• Why do we prefer things that are harmful for our bodies including sugars, carbohydrates and avoid things with beneficial effects like exercise?
    Harmful effects are associated with sweet taste, beneficial effects have no preferred taste. What do you think about?

    We prefer harmful things for us because every cell in our body and in our psyche in general, there are two drive-antipode: Eros and Thanatos. In this case we are talking about an unconscious attraction to death.

  • Jai Ghosh added an answer:
    Can anyone help me to get mitochondrial isolation from tissue in wistar albino rats?

    I want to isolate mitochondia from liver tissue in wistar albino rats.

    Jai Ghosh · Shivaji University, Kolhapur

    There are thousands of papers on mitochondrial isolation from liver of many mammals. Actually it does not matter whether it is albino rats of mice or rabbits etc.

  • Martin Kohlmeier added an answer:
    Why isn’t nutrition a bigger part of conventional medical school education?
    Diet is arguably the single most important preventive measure for healthy aging because it affects the functioning of every organ in the body and is a factor both in the development of disease and in recovery.
    Martin Kohlmeier · University of North Carolina at Chapel Hill

    I sympathize with the sense of urgency and the promotion of a statement drawing attention to the increasing rates of overnutrition, obesity and resulting health problems. However, I suggest coming back to the original question about lacking attention to nutrition education in medical schools. This is a specific problem that can and should be solved, maybe in small steps, as long as it is going in the direction of better education. There are two specific bills pending in the US Congress, the ENRICH ( and the EAT for Health Act ( Both would improve, though incrementally, the state of nutrition education. I am sure there are opportunities for similar legislative or administrative actions in other countries. I suggest to clamor for such specific changes. Get in touch with your representatives, organizations or the media to push for improvement, if you feel strongly about the need for it.

  • Hossein Hassanpoor added an answer:
    What is the physiological or anatomical difference between place cells and grid cells in the hippocampus?

    In the medial temporal lobe,there are specific types of neural cells such as place cells, head-direction cells, grid cells, and boundary vector cells which involved in cognitive map and spatial memory. Hippocampal “place cells” encode the rat’s location within an open environment independently of its orientation and fire in the specific position. The complementary encoding of the orientation, independently of location, is done by “head-direction cells” .I think all of them are pyramidal neurons. So Is there any physiological or anatomical difference between these kinds of cell?

    Hossein Hassanpoor · Amirkabir University of Technology

    Dr. Burgess said:

    "The differences between grid cells and place cells may well be due to their inputs, although some of the stellate cells in layer II of medial entorhinal cortex are probably grid cells, and they have some differences to pyramidal cells."

  • Olga Krizanova added an answer:
    What would be a good option to specifically block the IP3R2 activity?

    We are interested in blocking the calcium efflux from the ER in hepatocytes, and turns out that they express mainly the type 2 of the IP3R. 2 APB may not work because it has more affinity for the types 1 and 3. What would be a good option to block the IP3R2 in these cell?  

    Olga Krizanova · Slovak Academy of Sciences

    We are using siRNA from Dharmacon, efficiency for the IP3R2 is about 70%. Xestospongin C is also an option, although it is not a type specific and moreover, not 100% specific for the IP3 receptors.

  • Hossein Hassanpoor added an answer:
    Is there any specifically exclusive to the hippocampal astrocytes property?
    The Hippocampal astrocytes may have specific property, which other astrocytes in other brain regions do not have it.
    Hossein Hassanpoor · Amirkabir University of Technology

    Dear professor Verkhratsky
    your suggestions are completely right. All cells are important.
    But I think astrocytes have tools for managing the neural system that other cells haven't it. Ca signaling ( local, global and spotty) and secretion of variety substances with different effects on function and performance of other cell (eg neuron) activities, are these tools. This is just a scientific sense.

  • Daniel Guillaume added an answer:
    Can feces can have traces of hormones, which can give clues about oestrus?
    At least in the case of higher mammals
    Daniel Guillaume · French National Institute for Agricultural Research

    All the steroids can be assayed in the dungs. See on pub med publications on rhinoceroses from a German research team. Of course the assay needs an extraction before immuno-assay. This extraction is difficult and induced a high variability. The immune assays are ELISA or RIA with tritium.

  • Matias Javier Monsalves asked a question:
    How important is the dominant or non dominant leg for protein expression in muscle biopsy, in sedentary or active subjects?

    Looking to know how important it is to identify the dominant or non dominant leg in muscle biopsy and protein expression. Will appreciate very much your help and guide. Best Wishes.

  • Psychology of chronic pain, how much of this pain is a habit?

    We are capable of quickly develop habits and I was wondering if there is a component of chronic pain that comes from habit, other than from a physiological trigger?

    Yohannes Woubishet Woldeamanuel · Stanford Medicine

    I think, considering chronic pain as a multi-level change in processing and sensory inputs, habit-forming activities can become a component. For example, pain medication abuse can be regarded as a form of habit-formation. 

    Just my two cents..

  • Erik Maronde added an answer:
    Are there cell signaling simulators that predict the outcomes of changing protein expression levels/function?
    I am looking for both a didactic or simply a useful out-of-workbench tool that one can use to predict or play around modifying key factors in, say, receptor tyrosine kinase metabolic signaling pathways? I know many of these pathways are both cell type- and stimulus-dependent, but it would be useful to have these pathways not just as webmaps of interactomes you see in reviews or industry websites, but also as interactive webs that one can take or perhaps even give to students to play with, and thus better understand the functional relationship between different pathways/proteins. For example, I would like to determine the effect that upregulating Foxo genes, or PKCs, or inhibiting Ras or mTOR would have on migration, or proliferation or lipogenesis? Currently I am playing with just looking at reviews and mapping various interaction nodes and thought-experimenting on changes, but computer-modeling this would be a lot more productive, faster and easier. Anyway, if you know of such website or endeavor or have any thoughts/comments, please let me know. Thanks.
    Erik Maronde · Goethe-Universität Frankfurt am Main

    Dear Yuri,

    thanks for the interesting links! I hope I understand at least a bit what has been done...

  • Abhijit Naskar added an answer:
    What are the physiological mechanisms involved in cognitive impairment?

    What are the physiological mechanisms involved in cognitive impairment?

    The single term that can explain the cognitive impairment is distressed neuronal impulses. Like sleep deprivation disrupts the circadian rhythm which gives birth to an intense imbalance in the release of melatonin, endorphins, dopamine and others. The cognitive process could better be understood by the way of qualia of subjective consciousness. Once a certain subjective qualia is built inside the neuronal circuitry, it can never be erased permanently. The intricate web related to that specific qualia can only be faded by aging, but it doesn't get erased. All the physiological conditions are the results of synchronized neuronal impulses in the steady state alpha EEG brain waves. Abnormal spikes in the EEG can pin-point the region of the brain responsible for cognitive impairment. In worst state, epileptic seizures give rise to the imbalance in cognition. Some studies have shown that good melodies reduce the frequency of seizures and activates the reward centers which ultimate reinstate proper cognition.

    One very crucial impact on the cognitive process is geomagnetic disturbance. Disturbance in the geomagnetic activity influences the cognition process a lot. I refer to my recent publication on this


    During the geomagnetic disturbances schizophrenic attacks, hallucination, depressions (reduced release in dopamine and serotonin), suicide attempts and many other behavioral symptoms occur. Which means, that ultimately, whenever the brain EEG is not in harmony of any kind of spikes occur due any stimulant, it gives rise to cognitive impairment.

    Best Wishes

  • Jacobus De Wet Scheepers added an answer:
    Do you have any knowledge on real time human performance monitoring?

    I am looking for any devices (especially telemetric) that are capable of monitoring real time the human performance (e.g. during running, or roller skating). Any device counts which suitablly monitors pulse, speed, blood lactate, blood pressure etc. For example Team Polar or Polar RC3GPS. Preferably the devices with the more types of data would be better.


    Jacobus De Wet Scheepers · North West University South Africa

    Another type of device to consider is the bluetooth BioHarness from Biopac. Its use is reported in several published articles.

    It measures a variety of variables:

    ECG (raw only - not recorded but may be viewed live)
    Respiration rate (can reportedly reliably detect breath frequencies between 0.05 Hz and 1.66 Hz)
    RR Interval
    Heart Rate
    Skin Temperature
    Vector Magnitude
    Peak Acceleration
    Breathing Wave Amplitude
    X axis acceleration min
    X axis acceleration peak
    Y axis acceleration min
    Y axis acceleration peak
    Z axis acceleration peak
    Z axis acceleration min

    As for blood pressure measurement during such activities - I cannot think of any wearable device that can reliably measure blood pressure under these conditions. The ABPM devices I know of simply do not record BP during  vigorous physical activity.

    On the Bioharness web page there are links to studies validating the use of the device.


  • Eygene Ilich Maevsky added an answer:
    Can one determine the extent of venous blood pooling via increases in skin temperature?
    While recording skin temperatures from the medial anterior thigh/upper arm, increases in skin temperature were associated with orthostatic instability during LBNP exposure. How much pooled blood is needed to raise skin surface temperature by 0.5 degrees Celsius for example? Can you in fact determine venous pooling or vasomotor activity via skin temperature readings? Does anyone have any experience with this method? Is there a blood heat flux formula that anyone has used?
    Eygene Ilich Maevsky · Russian Academy of Sciences

    Eugene Maevsky 

    Perfectly possible to measure and record temperature response using matrix thermal imaging cameras with high resolution

  • Pao Yen asked a question:
    If you are a Lap swimmer for years and yet your health and concentration are deteriorating, what can you do to fix them this Summer?
    Most people do lap swimming for two reasons – No one told them that lap swimming is only good for muscles but bad for all internal organs including skins and bones. Supposedly you want to improve your spine and you only have time to do lap swimming. You may end up with stronger muscles around spine but reduction of bone mass in spine. The 2nd reason is that our skins simply cannot stay under water for too long. Some lap swimmers do have good general health and bone mass because they do other exercises or run many errands besides swimming. The reason is that there is a microcirculation dilemma problem which was found in 2013 when I was trying to find out why some taichi can heal and some cannot. The problem is that microcirculations in internal organs seem to work in the opposite way of that in skeletal muscles, in relation to physical movements and brain control algorithms as described as follows. For instance, when you move, your heart rate will be elevated and blood will be diverted and fed mostly to your skeletal muscle cells. Hence, blood flow to most internal organ cells will be reduced substantially. So, the longer that you move without stopping, the longer your internal organ cells will be starved but still alive. Only when you stop moving completely, your internal organ cells would have a chance to get more blood supply if your heart rate is still high, but it is only for a very short moment after all stress hormones have dissipated (if they are present). Taichi, only at extra slow speed, circumvents this dilemma problem by making your brain see (or think) that you are not moving (allowing capillaries to open up in internal organs) and becomes the most efficient exercise for raising heart rate and sending blood to every nook and cranny during the whole taichi period (usually for 30 minutes). Some stretching exercises (like some static yoga and martial art poses) are quite good too if you know how to maintain a higher heart rate. For the rest of dynamic exercises (including normal speed taichi, dynamic yoga, and swimming), you have to do 30 sets a day (possibly 1 to 2 hours or more) to gain enough blood for your internal organ cells. Why 30 times? It will be explained later.






    Why don’t you modify your swimming pattern to the following format this Summer?




    1. Relax and swim slowly –


    The main point is to elevate your heart rate without releasing any stress hormone. Moreover, you only need to raise your heart rate 20 to 25 ppm above your resting rate and that is all. Beating up the heart too fast is a total waste. Like all exercises, you have to do it 2 hours after a full meal. In this stage, blood and oxygen will go mainly to your skeletal muscle cells.




    2. Stop for 1 to 2 minutes after each lap -


    IMPORTANT: when you stop, you MUST NOT move at all. You may do deep breathing or meditation (not thinking of anything and just relax). In this stage, blood and oxygen will go mainly to your brain and other internal organs (including bones and skins). You should treasure this moment. Then, go back to step 1.




    3. Lap length (pool size) should be at least 20 meters.




    4. 30 laps a day is a good number for sedentary people. This is equivalent to one set of very slow taichi. Active people who do other sports or run many errands (by walking) can cut down the number of laps. Each errand can be counted as 1 lap. As I mentioned earlier, people will get skin problems if they stay in water for too long. So, you may have to cut short the 30 laps and continue with land exercises (or simply walking) in the same start-stop manner. Fyi, for city folks, you may have an advantage if you live in a big house/apartment, work in a big office, or study in a big campus.




    5. After this, you can swim at whatever speed (without stops) and for whatever purposes that you have. You just have to remember that marathon type of swimming for hours will reduce blood supply greatly to your internal organs. So, you should not do it too often unless you are very young or you are very well compensated.




    This start-stop swimming exercise is called the 30-time Start-Stop Interval Training (for brain and other internal organs). Please see attachment below for more details and explanations. This is a new theory which is derived from my new taichi healing theory called Pao’s Law of Exercise, which is based purely on microcirculations. Well, you don’t have to read it now unless you want to know how I came up with the theories and parameters. 




    If you have any chronic health problems from head to toe (or from inside out), why don’t you give it a try for a few weeks and experience the taichi type of healing by yourself. In fact, not many taichi practitioners (after 1956) have experienced the full benefits of taichi healing because they have been doing it too fast ever since the taichi reform in 1956. Some of them (like the taichi teachers) are all right now because they do more than 30 sets a day. But their health could deteriorate very fast once they retire from teaching. Therefore, I still highly recommend people to do the slow form of taichi 30 minutes a day if they can. Coming back to swimming, I just came up with one question - would it be possible for someone to swim extra slow to mimic doing taichi and get the same health benefits? After you read through the Pao’s Law of Exercise, you should be able to understand that it is impossible simply because you are not able to raise your heart rate high enough in this manner. Moreover, you would probably sink and get drowned. Perhaps, you can try deep-sea diving in very slow motion and use the deep-sea water pressure to elevate your heart rate. I don’t know if this can work because I do not swim. But it sure sounds like the hyperbaric chamber treatment which has some healing effects if you do it right.




    If you are willing to try this start-stop swimming method (or other exercises of your own choice), I would like to get some feedback from you later so that I can get a rough idea on what illnesses can or cannot be cured and how long they will take. Mind you, some organ cells (like bone cells) would take months or years to grow enough new cells with normal DNAs because blood vessels don’t reach there directly. Don’t forget to keep a weekly log.




    Caution:  If you are on medications for chronic diseases, you may want to consult your doctors if you need to reduce dosage from time to time. Don’t do it by yourself because some medicines are not easy to be taken off. You may get pretty bad side effects for doing this.






    You are welcome to communicate with me privately, drop me a message with your email address and we can talk off-line.















  • Cahit Nacitarhan added an answer:
    What factors determine the extent of shift made by an antagonist of concentration-response curve to an agonist?
    The extent of shift made by an antagonist
    Cahit Nacitarhan · Akdeniz University

    Could you explain?

  • Kris Willy Gamotin Jain asked a question:
    What are the metabolic activities that the organelles perform in the cell?


  • Miranda Yeoh added an answer:
    Have you tried meditation for stress removal, and what is its effect on your work, teaching and research?
    Meditation has physiological and psychological effects that include reduced respiration rate, decreased heart rate, changes in brain wave patterns, lowered stress, improved emotional well-being, blood pressure and working memory. So, have you tried meditation? What effects have you observed?
    Miranda Yeoh · Kolej Matrikulasi Selangor, MALAYSIA (Selangor Matriculation College)
    Thanks Prof Ljubomir. Dear friends, Please be sure to rest and exercise and do more FISHING and watch World Cup too :) miranda.
  • Nirav M. Desai added an answer:
    Can anyone suggest the best kit for CD-4 and CD-8 estimation?
    I want to estimate CD-4 and CD-8 in the spleen, please suggest an affordable kit for magnetic bead method estimation without using flow cytometry.
    Nirav M. Desai · Cadila Pharmaceuticals Ltd.
    First you will have to get total T cells and then you may use either BD biosciences or R&D system kits for CD4/CD8 cell isolation kits based on magnetic bead. make sure you use kit is specific to animal you are using Good luck
  • Anna-Maria Andersson added an answer:
    Does anybody have empirical evidence showing the approximate age whereby male testosterone peaks?
    We are looking for evidence about when male testosterone level peaks, and if there are Asian and non-Asian comparisons.
    Anna-Maria Andersson · Rigshospitalet
    The shown graph is based on cross sectional data and it most likely under estimates individual longitudinal changes in serum testosterone. Its a difference seen in some populations between cross- sectional and longitudinal data, possibly due to a secular trend in male serum testosterone seen in both us study and in scandinavian studies.
  • Viatcheslav V. Nesterov added an answer:
    What potential and/or current corrections should be applied to perforated patch recording?
    What potential and/or current corrections should be applied to perforated patch recording? What about liquid junction potential?
    Viatcheslav V. Nesterov · Friedrich-Alexander Universität Erlangen-Nürnberg
    Ups. Not "Na diffuses freely..." but "K diffuses freely" of course.
  • Jan H Meijer added an answer:
    Could anyone share a sample of ECG + ICG recording from a human subject?
    I am looking for a sample of physiological data with ECG and Impedance Cardiography recordings (dZ/dt) suitable to calculate pre-ejection period in human subjects. I would greatly appraciate if you might provide me with a file in .edf or .adicht (LabChart) format. BTW, has anyone ever used PowerLab with any third-party ICG hardware? I would welcome your feedback.
    Jan H Meijer · VU University Medical Center
    Hi Lukasz, I found your message recently. I have very many recordings, patients and healthy volunteers, all made by our home designed and build impedance equipment, AD-converted by a Powerlab and stored on a computer by Chart v5 in *.adicht format. We published several papers (see my record) on timing in which we prefer the Initial Systolic Time Interval above the PEP. The determination of the Q-point, but especially B-point is difficult. Moreover, nobody knows what the position of the "B-point" should be and different definitions are circulating. If you still wish, I can send you some recordings, and we can discuss the extraction of systolic time intervals from ECG and ICG. There is a website from the international society: and a journal dedicated to bio-impedance:
  • Raid Amin added an answer:
    Is there a non-parametric equivalent of a 2-way ANOVA?
    I have two groups, drug treated vs control, and obtained tissue and made measurements at 5 different time points. A 2-way ANOVA works for some of the variables which are normally distributed, however I'm not sure what test to use for the non-normally distributed ones. Samples size varies but ranges from 7-15 per group at each time point.
    Raid Amin · University of West Florida
    The KW Test is for the one factor case only. In the two factor case, we have limited options available. When one of the two factors is a blocking factor, the we can use Friedman's Test for a nonparametric Randomized Complete Block Design. With a factorial experiment with two (or more factors), I opt for a rank based method that works very well. Some would call it "robust" and not nonparametric, but it explained well in the text by William Conover. I mean the Normal Scores Test that is similar to what originally Van der Waerden proposed as a test with Asymptotic Relative Efficiency of at at least 1. Basically, we map the ordered array of raw data into a standard normal distribution, and we use the corresponding z values, or the normal scores. Among all proposed rank based tests, only this tests has been shown to have an acceptable test for interaction. Main effects tests have no problems for many rank based tests as each main effect is like a one factor case. In SAS, I prefer the BLOM option for the normal scores. I have been using this approach for several years now. I do not know of any other valid options here. A nice plus for this method is making the interpretations of the results much easier since z scores follow a Normal (0,1) distribution, and the differences are expressed in standard errors.
  • Sean Patterson added an answer:
    Why are we experiencing failure of sciatic nerve injury to produce hyperalgesia in rats?
    We've been trying transection, transection with ligation, ligation with 1-4 loops done loose or tight, and selective transection or ligation of the post-trifurcation branches. None of the procedures produce hyperalgesia, quite the contrary. The only significant effect compared to control or sham animals is hypoalgesia on the hot and cold plate tests. The only thing that occurs to me is the use of ketamine in the ketamine/xylazine anesthesia: Swartjes M, Niesters M, Heij L, Dunne A, Aarts L, Hand CC, Kim H-S, Brines M, Cerami A, Dahan A. Ketamine Does Not Produce Relief of Neuropathic Pain in Mice Lacking the beta-Common Receptor (CD131). PLoS ONE, 2013; 8: e71326. Mei X, Wang W, Wang W, Li Y, Zhang H, Wu S, Li Y, Xu L. Inhibiting astrocytic activation: a novel analgesic mechanism of ketamine at the spinal level? J. Neurochem., 2009; 109: 1691-700. Does anyone else have experience of the anesthetic blocking the post-opertavie development of neuralgesia?
    Sean Patterson · National University of Cuyo
    We're finally getting hyperalgesia! I can't say which was the important variable as we changed chow, acquired chromic catgut, made 4 loose ligatures our standard and looked at stance during the plate tests with both hot and cold - so thanks to all for the help.
  • Varun Arora added an answer:
    What is the reality of smoking impacts?
    This question may be strange! reviewing studies (including my studies) did not show smoking to be a good predictor of many diseases as it was supposed.what do you think about?
    Varun Arora · Arun Professional Services, India
    Beneficial effects of nicotine and cigarette smoking Follow this link: Don't curse everything on smoking.It has some positive impact too.
  • Dmitry Fridman added an answer:
    How can I use Di-4-ANEPPS for optical mapping ?
    I use the Action-Potential (AP) dye molecule Di-4-ANEPPS for atria optical mapping. I try to understand the mechanism of action of this molecule. So I understood that Di-4 is fixed in the plasma membrane and don't move. Only the electron cloud will change during Action Potential. The modification of the electron cloud induce a shift of the excitation and emission spectrum : it is the stark effect. The goal is to observe a modification of fluorescence according to the Action Potential so the best is to have an emission filter in one of the 2 slopes of the emission spectrum (between 600 and 670 nm or 700 and 800 nm). In this case a very small modification of the AP lead a high modification of the emission. In a lot of papers the excitation wavelength is around 530nm (green light). My question is why use the excitation wavelength in the slope of excitation spectrum and not at the maximum for Di-4 (480nm)? We can excite at 480nm in order to have the max of molecules excited and use an emission filter in the emission slope in order to detect well the changes in AP. Or maybe I understand nothing and it's another mechanism.
    Dmitry Fridman · Center of Advanced European Studies and Research
    I would always record emission and excitation spectra of your dye in your cells / for your application. I made the experience that both spectra can be different in different cell types with di-8-annepps. for me, it was only a shift of 3nm in emission. Also plot a difference spectrum of the emission at rest and after depolarization. it is important not to forget we ae talking about a ratiometric dye and to record at 2 wavelengths. here an interesting link for you that is worth reading and this one
  • Arbind Kumar Choudhary added an answer:
    Which one is more preferable for blood collection from wistar albino rats by retro orbital or by jugular vein?
    Actually, I want to know which method should be used to collect blood from rats because the jugular vein has to be exposed to collect blood which make rat experience a small trauma and additionally there may be a chance of getting infection on that exposed site. Alternatively retro orbital is very very painful for rats.
    Arbind Kumar Choudhary · University of Madras
    thanks with regards
  • Mudhir Sabir Shekha added an answer:
    What are the best human physiology and cellular physiology textbooks?
    In the future, I have to teach medical students so now I would like to buy some physiology text books... so could you please give me your suggestions about any good text books for teaching
    Mudhir Sabir Shekha · Salahaddin University - Hawler
    For human physiology Human Physiology: From Cells to Systems (Lauralee Sherwood) For cellular physiology the best one ((Cell Physiology Source Book, 4th Edition)) bu Sperilakis
  • Hans J. Ferenz added an answer:
    Are there any animals that typically consume their own urine?
    I am learning that cockroaches don't excrete urine like most animals do, but instead just store it in their fat and to recycle it for later use. So, I was wondering if other animals do anything similar or will actually drink their own urine (other than Bear Grylls, of course).
    Hans J. Ferenz · Martin Luther University of Halle-Wittenberg
    Animals usually regulate their water balance and homoiostasis by urine production (composition, amounts, water content). By drinking urine you (humans) take up salts and you may need even more water to excrete them than you gain from drinking (just like drinking seawater).Some animals ahve very efficient kidneys,can drink seawater and probably would survive by drinking urine .
  • Gregory M Blain added an answer:
    What are the most relevant markers of metabolic-induced muscle damage in exercising humans?
    I'd like to determine the influence of excessive metabolite (including Pi, ADP, H+) and reactive oxygen species accumulation during exercise on the muscular function and specifically on muscle damage. To that end, I plan to perform muscle biopsies as well as blood draws right at exercise termination and at different times during recovery. I'm looking for the most relevant biomarkers of those damages in humans. Does anybody have suggestions?
    Gregory M Blain · University of Nice-Sophia Antipolis
    Thanks Gordon. We will indeed assess force (immediately, 4 hr and 24hr post-exercise) in addition to blood sampling and muscle biopsies.

About Physiology

Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system.

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