Cells Definition and 450 Threads

  1. BillTre

    How many living cells on Earth?

    A NY Times article "Exactly How Much Life is on Earth?" (research article here, behind a paywall) says that there are about 1030 cells currently on earth and the total numbers of cells that will be on earth through its future lifespan is about 1041 cells. That is: It was implied in the...
  2. M

    I How to find the location of red cells?

    Hi ALL! I’m Mark. I’m new on this forum. Thank you very much to possibility of registration. This is my first post over here. I am student and I am writing my final work. I have a big and serious technical problem. Maybe some of you will be able to help me. I show results of my measurements in...
  3. berkeman

    Should Excel macros self-adjust when you delete lines above the affected cells?

    I just wanted to check to see if this is a known problem, or if my issue is more likely related to something different. I have an Excel spreadsheet that has a number of lines with comments and other information at the top, and then a matrix of cells below that on several rows. I had some Excel...
  4. Astronuc

    Perovskite semiconductors for solar photovoltaic cells

    I heard this while driving the other day. Progress On Perovskite Solar Cells | Earth Wise with Randy Simon https://earthwiseradio.org/podcast/progress-on-perovskite-solar-cells/ I wanted to check this out. Si melts at about 2,570°F (1,410°C). I'm not sure about 3000°F (1649°C), which...
  5. A

    How far are we from producing artificial cells in the lab?

    Synthetic biology is a rapidly growing field of science that aims at redesigning organisms for medical and agricultural applications, by means of biotechnology, genetic engineering, molecular biology and other methods by chemical, biological or computer engineering. As far as I understand it...
  6. BWV

    Methanol - H fuel cells for marine transport

    This privately held company developed a technology to extract H from methanol stored onboard marine craft, then the H can be used in a fuel cell for power. I assume the reason for a H fuel cell vs a direct methanol fuel cell (DMFC) in a marine vessel is that direct methanol cannot deliver large...
  7. W

    I Question about electromagnetic spectrum and solar cells

    Would it be possible to change all wavelenths to one frequency that would then be sent to a solar panel adapted for it, or once split could to be sent to cells that work in that range? In other words use all the light to produse electric power
  8. S

    Connection of two photovoltaic cells to produce larger current

    The answer from my teacher is two of these photovoltaic cells are connected in parallel. I can understand the parallel connection will produce same e.m.f but I don't understand why the total current will be greater than ##I##. I imagined one of the cell connected to a lamp. The current through...
  9. mktsgm

    Structural Questions about Memory B cells

    I have the following doubts regarding B cells. Normally upon the stimulation by a T-cell, the activated B-cell differentiates into plasma and memory cells. 1) What are the structural differences among the naive B-cells, activated B-cells, Plasma B-cells, and memory B-cells? I am interested in...
  10. A

    B Question regarding Beta-voltaic cells and their efficiency

    Why are beta voltaic cells so inefficient? Is it because the incident electrons are incredibly fast? According to a research, the incident electrons that get absorbed by the voltaic material are so fast that most of their energy is wasted as phonon and sonic energy. If we substantially slow down...
  11. Dario56

    Enthelpy of Reaction and Efficiency of Galvanic Cells

    For electrochemical energy devices such as batteries or fuel cells working reversibly, efficiency is defined as: η=ΔrG⦵/ΔrH⦵ Since cell operates reversibly Gibbs energy change of the system is equal to electrical work done by the cell, so we can instead just use standard Gibbs energy of...
  12. cemtu

    Why do monocrystalline solar cells have rounded/cropped edges?

    There were circular solar cells 30 years ago. Why do we have square-shaped solar cells now? Why square now?
  13. cemtu

    Purity of Polycrystalline Solar Cells vs Monocrystalline Solar Cells

    Why is the silicon purity of polycrystalline Solar Panels lower than monocrystalline Solar Panels? I have read this explanation somewhere in the internet but not sure if it is correct? Can somebody give me an explanation please?
  14. F

    Can prime editing fix every harmful mutation in all our cells?

    https://www.biorxiv.org/content/10.1101/2021.01.08.425835v1.full Can prime editing fix every mutation in every type of cell in the body?. From what I read in the article the editing efficiency of prime editing using adeno-associated virus is 1.82%, so what prevent us from repeating the same...
  15. F

    Germline mutations are more harmful than mutations in somatic cells?

    Sorry if my question contain misconceptions, I am just trying to learn biology on my own. From what I understood, every cell contain the same DNA and different cells express/use different parts of that DNA according to whether they are blood cells, skin cells, muscles cells etc. And cells get...
  16. I

    Galvanic cells: H+ vs H2SO4, and Br2(aq) vs Br2(l)

    For the reaction 12H+ + 2 IO(3-) + 10 Fe(2+) - > I2 + 6 H2O + 10 Fe(3+), the solution says that H2SO4(aq) is in the cathode. For the reaction 2 H2O2 - > O2 + 2 H2O, the solution says that H+(aq) is in the cathode and anode. When is H2SO4(aq) or H+(aq) more appropriate in the galvanic cell...
  17. T

    Some Common Meds Block SARS-CoV-2 Attachment to Cells

    Open access. https://www.nature.com/articles/s41586-021-03491-6 A more approachable synopsis at: https://www.news-medical.net/news/20210412/Tapeworm-infection-drug-blocks-SARS-CoV-2-damage-in-the-lungs.aspx Cheers, Tom
  18. M

    Engineering Mobile Comms: Number of Cells in Hexagonal Pattern

    Hi, I was looking at some notes and trying to understand the following statement which refers to the diagram below. "The number of cells in the radius ## D ## determined by ## N_c = D_R^2 ## where ## D_R = \sqrt{i^2 + j^2 + ij} ## where ## i## and ##j## are the number of cells along the ## u ##...
  19. Andrew Mason

    INKT (Invariant natural killer T cells) as a COVID-19 therapy

    I would be interested in hearing from the experts such as @Ygggdrasil about the prospects for a new therapy for COVID-19 using iNKT cells. According to this information page from the British Society for Immunology site: My interest was piqued by a recent announcement by AgenusBio (Agenus Inc...
  20. Rongeet Banerjee

    Medical How do Stem Cells help in Drug trials?

    How exactly do Stem Cells help in Drug trials ?Or do they really
  21. Mayan Fung

    I Recombination and open-circuit voltage in solar cells

    From the ideal diode model, we can derive the open-circuit voltage (Voc) as: $$ V_{oc} = \frac{nkT}{q} ln(\frac{I_L}{I_0} + 1) $$ where ##I_0## is the dark saturation current and ##I_L## is the light generated current. From the model, if the recombination rate increases, the dark saturation...
  22. M

    MATLAB Padding cells to make a single matrix

    Hi PF! I'd like to make one matrix from a cell. I've checked several suggestions, the most promising here but this did not work, giving me the unhelpful error Brace indexing is not supported for variables of this type. Error in cell2mat (line 42) cellclass = class(c{1}); Error in Feven (line...
  23. M

    What Type of Chemical Bonds Exist Between Tight Junctions in Human Cells?

    I know tight junctions between adjacent cells are very strong and the gaps are practically zero. But what types of chemical bonds are they? Are they covalent bonds or hydrogen or ionic bonds? I mean between the claudin and occludin proteins.
  24. mktsgm

    Quantum of cells directly infected by a virus?

    In any viral infection, we know that an invading virus enters the cell and damages them (cytolytic/cytopathic). This may be a starting point for inflammation down the road. Though initial inflammation may be beneficial, a longer than necessary inflammatory process proves more damaging than...
  25. jaumzaum

    Do we need salt bridges in Electrolytic cells?

    I was wondering if we really need salt bridges when doing Electrolysis. I would answer yes, because we need to neutralize the charges in both sides, or the potential difference of the Electrolytic cell will keep increasing until the generator that is connected to it is not able to supply any...
  26. mktsgm

    Medical Do the viruses damage our cells directly?

    Viruses when they infect us, enter the target cells, hijack the machinery and start producing their own Copy and eject out. So what? Question is, how do they directly cause injury to our cells? Do they harm injury our cells directly? Of course we know that our own immune system which becomes...
  27. F

    Action Potential in human cells

    Hello, I understand that the action potential represents a potential difference variation (depolarization) of the voltage across a cell membrane. This concept is generally presented in the context of nerve cells (neurons) as the change in potential across the axon membrane. What about the...
  28. TytoAlba95

    What is the meaning of definitive and specified Primordial germ cells?

    I'm stuck in a dev bio paper. The relevant extract is porovided below: Human germ cell development begins with the specification of PGCs, which is expected to happen at the onset of gastrulation (developmental week 2) in the posterior epiblast of early postimplantation embryos. During gestation...
  29. BillTre

    Pre-Eukaryotic Cells of the Asgard Superphylum Cultured in Japan

    The origin of advanced eukaryotic cells (that make up all higher organisms (protists, plants, fungi, animals)) have been hypothesized to involve an archaeal cell internalizing a formerly free living alphaproteobacterium. PF threads on this are here and here. Japanese researchers have isolated...
  30. Manasan3010

    I Exploring the Physics of Photoelectric Cells: Electrons, Energy & Color

    In this article, writer says that when atom is hit by photon it gets excited and expelled out of atom and this can be used to form images. My questions are: Why didn't the electrons get to a higher energy level, instead of getting knocked out? How do we find the color(frequency of wave) using...
  31. J

    Could living things survive on radioactive energy?

    Godzilla II was shown last month. I watched Godzilla I again. They explained that when Earth was still radioactive, these creatures evolved so their cells could use radioactivity as power source. Do you know of the schematic because I want to understand how the radioactivity can avoid destroying...
  32. Asuratyr

    I Can red blood cells be considered colloids? (soft matter physics)

    Hi, I was studying soft matter physics when a question arose between a friend and me. Namely if red blood cells can be considered to be a colloid. Colloids as it was presented to us had 3 criteria: high diffusion so the particles wouldn't form a sediment, a small reynolds number and a surface...
  33. PainterGuy

    Understanding DRAM Refresh Operations

    Hi, Could you please help me with the questions below? All of the questions are related to each other. Thank you. Question 1: Please have a look on this attachment. The following text is from the parts highlighted in yellow in attachment. "Dynamic memory cells store a data bit in a small...
  34. T

    Stem cells question and gum lift/gum grafting

    do gum stem cells exist for 100% regeneration of my gums and do stem cell teeth treatment exist as well?what is a gum lift and what does it do for the human mouth? what does gum graphting do? I had asked this in a dentistry forum and its been a year or over 2 months with no response from them so...
  35. BillTre

    Did Neurons Evolve from Secretory Cells?

    People in this Science magazine news article argue yes. The idea that the neuron cell type was in some way derived from secretory cells has been around for a while (1970's at least). The new findings involve finding similarities in how nerve cells and particular secretory cells shared an...
  36. BillTre

    Alzheimer’s May Involve Modified Genes in Brain Cells

    Brain cells from Alzheimer's patients have been found to have modifications of the amyloid precursor protein gene which forms plaques in the brains of people with Alzheimer’s disease. The modifications were duplications, partial deletions, and changes in sequence. This can result in multiple...
  37. E

    B Solar cells - how do they repeat the process?

    Hey everyone, I have to do this presentation about solar cells and how they work. I've been doing a lot of research, and now I know a lot about how they work. However there is just one thing, that I can't understand. So in a solar cell there is an N-type and P-Type. The N-type has too many...
  38. Asmaa Mohammad

    Degeneration of injured cells: granules in cloudy swelling

    Hello, I am doing a pathology course this year, and while reading about reversible injury of cells (degeneration), i came across this part related to cloudy swelling of cells when injured: 'The cell is swollen and the cytoplasm appears granular.' I understand why cells swell, but can't get...
  39. alantheastronomer

    What brain cells does glioblastoma affect?

    Does glioblastoma, as the name suggests, affect only glial cells, or does it also impact neurons as well? Why does it spread so rapidly and effectively? And what modifications need to be done to the Zika virus to make it more effective at battling it?
  40. A

    Atoms in Living vs. Dead Cells: A Comparison

    I want to know what is the difference in atoms when a cell is alive and after it is dead
  41. I

    Do certain cells do better than others?

    I was wondering about the discrepancies between how well individuals cells "perform" within a multicellular organism. For example, all the muscle cells in my right arm, are they all being coded to be "exactly the same", or at least more or less the same based on where they land? But will each...
  42. S

    Insect Endocrinology: How Similar are Insect and Human Nerve Cells?

    It's easy to find descriptions of how the nervous systems of species differ in the organization of nerves, but are there any important differences in the individual cells? For example, are the individual nerve cells of insects similar to individual nerve cells of humans?
  43. Mayan Fung

    Degradation of crystalline silicon solar cells

    Hi there, it is commonly accepted that the lifespan of crystalline silicon solar cells is about 20-30years. And they define the lifespan as when the solar cells efficiency drop to about lower than 10%. However, what are the possible reasons for the degradation? I can only find research papers...
  44. Fullmetal_Potato

    Effects on the body if cells can't divide

    This is for a story I'm writing that involves supernatural abilities though i often try and find some grounded effect of what would happen. One of these abilities causes the cells in a target's body to be unable to divide, replicate, regenerate, etc. I'm curious as to what the effects would be...
  45. José Ricardo

    Medical Red blood cells can turn into a sperm or an egg?

    With the advances of science, will it be possible to turn red cells into sperm or turn them into eggs to help a man who has lost both testicles or a woman who has lost her ovaries?
  46. Wrichik Basu

    What Role Do Cone Cells and Iodopsin Play in Colour Vision?

    As per Wikipedia, there are three types of cone cells. Quoting Wikipedia: I searched a bit more, and found that there are three different types of iodopsin pigment in these cells. Quoting Wikipedia again: Can you say what reaction occurs for each of the pigments when they are exposed to...
  47. T

    B Why Do We Lose Cell Phone Connection Outdoors Without Buildings or Cars Nearby?

    If Cellular network towers are supposedly divided in cells , like this image , then why do we loose connection even when outdoors and not inside or near any buildings/cars. Also why is it common to see more than 1 cell tower near each other?
  48. chemisthypnos

    Observe pH Damaged Cells Via Microscope?

    For an upcoming research project, I intend to apply different solutions to cultures of cells. How would I determine if the cells are incurring damage from the solutions due to the pH of the solutions as I observe them under my compound microscope?
  49. A

    Why some of our cells cease to divide by mitosis

    Hi, this question has been bugging me off..why some of our cells like heart cells or nerve cells do not divide once they reach the maturity? As we know, our cells constantly divide to replace the old or dead cells so why this happen to these two cells ? And it is true only our nerve,heart and...
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