Post has attachment
Remember the xenomorph from Alien and its extending mouth? Well meet its real life counterpart the dragonfly nymph.
Post has shared content
Primordial Soup & The Recipe For Life
In 1924, Russian biochemist Alexander Oparin claimed that life on Earth developed through gradual chemical changes of organic molecules, in the "primordial soup" which likely existed on Earth four billion years ago. In his view, the complex combination of lifeless molecules, joining forces within small oily droplets, could assume life faculties -- self-replication, selection and evolution. These ideas were received with considerable doubt, still pertaining today.
Thirty years later, when DNA structure was deciphered, it was realized that this molecule is capable of self-replication, seemingly solving the enigma of life's origin without resort to Oparin's droplets. But critics argued that life requires not only replicators, but also enzyme catalysts to control metabolism. Another 30 years passed before the discovery that RNA, key component in information transfer from DNA to proteins, can also be an enzyme. This is how the concept of "RNA World" was born, whereby life began when the primordial soup gave birth to a ribozyme, which can both replicate and control metabolism.
Despite this doubts lingered, because a replicating ribosome is a highly complex molecule, with negligible probability of spontaneous appearance in the soup. This led to an alternative concept -- mutually catalytic networks, affording the copying of entire molecular ensembles. This idea echoes Oparin's evolving complex combination of simple molecules, each with high likelihood of appearance in the soup. What remained was to generate a detailed chemical model that will help support such a narrative.
Prof. Doron Lancet and colleagues at the Weizmann Institute of Science, Dept. of Molecular Genetics came up with such a model. First, it was necessary to identify the appropriate type of molecules, that can accrete together and effectively form networks of mutual interactions, in line with Oparin's droplets. Lancet proposed lipids, oily compounds that spontaneously form the aggregated membranes enclosing all living cells. Lipid bubbles (vesicles) can grow and split much like living cells. This is how Lancet generated the concept "Lipid World" two decades ago.
To analyze the invoked molecular networks, they have used tools of systems biology and computational chemistry, that allow instilling rigor into the somewhat ephemeral concept of mutually catalytic networks.
They first address in detail the nagging question of how lipid assemblies can store and transmit information from one growth-split generation to another. They come up with a hitherto rarely explored notion that what gets propagated is compositional information, and show by detailed computer simulations how this happens. Furthermore, they indicate a profound similarity of such composition copying to the way by which growing and proliferating living cells preserve their epigenetic information, that which is independent of DNA replication.
In an article just appeared in the Journal of the Royal Society Interface Lancet and colleagues report an extensive literature survey, showing that lipids can exert enzyme-like catalysis, similar to ribozymes. This s a property crucial for forming the mutual interaction networks. Subsequently, the authors show, using the tools of systems biology and computational chemistry, that the oily droplets can accumulate and store compositional information, and when undergoing fission, transmit the information to progeny.
Based on the computer model they developed, the scientists demonstrated that specific lipid compositions, called "composomes," can undergo compositional mutations, be subject to natural selection in response to environmental changes, and even undergo Darwinian selection. Prof. Lancet comments that such an information system, which is based on compositions and not on the sequence of chemical "letters" as in DNA, is reminiscent of the realm of epigenetics, where traits are inherited independent of the DNA sequence. This lends credence to the scientists' assumption that life could emerge before the advent of DNA and RNA. In their article they in fact delineate a chemical path that lead to the appearance of genetic material in the framework of the oily droplets.
Lancet's "Lipid World" concept is contingent upon the question of whether there were sufficient oil-like "water hating" molecules in the primordial soup. Here too, the scientists describe a comprehensive literature search, according to which there is a high probability for such molecules to be present on early Earth. This conclusion was reinforced by a very recent study showing that Enceladus, one of Saturn's moons, has a sub-glacial ocean (primordial ocean) replete with "water hating" compounds, some of which could form Lipid World-type droplets. Prof. Lancet contends that these findings, along with innovative model-based computations, show that the probability of life's emergence is relatively high, including the exciting possibility that Enceladus presently harbors some early lipid-based life forms.
Post has attachment
Lets look at all the planets , moon and even asteroid that we have landed a probe on ...
https://www.youtube.com/watch?v=IKsUThHEymw
https://www.youtube.com/watch?v=IKsUThHEymw
Post has shared content
A New Form Of Aspirin
“Since its invention in the late 1890s, aspirin remains only one crystal form until 2005. Thereafter, the second polymorph (aspirin II), similar in structure to the form I, was reported,” Dr. Hu said.
“In March of 2012, when examining the crystallization of aspirin from the melt, New York University’s Professor Alexander Shtukenberg discovered the concomitant crystallization of banded spherulites (concentric optical rings) of form I and smooth spherulites of an unknown form.”
“Because of the coexistence of aspirin I and the new form, and the metastablity of this new form at the room temperature, there was a big headache to separate the new form.”
“In addition, we were facing the challenges of obtaining its high-quality diffraction data and determining its crystal structure.”
It took years of setbacks and several collaborations before Dr. Hu and colleagues achieved high yields of aspirin IV and performed its structural analysis.
“After the five-year not-giving-up effort and with a great teamwork using a combination of X-ray powder diffraction analysis and crystal structure prediction algorithms, we solved the crystal structure of the new polymorph,” Dr. Hu said.
The aspirin IV is predicted to dissolve faster than current form I aspirin tablets.
“This faster dissolve rate would mean faster pain relief after ingestion,” the researchers said.
“Greater dissolving efficiency also means that each tablet would require less of the compound.”
Dr. Hu presented the team’s results July 24, 2018 at the 68th Annual Meeting of the American Crystallographic Association in Toronto, Canada.
Post has shared content
Materials scientists from the UCLA Samueli School of Engineering have developed a highly efficient thin-film solar cell that generates more energy from sunlight than typical solar panels, thanks to its double-layer design.
Post has attachment
The $6m question is; what is the name of the shadow effect shown between the head and the door frame?
Post has attachment
Post has shared content
An article published in the journal "Nature Biotechnology" - you can read it at https://www.nature.com/articles/nbt.4229 - describes the proposal of a new taxonomic classification for bacteria based on their phylogenetic similarities. A team of researchers led by Philip Hugenholtz of the Australian Center for Ecogenomics (ACE) used metagenomics to analyze known bacteria and subsequently group them according to their genetic similarities and differences in 99 phyla. The results of this research are available in the Genome Taxonomy Database (GTDB).
Post has shared content
Great minds may think alike, but all minds look alike
The brain is a complex network containing many billions of neurons. Each neuron is connected to thousands of others via links (synapses) which can be strong or weak. A strong link indicates a significant influence between connecting neurons unlike a weak link, which could be tens of thousands of times weaker than a strong one. One of the main challenges in neuroscience is understanding the origin and the possible functional significance of the very wide spectrum of link strengths which is common in all brains. Recently, Israeli physicists led by Prof. Ido Kanter, of the Department of Physics and Gonda (Goldschmied) Multidisciplinary Brain Research Center at Bar-Ilan University, published an article in the journal Scientific Reports in which they demonstrated that learning in the brain is actually conducted by several neuronal terminals (dendrites), contrary to Donald Hebb's 70-year-old theory that learning occurs only in the brain's synapses. The researchers termed their discovery "dendritic learning", and they showed that dendritic learning occurs much faster and in closer proximity to neurons. In a new article, published today in Scientific Reports, the same group of researchers builds upon its previous research to reveal, through advanced computational studies, that dendritic learning leads to the universal phenomenon that all brains are composed of the same wide spectrum of links.
The brain is a complex network containing many billions of neurons. Each neuron is connected to thousands of others via links (synapses) which can be strong or weak. A strong link indicates a significant influence between connecting neurons unlike a weak link, which could be tens of thousands of times weaker than a strong one. One of the main challenges in neuroscience is understanding the origin and the possible functional significance of the very wide spectrum of link strengths which is common in all brains. Recently, Israeli physicists led by Prof. Ido Kanter, of the Department of Physics and Gonda (Goldschmied) Multidisciplinary Brain Research Center at Bar-Ilan University, published an article in the journal Scientific Reports in which they demonstrated that learning in the brain is actually conducted by several neuronal terminals (dendrites), contrary to Donald Hebb's 70-year-old theory that learning occurs only in the brain's synapses. The researchers termed their discovery "dendritic learning", and they showed that dendritic learning occurs much faster and in closer proximity to neurons. In a new article, published today in Scientific Reports, the same group of researchers builds upon its previous research to reveal, through advanced computational studies, that dendritic learning leads to the universal phenomenon that all brains are composed of the same wide spectrum of links.
Great minds may think alike, but all minds look alike
medicalxpress.com
Post has shared content
Rather than dinosaurs, how about decency in the US?
Wait while more posts are being loaded
