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By convention, positive current is assumed to be the direction of flow of positive charges. The trouble is that in many common situations (like this one), the current is actually carried by electrons which are negatively charged. It can be confusing. Blame it on Benjamin Franklin. The convention for current flow was based on his work, before anyone knew ...


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The tiredness associated with depression/stress is not due to the 'brain power' increasing but due to a change in what parts of the brain are active and/or disrupted sleep. Anxiety can cause issues to the brain and body over time. Brain power is relatively constant For the average adult in resting state the brain consumes about 20% of the body's energy. It ...


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The optimum cytoplasmic pH for performing physiological activities in plant cells is a neutral pH of around 7.2 to 7.4. The pH of apoplastic space outside plasma membrane and vacuolar pH is acidic ranging between 5 to 7. The thylakoid lumen is more fluctuating which varies during light / dark cycles and is highly acidic. The mitochondrial compartment and ...


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It comes down to the distinction between velocity and flow rate. While you are right that the water would leave a an increased velocity if you put your thumb over the end of the hose, this is deceptive, because the water is exiting the closed system, so it can go absolutely anywhere. So the fact that the velocity is increased could give one the impression ...


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A Japanese patent filed by Raymond Jay Bergeron, Jr JP2000514089A notes lysoferrin as the siderophore N1, N4-bis (1-oxo-3-hydroxy-3,4-dicarboxybutyl) diaminobutamate. The US counterpart of this patent, jointly filed as US application No. US08/783,306 and later issued as US 5,739,395 covers rhizoferrin in its embodiments. So it seems that the term lysoferrin ...


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Yes, birds do have a pharynx. Birds can breathe through the mouth or the nostrils (nares). Air entering these openings (during inspiration) passes through the pharynx & then into the trachea (or windpipe). {1} The larynx can't produce sound -- it's only there for breathing and eating. Instead, birds' sounds are produced at the bottom of the trachea, ...


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Worth noting, even you can perceive depth with one eye closed if you slide your head left and right. It's the same reason we can have 3d gifs that just rely on sliding the camera. Look up stereoscopic 3d lke these:


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Short answer About 0.79% of the light gets through on average, but there is variability across wavelengths and individuals. (variability between individuals seems to be correlated with density of macromolecules in the eyelid). Long answer: This is called "eyelid spectral transmittance". Lucky for you, Bierman et al (2011) sought to determine the ...


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There are 100+ gas phase compounds that come from humans. Find other information about most of these families of compounds from wiki. Full list of compounds is here Methods and findings are here


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A key component of body odour is the volatile thioalcohol, 3-methyl-3-sulfanylhexan-1-ol (3M3SH). The structure may be visualized as hexan-1-ol "substituted by a methyl group and a thiol group at position 3 " (pubchem) A major contributor to the formation of 3M3SH is the commensal bacterium, Staphylococcus hominis, which produces it as a by-...


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After reversible attachment of intrinsic factor-cobalamin complex to its ileal surface receptor, an energy-dependent process prevents removal of the complex from the cell surface by EDTA or acid; cobalamin dissociates from intrinsic factor and, as suggested by previous workers, binds to a molecule antigenically similar to transcobalamin II; and intrinsic ...


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Relaxation of vertebrate skeletal muscle is thought to occur in the absence of ${Ca}^{2+}$ as a result of tropomyosin physically blocking the binding of myosin to actin. This steric blocking model of muscle relaxation predicts that myosin subfragment 1 (S-1) will not bind to actin under conditions where the acto-S-1 ATPase rate is inhibited.[1] However, in ...


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As @Roshelle Perera points out, the textbook reason for differential solute and water movement in different parts of the LoH is osmolarity, which is nicely explained in this wikipedia article. Coming to an interesting point, about the movement of water across cell membranes through aquaporins, this is helpful:{1} The discovery of aquaporin membrane water ...


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Water across cell membranes occurs due to osmosis( which is based on a concentration gradient). so water diffuses through the cell membrane. sometimes water channels called aquaporins can be found. https://www.anaesthesiamcq.com/FluidBook/fl1_2.php https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/aquaporin In the loop ...


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There is no known mechanism for exchange of $\ce{O2}$ and $\ce{CO2}$ in a one-for-one fashion. Their transport across the alveolar membrane takes place by diffusion alone: both of them attain their equilibria with blood independently. Note that it is not necessary for inhaled and exhaled tidal volumes to be the same. In fact, under physiologic conditions, ...


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Generally textbooks take the following pedagogical flow in basic neurophysiology: Ions flow, so voltage changes propagate This is the "electrotonic part". The key concept is that if you add some ions or change the voltage of one part of a neuron, adjacent areas will also change in voltage as current flows 'passively'. The further away you go, the ...


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Cold extremeties are a reaction of endotherms where they reduce warm blood circulation to prevent losing core body temperature, otherwise the cold blood in your hands would lower your central blood pressure from 37'C, which makes the body less efficient and at risk of catching colds. The reaction is called vasoconstriction. quote: Active cutaneous ...


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Synaptic vesicles are on the order of tens of nanometers (for example Zhang et al give a mean diameter around 40 nm). Gap junctions are much smaller, on the order of 1-2 nm. Maeda et al measure one at 1.4 nm. Peptides the size of oxytocin present in the cytosol could theoretically travel through gap junctions. Vesicle-packaged peptides or molecules of any ...


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You can determine the diffusion potential mathematically with the Nernst equation. If it's not in the Nernst equation, it's not necessary. The charge of the ion matters (including valance), the temperature matters. Some universal constants are in the equation but these don't vary. Other factors that potentially matter are found in the other parameters, like ...


1

A good number of vegetables and fruits have >90% water contents; this includes cucumber, watermelon, etc. Even oranges, broccoli etc. have >80%. So it would not be hard to have enough water intake if the veggie/fruit/smoothie diet is not restricted to particular fruits or veggies. Slightly less detailed, but more reliable source agrees:


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At a constant volumetric flow-rate, the product of velocity and vesicle cross-section area is constant. In a real-life scenario, the volumetric flow-rate decreases when you hold your finger over the opening. So while water exits 'faster', at higher velocity, you would fill less bottles of water per minute.


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The key is vascular resistance. Pumps like the heart don't move fluid, they exert force ("push") on it, increasing the pressure. The movement happens subsequently because there is somewhere for the fluid to go, so it moves down the pressure gradient from a place of high pressure to a place of lower pressure. If you clamped their outputs (increased ...


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I think that it is missing some details. Note that the vast majority of urobilinogen (~80%) is actually eliminated via fecal elimination. I would recommend looking at the article on enterohepatic circulation, which provides more context on this issue. Basically, bile salts can be useful (even or especially after metabolism by bacteria), so a fraction is ...


1

Action potentials usually maintain muscle tone in skeletal muscles, but muscle cells are affected by other influences that can affect their contraction and thus the tone of the muscle. Smooth muscle occurs in the walls of hollow organs, most notably the blood vessels and the GI tract, and in a few other places. Contraction of smooth muscle is generally ...


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I am not sure if you are referring to a mechanochemical cycle of "stepping" of a myosin molecule along an actin filament, or a cycle of contraction and relaxation of a muscle cell as a whole. These take place on completely different timescales and control the binding and unbinding of the two proteins in entirely different ways. In the ...


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Graphs like these are based on a complete cross-sectional area. Myelination adds thickness, so if you want to add myelin outside and keep the same diameter, you have to have a smaller lumen inside the axon. As you can see in the "unmyelinated" plot versus diameter, smaller fibers have lower conduction velocity. Since the benefits of cross-sectional ...


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I would say that the quoted sentence from the Wikipedia gemmule article is wrong. The first sentence of the containing paragraph says: Asexual reproduction in sponges occurs via budding, either by external or internal buds. At face value, the two sentences together imply that sponges can reproduce by external budding, but that the external budding "...


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You could try DeVita, Hellman, and Rosenberg's Cancer: Principles & Practice of Oncology. It has detailed information on both biological and clinical aspects of cancer. Apparently, the publishers regularly release online updates to cover the latest developments in oncology. Reference to the current edition: DeVita VT, Rosenberg SA, Lawrence TS, editors....


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Although the OP might no longer be active, I'm comming back to this question, because there is a new study on this released in "Soft Matter". With simulations Yang et al., 2021, describe how corners of these almost perfect cubes might be formed. From the abstract: Using histology and tensile testing, we discover that the cross-section of the ...


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This is something I have been researching on and off for many years. I studied nutrition back in the early 1980s and our lecturer always said that "fats burn in the flame of CHOs". He said that the citric acid cycle was dependent on oxaloacetic acid - the predominant source was from glucose (pyruvic acid). https://www.sciencedirect.com/topics/...


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