0
votes
2answers
439 views

Which range are the Therapeutic Indices of Currently-Prescribed Benzodiazepines in?

A compound's therapeutic index is defined as: $$TI = \frac{LD_{50}}{ED_{50}}$$ What range are the therapeutic indices of benzodiazepines in? For the method of administration I would prefer ...
4
votes
1answer
233 views

In the diffraction pattern of a protein crystal what exactly determines the intensities of the spots?

What I have read is that the contents of the unit cell affect the intensities, but how? I am also unclear on why you need to know the symmetry of the unit cell, what is that used for? I understand ...
8
votes
1answer
662 views

How do Benzodiazepines induce Rewarding (Euphoric) effects?

Benzodiazepines are a class of drugs that serve as positive allosteric modulators of the GABAA receptor by binding to their own "site" on the aforementioned receptor. By doing this they produce ...
2
votes
1answer
55 views

Trigger allergic reaction in non-allergic people?

Is there a proven way to trigger an allergic or allergic-like reaction in non-allergic people? I have wondered if this is possible, since allergies are basically just a form hypersensitivity - so ...
2
votes
1answer
77 views

Does this patient have HHV6 or HCMV after transplant surgery?

I have been given mock results from a PCR test on blood samples taken from kidney recipient patients and their donors. The PCR reaction can detect single copies of viral DNA. I have been asked to ...
6
votes
1answer
278 views

How selfish is Dictyostelium slug formation?

Dictyostelium is a slime mold which is well known for having a single cell free living phase and other some conditions (e.g. when food is scarce) for forming communal piles of cells called 'slugs' ...
9
votes
2answers
79 views

Can we disambiguate competing molecular mechanisms of learning and plasticity by measuring electrical activity of neurons?

I have been reading with fascination about the several molecular- and cellular-scale mechanisms and structural changes that underlie what we refer to as long-term plasticity. For instance, [1], [2], ...
1
vote
1answer
69 views

What Conditions must Drugs satisfy for them to be Deliverable via the Transdermal route?

What Conditions must Drugs satisfy for them to be Deliverable via the Transdermal route? I assume a high $\log{P}$ (lipophilicity) would be one, are there any others?
3
votes
1answer
129 views

How to wash the column during protein purification with GST tag?

I have been working with GST tagged proteins for the last 4 years and after loading the cell lysate into the column I was washing it with 20-30 column volumes of PBS and sometimes my proteins were ...
1
vote
1answer
500 views

What is the advantage of circular genomes for bacteria and linear genomes for other organisms?

Bacterial are a great group of organisms. They have circular genomes and never went toward linear genomes while other organisms show the opposite strategy and don't have circular genomes (disregarding ...
3
votes
1answer
177 views

Does an allergic reaction kill body cells?

I have wondered what actually happens in an allergic reaction that causes the symptoms such as pain, rash etc. Is it possible that the human body actually kills its own cells in the process?
4
votes
2answers
2k views

Simple diffusion of lipid-soluble molecules through phospholipid bilayer — does anything get “stuck” in transit?

It's a pretty elementary concept, and when I first learned of it I don't think I had the foundations to even think of such a question, but I found myself the other day thinking about the amphipathic ...
6
votes
2answers
829 views

Why is absorbance at 280 nm for protein solution going up when I measure repeatedly?

I have been measuring my protein solutions' concentrations by diluting them in water 20 fold with a final volume of 100 uL and then measuring the absorbances of these solutions in 96 well plates with ...
1
vote
1answer
1k views

Molecular cause of cramps, spasms and strengthening in muscles? (incl. intro to muscle contraction)

When motor neurons are stimulated to trigger an action potential, this potential propagates down the spine, eventually reaching a neuromuscular junction, causing the release of acetylcholine (ACh). ...
3
votes
2answers
599 views

What are gram negative and positive bacteria?

I've just finished a course of double antibiotics for Helicobacter pylori in my stomach. I looked up H. pylori and found that it was a gram-negative bacterium. I looked up gram-negative and didn't ...
2
votes
1answer
42 views

Range of feasible coefficients in an unlimited growth model

If you are given an unlimited growth model in the form: $\frac {dP(t)}{dt} = k P(t)$ Obviously the population growth would never be unlimited, but let's presume for the moment that we are ...
2
votes
2answers
230 views

How do bats distinguish between day and night?

How do bats distinguish between day and night? Do they hunt at night - if yes, how they know that? Are they afraid of sunlight?
-2
votes
3answers
157 views

A question regarding evolution

I'm not a biologist so bear with me. I know that the DNA molecule carries extremely large amounts of information. If the process of evolution is driven by completely random process .I think about it ...
2
votes
1answer
71 views

What is the mechanism behind ventilatory acclimatization?

In my respiratory physiology lectures, my professor explained that hypoxia-induced hyperventilation occurs in 2 stages when people try to acclimate at high altitudes. My question is about the ...
2
votes
0answers
67 views

Why did animals evolve genders? [duplicate]

The majority of animals have two genders, and both are needed in reproduction. It seems like it would be more advantageous for creatures to be hermaphrodites, since they could mate with any member of ...
1
vote
1answer
197 views

What is the biochemical reason for mental fatigue?

Is it known exactly why the brain needs sleep? What's dropping low / going high when we experience mental fatigue? I can see why low glucose could result in mental fatigue, are other reasons known?
6
votes
1answer
322 views

Excretion of small kangaroos while in the pouch

How is the excretion of small kangaroos done when they are in the pouch of their mother, fastened onto her teat? My question is what happens with the products; do they accumulate in the pouch?
4
votes
2answers
251 views

Question about equilibrium potential formula

My biology book says, that the equilibrium potential for an ion with a charge of +1 is: $$E_{ion}= 62mV \biggl(\log\frac{[ion]_{outside}}{[ion]_{inside}}\biggr)$$ Where does the 62 mV come from? How ...
1
vote
0answers
20 views

Which classes of drugs (filed by their pharmacology) induce a release of β-endorphin?

Which classes of drugs (filed by their binding sites) induce a release of β-endorphin? I know of agonists of the nAChRs and 5-HT1A and ethanol. Are there any others? Please cite journal articles ...
1
vote
0answers
385 views

How do Opioids Stimulate a Histamine Release?

Histamine is a neurotransmitter that also has peripheral functions such as the regulation of gastric acid secretions, allergic responses, etc. I know that opioids stimulate a release of histamine but ...
6
votes
2answers
204 views

What kind of bird species is this?

Every now and then I got a glimpse of this bird which I'm pretty sure is not native to Northern Germany where I live. There are at least three of these birds around but I usually only see something ...
1
vote
1answer
559 views

What is Chronic immobilization stress (CIS)?

I am trying to self study BNDF a little bit when I found this article: Abstract Stress impacts multiple systems within the CNS, including the hippocampus. A key molecular mediator in hippocampal ...
0
votes
2answers
48 views

Manipulating Gut flora in vivo

I am tasked with designing an in vivo experiment in humans that requires manipulating the gut flora in one sample group to gauge its effect. Please suggest ways of doing this besides administering ...
3
votes
0answers
34 views

Do sulfate reducing bacteria help during the formation of the mineral dolomite in low temperature environments?

Do sulfate reducing bacteria help during the formation of the mineral dolomite in low temperature environments? Wikipedia says The actual role of bacteria in the low-temperature formation of ...
1
vote
1answer
131 views

How do circulating androgens contribute to higher rates of hirsuteness in some women?

I was reading up on ethnic groups in which the women are naturally more hirsute (such as South Asian women) in the context of evolving standards of beauty. I came across this statement on a forum: ...
2
votes
3answers
3k views

Do cold blooded animals generate any heat?

In explaining energy and work to an 8 year-old I said that all conversion of energy generates heat as a by-product. For example, cars generate heat in their engines and running generates heat in our ...
9
votes
2answers
7k views

What is the difference between SOLiD, 454, and Illumina next-gen sequencing?

I've started teaching myself about next-generation sequencing in preparation for a new job, and I'm wondering what the main differences are between the 454, SOLiD, and Illumina/Solexa machines, in ...
5
votes
1answer
249 views

Why does strenous exercise cause vision of “lights”?

I had a hard climb a week ago. I got so tired then any time I closed my eyes I saw these lights inside my head. I see these lights almost every time that I run fast or some thing like that. What are ...
6
votes
1answer
201 views

How does skin healing work?

I stacked my bike and split my head right open. About three weeks later the scab falls off and the skin is sealed over, like magic! How does it all work? How does the brain know that part of the ...
6
votes
3answers
5k views

What's the difference between a plant and an animal?

Are there some living things where the distinction between plant and animal is blurry or unclear? I wouldn't know where to put something like yeast. I also thought of photosynthesis, but then I ...
4
votes
1answer
980 views

Why is second pKa value of phosphoric acid different across different sources?

Am I missing something very fundamental here for phosphoric acid's second pKa value? I check the Wikipedia page and these are the values: (1) 2.148, (2) 7.198, (3) 12.377 Then I check Sigma-Aldrich ...
4
votes
0answers
80 views

What are the mechanisms that cause bananas to ripen? How is or isn't it related to the banana peel ripening? [closed]

So recently our commercial kitchen got some bunches of bananas with a curious feature. On the inside they were firm and delicious (no jokes, please), on the outside they looked incredibly sickly. ...
9
votes
1answer
168 views

Systems identification in small neural network

When analyzing data from cortex, we often try to understand what each neuron does in terms of its inputs from other neurons - a specific kind of a systems identification strategy. Most current ...
7
votes
1answer
1k views

Can you consider a human as alive, or is it the cells on the body that are alive?

Sorry if this question seems strange, but in the recent time I have been interested in the question of what life is and how you can define life. My question: How long can individual cells live on a ...
9
votes
2answers
771 views

Which sex has higher variance of reproductive rate in modern societies - male or females?

Who has a more varied reproduction rate in modern western societies - men or women? The average rate is the same of course, but I wonder which sex have higher variance - higher variance means that ...
5
votes
1answer
2k views

How does formaldehyde cause protein-DNA crosslinking?

How does formaldehyde cause protein-DNA crosslinking? I would guess it's because the strongly polar water molecule interacts strongly with polar residues on a protein-DNA complex, and adding a less ...
10
votes
2answers
356 views

Why Do Most Humans & Cats Have Blue/Bluish Eyes At Birth?

I've read that the eye color at birth for most humans and for cats may not always be the the true genetic color at first. This is due to the lack of melanin in the iris. This makes sense as there is ...
2
votes
0answers
40 views

What does effect would Sulforaphane have on Kennedy's Disease?

Sulforaphane is a isothiocyanate found in cruciferous vegetables including broccoli and cauliflower. Its 2D structure is as follows: It's been found to serve as a histone deacetylase 6 (HDAC6) ...
1
vote
1answer
27 views

Do Fatty Acid Synthase Inhibitors Selectively induce Apoptosis in Cancer cells without inducing the same in healthy human cells?

Do Fatty Acid Synthase (FAS) Inhibitors (e.g. cerulenin) selectively induce apoptosis in cancer cells without inducing the same in healthy human cells?
3
votes
2answers
86 views

How common is bacterial mediated transformation? In plants? In animal cells?

The most common method to transform plants is by soaking plant tissue in cultures of agrobacteria (this is not their current classification) which transfer DNA into the plants. Is lateral gene ...
11
votes
4answers
6k views

What nutrients can humans absorb in the mouth?

For instance, I realise being able to absorb simple sugars in the mouth is pivotal in the rapid action of oral glucose gel. Thus I was wondering what nutrients in general can be absorbed directly ...
4
votes
1answer
816 views

What is the average volume of the hippocampus?

I'm trying to find any information on sizes of the hippocampus? Ideally in the average adult male & female brain
9
votes
2answers
2k views

Does Sansevieria trifasciata really absorb Carbon Dioxide at night?

There's a claim that Sansevieria trifasciata (Mother-in-law’s Tongue) generates oxygen from carbon dioxide during the night. This seems surprising to me: that process requires energy; plants generate ...
9
votes
2answers
181 views

Birds placing sticks on train tracks?

I live in a semi-rural area in Germany, close to a park which trains go through every 20 minutes. Today, I saw something that left me perplexed. There is a large population of birds that look like ...
4
votes
1answer
112 views

Why do we yawn?

I've read a new study which suggests that yawning may help you keep a cool head. Also, the findings might hold some hope for sufferers of insomnia, migraines, and even epilepsy. Is there any ...

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