HIV & SpaceX Troubles | SciByte 84

HIV & SpaceX Troubles | SciByte 84

We take a look at a HIV-infected infant that is \”Functionally Cured,\” a really old star, one big Antarctic meteorite, renaming a NASA center, an update on a private Mars mission and the Dragon space station supply mission, Curiosity news, and as always take a peek back into history and up in the sky this week.

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Show Notes:

\”Functional Cure\” in an HIV-Infected Infant

  • A team of researchers from Johns Hopkins Children\’s Center has described the first case of a so-called \”functional cure\” in an HIV-infected infant
  • The infant described in the report underwent remission of HIV infection after receiving antiretroviral therapy (ART) within 30 hours of birth
  • Natural Viral Suppression
  • Natural viral suppression without treatment is an exceedingly rare phenomenon observed in less than half a percent of HIV-infected adults
  • HIV experts have long sought a way to help all HIV patients achieve elite-controller status
  • \”Elite controllers,\” whose immune systems are able to rein in viral replication and keep the virus at clinically undetectable levels
  • Functionally Cured
  • \”Functionally cured,\” a condition that occurs when a patient achieves and maintains long-term viral remission without lifelong treatment and standard clinical tests fail to detect HIV replication in the blood
  • A functional cure occurs when viral presence is so minimal, it remains undetectable by standard clinical tests, yet discernible by ultrasensitive methods
  • Sterilizing Cure
  • A sterilizing cure-a complete eradication of all viral traces from the body
  • A single case of sterilizing cure has been reported so far in an HIV-positive man treated with a bone marrow transplant for leukemia.
  • The bone marrow cells came from a donor with a rare genetic mutation of the white blood cells that renders some people resistant to HIV
  • Such a complex treatment approach, however, HIV experts agree, is neither feasible nor practical for the 33 million people worldwide infected with HIV
  • Medical Details
  • The child described was born to an HIV-infected mother and received combination antiretroviral treatment beginning 30 hours after birth.
  • A series of tests showed progressively diminishing viral presence in the infant\’s blood, until it reached undetectable levels 29 days after birth
  • The infant remained on antivirals until 18 months of age, at which point the child was lost to follow-up for a while
  • Ten months after discontinuation of treatment, the child underwent repeated standard blood tests, none of which detected HIV presence in the blood
  • Test for HIV-specific antibodies-the standard clinical indicator of HIV infection-also remained negative
  • Antiviral Treatment
  • Investigators say the prompt administration of antiviral treatment likely led to this infant\’s cure by halting the formation of hard-to-treat viral reservoirs
  • Prompt antiviral therapy in newborns that begins within days of exposure may help infants clear the virus and achieve long-term remission without lifelong treatment by preventing such viral hideouts from forming in the first place
  • Dormant cells are responsible for re-igniting the infection in most HIV patients within weeks of stopping therapy
  • Researchers say they believe this is precisely what happened in the child described in the report
  • What This Means
  • Currently, high-risk newborns-those born to mothers with poorly controlled infections or whose mothers\’ HIV status is discovered around the time of delivery-receive a combination of antivirals at prophylactic doses to prevent infection for six weeks and start therapeutic doses if and once infection is diagnosed
  • This particular case may change the current practice because it highlights the curative potential of very early ART
  • Investigators caution they don\’t have enough data to recommend change right now to the current practice of treating high-risk infants
  • This infant\’s case provides the rationale to start proof-of-principle studies in all high-risk newborns
  • The next step is to find out if this is a highly unusual response to very early antiretroviral therapy or something we can actually replicate in other high-risk newborns
  • Researchers say preventing mother-to-child transmission remains the primary goal as they already have proven strategies that can prevent 98 percent of newborn infections by identifying and treating HIV-positive pregnant women
  • Multimedia
  • Image Scanning electromicrograph of an HIV-infected T cell. (Credit: NIAID) | ScienceDaily.com
  • Further Reading / In the News
  • Researchers describe first \’functional HIV cure\’ in an infant | MedicalXpress
  • Synthesized compound flushes out latent HIV | MedicalXpress
  • Researchers Describe First \’Functional HIV Cure\’ in an Infant | ScienceDaily.com

— NEWS BYTE —

A Star That’s Almost as Old as the Universe

  • Results from a new study show that a metal-poor star located merely 190 light-years from the Sun is 14.46+-0.80 billion years old, which implies that the star is nearly as old as the Universe
  • Such metal-poor stars are important to astronomers because they set an independent lower limit for the age of the Universe and can be used to corroborate age estimates inferred by other means
  • Amount of Metal vs Age of Star
  • Metal-poor stars can be used to constrain the age of the Universe because metal-content is typically a proxy for age
  • Heavier metals are generally formed in supernova explosions, which pollute the surrounding interstellar medium.
  • Stars subsequently born from that medium are more enriched with metals than their predecessors with each successive generation becoming increasingly enriched
  • The reliability of the age determined is likewise contingent on accurately determining the sample’s metal content, and is likewise contingent on the availability of a reliable distance
  • Analyses of globular clusters and the Hubble constant yielded vastly different ages, by billions of years, for the Universe, the discrepant ages stemmed partly from uncertainties in the cosmic distance scale
  • HD 140283
  • HD 140283 exhibits less than 1% the iron content of the Sun, which provides an indication of its sizable age.
  • Based on the microwave background and the Hubble constant, it must have formed soon after the big bang
  • This star had been used previously to constrain the age of the Universe, but uncertainties tied to its estimated distance (at that time) made the age determination somewhat imprecise
  • Scientists were recently also to obtain a new and improved distance for HD 140283 using the Hubble Space Telescope (HST), namely via the trigonometric parallax approach
  • From that data the distance uncertainty for HD 140283 was significantly reduced by comparison to existing estimates, thus resulting in a more precise age estimate for the star
  • The age of HD 140283 does not conflict with the age of the Universe, 13.77 ± 0.06 billion years, within the errors
  • This study reaffirms that there are old stars roaming the solar neighborhood which can be used to constrain the age of the Universe
  • Multimedia
  • Image A new age estimate for the star HD 140283 implies that it was among the first few generations of stars created in the Universe | NASA, ESA, A. Felid (STScI) | UniverseToday.com
  • Further Reading / In the News
  • Nearby Ancient Star is Almost as Old as the Universe | UniverseToday.com

— TWO-BYTE NEWS —

Antarctic Meteorite Season Findings

Voting to rename NASA Dryden after Neil Armstrong

— SPACECRAFT UPDATE—

SpaceX – Dragon Space Station Resupply Mission Glitch

  • The Glitch
  • The problem cropped up immediately following Dragon\’s separation from the rocket upper stage, nine minutes into the flight.
  • Three of the four sets of thrusters on the company\’s unmanned Dragon capsule did not immediately kick in, delaying the release of the solar panels.
  • The problem may have been caused by a stuck valve or a line blockage
  • Dragon\’s twin solar wings swung open two hours later than planned, an hour later, the Dragon was raised with the thrusters to a safe altitude.
  • Working Towards the Solution
  • SpaceX worked to bring up the idled thrusters and keep the capsule on track
  • The Dragon is equipped with 18 thrusters, divided into four sets, and can maneuver adequately even with some unavailable.
  • The capsule is designed to return to Earth with just two good sets of thrusters and, in \”a super worst case situation,\” conceivably just one although it would be \”a bit of a wobbly trip.\”
  • If SpaceX and NASA had determined that more time was needed to gain confidence that Dragon could safely carry out an attempt the Dragon could have stayed in orbit for several additional months if needed
  • By late Saturday afternoon sufficient recovery work had been accomplished to warrant NASA, ISS and SpaceX managers to give the go-ahead for the Dragon to rendezvous with the station early Sunday morning, March 3.
  • Capture
  • The capsule was captured 5:31 am EST (1031 GMT) on Sunday, March 3
  • More than 1 ton of space station supplies aboard this Dragon, which included some much-needed equipment for air purifiers
  • It is scheduled to spend more than three weeks at the space station before being cut loose by the crew
  • Despite the one-day docking delay, the Dragon unberthing and parachute assisted return to Earth will still be the same day as originally planned on March 25.
  • History
  • This has been the first serious trouble to strike a Dragon in orbit, none of the four previous unmanned flights had any thruster issues
  • On the previous flight in October, one of nine first-stage engines on the Falcon rocket shut down too soon, on this flight it performed \”really perfectly\” and that the thruster problem was isolated to the Dragon
  • Future Re-Supply Missions
  • SpaceX plans to launch its next Dragon to the station in late fall.
  • SpaceX says it has 50 launches planned-both NASA missions and commercial flights-totaling about $4 billion in contracts
  • NASA also has a $1.9 billion resupply contract for the station with Orbital Sciences Corporation, which will launch the first test flight of its Antares rocket from a base in Virginia in the coming weeks
  • Multimedia
  • YouTube SpaceX Dragon Carrying NASA Cargo Arrives at International Space Station | NASATelevision
  • Further Reading / In the News
  • SpaceX\’s capsule arrives at ISS | phys.org
  • SpaceX\’s capsule nears ISS for rendezvous on Sunday (Update) | Phys.org
  • SpaceX Dragon Recovers from Frightening Propulsion System Failure – Sunday Docking Set | UniverseToday.com
  • SpaceX rocket launched, but problem with thrusters (Update 3)
  • SpaceX working to fix Dragon capsule\’s thrusters (Update 2) | phys.org
  • SpaceX company fixes Dragon capsule problem | phys.org
  • Dragon Spacecraft Glitch Was \’Frightening,\’ SpaceX Chief Elon Musk Says | Space.com

— UPDATES—

Russian Meteorite Chunk Found

Dennis Tito\’s Honeymoon Suite to Mars

— CURIOSITY UPDATE —

  • The \’Glitch\’
  • The spacecraft remained in communications at all scheduled communication windows on Wednesday, but it did not send recorded data, only current status information.
  • Status information revealed that the computer had not switched to the usual daily \”sleep\” mode when planned
  • On Thurs, Feb 28, the ground team for NASA\’s Mars rover Curiosity switched the rover to a redundant onboard computer in response to a memory issue on the computer that had been active
  • Flash Memory
  • The condition is related to a glitch in flash memory linked to the other, now-inactive, computer.
  • Diagnostic work in a testing simulation at JPL indicates the situation involved corrupted memory at an A-side memory location used for addressing memory files
  • It appears to have caused the computer to get stuck in an endless loop.
  • Protections and History
  • Curiosity has protections against such high-energy disruptions, but the problem was compounded by what appears to have been the location of the strike-in the directory, or \”table of contents,\” of the computer\’s memory
  • Similar problems were caused by high-energy solar and cosmic ray strikes on other space missions
  • Previous rovers experienced many so-called \”anomalies\” during the early part of their treks
  • Like many spacecraft Curiosity carries a pair of redundant main computers in order to have a backup available if one fails
  • Each of the computers, A-side and B-side, also has other redundant subsystems linked to just that computer
  • Operations
  • Curiosity is now operating on its B-side, as it did during part of the flight from Earth to Mars. It operated on its A-side from before the August 2012 landing through Wednesday.
  • Although scientific investigations by the rover were suspended the team hopes that Curiosity would resume science work in about a week.
  • While resuming operations on the B-side, they are also working to determine the best way to restore the A-side as a viable backup
  • What Happens Next
  • Even if the rover is fully operational again in a week, the amount of science it can perform is limited.
  • The sun comes between Mars and the Earth in early April, partially blocking the path for radio commands for an entire month
  • The Curiosity team had planned to send back science data from Mars during that period-called \”solar conjunction,\” but had decided not to send up any commands.
  • Multimedia
  • Image Galleries at JPL and Curiosity Mulimedia
  • Image This artist concept features NASA\’s Mars Science Laboratory Curiosity rover | mars.jpl.NASA.gov
  • Social Media
  • Curiosity Rover @MarsCuriosity
  • Further Reading / In the News
  • Curiosity Rover Has Computer Problems | UniverseToday.com
  • Mars Rover Curiosity Has First Big Malfunction news.NationalGeographic.com
  • Mars Science Laboratory: Computer Swap on Curiosity Rover | mars.jpl.NASA.gov
  • Computer Swap on Curiosity Rover – NASA Jet Propulsion Laboratory | jpl.nasa.gov

SCIENCE CALENDAR

Looking back

  • March 10, 1797: 216 years ago : Thomas Jefferson on paleontology : Thomas Jefferson (1743-1826) presented a paper on the megalonyx to the American Philosophical Society. It was published as \”A Memoir on the Discovery of Certain Bones of a Quadruped of the Clawed Kind in the Western Parts of Virginia,\” Transactions of American Philosophical Society 4:255-256, along with an account by Caspar Wistar (1761-1818). This is arguably the first American publication in paleontology, but the only paleontology paper written by Jefferson. In 1822, this huge extinct sloth was named Megalonyx jeffersoni by a French naturalist. (Megalonyx Gr. large claw). It was a bear-sized ground sloth, over 2 meters tall, widespread in North America during the last Ice Age

Looking up this week

  • Keep an eye out for …

  • Mercury, Venus, Mars | Now hidden in the Sun\’s glare

  • Jupiter | High in the S-SW after sunset, moving to the W/SW later in the evening
  • Saturn | ~10-11 pm | Rises in the E-SE moving to high in the Southern skies by dawn

  • Where to Find Comet PanSTARRS

  • 10* is about the width of your fist held at arm\’s length.
  • This diagram is drawn for a viewer near 40* north latitude (Denver, New York, Madrid) 30 minutes after sunset.
  • If you\’re south of there, the comet will be a little higher above your horizon early in the month than shown here.
  • North of 40°, it will be a little lower early in March than shown here.
  • SkyandTelescope.com/panstarrs

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