010), though the mechanism of this inhibition has yet to be elucidated. Although they have ...


38

A single molecule of rhodopsin (actually the cis-retinal bound to it) can and actually does react to one photon (Purves et al. Chapter: Phototransduction in Neuroscience). It has been estimated that a single light-activated rhodopsin molecule can activate 800 transducin molecules, roughly eight percent of the molecules on the disk surface. Although ...


35

Percent of basal metabolic rate by organ (BC Campus Open Education): Liver and spleen : 27% Brain: 19% Skeletal muscle: 18% Kidneys: 10% Heart: 7% Other tissues (lungs, intestine, skin, bone, fat tissue, glands...): 19% Basal metabolic rate by 1 kg of specific organ tissue (kcal/kg of organ/day) (Table 5 from American Journal of Clinical Nutrition, 2010): ...


27

A recent study published in Nature by Tinsley et al. Direct detection of a single photon by humans found that it is possible for dark-adapted humans to respond to a single-photon stimulus, but only rarely. They used a source which created pairs of photons, and used one of the pair to determine whether the subject may have been exposed to a single photon. The ...


24

You're talking about long-wave UV, or UV-A radiation. In the 80s, experts claimed that this was a safe wavelength. Protection against UV-A was not part of sunscreen in the early days. Consequently, UV-A was (and still is) used in tanning beds due to its perceived safety over UV-B. However, a lot of research has been done since. UV-A is well understood now ...


11

Short answer: it's messy, and probably no answer will satisfy everyone. I'm only going to consider sex (I'm not going to mess with "gender") in humans. It's reasonable to consider sex as multidimensional rather than one-dimensional; see the various definitions listed below. The same individual could have different karyotypic, morphological, and ...


10

First gender and sex are not the same thing; as an old teacher of mine glibly put it, "sex is plumbing, gender is clothing," and even that is a gross generalization. The problem you are running into is using imprecise terms to ask a scientific question (sex, gender, and spectrum are all imprecise terms in biology). Precision in language is important in ...


8

Technically, we can sense the individual photons. Here is an quote from a cellular biology textbook: "Absorption of a single photon of light induces a conformational change in the rhodopsin molecule, which transmits a signal to a heterotrimeric G protein (called transducin ), which activates a coupled effector." (Karp's Cell and Molecular Biology 8e, 603). ...


7

Short Answer: As the comments mention, this is a hot topic for pseudoscientists to use as a selling point for their supplements. There is limited evidence that dietary acid intake significantly alters bone resorption, especially in the setting of normal renal function. This paper should answer all of your questions (emphasis mine): Frassetto, Banerjee, ...


7

Tarrare Tarrare was a showman who was renowned for his insatiable appetite including eating cats, dogs, and snakes sometimes raw. He is also said to have eaten many inedible items. At the time, he was alleged to have committed cannibalism of a 14-month-old baby and was caught in the act of cannibalising cadavers by hospital staff. He was given away as a ...


6

HeLa cells themselves are not pigmented, and usually appear translucent/gray under light microscopy. The growth medium may however be colored, and a common color is magenta. The tumors themselves will appear purple, as most tumors do, due to the broken vascularization. Tumors commonly secrete growth factors leading to angiogenesis, but the resulting vessel ...


5

There are (at least) two sides to this story. One is direct DNA damage being caused by UV-B light which happens to have photons with just the right amount of energy to interact with thymine. This has been known, and assumed not just during the 80s, but until the late 2000s to be The One major thing that causes cancer, or trouble in general (there's papers ...


5

The histogram you show isn't a distribution of age-at-death for individuals, it's a distribution of life expectancies for different countries. The post you link takes data from a table on this page. Interpreting the histogram you posted, we see average life expectancy seems to hit a wall around 85. This does not mean that individual human life span is not ...


5

This is a question I also remember wondering about when I was younger in school. Now as a professional it's way too obvious to even explain. But i think it's an important and common question, which warrants an example or two from common daily lab practice. Preface You have to understand that DNA is a molecule. It's really tiny. It's not trivial to work ...


5

If you are referring to the massive death toll among native Americans due to the epidemic disease outbreaks after first contact with European settlers, then the answer is rather straightforward (Science magazine News, 2016): The immune system is a complex structure, built over a person’s life in response to environmental conditions. Antibodies, proteins ...


4

Not everyone sweats in seconds after drinking water in summer. Also, sweating in seconds after drinking water is not likely due to water being absorbed (Nutrition Reviews, 2015): Ingested fluids are not immediately available for assimilation into the body. They are initially stored in the stomach, and there is little net absorption of water or solute ...


4

I encountered the following paragraph in the textbook Life: The Science of Biology: Some chemicals add groups to the bases. For instance, benzopyrene, a component of cigarette smoke, adds a large chemical group to guanine, making it unavailable for base pairing. When DNA polymerase reaches such a modified guanine, it inserts any one of the four ...


4

The most obvious issue is exposure to radiation. Once you're beyond the earth's atmosphere and magnetic field you are exposed to much higher levels of radiation from cosmic rays and solar flares. It's also possible that microgravity (weightlessness) could have effects on the reproductive system, but this isn't well studied yet. However, given the source you ...


4

NMR spectroscopy is a technology that is used to identify molecules. So-called "NMR spectra catalogs" document the spectra of various known compounds. Acquiring these spectra requires purified samples, expensive equipment, and time. In addition to making next-generations of this technology into something that would be practical for realtime "smelling", you'd ...


4

Warwick University's e-nose technology has been around for quite a while: https://warwick.ac.uk/fac/sci/eng/research/impact/electronicnose/ As far as I understand their technology, they sample gas, and analyse it using a solid state CMOS device to generate a signature signal for particular compounds/mixtures. The devices have been used in a variety of ...


4

Stress response has 2 main components: Quick response, within minutes, is by the Sympathomedullary Pathway (SAM): hypothalamus > sympathetic nervous system > release of adrenaline and noradrenaline from the adrenal medulla > stimulation of the heart, dilation of the muscle arteries, constriction of the gut and skin arteries, glcogenolysis (the breakdown of ...


4

How about non-target cells? I found several examples of that usage including: A book section titled: 9.3 How are steroid hormone target cells differentiated from non-target cells?1 Containing the following line: Thus, estrogen will stimulate mRNA and protein synthesis in a target cell, but not in a non-target cell. A book chapter titled: Target or non-...


4

2019-NCoV was first cultured by a Chinese group, as published here on January 24. China has not shared samples, but did share sequencing data in the linked paper and via GISAID. The Australian group at the Doherty Institute hasn't published yet, but did put out a press release today (January 29), and appears to be the first group outside of China to have ...


4

Isolating virus particles is important for accurate genomic sequencing, which in turn enables study of mutation rates and determination of hotspots, locations in the genome where mutations occur at higher rates: “Sorting individual viral particles makes it possible to identify and sequence the genomes of viruses one by one,” states Òscar Fornàs, head of ...


4

If you're interested in the biological or health effects of various chemicals, try to look up the Safety Data Sheet, or "SDS" or "MSDS", for that chemical compound. Going to your favorite search engine and plugging in your chemical of interest to the search term "SDS" or "MSDS" will almost always get you to some kind of answer — either what you're looking ...


4

The Gastroenterology paper you cite doesn't mention distended bellies at all. There is no dispute that fatty liver is a symptom of kwashiorkor. But the Wikipedia article makes it quite clear that the cause of the distended belly is edema. The extreme lack of protein causes an osmotic imbalance in the gastro-intestinal system causing swelling of the gut ...


4

8-10 years Keep in mind digging up bodies once they are nothing but bones was common practice at one time, look up the catacombs of Paris or just Ossuary. Human remains are not actually considered infectious once they have rotted away, not that they have much risk before that, but the smell of a corpse that still has soft flesh is remarkable unpleasant, ...


3

"Cortex" is a more general anatomical term for the outermost layer of a structure. It applies to both the cerebral and cerebellar cortex gray matter, as these are gray matter structures on the outsides of their respective parts of the brain. Nucleus is also a more general term; in the context of neuroanatomy, it refers to a cluster of cell bodies. Typically ...


3

During development of the brain neurons undergo several steps of differentiation. They transition from neuronal progenitors to mature neurons, resulting in different types of neurons, characterized most prominently by their primary neurotransmitter. During the differentiation, different genes are expressed, which in research is used to label specific cell ...


Only top voted, non community-wiki answers of a minimum length are eligible