26 posts · 15,125 views
Honestly, my blog is a potpourri of biology, medicine, physics, computers and electronics. Loving science as a whole is my strength (and weakness too).
Physiology physics woven fine
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- January 18, 2010
- 12:40 PM
- 202 views
Mirror Neurons: Resonant Circuitry in Brain?
by AmiyaSarkar in Physiology physics woven fine
Back in the time of the “black and white” motion picture days, when “talkies” weren’t even born, we still could make out the essence of what Charlie Chaplin had to “say”. We understood his unspoken words, courtesy a system of neuronal networking, called the mirror neuron system. Another example: you observe a man kissing ‘his’ girlfriend, ‘your’ neuronal network that would otherwise activate when you ‘actually’ kissed her, would fire! Mirror neurons are at work. Seems t........ Read more »
Iacoboni M, Molnar-Szakacs I, Gallese V, Buccino G, Mazziotta JC, & Rizzolatti G. (2005) Grasping the intentions of others with one's own mirror neuron system. PLoS biology, 3(3). PMID: 15736981
- November 16, 2009
- 08:42 AM
- 329 views
A Tale of a Microprocessor, RISC and a Few Loops of miRNA
by AmiyaSarkar in Physiology physics woven fine
The word ‘microprocessor’ is generally used to designate VLSI and SLSI (Very/Super Large Scale Integrated circuits) devices which accept, decode and execute instructions presented in binary coded forms. They may be called the heart of the computer. RISC (Reduced Instruction Set Computer), on the other hand, is a type of microprocessor architecture that uses a simplified, yet highly-optimized set of instructions to deliver good performance. However, like ‘cell’ and ‘nucleus’, they too........ Read more »
Saumet, A., & Lecellier, C. (2006) Anti-viral RNA silencing: do we look like plants ?. Retrovirology, 3(1), 3. DOI: 10.1186/1742-4690-3-3
- October 18, 2009
- 11:22 AM
- 249 views
Metallica Goes The Stem Cell Way
by AmiyaSarkar in Physiology physics woven fine
I had previously written a little about stem cells. While researchers still don’t yet know exactly how the four factors transform the fully differentiated fibroblast cells back into pluripotency, possible explanations are pouring in.Pluripotency (by which the stem cell may become any tissue; muscle or nerve, for example) and “self renewal” (cells should not only differentiate, some ready stock of stem cells must be there for future need) are important determinants for stem cells.According ........ Read more »
Okita, K., Ichisaka, T., & Yamanaka, S. (2007) Generation of germline-competent induced pluripotent stem cells. Nature, 448(7151), 313-317. DOI: 10.1038/nature05934
- August 16, 2009
- 03:12 AM
- 283 views
Of Twinkling Nanostars and the Possible Application of Stroboscopes in Biological Imaging
by AmiyaSarkar in Physiology physics woven fine
Imagine a strong crowd, as you see in a Manchester United versus Liverpool football match and you wished to concentrate on a particular person. How would you do it? Make him wear a fluorescent shirt and dye his hair (don’t do it in the middle of the crowd, I can’t guarantee your safety).Purdue University researchers have been successful in focusing at the cell of interest among a background of equally noisy and boisterous biomolecules and other metabolically active cells. Currently, research........ Read more »
Wei, Q., Song, H., Leonov, A., Hale, J., Oh, D., Ong, Q., Ritchie, K., & Wei, A. (2009) Gyromagnetic Imaging: Dynamic Optical Contrast Using Gold Nanostars with Magnetic Cores. Journal of the American Chemical Society, 131(28), 9728-9734. DOI: 10.1021/ja901562j
- August 13, 2009
- 12:35 PM
- 379 views
The Versatile GABAa Chloride Channel Receptor Complex
by AmiyaSarkar in Physiology physics woven fine
In today’s industrialized society we are constantly exposed to work related stresses. Consequently, anxiety and insomnia (sleeplessness) have become quite common. No wonder, we are using anxiolytics and sedatives more often; to get relief from the anxiety and insomnia respectively.Benzodiazepines such as diazepam (Valium), chlordiazepoxide (Librium) can effectively treat anxiety and insomnia. They do so by binding with a receptor (called Benzodiazepine-GABAa-chloride ion channel complex [hence........ Read more »
Wisden, W., & Stephens, D. (1999) Pharmacology: Towards better benzodiazepines. Nature, 401(6755), 751-752. DOI: 10.1038/44482
- April 5, 2009
- 04:07 PM
- 525 views
Capturing Thought, in Real Time
by AmiyaSarkar in Physiology physics woven fine
Wouldn't it be nice if we mapped how the thought processes traveled across our brain, in real time? That's exactly what Mazahir Hasan et al of Max Planck Institute for Medical Research in Heidelberg, have enabled us to view, when an action potential (AP) is underway in the central nervous system (CNS). The researchers introduced fluorescent calcium indicator proteins (FCIP) into the brain cells of mice by means of viral gene vectors. Each time an AP was underway, a lot of ionic phenomena happene........ Read more »
Hasan, M., Friedrich, R., Euler, T., Larkum, M., Giese, G., Both, M., Duebel, J., Waters, J., Bujard, H., Griesbeck, O.... (2004) Functional Fluorescent Ca2 Indicator Proteins in Transgenic Mice under TET Control. PLoS Biology, 2(6). DOI: 10.1371/journal.pbio.0020163
- April 5, 2009
- 11:00 AM
- 444 views
Brains of Guitarists in Unison Harmonize Too
by AmiyaSarkar in Physiology physics woven fine
During the 80's, I listened to heavy metal bands like Iron Maiden and Metallica, although I couldn't follow their lyrics always. What used to captivate me in awe was how the guitarists synchronized themselves together so well. It apparently seemed as if only one guitar was playing in the background, which on closer scrutiny revealed the actual truth: it was really a duet. It is only now that scientists are beginning to find the secret behind this 'time and phase synchrony'.Scientists at the Max ........ Read more »
Lindenberger, U., Li, S., Gruber, W., & Müller, V. (2009) Brains swinging in concert: cortical phase synchronization while playing guitar. BMC Neuroscience, 10(1), 22. DOI: 10.1186/1471-2202-10-22
- April 3, 2009
- 10:46 AM
- 624 views
An Anatomy of Noise And It's Implications
by AmiyaSarkar in Physiology physics woven fine
Noise is something we dislike, because by definition, noise means unwanted sound. But this definition is subjective, for what is music to my ears (say the heavy metal band Metallica) is noise to most people. In fact Iraqi prisoners were forced to listen to Metallica songs as a means of torture (culture shock and noise) by the American soldiers. Perhaps a better definition is, wrong sound at the wrong place at the wrong time.Apart from acoustic noise; there is visual noise as found in television ........ Read more »
Mori, T., & Kai, S. (2002) Noise-Induced Entrainment and Stochastic Resonance in Human Brain Waves. Physical Review Letters, 88(21). DOI: 10.1103/PhysRevLett.88.218101
- March 20, 2009
- 01:11 AM
- 464 views
Peripheral Clocks Synch With The Master Zeitgeber
by AmiyaSarkar in Physiology physics woven fine
In our bodies there are clocks in addition to the Master clock located in the suprachiasmatic nucleus. In computers, there are multiple clocks too, and they are tightly coordinated. For example, Integrated circuits like AV 9155 generate multiple clock frequencies for different portions of a computer (e.g. bus clock, CPU clock, keyboard clock etc.). All these clock frequencies are well regulated, since ICs like AV9155 use 2 quartz crystals (14.318 MHz) which generates of all these frequencies (th........ Read more »
D. Gatfield, & U. Schibler. (2008) Circadian glucose homeostasis requires compensatory interference between brain and liver clocks. Proceedings of the National Academy of Sciences, 105(39), 14753-14754. DOI: 10.1073/pnas.0807861105
- March 20, 2009
- 01:11 AM
- 460 views
Peripheral Clocks Synch With The Master Zeitgeber
by AmiyaSarkar in Physiology physics woven fine
In our bodies there are clocks in addition to the Master clock located in the suprachiasmatic nucleus. In computers, there are multiple clocks too, and they are tightly coordinated. For example,...
[[ This is a content summary only. Visit my website for full links, other content, and more! ]]... Read more »
D. Gatfield, & U. Schibler. (2008) Circadian glucose homeostasis requires compensatory interference between brain and liver clocks. Proceedings of the National Academy of Sciences, 105(39), 14753-14754. DOI: 10.1073/pnas.0807861105
- March 20, 2009
- 12:59 AM
- 435 views
Quantum Biology: The Spooky NanoWorld of Molecules
by AmiyaSarkar in Physiology physics woven fine
We are quite adept in solving numerical problems in our everyday ‘analog world’ using decimal rules developed by us. Digital computers, on the other hand, calculate using binary or Boolean (0, 1) rules, and then convert the result in decimal format with the help of dedicated binary to decimal converter ICs. In the molecular world, calculations ‘happen’ in a strange way.Take for example the case of Fluorescent Resonant Energy Transfer or FRET. Also known as Forster Resonant Energy Transfe........ Read more »
Vasily V Ogryzko. (2008) Erwin Schroedinger, Francis Crick and epigenetic stability. Biology Direct, 3(1), 15. DOI: 10.1186/1745-6150-3-15
- January 28, 2009
- 01:34 PM
- 614 views
Period Concatenation in The Brain, And The Synthesis of Beta 1 Rhythm
by AmiyaSarkar in Physiology physics woven fine
The principles of generation of EEG waves in the brain are still ill understood. Although the general mechanism of cortical dipoles and thalamocortical oscillations behind the generation holds true; there has been speculations that the alpha waves could actually be originating in the heart- the cardiac electromechanical hypothesis, which states that the arterial pulse ‘shocks’ the skull-brain mass (and interacts electrically and mechanically) to oscillate at its naturally resonant frequency ........ Read more »
Mark A. Kramer, Anita K. Roopun, Lucy M. Carracedo, Roger D. Traub, Miles A. Whittington, & Nancy J. Kopell. (2008) Rhythm Generation through Period Concatenation in Rat Somatosensory Cortex. PLoS Computational Biology, 4(9). DOI: 10.1371/journal.pcbi.1000169
- January 19, 2009
- 08:05 AM
- 718 views
Phase Alignment of Neocortical Gamma Oscillations by Hippocampal Theta Waves
by AmiyaSarkar in Physiology physics woven fine
An empty brain is the devil’s workshop, goes the proverb. Actually, the brain is never empty. Even in our deepest slumber, the brain continues to weave waves of electrical rhythms that can be seen with the aid of electroencephalogram or EEG. When we place electrodes on the scalp or on the cortex (inside the skull), and amplify the faint signals via bioinstrumentation amplifier, we can lay our hands on these fluctuating rhythms. (More on the electronics of EEG may be found at the OpenEEG projec........ Read more »
A SIROTA, S MONTGOMERY, S FUJISAWA, Y ISOMURA, M ZUGARO, & G BUZSAKI. (2008) Entrainment of Neocortical Neurons and Gamma Oscillations by the Hippocampal Theta Rhythm. Neuron, 60(4), 683-697. DOI: 10.1016/j.neuron.2008.09.014
- January 11, 2009
- 02:06 PM
- 748 views
Visualizing Viral Kinetics Using Fluorescence and Bioluminescence
by AmiyaSarkar in Physiology physics woven fine
It would be nice if we could see an individual virus particle, a virion, in real time within a mammalian tissue starting from its attachment to the host cell and entry, to its assembly and budding and release. The dynamics of viral production has been studied using computational models by noting the response of the virus to exogenous administration of reverse transcriptase and protease inhibitors. It was noted that a mind boggling 10^10 to 10^11 virions are produced each day by using this mathe........ Read more »
A Asokan, J S Johnson, C Li, & R J Samulski. (2008) Bioluminescent virion shells: new tools for quantitation of AAV vector dynamics in cells and live animals. Gene Therapy, 15(24), 1618-1622. DOI: 10.1038/gt.2008.127
- December 31, 2008
- 11:40 AM
- 320 views
AIDS,Virology and Nobel Prize in Physiology or Medicine 2008
by AmiyaSarkar in Physiology physics woven fine
In the summer of 1981, the United States Centers for Disease Control and Prevention (CDC), reported occurrence of Pneumocystis jiroveci (previously known as P. carinii) pneumonia in five otherwise...
[[ This is a content summary only. Visit my website for full links, other content, and more! ]]... Read more »
Robert C Gallo. (2006) A reflection on HIV/AIDS research after 25 years. Retrovirology, 3(1), 72. DOI: 10.1186/1742-4690-3-72
- December 28, 2008
- 03:19 PM
- 348 views
An Overview of Gene Therapy
by AmiyaSarkar in Physiology physics woven fine
Ashanthi, a four year old girl, was suffering from an immune deficiency disorder called SCID (Severe Combined Immune Deficiency). Due to the lack of a healthy immune system, she was susceptible to...
[[ This is a content summary only. Visit my website for full links, other content, and more! ]]... Read more »
1. Mark A. Kay*,, 2. Dexi Liu, and, & 3. Peter M. Hoogerbrugge. (1997) Gene therapy . PNAS .
- December 9, 2008
- 02:44 PM
- 861 views
Fantastic Fluorescence:Brainbow and The Nobel Prize 2008
by AmiyaSarkar in Physiology physics woven fine
In my childhood, I used to be fascinated by the mysterious glow of fireflies. Later I learned that it was due to a reaction between a substance called Luciferin and an enzyme, luciferase, a phenomenon called bioluminescence. This kind of glow is not limited to land creatures. Creatures living at the bottom of oceans too emit light.Osamu Shimomura of Japan was given the task of isolating the substance which let the marine mollusk Cipridina glow when it was crushed and mixed with water. He succeed........ Read more »
Stuart Cantrill. (2008) Nobel Prize 2008: Green fluorescent protein. Nature Chemistry. DOI: 10.1038/nchem.75
- November 26, 2008
- 12:00 AM
- 828 views
Molecular Basis of Genetic Switch In The Circadian Clock
by Amiya in Physiology physics woven fine
The circadian clock keeps time by switching on and off a genetic switch. The intricacies of the master clock in the hypothalamus is described here.... Read more »
J.-C. Leloup. (2003) Toward a detailed computational model for the mammalian circadian clock. Proceedings of the National Academy of Sciences, 100(12), 7051-7056. DOI: 10.1073/pnas.1132112100
- November 26, 2008
- 12:00 AM
- 822 views
Neural Networking, Alzheimer's Disease and Memory Share a Few Things
by Amiya in Physiology physics woven fine
In the hippocampus, the part of brain that processes memory, has a neural architecture that resembles Hopfield network of artificial intelligence. This LAN like architecture is synchronized with cues from within the brain and outside. The brain thus has some similarities with information theory.... Read more »
E . Menschik. (2003) Neuromodulatory control of hippocampal function: towards a model of Alzheimer''s disease . . Artificial Intelligence in Medicine, 99-121.
E . Menschik. (2003) Neuromodulatory control of hippocampal function: towards a model of Alzheimer''s disease . . Artificial Intelligence in Medicine, 99-121.
- November 26, 2008
- 12:00 AM
- 884 views
Electron Microscopy And Graphene
by Amiya in Physiology physics woven fine
Richard Feynman onced remarked that there's plenty of room at the bottom. Indeed, with the aid of electron microscopy and nanotechnology we have realized this. Here, the mechanisms of electron microscopy and its much awaited substrate, 'graphene' is discussed.... Read more »
John Silcox. (2008) Microscopy: Spot the atom. Nature, 454(7202), 283-284. DOI: 10.1038/454283a
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