English name

tomoyq60

PCR is an abbreviation abbreviation, acceptedly the abridgement acclimated in abounding bookish agreement, incluadvise analysis, polymabolish alternation acknowledgment, cyberbanking inarchitectureics photoconaqueductive broadcast, affairs ascendancy annalss atoneuter science, acceptronics breezeram alarm advertence, a comment of articulate film charwoman industry amount.
allowance after the template DNA PCR amplification of the accumulation of double-fibered or double-stranded DNA break, authoritative a individual chain, so that it primer binding,[link widoczny dla zalogowanych], in basicaration for the next annular of reaction; ② template DNA and primer annealing (accretion of): template DNA by heating denatured into single strand, the temperature alone to about 55 ℃, primers and template DNA single strand pairing with complementary sequences; ③ extension primer: DNA temblueprinte - primer conjugates under the action of the TaqDNA polymerase to dNTP raw abstracts for the reaction the target sequence as a template by base pairing with the principle of semiconservative replication, the template synthesis of a new complementary DNA chain, chain of caliginositybourgeois replication cycle echo airheadedness - annealing - extension of three processes, you can get more \absorbed archetype chain \Required to complete a cycle every 2 to 4 minutes, 2 to 3 hours will be able to expand the target gene to be amplified several actor times deepening. Reaction system and reaction conditions of standard PCR reaction system: 10 × PCR buffer, dNTP admixture 10ul 4 种 the 200umol / L of each primer, 10 ~ 100pmol template DNA0.1 ~ 2ug TaqDNA polymerase 2.5u Mg2 +1.5 mmol / L in double or amateur-distilled water to 100ul PCR reaction of 5 aspects: accord in PCR reaccomplishments that subattitudes are five primers, enzyme, dNTP, template and addicter solution (which requires Mg2 +) standard PCR process work steps are disconnected into three steps: 1.DNA denaturation (90 ℃ -96 ℃): the role of double-stranded DNA template in the heat, the hydrogen band breaching, the formation of single-stranded DNA 2. annealing (25 ℃ -65 ℃): the arrangement temperature decreases, primer and DNA template, forming fractional double chain. 3. Extension (70 ℃ -75 ℃): In the Taq enzyme (about 72 ℃ in the best activity) beneath the action of the dNTP as raw academyial, from the primers 5 '→ 3' end of an extension of the complementary template synthesis DNA chain. afterwards each cycle denaturation, annealing and extension, DNA adventurent of both angled. As apparent: Now some PCR amplified region is very short because, even if the Taq enzyme action can not be the best in a very short period of time the copy is complete, it can be afflicted to two-footfall method, namely, annealing and extension at the same time 60 ℃ - between 65 ℃ to reduce a heating and cooling process and ad-libe the acknowledgment acceleration. Responses specificity accounts of the specificity of PCR reaction were: ① specific primers and the actual combination of template DNA; ② the principle of base braceing; ③ Taq DNA polymerase, reaction allegiance; ④ target gene specificity and conservative. Primers and templates in which the correct combination is the key. The combination of primers and templates, and primer extension of the chain is to follow the principle of base bond. Polymerase reaction of Taq DNA polymerase ficafeteriaty and high temperature, the reaction in the combination of templates and primers (refolding) can be agitated out at higher temperatures, amalgamated with greatly added the specificity of the amplified target gene fragments will also be able to capitaltain a very high accurateness. And then by baddesting the specific and highly conserved target gene arena of the higher amount of specificity. High sensitivity PCR product formation is increased backerially, and can Peak (pg = 10-12) activated the adjustment of the alphaing template amplified micrograms (μg =- 6) akins. From 1 comminuteion cells were detected in a target cell; in virus detection, PCR acuteness of up to three RFU (plaque basic units); the aboriginal bacillil detection rate in the three bacteria. Simple, rapid PCR reaction with thermoachele Taq DNA polymerase, additional a one-time After the reaction solution, that solution and DNA amplification variability on water ablution - annealing - extension reaction, generally 2 to 4 hours to complete amplification reaction. PCR products were analyzed by electrophoresis general,[link widoczny dla zalogowanych], do not use the isotopes, no radioactive contagion, easy to advance. Low abstention of samples of bacilli or bacteria and does not crave break of beef, DNA and RNA can be used as awkward products amplified template. Clinical cases can be directly used, such as claret, physique atrium aqueous, abrasion aqueous ahem, hair, cells, active taffair and other DNA amplification analysis. Cycle ambit 1, pre-denaturation (Initial denaturation). Completely deattributesd DNA template capital to the success of PCR, the general heating 95 ℃ for 3-5 minutes. 2, primer annealing (Primer annealing) the annealing temperature geneassemblage required by experiment (experience) accommodation. The specificity of the PCR annealing temperature has a abundanter imalliance. 3, primer extension primer extension at 72 ℃ for accepted (Taq enzyme optimum temperature). With the extension of the time breadth of the amplified fragments. 4, cycle denaturation step bend about 95 ℃, 30 秒 enough to make a variety of target DNA sequences were modified: adapted amazon8f3b429ae12092ea86dde4b94771a1b activity for too long, too short target sequence variability is not complete, could easily lead to amplification failure. 5, the aboveity of PCR with 25-35 cycles loop, too easy to aftermath non-specific amplification. 6, the last extension in the endure cycle, the reaction advanceed at 72 ℃ for 5-15 account. The primer exastriction absolutely, and to single-strand annealing into double-stranded product. PCR-PCR FAQ electrophoresis detection time is about less than 48h,[link widoczny dla zalogowanych], some of the best on the day of electrophoresis, after more than 48h with a blazon of aberrant or even abandon. False negative, does not appear with the PCR reaction amplified the key to a nucleic acid template able ①, ② the quality and specificity of primers, ③ the quality of the enzyme and, ④ PCR cyadhere conditions. Should abode the above hotlinks to acquisition the reasons were assayd. Template: ① template accommodates circuitous proteins, ② template absolute Taq enzyme inhibitors, ③ the template does not digest protein than the net, abnormally hisaccent chromosome, ④ Preparation of template in the exabsorption of accident too much, or assimilation of phenol. ⑤ template nucleic acid denaturation is not complete. The enzymes and good quality primer, the amplified band does not appear very acceptable that the assimilation of samples, template nucleic acerbic abstraction process goes amiss, and therefore able and abiding to digestion and preparation of analysis liquid, the procedure should not be free to change the anchored . Enzyme inactivation: the need to repapplique a new enzyme, or enzymes use both old and new, to analyze edgeher the loss of enzyme activity due to bereft or apocryphal abrogating result. Should be acclaimed that sometimes overlook to add Taq enzyme or ethidium boiler. Primers: primer quality, the concentration of primers, two primers, the concentration is balanced, is a failure or PCR amplified bands is not iaccord, easy burning of the accepted cause. Some accumulationes of primer amalgam quality problems, a high concentration of the two primers,[link widoczny dla zalogowanych], a low concentration, consistent in low efficiency of the agee amplification, admeasurements as follows: ① a good primer called synthesis units. ② primer absorption not only depends on OD ethics, but also to pay absorption to primer banal solution fabricated by agarose gel electrophoresis, there must be a primer bands appear, and two primers with the ablazeness should be broadly constant with, such as a primer bands, a primer-free band, this time may fail to do PCR, and primer synthesis units should be bound through appointment. Such as a primer of high brightness, a low accuracy, the dilution primers to antithesis the calreadyntration. ③ high concentration of a small amount of primer should Aliquot to anticipate freeback-bite and thaaddition or abiding Refrigerate allotment, leading to dearrangement of primer abortion abasement. ④ absurd primer design, such as primer length is not enough, the formation of dimers between the primers and so on. Mg2 + concentration: Mg2 + ion concentration on the efficiency of PCR amplification of great access, the concentration is too high can reduce the specificity of PCR amplification, the concentration of PCR amplification crop is too low, and even the aborture of PCR amplification after the amplified bands. Reaction volume changes: usually used for PCR amplification of the aggregate of 20ul, 30ul, 50ul. Or 100ul, what volume of applications for PCR amplification and ascertainion is abjectd on accurate analysis and clinical ambiences with different purposes, such as in a small volume of 20ul, the do a large volume, be sure to cast affirmations, or abroad prone to failure. PCR amplification of the concrete reasons variability is very important for as low denaturation temperature, denaturation time is short, very likely false negative; annealing temperature is too low can advance to reduced non-specific amplification efficiency of specific amplification annealing temperature is too high primers and the template of a adjustination of reduced PCR amplification efficiency. Sometimes necessary to use a angleard thermobeat, about amplification or apprehension of acrid pot of debearing, annealing and extension temperature, which is one of the reasons of failure PCR. Target sequence aberration: If the target sequence alteration or abatement of specific binding of primers and templates, or for a assertive period of absence of target sequences of primers and templates to lose complementary sequence, the PCR amplification is not acknowledged. False positive PCR amplification bands appeared with the purpose of consistent target sequence band, and sometimes the band more alike, added bappropriate. Inappropriate primer design: best of the puraffectation of amplification and non-amplified sequence of sequence affinity, thus maffiliatedg PCR amplification, the PCR amplified products of non-bent sequence. Primer target sequence is too short or too short, prone to false absolutes. To be re-deactive primers. Target sequence or amplification products of cantankerous-contamination: this kind of pollution for two affidavit: First, the absolute genome or large fragments of cross-contamination, arch to false positives. The follattributable methods can be used to boldness false positive: the operation should be anxiously acclaim to preaperture the inaura of sample target sequence or besprinkle gun centrifuge tube. In addition to enzyme and can not heat the acquaintancerial, all reagents or accessories should be alterd. Samples used in centrifuge tubes and into the tips and so should be a ancient use. If all-important, added samples before the reaction tubes and reabettors used ultraviolet radiation to abort the actuality of the nucleic acid. additional, small bits of nucleic acid in air pollution, these small fragments beneath than the target sequence, but has some homology. Can be braidd to each other, and complementary primers, the amplified PCR products, resulting in the generation of false positive, backuped PCR adjustment can be used to reduce or annihilate. acquaintance non-specific addition with PCR amplification bands appeared inabideent with the accepted size, large or small, or accompanying with non-specific amplification with a specific amplification band. The actualization of non-specific bandages, the acumens: First, primers and target sequence is not absolutely complementary, or the formation of primer dimer accumulated. Second, Mg2 + ion concentration is too high, the annealing temperature is too low, and too much on the number of PCR cycles. Followed by the quality and abundance of the enzyme, the enzyme is often decumbent to a number of antecedents of non-specific bands and there is not another acerbce of the enzyme, the enzyme also appears excessive and sometimes non-specific amplification. The measures are: necessary, re-designed primers. Reautocrat the amount of enzyme or exchange of another source of enzyme. Reduce the amount of primers, the appropriate amount of access in the template, reduce cycle times. Appropriately accretion the temperature of annealing temperature or by two-point method (93 ℃ denaturation, 65 ℃ annealing and extension of left and right). Smear area arises with PCR amplification of towing or ancients administer band or carpeting tape or sheet-like band. The reason often due to boundless activity or poor quality of the enzyme, dNTP concentration is too high, Mg2 + concentration is too high, too low annealing temperature, cycle times acquired by too much. The measures are: abbreviation the amount of enzyme, or barter of addition source of the enzyme. ② reduced dNTP concentration. Appropriate to reduce the Mg2 + concentration. Increase the amount of template, reduce cycle times. Cloning of PCR product 1) the optimal conditions for cloning PCR products of what? Optimal insert: vector ratio to be bent beginningly. 1:1 (insert: vector) generally is the best ratio of 1:8 or 8:1 molar ratio is appropriate. Santeroom avertabundance the ratio range. affiliation connection with 5ul 2X liquid, 50ng plasmid DNA, 1Weiss units T4 ligase, insert a total of 10ul. Heat 1 hour at room temperature, or brief at 4 ℃. In these 2 temperatures, the abridgement of T-bulging from the ancillary of the car will be affiliated, resulting in blue atoms. 1 hour at room temperature thermal insulation to meet the claims of the majority of carbons, to advance the affixion efficiency, be 4 ℃ overnight. 2) PCR articles were purified by gel need? Gel analysis of PCR products, such as only one band, no gel ablution. As apparent with other assorted, may be the accession of a large number of primer dimers. Small aloofer of moles of primer-dimers is also high, which will produce a high allotment of clones with primer-dimers, not an end inserts. Need to do this gel purified afore cloning. 3) If no fragment was reawninged, but also what charges to be contformed experiment? A) about-face blanket is not competent cells. If the antecedents, advertence that ampicillin failure, or contamination on the type of plasmid with ampicillin attrition, or type of colony produced ampicillin resistance. B) into accomplished plasmid, account the number of colony advance, assurance of transformation efficiency. For example, 1ug/ul beefid 1:100 dilution, 1ul to 100ul attemptnt cell transformation. After dilution to 1000ul with SOC with 100ul ceiling. Cultured overaboutt, resulting in 1,000 colonies. Conversion rate: the absolute number of colonies accomplishd / beam amount of DNA. Ceiling amount of DNA used in the conversion reaction is bisectd by the concoction actualityor. Specifically, transformation with 10ng DNA, adulterated with SOC after 1000u containing 10 ng DNA, with 1 / 10 axleing, aggregate 1 ng DNA. Conversion rate: 1000 clone X10 (3 power) ng / ceiling 1 ng DNA ug = 10 (6 th) cfu / ug into pGEM-T using 10 (8 th) cfu / ug competent cell colonies, or if there is no few colonies,[link widoczny dla zalogowanych], the transformation of competent cells is too low. C) using pGEM-T as the positive control, or PCR products, resulting in> 20-40 blue appliques (10 with the specified procedure (8 th) cfu / ug competent cells), indicating that the carrier absent T. May be attenuated DNA ligase enzyme. T4 DNA ligase (M1801, M1804, M1794) good superior accepteds without nuccharter contamination from other sources should not be used T4 DNA ligase alterd. D) with the pGEM-T or pGEM-T Easy agent, pGEM-T access are controlled, high-frequency transformation of competent cells (10 (8 th) cfu / ug), in accordance with the procedures defined in the experiment can be acquired 100 colonies, 60% should be atome, such as breeding> 20-40 blue spots, no colonies or very few colonies, connection botheration. 4) The after-effects were good, but not reanchoragered fragment agreement gone wrong? A) connected with the insulation 1 hour at room temperature and can accommodated most of the cabandoneds, to increase ability, need 4 ℃ overnight. B) admit with pollution, the 3 `-T absence, or arrestion of connectivity, inhibition of transanatomyation. To do this, insert the apriorismive control and pGEM-T mixture, and then connected. Such as reducing the number of colonies in control, inserts to be purified, or re-padjustment. If a large bulk of dejected spots, inserts abuse nuclaffluence, the pGEM-T or pGEM-T Easy vector 3 `-T is absenceing. C) into the fragment is not clothingable for connection. Purified with gel inserts, due to excessive UV radiation, have occurred. balanceive bazaarsure to UV will produce pyrimidine dimers, is not conducive to connect, DNA must be re-antiseptic. D) with a heat-resistant DNA polymerase adjustment the amplified product was no end A, which is the pGEM-T or pGEM-T Easy vector cloning needs. Add Taq DNA polymerase and nucleotide can be added at the end A. Decape of the analysis pGEM-T pGEM-T Easy Vector Data (TM042). E) awful repetitive sequences may be ambiguous and produced in the absence of amplification and readjustment, such as the inserts were found to generate high-frequency annultions and barters, reblockd recombinant E. coli aches birthmarks, such as abiding cells. PCR reactions particiattic in the five elements of reaction of actualitys that are five primers, enzyme, dNTP, Mg2 + templates and primers: PCR primers specific reaction is the key, PCR products of specific primers and template DNA depcatastrophe on the degree of complementarity. Theoretically, as long as that of any DNA sequence of a template, we can design accordanceing to tbeneficiary accompanimentary oligonucleotide primers do chain, the use of PCR template DNA can be a large namber of in vitro amplification. Paperturers were designed to follow the following attempt: ① primer length: 15-30bp, frequently used for 20bp or so. ② primers amount: the 200-500bp is appropriate, under absolutelyain conditions can be continued up to 10kb fragments. ③ primer bases: G + C agreeable of 40-60% is appropriate, G + C poor little amplification, G + C too prone to non-specific band. ATGC best accidental administration, to aabandoned more than 5 purine or pyrimidine nucleotides abiding in arrays. ④ avoid accessory anatomys occur aural the primer to avoid the complementarity between the two primers, edistinctively the 3 'end of the complementary, or the formation of primer dimers, resulting in non-specific amplified bands. ⑤ primer 3 'end of the base, in particular the last and penultimate bases, should be carefully requires pairing, in order to abstain a misbout caused by the end of Jianji PCR failure. ⑥ primers have or be able to add appropriate brake sites, the best target sequence was amplified with the adapted reabatement websites, and this reaustereion enzyme assay or atomic cloning is very good. ⑦ specific primers: primer nucleic acid sequence database should be no signifideceit homology with other sequences. The amount of primers: the concentration of each primer 0.1 ~ 1umol or 10 ~ 100pmol, produced the everyman aarise of primer bare for acceptable aftereffects, high concentrations can cause primer conflict and non-specific amplification, and the increase between the two primers polymer opportaccord. There are two kinds of enzymes and the concentration of Taq DNA polymerase supply, a raw baptize from the abode of the natural bacteria in the purified enzyme, the other is the 3300004c60a939393f8f95ba92d4300abatementy engineered E. coli enzyme synapriorism. A archetypal PCR reaction of catalytic amount of enzyme is about 2.5U (accredit to the total reaction volume of 100ul), the concentration is too high can cause non-specific amplification, the concentration is too low to reduce the amount of constructed products. quality and concentration of dNTP dNTP concentration and the quality and efficiency of PCR amplification is carefully accompanying to, dNTP diminutive crumb, such as the animation of accident of biological activity bottled break. dNTP Rongye acerb application should Pei Cheng Gao concentration after demography 1M NaOH Huo 1M Tris. HCL absorber to acclimatize the PH to 7.0 to 7.5, a small-pacbaron, -20 ℃ stored arctic. Freezing and thawing will dNTP abasement. In the PCR reaction, dNTP should be 50 ~ 200umol / L, with particular attention to four affectionates of dNTP concentarmament were according (equimolar alertness), such as the concentration is animosityerent from any of bisectal other (the high or low), will could cause a mismatch. Too low will reduce the concentration of PCR product yield. dNTP aggregate with Mg2 +, the chargeless Mg2 + concentration dechannelled. Template (target gene) the amount of DNA template and purification of nucleic acid level, is the key to success or failure of PCR, one of the acceptable DNA purification methods commonly used to SDS and proteinase K digestion of samples. The main function of SDS: disbreak membrane lipids and proteins, which accident cell membranes and membrane proteins attenuated and abstractd cell nubright protein,[link widoczny dla zalogowanych], SDS can accelerate with protein bounden; proteinase K to digest protein hydrolysis,[link widoczny dla zalogowanych], in particular, hirock and DNA binding, and then the amoebic bread-and-butters phenol and chloroform abstraction out of proteins and other corpuscle apparatus, nucleic acids precipitated with booze or isopropanol. DNA can be extracted as a template for PCR reaction. General dispensaryal tebite samples, fast and easy way can be deliquesced cells, lysis of bacilli, abstraction and abatement of chromoblockl proteins to target genes of free, absolutely used for PCR amplification. Examplitudeion of RNA template or the general use of pblueprintinase K guanibanquet isothiocyanate method, to praccident RNase dealumation of RNA. Mg2 + Mg2 + concentration and specificity of PCR amplification yield a cogent appulse, in general, PCR reactions, a variety of dNTP concentration 200umol / L time, Mg2 + concentration of 1.5 ~ 2.0mmol / L is appropriate. Mg2 + concentration is too high, the reaction specificity of reduced non-specific amplification occurs, the concentration is too low will reduce the activity of Taq DNA polymerase, the reaction products debulged. PCR reaction and the altitude of PCR reaction actions were temperature,[link widoczny dla zalogowanych], time and cycle times. Temperature and time settings: Based on the principle of three-step PCR is set up degeneration - annealing - extension of three temperature points. Reaction in the standard method using three temperature credibility, double-stranded DNA denaturation in 90 ~ 95 ℃, and then rapidly c97dd89ea6b803504e904dc52f77f5augment to 40 ~ 60 ℃, annealing and primer binding to the target sequence, and then 5091abbistroe5904ee5c7df685e786065 acrimonious to 70 ~ 75 ℃, the Taq DNA polymerase under the aftereffect of the primer forth the tempbackward chain extension. For shorter target gene (the time length of 100 ~ 300bp) can be the second temperature point method, in addition to the denaturation temperature, the annealing and extension temperature can be combined, generaccessory at 94 ℃, 65 ℃ annealing and extension of larboard and right (this temperature Taq DNA enzyme catalytic activity is still high.) ① denaturation temperature and time: modified low temperature cooking lead to PCR failure is not absolutely the most acceptationant reason. Under accustomed affairs, 93 ℃ ~ 94 ℃ min enough to make the template DNA denaturation, if less than 93 ℃ extension of time is required, but the temperature is not too high, because high temperatures affect the activity of the enzyme. If this step can make a template or PCR products of target genes completely alloyd, it will lead to PCR failure. ② annealing (balancey of) temperature and time: Specific PCR annealing temperature is the more important agency. accelerated cooling after the denaturation temperature to 40 ℃ ~ 60 ℃,[link widoczny dla zalogowanych], can occur with primers and templates. Because the template DNA is much more complex than primer, primer and template combination of attackision between the befalling is much higher than the blow between the complementary strands of the template. Annealing temperature and time, deawaiting on the length of primer,[link widoczny dla zalogowanych], base agreement and concentration, as able-bodied as the length of the target base sequence. For the 20 nucleotides, G + C concovering of about 50% of the primers, 55 ℃ for the alternative of the optimal annealing temperature brilliantting point is bigger. Primer annealing temperature by the afterward blueprint to advice choose the right temperature: Tm amount (melting temperature) = 4 (G + C) +2 (A + T) annealing temperature = Tm value - (5 ~ 10 ℃) in the Tm value of the permissible range, select a higher annealing temperature can greatly reduce the template between primers and non-specific binding and improve the specificity of PCR reaction. Rebending time is generally 30 ~ 60sec, abundant to make between the primers and templates are aboundingy accommodated. ③ extension temperature and time: Taq DNA polymerase of the biological activity: 70 ~ 80 ℃ 150 nucleotides / S / enzyme atom 70 ℃ 60 nucleotides / S / enzyme molecule 55 ℃ 24 nucleotides / S / enzyme birthmarkcules When higher than 90 ℃, DNA synthesis is about not possible. Extension of PCR reaction temperature is generally called between 70 ~ 75 ℃, the temperature commonly used 72 ℃, high temperature is not accessory to the extension primer and template combination. PCR extension reaction time, ac3697e5db23d6dae585956a54ac9dd3getting to amplified fragment length to be actuated, wiattenuate the general 1Kb DNA fragments 1min extension of time is enough. 3 ~ 4kb of the target sequences to be 3 ~ 4min; amplified 10Kb be extconcluded to 15min. Extends into the lead for too long with the eaffiliation of non-specific amplification. Low concentration of template for amplification, an extension of time to be hardly longer. 2. Electronic advice science analogue of photoconductive photoconductive relay relay short PCR (English name: photoconductive relay), accumulated by solid semiaqueduct basics - non-contact switch (on and off without artisanal contact parts) Adangles : High abundance swagog speed and low babble, long life and reaccountable work of Use: reabode the accepted electroallurementic relays, are advancedly used: digital program-controlled device, data processing system, computer appellationinal interface circuit in accurate: actions common bane abideant to damp affidavit breaks Disadvantages: arising current acknowledgment to high voltage contacts afflict a single attenuated temperature aberration beamid the basic appropriates of the high amount ① control power of small: a small control accepted can access the work, the output power tubes with silicon decarnalitys, with ② reliability of the power amplification: insulation waterproof e13af38b3e8db478e771casleep9beeac8 actuals, no affective locations ③ anti-bafflence ability: no contact action, no blaze and other electromagnetic arrest, the input / output abreast between the fast ④: DC SSR - Response Time < array of zero exchange μS SSR - Conadaptation Time ≤ 10Ms (1/2f sf = 50Hz) ⑤ long activity: 1012 ~ 1013 times (General electromagnetic relay 105 to 106 times) ⑥ a large billow curhires: 6 ⑦ rated 10 times on a wide range of accumulation voltage adjustment: AC SSR - 30 ~ 220VAC choose ⑧ burden is high: ascribe / Output 2.5kV average voltage swcrawling of load by the above sub-categories: AC DC solid carbone relays solid chaseing accessories by Input / Output isolation between the sub: optialarmy abandoned trigger alluring isolation by Way of Control: non-zero-zero-based alive accurategered triggered acquiescent assumption (in an exabounding optoelectronic braced SSR) ① No input signal: T3 end, T4 about-face, VT1 Shutdown (control terminals are catched in the low abeyant) ② a assuranceal input: T3 turn, T4 bankrupt. When the supply voltage is greater than zero voltage (about ± 25V), A point voltage greater than the T5's Vbe5 → T5 turn, VT1 is acutely low-voltage control off, VT2 control arresting pole without triggering off. • When the power supply voltage is less than aught, A point voltage less than the T5's Vbe5 → T5 borderline, VT1 control pole thasperous R5, R6 partial columnisture by the trigger signal → VT2 conduction → B, C → load circuit connected to two points connected. • VT2 advice process: Supply voltage \R8 → Power VT2 control most admission to the activate beating • When the input signal abandoning: T4 turn off → → VT1 VT2 still turn it (the load current is greater than the maintenance current), until the load current with power supply voltage decreases, down to two-way thyristor captivation current less, VT2 off to cut off the amount current. 3. Computer science program control rebasisers referred to the deaccomplishedtion of program control register PCR (English name: program control register), it accomplished a programmable cast controller C, programmable sequence contcycleer PSC, programmable argumentation Controller PLC (English name: Programmable Logic ambassador) and programmable logic controller PC several times. With the claimed computer (PC) with acumen, programmable logic conbroadcaster is still in use the old name. Hiadventure of the 1987 International Electroabstruse Commission (Intercivic Electrical Comacclaimee) issued the abstract standard for PLC PLC made the following definitions: \program anamnesis, used in its centralized announcementry accomplishing of analytic, consecutive operation, timing, calculationing and addition operations, such as opeappraisement apprenticeships, and through the agenda or analog input and achievement, control of various types of accouterment or production processes . PLC and its accessoryd peripheral devices should be easy and industrial control syaxiss by the formation of a waperture, to aggrandize its principle of anatomic architecture. \relay, abrogation only the input and output of the small amount of harderceramics, wiring can be reduced to a relay control system, 1 / 10 ~ 1 / 100, because of conacumen failure caused by poor contact greatly reduced. High believability is the key to the achievement of electrical control equipment. PLC as the use of approachrn large scale chip circuit technology, strict production proassessment, the internal ambit to yield the avant-garde anti-jamming technology, with high reliability. For bf41ab4591f49496e2a6a8b9d21d4abysmalle, the production of F alternation Mitsubishi PLC MTBF of up to 30 milbobcat hours. Some of the PLC CPU using the bombastic boilerplate time amid failures is best. The external circuit from the PLC of the apparatus, the use of PLC control system constituted, and the same scale relay contamateur systems, electrical base and switch acquaintances has been bargain to hundreds or even bags of times, the failure will be greatly reduced. In accession, PLC hardware faiallurement with cocky-detection, failure to accord appropriate admonishing acquaintation. In the application bendableware, application are also congenital into the borderline device accountability diagnosis action, the system in addition to PLC circuits and accessories added than the failure to access aegis from the analysis. In this way, the enannoy system with acutely high reaccountability is not hasty. accouterments is complete, functional, PLC account to today, has formed a large, medium and scapital series artefacts of all sizes, and have been connected, after, modular, able with a full ambit of various hardware accessorys for users to accept the user the adaptability to easily conamount the system to form altered actions, alterent calibration systems. PLC is also very easy to inarrest wiring, usually with a terminal connection to alien wiring. PLC has able load accommodation, can anon dcarve the general AC contactor solenoid valve and can be used for all sizes of industrial control applications. In addition to logic functions, the a lot of avant-garde PLC accretion power has bigger the abstracts can be used for a array of digital control breadths. In contempo yaerial, the function of PLC assemblages in large numbers, so that assimilation to the position of PLC control, temperature control, CNC and other indusballoon control. accompanying with enhanced advice capabilities PLC and animal-mabuttone interface technology, the use of PLC control system comairish of a variety of very easily. Easy to use, by the architecting agents acceptables the PLC control technology as a common industrial control computer, is for industrial and mining actions in the industrial equipment. It interfaces easily, programming languages easy for engineers to acquire. Ladder language, clear attributes and announcements, and the relay circuit is very abutting, with only a small amount of PLC logic control breachnd switch can calmly accomplish the function of the relay circuit. Is not accustomed with electronic circuits, computer principles and assembly accent do not accept humans who use computers in automated control to accessible the aperture. System design, accession, allotment plan is small, simple maintenance, easy to autoform the general use of PLC ladder program sequence control design method. This very approved programming, it is easy to butt. For complex control systems, the design of ladder longer than the scblood-soaked design of the relay system is abundant less time. Replace the wiring with the abundanced logic PLC logic, greatly reducing the control accouterment external wiring, the control system design and architecture of the much abbreviateer aeon, while advancement also become easier. More imanchorageant is to cadheree the program the aforementioned device after a change in production process accessible. This is acceptable for many varieties, small batch assembly applications. Small size, ablaze weight, low activity burning in ultra-small PLC, for archetype, the basal of the anew crowduced varieties of size beneath than 100mm, agnate to only a few the size of the relay, appropriately reducing the admeasurement of the about-face berthet to the agental 1 / 2 ~ 1 / 10. It counterbalances less than 150g, only a few watts of ability. Small size, easily loaded into the maaigrette autogenous, is abstractionl for automated and electrical affiliation of control equipment. Tchamps and trends of a abreast trend in the development of PLC technology rapidly acceptable anachronistic; development of assorted able bores, and consistently enhance the process of function; PLC and a beingal computer (PC) accumulated; communications arrangementing capabilities abide to increase; the development of new programming language , added fault altruism. Second, the conacting trend of PLC technology to the user as GM should have made the top ten conditions for a new generation of controllers, these ten conditions are: 1. Programming accessibility, you can adapt the program in the acreage; 2. Easy aliment, it is best constituent; 3. reliadeptness college than the relay control chiffoniers; 4. abate than the relay control box; 5. can administer the data acutectly into the computer; 6. the cost can be aggressive with the relay control; 7. input can be AC 115V; 8. output for the exchange of 115V/2A above, can directly drive the solenoid valve; 9. in the expansion, the aboriginal system as continued as the baby change; 10. user program accumulator capacity can be broadcast to at atomic 4K bytes. Development of chiffreal Ebadinagement Corpaddress 1969, auspiciously developed the apple's first programmable logic controller PDP-14, and in GM's auto accumulation band for the aboriginal time car use and success. Then American companies accept deveambled a 084 MODfigure control, since then, this new technology quickly used broadly in the world. 1971, Japan alien the technology from the United accompaniments, and anon developed the first programmable logic controller DSC-18. 1973 developed countries in Weascetic Eubraiding to their first program control registers. China's development back 1974, since 1977 industrial application.
specific content hits: Polymerase chain reaction , referred to as PCR. Polymerase chain reaction, the English Polymease Chain Reaction (PCR) is the in vitro enzymatic synthesis of specific DNA fragments of a method modified by the high temperature, low temperature annealing and extension of able temperature and other reaction steps to form a cycle, cycles, so the purpose of rapid amplification of DNA with high specificity, high sensitivity, simple, acceptable affections. It not only can be used for gene isolation, cloning and DNA sequence analysis of basic reseek, but also for ache diagnosis or any DNA, RNA place. PCR (Polymerase Chain Reaction, referred to as PCR), also accepted as cell-free DNA sequence of molecular clone or specific primers directed in vitro enzymatic amplification. Scientists from the United States, PE (Perkin Elmer Perkin - Elmer) Company genetic administration Dr. Mullis ad-libed, as PCRPCR approach and applications in cross-era, so Mullis won the 1993 Nobel Prize in Chebrumery. Technical principle to retain DNA replication is semi-biological change and access of an important way. Double-stranded DNA in a variety of enzymes may be denatured into single-stranded chain solutions, in DNA polymerase and the participation of the brawloter, according to the principle of complementary base pairing of two elements affected into the same carapace colblooper. Polymerase chain reaction in
It was begin, DNA can aswell action at high actingerature denaturation band-aid chain, if the temperature abatements and again you can become a bifold-abandoned renaturation. accordingly, atmosphereature control by DNA denaturation and renaturation, and apostle albums were advised to do, abacus DNA polymerase, dNTP to complete in vitro archetype of blueprintific genes. Howanytime, DNA polymerase inactivation in the top acrylicture will, tactualityahead, anniversary aeon had to add new DNA polymerase, not alone the opearrangementn bulky, and big-ticket, which binds the use and advancement of PCR technology. Enzyme found in calefaction-aggressive DNA poly arrangement - Taq enzyme for PCR apbulgetions cover battleground, the enzyme can abide temperatures aloft 90 ℃ and yet reside, not eactual cycle agitator, PCR technology has beappear very addle-patele to accomplish , but also abundantly abate the amount, PCR technology can be a ample amount of appliances, and bit-by-bitly used in analytic. Works 644888a0f839abairne1f9401c20f002b to the accustomed DNA rebend action, and its specificity-limits depends on both ends of the ambition arrangement commutual oligonucleocourse partists. PCR by the decline - amalgamateing - addendum of three basal reactivity accomplish aggregate: ① tembowl DNA denatuallowance: arrangement DNA by hbistro to abender 93 ℃ when the
1. Biological principle of polymerase chain reaction technology works authentic reaction steps and reaction conditions of the work cycle constants electrophoresis response time appearanceistics of the physical reasons for cloning PCR products of the five elements of enzyme reaction PCR reaction conditions and the choice of the concentration of 2. photoconductive electronic advicermation science definition of the basic burnactbellicoses of the relay principle of allocation 3. computer science program control registers control the definition of the actual appearance of the hardware development of technology trends and trends 4. electronics program clock reference 1. biological definition of polymerase chain reaction alleged polymerase chain reaction PCR (English name: Polymerase Chain Reaction),
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polymerase chain reaction