Genetic switch regulates transcription and replication in human mitochondria

first_img Mitochondrial DNA, unlike nuclear DNA, undergoes transcription and replication at the same location. The transcriptional proteins used to read the mitochondrial RNA (mtRNA) strand, made from the mtDNA, are different from the ones used in replication but occur at the same time and space, which could potentially result in a collision and subsequent problems in gene expression. Temiakov’s group investigated whether TEFM, a mitochondrial transcription elongation factor that has been shown to escalate transcription activity in promoterless DNA, plays a role in regulating transcription and replication in the mitochondria.Transcription in the mitochondria occurs at two locations, the light strand promoter and the heavy strand promoter. Prior studies have shown that transcription terminates early, about 120 base pairs before the light strand promoter, at a region of mtDNA found in most vertebrates, known as CSBII, or conserved sequence block II. A hybrid complex forms with the nascent RNA and the nontemplate strand of DNA.This complex forms near the origin of the of the replication primer for the heavy strand, and will replicate two-thirds of the mtDNA on the heavy strand. It stops near the origin of the light strand. The now single light strand forms a hairpin structure that is recognized by the mitochondrial RNA polymerase as the signal to begin replication of the light strand.Temiakov’s group showed that in the presence of TEFM, the mitochondrial DNA polymerase does not stop at CSBII as it typically does in human mtDNA transcription, but continues transcribing through the CSBII section. Because TEFM prevents transcription termination, it also prevents the synthesis of the mtDNA polymerase primer that is used in replication. This finding provided one of several clues that TEFM acted to regulate replication and transcription in human mitochondrial DNA.While conducting this study, the group inadvertently found that because their reference genome has a rare polymorphism in the CSBII region, they observed a decrease in efficiency of the transcription termination mechanism. They believe that the polymorphism disrupted the formation of the G-quadruplex, and that this G-quadruplex is involved in the CSBII mechanism.Further investigations of how the G-quadruplex is involved in the TEFM mechanism showed that the TEFM interacts with the particular portions of the nascent RNA transcript. Temiakov’s group believes that the TEFM interferes with the formation of the G-quadruplex, causing the hairpin structure to not form. This, in turn, does not signal to the mtRNA polymerase to begin replication.Further studies showed that TEFM affects how well mtRNA polymerase is able to produce long transcripts. Without TEFM, shorter transcripts are formed, terminating at the CSBII region. TEFM increases processivity of mtRNA polymerase.Temiakov concludes that TEFM serves as a switch that either “turns on” transcription, making it more efficient, or it “turns on” replication. This research indicates that replication and transcription are likely mutually exclusive processes in the human mitochondrial genome precluding the possibility that the transcription and replication processes will collide. Furthermore, this switch may be a key player in the developmental processes in which transcription of mtDNA occurs but not replication. Explore further © 2015 Phys.org More information: “Replication-transcription switch in human mitochondria” Karen Agaronyan, Yaroslav I. Morozov, Michael Anikin, Dmitry Temiakov, Science, vol 347, issue 6221, January 30, 2015, DOI: 10.1126/science.aaa0986ABSTRACTCoordinated replication and expression of the mitochondrial genome is critical for metabolically active cells during various stages of development. However, it is not known whether replication and transcription can occur simultaneously without interfering with each other and whether mitochondrial DNA copy number can be regulated by the transcription machinery. We found that interaction of human transcription elongation factor TEFM with mitochondrial RNA polymerase and nascent transcript prevents the generation of replication primers and increases transcription processivity and thereby serves as a molecular switch between replication and transcription, which appear to be mutually exclusive processes in mitochondria. TEFM may allow mitochondria to increase transcription rates and, as a consequence, respiration and adenosine triphosphate production without the need to replicate mitochondrial DNA, as has been observed during spermatogenesis and the early stages of embryogenesis. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. DksA polices the intersection of replication and transcriptioncenter_img Journal information: Science (Phys.org)—The majority of the human genome is located within the nucleus. However, there is a small but important portion of DNA located within the mitochondria. This mitochondrial DNA (mtDNA) has received much attention in the last few years for tracing ancestry, mitochondrial disease, and three-parent IVF. Mitochondrial DNA’s unique properties mean that it has different regulatory mechanisms. A new study by Dmitry Temiakov from Rowan University reports for the first time evidence that mtDNA transcription and replication are regulated by a molecular switch that may provide insight into developmental processes such as embryogenesis and spermatogenesis. The results are reported in Science. Citation: Genetic switch regulates transcription and replication in human mitochondria (2015, February 2) retrieved 18 August 2019 from https://phys.org/news/2015-02-genetic-transcription-replication-human-mitochondria.html Mitochondria. Credit: Wikipedia commonslast_img read more

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New nanotweezers able to move submicrometer size objects in fluids

first_img Explore further PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen As the researchers note, one of the important goals in nanotechnology research is to create tools to manipulate extremely tiny objects, particularly those that exist in fluid. In this new effort, the researchers describe a unique new type of mobile nanotweezers (MNT) that is able to capture and release extremely tiny particles with unprecedented speed and spatial resolution, possibly opening the door to the development of applications such as lab-on-a-chip technology.The MNT combines features of plasmonic tweezers and microbots, and is shaped like a common screw—each is magnetic and has silver particles embedded on the outside of its body that cluster when exposed to light due to plasmonic properties. Each is a ferromagnetic nanostructure grown using electron beam evaporation of silicon dioxide. Control of the MNT is done using a directed magnetic field. When in action, the MNT spirals through a fluid until it reaches a target. Light is then applied to cause the silver particles to constrict, using their trapping force to hold onto a target. The MNT is then moved to a destination, whereupon the light source is turned off, relaxing the silver particles causing the MNT to release its target. Play Directed by a rotating magnetic field, the mobile nanotweezers spin through their environment and capture their targets without accidentally “trapping” other particles. Credit: Ghosh and Ghosh, Sci. Robot. 3, eaaq0076 (2018) PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen Two researchers with the Indian Institute of Science have developed tiny tweezers that can manipulate objects in fluids as small as an individual bacterium. In their paper published in the journal Science Robotics, Souvik Ghosh and Ambarish Ghosh describe their nanotweezers and how well they work. Citation: New nanotweezers able to move sub-micrometer size objects in fluids (2018, January 12) retrieved 18 August 2019 from https://phys.org/news/2018-01-nanotweezers-sub-micrometer-size-fluids.html Journal information: Science Roboticscenter_img New approach uses light instead of robots to assemble electronic components The mobile nanotweezers are comprised of a screw-shaped magnetic microrobotic body dotted with silver particles that cluster in response to light. Credit: Ghosh and Ghosh, Sci. Robot. 3, eaaq0076 (2018) More information: Souvik Ghosh et al. Mobile nanotweezers for active colloidal manipulation, Science Robotics (2018). DOI: 10.1126/scirobotics.aaq0076AbstractAn important goal in nanotechnology is to control and manipulate submicrometer objects in fluidic environments, for which optical traps based on strongly localized electromagnetic fields around plasmonic nanostructures can provide a promising solution. Conventional plasmonics based trapping occurs at predefined spots on the surface of a nanopatterned substrate and is severely speed-limited by the diffusion of colloidal objects into the trapping volume. As we demonstrate, these limitations can be overcome by integrating plasmonic nanostructures with magnetically driven helical microrobots and maneuvering the resultant mobile nanotweezers (MNTs) under optical illumination. These nanotweezers can be remotely maneuvered within the bulk fluid and temporarily stamped onto the microfluidic chamber surface. The working range of these MNTs matches that of state-of-the-art plasmonic tweezers and allows selective pickup, transport, release, and positioning of submicrometer objects with great speed and accuracy. The MNTs can be used in standard microfluidic chambers to manipulate one or many nano-objects in three dimensions and are applicable to a variety of materials, including bacteria and fluorescent nanodiamonds. MNTs may allow previously unknown capabilities in optical nanomanipulation by combining the strengths of two recent advances in nanotechnology. Play Capture and release of different-sized silica beads by a mobile nanotweezer nanorobot. Credit: Ghosh and Ghosh, Sci. Robot. 3, eaaq0076 (2018) The researchers demonstrated the abilities of their MNTs by moving around tiny diamonds, silica beads and samples of the Staphylococcus aureus bacteria. They note that testing also showed that the MNTs were able to grab objects without accidentally grabbing other nearby objects. They suggest their MNTs could be used in nano-assembly applications. The researchers are continuing their work with the MNTs, looking to find ways to allow them to work in parallel (using multiple overlapping magnetic fields), which could broaden their usability in commercial applications by allowing hordes of them to work together to accomplish an overall task. © 2018 Phys.org This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

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Artistes to teach not perform

first_imgIndia Habitat Centre in collaboration with SIET and SAKSHI is organising Sound Of Music – a workshop. It will be an introduction to musical instruments of India. Recognition, cognition and appreciation of instrumental music with eminent and world acclaimed musicians is a rare chance that one gets. The program aims to create awareness and to bring back the charisma of Indian classical music among the educated, urban middle class youth, who know very little about the depths and intricacies of Indian Classical Music or the instruments used therein. The artistes too need a broader visibility and deserve to be acclaimed by the many that have not had an easy opportunity to enjoy such arts. Also Read – ‘Playing Jojo was emotionally exhausting’One can learn about wind instruments like flute, shehnai, nagaswaram, clarionet, saxophone, plucked string instruments like sitar, santoor, sarangi, sarod; bowed instruments like violin, dilruba, esraj, cello;  and percussion instruments such as drums, tabla, manjira and many more. What more, one gets to learn from eminent people like Sudeep Rai, Shakeel Ahmed, Pt. Ajay Prasanna, Ghulam Ali,  Ustad Rafiuddin Sabri, Anees Ahmed, Ustad Aleem Khan, Chandrima Majumdar and Abhay Rustum Sopori. Quite a number of names, aren’t they? Well, they aren’t just names but people who excel in their fields.  Also Read – Leslie doing new comedy special with NetflixRai is one of the leading instrumentalist of India a disciple of sitar maestro Padmabhushan Pt. Debu Chaudhuri, He has been acknowledged by connoisseurs as a worthy successor to his Guru’s tradition. Rai’s style resonates with maturity that is far beyond his years. In an era where fusion and new age music dominate the current Indian music scenario, Ahmed, is a rare performer who continues to excel and please the connoisseur with his impeccably rendered  traditional puritan raga based gayaki. Born and brought up in a traditional musical, gharana family of Delhi, Ahmed was immersed in the musical arts from his birth and is the beneficiary of gurus who hail from the Delhi gharana and are the repository of centuries of grooming, training and research in the journey of Hindustani classical music whose origin is believed to be from the Samvedas. Ajay Prasanna hails from a family of classical musicians. He received his training in flute from his father- Guru Pt. Bholanath Prasanna from the Banaras Gharana, who is also the Guru of Pt. Hari Prasad Chaurasia. Prasanna started his training in Indian classical music at a tender age of 3 years, by simply observing his father play the flute and teach his students. A rare combination of innovator and traditionalist, Prasanna is currently a top grade classical artiste at the All India Radio, the national broadcaster. Sonipat Agra Gharana (Sarangi) Ghulam Ali is the doyan and torchbear of Agra Sonipat Gharana which has perfected Sarangi playing.Ghulam Ali is the son of the celebrated Musician Ustad Tajuddin Khan Sahab. He learnt to play the Sarangi from Ustad Wazir Hussain Khan of Sonipat-Agra Gharana, where he also learnt the gayaki of Agra gharana. We can go on telling you about these artistes, but we cannot teach you what they’d do when you go and meet them!When and Where: 23 June to 26 June 2014 at Amaltas Auditorium,30 June 2014 at Stein Auditorium in the Indian Habitat Centre from 6.30 pm – 8.30 pmlast_img read more

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College admission and fees to go online from next year Mamata

first_imgKolkata: Amidst regular complaints of extortion from students for admission to colleges, Chief Minister Mamata Banerjee on Tuesday said that fees for the purpose will have to be paid online through banks from next year.She made it clear that undergraduate admission in colleges across the state would be strictly on the basis of merit and there would be no counselling from 2019.”Admission related fees would be collected through banks,” Banerjee told reporters while leaving the state Secretariat. The state Higher Education department has already issued a notification in this regard making it clear that students will no longer have to travel physically to the institutions for purpose of admission. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedState Education minister Partha Chatterjee further reiterated that admission in colleges can be carried out without verification and counselling.”The verification would be conducted after the first year admission procedures are complete. We have sent the instruction to all colleges in the districts regarding the cancellation of counselling. We have sought information on the availability of seats in various institutes. For verification, no admission procedure would be stopped,” he maintained making it clear that the new process will ensure that student unions will not be able to have any effect on college admissions. Also Read – Naihati: 10 councillors return to TMC from BJPMeanwhile, the Kolkata Police continued its crackdown against those involved in collecting money for admission and the sleuths of the anti-rowdy section of the detective department on Tuesday afternoon arrested one S K Jasimuddin (20), a second-year student of Surendranath College while taking money to the tune of Rs 30,000 from a student for admission in Zoology Honours course. It is learnt that Jasimuddin had told Shreyasi Patra, the student, that against the payment he would make arrangements for her admission in one of three colleges of her choice — Bangabasi or Surendranath College or City College. Shreyasi, a resident of Panchla in Howrah, had come to Jagat cinema hall in Sealdah as directed by Jasimuddin and was caught red-handed. The Trinamool Chattra Parishad (TMCP) took a strong stand against irregularities of admission and dismantled the unions in four colleges — Gurudas College, Vidyasagar College, City College and Ananda Mohan College.TMCP president Jaya Dutta who held a meeting with student representatives of North Kolkata colleges on Tuesday announced the decision of the TMCP and said the party will not stand by anybody who will be found indulging in extortion for admission and the police will take stern action as per law.Meanwhile, principals of the morning, day and night sections of Surendranath College came together to talk on the ongoing issues in the college. The police had raided the residence of a Group D staff of the college — Ratul Ghosh — for his involvement in admission irregularities on Monday but were unable to trace him.Indranil Kar, principal of Surendranath Day College, said: “We have not found any proof against him. In absence of concrete evidence, no action can be taken against him by the governing body of the college. However, as the administrator of the institute, I have issued a letter at his registered address asking for the truth of the matter. We have also sought his reply within seven days.”On the question of Ratul being absconding and taking a probable hide at Bankura, the principal said that he has been absent since later part of last week. “Since the college has just resumed classes after the summer recess, confirming him being absconding or taking a hide is difficult,” he claimed.The pro vice-chancellor of Panchanan Verma University in Cooch Behar Deb Kumar Mukhopadhyay paid visits to various undergraduate colleges in the district to ensure that there is no irregularity in the admission process. He also spoke to students and their guardians to instill confidence among them.last_img read more

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Elderly man shot dead over carrom rent dispute

first_imgKolkata: An elderly person was shot dead in a dispute over renting a carrom board at Kamarhati in North 24-Parganas on Wednesday night.Two persons have been arrested by the police in this connection.According to the police sources, it was around 11 pm, when locals heard sounds of firing in the Tutbagan area.They came out only to find Jainul Haque lying on the road with blood oozing out from the wound on his neck. The sexagenarian was rushed to Sagar Dutta Medical College Hospital where he was declared brought dead. Locals said Jainul had a carrom board that he used to offer on rent. Every evening some or the other local youth would come and play. However, nobody turned up in the evening until around 10 pm. Also Read – Rain batters Kolkata, cripples normal lifeOn Wednesday, around 10 pm, four persons came and played carrom in front of the elderly man’s residence.On finishing the game, Zainul demanded the rent for the board, which he was refused.When Zainul insisted they should pay up, a heated exchange of words ensued and all of a sudden, one of the youths took out a firearm, and fired at him. One of the bullet hit his neck and he immediately fell down on the road. All four fled the spot in the two motorcycles they had brought along with them.The police fixed up two youth on the basis of CCTV footages available and arrested Akhtar Ali and Chotu for being involved in the crime. The sleuths said the duo has confessed they had fired. “We are grilling the two to trace the whereabouts of the other two who are still at large,” a senior police officer.last_img read more

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Minor fire at Kasba housing apartment

first_imgKolkata: A small fire broke out on Wednesday night following an explosion inside a room of a security guard at a housing apartment in south Kolkatas Kasba area, police said. There was no report of any injury, they said. The fire was reported at around 9.15 pm following the explosion that blew away the windows and doors of the security guards room in Bosepukurs Talbagan area, a police officer said. The security guard was not present at the time of the explosion, he said. “The cause of the explosion and fire is not known,” the police officer said.last_img read more

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State BJP leader to get X category security cover

first_imgKolkata: The Union Home Ministry has decided to provide ‘X’ category security to state BJP leader Joy Banerjee. It has been decided that Banerjee will be given ‘X’ category security under which 3 Central security personnel will be deputed. One more personnel will be kept on reserve. According to sources, four BJP leaders in the state get special security from Union Home Ministry at present. Among them Rahul Sinha was the first to get CRPF personnel as security. Later, BJP state president Dilip Ghosh was provided with ‘Y’ category security. After Mukul Roy joined BJP, he was provided with ‘Y Plus’ category security. Rupa Ganguly also gets ‘X’ category security.last_img read more

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Thanks to NKDA city to get its first staterun dog crèche

first_imgKolkata: New Town Kolkata Development Authority (NKDA) will open the first state-run crèche cum clinic and cemetery for pet dogs at Action Area III in New Town on February 1. There will be a dog show at the inaugural function.The clinic will remain open from 11 am to 2 pm from Monday to Saturday. The service provided by NKDA assumes significance as the need for the same has grown all over the city, including New Town and Salt Lake, over the years. There are large breeds like Great Dane, French Mastiff, English Mastiff, Afghan Hound, St. Bernard and Tibetan Mastiff, in addition to Labradors, Golden Retrievers and German Shepherd Dogs in Kolkata and its adjoining areas. Dog shows are attracting more and more people nowadays as well. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThe fees for visiting the Out Patient Department (OPD) of the clinic will be Rs 150. For keeping pet dogs at the crèche, charges will be Rs 750 per day for large breeds and Rs 500 per day for small breeds. The owners will have to pay Rs 10,000 as security deposit. All the deposits will have to be paid in advance and the owner will have to deposit a certificate from a doctor stating that the dog does not carry any infectious disease. Copies of the documents of last vaccination and details of the regular medicines will have to be submitted as well. Also Read – Bose & Gandhi: More similar than apart, says Sugata BoseThe owners will have to deposit the regular medicines for the period of stay in the crèche. Only medicines during emergency will be supplied by the authority. The cost of such treatment will be deposited from the security deposit. There will be experienced vets, care guides and handlers at the crèche. There will also be a cemetery where 25 pet dogs can be buried. It becomes a major hassle for owners to get a suitable cemetery for their beloved pets. The burial charge will be Rs 2,500 and the owner of the dog will have to submit a death certificate of the canine from a recognised veterinary doctor. Dog lovers all over Kolkata have welcomed the move of NKDA. They said that there should be some good crèches for pet dogs in Kolkata Municipal Corporation (KMC) area as well.last_img read more

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100 villagers taken ill after consuming contaminated food

first_imgKolkata: Nearly 100 people were taken ill after they had food at a religious progarmme at Chapra in Nadia on Monday night. It is suspected they fell sick after eating biryani at the event. The incident triggered panic among the villagers in the district.According to sources, as many as 16 persons are critically ill and they are undergoing treatment at the Shaktinagar Hospital in Krishnanagar. The local MLA Rukbanur Rahman visited the patients at the hospital. The district administration has started a probe into the incident. Also Read – Rs 13,000 crore investment to provide 2 lakh jobs: MamataThey are yet to ascertain the exact cause of the incident. The district officials have already collected samples of the food that was served to the people who joined the event. Most of the patients started vomiting and had complaint of nausea after they consumed the food. It was learnt that the people from Pukhuria village of Chapra attended the programme on Monday night. Most of the victims were taken ill after having the food there. Many of them were immediately rushed to the hospital. Also Read – Lightning kills 8, injures 16 in stateLocal MLA Rukbanur Rahman spoke to the family members of the victims and later interacted with the doctors to ensure that the patients get the best treatment. Rahman also assured the family members of the patients that they would not face any problems in availing proper treatment. The district administration is yet to confirm if the problem triggered from the food or the drinking water at the programme. They are not ruling out the possibility of people consuming contaminated water during the event. The reasons will only be confirmed after the food and water will be examined in the laboratory. The samples of food and drinking water have been sent for examination. A senior official of the health department in the district said it is suspected that the food or the drinking water might have been contaminated. The actual cause of the incident will be determined once the samples are examined in the laboratory, he said.last_img read more

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Beauty regime that needs change with season

first_imgEvery season brings with it a different set of skin characteristics and problems. It can get hard to keep up with the ever changing beauty regime but it is extremely important as the same beauty regime can damage the skin in several ways. Experts list down some tips for your skin to keep up with the changing seasons:C-T-M for all seasons: The routine of cleansing-toning-moisturizing remains the same in all seasons with variations only in product types. Summers call for deep-clean cleansers. Monsoon require shine and glow cleansers whereas winters call for mild cleansers along with intense moisturizing. Toner with green cucumber and tea would be the best for the hotter weather and to keep the acne at bay. Also Read – Add new books to your shelfIt is also very important to make sure the product being used in your beauty regime are organic as it not just helps the skin maintain its hydration but also treats it from within as the ingredients are in the purest form.Season specific SPF: Sunscreen is a must have and remain the same for all seasons, but monsoon particularly requires a water-proof sunscreen.Night time skin care: As skin is the most active at night, it is important to use a nourishing night cream. An organic night cream not only maintain the moisture but also helps delay ageing. Also Read – Over 2 hours screen time daily will make your kids impulsiveScrub it off: An organic Anti-Tan scrub is important for the summers, whereas a regular organic exfoliating scrub is prefect for monsoon and winters, but be careful while scrubbing skin when it’s rough and dry.Must have lip balm: Lip balms’ importance remain constant throughout but a shea butter lip balm would work like magic, especially in winters.Do not switch over directly/entirely to another seasonal regime. Follow the tapering method to switch over Oiling the hair and/or body massages are necessary for health, flexibility, strength and vitality, and should be included in one’s regimes in every season.It is also not wise to change the entire range of product/brands being used suddenly, as this may lead to untoward effectsThe amount and frequency of moisturisation should be adapting to the fluctuating temperatures of the changing seasons. The same applies to cleansing regimes, which may be more frequent during summer.The Summer and Monsoon seasons bring increased potential for infections, thus adequate hygiene has to be maintained internally and externallyToning suits all the needs of all seasons, as it helps purify clogged skin pores and minimises their enlarged appearance for a smoother, younger-looking complexion It is advised that any products or methodologies adopted should not be overusedExcessive use of makeup during transitioning seasons should be avoidedEat well, sleep well, exercise wellAlways wear a smile! It helps take an optimistic approach to every day and focus on the enjoyable aspects of the changing seasonsConsult an expert if any problem persists.last_img read more

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