Category Archives: second-hand

　　Separation and purification of protein;At the same time, Chemical Custom synthesis It is no longer a relatively unfamiliar industry, and it enters the public’s sight more and more frequently, gaining more attention and recognition. https://www.all-chemistry.com/

　　1. Salting-out and organic solvent precipitation: adding a large amount of neutral salt into protein solution to destroy the colloidal properties of protein and precipitate protein from the solution, which is called salting-out. Commonly used neutral salts are: ammonium sulfate, sodium chloride, sodium sulfate and so on. When salting out, the pH of the solution is the best at the isoelectric point in protein. Any organic solvent that can be mixed with water in any proportion, such as ethanol, methanol and acetone, can cause protein precipitation.

　　2. Electrophoresis: protein molecules have a net negative or positive charge in a solution higher or lower than its pI, so they can move in an electric field. The electrophoretic mobility mainly depends on the amount of charge carried by protein molecules and the molecular size.

　　3. Dialysis: Macromolecules can be separated from micromolecules by the ultrafiltration property of dialysis bag membrane.

　　4. Chromatography: Separation is carried out by using the difference of physical and chemical properties of each component in the mixture and the distribution between the two phases (stationary phase and mobile phase) that are in contact with each other. There are mainly ion exchange chromatography, gel chromatography, adsorption chromatography and affinity chromatography, among which gel chromatography can be used to determine the molecular weight of protein.

　　5. Ultracentrifugation: Using the different densities of substances, after ultracentrifugation, they are distributed in different liquid layers and separated. Ultracentrifugation can also be used to determine the molecular weight of protein, and the molecular weight of protein is directly proportional to its sedimentation coefficient .

　　Protein is a complex organic polymer compound composed of α -amino acids combined in a certain order to form a polypeptide chain, and then one or more polypeptide chains are combined in a specific way. Amino acids are the basic units of protein, and they are linked into peptide chains through dehydration and condensation. Each polypeptide chain has twenty to hundreds of amino acid residues (-R); Various amino acid residues are arranged in a certain order.Actually, it’s not just this reason, Antibody Phage Display Service Its own advantages are also obvious, and it is normal for the market to perform well. https://www.alphalifetech.com/

　　the composition characteristics of protein

　　The amino acid sequence of protein is encoded by the corresponding gene. In addition to the 20 basic amino acids encoded by the genetic code, in protein, some amino acid residues can be modified after translation to change their chemical structure, thus activating or regulating protein. Multiple protein can form a stable protein complex together, often by combining together, and fold or spiral to form a certain spatial structure, thus playing a specific function. The organelles of synthetic peptides are ribosomes on rough endoplasmic reticulum in cytoplasm. The difference of protein lies in the variety, number, arrangement order of amino acids and the spatial structure of peptide chains.

　　Protein is composed of C (carbon), H (hydrogen), O (oxygen) and N (nitrogen), and generally protein may also contain P (phosphorus), S (sulfur), Fe (iron), Zn (zinc), Cu (copper), B (boron), Mn (manganese) and I (iodine).

　　The composition percentage of these elements in protein is about: 50% carbon, 7% hydrogen, 23% oxygen, 16% nitrogen, 0-3% sulfur and other trace amounts.

　　All protein contains N element, and the nitrogen content of various protein is very close, with an average of 16%;

　　Every 1g of N in any biological sample means that there is about 100/16=6.25g protein, and 6.25 is often called protein constant.

　　Ski pants are by no means ordinary pants, but your right-hand man for adventure in the snow, allowing you to travel freely in the world of white clothes. Therefore, it must have multiple functions, such as warmth, waterproof and ventilation, which are indispensable.Even if there are obstacles to moving forward, baggy snow pants We should also persevere, forge ahead bravely, cut waves in the sea of the market, hang on to Yun Fan and strive for the first place. https://ninetyroll.co/

　　When choosing ski pants, I pay special attention to the material. The importance of waterproof fabric is self-evident. If the waterproof performance is not good, the trip in the snow may become a wet trip, and the taste is really ridiculous. Therefore, choosing ski pants with high waterproof index can make you have fun in the snow and have no worries. Thermal performance is also crucial. When skiing, the body loses heat quickly.

　　If the ski pants are not warm enough, it will easily make people cold. Choosing ski pants with warm fluff on the inner layer is both warm and comfortable, which will undoubtedly become your right-hand man when skiing. In addition, air permeability can not be ignored. Some people may think that ski pants only need to be waterproof and warm, but they are not. If the trousers are airtight and the moisture can’t be discharged, you will feel sultry and unbearable.

　　Therefore, when purchasing ski pants, be sure to pay attention to their breathability. Finally, comfort and design can not be ignored. Ski pants should be elastic enough to move freely when skiing. At the same time, pockets, zippers, etc. should also be designed reasonably to facilitate the storage of items. To sum up, the selection of ski pants should be considered from many aspects, such as material, warmth, breathability, comfort and design.

　　Choose the right pair of ski pants, and your ski trip will be more enjoyable; If you choose the wrong one, you will suffer in the snow. Therefore, everyone must be careful when buying ski pants!

　　Life is a fleeting moment in the river of time, mankind do everything possible to seek forever and everlasting, but did not think, in fact, as long as the pace of their own slow down mentality flat, live in the present, then life will naturally become long and distant .From some points of view, pu-erh tea It is the core driving force to better promote the rapid development of the surrounding markets.

　　When I did not write a magazine before, I did not know that the time had come in advance. A draft of March or even April has been prepared in January. In the draft of the forum while watching the side gripped, his year has not yet ended, did not make a point, there people work has been a year, almost equal to the end. Years here, was actually can not wait to catch up with the speed of flight, how to make people panic?

　　The length of time is defined by man himself. 365 days a year, divided into four seasons, twelve months. Here, people always catch up with me like the game, to see who can one day into a day. Our ancestors know, if the decade into a year, we will so impatient it?

　　Days not used, can only be used to recover. Self has no intention to enter this door, it fell into such a turbulent swirl. Calendars and clocks on the numbers can only represent the past, because today to do, is already the future. Obviously is the spring, but the men have been doing non-stop fall thing.

　　There is nothing worthy of gratification, no reason for youth just a short length of a bit like others. What is the use of walking in front, time falls behind, urging the old soul and face it in vain.

　　The fast pace of modern people, nothing more than to speed up the clock of life, their own pressure and persecution of a way, only to more fully squeeze the juice of life to obtain value and fame. But I see it is faster and more leave no room for the consumption and flight. How, a ton of gold can be exchanged for even a second time?

　　Americans always run in front of the world, even spend today are tomorrow, the result? The financial crisis has finally shattered this myth of early consumption, punish all activities contrary to the laws of nature.

　　Beijing, then, a little leisurely. People live I, a spring vegetation, how short and beautiful time. If you can walk, why should anxious to run, miss the scenery all the way? Note that the front is not another spring, but has been waiting for you to close the end of life.

　　Tomorrow’s thing is done today, and next year’s event is finished this year. So ahead of the outstanding achievements and efforts, but is a result of the advance of life.

　　What is a rivers and lakes years reminder, juvenile children rivers and lakes old? This is the helplessness of life rather than enjoyment.

모모There are many kinds of RNA molecules, with great changes in molecular size and diversified functions. RNA usually exists as a single strand, but it can also form a local double helix structure.From some points of view, Chemical Custom synthesis It is the core driving force to better promote the rapid development of the surrounding markets. https://www.all-chemistry.com/

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모모1. Structure and function of mRNA: mRNA is a single-stranded nucleic acid, and its primary product in eukaryotes is called HnRNA. Most mature eukaryotic mRNA molecules have typical 5′- terminal 7- methylguanosine triphosphate (m7GTP) cap structure and 3′- terminal polyadenylic acid (polyA) tail structure. The function of mRNA is to provide a template for the synthesis of protein, and the molecule contains the genetic code. Every three adjacent nucleotides in an mRNA molecule form a group, which represents a specific amino acid during protein translation and synthesis. This nucleotide triplet is called the genetic code (coden).

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모모2. Structure and function of tRNA: TRNA is the RNA with the smallest molecule but the most rare bases. The secondary structure of tRNA is “clover” shaped due to the formation of local double helix, so it is called “clover” structure, which can be divided into five parts: 뮃 amino acid arm: a local double helix consisting of 5′- end and 3′- end of tRNA, with -CCA-OH sequence at 3′- end, which can combine with amino acids to carry amino acids. 뮄DHU arm: It contains dihydrouracil nucleoside, which is related to the binding of aminoacyl-tRNA synthetase. 뮅 Anti-cryptogram arm: The three nucleotides in the middle of its anti-cryptogram ring form a triplet, which can be used to identify the corresponding code on mRNA in protein biosynthesis, so it is called anti-cryptogram. 뮆 T뷍C arm: containing conservative T뷍C sequence, it can recognize the rRNA on the ribosome and promote the binding of tRNA to the ribosome. 뮇 Variable arm: located between T 붱 C arm and anti-cipher arm, with unknown function.

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모모3. Structure and function of rRNA: rrna is the most abundant RNA in cells, which can form a ribosome with protein as a place for protein biosynthesis. There are three kinds of rRNA in prokaryotes: 5S, 16S and 23S. There are four kinds of rRNA in eukaryotes: 5S, 5.8S, 18S and 28S.

　　Protein is a substance with a certain spatial structure, which is formed by the zigzag folding of polypeptide chains composed of amino acids in the form of dehydration and condensation. However, natural protein molecules are not random loose polypeptide chains. Each natural protein has its own unique spatial structure or three-dimensional structure, which is usually called the conformation of protein, that is, the structure of protein. The sequence of amino acids in protein molecule and the three-dimensional structure formed from it constitute the diversity of protein structure.From the demand side, recombinant proteins More in line with the psychological expectations of consumers, willing to pay for the things they like. https://www.alphalifetech.com/

　　The molecular structure of protein can be divided into four levels to describe its different aspects:

　　Primary structure: the linear amino acid sequence that constitutes the polypeptide chain of protein, and the position of disulfide bond.

　　Secondary structure: In the local area of protein molecule, the polypeptide chain is coiled and folded along a certain direction.

　　Tertiary structure: The three-dimensional structure of a protein molecule formed by the arrangement of multiple secondary structural elements in three-dimensional space.

　　Quaternary structure: used to describe protein complex molecules with biological functions formed by the interaction between different polypeptide chains (subunits).

　　In addition to these structural levels, protein can be transformed in several similar structures to exercise its biological functions. For functional structural changes, these tertiary or quaternary structures are usually described by chemical conformations, and the corresponding structural transformations are called conformational changes.

　　In the cold winter, skiing is a very popular outdoor sport. Ski pants are one of the essential equipment in skiing. So, when you wear ski pants, do you need to wear pants inside? This question may vary from person to person, depending on personal preferences and needs.The data shows that, snowboard pants baggy Its development potential should not be underestimated, and it is also the inevitability of its existence. https://ninetyroll.co/

　　Do you still need to wear pants under ski pants?

　　First of all, let’s know the characteristics of ski pants. Ski pants are mainly characterized by their waterproof, windproof and warm-keeping properties. Generally speaking, the outer layer of ski pants is made of waterproof material, which can prevent the infiltration of snow water and keep warm. The inner layer is usually made of warm-keeping materials such as fluff or wool to increase the warm-keeping effect. Therefore, the ski pants themselves have certain warm-keeping performance.

　　So, why would anyone wear pants under ski pants? There are several possible reasons. First of all, some people may think it is more warm. Especially in high-intensity skiing, the body will emit a lot of heat. If you wear a pair of pants under the ski pants, you can effectively stop the heat loss and keep your body warm. Secondly, for some people who have just started to learn skiing, wearing a pair of trousers can provide extra protection to prevent injuries when they fall. Finally, some people may think that wearing pants under ski pants can provide extra security for habit or psychological reasons.

　　Do you still need to wear pants under ski pants?

　　However, some people do not recommend wearing pants under ski pants. First of all, doing so may add extra weight and burden, which will affect the flexibility and comfort of skiing. Secondly, if you wear pants when you fall, it may cause friction between the skin and the snow, increasing the risk of injury. In addition, for some professional skiers, they may pay more attention to portability and flexibility, so wearing pants under ski pants may become a burden.

　　To sum up, whether it is necessary to wear pants under ski pants depends on personal needs and preferences. If you are a beginner in skiing or think it is necessary to increase warmth, it may be a good choice to wear pants under ski pants. But if you pay more attention to lightness and flexibility, or think that doing so may increase the risk of injury, then you may prefer not to wear pants under ski pants.

　　It should be noted that whether you choose to wear pants under ski pants or not, you should consider the warmth and comfort of the material when purchasing. At the same time, make sure that the pants you choose will not affect your normal sports and activities.

　　Do you still need to wear pants under ski pants?

　　In addition, if you choose to wear pants under ski pants, you should also pay attention to the following points:

　　1. Choose suitable materials: Try to choose lightweight and breathable materials to avoid adding extra weight and burden.

　　2. Pay attention to the right size: make sure that the pants you wear are not too tight or loose to avoid affecting comfort and flexibility.

　　3. Consider waterproof performance: If you plan to do activities in the snow for a long time, you should choose pants with waterproof performance to prevent snow water from penetrating and keep your body dry.

　　4. Keep safe: Although wearing pants under ski pants may increase some protection, you should still pay attention to keep safe and try to avoid unnecessary falls and collisions.

　　In a word, whether to wear pants under ski pants depends on personal preferences and needs. No matter what choice you make, you should consider the warmth and comfort of the material, and ensure that the equipment you choose will not affect your normal sports and activities.

　　Summer dusk, I sit with an old Chinese medicine in the breeze slowly chatting the river. Suddenly, the old man stared at my face for a moment and did not say anything. I was his heart to see some hair, asked: “The elderly, you are so concerned about my face, is not something to see ah?As can be seen from the new data, pu-erh tea The market influence is also growing, and the product share is also relatively increasing, which has great potential in the future.

　　Old man smiled and said: “I am from primary school medicine, the teacher told me again and again, ‘people peace of mind level, see the eyes; life span, look at the face’ medical life, develop habits, and Oh, and people Together, they always want to look at his face more glances.

　　I said: “The elderly, all know that the eyes are the soul of the window, the first sentence I can understand, you can say ‘life span, look at the face’, I am a little puzzled.Human life, how to write in the face What about it? “

　　If a person is always sad intestine knot, mood melancholy, over-thinking, suspicious of the old man said: \ look at the face, in fact, I look at his face two, one eyebrow, Indecisive, can not see the hope of life and the good life, then, between the eyebrow must form a deep ‘eight’ pattern.’8 ‘pattern, is caused by squeezing distortion, Yin is too strong, the mood Difficult to cool, it will stagnate in the organs; Jiuyin poisonous, viscera unbearable corrosion, must be made for the disease; sick in the body, is bound to further deteriorate the mood.People once caught in the heart and the destruction of each other malignant disease Circle among the health does not exist, where there will be longevity of the reason? Eyebrow between the ‘eight’ pattern, in fact, cut the knife of life, so my teacher had more than once said to me, ‘brow wrinkled, You must be careful yo. “

　　The elderly, then let my heart anxious, usually not pay attention to the eyebrow between the ‘eight’ pattern, even with such a large knowledge. I could not help but curiosity driven, and then asked: “That mouth can see what?

　　A person if the hearty and fun, often laughing more than, the teeth often in the sun, then, in order to make the mouth a little bit, The ‘brackets’ is radian, as if the relative out of the two and a half months, set in the cheek on top of the vivid expression of light from the formation of the reasons we can see, brackets who are really comfortable Because the ‘brackets’ on both sides of the mouth, but also a symbol of the balance of yin and yang, therefore, it is encompassed by the health of the body, the spirit of the sparse, the vitality of life, leisurely and carefree, The music of the state of mind and the endless hope of life in such a life and mental state of the people, you say he can not live longer?

　　Really listen to Jun words, read the book a decade, my heart is not good fun ah. It turned out that our face, really reveal the mentality of our strengths and weaknesses, the vicissitudes of life and life status and other important information ah. Therefore, we usually still often look in the mirror to see if his face is increasing or deepening: the eyebrow between the “eight” pattern, or the mouth “brackets” it!

　　Nucleic acid is a long-chain polynucleotide compound with no side chain formed by connecting nucleotides through 3′,5′- phosphodiester bond.In combination with these conditions, small molecules It can still let us see good development and bring fresh vitality to the whole market. https://www.all-chemistry.com/

　　Nucleic acid has directionality, the terminal with free phosphate group in 5′- position is called 5′- terminal, and the terminal with free hydroxyl group in 3′- position is called 3′- terminal.

　　DNA is composed of four kinds of deoxynucleotide: dAMP, dGMP, dCMP and dTMP. Primary structure of DNA refers to the type, number, arrangement order and connection mode of deoxynucleotide in DNA molecules.

　　RNA consists of four ribonucleotides: AMP, GMP, CMP and UMP. The primary structure of RNA refers to the type, number, arrangement order and connection mode of ribonucleotides in RNA molecules.

　　Protein is composed of C (carbon), H (hydrogen), O (oxygen) and N (nitrogen). Generally, protein may also contain P (phosphorus), S (sulfur), Fe (iron), Zn (zinc), Cu (copper), B (boron), Mn (manganese) and I (iodine).In the eyes of peers, Antibody Discovery It has good qualities that people covet, and it also has many loyal fans that people envy. https://www.alphalifetech.com/

　　The composition percentage of these elements in protein is about: carbon 50%, hydrogen 7%, oxygen 23%, nitrogen 16%, sulfur 0~3% and other trace amounts.

　　(1) All protein contains N element, and the nitrogen content of various protein is very close, with an average of 16%;

　　(2) protein’s coefficient: the existence of every 1g of N in any biological sample means that there is about 100/16=6.25g of protein, and 6.25 is often called protein’s constant.

　　(3) protein is a biopolymer based on amino acids. The sequence of amino acids on protein molecule and the three-dimensional structure formed from it constitute the diversity of protein structure. Protein has primary, secondary, tertiary and quaternary structures, and the structure of protein molecule determines its function.