[Latin Name] Rhodiola Rosea

[Plant Source] China

[Specifications] Salidrosides:1%-5%

Rosavin:3% HPLC

[Appearance] Brown fine powder

[Plant Part Used] Root

[Particle size] 80 Mesh

[Loss on drying] ≤5.0%

[Heavy Metal] ≤10PPM

[Storage] Store in cool & dry area, keep away from the direct light and heat.

[Package] Packed in paper-drums and two plastic-bags inside.

[What is Rhodiola Rosea]

Rhodiola Rosea (also known as Arctic root or golden root) is a member of the family Crassulaceae, a family of plants native to the arctic regions of Eastern Siberia. Rhodiola rosea is widely distributed  in Arctic and mountainous regions throughout Europe and Asia. It grows at altitudes of 11,000 to 18,000 feet above sea level.

There are numerous animal and test tube studies showing that rhodiola has both a stimulating and a sedating effect on the central nervous system; enhance physical endurance; improves thyroid, thymus, and adrenal function; protects the nervous system, heart and liver; and has antioxidant and anticancer properties.

[Function]

1 Enhancing immunity and delaying aging;

2 Resisting radiation and tumor;

3 Regulating nervous system and metabolism, effectively limiting melancholy feeling and mood, and promoting mental status;

4 Protecting cardiovascular, dilating coronary artery,preventing coronary arteriosclerosis and arrhythmia.

Chemistry playlist: https://www.youtube.com/playlist?list=PL_hX5wLdhf_KyuOalV6rwHjo810Zaa6xq

more at https://scitech.quickfound.net/

Overview of how plastics & synthetic rubbers are made.

Reupload of a previously uploaded film with improved video & sound.

Public domain film from the Library of Congress Prelinger Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).

https://creativecommons.org/licenses/by-sa/3.0/

https://en.wikipedia.org/wiki/Polymer

A polymer is a large molecule (macromolecule) composed of repeating structural units. These sub-units are typically connected by covalent chemical bonds. Although the term polymer is sometimes taken to refer to plastics, it actually encompasses a large class of compounds comprising both natural and synthetic materials with a wide variety of properties.

Because of the extraordinary range of properties of polymeric materials, they play an essential and ubiquitous role in everyday life. This role ranges from familiar synthetic plastics and elastomers to natural biopolymers such as nucleic acids and proteins that are essential for life.

Natural polymeric materials such as shellac, amber, wool, silk and natural rubber have been used for centuries. A variety of other natural polymers exist, such as cellulose, which is the main constituent of wood and paper. The list of synthetic polymers includes synthetic rubber, Bakelite, neoprene, nylon, PVC, polystyrene, polyethylene, polypropylene, polyacrylonitrile, PVB, silicone, and many more.

Most commonly, the continuously linked backbone of a polymer used for the preparation of plastics consists mainly of carbon atoms. A simple example is polyethylene (‘polythene’ in British English), whose repeating unit is based on ethylene monomer. However, other structures do exist; for example, elements such as silicon form familiar materials such as silicones, examples being Silly Putty and waterproof plumbing sealant. Oxygen is also commonly present in polymer backbones, such as those of polyethylene glycol, polysaccharides (in glycosidic bonds), and DNA (in phosphodiester bonds).

Polymers are studied in the fields of polymer chemistry, polymer physics, and polymer science…

Polymerization is the process of combining many small molecules known as monomers into a covalently bonded chain or network. During the polymerization process, some chemical groups may be lost from each monomer. This is the case, for example, in the polymerization of PET polyester. The monomers are terephthalic acid (HOOC-C6H4-COOH) and ethylene glycol (HO-CH2-CH2-OH) but the repeating unit is -OC-C6H4-COO-CH2-CH2-O-, which corresponds to the combination of the two monomers with the loss of two water molecules. The distinct piece of each monomer that is incorporated into the polymer is known as a repeat unit or monomer residue…

https://en.wikipedia.org/wiki/Synthetic_rubber

Synthetic rubber is any type of artificial elastomer, invariably a polymer. An elastomer is a material with the mechanical (or material) property that it can undergo much more elastic deformation under stress than most materials and still return to its previous size without permanent deformation.About 15 billion kilograms of rubbers are produced annually, and of that amount two thirds is synthetic…

Natural vs synthetic rubber

Natural rubber, coming from latex, is mainly poly-cis-isoprene containing traces of impurities. Although it exhibits many excellent properties, natural rubber is often inferior to synthetic rubbers, especially with respect to its thermal stability and its compatibility with petroleum products.

Synthetic rubber is made by the polymerization of a variety of petroleum-based precursors called monomers. The most prevalent synthetic rubbers are styrene-butadiene rubbers (SBR) derived from the copolymerization of styrene and 1,3-butadiene. Other synthetic rubbers are prepared from isoprene (2-methyl-1,3-butadiene), chloroprene (2-chloro-1,3-butadiene), and isobutylene (methylpropene) with a small percentage of isoprene for cross-linking. These and other monomers can be mixed in various proportions to be copolymerized to produce products with a range of physical, mechanical, and chemical properties. The monomers can be produced pure and the addition of impurities or additives can be controlled by design to give optimal properties. Polymerization of pure monomers can be better controlled to give a desired proportion of cis and trans double bonds…

The late British biologist John Maynard Smith (1920-2004) is famous for applying game theory to the study of natural selection. In 1973 Maynard Smith formalised a central concept in game theory called the evolutionarily stable strategy (ESS). His ideas, presented in books such as ‘Evolution and the Theory of Games’, were enormously influential and led to a more rigorous scientific analysis and understanding of interactions between living things. [Listener: Richard Dawkins]

TRANSCRIPT: [RD] George Williams ends his 1975 book about sex in pessimistic vein, suggesting that he can understand sex for those animals which he calls high fecundity, but for low fecundity animals like us, he more or less throws up his hands in despair and says, ‘Well, it’s just a frozen accident. Once it’s… once you’re stuck with sex, you can’t get rid of it.’ Do you think that’s what happened with, say, mammals, I mean are we stuck with sex because we just can’t get rid of it?

Well, I think it’s very possible. I do remember attending a meeting on parthenogenesis in Scandinavia, this must have been 20 years ago or so now. And I wrote in ‘News and Views’ for Nature, when I came back, just describing the meeting, as one sometimes does. I commented that we had recognised at this meeting that there were two major taxa which, as far as we knew, were never parthenogenetic. One are mammals, and I’m ignoring the one observed, or one claimed observed case, because I’m not entirely convinced.

[RD] You mean Jesus Christ or Dolly the sheep?

Oh, Dolly the sheep is fine, no, I was meaning Jesus Christ. I think the evidence in the case of Dolly the sheep is fairly good. But… the other actually, one are the mammals, the other actually is the conifers. There are no parthenogenetic conifers, so far as I know. Almost the next week, there appeared in Nature a letter saying, ‘How can Maynard Smith be so ignorant as to not to know why mammals were never parthenogens.’ And quoting this curious phenomenon of so-called imprinting of genes, the evidence is that in mammals, a few genes, it’s not most of them but just a small number of genes, are labelled, in a sense, as to whether they came from father or mother, in the foetus, and it’s called imprinting, you know, a little stamp saying, ‘I came from mother.’ And in some tissues, only mother’s gene is active and the gene from father is not, and in other tissues, only father’s gene is active and mother’s is not. And I think, actually, David Haig has now given us a very nice evolutionary explanation as to why this imprinting works the way it does, but that certainly wasn’t known in those days. But given that that’s true, for the foetus to develop properly it must have one father and one mother, at least. If it hasn’t got a father then the father’s gene tissues fail and vice versa. I felt a little cross about this complaint because the data hadn’t at that time, about imprinting, had not even been published, so the fact that I didn’t know it seemed to be excusable. It was some years later, actually, that I discovered why conifers are not parthenogens, it’s much more obvious. I was reading a review about the inheritance of chloroplasts and mitochondria in plants, and it turns out that in the coniferous plants, the chloroplast is inherited through the pollen grain. And, clearly, if you don’t have a pollen grain you’re not going to have a chloroplast, you’re not going to grow. Now, I’ve called these things sexual hang-ups, but… you call them frozen accidents, I think it’s basically the same idea; that if a group has been sexual for a long period of time, then other, quite secondary, and in some ways quite trivial, secondary adaptations may be attached on to the male-female differentiation, and once that’s happened, the reverse mutation may be exceedingly difficult. And… I’m inclined to think that mammals… we don’t get parthenogenetic mammals because of sexual imprinting, we don’t get parthenogenetic conifers because of the enhancement of chloroplasts.